6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qu Wenruo [ Upstream commit 9102b179512e11644fb0489ae62010a09afa199c ] In that function, we round down the start position and round up the ending position. But during the calculation of @len, we use "round_up(start + len, sectorsize)", which is the rounded up end position, not the rounded up length. Which results a much larger length, and later we are still using "start + len", which is completely incorrect. Fix it by declaring a local @aligned_start and @aligned_len and use them instead. Fixes: bc42bda22345 ("btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges") Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/qgroup.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 5b158eb25d181..57552c414b43a 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -4371,12 +4371,13 @@ static int qgroup_free_reserved_data(struct btrfs_inode *inode, struct ulist_node *unode; struct ulist_iterator uiter; struct extent_changeset changeset; + const u32 sectorsize = root->fs_info->sectorsize; + const u64 aligned_start = round_down(start, sectorsize); + const u64 aligned_len = round_up(start + len, sectorsize) - aligned_start; u64 freed = 0; int ret; extent_changeset_init(&changeset); - len = round_up(start + len, root->fs_info->sectorsize); - start = round_down(start, root->fs_info->sectorsize); ULIST_ITER_INIT(&uiter); while ((unode = ulist_next(&reserved->range_changed, &uiter))) { @@ -4388,12 +4389,15 @@ static int qgroup_free_reserved_data(struct btrfs_inode *inode, extent_changeset_release(&changeset); - /* Only free range in range [start, start + len) */ - if (range_start >= start + len || - range_start + range_len <= start) + /* + * Only free the range within + * [aligned_start, aligned_start + aligned_len). + */ + if (range_start >= aligned_start + aligned_len || + range_start + range_len <= aligned_start) continue; - free_start = max(range_start, start); - free_len = min(start + len, range_start + range_len) - + free_start = max(range_start, aligned_start); + free_len = min(aligned_start + aligned_len, range_start + range_len) - free_start; /* * TODO: To also modify reserved->ranges_reserved to reflect -- 2.53.0