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 QTAILQ_FOREACH(bs, &bdrv_states, list) { 1561 bdrv_start_throttled_reqs(bs); 1562 } 1563 1564 busy = bdrv_requests_pending_all(); 1565 busy |= aio_poll(qemu_get_aio_context(), busy); 1566 } 1567 } 1568 1569 /* make a BlockDriverState anonymous by removing from bdrv_state list. 1570 Also, NULL terminate the device_name to prevent double remove */ 1571 void bdrv_make_anon(BlockDriverState *bs) 1572 { 1573 if (bs->device_name[0] != '\0') { 1574 QTAILQ_REMOVE(&bdrv_states, bs, list); 1575 } 1576 bs->device_name[0] = '\0'; 1577 } 1578 1579 static void bdrv_rebind(BlockDriverState *bs) 1580 { 1581 if (bs->drv && bs->drv->bdrv_rebind) { 1582 bs->drv->bdrv_rebind(bs); 1583 } 1584 } 1585 1586 static void bdrv_move_feature_fields(BlockDriverState *bs_dest, 1587 BlockDriverState *bs_src) 1588 { 1589 /* move some fields that need to stay attached to the device */ 1590 bs_dest->open_flags = bs_src->open_flags; 1591 1592 /* dev info */ 1593 bs_dest->dev_ops = bs_src->dev_ops; 1594 bs_dest->dev_opaque = bs_src->dev_opaque; 1595 bs_dest->dev = bs_src->dev; 1596 bs_dest->buffer_alignment = bs_src->buffer_alignment; 1597 bs_dest->copy_on_read = bs_src->copy_on_read; 1598 1599 bs_dest->enable_write_cache = bs_src->enable_write_cache; 1600 1601 /* i/o throttled req */ 1602 memcpy(&bs_dest->throttle_state, 1603 &bs_src->throttle_state, 1604 sizeof(ThrottleState)); 1605 bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; 1606 bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; 1607 bs_dest->io_limits_enabled = bs_src->io_limits_enabled; 1608 1609 /* r/w error */ 1610 bs_dest->on_read_error = bs_src->on_read_error; 1611 bs_dest->on_write_error = bs_src->on_write_error; 1612 1613 /* i/o status */ 1614 bs_dest->iostatus_enabled = bs_src->iostatus_enabled; 1615 bs_dest->iostatus = bs_src->iostatus; 1616 1617 /* dirty bitmap */ 1618 bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps; 1619 1620 /* reference count */ 1621 bs_dest->refcnt = bs_src->refcnt; 1622 1623 /* job */ 1624 bs_dest->in_use = bs_src->in_use; 1625 bs_dest->job = bs_src->job; 1626 1627 /* keep the same entry in bdrv_states */ 1628 pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name), 1629 bs_src->device_name); 1630 bs_dest->list = bs_src->list; 1631 } 1632 1633 /* 1634 * Swap bs contents for two image chains while they are live, 1635 * while keeping required fields on the BlockDriverState that is 1636 * actually attached to a device. 1637 * 1638 * This will modify the BlockDriverState fields, and swap contents 1639 * between bs_new and bs_old. Both bs_new and bs_old are modified. 1640 * 1641 * bs_new is required to be anonymous. 1642 * 1643 * This function does not create any image files. 1644 */ 1645 void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) 1646 { 1647 BlockDriverState tmp; 1648 1649 /* bs_new must be anonymous and shouldn't have anything fancy enabled */ 1650 assert(bs_new->device_name[0] == '\0'); 1651 assert(QLIST_EMPTY(&bs_new->dirty_bitmaps)); 1652 assert(bs_new->job == NULL); 1653 assert(bs_new->dev == NULL); 1654 assert(bs_new->in_use == 0); 1655 assert(bs_new->io_limits_enabled == false); 1656 assert(!throttle_have_timer(&bs_new->throttle_state)); 1657 1658 tmp = *bs_new; 1659 *bs_new = *bs_old; 1660 *bs_old = tmp; 1661 1662 /* there are some fields that should not be swapped, move them back */ 1663 bdrv_move_feature_fields(&tmp, bs_old); 1664 bdrv_move_feature_fields(bs_old, bs_new); 1665 bdrv_move_feature_fields(bs_new, &tmp); 1666 1667 /* bs_new shouldn't be in bdrv_states even after the swap! */ 1668 assert(bs_new->device_name[0] == '\0'); 1669 1670 /* Check a few fields that should remain attached to the device */ 1671 assert(bs_new->dev == NULL); 1672 assert(bs_new->job == NULL); 1673 assert(bs_new->in_use == 0); 1674 assert(bs_new->io_limits_enabled == false); 1675 assert(!throttle_have_timer(&bs_new->throttle_state)); 1676 1677 bdrv_rebind(bs_new); 1678 bdrv_rebind(bs_old); 1679 } 1680 1681 /* 1682 * Add new bs contents at the top of an image chain while the chain is 1683 * live, while keeping required fields on the top layer. 1684 * 1685 * This will modify the BlockDriverState fields, and swap contents 1686 * between bs_new and bs_top. Both bs_new and bs_top are modified. 1687 * 1688 * bs_new is required to be anonymous. 1689 * 1690 * This function does not create any image files. 1691 */ 1692 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) 1693 { 1694 bdrv_swap(bs_new, bs_top); 1695 1696 /* The contents of 'tmp' will become bs_top, as we are 1697 * swapping bs_new and bs_top contents. */ 1698 bs_top->backing_hd = bs_new; 1699 bs_top->open_flags &= ~BDRV_O_NO_BACKING; 1700 pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file), 1701 bs_new->filename); 1702 pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format), 1703 bs_new->drv ? bs_new->drv->format_name : ""); 1704 } 1705 1706 static void bdrv_delete(BlockDriverState *bs) 1707 { 1708 assert(!bs->dev); 1709 assert(!bs->job); 1710 assert(!bs->in_use); 1711 assert(!bs->refcnt); 1712 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 1713 1714 bdrv_close(bs); 1715 1716 /* remove from list, if necessary */ 1717 bdrv_make_anon(bs); 1718 1719 g_free(bs); 1720 } 1721 1722 int bdrv_attach_dev(BlockDriverState *bs, void *dev) 1723 /* TODO change to DeviceState *dev when all users are qdevified */ 1724 { 1725 if (bs->dev) { 1726 return -EBUSY; 1727 } 1728 bs->dev = dev; 1729 bdrv_iostatus_reset(bs); 1730 return 0; 1731 } 1732 1733 /* TODO qdevified devices don't use this, remove when devices are qdevified */ 1734 void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev) 1735 { 1736 if (bdrv_attach_dev(bs, dev) < 0) { 1737 abort(); 1738 } 1739 } 1740 1741 void bdrv_detach_dev(BlockDriverState *bs, void *dev) 1742 /* TODO change to DeviceState *dev when all users are qdevified */ 1743 { 1744 assert(bs->dev == dev); 1745 bs->dev = NULL; 1746 bs->dev_ops = NULL; 1747 bs->dev_opaque = NULL; 1748 bs->buffer_alignment = 512; 1749 } 1750 1751 /* TODO change to return DeviceState * when all users are qdevified */ 1752 void *bdrv_get_attached_dev(BlockDriverState *bs) 1753 { 1754 return bs->dev; 1755 } 1756 1757 void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops, 1758 void *opaque) 1759 { 1760 bs->dev_ops = ops; 1761 bs->dev_opaque = opaque; 1762 } 1763 1764 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv, 1765 enum MonitorEvent ev, 1766 BlockErrorAction action, bool is_read) 1767 { 1768 QObject *data; 1769 const char *action_str; 1770 1771 switch (action) { 1772 case BDRV_ACTION_REPORT: 1773 action_str = "report"; 1774 break; 1775 case BDRV_ACTION_IGNORE: 1776 action_str = "ignore"; 1777 break; 1778 case BDRV_ACTION_STOP: 1779 action_str = "stop"; 1780 break; 1781 default: 1782 abort(); 1783 } 1784 1785 data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }", 1786 bdrv->device_name, 1787 action_str, 1788 is_read ? "read" : "write"); 1789 monitor_protocol_event(ev, data); 1790 1791 qobject_decref(data); 1792 } 1793 1794 static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected) 1795 { 1796 QObject *data; 1797 1798 data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }", 1799 bdrv_get_device_name(bs), ejected); 1800 monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data); 1801 1802 qobject_decref(data); 1803 } 1804 1805 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load) 1806 { 1807 if (bs->dev_ops && bs->dev_ops->change_media_cb) { 1808 bool tray_was_closed = !bdrv_dev_is_tray_open(bs); 1809 bs->dev_ops->change_media_cb(bs->dev_opaque, load); 1810 if (tray_was_closed) { 1811 /* tray open */ 1812 bdrv_emit_qmp_eject_event(bs, true); 1813 } 1814 if (load) { 1815 /* tray close */ 1816 bdrv_emit_qmp_eject_event(bs, false); 1817 } 1818 } 1819 } 1820 1821 bool bdrv_dev_has_removable_media(BlockDriverState *bs) 1822 { 1823 return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb); 1824 } 1825 1826 void bdrv_dev_eject_request(BlockDriverState *bs, bool force) 1827 { 1828 if (bs->dev_ops && bs->dev_ops->eject_request_cb) { 1829 bs->dev_ops->eject_request_cb(bs->dev_opaque, force); 1830 } 1831 } 1832 1833 bool bdrv_dev_is_tray_open(BlockDriverState *bs) 1834 { 1835 if (bs->dev_ops && bs->dev_ops->is_tray_open) { 1836 return bs->dev_ops->is_tray_open(bs->dev_opaque); 1837 } 1838 return false; 1839 } 1840 1841 static void bdrv_dev_resize_cb(BlockDriverState *bs) 1842 { 1843 if (bs->dev_ops && bs->dev_ops->resize_cb) { 1844 bs->dev_ops->resize_cb(bs->dev_opaque); 1845 } 1846 } 1847 1848 bool bdrv_dev_is_medium_locked(BlockDriverState *bs) 1849 { 1850 if (bs->dev_ops && bs->dev_ops->is_medium_locked) { 1851 return bs->dev_ops->is_medium_locked(bs->dev_opaque); 1852 } 1853 return false; 1854 } 1855 1856 /* 1857 * Run consistency checks on an image 1858 * 1859 * Returns 0 if the check could be completed (it doesn't mean that the image is 1860 * free of errors) or -errno when an internal error occurred. The results of the 1861 * check are stored in res. 1862 */ 1863 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) 1864 { 1865 if (bs->drv->bdrv_check == NULL) { 1866 return -ENOTSUP; 1867 } 1868 1869 memset(res, 0, sizeof(*res)); 1870 return bs->drv->bdrv_check(bs, res, fix); 1871 } 1872 1873 #define COMMIT_BUF_SECTORS 2048 1874 1875 /* commit COW file into the raw image */ 1876 int bdrv_commit(BlockDriverState *bs) 1877 { 1878 BlockDriver *drv = bs->drv; 1879 int64_t sector, total_sectors; 1880 int n, ro, open_flags; 1881 int ret = 0; 1882 uint8_t *buf; 1883 char filename[PATH_MAX]; 1884 1885 if (!drv) 1886 return -ENOMEDIUM; 1887 1888 if (!bs->backing_hd) { 1889 return -ENOTSUP; 1890 } 1891 1892 if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) { 1893 return -EBUSY; 1894 } 1895 1896 ro = bs->backing_hd->read_only; 1897 /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */ 1898 pstrcpy(filename, sizeof(filename), bs->backing_hd->filename); 1899 open_flags = bs->backing_hd->open_flags; 1900 1901 if (ro) { 1902 if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) { 1903 return -EACCES; 1904 } 1905 } 1906 1907 total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS; 1908 buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); 1909 1910 for (sector = 0; sector < total_sectors; sector += n) { 1911 ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n); 1912 if (ret < 0) { 1913 goto ro_cleanup; 1914 } 1915 if (ret) { 1916 if (bdrv_read(bs, sector, buf, n) != 0) { 1917 ret = -EIO; 1918 goto ro_cleanup; 1919 } 1920 1921 if (bdrv_write(bs->backing_hd, sector, buf, n) != 0) { 1922 ret = -EIO; 1923 goto ro_cleanup; 1924 } 1925 } 1926 } 1927 1928 if (drv->bdrv_make_empty) { 1929 ret = drv->bdrv_make_empty(bs); 1930 bdrv_flush(bs); 1931 } 1932 1933 /* 1934 * Make sure all data we wrote to the backing device is actually 1935 * stable on disk. 1936 */ 1937 if (bs->backing_hd) 1938 bdrv_flush(bs->backing_hd); 1939 1940 ro_cleanup: 1941 g_free(buf); 1942 1943 if (ro) { 1944 /* ignoring error return here */ 1945 bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL); 1946 } 1947 1948 return ret; 1949 } 1950 1951 int bdrv_commit_all(void) 1952 { 1953 BlockDriverState *bs; 1954 1955 QTAILQ_FOREACH(bs, &bdrv_states, list) { 1956 if (bs->drv && bs->backing_hd) { 1957 int ret = bdrv_commit(bs); 1958 if (ret < 0) { 1959 return ret; 1960 } 1961 } 1962 } 1963 return 0; 1964 } 1965 1966 /** 1967 * Remove an active request from the tracked requests list 1968 * 1969 * This function should be called when a tracked request is completing. 1970 */ 1971 static void tracked_request_end(BdrvTrackedRequest *req) 1972 { 1973 QLIST_REMOVE(req, list); 1974 qemu_co_queue_restart_all(&req->wait_queue); 1975 } 1976 1977 /** 1978 * Add an active request to the tracked requests list 1979 */ 1980 static void tracked_request_begin(BdrvTrackedRequest *req, 1981 BlockDriverState *bs, 1982 int64_t sector_num, 1983 int nb_sectors, bool is_write) 1984 { 1985 *req = (BdrvTrackedRequest){ 1986 .bs = bs, 1987 .sector_num = sector_num, 1988 .nb_sectors = nb_sectors, 1989 .is_write = is_write, 1990 .co = qemu_coroutine_self(), 1991 }; 1992 1993 qemu_co_queue_init(&req->wait_queue); 1994 1995 QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); 1996 } 1997 1998 /** 1999 * Round a region to cluster boundaries 2000 */ 2001 void bdrv_round_to_clusters(BlockDriverState *bs, 2002 int64_t sector_num, int nb_sectors, 2003 int64_t *cluster_sector_num, 2004 int *cluster_nb_sectors) 2005 { 2006 BlockDriverInfo bdi; 2007 2008 if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { 2009 *cluster_sector_num = sector_num; 2010 *cluster_nb_sectors = nb_sectors; 2011 } else { 2012 int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE; 2013 *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c); 2014 *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num + 2015 nb_sectors, c); 2016 } 2017 } 2018 2019 static bool tracked_request_overlaps(BdrvTrackedRequest *req, 2020 int64_t sector_num, int nb_sectors) { 2021 /* aaaa bbbb */ 2022 if (sector_num >= req->sector_num + req->nb_sectors) { 2023 return false; 2024 } 2025 /* bbbb aaaa */ 2026 if (req->sector_num >= sector_num + nb_sectors) { 2027 return false; 2028 } 2029 return true; 2030 } 2031 2032 static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs, 2033 int64_t sector_num, int nb_sectors) 2034 { 2035 BdrvTrackedRequest *req; 2036 int64_t cluster_sector_num; 2037 int cluster_nb_sectors; 2038 bool retry; 2039 2040 /* If we touch the same cluster it counts as an overlap. This guarantees 2041 * that allocating writes will be serialized and not race with each other 2042 * for the same cluster. For example, in copy-on-read it ensures that the 2043 * CoR read and write operations are atomic and guest writes cannot 2044 * interleave between them. 2045 */ 2046 bdrv_round_to_clusters(bs, sector_num, nb_sectors, 2047 &cluster_sector_num, &cluster_nb_sectors); 2048 2049 do { 2050 retry = false; 2051 QLIST_FOREACH(req, &bs->tracked_requests, list) { 2052 if (tracked_request_overlaps(req, cluster_sector_num, 2053 cluster_nb_sectors)) { 2054 /* Hitting this means there was a reentrant request, for 2055 * example, a block driver issuing nested requests. This must 2056 * never happen since it means deadlock. 2057 */ 2058 assert(qemu_coroutine_self() != req->co); 2059 2060 qemu_co_queue_wait(&req->wait_queue); 2061 retry = true; 2062 break; 2063 } 2064 } 2065 } while (retry); 2066 } 2067 2068 /* 2069 * Return values: 2070 * 0 - success 2071 * -EINVAL - backing format specified, but no file 2072 * -ENOSPC - can't update the backing file because no space is left in the 2073 * image file header 2074 * -ENOTSUP - format driver doesn't support changing the backing file 2075 */ 2076 int bdrv_change_backing_file(BlockDriverState *bs, 2077 const char *backing_file, const char *backing_fmt) 2078 { 2079 BlockDriver *drv = bs->drv; 2080 int ret; 2081 2082 /* Backing file format doesn't make sense without a backing file */ 2083 if (backing_fmt && !backing_file) { 2084 return -EINVAL; 2085 } 2086 2087 if (drv->bdrv_change_backing_file != NULL) { 2088 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); 2089 } else { 2090 ret = -ENOTSUP; 2091 } 2092 2093 if (ret == 0) { 2094 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2095 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2096 } 2097 return ret; 2098 } 2099 2100 /* 2101 * Finds the image layer in the chain that has 'bs' as its backing file. 2102 * 2103 * active is the current topmost image. 2104 * 2105 * Returns NULL if bs is not found in active's image chain, 2106 * or if active == bs. 2107 */ 2108 BlockDriverState *bdrv_find_overlay(BlockDriverState *active, 2109 BlockDriverState *bs) 2110 { 2111 BlockDriverState *overlay = NULL; 2112 BlockDriverState *intermediate; 2113 2114 assert(active != NULL); 2115 assert(bs != NULL); 2116 2117 /* if bs is the same as active, then by definition it has no overlay 2118 */ 2119 if (active == bs) { 2120 return NULL; 2121 } 2122 2123 intermediate = active; 2124 while (intermediate->backing_hd) { 2125 if (intermediate->backing_hd == bs) { 2126 overlay = intermediate; 2127 break; 2128 } 2129 intermediate = intermediate->backing_hd; 2130 } 2131 2132 return overlay; 2133 } 2134 2135 typedef struct BlkIntermediateStates { 2136 BlockDriverState *bs; 2137 QSIMPLEQ_ENTRY(BlkIntermediateStates) entry; 2138 } BlkIntermediateStates; 2139 2140 2141 /* 2142 * Drops images above 'base' up to and including 'top', and sets the image 2143 * above 'top' to have base as its backing file. 2144 * 2145 * Requires that the overlay to 'top' is opened r/w, so that the backing file 2146 * information in 'bs' can be properly updated. 2147 * 2148 * E.g., this will convert the following chain: 2149 * bottom <- base <- intermediate <- top <- active 2150 * 2151 * to 2152 * 2153 * bottom <- base <- active 2154 * 2155 * It is allowed for bottom==base, in which case it converts: 2156 * 2157 * base <- intermediate <- top <- active 2158 * 2159 * to 2160 * 2161 * base <- active 2162 * 2163 * Error conditions: 2164 * if active == top, that is considered an error 2165 * 2166 */ 2167 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, 2168 BlockDriverState *base) 2169 { 2170 BlockDriverState *intermediate; 2171 BlockDriverState *base_bs = NULL; 2172 BlockDriverState *new_top_bs = NULL; 2173 BlkIntermediateStates *intermediate_state, *next; 2174 int ret = -EIO; 2175 2176 QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete; 2177 QSIMPLEQ_INIT(&states_to_delete); 2178 2179 if (!top->drv || !base->drv) { 2180 goto exit; 2181 } 2182 2183 new_top_bs = bdrv_find_overlay(active, top); 2184 2185 if (new_top_bs == NULL) { 2186 /* we could not find the image above 'top', this is an error */ 2187 goto exit; 2188 } 2189 2190 /* special case of new_top_bs->backing_hd already pointing to base - nothing 2191 * to do, no intermediate images */ 2192 if (new_top_bs->backing_hd == base) { 2193 ret = 0; 2194 goto exit; 2195 } 2196 2197 intermediate = top; 2198 2199 /* now we will go down through the list, and add each BDS we find 2200 * into our deletion queue, until we hit the 'base' 2201 */ 2202 while (intermediate) { 2203 intermediate_state = g_malloc0(sizeof(BlkIntermediateStates)); 2204 intermediate_state->bs = intermediate; 2205 QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry); 2206 2207 if (intermediate->backing_hd == base) { 2208 base_bs = intermediate->backing_hd; 2209 break; 2210 } 2211 intermediate = intermediate->backing_hd; 2212 } 2213 if (base_bs == NULL) { 2214 /* something went wrong, we did not end at the base. safely 2215 * unravel everything, and exit with error */ 2216 goto exit; 2217 } 2218 2219 /* success - we can delete the intermediate states, and link top->base */ 2220 ret = bdrv_change_backing_file(new_top_bs, base_bs->filename, 2221 base_bs->drv ? base_bs->drv->format_name : ""); 2222 if (ret) { 2223 goto exit; 2224 } 2225 new_top_bs->backing_hd = base_bs; 2226 2227 2228 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2229 /* so that bdrv_close() does not recursively close the chain */ 2230 intermediate_state->bs->backing_hd = NULL; 2231 bdrv_unref(intermediate_state->bs); 2232 } 2233 ret = 0; 2234 2235 exit: 2236 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2237 g_free(intermediate_state); 2238 } 2239 return ret; 2240 } 2241 2242 2243 static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, 2244 size_t size) 2245 { 2246 int64_t len; 2247 2248 if (!bdrv_is_inserted(bs)) 2249 return -ENOMEDIUM; 2250 2251 if (bs->growable) 2252 return 0; 2253 2254 len = bdrv_getlength(bs); 2255 2256 if (offset < 0) 2257 return -EIO; 2258 2259 if ((offset > len) || (len - offset < size)) 2260 return -EIO; 2261 2262 return 0; 2263 } 2264 2265 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, 2266 int nb_sectors) 2267 { 2268 return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE, 2269 nb_sectors * BDRV_SECTOR_SIZE); 2270 } 2271 2272 typedef struct RwCo { 2273 BlockDriverState *bs; 2274 int64_t sector_num; 2275 int nb_sectors; 2276 QEMUIOVector *qiov; 2277 bool is_write; 2278 int ret; 2279 BdrvRequestFlags flags; 2280 } RwCo; 2281 2282 static void coroutine_fn bdrv_rw_co_entry(void *opaque) 2283 { 2284 RwCo *rwco = opaque; 2285 2286 if (!rwco->is_write) { 2287 rwco->ret = bdrv_co_do_readv(rwco->bs, rwco->sector_num, 2288 rwco->nb_sectors, rwco->qiov, 2289 rwco->flags); 2290 } else { 2291 rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num, 2292 rwco->nb_sectors, rwco->qiov, 2293 rwco->flags); 2294 } 2295 } 2296 2297 /* 2298 * Process a vectored synchronous request using coroutines 2299 */ 2300 static int bdrv_rwv_co(BlockDriverState *bs, int64_t sector_num, 2301 QEMUIOVector *qiov, bool is_write, 2302 BdrvRequestFlags flags) 2303 { 2304 Coroutine *co; 2305 RwCo rwco = { 2306 .bs = bs, 2307 .sector_num = sector_num, 2308 .nb_sectors = qiov->size >> BDRV_SECTOR_BITS, 2309 .qiov = qiov, 2310 .is_write = is_write, 2311 .ret = NOT_DONE, 2312 .flags = flags, 2313 }; 2314 assert((qiov->size & (BDRV_SECTOR_SIZE - 1)) == 0); 2315 2316 /** 2317 * In sync call context, when the vcpu is blocked, this throttling timer 2318 * will not fire; so the I/O throttling function has to be disabled here 2319 * if it has been enabled. 2320 */ 2321 if (bs->io_limits_enabled) { 2322 fprintf(stderr, "Disabling I/O throttling on '%s' due " 2323 "to synchronous I/O.\n", bdrv_get_device_name(bs)); 2324 bdrv_io_limits_disable(bs); 2325 } 2326 2327 if (qemu_in_coroutine()) { 2328 /* Fast-path if already in coroutine context */ 2329 bdrv_rw_co_entry(&rwco); 2330 } else { 2331 co = qemu_coroutine_create(bdrv_rw_co_entry); 2332 qemu_coroutine_enter(co, &rwco); 2333 while (rwco.ret == NOT_DONE) { 2334 qemu_aio_wait(); 2335 } 2336 } 2337 return rwco.ret; 2338 } 2339 2340 /* 2341 * Process a synchronous request using coroutines 2342 */ 2343 static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, 2344 int nb_sectors, bool is_write, BdrvRequestFlags flags) 2345 { 2346 QEMUIOVector qiov; 2347 struct iovec iov = { 2348 .iov_base = (void *)buf, 2349 .iov_len = nb_sectors * BDRV_SECTOR_SIZE, 2350 }; 2351 2352 qemu_iovec_init_external(&qiov, &iov, 1); 2353 return bdrv_rwv_co(bs, sector_num, &qiov, is_write, flags); 2354 } 2355 2356 /* return < 0 if error. See bdrv_write() for the return codes */ 2357 int bdrv_read(BlockDriverState *bs, int64_t sector_num, 2358 uint8_t *buf, int nb_sectors) 2359 { 2360 return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0); 2361 } 2362 2363 /* Just like bdrv_read(), but with I/O throttling temporarily disabled */ 2364 int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, 2365 uint8_t *buf, int nb_sectors) 2366 { 2367 bool enabled; 2368 int ret; 2369 2370 enabled = bs->io_limits_enabled; 2371 bs->io_limits_enabled = false; 2372 ret = bdrv_read(bs, sector_num, buf, nb_sectors); 2373 bs->io_limits_enabled = enabled; 2374 return ret; 2375 } 2376 2377 /* Return < 0 if error. Important errors are: 2378 -EIO generic I/O error (may happen for all errors) 2379 -ENOMEDIUM No media inserted. 2380 -EINVAL Invalid sector number or nb_sectors 2381 -EACCES Trying to write a read-only device 2382 */ 2383 int bdrv_write(BlockDriverState *bs, int64_t sector_num, 2384 const uint8_t *buf, int nb_sectors) 2385 { 2386 return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0); 2387 } 2388 2389 int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov) 2390 { 2391 return bdrv_rwv_co(bs, sector_num, qiov, true, 0); 2392 } 2393 2394 int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, 2395 int nb_sectors, BdrvRequestFlags flags) 2396 { 2397 return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true, 2398 BDRV_REQ_ZERO_WRITE | flags); 2399 } 2400 2401 /* 2402 * Completely zero out a block device with the help of bdrv_write_zeroes. 2403 * The operation is sped up by checking the block status and only writing 2404 * zeroes to the device if they currently do not return zeroes. Optional 2405 * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). 2406 * 2407 * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). 2408 */ 2409 int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) 2410 { 2411 int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; 2412 int64_t ret, nb_sectors, sector_num = 0; 2413 int n; 2414 2415 for (;;) { 2416 nb_sectors = target_size - sector_num; 2417 if (nb_sectors <= 0) { 2418 return 0; 2419 } 2420 if (nb_sectors > INT_MAX) { 2421 nb_sectors = INT_MAX; 2422 } 2423 ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); 2424 if (ret < 0) { 2425 error_report("error getting block status at sector %" PRId64 ": %s", 2426 sector_num, strerror(-ret)); 2427 return ret; 2428 } 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. Block drivers can expect the "bulk" of the request 2775 * to be aligned. 2776 */ 2777 if (bs->bl.write_zeroes_alignment 2778 && num > bs->bl.write_zeroes_alignment) { 2779 if (sector_num % bs->bl.write_zeroes_alignment != 0) { 2780 /* Make a small request up to the first aligned sector. */ 2781 num = bs->bl.write_zeroes_alignment; 2782 num -= sector_num % bs->bl.write_zeroes_alignment; 2783 } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) { 2784 /* Shorten the request to the last aligned sector. num cannot 2785 * underflow because num > bs->bl.write_zeroes_alignment. 2786 */ 2787 num -= (sector_num + num) % bs->bl.write_zeroes_alignment; 2788 } 2789 } 2790 2791 /* limit request size */ 2792 if (num > max_write_zeroes) { 2793 num = max_write_zeroes; 2794 } 2795 2796 ret = -ENOTSUP; 2797 /* First try the efficient write zeroes operation */ 2798 if (drv->bdrv_co_write_zeroes) { 2799 ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags); 2800 } 2801 2802 if (ret == -ENOTSUP) { 2803 /* Fall back to bounce buffer if write zeroes is unsupported */ 2804 iov.iov_len = num * BDRV_SECTOR_SIZE; 2805 if (iov.iov_base == NULL) { 2806 iov.iov_base = qemu_blockalign(bs, num * BDRV_SECTOR_SIZE); 2807 memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE); 2808 } 2809 qemu_iovec_init_external(&qiov, &iov, 1); 2810 2811 ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov); 2812 2813 /* Keep bounce buffer around if it is big enough for all 2814 * all future requests. 2815 */ 2816 if (num < max_write_zeroes) { 2817 qemu_vfree(iov.iov_base); 2818 iov.iov_base = NULL; 2819 } 2820 } 2821 2822 sector_num += num; 2823 nb_sectors -= num; 2824 } 2825 2826 qemu_vfree(iov.iov_base); 2827 return ret; 2828 } 2829 2830 /* 2831 * Handle a write request in coroutine context 2832 */ 2833 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 2834 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 2835 BdrvRequestFlags flags) 2836 { 2837 BlockDriver *drv = bs->drv; 2838 BdrvTrackedRequest req; 2839 int ret; 2840 2841 if (!bs->drv) { 2842 return -ENOMEDIUM; 2843 } 2844 if (bs->read_only) { 2845 return -EACCES; 2846 } 2847 if (bdrv_check_request(bs, sector_num, nb_sectors)) { 2848 return -EIO; 2849 } 2850 2851 if (bs->copy_on_read_in_flight) { 2852 wait_for_overlapping_requests(bs, sector_num, nb_sectors); 2853 } 2854 2855 /* throttling disk I/O */ 2856 if (bs->io_limits_enabled) { 2857 bdrv_io_limits_intercept(bs, nb_sectors, true); 2858 } 2859 2860 tracked_request_begin(&req, bs, sector_num, nb_sectors, true); 2861 2862 ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req); 2863 2864 if (ret < 0) { 2865 /* Do nothing, write notifier decided to fail this request */ 2866 } else if (flags & BDRV_REQ_ZERO_WRITE) { 2867 ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); 2868 } else { 2869 ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); 2870 } 2871 2872 if (ret == 0 && !bs->enable_write_cache) { 2873 ret = bdrv_co_flush(bs); 2874 } 2875 2876 bdrv_set_dirty(bs, sector_num, nb_sectors); 2877 2878 if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { 2879 bs->wr_highest_sector = sector_num + nb_sectors - 1; 2880 } 2881 if (bs->growable && ret >= 0) { 2882 bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); 2883 } 2884 2885 tracked_request_end(&req); 2886 2887 return ret; 2888 } 2889 2890 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, 2891 int nb_sectors, QEMUIOVector *qiov) 2892 { 2893 trace_bdrv_co_writev(bs, sector_num, nb_sectors); 2894 2895 return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0); 2896 } 2897 2898 int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, 2899 int64_t sector_num, int nb_sectors, 2900 BdrvRequestFlags flags) 2901 { 2902 trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags); 2903 2904 if (!(bs->open_flags & BDRV_O_UNMAP)) { 2905 flags &= ~BDRV_REQ_MAY_UNMAP; 2906 } 2907 2908 return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, 2909 BDRV_REQ_ZERO_WRITE | flags); 2910 } 2911 2912 /** 2913 * Truncate file to 'offset' bytes (needed only for file protocols) 2914 */ 2915 int bdrv_truncate(BlockDriverState *bs, int64_t offset) 2916 { 2917 BlockDriver *drv = bs->drv; 2918 int ret; 2919 if (!drv) 2920 return -ENOMEDIUM; 2921 if (!drv->bdrv_truncate) 2922 return -ENOTSUP; 2923 if (bs->read_only) 2924 return -EACCES; 2925 if (bdrv_in_use(bs)) 2926 return -EBUSY; 2927 ret = drv->bdrv_truncate(bs, offset); 2928 if (ret == 0) { 2929 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); 2930 bdrv_dev_resize_cb(bs); 2931 } 2932 return ret; 2933 } 2934 2935 /** 2936 * Length of a allocated file in bytes. Sparse files are counted by actual 2937 * allocated space. Return < 0 if error or unknown. 2938 */ 2939 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) 2940 { 2941 BlockDriver *drv = bs->drv; 2942 if (!drv) { 2943 return -ENOMEDIUM; 2944 } 2945 if (drv->bdrv_get_allocated_file_size) { 2946 return drv->bdrv_get_allocated_file_size(bs); 2947 } 2948 if (bs->file) { 2949 return bdrv_get_allocated_file_size(bs->file); 2950 } 2951 return -ENOTSUP; 2952 } 2953 2954 /** 2955 * Length of a file in bytes. Return < 0 if error or unknown. 2956 */ 2957 int64_t bdrv_getlength(BlockDriverState *bs) 2958 { 2959 BlockDriver *drv = bs->drv; 2960 if (!drv) 2961 return -ENOMEDIUM; 2962 2963 if (drv->has_variable_length) { 2964 int ret = refresh_total_sectors(bs, bs->total_sectors); 2965 if (ret < 0) { 2966 return ret; 2967 } 2968 } 2969 return bs->total_sectors * BDRV_SECTOR_SIZE; 2970 } 2971 2972 /* return 0 as number of sectors if no device present or error */ 2973 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) 2974 { 2975 int64_t length; 2976 length = bdrv_getlength(bs); 2977 if (length < 0) 2978 length = 0; 2979 else 2980 length = length >> BDRV_SECTOR_BITS; 2981 *nb_sectors_ptr = length; 2982 } 2983 2984 void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error, 2985 BlockdevOnError on_write_error) 2986 { 2987 bs->on_read_error = on_read_error; 2988 bs->on_write_error = on_write_error; 2989 } 2990 2991 BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read) 2992 { 2993 return is_read ? bs->on_read_error : bs->on_write_error; 2994 } 2995 2996 BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error) 2997 { 2998 BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error; 2999 3000 switch (on_err) { 3001 case BLOCKDEV_ON_ERROR_ENOSPC: 3002 return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT; 3003 case BLOCKDEV_ON_ERROR_STOP: 3004 return BDRV_ACTION_STOP; 3005 case BLOCKDEV_ON_ERROR_REPORT: 3006 return BDRV_ACTION_REPORT; 3007 case BLOCKDEV_ON_ERROR_IGNORE: 3008 return BDRV_ACTION_IGNORE; 3009 default: 3010 abort(); 3011 } 3012 } 3013 3014 /* This is done by device models because, while the block layer knows 3015 * about the error, it does not know whether an operation comes from 3016 * the device or the block layer (from a job, for example). 3017 */ 3018 void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action, 3019 bool is_read, int error) 3020 { 3021 assert(error >= 0); 3022 bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read); 3023 if (action == BDRV_ACTION_STOP) { 3024 vm_stop(RUN_STATE_IO_ERROR); 3025 bdrv_iostatus_set_err(bs, error); 3026 } 3027 } 3028 3029 int bdrv_is_read_only(BlockDriverState *bs) 3030 { 3031 return bs->read_only; 3032 } 3033 3034 int bdrv_is_sg(BlockDriverState *bs) 3035 { 3036 return bs->sg; 3037 } 3038 3039 int bdrv_enable_write_cache(BlockDriverState *bs) 3040 { 3041 return bs->enable_write_cache; 3042 } 3043 3044 void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce) 3045 { 3046 bs->enable_write_cache = wce; 3047 3048 /* so a reopen() will preserve wce */ 3049 if (wce) { 3050 bs->open_flags |= BDRV_O_CACHE_WB; 3051 } else { 3052 bs->open_flags &= ~BDRV_O_CACHE_WB; 3053 } 3054 } 3055 3056 int bdrv_is_encrypted(BlockDriverState *bs) 3057 { 3058 if (bs->backing_hd && bs->backing_hd->encrypted) 3059 return 1; 3060 return bs->encrypted; 3061 } 3062 3063 int bdrv_key_required(BlockDriverState *bs) 3064 { 3065 BlockDriverState *backing_hd = bs->backing_hd; 3066 3067 if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key) 3068 return 1; 3069 return (bs->encrypted && !bs->valid_key); 3070 } 3071 3072 int bdrv_set_key(BlockDriverState *bs, const char *key) 3073 { 3074 int ret; 3075 if (bs->backing_hd && bs->backing_hd->encrypted) { 3076 ret = bdrv_set_key(bs->backing_hd, key); 3077 if (ret < 0) 3078 return ret; 3079 if (!bs->encrypted) 3080 return 0; 3081 } 3082 if (!bs->encrypted) { 3083 return -EINVAL; 3084 } else if (!bs->drv || !bs->drv->bdrv_set_key) { 3085 return -ENOMEDIUM; 3086 } 3087 ret = bs->drv->bdrv_set_key(bs, key); 3088 if (ret < 0) { 3089 bs->valid_key = 0; 3090 } else if (!bs->valid_key) { 3091 bs->valid_key = 1; 3092 /* call the change callback now, we skipped it on open */ 3093 bdrv_dev_change_media_cb(bs, true); 3094 } 3095 return ret; 3096 } 3097 3098 const char *bdrv_get_format_name(BlockDriverState *bs) 3099 { 3100 return bs->drv ? bs->drv->format_name : NULL; 3101 } 3102 3103 void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 3104 void *opaque) 3105 { 3106 BlockDriver *drv; 3107 3108 QLIST_FOREACH(drv, &bdrv_drivers, list) { 3109 it(opaque, drv->format_name); 3110 } 3111 } 3112 3113 BlockDriverState *bdrv_find(const char *name) 3114 { 3115 BlockDriverState *bs; 3116 3117 QTAILQ_FOREACH(bs, &bdrv_states, list) { 3118 if (!strcmp(name, bs->device_name)) { 3119 return bs; 3120 } 3121 } 3122 return NULL; 3123 } 3124 3125 BlockDriverState *bdrv_next(BlockDriverState *bs) 3126 { 3127 if (!bs) { 3128 return QTAILQ_FIRST(&bdrv_states); 3129 } 3130 return QTAILQ_NEXT(bs, list); 3131 } 3132 3133 void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque) 3134 { 3135 BlockDriverState *bs; 3136 3137 QTAILQ_FOREACH(bs, &bdrv_states, list) { 3138 it(opaque, bs); 3139 } 3140 } 3141 3142 const char *bdrv_get_device_name(BlockDriverState *bs) 3143 { 3144 return bs->device_name; 3145 } 3146 3147 int bdrv_get_flags(BlockDriverState *bs) 3148 { 3149 return bs->open_flags; 3150 } 3151 3152 int bdrv_flush_all(void) 3153 { 3154 BlockDriverState *bs; 3155 int result = 0; 3156 3157 QTAILQ_FOREACH(bs, &bdrv_states, list) { 3158 int ret = bdrv_flush(bs); 3159 if (ret < 0 && !result) { 3160 result = ret; 3161 } 3162 } 3163 3164 return result; 3165 } 3166 3167 int bdrv_has_zero_init_1(BlockDriverState *bs) 3168 { 3169 return 1; 3170 } 3171 3172 int bdrv_has_zero_init(BlockDriverState *bs) 3173 { 3174 assert(bs->drv); 3175 3176 /* If BS is a copy on write image, it is initialized to 3177 the contents of the base image, which may not be zeroes. */ 3178 if (bs->backing_hd) { 3179 return 0; 3180 } 3181 if (bs->drv->bdrv_has_zero_init) { 3182 return bs->drv->bdrv_has_zero_init(bs); 3183 } 3184 3185 /* safe default */ 3186 return 0; 3187 } 3188 3189 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) 3190 { 3191 BlockDriverInfo bdi; 3192 3193 if (bs->backing_hd) { 3194 return false; 3195 } 3196 3197 if (bdrv_get_info(bs, &bdi) == 0) { 3198 return bdi.unallocated_blocks_are_zero; 3199 } 3200 3201 return false; 3202 } 3203 3204 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) 3205 { 3206 BlockDriverInfo bdi; 3207 3208 if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { 3209 return false; 3210 } 3211 3212 if (bdrv_get_info(bs, &bdi) == 0) { 3213 return bdi.can_write_zeroes_with_unmap; 3214 } 3215 3216 return false; 3217 } 3218 3219 typedef struct BdrvCoGetBlockStatusData { 3220 BlockDriverState *bs; 3221 BlockDriverState *base; 3222 int64_t sector_num; 3223 int nb_sectors; 3224 int *pnum; 3225 int64_t ret; 3226 bool done; 3227 } BdrvCoGetBlockStatusData; 3228 3229 /* 3230 * Returns true iff the specified sector is present in the disk image. Drivers 3231 * not implementing the functionality are assumed to not support backing files, 3232 * hence all their sectors are reported as allocated. 3233 * 3234 * If 'sector_num' is beyond the end of the disk image the return value is 0 3235 * and 'pnum' is set to 0. 3236 * 3237 * 'pnum' is set to the number of sectors (including and immediately following 3238 * the specified sector) that are known to be in the same 3239 * allocated/unallocated state. 3240 * 3241 * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes 3242 * beyond the end of the disk image it will be clamped. 3243 */ 3244 static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, 3245 int64_t sector_num, 3246 int nb_sectors, int *pnum) 3247 { 3248 int64_t length; 3249 int64_t n; 3250 int64_t ret, ret2; 3251 3252 length = bdrv_getlength(bs); 3253 if (length < 0) { 3254 return length; 3255 } 3256 3257 if (sector_num >= (length >> BDRV_SECTOR_BITS)) { 3258 *pnum = 0; 3259 return 0; 3260 } 3261 3262 n = bs->total_sectors - sector_num; 3263 if (n < nb_sectors) { 3264 nb_sectors = n; 3265 } 3266 3267 if (!bs->drv->bdrv_co_get_block_status) { 3268 *pnum = nb_sectors; 3269 ret = BDRV_BLOCK_DATA; 3270 if (bs->drv->protocol_name) { 3271 ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); 3272 } 3273 return ret; 3274 } 3275 3276 ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); 3277 if (ret < 0) { 3278 *pnum = 0; 3279 return ret; 3280 } 3281 3282 if (ret & BDRV_BLOCK_RAW) { 3283 assert(ret & BDRV_BLOCK_OFFSET_VALID); 3284 return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3285 *pnum, pnum); 3286 } 3287 3288 if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { 3289 if (bdrv_unallocated_blocks_are_zero(bs)) { 3290 ret |= BDRV_BLOCK_ZERO; 3291 } else if (bs->backing_hd) { 3292 BlockDriverState *bs2 = bs->backing_hd; 3293 int64_t length2 = bdrv_getlength(bs2); 3294 if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) { 3295 ret |= BDRV_BLOCK_ZERO; 3296 } 3297 } 3298 } 3299 3300 if (bs->file && 3301 (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && 3302 (ret & BDRV_BLOCK_OFFSET_VALID)) { 3303 ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3304 *pnum, pnum); 3305 if (ret2 >= 0) { 3306 /* Ignore errors. This is just providing extra information, it 3307 * is useful but not necessary. 3308 */ 3309 ret |= (ret2 & BDRV_BLOCK_ZERO); 3310 } 3311 } 3312 3313 return ret; 3314 } 3315 3316 /* Coroutine wrapper for bdrv_get_block_status() */ 3317 static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque) 3318 { 3319 BdrvCoGetBlockStatusData *data = opaque; 3320 BlockDriverState *bs = data->bs; 3321 3322 data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors, 3323 data->pnum); 3324 data->done = true; 3325 } 3326 3327 /* 3328 * Synchronous wrapper around bdrv_co_get_block_status(). 3329 * 3330 * See bdrv_co_get_block_status() for details. 3331 */ 3332 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, 3333 int nb_sectors, int *pnum) 3334 { 3335 Coroutine *co; 3336 BdrvCoGetBlockStatusData data = { 3337 .bs = bs, 3338 .sector_num = sector_num, 3339 .nb_sectors = nb_sectors, 3340 .pnum = pnum, 3341 .done = false, 3342 }; 3343 3344 if (qemu_in_coroutine()) { 3345 /* Fast-path if already in coroutine context */ 3346 bdrv_get_block_status_co_entry(&data); 3347 } else { 3348 co = qemu_coroutine_create(bdrv_get_block_status_co_entry); 3349 qemu_coroutine_enter(co, &data); 3350 while (!data.done) { 3351 qemu_aio_wait(); 3352 } 3353 } 3354 return data.ret; 3355 } 3356 3357 int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, 3358 int nb_sectors, int *pnum) 3359 { 3360 int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); 3361 if (ret < 0) { 3362 return ret; 3363 } 3364 return 3365 (ret & BDRV_BLOCK_DATA) || 3366 ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); 3367 } 3368 3369 /* 3370 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] 3371 * 3372 * Return true if the given sector is allocated in any image between 3373 * BASE and TOP (inclusive). BASE can be NULL to check if the given 3374 * sector is allocated in any image of the chain. Return false otherwise. 3375 * 3376 * 'pnum' is set to the number of sectors (including and immediately following 3377 * the specified sector) that are known to be in the same 3378 * allocated/unallocated state. 3379 * 3380 */ 3381 int bdrv_is_allocated_above(BlockDriverState *top, 3382 BlockDriverState *base, 3383 int64_t sector_num, 3384 int nb_sectors, int *pnum) 3385 { 3386 BlockDriverState *intermediate; 3387 int ret, n = nb_sectors; 3388 3389 intermediate = top; 3390 while (intermediate && intermediate != base) { 3391 int pnum_inter; 3392 ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors, 3393 &pnum_inter); 3394 if (ret < 0) { 3395 return ret; 3396 } else if (ret) { 3397 *pnum = pnum_inter; 3398 return 1; 3399 } 3400 3401 /* 3402 * [sector_num, nb_sectors] is unallocated on top but intermediate 3403 * might have 3404 * 3405 * [sector_num+x, nr_sectors] allocated. 3406 */ 3407 if (n > pnum_inter && 3408 (intermediate == top || 3409 sector_num + pnum_inter < intermediate->total_sectors)) { 3410 n = pnum_inter; 3411 } 3412 3413 intermediate = intermediate->backing_hd; 3414 } 3415 3416 *pnum = n; 3417 return 0; 3418 } 3419 3420 const char *bdrv_get_encrypted_filename(BlockDriverState *bs) 3421 { 3422 if (bs->backing_hd && bs->backing_hd->encrypted) 3423 return bs->backing_file; 3424 else if (bs->encrypted) 3425 return bs->filename; 3426 else 3427 return NULL; 3428 } 3429 3430 void bdrv_get_backing_filename(BlockDriverState *bs, 3431 char *filename, int filename_size) 3432 { 3433 pstrcpy(filename, filename_size, bs->backing_file); 3434 } 3435 3436 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num, 3437 const uint8_t *buf, int nb_sectors) 3438 { 3439 BlockDriver *drv = bs->drv; 3440 if (!drv) 3441 return -ENOMEDIUM; 3442 if (!drv->bdrv_write_compressed) 3443 return -ENOTSUP; 3444 if (bdrv_check_request(bs, sector_num, nb_sectors)) 3445 return -EIO; 3446 3447 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 3448 3449 return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors); 3450 } 3451 3452 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3453 { 3454 BlockDriver *drv = bs->drv; 3455 if (!drv) 3456 return -ENOMEDIUM; 3457 if (!drv->bdrv_get_info) 3458 return -ENOTSUP; 3459 memset(bdi, 0, sizeof(*bdi)); 3460 return drv->bdrv_get_info(bs, bdi); 3461 } 3462 3463 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) 3464 { 3465 BlockDriver *drv = bs->drv; 3466 if (drv && drv->bdrv_get_specific_info) { 3467 return drv->bdrv_get_specific_info(bs); 3468 } 3469 return NULL; 3470 } 3471 3472 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 3473 int64_t pos, int size) 3474 { 3475 QEMUIOVector qiov; 3476 struct iovec iov = { 3477 .iov_base = (void *) buf, 3478 .iov_len = size, 3479 }; 3480 3481 qemu_iovec_init_external(&qiov, &iov, 1); 3482 return bdrv_writev_vmstate(bs, &qiov, pos); 3483 } 3484 3485 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) 3486 { 3487 BlockDriver *drv = bs->drv; 3488 3489 if (!drv) { 3490 return -ENOMEDIUM; 3491 } else if (drv->bdrv_save_vmstate) { 3492 return drv->bdrv_save_vmstate(bs, qiov, pos); 3493 } else if (bs->file) { 3494 return bdrv_writev_vmstate(bs->file, qiov, pos); 3495 } 3496 3497 return -ENOTSUP; 3498 } 3499 3500 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 3501 int64_t pos, int size) 3502 { 3503 BlockDriver *drv = bs->drv; 3504 if (!drv) 3505 return -ENOMEDIUM; 3506 if (drv->bdrv_load_vmstate) 3507 return drv->bdrv_load_vmstate(bs, buf, pos, size); 3508 if (bs->file) 3509 return bdrv_load_vmstate(bs->file, buf, pos, size); 3510 return -ENOTSUP; 3511 } 3512 3513 void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event) 3514 { 3515 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { 3516 return; 3517 } 3518 3519 bs->drv->bdrv_debug_event(bs, event); 3520 } 3521 3522 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, 3523 const char *tag) 3524 { 3525 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { 3526 bs = bs->file; 3527 } 3528 3529 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { 3530 return bs->drv->bdrv_debug_breakpoint(bs, event, tag); 3531 } 3532 3533 return -ENOTSUP; 3534 } 3535 3536 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) 3537 { 3538 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { 3539 bs = bs->file; 3540 } 3541 3542 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { 3543 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); 3544 } 3545 3546 return -ENOTSUP; 3547 } 3548 3549 int bdrv_debug_resume(BlockDriverState *bs, const char *tag) 3550 { 3551 while (bs && bs->drv && !bs->drv->bdrv_debug_resume) { 3552 bs = bs->file; 3553 } 3554 3555 if (bs && bs->drv && bs->drv->bdrv_debug_resume) { 3556 return bs->drv->bdrv_debug_resume(bs, tag); 3557 } 3558 3559 return -ENOTSUP; 3560 } 3561 3562 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) 3563 { 3564 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { 3565 bs = bs->file; 3566 } 3567 3568 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { 3569 return bs->drv->bdrv_debug_is_suspended(bs, tag); 3570 } 3571 3572 return false; 3573 } 3574 3575 int bdrv_is_snapshot(BlockDriverState *bs) 3576 { 3577 return !!(bs->open_flags & BDRV_O_SNAPSHOT); 3578 } 3579 3580 /* backing_file can either be relative, or absolute, or a protocol. If it is 3581 * relative, it must be relative to the chain. So, passing in bs->filename 3582 * from a BDS as backing_file should not be done, as that may be relative to 3583 * the CWD rather than the chain. */ 3584 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 3585 const char *backing_file) 3586 { 3587 char *filename_full = NULL; 3588 char *backing_file_full = NULL; 3589 char *filename_tmp = NULL; 3590 int is_protocol = 0; 3591 BlockDriverState *curr_bs = NULL; 3592 BlockDriverState *retval = NULL; 3593 3594 if (!bs || !bs->drv || !backing_file) { 3595 return NULL; 3596 } 3597 3598 filename_full = g_malloc(PATH_MAX); 3599 backing_file_full = g_malloc(PATH_MAX); 3600 filename_tmp = g_malloc(PATH_MAX); 3601 3602 is_protocol = path_has_protocol(backing_file); 3603 3604 for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) { 3605 3606 /* If either of the filename paths is actually a protocol, then 3607 * compare unmodified paths; otherwise make paths relative */ 3608 if (is_protocol || path_has_protocol(curr_bs->backing_file)) { 3609 if (strcmp(backing_file, curr_bs->backing_file) == 0) { 3610 retval = curr_bs->backing_hd; 3611 break; 3612 } 3613 } else { 3614 /* If not an absolute filename path, make it relative to the current 3615 * image's filename path */ 3616 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3617 backing_file); 3618 3619 /* We are going to compare absolute pathnames */ 3620 if (!realpath(filename_tmp, filename_full)) { 3621 continue; 3622 } 3623 3624 /* We need to make sure the backing filename we are comparing against 3625 * is relative to the current image filename (or absolute) */ 3626 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3627 curr_bs->backing_file); 3628 3629 if (!realpath(filename_tmp, backing_file_full)) { 3630 continue; 3631 } 3632 3633 if (strcmp(backing_file_full, filename_full) == 0) { 3634 retval = curr_bs->backing_hd; 3635 break; 3636 } 3637 } 3638 } 3639 3640 g_free(filename_full); 3641 g_free(backing_file_full); 3642 g_free(filename_tmp); 3643 return retval; 3644 } 3645 3646 int bdrv_get_backing_file_depth(BlockDriverState *bs) 3647 { 3648 if (!bs->drv) { 3649 return 0; 3650 } 3651 3652 if (!bs->backing_hd) { 3653 return 0; 3654 } 3655 3656 return 1 + bdrv_get_backing_file_depth(bs->backing_hd); 3657 } 3658 3659 BlockDriverState *bdrv_find_base(BlockDriverState *bs) 3660 { 3661 BlockDriverState *curr_bs = NULL; 3662 3663 if (!bs) { 3664 return NULL; 3665 } 3666 3667 curr_bs = bs; 3668 3669 while (curr_bs->backing_hd) { 3670 curr_bs = curr_bs->backing_hd; 3671 } 3672 return curr_bs; 3673 } 3674 3675 /**************************************************************/ 3676 /* async I/Os */ 3677 3678 BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, 3679 QEMUIOVector *qiov, int nb_sectors, 3680 BlockDriverCompletionFunc *cb, void *opaque) 3681 { 3682 trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); 3683 3684 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 3685 cb, opaque, false); 3686 } 3687 3688 BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, 3689 QEMUIOVector *qiov, int nb_sectors, 3690 BlockDriverCompletionFunc *cb, void *opaque) 3691 { 3692 trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); 3693 3694 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 3695 cb, opaque, true); 3696 } 3697 3698 BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, 3699 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags, 3700 BlockDriverCompletionFunc *cb, void *opaque) 3701 { 3702 trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque); 3703 3704 return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors, 3705 BDRV_REQ_ZERO_WRITE | flags, 3706 cb, opaque, true); 3707 } 3708 3709 3710 typedef struct MultiwriteCB { 3711 int error; 3712 int num_requests; 3713 int num_callbacks; 3714 struct { 3715 BlockDriverCompletionFunc *cb; 3716 void *opaque; 3717 QEMUIOVector *free_qiov; 3718 } callbacks[]; 3719 } MultiwriteCB; 3720 3721 static void multiwrite_user_cb(MultiwriteCB *mcb) 3722 { 3723 int i; 3724 3725 for (i = 0; i < mcb->num_callbacks; i++) { 3726 mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error); 3727 if (mcb->callbacks[i].free_qiov) { 3728 qemu_iovec_destroy(mcb->callbacks[i].free_qiov); 3729 } 3730 g_free(mcb->callbacks[i].free_qiov); 3731 } 3732 } 3733 3734 static void multiwrite_cb(void *opaque, int ret) 3735 { 3736 MultiwriteCB *mcb = opaque; 3737 3738 trace_multiwrite_cb(mcb, ret); 3739 3740 if (ret < 0 && !mcb->error) { 3741 mcb->error = ret; 3742 } 3743 3744 mcb->num_requests--; 3745 if (mcb->num_requests == 0) { 3746 multiwrite_user_cb(mcb); 3747 g_free(mcb); 3748 } 3749 } 3750 3751 static int multiwrite_req_compare(const void *a, const void *b) 3752 { 3753 const BlockRequest *req1 = a, *req2 = b; 3754 3755 /* 3756 * Note that we can't simply subtract req2->sector from req1->sector 3757 * here as that could overflow the return value. 3758 */ 3759 if (req1->sector > req2->sector) { 3760 return 1; 3761 } else if (req1->sector < req2->sector) { 3762 return -1; 3763 } else { 3764 return 0; 3765 } 3766 } 3767 3768 /* 3769 * Takes a bunch of requests and tries to merge them. Returns the number of 3770 * requests that remain after merging. 3771 */ 3772 static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, 3773 int num_reqs, MultiwriteCB *mcb) 3774 { 3775 int i, outidx; 3776 3777 // Sort requests by start sector 3778 qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare); 3779 3780 // Check if adjacent requests touch the same clusters. If so, combine them, 3781 // filling up gaps with zero sectors. 3782 outidx = 0; 3783 for (i = 1; i < num_reqs; i++) { 3784 int merge = 0; 3785 int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors; 3786 3787 // Handle exactly sequential writes and overlapping writes. 3788 if (reqs[i].sector <= oldreq_last) { 3789 merge = 1; 3790 } 3791 3792 if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { 3793 merge = 0; 3794 } 3795 3796 if (merge) { 3797 size_t size; 3798 QEMUIOVector *qiov = g_malloc0(sizeof(*qiov)); 3799 qemu_iovec_init(qiov, 3800 reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1); 3801 3802 // Add the first request to the merged one. If the requests are 3803 // overlapping, drop the last sectors of the first request. 3804 size = (reqs[i].sector - reqs[outidx].sector) << 9; 3805 qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size); 3806 3807 // We should need to add any zeros between the two requests 3808 assert (reqs[i].sector <= oldreq_last); 3809 3810 // Add the second request 3811 qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size); 3812 3813 reqs[outidx].nb_sectors = qiov->size >> 9; 3814 reqs[outidx].qiov = qiov; 3815 3816 mcb->callbacks[i].free_qiov = reqs[outidx].qiov; 3817 } else { 3818 outidx++; 3819 reqs[outidx].sector = reqs[i].sector; 3820 reqs[outidx].nb_sectors = reqs[i].nb_sectors; 3821 reqs[outidx].qiov = reqs[i].qiov; 3822 } 3823 } 3824 3825 return outidx + 1; 3826 } 3827 3828 /* 3829 * Submit multiple AIO write requests at once. 3830 * 3831 * On success, the function returns 0 and all requests in the reqs array have 3832 * been submitted. In error case this function returns -1, and any of the 3833 * requests may or may not be submitted yet. In particular, this means that the 3834 * callback will be called for some of the requests, for others it won't. The 3835 * caller must check the error field of the BlockRequest to wait for the right 3836 * callbacks (if error != 0, no callback will be called). 3837 * 3838 * The implementation may modify the contents of the reqs array, e.g. to merge 3839 * requests. However, the fields opaque and error are left unmodified as they 3840 * are used to signal failure for a single request to the caller. 3841 */ 3842 int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) 3843 { 3844 MultiwriteCB *mcb; 3845 int i; 3846 3847 /* don't submit writes if we don't have a medium */ 3848 if (bs->drv == NULL) { 3849 for (i = 0; i < num_reqs; i++) { 3850 reqs[i].error = -ENOMEDIUM; 3851 } 3852 return -1; 3853 } 3854 3855 if (num_reqs == 0) { 3856 return 0; 3857 } 3858 3859 // Create MultiwriteCB structure 3860 mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks)); 3861 mcb->num_requests = 0; 3862 mcb->num_callbacks = num_reqs; 3863 3864 for (i = 0; i < num_reqs; i++) { 3865 mcb->callbacks[i].cb = reqs[i].cb; 3866 mcb->callbacks[i].opaque = reqs[i].opaque; 3867 } 3868 3869 // Check for mergable requests 3870 num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb); 3871 3872 trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs); 3873 3874 /* Run the aio requests. */ 3875 mcb->num_requests = num_reqs; 3876 for (i = 0; i < num_reqs; i++) { 3877 bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov, 3878 reqs[i].nb_sectors, reqs[i].flags, 3879 multiwrite_cb, mcb, 3880 true); 3881 } 3882 3883 return 0; 3884 } 3885 3886 void bdrv_aio_cancel(BlockDriverAIOCB *acb) 3887 { 3888 acb->aiocb_info->cancel(acb); 3889 } 3890 3891 /**************************************************************/ 3892 /* async block device emulation */ 3893 3894 typedef struct BlockDriverAIOCBSync { 3895 BlockDriverAIOCB common; 3896 QEMUBH *bh; 3897 int ret; 3898 /* vector translation state */ 3899 QEMUIOVector *qiov; 3900 uint8_t *bounce; 3901 int is_write; 3902 } BlockDriverAIOCBSync; 3903 3904 static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb) 3905 { 3906 BlockDriverAIOCBSync *acb = 3907 container_of(blockacb, BlockDriverAIOCBSync, common); 3908 qemu_bh_delete(acb->bh); 3909 acb->bh = NULL; 3910 qemu_aio_release(acb); 3911 } 3912 3913 static const AIOCBInfo bdrv_em_aiocb_info = { 3914 .aiocb_size = sizeof(BlockDriverAIOCBSync), 3915 .cancel = bdrv_aio_cancel_em, 3916 }; 3917 3918 static void bdrv_aio_bh_cb(void *opaque) 3919 { 3920 BlockDriverAIOCBSync *acb = opaque; 3921 3922 if (!acb->is_write) 3923 qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size); 3924 qemu_vfree(acb->bounce); 3925 acb->common.cb(acb->common.opaque, acb->ret); 3926 qemu_bh_delete(acb->bh); 3927 acb->bh = NULL; 3928 qemu_aio_release(acb); 3929 } 3930 3931 static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs, 3932 int64_t sector_num, 3933 QEMUIOVector *qiov, 3934 int nb_sectors, 3935 BlockDriverCompletionFunc *cb, 3936 void *opaque, 3937 int is_write) 3938 3939 { 3940 BlockDriverAIOCBSync *acb; 3941 3942 acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque); 3943 acb->is_write = is_write; 3944 acb->qiov = qiov; 3945 acb->bounce = qemu_blockalign(bs, qiov->size); 3946 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb); 3947 3948 if (is_write) { 3949 qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); 3950 acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors); 3951 } else { 3952 acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors); 3953 } 3954 3955 qemu_bh_schedule(acb->bh); 3956 3957 return &acb->common; 3958 } 3959 3960 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, 3961 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 3962 BlockDriverCompletionFunc *cb, void *opaque) 3963 { 3964 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 3965 } 3966 3967 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, 3968 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 3969 BlockDriverCompletionFunc *cb, void *opaque) 3970 { 3971 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); 3972 } 3973 3974 3975 typedef struct BlockDriverAIOCBCoroutine { 3976 BlockDriverAIOCB common; 3977 BlockRequest req; 3978 bool is_write; 3979 bool *done; 3980 QEMUBH* bh; 3981 } BlockDriverAIOCBCoroutine; 3982 3983 static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb) 3984 { 3985 BlockDriverAIOCBCoroutine *acb = 3986 container_of(blockacb, BlockDriverAIOCBCoroutine, common); 3987 bool done = false; 3988 3989 acb->done = &done; 3990 while (!done) { 3991 qemu_aio_wait(); 3992 } 3993 } 3994 3995 static const AIOCBInfo bdrv_em_co_aiocb_info = { 3996 .aiocb_size = sizeof(BlockDriverAIOCBCoroutine), 3997 .cancel = bdrv_aio_co_cancel_em, 3998 }; 3999 4000 static void bdrv_co_em_bh(void *opaque) 4001 { 4002 BlockDriverAIOCBCoroutine *acb = opaque; 4003 4004 acb->common.cb(acb->common.opaque, acb->req.error); 4005 4006 if (acb->done) { 4007 *acb->done = true; 4008 } 4009 4010 qemu_bh_delete(acb->bh); 4011 qemu_aio_release(acb); 4012 } 4013 4014 /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ 4015 static void coroutine_fn bdrv_co_do_rw(void *opaque) 4016 { 4017 BlockDriverAIOCBCoroutine *acb = opaque; 4018 BlockDriverState *bs = acb->common.bs; 4019 4020 if (!acb->is_write) { 4021 acb->req.error = bdrv_co_do_readv(bs, acb->req.sector, 4022 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4023 } else { 4024 acb->req.error = bdrv_co_do_writev(bs, acb->req.sector, 4025 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4026 } 4027 4028 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4029 qemu_bh_schedule(acb->bh); 4030 } 4031 4032 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, 4033 int64_t sector_num, 4034 QEMUIOVector *qiov, 4035 int nb_sectors, 4036 BdrvRequestFlags flags, 4037 BlockDriverCompletionFunc *cb, 4038 void *opaque, 4039 bool is_write) 4040 { 4041 Coroutine *co; 4042 BlockDriverAIOCBCoroutine *acb; 4043 4044 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4045 acb->req.sector = sector_num; 4046 acb->req.nb_sectors = nb_sectors; 4047 acb->req.qiov = qiov; 4048 acb->req.flags = flags; 4049 acb->is_write = is_write; 4050 acb->done = NULL; 4051 4052 co = qemu_coroutine_create(bdrv_co_do_rw); 4053 qemu_coroutine_enter(co, acb); 4054 4055 return &acb->common; 4056 } 4057 4058 static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque) 4059 { 4060 BlockDriverAIOCBCoroutine *acb = opaque; 4061 BlockDriverState *bs = acb->common.bs; 4062 4063 acb->req.error = bdrv_co_flush(bs); 4064 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4065 qemu_bh_schedule(acb->bh); 4066 } 4067 4068 BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, 4069 BlockDriverCompletionFunc *cb, void *opaque) 4070 { 4071 trace_bdrv_aio_flush(bs, opaque); 4072 4073 Coroutine *co; 4074 BlockDriverAIOCBCoroutine *acb; 4075 4076 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4077 acb->done = NULL; 4078 4079 co = qemu_coroutine_create(bdrv_aio_flush_co_entry); 4080 qemu_coroutine_enter(co, acb); 4081 4082 return &acb->common; 4083 } 4084 4085 static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque) 4086 { 4087 BlockDriverAIOCBCoroutine *acb = opaque; 4088 BlockDriverState *bs = acb->common.bs; 4089 4090 acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors); 4091 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4092 qemu_bh_schedule(acb->bh); 4093 } 4094 4095 BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs, 4096 int64_t sector_num, int nb_sectors, 4097 BlockDriverCompletionFunc *cb, void *opaque) 4098 { 4099 Coroutine *co; 4100 BlockDriverAIOCBCoroutine *acb; 4101 4102 trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque); 4103 4104 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4105 acb->req.sector = sector_num; 4106 acb->req.nb_sectors = nb_sectors; 4107 acb->done = NULL; 4108 co = qemu_coroutine_create(bdrv_aio_discard_co_entry); 4109 qemu_coroutine_enter(co, acb); 4110 4111 return &acb->common; 4112 } 4113 4114 void bdrv_init(void) 4115 { 4116 module_call_init(MODULE_INIT_BLOCK); 4117 } 4118 4119 void bdrv_init_with_whitelist(void) 4120 { 4121 use_bdrv_whitelist = 1; 4122 bdrv_init(); 4123 } 4124 4125 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, 4126 BlockDriverCompletionFunc *cb, void *opaque) 4127 { 4128 BlockDriverAIOCB *acb; 4129 4130 acb = g_slice_alloc(aiocb_info->aiocb_size); 4131 acb->aiocb_info = aiocb_info; 4132 acb->bs = bs; 4133 acb->cb = cb; 4134 acb->opaque = opaque; 4135 return acb; 4136 } 4137 4138 void qemu_aio_release(void *p) 4139 { 4140 BlockDriverAIOCB *acb = p; 4141 g_slice_free1(acb->aiocb_info->aiocb_size, acb); 4142 } 4143 4144 /**************************************************************/ 4145 /* Coroutine block device emulation */ 4146 4147 typedef struct CoroutineIOCompletion { 4148 Coroutine *coroutine; 4149 int ret; 4150 } CoroutineIOCompletion; 4151 4152 static void bdrv_co_io_em_complete(void *opaque, int ret) 4153 { 4154 CoroutineIOCompletion *co = opaque; 4155 4156 co->ret = ret; 4157 qemu_coroutine_enter(co->coroutine, NULL); 4158 } 4159 4160 static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num, 4161 int nb_sectors, QEMUIOVector *iov, 4162 bool is_write) 4163 { 4164 CoroutineIOCompletion co = { 4165 .coroutine = qemu_coroutine_self(), 4166 }; 4167 BlockDriverAIOCB *acb; 4168 4169 if (is_write) { 4170 acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors, 4171 bdrv_co_io_em_complete, &co); 4172 } else { 4173 acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors, 4174 bdrv_co_io_em_complete, &co); 4175 } 4176 4177 trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb); 4178 if (!acb) { 4179 return -EIO; 4180 } 4181 qemu_coroutine_yield(); 4182 4183 return co.ret; 4184 } 4185 4186 static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, 4187 int64_t sector_num, int nb_sectors, 4188 QEMUIOVector *iov) 4189 { 4190 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false); 4191 } 4192 4193 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, 4194 int64_t sector_num, int nb_sectors, 4195 QEMUIOVector *iov) 4196 { 4197 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true); 4198 } 4199 4200 static void coroutine_fn bdrv_flush_co_entry(void *opaque) 4201 { 4202 RwCo *rwco = opaque; 4203 4204 rwco->ret = bdrv_co_flush(rwco->bs); 4205 } 4206 4207 int coroutine_fn bdrv_co_flush(BlockDriverState *bs) 4208 { 4209 int ret; 4210 4211 if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { 4212 return 0; 4213 } 4214 4215 /* Write back cached data to the OS even with cache=unsafe */ 4216 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); 4217 if (bs->drv->bdrv_co_flush_to_os) { 4218 ret = bs->drv->bdrv_co_flush_to_os(bs); 4219 if (ret < 0) { 4220 return ret; 4221 } 4222 } 4223 4224 /* But don't actually force it to the disk with cache=unsafe */ 4225 if (bs->open_flags & BDRV_O_NO_FLUSH) { 4226 goto flush_parent; 4227 } 4228 4229 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); 4230 if (bs->drv->bdrv_co_flush_to_disk) { 4231 ret = bs->drv->bdrv_co_flush_to_disk(bs); 4232 } else if (bs->drv->bdrv_aio_flush) { 4233 BlockDriverAIOCB *acb; 4234 CoroutineIOCompletion co = { 4235 .coroutine = qemu_coroutine_self(), 4236 }; 4237 4238 acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); 4239 if (acb == NULL) { 4240 ret = -EIO; 4241 } else { 4242 qemu_coroutine_yield(); 4243 ret = co.ret; 4244 } 4245 } else { 4246 /* 4247 * Some block drivers always operate in either writethrough or unsafe 4248 * mode and don't support bdrv_flush therefore. Usually qemu doesn't 4249 * know how the server works (because the behaviour is hardcoded or 4250 * depends on server-side configuration), so we can't ensure that 4251 * everything is safe on disk. Returning an error doesn't work because 4252 * that would break guests even if the server operates in writethrough 4253 * mode. 4254 * 4255 * Let's hope the user knows what he's doing. 4256 */ 4257 ret = 0; 4258 } 4259 if (ret < 0) { 4260 return ret; 4261 } 4262 4263 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH 4264 * in the case of cache=unsafe, so there are no useless flushes. 4265 */ 4266 flush_parent: 4267 return bdrv_co_flush(bs->file); 4268 } 4269 4270 void bdrv_invalidate_cache(BlockDriverState *bs) 4271 { 4272 if (bs->drv && bs->drv->bdrv_invalidate_cache) { 4273 bs->drv->bdrv_invalidate_cache(bs); 4274 } 4275 } 4276 4277 void bdrv_invalidate_cache_all(void) 4278 { 4279 BlockDriverState *bs; 4280 4281 QTAILQ_FOREACH(bs, &bdrv_states, list) { 4282 bdrv_invalidate_cache(bs); 4283 } 4284 } 4285 4286 void bdrv_clear_incoming_migration_all(void) 4287 { 4288 BlockDriverState *bs; 4289 4290 QTAILQ_FOREACH(bs, &bdrv_states, list) { 4291 bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING); 4292 } 4293 } 4294 4295 int bdrv_flush(BlockDriverState *bs) 4296 { 4297 Coroutine *co; 4298 RwCo rwco = { 4299 .bs = bs, 4300 .ret = NOT_DONE, 4301 }; 4302 4303 if (qemu_in_coroutine()) { 4304 /* Fast-path if already in coroutine context */ 4305 bdrv_flush_co_entry(&rwco); 4306 } else { 4307 co = qemu_coroutine_create(bdrv_flush_co_entry); 4308 qemu_coroutine_enter(co, &rwco); 4309 while (rwco.ret == NOT_DONE) { 4310 qemu_aio_wait(); 4311 } 4312 } 4313 4314 return rwco.ret; 4315 } 4316 4317 static void coroutine_fn bdrv_discard_co_entry(void *opaque) 4318 { 4319 RwCo *rwco = opaque; 4320 4321 rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); 4322 } 4323 4324 /* if no limit is specified in the BlockLimits use a default 4325 * of 32768 512-byte sectors (16 MiB) per request. 4326 */ 4327 #define MAX_DISCARD_DEFAULT 32768 4328 4329 int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, 4330 int nb_sectors) 4331 { 4332 int max_discard; 4333 4334 if (!bs->drv) { 4335 return -ENOMEDIUM; 4336 } else if (bdrv_check_request(bs, sector_num, nb_sectors)) { 4337 return -EIO; 4338 } else if (bs->read_only) { 4339 return -EROFS; 4340 } 4341 4342 bdrv_reset_dirty(bs, sector_num, nb_sectors); 4343 4344 /* Do nothing if disabled. */ 4345 if (!(bs->open_flags & BDRV_O_UNMAP)) { 4346 return 0; 4347 } 4348 4349 if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) { 4350 return 0; 4351 } 4352 4353 max_discard = bs->bl.max_discard ? bs->bl.max_discard : MAX_DISCARD_DEFAULT; 4354 while (nb_sectors > 0) { 4355 int ret; 4356 int num = nb_sectors; 4357 4358 /* align request */ 4359 if (bs->bl.discard_alignment && 4360 num >= bs->bl.discard_alignment && 4361 sector_num % bs->bl.discard_alignment) { 4362 if (num > bs->bl.discard_alignment) { 4363 num = bs->bl.discard_alignment; 4364 } 4365 num -= sector_num % bs->bl.discard_alignment; 4366 } 4367 4368 /* limit request size */ 4369 if (num > max_discard) { 4370 num = max_discard; 4371 } 4372 4373 if (bs->drv->bdrv_co_discard) { 4374 ret = bs->drv->bdrv_co_discard(bs, sector_num, num); 4375 } else { 4376 BlockDriverAIOCB *acb; 4377 CoroutineIOCompletion co = { 4378 .coroutine = qemu_coroutine_self(), 4379 }; 4380 4381 acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, 4382 bdrv_co_io_em_complete, &co); 4383 if (acb == NULL) { 4384 return -EIO; 4385 } else { 4386 qemu_coroutine_yield(); 4387 ret = co.ret; 4388 } 4389 } 4390 if (ret && ret != -ENOTSUP) { 4391 return ret; 4392 } 4393 4394 sector_num += num; 4395 nb_sectors -= num; 4396 } 4397 return 0; 4398 } 4399 4400 int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) 4401 { 4402 Coroutine *co; 4403 RwCo rwco = { 4404 .bs = bs, 4405 .sector_num = sector_num, 4406 .nb_sectors = nb_sectors, 4407 .ret = NOT_DONE, 4408 }; 4409 4410 if (qemu_in_coroutine()) { 4411 /* Fast-path if already in coroutine context */ 4412 bdrv_discard_co_entry(&rwco); 4413 } else { 4414 co = qemu_coroutine_create(bdrv_discard_co_entry); 4415 qemu_coroutine_enter(co, &rwco); 4416 while (rwco.ret == NOT_DONE) { 4417 qemu_aio_wait(); 4418 } 4419 } 4420 4421 return rwco.ret; 4422 } 4423 4424 /**************************************************************/ 4425 /* removable device support */ 4426 4427 /** 4428 * Return TRUE if the media is present 4429 */ 4430 int bdrv_is_inserted(BlockDriverState *bs) 4431 { 4432 BlockDriver *drv = bs->drv; 4433 4434 if (!drv) 4435 return 0; 4436 if (!drv->bdrv_is_inserted) 4437 return 1; 4438 return drv->bdrv_is_inserted(bs); 4439 } 4440 4441 /** 4442 * Return whether the media changed since the last call to this 4443 * function, or -ENOTSUP if we don't know. Most drivers don't know. 4444 */ 4445 int bdrv_media_changed(BlockDriverState *bs) 4446 { 4447 BlockDriver *drv = bs->drv; 4448 4449 if (drv && drv->bdrv_media_changed) { 4450 return drv->bdrv_media_changed(bs); 4451 } 4452 return -ENOTSUP; 4453 } 4454 4455 /** 4456 * If eject_flag is TRUE, eject the media. Otherwise, close the tray 4457 */ 4458 void bdrv_eject(BlockDriverState *bs, bool eject_flag) 4459 { 4460 BlockDriver *drv = bs->drv; 4461 4462 if (drv && drv->bdrv_eject) { 4463 drv->bdrv_eject(bs, eject_flag); 4464 } 4465 4466 if (bs->device_name[0] != '\0') { 4467 bdrv_emit_qmp_eject_event(bs, eject_flag); 4468 } 4469 } 4470 4471 /** 4472 * Lock or unlock the media (if it is locked, the user won't be able 4473 * to eject it manually). 4474 */ 4475 void bdrv_lock_medium(BlockDriverState *bs, bool locked) 4476 { 4477 BlockDriver *drv = bs->drv; 4478 4479 trace_bdrv_lock_medium(bs, locked); 4480 4481 if (drv && drv->bdrv_lock_medium) { 4482 drv->bdrv_lock_medium(bs, locked); 4483 } 4484 } 4485 4486 /* needed for generic scsi interface */ 4487 4488 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf) 4489 { 4490 BlockDriver *drv = bs->drv; 4491 4492 if (drv && drv->bdrv_ioctl) 4493 return drv->bdrv_ioctl(bs, req, buf); 4494 return -ENOTSUP; 4495 } 4496 4497 BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, 4498 unsigned long int req, void *buf, 4499 BlockDriverCompletionFunc *cb, void *opaque) 4500 { 4501 BlockDriver *drv = bs->drv; 4502 4503 if (drv && drv->bdrv_aio_ioctl) 4504 return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque); 4505 return NULL; 4506 } 4507 4508 void bdrv_set_buffer_alignment(BlockDriverState *bs, int align) 4509 { 4510 bs->buffer_alignment = align; 4511 } 4512 4513 void *qemu_blockalign(BlockDriverState *bs, size_t size) 4514 { 4515 return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size); 4516 } 4517 4518 /* 4519 * Check if all memory in this vector is sector aligned. 4520 */ 4521 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) 4522 { 4523 int i; 4524 4525 for (i = 0; i < qiov->niov; i++) { 4526 if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) { 4527 return false; 4528 } 4529 } 4530 4531 return true; 4532 } 4533 4534 BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity) 4535 { 4536 int64_t bitmap_size; 4537 BdrvDirtyBitmap *bitmap; 4538 4539 assert((granularity & (granularity - 1)) == 0); 4540 4541 granularity >>= BDRV_SECTOR_BITS; 4542 assert(granularity); 4543 bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS); 4544 bitmap = g_malloc0(sizeof(BdrvDirtyBitmap)); 4545 bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1); 4546 QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list); 4547 return bitmap; 4548 } 4549 4550 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 4551 { 4552 BdrvDirtyBitmap *bm, *next; 4553 QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { 4554 if (bm == bitmap) { 4555 QLIST_REMOVE(bitmap, list); 4556 hbitmap_free(bitmap->bitmap); 4557 g_free(bitmap); 4558 return; 4559 } 4560 } 4561 } 4562 4563 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs) 4564 { 4565 BdrvDirtyBitmap *bm; 4566 BlockDirtyInfoList *list = NULL; 4567 BlockDirtyInfoList **plist = &list; 4568 4569 QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { 4570 BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo)); 4571 BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList)); 4572 info->count = bdrv_get_dirty_count(bs, bm); 4573 info->granularity = 4574 ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap)); 4575 entry->value = info; 4576 *plist = entry; 4577 plist = &entry->next; 4578 } 4579 4580 return list; 4581 } 4582 4583 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector) 4584 { 4585 if (bitmap) { 4586 return hbitmap_get(bitmap->bitmap, sector); 4587 } else { 4588 return 0; 4589 } 4590 } 4591 4592 void bdrv_dirty_iter_init(BlockDriverState *bs, 4593 BdrvDirtyBitmap *bitmap, HBitmapIter *hbi) 4594 { 4595 hbitmap_iter_init(hbi, bitmap->bitmap, 0); 4596 } 4597 4598 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, 4599 int nr_sectors) 4600 { 4601 BdrvDirtyBitmap *bitmap; 4602 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 4603 hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); 4604 } 4605 } 4606 4607 void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) 4608 { 4609 BdrvDirtyBitmap *bitmap; 4610 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 4611 hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); 4612 } 4613 } 4614 4615 int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 4616 { 4617 return hbitmap_count(bitmap->bitmap); 4618 } 4619 4620 /* Get a reference to bs */ 4621 void bdrv_ref(BlockDriverState *bs) 4622 { 4623 bs->refcnt++; 4624 } 4625 4626 /* Release a previously grabbed reference to bs. 4627 * If after releasing, reference count is zero, the BlockDriverState is 4628 * deleted. */ 4629 void bdrv_unref(BlockDriverState *bs) 4630 { 4631 assert(bs->refcnt > 0); 4632 if (--bs->refcnt == 0) { 4633 bdrv_delete(bs); 4634 } 4635 } 4636 4637 void bdrv_set_in_use(BlockDriverState *bs, int in_use) 4638 { 4639 assert(bs->in_use != in_use); 4640 bs->in_use = in_use; 4641 } 4642 4643 int bdrv_in_use(BlockDriverState *bs) 4644 { 4645 return bs->in_use; 4646 } 4647 4648 void bdrv_iostatus_enable(BlockDriverState *bs) 4649 { 4650 bs->iostatus_enabled = true; 4651 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 4652 } 4653 4654 /* The I/O status is only enabled if the drive explicitly 4655 * enables it _and_ the VM is configured to stop on errors */ 4656 bool bdrv_iostatus_is_enabled(const BlockDriverState *bs) 4657 { 4658 return (bs->iostatus_enabled && 4659 (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC || 4660 bs->on_write_error == BLOCKDEV_ON_ERROR_STOP || 4661 bs->on_read_error == BLOCKDEV_ON_ERROR_STOP)); 4662 } 4663 4664 void bdrv_iostatus_disable(BlockDriverState *bs) 4665 { 4666 bs->iostatus_enabled = false; 4667 } 4668 4669 void bdrv_iostatus_reset(BlockDriverState *bs) 4670 { 4671 if (bdrv_iostatus_is_enabled(bs)) { 4672 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 4673 if (bs->job) { 4674 block_job_iostatus_reset(bs->job); 4675 } 4676 } 4677 } 4678 4679 void bdrv_iostatus_set_err(BlockDriverState *bs, int error) 4680 { 4681 assert(bdrv_iostatus_is_enabled(bs)); 4682 if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 4683 bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : 4684 BLOCK_DEVICE_IO_STATUS_FAILED; 4685 } 4686 } 4687 4688 void 4689 bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes, 4690 enum BlockAcctType type) 4691 { 4692 assert(type < BDRV_MAX_IOTYPE); 4693 4694 cookie->bytes = bytes; 4695 cookie->start_time_ns = get_clock(); 4696 cookie->type = type; 4697 } 4698 4699 void 4700 bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie) 4701 { 4702 assert(cookie->type < BDRV_MAX_IOTYPE); 4703 4704 bs->nr_bytes[cookie->type] += cookie->bytes; 4705 bs->nr_ops[cookie->type]++; 4706 bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns; 4707 } 4708 4709 void bdrv_img_create(const char *filename, const char *fmt, 4710 const char *base_filename, const char *base_fmt, 4711 char *options, uint64_t img_size, int flags, 4712 Error **errp, bool quiet) 4713 { 4714 QEMUOptionParameter *param = NULL, *create_options = NULL; 4715 QEMUOptionParameter *backing_fmt, *backing_file, *size; 4716 BlockDriver *drv, *proto_drv; 4717 BlockDriver *backing_drv = NULL; 4718 Error *local_err = NULL; 4719 int ret = 0; 4720 4721 /* Find driver and parse its options */ 4722 drv = bdrv_find_format(fmt); 4723 if (!drv) { 4724 error_setg(errp, "Unknown file format '%s'", fmt); 4725 return; 4726 } 4727 4728 proto_drv = bdrv_find_protocol(filename, true); 4729 if (!proto_drv) { 4730 error_setg(errp, "Unknown protocol '%s'", filename); 4731 return; 4732 } 4733 4734 create_options = append_option_parameters(create_options, 4735 drv->create_options); 4736 create_options = append_option_parameters(create_options, 4737 proto_drv->create_options); 4738 4739 /* Create parameter list with default values */ 4740 param = parse_option_parameters("", create_options, param); 4741 4742 set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size); 4743 4744 /* Parse -o options */ 4745 if (options) { 4746 param = parse_option_parameters(options, create_options, param); 4747 if (param == NULL) { 4748 error_setg(errp, "Invalid options for file format '%s'.", fmt); 4749 goto out; 4750 } 4751 } 4752 4753 if (base_filename) { 4754 if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE, 4755 base_filename)) { 4756 error_setg(errp, "Backing file not supported for file format '%s'", 4757 fmt); 4758 goto out; 4759 } 4760 } 4761 4762 if (base_fmt) { 4763 if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) { 4764 error_setg(errp, "Backing file format not supported for file " 4765 "format '%s'", fmt); 4766 goto out; 4767 } 4768 } 4769 4770 backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); 4771 if (backing_file && backing_file->value.s) { 4772 if (!strcmp(filename, backing_file->value.s)) { 4773 error_setg(errp, "Error: Trying to create an image with the " 4774 "same filename as the backing file"); 4775 goto out; 4776 } 4777 } 4778 4779 backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT); 4780 if (backing_fmt && backing_fmt->value.s) { 4781 backing_drv = bdrv_find_format(backing_fmt->value.s); 4782 if (!backing_drv) { 4783 error_setg(errp, "Unknown backing file format '%s'", 4784 backing_fmt->value.s); 4785 goto out; 4786 } 4787 } 4788 4789 // The size for the image must always be specified, with one exception: 4790 // If we are using a backing file, we can obtain the size from there 4791 size = get_option_parameter(param, BLOCK_OPT_SIZE); 4792 if (size && size->value.n == -1) { 4793 if (backing_file && backing_file->value.s) { 4794 BlockDriverState *bs; 4795 uint64_t size; 4796 char buf[32]; 4797 int back_flags; 4798 4799 /* backing files always opened read-only */ 4800 back_flags = 4801 flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 4802 4803 bs = bdrv_new(""); 4804 4805 ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags, 4806 backing_drv, &local_err); 4807 if (ret < 0) { 4808 error_setg_errno(errp, -ret, "Could not open '%s': %s", 4809 backing_file->value.s, 4810 error_get_pretty(local_err)); 4811 error_free(local_err); 4812 local_err = NULL; 4813 bdrv_unref(bs); 4814 goto out; 4815 } 4816 bdrv_get_geometry(bs, &size); 4817 size *= 512; 4818 4819 snprintf(buf, sizeof(buf), "%" PRId64, size); 4820 set_option_parameter(param, BLOCK_OPT_SIZE, buf); 4821 4822 bdrv_unref(bs); 4823 } else { 4824 error_setg(errp, "Image creation needs a size parameter"); 4825 goto out; 4826 } 4827 } 4828 4829 if (!quiet) { 4830 printf("Formatting '%s', fmt=%s ", filename, fmt); 4831 print_option_parameters(param); 4832 puts(""); 4833 } 4834 ret = bdrv_create(drv, filename, param, &local_err); 4835 if (ret == -EFBIG) { 4836 /* This is generally a better message than whatever the driver would 4837 * deliver (especially because of the cluster_size_hint), since that 4838 * is most probably not much different from "image too large". */ 4839 const char *cluster_size_hint = ""; 4840 if (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) { 4841 cluster_size_hint = " (try using a larger cluster size)"; 4842 } 4843 error_setg(errp, "The image size is too large for file format '%s'" 4844 "%s", fmt, cluster_size_hint); 4845 error_free(local_err); 4846 local_err = NULL; 4847 } 4848 4849 out: 4850 free_option_parameters(create_options); 4851 free_option_parameters(param); 4852 4853 if (error_is_set(&local_err)) { 4854 error_propagate(errp, local_err); 4855 } 4856 } 4857 4858 AioContext *bdrv_get_aio_context(BlockDriverState *bs) 4859 { 4860 /* Currently BlockDriverState always uses the main loop AioContext */ 4861 return qemu_get_aio_context(); 4862 } 4863 4864 void bdrv_add_before_write_notifier(BlockDriverState *bs, 4865 NotifierWithReturn *notifier) 4866 { 4867 notifier_with_return_list_add(&bs->before_write_notifiers, notifier); 4868 } 4869 4870 int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options) 4871 { 4872 if (bs->drv->bdrv_amend_options == NULL) { 4873 return -ENOTSUP; 4874 } 4875 return bs->drv->bdrv_amend_options(bs, options); 4876 } 4877 4878 ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs) 4879 { 4880 if (bs->drv->bdrv_check_ext_snapshot) { 4881 return bs->drv->bdrv_check_ext_snapshot(bs); 4882 } 4883 4884 if (bs->file && bs->file->drv && bs->file->drv->bdrv_check_ext_snapshot) { 4885 return bs->file->drv->bdrv_check_ext_snapshot(bs); 4886 } 4887 4888 /* external snapshots are allowed by default */ 4889 return EXT_SNAPSHOT_ALLOWED; 4890 } 4891 4892 ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs) 4893 { 4894 return EXT_SNAPSHOT_FORBIDDEN; 4895 } 4896