Commit a89ce08c authored by Christoph Hellwig's avatar Christoph Hellwig Committed by David Sterba
Browse files

btrfs: factor out a btrfs_csum_ptr helper 



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

Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 97861cd1

fs/btrfs/ctree.h

+8 −0
Original line number Diff line number Diff line
@@ -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(const 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 checksummed and figure out how many leaves

 * it would require to store the csums for that many bytes.

fs/btrfs/inode.c

+3 −10
Original line number Diff line number Diff line
@@ -3371,15 +3371,12 @@ 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;
@@ -8020,12 +8017,8 @@ 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);