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authorDavid Sterba2021-07-28 18:00:24 +0200
committerDavid Sterba2021-07-29 13:01:04 +0200
commit7280305eb57dd32735f795ed4ee679bf9854f9d0 (patch)
treef3b169d1e5110807a30e7b1c4ce39b5db4a45c5c
parentb2a616676839e2a6b02c8e40be7f886f882ed194 (diff)
btrfs: calculate number of eb pages properly in csum_tree_block
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 <gustavo@embeddedor.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/disk-io.c2
1 files changed, 1 insertions, 1 deletions
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;