Commit a8e2bb6a authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

block/nbd: use non-blocking io channel for nbd negotiation 



No reason to use blocking channel for negotiation and we'll benefit in
further reconnect feature, as qio_channel reads and writes will do
qemu_coroutine_yield while waiting for io completion.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20190618114328.55249-3-vsementsov@virtuozzo.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent 962b7b3d

block/nbd.c

+7 −9
Original line number Diff line number Diff line
@@ -1175,6 +1175,7 @@ static int nbd_client_connect(BlockDriverState *bs, 
                              Error **errp)

{

    BDRVNBDState *s = (BDRVNBDState *)bs->opaque;

    AioContext *aio_context = bdrv_get_aio_context(bs);

    int ret;



    /*
@@ -1189,15 +1190,16 @@ static int nbd_client_connect(BlockDriverState *bs, 


    /* NBD handshake */

    trace_nbd_client_connect(export);

    qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);

    qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);

    qio_channel_attach_aio_context(QIO_CHANNEL(sioc), aio_context);



    s->info.request_sizes = true;

    s->info.structured_reply = true;

    s->info.base_allocation = true;

    s->info.x_dirty_bitmap = g_strdup(x_dirty_bitmap);

    s->info.name = g_strdup(export ?: "");

    ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), tlscreds, hostname,

                                &s->ioc, &s->info, errp);

    ret = nbd_receive_negotiate(aio_context, QIO_CHANNEL(sioc), tlscreds,

                                hostname, &s->ioc, &s->info, errp);

    g_free(s->info.x_dirty_bitmap);

    g_free(s->info.name);

    if (ret < 0) {
@@ -1231,18 +1233,14 @@ static int nbd_client_connect(BlockDriverState *bs, 
        object_ref(OBJECT(s->ioc));

    }



    qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);

    qio_channel_attach_aio_context(s->ioc, bdrv_get_aio_context(bs));



    trace_nbd_client_connect_success(export);



    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.

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

     * Send NBD_CMD_DISC as a courtesy to the server.

     */

    {

        NBDRequest request = { .type = NBD_CMD_DISC };

include/block/nbd.h

+2 −1
Original line number Diff line number Diff line
@@ -304,7 +304,8 @@ struct NBDExportInfo { 
};

typedef struct NBDExportInfo NBDExportInfo;



int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,

                          QCryptoTLSCreds *tlscreds,

                          const char *hostname, QIOChannel **outioc,

                          NBDExportInfo *info, Error **errp);

void nbd_free_export_list(NBDExportInfo *info, int count);

nbd/client.c

+11 −5
Original line number Diff line number Diff line
@@ -867,7 +867,8 @@ static int nbd_list_meta_contexts(QIOChannel *ioc, 
 *          2: server is newstyle, but lacks structured replies

 *          3: server is newstyle and set up for structured replies

 */

static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

static int nbd_start_negotiate(AioContext *aio_context, QIOChannel *ioc,

                               QCryptoTLSCreds *tlscreds,

                               const char *hostname, QIOChannel **outioc,

                               bool structured_reply, bool *zeroes,

                               Error **errp)
@@ -934,6 +935,10 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 
                    return -EINVAL;

                }

                ioc = *outioc;

                if (aio_context) {

                    qio_channel_set_blocking(ioc, false, NULL);

                    qio_channel_attach_aio_context(ioc, aio_context);

                }

            } else {

                error_setg(errp, "Server does not support STARTTLS");

                return -EINVAL;
@@ -998,7 +1003,8 @@ static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info, 
 * Returns: negative errno: failure talking to server

 *          0: server is connected

 */

int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds,

int nbd_receive_negotiate(AioContext *aio_context, QIOChannel *ioc,

                          QCryptoTLSCreds *tlscreds,

                          const char *hostname, QIOChannel **outioc,

                          NBDExportInfo *info, Error **errp)

{
@@ -1009,7 +1015,7 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 
    assert(info->name);

    trace_nbd_receive_negotiate_name(info->name);



    result = nbd_start_negotiate(ioc, tlscreds, hostname, outioc,

    result = nbd_start_negotiate(aio_context, ioc, tlscreds, hostname, outioc,

                                 info->structured_reply, &zeroes, errp);



    info->structured_reply = false;
@@ -1129,8 +1135,8 @@ int nbd_receive_export_list(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 
    QIOChannel *sioc = NULL;



    *info = NULL;

    result = nbd_start_negotiate(ioc, tlscreds, hostname, &sioc, true, NULL,

                                 errp);

    result = nbd_start_negotiate(NULL, ioc, tlscreds, hostname, &sioc, true,

                                 NULL, errp);

    if (tlscreds && sioc) {

        ioc = sioc;

    }

qemu-nbd.c

+1 −1
Original line number Diff line number Diff line
@@ -362,7 +362,7 @@ static void *nbd_client_thread(void *arg) 
        goto out;

    }



    ret = nbd_receive_negotiate(QIO_CHANNEL(sioc),

    ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc),

                                NULL, NULL, NULL, &info, &local_error);

    if (ret < 0) {

        if (local_error) {