dm verity: fix error handling for check_at_most_once on FEC

BugLink: https://bugs.launchpad.net/bugs/2025067
commit e8c5d45f82ce0c238a4817739892fe8897a3dcc3 upstream.

In verity_end_io(), if bi_status is not BLK_STS_OK, it can be return
directly. But if FEC configured, it is desired to correct the data page
through verity_verify_io. And the return value will be converted to
blk_status and passed to verity_finish_io().

BTW, when a bit is set in v->validated_blocks, verity_verify_io() skips
verification regardless of I/O error for the corresponding bio. In this
case, the I/O error could not be returned properly, and as a result,
there is a problem that abnormal data could be read for the
corresponding block.

To fix this problem, when an I/O error occurs, do not skip verification
even if the bit related is set in v->validated_blocks.

Fixes: 843f38d382b1 ("dm verity: add 'check_at_most_once' option to only validate hashes once")
Cc: stable@vger.kernel.org
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Yeongjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 64e8ac429984d9fb103e0781e8eb18740a5bb5b9..14a9988ec30ba1859e8ffb087d15a0c063f2812e 100644 (file)
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -523,7 +523,7 @@ static int verity_verify_io(struct dm_verity_io *io)
                sector_t cur_block = io->block + b;
                struct ahash_request *req = verity_io_hash_req(v, io);
 
-               if (v->validated_blocks &&
+               if (v->validated_blocks && bio->bi_status == BLK_STS_OK &&
                    likely(test_bit(cur_block, v->validated_blocks))) {
                        verity_bv_skip_block(v, io, iter);
                        continue;