From: Naohiro Aota naohiro.aota@wdc.com
commit 6d82ad13c4110e73c7b0392f00534a1502a1b520 upstream.
Running generic/406 causes the following WARNING in btrfs_destroy_inode() which tells there are outstanding extents left.
In btrfs_get_blocks_direct_write(), we reserve a temporary outstanding extents with btrfs_delalloc_reserve_metadata() (or indirectly from btrfs_delalloc_reserve_space(()). We then release the outstanding extents with btrfs_delalloc_release_extents(). However, the "len" can be modified in the COW case, which releases fewer outstanding extents than expected.
Fix it by calling btrfs_delalloc_release_extents() for the original length.
To reproduce the warning, the filesystem should be 1 GiB. It's triggering a short-write, due to not being able to allocate a large extent and instead allocating a smaller one.
WARNING: CPU: 0 PID: 757 at fs/btrfs/inode.c:8848 btrfs_destroy_inode+0x1e6/0x210 [btrfs] Modules linked in: btrfs blake2b_generic xor lzo_compress lzo_decompress raid6_pq zstd zstd_decompress zstd_compress xxhash zram zsmalloc CPU: 0 PID: 757 Comm: umount Not tainted 5.17.0-rc8+ #101 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014 RIP: 0010:btrfs_destroy_inode+0x1e6/0x210 [btrfs] RSP: 0018:ffffc9000327bda8 EFLAGS: 00010206 RAX: 0000000000000000 RBX: ffff888100548b78 RCX: 0000000000000000 RDX: 0000000000026900 RSI: 0000000000000000 RDI: ffff888100548b78 RBP: ffff888100548940 R08: 0000000000000000 R09: ffff88810b48aba8 R10: 0000000000000001 R11: ffff8881004eb240 R12: ffff88810b48a800 R13: ffff88810b48ec08 R14: ffff88810b48ed00 R15: ffff888100490c68 FS: 00007f8549ea0b80(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f854a09e733 CR3: 000000010a2e9003 CR4: 0000000000370eb0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> destroy_inode+0x33/0x70 dispose_list+0x43/0x60 evict_inodes+0x161/0x1b0 generic_shutdown_super+0x2d/0x110 kill_anon_super+0xf/0x20 btrfs_kill_super+0xd/0x20 [btrfs] deactivate_locked_super+0x27/0x90 cleanup_mnt+0x12c/0x180 task_work_run+0x54/0x80 exit_to_user_mode_prepare+0x152/0x160 syscall_exit_to_user_mode+0x12/0x30 do_syscall_64+0x42/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f854a000fb7
Fixes: f0bfa76a11e9 ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range") CC: stable@vger.kernel.org # 5.17 Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Tested-by: Johannes Thumshirn johannes.thumshirn@wdc.com Reviewed-by: Filipe Manana fdmanana@suse.com Signed-off-by: Naohiro Aota naohiro.aota@wdc.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7423,6 +7423,7 @@ static int btrfs_get_blocks_direct_write u64 block_start, orig_start, orig_block_len, ram_bytes; bool can_nocow = false; bool space_reserved = false; + u64 prev_len; int ret = 0;
/* @@ -7450,6 +7451,7 @@ static int btrfs_get_blocks_direct_write can_nocow = true; }
+ prev_len = len; if (can_nocow) { struct extent_map *em2;
@@ -7479,8 +7481,6 @@ static int btrfs_get_blocks_direct_write goto out; } } else { - const u64 prev_len = len; - /* Our caller expects us to free the input extent map. */ free_extent_map(em); *map = NULL; @@ -7511,7 +7511,7 @@ static int btrfs_get_blocks_direct_write * We have created our ordered extent, so we can now release our reservation * for an outstanding extent. */ - btrfs_delalloc_release_extents(BTRFS_I(inode), len); + btrfs_delalloc_release_extents(BTRFS_I(inode), prev_len);
/* * Need to update the i_size under the extent lock so buffered