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 static const char *const if_name[IF_COUNT] = {
  23     [IF_NONE] = "none",
  24     [IF_IDE] = "ide",
  25     [IF_SCSI] = "scsi",
  26     [IF_FLOPPY] = "floppy",
  27     [IF_PFLASH] = "pflash",
  28     [IF_MTD] = "mtd",
  29     [IF_SD] = "sd",
  30     [IF_VIRTIO] = "virtio",
  31     [IF_XEN] = "xen",
  32 };
  33
  34 static const int if_max_devs[IF_COUNT] = {
  35     /*
  36      * Do not change these numbers!  They govern how drive option
  37      * index maps to unit and bus.  That mapping is ABI.
  38      *
  39      * All controllers used to imlement if=T drives need to support
  40      * if_max_devs[T] units, for any T with if_max_devs[T] != 0.
  41      * Otherwise, some index values map to "impossible" bus, unit
  42      * values.
  43      *
  44      * For instance, if you change [IF_SCSI] to 255, -drive
  45      * if=scsi,index=12 no longer means bus=1,unit=5, but
  46      * bus=0,unit=12.  With an lsi53c895a controller (7 units max),
  47      * the drive can't be set up.  Regression.
  48      */
  49     [IF_IDE] = 2,
  50     [IF_SCSI] = 7,
  51 };
  52
  53 /*
  54  * We automatically delete the drive when a device using it gets
  55  * unplugged.  Questionable feature, but we can't just drop it.
  56  * Device models call blockdev_mark_auto_del() to schedule the
  57  * automatic deletion, and generic qdev code calls blockdev_auto_del()
  58  * when deletion is actually safe.
  59  */
  60 void blockdev_mark_auto_del(BlockDriverState *bs)
  61 {
  62     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  63
  64     if (dinfo) {
  65         dinfo->auto_del = 1;
  66     }
  67 }
  68
  69 void blockdev_auto_del(BlockDriverState *bs)
  70 {
  71     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  72
  73     if (dinfo && dinfo->auto_del) {
  74         drive_uninit(dinfo);
  75     }
  76 }
  77
  78 static int drive_index_to_bus_id(BlockInterfaceType type, int index)
  79 {
  80     int max_devs = if_max_devs[type];
  81     return max_devs ? index / max_devs : 0;
  82 }
  83
  84 static int drive_index_to_unit_id(BlockInterfaceType type, int index)
  85 {
  86     int max_devs = if_max_devs[type];
  87     return max_devs ? index % max_devs : index;
  88 }
  89
  90 QemuOpts *drive_def(const char *optstr)
  91 {
  92     return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
  93 }
  94
  95 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
  96                     const char *optstr)
  97 {
  98     QemuOpts *opts;
  99     char buf[32];
 100
 101     opts = drive_def(optstr);
 102     if (!opts) {
 103         return NULL;
 104     }
 105     if (type != IF_DEFAULT) {
 106         qemu_opt_set(opts, "if", if_name[type]);
 107     }
 108     if (index >= 0) {
 109         snprintf(buf, sizeof(buf), "%d", index);
 110         qemu_opt_set(opts, "index", buf);
 111     }
 112     if (file)
 113         qemu_opt_set(opts, "file", file);
 114     return opts;
 115 }
 116
 117 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
 118 {
 119     DriveInfo *dinfo;
 120
 121     /* seek interface, bus and unit */
 122
 123     QTAILQ_FOREACH(dinfo, &drives, next) {
 124         if (dinfo->type == type &&
 125             dinfo->bus == bus &&
 126             dinfo->unit == unit)
 127             return dinfo;
 128     }
 129
 130     return NULL;
 131 }
 132
 133 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)
 134 {
 135     return drive_get(type,
 136                      drive_index_to_bus_id(type, index),
 137                      drive_index_to_unit_id(type, index));
 138 }
 139
 140 int drive_get_max_bus(BlockInterfaceType type)
 141 {
 142     int max_bus;
 143     DriveInfo *dinfo;
 144
 145     max_bus = -1;
 146     QTAILQ_FOREACH(dinfo, &drives, next) {
 147         if(dinfo->type == type &&
 148            dinfo->bus > max_bus)
 149             max_bus = dinfo->bus;
 150     }
 151     return max_bus;
 152 }
 153
 154 /* Get a block device.  This should only be used for single-drive devices
 155    (e.g. SD/Floppy/MTD).  Multi-disk devices (scsi/ide) should use the
 156    appropriate bus.  */
 157 DriveInfo *drive_get_next(BlockInterfaceType type)
 158 {
 159     static int next_block_unit[IF_COUNT];
 160
 161     return drive_get(type, 0, next_block_unit[type]++);
 162 }
 163
 164 DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
 165 {
 166     DriveInfo *dinfo;
 167
 168     QTAILQ_FOREACH(dinfo, &drives, next) {
 169         if (dinfo->bdrv == bs) {
 170             return dinfo;
 171         }
 172     }
 173     return NULL;
 174 }
 175
 176 static void bdrv_format_print(void *opaque, const char *name)
 177 {
 178     error_printf(" %s", name);
 179 }
 180
 181 void drive_uninit(DriveInfo *dinfo)
 182 {
 183     qemu_opts_del(dinfo->opts);
 184     bdrv_delete(dinfo->bdrv);
 185     QTAILQ_REMOVE(&drives, dinfo, next);
 186     qemu_free(dinfo);
 187 }
 188
 189 static int parse_block_error_action(const char *buf, int is_read)
 190 {
 191     if (!strcmp(buf, "ignore")) {
 192         return BLOCK_ERR_IGNORE;
 193     } else if (!is_read && !strcmp(buf, "enospc")) {
 194         return BLOCK_ERR_STOP_ENOSPC;
 195     } else if (!strcmp(buf, "stop")) {
 196         return BLOCK_ERR_STOP_ANY;
 197     } else if (!strcmp(buf, "report")) {
 198         return BLOCK_ERR_REPORT;
 199     } else {
 200         error_report("'%s' invalid %s error action",
 201                      buf, is_read ? "read" : "write");
 202         return -1;
 203     }
 204 }
 205
 206 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
 207 {
 208     const char *buf;
 209     const char *file = NULL;
 210     char devname[128];
 211     const char *serial;
 212     const char *mediastr = "";
 213     BlockInterfaceType type;
 214     enum { MEDIA_DISK, MEDIA_CDROM } media;
 215     int bus_id, unit_id;
 216     int cyls, heads, secs, translation;
 217     BlockDriver *drv = NULL;
 218     int max_devs;
 219     int index;
 220     int ro = 0;
 221     int bdrv_flags = 0;
 222     int on_read_error, on_write_error;
 223     const char *devaddr;
 224     DriveInfo *dinfo;
 225     int snapshot = 0;
 226     int ret;
 227
 228     translation = BIOS_ATA_TRANSLATION_AUTO;
 229
 230     if (default_to_scsi) {
 231         type = IF_SCSI;
 232         pstrcpy(devname, sizeof(devname), "scsi");
 233     } else {
 234         type = IF_IDE;
 235         pstrcpy(devname, sizeof(devname), "ide");
 236     }
 237     media = MEDIA_DISK;
 238
 239     /* extract parameters */
 240     bus_id  = qemu_opt_get_number(opts, "bus", 0);
 241     unit_id = qemu_opt_get_number(opts, "unit", -1);
 242     index   = qemu_opt_get_number(opts, "index", -1);
 243
 244     cyls  = qemu_opt_get_number(opts, "cyls", 0);
 245     heads = qemu_opt_get_number(opts, "heads", 0);
 246     secs  = qemu_opt_get_number(opts, "secs", 0);
 247
 248     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 249     ro = qemu_opt_get_bool(opts, "readonly", 0);
 250
 251     file = qemu_opt_get(opts, "file");
 252     serial = qemu_opt_get(opts, "serial");
 253
 254     if ((buf = qemu_opt_get(opts, "if")) != NULL) {
 255         pstrcpy(devname, sizeof(devname), buf);
 256         for (type = 0; type < IF_COUNT && strcmp(buf, if_name[type]); type++)
 257             ;
 258         if (type == IF_COUNT) {
 259             error_report("unsupported bus type '%s'", buf);
 260             return NULL;
 261         }
 262     }
 263     max_devs = if_max_devs[type];
 264
 265     if (cyls || heads || secs) {
 266         if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
 267             error_report("invalid physical cyls number");
 268             return NULL;
 269         }
 270         if (heads < 1 || (type == IF_IDE && heads > 16)) {
 271             error_report("invalid physical heads number");
 272             return NULL;
 273         }
 274         if (secs < 1 || (type == IF_IDE && secs > 63)) {
 275             error_report("invalid physical secs number");
 276             return NULL;
 277         }
 278     }
 279
 280     if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
 281         if (!cyls) {
 282             error_report("'%s' trans must be used with cyls,heads and secs",
 283                          buf);
 284             return NULL;
 285         }
 286         if (!strcmp(buf, "none"))
 287             translation = BIOS_ATA_TRANSLATION_NONE;
 288         else if (!strcmp(buf, "lba"))
 289             translation = BIOS_ATA_TRANSLATION_LBA;
 290         else if (!strcmp(buf, "auto"))
 291             translation = BIOS_ATA_TRANSLATION_AUTO;
 292         else {
 293             error_report("'%s' invalid translation type", buf);
 294             return NULL;
 295         }
 296     }
 297
 298     if ((buf = qemu_opt_get(opts, "media")) != NULL) {
 299         if (!strcmp(buf, "disk")) {
 300             media = MEDIA_DISK;
 301         } else if (!strcmp(buf, "cdrom")) {
 302             if (cyls || secs || heads) {
 303                 error_report("'%s' invalid physical CHS format", buf);
 304                 return NULL;
 305             }
 306             media = MEDIA_CDROM;
 307         } else {
 308             error_report("'%s' invalid media", buf);
 309             return NULL;
 310         }
 311     }
 312
 313     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
 314         if (!strcmp(buf, "off") || !strcmp(buf, "none")) {
 315             bdrv_flags |= BDRV_O_NOCACHE;
 316         } else if (!strcmp(buf, "writeback")) {
 317             bdrv_flags |= BDRV_O_CACHE_WB;
 318         } else if (!strcmp(buf, "unsafe")) {
 319             bdrv_flags |= BDRV_O_CACHE_WB;
 320             bdrv_flags |= BDRV_O_NO_FLUSH;
 321         } else if (!strcmp(buf, "writethrough")) {
 322             /* this is the default */
 323         } else {
 324            error_report("invalid cache option");
 325            return NULL;
 326         }
 327     }
 328
 329 #ifdef CONFIG_LINUX_AIO
 330     if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
 331         if (!strcmp(buf, "native")) {
 332             bdrv_flags |= BDRV_O_NATIVE_AIO;
 333         } else if (!strcmp(buf, "threads")) {
 334             /* this is the default */
 335         } else {
 336            error_report("invalid aio option");
 337            return NULL;
 338         }
 339     }
 340 #endif
 341
 342     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
 343        if (strcmp(buf, "?") == 0) {
 344            error_printf("Supported formats:");
 345            bdrv_iterate_format(bdrv_format_print, NULL);
 346            error_printf("\n");
 347            return NULL;
 348         }
 349         drv = bdrv_find_whitelisted_format(buf);
 350         if (!drv) {
 351             error_report("'%s' invalid format", buf);
 352             return NULL;
 353         }
 354     }
 355
 356     on_write_error = BLOCK_ERR_STOP_ENOSPC;
 357     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
 358         if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
 359             error_report("werror is not supported by this bus type");
 360             return NULL;
 361         }
 362
 363         on_write_error = parse_block_error_action(buf, 0);
 364         if (on_write_error < 0) {
 365             return NULL;
 366         }
 367     }
 368
 369     on_read_error = BLOCK_ERR_REPORT;
 370     if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
 371         if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
 372             error_report("rerror is not supported by this bus type");
 373             return NULL;
 374         }
 375
 376         on_read_error = parse_block_error_action(buf, 1);
 377         if (on_read_error < 0) {
 378             return NULL;
 379         }
 380     }
 381
 382     if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
 383         if (type != IF_VIRTIO) {
 384             error_report("addr is not supported by this bus type");
 385             return NULL;
 386         }
 387     }
 388
 389     /* compute bus and unit according index */
 390
 391     if (index != -1) {
 392         if (bus_id != 0 || unit_id != -1) {
 393             error_report("index cannot be used with bus and unit");
 394             return NULL;
 395         }
 396         bus_id = drive_index_to_bus_id(type, index);
 397         unit_id = drive_index_to_unit_id(type, index);
 398     }
 399
 400     /* if user doesn't specify a unit_id,
 401      * try to find the first free
 402      */
 403
 404     if (unit_id == -1) {
 405        unit_id = 0;
 406        while (drive_get(type, bus_id, unit_id) != NULL) {
 407            unit_id++;
 408            if (max_devs && unit_id >= max_devs) {
 409                unit_id -= max_devs;
 410                bus_id++;
 411            }
 412        }
 413     }
 414
 415     /* check unit id */
 416
 417     if (max_devs && unit_id >= max_devs) {
 418         error_report("unit %d too big (max is %d)",
 419                      unit_id, max_devs - 1);
 420         return NULL;
 421     }
 422
 423     /*
 424      * catch multiple definitions
 425      */
 426
 427     if (drive_get(type, bus_id, unit_id) != NULL) {
 428         error_report("drive with bus=%d, unit=%d (index=%d) exists",
 429                      bus_id, unit_id, index);
 430         return NULL;
 431     }
 432
 433     /* init */
 434
 435     dinfo = qemu_mallocz(sizeof(*dinfo));
 436     if ((buf = qemu_opts_id(opts)) != NULL) {
 437         dinfo->id = qemu_strdup(buf);
 438     } else {
 439         /* no id supplied -> create one */
 440         dinfo->id = qemu_mallocz(32);
 441         if (type == IF_IDE || type == IF_SCSI)
 442             mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
 443         if (max_devs)
 444             snprintf(dinfo->id, 32, "%s%i%s%i",
 445                      devname, bus_id, mediastr, unit_id);
 446         else
 447             snprintf(dinfo->id, 32, "%s%s%i",
 448                      devname, mediastr, unit_id);
 449     }
 450     dinfo->bdrv = bdrv_new(dinfo->id);
 451     dinfo->devaddr = devaddr;
 452     dinfo->type = type;
 453     dinfo->bus = bus_id;
 454     dinfo->unit = unit_id;
 455     dinfo->opts = opts;
 456     if (serial)
 457         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
 458     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 459
 460     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 461
 462     switch(type) {
 463     case IF_IDE:
 464     case IF_SCSI:
 465     case IF_XEN:
 466     case IF_NONE:
 467         switch(media) {
 468         case MEDIA_DISK:
 469             if (cyls != 0) {
 470                 bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
 471                 bdrv_set_translation_hint(dinfo->bdrv, translation);
 472             }
 473             break;
 474         case MEDIA_CDROM:
 475             bdrv_set_type_hint(dinfo->bdrv, BDRV_TYPE_CDROM);
 476             break;
 477         }
 478         break;
 479     case IF_SD:
 480         /* FIXME: This isn't really a floppy, but it's a reasonable
 481            approximation.  */
 482     case IF_FLOPPY:
 483         bdrv_set_type_hint(dinfo->bdrv, BDRV_TYPE_FLOPPY);
 484         break;
 485     case IF_PFLASH:
 486     case IF_MTD:
 487         break;
 488     case IF_VIRTIO:
 489         /* add virtio block device */
 490         opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
 491         qemu_opt_set(opts, "driver", "virtio-blk-pci");
 492         qemu_opt_set(opts, "drive", dinfo->id);
 493         if (devaddr)
 494             qemu_opt_set(opts, "addr", devaddr);
 495         break;
 496     default:
 497         abort();
 498     }
 499     if (!file || !*file) {
 500         return dinfo;
 501     }
 502     if (snapshot) {
 503         /* always use cache=unsafe with snapshot */
 504         bdrv_flags &= ~BDRV_O_CACHE_MASK;
 505         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
 506     }
 507
 508     if (media == MEDIA_CDROM) {
 509         /* CDROM is fine for any interface, don't check.  */
 510         ro = 1;
 511     } else if (ro == 1) {
 512         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
 513             error_report("readonly not supported by this bus type");
 514             return NULL;
 515         }
 516     }
 517
 518     bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
 519
 520     ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
 521     if (ret < 0) {
 522         error_report("could not open disk image %s: %s",
 523                      file, strerror(-ret));
 524         return NULL;
 525     }
 526
 527     if (bdrv_key_required(dinfo->bdrv))
 528         autostart = 0;
 529     return dinfo;
 530 }
 531
 532 void do_commit(Monitor *mon, const QDict *qdict)
 533 {
 534     const char *device = qdict_get_str(qdict, "device");
 535     BlockDriverState *bs;
 536
 537     if (!strcmp(device, "all")) {
 538         bdrv_commit_all();
 539     } else {
 540         bs = bdrv_find(device);
 541         if (!bs) {
 542             qerror_report(QERR_DEVICE_NOT_FOUND, device);
 543             return;
 544         }
 545         bdrv_commit(bs);
 546     }
 547 }
 548
 549 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
 550 {
 551     const char *device = qdict_get_str(qdict, "device");
 552     const char *filename = qdict_get_try_str(qdict, "snapshot_file");
 553     const char *format = qdict_get_try_str(qdict, "format");
 554     BlockDriverState *bs;
 555     BlockDriver *drv, *proto_drv;
 556     int ret = 0;
 557     int flags;
 558
 559     if (!filename) {
 560         qerror_report(QERR_MISSING_PARAMETER, "snapshot_file");
 561         ret = -1;
 562         goto out;
 563     }
 564
 565     bs = bdrv_find(device);
 566     if (!bs) {
 567         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 568         ret = -1;
 569         goto out;
 570     }
 571
 572     if (!format) {
 573         format = "qcow2";
 574     }
 575
 576     drv = bdrv_find_format(format);
 577     if (!drv) {
 578         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 579         ret = -1;
 580         goto out;
 581     }
 582
 583     proto_drv = bdrv_find_protocol(filename);
 584     if (!proto_drv) {
 585         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 586         ret = -1;
 587         goto out;
 588     }
 589
 590     ret = bdrv_img_create(filename, format, bs->filename,
 591                           bs->drv->format_name, NULL, -1, bs->open_flags);
 592     if (ret) {
 593         goto out;
 594     }
 595
 596     qemu_aio_flush();
 597     bdrv_flush(bs);
 598
 599     flags = bs->open_flags;
 600     bdrv_close(bs);
 601     ret = bdrv_open(bs, filename, flags, drv);
 602     /*
 603      * If reopening the image file we just created fails, we really
 604      * are in trouble :(
 605      */
 606     if (ret != 0) {
 607         abort();
 608     }
 609 out:
 610     if (ret) {
 611         ret = -1;
 612     }
 613
 614     return ret;
 615 }
 616
 617 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 618 {
 619     if (!force) {
 620         if (!bdrv_is_removable(bs)) {
 621             qerror_report(QERR_DEVICE_NOT_REMOVABLE,
 622                            bdrv_get_device_name(bs));
 623             return -1;
 624         }
 625         if (bdrv_is_locked(bs)) {
 626             qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
 627             return -1;
 628         }
 629     }
 630     bdrv_close(bs);
 631     return 0;
 632 }
 633
 634 int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
 635 {
 636     BlockDriverState *bs;
 637     int force = qdict_get_try_bool(qdict, "force", 0);
 638     const char *filename = qdict_get_str(qdict, "device");
 639
 640     bs = bdrv_find(filename);
 641     if (!bs) {
 642         qerror_report(QERR_DEVICE_NOT_FOUND, filename);
 643         return -1;
 644     }
 645     return eject_device(mon, bs, force);
 646 }
 647
 648 int do_block_set_passwd(Monitor *mon, const QDict *qdict,
 649                         QObject **ret_data)
 650 {
 651     BlockDriverState *bs;
 652     int err;
 653
 654     bs = bdrv_find(qdict_get_str(qdict, "device"));
 655     if (!bs) {
 656         qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
 657         return -1;
 658     }
 659
 660     err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
 661     if (err == -EINVAL) {
 662         qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
 663         return -1;
 664     } else if (err < 0) {
 665         qerror_report(QERR_INVALID_PASSWORD);
 666         return -1;
 667     }
 668
 669     return 0;
 670 }
 671
 672 int do_change_block(Monitor *mon, const char *device,
 673                     const char *filename, const char *fmt)
 674 {
 675     BlockDriverState *bs;
 676     BlockDriver *drv = NULL;
 677     int bdrv_flags;
 678
 679     bs = bdrv_find(device);
 680     if (!bs) {
 681         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 682         return -1;
 683     }
 684     if (fmt) {
 685         drv = bdrv_find_whitelisted_format(fmt);
 686         if (!drv) {
 687             qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
 688             return -1;
 689         }
 690     }
 691     if (eject_device(mon, bs, 0) < 0) {
 692         return -1;
 693     }
 694     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
 695     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 696     if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
 697         qerror_report(QERR_OPEN_FILE_FAILED, filename);
 698         return -1;
 699     }
 700     return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
 701 }
 702
 703 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 704 {
 705     const char *id = qdict_get_str(qdict, "id");
 706     BlockDriverState *bs;
 707     BlockDriverState **ptr;
 708     Property *prop;
 709
 710     bs = bdrv_find(id);
 711     if (!bs) {
 712         qerror_report(QERR_DEVICE_NOT_FOUND, id);
 713         return -1;
 714     }
 715
 716     /* quiesce block driver; prevent further io */
 717     qemu_aio_flush();
 718     bdrv_flush(bs);
 719     bdrv_close(bs);
 720
 721     /* clean up guest state from pointing to host resource by
 722      * finding and removing DeviceState "drive" property */
 723     if (bs->peer) {
 724         for (prop = bs->peer->info->props; prop && prop->name; prop++) {
 725             if (prop->info->type == PROP_TYPE_DRIVE) {
 726                 ptr = qdev_get_prop_ptr(bs->peer, prop);
 727                 if (*ptr == bs) {
 728                     bdrv_detach(bs, bs->peer);
 729                     *ptr = NULL;
 730                     break;
 731                 }
 732             }
 733         }
 734     }
 735
 736     /* clean up host side */
 737     drive_uninit(drive_get_by_blockdev(bs));
 738
 739     return 0;
 740 }
 741
 742 /*
 743  * XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
 744  * existing QERR_ macro mess is cleaned up.  A good example for better
 745  * error reports can be found in the qemu-img resize code.
 746  */
 747 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
 748 {
 749     const char *device = qdict_get_str(qdict, "device");
 750     int64_t size = qdict_get_int(qdict, "size");
 751     BlockDriverState *bs;
 752
 753     bs = bdrv_find(device);
 754     if (!bs) {
 755         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 756         return -1;
 757     }
 758
 759     if (size < 0) {
 760         qerror_report(QERR_UNDEFINED_ERROR);
 761         return -1;
 762     }
 763
 764     if (bdrv_truncate(bs, size)) {
 765         qerror_report(QERR_UNDEFINED_ERROR);
 766         return -1;
 767     }
 768
 769     return 0;
 770 }