Commit Graph

9479 Commits

Author SHA1 Message Date
Nikolay Borisov
3347c48f27 btrfs: make btrfs_writepage_endio_finish_ordered btrfs_inode-centric
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
53ac7ead24 btrfs: make btrfs_invalidatepage work on btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
6fee248d2b btrfs: convert btrfs_inode_sectorsize to take btrfs_inode
It's counterintuitive to have a function named btrfs_inode_xxx which
takes a generic inode. Also move the function to btrfs_inode.h so that
it has access to the definition of struct btrfs_inode.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
90c0304c63 btrfs: make btrfs_dec_test_ordered_pending take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:18 +02:00
Nikolay Borisov
acbf1dd0fc btrfs: make ordered extent tracepoint take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Nikolay Borisov
6d072c8e29 btrfs: make btrfs_lookup_first_ordered_extent take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Nikolay Borisov
b79b724969 btrfs: make inode_tree_del take btrfs_inode
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Josef Bacik
ca9d473a3e btrfs: use BTRFS_NESTED_NEW_ROOT for double splits
I've made this change separate since it requires both of the newly added
NESTED flags and I didn't want to slip it into one of those changes.

If we do a double split of a node we can end up doing a
BTRFS_NESTED_SPLIT on level 0, which throws lockdep off because it
appears as a double lock.  Since we're maxed out on subclasses, use
BTRFS_NESTED_NEW_ROOT if we had to do a double split.  This is OK
because we won't have to do a double split if we had to insert a new
root, and the new root would be at a higher level anyway.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Josef Bacik
cf6f34aa3a btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots
The way we add new roots is confusing from a locking perspective for
lockdep.  We generally have the rule that we lock things in order from
highest level to lowest, but in the case of adding a new level to the
tree we actually allocate a new block for the root, which makes the
locking go in reverse.  A similar issue exists for snapshotting, we cow
the original root for the root of a new tree, however they're at the
same level.  Address this by using BTRFS_NESTING_NEW_ROOT for these
operations.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:17 +02:00
Josef Bacik
4dff97e690 btrfs: introduce BTRFS_NESTING_SPLIT for split blocks
If we are splitting a leaf/node, we could do something like the
following

lock(leaf)  BTRFS_NESTING_NORMAL
  lock(left) BTRFS_NESTING_LEFT + BTRFS_NESTING_COW
    push from leaf -> left
      reset path to point to left
        split left
          allocate new block, lock block BTRFS_NESTING_SPLIT

at the new block point we need to have a different nesting level,
because we have already used either BTRFS_NESTING_LEFT or
BTRFS_NESTING_RIGHT when pushing items from the original leaf into the
adjacent leaves.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Josef Bacik
bf59a5a216 btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW
For similar reasons as BTRFS_NESTING_COW, we need
BTRFS_NESTING_LEFT/RIGHT_COW.  The pattern is this

lock leaf -> BTRFS_NESTING_NORMAL
  cow leaf -> BTRFS_NESTING_COW
    split leaf
      lock left -> BTRFS_NESTING_LEFT
        cow left -> BTRFS_NESTING_LEFT_COW

We need this in order to indicate to lockdep that these locks are
discrete and are being taken in a safe order.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Josef Bacik
bf77467a93 btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHT
Our lockdep maps are based on rootid+level, however in some cases we
will lock adjacent blocks on the same level, namely in searching forward
or in split/balance.  Because of this lockdep will complain, so we need
a separate subclass to indicate to lockdep that these are different
locks.

lock leaf -> BTRFS_NESTING_NORMAL
  cow leaf -> BTRFS_NESTING_COW
    split leaf
       lock left -> BTRFS_NESTING_LEFT
       lock right -> BTRFS_NESTING_RIGHT

The above graph illustrates the need for this new nesting subclass.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Josef Bacik
9631e4cc1a btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks
When we COW a block we are holding a lock on the original block, and
then we lock the new COW block.  Because our lockdep maps are based on
root + level, this will make lockdep complain.  We need a way to
indicate a subclass for locking the COW'ed block, so plumb through our
btrfs_lock_nesting from btrfs_cow_block down to the btrfs_init_buffer,
and then introduce BTRFS_NESTING_COW to be used for cow'ing blocks.

The reason I've added all this extra infrastructure is because there
will be need of different nesting classes in follow up patches.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Josef Bacik
fd7ba1c120 btrfs: add nesting tags to the locking helpers
We will need these when we switch to an rwsem, so plumb in the
infrastructure here to use later on.  I violate the 80 character limit
some here because it'll be cleaned up later.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Josef Bacik
51899412dd btrfs: introduce btrfs_path::recurse
Our current tree locking stuff allows us to recurse with read locks if
we're already holding the write lock.  This is necessary for the space
cache inode, as we could be holding a lock on the root_tree root when we
need to cache a block group, and thus need to be able to read down the
root_tree to read in the inode cache.

We can get away with this in our current locking, but we won't be able
to with a rwsem.  Handle this by purposefully annotating the places
where we require recursion, so that in the future we can maybe come up
with a way to avoid the recursion.  In the case of the free space inode,
this will be superseded by the free space tree.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:16 +02:00
Josef Bacik
329ced799b btrfs: rename extent_buffer::lock_nested to extent_buffer::lock_recursed
Nested locking with lockdep and everything else refers to lock hierarchy
within the same lock map.  This is how we indicate the same locks for
different objects are ok to take in a specific order, for our use case
that would be to take the lock on a leaf and then take a lock on an
adjacent leaf.

What ->lock_nested _actually_ refers to is if we happen to already be
holding the write lock on the extent buffer and we're allowing a read
lock to be taken on that extent buffer, which is recursion.  Rename this
so we don't get confused when we switch to a rwsem and have to start
using the _nested helpers.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:15 +02:00
Nikolay Borisov
b9ba017fb0 btrfs: don't opencode sync_blockdev in btrfs_init_new_device
Instead of opencoding filemap_write_and_wait simply call syncblockdev as
it makes it abundantly clear what's going on and why this is used. No
semantics changes.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:15 +02:00
Nikolay Borisov
4ae312e972 btrfs: remove redundant code from btrfs_free_stale_devices
Following the refactor of btrfs_free_stale_devices in
7bcb8164ad ("btrfs: use device_list_mutex when removing stale devices")
fs_devices are freed after they have been iterated by the inner
list_for_each so the use-after-free fixed by introducing the break in
fd649f10c3 ("btrfs: Fix use-after-free when cleaning up fs_devs with
a single stale device") is no longer necessary. Just remove it
altogether. No functional changes.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:15 +02:00
Nikolay Borisov
44cab9ba37 btrfs: refactor locked condition in btrfs_init_new_device
Invert unlocked to locked and exploit the fact it can only ever be
modified if we are adding a new device to a seed filesystem. This allows
to simplify the check in error: label. No semantics changes.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:15 +02:00
Nikolay Borisov
f4cfa9bdd4 btrfs: use RCU for quick device check in btrfs_init_new_device
When adding a new device there's a mandatory check to see if a device is
being duplicated to the filesystem it's added to. Since this is a
read-only operations not necessary to take device_list_mutex and can simply
make do with an rcu-readlock.

Using just RCU is safe because there won't be another device add delete
running in parallel as btrfs_init_new_device is called only from
btrfs_ioctl_add_dev.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:15 +02:00
Qu Wenruo
d16c702fe4 btrfs: ctree: check key order before merging tree blocks
[BUG]
With a crafted image, btrfs can panic at btrfs_del_csums():

  kernel BUG at fs/btrfs/ctree.c:3188!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 0 PID: 1156 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9
  RIP: 0010:btrfs_set_item_key_safe+0x16c/0x180
  RSP: 0018:ffff976141257ab8 EFLAGS: 00010202
  RAX: 0000000000000001 RBX: ffff898a6b890930 RCX: 0000000004b70000
  RDX: 0000000000000000 RSI: ffff976141257bae RDI: ffff976141257acf
  RBP: ffff976141257b10 R08: 0000000000001000 R09: ffff9761412579a8
  R10: 0000000000000000 R11: 0000000000000000 R12: ffff976141257abe
  R13: 0000000000000003 R14: ffff898a6a8be578 R15: ffff976141257bae
  FS: 0000000000000000(0000) GS:ffff898a77a00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f779d9cd624 CR3: 000000022b2b4006 CR4: 00000000000206f0
  Call Trace:
  truncate_one_csum+0xac/0xf0
  btrfs_del_csums+0x24f/0x3a0
  __btrfs_free_extent.isra.72+0x5a7/0xbe0
  __btrfs_run_delayed_refs+0x539/0x1120
  btrfs_run_delayed_refs+0xdb/0x1b0
  btrfs_commit_transaction+0x52/0x950
  ? start_transaction+0x94/0x450
  transaction_kthread+0x163/0x190
  kthread+0x105/0x140
  ? btrfs_cleanup_transaction+0x560/0x560
  ? kthread_destroy_worker+0x50/0x50
  ret_from_fork+0x35/0x40
  Modules linked in:
  ---[ end trace 93bf9db00e6c374e ]---

[CAUSE]
This crafted image has a tricky key order corruption:

  checksum tree key (CSUM_TREE ROOT_ITEM 0)
  node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE
          ...
          key (EXTENT_CSUM EXTENT_CSUM 73785344) block 29757440 gen 19
          key (EXTENT_CSUM EXTENT_CSUM 77594624) block 29753344 gen 19
          ...

  leaf 29757440 items 5 free space 150 generation 19 owner CSUM_TREE
          item 0 key (EXTENT_CSUM EXTENT_CSUM 73785344) itemoff 2323 itemsize 1672
                  range start 73785344 end 75497472 length 1712128
          item 1 key (EXTENT_CSUM EXTENT_CSUM 75497472) itemoff 2319 itemsize 4
                  range start 75497472 end 75501568 length 4096
          item 2 key (EXTENT_CSUM EXTENT_CSUM 75501568) itemoff 579 itemsize 1740
                  range start 75501568 end 77283328 length 1781760
          item 3 key (EXTENT_CSUM EXTENT_CSUM 77283328) itemoff 575 itemsize 4
                  range start 77283328 end 77287424 length 4096
          item 4 key (EXTENT_CSUM EXTENT_CSUM 4120596480) itemoff 275 itemsize 300 <<<
                  range start 4120596480 end 4120903680 length 307200
  leaf 29753344 items 3 free space 1936 generation 19 owner CSUM_TREE
          item 0 key (18446744073457893366 EXTENT_CSUM 77594624) itemoff 2323 itemsize 1672
                  range start 77594624 end 79306752 length 1712128
          ...

Note the item 4 key of leaf 29757440, which is obviously too large, and
even larger than the first key of the next leaf.

However it still follows the key order in that tree block, thus tree
checker is unable to detect it at read time, since tree checker can only
work inside one leaf, thus such complex corruption can't be detected in
advance.

[FIX]
The next time to detect such problem is at tree block merge time,
which is in push_node_left(), balance_node_right(), push_leaf_left() or
push_leaf_right().

Now we check if the key order of the right-most key of the left node is
larger than the left-most key of the right node.

By this we don't need to call the full tree-checker, while still keeping
the key order correct as key order in each node is already checked by
tree checker thus we only need to check the above two slots.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202833
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:14 +02:00
Qu Wenruo
07cce5cf3b btrfs: extent-tree: kill the BUG_ON() in insert_inline_extent_backref()
[BUG]
With a crafted image, btrfs can panic at insert_inline_extent_backref():

  kernel BUG at fs/btrfs/extent-tree.c:1857!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 0 PID: 1117 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9
  RIP: 0010:insert_inline_extent_backref+0xcc/0xe0
  RSP: 0018:ffffac4dc1287be8 EFLAGS: 00010293
  RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000000001
  RDX: 0000000000001000 RSI: 0000000000000000 RDI: 0000000000000000
  RBP: ffffac4dc1287c28 R08: ffffac4dc1287ab8 R09: ffffac4dc1287ac0
  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
  R13: ffff8febef88a540 R14: ffff8febeaa7bc30 R15: 0000000000000000
  FS: 0000000000000000(0000) GS:ffff8febf7a00000(0000) knlGS:0000000000000000
  CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f663ace94c0 CR3: 0000000235698006 CR4: 00000000000206f0
  Call Trace:
  ? _cond_resched+0x1a/0x50
  __btrfs_inc_extent_ref.isra.64+0x7e/0x240
  ? btrfs_merge_delayed_refs+0xa5/0x330
  __btrfs_run_delayed_refs+0x653/0x1120
  btrfs_run_delayed_refs+0xdb/0x1b0
  btrfs_commit_transaction+0x52/0x950
  ? start_transaction+0x94/0x450
  transaction_kthread+0x163/0x190
  kthread+0x105/0x140
  ? btrfs_cleanup_transaction+0x560/0x560
  ? kthread_destroy_worker+0x50/0x50
  ret_from_fork+0x35/0x40
  Modules linked in:
  ---[ end trace 2ad8b3de903cf825 ]---

[CAUSE]
Due to extent tree corruption (still valid by itself, but bad cross
ref), we can allocate an extent which is still in extent tree.  The
offending tree block of that case is from csum tree.  The newly
allocated tree block is also for csum tree.

Then we will try to insert a tree block ref for the existing tree block
ref.

For a tree extent item, tree block can never be shared directly by the
same tree twice.  We have such BUG_ON() to prevent such problem, but
this is not a proper error handling.

[FIX]
Replace that BUG_ON() with proper error message and leaf dump for debug
build.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202829
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:14 +02:00
Qu Wenruo
1c2a07f598 btrfs: extent-tree: kill BUG_ON() in __btrfs_free_extent()
__btrfs_free_extent() is doing two things:

1. Reduce the refs number of an extent backref
   Either it's an inline extent backref (inside EXTENT/METADATA item) or
   a keyed extent backref (SHARED_* item).
   We only need to locate that backref line, either reduce the number or
   remove the backref line completely.

2. Update the refs count in EXTENT/METADATA_ITEM

During step 1), we will try to locate the EXTENT/METADATA_ITEM without
triggering another btrfs_search_slot() as fast path.

Only when we fail to locate that item, we will trigger another
btrfs_search_slot() to get that EXTENT/METADATA_ITEM after we
updated/deleted the backref line.

And we have a lot of strict checks on things like refs_to_drop against
extent refs and special case checks for single ref extents.

There are 7 BUG_ON()s, although they're doing correct checks, they can
be triggered by crafted images.

This patch improves the function:

- Introduce two examples to show what __btrfs_free_extent() is doing
  One inline backref case and one keyed case.  Should cover most cases.

- Kill all BUG_ON()s with proper error message and optional leaf dump

- Add comment to show the overall flow

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202819
[ The report triggers one BUG_ON() in __btrfs_free_extent() ]
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:14 +02:00
Qu Wenruo
f98b6215d7 btrfs: extent_io: do extra check for extent buffer read write functions
Although we have start, len check for extent buffer reader/write (e.g.
read_extent_buffer()), these checks have limitations:

- No overflow check
  Values like start = 1024 len = -1024 can still pass the basic
   (start + len) > eb->len check.

- Checks are not consistent
  For read_extent_buffer() we only check (start + len) against eb->len.
  While for memcmp_extent_buffer() we also check start against eb->len.

- Different error reporting mechanism
  We use WARN() in read_extent_buffer() but BUG() in
  memcpy_extent_buffer().

- Still modify memory if the request is obviously wrong
  In read_extent_buffer() even we find (start + len) > eb->len, we still
  call memset(dst, 0, len), which can easily cause memory access error
  if start + len overflows.

To address above problems, this patch creates a new common function to
check such access, check_eb_range().

- Add overflow check
  This function checks start, start + len against eb->len and overflow
  check.

- Unified checks

- Unified error reports
  Will call WARN() if CONFIG_BTRFS_DEBUG is configured.
  And also do btrfs_warn() message for non-debug build.

- Exit ASAP if check fails
  No more possible memory corruption.

- Add extra comment for @start @len used in those functions as it's
  sometimes confused with the logical addressing instead of a range
  inside the eb space

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202817
[ Inspired by above report, the report itself is already addressed ]
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ use check_add_overflow ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:14 +02:00
Nikolay Borisov
217f5004fe btrfs: rework error detection in init_tree_roots
To avoid duplicating 3 lines of code the error detection logic in
init_tree_roots is somewhat quirky. It first checks for the presence of
any error condition, then checks for the specific condition to perform
any specific actions. That's spurious because directly checking for
each respective error condition and doing the necessary steps is more
obvious. While at it change the -EUCLEAN to -EIO in case the extent
buffer is not read correctly, this is in line with other sites which
return -EIO when the eb couldn't be read.

Additionally it results in smaller code and the code reads
more linearly:

add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-95 (-95)
Function                                     old     new   delta
open_ctree                                 17243   17148     -95
Total: Before=113104, After=113009, chg -0.08%

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:14 +02:00
Qu Wenruo
e85fde5162 btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations
[BUG]
When quota is enabled for TEST_DEV, generic/013 sometimes fails like this:

  generic/013 14s ... _check_dmesg: something found in dmesg (see xfstests-dev/results//generic/013.dmesg)

And with the following metadata leak:

  BTRFS warning (device dm-3): qgroup 0/1370 has unreleased space, type 2 rsv 49152
  ------------[ cut here ]------------
  WARNING: CPU: 2 PID: 47912 at fs/btrfs/disk-io.c:4078 close_ctree+0x1dc/0x323 [btrfs]
  Call Trace:
   btrfs_put_super+0x15/0x17 [btrfs]
   generic_shutdown_super+0x72/0x110
   kill_anon_super+0x18/0x30
   btrfs_kill_super+0x17/0x30 [btrfs]
   deactivate_locked_super+0x3b/0xa0
   deactivate_super+0x40/0x50
   cleanup_mnt+0x135/0x190
   __cleanup_mnt+0x12/0x20
   task_work_run+0x64/0xb0
   __prepare_exit_to_usermode+0x1bc/0x1c0
   __syscall_return_slowpath+0x47/0x230
   do_syscall_64+0x64/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace a6cfd45ba80e4e06 ]---
  BTRFS error (device dm-3): qgroup reserved space leaked
  BTRFS info (device dm-3): disk space caching is enabled
  BTRFS info (device dm-3): has skinny extents

[CAUSE]
The qgroup preallocated meta rsv operations of that offending root are:

  btrfs_delayed_inode_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=131072
  btrfs_delayed_inode_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=131072
  btrfs_subvolume_reserve_metadata: rsv_meta_prealloc root=1370 num_bytes=49152
  btrfs_delayed_inode_release_metadata: convert_meta_prealloc root=1370 num_bytes=-131072
  btrfs_delayed_inode_release_metadata: convert_meta_prealloc root=1370 num_bytes=-131072

It's pretty obvious that, we reserve qgroup meta rsv in
btrfs_subvolume_reserve_metadata(), but doesn't have corresponding
release/convert calls in btrfs_subvolume_release_metadata().

This leads to the leakage.

[FIX]
To fix this bug, we should follow what we're doing in
btrfs_delalloc_reserve_metadata(), where we reserve qgroup space, and
add it to block_rsv->qgroup_rsv_reserved.

And free the qgroup reserved metadata space when releasing the
block_rsv.

To do this, we need to change the btrfs_subvolume_release_metadata() to
accept btrfs_root, and record the qgroup_to_release number, and call
btrfs_qgroup_convert_reserved_meta() for it.

Fixes: 733e03a0b2 ("btrfs: qgroup: Split meta rsv type into meta_prealloc and meta_pertrans")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:13 +02:00
Qu Wenruo
b4c5d8fdff btrfs: qgroup: fix wrong qgroup metadata reserve for delayed inode
For delayed inode facility, qgroup metadata is reserved for it, and
later freed.

However we're freeing more bytes than we reserved.
In btrfs_delayed_inode_reserve_metadata():

	num_bytes = btrfs_calc_metadata_size(fs_info, 1);
	...
		ret = btrfs_qgroup_reserve_meta_prealloc(root,
				fs_info->nodesize, true);
		...
		if (!ret) {
			node->bytes_reserved = num_bytes;

But in btrfs_delayed_inode_release_metadata():

	if (qgroup_free)
		btrfs_qgroup_free_meta_prealloc(node->root,
				node->bytes_reserved);
	else
		btrfs_qgroup_convert_reserved_meta(node->root,
				node->bytes_reserved);

This means, we're always releasing more qgroup metadata rsv than we have
reserved.

This won't trigger selftest warning, as btrfs qgroup metadata rsv has
extra protection against cases like quota enabled half-way.

But we still need to fix this problem any way.

This patch will use the same num_bytes for qgroup metadata rsv so we
could handle it correctly.

Fixes: f218ea6c47 ("btrfs: delayed-inode: Remove wrong qgroup meta reservation calls")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:13 +02:00
Josef Bacik
425c6ed648 btrfs: do not hold device_list_mutex when closing devices
The following lockdep splat

======================================================
WARNING: possible circular locking dependency detected
5.8.0-rc7-00169-g87212851a027-dirty #929 Not tainted
------------------------------------------------------
fsstress/8739 is trying to acquire lock:
ffff88bfd0eb0c90 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x43/0x70

but task is already holding lock:
ffff88bfbd16e538 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x6a/0x4a0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #10 (sb_pagefaults){.+.+}-{0:0}:
       __sb_start_write+0x129/0x210
       btrfs_page_mkwrite+0x6a/0x4a0
       do_page_mkwrite+0x4d/0xc0
       handle_mm_fault+0x103c/0x1730
       exc_page_fault+0x340/0x660
       asm_exc_page_fault+0x1e/0x30

-> #9 (&mm->mmap_lock#2){++++}-{3:3}:
       __might_fault+0x68/0x90
       _copy_to_user+0x1e/0x80
       perf_read+0x141/0x2c0
       vfs_read+0xad/0x1b0
       ksys_read+0x5f/0xe0
       do_syscall_64+0x50/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #8 (&cpuctx_mutex){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       perf_event_init_cpu+0x88/0x150
       perf_event_init+0x1db/0x20b
       start_kernel+0x3ae/0x53c
       secondary_startup_64+0xa4/0xb0

-> #7 (pmus_lock){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       perf_event_init_cpu+0x4f/0x150
       cpuhp_invoke_callback+0xb1/0x900
       _cpu_up.constprop.26+0x9f/0x130
       cpu_up+0x7b/0xc0
       bringup_nonboot_cpus+0x4f/0x60
       smp_init+0x26/0x71
       kernel_init_freeable+0x110/0x258
       kernel_init+0xa/0x103
       ret_from_fork+0x1f/0x30

-> #6 (cpu_hotplug_lock){++++}-{0:0}:
       cpus_read_lock+0x39/0xb0
       kmem_cache_create_usercopy+0x28/0x230
       kmem_cache_create+0x12/0x20
       bioset_init+0x15e/0x2b0
       init_bio+0xa3/0xaa
       do_one_initcall+0x5a/0x2e0
       kernel_init_freeable+0x1f4/0x258
       kernel_init+0xa/0x103
       ret_from_fork+0x1f/0x30

-> #5 (bio_slab_lock){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       bioset_init+0xbc/0x2b0
       __blk_alloc_queue+0x6f/0x2d0
       blk_mq_init_queue_data+0x1b/0x70
       loop_add+0x110/0x290 [loop]
       fq_codel_tcf_block+0x12/0x20 [sch_fq_codel]
       do_one_initcall+0x5a/0x2e0
       do_init_module+0x5a/0x220
       load_module+0x2459/0x26e0
       __do_sys_finit_module+0xba/0xe0
       do_syscall_64+0x50/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #4 (loop_ctl_mutex){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       lo_open+0x18/0x50 [loop]
       __blkdev_get+0xec/0x570
       blkdev_get+0xe8/0x150
       do_dentry_open+0x167/0x410
       path_openat+0x7c9/0xa80
       do_filp_open+0x93/0x100
       do_sys_openat2+0x22a/0x2e0
       do_sys_open+0x4b/0x80
       do_syscall_64+0x50/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #3 (&bdev->bd_mutex){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       blkdev_put+0x1d/0x120
       close_fs_devices.part.31+0x84/0x130
       btrfs_close_devices+0x44/0xb0
       close_ctree+0x296/0x2b2
       generic_shutdown_super+0x69/0x100
       kill_anon_super+0xe/0x30
       btrfs_kill_super+0x12/0x20
       deactivate_locked_super+0x29/0x60
       cleanup_mnt+0xb8/0x140
       task_work_run+0x6d/0xb0
       __prepare_exit_to_usermode+0x1cc/0x1e0
       do_syscall_64+0x5c/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       btrfs_run_dev_stats+0x49/0x480
       commit_cowonly_roots+0xb5/0x2a0
       btrfs_commit_transaction+0x516/0xa60
       sync_filesystem+0x6b/0x90
       generic_shutdown_super+0x22/0x100
       kill_anon_super+0xe/0x30
       btrfs_kill_super+0x12/0x20
       deactivate_locked_super+0x29/0x60
       cleanup_mnt+0xb8/0x140
       task_work_run+0x6d/0xb0
       __prepare_exit_to_usermode+0x1cc/0x1e0
       do_syscall_64+0x5c/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
       __mutex_lock+0x9f/0x930
       btrfs_commit_transaction+0x4bb/0xa60
       sync_filesystem+0x6b/0x90
       generic_shutdown_super+0x22/0x100
       kill_anon_super+0xe/0x30
       btrfs_kill_super+0x12/0x20
       deactivate_locked_super+0x29/0x60
       cleanup_mnt+0xb8/0x140
       task_work_run+0x6d/0xb0
       __prepare_exit_to_usermode+0x1cc/0x1e0
       do_syscall_64+0x5c/0x90
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}:
       __lock_acquire+0x1272/0x2310
       lock_acquire+0x9e/0x360
       __mutex_lock+0x9f/0x930
       btrfs_record_root_in_trans+0x43/0x70
       start_transaction+0xd1/0x5d0
       btrfs_dirty_inode+0x42/0xd0
       file_update_time+0xc8/0x110
       btrfs_page_mkwrite+0x10c/0x4a0
       do_page_mkwrite+0x4d/0xc0
       handle_mm_fault+0x103c/0x1730
       exc_page_fault+0x340/0x660
       asm_exc_page_fault+0x1e/0x30

other info that might help us debug this:

Chain exists of:
  &fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(sb_pagefaults);
                               lock(&mm->mmap_lock#2);
                               lock(sb_pagefaults);
  lock(&fs_info->reloc_mutex);

 *** DEADLOCK ***

3 locks held by fsstress/8739:
 #0: ffff88bee66eeb68 (&mm->mmap_lock#2){++++}-{3:3}, at: exc_page_fault+0x173/0x660
 #1: ffff88bfbd16e538 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x6a/0x4a0
 #2: ffff88bfbd16e630 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3da/0x5d0

stack backtrace:
CPU: 17 PID: 8739 Comm: fsstress Kdump: loaded Not tainted 5.8.0-rc7-00169-g87212851a027-dirty #929
Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
Call Trace:
 dump_stack+0x78/0xa0
 check_noncircular+0x165/0x180
 __lock_acquire+0x1272/0x2310
 ? btrfs_get_alloc_profile+0x150/0x210
 lock_acquire+0x9e/0x360
 ? btrfs_record_root_in_trans+0x43/0x70
 __mutex_lock+0x9f/0x930
 ? btrfs_record_root_in_trans+0x43/0x70
 ? lock_acquire+0x9e/0x360
 ? join_transaction+0x5d/0x450
 ? find_held_lock+0x2d/0x90
 ? btrfs_record_root_in_trans+0x43/0x70
 ? join_transaction+0x3d5/0x450
 ? btrfs_record_root_in_trans+0x43/0x70
 btrfs_record_root_in_trans+0x43/0x70
 start_transaction+0xd1/0x5d0
 btrfs_dirty_inode+0x42/0xd0
 file_update_time+0xc8/0x110
 btrfs_page_mkwrite+0x10c/0x4a0
 ? handle_mm_fault+0x5e/0x1730
 do_page_mkwrite+0x4d/0xc0
 ? __do_fault+0x32/0x150
 handle_mm_fault+0x103c/0x1730
 exc_page_fault+0x340/0x660
 ? asm_exc_page_fault+0x8/0x30
 asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x7faa6c9969c4

Was seen in testing.  The fix is similar to that of

  btrfs: open device without device_list_mutex

where we're holding the device_list_mutex and then grab the bd_mutex,
which pulls in a bunch of dependencies under the bd_mutex.  We only ever
call btrfs_close_devices() on mount failure or unmount, so we're save to
not have the device_list_mutex here.  We're already holding the
uuid_mutex which keeps us safe from any external modification of the
fs_devices.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:13 +02:00
Josef Bacik
62cf539120 btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks
When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex.  As such
we want to be holding as few locks as possible, so move this call
outside of the dev_replace->lock_finishing_cancel_unmount lock.  Since
we're modifying the fs_devices we need to make sure we're holding the
uuid_mutex here, so take that as well.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:12:13 +02:00
Nikolay Borisov
68abf36016 btrfs: remove alloc_list splice in btrfs_prepare_sprout
btrfs_prepare_sprout is called when the first rw device is added to a
seed filesystem. This means the filesystem can't have its alloc_list
be non-empty, since seed filesystems are read only. Simply remove the
code altogether.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:59 +02:00
Nikolay Borisov
427c8fddb1 btrfs: document some invariants of seed code
Without good understanding of how seed devices works it's hard to grok
some of what the code in open_seed_devices or btrfs_prepare_sprout does.

Add comments hopefully reducing some of the cognitive load.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:58 +02:00
Nikolay Borisov
944d3f9fac btrfs: switch seed device to list api
While this patch touches a bunch of files the conversion is
straighforward. Instead of using the implicit linked list anchored at
btrfs_fs_devices::seed the code is switched to using
list_for_each_entry.

Previous patches in the series already factored out code that processed
both main and seed devices so in those cases the factored out functions
are called on the main fs_devices and then on every seed dev inside
list_for_each_entry.

Using list api also allows to simplify deletion from the seed dev list
performed in btrfs_rm_device and btrfs_rm_dev_replace_free_srcdev by
substituting a while() loop with a simple list_del_init.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:58 +02:00
Nikolay Borisov
c4989c2fd0 btrfs: simplify setting/clearing fs_info to btrfs_fs_devices
It makes no sense to have sysfs-related routines be responsible for
properly initialising the fs_info pointer of struct btrfs_fs_device.
Instead this can be streamlined by making it the responsibility of
btrfs_init_devices_late to initialize it. That function already
initializes fs_info of every individual device in btrfs_fs_devices.

As far as clearing it is concerned it makes sense to move it to
close_fs_devices. That function is only called when struct
btrfs_fs_devices is no longer in use - either for holding seeds or
main devices for a mounted filesystem.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:58 +02:00
Nikolay Borisov
54eed6ae8d btrfs: make close_fs_devices return void
The return value of this function conveys absolutely no information.
All callers already check the state of fs_devices->opened to decide how
to proceed. So convert the function to returning void. While at it make
btrfs_close_devices also return void.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Nikolay Borisov
3712ccb7f1 btrfs: factor out loop logic from btrfs_free_extra_devids
This prepares the code to switching seeds devices to a proper list.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Nikolay Borisov
dc0ab488d2 btrfs: factor out reada loop in __reada_start_machine
This is in preparation for moving fs_devices to proper lists.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Nikolay Borisov
1028d1c48b btrfs: remove err variable from btrfs_get_extent
There's no practical reason too use 'err' as a variable to convey
errors. In fact it's value is either set explicitly in the beginning of
the function or it simply takes the value of 'ret'. Not conforming to
the usual pattern of having ret be the only variable used to convey
errors makes the code more error prone to bugs. In fact one such bug
was introduced by 6bf9e4bd6a ("btrfs: inode: Verify inode mode toi
avoid NULL pointer dereference") by assigning the error value to 'ret'
and not 'err'.

Let's fix that issue and make the function less tricky by leaving only
ret to convey error values.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Josef Bacik
0eb79294db btrfs: dio iomap DSYNC workaround
iomap dio will run generic_write_sync() for us if the iocb is DSYNC.
This is problematic for us because of 2 reasons:

1. we hold the inode_lock() during this operation, and we take it in
   generic_write_sync()
2. we hold a read lock on the dio_sem but take the write lock in fsync

Since we don't want to rip out this code right now, but reworking the
locking is a bit much to do at this point, work around this problem with
this masterpiece of a patch.

First, we clear DSYNC on the iocb so that the iomap stuff doesn't know
that it needs to handle the sync.  We save this fact in
current->journal_info, because we need to see do special things once
we're in iomap_begin, and we have no way to pass private information
into iomap_dio_rw().

Next we specify a separate iomap_dio_ops for sync, which implements an
->end_io() callback that gets called when the dio completes.  This is
important for AIO, because we really do need to run generic_write_sync()
if we complete asynchronously.  However if we're still in the submitting
context when we enter ->end_io() we clear the flag so that the submitter
knows they're the ones that needs to run generic_write_sync().

This is meant to be temporary.  We need to work out how to eliminate the
inode_lock() and the dio_sem in our fsync and use another mechanism to
protect these operations.

Tested-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Goldwyn Rodrigues
f85781fb50 btrfs: switch to iomap for direct IO
We're using direct io implementation based on buffer heads. This patch
switches to the new iomap infrastructure.

Switch from __blockdev_direct_IO() to iomap_dio_rw().  Rename
btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as
iomap_begin() for iomap direct I/O functions. This function allocates
and locks all the blocks required for the I/O.  btrfs_submit_direct() is
used as the submit_io() hook for direct I/O ops.

Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.

We don't need address_space.direct_IO() anymore: set it to noop.

Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.

Btrfs direct I/O is now done under i_rwsem, shared in case of reads and
exclusive in case of writes. This guards against simultaneous truncates.

Use iomap->iomap_end() to check for failed or incomplete direct I/O:

  - for writes, call __endio_write_update_ordered()
  - for reads, unlock extents

btrfs_dio_data is now hooked in iomap->private and not
current->journal_info. It carries the reservation variable and the
amount of data submitted, so we can calculate the amount of data to call
__endio_write_update_ordered in case of an error.

This patch removes last use of struct buffer_head from btrfs.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:57 +02:00
Qu Wenruo
154f7cb868 btrfs: add owner and fs_info to alloc_state io_tree
Commit 1c11b63eff ("btrfs: replace pending/pinned chunks lists with io
tree") introduced btrfs_device::alloc_state extent io tree, but it
doesn't initialize the fs_info and owner member.

This means the following features are not properly supported:

- Fs owner report for insert_state() error
  Without fs_info initialized, although btrfs_err() won't panic, it
  won't output which fs is causing the error.

- Wrong owner for trace events
  alloc_state will get the owner as pinned extents.

Fix this by assiging proper fs_info and owner for
btrfs_device::alloc_state.

Fixes: 1c11b63eff ("btrfs: replace pending/pinned chunks lists with io tree")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:56 +02:00
Marcos Paulo de Souza
4c448ce8b4 btrfs: make read_block_group_item return void
Since it's inclusion on 9afc66498a ("btrfs: block-group: refactor how
we read one block group item") this function always returned 0, so there
is no need to check for the returned value.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:56 +02:00
Leon Romanovsky
24646481fb btrfs: sysfs: fix unused-but-set-variable warnings
The compilation with W=1 generates the following warnings:
 fs/btrfs/sysfs.c:1630:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
  1630 |  int ret;
       |      ^~~
 fs/btrfs/sysfs.c:1629:6: warning: variable 'features' set but not used [-Wunused-but-set-variable]
  1629 |  u64 features;
       |      ^~~~~~~~

[ The unused variables are leftover from e410e34fad ("Revert "btrfs:
  synchronize incompat feature bits with sysfs files""), which needs
  to be properly fixed by moving feature bit manipulation from the sysfs
  context.  Silence the warning to save pepople time, we got several
  reports. ]

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:56 +02:00
Filipe Manana
487781796d btrfs: make fast fsyncs wait only for writeback
Currently regardless of a full or a fast fsync we always wait for ordered
extents to complete, and then start logging the inode after that. However
for fast fsyncs we can just wait for the writeback to complete, we don't
need to wait for the ordered extents to complete since we use the list of
modified extents maps to figure out which extents we must log and we can
get their checksums directly from the ordered extents that are still in
flight, otherwise look them up from the checksums tree.

Until commit b5e6c3e170 ("btrfs: always wait on ordered extents at
fsync time"), for fast fsyncs, we used to start logging without even
waiting for the writeback to complete first, we would wait for it to
complete after logging, while holding a transaction open, which lead to
performance issues when using cgroups and probably for other cases too,
as wait for IO while holding a transaction handle should be avoided as
much as possible. After that, for fast fsyncs, we started to wait for
ordered extents to complete before starting to log, which adds some
latency to fsyncs and we even got at least one report about a performance
drop which bisected to that particular change:

https://lore.kernel.org/linux-btrfs/20181109215148.GF23260@techsingularity.net/

This change makes fast fsyncs only wait for writeback to finish before
starting to log the inode, instead of waiting for both the writeback to
finish and for the ordered extents to complete. This brings back part of
the logic we had that extracts checksums from in flight ordered extents,
which are not yet in the checksums tree, and making sure transaction
commits wait for the completion of ordered extents previously logged
(by far most of the time they have already completed by the time a
transaction commit starts, resulting in no wait at all), to avoid any
data loss if an ordered extent completes after the transaction used to
log an inode is committed, followed by a power failure.

When there are no other tasks accessing the checksums and the subvolume
btrees, the ordered extent completion is pretty fast, typically taking
100 to 200 microseconds only in my observations. However when there are
other tasks accessing these btrees, ordered extent completion can take a
lot more time due to lock contention on nodes and leaves of these btrees.
I've seen cases over 2 milliseconds, which starts to be significant. In
particular when we do have concurrent fsyncs against different files there
is a lot of contention on the checksums btree, since we have many tasks
writing the checksums into the btree and other tasks that already started
the logging phase are doing lookups for checksums in the btree.

This change also turns all ranged fsyncs into full ranged fsyncs, which
is something we already did when not using the NO_HOLES features or when
doing a full fsync. This is to guarantee we never miss checksums due to
writeback having been triggered only for a part of an extent, and we end
up logging the full extent but only checksums for the written range, which
results in missing checksums after log replay. Allowing ranged fsyncs to
operate again only in the original range, when using the NO_HOLES feature
and doing a fast fsync is doable but requires some non trivial changes to
the writeback path, which can always be worked on later if needed, but I
don't think they are a very common use case.

Several tests were performed using fio for different numbers of concurrent
jobs, each writing and fsyncing its own file, for both sequential and
random file writes. The tests were run on bare metal, no virtualization,
on a box with 12 cores (Intel i7-8700), 64Gb of RAM and a NVMe device,
with a kernel configuration that is the default of typical distributions
(debian in this case), without debug options enabled (kasan, kmemleak,
slub debug, debug of page allocations, lock debugging, etc).

The following script that calls fio was used:

  $ cat test-fsync.sh
  #!/bin/bash

  DEV=/dev/nvme0n1
  MNT=/mnt/btrfs
  MOUNT_OPTIONS="-o ssd -o space_cache=v2"
  MKFS_OPTIONS="-d single -m single"

  if [ $# -ne 5 ]; then
    echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ BLOCK_SIZE [write|randwrite]"
    exit 1
  fi

  NUM_JOBS=$1
  FILE_SIZE=$2
  FSYNC_FREQ=$3
  BLOCK_SIZE=$4
  WRITE_MODE=$5

  if [ "$WRITE_MODE" != "write" ] && [ "$WRITE_MODE" != "randwrite" ]; then
    echo "Invalid WRITE_MODE, must be 'write' or 'randwrite'"
    exit 1
  fi

  cat <<EOF > /tmp/fio-job.ini
  [writers]
  rw=$WRITE_MODE
  fsync=$FSYNC_FREQ
  fallocate=none
  group_reporting=1
  direct=0
  bs=$BLOCK_SIZE
  ioengine=sync
  size=$FILE_SIZE
  directory=$MNT
  numjobs=$NUM_JOBS
  EOF

  echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

  echo
  echo "Using config:"
  echo
  cat /tmp/fio-job.ini
  echo

  umount $MNT &> /dev/null
  mkfs.btrfs -f $MKFS_OPTIONS $DEV
  mount $MOUNT_OPTIONS $DEV $MNT
  fio /tmp/fio-job.ini
  umount $MNT

The results were the following:

*************************
*** sequential writes ***
*************************

==== 1 job, 8GiB file, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=36.6MiB/s (38.4MB/s), 36.6MiB/s-36.6MiB/s (38.4MB/s-38.4MB/s), io=8192MiB (8590MB), run=223689-223689msec

After patch:

WRITE: bw=40.2MiB/s (42.1MB/s), 40.2MiB/s-40.2MiB/s (42.1MB/s-42.1MB/s), io=8192MiB (8590MB), run=203980-203980msec
(+9.8%, -8.8% runtime)

==== 2 jobs, 4GiB files, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=35.8MiB/s (37.5MB/s), 35.8MiB/s-35.8MiB/s (37.5MB/s-37.5MB/s), io=8192MiB (8590MB), run=228950-228950msec

After patch:

WRITE: bw=43.5MiB/s (45.6MB/s), 43.5MiB/s-43.5MiB/s (45.6MB/s-45.6MB/s), io=8192MiB (8590MB), run=188272-188272msec
(+21.5% throughput, -17.8% runtime)

==== 4 jobs, 2GiB files, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=50.1MiB/s (52.6MB/s), 50.1MiB/s-50.1MiB/s (52.6MB/s-52.6MB/s), io=8192MiB (8590MB), run=163446-163446msec

After patch:

WRITE: bw=64.5MiB/s (67.6MB/s), 64.5MiB/s-64.5MiB/s (67.6MB/s-67.6MB/s), io=8192MiB (8590MB), run=126987-126987msec
(+28.7% throughput, -22.3% runtime)

==== 8 jobs, 1GiB files, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=64.0MiB/s (68.1MB/s), 64.0MiB/s-64.0MiB/s (68.1MB/s-68.1MB/s), io=8192MiB (8590MB), run=126075-126075msec

After patch:

WRITE: bw=86.8MiB/s (91.0MB/s), 86.8MiB/s-86.8MiB/s (91.0MB/s-91.0MB/s), io=8192MiB (8590MB), run=94358-94358msec
(+35.6% throughput, -25.2% runtime)

==== 16 jobs, 512MiB files, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=79.8MiB/s (83.6MB/s), 79.8MiB/s-79.8MiB/s (83.6MB/s-83.6MB/s), io=8192MiB (8590MB), run=102694-102694msec

After patch:

WRITE: bw=107MiB/s (112MB/s), 107MiB/s-107MiB/s (112MB/s-112MB/s), io=8192MiB (8590MB), run=76446-76446msec
(+34.1% throughput, -25.6% runtime)

==== 32 jobs, 512MiB files, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=93.2MiB/s (97.7MB/s), 93.2MiB/s-93.2MiB/s (97.7MB/s-97.7MB/s), io=16.0GiB (17.2GB), run=175836-175836msec

After patch:

WRITE: bw=111MiB/s (117MB/s), 111MiB/s-111MiB/s (117MB/s-117MB/s), io=16.0GiB (17.2GB), run=147001-147001msec
(+19.1% throughput, -16.4% runtime)

==== 64 jobs, 512MiB files, fsync frequency 1, block size 64KiB ====

Before patch:

WRITE: bw=108MiB/s (114MB/s), 108MiB/s-108MiB/s (114MB/s-114MB/s), io=32.0GiB (34.4GB), run=302656-302656msec

After patch:

WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=246003-246003msec
(+23.1% throughput, -18.7% runtime)

************************
***   random writes  ***
************************

==== 1 job, 8GiB file, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=11.5MiB/s (12.0MB/s), 11.5MiB/s-11.5MiB/s (12.0MB/s-12.0MB/s), io=8192MiB (8590MB), run=714281-714281msec

After patch:

WRITE: bw=11.6MiB/s (12.2MB/s), 11.6MiB/s-11.6MiB/s (12.2MB/s-12.2MB/s), io=8192MiB (8590MB), run=705959-705959msec
(+0.9% throughput, -1.7% runtime)

==== 2 jobs, 4GiB files, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=12.8MiB/s (13.5MB/s), 12.8MiB/s-12.8MiB/s (13.5MB/s-13.5MB/s), io=8192MiB (8590MB), run=638101-638101msec

After patch:

WRITE: bw=13.1MiB/s (13.7MB/s), 13.1MiB/s-13.1MiB/s (13.7MB/s-13.7MB/s), io=8192MiB (8590MB), run=625374-625374msec
(+2.3% throughput, -2.0% runtime)

==== 4 jobs, 2GiB files, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=15.4MiB/s (16.2MB/s), 15.4MiB/s-15.4MiB/s (16.2MB/s-16.2MB/s), io=8192MiB (8590MB), run=531146-531146msec

After patch:

WRITE: bw=17.8MiB/s (18.7MB/s), 17.8MiB/s-17.8MiB/s (18.7MB/s-18.7MB/s), io=8192MiB (8590MB), run=460431-460431msec
(+15.6% throughput, -13.3% runtime)

==== 8 jobs, 1GiB files, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=19.9MiB/s (20.8MB/s), 19.9MiB/s-19.9MiB/s (20.8MB/s-20.8MB/s), io=8192MiB (8590MB), run=412664-412664msec

After patch:

WRITE: bw=22.2MiB/s (23.3MB/s), 22.2MiB/s-22.2MiB/s (23.3MB/s-23.3MB/s), io=8192MiB (8590MB), run=368589-368589msec
(+11.6% throughput, -10.7% runtime)

==== 16 jobs, 512MiB files, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=8192MiB (8590MB), run=279924-279924msec

After patch:

WRITE: bw=30.4MiB/s (31.9MB/s), 30.4MiB/s-30.4MiB/s (31.9MB/s-31.9MB/s), io=8192MiB (8590MB), run=269258-269258msec
(+3.8% throughput, -3.8% runtime)

==== 32 jobs, 512MiB files, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=36.9MiB/s (38.7MB/s), 36.9MiB/s-36.9MiB/s (38.7MB/s-38.7MB/s), io=16.0GiB (17.2GB), run=443581-443581msec

After patch:

WRITE: bw=41.6MiB/s (43.6MB/s), 41.6MiB/s-41.6MiB/s (43.6MB/s-43.6MB/s), io=16.0GiB (17.2GB), run=394114-394114msec
(+12.7% throughput, -11.2% runtime)

==== 64 jobs, 512MiB files, fsync frequency 16, block size 4KiB ====

Before patch:

WRITE: bw=45.9MiB/s (48.1MB/s), 45.9MiB/s-45.9MiB/s (48.1MB/s-48.1MB/s), io=32.0GiB (34.4GB), run=714614-714614msec

After patch:

WRITE: bw=48.8MiB/s (51.1MB/s), 48.8MiB/s-48.8MiB/s (51.1MB/s-51.1MB/s), io=32.0GiB (34.4GB), run=672087-672087msec
(+6.3% throughput, -6.0% runtime)

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:56 +02:00
Filipe Manana
75b463d2b4 btrfs: do not commit logs and transactions during link and rename operations
Since commit d4682ba03e ("Btrfs: sync log after logging new name") we
started to commit logs, and fallback to transaction commits when we failed
to log the new names or commit the logs, after link and rename operations
when the target inodes (or their parents) were previously logged in the
current transaction. This was to avoid losing directories despite an
explicit fsync on them when they are ancestors of some inode that got a
new named logged, due to a link or rename operation. However that adds the
cost of starting IO and waiting for it to complete, which can cause higher
latencies for applications.

Instead of doing that, just make sure that when we log a new name for an
inode we don't mark any of its ancestors as logged, so that if any one
does an fsync against any of them, without doing any other change on them,
the fsync commits the log. This way we only pay the cost of a log commit
(or a transaction commit if something goes wrong or a new block group was
created) if the application explicitly asks to fsync any of the parent
directories.

Using dbench, which mixes several filesystems operations including renames,
revealed some significant latency gains. The following script that uses
dbench was used to test this:

  #!/bin/bash

  DEV=/dev/nvme0n1
  MNT=/mnt/btrfs
  MOUNT_OPTIONS="-o ssd -o space_cache=v2"
  MKFS_OPTIONS="-m single -d single"
  THREADS=16

  echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
  mkfs.btrfs -f $MKFS_OPTIONS $DEV
  mount $MOUNT_OPTIONS $DEV $MNT

  dbench -t 300 -D $MNT $THREADS

  umount $MNT

The test was run on bare metal, no virtualization, on a box with 12 cores
(Intel i7-8700), 64Gb of RAM and using a NVMe device, with a kernel
configuration that is the default of typical distributions (debian in this
case), without debug options enabled (kasan, kmemleak, slub debug, debug
of page allocations, lock debugging, etc).

Results before this patch:

 Operation      Count    AvgLat    MaxLat
 ----------------------------------------
 NTCreateX    10750455     0.011   155.088
 Close         7896674     0.001     0.243
 Rename         455222     2.158  1101.947
 Unlink        2171189     0.067   121.638
 Deltree           256     2.425     7.816
 Mkdir             128     0.002     0.003
 Qpathinfo     9744323     0.006    21.370
 Qfileinfo     1707092     0.001     0.146
 Qfsinfo       1786756     0.001    11.228
 Sfileinfo      875612     0.003    21.263
 Find          3767281     0.025     9.617
 WriteX        5356924     0.011   211.390
 ReadX        16852694     0.003     9.442
 LockX           35008     0.002     0.119
 UnlockX         35008     0.001     0.138
 Flush          753458     4.252  1102.249

Throughput 1128.35 MB/sec  16 clients  16 procs  max_latency=1102.255 ms

Results after this patch:

16 clients, after

 Operation      Count    AvgLat    MaxLat
 ----------------------------------------
 NTCreateX    11471098     0.012   448.281
 Close         8426396     0.001     0.925
 Rename         485746     0.123   267.183
 Unlink        2316477     0.080    63.433
 Deltree           288     2.830    11.144
 Mkdir             144     0.003     0.010
 Qpathinfo    10397420     0.006    10.288
 Qfileinfo     1822039     0.001     0.169
 Qfsinfo       1906497     0.002    14.039
 Sfileinfo      934433     0.004     2.438
 Find          4019879     0.026    10.200
 WriteX        5718932     0.011   200.985
 ReadX        17981671     0.003    10.036
 LockX           37352     0.002     0.076
 UnlockX         37352     0.001     0.109
 Flush          804018     5.015   778.033

Throughput 1201.98 MB/sec  16 clients  16 procs  max_latency=778.036 ms
(+6.5% throughput, -29.4% max latency, -75.8% rename latency)

Test case generic/498 from fstests tests the scenario that the previously
mentioned commit fixed.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:56 +02:00
Filipe Manana
5522a27e59 btrfs: do not take the log_mutex of the subvolume when pinning the log
During a rename we pin the log to make sure no one commits a log that
reflects an ongoing rename operation, as it might result in a committed
log where it recorded the unlink of the old name without having recorded
the new name. However we are taking the subvolume's log_mutex before
incrementing the log_writers counter, which is not necessary since that
counter is atomic and we only remove the old name from the log and add
the new name to the log after we have incremented log_writers, ensuring
that no one can commit the log after we have removed the old name from
the log and before we added the new name to the log.

By taking the log_mutex lock we are just adding unnecessary contention on
the lock, which can become visible for workloads that mix renames with
fsyncs, writes for files opened with O_SYNC and unlink operations (if the
inode or its parent were fsynced before in the current transaction).

So just remove the lock and unlock of the subvolume's log_mutex at
btrfs_pin_log_trans().

Using dbench, which mixes different types of operations that end up taking
that mutex (fsyncs, renames, unlinks and writes into files opened with
O_SYNC) revealed some small gains. The following script that calls dbench
was used:

  #!/bin/bash

  DEV=/dev/nvme0n1
  MNT=/mnt/btrfs
  MOUNT_OPTIONS="-o ssd -o space_cache=v2"
  MKFS_OPTIONS="-m single -d single"
  THREADS=32

  echo "performance" | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
  mkfs.btrfs -f $MKFS_OPTIONS $DEV
  mount $MOUNT_OPTIONS $DEV $MNT

  dbench -s -t 600 -D $MNT $THREADS

  umount $MNT

The test was run on bare metal, no virtualization, on a box with 12 cores
(Intel i7-8700), 64Gb of RAM and using a NVMe device, with a kernel
configuration that is the default of typical distributions (debian in this
case), without debug options enabled (kasan, kmemleak, slub debug, debug
of page allocations, lock debugging, etc).

Results before this patch:

 Operation      Count    AvgLat    MaxLat
 ----------------------------------------
 NTCreateX    4410848     0.017   738.640
 Close        3240222     0.001     0.834
 Rename        186850     7.478  1272.476
 Unlink        890875     0.128   785.018
 Deltree          128     2.846    12.081
 Mkdir             64     0.002     0.003
 Qpathinfo    3997659     0.009    11.171
 Qfileinfo     701307     0.001     0.478
 Qfsinfo       733494     0.002     1.103
 Sfileinfo     359362     0.004     3.266
 Find         1546226     0.041     4.128
 WriteX       2202803     7.905  1376.989
 ReadX        6917775     0.003     3.887
 LockX          14392     0.002     0.043
 UnlockX        14392     0.001     0.085
 Flush         309225     0.128  1033.936

Throughput 231.555 MB/sec (sync open)  32 clients  32 procs  max_latency=1376.993 ms

Results after this patch:

Operation      Count    AvgLat    MaxLat
 ----------------------------------------
 NTCreateX    4603244     0.017   232.776
 Close        3381299     0.001     1.041
 Rename        194871     7.251  1073.165
 Unlink        929730     0.133   119.233
 Deltree          128     2.871    10.199
 Mkdir             64     0.002     0.004
 Qpathinfo    4171343     0.009    11.317
 Qfileinfo     731227     0.001     1.635
 Qfsinfo       765079     0.002     3.568
 Sfileinfo     374881     0.004     1.220
 Find         1612964     0.041     4.675
 WriteX       2296720     7.569  1178.204
 ReadX        7213633     0.003     3.075
 LockX          14976     0.002     0.076
 UnlockX        14976     0.001     0.061
 Flush         322635     0.102   579.505

Throughput 241.4 MB/sec (sync open)  32 clients  32 procs  max_latency=1178.207 ms
(+4.3% throughput, -14.4% max latency)

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:55 +02:00
David Sterba
1b51d6fce4 btrfs: send: remove indirect callback parameter for changed_cb
There's a custom callback passed to btrfs_compare_trees which happens to
be named exactly same as the existing function implementing it. This is
confusing and the indirection is not necessary for our needs. Compiler
is clever enough to call it directly so there's effectively no change.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:55 +02:00
David Sterba
8bb1cf1ba6 btrfs: scrub: rename ratelimit state varaible to avoid shadowing
There's already defined _rs within ctree.h:btrfs_printk_ratelimited,
local variables should not use _ to avoid such name clashes with
macro-local variables.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:55 +02:00
David Sterba
0af447d050 btrfs: remove unnecessarily shadowed variables
In btrfs_orphan_cleanup, there's another instance of fs_info, but it's
the same as the one we already have.

In btrfs_backref_finish_upper_links, rb_node is same type and used
as temporary cursor to the tree.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:55 +02:00
David Sterba
cb4c919830 btrfs: compression: move declarations to header
The declarations of compression algorithm callbacks are defined in the
.c file as they're used from there. Compiler warns that there are no
declarations for public functions when compiling lzo.c/zlib.c/zstd.c.
Fix that by moving the declarations to the header as it's the common
place for all of them.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:55 +02:00
David Sterba
9e6df7cedf btrfs: remove const from btrfs_feature_set_name
The function btrfs_feature_set_name returns a const char pointer, the
second const is not necessary and reported as a warning:

 In file included from fs/btrfs/space-info.c:6:
 fs/btrfs/sysfs.h:16:1: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
    16 | const char * const btrfs_feature_set_name(enum btrfs_feature_set set);
       | ^~~~~

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:55 +02:00
Qu Wenruo
e21139c621 btrfs: cleanup calculation of lockend in lock_and_cleanup_extent_if_need()
We're just doing rounding up to sectorsize to calculate the lockend.
There is no need to do the unnecessary length calculation, just direct
round_up() is enough.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:54 +02:00
Josef Bacik
c4923027bd btrfs: fix possible infinite loop in data async reclaim
Dave reported an issue where generic/102 would sometimes hang.  This
turned out to be because we'd get into this spot where we were no longer
making progress on data reservations because our exit condition was not
met.  The log is basically

while (!space_info->full && !list_empty(&space_info->tickets))
	flush_space(space_info, flush_state);

where flush state is our various flush states, but doesn't include
ALLOC_CHUNK_FORCE.  This is because we actually lead with allocating
chunks, and so the assumption was that once you got to the actual
flushing states you could no longer allocate chunks.  This was a stupid
assumption, because you could have deleted block groups that would be
reclaimed by a transaction commit, thus unsetting space_info->full.
This is essentially what happens with generic/102, and so sometimes
you'd get stuck in the flushing loop because we weren't allocating
chunks, but flushing space wasn't giving us what we needed to make
progress.

Fix this by adding ALLOC_CHUNK_FORCE to the end of our flushing states,
that way we will eventually bail out because we did end up with
space_info->full if we free'd a chunk previously.  Otherwise, as is the
case for this test, we'll allocate our chunk and continue on our happy
merry way.

Reported-by: David Sterba <dsterba@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:54 +02:00
Josef Bacik
1a7a92c8dd btrfs: add a comment explaining the data flush steps
The data flushing steps are not obvious to people other than myself and
Chris.  Write a giant comment explaining the reasoning behind each flush
step for data as well as why it is in that particular order.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:54 +02:00
Josef Bacik
5705674081 btrfs: do async reclaim for data reservations
Now that we have the data ticketing stuff in place, move normal data
reservations to use an async reclaim helper to satisfy tickets.  Before
we could have multiple tasks race in and both allocate chunks, resulting
in more data chunks than we would necessarily need.  Serializing these
allocations and making a single thread responsible for flushing will
only allocate chunks as needed, as well as cut down on transaction
commits and other flush related activities.

Priority reservations will still work as they have before, simply
trying to allocate a chunk until they can make their reservation.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:54 +02:00
Josef Bacik
cb3e393045 btrfs: flush delayed refs when trying to reserve data space
We can end up with freed extents in the delayed refs, and thus
may_commit_transaction() may not think we have enough pinned space to
commit the transaction and we'll ENOSPC early.  Handle this by running
the delayed refs in order to make sure pinned is uptodate before we try
to commit the transaction.

Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:54 +02:00
Josef Bacik
327feeeb2e btrfs: run delayed iputs before committing the transaction for data
Before we were waiting on iputs after we committed the transaction, but
this doesn't really make much sense.  We want to reclaim any space we
may have in order to be more likely to commit the transaction, due to
pinned space being added by running the delayed iputs.  Fix this by
making delayed iputs run before committing the transaction.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:53 +02:00
Josef Bacik
bb86bd3db8 btrfs: don't force commit if we are data
We used to unconditionally commit the transaction at least 2 times and
then on the 3rd try check against pinned space to make sure committing
the transaction was worth the effort.  This is overkill, we know nobody
is going to steal our reservation, and if we can't make our reservation
with the pinned amount simply bail out.

This also cleans up the passing of bytes_needed to
may_commit_transaction, as that was the thing we added into place in
order to accomplish this behavior.  We no longer need it so remove that
mess.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:53 +02:00
Josef Bacik
0282700135 btrfs: drop the commit_cycles stuff for data reservations
This was an old wart left over from how we previously did data
reservations.  Before we could have people race in and take a
reservation while we were flushing space, so we needed to make sure we
looped a few times before giving up.  Now that we're using the ticketing
infrastructure we don't have to worry about this and can drop the logic
altogether.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:53 +02:00
Josef Bacik
f3bda421c1 btrfs: use the same helper for data and metadata reservations
Now that data reservations follow the same pattern as metadata
reservations we can simply rename __reserve_metadata_bytes to
__reserve_bytes and use that helper for data reservations.

Things to keep in mind, btrfs_can_overcommit() returns 0 for data,
because we can never overcommit.  We also will never pass in FLUSH_ALL
for data, so we'll simply be added to the priority list and go straight
into handle_reserve_ticket.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:53 +02:00
Josef Bacik
0532a6f8b6 btrfs: serialize data reservations if we are flushing
Nikolay reported a problem where generic/371 would fail sometimes with a
slow drive.  The gist of the test is that we fallocate a file in
parallel with a pwrite of a different file.  These two files combined
are smaller than the file system, but sometimes the pwrite would ENOSPC.

A fair bit of investigation uncovered the fact that the fallocate
workload was racing in and grabbing the free space that the pwrite
workload was trying to free up so it could make its own reservation.
After a few loops of this eventually the pwrite workload would error out
with an ENOSPC.

We've had the same problem with metadata as well, and we serialized all
metadata allocations to satisfy this problem.  This wasn't usually a
problem with data because data reservations are more straightforward,
but obviously could still happen.

Fix this by not allowing reservations to occur if there are any pending
tickets waiting to be satisfied on the space info.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:53 +02:00
Josef Bacik
1004f6860f btrfs: use ticketing for data space reservations
Now that we have all the infrastructure in place, use the ticketing
infrastructure to make data allocations.  This still maintains the exact
same flushing behavior, but now we're using tickets to get our
reservations satisfied.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:53 +02:00
Josef Bacik
8698fc4eb7 btrfs: add btrfs_reserve_data_bytes and use it
Create a new function btrfs_reserve_data_bytes() in order to handle data
reservations.  This uses the new flush types and flush states to handle
making data reservations.

This patch specifically does not change any functionality, and is
purposefully not cleaned up in order to make bisection easier for the
future patches.  The new helper is identical to the old helper in how it
handles data reservations.  We first try to force a chunk allocation,
and then we run through the flush states all at once and in the same
order that they were done with the old helper.

Subsequent patches will clean this up and change the behavior of the
flushing, and it is important to keep those changes separate so we can
easily bisect down to the patch that caused the regression, rather than
the patch that made us start using the new infrastructure.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:52 +02:00
Josef Bacik
a1ed0a8216 btrfs: add the data transaction commit logic into may_commit_transaction
Data space flushing currently unconditionally commits the transaction
twice in a row, and the last time it checks if there's enough pinned
extents to satisfy its reservation before deciding to commit the
transaction for the 3rd and final time.

Encode this logic into may_commit_transaction().  In the next patch we
will pass in U64_MAX for bytes_needed the first two times, and the final
time we will pass in the actual bytes we need so the normal logic will
apply.

This patch exists solely to make the logical changes I will make to the
flushing state machine separate to make it easier to bisect any
performance related regressions.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:52 +02:00
Josef Bacik
058e6d1d26 btrfs: add flushing states for handling data reservations
Currently the way we do data reservations is by seeing if we have enough
space in our space_info.  If we do not and we're a normal inode we'll

1) Attempt to force a chunk allocation until we can't anymore.
2) If that fails we'll flush delalloc, then commit the transaction, then
   run the delayed iputs.

If we are a free space inode we're only allowed to force a chunk
allocation.  In order to use the normal flushing mechanism we need to
encode this into a flush state array for normal inodes.  Since both will
start with allocating chunks until the space info is full there is no
need to add this as a flush state, this will be handled specially.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:52 +02:00
Josef Bacik
448b966b49 btrfs: check tickets after waiting on ordered extents
Right now if the space is freed up after the ordered extents complete
(which is likely since the reservations are held until they complete),
we would do extra delalloc flushing before we'd notice that we didn't
have any more tickets.  Fix this by moving the tickets check after our
wait_ordered_extents check.

Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:52 +02:00
Josef Bacik
38d715f494 btrfs: use btrfs_start_delalloc_roots in shrink_delalloc
The original iteration of flushing had us flushing delalloc and then
checking to see if we could make our reservation, thus we were very
careful about how many pages we would flush at once.

But now that everything is async and we satisfy tickets as the space
becomes available we don't have to keep track of any of this, simply
try and flush the number of dirty inodes we may have in order to
reclaim space to make our reservation.  This cleans up our delalloc
flushing significantly.

The async_pages stuff is dropped because btrfs_start_delalloc_roots()
handles the case that we generate async extents for us, so we no longer
require this extra logic.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:52 +02:00
Josef Bacik
39753e4a3a btrfs: use the btrfs_space_info_free_bytes_may_use helper for delalloc
We are going to use the ticket infrastructure for data, so use the
btrfs_space_info_free_bytes_may_use() helper in
btrfs_free_reserved_data_space_noquota() so we get the
btrfs_try_granting_tickets call when we free our reservation.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:52 +02:00
Josef Bacik
99ffb43e5d btrfs: call btrfs_try_granting_tickets when reserving space
If we have compression on we could free up more space than we reserved,
and thus be able to make a space reservation.  Add the call for this
scenario.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:51 +02:00
Josef Bacik
2732798c9b btrfs: call btrfs_try_granting_tickets when unpinning anything
When unpinning we were only calling btrfs_try_granting_tickets() if
global_rsv->space_info == space_info, which is problematic because we
use ticketing for SYSTEM chunks, and want to use it for DATA as well.
Fix this by moving this call outside of that if statement.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:51 +02:00
Josef Bacik
3308234a7e btrfs: call btrfs_try_granting_tickets when freeing reserved bytes
We were missing a call to btrfs_try_granting_tickets in
btrfs_free_reserved_bytes, so add it to handle the case where we're able
to satisfy an allocation because we've freed a pending reservation.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:51 +02:00
Josef Bacik
c6c453032e btrfs: make ALLOC_CHUNK use the space info flags
We have traditionally used flush_space() to flush metadata space, so
we've been unconditionally using btrfs_metadata_alloc_profile() for our
profile to allocate a chunk. However if we're going to use this for
data we need to use btrfs_get_alloc_profile() on the space_info we pass
in.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:51 +02:00
Josef Bacik
920a9958c2 btrfs: make shrink_delalloc take space_info as an arg
Currently shrink_delalloc just looks up the metadata space info, but
this won't work if we're trying to reclaim space for data chunks.  We
get the right space_info we want passed into flush_space, so simply pass
that along to shrink_delalloc.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:51 +02:00
Josef Bacik
d7f81fac97 btrfs: handle U64_MAX for shrink_delalloc
Data allocations are going to want to pass in U64_MAX for flushing
space, adjust shrink_delalloc to handle this properly.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:51 +02:00
Josef Bacik
288be2d997 btrfs: remove orig from shrink_delalloc
We don't use this anywhere inside of shrink_delalloc since 17024ad0a0
("Btrfs: fix early ENOSPC due to delalloc"), remove it.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:50 +02:00
Josef Bacik
b49121393f btrfs: change nr to u64 in btrfs_start_delalloc_roots
We have btrfs_wait_ordered_roots() which takes a u64 for nr, but
btrfs_start_delalloc_roots() that takes an int for nr, which makes using
them in conjunction, especially for something like (u64)-1, annoying and
inconsistent.  Fix btrfs_start_delalloc_roots() to take a u64 for nr and
adjust start_delalloc_inodes() and it's callers appropriately.

This means we've adjusted start_delalloc_inodes() to take a pointer of
nr since we want to preserve the ability for start-delalloc_inodes() to
return an error, so simply make it do the nr adjusting as necessary.

Part of adjusting the callers to this means changing
btrfs_writeback_inodes_sb_nr() to take a u64 for items.  This may be
confusing because it seems unrelated, but the caller of
btrfs_writeback_inodes_sb_nr() already passes in a u64, it's just the
function variable that needs to be changed.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:50 +02:00
Nikolay Borisov
8e56008180 btrfs: remove fsid argument from btrfs_sysfs_update_sprout_fsid
It can be accessed from 'fs_devices' as it's identical to
fs_info->fs_devices. Also add a comment about why we are calling the
function. No semantic changes.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:50 +02:00
Nikolay Borisov
57297c1e8e btrfs: remove spurious BUG_ON in btrfs_get_extent
That BUG_ON cannot ever trigger because as the comment there states -
'err' is always set. Simply remove it as it brings no value.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:50 +02:00
Randy Dunlap
260db43cd2 btrfs: delete duplicated words + other fixes in comments
Delete repeated words in fs/btrfs/.
{to, the, a, and old}
and change "into 2 part" to "into 2 parts".

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:50 +02:00
Qu Wenruo
437490fed3 btrfs: tracepoints: output proper root owner for trace_find_free_extent()
The current trace event always output result like this:

 find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA)
 find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=4(METADATA)
 find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=2(EXTENT_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA)
 find_free_extent: root=2(EXTENT_TREE) len=4096 empty_size=0 flags=1(DATA)

T's saying we're allocating data extent for EXTENT tree, which is not
even possible.

It's because we always use EXTENT tree as the owner for
trace_find_free_extent() without using the @root from
btrfs_reserve_extent().

This patch will change the parameter to use proper @root for
trace_find_free_extent():

Now it looks much better:

 find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=4096 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=8192 empty_size=0 flags=1(DATA)
 find_free_extent: root=5(FS_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=7(CSUM_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=2(EXTENT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)
 find_free_extent: root=1(ROOT_TREE) len=16384 empty_size=0 flags=36(METADATA|DUP)

Reported-by: Hans van Kranenburg <hans@knorrie.org>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-10-07 12:06:49 +02:00
Linus Torvalds
4e3b9ce271 for-5.9-rc7-tag
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Merge tag 'for-5.9-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two more fixes.

  One is for a lockdep warning/lockup (also caught by syzbot), that one
  has been seen in practice. Regarding the other syzbot reports
  mentioned last time, they don't seem to be urgent and reliably
  reproducible so they'll be fixed later.

  The second fix is for a potential corruption when device replace
  finishes and the in-memory state of trim is not copied to the new
  device"

* tag 'for-5.9-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix filesystem corruption after a device replace
  btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks
  btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing
2020-10-02 10:09:40 -07:00
Filipe Manana
4c8f353272 btrfs: fix filesystem corruption after a device replace
We use a device's allocation state tree to track ranges in a device used
for allocated chunks, and we set ranges in this tree when allocating a new
chunk. However after a device replace operation, we were not setting the
allocated ranges in the new device's allocation state tree, so that tree
is empty after a device replace.

This means that a fitrim operation after a device replace will trim the
device ranges that have allocated chunks and extents, as we trim every
range for which there is not a range marked in the device's allocation
state tree. It is also important during chunk allocation, since the
device's allocation state is used to determine if a range is already
allocated when allocating a new chunk.

This is trivial to reproduce and the following script triggers the bug:

  $ cat reproducer.sh
  #!/bin/bash

  DEV1="/dev/sdg"
  DEV2="/dev/sdh"
  DEV3="/dev/sdi"

  wipefs -a $DEV1 $DEV2 $DEV3 &> /dev/null

  # Create a raid1 test fs on 2 devices.
  mkfs.btrfs -f -m raid1 -d raid1 $DEV1 $DEV2 > /dev/null
  mount $DEV1 /mnt/btrfs

  xfs_io -f -c "pwrite -S 0xab 0 10M" /mnt/btrfs/foo

  echo "Starting to replace $DEV1 with $DEV3"
  btrfs replace start -B $DEV1 $DEV3 /mnt/btrfs
  echo

  echo "Running fstrim"
  fstrim /mnt/btrfs
  echo

  echo "Unmounting filesystem"
  umount /mnt/btrfs

  echo "Mounting filesystem in degraded mode using $DEV3 only"
  wipefs -a $DEV1 $DEV2 &> /dev/null
  mount -o degraded $DEV3 /mnt/btrfs
  if [ $? -ne 0 ]; then
          dmesg | tail
          echo
          echo "Failed to mount in degraded mode"
          exit 1
  fi

  echo
  echo "File foo data (expected all bytes = 0xab):"
  od -A d -t x1 /mnt/btrfs/foo

  umount /mnt/btrfs

When running the reproducer:

  $ ./replace-test.sh
  wrote 10485760/10485760 bytes at offset 0
  10 MiB, 2560 ops; 0.0901 sec (110.877 MiB/sec and 28384.5216 ops/sec)
  Starting to replace /dev/sdg with /dev/sdi

  Running fstrim

  Unmounting filesystem
  Mounting filesystem in degraded mode using /dev/sdi only
  mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/sdi, missing codepage or helper program, or other error.
  [19581.748641] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi started
  [19581.803842] BTRFS info (device sdg): dev_replace from /dev/sdg (devid 1) to /dev/sdi finished
  [19582.208293] BTRFS info (device sdi): allowing degraded mounts
  [19582.208298] BTRFS info (device sdi): disk space caching is enabled
  [19582.208301] BTRFS info (device sdi): has skinny extents
  [19582.212853] BTRFS warning (device sdi): devid 2 uuid 1f731f47-e1bb-4f00-bfbb-9e5a0cb4ba9f is missing
  [19582.213904] btree_readpage_end_io_hook: 25839 callbacks suppressed
  [19582.213907] BTRFS error (device sdi): bad tree block start, want 30490624 have 0
  [19582.214780] BTRFS warning (device sdi): failed to read root (objectid=7): -5
  [19582.231576] BTRFS error (device sdi): open_ctree failed

  Failed to mount in degraded mode

So fix by setting all allocated ranges in the replace target device when
the replace operation is finishing, when we are holding the chunk mutex
and we can not race with new chunk allocations.

A test case for fstests follows soon.

Fixes: 1c11b63eff ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-30 19:40:51 +02:00
Josef Bacik
a466c85edc btrfs: move btrfs_rm_dev_replace_free_srcdev outside of all locks
When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex.  As such
we want to be holding as few locks as possible, so move this call
outside of the dev_replace->lock_finishing_cancel_unmount lock.  Since
we're modifying the fs_devices we need to make sure we're holding the
uuid_mutex here, so take that as well.

There's a report from syzbot probably hitting one of the cases where
the bd_mutex and device_list_mutex are taken in the wrong order, however
it's not with device replace, like this patch fixes. As there's no
reproducer available so far, we can't verify the fix.

https://lore.kernel.org/lkml/000000000000fc04d105afcf86d7@google.com/
dashboard link: https://syzkaller.appspot.com/bug?extid=84a0634dc5d21d488419

  WARNING: possible circular locking dependency detected
  5.9.0-rc5-syzkaller #0 Not tainted
  ------------------------------------------------------
  syz-executor.0/6878 is trying to acquire lock:
  ffff88804c17d780 (&bdev->bd_mutex){+.+.}-{3:3}, at: blkdev_put+0x30/0x520 fs/block_dev.c:1804

  but task is already holding lock:
  ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #4 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 btrfs_finish_chunk_alloc+0x281/0xf90 fs/btrfs/volumes.c:5255
	 btrfs_create_pending_block_groups+0x2f3/0x700 fs/btrfs/block-group.c:2109
	 __btrfs_end_transaction+0xf5/0x690 fs/btrfs/transaction.c:916
	 find_free_extent_update_loop fs/btrfs/extent-tree.c:3807 [inline]
	 find_free_extent+0x23b7/0x2e60 fs/btrfs/extent-tree.c:4127
	 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
	 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
	 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
	 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
	 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
	 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
	 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
	 do_writepages+0xec/0x290 mm/page-writeback.c:2352
	 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
	 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
	 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
	 wb_do_writeback fs/fs-writeback.c:2039 [inline]
	 wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
	 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
	 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
	 kthread+0x3b5/0x4a0 kernel/kthread.c:292
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

  -> #3 (sb_internal#2){.+.+}-{0:0}:
	 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
	 __sb_start_write+0x234/0x470 fs/super.c:1672
	 sb_start_intwrite include/linux/fs.h:1690 [inline]
	 start_transaction+0xbe7/0x1170 fs/btrfs/transaction.c:624
	 find_free_extent_update_loop fs/btrfs/extent-tree.c:3789 [inline]
	 find_free_extent+0x25e1/0x2e60 fs/btrfs/extent-tree.c:4127
	 btrfs_reserve_extent+0x166/0x460 fs/btrfs/extent-tree.c:4206
	 cow_file_range+0x3de/0x9b0 fs/btrfs/inode.c:1063
	 btrfs_run_delalloc_range+0x2cf/0x1410 fs/btrfs/inode.c:1838
	 writepage_delalloc+0x150/0x460 fs/btrfs/extent_io.c:3439
	 __extent_writepage+0x441/0xd00 fs/btrfs/extent_io.c:3653
	 extent_write_cache_pages.constprop.0+0x69d/0x1040 fs/btrfs/extent_io.c:4249
	 extent_writepages+0xcd/0x2b0 fs/btrfs/extent_io.c:4370
	 do_writepages+0xec/0x290 mm/page-writeback.c:2352
	 __writeback_single_inode+0x125/0x1400 fs/fs-writeback.c:1461
	 writeback_sb_inodes+0x53d/0xf40 fs/fs-writeback.c:1721
	 wb_writeback+0x2ad/0xd40 fs/fs-writeback.c:1894
	 wb_do_writeback fs/fs-writeback.c:2039 [inline]
	 wb_workfn+0x2dc/0x13e0 fs/fs-writeback.c:2080
	 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
	 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
	 kthread+0x3b5/0x4a0 kernel/kthread.c:292
	 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

  -> #2 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
	 __flush_work+0x60e/0xac0 kernel/workqueue.c:3041
	 wb_shutdown+0x180/0x220 mm/backing-dev.c:355
	 bdi_unregister+0x174/0x590 mm/backing-dev.c:872
	 del_gendisk+0x820/0xa10 block/genhd.c:933
	 loop_remove drivers/block/loop.c:2192 [inline]
	 loop_control_ioctl drivers/block/loop.c:2291 [inline]
	 loop_control_ioctl+0x3b1/0x480 drivers/block/loop.c:2257
	 vfs_ioctl fs/ioctl.c:48 [inline]
	 __do_sys_ioctl fs/ioctl.c:753 [inline]
	 __se_sys_ioctl fs/ioctl.c:739 [inline]
	 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
	 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (loop_ctl_mutex){+.+.}-{3:3}:
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 lo_open+0x19/0xd0 drivers/block/loop.c:1893
	 __blkdev_get+0x759/0x1aa0 fs/block_dev.c:1507
	 blkdev_get fs/block_dev.c:1639 [inline]
	 blkdev_open+0x227/0x300 fs/block_dev.c:1753
	 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
	 do_open fs/namei.c:3251 [inline]
	 path_openat+0x1b9a/0x2730 fs/namei.c:3368
	 do_filp_open+0x17e/0x3c0 fs/namei.c:3395
	 do_sys_openat2+0x16d/0x420 fs/open.c:1168
	 do_sys_open fs/open.c:1184 [inline]
	 __do_sys_open fs/open.c:1192 [inline]
	 __se_sys_open fs/open.c:1188 [inline]
	 __x64_sys_open+0x119/0x1c0 fs/open.c:1188
	 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&bdev->bd_mutex){+.+.}-{3:3}:
	 check_prev_add kernel/locking/lockdep.c:2496 [inline]
	 check_prevs_add kernel/locking/lockdep.c:2601 [inline]
	 validate_chain kernel/locking/lockdep.c:3218 [inline]
	 __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
	 lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
	 __mutex_lock_common kernel/locking/mutex.c:956 [inline]
	 __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
	 blkdev_put+0x30/0x520 fs/block_dev.c:1804
	 btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
	 btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
	 btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
	 close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
	 close_fs_devices fs/btrfs/volumes.c:1193 [inline]
	 btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
	 close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
	 generic_shutdown_super+0x144/0x370 fs/super.c:464
	 kill_anon_super+0x36/0x60 fs/super.c:1108
	 btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
	 deactivate_locked_super+0x94/0x160 fs/super.c:335
	 deactivate_super+0xad/0xd0 fs/super.c:366
	 cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
	 task_work_run+0xdd/0x190 kernel/task_work.c:141
	 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
	 exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
	 exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
	 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &bdev->bd_mutex --> sb_internal#2 --> &fs_devs->device_list_mutex

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_devs->device_list_mutex);
				 lock(sb_internal#2);
				 lock(&fs_devs->device_list_mutex);
    lock(&bdev->bd_mutex);

   *** DEADLOCK ***

  3 locks held by syz-executor.0/6878:
   #0: ffff88809070c0e0 (&type->s_umount_key#70){++++}-{3:3}, at: deactivate_super+0xa5/0xd0 fs/super.c:365
   #1: ffffffff8a5b37a8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_close_devices+0x23/0x1f0 fs/btrfs/volumes.c:1178
   #2: ffff8880908cfce0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: close_fs_devices.part.0+0x2e/0x800 fs/btrfs/volumes.c:1159

  stack backtrace:
  CPU: 0 PID: 6878 Comm: syz-executor.0 Not tainted 5.9.0-rc5-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
   __dump_stack lib/dump_stack.c:77 [inline]
   dump_stack+0x198/0x1fd lib/dump_stack.c:118
   check_noncircular+0x324/0x3e0 kernel/locking/lockdep.c:1827
   check_prev_add kernel/locking/lockdep.c:2496 [inline]
   check_prevs_add kernel/locking/lockdep.c:2601 [inline]
   validate_chain kernel/locking/lockdep.c:3218 [inline]
   __lock_acquire+0x2a96/0x5780 kernel/locking/lockdep.c:4426
   lock_acquire+0x1f3/0xae0 kernel/locking/lockdep.c:5006
   __mutex_lock_common kernel/locking/mutex.c:956 [inline]
   __mutex_lock+0x134/0x10e0 kernel/locking/mutex.c:1103
   blkdev_put+0x30/0x520 fs/block_dev.c:1804
   btrfs_close_bdev fs/btrfs/volumes.c:1117 [inline]
   btrfs_close_bdev fs/btrfs/volumes.c:1107 [inline]
   btrfs_close_one_device fs/btrfs/volumes.c:1133 [inline]
   close_fs_devices.part.0+0x1a4/0x800 fs/btrfs/volumes.c:1161
   close_fs_devices fs/btrfs/volumes.c:1193 [inline]
   btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179
   close_ctree+0x688/0x6cb fs/btrfs/disk-io.c:4149
   generic_shutdown_super+0x144/0x370 fs/super.c:464
   kill_anon_super+0x36/0x60 fs/super.c:1108
   btrfs_kill_super+0x38/0x50 fs/btrfs/super.c:2265
   deactivate_locked_super+0x94/0x160 fs/super.c:335
   deactivate_super+0xad/0xd0 fs/super.c:366
   cleanup_mnt+0x3a3/0x530 fs/namespace.c:1118
   task_work_run+0xdd/0x190 kernel/task_work.c:141
   tracehook_notify_resume include/linux/tracehook.h:188 [inline]
   exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
   exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:190
   syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:265
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x460027
  RSP: 002b:00007fff59216328 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  RAX: 0000000000000000 RBX: 0000000000076035 RCX: 0000000000460027
  RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fff592163d0
  RBP: 0000000000000333 R08: 0000000000000000 R09: 000000000000000b
  R10: 0000000000000005 R11: 0000000000000246 R12: 00007fff59217460
  R13: 0000000002df2a60 R14: 0000000000000000 R15: 00007fff59217460

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add syzbot reference ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-30 19:34:24 +02:00
Josef Bacik
313b085851 btrfs: move btrfs_scratch_superblocks into btrfs_dev_replace_finishing
We need to move the closing of the src_device out of all the device
replace locking, but we definitely want to zero out the superblock
before we commit the last time to make sure the device is properly
removed.  Handle this by pushing btrfs_scratch_superblocks into
btrfs_dev_replace_finishing, and then later on we'll move the src_device
closing and freeing stuff where we need it to be.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-25 16:40:22 +02:00
Christoph Hellwig
ed7b6b4f6e bdi: remove BDI_CAP_CGROUP_WRITEBACK
Just checking SB_I_CGROUPWB for cgroup writeback support is enough.
Either the file system allocates its own bdi (e.g. btrfs), in which case
it is known to support cgroup writeback, or the bdi comes from the block
layer, which always supports cgroup writeback.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-24 13:43:39 -06:00
Christoph Hellwig
55b2598e84 bdi: initialize ->ra_pages and ->io_pages in bdi_init
Set up a readahead size by default, as very few users have a good
reason to change it.  This means code, ecryptfs, and orangefs now
set up the values while they were previously missing it, while ubifs,
mtd and vboxsf manually set it to 0 to avoid readahead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Richard Weinberger <richard@nod.at> [ubifs, mtd]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-24 13:43:39 -06:00
Linus Torvalds
bffac4b543 for-5.9-rc6-tag
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Merge tag 'for-5.9-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "syzkaller started to hit us with reports, here's a fix for one type
  (stack overflow when printing checksums on read error).

  The other patch is a fix for sysfs object, we have a test for that and
  it leads to a crash."

* tag 'for-5.9-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix put of uninitialized kobject after seed device delete
  btrfs: fix overflow when copying corrupt csums for a message
2020-09-23 14:32:23 -07:00
Anand Jain
b5ddcffa37 btrfs: fix put of uninitialized kobject after seed device delete
The following test case leads to NULL kobject free error:

  mount seed /mnt
  add sprout to /mnt
  umount /mnt
  mount sprout to /mnt
  delete seed

  kobject: '(null)' (00000000dd2b87e4): is not initialized, yet kobject_put() is being called.
  WARNING: CPU: 1 PID: 15784 at lib/kobject.c:736 kobject_put+0x80/0x350
  RIP: 0010:kobject_put+0x80/0x350
  ::
  Call Trace:
  btrfs_sysfs_remove_devices_dir+0x6e/0x160 [btrfs]
  btrfs_rm_device.cold+0xa8/0x298 [btrfs]
  btrfs_ioctl+0x206c/0x22a0 [btrfs]
  ksys_ioctl+0xe2/0x140
  __x64_sys_ioctl+0x1e/0x29
  do_syscall_64+0x96/0x150
  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f4047c6288b
  ::

This is because, at the end of the seed device-delete, we try to remove
the seed's devid sysfs entry. But for the seed devices under the sprout
fs, we don't initialize the devid kobject yet. So add a kobject state
check, which takes care of the bug.

Fixes: 668e48af7a ("btrfs: sysfs, add devid/dev_state kobject and device attributes")
CC: stable@vger.kernel.org # 5.6+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-22 15:57:52 +02:00
Johannes Thumshirn
35be8851d1 btrfs: fix overflow when copying corrupt csums for a message
Syzkaller reported a buffer overflow in btree_readpage_end_io_hook()
when loop mounting a crafted image:

  detected buffer overflow in memcpy
  ------------[ cut here ]------------
  kernel BUG at lib/string.c:1129!
  invalid opcode: 0000 [#1] PREEMPT SMP KASAN
  CPU: 1 PID: 26 Comm: kworker/u4:2 Not tainted 5.9.0-rc4-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Workqueue: btrfs-endio-meta btrfs_work_helper
  RIP: 0010:fortify_panic+0xf/0x20 lib/string.c:1129
  RSP: 0018:ffffc90000e27980 EFLAGS: 00010286
  RAX: 0000000000000022 RBX: ffff8880a80dca64 RCX: 0000000000000000
  RDX: ffff8880a90860c0 RSI: ffffffff815dba07 RDI: fffff520001c4f22
  RBP: ffff8880a80dca00 R08: 0000000000000022 R09: ffff8880ae7318e7
  R10: 0000000000000000 R11: 0000000000077578 R12: 00000000ffffff6e
  R13: 0000000000000008 R14: ffffc90000e27a40 R15: 1ffff920001c4f3c
  FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000557335f440d0 CR3: 000000009647d000 CR4: 00000000001506e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   memcpy include/linux/string.h:405 [inline]
   btree_readpage_end_io_hook.cold+0x206/0x221 fs/btrfs/disk-io.c:642
   end_bio_extent_readpage+0x4de/0x10c0 fs/btrfs/extent_io.c:2854
   bio_endio+0x3cf/0x7f0 block/bio.c:1449
   end_workqueue_fn+0x114/0x170 fs/btrfs/disk-io.c:1695
   btrfs_work_helper+0x221/0xe20 fs/btrfs/async-thread.c:318
   process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
   worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
   kthread+0x3b5/0x4a0 kernel/kthread.c:292
   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
  Modules linked in:
  ---[ end trace b68924293169feef ]---
  RIP: 0010:fortify_panic+0xf/0x20 lib/string.c:1129
  RSP: 0018:ffffc90000e27980 EFLAGS: 00010286
  RAX: 0000000000000022 RBX: ffff8880a80dca64 RCX: 0000000000000000
  RDX: ffff8880a90860c0 RSI: ffffffff815dba07 RDI: fffff520001c4f22
  RBP: ffff8880a80dca00 R08: 0000000000000022 R09: ffff8880ae7318e7
  R10: 0000000000000000 R11: 0000000000077578 R12: 00000000ffffff6e
  R13: 0000000000000008 R14: ffffc90000e27a40 R15: 1ffff920001c4f3c
  FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f95b7c4d008 CR3: 000000009647d000 CR4: 00000000001506e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

The overflow happens, because in btree_readpage_end_io_hook() we assume
that we have found a 4 byte checksum instead of the real possible 32
bytes we have for the checksums.

With the fix applied:

[   35.726623] BTRFS: device fsid 815caf9a-dc43-4d2a-ac54-764b8333d765 devid 1 transid 5 /dev/loop0 scanned by syz-repro (215)
[   35.738994] BTRFS info (device loop0): disk space caching is enabled
[   35.738998] BTRFS info (device loop0): has skinny extents
[   35.743337] BTRFS warning (device loop0): loop0 checksum verify failed on 1052672 wanted 0xf9c035fc8d239a54 found 0x67a25c14b7eabcf9 level 0
[   35.743420] BTRFS error (device loop0): failed to read chunk root
[   35.745899] BTRFS error (device loop0): open_ctree failed

Reported-by: syzbot+e864a35d361e1d4e29a5@syzkaller.appspotmail.com
Fixes: d5178578bc ("btrfs: directly call into crypto framework for checksumming")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-21 12:39:21 +02:00
Linus Torvalds
fc4f28bb3d for-5.9-rc5-tag
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Merge tag 'for-5.9-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "One of the recent lockdep fixes introduced a bug that breaks the
  search ioctl, which is used by some applications (bees, compsize). The
  patch made it to stable trees so we need this fixup to make it work
  again"

* tag 'for-5.9-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix wrong address when faulting in pages in the search ioctl
2020-09-14 15:41:58 -07:00
Filipe Manana
1c78544eaa btrfs: fix wrong address when faulting in pages in the search ioctl
When faulting in the pages for the user supplied buffer for the search
ioctl, we are passing only the base address of the buffer to the function
fault_in_pages_writeable(). This means that after the first iteration of
the while loop that searches for leaves, when we have a non-zero offset,
stored in 'sk_offset', we try to fault in a wrong page range.

So fix this by adding the offset in 'sk_offset' to the base address of the
user supplied buffer when calling fault_in_pages_writeable().

Several users have reported that the applications compsize and bees have
started to operate incorrectly since commit a48b73eca4 ("btrfs: fix
potential deadlock in the search ioctl") was added to stable trees, and
these applications make heavy use of the search ioctls. This fixes their
issues.

Link: https://lore.kernel.org/linux-btrfs/632b888d-a3c3-b085-cdf5-f9bb61017d92@lechevalier.se/
Link: https://github.com/kilobyte/compsize/issues/34
Fixes: a48b73eca4 ("btrfs: fix potential deadlock in the search ioctl")
CC: stable@vger.kernel.org # 4.4+
Tested-by: A L <mail@lechevalier.se>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-14 17:27:16 +02:00
Linus Torvalds
edf6b0e1e4 for-5.9-rc4-tag
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Merge tag 'for-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few more fixes:

   - regression fix for a crash after failed snapshot creation

   - one more lockep fix: use nofs allocation when allocating missing
     device

   - fix reloc tree leak on degraded mount

   - make some extent buffer alignment checks less strict to mount
     filesystems created by btrfs-convert"

* tag 'for-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: fix NULL pointer dereference after failure to create snapshot
  btrfs: free data reloc tree on failed mount
  btrfs: require only sector size alignment for parent eb bytenr
  btrfs: fix lockdep splat in add_missing_dev
2020-09-12 12:28:39 -07:00
Filipe Manana
2d892ccdc1 btrfs: fix NULL pointer dereference after failure to create snapshot
When trying to get a new fs root for a snapshot during the transaction
at transaction.c:create_pending_snapshot(), if btrfs_get_new_fs_root()
fails we leave "pending->snap" pointing to an error pointer, and then
later at ioctl.c:create_snapshot() we dereference that pointer, resulting
in a crash:

  [12264.614689] BUG: kernel NULL pointer dereference, address: 00000000000007c4
  [12264.615650] #PF: supervisor write access in kernel mode
  [12264.616487] #PF: error_code(0x0002) - not-present page
  [12264.617436] PGD 0 P4D 0
  [12264.618328] Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
  [12264.619150] CPU: 0 PID: 2310635 Comm: fsstress Tainted: G        W         5.9.0-rc3-btrfs-next-67 #1
  [12264.619960] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
  [12264.621769] RIP: 0010:btrfs_mksubvol+0x438/0x4a0 [btrfs]
  [12264.622528] Code: bc ef ff ff (...)
  [12264.624092] RSP: 0018:ffffaa6fc7277cd8 EFLAGS: 00010282
  [12264.624669] RAX: 00000000fffffff4 RBX: ffff9d3e8f151a60 RCX: 0000000000000000
  [12264.625249] RDX: 0000000000000001 RSI: ffffffff9d56c9be RDI: fffffffffffffff4
  [12264.625830] RBP: ffff9d3e8f151b48 R08: 0000000000000000 R09: 0000000000000000
  [12264.626413] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffff4
  [12264.626994] R13: ffff9d3ede380538 R14: ffff9d3ede380500 R15: ffff9d3f61b2eeb8
  [12264.627582] FS:  00007f140d5d8200(0000) GS:ffff9d3fb5e00000(0000) knlGS:0000000000000000
  [12264.628176] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [12264.628773] CR2: 00000000000007c4 CR3: 000000020f8e8004 CR4: 00000000003706f0
  [12264.629379] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [12264.629994] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [12264.630594] Call Trace:
  [12264.631227]  btrfs_mksnapshot+0x7b/0xb0 [btrfs]
  [12264.631840]  __btrfs_ioctl_snap_create+0x16f/0x1a0 [btrfs]
  [12264.632458]  btrfs_ioctl_snap_create_v2+0xb0/0xf0 [btrfs]
  [12264.633078]  btrfs_ioctl+0x1864/0x3130 [btrfs]
  [12264.633689]  ? do_sys_openat2+0x1a7/0x2d0
  [12264.634295]  ? kmem_cache_free+0x147/0x3a0
  [12264.634899]  ? __x64_sys_ioctl+0x83/0xb0
  [12264.635488]  __x64_sys_ioctl+0x83/0xb0
  [12264.636058]  do_syscall_64+0x33/0x80
  [12264.636616]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

  (gdb) list *(btrfs_mksubvol+0x438)
  0x7c7b8 is in btrfs_mksubvol (fs/btrfs/ioctl.c:858).
  853		ret = 0;
  854		pending_snapshot->anon_dev = 0;
  855	fail:
  856		/* Prevent double freeing of anon_dev */
  857		if (ret && pending_snapshot->snap)
  858			pending_snapshot->snap->anon_dev = 0;
  859		btrfs_put_root(pending_snapshot->snap);
  860		btrfs_subvolume_release_metadata(root, &pending_snapshot->block_rsv);
  861	free_pending:
  862		if (pending_snapshot->anon_dev)

So fix this by setting "pending->snap" to NULL if we get an error from the
call to btrfs_get_new_fs_root() at transaction.c:create_pending_snapshot().

Fixes: 2dfb1e43f5 ("btrfs: preallocate anon block device at first phase of snapshot creation")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 21:18:35 +02:00
Josef Bacik
9e3aa80544 btrfs: free data reloc tree on failed mount
While testing a weird problem with -o degraded, I noticed I was getting
leaked root errors

  BTRFS warning (device loop0): writable mount is not allowed due to too many missing devices
  BTRFS error (device loop0): open_ctree failed
  BTRFS error (device loop0): leaked root -9-0 refcount 1

This is the DATA_RELOC root, which gets read before the other fs roots,
but is included in the fs roots radix tree.  Handle this by adding a
btrfs_drop_and_free_fs_root() on the data reloc root if it exists.  This
is ok to do here if we fail further up because we will only drop the ref
if we delete the root from the radix tree, and all other cleanup won't
be duplicated.

CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 14:51:15 +02:00
Qu Wenruo
ea57788eb7 btrfs: require only sector size alignment for parent eb bytenr
[BUG]
A completely sane converted fs will cause kernel warning at balance
time:

  [ 1557.188633] BTRFS info (device sda7): relocating block group 8162107392 flags data
  [ 1563.358078] BTRFS info (device sda7): found 11722 extents
  [ 1563.358277] BTRFS info (device sda7): leaf 7989321728 gen 95 total ptrs 213 free space 3458 owner 2
  [ 1563.358280] 	item 0 key (7984947200 169 0) itemoff 16250 itemsize 33
  [ 1563.358281] 		extent refs 1 gen 90 flags 2
  [ 1563.358282] 		ref#0: tree block backref root 4
  [ 1563.358285] 	item 1 key (7985602560 169 0) itemoff 16217 itemsize 33
  [ 1563.358286] 		extent refs 1 gen 93 flags 258
  [ 1563.358287] 		ref#0: shared block backref parent 7985602560
  [ 1563.358288] 			(parent 7985602560 is NOT ALIGNED to nodesize 16384)
  [ 1563.358290] 	item 2 key (7985635328 169 0) itemoff 16184 itemsize 33
  ...
  [ 1563.358995] BTRFS error (device sda7): eb 7989321728 invalid extent inline ref type 182
  [ 1563.358996] ------------[ cut here ]------------
  [ 1563.359005] WARNING: CPU: 14 PID: 2930 at 0xffffffff9f231766

Then with transaction abort, and obviously failed to balance the fs.

[CAUSE]
That mentioned inline ref type 182 is completely sane, it's
BTRFS_SHARED_BLOCK_REF_KEY, it's some extra check making kernel to
believe it's invalid.

Commit 64ecdb647d ("Btrfs: add one more sanity check for shared ref
type") introduced extra checks for backref type.

One of the requirement is, parent bytenr must be aligned to node size,
which is not correct.

One example is like this:

0	1G  1G+4K		2G 2G+4K
	|   |///////////////////|//|  <- A chunk starts at 1G+4K
            |   |	<- A tree block get reserved at bytenr 1G+4K

Then we have a valid tree block at bytenr 1G+4K, but not aligned to
nodesize (16K).

Such chunk is not ideal, but current kernel can handle it pretty well.
We may warn about such tree block in the future, but should not reject
them.

[FIX]
Change the alignment requirement from node size alignment to sector size
alignment.

Also, to make our lives a little easier, also output @iref when
btrfs_get_extent_inline_ref_type() failed, so we can locate the item
easier.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205475
Fixes: 64ecdb647d ("Btrfs: add one more sanity check for shared ref type")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
[ update comments and messages ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 14:51:05 +02:00
Josef Bacik
fccc0007b8 btrfs: fix lockdep splat in add_missing_dev
Nikolay reported a lockdep splat in generic/476 that I could reproduce
with btrfs/187.

  ======================================================
  WARNING: possible circular locking dependency detected
  5.9.0-rc2+ #1 Tainted: G        W
  ------------------------------------------------------
  kswapd0/100 is trying to acquire lock:
  ffff9e8ef38b6268 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330

  but task is already holding lock:
  ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (fs_reclaim){+.+.}-{0:0}:
	 fs_reclaim_acquire+0x65/0x80
	 slab_pre_alloc_hook.constprop.0+0x20/0x200
	 kmem_cache_alloc_trace+0x3a/0x1a0
	 btrfs_alloc_device+0x43/0x210
	 add_missing_dev+0x20/0x90
	 read_one_chunk+0x301/0x430
	 btrfs_read_sys_array+0x17b/0x1b0
	 open_ctree+0xa62/0x1896
	 btrfs_mount_root.cold+0x12/0xea
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 vfs_kern_mount.part.0+0x71/0xb0
	 btrfs_mount+0x10d/0x379
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 path_mount+0x434/0xc00
	 __x64_sys_mount+0xe3/0x120
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x7e/0x7e0
	 btrfs_chunk_alloc+0x125/0x3a0
	 find_free_extent+0xdf6/0x1210
	 btrfs_reserve_extent+0xb3/0x1b0
	 btrfs_alloc_tree_block+0xb0/0x310
	 alloc_tree_block_no_bg_flush+0x4a/0x60
	 __btrfs_cow_block+0x11a/0x530
	 btrfs_cow_block+0x104/0x220
	 btrfs_search_slot+0x52e/0x9d0
	 btrfs_lookup_inode+0x2a/0x8f
	 __btrfs_update_delayed_inode+0x80/0x240
	 btrfs_commit_inode_delayed_inode+0x119/0x120
	 btrfs_evict_inode+0x357/0x500
	 evict+0xcf/0x1f0
	 vfs_rmdir.part.0+0x149/0x160
	 do_rmdir+0x136/0x1a0
	 do_syscall_64+0x33/0x40
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
	 __lock_acquire+0x1184/0x1fa0
	 lock_acquire+0xa4/0x3d0
	 __mutex_lock+0x7e/0x7e0
	 __btrfs_release_delayed_node.part.0+0x3f/0x330
	 btrfs_evict_inode+0x24c/0x500
	 evict+0xcf/0x1f0
	 dispose_list+0x48/0x70
	 prune_icache_sb+0x44/0x50
	 super_cache_scan+0x161/0x1e0
	 do_shrink_slab+0x178/0x3c0
	 shrink_slab+0x17c/0x290
	 shrink_node+0x2b2/0x6d0
	 balance_pgdat+0x30a/0x670
	 kswapd+0x213/0x4c0
	 kthread+0x138/0x160
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    &delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(fs_reclaim);
				 lock(&fs_info->chunk_mutex);
				 lock(fs_reclaim);
    lock(&delayed_node->mutex);

   *** DEADLOCK ***

  3 locks held by kswapd0/100:
   #0: ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
   #1: ffffffffa9d65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290
   #2: ffff9e8e9da260e0 (&type->s_umount_key#48){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0

  stack backtrace:
  CPU: 1 PID: 100 Comm: kswapd0 Tainted: G        W         5.9.0-rc2+ #1
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
  Call Trace:
   dump_stack+0x92/0xc8
   check_noncircular+0x12d/0x150
   __lock_acquire+0x1184/0x1fa0
   lock_acquire+0xa4/0x3d0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   __mutex_lock+0x7e/0x7e0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   ? __btrfs_release_delayed_node.part.0+0x3f/0x330
   ? lock_acquire+0xa4/0x3d0
   ? btrfs_evict_inode+0x11e/0x500
   ? find_held_lock+0x2b/0x80
   __btrfs_release_delayed_node.part.0+0x3f/0x330
   btrfs_evict_inode+0x24c/0x500
   evict+0xcf/0x1f0
   dispose_list+0x48/0x70
   prune_icache_sb+0x44/0x50
   super_cache_scan+0x161/0x1e0
   do_shrink_slab+0x178/0x3c0
   shrink_slab+0x17c/0x290
   shrink_node+0x2b2/0x6d0
   balance_pgdat+0x30a/0x670
   kswapd+0x213/0x4c0
   ? _raw_spin_unlock_irqrestore+0x46/0x60
   ? add_wait_queue_exclusive+0x70/0x70
   ? balance_pgdat+0x670/0x670
   kthread+0x138/0x160
   ? kthread_create_worker_on_cpu+0x40/0x40
   ret_from_fork+0x1f/0x30

This is because we are holding the chunk_mutex when we call
btrfs_alloc_device, which does a GFP_KERNEL allocation.  We don't want
to switch that to a GFP_NOFS lock because this is the only place where
it matters.  So instead use memalloc_nofs_save() around the allocation
in order to avoid the lockdep splat.

Reported-by: Nikolay Borisov <nborisov@suse.com>
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07 14:50:57 +02:00
Linus Torvalds
dcdfd9cc28 for-5.9-rc3-tag
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Merge tag 'for-5.9-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "Two small fixes and a bunch of lockdep fixes for warnings that show up
  with an upcoming tree locking update but are valid with current locks
  as well"

* tag 'for-5.9-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: tree-checker: fix the error message for transid error
  btrfs: set the lockdep class for log tree extent buffers
  btrfs: set the correct lockdep class for new nodes
  btrfs: allocate scrub workqueues outside of locks
  btrfs: fix potential deadlock in the search ioctl
  btrfs: drop path before adding new uuid tree entry
  btrfs: block-group: fix free-space bitmap threshold
2020-09-01 18:36:45 -07:00
Qu Wenruo
f96d6960ab btrfs: tree-checker: fix the error message for transid error
The error message for inode transid is the same as for inode generation,
which makes us unable to detect the real problem.

Reported-by: Tyler Richmond <t.d.richmond@gmail.com>
Fixes: 496245cac5 ("btrfs: tree-checker: Verify inode item")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:16:05 +02:00
Josef Bacik
d3beaa253f btrfs: set the lockdep class for log tree extent buffers
These are special extent buffers that get rewound in order to lookup
the state of the tree at a specific point in time.  As such they do not
go through the normal initialization paths that set their lockdep class,
so handle them appropriately when they are created and before they are
locked.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:13:23 +02:00
Josef Bacik
ad24466588 btrfs: set the correct lockdep class for new nodes
When flipping over to the rw_semaphore I noticed I'd get a lockdep splat
in replace_path(), which is weird because we're swapping the reloc root
with the actual target root.  Turns out this is because we're using the
root->root_key.objectid as the root id for the newly allocated tree
block when setting the lockdep class, however we need to be using the
actual owner of this new block, which is saved in owner.

The affected path is through btrfs_copy_root as all other callers of
btrfs_alloc_tree_block (which calls init_new_buffer) have root_objectid
== root->root_key.objectid .

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:08:52 +02:00
Josef Bacik
e89c4a9c8e btrfs: allocate scrub workqueues outside of locks
I got the following lockdep splat while testing:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00172-g021118712e59 #932 Not tainted
  ------------------------------------------------------
  btrfs/229626 is trying to acquire lock:
  ffffffff828513f0 (cpu_hotplug_lock){++++}-{0:0}, at: alloc_workqueue+0x378/0x450

  but task is already holding lock:
  ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #7 (&fs_info->scrub_lock){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_scrub_dev+0x11c/0x630
	 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
	 btrfs_ioctl+0x2799/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #6 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_run_dev_stats+0x49/0x480
	 commit_cowonly_roots+0xb5/0x2a0
	 btrfs_commit_transaction+0x516/0xa60
	 sync_filesystem+0x6b/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0xe/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x29/0x60
	 cleanup_mnt+0xb8/0x140
	 task_work_run+0x6d/0xb0
	 __prepare_exit_to_usermode+0x1cc/0x1e0
	 do_syscall_64+0x5c/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #5 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_commit_transaction+0x4bb/0xa60
	 sync_filesystem+0x6b/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0xe/0x30
	 btrfs_kill_super+0x12/0x20
	 deactivate_locked_super+0x29/0x60
	 cleanup_mnt+0xb8/0x140
	 task_work_run+0x6d/0xb0
	 __prepare_exit_to_usermode+0x1cc/0x1e0
	 do_syscall_64+0x5c/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #4 (&fs_info->reloc_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_record_root_in_trans+0x43/0x70
	 start_transaction+0xd1/0x5d0
	 btrfs_dirty_inode+0x42/0xd0
	 touch_atime+0xa1/0xd0
	 btrfs_file_mmap+0x3f/0x60
	 mmap_region+0x3a4/0x640
	 do_mmap+0x376/0x580
	 vm_mmap_pgoff+0xd5/0x120
	 ksys_mmap_pgoff+0x193/0x230
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #3 (&mm->mmap_lock#2){++++}-{3:3}:
	 __might_fault+0x68/0x90
	 _copy_to_user+0x1e/0x80
	 perf_read+0x141/0x2c0
	 vfs_read+0xad/0x1b0
	 ksys_read+0x5f/0xe0
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (&cpuctx_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 perf_event_init_cpu+0x88/0x150
	 perf_event_init+0x1db/0x20b
	 start_kernel+0x3ae/0x53c
	 secondary_startup_64+0xa4/0xb0

  -> #1 (pmus_lock){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 perf_event_init_cpu+0x4f/0x150
	 cpuhp_invoke_callback+0xb1/0x900
	 _cpu_up.constprop.26+0x9f/0x130
	 cpu_up+0x7b/0xc0
	 bringup_nonboot_cpus+0x4f/0x60
	 smp_init+0x26/0x71
	 kernel_init_freeable+0x110/0x258
	 kernel_init+0xa/0x103
	 ret_from_fork+0x1f/0x30

  -> #0 (cpu_hotplug_lock){++++}-{0:0}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 cpus_read_lock+0x39/0xb0
	 alloc_workqueue+0x378/0x450
	 __btrfs_alloc_workqueue+0x15d/0x200
	 btrfs_alloc_workqueue+0x51/0x160
	 scrub_workers_get+0x5a/0x170
	 btrfs_scrub_dev+0x18c/0x630
	 btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
	 btrfs_ioctl+0x2799/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    cpu_hotplug_lock --> &fs_devs->device_list_mutex --> &fs_info->scrub_lock

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->scrub_lock);
				 lock(&fs_devs->device_list_mutex);
				 lock(&fs_info->scrub_lock);
    lock(cpu_hotplug_lock);

   *** DEADLOCK ***

  2 locks held by btrfs/229626:
   #0: ffff88bfe8bb86e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_scrub_dev+0xbd/0x630
   #1: ffff889dd3889518 (&fs_info->scrub_lock){+.+.}-{3:3}, at: btrfs_scrub_dev+0x11c/0x630

  stack backtrace:
  CPU: 15 PID: 229626 Comm: btrfs Kdump: loaded Not tainted 5.8.0-rc7-00172-g021118712e59 #932
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? alloc_workqueue+0x378/0x450
   cpus_read_lock+0x39/0xb0
   ? alloc_workqueue+0x378/0x450
   alloc_workqueue+0x378/0x450
   ? rcu_read_lock_sched_held+0x52/0x80
   __btrfs_alloc_workqueue+0x15d/0x200
   btrfs_alloc_workqueue+0x51/0x160
   scrub_workers_get+0x5a/0x170
   btrfs_scrub_dev+0x18c/0x630
   ? start_transaction+0xd1/0x5d0
   btrfs_dev_replace_by_ioctl.cold.21+0x10a/0x1d4
   btrfs_ioctl+0x2799/0x30a0
   ? do_sigaction+0x102/0x250
   ? lockdep_hardirqs_on_prepare+0xca/0x160
   ? _raw_spin_unlock_irq+0x24/0x30
   ? trace_hardirqs_on+0x1c/0xe0
   ? _raw_spin_unlock_irq+0x24/0x30
   ? do_sigaction+0x102/0x250
   ? ksys_ioctl+0x83/0xc0
   ksys_ioctl+0x83/0xc0
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x50/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This happens because we're allocating the scrub workqueues under the
scrub and device list mutex, which brings in a whole host of other
dependencies.

Because the work queue allocation is done with GFP_KERNEL, it can
trigger reclaim, which can lead to a transaction commit, which in turns
needs the device_list_mutex, it can lead to a deadlock. A different
problem for which this fix is a solution.

Fix this by moving the actual allocation outside of the
scrub lock, and then only take the lock once we're ready to actually
assign them to the fs_info.  We'll now have to cleanup the workqueues in
a few more places, so I've added a helper to do the refcount dance to
safely free the workqueues.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 14:06:02 +02:00
Josef Bacik
a48b73eca4 btrfs: fix potential deadlock in the search ioctl
With the conversion of the tree locks to rwsem I got the following
lockdep splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Not tainted
  ------------------------------------------------------
  compsize/11122 is trying to acquire lock:
  ffff889fabca8768 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x3e/0x90

  but task is already holding lock:
  ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (btrfs-fs-00){++++}-{3:3}:
	 down_write_nested+0x3b/0x70
	 __btrfs_tree_lock+0x24/0x120
	 btrfs_search_slot+0x756/0x990
	 btrfs_lookup_inode+0x3a/0xb4
	 __btrfs_update_delayed_inode+0x93/0x270
	 btrfs_async_run_delayed_root+0x168/0x230
	 btrfs_work_helper+0xd4/0x570
	 process_one_work+0x2ad/0x5f0
	 worker_thread+0x3a/0x3d0
	 kthread+0x133/0x150
	 ret_from_fork+0x1f/0x30

  -> #1 (&delayed_node->mutex){+.+.}-{3:3}:
	 __mutex_lock+0x9f/0x930
	 btrfs_delayed_update_inode+0x50/0x440
	 btrfs_update_inode+0x8a/0xf0
	 btrfs_dirty_inode+0x5b/0xd0
	 touch_atime+0xa1/0xd0
	 btrfs_file_mmap+0x3f/0x60
	 mmap_region+0x3a4/0x640
	 do_mmap+0x376/0x580
	 vm_mmap_pgoff+0xd5/0x120
	 ksys_mmap_pgoff+0x193/0x230
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&mm->mmap_lock#2){++++}-{3:3}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 __might_fault+0x68/0x90
	 _copy_to_user+0x1e/0x80
	 copy_to_sk.isra.32+0x121/0x300
	 search_ioctl+0x106/0x200
	 btrfs_ioctl_tree_search_v2+0x7b/0xf0
	 btrfs_ioctl+0x106f/0x30a0
	 ksys_ioctl+0x83/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0x90
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &mm->mmap_lock#2 --> &delayed_node->mutex --> btrfs-fs-00

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-fs-00);
				 lock(&delayed_node->mutex);
				 lock(btrfs-fs-00);
    lock(&mm->mmap_lock#2);

   *** DEADLOCK ***

  1 lock held by compsize/11122:
   #0: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  stack backtrace:
  CPU: 17 PID: 11122 Comm: compsize Kdump: loaded Not tainted 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? __might_fault+0x3e/0x90
   ? find_held_lock+0x72/0x90
   __might_fault+0x68/0x90
   ? __might_fault+0x3e/0x90
   _copy_to_user+0x1e/0x80
   copy_to_sk.isra.32+0x121/0x300
   ? btrfs_search_forward+0x2a6/0x360
   search_ioctl+0x106/0x200
   btrfs_ioctl_tree_search_v2+0x7b/0xf0
   btrfs_ioctl+0x106f/0x30a0
   ? __do_sys_newfstat+0x5a/0x70
   ? ksys_ioctl+0x83/0xc0
   ksys_ioctl+0x83/0xc0
   __x64_sys_ioctl+0x16/0x20
   do_syscall_64+0x50/0x90
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The problem is we're doing a copy_to_user() while holding tree locks,
which can deadlock if we have to do a page fault for the copy_to_user().
This exists even without my locking changes, so it needs to be fixed.
Rework the search ioctl to do the pre-fault and then
copy_to_user_nofault for the copying.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 13:56:27 +02:00
Josef Bacik
9771a5cf93 btrfs: drop path before adding new uuid tree entry
With the conversion of the tree locks to rwsem I got the following
lockdep splat:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925 Not tainted
  ------------------------------------------------------
  btrfs-uuid/7955 is trying to acquire lock:
  ffff88bfbafec0f8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  but task is already holding lock:
  ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (btrfs-uuid-00){++++}-{3:3}:
	 down_read_nested+0x3e/0x140
	 __btrfs_tree_read_lock+0x39/0x180
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x4bd/0x990
	 btrfs_uuid_tree_add+0x89/0x2d0
	 btrfs_uuid_scan_kthread+0x330/0x390
	 kthread+0x133/0x150
	 ret_from_fork+0x1f/0x30

  -> #0 (btrfs-root-00){++++}-{3:3}:
	 __lock_acquire+0x1272/0x2310
	 lock_acquire+0x9e/0x360
	 down_read_nested+0x3e/0x140
	 __btrfs_tree_read_lock+0x39/0x180
	 __btrfs_read_lock_root_node+0x3a/0x50
	 btrfs_search_slot+0x4bd/0x990
	 btrfs_find_root+0x45/0x1b0
	 btrfs_read_tree_root+0x61/0x100
	 btrfs_get_root_ref.part.50+0x143/0x630
	 btrfs_uuid_tree_iterate+0x207/0x314
	 btrfs_uuid_rescan_kthread+0x12/0x50
	 kthread+0x133/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(btrfs-uuid-00);
				 lock(btrfs-root-00);
				 lock(btrfs-uuid-00);
    lock(btrfs-root-00);

   *** DEADLOCK ***

  1 lock held by btrfs-uuid/7955:
   #0: ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180

  stack backtrace:
  CPU: 73 PID: 7955 Comm: btrfs-uuid Kdump: loaded Not tainted 5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925
  Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x165/0x180
   __lock_acquire+0x1272/0x2310
   lock_acquire+0x9e/0x360
   ? __btrfs_tree_read_lock+0x39/0x180
   ? btrfs_root_node+0x1c/0x1d0
   down_read_nested+0x3e/0x140
   ? __btrfs_tree_read_lock+0x39/0x180
   __btrfs_tree_read_lock+0x39/0x180
   __btrfs_read_lock_root_node+0x3a/0x50
   btrfs_search_slot+0x4bd/0x990
   btrfs_find_root+0x45/0x1b0
   btrfs_read_tree_root+0x61/0x100
   btrfs_get_root_ref.part.50+0x143/0x630
   btrfs_uuid_tree_iterate+0x207/0x314
   ? btree_readpage+0x20/0x20
   btrfs_uuid_rescan_kthread+0x12/0x50
   kthread+0x133/0x150
   ? kthread_create_on_node+0x60/0x60
   ret_from_fork+0x1f/0x30

This problem exists because we have two different rescan threads,
btrfs_uuid_scan_kthread which creates the uuid tree, and
btrfs_uuid_tree_iterate that goes through and updates or deletes any out
of date roots.  The problem is they both do things in different order.
btrfs_uuid_scan_kthread() reads the tree_root, and then inserts entries
into the uuid_root.  btrfs_uuid_tree_iterate() scans the uuid_root, but
then does a btrfs_get_fs_root() which can read from the tree_root.

It's actually easy enough to not be holding the path in
btrfs_uuid_scan_kthread() when we add a uuid entry, as we already drop
it further down and re-start the search when we loop.  So simply move
the path release before we add our entry to the uuid tree.

This also fixes a problem where we're holding a path open after we do
btrfs_end_transaction(), which has it's own problems.

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 13:46:15 +02:00
Marcos Paulo de Souza
e3e39c72b9 btrfs: block-group: fix free-space bitmap threshold
[BUG]
After commit 9afc66498a ("btrfs: block-group: refactor how we read one
block group item"), cache->length is being assigned after calling
btrfs_create_block_group_cache. This causes a problem since
set_free_space_tree_thresholds calculates the free-space threshold to
decide if the free-space tree should convert from extents to bitmaps.

The current code calls set_free_space_tree_thresholds with cache->length
being 0, which then makes cache->bitmap_high_thresh zero. This implies
the system will always use bitmap instead of extents, which is not
desired if the block group is not fragmented.

This behavior can be seen by a test that expects to repair systems
with FREE_SPACE_EXTENT and FREE_SPACE_BITMAP, but the current code only
created FREE_SPACE_BITMAP.

[FIX]
Call set_free_space_tree_thresholds after setting cache->length. There
is now a WARN_ON in set_free_space_tree_thresholds to help preventing
the same mistake to happen again in the future.

Link: https://github.com/kdave/btrfs-progs/issues/251
Fixes: 9afc66498a ("btrfs: block-group: refactor how we read one block group item")
CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-27 13:37:54 +02:00
Linus Torvalds
9907ab3714 for-5.9-rc2-tag
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Merge tag 'for-5.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fix swapfile activation on subvolumes with deleted snapshots

 - error value mixup when removing directory entries from tree log

 - fix lzo compression level reset after previous level setting

 - fix space cache memory leak after transaction abort

 - fix const function attribute

 - more error handling improvements

* tag 'for-5.9-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: detect nocow for swap after snapshot delete
  btrfs: check the right error variable in btrfs_del_dir_entries_in_log
  btrfs: fix space cache memory leak after transaction abort
  btrfs: use the correct const function attribute for btrfs_get_num_csums
  btrfs: reset compression level for lzo on remount
  btrfs: handle errors from async submission
2020-08-24 12:01:20 -07:00
Boris Burkov
a84d5d429f btrfs: detect nocow for swap after snapshot delete
can_nocow_extent and btrfs_cross_ref_exist both rely on a heuristic for
detecting a must cow condition which is not exactly accurate, but saves
unnecessary tree traversal. The incorrect assumption is that if the
extent was created in a generation smaller than the last snapshot
generation, it must be referenced by that snapshot. That is true, except
the snapshot could have since been deleted, without affecting the last
snapshot generation.

The original patch claimed a performance win from this check, but it
also leads to a bug where you are unable to use a swapfile if you ever
snapshotted the subvolume it's in. Make the check slower and more strict
for the swapon case, without modifying the general cow checks as a
compromise. Turning swap on does not seem to be a particularly
performance sensitive operation, so incurring a possibly unnecessary
btrfs_search_slot seems worthwhile for the added usability.

Note: Until the snapshot is competely cleaned after deletion,
check_committed_refs will still cause the logic to think that cow is
necessary, so the user must until 'btrfs subvolu sync' finished before
activating the swapfile swapon.

CC: stable@vger.kernel.org # 5.4+
Suggested-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-21 12:21:23 +02:00
Josef Bacik
fb2fecbad5 btrfs: check the right error variable in btrfs_del_dir_entries_in_log
With my new locking code dbench is so much faster that I tripped over a
transaction abort from ENOSPC.  This turned out to be because
btrfs_del_dir_entries_in_log was checking for ret == -ENOSPC, but this
function sets err on error, and returns err.  So instead of properly
marking the inode as needing a full commit, we were returning -ENOSPC
and aborting in __btrfs_unlink_inode.  Fix this by checking the proper
variable so that we return the correct thing in the case of ENOSPC.

The ENOENT needs to be checked, because btrfs_lookup_dir_item_index()
can return -ENOENT if the dir item isn't in the tree log (which would
happen if we hadn't fsync'ed this guy).  We actually handle that case in
__btrfs_unlink_inode, so it's an expected error to get back.

Fixes: 4a500fd178 ("Btrfs: Metadata ENOSPC handling for tree log")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note and comment about ENOENT ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-21 12:20:01 +02:00
Filipe Manana
bbc37d6e47 btrfs: fix space cache memory leak after transaction abort
If a transaction aborts it can cause a memory leak of the pages array of
a block group's io_ctl structure. The following steps explain how that can
happen:

1) Transaction N is committing, currently in state TRANS_STATE_UNBLOCKED
   and it's about to start writing out dirty extent buffers;

2) Transaction N + 1 already started and another task, task A, just called
   btrfs_commit_transaction() on it;

3) Block group B was dirtied (extents allocated from it) by transaction
   N + 1, so when task A calls btrfs_start_dirty_block_groups(), at the
   very beginning of the transaction commit, it starts writeback for the
   block group's space cache by calling btrfs_write_out_cache(), which
   allocates the pages array for the block group's io_ctl with a call to
   io_ctl_init(). Block group A is added to the io_list of transaction
   N + 1 by btrfs_start_dirty_block_groups();

4) While transaction N's commit is writing out the extent buffers, it gets
   an IO error and aborts transaction N, also setting the file system to
   RO mode;

5) Task A has already returned from btrfs_start_dirty_block_groups(), is at
   btrfs_commit_transaction() and has set transaction N + 1 state to
   TRANS_STATE_COMMIT_START. Immediately after that it checks that the
   filesystem was turned to RO mode, due to transaction N's abort, and
   jumps to the "cleanup_transaction" label. After that we end up at
   btrfs_cleanup_one_transaction() which calls btrfs_cleanup_dirty_bgs().
   That helper finds block group B in the transaction's io_list but it
   never releases the pages array of the block group's io_ctl, resulting in
   a memory leak.

In fact at the point when we are at btrfs_cleanup_dirty_bgs(), the pages
array points to pages that were already released by us at
__btrfs_write_out_cache() through the call to io_ctl_drop_pages(). We end
up freeing the pages array only after waiting for the ordered extent to
complete through btrfs_wait_cache_io(), which calls io_ctl_free() to do
that. But in the transaction abort case we don't wait for the space cache's
ordered extent to complete through a call to btrfs_wait_cache_io(), so
that's why we end up with a memory leak - we wait for the ordered extent
to complete indirectly by shutting down the work queues and waiting for
any jobs in them to complete before returning from close_ctree().

We can solve the leak simply by freeing the pages array right after
releasing the pages (with the call to io_ctl_drop_pages()) at
__btrfs_write_out_cache(), since we will never use it anymore after that
and the pages array points to already released pages at that point, which
is currently not a problem since no one will use it after that, but not a
good practice anyway since it can easily lead to use-after-free issues.

So fix this by freeing the pages array right after releasing the pages at
__btrfs_write_out_cache().

This issue can often be reproduced with test case generic/475 from fstests
and kmemleak can detect it and reports it with the following trace:

unreferenced object 0xffff9bbf009fa600 (size 512):
  comm "fsstress", pid 38807, jiffies 4298504428 (age 22.028s)
  hex dump (first 32 bytes):
    00 a0 7c 4d 3d ed ff ff 40 a0 7c 4d 3d ed ff ff  ..|M=...@.|M=...
    80 a0 7c 4d 3d ed ff ff c0 a0 7c 4d 3d ed ff ff  ..|M=.....|M=...
  backtrace:
    [<00000000f4b5cfe2>] __kmalloc+0x1a8/0x3e0
    [<0000000028665e7f>] io_ctl_init+0xa7/0x120 [btrfs]
    [<00000000a1f95b2d>] __btrfs_write_out_cache+0x86/0x4a0 [btrfs]
    [<00000000207ea1b0>] btrfs_write_out_cache+0x7f/0xf0 [btrfs]
    [<00000000af21f534>] btrfs_start_dirty_block_groups+0x27b/0x580 [btrfs]
    [<00000000c3c23d44>] btrfs_commit_transaction+0xa6f/0xe70 [btrfs]
    [<000000009588930c>] create_subvol+0x581/0x9a0 [btrfs]
    [<000000009ef2fd7f>] btrfs_mksubvol+0x3fb/0x4a0 [btrfs]
    [<00000000474e5187>] __btrfs_ioctl_snap_create+0x119/0x1a0 [btrfs]
    [<00000000708ee349>] btrfs_ioctl_snap_create_v2+0xb0/0xf0 [btrfs]
    [<00000000ea60106f>] btrfs_ioctl+0x12c/0x3130 [btrfs]
    [<000000005c923d6d>] __x64_sys_ioctl+0x83/0xb0
    [<0000000043ace2c9>] do_syscall_64+0x33/0x80
    [<00000000904efbce>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:39:46 +02:00
David Sterba
604997b4a3 btrfs: use the correct const function attribute for btrfs_get_num_csums
The build robot reports

compiler: h8300-linux-gcc (GCC) 9.3.0
   In file included from fs/btrfs/tests/extent-map-tests.c:8:
>> fs/btrfs/tests/../ctree.h:2166:8: warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
    2166 | size_t __const btrfs_get_num_csums(void);
         |        ^~~~~~~

The function attribute for const does not follow the expected scheme and
in this case is confused with a const type qualifier.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:39:21 +02:00
Marcos Paulo de Souza
282dd7d771 btrfs: reset compression level for lzo on remount
Currently a user can set mount "-o compress" which will set the
compression algorithm to zlib, and use the default compress level for
zlib (3):

  relatime,compress=zlib:3,space_cache

If the user remounts the fs using "-o compress=lzo", then the old
compress_level is used:

  relatime,compress=lzo:3,space_cache

But lzo does not expose any tunable compression level. The same happens
if we set any compress argument with different level, also with zstd.

Fix this by resetting the compress_level when compress=lzo is
specified.  With the fix applied, lzo is shown without compress level:

  relatime,compress=lzo,space_cache

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:39:12 +02:00
Johannes Thumshirn
c965d6402f btrfs: handle errors from async submission
Btrfs' async submit mechanism is able to handle errors in the submission
path and the meta-data async submit function correctly passes the error
code to the caller.

In btrfs_submit_bio_start() and btrfs_submit_bio_start_direct_io() we're
not handling the errors returned by btrfs_csum_one_bio() correctly though
and simply call BUG_ON(). This is unnecessary as the caller of these two
functions - run_one_async_start - correctly checks for the return values
and sets the status of the async_submit_bio. The actual bio submission
will be handled later on by run_one_async_done only if
async_submit_bio::status is 0, so the data won't be written if we
encountered an error in the checksum process.

Simply return the error from btrfs_csum_one_bio() to the async submitters,
like it's done in btree_submit_bio_start().

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-19 18:26:14 +02:00
Linus Torvalds
23c2c8c6fa for-5.9-tag
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Merge tag 'for-5.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull more btrfs updates from David Sterba:
 "One minor update, the rest are fixes that have arrived a bit late for
  the first batch. There are also some recent fixes for bugs that were
  discovered during the merge window and pop up during testing.

  User visible change:

   - show correct subvolume path in /proc/mounts for bind mounts

  Fixes:

   - fix compression messages when remounting with different level or
     compression algorithm

   - tree-log: fix some memory leaks on error handling paths

   - restore I_VERSION on remount

   - fix return values and error code mixups

   - fix umount crash with quotas enabled when removing sysfs files

   - fix trim range on a shrunk device"

* tag 'for-5.9-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: trim: fix underflow in trim length to prevent access beyond device boundary
  btrfs: fix return value mixup in btrfs_get_extent
  btrfs: sysfs: fix NULL pointer dereference at btrfs_sysfs_del_qgroups()
  btrfs: check correct variable after allocation in btrfs_backref_iter_alloc
  btrfs: make sure SB_I_VERSION doesn't get unset by remount
  btrfs: fix memory leaks after failure to lookup checksums during inode logging
  btrfs: don't show full path of bind mounts in subvol=
  btrfs: fix messages after changing compression level by remount
  btrfs: only search for left_info if there is no right_info in try_merge_free_space
  btrfs: inode: fix NULL pointer dereference if inode doesn't need compression
2020-08-13 12:26:18 -07:00
Qu Wenruo
c57dd1f2f6 btrfs: trim: fix underflow in trim length to prevent access beyond device boundary
[BUG]
The following script can lead to tons of beyond device boundary access:

  mkfs.btrfs -f $dev -b 10G
  mount $dev $mnt
  trimfs $mnt
  btrfs filesystem resize 1:-1G $mnt
  trimfs $mnt

[CAUSE]
Since commit 929be17a9b ("btrfs: Switch btrfs_trim_free_extents to
find_first_clear_extent_bit"), we try to avoid trimming ranges that's
already trimmed.

So we check device->alloc_state by finding the first range which doesn't
have CHUNK_TRIMMED and CHUNK_ALLOCATED not set.

But if we shrunk the device, that bits are not cleared, thus we could
easily got a range starts beyond the shrunk device size.

This results the returned @start and @end are all beyond device size,
then we call "end = min(end, device->total_bytes -1);" making @end
smaller than device size.

Then finally we goes "len = end - start + 1", totally underflow the
result, and lead to the beyond-device-boundary access.

[FIX]
This patch will fix the problem in two ways:

- Clear CHUNK_TRIMMED | CHUNK_ALLOCATED bits when shrinking device
  This is the root fix

- Add extra safety check when trimming free device extents
  We check and warn if the returned range is already beyond current
  device.

Link: https://github.com/kdave/btrfs-progs/issues/282
Fixes: 929be17a9b ("btrfs: Switch btrfs_trim_free_extents to find_first_clear_extent_bit")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-12 10:15:58 +02:00
Pavel Machek
881a3a11c2 btrfs: fix return value mixup in btrfs_get_extent
btrfs_get_extent() sets variable ret, but out: error path expect error
to be in variable err so the error code is lost.

Fixes: 6bf9e4bd6a ("btrfs: inode: Verify inode mode to avoid NULL pointer dereference")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-11 12:30:17 +02:00
Qu Wenruo
62ab2cc04d btrfs: sysfs: fix NULL pointer dereference at btrfs_sysfs_del_qgroups()
[BUG]
Unmounting a btrfs filesystem with quota disabled will cause the
following NULL pointer dereference:

  BTRFS info (device dm-5): has skinny extents
  BUG: kernel NULL pointer dereference, address: 0000000000000018
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  CPU: 7 PID: 637 Comm: umount Not tainted 5.8.0-rc7-next-20200731-custom #76
  RIP: 0010:kobject_del+0x6/0x20
  Call Trace:
   btrfs_sysfs_del_qgroups+0xac/0xf0 [btrfs]
   btrfs_free_qgroup_config+0x63/0x70 [btrfs]
   close_ctree+0x1f5/0x323 [btrfs]
   btrfs_put_super+0x15/0x17 [btrfs]
   generic_shutdown_super+0x72/0x110
   kill_anon_super+0x18/0x30
   btrfs_kill_super+0x17/0x30 [btrfs]
   deactivate_locked_super+0x3b/0xa0
   deactivate_super+0x40/0x50
   cleanup_mnt+0x135/0x190
   __cleanup_mnt+0x12/0x20
   task_work_run+0x64/0xb0
   exit_to_user_mode_prepare+0x18a/0x190
   syscall_exit_to_user_mode+0x4f/0x270
   do_syscall_64+0x45/0x50
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 37b7adca5c1d5c5d ]---

[CAUSE]
Commit 079ad2fb4b ("kobject: Avoid premature parent object freeing in
kobject_cleanup()") changed kobject_del() that it no longer accepts NULL
pointer.

Before that commit, kobject_del() and kobject_put() all accept NULL
pointers and just ignore such NULL pointers.

But that mentioned commit needs to access the parent node, killing the
old NULL pointer behavior.

Unfortunately btrfs is relying on that hidden feature thus we will
trigger such NULL pointer dereference.

[FIX]
Instead of just saving several lines, do proper fs_info->qgroups_kobj
check before calling kobject_del() and kobject_put().

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 19:51:08 +02:00
Boleyn Su
c15c2ec07a btrfs: check correct variable after allocation in btrfs_backref_iter_alloc
The `if (!ret)` check will always be false and it may result in
ret->path being dereferenced while it is a NULL pointer.

Fixes: a37f232b7b ("btrfs: backref: introduce the skeleton of btrfs_backref_iter")
CC: stable@vger.kernel.org # 5.8+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boleyn Su <boleynsu@google.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 19:50:54 +02:00
Josef Bacik
faa008899a btrfs: make sure SB_I_VERSION doesn't get unset by remount
There's some inconsistency around SB_I_VERSION handling with mount and
remount.  Since we don't really want it to be off ever just work around
this by making sure we don't get the flag cleared on remount.

There's a tiny cpu cost of setting the bit, otherwise all changes to
i_version also change some of the times (ctime/mtime) so the inode needs
to be synced. We wouldn't save anything by disabling it.

Reported-by: Eric Sandeen <sandeen@redhat.com>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add perf impact analysis ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:35 +02:00
Filipe Manana
4f26433e9b btrfs: fix memory leaks after failure to lookup checksums during inode logging
While logging an inode, at copy_items(), if we fail to lookup the checksums
for an extent we release the destination path, free the ins_data array and
then return immediately. However a previous iteration of the for loop may
have added checksums to the ordered_sums list, in which case we leak the
memory used by them.

So fix this by making sure we iterate the ordered_sums list and free all
its checksums before returning.

Fixes: 3650860b90 ("Btrfs: remove almost all of the BUG()'s from tree-log.c")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:30 +02:00
Josef Bacik
3ef3959b29 btrfs: don't show full path of bind mounts in subvol=
Chris Murphy reported a problem where rpm ostree will bind mount a bunch
of things for whatever voodoo it's doing.  But when it does this
/proc/mounts shows something like

  /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0
  /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo/bar 0 0

Despite subvolid=256 being subvol=/foo.  This is because we're just
spitting out the dentry of the mount point, which in the case of bind
mounts is the source path for the mountpoint.  Instead we should spit
out the path to the actual subvol.  Fix this by looking up the name for
the subvolid we have mounted.  With this fix the same test looks like
this

  /dev/sda /mnt/test btrfs rw,relatime,subvolid=256,subvol=/foo 0 0
  /dev/sda /mnt/test/baz btrfs rw,relatime,subvolid=256,subvol=/foo 0 0

Reported-by: Chris Murphy <chris@colorremedies.com>
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:26 +02:00
David Sterba
27942c9971 btrfs: fix messages after changing compression level by remount
Reported by Forza on IRC that remounting with compression options does
not reflect the change in level, or at least it does not appear to do so
according to the messages:

  mount -o compress=zstd:1 /dev/sda /mnt
  mount -o remount,compress=zstd:15 /mnt

does not print the change to the level to syslog:

  [   41.366060] BTRFS info (device vda): use zstd compression, level 1
  [   41.368254] BTRFS info (device vda): disk space caching is enabled
  [   41.390429] BTRFS info (device vda): disk space caching is enabled

What really happens is that the message is lost but the level is actualy
changed.

There's another weird output, if compression is reset to 'no':

  [   45.413776] BTRFS info (device vda): use no compression, level 4

To fix that, save the previous compression level and print the message
in that case too and use separate message for 'no' compression.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:16 +02:00
Josef Bacik
bf53d4687b btrfs: only search for left_info if there is no right_info in try_merge_free_space
In try_to_merge_free_space we attempt to find entries to the left and
right of the entry we are adding to see if they can be merged.  We
search for an entry past our current info (saved into right_info), and
then if right_info exists and it has a rb_prev() we save the rb_prev()
into left_info.

However there's a slight problem in the case that we have a right_info,
but no entry previous to that entry.  At that point we will search for
an entry just before the info we're attempting to insert.  This will
simply find right_info again, and assign it to left_info, making them
both the same pointer.

Now if right_info _can_ be merged with the range we're inserting, we'll
add it to the info and free right_info.  However further down we'll
access left_info, which was right_info, and thus get a use-after-free.

Fix this by only searching for the left entry if we don't find a right
entry at all.

The CVE referenced had a specially crafted file system that could
trigger this use-after-free. However with the tree checker improvements
we no longer trigger the conditions for the UAF.  But the original
conditions still apply, hence this fix.

Reference: CVE-2019-19448
Fixes: 9630308170 ("Btrfs: use hybrid extents+bitmap rb tree for free space")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:58:07 +02:00
Qu Wenruo
1e6e238c30 btrfs: inode: fix NULL pointer dereference if inode doesn't need compression
[BUG]
There is a bug report of NULL pointer dereference caused in
compress_file_extent():

  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  Workqueue: btrfs-delalloc btrfs_delalloc_helper [btrfs]
  NIP [c008000006dd4d34] compress_file_range.constprop.41+0x75c/0x8a0 [btrfs]
  LR [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs]
  Call Trace:
  [c000000c69093b00] [c008000006dd4d1c] compress_file_range.constprop.41+0x744/0x8a0 [btrfs] (unreliable)
  [c000000c69093bd0] [c008000006dd4ebc] async_cow_start+0x44/0xa0 [btrfs]
  [c000000c69093c10] [c008000006e14824] normal_work_helper+0xdc/0x598 [btrfs]
  [c000000c69093c80] [c0000000001608c0] process_one_work+0x2c0/0x5b0
  [c000000c69093d10] [c000000000160c38] worker_thread+0x88/0x660
  [c000000c69093db0] [c00000000016b55c] kthread+0x1ac/0x1c0
  [c000000c69093e20] [c00000000000b660] ret_from_kernel_thread+0x5c/0x7c
  ---[ end trace f16954aa20d822f6 ]---

[CAUSE]
For the following execution route of compress_file_range(), it's
possible to hit NULL pointer dereference:

 compress_file_extent()
 |- pages = NULL;
 |- start = async_chunk->start = 0;
 |- end = async_chunk = 4095;
 |- nr_pages = 1;
 |- inode_need_compress() == false; <<< Possible, see later explanation
 |  Now, we have nr_pages = 1, pages = NULL
 |- cont:
 |- 		ret = cow_file_range_inline();
 |- 		if (ret <= 0) {
 |-		for (i = 0; i < nr_pages; i++) {
 |-			WARN_ON(pages[i]->mapping);	<<< Crash

To enter above call execution branch, we need the following race:

    Thread 1 (chattr)     |            Thread 2 (writeback)
--------------------------+------------------------------
                          | btrfs_run_delalloc_range
                          | |- inode_need_compress = true
                          | |- cow_file_range_async()
btrfs_ioctl_set_flag()    |
|- binode_flags |=        |
   BTRFS_INODE_NOCOMPRESS |
                          | compress_file_range()
                          | |- inode_need_compress = false
                          | |- nr_page = 1 while pages = NULL
                          | |  Then hit the crash

[FIX]
This patch will fix it by checking @pages before doing accessing it.
This patch is only designed as a hot fix and easy to backport.

More elegant fix may make btrfs only check inode_need_compress() once to
avoid such race, but that would be another story.

Reported-by: Luciano Chavez <chavez@us.ibm.com>
Fixes: 4d3a800ebb ("btrfs: merge nr_pages input and output parameter in compress_pages")
CC: stable@vger.kernel.org # 4.14.x: cecc8d9038: btrfs: Move free_pages_out label in inline extent handling branch in compress_file_range
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-08-10 18:57:59 +02:00
Linus Torvalds
b79675e15a Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "No common topic whatsoever in those, sorry"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: define inode flags using bit numbers
  iov_iter: Move unnecessary inclusion of crypto/hash.h
  dlmfs: clean up dlmfs_file_{read,write}() a bit
2020-08-07 21:14:30 -07:00
Linus Torvalds
8f0cb6660a These are the latest RCU bits for v5.9:
- kfree_rcu updates
   - RCU tasks updates
   - Read-side scalability tests
   - SRCU updates
   - Torture-test updates
   - Documentation updates
   - Miscellaneous fixes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - kfree_rcu updates

 - RCU tasks updates

 - Read-side scalability tests

 - SRCU updates

 - Torture-test updates

 - Documentation updates

 - Miscellaneous fixes

* tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (109 commits)
  torture: Remove obsolete "cd $KVM"
  torture: Avoid duplicate specification of qemu command
  torture: Dump ftrace at shutdown only if requested
  torture: Add kvm-tranform.sh script for qemu-cmd files
  torture: Add more tracing crib notes to kvm.sh
  torture: Improve diagnostic for KCSAN-incapable compilers
  torture: Correctly summarize build-only runs
  torture: Pass --kmake-arg to all make invocations
  rcutorture: Check for unwatched readers
  torture: Abstract out console-log error detection
  torture: Add a stop-run capability
  torture: Create qemu-cmd in --buildonly runs
  rcu/rcutorture: Replace 0 with false
  torture: Add --allcpus argument to the kvm.sh script
  torture: Remove whitespace from identify_qemu_vcpus output
  rcutorture: NULL rcu_torture_current earlier in cleanup code
  rcutorture: Handle non-statistic bang-string error messages
  torture: Set configfile variable to current scenario
  rcutorture: Add races with task-exit processing
  locktorture: Use true and false to assign to bool variables
  ...
2020-08-03 14:31:33 -07:00
Linus Torvalds
cdc8fcb499 for-5.9/io_uring-20200802
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Merge tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Lots of cleanups in here, hardening the code and/or making it easier
  to read and fixing bugs, but a core feature/change too adding support
  for real async buffered reads. With the latter in place, we just need
  buffered write async support and we're done relying on kthreads for
  the fast path. In detail:

   - Cleanup how memory accounting is done on ring setup/free (Bijan)

   - sq array offset calculation fixup (Dmitry)

   - Consistently handle blocking off O_DIRECT submission path (me)

   - Support proper async buffered reads, instead of relying on kthread
     offload for that. This uses the page waitqueue to drive retries
     from task_work, like we handle poll based retry. (me)

   - IO completion optimizations (me)

   - Fix race with accounting and ring fd install (me)

   - Support EPOLLEXCLUSIVE (Jiufei)

   - Get rid of the io_kiocb unionizing, made possible by shrinking
     other bits (Pavel)

   - Completion side cleanups (Pavel)

   - Cleanup REQ_F_ flags handling, and kill off many of them (Pavel)

   - Request environment grabbing cleanups (Pavel)

   - File and socket read/write cleanups (Pavel)

   - Improve kiocb_set_rw_flags() (Pavel)

   - Tons of fixes and cleanups (Pavel)

   - IORING_SQ_NEED_WAKEUP clear fix (Xiaoguang)"

* tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block: (127 commits)
  io_uring: flip if handling after io_setup_async_rw
  fs: optimise kiocb_set_rw_flags()
  io_uring: don't touch 'ctx' after installing file descriptor
  io_uring: get rid of atomic FAA for cq_timeouts
  io_uring: consolidate *_check_overflow accounting
  io_uring: fix stalled deferred requests
  io_uring: fix racy overflow count reporting
  io_uring: deduplicate __io_complete_rw()
  io_uring: de-unionise io_kiocb
  io-wq: update hash bits
  io_uring: fix missing io_queue_linked_timeout()
  io_uring: mark ->work uninitialised after cleanup
  io_uring: deduplicate io_grab_files() calls
  io_uring: don't do opcode prep twice
  io_uring: clear IORING_SQ_NEED_WAKEUP after executing task works
  io_uring: batch put_task_struct()
  tasks: add put_task_struct_many()
  io_uring: return locked and pinned page accounting
  io_uring: don't miscount pinned memory
  io_uring: don't open-code recv kbuf managment
  ...
2020-08-03 13:01:22 -07:00
Linus Torvalds
382625d0d4 for-5.9/block-20200802
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Merge tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block

Pull core block updates from Jens Axboe:
 "Good amount of cleanups and tech debt removals in here, and as a
  result, the diffstat shows a nice net reduction in code.

   - Softirq completion cleanups (Christoph)

   - Stop using ->queuedata (Christoph)

   - Cleanup bd claiming (Christoph)

   - Use check_events, moving away from the legacy media change
     (Christoph)

   - Use inode i_blkbits consistently (Christoph)

   - Remove old unused writeback congestion bits (Christoph)

   - Cleanup/unify submission path (Christoph)

   - Use bio_uninit consistently, instead of bio_disassociate_blkg
     (Christoph)

   - sbitmap cleared bits handling (John)

   - Request merging blktrace event addition (Jan)

   - sysfs add/remove race fixes (Luis)

   - blk-mq tag fixes/optimizations (Ming)

   - Duplicate words in comments (Randy)

   - Flush deferral cleanup (Yufen)

   - IO context locking/retry fixes (John)

   - struct_size() usage (Gustavo)

   - blk-iocost fixes (Chengming)

   - blk-cgroup IO stats fixes (Boris)

   - Various little fixes"

* tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block: (135 commits)
  block: blk-timeout: delete duplicated word
  block: blk-mq-sched: delete duplicated word
  block: blk-mq: delete duplicated word
  block: genhd: delete duplicated words
  block: elevator: delete duplicated word and fix typos
  block: bio: delete duplicated words
  block: bfq-iosched: fix duplicated word
  iocost_monitor: start from the oldest usage index
  iocost: Fix check condition of iocg abs_vdebt
  block: Remove callback typedefs for blk_mq_ops
  block: Use non _rcu version of list functions for tag_set_list
  blk-cgroup: show global disk stats in root cgroup io.stat
  blk-cgroup: make iostat functions visible to stat printing
  block: improve discard bio alignment in __blkdev_issue_discard()
  block: change REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL to be odd numbers
  block: defer flush request no matter whether we have elevator
  block: make blk_timeout_init() static
  block: remove retry loop in ioc_release_fn()
  block: remove unnecessary ioc nested locking
  block: integrate bd_start_claiming into __blkdev_get
  ...
2020-08-03 11:57:03 -07:00
Ingo Molnar
c1cc4784ce Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull the v5.9 RCU bits from Paul E. McKenney:

 - Documentation updates
 - Miscellaneous fixes
 - kfree_rcu updates
 - RCU tasks updates
 - Read-side scalability tests
 - SRCU updates
 - Torture-test updates

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-07-31 00:15:53 +02:00
Filipe Manana
5e548b3201 btrfs: do not set the full sync flag on the inode during page release
When removing an extent map at try_release_extent_mapping(), called through
the page release callback (btrfs_releasepage()), we always set the full
sync flag on the inode, which forces the next fsync to use a slower code
path.

This hurts performance for workloads that dirty an amount of data that
exceeds or is very close to the system's RAM memory and do frequent fsync
operations (like database servers can for example). In particular if there
are concurrent fsyncs against different files, by falling back to a full
fsync we do a lot more checksum lookups in the checksums btree, as we do
it for all the extents created in the current transaction, instead of only
the new ones since the last fsync. These checksums lookups not only take
some time but, more importantly, they also cause contention on the
checksums btree locks due to the concurrency with checksum insertions in
the btree by ordered extents from other inodes.

We actually don't need to set the full sync flag on the inode, because we
only remove extent maps that are in the list of modified extents if they
were created in a past transaction, in which case an fsync skips them as
it's pointless to log them. So stop setting the full fsync flag on the
inode whenever we remove an extent map.

This patch is part of a patchset that consists of 3 patches, which have
the following subjects:

1/3 btrfs: fix race between page release and a fast fsync
2/3 btrfs: release old extent maps during page release
3/3 btrfs: do not set the full sync flag on the inode during page release

Performance tests were ran against a branch (misc-next) containing the
whole patchset. The test exercises a workload where there are multiple
processes writing to files and fsyncing them (each writing and fsyncing
its own file), and in total the amount of data dirtied ranges from 2x to
4x the system's RAM memory (16GiB), so that the page release callback is
invoked frequently.

The following script, using fio, was used to perform the tests:

  $ cat test-fsync.sh
  #!/bin/bash

  DEV=/dev/sdk
  MNT=/mnt/sdk
  MOUNT_OPTIONS="-o ssd"
  MKFS_OPTIONS="-d single -m single"

  if [ $# -ne 3 ]; then
      echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ"
      exit 1
  fi

  NUM_JOBS=$1
  FILE_SIZE=$2
  FSYNC_FREQ=$3

  cat <<EOF > /tmp/fio-job.ini
  [writers]
  rw=write
  fsync=$FSYNC_FREQ
  fallocate=none
  group_reporting=1
  direct=0
  bs=64k
  ioengine=sync
  size=$FILE_SIZE
  directory=$MNT
  numjobs=$NUM_JOBS
  thread
  EOF

  echo "Using config:"
  echo
  cat /tmp/fio-job.ini
  echo

  mkfs.btrfs -f $MKFS_OPTIONS $DEV &> /dev/null
  mount $MOUNT_OPTIONS $DEV $MNT
  fio /tmp/fio-job.ini
  umount $MNT

The tests were performed for different numbers of jobs, file sizes and
fsync frequency. A qemu VM using kvm was used, with 8 cores (the host has
12 cores, with cpu governance set to performance mode on all cores), 16GiB
of ram (the host has 64GiB) and using a NVMe device directly (without an
intermediary filesystem in the host). While running the tests, the host
was not used for anything else, to avoid disturbing the tests.

The obtained results were the following, and the last line printed by
fio is pasted (includes aggregated throughput and test run time).

    *****************************************************
    ****     1 job, 32GiB file, fsync frequency 1     ****
    *****************************************************

Before patchset:

WRITE: bw=29.1MiB/s (30.5MB/s), 29.1MiB/s-29.1MiB/s (30.5MB/s-30.5MB/s), io=32.0GiB (34.4GB), run=1127557-1127557msec

After patchset:

WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=32.0GiB (34.4GB), run=1119042-1119042msec
(+0.7% throughput, -0.8% run time)

    *****************************************************
    ****     2 jobs, 16GiB files, fsync frequency 1   ****
    *****************************************************

Before patchset:

WRITE: bw=33.5MiB/s (35.1MB/s), 33.5MiB/s-33.5MiB/s (35.1MB/s-35.1MB/s), io=32.0GiB (34.4GB), run=979000-979000msec

After patchset:

WRITE: bw=39.9MiB/s (41.8MB/s), 39.9MiB/s-39.9MiB/s (41.8MB/s-41.8MB/s), io=32.0GiB (34.4GB), run=821283-821283msec
(+19.1% throughput, -16.1% runtime)

    *****************************************************
    ****     4 jobs, 8GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=52.1MiB/s (54.6MB/s), 52.1MiB/s-52.1MiB/s (54.6MB/s-54.6MB/s), io=32.0GiB (34.4GB), run=629130-629130msec

After patchset:

WRITE: bw=71.8MiB/s (75.3MB/s), 71.8MiB/s-71.8MiB/s (75.3MB/s-75.3MB/s), io=32.0GiB (34.4GB), run=456357-456357msec
(+37.8% throughput, -27.5% runtime)

    *****************************************************
    ****     8 jobs, 4GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=76.1MiB/s (79.8MB/s), 76.1MiB/s-76.1MiB/s (79.8MB/s-79.8MB/s), io=32.0GiB (34.4GB), run=430708-430708msec

After patchset:

WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=245458-245458msec
(+74.7% throughput, -43.0% run time)

    *****************************************************
    ****    16 jobs, 2GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=74.7MiB/s (78.3MB/s), 74.7MiB/s-74.7MiB/s (78.3MB/s-78.3MB/s), io=32.0GiB (34.4GB), run=438625-438625msec

After patchset:

WRITE: bw=184MiB/s (193MB/s), 184MiB/s-184MiB/s (193MB/s-193MB/s), io=32.0GiB (34.4GB), run=177864-177864msec
(+146.3% throughput, -59.5% run time)

    *****************************************************
    ****    32 jobs, 2GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=72.6MiB/s (76.1MB/s), 72.6MiB/s-72.6MiB/s (76.1MB/s-76.1MB/s), io=64.0GiB (68.7GB), run=902615-902615msec

After patchset:

WRITE: bw=227MiB/s (238MB/s), 227MiB/s-227MiB/s (238MB/s-238MB/s), io=64.0GiB (68.7GB), run=288936-288936msec
(+212.7% throughput, -68.0% run time)

    *****************************************************
    ****    64 jobs, 1GiB files, fsync frequency 1    ****
    *****************************************************

Before patchset:

WRITE: bw=98.8MiB/s (104MB/s), 98.8MiB/s-98.8MiB/s (104MB/s-104MB/s), io=64.0GiB (68.7GB), run=663126-663126msec

After patchset:

WRITE: bw=294MiB/s (308MB/s), 294MiB/s-294MiB/s (308MB/s-308MB/s), io=64.0GiB (68.7GB), run=222940-222940msec
(+197.6% throughput, -66.4% run time)

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:48 +02:00
Filipe Manana
fbc2bd7e7a btrfs: release old extent maps during page release
When removing an extent map at try_release_extent_mapping(), called through
the page release callback (btrfs_releasepage()), we never release an extent
map that is in the list of modified extents. This is to prevent races with
a concurrent fsync using the fast path, which could lead to not logging an
extent created in the current transaction.

However we can safely remove an extent map created in a past transaction
that is still in the list of modified extents (because no one fsynced yet
the inode after that transaction got commited), because such extents are
skipped during an fsync as it is pointless to log them. This change does
that.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:48 +02:00
Filipe Manana
3d6448e631 btrfs: fix race between page release and a fast fsync
When releasing an extent map, done through the page release callback, we
can race with an ongoing fast fsync and cause the fsync to miss a new
extent and not log it. The steps for this to happen are the following:

1) A page is dirtied for some inode I;

2) Writeback for that page is triggered by a path other than fsync, for
   example by the system due to memory pressure;

3) When the ordered extent for the extent (a single 4K page) finishes,
   we unpin the corresponding extent map and set its generation to N,
   the current transaction's generation;

4) The btrfs_releasepage() callback is invoked by the system due to
   memory pressure for that no longer dirty page of inode I;

5) At the same time, some task calls fsync on inode I, joins transaction
   N, and at btrfs_log_inode() it sees that the inode does not have the
   full sync flag set, so we proceed with a fast fsync. But before we get
   into btrfs_log_changed_extents() and lock the inode's extent map tree:

6) Through btrfs_releasepage() we end up at try_release_extent_mapping()
   and we remove the extent map for the new 4Kb extent, because it is
   neither pinned anymore nor locked. By calling remove_extent_mapping(),
   we remove the extent map from the list of modified extents, since the
   extent map does not have the logging flag set. We unlock the inode's
   extent map tree;

7) The task doing the fast fsync now enters btrfs_log_changed_extents(),
   locks the inode's extent map tree and iterates its list of modified
   extents, which no longer has the 4Kb extent in it, so it does not log
   the extent;

8) The fsync finishes;

9) Before transaction N is committed, a power failure happens. After
   replaying the log, the 4K extent of inode I will be missing, since
   it was not logged due to the race with try_release_extent_mapping().

So fix this by teaching try_release_extent_mapping() to not remove an
extent map if it's still in the list of modified extents.

Fixes: ff44c6e36d ("Btrfs: do not hold the write_lock on the extent tree while logging")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00
Johannes Thumshirn
88c4703f00 btrfs: open-code remount flag setting in btrfs_remount
When we're (re)mounting a btrfs filesystem we set the
BTRFS_FS_STATE_REMOUNTING state in fs_info to serialize against async
reclaim or defrags.

This flag is set in btrfs_remount_prepare() called by btrfs_remount().
As btrfs_remount_prepare() does nothing but setting this flag and
doesn't have a second caller, we can just open-code the flag setting in
btrfs_remount().

Similarly do for so clearing of the flag by moving it out of
btrfs_remount_cleanup() into btrfs_remount() to be symmetrical.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00
Josef Bacik
162e0a16b7 btrfs: if we're restriping, use the target restripe profile
Previously we depended on some weird behavior in our chunk allocator to
force the allocation of new stripes, so by the time we got to doing the
reduce we would usually already have a chunk with the proper target.

However that behavior causes other problems and needs to be removed.
First however we need to remove this check to only restripe if we
already have those available profiles, because if we're allocating our
first chunk it obviously will not be available.  Simply use the target
as specified, and if that fails it'll be because we're out of space.

Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00
Josef Bacik
349e120ece btrfs: don't adjust bg flags and use default allocation profiles
btrfs/061 has been failing consistently for me recently with a
transaction abort.  We run out of space in the system chunk array, which
means we've allocated way too many system chunks than we need.

Chris added this a long time ago for balance as a poor mans restriping.
If you had a single disk and then added another disk and then did a
balance, update_block_group_flags would then figure out which RAID level
you needed.

Fast forward to today and we have restriping behavior, so we can
explicitly tell the fs that we're trying to change the raid level.  This
is accomplished through the normal get_alloc_profile path.

Furthermore this code actually causes btrfs/061 to fail, because we do
things like mkfs -m dup -d single with multiple devices.  This trips
this check

alloc_flags = update_block_group_flags(fs_info, cache->flags);
if (alloc_flags != cache->flags) {
	ret = btrfs_chunk_alloc(trans, alloc_flags, CHUNK_ALLOC_FORCE);

in btrfs_inc_block_group_ro.  Because we're balancing and scrubbing, but
not actually restriping, we keep forcing chunk allocation of RAID1
chunks.  This eventually causes us to run out of system space and the
file system aborts and flips read only.

We don't need this poor mans restriping any more, simply use the normal
get_alloc_profile helper, which will get the correct alloc_flags and
thus make the right decision for chunk allocation.  This keeps us from
allocating a billion system chunks and falling over.

Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00
Josef Bacik
ab0db043c3 btrfs: fix lockdep splat from btrfs_dump_space_info
When running with -o enospc_debug you can get the following splat if one
of the dump_space_info's trip

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc5+ #20 Tainted: G           OE
  ------------------------------------------------------
  dd/563090 is trying to acquire lock:
  ffff9e7dbf4f1e18 (&ctl->tree_lock){+.+.}-{2:2}, at: btrfs_dump_free_space+0x2b/0xa0 [btrfs]

  but task is already holding lock:
  ffff9e7e2284d428 (&cache->lock){+.+.}-{2:2}, at: btrfs_dump_space_info+0xaa/0x120 [btrfs]

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&cache->lock){+.+.}-{2:2}:
	 _raw_spin_lock+0x25/0x30
	 btrfs_add_reserved_bytes+0x3c/0x3c0 [btrfs]
	 find_free_extent+0x7ef/0x13b0 [btrfs]
	 btrfs_reserve_extent+0x9b/0x180 [btrfs]
	 btrfs_alloc_tree_block+0xc1/0x340 [btrfs]
	 alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs]
	 __btrfs_cow_block+0x122/0x530 [btrfs]
	 btrfs_cow_block+0x106/0x210 [btrfs]
	 commit_cowonly_roots+0x55/0x300 [btrfs]
	 btrfs_commit_transaction+0x4ed/0xac0 [btrfs]
	 sync_filesystem+0x74/0x90
	 generic_shutdown_super+0x22/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20 [btrfs]
	 deactivate_locked_super+0x36/0x70
	 cleanup_mnt+0x104/0x160
	 task_work_run+0x5f/0x90
	 __prepare_exit_to_usermode+0x1bd/0x1c0
	 do_syscall_64+0x5e/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #2 (&space_info->lock){+.+.}-{2:2}:
	 _raw_spin_lock+0x25/0x30
	 btrfs_block_rsv_release+0x1a6/0x3f0 [btrfs]
	 btrfs_inode_rsv_release+0x4f/0x170 [btrfs]
	 btrfs_clear_delalloc_extent+0x155/0x480 [btrfs]
	 clear_state_bit+0x81/0x1a0 [btrfs]
	 __clear_extent_bit+0x25c/0x5d0 [btrfs]
	 clear_extent_bit+0x15/0x20 [btrfs]
	 btrfs_invalidatepage+0x2b7/0x3c0 [btrfs]
	 truncate_cleanup_page+0x47/0xe0
	 truncate_inode_pages_range+0x238/0x840
	 truncate_pagecache+0x44/0x60
	 btrfs_setattr+0x202/0x5e0 [btrfs]
	 notify_change+0x33b/0x490
	 do_truncate+0x76/0xd0
	 path_openat+0x687/0xa10
	 do_filp_open+0x91/0x100
	 do_sys_openat2+0x215/0x2d0
	 do_sys_open+0x44/0x80
	 do_syscall_64+0x52/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&tree->lock#2){+.+.}-{2:2}:
	 _raw_spin_lock+0x25/0x30
	 find_first_extent_bit+0x32/0x150 [btrfs]
	 write_pinned_extent_entries.isra.0+0xc5/0x100 [btrfs]
	 __btrfs_write_out_cache+0x172/0x480 [btrfs]
	 btrfs_write_out_cache+0x7a/0xf0 [btrfs]
	 btrfs_write_dirty_block_groups+0x286/0x3b0 [btrfs]
	 commit_cowonly_roots+0x245/0x300 [btrfs]
	 btrfs_commit_transaction+0x4ed/0xac0 [btrfs]
	 close_ctree+0xf9/0x2f5 [btrfs]
	 generic_shutdown_super+0x6c/0x100
	 kill_anon_super+0x14/0x30
	 btrfs_kill_super+0x12/0x20 [btrfs]
	 deactivate_locked_super+0x36/0x70
	 cleanup_mnt+0x104/0x160
	 task_work_run+0x5f/0x90
	 __prepare_exit_to_usermode+0x1bd/0x1c0
	 do_syscall_64+0x5e/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&ctl->tree_lock){+.+.}-{2:2}:
	 __lock_acquire+0x1240/0x2460
	 lock_acquire+0xab/0x360
	 _raw_spin_lock+0x25/0x30
	 btrfs_dump_free_space+0x2b/0xa0 [btrfs]
	 btrfs_dump_space_info+0xf4/0x120 [btrfs]
	 btrfs_reserve_extent+0x176/0x180 [btrfs]
	 __btrfs_prealloc_file_range+0x145/0x550 [btrfs]
	 cache_save_setup+0x28d/0x3b0 [btrfs]
	 btrfs_start_dirty_block_groups+0x1fc/0x4f0 [btrfs]
	 btrfs_commit_transaction+0xcc/0xac0 [btrfs]
	 btrfs_alloc_data_chunk_ondemand+0x162/0x4c0 [btrfs]
	 btrfs_check_data_free_space+0x4c/0xa0 [btrfs]
	 btrfs_buffered_write.isra.0+0x19b/0x740 [btrfs]
	 btrfs_file_write_iter+0x3cf/0x610 [btrfs]
	 new_sync_write+0x11e/0x1b0
	 vfs_write+0x1c9/0x200
	 ksys_write+0x68/0xe0
	 do_syscall_64+0x52/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

  Chain exists of:
    &ctl->tree_lock --> &space_info->lock --> &cache->lock

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&cache->lock);
				 lock(&space_info->lock);
				 lock(&cache->lock);
    lock(&ctl->tree_lock);

   *** DEADLOCK ***

  6 locks held by dd/563090:
   #0: ffff9e7e21d18448 (sb_writers#14){.+.+}-{0:0}, at: vfs_write+0x195/0x200
   #1: ffff9e7dd0410ed8 (&sb->s_type->i_mutex_key#19){++++}-{3:3}, at: btrfs_file_write_iter+0x86/0x610 [btrfs]
   #2: ffff9e7e21d18638 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x40b/0x5b0 [btrfs]
   #3: ffff9e7e1f05d688 (&cur_trans->cache_write_mutex){+.+.}-{3:3}, at: btrfs_start_dirty_block_groups+0x158/0x4f0 [btrfs]
   #4: ffff9e7e2284ddb8 (&space_info->groups_sem){++++}-{3:3}, at: btrfs_dump_space_info+0x69/0x120 [btrfs]
   #5: ffff9e7e2284d428 (&cache->lock){+.+.}-{2:2}, at: btrfs_dump_space_info+0xaa/0x120 [btrfs]

  stack backtrace:
  CPU: 3 PID: 563090 Comm: dd Tainted: G           OE     5.8.0-rc5+ #20
  Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./890FX Deluxe5, BIOS P1.40 05/03/2011
  Call Trace:
   dump_stack+0x96/0xd0
   check_noncircular+0x162/0x180
   __lock_acquire+0x1240/0x2460
   ? wake_up_klogd.part.0+0x30/0x40
   lock_acquire+0xab/0x360
   ? btrfs_dump_free_space+0x2b/0xa0 [btrfs]
   _raw_spin_lock+0x25/0x30
   ? btrfs_dump_free_space+0x2b/0xa0 [btrfs]
   btrfs_dump_free_space+0x2b/0xa0 [btrfs]
   btrfs_dump_space_info+0xf4/0x120 [btrfs]
   btrfs_reserve_extent+0x176/0x180 [btrfs]
   __btrfs_prealloc_file_range+0x145/0x550 [btrfs]
   ? btrfs_qgroup_reserve_data+0x1d/0x60 [btrfs]
   cache_save_setup+0x28d/0x3b0 [btrfs]
   btrfs_start_dirty_block_groups+0x1fc/0x4f0 [btrfs]
   btrfs_commit_transaction+0xcc/0xac0 [btrfs]
   ? start_transaction+0xe0/0x5b0 [btrfs]
   btrfs_alloc_data_chunk_ondemand+0x162/0x4c0 [btrfs]
   btrfs_check_data_free_space+0x4c/0xa0 [btrfs]
   btrfs_buffered_write.isra.0+0x19b/0x740 [btrfs]
   ? ktime_get_coarse_real_ts64+0xa8/0xd0
   ? trace_hardirqs_on+0x1c/0xe0
   btrfs_file_write_iter+0x3cf/0x610 [btrfs]
   new_sync_write+0x11e/0x1b0
   vfs_write+0x1c9/0x200
   ksys_write+0x68/0xe0
   do_syscall_64+0x52/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This is because we're holding the block_group->lock while trying to dump
the free space cache.  However we don't need this lock, we just need it
to read the values for the printk, so move the free space cache dumping
outside of the block group lock.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:47 +02:00
Josef Bacik
01d01caf19 btrfs: move the chunk_mutex in btrfs_read_chunk_tree
We are currently getting this lockdep splat in btrfs/161:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc5+ #20 Tainted: G            E
  ------------------------------------------------------
  mount/678048 is trying to acquire lock:
  ffff9b769f15b6e0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: clone_fs_devices+0x4d/0x170 [btrfs]

  but task is already holding lock:
  ffff9b76abdb08d0 (&fs_info->chunk_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x6a/0x800 [btrfs]

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
	 __mutex_lock+0x8b/0x8f0
	 btrfs_init_new_device+0x2d2/0x1240 [btrfs]
	 btrfs_ioctl+0x1de/0x2d20 [btrfs]
	 ksys_ioctl+0x87/0xc0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x52/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #0 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
	 __lock_acquire+0x1240/0x2460
	 lock_acquire+0xab/0x360
	 __mutex_lock+0x8b/0x8f0
	 clone_fs_devices+0x4d/0x170 [btrfs]
	 btrfs_read_chunk_tree+0x330/0x800 [btrfs]
	 open_ctree+0xb7c/0x18ce [btrfs]
	 btrfs_mount_root.cold+0x13/0xfa [btrfs]
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 fc_mount+0xe/0x40
	 vfs_kern_mount.part.0+0x71/0x90
	 btrfs_mount+0x13b/0x3e0 [btrfs]
	 legacy_get_tree+0x30/0x50
	 vfs_get_tree+0x28/0xc0
	 do_mount+0x7de/0xb30
	 __x64_sys_mount+0x8e/0xd0
	 do_syscall_64+0x52/0xb0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  other info that might help us debug this:

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(&fs_info->chunk_mutex);
				 lock(&fs_devs->device_list_mutex);
				 lock(&fs_info->chunk_mutex);
    lock(&fs_devs->device_list_mutex);

   *** DEADLOCK ***

  3 locks held by mount/678048:
   #0: ffff9b75ff5fb0e0 (&type->s_umount_key#63/1){+.+.}-{3:3}, at: alloc_super+0xb5/0x380
   #1: ffffffffc0c2fbc8 (uuid_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x54/0x800 [btrfs]
   #2: ffff9b76abdb08d0 (&fs_info->chunk_mutex){+.+.}-{3:3}, at: btrfs_read_chunk_tree+0x6a/0x800 [btrfs]

  stack backtrace:
  CPU: 2 PID: 678048 Comm: mount Tainted: G            E     5.8.0-rc5+ #20
  Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./890FX Deluxe5, BIOS P1.40 05/03/2011
  Call Trace:
   dump_stack+0x96/0xd0
   check_noncircular+0x162/0x180
   __lock_acquire+0x1240/0x2460
   ? asm_sysvec_apic_timer_interrupt+0x12/0x20
   lock_acquire+0xab/0x360
   ? clone_fs_devices+0x4d/0x170 [btrfs]
   __mutex_lock+0x8b/0x8f0
   ? clone_fs_devices+0x4d/0x170 [btrfs]
   ? rcu_read_lock_sched_held+0x52/0x60
   ? cpumask_next+0x16/0x20
   ? module_assert_mutex_or_preempt+0x14/0x40
   ? __module_address+0x28/0xf0
   ? clone_fs_devices+0x4d/0x170 [btrfs]
   ? static_obj+0x4f/0x60
   ? lockdep_init_map_waits+0x43/0x200
   ? clone_fs_devices+0x4d/0x170 [btrfs]
   clone_fs_devices+0x4d/0x170 [btrfs]
   btrfs_read_chunk_tree+0x330/0x800 [btrfs]
   open_ctree+0xb7c/0x18ce [btrfs]
   ? super_setup_bdi_name+0x79/0xd0
   btrfs_mount_root.cold+0x13/0xfa [btrfs]
   ? vfs_parse_fs_string+0x84/0xb0
   ? rcu_read_lock_sched_held+0x52/0x60
   ? kfree+0x2b5/0x310
   legacy_get_tree+0x30/0x50
   vfs_get_tree+0x28/0xc0
   fc_mount+0xe/0x40
   vfs_kern_mount.part.0+0x71/0x90
   btrfs_mount+0x13b/0x3e0 [btrfs]
   ? cred_has_capability+0x7c/0x120
   ? rcu_read_lock_sched_held+0x52/0x60
   ? legacy_get_tree+0x30/0x50
   legacy_get_tree+0x30/0x50
   vfs_get_tree+0x28/0xc0
   do_mount+0x7de/0xb30
   ? memdup_user+0x4e/0x90
   __x64_sys_mount+0x8e/0xd0
   do_syscall_64+0x52/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This is because btrfs_read_chunk_tree() can come upon DEV_EXTENT's and
then read the device, which takes the device_list_mutex.  The
device_list_mutex needs to be taken before the chunk_mutex, so this is a
problem.  We only really need the chunk mutex around adding the chunk,
so move the mutex around read_one_chunk.

An argument could be made that we don't even need the chunk_mutex here
as it's during mount, and we are protected by various other locks.
However we already have special rules for ->device_list_mutex, and I'd
rather not have another special case for ->chunk_mutex.

CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:46 +02:00
Josef Bacik
18c850fdc5 btrfs: open device without device_list_mutex
There's long existed a lockdep splat because we open our bdev's under
the ->device_list_mutex at mount time, which acquires the bd_mutex.
Usually this goes unnoticed, but if you do loopback devices at all
suddenly the bd_mutex comes with a whole host of other dependencies,
which results in the splat when you mount a btrfs file system.

======================================================
WARNING: possible circular locking dependency detected
5.8.0-0.rc3.1.fc33.x86_64+debug #1 Not tainted
------------------------------------------------------
systemd-journal/509 is trying to acquire lock:
ffff970831f84db0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x44/0x70 [btrfs]

but task is already holding lock:
ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

 -> #6 (sb_pagefaults){.+.+}-{0:0}:
       __sb_start_write+0x13e/0x220
       btrfs_page_mkwrite+0x59/0x560 [btrfs]
       do_page_mkwrite+0x4f/0x130
       do_wp_page+0x3b0/0x4f0
       handle_mm_fault+0xf47/0x1850
       do_user_addr_fault+0x1fc/0x4b0
       exc_page_fault+0x88/0x300
       asm_exc_page_fault+0x1e/0x30

 -> #5 (&mm->mmap_lock#2){++++}-{3:3}:
       __might_fault+0x60/0x80
       _copy_from_user+0x20/0xb0
       get_sg_io_hdr+0x9a/0xb0
       scsi_cmd_ioctl+0x1ea/0x2f0
       cdrom_ioctl+0x3c/0x12b4
       sr_block_ioctl+0xa4/0xd0
       block_ioctl+0x3f/0x50
       ksys_ioctl+0x82/0xc0
       __x64_sys_ioctl+0x16/0x20
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #4 (&cd->lock){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       sr_block_open+0xa2/0x180
       __blkdev_get+0xdd/0x550
       blkdev_get+0x38/0x150
       do_dentry_open+0x16b/0x3e0
       path_openat+0x3c9/0xa00
       do_filp_open+0x75/0x100
       do_sys_openat2+0x8a/0x140
       __x64_sys_openat+0x46/0x70
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #3 (&bdev->bd_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       __blkdev_get+0x6a/0x550
       blkdev_get+0x85/0x150
       blkdev_get_by_path+0x2c/0x70
       btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs]
       open_fs_devices+0x88/0x240 [btrfs]
       btrfs_open_devices+0x92/0xa0 [btrfs]
       btrfs_mount_root+0x250/0x490 [btrfs]
       legacy_get_tree+0x30/0x50
       vfs_get_tree+0x28/0xc0
       vfs_kern_mount.part.0+0x71/0xb0
       btrfs_mount+0x119/0x380 [btrfs]
       legacy_get_tree+0x30/0x50
       vfs_get_tree+0x28/0xc0
       do_mount+0x8c6/0xca0
       __x64_sys_mount+0x8e/0xd0
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       btrfs_run_dev_stats+0x36/0x420 [btrfs]
       commit_cowonly_roots+0x91/0x2d0 [btrfs]
       btrfs_commit_transaction+0x4e6/0x9f0 [btrfs]
       btrfs_sync_file+0x38a/0x480 [btrfs]
       __x64_sys_fdatasync+0x47/0x80
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}:
       __mutex_lock+0x7b/0x820
       btrfs_commit_transaction+0x48e/0x9f0 [btrfs]
       btrfs_sync_file+0x38a/0x480 [btrfs]
       __x64_sys_fdatasync+0x47/0x80
       do_syscall_64+0x52/0xb0
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

 -> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}:
       __lock_acquire+0x1241/0x20c0
       lock_acquire+0xb0/0x400
       __mutex_lock+0x7b/0x820
       btrfs_record_root_in_trans+0x44/0x70 [btrfs]
       start_transaction+0xd2/0x500 [btrfs]
       btrfs_dirty_inode+0x44/0xd0 [btrfs]
       file_update_time+0xc6/0x120
       btrfs_page_mkwrite+0xda/0x560 [btrfs]
       do_page_mkwrite+0x4f/0x130
       do_wp_page+0x3b0/0x4f0
       handle_mm_fault+0xf47/0x1850
       do_user_addr_fault+0x1fc/0x4b0
       exc_page_fault+0x88/0x300
       asm_exc_page_fault+0x1e/0x30

other info that might help us debug this:

Chain exists of:
  &fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults

Possible unsafe locking scenario:

     CPU0                    CPU1
     ----                    ----
 lock(sb_pagefaults);
                             lock(&mm->mmap_lock#2);
                             lock(sb_pagefaults);
 lock(&fs_info->reloc_mutex);

 *** DEADLOCK ***

3 locks held by systemd-journal/509:
 #0: ffff97083bdec8b8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x12e/0x4b0
 #1: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs]
 #2: ffff97083144d6a8 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3f8/0x500 [btrfs]

stack backtrace:
CPU: 0 PID: 509 Comm: systemd-journal Not tainted 5.8.0-0.rc3.1.fc33.x86_64+debug #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Call Trace:
 dump_stack+0x92/0xc8
 check_noncircular+0x134/0x150
 __lock_acquire+0x1241/0x20c0
 lock_acquire+0xb0/0x400
 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 ? lock_acquire+0xb0/0x400
 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 __mutex_lock+0x7b/0x820
 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 ? kvm_sched_clock_read+0x14/0x30
 ? sched_clock+0x5/0x10
 ? sched_clock_cpu+0xc/0xb0
 btrfs_record_root_in_trans+0x44/0x70 [btrfs]
 start_transaction+0xd2/0x500 [btrfs]
 btrfs_dirty_inode+0x44/0xd0 [btrfs]
 file_update_time+0xc6/0x120
 btrfs_page_mkwrite+0xda/0x560 [btrfs]
 ? sched_clock+0x5/0x10
 do_page_mkwrite+0x4f/0x130
 do_wp_page+0x3b0/0x4f0
 handle_mm_fault+0xf47/0x1850
 do_user_addr_fault+0x1fc/0x4b0
 exc_page_fault+0x88/0x300
 ? asm_exc_page_fault+0x8/0x30
 asm_exc_page_fault+0x1e/0x30
RIP: 0033:0x7fa3972fdbfe
Code: Bad RIP value.

Fix this by not holding the ->device_list_mutex at this point.  The
device_list_mutex exists to protect us from modifying the device list
while the file system is running.

However it can also be modified by doing a scan on a device.  But this
action is specifically protected by the uuid_mutex, which we are holding
here.  We cannot race with opening at this point because we have the
->s_mount lock held during the mount.  Not having the
->device_list_mutex here is perfectly safe as we're not going to change
the devices at this point.

CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add some comments ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:46 +02:00
Josef Bacik
a47bd78d0c btrfs: sysfs: use NOFS for device creation
Dave hit this splat during testing btrfs/078:

  ======================================================
  WARNING: possible circular locking dependency detected
  5.8.0-rc6-default+ #1191 Not tainted
  ------------------------------------------------------
  kswapd0/75 is trying to acquire lock:
  ffffa040e9d04ff8 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]

  but task is already holding lock:
  ffffffff8b0c8040 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (fs_reclaim){+.+.}-{0:0}:
	 __lock_acquire+0x56f/0xaa0
	 lock_acquire+0xa3/0x440
	 fs_reclaim_acquire.part.0+0x25/0x30
	 __kmalloc_track_caller+0x49/0x330
	 kstrdup+0x2e/0x60
	 __kernfs_new_node.constprop.0+0x44/0x250
	 kernfs_new_node+0x25/0x50
	 kernfs_create_link+0x34/0xa0
	 sysfs_do_create_link_sd+0x5e/0xd0
	 btrfs_sysfs_add_devices_dir+0x65/0x100 [btrfs]
	 btrfs_init_new_device+0x44c/0x12b0 [btrfs]
	 btrfs_ioctl+0xc3c/0x25c0 [btrfs]
	 ksys_ioctl+0x68/0xa0
	 __x64_sys_ioctl+0x16/0x20
	 do_syscall_64+0x50/0xe0
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

  -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}:
	 __lock_acquire+0x56f/0xaa0
	 lock_acquire+0xa3/0x440
	 __mutex_lock+0xa0/0xaf0
	 btrfs_chunk_alloc+0x137/0x3e0 [btrfs]
	 find_free_extent+0xb44/0xfb0 [btrfs]
	 btrfs_reserve_extent+0x9b/0x180 [btrfs]
	 btrfs_alloc_tree_block+0xc1/0x350 [btrfs]
	 alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs]
	 __btrfs_cow_block+0x143/0x7a0 [btrfs]
	 btrfs_cow_block+0x15f/0x310 [btrfs]
	 push_leaf_right+0x150/0x240 [btrfs]
	 split_leaf+0x3cd/0x6d0 [btrfs]
	 btrfs_search_slot+0xd14/0xf70 [btrfs]
	 btrfs_insert_empty_items+0x64/0xc0 [btrfs]
	 __btrfs_commit_inode_delayed_items+0xb2/0x840 [btrfs]
	 btrfs_async_run_delayed_root+0x10e/0x1d0 [btrfs]
	 btrfs_work_helper+0x2f9/0x650 [btrfs]
	 process_one_work+0x22c/0x600
	 worker_thread+0x50/0x3b0
	 kthread+0x137/0x150
	 ret_from_fork+0x1f/0x30

  -> #0 (&delayed_node->mutex){+.+.}-{3:3}:
	 check_prev_add+0x98/0xa20
	 validate_chain+0xa8c/0x2a00
	 __lock_acquire+0x56f/0xaa0
	 lock_acquire+0xa3/0x440
	 __mutex_lock+0xa0/0xaf0
	 __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
	 btrfs_evict_inode+0x3bf/0x560 [btrfs]
	 evict+0xd6/0x1c0
	 dispose_list+0x48/0x70
	 prune_icache_sb+0x54/0x80
	 super_cache_scan+0x121/0x1a0
	 do_shrink_slab+0x175/0x420
	 shrink_slab+0xb1/0x2e0
	 shrink_node+0x192/0x600
	 balance_pgdat+0x31f/0x750
	 kswapd+0x206/0x510
	 kthread+0x137/0x150
	 ret_from_fork+0x1f/0x30

  other info that might help us debug this:

  Chain exists of:
    &delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim

   Possible unsafe locking scenario:

	 CPU0                    CPU1
	 ----                    ----
    lock(fs_reclaim);
				 lock(&fs_info->chunk_mutex);
				 lock(fs_reclaim);
    lock(&delayed_node->mutex);

   *** DEADLOCK ***

  3 locks held by kswapd0/75:
   #0: ffffffff8b0c8040 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30
   #1: ffffffff8b0b50b8 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x54/0x2e0
   #2: ffffa040e057c0e8 (&type->s_umount_key#26){++++}-{3:3}, at: trylock_super+0x16/0x50

  stack backtrace:
  CPU: 2 PID: 75 Comm: kswapd0 Not tainted 5.8.0-rc6-default+ #1191
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
  Call Trace:
   dump_stack+0x78/0xa0
   check_noncircular+0x16f/0x190
   check_prev_add+0x98/0xa20
   validate_chain+0xa8c/0x2a00
   __lock_acquire+0x56f/0xaa0
   lock_acquire+0xa3/0x440
   ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
   __mutex_lock+0xa0/0xaf0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
   ? __lock_acquire+0x56f/0xaa0
   ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
   ? lock_acquire+0xa3/0x440
   ? btrfs_evict_inode+0x138/0x560 [btrfs]
   ? btrfs_evict_inode+0x2fe/0x560 [btrfs]
   ? __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
   __btrfs_release_delayed_node.part.0+0x3f/0x310 [btrfs]
   btrfs_evict_inode+0x3bf/0x560 [btrfs]
   evict+0xd6/0x1c0
   dispose_list+0x48/0x70
   prune_icache_sb+0x54/0x80
   super_cache_scan+0x121/0x1a0
   do_shrink_slab+0x175/0x420
   shrink_slab+0xb1/0x2e0
   shrink_node+0x192/0x600
   balance_pgdat+0x31f/0x750
   kswapd+0x206/0x510
   ? _raw_spin_unlock_irqrestore+0x3e/0x50
   ? finish_wait+0x90/0x90
   ? balance_pgdat+0x750/0x750
   kthread+0x137/0x150
   ? kthread_stop+0x2a0/0x2a0
   ret_from_fork+0x1f/0x30

This is because we're holding the chunk_mutex while adding this device
and adding its sysfs entries.  We actually hold different locks in
different places when calling this function, the dev_replace semaphore
for instance in dev replace, so instead of moving this call around
simply wrap it's operations in NOFS.

CC: stable@vger.kernel.org # 4.14+
Reported-by: David Sterba <dsterba@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:46 +02:00
Josef Bacik
fbabd4a36f btrfs: return EROFS for BTRFS_FS_STATE_ERROR cases
Eric reported seeing this message while running generic/475

  BTRFS: error (device dm-3) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted

Full stack trace:

  BTRFS: error (device dm-0) in btrfs_commit_transaction:2323: errno=-5 IO failure (Error while writing out transaction)
  BTRFS info (device dm-0): forced readonly
  BTRFS warning (device dm-0): Skipping commit of aborted transaction.
  ------------[ cut here ]------------
  BTRFS: error (device dm-0) in cleanup_transaction:1894: errno=-5 IO failure
  BTRFS: Transaction aborted (error -117)
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6480 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6488 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6490 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6498 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a0 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a8 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b0 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b8 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64c0 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85e8 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85f0 len 4096 err no 10
  WARNING: CPU: 3 PID: 23985 at fs/btrfs/tree-log.c:3084 btrfs_sync_log+0xbc8/0xd60 [btrfs]
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4288 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4290 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4298 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a0 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a8 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b0 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b8 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c0 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c8 len 4096 err no 10
  BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42d0 len 4096 err no 10
  CPU: 3 PID: 23985 Comm: fsstress Tainted: G        W    L    5.8.0-rc4-default+ #1181
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
  RIP: 0010:btrfs_sync_log+0xbc8/0xd60 [btrfs]
  RSP: 0018:ffff909a44d17bd0 EFLAGS: 00010286
  RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001
  RDX: ffff8f3be41cb940 RSI: ffffffffb0108d2b RDI: ffffffffb0108ff7
  RBP: ffff909a44d17e70 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000037988 R12: ffff8f3bd20e4000
  R13: ffff8f3bd20e4428 R14: 00000000ffffff8b R15: ffff909a44d17c70
  FS:  00007f6a6ed3fb80(0000) GS:ffff8f3c3dc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f6a6ed3e000 CR3: 00000000525c0003 CR4: 0000000000160ee0
  Call Trace:
   ? finish_wait+0x90/0x90
   ? __mutex_unlock_slowpath+0x45/0x2a0
   ? lock_acquire+0xa3/0x440
   ? lockref_put_or_lock+0x9/0x30
   ? dput+0x20/0x4a0
   ? dput+0x20/0x4a0
   ? do_raw_spin_unlock+0x4b/0xc0
   ? _raw_spin_unlock+0x1f/0x30
   btrfs_sync_file+0x335/0x490 [btrfs]
   do_fsync+0x38/0x70
   __x64_sys_fsync+0x10/0x20
   do_syscall_64+0x50/0xe0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  RIP: 0033:0x7f6a6ef1b6e3
  Code: Bad RIP value.
  RSP: 002b:00007ffd01e20038 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
  RAX: ffffffffffffffda RBX: 000000000007a120 RCX: 00007f6a6ef1b6e3
  RDX: 00007ffd01e1ffa0 RSI: 00007ffd01e1ffa0 RDI: 0000000000000003
  RBP: 0000000000000003 R08: 0000000000000001 R09: 00007ffd01e2004c
  R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000009f
  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
  irq event stamp: 0
  hardirqs last  enabled at (0): [<0000000000000000>] 0x0
  hardirqs last disabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00
  softirqs last  enabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00
  softirqs last disabled at (0): [<0000000000000000>] 0x0
  ---[ end trace af146e0e38433456 ]---
  BTRFS: error (device dm-0) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted

This ret came from btrfs_write_marked_extents().  If we get an aborted
transaction via EIO before, we'll see it in btree_write_cache_pages()
and return EUCLEAN, which gets printed as "Filesystem corrupted".

Except we shouldn't be returning EUCLEAN here, we need to be returning
EROFS because EUCLEAN is reserved for actual corruption, not IO errors.

We are inconsistent about our handling of BTRFS_FS_STATE_ERROR
elsewhere, but we want to use EROFS for this particular case.  The
original transaction abort has the real error code for why we ended up
with an aborted transaction, all subsequent actions just need to return
EROFS because they may not have a trans handle and have no idea about
the original cause of the abort.

After patch "btrfs: don't WARN if we abort a transaction with EROFS" the
stacktrace will not be dumped either.

Reported-by: Eric Sandeen <esandeen@redhat.com>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add full test stacktrace ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:46 +02:00
Josef Bacik
5913139343 btrfs: document special case error codes for fs errors
We've had some discussions about what to do in certain scenarios for
error codes, specifically EUCLEAN and EROFS.  Document these near the
error handling code so its clear what their intentions are.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:46 +02:00
Josef Bacik
f95ebdbed4 btrfs: don't WARN if we abort a transaction with EROFS
If we got some sort of corruption via a read and call
btrfs_handle_fs_error() we'll set BTRFS_FS_STATE_ERROR on the fs and
complain.  If a subsequent trans handle trips over this it'll get EROFS
and then abort.  However at that point we're not aborting for the
original reason, we're aborting because we've been flipped read only.
We do not need to WARN_ON() here.

CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:46 +02:00
Filipe Manana
3ebac17ce5 btrfs: reduce contention on log trees when logging checksums
The possibility of extents being shared (through clone and deduplication
operations) requires special care when logging data checksums, to avoid
having a log tree with different checksum items that cover ranges which
overlap (which resulted in missing checksums after replaying a log tree).
Such problems were fixed in the past by the following commits:

commit 40e046acbd ("Btrfs: fix missing data checksums after replaying a
                      log tree")

commit e289f03ea7 ("btrfs: fix corrupt log due to concurrent fsync of
                      inodes with shared extents")

Test case generic/588 exercises the scenario solved by the first commit
(purely sequential and deterministic) while test case generic/457 often
triggered the case fixed by the second commit (not deterministic, requires
specific timings under concurrency).

The problems were addressed by deleting, from the log tree, any existing
checksums before logging the new ones. And also by doing the deletion and
logging of the cheksums while locking the checksum range in an extent io
tree (root->log_csum_range), to deal with the case where we have concurrent
fsyncs against files with shared extents.

That however causes more contention on the leaves of a log tree where we
store checksums (and all the nodes in the paths leading to them), even
when we do not have shared extents, or all the shared extents were created
by past transactions. It also adds a bit of contention on the spin lock of
the log_csums_range extent io tree of the log root.

This change adds a 'last_reflink_trans' field to the inode to keep track
of the last transaction where a new extent was shared between inodes
(through clone and deduplication operations). It is updated for both the
source and destination inodes of reflink operations whenever a new extent
(created in the current transaction) becomes shared by the inodes. This
field is kept in memory only, not persisted in the inode item, similar
to other existing fields (last_unlink_trans, logged_trans).

When logging checksums for an extent, if the value of 'last_reflink_trans'
is smaller then the current transaction's generation/id, we skip locking
the extent range and deletion of checksums from the log tree, since we
know we do not have new shared extents. This reduces contention on the
log tree's leaves where checksums are stored.

The following script, which uses fio, was used to measure the impact of
this change:

  $ cat test-fsync.sh
  #!/bin/bash

  DEV=/dev/sdk
  MNT=/mnt/sdk
  MOUNT_OPTIONS="-o ssd"
  MKFS_OPTIONS="-d single -m single"

  if [ $# -ne 3 ]; then
      echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ"
      exit 1
  fi

  NUM_JOBS=$1
  FILE_SIZE=$2
  FSYNC_FREQ=$3

  cat <<EOF > /tmp/fio-job.ini
  [writers]
  rw=write
  fsync=$FSYNC_FREQ
  fallocate=none
  group_reporting=1
  direct=0
  bs=64k
  ioengine=sync
  size=$FILE_SIZE
  directory=$MNT
  numjobs=$NUM_JOBS
  EOF

  echo "Using config:"
  echo
  cat /tmp/fio-job.ini
  echo

  mkfs.btrfs -f $MKFS_OPTIONS $DEV
  mount $MOUNT_OPTIONS $DEV $MNT
  fio /tmp/fio-job.ini
  umount $MNT

The tests were performed for different numbers of jobs, file sizes and
fsync frequency. A qemu VM using kvm was used, with 8 cores (the host has
12 cores, with cpu governance set to performance mode on all cores), 16GiB
of ram (the host has 64GiB) and using a NVMe device directly (without an
intermediary filesystem in the host). While running the tests, the host
was not used for anything else, to avoid disturbing the tests.

The obtained results were the following (the last line of fio's output was
pasted). Starting with 16 jobs is where a significant difference is
observable in this particular setup and hardware (differences highlighted
below). The very small differences for tests with less than 16 jobs are
possibly just noise and random.

    **** 1 job, file size 1G, fsync frequency 1 ****

before this change:

WRITE: bw=23.8MiB/s (24.9MB/s), 23.8MiB/s-23.8MiB/s (24.9MB/s-24.9MB/s), io=1024MiB (1074MB), run=43075-43075msec

after this change:

WRITE: bw=24.4MiB/s (25.6MB/s), 24.4MiB/s-24.4MiB/s (25.6MB/s-25.6MB/s), io=1024MiB (1074MB), run=41938-41938msec

    **** 2 jobs, file size 1G, fsync frequency 1 ****

before this change:

WRITE: bw=37.7MiB/s (39.5MB/s), 37.7MiB/s-37.7MiB/s (39.5MB/s-39.5MB/s), io=2048MiB (2147MB), run=54351-54351msec

after this change:

WRITE: bw=37.7MiB/s (39.5MB/s), 37.6MiB/s-37.6MiB/s (39.5MB/s-39.5MB/s), io=2048MiB (2147MB), run=54428-54428msec

    **** 4 jobs, file size 1G, fsync frequency 1 ****

before this change:

WRITE: bw=67.5MiB/s (70.8MB/s), 67.5MiB/s-67.5MiB/s (70.8MB/s-70.8MB/s), io=4096MiB (4295MB), run=60669-60669msec

after this change:

WRITE: bw=68.6MiB/s (71.0MB/s), 68.6MiB/s-68.6MiB/s (71.0MB/s-71.0MB/s), io=4096MiB (4295MB), run=59678-59678msec

    **** 8 jobs, file size 1G, fsync frequency 1 ****

before this change:

WRITE: bw=128MiB/s (134MB/s), 128MiB/s-128MiB/s (134MB/s-134MB/s), io=8192MiB (8590MB), run=64048-64048msec

after this change:

WRITE: bw=129MiB/s (135MB/s), 129MiB/s-129MiB/s (135MB/s-135MB/s), io=8192MiB (8590MB), run=63405-63405msec

    **** 16 jobs, file size 1G, fsync frequency 1 ****

before this change:

WRITE: bw=78.5MiB/s (82.3MB/s), 78.5MiB/s-78.5MiB/s (82.3MB/s-82.3MB/s), io=16.0GiB (17.2GB), run=208676-208676msec

after this change:

WRITE: bw=110MiB/s (115MB/s), 110MiB/s-110MiB/s (115MB/s-115MB/s), io=16.0GiB (17.2GB), run=149295-149295msec
(+40.1% throughput, -28.5% runtime)

    **** 32 jobs, file size 1G, fsync frequency 1 ****

before this change:

WRITE: bw=58.8MiB/s (61.7MB/s), 58.8MiB/s-58.8MiB/s (61.7MB/s-61.7MB/s), io=32.0GiB (34.4GB), run=557134-557134msec

after this change:

WRITE: bw=76.1MiB/s (79.8MB/s), 76.1MiB/s-76.1MiB/s (79.8MB/s-79.8MB/s), io=32.0GiB (34.4GB), run=430550-430550msec
(+29.4% throughput, -22.7% runtime)

    **** 64 jobs, file size 512M, fsync frequency 1 ****

before this change:

WRITE: bw=65.8MiB/s (68.0MB/s), 65.8MiB/s-65.8MiB/s (68.0MB/s-68.0MB/s), io=32.0GiB (34.4GB), run=498055-498055msec

after this change:

WRITE: bw=85.1MiB/s (89.2MB/s), 85.1MiB/s-85.1MiB/s (89.2MB/s-89.2MB/s), io=32.0GiB (34.4GB), run=385116-385116msec
(+29.3% throughput, -22.7% runtime)

    **** 128 jobs, file size 256M, fsync frequency 1 ****

before this change:

WRITE: bw=54.7MiB/s (57.3MB/s), 54.7MiB/s-54.7MiB/s (57.3MB/s-57.3MB/s), io=32.0GiB (34.4GB), run=599373-599373msec

after this change:

WRITE: bw=121MiB/s (126MB/s), 121MiB/s-121MiB/s (126MB/s-126MB/s), io=32.0GiB (34.4GB), run=271907-271907msec
(+121.2% throughput, -54.6% runtime)

    **** 256 jobs, file size 256M, fsync frequency 1 ****

before this change:

WRITE: bw=69.2MiB/s (72.5MB/s), 69.2MiB/s-69.2MiB/s (72.5MB/s-72.5MB/s), io=64.0GiB (68.7GB), run=947536-947536msec

after this change:

WRITE: bw=121MiB/s (127MB/s), 121MiB/s-121MiB/s (127MB/s-127MB/s), io=64.0GiB (68.7GB), run=541916-541916msec
(+74.9% throughput, -42.8% runtime)

    **** 512 jobs, file size 128M, fsync frequency 1 ****

before this change:

WRITE: bw=85.4MiB/s (89.5MB/s), 85.4MiB/s-85.4MiB/s (89.5MB/s-89.5MB/s), io=64.0GiB (68.7GB), run=767734-767734msec

after this change:

WRITE: bw=141MiB/s (147MB/s), 141MiB/s-141MiB/s (147MB/s-147MB/s), io=64.0GiB (68.7GB), run=466022-466022msec
(+65.1% throughput, -39.3% runtime)

    **** 1024 jobs, file size 128M, fsync frequency 1 ****

before this change:

WRITE: bw=115MiB/s (120MB/s), 115MiB/s-115MiB/s (120MB/s-120MB/s), io=128GiB (137GB), run=1143775-1143775msec

after this change:

WRITE: bw=171MiB/s (180MB/s), 171MiB/s-171MiB/s (180MB/s-180MB/s), io=128GiB (137GB), run=764843-764843msec
(+48.7% throughput, -33.1% runtime)

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:45 +02:00
Nikolay Borisov
b69d1ee923 btrfs: remove done label in writepage_delalloc
Since there is not common cleanup run after the label it makes it
somewhat redundant.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:45 +02:00
Qu Wenruo
fd7fb634d6 btrfs: add comments for btrfs_reserve_flush_enum
This enum is the interface exposed to developers.

Although we have a detailed comment explaining the whole idea of space
flushing at the beginning of space-info.c, the exposed enum interface
doesn't have any comment.

Some corner cases, like BTRFS_RESERVE_FLUSH_ALL and
BTRFS_RESERVE_FLUSH_ALL_STEAL can be interrupted by fatal signals, are
not explained at all.

So add some simple comments for these enums as a quick reference.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:45 +02:00
Qu Wenruo
44d354abf3 btrfs: relocation: review the call sites which can be interrupted by signal
Since most metadata reservation calls can return -EINTR when get
interrupted by fatal signal, we need to review the all the metadata
reservation call sites.

In relocation code, the metadata reservation happens in the following
sites:

- btrfs_block_rsv_refill() in merge_reloc_root()
  merge_reloc_root() is a pretty critical section, we don't want to be
  interrupted by signal, so change the flush status to
  BTRFS_RESERVE_FLUSH_LIMIT, so it won't get interrupted by signal.
  Since such change can be ENPSPC-prone, also shrink the amount of
  metadata to reserve least amount avoid deadly ENOSPC there.

- btrfs_block_rsv_refill() in reserve_metadata_space()
  It calls with BTRFS_RESERVE_FLUSH_LIMIT, which won't get interrupted
  by signal.

- btrfs_block_rsv_refill() in prepare_to_relocate()

- btrfs_block_rsv_add() in prepare_to_relocate()

- btrfs_block_rsv_refill() in relocate_block_group()

- btrfs_delalloc_reserve_metadata() in relocate_file_extent_cluster()

- btrfs_start_transaction() in relocate_block_group()

- btrfs_start_transaction() in create_reloc_inode()
  Can be interrupted by fatal signal and we can handle it easily.
  For these call sites, just catch the -EINTR value in btrfs_balance()
  and count them as canceled.

CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:45 +02:00
Qu Wenruo
f3e3d9cc35 btrfs: avoid possible signal interruption of btrfs_drop_snapshot() on relocation tree
[BUG]
There is a bug report about bad signal timing could lead to read-only
fs during balance:

  BTRFS info (device xvdb): balance: start -d -m -s
  BTRFS info (device xvdb): relocating block group 73001861120 flags metadata
  BTRFS info (device xvdb): found 12236 extents, stage: move data extents
  BTRFS info (device xvdb): relocating block group 71928119296 flags data
  BTRFS info (device xvdb): found 3 extents, stage: move data extents
  BTRFS info (device xvdb): found 3 extents, stage: update data pointers
  BTRFS info (device xvdb): relocating block group 60922265600 flags metadata
  BTRFS: error (device xvdb) in btrfs_drop_snapshot:5505: errno=-4 unknown
  BTRFS info (device xvdb): forced readonly
  BTRFS info (device xvdb): balance: ended with status: -4

[CAUSE]
The direct cause is the -EINTR from the following call chain when a
fatal signal is pending:

 relocate_block_group()
 |- clean_dirty_subvols()
    |- btrfs_drop_snapshot()
       |- btrfs_start_transaction()
          |- btrfs_delayed_refs_rsv_refill()
             |- btrfs_reserve_metadata_bytes()
                |- __reserve_metadata_bytes()
                   |- wait_reserve_ticket()
                      |- prepare_to_wait_event();
                      |- ticket->error = -EINTR;

Normally this behavior is fine for most btrfs_start_transaction()
callers, as they need to catch any other error, same for the signal, and
exit ASAP.

However for balance, especially for the clean_dirty_subvols() case, we're
already doing cleanup works, getting -EINTR from btrfs_drop_snapshot()
could cause a lot of unexpected problems.

From the mentioned forced read-only report, to later balance error due
to half dropped reloc trees.

[FIX]
Fix this problem by using btrfs_join_transaction() if
btrfs_drop_snapshot() is called from relocation context.

Since btrfs_join_transaction() won't get interrupted by signal, we can
continue the cleanup.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>3
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:45 +02:00
Qu Wenruo
5cb502f4ab btrfs: relocation: allow signal to cancel balance
Although btrfs balance can be canceled with "btrfs balance cancel"
command, it's still almost muscle memory to press Ctrl-C to cancel a
long running btrfs balance.

So allow btrfs balance to check signal to determine if it should exit.
The cancellation points are in known location and we're only adding one
more reason, so this should be safe.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:44 +02:00
Nikolay Borisov
813f8a0e26 btrfs: raid56: remove out label in __raid56_parity_recover
There's no cleanup that occurs so we can simply return 0 directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:44 +02:00
David Sterba
f37c563bab btrfs: add missing check for nocow and compression inode flags
User Forza reported on IRC that some invalid combinations of file
attributes are accepted by chattr.

The NODATACOW and compression file flags/attributes are mutually
exclusive, but they could be set by 'chattr +c +C' on an empty file. The
nodatacow will be in effect because it's checked first in
btrfs_run_delalloc_range.

Extend the flag validation to catch the following cases:

  - input flags are conflicting
  - old and new flags are conflicting
  - initialize the local variable with inode flags after inode ls locked

Inode attributes take precedence over mount options and are an
independent setting.

Nocompress would be a no-op with nodatacow, but we don't want to mix
any compression-related options with nodatacow.

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:44 +02:00
Anand Jain
4faf55b038 btrfs: don't traverse into the seed devices in show_devname
->show_devname currently shows the lowest devid in the list. As the seed
devices have the lowest devid in the sprouted filesystem, the userland
tool such as findmnt end up seeing seed device instead of the device from
the read-writable sprouted filesystem. As shown below.

 mount /dev/sda /btrfs
 mount: /btrfs: WARNING: device write-protected, mounted read-only.

 findmnt --output SOURCE,TARGET,UUID /btrfs
 SOURCE   TARGET UUID
 /dev/sda /btrfs 899f7027-3e46-4626-93e7-7d4c9ad19111

 btrfs dev add -f /dev/sdb /btrfs

 umount /btrfs
 mount /dev/sdb /btrfs

 findmnt --output SOURCE,TARGET,UUID /btrfs
 SOURCE   TARGET UUID
 /dev/sda /btrfs 899f7027-3e46-4626-93e7-7d4c9ad19111

All sprouts from a single seed will show the same seed device and the
same fsid. That's confusing.
This is causing problems in our prototype as there isn't any reference
to the sprout file-system(s) which is being used for actual read and
write.

This was added in the patch which implemented the show_devname in btrfs
commit 9c5085c147 ("Btrfs: implement ->show_devname").
I tried to look for any particular reason that we need to show the seed
device, there isn't any.

So instead, do not traverse through the seed devices, just show the
lowest devid in the sprouted fsid.

After the patch:

 mount /dev/sda /btrfs
 mount: /btrfs: WARNING: device write-protected, mounted read-only.

 findmnt --output SOURCE,TARGET,UUID /btrfs
 SOURCE   TARGET UUID
 /dev/sda /btrfs 899f7027-3e46-4626-93e7-7d4c9ad19111

 btrfs dev add -f /dev/sdb /btrfs
 mount -o rw,remount /dev/sdb /btrfs

 findmnt --output SOURCE,TARGET,UUID /btrfs
 SOURCE   TARGET UUID
 /dev/sdb /btrfs 595ca0e6-b82e-46b5-b9e2-c72a6928be48

 mount /dev/sda /btrfs1
 mount: /btrfs1: WARNING: device write-protected, mounted read-only.

 btrfs dev add -f /dev/sdc /btrfs1

 findmnt --output SOURCE,TARGET,UUID /btrfs1
 SOURCE   TARGET  UUID
 /dev/sdc /btrfs1 ca1dbb7a-8446-4f95-853c-a20f3f82bdbb

 cat /proc/self/mounts | grep btrfs
 /dev/sdb /btrfs btrfs rw,relatime,noacl,space_cache,subvolid=5,subvol=/ 0 0
 /dev/sdc /btrfs1 btrfs ro,relatime,noacl,space_cache,subvolid=5,subvol=/ 0 0

Reported-by: Martin K. Petersen <martin.petersen@oracle.com>
CC: stable@vger.kernel.org # 4.19+
Tested-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:44 +02:00
Qu Wenruo
a3cf0e4342 btrfs: qgroup: free per-trans reserved space when a subvolume gets dropped
[BUG]
Sometime fsstress could lead to qgroup warning for case like
generic/013:

  BTRFS warning (device dm-3): qgroup 0/259 has unreleased space, type 1 rsv 81920
  ------------[ cut here ]------------
  WARNING: CPU: 9 PID: 24535 at fs/btrfs/disk-io.c:4142 close_ctree+0x1dc/0x323 [btrfs]
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:close_ctree+0x1dc/0x323 [btrfs]
  Call Trace:
   btrfs_put_super+0x15/0x17 [btrfs]
   generic_shutdown_super+0x72/0x110
   kill_anon_super+0x18/0x30
   btrfs_kill_super+0x17/0x30 [btrfs]
   deactivate_locked_super+0x3b/0xa0
   deactivate_super+0x40/0x50
   cleanup_mnt+0x135/0x190
   __cleanup_mnt+0x12/0x20
   task_work_run+0x64/0xb0
   __prepare_exit_to_usermode+0x1bc/0x1c0
   __syscall_return_slowpath+0x47/0x230
   do_syscall_64+0x64/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 6c341cdf9b6cc3c1 ]---
  BTRFS error (device dm-3): qgroup reserved space leaked

While that subvolume 259 is no longer in that filesystem.

[CAUSE]
Normally per-trans qgroup reserved space is freed when a transaction is
committed, in commit_fs_roots().

However for completely dropped subvolume, that subvolume is completely
gone, thus is no longer in the fs_roots_radix, and its per-trans
reserved qgroup will never be freed.

Since the subvolume is already gone, leaked per-trans space won't cause
any trouble for end users.

[FIX]
Just call btrfs_qgroup_free_meta_all_pertrans() before a subvolume is
completely dropped.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:44 +02:00
Tom Rix
d60ba8de11 btrfs: ref-verify: fix memory leak in add_block_entry
clang static analysis flags this error

fs/btrfs/ref-verify.c:290:3: warning: Potential leak of memory pointed to by 're' [unix.Malloc]
                kfree(be);
                ^~~~~

The problem is in this block of code:

	if (root_objectid) {
		struct root_entry *exist_re;

		exist_re = insert_root_entry(&exist->roots, re);
		if (exist_re)
			kfree(re);
	}

There is no 'else' block freeing when root_objectid is 0. Add the
missing kfree to the else branch.

Fixes: fd708b81d9 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:43 +02:00
David Sterba
d85327b1d8 btrfs: prefetch chunk tree leaves at mount
The whole chunk tree is read at mount time so we can utilize readahead
to get the tree blocks to memory before we read the items. The idea is
from Robbie, but instead of updating search slot readahead, this patch
implements the chunk tree readahead manually from nodes on level 1.

We've decided to do specific readahead optimizations and then unify them
under a common API so we don't break everything by changing the search
slot readahead logic.

Higher chunk trees grow on large filesystems (many terabytes), and
prefetching just level 1 seems to be sufficient. Provided example was
from a 200TiB filesystem with chunk tree level 2.

CC: Robbie Ko <robbieko@synology.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:43 +02:00
Johannes Thumshirn
49bac89768 btrfs: add metadata_uuid to FS_INFO ioctl
Add retrieval of the filesystem's metadata UUID to the fsinfo ioctl.
This is driven by setting the BTRFS_FS_INFO_FLAG_METADATA_UUID flag in
btrfs_ioctl_fs_info_args::flags.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:43 +02:00
Johannes Thumshirn
0fb408a558 btrfs: add filesystem generation to FS_INFO ioctl
Add retrieval of the filesystem's generation to the fsinfo ioctl. This is
driven by setting the BTRFS_FS_INFO_FLAG_GENERATION flag in
btrfs_ioctl_fs_info_args::flags.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:43 +02:00
Johannes Thumshirn
137c541821 btrfs: pass checksum type via BTRFS_IOC_FS_INFO ioctl
With the recent addition of filesystem checksum types other than CRC32c,
it is not anymore hard-coded which checksum type a btrfs filesystem uses.

Up to now there is no good way to read the filesystem checksum, apart from
reading the filesystem UUID and then query sysfs for the checksum type.

Add a new csum_type and csum_size fields to the BTRFS_IOC_FS_INFO ioctl
command which usually is used to query filesystem features. Also add a
flags member indicating that the kernel responded with a set csum_type and
csum_size field.

For compatibility reasons, only return the csum_type and csum_size if
the BTRFS_FS_INFO_FLAG_CSUM_INFO flag was passed to the kernel. Also
clear any unknown flags so we don't pass false positives to user-space
newer than the kernel.

To simplify further additions to the ioctl, also switch the padding to a
u8 array. Pahole was used to verify the result of this switch:

The csum members are added before flags, which might look odd, but this
is to keep the alignment requirements and not to introduce holes in the
structure.

  $ pahole -C btrfs_ioctl_fs_info_args fs/btrfs/btrfs.ko
  struct btrfs_ioctl_fs_info_args {
	  __u64                      max_id;               /*     0     8 */
	  __u64                      num_devices;          /*     8     8 */
	  __u8                       fsid[16];             /*    16    16 */
	  __u32                      nodesize;             /*    32     4 */
	  __u32                      sectorsize;           /*    36     4 */
	  __u32                      clone_alignment;      /*    40     4 */
	  __u16                      csum_type;            /*    44     2 */
	  __u16                      csum_size;            /*    46     2 */
	  __u64                      flags;                /*    48     8 */
	  __u8                       reserved[968];        /*    56   968 */

	  /* size: 1024, cachelines: 16, members: 10 */
  };

Fixes: 3951e7f050 ("btrfs: add xxhash64 to checksumming algorithms")
Fixes: 3831bf0094 ("btrfs: add sha256 to checksumming algorithm")
CC: stable@vger.kernel.org # 5.5+
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:43 +02:00
Qu Wenruo
adca4d945c btrfs: qgroup: remove ASYNC_COMMIT mechanism in favor of reserve retry-after-EDQUOT
commit a514d63882 ("btrfs: qgroup: Commit transaction in advance to
reduce early EDQUOT") tries to reduce the early EDQUOT problems by
checking the qgroup free against threshold and tries to wake up commit
kthread to free some space.

The problem of that mechanism is, it can only free qgroup per-trans
metadata space, can't do anything to data, nor prealloc qgroup space.

Now since we have the ability to flush qgroup space, and implemented
retry-after-EDQUOT behavior, such mechanism can be completely replaced.

So this patch will cleanup such mechanism in favor of
retry-after-EDQUOT.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:43 +02:00
Qu Wenruo
c53e965360 btrfs: qgroup: try to flush qgroup space when we get -EDQUOT
[PROBLEM]
There are known problem related to how btrfs handles qgroup reserved
space.  One of the most obvious case is the the test case btrfs/153,
which do fallocate, then write into the preallocated range.

  btrfs/153 1s ... - output mismatch (see xfstests-dev/results//btrfs/153.out.bad)
      --- tests/btrfs/153.out     2019-10-22 15:18:14.068965341 +0800
      +++ xfstests-dev/results//btrfs/153.out.bad      2020-07-01 20:24:40.730000089 +0800
      @@ -1,2 +1,5 @@
       QA output created by 153
      +pwrite: Disk quota exceeded
      +/mnt/scratch/testfile2: Disk quota exceeded
      +/mnt/scratch/testfile2: Disk quota exceeded
       Silence is golden
      ...
      (Run 'diff -u xfstests-dev/tests/btrfs/153.out xfstests-dev/results//btrfs/153.out.bad'  to see the entire diff)

[CAUSE]
Since commit c6887cd111 ("Btrfs: don't do nocow check unless we have to"),
we always reserve space no matter if it's COW or not.

Such behavior change is mostly for performance, and reverting it is not
a good idea anyway.

For preallcoated extent, we reserve qgroup data space for it already,
and since we also reserve data space for qgroup at buffered write time,
it needs twice the space for us to write into preallocated space.

This leads to the -EDQUOT in buffered write routine.

And we can't follow the same solution, unlike data/meta space check,
qgroup reserved space is shared between data/metadata.
The EDQUOT can happen at the metadata reservation, so doing NODATACOW
check after qgroup reservation failure is not a solution.

[FIX]
To solve the problem, we don't return -EDQUOT directly, but every time
we got a -EDQUOT, we try to flush qgroup space:

- Flush all inodes of the root
  NODATACOW writes will free the qgroup reserved at run_dealloc_range().
  However we don't have the infrastructure to only flush NODATACOW
  inodes, here we flush all inodes anyway.

- Wait for ordered extents
  This would convert the preallocated metadata space into per-trans
  metadata, which can be freed in later transaction commit.

- Commit transaction
  This will free all per-trans metadata space.

Also we don't want to trigger flush multiple times, so here we introduce
a per-root wait list and a new root status, to ensure only one thread
starts the flushing.

Fixes: c6887cd111 ("Btrfs: don't do nocow check unless we have to")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:42 +02:00
Qu Wenruo
263da812e8 btrfs: qgroup: allow to unreserve range without releasing other ranges
[PROBLEM]
Before this patch, when btrfs_qgroup_reserve_data() fails, we free all
reserved space of the changeset.

For example:
	ret = btrfs_qgroup_reserve_data(inode, changeset, 0, SZ_1M);
	ret = btrfs_qgroup_reserve_data(inode, changeset, SZ_1M, SZ_1M);
	ret = btrfs_qgroup_reserve_data(inode, changeset, SZ_2M, SZ_1M);

If the last btrfs_qgroup_reserve_data() failed, it will release the
entire [0, 3M) range.

This behavior is kind of OK for now, as when we hit -EDQUOT, we normally
go error handling and need to release all reserved ranges anyway.

But this also means the following call is not possible:

	ret = btrfs_qgroup_reserve_data();
	if (ret == -EDQUOT) {
		/* Do something to free some qgroup space */
		ret = btrfs_qgroup_reserve_data();
	}

As if the first btrfs_qgroup_reserve_data() fails, it will free all
reserved qgroup space.

[CAUSE]
This is because we release all reserved ranges when
btrfs_qgroup_reserve_data() fails.

[FIX]
This patch will implement a new function, qgroup_unreserve_range(), to
iterate through the ulist nodes, to find any nodes in the failure range,
and remove the EXTENT_QGROUP_RESERVED bits from the io_tree, and
decrease the extent_changeset::bytes_changed, so that we can revert to
previous state.

This allows later patches to retry btrfs_qgroup_reserve_data() if EDQUOT
happens.

Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:42 +02:00
Josef Bacik
48aaeebe4e btrfs: convert block group refcount to refcount_t
We have refcount_t now with the associated library to handle refcounts,
which gives us extra debugging around reference count mistakes that may
be made.  For example it'll warn on any transition from 0->1 or 0->-1,
which is handy for noticing cases where we've messed up reference
counting.  Convert the block group ref counting from an atomic_t to
refcount_t and use the appropriate helpers.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:42 +02:00
Marcos Paulo de Souza
60f8667b61 btrfs: add multi-statement protection to btrfs_set/clear_and_info macros
Multi-statement macros should be enclosed in do/while(0) block to make
their use safe in single statement if conditions. All current uses of
the macros are safe, so this change is for future protection.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:42 +02:00
Nikolay Borisov
93c4c033ec btrfs: remove fail label in check_compressed_csum
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:42 +02:00
Nikolay Borisov
b7d2083a36 btrfs: raid56: don't opencode swap() in __raid_recover_end_io
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:41 +02:00
Nikolay Borisov
8302586327 btrfs: raid56: use in_range where applicable
While at it use the opportunity to simplify find_logical_bio_stripe by
reducing the scope of 'stripe_start' variable and squash the
sector-to-bytes conversion on one line.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:41 +02:00
Nikolay Borisov
bf28a605e6 btrfs: raid56: assign bio in while() when using bio_list_pop
Unify the style in the file such that return value of bio_list_pop is
assigned directly in the while loop. This is in line with the rest of
the kernel.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:41 +02:00
Nikolay Borisov
f90ae76a5c btrfs: raid56: remove redundant device check in rbio_add_io_page
The merging logic is always executed if the current stripe's device
is not missing. So there's no point in duplicating the check. Simply
remove it, while at it reduce the scope of the 'last_end' variable.
If the current stripe's device is missing we fail the stripe early on.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:41 +02:00
Nikolay Borisov
608769a4e4 btrfs: always initialize btrfs_bio::tgtdev_map/raid_map pointers
Since btrfs_bio always contains the extra space for the tgtdev_map and
raid_maps it's pointless to make the assignment iff specific conditions
are met.

Instead, always assign the pointers to their correct value at allocation
time. To accommodate this change also move code a bit in
__btrfs_map_block so that btrfs_bio::stripes array is always initialized
before the raid_map, subsequently move the call to sort_parity_stripes
in the 'if' building the raid_map, retaining the old behavior.

To better understand the change, there are 2 aspects to this:

1. The original code is harder to grasp because the calculations for
   initializing raid_map/tgtdev ponters are apart from the initial
   allocation of memory. Having them predicated on 2 separate checks
   doesn't help that either... So by moving the initialisation in
   alloc_btrfs_bio puts everything together.

2. tgtdev/raid_maps are now always initialized despite sometimes they
   might be equal i.e __btrfs_map_block_for_discard calls
   alloc_btrfs_bio with tgtdev = 0 but their usage should be predicated
   on external checks i.e. just because those pointers are non-null
   doesn't mean they are valid per-se. And actually while taking another
   look at __btrfs_map_block I saw a discrepancy:

   Original code initialised tgtdev_map if the following check is true:

	   if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL)

   However, further down tgtdev_map is only used if the following check
   is true:

	if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL && need_full_stripe(op))

  e.g. the additional need_full_stripe(op) predicate is there.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ copy more details from mail discussion ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:41 +02:00
Nikolay Borisov
3092c68fc5 btrfs: sysfs: add bdi link to the fsid directory
Since BTRFS uses a private bdi it makes sense to create a link to this
bdi under /sys/fs/btrfs/<UUID>/bdi. This allows size of read ahead to
be controlled. Without this patch it's not possible to uniquely identify
which bdi pertains to which btrfs filesystem in the case of multiple
btrfs filesystems.

It's fine to simply call sysfs_remove_link without checking if the
link indeed has been created. The call path

sysfs_remove_link
 kernfs_remove_by_name
  kernfs_remove_by_name_ns

will simply return -ENOENT in case it doesn't exist.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:41 +02:00
Nikolay Borisov
5a9472fe7f btrfs: increment corrupt device counter during compressed read
If a compressed read fails due to checksum error only a line is printed
to dmesg, device corrupt counter is not modified.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:40 +02:00
Nikolay Borisov
26056eab4b btrfs: remove needless ASSERT check of orig_bio in end_compressed_bio_read
compressed_bio::orig_bio is always set in btrfs_submit_compressed_read
before any bio submission is performed. Since that function is always
called with a valid bio it renders the ASSERT unnecessary.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:40 +02:00
Nikolay Borisov
814723e0a5 btrfs: increment device corruption error in case of checksum error
Now that btrfs_io_bio have access to btrfs_device we can safely
increment the device corruption counter on error. There is one notable
exception - repair bios for raid. Since those don't go through the
normal submit_stripe_bio callpath but through raid56_parity_recover thus
repair bios won't have their device set.

Scrub increments the corruption counter for checksum mismatch as well
but does not call this function.

Link: https://lore.kernel.org/linux-btrfs/4857863.FCrPRfMyHP@liv/
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:40 +02:00
Nikolay Borisov
3eee86c8fd btrfs: don't check for btrfs_device::bdev in btrfs_end_bio
btrfs_map_bio ensures that all submitted bios to devices have valid
btrfs_device::bdev so this check can be removed from btrfs_end_bio. This
check was added in june 2012 597a60fade ("Btrfs: don't count I/O
statistic read errors for missing devices") but then in October of the
same year another commit de1ee92ac3 ("Btrfs: recheck bio against
block device when we map the bio") started checking for the presence of
btrfs_device::bdev before actually issuing the bio.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:40 +02:00
Nikolay Borisov
c31efbdf23 btrfs: record btrfs_device directly in btrfs_io_bio
Instead of recording stripe_index and using that to access correct
btrfs_device from btrfs_bio::stripes record the btrfs_device in
btrfs_io_bio. This will enable endio handlers to increment device
error counters on checksum errors.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:40 +02:00
Nikolay Borisov
3526302f26 btrfs: streamline btrfs_get_io_failure_record logic
Make the function directly return a pointer to a failure record and
adjust callers to handle it. Also refactor the logic inside so that
the case which allocates the failure record for the first time is not
handled in an 'if' arm, saving us a level of indentation. Finally make
the function static as it's not used outside of extent_io.c .

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:39 +02:00
Nikolay Borisov
2279a27053 btrfs: make get_state_failrec return failrec directly
Only failure that get_state_failrec can get is if there is no failure
for the given address. There is no reason why the function should return
a status code and use a separate parameter for returning the actual
failure rec (if one is found). Simplify it by making the return type
a pointer and return ERR_PTR value in case of errors.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:39 +02:00
David Sterba
b90a4ab6ba btrfs: remove deprecated mount option subvolrootid
The option subvolrootid used to be a workaround for mounting subvolumes
and ineffective since 5e2a4b25da ("btrfs: deprecate subvolrootid mount
option"). We have subvol= that works and we don't need to keep the
cruft, let's remove it.

Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:39 +02:00
David Sterba
d801e7a355 btrfs: remove deprecated mount option alloc_start
The mount option alloc_start has no effect since 0d0c71b317 ("btrfs:
obsolete and remove mount option alloc_start") which has details why
it's been deprecated. We can remove it.

Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:39 +02:00
Filipe Manana
a93e01682e btrfs: remove no longer needed use of log_writers for the log root tree
When syncing the log, we used to update the log root tree without holding
neither the log_mutex of the subvolume root nor the log_mutex of log root
tree.

We used to have two critical sections delimited by the log_mutex of the
log root tree, so in the first one we incremented the log_writers of the
log root tree and on the second one we decremented it and waited for the
log_writers counter to go down to zero. This was because the update of
the log root tree happened between the two critical sections.

The use of two critical sections allowed a little bit more of parallelism
and required the use of the log_writers counter, necessary to make sure
we didn't miss any log root tree update when we have multiple tasks trying
to sync the log in parallel.

However after commit 06989c799f ("Btrfs: fix race updating log root
item during fsync") the log root tree update was moved into a critical
section delimited by the subvolume's log_mutex. Later another commit
moved the log tree update from that critical section into the second
critical section delimited by the log_mutex of the log root tree. Both
commits addressed different bugs.

The end result is that the first critical section delimited by the
log_mutex of the log root tree became pointless, since there's nothing
done between it and the second critical section, we just have an unlock
of the log_mutex followed by a lock operation. This means we can merge
both critical sections, as the first one does almost nothing now, and we
can stop using the log_writers counter of the log root tree, which was
incremented in the first critical section and decremented in the second
criticial section, used to make sure no one in the second critical section
started writeback of the log root tree before some other task updated it.

So just remove the mutex_unlock() followed by mutex_lock() of the log root
tree, as well as the use of the log_writers counter for the log root tree.

This patch is part of a series that has the following patches:

1/4 btrfs: only commit the delayed inode when doing a full fsync
2/4 btrfs: only commit delayed items at fsync if we are logging a directory
3/4 btrfs: stop incremening log_batch for the log root tree when syncing log
4/4 btrfs: remove no longer needed use of log_writers for the log root tree

After the entire patchset applied I saw about 12% decrease on max latency
reported by dbench. The test was done on a qemu vm, with 8 cores, 16Gb of
ram, using kvm and using a raw NVMe device directly (no intermediary fs on
the host). The test was invoked like the following:

  mkfs.btrfs -f /dev/sdk
  mount -o ssd -o nospace_cache /dev/sdk /mnt/sdk
  dbench -D /mnt/sdk -t 300 8
  umount /mnt/dsk

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:39 +02:00
Filipe Manana
28a9579561 btrfs: stop incremening log_batch for the log root tree when syncing log
We are incrementing the log_batch atomic counter of the root log tree but
we never use that counter, it's used only for the log trees of subvolume
roots. We started doing it when we moved the log_batch and log_write
counters from the global, per fs, btrfs_fs_info structure, into the
btrfs_root structure in commit 7237f18336 ("Btrfs: fix tree logs
parallel sync").

So just stop doing it for the log root tree and add a comment over the
field declaration so inform it's used only for log trees of subvolume
roots.

This patch is part of a series that has the following patches:

1/4 btrfs: only commit the delayed inode when doing a full fsync
2/4 btrfs: only commit delayed items at fsync if we are logging a directory
3/4 btrfs: stop incremening log_batch for the log root tree when syncing log
4/4 btrfs: remove no longer needed use of log_writers for the log root tree

After the entire patchset applied I saw about 12% decrease on max latency
reported by dbench. The test was done on a qemu vm, with 8 cores, 16Gb of
ram, using kvm and using a raw NVMe device directly (no intermediary fs on
the host). The test was invoked like the following:

  mkfs.btrfs -f /dev/sdk
  mount -o ssd -o nospace_cache /dev/sdk /mnt/sdk
  dbench -D /mnt/sdk -t 300 8
  umount /mnt/dsk

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:39 +02:00
Filipe Manana
5aa7d1a7f4 btrfs: only commit delayed items at fsync if we are logging a directory
When logging an inode we are committing its delayed items if either the
inode is a directory or if it is a new inode, created in the current
transaction.

We need to do it for directories, since new directory indexes are stored
as delayed items of the inode and when logging a directory we need to be
able to access all indexes from the fs/subvolume tree in order to figure
out which index ranges need to be logged.

However for new inodes that are not directories, we do not need to do it
because the only type of delayed item they can have is the inode item, and
we are guaranteed to always log an up to date version of the inode item:

*) for a full fsync we do it by committing the delayed inode and then
   copying the item from the fs/subvolume tree with
   copy_inode_items_to_log();

*) for a fast fsync we always log the inode item based on the contents of
   the in-memory struct btrfs_inode. We guarantee this is always done since
   commit e4545de5b0 ("Btrfs: fix fsync data loss after append write").

So stop running delayed items for a new inodes that are not directories,
since that forces committing the delayed inode into the fs/subvolume tree,
wasting time and adding contention to the tree when a full fsync is not
required. We will only do it in case a fast fsync is needed.

This patch is part of a series that has the following patches:

1/4 btrfs: only commit the delayed inode when doing a full fsync
2/4 btrfs: only commit delayed items at fsync if we are logging a directory
3/4 btrfs: stop incremening log_batch for the log root tree when syncing log
4/4 btrfs: remove no longer needed use of log_writers for the log root tree

After the entire patchset applied I saw about 12% decrease on max latency
reported by dbench. The test was done on a qemu vm, with 8 cores, 16Gb of
ram, using kvm and using a raw NVMe device directly (no intermediary fs on
the host). The test was invoked like the following:

  mkfs.btrfs -f /dev/sdk
  mount -o ssd -o nospace_cache /dev/sdk /mnt/sdk
  dbench -D /mnt/sdk -t 300 8
  umount /mnt/dsk

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:38 +02:00
Filipe Manana
8c8648dd1f btrfs: only commit the delayed inode when doing a full fsync
Commit 2c2c452b0c ("Btrfs: fix fsync when extend references are added
to an inode") forced a commit of the delayed inode when logging an inode
in order to ensure we would end up logging the inode item during a full
fsync. By committing the delayed inode, we updated the inode item in the
fs/subvolume tree and then later when copying items from leafs modified in
the current transaction into the log tree (with copy_inode_items_to_log())
we ended up copying the inode item from the fs/subvolume tree into the log
tree. Logging an up to date version of the inode item is required to make
sure at log replay time we get the link count fixup triggered among other
things (replay xattr deletes, etc). The test case generic/040 from fstests
exercises the bug which that commit fixed.

However for a fast fsync we don't need to commit the delayed inode because
we always log an up to date version of the inode item based on the struct
btrfs_inode we have in-memory. We started doing this for fast fsyncs since
commit e4545de5b0 ("Btrfs: fix fsync data loss after append write").

So just stop committing the delayed inode if we are doing a fast fsync,
we are only wasting time and adding contention on fs/subvolume tree.

This patch is part of a series that has the following patches:

1/4 btrfs: only commit the delayed inode when doing a full fsync
2/4 btrfs: only commit delayed items at fsync if we are logging a directory
3/4 btrfs: stop incremening log_batch for the log root tree when syncing log
4/4 btrfs: remove no longer needed use of log_writers for the log root tree

After the entire patchset applied I saw about 12% decrease on max latency
reported by dbench. The test was done on a qemu vm, with 8 cores, 16Gb of
ram, using kvm and using a raw NVMe device directly (no intermediary fs on
the host). The test was invoked like the following:

  mkfs.btrfs -f /dev/sdk
  mount -o ssd -o nospace_cache /dev/sdk /mnt/sdk
  dbench -D /mnt/sdk -t 300 8
  umount /mnt/dsk

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:38 +02:00
Qu Wenruo
2dfb1e43f5 btrfs: preallocate anon block device at first phase of snapshot creation
[BUG]
When the anonymous block device pool is exhausted, subvolume/snapshot
creation fails with EMFILE (Too many files open). This has been reported
by a user. The allocation happens in the second phase during transaction
commit where it's only way out is to abort the transaction

  BTRFS: Transaction aborted (error -24)
  WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs]
  RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs]
  Call Trace:
   create_pending_snapshots+0x82/0xa0 [btrfs]
   btrfs_commit_transaction+0x275/0x8c0 [btrfs]
   btrfs_mksubvol+0x4b9/0x500 [btrfs]
   btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs]
   btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs]
   btrfs_ioctl+0x11a4/0x2da0 [btrfs]
   do_vfs_ioctl+0xa9/0x640
   ksys_ioctl+0x67/0x90
   __x64_sys_ioctl+0x1a/0x20
   do_syscall_64+0x5a/0x110
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 33f2f83f3d5250e9 ]---
  BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown
  BTRFS info (device sda1): forced readonly
  BTRFS warning (device sda1): Skipping commit of aborted transaction.
  BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown

[CAUSE]
When the global anonymous block device pool is exhausted, the following
call chain will fail, and lead to transaction abort:

 btrfs_ioctl_snap_create_v2()
 |- btrfs_ioctl_snap_create_transid()
    |- btrfs_mksubvol()
       |- btrfs_commit_transaction()
          |- create_pending_snapshot()
             |- btrfs_get_fs_root()
                |- btrfs_init_fs_root()
                   |- get_anon_bdev()

[FIX]
Although we can't enlarge the anonymous block device pool, at least we
can preallocate anon_dev for subvolume/snapshot in the first phase,
outside of transaction context and exactly at the moment the user calls
the creation ioctl.

Reported-by: Greed Rong <greedrong@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:38 +02:00
Qu Wenruo
082b6c970f btrfs: free anon block device right after subvolume deletion
[BUG]
When a lot of subvolumes are created, there is a user report about
transaction aborted caused by slow anonymous block device reclaim:

  BTRFS: Transaction aborted (error -24)
  WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs]
  RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs]
  Call Trace:
   create_pending_snapshots+0x82/0xa0 [btrfs]
   btrfs_commit_transaction+0x275/0x8c0 [btrfs]
   btrfs_mksubvol+0x4b9/0x500 [btrfs]
   btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs]
   btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs]
   btrfs_ioctl+0x11a4/0x2da0 [btrfs]
   do_vfs_ioctl+0xa9/0x640
   ksys_ioctl+0x67/0x90
   __x64_sys_ioctl+0x1a/0x20
   do_syscall_64+0x5a/0x110
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 33f2f83f3d5250e9 ]---
  BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown
  BTRFS info (device sda1): forced readonly
  BTRFS warning (device sda1): Skipping commit of aborted transaction.
  BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown

[CAUSE]
The anonymous device pool is shared and its size is 1M. It's possible to
hit that limit if the subvolume deletion is not fast enough and the
subvolumes to be cleaned keep the ids allocated.

[WORKAROUND]
We can't avoid the anon device pool exhaustion but we can shorten the
time the id is attached to the subvolume root once the subvolume becomes
invisible to the user.

Reported-by: Greed Rong <greedrong@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:38 +02:00
Qu Wenruo
851fd730a7 btrfs: don't allocate anonymous block device for user invisible roots
[BUG]
When a lot of subvolumes are created, there is a user report about
transaction aborted:

  BTRFS: Transaction aborted (error -24)
  WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs]
  RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs]
  Call Trace:
   create_pending_snapshots+0x82/0xa0 [btrfs]
   btrfs_commit_transaction+0x275/0x8c0 [btrfs]
   btrfs_mksubvol+0x4b9/0x500 [btrfs]
   btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs]
   btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs]
   btrfs_ioctl+0x11a4/0x2da0 [btrfs]
   do_vfs_ioctl+0xa9/0x640
   ksys_ioctl+0x67/0x90
   __x64_sys_ioctl+0x1a/0x20
   do_syscall_64+0x5a/0x110
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 33f2f83f3d5250e9 ]---
  BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown
  BTRFS info (device sda1): forced readonly
  BTRFS warning (device sda1): Skipping commit of aborted transaction.
  BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown

[CAUSE]
The error is EMFILE (Too many files open) and comes from the anonymous
block device allocation. The ids are in a shared pool of size 1<<20.

The ids are assigned to live subvolumes, ie. the root structure exists
in memory (eg. after creation or after the root appears in some path).
The pool could be exhausted if the numbers are not reclaimed fast
enough, after subvolume deletion or if other system component uses the
anon block devices.

[WORKAROUND]
Since it's not possible to completely solve the problem, we can only
minimize the time the id is allocated to a subvolume root.

Firstly, we can reduce the use of anon_dev by trees that are not
subvolume roots, like data reloc tree.

This patch will do extra check on root objectid, to skip roots that
don't need anon_dev.  Currently it's only data reloc tree and orphan
roots.

Reported-by: Greed Rong <greedrong@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:38 +02:00
Qu Wenruo
49e5fb4621 btrfs: qgroup: export qgroups in sysfs
This patch will add the following sysfs interface:

  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/referenced
  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/exclusive
  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/max_referenced
  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/max_exclusive
  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/limit_flags

Which is also available in output of "btrfs qgroup show".

  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/rsv_data
  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/rsv_meta_pertrans
  /sys/fs/btrfs/<UUID>/qgroups/<qgroup_id>/rsv_meta_prealloc

The last 3 rsv related members are not visible to users, but can be very
useful to debug qgroup limit related bugs.

Also, to avoid '/' used in <qgroup_id>, the separator between qgroup
level and qgroup id is changed to '_'.

The interface is not hidden behind 'debug' as we want this interface to
be included into production build and to provide another way to read the
qgroup information besides the ioctls.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:37 +02:00
Qu Wenruo
06f67c4707 btrfs: use __u16 for the return value of btrfs_qgroup_level()
The qgroup level is limited to u16, so no need to use u64 for it.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:37 +02:00
Nikolay Borisov
cfdd459215 btrfs: make btrfs_qgroup_check_reserved_leak take btrfs_inode
vfs_inode is used only for the inode number everything else requires
btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ use btrfs_ino ]
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:37 +02:00
Nikolay Borisov
d90944141b btrfs: make btrfs_set_inode_last_trans take btrfs_inode
Instead of making multiple calls to BTRFS_I simply take btrfs_inode as
an input paramter.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:37 +02:00
Nikolay Borisov
056d9beca3 btrfs: make prealloc_file_extent_cluster take btrfs_inode
The vfs inode is only used for a pair of inode_lock/unlock calls all
other uses call for btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:37 +02:00
Nikolay Borisov
65d87f7918 btrfs: remove BTRFS_I calls in btrfs_writepage_fixup_worker
All of its children functions use btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:36 +02:00
Nikolay Borisov
e5b7231e20 btrfs: make btrfs_delalloc_reserve_space take btrfs_inode
All of its children take btrfs_inode so bubble up this requirement to
btrfs_delalloc_reserve_space's interface and stop calling BTRFS_I
internally.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:36 +02:00
Nikolay Borisov
36ea6f3e93 btrfs: make btrfs_check_data_free_space take btrfs_inode
Instead of calling BTRFS_I on the passed vfs_inode take btrfs_inode
directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:36 +02:00
Nikolay Borisov
86d52921a2 btrfs: make btrfs_delalloc_release_space take btrfs_inode
It needs btrfs_inode so take it as a parameter directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:36 +02:00
Nikolay Borisov
25ce28caaa btrfs: make btrfs_free_reserved_data_space take btrfs_inode
It only uses btrfs_inode internally so take it as a parameter.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:36 +02:00
Nikolay Borisov
9db5d510ac btrfs: make btrfs_free_reserved_data_space_noquota take btrfs_fs_info
No point in taking an inode only to get btrfs_fs_info from it, instead
take btrfs_fs_info directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:35 +02:00
Nikolay Borisov
7661a3e033 btrfs: make btrfs_qgroup_reserve_data take btrfs_inode
There's only a single use of vfs_inode in a tracepoint so let's take
btrfs_inode directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:35 +02:00
Nikolay Borisov
088545f6e4 btrfs: make btrfs_dirty_pages take btrfs_inode
There is a single use of the generic vfs_inode so let's take btrfs_inode
as a parameter and remove couple of redundant BTRFS_I() calls.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:35 +02:00
Nikolay Borisov
c2566f2289 btrfs: make btrfs_set_extent_delalloc take btrfs_inode
Preparation to make btrfs_dirty_pages take btrfs_inode as parameter.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:35 +02:00
Nikolay Borisov
cd4c0bf942 btrfs: make writepage_delalloc take btrfs_inode
Only find_lock_delalloc_range uses vfs_inode so let's take the
btrfs_inode as a parameter.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:35 +02:00
Nikolay Borisov
d4580fe25d btrfs: make __extent_writepage_io take btrfs_inode
It has only a single use for a generic vfs inode vs 3 for btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:34 +02:00
Nikolay Borisov
9fc6f911a0 btrfs: make btrfs_new_extent_direct take btrfs_inode
This function really needs a btrfs_inode and not a generic vfs one. Take
it as a parameter and get rid of superfluous BTRFS_I() calls.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:34 +02:00
Nikolay Borisov
64f54188ea btrfs: make btrfs_create_dio_extent take btrfs_inode
Take btrfs_inode directly and stop using superfulous BTRFS_I calls.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:34 +02:00
Nikolay Borisov
c1e095202c btrfs: make btrfs_add_ordered_extent_dio take btrfs_inode
Simply forwards its argument so let's get rid of one extra BTRFS_I by
taking btrfs_inode directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:34 +02:00
Nikolay Borisov
98456b9c46 btrfs: make btrfs_run_delalloc_range take btrfs_inode
All children now take btrfs_inode so convert it to taking it as a
parameter as well.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:34 +02:00
Nikolay Borisov
0c4942258c btrfs: make need_force_cow take btrfs_inode
Gets rid of superfulous BTRFS_I() calls and prepare for converting
btrfs_run_delalloc_range to using btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:34 +02:00
Nikolay Borisov
808a129232 btrfs: make inode_need_compress take btrfs_inode
Simply gets rid of superfluous BTRFS_I() calls.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:33 +02:00
Nikolay Borisov
99c88dc71c btrfs: make inode_can_compress take btrfs_inode
Gets rid of superfluous BTRFS_I() calls.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:33 +02:00
Nikolay Borisov
64e1db566d btrfs: make btrfs_cleanup_ordered_extents take btrfs_inode
Preparation to converting btrfs_run_delalloc_range to using btrfs_inode
without BTRFS_I() calls.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:33 +02:00
Nikolay Borisov
b672b5c156 btrfs: make __endio_write_update_ordered take btrfs_inode
It really wants btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:33 +02:00
Nikolay Borisov
7095821ee1 btrfs: make btrfs_dec_test_first_ordered_pending take btrfs_inode
It doesn't really need vfs_inode but btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:33 +02:00
Nikolay Borisov
751b64318d btrfs: make cow_file_range_async take btrfs_inode
It only uses vfs inode for assigning it to the async_chunk function.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:32 +02:00
Nikolay Borisov
968322c8c6 btrfs: make run_delalloc_nocow take btrfs_inode
It only really uses btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:32 +02:00
Nikolay Borisov
8ba96f3dd6 btrfs: make fallback_to_cow take btrfs_inode
It really wants btrfs_inode and is prepration to converting
run_delalloc_nocow to taking btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:32 +02:00
Nikolay Borisov
c553f94df4 btrfs: make insert_reserved_file_extent take btrfs_inode
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>c
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:32 +02:00
Nikolay Borisov
72b7d15bf1 btrfs: make btrfs_qgroup_release_data take btrfs_inode
It just forwards its argument to __btrfs_qgroup_release_data.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:32 +02:00
Nikolay Borisov
a0ff10dcc4 btrfs: make submit_compressed_extents take btrfs_inode
All but 3 uses require vfs_inode so convert the logic to have
btrfs_inode be the main inode struct.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:31 +02:00
Nikolay Borisov
c7ee1819dc btrfs: make btrfs_submit_compressed_write take btrfs_inode
Majority of its uses are for btrfs_inode so take it as an argument
directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:31 +02:00
Nikolay Borisov
4cc612090b btrfs: make btrfs_add_ordered_extent_compress take btrfs_inode
It simpy forwards its inode argument to __btrfs_add_ordered_extent which
already takes btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:31 +02:00
Nikolay Borisov
6e26c44223 btrfs: make cow_file_range take btrfs_inode
All its children functions take btrfs_inode so convert it to taking
btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:31 +02:00
Nikolay Borisov
e7fbf60453 btrfs: make btrfs_add_ordered_extent take btrfs_inode
Preparation to converting its callers to taking btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:31 +02:00
Nikolay Borisov
a0349401c1 btrfs: make cow_file_range_inline take btrfs_inode
It has only 2 uses for the vfs_inode - insert_inline_extent and
i_size_read.  On the flipside it will allow converting its callers to
btrfs_inode, so convert it to taking btrfs_inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:30 +02:00
Nikolay Borisov
8b8a979f1f btrfs: make btrfs_qgroup_free_data take btrfs_inode
It passes btrfs_inode to its callee so change the interface.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:30 +02:00
Nikolay Borisov
8769af96cf btrfs: make __btrfs_qgroup_release_data take btrfs_inode
It uses vfs_inode only for a tracepoint so convert its interface to take
btrfs_inode directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:30 +02:00
Nikolay Borisov
df2cfd131f btrfs: make qgroup_free_reserved_data take btrfs_inode
It only uses btrfs_inode so can just as easily take it as an argument.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:30 +02:00
David Sterba
3502a8c0dc btrfs: allow use of global block reserve for balance item deletion
On a filesystem with exhausted metadata, but still enough to start
balance, it's possible to hit this error:

[324402.053842] BTRFS info (device loop0): 1 enospc errors during balance
[324402.060769] BTRFS info (device loop0): balance: ended with status: -28
[324402.172295] BTRFS: error (device loop0) in reset_balance_state:3321: errno=-28 No space left

It fails inside reset_balance_state and turns the filesystem to
read-only, which is unnecessary and should be fixed too, but the problem
is caused by lack for space when the balance item is deleted. This is a
one-time operation and from the same rank as unlink that is allowed to
use the global block reserve. So do the same for the balance item.

Status of the filesystem (100GiB) just after the balance fails:

$ btrfs fi df mnt
Data, single: total=80.01GiB, used=38.58GiB
System, single: total=4.00MiB, used=16.00KiB
Metadata, single: total=19.99GiB, used=19.48GiB
GlobalReserve, single: total=512.00MiB, used=50.11MiB

CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:29 +02:00
Qu Wenruo
38d37aa9c3 btrfs: refactor btrfs_check_can_nocow() into two variants
The function btrfs_check_can_nocow() now has two completely different
call patterns.

For nowait variant, callers don't need to do any cleanup.  While for
wait variant, callers need to release the lock if they can do nocow
write.

This is somehow confusing, and is already a problem for the exported
btrfs_check_can_nocow().

So this patch will separate the different patterns into different
functions.
For nowait variant, the function will be called check_nocow_nolock().
For wait variant, the function pair will be btrfs_check_nocow_lock()
btrfs_check_nocow_unlock().

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:28 +02:00
Qu Wenruo
e4ecaf90bc btrfs: add comments for btrfs_check_can_nocow() and can_nocow_extent()
These two functions have extra conditions that their callers need to
meet, and some not-that-common parameters used for return value.

So adding some comments may save reviewers some time.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:28 +02:00
Qu Wenruo
6d4572a9d7 btrfs: allow btrfs_truncate_block() to fallback to nocow for data space reservation
[BUG]
When the data space is exhausted, even if the inode has NOCOW attribute,
we will still refuse to truncate unaligned range due to ENOSPC.

The following script can reproduce it pretty easily:
  #!/bin/bash

  dev=/dev/test/test
  mnt=/mnt/btrfs

  umount $dev &> /dev/null
  umount $mnt &> /dev/null

  mkfs.btrfs -f $dev -b 1G
  mount -o nospace_cache $dev $mnt
  touch $mnt/foobar
  chattr +C $mnt/foobar

  xfs_io -f -c "pwrite -b 4k 0 4k" $mnt/foobar > /dev/null
  xfs_io -f -c "pwrite -b 4k 0 1G" $mnt/padding &> /dev/null
  sync

  xfs_io -c "fpunch 0 2k" $mnt/foobar
  umount $mnt

Currently this will fail at the fpunch part.

[CAUSE]
Because btrfs_truncate_block() always reserves space without checking
the NOCOW attribute.

Since the writeback path follows NOCOW bit, we only need to bother the
space reservation code in btrfs_truncate_block().

[FIX]
Make btrfs_truncate_block() follow btrfs_buffered_write() to try to
reserve data space first, and fall back to NOCOW check only when we
don't have enough space.

Such always-try-reserve is an optimization introduced in
btrfs_buffered_write(), to avoid expensive btrfs_check_can_nocow() call.

This patch will export check_can_nocow() as btrfs_check_can_nocow(), and
use it in btrfs_truncate_block() to fix the problem.

Reported-by: Martin Doucha <martin.doucha@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:28 +02:00
David Sterba
b547a88ea5 btrfs: start deprecation of mount option inode_cache
Estimated time of removal of the functionality is 5.11, the option will
be still parsed but will have no effect.

Reasons for deprecation and removal:

- very poor naming choice of the mount option, it's supposed to cache
  and reuse the inode _numbers_, but it sounds a some generic cache for
  inodes

- the only known usecase where this option would make sense is on a
  32bit architecture where inode numbers in one subvolume would be
  exhausted due to 32bit inode::i_ino

- the cache is stored on disk, consumes space, needs to be loaded and
  written back

- new inode number allocation is slower due to lookups into the cache
  (compared to a simple increment which is the default)

- uses the free-space-cache code that is going to be deprecated as well
  in the future

Known problems:

- since 2011, returning EEXIST when there's not enough space in a page
  to store all checksums, see commit 4b9465cb9e ("Btrfs: add mount -o
  inode_cache")

Remaining issues:

- if the option was enabled, new inodes created, the option disabled
  again, the cache is still stored on the devices and there's currently
  no way to remove it

Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:28 +02:00
David Sterba
a2570ef330 btrfs: remove unused btrfs_root::defrag_trans_start
Last touched in 2013 by commit de78b51a28 ("btrfs: remove cache only
arguments from defrag path") that was the only code that used the value.
Now it's only set but never used for anything, so we can remove it.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:28 +02:00
David Sterba
bab16e21e8 btrfs: don't use UAPI types for fiemap callback
The fiemap callback is not part of UAPI interface and the prototypes
don't have the __u64 types either.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:27 +02:00
Denis Efremov
5af9d6ef3f btrfs: tests: remove if duplicate in __check_free_space_extents()
num_extents is already checked in the next if condition and can
be safely removed.

Signed-off-by: Denis Efremov <efremov@linux.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:27 +02:00
Johannes Thumshirn
923eb52365 btrfs: use free_root_extent_buffer to free root
In btrfs_put_root() we're freeing a btrfs_root's 'node' and 'commit_root'
extent buffers manually via kfree(), while we're using
free_root_extent_buffers() in the free_root_pointers() function above.

free_root_extent_buffers() also NULLs the pointers after freeing, which
mitigates potential double frees.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:27 +02:00
Nikolay Borisov
4e9d0d0109 btrfs: use for loop in prealloc_file_extent_cluster
This function iterates all extents in the extent cluster, make this
intention obvious by using a for loop. No functional chanes.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:27 +02:00
Nikolay Borisov
214e61d07e btrfs: perform data management operations outside of inode lock
btrfs_alloc_data_chunk_ondemand and btrfs_free_reserved_data_space_noquota
don't really use the guts of the inodes being passed to them. This
implies it's not required to call them under extent lock. Move code
around in prealloc_file_extent_cluster to do the heavy, data alloc/free
operations outside of the lock. This also makes the 'out' label
unnecessary, so remove it.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:27 +02:00
Nikolay Borisov
c171edd5c8 btrfs: remove hole check in prealloc_file_extent_cluster
Extents in the extent cluster are guaranteed to be contiguous as such
the hole check inside the loop can never trigger. In fact this check was
never functional since it was added in 18513091af ("btrfs: update
btrfs_space_info's bytes_may_use timely") which came after the commit
introducing clustered/contiguous extents 0257bb82d2 ("Btrfs: relocate
file extents in clusters").

Let's just remove it as it adds noise to the source.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:27 +02:00
Nikolay Borisov
906c448c3d btrfs: make __btrfs_drop_extents take btrfs_inode
It has only 4 uses of a vfs_inode for inode_sub_bytes but unifies the
interface with the non  __ prefixed version. Will also makes converting
its callers to btrfs_inode easier.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:26 +02:00
Nikolay Borisov
bd242a08a6 btrfs: make btrfs_csum_one_bio takae btrfs_inode
Will enable converting btrfs_submit_compressed_write to btrfs_inode more
easily.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:26 +02:00
Nikolay Borisov
ad7ff17b65 btrfs: make extent_clear_unlock_delalloc take btrfs_inode
It has one VFS and 1 btrfs inode usages but converting it to btrfs_inode
interface will allow seamless conversion of its callers.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:26 +02:00
Nikolay Borisov
4b67c11dd1 btrfs: make create_io_em take btrfs_inode
It really wants a btrfs_inode and will allow submit_compressed_extents
to be completely converted to btrfs_inode in follow up patches.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:26 +02:00
Nikolay Borisov
7bfa953501 btrfs: make btrfs_reloc_clone_csums take btrfs_inode
It really wants btrfs_inode and not a vfs inode.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:26 +02:00
Nikolay Borisov
c350437269 btrfs: make btrfs_lookup_ordered_extent take btrfs_inode
It doesn't use the generic vfs inode for anything use btrfs_inode
directly.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:25 +02:00
Nikolay Borisov
43c69849ae btrfs: make get_extent_allocation_hint take btrfs_inode
It doesn't use the vfs inode for anything, can just as easily take
btrfs_inode.  Follow up patches will convert callers as well.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:25 +02:00
Nikolay Borisov
da69fea9f7 btrfs: make __btrfs_add_ordered_extent take struct btrfs_inode
This is internal btrfs function what really needs the vfs_inode only for
igrab and a tracepoint.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:25 +02:00
Filipe Manana
3ef64143a7 btrfs: remove no longer used trans_list member of struct btrfs_ordered_extent
The 'trans_list' member of an ordered extent was used to keep track of the
ordered extents for which a transaction commit had to wait. These were
ordered extents that were started and logged by an fsync. However we don't
do that anymore and before we stopped doing it we changed the approach to
wait for the ordered extents in commit 161c3549b4 ("Btrfs: change how
we wait for pending ordered extents"), which stopped using that list and
therefore the 'trans_list' member is not used anymore since that commit.
So just remove it since it's doing nothing and making each ordered extent
structure waste memory (2 pointers).

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:25 +02:00
Filipe Manana
cd8d39f4ae btrfs: remove no longer used log_list member of struct btrfs_ordered_extent
The 'log_list' member of an ordered extent was used keep track of which
ordered extents we needed to wait after logging metadata, but is not used
anymore since commit 5636cf7d6d ("btrfs: remove the logged extents
infrastructure"), as we now always wait on ordered extent completion
before logging metadata. So just remove it since it's doing nothing and
making each ordered extent structure waste more memory (2 pointers).

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:25 +02:00
David Sterba
ce6ef5abe6 btrfs: add little-endian optimized key helpers
The CPU and on-disk keys are mapped to two different structures because
of the endianness. There's an intermediate buffer used to do the
conversion, but this is not necessary when CPU and on-disk endianness
match.

Add optimized versions of helpers that take disk_key and use the buffer
directly for CPU keys or drop the intermediate buffer and conversion.

This saves a lot of stack space accross many functions and removes about
6K of generated binary code:

   text    data     bss     dec     hex filename
1090439   17468   14912 1122819  112203 pre/btrfs.ko
1084613   17456   14912 1116981  110b35 post/btrfs.ko

Delta: -5826

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:24 +02:00
Qu Wenruo
5958253cf6 btrfs: qgroup: catch reserved space leaks at unmount time
Before this patch, qgroup completely relies on per-inode extent io tree
to detect reserved data space leak.

However previous bug has already shown how release page before
btrfs_finish_ordered_io() could lead to leak, and since it's
QGROUP_RESERVED bit cleared without triggering qgroup rsv, it can't be
detected by per-inode extent io tree.

So this patch adds another (and hopefully the final) safety net to catch
qgroup data reserved space leak.  At least the new safety net catches
all the leaks during development, so it should be pretty useful in the
real world.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:24 +02:00
Qu Wenruo
7dbeaad0af btrfs: change timing for qgroup reserved space for ordered extents to fix reserved space leak
[BUG]
The following simple workload from fsstress can lead to qgroup reserved
data space leak:
  0/0: creat f0 x:0 0 0
  0/0: creat add id=0,parent=-1
  0/1: write f0[259 1 0 0 0 0] [600030,27288] 0
  0/4: dwrite - xfsctl(XFS_IOC_DIOINFO) f0[259 1 0 0 64 627318] return 25, fallback to stat()
  0/4: dwrite f0[259 1 0 0 64 627318] [610304,106496] 0

This would cause btrfs qgroup to leak 20480 bytes for data reserved
space.  If btrfs qgroup limit is enabled, such leak can lead to
unexpected early EDQUOT and unusable space.

[CAUSE]
When doing direct IO, kernel will try to writeback existing buffered
page cache, then invalidate them:
  generic_file_direct_write()
  |- filemap_write_and_wait_range();
  |- invalidate_inode_pages2_range();

However for btrfs, the bi_end_io hook doesn't finish all its heavy work
right after bio ends.  In fact, it delays its work further:

  submit_extent_page(end_io_func=end_bio_extent_writepage);
  end_bio_extent_writepage()
  |- btrfs_writepage_endio_finish_ordered()
     |- btrfs_init_work(finish_ordered_fn);

  <<< Work queue execution >>>
  finish_ordered_fn()
  |- btrfs_finish_ordered_io();
     |- Clear qgroup bits

This means, when filemap_write_and_wait_range() returns,
btrfs_finish_ordered_io() is not guaranteed to be executed, thus the
qgroup bits for related range are not cleared.

Now into how the leak happens, this will only focus on the overlapping
part of buffered and direct IO part.

1. After buffered write
   The inode had the following range with QGROUP_RESERVED bit:
   	596		616K
	|///////////////|
   Qgroup reserved data space: 20K

2. Writeback part for range [596K, 616K)
   Write back finished, but btrfs_finish_ordered_io() not get called
   yet.
   So we still have:
   	596K		616K
	|///////////////|
   Qgroup reserved data space: 20K

3. Pages for range [596K, 616K) get released
   This will clear all qgroup bits, but don't update the reserved data
   space.
   So we have:
   	596K		616K
	|		|
   Qgroup reserved data space: 20K
   That number doesn't match the qgroup bit range anymore.

4. Dio prepare space for range [596K, 700K)
   Qgroup reserved data space for that range, we got:
   	596K		616K			700K
	|///////////////|///////////////////////|
   Qgroup reserved data space: 20K + 104K = 124K

5. btrfs_finish_ordered_range() gets executed for range [596K, 616K)
   Qgroup free reserved space for that range, we got:
   	596K		616K			700K
	|		|///////////////////////|
   We need to free that range of reserved space.
   Qgroup reserved data space: 124K - 20K = 104K

6. btrfs_finish_ordered_range() gets executed for range [596K, 700K)
   However qgroup bit for range [596K, 616K) is already cleared in
   previous step, so we only free 84K for qgroup reserved space.
   	596K		616K			700K
	|		|			|
   We need to free that range of reserved space.
   Qgroup reserved data space: 104K - 84K = 20K

   Now there is no way to release that 20K unless disabling qgroup or
   unmounting the fs.

[FIX]
This patch will change the timing of btrfs_qgroup_release/free_data()
call.  Here it uses buffered COW write as an example.

	The new timing			|	The old timing
----------------------------------------+---------------------------------------
 btrfs_buffered_write()			| btrfs_buffered_write()
 |- btrfs_qgroup_reserve_data() 	| |- btrfs_qgroup_reserve_data()
					|
 btrfs_run_delalloc_range()		| btrfs_run_delalloc_range()
 |- btrfs_add_ordered_extent()  	|
    |- btrfs_qgroup_release_data()	|
       The reserved is passed into	|
       btrfs_ordered_extent structure	|
					|
 btrfs_finish_ordered_io()		| btrfs_finish_ordered_io()
 |- The reserved space is passed to 	| |- btrfs_qgroup_release_data()
    btrfs_qgroup_record			|    The resereved space is passed
					|    to btrfs_qgroup_recrod
					|
 btrfs_qgroup_account_extents()		| btrfs_qgroup_account_extents()
 |- btrfs_qgroup_free_refroot()		| |- btrfs_qgroup_free_refroot()

The point of such change is to ensure, when ordered extents are
submitted, the qgroup reserved space is already released, to keep the
timing aligned with file_write_and_wait_range().

So that qgroup data reserved space is all bound to btrfs_ordered_extent
and solve the timing mismatch.

Fixes: f695fdcef8 ("btrfs: qgroup: Introduce functions to release/free qgroup reserve data space")
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:24 +02:00
Qu Wenruo
a7f8b1c2ac btrfs: file: reserve qgroup space after the hole punch range is locked
The incoming qgroup reserved space timing will move the data reservation
to ordered extent completely.

However in btrfs_punch_hole_lock_range() will call
btrfs_invalidate_page(), which will clear QGROUP_RESERVED bit for the
range.

In current stage it's OK, but if we're making ordered extents handle the
reserved space, then btrfs_punch_hole_lock_range() can clear the
QGROUP_RESERVED bit before we submit ordered extent, leading to qgroup
reserved space leakage.

So here change the timing to make reserve data space after
btrfs_punch_hole_lock_range().
The new timing is fine for either current code or the new code.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:24 +02:00
Qu Wenruo
9729f10a60 btrfs: inode: move qgroup reserved space release to the callers of insert_reserved_file_extent()
This is to prepare for the incoming timing change of qgroup reserved
data space and ordered extent.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:24 +02:00
Qu Wenruo
203f44c519 btrfs: inode: refactor the parameters of insert_reserved_file_extent()
Function insert_reserved_file_extent() takes a long list of parameters,
which are all for btrfs_file_extent_item, even including two reserved
members, encryption and other_encoding.

This makes the parameter list unnecessary long for a function which only
gets called twice.

This patch will refactor the parameter list, by using
btrfs_file_extent_item as parameter directly to hugely reduce the number
of parameters.

Also, since there are only two callers, one in btrfs_finish_ordered_io()
which inserts file extent for ordered extent, and one
__btrfs_prealloc_file_range().

These two call sites have completely different context, where ordered
extent can be compressed, but will always be regular extent, while the
preallocated one is never going to be compressed and always has PREALLOC
type.

So use two small wrapper for these two different call sites to improve
readability.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:23 +02:00