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