+ /* Warn if metadata_csum and gdt_csum are both set. */
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+ EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
+ ext4_warning(sb, KERN_INFO "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.");
+ silent = 1;
+ goto cantfind_ext4;
+ }
+
+ /* Load the checksum driver */
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+ 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?");
+ silent = 1;
+ goto cantfind_ext4;
+ }
+
+ /* Precompute checksum seed for all metadata */
+ if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+ sbi->s_csum_seed = ext4_chksum(sbi, ~0, es->s_uuid,
+ sizeof(es->s_uuid));
+