Commit bc74e6a3 authored by Zhang Yi's avatar Zhang Yi Committed by Theodore Ts'o
Browse files

ext4: cleanup ext4_get_dev_journal() and ext4_get_journal() 



Factor out a new helper form ext4_get_dev_journal() to get external
journal bdev and check validation of this device, drop ext4_blkdev_get()
helper, and also remove duplicate check of journal feature. It makes
ext4_get_dev_journal() more clear than before.

Signed-off-by: default avatarZhang Yi <yi.zhang@huawei.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230811063610.2980059-12-yi.zhang@huaweicloud.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 8e6cf5fb

fs/ext4/super.c

+49 −60
Original line number Diff line number Diff line
@@ -1105,26 +1105,6 @@ static const struct blk_holder_ops ext4_holder_ops = { 
	.mark_dead		= ext4_bdev_mark_dead,

};



/*

 * Open the external journal device

 */

static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)

{

	struct block_device *bdev;



	bdev = blkdev_get_by_dev(dev, BLK_OPEN_READ | BLK_OPEN_WRITE, sb,

				 &ext4_holder_ops);

	if (IS_ERR(bdev))

		goto fail;

	return bdev;



fail:

	ext4_msg(sb, KERN_ERR,

		 "failed to open journal device unknown-block(%u,%u) %ld",

		 MAJOR(dev), MINOR(dev), PTR_ERR(bdev));

	return NULL;

}



/*

 * Release the journal device

 */
@@ -5768,14 +5748,14 @@ static struct inode *ext4_get_journal_inode(struct super_block *sb, 
		ext4_msg(sb, KERN_ERR, "journal inode is deleted");

		return NULL;

	}



	ext4_debug("Journal inode found at %p: %lld bytes\n",

		  journal_inode, journal_inode->i_size);

	if (!S_ISREG(journal_inode->i_mode) || IS_ENCRYPTED(journal_inode)) {

		ext4_msg(sb, KERN_ERR, "invalid journal inode");

		iput(journal_inode);

		return NULL;

	}



	ext4_debug("Journal inode found at %p: %lld bytes\n",

		  journal_inode, journal_inode->i_size);

	return journal_inode;

}
@@ -5807,9 +5787,6 @@ static journal_t *ext4_get_journal(struct super_block *sb, 
	struct inode *journal_inode;

	journal_t *journal;



	if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))

		return NULL;



	journal_inode = ext4_get_journal_inode(sb, journal_inum);

	if (!journal_inode)

		return NULL;
@@ -5826,25 +5803,25 @@ static journal_t *ext4_get_journal(struct super_block *sb, 
	return journal;

}



static journal_t *ext4_get_dev_journal(struct super_block *sb,

				       dev_t j_dev)

static struct block_device *ext4_get_journal_blkdev(struct super_block *sb,

					dev_t j_dev, ext4_fsblk_t *j_start,

					ext4_fsblk_t *j_len)

{

	struct buffer_head *bh;

	journal_t *journal;

	ext4_fsblk_t start;

	ext4_fsblk_t len;

	struct block_device *bdev;

	int hblock, blocksize;

	ext4_fsblk_t sb_block;

	unsigned long offset;

	struct ext4_super_block *es;

	struct block_device *bdev;



	if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))

		return NULL;



	bdev = ext4_blkdev_get(j_dev, sb);

	if (bdev == NULL)

	bdev = blkdev_get_by_dev(j_dev, BLK_OPEN_READ | BLK_OPEN_WRITE, sb,

				 &ext4_holder_ops);

	if (IS_ERR(bdev)) {

		ext4_msg(sb, KERN_ERR,

			 "failed to open journal device unknown-block(%u,%u) %ld",

			 MAJOR(j_dev), MINOR(j_dev), PTR_ERR(bdev));

		return NULL;

	}



	blocksize = sb->s_blocksize;

	hblock = bdev_logical_block_size(bdev);
@@ -5857,7 +5834,8 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb, 
	sb_block = EXT4_MIN_BLOCK_SIZE / blocksize;

	offset = EXT4_MIN_BLOCK_SIZE % blocksize;

	set_blocksize(bdev, blocksize);

	if (!(bh = __bread(bdev, sb_block, blocksize))) {

	bh = __bread(bdev, sb_block, blocksize);

	if (!bh) {

		ext4_msg(sb, KERN_ERR, "couldn't read superblock of "

		       "external journal");

		goto out_bdev;
@@ -5867,56 +5845,67 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb, 
	if ((le16_to_cpu(es->s_magic) != EXT4_SUPER_MAGIC) ||

	    !(le32_to_cpu(es->s_feature_incompat) &

	      EXT4_FEATURE_INCOMPAT_JOURNAL_DEV)) {

		ext4_msg(sb, KERN_ERR, "external journal has "

					"bad superblock");

		brelse(bh);

		goto out_bdev;

		ext4_msg(sb, KERN_ERR, "external journal has bad superblock");

		goto out_bh;

	}



	if ((le32_to_cpu(es->s_feature_ro_compat) &

	     EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&

	    es->s_checksum != ext4_superblock_csum(sb, es)) {

		ext4_msg(sb, KERN_ERR, "external journal has "

				       "corrupt superblock");

		brelse(bh);

		goto out_bdev;

		ext4_msg(sb, KERN_ERR, "external journal has corrupt superblock");

		goto out_bh;

	}



	if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {

		ext4_msg(sb, KERN_ERR, "journal UUID does not match");

		goto out_bh;

	}



	*j_start = sb_block + 1;

	*j_len = ext4_blocks_count(es);

	brelse(bh);

		goto out_bdev;

	return bdev;



out_bh:

	brelse(bh);

out_bdev:

	blkdev_put(bdev, sb);

	return NULL;

}



	len = ext4_blocks_count(es);

	start = sb_block + 1;

	brelse(bh);	/* we're done with the superblock */

static journal_t *ext4_get_dev_journal(struct super_block *sb,

				       dev_t j_dev)

{

	journal_t *journal;

	ext4_fsblk_t j_start;

	ext4_fsblk_t j_len;

	struct block_device *journal_bdev;



	journal_bdev = ext4_get_journal_blkdev(sb, j_dev, &j_start, &j_len);

	if (!journal_bdev)

		return NULL;



	journal = jbd2_journal_init_dev(bdev, sb->s_bdev,

					start, len, blocksize);

	journal = jbd2_journal_init_dev(journal_bdev, sb->s_bdev, j_start,

					j_len, sb->s_blocksize);

	if (IS_ERR(journal)) {

		ext4_msg(sb, KERN_ERR, "failed to create device journal");

		goto out_bdev;

	}

	journal->j_private = sb;

	if (ext4_read_bh_lock(journal->j_sb_buffer, REQ_META | REQ_PRIO, true)) {

		ext4_msg(sb, KERN_ERR, "I/O error on journal device");

		goto out_journal;

	}

	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {

		ext4_msg(sb, KERN_ERR, "External journal has more than one "

					"user (unsupported) - %d",

			be32_to_cpu(journal->j_superblock->s_nr_users));

		goto out_journal;

	}

	EXT4_SB(sb)->s_journal_bdev = bdev;

	journal->j_private = sb;

	EXT4_SB(sb)->s_journal_bdev = journal_bdev;

	ext4_init_journal_params(sb, journal);

	return journal;



out_journal:

	jbd2_journal_destroy(journal);

out_bdev:

	blkdev_put(bdev, sb);

	blkdev_put(journal_bdev, sb);

	return NULL;

}