reiserfs: use open_bdev_excl

Use the proper helper to open a blockdevice by name for filesystem use,
this makes sure it's properly claimed (also added for open-by-number) and
gets rid of the struct file abuse.

Tested by mounting a reiserfs filesystem with external journal.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jeff Mahoney <jeffm@suse.com>
Acked-by: Edward Shishkin <edward.shishkin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/journal.c

@@ -2574,11 +2574,9 @@ static int release_journal_dev(struct super_block *super,
 
 	result = 0;
 
-	if (journal->j_dev_file != NULL) {
-		result = filp_close(journal->j_dev_file, NULL);
-		journal->j_dev_file = NULL;
-		journal->j_dev_bd = NULL;
-	} else if (journal->j_dev_bd != NULL) {
+	if (journal->j_dev_bd != NULL) {
+		if (journal->j_dev_bd->bd_dev != super->s_dev)
+			bd_release(journal->j_dev_bd);
 		result = blkdev_put(journal->j_dev_bd);
 		journal->j_dev_bd = NULL;
 	}
@@ -2603,7 +2601,6 @@ static int journal_init_dev(struct super_block *super,
 	result = 0;
 
 	journal->j_dev_bd = NULL;
-	journal->j_dev_file = NULL;
 	jdev = SB_ONDISK_JOURNAL_DEVICE(super) ?
 	    new_decode_dev(SB_ONDISK_JOURNAL_DEVICE(super)) : super->s_dev;
 
@@ -2620,35 +2617,34 @@ static int journal_init_dev(struct super_block *super,
 					 "cannot init journal device '%s': %i",
 					 __bdevname(jdev, b), result);
 			return result;
-		} else if (jdev != super->s_dev)
-			set_blocksize(journal->j_dev_bd, super->s_blocksize);
-		return 0;
+		} else if (jdev != super->s_dev) {
+			result = bd_claim(journal->j_dev_bd, journal);
+			if (result) {
+				blkdev_put(journal->j_dev_bd);
+				return result;
 			}
 
-	journal->j_dev_file = filp_open(jdev_name, 0, 0);
-	if (!IS_ERR(journal->j_dev_file)) {
-		struct inode *jdev_inode = journal->j_dev_file->f_mapping->host;
-		if (!S_ISBLK(jdev_inode->i_mode)) {
-			reiserfs_warning(super, "journal_init_dev: '%s' is "
-					 "not a block device", jdev_name);
-			result = -ENOTBLK;
-			release_journal_dev(super, journal);
-		} else {
-			/* ok */
-			journal->j_dev_bd = I_BDEV(jdev_inode);
 			set_blocksize(journal->j_dev_bd, super->s_blocksize);
-			reiserfs_info(super,
-				      "journal_init_dev: journal device: %s\n",
-				      bdevname(journal->j_dev_bd, b));
 		}
-	} else {
-		result = PTR_ERR(journal->j_dev_file);
-		journal->j_dev_file = NULL;
+
+		return 0;
+	}
+
+	journal->j_dev_bd = open_bdev_excl(jdev_name, 0, journal);
+	if (IS_ERR(journal->j_dev_bd)) {
+		result = PTR_ERR(journal->j_dev_bd);
+		journal->j_dev_bd = NULL;
 		reiserfs_warning(super,
 				 "journal_init_dev: Cannot open '%s': %i",
 				 jdev_name, result);
-	}
 		return result;
+	}
+
+	set_blocksize(journal->j_dev_bd, super->s_blocksize);
+	reiserfs_info(super,
+		      "journal_init_dev: journal device: %s\n",
+		      bdevname(journal->j_dev_bd, b));
+	return 0;
 }
 
 /**

include/linux/reiserfs_fs_sb.h

@@ -177,7 +177,6 @@ struct reiserfs_journal {
 	struct reiserfs_journal_cnode *j_last;	/* newest journal block */
 	struct reiserfs_journal_cnode *j_first;	/*  oldest journal block.  start here for traverse */
 
-	struct file *j_dev_file;
 	struct block_device *j_dev_bd;
 	int j_1st_reserved_block;	/* first block on s_dev of reserved area journal */