Skip to content

Commit

Permalink
btrfs: fix assertion failure when splitting ordered extent after tran…
Browse files Browse the repository at this point in the history 
…saction abort

If while we are doing a direct IO write a transaction abort happens, we
mark all existing ordered extents with the BTRFS_ORDERED_IOERR flag (done
at btrfs_destroy_ordered_extents()), and then after that if we enter
btrfs_split_ordered_extent() and the ordered extent has bytes left
(meaning we have a bio that doesn't cover the whole ordered extent, see
details at btrfs_extract_ordered_extent()), we will fail on the following
assertion at btrfs_split_ordered_extent():

   ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));

because the BTRFS_ORDERED_IOERR flag is set and the definition of
BTRFS_ORDERED_TYPE_FLAGS is just the union of all flags that identify the
type of write (regular, nocow, prealloc, compressed, direct IO, encoded).

Fix this by returning an error from btrfs_extract_ordered_extent() if we
find the BTRFS_ORDERED_IOERR flag in the ordered extent. The error will
be the error that resulted in the transaction abort or -EIO if no
transaction abort happened.

This was recently reported by syzbot with the following trace:

   FAULT_INJECTION: forcing a failure.
   name failslab, interval 1, probability 0, space 0, times 1
   CPU: 0 UID: 0 PID: 5321 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller #0
   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
   Call Trace:
    <TASK>
    __dump_stack lib/dump_stack.c:94 [inline]
    dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
    fail_dump lib/fault-inject.c:53 [inline]
    should_fail_ex+0x3b0/0x4e0 lib/fault-inject.c:154
    should_failslab+0xac/0x100 mm/failslab.c:46
    slab_pre_alloc_hook mm/slub.c:4072 [inline]
    slab_alloc_node mm/slub.c:4148 [inline]
    __do_kmalloc_node mm/slub.c:4297 [inline]
    __kmalloc_noprof+0xdd/0x4c0 mm/slub.c:4310
    kmalloc_noprof include/linux/slab.h:905 [inline]
    kzalloc_noprof include/linux/slab.h:1037 [inline]
    btrfs_chunk_alloc_add_chunk_item+0x244/0x1100 fs/btrfs/volumes.c:5742
    reserve_chunk_space+0x1ca/0x2c0 fs/btrfs/block-group.c:4292
    check_system_chunk fs/btrfs/block-group.c:4319 [inline]
    do_chunk_alloc fs/btrfs/block-group.c:3891 [inline]
    btrfs_chunk_alloc+0x77b/0xf80 fs/btrfs/block-group.c:4187
    find_free_extent_update_loop fs/btrfs/extent-tree.c:4166 [inline]
    find_free_extent+0x42d1/0x5810 fs/btrfs/extent-tree.c:4579
    btrfs_reserve_extent+0x422/0x810 fs/btrfs/extent-tree.c:4672
    btrfs_new_extent_direct fs/btrfs/direct-io.c:186 [inline]
    btrfs_get_blocks_direct_write+0x706/0xfa0 fs/btrfs/direct-io.c:321
    btrfs_dio_iomap_begin+0xbb7/0x1180 fs/btrfs/direct-io.c:525
    iomap_iter+0x697/0xf60 fs/iomap/iter.c:90
    __iomap_dio_rw+0xeb9/0x25b0 fs/iomap/direct-io.c:702
    btrfs_dio_write fs/btrfs/direct-io.c:775 [inline]
    btrfs_direct_write+0x610/0xa30 fs/btrfs/direct-io.c:880
    btrfs_do_write_iter+0x2a0/0x760 fs/btrfs/file.c:1397
    do_iter_readv_writev+0x600/0x880
    vfs_writev+0x376/0xba0 fs/read_write.c:1050
    do_pwritev fs/read_write.c:1146 [inline]
    __do_sys_pwritev2 fs/read_write.c:1204 [inline]
    __se_sys_pwritev2+0x196/0x2b0 fs/read_write.c:1195
    do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   RIP: 0033:0x7f1281f85d29
   RSP: 002b:00007f12819fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
   RAX: ffffffffffffffda RBX: 00007f1282176080 RCX: 00007f1281f85d29
   RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000005
   RBP: 00007f12819fe090 R08: 0000000000000000 R09: 0000000000000003
   R10: 0000000000007000 R11: 0000000000000246 R12: 0000000000000002
   R13: 0000000000000000 R14: 00007f1282176080 R15: 00007ffcb9e23328
    </TASK>
   BTRFS error (device loop0 state A): Transaction aborted (error -12)
   BTRFS: error (device loop0 state A) in btrfs_chunk_alloc_add_chunk_item:5745: errno=-12 Out of memory
   BTRFS info (device loop0 state EA): forced readonly
   assertion failed: !(flags & ~BTRFS_ORDERED_TYPE_FLAGS), in fs/btrfs/ordered-data.c:1234
   ------------[ cut here ]------------
   kernel BUG at fs/btrfs/ordered-data.c:1234!
   Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
   CPU: 0 UID: 0 PID: 5321 Comm: syz.0.0 Not tainted 6.13.0-rc5-syzkaller #0
   Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
   RIP: 0010:btrfs_split_ordered_extent+0xd8d/0xe20 fs/btrfs/ordered-data.c:1234
   RSP: 0018:ffffc9000d1df2b8 EFLAGS: 00010246
   RAX: 0000000000000057 RBX: 000000000006a000 RCX: 9ce21886c4195300
   RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
   RBP: 0000000000000091 R08: ffffffff817f0a3c R09: 1ffff92001a3bdf4
   R10: dffffc0000000000 R11: fffff52001a3bdf5 R12: 1ffff1100a45f401
   R13: ffff8880522fa018 R14: dffffc0000000000 R15: 000000000006a000
   FS:  00007f12819fe6c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 0000557750bd7da8 CR3: 00000000400ea000 CR4: 0000000000352ef0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   Call Trace:
    <TASK>
    btrfs_extract_ordered_extent fs/btrfs/direct-io.c:702 [inline]
    btrfs_dio_submit_io+0x4be/0x6d0 fs/btrfs/direct-io.c:737
    iomap_dio_submit_bio fs/iomap/direct-io.c:85 [inline]
    iomap_dio_bio_iter+0x1022/0x1740 fs/iomap/direct-io.c:447
    __iomap_dio_rw+0x13b7/0x25b0 fs/iomap/direct-io.c:703
    btrfs_dio_write fs/btrfs/direct-io.c:775 [inline]
    btrfs_direct_write+0x610/0xa30 fs/btrfs/direct-io.c:880
    btrfs_do_write_iter+0x2a0/0x760 fs/btrfs/file.c:1397
    do_iter_readv_writev+0x600/0x880
    vfs_writev+0x376/0xba0 fs/read_write.c:1050
    do_pwritev fs/read_write.c:1146 [inline]
    __do_sys_pwritev2 fs/read_write.c:1204 [inline]
    __se_sys_pwritev2+0x196/0x2b0 fs/read_write.c:1195
    do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
    entry_SYSCALL_64_after_hwframe+0x77/0x7f
   RIP: 0033:0x7f1281f85d29
   RSP: 002b:00007f12819fe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
   RAX: ffffffffffffffda RBX: 00007f1282176080 RCX: 00007f1281f85d29
   RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000005
   RBP: 00007f12819fe090 R08: 0000000000000000 R09: 0000000000000003
   R10: 0000000000007000 R11: 0000000000000246 R12: 0000000000000002
   R13: 0000000000000000 R14: 00007f1282176080 R15: 00007ffcb9e23328
    </TASK>
   Modules linked in:
   ---[ end trace 0000000000000000 ]---
   RIP: 0010:btrfs_split_ordered_extent+0xd8d/0xe20 fs/btrfs/ordered-data.c:1234
   RSP: 0018:ffffc9000d1df2b8 EFLAGS: 00010246
   RAX: 0000000000000057 RBX: 000000000006a000 RCX: 9ce21886c4195300
   RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
   RBP: 0000000000000091 R08: ffffffff817f0a3c R09: 1ffff92001a3bdf4
   R10: dffffc0000000000 R11: fffff52001a3bdf5 R12: 1ffff1100a45f401
   R13: ffff8880522fa018 R14: dffffc0000000000 R15: 000000000006a000
   FS:  00007f12819fe6c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 0000557750bd7da8 CR3: 00000000400ea000 CR4: 0000000000352ef0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

In this case the transaction abort was due to (an injected) memory
allocation failure when attempting to allocate a new chunk.

Reported-by: [email protected]
Link: https://lore.kernel.org/linux-btrfs/[email protected]/
Fixes: 52b1fdc ("btrfs: handle completed ordered extents in btrfs_split_ordered_extent")
Reviewed-by: Qu Wenruo <[email protected]>
Signed-off-by: Filipe Manana <[email protected]>
Signed-off-by: David Sterba <[email protected]>
  • Loading branch information
@fdmanana @kdave
fdmanana authored and kdave committed Jan 23, 2025
1 parent dca7c74 commit 0235c94
Showing 1 changed file with 12 additions and 0 deletions.
12 changes: 12 additions & 0 deletions fs/btrfs/ordered-data.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1229,6 +1229,18 @@ struct btrfs_ordered_extent *btrfs_split_ordered_extent(
*/
if (WARN_ON_ONCE(len >= ordered->num_bytes))
return ERR_PTR(-EINVAL);
/*
* If our ordered extent had an error there's no point in continuing.
* The error may have come from a transaction abort done either by this
* task or some other concurrent task, and the transaction abort path
* iterates over all existing ordered extents and sets the flag
* BTRFS_ORDERED_IOERR on them.
*/
if (unlikely(flags & (1U << BTRFS_ORDERED_IOERR))) {
const int fs_error = BTRFS_FS_ERROR(fs_info);

return fs_error ? ERR_PTR(fs_error) : ERR_PTR(-EIO);
}
/* We cannot split partially completed ordered extents. */
if (ordered->bytes_left) {
ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
Expand Down

0 comments on commit 0235c94

Please sign in to comment.