[PATCH 6/8] btrfs: factor out a btrfs_csum_ptr helper

Christoph Hellwig
2022-05-22T11:48:26Z

Add a helper to find the csum for a byte offset into the csum buffer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
fs/btrfs/ctree.h | 8 ++++++++
fs/btrfs/inode.c | 13 +++----------
2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8dd7d36b83ecb..d982ea62c521b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2733,6 +2733,14 @@ int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
enum btrfs_inline_ref_type is_data);
u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset);

+static inline u8 *btrfs_csum_ptr(struct btrfs_fs_info *fs_info, u8 *csums,
+ u64 offset)
+{
+ u64 offset_in_sectors = offset >> fs_info->sectorsize_bits;
+
+ return csums + offset_in_sectors * fs_info->csum_size;
+}
+
/*
* Take the number of bytes to be checksummmed and figure out how many leaves
* it would require to store the csums for that many bytes.
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e4acdec9ffc69..095632977a798 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3369,15 +3369,12 @@ static int check_data_csum(struct inode *inode, struct btrfs_bio *bbio,
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
u32 len = fs_info->sectorsize;
- const u32 csum_size = fs_info->csum_size;
- unsigned int offset_sectors;
u8 *csum_expected;
u8 csum[BTRFS_CSUM_SIZE];

ASSERT(pgoff + len <= PAGE_SIZE);

- offset_sectors = bio_offset >> fs_info->sectorsize_bits;
- csum_expected = ((u8 *)bbio->csum) + offset_sectors * csum_size;
+ csum_expected = btrfs_csum_ptr(fs_info, bbio->csum, bio_offset);

if (btrfs_check_sector_csum(fs_info, page, pgoff, csum, csum_expected))
goto zeroit;
@@ -8007,12 +8004,8 @@ static inline blk_status_t btrfs_submit_dio_bio(struct bio *bio,
if (ret)
goto err;
} else {
- u64 csum_offset;
-
- csum_offset = file_offset - dip->file_offset;
- csum_offset >>= fs_info->sectorsize_bits;
- csum_offset *= fs_info->csum_size;
- btrfs_bio(bio)->csum = dip->csums + csum_offset;
+ btrfs_bio(bio)->csum = btrfs_csum_ptr(fs_info, dip->csums,
+ file_offset - dip->file_offset);
}
map:
ret = btrfs_map_bio(fs_info, bio, 0);
--
2.30.2