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commit 6bf9cd2eed9aee6d742bb9296c994a91f5316949 upstream.
Under somewhat convoluted conditions, it is possible to attempt to
release an extent_buffer that is under io, which triggers a BUG_ON in
btrfs_release_extent_buffer_pages.
This relies on a few different factors. First, extent_buffer reads done
as readahead for searching use WAIT_NONE, so they free the local extent
buffer reference while the io is outstanding. However, they should still
be protected by TREE_REF. However, if the system is doing signficant
reclaim, and simultaneously heavily accessing the extent_buffers, it is
possible for releasepage to race with two concurrent readahead attempts
in a way that leaves TREE_REF unset when the readahead extent buffer is
released.
Essentially, if two tasks race to allocate a new extent_buffer, but the
winner who attempts the first io is rebuffed by a page being locked
(likely by the reclaim itself) then the loser will still go ahead with
issuing the readahead. The loser's call to find_extent_buffer must also
race with the reclaim task reading the extent_buffer's refcount as 1 in
a way that allows the reclaim to re-clear the TREE_REF checked by
find_extent_buffer.
The following represents an example execution demonstrating the race:
CPU0 CPU1 CPU2
reada_for_search reada_for_search
readahead_tree_block readahead_tree_block
find_create_tree_block find_create_tree_block
alloc_extent_buffer alloc_extent_buffer
find_extent_buffer // not found
allocates eb
lock pages
associate pages to eb
insert eb into radix tree
set TREE_REF, refs == 2
unlock pages
read_extent_buffer_pages // WAIT_NONE
not uptodate (brand new eb)
lock_page
if !trylock_page
goto unlock_exit // not an error
free_extent_buffer
release_extent_buffer
atomic_dec_and_test refs to 1
find_extent_buffer // found
try_release_extent_buffer
take refs_lock
reads refs == 1; no io
atomic_inc_not_zero refs to 2
mark_buffer_accessed
check_buffer_tree_ref
// not STALE, won't take refs_lock
refs == 2; TREE_REF set // no action
read_extent_buffer_pages // WAIT_NONE
clear TREE_REF
release_extent_buffer
atomic_dec_and_test refs to 1
unlock_page
still not uptodate (CPU1 read failed on trylock_page)
locks pages
set io_pages > 0
submit io
return
free_extent_buffer
release_extent_buffer
dec refs to 0
delete from radix tree
btrfs_release_extent_buffer_pages
BUG_ON(io_pages > 0)!!!
We observe this at a very low rate in production and were also able to
reproduce it in a test environment by introducing some spurious delays
and by introducing probabilistic trylock_page failures.
To fix it, we apply check_tree_ref at a point where it could not
possibly be unset by a competing task: after io_pages has been
incremented. All the codepaths that clear TREE_REF check for io, so they
would not be able to clear it after this point until the io is done.
Stack trace, for reference:
[1417839.424739] ------------[ cut here ]------------
[1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841!
[1417839.447024] invalid opcode: 0000 [#1] SMP
[1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0
[1417839.517008] Code: ed e9 ...
[1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202
[1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028
[1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0
[1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238
[1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000
[1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90
[1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000
[1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0
[1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[1417839.731320] Call Trace:
[1417839.737103] release_extent_buffer+0x39/0x90
[1417839.746913] read_block_for_search.isra.38+0x2a3/0x370
[1417839.758645] btrfs_search_slot+0x260/0x9b0
[1417839.768054] btrfs_lookup_file_extent+0x4a/0x70
[1417839.778427] btrfs_get_extent+0x15f/0x830
[1417839.787665] ? submit_extent_page+0xc4/0x1c0
[1417839.797474] ? __do_readpage+0x299/0x7a0
[1417839.806515] __do_readpage+0x33b/0x7a0
[1417839.815171] ? btrfs_releasepage+0x70/0x70
[1417839.824597] extent_readpages+0x28f/0x400
[1417839.833836] read_pages+0x6a/0x1c0
[1417839.841729] ? startup_64+0x2/0x30
[1417839.849624] __do_page_cache_readahead+0x13c/0x1a0
[1417839.860590] filemap_fault+0x6c7/0x990
[1417839.869252] ? xas_load+0x8/0x80
[1417839.876756] ? xas_find+0x150/0x190
[1417839.884839] ? filemap_map_pages+0x295/0x3b0
[1417839.894652] __do_fault+0x32/0x110
[1417839.902540] __handle_mm_fault+0xacd/0x1000
[1417839.912156] handle_mm_fault+0xaa/0x1c0
[1417839.921004] __do_page_fault+0x242/0x4b0
[1417839.930044] ? page_fault+0x8/0x30
[1417839.937933] page_fault+0x1e/0x30
[1417839.945631] RIP: 0033:0x33c4bae
[1417839.952927] Code: Bad RIP value.
[1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206
[1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000
[1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
[1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8
[1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79
[1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 432cd2a10f1c10cead91fe706ff5dc52f06d642a ]
When running relocation of a data block group while scrub is running in
parallel, it is possible that the relocation will fail and abort the
current transaction with an -EINVAL error:
[134243.988595] BTRFS info (device sdc): found 14 extents, stage: move data extents
[134243.999871] ------------[ cut here ]------------
[134244.000741] BTRFS: Transaction aborted (error -22)
[134244.001692] WARNING: CPU: 0 PID: 26954 at fs/btrfs/ctree.c:1071 __btrfs_cow_block+0x6a7/0x790 [btrfs]
[134244.003380] Modules linked in: btrfs blake2b_generic xor raid6_pq (...)
[134244.012577] CPU: 0 PID: 26954 Comm: btrfs Tainted: G W 5.6.0-rc7-btrfs-next-58 #5
[134244.014162] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
[134244.016184] RIP: 0010:__btrfs_cow_block+0x6a7/0x790 [btrfs]
[134244.017151] Code: 48 c7 c7 (...)
[134244.020549] RSP: 0018:ffffa41607863888 EFLAGS: 00010286
[134244.021515] RAX: 0000000000000000 RBX: ffff9614bdfe09c8 RCX: 0000000000000000
[134244.022822] RDX: 0000000000000001 RSI: ffffffffb3d63980 RDI: 0000000000000001
[134244.024124] RBP: ffff961589e8c000 R08: 0000000000000000 R09: 0000000000000001
[134244.025424] R10: ffffffffc0ae5955 R11: 0000000000000000 R12: ffff9614bd530d08
[134244.026725] R13: ffff9614ced41b88 R14: ffff9614bdfe2a48 R15: 0000000000000000
[134244.028024] FS: 00007f29b63c08c0(0000) GS:ffff9615ba600000(0000) knlGS:0000000000000000
[134244.029491] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[134244.030560] CR2: 00007f4eb339b000 CR3: 0000000130d6e006 CR4: 00000000003606f0
[134244.031997] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[134244.033153] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[134244.034484] Call Trace:
[134244.034984] btrfs_cow_block+0x12b/0x2b0 [btrfs]
[134244.035859] do_relocation+0x30b/0x790 [btrfs]
[134244.036681] ? do_raw_spin_unlock+0x49/0xc0
[134244.037460] ? _raw_spin_unlock+0x29/0x40
[134244.038235] relocate_tree_blocks+0x37b/0x730 [btrfs]
[134244.039245] relocate_block_group+0x388/0x770 [btrfs]
[134244.040228] btrfs_relocate_block_group+0x161/0x2e0 [btrfs]
[134244.041323] btrfs_relocate_chunk+0x36/0x110 [btrfs]
[134244.041345] btrfs_balance+0xc06/0x1860 [btrfs]
[134244.043382] ? btrfs_ioctl_balance+0x27c/0x310 [btrfs]
[134244.045586] btrfs_ioctl_balance+0x1ed/0x310 [btrfs]
[134244.045611] btrfs_ioctl+0x1880/0x3760 [btrfs]
[134244.049043] ? do_raw_spin_unlock+0x49/0xc0
[134244.049838] ? _raw_spin_unlock+0x29/0x40
[134244.050587] ? __handle_mm_fault+0x11b3/0x14b0
[134244.051417] ? ksys_ioctl+0x92/0xb0
[134244.052070] ksys_ioctl+0x92/0xb0
[134244.052701] ? trace_hardirqs_off_thunk+0x1a/0x1c
[134244.053511] __x64_sys_ioctl+0x16/0x20
[134244.054206] do_syscall_64+0x5c/0x280
[134244.054891] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[134244.055819] RIP: 0033:0x7f29b51c9dd7
[134244.056491] Code: 00 00 00 (...)
[134244.059767] RSP: 002b:00007ffcccc1dd08 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[134244.061168] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f29b51c9dd7
[134244.062474] RDX: 00007ffcccc1dda0 RSI: 00000000c4009420 RDI: 0000000000000003
[134244.063771] RBP: 0000000000000003 R08: 00005565cea4b000 R09: 0000000000000000
[134244.065032] R10: 0000000000000541 R11: 0000000000000202 R12: 00007ffcccc2060a
[134244.066327] R13: 00007ffcccc1dda0 R14: 0000000000000002 R15: 00007ffcccc1dec0
[134244.067626] irq event stamp: 0
[134244.068202] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[134244.069351] hardirqs last disabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
[134244.070909] softirqs last enabled at (0): [<ffffffffb2abdedf>] copy_process+0x74f/0x2020
[134244.072392] softirqs last disabled at (0): [<0000000000000000>] 0x0
[134244.073432] ---[ end trace bd7c03622e0b0a99 ]---
The -EINVAL error comes from the following chain of function calls:
__btrfs_cow_block() <-- aborts the transaction
btrfs_reloc_cow_block()
replace_file_extents()
get_new_location() <-- returns -EINVAL
When relocating a data block group, for each allocated extent of the block
group, we preallocate another extent (at prealloc_file_extent_cluster()),
associated with the data relocation inode, and then dirty all its pages.
These preallocated extents have, and must have, the same size that extents
from the data block group being relocated have.
Later before we start the relocation stage that updates pointers (bytenr
field of file extent items) to point to the the new extents, we trigger
writeback for the data relocation inode. The expectation is that writeback
will write the pages to the previously preallocated extents, that it
follows the NOCOW path. That is generally the case, however, if a scrub
is running it may have turned the block group that contains those extents
into RO mode, in which case writeback falls back to the COW path.
However in the COW path instead of allocating exactly one extent with the
expected size, the allocator may end up allocating several smaller extents
due to free space fragmentation - because we tell it at cow_file_range()
that the minimum allocation size can match the filesystem's sector size.
This later breaks the relocation's expectation that an extent associated
to a file extent item in the data relocation inode has the same size as
the respective extent pointed by a file extent item in another tree - in
this case the extent to which the relocation inode poins to is smaller,
causing relocation.c:get_new_location() to return -EINVAL.
For example, if we are relocating a data block group X that has a logical
address of X and the block group has an extent allocated at the logical
address X + 128KiB with a size of 64KiB:
1) At prealloc_file_extent_cluster() we allocate an extent for the data
relocation inode with a size of 64KiB and associate it to the file
offset 128KiB (X + 128KiB - X) of the data relocation inode. This
preallocated extent was allocated at block group Z;
2) A scrub running in parallel turns block group Z into RO mode and
starts scrubing its extents;
3) Relocation triggers writeback for the data relocation inode;
4) When running delalloc (btrfs_run_delalloc_range()), we try first the
NOCOW path because the data relocation inode has BTRFS_INODE_PREALLOC
set in its flags. However, because block group Z is in RO mode, the
NOCOW path (run_delalloc_nocow()) falls back into the COW path, by
calling cow_file_range();
5) At cow_file_range(), in the first iteration of the while loop we call
btrfs_reserve_extent() to allocate a 64KiB extent and pass it a minimum
allocation size of 4KiB (fs_info->sectorsize). Due to free space
fragmentation, btrfs_reserve_extent() ends up allocating two extents
of 32KiB each, each one on a different iteration of that while loop;
6) Writeback of the data relocation inode completes;
7) Relocation proceeds and ends up at relocation.c:replace_file_extents(),
with a leaf which has a file extent item that points to the data extent
from block group X, that has a logical address (bytenr) of X + 128KiB
and a size of 64KiB. Then it calls get_new_location(), which does a
lookup in the data relocation tree for a file extent item starting at
offset 128KiB (X + 128KiB - X) and belonging to the data relocation
inode. It finds a corresponding file extent item, however that item
points to an extent that has a size of 32KiB, which doesn't match the
expected size of 64KiB, resuling in -EINVAL being returned from this
function and propagated up to __btrfs_cow_block(), which aborts the
current transaction.
To fix this make sure that at cow_file_range() when we call the allocator
we pass it a minimum allocation size corresponding the desired extent size
if the inode belongs to the data relocation tree, otherwise pass it the
filesystem's sector size as the minimum allocation size.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3752d22fcea160cc2493e34f5e0e41cdd7fdd921 ]
This patch deletes local variable disk_num_bytes as its value
is same as num_bytes in the function cow_file_range().
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9fecd13202f520f3f25d5b1c313adb740fe19773 ]
When removing a block group, if we fail to delete the block group's item
from the extent tree, we jump to the 'out' label and end up decrementing
the block group's reference count once only (by 1), resulting in a counter
leak because the block group at that point was already removed from the
block group cache rbtree - so we have to decrement the reference count
twice, once for the rbtree and once for our lookup at the start of the
function.
There is a second bug where if removing the free space tree entries (the
call to remove_block_group_free_space()) fails we end up jumping to the
'out_put_group' label but end up decrementing the reference count only
once, when we should have done it twice, since we have already removed
the block group from the block group cache rbtree. This happens because
the reference count decrement for the rbtree reference happens after
attempting to remove the free space tree entries, which is far away from
the place where we remove the block group from the rbtree.
To make things less error prone, decrement the reference count for the
rbtree immediately after removing the block group from it. This also
eleminates the need for two different exit labels on error, renaming
'out_put_label' to just 'out' and removing the old 'out'.
Fixes: f6033c5e333238 ("btrfs: fix block group leak when removing fails")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 4b1946284dd6641afdb9457101056d9e6ee6204c upstream.
If we attempt to write to prealloc extent located after eof using a
RWF_NOWAIT write, we always fail with -EAGAIN.
We do actually check if we have an allocated extent for the write at
the start of btrfs_file_write_iter() through a call to check_can_nocow(),
but later when we go into the actual direct IO write path we simply
return -EAGAIN if the write starts at or beyond EOF.
Trivial to reproduce:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ touch /mnt/foo
$ chattr +C /mnt/foo
$ xfs_io -d -c "pwrite -S 0xab 0 64K" /mnt/foo
wrote 65536/65536 bytes at offset 0
64 KiB, 16 ops; 0.0004 sec (135.575 MiB/sec and 34707.1584 ops/sec)
$ xfs_io -c "falloc -k 64K 1M" /mnt/foo
$ xfs_io -d -c "pwrite -N -V 1 -S 0xfe -b 64K 64K 64K" /mnt/foo
pwrite: Resource temporarily unavailable
On xfs and ext4 the write succeeds, as expected.
Fix this by removing the wrong check at btrfs_direct_IO().
Fixes: edf064e7c6fec3 ("btrfs: nowait aio support")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit e2c8e92d1140754073ad3799eb6620c76bab2078 ]
If an error happens while running dellaloc in COW mode for a range, we can
end up calling extent_clear_unlock_delalloc() for a range that goes beyond
our range's end offset by 1 byte, which affects 1 extra page. This results
in clearing bits and doing page operations (such as a page unlock) outside
our target range.
Fix that by calling extent_clear_unlock_delalloc() with an inclusive end
offset, instead of an exclusive end offset, at cow_file_range().
Fixes: a315e68f6e8b30 ("Btrfs: fix invalid attempt to free reserved space on failure to cow range")
CC: stable@vger.kernel.org # 4.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 6d3113a193e3385c72240096fe397618ecab6e43 ]
In btrfs_submit_direct_hook(), if a direct I/O write doesn't span a RAID
stripe or chunk, we submit orig_bio without cloning it. In this case, we
don't increment pending_bios. Then, if btrfs_submit_dio_bio() fails, we
decrement pending_bios to -1, and we never complete orig_bio. Fix it by
initializing pending_bios to 1 instead of incrementing later.
Fixing this exposes another bug: we put orig_bio prematurely and then
put it again from end_io. Fix it by not putting orig_bio.
After this change, pending_bios is really more of a reference count, but
I'll leave that cleanup separate to keep the fix small.
Fixes: e65e15355429 ("btrfs: fix panic caused by direct IO")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 89efda52e6b6930f80f5adda9c3c9edfb1397191 upstream.
Whenever a chown is executed, all capabilities of the file being touched
are lost. When doing incremental send with a file with capabilities,
there is a situation where the capability can be lost on the receiving
side. The sequence of actions bellow shows the problem:
$ mount /dev/sda fs1
$ mount /dev/sdb fs2
$ touch fs1/foo.bar
$ setcap cap_sys_nice+ep fs1/foo.bar
$ btrfs subvolume snapshot -r fs1 fs1/snap_init
$ btrfs send fs1/snap_init | btrfs receive fs2
$ chgrp adm fs1/foo.bar
$ setcap cap_sys_nice+ep fs1/foo.bar
$ btrfs subvolume snapshot -r fs1 fs1/snap_complete
$ btrfs subvolume snapshot -r fs1 fs1/snap_incremental
$ btrfs send fs1/snap_complete | btrfs receive fs2
$ btrfs send -p fs1/snap_init fs1/snap_incremental | btrfs receive fs2
At this point, only a chown was emitted by "btrfs send" since only the
group was changed. This makes the cap_sys_nice capability to be dropped
from fs2/snap_incremental/foo.bar
To fix that, only emit capabilities after chown is emitted. The current
code first checks for xattrs that are new/changed, emits them, and later
emit the chown. Now, __process_new_xattr skips capabilities, letting
only finish_inode_if_needed to emit them, if they exist, for the inode
being processed.
This behavior was being worked around in "btrfs receive" side by caching
the capability and only applying it after chown. Now, xattrs are only
emmited _after_ chown, making that workaround not needed anymore.
Link: https://github.com/kdave/btrfs-progs/issues/202
CC: stable@vger.kernel.org # 4.4+
Suggested-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 7e4a3f7ed5d54926ec671bbb13e171cfe179cc50 ]
We are currently treating any non-zero return value from btrfs_next_leaf()
the same way, by going to the code that inserts a new checksum item in the
tree. However if btrfs_next_leaf() returns an error (a value < 0), we
should just stop and return the error, and not behave as if nothing has
happened, since in that case we do not have a way to know if there is a
next leaf or we are currently at the last leaf already.
So fix that by returning the error from btrfs_next_leaf().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit f135cea30de5f74d5bfb5116682073841fb4af8f upstream.
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: 31d11b83b96f ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f6033c5e333238f299c3ae03fac8cc1365b23b77 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4d4225fc228e46948486d8b8207955f0c031b92e upstream.
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: 054570a1dc94 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 351cbf6e4410e7ece05e35d0a07320538f2418b4 ]
Zygo reported the following lockdep splat while testing the balance
patches
======================================================
WARNING: possible circular locking dependency detected
5.6.0-c6f0579d496a+ #53 Not tainted
------------------------------------------------------
kswapd0/1133 is trying to acquire lock:
ffff888092f622c0 (&delayed_node->mutex){+.+.}, at: __btrfs_release_delayed_node+0x7c/0x5b0
but task is already holding lock:
ffffffff8fc5f860 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}:
fs_reclaim_acquire.part.91+0x29/0x30
fs_reclaim_acquire+0x19/0x20
kmem_cache_alloc_trace+0x32/0x740
add_block_entry+0x45/0x260
btrfs_ref_tree_mod+0x6e2/0x8b0
btrfs_alloc_tree_block+0x789/0x880
alloc_tree_block_no_bg_flush+0xc6/0xf0
__btrfs_cow_block+0x270/0x940
btrfs_cow_block+0x1ba/0x3a0
btrfs_search_slot+0x999/0x1030
btrfs_insert_empty_items+0x81/0xe0
btrfs_insert_delayed_items+0x128/0x7d0
__btrfs_run_delayed_items+0xf4/0x2a0
btrfs_run_delayed_items+0x13/0x20
btrfs_commit_transaction+0x5cc/0x1390
insert_balance_item.isra.39+0x6b2/0x6e0
btrfs_balance+0x72d/0x18d0
btrfs_ioctl_balance+0x3de/0x4c0
btrfs_ioctl+0x30ab/0x44a0
ksys_ioctl+0xa1/0xe0
__x64_sys_ioctl+0x43/0x50
do_syscall_64+0x77/0x2c0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (&delayed_node->mutex){+.+.}:
__lock_acquire+0x197e/0x2550
lock_acquire+0x103/0x220
__mutex_lock+0x13d/0xce0
mutex_lock_nested+0x1b/0x20
__btrfs_release_delayed_node+0x7c/0x5b0
btrfs_remove_delayed_node+0x49/0x50
btrfs_evict_inode+0x6fc/0x900
evict+0x19a/0x2c0
dispose_list+0xa0/0xe0
prune_icache_sb+0xbd/0xf0
super_cache_scan+0x1b5/0x250
do_shrink_slab+0x1f6/0x530
shrink_slab+0x32e/0x410
shrink_node+0x2a5/0xba0
balance_pgdat+0x4bd/0x8a0
kswapd+0x35a/0x800
kthread+0x1e9/0x210
ret_from_fork+0x3a/0x50
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&delayed_node->mutex);
lock(fs_reclaim);
lock(&delayed_node->mutex);
*** DEADLOCK ***
3 locks held by kswapd0/1133:
#0: ffffffff8fc5f860 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
#1: ffffffff8fc380d8 (shrinker_rwsem){++++}, at: shrink_slab+0x1e8/0x410
#2: ffff8881e0e6c0e8 (&type->s_umount_key#42){++++}, at: trylock_super+0x1b/0x70
stack backtrace:
CPU: 2 PID: 1133 Comm: kswapd0 Not tainted 5.6.0-c6f0579d496a+ #53
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
dump_stack+0xc1/0x11a
print_circular_bug.isra.38.cold.57+0x145/0x14a
check_noncircular+0x2a9/0x2f0
? print_circular_bug.isra.38+0x130/0x130
? stack_trace_consume_entry+0x90/0x90
? save_trace+0x3cc/0x420
__lock_acquire+0x197e/0x2550
? btrfs_inode_clear_file_extent_range+0x9b/0xb0
? register_lock_class+0x960/0x960
lock_acquire+0x103/0x220
? __btrfs_release_delayed_node+0x7c/0x5b0
__mutex_lock+0x13d/0xce0
? __btrfs_release_delayed_node+0x7c/0x5b0
? __asan_loadN+0xf/0x20
? pvclock_clocksource_read+0xeb/0x190
? __btrfs_release_delayed_node+0x7c/0x5b0
? mutex_lock_io_nested+0xc20/0xc20
? __kasan_check_read+0x11/0x20
? check_chain_key+0x1e6/0x2e0
mutex_lock_nested+0x1b/0x20
? mutex_lock_nested+0x1b/0x20
__btrfs_release_delayed_node+0x7c/0x5b0
btrfs_remove_delayed_node+0x49/0x50
btrfs_evict_inode+0x6fc/0x900
? btrfs_setattr+0x840/0x840
? do_raw_spin_unlock+0xa8/0x140
evict+0x19a/0x2c0
dispose_list+0xa0/0xe0
prune_icache_sb+0xbd/0xf0
? invalidate_inodes+0x310/0x310
super_cache_scan+0x1b5/0x250
do_shrink_slab+0x1f6/0x530
shrink_slab+0x32e/0x410
? do_shrink_slab+0x530/0x530
? do_shrink_slab+0x530/0x530
? __kasan_check_read+0x11/0x20
? mem_cgroup_protected+0x13d/0x260
shrink_node+0x2a5/0xba0
balance_pgdat+0x4bd/0x8a0
? mem_cgroup_shrink_node+0x490/0x490
? _raw_spin_unlock_irq+0x27/0x40
? finish_task_switch+0xce/0x390
? rcu_read_lock_bh_held+0xb0/0xb0
kswapd+0x35a/0x800
? _raw_spin_unlock_irqrestore+0x4c/0x60
? balance_pgdat+0x8a0/0x8a0
? finish_wait+0x110/0x110
? __kasan_check_read+0x11/0x20
? __kthread_parkme+0xc6/0xe0
? balance_pgdat+0x8a0/0x8a0
kthread+0x1e9/0x210
? kthread_create_worker_on_cpu+0xc0/0xc0
ret_from_fork+0x3a/0x50
This is because we hold that delayed node's mutex while doing tree
operations. Fix this by just wrapping the searches in nofs.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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|
[ Upstream commit f0cc2cd70164efe8f75c5d99560f0f69969c72e4 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
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commit 8e19c9732ad1d127b5575a10f4fbcacf740500ff upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
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[ Upstream commit ea287ab157c2816bf12aad4cece41372f9d146b4 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 7b7b74315b24dc064bc1c683659061c3d48f8668 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
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commit e75fd33b3f744f644061a4f9662bd63f5434f806 upstream.
In btrfs_wait_ordered_range() once we find an ordered extent that has
finished with an error we exit the loop and don't wait for any other
ordered extents that might be still in progress.
All the users of btrfs_wait_ordered_range() expect that there are no more
ordered extents in progress after that function returns. So past fixes
such like the ones from the two following commits:
ff612ba7849964 ("btrfs: fix panic during relocation after ENOSPC before
writeback happens")
28aeeac1dd3080 ("Btrfs: fix panic when starting bg cache writeout after
IO error")
don't work when there are multiple ordered extents in the range.
Fix that by making btrfs_wait_ordered_range() wait for all ordered extents
even after it finds one that had an error.
Link: https://github.com/kdave/btrfs-progs/issues/228#issuecomment-569777554
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 1e90315149f3fe148e114a5de86f0196d1c21fa5 upstream.
btrfs_assert_delayed_root_empty() will check if the delayed root is
completely empty, but this is a filesystem-wide check. On cleanup we
may have allowed other transactions to begin, for whatever reason, and
thus the delayed root is not empty.
So remove this check from cleanup_one_transation(). This however can
stay in btrfs_cleanup_transaction(), because it checks only after all of
the transactions have been properly cleaned up, and thus is valid.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b778cf962d71a0e737923d55d0432f3bd287258e upstream.
I hit the following warning while running my error injection stress
testing:
WARNING: CPU: 3 PID: 1453 at fs/btrfs/space-info.h:108 btrfs_free_reserved_data_space_noquota+0xfd/0x160 [btrfs]
RIP: 0010:btrfs_free_reserved_data_space_noquota+0xfd/0x160 [btrfs]
Call Trace:
btrfs_free_reserved_data_space+0x4f/0x70 [btrfs]
__btrfs_prealloc_file_range+0x378/0x470 [btrfs]
elfcorehdr_read+0x40/0x40
? elfcorehdr_read+0x40/0x40
? btrfs_commit_transaction+0xca/0xa50 [btrfs]
? dput+0xb4/0x2a0
? btrfs_log_dentry_safe+0x55/0x70 [btrfs]
? btrfs_sync_file+0x30e/0x420 [btrfs]
? do_fsync+0x38/0x70
? __x64_sys_fdatasync+0x13/0x20
? do_syscall_64+0x5b/0x1b0
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
This happens if we fail to insert our reserved file extent. At this
point we've already converted our reservation from ->bytes_may_use to
->bytes_reserved. However once we break we will attempt to free
everything from [cur_offset, end] from ->bytes_may_use, but our extent
reservation will overlap part of this.
Fix this problem by adding ins.offset (our extent allocation size) to
cur_offset so we remove the actual remaining part from ->bytes_may_use.
I validated this fix using my inject-error.py script
python inject-error.py -o should_fail_bio -t cache_save_setup -t \
__btrfs_prealloc_file_range \
-t insert_reserved_file_extent.constprop.0 \
-r "-5" ./run-fsstress.sh
where run-fsstress.sh simply mounts and runs fsstress on a disk.
CC: stable@vger.kernel.org # 4.4+
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit a69976bc69308aa475d0ba3b8b3efd1d013c0460 ]
We had a report indicating that some read errors aren't reported by the
device stats in the userland. It is important to have the errors
reported in the device stat as user land scripts might depend on it to
take the reasonable corrective actions. But to debug these issue we need
to be really sure that request to reset the device stat did not come
from the userland itself. So log an info message when device error reset
happens.
For example:
BTRFS info (device sdc): device stats zeroed by btrfs(9223)
Reported-by: philip@philip-seeger.de
Link: https://www.spinics.net/lists/linux-btrfs/msg96528.html
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 4babad10198fa73fe73239d02c2e99e3333f5f5c ]
Dan's smatch tool reports
fs/btrfs/file-item.c:295 btrfs_lookup_bio_sums()
warn: should this be 'count == -1'
which points to the while (count--) loop. With count == 0 the check
itself could decrement it to -1. There's a WARN_ON a few lines below
that has never been seen in practice though.
It turns out that the value of page_bytes_left matches the count (by
sectorsize multiples). The loop never reaches the state where count
would go to -1, because page_bytes_left == 0 is found first and this
breaks out.
For clarity, use only plain check on count (and only for positive
value), decrement safely inside the loop. Any other discrepancy after
the whole bio list processing should be reported by the exising
WARN_ON_ONCE as well.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 3dbd351df42109902fbcebf27104149226a4fcd9 ]
A user reports a possible NULL-pointer dereference in
btrfsic_process_superblock(). We are assigning state->fs_info to a local
fs_info variable and afterwards checking for the presence of state.
While we would BUG_ON() a NULL state anyways, we can also just remove
the local fs_info copy, as fs_info is only used once as the first
argument for btrfs_num_copies(). There we can just pass in
state->fs_info as well.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205003
Signed-off-by: Johannes Thumshirn <jth@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 10a3a3edc5b89a8cd095bc63495fb1e0f42047d9 upstream.
A remount to a read-write filesystem is not safe when there's tree-log
to be replayed. Files that could be opened until now might be affected
by the changes in the tree-log.
A regular mount is needed to replay the log so the filesystem presents
the consistent view with the pending changes included.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e8294f2f6aa6208ed0923aa6d70cea3be178309a upstream.
There's no logged information about tree-log replay although this is
something that points to previous unclean unmount. Other filesystems
report that as well.
Suggested-by: Chris Murphy <lists@colorremedies.com>
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ac05ca913e9f3871126d61da275bfe8516ff01ca upstream.
We have a few cases where we allow an extent map that is in an extent map
tree to be merged with other extents in the tree. Such cases include the
unpinning of an extent after the respective ordered extent completed or
after logging an extent during a fast fsync. This can lead to subtle and
dangerous problems because when doing the merge some other task might be
using the same extent map and as consequence see an inconsistent state of
the extent map - for example sees the new length but has seen the old start
offset.
With luck this triggers a BUG_ON(), and not some silent bug, such as the
following one in __do_readpage():
$ cat -n fs/btrfs/extent_io.c
3061 static int __do_readpage(struct extent_io_tree *tree,
3062 struct page *page,
(...)
3127 em = __get_extent_map(inode, page, pg_offset, cur,
3128 end - cur + 1, get_extent, em_cached);
3129 if (IS_ERR_OR_NULL(em)) {
3130 SetPageError(page);
3131 unlock_extent(tree, cur, end);
3132 break;
3133 }
3134 extent_offset = cur - em->start;
3135 BUG_ON(extent_map_end(em) <= cur);
(...)
Consider the following example scenario, where we end up hitting the
BUG_ON() in __do_readpage().
We have an inode with a size of 8KiB and 2 extent maps:
extent A: file offset 0, length 4KiB, disk_bytenr = X, persisted on disk by
a previous transaction
extent B: file offset 4KiB, length 4KiB, disk_bytenr = X + 4KiB, not yet
persisted but writeback started for it already. The extent map
is pinned since there's writeback and an ordered extent in
progress, so it can not be merged with extent map A yet
The following sequence of steps leads to the BUG_ON():
1) The ordered extent for extent B completes, the respective page gets its
writeback bit cleared and the extent map is unpinned, at that point it
is not yet merged with extent map A because it's in the list of modified
extents;
2) Due to memory pressure, or some other reason, the MM subsystem releases
the page corresponding to extent B - btrfs_releasepage() is called and
returns 1, meaning the page can be released as it's not dirty, not under
writeback anymore and the extent range is not locked in the inode's
iotree. However the extent map is not released, either because we are
not in a context that allows memory allocations to block or because the
inode's size is smaller than 16MiB - in this case our inode has a size
of 8KiB;
3) Task B needs to read extent B and ends up __do_readpage() through the
btrfs_readpage() callback. At __do_readpage() it gets a reference to
extent map B;
4) Task A, doing a fast fsync, calls clear_em_loggin() against extent map B
while holding the write lock on the inode's extent map tree - this
results in try_merge_map() being called and since it's possible to merge
extent map B with extent map A now (the extent map B was removed from
the list of modified extents), the merging begins - it sets extent map
B's start offset to 0 (was 4KiB), but before it increments the map's
length to 8KiB (4kb + 4KiB), task A is at:
BUG_ON(extent_map_end(em) <= cur);
The call to extent_map_end() sees the extent map has a start of 0
and a length still at 4KiB, so it returns 4KiB and 'cur' is 4KiB, so
the BUG_ON() is triggered.
So it's dangerous to modify an extent map that is in the tree, because some
other task might have got a reference to it before and still using it, and
needs to see a consistent map while using it. Generally this is very rare
since most paths that lookup and use extent maps also have the file range
locked in the inode's iotree. The fsync path is pretty much the only
exception where we don't do it to avoid serialization with concurrent
reads.
Fix this by not allowing an extent map do be merged if if it's being used
by tasks other then the one attempting to merge the extent map (when the
reference count of the extent map is greater than 2).
Reported-by: ryusuke1925 <st13s20@gm.ibaraki-ct.ac.jp>
Reported-by: Koki Mitani <koki.mitani.xg@hco.ntt.co.jp>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=206211
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 42ffb0bf584ae5b6b38f72259af1e0ee417ac77f ]
There exists a deadlock with range_cyclic that has existed forever. If
we loop around with a bio already built we could deadlock with a writer
who has the page locked that we're attempting to write but is waiting on
a page in our bio to be written out. The task traces are as follows
PID: 1329874 TASK: ffff889ebcdf3800 CPU: 33 COMMAND: "kworker/u113:5"
#0 [ffffc900297bb658] __schedule at ffffffff81a4c33f
#1 [ffffc900297bb6e0] schedule at ffffffff81a4c6e3
#2 [ffffc900297bb6f8] io_schedule at ffffffff81a4ca42
#3 [ffffc900297bb708] __lock_page at ffffffff811f145b
#4 [ffffc900297bb798] __process_pages_contig at ffffffff814bc502
#5 [ffffc900297bb8c8] lock_delalloc_pages at ffffffff814bc684
#6 [ffffc900297bb900] find_lock_delalloc_range at ffffffff814be9ff
#7 [ffffc900297bb9a0] writepage_delalloc at ffffffff814bebd0
#8 [ffffc900297bba18] __extent_writepage at ffffffff814bfbf2
#9 [ffffc900297bba98] extent_write_cache_pages at ffffffff814bffbd
PID: 2167901 TASK: ffff889dc6a59c00 CPU: 14 COMMAND:
"aio-dio-invalid"
#0 [ffffc9003b50bb18] __schedule at ffffffff81a4c33f
#1 [ffffc9003b50bba0] schedule at ffffffff81a4c6e3
#2 [ffffc9003b50bbb8] io_schedule at ffffffff81a4ca42
#3 [ffffc9003b50bbc8] wait_on_page_bit at ffffffff811f24d6
#4 [ffffc9003b50bc60] prepare_pages at ffffffff814b05a7
#5 [ffffc9003b50bcd8] btrfs_buffered_write at ffffffff814b1359
#6 [ffffc9003b50bdb0] btrfs_file_write_iter at ffffffff814b5933
#7 [ffffc9003b50be38] new_sync_write at ffffffff8128f6a8
#8 [ffffc9003b50bec8] vfs_write at ffffffff81292b9d
#9 [ffffc9003b50bf00] ksys_pwrite64 at ffffffff81293032
I used drgn to find the respective pages we were stuck on
page_entry.page 0xffffea00fbfc7500 index 8148 bit 15 pid 2167901
page_entry.page 0xffffea00f9bb7400 index 7680 bit 0 pid 1329874
As you can see the kworker is waiting for bit 0 (PG_locked) on index
7680, and aio-dio-invalid is waiting for bit 15 (PG_writeback) on index
8148. aio-dio-invalid has 7680, and the kworker epd looks like the
following
crash> struct extent_page_data ffffc900297bbbb0
struct extent_page_data {
bio = 0xffff889f747ed830,
tree = 0xffff889eed6ba448,
extent_locked = 0,
sync_io = 0
}
Probably worth mentioning as well that it waits for writeback of the
page to complete while holding a lock on it (at prepare_pages()).
Using drgn I walked the bio pages looking for page
0xffffea00fbfc7500 which is the one we're waiting for writeback on
bio = Object(prog, 'struct bio', address=0xffff889f747ed830)
for i in range(0, bio.bi_vcnt.value_()):
bv = bio.bi_io_vec[i]
if bv.bv_page.value_() == 0xffffea00fbfc7500:
print("FOUND IT")
which validated what I suspected.
The fix for this is simple, flush the epd before we loop back around to
the beginning of the file during writeout.
Fixes: b293f02e1423 ("Btrfs: Add writepages support")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7227ff4de55d931bbdc156c8ef0ce4f100c78a5b ]
There is a race between adding and removing elements to the tree mod log
list and rbtree that can lead to use-after-free problems.
Consider the following example that explains how/why the problems happens:
1) Task A has mod log element with sequence number 200. It currently is
the only element in the mod log list;
2) Task A calls btrfs_put_tree_mod_seq() because it no longer needs to
access the tree mod log. When it enters the function, it initializes
'min_seq' to (u64)-1. Then it acquires the lock 'tree_mod_seq_lock'
before checking if there are other elements in the mod seq list.
Since the list it empty, 'min_seq' remains set to (u64)-1. Then it
unlocks the lock 'tree_mod_seq_lock';
3) Before task A acquires the lock 'tree_mod_log_lock', task B adds
itself to the mod seq list through btrfs_get_tree_mod_seq() and gets a
sequence number of 201;
4) Some other task, name it task C, modifies a btree and because there
elements in the mod seq list, it adds a tree mod elem to the tree
mod log rbtree. That node added to the mod log rbtree is assigned
a sequence number of 202;
5) Task B, which is doing fiemap and resolving indirect back references,
calls btrfs get_old_root(), with 'time_seq' == 201, which in turn
calls tree_mod_log_search() - the search returns the mod log node
from the rbtree with sequence number 202, created by task C;
6) Task A now acquires the lock 'tree_mod_log_lock', starts iterating
the mod log rbtree and finds the node with sequence number 202. Since
202 is less than the previously computed 'min_seq', (u64)-1, it
removes the node and frees it;
7) Task B still has a pointer to the node with sequence number 202, and
it dereferences the pointer itself and through the call to
__tree_mod_log_rewind(), resulting in a use-after-free problem.
This issue can be triggered sporadically with the test case generic/561
from fstests, and it happens more frequently with a higher number of
duperemove processes. When it happens to me, it either freezes the VM or
it produces a trace like the following before crashing:
[ 1245.321140] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[ 1245.321200] CPU: 1 PID: 26997 Comm: pool Not tainted 5.5.0-rc6-btrfs-next-52 #1
[ 1245.321235] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[ 1245.321287] RIP: 0010:rb_next+0x16/0x50
[ 1245.321307] Code: ....
[ 1245.321372] RSP: 0018:ffffa151c4d039b0 EFLAGS: 00010202
[ 1245.321388] RAX: 6b6b6b6b6b6b6b6b RBX: ffff8ae221363c80 RCX: 6b6b6b6b6b6b6b6b
[ 1245.321409] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8ae221363c80
[ 1245.321439] RBP: ffff8ae20fcc4688 R08: 0000000000000002 R09: 0000000000000000
[ 1245.321475] R10: ffff8ae20b120910 R11: 00000000243f8bb1 R12: 0000000000000038
[ 1245.321506] R13: ffff8ae221363c80 R14: 000000000000075f R15: ffff8ae223f762b8
[ 1245.321539] FS: 00007fdee1ec7700(0000) GS:ffff8ae236c80000(0000) knlGS:0000000000000000
[ 1245.321591] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1245.321614] CR2: 00007fded4030c48 CR3: 000000021da16003 CR4: 00000000003606e0
[ 1245.321642] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1245.321668] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1245.321706] Call Trace:
[ 1245.321798] __tree_mod_log_rewind+0xbf/0x280 [btrfs]
[ 1245.321841] btrfs_search_old_slot+0x105/0xd00 [btrfs]
[ 1245.321877] resolve_indirect_refs+0x1eb/0xc60 [btrfs]
[ 1245.321912] find_parent_nodes+0x3dc/0x11b0 [btrfs]
[ 1245.321947] btrfs_check_shared+0x115/0x1c0 [btrfs]
[ 1245.321980] ? extent_fiemap+0x59d/0x6d0 [btrfs]
[ 1245.322029] extent_fiemap+0x59d/0x6d0 [btrfs]
[ 1245.322066] do_vfs_ioctl+0x45a/0x750
[ 1245.322081] ksys_ioctl+0x70/0x80
[ 1245.322092] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 1245.322113] __x64_sys_ioctl+0x16/0x20
[ 1245.322126] do_syscall_64+0x5c/0x280
[ 1245.322139] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1245.322155] RIP: 0033:0x7fdee3942dd7
[ 1245.322177] Code: ....
[ 1245.322258] RSP: 002b:00007fdee1ec6c88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 1245.322294] RAX: ffffffffffffffda RBX: 00007fded40210d8 RCX: 00007fdee3942dd7
[ 1245.322314] RDX: 00007fded40210d8 RSI: 00000000c020660b RDI: 0000000000000004
[ 1245.322337] RBP: 0000562aa89e7510 R08: 0000000000000000 R09: 00007fdee1ec6d44
[ 1245.322369] R10: 0000000000000073 R11: 0000000000000246 R12: 00007fdee1ec6d48
[ 1245.322390] R13: 00007fdee1ec6d40 R14: 00007fded40210d0 R15: 00007fdee1ec6d50
[ 1245.322423] Modules linked in: ....
[ 1245.323443] ---[ end trace 01de1e9ec5dff3cd ]---
Fix this by ensuring that btrfs_put_tree_mod_seq() computes the minimum
sequence number and iterates the rbtree while holding the lock
'tree_mod_log_lock' in write mode. Also get rid of the 'tree_mod_seq_lock'
lock, since it is now redundant.
Fixes: bd989ba359f2ac ("Btrfs: add tree modification log functions")
Fixes: 097b8a7c9e48e2 ("Btrfs: join tree mod log code with the code holding back delayed refs")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b1a09f1ec540408abf3a50d15dff5d9506932693 ]
The wrappers are trivial and do not bring any extra value on top of the
plain locking primitives.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 4e19443da1941050b346f8fc4c368aa68413bc88 ]
Sometimes when running generic/475 we would trip the
WARN_ON(cache->reserved) check when free'ing the block groups on umount.
This is because sometimes we don't commit the transaction because of IO
errors and thus do not cleanup the tree logs until at umount time.
These blocks are still reserved until they are cleaned up, but they
aren't cleaned up until _after_ we do the free block groups work. Fix
this by moving the free after free'ing the fs roots, that way all of the
tree logs are cleaned up and we have a properly cleaned fs. A bunch of
loops of generic/475 confirmed this fixes the problem.
CC: stable@vger.kernel.org # 4.9+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 4273eaff9b8d5e141113a5bdf9628c02acf3afe5 ]
We don't need int argument bool shall do in free_root_pointers(). And
rename the argument as it confused two people.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0e56315ca147b3e60c7bf240233a301d3c7fb508 ]
When using the NO_HOLES feature, if we punch a hole into a file and then
fsync it, there are cases where a subsequent fsync will miss the fact that
a hole was punched, resulting in the holes not existing after replaying
the log tree.
Essentially these cases all imply that, tree-log.c:copy_items(), is not
invoked for the leafs that delimit holes, because nothing changed those
leafs in the current transaction. And it's precisely copy_items() where
we currenly detect and log holes, which works as long as the holes are
between file extent items in the input leaf or between the beginning of
input leaf and the previous leaf or between the last item in the leaf
and the next leaf.
First example where we miss a hole:
*) The extent items of the inode span multiple leafs;
*) The punched hole covers a range that affects only the extent items of
the first leaf;
*) The fsync operation is done in full mode (BTRFS_INODE_NEEDS_FULL_SYNC
is set in the inode's runtime flags).
That results in the hole not existing after replaying the log tree.
For example, if the fs/subvolume tree has the following layout for a
particular inode:
Leaf N, generation 10:
[ ... INODE_ITEM INODE_REF EXTENT_ITEM (0 64K) EXTENT_ITEM (64K 128K) ]
Leaf N + 1, generation 10:
[ EXTENT_ITEM (128K 64K) ... ]
If at transaction 11 we punch a hole coverting the range [0, 128K[, we end
up dropping the two extent items from leaf N, but we don't touch the other
leaf, so we end up in the following state:
Leaf N, generation 11:
[ ... INODE_ITEM INODE_REF ]
Leaf N + 1, generation 10:
[ EXTENT_ITEM (128K 64K) ... ]
A full fsync after punching the hole will only process leaf N because it
was modified in the current transaction, but not leaf N + 1, since it
was not modified in the current transaction (generation 10 and not 11).
As a result the fsync will not log any holes, because it didn't process
any leaf with extent items.
Second example where we will miss a hole:
*) An inode as its items spanning 5 (or more) leafs;
*) A hole is punched and it covers only the extents items of the 3rd
leaf. This resulsts in deleting the entire leaf and not touching any
of the other leafs.
So the only leaf that is modified in the current transaction, when
punching the hole, is the first leaf, which contains the inode item.
During the full fsync, the only leaf that is passed to copy_items()
is that first leaf, and that's not enough for the hole detection
code in copy_items() to determine there's a hole between the last
file extent item in the 2nd leaf and the first file extent item in
the 3rd leaf (which was the 4th leaf before punching the hole).
Fix this by scanning all leafs and punch holes as necessary when doing a
full fsync (less common than a non-full fsync) when the NO_HOLES feature
is enabled. The lack of explicit file extent items to mark holes makes it
necessary to scan existing extents to determine if holes exist.
A test case for fstests follows soon.
Fixes: 16e7549f045d33 ("Btrfs: incompatible format change to remove hole extents")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 0ccc3876e4b2a1559a4dbe3126dda4459d38a83b ]
Back in commit a89ca6f24ffe4 ("Btrfs: fix fsync after truncate when
no_holes feature is enabled") I added an assertion that is triggered when
an inline extent is found to assert that the length of the (uncompressed)
data the extent represents is the same as the i_size of the inode, since
that is true most of the time I couldn't find or didn't remembered about
any exception at that time. Later on the assertion was expanded twice to
deal with a case of a compressed inline extent representing a range that
matches the sector size followed by an expanding truncate, and another
case where fallocate can update the i_size of the inode without adding
or updating existing extents (if the fallocate range falls entirely within
the first block of the file). These two expansion/fixes of the assertion
were done by commit 7ed586d0a8241 ("Btrfs: fix assertion on fsync of
regular file when using no-holes feature") and commit 6399fb5a0b69a
("Btrfs: fix assertion failure during fsync in no-holes mode").
These however missed the case where an falloc expands the i_size of an
inode to exactly the sector size and inline extent exists, for example:
$ mkfs.btrfs -f -O no-holes /dev/sdc
$ mount /dev/sdc /mnt
$ xfs_io -f -c "pwrite -S 0xab 0 1096" /mnt/foobar
wrote 1096/1096 bytes at offset 0
1 KiB, 1 ops; 0.0002 sec (4.448 MiB/sec and 4255.3191 ops/sec)
$ xfs_io -c "falloc 1096 3000" /mnt/foobar
$ xfs_io -c "fsync" /mnt/foobar
Segmentation fault
$ dmesg
[701253.602385] assertion failed: len == i_size || (len == fs_info->sectorsize && btrfs_file_extent_compression(leaf, extent) != BTRFS_COMPRESS_NONE) || (len < i_size && i_size < fs_info->sectorsize), file: fs/btrfs/tree-log.c, line: 4727
[701253.602962] ------------[ cut here ]------------
[701253.603224] kernel BUG at fs/btrfs/ctree.h:3533!
[701253.603503] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[701253.603774] CPU: 2 PID: 7192 Comm: xfs_io Tainted: G W 5.0.0-rc8-btrfs-next-45 #1
[701253.604054] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[701253.604650] RIP: 0010:assfail.constprop.23+0x18/0x1a [btrfs]
(...)
[701253.605591] RSP: 0018:ffffbb48c186bc48 EFLAGS: 00010286
[701253.605914] RAX: 00000000000000de RBX: ffff921d0a7afc08 RCX: 0000000000000000
[701253.606244] RDX: 0000000000000000 RSI: ffff921d36b16868 RDI: ffff921d36b16868
[701253.606580] RBP: ffffbb48c186bcf0 R08: 0000000000000000 R09: 0000000000000000
[701253.606913] R10: 0000000000000003 R11: 0000000000000000 R12: ffff921d05d2de18
[701253.607247] R13: ffff921d03b54000 R14: 0000000000000448 R15: ffff921d059ecf80
[701253.607769] FS: 00007f14da906700(0000) GS:ffff921d36b00000(0000) knlGS:0000000000000000
[701253.608163] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[701253.608516] CR2: 000056087ea9f278 CR3: 00000002268e8001 CR4: 00000000003606e0
[701253.608880] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[701253.609250] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[701253.609608] Call Trace:
[701253.609994] btrfs_log_inode+0xdfb/0xe40 [btrfs]
[701253.610383] btrfs_log_inode_parent+0x2be/0xa60 [btrfs]
[701253.610770] ? do_raw_spin_unlock+0x49/0xc0
[701253.611150] btrfs_log_dentry_safe+0x4a/0x70 [btrfs]
[701253.611537] btrfs_sync_file+0x3b2/0x440 [btrfs]
[701253.612010] ? do_sysinfo+0xb0/0xf0
[701253.612552] do_fsync+0x38/0x60
[701253.612988] __x64_sys_fsync+0x10/0x20
[701253.613360] do_syscall_64+0x60/0x1b0
[701253.613733] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[701253.614103] RIP: 0033:0x7f14da4e66d0
(...)
[701253.615250] RSP: 002b:00007fffa670fdb8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
[701253.615647] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f14da4e66d0
[701253.616047] RDX: 000056087ea9c260 RSI: 000056087ea9c260 RDI: 0000000000000003
[701253.616450] RBP: 0000000000000001 R08: 0000000000000020 R09: 0000000000000010
[701253.616854] R10: 000000000000009b R11: 0000000000000246 R12: 000056087ea9c260
[701253.617257] R13: 000056087ea9c240 R14: 0000000000000000 R15: 000056087ea9dd10
(...)
[701253.619941] ---[ end trace e088d74f132b6da5 ]---
Updating the assertion again to allow for this particular case would result
in a meaningless assertion, plus there is currently no risk of logging
content that would result in any corruption after a log replay if the size
of the data encoded in an inline extent is greater than the inode's i_size
(which is not currently possibe either with or without compression),
therefore just remove the assertion.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit e41ca5897489b1c18af75ff0cc8f5c80260b3281 ]
We used to call btrfs_file_extent_inline_len() to get the uncompressed
data size of an inlined extent.
However this function is hiding evil, for compressed extent, it has no
choice but to directly read out ram_bytes from btrfs_file_extent_item.
While for uncompressed extent, it uses item size to calculate the real
data size, and ignoring ram_bytes completely.
In fact, for corrupted ram_bytes, due to above behavior kernel
btrfs_print_leaf() can't even print correct ram_bytes to expose the bug.
Since we have the tree-checker to verify all EXTENT_DATA, such mismatch
can be detected pretty easily, thus we can trust ram_bytes without the
evil btrfs_file_extent_inline_len().
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
commit d62b23c94952e78211a383b7d90ef0afbd9a3717 upstream.
If we abort a transaction we have the following sequence
if (!trans->dirty && list_empty(&trans->new_bgs))
return;
WRITE_ONCE(trans->transaction->aborted, err);
The idea being if we didn't modify anything with our trans handle then
we don't really need to abort the whole transaction, maybe the other
trans handles are fine and we can carry on.
However in the case of create_snapshot we add a pending_snapshot object
to our transaction and then commit the transaction. We don't actually
modify anything. sync() behaves the same way, attach to an existing
transaction and commit it. This means that if we have an IO error in
the right places we could abort the committing transaction with our
trans->dirty being not set and thus not set transaction->aborted.
This is a problem because in the create_snapshot() case we depend on
pending->error being set to something, or btrfs_commit_transaction
returning an error.
If we are not the trans handle that gets to commit the transaction, and
we're waiting on the commit to happen we get our return value from
cur_trans->aborted. If this was not set to anything because sync() hit
an error in the transaction commit before it could modify anything then
cur_trans->aborted would be 0. Thus we'd return 0 from
btrfs_commit_transaction() in create_snapshot.
This is a problem because we then try to do things with
pending_snapshot->snap, which will be NULL because we didn't create the
snapshot, and then we'll get a NULL pointer dereference like the
following
"BUG: kernel NULL pointer dereference, address: 00000000000001f0"
RIP: 0010:btrfs_orphan_cleanup+0x2d/0x330
Call Trace:
? btrfs_mksubvol.isra.31+0x3f2/0x510
btrfs_mksubvol.isra.31+0x4bc/0x510
? __sb_start_write+0xfa/0x200
? mnt_want_write_file+0x24/0x50
btrfs_ioctl_snap_create_transid+0x16c/0x1a0
btrfs_ioctl_snap_create_v2+0x11e/0x1a0
btrfs_ioctl+0x1534/0x2c10
? free_debug_processing+0x262/0x2a3
do_vfs_ioctl+0xa6/0x6b0
? do_sys_open+0x188/0x220
? syscall_trace_enter+0x1f8/0x330
ksys_ioctl+0x60/0x90
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x4a/0x1b0
In order to fix this we need to make sure anybody who calls
commit_transaction has trans->dirty set so that they properly set the
trans->transaction->aborted value properly so any waiters know bad
things happened.
This was found while I was running generic/475 with my modified
fsstress, it reproduced within a few runs. I ran with this patch all
night and didn't see the problem again.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d55966c4279bfc6a0cf0b32bf13f5df228a1eeb6 upstream.
There was some logic added a while ago to clear out f_bavail in statfs()
if we did not have enough free metadata space to satisfy our global
reserve. This was incorrect at the time, however didn't really pose a
problem for normal file systems because we would often allocate chunks
if we got this low on free metadata space, and thus wouldn't really hit
this case unless we were actually full.
Fast forward to today and now we are much better about not allocating
metadata chunks all of the time. Couple this with d792b0f19711 ("btrfs:
always reserve our entire size for the global reserve") which now means
we'll easily have a larger global reserve than our free space, we are
now more likely to trip over this while still having plenty of space.
Fix this by skipping this logic if the global rsv's space_info is not
full. space_info->full is 0 unless we've attempted to allocate a chunk
for that space_info and that has failed. If this happens then the space
for the global reserve is definitely sacred and we need to report
b_avail == 0, but before then we can just use our calculated b_avail.
Reported-by: Martin Steigerwald <martin@lichtvoll.de>
Fixes: ca8a51b3a979 ("btrfs: statfs: report zero available if metadata are exhausted")
CC: stable@vger.kernel.org # 4.5+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Tested-By: Martin Steigerwald <martin@lichtvoll.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[ Upstream commit c09767a8960ca0500fb636bf73686723337debf4 ]
generic_write_checks() may modify iov_iter_count(), so we must get the
count after the call, not before. Using the wrong one has a couple of
consequences:
1. We check a longer range in check_can_nocow() for nowait than we're
actually writing.
2. We create extra hole extent maps in btrfs_cont_expand(). As far as I
can tell, this is harmless, but I might be missing something.
These issues are pretty minor, but let's fix it before something more
important trips on it.
Fixes: edf064e7c6fe ("btrfs: nowait aio support")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 9d123a35d7e97bb2139747b16127c9b22b6a593e ]
If the caching thread fails to allocate a path, it returns without waking
up any cache waiters, leaving them hang forever. Fix this by following the
same approach as when we fail to start the caching thread: print an error
message, disable inode caching and make the wakers fallback to non-caching
mode behaviour (calling btrfs_find_free_objectid()).
Fixes: 581bb050941b4f ("Btrfs: Cache free inode numbers in memory")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit a68ebe0790fc88b4314d17984a2cf99ce2361901 ]
If we fail to start the inode caching thread, we print an error message
and disable the inode cache, however we never wake up any waiters, so they
hang forever waiting for the caching to finish. Fix this by waking them
up and have them fallback to a call to btrfs_find_free_objectid().
Fixes: e60efa84252c05 ("Btrfs: avoid triggering bug_on() when we fail to start inode caching task")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
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[ Upstream commit 7764d56baa844d7f6206394f21a0e8c1f303c476 ]
If we are able to load an existing inode cache off disk, we set the state
of the cache to BTRFS_CACHE_FINISHED, but we don't wake up any one waiting
for the cache to be available. This means that anyone waiting for the
cache to be available, waiting on the condition that either its state is
BTRFS_CACHE_FINISHED or its available free space is greather than zero,
can hang forever.
This could be observed running fstests with MOUNT_OPTIONS="-o inode_cache",
in particular test case generic/161 triggered it very frequently for me,
producing a trace like the following:
[63795.739712] BTRFS info (device sdc): enabling inode map caching
[63795.739714] BTRFS info (device sdc): disk space caching is enabled
[63795.739716] BTRFS info (device sdc): has skinny extents
[64036.653886] INFO: task btrfs-transacti:3917 blocked for more than 120 seconds.
[64036.654079] Not tainted 5.2.0-rc4-btrfs-next-50 #1
[64036.654143] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[64036.654232] btrfs-transacti D 0 3917 2 0x80004000
[64036.654239] Call Trace:
[64036.654258] ? __schedule+0x3ae/0x7b0
[64036.654271] schedule+0x3a/0xb0
[64036.654325] btrfs_commit_transaction+0x978/0xae0 [btrfs]
[64036.654339] ? remove_wait_queue+0x60/0x60
[64036.654395] transaction_kthread+0x146/0x180 [btrfs]
[64036.654450] ? btrfs_cleanup_transaction+0x620/0x620 [btrfs]
[64036.654456] kthread+0x103/0x140
[64036.654464] ? kthread_create_worker_on_cpu+0x70/0x70
[64036.654476] ret_from_fork+0x3a/0x50
[64036.654504] INFO: task xfs_io:3919 blocked for more than 120 seconds.
[64036.654568] Not tainted 5.2.0-rc4-btrfs-next-50 #1
[64036.654617] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[64036.654685] xfs_io D 0 3919 3633 0x00000000
[64036.654691] Call Trace:
[64036.654703] ? __schedule+0x3ae/0x7b0
[64036.654716] schedule+0x3a/0xb0
[64036.654756] btrfs_find_free_ino+0xa9/0x120 [btrfs]
[64036.654764] ? remove_wait_queue+0x60/0x60
[64036.654809] btrfs_create+0x72/0x1f0 [btrfs]
[64036.654822] lookup_open+0x6bc/0x790
[64036.654849] path_openat+0x3bc/0xc00
[64036.654854] ? __lock_acquire+0x331/0x1cb0
[64036.654869] do_filp_open+0x99/0x110
[64036.654884] ? __alloc_fd+0xee/0x200
[64036.654895] ? do_raw_spin_unlock+0x49/0xc0
[64036.654909] ? do_sys_open+0x132/0x220
[64036.654913] do_sys_open+0x132/0x220
[64036.654926] do_syscall_64+0x60/0x1d0
[64036.654933] entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fix this by adding a wake_up() call right after setting the cache state to
BTRFS_CACHE_FINISHED, at start_caching(), when we are able to load the
cache from disk.
Fixes: 82d5902d9c681b ("Btrfs: Support reading/writing on disk free ino cache")
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 26ef8493e1ab771cb01d27defca2fa1315dc3980 upstream.
When running xfstests on the current btrfs I get the following splat from
kmemleak:
unreferenced object 0xffff88821b2404e0 (size 32):
comm "kworker/u4:7", pid 26663, jiffies 4295283698 (age 8.776s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 10 ff fd 26 82 88 ff ff ...........&....
10 ff fd 26 82 88 ff ff 20 ff fd 26 82 88 ff ff ...&.... ..&....
backtrace:
[<00000000f94fd43f>] ulist_alloc+0x25/0x60 [btrfs]
[<00000000fd023d99>] btrfs_find_all_roots_safe+0x41/0x100 [btrfs]
[<000000008f17bd32>] btrfs_find_all_roots+0x52/0x70 [btrfs]
[<00000000b7660afb>] btrfs_qgroup_rescan_worker+0x343/0x680 [btrfs]
[<0000000058e66778>] btrfs_work_helper+0xac/0x1e0 [btrfs]
[<00000000f0188930>] process_one_work+0x1cf/0x350
[<00000000af5f2f8e>] worker_thread+0x28/0x3c0
[<00000000b55a1add>] kthread+0x109/0x120
[<00000000f88cbd17>] ret_from_fork+0x35/0x40
This corresponds to:
(gdb) l *(btrfs_find_all_roots_safe+0x41)
0x8d7e1 is in btrfs_find_all_roots_safe (fs/btrfs/backref.c:1413).
1408
1409 tmp = ulist_alloc(GFP_NOFS);
1410 if (!tmp)
1411 return -ENOMEM;
1412 *roots = ulist_alloc(GFP_NOFS);
1413 if (!*roots) {
1414 ulist_free(tmp);
1415 return -ENOMEM;
1416 }
1417
Following the lifetime of the allocated 'roots' ulist, it gets freed
again in btrfs_qgroup_account_extent().
But this does not happen if the function is called with the
'BTRFS_FS_QUOTA_ENABLED' flag cleared, then btrfs_qgroup_account_extent()
does a short leave and directly returns.
Instead of directly returning we should jump to the 'out_free' in order to
free all resources as expected.
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9cf35f673583ccc9f3e2507498b3079d56614ad3 upstream.
This is similar to 942491c9e6d6 ("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: edf064e7c6fe ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit c7e54b5102bf3614cadb9ca32d7be73bad6cecf0 ]
We can just abort the transaction here, and in fact do that for every
other failure in this function except these two cases.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
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[ Upstream commit b6293c821ea8fa2a631a2112cd86cd435effeb8b ]
Callers of alloc_test_extent_buffer have not correctly interpreted the
return value as error pointer, as alloc_test_extent_buffer should behave
as alloc_extent_buffer. The self-tests were unaffected but
btrfs_find_create_tree_block could call both functions and that would
cause problems up in the call chain.
Fixes: faa2dbf004e8 ("Btrfs: add sanity tests for new qgroup accounting code")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit 57d4f0b863272ba04ba85f86bfdc0f976f0af91c ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
|
[ Upstream commit e732fe95e4cad35fc1df278c23a32903341b08b3 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c495dcd6fbe1dce51811a76bb85b4675f6494938 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9be490f1e15c34193b1aae17da58e14dd9f55a95 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 6609fee8897ac475378388238456c84298bff802 upstream.
When a tree mod log user no longer needs to use the tree it calls
btrfs_put_tree_mod_seq() to remove itself from the list of users and
delete all no longer used elements of the tree's red black tree, which
should be all elements with a sequence number less then our equals to
the caller's sequence number. However the logic is broken because it
can delete and free elements from the red black tree that have a
sequence number greater then the caller's sequence number:
1) At a point in time we have sequence numbers 1, 2, 3 and 4 in the
tree mod log;
2) The task which got assigned the sequence number 1 calls
btrfs_put_tree_mod_seq();
3) Sequence number 1 is deleted from the list of sequence numbers;
4) The current minimum sequence number is computed to be the sequence
number 2;
5) A task using sequence number 2 is at tree_mod_log_rewind() and gets
a pointer to one of its elements from the red black tree through
a call to tree_mod_log_search();
6) The task with sequence number 1 iterates the red black tree of tree
modification elements and deletes (and frees) all elements with a
sequence number less then or equals to 2 (the computed minimum sequence
number) - it ends up only leaving elements with sequence numbers of 3
and 4;
7) The task with sequence number 2 now uses the pointer to its element,
already freed by the other task, at __tree_mod_log_rewind(), resulting
in a use-after-free issue. When CONFIG_DEBUG_PAGEALLOC=y it produces
a trace like the following:
[16804.546854] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
[16804.547451] CPU: 0 PID: 28257 Comm: pool Tainted: G W 5.4.0-rc8-btrfs-next-51 #1
[16804.548059] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
[16804.548666] RIP: 0010:rb_next+0x16/0x50
(...)
[16804.550581] RSP: 0018:ffffb948418ef9b0 EFLAGS: 00010202
[16804.551227] RAX: 6b6b6b6b6b6b6b6b RBX: ffff90e0247f6600 RCX: 6b6b6b6b6b6b6b6b
[16804.551873] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff90e0247f6600
[16804.552504] RBP: ffff90dffe0d4688 R08: 0000000000000001 R09: 0000000000000000
[16804.553136] R10: ffff90dffa4a0040 R11: 0000000000000000 R12: 000000000000002e
[16804.553768] R13: ffff90e0247f6600 R14: 0000000000001663 R15: ffff90dff77862b8
[16804.554399] FS: 00007f4b197ae700(0000) GS:ffff90e036a00000(0000) knlGS:0000000000000000
[16804.555039] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[16804.555683] CR2: 00007f4b10022000 CR3: 00000002060e2004 CR4: 00000000003606f0
[16804.556336] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[16804.556968] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[16804.557583] Call Trace:
[16804.558207] __tree_mod_log_rewind+0xbf/0x280 [btrfs]
[16804.558835] btrfs_search_old_slot+0x105/0xd00 [btrfs]
[16804.559468] resolve_indirect_refs+0x1eb/0xc70 [btrfs]
[16804.560087] ? free_extent_buffer.part.19+0x5a/0xc0 [btrfs]
[16804.560700] find_parent_nodes+0x388/0x1120 [btrfs]
[16804.561310] btrfs_check_shared+0x115/0x1c0 [btrfs]
[16804.561916] ? extent_fiemap+0x59d/0x6d0 [btrfs]
[16804.562518] extent_fiemap+0x59d/0x6d0 [btrfs]
[16804.563112] ? __might_fault+0x11/0x90
[16804.563706] do_vfs_ioctl+0x45a/0x700
[16804.564299] ksys_ioctl+0x70/0x80
[16804.564885] ? trace_hardirqs_off_thunk+0x1a/0x20
[16804.565461] __x64_sys_ioctl+0x16/0x20
[16804.566020] do_syscall_64+0x5c/0x250
[16804.566580] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[16804.567153] RIP: 0033:0x7f4b1ba2add7
(...)
[16804.568907] RSP: 002b:00007f4b197adc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[16804.569513] RAX: ffffffffffffffda RBX: 00007f4b100210d8 RCX: 00007f4b1ba2add7
[16804.570133] RDX: 00007f4b100210d8 RSI: 00000000c020660b RDI: 0000000000000003
[16804.570726] RBP: 000055de05a6cfe0 R08: 0000000000000000 R09: 00007f4b197add44
[16804.571314] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4b197add48
[16804.571905] R13: 00007f4b197add40 R14: 00007f4b100210d0 R15: 00007f4b197add50
(...)
[16804.575623] ---[ end trace 87317359aad4ba50 ]---
Fix this by making btrfs_put_tree_mod_seq() skip deletion of elements that
have a sequence number equals to the computed minimum sequence number, and
not just elements with a sequence number greater then that minimum.
Fixes: bd989ba359f2ac ("Btrfs: add tree modification log functions")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 714cd3e8cba6841220dce9063a7388a81de03825 upstream.
If we get an -ENOENT back from btrfs_uuid_iter_rem when iterating the
uuid tree we'll just continue and do btrfs_next_item(). However we've
done a btrfs_release_path() at this point and no longer have a valid
path. So increment the key and go back and do a normal search.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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