Commit 1d7d2a9d authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

nbd: accept URIs 



The URI syntax is consistent with the Gluster syntax.  Export names
are specified in the path, preceded by one or more (otherwise unused)
slashes.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d04b0bbb

block/nbd.c

+97 −1
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 


#include "qemu-common.h"

#include "nbd.h"

#include "uri.h"

#include "block_int.h"

#include "module.h"

#include "qemu_socket.h"
@@ -69,6 +70,69 @@ typedef struct BDRVNBDState { 
    char *export_name; /* An NBD server may export several devices */

} BDRVNBDState;



static int nbd_parse_uri(BDRVNBDState *s, const char *filename)

{

    URI *uri;

    const char *p;

    QueryParams *qp = NULL;

    int ret = 0;



    uri = uri_parse(filename);

    if (!uri) {

        return -EINVAL;

    }



    /* transport */

    if (!strcmp(uri->scheme, "nbd")) {

        s->is_unix = false;

    } else if (!strcmp(uri->scheme, "nbd+tcp")) {

        s->is_unix = false;

    } else if (!strcmp(uri->scheme, "nbd+unix")) {

        s->is_unix = true;

    } else {

        ret = -EINVAL;

        goto out;

    }



    p = uri->path ? uri->path : "/";

    p += strspn(p, "/");

    if (p[0]) {

        s->export_name = g_strdup(p);

    }



    qp = query_params_parse(uri->query);

    if (qp->n > 1 || (s->is_unix && !qp->n) || (!s->is_unix && qp->n)) {

        ret = -EINVAL;

        goto out;

    }



    if (s->is_unix) {

        /* nbd+unix:///export?socket=path */

        if (uri->server || uri->port || strcmp(qp->p[0].name, "socket")) {

            ret = -EINVAL;

            goto out;

        }

        s->host_spec = g_strdup(qp->p[0].value);

    } else {

        /* nbd[+tcp]://host:port/export */

        if (!uri->server) {

            ret = -EINVAL;

            goto out;

        }

        if (!uri->port) {

            uri->port = NBD_DEFAULT_PORT;

        }

        s->host_spec = g_strdup_printf("%s:%d", uri->server, uri->port);

    }



out:

    if (qp) {

        query_params_free(qp);

    }

    uri_free(uri);

    return ret;

}



static int nbd_config(BDRVNBDState *s, const char *filename)

{

    char *file;
@@ -77,6 +141,10 @@ static int nbd_config(BDRVNBDState *s, const char *filename) 
    const char *unixpath;

    int err = -EINVAL;



    if (strstr(filename, "://")) {

        return nbd_parse_uri(s, filename);

    }



    file = g_strdup(filename);



    export_name = strstr(file, EN_OPTSTR);
@@ -495,6 +563,33 @@ static int64_t nbd_getlength(BlockDriverState *bs) 


static BlockDriver bdrv_nbd = {

    .format_name         = "nbd",

    .protocol_name       = "nbd",

    .instance_size       = sizeof(BDRVNBDState),

    .bdrv_file_open      = nbd_open,

    .bdrv_co_readv       = nbd_co_readv,

    .bdrv_co_writev      = nbd_co_writev,

    .bdrv_close          = nbd_close,

    .bdrv_co_flush_to_os = nbd_co_flush,

    .bdrv_co_discard     = nbd_co_discard,

    .bdrv_getlength      = nbd_getlength,

};



static BlockDriver bdrv_nbd_tcp = {

    .format_name         = "nbd",

    .protocol_name       = "nbd+tcp",

    .instance_size       = sizeof(BDRVNBDState),

    .bdrv_file_open      = nbd_open,

    .bdrv_co_readv       = nbd_co_readv,

    .bdrv_co_writev      = nbd_co_writev,

    .bdrv_close          = nbd_close,

    .bdrv_co_flush_to_os = nbd_co_flush,

    .bdrv_co_discard     = nbd_co_discard,

    .bdrv_getlength      = nbd_getlength,

};



static BlockDriver bdrv_nbd_unix = {

    .format_name         = "nbd",

    .protocol_name       = "nbd+unix",

    .instance_size       = sizeof(BDRVNBDState),

    .bdrv_file_open      = nbd_open,

    .bdrv_co_readv       = nbd_co_readv,
@@ -503,12 +598,13 @@ static BlockDriver bdrv_nbd = { 
    .bdrv_co_flush_to_os = nbd_co_flush,

    .bdrv_co_discard     = nbd_co_discard,

    .bdrv_getlength      = nbd_getlength,

    .protocol_name       = "nbd",

};



static void bdrv_nbd_init(void)

{

    bdrv_register(&bdrv_nbd);

    bdrv_register(&bdrv_nbd_tcp);

    bdrv_register(&bdrv_nbd_unix);

}



block_init(bdrv_nbd_init);

qemu-doc.texi

+17 −8
Original line number Diff line number Diff line
@@ -610,14 +610,14 @@ QEMU can access directly to block device exported using the Network Block Device 
protocol.



@example

qemu-system-i386 linux.img -hdb nbd:my_nbd_server.mydomain.org:1024

qemu-system-i386 linux.img -hdb nbd://my_nbd_server.mydomain.org:1024/

@end example



If the NBD server is located on the same host, you can use an unix socket instead

of an inet socket:



@example

qemu-system-i386 linux.img -hdb nbd:unix:/tmp/my_socket

qemu-system-i386 linux.img -hdb nbd+unix://?socket=/tmp/my_socket

@end example



In this case, the block device must be exported using qemu-nbd:
@@ -631,17 +631,26 @@ The use of qemu-nbd allows to share a disk between several guests: 
qemu-nbd --socket=/tmp/my_socket --share=2 my_disk.qcow2

@end example



@noindent

and then you can use it with two guests:

@example

qemu-system-i386 linux1.img -hdb nbd:unix:/tmp/my_socket

qemu-system-i386 linux2.img -hdb nbd:unix:/tmp/my_socket

qemu-system-i386 linux1.img -hdb nbd+unix://?socket=/tmp/my_socket

qemu-system-i386 linux2.img -hdb nbd+unix://?socket=/tmp/my_socket

@end example



If the nbd-server uses named exports (since NBD 2.9.18), you must use the

"exportname" option:

If the nbd-server uses named exports (supported since NBD 2.9.18, or with QEMU's

own embedded NBD server), you must specify an export name in the URI:

@example

qemu-system-i386 -cdrom nbd:localhost:exportname=debian-500-ppc-netinst

qemu-system-i386 -cdrom nbd:localhost:exportname=openSUSE-11.1-ppc-netinst

qemu-system-i386 -cdrom nbd://localhost/debian-500-ppc-netinst

qemu-system-i386 -cdrom nbd://localhost/openSUSE-11.1-ppc-netinst

@end example



The URI syntax for NBD is supported since QEMU 1.3.  An alternative syntax is

also available.  Here are some example of the older syntax:

@example

qemu-system-i386 linux.img -hdb nbd:my_nbd_server.mydomain.org:1024

qemu-system-i386 linux2.img -hdb nbd:unix:/tmp/my_socket

qemu-system-i386 -cdrom nbd:localhost:10809:exportname=debian-500-ppc-netinst

@end example



@node disk_images_sheepdog