On 2024-03-17 09:32:47, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> As a minor space optimization, don't store trailing zeroes of merkle
> tree blocks to reduce space consumption and copying overhead. This
> really only affects the rightmost blocks at each level of the tree.
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Looks good to me:
Reviewed-by: Andrey Albershteyn <aalbersh@xxxxxxxxxx>
> ---
> fs/xfs/xfs_verity.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
>
> diff --git a/fs/xfs/xfs_verity.c b/fs/xfs/xfs_verity.c
> index 32891ae42c47..abd95bc1ba6e 100644
> --- a/fs/xfs/xfs_verity.c
> +++ b/fs/xfs/xfs_verity.c
> @@ -622,11 +622,6 @@ xfs_verity_read_merkle(
> if (error)
> goto out_new_mk;
>
> - if (!args.valuelen) {
> - error = -ENODATA;
> - goto out_new_mk;
> - }
> -
> mk = xfs_verity_cache_store(ip, key, new_mk);
> if (mk != new_mk) {
> /*
> @@ -681,6 +676,12 @@ xfs_verity_write_merkle(
> .value = (void *)buf,
> .valuelen = size,
> };
> + const char *p = buf + size - 1;
> +
> + /* Don't store trailing zeroes. */
> + while (p >= (const char *)buf && *p == 0)
> + p--;
> + args.valuelen = p - (const char *)buf + 1;
>
> xfs_verity_merkle_key_to_disk(&name, pos);
> return xfs_attr_set(&args);
>
--
- Andrey
