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_put_ref(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 static void drive_uninit(DriveInfo *dinfo)
 182 {
 183     qemu_opts_del(dinfo->opts);
 184     bdrv_delete(dinfo->bdrv);
 185     qemu_free(dinfo->id);
 186     QTAILQ_REMOVE(&drives, dinfo, next);
 187     qemu_free(dinfo);
 188 }
 189
 190 void drive_put_ref(DriveInfo *dinfo)
 191 {
 192     assert(dinfo->refcount);
 193     if (--dinfo->refcount == 0) {
 194         drive_uninit(dinfo);
 195     }
 196 }
 197
 198 void drive_get_ref(DriveInfo *dinfo)
 199 {
 200     dinfo->refcount++;
 201 }
 202
 203 static int parse_block_error_action(const char *buf, int is_read)
 204 {
 205     if (!strcmp(buf, "ignore")) {
 206         return BLOCK_ERR_IGNORE;
 207     } else if (!is_read && !strcmp(buf, "enospc")) {
 208         return BLOCK_ERR_STOP_ENOSPC;
 209     } else if (!strcmp(buf, "stop")) {
 210         return BLOCK_ERR_STOP_ANY;
 211     } else if (!strcmp(buf, "report")) {
 212         return BLOCK_ERR_REPORT;
 213     } else {
 214         error_report("'%s' invalid %s error action",
 215                      buf, is_read ? "read" : "write");
 216         return -1;
 217     }
 218 }
 219
 220 DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
 221 {
 222     const char *buf;
 223     const char *file = NULL;
 224     char devname[128];
 225     const char *serial;
 226     const char *mediastr = "";
 227     BlockInterfaceType type;
 228     enum { MEDIA_DISK, MEDIA_CDROM } media;
 229     int bus_id, unit_id;
 230     int cyls, heads, secs, translation;
 231     BlockDriver *drv = NULL;
 232     int max_devs;
 233     int index;
 234     int ro = 0;
 235     int bdrv_flags = 0;
 236     int on_read_error, on_write_error;
 237     const char *devaddr;
 238     DriveInfo *dinfo;
 239     int snapshot = 0;
 240     int ret;
 241
 242     translation = BIOS_ATA_TRANSLATION_AUTO;
 243     media = MEDIA_DISK;
 244
 245     /* extract parameters */
 246     bus_id  = qemu_opt_get_number(opts, "bus", 0);
 247     unit_id = qemu_opt_get_number(opts, "unit", -1);
 248     index   = qemu_opt_get_number(opts, "index", -1);
 249
 250     cyls  = qemu_opt_get_number(opts, "cyls", 0);
 251     heads = qemu_opt_get_number(opts, "heads", 0);
 252     secs  = qemu_opt_get_number(opts, "secs", 0);
 253
 254     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
 255     ro = qemu_opt_get_bool(opts, "readonly", 0);
 256
 257     file = qemu_opt_get(opts, "file");
 258     serial = qemu_opt_get(opts, "serial");
 259
 260     if ((buf = qemu_opt_get(opts, "if")) != NULL) {
 261         pstrcpy(devname, sizeof(devname), buf);
 262         for (type = 0; type < IF_COUNT && strcmp(buf, if_name[type]); type++)
 263             ;
 264         if (type == IF_COUNT) {
 265             error_report("unsupported bus type '%s'", buf);
 266             return NULL;
 267         }
 268     } else {
 269         type = default_to_scsi ? IF_SCSI : IF_IDE;
 270         pstrcpy(devname, sizeof(devname), if_name[type]);
 271     }
 272
 273     max_devs = if_max_devs[type];
 274
 275     if (cyls || heads || secs) {
 276         if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
 277             error_report("invalid physical cyls number");
 278             return NULL;
 279         }
 280         if (heads < 1 || (type == IF_IDE && heads > 16)) {
 281             error_report("invalid physical heads number");
 282             return NULL;
 283         }
 284         if (secs < 1 || (type == IF_IDE && secs > 63)) {
 285             error_report("invalid physical secs number");
 286             return NULL;
 287         }
 288     }
 289
 290     if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
 291         if (!cyls) {
 292             error_report("'%s' trans must be used with cyls, heads and secs",
 293                          buf);
 294             return NULL;
 295         }
 296         if (!strcmp(buf, "none"))
 297             translation = BIOS_ATA_TRANSLATION_NONE;
 298         else if (!strcmp(buf, "lba"))
 299             translation = BIOS_ATA_TRANSLATION_LBA;
 300         else if (!strcmp(buf, "auto"))
 301             translation = BIOS_ATA_TRANSLATION_AUTO;
 302         else {
 303             error_report("'%s' invalid translation type", buf);
 304             return NULL;
 305         }
 306     }
 307
 308     if ((buf = qemu_opt_get(opts, "media")) != NULL) {
 309         if (!strcmp(buf, "disk")) {
 310             media = MEDIA_DISK;
 311         } else if (!strcmp(buf, "cdrom")) {
 312             if (cyls || secs || heads) {
 313                 error_report("CHS can't be set with media=%s", buf);
 314                 return NULL;
 315             }
 316             media = MEDIA_CDROM;
 317         } else {
 318             error_report("'%s' invalid media", buf);
 319             return NULL;
 320         }
 321     }
 322
 323     if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
 324         if (!strcmp(buf, "off") || !strcmp(buf, "none")) {
 325             bdrv_flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
 326         } else if (!strcmp(buf, "writeback")) {
 327             bdrv_flags |= BDRV_O_CACHE_WB;
 328         } else if (!strcmp(buf, "unsafe")) {
 329             bdrv_flags |= BDRV_O_CACHE_WB;
 330             bdrv_flags |= BDRV_O_NO_FLUSH;
 331         } else if (!strcmp(buf, "writethrough")) {
 332             /* this is the default */
 333         } else {
 334            error_report("invalid cache option");
 335            return NULL;
 336         }
 337     }
 338
 339 #ifdef CONFIG_LINUX_AIO
 340     if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
 341         if (!strcmp(buf, "native")) {
 342             bdrv_flags |= BDRV_O_NATIVE_AIO;
 343         } else if (!strcmp(buf, "threads")) {
 344             /* this is the default */
 345         } else {
 346            error_report("invalid aio option");
 347            return NULL;
 348         }
 349     }
 350 #endif
 351
 352     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
 353        if (strcmp(buf, "?") == 0) {
 354            error_printf("Supported formats:");
 355            bdrv_iterate_format(bdrv_format_print, NULL);
 356            error_printf("\n");
 357            return NULL;
 358         }
 359         drv = bdrv_find_whitelisted_format(buf);
 360         if (!drv) {
 361             error_report("'%s' invalid format", buf);
 362             return NULL;
 363         }
 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 = qemu_mallocz(sizeof(*dinfo));
 446     if ((buf = qemu_opts_id(opts)) != NULL) {
 447         dinfo->id = qemu_strdup(buf);
 448     } else {
 449         /* no id supplied -> create one */
 450         dinfo->id = qemu_mallocz(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     bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
 472
 473     switch(type) {
 474     case IF_IDE:
 475     case IF_SCSI:
 476     case IF_XEN:
 477     case IF_NONE:
 478         switch(media) {
 479         case MEDIA_DISK:
 480             if (cyls != 0) {
 481                 bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
 482                 bdrv_set_translation_hint(dinfo->bdrv, translation);
 483             }
 484             break;
 485         case MEDIA_CDROM:
 486             bdrv_set_removable(dinfo->bdrv, 1);
 487             dinfo->media_cd = 1;
 488             break;
 489         }
 490         break;
 491     case IF_SD:
 492         /* FIXME: This isn't really a floppy, but it's a reasonable
 493            approximation.  */
 494     case IF_FLOPPY:
 495         bdrv_set_removable(dinfo->bdrv, 1);
 496         break;
 497     case IF_PFLASH:
 498     case IF_MTD:
 499         break;
 500     case IF_VIRTIO:
 501         /* add virtio block device */
 502         opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
 503         qemu_opt_set(opts, "driver", "virtio-blk");
 504         qemu_opt_set(opts, "drive", dinfo->id);
 505         if (devaddr)
 506             qemu_opt_set(opts, "addr", devaddr);
 507         break;
 508     default:
 509         abort();
 510     }
 511     if (!file || !*file) {
 512         return dinfo;
 513     }
 514     if (snapshot) {
 515         /* always use cache=unsafe with snapshot */
 516         bdrv_flags &= ~BDRV_O_CACHE_MASK;
 517         bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
 518     }
 519
 520     if (media == MEDIA_CDROM) {
 521         /* CDROM is fine for any interface, don't check.  */
 522         ro = 1;
 523     } else if (ro == 1) {
 524         if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
 525             error_report("readonly not supported by this bus type");
 526             goto err;
 527         }
 528     }
 529
 530     bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
 531
 532     ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
 533     if (ret < 0) {
 534         error_report("could not open disk image %s: %s",
 535                      file, strerror(-ret));
 536         goto err;
 537     }
 538
 539     if (bdrv_key_required(dinfo->bdrv))
 540         autostart = 0;
 541     return dinfo;
 542
 543 err:
 544     bdrv_delete(dinfo->bdrv);
 545     qemu_free(dinfo->id);
 546     QTAILQ_REMOVE(&drives, dinfo, next);
 547     qemu_free(dinfo);
 548     return NULL;
 549 }
 550
 551 void do_commit(Monitor *mon, const QDict *qdict)
 552 {
 553     const char *device = qdict_get_str(qdict, "device");
 554     BlockDriverState *bs;
 555
 556     if (!strcmp(device, "all")) {
 557         bdrv_commit_all();
 558     } else {
 559         bs = bdrv_find(device);
 560         if (!bs) {
 561             qerror_report(QERR_DEVICE_NOT_FOUND, device);
 562             return;
 563         }
 564         bdrv_commit(bs);
 565     }
 566 }
 567
 568 int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
 569 {
 570     const char *device = qdict_get_str(qdict, "device");
 571     const char *filename = qdict_get_try_str(qdict, "snapshot-file");
 572     const char *format = qdict_get_try_str(qdict, "format");
 573     BlockDriverState *bs;
 574     BlockDriver *drv, *old_drv, *proto_drv;
 575     int ret = 0;
 576     int flags;
 577     char old_filename[1024];
 578
 579     if (!filename) {
 580         qerror_report(QERR_MISSING_PARAMETER, "snapshot-file");
 581         ret = -1;
 582         goto out;
 583     }
 584
 585     bs = bdrv_find(device);
 586     if (!bs) {
 587         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 588         ret = -1;
 589         goto out;
 590     }
 591
 592     pstrcpy(old_filename, sizeof(old_filename), bs->filename);
 593
 594     old_drv = bs->drv;
 595     flags = bs->open_flags;
 596
 597     if (!format) {
 598         format = "qcow2";
 599     }
 600
 601     drv = bdrv_find_format(format);
 602     if (!drv) {
 603         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 604         ret = -1;
 605         goto out;
 606     }
 607
 608     proto_drv = bdrv_find_protocol(filename);
 609     if (!proto_drv) {
 610         qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
 611         ret = -1;
 612         goto out;
 613     }
 614
 615     ret = bdrv_img_create(filename, format, bs->filename,
 616                           bs->drv->format_name, NULL, -1, flags);
 617     if (ret) {
 618         goto out;
 619     }
 620
 621     qemu_aio_flush();
 622     bdrv_flush(bs);
 623
 624     bdrv_close(bs);
 625     ret = bdrv_open(bs, filename, flags, drv);
 626     /*
 627      * If reopening the image file we just created fails, fall back
 628      * and try to re-open the original image. If that fails too, we
 629      * are in serious trouble.
 630      */
 631     if (ret != 0) {
 632         ret = bdrv_open(bs, old_filename, flags, old_drv);
 633         if (ret != 0) {
 634             qerror_report(QERR_OPEN_FILE_FAILED, old_filename);
 635         } else {
 636             qerror_report(QERR_OPEN_FILE_FAILED, filename);
 637         }
 638     }
 639 out:
 640     if (ret) {
 641         ret = -1;
 642     }
 643
 644     return ret;
 645 }
 646
 647 static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
 648 {
 649     if (!bdrv_is_removable(bs)) {
 650         qerror_report(QERR_DEVICE_NOT_REMOVABLE, bdrv_get_device_name(bs));
 651         return -1;
 652     }
 653     if (!force && bdrv_is_locked(bs)) {
 654         qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
 655         return -1;
 656     }
 657     bdrv_close(bs);
 658     return 0;
 659 }
 660
 661 int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
 662 {
 663     BlockDriverState *bs;
 664     int force = qdict_get_try_bool(qdict, "force", 0);
 665     const char *filename = qdict_get_str(qdict, "device");
 666
 667     bs = bdrv_find(filename);
 668     if (!bs) {
 669         qerror_report(QERR_DEVICE_NOT_FOUND, filename);
 670         return -1;
 671     }
 672     return eject_device(mon, bs, force);
 673 }
 674
 675 int do_block_set_passwd(Monitor *mon, const QDict *qdict,
 676                         QObject **ret_data)
 677 {
 678     BlockDriverState *bs;
 679     int err;
 680
 681     bs = bdrv_find(qdict_get_str(qdict, "device"));
 682     if (!bs) {
 683         qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
 684         return -1;
 685     }
 686
 687     err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
 688     if (err == -EINVAL) {
 689         qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
 690         return -1;
 691     } else if (err < 0) {
 692         qerror_report(QERR_INVALID_PASSWORD);
 693         return -1;
 694     }
 695
 696     return 0;
 697 }
 698
 699 int do_change_block(Monitor *mon, const char *device,
 700                     const char *filename, const char *fmt)
 701 {
 702     BlockDriverState *bs;
 703     BlockDriver *drv = NULL;
 704     int bdrv_flags;
 705
 706     bs = bdrv_find(device);
 707     if (!bs) {
 708         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 709         return -1;
 710     }
 711     if (fmt) {
 712         drv = bdrv_find_whitelisted_format(fmt);
 713         if (!drv) {
 714             qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
 715             return -1;
 716         }
 717     }
 718     if (eject_device(mon, bs, 0) < 0) {
 719         return -1;
 720     }
 721     bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
 722     bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
 723     if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
 724         qerror_report(QERR_OPEN_FILE_FAILED, filename);
 725         return -1;
 726     }
 727     return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
 728 }
 729
 730 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 731 {
 732     const char *id = qdict_get_str(qdict, "id");
 733     BlockDriverState *bs;
 734
 735     bs = bdrv_find(id);
 736     if (!bs) {
 737         qerror_report(QERR_DEVICE_NOT_FOUND, id);
 738         return -1;
 739     }
 740     if (bdrv_in_use(bs)) {
 741         qerror_report(QERR_DEVICE_IN_USE, id);
 742         return -1;
 743     }
 744
 745     /* quiesce block driver; prevent further io */
 746     qemu_aio_flush();
 747     bdrv_flush(bs);
 748     bdrv_close(bs);
 749
 750     /* if we have a device associated with this BlockDriverState (bs->peer)
 751      * then we need to make the drive anonymous until the device
 752      * can be removed.  If this is a drive with no device backing
 753      * then we can just get rid of the block driver state right here.
 754      */
 755     if (bs->peer) {
 756         bdrv_make_anon(bs);
 757     } else {
 758         drive_uninit(drive_get_by_blockdev(bs));
 759     }
 760
 761     return 0;
 762 }
 763
 764 /*
 765  * XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
 766  * existing QERR_ macro mess is cleaned up.  A good example for better
 767  * error reports can be found in the qemu-img resize code.
 768  */
 769 int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
 770 {
 771     const char *device = qdict_get_str(qdict, "device");
 772     int64_t size = qdict_get_int(qdict, "size");
 773     BlockDriverState *bs;
 774
 775     bs = bdrv_find(device);
 776     if (!bs) {
 777         qerror_report(QERR_DEVICE_NOT_FOUND, device);
 778         return -1;
 779     }
 780
 781     if (size < 0) {
 782         qerror_report(QERR_UNDEFINED_ERROR);
 783         return -1;
 784     }
 785
 786     if (bdrv_truncate(bs, size)) {
 787         qerror_report(QERR_UNDEFINED_ERROR);
 788         return -1;
 789     }
 790
 791     return 0;
 792 }