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

12 files changed, 43 insertions, 70 deletions

diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index 3285aa5a706a..b610779a958c 100644
--- a/fs/ext4/bitmap.c
+++ b/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);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 012e89bd9644..1483d9c6061f 100644
--- a/fs/ext4/ext4.h
+++ b/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) |
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index c3ed9af20d20..37043d0b2be8 100644
--- a/fs/ext4/extents.c
+++ b/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);
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 5b87fc36aab8..8012a5daf401 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -1011,8 +1011,7 @@ got:
         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);
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;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0dd9150c0c04..e9777f93cf05 100644
--- a/fs/ext4/inode.c
+++ b/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);
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 3d5de16f028f..bfda18a15592 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -331,8 +331,7 @@ flags_out:
                 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;
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 32bce844c2e1..8313ca3324ec 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -20,8 +20,7 @@ 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);
@@ -29,8 +28,7 @@ static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *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);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 7037ecf0fc23..61756f941ed0 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)) {
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index bb0e80f03e2e..d5afb0a0cf25 100644
--- a/fs/ext4/resize.c
+++ b/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);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a0811cc00c91..5afe42db303c 100644
--- a/fs/ext4/super.c
+++ b/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));
 
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 42823ab3718c..1e09fc77395c 100644
--- a/fs/ext4/xattr.c
+++ b/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);