btrfs: sink parameter start and len to check_data_csum

For check_data_csum(), the page we're using is directly from the 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, as 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).

Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 48ebf49..8c77b1d 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2889,17 +2889,29 @@ void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
        btrfs_queue_work(wq, &ordered_extent->work);
 }
 
+/*
+ * check_data_csum - verify checksum of one sector of uncompressed data
+ * @inode:     the inode
+ * @io_bio:    btrfs_io_bio which contains the csum
+ * @icsum:     checksum index in the io_bio->csum array, size of csum_size
+ * @page:      page where is the data to be verified
+ * @pgoff:     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);
@@ -2913,8 +2925,8 @@ 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);
@@ -2955,8 +2967,7 @@ int btrfs_verify_data_csum(struct btrfs_io_bio *io_bio, u64 phy_offset,
        }
 
        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);
 }
 
 /*
@@ -7674,8 +7685,7 @@ 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)),