Re: [PATCH v5 4/9] btrfs: don't advance offset for compressed bios in btrfs_csum_one_bio()

Josef Bacik
2020-08-24T19:18:08Z

On 8/21/20 3:38 AM, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
>
> btrfs_csum_one_bio() loops over each filesystem block in the bio while
> keeping a cursor of its current logical position in the file in order to
> look up the ordered extent to add the checksums to. However, this
> doesn't make much sense for compressed extents, as a sector on disk does
> not correspond to a sector of decompressed file data. It happens to work
> because 1) the compressed bio always covers one ordered extent and 2)
> the size of the bio is always less than the size of the ordered extent.
> However, the second point will not always be true for encoded writes.
>
> Let's add a boolean parameter to btrfs_csum_one_bio() to indicate that
> it can assume that the bio only covers one ordered extent. Since we're
> already changing the signature, let's get rid of the contig parameter
> and make it implied by the offset parameter, similar to the change we
> recently made to btrfs_lookup_bio_sums(). Additionally, let's rename
> nr_sectors to blockcount to make it clear that it's the number of
> filesystem blocks, not the number of 512-byte sectors.
>
> Signed-off-by: Omar Sandoval <osandov@fb.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef