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qemu/block/rbd.c
Josh Durgin dc7588c1eb rbd: add an asynchronous flush 
The existing bdrv_co_flush_to_disk implementation uses rbd_flush(),
which is sychronous and causes the main qemu thread to block until it
is complete. This results in unresponsiveness and extra latency for
the guest.

Fix this by using an asynchronous version of flush.  This was added to
librbd with a special #define to indicate its presence, since it will
be backported to stable versions. Thus, there is no need to check the
version of librbd.

Implement this as bdrv_aio_flush, since it matches other aio functions
in the rbd block driver, and leave out bdrv_co_flush_to_disk when the
asynchronous version is available.

Reported-by: Oliver Francke <oliver@filoo.de>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-04-15 10:18:05 +02:00

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/*
* QEMU Block driver for RADOS (Ceph)
*
* Copyright (C) 2010-2011 Christian Brunner <chb@muc.de>,
* Josh Durgin <josh.durgin@dreamhost.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include <inttypes.h>
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "block/block_int.h"
#include <rbd/librbd.h>
/*
* When specifying the image filename use:
*
* rbd:poolname/devicename[@snapshotname][:option1=value1[:option2=value2...]]
*
* poolname must be the name of an existing rados pool.
*
* devicename is the name of the rbd image.
*
* Each option given is used to configure rados, and may be any valid
* Ceph option, "id", or "conf".
*
* The "id" option indicates what user we should authenticate as to
* the Ceph cluster. If it is excluded we will use the Ceph default
* (normally 'admin').
*
* The "conf" option specifies a Ceph configuration file to read. If
* it is not specified, we will read from the default Ceph locations
* (e.g., /etc/ceph/ceph.conf). To avoid reading _any_ configuration
* file, specify conf=/dev/null.
*
* Configuration values containing :, @, or = can be escaped with a
* leading "\".
*/
/* rbd_aio_discard added in 0.1.2 */
#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 2)
#define LIBRBD_SUPPORTS_DISCARD
#else
#undef LIBRBD_SUPPORTS_DISCARD
#endif
#define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
#define RBD_MAX_CONF_NAME_SIZE 128
#define RBD_MAX_CONF_VAL_SIZE 512
#define RBD_MAX_CONF_SIZE 1024
#define RBD_MAX_POOL_NAME_SIZE 128
#define RBD_MAX_SNAP_NAME_SIZE 128
#define RBD_MAX_SNAPS 100
typedef enum {
RBD_AIO_READ,
RBD_AIO_WRITE,
RBD_AIO_DISCARD,
RBD_AIO_FLUSH
} RBDAIOCmd;
typedef struct RBDAIOCB {
BlockDriverAIOCB common;
QEMUBH *bh;
int64_t ret;
QEMUIOVector *qiov;
char *bounce;
RBDAIOCmd cmd;
int64_t sector_num;
int error;
struct BDRVRBDState *s;
int cancelled;
int status;
} RBDAIOCB;
typedef struct RADOSCB {
int rcbid;
RBDAIOCB *acb;
struct BDRVRBDState *s;
int done;
int64_t size;
char *buf;
int64_t ret;
} RADOSCB;
#define RBD_FD_READ 0
#define RBD_FD_WRITE 1
typedef struct BDRVRBDState {
int fds[2];
rados_t cluster;
rados_ioctx_t io_ctx;
rbd_image_t image;
char name[RBD_MAX_IMAGE_NAME_SIZE];
int qemu_aio_count;
char *snap;
int event_reader_pos;
RADOSCB *event_rcb;
} BDRVRBDState;
static void rbd_aio_bh_cb(void *opaque);
static int qemu_rbd_next_tok(char *dst, int dst_len,
char *src, char delim,
const char *name,
char **p)
{
int l;
char *end;
*p = NULL;
if (delim != '\0') {
for (end = src; *end; ++end) {
if (*end == delim) {
break;
}
if (*end == '\\' && end[1] != '\0') {
end++;
}
}
if (*end == delim) {
*p = end + 1;
*end = '\0';
}
}
l = strlen(src);
if (l >= dst_len) {
error_report("%s too long", name);
return -EINVAL;
} else if (l == 0) {
error_report("%s too short", name);
return -EINVAL;
}
pstrcpy(dst, dst_len, src);
return 0;
}
static void qemu_rbd_unescape(char *src)
{
char *p;
for (p = src; *src; ++src, ++p) {
if (*src == '\\' && src[1] != '\0') {
src++;
}
*p = *src;
}
*p = '\0';
}
static int qemu_rbd_parsename(const char *filename,
char *pool, int pool_len,
char *snap, int snap_len,
char *name, int name_len,
char *conf, int conf_len)
{
const char *start;
char *p, *buf;
int ret;
if (!strstart(filename, "rbd:", &start)) {
return -EINVAL;
}
buf = g_strdup(start);
p = buf;
*snap = '\0';
*conf = '\0';
ret = qemu_rbd_next_tok(pool, pool_len, p, '/', "pool name", &p);
if (ret < 0 || !p) {
ret = -EINVAL;
goto done;
}
qemu_rbd_unescape(pool);
if (strchr(p, '@')) {
ret = qemu_rbd_next_tok(name, name_len, p, '@', "object name", &p);
if (ret < 0) {
goto done;
}
ret = qemu_rbd_next_tok(snap, snap_len, p, ':', "snap name", &p);
qemu_rbd_unescape(snap);
} else {
ret = qemu_rbd_next_tok(name, name_len, p, ':', "object name", &p);
}
qemu_rbd_unescape(name);
if (ret < 0 || !p) {
goto done;
}
ret = qemu_rbd_next_tok(conf, conf_len, p, '\0', "configuration", &p);
done:
g_free(buf);
return ret;
}
static char *qemu_rbd_parse_clientname(const char *conf, char *clientname)
{
const char *p = conf;
while (*p) {
int len;
const char *end = strchr(p, ':');
if (end) {
len = end - p;
} else {
len = strlen(p);
}
if (strncmp(p, "id=", 3) == 0) {
len -= 3;
strncpy(clientname, p + 3, len);
clientname[len] = '\0';
return clientname;
}
if (end == NULL) {
break;
}
p = end + 1;
}
return NULL;
}
static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
{
char *p, *buf;
char name[RBD_MAX_CONF_NAME_SIZE];
char value[RBD_MAX_CONF_VAL_SIZE];
int ret = 0;
buf = g_strdup(conf);
p = buf;
while (p) {
ret = qemu_rbd_next_tok(name, sizeof(name), p,
'=', "conf option name", &p);
if (ret < 0) {
break;
}
qemu_rbd_unescape(name);
if (!p) {
error_report("conf option %s has no value", name);
ret = -EINVAL;
break;
}
ret = qemu_rbd_next_tok(value, sizeof(value), p,
':', "conf option value", &p);
if (ret < 0) {
break;
}
qemu_rbd_unescape(value);
if (strcmp(name, "conf") == 0) {
ret = rados_conf_read_file(cluster, value);
if (ret < 0) {
error_report("error reading conf file %s", value);
break;
}
} else if (strcmp(name, "id") == 0) {
/* ignore, this is parsed by qemu_rbd_parse_clientname() */
} else {
ret = rados_conf_set(cluster, name, value);
if (ret < 0) {
error_report("invalid conf option %s", name);
ret = -EINVAL;
break;
}
}
}
g_free(buf);
return ret;
}
static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options)
{
int64_t bytes = 0;
int64_t objsize;
int obj_order = 0;
char pool[RBD_MAX_POOL_NAME_SIZE];
char name[RBD_MAX_IMAGE_NAME_SIZE];
char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
char conf[RBD_MAX_CONF_SIZE];
char clientname_buf[RBD_MAX_CONF_SIZE];
char *clientname;
rados_t cluster;
rados_ioctx_t io_ctx;
int ret;
if (qemu_rbd_parsename(filename, pool, sizeof(pool),
snap_buf, sizeof(snap_buf),
name, sizeof(name),
conf, sizeof(conf)) < 0) {
return -EINVAL;
}
/* Read out options */
while (options && options->name) {
if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
bytes = options->value.n;
} else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
if (options->value.n) {
objsize = options->value.n;
if ((objsize - 1) & objsize) { /* not a power of 2? */
error_report("obj size needs to be power of 2");
return -EINVAL;
}
if (objsize < 4096) {
error_report("obj size too small");
return -EINVAL;
}
obj_order = ffs(objsize) - 1;
}
}
options++;
}
clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
if (rados_create(&cluster, clientname) < 0) {
error_report("error initializing");
return -EIO;
}
if (strstr(conf, "conf=") == NULL) {
/* try default location, but ignore failure */
rados_conf_read_file(cluster, NULL);
}
if (conf[0] != '\0' &&
qemu_rbd_set_conf(cluster, conf) < 0) {
error_report("error setting config options");
rados_shutdown(cluster);
return -EIO;
}
if (rados_connect(cluster) < 0) {
error_report("error connecting");
rados_shutdown(cluster);
return -EIO;
}
if (rados_ioctx_create(cluster, pool, &io_ctx) < 0) {
error_report("error opening pool %s", pool);
rados_shutdown(cluster);
return -EIO;
}
ret = rbd_create(io_ctx, name, bytes, &obj_order);
rados_ioctx_destroy(io_ctx);
rados_shutdown(cluster);
return ret;
}
/*
* This aio completion is being called from qemu_rbd_aio_event_reader()
* and runs in qemu context. It schedules a bh, but just in case the aio
* was not cancelled before.
*/
static void qemu_rbd_complete_aio(RADOSCB *rcb)
{
RBDAIOCB *acb = rcb->acb;
int64_t r;
r = rcb->ret;
if (acb->cmd != RBD_AIO_READ) {
if (r < 0) {
acb->ret = r;
acb->error = 1;
} else if (!acb->error) {
acb->ret = rcb->size;
}
} else {
if (r < 0) {
memset(rcb->buf, 0, rcb->size);
acb->ret = r;
acb->error = 1;
} else if (r < rcb->size) {
memset(rcb->buf + r, 0, rcb->size - r);
if (!acb->error) {
acb->ret = rcb->size;
}
} else if (!acb->error) {
acb->ret = r;
}
}
/* Note that acb->bh can be NULL in case where the aio was cancelled */
acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb);
qemu_bh_schedule(acb->bh);
g_free(rcb);
}
/*
* aio fd read handler. It runs in the qemu context and calls the
* completion handling of completed rados aio operations.
*/
static void qemu_rbd_aio_event_reader(void *opaque)
{
BDRVRBDState *s = opaque;
ssize_t ret;
do {
char *p = (char *)&s->event_rcb;
/* now read the rcb pointer that was sent from a non qemu thread */
ret = read(s->fds[RBD_FD_READ], p + s->event_reader_pos,
sizeof(s->event_rcb) - s->event_reader_pos);
if (ret > 0) {
s->event_reader_pos += ret;
if (s->event_reader_pos == sizeof(s->event_rcb)) {
s->event_reader_pos = 0;
qemu_rbd_complete_aio(s->event_rcb);
s->qemu_aio_count--;
}
}
} while (ret < 0 && errno == EINTR);
}
static int qemu_rbd_aio_flush_cb(void *opaque)
{
BDRVRBDState *s = opaque;
return (s->qemu_aio_count > 0);
}
static int qemu_rbd_open(BlockDriverState *bs, const char *filename,
QDict *options, int flags)
{
BDRVRBDState *s = bs->opaque;
char pool[RBD_MAX_POOL_NAME_SIZE];
char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
char conf[RBD_MAX_CONF_SIZE];
char clientname_buf[RBD_MAX_CONF_SIZE];
char *clientname;
int r;
if (qemu_rbd_parsename(filename, pool, sizeof(pool),
snap_buf, sizeof(snap_buf),
s->name, sizeof(s->name),
conf, sizeof(conf)) < 0) {
return -EINVAL;
}
clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
r = rados_create(&s->cluster, clientname);
if (r < 0) {
error_report("error initializing");
return r;
}
s->snap = NULL;
if (snap_buf[0] != '\0') {
s->snap = g_strdup(snap_buf);
}
/*
* Fallback to more conservative semantics if setting cache
* options fails. Ignore errors from setting rbd_cache because the
* only possible error is that the option does not exist, and
* librbd defaults to no caching. If write through caching cannot
* be set up, fall back to no caching.
*/
if (flags & BDRV_O_NOCACHE) {
rados_conf_set(s->cluster, "rbd_cache", "false");
} else {
rados_conf_set(s->cluster, "rbd_cache", "true");
}
if (strstr(conf, "conf=") == NULL) {
/* try default location, but ignore failure */
rados_conf_read_file(s->cluster, NULL);
}
if (conf[0] != '\0') {
r = qemu_rbd_set_conf(s->cluster, conf);
if (r < 0) {
error_report("error setting config options");
goto failed_shutdown;
}
}
r = rados_connect(s->cluster);
if (r < 0) {
error_report("error connecting");
goto failed_shutdown;
}
r = rados_ioctx_create(s->cluster, pool, &s->io_ctx);
if (r < 0) {
error_report("error opening pool %s", pool);
goto failed_shutdown;
}
r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
if (r < 0) {
error_report("error reading header from %s", s->name);
goto failed_open;
}
bs->read_only = (s->snap != NULL);
s->event_reader_pos = 0;
r = qemu_pipe(s->fds);
if (r < 0) {
error_report("error opening eventfd");
goto failed;
}
fcntl(s->fds[0], F_SETFL, O_NONBLOCK);
fcntl(s->fds[1], F_SETFL, O_NONBLOCK);
qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], qemu_rbd_aio_event_reader,
NULL, qemu_rbd_aio_flush_cb, s);
return 0;
failed:
rbd_close(s->image);
failed_open:
rados_ioctx_destroy(s->io_ctx);
failed_shutdown:
rados_shutdown(s->cluster);
g_free(s->snap);
return r;
}
static void qemu_rbd_close(BlockDriverState *bs)
{
BDRVRBDState *s = bs->opaque;
close(s->fds[0]);
close(s->fds[1]);
qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], NULL, NULL, NULL, NULL);
rbd_close(s->image);
rados_ioctx_destroy(s->io_ctx);
g_free(s->snap);
rados_shutdown(s->cluster);
}
/*
* Cancel aio. Since we don't reference acb in a non qemu threads,
* it is safe to access it here.
*/
static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb)
{
RBDAIOCB *acb = (RBDAIOCB *) blockacb;
acb->cancelled = 1;
while (acb->status == -EINPROGRESS) {
qemu_aio_wait();
}
qemu_aio_release(acb);
}
static const AIOCBInfo rbd_aiocb_info = {
.aiocb_size = sizeof(RBDAIOCB),
.cancel = qemu_rbd_aio_cancel,
};
static int qemu_rbd_send_pipe(BDRVRBDState *s, RADOSCB *rcb)
{
int ret = 0;
while (1) {
fd_set wfd;
int fd = s->fds[RBD_FD_WRITE];
/* send the op pointer to the qemu thread that is responsible
for the aio/op completion. Must do it in a qemu thread context */
ret = write(fd, (void *)&rcb, sizeof(rcb));
if (ret >= 0) {
break;
}
if (errno == EINTR) {
continue;
}
if (errno != EAGAIN) {
break;
}
FD_ZERO(&wfd);
FD_SET(fd, &wfd);
do {
ret = select(fd + 1, NULL, &wfd, NULL, NULL);
} while (ret < 0 && errno == EINTR);
}
return ret;
}
/*
* This is the callback function for rbd_aio_read and _write
*
* Note: this function is being called from a non qemu thread so
* we need to be careful about what we do here. Generally we only
* write to the block notification pipe, and do the rest of the
* io completion handling from qemu_rbd_aio_event_reader() which
* runs in a qemu context.
*/
static void rbd_finish_aiocb(rbd_completion_t c, RADOSCB *rcb)
{
int ret;
rcb->ret = rbd_aio_get_return_value(c);
rbd_aio_release(c);
ret = qemu_rbd_send_pipe(rcb->s, rcb);
if (ret < 0) {
error_report("failed writing to acb->s->fds");
g_free(rcb);
}
}
/* Callback when all queued rbd_aio requests are complete */
static void rbd_aio_bh_cb(void *opaque)
{
RBDAIOCB *acb = opaque;
if (acb->cmd == RBD_AIO_READ) {
qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
}
qemu_vfree(acb->bounce);
acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
qemu_bh_delete(acb->bh);
acb->bh = NULL;
acb->status = 0;
if (!acb->cancelled) {
qemu_aio_release(acb);
}
}
static int rbd_aio_discard_wrapper(rbd_image_t image,
uint64_t off,
uint64_t len,
rbd_completion_t comp)
{
#ifdef LIBRBD_SUPPORTS_DISCARD
return rbd_aio_discard(image, off, len, comp);
#else
return -ENOTSUP;
#endif
}
static int rbd_aio_flush_wrapper(rbd_image_t image,
rbd_completion_t comp)
{
#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
return rbd_aio_flush(image, comp);
#else
return -ENOTSUP;
#endif
}
static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque,
RBDAIOCmd cmd)
{
RBDAIOCB *acb;
RADOSCB *rcb;
rbd_completion_t c;
int64_t off, size;
char *buf;
int r;
BDRVRBDState *s = bs->opaque;
acb = qemu_aio_get(&rbd_aiocb_info, bs, cb, opaque);
acb->cmd = cmd;
acb->qiov = qiov;
if (cmd == RBD_AIO_DISCARD || cmd == RBD_AIO_FLUSH) {
acb->bounce = NULL;
} else {
acb->bounce = qemu_blockalign(bs, qiov->size);
}
acb->ret = 0;
acb->error = 0;
acb->s = s;
acb->cancelled = 0;
acb->bh = NULL;
acb->status = -EINPROGRESS;
if (cmd == RBD_AIO_WRITE) {
qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
}
buf = acb->bounce;
off = sector_num * BDRV_SECTOR_SIZE;
size = nb_sectors * BDRV_SECTOR_SIZE;
s->qemu_aio_count++; /* All the RADOSCB */
rcb = g_malloc(sizeof(RADOSCB));
rcb->done = 0;
rcb->acb = acb;
rcb->buf = buf;
rcb->s = acb->s;
rcb->size = size;
r = rbd_aio_create_completion(rcb, (rbd_callback_t) rbd_finish_aiocb, &c);
if (r < 0) {
goto failed;
}
switch (cmd) {
case RBD_AIO_WRITE:
r = rbd_aio_write(s->image, off, size, buf, c);
break;
case RBD_AIO_READ:
r = rbd_aio_read(s->image, off, size, buf, c);
break;
case RBD_AIO_DISCARD:
r = rbd_aio_discard_wrapper(s->image, off, size, c);
break;
case RBD_AIO_FLUSH:
r = rbd_aio_flush_wrapper(s->image, c);
break;
default:
r = -EINVAL;
}
if (r < 0) {
goto failed;
}
return &acb->common;
failed:
g_free(rcb);
s->qemu_aio_count--;
qemu_aio_release(acb);
return NULL;
}
static BlockDriverAIOCB *qemu_rbd_aio_readv(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
RBD_AIO_READ);
}
static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
RBD_AIO_WRITE);
}
#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
static BlockDriverAIOCB *qemu_rbd_aio_flush(BlockDriverState *bs,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return rbd_start_aio(bs, 0, NULL, 0, cb, opaque, RBD_AIO_FLUSH);
}
#else
static int qemu_rbd_co_flush(BlockDriverState *bs)
{
#if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 1)
/* rbd_flush added in 0.1.1 */
BDRVRBDState *s = bs->opaque;
return rbd_flush(s->image);
#else
return 0;
#endif
}
#endif
static int qemu_rbd_getinfo(BlockDriverState *bs, BlockDriverInfo *bdi)
{
BDRVRBDState *s = bs->opaque;
rbd_image_info_t info;
int r;
r = rbd_stat(s->image, &info, sizeof(info));
if (r < 0) {
return r;
}
bdi->cluster_size = info.obj_size;
return 0;
}
static int64_t qemu_rbd_getlength(BlockDriverState *bs)
{
BDRVRBDState *s = bs->opaque;
rbd_image_info_t info;
int r;
r = rbd_stat(s->image, &info, sizeof(info));
if (r < 0) {
return r;
}
return info.size;
}
static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
{
BDRVRBDState *s = bs->opaque;
int r;
r = rbd_resize(s->image, offset);
if (r < 0) {
return r;
}
return 0;
}
static int qemu_rbd_snap_create(BlockDriverState *bs,
QEMUSnapshotInfo *sn_info)
{
BDRVRBDState *s = bs->opaque;
int r;
if (sn_info->name[0] == '\0') {
return -EINVAL; /* we need a name for rbd snapshots */
}
/*
* rbd snapshots are using the name as the user controlled unique identifier
* we can't use the rbd snapid for that purpose, as it can't be set
*/
if (sn_info->id_str[0] != '\0' &&
strcmp(sn_info->id_str, sn_info->name) != 0) {
return -EINVAL;
}
if (strlen(sn_info->name) >= sizeof(sn_info->id_str)) {
return -ERANGE;
}
r = rbd_snap_create(s->image, sn_info->name);
if (r < 0) {
error_report("failed to create snap: %s", strerror(-r));
return r;
}
return 0;
}
static int qemu_rbd_snap_remove(BlockDriverState *bs,
const char *snapshot_name)
{
BDRVRBDState *s = bs->opaque;
int r;
r = rbd_snap_remove(s->image, snapshot_name);
return r;
}
static int qemu_rbd_snap_rollback(BlockDriverState *bs,
const char *snapshot_name)
{
BDRVRBDState *s = bs->opaque;
int r;
r = rbd_snap_rollback(s->image, snapshot_name);
return r;
}
static int qemu_rbd_snap_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_tab)
{
BDRVRBDState *s = bs->opaque;
QEMUSnapshotInfo *sn_info, *sn_tab = NULL;
int i, snap_count;
rbd_snap_info_t *snaps;
int max_snaps = RBD_MAX_SNAPS;
do {
snaps = g_malloc(sizeof(*snaps) * max_snaps);
snap_count = rbd_snap_list(s->image, snaps, &max_snaps);
if (snap_count < 0) {
g_free(snaps);
}
} while (snap_count == -ERANGE);
if (snap_count <= 0) {
goto done;
}
sn_tab = g_malloc0(snap_count * sizeof(QEMUSnapshotInfo));
for (i = 0; i < snap_count; i++) {
const char *snap_name = snaps[i].name;
sn_info = sn_tab + i;
pstrcpy(sn_info->id_str, sizeof(sn_info->id_str), snap_name);
pstrcpy(sn_info->name, sizeof(sn_info->name), snap_name);
sn_info->vm_state_size = snaps[i].size;
sn_info->date_sec = 0;
sn_info->date_nsec = 0;
sn_info->vm_clock_nsec = 0;
}
rbd_snap_list_end(snaps);
done:
*psn_tab = sn_tab;
return snap_count;
}
#ifdef LIBRBD_SUPPORTS_DISCARD
static BlockDriverAIOCB* qemu_rbd_aio_discard(BlockDriverState *bs,
int64_t sector_num,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return rbd_start_aio(bs, sector_num, NULL, nb_sectors, cb, opaque,
RBD_AIO_DISCARD);
}
#endif
static QEMUOptionParameter qemu_rbd_create_options[] = {
{
.name = BLOCK_OPT_SIZE,
.type = OPT_SIZE,
.help = "Virtual disk size"
},
{
.name = BLOCK_OPT_CLUSTER_SIZE,
.type = OPT_SIZE,
.help = "RBD object size"
},
{NULL}
};
static BlockDriver bdrv_rbd = {
.format_name = "rbd",
.instance_size = sizeof(BDRVRBDState),
.bdrv_file_open = qemu_rbd_open,
.bdrv_close = qemu_rbd_close,
.bdrv_create = qemu_rbd_create,
.bdrv_get_info = qemu_rbd_getinfo,
.create_options = qemu_rbd_create_options,
.bdrv_getlength = qemu_rbd_getlength,
.bdrv_truncate = qemu_rbd_truncate,
.protocol_name = "rbd",
.bdrv_aio_readv = qemu_rbd_aio_readv,
.bdrv_aio_writev = qemu_rbd_aio_writev,
#ifdef LIBRBD_SUPPORTS_AIO_FLUSH
.bdrv_aio_flush = qemu_rbd_aio_flush,
#else
.bdrv_co_flush_to_disk = qemu_rbd_co_flush,
#endif
#ifdef LIBRBD_SUPPORTS_DISCARD
.bdrv_aio_discard = qemu_rbd_aio_discard,
#endif
.bdrv_snapshot_create = qemu_rbd_snap_create,
.bdrv_snapshot_delete = qemu_rbd_snap_remove,
.bdrv_snapshot_list = qemu_rbd_snap_list,
.bdrv_snapshot_goto = qemu_rbd_snap_rollback,
};
static void bdrv_rbd_init(void)
{
bdrv_register(&bdrv_rbd);
}
block_init(bdrv_rbd_init);
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