ext4: factor out ext4_init_metadata_csum()

Factor out ext4_init_metadata_csum(). No functional change.
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/20220916141527.1012715-9-yanaijie@huawei.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/super.c

@@ -4540,6 +4540,50 @@ static inline int ext4_encoding_init(struct super_block *sb, struct ext4_super_b
 }
 #endif
 
+static int ext4_init_metadata_csum(struct super_block *sb, struct ext4_super_block *es)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+	/* Warn if metadata_csum and gdt_csum are both set. */
+	if (ext4_has_feature_metadata_csum(sb) &&
+	    ext4_has_feature_gdt_csum(sb))
+		ext4_warning(sb, "metadata_csum and uninit_bg are "
+			     "redundant flags; please run fsck.");
+
+	/* Check for a known checksum algorithm */
+	if (!ext4_verify_csum_type(sb, es)) {
+		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
+			 "unknown checksum algorithm.");
+		return -EINVAL;
+	}
+	ext4_setup_csum_trigger(sb, EXT4_JTR_ORPHAN_FILE,
+				ext4_orphan_file_block_trigger);
+
+	/* Load the checksum driver */
+	sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
+	if (IS_ERR(sbi->s_chksum_driver)) {
+		int ret = PTR_ERR(sbi->s_chksum_driver);
+		ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
+		sbi->s_chksum_driver = NULL;
+		return ret;
+	}
+
+	/* Check superblock checksum */
+	if (!ext4_superblock_csum_verify(sb, es)) {
+		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
+			 "invalid superblock checksum.  Run e2fsck?");
+		return -EFSBADCRC;
+	}
+
+	/* Precompute checksum seed for all metadata */
+	if (ext4_has_feature_csum_seed(sb))
+		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
+	else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
+		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
+					       sizeof(es->s_uuid));
+	return 0;
+}
+
 static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 {
 	struct buffer_head *bh, **group_desc;
@@ -4609,44 +4653,9 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
 
 	sbi->s_kbytes_written = le64_to_cpu(es->s_kbytes_written);
 
-	/* Warn if metadata_csum and gdt_csum are both set. */
-	if (ext4_has_feature_metadata_csum(sb) &&
-	    ext4_has_feature_gdt_csum(sb))
-		ext4_warning(sb, "metadata_csum and uninit_bg are "
-			     "redundant flags; please run fsck.");
-
-	/* Check for a known checksum algorithm */
-	if (!ext4_verify_csum_type(sb, es)) {
-		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
-			 "unknown checksum algorithm.");
-		goto failed_mount;
-	}
-	ext4_setup_csum_trigger(sb, EXT4_JTR_ORPHAN_FILE,
-				ext4_orphan_file_block_trigger);
-
-	/* Load the checksum driver */
-	sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
-	if (IS_ERR(sbi->s_chksum_driver)) {
-		ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver.");
-		ret = PTR_ERR(sbi->s_chksum_driver);
-		sbi->s_chksum_driver = NULL;
-		goto failed_mount;
-	}
-
-	/* Check superblock checksum */
-	if (!ext4_superblock_csum_verify(sb, es)) {
-		ext4_msg(sb, KERN_ERR, "VFS: Found ext4 filesystem with "
-			 "invalid superblock checksum.  Run e2fsck?");
-		ret = -EFSBADCRC;
+	err = ext4_init_metadata_csum(sb, es);
+	if (err)
 		goto failed_mount;
-	}
-
-	/* Precompute checksum seed for all metadata */
-	if (ext4_has_feature_csum_seed(sb))
-		sbi->s_csum_seed = le32_to_cpu(es->s_checksum_seed);
-	else if (ext4_has_metadata_csum(sb) || ext4_has_feature_ea_inode(sb))
-		sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
-					       sizeof(es->s_uuid));
 
 	ext4_set_def_opts(sb, es);