Commit 37e02aeb authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

nbd/server: fix sparse read 



In case of io error in nbd_co_send_sparse_read we should not
"goto reply:", as it was a fatal error and the common behavior
is to disconnect in this case. We should not try to send the
client an additional error reply, since we already hit a
channel-io error on our previous attempt to send one.

Fix this by handling block-status error in nbd_co_send_sparse_read,
so nbd_co_send_sparse_read fails only on io error. Then just skip
common "reply:" code path in nbd_trip.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20180308184636.178534-3-vsementsov@virtuozzo.com>
[eblake: grammar tweaks]
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 60ace2ba

nbd/server.c

+14 −3
Original line number Diff line number Diff line
@@ -1366,6 +1366,10 @@ static int coroutine_fn nbd_co_send_structured_error(NBDClient *client, 
    return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);

}



/* Do a sparse read and send the structured reply to the client.

 * Returns -errno if sending fails. bdrv_block_status_above() failure is

 * reported to the client, at which point this function succeeds.

 */

static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client,

                                                uint64_t handle,

                                                uint64_t offset,
@@ -1386,8 +1390,13 @@ static int coroutine_fn nbd_co_send_sparse_read(NBDClient *client, 
        bool final;



        if (status < 0) {

            error_setg_errno(errp, -status, "unable to check for holes");

            return status;

            char *msg = g_strdup_printf("unable to check for holes: %s",

                                        strerror(-status));



            ret = nbd_co_send_structured_error(client, handle, -status, msg,

                                               errp);

            g_free(msg);

            return ret;

        }

        assert(pnum && pnum <= size - progress);

        final = progress + pnum == size;
@@ -1568,7 +1577,7 @@ static coroutine_fn void nbd_trip(void *opaque) 
                                          request.from, req->data, request.len,

                                          &local_err);

            if (ret < 0) {

                goto reply;

                goto replied;

            }

            goto done;

        }
@@ -1665,6 +1674,8 @@ reply: 
                                       req->data, reply_data_len, &local_err);

    }

    g_free(msg);



replied:

    if (ret < 0) {

        error_prepend(&local_err, "Failed to send reply: ");

        goto disconnect;