fs: use block_device name vsprintf helper

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index ca181e8..081dff0 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -764,13 +764,11 @@
 
 static void warn_dirty_buffer(struct buffer_head *bh)
 {
-	char b[BDEVNAME_SIZE];
-
 	printk(KERN_WARNING
-	       "JBD2: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). "
+	       "JBD2: Spotted dirty metadata buffer (dev = %pg, blocknr = %llu). "
 	       "There's a risk of filesystem corruption in case of system "
 	       "crash.\n",
-	       bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
+	       bh->b_bdev, (unsigned long long)bh->b_blocknr);
 }
 
 /* Call t_frozen trigger and copy buffer data into jh->b_frozen_data. */