ext4: Replace open coded mdata csum feature to helper function

Besides the fact that this replacement improves code readability
it also protects from errors caused direct EXT4_S(sb)->s_es manipulation
which may result attempt to use uninitialized  csum machinery.

#Testcase_BEGIN
IMG=/dev/ram0
MNT=/mnt
mkfs.ext4 $IMG
mount $IMG $MNT
#Enable feature directly on disk, on mounted fs
tune2fs -O metadata_csum  $IMG
# Provoke metadata update, likey result in OOPS
touch $MNT/test
umount $MNT
#Testcase_END

# Replacement script
@@
expression E;
@@
- EXT4_HAS_RO_COMPAT_FEATURE(E, EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)
+ ext4_has_metadata_csum(E)

https://bugzilla.kernel.org/show_bug.cgi?id=82201

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

1 files changed, 1 insertions, 2 deletions

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 378aadf5e6db..3ea62695abce 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -1128,8 +1128,7 @@ static int ext4_finish_convert_inline_dir(handle_t *handle,
         memcpy((void *)de, buf + EXT4_INLINE_DOTDOT_SIZE,
                 inline_size - EXT4_INLINE_DOTDOT_SIZE);
 
-        if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-                                       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+        if (ext4_has_metadata_csum(inode->i_sb))
                 csum_size = sizeof(struct ext4_dir_entry_tail);
 
         inode->i_size = inode->i_sb->s_blocksize;