Commit b3c9d33b authored by Eric Blake's avatar Eric Blake
Browse files

nbd/client: Pull out oldstyle size determination 



Another refactoring creating nbd_negotiate_finish_oldstyle()
for further reuse during 'qemu-nbd --list'.

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarRichard W.M. Jones <rjones@redhat.com>
Message-Id: <20190117193658.16413-16-eblake@redhat.com>
Reviewed-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
parent 10b89988

nbd/client.c

+32 −17
Original line number Diff line number Diff line
@@ -814,7 +814,7 @@ static int nbd_negotiate_simple_meta_context(QIOChannel *ioc, 
 * Start the handshake to the server.  After a positive return, the server

 * is ready to accept additional NBD_OPT requests.

 * Returns: negative errno: failure talking to server

 *          0: server is oldstyle, client must still parse export size

 *          0: server is oldstyle, must call nbd_negotiate_finish_oldstyle

 *          1: server is newstyle, but can only accept EXPORT_NAME

 *          2: server is newstyle, but lacks structured replies

 *          3: server is newstyle and set up for structured replies
@@ -920,6 +920,36 @@ static int nbd_start_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 
    }

}



/*

 * nbd_negotiate_finish_oldstyle:

 * Populate @info with the size and export flags from an oldstyle server,

 * but does not consume 124 bytes of reserved zero padding.

 * Returns 0 on success, -1 with @errp set on failure

 */

static int nbd_negotiate_finish_oldstyle(QIOChannel *ioc, NBDExportInfo *info,

                                         Error **errp)

{

    uint32_t oldflags;



    if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {

        error_prepend(errp, "Failed to read export length: ");

        return -EINVAL;

    }

    info->size = be64_to_cpu(info->size);



    if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {

        error_prepend(errp, "Failed to read export flags: ");

        return -EINVAL;

    }

    oldflags = be32_to_cpu(oldflags);

    if (oldflags & ~0xffff) {

        error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);

        return -EINVAL;

    }

    info->flags = oldflags;

    return 0;

}



/*

 * nbd_receive_negotiate:

 * Connect to server, complete negotiation, and move into transmission phase.
@@ -933,7 +963,6 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 
    int result;

    bool zeroes;

    bool base_allocation = info->base_allocation;

    uint32_t oldflags;



    assert(info->name);

    trace_nbd_receive_negotiate_name(info->name);
@@ -1006,23 +1035,9 @@ int nbd_receive_negotiate(QIOChannel *ioc, QCryptoTLSCreds *tlscreds, 
            error_setg(errp, "Server does not support non-empty export names");

            return -EINVAL;

        }



        if (nbd_read(ioc, &info->size, sizeof(info->size), errp) < 0) {

            error_prepend(errp, "Failed to read export length: ");

            return -EINVAL;

        }

        info->size = be64_to_cpu(info->size);



        if (nbd_read(ioc, &oldflags, sizeof(oldflags), errp) < 0) {

            error_prepend(errp, "Failed to read export flags: ");

            return -EINVAL;

        }

        oldflags = be32_to_cpu(oldflags);

        if (oldflags & ~0xffff) {

            error_setg(errp, "Unexpected export flags %0x" PRIx32, oldflags);

        if (nbd_negotiate_finish_oldstyle(ioc, info, errp) < 0) {

            return -EINVAL;

        }

        info->flags = oldflags;

        break;

    default:

        return result;