block/rbd.c

   1 /*
   2  * QEMU Block driver for RADOS (Ceph)
   3  *
   4  * Copyright (C) 2010-2011 Christian Brunner <chb@muc.de>,
   5  *                         Josh Durgin <josh.durgin@dreamhost.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2.  See
   8  * the COPYING file in the top-level directory.
   9  *
  10  * Contributions after 2012-01-13 are licensed under the terms of the
  11  * GNU GPL, version 2 or (at your option) any later version.
  12  */
  13
  14 #include <inttypes.h>
  15
  16 #include "qemu-common.h"
  17 #include "qemu-error.h"
  18 #include "block_int.h"
  19
  20 #include <rbd/librbd.h>
  21
  22 /*
  23  * When specifying the image filename use:
  24  *
  25  * rbd:poolname/devicename[@snapshotname][:option1=value1[:option2=value2...]]
  26  *
  27  * poolname must be the name of an existing rados pool.
  28  *
  29  * devicename is the name of the rbd image.
  30  *
  31  * Each option given is used to configure rados, and may be any valid
  32  * Ceph option, "id", or "conf".
  33  *
  34  * The "id" option indicates what user we should authenticate as to
  35  * the Ceph cluster.  If it is excluded we will use the Ceph default
  36  * (normally 'admin').
  37  *
  38  * The "conf" option specifies a Ceph configuration file to read.  If
  39  * it is not specified, we will read from the default Ceph locations
  40  * (e.g., /etc/ceph/ceph.conf).  To avoid reading _any_ configuration
  41  * file, specify conf=/dev/null.
  42  *
  43  * Configuration values containing :, @, or = can be escaped with a
  44  * leading "\".
  45  */
  46
  47 #define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
  48
  49 #define RBD_MAX_CONF_NAME_SIZE 128
  50 #define RBD_MAX_CONF_VAL_SIZE 512
  51 #define RBD_MAX_CONF_SIZE 1024
  52 #define RBD_MAX_POOL_NAME_SIZE 128
  53 #define RBD_MAX_SNAP_NAME_SIZE 128
  54 #define RBD_MAX_SNAPS 100
  55
  56 typedef struct RBDAIOCB {
  57     BlockDriverAIOCB common;
  58     QEMUBH *bh;
  59     int ret;
  60     QEMUIOVector *qiov;
  61     char *bounce;
  62     int write;
  63     int64_t sector_num;
  64     int error;
  65     struct BDRVRBDState *s;
  66     int cancelled;
  67 } RBDAIOCB;
  68
  69 typedef struct RADOSCB {
  70     int rcbid;
  71     RBDAIOCB *acb;
  72     struct BDRVRBDState *s;
  73     int done;
  74     int64_t size;
  75     char *buf;
  76     int ret;
  77 } RADOSCB;
  78
  79 #define RBD_FD_READ 0
  80 #define RBD_FD_WRITE 1
  81
  82 typedef struct BDRVRBDState {
  83     int fds[2];
  84     rados_t cluster;
  85     rados_ioctx_t io_ctx;
  86     rbd_image_t image;
  87     char name[RBD_MAX_IMAGE_NAME_SIZE];
  88     int qemu_aio_count;
  89     char *snap;
  90     int event_reader_pos;
  91     RADOSCB *event_rcb;
  92 } BDRVRBDState;
  93
  94 static void rbd_aio_bh_cb(void *opaque);
  95
  96 static int qemu_rbd_next_tok(char *dst, int dst_len,
  97                              char *src, char delim,
  98                              const char *name,
  99                              char **p)
 100 {
 101     int l;
 102     char *end;
 103
 104     *p = NULL;
 105
 106     if (delim != '\0') {
 107         for (end = src; *end; ++end) {
 108             if (*end == delim) {
 109                 break;
 110             }
 111             if (*end == '\\' && end[1] != '\0') {
 112                 end++;
 113             }
 114         }
 115         if (*end == delim) {
 116             *p = end + 1;
 117             *end = '\0';
 118         }
 119     }
 120     l = strlen(src);
 121     if (l >= dst_len) {
 122         error_report("%s too long", name);
 123         return -EINVAL;
 124     } else if (l == 0) {
 125         error_report("%s too short", name);
 126         return -EINVAL;
 127     }
 128
 129     pstrcpy(dst, dst_len, src);
 130
 131     return 0;
 132 }
 133
 134 static void qemu_rbd_unescape(char *src)
 135 {
 136     char *p;
 137
 138     for (p = src; *src; ++src, ++p) {
 139         if (*src == '\\' && src[1] != '\0') {
 140             src++;
 141         }
 142         *p = *src;
 143     }
 144     *p = '\0';
 145 }
 146
 147 static int qemu_rbd_parsename(const char *filename,
 148                               char *pool, int pool_len,
 149                               char *snap, int snap_len,
 150                               char *name, int name_len,
 151                               char *conf, int conf_len)
 152 {
 153     const char *start;
 154     char *p, *buf;
 155     int ret;
 156
 157     if (!strstart(filename, "rbd:", &start)) {
 158         return -EINVAL;
 159     }
 160
 161     buf = g_strdup(start);
 162     p = buf;
 163     *snap = '\0';
 164     *conf = '\0';
 165
 166     ret = qemu_rbd_next_tok(pool, pool_len, p, '/', "pool name", &p);
 167     if (ret < 0 || !p) {
 168         ret = -EINVAL;
 169         goto done;
 170     }
 171     qemu_rbd_unescape(pool);
 172
 173     if (strchr(p, '@')) {
 174         ret = qemu_rbd_next_tok(name, name_len, p, '@', "object name", &p);
 175         if (ret < 0) {
 176             goto done;
 177         }
 178         ret = qemu_rbd_next_tok(snap, snap_len, p, ':', "snap name", &p);
 179         qemu_rbd_unescape(snap);
 180     } else {
 181         ret = qemu_rbd_next_tok(name, name_len, p, ':', "object name", &p);
 182     }
 183     qemu_rbd_unescape(name);
 184     if (ret < 0 || !p) {
 185         goto done;
 186     }
 187
 188     ret = qemu_rbd_next_tok(conf, conf_len, p, '\0', "configuration", &p);
 189
 190 done:
 191     g_free(buf);
 192     return ret;
 193 }
 194
 195 static char *qemu_rbd_parse_clientname(const char *conf, char *clientname)
 196 {
 197     const char *p = conf;
 198
 199     while (*p) {
 200         int len;
 201         const char *end = strchr(p, ':');
 202
 203         if (end) {
 204             len = end - p;
 205         } else {
 206             len = strlen(p);
 207         }
 208
 209         if (strncmp(p, "id=", 3) == 0) {
 210             len -= 3;
 211             strncpy(clientname, p + 3, len);
 212             clientname[len] = '\0';
 213             return clientname;
 214         }
 215         if (end == NULL) {
 216             break;
 217         }
 218         p = end + 1;
 219     }
 220     return NULL;
 221 }
 222
 223 static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
 224 {
 225     char *p, *buf;
 226     char name[RBD_MAX_CONF_NAME_SIZE];
 227     char value[RBD_MAX_CONF_VAL_SIZE];
 228     int ret = 0;
 229
 230     buf = g_strdup(conf);
 231     p = buf;
 232
 233     while (p) {
 234         ret = qemu_rbd_next_tok(name, sizeof(name), p,
 235                                 '=', "conf option name", &p);
 236         if (ret < 0) {
 237             break;
 238         }
 239         qemu_rbd_unescape(name);
 240
 241         if (!p) {
 242             error_report("conf option %s has no value", name);
 243             ret = -EINVAL;
 244             break;
 245         }
 246
 247         ret = qemu_rbd_next_tok(value, sizeof(value), p,
 248                                 ':', "conf option value", &p);
 249         if (ret < 0) {
 250             break;
 251         }
 252         qemu_rbd_unescape(value);
 253
 254         if (strcmp(name, "conf") == 0) {
 255             ret = rados_conf_read_file(cluster, value);
 256             if (ret < 0) {
 257                 error_report("error reading conf file %s", value);
 258                 break;
 259             }
 260         } else if (strcmp(name, "id") == 0) {
 261             /* ignore, this is parsed by qemu_rbd_parse_clientname() */
 262         } else {
 263             ret = rados_conf_set(cluster, name, value);
 264             if (ret < 0) {
 265                 error_report("invalid conf option %s", name);
 266                 ret = -EINVAL;
 267                 break;
 268             }
 269         }
 270     }
 271
 272     g_free(buf);
 273     return ret;
 274 }
 275
 276 static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options)
 277 {
 278     int64_t bytes = 0;
 279     int64_t objsize;
 280     int obj_order = 0;
 281     char pool[RBD_MAX_POOL_NAME_SIZE];
 282     char name[RBD_MAX_IMAGE_NAME_SIZE];
 283     char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
 284     char conf[RBD_MAX_CONF_SIZE];
 285     char clientname_buf[RBD_MAX_CONF_SIZE];
 286     char *clientname;
 287     rados_t cluster;
 288     rados_ioctx_t io_ctx;
 289     int ret;
 290
 291     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
 292                            snap_buf, sizeof(snap_buf),
 293                            name, sizeof(name),
 294                            conf, sizeof(conf)) < 0) {
 295         return -EINVAL;
 296     }
 297
 298     /* Read out options */
 299     while (options && options->name) {
 300         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
 301             bytes = options->value.n;
 302         } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
 303             if (options->value.n) {
 304                 objsize = options->value.n;
 305                 if ((objsize - 1) & objsize) {    /* not a power of 2? */
 306                     error_report("obj size needs to be power of 2");
 307                     return -EINVAL;
 308                 }
 309                 if (objsize < 4096) {
 310                     error_report("obj size too small");
 311                     return -EINVAL;
 312                 }
 313                 obj_order = ffs(objsize) - 1;
 314             }
 315         }
 316         options++;
 317     }
 318
 319     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
 320     if (rados_create(&cluster, clientname) < 0) {
 321         error_report("error initializing");
 322         return -EIO;
 323     }
 324
 325     if (strstr(conf, "conf=") == NULL) {
 326         /* try default location, but ignore failure */
 327         rados_conf_read_file(cluster, NULL);
 328     }
 329
 330     if (conf[0] != '\0' &&
 331         qemu_rbd_set_conf(cluster, conf) < 0) {
 332         error_report("error setting config options");
 333         rados_shutdown(cluster);
 334         return -EIO;
 335     }
 336
 337     if (rados_connect(cluster) < 0) {
 338         error_report("error connecting");
 339         rados_shutdown(cluster);
 340         return -EIO;
 341     }
 342
 343     if (rados_ioctx_create(cluster, pool, &io_ctx) < 0) {
 344         error_report("error opening pool %s", pool);
 345         rados_shutdown(cluster);
 346         return -EIO;
 347     }
 348
 349     ret = rbd_create(io_ctx, name, bytes, &obj_order);
 350     rados_ioctx_destroy(io_ctx);
 351     rados_shutdown(cluster);
 352
 353     return ret;
 354 }
 355
 356 /*
 357  * This aio completion is being called from qemu_rbd_aio_event_reader()
 358  * and runs in qemu context. It schedules a bh, but just in case the aio
 359  * was not cancelled before.
 360  */
 361 static void qemu_rbd_complete_aio(RADOSCB *rcb)
 362 {
 363     RBDAIOCB *acb = rcb->acb;
 364     int64_t r;
 365
 366     if (acb->cancelled) {
 367         qemu_vfree(acb->bounce);
 368         qemu_aio_release(acb);
 369         goto done;
 370     }
 371
 372     r = rcb->ret;
 373
 374     if (acb->write) {
 375         if (r < 0) {
 376             acb->ret = r;
 377             acb->error = 1;
 378         } else if (!acb->error) {
 379             acb->ret = rcb->size;
 380         }
 381     } else {
 382         if (r < 0) {
 383             memset(rcb->buf, 0, rcb->size);
 384             acb->ret = r;
 385             acb->error = 1;
 386         } else if (r < rcb->size) {
 387             memset(rcb->buf + r, 0, rcb->size - r);
 388             if (!acb->error) {
 389                 acb->ret = rcb->size;
 390             }
 391         } else if (!acb->error) {
 392             acb->ret = r;
 393         }
 394     }
 395     /* Note that acb->bh can be NULL in case where the aio was cancelled */
 396     acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb);
 397     qemu_bh_schedule(acb->bh);
 398 done:
 399     g_free(rcb);
 400 }
 401
 402 /*
 403  * aio fd read handler. It runs in the qemu context and calls the
 404  * completion handling of completed rados aio operations.
 405  */
 406 static void qemu_rbd_aio_event_reader(void *opaque)
 407 {
 408     BDRVRBDState *s = opaque;
 409
 410     ssize_t ret;
 411
 412     do {
 413         char *p = (char *)&s->event_rcb;
 414
 415         /* now read the rcb pointer that was sent from a non qemu thread */
 416         ret = read(s->fds[RBD_FD_READ], p + s->event_reader_pos,
 417                    sizeof(s->event_rcb) - s->event_reader_pos);
 418         if (ret > 0) {
 419             s->event_reader_pos += ret;
 420             if (s->event_reader_pos == sizeof(s->event_rcb)) {
 421                 s->event_reader_pos = 0;
 422                 qemu_rbd_complete_aio(s->event_rcb);
 423                 s->qemu_aio_count--;
 424             }
 425         }
 426     } while (ret < 0 && errno == EINTR);
 427 }
 428
 429 static int qemu_rbd_aio_flush_cb(void *opaque)
 430 {
 431     BDRVRBDState *s = opaque;
 432
 433     return (s->qemu_aio_count > 0);
 434 }
 435
 436 static int qemu_rbd_open(BlockDriverState *bs, const char *filename, int flags)
 437 {
 438     BDRVRBDState *s = bs->opaque;
 439     char pool[RBD_MAX_POOL_NAME_SIZE];
 440     char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
 441     char conf[RBD_MAX_CONF_SIZE];
 442     char clientname_buf[RBD_MAX_CONF_SIZE];
 443     char *clientname;
 444     int r;
 445
 446     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
 447                            snap_buf, sizeof(snap_buf),
 448                            s->name, sizeof(s->name),
 449                            conf, sizeof(conf)) < 0) {
 450         return -EINVAL;
 451     }
 452
 453     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
 454     r = rados_create(&s->cluster, clientname);
 455     if (r < 0) {
 456         error_report("error initializing");
 457         return r;
 458     }
 459
 460     s->snap = NULL;
 461     if (snap_buf[0] != '\0') {
 462         s->snap = g_strdup(snap_buf);
 463     }
 464
 465     if (strstr(conf, "conf=") == NULL) {
 466         /* try default location, but ignore failure */
 467         rados_conf_read_file(s->cluster, NULL);
 468     }
 469
 470     if (conf[0] != '\0') {
 471         r = qemu_rbd_set_conf(s->cluster, conf);
 472         if (r < 0) {
 473             error_report("error setting config options");
 474             goto failed_shutdown;
 475         }
 476     }
 477
 478     r = rados_connect(s->cluster);
 479     if (r < 0) {
 480         error_report("error connecting");
 481         goto failed_shutdown;
 482     }
 483
 484     r = rados_ioctx_create(s->cluster, pool, &s->io_ctx);
 485     if (r < 0) {
 486         error_report("error opening pool %s", pool);
 487         goto failed_shutdown;
 488     }
 489
 490     r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
 491     if (r < 0) {
 492         error_report("error reading header from %s", s->name);
 493         goto failed_open;
 494     }
 495
 496     bs->read_only = (s->snap != NULL);
 497
 498     s->event_reader_pos = 0;
 499     r = qemu_pipe(s->fds);
 500     if (r < 0) {
 501         error_report("error opening eventfd");
 502         goto failed;
 503     }
 504     fcntl(s->fds[0], F_SETFL, O_NONBLOCK);
 505     fcntl(s->fds[1], F_SETFL, O_NONBLOCK);
 506     qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], qemu_rbd_aio_event_reader,
 507                             NULL, qemu_rbd_aio_flush_cb, NULL, s);
 508
 509
 510     return 0;
 511
 512 failed:
 513     rbd_close(s->image);
 514 failed_open:
 515     rados_ioctx_destroy(s->io_ctx);
 516 failed_shutdown:
 517     rados_shutdown(s->cluster);
 518     g_free(s->snap);
 519     return r;
 520 }
 521
 522 static void qemu_rbd_close(BlockDriverState *bs)
 523 {
 524     BDRVRBDState *s = bs->opaque;
 525
 526     close(s->fds[0]);
 527     close(s->fds[1]);
 528     qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], NULL , NULL, NULL, NULL,
 529         NULL);
 530
 531     rbd_close(s->image);
 532     rados_ioctx_destroy(s->io_ctx);
 533     g_free(s->snap);
 534     rados_shutdown(s->cluster);
 535 }
 536
 537 /*
 538  * Cancel aio. Since we don't reference acb in a non qemu threads,
 539  * it is safe to access it here.
 540  */
 541 static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb)
 542 {
 543     RBDAIOCB *acb = (RBDAIOCB *) blockacb;
 544     acb->cancelled = 1;
 545 }
 546
 547 static AIOPool rbd_aio_pool = {
 548     .aiocb_size = sizeof(RBDAIOCB),
 549     .cancel = qemu_rbd_aio_cancel,
 550 };
 551
 552 static int qemu_rbd_send_pipe(BDRVRBDState *s, RADOSCB *rcb)
 553 {
 554     int ret = 0;
 555     while (1) {
 556         fd_set wfd;
 557         int fd = s->fds[RBD_FD_WRITE];
 558
 559         /* send the op pointer to the qemu thread that is responsible
 560            for the aio/op completion. Must do it in a qemu thread context */
 561         ret = write(fd, (void *)&rcb, sizeof(rcb));
 562         if (ret >= 0) {
 563             break;
 564         }
 565         if (errno == EINTR) {
 566             continue;
 567         }
 568         if (errno != EAGAIN) {
 569             break;
 570         }
 571
 572         FD_ZERO(&wfd);
 573         FD_SET(fd, &wfd);
 574         do {
 575             ret = select(fd + 1, NULL, &wfd, NULL, NULL);
 576         } while (ret < 0 && errno == EINTR);
 577     }
 578
 579     return ret;
 580 }
 581
 582 /*
 583  * This is the callback function for rbd_aio_read and _write
 584  *
 585  * Note: this function is being called from a non qemu thread so
 586  * we need to be careful about what we do here. Generally we only
 587  * write to the block notification pipe, and do the rest of the
 588  * io completion handling from qemu_rbd_aio_event_reader() which
 589  * runs in a qemu context.
 590  */
 591 static void rbd_finish_aiocb(rbd_completion_t c, RADOSCB *rcb)
 592 {
 593     int ret;
 594     rcb->ret = rbd_aio_get_return_value(c);
 595     rbd_aio_release(c);
 596     ret = qemu_rbd_send_pipe(rcb->s, rcb);
 597     if (ret < 0) {
 598         error_report("failed writing to acb->s->fds");
 599         g_free(rcb);
 600     }
 601 }
 602
 603 /* Callback when all queued rbd_aio requests are complete */
 604
 605 static void rbd_aio_bh_cb(void *opaque)
 606 {
 607     RBDAIOCB *acb = opaque;
 608
 609     if (!acb->write) {
 610         qemu_iovec_from_buffer(acb->qiov, acb->bounce, acb->qiov->size);
 611     }
 612     qemu_vfree(acb->bounce);
 613     acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
 614     qemu_bh_delete(acb->bh);
 615     acb->bh = NULL;
 616
 617     qemu_aio_release(acb);
 618 }
 619
 620 static BlockDriverAIOCB *rbd_aio_rw_vector(BlockDriverState *bs,
 621                                            int64_t sector_num,
 622                                            QEMUIOVector *qiov,
 623                                            int nb_sectors,
 624                                            BlockDriverCompletionFunc *cb,
 625                                            void *opaque, int write)
 626 {
 627     RBDAIOCB *acb;
 628     RADOSCB *rcb;
 629     rbd_completion_t c;
 630     int64_t off, size;
 631     char *buf;
 632     int r;
 633
 634     BDRVRBDState *s = bs->opaque;
 635
 636     acb = qemu_aio_get(&rbd_aio_pool, bs, cb, opaque);
 637     acb->write = write;
 638     acb->qiov = qiov;
 639     acb->bounce = qemu_blockalign(bs, qiov->size);
 640     acb->ret = 0;
 641     acb->error = 0;
 642     acb->s = s;
 643     acb->cancelled = 0;
 644     acb->bh = NULL;
 645
 646     if (write) {
 647         qemu_iovec_to_buffer(acb->qiov, acb->bounce);
 648     }
 649
 650     buf = acb->bounce;
 651
 652     off = sector_num * BDRV_SECTOR_SIZE;
 653     size = nb_sectors * BDRV_SECTOR_SIZE;
 654
 655     s->qemu_aio_count++; /* All the RADOSCB */
 656
 657     rcb = g_malloc(sizeof(RADOSCB));
 658     rcb->done = 0;
 659     rcb->acb = acb;
 660     rcb->buf = buf;
 661     rcb->s = acb->s;
 662     rcb->size = size;
 663     r = rbd_aio_create_completion(rcb, (rbd_callback_t) rbd_finish_aiocb, &c);
 664     if (r < 0) {
 665         goto failed;
 666     }
 667
 668     if (write) {
 669         r = rbd_aio_write(s->image, off, size, buf, c);
 670     } else {
 671         r = rbd_aio_read(s->image, off, size, buf, c);
 672     }
 673
 674     if (r < 0) {
 675         goto failed;
 676     }
 677
 678     return &acb->common;
 679
 680 failed:
 681     g_free(rcb);
 682     s->qemu_aio_count--;
 683     qemu_aio_release(acb);
 684     return NULL;
 685 }
 686
 687 static BlockDriverAIOCB *qemu_rbd_aio_readv(BlockDriverState *bs,
 688                                             int64_t sector_num,
 689                                             QEMUIOVector *qiov,
 690                                             int nb_sectors,
 691                                             BlockDriverCompletionFunc *cb,
 692                                             void *opaque)
 693 {
 694     return rbd_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
 695 }
 696
 697 static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
 698                                              int64_t sector_num,
 699                                              QEMUIOVector *qiov,
 700                                              int nb_sectors,
 701                                              BlockDriverCompletionFunc *cb,
 702                                              void *opaque)
 703 {
 704     return rbd_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
 705 }
 706
 707 static int qemu_rbd_co_flush(BlockDriverState *bs)
 708 {
 709 #if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 1)
 710     /* rbd_flush added in 0.1.1 */
 711     BDRVRBDState *s = bs->opaque;
 712     return rbd_flush(s->image);
 713 #else
 714     return 0;
 715 #endif
 716 }
 717
 718 static int qemu_rbd_getinfo(BlockDriverState *bs, BlockDriverInfo *bdi)
 719 {
 720     BDRVRBDState *s = bs->opaque;
 721     rbd_image_info_t info;
 722     int r;
 723
 724     r = rbd_stat(s->image, &info, sizeof(info));
 725     if (r < 0) {
 726         return r;
 727     }
 728
 729     bdi->cluster_size = info.obj_size;
 730     return 0;
 731 }
 732
 733 static int64_t qemu_rbd_getlength(BlockDriverState *bs)
 734 {
 735     BDRVRBDState *s = bs->opaque;
 736     rbd_image_info_t info;
 737     int r;
 738
 739     r = rbd_stat(s->image, &info, sizeof(info));
 740     if (r < 0) {
 741         return r;
 742     }
 743
 744     return info.size;
 745 }
 746
 747 static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
 748 {
 749     BDRVRBDState *s = bs->opaque;
 750     int r;
 751
 752     r = rbd_resize(s->image, offset);
 753     if (r < 0) {
 754         return r;
 755     }
 756
 757     return 0;
 758 }
 759
 760 static int qemu_rbd_snap_create(BlockDriverState *bs,
 761                                 QEMUSnapshotInfo *sn_info)
 762 {
 763     BDRVRBDState *s = bs->opaque;
 764     int r;
 765
 766     if (sn_info->name[0] == '\0') {
 767         return -EINVAL; /* we need a name for rbd snapshots */
 768     }
 769
 770     /*
 771      * rbd snapshots are using the name as the user controlled unique identifier
 772      * we can't use the rbd snapid for that purpose, as it can't be set
 773      */
 774     if (sn_info->id_str[0] != '\0' &&
 775         strcmp(sn_info->id_str, sn_info->name) != 0) {
 776         return -EINVAL;
 777     }
 778
 779     if (strlen(sn_info->name) >= sizeof(sn_info->id_str)) {
 780         return -ERANGE;
 781     }
 782
 783     r = rbd_snap_create(s->image, sn_info->name);
 784     if (r < 0) {
 785         error_report("failed to create snap: %s", strerror(-r));
 786         return r;
 787     }
 788
 789     return 0;
 790 }
 791
 792 static int qemu_rbd_snap_remove(BlockDriverState *bs,
 793                                 const char *snapshot_name)
 794 {
 795     BDRVRBDState *s = bs->opaque;
 796     int r;
 797
 798     r = rbd_snap_remove(s->image, snapshot_name);
 799     return r;
 800 }
 801
 802 static int qemu_rbd_snap_rollback(BlockDriverState *bs,
 803                                   const char *snapshot_name)
 804 {
 805     BDRVRBDState *s = bs->opaque;
 806     int r;
 807
 808     r = rbd_snap_rollback(s->image, snapshot_name);
 809     return r;
 810 }
 811
 812 static int qemu_rbd_snap_list(BlockDriverState *bs,
 813                               QEMUSnapshotInfo **psn_tab)
 814 {
 815     BDRVRBDState *s = bs->opaque;
 816     QEMUSnapshotInfo *sn_info, *sn_tab = NULL;
 817     int i, snap_count;
 818     rbd_snap_info_t *snaps;
 819     int max_snaps = RBD_MAX_SNAPS;
 820
 821     do {
 822         snaps = g_malloc(sizeof(*snaps) * max_snaps);
 823         snap_count = rbd_snap_list(s->image, snaps, &max_snaps);
 824         if (snap_count < 0) {
 825             g_free(snaps);
 826         }
 827     } while (snap_count == -ERANGE);
 828
 829     if (snap_count <= 0) {
 830         goto done;
 831     }
 832
 833     sn_tab = g_malloc0(snap_count * sizeof(QEMUSnapshotInfo));
 834
 835     for (i = 0; i < snap_count; i++) {
 836         const char *snap_name = snaps[i].name;
 837
 838         sn_info = sn_tab + i;
 839         pstrcpy(sn_info->id_str, sizeof(sn_info->id_str), snap_name);
 840         pstrcpy(sn_info->name, sizeof(sn_info->name), snap_name);
 841
 842         sn_info->vm_state_size = snaps[i].size;
 843         sn_info->date_sec = 0;
 844         sn_info->date_nsec = 0;
 845         sn_info->vm_clock_nsec = 0;
 846     }
 847     rbd_snap_list_end(snaps);
 848
 849  done:
 850     *psn_tab = sn_tab;
 851     return snap_count;
 852 }
 853
 854 static QEMUOptionParameter qemu_rbd_create_options[] = {
 855     {
 856      .name = BLOCK_OPT_SIZE,
 857      .type = OPT_SIZE,
 858      .help = "Virtual disk size"
 859     },
 860     {
 861      .name = BLOCK_OPT_CLUSTER_SIZE,
 862      .type = OPT_SIZE,
 863      .help = "RBD object size"
 864     },
 865     {NULL}
 866 };
 867
 868 static BlockDriver bdrv_rbd = {
 869     .format_name        = "rbd",
 870     .instance_size      = sizeof(BDRVRBDState),
 871     .bdrv_file_open     = qemu_rbd_open,
 872     .bdrv_close         = qemu_rbd_close,
 873     .bdrv_create        = qemu_rbd_create,
 874     .bdrv_get_info      = qemu_rbd_getinfo,
 875     .create_options     = qemu_rbd_create_options,
 876     .bdrv_getlength     = qemu_rbd_getlength,
 877     .bdrv_truncate      = qemu_rbd_truncate,
 878     .protocol_name      = "rbd",
 879
 880     .bdrv_aio_readv         = qemu_rbd_aio_readv,
 881     .bdrv_aio_writev        = qemu_rbd_aio_writev,
 882     .bdrv_co_flush_to_disk  = qemu_rbd_co_flush,
 883
 884     .bdrv_snapshot_create   = qemu_rbd_snap_create,
 885     .bdrv_snapshot_delete   = qemu_rbd_snap_remove,
 886     .bdrv_snapshot_list     = qemu_rbd_snap_list,
 887     .bdrv_snapshot_goto     = qemu_rbd_snap_rollback,
 888 };
 889
 890 static void bdrv_rbd_init(void)
 891 {
 892     bdrv_register(&bdrv_rbd);
 893 }
 894
 895 block_init(bdrv_rbd_init);