Commit f5cd0bb5 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
Browse files

qemu-nbd: drop old-style negotiation 

Use new-style negotiation always, with default "" (empty) export name
if it is not specified with '-x' option.

qemu as client can manage either style since 2.6.0, commit 69b49502

For comparison:

nbd 3.10 dropped oldstyle long ago (Mar 2015):
https://github.com/NetworkBlockDevice/nbd/commit/36940193

nbdkit 1.3 switched its default to newstyle (Jan 2018):
https://github.com/libguestfs/nbdkit/commit/b2a8aecc
https://github.com/libguestfs/nbdkit/commit/8158e773



Furthermore, if a client that only speaks oldstyle still needs to
communicate to qemu, nbdkit remains available to perform the
translation between the two protocols.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20181003170228.95973-2-vsementsov@virtuozzo.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
[eblake: enhance commit message]
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent f7812df7

qemu-nbd.c

+6 −19
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ 
#define MBR_SIZE 512



static NBDExport *exp;

static bool newproto;

static int verbose;

static char *srcpath;

static SocketAddress *saddr;
@@ -84,8 +83,8 @@ static void usage(const char *name) 
"  -e, --shared=NUM          device can be shared by NUM clients (default '1')\n"

"  -t, --persistent          don't exit on the last connection\n"

"  -v, --verbose             display extra debugging information\n"

"  -x, --export-name=NAME    expose export by name\n"

"  -D, --description=TEXT    with -x, also export a human-readable description\n"

"  -x, --export-name=NAME    expose export by name (default is empty string)\n"

"  -D, --description=TEXT    export a human-readable description\n"

"\n"

"Exposing part of the image:\n"

"  -o, --offset=OFFSET       offset into the image\n"
@@ -355,8 +354,7 @@ static void nbd_accept(QIONetListener *listener, QIOChannelSocket *cioc, 


    nb_fds++;

    nbd_update_server_watch();

    nbd_client_new(newproto ? NULL : exp, cioc,

                   tlscreds, NULL, nbd_client_closed);

    nbd_client_new(NULL, cioc, tlscreds, NULL, nbd_client_closed);

}



static void nbd_update_server_watch(void)
@@ -550,7 +548,7 @@ int main(int argc, char **argv) 
    Error *local_err = NULL;

    BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;

    QDict *options = NULL;

    const char *export_name = NULL;

    const char *export_name = ""; /* Default export name */

    const char *export_description = NULL;

    const char *tlscredsid = NULL;

    bool imageOpts = false;
@@ -809,11 +807,6 @@ int main(int argc, char **argv) 
            error_report("TLS is not supported with a host device");

            exit(EXIT_FAILURE);

        }

        if (!export_name) {

            /* Set the default NBD protocol export name, since

             * we *must* use new style protocol for TLS */

            export_name = "";

        }

        tlscreds = nbd_get_tls_creds(tlscredsid, &local_err);

        if (local_err) {

            error_report("Failed to get TLS creds %s",
@@ -1014,14 +1007,8 @@ int main(int argc, char **argv) 
        error_report_err(local_err);

        exit(EXIT_FAILURE);

    }

    if (export_name) {

    nbd_export_set_name(exp, export_name);

    nbd_export_set_description(exp, export_description);

        newproto = true;

    } else if (export_description) {

        error_report("Export description requires an export name");

        exit(EXIT_FAILURE);

    }



    if (device) {

        int ret;