jbd2: fix /proc/fs/jbd2/<dev> when using an external journal

In jbd2_journal_init_dev(), we need make sure the journal structure is
fully initialzied before calling jbd2_stats_proc_init().

Reviewed-by: Andreas Dilger <andreas.dilger@oracle.com>
Signed-off-by: yangsheng <sheng.yang@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/jbd2/journal.c

@@ -899,6 +899,14 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev,
 
 	/* journal descriptor can store up to n blocks -bzzz */
 	journal->j_blocksize = blocksize;
+	journal->j_dev = bdev;
+	journal->j_fs_dev = fs_dev;
+	journal->j_blk_offset = start;
+	journal->j_maxlen = len;
+	bdevname(journal->j_dev, journal->j_devname);
+	p = journal->j_devname;
+	while ((p = strchr(p, '/')))
+		*p = '!';
 	jbd2_stats_proc_init(journal);
 	n = journal->j_blocksize / sizeof(journal_block_tag_t);
 	journal->j_wbufsize = n;
@@ -908,14 +916,6 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev,
 			__func__);
 		goto out_err;
 	}
-	journal->j_dev = bdev;
-	journal->j_fs_dev = fs_dev;
-	journal->j_blk_offset = start;
-	journal->j_maxlen = len;
-	bdevname(journal->j_dev, journal->j_devname);
-	p = journal->j_devname;
-	while ((p = strchr(p, '/')))
-		*p = '!';
 
 	bh = __getblk(journal->j_dev, start, journal->j_blocksize);
 	if (!bh) {