From a26663e7a2f456b8111de0135394c04c72831930 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 3 Nov 2020 21:30:47 +0800 Subject: [PATCH] btrfs: make csum_tree_block() handle node smaller than page For subpage size support, metadata blocks of nodesize are smaller than one page and this needs to be handled when calculating the checksum. The checksummed start and length need to be adjusted but only for the first page: - start is simply offset in the page - length is nodesize (subpage) or PAGE_SIZE for all other cases Reviewed-by: Nikolay Borisov Signed-off-by: Goldwyn Rodrigues Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index abc929a47d4b8..1c8c94dbe9846 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -212,15 +212,16 @@ 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 first_page_part = min_t(u32, PAGE_SIZE, fs_info->nodesize); SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); char *kaddr; int i; shash->tfm = fs_info->csum_shash; crypto_shash_init(shash); - kaddr = page_address(buf->pages[0]); + kaddr = page_address(buf->pages[0]) + offset_in_page(buf->start); crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE, - PAGE_SIZE - BTRFS_CSUM_SIZE); + first_page_part - BTRFS_CSUM_SIZE); for (i = 1; i < num_pages; i++) { kaddr = page_address(buf->pages[i]); -- 2.30.2