[PATCH 12/17] btrfs: remove the unnecessary parameter @start and @len for check_data_csum()

Qu Wenruo
2020-09-08T07:53:29Z

For check_data_csum(), the page we're using is directly from inode
mapping, thus it has valid page_offset().

We can use (page_offset() + pg_off) to replace @start parameter
completely, while the @len should always be sectorsize.

Since we're here, also add some comment, since there are quite some
confusion in words like start/offset, without explaining whether it's
file_offset or logical bytenr.

This should not affect the existing behavior, as for current sectorsize
== PAGE_SIZE case, @pgoff should always be 0, and len is always
PAGE_SIZE (or sectorsize from the dio read path).

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/inode.c | 27 +++++++++++++++++++--------
1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 9570458aa847..078735aa0f68 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2793,17 +2793,30 @@ void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
btrfs_queue_work(wq, &ordered_extent->work);
}

+/*
+ * Verify the checksum of one sector of uncompressed data.
+ *
+ * @inode: The inode.
+ * @io_bio: The btrfs_io_bio which contains the csum.
+ * @icsum: The csum offset (by number of sectors).
+ * @page: The page where the data will be written to.
+ * @pgoff: The offset inside the page.
+ *
+ * The length of such check is always one sector size.
+ */
static int check_data_csum(struct inode *inode, struct btrfs_io_bio *io_bio,
- int icsum, struct page *page, int pgoff, u64 start,
- size_t len)
+ int icsum, struct page *page, int pgoff)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
char *kaddr;
+ u32 len = fs_info->sectorsize;
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
u8 *csum_expected;
u8 csum[BTRFS_CSUM_SIZE];

+ ASSERT(pgoff + len <= PAGE_SIZE);
+
csum_expected = ((u8 *)io_bio->csum) + icsum * csum_size;

kaddr = kmap_atomic(page);
@@ -2817,8 +2830,8 @@ static int check_data_csum(struct inode *inode, struct btrfs_io_bio *io_bio,
kunmap_atomic(kaddr);
return 0;
zeroit:
- btrfs_print_data_csum_error(BTRFS_I(inode), start, csum, csum_expected,
- io_bio->mirror_num);
+ btrfs_print_data_csum_error(BTRFS_I(inode), page_offset(page) + pgoff,
+ csum, csum_expected, io_bio->mirror_num);
if (io_bio->device)
btrfs_dev_stat_inc_and_print(io_bio->device,
BTRFS_DEV_STAT_CORRUPTION_ERRS);
@@ -2857,8 +2870,7 @@ static int btrfs_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
}

phy_offset >>= inode->i_sb->s_blocksize_bits;
- return check_data_csum(inode, io_bio, phy_offset, page, offset, start,
- (size_t)(end - start + 1));
+ return check_data_csum(inode, io_bio, phy_offset, page, offset);
}

/*
@@ -7545,8 +7557,7 @@ static blk_status_t btrfs_check_read_dio_bio(struct inode *inode,
ASSERT(pgoff < PAGE_SIZE);
if (uptodate &&
(!csum || !check_data_csum(inode, io_bio, icsum,
- bvec.bv_page, pgoff,
- start, sectorsize))) {
+ bvec.bv_page, pgoff))) {
clean_io_failure(fs_info, failure_tree, io_tree,
start, bvec.bv_page,
btrfs_ino(BTRFS_I(inode)),
--
2.28.0