zbd: improve replay range validation

The function zbd_replay_write_order() is called when a read is
issued by fio verification code to compare the read data with the
previously written data. Any data mismatch is marked as a verification
failure.

Since zbd_adjust_block() may change the i/o offset and length
to comply with i/o constrains that zoned model has set,
zbd_replay_write_order() needs to replicate the same adjustment during
verify. The general flow in this function matches the write processing
done in zbd_adjust_block(), but there are some differences. For
example, z->verify_block acts as the pseudo-write pointer during replay
and it needs to be advanced by buflen every time the function called,
but it is advanced by min_bs in the existing code (the value of this
variable is measured in min_bs units).

Fix the issue with verify_block and add more error logging to simplify
troubleshooting of this tricky part of ZBD code.

Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Reviewed-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/zbd.c b/zbd.c
index 44ecb9e0b8c99b81ecc1bf2c817b6bf0ffd8613a..1ee238e85f242e3e35f736ae72e09f57b478f98c 100644 (file)
--- a/zbd.c
+++ b/zbd.c
@@ -1239,10 +1239,23 @@ static struct fio_zone_info *zbd_replay_write_order(struct thread_data *td,
                assert(z);
        }
 
-       if (z->verify_block * min_bs >= z->capacity)
+       if (z->verify_block * min_bs >= z->capacity) {
                log_err("%s: %d * %d >= %llu\n", f->file_name, z->verify_block,
                        min_bs, (unsigned long long)z->capacity);
-       io_u->offset = z->start + z->verify_block++ * min_bs;
+               /*
+                * If the assertion below fails during a test run, adding
+                * "--experimental_verify=1" to the command line may help.
+                */
+               assert(false);
+       }
+       io_u->offset = z->start + z->verify_block * min_bs;
+       if (io_u->offset + io_u->buflen >= zbd_zone_capacity_end(z)) {
+               log_err("%s: %llu + %llu >= %lu\n", f->file_name, io_u->offset,
+                       io_u->buflen, zbd_zone_capacity_end(z));
+               assert(false);
+       }
+       z->verify_block += io_u->buflen / min_bs;
+
        return z;
 }