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 DriveInfo *extboot_drive = NULL;
  21
  22 static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
  23
  24 static const char *const if_name[IF_COUNT] = {
  25     [IF_NONE] = "none",
  26     [IF_IDE] = "ide",
  27     [IF_SCSI] = "scsi",
  28     [IF_FLOPPY] = "floppy",
  29     [IF_PFLASH] = "pflash",
  30     [IF_MTD] = "mtd",
  31     [IF_SD] = "sd",
  32     [IF_VIRTIO] = "virtio",
  33     [IF_XEN] = "xen",
  34 };
  35
  36 static const int if_max_devs[IF_COUNT] = {
  37     /*
  38      * Do not change these numbers!  They govern how drive option
  39      * index maps to unit and bus.  That mapping is ABI.
  40      *
  41      * All controllers used to imlement if=T drives need to support
  42      * if_max_devs[T] units, for any T with if_max_devs[T] != 0.
  43      * Otherwise, some index values map to "impossible" bus, unit
  44      * values.
  45      *
  46      * For instance, if you change [IF_SCSI] to 255, -drive
  47      * if=scsi,index=12 no longer means bus=1,unit=5, but
  48      * bus=0,unit=12.  With an lsi53c895a controller (7 units max),
  49      * the drive can't be set up.  Regression.
  50      */
  51     [IF_IDE] = 2,
  52     [IF_SCSI] = 7,
  53 };
  54
  55 /*
  56  * We automatically delete the drive when a device using it gets
  57  * unplugged.  Questionable feature, but we can't just drop it.
  58  * Device models call blockdev_mark_auto_del() to schedule the
  59  * automatic deletion, and generic qdev code calls blockdev_auto_del()
  60  * when deletion is actually safe.
  61  */
  62 void blockdev_mark_auto_del(BlockDriverState *bs)
  63 {
  64     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  65
  66     if (dinfo) {
  67         dinfo->auto_del = 1;
  68     }
  69 }
  70
  71 void blockdev_auto_del(BlockDriverState *bs)
  72 {
  73     DriveInfo *dinfo = drive_get_by_blockdev(bs);
  74
  75     if (dinfo && dinfo->auto_del) {
  76         drive_put_ref(dinfo);
  77     }
  78 }
  79
  80 static int drive_index_to_bus_id(BlockInterfaceType type, int index)
  81 {
  82     int max_devs = if_max_devs[type];
  83     return max_devs ? index / max_devs : 0;
  84 }
  85
  86 static int drive_index_to_unit_id(BlockInterfaceType type, int index)
  87 {
  88     int max_devs = if_max_devs[type];
  89     return max_devs ? index % max_devs : index;
  90 }
  91
  92 QemuOpts *drive_def(const char *optstr)
  93 {
  94     return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
  95 }
  96
  97 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
  98                     const char *optstr)
  99 {
 100     QemuOpts *opts;
 101     char buf[32];
 102
 103     opts = drive_def(optstr);
 104     if (!opts) {
 105         return NULL;
 106     }
 107     if (type != IF_DEFAULT) {
 108         qemu_opt_set(opts, "if", if_name[type]);
 109     }
 110     if (index >= 0) {
 111         snprintf(buf, sizeof(buf), "%d", index);
 112         qemu_opt_set(opts, "index", buf);
 113     }
 114     if (file)
 115         qemu_opt_set(opts, "file", file);
 116     return opts;
 117 }
 118
 119 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
 120 {
 121     DriveInfo *dinfo;
 122
 123     /* seek interface, bus and unit */
 124
 125     QTAILQ_FOREACH(dinfo, &drives, next) {
 126         if (dinfo->type == type &&
 127             dinfo->bus == bus &&
 128             dinfo->unit == unit)
 129             return dinfo;
 130     }
 131
 132     return NULL;
 133 }
 134
 135 DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)
 136 {
 137     return drive_get(type,
 138                      drive_index_to_bus_id(type, index),
 139                      drive_index_to_unit_id(type, index));
 140 }
 141
 142 int drive_get_max_bus(BlockInterfaceType type)
 143 {
 144     int max_bus;
 145     DriveInfo *dinfo;
 146
 147     max_bus = -1;
 148     QTAILQ_FOREACH(dinfo, &drives, next) {
 149         if(dinfo->type == type &&
 150            dinfo->bus > max_bus)
 151             max_bus = dinfo->bus;
 152     }
 153     return max_bus;
 154 }
 155
 156 /* Get a block device.  This should only be used for single-drive devices
 157    (e.g. SD/Floppy/MTD).  Multi-disk devices (scsi/ide) should use the
 158    appropriate bus.  */
 159 DriveInfo *drive_get_next(BlockInterfaceType type)
 160 {
 161     static int next_block_unit[IF_COUNT];
 162
 163     return drive_get(type, 0, next_block_unit[type]++);
 164 }
 165
 166 DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
 167 {
 168     DriveInfo *dinfo;
 169
 170     QTAILQ_FOREACH(dinfo, &drives, next) {
 171         if (dinfo->bdrv == bs) {
 172             return dinfo;
 173         }
 174     }
 175     return NULL;
 176 }
 177
 178 static void bdrv_format_print(void *opaque, const char *name)
 179 {
 180     error_printf(" %s", name);
 181 }
 182
 183 static void drive_uninit(DriveInfo *dinfo)
 184 {
 185     qemu_opts_del(dinfo->opts);
 186     bdrv_delete(dinfo->bdrv);
 187     g_free(dinfo->id);
 188     QTAILQ_REMOVE(&drives, dinfo, next);
 189     g_free(dinfo);
 190 }
 191
 192 void drive_put_ref(DriveInfo *dinfo)
 193 {
 194     assert(dinfo->refcount);
 195     if (--dinfo->refcount == 0) {
 196         drive_uninit(dinfo);
 197     }
 198 }
 199
 200 void drive_get_ref(DriveInfo *dinfo)
 201 {
 202     dinfo->refcount++;
 203 }
 204
 205 static int parse_block_error_action(const char *buf, int is_read)
 206 {
 207     if (!strcmp(buf, "ignore")) {
 208         return BLOCK_ERR_IGNORE;
 209     } else if (!is_read && !strcmp(buf, "enospc")) {
 210         return BLOCK_ERR_STOP_ENOSPC;
 211     } else if (!strcmp(buf, "stop")) {
 212         return BLOCK_ERR_STOP_ANY;
 213     } else if (!strcmp(buf, "report")) {
 214         return BLOCK_ERR_REPORT;
 215     } else {
 216         error_report("'%s' invalid %s error action",
 217                      buf, is_read ? "read" : "write");
 218         return -1;
 219     }
 220 }
 221
 222 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
 223 {
 224     const char *buf;
 225     const char *file = NULL;
 226     char devname[128];
 227     const char *serial;
 228     const char *mediastr = "";
 229     BlockInterfaceType type;
 230     enum { MEDIA_DISK, MEDIA_CDROM } media;
 231     int bus_id, unit_id;
 232     int cyls, heads, secs, translation;
 233     BlockDriver *drv = NULL;
 234     int max_devs;
 235     int index;
 236     int ro = 0;
 237     int bdrv_flags = 0;
 238     int on_read_error, on_write_error;
 239     const char *devaddr;
 240     DriveInfo *dinfo;
 241     int is_extboot = 0;
 242     int snapshot = 0;
 243     int ret;
 244
 245     translation = BIOS_ATA_TRANSLATION_AUTO;
 246     media = MEDIA_DISK;
 247
 248     /* extract parameters */
 249     bus_id  = qemu_opt_get_number(opts, "bus", 0);
 250     unit_id = qemu_opt_get_number(opts, "unit", -1);
 251     index   = qemu_opt_get_number(opts, "index", -1);
 252
 253     cyls  = qemu_opt_get_number(opts, "cyls", 0);
 254     heads = qemu_opt_get_number(opts, "heads", 0);
 255     secs  = qemu_opt_get_number(opts, "secs", 0);
 256
 257     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 258     ro = qemu_opt_get_bool(opts, "readonly", 0);
 259
 260     file = qemu_opt_get(opts, "file");
 261     serial = qemu_opt_get(opts, "serial");
 262
 263     if ((buf = qemu_opt_get(opts, "if")) != NULL) {
 264         pstrcpy(devname, sizeof(devname), buf);
 265         for (type = 0; type < IF_COUNT && strcmp(buf, if_name[type]); type++)
 266             ;
 267         if (type == IF_COUNT) {
 268             error_report("unsupported bus type '%s'", buf);
 269             return NULL;
 270         }
 271     } else {
 272         type = default_to_scsi ? IF_SCSI : IF_IDE;
 273         pstrcpy(devname, sizeof(devname), if_name[type]);
 274     }
 275
 276     max_devs = if_max_devs[type];
 277
 278     if (cyls || heads || secs) {
 279         if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
 280             error_report("invalid physical cyls number");
 281             return NULL;
 282         }
 283         if (heads < 1 || (type == IF_IDE && heads > 16)) {
 284             error_report("invalid physical heads number");
 285             return NULL;
 286         }
 287         if (secs < 1 || (type == IF_IDE && secs > 63)) {
 288             error_report("invalid physical secs number");
 289             return NULL;
 290         }
 291     }
 292
 293     if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
 294         if (!cyls) {
 295             error_report("'%s' trans must be used with cyls, heads and secs",
 296                          buf);
 297             return NULL;
 298         }
 299         if (!strcmp(buf, "none"))
 300             translation = BIOS_ATA_TRANSLATION_NONE;
 301         else if (!strcmp(buf, "lba"))
 302             translation = BIOS_ATA_TRANSLATION_LBA;
 303         else if (!strcmp(buf, "auto"))
 304             translation = BIOS_ATA_TRANSLATION_AUTO;
 305         else {
 306             error_report("'%s' invalid translation type", buf);
 307             return NULL;
 308         }
 309     }
 310
 311     if ((buf = qemu_opt_get(opts, "media")) != NULL) {
 312         if (!strcmp(buf, "disk")) {
 313             media = MEDIA_DISK;
 314         } else if (!strcmp(buf, "cdrom")) {
 315             if (cyls || secs || heads) {
 316                 error_report("CHS can't be set with media=%s", buf);
 317                 return NULL;
 318             }
 319             media = MEDIA_CDROM;
 320         } else {
 321             error_report("'%s' invalid media", buf);
 322             return NULL;
 323         }
 324     }
 325
 326     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
 327         if (bdrv_parse_cache_flags(buf, &bdrv_flags) != 0) {
 328             error_report("invalid cache option");
 329             return NULL;
 330         }
 331     }
 332
 333 #ifdef CONFIG_LINUX_AIO
 334     if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
 335         if (!strcmp(buf, "native")) {
 336             bdrv_flags |= BDRV_O_NATIVE_AIO;
 337         } else if (!strcmp(buf, "threads")) {
 338             /* this is the default */
 339         } else {
 340            error_report("invalid aio option");
 341            return NULL;
 342         }
 343     }
 344 #endif
 345
 346     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
 347        if (strcmp(buf, "?") == 0) {
 348            error_printf("Supported formats:");
 349            bdrv_iterate_format(bdrv_format_print, NULL);
 350            error_printf("\n");
 351            return NULL;
 352         }
 353         drv = bdrv_find_whitelisted_format(buf);
 354         if (!drv) {
 355             error_report("'%s' invalid format", buf);
 356             return NULL;
 357         }
 358     }
 359
 360     is_extboot = qemu_opt_get_bool(opts, "boot", 0);
 361     if (is_extboot && extboot_drive) {
 362         fprintf(stderr, "qemu: two bootable drives specified\n");
 363         return NULL;
 364     }
 365
 366     on_write_error = BLOCK_ERR_STOP_ENOSPC;
 367     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
 368         if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
 369             error_report("werror is not supported by this bus type");
 370             return NULL;
 371         }
 372
 373         on_write_error = parse_block_error_action(buf, 0);
 374         if (on_write_error < 0) {
 375             return NULL;
 376         }
 377     }
 378
 379     on_read_error = BLOCK_ERR_REPORT;
 380     if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
 381         if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
 382             error_report("rerror is not supported by this bus type");
 383             return NULL;
 384         }
 385
 386         on_read_error = parse_block_error_action(buf, 1);
 387         if (on_read_error < 0) {
 388             return NULL;
 389         }
 390     }
 391
 392     if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
 393         if (type != IF_VIRTIO) {
 394             error_report("addr is not supported by this bus type");
 395             return NULL;
 396         }
 397     }
 398
 399     /* compute bus and unit according index */
 400
 401     if (index != -1) {
 402         if (bus_id != 0 || unit_id != -1) {
 403             error_report("index cannot be used with bus and unit");
 404             return NULL;
 405         }
 406         bus_id = drive_index_to_bus_id(type, index);
 407         unit_id = drive_index_to_unit_id(type, index);
 408     }
 409
 410     /* if user doesn't specify a unit_id,
 411      * try to find the first free
 412      */
 413
 414     if (unit_id == -1) {
 415        unit_id = 0;
 416        while (drive_get(type, bus_id, unit_id) != NULL) {
 417            unit_id++;
 418            if (max_devs && unit_id >= max_devs) {
 419                unit_id -= max_devs;
 420                bus_id++;
 421            }
 422        }
 423     }
 424
 425     /* check unit id */
 426
 427     if (max_devs && unit_id >= max_devs) {
 428         error_report("unit %d too big (max is %d)",
 429                      unit_id, max_devs - 1);
 430         return NULL;
 431     }
 432
 433     /*
 434      * catch multiple definitions
 435      */
 436
 437     if (drive_get(type, bus_id, unit_id) != NULL) {
 438         error_report("drive with bus=%d, unit=%d (index=%d) exists",
 439                      bus_id, unit_id, index);
 440         return NULL;
 441     }
 442
 443     /* init */
 444
 445     dinfo = g_malloc0(sizeof(*dinfo));
 446     if ((buf = qemu_opts_id(opts)) != NULL) {
 447         dinfo->id = g_strdup(buf);
 448     } else {
 449         /* no id supplied -> create one */
 450         dinfo->id = g_malloc0(32);
 451         if (type == IF_IDE || type == IF_SCSI)
 452             mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
 453         if (max_devs)
 454             snprintf(dinfo->id, 32, "%s%i%s%i",
 455                      devname, bus_id, mediastr, unit_id);
 456         else
 457             snprintf(dinfo->id, 32, "%s%s%i",
 458                      devname, mediastr, unit_id);
 459     }
 460     dinfo->bdrv = bdrv_new(dinfo->id);
 461     dinfo->devaddr = devaddr;
 462     dinfo->type = type;
 463     dinfo->bus = bus_id;
 464     dinfo->unit = unit_id;
 465     dinfo->opts = opts;
 466     dinfo->refcount = 1;
 467     if (serial)
 468         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
 469     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
 470
 471     if (is_extboot) {
 472         extboot_drive = dinfo;
 473     }
 474
 475     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 476
 477     switch(type) {
 478     case IF_IDE:
 479     case IF_SCSI:
 480     case IF_XEN:
 481     case IF_NONE:
 482         switch(media) {
 483         case MEDIA_DISK:
 484             if (cyls != 0) {
 485                 bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
 486                 bdrv_set_translation_hint(dinfo->bdrv, translation);
 487             }
 488             break;
 489         case MEDIA_CDROM:
 490             bdrv_set_removable(dinfo->bdrv, 1);
 491             dinfo->media_cd = 1;
 492             break;
 493         }
 494         break;
 495     case IF_SD:
 496         /* FIXME: This isn't really a floppy, but it's a reasonable
 497            approximation.  */
 498     case IF_FLOPPY:
 499         bdrv_set_removable(dinfo->bdrv, 1);
 500         break;
 501     case IF_PFLASH:
 502     case IF_MTD:
 503         break;
 504     case IF_VIRTIO:
 505         /* add virtio block device */
 506         opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
 507         qemu_opt_set(opts, "driver", "virtio-blk");
 508         qemu_opt_set(opts, "drive", dinfo->id);
 509         if (devaddr)
 510             qemu_opt_set(opts, "addr", devaddr);
 511         break;
 512     default:
 513         abort();
 514     }
 515     if (!file || !*file) {
 516         return dinfo;
 517     }
 518     if (snapshot) {
 519         /* always use cache=unsafe with snapshot */
 520         bdrv_flags &= ~BDRV_O_CACHE_MASK;
 521         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
 522     }
 523
 524     if (media == MEDIA_CDROM) {
 525         /* CDROM is fine for any interface, don't check.  */
 526         ro = 1;
 527     } else if (ro == 1) {
 528         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
 529             error_report("readonly not supported by this bus type");
 530             goto err;
 531         }
 532     }
 533
 534     bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
 535
 536     ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
 537     if (ret < 0) {
 538         error_report("could not open disk image %s: %s",
 539                      file, strerror(-ret));
 540         goto err;
 541     }
 542
 543     if (bdrv_key_required(dinfo->bdrv))
 544         autostart = 0;
 545     return dinfo;
 546
 547 err:
 548     bdrv_delete(dinfo->bdrv);
 549     g_free(dinfo->id);
 550     QTAILQ_REMOVE(&drives, dinfo, next);
 551     g_free(dinfo);
 552     return NULL;
 553 }
 554
 555 void do_commit(Monitor *mon, const QDict *qdict)
 556 {
 557     const char *device = qdict_get_str(qdict, "device");
 558     BlockDriverState *bs;
 559
 560     if (!strcmp(device, "all")) {
 561         bdrv_commit_all();
 562     } else {
 563         bs = bdrv_find(device);
 564         if (!bs) {
 565             qerror_report(QERR_DEVICE_NOT_FOUND, device);
 566             return;
 567         }
 568         bdrv_commit(bs);
 569     }
 570 }
 571
 572 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
 573 {
 574     const char *device = qdict_get_str(qdict, "device");
 575     const char *filename = qdict_get_try_str(qdict, "snapshot-file");
 576     const char *format = qdict_get_try_str(qdict, "format");
 577     BlockDriverState *bs;
 578     BlockDriver *drv, *old_drv, *proto_drv;
 579     int ret = 0;
 580     int flags;
 581     char old_filename[1024];
 582
 583     if (!filename) {
 584         qerror_report(QERR_MISSING_PARAMETER, "snapshot-file");
 585         ret = -1;
 586         goto out;
 587     }
 588
 589     bs = bdrv_find(device);
 590     if (!bs) {
 591         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 592         ret = -1;
 593         goto out;
 594     }
 595
 596     pstrcpy(old_filename, sizeof(old_filename), bs->filename);
 597
 598     old_drv = bs->drv;
 599     flags = bs->open_flags;
 600
 601     if (!format) {
 602         format = "qcow2";
 603     }
 604
 605     drv = bdrv_find_format(format);
 606     if (!drv) {
 607         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 608         ret = -1;
 609         goto out;
 610     }
 611
 612     proto_drv = bdrv_find_protocol(filename);
 613     if (!proto_drv) {
 614         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 615         ret = -1;
 616         goto out;
 617     }
 618
 619     ret = bdrv_img_create(filename, format, bs->filename,
 620                           bs->drv->format_name, NULL, -1, flags);
 621     if (ret) {
 622         goto out;
 623     }
 624
 625     qemu_aio_flush();
 626     bdrv_flush(bs);
 627
 628     bdrv_close(bs);
 629     ret = bdrv_open(bs, filename, flags, drv);
 630     /*
 631      * If reopening the image file we just created fails, fall back
 632      * and try to re-open the original image. If that fails too, we
 633      * are in serious trouble.
 634      */
 635     if (ret != 0) {
 636         ret = bdrv_open(bs, old_filename, flags, old_drv);
 637         if (ret != 0) {
 638             qerror_report(QERR_OPEN_FILE_FAILED, old_filename);
 639         } else {
 640             qerror_report(QERR_OPEN_FILE_FAILED, filename);
 641         }
 642     }
 643 out:
 644     if (ret) {
 645         ret = -1;
 646     }
 647
 648     return ret;
 649 }
 650
 651 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 652 {
 653     if (!bdrv_is_removable(bs)) {
 654         qerror_report(QERR_DEVICE_NOT_REMOVABLE, bdrv_get_device_name(bs));
 655         return -1;
 656     }
 657     if (!force && bdrv_is_locked(bs)) {
 658         qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
 659         return -1;
 660     }
 661     bdrv_close(bs);
 662     return 0;
 663 }
 664
 665 int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
 666 {
 667     BlockDriverState *bs;
 668     int force = qdict_get_try_bool(qdict, "force", 0);
 669     const char *filename = qdict_get_str(qdict, "device");
 670
 671     bs = bdrv_find(filename);
 672     if (!bs) {
 673         qerror_report(QERR_DEVICE_NOT_FOUND, filename);
 674         return -1;
 675     }
 676     return eject_device(mon, bs, force);
 677 }
 678
 679 int do_block_set_passwd(Monitor *mon, const QDict *qdict,
 680                         QObject **ret_data)
 681 {
 682     BlockDriverState *bs;
 683     int err;
 684
 685     bs = bdrv_find(qdict_get_str(qdict, "device"));
 686     if (!bs) {
 687         qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
 688         return -1;
 689     }
 690
 691     err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
 692     if (err == -EINVAL) {
 693         qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
 694         return -1;
 695     } else if (err < 0) {
 696         qerror_report(QERR_INVALID_PASSWORD);
 697         return -1;
 698     }
 699
 700     return 0;
 701 }
 702
 703 int do_change_block(Monitor *mon, const char *device,
 704                     const char *filename, const char *fmt)
 705 {
 706     BlockDriverState *bs;
 707     BlockDriver *drv = NULL;
 708     int bdrv_flags;
 709
 710     bs = bdrv_find(device);
 711     if (!bs) {
 712         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 713         return -1;
 714     }
 715     if (fmt) {
 716         drv = bdrv_find_whitelisted_format(fmt);
 717         if (!drv) {
 718             qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
 719             return -1;
 720         }
 721     }
 722     if (eject_device(mon, bs, 0) < 0) {
 723         return -1;
 724     }
 725     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
 726     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 727     if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
 728         qerror_report(QERR_OPEN_FILE_FAILED, filename);
 729         return -1;
 730     }
 731     return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
 732 }
 733
 734 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 735 {
 736     const char *id = qdict_get_str(qdict, "id");
 737     BlockDriverState *bs;
 738
 739     bs = bdrv_find(id);
 740     if (!bs) {
 741         qerror_report(QERR_DEVICE_NOT_FOUND, id);
 742         return -1;
 743     }
 744     if (bdrv_in_use(bs)) {
 745         qerror_report(QERR_DEVICE_IN_USE, id);
 746         return -1;
 747     }
 748
 749     /* quiesce block driver; prevent further io */
 750     qemu_aio_flush();
 751     bdrv_flush(bs);
 752     bdrv_close(bs);
 753
 754     /* if we have a device associated with this BlockDriverState (bs->peer)
 755      * then we need to make the drive anonymous until the device
 756      * can be removed.  If this is a drive with no device backing
 757      * then we can just get rid of the block driver state right here.
 758      */
 759     if (bs->peer) {
 760         bdrv_make_anon(bs);
 761     } else {
 762         drive_uninit(drive_get_by_blockdev(bs));
 763     }
 764
 765     return 0;
 766 }
 767
 768 /*
 769  * XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
 770  * existing QERR_ macro mess is cleaned up.  A good example for better
 771  * error reports can be found in the qemu-img resize code.
 772  */
 773 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
 774 {
 775     const char *device = qdict_get_str(qdict, "device");
 776     int64_t size = qdict_get_int(qdict, "size");
 777     BlockDriverState *bs;
 778
 779     bs = bdrv_find(device);
 780     if (!bs) {
 781         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 782         return -1;
 783     }
 784
 785     if (size < 0) {
 786         qerror_report(QERR_UNDEFINED_ERROR);
 787         return -1;
 788     }
 789
 790     if (bdrv_truncate(bs, size)) {
 791         qerror_report(QERR_UNDEFINED_ERROR);
 792         return -1;
 793     }
 794
 795     return 0;
 796 }