f2fs: support inode checksum

This patch adds to support inode checksum in f2fs.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix verification flow]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1c31e4e..7c1244b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -116,6 +116,7 @@ struct f2fs_mount_info {
 #define F2FS_FEATURE_ATOMIC_WRITE	0x0004
 #define F2FS_FEATURE_EXTRA_ATTR		0x0008
 #define F2FS_FEATURE_PRJQUOTA		0x0010
+#define F2FS_FEATURE_INODE_CHKSUM	0x0020
 
 #define F2FS_HAS_FEATURE(sb, mask)					\
 	((F2FS_SB(sb)->raw_super->feature & cpu_to_le32(mask)) != 0)
@@ -1085,6 +1086,9 @@ struct f2fs_sb_info {
 	/* Reference to checksum algorithm driver via cryptoapi */
 	struct crypto_shash *s_chksum_driver;
 
+	/* Precomputed FS UUID checksum for seeding other checksums */
+	__u32 s_chksum_seed;
+
 	/* For fault injection */
 #ifdef CONFIG_F2FS_FAULT_INJECTION
 	struct f2fs_fault_info fault_info;
@@ -1176,6 +1180,27 @@ static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 blk_crc,
 	return f2fs_crc32(sbi, buf, buf_size) == blk_crc;
 }
 
+static inline u32 f2fs_chksum(struct f2fs_sb_info *sbi, u32 crc,
+			      const void *address, unsigned int length)
+{
+	struct {
+		struct shash_desc shash;
+		char ctx[4];
+	} desc;
+	int err;
+
+	BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != sizeof(desc.ctx));
+
+	desc.shash.tfm = sbi->s_chksum_driver;
+	desc.shash.flags = 0;
+	*(u32 *)desc.ctx = crc;
+
+	err = crypto_shash_update(&desc.shash, address, length);
+	BUG_ON(err);
+
+	return *(u32 *)desc.ctx;
+}
+
 static inline struct f2fs_inode_info *F2FS_I(struct inode *inode)
 {
 	return container_of(inode, struct f2fs_inode_info, vfs_inode);
@@ -2285,6 +2310,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
  * inode.c
  */
 void f2fs_set_inode_flags(struct inode *inode);
+bool f2fs_inode_chksum_verify(struct f2fs_sb_info *sbi, struct page *page);
+void f2fs_inode_chksum_set(struct f2fs_sb_info *sbi, struct page *page);
 struct inode *f2fs_iget(struct super_block *sb, unsigned long ino);
 struct inode *f2fs_iget_retry(struct super_block *sb, unsigned long ino);
 int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink);
@@ -2869,6 +2896,11 @@ static inline int f2fs_sb_has_project_quota(struct super_block *sb)
 	return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_PRJQUOTA);
 }
 
+static inline int f2fs_sb_has_inode_chksum(struct super_block *sb)
+{
+	return F2FS_HAS_FEATURE(sb, F2FS_FEATURE_INODE_CHKSUM);
+}
+
 #ifdef CONFIG_BLK_DEV_ZONED
 static inline int get_blkz_type(struct f2fs_sb_info *sbi,
 			struct block_device *bdev, block_t blkaddr)