Btrfs: zero page past end of inline file items

When btrfs_get_extent is reading inline file items for readpage, it needs to copy the inline extent into the page. If the inline extent doesn't cover all of the page, that means there is a hole in the file, or that our file is smaller than one page. readpage does zeroing for the case where the file is smaller than one page, but nobody is currently zeroing for the case where there is a hole after the inline item. This commit changes btrfs_get_extent to zero fill the page past the end of the inline item. Signed-off-by: Chris Mason <[email protected]>
tiwai · Sep 11, 2009 · 93c82d5 · 93c82d5
1 parent 50a9b21
commit 93c82d5
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
@@ -4233,6 +4233,11 @@ struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
 				map = kmap(page);
 				read_extent_buffer(leaf, map + pg_offset, ptr,
 						   copy_size);
+				if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
+					memset(map + pg_offset + copy_size, 0,
+					       PAGE_CACHE_SIZE - pg_offset -
+					       copy_size);
+				}
 				kunmap(page);
 			}
 			flush_dcache_page(page);