f2fs: add a max block check for get_data_block_bmap

This patch adds a max block check for get_data_block_bmap.

Trinity test program will send a block number as parameter into
ioctl_fibmap, which will be used in get_node_path(), when the block
number large than f2fs max blocks, it will trigger kernel bug.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Xue Liu <liuxueliu.liu@huawei.com>
[Jaegeuk Kim: fix missing condition, pointed by Chao Yu]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index d67c599..6fbfc70 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -761,6 +761,10 @@
 static int get_data_block_bmap(struct inode *inode, sector_t iblock,
 			struct buffer_head *bh_result, int create)
 {
+	/* Block number less than F2FS MAX BLOCKS */
+	if (unlikely(iblock >= max_file_size(0)))
+		return -EFBIG;
+
 	return __get_data_block(inode, iblock, bh_result, create,
 						F2FS_GET_BLOCK_BMAP);
 }