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