[PATCH] dm-verity: do forward error correction on metadata I/O errors

[Mikulas Patocka]

Do forward error correction if metadata I/O fails.

Signed-off-by: Mikulas Patocka <mpato...@redhat.com>

---
 drivers/md/dm-verity-target.c |   19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/md/dm-verity-target.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-verity-target.c        2025-02-04 
13:52:45.000000000 +0100
+++ linux-2.6/drivers/md/dm-verity-target.c     2025-02-10 15:55:42.000000000 
+0100
@@ -324,8 +324,22 @@ static int verity_verify_level(struct dm
                                                &buf, bio->bi_ioprio);
        }
 
-       if (IS_ERR(data))
-               return PTR_ERR(data);
+       if (IS_ERR(data)) {
+               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 +380,7 @@ static int verity_verify_level(struct dm
                }
        }
 
+release_ok:
        data += offset;
        memcpy(want_digest, data, v->digest_size);
        r = 0;