path: root/fs
diff options
authorRobbie Ko <robbieko@synology.com>2019-03-26 11:56:11 +0800
committerPaul Gortmaker <paul.gortmaker@windriver.com>2019-08-02 19:19:16 -0400
commita885fd880e6fb1f29b4184e00a40152a29442bb5 (patch)
tree314506272d045be2cee33caa3e4f67521bd69cbd /fs
parent16580af545a1605586f404d28a2175b253d5e05d (diff)
Btrfs: fix data bytes_may_use underflow with fallocate due to failed quota reserve
commit 39ad317315887c2cb9a4347a93a8859326ddf136 upstream. 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> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Diffstat (limited to 'fs')
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 0721e2c33c84..70a22e58d685 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3225,6 +3225,7 @@ 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;
@@ -3274,7 +3275,7 @@ 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);
return ret;