Commit a57f6dea authored by Eric Blake's avatar Eric Blake
Browse files

nbd/server: Include human-readable message in structured errors 



The NBD spec permits including a human-readable error string if
structured replies are in force, so we might as well send the
client the message that we logged on any error.

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20171027104037.8319-9-eblake@redhat.com>
parent 5c54e7fa

nbd/server.c

+13 −7
Original line number Diff line number Diff line
@@ -1296,24 +1296,25 @@ static int coroutine_fn nbd_co_send_structured_read(NBDClient *client, 
static int coroutine_fn nbd_co_send_structured_error(NBDClient *client,

                                                     uint64_t handle,

                                                     uint32_t error,

                                                     const char *msg,

                                                     Error **errp)

{

    NBDStructuredError chunk;

    int nbd_err = system_errno_to_nbd_errno(error);

    struct iovec iov[] = {

        {.iov_base = &chunk, .iov_len = sizeof(chunk)},

        /* FIXME: Support human-readable error message */

        {.iov_base = (char *)msg, .iov_len = msg ? strlen(msg) : 0},

    };



    assert(nbd_err);

    trace_nbd_co_send_structured_error(handle, nbd_err,

                                       nbd_err_lookup(nbd_err));

                                       nbd_err_lookup(nbd_err), msg ? msg : "");

    set_be_chunk(&chunk.h, NBD_REPLY_FLAG_DONE, NBD_REPLY_TYPE_ERROR, handle,

                 sizeof(chunk) - sizeof(chunk.h));

                 sizeof(chunk) - sizeof(chunk.h) + iov[1].iov_len);

    stl_be_p(&chunk.error, nbd_err);

    stw_be_p(&chunk.message_length, 0);

    stw_be_p(&chunk.message_length, iov[1].iov_len);



    return nbd_co_send_iov(client, iov, 1, errp);

    return nbd_co_send_iov(client, iov, 1 + !!iov[1].iov_len, errp);

}



/* nbd_co_receive_request
@@ -1414,6 +1415,7 @@ static coroutine_fn void nbd_trip(void *opaque) 
    int flags;

    int reply_data_len = 0;

    Error *local_err = NULL;

    char *msg = NULL;



    trace_nbd_trip();

    if (client->closing) {
@@ -1530,14 +1532,17 @@ reply: 
    if (local_err) {

        /* If we get here, local_err was not a fatal error, and should be sent

         * to the client. */

        assert(ret < 0);

        msg = g_strdup(error_get_pretty(local_err));

        error_report_err(local_err);

        local_err = NULL;

    }



    if (client->structured_reply && request.type == NBD_CMD_READ) {

    if (client->structured_reply &&

        (ret < 0 || request.type == NBD_CMD_READ)) {

        if (ret < 0) {

            ret = nbd_co_send_structured_error(req->client, request.handle,

                                               -ret, &local_err);

                                               -ret, msg, &local_err);

        } else {

            ret = nbd_co_send_structured_read(req->client, request.handle,

                                              request.from, req->data,
@@ -1548,6 +1553,7 @@ reply: 
                                       ret < 0 ? -ret : 0,

                                       req->data, reply_data_len, &local_err);

    }

    g_free(msg);

    if (ret < 0) {

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

        goto disconnect;

nbd/trace-events

+1 −1
Original line number Diff line number Diff line
@@ -57,7 +57,7 @@ nbd_blk_aio_attached(const char *name, void *ctx) "Export %s: Attaching clients 
nbd_blk_aio_detach(const char *name, void *ctx) "Export %s: Detaching clients from AIO context %p\n"

nbd_co_send_simple_reply(uint64_t handle, uint32_t error, const char *errname, int len) "Send simple reply: handle = %" PRIu64 ", error = %" PRIu32 " (%s), len = %d"

nbd_co_send_structured_read(uint64_t handle, uint64_t offset, void *data, size_t size) "Send structured read data reply: handle = %" PRIu64 ", offset = %" PRIu64 ", data = %p, len = %zu"

nbd_co_send_structured_error(uint64_t handle, int err, const char *errname) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s)"

nbd_co_send_structured_error(uint64_t handle, int err, const char *errname, const char *msg) "Send structured error reply: handle = %" PRIu64 ", error = %d (%s), msg = '%s'"

nbd_co_receive_request_decode_type(uint64_t handle, uint16_t type, const char *name) "Decoding type: handle = %" PRIu64 ", type = %" PRIu16 " (%s)"

nbd_co_receive_request_payload_received(uint64_t handle, uint32_t len) "Payload received: handle = %" PRIu64 ", len = %" PRIu32

nbd_co_receive_request_cmd_write(uint32_t len) "Reading %" PRIu32 " byte(s)"