[PATCH V3] ext4: check hash version and filesystem casefolded consistent

[Lizhi Xu]

When mounting the ext4 filesystem, if the hash version and casefolded are not
consistent, exit the mounting.

Reported-by: syzbot+340581ba9dceb7e06fb3@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Lizhi Xu <lizhi.xu@xxxxxxxxxxxxx>
---
 fs/ext4/super.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c682fb927b64..c0036e3922c2 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5262,6 +5262,9 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 		goto failed_mount;
 
 	ext4_hash_info_init(sb);
+	if (es->s_def_hash_version == DX_HASH_SIPHASH && 
+	    !ext4_has_feature_casefold(sb))
+		goto failed_mount;
 
 	err = ext4_handle_clustersize(sb);
 	if (err)
-- 
2.43.0