f2fs: fix missing up_read

This patch fixes missing up_read call.

Fixes: c9b60788 ("f2fs: fix to do sanity check with block address in main area")
Cc: <stable@vger.kernel.org> # 4.19+
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/node.c

@@ -1541,8 +1541,10 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted,
 	}
 
 	if (__is_valid_data_blkaddr(ni.blk_addr) &&
-		!f2fs_is_valid_blkaddr(sbi, ni.blk_addr, DATA_GENERIC))
+		!f2fs_is_valid_blkaddr(sbi, ni.blk_addr, DATA_GENERIC)) {
+		up_read(&sbi->node_write);
 		goto redirty_out;
+	}
 
 	if (atomic && !test_opt(sbi, NOBARRIER))
 		fio.op_flags |= REQ_PREFLUSH | REQ_FUA;