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xemu/block/rbd.c
Christian Brunner f27aaf4b53 ceph/rbd block driver for qemu-kvm 
RBD is an block driver for the distributed file system Ceph
(http://ceph.newdream.net/). This driver uses librados (which is part
of the Ceph server) for direct access to the Ceph object store and is
running entirely in userspace (Yehuda also wrote a driver for the
linux kernel, that can be used to access rbd volumes as a block
device).

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Christian Brunner <chb@muc.de>
Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2010-12-14 15:44:21 +01:00

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/*
* QEMU Block driver for RADOS (Ceph)
*
* Copyright (C) 2010 Christian Brunner <chb@muc.de>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu-common.h"
#include "qemu-error.h"
#include "rbd_types.h"
#include "block_int.h"
#include <rados/librados.h>
/*
* When specifying the image filename use:
*
* rbd:poolname/devicename
*
* poolname must be the name of an existing rados pool
*
* devicename is the basename for all objects used to
* emulate the raw device.
*
* Metadata information (image size, ...) is stored in an
* object with the name "devicename.rbd".
*
* The raw device is split into 4MB sized objects by default.
* The sequencenumber is encoded in a 12 byte long hex-string,
* and is attached to the devicename, separated by a dot.
* e.g. "devicename.1234567890ab"
*
*/
#define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
typedef struct RBDAIOCB {
BlockDriverAIOCB common;
QEMUBH *bh;
int ret;
QEMUIOVector *qiov;
char *bounce;
int write;
int64_t sector_num;
int aiocnt;
int error;
struct BDRVRBDState *s;
int cancelled;
} RBDAIOCB;
typedef struct RADOSCB {
int rcbid;
RBDAIOCB *acb;
struct BDRVRBDState *s;
int done;
int64_t segsize;
char *buf;
int ret;
} RADOSCB;
#define RBD_FD_READ 0
#define RBD_FD_WRITE 1
typedef struct BDRVRBDState {
int fds[2];
rados_pool_t pool;
rados_pool_t header_pool;
char name[RBD_MAX_OBJ_NAME_SIZE];
char block_name[RBD_MAX_BLOCK_NAME_SIZE];
uint64_t size;
uint64_t objsize;
int qemu_aio_count;
int event_reader_pos;
RADOSCB *event_rcb;
} BDRVRBDState;
typedef struct rbd_obj_header_ondisk RbdHeader1;
static void rbd_aio_bh_cb(void *opaque);
static int 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') {
end = strchr(src, delim);
if (end) {
*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 int rbd_parsename(const char *filename,
char *pool, int pool_len,
char *snap, int snap_len,
char *name, int name_len)
{
const char *start;
char *p, *buf;
int ret;
if (!strstart(filename, "rbd:", &start)) {
return -EINVAL;
}
buf = qemu_strdup(start);
p = buf;
ret = rbd_next_tok(pool, pool_len, p, '/', "pool name", &p);
if (ret < 0 || !p) {
ret = -EINVAL;
goto done;
}
ret = rbd_next_tok(name, name_len, p, '@', "object name", &p);
if (ret < 0) {
goto done;
}
if (!p) {
*snap = '\0';
goto done;
}
ret = rbd_next_tok(snap, snap_len, p, '\0', "snap name", &p);
done:
qemu_free(buf);
return ret;
}
static int create_tmap_op(uint8_t op, const char *name, char **tmap_desc)
{
uint32_t len = strlen(name);
uint32_t len_le = cpu_to_le32(len);
/* total_len = encoding op + name + empty buffer */
uint32_t total_len = 1 + (sizeof(uint32_t) + len) + sizeof(uint32_t);
uint8_t *desc = NULL;
desc = qemu_malloc(total_len);
*tmap_desc = (char *)desc;
*desc = op;
desc++;
memcpy(desc, &len_le, sizeof(len_le));
desc += sizeof(len_le);
memcpy(desc, name, len);
desc += len;
len = 0; /* no need for endian conversion for 0 */
memcpy(desc, &len, sizeof(len));
desc += sizeof(len);
return (char *)desc - *tmap_desc;
}
static void free_tmap_op(char *tmap_desc)
{
qemu_free(tmap_desc);
}
static int rbd_register_image(rados_pool_t pool, const char *name)
{
char *tmap_desc;
const char *dir = RBD_DIRECTORY;
int ret;
ret = create_tmap_op(CEPH_OSD_TMAP_SET, name, &tmap_desc);
if (ret < 0) {
return ret;
}
ret = rados_tmap_update(pool, dir, tmap_desc, ret);
free_tmap_op(tmap_desc);
return ret;
}
static int touch_rbd_info(rados_pool_t pool, const char *info_oid)
{
int r = rados_write(pool, info_oid, 0, NULL, 0);
if (r < 0) {
return r;
}
return 0;
}
static int rbd_assign_bid(rados_pool_t pool, uint64_t *id)
{
uint64_t out[1];
const char *info_oid = RBD_INFO;
*id = 0;
int r = touch_rbd_info(pool, info_oid);
if (r < 0) {
return r;
}
r = rados_exec(pool, info_oid, "rbd", "assign_bid", NULL,
0, (char *)out, sizeof(out));
if (r < 0) {
return r;
}
le64_to_cpus(out);
*id = out[0];
return 0;
}
static int rbd_create(const char *filename, QEMUOptionParameter *options)
{
int64_t bytes = 0;
int64_t objsize;
uint64_t size;
time_t mtime;
uint8_t obj_order = RBD_DEFAULT_OBJ_ORDER;
char pool[RBD_MAX_SEG_NAME_SIZE];
char n[RBD_MAX_SEG_NAME_SIZE];
char name[RBD_MAX_OBJ_NAME_SIZE];
char snap_buf[RBD_MAX_SEG_NAME_SIZE];
char *snap = NULL;
RbdHeader1 header;
rados_pool_t p;
uint64_t bid;
uint32_t hi, lo;
int ret;
if (rbd_parsename(filename,
pool, sizeof(pool),
snap_buf, sizeof(snap_buf),
name, sizeof(name)) < 0) {
return -EINVAL;
}
if (snap_buf[0] != '\0') {
snap = snap_buf;
}
snprintf(n, sizeof(n), "%s%s", name, RBD_SUFFIX);
/* 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++;
}
memset(&header, 0, sizeof(header));
pstrcpy(header.text, sizeof(header.text), RBD_HEADER_TEXT);
pstrcpy(header.signature, sizeof(header.signature), RBD_HEADER_SIGNATURE);
pstrcpy(header.version, sizeof(header.version), RBD_HEADER_VERSION);
header.image_size = cpu_to_le64(bytes);
header.options.order = obj_order;
header.options.crypt_type = RBD_CRYPT_NONE;
header.options.comp_type = RBD_COMP_NONE;
header.snap_seq = 0;
header.snap_count = 0;
if (rados_initialize(0, NULL) < 0) {
error_report("error initializing");
return -EIO;
}
if (rados_open_pool(pool, &p)) {
error_report("error opening pool %s", pool);
rados_deinitialize();
return -EIO;
}
/* check for existing rbd header file */
ret = rados_stat(p, n, &size, &mtime);
if (ret == 0) {
ret=-EEXIST;
goto done;
}
ret = rbd_assign_bid(p, &bid);
if (ret < 0) {
error_report("failed assigning block id");
rados_deinitialize();
return -EIO;
}
hi = bid >> 32;
lo = bid & 0xFFFFFFFF;
snprintf(header.block_name, sizeof(header.block_name), "rb.%x.%x", hi, lo);
/* create header file */
ret = rados_write(p, n, 0, (const char *)&header, sizeof(header));
if (ret < 0) {
goto done;
}
ret = rbd_register_image(p, name);
done:
rados_close_pool(p);
rados_deinitialize();
return ret;
}
/*
* This aio completion is being called from 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 rbd_complete_aio(RADOSCB *rcb)
{
RBDAIOCB *acb = rcb->acb;
int64_t r;
acb->aiocnt--;
if (acb->cancelled) {
if (!acb->aiocnt) {
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->segsize;
}
} else {
if (r == -ENOENT) {
memset(rcb->buf, 0, rcb->segsize);
if (!acb->error) {
acb->ret += rcb->segsize;
}
} else if (r < 0) {
memset(rcb->buf, 0, rcb->segsize);
acb->ret = r;
acb->error = 1;
} else if (r < rcb->segsize) {
memset(rcb->buf + r, 0, rcb->segsize - r);
if (!acb->error) {
acb->ret += rcb->segsize;
}
} else if (!acb->error) {
acb->ret += r;
}
}
/* Note that acb->bh can be NULL in case where the aio was cancelled */
if (!acb->aiocnt) {
acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb);
qemu_bh_schedule(acb->bh);
}
done:
qemu_free(rcb);
}
/*
* aio fd read handler. It runs in the qemu context and calls the
* completion handling of completed rados aio operations.
*/
static void 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 */
if ((ret = read(s->fds[RBD_FD_READ], p + s->event_reader_pos,
sizeof(s->event_rcb) - s->event_reader_pos)) > 0) {
if (ret > 0) {
s->event_reader_pos += ret;
if (s->event_reader_pos == sizeof(s->event_rcb)) {
s->event_reader_pos = 0;
rbd_complete_aio(s->event_rcb);
s->qemu_aio_count --;
}
}
}
} while (ret < 0 && errno == EINTR);
}
static int rbd_aio_flush_cb(void *opaque)
{
BDRVRBDState *s = opaque;
return (s->qemu_aio_count > 0);
}
static int rbd_set_snapc(rados_pool_t pool, const char *snap, RbdHeader1 *header)
{
uint32_t snap_count = le32_to_cpu(header->snap_count);
rados_snap_t *snaps = NULL;
rados_snap_t seq;
uint32_t i;
uint64_t snap_names_len = le64_to_cpu(header->snap_names_len);
int r;
rados_snap_t snapid = 0;
if (snap_count) {
const char *header_snap = (const char *)&header->snaps[snap_count];
const char *end = header_snap + snap_names_len;
snaps = qemu_malloc(sizeof(rados_snap_t) * header->snap_count);
for (i=0; i < snap_count; i++) {
snaps[i] = le64_to_cpu(header->snaps[i].id);
if (snap && strcmp(snap, header_snap) == 0) {
snapid = snaps[i];
}
header_snap += strlen(header_snap) + 1;
if (header_snap > end) {
error_report("bad header, snapshot list broken");
}
}
}
if (snap && !snapid) {
error_report("snapshot not found");
qemu_free(snaps);
return -ENOENT;
}
seq = le32_to_cpu(header->snap_seq);
r = rados_set_snap_context(pool, seq, snaps, snap_count);
rados_set_snap(pool, snapid);
qemu_free(snaps);
return r;
}
#define BUF_READ_START_LEN 4096
static int rbd_read_header(BDRVRBDState *s, char **hbuf)
{
char *buf = NULL;
char n[RBD_MAX_SEG_NAME_SIZE];
uint64_t len = BUF_READ_START_LEN;
int r;
snprintf(n, sizeof(n), "%s%s", s->name, RBD_SUFFIX);
buf = qemu_malloc(len);
r = rados_read(s->header_pool, n, 0, buf, len);
if (r < 0) {
goto failed;
}
if (r < len) {
goto done;
}
qemu_free(buf);
buf = qemu_malloc(len);
r = rados_stat(s->header_pool, n, &len, NULL);
if (r < 0) {
goto failed;
}
r = rados_read(s->header_pool, n, 0, buf, len);
if (r < 0) {
goto failed;
}
done:
*hbuf = buf;
return 0;
failed:
qemu_free(buf);
return r;
}
static int rbd_open(BlockDriverState *bs, const char *filename, int flags)
{
BDRVRBDState *s = bs->opaque;
RbdHeader1 *header;
char pool[RBD_MAX_SEG_NAME_SIZE];
char snap_buf[RBD_MAX_SEG_NAME_SIZE];
char *snap = NULL;
char *hbuf = NULL;
int r;
if (rbd_parsename(filename, pool, sizeof(pool),
snap_buf, sizeof(snap_buf),
s->name, sizeof(s->name)) < 0) {
return -EINVAL;
}
if (snap_buf[0] != '\0') {
snap = snap_buf;
}
if ((r = rados_initialize(0, NULL)) < 0) {
error_report("error initializing");
return r;
}
if ((r = rados_open_pool(pool, &s->pool))) {
error_report("error opening pool %s", pool);
rados_deinitialize();
return r;
}
if ((r = rados_open_pool(pool, &s->header_pool))) {
error_report("error opening pool %s", pool);
rados_deinitialize();
return r;
}
if ((r = rbd_read_header(s, &hbuf)) < 0) {
error_report("error reading header from %s", s->name);
goto failed;
}
if (memcmp(hbuf + 64, RBD_HEADER_SIGNATURE, 4)) {
error_report("Invalid header signature");
r = -EMEDIUMTYPE;
goto failed;
}
if (memcmp(hbuf + 68, RBD_HEADER_VERSION, 8)) {
error_report("Unknown image version");
r = -EMEDIUMTYPE;
goto failed;
}
header = (RbdHeader1 *) hbuf;
s->size = le64_to_cpu(header->image_size);
s->objsize = 1ULL << header->options.order;
memcpy(s->block_name, header->block_name, sizeof(header->block_name));
r = rbd_set_snapc(s->pool, snap, header);
if (r < 0) {
error_report("failed setting snap context: %s", strerror(-r));
goto failed;
}
bs->read_only = (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], rbd_aio_event_reader, NULL,
rbd_aio_flush_cb, NULL, s);
qemu_free(hbuf);
return 0;
failed:
qemu_free(hbuf);
rados_close_pool(s->header_pool);
rados_close_pool(s->pool);
rados_deinitialize();
return r;
}
static void 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);
rados_close_pool(s->header_pool);
rados_close_pool(s->pool);
rados_deinitialize();
}
/*
* Cancel aio. Since we don't reference acb in a non qemu threads,
* it is safe to access it here.
*/
static void rbd_aio_cancel(BlockDriverAIOCB *blockacb)
{
RBDAIOCB *acb = (RBDAIOCB *) blockacb;
acb->cancelled = 1;
}
static AIOPool rbd_aio_pool = {
.aiocb_size = sizeof(RBDAIOCB),
.cancel = rbd_aio_cancel,
};
/*
* This is the callback function for rados_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 rbd_aio_event_reader() which
* runs in a qemu context.
*/
static void rbd_finish_aiocb(rados_completion_t c, RADOSCB *rcb)
{
int ret;
rcb->ret = rados_aio_get_return_value(c);
rados_aio_release(c);
while (1) {
fd_set wfd;
int fd = rcb->s->fds[RBD_FD_WRITE];
/* send the rcb pointer to the qemu thread that is responsible
for the aio 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);
}
if (ret < 0) {
error_report("failed writing to acb->s->fds\n");
qemu_free(rcb);
}
}
/* Callback when all queued rados_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;
rados_completion_t c;
char n[RBD_MAX_SEG_NAME_SIZE];
int64_t segnr, segoffs, segsize, last_segnr;
int64_t off, size;
char *buf;
BDRVRBDState *s = bs->opaque;
acb = qemu_aio_get(&rbd_aio_pool, bs, cb, opaque);
acb->write = write;
acb->qiov = qiov;
acb->bounce = qemu_blockalign(bs, qiov->size);
acb->aiocnt = 0;
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;
segnr = off / s->objsize;
segoffs = off % s->objsize;
segsize = s->objsize - segoffs;
last_segnr = ((off + size - 1) / s->objsize);
acb->aiocnt = (last_segnr - segnr) + 1;
s->qemu_aio_count += acb->aiocnt; /* All the RADOSCB */
while (size > 0) {
if (size < segsize) {
segsize = size;
}
snprintf(n, sizeof(n), "%s.%012" PRIx64, s->block_name,
segnr);
rcb = qemu_malloc(sizeof(RADOSCB));
rcb->done = 0;
rcb->acb = acb;
rcb->segsize = segsize;
rcb->buf = buf;
rcb->s = acb->s;
if (write) {
rados_aio_create_completion(rcb, NULL,
(rados_callback_t) rbd_finish_aiocb,
&c);
rados_aio_write(s->pool, n, segoffs, buf, segsize, c);
} else {
rados_aio_create_completion(rcb,
(rados_callback_t) rbd_finish_aiocb,
NULL, &c);
rados_aio_read(s->pool, n, segoffs, buf, segsize, c);
}
buf += segsize;
size -= segsize;
segoffs = 0;
segsize = s->objsize;
segnr++;
}
return &acb->common;
}
static BlockDriverAIOCB *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 *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 rbd_getinfo(BlockDriverState * bs, BlockDriverInfo * bdi)
{
BDRVRBDState *s = bs->opaque;
bdi->cluster_size = s->objsize;
return 0;
}
static int64_t rbd_getlength(BlockDriverState * bs)
{
BDRVRBDState *s = bs->opaque;
return s->size;
}
static int rbd_snap_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
{
BDRVRBDState *s = bs->opaque;
char inbuf[512], outbuf[128];
uint64_t snap_id;
int r;
char *p = inbuf;
char *end = inbuf + sizeof(inbuf);
char n[RBD_MAX_SEG_NAME_SIZE];
char *hbuf = NULL;
RbdHeader1 *header;
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 = rados_selfmanaged_snap_create(s->header_pool, &snap_id);
if (r < 0) {
error_report("failed to create snap id: %s", strerror(-r));
return r;
}
*(uint32_t *)p = strlen(sn_info->name);
cpu_to_le32s((uint32_t *)p);
p += sizeof(uint32_t);
strncpy(p, sn_info->name, end - p);
p += strlen(p);
if (p + sizeof(snap_id) > end) {
error_report("invalid input parameter");
return -EINVAL;
}
*(uint64_t *)p = snap_id;
cpu_to_le64s((uint64_t *)p);
snprintf(n, sizeof(n), "%s%s", s->name, RBD_SUFFIX);
r = rados_exec(s->header_pool, n, "rbd", "snap_add", inbuf,
sizeof(inbuf), outbuf, sizeof(outbuf));
if (r < 0) {
error_report("rbd.snap_add execution failed failed: %s", strerror(-r));
return r;
}
sprintf(sn_info->id_str, "%s", sn_info->name);
r = rbd_read_header(s, &hbuf);
if (r < 0) {
error_report("failed reading header: %s", strerror(-r));
return r;
}
header = (RbdHeader1 *) hbuf;
r = rbd_set_snapc(s->pool, sn_info->name, header);
if (r < 0) {
error_report("failed setting snap context: %s", strerror(-r));
goto failed;
}
return 0;
failed:
qemu_free(header);
return r;
}
static int decode32(char **p, const char *end, uint32_t *v)
{
if (*p + 4 > end) {
return -ERANGE;
}
*v = *(uint32_t *)(*p);
le32_to_cpus(v);
*p += 4;
return 0;
}
static int decode64(char **p, const char *end, uint64_t *v)
{
if (*p + 8 > end) {
return -ERANGE;
}
*v = *(uint64_t *)(*p);
le64_to_cpus(v);
*p += 8;
return 0;
}
static int decode_str(char **p, const char *end, char **s)
{
uint32_t len;
int r;
if ((r = decode32(p, end, &len)) < 0) {
return r;
}
*s = qemu_malloc(len + 1);
memcpy(*s, *p, len);
*p += len;
(*s)[len] = '\0';
return len;
}
static int rbd_snap_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
{
BDRVRBDState *s = bs->opaque;
char n[RBD_MAX_SEG_NAME_SIZE];
QEMUSnapshotInfo *sn_info, *sn_tab = NULL;
RbdHeader1 *header;
char *hbuf = NULL;
char *outbuf = NULL, *end, *buf;
uint64_t len;
uint64_t snap_seq;
uint32_t snap_count;
int r, i;
/* read header to estimate how much space we need to read the snap
* list */
if ((r = rbd_read_header(s, &hbuf)) < 0) {
goto done_err;
}
header = (RbdHeader1 *)hbuf;
len = le64_to_cpu(header->snap_names_len);
len += 1024; /* should have already been enough, but new snapshots might
already been created since we read the header. just allocate
a bit more, so that in most cases it'll suffice anyway */
qemu_free(hbuf);
snprintf(n, sizeof(n), "%s%s", s->name, RBD_SUFFIX);
while (1) {
qemu_free(outbuf);
outbuf = qemu_malloc(len);
r = rados_exec(s->header_pool, n, "rbd", "snap_list", NULL, 0,
outbuf, len);
if (r < 0) {
error_report("rbd.snap_list execution failed failed: %s", strerror(-r));
goto done_err;
}
if (r != len) {
break;
}
/* if we're here, we probably raced with some snaps creation */
len *= 2;
}
buf = outbuf;
end = buf + len;
if ((r = decode64(&buf, end, &snap_seq)) < 0) {
goto done_err;
}
if ((r = decode32(&buf, end, &snap_count)) < 0) {
goto done_err;
}
sn_tab = qemu_mallocz(snap_count * sizeof(QEMUSnapshotInfo));
for (i = 0; i < snap_count; i++) {
uint64_t id, image_size;
char *snap_name;
if ((r = decode64(&buf, end, &id)) < 0) {
goto done_err;
}
if ((r = decode64(&buf, end, &image_size)) < 0) {
goto done_err;
}
if ((r = decode_str(&buf, end, &snap_name)) < 0) {
goto done_err;
}
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);
qemu_free(snap_name);
sn_info->vm_state_size = image_size;
sn_info->date_sec = 0;
sn_info->date_nsec = 0;
sn_info->vm_clock_nsec = 0;
}
*psn_tab = sn_tab;
qemu_free(outbuf);
return snap_count;
done_err:
qemu_free(sn_tab);
qemu_free(outbuf);
return r;
}
static QEMUOptionParameter 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 = rbd_open,
.bdrv_close = rbd_close,
.bdrv_create = rbd_create,
.bdrv_get_info = rbd_getinfo,
.create_options = rbd_create_options,
.bdrv_getlength = rbd_getlength,
.protocol_name = "rbd",
.bdrv_aio_readv = rbd_aio_readv,
.bdrv_aio_writev = rbd_aio_writev,
.bdrv_snapshot_create = rbd_snap_create,
.bdrv_snapshot_list = rbd_snap_list,
};
static void bdrv_rbd_init(void)
{
bdrv_register(&bdrv_rbd);
}
block_init(bdrv_rbd_init);
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