Commit Graph

8352 Commits

Author SHA1 Message Date
Qu Wenruo
3296bf5624 btrfs: transaction: Cleanup unused TRANS_STATE_BLOCKED
The state was introduced in commit 4a9d8bdee3 ("Btrfs: make the state
of the transaction more readable"), then in commit 302167c50b
("btrfs: don't end the transaction for delayed refs in throttle") the
state is completely removed.

So we can just clean up the state since it's only compared but never
set.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:50 +01:00
Qu Wenruo
61c047b541 btrfs: transaction: describe transaction states and transitions
Add an overview of the basic btrfs transaction transitions, including
the following states:

- No transaction states
- Transaction N [[TRANS_STATE_RUNNING]]
- Transaction N [[TRANS_STATE_COMMIT_START]]
- Transaction N [[TRANS_STATE_COMMIT_DOING]]
- Transaction N [[TRANS_STATE_UNBLOCKED]]
- Transaction N [[TRANS_STATE_COMPLETED]]

For each state, the comment will include:

- Basic explaination about current state
- How to go next stage
- What will happen if we call various start_transaction() functions
- Relationship to transaction N+1

This doesn't provide tech details, but serves as a cheat sheet for
reader to get into the code a little easier.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:50 +01:00
David Sterba
c1499166d1 btrfs: use has_single_bit_set for clarity
Replace is_power_of_2 with the helper that is self-documenting and
remove the open coded call in alloc_profile_is_valid.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:50 +01:00
David Sterba
79c8264e44 btrfs: add 64bit safe helper for power of two checks
As is_power_of_two takes unsigned long, it's not safe on 32bit
architectures, but we could pass any u64 value in seveal places. Add a
separate helper and also an alias that better expresses the purpose for
which the helper is used.

Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:50 +01:00
Anand Jain
e62869be1e btrfs: balance: use term redundancy instead of integrity in message
When balance reduces the number of copies of metadata, it reduces the
redundancy, use the term redundancy instead of integrity.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:50 +01:00
David Sterba
1f95ec012c btrfs: move btrfs_unlock_up_safe to other locking functions
The function belongs to the family of locking functions, so move it
there. The 'noinline' keyword is dropped as it's now an exported
function that does not need it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:49 +01:00
David Sterba
ed2b1d36a9 btrfs: move btrfs_set_path_blocking to other locking functions
The function belongs to the family of locking functions, so move it
there. The 'noinline' keyword is dropped as it's now an exported
function that does not need it.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:49 +01:00
David Sterba
31f6e769ce btrfs: make btrfs_assert_tree_locked static inline
The function btrfs_assert_tree_locked is used outside of the locking
code so it is exported, however we can make it static inine as it's
fairly trivial.

This is the only locking assertion used in release builds, inlining
improves the text size by 174 bytes and reduces stack consumption in the
callers.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:49 +01:00
David Sterba
d6156218be btrfs: make locking assertion helpers static inline
I've noticed that none of the btrfs_assert_*lock* debugging helpers is
inlined, despite they're short and mostly a value update. Making them
inline shaves 67 from the text size, reduces stack consumption and
perhaps also slightly improves the performance due to avoiding
unnecessary calls.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:49 +01:00
Omar Sandoval
c9eb55db84 btrfs: get rid of pointless wtag variable in async-thread.c
Commit ac0c7cf8be ("btrfs: fix crash when tracepoint arguments are
freed by wq callbacks") added a void pointer, wtag, which is passed into
trace_btrfs_all_work_done() instead of the freed work item. This is
silly for a few reasons:

1. The freed work item still has the same address.
2. work is still in scope after it's freed, so assigning wtag doesn't
   stop anyone from using it.
3. The tracepoint has always taken a void * argument, so assigning wtag
   doesn't actually make things any more type-safe. (Note that the
   original bug in commit bc074524e1 ("btrfs: prefix fsid to all trace
   events") was that the void * was implicitly casted when it was passed
   to btrfs_work_owner() in the trace point itself).

Instead, let's add some clearer warnings as comments.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:49 +01:00
Omar Sandoval
a0cac0ec96 btrfs: get rid of unique workqueue helper functions
Commit 9e0af23764 ("Btrfs: fix task hang under heavy compressed
write") worked around the issue that a recycled work item could get a
false dependency on the original work item due to how the workqueue code
guarantees non-reentrancy. It did so by giving different work functions
to different types of work.

However, the fixes in the previous few patches are more complete, as
they prevent a work item from being recycled at all (except for a tiny
window that the kernel workqueue code handles for us). This obsoletes
the previous fix, so we don't need the unique helpers for correctness.
The only other reason to keep them would be so they show up in stack
traces, but they always seem to be optimized to a tail call, so they
don't show up anyways. So, let's just get rid of the extra indirection.

While we're here, rename normal_work_helper() to the more informative
btrfs_work_helper().

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:48 +01:00
Omar Sandoval
57d4f0b863 btrfs: don't prematurely free work in scrub_missing_raid56_worker()
Currently, scrub_missing_raid56_worker() puts and potentially frees
sblock (which embeds the work item) and then submits a bio through
scrub_wr_submit(). This is another potential instance of the bug in
"btrfs: don't prematurely free work in run_ordered_work()". Fix it by
dropping the reference after we submit the bio.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:48 +01:00
Omar Sandoval
e732fe95e4 btrfs: don't prematurely free work in reada_start_machine_worker()
Currently, reada_start_machine_worker() frees the reada_machine_work and
then calls __reada_start_machine() to do readahead. This is another
potential instance of the bug in "btrfs: don't prematurely free work in
run_ordered_work()".

There _might_ already be a deadlock here: reada_start_machine_worker()
can depend on itself through stacked filesystems (__read_start_machine()
-> reada_start_machine_dev() -> reada_tree_block_flagged() ->
read_extent_buffer_pages() -> submit_one_bio() ->
btree_submit_bio_hook() -> btrfs_map_bio() -> submit_stripe_bio() ->
submit_bio() onto a loop device can trigger readahead on the lower
filesystem).

Either way, let's fix it by freeing the work at the end.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:48 +01:00
Omar Sandoval
9be490f1e1 btrfs: don't prematurely free work in end_workqueue_fn()
Currently, end_workqueue_fn() frees the end_io_wq entry (which embeds
the work item) and then calls bio_endio(). This is another potential
instance of the bug in "btrfs: don't prematurely free work in
run_ordered_work()".

In particular, the endio call may depend on other work items. For
example, btrfs_end_dio_bio() can call btrfs_subio_endio_read() ->
__btrfs_correct_data_nocsum() -> dio_read_error() ->
submit_dio_repair_bio(), which submits a bio that is also completed
through a end_workqueue_fn() work item. However,
__btrfs_correct_data_nocsum() waits for the newly submitted bio to
complete, thus it depends on another work item.

This example currently usually works because we use different workqueue
helper functions for BTRFS_WQ_ENDIO_DATA and BTRFS_WQ_ENDIO_DIO_REPAIR.
However, it may deadlock with stacked filesystems and is fragile
overall. The proper fix is to free the work item at the very end of the
work function, so let's do that.

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:48 +01:00
Omar Sandoval
c495dcd6fb btrfs: don't prematurely free work in run_ordered_work()
We hit the following very strange deadlock on a system with Btrfs on a
loop device backed by another Btrfs filesystem:

1. The top (loop device) filesystem queues an async_cow work item from
   cow_file_range_async(). We'll call this work X.
2. Worker thread A starts work X (normal_work_helper()).
3. Worker thread A executes the ordered work for the top filesystem
   (run_ordered_work()).
4. Worker thread A finishes the ordered work for work X and frees X
   (work->ordered_free()).
5. Worker thread A executes another ordered work and gets blocked on I/O
   to the bottom filesystem (still in run_ordered_work()).
6. Meanwhile, the bottom filesystem allocates and queues an async_cow
   work item which happens to be the recently-freed X.
7. The workqueue code sees that X is already being executed by worker
   thread A, so it schedules X to be executed _after_ worker thread A
   finishes (see the find_worker_executing_work() call in
   process_one_work()).

Now, the top filesystem is waiting for I/O on the bottom filesystem, but
the bottom filesystem is waiting for the top filesystem to finish, so we
deadlock.

This happens because we are breaking the workqueue assumption that a
work item cannot be recycled while it still depends on other work. Fix
it by waiting to free the work item until we are done with all of the
related ordered work.

P.S.:

One might ask why the workqueue code doesn't try to detect a recycled
work item. It actually does try by checking whether the work item has
the same work function (find_worker_executing_work()), but in our case
the function is the same. This is the only key that the workqueue code
has available to compare, short of adding an additional, layer-violating
"custom key". Considering that we're the only ones that have ever hit
this, we should just play by the rules.

Unfortunately, we haven't been able to create a minimal reproducer other
than our full container setup using a compress-force=zstd filesystem on
top of another compress-force=zstd filesystem.

Suggested-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:48 +01:00
Omar Sandoval
cdc6f1668e btrfs: get rid of unnecessary memset() of work item
Commit fc97fab0ea ("btrfs: Replace fs_info->qgroup_rescan_worker
workqueue with btrfs_workqueue.") converted qgroup_rescan_work to be
initialized with btrfs_init_work(), but it left behind an unnecessary
memset(). Get rid of the memset().

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:47 +01:00
Josef Bacik
b3f167aa6c btrfs: move the failrec tree stuff into extent-io-tree.h
This needs to be cleaned up in the future, but for now it belongs to the
extent-io-tree stuff since it uses the internal tree search code.
Needed to export get_state_failrec and set_state_failrec as well since
we're not going to move the actual IO part of the failrec stuff out at
this point.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:47 +01:00
Josef Bacik
083e75e7e6 btrfs: export find_delalloc_range
This utilizes internal stuff to the extent_io_tree, so we need to export
it before we move it.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:47 +01:00
Josef Bacik
9c7d3a5483 btrfs: move extent_io_tree defs to their own header
extent_io.c/h are huge, encompassing a bunch of different things.  The
extent_io_tree code can live on its own, so separate this out.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:47 +01:00
Josef Bacik
6f0d04f8e7 btrfs: separate out the extent io init function
We are moving extent_io_tree into it's on file, so separate out the
extent_state init stuff from extent_io_tree_init().

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:47 +01:00
Josef Bacik
33ca832fef btrfs: separate out the extent leak code
We check both extent buffer and extent state leaks in the same function,
separate these two functions out so we can move them around.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:46 +01:00
Qu Wenruo
34ffafdba1 btrfs: ctree: Remove stray comment of setting up path lock
The following comment shows up in btrfs_search_slot() with out much
sense:

	/*
	 * setup the path here so we can release it under lock
	 * contention with the cow code
	 */
	if (cow) {
		/* code touching path->lock[] is far away from here */
	}

This comment hasn't been cleaned up after the relevant code has been
removed.

The original code is introduced in commit 65b51a009e
("btrfs_search_slot: reduce lock contention by cowing in two stages"):

  +
  +               /*
  +                * setup the path here so we can release it under lock
  +                * contention with the cow code
  +                */
  +               p->nodes[level] = b;
  +               if (!p->skip_locking)
  +                       p->locks[level] = 1;
  +

But in current code, we have different timing for modifying path lock,
so just remove the comment.

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>
2019-11-18 12:46:46 +01:00
Qu Wenruo
abe9339d69 btrfs: ctree: Reduce one indent level for btrfs_search_old_slot()
Similar to btrfs_search_slot() done in previous patch, make a shortcut
for the level 0 case and allow to reduce indentation for the remaining
case.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:46 +01:00
Qu Wenruo
f624d97608 btrfs: ctree: Reduce one indent level for btrfs_search_slot()
In btrfs_search_slot(), we something like:

	if (level != 0) {
		/* Do search inside tree nodes*/
	} else {
		/* Do search inside tree leaves */
		goto done;
	}

This caused extra indent for tree node search code.  Change it to
something like:

	if (level == 0) {
		/* Do search inside tree leaves */
		goto done'
	}
	/* Do search inside tree nodes */

So we have more space to maneuver our code, this is especially useful as
the tree nodes search code is more complex than the leaves search code.

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>
2019-11-18 12:46:46 +01:00
Qu Wenruo
71bf92a9b8 btrfs: tree-checker: Add check for INODE_REF
For INODE_REF we will check:
- Objectid (ino) against previous key
  To detect missing INODE_ITEM.

- No overflow/padding in the data payload
  Much like DIR_ITEM, but with less members to check.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:46 +01:00
Qu Wenruo
c18679ebd8 btrfs: tree-checker: Try to detect missing INODE_ITEM
For the following items, key->objectid is inode number:
- DIR_ITEM
- DIR_INDEX
- XATTR_ITEM
- EXTENT_DATA
- INODE_REF

So in the subvolume tree, such items must have its previous item share the
same objectid, e.g.:

 (257 INODE_ITEM 0)
 (257 DIR_INDEX xxx)
 (257 DIR_ITEM xxx)
 (258 INODE_ITEM 0)
 (258 INODE_REF 0)
 (258 XATTR_ITEM 0)
 (258 EXTENT_DATA 0)

But if we have the following sequence, then there is definitely
something wrong, normally some INODE_ITEM is missing, like:

 (257 INODE_ITEM 0)
 (257 DIR_INDEX xxx)
 (257 DIR_ITEM xxx)
 (258 XATTR_ITEM 0)  <<< objecitd suddenly changed to 258
 (258 EXTENT_DATA 0)

So just by checking the previous key for above inode based key types, we
can detect a missing inode item.

For INODE_REF key type, the check will be added along with INODE_REF
checker.

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>
2019-11-18 12:46:46 +01:00
Filipe Manana
b9fae2ebee Btrfs: make btrfs_wait_extents() static
It's not used ouside of transaction.c

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:45 +01:00
Nikolay Borisov
35b814f3c5 btrfs: Add assert to catch nested transaction commit
A recent patch to btrfs showed that there was at least 1 case where a
nested transaction was committed. Nested transaction in this case means
a code which has a transaction handle calls some function which in turn
obtains a copy of the same transaction handle. In such cases the correct
thing to do is for the lower callee to call btrfs_end_transaction which
contains appropriate checks so as to not commit the transaction which
will result in stale trans handler for the caller.

To catch such cases add an assert in btrfs_commit_transaction ensuring
btrfs_trans_handle::use_count is always 1.

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>
2019-11-18 12:46:45 +01:00
Goldwyn Rodrigues
9cf35f6735 btrfs: simplify inode locking for RWF_NOWAIT
This is similar to 942491c9e6 ("xfs: fix AIM7 regression"). Apparently
our current rwsem code doesn't like doing the trylock, then lock for
real scheme. This causes extra contention on the lock and can be
measured eg. by AIM7 benchmark.  So change our read/write methods to
just do the trylock for the RWF_NOWAIT case.

Fixes: edf064e7c6 ("btrfs: nowait aio support")
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18 12:46:45 +01:00
Linus Torvalds
afd7a71872 for-5.4-rc7-tag
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Merge tag 'for-5.4-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fix from David Sterba:
 "A fix for an older bug that has started to show up during testing
  (because of an updated test for rename exchange).

  It's an in-memory corruption caused by local variable leaking out of
  the function scope"

* tag 'for-5.4-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix log context list corruption after rename exchange operation
2019-11-13 12:06:10 -08:00
Filipe Manana
e6c617102c Btrfs: fix log context list corruption after rename exchange operation
During rename exchange we might have successfully log the new name in the
source root's log tree, in which case we leave our log context (allocated
on stack) in the root's list of log contextes. However we might fail to
log the new name in the destination root, in which case we fallback to
a transaction commit later and never sync the log of the source root,
which causes the source root log context to remain in the list of log
contextes. This later causes invalid memory accesses because the context
was allocated on stack and after rename exchange finishes the stack gets
reused and overwritten for other purposes.

The kernel's linked list corruption detector (CONFIG_DEBUG_LIST=y) can
detect this and report something like the following:

  [  691.489929] ------------[ cut here ]------------
  [  691.489947] list_add corruption. prev->next should be next (ffff88819c944530), but was ffff8881c23f7be4. (prev=ffff8881c23f7a38).
  [  691.489967] WARNING: CPU: 2 PID: 28933 at lib/list_debug.c:28 __list_add_valid+0x95/0xe0
  (...)
  [  691.489998] CPU: 2 PID: 28933 Comm: fsstress Not tainted 5.4.0-rc6-btrfs-next-62 #1
  [  691.490001] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
  [  691.490003] RIP: 0010:__list_add_valid+0x95/0xe0
  (...)
  [  691.490007] RSP: 0018:ffff8881f0b3faf8 EFLAGS: 00010282
  [  691.490010] RAX: 0000000000000000 RBX: ffff88819c944530 RCX: 0000000000000000
  [  691.490011] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffffa2c497e0
  [  691.490013] RBP: ffff8881f0b3fe68 R08: ffffed103eaa4115 R09: ffffed103eaa4114
  [  691.490015] R10: ffff88819c944000 R11: ffffed103eaa4115 R12: 7fffffffffffffff
  [  691.490016] R13: ffff8881b4035610 R14: ffff8881e7b84728 R15: 1ffff1103e167f7b
  [  691.490019] FS:  00007f4b25ea2e80(0000) GS:ffff8881f5500000(0000) knlGS:0000000000000000
  [  691.490021] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [  691.490022] CR2: 00007fffbb2d4eec CR3: 00000001f2a4a004 CR4: 00000000003606e0
  [  691.490025] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [  691.490027] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  [  691.490029] Call Trace:
  [  691.490058]  btrfs_log_inode_parent+0x667/0x2730 [btrfs]
  [  691.490083]  ? join_transaction+0x24a/0xce0 [btrfs]
  [  691.490107]  ? btrfs_end_log_trans+0x80/0x80 [btrfs]
  [  691.490111]  ? dget_parent+0xb8/0x460
  [  691.490116]  ? lock_downgrade+0x6b0/0x6b0
  [  691.490121]  ? rwlock_bug.part.0+0x90/0x90
  [  691.490127]  ? do_raw_spin_unlock+0x142/0x220
  [  691.490151]  btrfs_log_dentry_safe+0x65/0x90 [btrfs]
  [  691.490172]  btrfs_sync_file+0x9f1/0xc00 [btrfs]
  [  691.490195]  ? btrfs_file_write_iter+0x1800/0x1800 [btrfs]
  [  691.490198]  ? rcu_read_lock_any_held.part.11+0x20/0x20
  [  691.490204]  ? __do_sys_newstat+0x88/0xd0
  [  691.490207]  ? cp_new_stat+0x5d0/0x5d0
  [  691.490218]  ? do_fsync+0x38/0x60
  [  691.490220]  do_fsync+0x38/0x60
  [  691.490224]  __x64_sys_fdatasync+0x32/0x40
  [  691.490228]  do_syscall_64+0x9f/0x540
  [  691.490233]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
  [  691.490235] RIP: 0033:0x7f4b253ad5f0
  (...)
  [  691.490239] RSP: 002b:00007fffbb2d6078 EFLAGS: 00000246 ORIG_RAX: 000000000000004b
  [  691.490242] RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4b253ad5f0
  [  691.490244] RDX: 00007fffbb2d5fe0 RSI: 00007fffbb2d5fe0 RDI: 0000000000000003
  [  691.490245] RBP: 000000000000000d R08: 0000000000000001 R09: 00007fffbb2d608c
  [  691.490247] R10: 00000000000002e8 R11: 0000000000000246 R12: 00000000000001f4
  [  691.490248] R13: 0000000051eb851f R14: 00007fffbb2d6120 R15: 00005635a498bda0

This started happening recently when running some test cases from fstests
like btrfs/004 for example, because support for rename exchange was added
last week to fsstress from fstests.

So fix this by deleting the log context for the source root from the list
if we have logged the new name in the source root.

Reported-by: Su Yue <Damenly_Su@gmx.com>
Fixes: d4682ba03e ("Btrfs: sync log after logging new name")
CC: stable@vger.kernel.org # 4.19+
Tested-by: Su Yue <Damenly_Su@gmx.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-11 19:46:02 +01:00
Linus Torvalds
00aff68362 for-5.4-rc6-tag
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Merge tag 'for-5.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few regressions and fixes for stable.

  Regressions:

   - fix a race leading to metadata space leak after task received a
     signal

   - un-deprecate 2 ioctls, marked as deprecated by mistake

  Fixes:

   - fix limit check for number of devices during chunk allocation

   - fix a race due to double evaluation of i_size_read inside max()
     macro, can cause a crash

   - remove wrong device id check in tree-checker"

* tag 'for-5.4-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: un-deprecate ioctls START_SYNC and WAIT_SYNC
  btrfs: save i_size to avoid double evaluation of i_size_read in compress_file_range
  Btrfs: fix race leading to metadata space leak after task received signal
  btrfs: tree-checker: Fix wrong check on max devid
  btrfs: Consider system chunk array size for new SYSTEM chunks
2019-11-09 08:51:37 -08:00
David Sterba
a5009d3a31 btrfs: un-deprecate ioctls START_SYNC and WAIT_SYNC
The two ioctls START_SYNC and WAIT_SYNC were mistakenly marked as
deprecated and scheduled for removal but we actualy do use them for
'btrfs subvolume delete -C/-c'. The deprecated thing in ebc87351e5
should have been just the async flag for subvolume creation.

The deprecation has been added in this development cycle, remove it
until it's time.

Fixes: ebc87351e5 ("btrfs: Deprecate BTRFS_SUBVOL_CREATE_ASYNC flag")
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-04 21:42:01 +01:00
Josef Bacik
d98da49977 btrfs: save i_size to avoid double evaluation of i_size_read in compress_file_range
We hit a regression while rolling out 5.2 internally where we were
hitting the following panic

  kernel BUG at mm/page-writeback.c:2659!
  RIP: 0010:clear_page_dirty_for_io+0xe6/0x1f0
  Call Trace:
   __process_pages_contig+0x25a/0x350
   ? extent_clear_unlock_delalloc+0x43/0x70
   submit_compressed_extents+0x359/0x4d0
   normal_work_helper+0x15a/0x330
   process_one_work+0x1f5/0x3f0
   worker_thread+0x2d/0x3d0
   ? rescuer_thread+0x340/0x340
   kthread+0x111/0x130
   ? kthread_create_on_node+0x60/0x60
   ret_from_fork+0x1f/0x30

This is happening because the page is not locked when doing
clear_page_dirty_for_io.  Looking at the core dump it was because our
async_extent had a ram_size of 24576 but our async_chunk range only
spanned 20480, so we had a whole extra page in our ram_size for our
async_extent.

This happened because we try not to compress pages outside of our
i_size, however a cleanup patch changed us to do

actual_end = min_t(u64, i_size_read(inode), end + 1);

which is problematic because i_size_read() can evaluate to different
values in between checking and assigning.  So either an expanding
truncate or a fallocate could increase our i_size while we're doing
writeout and actual_end would end up being past the range we have
locked.

I confirmed this was what was happening by installing a debug kernel
that had

  actual_end = min_t(u64, i_size_read(inode), end + 1);
  if (actual_end > end + 1) {
	  printk(KERN_ERR "KABOOM\n");
	  actual_end = end + 1;
  }

and installing it onto 500 boxes of the tier that had been seeing the
problem regularly.  Last night I got my debug message and no panic,
confirming what I expected.

[ dsterba: the assembly confirms a tiny race window:

    mov    0x20(%rsp),%rax
    cmp    %rax,0x48(%r15)           # read
    movl   $0x0,0x18(%rsp)
    mov    %rax,%r12
    mov    %r14,%rax
    cmovbe 0x48(%r15),%r12           # eval

  Where r15 is inode and 0x48 is offset of i_size.

  The original fix was to revert 62b3762271 that would do an
  intermediate assignment and this would also avoid the doulble
  evaluation but is not future-proof, should the compiler merge the
  stores and call i_size_read anyway.

  There's a patch adding READ_ONCE to i_size_read but that's not being
  applied at the moment and we need to fix the bug. Instead, emulate
  READ_ONCE by two barrier()s that's what effectively happens. The
  assembly confirms single evaluation:

    mov    0x48(%rbp),%rax          # read once
    mov    0x20(%rsp),%rcx
    mov    $0x20,%edx
    cmp    %rax,%rcx
    cmovbe %rcx,%rax
    mov    %rax,(%rsp)
    mov    %rax,%rcx
    mov    %r14,%rax

  Where 0x48(%rbp) is inode->i_size stored to %eax.
]

Fixes: 62b3762271 ("btrfs: Remove isize local variable in compress_file_range")
CC: stable@vger.kernel.org # v5.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ changelog updated ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-04 21:41:49 +01:00
Filipe Manana
0cab7acc4a Btrfs: fix race leading to metadata space leak after task received signal
When a task that is allocating metadata needs to wait for the async
reclaim job to process its ticket and gets a signal (because it was killed
for example) before doing the wait, the task ends up erroring out but
with space reserved for its ticket, which never gets released, resulting
in a metadata space leak (more specifically a leak in the bytes_may_use
counter of the metadata space_info object).

Here's the sequence of steps leading to the space leak:

1) A task tries to create a file for example, so it ends up trying to
   start a transaction at btrfs_create();

2) The filesystem is currently in a state where there is not enough
   metadata free space to satisfy the transaction's needs. So at
   space-info.c:__reserve_metadata_bytes() we create a ticket and
   add it to the list of tickets of the space info object. Also,
   because the metadata async reclaim job is not running, we queue
   a job ro run metadata reclaim;

3) In the meanwhile the task receives a signal (like SIGTERM from
   a kill command for example);

4) After queing the async reclaim job, at __reserve_metadata_bytes(),
   we unlock the metadata space info and call handle_reserve_ticket();

5) That last function calls wait_reserve_ticket(), which acquires the
   lock from the metadata space info. Then in the first iteration of
   its while loop, it calls prepare_to_wait_event(), which returns
   -ERESTARTSYS because the task has a pending signal. As a result,
   we set the error field of the ticket to -EINTR and exit the while
   loop without deleting the ticket from the list of tickets (in the
   space info object). After exiting the loop we unlock the space info;

6) The async reclaim job is able to release enough metadata, acquires
   the metadata space info's lock and then reserves space for the ticket,
   since the ticket is still in the list of (non-priority) tickets. The
   space reservation happens at btrfs_try_granting_tickets(), called from
   maybe_fail_all_tickets(). This increments the bytes_may_use counter
   from the metadata space info object, sets the ticket's bytes field to
   zero (meaning success, that space was reserved) and removes it from
   the list of tickets;

7) wait_reserve_ticket() returns, with the error field of the ticket
   set to -EINTR. Then handle_reserve_ticket() just propagates that error
   to the caller. Because an error was returned, the caller does not
   release the reserved space, since the expectation is that any error
   means no space was reserved.

Fix this by removing the ticket from the list, while holding the space
info lock, at wait_reserve_ticket() when prepare_to_wait_event() returns
an error.

Also add some comments and an assertion to guarantee we never end up with
a ticket that has an error set and a bytes counter field set to zero, to
more easily detect regressions in the future.

This issue could be triggered sporadically by some test cases from fstests
such as generic/269 for example, which tries to fill a filesystem and then
kills fsstress processes running in the background.

When this issue happens, we get a warning in syslog/dmesg when unmounting
the filesystem, like the following:

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 13240 at fs/btrfs/block-group.c:3186 btrfs_free_block_groups+0x314/0x470 [btrfs]
  (...)
  CPU: 0 PID: 13240 Comm: umount Tainted: G        W    L    5.3.0-rc8-btrfs-next-48+ #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
  RIP: 0010:btrfs_free_block_groups+0x314/0x470 [btrfs]
  (...)
  RSP: 0018:ffff9910c14cfdb8 EFLAGS: 00010286
  RAX: 0000000000000024 RBX: ffff89cd8a4d55f0 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffff89cdf6a178a8 RDI: ffff89cdf6a178a8
  RBP: ffff9910c14cfde8 R08: 0000000000000000 R09: 0000000000000001
  R10: ffff89cd4d618040 R11: 0000000000000000 R12: ffff89cd8a4d5508
  R13: ffff89cde7c4a600 R14: dead000000000122 R15: dead000000000100
  FS:  00007f42754432c0(0000) GS:ffff89cdf6a00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007fd25a47f730 CR3: 000000021f8d6006 CR4: 00000000003606f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   close_ctree+0x1ad/0x390 [btrfs]
   generic_shutdown_super+0x6c/0x110
   kill_anon_super+0xe/0x30
   btrfs_kill_super+0x12/0xa0 [btrfs]
   deactivate_locked_super+0x3a/0x70
   cleanup_mnt+0xb4/0x160
   task_work_run+0x7e/0xc0
   exit_to_usermode_loop+0xfa/0x100
   do_syscall_64+0x1cb/0x220
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x7f4274d2cb37
  (...)
  RSP: 002b:00007ffcff701d38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
  RAX: 0000000000000000 RBX: 0000557ebde2f060 RCX: 00007f4274d2cb37
  RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000557ebde2f240
  RBP: 0000557ebde2f240 R08: 0000557ebde2f270 R09: 0000000000000015
  R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f427522ee64
  R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffcff701fc0
  irq event stamp: 0
  hardirqs last  enabled at (0): [<0000000000000000>] 0x0
  hardirqs last disabled at (0): [<ffffffffb12b561e>] copy_process+0x75e/0x1fd0
  softirqs last  enabled at (0): [<ffffffffb12b561e>] copy_process+0x75e/0x1fd0
  softirqs last disabled at (0): [<0000000000000000>] 0x0
  ---[ end trace bcf4b235461b26f6 ]---
  BTRFS info (device sdb): space_info 4 has 19116032 free, is full
  BTRFS info (device sdb): space_info total=33554432, used=14176256, pinned=0, reserved=0, may_use=196608, readonly=65536
  BTRFS info (device sdb): global_block_rsv: size 0 reserved 0
  BTRFS info (device sdb): trans_block_rsv: size 0 reserved 0
  BTRFS info (device sdb): chunk_block_rsv: size 0 reserved 0
  BTRFS info (device sdb): delayed_block_rsv: size 0 reserved 0
  BTRFS info (device sdb): delayed_refs_rsv: size 0 reserved 0

Fixes: 374bf9c5cd ("btrfs: unify error handling for ticket flushing")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-25 19:11:34 +02:00
Qu Wenruo
8bb177d18f btrfs: tree-checker: Fix wrong check on max devid
[BUG]
The following script will cause false alert on devid check.
  #!/bin/bash

  dev1=/dev/test/test
  dev2=/dev/test/scratch1
  mnt=/mnt/btrfs

  umount $dev1 &> /dev/null
  umount $dev2 &> /dev/null
  umount $mnt &> /dev/null

  mkfs.btrfs -f $dev1

  mount $dev1 $mnt

  _fail()
  {
          echo "!!! FAILED !!!"
          exit 1
  }

  for ((i = 0; i < 4096; i++)); do
          btrfs dev add -f $dev2 $mnt || _fail
          btrfs dev del $dev1 $mnt || _fail
          dev_tmp=$dev1
          dev1=$dev2
          dev2=$dev_tmp
  done

[CAUSE]
Tree-checker uses BTRFS_MAX_DEVS() and BTRFS_MAX_DEVS_SYS_CHUNK() as
upper limit for devid.  But we can have devid holes just like above
script.

So the check for devid is incorrect and could cause false alert.

[FIX]
Just remove the whole devid check.  We don't have any hard requirement
for devid assignment.

Furthermore, even devid could get corrupted by a bitflip, we still have
dev extents verification at mount time, so corrupted data won't sneak
in.

This fixes fstests btrfs/194.

Reported-by: Anand Jain <anand.jain@oracle.com>
Fixes: ab4ba2e133 ("btrfs: tree-checker: Verify dev item")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-25 19:11:34 +02:00
Qu Wenruo
c17add7a1c btrfs: Consider system chunk array size for new SYSTEM chunks
For SYSTEM chunks, despite the regular chunk item size limit, there is
another limit due to system chunk array size.

The extra limit was removed in a refactoring, so add it back.

Fixes: e3ecdb3fde ("btrfs: factor out devs_max setting in __btrfs_alloc_chunk")
CC: stable@vger.kernel.org # 5.3+
Reviewed-by: Nikolay Borisov <nborisov@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>
2019-10-25 19:11:34 +02:00
Linus Torvalds
54955e3bfd for-5.4-rc4-tag
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Merge tag 'for-5.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:

 - fixes of error handling cleanup of metadata accounting with qgroups
   enabled

 - fix swapped values for qgroup tracepoints

 - fix race when handling full sync flag

 - don't start unused worker thread, functionality removed already

* tag 'for-5.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: check for the full sync flag while holding the inode lock during fsync
  Btrfs: fix qgroup double free after failure to reserve metadata for delalloc
  btrfs: tracepoints: Fix bad entry members of qgroup events
  btrfs: tracepoints: Fix wrong parameter order for qgroup events
  btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents()
  btrfs: don't needlessly create extent-refs kernel thread
  btrfs: block-group: Fix a memory leak due to missing btrfs_put_block_group()
  Btrfs: add missing extents release on file extent cluster relocation error
2019-10-23 06:14:29 -04:00
Filipe Manana
ba0b084ac3 Btrfs: check for the full sync flag while holding the inode lock during fsync
We were checking for the full fsync flag in the inode before locking the
inode, which is racy, since at that that time it might not be set but
after we acquire the inode lock some other task set it. One case where
this can happen is on a system low on memory and some concurrent task
failed to allocate an extent map and therefore set the full sync flag on
the inode, to force the next fsync to work in full mode.

A consequence of missing the full fsync flag set is hitting the problems
fixed by commit 0c713cbab6 ("Btrfs: fix race between ranged fsync and
writeback of adjacent ranges"), BUG_ON() when dropping extents from a log
tree, hitting assertion failures at tree-log.c:copy_items() or all sorts
of weird inconsistencies after replaying a log due to file extents items
representing ranges that overlap.

So just move the check such that it's done after locking the inode and
before starting writeback again.

Fixes: 0c713cbab6 ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-17 20:36:02 +02:00
Filipe Manana
c7967fc149 Btrfs: fix qgroup double free after failure to reserve metadata for delalloc
If we fail to reserve metadata for delalloc operations we end up releasing
the previously reserved qgroup amount twice, once explicitly under the
'out_qgroup' label by calling btrfs_qgroup_free_meta_prealloc() and once
again, under label 'out_fail', by calling btrfs_inode_rsv_release() with a
value of 'true' for its 'qgroup_free' argument, which results in
btrfs_qgroup_free_meta_prealloc() being called again, so we end up having
a double free.

Also if we fail to reserve the necessary qgroup amount, we jump to the
label 'out_fail', which calls btrfs_inode_rsv_release() and that in turns
calls btrfs_qgroup_free_meta_prealloc(), even though we weren't able to
reserve any qgroup amount. So we freed some amount we never reserved.

So fix this by removing the call to btrfs_inode_rsv_release() in the
failure path, since it's not necessary at all as we haven't changed the
inode's block reserve in any way at this point.

Fixes: c8eaeac7b7 ("btrfs: reserve delalloc metadata differently")
CC: stable@vger.kernel.org # 5.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-17 20:13:44 +02:00
Qu Wenruo
fd2b007eae btrfs: tracepoints: Fix wrong parameter order for qgroup events
[BUG]
For btrfs:qgroup_meta_reserve event, the trace event can output garbage:

  qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2

The diff should always be alinged to sector size (4k), so there is
definitely something wrong.

[CAUSE]
For the wrong @diff, it's caused by wrong parameter order.
The correct parameters are:

  struct btrfs_root, s64 diff, int type.

However the parameters used are:

  struct btrfs_root, int type, s64 diff.

Fixes: 4ee0d8832c ("btrfs: qgroup: Update trace events for metadata reservation")
CC: stable@vger.kernel.org # 4.19+
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>
2019-10-17 14:09:31 +02:00
Qu Wenruo
8702ba9396 btrfs: qgroup: Always free PREALLOC META reserve in btrfs_delalloc_release_extents()
[Background]
Btrfs qgroup uses two types of reserved space for METADATA space,
PERTRANS and PREALLOC.

PERTRANS is metadata space reserved for each transaction started by
btrfs_start_transaction().
While PREALLOC is for delalloc, where we reserve space before joining a
transaction, and finally it will be converted to PERTRANS after the
writeback is done.

[Inconsistency]
However there is inconsistency in how we handle PREALLOC metadata space.

The most obvious one is:
In btrfs_buffered_write():
	btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true);

We always free qgroup PREALLOC meta space.

While in btrfs_truncate_block():
	btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0));

We only free qgroup PREALLOC meta space when something went wrong.

[The Correct Behavior]
The correct behavior should be the one in btrfs_buffered_write(), we
should always free PREALLOC metadata space.

The reason is, the btrfs_delalloc_* mechanism works by:
- Reserve metadata first, even it's not necessary
  In btrfs_delalloc_reserve_metadata()

- Free the unused metadata space
  Normally in:
  btrfs_delalloc_release_extents()
  |- btrfs_inode_rsv_release()
     Here we do calculation on whether we should release or not.

E.g. for 64K buffered write, the metadata rsv works like:

/* The first page */
reserve_meta:	num_bytes=calc_inode_reservations()
free_meta:	num_bytes=0
total:		num_bytes=calc_inode_reservations()
/* The first page caused one outstanding extent, thus needs metadata
   rsv */

/* The 2nd page */
reserve_meta:	num_bytes=calc_inode_reservations()
free_meta:	num_bytes=calc_inode_reservations()
total:		not changed
/* The 2nd page doesn't cause new outstanding extent, needs no new meta
   rsv, so we free what we have reserved */

/* The 3rd~16th pages */
reserve_meta:	num_bytes=calc_inode_reservations()
free_meta:	num_bytes=calc_inode_reservations()
total:		not changed (still space for one outstanding extent)

This means, if btrfs_delalloc_release_extents() determines to free some
space, then those space should be freed NOW.
So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other
than btrfs_qgroup_convert_reserved_meta().

The good news is:
- The callers are not that hot
  The hottest caller is in btrfs_buffered_write(), which is already
  fixed by commit 336a8bb8e3 ("btrfs: Fix wrong
  btrfs_delalloc_release_extents parameter"). Thus it's not that
  easy to cause false EDQUOT.

- The trans commit in advance for qgroup would hide the bug
  Since commit f5fef45936 ("btrfs: qgroup: Make qgroup async transaction
  commit more aggressive"), when btrfs qgroup metadata free space is slow,
  it will try to commit transaction and free the wrongly converted
  PERTRANS space, so it's not that easy to hit such bug.

[FIX]
So to fix the problem, remove the @qgroup_free parameter for
btrfs_delalloc_release_extents(), and always pass true to
btrfs_inode_rsv_release().

Reported-by: Filipe Manana <fdmanana@suse.com>
Fixes: 43b18595d6 ("btrfs: qgroup: Use separate meta reservation type for delalloc")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-15 18:50:07 +02:00
David Sterba
80ed4548d0 btrfs: don't needlessly create extent-refs kernel thread
The patch 32b593bfcb ("Btrfs: remove no longer used function to run
delayed refs asynchronously") removed the async delayed refs but the
thread has been created, without any use. Remove it to avoid resource
consumption.

Fixes: 32b593bfcb ("Btrfs: remove no longer used function to run delayed refs asynchronously")
CC: stable@vger.kernel.org # 5.2+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-15 15:43:29 +02:00
Qu Wenruo
4b654acdae btrfs: block-group: Fix a memory leak due to missing btrfs_put_block_group()
In btrfs_read_block_groups(), if we have an invalid block group which
has mixed type (DATA|METADATA) while the fs doesn't have MIXED_GROUPS
feature, we error out without freeing the block group cache.

This patch will add the missing btrfs_put_block_group() to prevent
memory leak.

Note for stable backports: the file to patch in versions <= 5.3 is
fs/btrfs/extent-tree.c

Fixes: 49303381f1 ("Btrfs: bail out if block group has different mixed flag")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-11 21:27:51 +02:00
Filipe Manana
44db1216ef Btrfs: add missing extents release on file extent cluster relocation error
If we error out when finding a page at relocate_file_extent_cluster(), we
need to release the outstanding extents counter on the relocation inode,
set by the previous call to btrfs_delalloc_reserve_metadata(), otherwise
the inode's block reserve size can never decrease to zero and metadata
space is leaked. Therefore add a call to btrfs_delalloc_release_extents()
in case we can't find the target page.

Fixes: 8b62f87bad ("Btrfs: rework outstanding_extents")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-11 19:49:11 +02:00
Linus Torvalds
f8779876d4 for-5.4-rc2-tag
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Merge tag 'for-5.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

Pull btrfs fixes from David Sterba:
 "A few more stabitly fixes, one build warning fix.

   - fix inode allocation under NOFS context

   - fix leak in fiemap due to concurrent append writes

   - fix log-root tree updates

   - fix balance convert of single profile on 32bit architectures

   - silence false positive warning on old GCCs (code moved in rc1)"

* tag 'for-5.4-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: silence maybe-uninitialized warning in clone_range
  btrfs: fix uninitialized ret in ref-verify
  btrfs: allocate new inode in NOFS context
  btrfs: fix balance convert to single on 32-bit host CPUs
  btrfs: fix incorrect updating of log root tree
  Btrfs: fix memory leak due to concurrent append writes with fiemap
2019-10-10 08:30:51 -07:00
Austin Kim
431d39887d btrfs: silence maybe-uninitialized warning in clone_range
GCC throws warning message as below:

‘clone_src_i_size’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
 #define IS_ALIGNED(x, a)  (((x) & ((typeof(x))(a) - 1)) == 0)
                       ^
fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here
 u64 clone_src_i_size;
   ^
The clone_src_i_size is only used as call-by-reference
in a call to get_inode_info().

Silence the warning by initializing clone_src_i_size to 0.

Note that the warning is a false positive and reported by older versions
of GCC (eg. 7.x) but not eg 9.x. As there have been numerous people, the
patch is applied. Setting clone_src_i_size to 0 does not otherwise make
sense and would not do any action in case the code changes in the future.

Signed-off-by: Austin Kim <austindh.kim@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add note ]
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-08 13:14:55 +02:00
Josef Bacik
c5f4987e86 btrfs: fix uninitialized ret in ref-verify
Coverity caught a case where we could return with a uninitialized value
in ret in process_leaf.  This is actually pretty likely because we could
very easily run into a block group item key and have a garbage value in
ret and think there was an errror.  Fix this by initializing ret to 0.

Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: fd708b81d9 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-03 15:00:56 +02:00
Josef Bacik
11a19a9087 btrfs: allocate new inode in NOFS context
A user reported a lockdep splat

 ======================================================
 WARNING: possible circular locking dependency detected
 5.2.11-gentoo #2 Not tainted
 ------------------------------------------------------
 kswapd0/711 is trying to acquire lock:
 000000007777a663 (sb_internal){.+.+}, at: start_transaction+0x3a8/0x500

but task is already holding lock:
 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (fs_reclaim){+.+.}:
 kmem_cache_alloc+0x1f/0x1c0
 btrfs_alloc_inode+0x1f/0x260
 alloc_inode+0x16/0xa0
 new_inode+0xe/0xb0
 btrfs_new_inode+0x70/0x610
 btrfs_symlink+0xd0/0x420
 vfs_symlink+0x9c/0x100
 do_symlinkat+0x66/0xe0
 do_syscall_64+0x55/0x1c0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (sb_internal){.+.+}:
 __sb_start_write+0xf6/0x150
 start_transaction+0x3a8/0x500
 btrfs_commit_inode_delayed_inode+0x59/0x110
 btrfs_evict_inode+0x19e/0x4c0
 evict+0xbc/0x1f0
 inode_lru_isolate+0x113/0x190
 __list_lru_walk_one.isra.4+0x5c/0x100
 list_lru_walk_one+0x32/0x50
 prune_icache_sb+0x36/0x80
 super_cache_scan+0x14a/0x1d0
 do_shrink_slab+0x131/0x320
 shrink_node+0xf7/0x380
 balance_pgdat+0x2d5/0x640
 kswapd+0x2ba/0x5e0
 kthread+0x147/0x160
 ret_from_fork+0x24/0x30

other info that might help us debug this:

 Possible unsafe locking scenario:

 CPU0 CPU1
 ---- ----
 lock(fs_reclaim);
 lock(sb_internal);
 lock(fs_reclaim);
 lock(sb_internal);
*** DEADLOCK ***

 3 locks held by kswapd0/711:
 #0: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30
 #1: 000000004a5100f8 (shrinker_rwsem){++++}, at: shrink_node+0x9a/0x380
 #2: 00000000f956fa46 (&type->s_umount_key#30){++++}, at: super_cache_scan+0x35/0x1d0

stack backtrace:
 CPU: 7 PID: 711 Comm: kswapd0 Not tainted 5.2.11-gentoo #2
 Hardware name: Dell Inc. Precision Tower 3620/0MWYPT, BIOS 2.4.2 09/29/2017
 Call Trace:
 dump_stack+0x85/0xc7
 print_circular_bug.cold.40+0x1d9/0x235
 __lock_acquire+0x18b1/0x1f00
 lock_acquire+0xa6/0x170
 ? start_transaction+0x3a8/0x500
 __sb_start_write+0xf6/0x150
 ? start_transaction+0x3a8/0x500
 start_transaction+0x3a8/0x500
 btrfs_commit_inode_delayed_inode+0x59/0x110
 btrfs_evict_inode+0x19e/0x4c0
 ? var_wake_function+0x20/0x20
 evict+0xbc/0x1f0
 inode_lru_isolate+0x113/0x190
 ? discard_new_inode+0xc0/0xc0
 __list_lru_walk_one.isra.4+0x5c/0x100
 ? discard_new_inode+0xc0/0xc0
 list_lru_walk_one+0x32/0x50
 prune_icache_sb+0x36/0x80
 super_cache_scan+0x14a/0x1d0
 do_shrink_slab+0x131/0x320
 shrink_node+0xf7/0x380
 balance_pgdat+0x2d5/0x640
 kswapd+0x2ba/0x5e0
 ? __wake_up_common_lock+0x90/0x90
 kthread+0x147/0x160
 ? balance_pgdat+0x640/0x640
 ? __kthread_create_on_node+0x160/0x160
 ret_from_fork+0x24/0x30

This is because btrfs_new_inode() calls new_inode() under the
transaction.  We could probably move the new_inode() outside of this but
for now just wrap it in memalloc_nofs_save().

Reported-by: Zdenek Sojka <zsojka@seznam.cz>
Fixes: 712e36c5f2 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode")
CC: stable@vger.kernel.org # 4.16+
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>
2019-10-01 20:12:27 +02:00
Zygo Blaxell
7a54789074 btrfs: fix balance convert to single on 32-bit host CPUs
Currently, the command:

	btrfs balance start -dconvert=single,soft .

on a Raspberry Pi produces the following kernel message:

	BTRFS error (device mmcblk0p2): balance: invalid convert data profile single

This fails because we use is_power_of_2(unsigned long) to validate
the new data profile, the constant for 'single' profile uses bit 48,
and there are only 32 bits in a long on ARM.

Fix by open-coding the check using u64 variables.

Tested by completing the original balance command on several Raspberry
Pis.

Fixes: 818255feec ("btrfs: use common helper instead of open coding a bit test")
CC: stable@vger.kernel.org # 4.20+
Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2019-10-01 19:37:29 +02:00