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 25 #include "qemu/osdep.h" 26 #include "block/trace.h" 27 #include "block/block_int.h" 28 #include "block/blockjob.h" 29 #include "block/nbd.h" 30 #include "block/qdict.h" 31 #include "qemu/error-report.h" 32 #include "module_block.h" 33 #include "qemu/module.h" 34 #include "qapi/error.h" 35 #include "qapi/qmp/qdict.h" 36 #include "qapi/qmp/qjson.h" 37 #include "qapi/qmp/qnull.h" 38 #include "qapi/qmp/qstring.h" 39 #include "qapi/qobject-output-visitor.h" 40 #include "qapi/qapi-visit-block-core.h" 41 #include "sysemu/block-backend.h" 42 #include "sysemu/sysemu.h" 43 #include "qemu/notify.h" 44 #include "qemu/option.h" 45 #include "qemu/coroutine.h" 46 #include "block/qapi.h" 47 #include "qemu/timer.h" 48 #include "qemu/cutils.h" 49 #include "qemu/id.h" 50 51 #ifdef CONFIG_BSD 52 #include <sys/ioctl.h> 53 #include <sys/queue.h> 54 #ifndef __DragonFly__ 55 #include <sys/disk.h> 56 #endif 57 #endif 58 59 #ifdef _WIN32 60 #include <windows.h> 61 #endif 62 63 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ 64 65 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states = 66 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states); 67 68 static QTAILQ_HEAD(, BlockDriverState) all_bdrv_states = 69 QTAILQ_HEAD_INITIALIZER(all_bdrv_states); 70 71 static QLIST_HEAD(, BlockDriver) bdrv_drivers = 72 QLIST_HEAD_INITIALIZER(bdrv_drivers); 73 74 static BlockDriverState *bdrv_open_inherit(const char *filename, 75 const char *reference, 76 QDict *options, int flags, 77 BlockDriverState *parent, 78 const BdrvChildRole *child_role, 79 Error **errp); 80 81 /* If non-zero, use only whitelisted block drivers */ 82 static int use_bdrv_whitelist; 83 84 #ifdef _WIN32 85 static int is_windows_drive_prefix(const char *filename) 86 { 87 return (((filename[0] >= 'a' && filename[0] <= 'z') || 88 (filename[0] >= 'A' && filename[0] <= 'Z')) && 89 filename[1] == ':'); 90 } 91 92 int is_windows_drive(const char *filename) 93 { 94 if (is_windows_drive_prefix(filename) && 95 filename[2] == '\0') 96 return 1; 97 if (strstart(filename, "\\\\.\\", NULL) || 98 strstart(filename, "//./", NULL)) 99 return 1; 100 return 0; 101 } 102 #endif 103 104 size_t bdrv_opt_mem_align(BlockDriverState *bs) 105 { 106 if (!bs || !bs->drv) { 107 /* page size or 4k (hdd sector size) should be on the safe side */ 108 return MAX(4096, getpagesize()); 109 } 110 111 return bs->bl.opt_mem_alignment; 112 } 113 114 size_t bdrv_min_mem_align(BlockDriverState *bs) 115 { 116 if (!bs || !bs->drv) { 117 /* page size or 4k (hdd sector size) should be on the safe side */ 118 return MAX(4096, getpagesize()); 119 } 120 121 return bs->bl.min_mem_alignment; 122 } 123 124 /* check if the path starts with "<protocol>:" */ 125 int path_has_protocol(const char *path) 126 { 127 const char *p; 128 129 #ifdef _WIN32 130 if (is_windows_drive(path) || 131 is_windows_drive_prefix(path)) { 132 return 0; 133 } 134 p = path + strcspn(path, ":/\\"); 135 #else 136 p = path + strcspn(path, ":/"); 137 #endif 138 139 return *p == ':'; 140 } 141 142 int path_is_absolute(const char *path) 143 { 144 #ifdef _WIN32 145 /* specific case for names like: "\\.\d:" */ 146 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { 147 return 1; 148 } 149 return (*path == '/' || *path == '\\'); 150 #else 151 return (*path == '/'); 152 #endif 153 } 154 155 /* if filename is absolute, just copy it to dest. Otherwise, build a 156 path to it by considering it is relative to base_path. URL are 157 supported. */ 158 void path_combine(char *dest, int dest_size, 159 const char *base_path, 160 const char *filename) 161 { 162 const char *p, *p1; 163 int len; 164 165 if (dest_size <= 0) 166 return; 167 if (path_is_absolute(filename)) { 168 pstrcpy(dest, dest_size, filename); 169 } else { 170 const char *protocol_stripped = NULL; 171 172 if (path_has_protocol(base_path)) { 173 protocol_stripped = strchr(base_path, ':'); 174 if (protocol_stripped) { 175 protocol_stripped++; 176 } 177 } 178 p = protocol_stripped ?: base_path; 179 180 p1 = strrchr(base_path, '/'); 181 #ifdef _WIN32 182 { 183 const char *p2; 184 p2 = strrchr(base_path, '\\'); 185 if (!p1 || p2 > p1) 186 p1 = p2; 187 } 188 #endif 189 if (p1) 190 p1++; 191 else 192 p1 = base_path; 193 if (p1 > p) 194 p = p1; 195 len = p - base_path; 196 if (len > dest_size - 1) 197 len = dest_size - 1; 198 memcpy(dest, base_path, len); 199 dest[len] = '\0'; 200 pstrcat(dest, dest_size, filename); 201 } 202 } 203 204 /* 205 * Helper function for bdrv_parse_filename() implementations to remove optional 206 * protocol prefixes (especially "file:") from a filename and for putting the 207 * stripped filename into the options QDict if there is such a prefix. 208 */ 209 void bdrv_parse_filename_strip_prefix(const char *filename, const char *prefix, 210 QDict *options) 211 { 212 if (strstart(filename, prefix, &filename)) { 213 /* Stripping the explicit protocol prefix may result in a protocol 214 * prefix being (wrongly) detected (if the filename contains a colon) */ 215 if (path_has_protocol(filename)) { 216 QString *fat_filename; 217 218 /* This means there is some colon before the first slash; therefore, 219 * this cannot be an absolute path */ 220 assert(!path_is_absolute(filename)); 221 222 /* And we can thus fix the protocol detection issue by prefixing it 223 * by "./" */ 224 fat_filename = qstring_from_str("./"); 225 qstring_append(fat_filename, filename); 226 227 assert(!path_has_protocol(qstring_get_str(fat_filename))); 228 229 qdict_put(options, "filename", fat_filename); 230 } else { 231 /* If no protocol prefix was detected, we can use the shortened 232 * filename as-is */ 233 qdict_put_str(options, "filename", filename); 234 } 235 } 236 } 237 238 239 /* Returns whether the image file is opened as read-only. Note that this can 240 * return false and writing to the image file is still not possible because the 241 * image is inactivated. */ 242 bool bdrv_is_read_only(BlockDriverState *bs) 243 { 244 return bs->read_only; 245 } 246 247 int bdrv_can_set_read_only(BlockDriverState *bs, bool read_only, 248 bool ignore_allow_rdw, Error **errp) 249 { 250 /* Do not set read_only if copy_on_read is enabled */ 251 if (bs->copy_on_read && read_only) { 252 error_setg(errp, "Can't set node '%s' to r/o with copy-on-read enabled", 253 bdrv_get_device_or_node_name(bs)); 254 return -EINVAL; 255 } 256 257 /* Do not clear read_only if it is prohibited */ 258 if (!read_only && !(bs->open_flags & BDRV_O_ALLOW_RDWR) && 259 !ignore_allow_rdw) 260 { 261 error_setg(errp, "Node '%s' is read only", 262 bdrv_get_device_or_node_name(bs)); 263 return -EPERM; 264 } 265 266 return 0; 267 } 268 269 /* TODO Remove (deprecated since 2.11) 270 * Block drivers are not supposed to automatically change bs->read_only. 271 * Instead, they should just check whether they can provide what the user 272 * explicitly requested and error out if read-write is requested, but they can 273 * only provide read-only access. */ 274 int bdrv_set_read_only(BlockDriverState *bs, bool read_only, Error **errp) 275 { 276 int ret = 0; 277 278 ret = bdrv_can_set_read_only(bs, read_only, false, errp); 279 if (ret < 0) { 280 return ret; 281 } 282 283 bs->read_only = read_only; 284 return 0; 285 } 286 287 void bdrv_get_full_backing_filename_from_filename(const char *backed, 288 const char *backing, 289 char *dest, size_t sz, 290 Error **errp) 291 { 292 if (backing[0] == '\0' || path_has_protocol(backing) || 293 path_is_absolute(backing)) 294 { 295 pstrcpy(dest, sz, backing); 296 } else if (backed[0] == '\0' || strstart(backed, "json:", NULL)) { 297 error_setg(errp, "Cannot use relative backing file names for '%s'", 298 backed); 299 } else { 300 path_combine(dest, sz, backed, backing); 301 } 302 } 303 304 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz, 305 Error **errp) 306 { 307 char *backed = bs->exact_filename[0] ? bs->exact_filename : bs->filename; 308 309 bdrv_get_full_backing_filename_from_filename(backed, bs->backing_file, 310 dest, sz, errp); 311 } 312 313 void bdrv_register(BlockDriver *bdrv) 314 { 315 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); 316 } 317 318 BlockDriverState *bdrv_new(void) 319 { 320 BlockDriverState *bs; 321 int i; 322 323 bs = g_new0(BlockDriverState, 1); 324 QLIST_INIT(&bs->dirty_bitmaps); 325 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 326 QLIST_INIT(&bs->op_blockers[i]); 327 } 328 notifier_with_return_list_init(&bs->before_write_notifiers); 329 qemu_co_mutex_init(&bs->reqs_lock); 330 qemu_mutex_init(&bs->dirty_bitmap_mutex); 331 bs->refcnt = 1; 332 bs->aio_context = qemu_get_aio_context(); 333 334 qemu_co_queue_init(&bs->flush_queue); 335 336 for (i = 0; i < bdrv_drain_all_count; i++) { 337 bdrv_drained_begin(bs); 338 } 339 340 QTAILQ_INSERT_TAIL(&all_bdrv_states, bs, bs_list); 341 342 return bs; 343 } 344 345 static BlockDriver *bdrv_do_find_format(const char *format_name) 346 { 347 BlockDriver *drv1; 348 349 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 350 if (!strcmp(drv1->format_name, format_name)) { 351 return drv1; 352 } 353 } 354 355 return NULL; 356 } 357 358 BlockDriver *bdrv_find_format(const char *format_name) 359 { 360 BlockDriver *drv1; 361 int i; 362 363 drv1 = bdrv_do_find_format(format_name); 364 if (drv1) { 365 return drv1; 366 } 367 368 /* The driver isn't registered, maybe we need to load a module */ 369 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { 370 if (!strcmp(block_driver_modules[i].format_name, format_name)) { 371 block_module_load_one(block_driver_modules[i].library_name); 372 break; 373 } 374 } 375 376 return bdrv_do_find_format(format_name); 377 } 378 379 int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) 380 { 381 static const char *whitelist_rw[] = { 382 CONFIG_BDRV_RW_WHITELIST 383 }; 384 static const char *whitelist_ro[] = { 385 CONFIG_BDRV_RO_WHITELIST 386 }; 387 const char **p; 388 389 if (!whitelist_rw[0] && !whitelist_ro[0]) { 390 return 1; /* no whitelist, anything goes */ 391 } 392 393 for (p = whitelist_rw; *p; p++) { 394 if (!strcmp(drv->format_name, *p)) { 395 return 1; 396 } 397 } 398 if (read_only) { 399 for (p = whitelist_ro; *p; p++) { 400 if (!strcmp(drv->format_name, *p)) { 401 return 1; 402 } 403 } 404 } 405 return 0; 406 } 407 408 bool bdrv_uses_whitelist(void) 409 { 410 return use_bdrv_whitelist; 411 } 412 413 typedef struct CreateCo { 414 BlockDriver *drv; 415 char *filename; 416 QemuOpts *opts; 417 int ret; 418 Error *err; 419 } CreateCo; 420 421 static void coroutine_fn bdrv_create_co_entry(void *opaque) 422 { 423 Error *local_err = NULL; 424 int ret; 425 426 CreateCo *cco = opaque; 427 assert(cco->drv); 428 429 ret = cco->drv->bdrv_co_create_opts(cco->filename, cco->opts, &local_err); 430 error_propagate(&cco->err, local_err); 431 cco->ret = ret; 432 } 433 434 int bdrv_create(BlockDriver *drv, const char* filename, 435 QemuOpts *opts, Error **errp) 436 { 437 int ret; 438 439 Coroutine *co; 440 CreateCo cco = { 441 .drv = drv, 442 .filename = g_strdup(filename), 443 .opts = opts, 444 .ret = NOT_DONE, 445 .err = NULL, 446 }; 447 448 if (!drv->bdrv_co_create_opts) { 449 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); 450 ret = -ENOTSUP; 451 goto out; 452 } 453 454 if (qemu_in_coroutine()) { 455 /* Fast-path if already in coroutine context */ 456 bdrv_create_co_entry(&cco); 457 } else { 458 co = qemu_coroutine_create(bdrv_create_co_entry, &cco); 459 qemu_coroutine_enter(co); 460 while (cco.ret == NOT_DONE) { 461 aio_poll(qemu_get_aio_context(), true); 462 } 463 } 464 465 ret = cco.ret; 466 if (ret < 0) { 467 if (cco.err) { 468 error_propagate(errp, cco.err); 469 } else { 470 error_setg_errno(errp, -ret, "Could not create image"); 471 } 472 } 473 474 out: 475 g_free(cco.filename); 476 return ret; 477 } 478 479 int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp) 480 { 481 BlockDriver *drv; 482 Error *local_err = NULL; 483 int ret; 484 485 drv = bdrv_find_protocol(filename, true, errp); 486 if (drv == NULL) { 487 return -ENOENT; 488 } 489 490 ret = bdrv_create(drv, filename, opts, &local_err); 491 error_propagate(errp, local_err); 492 return ret; 493 } 494 495 /** 496 * Try to get @bs's logical and physical block size. 497 * On success, store them in @bsz struct and return 0. 498 * On failure return -errno. 499 * @bs must not be empty. 500 */ 501 int bdrv_probe_blocksizes(BlockDriverState *bs, BlockSizes *bsz) 502 { 503 BlockDriver *drv = bs->drv; 504 505 if (drv && drv->bdrv_probe_blocksizes) { 506 return drv->bdrv_probe_blocksizes(bs, bsz); 507 } else if (drv && drv->is_filter && bs->file) { 508 return bdrv_probe_blocksizes(bs->file->bs, bsz); 509 } 510 511 return -ENOTSUP; 512 } 513 514 /** 515 * Try to get @bs's geometry (cyls, heads, sectors). 516 * On success, store them in @geo struct and return 0. 517 * On failure return -errno. 518 * @bs must not be empty. 519 */ 520 int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry *geo) 521 { 522 BlockDriver *drv = bs->drv; 523 524 if (drv && drv->bdrv_probe_geometry) { 525 return drv->bdrv_probe_geometry(bs, geo); 526 } else if (drv && drv->is_filter && bs->file) { 527 return bdrv_probe_geometry(bs->file->bs, geo); 528 } 529 530 return -ENOTSUP; 531 } 532 533 /* 534 * Create a uniquely-named empty temporary file. 535 * Return 0 upon success, otherwise a negative errno value. 536 */ 537 int get_tmp_filename(char *filename, int size) 538 { 539 #ifdef _WIN32 540 char temp_dir[MAX_PATH]; 541 /* GetTempFileName requires that its output buffer (4th param) 542 have length MAX_PATH or greater. */ 543 assert(size >= MAX_PATH); 544 return (GetTempPath(MAX_PATH, temp_dir) 545 && GetTempFileName(temp_dir, "qem", 0, filename) 546 ? 0 : -GetLastError()); 547 #else 548 int fd; 549 const char *tmpdir; 550 tmpdir = getenv("TMPDIR"); 551 if (!tmpdir) { 552 tmpdir = "/var/tmp"; 553 } 554 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { 555 return -EOVERFLOW; 556 } 557 fd = mkstemp(filename); 558 if (fd < 0) { 559 return -errno; 560 } 561 if (close(fd) != 0) { 562 unlink(filename); 563 return -errno; 564 } 565 return 0; 566 #endif 567 } 568 569 /* 570 * Detect host devices. By convention, /dev/cdrom[N] is always 571 * recognized as a host CDROM. 572 */ 573 static BlockDriver *find_hdev_driver(const char *filename) 574 { 575 int score_max = 0, score; 576 BlockDriver *drv = NULL, *d; 577 578 QLIST_FOREACH(d, &bdrv_drivers, list) { 579 if (d->bdrv_probe_device) { 580 score = d->bdrv_probe_device(filename); 581 if (score > score_max) { 582 score_max = score; 583 drv = d; 584 } 585 } 586 } 587 588 return drv; 589 } 590 591 static BlockDriver *bdrv_do_find_protocol(const char *protocol) 592 { 593 BlockDriver *drv1; 594 595 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 596 if (drv1->protocol_name && !strcmp(drv1->protocol_name, protocol)) { 597 return drv1; 598 } 599 } 600 601 return NULL; 602 } 603 604 BlockDriver *bdrv_find_protocol(const char *filename, 605 bool allow_protocol_prefix, 606 Error **errp) 607 { 608 BlockDriver *drv1; 609 char protocol[128]; 610 int len; 611 const char *p; 612 int i; 613 614 /* TODO Drivers without bdrv_file_open must be specified explicitly */ 615 616 /* 617 * XXX(hch): we really should not let host device detection 618 * override an explicit protocol specification, but moving this 619 * later breaks access to device names with colons in them. 620 * Thanks to the brain-dead persistent naming schemes on udev- 621 * based Linux systems those actually are quite common. 622 */ 623 drv1 = find_hdev_driver(filename); 624 if (drv1) { 625 return drv1; 626 } 627 628 if (!path_has_protocol(filename) || !allow_protocol_prefix) { 629 return &bdrv_file; 630 } 631 632 p = strchr(filename, ':'); 633 assert(p != NULL); 634 len = p - filename; 635 if (len > sizeof(protocol) - 1) 636 len = sizeof(protocol) - 1; 637 memcpy(protocol, filename, len); 638 protocol[len] = '\0'; 639 640 drv1 = bdrv_do_find_protocol(protocol); 641 if (drv1) { 642 return drv1; 643 } 644 645 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); ++i) { 646 if (block_driver_modules[i].protocol_name && 647 !strcmp(block_driver_modules[i].protocol_name, protocol)) { 648 block_module_load_one(block_driver_modules[i].library_name); 649 break; 650 } 651 } 652 653 drv1 = bdrv_do_find_protocol(protocol); 654 if (!drv1) { 655 error_setg(errp, "Unknown protocol '%s'", protocol); 656 } 657 return drv1; 658 } 659 660 /* 661 * Guess image format by probing its contents. 662 * This is not a good idea when your image is raw (CVE-2008-2004), but 663 * we do it anyway for backward compatibility. 664 * 665 * @buf contains the image's first @buf_size bytes. 666 * @buf_size is the buffer size in bytes (generally BLOCK_PROBE_BUF_SIZE, 667 * but can be smaller if the image file is smaller) 668 * @filename is its filename. 669 * 670 * For all block drivers, call the bdrv_probe() method to get its 671 * probing score. 672 * Return the first block driver with the highest probing score. 673 */ 674 BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, 675 const char *filename) 676 { 677 int score_max = 0, score; 678 BlockDriver *drv = NULL, *d; 679 680 QLIST_FOREACH(d, &bdrv_drivers, list) { 681 if (d->bdrv_probe) { 682 score = d->bdrv_probe(buf, buf_size, filename); 683 if (score > score_max) { 684 score_max = score; 685 drv = d; 686 } 687 } 688 } 689 690 return drv; 691 } 692 693 static int find_image_format(BlockBackend *file, const char *filename, 694 BlockDriver **pdrv, Error **errp) 695 { 696 BlockDriver *drv; 697 uint8_t buf[BLOCK_PROBE_BUF_SIZE]; 698 int ret = 0; 699 700 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ 701 if (blk_is_sg(file) || !blk_is_inserted(file) || blk_getlength(file) == 0) { 702 *pdrv = &bdrv_raw; 703 return ret; 704 } 705 706 ret = blk_pread(file, 0, buf, sizeof(buf)); 707 if (ret < 0) { 708 error_setg_errno(errp, -ret, "Could not read image for determining its " 709 "format"); 710 *pdrv = NULL; 711 return ret; 712 } 713 714 drv = bdrv_probe_all(buf, ret, filename); 715 if (!drv) { 716 error_setg(errp, "Could not determine image format: No compatible " 717 "driver found"); 718 ret = -ENOENT; 719 } 720 *pdrv = drv; 721 return ret; 722 } 723 724 /** 725 * Set the current 'total_sectors' value 726 * Return 0 on success, -errno on error. 727 */ 728 int refresh_total_sectors(BlockDriverState *bs, int64_t hint) 729 { 730 BlockDriver *drv = bs->drv; 731 732 if (!drv) { 733 return -ENOMEDIUM; 734 } 735 736 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ 737 if (bdrv_is_sg(bs)) 738 return 0; 739 740 /* query actual device if possible, otherwise just trust the hint */ 741 if (drv->bdrv_getlength) { 742 int64_t length = drv->bdrv_getlength(bs); 743 if (length < 0) { 744 return length; 745 } 746 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); 747 } 748 749 bs->total_sectors = hint; 750 return 0; 751 } 752 753 /** 754 * Combines a QDict of new block driver @options with any missing options taken 755 * from @old_options, so that leaving out an option defaults to its old value. 756 */ 757 static void bdrv_join_options(BlockDriverState *bs, QDict *options, 758 QDict *old_options) 759 { 760 if (bs->drv && bs->drv->bdrv_join_options) { 761 bs->drv->bdrv_join_options(options, old_options); 762 } else { 763 qdict_join(options, old_options, false); 764 } 765 } 766 767 /** 768 * Set open flags for a given discard mode 769 * 770 * Return 0 on success, -1 if the discard mode was invalid. 771 */ 772 int bdrv_parse_discard_flags(const char *mode, int *flags) 773 { 774 *flags &= ~BDRV_O_UNMAP; 775 776 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { 777 /* do nothing */ 778 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { 779 *flags |= BDRV_O_UNMAP; 780 } else { 781 return -1; 782 } 783 784 return 0; 785 } 786 787 /** 788 * Set open flags for a given cache mode 789 * 790 * Return 0 on success, -1 if the cache mode was invalid. 791 */ 792 int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough) 793 { 794 *flags &= ~BDRV_O_CACHE_MASK; 795 796 if (!strcmp(mode, "off") || !strcmp(mode, "none")) { 797 *writethrough = false; 798 *flags |= BDRV_O_NOCACHE; 799 } else if (!strcmp(mode, "directsync")) { 800 *writethrough = true; 801 *flags |= BDRV_O_NOCACHE; 802 } else if (!strcmp(mode, "writeback")) { 803 *writethrough = false; 804 } else if (!strcmp(mode, "unsafe")) { 805 *writethrough = false; 806 *flags |= BDRV_O_NO_FLUSH; 807 } else if (!strcmp(mode, "writethrough")) { 808 *writethrough = true; 809 } else { 810 return -1; 811 } 812 813 return 0; 814 } 815 816 static char *bdrv_child_get_parent_desc(BdrvChild *c) 817 { 818 BlockDriverState *parent = c->opaque; 819 return g_strdup(bdrv_get_device_or_node_name(parent)); 820 } 821 822 static void bdrv_child_cb_drained_begin(BdrvChild *child) 823 { 824 BlockDriverState *bs = child->opaque; 825 bdrv_do_drained_begin_quiesce(bs, NULL, false); 826 } 827 828 static bool bdrv_child_cb_drained_poll(BdrvChild *child) 829 { 830 BlockDriverState *bs = child->opaque; 831 return bdrv_drain_poll(bs, false, NULL, false); 832 } 833 834 static void bdrv_child_cb_drained_end(BdrvChild *child) 835 { 836 BlockDriverState *bs = child->opaque; 837 bdrv_drained_end(bs); 838 } 839 840 static void bdrv_child_cb_attach(BdrvChild *child) 841 { 842 BlockDriverState *bs = child->opaque; 843 bdrv_apply_subtree_drain(child, bs); 844 } 845 846 static void bdrv_child_cb_detach(BdrvChild *child) 847 { 848 BlockDriverState *bs = child->opaque; 849 bdrv_unapply_subtree_drain(child, bs); 850 } 851 852 static int bdrv_child_cb_inactivate(BdrvChild *child) 853 { 854 BlockDriverState *bs = child->opaque; 855 assert(bs->open_flags & BDRV_O_INACTIVE); 856 return 0; 857 } 858 859 /* 860 * Returns the options and flags that a temporary snapshot should get, based on 861 * the originally requested flags (the originally requested image will have 862 * flags like a backing file) 863 */ 864 static void bdrv_temp_snapshot_options(int *child_flags, QDict *child_options, 865 int parent_flags, QDict *parent_options) 866 { 867 *child_flags = (parent_flags & ~BDRV_O_SNAPSHOT) | BDRV_O_TEMPORARY; 868 869 /* For temporary files, unconditional cache=unsafe is fine */ 870 qdict_set_default_str(child_options, BDRV_OPT_CACHE_DIRECT, "off"); 871 qdict_set_default_str(child_options, BDRV_OPT_CACHE_NO_FLUSH, "on"); 872 873 /* Copy the read-only option from the parent */ 874 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); 875 876 /* aio=native doesn't work for cache.direct=off, so disable it for the 877 * temporary snapshot */ 878 *child_flags &= ~BDRV_O_NATIVE_AIO; 879 } 880 881 /* 882 * Returns the options and flags that bs->file should get if a protocol driver 883 * is expected, based on the given options and flags for the parent BDS 884 */ 885 static void bdrv_inherited_options(int *child_flags, QDict *child_options, 886 int parent_flags, QDict *parent_options) 887 { 888 int flags = parent_flags; 889 890 /* Enable protocol handling, disable format probing for bs->file */ 891 flags |= BDRV_O_PROTOCOL; 892 893 /* If the cache mode isn't explicitly set, inherit direct and no-flush from 894 * the parent. */ 895 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); 896 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); 897 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); 898 899 /* Inherit the read-only option from the parent if it's not set */ 900 qdict_copy_default(child_options, parent_options, BDRV_OPT_READ_ONLY); 901 902 /* Our block drivers take care to send flushes and respect unmap policy, 903 * so we can default to enable both on lower layers regardless of the 904 * corresponding parent options. */ 905 qdict_set_default_str(child_options, BDRV_OPT_DISCARD, "unmap"); 906 907 /* Clear flags that only apply to the top layer */ 908 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ | 909 BDRV_O_NO_IO); 910 911 *child_flags = flags; 912 } 913 914 const BdrvChildRole child_file = { 915 .parent_is_bds = true, 916 .get_parent_desc = bdrv_child_get_parent_desc, 917 .inherit_options = bdrv_inherited_options, 918 .drained_begin = bdrv_child_cb_drained_begin, 919 .drained_poll = bdrv_child_cb_drained_poll, 920 .drained_end = bdrv_child_cb_drained_end, 921 .attach = bdrv_child_cb_attach, 922 .detach = bdrv_child_cb_detach, 923 .inactivate = bdrv_child_cb_inactivate, 924 }; 925 926 /* 927 * Returns the options and flags that bs->file should get if the use of formats 928 * (and not only protocols) is permitted for it, based on the given options and 929 * flags for the parent BDS 930 */ 931 static void bdrv_inherited_fmt_options(int *child_flags, QDict *child_options, 932 int parent_flags, QDict *parent_options) 933 { 934 child_file.inherit_options(child_flags, child_options, 935 parent_flags, parent_options); 936 937 *child_flags &= ~(BDRV_O_PROTOCOL | BDRV_O_NO_IO); 938 } 939 940 const BdrvChildRole child_format = { 941 .parent_is_bds = true, 942 .get_parent_desc = bdrv_child_get_parent_desc, 943 .inherit_options = bdrv_inherited_fmt_options, 944 .drained_begin = bdrv_child_cb_drained_begin, 945 .drained_poll = bdrv_child_cb_drained_poll, 946 .drained_end = bdrv_child_cb_drained_end, 947 .attach = bdrv_child_cb_attach, 948 .detach = bdrv_child_cb_detach, 949 .inactivate = bdrv_child_cb_inactivate, 950 }; 951 952 static void bdrv_backing_attach(BdrvChild *c) 953 { 954 BlockDriverState *parent = c->opaque; 955 BlockDriverState *backing_hd = c->bs; 956 957 assert(!parent->backing_blocker); 958 error_setg(&parent->backing_blocker, 959 "node is used as backing hd of '%s'", 960 bdrv_get_device_or_node_name(parent)); 961 962 parent->open_flags &= ~BDRV_O_NO_BACKING; 963 pstrcpy(parent->backing_file, sizeof(parent->backing_file), 964 backing_hd->filename); 965 pstrcpy(parent->backing_format, sizeof(parent->backing_format), 966 backing_hd->drv ? backing_hd->drv->format_name : ""); 967 968 bdrv_op_block_all(backing_hd, parent->backing_blocker); 969 /* Otherwise we won't be able to commit or stream */ 970 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_COMMIT_TARGET, 971 parent->backing_blocker); 972 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_STREAM, 973 parent->backing_blocker); 974 /* 975 * We do backup in 3 ways: 976 * 1. drive backup 977 * The target bs is new opened, and the source is top BDS 978 * 2. blockdev backup 979 * Both the source and the target are top BDSes. 980 * 3. internal backup(used for block replication) 981 * Both the source and the target are backing file 982 * 983 * In case 1 and 2, neither the source nor the target is the backing file. 984 * In case 3, we will block the top BDS, so there is only one block job 985 * for the top BDS and its backing chain. 986 */ 987 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_SOURCE, 988 parent->backing_blocker); 989 bdrv_op_unblock(backing_hd, BLOCK_OP_TYPE_BACKUP_TARGET, 990 parent->backing_blocker); 991 992 bdrv_child_cb_attach(c); 993 } 994 995 static void bdrv_backing_detach(BdrvChild *c) 996 { 997 BlockDriverState *parent = c->opaque; 998 999 assert(parent->backing_blocker); 1000 bdrv_op_unblock_all(c->bs, parent->backing_blocker); 1001 error_free(parent->backing_blocker); 1002 parent->backing_blocker = NULL; 1003 1004 bdrv_child_cb_detach(c); 1005 } 1006 1007 /* 1008 * Returns the options and flags that bs->backing should get, based on the 1009 * given options and flags for the parent BDS 1010 */ 1011 static void bdrv_backing_options(int *child_flags, QDict *child_options, 1012 int parent_flags, QDict *parent_options) 1013 { 1014 int flags = parent_flags; 1015 1016 /* The cache mode is inherited unmodified for backing files; except WCE, 1017 * which is only applied on the top level (BlockBackend) */ 1018 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_DIRECT); 1019 qdict_copy_default(child_options, parent_options, BDRV_OPT_CACHE_NO_FLUSH); 1020 qdict_copy_default(child_options, parent_options, BDRV_OPT_FORCE_SHARE); 1021 1022 /* backing files always opened read-only */ 1023 qdict_set_default_str(child_options, BDRV_OPT_READ_ONLY, "on"); 1024 flags &= ~BDRV_O_COPY_ON_READ; 1025 1026 /* snapshot=on is handled on the top layer */ 1027 flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_TEMPORARY); 1028 1029 *child_flags = flags; 1030 } 1031 1032 static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base, 1033 const char *filename, Error **errp) 1034 { 1035 BlockDriverState *parent = c->opaque; 1036 int orig_flags = bdrv_get_flags(parent); 1037 int ret; 1038 1039 if (!(orig_flags & BDRV_O_RDWR)) { 1040 ret = bdrv_reopen(parent, orig_flags | BDRV_O_RDWR, errp); 1041 if (ret < 0) { 1042 return ret; 1043 } 1044 } 1045 1046 ret = bdrv_change_backing_file(parent, filename, 1047 base->drv ? base->drv->format_name : ""); 1048 if (ret < 0) { 1049 error_setg_errno(errp, -ret, "Could not update backing file link"); 1050 } 1051 1052 if (!(orig_flags & BDRV_O_RDWR)) { 1053 bdrv_reopen(parent, orig_flags, NULL); 1054 } 1055 1056 return ret; 1057 } 1058 1059 const BdrvChildRole child_backing = { 1060 .parent_is_bds = true, 1061 .get_parent_desc = bdrv_child_get_parent_desc, 1062 .attach = bdrv_backing_attach, 1063 .detach = bdrv_backing_detach, 1064 .inherit_options = bdrv_backing_options, 1065 .drained_begin = bdrv_child_cb_drained_begin, 1066 .drained_poll = bdrv_child_cb_drained_poll, 1067 .drained_end = bdrv_child_cb_drained_end, 1068 .inactivate = bdrv_child_cb_inactivate, 1069 .update_filename = bdrv_backing_update_filename, 1070 }; 1071 1072 static int bdrv_open_flags(BlockDriverState *bs, int flags) 1073 { 1074 int open_flags = flags; 1075 1076 /* 1077 * Clear flags that are internal to the block layer before opening the 1078 * image. 1079 */ 1080 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_PROTOCOL); 1081 1082 /* 1083 * Snapshots should be writable. 1084 */ 1085 if (flags & BDRV_O_TEMPORARY) { 1086 open_flags |= BDRV_O_RDWR; 1087 } 1088 1089 return open_flags; 1090 } 1091 1092 static void update_flags_from_options(int *flags, QemuOpts *opts) 1093 { 1094 *flags &= ~BDRV_O_CACHE_MASK; 1095 1096 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_NO_FLUSH)); 1097 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) { 1098 *flags |= BDRV_O_NO_FLUSH; 1099 } 1100 1101 assert(qemu_opt_find(opts, BDRV_OPT_CACHE_DIRECT)); 1102 if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) { 1103 *flags |= BDRV_O_NOCACHE; 1104 } 1105 1106 *flags &= ~BDRV_O_RDWR; 1107 1108 assert(qemu_opt_find(opts, BDRV_OPT_READ_ONLY)); 1109 if (!qemu_opt_get_bool(opts, BDRV_OPT_READ_ONLY, false)) { 1110 *flags |= BDRV_O_RDWR; 1111 } 1112 1113 } 1114 1115 static void update_options_from_flags(QDict *options, int flags) 1116 { 1117 if (!qdict_haskey(options, BDRV_OPT_CACHE_DIRECT)) { 1118 qdict_put_bool(options, BDRV_OPT_CACHE_DIRECT, flags & BDRV_O_NOCACHE); 1119 } 1120 if (!qdict_haskey(options, BDRV_OPT_CACHE_NO_FLUSH)) { 1121 qdict_put_bool(options, BDRV_OPT_CACHE_NO_FLUSH, 1122 flags & BDRV_O_NO_FLUSH); 1123 } 1124 if (!qdict_haskey(options, BDRV_OPT_READ_ONLY)) { 1125 qdict_put_bool(options, BDRV_OPT_READ_ONLY, !(flags & BDRV_O_RDWR)); 1126 } 1127 } 1128 1129 static void bdrv_assign_node_name(BlockDriverState *bs, 1130 const char *node_name, 1131 Error **errp) 1132 { 1133 char *gen_node_name = NULL; 1134 1135 if (!node_name) { 1136 node_name = gen_node_name = id_generate(ID_BLOCK); 1137 } else if (!id_wellformed(node_name)) { 1138 /* 1139 * Check for empty string or invalid characters, but not if it is 1140 * generated (generated names use characters not available to the user) 1141 */ 1142 error_setg(errp, "Invalid node name"); 1143 return; 1144 } 1145 1146 /* takes care of avoiding namespaces collisions */ 1147 if (blk_by_name(node_name)) { 1148 error_setg(errp, "node-name=%s is conflicting with a device id", 1149 node_name); 1150 goto out; 1151 } 1152 1153 /* takes care of avoiding duplicates node names */ 1154 if (bdrv_find_node(node_name)) { 1155 error_setg(errp, "Duplicate node name"); 1156 goto out; 1157 } 1158 1159 /* Make sure that the node name isn't truncated */ 1160 if (strlen(node_name) >= sizeof(bs->node_name)) { 1161 error_setg(errp, "Node name too long"); 1162 goto out; 1163 } 1164 1165 /* copy node name into the bs and insert it into the graph list */ 1166 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name); 1167 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list); 1168 out: 1169 g_free(gen_node_name); 1170 } 1171 1172 static int bdrv_open_driver(BlockDriverState *bs, BlockDriver *drv, 1173 const char *node_name, QDict *options, 1174 int open_flags, Error **errp) 1175 { 1176 Error *local_err = NULL; 1177 int i, ret; 1178 1179 bdrv_assign_node_name(bs, node_name, &local_err); 1180 if (local_err) { 1181 error_propagate(errp, local_err); 1182 return -EINVAL; 1183 } 1184 1185 bs->drv = drv; 1186 bs->read_only = !(bs->open_flags & BDRV_O_RDWR); 1187 bs->opaque = g_malloc0(drv->instance_size); 1188 1189 if (drv->bdrv_file_open) { 1190 assert(!drv->bdrv_needs_filename || bs->filename[0]); 1191 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); 1192 } else if (drv->bdrv_open) { 1193 ret = drv->bdrv_open(bs, options, open_flags, &local_err); 1194 } else { 1195 ret = 0; 1196 } 1197 1198 if (ret < 0) { 1199 if (local_err) { 1200 error_propagate(errp, local_err); 1201 } else if (bs->filename[0]) { 1202 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); 1203 } else { 1204 error_setg_errno(errp, -ret, "Could not open image"); 1205 } 1206 goto open_failed; 1207 } 1208 1209 ret = refresh_total_sectors(bs, bs->total_sectors); 1210 if (ret < 0) { 1211 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 1212 return ret; 1213 } 1214 1215 bdrv_refresh_limits(bs, &local_err); 1216 if (local_err) { 1217 error_propagate(errp, local_err); 1218 return -EINVAL; 1219 } 1220 1221 assert(bdrv_opt_mem_align(bs) != 0); 1222 assert(bdrv_min_mem_align(bs) != 0); 1223 assert(is_power_of_2(bs->bl.request_alignment)); 1224 1225 for (i = 0; i < bs->quiesce_counter; i++) { 1226 if (drv->bdrv_co_drain_begin) { 1227 drv->bdrv_co_drain_begin(bs); 1228 } 1229 } 1230 1231 return 0; 1232 open_failed: 1233 bs->drv = NULL; 1234 if (bs->file != NULL) { 1235 bdrv_unref_child(bs, bs->file); 1236 bs->file = NULL; 1237 } 1238 g_free(bs->opaque); 1239 bs->opaque = NULL; 1240 return ret; 1241 } 1242 1243 BlockDriverState *bdrv_new_open_driver(BlockDriver *drv, const char *node_name, 1244 int flags, Error **errp) 1245 { 1246 BlockDriverState *bs; 1247 int ret; 1248 1249 bs = bdrv_new(); 1250 bs->open_flags = flags; 1251 bs->explicit_options = qdict_new(); 1252 bs->options = qdict_new(); 1253 bs->opaque = NULL; 1254 1255 update_options_from_flags(bs->options, flags); 1256 1257 ret = bdrv_open_driver(bs, drv, node_name, bs->options, flags, errp); 1258 if (ret < 0) { 1259 qobject_unref(bs->explicit_options); 1260 bs->explicit_options = NULL; 1261 qobject_unref(bs->options); 1262 bs->options = NULL; 1263 bdrv_unref(bs); 1264 return NULL; 1265 } 1266 1267 return bs; 1268 } 1269 1270 QemuOptsList bdrv_runtime_opts = { 1271 .name = "bdrv_common", 1272 .head = QTAILQ_HEAD_INITIALIZER(bdrv_runtime_opts.head), 1273 .desc = { 1274 { 1275 .name = "node-name", 1276 .type = QEMU_OPT_STRING, 1277 .help = "Node name of the block device node", 1278 }, 1279 { 1280 .name = "driver", 1281 .type = QEMU_OPT_STRING, 1282 .help = "Block driver to use for the node", 1283 }, 1284 { 1285 .name = BDRV_OPT_CACHE_DIRECT, 1286 .type = QEMU_OPT_BOOL, 1287 .help = "Bypass software writeback cache on the host", 1288 }, 1289 { 1290 .name = BDRV_OPT_CACHE_NO_FLUSH, 1291 .type = QEMU_OPT_BOOL, 1292 .help = "Ignore flush requests", 1293 }, 1294 { 1295 .name = BDRV_OPT_READ_ONLY, 1296 .type = QEMU_OPT_BOOL, 1297 .help = "Node is opened in read-only mode", 1298 }, 1299 { 1300 .name = "detect-zeroes", 1301 .type = QEMU_OPT_STRING, 1302 .help = "try to optimize zero writes (off, on, unmap)", 1303 }, 1304 { 1305 .name = "discard", 1306 .type = QEMU_OPT_STRING, 1307 .help = "discard operation (ignore/off, unmap/on)", 1308 }, 1309 { 1310 .name = BDRV_OPT_FORCE_SHARE, 1311 .type = QEMU_OPT_BOOL, 1312 .help = "always accept other writers (default: off)", 1313 }, 1314 { /* end of list */ } 1315 }, 1316 }; 1317 1318 /* 1319 * Common part for opening disk images and files 1320 * 1321 * Removes all processed options from *options. 1322 */ 1323 static int bdrv_open_common(BlockDriverState *bs, BlockBackend *file, 1324 QDict *options, Error **errp) 1325 { 1326 int ret, open_flags; 1327 const char *filename; 1328 const char *driver_name = NULL; 1329 const char *node_name = NULL; 1330 const char *discard; 1331 const char *detect_zeroes; 1332 QemuOpts *opts; 1333 BlockDriver *drv; 1334 Error *local_err = NULL; 1335 1336 assert(bs->file == NULL); 1337 assert(options != NULL && bs->options != options); 1338 1339 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); 1340 qemu_opts_absorb_qdict(opts, options, &local_err); 1341 if (local_err) { 1342 error_propagate(errp, local_err); 1343 ret = -EINVAL; 1344 goto fail_opts; 1345 } 1346 1347 update_flags_from_options(&bs->open_flags, opts); 1348 1349 driver_name = qemu_opt_get(opts, "driver"); 1350 drv = bdrv_find_format(driver_name); 1351 assert(drv != NULL); 1352 1353 bs->force_share = qemu_opt_get_bool(opts, BDRV_OPT_FORCE_SHARE, false); 1354 1355 if (bs->force_share && (bs->open_flags & BDRV_O_RDWR)) { 1356 error_setg(errp, 1357 BDRV_OPT_FORCE_SHARE 1358 "=on can only be used with read-only images"); 1359 ret = -EINVAL; 1360 goto fail_opts; 1361 } 1362 1363 if (file != NULL) { 1364 filename = blk_bs(file)->filename; 1365 } else { 1366 /* 1367 * Caution: while qdict_get_try_str() is fine, getting 1368 * non-string types would require more care. When @options 1369 * come from -blockdev or blockdev_add, its members are typed 1370 * according to the QAPI schema, but when they come from 1371 * -drive, they're all QString. 1372 */ 1373 filename = qdict_get_try_str(options, "filename"); 1374 } 1375 1376 if (drv->bdrv_needs_filename && (!filename || !filename[0])) { 1377 error_setg(errp, "The '%s' block driver requires a file name", 1378 drv->format_name); 1379 ret = -EINVAL; 1380 goto fail_opts; 1381 } 1382 1383 trace_bdrv_open_common(bs, filename ?: "", bs->open_flags, 1384 drv->format_name); 1385 1386 bs->read_only = !(bs->open_flags & BDRV_O_RDWR); 1387 1388 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { 1389 error_setg(errp, 1390 !bs->read_only && bdrv_is_whitelisted(drv, true) 1391 ? "Driver '%s' can only be used for read-only devices" 1392 : "Driver '%s' is not whitelisted", 1393 drv->format_name); 1394 ret = -ENOTSUP; 1395 goto fail_opts; 1396 } 1397 1398 /* bdrv_new() and bdrv_close() make it so */ 1399 assert(atomic_read(&bs->copy_on_read) == 0); 1400 1401 if (bs->open_flags & BDRV_O_COPY_ON_READ) { 1402 if (!bs->read_only) { 1403 bdrv_enable_copy_on_read(bs); 1404 } else { 1405 error_setg(errp, "Can't use copy-on-read on read-only device"); 1406 ret = -EINVAL; 1407 goto fail_opts; 1408 } 1409 } 1410 1411 discard = qemu_opt_get(opts, "discard"); 1412 if (discard != NULL) { 1413 if (bdrv_parse_discard_flags(discard, &bs->open_flags) != 0) { 1414 error_setg(errp, "Invalid discard option"); 1415 ret = -EINVAL; 1416 goto fail_opts; 1417 } 1418 } 1419 1420 detect_zeroes = qemu_opt_get(opts, "detect-zeroes"); 1421 if (detect_zeroes) { 1422 BlockdevDetectZeroesOptions value = 1423 qapi_enum_parse(&BlockdevDetectZeroesOptions_lookup, 1424 detect_zeroes, 1425 BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF, 1426 &local_err); 1427 if (local_err) { 1428 error_propagate(errp, local_err); 1429 ret = -EINVAL; 1430 goto fail_opts; 1431 } 1432 1433 if (value == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP && 1434 !(bs->open_flags & BDRV_O_UNMAP)) 1435 { 1436 error_setg(errp, "setting detect-zeroes to unmap is not allowed " 1437 "without setting discard operation to unmap"); 1438 ret = -EINVAL; 1439 goto fail_opts; 1440 } 1441 1442 bs->detect_zeroes = value; 1443 } 1444 1445 if (filename != NULL) { 1446 pstrcpy(bs->filename, sizeof(bs->filename), filename); 1447 } else { 1448 bs->filename[0] = '\0'; 1449 } 1450 pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename); 1451 1452 /* Open the image, either directly or using a protocol */ 1453 open_flags = bdrv_open_flags(bs, bs->open_flags); 1454 node_name = qemu_opt_get(opts, "node-name"); 1455 1456 assert(!drv->bdrv_file_open || file == NULL); 1457 ret = bdrv_open_driver(bs, drv, node_name, options, open_flags, errp); 1458 if (ret < 0) { 1459 goto fail_opts; 1460 } 1461 1462 qemu_opts_del(opts); 1463 return 0; 1464 1465 fail_opts: 1466 qemu_opts_del(opts); 1467 return ret; 1468 } 1469 1470 static QDict *parse_json_filename(const char *filename, Error **errp) 1471 { 1472 QObject *options_obj; 1473 QDict *options; 1474 int ret; 1475 1476 ret = strstart(filename, "json:", &filename); 1477 assert(ret); 1478 1479 options_obj = qobject_from_json(filename, errp); 1480 if (!options_obj) { 1481 error_prepend(errp, "Could not parse the JSON options: "); 1482 return NULL; 1483 } 1484 1485 options = qobject_to(QDict, options_obj); 1486 if (!options) { 1487 qobject_unref(options_obj); 1488 error_setg(errp, "Invalid JSON object given"); 1489 return NULL; 1490 } 1491 1492 qdict_flatten(options); 1493 1494 return options; 1495 } 1496 1497 static void parse_json_protocol(QDict *options, const char **pfilename, 1498 Error **errp) 1499 { 1500 QDict *json_options; 1501 Error *local_err = NULL; 1502 1503 /* Parse json: pseudo-protocol */ 1504 if (!*pfilename || !g_str_has_prefix(*pfilename, "json:")) { 1505 return; 1506 } 1507 1508 json_options = parse_json_filename(*pfilename, &local_err); 1509 if (local_err) { 1510 error_propagate(errp, local_err); 1511 return; 1512 } 1513 1514 /* Options given in the filename have lower priority than options 1515 * specified directly */ 1516 qdict_join(options, json_options, false); 1517 qobject_unref(json_options); 1518 *pfilename = NULL; 1519 } 1520 1521 /* 1522 * Fills in default options for opening images and converts the legacy 1523 * filename/flags pair to option QDict entries. 1524 * The BDRV_O_PROTOCOL flag in *flags will be set or cleared accordingly if a 1525 * block driver has been specified explicitly. 1526 */ 1527 static int bdrv_fill_options(QDict **options, const char *filename, 1528 int *flags, Error **errp) 1529 { 1530 const char *drvname; 1531 bool protocol = *flags & BDRV_O_PROTOCOL; 1532 bool parse_filename = false; 1533 BlockDriver *drv = NULL; 1534 Error *local_err = NULL; 1535 1536 /* 1537 * Caution: while qdict_get_try_str() is fine, getting non-string 1538 * types would require more care. When @options come from 1539 * -blockdev or blockdev_add, its members are typed according to 1540 * the QAPI schema, but when they come from -drive, they're all 1541 * QString. 1542 */ 1543 drvname = qdict_get_try_str(*options, "driver"); 1544 if (drvname) { 1545 drv = bdrv_find_format(drvname); 1546 if (!drv) { 1547 error_setg(errp, "Unknown driver '%s'", drvname); 1548 return -ENOENT; 1549 } 1550 /* If the user has explicitly specified the driver, this choice should 1551 * override the BDRV_O_PROTOCOL flag */ 1552 protocol = drv->bdrv_file_open; 1553 } 1554 1555 if (protocol) { 1556 *flags |= BDRV_O_PROTOCOL; 1557 } else { 1558 *flags &= ~BDRV_O_PROTOCOL; 1559 } 1560 1561 /* Translate cache options from flags into options */ 1562 update_options_from_flags(*options, *flags); 1563 1564 /* Fetch the file name from the options QDict if necessary */ 1565 if (protocol && filename) { 1566 if (!qdict_haskey(*options, "filename")) { 1567 qdict_put_str(*options, "filename", filename); 1568 parse_filename = true; 1569 } else { 1570 error_setg(errp, "Can't specify 'file' and 'filename' options at " 1571 "the same time"); 1572 return -EINVAL; 1573 } 1574 } 1575 1576 /* Find the right block driver */ 1577 /* See cautionary note on accessing @options above */ 1578 filename = qdict_get_try_str(*options, "filename"); 1579 1580 if (!drvname && protocol) { 1581 if (filename) { 1582 drv = bdrv_find_protocol(filename, parse_filename, errp); 1583 if (!drv) { 1584 return -EINVAL; 1585 } 1586 1587 drvname = drv->format_name; 1588 qdict_put_str(*options, "driver", drvname); 1589 } else { 1590 error_setg(errp, "Must specify either driver or file"); 1591 return -EINVAL; 1592 } 1593 } 1594 1595 assert(drv || !protocol); 1596 1597 /* Driver-specific filename parsing */ 1598 if (drv && drv->bdrv_parse_filename && parse_filename) { 1599 drv->bdrv_parse_filename(filename, *options, &local_err); 1600 if (local_err) { 1601 error_propagate(errp, local_err); 1602 return -EINVAL; 1603 } 1604 1605 if (!drv->bdrv_needs_filename) { 1606 qdict_del(*options, "filename"); 1607 } 1608 } 1609 1610 return 0; 1611 } 1612 1613 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, 1614 uint64_t perm, uint64_t shared, 1615 GSList *ignore_children, Error **errp); 1616 static void bdrv_child_abort_perm_update(BdrvChild *c); 1617 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared); 1618 1619 typedef struct BlockReopenQueueEntry { 1620 bool prepared; 1621 BDRVReopenState state; 1622 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; 1623 } BlockReopenQueueEntry; 1624 1625 /* 1626 * Return the flags that @bs will have after the reopens in @q have 1627 * successfully completed. If @q is NULL (or @bs is not contained in @q), 1628 * return the current flags. 1629 */ 1630 static int bdrv_reopen_get_flags(BlockReopenQueue *q, BlockDriverState *bs) 1631 { 1632 BlockReopenQueueEntry *entry; 1633 1634 if (q != NULL) { 1635 QSIMPLEQ_FOREACH(entry, q, entry) { 1636 if (entry->state.bs == bs) { 1637 return entry->state.flags; 1638 } 1639 } 1640 } 1641 1642 return bs->open_flags; 1643 } 1644 1645 /* Returns whether the image file can be written to after the reopen queue @q 1646 * has been successfully applied, or right now if @q is NULL. */ 1647 static bool bdrv_is_writable_after_reopen(BlockDriverState *bs, 1648 BlockReopenQueue *q) 1649 { 1650 int flags = bdrv_reopen_get_flags(q, bs); 1651 1652 return (flags & (BDRV_O_RDWR | BDRV_O_INACTIVE)) == BDRV_O_RDWR; 1653 } 1654 1655 /* 1656 * Return whether the BDS can be written to. This is not necessarily 1657 * the same as !bdrv_is_read_only(bs), as inactivated images may not 1658 * be written to but do not count as read-only images. 1659 */ 1660 bool bdrv_is_writable(BlockDriverState *bs) 1661 { 1662 return bdrv_is_writable_after_reopen(bs, NULL); 1663 } 1664 1665 static void bdrv_child_perm(BlockDriverState *bs, BlockDriverState *child_bs, 1666 BdrvChild *c, const BdrvChildRole *role, 1667 BlockReopenQueue *reopen_queue, 1668 uint64_t parent_perm, uint64_t parent_shared, 1669 uint64_t *nperm, uint64_t *nshared) 1670 { 1671 if (bs->drv && bs->drv->bdrv_child_perm) { 1672 bs->drv->bdrv_child_perm(bs, c, role, reopen_queue, 1673 parent_perm, parent_shared, 1674 nperm, nshared); 1675 } 1676 /* TODO Take force_share from reopen_queue */ 1677 if (child_bs && child_bs->force_share) { 1678 *nshared = BLK_PERM_ALL; 1679 } 1680 } 1681 1682 /* 1683 * Check whether permissions on this node can be changed in a way that 1684 * @cumulative_perms and @cumulative_shared_perms are the new cumulative 1685 * permissions of all its parents. This involves checking whether all necessary 1686 * permission changes to child nodes can be performed. 1687 * 1688 * A call to this function must always be followed by a call to bdrv_set_perm() 1689 * or bdrv_abort_perm_update(). 1690 */ 1691 static int bdrv_check_perm(BlockDriverState *bs, BlockReopenQueue *q, 1692 uint64_t cumulative_perms, 1693 uint64_t cumulative_shared_perms, 1694 GSList *ignore_children, Error **errp) 1695 { 1696 BlockDriver *drv = bs->drv; 1697 BdrvChild *c; 1698 int ret; 1699 1700 /* Write permissions never work with read-only images */ 1701 if ((cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) && 1702 !bdrv_is_writable_after_reopen(bs, q)) 1703 { 1704 error_setg(errp, "Block node is read-only"); 1705 return -EPERM; 1706 } 1707 1708 /* Check this node */ 1709 if (!drv) { 1710 return 0; 1711 } 1712 1713 if (drv->bdrv_check_perm) { 1714 return drv->bdrv_check_perm(bs, cumulative_perms, 1715 cumulative_shared_perms, errp); 1716 } 1717 1718 /* Drivers that never have children can omit .bdrv_child_perm() */ 1719 if (!drv->bdrv_child_perm) { 1720 assert(QLIST_EMPTY(&bs->children)); 1721 return 0; 1722 } 1723 1724 /* Check all children */ 1725 QLIST_FOREACH(c, &bs->children, next) { 1726 uint64_t cur_perm, cur_shared; 1727 bdrv_child_perm(bs, c->bs, c, c->role, q, 1728 cumulative_perms, cumulative_shared_perms, 1729 &cur_perm, &cur_shared); 1730 ret = bdrv_child_check_perm(c, q, cur_perm, cur_shared, 1731 ignore_children, errp); 1732 if (ret < 0) { 1733 return ret; 1734 } 1735 } 1736 1737 return 0; 1738 } 1739 1740 /* 1741 * Notifies drivers that after a previous bdrv_check_perm() call, the 1742 * permission update is not performed and any preparations made for it (e.g. 1743 * taken file locks) need to be undone. 1744 * 1745 * This function recursively notifies all child nodes. 1746 */ 1747 static void bdrv_abort_perm_update(BlockDriverState *bs) 1748 { 1749 BlockDriver *drv = bs->drv; 1750 BdrvChild *c; 1751 1752 if (!drv) { 1753 return; 1754 } 1755 1756 if (drv->bdrv_abort_perm_update) { 1757 drv->bdrv_abort_perm_update(bs); 1758 } 1759 1760 QLIST_FOREACH(c, &bs->children, next) { 1761 bdrv_child_abort_perm_update(c); 1762 } 1763 } 1764 1765 static void bdrv_set_perm(BlockDriverState *bs, uint64_t cumulative_perms, 1766 uint64_t cumulative_shared_perms) 1767 { 1768 BlockDriver *drv = bs->drv; 1769 BdrvChild *c; 1770 1771 if (!drv) { 1772 return; 1773 } 1774 1775 /* Update this node */ 1776 if (drv->bdrv_set_perm) { 1777 drv->bdrv_set_perm(bs, cumulative_perms, cumulative_shared_perms); 1778 } 1779 1780 /* Drivers that never have children can omit .bdrv_child_perm() */ 1781 if (!drv->bdrv_child_perm) { 1782 assert(QLIST_EMPTY(&bs->children)); 1783 return; 1784 } 1785 1786 /* Update all children */ 1787 QLIST_FOREACH(c, &bs->children, next) { 1788 uint64_t cur_perm, cur_shared; 1789 bdrv_child_perm(bs, c->bs, c, c->role, NULL, 1790 cumulative_perms, cumulative_shared_perms, 1791 &cur_perm, &cur_shared); 1792 bdrv_child_set_perm(c, cur_perm, cur_shared); 1793 } 1794 } 1795 1796 static void bdrv_get_cumulative_perm(BlockDriverState *bs, uint64_t *perm, 1797 uint64_t *shared_perm) 1798 { 1799 BdrvChild *c; 1800 uint64_t cumulative_perms = 0; 1801 uint64_t cumulative_shared_perms = BLK_PERM_ALL; 1802 1803 QLIST_FOREACH(c, &bs->parents, next_parent) { 1804 cumulative_perms |= c->perm; 1805 cumulative_shared_perms &= c->shared_perm; 1806 } 1807 1808 *perm = cumulative_perms; 1809 *shared_perm = cumulative_shared_perms; 1810 } 1811 1812 static char *bdrv_child_user_desc(BdrvChild *c) 1813 { 1814 if (c->role->get_parent_desc) { 1815 return c->role->get_parent_desc(c); 1816 } 1817 1818 return g_strdup("another user"); 1819 } 1820 1821 char *bdrv_perm_names(uint64_t perm) 1822 { 1823 struct perm_name { 1824 uint64_t perm; 1825 const char *name; 1826 } permissions[] = { 1827 { BLK_PERM_CONSISTENT_READ, "consistent read" }, 1828 { BLK_PERM_WRITE, "write" }, 1829 { BLK_PERM_WRITE_UNCHANGED, "write unchanged" }, 1830 { BLK_PERM_RESIZE, "resize" }, 1831 { BLK_PERM_GRAPH_MOD, "change children" }, 1832 { 0, NULL } 1833 }; 1834 1835 char *result = g_strdup(""); 1836 struct perm_name *p; 1837 1838 for (p = permissions; p->name; p++) { 1839 if (perm & p->perm) { 1840 char *old = result; 1841 result = g_strdup_printf("%s%s%s", old, *old ? ", " : "", p->name); 1842 g_free(old); 1843 } 1844 } 1845 1846 return result; 1847 } 1848 1849 /* 1850 * Checks whether a new reference to @bs can be added if the new user requires 1851 * @new_used_perm/@new_shared_perm as its permissions. If @ignore_children is 1852 * set, the BdrvChild objects in this list are ignored in the calculations; 1853 * this allows checking permission updates for an existing reference. 1854 * 1855 * Needs to be followed by a call to either bdrv_set_perm() or 1856 * bdrv_abort_perm_update(). */ 1857 static int bdrv_check_update_perm(BlockDriverState *bs, BlockReopenQueue *q, 1858 uint64_t new_used_perm, 1859 uint64_t new_shared_perm, 1860 GSList *ignore_children, Error **errp) 1861 { 1862 BdrvChild *c; 1863 uint64_t cumulative_perms = new_used_perm; 1864 uint64_t cumulative_shared_perms = new_shared_perm; 1865 1866 /* There is no reason why anyone couldn't tolerate write_unchanged */ 1867 assert(new_shared_perm & BLK_PERM_WRITE_UNCHANGED); 1868 1869 QLIST_FOREACH(c, &bs->parents, next_parent) { 1870 if (g_slist_find(ignore_children, c)) { 1871 continue; 1872 } 1873 1874 if ((new_used_perm & c->shared_perm) != new_used_perm) { 1875 char *user = bdrv_child_user_desc(c); 1876 char *perm_names = bdrv_perm_names(new_used_perm & ~c->shared_perm); 1877 error_setg(errp, "Conflicts with use by %s as '%s', which does not " 1878 "allow '%s' on %s", 1879 user, c->name, perm_names, bdrv_get_node_name(c->bs)); 1880 g_free(user); 1881 g_free(perm_names); 1882 return -EPERM; 1883 } 1884 1885 if ((c->perm & new_shared_perm) != c->perm) { 1886 char *user = bdrv_child_user_desc(c); 1887 char *perm_names = bdrv_perm_names(c->perm & ~new_shared_perm); 1888 error_setg(errp, "Conflicts with use by %s as '%s', which uses " 1889 "'%s' on %s", 1890 user, c->name, perm_names, bdrv_get_node_name(c->bs)); 1891 g_free(user); 1892 g_free(perm_names); 1893 return -EPERM; 1894 } 1895 1896 cumulative_perms |= c->perm; 1897 cumulative_shared_perms &= c->shared_perm; 1898 } 1899 1900 return bdrv_check_perm(bs, q, cumulative_perms, cumulative_shared_perms, 1901 ignore_children, errp); 1902 } 1903 1904 /* Needs to be followed by a call to either bdrv_child_set_perm() or 1905 * bdrv_child_abort_perm_update(). */ 1906 static int bdrv_child_check_perm(BdrvChild *c, BlockReopenQueue *q, 1907 uint64_t perm, uint64_t shared, 1908 GSList *ignore_children, Error **errp) 1909 { 1910 int ret; 1911 1912 ignore_children = g_slist_prepend(g_slist_copy(ignore_children), c); 1913 ret = bdrv_check_update_perm(c->bs, q, perm, shared, ignore_children, errp); 1914 g_slist_free(ignore_children); 1915 1916 return ret; 1917 } 1918 1919 static void bdrv_child_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared) 1920 { 1921 uint64_t cumulative_perms, cumulative_shared_perms; 1922 1923 c->perm = perm; 1924 c->shared_perm = shared; 1925 1926 bdrv_get_cumulative_perm(c->bs, &cumulative_perms, 1927 &cumulative_shared_perms); 1928 bdrv_set_perm(c->bs, cumulative_perms, cumulative_shared_perms); 1929 } 1930 1931 static void bdrv_child_abort_perm_update(BdrvChild *c) 1932 { 1933 bdrv_abort_perm_update(c->bs); 1934 } 1935 1936 int bdrv_child_try_set_perm(BdrvChild *c, uint64_t perm, uint64_t shared, 1937 Error **errp) 1938 { 1939 int ret; 1940 1941 ret = bdrv_child_check_perm(c, NULL, perm, shared, NULL, errp); 1942 if (ret < 0) { 1943 bdrv_child_abort_perm_update(c); 1944 return ret; 1945 } 1946 1947 bdrv_child_set_perm(c, perm, shared); 1948 1949 return 0; 1950 } 1951 1952 void bdrv_filter_default_perms(BlockDriverState *bs, BdrvChild *c, 1953 const BdrvChildRole *role, 1954 BlockReopenQueue *reopen_queue, 1955 uint64_t perm, uint64_t shared, 1956 uint64_t *nperm, uint64_t *nshared) 1957 { 1958 if (c == NULL) { 1959 *nperm = perm & DEFAULT_PERM_PASSTHROUGH; 1960 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | DEFAULT_PERM_UNCHANGED; 1961 return; 1962 } 1963 1964 *nperm = (perm & DEFAULT_PERM_PASSTHROUGH) | 1965 (c->perm & DEFAULT_PERM_UNCHANGED); 1966 *nshared = (shared & DEFAULT_PERM_PASSTHROUGH) | 1967 (c->shared_perm & DEFAULT_PERM_UNCHANGED); 1968 } 1969 1970 void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c, 1971 const BdrvChildRole *role, 1972 BlockReopenQueue *reopen_queue, 1973 uint64_t perm, uint64_t shared, 1974 uint64_t *nperm, uint64_t *nshared) 1975 { 1976 bool backing = (role == &child_backing); 1977 assert(role == &child_backing || role == &child_file); 1978 1979 if (!backing) { 1980 int flags = bdrv_reopen_get_flags(reopen_queue, bs); 1981 1982 /* Apart from the modifications below, the same permissions are 1983 * forwarded and left alone as for filters */ 1984 bdrv_filter_default_perms(bs, c, role, reopen_queue, perm, shared, 1985 &perm, &shared); 1986 1987 /* Format drivers may touch metadata even if the guest doesn't write */ 1988 if (bdrv_is_writable_after_reopen(bs, reopen_queue)) { 1989 perm |= BLK_PERM_WRITE | BLK_PERM_RESIZE; 1990 } 1991 1992 /* bs->file always needs to be consistent because of the metadata. We 1993 * can never allow other users to resize or write to it. */ 1994 if (!(flags & BDRV_O_NO_IO)) { 1995 perm |= BLK_PERM_CONSISTENT_READ; 1996 } 1997 shared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); 1998 } else { 1999 /* We want consistent read from backing files if the parent needs it. 2000 * No other operations are performed on backing files. */ 2001 perm &= BLK_PERM_CONSISTENT_READ; 2002 2003 /* If the parent can deal with changing data, we're okay with a 2004 * writable and resizable backing file. */ 2005 /* TODO Require !(perm & BLK_PERM_CONSISTENT_READ), too? */ 2006 if (shared & BLK_PERM_WRITE) { 2007 shared = BLK_PERM_WRITE | BLK_PERM_RESIZE; 2008 } else { 2009 shared = 0; 2010 } 2011 2012 shared |= BLK_PERM_CONSISTENT_READ | BLK_PERM_GRAPH_MOD | 2013 BLK_PERM_WRITE_UNCHANGED; 2014 } 2015 2016 if (bs->open_flags & BDRV_O_INACTIVE) { 2017 shared |= BLK_PERM_WRITE | BLK_PERM_RESIZE; 2018 } 2019 2020 *nperm = perm; 2021 *nshared = shared; 2022 } 2023 2024 static void bdrv_replace_child_noperm(BdrvChild *child, 2025 BlockDriverState *new_bs) 2026 { 2027 BlockDriverState *old_bs = child->bs; 2028 int i; 2029 2030 if (old_bs && new_bs) { 2031 assert(bdrv_get_aio_context(old_bs) == bdrv_get_aio_context(new_bs)); 2032 } 2033 if (old_bs) { 2034 /* Detach first so that the recursive drain sections coming from @child 2035 * are already gone and we only end the drain sections that came from 2036 * elsewhere. */ 2037 if (child->role->detach) { 2038 child->role->detach(child); 2039 } 2040 if (old_bs->quiesce_counter && child->role->drained_end) { 2041 int num = old_bs->quiesce_counter; 2042 if (child->role->parent_is_bds) { 2043 num -= bdrv_drain_all_count; 2044 } 2045 assert(num >= 0); 2046 for (i = 0; i < num; i++) { 2047 child->role->drained_end(child); 2048 } 2049 } 2050 QLIST_REMOVE(child, next_parent); 2051 } 2052 2053 child->bs = new_bs; 2054 2055 if (new_bs) { 2056 QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); 2057 if (new_bs->quiesce_counter && child->role->drained_begin) { 2058 int num = new_bs->quiesce_counter; 2059 if (child->role->parent_is_bds) { 2060 num -= bdrv_drain_all_count; 2061 } 2062 assert(num >= 0); 2063 for (i = 0; i < num; i++) { 2064 bdrv_parent_drained_begin_single(child, true); 2065 } 2066 } 2067 2068 /* Attach only after starting new drained sections, so that recursive 2069 * drain sections coming from @child don't get an extra .drained_begin 2070 * callback. */ 2071 if (child->role->attach) { 2072 child->role->attach(child); 2073 } 2074 } 2075 } 2076 2077 /* 2078 * Updates @child to change its reference to point to @new_bs, including 2079 * checking and applying the necessary permisson updates both to the old node 2080 * and to @new_bs. 2081 * 2082 * NULL is passed as @new_bs for removing the reference before freeing @child. 2083 * 2084 * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this 2085 * function uses bdrv_set_perm() to update the permissions according to the new 2086 * reference that @new_bs gets. 2087 */ 2088 static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) 2089 { 2090 BlockDriverState *old_bs = child->bs; 2091 uint64_t perm, shared_perm; 2092 2093 bdrv_replace_child_noperm(child, new_bs); 2094 2095 if (old_bs) { 2096 /* Update permissions for old node. This is guaranteed to succeed 2097 * because we're just taking a parent away, so we're loosening 2098 * restrictions. */ 2099 bdrv_get_cumulative_perm(old_bs, &perm, &shared_perm); 2100 bdrv_check_perm(old_bs, NULL, perm, shared_perm, NULL, &error_abort); 2101 bdrv_set_perm(old_bs, perm, shared_perm); 2102 } 2103 2104 if (new_bs) { 2105 bdrv_get_cumulative_perm(new_bs, &perm, &shared_perm); 2106 bdrv_set_perm(new_bs, perm, shared_perm); 2107 } 2108 } 2109 2110 BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, 2111 const char *child_name, 2112 const BdrvChildRole *child_role, 2113 uint64_t perm, uint64_t shared_perm, 2114 void *opaque, Error **errp) 2115 { 2116 BdrvChild *child; 2117 int ret; 2118 2119 ret = bdrv_check_update_perm(child_bs, NULL, perm, shared_perm, NULL, errp); 2120 if (ret < 0) { 2121 bdrv_abort_perm_update(child_bs); 2122 return NULL; 2123 } 2124 2125 child = g_new(BdrvChild, 1); 2126 *child = (BdrvChild) { 2127 .bs = NULL, 2128 .name = g_strdup(child_name), 2129 .role = child_role, 2130 .perm = perm, 2131 .shared_perm = shared_perm, 2132 .opaque = opaque, 2133 }; 2134 2135 /* This performs the matching bdrv_set_perm() for the above check. */ 2136 bdrv_replace_child(child, child_bs); 2137 2138 return child; 2139 } 2140 2141 BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, 2142 BlockDriverState *child_bs, 2143 const char *child_name, 2144 const BdrvChildRole *child_role, 2145 Error **errp) 2146 { 2147 BdrvChild *child; 2148 uint64_t perm, shared_perm; 2149 2150 bdrv_get_cumulative_perm(parent_bs, &perm, &shared_perm); 2151 2152 assert(parent_bs->drv); 2153 assert(bdrv_get_aio_context(parent_bs) == bdrv_get_aio_context(child_bs)); 2154 bdrv_child_perm(parent_bs, child_bs, NULL, child_role, NULL, 2155 perm, shared_perm, &perm, &shared_perm); 2156 2157 child = bdrv_root_attach_child(child_bs, child_name, child_role, 2158 perm, shared_perm, parent_bs, errp); 2159 if (child == NULL) { 2160 return NULL; 2161 } 2162 2163 QLIST_INSERT_HEAD(&parent_bs->children, child, next); 2164 return child; 2165 } 2166 2167 static void bdrv_detach_child(BdrvChild *child) 2168 { 2169 if (child->next.le_prev) { 2170 QLIST_REMOVE(child, next); 2171 child->next.le_prev = NULL; 2172 } 2173 2174 bdrv_replace_child(child, NULL); 2175 2176 g_free(child->name); 2177 g_free(child); 2178 } 2179 2180 void bdrv_root_unref_child(BdrvChild *child) 2181 { 2182 BlockDriverState *child_bs; 2183 2184 child_bs = child->bs; 2185 bdrv_detach_child(child); 2186 bdrv_unref(child_bs); 2187 } 2188 2189 void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) 2190 { 2191 if (child == NULL) { 2192 return; 2193 } 2194 2195 if (child->bs->inherits_from == parent) { 2196 BdrvChild *c; 2197 2198 /* Remove inherits_from only when the last reference between parent and 2199 * child->bs goes away. */ 2200 QLIST_FOREACH(c, &parent->children, next) { 2201 if (c != child && c->bs == child->bs) { 2202 break; 2203 } 2204 } 2205 if (c == NULL) { 2206 child->bs->inherits_from = NULL; 2207 } 2208 } 2209 2210 bdrv_root_unref_child(child); 2211 } 2212 2213 2214 static void bdrv_parent_cb_change_media(BlockDriverState *bs, bool load) 2215 { 2216 BdrvChild *c; 2217 QLIST_FOREACH(c, &bs->parents, next_parent) { 2218 if (c->role->change_media) { 2219 c->role->change_media(c, load); 2220 } 2221 } 2222 } 2223 2224 /* 2225 * Sets the backing file link of a BDS. A new reference is created; callers 2226 * which don't need their own reference any more must call bdrv_unref(). 2227 */ 2228 void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, 2229 Error **errp) 2230 { 2231 if (backing_hd) { 2232 bdrv_ref(backing_hd); 2233 } 2234 2235 if (bs->backing) { 2236 bdrv_unref_child(bs, bs->backing); 2237 } 2238 2239 if (!backing_hd) { 2240 bs->backing = NULL; 2241 goto out; 2242 } 2243 2244 bs->backing = bdrv_attach_child(bs, backing_hd, "backing", &child_backing, 2245 errp); 2246 if (!bs->backing) { 2247 bdrv_unref(backing_hd); 2248 } 2249 2250 bdrv_refresh_filename(bs); 2251 2252 out: 2253 bdrv_refresh_limits(bs, NULL); 2254 } 2255 2256 /* 2257 * Opens the backing file for a BlockDriverState if not yet open 2258 * 2259 * bdref_key specifies the key for the image's BlockdevRef in the options QDict. 2260 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict 2261 * itself, all options starting with "${bdref_key}." are considered part of the 2262 * BlockdevRef. 2263 * 2264 * TODO Can this be unified with bdrv_open_image()? 2265 */ 2266 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, 2267 const char *bdref_key, Error **errp) 2268 { 2269 char *backing_filename = g_malloc0(PATH_MAX); 2270 char *bdref_key_dot; 2271 const char *reference = NULL; 2272 int ret = 0; 2273 BlockDriverState *backing_hd; 2274 QDict *options; 2275 QDict *tmp_parent_options = NULL; 2276 Error *local_err = NULL; 2277 2278 if (bs->backing != NULL) { 2279 goto free_exit; 2280 } 2281 2282 /* NULL means an empty set of options */ 2283 if (parent_options == NULL) { 2284 tmp_parent_options = qdict_new(); 2285 parent_options = tmp_parent_options; 2286 } 2287 2288 bs->open_flags &= ~BDRV_O_NO_BACKING; 2289 2290 bdref_key_dot = g_strdup_printf("%s.", bdref_key); 2291 qdict_extract_subqdict(parent_options, &options, bdref_key_dot); 2292 g_free(bdref_key_dot); 2293 2294 /* 2295 * Caution: while qdict_get_try_str() is fine, getting non-string 2296 * types would require more care. When @parent_options come from 2297 * -blockdev or blockdev_add, its members are typed according to 2298 * the QAPI schema, but when they come from -drive, they're all 2299 * QString. 2300 */ 2301 reference = qdict_get_try_str(parent_options, bdref_key); 2302 if (reference || qdict_haskey(options, "file.filename")) { 2303 backing_filename[0] = '\0'; 2304 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { 2305 qobject_unref(options); 2306 goto free_exit; 2307 } else { 2308 bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX, 2309 &local_err); 2310 if (local_err) { 2311 ret = -EINVAL; 2312 error_propagate(errp, local_err); 2313 qobject_unref(options); 2314 goto free_exit; 2315 } 2316 } 2317 2318 if (!bs->drv || !bs->drv->supports_backing) { 2319 ret = -EINVAL; 2320 error_setg(errp, "Driver doesn't support backing files"); 2321 qobject_unref(options); 2322 goto free_exit; 2323 } 2324 2325 if (!reference && 2326 bs->backing_format[0] != '\0' && !qdict_haskey(options, "driver")) { 2327 qdict_put_str(options, "driver", bs->backing_format); 2328 } 2329 2330 backing_hd = bdrv_open_inherit(*backing_filename ? backing_filename : NULL, 2331 reference, options, 0, bs, &child_backing, 2332 errp); 2333 if (!backing_hd) { 2334 bs->open_flags |= BDRV_O_NO_BACKING; 2335 error_prepend(errp, "Could not open backing file: "); 2336 ret = -EINVAL; 2337 goto free_exit; 2338 } 2339 bdrv_set_aio_context(backing_hd, bdrv_get_aio_context(bs)); 2340 2341 /* Hook up the backing file link; drop our reference, bs owns the 2342 * backing_hd reference now */ 2343 bdrv_set_backing_hd(bs, backing_hd, &local_err); 2344 bdrv_unref(backing_hd); 2345 if (local_err) { 2346 error_propagate(errp, local_err); 2347 ret = -EINVAL; 2348 goto free_exit; 2349 } 2350 2351 qdict_del(parent_options, bdref_key); 2352 2353 free_exit: 2354 g_free(backing_filename); 2355 qobject_unref(tmp_parent_options); 2356 return ret; 2357 } 2358 2359 static BlockDriverState * 2360 bdrv_open_child_bs(const char *filename, QDict *options, const char *bdref_key, 2361 BlockDriverState *parent, const BdrvChildRole *child_role, 2362 bool allow_none, Error **errp) 2363 { 2364 BlockDriverState *bs = NULL; 2365 QDict *image_options; 2366 char *bdref_key_dot; 2367 const char *reference; 2368 2369 assert(child_role != NULL); 2370 2371 bdref_key_dot = g_strdup_printf("%s.", bdref_key); 2372 qdict_extract_subqdict(options, &image_options, bdref_key_dot); 2373 g_free(bdref_key_dot); 2374 2375 /* 2376 * Caution: while qdict_get_try_str() is fine, getting non-string 2377 * types would require more care. When @options come from 2378 * -blockdev or blockdev_add, its members are typed according to 2379 * the QAPI schema, but when they come from -drive, they're all 2380 * QString. 2381 */ 2382 reference = qdict_get_try_str(options, bdref_key); 2383 if (!filename && !reference && !qdict_size(image_options)) { 2384 if (!allow_none) { 2385 error_setg(errp, "A block device must be specified for \"%s\"", 2386 bdref_key); 2387 } 2388 qobject_unref(image_options); 2389 goto done; 2390 } 2391 2392 bs = bdrv_open_inherit(filename, reference, image_options, 0, 2393 parent, child_role, errp); 2394 if (!bs) { 2395 goto done; 2396 } 2397 2398 done: 2399 qdict_del(options, bdref_key); 2400 return bs; 2401 } 2402 2403 /* 2404 * Opens a disk image whose options are given as BlockdevRef in another block 2405 * device's options. 2406 * 2407 * If allow_none is true, no image will be opened if filename is false and no 2408 * BlockdevRef is given. NULL will be returned, but errp remains unset. 2409 * 2410 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict. 2411 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict 2412 * itself, all options starting with "${bdref_key}." are considered part of the 2413 * BlockdevRef. 2414 * 2415 * The BlockdevRef will be removed from the options QDict. 2416 */ 2417 BdrvChild *bdrv_open_child(const char *filename, 2418 QDict *options, const char *bdref_key, 2419 BlockDriverState *parent, 2420 const BdrvChildRole *child_role, 2421 bool allow_none, Error **errp) 2422 { 2423 BdrvChild *c; 2424 BlockDriverState *bs; 2425 2426 bs = bdrv_open_child_bs(filename, options, bdref_key, parent, child_role, 2427 allow_none, errp); 2428 if (bs == NULL) { 2429 return NULL; 2430 } 2431 2432 c = bdrv_attach_child(parent, bs, bdref_key, child_role, errp); 2433 if (!c) { 2434 bdrv_unref(bs); 2435 return NULL; 2436 } 2437 2438 return c; 2439 } 2440 2441 /* TODO Future callers may need to specify parent/child_role in order for 2442 * option inheritance to work. Existing callers use it for the root node. */ 2443 BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp) 2444 { 2445 BlockDriverState *bs = NULL; 2446 Error *local_err = NULL; 2447 QObject *obj = NULL; 2448 QDict *qdict = NULL; 2449 const char *reference = NULL; 2450 Visitor *v = NULL; 2451 2452 if (ref->type == QTYPE_QSTRING) { 2453 reference = ref->u.reference; 2454 } else { 2455 BlockdevOptions *options = &ref->u.definition; 2456 assert(ref->type == QTYPE_QDICT); 2457 2458 v = qobject_output_visitor_new(&obj); 2459 visit_type_BlockdevOptions(v, NULL, &options, &local_err); 2460 if (local_err) { 2461 error_propagate(errp, local_err); 2462 goto fail; 2463 } 2464 visit_complete(v, &obj); 2465 2466 qdict = qobject_to(QDict, obj); 2467 qdict_flatten(qdict); 2468 2469 /* bdrv_open_inherit() defaults to the values in bdrv_flags (for 2470 * compatibility with other callers) rather than what we want as the 2471 * real defaults. Apply the defaults here instead. */ 2472 qdict_set_default_str(qdict, BDRV_OPT_CACHE_DIRECT, "off"); 2473 qdict_set_default_str(qdict, BDRV_OPT_CACHE_NO_FLUSH, "off"); 2474 qdict_set_default_str(qdict, BDRV_OPT_READ_ONLY, "off"); 2475 } 2476 2477 bs = bdrv_open_inherit(NULL, reference, qdict, 0, NULL, NULL, errp); 2478 obj = NULL; 2479 2480 fail: 2481 qobject_unref(obj); 2482 visit_free(v); 2483 return bs; 2484 } 2485 2486 static BlockDriverState *bdrv_append_temp_snapshot(BlockDriverState *bs, 2487 int flags, 2488 QDict *snapshot_options, 2489 Error **errp) 2490 { 2491 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ 2492 char *tmp_filename = g_malloc0(PATH_MAX + 1); 2493 int64_t total_size; 2494 QemuOpts *opts = NULL; 2495 BlockDriverState *bs_snapshot = NULL; 2496 Error *local_err = NULL; 2497 int ret; 2498 2499 /* if snapshot, we create a temporary backing file and open it 2500 instead of opening 'filename' directly */ 2501 2502 /* Get the required size from the image */ 2503 total_size = bdrv_getlength(bs); 2504 if (total_size < 0) { 2505 error_setg_errno(errp, -total_size, "Could not get image size"); 2506 goto out; 2507 } 2508 2509 /* Create the temporary image */ 2510 ret = get_tmp_filename(tmp_filename, PATH_MAX + 1); 2511 if (ret < 0) { 2512 error_setg_errno(errp, -ret, "Could not get temporary filename"); 2513 goto out; 2514 } 2515 2516 opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, 2517 &error_abort); 2518 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort); 2519 ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp); 2520 qemu_opts_del(opts); 2521 if (ret < 0) { 2522 error_prepend(errp, "Could not create temporary overlay '%s': ", 2523 tmp_filename); 2524 goto out; 2525 } 2526 2527 /* Prepare options QDict for the temporary file */ 2528 qdict_put_str(snapshot_options, "file.driver", "file"); 2529 qdict_put_str(snapshot_options, "file.filename", tmp_filename); 2530 qdict_put_str(snapshot_options, "driver", "qcow2"); 2531 2532 bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, flags, errp); 2533 snapshot_options = NULL; 2534 if (!bs_snapshot) { 2535 goto out; 2536 } 2537 2538 /* bdrv_append() consumes a strong reference to bs_snapshot 2539 * (i.e. it will call bdrv_unref() on it) even on error, so in 2540 * order to be able to return one, we have to increase 2541 * bs_snapshot's refcount here */ 2542 bdrv_ref(bs_snapshot); 2543 bdrv_append(bs_snapshot, bs, &local_err); 2544 if (local_err) { 2545 error_propagate(errp, local_err); 2546 bs_snapshot = NULL; 2547 goto out; 2548 } 2549 2550 out: 2551 qobject_unref(snapshot_options); 2552 g_free(tmp_filename); 2553 return bs_snapshot; 2554 } 2555 2556 /* 2557 * Opens a disk image (raw, qcow2, vmdk, ...) 2558 * 2559 * options is a QDict of options to pass to the block drivers, or NULL for an 2560 * empty set of options. The reference to the QDict belongs to the block layer 2561 * after the call (even on failure), so if the caller intends to reuse the 2562 * dictionary, it needs to use qobject_ref() before calling bdrv_open. 2563 * 2564 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there. 2565 * If it is not NULL, the referenced BDS will be reused. 2566 * 2567 * The reference parameter may be used to specify an existing block device which 2568 * should be opened. If specified, neither options nor a filename may be given, 2569 * nor can an existing BDS be reused (that is, *pbs has to be NULL). 2570 */ 2571 static BlockDriverState *bdrv_open_inherit(const char *filename, 2572 const char *reference, 2573 QDict *options, int flags, 2574 BlockDriverState *parent, 2575 const BdrvChildRole *child_role, 2576 Error **errp) 2577 { 2578 int ret; 2579 BlockBackend *file = NULL; 2580 BlockDriverState *bs; 2581 BlockDriver *drv = NULL; 2582 BdrvChild *child; 2583 const char *drvname; 2584 const char *backing; 2585 Error *local_err = NULL; 2586 QDict *snapshot_options = NULL; 2587 int snapshot_flags = 0; 2588 2589 assert(!child_role || !flags); 2590 assert(!child_role == !parent); 2591 2592 if (reference) { 2593 bool options_non_empty = options ? qdict_size(options) : false; 2594 qobject_unref(options); 2595 2596 if (filename || options_non_empty) { 2597 error_setg(errp, "Cannot reference an existing block device with " 2598 "additional options or a new filename"); 2599 return NULL; 2600 } 2601 2602 bs = bdrv_lookup_bs(reference, reference, errp); 2603 if (!bs) { 2604 return NULL; 2605 } 2606 2607 bdrv_ref(bs); 2608 return bs; 2609 } 2610 2611 bs = bdrv_new(); 2612 2613 /* NULL means an empty set of options */ 2614 if (options == NULL) { 2615 options = qdict_new(); 2616 } 2617 2618 /* json: syntax counts as explicit options, as if in the QDict */ 2619 parse_json_protocol(options, &filename, &local_err); 2620 if (local_err) { 2621 goto fail; 2622 } 2623 2624 bs->explicit_options = qdict_clone_shallow(options); 2625 2626 if (child_role) { 2627 bs->inherits_from = parent; 2628 child_role->inherit_options(&flags, options, 2629 parent->open_flags, parent->options); 2630 } 2631 2632 ret = bdrv_fill_options(&options, filename, &flags, &local_err); 2633 if (local_err) { 2634 goto fail; 2635 } 2636 2637 /* 2638 * Set the BDRV_O_RDWR and BDRV_O_ALLOW_RDWR flags. 2639 * Caution: getting a boolean member of @options requires care. 2640 * When @options come from -blockdev or blockdev_add, members are 2641 * typed according to the QAPI schema, but when they come from 2642 * -drive, they're all QString. 2643 */ 2644 if (g_strcmp0(qdict_get_try_str(options, BDRV_OPT_READ_ONLY), "on") && 2645 !qdict_get_try_bool(options, BDRV_OPT_READ_ONLY, false)) { 2646 flags |= (BDRV_O_RDWR | BDRV_O_ALLOW_RDWR); 2647 } else { 2648 flags &= ~BDRV_O_RDWR; 2649 } 2650 2651 if (flags & BDRV_O_SNAPSHOT) { 2652 snapshot_options = qdict_new(); 2653 bdrv_temp_snapshot_options(&snapshot_flags, snapshot_options, 2654 flags, options); 2655 /* Let bdrv_backing_options() override "read-only" */ 2656 qdict_del(options, BDRV_OPT_READ_ONLY); 2657 bdrv_backing_options(&flags, options, flags, options); 2658 } 2659 2660 bs->open_flags = flags; 2661 bs->options = options; 2662 options = qdict_clone_shallow(options); 2663 2664 /* Find the right image format driver */ 2665 /* See cautionary note on accessing @options above */ 2666 drvname = qdict_get_try_str(options, "driver"); 2667 if (drvname) { 2668 drv = bdrv_find_format(drvname); 2669 if (!drv) { 2670 error_setg(errp, "Unknown driver: '%s'", drvname); 2671 goto fail; 2672 } 2673 } 2674 2675 assert(drvname || !(flags & BDRV_O_PROTOCOL)); 2676 2677 /* See cautionary note on accessing @options above */ 2678 backing = qdict_get_try_str(options, "backing"); 2679 if (qobject_to(QNull, qdict_get(options, "backing")) != NULL || 2680 (backing && *backing == '\0')) 2681 { 2682 if (backing) { 2683 warn_report("Use of \"backing\": \"\" is deprecated; " 2684 "use \"backing\": null instead"); 2685 } 2686 flags |= BDRV_O_NO_BACKING; 2687 qdict_del(options, "backing"); 2688 } 2689 2690 /* Open image file without format layer. This BlockBackend is only used for 2691 * probing, the block drivers will do their own bdrv_open_child() for the 2692 * same BDS, which is why we put the node name back into options. */ 2693 if ((flags & BDRV_O_PROTOCOL) == 0) { 2694 BlockDriverState *file_bs; 2695 2696 file_bs = bdrv_open_child_bs(filename, options, "file", bs, 2697 &child_file, true, &local_err); 2698 if (local_err) { 2699 goto fail; 2700 } 2701 if (file_bs != NULL) { 2702 /* Not requesting BLK_PERM_CONSISTENT_READ because we're only 2703 * looking at the header to guess the image format. This works even 2704 * in cases where a guest would not see a consistent state. */ 2705 file = blk_new(0, BLK_PERM_ALL); 2706 blk_insert_bs(file, file_bs, &local_err); 2707 bdrv_unref(file_bs); 2708 if (local_err) { 2709 goto fail; 2710 } 2711 2712 qdict_put_str(options, "file", bdrv_get_node_name(file_bs)); 2713 } 2714 } 2715 2716 /* Image format probing */ 2717 bs->probed = !drv; 2718 if (!drv && file) { 2719 ret = find_image_format(file, filename, &drv, &local_err); 2720 if (ret < 0) { 2721 goto fail; 2722 } 2723 /* 2724 * This option update would logically belong in bdrv_fill_options(), 2725 * but we first need to open bs->file for the probing to work, while 2726 * opening bs->file already requires the (mostly) final set of options 2727 * so that cache mode etc. can be inherited. 2728 * 2729 * Adding the driver later is somewhat ugly, but it's not an option 2730 * that would ever be inherited, so it's correct. We just need to make 2731 * sure to update both bs->options (which has the full effective 2732 * options for bs) and options (which has file.* already removed). 2733 */ 2734 qdict_put_str(bs->options, "driver", drv->format_name); 2735 qdict_put_str(options, "driver", drv->format_name); 2736 } else if (!drv) { 2737 error_setg(errp, "Must specify either driver or file"); 2738 goto fail; 2739 } 2740 2741 /* BDRV_O_PROTOCOL must be set iff a protocol BDS is about to be created */ 2742 assert(!!(flags & BDRV_O_PROTOCOL) == !!drv->bdrv_file_open); 2743 /* file must be NULL if a protocol BDS is about to be created 2744 * (the inverse results in an error message from bdrv_open_common()) */ 2745 assert(!(flags & BDRV_O_PROTOCOL) || !file); 2746 2747 /* Open the image */ 2748 ret = bdrv_open_common(bs, file, options, &local_err); 2749 if (ret < 0) { 2750 goto fail; 2751 } 2752 2753 if (file) { 2754 blk_unref(file); 2755 file = NULL; 2756 } 2757 2758 /* If there is a backing file, use it */ 2759 if ((flags & BDRV_O_NO_BACKING) == 0) { 2760 ret = bdrv_open_backing_file(bs, options, "backing", &local_err); 2761 if (ret < 0) { 2762 goto close_and_fail; 2763 } 2764 } 2765 2766 /* Remove all children options from bs->options and bs->explicit_options */ 2767 QLIST_FOREACH(child, &bs->children, next) { 2768 char *child_key_dot; 2769 child_key_dot = g_strdup_printf("%s.", child->name); 2770 qdict_extract_subqdict(bs->explicit_options, NULL, child_key_dot); 2771 qdict_extract_subqdict(bs->options, NULL, child_key_dot); 2772 g_free(child_key_dot); 2773 } 2774 2775 bdrv_refresh_filename(bs); 2776 2777 /* Check if any unknown options were used */ 2778 if (qdict_size(options) != 0) { 2779 const QDictEntry *entry = qdict_first(options); 2780 if (flags & BDRV_O_PROTOCOL) { 2781 error_setg(errp, "Block protocol '%s' doesn't support the option " 2782 "'%s'", drv->format_name, entry->key); 2783 } else { 2784 error_setg(errp, 2785 "Block format '%s' does not support the option '%s'", 2786 drv->format_name, entry->key); 2787 } 2788 2789 goto close_and_fail; 2790 } 2791 2792 bdrv_parent_cb_change_media(bs, true); 2793 2794 qobject_unref(options); 2795 2796 /* For snapshot=on, create a temporary qcow2 overlay. bs points to the 2797 * temporary snapshot afterwards. */ 2798 if (snapshot_flags) { 2799 BlockDriverState *snapshot_bs; 2800 snapshot_bs = bdrv_append_temp_snapshot(bs, snapshot_flags, 2801 snapshot_options, &local_err); 2802 snapshot_options = NULL; 2803 if (local_err) { 2804 goto close_and_fail; 2805 } 2806 /* We are not going to return bs but the overlay on top of it 2807 * (snapshot_bs); thus, we have to drop the strong reference to bs 2808 * (which we obtained by calling bdrv_new()). bs will not be deleted, 2809 * though, because the overlay still has a reference to it. */ 2810 bdrv_unref(bs); 2811 bs = snapshot_bs; 2812 } 2813 2814 return bs; 2815 2816 fail: 2817 blk_unref(file); 2818 qobject_unref(snapshot_options); 2819 qobject_unref(bs->explicit_options); 2820 qobject_unref(bs->options); 2821 qobject_unref(options); 2822 bs->options = NULL; 2823 bs->explicit_options = NULL; 2824 bdrv_unref(bs); 2825 error_propagate(errp, local_err); 2826 return NULL; 2827 2828 close_and_fail: 2829 bdrv_unref(bs); 2830 qobject_unref(snapshot_options); 2831 qobject_unref(options); 2832 error_propagate(errp, local_err); 2833 return NULL; 2834 } 2835 2836 BlockDriverState *bdrv_open(const char *filename, const char *reference, 2837 QDict *options, int flags, Error **errp) 2838 { 2839 return bdrv_open_inherit(filename, reference, options, flags, NULL, 2840 NULL, errp); 2841 } 2842 2843 /* 2844 * Adds a BlockDriverState to a simple queue for an atomic, transactional 2845 * reopen of multiple devices. 2846 * 2847 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT 2848 * already performed, or alternatively may be NULL a new BlockReopenQueue will 2849 * be created and initialized. This newly created BlockReopenQueue should be 2850 * passed back in for subsequent calls that are intended to be of the same 2851 * atomic 'set'. 2852 * 2853 * bs is the BlockDriverState to add to the reopen queue. 2854 * 2855 * options contains the changed options for the associated bs 2856 * (the BlockReopenQueue takes ownership) 2857 * 2858 * flags contains the open flags for the associated bs 2859 * 2860 * returns a pointer to bs_queue, which is either the newly allocated 2861 * bs_queue, or the existing bs_queue being used. 2862 * 2863 * bs must be drained between bdrv_reopen_queue() and bdrv_reopen_multiple(). 2864 */ 2865 static BlockReopenQueue *bdrv_reopen_queue_child(BlockReopenQueue *bs_queue, 2866 BlockDriverState *bs, 2867 QDict *options, 2868 int flags, 2869 const BdrvChildRole *role, 2870 QDict *parent_options, 2871 int parent_flags) 2872 { 2873 assert(bs != NULL); 2874 2875 BlockReopenQueueEntry *bs_entry; 2876 BdrvChild *child; 2877 QDict *old_options, *explicit_options; 2878 2879 /* Make sure that the caller remembered to use a drained section. This is 2880 * important to avoid graph changes between the recursive queuing here and 2881 * bdrv_reopen_multiple(). */ 2882 assert(bs->quiesce_counter > 0); 2883 2884 if (bs_queue == NULL) { 2885 bs_queue = g_new0(BlockReopenQueue, 1); 2886 QSIMPLEQ_INIT(bs_queue); 2887 } 2888 2889 if (!options) { 2890 options = qdict_new(); 2891 } 2892 2893 /* Check if this BlockDriverState is already in the queue */ 2894 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 2895 if (bs == bs_entry->state.bs) { 2896 break; 2897 } 2898 } 2899 2900 /* 2901 * Precedence of options: 2902 * 1. Explicitly passed in options (highest) 2903 * 2. Set in flags (only for top level) 2904 * 3. Retained from explicitly set options of bs 2905 * 4. Inherited from parent node 2906 * 5. Retained from effective options of bs 2907 */ 2908 2909 if (!parent_options) { 2910 /* 2911 * Any setting represented by flags is always updated. If the 2912 * corresponding QDict option is set, it takes precedence. Otherwise 2913 * the flag is translated into a QDict option. The old setting of bs is 2914 * not considered. 2915 */ 2916 update_options_from_flags(options, flags); 2917 } 2918 2919 /* Old explicitly set values (don't overwrite by inherited value) */ 2920 if (bs_entry) { 2921 old_options = qdict_clone_shallow(bs_entry->state.explicit_options); 2922 } else { 2923 old_options = qdict_clone_shallow(bs->explicit_options); 2924 } 2925 bdrv_join_options(bs, options, old_options); 2926 qobject_unref(old_options); 2927 2928 explicit_options = qdict_clone_shallow(options); 2929 2930 /* Inherit from parent node */ 2931 if (parent_options) { 2932 QemuOpts *opts; 2933 QDict *options_copy; 2934 assert(!flags); 2935 role->inherit_options(&flags, options, parent_flags, parent_options); 2936 options_copy = qdict_clone_shallow(options); 2937 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); 2938 qemu_opts_absorb_qdict(opts, options_copy, NULL); 2939 update_flags_from_options(&flags, opts); 2940 qemu_opts_del(opts); 2941 qobject_unref(options_copy); 2942 } 2943 2944 /* Old values are used for options that aren't set yet */ 2945 old_options = qdict_clone_shallow(bs->options); 2946 bdrv_join_options(bs, options, old_options); 2947 qobject_unref(old_options); 2948 2949 /* bdrv_open_inherit() sets and clears some additional flags internally */ 2950 flags &= ~BDRV_O_PROTOCOL; 2951 if (flags & BDRV_O_RDWR) { 2952 flags |= BDRV_O_ALLOW_RDWR; 2953 } 2954 2955 if (!bs_entry) { 2956 bs_entry = g_new0(BlockReopenQueueEntry, 1); 2957 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); 2958 } else { 2959 qobject_unref(bs_entry->state.options); 2960 qobject_unref(bs_entry->state.explicit_options); 2961 } 2962 2963 bs_entry->state.bs = bs; 2964 bs_entry->state.options = options; 2965 bs_entry->state.explicit_options = explicit_options; 2966 bs_entry->state.flags = flags; 2967 2968 /* This needs to be overwritten in bdrv_reopen_prepare() */ 2969 bs_entry->state.perm = UINT64_MAX; 2970 bs_entry->state.shared_perm = 0; 2971 2972 QLIST_FOREACH(child, &bs->children, next) { 2973 QDict *new_child_options; 2974 char *child_key_dot; 2975 2976 /* reopen can only change the options of block devices that were 2977 * implicitly created and inherited options. For other (referenced) 2978 * block devices, a syntax like "backing.foo" results in an error. */ 2979 if (child->bs->inherits_from != bs) { 2980 continue; 2981 } 2982 2983 child_key_dot = g_strdup_printf("%s.", child->name); 2984 qdict_extract_subqdict(explicit_options, NULL, child_key_dot); 2985 qdict_extract_subqdict(options, &new_child_options, child_key_dot); 2986 g_free(child_key_dot); 2987 2988 bdrv_reopen_queue_child(bs_queue, child->bs, new_child_options, 0, 2989 child->role, options, flags); 2990 } 2991 2992 return bs_queue; 2993 } 2994 2995 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, 2996 BlockDriverState *bs, 2997 QDict *options, int flags) 2998 { 2999 return bdrv_reopen_queue_child(bs_queue, bs, options, flags, 3000 NULL, NULL, 0); 3001 } 3002 3003 /* 3004 * Reopen multiple BlockDriverStates atomically & transactionally. 3005 * 3006 * The queue passed in (bs_queue) must have been built up previous 3007 * via bdrv_reopen_queue(). 3008 * 3009 * Reopens all BDS specified in the queue, with the appropriate 3010 * flags. All devices are prepared for reopen, and failure of any 3011 * device will cause all device changes to be abandoned, and intermediate 3012 * data cleaned up. 3013 * 3014 * If all devices prepare successfully, then the changes are committed 3015 * to all devices. 3016 * 3017 * All affected nodes must be drained between bdrv_reopen_queue() and 3018 * bdrv_reopen_multiple(). 3019 */ 3020 int bdrv_reopen_multiple(AioContext *ctx, BlockReopenQueue *bs_queue, Error **errp) 3021 { 3022 int ret = -1; 3023 BlockReopenQueueEntry *bs_entry, *next; 3024 Error *local_err = NULL; 3025 3026 assert(bs_queue != NULL); 3027 3028 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 3029 assert(bs_entry->state.bs->quiesce_counter > 0); 3030 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { 3031 error_propagate(errp, local_err); 3032 goto cleanup; 3033 } 3034 bs_entry->prepared = true; 3035 } 3036 3037 /* If we reach this point, we have success and just need to apply the 3038 * changes 3039 */ 3040 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 3041 bdrv_reopen_commit(&bs_entry->state); 3042 } 3043 3044 ret = 0; 3045 3046 cleanup: 3047 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { 3048 if (ret) { 3049 if (bs_entry->prepared) { 3050 bdrv_reopen_abort(&bs_entry->state); 3051 } 3052 qobject_unref(bs_entry->state.explicit_options); 3053 qobject_unref(bs_entry->state.options); 3054 } 3055 g_free(bs_entry); 3056 } 3057 g_free(bs_queue); 3058 3059 return ret; 3060 } 3061 3062 3063 /* Reopen a single BlockDriverState with the specified flags. */ 3064 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) 3065 { 3066 int ret = -1; 3067 Error *local_err = NULL; 3068 BlockReopenQueue *queue; 3069 3070 bdrv_subtree_drained_begin(bs); 3071 3072 queue = bdrv_reopen_queue(NULL, bs, NULL, bdrv_flags); 3073 ret = bdrv_reopen_multiple(bdrv_get_aio_context(bs), queue, &local_err); 3074 if (local_err != NULL) { 3075 error_propagate(errp, local_err); 3076 } 3077 3078 bdrv_subtree_drained_end(bs); 3079 3080 return ret; 3081 } 3082 3083 static BlockReopenQueueEntry *find_parent_in_reopen_queue(BlockReopenQueue *q, 3084 BdrvChild *c) 3085 { 3086 BlockReopenQueueEntry *entry; 3087 3088 QSIMPLEQ_FOREACH(entry, q, entry) { 3089 BlockDriverState *bs = entry->state.bs; 3090 BdrvChild *child; 3091 3092 QLIST_FOREACH(child, &bs->children, next) { 3093 if (child == c) { 3094 return entry; 3095 } 3096 } 3097 } 3098 3099 return NULL; 3100 } 3101 3102 static void bdrv_reopen_perm(BlockReopenQueue *q, BlockDriverState *bs, 3103 uint64_t *perm, uint64_t *shared) 3104 { 3105 BdrvChild *c; 3106 BlockReopenQueueEntry *parent; 3107 uint64_t cumulative_perms = 0; 3108 uint64_t cumulative_shared_perms = BLK_PERM_ALL; 3109 3110 QLIST_FOREACH(c, &bs->parents, next_parent) { 3111 parent = find_parent_in_reopen_queue(q, c); 3112 if (!parent) { 3113 cumulative_perms |= c->perm; 3114 cumulative_shared_perms &= c->shared_perm; 3115 } else { 3116 uint64_t nperm, nshared; 3117 3118 bdrv_child_perm(parent->state.bs, bs, c, c->role, q, 3119 parent->state.perm, parent->state.shared_perm, 3120 &nperm, &nshared); 3121 3122 cumulative_perms |= nperm; 3123 cumulative_shared_perms &= nshared; 3124 } 3125 } 3126 *perm = cumulative_perms; 3127 *shared = cumulative_shared_perms; 3128 } 3129 3130 /* 3131 * Prepares a BlockDriverState for reopen. All changes are staged in the 3132 * 'opaque' field of the BDRVReopenState, which is used and allocated by 3133 * the block driver layer .bdrv_reopen_prepare() 3134 * 3135 * bs is the BlockDriverState to reopen 3136 * flags are the new open flags 3137 * queue is the reopen queue 3138 * 3139 * Returns 0 on success, non-zero on error. On error errp will be set 3140 * as well. 3141 * 3142 * On failure, bdrv_reopen_abort() will be called to clean up any data. 3143 * It is the responsibility of the caller to then call the abort() or 3144 * commit() for any other BDS that have been left in a prepare() state 3145 * 3146 */ 3147 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 3148 Error **errp) 3149 { 3150 int ret = -1; 3151 Error *local_err = NULL; 3152 BlockDriver *drv; 3153 QemuOpts *opts; 3154 QDict *orig_reopen_opts; 3155 const char *value; 3156 bool read_only; 3157 3158 assert(reopen_state != NULL); 3159 assert(reopen_state->bs->drv != NULL); 3160 drv = reopen_state->bs->drv; 3161 3162 /* This function and each driver's bdrv_reopen_prepare() remove 3163 * entries from reopen_state->options as they are processed, so 3164 * we need to make a copy of the original QDict. */ 3165 orig_reopen_opts = qdict_clone_shallow(reopen_state->options); 3166 3167 /* Process generic block layer options */ 3168 opts = qemu_opts_create(&bdrv_runtime_opts, NULL, 0, &error_abort); 3169 qemu_opts_absorb_qdict(opts, reopen_state->options, &local_err); 3170 if (local_err) { 3171 error_propagate(errp, local_err); 3172 ret = -EINVAL; 3173 goto error; 3174 } 3175 3176 update_flags_from_options(&reopen_state->flags, opts); 3177 3178 /* node-name and driver must be unchanged. Put them back into the QDict, so 3179 * that they are checked at the end of this function. */ 3180 value = qemu_opt_get(opts, "node-name"); 3181 if (value) { 3182 qdict_put_str(reopen_state->options, "node-name", value); 3183 } 3184 3185 value = qemu_opt_get(opts, "driver"); 3186 if (value) { 3187 qdict_put_str(reopen_state->options, "driver", value); 3188 } 3189 3190 /* If we are to stay read-only, do not allow permission change 3191 * to r/w. Attempting to set to r/w may fail if either BDRV_O_ALLOW_RDWR is 3192 * not set, or if the BDS still has copy_on_read enabled */ 3193 read_only = !(reopen_state->flags & BDRV_O_RDWR); 3194 ret = bdrv_can_set_read_only(reopen_state->bs, read_only, true, &local_err); 3195 if (local_err) { 3196 error_propagate(errp, local_err); 3197 goto error; 3198 } 3199 3200 /* Calculate required permissions after reopening */ 3201 bdrv_reopen_perm(queue, reopen_state->bs, 3202 &reopen_state->perm, &reopen_state->shared_perm); 3203 3204 ret = bdrv_flush(reopen_state->bs); 3205 if (ret) { 3206 error_setg_errno(errp, -ret, "Error flushing drive"); 3207 goto error; 3208 } 3209 3210 if (drv->bdrv_reopen_prepare) { 3211 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); 3212 if (ret) { 3213 if (local_err != NULL) { 3214 error_propagate(errp, local_err); 3215 } else { 3216 error_setg(errp, "failed while preparing to reopen image '%s'", 3217 reopen_state->bs->filename); 3218 } 3219 goto error; 3220 } 3221 } else { 3222 /* It is currently mandatory to have a bdrv_reopen_prepare() 3223 * handler for each supported drv. */ 3224 error_setg(errp, "Block format '%s' used by node '%s' " 3225 "does not support reopening files", drv->format_name, 3226 bdrv_get_device_or_node_name(reopen_state->bs)); 3227 ret = -1; 3228 goto error; 3229 } 3230 3231 /* Options that are not handled are only okay if they are unchanged 3232 * compared to the old state. It is expected that some options are only 3233 * used for the initial open, but not reopen (e.g. filename) */ 3234 if (qdict_size(reopen_state->options)) { 3235 const QDictEntry *entry = qdict_first(reopen_state->options); 3236 3237 do { 3238 QObject *new = entry->value; 3239 QObject *old = qdict_get(reopen_state->bs->options, entry->key); 3240 3241 /* 3242 * TODO: When using -drive to specify blockdev options, all values 3243 * will be strings; however, when using -blockdev, blockdev-add or 3244 * filenames using the json:{} pseudo-protocol, they will be 3245 * correctly typed. 3246 * In contrast, reopening options are (currently) always strings 3247 * (because you can only specify them through qemu-io; all other 3248 * callers do not specify any options). 3249 * Therefore, when using anything other than -drive to create a BDS, 3250 * this cannot detect non-string options as unchanged, because 3251 * qobject_is_equal() always returns false for objects of different 3252 * type. In the future, this should be remedied by correctly typing 3253 * all options. For now, this is not too big of an issue because 3254 * the user can simply omit options which cannot be changed anyway, 3255 * so they will stay unchanged. 3256 */ 3257 if (!qobject_is_equal(new, old)) { 3258 error_setg(errp, "Cannot change the option '%s'", entry->key); 3259 ret = -EINVAL; 3260 goto error; 3261 } 3262 } while ((entry = qdict_next(reopen_state->options, entry))); 3263 } 3264 3265 ret = bdrv_check_perm(reopen_state->bs, queue, reopen_state->perm, 3266 reopen_state->shared_perm, NULL, errp); 3267 if (ret < 0) { 3268 goto error; 3269 } 3270 3271 ret = 0; 3272 3273 /* Restore the original reopen_state->options QDict */ 3274 qobject_unref(reopen_state->options); 3275 reopen_state->options = qobject_ref(orig_reopen_opts); 3276 3277 error: 3278 qemu_opts_del(opts); 3279 qobject_unref(orig_reopen_opts); 3280 return ret; 3281 } 3282 3283 /* 3284 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and 3285 * makes them final by swapping the staging BlockDriverState contents into 3286 * the active BlockDriverState contents. 3287 */ 3288 void bdrv_reopen_commit(BDRVReopenState *reopen_state) 3289 { 3290 BlockDriver *drv; 3291 BlockDriverState *bs; 3292 bool old_can_write, new_can_write; 3293 3294 assert(reopen_state != NULL); 3295 bs = reopen_state->bs; 3296 drv = bs->drv; 3297 assert(drv != NULL); 3298 3299 old_can_write = 3300 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE); 3301 3302 /* If there are any driver level actions to take */ 3303 if (drv->bdrv_reopen_commit) { 3304 drv->bdrv_reopen_commit(reopen_state); 3305 } 3306 3307 /* set BDS specific flags now */ 3308 qobject_unref(bs->explicit_options); 3309 qobject_unref(bs->options); 3310 3311 bs->explicit_options = reopen_state->explicit_options; 3312 bs->options = reopen_state->options; 3313 bs->open_flags = reopen_state->flags; 3314 bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); 3315 3316 bdrv_refresh_limits(bs, NULL); 3317 3318 bdrv_set_perm(reopen_state->bs, reopen_state->perm, 3319 reopen_state->shared_perm); 3320 3321 new_can_write = 3322 !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE); 3323 if (!old_can_write && new_can_write && drv->bdrv_reopen_bitmaps_rw) { 3324 Error *local_err = NULL; 3325 if (drv->bdrv_reopen_bitmaps_rw(bs, &local_err) < 0) { 3326 /* This is not fatal, bitmaps just left read-only, so all following 3327 * writes will fail. User can remove read-only bitmaps to unblock 3328 * writes. 3329 */ 3330 error_reportf_err(local_err, 3331 "%s: Failed to make dirty bitmaps writable: ", 3332 bdrv_get_node_name(bs)); 3333 } 3334 } 3335 } 3336 3337 /* 3338 * Abort the reopen, and delete and free the staged changes in 3339 * reopen_state 3340 */ 3341 void bdrv_reopen_abort(BDRVReopenState *reopen_state) 3342 { 3343 BlockDriver *drv; 3344 3345 assert(reopen_state != NULL); 3346 drv = reopen_state->bs->drv; 3347 assert(drv != NULL); 3348 3349 if (drv->bdrv_reopen_abort) { 3350 drv->bdrv_reopen_abort(reopen_state); 3351 } 3352 3353 bdrv_abort_perm_update(reopen_state->bs); 3354 } 3355 3356 3357 static void bdrv_close(BlockDriverState *bs) 3358 { 3359 BdrvAioNotifier *ban, *ban_next; 3360 BdrvChild *child, *next; 3361 3362 assert(!bs->job); 3363 assert(!bs->refcnt); 3364 3365 bdrv_drained_begin(bs); /* complete I/O */ 3366 bdrv_flush(bs); 3367 bdrv_drain(bs); /* in case flush left pending I/O */ 3368 3369 if (bs->drv) { 3370 if (bs->drv->bdrv_close) { 3371 bs->drv->bdrv_close(bs); 3372 } 3373 bs->drv = NULL; 3374 } 3375 3376 bdrv_set_backing_hd(bs, NULL, &error_abort); 3377 3378 if (bs->file != NULL) { 3379 bdrv_unref_child(bs, bs->file); 3380 bs->file = NULL; 3381 } 3382 3383 QLIST_FOREACH_SAFE(child, &bs->children, next, next) { 3384 /* TODO Remove bdrv_unref() from drivers' close function and use 3385 * bdrv_unref_child() here */ 3386 if (child->bs->inherits_from == bs) { 3387 child->bs->inherits_from = NULL; 3388 } 3389 bdrv_detach_child(child); 3390 } 3391 3392 g_free(bs->opaque); 3393 bs->opaque = NULL; 3394 atomic_set(&bs->copy_on_read, 0); 3395 bs->backing_file[0] = '\0'; 3396 bs->backing_format[0] = '\0'; 3397 bs->total_sectors = 0; 3398 bs->encrypted = false; 3399 bs->sg = false; 3400 qobject_unref(bs->options); 3401 qobject_unref(bs->explicit_options); 3402 bs->options = NULL; 3403 bs->explicit_options = NULL; 3404 qobject_unref(bs->full_open_options); 3405 bs->full_open_options = NULL; 3406 3407 bdrv_release_named_dirty_bitmaps(bs); 3408 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 3409 3410 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { 3411 g_free(ban); 3412 } 3413 QLIST_INIT(&bs->aio_notifiers); 3414 bdrv_drained_end(bs); 3415 } 3416 3417 void bdrv_close_all(void) 3418 { 3419 assert(job_next(NULL) == NULL); 3420 nbd_export_close_all(); 3421 3422 /* Drop references from requests still in flight, such as canceled block 3423 * jobs whose AIO context has not been polled yet */ 3424 bdrv_drain_all(); 3425 3426 blk_remove_all_bs(); 3427 blockdev_close_all_bdrv_states(); 3428 3429 assert(QTAILQ_EMPTY(&all_bdrv_states)); 3430 } 3431 3432 static bool should_update_child(BdrvChild *c, BlockDriverState *to) 3433 { 3434 BdrvChild *to_c; 3435 3436 if (c->role->stay_at_node) { 3437 return false; 3438 } 3439 3440 /* If the child @c belongs to the BDS @to, replacing the current 3441 * c->bs by @to would mean to create a loop. 3442 * 3443 * Such a case occurs when appending a BDS to a backing chain. 3444 * For instance, imagine the following chain: 3445 * 3446 * guest device -> node A -> further backing chain... 3447 * 3448 * Now we create a new BDS B which we want to put on top of this 3449 * chain, so we first attach A as its backing node: 3450 * 3451 * node B 3452 * | 3453 * v 3454 * guest device -> node A -> further backing chain... 3455 * 3456 * Finally we want to replace A by B. When doing that, we want to 3457 * replace all pointers to A by pointers to B -- except for the 3458 * pointer from B because (1) that would create a loop, and (2) 3459 * that pointer should simply stay intact: 3460 * 3461 * guest device -> node B 3462 * | 3463 * v 3464 * node A -> further backing chain... 3465 * 3466 * In general, when replacing a node A (c->bs) by a node B (@to), 3467 * if A is a child of B, that means we cannot replace A by B there 3468 * because that would create a loop. Silently detaching A from B 3469 * is also not really an option. So overall just leaving A in 3470 * place there is the most sensible choice. */ 3471 QLIST_FOREACH(to_c, &to->children, next) { 3472 if (to_c == c) { 3473 return false; 3474 } 3475 } 3476 3477 return true; 3478 } 3479 3480 void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, 3481 Error **errp) 3482 { 3483 BdrvChild *c, *next; 3484 GSList *list = NULL, *p; 3485 uint64_t old_perm, old_shared; 3486 uint64_t perm = 0, shared = BLK_PERM_ALL; 3487 int ret; 3488 3489 assert(!atomic_read(&from->in_flight)); 3490 assert(!atomic_read(&to->in_flight)); 3491 3492 /* Make sure that @from doesn't go away until we have successfully attached 3493 * all of its parents to @to. */ 3494 bdrv_ref(from); 3495 3496 /* Put all parents into @list and calculate their cumulative permissions */ 3497 QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) { 3498 assert(c->bs == from); 3499 if (!should_update_child(c, to)) { 3500 continue; 3501 } 3502 list = g_slist_prepend(list, c); 3503 perm |= c->perm; 3504 shared &= c->shared_perm; 3505 } 3506 3507 /* Check whether the required permissions can be granted on @to, ignoring 3508 * all BdrvChild in @list so that they can't block themselves. */ 3509 ret = bdrv_check_update_perm(to, NULL, perm, shared, list, errp); 3510 if (ret < 0) { 3511 bdrv_abort_perm_update(to); 3512 goto out; 3513 } 3514 3515 /* Now actually perform the change. We performed the permission check for 3516 * all elements of @list at once, so set the permissions all at once at the 3517 * very end. */ 3518 for (p = list; p != NULL; p = p->next) { 3519 c = p->data; 3520 3521 bdrv_ref(to); 3522 bdrv_replace_child_noperm(c, to); 3523 bdrv_unref(from); 3524 } 3525 3526 bdrv_get_cumulative_perm(to, &old_perm, &old_shared); 3527 bdrv_set_perm(to, old_perm | perm, old_shared | shared); 3528 3529 out: 3530 g_slist_free(list); 3531 bdrv_unref(from); 3532 } 3533 3534 /* 3535 * Add new bs contents at the top of an image chain while the chain is 3536 * live, while keeping required fields on the top layer. 3537 * 3538 * This will modify the BlockDriverState fields, and swap contents 3539 * between bs_new and bs_top. Both bs_new and bs_top are modified. 3540 * 3541 * bs_new must not be attached to a BlockBackend. 3542 * 3543 * This function does not create any image files. 3544 * 3545 * bdrv_append() takes ownership of a bs_new reference and unrefs it because 3546 * that's what the callers commonly need. bs_new will be referenced by the old 3547 * parents of bs_top after bdrv_append() returns. If the caller needs to keep a 3548 * reference of its own, it must call bdrv_ref(). 3549 */ 3550 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, 3551 Error **errp) 3552 { 3553 Error *local_err = NULL; 3554 3555 bdrv_set_backing_hd(bs_new, bs_top, &local_err); 3556 if (local_err) { 3557 error_propagate(errp, local_err); 3558 goto out; 3559 } 3560 3561 bdrv_replace_node(bs_top, bs_new, &local_err); 3562 if (local_err) { 3563 error_propagate(errp, local_err); 3564 bdrv_set_backing_hd(bs_new, NULL, &error_abort); 3565 goto out; 3566 } 3567 3568 /* bs_new is now referenced by its new parents, we don't need the 3569 * additional reference any more. */ 3570 out: 3571 bdrv_unref(bs_new); 3572 } 3573 3574 static void bdrv_delete(BlockDriverState *bs) 3575 { 3576 assert(!bs->job); 3577 assert(bdrv_op_blocker_is_empty(bs)); 3578 assert(!bs->refcnt); 3579 3580 bdrv_close(bs); 3581 3582 /* remove from list, if necessary */ 3583 if (bs->node_name[0] != '\0') { 3584 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); 3585 } 3586 QTAILQ_REMOVE(&all_bdrv_states, bs, bs_list); 3587 3588 g_free(bs); 3589 } 3590 3591 /* 3592 * Run consistency checks on an image 3593 * 3594 * Returns 0 if the check could be completed (it doesn't mean that the image is 3595 * free of errors) or -errno when an internal error occurred. The results of the 3596 * check are stored in res. 3597 */ 3598 static int coroutine_fn bdrv_co_check(BlockDriverState *bs, 3599 BdrvCheckResult *res, BdrvCheckMode fix) 3600 { 3601 if (bs->drv == NULL) { 3602 return -ENOMEDIUM; 3603 } 3604 if (bs->drv->bdrv_co_check == NULL) { 3605 return -ENOTSUP; 3606 } 3607 3608 memset(res, 0, sizeof(*res)); 3609 return bs->drv->bdrv_co_check(bs, res, fix); 3610 } 3611 3612 typedef struct CheckCo { 3613 BlockDriverState *bs; 3614 BdrvCheckResult *res; 3615 BdrvCheckMode fix; 3616 int ret; 3617 } CheckCo; 3618 3619 static void bdrv_check_co_entry(void *opaque) 3620 { 3621 CheckCo *cco = opaque; 3622 cco->ret = bdrv_co_check(cco->bs, cco->res, cco->fix); 3623 } 3624 3625 int bdrv_check(BlockDriverState *bs, 3626 BdrvCheckResult *res, BdrvCheckMode fix) 3627 { 3628 Coroutine *co; 3629 CheckCo cco = { 3630 .bs = bs, 3631 .res = res, 3632 .ret = -EINPROGRESS, 3633 .fix = fix, 3634 }; 3635 3636 if (qemu_in_coroutine()) { 3637 /* Fast-path if already in coroutine context */ 3638 bdrv_check_co_entry(&cco); 3639 } else { 3640 co = qemu_coroutine_create(bdrv_check_co_entry, &cco); 3641 qemu_coroutine_enter(co); 3642 BDRV_POLL_WHILE(bs, cco.ret == -EINPROGRESS); 3643 } 3644 3645 return cco.ret; 3646 } 3647 3648 /* 3649 * Return values: 3650 * 0 - success 3651 * -EINVAL - backing format specified, but no file 3652 * -ENOSPC - can't update the backing file because no space is left in the 3653 * image file header 3654 * -ENOTSUP - format driver doesn't support changing the backing file 3655 */ 3656 int bdrv_change_backing_file(BlockDriverState *bs, 3657 const char *backing_file, const char *backing_fmt) 3658 { 3659 BlockDriver *drv = bs->drv; 3660 int ret; 3661 3662 if (!drv) { 3663 return -ENOMEDIUM; 3664 } 3665 3666 /* Backing file format doesn't make sense without a backing file */ 3667 if (backing_fmt && !backing_file) { 3668 return -EINVAL; 3669 } 3670 3671 if (drv->bdrv_change_backing_file != NULL) { 3672 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); 3673 } else { 3674 ret = -ENOTSUP; 3675 } 3676 3677 if (ret == 0) { 3678 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 3679 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 3680 } 3681 return ret; 3682 } 3683 3684 /* 3685 * Finds the image layer in the chain that has 'bs' as its backing file. 3686 * 3687 * active is the current topmost image. 3688 * 3689 * Returns NULL if bs is not found in active's image chain, 3690 * or if active == bs. 3691 * 3692 * Returns the bottommost base image if bs == NULL. 3693 */ 3694 BlockDriverState *bdrv_find_overlay(BlockDriverState *active, 3695 BlockDriverState *bs) 3696 { 3697 while (active && bs != backing_bs(active)) { 3698 active = backing_bs(active); 3699 } 3700 3701 return active; 3702 } 3703 3704 /* Given a BDS, searches for the base layer. */ 3705 BlockDriverState *bdrv_find_base(BlockDriverState *bs) 3706 { 3707 return bdrv_find_overlay(bs, NULL); 3708 } 3709 3710 /* 3711 * Drops images above 'base' up to and including 'top', and sets the image 3712 * above 'top' to have base as its backing file. 3713 * 3714 * Requires that the overlay to 'top' is opened r/w, so that the backing file 3715 * information in 'bs' can be properly updated. 3716 * 3717 * E.g., this will convert the following chain: 3718 * bottom <- base <- intermediate <- top <- active 3719 * 3720 * to 3721 * 3722 * bottom <- base <- active 3723 * 3724 * It is allowed for bottom==base, in which case it converts: 3725 * 3726 * base <- intermediate <- top <- active 3727 * 3728 * to 3729 * 3730 * base <- active 3731 * 3732 * If backing_file_str is non-NULL, it will be used when modifying top's 3733 * overlay image metadata. 3734 * 3735 * Error conditions: 3736 * if active == top, that is considered an error 3737 * 3738 */ 3739 int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, 3740 const char *backing_file_str) 3741 { 3742 BdrvChild *c, *next; 3743 Error *local_err = NULL; 3744 int ret = -EIO; 3745 3746 bdrv_ref(top); 3747 3748 if (!top->drv || !base->drv) { 3749 goto exit; 3750 } 3751 3752 /* Make sure that base is in the backing chain of top */ 3753 if (!bdrv_chain_contains(top, base)) { 3754 goto exit; 3755 } 3756 3757 /* success - we can delete the intermediate states, and link top->base */ 3758 /* TODO Check graph modification op blockers (BLK_PERM_GRAPH_MOD) once 3759 * we've figured out how they should work. */ 3760 backing_file_str = backing_file_str ? backing_file_str : base->filename; 3761 3762 QLIST_FOREACH_SAFE(c, &top->parents, next_parent, next) { 3763 /* Check whether we are allowed to switch c from top to base */ 3764 GSList *ignore_children = g_slist_prepend(NULL, c); 3765 bdrv_check_update_perm(base, NULL, c->perm, c->shared_perm, 3766 ignore_children, &local_err); 3767 g_slist_free(ignore_children); 3768 if (local_err) { 3769 ret = -EPERM; 3770 error_report_err(local_err); 3771 goto exit; 3772 } 3773 3774 /* If so, update the backing file path in the image file */ 3775 if (c->role->update_filename) { 3776 ret = c->role->update_filename(c, base, backing_file_str, 3777 &local_err); 3778 if (ret < 0) { 3779 bdrv_abort_perm_update(base); 3780 error_report_err(local_err); 3781 goto exit; 3782 } 3783 } 3784 3785 /* Do the actual switch in the in-memory graph. 3786 * Completes bdrv_check_update_perm() transaction internally. */ 3787 bdrv_ref(base); 3788 bdrv_replace_child(c, base); 3789 bdrv_unref(top); 3790 } 3791 3792 ret = 0; 3793 exit: 3794 bdrv_unref(top); 3795 return ret; 3796 } 3797 3798 /** 3799 * Length of a allocated file in bytes. Sparse files are counted by actual 3800 * allocated space. Return < 0 if error or unknown. 3801 */ 3802 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) 3803 { 3804 BlockDriver *drv = bs->drv; 3805 if (!drv) { 3806 return -ENOMEDIUM; 3807 } 3808 if (drv->bdrv_get_allocated_file_size) { 3809 return drv->bdrv_get_allocated_file_size(bs); 3810 } 3811 if (bs->file) { 3812 return bdrv_get_allocated_file_size(bs->file->bs); 3813 } 3814 return -ENOTSUP; 3815 } 3816 3817 /* 3818 * bdrv_measure: 3819 * @drv: Format driver 3820 * @opts: Creation options for new image 3821 * @in_bs: Existing image containing data for new image (may be NULL) 3822 * @errp: Error object 3823 * Returns: A #BlockMeasureInfo (free using qapi_free_BlockMeasureInfo()) 3824 * or NULL on error 3825 * 3826 * Calculate file size required to create a new image. 3827 * 3828 * If @in_bs is given then space for allocated clusters and zero clusters 3829 * from that image are included in the calculation. If @opts contains a 3830 * backing file that is shared by @in_bs then backing clusters may be omitted 3831 * from the calculation. 3832 * 3833 * If @in_bs is NULL then the calculation includes no allocated clusters 3834 * unless a preallocation option is given in @opts. 3835 * 3836 * Note that @in_bs may use a different BlockDriver from @drv. 3837 * 3838 * If an error occurs the @errp pointer is set. 3839 */ 3840 BlockMeasureInfo *bdrv_measure(BlockDriver *drv, QemuOpts *opts, 3841 BlockDriverState *in_bs, Error **errp) 3842 { 3843 if (!drv->bdrv_measure) { 3844 error_setg(errp, "Block driver '%s' does not support size measurement", 3845 drv->format_name); 3846 return NULL; 3847 } 3848 3849 return drv->bdrv_measure(opts, in_bs, errp); 3850 } 3851 3852 /** 3853 * Return number of sectors on success, -errno on error. 3854 */ 3855 int64_t bdrv_nb_sectors(BlockDriverState *bs) 3856 { 3857 BlockDriver *drv = bs->drv; 3858 3859 if (!drv) 3860 return -ENOMEDIUM; 3861 3862 if (drv->has_variable_length) { 3863 int ret = refresh_total_sectors(bs, bs->total_sectors); 3864 if (ret < 0) { 3865 return ret; 3866 } 3867 } 3868 return bs->total_sectors; 3869 } 3870 3871 /** 3872 * Return length in bytes on success, -errno on error. 3873 * The length is always a multiple of BDRV_SECTOR_SIZE. 3874 */ 3875 int64_t bdrv_getlength(BlockDriverState *bs) 3876 { 3877 int64_t ret = bdrv_nb_sectors(bs); 3878 3879 ret = ret > INT64_MAX / BDRV_SECTOR_SIZE ? -EFBIG : ret; 3880 return ret < 0 ? ret : ret * BDRV_SECTOR_SIZE; 3881 } 3882 3883 /* return 0 as number of sectors if no device present or error */ 3884 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) 3885 { 3886 int64_t nb_sectors = bdrv_nb_sectors(bs); 3887 3888 *nb_sectors_ptr = nb_sectors < 0 ? 0 : nb_sectors; 3889 } 3890 3891 bool bdrv_is_sg(BlockDriverState *bs) 3892 { 3893 return bs->sg; 3894 } 3895 3896 bool bdrv_is_encrypted(BlockDriverState *bs) 3897 { 3898 if (bs->backing && bs->backing->bs->encrypted) { 3899 return true; 3900 } 3901 return bs->encrypted; 3902 } 3903 3904 const char *bdrv_get_format_name(BlockDriverState *bs) 3905 { 3906 return bs->drv ? bs->drv->format_name : NULL; 3907 } 3908 3909 static int qsort_strcmp(const void *a, const void *b) 3910 { 3911 return strcmp(*(char *const *)a, *(char *const *)b); 3912 } 3913 3914 void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 3915 void *opaque) 3916 { 3917 BlockDriver *drv; 3918 int count = 0; 3919 int i; 3920 const char **formats = NULL; 3921 3922 QLIST_FOREACH(drv, &bdrv_drivers, list) { 3923 if (drv->format_name) { 3924 bool found = false; 3925 int i = count; 3926 while (formats && i && !found) { 3927 found = !strcmp(formats[--i], drv->format_name); 3928 } 3929 3930 if (!found) { 3931 formats = g_renew(const char *, formats, count + 1); 3932 formats[count++] = drv->format_name; 3933 } 3934 } 3935 } 3936 3937 for (i = 0; i < (int)ARRAY_SIZE(block_driver_modules); i++) { 3938 const char *format_name = block_driver_modules[i].format_name; 3939 3940 if (format_name) { 3941 bool found = false; 3942 int j = count; 3943 3944 while (formats && j && !found) { 3945 found = !strcmp(formats[--j], format_name); 3946 } 3947 3948 if (!found) { 3949 formats = g_renew(const char *, formats, count + 1); 3950 formats[count++] = format_name; 3951 } 3952 } 3953 } 3954 3955 qsort(formats, count, sizeof(formats[0]), qsort_strcmp); 3956 3957 for (i = 0; i < count; i++) { 3958 it(opaque, formats[i]); 3959 } 3960 3961 g_free(formats); 3962 } 3963 3964 /* This function is to find a node in the bs graph */ 3965 BlockDriverState *bdrv_find_node(const char *node_name) 3966 { 3967 BlockDriverState *bs; 3968 3969 assert(node_name); 3970 3971 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3972 if (!strcmp(node_name, bs->node_name)) { 3973 return bs; 3974 } 3975 } 3976 return NULL; 3977 } 3978 3979 /* Put this QMP function here so it can access the static graph_bdrv_states. */ 3980 BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp) 3981 { 3982 BlockDeviceInfoList *list, *entry; 3983 BlockDriverState *bs; 3984 3985 list = NULL; 3986 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3987 BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp); 3988 if (!info) { 3989 qapi_free_BlockDeviceInfoList(list); 3990 return NULL; 3991 } 3992 entry = g_malloc0(sizeof(*entry)); 3993 entry->value = info; 3994 entry->next = list; 3995 list = entry; 3996 } 3997 3998 return list; 3999 } 4000 4001 BlockDriverState *bdrv_lookup_bs(const char *device, 4002 const char *node_name, 4003 Error **errp) 4004 { 4005 BlockBackend *blk; 4006 BlockDriverState *bs; 4007 4008 if (device) { 4009 blk = blk_by_name(device); 4010 4011 if (blk) { 4012 bs = blk_bs(blk); 4013 if (!bs) { 4014 error_setg(errp, "Device '%s' has no medium", device); 4015 } 4016 4017 return bs; 4018 } 4019 } 4020 4021 if (node_name) { 4022 bs = bdrv_find_node(node_name); 4023 4024 if (bs) { 4025 return bs; 4026 } 4027 } 4028 4029 error_setg(errp, "Cannot find device=%s nor node_name=%s", 4030 device ? device : "", 4031 node_name ? node_name : ""); 4032 return NULL; 4033 } 4034 4035 /* If 'base' is in the same chain as 'top', return true. Otherwise, 4036 * return false. If either argument is NULL, return false. */ 4037 bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) 4038 { 4039 while (top && top != base) { 4040 top = backing_bs(top); 4041 } 4042 4043 return top != NULL; 4044 } 4045 4046 BlockDriverState *bdrv_next_node(BlockDriverState *bs) 4047 { 4048 if (!bs) { 4049 return QTAILQ_FIRST(&graph_bdrv_states); 4050 } 4051 return QTAILQ_NEXT(bs, node_list); 4052 } 4053 4054 BlockDriverState *bdrv_next_all_states(BlockDriverState *bs) 4055 { 4056 if (!bs) { 4057 return QTAILQ_FIRST(&all_bdrv_states); 4058 } 4059 return QTAILQ_NEXT(bs, bs_list); 4060 } 4061 4062 const char *bdrv_get_node_name(const BlockDriverState *bs) 4063 { 4064 return bs->node_name; 4065 } 4066 4067 const char *bdrv_get_parent_name(const BlockDriverState *bs) 4068 { 4069 BdrvChild *c; 4070 const char *name; 4071 4072 /* If multiple parents have a name, just pick the first one. */ 4073 QLIST_FOREACH(c, &bs->parents, next_parent) { 4074 if (c->role->get_name) { 4075 name = c->role->get_name(c); 4076 if (name && *name) { 4077 return name; 4078 } 4079 } 4080 } 4081 4082 return NULL; 4083 } 4084 4085 /* TODO check what callers really want: bs->node_name or blk_name() */ 4086 const char *bdrv_get_device_name(const BlockDriverState *bs) 4087 { 4088 return bdrv_get_parent_name(bs) ?: ""; 4089 } 4090 4091 /* This can be used to identify nodes that might not have a device 4092 * name associated. Since node and device names live in the same 4093 * namespace, the result is unambiguous. The exception is if both are 4094 * absent, then this returns an empty (non-null) string. */ 4095 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs) 4096 { 4097 return bdrv_get_parent_name(bs) ?: bs->node_name; 4098 } 4099 4100 int bdrv_get_flags(BlockDriverState *bs) 4101 { 4102 return bs->open_flags; 4103 } 4104 4105 int bdrv_has_zero_init_1(BlockDriverState *bs) 4106 { 4107 return 1; 4108 } 4109 4110 int bdrv_has_zero_init(BlockDriverState *bs) 4111 { 4112 if (!bs->drv) { 4113 return 0; 4114 } 4115 4116 /* If BS is a copy on write image, it is initialized to 4117 the contents of the base image, which may not be zeroes. */ 4118 if (bs->backing) { 4119 return 0; 4120 } 4121 if (bs->drv->bdrv_has_zero_init) { 4122 return bs->drv->bdrv_has_zero_init(bs); 4123 } 4124 if (bs->file && bs->drv->is_filter) { 4125 return bdrv_has_zero_init(bs->file->bs); 4126 } 4127 4128 /* safe default */ 4129 return 0; 4130 } 4131 4132 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) 4133 { 4134 BlockDriverInfo bdi; 4135 4136 if (bs->backing) { 4137 return false; 4138 } 4139 4140 if (bdrv_get_info(bs, &bdi) == 0) { 4141 return bdi.unallocated_blocks_are_zero; 4142 } 4143 4144 return false; 4145 } 4146 4147 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) 4148 { 4149 if (!(bs->open_flags & BDRV_O_UNMAP)) { 4150 return false; 4151 } 4152 4153 return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP; 4154 } 4155 4156 const char *bdrv_get_encrypted_filename(BlockDriverState *bs) 4157 { 4158 if (bs->backing && bs->backing->bs->encrypted) 4159 return bs->backing_file; 4160 else if (bs->encrypted) 4161 return bs->filename; 4162 else 4163 return NULL; 4164 } 4165 4166 void bdrv_get_backing_filename(BlockDriverState *bs, 4167 char *filename, int filename_size) 4168 { 4169 pstrcpy(filename, filename_size, bs->backing_file); 4170 } 4171 4172 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 4173 { 4174 BlockDriver *drv = bs->drv; 4175 /* if bs->drv == NULL, bs is closed, so there's nothing to do here */ 4176 if (!drv) { 4177 return -ENOMEDIUM; 4178 } 4179 if (!drv->bdrv_get_info) { 4180 if (bs->file && drv->is_filter) { 4181 return bdrv_get_info(bs->file->bs, bdi); 4182 } 4183 return -ENOTSUP; 4184 } 4185 memset(bdi, 0, sizeof(*bdi)); 4186 return drv->bdrv_get_info(bs, bdi); 4187 } 4188 4189 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) 4190 { 4191 BlockDriver *drv = bs->drv; 4192 if (drv && drv->bdrv_get_specific_info) { 4193 return drv->bdrv_get_specific_info(bs); 4194 } 4195 return NULL; 4196 } 4197 4198 void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event) 4199 { 4200 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { 4201 return; 4202 } 4203 4204 bs->drv->bdrv_debug_event(bs, event); 4205 } 4206 4207 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, 4208 const char *tag) 4209 { 4210 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { 4211 bs = bs->file ? bs->file->bs : NULL; 4212 } 4213 4214 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { 4215 return bs->drv->bdrv_debug_breakpoint(bs, event, tag); 4216 } 4217 4218 return -ENOTSUP; 4219 } 4220 4221 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) 4222 { 4223 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { 4224 bs = bs->file ? bs->file->bs : NULL; 4225 } 4226 4227 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { 4228 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); 4229 } 4230 4231 return -ENOTSUP; 4232 } 4233 4234 int bdrv_debug_resume(BlockDriverState *bs, const char *tag) 4235 { 4236 while (bs && (!bs->drv || !bs->drv->bdrv_debug_resume)) { 4237 bs = bs->file ? bs->file->bs : NULL; 4238 } 4239 4240 if (bs && bs->drv && bs->drv->bdrv_debug_resume) { 4241 return bs->drv->bdrv_debug_resume(bs, tag); 4242 } 4243 4244 return -ENOTSUP; 4245 } 4246 4247 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) 4248 { 4249 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { 4250 bs = bs->file ? bs->file->bs : NULL; 4251 } 4252 4253 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { 4254 return bs->drv->bdrv_debug_is_suspended(bs, tag); 4255 } 4256 4257 return false; 4258 } 4259 4260 /* backing_file can either be relative, or absolute, or a protocol. If it is 4261 * relative, it must be relative to the chain. So, passing in bs->filename 4262 * from a BDS as backing_file should not be done, as that may be relative to 4263 * the CWD rather than the chain. */ 4264 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 4265 const char *backing_file) 4266 { 4267 char *filename_full = NULL; 4268 char *backing_file_full = NULL; 4269 char *filename_tmp = NULL; 4270 int is_protocol = 0; 4271 BlockDriverState *curr_bs = NULL; 4272 BlockDriverState *retval = NULL; 4273 Error *local_error = NULL; 4274 4275 if (!bs || !bs->drv || !backing_file) { 4276 return NULL; 4277 } 4278 4279 filename_full = g_malloc(PATH_MAX); 4280 backing_file_full = g_malloc(PATH_MAX); 4281 filename_tmp = g_malloc(PATH_MAX); 4282 4283 is_protocol = path_has_protocol(backing_file); 4284 4285 for (curr_bs = bs; curr_bs->backing; curr_bs = curr_bs->backing->bs) { 4286 4287 /* If either of the filename paths is actually a protocol, then 4288 * compare unmodified paths; otherwise make paths relative */ 4289 if (is_protocol || path_has_protocol(curr_bs->backing_file)) { 4290 if (strcmp(backing_file, curr_bs->backing_file) == 0) { 4291 retval = curr_bs->backing->bs; 4292 break; 4293 } 4294 /* Also check against the full backing filename for the image */ 4295 bdrv_get_full_backing_filename(curr_bs, backing_file_full, PATH_MAX, 4296 &local_error); 4297 if (local_error == NULL) { 4298 if (strcmp(backing_file, backing_file_full) == 0) { 4299 retval = curr_bs->backing->bs; 4300 break; 4301 } 4302 } else { 4303 error_free(local_error); 4304 local_error = NULL; 4305 } 4306 } else { 4307 /* If not an absolute filename path, make it relative to the current 4308 * image's filename path */ 4309 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 4310 backing_file); 4311 4312 /* We are going to compare absolute pathnames */ 4313 if (!realpath(filename_tmp, filename_full)) { 4314 continue; 4315 } 4316 4317 /* We need to make sure the backing filename we are comparing against 4318 * is relative to the current image filename (or absolute) */ 4319 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 4320 curr_bs->backing_file); 4321 4322 if (!realpath(filename_tmp, backing_file_full)) { 4323 continue; 4324 } 4325 4326 if (strcmp(backing_file_full, filename_full) == 0) { 4327 retval = curr_bs->backing->bs; 4328 break; 4329 } 4330 } 4331 } 4332 4333 g_free(filename_full); 4334 g_free(backing_file_full); 4335 g_free(filename_tmp); 4336 return retval; 4337 } 4338 4339 void bdrv_init(void) 4340 { 4341 module_call_init(MODULE_INIT_BLOCK); 4342 } 4343 4344 void bdrv_init_with_whitelist(void) 4345 { 4346 use_bdrv_whitelist = 1; 4347 bdrv_init(); 4348 } 4349 4350 static void coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, 4351 Error **errp) 4352 { 4353 BdrvChild *child, *parent; 4354 uint64_t perm, shared_perm; 4355 Error *local_err = NULL; 4356 int ret; 4357 4358 if (!bs->drv) { 4359 return; 4360 } 4361 4362 if (!(bs->open_flags & BDRV_O_INACTIVE)) { 4363 return; 4364 } 4365 4366 QLIST_FOREACH(child, &bs->children, next) { 4367 bdrv_co_invalidate_cache(child->bs, &local_err); 4368 if (local_err) { 4369 error_propagate(errp, local_err); 4370 return; 4371 } 4372 } 4373 4374 /* 4375 * Update permissions, they may differ for inactive nodes. 4376 * 4377 * Note that the required permissions of inactive images are always a 4378 * subset of the permissions required after activating the image. This 4379 * allows us to just get the permissions upfront without restricting 4380 * drv->bdrv_invalidate_cache(). 4381 * 4382 * It also means that in error cases, we don't have to try and revert to 4383 * the old permissions (which is an operation that could fail, too). We can 4384 * just keep the extended permissions for the next time that an activation 4385 * of the image is tried. 4386 */ 4387 bs->open_flags &= ~BDRV_O_INACTIVE; 4388 bdrv_get_cumulative_perm(bs, &perm, &shared_perm); 4389 ret = bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &local_err); 4390 if (ret < 0) { 4391 bs->open_flags |= BDRV_O_INACTIVE; 4392 error_propagate(errp, local_err); 4393 return; 4394 } 4395 bdrv_set_perm(bs, perm, shared_perm); 4396 4397 if (bs->drv->bdrv_co_invalidate_cache) { 4398 bs->drv->bdrv_co_invalidate_cache(bs, &local_err); 4399 if (local_err) { 4400 bs->open_flags |= BDRV_O_INACTIVE; 4401 error_propagate(errp, local_err); 4402 return; 4403 } 4404 } 4405 4406 ret = refresh_total_sectors(bs, bs->total_sectors); 4407 if (ret < 0) { 4408 bs->open_flags |= BDRV_O_INACTIVE; 4409 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 4410 return; 4411 } 4412 4413 QLIST_FOREACH(parent, &bs->parents, next_parent) { 4414 if (parent->role->activate) { 4415 parent->role->activate(parent, &local_err); 4416 if (local_err) { 4417 error_propagate(errp, local_err); 4418 return; 4419 } 4420 } 4421 } 4422 } 4423 4424 typedef struct InvalidateCacheCo { 4425 BlockDriverState *bs; 4426 Error **errp; 4427 bool done; 4428 } InvalidateCacheCo; 4429 4430 static void coroutine_fn bdrv_invalidate_cache_co_entry(void *opaque) 4431 { 4432 InvalidateCacheCo *ico = opaque; 4433 bdrv_co_invalidate_cache(ico->bs, ico->errp); 4434 ico->done = true; 4435 } 4436 4437 void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) 4438 { 4439 Coroutine *co; 4440 InvalidateCacheCo ico = { 4441 .bs = bs, 4442 .done = false, 4443 .errp = errp 4444 }; 4445 4446 if (qemu_in_coroutine()) { 4447 /* Fast-path if already in coroutine context */ 4448 bdrv_invalidate_cache_co_entry(&ico); 4449 } else { 4450 co = qemu_coroutine_create(bdrv_invalidate_cache_co_entry, &ico); 4451 qemu_coroutine_enter(co); 4452 BDRV_POLL_WHILE(bs, !ico.done); 4453 } 4454 } 4455 4456 void bdrv_invalidate_cache_all(Error **errp) 4457 { 4458 BlockDriverState *bs; 4459 Error *local_err = NULL; 4460 BdrvNextIterator it; 4461 4462 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4463 AioContext *aio_context = bdrv_get_aio_context(bs); 4464 4465 aio_context_acquire(aio_context); 4466 bdrv_invalidate_cache(bs, &local_err); 4467 aio_context_release(aio_context); 4468 if (local_err) { 4469 error_propagate(errp, local_err); 4470 bdrv_next_cleanup(&it); 4471 return; 4472 } 4473 } 4474 } 4475 4476 static int bdrv_inactivate_recurse(BlockDriverState *bs, 4477 bool setting_flag) 4478 { 4479 BdrvChild *child, *parent; 4480 int ret; 4481 4482 if (!bs->drv) { 4483 return -ENOMEDIUM; 4484 } 4485 4486 if (!setting_flag && bs->drv->bdrv_inactivate) { 4487 ret = bs->drv->bdrv_inactivate(bs); 4488 if (ret < 0) { 4489 return ret; 4490 } 4491 } 4492 4493 if (setting_flag && !(bs->open_flags & BDRV_O_INACTIVE)) { 4494 uint64_t perm, shared_perm; 4495 4496 QLIST_FOREACH(parent, &bs->parents, next_parent) { 4497 if (parent->role->inactivate) { 4498 ret = parent->role->inactivate(parent); 4499 if (ret < 0) { 4500 return ret; 4501 } 4502 } 4503 } 4504 4505 bs->open_flags |= BDRV_O_INACTIVE; 4506 4507 /* Update permissions, they may differ for inactive nodes */ 4508 bdrv_get_cumulative_perm(bs, &perm, &shared_perm); 4509 bdrv_check_perm(bs, NULL, perm, shared_perm, NULL, &error_abort); 4510 bdrv_set_perm(bs, perm, shared_perm); 4511 } 4512 4513 QLIST_FOREACH(child, &bs->children, next) { 4514 ret = bdrv_inactivate_recurse(child->bs, setting_flag); 4515 if (ret < 0) { 4516 return ret; 4517 } 4518 } 4519 4520 /* At this point persistent bitmaps should be already stored by the format 4521 * driver */ 4522 bdrv_release_persistent_dirty_bitmaps(bs); 4523 4524 return 0; 4525 } 4526 4527 int bdrv_inactivate_all(void) 4528 { 4529 BlockDriverState *bs = NULL; 4530 BdrvNextIterator it; 4531 int ret = 0; 4532 int pass; 4533 GSList *aio_ctxs = NULL, *ctx; 4534 4535 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4536 AioContext *aio_context = bdrv_get_aio_context(bs); 4537 4538 if (!g_slist_find(aio_ctxs, aio_context)) { 4539 aio_ctxs = g_slist_prepend(aio_ctxs, aio_context); 4540 aio_context_acquire(aio_context); 4541 } 4542 } 4543 4544 /* We do two passes of inactivation. The first pass calls to drivers' 4545 * .bdrv_inactivate callbacks recursively so all cache is flushed to disk; 4546 * the second pass sets the BDRV_O_INACTIVE flag so that no further write 4547 * is allowed. */ 4548 for (pass = 0; pass < 2; pass++) { 4549 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 4550 ret = bdrv_inactivate_recurse(bs, pass); 4551 if (ret < 0) { 4552 bdrv_next_cleanup(&it); 4553 goto out; 4554 } 4555 } 4556 } 4557 4558 out: 4559 for (ctx = aio_ctxs; ctx != NULL; ctx = ctx->next) { 4560 AioContext *aio_context = ctx->data; 4561 aio_context_release(aio_context); 4562 } 4563 g_slist_free(aio_ctxs); 4564 4565 return ret; 4566 } 4567 4568 /**************************************************************/ 4569 /* removable device support */ 4570 4571 /** 4572 * Return TRUE if the media is present 4573 */ 4574 bool bdrv_is_inserted(BlockDriverState *bs) 4575 { 4576 BlockDriver *drv = bs->drv; 4577 BdrvChild *child; 4578 4579 if (!drv) { 4580 return false; 4581 } 4582 if (drv->bdrv_is_inserted) { 4583 return drv->bdrv_is_inserted(bs); 4584 } 4585 QLIST_FOREACH(child, &bs->children, next) { 4586 if (!bdrv_is_inserted(child->bs)) { 4587 return false; 4588 } 4589 } 4590 return true; 4591 } 4592 4593 /** 4594 * If eject_flag is TRUE, eject the media. Otherwise, close the tray 4595 */ 4596 void bdrv_eject(BlockDriverState *bs, bool eject_flag) 4597 { 4598 BlockDriver *drv = bs->drv; 4599 4600 if (drv && drv->bdrv_eject) { 4601 drv->bdrv_eject(bs, eject_flag); 4602 } 4603 } 4604 4605 /** 4606 * Lock or unlock the media (if it is locked, the user won't be able 4607 * to eject it manually). 4608 */ 4609 void bdrv_lock_medium(BlockDriverState *bs, bool locked) 4610 { 4611 BlockDriver *drv = bs->drv; 4612 4613 trace_bdrv_lock_medium(bs, locked); 4614 4615 if (drv && drv->bdrv_lock_medium) { 4616 drv->bdrv_lock_medium(bs, locked); 4617 } 4618 } 4619 4620 /* Get a reference to bs */ 4621 void bdrv_ref(BlockDriverState *bs) 4622 { 4623 bs->refcnt++; 4624 } 4625 4626 /* Release a previously grabbed reference to bs. 4627 * If after releasing, reference count is zero, the BlockDriverState is 4628 * deleted. */ 4629 void bdrv_unref(BlockDriverState *bs) 4630 { 4631 if (!bs) { 4632 return; 4633 } 4634 assert(bs->refcnt > 0); 4635 if (--bs->refcnt == 0) { 4636 bdrv_delete(bs); 4637 } 4638 } 4639 4640 struct BdrvOpBlocker { 4641 Error *reason; 4642 QLIST_ENTRY(BdrvOpBlocker) list; 4643 }; 4644 4645 bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) 4646 { 4647 BdrvOpBlocker *blocker; 4648 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); 4649 if (!QLIST_EMPTY(&bs->op_blockers[op])) { 4650 blocker = QLIST_FIRST(&bs->op_blockers[op]); 4651 error_propagate(errp, error_copy(blocker->reason)); 4652 error_prepend(errp, "Node '%s' is busy: ", 4653 bdrv_get_device_or_node_name(bs)); 4654 return true; 4655 } 4656 return false; 4657 } 4658 4659 void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason) 4660 { 4661 BdrvOpBlocker *blocker; 4662 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); 4663 4664 blocker = g_new0(BdrvOpBlocker, 1); 4665 blocker->reason = reason; 4666 QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list); 4667 } 4668 4669 void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason) 4670 { 4671 BdrvOpBlocker *blocker, *next; 4672 assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); 4673 QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) { 4674 if (blocker->reason == reason) { 4675 QLIST_REMOVE(blocker, list); 4676 g_free(blocker); 4677 } 4678 } 4679 } 4680 4681 void bdrv_op_block_all(BlockDriverState *bs, Error *reason) 4682 { 4683 int i; 4684 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 4685 bdrv_op_block(bs, i, reason); 4686 } 4687 } 4688 4689 void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason) 4690 { 4691 int i; 4692 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 4693 bdrv_op_unblock(bs, i, reason); 4694 } 4695 } 4696 4697 bool bdrv_op_blocker_is_empty(BlockDriverState *bs) 4698 { 4699 int i; 4700 4701 for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) { 4702 if (!QLIST_EMPTY(&bs->op_blockers[i])) { 4703 return false; 4704 } 4705 } 4706 return true; 4707 } 4708 4709 void bdrv_img_create(const char *filename, const char *fmt, 4710 const char *base_filename, const char *base_fmt, 4711 char *options, uint64_t img_size, int flags, bool quiet, 4712 Error **errp) 4713 { 4714 QemuOptsList *create_opts = NULL; 4715 QemuOpts *opts = NULL; 4716 const char *backing_fmt, *backing_file; 4717 int64_t size; 4718 BlockDriver *drv, *proto_drv; 4719 Error *local_err = NULL; 4720 int ret = 0; 4721 4722 /* Find driver and parse its options */ 4723 drv = bdrv_find_format(fmt); 4724 if (!drv) { 4725 error_setg(errp, "Unknown file format '%s'", fmt); 4726 return; 4727 } 4728 4729 proto_drv = bdrv_find_protocol(filename, true, errp); 4730 if (!proto_drv) { 4731 return; 4732 } 4733 4734 if (!drv->create_opts) { 4735 error_setg(errp, "Format driver '%s' does not support image creation", 4736 drv->format_name); 4737 return; 4738 } 4739 4740 if (!proto_drv->create_opts) { 4741 error_setg(errp, "Protocol driver '%s' does not support image creation", 4742 proto_drv->format_name); 4743 return; 4744 } 4745 4746 create_opts = qemu_opts_append(create_opts, drv->create_opts); 4747 create_opts = qemu_opts_append(create_opts, proto_drv->create_opts); 4748 4749 /* Create parameter list with default values */ 4750 opts = qemu_opts_create(create_opts, NULL, 0, &error_abort); 4751 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, img_size, &error_abort); 4752 4753 /* Parse -o options */ 4754 if (options) { 4755 qemu_opts_do_parse(opts, options, NULL, &local_err); 4756 if (local_err) { 4757 error_report_err(local_err); 4758 local_err = NULL; 4759 error_setg(errp, "Invalid options for file format '%s'", fmt); 4760 goto out; 4761 } 4762 } 4763 4764 if (base_filename) { 4765 qemu_opt_set(opts, BLOCK_OPT_BACKING_FILE, base_filename, &local_err); 4766 if (local_err) { 4767 error_setg(errp, "Backing file not supported for file format '%s'", 4768 fmt); 4769 goto out; 4770 } 4771 } 4772 4773 if (base_fmt) { 4774 qemu_opt_set(opts, BLOCK_OPT_BACKING_FMT, base_fmt, &local_err); 4775 if (local_err) { 4776 error_setg(errp, "Backing file format not supported for file " 4777 "format '%s'", fmt); 4778 goto out; 4779 } 4780 } 4781 4782 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 4783 if (backing_file) { 4784 if (!strcmp(filename, backing_file)) { 4785 error_setg(errp, "Error: Trying to create an image with the " 4786 "same filename as the backing file"); 4787 goto out; 4788 } 4789 } 4790 4791 backing_fmt = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 4792 4793 /* The size for the image must always be specified, unless we have a backing 4794 * file and we have not been forbidden from opening it. */ 4795 size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, img_size); 4796 if (backing_file && !(flags & BDRV_O_NO_BACKING)) { 4797 BlockDriverState *bs; 4798 char *full_backing = g_new0(char, PATH_MAX); 4799 int back_flags; 4800 QDict *backing_options = NULL; 4801 4802 bdrv_get_full_backing_filename_from_filename(filename, backing_file, 4803 full_backing, PATH_MAX, 4804 &local_err); 4805 if (local_err) { 4806 g_free(full_backing); 4807 goto out; 4808 } 4809 4810 /* backing files always opened read-only */ 4811 back_flags = flags; 4812 back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 4813 4814 backing_options = qdict_new(); 4815 if (backing_fmt) { 4816 qdict_put_str(backing_options, "driver", backing_fmt); 4817 } 4818 qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true); 4819 4820 bs = bdrv_open(full_backing, NULL, backing_options, back_flags, 4821 &local_err); 4822 g_free(full_backing); 4823 if (!bs && size != -1) { 4824 /* Couldn't open BS, but we have a size, so it's nonfatal */ 4825 warn_reportf_err(local_err, 4826 "Could not verify backing image. " 4827 "This may become an error in future versions.\n"); 4828 local_err = NULL; 4829 } else if (!bs) { 4830 /* Couldn't open bs, do not have size */ 4831 error_append_hint(&local_err, 4832 "Could not open backing image to determine size.\n"); 4833 goto out; 4834 } else { 4835 if (size == -1) { 4836 /* Opened BS, have no size */ 4837 size = bdrv_getlength(bs); 4838 if (size < 0) { 4839 error_setg_errno(errp, -size, "Could not get size of '%s'", 4840 backing_file); 4841 bdrv_unref(bs); 4842 goto out; 4843 } 4844 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, size, &error_abort); 4845 } 4846 bdrv_unref(bs); 4847 } 4848 } /* (backing_file && !(flags & BDRV_O_NO_BACKING)) */ 4849 4850 if (size == -1) { 4851 error_setg(errp, "Image creation needs a size parameter"); 4852 goto out; 4853 } 4854 4855 if (!quiet) { 4856 printf("Formatting '%s', fmt=%s ", filename, fmt); 4857 qemu_opts_print(opts, " "); 4858 puts(""); 4859 } 4860 4861 ret = bdrv_create(drv, filename, opts, &local_err); 4862 4863 if (ret == -EFBIG) { 4864 /* This is generally a better message than whatever the driver would 4865 * deliver (especially because of the cluster_size_hint), since that 4866 * is most probably not much different from "image too large". */ 4867 const char *cluster_size_hint = ""; 4868 if (qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 0)) { 4869 cluster_size_hint = " (try using a larger cluster size)"; 4870 } 4871 error_setg(errp, "The image size is too large for file format '%s'" 4872 "%s", fmt, cluster_size_hint); 4873 error_free(local_err); 4874 local_err = NULL; 4875 } 4876 4877 out: 4878 qemu_opts_del(opts); 4879 qemu_opts_free(create_opts); 4880 error_propagate(errp, local_err); 4881 } 4882 4883 AioContext *bdrv_get_aio_context(BlockDriverState *bs) 4884 { 4885 return bs ? bs->aio_context : qemu_get_aio_context(); 4886 } 4887 4888 AioWait *bdrv_get_aio_wait(BlockDriverState *bs) 4889 { 4890 return bs ? &bs->wait : NULL; 4891 } 4892 4893 void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co) 4894 { 4895 aio_co_enter(bdrv_get_aio_context(bs), co); 4896 } 4897 4898 static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban) 4899 { 4900 QLIST_REMOVE(ban, list); 4901 g_free(ban); 4902 } 4903 4904 void bdrv_detach_aio_context(BlockDriverState *bs) 4905 { 4906 BdrvAioNotifier *baf, *baf_tmp; 4907 BdrvChild *child; 4908 4909 if (!bs->drv) { 4910 return; 4911 } 4912 4913 assert(!bs->walking_aio_notifiers); 4914 bs->walking_aio_notifiers = true; 4915 QLIST_FOREACH_SAFE(baf, &bs->aio_notifiers, list, baf_tmp) { 4916 if (baf->deleted) { 4917 bdrv_do_remove_aio_context_notifier(baf); 4918 } else { 4919 baf->detach_aio_context(baf->opaque); 4920 } 4921 } 4922 /* Never mind iterating again to check for ->deleted. bdrv_close() will 4923 * remove remaining aio notifiers if we aren't called again. 4924 */ 4925 bs->walking_aio_notifiers = false; 4926 4927 if (bs->drv->bdrv_detach_aio_context) { 4928 bs->drv->bdrv_detach_aio_context(bs); 4929 } 4930 QLIST_FOREACH(child, &bs->children, next) { 4931 bdrv_detach_aio_context(child->bs); 4932 } 4933 4934 bs->aio_context = NULL; 4935 } 4936 4937 void bdrv_attach_aio_context(BlockDriverState *bs, 4938 AioContext *new_context) 4939 { 4940 BdrvAioNotifier *ban, *ban_tmp; 4941 BdrvChild *child; 4942 4943 if (!bs->drv) { 4944 return; 4945 } 4946 4947 bs->aio_context = new_context; 4948 4949 QLIST_FOREACH(child, &bs->children, next) { 4950 bdrv_attach_aio_context(child->bs, new_context); 4951 } 4952 if (bs->drv->bdrv_attach_aio_context) { 4953 bs->drv->bdrv_attach_aio_context(bs, new_context); 4954 } 4955 4956 assert(!bs->walking_aio_notifiers); 4957 bs->walking_aio_notifiers = true; 4958 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_tmp) { 4959 if (ban->deleted) { 4960 bdrv_do_remove_aio_context_notifier(ban); 4961 } else { 4962 ban->attached_aio_context(new_context, ban->opaque); 4963 } 4964 } 4965 bs->walking_aio_notifiers = false; 4966 } 4967 4968 void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) 4969 { 4970 AioContext *ctx = bdrv_get_aio_context(bs); 4971 4972 aio_disable_external(ctx); 4973 bdrv_parent_drained_begin(bs, NULL, false); 4974 bdrv_drain(bs); /* ensure there are no in-flight requests */ 4975 4976 while (aio_poll(ctx, false)) { 4977 /* wait for all bottom halves to execute */ 4978 } 4979 4980 bdrv_detach_aio_context(bs); 4981 4982 /* This function executes in the old AioContext so acquire the new one in 4983 * case it runs in a different thread. 4984 */ 4985 aio_context_acquire(new_context); 4986 bdrv_attach_aio_context(bs, new_context); 4987 bdrv_parent_drained_end(bs, NULL, false); 4988 aio_enable_external(ctx); 4989 aio_context_release(new_context); 4990 } 4991 4992 void bdrv_add_aio_context_notifier(BlockDriverState *bs, 4993 void (*attached_aio_context)(AioContext *new_context, void *opaque), 4994 void (*detach_aio_context)(void *opaque), void *opaque) 4995 { 4996 BdrvAioNotifier *ban = g_new(BdrvAioNotifier, 1); 4997 *ban = (BdrvAioNotifier){ 4998 .attached_aio_context = attached_aio_context, 4999 .detach_aio_context = detach_aio_context, 5000 .opaque = opaque 5001 }; 5002 5003 QLIST_INSERT_HEAD(&bs->aio_notifiers, ban, list); 5004 } 5005 5006 void bdrv_remove_aio_context_notifier(BlockDriverState *bs, 5007 void (*attached_aio_context)(AioContext *, 5008 void *), 5009 void (*detach_aio_context)(void *), 5010 void *opaque) 5011 { 5012 BdrvAioNotifier *ban, *ban_next; 5013 5014 QLIST_FOREACH_SAFE(ban, &bs->aio_notifiers, list, ban_next) { 5015 if (ban->attached_aio_context == attached_aio_context && 5016 ban->detach_aio_context == detach_aio_context && 5017 ban->opaque == opaque && 5018 ban->deleted == false) 5019 { 5020 if (bs->walking_aio_notifiers) { 5021 ban->deleted = true; 5022 } else { 5023 bdrv_do_remove_aio_context_notifier(ban); 5024 } 5025 return; 5026 } 5027 } 5028 5029 abort(); 5030 } 5031 5032 int bdrv_amend_options(BlockDriverState *bs, QemuOpts *opts, 5033 BlockDriverAmendStatusCB *status_cb, void *cb_opaque, 5034 Error **errp) 5035 { 5036 if (!bs->drv) { 5037 error_setg(errp, "Node is ejected"); 5038 return -ENOMEDIUM; 5039 } 5040 if (!bs->drv->bdrv_amend_options) { 5041 error_setg(errp, "Block driver '%s' does not support option amendment", 5042 bs->drv->format_name); 5043 return -ENOTSUP; 5044 } 5045 return bs->drv->bdrv_amend_options(bs, opts, status_cb, cb_opaque, errp); 5046 } 5047 5048 /* This function will be called by the bdrv_recurse_is_first_non_filter method 5049 * of block filter and by bdrv_is_first_non_filter. 5050 * It is used to test if the given bs is the candidate or recurse more in the 5051 * node graph. 5052 */ 5053 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, 5054 BlockDriverState *candidate) 5055 { 5056 /* return false if basic checks fails */ 5057 if (!bs || !bs->drv) { 5058 return false; 5059 } 5060 5061 /* the code reached a non block filter driver -> check if the bs is 5062 * the same as the candidate. It's the recursion termination condition. 5063 */ 5064 if (!bs->drv->is_filter) { 5065 return bs == candidate; 5066 } 5067 /* Down this path the driver is a block filter driver */ 5068 5069 /* If the block filter recursion method is defined use it to recurse down 5070 * the node graph. 5071 */ 5072 if (bs->drv->bdrv_recurse_is_first_non_filter) { 5073 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); 5074 } 5075 5076 /* the driver is a block filter but don't allow to recurse -> return false 5077 */ 5078 return false; 5079 } 5080 5081 /* This function checks if the candidate is the first non filter bs down it's 5082 * bs chain. Since we don't have pointers to parents it explore all bs chains 5083 * from the top. Some filters can choose not to pass down the recursion. 5084 */ 5085 bool bdrv_is_first_non_filter(BlockDriverState *candidate) 5086 { 5087 BlockDriverState *bs; 5088 BdrvNextIterator it; 5089 5090 /* walk down the bs forest recursively */ 5091 for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) { 5092 bool perm; 5093 5094 /* try to recurse in this top level bs */ 5095 perm = bdrv_recurse_is_first_non_filter(bs, candidate); 5096 5097 /* candidate is the first non filter */ 5098 if (perm) { 5099 bdrv_next_cleanup(&it); 5100 return true; 5101 } 5102 } 5103 5104 return false; 5105 } 5106 5107 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs, 5108 const char *node_name, Error **errp) 5109 { 5110 BlockDriverState *to_replace_bs = bdrv_find_node(node_name); 5111 AioContext *aio_context; 5112 5113 if (!to_replace_bs) { 5114 error_setg(errp, "Node name '%s' not found", node_name); 5115 return NULL; 5116 } 5117 5118 aio_context = bdrv_get_aio_context(to_replace_bs); 5119 aio_context_acquire(aio_context); 5120 5121 if (bdrv_op_is_blocked(to_replace_bs, BLOCK_OP_TYPE_REPLACE, errp)) { 5122 to_replace_bs = NULL; 5123 goto out; 5124 } 5125 5126 /* We don't want arbitrary node of the BDS chain to be replaced only the top 5127 * most non filter in order to prevent data corruption. 5128 * Another benefit is that this tests exclude backing files which are 5129 * blocked by the backing blockers. 5130 */ 5131 if (!bdrv_recurse_is_first_non_filter(parent_bs, to_replace_bs)) { 5132 error_setg(errp, "Only top most non filter can be replaced"); 5133 to_replace_bs = NULL; 5134 goto out; 5135 } 5136 5137 out: 5138 aio_context_release(aio_context); 5139 return to_replace_bs; 5140 } 5141 5142 static bool append_open_options(QDict *d, BlockDriverState *bs) 5143 { 5144 const QDictEntry *entry; 5145 QemuOptDesc *desc; 5146 BdrvChild *child; 5147 bool found_any = false; 5148 5149 for (entry = qdict_first(bs->options); entry; 5150 entry = qdict_next(bs->options, entry)) 5151 { 5152 /* Exclude node-name references to children */ 5153 QLIST_FOREACH(child, &bs->children, next) { 5154 if (!strcmp(entry->key, child->name)) { 5155 break; 5156 } 5157 } 5158 if (child) { 5159 continue; 5160 } 5161 5162 /* And exclude all non-driver-specific options */ 5163 for (desc = bdrv_runtime_opts.desc; desc->name; desc++) { 5164 if (!strcmp(qdict_entry_key(entry), desc->name)) { 5165 break; 5166 } 5167 } 5168 if (desc->name) { 5169 continue; 5170 } 5171 5172 qdict_put_obj(d, qdict_entry_key(entry), 5173 qobject_ref(qdict_entry_value(entry))); 5174 found_any = true; 5175 } 5176 5177 return found_any; 5178 } 5179 5180 /* Updates the following BDS fields: 5181 * - exact_filename: A filename which may be used for opening a block device 5182 * which (mostly) equals the given BDS (even without any 5183 * other options; so reading and writing must return the same 5184 * results, but caching etc. may be different) 5185 * - full_open_options: Options which, when given when opening a block device 5186 * (without a filename), result in a BDS (mostly) 5187 * equalling the given one 5188 * - filename: If exact_filename is set, it is copied here. Otherwise, 5189 * full_open_options is converted to a JSON object, prefixed with 5190 * "json:" (for use through the JSON pseudo protocol) and put here. 5191 */ 5192 void bdrv_refresh_filename(BlockDriverState *bs) 5193 { 5194 BlockDriver *drv = bs->drv; 5195 QDict *opts; 5196 5197 if (!drv) { 5198 return; 5199 } 5200 5201 /* This BDS's file name will most probably depend on its file's name, so 5202 * refresh that first */ 5203 if (bs->file) { 5204 bdrv_refresh_filename(bs->file->bs); 5205 } 5206 5207 if (drv->bdrv_refresh_filename) { 5208 /* Obsolete information is of no use here, so drop the old file name 5209 * information before refreshing it */ 5210 bs->exact_filename[0] = '\0'; 5211 if (bs->full_open_options) { 5212 qobject_unref(bs->full_open_options); 5213 bs->full_open_options = NULL; 5214 } 5215 5216 opts = qdict_new(); 5217 append_open_options(opts, bs); 5218 drv->bdrv_refresh_filename(bs, opts); 5219 qobject_unref(opts); 5220 } else if (bs->file) { 5221 /* Try to reconstruct valid information from the underlying file */ 5222 bool has_open_options; 5223 5224 bs->exact_filename[0] = '\0'; 5225 if (bs->full_open_options) { 5226 qobject_unref(bs->full_open_options); 5227 bs->full_open_options = NULL; 5228 } 5229 5230 opts = qdict_new(); 5231 has_open_options = append_open_options(opts, bs); 5232 5233 /* If no specific options have been given for this BDS, the filename of 5234 * the underlying file should suffice for this one as well */ 5235 if (bs->file->bs->exact_filename[0] && !has_open_options) { 5236 strcpy(bs->exact_filename, bs->file->bs->exact_filename); 5237 } 5238 /* Reconstructing the full options QDict is simple for most format block 5239 * drivers, as long as the full options are known for the underlying 5240 * file BDS. The full options QDict of that file BDS should somehow 5241 * contain a representation of the filename, therefore the following 5242 * suffices without querying the (exact_)filename of this BDS. */ 5243 if (bs->file->bs->full_open_options) { 5244 qdict_put_str(opts, "driver", drv->format_name); 5245 qdict_put(opts, "file", 5246 qobject_ref(bs->file->bs->full_open_options)); 5247 5248 bs->full_open_options = opts; 5249 } else { 5250 qobject_unref(opts); 5251 } 5252 } else if (!bs->full_open_options && qdict_size(bs->options)) { 5253 /* There is no underlying file BDS (at least referenced by BDS.file), 5254 * so the full options QDict should be equal to the options given 5255 * specifically for this block device when it was opened (plus the 5256 * driver specification). 5257 * Because those options don't change, there is no need to update 5258 * full_open_options when it's already set. */ 5259 5260 opts = qdict_new(); 5261 append_open_options(opts, bs); 5262 qdict_put_str(opts, "driver", drv->format_name); 5263 5264 if (bs->exact_filename[0]) { 5265 /* This may not work for all block protocol drivers (some may 5266 * require this filename to be parsed), but we have to find some 5267 * default solution here, so just include it. If some block driver 5268 * does not support pure options without any filename at all or 5269 * needs some special format of the options QDict, it needs to 5270 * implement the driver-specific bdrv_refresh_filename() function. 5271 */ 5272 qdict_put_str(opts, "filename", bs->exact_filename); 5273 } 5274 5275 bs->full_open_options = opts; 5276 } 5277 5278 if (bs->exact_filename[0]) { 5279 pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename); 5280 } else if (bs->full_open_options) { 5281 QString *json = qobject_to_json(QOBJECT(bs->full_open_options)); 5282 snprintf(bs->filename, sizeof(bs->filename), "json:%s", 5283 qstring_get_str(json)); 5284 qobject_unref(json); 5285 } 5286 } 5287 5288 /* 5289 * Hot add/remove a BDS's child. So the user can take a child offline when 5290 * it is broken and take a new child online 5291 */ 5292 void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs, 5293 Error **errp) 5294 { 5295 5296 if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) { 5297 error_setg(errp, "The node %s does not support adding a child", 5298 bdrv_get_device_or_node_name(parent_bs)); 5299 return; 5300 } 5301 5302 if (!QLIST_EMPTY(&child_bs->parents)) { 5303 error_setg(errp, "The node %s already has a parent", 5304 child_bs->node_name); 5305 return; 5306 } 5307 5308 parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp); 5309 } 5310 5311 void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp) 5312 { 5313 BdrvChild *tmp; 5314 5315 if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) { 5316 error_setg(errp, "The node %s does not support removing a child", 5317 bdrv_get_device_or_node_name(parent_bs)); 5318 return; 5319 } 5320 5321 QLIST_FOREACH(tmp, &parent_bs->children, next) { 5322 if (tmp == child) { 5323 break; 5324 } 5325 } 5326 5327 if (!tmp) { 5328 error_setg(errp, "The node %s does not have a child named %s", 5329 bdrv_get_device_or_node_name(parent_bs), 5330 bdrv_get_device_or_node_name(child->bs)); 5331 return; 5332 } 5333 5334 parent_bs->drv->bdrv_del_child(parent_bs, child, errp); 5335 } 5336 5337 bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name, 5338 uint32_t granularity, Error **errp) 5339 { 5340 BlockDriver *drv = bs->drv; 5341 5342 if (!drv) { 5343 error_setg_errno(errp, ENOMEDIUM, 5344 "Can't store persistent bitmaps to %s", 5345 bdrv_get_device_or_node_name(bs)); 5346 return false; 5347 } 5348 5349 if (!drv->bdrv_can_store_new_dirty_bitmap) { 5350 error_setg_errno(errp, ENOTSUP, 5351 "Can't store persistent bitmaps to %s", 5352 bdrv_get_device_or_node_name(bs)); 5353 return false; 5354 } 5355 5356 return drv->bdrv_can_store_new_dirty_bitmap(bs, name, granularity, errp); 5357 } 5358