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Date:   Thu, 3 Aug 2023 16:07:07 +0200
From:   Jan Kara <jack@suse.cz>
To:     Zhang Yi <yi.zhang@huaweicloud.com>
Cc:     linux-ext4@vger.kernel.org, tytso@mit.edu,
        adilger.kernel@dilger.ca, jack@suse.cz, yi.zhang@huawei.com,
        chengzhihao1@huawei.com, yukuai3@huawei.com
Subject: Re: [PATCH 01/12] jbd2: move load_superblock() dependent functions
Message-ID: <20230803140707.avrvyookvhotwrw7@quack3>
References: <20230704134233.110812-1-yi.zhang@huaweicloud.com>
 <20230704134233.110812-2-yi.zhang@huaweicloud.com>
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In-Reply-To: <20230704134233.110812-2-yi.zhang@huaweicloud.com>
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On Tue 04-07-23 21:42:22, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
> 
> Moving load_superblock() dependent functions before
> journal_init_common(), just preparing for moving the call to
> load_superblock() from jbd2_journal_load() and jbd2_journal_wipe() to
> journal_init_common(), no functional changes.
> 
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>

I'd just slightly rephrase the changelog:

Move load_superblock() declaration and the functions it calls before
journal_init_common(). This is a preparation for moving a call to
load_superblock() from jbd2_journal_load() and jbd2_journal_wipe() to
journal_init_common(). No functional changes.

Otherwise the patch looks good. Feel free to add:

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

								Honza

> ---
>  fs/jbd2/journal.c | 337 +++++++++++++++++++++++-----------------------
>  1 file changed, 168 insertions(+), 169 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index fbce16fedaa4..48c44c7fccf4 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -1336,6 +1336,174 @@ static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink,
>  	return count;
>  }
>  
> +/*
> + * If the journal init or create aborts, we need to mark the journal
> + * superblock as being NULL to prevent the journal destroy from writing
> + * back a bogus superblock.
> + */
> +static void journal_fail_superblock(journal_t *journal)
> +{
> +	struct buffer_head *bh = journal->j_sb_buffer;
> +	brelse(bh);
> +	journal->j_sb_buffer = NULL;
> +}
> +
> +/*
> + * Read the superblock for a given journal, performing initial
> + * validation of the format.
> + */
> +static int journal_get_superblock(journal_t *journal)
> +{
> +	struct buffer_head *bh;
> +	journal_superblock_t *sb;
> +	int err;
> +
> +	bh = journal->j_sb_buffer;
> +
> +	J_ASSERT(bh != NULL);
> +	if (buffer_verified(bh))
> +		return 0;
> +
> +	err = bh_read(bh, 0);
> +	if (err < 0) {
> +		printk(KERN_ERR
> +			"JBD2: IO error reading journal superblock\n");
> +		goto out;
> +	}
> +
> +	sb = journal->j_superblock;
> +
> +	err = -EINVAL;
> +
> +	if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
> +	    sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
> +		printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
> +		goto out;
> +	}
> +
> +	if (be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V1 &&
> +	    be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V2) {
> +		printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
> +		goto out;
> +	}
> +
> +	if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
> +		printk(KERN_WARNING "JBD2: journal file too short\n");
> +		goto out;
> +	}
> +
> +	if (be32_to_cpu(sb->s_first) == 0 ||
> +	    be32_to_cpu(sb->s_first) >= journal->j_total_len) {
> +		printk(KERN_WARNING
> +			"JBD2: Invalid start block of journal: %u\n",
> +			be32_to_cpu(sb->s_first));
> +		goto out;
> +	}
> +
> +	if (jbd2_has_feature_csum2(journal) &&
> +	    jbd2_has_feature_csum3(journal)) {
> +		/* Can't have checksum v2 and v3 at the same time! */
> +		printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
> +		       "at the same time!\n");
> +		goto out;
> +	}
> +
> +	if (jbd2_journal_has_csum_v2or3_feature(journal) &&
> +	    jbd2_has_feature_checksum(journal)) {
> +		/* Can't have checksum v1 and v2 on at the same time! */
> +		printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
> +		       "at the same time!\n");
> +		goto out;
> +	}
> +
> +	if (!jbd2_verify_csum_type(journal, sb)) {
> +		printk(KERN_ERR "JBD2: Unknown checksum type\n");
> +		goto out;
> +	}
> +
> +	/* Load the checksum driver */
> +	if (jbd2_journal_has_csum_v2or3_feature(journal)) {
> +		journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
> +		if (IS_ERR(journal->j_chksum_driver)) {
> +			printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
> +			err = PTR_ERR(journal->j_chksum_driver);
> +			journal->j_chksum_driver = NULL;
> +			goto out;
> +		}
> +		/* Check superblock checksum */
> +		if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
> +			printk(KERN_ERR "JBD2: journal checksum error\n");
> +			err = -EFSBADCRC;
> +			goto out;
> +		}
> +	}
> +	set_buffer_verified(bh);
> +	return 0;
> +
> +out:
> +	journal_fail_superblock(journal);
> +	return err;
> +}
> +
> +static int journal_revoke_records_per_block(journal_t *journal)
> +{
> +	int record_size;
> +	int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t);
> +
> +	if (jbd2_has_feature_64bit(journal))
> +		record_size = 8;
> +	else
> +		record_size = 4;
> +
> +	if (jbd2_journal_has_csum_v2or3(journal))
> +		space -= sizeof(struct jbd2_journal_block_tail);
> +	return space / record_size;
> +}
> +
> +/*
> + * Load the on-disk journal superblock and read the key fields into the
> + * journal_t.
> + */
> +static int load_superblock(journal_t *journal)
> +{
> +	int err;
> +	journal_superblock_t *sb;
> +	int num_fc_blocks;
> +
> +	err = journal_get_superblock(journal);
> +	if (err)
> +		return err;
> +
> +	sb = journal->j_superblock;
> +
> +	journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
> +	journal->j_tail = be32_to_cpu(sb->s_start);
> +	journal->j_first = be32_to_cpu(sb->s_first);
> +	journal->j_errno = be32_to_cpu(sb->s_errno);
> +	journal->j_last = be32_to_cpu(sb->s_maxlen);
> +
> +	if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
> +		journal->j_total_len = be32_to_cpu(sb->s_maxlen);
> +	/* Precompute checksum seed for all metadata */
> +	if (jbd2_journal_has_csum_v2or3(journal))
> +		journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
> +						   sizeof(sb->s_uuid));
> +	journal->j_revoke_records_per_block =
> +				journal_revoke_records_per_block(journal);
> +
> +	if (jbd2_has_feature_fast_commit(journal)) {
> +		journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
> +		num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
> +		if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
> +			journal->j_last = journal->j_fc_last - num_fc_blocks;
> +		journal->j_fc_first = journal->j_last + 1;
> +		journal->j_fc_off = 0;
> +	}
> +
> +	return 0;
> +}
> +
> +
>  /*
>   * Management for journal control blocks: functions to create and
>   * destroy journal_t structures, and to initialise and read existing
> @@ -1521,18 +1689,6 @@ journal_t *jbd2_journal_init_inode(struct inode *inode)
>  	return journal;
>  }
>  
> -/*
> - * If the journal init or create aborts, we need to mark the journal
> - * superblock as being NULL to prevent the journal destroy from writing
> - * back a bogus superblock.
> - */
> -static void journal_fail_superblock(journal_t *journal)
> -{
> -	struct buffer_head *bh = journal->j_sb_buffer;
> -	brelse(bh);
> -	journal->j_sb_buffer = NULL;
> -}
> -
>  /*
>   * Given a journal_t structure, initialise the various fields for
>   * startup of a new journaling session.  We use this both when creating
> @@ -1889,163 +2045,6 @@ void jbd2_journal_update_sb_errno(journal_t *journal)
>  }
>  EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
>  
> -static int journal_revoke_records_per_block(journal_t *journal)
> -{
> -	int record_size;
> -	int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t);
> -
> -	if (jbd2_has_feature_64bit(journal))
> -		record_size = 8;
> -	else
> -		record_size = 4;
> -
> -	if (jbd2_journal_has_csum_v2or3(journal))
> -		space -= sizeof(struct jbd2_journal_block_tail);
> -	return space / record_size;
> -}
> -
> -/*
> - * Read the superblock for a given journal, performing initial
> - * validation of the format.
> - */
> -static int journal_get_superblock(journal_t *journal)
> -{
> -	struct buffer_head *bh;
> -	journal_superblock_t *sb;
> -	int err;
> -
> -	bh = journal->j_sb_buffer;
> -
> -	J_ASSERT(bh != NULL);
> -	if (buffer_verified(bh))
> -		return 0;
> -
> -	err = bh_read(bh, 0);
> -	if (err < 0) {
> -		printk(KERN_ERR
> -			"JBD2: IO error reading journal superblock\n");
> -		goto out;
> -	}
> -
> -	sb = journal->j_superblock;
> -
> -	err = -EINVAL;
> -
> -	if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
> -	    sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
> -		printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
> -		goto out;
> -	}
> -
> -	if (be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V1 &&
> -	    be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V2) {
> -		printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
> -		goto out;
> -	}
> -
> -	if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
> -		printk(KERN_WARNING "JBD2: journal file too short\n");
> -		goto out;
> -	}
> -
> -	if (be32_to_cpu(sb->s_first) == 0 ||
> -	    be32_to_cpu(sb->s_first) >= journal->j_total_len) {
> -		printk(KERN_WARNING
> -			"JBD2: Invalid start block of journal: %u\n",
> -			be32_to_cpu(sb->s_first));
> -		goto out;
> -	}
> -
> -	if (jbd2_has_feature_csum2(journal) &&
> -	    jbd2_has_feature_csum3(journal)) {
> -		/* Can't have checksum v2 and v3 at the same time! */
> -		printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
> -		       "at the same time!\n");
> -		goto out;
> -	}
> -
> -	if (jbd2_journal_has_csum_v2or3_feature(journal) &&
> -	    jbd2_has_feature_checksum(journal)) {
> -		/* Can't have checksum v1 and v2 on at the same time! */
> -		printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
> -		       "at the same time!\n");
> -		goto out;
> -	}
> -
> -	if (!jbd2_verify_csum_type(journal, sb)) {
> -		printk(KERN_ERR "JBD2: Unknown checksum type\n");
> -		goto out;
> -	}
> -
> -	/* Load the checksum driver */
> -	if (jbd2_journal_has_csum_v2or3_feature(journal)) {
> -		journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
> -		if (IS_ERR(journal->j_chksum_driver)) {
> -			printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
> -			err = PTR_ERR(journal->j_chksum_driver);
> -			journal->j_chksum_driver = NULL;
> -			goto out;
> -		}
> -		/* Check superblock checksum */
> -		if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
> -			printk(KERN_ERR "JBD2: journal checksum error\n");
> -			err = -EFSBADCRC;
> -			goto out;
> -		}
> -	}
> -	set_buffer_verified(bh);
> -	return 0;
> -
> -out:
> -	journal_fail_superblock(journal);
> -	return err;
> -}
> -
> -/*
> - * Load the on-disk journal superblock and read the key fields into the
> - * journal_t.
> - */
> -
> -static int load_superblock(journal_t *journal)
> -{
> -	int err;
> -	journal_superblock_t *sb;
> -	int num_fc_blocks;
> -
> -	err = journal_get_superblock(journal);
> -	if (err)
> -		return err;
> -
> -	sb = journal->j_superblock;
> -
> -	journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
> -	journal->j_tail = be32_to_cpu(sb->s_start);
> -	journal->j_first = be32_to_cpu(sb->s_first);
> -	journal->j_errno = be32_to_cpu(sb->s_errno);
> -	journal->j_last = be32_to_cpu(sb->s_maxlen);
> -
> -	if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
> -		journal->j_total_len = be32_to_cpu(sb->s_maxlen);
> -	/* Precompute checksum seed for all metadata */
> -	if (jbd2_journal_has_csum_v2or3(journal))
> -		journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
> -						   sizeof(sb->s_uuid));
> -	journal->j_revoke_records_per_block =
> -				journal_revoke_records_per_block(journal);
> -
> -	if (jbd2_has_feature_fast_commit(journal)) {
> -		journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
> -		num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
> -		if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
> -			journal->j_last = journal->j_fc_last - num_fc_blocks;
> -		journal->j_fc_first = journal->j_last + 1;
> -		journal->j_fc_off = 0;
> -	}
> -
> -	return 0;
> -}
> -
> -
>  /**
>   * jbd2_journal_load() - Read journal from disk.
>   * @journal: Journal to act on.
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR