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 "config-host.h" 25 #include "qemu-common.h" 26 #include "trace.h" 27 #include "monitor/monitor.h" 28 #include "block/block_int.h" 29 #include "block/blockjob.h" 30 #include "qemu/module.h" 31 #include "qapi/qmp/qjson.h" 32 #include "sysemu/sysemu.h" 33 #include "qemu/notify.h" 34 #include "block/coroutine.h" 35 #include "qmp-commands.h" 36 #include "qemu/timer.h" 37 38 #ifdef CONFIG_BSD 39 #include <sys/types.h> 40 #include <sys/stat.h> 41 #include <sys/ioctl.h> 42 #include <sys/queue.h> 43 #ifndef __DragonFly__ 44 #include <sys/disk.h> 45 #endif 46 #endif 47 48 #ifdef _WIN32 49 #include <windows.h> 50 #endif 51 52 struct BdrvDirtyBitmap { 53 HBitmap *bitmap; 54 QLIST_ENTRY(BdrvDirtyBitmap) list; 55 }; 56 57 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ 58 59 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load); 60 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, 61 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 62 BlockDriverCompletionFunc *cb, void *opaque); 63 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, 64 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 65 BlockDriverCompletionFunc *cb, void *opaque); 66 static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, 67 int64_t sector_num, int nb_sectors, 68 QEMUIOVector *iov); 69 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, 70 int64_t sector_num, int nb_sectors, 71 QEMUIOVector *iov); 72 static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, 73 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 74 BdrvRequestFlags flags); 75 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 76 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 77 BdrvRequestFlags flags); 78 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, 79 int64_t sector_num, 80 QEMUIOVector *qiov, 81 int nb_sectors, 82 BdrvRequestFlags flags, 83 BlockDriverCompletionFunc *cb, 84 void *opaque, 85 bool is_write); 86 static void coroutine_fn bdrv_co_do_rw(void *opaque); 87 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, 88 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); 89 90 static QTAILQ_HEAD(, BlockDriverState) bdrv_states = 91 QTAILQ_HEAD_INITIALIZER(bdrv_states); 92 93 static QLIST_HEAD(, BlockDriver) bdrv_drivers = 94 QLIST_HEAD_INITIALIZER(bdrv_drivers); 95 96 /* If non-zero, use only whitelisted block drivers */ 97 static int use_bdrv_whitelist; 98 99 #ifdef _WIN32 100 static int is_windows_drive_prefix(const char *filename) 101 { 102 return (((filename[0] >= 'a' && filename[0] <= 'z') || 103 (filename[0] >= 'A' && filename[0] <= 'Z')) && 104 filename[1] == ':'); 105 } 106 107 int is_windows_drive(const char *filename) 108 { 109 if (is_windows_drive_prefix(filename) && 110 filename[2] == '\0') 111 return 1; 112 if (strstart(filename, "\\\\.\\", NULL) || 113 strstart(filename, "//./", NULL)) 114 return 1; 115 return 0; 116 } 117 #endif 118 119 /* throttling disk I/O limits */ 120 void bdrv_set_io_limits(BlockDriverState *bs, 121 ThrottleConfig *cfg) 122 { 123 int i; 124 125 throttle_config(&bs->throttle_state, cfg); 126 127 for (i = 0; i < 2; i++) { 128 qemu_co_enter_next(&bs->throttled_reqs[i]); 129 } 130 } 131 132 /* this function drain all the throttled IOs */ 133 static bool bdrv_start_throttled_reqs(BlockDriverState *bs) 134 { 135 bool drained = false; 136 bool enabled = bs->io_limits_enabled; 137 int i; 138 139 bs->io_limits_enabled = false; 140 141 for (i = 0; i < 2; i++) { 142 while (qemu_co_enter_next(&bs->throttled_reqs[i])) { 143 drained = true; 144 } 145 } 146 147 bs->io_limits_enabled = enabled; 148 149 return drained; 150 } 151 152 void bdrv_io_limits_disable(BlockDriverState *bs) 153 { 154 bs->io_limits_enabled = false; 155 156 bdrv_start_throttled_reqs(bs); 157 158 throttle_destroy(&bs->throttle_state); 159 } 160 161 static void bdrv_throttle_read_timer_cb(void *opaque) 162 { 163 BlockDriverState *bs = opaque; 164 qemu_co_enter_next(&bs->throttled_reqs[0]); 165 } 166 167 static void bdrv_throttle_write_timer_cb(void *opaque) 168 { 169 BlockDriverState *bs = opaque; 170 qemu_co_enter_next(&bs->throttled_reqs[1]); 171 } 172 173 /* should be called before bdrv_set_io_limits if a limit is set */ 174 void bdrv_io_limits_enable(BlockDriverState *bs) 175 { 176 assert(!bs->io_limits_enabled); 177 throttle_init(&bs->throttle_state, 178 QEMU_CLOCK_VIRTUAL, 179 bdrv_throttle_read_timer_cb, 180 bdrv_throttle_write_timer_cb, 181 bs); 182 bs->io_limits_enabled = true; 183 } 184 185 /* This function makes an IO wait if needed 186 * 187 * @nb_sectors: the number of sectors of the IO 188 * @is_write: is the IO a write 189 */ 190 static void bdrv_io_limits_intercept(BlockDriverState *bs, 191 int nb_sectors, 192 bool is_write) 193 { 194 /* does this io must wait */ 195 bool must_wait = throttle_schedule_timer(&bs->throttle_state, is_write); 196 197 /* if must wait or any request of this type throttled queue the IO */ 198 if (must_wait || 199 !qemu_co_queue_empty(&bs->throttled_reqs[is_write])) { 200 qemu_co_queue_wait(&bs->throttled_reqs[is_write]); 201 } 202 203 /* the IO will be executed, do the accounting */ 204 throttle_account(&bs->throttle_state, 205 is_write, 206 nb_sectors * BDRV_SECTOR_SIZE); 207 208 /* if the next request must wait -> do nothing */ 209 if (throttle_schedule_timer(&bs->throttle_state, is_write)) { 210 return; 211 } 212 213 /* else queue next request for execution */ 214 qemu_co_queue_next(&bs->throttled_reqs[is_write]); 215 } 216 217 /* check if the path starts with "<protocol>:" */ 218 static int path_has_protocol(const char *path) 219 { 220 const char *p; 221 222 #ifdef _WIN32 223 if (is_windows_drive(path) || 224 is_windows_drive_prefix(path)) { 225 return 0; 226 } 227 p = path + strcspn(path, ":/\\"); 228 #else 229 p = path + strcspn(path, ":/"); 230 #endif 231 232 return *p == ':'; 233 } 234 235 int path_is_absolute(const char *path) 236 { 237 #ifdef _WIN32 238 /* specific case for names like: "\\.\d:" */ 239 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { 240 return 1; 241 } 242 return (*path == '/' || *path == '\\'); 243 #else 244 return (*path == '/'); 245 #endif 246 } 247 248 /* if filename is absolute, just copy it to dest. Otherwise, build a 249 path to it by considering it is relative to base_path. URL are 250 supported. */ 251 void path_combine(char *dest, int dest_size, 252 const char *base_path, 253 const char *filename) 254 { 255 const char *p, *p1; 256 int len; 257 258 if (dest_size <= 0) 259 return; 260 if (path_is_absolute(filename)) { 261 pstrcpy(dest, dest_size, filename); 262 } else { 263 p = strchr(base_path, ':'); 264 if (p) 265 p++; 266 else 267 p = base_path; 268 p1 = strrchr(base_path, '/'); 269 #ifdef _WIN32 270 { 271 const char *p2; 272 p2 = strrchr(base_path, '\\'); 273 if (!p1 || p2 > p1) 274 p1 = p2; 275 } 276 #endif 277 if (p1) 278 p1++; 279 else 280 p1 = base_path; 281 if (p1 > p) 282 p = p1; 283 len = p - base_path; 284 if (len > dest_size - 1) 285 len = dest_size - 1; 286 memcpy(dest, base_path, len); 287 dest[len] = '\0'; 288 pstrcat(dest, dest_size, filename); 289 } 290 } 291 292 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz) 293 { 294 if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) { 295 pstrcpy(dest, sz, bs->backing_file); 296 } else { 297 path_combine(dest, sz, bs->filename, bs->backing_file); 298 } 299 } 300 301 void bdrv_register(BlockDriver *bdrv) 302 { 303 /* Block drivers without coroutine functions need emulation */ 304 if (!bdrv->bdrv_co_readv) { 305 bdrv->bdrv_co_readv = bdrv_co_readv_em; 306 bdrv->bdrv_co_writev = bdrv_co_writev_em; 307 308 /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if 309 * the block driver lacks aio we need to emulate that too. 310 */ 311 if (!bdrv->bdrv_aio_readv) { 312 /* add AIO emulation layer */ 313 bdrv->bdrv_aio_readv = bdrv_aio_readv_em; 314 bdrv->bdrv_aio_writev = bdrv_aio_writev_em; 315 } 316 } 317 318 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); 319 } 320 321 /* create a new block device (by default it is empty) */ 322 BlockDriverState *bdrv_new(const char *device_name) 323 { 324 BlockDriverState *bs; 325 326 bs = g_malloc0(sizeof(BlockDriverState)); 327 QLIST_INIT(&bs->dirty_bitmaps); 328 pstrcpy(bs->device_name, sizeof(bs->device_name), device_name); 329 if (device_name[0] != '\0') { 330 QTAILQ_INSERT_TAIL(&bdrv_states, bs, list); 331 } 332 bdrv_iostatus_disable(bs); 333 notifier_list_init(&bs->close_notifiers); 334 notifier_with_return_list_init(&bs->before_write_notifiers); 335 qemu_co_queue_init(&bs->throttled_reqs[0]); 336 qemu_co_queue_init(&bs->throttled_reqs[1]); 337 bs->refcnt = 1; 338 339 return bs; 340 } 341 342 void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify) 343 { 344 notifier_list_add(&bs->close_notifiers, notify); 345 } 346 347 BlockDriver *bdrv_find_format(const char *format_name) 348 { 349 BlockDriver *drv1; 350 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 351 if (!strcmp(drv1->format_name, format_name)) { 352 return drv1; 353 } 354 } 355 return NULL; 356 } 357 358 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) 359 { 360 static const char *whitelist_rw[] = { 361 CONFIG_BDRV_RW_WHITELIST 362 }; 363 static const char *whitelist_ro[] = { 364 CONFIG_BDRV_RO_WHITELIST 365 }; 366 const char **p; 367 368 if (!whitelist_rw[0] && !whitelist_ro[0]) { 369 return 1; /* no whitelist, anything goes */ 370 } 371 372 for (p = whitelist_rw; *p; p++) { 373 if (!strcmp(drv->format_name, *p)) { 374 return 1; 375 } 376 } 377 if (read_only) { 378 for (p = whitelist_ro; *p; p++) { 379 if (!strcmp(drv->format_name, *p)) { 380 return 1; 381 } 382 } 383 } 384 return 0; 385 } 386 387 BlockDriver *bdrv_find_whitelisted_format(const char *format_name, 388 bool read_only) 389 { 390 BlockDriver *drv = bdrv_find_format(format_name); 391 return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL; 392 } 393 394 typedef struct CreateCo { 395 BlockDriver *drv; 396 char *filename; 397 QEMUOptionParameter *options; 398 int ret; 399 Error *err; 400 } CreateCo; 401 402 static void coroutine_fn bdrv_create_co_entry(void *opaque) 403 { 404 Error *local_err = NULL; 405 int ret; 406 407 CreateCo *cco = opaque; 408 assert(cco->drv); 409 410 ret = cco->drv->bdrv_create(cco->filename, cco->options, &local_err); 411 if (error_is_set(&local_err)) { 412 error_propagate(&cco->err, local_err); 413 } 414 cco->ret = ret; 415 } 416 417 int bdrv_create(BlockDriver *drv, const char* filename, 418 QEMUOptionParameter *options, Error **errp) 419 { 420 int ret; 421 422 Coroutine *co; 423 CreateCo cco = { 424 .drv = drv, 425 .filename = g_strdup(filename), 426 .options = options, 427 .ret = NOT_DONE, 428 .err = NULL, 429 }; 430 431 if (!drv->bdrv_create) { 432 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); 433 ret = -ENOTSUP; 434 goto out; 435 } 436 437 if (qemu_in_coroutine()) { 438 /* Fast-path if already in coroutine context */ 439 bdrv_create_co_entry(&cco); 440 } else { 441 co = qemu_coroutine_create(bdrv_create_co_entry); 442 qemu_coroutine_enter(co, &cco); 443 while (cco.ret == NOT_DONE) { 444 qemu_aio_wait(); 445 } 446 } 447 448 ret = cco.ret; 449 if (ret < 0) { 450 if (error_is_set(&cco.err)) { 451 error_propagate(errp, cco.err); 452 } else { 453 error_setg_errno(errp, -ret, "Could not create image"); 454 } 455 } 456 457 out: 458 g_free(cco.filename); 459 return ret; 460 } 461 462 int bdrv_create_file(const char* filename, QEMUOptionParameter *options, 463 Error **errp) 464 { 465 BlockDriver *drv; 466 Error *local_err = NULL; 467 int ret; 468 469 drv = bdrv_find_protocol(filename, true); 470 if (drv == NULL) { 471 error_setg(errp, "Could not find protocol for file '%s'", filename); 472 return -ENOENT; 473 } 474 475 ret = bdrv_create(drv, filename, options, &local_err); 476 if (error_is_set(&local_err)) { 477 error_propagate(errp, local_err); 478 } 479 return ret; 480 } 481 482 /* 483 * Create a uniquely-named empty temporary file. 484 * Return 0 upon success, otherwise a negative errno value. 485 */ 486 int get_tmp_filename(char *filename, int size) 487 { 488 #ifdef _WIN32 489 char temp_dir[MAX_PATH]; 490 /* GetTempFileName requires that its output buffer (4th param) 491 have length MAX_PATH or greater. */ 492 assert(size >= MAX_PATH); 493 return (GetTempPath(MAX_PATH, temp_dir) 494 && GetTempFileName(temp_dir, "qem", 0, filename) 495 ? 0 : -GetLastError()); 496 #else 497 int fd; 498 const char *tmpdir; 499 tmpdir = getenv("TMPDIR"); 500 if (!tmpdir) 501 tmpdir = "/tmp"; 502 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { 503 return -EOVERFLOW; 504 } 505 fd = mkstemp(filename); 506 if (fd < 0) { 507 return -errno; 508 } 509 if (close(fd) != 0) { 510 unlink(filename); 511 return -errno; 512 } 513 return 0; 514 #endif 515 } 516 517 /* 518 * Detect host devices. By convention, /dev/cdrom[N] is always 519 * recognized as a host CDROM. 520 */ 521 static BlockDriver *find_hdev_driver(const char *filename) 522 { 523 int score_max = 0, score; 524 BlockDriver *drv = NULL, *d; 525 526 QLIST_FOREACH(d, &bdrv_drivers, list) { 527 if (d->bdrv_probe_device) { 528 score = d->bdrv_probe_device(filename); 529 if (score > score_max) { 530 score_max = score; 531 drv = d; 532 } 533 } 534 } 535 536 return drv; 537 } 538 539 BlockDriver *bdrv_find_protocol(const char *filename, 540 bool allow_protocol_prefix) 541 { 542 BlockDriver *drv1; 543 char protocol[128]; 544 int len; 545 const char *p; 546 547 /* TODO Drivers without bdrv_file_open must be specified explicitly */ 548 549 /* 550 * XXX(hch): we really should not let host device detection 551 * override an explicit protocol specification, but moving this 552 * later breaks access to device names with colons in them. 553 * Thanks to the brain-dead persistent naming schemes on udev- 554 * based Linux systems those actually are quite common. 555 */ 556 drv1 = find_hdev_driver(filename); 557 if (drv1) { 558 return drv1; 559 } 560 561 if (!path_has_protocol(filename) || !allow_protocol_prefix) { 562 return bdrv_find_format("file"); 563 } 564 565 p = strchr(filename, ':'); 566 assert(p != NULL); 567 len = p - filename; 568 if (len > sizeof(protocol) - 1) 569 len = sizeof(protocol) - 1; 570 memcpy(protocol, filename, len); 571 protocol[len] = '\0'; 572 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 573 if (drv1->protocol_name && 574 !strcmp(drv1->protocol_name, protocol)) { 575 return drv1; 576 } 577 } 578 return NULL; 579 } 580 581 static int find_image_format(BlockDriverState *bs, const char *filename, 582 BlockDriver **pdrv, Error **errp) 583 { 584 int score, score_max; 585 BlockDriver *drv1, *drv; 586 uint8_t buf[2048]; 587 int ret = 0; 588 589 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ 590 if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) { 591 drv = bdrv_find_format("raw"); 592 if (!drv) { 593 error_setg(errp, "Could not find raw image format"); 594 ret = -ENOENT; 595 } 596 *pdrv = drv; 597 return ret; 598 } 599 600 ret = bdrv_pread(bs, 0, buf, sizeof(buf)); 601 if (ret < 0) { 602 error_setg_errno(errp, -ret, "Could not read image for determining its " 603 "format"); 604 *pdrv = NULL; 605 return ret; 606 } 607 608 score_max = 0; 609 drv = NULL; 610 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 611 if (drv1->bdrv_probe) { 612 score = drv1->bdrv_probe(buf, ret, filename); 613 if (score > score_max) { 614 score_max = score; 615 drv = drv1; 616 } 617 } 618 } 619 if (!drv) { 620 error_setg(errp, "Could not determine image format: No compatible " 621 "driver found"); 622 ret = -ENOENT; 623 } 624 *pdrv = drv; 625 return ret; 626 } 627 628 /** 629 * Set the current 'total_sectors' value 630 */ 631 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint) 632 { 633 BlockDriver *drv = bs->drv; 634 635 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ 636 if (bs->sg) 637 return 0; 638 639 /* query actual device if possible, otherwise just trust the hint */ 640 if (drv->bdrv_getlength) { 641 int64_t length = drv->bdrv_getlength(bs); 642 if (length < 0) { 643 return length; 644 } 645 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); 646 } 647 648 bs->total_sectors = hint; 649 return 0; 650 } 651 652 /** 653 * Set open flags for a given discard mode 654 * 655 * Return 0 on success, -1 if the discard mode was invalid. 656 */ 657 int bdrv_parse_discard_flags(const char *mode, int *flags) 658 { 659 *flags &= ~BDRV_O_UNMAP; 660 661 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { 662 /* do nothing */ 663 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { 664 *flags |= BDRV_O_UNMAP; 665 } else { 666 return -1; 667 } 668 669 return 0; 670 } 671 672 /** 673 * Set open flags for a given cache mode 674 * 675 * Return 0 on success, -1 if the cache mode was invalid. 676 */ 677 int bdrv_parse_cache_flags(const char *mode, int *flags) 678 { 679 *flags &= ~BDRV_O_CACHE_MASK; 680 681 if (!strcmp(mode, "off") || !strcmp(mode, "none")) { 682 *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 683 } else if (!strcmp(mode, "directsync")) { 684 *flags |= BDRV_O_NOCACHE; 685 } else if (!strcmp(mode, "writeback")) { 686 *flags |= BDRV_O_CACHE_WB; 687 } else if (!strcmp(mode, "unsafe")) { 688 *flags |= BDRV_O_CACHE_WB; 689 *flags |= BDRV_O_NO_FLUSH; 690 } else if (!strcmp(mode, "writethrough")) { 691 /* this is the default */ 692 } else { 693 return -1; 694 } 695 696 return 0; 697 } 698 699 /** 700 * The copy-on-read flag is actually a reference count so multiple users may 701 * use the feature without worrying about clobbering its previous state. 702 * Copy-on-read stays enabled until all users have called to disable it. 703 */ 704 void bdrv_enable_copy_on_read(BlockDriverState *bs) 705 { 706 bs->copy_on_read++; 707 } 708 709 void bdrv_disable_copy_on_read(BlockDriverState *bs) 710 { 711 assert(bs->copy_on_read > 0); 712 bs->copy_on_read--; 713 } 714 715 static int bdrv_open_flags(BlockDriverState *bs, int flags) 716 { 717 int open_flags = flags | BDRV_O_CACHE_WB; 718 719 /* 720 * Clear flags that are internal to the block layer before opening the 721 * image. 722 */ 723 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 724 725 /* 726 * Snapshots should be writable. 727 */ 728 if (bs->is_temporary) { 729 open_flags |= BDRV_O_RDWR; 730 } 731 732 return open_flags; 733 } 734 735 /* 736 * Common part for opening disk images and files 737 * 738 * Removes all processed options from *options. 739 */ 740 static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file, 741 QDict *options, int flags, BlockDriver *drv, Error **errp) 742 { 743 int ret, open_flags; 744 const char *filename; 745 Error *local_err = NULL; 746 747 assert(drv != NULL); 748 assert(bs->file == NULL); 749 assert(options != NULL && bs->options != options); 750 751 if (file != NULL) { 752 filename = file->filename; 753 } else { 754 filename = qdict_get_try_str(options, "filename"); 755 } 756 757 trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name); 758 759 /* bdrv_open() with directly using a protocol as drv. This layer is already 760 * opened, so assign it to bs (while file becomes a closed BlockDriverState) 761 * and return immediately. */ 762 if (file != NULL && drv->bdrv_file_open) { 763 bdrv_swap(file, bs); 764 return 0; 765 } 766 767 bs->open_flags = flags; 768 bs->buffer_alignment = 512; 769 bs->zero_beyond_eof = true; 770 open_flags = bdrv_open_flags(bs, flags); 771 bs->read_only = !(open_flags & BDRV_O_RDWR); 772 773 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { 774 error_setg(errp, 775 !bs->read_only && bdrv_is_whitelisted(drv, true) 776 ? "Driver '%s' can only be used for read-only devices" 777 : "Driver '%s' is not whitelisted", 778 drv->format_name); 779 return -ENOTSUP; 780 } 781 782 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */ 783 if (flags & BDRV_O_COPY_ON_READ) { 784 if (!bs->read_only) { 785 bdrv_enable_copy_on_read(bs); 786 } else { 787 error_setg(errp, "Can't use copy-on-read on read-only device"); 788 return -EINVAL; 789 } 790 } 791 792 if (filename != NULL) { 793 pstrcpy(bs->filename, sizeof(bs->filename), filename); 794 } else { 795 bs->filename[0] = '\0'; 796 } 797 798 bs->drv = drv; 799 bs->opaque = g_malloc0(drv->instance_size); 800 801 bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB); 802 803 /* Open the image, either directly or using a protocol */ 804 if (drv->bdrv_file_open) { 805 assert(file == NULL); 806 assert(!drv->bdrv_needs_filename || filename != NULL); 807 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); 808 } else { 809 if (file == NULL) { 810 error_setg(errp, "Can't use '%s' as a block driver for the " 811 "protocol level", drv->format_name); 812 ret = -EINVAL; 813 goto free_and_fail; 814 } 815 bs->file = file; 816 ret = drv->bdrv_open(bs, options, open_flags, &local_err); 817 } 818 819 if (ret < 0) { 820 if (error_is_set(&local_err)) { 821 error_propagate(errp, local_err); 822 } else if (bs->filename[0]) { 823 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); 824 } else { 825 error_setg_errno(errp, -ret, "Could not open image"); 826 } 827 goto free_and_fail; 828 } 829 830 ret = refresh_total_sectors(bs, bs->total_sectors); 831 if (ret < 0) { 832 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 833 goto free_and_fail; 834 } 835 836 #ifndef _WIN32 837 if (bs->is_temporary) { 838 assert(bs->filename[0] != '\0'); 839 unlink(bs->filename); 840 } 841 #endif 842 return 0; 843 844 free_and_fail: 845 bs->file = NULL; 846 g_free(bs->opaque); 847 bs->opaque = NULL; 848 bs->drv = NULL; 849 return ret; 850 } 851 852 /* 853 * Opens a file using a protocol (file, host_device, nbd, ...) 854 * 855 * options is a QDict of options to pass to the block drivers, or NULL for an 856 * empty set of options. The reference to the QDict belongs to the block layer 857 * after the call (even on failure), so if the caller intends to reuse the 858 * dictionary, it needs to use QINCREF() before calling bdrv_file_open. 859 */ 860 int bdrv_file_open(BlockDriverState **pbs, const char *filename, 861 QDict *options, int flags, Error **errp) 862 { 863 BlockDriverState *bs; 864 BlockDriver *drv; 865 const char *drvname; 866 bool allow_protocol_prefix = false; 867 Error *local_err = NULL; 868 int ret; 869 870 /* NULL means an empty set of options */ 871 if (options == NULL) { 872 options = qdict_new(); 873 } 874 875 bs = bdrv_new(""); 876 bs->options = options; 877 options = qdict_clone_shallow(options); 878 879 /* Fetch the file name from the options QDict if necessary */ 880 if (!filename) { 881 filename = qdict_get_try_str(options, "filename"); 882 } else if (filename && !qdict_haskey(options, "filename")) { 883 qdict_put(options, "filename", qstring_from_str(filename)); 884 allow_protocol_prefix = true; 885 } else { 886 error_setg(errp, "Can't specify 'file' and 'filename' options at the " 887 "same time"); 888 ret = -EINVAL; 889 goto fail; 890 } 891 892 /* Find the right block driver */ 893 drvname = qdict_get_try_str(options, "driver"); 894 if (drvname) { 895 drv = bdrv_find_format(drvname); 896 if (!drv) { 897 error_setg(errp, "Unknown driver '%s'", drvname); 898 } 899 qdict_del(options, "driver"); 900 } else if (filename) { 901 drv = bdrv_find_protocol(filename, allow_protocol_prefix); 902 if (!drv) { 903 error_setg(errp, "Unknown protocol"); 904 } 905 } else { 906 error_setg(errp, "Must specify either driver or file"); 907 drv = NULL; 908 } 909 910 if (!drv) { 911 /* errp has been set already */ 912 ret = -ENOENT; 913 goto fail; 914 } 915 916 /* Parse the filename and open it */ 917 if (drv->bdrv_parse_filename && filename) { 918 drv->bdrv_parse_filename(filename, options, &local_err); 919 if (error_is_set(&local_err)) { 920 error_propagate(errp, local_err); 921 ret = -EINVAL; 922 goto fail; 923 } 924 qdict_del(options, "filename"); 925 } else if (drv->bdrv_needs_filename && !filename) { 926 error_setg(errp, "The '%s' block driver requires a file name", 927 drv->format_name); 928 ret = -EINVAL; 929 goto fail; 930 } 931 932 ret = bdrv_open_common(bs, NULL, options, flags, drv, &local_err); 933 if (ret < 0) { 934 error_propagate(errp, local_err); 935 goto fail; 936 } 937 938 /* Check if any unknown options were used */ 939 if (qdict_size(options) != 0) { 940 const QDictEntry *entry = qdict_first(options); 941 error_setg(errp, "Block protocol '%s' doesn't support the option '%s'", 942 drv->format_name, entry->key); 943 ret = -EINVAL; 944 goto fail; 945 } 946 QDECREF(options); 947 948 bs->growable = 1; 949 *pbs = bs; 950 return 0; 951 952 fail: 953 QDECREF(options); 954 if (!bs->drv) { 955 QDECREF(bs->options); 956 } 957 bdrv_unref(bs); 958 return ret; 959 } 960 961 /* 962 * Opens the backing file for a BlockDriverState if not yet open 963 * 964 * options is a QDict of options to pass to the block drivers, or NULL for an 965 * empty set of options. The reference to the QDict is transferred to this 966 * function (even on failure), so if the caller intends to reuse the dictionary, 967 * it needs to use QINCREF() before calling bdrv_file_open. 968 */ 969 int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) 970 { 971 char backing_filename[PATH_MAX]; 972 int back_flags, ret; 973 BlockDriver *back_drv = NULL; 974 Error *local_err = NULL; 975 976 if (bs->backing_hd != NULL) { 977 QDECREF(options); 978 return 0; 979 } 980 981 /* NULL means an empty set of options */ 982 if (options == NULL) { 983 options = qdict_new(); 984 } 985 986 bs->open_flags &= ~BDRV_O_NO_BACKING; 987 if (qdict_haskey(options, "file.filename")) { 988 backing_filename[0] = '\0'; 989 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { 990 QDECREF(options); 991 return 0; 992 } else { 993 bdrv_get_full_backing_filename(bs, backing_filename, 994 sizeof(backing_filename)); 995 } 996 997 bs->backing_hd = bdrv_new(""); 998 999 if (bs->backing_format[0] != '\0') { 1000 back_drv = bdrv_find_format(bs->backing_format); 1001 } 1002 1003 /* backing files always opened read-only */ 1004 back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | 1005 BDRV_O_COPY_ON_READ); 1006 1007 ret = bdrv_open(bs->backing_hd, 1008 *backing_filename ? backing_filename : NULL, options, 1009 back_flags, back_drv, &local_err); 1010 if (ret < 0) { 1011 bdrv_unref(bs->backing_hd); 1012 bs->backing_hd = NULL; 1013 bs->open_flags |= BDRV_O_NO_BACKING; 1014 error_setg(errp, "Could not open backing file: %s", 1015 error_get_pretty(local_err)); 1016 error_free(local_err); 1017 return ret; 1018 } 1019 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1020 bs->backing_hd->file->filename); 1021 return 0; 1022 } 1023 1024 /* 1025 * Opens a disk image (raw, qcow2, vmdk, ...) 1026 * 1027 * options is a QDict of options to pass to the block drivers, or NULL for an 1028 * empty set of options. The reference to the QDict belongs to the block layer 1029 * after the call (even on failure), so if the caller intends to reuse the 1030 * dictionary, it needs to use QINCREF() before calling bdrv_open. 1031 */ 1032 int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options, 1033 int flags, BlockDriver *drv, Error **errp) 1034 { 1035 int ret; 1036 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ 1037 char tmp_filename[PATH_MAX + 1]; 1038 BlockDriverState *file = NULL; 1039 QDict *file_options = NULL; 1040 const char *drvname; 1041 Error *local_err = NULL; 1042 1043 /* NULL means an empty set of options */ 1044 if (options == NULL) { 1045 options = qdict_new(); 1046 } 1047 1048 bs->options = options; 1049 options = qdict_clone_shallow(options); 1050 1051 /* For snapshot=on, create a temporary qcow2 overlay */ 1052 if (flags & BDRV_O_SNAPSHOT) { 1053 BlockDriverState *bs1; 1054 int64_t total_size; 1055 BlockDriver *bdrv_qcow2; 1056 QEMUOptionParameter *create_options; 1057 QDict *snapshot_options; 1058 1059 /* if snapshot, we create a temporary backing file and open it 1060 instead of opening 'filename' directly */ 1061 1062 /* Get the required size from the image */ 1063 bs1 = bdrv_new(""); 1064 QINCREF(options); 1065 ret = bdrv_open(bs1, filename, options, BDRV_O_NO_BACKING, 1066 drv, &local_err); 1067 if (ret < 0) { 1068 bdrv_unref(bs1); 1069 goto fail; 1070 } 1071 total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK; 1072 1073 bdrv_unref(bs1); 1074 1075 /* Create the temporary image */ 1076 ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename)); 1077 if (ret < 0) { 1078 error_setg_errno(errp, -ret, "Could not get temporary filename"); 1079 goto fail; 1080 } 1081 1082 bdrv_qcow2 = bdrv_find_format("qcow2"); 1083 create_options = parse_option_parameters("", bdrv_qcow2->create_options, 1084 NULL); 1085 1086 set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size); 1087 1088 ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err); 1089 free_option_parameters(create_options); 1090 if (ret < 0) { 1091 error_setg_errno(errp, -ret, "Could not create temporary overlay " 1092 "'%s': %s", tmp_filename, 1093 error_get_pretty(local_err)); 1094 error_free(local_err); 1095 local_err = NULL; 1096 goto fail; 1097 } 1098 1099 /* Prepare a new options QDict for the temporary file, where user 1100 * options refer to the backing file */ 1101 if (filename) { 1102 qdict_put(options, "file.filename", qstring_from_str(filename)); 1103 } 1104 if (drv) { 1105 qdict_put(options, "driver", qstring_from_str(drv->format_name)); 1106 } 1107 1108 snapshot_options = qdict_new(); 1109 qdict_put(snapshot_options, "backing", options); 1110 qdict_flatten(snapshot_options); 1111 1112 bs->options = snapshot_options; 1113 options = qdict_clone_shallow(bs->options); 1114 1115 filename = tmp_filename; 1116 drv = bdrv_qcow2; 1117 bs->is_temporary = 1; 1118 } 1119 1120 /* Open image file without format layer */ 1121 if (flags & BDRV_O_RDWR) { 1122 flags |= BDRV_O_ALLOW_RDWR; 1123 } 1124 1125 qdict_extract_subqdict(options, &file_options, "file."); 1126 1127 ret = bdrv_file_open(&file, filename, file_options, 1128 bdrv_open_flags(bs, flags | BDRV_O_UNMAP), &local_err); 1129 if (ret < 0) { 1130 goto fail; 1131 } 1132 1133 /* Find the right image format driver */ 1134 drvname = qdict_get_try_str(options, "driver"); 1135 if (drvname) { 1136 drv = bdrv_find_format(drvname); 1137 qdict_del(options, "driver"); 1138 if (!drv) { 1139 error_setg(errp, "Invalid driver: '%s'", drvname); 1140 ret = -EINVAL; 1141 goto unlink_and_fail; 1142 } 1143 } 1144 1145 if (!drv) { 1146 ret = find_image_format(file, filename, &drv, &local_err); 1147 } 1148 1149 if (!drv) { 1150 goto unlink_and_fail; 1151 } 1152 1153 /* Open the image */ 1154 ret = bdrv_open_common(bs, file, options, flags, drv, &local_err); 1155 if (ret < 0) { 1156 goto unlink_and_fail; 1157 } 1158 1159 if (bs->file != file) { 1160 bdrv_unref(file); 1161 file = NULL; 1162 } 1163 1164 /* If there is a backing file, use it */ 1165 if ((flags & BDRV_O_NO_BACKING) == 0) { 1166 QDict *backing_options; 1167 1168 qdict_extract_subqdict(options, &backing_options, "backing."); 1169 ret = bdrv_open_backing_file(bs, backing_options, &local_err); 1170 if (ret < 0) { 1171 goto close_and_fail; 1172 } 1173 } 1174 1175 /* Check if any unknown options were used */ 1176 if (qdict_size(options) != 0) { 1177 const QDictEntry *entry = qdict_first(options); 1178 error_setg(errp, "Block format '%s' used by device '%s' doesn't " 1179 "support the option '%s'", drv->format_name, bs->device_name, 1180 entry->key); 1181 1182 ret = -EINVAL; 1183 goto close_and_fail; 1184 } 1185 QDECREF(options); 1186 1187 if (!bdrv_key_required(bs)) { 1188 bdrv_dev_change_media_cb(bs, true); 1189 } 1190 1191 return 0; 1192 1193 unlink_and_fail: 1194 if (file != NULL) { 1195 bdrv_unref(file); 1196 } 1197 if (bs->is_temporary) { 1198 unlink(filename); 1199 } 1200 fail: 1201 QDECREF(bs->options); 1202 QDECREF(options); 1203 bs->options = NULL; 1204 if (error_is_set(&local_err)) { 1205 error_propagate(errp, local_err); 1206 } 1207 return ret; 1208 1209 close_and_fail: 1210 bdrv_close(bs); 1211 QDECREF(options); 1212 if (error_is_set(&local_err)) { 1213 error_propagate(errp, local_err); 1214 } 1215 return ret; 1216 } 1217 1218 typedef struct BlockReopenQueueEntry { 1219 bool prepared; 1220 BDRVReopenState state; 1221 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; 1222 } BlockReopenQueueEntry; 1223 1224 /* 1225 * Adds a BlockDriverState to a simple queue for an atomic, transactional 1226 * reopen of multiple devices. 1227 * 1228 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT 1229 * already performed, or alternatively may be NULL a new BlockReopenQueue will 1230 * be created and initialized. This newly created BlockReopenQueue should be 1231 * passed back in for subsequent calls that are intended to be of the same 1232 * atomic 'set'. 1233 * 1234 * bs is the BlockDriverState to add to the reopen queue. 1235 * 1236 * flags contains the open flags for the associated bs 1237 * 1238 * returns a pointer to bs_queue, which is either the newly allocated 1239 * bs_queue, or the existing bs_queue being used. 1240 * 1241 */ 1242 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, 1243 BlockDriverState *bs, int flags) 1244 { 1245 assert(bs != NULL); 1246 1247 BlockReopenQueueEntry *bs_entry; 1248 if (bs_queue == NULL) { 1249 bs_queue = g_new0(BlockReopenQueue, 1); 1250 QSIMPLEQ_INIT(bs_queue); 1251 } 1252 1253 if (bs->file) { 1254 bdrv_reopen_queue(bs_queue, bs->file, flags); 1255 } 1256 1257 bs_entry = g_new0(BlockReopenQueueEntry, 1); 1258 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); 1259 1260 bs_entry->state.bs = bs; 1261 bs_entry->state.flags = flags; 1262 1263 return bs_queue; 1264 } 1265 1266 /* 1267 * Reopen multiple BlockDriverStates atomically & transactionally. 1268 * 1269 * The queue passed in (bs_queue) must have been built up previous 1270 * via bdrv_reopen_queue(). 1271 * 1272 * Reopens all BDS specified in the queue, with the appropriate 1273 * flags. All devices are prepared for reopen, and failure of any 1274 * device will cause all device changes to be abandonded, and intermediate 1275 * data cleaned up. 1276 * 1277 * If all devices prepare successfully, then the changes are committed 1278 * to all devices. 1279 * 1280 */ 1281 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) 1282 { 1283 int ret = -1; 1284 BlockReopenQueueEntry *bs_entry, *next; 1285 Error *local_err = NULL; 1286 1287 assert(bs_queue != NULL); 1288 1289 bdrv_drain_all(); 1290 1291 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 1292 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { 1293 error_propagate(errp, local_err); 1294 goto cleanup; 1295 } 1296 bs_entry->prepared = true; 1297 } 1298 1299 /* If we reach this point, we have success and just need to apply the 1300 * changes 1301 */ 1302 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 1303 bdrv_reopen_commit(&bs_entry->state); 1304 } 1305 1306 ret = 0; 1307 1308 cleanup: 1309 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { 1310 if (ret && bs_entry->prepared) { 1311 bdrv_reopen_abort(&bs_entry->state); 1312 } 1313 g_free(bs_entry); 1314 } 1315 g_free(bs_queue); 1316 return ret; 1317 } 1318 1319 1320 /* Reopen a single BlockDriverState with the specified flags. */ 1321 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) 1322 { 1323 int ret = -1; 1324 Error *local_err = NULL; 1325 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, bdrv_flags); 1326 1327 ret = bdrv_reopen_multiple(queue, &local_err); 1328 if (local_err != NULL) { 1329 error_propagate(errp, local_err); 1330 } 1331 return ret; 1332 } 1333 1334 1335 /* 1336 * Prepares a BlockDriverState for reopen. All changes are staged in the 1337 * 'opaque' field of the BDRVReopenState, which is used and allocated by 1338 * the block driver layer .bdrv_reopen_prepare() 1339 * 1340 * bs is the BlockDriverState to reopen 1341 * flags are the new open flags 1342 * queue is the reopen queue 1343 * 1344 * Returns 0 on success, non-zero on error. On error errp will be set 1345 * as well. 1346 * 1347 * On failure, bdrv_reopen_abort() will be called to clean up any data. 1348 * It is the responsibility of the caller to then call the abort() or 1349 * commit() for any other BDS that have been left in a prepare() state 1350 * 1351 */ 1352 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 1353 Error **errp) 1354 { 1355 int ret = -1; 1356 Error *local_err = NULL; 1357 BlockDriver *drv; 1358 1359 assert(reopen_state != NULL); 1360 assert(reopen_state->bs->drv != NULL); 1361 drv = reopen_state->bs->drv; 1362 1363 /* if we are to stay read-only, do not allow permission change 1364 * to r/w */ 1365 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) && 1366 reopen_state->flags & BDRV_O_RDWR) { 1367 error_set(errp, QERR_DEVICE_IS_READ_ONLY, 1368 reopen_state->bs->device_name); 1369 goto error; 1370 } 1371 1372 1373 ret = bdrv_flush(reopen_state->bs); 1374 if (ret) { 1375 error_set(errp, ERROR_CLASS_GENERIC_ERROR, "Error (%s) flushing drive", 1376 strerror(-ret)); 1377 goto error; 1378 } 1379 1380 if (drv->bdrv_reopen_prepare) { 1381 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); 1382 if (ret) { 1383 if (local_err != NULL) { 1384 error_propagate(errp, local_err); 1385 } else { 1386 error_setg(errp, "failed while preparing to reopen image '%s'", 1387 reopen_state->bs->filename); 1388 } 1389 goto error; 1390 } 1391 } else { 1392 /* It is currently mandatory to have a bdrv_reopen_prepare() 1393 * handler for each supported drv. */ 1394 error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 1395 drv->format_name, reopen_state->bs->device_name, 1396 "reopening of file"); 1397 ret = -1; 1398 goto error; 1399 } 1400 1401 ret = 0; 1402 1403 error: 1404 return ret; 1405 } 1406 1407 /* 1408 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and 1409 * makes them final by swapping the staging BlockDriverState contents into 1410 * the active BlockDriverState contents. 1411 */ 1412 void bdrv_reopen_commit(BDRVReopenState *reopen_state) 1413 { 1414 BlockDriver *drv; 1415 1416 assert(reopen_state != NULL); 1417 drv = reopen_state->bs->drv; 1418 assert(drv != NULL); 1419 1420 /* If there are any driver level actions to take */ 1421 if (drv->bdrv_reopen_commit) { 1422 drv->bdrv_reopen_commit(reopen_state); 1423 } 1424 1425 /* set BDS specific flags now */ 1426 reopen_state->bs->open_flags = reopen_state->flags; 1427 reopen_state->bs->enable_write_cache = !!(reopen_state->flags & 1428 BDRV_O_CACHE_WB); 1429 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); 1430 } 1431 1432 /* 1433 * Abort the reopen, and delete and free the staged changes in 1434 * reopen_state 1435 */ 1436 void bdrv_reopen_abort(BDRVReopenState *reopen_state) 1437 { 1438 BlockDriver *drv; 1439 1440 assert(reopen_state != NULL); 1441 drv = reopen_state->bs->drv; 1442 assert(drv != NULL); 1443 1444 if (drv->bdrv_reopen_abort) { 1445 drv->bdrv_reopen_abort(reopen_state); 1446 } 1447 } 1448 1449 1450 void bdrv_close(BlockDriverState *bs) 1451 { 1452 if (bs->job) { 1453 block_job_cancel_sync(bs->job); 1454 } 1455 bdrv_drain_all(); /* complete I/O */ 1456 bdrv_flush(bs); 1457 bdrv_drain_all(); /* in case flush left pending I/O */ 1458 notifier_list_notify(&bs->close_notifiers, bs); 1459 1460 if (bs->drv) { 1461 if (bs->backing_hd) { 1462 bdrv_unref(bs->backing_hd); 1463 bs->backing_hd = NULL; 1464 } 1465 bs->drv->bdrv_close(bs); 1466 g_free(bs->opaque); 1467 #ifdef _WIN32 1468 if (bs->is_temporary) { 1469 unlink(bs->filename); 1470 } 1471 #endif 1472 bs->opaque = NULL; 1473 bs->drv = NULL; 1474 bs->copy_on_read = 0; 1475 bs->backing_file[0] = '\0'; 1476 bs->backing_format[0] = '\0'; 1477 bs->total_sectors = 0; 1478 bs->encrypted = 0; 1479 bs->valid_key = 0; 1480 bs->sg = 0; 1481 bs->growable = 0; 1482 bs->zero_beyond_eof = false; 1483 QDECREF(bs->options); 1484 bs->options = NULL; 1485 1486 if (bs->file != NULL) { 1487 bdrv_unref(bs->file); 1488 bs->file = NULL; 1489 } 1490 } 1491 1492 bdrv_dev_change_media_cb(bs, false); 1493 1494 /*throttling disk I/O limits*/ 1495 if (bs->io_limits_enabled) { 1496 bdrv_io_limits_disable(bs); 1497 } 1498 } 1499 1500 void bdrv_close_all(void) 1501 { 1502 BlockDriverState *bs; 1503 1504 QTAILQ_FOREACH(bs, &bdrv_states, list) { 1505 bdrv_close(bs); 1506 } 1507 } 1508 1509 /* Check if any requests are in-flight (including throttled requests) */ 1510 static bool bdrv_requests_pending(BlockDriverState *bs) 1511 { 1512 if (!QLIST_EMPTY(&bs->tracked_requests)) { 1513 return true; 1514 } 1515 if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) { 1516 return true; 1517 } 1518 if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) { 1519 return true; 1520 } 1521 if (bs->file && bdrv_requests_pending(bs->file)) { 1522 return true; 1523 } 1524 if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) { 1525 return true; 1526 } 1527 return false; 1528 } 1529 1530 static bool bdrv_requests_pending_all(void) 1531 { 1532 BlockDriverState *bs; 1533 QTAILQ_FOREACH(bs, &bdrv_states, list) { 1534 if (bdrv_requests_pending(bs)) { 1535 return true; 1536 } 1537 } 1538 return false; 1539 } 1540 1541 /* 1542 * Wait for pending requests to complete across all BlockDriverStates 1543 * 1544 * This function does not flush data to disk, use bdrv_flush_all() for that 1545 * after calling this function. 1546 * 1547 * Note that completion of an asynchronous I/O operation can trigger any 1548 * number of other I/O operations on other devices---for example a coroutine 1549 * can be arbitrarily complex and a constant flow of I/O can come until the 1550 * coroutine is complete. Because of this, it is not possible to have a 1551 * function to drain a single device's I/O queue. 1552 */ 1553 void bdrv_drain_all(void) 1554 { 1555 /* Always run first iteration so any pending completion BHs run */ 1556 bool busy = true; 1557 BlockDriverState *bs; 1558 1559 while (busy) { 1560 /* FIXME: We do not have timer support here, so this is effectively 1561 * a busy wait. 1562 */ 1563 QTAILQ_FOREACH(bs, &bdrv_states, list) { 1564 if (bdrv_start_throttled_reqs(bs)) { 1565 busy = true; 1566 } 1567 } 1568 1569 busy = bdrv_requests_pending_all(); 1570 busy |= aio_poll(qemu_get_aio_context(), busy); 1571 } 1572 } 1573 1574 /* make a BlockDriverState anonymous by removing from bdrv_state list. 1575 Also, NULL terminate the device_name to prevent double remove */ 1576 void bdrv_make_anon(BlockDriverState *bs) 1577 { 1578 if (bs->device_name[0] != '\0') { 1579 QTAILQ_REMOVE(&bdrv_states, bs, list); 1580 } 1581 bs->device_name[0] = '\0'; 1582 } 1583 1584 static void bdrv_rebind(BlockDriverState *bs) 1585 { 1586 if (bs->drv && bs->drv->bdrv_rebind) { 1587 bs->drv->bdrv_rebind(bs); 1588 } 1589 } 1590 1591 static void bdrv_move_feature_fields(BlockDriverState *bs_dest, 1592 BlockDriverState *bs_src) 1593 { 1594 /* move some fields that need to stay attached to the device */ 1595 bs_dest->open_flags = bs_src->open_flags; 1596 1597 /* dev info */ 1598 bs_dest->dev_ops = bs_src->dev_ops; 1599 bs_dest->dev_opaque = bs_src->dev_opaque; 1600 bs_dest->dev = bs_src->dev; 1601 bs_dest->buffer_alignment = bs_src->buffer_alignment; 1602 bs_dest->copy_on_read = bs_src->copy_on_read; 1603 1604 bs_dest->enable_write_cache = bs_src->enable_write_cache; 1605 1606 /* i/o throttled req */ 1607 memcpy(&bs_dest->throttle_state, 1608 &bs_src->throttle_state, 1609 sizeof(ThrottleState)); 1610 bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; 1611 bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; 1612 bs_dest->io_limits_enabled = bs_src->io_limits_enabled; 1613 1614 /* r/w error */ 1615 bs_dest->on_read_error = bs_src->on_read_error; 1616 bs_dest->on_write_error = bs_src->on_write_error; 1617 1618 /* i/o status */ 1619 bs_dest->iostatus_enabled = bs_src->iostatus_enabled; 1620 bs_dest->iostatus = bs_src->iostatus; 1621 1622 /* dirty bitmap */ 1623 bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps; 1624 1625 /* reference count */ 1626 bs_dest->refcnt = bs_src->refcnt; 1627 1628 /* job */ 1629 bs_dest->in_use = bs_src->in_use; 1630 bs_dest->job = bs_src->job; 1631 1632 /* keep the same entry in bdrv_states */ 1633 pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name), 1634 bs_src->device_name); 1635 bs_dest->list = bs_src->list; 1636 } 1637 1638 /* 1639 * Swap bs contents for two image chains while they are live, 1640 * while keeping required fields on the BlockDriverState that is 1641 * actually attached to a device. 1642 * 1643 * This will modify the BlockDriverState fields, and swap contents 1644 * between bs_new and bs_old. Both bs_new and bs_old are modified. 1645 * 1646 * bs_new is required to be anonymous. 1647 * 1648 * This function does not create any image files. 1649 */ 1650 void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) 1651 { 1652 BlockDriverState tmp; 1653 1654 /* bs_new must be anonymous and shouldn't have anything fancy enabled */ 1655 assert(bs_new->device_name[0] == '\0'); 1656 assert(QLIST_EMPTY(&bs_new->dirty_bitmaps)); 1657 assert(bs_new->job == NULL); 1658 assert(bs_new->dev == NULL); 1659 assert(bs_new->in_use == 0); 1660 assert(bs_new->io_limits_enabled == false); 1661 assert(!throttle_have_timer(&bs_new->throttle_state)); 1662 1663 tmp = *bs_new; 1664 *bs_new = *bs_old; 1665 *bs_old = tmp; 1666 1667 /* there are some fields that should not be swapped, move them back */ 1668 bdrv_move_feature_fields(&tmp, bs_old); 1669 bdrv_move_feature_fields(bs_old, bs_new); 1670 bdrv_move_feature_fields(bs_new, &tmp); 1671 1672 /* bs_new shouldn't be in bdrv_states even after the swap! */ 1673 assert(bs_new->device_name[0] == '\0'); 1674 1675 /* Check a few fields that should remain attached to the device */ 1676 assert(bs_new->dev == NULL); 1677 assert(bs_new->job == NULL); 1678 assert(bs_new->in_use == 0); 1679 assert(bs_new->io_limits_enabled == false); 1680 assert(!throttle_have_timer(&bs_new->throttle_state)); 1681 1682 bdrv_rebind(bs_new); 1683 bdrv_rebind(bs_old); 1684 } 1685 1686 /* 1687 * Add new bs contents at the top of an image chain while the chain is 1688 * live, while keeping required fields on the top layer. 1689 * 1690 * This will modify the BlockDriverState fields, and swap contents 1691 * between bs_new and bs_top. Both bs_new and bs_top are modified. 1692 * 1693 * bs_new is required to be anonymous. 1694 * 1695 * This function does not create any image files. 1696 */ 1697 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) 1698 { 1699 bdrv_swap(bs_new, bs_top); 1700 1701 /* The contents of 'tmp' will become bs_top, as we are 1702 * swapping bs_new and bs_top contents. */ 1703 bs_top->backing_hd = bs_new; 1704 bs_top->open_flags &= ~BDRV_O_NO_BACKING; 1705 pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file), 1706 bs_new->filename); 1707 pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format), 1708 bs_new->drv ? bs_new->drv->format_name : ""); 1709 } 1710 1711 static void bdrv_delete(BlockDriverState *bs) 1712 { 1713 assert(!bs->dev); 1714 assert(!bs->job); 1715 assert(!bs->in_use); 1716 assert(!bs->refcnt); 1717 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 1718 1719 bdrv_close(bs); 1720 1721 /* remove from list, if necessary */ 1722 bdrv_make_anon(bs); 1723 1724 g_free(bs); 1725 } 1726 1727 int bdrv_attach_dev(BlockDriverState *bs, void *dev) 1728 /* TODO change to DeviceState *dev when all users are qdevified */ 1729 { 1730 if (bs->dev) { 1731 return -EBUSY; 1732 } 1733 bs->dev = dev; 1734 bdrv_iostatus_reset(bs); 1735 return 0; 1736 } 1737 1738 /* TODO qdevified devices don't use this, remove when devices are qdevified */ 1739 void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev) 1740 { 1741 if (bdrv_attach_dev(bs, dev) < 0) { 1742 abort(); 1743 } 1744 } 1745 1746 void bdrv_detach_dev(BlockDriverState *bs, void *dev) 1747 /* TODO change to DeviceState *dev when all users are qdevified */ 1748 { 1749 assert(bs->dev == dev); 1750 bs->dev = NULL; 1751 bs->dev_ops = NULL; 1752 bs->dev_opaque = NULL; 1753 bs->buffer_alignment = 512; 1754 } 1755 1756 /* TODO change to return DeviceState * when all users are qdevified */ 1757 void *bdrv_get_attached_dev(BlockDriverState *bs) 1758 { 1759 return bs->dev; 1760 } 1761 1762 void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops, 1763 void *opaque) 1764 { 1765 bs->dev_ops = ops; 1766 bs->dev_opaque = opaque; 1767 } 1768 1769 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv, 1770 enum MonitorEvent ev, 1771 BlockErrorAction action, bool is_read) 1772 { 1773 QObject *data; 1774 const char *action_str; 1775 1776 switch (action) { 1777 case BDRV_ACTION_REPORT: 1778 action_str = "report"; 1779 break; 1780 case BDRV_ACTION_IGNORE: 1781 action_str = "ignore"; 1782 break; 1783 case BDRV_ACTION_STOP: 1784 action_str = "stop"; 1785 break; 1786 default: 1787 abort(); 1788 } 1789 1790 data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }", 1791 bdrv->device_name, 1792 action_str, 1793 is_read ? "read" : "write"); 1794 monitor_protocol_event(ev, data); 1795 1796 qobject_decref(data); 1797 } 1798 1799 static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected) 1800 { 1801 QObject *data; 1802 1803 data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }", 1804 bdrv_get_device_name(bs), ejected); 1805 monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data); 1806 1807 qobject_decref(data); 1808 } 1809 1810 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load) 1811 { 1812 if (bs->dev_ops && bs->dev_ops->change_media_cb) { 1813 bool tray_was_closed = !bdrv_dev_is_tray_open(bs); 1814 bs->dev_ops->change_media_cb(bs->dev_opaque, load); 1815 if (tray_was_closed) { 1816 /* tray open */ 1817 bdrv_emit_qmp_eject_event(bs, true); 1818 } 1819 if (load) { 1820 /* tray close */ 1821 bdrv_emit_qmp_eject_event(bs, false); 1822 } 1823 } 1824 } 1825 1826 bool bdrv_dev_has_removable_media(BlockDriverState *bs) 1827 { 1828 return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb); 1829 } 1830 1831 void bdrv_dev_eject_request(BlockDriverState *bs, bool force) 1832 { 1833 if (bs->dev_ops && bs->dev_ops->eject_request_cb) { 1834 bs->dev_ops->eject_request_cb(bs->dev_opaque, force); 1835 } 1836 } 1837 1838 bool bdrv_dev_is_tray_open(BlockDriverState *bs) 1839 { 1840 if (bs->dev_ops && bs->dev_ops->is_tray_open) { 1841 return bs->dev_ops->is_tray_open(bs->dev_opaque); 1842 } 1843 return false; 1844 } 1845 1846 static void bdrv_dev_resize_cb(BlockDriverState *bs) 1847 { 1848 if (bs->dev_ops && bs->dev_ops->resize_cb) { 1849 bs->dev_ops->resize_cb(bs->dev_opaque); 1850 } 1851 } 1852 1853 bool bdrv_dev_is_medium_locked(BlockDriverState *bs) 1854 { 1855 if (bs->dev_ops && bs->dev_ops->is_medium_locked) { 1856 return bs->dev_ops->is_medium_locked(bs->dev_opaque); 1857 } 1858 return false; 1859 } 1860 1861 /* 1862 * Run consistency checks on an image 1863 * 1864 * Returns 0 if the check could be completed (it doesn't mean that the image is 1865 * free of errors) or -errno when an internal error occurred. The results of the 1866 * check are stored in res. 1867 */ 1868 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) 1869 { 1870 if (bs->drv->bdrv_check == NULL) { 1871 return -ENOTSUP; 1872 } 1873 1874 memset(res, 0, sizeof(*res)); 1875 return bs->drv->bdrv_check(bs, res, fix); 1876 } 1877 1878 #define COMMIT_BUF_SECTORS 2048 1879 1880 /* commit COW file into the raw image */ 1881 int bdrv_commit(BlockDriverState *bs) 1882 { 1883 BlockDriver *drv = bs->drv; 1884 int64_t sector, total_sectors; 1885 int n, ro, open_flags; 1886 int ret = 0; 1887 uint8_t *buf; 1888 char filename[PATH_MAX]; 1889 1890 if (!drv) 1891 return -ENOMEDIUM; 1892 1893 if (!bs->backing_hd) { 1894 return -ENOTSUP; 1895 } 1896 1897 if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) { 1898 return -EBUSY; 1899 } 1900 1901 ro = bs->backing_hd->read_only; 1902 /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */ 1903 pstrcpy(filename, sizeof(filename), bs->backing_hd->filename); 1904 open_flags = bs->backing_hd->open_flags; 1905 1906 if (ro) { 1907 if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) { 1908 return -EACCES; 1909 } 1910 } 1911 1912 total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; 1913 buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); 1914 1915 for (sector = 0; sector < total_sectors; sector += n) { 1916 ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n); 1917 if (ret < 0) { 1918 goto ro_cleanup; 1919 } 1920 if (ret) { 1921 if (bdrv_read(bs, sector, buf, n) != 0) { 1922 ret = -EIO; 1923 goto ro_cleanup; 1924 } 1925 1926 if (bdrv_write(bs->backing_hd, sector, buf, n) != 0) { 1927 ret = -EIO; 1928 goto ro_cleanup; 1929 } 1930 } 1931 } 1932 1933 if (drv->bdrv_make_empty) { 1934 ret = drv->bdrv_make_empty(bs); 1935 bdrv_flush(bs); 1936 } 1937 1938 /* 1939 * Make sure all data we wrote to the backing device is actually 1940 * stable on disk. 1941 */ 1942 if (bs->backing_hd) 1943 bdrv_flush(bs->backing_hd); 1944 1945 ro_cleanup: 1946 g_free(buf); 1947 1948 if (ro) { 1949 /* ignoring error return here */ 1950 bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL); 1951 } 1952 1953 return ret; 1954 } 1955 1956 int bdrv_commit_all(void) 1957 { 1958 BlockDriverState *bs; 1959 1960 QTAILQ_FOREACH(bs, &bdrv_states, list) { 1961 if (bs->drv && bs->backing_hd) { 1962 int ret = bdrv_commit(bs); 1963 if (ret < 0) { 1964 return ret; 1965 } 1966 } 1967 } 1968 return 0; 1969 } 1970 1971 /** 1972 * Remove an active request from the tracked requests list 1973 * 1974 * This function should be called when a tracked request is completing. 1975 */ 1976 static void tracked_request_end(BdrvTrackedRequest *req) 1977 { 1978 QLIST_REMOVE(req, list); 1979 qemu_co_queue_restart_all(&req->wait_queue); 1980 } 1981 1982 /** 1983 * Add an active request to the tracked requests list 1984 */ 1985 static void tracked_request_begin(BdrvTrackedRequest *req, 1986 BlockDriverState *bs, 1987 int64_t sector_num, 1988 int nb_sectors, bool is_write) 1989 { 1990 *req = (BdrvTrackedRequest){ 1991 .bs = bs, 1992 .sector_num = sector_num, 1993 .nb_sectors = nb_sectors, 1994 .is_write = is_write, 1995 .co = qemu_coroutine_self(), 1996 }; 1997 1998 qemu_co_queue_init(&req->wait_queue); 1999 2000 QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); 2001 } 2002 2003 /** 2004 * Round a region to cluster boundaries 2005 */ 2006 void bdrv_round_to_clusters(BlockDriverState *bs, 2007 int64_t sector_num, int nb_sectors, 2008 int64_t *cluster_sector_num, 2009 int *cluster_nb_sectors) 2010 { 2011 BlockDriverInfo bdi; 2012 2013 if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { 2014 *cluster_sector_num = sector_num; 2015 *cluster_nb_sectors = nb_sectors; 2016 } else { 2017 int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE; 2018 *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c); 2019 *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num + 2020 nb_sectors, c); 2021 } 2022 } 2023 2024 static bool tracked_request_overlaps(BdrvTrackedRequest *req, 2025 int64_t sector_num, int nb_sectors) { 2026 /* aaaa bbbb */ 2027 if (sector_num >= req->sector_num + req->nb_sectors) { 2028 return false; 2029 } 2030 /* bbbb aaaa */ 2031 if (req->sector_num >= sector_num + nb_sectors) { 2032 return false; 2033 } 2034 return true; 2035 } 2036 2037 static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs, 2038 int64_t sector_num, int nb_sectors) 2039 { 2040 BdrvTrackedRequest *req; 2041 int64_t cluster_sector_num; 2042 int cluster_nb_sectors; 2043 bool retry; 2044 2045 /* If we touch the same cluster it counts as an overlap. This guarantees 2046 * that allocating writes will be serialized and not race with each other 2047 * for the same cluster. For example, in copy-on-read it ensures that the 2048 * CoR read and write operations are atomic and guest writes cannot 2049 * interleave between them. 2050 */ 2051 bdrv_round_to_clusters(bs, sector_num, nb_sectors, 2052 &cluster_sector_num, &cluster_nb_sectors); 2053 2054 do { 2055 retry = false; 2056 QLIST_FOREACH(req, &bs->tracked_requests, list) { 2057 if (tracked_request_overlaps(req, cluster_sector_num, 2058 cluster_nb_sectors)) { 2059 /* Hitting this means there was a reentrant request, for 2060 * example, a block driver issuing nested requests. This must 2061 * never happen since it means deadlock. 2062 */ 2063 assert(qemu_coroutine_self() != req->co); 2064 2065 qemu_co_queue_wait(&req->wait_queue); 2066 retry = true; 2067 break; 2068 } 2069 } 2070 } while (retry); 2071 } 2072 2073 /* 2074 * Return values: 2075 * 0 - success 2076 * -EINVAL - backing format specified, but no file 2077 * -ENOSPC - can't update the backing file because no space is left in the 2078 * image file header 2079 * -ENOTSUP - format driver doesn't support changing the backing file 2080 */ 2081 int bdrv_change_backing_file(BlockDriverState *bs, 2082 const char *backing_file, const char *backing_fmt) 2083 { 2084 BlockDriver *drv = bs->drv; 2085 int ret; 2086 2087 /* Backing file format doesn't make sense without a backing file */ 2088 if (backing_fmt && !backing_file) { 2089 return -EINVAL; 2090 } 2091 2092 if (drv->bdrv_change_backing_file != NULL) { 2093 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); 2094 } else { 2095 ret = -ENOTSUP; 2096 } 2097 2098 if (ret == 0) { 2099 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2100 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2101 } 2102 return ret; 2103 } 2104 2105 /* 2106 * Finds the image layer in the chain that has 'bs' as its backing file. 2107 * 2108 * active is the current topmost image. 2109 * 2110 * Returns NULL if bs is not found in active's image chain, 2111 * or if active == bs. 2112 */ 2113 BlockDriverState *bdrv_find_overlay(BlockDriverState *active, 2114 BlockDriverState *bs) 2115 { 2116 BlockDriverState *overlay = NULL; 2117 BlockDriverState *intermediate; 2118 2119 assert(active != NULL); 2120 assert(bs != NULL); 2121 2122 /* if bs is the same as active, then by definition it has no overlay 2123 */ 2124 if (active == bs) { 2125 return NULL; 2126 } 2127 2128 intermediate = active; 2129 while (intermediate->backing_hd) { 2130 if (intermediate->backing_hd == bs) { 2131 overlay = intermediate; 2132 break; 2133 } 2134 intermediate = intermediate->backing_hd; 2135 } 2136 2137 return overlay; 2138 } 2139 2140 typedef struct BlkIntermediateStates { 2141 BlockDriverState *bs; 2142 QSIMPLEQ_ENTRY(BlkIntermediateStates) entry; 2143 } BlkIntermediateStates; 2144 2145 2146 /* 2147 * Drops images above 'base' up to and including 'top', and sets the image 2148 * above 'top' to have base as its backing file. 2149 * 2150 * Requires that the overlay to 'top' is opened r/w, so that the backing file 2151 * information in 'bs' can be properly updated. 2152 * 2153 * E.g., this will convert the following chain: 2154 * bottom <- base <- intermediate <- top <- active 2155 * 2156 * to 2157 * 2158 * bottom <- base <- active 2159 * 2160 * It is allowed for bottom==base, in which case it converts: 2161 * 2162 * base <- intermediate <- top <- active 2163 * 2164 * to 2165 * 2166 * base <- active 2167 * 2168 * Error conditions: 2169 * if active == top, that is considered an error 2170 * 2171 */ 2172 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, 2173 BlockDriverState *base) 2174 { 2175 BlockDriverState *intermediate; 2176 BlockDriverState *base_bs = NULL; 2177 BlockDriverState *new_top_bs = NULL; 2178 BlkIntermediateStates *intermediate_state, *next; 2179 int ret = -EIO; 2180 2181 QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete; 2182 QSIMPLEQ_INIT(&states_to_delete); 2183 2184 if (!top->drv || !base->drv) { 2185 goto exit; 2186 } 2187 2188 new_top_bs = bdrv_find_overlay(active, top); 2189 2190 if (new_top_bs == NULL) { 2191 /* we could not find the image above 'top', this is an error */ 2192 goto exit; 2193 } 2194 2195 /* special case of new_top_bs->backing_hd already pointing to base - nothing 2196 * to do, no intermediate images */ 2197 if (new_top_bs->backing_hd == base) { 2198 ret = 0; 2199 goto exit; 2200 } 2201 2202 intermediate = top; 2203 2204 /* now we will go down through the list, and add each BDS we find 2205 * into our deletion queue, until we hit the 'base' 2206 */ 2207 while (intermediate) { 2208 intermediate_state = g_malloc0(sizeof(BlkIntermediateStates)); 2209 intermediate_state->bs = intermediate; 2210 QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry); 2211 2212 if (intermediate->backing_hd == base) { 2213 base_bs = intermediate->backing_hd; 2214 break; 2215 } 2216 intermediate = intermediate->backing_hd; 2217 } 2218 if (base_bs == NULL) { 2219 /* something went wrong, we did not end at the base. safely 2220 * unravel everything, and exit with error */ 2221 goto exit; 2222 } 2223 2224 /* success - we can delete the intermediate states, and link top->base */ 2225 ret = bdrv_change_backing_file(new_top_bs, base_bs->filename, 2226 base_bs->drv ? base_bs->drv->format_name : ""); 2227 if (ret) { 2228 goto exit; 2229 } 2230 new_top_bs->backing_hd = base_bs; 2231 2232 2233 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2234 /* so that bdrv_close() does not recursively close the chain */ 2235 intermediate_state->bs->backing_hd = NULL; 2236 bdrv_unref(intermediate_state->bs); 2237 } 2238 ret = 0; 2239 2240 exit: 2241 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2242 g_free(intermediate_state); 2243 } 2244 return ret; 2245 } 2246 2247 2248 static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, 2249 size_t size) 2250 { 2251 int64_t len; 2252 2253 if (!bdrv_is_inserted(bs)) 2254 return -ENOMEDIUM; 2255 2256 if (bs->growable) 2257 return 0; 2258 2259 len = bdrv_getlength(bs); 2260 2261 if (offset < 0) 2262 return -EIO; 2263 2264 if ((offset > len) || (len - offset < size)) 2265 return -EIO; 2266 2267 return 0; 2268 } 2269 2270 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, 2271 int nb_sectors) 2272 { 2273 return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE, 2274 nb_sectors * BDRV_SECTOR_SIZE); 2275 } 2276 2277 typedef struct RwCo { 2278 BlockDriverState *bs; 2279 int64_t sector_num; 2280 int nb_sectors; 2281 QEMUIOVector *qiov; 2282 bool is_write; 2283 int ret; 2284 BdrvRequestFlags flags; 2285 } RwCo; 2286 2287 static void coroutine_fn bdrv_rw_co_entry(void *opaque) 2288 { 2289 RwCo *rwco = opaque; 2290 2291 if (!rwco->is_write) { 2292 rwco->ret = bdrv_co_do_readv(rwco->bs, rwco->sector_num, 2293 rwco->nb_sectors, rwco->qiov, 2294 rwco->flags); 2295 } else { 2296 rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num, 2297 rwco->nb_sectors, rwco->qiov, 2298 rwco->flags); 2299 } 2300 } 2301 2302 /* 2303 * Process a vectored synchronous request using coroutines 2304 */ 2305 static int bdrv_rwv_co(BlockDriverState *bs, int64_t sector_num, 2306 QEMUIOVector *qiov, bool is_write, 2307 BdrvRequestFlags flags) 2308 { 2309 Coroutine *co; 2310 RwCo rwco = { 2311 .bs = bs, 2312 .sector_num = sector_num, 2313 .nb_sectors = qiov->size >> BDRV_SECTOR_BITS, 2314 .qiov = qiov, 2315 .is_write = is_write, 2316 .ret = NOT_DONE, 2317 .flags = flags, 2318 }; 2319 assert((qiov->size & (BDRV_SECTOR_SIZE - 1)) == 0); 2320 2321 /** 2322 * In sync call context, when the vcpu is blocked, this throttling timer 2323 * will not fire; so the I/O throttling function has to be disabled here 2324 * if it has been enabled. 2325 */ 2326 if (bs->io_limits_enabled) { 2327 fprintf(stderr, "Disabling I/O throttling on '%s' due " 2328 "to synchronous I/O.\n", bdrv_get_device_name(bs)); 2329 bdrv_io_limits_disable(bs); 2330 } 2331 2332 if (qemu_in_coroutine()) { 2333 /* Fast-path if already in coroutine context */ 2334 bdrv_rw_co_entry(&rwco); 2335 } else { 2336 co = qemu_coroutine_create(bdrv_rw_co_entry); 2337 qemu_coroutine_enter(co, &rwco); 2338 while (rwco.ret == NOT_DONE) { 2339 qemu_aio_wait(); 2340 } 2341 } 2342 return rwco.ret; 2343 } 2344 2345 /* 2346 * Process a synchronous request using coroutines 2347 */ 2348 static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, 2349 int nb_sectors, bool is_write, BdrvRequestFlags flags) 2350 { 2351 QEMUIOVector qiov; 2352 struct iovec iov = { 2353 .iov_base = (void *)buf, 2354 .iov_len = nb_sectors * BDRV_SECTOR_SIZE, 2355 }; 2356 2357 qemu_iovec_init_external(&qiov, &iov, 1); 2358 return bdrv_rwv_co(bs, sector_num, &qiov, is_write, flags); 2359 } 2360 2361 /* return < 0 if error. See bdrv_write() for the return codes */ 2362 int bdrv_read(BlockDriverState *bs, int64_t sector_num, 2363 uint8_t *buf, int nb_sectors) 2364 { 2365 return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0); 2366 } 2367 2368 /* Just like bdrv_read(), but with I/O throttling temporarily disabled */ 2369 int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, 2370 uint8_t *buf, int nb_sectors) 2371 { 2372 bool enabled; 2373 int ret; 2374 2375 enabled = bs->io_limits_enabled; 2376 bs->io_limits_enabled = false; 2377 ret = bdrv_read(bs, sector_num, buf, nb_sectors); 2378 bs->io_limits_enabled = enabled; 2379 return ret; 2380 } 2381 2382 /* Return < 0 if error. Important errors are: 2383 -EIO generic I/O error (may happen for all errors) 2384 -ENOMEDIUM No media inserted. 2385 -EINVAL Invalid sector number or nb_sectors 2386 -EACCES Trying to write a read-only device 2387 */ 2388 int bdrv_write(BlockDriverState *bs, int64_t sector_num, 2389 const uint8_t *buf, int nb_sectors) 2390 { 2391 return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0); 2392 } 2393 2394 int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov) 2395 { 2396 return bdrv_rwv_co(bs, sector_num, qiov, true, 0); 2397 } 2398 2399 int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, 2400 int nb_sectors, BdrvRequestFlags flags) 2401 { 2402 return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true, 2403 BDRV_REQ_ZERO_WRITE | flags); 2404 } 2405 2406 /* 2407 * Completely zero out a block device with the help of bdrv_write_zeroes. 2408 * The operation is sped up by checking the block status and only writing 2409 * zeroes to the device if they currently do not return zeroes. Optional 2410 * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). 2411 * 2412 * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). 2413 */ 2414 int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) 2415 { 2416 int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; 2417 int64_t ret, nb_sectors, sector_num = 0; 2418 int n; 2419 2420 for (;;) { 2421 nb_sectors = target_size - sector_num; 2422 if (nb_sectors <= 0) { 2423 return 0; 2424 } 2425 if (nb_sectors > INT_MAX) { 2426 nb_sectors = INT_MAX; 2427 } 2428 ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); 2429 if (ret & BDRV_BLOCK_ZERO) { 2430 sector_num += n; 2431 continue; 2432 } 2433 ret = bdrv_write_zeroes(bs, sector_num, n, flags); 2434 if (ret < 0) { 2435 error_report("error writing zeroes at sector %" PRId64 ": %s", 2436 sector_num, strerror(-ret)); 2437 return ret; 2438 } 2439 sector_num += n; 2440 } 2441 } 2442 2443 int bdrv_pread(BlockDriverState *bs, int64_t offset, 2444 void *buf, int count1) 2445 { 2446 uint8_t tmp_buf[BDRV_SECTOR_SIZE]; 2447 int len, nb_sectors, count; 2448 int64_t sector_num; 2449 int ret; 2450 2451 count = count1; 2452 /* first read to align to sector start */ 2453 len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1); 2454 if (len > count) 2455 len = count; 2456 sector_num = offset >> BDRV_SECTOR_BITS; 2457 if (len > 0) { 2458 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2459 return ret; 2460 memcpy(buf, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), len); 2461 count -= len; 2462 if (count == 0) 2463 return count1; 2464 sector_num++; 2465 buf += len; 2466 } 2467 2468 /* read the sectors "in place" */ 2469 nb_sectors = count >> BDRV_SECTOR_BITS; 2470 if (nb_sectors > 0) { 2471 if ((ret = bdrv_read(bs, sector_num, buf, nb_sectors)) < 0) 2472 return ret; 2473 sector_num += nb_sectors; 2474 len = nb_sectors << BDRV_SECTOR_BITS; 2475 buf += len; 2476 count -= len; 2477 } 2478 2479 /* add data from the last sector */ 2480 if (count > 0) { 2481 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2482 return ret; 2483 memcpy(buf, tmp_buf, count); 2484 } 2485 return count1; 2486 } 2487 2488 int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov) 2489 { 2490 uint8_t tmp_buf[BDRV_SECTOR_SIZE]; 2491 int len, nb_sectors, count; 2492 int64_t sector_num; 2493 int ret; 2494 2495 count = qiov->size; 2496 2497 /* first write to align to sector start */ 2498 len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1); 2499 if (len > count) 2500 len = count; 2501 sector_num = offset >> BDRV_SECTOR_BITS; 2502 if (len > 0) { 2503 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2504 return ret; 2505 qemu_iovec_to_buf(qiov, 0, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), 2506 len); 2507 if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0) 2508 return ret; 2509 count -= len; 2510 if (count == 0) 2511 return qiov->size; 2512 sector_num++; 2513 } 2514 2515 /* write the sectors "in place" */ 2516 nb_sectors = count >> BDRV_SECTOR_BITS; 2517 if (nb_sectors > 0) { 2518 QEMUIOVector qiov_inplace; 2519 2520 qemu_iovec_init(&qiov_inplace, qiov->niov); 2521 qemu_iovec_concat(&qiov_inplace, qiov, len, 2522 nb_sectors << BDRV_SECTOR_BITS); 2523 ret = bdrv_writev(bs, sector_num, &qiov_inplace); 2524 qemu_iovec_destroy(&qiov_inplace); 2525 if (ret < 0) { 2526 return ret; 2527 } 2528 2529 sector_num += nb_sectors; 2530 len = nb_sectors << BDRV_SECTOR_BITS; 2531 count -= len; 2532 } 2533 2534 /* add data from the last sector */ 2535 if (count > 0) { 2536 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2537 return ret; 2538 qemu_iovec_to_buf(qiov, qiov->size - count, tmp_buf, count); 2539 if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0) 2540 return ret; 2541 } 2542 return qiov->size; 2543 } 2544 2545 int bdrv_pwrite(BlockDriverState *bs, int64_t offset, 2546 const void *buf, int count1) 2547 { 2548 QEMUIOVector qiov; 2549 struct iovec iov = { 2550 .iov_base = (void *) buf, 2551 .iov_len = count1, 2552 }; 2553 2554 qemu_iovec_init_external(&qiov, &iov, 1); 2555 return bdrv_pwritev(bs, offset, &qiov); 2556 } 2557 2558 /* 2559 * Writes to the file and ensures that no writes are reordered across this 2560 * request (acts as a barrier) 2561 * 2562 * Returns 0 on success, -errno in error cases. 2563 */ 2564 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, 2565 const void *buf, int count) 2566 { 2567 int ret; 2568 2569 ret = bdrv_pwrite(bs, offset, buf, count); 2570 if (ret < 0) { 2571 return ret; 2572 } 2573 2574 /* No flush needed for cache modes that already do it */ 2575 if (bs->enable_write_cache) { 2576 bdrv_flush(bs); 2577 } 2578 2579 return 0; 2580 } 2581 2582 static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, 2583 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) 2584 { 2585 /* Perform I/O through a temporary buffer so that users who scribble over 2586 * their read buffer while the operation is in progress do not end up 2587 * modifying the image file. This is critical for zero-copy guest I/O 2588 * where anything might happen inside guest memory. 2589 */ 2590 void *bounce_buffer; 2591 2592 BlockDriver *drv = bs->drv; 2593 struct iovec iov; 2594 QEMUIOVector bounce_qiov; 2595 int64_t cluster_sector_num; 2596 int cluster_nb_sectors; 2597 size_t skip_bytes; 2598 int ret; 2599 2600 /* Cover entire cluster so no additional backing file I/O is required when 2601 * allocating cluster in the image file. 2602 */ 2603 bdrv_round_to_clusters(bs, sector_num, nb_sectors, 2604 &cluster_sector_num, &cluster_nb_sectors); 2605 2606 trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, 2607 cluster_sector_num, cluster_nb_sectors); 2608 2609 iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE; 2610 iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len); 2611 qemu_iovec_init_external(&bounce_qiov, &iov, 1); 2612 2613 ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors, 2614 &bounce_qiov); 2615 if (ret < 0) { 2616 goto err; 2617 } 2618 2619 if (drv->bdrv_co_write_zeroes && 2620 buffer_is_zero(bounce_buffer, iov.iov_len)) { 2621 ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, 2622 cluster_nb_sectors, 0); 2623 } else { 2624 /* This does not change the data on the disk, it is not necessary 2625 * to flush even in cache=writethrough mode. 2626 */ 2627 ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, 2628 &bounce_qiov); 2629 } 2630 2631 if (ret < 0) { 2632 /* It might be okay to ignore write errors for guest requests. If this 2633 * is a deliberate copy-on-read then we don't want to ignore the error. 2634 * Simply report it in all cases. 2635 */ 2636 goto err; 2637 } 2638 2639 skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE; 2640 qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, 2641 nb_sectors * BDRV_SECTOR_SIZE); 2642 2643 err: 2644 qemu_vfree(bounce_buffer); 2645 return ret; 2646 } 2647 2648 /* 2649 * Handle a read request in coroutine context 2650 */ 2651 static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, 2652 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 2653 BdrvRequestFlags flags) 2654 { 2655 BlockDriver *drv = bs->drv; 2656 BdrvTrackedRequest req; 2657 int ret; 2658 2659 if (!drv) { 2660 return -ENOMEDIUM; 2661 } 2662 if (bdrv_check_request(bs, sector_num, nb_sectors)) { 2663 return -EIO; 2664 } 2665 2666 if (bs->copy_on_read) { 2667 flags |= BDRV_REQ_COPY_ON_READ; 2668 } 2669 if (flags & BDRV_REQ_COPY_ON_READ) { 2670 bs->copy_on_read_in_flight++; 2671 } 2672 2673 if (bs->copy_on_read_in_flight) { 2674 wait_for_overlapping_requests(bs, sector_num, nb_sectors); 2675 } 2676 2677 /* throttling disk I/O */ 2678 if (bs->io_limits_enabled) { 2679 bdrv_io_limits_intercept(bs, nb_sectors, false); 2680 } 2681 2682 tracked_request_begin(&req, bs, sector_num, nb_sectors, false); 2683 2684 if (flags & BDRV_REQ_COPY_ON_READ) { 2685 int pnum; 2686 2687 ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum); 2688 if (ret < 0) { 2689 goto out; 2690 } 2691 2692 if (!ret || pnum != nb_sectors) { 2693 ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov); 2694 goto out; 2695 } 2696 } 2697 2698 if (!(bs->zero_beyond_eof && bs->growable)) { 2699 ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); 2700 } else { 2701 /* Read zeros after EOF of growable BDSes */ 2702 int64_t len, total_sectors, max_nb_sectors; 2703 2704 len = bdrv_getlength(bs); 2705 if (len < 0) { 2706 ret = len; 2707 goto out; 2708 } 2709 2710 total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE); 2711 max_nb_sectors = MAX(0, total_sectors - sector_num); 2712 if (max_nb_sectors > 0) { 2713 ret = drv->bdrv_co_readv(bs, sector_num, 2714 MIN(nb_sectors, max_nb_sectors), qiov); 2715 } else { 2716 ret = 0; 2717 } 2718 2719 /* Reading beyond end of file is supposed to produce zeroes */ 2720 if (ret == 0 && total_sectors < sector_num + nb_sectors) { 2721 uint64_t offset = MAX(0, total_sectors - sector_num); 2722 uint64_t bytes = (sector_num + nb_sectors - offset) * 2723 BDRV_SECTOR_SIZE; 2724 qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes); 2725 } 2726 } 2727 2728 out: 2729 tracked_request_end(&req); 2730 2731 if (flags & BDRV_REQ_COPY_ON_READ) { 2732 bs->copy_on_read_in_flight--; 2733 } 2734 2735 return ret; 2736 } 2737 2738 int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, 2739 int nb_sectors, QEMUIOVector *qiov) 2740 { 2741 trace_bdrv_co_readv(bs, sector_num, nb_sectors); 2742 2743 return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0); 2744 } 2745 2746 int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, 2747 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) 2748 { 2749 trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors); 2750 2751 return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 2752 BDRV_REQ_COPY_ON_READ); 2753 } 2754 2755 /* if no limit is specified in the BlockLimits use a default 2756 * of 32768 512-byte sectors (16 MiB) per request. 2757 */ 2758 #define MAX_WRITE_ZEROES_DEFAULT 32768 2759 2760 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, 2761 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2762 { 2763 BlockDriver *drv = bs->drv; 2764 QEMUIOVector qiov; 2765 struct iovec iov = {0}; 2766 int ret = 0; 2767 2768 int max_write_zeroes = bs->bl.max_write_zeroes ? 2769 bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT; 2770 2771 while (nb_sectors > 0 && !ret) { 2772 int num = nb_sectors; 2773 2774 /* align request */ 2775 if (bs->bl.write_zeroes_alignment && 2776 num >= bs->bl.write_zeroes_alignment && 2777 sector_num % bs->bl.write_zeroes_alignment) { 2778 if (num > bs->bl.write_zeroes_alignment) { 2779 num = bs->bl.write_zeroes_alignment; 2780 } 2781 num -= sector_num % bs->bl.write_zeroes_alignment; 2782 } 2783 2784 /* limit request size */ 2785 if (num > max_write_zeroes) { 2786 num = max_write_zeroes; 2787 } 2788 2789 ret = -ENOTSUP; 2790 /* First try the efficient write zeroes operation */ 2791 if (drv->bdrv_co_write_zeroes) { 2792 ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags); 2793 } 2794 2795 if (ret == -ENOTSUP) { 2796 /* Fall back to bounce buffer if write zeroes is unsupported */ 2797 iov.iov_len = num * BDRV_SECTOR_SIZE; 2798 if (iov.iov_base == NULL) { 2799 /* allocate bounce buffer only once and ensure that it 2800 * is big enough for this and all future requests. 2801 */ 2802 size_t bufsize = num <= nb_sectors ? num : max_write_zeroes; 2803 iov.iov_base = qemu_blockalign(bs, bufsize * BDRV_SECTOR_SIZE); 2804 memset(iov.iov_base, 0, bufsize * BDRV_SECTOR_SIZE); 2805 } 2806 qemu_iovec_init_external(&qiov, &iov, 1); 2807 2808 ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov); 2809 } 2810 2811 sector_num += num; 2812 nb_sectors -= num; 2813 } 2814 2815 qemu_vfree(iov.iov_base); 2816 return ret; 2817 } 2818 2819 /* 2820 * Handle a write request in coroutine context 2821 */ 2822 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 2823 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 2824 BdrvRequestFlags flags) 2825 { 2826 BlockDriver *drv = bs->drv; 2827 BdrvTrackedRequest req; 2828 int ret; 2829 2830 if (!bs->drv) { 2831 return -ENOMEDIUM; 2832 } 2833 if (bs->read_only) { 2834 return -EACCES; 2835 } 2836 if (bdrv_check_request(bs, sector_num, nb_sectors)) { 2837 return -EIO; 2838 } 2839 2840 if (bs->copy_on_read_in_flight) { 2841 wait_for_overlapping_requests(bs, sector_num, nb_sectors); 2842 } 2843 2844 /* throttling disk I/O */ 2845 if (bs->io_limits_enabled) { 2846 bdrv_io_limits_intercept(bs, nb_sectors, true); 2847 } 2848 2849 tracked_request_begin(&req, bs, sector_num, nb_sectors, true); 2850 2851 ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req); 2852 2853 if (ret < 0) { 2854 /* Do nothing, write notifier decided to fail this request */ 2855 } else if (flags & BDRV_REQ_ZERO_WRITE) { 2856 ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); 2857 } else { 2858 ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); 2859 } 2860 2861 if (ret == 0 && !bs->enable_write_cache) { 2862 ret = bdrv_co_flush(bs); 2863 } 2864 2865 bdrv_set_dirty(bs, sector_num, nb_sectors); 2866 2867 if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { 2868 bs->wr_highest_sector = sector_num + nb_sectors - 1; 2869 } 2870 if (bs->growable && ret >= 0) { 2871 bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); 2872 } 2873 2874 tracked_request_end(&req); 2875 2876 return ret; 2877 } 2878 2879 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, 2880 int nb_sectors, QEMUIOVector *qiov) 2881 { 2882 trace_bdrv_co_writev(bs, sector_num, nb_sectors); 2883 2884 return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0); 2885 } 2886 2887 int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, 2888 int64_t sector_num, int nb_sectors, 2889 BdrvRequestFlags flags) 2890 { 2891 trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags); 2892 2893 if (!(bs->open_flags & BDRV_O_UNMAP)) { 2894 flags &= ~BDRV_REQ_MAY_UNMAP; 2895 } 2896 2897 return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, 2898 BDRV_REQ_ZERO_WRITE | flags); 2899 } 2900 2901 /** 2902 * Truncate file to 'offset' bytes (needed only for file protocols) 2903 */ 2904 int bdrv_truncate(BlockDriverState *bs, int64_t offset) 2905 { 2906 BlockDriver *drv = bs->drv; 2907 int ret; 2908 if (!drv) 2909 return -ENOMEDIUM; 2910 if (!drv->bdrv_truncate) 2911 return -ENOTSUP; 2912 if (bs->read_only) 2913 return -EACCES; 2914 if (bdrv_in_use(bs)) 2915 return -EBUSY; 2916 ret = drv->bdrv_truncate(bs, offset); 2917 if (ret == 0) { 2918 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); 2919 bdrv_dev_resize_cb(bs); 2920 } 2921 return ret; 2922 } 2923 2924 /** 2925 * Length of a allocated file in bytes. Sparse files are counted by actual 2926 * allocated space. Return < 0 if error or unknown. 2927 */ 2928 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) 2929 { 2930 BlockDriver *drv = bs->drv; 2931 if (!drv) { 2932 return -ENOMEDIUM; 2933 } 2934 if (drv->bdrv_get_allocated_file_size) { 2935 return drv->bdrv_get_allocated_file_size(bs); 2936 } 2937 if (bs->file) { 2938 return bdrv_get_allocated_file_size(bs->file); 2939 } 2940 return -ENOTSUP; 2941 } 2942 2943 /** 2944 * Length of a file in bytes. Return < 0 if error or unknown. 2945 */ 2946 int64_t bdrv_getlength(BlockDriverState *bs) 2947 { 2948 BlockDriver *drv = bs->drv; 2949 if (!drv) 2950 return -ENOMEDIUM; 2951 2952 if (drv->has_variable_length) { 2953 int ret = refresh_total_sectors(bs, bs->total_sectors); 2954 if (ret < 0) { 2955 return ret; 2956 } 2957 } 2958 return bs->total_sectors * BDRV_SECTOR_SIZE; 2959 } 2960 2961 /* return 0 as number of sectors if no device present or error */ 2962 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) 2963 { 2964 int64_t length; 2965 length = bdrv_getlength(bs); 2966 if (length < 0) 2967 length = 0; 2968 else 2969 length = length >> BDRV_SECTOR_BITS; 2970 *nb_sectors_ptr = length; 2971 } 2972 2973 void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error, 2974 BlockdevOnError on_write_error) 2975 { 2976 bs->on_read_error = on_read_error; 2977 bs->on_write_error = on_write_error; 2978 } 2979 2980 BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read) 2981 { 2982 return is_read ? bs->on_read_error : bs->on_write_error; 2983 } 2984 2985 BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error) 2986 { 2987 BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error; 2988 2989 switch (on_err) { 2990 case BLOCKDEV_ON_ERROR_ENOSPC: 2991 return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT; 2992 case BLOCKDEV_ON_ERROR_STOP: 2993 return BDRV_ACTION_STOP; 2994 case BLOCKDEV_ON_ERROR_REPORT: 2995 return BDRV_ACTION_REPORT; 2996 case BLOCKDEV_ON_ERROR_IGNORE: 2997 return BDRV_ACTION_IGNORE; 2998 default: 2999 abort(); 3000 } 3001 } 3002 3003 /* This is done by device models because, while the block layer knows 3004 * about the error, it does not know whether an operation comes from 3005 * the device or the block layer (from a job, for example). 3006 */ 3007 void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action, 3008 bool is_read, int error) 3009 { 3010 assert(error >= 0); 3011 bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read); 3012 if (action == BDRV_ACTION_STOP) { 3013 vm_stop(RUN_STATE_IO_ERROR); 3014 bdrv_iostatus_set_err(bs, error); 3015 } 3016 } 3017 3018 int bdrv_is_read_only(BlockDriverState *bs) 3019 { 3020 return bs->read_only; 3021 } 3022 3023 int bdrv_is_sg(BlockDriverState *bs) 3024 { 3025 return bs->sg; 3026 } 3027 3028 int bdrv_enable_write_cache(BlockDriverState *bs) 3029 { 3030 return bs->enable_write_cache; 3031 } 3032 3033 void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce) 3034 { 3035 bs->enable_write_cache = wce; 3036 3037 /* so a reopen() will preserve wce */ 3038 if (wce) { 3039 bs->open_flags |= BDRV_O_CACHE_WB; 3040 } else { 3041 bs->open_flags &= ~BDRV_O_CACHE_WB; 3042 } 3043 } 3044 3045 int bdrv_is_encrypted(BlockDriverState *bs) 3046 { 3047 if (bs->backing_hd && bs->backing_hd->encrypted) 3048 return 1; 3049 return bs->encrypted; 3050 } 3051 3052 int bdrv_key_required(BlockDriverState *bs) 3053 { 3054 BlockDriverState *backing_hd = bs->backing_hd; 3055 3056 if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key) 3057 return 1; 3058 return (bs->encrypted && !bs->valid_key); 3059 } 3060 3061 int bdrv_set_key(BlockDriverState *bs, const char *key) 3062 { 3063 int ret; 3064 if (bs->backing_hd && bs->backing_hd->encrypted) { 3065 ret = bdrv_set_key(bs->backing_hd, key); 3066 if (ret < 0) 3067 return ret; 3068 if (!bs->encrypted) 3069 return 0; 3070 } 3071 if (!bs->encrypted) { 3072 return -EINVAL; 3073 } else if (!bs->drv || !bs->drv->bdrv_set_key) { 3074 return -ENOMEDIUM; 3075 } 3076 ret = bs->drv->bdrv_set_key(bs, key); 3077 if (ret < 0) { 3078 bs->valid_key = 0; 3079 } else if (!bs->valid_key) { 3080 bs->valid_key = 1; 3081 /* call the change callback now, we skipped it on open */ 3082 bdrv_dev_change_media_cb(bs, true); 3083 } 3084 return ret; 3085 } 3086 3087 const char *bdrv_get_format_name(BlockDriverState *bs) 3088 { 3089 return bs->drv ? bs->drv->format_name : NULL; 3090 } 3091 3092 void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 3093 void *opaque) 3094 { 3095 BlockDriver *drv; 3096 3097 QLIST_FOREACH(drv, &bdrv_drivers, list) { 3098 it(opaque, drv->format_name); 3099 } 3100 } 3101 3102 BlockDriverState *bdrv_find(const char *name) 3103 { 3104 BlockDriverState *bs; 3105 3106 QTAILQ_FOREACH(bs, &bdrv_states, list) { 3107 if (!strcmp(name, bs->device_name)) { 3108 return bs; 3109 } 3110 } 3111 return NULL; 3112 } 3113 3114 BlockDriverState *bdrv_next(BlockDriverState *bs) 3115 { 3116 if (!bs) { 3117 return QTAILQ_FIRST(&bdrv_states); 3118 } 3119 return QTAILQ_NEXT(bs, list); 3120 } 3121 3122 void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque) 3123 { 3124 BlockDriverState *bs; 3125 3126 QTAILQ_FOREACH(bs, &bdrv_states, list) { 3127 it(opaque, bs); 3128 } 3129 } 3130 3131 const char *bdrv_get_device_name(BlockDriverState *bs) 3132 { 3133 return bs->device_name; 3134 } 3135 3136 int bdrv_get_flags(BlockDriverState *bs) 3137 { 3138 return bs->open_flags; 3139 } 3140 3141 int bdrv_flush_all(void) 3142 { 3143 BlockDriverState *bs; 3144 int result = 0; 3145 3146 QTAILQ_FOREACH(bs, &bdrv_states, list) { 3147 int ret = bdrv_flush(bs); 3148 if (ret < 0 && !result) { 3149 result = ret; 3150 } 3151 } 3152 3153 return result; 3154 } 3155 3156 int bdrv_has_zero_init_1(BlockDriverState *bs) 3157 { 3158 return 1; 3159 } 3160 3161 int bdrv_has_zero_init(BlockDriverState *bs) 3162 { 3163 assert(bs->drv); 3164 3165 /* If BS is a copy on write image, it is initialized to 3166 the contents of the base image, which may not be zeroes. */ 3167 if (bs->backing_hd) { 3168 return 0; 3169 } 3170 if (bs->drv->bdrv_has_zero_init) { 3171 return bs->drv->bdrv_has_zero_init(bs); 3172 } 3173 3174 /* safe default */ 3175 return 0; 3176 } 3177 3178 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) 3179 { 3180 BlockDriverInfo bdi; 3181 3182 if (bs->backing_hd) { 3183 return false; 3184 } 3185 3186 if (bdrv_get_info(bs, &bdi) == 0) { 3187 return bdi.unallocated_blocks_are_zero; 3188 } 3189 3190 return false; 3191 } 3192 3193 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) 3194 { 3195 BlockDriverInfo bdi; 3196 3197 if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { 3198 return false; 3199 } 3200 3201 if (bdrv_get_info(bs, &bdi) == 0) { 3202 return bdi.can_write_zeroes_with_unmap; 3203 } 3204 3205 return false; 3206 } 3207 3208 typedef struct BdrvCoGetBlockStatusData { 3209 BlockDriverState *bs; 3210 BlockDriverState *base; 3211 int64_t sector_num; 3212 int nb_sectors; 3213 int *pnum; 3214 int64_t ret; 3215 bool done; 3216 } BdrvCoGetBlockStatusData; 3217 3218 /* 3219 * Returns true iff the specified sector is present in the disk image. Drivers 3220 * not implementing the functionality are assumed to not support backing files, 3221 * hence all their sectors are reported as allocated. 3222 * 3223 * If 'sector_num' is beyond the end of the disk image the return value is 0 3224 * and 'pnum' is set to 0. 3225 * 3226 * 'pnum' is set to the number of sectors (including and immediately following 3227 * the specified sector) that are known to be in the same 3228 * allocated/unallocated state. 3229 * 3230 * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes 3231 * beyond the end of the disk image it will be clamped. 3232 */ 3233 static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, 3234 int64_t sector_num, 3235 int nb_sectors, int *pnum) 3236 { 3237 int64_t length; 3238 int64_t n; 3239 int64_t ret, ret2; 3240 3241 length = bdrv_getlength(bs); 3242 if (length < 0) { 3243 return length; 3244 } 3245 3246 if (sector_num >= (length >> BDRV_SECTOR_BITS)) { 3247 *pnum = 0; 3248 return 0; 3249 } 3250 3251 n = bs->total_sectors - sector_num; 3252 if (n < nb_sectors) { 3253 nb_sectors = n; 3254 } 3255 3256 if (!bs->drv->bdrv_co_get_block_status) { 3257 *pnum = nb_sectors; 3258 ret = BDRV_BLOCK_DATA; 3259 if (bs->drv->protocol_name) { 3260 ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); 3261 } 3262 return ret; 3263 } 3264 3265 ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); 3266 if (ret < 0) { 3267 *pnum = 0; 3268 return ret; 3269 } 3270 3271 if (ret & BDRV_BLOCK_RAW) { 3272 assert(ret & BDRV_BLOCK_OFFSET_VALID); 3273 return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3274 *pnum, pnum); 3275 } 3276 3277 if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { 3278 if (bdrv_unallocated_blocks_are_zero(bs)) { 3279 ret |= BDRV_BLOCK_ZERO; 3280 } else if (bs->backing_hd) { 3281 BlockDriverState *bs2 = bs->backing_hd; 3282 int64_t length2 = bdrv_getlength(bs2); 3283 if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) { 3284 ret |= BDRV_BLOCK_ZERO; 3285 } 3286 } 3287 } 3288 3289 if (bs->file && 3290 (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && 3291 (ret & BDRV_BLOCK_OFFSET_VALID)) { 3292 ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3293 *pnum, pnum); 3294 if (ret2 >= 0) { 3295 /* Ignore errors. This is just providing extra information, it 3296 * is useful but not necessary. 3297 */ 3298 ret |= (ret2 & BDRV_BLOCK_ZERO); 3299 } 3300 } 3301 3302 return ret; 3303 } 3304 3305 /* Coroutine wrapper for bdrv_get_block_status() */ 3306 static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque) 3307 { 3308 BdrvCoGetBlockStatusData *data = opaque; 3309 BlockDriverState *bs = data->bs; 3310 3311 data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors, 3312 data->pnum); 3313 data->done = true; 3314 } 3315 3316 /* 3317 * Synchronous wrapper around bdrv_co_get_block_status(). 3318 * 3319 * See bdrv_co_get_block_status() for details. 3320 */ 3321 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, 3322 int nb_sectors, int *pnum) 3323 { 3324 Coroutine *co; 3325 BdrvCoGetBlockStatusData data = { 3326 .bs = bs, 3327 .sector_num = sector_num, 3328 .nb_sectors = nb_sectors, 3329 .pnum = pnum, 3330 .done = false, 3331 }; 3332 3333 if (qemu_in_coroutine()) { 3334 /* Fast-path if already in coroutine context */ 3335 bdrv_get_block_status_co_entry(&data); 3336 } else { 3337 co = qemu_coroutine_create(bdrv_get_block_status_co_entry); 3338 qemu_coroutine_enter(co, &data); 3339 while (!data.done) { 3340 qemu_aio_wait(); 3341 } 3342 } 3343 return data.ret; 3344 } 3345 3346 int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, 3347 int nb_sectors, int *pnum) 3348 { 3349 int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); 3350 if (ret < 0) { 3351 return ret; 3352 } 3353 return 3354 (ret & BDRV_BLOCK_DATA) || 3355 ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); 3356 } 3357 3358 /* 3359 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] 3360 * 3361 * Return true if the given sector is allocated in any image between 3362 * BASE and TOP (inclusive). BASE can be NULL to check if the given 3363 * sector is allocated in any image of the chain. Return false otherwise. 3364 * 3365 * 'pnum' is set to the number of sectors (including and immediately following 3366 * the specified sector) that are known to be in the same 3367 * allocated/unallocated state. 3368 * 3369 */ 3370 int bdrv_is_allocated_above(BlockDriverState *top, 3371 BlockDriverState *base, 3372 int64_t sector_num, 3373 int nb_sectors, int *pnum) 3374 { 3375 BlockDriverState *intermediate; 3376 int ret, n = nb_sectors; 3377 3378 intermediate = top; 3379 while (intermediate && intermediate != base) { 3380 int pnum_inter; 3381 ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors, 3382 &pnum_inter); 3383 if (ret < 0) { 3384 return ret; 3385 } else if (ret) { 3386 *pnum = pnum_inter; 3387 return 1; 3388 } 3389 3390 /* 3391 * [sector_num, nb_sectors] is unallocated on top but intermediate 3392 * might have 3393 * 3394 * [sector_num+x, nr_sectors] allocated. 3395 */ 3396 if (n > pnum_inter && 3397 (intermediate == top || 3398 sector_num + pnum_inter < intermediate->total_sectors)) { 3399 n = pnum_inter; 3400 } 3401 3402 intermediate = intermediate->backing_hd; 3403 } 3404 3405 *pnum = n; 3406 return 0; 3407 } 3408 3409 const char *bdrv_get_encrypted_filename(BlockDriverState *bs) 3410 { 3411 if (bs->backing_hd && bs->backing_hd->encrypted) 3412 return bs->backing_file; 3413 else if (bs->encrypted) 3414 return bs->filename; 3415 else 3416 return NULL; 3417 } 3418 3419 void bdrv_get_backing_filename(BlockDriverState *bs, 3420 char *filename, int filename_size) 3421 { 3422 pstrcpy(filename, filename_size, bs->backing_file); 3423 } 3424 3425 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num, 3426 const uint8_t *buf, int nb_sectors) 3427 { 3428 BlockDriver *drv = bs->drv; 3429 if (!drv) 3430 return -ENOMEDIUM; 3431 if (!drv->bdrv_write_compressed) 3432 return -ENOTSUP; 3433 if (bdrv_check_request(bs, sector_num, nb_sectors)) 3434 return -EIO; 3435 3436 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 3437 3438 return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors); 3439 } 3440 3441 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3442 { 3443 BlockDriver *drv = bs->drv; 3444 if (!drv) 3445 return -ENOMEDIUM; 3446 if (!drv->bdrv_get_info) 3447 return -ENOTSUP; 3448 memset(bdi, 0, sizeof(*bdi)); 3449 return drv->bdrv_get_info(bs, bdi); 3450 } 3451 3452 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) 3453 { 3454 BlockDriver *drv = bs->drv; 3455 if (drv && drv->bdrv_get_specific_info) { 3456 return drv->bdrv_get_specific_info(bs); 3457 } 3458 return NULL; 3459 } 3460 3461 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 3462 int64_t pos, int size) 3463 { 3464 QEMUIOVector qiov; 3465 struct iovec iov = { 3466 .iov_base = (void *) buf, 3467 .iov_len = size, 3468 }; 3469 3470 qemu_iovec_init_external(&qiov, &iov, 1); 3471 return bdrv_writev_vmstate(bs, &qiov, pos); 3472 } 3473 3474 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) 3475 { 3476 BlockDriver *drv = bs->drv; 3477 3478 if (!drv) { 3479 return -ENOMEDIUM; 3480 } else if (drv->bdrv_save_vmstate) { 3481 return drv->bdrv_save_vmstate(bs, qiov, pos); 3482 } else if (bs->file) { 3483 return bdrv_writev_vmstate(bs->file, qiov, pos); 3484 } 3485 3486 return -ENOTSUP; 3487 } 3488 3489 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 3490 int64_t pos, int size) 3491 { 3492 BlockDriver *drv = bs->drv; 3493 if (!drv) 3494 return -ENOMEDIUM; 3495 if (drv->bdrv_load_vmstate) 3496 return drv->bdrv_load_vmstate(bs, buf, pos, size); 3497 if (bs->file) 3498 return bdrv_load_vmstate(bs->file, buf, pos, size); 3499 return -ENOTSUP; 3500 } 3501 3502 void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event) 3503 { 3504 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { 3505 return; 3506 } 3507 3508 bs->drv->bdrv_debug_event(bs, event); 3509 } 3510 3511 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, 3512 const char *tag) 3513 { 3514 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { 3515 bs = bs->file; 3516 } 3517 3518 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { 3519 return bs->drv->bdrv_debug_breakpoint(bs, event, tag); 3520 } 3521 3522 return -ENOTSUP; 3523 } 3524 3525 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) 3526 { 3527 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { 3528 bs = bs->file; 3529 } 3530 3531 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { 3532 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); 3533 } 3534 3535 return -ENOTSUP; 3536 } 3537 3538 int bdrv_debug_resume(BlockDriverState *bs, const char *tag) 3539 { 3540 while (bs && bs->drv && !bs->drv->bdrv_debug_resume) { 3541 bs = bs->file; 3542 } 3543 3544 if (bs && bs->drv && bs->drv->bdrv_debug_resume) { 3545 return bs->drv->bdrv_debug_resume(bs, tag); 3546 } 3547 3548 return -ENOTSUP; 3549 } 3550 3551 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) 3552 { 3553 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { 3554 bs = bs->file; 3555 } 3556 3557 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { 3558 return bs->drv->bdrv_debug_is_suspended(bs, tag); 3559 } 3560 3561 return false; 3562 } 3563 3564 int bdrv_is_snapshot(BlockDriverState *bs) 3565 { 3566 return !!(bs->open_flags & BDRV_O_SNAPSHOT); 3567 } 3568 3569 /* backing_file can either be relative, or absolute, or a protocol. If it is 3570 * relative, it must be relative to the chain. So, passing in bs->filename 3571 * from a BDS as backing_file should not be done, as that may be relative to 3572 * the CWD rather than the chain. */ 3573 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 3574 const char *backing_file) 3575 { 3576 char *filename_full = NULL; 3577 char *backing_file_full = NULL; 3578 char *filename_tmp = NULL; 3579 int is_protocol = 0; 3580 BlockDriverState *curr_bs = NULL; 3581 BlockDriverState *retval = NULL; 3582 3583 if (!bs || !bs->drv || !backing_file) { 3584 return NULL; 3585 } 3586 3587 filename_full = g_malloc(PATH_MAX); 3588 backing_file_full = g_malloc(PATH_MAX); 3589 filename_tmp = g_malloc(PATH_MAX); 3590 3591 is_protocol = path_has_protocol(backing_file); 3592 3593 for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) { 3594 3595 /* If either of the filename paths is actually a protocol, then 3596 * compare unmodified paths; otherwise make paths relative */ 3597 if (is_protocol || path_has_protocol(curr_bs->backing_file)) { 3598 if (strcmp(backing_file, curr_bs->backing_file) == 0) { 3599 retval = curr_bs->backing_hd; 3600 break; 3601 } 3602 } else { 3603 /* If not an absolute filename path, make it relative to the current 3604 * image's filename path */ 3605 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3606 backing_file); 3607 3608 /* We are going to compare absolute pathnames */ 3609 if (!realpath(filename_tmp, filename_full)) { 3610 continue; 3611 } 3612 3613 /* We need to make sure the backing filename we are comparing against 3614 * is relative to the current image filename (or absolute) */ 3615 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3616 curr_bs->backing_file); 3617 3618 if (!realpath(filename_tmp, backing_file_full)) { 3619 continue; 3620 } 3621 3622 if (strcmp(backing_file_full, filename_full) == 0) { 3623 retval = curr_bs->backing_hd; 3624 break; 3625 } 3626 } 3627 } 3628 3629 g_free(filename_full); 3630 g_free(backing_file_full); 3631 g_free(filename_tmp); 3632 return retval; 3633 } 3634 3635 int bdrv_get_backing_file_depth(BlockDriverState *bs) 3636 { 3637 if (!bs->drv) { 3638 return 0; 3639 } 3640 3641 if (!bs->backing_hd) { 3642 return 0; 3643 } 3644 3645 return 1 + bdrv_get_backing_file_depth(bs->backing_hd); 3646 } 3647 3648 BlockDriverState *bdrv_find_base(BlockDriverState *bs) 3649 { 3650 BlockDriverState *curr_bs = NULL; 3651 3652 if (!bs) { 3653 return NULL; 3654 } 3655 3656 curr_bs = bs; 3657 3658 while (curr_bs->backing_hd) { 3659 curr_bs = curr_bs->backing_hd; 3660 } 3661 return curr_bs; 3662 } 3663 3664 /**************************************************************/ 3665 /* async I/Os */ 3666 3667 BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, 3668 QEMUIOVector *qiov, int nb_sectors, 3669 BlockDriverCompletionFunc *cb, void *opaque) 3670 { 3671 trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); 3672 3673 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 3674 cb, opaque, false); 3675 } 3676 3677 BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, 3678 QEMUIOVector *qiov, int nb_sectors, 3679 BlockDriverCompletionFunc *cb, void *opaque) 3680 { 3681 trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); 3682 3683 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 3684 cb, opaque, true); 3685 } 3686 3687 BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, 3688 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags, 3689 BlockDriverCompletionFunc *cb, void *opaque) 3690 { 3691 trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque); 3692 3693 return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors, 3694 BDRV_REQ_ZERO_WRITE | flags, 3695 cb, opaque, true); 3696 } 3697 3698 3699 typedef struct MultiwriteCB { 3700 int error; 3701 int num_requests; 3702 int num_callbacks; 3703 struct { 3704 BlockDriverCompletionFunc *cb; 3705 void *opaque; 3706 QEMUIOVector *free_qiov; 3707 } callbacks[]; 3708 } MultiwriteCB; 3709 3710 static void multiwrite_user_cb(MultiwriteCB *mcb) 3711 { 3712 int i; 3713 3714 for (i = 0; i < mcb->num_callbacks; i++) { 3715 mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error); 3716 if (mcb->callbacks[i].free_qiov) { 3717 qemu_iovec_destroy(mcb->callbacks[i].free_qiov); 3718 } 3719 g_free(mcb->callbacks[i].free_qiov); 3720 } 3721 } 3722 3723 static void multiwrite_cb(void *opaque, int ret) 3724 { 3725 MultiwriteCB *mcb = opaque; 3726 3727 trace_multiwrite_cb(mcb, ret); 3728 3729 if (ret < 0 && !mcb->error) { 3730 mcb->error = ret; 3731 } 3732 3733 mcb->num_requests--; 3734 if (mcb->num_requests == 0) { 3735 multiwrite_user_cb(mcb); 3736 g_free(mcb); 3737 } 3738 } 3739 3740 static int multiwrite_req_compare(const void *a, const void *b) 3741 { 3742 const BlockRequest *req1 = a, *req2 = b; 3743 3744 /* 3745 * Note that we can't simply subtract req2->sector from req1->sector 3746 * here as that could overflow the return value. 3747 */ 3748 if (req1->sector > req2->sector) { 3749 return 1; 3750 } else if (req1->sector < req2->sector) { 3751 return -1; 3752 } else { 3753 return 0; 3754 } 3755 } 3756 3757 /* 3758 * Takes a bunch of requests and tries to merge them. Returns the number of 3759 * requests that remain after merging. 3760 */ 3761 static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, 3762 int num_reqs, MultiwriteCB *mcb) 3763 { 3764 int i, outidx; 3765 3766 // Sort requests by start sector 3767 qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare); 3768 3769 // Check if adjacent requests touch the same clusters. If so, combine them, 3770 // filling up gaps with zero sectors. 3771 outidx = 0; 3772 for (i = 1; i < num_reqs; i++) { 3773 int merge = 0; 3774 int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors; 3775 3776 // Handle exactly sequential writes and overlapping writes. 3777 if (reqs[i].sector <= oldreq_last) { 3778 merge = 1; 3779 } 3780 3781 if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { 3782 merge = 0; 3783 } 3784 3785 if (merge) { 3786 size_t size; 3787 QEMUIOVector *qiov = g_malloc0(sizeof(*qiov)); 3788 qemu_iovec_init(qiov, 3789 reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1); 3790 3791 // Add the first request to the merged one. If the requests are 3792 // overlapping, drop the last sectors of the first request. 3793 size = (reqs[i].sector - reqs[outidx].sector) << 9; 3794 qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size); 3795 3796 // We should need to add any zeros between the two requests 3797 assert (reqs[i].sector <= oldreq_last); 3798 3799 // Add the second request 3800 qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size); 3801 3802 reqs[outidx].nb_sectors = qiov->size >> 9; 3803 reqs[outidx].qiov = qiov; 3804 3805 mcb->callbacks[i].free_qiov = reqs[outidx].qiov; 3806 } else { 3807 outidx++; 3808 reqs[outidx].sector = reqs[i].sector; 3809 reqs[outidx].nb_sectors = reqs[i].nb_sectors; 3810 reqs[outidx].qiov = reqs[i].qiov; 3811 } 3812 } 3813 3814 return outidx + 1; 3815 } 3816 3817 /* 3818 * Submit multiple AIO write requests at once. 3819 * 3820 * On success, the function returns 0 and all requests in the reqs array have 3821 * been submitted. In error case this function returns -1, and any of the 3822 * requests may or may not be submitted yet. In particular, this means that the 3823 * callback will be called for some of the requests, for others it won't. The 3824 * caller must check the error field of the BlockRequest to wait for the right 3825 * callbacks (if error != 0, no callback will be called). 3826 * 3827 * The implementation may modify the contents of the reqs array, e.g. to merge 3828 * requests. However, the fields opaque and error are left unmodified as they 3829 * are used to signal failure for a single request to the caller. 3830 */ 3831 int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) 3832 { 3833 MultiwriteCB *mcb; 3834 int i; 3835 3836 /* don't submit writes if we don't have a medium */ 3837 if (bs->drv == NULL) { 3838 for (i = 0; i < num_reqs; i++) { 3839 reqs[i].error = -ENOMEDIUM; 3840 } 3841 return -1; 3842 } 3843 3844 if (num_reqs == 0) { 3845 return 0; 3846 } 3847 3848 // Create MultiwriteCB structure 3849 mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks)); 3850 mcb->num_requests = 0; 3851 mcb->num_callbacks = num_reqs; 3852 3853 for (i = 0; i < num_reqs; i++) { 3854 mcb->callbacks[i].cb = reqs[i].cb; 3855 mcb->callbacks[i].opaque = reqs[i].opaque; 3856 } 3857 3858 // Check for mergable requests 3859 num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb); 3860 3861 trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs); 3862 3863 /* Run the aio requests. */ 3864 mcb->num_requests = num_reqs; 3865 for (i = 0; i < num_reqs; i++) { 3866 bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov, 3867 reqs[i].nb_sectors, reqs[i].flags, 3868 multiwrite_cb, mcb, 3869 true); 3870 } 3871 3872 return 0; 3873 } 3874 3875 void bdrv_aio_cancel(BlockDriverAIOCB *acb) 3876 { 3877 acb->aiocb_info->cancel(acb); 3878 } 3879 3880 /**************************************************************/ 3881 /* async block device emulation */ 3882 3883 typedef struct BlockDriverAIOCBSync { 3884 BlockDriverAIOCB common; 3885 QEMUBH *bh; 3886 int ret; 3887 /* vector translation state */ 3888 QEMUIOVector *qiov; 3889 uint8_t *bounce; 3890 int is_write; 3891 } BlockDriverAIOCBSync; 3892 3893 static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb) 3894 { 3895 BlockDriverAIOCBSync *acb = 3896 container_of(blockacb, BlockDriverAIOCBSync, common); 3897 qemu_bh_delete(acb->bh); 3898 acb->bh = NULL; 3899 qemu_aio_release(acb); 3900 } 3901 3902 static const AIOCBInfo bdrv_em_aiocb_info = { 3903 .aiocb_size = sizeof(BlockDriverAIOCBSync), 3904 .cancel = bdrv_aio_cancel_em, 3905 }; 3906 3907 static void bdrv_aio_bh_cb(void *opaque) 3908 { 3909 BlockDriverAIOCBSync *acb = opaque; 3910 3911 if (!acb->is_write) 3912 qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size); 3913 qemu_vfree(acb->bounce); 3914 acb->common.cb(acb->common.opaque, acb->ret); 3915 qemu_bh_delete(acb->bh); 3916 acb->bh = NULL; 3917 qemu_aio_release(acb); 3918 } 3919 3920 static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs, 3921 int64_t sector_num, 3922 QEMUIOVector *qiov, 3923 int nb_sectors, 3924 BlockDriverCompletionFunc *cb, 3925 void *opaque, 3926 int is_write) 3927 3928 { 3929 BlockDriverAIOCBSync *acb; 3930 3931 acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque); 3932 acb->is_write = is_write; 3933 acb->qiov = qiov; 3934 acb->bounce = qemu_blockalign(bs, qiov->size); 3935 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb); 3936 3937 if (is_write) { 3938 qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); 3939 acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors); 3940 } else { 3941 acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors); 3942 } 3943 3944 qemu_bh_schedule(acb->bh); 3945 3946 return &acb->common; 3947 } 3948 3949 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, 3950 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 3951 BlockDriverCompletionFunc *cb, void *opaque) 3952 { 3953 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 3954 } 3955 3956 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, 3957 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 3958 BlockDriverCompletionFunc *cb, void *opaque) 3959 { 3960 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); 3961 } 3962 3963 3964 typedef struct BlockDriverAIOCBCoroutine { 3965 BlockDriverAIOCB common; 3966 BlockRequest req; 3967 bool is_write; 3968 bool *done; 3969 QEMUBH* bh; 3970 } BlockDriverAIOCBCoroutine; 3971 3972 static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb) 3973 { 3974 BlockDriverAIOCBCoroutine *acb = 3975 container_of(blockacb, BlockDriverAIOCBCoroutine, common); 3976 bool done = false; 3977 3978 acb->done = &done; 3979 while (!done) { 3980 qemu_aio_wait(); 3981 } 3982 } 3983 3984 static const AIOCBInfo bdrv_em_co_aiocb_info = { 3985 .aiocb_size = sizeof(BlockDriverAIOCBCoroutine), 3986 .cancel = bdrv_aio_co_cancel_em, 3987 }; 3988 3989 static void bdrv_co_em_bh(void *opaque) 3990 { 3991 BlockDriverAIOCBCoroutine *acb = opaque; 3992 3993 acb->common.cb(acb->common.opaque, acb->req.error); 3994 3995 if (acb->done) { 3996 *acb->done = true; 3997 } 3998 3999 qemu_bh_delete(acb->bh); 4000 qemu_aio_release(acb); 4001 } 4002 4003 /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ 4004 static void coroutine_fn bdrv_co_do_rw(void *opaque) 4005 { 4006 BlockDriverAIOCBCoroutine *acb = opaque; 4007 BlockDriverState *bs = acb->common.bs; 4008 4009 if (!acb->is_write) { 4010 acb->req.error = bdrv_co_do_readv(bs, acb->req.sector, 4011 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4012 } else { 4013 acb->req.error = bdrv_co_do_writev(bs, acb->req.sector, 4014 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4015 } 4016 4017 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4018 qemu_bh_schedule(acb->bh); 4019 } 4020 4021 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, 4022 int64_t sector_num, 4023 QEMUIOVector *qiov, 4024 int nb_sectors, 4025 BdrvRequestFlags flags, 4026 BlockDriverCompletionFunc *cb, 4027 void *opaque, 4028 bool is_write) 4029 { 4030 Coroutine *co; 4031 BlockDriverAIOCBCoroutine *acb; 4032 4033 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4034 acb->req.sector = sector_num; 4035 acb->req.nb_sectors = nb_sectors; 4036 acb->req.qiov = qiov; 4037 acb->req.flags = flags; 4038 acb->is_write = is_write; 4039 acb->done = NULL; 4040 4041 co = qemu_coroutine_create(bdrv_co_do_rw); 4042 qemu_coroutine_enter(co, acb); 4043 4044 return &acb->common; 4045 } 4046 4047 static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque) 4048 { 4049 BlockDriverAIOCBCoroutine *acb = opaque; 4050 BlockDriverState *bs = acb->common.bs; 4051 4052 acb->req.error = bdrv_co_flush(bs); 4053 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4054 qemu_bh_schedule(acb->bh); 4055 } 4056 4057 BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, 4058 BlockDriverCompletionFunc *cb, void *opaque) 4059 { 4060 trace_bdrv_aio_flush(bs, opaque); 4061 4062 Coroutine *co; 4063 BlockDriverAIOCBCoroutine *acb; 4064 4065 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4066 acb->done = NULL; 4067 4068 co = qemu_coroutine_create(bdrv_aio_flush_co_entry); 4069 qemu_coroutine_enter(co, acb); 4070 4071 return &acb->common; 4072 } 4073 4074 static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque) 4075 { 4076 BlockDriverAIOCBCoroutine *acb = opaque; 4077 BlockDriverState *bs = acb->common.bs; 4078 4079 acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors); 4080 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4081 qemu_bh_schedule(acb->bh); 4082 } 4083 4084 BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs, 4085 int64_t sector_num, int nb_sectors, 4086 BlockDriverCompletionFunc *cb, void *opaque) 4087 { 4088 Coroutine *co; 4089 BlockDriverAIOCBCoroutine *acb; 4090 4091 trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque); 4092 4093 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4094 acb->req.sector = sector_num; 4095 acb->req.nb_sectors = nb_sectors; 4096 acb->done = NULL; 4097 co = qemu_coroutine_create(bdrv_aio_discard_co_entry); 4098 qemu_coroutine_enter(co, acb); 4099 4100 return &acb->common; 4101 } 4102 4103 void bdrv_init(void) 4104 { 4105 module_call_init(MODULE_INIT_BLOCK); 4106 } 4107 4108 void bdrv_init_with_whitelist(void) 4109 { 4110 use_bdrv_whitelist = 1; 4111 bdrv_init(); 4112 } 4113 4114 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, 4115 BlockDriverCompletionFunc *cb, void *opaque) 4116 { 4117 BlockDriverAIOCB *acb; 4118 4119 acb = g_slice_alloc(aiocb_info->aiocb_size); 4120 acb->aiocb_info = aiocb_info; 4121 acb->bs = bs; 4122 acb->cb = cb; 4123 acb->opaque = opaque; 4124 return acb; 4125 } 4126 4127 void qemu_aio_release(void *p) 4128 { 4129 BlockDriverAIOCB *acb = p; 4130 g_slice_free1(acb->aiocb_info->aiocb_size, acb); 4131 } 4132 4133 /**************************************************************/ 4134 /* Coroutine block device emulation */ 4135 4136 typedef struct CoroutineIOCompletion { 4137 Coroutine *coroutine; 4138 int ret; 4139 } CoroutineIOCompletion; 4140 4141 static void bdrv_co_io_em_complete(void *opaque, int ret) 4142 { 4143 CoroutineIOCompletion *co = opaque; 4144 4145 co->ret = ret; 4146 qemu_coroutine_enter(co->coroutine, NULL); 4147 } 4148 4149 static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num, 4150 int nb_sectors, QEMUIOVector *iov, 4151 bool is_write) 4152 { 4153 CoroutineIOCompletion co = { 4154 .coroutine = qemu_coroutine_self(), 4155 }; 4156 BlockDriverAIOCB *acb; 4157 4158 if (is_write) { 4159 acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors, 4160 bdrv_co_io_em_complete, &co); 4161 } else { 4162 acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors, 4163 bdrv_co_io_em_complete, &co); 4164 } 4165 4166 trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb); 4167 if (!acb) { 4168 return -EIO; 4169 } 4170 qemu_coroutine_yield(); 4171 4172 return co.ret; 4173 } 4174 4175 static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, 4176 int64_t sector_num, int nb_sectors, 4177 QEMUIOVector *iov) 4178 { 4179 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false); 4180 } 4181 4182 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, 4183 int64_t sector_num, int nb_sectors, 4184 QEMUIOVector *iov) 4185 { 4186 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true); 4187 } 4188 4189 static void coroutine_fn bdrv_flush_co_entry(void *opaque) 4190 { 4191 RwCo *rwco = opaque; 4192 4193 rwco->ret = bdrv_co_flush(rwco->bs); 4194 } 4195 4196 int coroutine_fn bdrv_co_flush(BlockDriverState *bs) 4197 { 4198 int ret; 4199 4200 if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { 4201 return 0; 4202 } 4203 4204 /* Write back cached data to the OS even with cache=unsafe */ 4205 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); 4206 if (bs->drv->bdrv_co_flush_to_os) { 4207 ret = bs->drv->bdrv_co_flush_to_os(bs); 4208 if (ret < 0) { 4209 return ret; 4210 } 4211 } 4212 4213 /* But don't actually force it to the disk with cache=unsafe */ 4214 if (bs->open_flags & BDRV_O_NO_FLUSH) { 4215 goto flush_parent; 4216 } 4217 4218 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); 4219 if (bs->drv->bdrv_co_flush_to_disk) { 4220 ret = bs->drv->bdrv_co_flush_to_disk(bs); 4221 } else if (bs->drv->bdrv_aio_flush) { 4222 BlockDriverAIOCB *acb; 4223 CoroutineIOCompletion co = { 4224 .coroutine = qemu_coroutine_self(), 4225 }; 4226 4227 acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); 4228 if (acb == NULL) { 4229 ret = -EIO; 4230 } else { 4231 qemu_coroutine_yield(); 4232 ret = co.ret; 4233 } 4234 } else { 4235 /* 4236 * Some block drivers always operate in either writethrough or unsafe 4237 * mode and don't support bdrv_flush therefore. Usually qemu doesn't 4238 * know how the server works (because the behaviour is hardcoded or 4239 * depends on server-side configuration), so we can't ensure that 4240 * everything is safe on disk. Returning an error doesn't work because 4241 * that would break guests even if the server operates in writethrough 4242 * mode. 4243 * 4244 * Let's hope the user knows what he's doing. 4245 */ 4246 ret = 0; 4247 } 4248 if (ret < 0) { 4249 return ret; 4250 } 4251 4252 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH 4253 * in the case of cache=unsafe, so there are no useless flushes. 4254 */ 4255 flush_parent: 4256 return bdrv_co_flush(bs->file); 4257 } 4258 4259 void bdrv_invalidate_cache(BlockDriverState *bs) 4260 { 4261 if (bs->drv && bs->drv->bdrv_invalidate_cache) { 4262 bs->drv->bdrv_invalidate_cache(bs); 4263 } 4264 } 4265 4266 void bdrv_invalidate_cache_all(void) 4267 { 4268 BlockDriverState *bs; 4269 4270 QTAILQ_FOREACH(bs, &bdrv_states, list) { 4271 bdrv_invalidate_cache(bs); 4272 } 4273 } 4274 4275 void bdrv_clear_incoming_migration_all(void) 4276 { 4277 BlockDriverState *bs; 4278 4279 QTAILQ_FOREACH(bs, &bdrv_states, list) { 4280 bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING); 4281 } 4282 } 4283 4284 int bdrv_flush(BlockDriverState *bs) 4285 { 4286 Coroutine *co; 4287 RwCo rwco = { 4288 .bs = bs, 4289 .ret = NOT_DONE, 4290 }; 4291 4292 if (qemu_in_coroutine()) { 4293 /* Fast-path if already in coroutine context */ 4294 bdrv_flush_co_entry(&rwco); 4295 } else { 4296 co = qemu_coroutine_create(bdrv_flush_co_entry); 4297 qemu_coroutine_enter(co, &rwco); 4298 while (rwco.ret == NOT_DONE) { 4299 qemu_aio_wait(); 4300 } 4301 } 4302 4303 return rwco.ret; 4304 } 4305 4306 static void coroutine_fn bdrv_discard_co_entry(void *opaque) 4307 { 4308 RwCo *rwco = opaque; 4309 4310 rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); 4311 } 4312 4313 /* if no limit is specified in the BlockLimits use a default 4314 * of 32768 512-byte sectors (16 MiB) per request. 4315 */ 4316 #define MAX_DISCARD_DEFAULT 32768 4317 4318 int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, 4319 int nb_sectors) 4320 { 4321 int max_discard; 4322 4323 if (!bs->drv) { 4324 return -ENOMEDIUM; 4325 } else if (bdrv_check_request(bs, sector_num, nb_sectors)) { 4326 return -EIO; 4327 } else if (bs->read_only) { 4328 return -EROFS; 4329 } 4330 4331 bdrv_reset_dirty(bs, sector_num, nb_sectors); 4332 4333 /* Do nothing if disabled. */ 4334 if (!(bs->open_flags & BDRV_O_UNMAP)) { 4335 return 0; 4336 } 4337 4338 if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) { 4339 return 0; 4340 } 4341 4342 max_discard = bs->bl.max_discard ? bs->bl.max_discard : MAX_DISCARD_DEFAULT; 4343 while (nb_sectors > 0) { 4344 int ret; 4345 int num = nb_sectors; 4346 4347 /* align request */ 4348 if (bs->bl.discard_alignment && 4349 num >= bs->bl.discard_alignment && 4350 sector_num % bs->bl.discard_alignment) { 4351 if (num > bs->bl.discard_alignment) { 4352 num = bs->bl.discard_alignment; 4353 } 4354 num -= sector_num % bs->bl.discard_alignment; 4355 } 4356 4357 /* limit request size */ 4358 if (num > max_discard) { 4359 num = max_discard; 4360 } 4361 4362 if (bs->drv->bdrv_co_discard) { 4363 ret = bs->drv->bdrv_co_discard(bs, sector_num, num); 4364 } else { 4365 BlockDriverAIOCB *acb; 4366 CoroutineIOCompletion co = { 4367 .coroutine = qemu_coroutine_self(), 4368 }; 4369 4370 acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, 4371 bdrv_co_io_em_complete, &co); 4372 if (acb == NULL) { 4373 return -EIO; 4374 } else { 4375 qemu_coroutine_yield(); 4376 ret = co.ret; 4377 } 4378 } 4379 if (ret) { 4380 return ret; 4381 } 4382 4383 sector_num += num; 4384 nb_sectors -= num; 4385 } 4386 return 0; 4387 } 4388 4389 int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) 4390 { 4391 Coroutine *co; 4392 RwCo rwco = { 4393 .bs = bs, 4394 .sector_num = sector_num, 4395 .nb_sectors = nb_sectors, 4396 .ret = NOT_DONE, 4397 }; 4398 4399 if (qemu_in_coroutine()) { 4400 /* Fast-path if already in coroutine context */ 4401 bdrv_discard_co_entry(&rwco); 4402 } else { 4403 co = qemu_coroutine_create(bdrv_discard_co_entry); 4404 qemu_coroutine_enter(co, &rwco); 4405 while (rwco.ret == NOT_DONE) { 4406 qemu_aio_wait(); 4407 } 4408 } 4409 4410 return rwco.ret; 4411 } 4412 4413 /**************************************************************/ 4414 /* removable device support */ 4415 4416 /** 4417 * Return TRUE if the media is present 4418 */ 4419 int bdrv_is_inserted(BlockDriverState *bs) 4420 { 4421 BlockDriver *drv = bs->drv; 4422 4423 if (!drv) 4424 return 0; 4425 if (!drv->bdrv_is_inserted) 4426 return 1; 4427 return drv->bdrv_is_inserted(bs); 4428 } 4429 4430 /** 4431 * Return whether the media changed since the last call to this 4432 * function, or -ENOTSUP if we don't know. Most drivers don't know. 4433 */ 4434 int bdrv_media_changed(BlockDriverState *bs) 4435 { 4436 BlockDriver *drv = bs->drv; 4437 4438 if (drv && drv->bdrv_media_changed) { 4439 return drv->bdrv_media_changed(bs); 4440 } 4441 return -ENOTSUP; 4442 } 4443 4444 /** 4445 * If eject_flag is TRUE, eject the media. Otherwise, close the tray 4446 */ 4447 void bdrv_eject(BlockDriverState *bs, bool eject_flag) 4448 { 4449 BlockDriver *drv = bs->drv; 4450 4451 if (drv && drv->bdrv_eject) { 4452 drv->bdrv_eject(bs, eject_flag); 4453 } 4454 4455 if (bs->device_name[0] != '\0') { 4456 bdrv_emit_qmp_eject_event(bs, eject_flag); 4457 } 4458 } 4459 4460 /** 4461 * Lock or unlock the media (if it is locked, the user won't be able 4462 * to eject it manually). 4463 */ 4464 void bdrv_lock_medium(BlockDriverState *bs, bool locked) 4465 { 4466 BlockDriver *drv = bs->drv; 4467 4468 trace_bdrv_lock_medium(bs, locked); 4469 4470 if (drv && drv->bdrv_lock_medium) { 4471 drv->bdrv_lock_medium(bs, locked); 4472 } 4473 } 4474 4475 /* needed for generic scsi interface */ 4476 4477 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf) 4478 { 4479 BlockDriver *drv = bs->drv; 4480 4481 if (drv && drv->bdrv_ioctl) 4482 return drv->bdrv_ioctl(bs, req, buf); 4483 return -ENOTSUP; 4484 } 4485 4486 BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, 4487 unsigned long int req, void *buf, 4488 BlockDriverCompletionFunc *cb, void *opaque) 4489 { 4490 BlockDriver *drv = bs->drv; 4491 4492 if (drv && drv->bdrv_aio_ioctl) 4493 return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque); 4494 return NULL; 4495 } 4496 4497 void bdrv_set_buffer_alignment(BlockDriverState *bs, int align) 4498 { 4499 bs->buffer_alignment = align; 4500 } 4501 4502 void *qemu_blockalign(BlockDriverState *bs, size_t size) 4503 { 4504 return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size); 4505 } 4506 4507 /* 4508 * Check if all memory in this vector is sector aligned. 4509 */ 4510 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) 4511 { 4512 int i; 4513 4514 for (i = 0; i < qiov->niov; i++) { 4515 if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) { 4516 return false; 4517 } 4518 } 4519 4520 return true; 4521 } 4522 4523 BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity) 4524 { 4525 int64_t bitmap_size; 4526 BdrvDirtyBitmap *bitmap; 4527 4528 assert((granularity & (granularity - 1)) == 0); 4529 4530 granularity >>= BDRV_SECTOR_BITS; 4531 assert(granularity); 4532 bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS); 4533 bitmap = g_malloc0(sizeof(BdrvDirtyBitmap)); 4534 bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1); 4535 QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list); 4536 return bitmap; 4537 } 4538 4539 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 4540 { 4541 BdrvDirtyBitmap *bm, *next; 4542 QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { 4543 if (bm == bitmap) { 4544 QLIST_REMOVE(bitmap, list); 4545 hbitmap_free(bitmap->bitmap); 4546 g_free(bitmap); 4547 return; 4548 } 4549 } 4550 } 4551 4552 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs) 4553 { 4554 BdrvDirtyBitmap *bm; 4555 BlockDirtyInfoList *list = NULL; 4556 BlockDirtyInfoList **plist = &list; 4557 4558 QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { 4559 BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo)); 4560 BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList)); 4561 info->count = bdrv_get_dirty_count(bs, bm); 4562 info->granularity = 4563 ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap)); 4564 entry->value = info; 4565 *plist = entry; 4566 plist = &entry->next; 4567 } 4568 4569 return list; 4570 } 4571 4572 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector) 4573 { 4574 if (bitmap) { 4575 return hbitmap_get(bitmap->bitmap, sector); 4576 } else { 4577 return 0; 4578 } 4579 } 4580 4581 void bdrv_dirty_iter_init(BlockDriverState *bs, 4582 BdrvDirtyBitmap *bitmap, HBitmapIter *hbi) 4583 { 4584 hbitmap_iter_init(hbi, bitmap->bitmap, 0); 4585 } 4586 4587 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, 4588 int nr_sectors) 4589 { 4590 BdrvDirtyBitmap *bitmap; 4591 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 4592 hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); 4593 } 4594 } 4595 4596 void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) 4597 { 4598 BdrvDirtyBitmap *bitmap; 4599 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 4600 hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); 4601 } 4602 } 4603 4604 int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 4605 { 4606 return hbitmap_count(bitmap->bitmap); 4607 } 4608 4609 /* Get a reference to bs */ 4610 void bdrv_ref(BlockDriverState *bs) 4611 { 4612 bs->refcnt++; 4613 } 4614 4615 /* Release a previously grabbed reference to bs. 4616 * If after releasing, reference count is zero, the BlockDriverState is 4617 * deleted. */ 4618 void bdrv_unref(BlockDriverState *bs) 4619 { 4620 assert(bs->refcnt > 0); 4621 if (--bs->refcnt == 0) { 4622 bdrv_delete(bs); 4623 } 4624 } 4625 4626 void bdrv_set_in_use(BlockDriverState *bs, int in_use) 4627 { 4628 assert(bs->in_use != in_use); 4629 bs->in_use = in_use; 4630 } 4631 4632 int bdrv_in_use(BlockDriverState *bs) 4633 { 4634 return bs->in_use; 4635 } 4636 4637 void bdrv_iostatus_enable(BlockDriverState *bs) 4638 { 4639 bs->iostatus_enabled = true; 4640 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 4641 } 4642 4643 /* The I/O status is only enabled if the drive explicitly 4644 * enables it _and_ the VM is configured to stop on errors */ 4645 bool bdrv_iostatus_is_enabled(const BlockDriverState *bs) 4646 { 4647 return (bs->iostatus_enabled && 4648 (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC || 4649 bs->on_write_error == BLOCKDEV_ON_ERROR_STOP || 4650 bs->on_read_error == BLOCKDEV_ON_ERROR_STOP)); 4651 } 4652 4653 void bdrv_iostatus_disable(BlockDriverState *bs) 4654 { 4655 bs->iostatus_enabled = false; 4656 } 4657 4658 void bdrv_iostatus_reset(BlockDriverState *bs) 4659 { 4660 if (bdrv_iostatus_is_enabled(bs)) { 4661 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 4662 if (bs->job) { 4663 block_job_iostatus_reset(bs->job); 4664 } 4665 } 4666 } 4667 4668 void bdrv_iostatus_set_err(BlockDriverState *bs, int error) 4669 { 4670 assert(bdrv_iostatus_is_enabled(bs)); 4671 if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 4672 bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : 4673 BLOCK_DEVICE_IO_STATUS_FAILED; 4674 } 4675 } 4676 4677 void 4678 bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes, 4679 enum BlockAcctType type) 4680 { 4681 assert(type < BDRV_MAX_IOTYPE); 4682 4683 cookie->bytes = bytes; 4684 cookie->start_time_ns = get_clock(); 4685 cookie->type = type; 4686 } 4687 4688 void 4689 bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie) 4690 { 4691 assert(cookie->type < BDRV_MAX_IOTYPE); 4692 4693 bs->nr_bytes[cookie->type] += cookie->bytes; 4694 bs->nr_ops[cookie->type]++; 4695 bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns; 4696 } 4697 4698 void bdrv_img_create(const char *filename, const char *fmt, 4699 const char *base_filename, const char *base_fmt, 4700 char *options, uint64_t img_size, int flags, 4701 Error **errp, bool quiet) 4702 { 4703 QEMUOptionParameter *param = NULL, *create_options = NULL; 4704 QEMUOptionParameter *backing_fmt, *backing_file, *size; 4705 BlockDriverState *bs = NULL; 4706 BlockDriver *drv, *proto_drv; 4707 BlockDriver *backing_drv = NULL; 4708 Error *local_err = NULL; 4709 int ret = 0; 4710 4711 /* Find driver and parse its options */ 4712 drv = bdrv_find_format(fmt); 4713 if (!drv) { 4714 error_setg(errp, "Unknown file format '%s'", fmt); 4715 return; 4716 } 4717 4718 proto_drv = bdrv_find_protocol(filename, true); 4719 if (!proto_drv) { 4720 error_setg(errp, "Unknown protocol '%s'", filename); 4721 return; 4722 } 4723 4724 create_options = append_option_parameters(create_options, 4725 drv->create_options); 4726 create_options = append_option_parameters(create_options, 4727 proto_drv->create_options); 4728 4729 /* Create parameter list with default values */ 4730 param = parse_option_parameters("", create_options, param); 4731 4732 set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size); 4733 4734 /* Parse -o options */ 4735 if (options) { 4736 param = parse_option_parameters(options, create_options, param); 4737 if (param == NULL) { 4738 error_setg(errp, "Invalid options for file format '%s'.", fmt); 4739 goto out; 4740 } 4741 } 4742 4743 if (base_filename) { 4744 if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE, 4745 base_filename)) { 4746 error_setg(errp, "Backing file not supported for file format '%s'", 4747 fmt); 4748 goto out; 4749 } 4750 } 4751 4752 if (base_fmt) { 4753 if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) { 4754 error_setg(errp, "Backing file format not supported for file " 4755 "format '%s'", fmt); 4756 goto out; 4757 } 4758 } 4759 4760 backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); 4761 if (backing_file && backing_file->value.s) { 4762 if (!strcmp(filename, backing_file->value.s)) { 4763 error_setg(errp, "Error: Trying to create an image with the " 4764 "same filename as the backing file"); 4765 goto out; 4766 } 4767 } 4768 4769 backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT); 4770 if (backing_fmt && backing_fmt->value.s) { 4771 backing_drv = bdrv_find_format(backing_fmt->value.s); 4772 if (!backing_drv) { 4773 error_setg(errp, "Unknown backing file format '%s'", 4774 backing_fmt->value.s); 4775 goto out; 4776 } 4777 } 4778 4779 // The size for the image must always be specified, with one exception: 4780 // If we are using a backing file, we can obtain the size from there 4781 size = get_option_parameter(param, BLOCK_OPT_SIZE); 4782 if (size && size->value.n == -1) { 4783 if (backing_file && backing_file->value.s) { 4784 uint64_t size; 4785 char buf[32]; 4786 int back_flags; 4787 4788 /* backing files always opened read-only */ 4789 back_flags = 4790 flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 4791 4792 bs = bdrv_new(""); 4793 4794 ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags, 4795 backing_drv, &local_err); 4796 if (ret < 0) { 4797 error_setg_errno(errp, -ret, "Could not open '%s': %s", 4798 backing_file->value.s, 4799 error_get_pretty(local_err)); 4800 error_free(local_err); 4801 local_err = NULL; 4802 goto out; 4803 } 4804 bdrv_get_geometry(bs, &size); 4805 size *= 512; 4806 4807 snprintf(buf, sizeof(buf), "%" PRId64, size); 4808 set_option_parameter(param, BLOCK_OPT_SIZE, buf); 4809 } else { 4810 error_setg(errp, "Image creation needs a size parameter"); 4811 goto out; 4812 } 4813 } 4814 4815 if (!quiet) { 4816 printf("Formatting '%s', fmt=%s ", filename, fmt); 4817 print_option_parameters(param); 4818 puts(""); 4819 } 4820 ret = bdrv_create(drv, filename, param, &local_err); 4821 if (ret == -EFBIG) { 4822 /* This is generally a better message than whatever the driver would 4823 * deliver (especially because of the cluster_size_hint), since that 4824 * is most probably not much different from "image too large". */ 4825 const char *cluster_size_hint = ""; 4826 if (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) { 4827 cluster_size_hint = " (try using a larger cluster size)"; 4828 } 4829 error_setg(errp, "The image size is too large for file format '%s'" 4830 "%s", fmt, cluster_size_hint); 4831 error_free(local_err); 4832 local_err = NULL; 4833 } 4834 4835 out: 4836 free_option_parameters(create_options); 4837 free_option_parameters(param); 4838 4839 if (bs) { 4840 bdrv_unref(bs); 4841 } 4842 if (error_is_set(&local_err)) { 4843 error_propagate(errp, local_err); 4844 } 4845 } 4846 4847 AioContext *bdrv_get_aio_context(BlockDriverState *bs) 4848 { 4849 /* Currently BlockDriverState always uses the main loop AioContext */ 4850 return qemu_get_aio_context(); 4851 } 4852 4853 void bdrv_add_before_write_notifier(BlockDriverState *bs, 4854 NotifierWithReturn *notifier) 4855 { 4856 notifier_with_return_list_add(&bs->before_write_notifiers, notifier); 4857 } 4858 4859 int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options) 4860 { 4861 if (bs->drv->bdrv_amend_options == NULL) { 4862 return -ENOTSUP; 4863 } 4864 return bs->drv->bdrv_amend_options(bs, options); 4865 } 4866 4867 ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs) 4868 { 4869 if (bs->drv->bdrv_check_ext_snapshot) { 4870 return bs->drv->bdrv_check_ext_snapshot(bs); 4871 } 4872 4873 if (bs->file && bs->file->drv && bs->file->drv->bdrv_check_ext_snapshot) { 4874 return bs->file->drv->bdrv_check_ext_snapshot(bs); 4875 } 4876 4877 /* external snapshots are allowed by default */ 4878 return EXT_SNAPSHOT_ALLOWED; 4879 } 4880 4881 ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs) 4882 { 4883 return EXT_SNAPSHOT_FORBIDDEN; 4884 } 4885