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, 13 insertions, 26 deletions

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 7037ecf..61756f9 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -124,8 +124,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
 		       "directory leaf block found instead of index block");
 		return ERR_PTR(-EIO);
 	}
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) ||
+	if (!ext4_has_metadata_csum(inode->i_sb) ||
 	    buffer_verified(bh))
 		return bh;
 
@@ -338,8 +337,7 @@ int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
 {
 	struct ext4_dir_entry_tail *t;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(inode->i_sb))
 		return 1;
 
 	t = get_dirent_tail(inode, dirent);
@@ -360,8 +358,7 @@ static void ext4_dirent_csum_set(struct inode *inode,
 {
 	struct ext4_dir_entry_tail *t;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(inode->i_sb))
 		return;
 
 	t = get_dirent_tail(inode, dirent);
@@ -436,8 +433,7 @@ static int ext4_dx_csum_verify(struct inode *inode,
 	struct dx_tail *t;
 	int count_offset, limit, count;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(inode->i_sb))
 		return 1;
 
 	c = get_dx_countlimit(inode, dirent, &count_offset);
@@ -466,8 +462,7 @@ static void ext4_dx_csum_set(struct inode *inode, struct ext4_dir_entry *dirent)
 	struct dx_tail *t;
 	int count_offset, limit, count;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(inode->i_sb))
 		return;
 
 	c = get_dx_countlimit(inode, dirent, &count_offset);
@@ -555,8 +550,7 @@ static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
 	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
 		EXT4_DIR_REC_LEN(2) - infosize;
 
-	if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (ext4_has_metadata_csum(dir->i_sb))
 		entry_space -= sizeof(struct dx_tail);
 	return entry_space / sizeof(struct dx_entry);
 }
@@ -565,8 +559,7 @@ static inline unsigned dx_node_limit(struct inode *dir)
 {
 	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
 
-	if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (ext4_has_metadata_csum(dir->i_sb))
 		entry_space -= sizeof(struct dx_tail);
 	return entry_space / sizeof(struct dx_entry);
 }
@@ -1524,8 +1517,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
 	int	csum_size = 0;
 	int	err = 0, i;
 
-	if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (ext4_has_metadata_csum(dir->i_sb))
 		csum_size = sizeof(struct ext4_dir_entry_tail);
 
 	bh2 = ext4_append(handle, dir, &newblock);
@@ -1691,8 +1683,7 @@ static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
 	int		csum_size = 0;
 	int		err;
 
-	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);
 
 	if (!de) {
@@ -1759,8 +1750,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
 	struct fake_dirent *fde;
 	int		csum_size = 0;
 
-	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);
 
 	blocksize =  dir->i_sb->s_blocksize;
@@ -1877,8 +1867,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
 	ext4_lblk_t block, blocks;
 	int	csum_size = 0;
 
-	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);
 
 	sb = dir->i_sb;
@@ -2142,8 +2131,7 @@ static int ext4_delete_entry(handle_t *handle,
 			return err;
 	}
 
-	if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (ext4_has_metadata_csum(dir->i_sb))
 		csum_size = sizeof(struct ext4_dir_entry_tail);
 
 	BUFFER_TRACE(bh, "get_write_access");
@@ -2362,8 +2350,7 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
 	int csum_size = 0;
 	int err;
 
-	if (EXT4_HAS_RO_COMPAT_FEATURE(dir->i_sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (ext4_has_metadata_csum(dir->i_sb))
 		csum_size = sizeof(struct ext4_dir_entry_tail);
 
 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {