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| author | Robbie Ko <robbieko@synology.com> | 2019-03-26 06:56:11 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2019-04-29 20:02:39 +0300 |
| commit | 39ad317315887c2cb9a4347a93a8859326ddf136 (patch) | |
| tree | ff11aa9db53f7f56ce4468a99f17c9e68e6e6b7e /fs/btrfs/file.c | |
| parent | 178507595c934463da440fef8a0341f9a867ba38 (diff) | |
| download | linux-39ad317315887c2cb9a4347a93a8859326ddf136.tar.xz | |
Btrfs: fix data bytes_may_use underflow with fallocate due to failed quota reserve
When doing fallocate, we first add the range to the reserve_list and
then reserve the quota. If quota reservation fails, we'll release all
reserved parts of reserve_list.
However, cur_offset is not updated to indicate that this range is
already been inserted into the list. Therefore, the same range is freed
twice. Once at list_for_each_entry loop, and once at the end of the
function. This will result in WARN_ON on bytes_may_use when we free the
remaining space.
At the end, under the 'out' label we have a call to:
btrfs_free_reserved_data_space(inode, data_reserved, alloc_start, alloc_end - cur_offset);
The start offset, third argument, should be cur_offset.
Everything from alloc_start to cur_offset was freed by the
list_for_each_entry_safe_loop.
Fixes: 18513091af94 ("btrfs: update btrfs_space_info's bytes_may_use timely")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 15cc3b861346..c857a884a90f 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -3131,6 +3131,7 @@ static long btrfs_fallocate(struct file *file, int mode, ret = btrfs_qgroup_reserve_data(inode, &data_reserved, cur_offset, last_byte - cur_offset); if (ret < 0) { + cur_offset = last_byte; free_extent_map(em); break; } @@ -3180,7 +3181,7 @@ out: /* Let go of our reservation. */ if (ret != 0 && !(mode & FALLOC_FL_ZERO_RANGE)) btrfs_free_reserved_data_space(inode, data_reserved, - alloc_start, alloc_end - cur_offset); + cur_offset, alloc_end - cur_offset); extent_changeset_free(data_reserved); return ret; } |