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>

fs/ext4/bitmap.c

@@ -24,8 +24,7 @@ int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
 	__u32 provided, calculated;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return 1;
 
 	provided = le16_to_cpu(gdp->bg_inode_bitmap_csum_lo);
@@ -46,8 +45,7 @@ void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 	__u32 csum;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return;
 
 	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);
@@ -65,8 +63,7 @@ int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	int sz = EXT4_CLUSTERS_PER_GROUP(sb) / 8;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return 1;
 
 	provided = le16_to_cpu(gdp->bg_block_bitmap_csum_lo);
@@ -91,8 +88,7 @@ void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
 	__u32 csum;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return;
 
 	csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)bh->b_data, sz);

fs/ext4/ext4.h

@@ -2337,6 +2337,14 @@ static inline int ext4_has_group_desc_csum(struct super_block *sb)
 					  EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
 }
 
+static inline int ext4_has_metadata_csum(struct super_block *sb)
+{
+	WARN_ON_ONCE(EXT4_HAS_RO_COMPAT_FEATURE(sb,
+			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+		     !EXT4_SB(sb)->s_chksum_driver);
+
+	return (EXT4_SB(sb)->s_chksum_driver != NULL);
+}
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {
 	return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |

fs/ext4/extents.c

@@ -73,8 +73,7 @@ static int ext4_extent_block_csum_verify(struct inode *inode,
 {
 	struct ext4_extent_tail *et;
 
-	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;
 
 	et = find_ext4_extent_tail(eh);
@@ -88,8 +87,7 @@ static void ext4_extent_block_csum_set(struct inode *inode,
 {
 	struct ext4_extent_tail *et;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(inode->i_sb))
 		return;
 
 	et = find_ext4_extent_tail(eh);

fs/ext4/ialloc.c

@@ -1011,8 +1011,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 	spin_unlock(&sbi->s_next_gen_lock);
 
 	/* Precompute checksum seed for inode metadata */
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+	if (ext4_has_metadata_csum(sb)) {
 		__u32 csum;
 		__le32 inum = cpu_to_le32(inode->i_ino);
 		__le32 gen = cpu_to_le32(inode->i_generation);

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;

fs/ext4/inode.c

@@ -83,8 +83,7 @@ static int ext4_inode_csum_verify(struct inode *inode, struct ext4_inode *raw,
 
 	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 	    cpu_to_le32(EXT4_OS_LINUX) ||
-	    !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	    !ext4_has_metadata_csum(inode->i_sb))
 		return 1;
 
 	provided = le16_to_cpu(raw->i_checksum_lo);
@@ -105,8 +104,7 @@ static void ext4_inode_csum_set(struct inode *inode, struct ext4_inode *raw,
 
 	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 	    cpu_to_le32(EXT4_OS_LINUX) ||
-	    !EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	    !ext4_has_metadata_csum(inode->i_sb))
 		return;
 
 	csum = ext4_inode_csum(inode, raw, ei);
@@ -3928,8 +3926,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 		ei->i_extra_isize = 0;
 
 	/* Precompute checksum seed for inode metadata */
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+	if (ext4_has_metadata_csum(sb)) {
 		struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 		__u32 csum;
 		__le32 inum = cpu_to_le32(inode->i_ino);

fs/ext4/ioctl.c

@@ -331,8 +331,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!inode_owner_or_capable(inode))
 			return -EPERM;
 
-		if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-				EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+		if (ext4_has_metadata_csum(inode->i_sb)) {
 			ext4_warning(sb, "Setting inode version is not "
 				     "supported with metadata_csum enabled.");
 			return -ENOTTY;

fs/ext4/mmp.c

@@ -20,17 +20,15 @@ static __le32 ext4_mmp_csum(struct super_block *sb, struct mmp_struct *mmp)
 
 static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *mmp)
 {
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return 1;
 
 	return mmp->mmp_checksum == ext4_mmp_csum(sb, mmp);
 }
 
 static void ext4_mmp_csum_set(struct super_block *sb, struct mmp_struct *mmp)
 {
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return;
 
 	mmp->mmp_checksum = ext4_mmp_csum(sb, mmp);

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)) {

fs/ext4/resize.c

@@ -1210,8 +1210,7 @@ static int ext4_set_bitmap_checksums(struct super_block *sb,
 {
 	struct buffer_head *bh;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-					EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return 0;
 
 	bh = ext4_get_bitmap(sb, group_data->inode_bitmap);

fs/ext4/super.c

@@ -140,8 +140,7 @@ static __le32 ext4_superblock_csum(struct super_block *sb,
 static int ext4_superblock_csum_verify(struct super_block *sb,
 				       struct ext4_super_block *es)
 {
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return 1;
 
 	return es->s_checksum == ext4_superblock_csum(sb, es);
@@ -151,8 +150,7 @@ void ext4_superblock_csum_set(struct super_block *sb)
 {
 	struct ext4_super_block *es = EXT4_SB(sb)->s_es;
 
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
-		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(sb))
 		return;
 
 	es->s_checksum = ext4_superblock_csum(sb, es);
@@ -1989,8 +1987,7 @@ static __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
 	__u16 crc = 0;
 	__le32 le_group = cpu_to_le32(block_group);
 
-	if ((sbi->s_es->s_feature_ro_compat &
-	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))) {
+	if (ext4_has_metadata_csum(sbi->s_sb)) {
 		/* Use new metadata_csum algorithm */
 		__le16 save_csum;
 		__u32 csum32;
@@ -3199,8 +3196,7 @@ static int set_journal_csum_feature_set(struct super_block *sb)
 	int compat, incompat;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-				       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+	if (ext4_has_metadata_csum(sb)) {
 		/* journal checksum v3 */
 		compat = 0;
 		incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
@@ -3508,8 +3504,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* Precompute checksum seed for all metadata */
-	if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
-			EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (ext4_has_metadata_csum(sb))
 		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
 					       sizeof(es->s_uuid));
 

fs/ext4/xattr.c

@@ -142,8 +142,7 @@ static int ext4_xattr_block_csum_verify(struct inode *inode,
 					sector_t block_nr,
 					struct ext4_xattr_header *hdr)
 {
-	if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+	if (ext4_has_metadata_csum(inode->i_sb) &&
 	    (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr)))
 		return 0;
 	return 1;
@@ -153,8 +152,7 @@ static void ext4_xattr_block_csum_set(struct inode *inode,
 				      sector_t block_nr,
 				      struct ext4_xattr_header *hdr)
 {
-	if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
-		EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+	if (!ext4_has_metadata_csum(inode->i_sb))
 		return;
 
 	hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr);