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Merge remote-tracking branch 'bonzini/nbd-next' into staging

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* bonzini/nbd-next:
  nbd: fixes to read-only handling
  hmp: add NBD server commands
  nbd: disallow nbd-server-add before nbd-server-start
  nbd: force read-only export for read-only devices
  nbd: fix nbd_server_stop crash when no server was running
  nbd: accept URIs
  nbd: accept relative path to Unix socket
  qemu-nbd: initialize main loop before block layer

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori 2012-11-14 08:51:06 -06:00
commit de148eb79c
8 changed files with 274 additions and 35 deletions
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115
block/nbd.c
View File

@ -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"
@ -55,7 +56,6 @@ typedef struct BDRVNBDState {
uint32_t nbdflags;
off_t size;
size_t blocksize;
char *export_name; /* An NBD server may export several devices */
CoMutex send_mutex;
CoMutex free_sema;
@ -65,13 +65,75 @@ typedef struct BDRVNBDState {
Coroutine *recv_coroutine[MAX_NBD_REQUESTS];
struct nbd_reply reply;
/* If it begins with '/', this is a UNIX domain socket. Otherwise,
* it's a string of the form <hostname|ip4|\[ip6\]>:port
*/
int is_unix;
char *host_spec;
char *export_name; /* An NBD server may export several devices */
} BDRVNBDState;
static int nbd_config(BDRVNBDState *s, const char *filename, int flags)
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;
char *export_name;
@ -79,6 +141,10 @@ static int nbd_config(BDRVNBDState *s, const char *filename, int flags)
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);
@ -98,11 +164,10 @@ static int nbd_config(BDRVNBDState *s, const char *filename, int flags)
/* are we a UNIX or TCP socket? */
if (strstart(host_spec, "unix:", &unixpath)) {
if (unixpath[0] != '/') { /* We demand an absolute path*/
goto out;
}
s->is_unix = true;
s->host_spec = g_strdup(unixpath);
} else {
s->is_unix = false;
s->host_spec = g_strdup(host_spec);
}
@ -262,7 +327,7 @@ static int nbd_establish_connection(BlockDriverState *bs)
off_t size;
size_t blocksize;
if (s->host_spec[0] == '/') {
if (s->is_unix) {
sock = unix_socket_outgoing(s->host_spec);
} else {
sock = tcp_socket_outgoing_spec(s->host_spec);
@ -320,7 +385,7 @@ static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
qemu_co_mutex_init(&s->free_sema);
/* Pop the config into our state object. Exit if invalid. */
result = nbd_config(s, filename, flags);
result = nbd_config(s, filename);
if (result != 0) {
return result;
}
@ -498,6 +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,
@ -506,12 +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);

20
blockdev-nbd.c
View File

@ -82,6 +82,11 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
NBDExport *exp;
NBDCloseNotifier *n;
if (server_fd == -1) {
error_setg(errp, "NBD server not running");
return;
}
if (nbd_export_find(device)) {
error_setg(errp, "NBD server already exporting device '%s'", device);
return;
@ -93,6 +98,13 @@ void qmp_nbd_server_add(const char *device, bool has_writable, bool writable,
return;
}
if (!has_writable) {
writable = true;
}
if (bdrv_is_read_only(bs)) {
writable = false;
}
exp = nbd_export_new(bs, 0, -1, writable ? 0 : NBD_FLAG_READ_ONLY,
nbd_server_put_ref);
@ -113,7 +125,9 @@ void qmp_nbd_server_stop(Error **errp)
nbd_close_notifier(&cn->n, nbd_export_get_blockdev(cn->exp));
}
qemu_set_fd_handler2(server_fd, NULL, NULL, NULL, NULL);
close(server_fd);
server_fd = -1;
if (server_fd != -1) {
qemu_set_fd_handler2(server_fd, NULL, NULL, NULL, NULL);
close(server_fd);
server_fd = -1;
}
}

45
hmp-commands.hx
View File

@ -1310,6 +1310,51 @@ Remove all matches from the access control list, and set the default
policy back to @code{deny}.
ETEXI
{
.name = "nbd_server_start",
.args_type = "all:-a,writable:-w,uri:s",
.params = "nbd_server_start [-a] [-w] host:port",
.help = "serve block devices on the given host and port",
.mhandler.cmd = hmp_nbd_server_start,
},
STEXI
@item nbd_server_start @var{host}:@var{port}
@findex nbd_server_start
Start an NBD server on the given host and/or port. If the @option{-a}
option is included, all of the virtual machine's block devices that
have an inserted media on them are automatically exported; in this case,
the @option{-w} option makes the devices writable too.
ETEXI
{
.name = "nbd_server_add",
.args_type = "writable:-w,device:B",
.params = "nbd_server_add [-w] device",
.help = "export a block device via NBD",
.mhandler.cmd = hmp_nbd_server_add,
},
STEXI
@item nbd_server_add @var{device}
@findex nbd_server_add
Export a block device through QEMU's NBD server, which must be started
beforehand with @command{nbd_server_start}. The @option{-w} option makes the
exported device writable too.
ETEXI
{
.name = "nbd_server_stop",
.args_type = "",
.params = "nbd_server_stop",
.help = "stop serving block devices using the NBD protocol",
.mhandler.cmd = hmp_nbd_server_stop,
},
STEXI
@item nbd_server_stop
@findex nbd_server_stop
Stop the QEMU embedded NBD server.
ETEXI
#if defined(TARGET_I386)
{

76
hmp.c
View File

@ -18,6 +18,7 @@
#include "qemu-option.h"
#include "qemu-timer.h"
#include "qmp-commands.h"
#include "qemu_socket.h"
#include "monitor.h"
#include "console.h"
@ -1259,3 +1260,78 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
qmp_screendump(filename, &err);
hmp_handle_error(mon, &err);
}
void hmp_nbd_server_start(Monitor *mon, const QDict *qdict)
{
const char *uri = qdict_get_str(qdict, "uri");
int writable = qdict_get_try_bool(qdict, "writable", 0);
int all = qdict_get_try_bool(qdict, "all", 0);
Error *local_err = NULL;
BlockInfoList *block_list, *info;
SocketAddress *addr;
if (writable && !all) {
error_setg(&local_err, "-w only valid together with -a");
goto exit;
}
/* First check if the address is valid and start the server. */
addr = socket_parse(uri, &local_err);
if (local_err != NULL) {
goto exit;
}
qmp_nbd_server_start(addr, &local_err);
qapi_free_SocketAddress(addr);
if (local_err != NULL) {
goto exit;
}
if (!all) {
return;
}
/* Then try adding all block devices. If one fails, close all and
* exit.
*/
block_list = qmp_query_block(NULL);
for (info = block_list; info; info = info->next) {
if (!info->value->has_inserted) {
continue;
}
qmp_nbd_server_add(info->value->device, true, writable, &local_err);
if (local_err != NULL) {
qmp_nbd_server_stop(NULL);
break;
}
}
qapi_free_BlockInfoList(block_list);
exit:
hmp_handle_error(mon, &local_err);
}
void hmp_nbd_server_add(Monitor *mon, const QDict *qdict)
{
const char *device = qdict_get_str(qdict, "device");
int writable = qdict_get_try_bool(qdict, "writable", 0);
Error *local_err = NULL;
qmp_nbd_server_add(device, true, writable, &local_err);
if (local_err != NULL) {
hmp_handle_error(mon, &local_err);
}
}
void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict)
{
Error *errp = NULL;
qmp_nbd_server_stop(&errp);
hmp_handle_error(mon, &errp);
}

3
hmp.h
View File

@ -77,5 +77,8 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
void hmp_closefd(Monitor *mon, const QDict *qdict);
void hmp_send_key(Monitor *mon, const QDict *qdict);
void hmp_screen_dump(Monitor *mon, const QDict *qdict);
void hmp_nbd_server_start(Monitor *mon, const QDict *qdict);
void hmp_nbd_server_add(Monitor *mon, const QDict *qdict);
void hmp_nbd_server_stop(Monitor *mon, const QDict *qdict);
#endif

23
nbd.c
View File

@ -596,24 +596,23 @@ int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize)
return -serrno;
}
if (flags & NBD_FLAG_READ_ONLY) {
int read_only = 1;
TRACE("Setting readonly attribute");
if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) {
if (errno == ENOTTY) {
int read_only = (flags & NBD_FLAG_READ_ONLY) != 0;
TRACE("Setting readonly attribute");
if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) {
int serrno = errno;
LOG("Failed setting read-only attribute");
return -serrno;
}
} else {
int serrno = errno;
LOG("Failed setting read-only attribute");
LOG("Failed setting flags");
return -serrno;
}
}
if (ioctl(fd, NBD_SET_FLAGS, flags) < 0
&& errno != ENOTTY) {
int serrno = errno;
LOG("Failed setting flags");
return -serrno;
}
TRACE("Negotiation ended");
return 0;

25
qemu-doc.texi
View File

@ -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

2
qemu-nbd.c
View File

@ -539,6 +539,7 @@ int main(int argc, char **argv)
snprintf(sockpath, 128, SOCKET_PATH, basename(device));
}
qemu_init_main_loop();
bdrv_init();
atexit(bdrv_close_all);
@ -584,7 +585,6 @@ int main(int argc, char **argv)
memset(&client_thread, 0, sizeof(client_thread));
}
qemu_init_main_loop();
qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
(void *)(uintptr_t)fd);