Commit 23e099c3 authored by Eric Blake's avatar Eric Blake Committed by Paolo Bonzini
Browse files

nbd: Refactor reply to NBD_OPT_EXPORT_NAME 



Reply directly in nbd_negotiate_handle_export_name(), rather than
waiting until nbd_negotiate_options() completes.  This will make it
easier to implement NBD_OPT_GO.  Pass additional parameters around,
rather than stashing things inside NBDClient.

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20170707203049.534-6-eblake@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 621c4f4e

nbd/server.c

+28 −22
Original line number Diff line number Diff line
@@ -84,7 +84,6 @@ struct NBDClient { 
    int refcount;

    void (*close_fn)(NBDClient *client, bool negotiated);



    bool no_zeroes;

    NBDExport *exp;

    QCryptoTLSCreds *tlscreds;

    char *tlsaclname;
@@ -277,9 +276,13 @@ static int nbd_negotiate_handle_list(NBDClient *client, uint32_t length, 
}



static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length,

                                            uint16_t myflags, bool no_zeroes,

                                            Error **errp)

{

    char name[NBD_MAX_NAME_SIZE + 1];

    char buf[8 + 4 + 124] = "";

    size_t len;

    int ret;



    /* Client sends:

        [20 ..  xx]   export name (length bytes)
@@ -303,6 +306,17 @@ static int nbd_negotiate_handle_export_name(NBDClient *client, uint32_t length, 
        return -EINVAL;

    }



    trace_nbd_negotiate_new_style_size_flags(client->exp->size,

                                             client->exp->nbdflags | myflags);

    stq_be_p(buf, client->exp->size);

    stw_be_p(buf + 8, client->exp->nbdflags | myflags);

    len = no_zeroes ? 10 : sizeof(buf);

    ret = nbd_write(client->ioc, buf, len, errp);

    if (ret < 0) {

        error_prepend(errp, "write failed: ");

        return ret;

    }



    QTAILQ_INSERT_TAIL(&client->exp->clients, client, next);

    nbd_export_get(client->exp);
@@ -373,14 +387,17 @@ static QIOChannel *nbd_negotiate_handle_starttls(NBDClient *client, 
 * 1       if client sent NBD_OPT_ABORT, i.e. on valid disconnect,

 *         errp is not set

 */

static int nbd_negotiate_options(NBDClient *client, Error **errp)

static int nbd_negotiate_options(NBDClient *client, uint16_t myflags,

                                 Error **errp)

{

    uint32_t flags;

    bool fixedNewstyle = false;

    bool no_zeroes = false;



    /* Client sends:

        [ 0 ..   3]   client flags



       Then we loop until NBD_OPT_EXPORT_NAME:

        [ 0 ..   7]   NBD_OPTS_MAGIC

        [ 8 ..  11]   NBD option

        [12 ..  15]   Data length
@@ -403,7 +420,7 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp) 
        flags &= ~NBD_FLAG_C_FIXED_NEWSTYLE;

    }

    if (flags & NBD_FLAG_C_NO_ZEROES) {

        client->no_zeroes = true;

        no_zeroes = true;

        flags &= ~NBD_FLAG_C_NO_ZEROES;

    }

    if (flags != 0) {
@@ -503,7 +520,9 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp) 
                return 1;



            case NBD_OPT_EXPORT_NAME:

                return nbd_negotiate_handle_export_name(client, length, errp);

                return nbd_negotiate_handle_export_name(client, length,

                                                        myflags, no_zeroes,

                                                        errp);



            case NBD_OPT_STARTTLS:

                if (nbd_drop(client->ioc, length, errp) < 0) {
@@ -546,7 +565,9 @@ static int nbd_negotiate_options(NBDClient *client, Error **errp) 
             */

            switch (option) {

            case NBD_OPT_EXPORT_NAME:

                return nbd_negotiate_handle_export_name(client, length, errp);

                return nbd_negotiate_handle_export_name(client, length,

                                                        myflags, no_zeroes,

                                                        errp);



            default:

                error_setg(errp, "Unsupported option 0x%" PRIx32 " (%s)",
@@ -572,7 +593,6 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 
                              NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA |

                              NBD_FLAG_SEND_WRITE_ZEROES);

    bool oldStyle;

    size_t len;



    /* Old style negotiation header without options

        [ 0 ..   7]   passwd       ("NBDMAGIC")
@@ -586,10 +606,7 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 
        [ 0 ..   7]   passwd       ("NBDMAGIC")

        [ 8 ..  15]   magic        (NBD_OPTS_MAGIC)

        [16 ..  17]   server flags (0)

        ....options sent....

        [18 ..  25]   size

        [26 ..  27]   export flags

        [28 .. 151]   reserved     (0, omit if no_zeroes)

        ....options sent, ending in NBD_OPT_EXPORT_NAME....

     */



    qio_channel_set_blocking(client->ioc, false, NULL);
@@ -618,24 +635,13 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp) 
            error_prepend(errp, "write failed: ");

            return -EINVAL;

        }

        ret = nbd_negotiate_options(client, errp);

        ret = nbd_negotiate_options(client, myflags, errp);

        if (ret != 0) {

            if (ret < 0) {

                error_prepend(errp, "option negotiation failed: ");

            }

            return ret;

        }



        trace_nbd_negotiate_new_style_size_flags(

            client->exp->size, client->exp->nbdflags | myflags);

        stq_be_p(buf + 18, client->exp->size);

        stw_be_p(buf + 26, client->exp->nbdflags | myflags);

        len = client->no_zeroes ? 10 : sizeof(buf) - 18;

        ret = nbd_write(client->ioc, buf + 18, len, errp);

        if (ret < 0) {

            error_prepend(errp, "write failed: ");

            return ret;

        }

    }



    trace_nbd_negotiate_success();