ocfs2: clean up bh null checks

If we know a buffer_head is non-null, then brelse() is unnecessary and
put_bh() can be used instead. Also, an explicit check for NULL is
unnecessary when using brelse(). This patch only covers buffer_head_io.c and
resize.c, which have recently added code which exhibits this problem.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
index 31aa61d..f136639 100644
--- a/fs/ocfs2/buffer_head_io.c
+++ b/fs/ocfs2/buffer_head_io.c
@@ -79,7 +79,7 @@
 		 * information for this bh as it's not marked locally
 		 * uptodate. */
 		ret = -EIO;
-		brelse(bh);
+		put_bh(bh);
 	}
 
 	mutex_unlock(&OCFS2_I(inode)->ip_io_mutex);
@@ -256,7 +256,7 @@
 				 * for this bh as it's not marked locally
 				 * uptodate. */
 				status = -EIO;
-				brelse(bh);
+				put_bh(bh);
 				bhs[i] = NULL;
 				continue;
 			}
@@ -334,7 +334,7 @@
 
 	if (!buffer_uptodate(bh)) {
 		ret = -EIO;
-		brelse(bh);
+		put_bh(bh);
 	}
 
 out: