[PATCH 11/12] ext4: cleanup ext4_get_dev_journal() and ext4_get_journal()

Zhang Yi
2023-07-04T13:44:21Z

From: Zhang Yi <yi.zhang@huawei.com>

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: Zhang Yi <yi.zhang@huawei.com>
---
fs/ext4/super.c | 109 ++++++++++++++++++++++--------------------------
1 file changed, 49 insertions(+), 60 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index ce2e02b139af..25ae536a370f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -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
*/
@@ -5780,14 +5760,14 @@ 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;
}

@@ -5819,9 +5799,6 @@ 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;
@@ -5838,25 +5815,25 @@ 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_dev(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);
@@ -5869,7 +5846,8 @@ 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;
@@ -5879,56 +5857,67 @@ 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");
- brelse(bh);
- goto out_bdev;
+ goto out_bh;
}

- len = ext4_blocks_count(es);
- start = sb_block + 1;
- brelse(bh); /* we're done with the superblock */
+ brelse(bh);
+ *j_start = sb_block + 1;
+ *j_len = ext4_blocks_count(es);
+ return bdev;
+
+out_bh:
+ brelse(bh);
+out_bdev:
+ blkdev_put(bdev, sb);
+ return NULL;
+}
+
+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_dev(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;
}

--
2.39.2