Re: [PATCH 03/11] ntfs: punch all-zero compressed blocks

2026=EB=85=84 7=EC=9B=94 21=EC=9D=BC (=ED=99=94) =EC=98=A4=ED=9B=84 6:54, N=
amjae Jeon <[email protected]>=EB=8B=98=EC=9D=B4 =EC=9E=91=EC=84=B1:
>
> When a rewritten compression block consists entirely of zeroes,
> ntfs_write_cb() returns without replacing its existing runlist mapping.
> The old on-disk contents therefore remain visible after cache eviction.
>
> Punch the compression unit so that reads resolve it as a sparse block and
> release any clusters that held the previous contents.
>
> Signed-off-by: Namjae Jeon <[email protected]>

Looks good to me.

Reviewed-by: Hyunchul Lee <[email protected]>


> ---
>  fs/ntfs/compress.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ntfs/compress.c b/fs/ntfs/compress.c
> index 006b8831836c..33ed0456bf7e 100644
> --- a/fs/ntfs/compress.c
> +++ b/fs/ntfs/compress.c
> @@ -1279,9 +1279,10 @@ static int ntfs_write_cb(struct ntfs_inode *ni, lo=
ff_t pos, struct page **pages,
>         int i, err;
>         int pages_count =3D (round_up(ni->itype.compressed.block_size + 2=
 *
>                 (ni->itype.compressed.block_size / NTFS_SB_SIZE) + 2, PAG=
E_SIZE)) / PAGE_SIZE;
> +       u32 cb_clusters =3D ni->itype.compressed.block_clusters;
>         size_t new_rl_count;
>         struct bio *bio =3D NULL;
> -       loff_t new_length;
> +       loff_t cb_pos, new_length;
>         s64 new_vcn;
>
>         in_mapping =3D vmap(pages, pages_per_cb, VM_MAP, PAGE_KERNEL_RO);
> @@ -1351,6 +1352,9 @@ static int ntfs_write_cb(struct ntfs_inode *ni, lof=
f_t pos, struct page **pages,
>                 }
>         }
>
> +       cb_pos =3D pos & ~((loff_t)ni->itype.compressed.block_size - 1);
> +       new_vcn =3D ntfs_bytes_to_cluster(vol, cb_pos);
> +
>         if (!fail && !allzeroes) {
>                 outbuf[compsz++] =3D 0;
>                 outbuf[compsz++] =3D 0;
> @@ -1359,7 +1363,7 @@ static int ntfs_write_cb(struct ntfs_inode *ni, lof=
f_t pos, struct page **pages,
>                 bio_size =3D rounded;
>                 pages =3D pages_disk;
>         } else if (allzeroes) {
> -               err =3D 0;
> +               err =3D ntfs_non_resident_attr_punch_hole(ni, new_vcn, cb=
_clusters);
>                 goto out;
>         } else {
>                 memcpy(outbuf, inbuf, insz);
> @@ -1367,8 +1371,6 @@ static int ntfs_write_cb(struct ntfs_inode *ni, lof=
f_t pos, struct page **pages,
>                 pages =3D pages_disk;
>         }
>
> -       new_vcn =3D ntfs_bytes_to_cluster(vol,
> -                       pos & ~((loff_t)ni->itype.compressed.block_size -=
 1));
>         new_length =3D ntfs_bytes_to_cluster(vol, round_up(bio_size, vol-=
>cluster_size));
>
>         err =3D ntfs_non_resident_attr_punch_hole(ni, new_vcn, ni->itype.=
compressed.block_clusters);
> --
> 2.34.1
>


--=20
Thanks,
Hyunchul