Re: [PATCH 08/13] ext4: factor out ext4_handle_csum()

[Jan Kara <jack@suse.cz>]

On Tue 30-08-22 20:04:06, Jason Yan wrote:
> Factor out ext4_handle_csum(). No functional change.
> 
> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> ---
>  fs/ext4/super.c | 83 +++++++++++++++++++++++++++----------------------
>  1 file changed, 46 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 9ee27472b802..96cf23787bba 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -4563,6 +4563,50 @@ static int ext4_encoding_init(struct super_block *sb, struct ext4_super_block *e
>  	return 0;
>  }
>  
> +static int ext4_handle_csum(struct super_block *sb, struct ext4_super_block *es)

I'd rather call this function like ext4_init_metadata_csum().
ext4_handle_csum() seems to vague to me.

Otherwise the patch looks good to me. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> +{
> +	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;
> @@ -4632,44 +4676,9 @@ 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_handle_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);
>  
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR