Ext3: add necessary check in case IO error happens

As we know io error may happen when the function 'sb_getblk'
is called.Add necessary check for it

The patch also fix a coding style problem.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext3/inode.c

@@ -676,6 +676,10 @@ static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
 		 * parent to disk.
 		 */
 		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
+		if (unlikely(!bh)) {
+			err = -ENOMEM;
+			goto failed;
+		}
 		branch[n].bh = bh;
 		lock_buffer(bh);
 		BUFFER_TRACE(bh, "call get_create_access");
@@ -717,7 +721,7 @@ static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
 		BUFFER_TRACE(branch[i].bh, "call journal_forget");
 		ext3_journal_forget(handle, branch[i].bh);
 	}
-	for (i = 0; i <indirect_blks; i++)
+	for (i = 0; i < indirect_blks; i++)
 		ext3_free_blocks(handle, inode, new_blocks[i], 1);
 
 	ext3_free_blocks(handle, inode, new_blocks[i], num);