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-report.h"
  18 #include "block/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 /* rbd_aio_discard added in 0.1.2 */
  48 #if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 2)
  49 #define LIBRBD_SUPPORTS_DISCARD
  50 #else
  51 #undef LIBRBD_SUPPORTS_DISCARD
  52 #endif
  53
  54 #define OBJ_MAX_SIZE (1UL << OBJ_DEFAULT_OBJ_ORDER)
  55
  56 #define RBD_MAX_CONF_NAME_SIZE 128
  57 #define RBD_MAX_CONF_VAL_SIZE 512
  58 #define RBD_MAX_CONF_SIZE 1024
  59 #define RBD_MAX_POOL_NAME_SIZE 128
  60 #define RBD_MAX_SNAP_NAME_SIZE 128
  61 #define RBD_MAX_SNAPS 100
  62
  63 typedef enum {
  64     RBD_AIO_READ,
  65     RBD_AIO_WRITE,
  66     RBD_AIO_DISCARD,
  67     RBD_AIO_FLUSH
  68 } RBDAIOCmd;
  69
  70 typedef struct RBDAIOCB {
  71     BlockDriverAIOCB common;
  72     QEMUBH *bh;
  73     int64_t ret;
  74     QEMUIOVector *qiov;
  75     char *bounce;
  76     RBDAIOCmd cmd;
  77     int64_t sector_num;
  78     int error;
  79     struct BDRVRBDState *s;
  80     int cancelled;
  81     int status;
  82 } RBDAIOCB;
  83
  84 typedef struct RADOSCB {
  85     int rcbid;
  86     RBDAIOCB *acb;
  87     struct BDRVRBDState *s;
  88     int done;
  89     int64_t size;
  90     char *buf;
  91     int64_t ret;
  92 } RADOSCB;
  93
  94 #define RBD_FD_READ 0
  95 #define RBD_FD_WRITE 1
  96
  97 typedef struct BDRVRBDState {
  98     int fds[2];
  99     rados_t cluster;
 100     rados_ioctx_t io_ctx;
 101     rbd_image_t image;
 102     char name[RBD_MAX_IMAGE_NAME_SIZE];
 103     int qemu_aio_count;
 104     char *snap;
 105     int event_reader_pos;
 106     RADOSCB *event_rcb;
 107 } BDRVRBDState;
 108
 109 static void rbd_aio_bh_cb(void *opaque);
 110
 111 static int qemu_rbd_next_tok(char *dst, int dst_len,
 112                              char *src, char delim,
 113                              const char *name,
 114                              char **p)
 115 {
 116     int l;
 117     char *end;
 118
 119     *p = NULL;
 120
 121     if (delim != '\0') {
 122         for (end = src; *end; ++end) {
 123             if (*end == delim) {
 124                 break;
 125             }
 126             if (*end == '\\' && end[1] != '\0') {
 127                 end++;
 128             }
 129         }
 130         if (*end == delim) {
 131             *p = end + 1;
 132             *end = '\0';
 133         }
 134     }
 135     l = strlen(src);
 136     if (l >= dst_len) {
 137         error_report("%s too long", name);
 138         return -EINVAL;
 139     } else if (l == 0) {
 140         error_report("%s too short", name);
 141         return -EINVAL;
 142     }
 143
 144     pstrcpy(dst, dst_len, src);
 145
 146     return 0;
 147 }
 148
 149 static void qemu_rbd_unescape(char *src)
 150 {
 151     char *p;
 152
 153     for (p = src; *src; ++src, ++p) {
 154         if (*src == '\\' && src[1] != '\0') {
 155             src++;
 156         }
 157         *p = *src;
 158     }
 159     *p = '\0';
 160 }
 161
 162 static int qemu_rbd_parsename(const char *filename,
 163                               char *pool, int pool_len,
 164                               char *snap, int snap_len,
 165                               char *name, int name_len,
 166                               char *conf, int conf_len)
 167 {
 168     const char *start;
 169     char *p, *buf;
 170     int ret;
 171
 172     if (!strstart(filename, "rbd:", &start)) {
 173         return -EINVAL;
 174     }
 175
 176     buf = g_strdup(start);
 177     p = buf;
 178     *snap = '\0';
 179     *conf = '\0';
 180
 181     ret = qemu_rbd_next_tok(pool, pool_len, p, '/', "pool name", &p);
 182     if (ret < 0 || !p) {
 183         ret = -EINVAL;
 184         goto done;
 185     }
 186     qemu_rbd_unescape(pool);
 187
 188     if (strchr(p, '@')) {
 189         ret = qemu_rbd_next_tok(name, name_len, p, '@', "object name", &p);
 190         if (ret < 0) {
 191             goto done;
 192         }
 193         ret = qemu_rbd_next_tok(snap, snap_len, p, ':', "snap name", &p);
 194         qemu_rbd_unescape(snap);
 195     } else {
 196         ret = qemu_rbd_next_tok(name, name_len, p, ':', "object name", &p);
 197     }
 198     qemu_rbd_unescape(name);
 199     if (ret < 0 || !p) {
 200         goto done;
 201     }
 202
 203     ret = qemu_rbd_next_tok(conf, conf_len, p, '\0', "configuration", &p);
 204
 205 done:
 206     g_free(buf);
 207     return ret;
 208 }
 209
 210 static char *qemu_rbd_parse_clientname(const char *conf, char *clientname)
 211 {
 212     const char *p = conf;
 213
 214     while (*p) {
 215         int len;
 216         const char *end = strchr(p, ':');
 217
 218         if (end) {
 219             len = end - p;
 220         } else {
 221             len = strlen(p);
 222         }
 223
 224         if (strncmp(p, "id=", 3) == 0) {
 225             len -= 3;
 226             strncpy(clientname, p + 3, len);
 227             clientname[len] = '\0';
 228             return clientname;
 229         }
 230         if (end == NULL) {
 231             break;
 232         }
 233         p = end + 1;
 234     }
 235     return NULL;
 236 }
 237
 238 static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
 239 {
 240     char *p, *buf;
 241     char name[RBD_MAX_CONF_NAME_SIZE];
 242     char value[RBD_MAX_CONF_VAL_SIZE];
 243     int ret = 0;
 244
 245     buf = g_strdup(conf);
 246     p = buf;
 247
 248     while (p) {
 249         ret = qemu_rbd_next_tok(name, sizeof(name), p,
 250                                 '=', "conf option name", &p);
 251         if (ret < 0) {
 252             break;
 253         }
 254         qemu_rbd_unescape(name);
 255
 256         if (!p) {
 257             error_report("conf option %s has no value", name);
 258             ret = -EINVAL;
 259             break;
 260         }
 261
 262         ret = qemu_rbd_next_tok(value, sizeof(value), p,
 263                                 ':', "conf option value", &p);
 264         if (ret < 0) {
 265             break;
 266         }
 267         qemu_rbd_unescape(value);
 268
 269         if (strcmp(name, "conf") == 0) {
 270             ret = rados_conf_read_file(cluster, value);
 271             if (ret < 0) {
 272                 error_report("error reading conf file %s", value);
 273                 break;
 274             }
 275         } else if (strcmp(name, "id") == 0) {
 276             /* ignore, this is parsed by qemu_rbd_parse_clientname() */
 277         } else {
 278             ret = rados_conf_set(cluster, name, value);
 279             if (ret < 0) {
 280                 error_report("invalid conf option %s", name);
 281                 ret = -EINVAL;
 282                 break;
 283             }
 284         }
 285     }
 286
 287     g_free(buf);
 288     return ret;
 289 }
 290
 291 static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options)
 292 {
 293     int64_t bytes = 0;
 294     int64_t objsize;
 295     int obj_order = 0;
 296     char pool[RBD_MAX_POOL_NAME_SIZE];
 297     char name[RBD_MAX_IMAGE_NAME_SIZE];
 298     char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
 299     char conf[RBD_MAX_CONF_SIZE];
 300     char clientname_buf[RBD_MAX_CONF_SIZE];
 301     char *clientname;
 302     rados_t cluster;
 303     rados_ioctx_t io_ctx;
 304     int ret;
 305
 306     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
 307                            snap_buf, sizeof(snap_buf),
 308                            name, sizeof(name),
 309                            conf, sizeof(conf)) < 0) {
 310         return -EINVAL;
 311     }
 312
 313     /* Read out options */
 314     while (options && options->name) {
 315         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
 316             bytes = options->value.n;
 317         } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
 318             if (options->value.n) {
 319                 objsize = options->value.n;
 320                 if ((objsize - 1) & objsize) {    /* not a power of 2? */
 321                     error_report("obj size needs to be power of 2");
 322                     return -EINVAL;
 323                 }
 324                 if (objsize < 4096) {
 325                     error_report("obj size too small");
 326                     return -EINVAL;
 327                 }
 328                 obj_order = ffs(objsize) - 1;
 329             }
 330         }
 331         options++;
 332     }
 333
 334     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
 335     if (rados_create(&cluster, clientname) < 0) {
 336         error_report("error initializing");
 337         return -EIO;
 338     }
 339
 340     if (strstr(conf, "conf=") == NULL) {
 341         /* try default location, but ignore failure */
 342         rados_conf_read_file(cluster, NULL);
 343     }
 344
 345     if (conf[0] != '\0' &&
 346         qemu_rbd_set_conf(cluster, conf) < 0) {
 347         error_report("error setting config options");
 348         rados_shutdown(cluster);
 349         return -EIO;
 350     }
 351
 352     if (rados_connect(cluster) < 0) {
 353         error_report("error connecting");
 354         rados_shutdown(cluster);
 355         return -EIO;
 356     }
 357
 358     if (rados_ioctx_create(cluster, pool, &io_ctx) < 0) {
 359         error_report("error opening pool %s", pool);
 360         rados_shutdown(cluster);
 361         return -EIO;
 362     }
 363
 364     ret = rbd_create(io_ctx, name, bytes, &obj_order);
 365     rados_ioctx_destroy(io_ctx);
 366     rados_shutdown(cluster);
 367
 368     return ret;
 369 }
 370
 371 /*
 372  * This aio completion is being called from qemu_rbd_aio_event_reader()
 373  * and runs in qemu context. It schedules a bh, but just in case the aio
 374  * was not cancelled before.
 375  */
 376 static void qemu_rbd_complete_aio(RADOSCB *rcb)
 377 {
 378     RBDAIOCB *acb = rcb->acb;
 379     int64_t r;
 380
 381     r = rcb->ret;
 382
 383     if (acb->cmd != RBD_AIO_READ) {
 384         if (r < 0) {
 385             acb->ret = r;
 386             acb->error = 1;
 387         } else if (!acb->error) {
 388             acb->ret = rcb->size;
 389         }
 390     } else {
 391         if (r < 0) {
 392             memset(rcb->buf, 0, rcb->size);
 393             acb->ret = r;
 394             acb->error = 1;
 395         } else if (r < rcb->size) {
 396             memset(rcb->buf + r, 0, rcb->size - r);
 397             if (!acb->error) {
 398                 acb->ret = rcb->size;
 399             }
 400         } else if (!acb->error) {
 401             acb->ret = r;
 402         }
 403     }
 404     /* Note that acb->bh can be NULL in case where the aio was cancelled */
 405     acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb);
 406     qemu_bh_schedule(acb->bh);
 407     g_free(rcb);
 408 }
 409
 410 /*
 411  * aio fd read handler. It runs in the qemu context and calls the
 412  * completion handling of completed rados aio operations.
 413  */
 414 static void qemu_rbd_aio_event_reader(void *opaque)
 415 {
 416     BDRVRBDState *s = opaque;
 417
 418     ssize_t ret;
 419
 420     do {
 421         char *p = (char *)&s->event_rcb;
 422
 423         /* now read the rcb pointer that was sent from a non qemu thread */
 424         ret = read(s->fds[RBD_FD_READ], p + s->event_reader_pos,
 425                    sizeof(s->event_rcb) - s->event_reader_pos);
 426         if (ret > 0) {
 427             s->event_reader_pos += ret;
 428             if (s->event_reader_pos == sizeof(s->event_rcb)) {
 429                 s->event_reader_pos = 0;
 430                 qemu_rbd_complete_aio(s->event_rcb);
 431                 s->qemu_aio_count--;
 432             }
 433         }
 434     } while (ret < 0 && errno == EINTR);
 435 }
 436
 437 static int qemu_rbd_aio_flush_cb(void *opaque)
 438 {
 439     BDRVRBDState *s = opaque;
 440
 441     return (s->qemu_aio_count > 0);
 442 }
 443
 444 /* TODO Convert to fine grained options */
 445 static QemuOptsList runtime_opts = {
 446     .name = "rbd",
 447     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 448     .desc = {
 449         {
 450             .name = "filename",
 451             .type = QEMU_OPT_STRING,
 452             .help = "Specification of the rbd image",
 453         },
 454         { /* end of list */ }
 455     },
 456 };
 457
 458 static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags)
 459 {
 460     BDRVRBDState *s = bs->opaque;
 461     char pool[RBD_MAX_POOL_NAME_SIZE];
 462     char snap_buf[RBD_MAX_SNAP_NAME_SIZE];
 463     char conf[RBD_MAX_CONF_SIZE];
 464     char clientname_buf[RBD_MAX_CONF_SIZE];
 465     char *clientname;
 466     QemuOpts *opts;
 467     Error *local_err = NULL;
 468     const char *filename;
 469     int r;
 470
 471     opts = qemu_opts_create_nofail(&runtime_opts);
 472     qemu_opts_absorb_qdict(opts, options, &local_err);
 473     if (error_is_set(&local_err)) {
 474         qerror_report_err(local_err);
 475         error_free(local_err);
 476         qemu_opts_del(opts);
 477         return -EINVAL;
 478     }
 479
 480     filename = qemu_opt_get(opts, "filename");
 481     qemu_opts_del(opts);
 482
 483     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
 484                            snap_buf, sizeof(snap_buf),
 485                            s->name, sizeof(s->name),
 486                            conf, sizeof(conf)) < 0) {
 487         return -EINVAL;
 488     }
 489
 490     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
 491     r = rados_create(&s->cluster, clientname);
 492     if (r < 0) {
 493         error_report("error initializing");
 494         return r;
 495     }
 496
 497     s->snap = NULL;
 498     if (snap_buf[0] != '\0') {
 499         s->snap = g_strdup(snap_buf);
 500     }
 501
 502     /*
 503      * Fallback to more conservative semantics if setting cache
 504      * options fails. Ignore errors from setting rbd_cache because the
 505      * only possible error is that the option does not exist, and
 506      * librbd defaults to no caching. If write through caching cannot
 507      * be set up, fall back to no caching.
 508      */
 509     if (flags & BDRV_O_NOCACHE) {
 510         rados_conf_set(s->cluster, "rbd_cache", "false");
 511     } else {
 512         rados_conf_set(s->cluster, "rbd_cache", "true");
 513     }
 514
 515     if (strstr(conf, "conf=") == NULL) {
 516         /* try default location, but ignore failure */
 517         rados_conf_read_file(s->cluster, NULL);
 518     }
 519
 520     if (conf[0] != '\0') {
 521         r = qemu_rbd_set_conf(s->cluster, conf);
 522         if (r < 0) {
 523             error_report("error setting config options");
 524             goto failed_shutdown;
 525         }
 526     }
 527
 528     r = rados_connect(s->cluster);
 529     if (r < 0) {
 530         error_report("error connecting");
 531         goto failed_shutdown;
 532     }
 533
 534     r = rados_ioctx_create(s->cluster, pool, &s->io_ctx);
 535     if (r < 0) {
 536         error_report("error opening pool %s", pool);
 537         goto failed_shutdown;
 538     }
 539
 540     r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
 541     if (r < 0) {
 542         error_report("error reading header from %s", s->name);
 543         goto failed_open;
 544     }
 545
 546     bs->read_only = (s->snap != NULL);
 547
 548     s->event_reader_pos = 0;
 549     r = qemu_pipe(s->fds);
 550     if (r < 0) {
 551         error_report("error opening eventfd");
 552         goto failed;
 553     }
 554     fcntl(s->fds[0], F_SETFL, O_NONBLOCK);
 555     fcntl(s->fds[1], F_SETFL, O_NONBLOCK);
 556     qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], qemu_rbd_aio_event_reader,
 557                             NULL, qemu_rbd_aio_flush_cb, s);
 558
 559
 560     return 0;
 561
 562 failed:
 563     rbd_close(s->image);
 564 failed_open:
 565     rados_ioctx_destroy(s->io_ctx);
 566 failed_shutdown:
 567     rados_shutdown(s->cluster);
 568     g_free(s->snap);
 569     return r;
 570 }
 571
 572 static void qemu_rbd_close(BlockDriverState *bs)
 573 {
 574     BDRVRBDState *s = bs->opaque;
 575
 576     close(s->fds[0]);
 577     close(s->fds[1]);
 578     qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], NULL, NULL, NULL, NULL);
 579
 580     rbd_close(s->image);
 581     rados_ioctx_destroy(s->io_ctx);
 582     g_free(s->snap);
 583     rados_shutdown(s->cluster);
 584 }
 585
 586 /*
 587  * Cancel aio. Since we don't reference acb in a non qemu threads,
 588  * it is safe to access it here.
 589  */
 590 static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb)
 591 {
 592     RBDAIOCB *acb = (RBDAIOCB *) blockacb;
 593     acb->cancelled = 1;
 594
 595     while (acb->status == -EINPROGRESS) {
 596         qemu_aio_wait();
 597     }
 598
 599     qemu_aio_release(acb);
 600 }
 601
 602 static const AIOCBInfo rbd_aiocb_info = {
 603     .aiocb_size = sizeof(RBDAIOCB),
 604     .cancel = qemu_rbd_aio_cancel,
 605 };
 606
 607 static int qemu_rbd_send_pipe(BDRVRBDState *s, RADOSCB *rcb)
 608 {
 609     int ret = 0;
 610     while (1) {
 611         fd_set wfd;
 612         int fd = s->fds[RBD_FD_WRITE];
 613
 614         /* send the op pointer to the qemu thread that is responsible
 615            for the aio/op completion. Must do it in a qemu thread context */
 616         ret = write(fd, (void *)&rcb, sizeof(rcb));
 617         if (ret >= 0) {
 618             break;
 619         }
 620         if (errno == EINTR) {
 621             continue;
 622         }
 623         if (errno != EAGAIN) {
 624             break;
 625         }
 626
 627         FD_ZERO(&wfd);
 628         FD_SET(fd, &wfd);
 629         do {
 630             ret = select(fd + 1, NULL, &wfd, NULL, NULL);
 631         } while (ret < 0 && errno == EINTR);
 632     }
 633
 634     return ret;
 635 }
 636
 637 /*
 638  * This is the callback function for rbd_aio_read and _write
 639  *
 640  * Note: this function is being called from a non qemu thread so
 641  * we need to be careful about what we do here. Generally we only
 642  * write to the block notification pipe, and do the rest of the
 643  * io completion handling from qemu_rbd_aio_event_reader() which
 644  * runs in a qemu context.
 645  */
 646 static void rbd_finish_aiocb(rbd_completion_t c, RADOSCB *rcb)
 647 {
 648     int ret;
 649     rcb->ret = rbd_aio_get_return_value(c);
 650     rbd_aio_release(c);
 651     ret = qemu_rbd_send_pipe(rcb->s, rcb);
 652     if (ret < 0) {
 653         error_report("failed writing to acb->s->fds");
 654         g_free(rcb);
 655     }
 656 }
 657
 658 /* Callback when all queued rbd_aio requests are complete */
 659
 660 static void rbd_aio_bh_cb(void *opaque)
 661 {
 662     RBDAIOCB *acb = opaque;
 663
 664     if (acb->cmd == RBD_AIO_READ) {
 665         qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
 666     }
 667     qemu_vfree(acb->bounce);
 668     acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
 669     qemu_bh_delete(acb->bh);
 670     acb->bh = NULL;
 671     acb->status = 0;
 672
 673     if (!acb->cancelled) {
 674         qemu_aio_release(acb);
 675     }
 676 }
 677
 678 static int rbd_aio_discard_wrapper(rbd_image_t image,
 679                                    uint64_t off,
 680                                    uint64_t len,
 681                                    rbd_completion_t comp)
 682 {
 683 #ifdef LIBRBD_SUPPORTS_DISCARD
 684     return rbd_aio_discard(image, off, len, comp);
 685 #else
 686     return -ENOTSUP;
 687 #endif
 688 }
 689
 690 static int rbd_aio_flush_wrapper(rbd_image_t image,
 691                                  rbd_completion_t comp)
 692 {
 693 #ifdef LIBRBD_SUPPORTS_AIO_FLUSH
 694     return rbd_aio_flush(image, comp);
 695 #else
 696     return -ENOTSUP;
 697 #endif
 698 }
 699
 700 static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs,
 701                                        int64_t sector_num,
 702                                        QEMUIOVector *qiov,
 703                                        int nb_sectors,
 704                                        BlockDriverCompletionFunc *cb,
 705                                        void *opaque,
 706                                        RBDAIOCmd cmd)
 707 {
 708     RBDAIOCB *acb;
 709     RADOSCB *rcb;
 710     rbd_completion_t c;
 711     int64_t off, size;
 712     char *buf;
 713     int r;
 714
 715     BDRVRBDState *s = bs->opaque;
 716
 717     acb = qemu_aio_get(&rbd_aiocb_info, bs, cb, opaque);
 718     acb->cmd = cmd;
 719     acb->qiov = qiov;
 720     if (cmd == RBD_AIO_DISCARD || cmd == RBD_AIO_FLUSH) {
 721         acb->bounce = NULL;
 722     } else {
 723         acb->bounce = qemu_blockalign(bs, qiov->size);
 724     }
 725     acb->ret = 0;
 726     acb->error = 0;
 727     acb->s = s;
 728     acb->cancelled = 0;
 729     acb->bh = NULL;
 730     acb->status = -EINPROGRESS;
 731
 732     if (cmd == RBD_AIO_WRITE) {
 733         qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
 734     }
 735
 736     buf = acb->bounce;
 737
 738     off = sector_num * BDRV_SECTOR_SIZE;
 739     size = nb_sectors * BDRV_SECTOR_SIZE;
 740
 741     s->qemu_aio_count++; /* All the RADOSCB */
 742
 743     rcb = g_malloc(sizeof(RADOSCB));
 744     rcb->done = 0;
 745     rcb->acb = acb;
 746     rcb->buf = buf;
 747     rcb->s = acb->s;
 748     rcb->size = size;
 749     r = rbd_aio_create_completion(rcb, (rbd_callback_t) rbd_finish_aiocb, &c);
 750     if (r < 0) {
 751         goto failed;
 752     }
 753
 754     switch (cmd) {
 755     case RBD_AIO_WRITE:
 756         r = rbd_aio_write(s->image, off, size, buf, c);
 757         break;
 758     case RBD_AIO_READ:
 759         r = rbd_aio_read(s->image, off, size, buf, c);
 760         break;
 761     case RBD_AIO_DISCARD:
 762         r = rbd_aio_discard_wrapper(s->image, off, size, c);
 763         break;
 764     case RBD_AIO_FLUSH:
 765         r = rbd_aio_flush_wrapper(s->image, c);
 766         break;
 767     default:
 768         r = -EINVAL;
 769     }
 770
 771     if (r < 0) {
 772         goto failed;
 773     }
 774
 775     return &acb->common;
 776
 777 failed:
 778     g_free(rcb);
 779     s->qemu_aio_count--;
 780     qemu_aio_release(acb);
 781     return NULL;
 782 }
 783
 784 static BlockDriverAIOCB *qemu_rbd_aio_readv(BlockDriverState *bs,
 785                                             int64_t sector_num,
 786                                             QEMUIOVector *qiov,
 787                                             int nb_sectors,
 788                                             BlockDriverCompletionFunc *cb,
 789                                             void *opaque)
 790 {
 791     return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
 792                          RBD_AIO_READ);
 793 }
 794
 795 static BlockDriverAIOCB *qemu_rbd_aio_writev(BlockDriverState *bs,
 796                                              int64_t sector_num,
 797                                              QEMUIOVector *qiov,
 798                                              int nb_sectors,
 799                                              BlockDriverCompletionFunc *cb,
 800                                              void *opaque)
 801 {
 802     return rbd_start_aio(bs, sector_num, qiov, nb_sectors, cb, opaque,
 803                          RBD_AIO_WRITE);
 804 }
 805
 806 #ifdef LIBRBD_SUPPORTS_AIO_FLUSH
 807 static BlockDriverAIOCB *qemu_rbd_aio_flush(BlockDriverState *bs,
 808                                             BlockDriverCompletionFunc *cb,
 809                                             void *opaque)
 810 {
 811     return rbd_start_aio(bs, 0, NULL, 0, cb, opaque, RBD_AIO_FLUSH);
 812 }
 813
 814 #else
 815
 816 static int qemu_rbd_co_flush(BlockDriverState *bs)
 817 {
 818 #if LIBRBD_VERSION_CODE >= LIBRBD_VERSION(0, 1, 1)
 819     /* rbd_flush added in 0.1.1 */
 820     BDRVRBDState *s = bs->opaque;
 821     return rbd_flush(s->image);
 822 #else
 823     return 0;
 824 #endif
 825 }
 826 #endif
 827
 828 static int qemu_rbd_getinfo(BlockDriverState *bs, BlockDriverInfo *bdi)
 829 {
 830     BDRVRBDState *s = bs->opaque;
 831     rbd_image_info_t info;
 832     int r;
 833
 834     r = rbd_stat(s->image, &info, sizeof(info));
 835     if (r < 0) {
 836         return r;
 837     }
 838
 839     bdi->cluster_size = info.obj_size;
 840     return 0;
 841 }
 842
 843 static int64_t qemu_rbd_getlength(BlockDriverState *bs)
 844 {
 845     BDRVRBDState *s = bs->opaque;
 846     rbd_image_info_t info;
 847     int r;
 848
 849     r = rbd_stat(s->image, &info, sizeof(info));
 850     if (r < 0) {
 851         return r;
 852     }
 853
 854     return info.size;
 855 }
 856
 857 static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
 858 {
 859     BDRVRBDState *s = bs->opaque;
 860     int r;
 861
 862     r = rbd_resize(s->image, offset);
 863     if (r < 0) {
 864         return r;
 865     }
 866
 867     return 0;
 868 }
 869
 870 static int qemu_rbd_snap_create(BlockDriverState *bs,
 871                                 QEMUSnapshotInfo *sn_info)
 872 {
 873     BDRVRBDState *s = bs->opaque;
 874     int r;
 875
 876     if (sn_info->name[0] == '\0') {
 877         return -EINVAL; /* we need a name for rbd snapshots */
 878     }
 879
 880     /*
 881      * rbd snapshots are using the name as the user controlled unique identifier
 882      * we can't use the rbd snapid for that purpose, as it can't be set
 883      */
 884     if (sn_info->id_str[0] != '\0' &&
 885         strcmp(sn_info->id_str, sn_info->name) != 0) {
 886         return -EINVAL;
 887     }
 888
 889     if (strlen(sn_info->name) >= sizeof(sn_info->id_str)) {
 890         return -ERANGE;
 891     }
 892
 893     r = rbd_snap_create(s->image, sn_info->name);
 894     if (r < 0) {
 895         error_report("failed to create snap: %s", strerror(-r));
 896         return r;
 897     }
 898
 899     return 0;
 900 }
 901
 902 static int qemu_rbd_snap_remove(BlockDriverState *bs,
 903                                 const char *snapshot_name)
 904 {
 905     BDRVRBDState *s = bs->opaque;
 906     int r;
 907
 908     r = rbd_snap_remove(s->image, snapshot_name);
 909     return r;
 910 }
 911
 912 static int qemu_rbd_snap_rollback(BlockDriverState *bs,
 913                                   const char *snapshot_name)
 914 {
 915     BDRVRBDState *s = bs->opaque;
 916     int r;
 917
 918     r = rbd_snap_rollback(s->image, snapshot_name);
 919     return r;
 920 }
 921
 922 static int qemu_rbd_snap_list(BlockDriverState *bs,
 923                               QEMUSnapshotInfo **psn_tab)
 924 {
 925     BDRVRBDState *s = bs->opaque;
 926     QEMUSnapshotInfo *sn_info, *sn_tab = NULL;
 927     int i, snap_count;
 928     rbd_snap_info_t *snaps;
 929     int max_snaps = RBD_MAX_SNAPS;
 930
 931     do {
 932         snaps = g_malloc(sizeof(*snaps) * max_snaps);
 933         snap_count = rbd_snap_list(s->image, snaps, &max_snaps);
 934         if (snap_count < 0) {
 935             g_free(snaps);
 936         }
 937     } while (snap_count == -ERANGE);
 938
 939     if (snap_count <= 0) {
 940         goto done;
 941     }
 942
 943     sn_tab = g_malloc0(snap_count * sizeof(QEMUSnapshotInfo));
 944
 945     for (i = 0; i < snap_count; i++) {
 946         const char *snap_name = snaps[i].name;
 947
 948         sn_info = sn_tab + i;
 949         pstrcpy(sn_info->id_str, sizeof(sn_info->id_str), snap_name);
 950         pstrcpy(sn_info->name, sizeof(sn_info->name), snap_name);
 951
 952         sn_info->vm_state_size = snaps[i].size;
 953         sn_info->date_sec = 0;
 954         sn_info->date_nsec = 0;
 955         sn_info->vm_clock_nsec = 0;
 956     }
 957     rbd_snap_list_end(snaps);
 958
 959  done:
 960     *psn_tab = sn_tab;
 961     return snap_count;
 962 }
 963
 964 #ifdef LIBRBD_SUPPORTS_DISCARD
 965 static BlockDriverAIOCB* qemu_rbd_aio_discard(BlockDriverState *bs,
 966                                               int64_t sector_num,
 967                                               int nb_sectors,
 968                                               BlockDriverCompletionFunc *cb,
 969                                               void *opaque)
 970 {
 971     return rbd_start_aio(bs, sector_num, NULL, nb_sectors, cb, opaque,
 972                          RBD_AIO_DISCARD);
 973 }
 974 #endif
 975
 976 static QEMUOptionParameter qemu_rbd_create_options[] = {
 977     {
 978      .name = BLOCK_OPT_SIZE,
 979      .type = OPT_SIZE,
 980      .help = "Virtual disk size"
 981     },
 982     {
 983      .name = BLOCK_OPT_CLUSTER_SIZE,
 984      .type = OPT_SIZE,
 985      .help = "RBD object size"
 986     },
 987     {NULL}
 988 };
 989
 990 static BlockDriver bdrv_rbd = {
 991     .format_name        = "rbd",
 992     .instance_size      = sizeof(BDRVRBDState),
 993     .bdrv_file_open     = qemu_rbd_open,
 994     .bdrv_close         = qemu_rbd_close,
 995     .bdrv_create        = qemu_rbd_create,
 996     .bdrv_get_info      = qemu_rbd_getinfo,
 997     .create_options     = qemu_rbd_create_options,
 998     .bdrv_getlength     = qemu_rbd_getlength,
 999     .bdrv_truncate      = qemu_rbd_truncate,
1000     .protocol_name      = "rbd",
1001
1002     .bdrv_aio_readv         = qemu_rbd_aio_readv,
1003     .bdrv_aio_writev        = qemu_rbd_aio_writev,
1004
1005 #ifdef LIBRBD_SUPPORTS_AIO_FLUSH
1006     .bdrv_aio_flush         = qemu_rbd_aio_flush,
1007 #else
1008     .bdrv_co_flush_to_disk  = qemu_rbd_co_flush,
1009 #endif
1010
1011 #ifdef LIBRBD_SUPPORTS_DISCARD
1012     .bdrv_aio_discard       = qemu_rbd_aio_discard,
1013 #endif
1014
1015     .bdrv_snapshot_create   = qemu_rbd_snap_create,
1016     .bdrv_snapshot_delete   = qemu_rbd_snap_remove,
1017     .bdrv_snapshot_list     = qemu_rbd_snap_list,
1018     .bdrv_snapshot_goto     = qemu_rbd_snap_rollback,
1019 };
1020
1021 static void bdrv_rbd_init(void)
1022 {
1023     bdrv_register(&bdrv_rbd);
1024 }
1025
1026 block_init(bdrv_rbd_init);