1 /* 2 * QEMU System Emulator block driver 3 * 4 * Copyright (c) 2003 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #include "qemu/osdep.h" 25 #include "block/trace.h" 26 #include "block/block_int.h" 27 #include "block/blockjob.h" 28 #include "block/nbd.h" 29 #include "qemu/error-report.h" 30 #include "module_block.h" 31 #include "qemu/module.h" 32 #include "qapi/qmp/qerror.h" 33 #include "qapi/qmp/qbool.h" 34 #include "qapi/qmp/qjson.h" 35 #include "sysemu/block-backend.h" 36 #include "sysemu/sysemu.h" 37 #include "qemu/notify.h" 38 #include "qemu/coroutine.h" 39 #include "block/qapi.h" 40 #include "qmp-commands.h" 41 #include "qemu/timer.h" 42 #include "qapi-event.h" 43 #include "qemu/cutils.h" 44 #include "qemu/id.h" 45 #include "qapi/util.h" 46 47 #ifdef CONFIG_BSD 48 #include <sys/ioctl.h> 49 #include <sys/queue.h> 50 #ifndef __DragonFly__ 51 #include <sys/disk.h> 52 #endif 53 #endif 54 55 #ifdef _WIN32 56 #include <windows.h> 57 #endif 58 59 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ 60 61 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states = 62 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states); 63 64 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states = 65 QTAILQ_HEAD_INITIALIZER(all_bdrv_states); 66 67 static QLIST_HEAD(, BlockDriver) bdrv_drivers = 68 QLIST_HEAD_INITIALIZER(bdrv_drivers); 69 70 static BlockDriverState *bdrv_open_inherit(const char *filename, 71 const char *reference, 72 QDict *options, int flags, 73 BlockDriverState *parent, 74 const BdrvChildRole *child_role, 75 Error **errp); 76 77 /* If non-zero, use only whitelisted block drivers */ 78 static int use_bdrv_whitelist; 79 80 #ifdef _WIN32 81 static int is_windows_drive_prefix(const char *filename) 82 { 83 return (((filename[0] >= 'a' && filename[0] <= 'z') || 84 (filename[0] >= 'A' && filename[0] <= 'Z')) && 85 filename[1] == ':'); 86 } 87 88 int is_windows_drive(const char *filename) 89 { 90 if (is_windows_drive_prefix(filename) && 91 filename[2] == '\0') 92 return 1; 93 if (strstart(filename, "\\\\.\\", NULL) || 94 strstart(filename, "//./", NULL)) 95 return 1; 96 return 0; 97 } 98 #endif 99 100 size_t bdrv_opt_mem_align(BlockDriverState *bs) 101 { 102 if (!bs || !bs->drv) { 103 /* page size or 4k (hdd sector size) should be on the safe side */ 104 return MAX(4096, getpagesize()); 105 } 106 107 return bs->bl.opt_mem_alignment; 108 } 109 110 size_t bdrv_min_mem_align(BlockDriverState *bs) 111 { 112 if (!bs || !bs->drv) { 113 /* page size or 4k (hdd sector size) should be on the safe side */ 114 return MAX(4096, getpagesize()); 115 } 116 117 return bs->bl.min_mem_alignment; 118 } 119 120 /* check if the path starts with "<protocol>:" */ 121 int path_has_protocol(const char *path) 122 { 123 const char *p; 124 125 #ifdef _WIN32 126 if (is_windows_drive(path) || 127 is_windows_drive_prefix(path)) { 128 return 0; 129 } 130 p = path + strcspn(path, ":/\\"); 131 #else 132 p = path + strcspn(path, ":/"); 133 #endif 134 135 return *p == ':'; 136 } 137 138 int path_is_absolute(const char *path) 139 { 140 #ifdef _WIN32 141 /* specific case for names like: "\\.\d:" */ 142 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { 143 return 1; 144 } 145 return (*path == '/' || *path == '\\'); 146 #else 147 return (*path == '/'); 148 #endif 149 } 150 151 /* if filename is absolute, just copy it to dest. Otherwise, build a 152 path to it by considering it is relative to base_path. URL are 153 supported. */ 154 void path_combine(char *dest, int dest_size, 155 const char *base_path, 156 const char *filename) 157 { 158 const char *p, *p1; 159 int len; 160 161 if (dest_size <= 0) 162 return; 163 if (path_is_absolute(filename)) { 164 pstrcpy(dest, dest_size, filename); 165 } else { 166 const char *protocol_stripped = NULL; 167 168 if (path_has_protocol(base_path)) { 169 protocol_stripped = strchr(base_path, ':'); 170 if (protocol_stripped) { 171 protocol_stripped++; 172 } 173 } 174 p = protocol_stripped ?: base_path; 175 176 p1 = strrchr(base_path, '/'); 177 #ifdef _WIN32 178 { 179 const char *p2; 180 p2 = strrchr(base_path, '\\'); 181 if (!p1 || p2 > p1) 182 p1 = p2; 183 } 184 #endif 185 if (p1) 186 p1++; 187 else 188 p1 = base_path; 189 if (p1 > p) 190 p = p1; 191 len = p - base_path; 192 if (len > dest_size - 1) 193 len = dest_size - 1; 194 memcpy(dest, base_path, len); 195 dest[len] = '\0'; 196 pstrcat(dest, dest_size, filename); 197 } 198 } 199 200 /* 201 * Helper function for bdrv_parse_filename() implementations to remove optional 202 * protocol prefixes (especially "file:") from a filename and for putting the 203 * stripped filename into the options QDict if there is such a prefix. 204 */ 205 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 206 QDict *options) 207 { 208 if (strstart(filename, prefix, &filename)) { 209 /* Stripping the explicit protocol prefix may result in a protocol 210 * prefix being (wrongly) detected (if the filename contains a colon) */ 211 if (path_has_protocol(filename)) { 212 QString *fat_filename; 213 214 /* This means there is some colon before the first slash; therefore, 215 * this cannot be an absolute path */ 216 assert(!path_is_absolute(filename)); 217 218 /* And we can thus fix the protocol detection issue by prefixing it 219 * by "./" */ 220 fat_filename = qstring_from_str("./"); 221 qstring_append(fat_filename, filename); 222 223 assert(!path_has_protocol(qstring_get_str(fat_filename))); 224 225 qdict_put(options, "filename", fat_filename); 226 } else { 227 /* If no protocol prefix was detected, we can use the shortened 228 * filename as-is */ 229 qdict_put_str(options, "filename", filename); 230 } 231 } 232 } 233 234 235 /* Returns whether the image file is opened as read-only. Note that this can 236 * return false and writing to the image file is still not possible because the 237 * image is inactivated. */ 238 bool bdrv_is_read_only(BlockDriverState *bs) 239 { 240 return bs->read_only; 241 } 242 243 /* Returns whether the image file can be written to right now */ 244 bool bdrv_is_writable(BlockDriverState *bs) 245 { 246 return !bdrv_is_read_only(bs) && !(bs->open_flags & BDRV_O_INACTIVE); 247 } 248 249 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) 250 { 251 /* Do not set read_only if copy_on_read is enabled */ 252 if (bs->copy_on_read && read_only) { 253 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled", 254 bdrv_get_device_or_node_name(bs)); 255 return -EINVAL; 256 } 257 258 /* Do not clear read_only if it is prohibited */ 259 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR)) { 260 error_setg(errp, "Node '%s' is read only", 261 bdrv_get_device_or_node_name(bs)); 262 return -EPERM; 263 } 264 265 return 0; 266 } 267 268 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) 269 { 270 int ret = 0; 271 272 ret = bdrv_can_set_read_only(bs, read_only, errp); 273 if (ret < 0) { 274 return ret; 275 } 276 277 bs->read_only = read_only; 278 return 0; 279 } 280 281 void bdrv_get_full_backing_filename_from_filename(const char *backed, 282 const char *backing, 283 char *dest, size_t sz, 284 Error **errp) 285 { 286 if (backing[0] == '\0' || path_has_protocol(backing) || 287 path_is_absolute(backing)) 288 { 289 pstrcpy(dest, sz, backing); 290 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) { 291 error_setg(errp, "Cannot use relative backing file names for '%s'", 292 backed); 293 } else { 294 path_combine(dest, sz, backed, backing); 295 } 296 } 297 298 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, 299 Error **errp) 300 { 301 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename; 302 303 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file, 304 dest, sz, errp); 305 } 306 307 void bdrv_register(BlockDriver *bdrv) 308 { 309 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); 310 } 311 312 BlockDriverState *bdrv_new(void) 313 { 314 BlockDriverState *bs; 315 int i; 316 317 bs = g_new0(BlockDriverState, 1); 318 QLIST_INIT(&bs->dirty_bitmaps); 319 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 320 QLIST_INIT(&bs->op_blockers[i]); 321 } 322 notifier_with_return_list_init(&bs->before_write_notifiers); 323 qemu_co_mutex_init(&bs->reqs_lock); 324 qemu_mutex_init(&bs->dirty_bitmap_mutex); 325 bs->refcnt = 1; 326 bs->aio_context = qemu_get_aio_context(); 327 328 qemu_co_queue_init(&bs->flush_queue); 329 330 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); 331 332 return bs; 333 } 334 335 static BlockDriver *bdrv_do_find_format(const char *format_name) 336 { 337 BlockDriver *drv1; 338 339 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 340 if (!strcmp(drv1->format_name, format_name)) { 341 return drv1; 342 } 343 } 344 345 return NULL; 346 } 347 348 BlockDriver *bdrv_find_format(const char *format_name) 349 { 350 BlockDriver *drv1; 351 int i; 352 353 drv1 = bdrv_do_find_format(format_name); 354 if (drv1) { 355 return drv1; 356 } 357 358 /* The driver isn't registered, maybe we need to load a module */ 359 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { 360 if (!strcmp(block_driver_modules[i].format_name, format_name)) { 361 block_module_load_one(block_driver_modules[i].library_name); 362 break; 363 } 364 } 365 366 return bdrv_do_find_format(format_name); 367 } 368 369 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) 370 { 371 static const char *whitelist_rw[] = { 372 CONFIG_BDRV_RW_WHITELIST 373 }; 374 static const char *whitelist_ro[] = { 375 CONFIG_BDRV_RO_WHITELIST 376 }; 377 const char **p; 378 379 if (!whitelist_rw[0] && !whitelist_ro[0]) { 380 return 1; /* no whitelist, anything goes */ 381 } 382 383 for (p = whitelist_rw; *p; p++) { 384 if (!strcmp(drv->format_name, *p)) { 385 return 1; 386 } 387 } 388 if (read_only) { 389 for (p = whitelist_ro; *p; p++) { 390 if (!strcmp(drv->format_name, *p)) { 391 return 1; 392 } 393 } 394 } 395 return 0; 396 } 397 398 bool bdrv_uses_whitelist(void) 399 { 400 return use_bdrv_whitelist; 401 } 402 403 typedef struct CreateCo { 404 BlockDriver *drv; 405 char *filename; 406 QemuOpts *opts; 407 int ret; 408 Error *err; 409 } CreateCo; 410 411 static void coroutine_fn bdrv_create_co_entry(void *opaque) 412 { 413 Error *local_err = NULL; 414 int ret; 415 416 CreateCo *cco = opaque; 417 assert(cco->drv); 418 419 ret = cco->drv->bdrv_create(cco->filename, cco->opts, &local_err); 420 error_propagate(&cco->err, local_err); 421 cco->ret = ret; 422 } 423 424 int bdrv_create(BlockDriver *drv, const char* filename, 425 QemuOpts *opts, Error **errp) 426 { 427 int ret; 428 429 Coroutine *co; 430 CreateCo cco = { 431 .drv = drv, 432 .filename = g_strdup(filename), 433 .opts = opts, 434 .ret = NOT_DONE, 435 .err = NULL, 436 }; 437 438 if (!drv->bdrv_create) { 439 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); 440 ret = -ENOTSUP; 441 goto out; 442 } 443 444 if (qemu_in_coroutine()) { 445 /* Fast-path if already in coroutine context */ 446 bdrv_create_co_entry(&cco); 447 } else { 448 co = qemu_coroutine_create(bdrv_create_co_entry, &cco); 449 qemu_coroutine_enter(co); 450 while (cco.ret == NOT_DONE) { 451 aio_poll(qemu_get_aio_context(), true); 452 } 453 } 454 455 ret = cco.ret; 456 if (ret < 0) { 457 if (cco.err) { 458 error_propagate(errp, cco.err); 459 } else { 460 error_setg_errno(errp, -ret, "Could not create image"); 461 } 462 } 463 464 out: 465 g_free(cco.filename); 466 return ret; 467 } 468 469 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp) 470 { 471 BlockDriver *drv; 472 Error *local_err = NULL; 473 int ret; 474 475 drv = bdrv_find_protocol(filename, true, errp); 476 if (drv == NULL) { 477 return -ENOENT; 478 } 479 480 ret = bdrv_create(drv, filename, opts, &local_err); 481 error_propagate(errp, local_err); 482 return ret; 483 } 484 485 /** 486 * Try to get @bs's logical and physical block size. 487 * On success, store them in @bsz struct and return 0. 488 * On failure return -errno. 489 * @bs must not be empty. 490 */ 491 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz) 492 { 493 BlockDriver *drv = bs->drv; 494 495 if (drv && drv->bdrv_probe_blocksizes) { 496 return drv->bdrv_probe_blocksizes(bs, bsz); 497 } 498 499 return -ENOTSUP; 500 } 501 502 /** 503 * Try to get @bs's geometry (cyls, heads, sectors). 504 * On success, store them in @geo struct and return 0. 505 * On failure return -errno. 506 * @bs must not be empty. 507 */ 508 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo) 509 { 510 BlockDriver *drv = bs->drv; 511 512 if (drv && drv->bdrv_probe_geometry) { 513 return drv->bdrv_probe_geometry(bs, geo); 514 } 515 516 return -ENOTSUP; 517 } 518 519 /* 520 * Create a uniquely-named empty temporary file. 521 * Return 0 upon success, otherwise a negative errno value. 522 */ 523 int get_tmp_filename(char *filename, int size) 524 { 525 #ifdef _WIN32 526 char temp_dir[MAX_PATH]; 527 /* GetTempFileName requires that its output buffer (4th param) 528 have length MAX_PATH or greater. */ 529 assert(size >= MAX_PATH); 530 return (GetTempPath(MAX_PATH, temp_dir) 531 && GetTempFileName(temp_dir, "qem", 0, filename) 532 ? 0 : -GetLastError()); 533 #else 534 int fd; 535 const char *tmpdir; 536 tmpdir = getenv("TMPDIR"); 537 if (!tmpdir) { 538 tmpdir = "/var/tmp"; 539 } 540 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { 541 return -EOVERFLOW; 542 } 543 fd = mkstemp(filename); 544 if (fd < 0) { 545 return -errno; 546 } 547 if (close(fd) != 0) { 548 unlink(filename); 549 return -errno; 550 } 551 return 0; 552 #endif 553 } 554 555 /* 556 * Detect host devices. By convention, /dev/cdrom[N] is always 557 * recognized as a host CDROM. 558 */ 559 static BlockDriver *find_hdev_driver(const char *filename) 560 { 561 int score_max = 0, score; 562 BlockDriver *drv = NULL, *d; 563 564 QLIST_FOREACH(d, &bdrv_drivers, list) { 565 if (d->bdrv_probe_device) { 566 score = d->bdrv_probe_device(filename); 567 if (score > score_max) { 568 score_max = score; 569 drv = d; 570 } 571 } 572 } 573 574 return drv; 575 } 576 577 static BlockDriver *bdrv_do_find_protocol(const char *protocol) 578 { 579 BlockDriver *drv1; 580 581 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 582 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) { 583 return drv1; 584 } 585 } 586 587 return NULL; 588 } 589 590 BlockDriver *bdrv_find_protocol(const char *filename, 591 bool allow_protocol_prefix, 592 Error **errp) 593 { 594 BlockDriver *drv1; 595 char protocol[128]; 596 int len; 597 const char *p; 598 int i; 599 600 /* TODO Drivers without bdrv_file_open must be specified explicitly */ 601 602 /* 603 * XXX(hch): we really should not let host device detection 604 * override an explicit protocol specification, but moving this 605 * later breaks access to device names with colons in them. 606 * Thanks to the brain-dead persistent naming schemes on udev- 607 * based Linux systems those actually are quite common. 608 */ 609 drv1 = find_hdev_driver(filename); 610 if (drv1) { 611 return drv1; 612 } 613 614 if (!path_has_protocol(filename) || !allow_protocol_prefix) { 615 return &bdrv_file; 616 } 617 618 p = strchr(filename, ':'); 619 assert(p != NULL); 620 len = p - filename; 621 if (len > sizeof(protocol) - 1) 622 len = sizeof(protocol) - 1; 623 memcpy(protocol, filename, len); 624 protocol[len] = '\0'; 625 626 drv1 = bdrv_do_find_protocol(protocol); 627 if (drv1) { 628 return drv1; 629 } 630 631 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { 632 if (block_driver_modules[i].protocol_name && 633 !strcmp(block_driver_modules[i].protocol_name, protocol)) { 634 block_module_load_one(block_driver_modules[i].library_name); 635 break; 636 } 637 } 638 639 drv1 = bdrv_do_find_protocol(protocol); 640 if (!drv1) { 641 error_setg(errp, "Unknown protocol '%s'", protocol); 642 } 643 return drv1; 644 } 645 646 /* 647 * Guess image format by probing its contents. 648 * This is not a good idea when your image is raw (CVE-2008-2004), but 649 * we do it anyway for backward compatibility. 650 * 651 * @buf contains the image's first @buf_size bytes. 652 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE, 653 * but can be smaller if the image file is smaller) 654 * @filename is its filename. 655 * 656 * For all block drivers, call the bdrv_probe() method to get its 657 * probing score. 658 * Return the first block driver with the highest probing score. 659 */ 660 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 661 const char *filename) 662 { 663 int score_max = 0, score; 664 BlockDriver *drv = NULL, *d; 665 666 QLIST_FOREACH(d, &bdrv_drivers, list) { 667 if (d->bdrv_probe) { 668 score = d->bdrv_probe(buf, buf_size, filename); 669 if (score > score_max) { 670 score_max = score; 671 drv = d; 672 } 673 } 674 } 675 676 return drv; 677 } 678 679 static int find_image_format(BlockBackend *file, const char *filename, 680 BlockDriver **pdrv, Error **errp) 681 { 682 BlockDriver *drv; 683 uint8_t buf[BLOCK_PROBE_BUF_SIZE]; 684 int ret = 0; 685 686 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ 687 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) { 688 *pdrv = &bdrv_raw; 689 return ret; 690 } 691 692 ret = blk_pread(file, 0, buf, sizeof(buf)); 693 if (ret < 0) { 694 error_setg_errno(errp, -ret, "Could not read image for determining its " 695 "format"); 696 *pdrv = NULL; 697 return ret; 698 } 699 700 drv = bdrv_probe_all(buf, ret, filename); 701 if (!drv) { 702 error_setg(errp, "Could not determine image format: No compatible " 703 "driver found"); 704 ret = -ENOENT; 705 } 706 *pdrv = drv; 707 return ret; 708 } 709 710 /** 711 * Set the current 'total_sectors' value 712 * Return 0 on success, -errno on error. 713 */ 714 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint) 715 { 716 BlockDriver *drv = bs->drv; 717 718 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ 719 if (bdrv_is_sg(bs)) 720 return 0; 721 722 /* query actual device if possible, otherwise just trust the hint */ 723 if (drv->bdrv_getlength) { 724 int64_t length = drv->bdrv_getlength(bs); 725 if (length < 0) { 726 return length; 727 } 728 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); 729 } 730 731 bs->total_sectors = hint; 732 return 0; 733 } 734 735 /** 736 * Combines a QDict of new block driver @options with any missing options taken 737 * from @old_options, so that leaving out an option defaults to its old value. 738 */ 739 static void bdrv_join_options(BlockDriverState *bs, QDict *options, 740 QDict *old_options) 741 { 742 if (bs->drv && bs->drv->bdrv_join_options) { 743 bs->drv->bdrv_join_options(options, old_options); 744 } else { 745 qdict_join(options, old_options, false); 746 } 747 } 748 749 /** 750 * Set open flags for a given discard mode 751 * 752 * Return 0 on success, -1 if the discard mode was invalid. 753 */ 754 int bdrv_parse_discard_flags(const char *mode, int *flags) 755 { 756 *flags &= ~BDRV_O_UNMAP; 757 758 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { 759 /* do nothing */ 760 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { 761 *flags |= BDRV_O_UNMAP; 762 } else { 763 return -1; 764 } 765 766 return 0; 767 } 768 769 /** 770 * Set open flags for a given cache mode 771 * 772 * Return 0 on success, -1 if the cache mode was invalid. 773 */ 774 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough) 775 { 776 *flags &= ~BDRV_O_CACHE_MASK; 777 778 if (!strcmp(mode, "off") || !strcmp(mode, "none")) { 779 *writethrough = false; 780 *flags |= BDRV_O_NOCACHE; 781 } else if (!strcmp(mode, "directsync")) { 782 *writethrough = true; 783 *flags |= BDRV_O_NOCACHE; 784 } else if (!strcmp(mode, "writeback")) { 785 *writethrough = false; 786 } else if (!strcmp(mode, "unsafe")) { 787 *writethrough = false; 788 *flags |= BDRV_O_NO_FLUSH; 789 } else if (!strcmp(mode, "writethrough")) { 790 *writethrough = true; 791 } else { 792 return -1; 793 } 794 795 return 0; 796 } 797 798 static char *bdrv_child_get_parent_desc(BdrvChild *c) 799 { 800 BlockDriverState *parent = c->opaque; 801 return g_strdup(bdrv_get_device_or_node_name(parent)); 802 } 803 804 static void bdrv_child_cb_drained_begin(BdrvChild *child) 805 { 806 BlockDriverState *bs = child->opaque; 807 bdrv_drained_begin(bs); 808 } 809 810 static void bdrv_child_cb_drained_end(BdrvChild *child) 811 { 812 BlockDriverState *bs = child->opaque; 813 bdrv_drained_end(bs); 814 } 815 816 static int bdrv_child_cb_inactivate(BdrvChild *child) 817 { 818 BlockDriverState *bs = child->opaque; 819 assert(bs->open_flags & BDRV_O_INACTIVE); 820 return 0; 821 } 822 823 /* 824 * Returns the options and flags that a temporary snapshot should get, based on 825 * the originally requested flags (the originally requested image will have 826 * flags like a backing file) 827 */ 828 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options, 829 int parent_flags, QDict *parent_options) 830 { 831 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY; 832 833 /* For temporary files, unconditional cache=unsafe is fine */ 834 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off"); 835 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on"); 836 837 /* Copy the read-only option from the parent */ 838 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); 839 840 /* aio=native doesn't work for cache.direct=off, so disable it for the 841 * temporary snapshot */ 842 *child_flags &= ~BDRV_O_NATIVE_AIO; 843 } 844 845 /* 846 * Returns the options and flags that bs->file should get if a protocol driver 847 * is expected, based on the given options and flags for the parent BDS 848 */ 849 static void bdrv_inherited_options(int *child_flags, QDict *child_options, 850 int parent_flags, QDict *parent_options) 851 { 852 int flags = parent_flags; 853 854 /* Enable protocol handling, disable format probing for bs->file */ 855 flags |= BDRV_O_PROTOCOL; 856 857 /* If the cache mode isn't explicitly set, inherit direct and no-flush from 858 * the parent. */ 859 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); 860 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); 861 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); 862 863 /* Inherit the read-only option from the parent if it's not set */ 864 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); 865 866 /* Our block drivers take care to send flushes and respect unmap policy, 867 * so we can default to enable both on lower layers regardless of the 868 * corresponding parent options. */ 869 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap"); 870 871 /* Clear flags that only apply to the top layer */ 872 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ | 873 BDRV_O_NO_IO); 874 875 *child_flags = flags; 876 } 877 878 const BdrvChildRole child_file = { 879 .get_parent_desc = bdrv_child_get_parent_desc, 880 .inherit_options = bdrv_inherited_options, 881 .drained_begin = bdrv_child_cb_drained_begin, 882 .drained_end = bdrv_child_cb_drained_end, 883 .inactivate = bdrv_child_cb_inactivate, 884 }; 885 886 /* 887 * Returns the options and flags that bs->file should get if the use of formats 888 * (and not only protocols) is permitted for it, based on the given options and 889 * flags for the parent BDS 890 */ 891 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options, 892 int parent_flags, QDict *parent_options) 893 { 894 child_file.inherit_options(child_flags, child_options, 895 parent_flags, parent_options); 896 897 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO); 898 } 899 900 const BdrvChildRole child_format = { 901 .get_parent_desc = bdrv_child_get_parent_desc, 902 .inherit_options = bdrv_inherited_fmt_options, 903 .drained_begin = bdrv_child_cb_drained_begin, 904 .drained_end = bdrv_child_cb_drained_end, 905 .inactivate = bdrv_child_cb_inactivate, 906 }; 907 908 static void bdrv_backing_attach(BdrvChild *c) 909 { 910 BlockDriverState *parent = c->opaque; 911 BlockDriverState *backing_hd = c->bs; 912 913 assert(!parent->backing_blocker); 914 error_setg(&parent->backing_blocker, 915 "node is used as backing hd of '%s'", 916 bdrv_get_device_or_node_name(parent)); 917 918 parent->open_flags &= ~BDRV_O_NO_BACKING; 919 pstrcpy(parent->backing_file, sizeof(parent->backing_file), 920 backing_hd->filename); 921 pstrcpy(parent->backing_format, sizeof(parent->backing_format), 922 backing_hd->drv ? backing_hd->drv->format_name : ""); 923 924 bdrv_op_block_all(backing_hd, parent->backing_blocker); 925 /* Otherwise we won't be able to commit or stream */ 926 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, 927 parent->backing_blocker); 928 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM, 929 parent->backing_blocker); 930 /* 931 * We do backup in 3 ways: 932 * 1. drive backup 933 * The target bs is new opened, and the source is top BDS 934 * 2. blockdev backup 935 * Both the source and the target are top BDSes. 936 * 3. internal backup(used for block replication) 937 * Both the source and the target are backing file 938 * 939 * In case 1 and 2, neither the source nor the target is the backing file. 940 * In case 3, we will block the top BDS, so there is only one block job 941 * for the top BDS and its backing chain. 942 */ 943 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE, 944 parent->backing_blocker); 945 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET, 946 parent->backing_blocker); 947 } 948 949 static void bdrv_backing_detach(BdrvChild *c) 950 { 951 BlockDriverState *parent = c->opaque; 952 953 assert(parent->backing_blocker); 954 bdrv_op_unblock_all(c->bs, parent->backing_blocker); 955 error_free(parent->backing_blocker); 956 parent->backing_blocker = NULL; 957 } 958 959 /* 960 * Returns the options and flags that bs->backing should get, based on the 961 * given options and flags for the parent BDS 962 */ 963 static void bdrv_backing_options(int *child_flags, QDict *child_options, 964 int parent_flags, QDict *parent_options) 965 { 966 int flags = parent_flags; 967 968 /* The cache mode is inherited unmodified for backing files; except WCE, 969 * which is only applied on the top level (BlockBackend) */ 970 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); 971 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); 972 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); 973 974 /* backing files always opened read-only */ 975 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); 976 flags &= ~BDRV_O_COPY_ON_READ; 977 978 /* snapshot=on is handled on the top layer */ 979 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY); 980 981 *child_flags = flags; 982 } 983 984 const BdrvChildRole child_backing = { 985 .get_parent_desc = bdrv_child_get_parent_desc, 986 .attach = bdrv_backing_attach, 987 .detach = bdrv_backing_detach, 988 .inherit_options = bdrv_backing_options, 989 .drained_begin = bdrv_child_cb_drained_begin, 990 .drained_end = bdrv_child_cb_drained_end, 991 .inactivate = bdrv_child_cb_inactivate, 992 }; 993 994 static int bdrv_open_flags(BlockDriverState *bs, int flags) 995 { 996 int open_flags = flags; 997 998 /* 999 * Clear flags that are internal to the block layer before opening the 1000 * image. 1001 */ 1002 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL); 1003 1004 /* 1005 * Snapshots should be writable. 1006 */ 1007 if (flags & BDRV_O_TEMPORARY) { 1008 open_flags |= BDRV_O_RDWR; 1009 } 1010 1011 return open_flags; 1012 } 1013 1014 static void update_flags_from_options(int *flags, QemuOpts *opts) 1015 { 1016 *flags &= ~BDRV_O_CACHE_MASK; 1017 1018 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH)); 1019 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) { 1020 *flags |= BDRV_O_NO_FLUSH; 1021 } 1022 1023 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT)); 1024 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) { 1025 *flags |= BDRV_O_NOCACHE; 1026 } 1027 1028 *flags &= ~BDRV_O_RDWR; 1029 1030 assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY)); 1031 if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) { 1032 *flags |= BDRV_O_RDWR; 1033 } 1034 1035 } 1036 1037 static void update_options_from_flags(QDict *options, int flags) 1038 { 1039 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) { 1040 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE); 1041 } 1042 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) { 1043 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH, 1044 flags & BDRV_O_NO_FLUSH); 1045 } 1046 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) { 1047 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR)); 1048 } 1049 } 1050 1051 static void bdrv_assign_node_name(BlockDriverState *bs, 1052 const char *node_name, 1053 Error **errp) 1054 { 1055 char *gen_node_name = NULL; 1056 1057 if (!node_name) { 1058 node_name = gen_node_name = id_generate(ID_BLOCK); 1059 } else if (!id_wellformed(node_name)) { 1060 /* 1061 * Check for empty string or invalid characters, but not if it is 1062 * generated (generated names use characters not available to the user) 1063 */ 1064 error_setg(errp, "Invalid node name"); 1065 return; 1066 } 1067 1068 /* takes care of avoiding namespaces collisions */ 1069 if (blk_by_name(node_name)) { 1070 error_setg(errp, "node-name=%s is conflicting with a device id", 1071 node_name); 1072 goto out; 1073 } 1074 1075 /* takes care of avoiding duplicates node names */ 1076 if (bdrv_find_node(node_name)) { 1077 error_setg(errp, "Duplicate node name"); 1078 goto out; 1079 } 1080 1081 /* copy node name into the bs and insert it into the graph list */ 1082 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name); 1083 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list); 1084 out: 1085 g_free(gen_node_name); 1086 } 1087 1088 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, 1089 const char *node_name, QDict *options, 1090 int open_flags, Error **errp) 1091 { 1092 Error *local_err = NULL; 1093 int ret; 1094 1095 bdrv_assign_node_name(bs, node_name, &local_err); 1096 if (local_err) { 1097 error_propagate(errp, local_err); 1098 return -EINVAL; 1099 } 1100 1101 bs->drv = drv; 1102 bs->read_only = !(bs->open_flags & BDRV_O_RDWR); 1103 bs->opaque = g_malloc0(drv->instance_size); 1104 1105 if (drv->bdrv_file_open) { 1106 assert(!drv->bdrv_needs_filename || bs->filename[0]); 1107 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); 1108 } else if (drv->bdrv_open) { 1109 ret = drv->bdrv_open(bs, options, open_flags, &local_err); 1110 } else { 1111 ret = 0; 1112 } 1113 1114 if (ret < 0) { 1115 if (local_err) { 1116 error_propagate(errp, local_err); 1117 } else if (bs->filename[0]) { 1118 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); 1119 } else { 1120 error_setg_errno(errp, -ret, "Could not open image"); 1121 } 1122 goto free_and_fail; 1123 } 1124 1125 ret = refresh_total_sectors(bs, bs->total_sectors); 1126 if (ret < 0) { 1127 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 1128 goto free_and_fail; 1129 } 1130 1131 bdrv_refresh_limits(bs, &local_err); 1132 if (local_err) { 1133 error_propagate(errp, local_err); 1134 ret = -EINVAL; 1135 goto free_and_fail; 1136 } 1137 1138 assert(bdrv_opt_mem_align(bs) != 0); 1139 assert(bdrv_min_mem_align(bs) != 0); 1140 assert(is_power_of_2(bs->bl.request_alignment)); 1141 1142 return 0; 1143 1144 free_and_fail: 1145 /* FIXME Close bs first if already opened*/ 1146 g_free(bs->opaque); 1147 bs->opaque = NULL; 1148 bs->drv = NULL; 1149 return ret; 1150 } 1151 1152 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name, 1153 int flags, Error **errp) 1154 { 1155 BlockDriverState *bs; 1156 int ret; 1157 1158 bs = bdrv_new(); 1159 bs->open_flags = flags; 1160 bs->explicit_options = qdict_new(); 1161 bs->options = qdict_new(); 1162 bs->opaque = NULL; 1163 1164 update_options_from_flags(bs->options, flags); 1165 1166 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp); 1167 if (ret < 0) { 1168 QDECREF(bs->explicit_options); 1169 QDECREF(bs->options); 1170 bdrv_unref(bs); 1171 return NULL; 1172 } 1173 1174 return bs; 1175 } 1176 1177 QemuOptsList bdrv_runtime_opts = { 1178 .name = "bdrv_common", 1179 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head), 1180 .desc = { 1181 { 1182 .name = "node-name", 1183 .type = QEMU_OPT_STRING, 1184 .help = "Node name of the block device node", 1185 }, 1186 { 1187 .name = "driver", 1188 .type = QEMU_OPT_STRING, 1189 .help = "Block driver to use for the node", 1190 }, 1191 { 1192 .name = BDRV_OPT_CACHE_DIRECT, 1193 .type = QEMU_OPT_BOOL, 1194 .help = "Bypass software writeback cache on the host", 1195 }, 1196 { 1197 .name = BDRV_OPT_CACHE_NO_FLUSH, 1198 .type = QEMU_OPT_BOOL, 1199 .help = "Ignore flush requests", 1200 }, 1201 { 1202 .name = BDRV_OPT_READ_ONLY, 1203 .type = QEMU_OPT_BOOL, 1204 .help = "Node is opened in read-only mode", 1205 }, 1206 { 1207 .name = "detect-zeroes", 1208 .type = QEMU_OPT_STRING, 1209 .help = "try to optimize zero writes (off, on, unmap)", 1210 }, 1211 { 1212 .name = "discard", 1213 .type = QEMU_OPT_STRING, 1214 .help = "discard operation (ignore/off, unmap/on)", 1215 }, 1216 { 1217 .name = BDRV_OPT_FORCE_SHARE, 1218 .type = QEMU_OPT_BOOL, 1219 .help = "always accept other writers (default: off)", 1220 }, 1221 { /* end of list */ } 1222 }, 1223 }; 1224 1225 /* 1226 * Common part for opening disk images and files 1227 * 1228 * Removes all processed options from *options. 1229 */ 1230 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, 1231 QDict *options, Error **errp) 1232 { 1233 int ret, open_flags; 1234 const char *filename; 1235 const char *driver_name = NULL; 1236 const char *node_name = NULL; 1237 const char *discard; 1238 const char *detect_zeroes; 1239 QemuOpts *opts; 1240 BlockDriver *drv; 1241 Error *local_err = NULL; 1242 1243 assert(bs->file == NULL); 1244 assert(options != NULL && bs->options != options); 1245 1246 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); 1247 qemu_opts_absorb_qdict(opts, options, &local_err); 1248 if (local_err) { 1249 error_propagate(errp, local_err); 1250 ret = -EINVAL; 1251 goto fail_opts; 1252 } 1253 1254 update_flags_from_options(&bs->open_flags, opts); 1255 1256 driver_name = qemu_opt_get(opts, "driver"); 1257 drv = bdrv_find_format(driver_name); 1258 assert(drv != NULL); 1259 1260 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false); 1261 1262 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) { 1263 error_setg(errp, 1264 BDRV_OPT_FORCE_SHARE 1265 "=on can only be used with read-only images"); 1266 ret = -EINVAL; 1267 goto fail_opts; 1268 } 1269 1270 if (file != NULL) { 1271 filename = blk_bs(file)->filename; 1272 } else { 1273 /* 1274 * Caution: while qdict_get_try_str() is fine, getting 1275 * non-string types would require more care. When @options 1276 * come from -blockdev or blockdev_add, its members are typed 1277 * according to the QAPI schema, but when they come from 1278 * -drive, they're all QString. 1279 */ 1280 filename = qdict_get_try_str(options, "filename"); 1281 } 1282 1283 if (drv->bdrv_needs_filename && (!filename || !filename[0])) { 1284 error_setg(errp, "The '%s' block driver requires a file name", 1285 drv->format_name); 1286 ret = -EINVAL; 1287 goto fail_opts; 1288 } 1289 1290 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags, 1291 drv->format_name); 1292 1293 bs->read_only = !(bs->open_flags & BDRV_O_RDWR); 1294 1295 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { 1296 error_setg(errp, 1297 !bs->read_only && bdrv_is_whitelisted(drv, true) 1298 ? "Driver '%s' can only be used for read-only devices" 1299 : "Driver '%s' is not whitelisted", 1300 drv->format_name); 1301 ret = -ENOTSUP; 1302 goto fail_opts; 1303 } 1304 1305 /* bdrv_new() and bdrv_close() make it so */ 1306 assert(atomic_read(&bs->copy_on_read) == 0); 1307 1308 if (bs->open_flags & BDRV_O_COPY_ON_READ) { 1309 if (!bs->read_only) { 1310 bdrv_enable_copy_on_read(bs); 1311 } else { 1312 error_setg(errp, "Can't use copy-on-read on read-only device"); 1313 ret = -EINVAL; 1314 goto fail_opts; 1315 } 1316 } 1317 1318 discard = qemu_opt_get(opts, "discard"); 1319 if (discard != NULL) { 1320 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) { 1321 error_setg(errp, "Invalid discard option"); 1322 ret = -EINVAL; 1323 goto fail_opts; 1324 } 1325 } 1326 1327 detect_zeroes = qemu_opt_get(opts, "detect-zeroes"); 1328 if (detect_zeroes) { 1329 BlockdevDetectZeroesOptions value = 1330 qapi_enum_parse(BlockdevDetectZeroesOptions_lookup, 1331 detect_zeroes, 1332 BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX, 1333 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, 1334 &local_err); 1335 if (local_err) { 1336 error_propagate(errp, local_err); 1337 ret = -EINVAL; 1338 goto fail_opts; 1339 } 1340 1341 if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP && 1342 !(bs->open_flags & BDRV_O_UNMAP)) 1343 { 1344 error_setg(errp, "setting detect-zeroes to unmap is not allowed " 1345 "without setting discard operation to unmap"); 1346 ret = -EINVAL; 1347 goto fail_opts; 1348 } 1349 1350 bs->detect_zeroes = value; 1351 } 1352 1353 if (filename != NULL) { 1354 pstrcpy(bs->filename, sizeof(bs->filename), filename); 1355 } else { 1356 bs->filename[0] = '\0'; 1357 } 1358 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename); 1359 1360 /* Open the image, either directly or using a protocol */ 1361 open_flags = bdrv_open_flags(bs, bs->open_flags); 1362 node_name = qemu_opt_get(opts, "node-name"); 1363 1364 assert(!drv->bdrv_file_open || file == NULL); 1365 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp); 1366 if (ret < 0) { 1367 goto fail_opts; 1368 } 1369 1370 qemu_opts_del(opts); 1371 return 0; 1372 1373 fail_opts: 1374 qemu_opts_del(opts); 1375 return ret; 1376 } 1377 1378 static QDict *parse_json_filename(const char *filename, Error **errp) 1379 { 1380 QObject *options_obj; 1381 QDict *options; 1382 int ret; 1383 1384 ret = strstart(filename, "json:", &filename); 1385 assert(ret); 1386 1387 options_obj = qobject_from_json(filename, errp); 1388 if (!options_obj) { 1389 /* Work around qobject_from_json() lossage TODO fix that */ 1390 if (errp && !*errp) { 1391 error_setg(errp, "Could not parse the JSON options"); 1392 return NULL; 1393 } 1394 error_prepend(errp, "Could not parse the JSON options: "); 1395 return NULL; 1396 } 1397 1398 options = qobject_to_qdict(options_obj); 1399 if (!options) { 1400 qobject_decref(options_obj); 1401 error_setg(errp, "Invalid JSON object given"); 1402 return NULL; 1403 } 1404 1405 qdict_flatten(options); 1406 1407 return options; 1408 } 1409 1410 static void parse_json_protocol(QDict *options, const char **pfilename, 1411 Error **errp) 1412 { 1413 QDict *json_options; 1414 Error *local_err = NULL; 1415 1416 /* Parse json: pseudo-protocol */ 1417 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) { 1418 return; 1419 } 1420 1421 json_options = parse_json_filename(*pfilename, &local_err); 1422 if (local_err) { 1423 error_propagate(errp, local_err); 1424 return; 1425 } 1426 1427 /* Options given in the filename have lower priority than options 1428 * specified directly */ 1429 qdict_join(options, json_options, false); 1430 QDECREF(json_options); 1431 *pfilename = NULL; 1432 } 1433 1434 /* 1435 * Fills in default options for opening images and converts the legacy 1436 * filename/flags pair to option QDict entries. 1437 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a 1438 * block driver has been specified explicitly. 1439 */ 1440 static int bdrv_fill_options(QDict **options, const char *filename, 1441 int *flags, Error **errp) 1442 { 1443 const char *drvname; 1444 bool protocol = *flags & BDRV_O_PROTOCOL; 1445 bool parse_filename = false; 1446 BlockDriver *drv = NULL; 1447 Error *local_err = NULL; 1448 1449 /* 1450 * Caution: while qdict_get_try_str() is fine, getting non-string 1451 * types would require more care. When @options come from 1452 * -blockdev or blockdev_add, its members are typed according to 1453 * the QAPI schema, but when they come from -drive, they're all 1454 * QString. 1455 */ 1456 drvname = qdict_get_try_str(*options, "driver"); 1457 if (drvname) { 1458 drv = bdrv_find_format(drvname); 1459 if (!drv) { 1460 error_setg(errp, "Unknown driver '%s'", drvname); 1461 return -ENOENT; 1462 } 1463 /* If the user has explicitly specified the driver, this choice should 1464 * override the BDRV_O_PROTOCOL flag */ 1465 protocol = drv->bdrv_file_open; 1466 } 1467 1468 if (protocol) { 1469 *flags |= BDRV_O_PROTOCOL; 1470 } else { 1471 *flags &= ~BDRV_O_PROTOCOL; 1472 } 1473 1474 /* Translate cache options from flags into options */ 1475 update_options_from_flags(*options, *flags); 1476 1477 /* Fetch the file name from the options QDict if necessary */ 1478 if (protocol && filename) { 1479 if (!qdict_haskey(*options, "filename")) { 1480 qdict_put_str(*options, "filename", filename); 1481 parse_filename = true; 1482 } else { 1483 error_setg(errp, "Can't specify 'file' and 'filename' options at " 1484 "the same time"); 1485 return -EINVAL; 1486 } 1487 } 1488 1489 /* Find the right block driver */ 1490 /* See cautionary note on accessing @options above */ 1491 filename = qdict_get_try_str(*options, "filename"); 1492 1493 if (!drvname && protocol) { 1494 if (filename) { 1495 drv = bdrv_find_protocol(filename, parse_filename, errp); 1496 if (!drv) { 1497 return -EINVAL; 1498 } 1499 1500 drvname = drv->format_name; 1501 qdict_put_str(*options, "driver", drvname); 1502 } else { 1503 error_setg(errp, "Must specify either driver or file"); 1504 return -EINVAL; 1505 } 1506 } 1507 1508 assert(drv || !protocol); 1509 1510 /* Driver-specific filename parsing */ 1511 if (drv && drv->bdrv_parse_filename && parse_filename) { 1512 drv->bdrv_parse_filename(filename, *options, &local_err); 1513 if (local_err) { 1514 error_propagate(errp, local_err); 1515 return -EINVAL; 1516 } 1517 1518 if (!drv->bdrv_needs_filename) { 1519 qdict_del(*options, "filename"); 1520 } 1521 } 1522 1523 return 0; 1524 } 1525 1526 static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1527 GSList *ignore_children, Error **errp); 1528 static void bdrv_child_abort_perm_update(BdrvChild *c); 1529 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); 1530 1531 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, 1532 BdrvChild *c, 1533 const BdrvChildRole *role, 1534 uint64_t parent_perm, uint64_t parent_shared, 1535 uint64_t *nperm, uint64_t *nshared) 1536 { 1537 if (bs->drv && bs->drv->bdrv_child_perm) { 1538 bs->drv->bdrv_child_perm(bs, c, role, 1539 parent_perm, parent_shared, 1540 nperm, nshared); 1541 } 1542 if (child_bs && child_bs->force_share) { 1543 *nshared = BLK_PERM_ALL; 1544 } 1545 } 1546 1547 /* 1548 * Check whether permissions on this node can be changed in a way that 1549 * @cumulative_perms and @cumulative_shared_perms are the new cumulative 1550 * permissions of all its parents. This involves checking whether all necessary 1551 * permission changes to child nodes can be performed. 1552 * 1553 * A call to this function must always be followed by a call to bdrv_set_perm() 1554 * or bdrv_abort_perm_update(). 1555 */ 1556 static int bdrv_check_perm(BlockDriverState *bs, uint64_t cumulative_perms, 1557 uint64_t cumulative_shared_perms, 1558 GSList *ignore_children, Error **errp) 1559 { 1560 BlockDriver *drv = bs->drv; 1561 BdrvChild *c; 1562 int ret; 1563 1564 /* Write permissions never work with read-only images */ 1565 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && 1566 !bdrv_is_writable(bs)) 1567 { 1568 error_setg(errp, "Block node is read-only"); 1569 return -EPERM; 1570 } 1571 1572 /* Check this node */ 1573 if (!drv) { 1574 return 0; 1575 } 1576 1577 if (drv->bdrv_check_perm) { 1578 return drv->bdrv_check_perm(bs, cumulative_perms, 1579 cumulative_shared_perms, errp); 1580 } 1581 1582 /* Drivers that never have children can omit .bdrv_child_perm() */ 1583 if (!drv->bdrv_child_perm) { 1584 assert(QLIST_EMPTY(&bs->children)); 1585 return 0; 1586 } 1587 1588 /* Check all children */ 1589 QLIST_FOREACH(c, &bs->children, next) { 1590 uint64_t cur_perm, cur_shared; 1591 bdrv_child_perm(bs, c->bs, c, c->role, 1592 cumulative_perms, cumulative_shared_perms, 1593 &cur_perm, &cur_shared); 1594 ret = bdrv_child_check_perm(c, cur_perm, cur_shared, ignore_children, 1595 errp); 1596 if (ret < 0) { 1597 return ret; 1598 } 1599 } 1600 1601 return 0; 1602 } 1603 1604 /* 1605 * Notifies drivers that after a previous bdrv_check_perm() call, the 1606 * permission update is not performed and any preparations made for it (e.g. 1607 * taken file locks) need to be undone. 1608 * 1609 * This function recursively notifies all child nodes. 1610 */ 1611 static void bdrv_abort_perm_update(BlockDriverState *bs) 1612 { 1613 BlockDriver *drv = bs->drv; 1614 BdrvChild *c; 1615 1616 if (!drv) { 1617 return; 1618 } 1619 1620 if (drv->bdrv_abort_perm_update) { 1621 drv->bdrv_abort_perm_update(bs); 1622 } 1623 1624 QLIST_FOREACH(c, &bs->children, next) { 1625 bdrv_child_abort_perm_update(c); 1626 } 1627 } 1628 1629 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms, 1630 uint64_t cumulative_shared_perms) 1631 { 1632 BlockDriver *drv = bs->drv; 1633 BdrvChild *c; 1634 1635 if (!drv) { 1636 return; 1637 } 1638 1639 /* Update this node */ 1640 if (drv->bdrv_set_perm) { 1641 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms); 1642 } 1643 1644 /* Drivers that never have children can omit .bdrv_child_perm() */ 1645 if (!drv->bdrv_child_perm) { 1646 assert(QLIST_EMPTY(&bs->children)); 1647 return; 1648 } 1649 1650 /* Update all children */ 1651 QLIST_FOREACH(c, &bs->children, next) { 1652 uint64_t cur_perm, cur_shared; 1653 bdrv_child_perm(bs, c->bs, c, c->role, 1654 cumulative_perms, cumulative_shared_perms, 1655 &cur_perm, &cur_shared); 1656 bdrv_child_set_perm(c, cur_perm, cur_shared); 1657 } 1658 } 1659 1660 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, 1661 uint64_t *shared_perm) 1662 { 1663 BdrvChild *c; 1664 uint64_t cumulative_perms = 0; 1665 uint64_t cumulative_shared_perms = BLK_PERM_ALL; 1666 1667 QLIST_FOREACH(c, &bs->parents, next_parent) { 1668 cumulative_perms |= c->perm; 1669 cumulative_shared_perms &= c->shared_perm; 1670 } 1671 1672 *perm = cumulative_perms; 1673 *shared_perm = cumulative_shared_perms; 1674 } 1675 1676 static char *bdrv_child_user_desc(BdrvChild *c) 1677 { 1678 if (c->role->get_parent_desc) { 1679 return c->role->get_parent_desc(c); 1680 } 1681 1682 return g_strdup("another user"); 1683 } 1684 1685 char *bdrv_perm_names(uint64_t perm) 1686 { 1687 struct perm_name { 1688 uint64_t perm; 1689 const char *name; 1690 } permissions[] = { 1691 { BLK_PERM_CONSISTENT_READ, "consistent read" }, 1692 { BLK_PERM_WRITE, "write" }, 1693 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" }, 1694 { BLK_PERM_RESIZE, "resize" }, 1695 { BLK_PERM_GRAPH_MOD, "change children" }, 1696 { 0, NULL } 1697 }; 1698 1699 char *result = g_strdup(""); 1700 struct perm_name *p; 1701 1702 for (p = permissions; p->name; p++) { 1703 if (perm & p->perm) { 1704 char *old = result; 1705 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name); 1706 g_free(old); 1707 } 1708 } 1709 1710 return result; 1711 } 1712 1713 /* 1714 * Checks whether a new reference to @bs can be added if the new user requires 1715 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is 1716 * set, the BdrvChild objects in this list are ignored in the calculations; 1717 * this allows checking permission updates for an existing reference. 1718 * 1719 * Needs to be followed by a call to either bdrv_set_perm() or 1720 * bdrv_abort_perm_update(). */ 1721 static int bdrv_check_update_perm(BlockDriverState *bs, uint64_t new_used_perm, 1722 uint64_t new_shared_perm, 1723 GSList *ignore_children, Error **errp) 1724 { 1725 BdrvChild *c; 1726 uint64_t cumulative_perms = new_used_perm; 1727 uint64_t cumulative_shared_perms = new_shared_perm; 1728 1729 /* There is no reason why anyone couldn't tolerate write_unchanged */ 1730 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); 1731 1732 QLIST_FOREACH(c, &bs->parents, next_parent) { 1733 if (g_slist_find(ignore_children, c)) { 1734 continue; 1735 } 1736 1737 if ((new_used_perm & c->shared_perm) != new_used_perm) { 1738 char *user = bdrv_child_user_desc(c); 1739 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); 1740 error_setg(errp, "Conflicts with use by %s as '%s', which does not " 1741 "allow '%s' on %s", 1742 user, c->name, perm_names, bdrv_get_node_name(c->bs)); 1743 g_free(user); 1744 g_free(perm_names); 1745 return -EPERM; 1746 } 1747 1748 if ((c->perm & new_shared_perm) != c->perm) { 1749 char *user = bdrv_child_user_desc(c); 1750 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm); 1751 error_setg(errp, "Conflicts with use by %s as '%s', which uses " 1752 "'%s' on %s", 1753 user, c->name, perm_names, bdrv_get_node_name(c->bs)); 1754 g_free(user); 1755 g_free(perm_names); 1756 return -EPERM; 1757 } 1758 1759 cumulative_perms |= c->perm; 1760 cumulative_shared_perms &= c->shared_perm; 1761 } 1762 1763 return bdrv_check_perm(bs, cumulative_perms, cumulative_shared_perms, 1764 ignore_children, errp); 1765 } 1766 1767 /* Needs to be followed by a call to either bdrv_child_set_perm() or 1768 * bdrv_child_abort_perm_update(). */ 1769 static int bdrv_child_check_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1770 GSList *ignore_children, Error **errp) 1771 { 1772 int ret; 1773 1774 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); 1775 ret = bdrv_check_update_perm(c->bs, perm, shared, ignore_children, errp); 1776 g_slist_free(ignore_children); 1777 1778 return ret; 1779 } 1780 1781 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) 1782 { 1783 uint64_t cumulative_perms, cumulative_shared_perms; 1784 1785 c->perm = perm; 1786 c->shared_perm = shared; 1787 1788 bdrv_get_cumulative_perm(c->bs, &cumulative_perms, 1789 &cumulative_shared_perms); 1790 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms); 1791 } 1792 1793 static void bdrv_child_abort_perm_update(BdrvChild *c) 1794 { 1795 bdrv_abort_perm_update(c->bs); 1796 } 1797 1798 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1799 Error **errp) 1800 { 1801 int ret; 1802 1803 ret = bdrv_child_check_perm(c, perm, shared, NULL, errp); 1804 if (ret < 0) { 1805 bdrv_child_abort_perm_update(c); 1806 return ret; 1807 } 1808 1809 bdrv_child_set_perm(c, perm, shared); 1810 1811 return 0; 1812 } 1813 1814 #define DEFAULT_PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \ 1815 | BLK_PERM_WRITE \ 1816 | BLK_PERM_WRITE_UNCHANGED \ 1817 | BLK_PERM_RESIZE) 1818 #define DEFAULT_PERM_UNCHANGED (BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH) 1819 1820 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 1821 const BdrvChildRole *role, 1822 uint64_t perm, uint64_t shared, 1823 uint64_t *nperm, uint64_t *nshared) 1824 { 1825 if (c == NULL) { 1826 *nperm = perm & DEFAULT_PERM_PASSTHROUGH; 1827 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; 1828 return; 1829 } 1830 1831 *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) | 1832 (c->perm & DEFAULT_PERM_UNCHANGED); 1833 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | 1834 (c->shared_perm & DEFAULT_PERM_UNCHANGED); 1835 } 1836 1837 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 1838 const BdrvChildRole *role, 1839 uint64_t perm, uint64_t shared, 1840 uint64_t *nperm, uint64_t *nshared) 1841 { 1842 bool backing = (role == &child_backing); 1843 assert(role == &child_backing || role == &child_file); 1844 1845 if (!backing) { 1846 /* Apart from the modifications below, the same permissions are 1847 * forwarded and left alone as for filters */ 1848 bdrv_filter_default_perms(bs, c, role, perm, shared, &perm, &shared); 1849 1850 /* Format drivers may touch metadata even if the guest doesn't write */ 1851 if (bdrv_is_writable(bs)) { 1852 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE; 1853 } 1854 1855 /* bs->file always needs to be consistent because of the metadata. We 1856 * can never allow other users to resize or write to it. */ 1857 perm |= BLK_PERM_CONSISTENT_READ; 1858 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); 1859 } else { 1860 /* We want consistent read from backing files if the parent needs it. 1861 * No other operations are performed on backing files. */ 1862 perm &= BLK_PERM_CONSISTENT_READ; 1863 1864 /* If the parent can deal with changing data, we're okay with a 1865 * writable and resizable backing file. */ 1866 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */ 1867 if (shared & BLK_PERM_WRITE) { 1868 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE; 1869 } else { 1870 shared = 0; 1871 } 1872 1873 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | 1874 BLK_PERM_WRITE_UNCHANGED; 1875 } 1876 1877 if (bs->open_flags & BDRV_O_INACTIVE) { 1878 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE; 1879 } 1880 1881 *nperm = perm; 1882 *nshared = shared; 1883 } 1884 1885 static void bdrv_replace_child_noperm(BdrvChild *child, 1886 BlockDriverState *new_bs) 1887 { 1888 BlockDriverState *old_bs = child->bs; 1889 1890 if (old_bs && new_bs) { 1891 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); 1892 } 1893 if (old_bs) { 1894 if (old_bs->quiesce_counter && child->role->drained_end) { 1895 child->role->drained_end(child); 1896 } 1897 if (child->role->detach) { 1898 child->role->detach(child); 1899 } 1900 QLIST_REMOVE(child, next_parent); 1901 } 1902 1903 child->bs = new_bs; 1904 1905 if (new_bs) { 1906 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); 1907 if (new_bs->quiesce_counter && child->role->drained_begin) { 1908 child->role->drained_begin(child); 1909 } 1910 1911 if (child->role->attach) { 1912 child->role->attach(child); 1913 } 1914 } 1915 } 1916 1917 /* 1918 * Updates @child to change its reference to point to @new_bs, including 1919 * checking and applying the necessary permisson updates both to the old node 1920 * and to @new_bs. 1921 * 1922 * NULL is passed as @new_bs for removing the reference before freeing @child. 1923 * 1924 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this 1925 * function uses bdrv_set_perm() to update the permissions according to the new 1926 * reference that @new_bs gets. 1927 */ 1928 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) 1929 { 1930 BlockDriverState *old_bs = child->bs; 1931 uint64_t perm, shared_perm; 1932 1933 if (old_bs) { 1934 /* Update permissions for old node. This is guaranteed to succeed 1935 * because we're just taking a parent away, so we're loosening 1936 * restrictions. */ 1937 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm); 1938 bdrv_check_perm(old_bs, perm, shared_perm, NULL, &error_abort); 1939 bdrv_set_perm(old_bs, perm, shared_perm); 1940 } 1941 1942 bdrv_replace_child_noperm(child, new_bs); 1943 1944 if (new_bs) { 1945 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); 1946 bdrv_set_perm(new_bs, perm, shared_perm); 1947 } 1948 } 1949 1950 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 1951 const char *child_name, 1952 const BdrvChildRole *child_role, 1953 uint64_t perm, uint64_t shared_perm, 1954 void *opaque, Error **errp) 1955 { 1956 BdrvChild *child; 1957 int ret; 1958 1959 ret = bdrv_check_update_perm(child_bs, perm, shared_perm, NULL, errp); 1960 if (ret < 0) { 1961 bdrv_abort_perm_update(child_bs); 1962 return NULL; 1963 } 1964 1965 child = g_new(BdrvChild, 1); 1966 *child = (BdrvChild) { 1967 .bs = NULL, 1968 .name = g_strdup(child_name), 1969 .role = child_role, 1970 .perm = perm, 1971 .shared_perm = shared_perm, 1972 .opaque = opaque, 1973 }; 1974 1975 /* This performs the matching bdrv_set_perm() for the above check. */ 1976 bdrv_replace_child(child, child_bs); 1977 1978 return child; 1979 } 1980 1981 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, 1982 BlockDriverState *child_bs, 1983 const char *child_name, 1984 const BdrvChildRole *child_role, 1985 Error **errp) 1986 { 1987 BdrvChild *child; 1988 uint64_t perm, shared_perm; 1989 1990 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); 1991 1992 assert(parent_bs->drv); 1993 assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs)); 1994 bdrv_child_perm(parent_bs, child_bs, NULL, child_role, 1995 perm, shared_perm, &perm, &shared_perm); 1996 1997 child = bdrv_root_attach_child(child_bs, child_name, child_role, 1998 perm, shared_perm, parent_bs, errp); 1999 if (child == NULL) { 2000 return NULL; 2001 } 2002 2003 QLIST_INSERT_HEAD(&parent_bs->children, child, next); 2004 return child; 2005 } 2006 2007 static void bdrv_detach_child(BdrvChild *child) 2008 { 2009 if (child->next.le_prev) { 2010 QLIST_REMOVE(child, next); 2011 child->next.le_prev = NULL; 2012 } 2013 2014 bdrv_replace_child(child, NULL); 2015 2016 g_free(child->name); 2017 g_free(child); 2018 } 2019 2020 void bdrv_root_unref_child(BdrvChild *child) 2021 { 2022 BlockDriverState *child_bs; 2023 2024 child_bs = child->bs; 2025 bdrv_detach_child(child); 2026 bdrv_unref(child_bs); 2027 } 2028 2029 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) 2030 { 2031 if (child == NULL) { 2032 return; 2033 } 2034 2035 if (child->bs->inherits_from == parent) { 2036 BdrvChild *c; 2037 2038 /* Remove inherits_from only when the last reference between parent and 2039 * child->bs goes away. */ 2040 QLIST_FOREACH(c, &parent->children, next) { 2041 if (c != child && c->bs == child->bs) { 2042 break; 2043 } 2044 } 2045 if (c == NULL) { 2046 child->bs->inherits_from = NULL; 2047 } 2048 } 2049 2050 bdrv_root_unref_child(child); 2051 } 2052 2053 2054 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load) 2055 { 2056 BdrvChild *c; 2057 QLIST_FOREACH(c, &bs->parents, next_parent) { 2058 if (c->role->change_media) { 2059 c->role->change_media(c, load); 2060 } 2061 } 2062 } 2063 2064 static void bdrv_parent_cb_resize(BlockDriverState *bs) 2065 { 2066 BdrvChild *c; 2067 QLIST_FOREACH(c, &bs->parents, next_parent) { 2068 if (c->role->resize) { 2069 c->role->resize(c); 2070 } 2071 } 2072 } 2073 2074 /* 2075 * Sets the backing file link of a BDS. A new reference is created; callers 2076 * which don't need their own reference any more must call bdrv_unref(). 2077 */ 2078 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, 2079 Error **errp) 2080 { 2081 if (backing_hd) { 2082 bdrv_ref(backing_hd); 2083 } 2084 2085 if (bs->backing) { 2086 bdrv_unref_child(bs, bs->backing); 2087 } 2088 2089 if (!backing_hd) { 2090 bs->backing = NULL; 2091 goto out; 2092 } 2093 2094 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing, 2095 errp); 2096 if (!bs->backing) { 2097 bdrv_unref(backing_hd); 2098 } 2099 2100 bdrv_refresh_filename(bs); 2101 2102 out: 2103 bdrv_refresh_limits(bs, NULL); 2104 } 2105 2106 /* 2107 * Opens the backing file for a BlockDriverState if not yet open 2108 * 2109 * bdref_key specifies the key for the image's BlockdevRef in the options QDict. 2110 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict 2111 * itself, all options starting with "${bdref_key}." are considered part of the 2112 * BlockdevRef. 2113 * 2114 * TODO Can this be unified with bdrv_open_image()? 2115 */ 2116 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, 2117 const char *bdref_key, Error **errp) 2118 { 2119 char *backing_filename = g_malloc0(PATH_MAX); 2120 char *bdref_key_dot; 2121 const char *reference = NULL; 2122 int ret = 0; 2123 BlockDriverState *backing_hd; 2124 QDict *options; 2125 QDict *tmp_parent_options = NULL; 2126 Error *local_err = NULL; 2127 2128 if (bs->backing != NULL) { 2129 goto free_exit; 2130 } 2131 2132 /* NULL means an empty set of options */ 2133 if (parent_options == NULL) { 2134 tmp_parent_options = qdict_new(); 2135 parent_options = tmp_parent_options; 2136 } 2137 2138 bs->open_flags &= ~BDRV_O_NO_BACKING; 2139 2140 bdref_key_dot = g_strdup_printf("%s.", bdref_key); 2141 qdict_extract_subqdict(parent_options, &options, bdref_key_dot); 2142 g_free(bdref_key_dot); 2143 2144 /* 2145 * Caution: while qdict_get_try_str() is fine, getting non-string 2146 * types would require more care. When @parent_options come from 2147 * -blockdev or blockdev_add, its members are typed according to 2148 * the QAPI schema, but when they come from -drive, they're all 2149 * QString. 2150 */ 2151 reference = qdict_get_try_str(parent_options, bdref_key); 2152 if (reference || qdict_haskey(options, "file.filename")) { 2153 backing_filename[0] = '\0'; 2154 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { 2155 QDECREF(options); 2156 goto free_exit; 2157 } else { 2158 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX, 2159 &local_err); 2160 if (local_err) { 2161 ret = -EINVAL; 2162 error_propagate(errp, local_err); 2163 QDECREF(options); 2164 goto free_exit; 2165 } 2166 } 2167 2168 if (!bs->drv || !bs->drv->supports_backing) { 2169 ret = -EINVAL; 2170 error_setg(errp, "Driver doesn't support backing files"); 2171 QDECREF(options); 2172 goto free_exit; 2173 } 2174 2175 if (bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { 2176 qdict_put_str(options, "driver", bs->backing_format); 2177 } 2178 2179 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL, 2180 reference, options, 0, bs, &child_backing, 2181 errp); 2182 if (!backing_hd) { 2183 bs->open_flags |= BDRV_O_NO_BACKING; 2184 error_prepend(errp, "Could not open backing file: "); 2185 ret = -EINVAL; 2186 goto free_exit; 2187 } 2188 2189 /* Hook up the backing file link; drop our reference, bs owns the 2190 * backing_hd reference now */ 2191 bdrv_set_backing_hd(bs, backing_hd, &local_err); 2192 bdrv_unref(backing_hd); 2193 if (local_err) { 2194 error_propagate(errp, local_err); 2195 ret = -EINVAL; 2196 goto free_exit; 2197 } 2198 2199 qdict_del(parent_options, bdref_key); 2200 2201 free_exit: 2202 g_free(backing_filename); 2203 QDECREF(tmp_parent_options); 2204 return ret; 2205 } 2206 2207 static BlockDriverState * 2208 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, 2209 BlockDriverState *parent, const BdrvChildRole *child_role, 2210 bool allow_none, Error **errp) 2211 { 2212 BlockDriverState *bs = NULL; 2213 QDict *image_options; 2214 char *bdref_key_dot; 2215 const char *reference; 2216 2217 assert(child_role != NULL); 2218 2219 bdref_key_dot = g_strdup_printf("%s.", bdref_key); 2220 qdict_extract_subqdict(options, &image_options, bdref_key_dot); 2221 g_free(bdref_key_dot); 2222 2223 /* 2224 * Caution: while qdict_get_try_str() is fine, getting non-string 2225 * types would require more care. When @options come from 2226 * -blockdev or blockdev_add, its members are typed according to 2227 * the QAPI schema, but when they come from -drive, they're all 2228 * QString. 2229 */ 2230 reference = qdict_get_try_str(options, bdref_key); 2231 if (!filename && !reference && !qdict_size(image_options)) { 2232 if (!allow_none) { 2233 error_setg(errp, "A block device must be specified for \"%s\"", 2234 bdref_key); 2235 } 2236 QDECREF(image_options); 2237 goto done; 2238 } 2239 2240 bs = bdrv_open_inherit(filename, reference, image_options, 0, 2241 parent, child_role, errp); 2242 if (!bs) { 2243 goto done; 2244 } 2245 2246 done: 2247 qdict_del(options, bdref_key); 2248 return bs; 2249 } 2250 2251 /* 2252 * Opens a disk image whose options are given as BlockdevRef in another block 2253 * device's options. 2254 * 2255 * If allow_none is true, no image will be opened if filename is false and no 2256 * BlockdevRef is given. NULL will be returned, but errp remains unset. 2257 * 2258 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict. 2259 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict 2260 * itself, all options starting with "${bdref_key}." are considered part of the 2261 * BlockdevRef. 2262 * 2263 * The BlockdevRef will be removed from the options QDict. 2264 */ 2265 BdrvChild *bdrv_open_child(const char *filename, 2266 QDict *options, const char *bdref_key, 2267 BlockDriverState *parent, 2268 const BdrvChildRole *child_role, 2269 bool allow_none, Error **errp) 2270 { 2271 BdrvChild *c; 2272 BlockDriverState *bs; 2273 2274 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role, 2275 allow_none, errp); 2276 if (bs == NULL) { 2277 return NULL; 2278 } 2279 2280 c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp); 2281 if (!c) { 2282 bdrv_unref(bs); 2283 return NULL; 2284 } 2285 2286 return c; 2287 } 2288 2289 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, 2290 int flags, 2291 QDict *snapshot_options, 2292 Error **errp) 2293 { 2294 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ 2295 char *tmp_filename = g_malloc0(PATH_MAX + 1); 2296 int64_t total_size; 2297 QemuOpts *opts = NULL; 2298 BlockDriverState *bs_snapshot = NULL; 2299 Error *local_err = NULL; 2300 int ret; 2301 2302 /* if snapshot, we create a temporary backing file and open it 2303 instead of opening 'filename' directly */ 2304 2305 /* Get the required size from the image */ 2306 total_size = bdrv_getlength(bs); 2307 if (total_size < 0) { 2308 error_setg_errno(errp, -total_size, "Could not get image size"); 2309 goto out; 2310 } 2311 2312 /* Create the temporary image */ 2313 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1); 2314 if (ret < 0) { 2315 error_setg_errno(errp, -ret, "Could not get temporary filename"); 2316 goto out; 2317 } 2318 2319 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, 2320 &error_abort); 2321 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort); 2322 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp); 2323 qemu_opts_del(opts); 2324 if (ret < 0) { 2325 error_prepend(errp, "Could not create temporary overlay '%s': ", 2326 tmp_filename); 2327 goto out; 2328 } 2329 2330 /* Prepare options QDict for the temporary file */ 2331 qdict_put_str(snapshot_options, "file.driver", "file"); 2332 qdict_put_str(snapshot_options, "file.filename", tmp_filename); 2333 qdict_put_str(snapshot_options, "driver", "qcow2"); 2334 2335 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp); 2336 snapshot_options = NULL; 2337 if (!bs_snapshot) { 2338 goto out; 2339 } 2340 2341 /* bdrv_append() consumes a strong reference to bs_snapshot 2342 * (i.e. it will call bdrv_unref() on it) even on error, so in 2343 * order to be able to return one, we have to increase 2344 * bs_snapshot's refcount here */ 2345 bdrv_ref(bs_snapshot); 2346 bdrv_append(bs_snapshot, bs, &local_err); 2347 if (local_err) { 2348 error_propagate(errp, local_err); 2349 bs_snapshot = NULL; 2350 goto out; 2351 } 2352 2353 out: 2354 QDECREF(snapshot_options); 2355 g_free(tmp_filename); 2356 return bs_snapshot; 2357 } 2358 2359 /* 2360 * Opens a disk image (raw, qcow2, vmdk, ...) 2361 * 2362 * options is a QDict of options to pass to the block drivers, or NULL for an 2363 * empty set of options. The reference to the QDict belongs to the block layer 2364 * after the call (even on failure), so if the caller intends to reuse the 2365 * dictionary, it needs to use QINCREF() before calling bdrv_open. 2366 * 2367 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there. 2368 * If it is not NULL, the referenced BDS will be reused. 2369 * 2370 * The reference parameter may be used to specify an existing block device which 2371 * should be opened. If specified, neither options nor a filename may be given, 2372 * nor can an existing BDS be reused (that is, *pbs has to be NULL). 2373 */ 2374 static BlockDriverState *bdrv_open_inherit(const char *filename, 2375 const char *reference, 2376 QDict *options, int flags, 2377 BlockDriverState *parent, 2378 const BdrvChildRole *child_role, 2379 Error **errp) 2380 { 2381 int ret; 2382 BlockBackend *file = NULL; 2383 BlockDriverState *bs; 2384 BlockDriver *drv = NULL; 2385 const char *drvname; 2386 const char *backing; 2387 Error *local_err = NULL; 2388 QDict *snapshot_options = NULL; 2389 int snapshot_flags = 0; 2390 2391 assert(!child_role || !flags); 2392 assert(!child_role == !parent); 2393 2394 if (reference) { 2395 bool options_non_empty = options ? qdict_size(options) : false; 2396 QDECREF(options); 2397 2398 if (filename || options_non_empty) { 2399 error_setg(errp, "Cannot reference an existing block device with " 2400 "additional options or a new filename"); 2401 return NULL; 2402 } 2403 2404 bs = bdrv_lookup_bs(reference, reference, errp); 2405 if (!bs) { 2406 return NULL; 2407 } 2408 2409 bdrv_ref(bs); 2410 return bs; 2411 } 2412 2413 bs = bdrv_new(); 2414 2415 /* NULL means an empty set of options */ 2416 if (options == NULL) { 2417 options = qdict_new(); 2418 } 2419 2420 /* json: syntax counts as explicit options, as if in the QDict */ 2421 parse_json_protocol(options, &filename, &local_err); 2422 if (local_err) { 2423 goto fail; 2424 } 2425 2426 bs->explicit_options = qdict_clone_shallow(options); 2427 2428 if (child_role) { 2429 bs->inherits_from = parent; 2430 child_role->inherit_options(&flags, options, 2431 parent->open_flags, parent->options); 2432 } 2433 2434 ret = bdrv_fill_options(&options, filename, &flags, &local_err); 2435 if (local_err) { 2436 goto fail; 2437 } 2438 2439 /* 2440 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. 2441 * Caution: getting a boolean member of @options requires care. 2442 * When @options come from -blockdev or blockdev_add, members are 2443 * typed according to the QAPI schema, but when they come from 2444 * -drive, they're all QString. 2445 */ 2446 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && 2447 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { 2448 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); 2449 } else { 2450 flags &= ~BDRV_O_RDWR; 2451 } 2452 2453 if (flags & BDRV_O_SNAPSHOT) { 2454 snapshot_options = qdict_new(); 2455 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options, 2456 flags, options); 2457 /* Let bdrv_backing_options() override "read-only" */ 2458 qdict_del(options, BDRV_OPT_READ_ONLY); 2459 bdrv_backing_options(&flags, options, flags, options); 2460 } 2461 2462 bs->open_flags = flags; 2463 bs->options = options; 2464 options = qdict_clone_shallow(options); 2465 2466 /* Find the right image format driver */ 2467 /* See cautionary note on accessing @options above */ 2468 drvname = qdict_get_try_str(options, "driver"); 2469 if (drvname) { 2470 drv = bdrv_find_format(drvname); 2471 if (!drv) { 2472 error_setg(errp, "Unknown driver: '%s'", drvname); 2473 goto fail; 2474 } 2475 } 2476 2477 assert(drvname || !(flags & BDRV_O_PROTOCOL)); 2478 2479 /* See cautionary note on accessing @options above */ 2480 backing = qdict_get_try_str(options, "backing"); 2481 if (backing && *backing == '\0') { 2482 flags |= BDRV_O_NO_BACKING; 2483 qdict_del(options, "backing"); 2484 } 2485 2486 /* Open image file without format layer. This BlockBackend is only used for 2487 * probing, the block drivers will do their own bdrv_open_child() for the 2488 * same BDS, which is why we put the node name back into options. */ 2489 if ((flags & BDRV_O_PROTOCOL) == 0) { 2490 BlockDriverState *file_bs; 2491 2492 file_bs = bdrv_open_child_bs(filename, options, "file", bs, 2493 &child_file, true, &local_err); 2494 if (local_err) { 2495 goto fail; 2496 } 2497 if (file_bs != NULL) { 2498 file = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); 2499 blk_insert_bs(file, file_bs, &local_err); 2500 bdrv_unref(file_bs); 2501 if (local_err) { 2502 goto fail; 2503 } 2504 2505 qdict_put_str(options, "file", bdrv_get_node_name(file_bs)); 2506 } 2507 } 2508 2509 /* Image format probing */ 2510 bs->probed = !drv; 2511 if (!drv && file) { 2512 ret = find_image_format(file, filename, &drv, &local_err); 2513 if (ret < 0) { 2514 goto fail; 2515 } 2516 /* 2517 * This option update would logically belong in bdrv_fill_options(), 2518 * but we first need to open bs->file for the probing to work, while 2519 * opening bs->file already requires the (mostly) final set of options 2520 * so that cache mode etc. can be inherited. 2521 * 2522 * Adding the driver later is somewhat ugly, but it's not an option 2523 * that would ever be inherited, so it's correct. We just need to make 2524 * sure to update both bs->options (which has the full effective 2525 * options for bs) and options (which has file.* already removed). 2526 */ 2527 qdict_put_str(bs->options, "driver", drv->format_name); 2528 qdict_put_str(options, "driver", drv->format_name); 2529 } else if (!drv) { 2530 error_setg(errp, "Must specify either driver or file"); 2531 goto fail; 2532 } 2533 2534 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */ 2535 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open); 2536 /* file must be NULL if a protocol BDS is about to be created 2537 * (the inverse results in an error message from bdrv_open_common()) */ 2538 assert(!(flags & BDRV_O_PROTOCOL) || !file); 2539 2540 /* Open the image */ 2541 ret = bdrv_open_common(bs, file, options, &local_err); 2542 if (ret < 0) { 2543 goto fail; 2544 } 2545 2546 if (file) { 2547 blk_unref(file); 2548 file = NULL; 2549 } 2550 2551 /* If there is a backing file, use it */ 2552 if ((flags & BDRV_O_NO_BACKING) == 0) { 2553 ret = bdrv_open_backing_file(bs, options, "backing", &local_err); 2554 if (ret < 0) { 2555 goto close_and_fail; 2556 } 2557 } 2558 2559 bdrv_refresh_filename(bs); 2560 2561 /* Check if any unknown options were used */ 2562 if (qdict_size(options) != 0) { 2563 const QDictEntry *entry = qdict_first(options); 2564 if (flags & BDRV_O_PROTOCOL) { 2565 error_setg(errp, "Block protocol '%s' doesn't support the option " 2566 "'%s'", drv->format_name, entry->key); 2567 } else { 2568 error_setg(errp, 2569 "Block format '%s' does not support the option '%s'", 2570 drv->format_name, entry->key); 2571 } 2572 2573 goto close_and_fail; 2574 } 2575 2576 if (!bdrv_key_required(bs)) { 2577 bdrv_parent_cb_change_media(bs, true); 2578 } else if (!runstate_check(RUN_STATE_PRELAUNCH) 2579 && !runstate_check(RUN_STATE_INMIGRATE) 2580 && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */ 2581 error_setg(errp, 2582 "Guest must be stopped for opening of encrypted image"); 2583 goto close_and_fail; 2584 } 2585 2586 QDECREF(options); 2587 2588 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the 2589 * temporary snapshot afterwards. */ 2590 if (snapshot_flags) { 2591 BlockDriverState *snapshot_bs; 2592 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags, 2593 snapshot_options, &local_err); 2594 snapshot_options = NULL; 2595 if (local_err) { 2596 goto close_and_fail; 2597 } 2598 /* We are not going to return bs but the overlay on top of it 2599 * (snapshot_bs); thus, we have to drop the strong reference to bs 2600 * (which we obtained by calling bdrv_new()). bs will not be deleted, 2601 * though, because the overlay still has a reference to it. */ 2602 bdrv_unref(bs); 2603 bs = snapshot_bs; 2604 } 2605 2606 return bs; 2607 2608 fail: 2609 blk_unref(file); 2610 if (bs->file != NULL) { 2611 bdrv_unref_child(bs, bs->file); 2612 } 2613 QDECREF(snapshot_options); 2614 QDECREF(bs->explicit_options); 2615 QDECREF(bs->options); 2616 QDECREF(options); 2617 bs->options = NULL; 2618 bdrv_unref(bs); 2619 error_propagate(errp, local_err); 2620 return NULL; 2621 2622 close_and_fail: 2623 bdrv_unref(bs); 2624 QDECREF(snapshot_options); 2625 QDECREF(options); 2626 error_propagate(errp, local_err); 2627 return NULL; 2628 } 2629 2630 BlockDriverState *bdrv_open(const char *filename, const char *reference, 2631 QDict *options, int flags, Error **errp) 2632 { 2633 return bdrv_open_inherit(filename, reference, options, flags, NULL, 2634 NULL, errp); 2635 } 2636 2637 typedef struct BlockReopenQueueEntry { 2638 bool prepared; 2639 BDRVReopenState state; 2640 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; 2641 } BlockReopenQueueEntry; 2642 2643 /* 2644 * Adds a BlockDriverState to a simple queue for an atomic, transactional 2645 * reopen of multiple devices. 2646 * 2647 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT 2648 * already performed, or alternatively may be NULL a new BlockReopenQueue will 2649 * be created and initialized. This newly created BlockReopenQueue should be 2650 * passed back in for subsequent calls that are intended to be of the same 2651 * atomic 'set'. 2652 * 2653 * bs is the BlockDriverState to add to the reopen queue. 2654 * 2655 * options contains the changed options for the associated bs 2656 * (the BlockReopenQueue takes ownership) 2657 * 2658 * flags contains the open flags for the associated bs 2659 * 2660 * returns a pointer to bs_queue, which is either the newly allocated 2661 * bs_queue, or the existing bs_queue being used. 2662 * 2663 */ 2664 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, 2665 BlockDriverState *bs, 2666 QDict *options, 2667 int flags, 2668 const BdrvChildRole *role, 2669 QDict *parent_options, 2670 int parent_flags) 2671 { 2672 assert(bs != NULL); 2673 2674 BlockReopenQueueEntry *bs_entry; 2675 BdrvChild *child; 2676 QDict *old_options, *explicit_options; 2677 2678 if (bs_queue == NULL) { 2679 bs_queue = g_new0(BlockReopenQueue, 1); 2680 QSIMPLEQ_INIT(bs_queue); 2681 } 2682 2683 if (!options) { 2684 options = qdict_new(); 2685 } 2686 2687 /* Check if this BlockDriverState is already in the queue */ 2688 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 2689 if (bs == bs_entry->state.bs) { 2690 break; 2691 } 2692 } 2693 2694 /* 2695 * Precedence of options: 2696 * 1. Explicitly passed in options (highest) 2697 * 2. Set in flags (only for top level) 2698 * 3. Retained from explicitly set options of bs 2699 * 4. Inherited from parent node 2700 * 5. Retained from effective options of bs 2701 */ 2702 2703 if (!parent_options) { 2704 /* 2705 * Any setting represented by flags is always updated. If the 2706 * corresponding QDict option is set, it takes precedence. Otherwise 2707 * the flag is translated into a QDict option. The old setting of bs is 2708 * not considered. 2709 */ 2710 update_options_from_flags(options, flags); 2711 } 2712 2713 /* Old explicitly set values (don't overwrite by inherited value) */ 2714 if (bs_entry) { 2715 old_options = qdict_clone_shallow(bs_entry->state.explicit_options); 2716 } else { 2717 old_options = qdict_clone_shallow(bs->explicit_options); 2718 } 2719 bdrv_join_options(bs, options, old_options); 2720 QDECREF(old_options); 2721 2722 explicit_options = qdict_clone_shallow(options); 2723 2724 /* Inherit from parent node */ 2725 if (parent_options) { 2726 assert(!flags); 2727 role->inherit_options(&flags, options, parent_flags, parent_options); 2728 } 2729 2730 /* Old values are used for options that aren't set yet */ 2731 old_options = qdict_clone_shallow(bs->options); 2732 bdrv_join_options(bs, options, old_options); 2733 QDECREF(old_options); 2734 2735 /* bdrv_open() masks this flag out */ 2736 flags &= ~BDRV_O_PROTOCOL; 2737 2738 QLIST_FOREACH(child, &bs->children, next) { 2739 QDict *new_child_options; 2740 char *child_key_dot; 2741 2742 /* reopen can only change the options of block devices that were 2743 * implicitly created and inherited options. For other (referenced) 2744 * block devices, a syntax like "backing.foo" results in an error. */ 2745 if (child->bs->inherits_from != bs) { 2746 continue; 2747 } 2748 2749 child_key_dot = g_strdup_printf("%s.", child->name); 2750 qdict_extract_subqdict(options, &new_child_options, child_key_dot); 2751 g_free(child_key_dot); 2752 2753 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0, 2754 child->role, options, flags); 2755 } 2756 2757 if (!bs_entry) { 2758 bs_entry = g_new0(BlockReopenQueueEntry, 1); 2759 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); 2760 } else { 2761 QDECREF(bs_entry->state.options); 2762 QDECREF(bs_entry->state.explicit_options); 2763 } 2764 2765 bs_entry->state.bs = bs; 2766 bs_entry->state.options = options; 2767 bs_entry->state.explicit_options = explicit_options; 2768 bs_entry->state.flags = flags; 2769 2770 return bs_queue; 2771 } 2772 2773 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, 2774 BlockDriverState *bs, 2775 QDict *options, int flags) 2776 { 2777 return bdrv_reopen_queue_child(bs_queue, bs, options, flags, 2778 NULL, NULL, 0); 2779 } 2780 2781 /* 2782 * Reopen multiple BlockDriverStates atomically & transactionally. 2783 * 2784 * The queue passed in (bs_queue) must have been built up previous 2785 * via bdrv_reopen_queue(). 2786 * 2787 * Reopens all BDS specified in the queue, with the appropriate 2788 * flags. All devices are prepared for reopen, and failure of any 2789 * device will cause all device changes to be abandonded, and intermediate 2790 * data cleaned up. 2791 * 2792 * If all devices prepare successfully, then the changes are committed 2793 * to all devices. 2794 * 2795 */ 2796 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp) 2797 { 2798 int ret = -1; 2799 BlockReopenQueueEntry *bs_entry, *next; 2800 Error *local_err = NULL; 2801 2802 assert(bs_queue != NULL); 2803 2804 aio_context_release(ctx); 2805 bdrv_drain_all_begin(); 2806 aio_context_acquire(ctx); 2807 2808 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 2809 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { 2810 error_propagate(errp, local_err); 2811 goto cleanup; 2812 } 2813 bs_entry->prepared = true; 2814 } 2815 2816 /* If we reach this point, we have success and just need to apply the 2817 * changes 2818 */ 2819 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 2820 bdrv_reopen_commit(&bs_entry->state); 2821 } 2822 2823 ret = 0; 2824 2825 cleanup: 2826 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { 2827 if (ret && bs_entry->prepared) { 2828 bdrv_reopen_abort(&bs_entry->state); 2829 } else if (ret) { 2830 QDECREF(bs_entry->state.explicit_options); 2831 } 2832 QDECREF(bs_entry->state.options); 2833 g_free(bs_entry); 2834 } 2835 g_free(bs_queue); 2836 2837 bdrv_drain_all_end(); 2838 2839 return ret; 2840 } 2841 2842 2843 /* Reopen a single BlockDriverState with the specified flags. */ 2844 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) 2845 { 2846 int ret = -1; 2847 Error *local_err = NULL; 2848 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags); 2849 2850 ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err); 2851 if (local_err != NULL) { 2852 error_propagate(errp, local_err); 2853 } 2854 return ret; 2855 } 2856 2857 2858 /* 2859 * Prepares a BlockDriverState for reopen. All changes are staged in the 2860 * 'opaque' field of the BDRVReopenState, which is used and allocated by 2861 * the block driver layer .bdrv_reopen_prepare() 2862 * 2863 * bs is the BlockDriverState to reopen 2864 * flags are the new open flags 2865 * queue is the reopen queue 2866 * 2867 * Returns 0 on success, non-zero on error. On error errp will be set 2868 * as well. 2869 * 2870 * On failure, bdrv_reopen_abort() will be called to clean up any data. 2871 * It is the responsibility of the caller to then call the abort() or 2872 * commit() for any other BDS that have been left in a prepare() state 2873 * 2874 */ 2875 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 2876 Error **errp) 2877 { 2878 int ret = -1; 2879 Error *local_err = NULL; 2880 BlockDriver *drv; 2881 QemuOpts *opts; 2882 const char *value; 2883 bool read_only; 2884 2885 assert(reopen_state != NULL); 2886 assert(reopen_state->bs->drv != NULL); 2887 drv = reopen_state->bs->drv; 2888 2889 /* Process generic block layer options */ 2890 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); 2891 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err); 2892 if (local_err) { 2893 error_propagate(errp, local_err); 2894 ret = -EINVAL; 2895 goto error; 2896 } 2897 2898 update_flags_from_options(&reopen_state->flags, opts); 2899 2900 /* node-name and driver must be unchanged. Put them back into the QDict, so 2901 * that they are checked at the end of this function. */ 2902 value = qemu_opt_get(opts, "node-name"); 2903 if (value) { 2904 qdict_put_str(reopen_state->options, "node-name", value); 2905 } 2906 2907 value = qemu_opt_get(opts, "driver"); 2908 if (value) { 2909 qdict_put_str(reopen_state->options, "driver", value); 2910 } 2911 2912 /* If we are to stay read-only, do not allow permission change 2913 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is 2914 * not set, or if the BDS still has copy_on_read enabled */ 2915 read_only = !(reopen_state->flags & BDRV_O_RDWR); 2916 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, &local_err); 2917 if (local_err) { 2918 error_propagate(errp, local_err); 2919 goto error; 2920 } 2921 2922 2923 ret = bdrv_flush(reopen_state->bs); 2924 if (ret) { 2925 error_setg_errno(errp, -ret, "Error flushing drive"); 2926 goto error; 2927 } 2928 2929 if (drv->bdrv_reopen_prepare) { 2930 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); 2931 if (ret) { 2932 if (local_err != NULL) { 2933 error_propagate(errp, local_err); 2934 } else { 2935 error_setg(errp, "failed while preparing to reopen image '%s'", 2936 reopen_state->bs->filename); 2937 } 2938 goto error; 2939 } 2940 } else { 2941 /* It is currently mandatory to have a bdrv_reopen_prepare() 2942 * handler for each supported drv. */ 2943 error_setg(errp, "Block format '%s' used by node '%s' " 2944 "does not support reopening files", drv->format_name, 2945 bdrv_get_device_or_node_name(reopen_state->bs)); 2946 ret = -1; 2947 goto error; 2948 } 2949 2950 /* Options that are not handled are only okay if they are unchanged 2951 * compared to the old state. It is expected that some options are only 2952 * used for the initial open, but not reopen (e.g. filename) */ 2953 if (qdict_size(reopen_state->options)) { 2954 const QDictEntry *entry = qdict_first(reopen_state->options); 2955 2956 do { 2957 QString *new_obj = qobject_to_qstring(entry->value); 2958 const char *new = qstring_get_str(new_obj); 2959 /* 2960 * Caution: while qdict_get_try_str() is fine, getting 2961 * non-string types would require more care. When 2962 * bs->options come from -blockdev or blockdev_add, its 2963 * members are typed according to the QAPI schema, but 2964 * when they come from -drive, they're all QString. 2965 */ 2966 const char *old = qdict_get_try_str(reopen_state->bs->options, 2967 entry->key); 2968 2969 if (!old || strcmp(new, old)) { 2970 error_setg(errp, "Cannot change the option '%s'", entry->key); 2971 ret = -EINVAL; 2972 goto error; 2973 } 2974 } while ((entry = qdict_next(reopen_state->options, entry))); 2975 } 2976 2977 ret = 0; 2978 2979 error: 2980 qemu_opts_del(opts); 2981 return ret; 2982 } 2983 2984 /* 2985 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and 2986 * makes them final by swapping the staging BlockDriverState contents into 2987 * the active BlockDriverState contents. 2988 */ 2989 void bdrv_reopen_commit(BDRVReopenState *reopen_state) 2990 { 2991 BlockDriver *drv; 2992 2993 assert(reopen_state != NULL); 2994 drv = reopen_state->bs->drv; 2995 assert(drv != NULL); 2996 2997 /* If there are any driver level actions to take */ 2998 if (drv->bdrv_reopen_commit) { 2999 drv->bdrv_reopen_commit(reopen_state); 3000 } 3001 3002 /* set BDS specific flags now */ 3003 QDECREF(reopen_state->bs->explicit_options); 3004 3005 reopen_state->bs->explicit_options = reopen_state->explicit_options; 3006 reopen_state->bs->open_flags = reopen_state->flags; 3007 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); 3008 3009 bdrv_refresh_limits(reopen_state->bs, NULL); 3010 } 3011 3012 /* 3013 * Abort the reopen, and delete and free the staged changes in 3014 * reopen_state 3015 */ 3016 void bdrv_reopen_abort(BDRVReopenState *reopen_state) 3017 { 3018 BlockDriver *drv; 3019 3020 assert(reopen_state != NULL); 3021 drv = reopen_state->bs->drv; 3022 assert(drv != NULL); 3023 3024 if (drv->bdrv_reopen_abort) { 3025 drv->bdrv_reopen_abort(reopen_state); 3026 } 3027 3028 QDECREF(reopen_state->explicit_options); 3029 } 3030 3031 3032 static void bdrv_close(BlockDriverState *bs) 3033 { 3034 BdrvAioNotifier *ban, *ban_next; 3035 3036 assert(!bs->job); 3037 assert(!bs->refcnt); 3038 3039 bdrv_drained_begin(bs); /* complete I/O */ 3040 bdrv_flush(bs); 3041 bdrv_drain(bs); /* in case flush left pending I/O */ 3042 3043 bdrv_release_named_dirty_bitmaps(bs); 3044 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 3045 3046 if (bs->drv) { 3047 BdrvChild *child, *next; 3048 3049 bs->drv->bdrv_close(bs); 3050 bs->drv = NULL; 3051 3052 bdrv_set_backing_hd(bs, NULL, &error_abort); 3053 3054 if (bs->file != NULL) { 3055 bdrv_unref_child(bs, bs->file); 3056 bs->file = NULL; 3057 } 3058 3059 QLIST_FOREACH_SAFE(child, &bs->children, next, next) { 3060 /* TODO Remove bdrv_unref() from drivers' close function and use 3061 * bdrv_unref_child() here */ 3062 if (child->bs->inherits_from == bs) { 3063 child->bs->inherits_from = NULL; 3064 } 3065 bdrv_detach_child(child); 3066 } 3067 3068 g_free(bs->opaque); 3069 bs->opaque = NULL; 3070 atomic_set(&bs->copy_on_read, 0); 3071 bs->backing_file[0] = '\0'; 3072 bs->backing_format[0] = '\0'; 3073 bs->total_sectors = 0; 3074 bs->encrypted = false; 3075 bs->valid_key = false; 3076 bs->sg = false; 3077 QDECREF(bs->options); 3078 QDECREF(bs->explicit_options); 3079 bs->options = NULL; 3080 QDECREF(bs->full_open_options); 3081 bs->full_open_options = NULL; 3082 } 3083 3084 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { 3085 g_free(ban); 3086 } 3087 QLIST_INIT(&bs->aio_notifiers); 3088 bdrv_drained_end(bs); 3089 } 3090 3091 void bdrv_close_all(void) 3092 { 3093 block_job_cancel_sync_all(); 3094 nbd_export_close_all(); 3095 3096 /* Drop references from requests still in flight, such as canceled block 3097 * jobs whose AIO context has not been polled yet */ 3098 bdrv_drain_all(); 3099 3100 blk_remove_all_bs(); 3101 blockdev_close_all_bdrv_states(); 3102 3103 assert(QTAILQ_EMPTY(&all_bdrv_states)); 3104 } 3105 3106 static bool should_update_child(BdrvChild *c, BlockDriverState *to) 3107 { 3108 BdrvChild *to_c; 3109 3110 if (c->role->stay_at_node) { 3111 return false; 3112 } 3113 3114 if (c->role == &child_backing) { 3115 /* If @from is a backing file of @to, ignore the child to avoid 3116 * creating a loop. We only want to change the pointer of other 3117 * parents. */ 3118 QLIST_FOREACH(to_c, &to->children, next) { 3119 if (to_c == c) { 3120 break; 3121 } 3122 } 3123 if (to_c) { 3124 return false; 3125 } 3126 } 3127 3128 return true; 3129 } 3130 3131 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, 3132 Error **errp) 3133 { 3134 BdrvChild *c, *next; 3135 GSList *list = NULL, *p; 3136 uint64_t old_perm, old_shared; 3137 uint64_t perm = 0, shared = BLK_PERM_ALL; 3138 int ret; 3139 3140 assert(!atomic_read(&from->in_flight)); 3141 assert(!atomic_read(&to->in_flight)); 3142 3143 /* Make sure that @from doesn't go away until we have successfully attached 3144 * all of its parents to @to. */ 3145 bdrv_ref(from); 3146 3147 /* Put all parents into @list and calculate their cumulative permissions */ 3148 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { 3149 if (!should_update_child(c, to)) { 3150 continue; 3151 } 3152 list = g_slist_prepend(list, c); 3153 perm |= c->perm; 3154 shared &= c->shared_perm; 3155 } 3156 3157 /* Check whether the required permissions can be granted on @to, ignoring 3158 * all BdrvChild in @list so that they can't block themselves. */ 3159 ret = bdrv_check_update_perm(to, perm, shared, list, errp); 3160 if (ret < 0) { 3161 bdrv_abort_perm_update(to); 3162 goto out; 3163 } 3164 3165 /* Now actually perform the change. We performed the permission check for 3166 * all elements of @list at once, so set the permissions all at once at the 3167 * very end. */ 3168 for (p = list; p != NULL; p = p->next) { 3169 c = p->data; 3170 3171 bdrv_ref(to); 3172 bdrv_replace_child_noperm(c, to); 3173 bdrv_unref(from); 3174 } 3175 3176 bdrv_get_cumulative_perm(to, &old_perm, &old_shared); 3177 bdrv_set_perm(to, old_perm | perm, old_shared | shared); 3178 3179 out: 3180 g_slist_free(list); 3181 bdrv_unref(from); 3182 } 3183 3184 /* 3185 * Add new bs contents at the top of an image chain while the chain is 3186 * live, while keeping required fields on the top layer. 3187 * 3188 * This will modify the BlockDriverState fields, and swap contents 3189 * between bs_new and bs_top. Both bs_new and bs_top are modified. 3190 * 3191 * bs_new must not be attached to a BlockBackend. 3192 * 3193 * This function does not create any image files. 3194 * 3195 * bdrv_append() takes ownership of a bs_new reference and unrefs it because 3196 * that's what the callers commonly need. bs_new will be referenced by the old 3197 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a 3198 * reference of its own, it must call bdrv_ref(). 3199 */ 3200 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, 3201 Error **errp) 3202 { 3203 Error *local_err = NULL; 3204 3205 bdrv_set_backing_hd(bs_new, bs_top, &local_err); 3206 if (local_err) { 3207 error_propagate(errp, local_err); 3208 goto out; 3209 } 3210 3211 bdrv_replace_node(bs_top, bs_new, &local_err); 3212 if (local_err) { 3213 error_propagate(errp, local_err); 3214 bdrv_set_backing_hd(bs_new, NULL, &error_abort); 3215 goto out; 3216 } 3217 3218 /* bs_new is now referenced by its new parents, we don't need the 3219 * additional reference any more. */ 3220 out: 3221 bdrv_unref(bs_new); 3222 } 3223 3224 static void bdrv_delete(BlockDriverState *bs) 3225 { 3226 assert(!bs->job); 3227 assert(bdrv_op_blocker_is_empty(bs)); 3228 assert(!bs->refcnt); 3229 3230 bdrv_close(bs); 3231 3232 /* remove from list, if necessary */ 3233 if (bs->node_name[0] != '\0') { 3234 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); 3235 } 3236 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list); 3237 3238 g_free(bs); 3239 } 3240 3241 /* 3242 * Run consistency checks on an image 3243 * 3244 * Returns 0 if the check could be completed (it doesn't mean that the image is 3245 * free of errors) or -errno when an internal error occurred. The results of the 3246 * check are stored in res. 3247 */ 3248 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) 3249 { 3250 if (bs->drv == NULL) { 3251 return -ENOMEDIUM; 3252 } 3253 if (bs->drv->bdrv_check == NULL) { 3254 return -ENOTSUP; 3255 } 3256 3257 memset(res, 0, sizeof(*res)); 3258 return bs->drv->bdrv_check(bs, res, fix); 3259 } 3260 3261 /* 3262 * Return values: 3263 * 0 - success 3264 * -EINVAL - backing format specified, but no file 3265 * -ENOSPC - can't update the backing file because no space is left in the 3266 * image file header 3267 * -ENOTSUP - format driver doesn't support changing the backing file 3268 */ 3269 int bdrv_change_backing_file(BlockDriverState *bs, 3270 const char *backing_file, const char *backing_fmt) 3271 { 3272 BlockDriver *drv = bs->drv; 3273 int ret; 3274 3275 /* Backing file format doesn't make sense without a backing file */ 3276 if (backing_fmt && !backing_file) { 3277 return -EINVAL; 3278 } 3279 3280 if (drv->bdrv_change_backing_file != NULL) { 3281 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); 3282 } else { 3283 ret = -ENOTSUP; 3284 } 3285 3286 if (ret == 0) { 3287 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 3288 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 3289 } 3290 return ret; 3291 } 3292 3293 /* 3294 * Finds the image layer in the chain that has 'bs' as its backing file. 3295 * 3296 * active is the current topmost image. 3297 * 3298 * Returns NULL if bs is not found in active's image chain, 3299 * or if active == bs. 3300 * 3301 * Returns the bottommost base image if bs == NULL. 3302 */ 3303 BlockDriverState *bdrv_find_overlay(BlockDriverState *active, 3304 BlockDriverState *bs) 3305 { 3306 while (active && bs != backing_bs(active)) { 3307 active = backing_bs(active); 3308 } 3309 3310 return active; 3311 } 3312 3313 /* Given a BDS, searches for the base layer. */ 3314 BlockDriverState *bdrv_find_base(BlockDriverState *bs) 3315 { 3316 return bdrv_find_overlay(bs, NULL); 3317 } 3318 3319 /* 3320 * Drops images above 'base' up to and including 'top', and sets the image 3321 * above 'top' to have base as its backing file. 3322 * 3323 * Requires that the overlay to 'top' is opened r/w, so that the backing file 3324 * information in 'bs' can be properly updated. 3325 * 3326 * E.g., this will convert the following chain: 3327 * bottom <- base <- intermediate <- top <- active 3328 * 3329 * to 3330 * 3331 * bottom <- base <- active 3332 * 3333 * It is allowed for bottom==base, in which case it converts: 3334 * 3335 * base <- intermediate <- top <- active 3336 * 3337 * to 3338 * 3339 * base <- active 3340 * 3341 * If backing_file_str is non-NULL, it will be used when modifying top's 3342 * overlay image metadata. 3343 * 3344 * Error conditions: 3345 * if active == top, that is considered an error 3346 * 3347 */ 3348 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, 3349 BlockDriverState *base, const char *backing_file_str) 3350 { 3351 BlockDriverState *new_top_bs = NULL; 3352 Error *local_err = NULL; 3353 int ret = -EIO; 3354 3355 if (!top->drv || !base->drv) { 3356 goto exit; 3357 } 3358 3359 new_top_bs = bdrv_find_overlay(active, top); 3360 3361 if (new_top_bs == NULL) { 3362 /* we could not find the image above 'top', this is an error */ 3363 goto exit; 3364 } 3365 3366 /* special case of new_top_bs->backing->bs already pointing to base - nothing 3367 * to do, no intermediate images */ 3368 if (backing_bs(new_top_bs) == base) { 3369 ret = 0; 3370 goto exit; 3371 } 3372 3373 /* Make sure that base is in the backing chain of top */ 3374 if (!bdrv_chain_contains(top, base)) { 3375 goto exit; 3376 } 3377 3378 /* success - we can delete the intermediate states, and link top->base */ 3379 backing_file_str = backing_file_str ? backing_file_str : base->filename; 3380 ret = bdrv_change_backing_file(new_top_bs, backing_file_str, 3381 base->drv ? base->drv->format_name : ""); 3382 if (ret) { 3383 goto exit; 3384 } 3385 3386 bdrv_set_backing_hd(new_top_bs, base, &local_err); 3387 if (local_err) { 3388 ret = -EPERM; 3389 error_report_err(local_err); 3390 goto exit; 3391 } 3392 3393 ret = 0; 3394 exit: 3395 return ret; 3396 } 3397 3398 /** 3399 * Truncate file to 'offset' bytes (needed only for file protocols) 3400 */ 3401 int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp) 3402 { 3403 BlockDriverState *bs = child->bs; 3404 BlockDriver *drv = bs->drv; 3405 int ret; 3406 3407 assert(child->perm & BLK_PERM_RESIZE); 3408 3409 if (!drv) { 3410 error_setg(errp, "No medium inserted"); 3411 return -ENOMEDIUM; 3412 } 3413 if (!drv->bdrv_truncate) { 3414 error_setg(errp, "Image format driver does not support resize"); 3415 return -ENOTSUP; 3416 } 3417 if (bs->read_only) { 3418 error_setg(errp, "Image is read-only"); 3419 return -EACCES; 3420 } 3421 3422 assert(!(bs->open_flags & BDRV_O_INACTIVE)); 3423 3424 ret = drv->bdrv_truncate(bs, offset, errp); 3425 if (ret == 0) { 3426 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); 3427 bdrv_dirty_bitmap_truncate(bs); 3428 bdrv_parent_cb_resize(bs); 3429 atomic_inc(&bs->write_gen); 3430 } 3431 return ret; 3432 } 3433 3434 /** 3435 * Length of a allocated file in bytes. Sparse files are counted by actual 3436 * allocated space. Return < 0 if error or unknown. 3437 */ 3438 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) 3439 { 3440 BlockDriver *drv = bs->drv; 3441 if (!drv) { 3442 return -ENOMEDIUM; 3443 } 3444 if (drv->bdrv_get_allocated_file_size) { 3445 return drv->bdrv_get_allocated_file_size(bs); 3446 } 3447 if (bs->file) { 3448 return bdrv_get_allocated_file_size(bs->file->bs); 3449 } 3450 return -ENOTSUP; 3451 } 3452 3453 /** 3454 * Return number of sectors on success, -errno on error. 3455 */ 3456 int64_t bdrv_nb_sectors(BlockDriverState *bs) 3457 { 3458 BlockDriver *drv = bs->drv; 3459 3460 if (!drv) 3461 return -ENOMEDIUM; 3462 3463 if (drv->has_variable_length) { 3464 int ret = refresh_total_sectors(bs, bs->total_sectors); 3465 if (ret < 0) { 3466 return ret; 3467 } 3468 } 3469 return bs->total_sectors; 3470 } 3471 3472 /** 3473 * Return length in bytes on success, -errno on error. 3474 * The length is always a multiple of BDRV_SECTOR_SIZE. 3475 */ 3476 int64_t bdrv_getlength(BlockDriverState *bs) 3477 { 3478 int64_t ret = bdrv_nb_sectors(bs); 3479 3480 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret; 3481 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE; 3482 } 3483 3484 /* return 0 as number of sectors if no device present or error */ 3485 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) 3486 { 3487 int64_t nb_sectors = bdrv_nb_sectors(bs); 3488 3489 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors; 3490 } 3491 3492 bool bdrv_is_sg(BlockDriverState *bs) 3493 { 3494 return bs->sg; 3495 } 3496 3497 bool bdrv_is_encrypted(BlockDriverState *bs) 3498 { 3499 if (bs->backing && bs->backing->bs->encrypted) { 3500 return true; 3501 } 3502 return bs->encrypted; 3503 } 3504 3505 bool bdrv_key_required(BlockDriverState *bs) 3506 { 3507 BdrvChild *backing = bs->backing; 3508 3509 if (backing && backing->bs->encrypted && !backing->bs->valid_key) { 3510 return true; 3511 } 3512 return (bs->encrypted && !bs->valid_key); 3513 } 3514 3515 int bdrv_set_key(BlockDriverState *bs, const char *key) 3516 { 3517 int ret; 3518 if (bs->backing && bs->backing->bs->encrypted) { 3519 ret = bdrv_set_key(bs->backing->bs, key); 3520 if (ret < 0) 3521 return ret; 3522 if (!bs->encrypted) 3523 return 0; 3524 } 3525 if (!bs->encrypted) { 3526 return -EINVAL; 3527 } else if (!bs->drv || !bs->drv->bdrv_set_key) { 3528 return -ENOMEDIUM; 3529 } 3530 ret = bs->drv->bdrv_set_key(bs, key); 3531 if (ret < 0) { 3532 bs->valid_key = false; 3533 } else if (!bs->valid_key) { 3534 /* call the change callback now, we skipped it on open */ 3535 bs->valid_key = true; 3536 bdrv_parent_cb_change_media(bs, true); 3537 } 3538 return ret; 3539 } 3540 3541 /* 3542 * Provide an encryption key for @bs. 3543 * If @key is non-null: 3544 * If @bs is not encrypted, fail. 3545 * Else if the key is invalid, fail. 3546 * Else set @bs's key to @key, replacing the existing key, if any. 3547 * If @key is null: 3548 * If @bs is encrypted and still lacks a key, fail. 3549 * Else do nothing. 3550 * On failure, store an error object through @errp if non-null. 3551 */ 3552 void bdrv_add_key(BlockDriverState *bs, const char *key, Error **errp) 3553 { 3554 if (key) { 3555 if (!bdrv_is_encrypted(bs)) { 3556 error_setg(errp, "Node '%s' is not encrypted", 3557 bdrv_get_device_or_node_name(bs)); 3558 } else if (bdrv_set_key(bs, key) < 0) { 3559 error_setg(errp, QERR_INVALID_PASSWORD); 3560 } 3561 } else { 3562 if (bdrv_key_required(bs)) { 3563 error_set(errp, ERROR_CLASS_DEVICE_ENCRYPTED, 3564 "'%s' (%s) is encrypted", 3565 bdrv_get_device_or_node_name(bs), 3566 bdrv_get_encrypted_filename(bs)); 3567 } 3568 } 3569 } 3570 3571 const char *bdrv_get_format_name(BlockDriverState *bs) 3572 { 3573 return bs->drv ? bs->drv->format_name : NULL; 3574 } 3575 3576 static int qsort_strcmp(const void *a, const void *b) 3577 { 3578 return strcmp(*(char *const *)a, *(char *const *)b); 3579 } 3580 3581 void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 3582 void *opaque) 3583 { 3584 BlockDriver *drv; 3585 int count = 0; 3586 int i; 3587 const char **formats = NULL; 3588 3589 QLIST_FOREACH(drv, &bdrv_drivers, list) { 3590 if (drv->format_name) { 3591 bool found = false; 3592 int i = count; 3593 while (formats && i && !found) { 3594 found = !strcmp(formats[--i], drv->format_name); 3595 } 3596 3597 if (!found) { 3598 formats = g_renew(const char *, formats, count + 1); 3599 formats[count++] = drv->format_name; 3600 } 3601 } 3602 } 3603 3604 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) { 3605 const char *format_name = block_driver_modules[i].format_name; 3606 3607 if (format_name) { 3608 bool found = false; 3609 int j = count; 3610 3611 while (formats && j && !found) { 3612 found = !strcmp(formats[--j], format_name); 3613 } 3614 3615 if (!found) { 3616 formats = g_renew(const char *, formats, count + 1); 3617 formats[count++] = format_name; 3618 } 3619 } 3620 } 3621 3622 qsort(formats, count, sizeof(formats[0]), qsort_strcmp); 3623 3624 for (i = 0; i < count; i++) { 3625 it(opaque, formats[i]); 3626 } 3627 3628 g_free(formats); 3629 } 3630 3631 /* This function is to find a node in the bs graph */ 3632 BlockDriverState *bdrv_find_node(const char *node_name) 3633 { 3634 BlockDriverState *bs; 3635 3636 assert(node_name); 3637 3638 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3639 if (!strcmp(node_name, bs->node_name)) { 3640 return bs; 3641 } 3642 } 3643 return NULL; 3644 } 3645 3646 /* Put this QMP function here so it can access the static graph_bdrv_states. */ 3647 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp) 3648 { 3649 BlockDeviceInfoList *list, *entry; 3650 BlockDriverState *bs; 3651 3652 list = NULL; 3653 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3654 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp); 3655 if (!info) { 3656 qapi_free_BlockDeviceInfoList(list); 3657 return NULL; 3658 } 3659 entry = g_malloc0(sizeof(*entry)); 3660 entry->value = info; 3661 entry->next = list; 3662 list = entry; 3663 } 3664 3665 return list; 3666 } 3667 3668 BlockDriverState *bdrv_lookup_bs(const char *device, 3669 const char *node_name, 3670 Error **errp) 3671 { 3672 BlockBackend *blk; 3673 BlockDriverState *bs; 3674 3675 if (device) { 3676 blk = blk_by_name(device); 3677 3678 if (blk) { 3679 bs = blk_bs(blk); 3680 if (!bs) { 3681 error_setg(errp, "Device '%s' has no medium", device); 3682 } 3683 3684 return bs; 3685 } 3686 } 3687 3688 if (node_name) { 3689 bs = bdrv_find_node(node_name); 3690 3691 if (bs) { 3692 return bs; 3693 } 3694 } 3695 3696 error_setg(errp, "Cannot find device=%s nor node_name=%s", 3697 device ? device : "", 3698 node_name ? node_name : ""); 3699 return NULL; 3700 } 3701 3702 /* If 'base' is in the same chain as 'top', return true. Otherwise, 3703 * return false. If either argument is NULL, return false. */ 3704 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) 3705 { 3706 while (top && top != base) { 3707 top = backing_bs(top); 3708 } 3709 3710 return top != NULL; 3711 } 3712 3713 BlockDriverState *bdrv_next_node(BlockDriverState *bs) 3714 { 3715 if (!bs) { 3716 return QTAILQ_FIRST(&graph_bdrv_states); 3717 } 3718 return QTAILQ_NEXT(bs, node_list); 3719 } 3720 3721 const char *bdrv_get_node_name(const BlockDriverState *bs) 3722 { 3723 return bs->node_name; 3724 } 3725 3726 const char *bdrv_get_parent_name(const BlockDriverState *bs) 3727 { 3728 BdrvChild *c; 3729 const char *name; 3730 3731 /* If multiple parents have a name, just pick the first one. */ 3732 QLIST_FOREACH(c, &bs->parents, next_parent) { 3733 if (c->role->get_name) { 3734 name = c->role->get_name(c); 3735 if (name && *name) { 3736 return name; 3737 } 3738 } 3739 } 3740 3741 return NULL; 3742 } 3743 3744 /* TODO check what callers really want: bs->node_name or blk_name() */ 3745 const char *bdrv_get_device_name(const BlockDriverState *bs) 3746 { 3747 return bdrv_get_parent_name(bs) ?: ""; 3748 } 3749 3750 /* This can be used to identify nodes that might not have a device 3751 * name associated. Since node and device names live in the same 3752 * namespace, the result is unambiguous. The exception is if both are 3753 * absent, then this returns an empty (non-null) string. */ 3754 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs) 3755 { 3756 return bdrv_get_parent_name(bs) ?: bs->node_name; 3757 } 3758 3759 int bdrv_get_flags(BlockDriverState *bs) 3760 { 3761 return bs->open_flags; 3762 } 3763 3764 int bdrv_has_zero_init_1(BlockDriverState *bs) 3765 { 3766 return 1; 3767 } 3768 3769 int bdrv_has_zero_init(BlockDriverState *bs) 3770 { 3771 assert(bs->drv); 3772 3773 /* If BS is a copy on write image, it is initialized to 3774 the contents of the base image, which may not be zeroes. */ 3775 if (bs->backing) { 3776 return 0; 3777 } 3778 if (bs->drv->bdrv_has_zero_init) { 3779 return bs->drv->bdrv_has_zero_init(bs); 3780 } 3781 3782 /* safe default */ 3783 return 0; 3784 } 3785 3786 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) 3787 { 3788 BlockDriverInfo bdi; 3789 3790 if (bs->backing) { 3791 return false; 3792 } 3793 3794 if (bdrv_get_info(bs, &bdi) == 0) { 3795 return bdi.unallocated_blocks_are_zero; 3796 } 3797 3798 return false; 3799 } 3800 3801 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) 3802 { 3803 BlockDriverInfo bdi; 3804 3805 if (!(bs->open_flags & BDRV_O_UNMAP)) { 3806 return false; 3807 } 3808 3809 if (bdrv_get_info(bs, &bdi) == 0) { 3810 return bdi.can_write_zeroes_with_unmap; 3811 } 3812 3813 return false; 3814 } 3815 3816 const char *bdrv_get_encrypted_filename(BlockDriverState *bs) 3817 { 3818 if (bs->backing && bs->backing->bs->encrypted) 3819 return bs->backing_file; 3820 else if (bs->encrypted) 3821 return bs->filename; 3822 else 3823 return NULL; 3824 } 3825 3826 void bdrv_get_backing_filename(BlockDriverState *bs, 3827 char *filename, int filename_size) 3828 { 3829 pstrcpy(filename, filename_size, bs->backing_file); 3830 } 3831 3832 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3833 { 3834 BlockDriver *drv = bs->drv; 3835 if (!drv) 3836 return -ENOMEDIUM; 3837 if (!drv->bdrv_get_info) 3838 return -ENOTSUP; 3839 memset(bdi, 0, sizeof(*bdi)); 3840 return drv->bdrv_get_info(bs, bdi); 3841 } 3842 3843 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) 3844 { 3845 BlockDriver *drv = bs->drv; 3846 if (drv && drv->bdrv_get_specific_info) { 3847 return drv->bdrv_get_specific_info(bs); 3848 } 3849 return NULL; 3850 } 3851 3852 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event) 3853 { 3854 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { 3855 return; 3856 } 3857 3858 bs->drv->bdrv_debug_event(bs, event); 3859 } 3860 3861 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, 3862 const char *tag) 3863 { 3864 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { 3865 bs = bs->file ? bs->file->bs : NULL; 3866 } 3867 3868 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { 3869 return bs->drv->bdrv_debug_breakpoint(bs, event, tag); 3870 } 3871 3872 return -ENOTSUP; 3873 } 3874 3875 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) 3876 { 3877 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { 3878 bs = bs->file ? bs->file->bs : NULL; 3879 } 3880 3881 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { 3882 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); 3883 } 3884 3885 return -ENOTSUP; 3886 } 3887 3888 int bdrv_debug_resume(BlockDriverState *bs, const char *tag) 3889 { 3890 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) { 3891 bs = bs->file ? bs->file->bs : NULL; 3892 } 3893 3894 if (bs && bs->drv && bs->drv->bdrv_debug_resume) { 3895 return bs->drv->bdrv_debug_resume(bs, tag); 3896 } 3897 3898 return -ENOTSUP; 3899 } 3900 3901 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) 3902 { 3903 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { 3904 bs = bs->file ? bs->file->bs : NULL; 3905 } 3906 3907 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { 3908 return bs->drv->bdrv_debug_is_suspended(bs, tag); 3909 } 3910 3911 return false; 3912 } 3913 3914 /* backing_file can either be relative, or absolute, or a protocol. If it is 3915 * relative, it must be relative to the chain. So, passing in bs->filename 3916 * from a BDS as backing_file should not be done, as that may be relative to 3917 * the CWD rather than the chain. */ 3918 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 3919 const char *backing_file) 3920 { 3921 char *filename_full = NULL; 3922 char *backing_file_full = NULL; 3923 char *filename_tmp = NULL; 3924 int is_protocol = 0; 3925 BlockDriverState *curr_bs = NULL; 3926 BlockDriverState *retval = NULL; 3927 Error *local_error = NULL; 3928 3929 if (!bs || !bs->drv || !backing_file) { 3930 return NULL; 3931 } 3932 3933 filename_full = g_malloc(PATH_MAX); 3934 backing_file_full = g_malloc(PATH_MAX); 3935 filename_tmp = g_malloc(PATH_MAX); 3936 3937 is_protocol = path_has_protocol(backing_file); 3938 3939 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) { 3940 3941 /* If either of the filename paths is actually a protocol, then 3942 * compare unmodified paths; otherwise make paths relative */ 3943 if (is_protocol || path_has_protocol(curr_bs->backing_file)) { 3944 if (strcmp(backing_file, curr_bs->backing_file) == 0) { 3945 retval = curr_bs->backing->bs; 3946 break; 3947 } 3948 /* Also check against the full backing filename for the image */ 3949 bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX, 3950 &local_error); 3951 if (local_error == NULL) { 3952 if (strcmp(backing_file, backing_file_full) == 0) { 3953 retval = curr_bs->backing->bs; 3954 break; 3955 } 3956 } else { 3957 error_free(local_error); 3958 local_error = NULL; 3959 } 3960 } else { 3961 /* If not an absolute filename path, make it relative to the current 3962 * image's filename path */ 3963 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3964 backing_file); 3965 3966 /* We are going to compare absolute pathnames */ 3967 if (!realpath(filename_tmp, filename_full)) { 3968 continue; 3969 } 3970 3971 /* We need to make sure the backing filename we are comparing against 3972 * is relative to the current image filename (or absolute) */ 3973 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3974 curr_bs->backing_file); 3975 3976 if (!realpath(filename_tmp, backing_file_full)) { 3977 continue; 3978 } 3979 3980 if (strcmp(backing_file_full, filename_full) == 0) { 3981 retval = curr_bs->backing->bs; 3982 break; 3983 } 3984 } 3985 } 3986 3987 g_free(filename_full); 3988 g_free(backing_file_full); 3989 g_free(filename_tmp); 3990 return retval; 3991 } 3992 3993 int bdrv_get_backing_file_depth(BlockDriverState *bs) 3994 { 3995 if (!bs->drv) { 3996 return 0; 3997 } 3998 3999 if (!bs->backing) { 4000 return 0; 4001 } 4002 4003 return 1 + bdrv_get_backing_file_depth(bs->backing->bs); 4004 } 4005 4006 void bdrv_init(void) 4007 { 4008 module_call_init(MODULE_INIT_BLOCK); 4009 } 4010 4011 void bdrv_init_with_whitelist(void) 4012 { 4013 use_bdrv_whitelist = 1; 4014 bdrv_init(); 4015 } 4016 4017 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) 4018 { 4019 BdrvChild *child, *parent; 4020 uint64_t perm, shared_perm; 4021 Error *local_err = NULL; 4022 int ret; 4023 4024 if (!bs->drv) { 4025 return; 4026 } 4027 4028 if (!(bs->open_flags & BDRV_O_INACTIVE)) { 4029 return; 4030 } 4031 4032 QLIST_FOREACH(child, &bs->children, next) { 4033 bdrv_invalidate_cache(child->bs, &local_err); 4034 if (local_err) { 4035 error_propagate(errp, local_err); 4036 return; 4037 } 4038 } 4039 4040 bs->open_flags &= ~BDRV_O_INACTIVE; 4041 if (bs->drv->bdrv_invalidate_cache) { 4042 bs->drv->bdrv_invalidate_cache(bs, &local_err); 4043 if (local_err) { 4044 bs->open_flags |= BDRV_O_INACTIVE; 4045 error_propagate(errp, local_err); 4046 return; 4047 } 4048 } 4049 4050 ret = refresh_total_sectors(bs, bs->total_sectors); 4051 if (ret < 0) { 4052 bs->open_flags |= BDRV_O_INACTIVE; 4053 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 4054 return; 4055 } 4056 4057 /* Update permissions, they may differ for inactive nodes */ 4058 bdrv_get_cumulative_perm(bs, &perm, &shared_perm); 4059 ret = bdrv_check_perm(bs, perm, shared_perm, NULL, &local_err); 4060 if (ret < 0) { 4061 bs->open_flags |= BDRV_O_INACTIVE; 4062 error_propagate(errp, local_err); 4063 return; 4064 } 4065 bdrv_set_perm(bs, perm, shared_perm); 4066 4067 QLIST_FOREACH(parent, &bs->parents, next_parent) { 4068 if (parent->role->activate) { 4069 parent->role->activate(parent, &local_err); 4070 if (local_err) { 4071 error_propagate(errp, local_err); 4072 return; 4073 } 4074 } 4075 } 4076 } 4077 4078 void bdrv_invalidate_cache_all(Error **errp) 4079 { 4080 BlockDriverState *bs; 4081 Error *local_err = NULL; 4082 BdrvNextIterator it; 4083 4084 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4085 AioContext *aio_context = bdrv_get_aio_context(bs); 4086 4087 aio_context_acquire(aio_context); 4088 bdrv_invalidate_cache(bs, &local_err); 4089 aio_context_release(aio_context); 4090 if (local_err) { 4091 error_propagate(errp, local_err); 4092 return; 4093 } 4094 } 4095 } 4096 4097 static int bdrv_inactivate_recurse(BlockDriverState *bs, 4098 bool setting_flag) 4099 { 4100 BdrvChild *child, *parent; 4101 int ret; 4102 4103 if (!setting_flag && bs->drv->bdrv_inactivate) { 4104 ret = bs->drv->bdrv_inactivate(bs); 4105 if (ret < 0) { 4106 return ret; 4107 } 4108 } 4109 4110 if (setting_flag) { 4111 uint64_t perm, shared_perm; 4112 4113 bs->open_flags |= BDRV_O_INACTIVE; 4114 4115 QLIST_FOREACH(parent, &bs->parents, next_parent) { 4116 if (parent->role->inactivate) { 4117 ret = parent->role->inactivate(parent); 4118 if (ret < 0) { 4119 bs->open_flags &= ~BDRV_O_INACTIVE; 4120 return ret; 4121 } 4122 } 4123 } 4124 4125 /* Update permissions, they may differ for inactive nodes */ 4126 bdrv_get_cumulative_perm(bs, &perm, &shared_perm); 4127 bdrv_check_perm(bs, perm, shared_perm, NULL, &error_abort); 4128 bdrv_set_perm(bs, perm, shared_perm); 4129 } 4130 4131 QLIST_FOREACH(child, &bs->children, next) { 4132 ret = bdrv_inactivate_recurse(child->bs, setting_flag); 4133 if (ret < 0) { 4134 return ret; 4135 } 4136 } 4137 4138 return 0; 4139 } 4140 4141 int bdrv_inactivate_all(void) 4142 { 4143 BlockDriverState *bs = NULL; 4144 BdrvNextIterator it; 4145 int ret = 0; 4146 int pass; 4147 4148 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4149 aio_context_acquire(bdrv_get_aio_context(bs)); 4150 } 4151 4152 /* We do two passes of inactivation. The first pass calls to drivers' 4153 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk; 4154 * the second pass sets the BDRV_O_INACTIVE flag so that no further write 4155 * is allowed. */ 4156 for (pass = 0; pass < 2; pass++) { 4157 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4158 ret = bdrv_inactivate_recurse(bs, pass); 4159 if (ret < 0) { 4160 goto out; 4161 } 4162 } 4163 } 4164 4165 out: 4166 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4167 aio_context_release(bdrv_get_aio_context(bs)); 4168 } 4169 4170 return ret; 4171 } 4172 4173 /**************************************************************/ 4174 /* removable device support */ 4175 4176 /** 4177 * Return TRUE if the media is present 4178 */ 4179 bool bdrv_is_inserted(BlockDriverState *bs) 4180 { 4181 BlockDriver *drv = bs->drv; 4182 BdrvChild *child; 4183 4184 if (!drv) { 4185 return false; 4186 } 4187 if (drv->bdrv_is_inserted) { 4188 return drv->bdrv_is_inserted(bs); 4189 } 4190 QLIST_FOREACH(child, &bs->children, next) { 4191 if (!bdrv_is_inserted(child->bs)) { 4192 return false; 4193 } 4194 } 4195 return true; 4196 } 4197 4198 /** 4199 * Return whether the media changed since the last call to this 4200 * function, or -ENOTSUP if we don't know. Most drivers don't know. 4201 */ 4202 int bdrv_media_changed(BlockDriverState *bs) 4203 { 4204 BlockDriver *drv = bs->drv; 4205 4206 if (drv && drv->bdrv_media_changed) { 4207 return drv->bdrv_media_changed(bs); 4208 } 4209 return -ENOTSUP; 4210 } 4211 4212 /** 4213 * If eject_flag is TRUE, eject the media. Otherwise, close the tray 4214 */ 4215 void bdrv_eject(BlockDriverState *bs, bool eject_flag) 4216 { 4217 BlockDriver *drv = bs->drv; 4218 4219 if (drv && drv->bdrv_eject) { 4220 drv->bdrv_eject(bs, eject_flag); 4221 } 4222 } 4223 4224 /** 4225 * Lock or unlock the media (if it is locked, the user won't be able 4226 * to eject it manually). 4227 */ 4228 void bdrv_lock_medium(BlockDriverState *bs, bool locked) 4229 { 4230 BlockDriver *drv = bs->drv; 4231 4232 trace_bdrv_lock_medium(bs, locked); 4233 4234 if (drv && drv->bdrv_lock_medium) { 4235 drv->bdrv_lock_medium(bs, locked); 4236 } 4237 } 4238 4239 /* Get a reference to bs */ 4240 void bdrv_ref(BlockDriverState *bs) 4241 { 4242 bs->refcnt++; 4243 } 4244 4245 /* Release a previously grabbed reference to bs. 4246 * If after releasing, reference count is zero, the BlockDriverState is 4247 * deleted. */ 4248 void bdrv_unref(BlockDriverState *bs) 4249 { 4250 if (!bs) { 4251 return; 4252 } 4253 assert(bs->refcnt > 0); 4254 if (--bs->refcnt == 0) { 4255 bdrv_delete(bs); 4256 } 4257 } 4258 4259 struct BdrvOpBlocker { 4260 Error *reason; 4261 QLIST_ENTRY(BdrvOpBlocker) list; 4262 }; 4263 4264 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) 4265 { 4266 BdrvOpBlocker *blocker; 4267 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); 4268 if (!QLIST_EMPTY(&bs->op_blockers[op])) { 4269 blocker = QLIST_FIRST(&bs->op_blockers[op]); 4270 if (errp) { 4271 *errp = error_copy(blocker->reason); 4272 error_prepend(errp, "Node '%s' is busy: ", 4273 bdrv_get_device_or_node_name(bs)); 4274 } 4275 return true; 4276 } 4277 return false; 4278 } 4279 4280 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason) 4281 { 4282 BdrvOpBlocker *blocker; 4283 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); 4284 4285 blocker = g_new0(BdrvOpBlocker, 1); 4286 blocker->reason = reason; 4287 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list); 4288 } 4289 4290 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason) 4291 { 4292 BdrvOpBlocker *blocker, *next; 4293 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); 4294 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) { 4295 if (blocker->reason == reason) { 4296 QLIST_REMOVE(blocker, list); 4297 g_free(blocker); 4298 } 4299 } 4300 } 4301 4302 void bdrv_op_block_all(BlockDriverState *bs, Error *reason) 4303 { 4304 int i; 4305 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 4306 bdrv_op_block(bs, i, reason); 4307 } 4308 } 4309 4310 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason) 4311 { 4312 int i; 4313 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 4314 bdrv_op_unblock(bs, i, reason); 4315 } 4316 } 4317 4318 bool bdrv_op_blocker_is_empty(BlockDriverState *bs) 4319 { 4320 int i; 4321 4322 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 4323 if (!QLIST_EMPTY(&bs->op_blockers[i])) { 4324 return false; 4325 } 4326 } 4327 return true; 4328 } 4329 4330 void bdrv_img_create(const char *filename, const char *fmt, 4331 const char *base_filename, const char *base_fmt, 4332 char *options, uint64_t img_size, int flags, bool quiet, 4333 Error **errp) 4334 { 4335 QemuOptsList *create_opts = NULL; 4336 QemuOpts *opts = NULL; 4337 const char *backing_fmt, *backing_file; 4338 int64_t size; 4339 BlockDriver *drv, *proto_drv; 4340 Error *local_err = NULL; 4341 int ret = 0; 4342 4343 /* Find driver and parse its options */ 4344 drv = bdrv_find_format(fmt); 4345 if (!drv) { 4346 error_setg(errp, "Unknown file format '%s'", fmt); 4347 return; 4348 } 4349 4350 proto_drv = bdrv_find_protocol(filename, true, errp); 4351 if (!proto_drv) { 4352 return; 4353 } 4354 4355 if (!drv->create_opts) { 4356 error_setg(errp, "Format driver '%s' does not support image creation", 4357 drv->format_name); 4358 return; 4359 } 4360 4361 if (!proto_drv->create_opts) { 4362 error_setg(errp, "Protocol driver '%s' does not support image creation", 4363 proto_drv->format_name); 4364 return; 4365 } 4366 4367 create_opts = qemu_opts_append(create_opts, drv->create_opts); 4368 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts); 4369 4370 /* Create parameter list with default values */ 4371 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort); 4372 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort); 4373 4374 /* Parse -o options */ 4375 if (options) { 4376 qemu_opts_do_parse(opts, options, NULL, &local_err); 4377 if (local_err) { 4378 error_report_err(local_err); 4379 local_err = NULL; 4380 error_setg(errp, "Invalid options for file format '%s'", fmt); 4381 goto out; 4382 } 4383 } 4384 4385 if (base_filename) { 4386 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err); 4387 if (local_err) { 4388 error_setg(errp, "Backing file not supported for file format '%s'", 4389 fmt); 4390 goto out; 4391 } 4392 } 4393 4394 if (base_fmt) { 4395 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err); 4396 if (local_err) { 4397 error_setg(errp, "Backing file format not supported for file " 4398 "format '%s'", fmt); 4399 goto out; 4400 } 4401 } 4402 4403 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4404 if (backing_file) { 4405 if (!strcmp(filename, backing_file)) { 4406 error_setg(errp, "Error: Trying to create an image with the " 4407 "same filename as the backing file"); 4408 goto out; 4409 } 4410 } 4411 4412 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4413 4414 // The size for the image must always be specified, with one exception: 4415 // If we are using a backing file, we can obtain the size from there 4416 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 4417 if (size == -1) { 4418 if (backing_file) { 4419 BlockDriverState *bs; 4420 char *full_backing = g_new0(char, PATH_MAX); 4421 int64_t size; 4422 int back_flags; 4423 QDict *backing_options = NULL; 4424 4425 bdrv_get_full_backing_filename_from_filename(filename, backing_file, 4426 full_backing, PATH_MAX, 4427 &local_err); 4428 if (local_err) { 4429 g_free(full_backing); 4430 goto out; 4431 } 4432 4433 /* backing files always opened read-only */ 4434 back_flags = flags; 4435 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 4436 4437 if (backing_fmt) { 4438 backing_options = qdict_new(); 4439 qdict_put_str(backing_options, "driver", backing_fmt); 4440 } 4441 4442 bs = bdrv_open(full_backing, NULL, backing_options, back_flags, 4443 &local_err); 4444 g_free(full_backing); 4445 if (!bs) { 4446 goto out; 4447 } 4448 size = bdrv_getlength(bs); 4449 if (size < 0) { 4450 error_setg_errno(errp, -size, "Could not get size of '%s'", 4451 backing_file); 4452 bdrv_unref(bs); 4453 goto out; 4454 } 4455 4456 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort); 4457 4458 bdrv_unref(bs); 4459 } else { 4460 error_setg(errp, "Image creation needs a size parameter"); 4461 goto out; 4462 } 4463 } 4464 4465 if (!quiet) { 4466 printf("Formatting '%s', fmt=%s ", filename, fmt); 4467 qemu_opts_print(opts, " "); 4468 puts(""); 4469 } 4470 4471 ret = bdrv_create(drv, filename, opts, &local_err); 4472 4473 if (ret == -EFBIG) { 4474 /* This is generally a better message than whatever the driver would 4475 * deliver (especially because of the cluster_size_hint), since that 4476 * is most probably not much different from "image too large". */ 4477 const char *cluster_size_hint = ""; 4478 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) { 4479 cluster_size_hint = " (try using a larger cluster size)"; 4480 } 4481 error_setg(errp, "The image size is too large for file format '%s'" 4482 "%s", fmt, cluster_size_hint); 4483 error_free(local_err); 4484 local_err = NULL; 4485 } 4486 4487 out: 4488 qemu_opts_del(opts); 4489 qemu_opts_free(create_opts); 4490 error_propagate(errp, local_err); 4491 } 4492 4493 AioContext *bdrv_get_aio_context(BlockDriverState *bs) 4494 { 4495 return bs->aio_context; 4496 } 4497 4498 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co) 4499 { 4500 aio_co_enter(bdrv_get_aio_context(bs), co); 4501 } 4502 4503 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban) 4504 { 4505 QLIST_REMOVE(ban, list); 4506 g_free(ban); 4507 } 4508 4509 void bdrv_detach_aio_context(BlockDriverState *bs) 4510 { 4511 BdrvAioNotifier *baf, *baf_tmp; 4512 BdrvChild *child; 4513 4514 if (!bs->drv) { 4515 return; 4516 } 4517 4518 assert(!bs->walking_aio_notifiers); 4519 bs->walking_aio_notifiers = true; 4520 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) { 4521 if (baf->deleted) { 4522 bdrv_do_remove_aio_context_notifier(baf); 4523 } else { 4524 baf->detach_aio_context(baf->opaque); 4525 } 4526 } 4527 /* Never mind iterating again to check for ->deleted. bdrv_close() will 4528 * remove remaining aio notifiers if we aren't called again. 4529 */ 4530 bs->walking_aio_notifiers = false; 4531 4532 if (bs->drv->bdrv_detach_aio_context) { 4533 bs->drv->bdrv_detach_aio_context(bs); 4534 } 4535 QLIST_FOREACH(child, &bs->children, next) { 4536 bdrv_detach_aio_context(child->bs); 4537 } 4538 4539 bs->aio_context = NULL; 4540 } 4541 4542 void bdrv_attach_aio_context(BlockDriverState *bs, 4543 AioContext *new_context) 4544 { 4545 BdrvAioNotifier *ban, *ban_tmp; 4546 BdrvChild *child; 4547 4548 if (!bs->drv) { 4549 return; 4550 } 4551 4552 bs->aio_context = new_context; 4553 4554 QLIST_FOREACH(child, &bs->children, next) { 4555 bdrv_attach_aio_context(child->bs, new_context); 4556 } 4557 if (bs->drv->bdrv_attach_aio_context) { 4558 bs->drv->bdrv_attach_aio_context(bs, new_context); 4559 } 4560 4561 assert(!bs->walking_aio_notifiers); 4562 bs->walking_aio_notifiers = true; 4563 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) { 4564 if (ban->deleted) { 4565 bdrv_do_remove_aio_context_notifier(ban); 4566 } else { 4567 ban->attached_aio_context(new_context, ban->opaque); 4568 } 4569 } 4570 bs->walking_aio_notifiers = false; 4571 } 4572 4573 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) 4574 { 4575 AioContext *ctx = bdrv_get_aio_context(bs); 4576 4577 aio_disable_external(ctx); 4578 bdrv_parent_drained_begin(bs); 4579 bdrv_drain(bs); /* ensure there are no in-flight requests */ 4580 4581 while (aio_poll(ctx, false)) { 4582 /* wait for all bottom halves to execute */ 4583 } 4584 4585 bdrv_detach_aio_context(bs); 4586 4587 /* This function executes in the old AioContext so acquire the new one in 4588 * case it runs in a different thread. 4589 */ 4590 aio_context_acquire(new_context); 4591 bdrv_attach_aio_context(bs, new_context); 4592 bdrv_parent_drained_end(bs); 4593 aio_enable_external(ctx); 4594 aio_context_release(new_context); 4595 } 4596 4597 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 4598 void (*attached_aio_context)(AioContext *new_context, void *opaque), 4599 void (*detach_aio_context)(void *opaque), void *opaque) 4600 { 4601 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1); 4602 *ban = (BdrvAioNotifier){ 4603 .attached_aio_context = attached_aio_context, 4604 .detach_aio_context = detach_aio_context, 4605 .opaque = opaque 4606 }; 4607 4608 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list); 4609 } 4610 4611 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 4612 void (*attached_aio_context)(AioContext *, 4613 void *), 4614 void (*detach_aio_context)(void *), 4615 void *opaque) 4616 { 4617 BdrvAioNotifier *ban, *ban_next; 4618 4619 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { 4620 if (ban->attached_aio_context == attached_aio_context && 4621 ban->detach_aio_context == detach_aio_context && 4622 ban->opaque == opaque && 4623 ban->deleted == false) 4624 { 4625 if (bs->walking_aio_notifiers) { 4626 ban->deleted = true; 4627 } else { 4628 bdrv_do_remove_aio_context_notifier(ban); 4629 } 4630 return; 4631 } 4632 } 4633 4634 abort(); 4635 } 4636 4637 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts, 4638 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 4639 { 4640 if (!bs->drv->bdrv_amend_options) { 4641 return -ENOTSUP; 4642 } 4643 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque); 4644 } 4645 4646 /* This function will be called by the bdrv_recurse_is_first_non_filter method 4647 * of block filter and by bdrv_is_first_non_filter. 4648 * It is used to test if the given bs is the candidate or recurse more in the 4649 * node graph. 4650 */ 4651 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, 4652 BlockDriverState *candidate) 4653 { 4654 /* return false if basic checks fails */ 4655 if (!bs || !bs->drv) { 4656 return false; 4657 } 4658 4659 /* the code reached a non block filter driver -> check if the bs is 4660 * the same as the candidate. It's the recursion termination condition. 4661 */ 4662 if (!bs->drv->is_filter) { 4663 return bs == candidate; 4664 } 4665 /* Down this path the driver is a block filter driver */ 4666 4667 /* If the block filter recursion method is defined use it to recurse down 4668 * the node graph. 4669 */ 4670 if (bs->drv->bdrv_recurse_is_first_non_filter) { 4671 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); 4672 } 4673 4674 /* the driver is a block filter but don't allow to recurse -> return false 4675 */ 4676 return false; 4677 } 4678 4679 /* This function checks if the candidate is the first non filter bs down it's 4680 * bs chain. Since we don't have pointers to parents it explore all bs chains 4681 * from the top. Some filters can choose not to pass down the recursion. 4682 */ 4683 bool bdrv_is_first_non_filter(BlockDriverState *candidate) 4684 { 4685 BlockDriverState *bs; 4686 BdrvNextIterator it; 4687 4688 /* walk down the bs forest recursively */ 4689 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4690 bool perm; 4691 4692 /* try to recurse in this top level bs */ 4693 perm = bdrv_recurse_is_first_non_filter(bs, candidate); 4694 4695 /* candidate is the first non filter */ 4696 if (perm) { 4697 return true; 4698 } 4699 } 4700 4701 return false; 4702 } 4703 4704 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs, 4705 const char *node_name, Error **errp) 4706 { 4707 BlockDriverState *to_replace_bs = bdrv_find_node(node_name); 4708 AioContext *aio_context; 4709 4710 if (!to_replace_bs) { 4711 error_setg(errp, "Node name '%s' not found", node_name); 4712 return NULL; 4713 } 4714 4715 aio_context = bdrv_get_aio_context(to_replace_bs); 4716 aio_context_acquire(aio_context); 4717 4718 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) { 4719 to_replace_bs = NULL; 4720 goto out; 4721 } 4722 4723 /* We don't want arbitrary node of the BDS chain to be replaced only the top 4724 * most non filter in order to prevent data corruption. 4725 * Another benefit is that this tests exclude backing files which are 4726 * blocked by the backing blockers. 4727 */ 4728 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) { 4729 error_setg(errp, "Only top most non filter can be replaced"); 4730 to_replace_bs = NULL; 4731 goto out; 4732 } 4733 4734 out: 4735 aio_context_release(aio_context); 4736 return to_replace_bs; 4737 } 4738 4739 static bool append_open_options(QDict *d, BlockDriverState *bs) 4740 { 4741 const QDictEntry *entry; 4742 QemuOptDesc *desc; 4743 BdrvChild *child; 4744 bool found_any = false; 4745 const char *p; 4746 4747 for (entry = qdict_first(bs->options); entry; 4748 entry = qdict_next(bs->options, entry)) 4749 { 4750 /* Exclude options for children */ 4751 QLIST_FOREACH(child, &bs->children, next) { 4752 if (strstart(qdict_entry_key(entry), child->name, &p) 4753 && (!*p || *p == '.')) 4754 { 4755 break; 4756 } 4757 } 4758 if (child) { 4759 continue; 4760 } 4761 4762 /* And exclude all non-driver-specific options */ 4763 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) { 4764 if (!strcmp(qdict_entry_key(entry), desc->name)) { 4765 break; 4766 } 4767 } 4768 if (desc->name) { 4769 continue; 4770 } 4771 4772 qobject_incref(qdict_entry_value(entry)); 4773 qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry)); 4774 found_any = true; 4775 } 4776 4777 return found_any; 4778 } 4779 4780 /* Updates the following BDS fields: 4781 * - exact_filename: A filename which may be used for opening a block device 4782 * which (mostly) equals the given BDS (even without any 4783 * other options; so reading and writing must return the same 4784 * results, but caching etc. may be different) 4785 * - full_open_options: Options which, when given when opening a block device 4786 * (without a filename), result in a BDS (mostly) 4787 * equalling the given one 4788 * - filename: If exact_filename is set, it is copied here. Otherwise, 4789 * full_open_options is converted to a JSON object, prefixed with 4790 * "json:" (for use through the JSON pseudo protocol) and put here. 4791 */ 4792 void bdrv_refresh_filename(BlockDriverState *bs) 4793 { 4794 BlockDriver *drv = bs->drv; 4795 QDict *opts; 4796 4797 if (!drv) { 4798 return; 4799 } 4800 4801 /* This BDS's file name will most probably depend on its file's name, so 4802 * refresh that first */ 4803 if (bs->file) { 4804 bdrv_refresh_filename(bs->file->bs); 4805 } 4806 4807 if (drv->bdrv_refresh_filename) { 4808 /* Obsolete information is of no use here, so drop the old file name 4809 * information before refreshing it */ 4810 bs->exact_filename[0] = '\0'; 4811 if (bs->full_open_options) { 4812 QDECREF(bs->full_open_options); 4813 bs->full_open_options = NULL; 4814 } 4815 4816 opts = qdict_new(); 4817 append_open_options(opts, bs); 4818 drv->bdrv_refresh_filename(bs, opts); 4819 QDECREF(opts); 4820 } else if (bs->file) { 4821 /* Try to reconstruct valid information from the underlying file */ 4822 bool has_open_options; 4823 4824 bs->exact_filename[0] = '\0'; 4825 if (bs->full_open_options) { 4826 QDECREF(bs->full_open_options); 4827 bs->full_open_options = NULL; 4828 } 4829 4830 opts = qdict_new(); 4831 has_open_options = append_open_options(opts, bs); 4832 4833 /* If no specific options have been given for this BDS, the filename of 4834 * the underlying file should suffice for this one as well */ 4835 if (bs->file->bs->exact_filename[0] && !has_open_options) { 4836 strcpy(bs->exact_filename, bs->file->bs->exact_filename); 4837 } 4838 /* Reconstructing the full options QDict is simple for most format block 4839 * drivers, as long as the full options are known for the underlying 4840 * file BDS. The full options QDict of that file BDS should somehow 4841 * contain a representation of the filename, therefore the following 4842 * suffices without querying the (exact_)filename of this BDS. */ 4843 if (bs->file->bs->full_open_options) { 4844 qdict_put_str(opts, "driver", drv->format_name); 4845 QINCREF(bs->file->bs->full_open_options); 4846 qdict_put(opts, "file", bs->file->bs->full_open_options); 4847 4848 bs->full_open_options = opts; 4849 } else { 4850 QDECREF(opts); 4851 } 4852 } else if (!bs->full_open_options && qdict_size(bs->options)) { 4853 /* There is no underlying file BDS (at least referenced by BDS.file), 4854 * so the full options QDict should be equal to the options given 4855 * specifically for this block device when it was opened (plus the 4856 * driver specification). 4857 * Because those options don't change, there is no need to update 4858 * full_open_options when it's already set. */ 4859 4860 opts = qdict_new(); 4861 append_open_options(opts, bs); 4862 qdict_put_str(opts, "driver", drv->format_name); 4863 4864 if (bs->exact_filename[0]) { 4865 /* This may not work for all block protocol drivers (some may 4866 * require this filename to be parsed), but we have to find some 4867 * default solution here, so just include it. If some block driver 4868 * does not support pure options without any filename at all or 4869 * needs some special format of the options QDict, it needs to 4870 * implement the driver-specific bdrv_refresh_filename() function. 4871 */ 4872 qdict_put_str(opts, "filename", bs->exact_filename); 4873 } 4874 4875 bs->full_open_options = opts; 4876 } 4877 4878 if (bs->exact_filename[0]) { 4879 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename); 4880 } else if (bs->full_open_options) { 4881 QString *json = qobject_to_json(QOBJECT(bs->full_open_options)); 4882 snprintf(bs->filename, sizeof(bs->filename), "json:%s", 4883 qstring_get_str(json)); 4884 QDECREF(json); 4885 } 4886 } 4887 4888 /* 4889 * Hot add/remove a BDS's child. So the user can take a child offline when 4890 * it is broken and take a new child online 4891 */ 4892 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, 4893 Error **errp) 4894 { 4895 4896 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) { 4897 error_setg(errp, "The node %s does not support adding a child", 4898 bdrv_get_device_or_node_name(parent_bs)); 4899 return; 4900 } 4901 4902 if (!QLIST_EMPTY(&child_bs->parents)) { 4903 error_setg(errp, "The node %s already has a parent", 4904 child_bs->node_name); 4905 return; 4906 } 4907 4908 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp); 4909 } 4910 4911 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp) 4912 { 4913 BdrvChild *tmp; 4914 4915 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) { 4916 error_setg(errp, "The node %s does not support removing a child", 4917 bdrv_get_device_or_node_name(parent_bs)); 4918 return; 4919 } 4920 4921 QLIST_FOREACH(tmp, &parent_bs->children, next) { 4922 if (tmp == child) { 4923 break; 4924 } 4925 } 4926 4927 if (!tmp) { 4928 error_setg(errp, "The node %s does not have a child named %s", 4929 bdrv_get_device_or_node_name(parent_bs), 4930 bdrv_get_device_or_node_name(child->bs)); 4931 return; 4932 } 4933 4934 parent_bs->drv->bdrv_del_child(parent_bs, child, errp); 4935 } 4936