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 DriveInfo *extboot_drive = NULL;
  20
  21 static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
  22
  23 static const char *const if_name[IF_COUNT] = {
  24     [IF_NONE] = "none",
  25     [IF_IDE] = "ide",
  26     [IF_SCSI] = "scsi",
  27     [IF_FLOPPY] = "floppy",
  28     [IF_PFLASH] = "pflash",
  29     [IF_MTD] = "mtd",
  30     [IF_SD] = "sd",
  31     [IF_VIRTIO] = "virtio",
  32     [IF_XEN] = "xen",
  33 };
  34
  35 static const int if_max_devs[IF_COUNT] = {
  36     /*
  37      * Do not change these numbers!  They govern how drive option
  38      * index maps to unit and bus.  That mapping is ABI.
  39      *
  40      * All controllers used to imlement if=T drives need to support
  41      * if_max_devs[T] units, for any T with if_max_devs[T] != 0.
  42      * Otherwise, some index values map to "impossible" bus, unit
  43      * values.
  44      *
  45      * For instance, if you change [IF_SCSI] to 255, -drive
  46      * if=scsi,index=12 no longer means bus=1,unit=5, but
  47      * bus=0,unit=12.  With an lsi53c895a controller (7 units max),
  48      * the drive can't be set up.  Regression.
  49      */
  50     [IF_IDE] = 2,
  51     [IF_SCSI] = 7,
  52 };
  53
  54 /*
  55  * We automatically delete the drive when a device using it gets
  56  * unplugged.  Questionable feature, but we can't just drop it.
  57  * Device models call blockdev_mark_auto_del() to schedule the
  58  * automatic deletion, and generic qdev code calls blockdev_auto_del()
  59  * when deletion is actually safe.
  60  */
  61 void blockdev_mark_auto_del(BlockDriverState *bs)
  62 {
  63     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  64
  65     if (dinfo) {
  66         dinfo->auto_del = 1;
  67     }
  68 }
  69
  70 void blockdev_auto_del(BlockDriverState *bs)
  71 {
  72     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  73
  74     if (dinfo && dinfo->auto_del) {
  75         drive_put_ref(dinfo);
  76     }
  77 }
  78
  79 static int drive_index_to_bus_id(BlockInterfaceType type, int index)
  80 {
  81     int max_devs = if_max_devs[type];
  82     return max_devs ? index / max_devs : 0;
  83 }
  84
  85 static int drive_index_to_unit_id(BlockInterfaceType type, int index)
  86 {
  87     int max_devs = if_max_devs[type];
  88     return max_devs ? index % max_devs : index;
  89 }
  90
  91 QemuOpts *drive_def(const char *optstr)
  92 {
  93     return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
  94 }
  95
  96 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
  97                     const char *optstr)
  98 {
  99     QemuOpts *opts;
 100     char buf[32];
 101
 102     opts = drive_def(optstr);
 103     if (!opts) {
 104         return NULL;
 105     }
 106     if (type != IF_DEFAULT) {
 107         qemu_opt_set(opts, "if", if_name[type]);
 108     }
 109     if (index >= 0) {
 110         snprintf(buf, sizeof(buf), "%d", index);
 111         qemu_opt_set(opts, "index", buf);
 112     }
 113     if (file)
 114         qemu_opt_set(opts, "file", file);
 115     return opts;
 116 }
 117
 118 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
 119 {
 120     DriveInfo *dinfo;
 121
 122     /* seek interface, bus and unit */
 123
 124     QTAILQ_FOREACH(dinfo, &drives, next) {
 125         if (dinfo->type == type &&
 126             dinfo->bus == bus &&
 127             dinfo->unit == unit)
 128             return dinfo;
 129     }
 130
 131     return NULL;
 132 }
 133
 134 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)
 135 {
 136     return drive_get(type,
 137                      drive_index_to_bus_id(type, index),
 138                      drive_index_to_unit_id(type, index));
 139 }
 140
 141 int drive_get_max_bus(BlockInterfaceType type)
 142 {
 143     int max_bus;
 144     DriveInfo *dinfo;
 145
 146     max_bus = -1;
 147     QTAILQ_FOREACH(dinfo, &drives, next) {
 148         if(dinfo->type == type &&
 149            dinfo->bus > max_bus)
 150             max_bus = dinfo->bus;
 151     }
 152     return max_bus;
 153 }
 154
 155 /* Get a block device.  This should only be used for single-drive devices
 156    (e.g. SD/Floppy/MTD).  Multi-disk devices (scsi/ide) should use the
 157    appropriate bus.  */
 158 DriveInfo *drive_get_next(BlockInterfaceType type)
 159 {
 160     static int next_block_unit[IF_COUNT];
 161
 162     return drive_get(type, 0, next_block_unit[type]++);
 163 }
 164
 165 DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
 166 {
 167     DriveInfo *dinfo;
 168
 169     QTAILQ_FOREACH(dinfo, &drives, next) {
 170         if (dinfo->bdrv == bs) {
 171             return dinfo;
 172         }
 173     }
 174     return NULL;
 175 }
 176
 177 static void bdrv_format_print(void *opaque, const char *name)
 178 {
 179     error_printf(" %s", name);
 180 }
 181
 182 static void drive_uninit(DriveInfo *dinfo)
 183 {
 184     qemu_opts_del(dinfo->opts);
 185     bdrv_delete(dinfo->bdrv);
 186     g_free(dinfo->id);
 187     QTAILQ_REMOVE(&drives, dinfo, next);
 188     g_free(dinfo);
 189 }
 190
 191 void drive_put_ref(DriveInfo *dinfo)
 192 {
 193     assert(dinfo->refcount);
 194     if (--dinfo->refcount == 0) {
 195         drive_uninit(dinfo);
 196     }
 197 }
 198
 199 void drive_get_ref(DriveInfo *dinfo)
 200 {
 201     dinfo->refcount++;
 202 }
 203
 204 static int parse_block_error_action(const char *buf, int is_read)
 205 {
 206     if (!strcmp(buf, "ignore")) {
 207         return BLOCK_ERR_IGNORE;
 208     } else if (!is_read && !strcmp(buf, "enospc")) {
 209         return BLOCK_ERR_STOP_ENOSPC;
 210     } else if (!strcmp(buf, "stop")) {
 211         return BLOCK_ERR_STOP_ANY;
 212     } else if (!strcmp(buf, "report")) {
 213         return BLOCK_ERR_REPORT;
 214     } else {
 215         error_report("'%s' invalid %s error action",
 216                      buf, is_read ? "read" : "write");
 217         return -1;
 218     }
 219 }
 220
 221 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
 222 {
 223     const char *buf;
 224     const char *file = NULL;
 225     char devname[128];
 226     const char *serial;
 227     const char *mediastr = "";
 228     BlockInterfaceType type;
 229     enum { MEDIA_DISK, MEDIA_CDROM } media;
 230     int bus_id, unit_id;
 231     int cyls, heads, secs, translation;
 232     BlockDriver *drv = NULL;
 233     int max_devs;
 234     int index;
 235     int ro = 0;
 236     int bdrv_flags = 0;
 237     int on_read_error, on_write_error;
 238     const char *devaddr;
 239     DriveInfo *dinfo;
 240     int is_extboot = 0;
 241     int snapshot = 0;
 242     int ret;
 243
 244     translation = BIOS_ATA_TRANSLATION_AUTO;
 245     media = MEDIA_DISK;
 246
 247     /* extract parameters */
 248     bus_id  = qemu_opt_get_number(opts, "bus", 0);
 249     unit_id = qemu_opt_get_number(opts, "unit", -1);
 250     index   = qemu_opt_get_number(opts, "index", -1);
 251
 252     cyls  = qemu_opt_get_number(opts, "cyls", 0);
 253     heads = qemu_opt_get_number(opts, "heads", 0);
 254     secs  = qemu_opt_get_number(opts, "secs", 0);
 255
 256     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 257     ro = qemu_opt_get_bool(opts, "readonly", 0);
 258
 259     file = qemu_opt_get(opts, "file");
 260     serial = qemu_opt_get(opts, "serial");
 261
 262     if ((buf = qemu_opt_get(opts, "if")) != NULL) {
 263         pstrcpy(devname, sizeof(devname), buf);
 264         for (type = 0; type < IF_COUNT && strcmp(buf, if_name[type]); type++)
 265             ;
 266         if (type == IF_COUNT) {
 267             error_report("unsupported bus type '%s'", buf);
 268             return NULL;
 269         }
 270     } else {
 271         type = default_to_scsi ? IF_SCSI : IF_IDE;
 272         pstrcpy(devname, sizeof(devname), if_name[type]);
 273     }
 274
 275     max_devs = if_max_devs[type];
 276
 277     if (cyls || heads || secs) {
 278         if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
 279             error_report("invalid physical cyls number");
 280             return NULL;
 281         }
 282         if (heads < 1 || (type == IF_IDE && heads > 16)) {
 283             error_report("invalid physical heads number");
 284             return NULL;
 285         }
 286         if (secs < 1 || (type == IF_IDE && secs > 63)) {
 287             error_report("invalid physical secs number");
 288             return NULL;
 289         }
 290     }
 291
 292     if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
 293         if (!cyls) {
 294             error_report("'%s' trans must be used with cyls, heads and secs",
 295                          buf);
 296             return NULL;
 297         }
 298         if (!strcmp(buf, "none"))
 299             translation = BIOS_ATA_TRANSLATION_NONE;
 300         else if (!strcmp(buf, "lba"))
 301             translation = BIOS_ATA_TRANSLATION_LBA;
 302         else if (!strcmp(buf, "auto"))
 303             translation = BIOS_ATA_TRANSLATION_AUTO;
 304         else {
 305             error_report("'%s' invalid translation type", buf);
 306             return NULL;
 307         }
 308     }
 309
 310     if ((buf = qemu_opt_get(opts, "media")) != NULL) {
 311         if (!strcmp(buf, "disk")) {
 312             media = MEDIA_DISK;
 313         } else if (!strcmp(buf, "cdrom")) {
 314             if (cyls || secs || heads) {
 315                 error_report("CHS can't be set with media=%s", buf);
 316                 return NULL;
 317             }
 318             media = MEDIA_CDROM;
 319         } else {
 320             error_report("'%s' invalid media", buf);
 321             return NULL;
 322         }
 323     }
 324
 325     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
 326         if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {
 327             error_report("invalid cache option");
 328             return NULL;
 329         }
 330     }
 331
 332 #ifdef CONFIG_LINUX_AIO
 333     if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
 334         if (!strcmp(buf, "native")) {
 335             bdrv_flags |= BDRV_O_NATIVE_AIO;
 336         } else if (!strcmp(buf, "threads")) {
 337             /* this is the default */
 338         } else {
 339            error_report("invalid aio option");
 340            return NULL;
 341         }
 342     }
 343 #endif
 344
 345     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
 346        if (strcmp(buf, "?") == 0) {
 347            error_printf("Supported formats:");
 348            bdrv_iterate_format(bdrv_format_print, NULL);
 349            error_printf("\n");
 350            return NULL;
 351         }
 352         drv = bdrv_find_whitelisted_format(buf);
 353         if (!drv) {
 354             error_report("'%s' invalid format", buf);
 355             return NULL;
 356         }
 357     }
 358
 359     is_extboot = qemu_opt_get_bool(opts, "boot", 0);
 360     if (is_extboot && extboot_drive) {
 361         fprintf(stderr, "qemu: two bootable drives specified\n");
 362         return NULL;
 363     }
 364
 365     on_write_error = BLOCK_ERR_STOP_ENOSPC;
 366     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
 367         if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
 368             error_report("werror is not supported by this bus type");
 369             return NULL;
 370         }
 371
 372         on_write_error = parse_block_error_action(buf, 0);
 373         if (on_write_error < 0) {
 374             return NULL;
 375         }
 376     }
 377
 378     on_read_error = BLOCK_ERR_REPORT;
 379     if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
 380         if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
 381             error_report("rerror is not supported by this bus type");
 382             return NULL;
 383         }
 384
 385         on_read_error = parse_block_error_action(buf, 1);
 386         if (on_read_error < 0) {
 387             return NULL;
 388         }
 389     }
 390
 391     if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
 392         if (type != IF_VIRTIO) {
 393             error_report("addr is not supported by this bus type");
 394             return NULL;
 395         }
 396     }
 397
 398     /* compute bus and unit according index */
 399
 400     if (index != -1) {
 401         if (bus_id != 0 || unit_id != -1) {
 402             error_report("index cannot be used with bus and unit");
 403             return NULL;
 404         }
 405         bus_id = drive_index_to_bus_id(type, index);
 406         unit_id = drive_index_to_unit_id(type, index);
 407     }
 408
 409     /* if user doesn't specify a unit_id,
 410      * try to find the first free
 411      */
 412
 413     if (unit_id == -1) {
 414        unit_id = 0;
 415        while (drive_get(type, bus_id, unit_id) != NULL) {
 416            unit_id++;
 417            if (max_devs && unit_id >= max_devs) {
 418                unit_id -= max_devs;
 419                bus_id++;
 420            }
 421        }
 422     }
 423
 424     /* check unit id */
 425
 426     if (max_devs && unit_id >= max_devs) {
 427         error_report("unit %d too big (max is %d)",
 428                      unit_id, max_devs - 1);
 429         return NULL;
 430     }
 431
 432     /*
 433      * catch multiple definitions
 434      */
 435
 436     if (drive_get(type, bus_id, unit_id) != NULL) {
 437         error_report("drive with bus=%d, unit=%d (index=%d) exists",
 438                      bus_id, unit_id, index);
 439         return NULL;
 440     }
 441
 442     /* init */
 443
 444     dinfo = g_malloc0(sizeof(*dinfo));
 445     if ((buf = qemu_opts_id(opts)) != NULL) {
 446         dinfo->id = g_strdup(buf);
 447     } else {
 448         /* no id supplied -> create one */
 449         dinfo->id = g_malloc0(32);
 450         if (type == IF_IDE || type == IF_SCSI)
 451             mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
 452         if (max_devs)
 453             snprintf(dinfo->id, 32, "%s%i%s%i",
 454                      devname, bus_id, mediastr, unit_id);
 455         else
 456             snprintf(dinfo->id, 32, "%s%s%i",
 457                      devname, mediastr, unit_id);
 458     }
 459     dinfo->bdrv = bdrv_new(dinfo->id);
 460     dinfo->devaddr = devaddr;
 461     dinfo->type = type;
 462     dinfo->bus = bus_id;
 463     dinfo->unit = unit_id;
 464     dinfo->opts = opts;
 465     dinfo->refcount = 1;
 466     if (serial)
 467         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
 468     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 469
 470     if (is_extboot) {
 471         extboot_drive = dinfo;
 472     }
 473
 474     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 475
 476     switch(type) {
 477     case IF_IDE:
 478     case IF_SCSI:
 479     case IF_XEN:
 480     case IF_NONE:
 481         switch(media) {
 482         case MEDIA_DISK:
 483             if (cyls != 0) {
 484                 bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
 485                 bdrv_set_translation_hint(dinfo->bdrv, translation);
 486             }
 487             break;
 488         case MEDIA_CDROM:
 489             dinfo->media_cd = 1;
 490             break;
 491         }
 492         break;
 493     case IF_SD:
 494     case IF_FLOPPY:
 495     case IF_PFLASH:
 496     case IF_MTD:
 497         break;
 498     case IF_VIRTIO:
 499         /* add virtio block device */
 500         opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
 501         qemu_opt_set(opts, "driver", "virtio-blk");
 502         qemu_opt_set(opts, "drive", dinfo->id);
 503         if (devaddr)
 504             qemu_opt_set(opts, "addr", devaddr);
 505         break;
 506     default:
 507         abort();
 508     }
 509     if (!file || !*file) {
 510         return dinfo;
 511     }
 512     if (snapshot) {
 513         /* always use cache=unsafe with snapshot */
 514         bdrv_flags &= ~BDRV_O_CACHE_MASK;
 515         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
 516     }
 517
 518     if (media == MEDIA_CDROM) {
 519         /* CDROM is fine for any interface, don't check.  */
 520         ro = 1;
 521     } else if (ro == 1) {
 522         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
 523             error_report("readonly not supported by this bus type");
 524             goto err;
 525         }
 526     }
 527
 528     bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
 529
 530     ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
 531     if (ret < 0) {
 532         error_report("could not open disk image %s: %s",
 533                      file, strerror(-ret));
 534         goto err;
 535     }
 536
 537     if (bdrv_key_required(dinfo->bdrv))
 538         autostart = 0;
 539     return dinfo;
 540
 541 err:
 542     bdrv_delete(dinfo->bdrv);
 543     g_free(dinfo->id);
 544     QTAILQ_REMOVE(&drives, dinfo, next);
 545     g_free(dinfo);
 546     return NULL;
 547 }
 548
 549 void do_commit(Monitor *mon, const QDict *qdict)
 550 {
 551     const char *device = qdict_get_str(qdict, "device");
 552     BlockDriverState *bs;
 553
 554     if (!strcmp(device, "all")) {
 555         bdrv_commit_all();
 556     } else {
 557         bs = bdrv_find(device);
 558         if (!bs) {
 559             qerror_report(QERR_DEVICE_NOT_FOUND, device);
 560             return;
 561         }
 562         bdrv_commit(bs);
 563     }
 564 }
 565
 566 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
 567 {
 568     const char *device = qdict_get_str(qdict, "device");
 569     const char *filename = qdict_get_try_str(qdict, "snapshot-file");
 570     const char *format = qdict_get_try_str(qdict, "format");
 571     BlockDriverState *bs;
 572     BlockDriver *drv, *old_drv, *proto_drv;
 573     int ret = 0;
 574     int flags;
 575     char old_filename[1024];
 576
 577     if (!filename) {
 578         qerror_report(QERR_MISSING_PARAMETER, "snapshot-file");
 579         ret = -1;
 580         goto out;
 581     }
 582
 583     bs = bdrv_find(device);
 584     if (!bs) {
 585         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 586         ret = -1;
 587         goto out;
 588     }
 589
 590     pstrcpy(old_filename, sizeof(old_filename), bs->filename);
 591
 592     old_drv = bs->drv;
 593     flags = bs->open_flags;
 594
 595     if (!format) {
 596         format = "qcow2";
 597     }
 598
 599     drv = bdrv_find_format(format);
 600     if (!drv) {
 601         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 602         ret = -1;
 603         goto out;
 604     }
 605
 606     proto_drv = bdrv_find_protocol(filename);
 607     if (!proto_drv) {
 608         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 609         ret = -1;
 610         goto out;
 611     }
 612
 613     ret = bdrv_img_create(filename, format, bs->filename,
 614                           bs->drv->format_name, NULL, -1, flags);
 615     if (ret) {
 616         goto out;
 617     }
 618
 619     qemu_aio_flush();
 620     bdrv_flush(bs);
 621
 622     bdrv_close(bs);
 623     ret = bdrv_open(bs, filename, flags, drv);
 624     /*
 625      * If reopening the image file we just created fails, fall back
 626      * and try to re-open the original image. If that fails too, we
 627      * are in serious trouble.
 628      */
 629     if (ret != 0) {
 630         ret = bdrv_open(bs, old_filename, flags, old_drv);
 631         if (ret != 0) {
 632             qerror_report(QERR_OPEN_FILE_FAILED, old_filename);
 633         } else {
 634             qerror_report(QERR_OPEN_FILE_FAILED, filename);
 635         }
 636     }
 637 out:
 638     if (ret) {
 639         ret = -1;
 640     }
 641
 642     return ret;
 643 }
 644
 645 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 646 {
 647     if (!bdrv_dev_has_removable_media(bs)) {
 648         qerror_report(QERR_DEVICE_NOT_REMOVABLE, bdrv_get_device_name(bs));
 649         return -1;
 650     }
 651     if (!force && !bdrv_dev_is_tray_open(bs)
 652         && bdrv_dev_is_medium_locked(bs)) {
 653         qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
 654         return -1;
 655     }
 656     bdrv_close(bs);
 657     return 0;
 658 }
 659
 660 int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
 661 {
 662     BlockDriverState *bs;
 663     int force = qdict_get_try_bool(qdict, "force", 0);
 664     const char *filename = qdict_get_str(qdict, "device");
 665
 666     bs = bdrv_find(filename);
 667     if (!bs) {
 668         qerror_report(QERR_DEVICE_NOT_FOUND, filename);
 669         return -1;
 670     }
 671     return eject_device(mon, bs, force);
 672 }
 673
 674 int do_block_set_passwd(Monitor *mon, const QDict *qdict,
 675                         QObject **ret_data)
 676 {
 677     BlockDriverState *bs;
 678     int err;
 679
 680     bs = bdrv_find(qdict_get_str(qdict, "device"));
 681     if (!bs) {
 682         qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
 683         return -1;
 684     }
 685
 686     err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
 687     if (err == -EINVAL) {
 688         qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
 689         return -1;
 690     } else if (err < 0) {
 691         qerror_report(QERR_INVALID_PASSWORD);
 692         return -1;
 693     }
 694
 695     return 0;
 696 }
 697
 698 int do_change_block(Monitor *mon, const char *device,
 699                     const char *filename, const char *fmt)
 700 {
 701     BlockDriverState *bs;
 702     BlockDriver *drv = NULL;
 703     int bdrv_flags;
 704
 705     bs = bdrv_find(device);
 706     if (!bs) {
 707         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 708         return -1;
 709     }
 710     if (fmt) {
 711         drv = bdrv_find_whitelisted_format(fmt);
 712         if (!drv) {
 713             qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
 714             return -1;
 715         }
 716     }
 717     if (eject_device(mon, bs, 0) < 0) {
 718         return -1;
 719     }
 720     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
 721     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 722     if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
 723         qerror_report(QERR_OPEN_FILE_FAILED, filename);
 724         return -1;
 725     }
 726     return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
 727 }
 728
 729 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 730 {
 731     const char *id = qdict_get_str(qdict, "id");
 732     BlockDriverState *bs;
 733
 734     bs = bdrv_find(id);
 735     if (!bs) {
 736         qerror_report(QERR_DEVICE_NOT_FOUND, id);
 737         return -1;
 738     }
 739     if (bdrv_in_use(bs)) {
 740         qerror_report(QERR_DEVICE_IN_USE, id);
 741         return -1;
 742     }
 743
 744     /* quiesce block driver; prevent further io */
 745     qemu_aio_flush();
 746     bdrv_flush(bs);
 747     bdrv_close(bs);
 748
 749     /* if we have a device attached to this BlockDriverState
 750      * then we need to make the drive anonymous until the device
 751      * can be removed.  If this is a drive with no device backing
 752      * then we can just get rid of the block driver state right here.
 753      */
 754     if (bdrv_get_attached_dev(bs)) {
 755         bdrv_make_anon(bs);
 756     } else {
 757         drive_uninit(drive_get_by_blockdev(bs));
 758     }
 759
 760     return 0;
 761 }
 762
 763 /*
 764  * XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
 765  * existing QERR_ macro mess is cleaned up.  A good example for better
 766  * error reports can be found in the qemu-img resize code.
 767  */
 768 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
 769 {
 770     const char *device = qdict_get_str(qdict, "device");
 771     int64_t size = qdict_get_int(qdict, "size");
 772     BlockDriverState *bs;
 773
 774     bs = bdrv_find(device);
 775     if (!bs) {
 776         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 777         return -1;
 778     }
 779
 780     if (size < 0) {
 781         qerror_report(QERR_UNDEFINED_ERROR);
 782         return -1;
 783     }
 784
 785     if (bdrv_truncate(bs, size)) {
 786         qerror_report(QERR_UNDEFINED_ERROR);
 787         return -1;
 788     }
 789
 790     return 0;
 791 }