Btrfs: Fix verify_parent_transid

It was incorrectly clearing the up to date flag on the buffer even
when the buffer properly verified.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index e3547a992d5c..964ec1622d66 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2647,6 +2647,8 @@ static inline struct page *extent_buffer_page(struct extent_buffer *eb,
                 return eb->first_page;
         i += eb->start >> PAGE_CACHE_SHIFT;
         mapping = eb->first_page->mapping;
+        if (!mapping)
+                return NULL;
         read_lock_irq(&mapping->tree_lock);
         p = radix_tree_lookup(&mapping->page_tree, i);
         read_unlock_irq(&mapping->tree_lock);
@@ -2908,7 +2910,8 @@ int clear_extent_buffer_uptodate(struct extent_io_tree *tree,
                               GFP_NOFS);
         for (i = 0; i < num_pages; i++) {
                 page = extent_buffer_page(eb, i);
-                ClearPageUptodate(page);
+                if (page)
+                        ClearPageUptodate(page);
         }
         return 0;
 }