On Mon, Feb 17, 2025 at 10:36:02PM +0100, Mikulas Patocka wrote:
> dm-verity: do forward error correction on metadata I/O errors
>
> Do forward error correction if metadata I/O fails.
>
> Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
>
> ---
> drivers/md/dm-verity-target.c | 25 +++++++++++++++++++++----
> 1 file changed, 21 insertions(+), 4 deletions(-)
>
> Index: linux-2.6/drivers/md/dm-verity-target.c
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-verity-target.c 2025-02-10
> 16:24:56.000000000 +0100
> +++ linux-2.6/drivers/md/dm-verity-target.c 2025-02-17 16:47:37.000000000
> +0100
> @@ -311,7 +311,7 @@ static int verity_verify_level(struct dm
>
> if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
> data = dm_bufio_get(v->bufio, hash_block, &buf);
> - if (data == NULL) {
> + if (IS_ERR_OR_NULL(data)) {
Thanks for adding the check, makes this easier to follow.
> /*
> * In tasklet and the hash was not in the bufio cache.
> * Return early and resume execution from a work-queue
> @@ -324,8 +324,24 @@ static int verity_verify_level(struct dm
> &buf, bio->bi_ioprio);
> }
>
> - if (IS_ERR(data))
> - return PTR_ERR(data);
> + if (IS_ERR(data)) {
> + if (skip_unverified)
> + return 1;
> + r = PTR_ERR(data);
> + data = dm_bufio_new(v->bufio, hash_block, &buf);
> + if (IS_ERR(data))
> + return r;
> + if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_METADATA,
> + hash_block, data) == 0) {
> + aux = dm_bufio_get_aux_data(buf);
> + aux->hash_verified = 1;
> + goto release_ok;
> + } else {
> + dm_bufio_release(buf);
> + dm_bufio_forget(v->bufio, hash_block);
> + return r;
> + }
> + }
>
> aux = dm_bufio_get_aux_data(buf);
>
> @@ -366,6 +382,7 @@ static int verity_verify_level(struct dm
> }
> }
>
> +release_ok:
> data += offset;
> memcpy(want_digest, data, v->digest_size);
> r = 0;
> @@ -1761,7 +1778,7 @@ static struct target_type verity_target
> .name = "verity",
> /* Note: the LSMs depend on the singleton and immutable features */
> .features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
> - .version = {1, 10, 0},
> + .version = {1, 11, 0},
> .module = THIS_MODULE,
> .ctr = verity_ctr,
> .dtr = verity_dtr,
Reviewed-by: Sami Tolvanen <samitolva...@google.com>
Sami
