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>

fs/ocfs2/buffer_head_io.c

@@ -79,7 +79,7 @@ int ocfs2_write_block(struct ocfs2_super *osb, struct buffer_head *bh,
 		 * 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 @@ int ocfs2_read_blocks(struct ocfs2_super *osb, u64 block, int nr,
 				 * 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 @@ int ocfs2_write_super_or_backup(struct ocfs2_super *osb,
 
 	if (!buffer_uptodate(bh)) {
 		ret = -EIO;
-		brelse(bh);
+		put_bh(bh);
 	}
 
 out:

fs/ocfs2/resize.c

@@ -257,7 +257,6 @@ static void ocfs2_update_super_and_backups(struct inode *inode,
 		ret = update_backups(inode, clusters, super_bh->b_data);
 
 out:
-	if (super_bh)
 	brelse(super_bh);
 	if (ret)
 		printk(KERN_WARNING "ocfs2: Failed to update super blocks on %s"
@@ -380,10 +379,7 @@ int ocfs2_group_extend(struct inode * inode, int new_clusters)
 out_commit:
 	ocfs2_commit_trans(osb, handle);
 out_unlock:
-	if (group_bh)
 	brelse(group_bh);
-
-	if (main_bm_bh)
 	brelse(main_bm_bh);
 
 	ocfs2_inode_unlock(main_bm_inode, 1);
@@ -623,10 +619,7 @@ int ocfs2_group_add(struct inode *inode, struct ocfs2_new_group_input *input)
 out_commit:
 	ocfs2_commit_trans(osb, handle);
 out_unlock:
-	if (group_bh)
 	brelse(group_bh);
-
-	if (main_bm_bh)
 	brelse(main_bm_bh);
 
 	ocfs2_inode_unlock(main_bm_inode, 1);