Commit c688e6ca authored by Eric Blake's avatar Eric Blake
Browse files

nbd/client: Send NBD_CMD_DISC if open fails after connect 



If nbd_client_init() fails after we are already connected,
then the server will spam logs with:

Disconnect client, due to: Unexpected end-of-file before all bytes were read

unless we gracefully disconnect before closing the connection.

Ways to trigger this:

$ opts=driver=nbd,export=foo,server.type=inet,server.host=localhost,server.port=10809
$  qemu-img map --output=json --image-opts $opts,read-only=off
$  qemu-img map --output=json --image-opts $opts,x-dirty-bitmap=nosuch:

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20181130023232.3079982-4-eblake@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
parent 47829c40

block/nbd-client.c

+16 −2
Original line number Diff line number Diff line
@@ -995,12 +995,13 @@ int nbd_client_init(BlockDriverState *bs, 
    if (x_dirty_bitmap && !client->info.base_allocation) {

        error_setg(errp, "requested x-dirty-bitmap %s not found",

                   x_dirty_bitmap);

        return -EINVAL;

        ret = -EINVAL;

        goto fail;

    }

    if (client->info.flags & NBD_FLAG_READ_ONLY) {

        ret = bdrv_apply_auto_read_only(bs, "NBD export is read-only", errp);

        if (ret < 0) {

            return ret;

            goto fail;

        }

    }

    if (client->info.flags & NBD_FLAG_SEND_FUA) {
@@ -1029,4 +1030,17 @@ int nbd_client_init(BlockDriverState *bs, 


    logout("Established connection with NBD server\n");

    return 0;



 fail:

    /*

     * We have connected, but must fail for other reasons. The

     * connection is still blocking; send NBD_CMD_DISC as a courtesy

     * to the server.

     */

    {

        NBDRequest request = { .type = NBD_CMD_DISC };



        nbd_send_request(client->ioc ?: QIO_CHANNEL(sioc), &request);

        return ret;

    }

}