[PATCH 3/7] ext4: avoid negative min_clusters in find_group_orlov

From: Kemeng Shi
Date: Tue Aug 13 2024 - 08:11:09 EST


min_clusters is signed integer and will be converted to unsigned
integer when compared with unsigned number stats.free_clusters.
If min_clusters is negative, it will be converted to a huge unsigned
value in which case all groups may not meet the actual desired free
clusters.
Set negative min_clusters to 0 to avoid unexpected behavior.

Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
---
fs/ext4/ialloc.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index f24a238b6b09..df41aa079cb5 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -514,6 +514,8 @@ static int find_group_orlov(struct super_block *sb, struct inode *parent,
if (min_inodes < 1)
min_inodes = 1;
min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
+ if (min_clusters < 0)
+ min_clusters = 0;

/*
* Start looking in the flex group where we last allocated an
--
2.30.0