blockdev.c

   1 /*
   2  * QEMU host block devices
   3  *
   4  * Copyright (c) 2003-2008 Fabrice Bellard
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or
   7  * later.  See the COPYING file in the top-level directory.
   8  */
   9
  10 #include "block.h"
  11 #include "blockdev.h"
  12 #include "monitor.h"
  13 #include "qerror.h"
  14 #include "qemu-option.h"
  15 #include "qemu-config.h"
  16 #include "sysemu.h"
  17 #include "hw/qdev.h"
  18 #include "block_int.h"
  19
  20 static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
  21
  22 /*
  23  * We automatically delete the drive when a device using it gets
  24  * unplugged.  Questionable feature, but we can't just drop it.
  25  * Device models call blockdev_mark_auto_del() to schedule the
  26  * automatic deletion, and generic qdev code calls blockdev_auto_del()
  27  * when deletion is actually safe.
  28  */
  29 void blockdev_mark_auto_del(BlockDriverState *bs)
  30 {
  31     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  32
  33     if (dinfo) {
  34         dinfo->auto_del = 1;
  35     }
  36 }
  37
  38 void blockdev_auto_del(BlockDriverState *bs)
  39 {
  40     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  41
  42     if (dinfo && dinfo->auto_del) {
  43         drive_uninit(dinfo);
  44     }
  45 }
  46
  47 QemuOpts *drive_add(const char *file, const char *fmt, ...)
  48 {
  49     va_list ap;
  50     char optstr[1024];
  51     QemuOpts *opts;
  52
  53     va_start(ap, fmt);
  54     vsnprintf(optstr, sizeof(optstr), fmt, ap);
  55     va_end(ap);
  56
  57     opts = qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
  58     if (!opts) {
  59         return NULL;
  60     }
  61     if (file)
  62         qemu_opt_set(opts, "file", file);
  63     return opts;
  64 }
  65
  66 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
  67 {
  68     DriveInfo *dinfo;
  69
  70     /* seek interface, bus and unit */
  71
  72     QTAILQ_FOREACH(dinfo, &drives, next) {
  73         if (dinfo->type == type &&
  74             dinfo->bus == bus &&
  75             dinfo->unit == unit)
  76             return dinfo;
  77     }
  78
  79     return NULL;
  80 }
  81
  82 int drive_get_max_bus(BlockInterfaceType type)
  83 {
  84     int max_bus;
  85     DriveInfo *dinfo;
  86
  87     max_bus = -1;
  88     QTAILQ_FOREACH(dinfo, &drives, next) {
  89         if(dinfo->type == type &&
  90            dinfo->bus > max_bus)
  91             max_bus = dinfo->bus;
  92     }
  93     return max_bus;
  94 }
  95
  96 DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
  97 {
  98     DriveInfo *dinfo;
  99
 100     QTAILQ_FOREACH(dinfo, &drives, next) {
 101         if (dinfo->bdrv == bs) {
 102             return dinfo;
 103         }
 104     }
 105     return NULL;
 106 }
 107
 108 static void bdrv_format_print(void *opaque, const char *name)
 109 {
 110     fprintf(stderr, " %s", name);
 111 }
 112
 113 void drive_uninit(DriveInfo *dinfo)
 114 {
 115     qemu_opts_del(dinfo->opts);
 116     bdrv_delete(dinfo->bdrv);
 117     QTAILQ_REMOVE(&drives, dinfo, next);
 118     qemu_free(dinfo);
 119 }
 120
 121 static int parse_block_error_action(const char *buf, int is_read)
 122 {
 123     if (!strcmp(buf, "ignore")) {
 124         return BLOCK_ERR_IGNORE;
 125     } else if (!is_read && !strcmp(buf, "enospc")) {
 126         return BLOCK_ERR_STOP_ENOSPC;
 127     } else if (!strcmp(buf, "stop")) {
 128         return BLOCK_ERR_STOP_ANY;
 129     } else if (!strcmp(buf, "report")) {
 130         return BLOCK_ERR_REPORT;
 131     } else {
 132         fprintf(stderr, "qemu: '%s' invalid %s error action\n",
 133             buf, is_read ? "read" : "write");
 134         return -1;
 135     }
 136 }
 137
 138 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi, int *fatal_error)
 139 {
 140     const char *buf;
 141     const char *file = NULL;
 142     char devname[128];
 143     const char *serial;
 144     const char *mediastr = "";
 145     BlockInterfaceType type;
 146     enum { MEDIA_DISK, MEDIA_CDROM } media;
 147     int bus_id, unit_id;
 148     int cyls, heads, secs, translation;
 149     BlockDriver *drv = NULL;
 150     int max_devs;
 151     int index;
 152     int ro = 0;
 153     int bdrv_flags = 0;
 154     int on_read_error, on_write_error;
 155     const char *devaddr;
 156     DriveInfo *dinfo;
 157     int snapshot = 0;
 158     int ret;
 159
 160     *fatal_error = 1;
 161
 162     translation = BIOS_ATA_TRANSLATION_AUTO;
 163
 164     if (default_to_scsi) {
 165         type = IF_SCSI;
 166         max_devs = MAX_SCSI_DEVS;
 167         pstrcpy(devname, sizeof(devname), "scsi");
 168     } else {
 169         type = IF_IDE;
 170         max_devs = MAX_IDE_DEVS;
 171         pstrcpy(devname, sizeof(devname), "ide");
 172     }
 173     media = MEDIA_DISK;
 174
 175     /* extract parameters */
 176     bus_id  = qemu_opt_get_number(opts, "bus", 0);
 177     unit_id = qemu_opt_get_number(opts, "unit", -1);
 178     index   = qemu_opt_get_number(opts, "index", -1);
 179
 180     cyls  = qemu_opt_get_number(opts, "cyls", 0);
 181     heads = qemu_opt_get_number(opts, "heads", 0);
 182     secs  = qemu_opt_get_number(opts, "secs", 0);
 183
 184     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 185     ro = qemu_opt_get_bool(opts, "readonly", 0);
 186
 187     file = qemu_opt_get(opts, "file");
 188     serial = qemu_opt_get(opts, "serial");
 189
 190     if ((buf = qemu_opt_get(opts, "if")) != NULL) {
 191         pstrcpy(devname, sizeof(devname), buf);
 192         if (!strcmp(buf, "ide")) {
 193             type = IF_IDE;
 194             max_devs = MAX_IDE_DEVS;
 195         } else if (!strcmp(buf, "scsi")) {
 196             type = IF_SCSI;
 197             max_devs = MAX_SCSI_DEVS;
 198         } else if (!strcmp(buf, "floppy")) {
 199             type = IF_FLOPPY;
 200             max_devs = 0;
 201         } else if (!strcmp(buf, "pflash")) {
 202             type = IF_PFLASH;
 203             max_devs = 0;
 204         } else if (!strcmp(buf, "mtd")) {
 205             type = IF_MTD;
 206             max_devs = 0;
 207         } else if (!strcmp(buf, "sd")) {
 208             type = IF_SD;
 209             max_devs = 0;
 210         } else if (!strcmp(buf, "virtio")) {
 211             type = IF_VIRTIO;
 212             max_devs = 0;
 213         } else if (!strcmp(buf, "xen")) {
 214             type = IF_XEN;
 215             max_devs = 0;
 216         } else if (!strcmp(buf, "none")) {
 217             type = IF_NONE;
 218             max_devs = 0;
 219         } else {
 220             fprintf(stderr, "qemu: unsupported bus type '%s'\n", buf);
 221             return NULL;
 222         }
 223     }
 224
 225     if (cyls || heads || secs) {
 226         if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
 227             fprintf(stderr, "qemu: '%s' invalid physical cyls number\n", buf);
 228             return NULL;
 229         }
 230         if (heads < 1 || (type == IF_IDE && heads > 16)) {
 231             fprintf(stderr, "qemu: '%s' invalid physical heads number\n", buf);
 232             return NULL;
 233         }
 234         if (secs < 1 || (type == IF_IDE && secs > 63)) {
 235             fprintf(stderr, "qemu: '%s' invalid physical secs number\n", buf);
 236             return NULL;
 237         }
 238     }
 239
 240     if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
 241         if (!cyls) {
 242             fprintf(stderr,
 243                     "qemu: '%s' trans must be used with cyls,heads and secs\n",
 244                     buf);
 245             return NULL;
 246         }
 247         if (!strcmp(buf, "none"))
 248             translation = BIOS_ATA_TRANSLATION_NONE;
 249         else if (!strcmp(buf, "lba"))
 250             translation = BIOS_ATA_TRANSLATION_LBA;
 251         else if (!strcmp(buf, "auto"))
 252             translation = BIOS_ATA_TRANSLATION_AUTO;
 253         else {
 254             fprintf(stderr, "qemu: '%s' invalid translation type\n", buf);
 255             return NULL;
 256         }
 257     }
 258
 259     if ((buf = qemu_opt_get(opts, "media")) != NULL) {
 260         if (!strcmp(buf, "disk")) {
 261             media = MEDIA_DISK;
 262         } else if (!strcmp(buf, "cdrom")) {
 263             if (cyls || secs || heads) {
 264                 fprintf(stderr,
 265                         "qemu: '%s' invalid physical CHS format\n", buf);
 266                 return NULL;
 267             }
 268             media = MEDIA_CDROM;
 269         } else {
 270             fprintf(stderr, "qemu: '%s' invalid media\n", buf);
 271             return NULL;
 272         }
 273     }
 274
 275     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
 276         if (!strcmp(buf, "off") || !strcmp(buf, "none")) {
 277             bdrv_flags |= BDRV_O_NOCACHE;
 278         } else if (!strcmp(buf, "writeback")) {
 279             bdrv_flags |= BDRV_O_CACHE_WB;
 280         } else if (!strcmp(buf, "unsafe")) {
 281             bdrv_flags |= BDRV_O_CACHE_WB;
 282             bdrv_flags |= BDRV_O_NO_FLUSH;
 283         } else if (!strcmp(buf, "writethrough")) {
 284             /* this is the default */
 285         } else {
 286            fprintf(stderr, "qemu: invalid cache option\n");
 287            return NULL;
 288         }
 289     }
 290
 291 #ifdef CONFIG_LINUX_AIO
 292     if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
 293         if (!strcmp(buf, "native")) {
 294             bdrv_flags |= BDRV_O_NATIVE_AIO;
 295         } else if (!strcmp(buf, "threads")) {
 296             /* this is the default */
 297         } else {
 298            fprintf(stderr, "qemu: invalid aio option\n");
 299            return NULL;
 300         }
 301     }
 302 #endif
 303
 304     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
 305        if (strcmp(buf, "?") == 0) {
 306             fprintf(stderr, "qemu: Supported formats:");
 307             bdrv_iterate_format(bdrv_format_print, NULL);
 308             fprintf(stderr, "\n");
 309             return NULL;
 310         }
 311         drv = bdrv_find_whitelisted_format(buf);
 312         if (!drv) {
 313             fprintf(stderr, "qemu: '%s' invalid format\n", buf);
 314             return NULL;
 315         }
 316     }
 317
 318     on_write_error = BLOCK_ERR_STOP_ENOSPC;
 319     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
 320         if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
 321             fprintf(stderr, "werror is not supported by this format\n");
 322             return NULL;
 323         }
 324
 325         on_write_error = parse_block_error_action(buf, 0);
 326         if (on_write_error < 0) {
 327             return NULL;
 328         }
 329     }
 330
 331     on_read_error = BLOCK_ERR_REPORT;
 332     if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
 333         if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
 334             fprintf(stderr, "rerror is not supported by this format\n");
 335             return NULL;
 336         }
 337
 338         on_read_error = parse_block_error_action(buf, 1);
 339         if (on_read_error < 0) {
 340             return NULL;
 341         }
 342     }
 343
 344     if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
 345         if (type != IF_VIRTIO) {
 346             fprintf(stderr, "addr is not supported\n");
 347             return NULL;
 348         }
 349     }
 350
 351     /* compute bus and unit according index */
 352
 353     if (index != -1) {
 354         if (bus_id != 0 || unit_id != -1) {
 355             fprintf(stderr,
 356                     "qemu: index cannot be used with bus and unit\n");
 357             return NULL;
 358         }
 359         if (max_devs == 0)
 360         {
 361             unit_id = index;
 362             bus_id = 0;
 363         } else {
 364             unit_id = index % max_devs;
 365             bus_id = index / max_devs;
 366         }
 367     }
 368
 369     /* if user doesn't specify a unit_id,
 370      * try to find the first free
 371      */
 372
 373     if (unit_id == -1) {
 374        unit_id = 0;
 375        while (drive_get(type, bus_id, unit_id) != NULL) {
 376            unit_id++;
 377            if (max_devs && unit_id >= max_devs) {
 378                unit_id -= max_devs;
 379                bus_id++;
 380            }
 381        }
 382     }
 383
 384     /* check unit id */
 385
 386     if (max_devs && unit_id >= max_devs) {
 387         fprintf(stderr, "qemu: unit %d too big (max is %d)\n",
 388                 unit_id, max_devs - 1);
 389         return NULL;
 390     }
 391
 392     /*
 393      * ignore multiple definitions
 394      */
 395
 396     if (drive_get(type, bus_id, unit_id) != NULL) {
 397         *fatal_error = 0;
 398         return NULL;
 399     }
 400
 401     /* init */
 402
 403     dinfo = qemu_mallocz(sizeof(*dinfo));
 404     if ((buf = qemu_opts_id(opts)) != NULL) {
 405         dinfo->id = qemu_strdup(buf);
 406     } else {
 407         /* no id supplied -> create one */
 408         dinfo->id = qemu_mallocz(32);
 409         if (type == IF_IDE || type == IF_SCSI)
 410             mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
 411         if (max_devs)
 412             snprintf(dinfo->id, 32, "%s%i%s%i",
 413                      devname, bus_id, mediastr, unit_id);
 414         else
 415             snprintf(dinfo->id, 32, "%s%s%i",
 416                      devname, mediastr, unit_id);
 417     }
 418     dinfo->bdrv = bdrv_new(dinfo->id);
 419     dinfo->devaddr = devaddr;
 420     dinfo->type = type;
 421     dinfo->bus = bus_id;
 422     dinfo->unit = unit_id;
 423     dinfo->opts = opts;
 424     if (serial)
 425         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
 426     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 427
 428     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 429
 430     switch(type) {
 431     case IF_IDE:
 432     case IF_SCSI:
 433     case IF_XEN:
 434     case IF_NONE:
 435         switch(media) {
 436         case MEDIA_DISK:
 437             if (cyls != 0) {
 438                 bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
 439                 bdrv_set_translation_hint(dinfo->bdrv, translation);
 440             }
 441             break;
 442         case MEDIA_CDROM:
 443             bdrv_set_type_hint(dinfo->bdrv, BDRV_TYPE_CDROM);
 444             break;
 445         }
 446         break;
 447     case IF_SD:
 448         /* FIXME: This isn't really a floppy, but it's a reasonable
 449            approximation.  */
 450     case IF_FLOPPY:
 451         bdrv_set_type_hint(dinfo->bdrv, BDRV_TYPE_FLOPPY);
 452         break;
 453     case IF_PFLASH:
 454     case IF_MTD:
 455         break;
 456     case IF_VIRTIO:
 457         /* add virtio block device */
 458         opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
 459         qemu_opt_set(opts, "driver", "virtio-blk-pci");
 460         qemu_opt_set(opts, "drive", dinfo->id);
 461         if (devaddr)
 462             qemu_opt_set(opts, "addr", devaddr);
 463         break;
 464     case IF_COUNT:
 465         abort();
 466     }
 467     if (!file || !*file) {
 468         *fatal_error = 0;
 469         return NULL;
 470     }
 471     if (snapshot) {
 472         /* always use cache=unsafe with snapshot */
 473         bdrv_flags &= ~BDRV_O_CACHE_MASK;
 474         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
 475     }
 476
 477     if (media == MEDIA_CDROM) {
 478         /* CDROM is fine for any interface, don't check.  */
 479         ro = 1;
 480     } else if (ro == 1) {
 481         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
 482             fprintf(stderr, "qemu: readonly flag not supported for drive with this interface\n");
 483             return NULL;
 484         }
 485     }
 486
 487     bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
 488
 489     ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
 490     if (ret < 0) {
 491         fprintf(stderr, "qemu: could not open disk image %s: %s\n",
 492                         file, strerror(-ret));
 493         return NULL;
 494     }
 495
 496     if (bdrv_key_required(dinfo->bdrv))
 497         autostart = 0;
 498     *fatal_error = 0;
 499     return dinfo;
 500 }
 501
 502 void do_commit(Monitor *mon, const QDict *qdict)
 503 {
 504     const char *device = qdict_get_str(qdict, "device");
 505     BlockDriverState *bs;
 506
 507     if (!strcmp(device, "all")) {
 508         bdrv_commit_all();
 509     } else {
 510         bs = bdrv_find(device);
 511         if (!bs) {
 512             qerror_report(QERR_DEVICE_NOT_FOUND, device);
 513             return;
 514         }
 515         bdrv_commit(bs);
 516     }
 517 }
 518
 519 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
 520 {
 521     const char *device = qdict_get_str(qdict, "device");
 522     const char *filename = qdict_get_try_str(qdict, "snapshot_file");
 523     const char *format = qdict_get_try_str(qdict, "format");
 524     BlockDriverState *bs;
 525     BlockDriver *drv, *proto_drv;
 526     int ret = 0;
 527     int flags;
 528
 529     bs = bdrv_find(device);
 530     if (!bs) {
 531         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 532         ret = -1;
 533         goto out;
 534     }
 535
 536     if (!format) {
 537         format = "qcow2";
 538     }
 539
 540     drv = bdrv_find_format(format);
 541     if (!drv) {
 542         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 543         ret = -1;
 544         goto out;
 545     }
 546
 547     proto_drv = bdrv_find_protocol(filename);
 548     if (!proto_drv) {
 549         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 550         ret = -1;
 551         goto out;
 552     }
 553
 554     ret = bdrv_img_create(filename, format, bs->filename,
 555                           bs->drv->format_name, NULL, -1, bs->open_flags);
 556     if (ret) {
 557         goto out;
 558     }
 559
 560     qemu_aio_flush();
 561     bdrv_flush(bs);
 562
 563     flags = bs->open_flags;
 564     bdrv_close(bs);
 565     ret = bdrv_open(bs, filename, flags, drv);
 566     /*
 567      * If reopening the image file we just created fails, we really
 568      * are in trouble :(
 569      */
 570     if (ret != 0) {
 571         abort();
 572     }
 573 out:
 574     if (ret) {
 575         ret = -1;
 576     }
 577
 578     return ret;
 579 }
 580
 581 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 582 {
 583     if (!force) {
 584         if (!bdrv_is_removable(bs)) {
 585             qerror_report(QERR_DEVICE_NOT_REMOVABLE,
 586                            bdrv_get_device_name(bs));
 587             return -1;
 588         }
 589         if (bdrv_is_locked(bs)) {
 590             qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
 591             return -1;
 592         }
 593     }
 594     bdrv_close(bs);
 595     return 0;
 596 }
 597
 598 int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
 599 {
 600     BlockDriverState *bs;
 601     int force = qdict_get_try_bool(qdict, "force", 0);
 602     const char *filename = qdict_get_str(qdict, "device");
 603
 604     bs = bdrv_find(filename);
 605     if (!bs) {
 606         qerror_report(QERR_DEVICE_NOT_FOUND, filename);
 607         return -1;
 608     }
 609     return eject_device(mon, bs, force);
 610 }
 611
 612 int do_block_set_passwd(Monitor *mon, const QDict *qdict,
 613                         QObject **ret_data)
 614 {
 615     BlockDriverState *bs;
 616     int err;
 617
 618     bs = bdrv_find(qdict_get_str(qdict, "device"));
 619     if (!bs) {
 620         qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
 621         return -1;
 622     }
 623
 624     err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
 625     if (err == -EINVAL) {
 626         qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
 627         return -1;
 628     } else if (err < 0) {
 629         qerror_report(QERR_INVALID_PASSWORD);
 630         return -1;
 631     }
 632
 633     return 0;
 634 }
 635
 636 int do_change_block(Monitor *mon, const char *device,
 637                     const char *filename, const char *fmt)
 638 {
 639     BlockDriverState *bs;
 640     BlockDriver *drv = NULL;
 641     int bdrv_flags;
 642
 643     bs = bdrv_find(device);
 644     if (!bs) {
 645         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 646         return -1;
 647     }
 648     if (fmt) {
 649         drv = bdrv_find_whitelisted_format(fmt);
 650         if (!drv) {
 651             qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
 652             return -1;
 653         }
 654     }
 655     if (eject_device(mon, bs, 0) < 0) {
 656         return -1;
 657     }
 658     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
 659     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 660     if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
 661         qerror_report(QERR_OPEN_FILE_FAILED, filename);
 662         return -1;
 663     }
 664     return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
 665 }
 666
 667 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 668 {
 669     const char *id = qdict_get_str(qdict, "id");
 670     BlockDriverState *bs;
 671     BlockDriverState **ptr;
 672     Property *prop;
 673
 674     bs = bdrv_find(id);
 675     if (!bs) {
 676         qerror_report(QERR_DEVICE_NOT_FOUND, id);
 677         return -1;
 678     }
 679
 680     /* quiesce block driver; prevent further io */
 681     qemu_aio_flush();
 682     bdrv_flush(bs);
 683     bdrv_close(bs);
 684
 685     /* clean up guest state from pointing to host resource by
 686      * finding and removing DeviceState "drive" property */
 687     for (prop = bs->peer->info->props; prop && prop->name; prop++) {
 688         if (prop->info->type == PROP_TYPE_DRIVE) {
 689             ptr = qdev_get_prop_ptr(bs->peer, prop);
 690             if ((*ptr) == bs) {
 691                 bdrv_detach(bs, bs->peer);
 692                 *ptr = NULL;
 693                 break;
 694             }
 695         }
 696     }
 697
 698     /* clean up host side */
 699     drive_uninit(drive_get_by_blockdev(bs));
 700
 701     return 0;
 702 }