From 7280305eb57dd32735f795ed4ee679bf9854f9d0 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Wed, 28 Jul 2021 18:00:24 +0200 Subject: btrfs: calculate number of eb pages properly in csum_tree_block MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Building with -Warray-bounds on systems with 64K pages there's a warning: fs/btrfs/disk-io.c: In function ‘csum_tree_block’: fs/btrfs/disk-io.c:226:34: warning: array subscript 1 is above array bounds of ‘struct page *[1]’ [-Warray-bounds] 226 | kaddr = page_address(buf->pages[i]); | ~~~~~~~~~~^~~ ./include/linux/mm.h:1630:48: note: in definition of macro ‘page_address’ 1630 | #define page_address(page) lowmem_page_address(page) | ^~~~ In file included from fs/btrfs/ctree.h:32, from fs/btrfs/disk-io.c:23: fs/btrfs/extent_io.h:98:15: note: while referencing ‘pages’ 98 | struct page *pages[1]; | ^~~~~ The compiler has no way to know that in that case the nodesize is exactly PAGE_SIZE, so the resulting number of pages will be correct (1). Let's use num_extent_pages that makes the case nodesize == PAGE_SIZE explicitly 1. Reported-by: Gustavo A. R. Silva Reviewed-by: Qu Wenruo Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index b117dd3b8172..a59ab7b9aea0 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -209,7 +209,7 @@ void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, static void csum_tree_block(struct extent_buffer *buf, u8 *result) { struct btrfs_fs_info *fs_info = buf->fs_info; - const int num_pages = fs_info->nodesize >> PAGE_SHIFT; + const int num_pages = num_extent_pages(buf); const int first_page_part = min_t(u32, PAGE_SIZE, fs_info->nodesize); SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); char *kaddr; -- cgit v1.2.3-59-g8ed1b