f2fs: return early when trying to read null nid

If get_node_page() gets zero nid, we can return early without getting a wrong
page. For example, get_dnode_of_data() can try to do that.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 341de5d2353b3a3fb397d576d1c482d665ee023c..929265d20c3276490cc2a47ddab76873febbffc5 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1059,6 +1059,10 @@ struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid)
 {
        struct page *page;
        int err;
+
+       if (!nid)
+               return ERR_PTR(-ENOENT);
+       f2fs_bug_on(sbi, check_nid_range(sbi, nid));
 repeat:
        page = grab_cache_page(NODE_MAPPING(sbi), nid);
        if (!page)