[PATCH v2 3/7] ext4: avoid negative min_clusters in find_group_orlov()

Kemeng Shi posted 7 patches 1 year, 5 months ago
[PATCH v2 3/7] ext4: avoid negative min_clusters in find_group_orlov()
Posted by Kemeng Shi 1 year, 5 months ago
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.

Fixes: ac27a0ec112a ("[PATCH] ext4: initial copy of files from ext3")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/ext4/ialloc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 9e2c08a8665f..81641be38c0e 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