In the core function of relocation, build_backref_tree, it needs to
iterate all backref items of one tree block.
Use btrfs_backref_iter infrastructure to do the loop and make the code
more readable.
The backref items look would be much more easier to read:
ret = btrfs_backref_iter_start(iter, cur->bytenr);
for (; ret == 0; ret = btrfs_backref_iter_next(iter)) {
/* The really important work */
}
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
This function will go to the next inline/keyed backref for
btrfs_backref_iter infrastructure.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
Due to the complex nature of btrfs extent tree, when we want to iterate
all backrefs of one extent, this involves quite a lot of work, like
searching the EXTENT_ITEM/METADATA_ITEM, iteration through inline and keyed
backrefs.
Normally this would result in a complex code, something like:
btrfs_search_slot()
/* Ensure we are at EXTENT_ITEM/METADATA_ITEM */
while (1) { /* Loop for extent tree items */
while (ptr < end) { /* Loop for inlined items */
/* Real work here */
}
next:
ret = btrfs_next_item()
/* Ensure we're still at keyed item for specified bytenr */
}
The idea of btrfs_backref_iter is to avoid such complex and hard to
read code structure, but something like the following:
iter = btrfs_backref_iter_alloc();
ret = btrfs_backref_iter_start(iter, bytenr);
if (ret < 0)
goto out;
for (; ; ret = btrfs_backref_iter_next(iter)) {
/* Real work here */
}
out:
btrfs_backref_iter_free(iter);
This patch is just the skeleton + btrfs_backref_iter_start() code.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
Sparse reports a warning at btrfs_tree_lock()
warning: context imbalance in btrfs_tree_lock() - wrong count at exit
The root cause is the missing annotation at btrfs_tree_lock()
Add the missing __acquires(&eb->lock) annotation
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Sparse reports a warning at btrfs_lock_cluster()
warning: context imbalance in btrfs_lock_cluster()
- wrong count
The root cause is the missing annotation at btrfs_lock_cluster()
Add the missing __acquires(&cluster->refill_lock) annotation.
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Some older compilers like gcc-4.8 warn about mismatched curly braces in
a initializer:
fs/btrfs/backref.c: In function 'is_shared_data_backref':
fs/btrfs/backref.c:394:9: error: missing braces around
initializer [-Werror=missing-braces]
struct prelim_ref target = {0};
^
fs/btrfs/backref.c:394:9: error: (near initialization for
'target.rbnode') [-Werror=missing-braces]
Use the GNU empty initializer extension to avoid this.
Fixes: ed58f2e66e ("btrfs: backref, don't add refs from shared block when resolving normal backref")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
One run of btrfs/063 triggered the following lockdep warning:
============================================
WARNING: possible recursive locking detected
5.6.0-rc7-custom+ #48 Not tainted
--------------------------------------------
kworker/u24:0/7 is trying to acquire lock:
ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs]
but task is already holding lock:
ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs]
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(sb_internal#2);
lock(sb_internal#2);
*** DEADLOCK ***
May be due to missing lock nesting notation
4 locks held by kworker/u24:0/7:
#0: ffff88817b495948 ((wq_completion)btrfs-endio-write){+.+.}, at: process_one_work+0x557/0xb80
#1: ffff888189ea7db8 ((work_completion)(&work->normal_work)){+.+.}, at: process_one_work+0x557/0xb80
#2: ffff88817d3a46e0 (sb_internal#2){.+.+}, at: start_transaction+0x66c/0x890 [btrfs]
#3: ffff888174ca4da8 (&fs_info->reloc_mutex){+.+.}, at: btrfs_record_root_in_trans+0x83/0xd0 [btrfs]
stack backtrace:
CPU: 0 PID: 7 Comm: kworker/u24:0 Not tainted 5.6.0-rc7-custom+ #48
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
Call Trace:
dump_stack+0xc2/0x11a
__lock_acquire.cold+0xce/0x214
lock_acquire+0xe6/0x210
__sb_start_write+0x14e/0x290
start_transaction+0x66c/0x890 [btrfs]
btrfs_join_transaction+0x1d/0x20 [btrfs]
find_free_extent+0x1504/0x1a50 [btrfs]
btrfs_reserve_extent+0xd5/0x1f0 [btrfs]
btrfs_alloc_tree_block+0x1ac/0x570 [btrfs]
btrfs_copy_root+0x213/0x580 [btrfs]
create_reloc_root+0x3bd/0x470 [btrfs]
btrfs_init_reloc_root+0x2d2/0x310 [btrfs]
record_root_in_trans+0x191/0x1d0 [btrfs]
btrfs_record_root_in_trans+0x90/0xd0 [btrfs]
start_transaction+0x16e/0x890 [btrfs]
btrfs_join_transaction+0x1d/0x20 [btrfs]
btrfs_finish_ordered_io+0x55d/0xcd0 [btrfs]
finish_ordered_fn+0x15/0x20 [btrfs]
btrfs_work_helper+0x116/0x9a0 [btrfs]
process_one_work+0x632/0xb80
worker_thread+0x80/0x690
kthread+0x1a3/0x1f0
ret_from_fork+0x27/0x50
It's pretty hard to reproduce, only one hit so far.
[CAUSE]
This is because we're calling btrfs_join_transaction() without re-using
the current running one:
btrfs_finish_ordered_io()
|- btrfs_join_transaction() <<< Call #1
|- btrfs_record_root_in_trans()
|- btrfs_reserve_extent()
|- btrfs_join_transaction() <<< Call #2
Normally such btrfs_join_transaction() call should re-use the existing
one, without trying to re-start a transaction.
But the problem is, in btrfs_join_transaction() call #1, we call
btrfs_record_root_in_trans() before initializing current::journal_info.
And in btrfs_join_transaction() call #2, we're relying on
current::journal_info to avoid such deadlock.
[FIX]
Call btrfs_record_root_in_trans() after we have initialized
current::journal_info.
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>
When we have an inode with a prealloc extent that starts at an offset
lower than the i_size and there is another prealloc extent that starts at
an offset beyond i_size, we can end up losing part of the first prealloc
extent (the part that starts at i_size) and have an implicit hole if we
fsync the file and then have a power failure.
Consider the following example with comments explaining how and why it
happens.
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
# Create our test file with 2 consecutive prealloc extents, each with a
# size of 128Kb, and covering the range from 0 to 256Kb, with a file
# size of 0.
$ xfs_io -f -c "falloc -k 0 128K" /mnt/foo
$ xfs_io -c "falloc -k 128K 128K" /mnt/foo
# Fsync the file to record both extents in the log tree.
$ xfs_io -c "fsync" /mnt/foo
# Now do a redudant extent allocation for the range from 0 to 64Kb.
# This will merely increase the file size from 0 to 64Kb. Instead we
# could also do a truncate to set the file size to 64Kb.
$ xfs_io -c "falloc 0 64K" /mnt/foo
# Fsync the file, so we update the inode item in the log tree with the
# new file size (64Kb). This also ends up setting the number of bytes
# for the first prealloc extent to 64Kb. This is done by the truncation
# at btrfs_log_prealloc_extents().
# This means that if a power failure happens after this, a write into
# the file range 64Kb to 128Kb will not use the prealloc extent and
# will result in allocation of a new extent.
$ xfs_io -c "fsync" /mnt/foo
# Now set the file size to 256K with a truncate and then fsync the file.
# Since no changes happened to the extents, the fsync only updates the
# i_size in the inode item at the log tree. This results in an implicit
# hole for the file range from 64Kb to 128Kb, something which fsck will
# complain when not using the NO_HOLES feature if we replay the log
# after a power failure.
$ xfs_io -c "truncate 256K" -c "fsync" /mnt/foo
So instead of always truncating the log to the inode's current i_size at
btrfs_log_prealloc_extents(), check first if there's a prealloc extent
that starts at an offset lower than the i_size and with a length that
crosses the i_size - if there is one, just make sure we truncate to a
size that corresponds to the end offset of that prealloc extent, so
that we don't lose the part of that extent that starts at i_size if a
power failure happens.
A test case for fstests follows soon.
Fixes: 31d11b83b9 ("Btrfs: fix duplicate extents after fsync of file with prealloc extents")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_recover_relocation() invokes btrfs_join_transaction(), which joins
a btrfs_trans_handle object into transactions and returns a reference of
it with increased refcount to "trans".
When btrfs_recover_relocation() returns, "trans" becomes invalid, so the
refcount should be decreased to keep refcount balanced.
The reference counting issue happens in one exception handling path of
btrfs_recover_relocation(). When read_fs_root() failed, the refcnt
increased by btrfs_join_transaction() is not decreased, causing a refcnt
leak.
Fix this issue by calling btrfs_end_transaction() on this error path
when read_fs_root() failed.
Fixes: 79787eaab4 ("btrfs: replace many BUG_ONs with proper error handling")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_remove_block_group() invokes btrfs_lookup_block_group(), which
returns a local reference of the block group that contains the given
bytenr to "block_group" with increased refcount.
When btrfs_remove_block_group() returns, "block_group" becomes invalid,
so the refcount should be decreased to keep refcount balanced.
The reference counting issue happens in several exception handling paths
of btrfs_remove_block_group(). When those error scenarios occur such as
btrfs_alloc_path() returns NULL, the function forgets to decrease its
refcnt increased by btrfs_lookup_block_group() and will cause a refcnt
leak.
Fix this issue by jumping to "out_put_group" label and calling
btrfs_put_block_group() when those error scenarios occur.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Dave reported a problem where we were panicing with generic/475 with
misc-5.7. This is because we were doing IO after we had stopped all of
the worker threads, because we do the log tree cleanup on roots at drop
time. Cleaning up the log tree will always need to do reads if we
happened to have evicted the blocks from memory.
Because of this simply add a helper to btrfs_cleanup_transaction() that
will go through and drop all of the log roots. This gets run before we
do the close_ctree() work, and thus we are allowed to do any reads that
we would need. I ran this through many iterations of generic/475 with
constrained memory and I did not see the issue.
general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
CPU: 2 PID: 12359 Comm: umount Tainted: G W 5.6.0-rc7-btrfs-next-58 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btrfs_queue_work+0x33/0x1c0 [btrfs]
RSP: 0018:ffff9cfb015937d8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8eb5e339ed80 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffff8eb5eb33b770 RDI: ffff8eb5e37a0460
RBP: ffff8eb5eb33b770 R08: 000000000000020c R09: ffffffff9fc09ac0
R10: 0000000000000007 R11: 0000000000000000 R12: 6b6b6b6b6b6b6b6b
R13: ffff9cfb00229040 R14: 0000000000000008 R15: ffff8eb5d3868000
FS: 00007f167ea022c0(0000) GS:ffff8eb5fae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f167e5e0cb1 CR3: 0000000138c18004 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
btrfs_end_bio+0x81/0x130 [btrfs]
__split_and_process_bio+0xaf/0x4e0 [dm_mod]
? percpu_counter_add_batch+0xa3/0x120
dm_process_bio+0x98/0x290 [dm_mod]
? generic_make_request+0xfb/0x410
dm_make_request+0x4d/0x120 [dm_mod]
? generic_make_request+0xfb/0x410
generic_make_request+0x12a/0x410
? submit_bio+0x38/0x160
submit_bio+0x38/0x160
? percpu_counter_add_batch+0xa3/0x120
btrfs_map_bio+0x289/0x570 [btrfs]
? kmem_cache_alloc+0x24d/0x300
btree_submit_bio_hook+0x79/0xc0 [btrfs]
submit_one_bio+0x31/0x50 [btrfs]
read_extent_buffer_pages+0x2fe/0x450 [btrfs]
btree_read_extent_buffer_pages+0x7e/0x170 [btrfs]
walk_down_log_tree+0x343/0x690 [btrfs]
? walk_log_tree+0x3d/0x380 [btrfs]
walk_log_tree+0xf7/0x380 [btrfs]
? plist_requeue+0xf0/0xf0
? delete_node+0x4b/0x230
free_log_tree+0x4c/0x130 [btrfs]
? wait_log_commit+0x140/0x140 [btrfs]
btrfs_free_log+0x17/0x30 [btrfs]
btrfs_drop_and_free_fs_root+0xb0/0xd0 [btrfs]
btrfs_free_fs_roots+0x10c/0x190 [btrfs]
? do_raw_spin_unlock+0x49/0xc0
? _raw_spin_unlock+0x29/0x40
? release_extent_buffer+0x121/0x170 [btrfs]
close_ctree+0x289/0x2e6 [btrfs]
generic_shutdown_super+0x6c/0x110
kill_anon_super+0xe/0x30
btrfs_kill_super+0x12/0x20 [btrfs]
deactivate_locked_super+0x3a/0x70
Reported-by: David Sterba <dsterba@suse.com>
Fixes: 8c38938c7b ("btrfs: move the root freeing stuff into btrfs_put_root")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When cleaning pinned extents right before deleting an unused block group,
we check if there's still a previous transaction running and if so we
increment its reference count before using it for cleaning pinned ranges
in its pinned extents iotree. However we ended up never decrementing the
reference count after using the transaction, resulting in a memory leak.
Fix it by decrementing the reference count.
Fixes: fe119a6eeb ("btrfs: switch to per-transaction pinned extents")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch corrects the SPDX License Identifier style in header file
related to Btrfs File System support. For C header files
Documentation/process/license-rules.rst mandates C-like comments
(opposed to C source files where C++ style should be used).
Changes made by using a script provided by Joe Perches here:
https://lkml.org/lkml/2019/2/7/46.
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I made a mistake with my previous fix, I assumed that we didn't need to
mess with the reloc roots once we were out of the part of relocation where
we are actually moving the extents.
The subtle thing that I missed is that btrfs_init_reloc_root() also
updates the last_trans for the reloc root when we do
btrfs_record_root_in_trans() for the corresponding fs_root. I've added a
comment to make sure future me doesn't make this mistake again.
This showed up as a WARN_ON() in btrfs_copy_root() because our
last_trans didn't == the current transid. This could happen if we
snapshotted a fs root with a reloc root after we set
rc->create_reloc_tree = 0, but before we actually merge the reloc root.
Worth mentioning that the regression produced the following warning
when running snapshot creation and balance in parallel:
BTRFS info (device sdc): relocating block group 30408704 flags metadata|dup
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12823 at fs/btrfs/ctree.c:191 btrfs_copy_root+0x26f/0x430 [btrfs]
CPU: 0 PID: 12823 Comm: btrfs Tainted: G W 5.6.0-rc7-btrfs-next-58 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
RIP: 0010:btrfs_copy_root+0x26f/0x430 [btrfs]
RSP: 0018:ffffb96e044279b8 EFLAGS: 00010202
RAX: 0000000000000009 RBX: ffff9da70bf61000 RCX: ffffb96e04427a48
RDX: ffff9da733a770c8 RSI: ffff9da70bf61000 RDI: ffff9da694163818
RBP: ffff9da733a770c8 R08: fffffffffffffff8 R09: 0000000000000002
R10: ffffb96e044279a0 R11: 0000000000000000 R12: ffff9da694163818
R13: fffffffffffffff8 R14: ffff9da6d2512000 R15: ffff9da714cdac00
FS: 00007fdeacf328c0(0000) GS:ffff9da735e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a2a5b8a118 CR3: 00000001eed78002 CR4: 00000000003606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
? create_reloc_root+0x49/0x2b0 [btrfs]
? kmem_cache_alloc_trace+0xe5/0x200
create_reloc_root+0x8b/0x2b0 [btrfs]
btrfs_reloc_post_snapshot+0x96/0x5b0 [btrfs]
create_pending_snapshot+0x610/0x1010 [btrfs]
create_pending_snapshots+0xa8/0xd0 [btrfs]
btrfs_commit_transaction+0x4c7/0xc50 [btrfs]
? btrfs_mksubvol+0x3cd/0x560 [btrfs]
btrfs_mksubvol+0x455/0x560 [btrfs]
__btrfs_ioctl_snap_create+0x15f/0x190 [btrfs]
btrfs_ioctl_snap_create_v2+0xa4/0xf0 [btrfs]
? mem_cgroup_commit_charge+0x6e/0x540
btrfs_ioctl+0x12d8/0x3760 [btrfs]
? do_raw_spin_unlock+0x49/0xc0
? _raw_spin_unlock+0x29/0x40
? __handle_mm_fault+0x11b3/0x14b0
? ksys_ioctl+0x92/0xb0
ksys_ioctl+0x92/0xb0
? trace_hardirqs_off_thunk+0x1a/0x1c
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x5c/0x280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fdeabd3bdd7
Fixes: 2abc726ab4 ("btrfs: do not init a reloc root if we aren't relocating")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Whenever we add a ticket to a space_info object we increment the object's
reclaim_size counter witht the ticket's bytes, and we decrement it with
the corresponding amount only when we are able to grant the requested
space to the ticket. When we are not able to grant the space to a ticket,
or when the ticket is removed due to a signal (e.g. an application has
received sigterm from the terminal) we never decrement the counter with
the corresponding bytes from the ticket. This leak can result in the
space reclaim code to later do much more work than necessary. So fix it
by decrementing the counter when those two cases happen as well.
Fixes: db161806dc ("btrfs: account ticket size at add/delete time")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is a revert of commit 0a8068a3dd ("btrfs: make ranged full
fsyncs more efficient"), with updated comment in btrfs_sync_file.
Commit 0a8068a3dd ("btrfs: make ranged full fsyncs more efficient")
made full fsyncs operate on the given range only as it assumed it was safe
when using the NO_HOLES feature, since the hole detection was simplified
some time ago and no longer was a source for races with ordered extent
completion of adjacent file ranges.
However it's still not safe to have a full fsync only operate on the given
range, because extent maps for new extents might not be present in memory
due to inode eviction or extent cloning. Consider the following example:
1) We are currently at transaction N;
2) We write to the file range [0, 1MiB);
3) Writeback finishes for the whole range and ordered extents complete,
while we are still at transaction N;
4) The inode is evicted;
5) We open the file for writing, causing the inode to be loaded to
memory again, which sets the 'full sync' bit on its flags. At this
point the inode's list of modified extent maps is empty (figuring
out which extents were created in the current transaction and were
not yet logged by an fsync is expensive, that's why we set the
'full sync' bit when loading an inode);
6) We write to the file range [512KiB, 768KiB);
7) We do a ranged fsync (such as msync()) for file range [512KiB, 768KiB).
This correctly flushes this range and logs its extent into the log
tree. When the writeback started an extent map for range [512KiB, 768KiB)
was added to the inode's list of modified extents, and when the fsync()
finishes logging it removes that extent map from the list of modified
extent maps. This fsync also clears the 'full sync' bit;
8) We do a regular fsync() (full ranged). This fsync() ends up doing
nothing because the inode's list of modified extents is empty and
no other changes happened since the previous ranged fsync(), so
it just returns success (0) and we end up never logging extents for
the file ranges [0, 512KiB) and [768KiB, 1MiB).
Another scenario where this can happen is if we replace steps 2 to 4 with
cloning from another file into our test file, as that sets the 'full sync'
bit in our inode's flags and does not populate its list of modified extent
maps.
This was causing test case generic/457 to fail sporadically when using the
NO_HOLES feature, as it exercised this later case where the inode has the
'full sync' bit set and has no extent maps in memory to represent the new
extents due to extent cloning.
Fix this by reverting commit 0a8068a3dd ("btrfs: make ranged full fsyncs
more efficient") since there is no easy way to work around it.
Fixes: 0a8068a3dd ("btrfs: make ranged full fsyncs more efficient")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When not using the NO_HOLES feature we were not marking the destination's
file range as written after cloning an inline extent into it. This can
lead to a data loss if the current destination file size is smaller than
the source file's size.
Example:
$ mkfs.btrfs -f -O ^no-holes /dev/sdc
$ mount /mnt/sdc /mnt
$ echo "hello world" > /mnt/foo
$ cp --reflink=always /mnt/foo /mnt/bar
$ rm -f /mnt/foo
$ umount /mnt
$ mount /mnt/sdc /mnt
$ cat /mnt/bar
$
$ stat -c %s /mnt/bar
0
# -> the file is empty, since we deleted foo, the data lost is forever
Fix that by calling btrfs_inode_set_file_extent_range() after cloning an
inline extent.
A test case for fstests will follow soon.
Link: https://lore.kernel.org/linux-btrfs/20200404193846.GA432065@latitude/
Reported-by: Johannes Hirte <johannes.hirte@datenkhaos.de>
Fixes: 9ddc959e80 ("btrfs: use the file extent tree infrastructure")
Tested-by: Johannes Hirte <johannes.hirte@datenkhaos.de>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Previously we would set the reloc root's last snapshot to transid - 1.
However there was a problem with doing this, and we changed it to
setting the last snapshot to the generation of the commit node of the fs
root.
This however broke should_ignore_root(). The assumption is that if we
are in a generation newer than when the reloc root was created, then we
would find the reloc root through normal backref lookups, and thus can
ignore any fs roots we find with an old enough reloc root.
Now that the last snapshot could be considerably further in the past
than before, we'd end up incorrectly ignoring an fs root. Thus we'd
find no nodes for the bytenr we were searching for, and we'd fail to
relocate anything. We'd loop through the relocate code again and see
that there were still used space in that block group, attempt to
relocate those bytenr's again, fail in the same way, and just loop like
this forever. This is tricky in that we have to not modify the fs root
at all during this time, so we need to have a block group that has data
in this fs root that is not shared by any other root, which is why this
has been difficult to reproduce.
Fixes: 054570a1dc ("Btrfs: fix relocation incorrectly dropping data references")
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Ordered ops are started twice in sync file, once outside of inode mutex
and once inside, taking the dio semaphore. There was one error path
missing the semaphore unlock.
Fixes: aab15e8ec2 ("Btrfs: fix rare chances for data loss when doing a fast fsync")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ add changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
snprintf() is a hard-to-use function, and it's especially difficult to
use it properly for concatenating substrings in a buffer with a limited
size. Since snprintf() returns the would-be-output size, not the actual
size, the subsequent use of snprintf() may point to the incorrect
position easily. Also, returning the value from snprintf() directly to
sysfs show function would pass a bogus value that is higher than the
actually truncated string.
That said, although the current code doesn't actually overflow the
buffer with PAGE_SIZE, it's a usage that shouldn't be done. Or it's
worse; this gives a wrong confidence as if it were doing safe
operations.
This patch replaces such snprintf() calls with a safer version,
scnprintf(). It returns the actual output size, hence it's more
intuitive and the code does what's expected.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Zygo reported a deadlock where a task was stuck in the inode logical
resolve code. The deadlock looks like this
Task 1
btrfs_ioctl_logical_to_ino
->iterate_inodes_from_logical
->iterate_extent_inodes
->path->search_commit_root isn't set, so a transaction is started
->resolve_indirect_ref for a root that's being deleted
->search for our key, attempt to lock a node, DEADLOCK
Task 2
btrfs_drop_snapshot
->walk down to a leaf, lock it, walk up, lock node
->end transaction
->start transaction
-> wait_cur_trans
Task 3
btrfs_commit_transaction
->wait_event(cur_trans->write_wait, num_writers == 1) DEADLOCK
We are holding a transaction open in btrfs_ioctl_logical_to_ino while we
try to resolve our references. btrfs_drop_snapshot() holds onto its
locks while it stops and starts transaction handles, because it assumes
nobody is going to touch the root now. Commit just does what commit
does, waiting for the writers to finish, blocking any new trans handles
from starting.
Fix this by making the backref code not try to resolve backrefs of roots
that are currently being deleted. This will keep us from walking into a
snapshot that's currently being deleted.
This problem was harder to hit before because we rarely broke out of the
snapshot delete halfway through, but with my delayed ref throttling code
it happened much more often. However we've always been able to do this,
so it's not a new problem.
Fixes: 8da6d5815c ("Btrfs: added btrfs_find_all_roots()")
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We always search the commit root of the extent tree for looking up back
references, however we track the reloc roots based on their current
bytenr.
This is wrong, if we commit the transaction between relocating tree
blocks we could end up in this code in build_backref_tree
if (key.objectid == key.offset) {
/*
* Only root blocks of reloc trees use backref
* pointing to itself.
*/
root = find_reloc_root(rc, cur->bytenr);
ASSERT(root);
cur->root = root;
break;
}
find_reloc_root() is looking based on the bytenr we had in the commit
root, but if we've COWed this reloc root we will not find that bytenr,
and we will trip over the ASSERT(root).
Fix this by using the commit_root->start bytenr for indexing the commit
root. Then we change the __update_reloc_root() caller to be used when
we switch the commit root for the reloc root during commit.
This fixes the panic I was seeing when we started throttling relocation
for delayed refs.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are two bugs here, but fixing them independently would just result
in pain if you happened to bisect between the two patches.
First is how we handle the -EAGAIN from relocate_tree_block(). We don't
set error, unless we happen to be the first node, which makes no sense,
I have no idea what the code was trying to accomplish here.
We in fact _do_ want err set here so that we know we need to restart in
relocate_block_group(). Also we need finish_pending_nodes() to not
actually call link_to_upper(), because we didn't actually relocate the
block.
And then if we do get -EAGAIN we do not want to set our backref cache
last_trans to the one before ours. This would force us to update our
backref cache if we didn't cross transaction ids, which would mean we'd
have some nodes updated to their new_bytenr, but still able to find
their old bytenr because we're searching the same commit root as the
last time we went through relocate_tree_blocks.
Fixing these two things keeps us from panicing when we start breaking
out of relocate_tree_blocks() either for delayed ref flushing or enospc.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since we're not only checking for metadata reservations but also if we
need to throttle our delayed ref generation, reorder
reserve_metadata_space() above the select_one_root() call in
relocate_tree_block().
The reason we want this is because select_reloc_root() will mess with
the backref cache, and if we're going to bail we want to be able to
cleanly remove this node from the backref cache and come back along to
regenerate it. Move it up so this is the first thing we do to make
restarting cleaner.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Here we are just searching down to the bytenr we're building the backref
tree for, and all of it's paths to the roots. These bytenrs are not
guaranteed to be anywhere near each other, so readahead just generates
extra latency.
Reviewed-by: Qu Wenruo <wqu@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>
Readahead will generate a lot of extra reads for adjacent nodes, but
when running delayed refs we have no idea if the next ref is going to be
adjacent or not, so this potentially just generates a lot of extra IO.
To make matters worse each ref is truly just looking for one item, it
doesn't generally search forward, so we simply don't need it here.
Reviewed-by: Qu Wenruo <wqu@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>
With BTRFS_SUBVOL_CREATE_ASYNC support remove it's no longer required to
pass the async_transid parameter so remove it and any code using it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_ioctl_snap_create_transid no longer takes a transid argument, so
remove it and rename the function to __btrfs_ioctl_snap_create to
reflect it's an internal, worker function.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This functionality was deprecated in kernel 5.4. Since no one has
complained of the impending removal it's time we did so.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have proper root ref counting everywhere we can kill the
subvol_srcu.
* removal of fs_info::subvol_srcu reduces size of fs_info by 1176 bytes
* the refcount_t used for the references checks for accidental 0->1
in cases where the root lifetime would not be properly protected
* there's a leak detector for roots to catch unfreed roots at umount
time
* SRCU served us well over the years but is was not a proper
synchronization mechanism for some cases
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
The radix root is primarily protected by the fs_roots_radix_lock, so use
that to lookup and get a ref on all of our fs roots in
btrfs_cleanup_fs_roots. The tree reference is taken in the protected
section as before.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that all the users of roots take references for them we can drop the
extra root ref we've been taking. Before we had roots at 2 refs for the
life of the file system, one for the radix tree, and one simply for
existing. Now that we have proper ref accounting in all places that use
roots we can drop this extra ref simply for existing as we no longer
need it.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At the point we add a root to the dead roots list we have no open inodes
for that root, so we need to hold a ref on that root to keep it from
disappearing.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we make sure all the inodes have refs on their root we don't have to
worry about the root disappearing while we have open inodes.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are a few different ways to free roots, either you allocated them
yourself and you just do
free_extent_buffer(root->node);
free_extent_buffer(root->commit_node);
btrfs_put_root(root);
Which is the pattern for log roots. Or for snapshots/subvolumes that
are being dropped you simply call btrfs_free_fs_root() which does all
the cleanup for you.
Unify this all into btrfs_put_root(), so that we don't free up things
associated with the root until the last reference is dropped. This
makes the root freeing code much more significant.
The only caveat is at close_ctree() time we have to free the extent
buffers for all of our main roots (extent_root, chunk_root, etc) because
we have to drop the btree_inode and we'll run into issues if we hold
onto those nodes until ->kill_sb() time. This will be addressed in the
future when we kill the btree_inode.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We are going to make root life be controlled soley by refcounting, and
inodes will be one of the things that hold a ref on the root. This
means we need to handle dropping the ino_cache_inode outside of the root
freeing logic, so move it into btrfs_drop_and_free_fs_root() so it is
cleaned up properly on unmount.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I'm going to make the entire destruction of btrfs_root's controlled by
their refcount, so it will be helpful to notice if we're leaking their
eb's on umount.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This was pretty subtle, we default to reloc roots having 0 root refs, so
if we crash in the middle of the relocation they can just be deleted.
If we successfully complete the relocation operations we'll set our root
refs to 1 in prepare_to_merge() and then go on to merge_reloc_roots().
At prepare_to_merge() time if any of the reloc roots have a 0 reference
still, we will remove that reloc root from our reloc root rb tree, and
then clean it up later.
However this only happens if we successfully start a transaction. If
we've aborted previously we will skip this step completely, and only
have reloc roots with a reference count of 0, but were never properly
removed from the reloc control's rb tree.
This isn't a problem per-se, our references are held by the list the
reloc roots are on, and by the original root the reloc root belongs to.
If we end up in this situation all the reloc roots will be added to the
dirty_reloc_list, and then properly dropped at that point. The reloc
control will be free'd and the rb tree is no longer used.
There were two options when fixing this, one was to remove the BUG_ON(),
the other was to make prepare_to_merge() handle the case where we
couldn't start a trans handle.
IMO this is the cleaner solution. I started with handling the error in
prepare_to_merge(), but it turned out super ugly. And in the end this
BUG_ON() simply doesn't matter, the cleanup was happening properly, we
were just panicing because this BUG_ON() only matters in the success
case. So I've opted to just remove it and add a comment where it was.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We previously were relying on root->reloc_root to be cleaned up by the
drop snapshot, or the error handling. However if btrfs_drop_snapshot()
failed it wouldn't drop the ref for the root. Also we sort of depend on
the right thing to happen with moving reloc roots between lists and the
fs root they belong to, which makes it hard to figure out who owns the
reference.
Fix this by explicitly holding a reference on the reloc root for
roo->reloc_root. This means that we hold two references on reloc roots,
one for whichever reloc_roots list it's attached to, and the
root->reloc_root we're on.
This makes it easier to reason out who owns a reference on the root, and
when it needs to be dropped.
Reviewed-by: Qu Wenruo <wqu@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>
The DEAD_RELOC_TREE flag is in place in order to avoid a use after free
in init_reloc_root, tracking the presence of reloc_root. However adding
the explicit tree references in previous patches makes the use after
free impossible because at this point we no longer have a reloc_control
set on the fs_info and thus cannot enter the function.
So move this to be coupled with clearing the root->reloc_root so we're
consistent with all other operations of the reloc root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
If we have an error while processing the reloc roots we could leak roots
that were added to rc->reloc_roots before we hit the error. We could
have also not removed the reloc tree mapping from our rb_tree, so clean
up any remaining nodes in the reloc root rb_tree.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ use rbtree_postorder_for_each_entry_safe ]
Signed-off-by: David Sterba <dsterba@suse.com>
We previously were checking if the root had a dead root before accessing
root->reloc_root in order to avoid a use-after-free type bug. However
this scenario happens after we've unset the reloc control, so we would
have been saved if we'd simply checked for fs_info->reloc_control. At
this point during relocation we no longer need to be creating new reloc
roots, so simply move this check above the reloc_root checks to avoid
any future races and confusion.
Reviewed-by: Qu Wenruo <wqu@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>
If we do merge_reloc_roots() we could insert a few roots onto the dirty
subvol roots list, where we hold a ref on them. If we fail to start the
transaction we need to run clean_dirty_subvols() in order to cleanup the
refs.
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>
If we fail to load an fs root, or fail to start a transaction we can
bail without unsetting the reloc control, which leads to problems later
when we free the reloc control but still have it attached to the file
system.
In the normal path we'll end up calling unset_reloc_control() twice, but
all it does is set fs_info->reloc_control = NULL, and we can only have
one balance at a time so it's not racey.
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@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>
If we have an error while building the backref tree in relocation we'll
process all the pending edges and then free the node. However if we
integrated some edges into the cache we'll lose our link to those edges
by simply freeing this node, which means we'll leak memory and
references to any roots that we've found.
Instead we need to use remove_backref_node(), which walks through all of
the edges that are still linked to this node and free's them up and
drops any root references we may be holding.
CC: stable@vger.kernel.org # 4.9+
Reviewed-by: Qu Wenruo <wqu@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>
In relocation, we need to locate all parent tree leaves referring to one
data extent, thus we have a complex mechanism to iterate throught extent
tree and subvolume trees to locate the related leaves.
However this is already done in backref.c, we have
btrfs_find_all_leafs(), which can return a ulist containing all leaves
referring to that data extent.
Use btrfs_find_all_leafs() to replace find_data_references().
There is a special handling for v1 space cache data extents, where we
need to delete the v1 space cache data extents, to avoid those data
extents to hang the data relocation.
In this patch, the special handling is done by re-iterating the root
tree leaf. Although it's a little less efficient than the old handling,
considering we can reuse a lot of code, it should be acceptable.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While debugging I noticed I wasn't getting ref verify errors before
everything blew up. Turns out it's because we don't warn when we try to
add a normal ref via btrfs_inc_ref() if the block entry exists but has 0
references. This is incorrect, we should never be doing anything other
than adding a new extent once a block entry drops to 0 references.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 0c713cbab6 ("Btrfs: fix race between ranged fsync and writeback
of adjacent ranges") fixed a bug where we could end up with file extent
items in a log tree that represent file ranges that overlap due to a race
between the hole detection of a ranged full fsync and writeback for a
different file range.
The problem was solved by forcing any ranged full fsync to become a
non-ranged full fsync - setting the range start to 0 and the end offset to
LLONG_MAX. This was a simple solution because the code that detected and
marked holes was very complex, it used to be done at copy_items() and
implied several searches on the fs/subvolume tree. The drawback of that
solution was that we started to flush delalloc for the entire file and
wait for all the ordered extents to complete for ranged full fsyncs
(including ordered extents covering ranges completely outside the given
range). Fortunatelly ranged full fsyncs are not the most common case
(hopefully for most workloads).
However a later fix for detecting and marking holes was made by commit
0e56315ca1 ("Btrfs: fix missing hole after hole punching and fsync
when using NO_HOLES") and it simplified a lot the detection of holes,
and now copy_items() no longer does it and we do it in a much more simple
way at btrfs_log_holes().
This makes it now possible to simply make the code that detects holes to
operate only on the initial range and no longer need to operate on the
whole file, while also avoiding the need to flush delalloc for the entire
file and wait for ordered extents that cover ranges that don't overlap the
given range.
Another special care is that we must skip file extent items that fall
entirely outside the fsync range when copying inode items from the
fs/subvolume tree into the log tree - this is to avoid races with ordered
extent completion for extents falling outside the fsync range, which could
cause us to end up with file extent items in the log tree that have
overlapping ranges - for example if the fsync range is [1Mb, 2Mb], when
we copy inode items we could copy an extent item for the range [0, 512K],
then release the search path and before moving to the next leaf, an
ordered extent for a range of [256Kb, 512Kb] completes - this would
cause us to copy the new extent item for range [256Kb, 512Kb] into the
log tree after we have copied one for the range [0, 512Kb] - the extents
overlap, resulting in a corruption.
So this change just does these steps:
1) When the NO_HOLES feature is enabled it leaves the initial range
intact - no longer sets it to [0, LLONG_MAX] when the full sync bit
is set in the inode. If NO_HOLES is not enabled, always set the range
to a full, just like before this change, to avoid missing file extent
items representing holes after replaying the log (for both full and
fast fsyncs);
2) Make the hole detection code to operate only on the fsync range;
3) Make the code that copies items from the fs/subvolume tree to skip
copying file extent items that cover a range completely outside the
range of the fsync.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function btrfs_log_inode() is quite large and so is its loop which
iterates the inode items from the fs/subvolume tree and copies them into
a log tree. Because this is a large loop inside a very large function
and because an upcoming patch in this series needs to add some more logic
inside that loop, move the loop into a helper function to make it a bit
more manageable.
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>
Getting the end offset for a file extent item requires a bit of code since
the extent can be either inline or regular/prealloc. There are some places
all over the code base that open code this logic and in another patch
later in this series it will be needed again. Therefore encapsulate this
logic in a helper function and use it.
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>
When doing a fast fsync for a range that starts at an offset greater than
zero, we can end up with a log that when replayed causes the respective
inode miss a file extent item representing a hole if we are not using the
NO_HOLES feature. This is because for fast fsyncs we don't log any extents
that cover a range different from the one requested in the fsync.
Example scenario to trigger it:
$ mkfs.btrfs -O ^no-holes -f /dev/sdd
$ mount /dev/sdd /mnt
# Create a file with a single 256K and fsync it to clear to full sync
# bit in the inode - we want the msync below to trigger a fast fsync.
$ xfs_io -f -c "pwrite -S 0xab 0 256K" -c "fsync" /mnt/foo
# Force a transaction commit and wipe out the log tree.
$ sync
# Dirty 768K of data, increasing the file size to 1Mb, and flush only
# the range from 256K to 512K without updating the log tree
# (sync_file_range() does not trigger fsync, it only starts writeback
# and waits for it to finish).
$ xfs_io -c "pwrite -S 0xcd 256K 768K" /mnt/foo
$ xfs_io -c "sync_range -abw 256K 256K" /mnt/foo
# Now dirty the range from 768K to 1M again and sync that range.
$ xfs_io -c "mmap -w 768K 256K" \
-c "mwrite -S 0xef 768K 256K" \
-c "msync -s 768K 256K" \
-c "munmap" \
/mnt/foo
<power fail>
# Mount to replay the log.
$ mount /dev/sdd /mnt
$ umount /mnt
$ btrfs check /dev/sdd
Opening filesystem to check...
Checking filesystem on /dev/sdd
UUID: 482fb574-b288-478e-a190-a9c44a78fca6
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
[4/7] checking fs roots
root 5 inode 257 errors 100, file extent discount
Found file extent holes:
start: 262144, len: 524288
ERROR: errors found in fs roots
found 720896 bytes used, error(s) found
total csum bytes: 512
total tree bytes: 131072
total fs tree bytes: 32768
total extent tree bytes: 16384
btree space waste bytes: 123514
file data blocks allocated: 589824
referenced 589824
Fix this issue by setting the range to full (0 to LLONG_MAX) when the
NO_HOLES feature is not enabled. This results in extra work being done
but it gives the guarantee we don't end up with missing holes after
replaying the log.
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of iterating all pending tickets on the normal/priority list to
sum their total size the cost can be amortized across ticket addition/
removal. This turns O(n) + O(m) (where n is the size of the normal list
and m of the priority list) into O(1). This will mostly have effect in
workloads that experience heavy flushing.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs doesn't provide a migratepage callback for data pages.
It means that fallback_migrate_page() is used to migrate btrfs pages.
fallback_migrate_page() cannot move dirty pages, instead it tries to
flush them (in sync mode) or just fails (in async mode).
In the sync mode pages which are scheduled to be processed by
btrfs_writepage_fixup_worker() can't be effectively flushed by the
migration code, because there is no established way to wait for the
completion of the delayed work.
It all leads to page migration failures.
To fix it the patch implements a btrs-specific migratepage callback,
which is similar to iomap_migrate_page() used by some other fs, except
it does take care of the PagePrivate2 flag which is used for data
ordering purposes.
Reviewed-by: Chris Mason <clm@fb.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's no longer used following 30d40577e3 ("btrfs: reloc: Also queue
orphan reloc tree for cleanup to avoid BUG_ON()"), so just remove it.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the non-prefixed version is a simple wrapper used to hide
the 4th argument of the prefixed version. This doesn't bring much value
in practice and only makes the code harder to follow by adding another
level of indirection. Rectify this by removing the __ prefix and
have only one public function to release bytes from a block reservation.
No semantic changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When relocating data block groups with tons of small extents, or large
metadata block groups, there can be over 200,000 extents.
We will iterate all extents of such block group in relocate_block_group(),
where iteration itself can be kinda time-consuming.
So when user want to cancel the balance, the extent iteration loop can
be another target.
This patch will add the cancelling check in the extent iteration loop of
relocate_block_group() to make balance cancelling faster.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When relocating a data extents with large large data extents, we spend
most of our time in relocate_file_extent_cluster() at stage "moving data
extents":
1) | btrfs_relocate_block_group [btrfs]() {
1) | relocate_file_extent_cluster [btrfs]() {
1) $ 6586769 us | }
1) + 18.260 us | relocate_file_extent_cluster [btrfs]();
1) + 15.770 us | relocate_file_extent_cluster [btrfs]();
1) $ 8916340 us | }
1) | btrfs_relocate_block_group [btrfs]() {
1) | relocate_file_extent_cluster [btrfs]() {
1) $ 11611586 us | }
1) + 16.930 us | relocate_file_extent_cluster [btrfs]();
1) + 15.870 us | relocate_file_extent_cluster [btrfs]();
1) $ 14986130 us | }
To make data relocation cancelling quicker, add extra balance cancelling
check after each page read in relocate_file_extent_cluster().
Cleanup and error handling uses the same mechanism as if the whole
process finished
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce a new error injection point, should_cancel_balance().
It's just a wrapper of atomic_read(&fs_info->balance_cancel_req), but
allows us to override the return value.
Currently there are only one locations using this function:
- btrfs_balance()
It checks cancel before each block group.
There are other locations checking fs_info->balance_cancel_req, but they
are not used as an indicator to exit, so there is no need to use the
wrapper.
But there will be more locations coming, and some locations can cause
kernel panic if not handled properly. So introduce this error injection
to provide better test interface.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are a few cases where we don't allow cloning an inline extent into
the destination inode, returning -EOPNOTSUPP to user space. This was done
to prevent several types of file corruption and because it's not very
straightforward to deal with these cases, as they can't rely on simply
copying the inline extent between leaves. Such cases require copying the
inline extent's data into the respective page of the destination inode.
Not supporting these cases makes it harder and more cumbersome to write
applications/libraries that work on any filesystem with reflink support,
since all these cases for which btrfs fails with -EOPNOTSUPP work just
fine on xfs for example. These unsupported cases are also not documented
anywhere and explaining which exact cases fail require a bit of too
technical understanding of btrfs's internal (inline extents and when and
where can they exist in a file), so it's not really user friendly.
Also some test cases from fstests that use fsx, such as generic/522 for
example, can sporadically fail because they trigger one of these cases,
and fsx expects all operations to succeed.
This change adds supports for cloning all these cases by copying the
inline extent's data into the respective page of the destination inode.
With this change test case btrfs/112 from fstests fails because it
expects some clone operations to fail, so it will be updated. Also a
new test case that exercises all these previously unsupported cases
will be added to fstests.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can not reflink parts of an inline extent, we must always reflink the
whole inline extent. We know that inline extents always start at file
offset 0 and that can never represent an amount of data larger then the
filesystem's sector size (both compressed and uncompressed). We also have
had the constraints that reflink operations must have a start offset that
is aligned to the sector size and an end offset that is also aligned or
it ends the inode's i_size, so there's no way for user space to be able
to do a reflink operation that will refer to only a part of an inline
extent.
Initially there was a bug in the inlining code that could allow compressed
inline extents that encoded more than 1 page, but that was fixed in 2008
by commit 70b99e6959 ("Btrfs: Compression corner fixes") since that
was problematic.
So remove all the extent cloning code that deals with the possibility
of cloning only partial inline extents.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The reflink code is quite large and has been living in ioctl.c since ever.
It has grown over the years after many bug fixes and improvements, and
since I'm planning on making some further improvements on it, it's time
to get it better organized by moving into its own file, reflink.c
(similar to what xfs does for example).
This change only moves the code out of ioctl.c into the new file, it
doesn't do any other change.
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>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero." [1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero." [1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array
member[1][2], introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero." [1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The space_info list is normally RCU protected and should be traversed
with rcu_read_lock held. There's a warning
[29.104756] WARNING: suspicious RCU usage
[29.105046] 5.6.0-rc4-next-20200305 #1 Not tainted
[29.105231] -----------------------------
[29.105401] fs/btrfs/block-group.c:2011 RCU-list traversed in non-reader section!!
pointing out that the locking is missing in btrfs_read_block_groups.
However this is not necessary as the list traversal happens at mount
time when there's no other thread potentially accessing the list.
To fix the warning and for consistency let's add the RCU lock/unlock,
the code won't be affected much as it's doing some lightweight
operations.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
No need to add a level of indirection for hiding a simple 'if'. Open
code insert_extent_backref in its sole caller. No functional changes.
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>
relocate_tree_blocks calls get_tree_block_key for a block iff that block
has its ->key_ready equal false. Thus the BUG_ON in the latter function
cannot ever be triggered so remove it.
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>
The validation follows the same steps for all three block group types,
the existing helper validate_convert_profile can be enhanced and do more
of the common things.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that csum_tree_block is not returning any errors, we can make
csum_tree_block return void and simplify callers.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Thw whole point of csum_tree_block is to iterate over all extent buffer
pages and pass it to checksumming functions. The bytes where checksum is
stored must be skipped, thus map_private_extent_buffer. This complicates
further offset calculations.
As the first page will be always present, checksum the relevant bytes
unconditionally and then do a simple iteration over the remaining pages.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There's an unnecessary indirection in the checksum definition table,
pointer and the string itself. The strings are short and the overall
size of one entry is now 24 bytes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Having btrfs_alloc_chunk doesn't bring any value since it
encapsulates a lockdep assert and a call to find_next_chunk. Simply
rename the internal __btrfs_alloc_chunk function to the public one
and remove it's 2nd parameter as all callers always pass the return
value of find_next_chunk. Finally, migrate the call to
lockdep_assert_held so as to not lose the check.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I noticed while running my snapshot torture test that we were getting a
lot of metadata chunks allocated with very little actually used.
Digging into this we would commit the transaction, still not have enough
space, and then force a chunk allocation.
I noticed that we were barely flushing any delalloc at all, despite the
fact that we had around 13gib of outstanding delalloc reservations. It
turns out this is because of our btrfs_calc_reclaim_metadata_size()
calculation. It _only_ takes into account the outstanding ticket sizes,
which isn't the whole story. In this particular workload we're slowly
filling up the disk, which means our overcommit space will suddenly
become a lot less, and our outstanding reservations will be well more
than what we can handle. However we are only flushing based on our
ticket size, which is much less than we need to actually reclaim.
So fix btrfs_calc_reclaim_metadata_size() to take into account the
overage in the case that we've gotten less available space suddenly.
This makes it so we attempt to reclaim a lot more delalloc space, which
allows us to make our reservations and we no longer are allocating a
bunch of needless metadata chunks.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
During unmount we can have a job from the delayed inode items work queue
still running, that can lead to at least two bad things:
1) A crash, because the worker can try to create a transaction just
after the fs roots were freed;
2) A transaction leak, because the worker can create a transaction
before the fs roots are freed and just after we committed the last
transaction and after we stopped the transaction kthread.
A stack trace example of the crash:
[79011.691214] kernel BUG at lib/radix-tree.c:982!
[79011.692056] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[79011.693180] CPU: 3 PID: 1394 Comm: kworker/u8:2 Tainted: G W 5.6.0-rc2-btrfs-next-54 #2
(...)
[79011.696789] Workqueue: btrfs-delayed-meta btrfs_work_helper [btrfs]
[79011.697904] RIP: 0010:radix_tree_tag_set+0xe7/0x170
(...)
[79011.702014] RSP: 0018:ffffb3c84a317ca0 EFLAGS: 00010293
[79011.702949] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[79011.704202] RDX: ffffb3c84a317cb0 RSI: ffffb3c84a317ca8 RDI: ffff8db3931340a0
[79011.705463] RBP: 0000000000000005 R08: 0000000000000005 R09: ffffffff974629d0
[79011.706756] R10: ffffb3c84a317bc0 R11: 0000000000000001 R12: ffff8db393134000
[79011.708010] R13: ffff8db3931340a0 R14: ffff8db393134068 R15: 0000000000000001
[79011.709270] FS: 0000000000000000(0000) GS:ffff8db3b6a00000(0000) knlGS:0000000000000000
[79011.710699] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[79011.711710] CR2: 00007f22c2a0a000 CR3: 0000000232ad4005 CR4: 00000000003606e0
[79011.712958] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[79011.714205] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[79011.715448] Call Trace:
[79011.715925] record_root_in_trans+0x72/0xf0 [btrfs]
[79011.716819] btrfs_record_root_in_trans+0x4b/0x70 [btrfs]
[79011.717925] start_transaction+0xdd/0x5c0 [btrfs]
[79011.718829] btrfs_async_run_delayed_root+0x17e/0x2b0 [btrfs]
[79011.719915] btrfs_work_helper+0xaa/0x720 [btrfs]
[79011.720773] process_one_work+0x26d/0x6a0
[79011.721497] worker_thread+0x4f/0x3e0
[79011.722153] ? process_one_work+0x6a0/0x6a0
[79011.722901] kthread+0x103/0x140
[79011.723481] ? kthread_create_worker_on_cpu+0x70/0x70
[79011.724379] ret_from_fork+0x3a/0x50
(...)
The following diagram shows a sequence of steps that lead to the crash
during ummount of the filesystem:
CPU 1 CPU 2 CPU 3
btrfs_punch_hole()
btrfs_btree_balance_dirty()
btrfs_balance_delayed_items()
--> sees
fs_info->delayed_root->items
with value 200, which is greater
than
BTRFS_DELAYED_BACKGROUND (128)
and smaller than
BTRFS_DELAYED_WRITEBACK (512)
btrfs_wq_run_delayed_node()
--> queues a job for
fs_info->delayed_workers to run
btrfs_async_run_delayed_root()
btrfs_async_run_delayed_root()
--> job queued by CPU 1
--> starts picking and running
delayed nodes from the
prepare_list list
close_ctree()
btrfs_delete_unused_bgs()
btrfs_commit_super()
btrfs_join_transaction()
--> gets transaction N
btrfs_commit_transaction(N)
--> set transaction state
to TRANTS_STATE_COMMIT_START
btrfs_first_prepared_delayed_node()
--> picks delayed node X through
the prepared_list list
btrfs_run_delayed_items()
btrfs_first_delayed_node()
--> also picks delayed node X
but through the node_list
list
__btrfs_commit_inode_delayed_items()
--> runs all delayed items from
this node and drops the
node's item count to 0
through call to
btrfs_release_delayed_inode()
--> finishes running any remaining
delayed nodes
--> finishes transaction commit
--> stops cleaner and transaction threads
btrfs_free_fs_roots()
--> frees all roots and removes them
from the radix tree
fs_info->fs_roots_radix
btrfs_join_transaction()
start_transaction()
btrfs_record_root_in_trans()
record_root_in_trans()
radix_tree_tag_set()
--> crashes because
the root is not in
the radix tree
anymore
If the worker is able to call btrfs_join_transaction() before the unmount
task frees the fs roots, we end up leaking a transaction and all its
resources, since after the call to btrfs_commit_super() and stopping the
transaction kthread, we don't expect to have any transaction open anymore.
When this situation happens the worker has a delayed node that has no
more items to run, since the task calling btrfs_run_delayed_items(),
which is doing a transaction commit, picks the same node and runs all
its items first.
We can not wait for the worker to complete when running delayed items
through btrfs_run_delayed_items(), because we call that function in
several phases of a transaction commit, and that could cause a deadlock
because the worker calls btrfs_join_transaction() and the task doing the
transaction commit may have already set the transaction state to
TRANS_STATE_COMMIT_DOING.
Also it's not possible to get into a situation where only some of the
items of a delayed node are added to the fs/subvolume tree in the current
transaction and the remaining ones in the next transaction, because when
running the items of a delayed inode we lock its mutex, effectively
waiting for the worker if the worker is running the items of the delayed
node already.
Since this can only cause issues when unmounting a filesystem, fix it in
a simple way by waiting for any jobs on the delayed workers queue before
calling btrfs_commit_supper() at close_ctree(). This works because at this
point no one can call btrfs_btree_balance_dirty() or
btrfs_balance_delayed_items(), and if we end up waiting for any worker to
complete, btrfs_commit_super() will commit the transaction created by the
worker.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function finally factor out prepare_allocation() form
find_free_extent(). This function is called before the allocation loop
and a specific allocator function like prepare_allocation_clustered()
should initialize their private information and can set proper hint_byte
to indicate where to start the allocation with.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
LOOP_NO_EMPTY_SIZE is solely dedicated for clustered allocation. So, we
can skip this stage and give up the allocation.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out chunk_allocation_failed() from
find_free_extent_update_loop(). This function is called when it failed
to allocate a chunk. The function can modify "ffe_ctl->loop" and return
0 to continue with the next stage. Or, it can return -ENOSPC to give up
here.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that, we don't use last_ptr and use_cluster in the function. Drop
these arguments from it.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out found_extent() from find_free_extent_update_loop(). This
function is called when a proper extent is found and before returning
from find_free_extent(). Hook functions like found_extent_clustered()
should save information for a next allocation.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out release_block_group() from find_free_extent(). This function
is called when it gives up an allocation from a block group. Each
allocation policy should reset its information for an allocation in
the next block group.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that, find_free_extent_clustered() and find_free_extent_unclustered()
can access "last_ptr" from the "clustered" variable, we can drop it from
the arguments.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out do_allocation() from find_free_extent(). This function do an
actual extent allocation in a given block group. The ffe_ctl->policy is
used to determine the actual allocator function to use.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move "last_ptr" and "use_cluster" into struct find_free_extent_ctl, so
that hook functions for clustered allocator can use these variables.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit moves hint_byte into find_free_extent_ctl, so that we can
modify the hint_byte in the other functions. This will help us split
find_free_extent further. This commit also renames the function argument
"hint_byte" to "hint_byte_orig" to avoid misuse.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit introduces extent allocation policy for btrfs. This policy
controls how btrfs allocate an extents from block groups. There is no
functional change introduced with this commit.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, we ignore a device whose available space is less than
"BTRFS_STRIPE_LEN * dev_stripes". This is a lower limit for current
allocation policy (to maximize the number of stripes). This commit
parameterizes dev_extent_min, so that other policies can set their own
lower limitat to ignore a device with insufficient space.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out create_chunk() from __btrfs_alloc_chunk(). This function
finally creates a chunk. There is no functional changes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out decide_stripe_size() from __btrfs_alloc_chunk(). This
function calculates the actual stripe size to allocate.
decide_stripe_size() handles the common case to round down the 'ndevs'
to 'devs_increment' and check the upper and lower limitation of 'ndevs'.
decide_stripe_size_regular() decides the size of a stripe and the size
of a chunk. The policy is to maximize the number of stripes.
This commit has no functional changes.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out gather_device_info() from __btrfs_alloc_chunk(). This
function iterates over devices list and gather information about
devices. This commit also introduces "max_avail" and
"dev_extent_min" to fold the same calculation to one variable.
This commit has no functional changes.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out init_alloc_chunk_ctl() from __btrfs_alloc_chunk(). This
function initialises parameters of "struct alloc_chunk_ctl" for
allocation. init_alloc_chunk_ctl() handles a common part of the
initialisation to load the RAID parameters from btrfs_raid_array.
init_alloc_chunk_ctl_policy_regular() decides some parameters for its
allocation.
The last "else" case in the original code is moved to
__btrfs_alloc_chunk() to handle the error case in the common code.
Replace the BUG_ON with ASSERT() and error return at the same time.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce "struct alloc_chunk_ctl" to wrap needed parameters for the
chunk allocation. This will be used to split __btrfs_alloc_chunk() into
smaller functions.
This commit folds a number of local variables in __btrfs_alloc_chunk()
into one "struct alloc_chunk_ctl ctl". There is no functional change.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out two functions from find_free_dev_extent_start().
dev_extent_search_start() decides the starting position of the search.
dev_extent_hole_check() checks if a hole found is suitable for device
extent allocation.
These functions also have the switch-cases to change the allocation
behavior depending on the policy.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce chunk allocation policy for btrfs. This policy controls how
chunks and device extents are allocated from devices.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Do not BUG_ON() when an invalid profile is passed to __btrfs_alloc_chunk().
Instead return -EINVAL with ASSERT() to catch a bug in the development
stage.
Suggested-by: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While the "full_search" variable defined in find_free_extent() is bool,
but the full_search argument of find_free_extent_update_loop() is
defined as int. Let's trivially fix the argument type.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
After the previous patch, qgroup_rescan_running is protected by
btrfs_fs_info::qgroup_rescan_lock, thus no need for the extra spinlock.
Suggested-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>
[BUG]
There are some reports about btrfs wait forever to unmount itself, with
the following call trace:
INFO: task umount:4631 blocked for more than 491 seconds.
Tainted: G X 5.3.8-2-default #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
umount D 0 4631 3337 0x00000000
Call Trace:
([<00000000174adf7a>] __schedule+0x342/0x748)
[<00000000174ae3ca>] schedule+0x4a/0xd8
[<00000000174b1f08>] schedule_timeout+0x218/0x420
[<00000000174af10c>] wait_for_common+0x104/0x1d8
[<000003ff804d6994>] btrfs_qgroup_wait_for_completion+0x84/0xb0 [btrfs]
[<000003ff8044a616>] close_ctree+0x4e/0x380 [btrfs]
[<0000000016fa3136>] generic_shutdown_super+0x8e/0x158
[<0000000016fa34d6>] kill_anon_super+0x26/0x40
[<000003ff8041ba88>] btrfs_kill_super+0x28/0xc8 [btrfs]
[<0000000016fa39f8>] deactivate_locked_super+0x68/0x98
[<0000000016fcb198>] cleanup_mnt+0xc0/0x140
[<0000000016d6a846>] task_work_run+0xc6/0x110
[<0000000016d04f76>] do_notify_resume+0xae/0xb8
[<00000000174b30ae>] system_call+0xe2/0x2c8
[CAUSE]
The problem happens when we have called qgroup_rescan_init(), but
not queued the worker. It can be caused mostly by error handling.
Qgroup ioctl thread | Unmount thread
----------------------------------------+-----------------------------------
|
btrfs_qgroup_rescan() |
|- qgroup_rescan_init() |
| |- qgroup_rescan_running = true; |
| |
|- trans = btrfs_join_transaction() |
| Some error happened |
| |
|- btrfs_qgroup_rescan() returns error |
But qgroup_rescan_running == true; |
| close_ctree()
| |- btrfs_qgroup_wait_for_completion()
| |- running == true;
| |- wait_for_completion();
btrfs_qgroup_rescan_worker is never queued, thus no one is going to wake
up close_ctree() and we get a deadlock.
All involved qgroup_rescan_init() callers are:
- btrfs_qgroup_rescan()
The example above. It's possible to trigger the deadlock when error
happened.
- btrfs_quota_enable()
Not possible. Just after qgroup_rescan_init() we queue the work.
- btrfs_read_qgroup_config()
It's possible to trigger the deadlock. It only init the work, the
work queueing happens in btrfs_qgroup_rescan_resume().
Thus if error happened in between, deadlock is possible.
We shouldn't set fs_info->qgroup_rescan_running just in
qgroup_rescan_init(), as at that stage we haven't yet queued qgroup
rescan worker to run.
[FIX]
Set qgroup_rescan_running before queueing the work, so that we ensure
the rescan work is queued when we wait for it.
Fixes: 8d9eddad19 ("Btrfs: fix qgroup rescan worker initialization")
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
[ Change subject and cause analyse, use a smaller fix ]
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are new types and helpers that are supposed to be used in new code.
As a preparation to get rid of legacy types and API functions do
the conversion here.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There is a fuzzed image which could cause KASAN report at unmount time.
BUG: KASAN: use-after-free in btrfs_queue_work+0x2c1/0x390
Read of size 8 at addr ffff888067cf6848 by task umount/1922
CPU: 0 PID: 1922 Comm: umount Tainted: G W 5.0.21 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Call Trace:
dump_stack+0x5b/0x8b
print_address_description+0x70/0x280
kasan_report+0x13a/0x19b
btrfs_queue_work+0x2c1/0x390
btrfs_wq_submit_bio+0x1cd/0x240
btree_submit_bio_hook+0x18c/0x2a0
submit_one_bio+0x1be/0x320
flush_write_bio.isra.41+0x2c/0x70
btree_write_cache_pages+0x3bb/0x7f0
do_writepages+0x5c/0x130
__writeback_single_inode+0xa3/0x9a0
writeback_single_inode+0x23d/0x390
write_inode_now+0x1b5/0x280
iput+0x2ef/0x600
close_ctree+0x341/0x750
generic_shutdown_super+0x126/0x370
kill_anon_super+0x31/0x50
btrfs_kill_super+0x36/0x2b0
deactivate_locked_super+0x80/0xc0
deactivate_super+0x13c/0x150
cleanup_mnt+0x9a/0x130
task_work_run+0x11a/0x1b0
exit_to_usermode_loop+0x107/0x130
do_syscall_64+0x1e5/0x280
entry_SYSCALL_64_after_hwframe+0x44/0xa9
[CAUSE]
The fuzzed image has a completely screwd up extent tree:
leaf 29421568 gen 8 total ptrs 6 free space 3587 owner EXTENT_TREE
refs 2 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 5938
item 0 key (12587008 168 4096) itemoff 3942 itemsize 53
extent refs 1 gen 9 flags 1
ref#0: extent data backref root 5 objectid 259 offset 0 count 1
item 1 key (12591104 168 8192) itemoff 3889 itemsize 53
extent refs 1 gen 9 flags 1
ref#0: extent data backref root 5 objectid 271 offset 0 count 1
item 2 key (12599296 168 4096) itemoff 3836 itemsize 53
extent refs 1 gen 9 flags 1
ref#0: extent data backref root 5 objectid 259 offset 4096 count 1
item 3 key (29360128 169 0) itemoff 3803 itemsize 33
extent refs 1 gen 9 flags 2
ref#0: tree block backref root 5
item 4 key (29368320 169 1) itemoff 3770 itemsize 33
extent refs 1 gen 9 flags 2
ref#0: tree block backref root 5
item 5 key (29372416 169 0) itemoff 3737 itemsize 33
extent refs 1 gen 9 flags 2
ref#0: tree block backref root 5
Note that leaf 29421568 doesn't have its backref in the extent tree.
Thus extent allocator can re-allocate leaf 29421568 for other trees.
In short, the bug is caused by:
- Existing tree block gets allocated to log tree
This got its generation bumped.
- Log tree balance cleaned dirty bit of offending tree block
It will not be written back to disk, thus no WRITTEN flag.
- Original owner of the tree block gets COWed
Since the tree block has higher transid, no WRITTEN flag, it's reused,
and not traced by transaction::dirty_pages.
- Transaction aborted
Tree blocks get cleaned according to transaction::dirty_pages. But the
offending tree block is not recorded at all.
- Filesystem unmount
All pages are assumed to be are clean, destroying all workqueue, then
call iput(btree_inode).
But offending tree block is still dirty, which triggers writeback, and
causes use-after-free bug.
The detailed sequence looks like this:
- Initial status
eb: 29421568, header=WRITTEN bflags_dirty=0, page_dirty=0, gen=8,
not traced by any dirty extent_iot_tree.
- New tree block is allocated
Since there is no backref for 29421568, it's re-allocated as new tree
block.
Keep in mind that tree block 29421568 is still referred by extent
tree.
- Tree block 29421568 is filled for log tree
eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 << (gen bumped)
traced by btrfs_root::dirty_log_pages
- Some log tree operations
Since the fs is using node size 4096, the log tree can easily go a
level higher.
- Log tree needs balance
Tree block 29421568 gets all its content pushed to right, thus now
it is empty, and we don't need it.
btrfs_clean_tree_block() from __push_leaf_right() get called.
eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9
traced by btrfs_root::dirty_log_pages
- Log tree write back
btree_write_cache_pages() goes through dirty pages ranges, but since
page of tree block 29421568 gets cleaned already, it's not written
back to disk. Thus it doesn't have WRITTEN bit set.
But ranges in dirty_log_pages are cleared.
eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9
not traced by any dirty extent_iot_tree.
- Extent tree update when committing transaction
Since tree block 29421568 has transid equal to running trans, and has
no WRITTEN bit, should_cow_block() will use it directly without adding
it to btrfs_transaction::dirty_pages.
eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9
not traced by any dirty extent_iot_tree.
At this stage, we're doomed. We have a dirty eb not tracked by any
extent io tree.
- Transaction gets aborted due to corrupted extent tree
Btrfs cleans up dirty pages according to transaction::dirty_pages and
btrfs_root::dirty_log_pages.
But since tree block 29421568 is not tracked by neither of them, it's
still dirty.
eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9
not traced by any dirty extent_iot_tree.
- Filesystem unmount
Since all cleanup is assumed to be done, all workqueus are destroyed.
Then iput(btree_inode) is called, expecting no dirty pages.
But tree 29421568 is still dirty, thus triggering writeback.
Since all workqueues are already freed, we cause use-after-free.
This shows us that, log tree blocks + bad extent tree can cause wild
dirty pages.
[FIX]
To fix the problem, don't submit any btree write bio if the filesytem
has any error. This is the last safe net, just in case other cleanup
haven't caught catch it.
Link: https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19377
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>
Signed-off-by: David Sterba <dsterba@suse.com>
