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qemu/block/rbd.c
Kevin Wolf c68b89acd6 block: Rename bdrv_co_flush to bdrv_co_flush_to_disk 
There are two different types of flush that you can do: Flushing one level up
to the OS (i.e. writing data to the host page cache) or flushing it all the way
down to the disk. The existing functions flush to the disk, reflect this in the
function name.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-11-11 14:02:59 +01:00

874 lines
22 KiB
C
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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.
*
*/
#include <inttypes.h>
#include "qemu-common.h"
#include "qemu-error.h"
#include "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 "\".
*/
#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 struct RBDAIOCB {
BlockDriverAIOCB common;
QEMUBH *bh;
int ret;
QEMUIOVector *qiov;
char *bounce;
int write;
int64_t sector_num;
int error;
struct BDRVRBDState *s;
int cancelled;
} RBDAIOCB;
typedef struct RADOSCB {
int rcbid;
RBDAIOCB *acb;
struct BDRVRBDState *s;
int done;
int64_t size;
char *buf;
int 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;
if (acb->cancelled) {
qemu_vfree(acb->bounce);
qemu_aio_release(acb);
goto done;
}
r = rcb->ret;
if (acb->write) {
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);
done:
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, 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);
}
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, NULL, 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,
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;
}
static AIOPool rbd_aio_pool = {
.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->write) {
qemu_iovec_from_buffer(acb->qiov, 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;
qemu_aio_release(acb);
}
static BlockDriverAIOCB *rbd_aio_rw_vector(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque, int write)
{
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_aio_pool, bs, cb, opaque);
if (!acb) {
return NULL;
}
acb->write = write;
acb->qiov = qiov;
acb->bounce = qemu_blockalign(bs, qiov->size);
acb->ret = 0;
acb->error = 0;
acb->s = s;
acb->cancelled = 0;
acb->bh = NULL;
if (write) {
qemu_iovec_to_buffer(acb->qiov, acb->bounce);
}
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;
}
if (write) {
r = rbd_aio_write(s->image, off, size, buf, c);
} else {
r = rbd_aio_read(s->image, off, size, buf, c);
}
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_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
}
static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
int64_t sector_num,
QEMUIOVector *qiov,
int nb_sectors,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return rbd_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
}
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
}
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_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) {
return snap_count;
}
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);
*psn_tab = sn_tab;
return snap_count;
}
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,
.bdrv_co_flush_to_disk = qemu_rbd_co_flush,
.bdrv_snapshot_create = qemu_rbd_snap_create,
.bdrv_snapshot_list = qemu_rbd_snap_list,
};
static void bdrv_rbd_init(void)
{
bdrv_register(&bdrv_rbd);
}
block_init(bdrv_rbd_init);
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