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 "block_int.h"
  18
  19 static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
  20
  21 static const char *const if_name[IF_COUNT] = {
  22     [IF_NONE] = "none",
  23     [IF_IDE] = "ide",
  24     [IF_SCSI] = "scsi",
  25     [IF_FLOPPY] = "floppy",
  26     [IF_PFLASH] = "pflash",
  27     [IF_MTD] = "mtd",
  28     [IF_SD] = "sd",
  29     [IF_VIRTIO] = "virtio",
  30     [IF_XEN] = "xen",
  31 };
  32
  33 static const int if_max_devs[IF_COUNT] = {
  34     /*
  35      * Do not change these numbers!  They govern how drive option
  36      * index maps to unit and bus.  That mapping is ABI.
  37      *
  38      * All controllers used to imlement if=T drives need to support
  39      * if_max_devs[T] units, for any T with if_max_devs[T] != 0.
  40      * Otherwise, some index values map to "impossible" bus, unit
  41      * values.
  42      *
  43      * For instance, if you change [IF_SCSI] to 255, -drive
  44      * if=scsi,index=12 no longer means bus=1,unit=5, but
  45      * bus=0,unit=12.  With an lsi53c895a controller (7 units max),
  46      * the drive can't be set up.  Regression.
  47      */
  48     [IF_IDE] = 2,
  49     [IF_SCSI] = 7,
  50 };
  51
  52 /*
  53  * We automatically delete the drive when a device using it gets
  54  * unplugged.  Questionable feature, but we can't just drop it.
  55  * Device models call blockdev_mark_auto_del() to schedule the
  56  * automatic deletion, and generic qdev code calls blockdev_auto_del()
  57  * when deletion is actually safe.
  58  */
  59 void blockdev_mark_auto_del(BlockDriverState *bs)
  60 {
  61     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  62
  63     if (dinfo) {
  64         dinfo->auto_del = 1;
  65     }
  66 }
  67
  68 void blockdev_auto_del(BlockDriverState *bs)
  69 {
  70     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  71
  72     if (dinfo && dinfo->auto_del) {
  73         drive_put_ref(dinfo);
  74     }
  75 }
  76
  77 static int drive_index_to_bus_id(BlockInterfaceType type, int index)
  78 {
  79     int max_devs = if_max_devs[type];
  80     return max_devs ? index / max_devs : 0;
  81 }
  82
  83 static int drive_index_to_unit_id(BlockInterfaceType type, int index)
  84 {
  85     int max_devs = if_max_devs[type];
  86     return max_devs ? index % max_devs : index;
  87 }
  88
  89 QemuOpts *drive_def(const char *optstr)
  90 {
  91     return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
  92 }
  93
  94 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
  95                     const char *optstr)
  96 {
  97     QemuOpts *opts;
  98     char buf[32];
  99
 100     opts = drive_def(optstr);
 101     if (!opts) {
 102         return NULL;
 103     }
 104     if (type != IF_DEFAULT) {
 105         qemu_opt_set(opts, "if", if_name[type]);
 106     }
 107     if (index >= 0) {
 108         snprintf(buf, sizeof(buf), "%d", index);
 109         qemu_opt_set(opts, "index", buf);
 110     }
 111     if (file)
 112         qemu_opt_set(opts, "file", file);
 113     return opts;
 114 }
 115
 116 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
 117 {
 118     DriveInfo *dinfo;
 119
 120     /* seek interface, bus and unit */
 121
 122     QTAILQ_FOREACH(dinfo, &drives, next) {
 123         if (dinfo->type == type &&
 124             dinfo->bus == bus &&
 125             dinfo->unit == unit)
 126             return dinfo;
 127     }
 128
 129     return NULL;
 130 }
 131
 132 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)
 133 {
 134     return drive_get(type,
 135                      drive_index_to_bus_id(type, index),
 136                      drive_index_to_unit_id(type, index));
 137 }
 138
 139 int drive_get_max_bus(BlockInterfaceType type)
 140 {
 141     int max_bus;
 142     DriveInfo *dinfo;
 143
 144     max_bus = -1;
 145     QTAILQ_FOREACH(dinfo, &drives, next) {
 146         if(dinfo->type == type &&
 147            dinfo->bus > max_bus)
 148             max_bus = dinfo->bus;
 149     }
 150     return max_bus;
 151 }
 152
 153 /* Get a block device.  This should only be used for single-drive devices
 154    (e.g. SD/Floppy/MTD).  Multi-disk devices (scsi/ide) should use the
 155    appropriate bus.  */
 156 DriveInfo *drive_get_next(BlockInterfaceType type)
 157 {
 158     static int next_block_unit[IF_COUNT];
 159
 160     return drive_get(type, 0, next_block_unit[type]++);
 161 }
 162
 163 DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
 164 {
 165     DriveInfo *dinfo;
 166
 167     QTAILQ_FOREACH(dinfo, &drives, next) {
 168         if (dinfo->bdrv == bs) {
 169             return dinfo;
 170         }
 171     }
 172     return NULL;
 173 }
 174
 175 static void bdrv_format_print(void *opaque, const char *name)
 176 {
 177     error_printf(" %s", name);
 178 }
 179
 180 static void drive_uninit(DriveInfo *dinfo)
 181 {
 182     qemu_opts_del(dinfo->opts);
 183     bdrv_delete(dinfo->bdrv);
 184     g_free(dinfo->id);
 185     QTAILQ_REMOVE(&drives, dinfo, next);
 186     g_free(dinfo);
 187 }
 188
 189 void drive_put_ref(DriveInfo *dinfo)
 190 {
 191     assert(dinfo->refcount);
 192     if (--dinfo->refcount == 0) {
 193         drive_uninit(dinfo);
 194     }
 195 }
 196
 197 void drive_get_ref(DriveInfo *dinfo)
 198 {
 199     dinfo->refcount++;
 200 }
 201
 202 static int parse_block_error_action(const char *buf, int is_read)
 203 {
 204     if (!strcmp(buf, "ignore")) {
 205         return BLOCK_ERR_IGNORE;
 206     } else if (!is_read && !strcmp(buf, "enospc")) {
 207         return BLOCK_ERR_STOP_ENOSPC;
 208     } else if (!strcmp(buf, "stop")) {
 209         return BLOCK_ERR_STOP_ANY;
 210     } else if (!strcmp(buf, "report")) {
 211         return BLOCK_ERR_REPORT;
 212     } else {
 213         error_report("'%s' invalid %s error action",
 214                      buf, is_read ? "read" : "write");
 215         return -1;
 216     }
 217 }
 218
 219 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
 220 {
 221     const char *buf;
 222     const char *file = NULL;
 223     char devname[128];
 224     const char *serial;
 225     const char *mediastr = "";
 226     BlockInterfaceType type;
 227     enum { MEDIA_DISK, MEDIA_CDROM } media;
 228     int bus_id, unit_id;
 229     int cyls, heads, secs, translation;
 230     BlockDriver *drv = NULL;
 231     int max_devs;
 232     int index;
 233     int ro = 0;
 234     int bdrv_flags = 0;
 235     int on_read_error, on_write_error;
 236     const char *devaddr;
 237     DriveInfo *dinfo;
 238     int snapshot = 0;
 239     int ret;
 240
 241     translation = BIOS_ATA_TRANSLATION_AUTO;
 242     media = MEDIA_DISK;
 243
 244     /* extract parameters */
 245     bus_id  = qemu_opt_get_number(opts, "bus", 0);
 246     unit_id = qemu_opt_get_number(opts, "unit", -1);
 247     index   = qemu_opt_get_number(opts, "index", -1);
 248
 249     cyls  = qemu_opt_get_number(opts, "cyls", 0);
 250     heads = qemu_opt_get_number(opts, "heads", 0);
 251     secs  = qemu_opt_get_number(opts, "secs", 0);
 252
 253     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 254     ro = qemu_opt_get_bool(opts, "readonly", 0);
 255
 256     file = qemu_opt_get(opts, "file");
 257     serial = qemu_opt_get(opts, "serial");
 258
 259     if ((buf = qemu_opt_get(opts, "if")) != NULL) {
 260         pstrcpy(devname, sizeof(devname), buf);
 261         for (type = 0; type < IF_COUNT && strcmp(buf, if_name[type]); type++)
 262             ;
 263         if (type == IF_COUNT) {
 264             error_report("unsupported bus type '%s'", buf);
 265             return NULL;
 266         }
 267     } else {
 268         type = default_to_scsi ? IF_SCSI : IF_IDE;
 269         pstrcpy(devname, sizeof(devname), if_name[type]);
 270     }
 271
 272     max_devs = if_max_devs[type];
 273
 274     if (cyls || heads || secs) {
 275         if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
 276             error_report("invalid physical cyls number");
 277             return NULL;
 278         }
 279         if (heads < 1 || (type == IF_IDE && heads > 16)) {
 280             error_report("invalid physical heads number");
 281             return NULL;
 282         }
 283         if (secs < 1 || (type == IF_IDE && secs > 63)) {
 284             error_report("invalid physical secs number");
 285             return NULL;
 286         }
 287     }
 288
 289     if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
 290         if (!cyls) {
 291             error_report("'%s' trans must be used with cyls, heads and secs",
 292                          buf);
 293             return NULL;
 294         }
 295         if (!strcmp(buf, "none"))
 296             translation = BIOS_ATA_TRANSLATION_NONE;
 297         else if (!strcmp(buf, "lba"))
 298             translation = BIOS_ATA_TRANSLATION_LBA;
 299         else if (!strcmp(buf, "auto"))
 300             translation = BIOS_ATA_TRANSLATION_AUTO;
 301         else {
 302             error_report("'%s' invalid translation type", buf);
 303             return NULL;
 304         }
 305     }
 306
 307     if ((buf = qemu_opt_get(opts, "media")) != NULL) {
 308         if (!strcmp(buf, "disk")) {
 309             media = MEDIA_DISK;
 310         } else if (!strcmp(buf, "cdrom")) {
 311             if (cyls || secs || heads) {
 312                 error_report("CHS can't be set with media=%s", buf);
 313                 return NULL;
 314             }
 315             media = MEDIA_CDROM;
 316         } else {
 317             error_report("'%s' invalid media", buf);
 318             return NULL;
 319         }
 320     }
 321
 322     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
 323         if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {
 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 = g_malloc0(sizeof(*dinfo));
 436     if ((buf = qemu_opts_id(opts)) != NULL) {
 437         dinfo->id = g_strdup(buf);
 438     } else {
 439         /* no id supplied -> create one */
 440         dinfo->id = g_malloc0(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     dinfo->refcount = 1;
 457     if (serial)
 458         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
 459     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 460
 461     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 462
 463     switch(type) {
 464     case IF_IDE:
 465     case IF_SCSI:
 466     case IF_XEN:
 467     case IF_NONE:
 468         switch(media) {
 469         case MEDIA_DISK:
 470             if (cyls != 0) {
 471                 bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
 472                 bdrv_set_translation_hint(dinfo->bdrv, translation);
 473             }
 474             break;
 475         case MEDIA_CDROM:
 476             dinfo->media_cd = 1;
 477             break;
 478         }
 479         break;
 480     case IF_SD:
 481     case IF_FLOPPY:
 482     case IF_PFLASH:
 483     case IF_MTD:
 484         break;
 485     case IF_VIRTIO:
 486         /* add virtio block device */
 487         opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
 488         qemu_opt_set(opts, "driver", "virtio-blk");
 489         qemu_opt_set(opts, "drive", dinfo->id);
 490         if (devaddr)
 491             qemu_opt_set(opts, "addr", devaddr);
 492         break;
 493     default:
 494         abort();
 495     }
 496     if (!file || !*file) {
 497         return dinfo;
 498     }
 499     if (snapshot) {
 500         /* always use cache=unsafe with snapshot */
 501         bdrv_flags &= ~BDRV_O_CACHE_MASK;
 502         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
 503     }
 504
 505     if (media == MEDIA_CDROM) {
 506         /* CDROM is fine for any interface, don't check.  */
 507         ro = 1;
 508     } else if (ro == 1) {
 509         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
 510             error_report("readonly not supported by this bus type");
 511             goto err;
 512         }
 513     }
 514
 515     bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
 516
 517     ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
 518     if (ret < 0) {
 519         error_report("could not open disk image %s: %s",
 520                      file, strerror(-ret));
 521         goto err;
 522     }
 523
 524     if (bdrv_key_required(dinfo->bdrv))
 525         autostart = 0;
 526     return dinfo;
 527
 528 err:
 529     bdrv_delete(dinfo->bdrv);
 530     g_free(dinfo->id);
 531     QTAILQ_REMOVE(&drives, dinfo, next);
 532     g_free(dinfo);
 533     return NULL;
 534 }
 535
 536 void do_commit(Monitor *mon, const QDict *qdict)
 537 {
 538     const char *device = qdict_get_str(qdict, "device");
 539     BlockDriverState *bs;
 540
 541     if (!strcmp(device, "all")) {
 542         bdrv_commit_all();
 543     } else {
 544         bs = bdrv_find(device);
 545         if (!bs) {
 546             qerror_report(QERR_DEVICE_NOT_FOUND, device);
 547             return;
 548         }
 549         bdrv_commit(bs);
 550     }
 551 }
 552
 553 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
 554 {
 555     const char *device = qdict_get_str(qdict, "device");
 556     const char *filename = qdict_get_try_str(qdict, "snapshot-file");
 557     const char *format = qdict_get_try_str(qdict, "format");
 558     BlockDriverState *bs;
 559     BlockDriver *drv, *old_drv, *proto_drv;
 560     int ret = 0;
 561     int flags;
 562     char old_filename[1024];
 563
 564     if (!filename) {
 565         qerror_report(QERR_MISSING_PARAMETER, "snapshot-file");
 566         ret = -1;
 567         goto out;
 568     }
 569
 570     bs = bdrv_find(device);
 571     if (!bs) {
 572         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 573         ret = -1;
 574         goto out;
 575     }
 576
 577     pstrcpy(old_filename, sizeof(old_filename), bs->filename);
 578
 579     old_drv = bs->drv;
 580     flags = bs->open_flags;
 581
 582     if (!format) {
 583         format = "qcow2";
 584     }
 585
 586     drv = bdrv_find_format(format);
 587     if (!drv) {
 588         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 589         ret = -1;
 590         goto out;
 591     }
 592
 593     proto_drv = bdrv_find_protocol(filename);
 594     if (!proto_drv) {
 595         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 596         ret = -1;
 597         goto out;
 598     }
 599
 600     ret = bdrv_img_create(filename, format, bs->filename,
 601                           bs->drv->format_name, NULL, -1, flags);
 602     if (ret) {
 603         goto out;
 604     }
 605
 606     qemu_aio_flush();
 607     bdrv_flush(bs);
 608
 609     bdrv_close(bs);
 610     ret = bdrv_open(bs, filename, flags, drv);
 611     /*
 612      * If reopening the image file we just created fails, fall back
 613      * and try to re-open the original image. If that fails too, we
 614      * are in serious trouble.
 615      */
 616     if (ret != 0) {
 617         ret = bdrv_open(bs, old_filename, flags, old_drv);
 618         if (ret != 0) {
 619             qerror_report(QERR_OPEN_FILE_FAILED, old_filename);
 620         } else {
 621             qerror_report(QERR_OPEN_FILE_FAILED, filename);
 622         }
 623     }
 624 out:
 625     if (ret) {
 626         ret = -1;
 627     }
 628
 629     return ret;
 630 }
 631
 632 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 633 {
 634     if (!bdrv_dev_has_removable_media(bs)) {
 635         qerror_report(QERR_DEVICE_NOT_REMOVABLE, bdrv_get_device_name(bs));
 636         return -1;
 637     }
 638     if (bdrv_dev_is_medium_locked(bs) && !bdrv_dev_is_tray_open(bs)) {
 639         bdrv_dev_eject_request(bs, force);
 640         if (!force) {
 641             qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
 642             return -1;
 643         }
 644     }
 645     bdrv_close(bs);
 646     return 0;
 647 }
 648
 649 int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
 650 {
 651     BlockDriverState *bs;
 652     int force = qdict_get_try_bool(qdict, "force", 0);
 653     const char *filename = qdict_get_str(qdict, "device");
 654
 655     bs = bdrv_find(filename);
 656     if (!bs) {
 657         qerror_report(QERR_DEVICE_NOT_FOUND, filename);
 658         return -1;
 659     }
 660     return eject_device(mon, bs, force);
 661 }
 662
 663 int do_block_set_passwd(Monitor *mon, const QDict *qdict,
 664                         QObject **ret_data)
 665 {
 666     BlockDriverState *bs;
 667     int err;
 668
 669     bs = bdrv_find(qdict_get_str(qdict, "device"));
 670     if (!bs) {
 671         qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
 672         return -1;
 673     }
 674
 675     err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
 676     if (err == -EINVAL) {
 677         qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
 678         return -1;
 679     } else if (err < 0) {
 680         qerror_report(QERR_INVALID_PASSWORD);
 681         return -1;
 682     }
 683
 684     return 0;
 685 }
 686
 687 int do_change_block(Monitor *mon, const char *device,
 688                     const char *filename, const char *fmt)
 689 {
 690     BlockDriverState *bs;
 691     BlockDriver *drv = NULL;
 692     int bdrv_flags;
 693
 694     bs = bdrv_find(device);
 695     if (!bs) {
 696         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 697         return -1;
 698     }
 699     if (fmt) {
 700         drv = bdrv_find_whitelisted_format(fmt);
 701         if (!drv) {
 702             qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
 703             return -1;
 704         }
 705     }
 706     if (eject_device(mon, bs, 0) < 0) {
 707         return -1;
 708     }
 709     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
 710     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 711     if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
 712         qerror_report(QERR_OPEN_FILE_FAILED, filename);
 713         return -1;
 714     }
 715     return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
 716 }
 717
 718 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 719 {
 720     const char *id = qdict_get_str(qdict, "id");
 721     BlockDriverState *bs;
 722
 723     bs = bdrv_find(id);
 724     if (!bs) {
 725         qerror_report(QERR_DEVICE_NOT_FOUND, id);
 726         return -1;
 727     }
 728     if (bdrv_in_use(bs)) {
 729         qerror_report(QERR_DEVICE_IN_USE, id);
 730         return -1;
 731     }
 732
 733     /* quiesce block driver; prevent further io */
 734     qemu_aio_flush();
 735     bdrv_flush(bs);
 736     bdrv_close(bs);
 737
 738     /* if we have a device attached to this BlockDriverState
 739      * then we need to make the drive anonymous until the device
 740      * can be removed.  If this is a drive with no device backing
 741      * then we can just get rid of the block driver state right here.
 742      */
 743     if (bdrv_get_attached_dev(bs)) {
 744         bdrv_make_anon(bs);
 745     } else {
 746         drive_uninit(drive_get_by_blockdev(bs));
 747     }
 748
 749     return 0;
 750 }
 751
 752 /*
 753  * XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
 754  * existing QERR_ macro mess is cleaned up.  A good example for better
 755  * error reports can be found in the qemu-img resize code.
 756  */
 757 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
 758 {
 759     const char *device = qdict_get_str(qdict, "device");
 760     int64_t size = qdict_get_int(qdict, "size");
 761     BlockDriverState *bs;
 762
 763     bs = bdrv_find(device);
 764     if (!bs) {
 765         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 766         return -1;
 767     }
 768
 769     if (size < 0) {
 770         qerror_report(QERR_UNDEFINED_ERROR);
 771         return -1;
 772     }
 773
 774     if (bdrv_truncate(bs, size)) {
 775         qerror_report(QERR_UNDEFINED_ERROR);
 776         return -1;
 777     }
 778
 779     return 0;
 780 }