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 "block/qapi.h" 36 #include "qmp-commands.h" 37 #include "qemu/timer.h" 38 39 #ifdef CONFIG_BSD 40 #include <sys/types.h> 41 #include <sys/stat.h> 42 #include <sys/ioctl.h> 43 #include <sys/queue.h> 44 #ifndef __DragonFly__ 45 #include <sys/disk.h> 46 #endif 47 #endif 48 49 #ifdef _WIN32 50 #include <windows.h> 51 #endif 52 53 struct BdrvDirtyBitmap { 54 HBitmap *bitmap; 55 QLIST_ENTRY(BdrvDirtyBitmap) list; 56 }; 57 58 #define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */ 59 60 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load); 61 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, 62 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 63 BlockDriverCompletionFunc *cb, void *opaque); 64 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, 65 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 66 BlockDriverCompletionFunc *cb, void *opaque); 67 static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, 68 int64_t sector_num, int nb_sectors, 69 QEMUIOVector *iov); 70 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, 71 int64_t sector_num, int nb_sectors, 72 QEMUIOVector *iov); 73 static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, 74 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 75 BdrvRequestFlags flags); 76 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 77 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 78 BdrvRequestFlags flags); 79 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, 80 int64_t sector_num, 81 QEMUIOVector *qiov, 82 int nb_sectors, 83 BdrvRequestFlags flags, 84 BlockDriverCompletionFunc *cb, 85 void *opaque, 86 bool is_write); 87 static void coroutine_fn bdrv_co_do_rw(void *opaque); 88 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, 89 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags); 90 91 static QTAILQ_HEAD(, BlockDriverState) bdrv_states = 92 QTAILQ_HEAD_INITIALIZER(bdrv_states); 93 94 static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states = 95 QTAILQ_HEAD_INITIALIZER(graph_bdrv_states); 96 97 static QLIST_HEAD(, BlockDriver) bdrv_drivers = 98 QLIST_HEAD_INITIALIZER(bdrv_drivers); 99 100 /* If non-zero, use only whitelisted block drivers */ 101 static int use_bdrv_whitelist; 102 103 #ifdef _WIN32 104 static int is_windows_drive_prefix(const char *filename) 105 { 106 return (((filename[0] >= 'a' && filename[0] <= 'z') || 107 (filename[0] >= 'A' && filename[0] <= 'Z')) && 108 filename[1] == ':'); 109 } 110 111 int is_windows_drive(const char *filename) 112 { 113 if (is_windows_drive_prefix(filename) && 114 filename[2] == '\0') 115 return 1; 116 if (strstart(filename, "\\\\.\\", NULL) || 117 strstart(filename, "//./", NULL)) 118 return 1; 119 return 0; 120 } 121 #endif 122 123 /* throttling disk I/O limits */ 124 void bdrv_set_io_limits(BlockDriverState *bs, 125 ThrottleConfig *cfg) 126 { 127 int i; 128 129 throttle_config(&bs->throttle_state, cfg); 130 131 for (i = 0; i < 2; i++) { 132 qemu_co_enter_next(&bs->throttled_reqs[i]); 133 } 134 } 135 136 /* this function drain all the throttled IOs */ 137 static bool bdrv_start_throttled_reqs(BlockDriverState *bs) 138 { 139 bool drained = false; 140 bool enabled = bs->io_limits_enabled; 141 int i; 142 143 bs->io_limits_enabled = false; 144 145 for (i = 0; i < 2; i++) { 146 while (qemu_co_enter_next(&bs->throttled_reqs[i])) { 147 drained = true; 148 } 149 } 150 151 bs->io_limits_enabled = enabled; 152 153 return drained; 154 } 155 156 void bdrv_io_limits_disable(BlockDriverState *bs) 157 { 158 bs->io_limits_enabled = false; 159 160 bdrv_start_throttled_reqs(bs); 161 162 throttle_destroy(&bs->throttle_state); 163 } 164 165 static void bdrv_throttle_read_timer_cb(void *opaque) 166 { 167 BlockDriverState *bs = opaque; 168 qemu_co_enter_next(&bs->throttled_reqs[0]); 169 } 170 171 static void bdrv_throttle_write_timer_cb(void *opaque) 172 { 173 BlockDriverState *bs = opaque; 174 qemu_co_enter_next(&bs->throttled_reqs[1]); 175 } 176 177 /* should be called before bdrv_set_io_limits if a limit is set */ 178 void bdrv_io_limits_enable(BlockDriverState *bs) 179 { 180 assert(!bs->io_limits_enabled); 181 throttle_init(&bs->throttle_state, 182 QEMU_CLOCK_VIRTUAL, 183 bdrv_throttle_read_timer_cb, 184 bdrv_throttle_write_timer_cb, 185 bs); 186 bs->io_limits_enabled = true; 187 } 188 189 /* This function makes an IO wait if needed 190 * 191 * @nb_sectors: the number of sectors of the IO 192 * @is_write: is the IO a write 193 */ 194 static void bdrv_io_limits_intercept(BlockDriverState *bs, 195 int nb_sectors, 196 bool is_write) 197 { 198 /* does this io must wait */ 199 bool must_wait = throttle_schedule_timer(&bs->throttle_state, is_write); 200 201 /* if must wait or any request of this type throttled queue the IO */ 202 if (must_wait || 203 !qemu_co_queue_empty(&bs->throttled_reqs[is_write])) { 204 qemu_co_queue_wait(&bs->throttled_reqs[is_write]); 205 } 206 207 /* the IO will be executed, do the accounting */ 208 throttle_account(&bs->throttle_state, 209 is_write, 210 nb_sectors * BDRV_SECTOR_SIZE); 211 212 /* if the next request must wait -> do nothing */ 213 if (throttle_schedule_timer(&bs->throttle_state, is_write)) { 214 return; 215 } 216 217 /* else queue next request for execution */ 218 qemu_co_queue_next(&bs->throttled_reqs[is_write]); 219 } 220 221 /* check if the path starts with "<protocol>:" */ 222 static int path_has_protocol(const char *path) 223 { 224 const char *p; 225 226 #ifdef _WIN32 227 if (is_windows_drive(path) || 228 is_windows_drive_prefix(path)) { 229 return 0; 230 } 231 p = path + strcspn(path, ":/\\"); 232 #else 233 p = path + strcspn(path, ":/"); 234 #endif 235 236 return *p == ':'; 237 } 238 239 int path_is_absolute(const char *path) 240 { 241 #ifdef _WIN32 242 /* specific case for names like: "\\.\d:" */ 243 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { 244 return 1; 245 } 246 return (*path == '/' || *path == '\\'); 247 #else 248 return (*path == '/'); 249 #endif 250 } 251 252 /* if filename is absolute, just copy it to dest. Otherwise, build a 253 path to it by considering it is relative to base_path. URL are 254 supported. */ 255 void path_combine(char *dest, int dest_size, 256 const char *base_path, 257 const char *filename) 258 { 259 const char *p, *p1; 260 int len; 261 262 if (dest_size <= 0) 263 return; 264 if (path_is_absolute(filename)) { 265 pstrcpy(dest, dest_size, filename); 266 } else { 267 p = strchr(base_path, ':'); 268 if (p) 269 p++; 270 else 271 p = base_path; 272 p1 = strrchr(base_path, '/'); 273 #ifdef _WIN32 274 { 275 const char *p2; 276 p2 = strrchr(base_path, '\\'); 277 if (!p1 || p2 > p1) 278 p1 = p2; 279 } 280 #endif 281 if (p1) 282 p1++; 283 else 284 p1 = base_path; 285 if (p1 > p) 286 p = p1; 287 len = p - base_path; 288 if (len > dest_size - 1) 289 len = dest_size - 1; 290 memcpy(dest, base_path, len); 291 dest[len] = '\0'; 292 pstrcat(dest, dest_size, filename); 293 } 294 } 295 296 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz) 297 { 298 if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) { 299 pstrcpy(dest, sz, bs->backing_file); 300 } else { 301 path_combine(dest, sz, bs->filename, bs->backing_file); 302 } 303 } 304 305 void bdrv_register(BlockDriver *bdrv) 306 { 307 /* Block drivers without coroutine functions need emulation */ 308 if (!bdrv->bdrv_co_readv) { 309 bdrv->bdrv_co_readv = bdrv_co_readv_em; 310 bdrv->bdrv_co_writev = bdrv_co_writev_em; 311 312 /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if 313 * the block driver lacks aio we need to emulate that too. 314 */ 315 if (!bdrv->bdrv_aio_readv) { 316 /* add AIO emulation layer */ 317 bdrv->bdrv_aio_readv = bdrv_aio_readv_em; 318 bdrv->bdrv_aio_writev = bdrv_aio_writev_em; 319 } 320 } 321 322 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); 323 } 324 325 /* create a new block device (by default it is empty) */ 326 BlockDriverState *bdrv_new(const char *device_name) 327 { 328 BlockDriverState *bs; 329 330 bs = g_malloc0(sizeof(BlockDriverState)); 331 QLIST_INIT(&bs->dirty_bitmaps); 332 pstrcpy(bs->device_name, sizeof(bs->device_name), device_name); 333 if (device_name[0] != '\0') { 334 QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list); 335 } 336 bdrv_iostatus_disable(bs); 337 notifier_list_init(&bs->close_notifiers); 338 notifier_with_return_list_init(&bs->before_write_notifiers); 339 qemu_co_queue_init(&bs->throttled_reqs[0]); 340 qemu_co_queue_init(&bs->throttled_reqs[1]); 341 bs->refcnt = 1; 342 343 return bs; 344 } 345 346 void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify) 347 { 348 notifier_list_add(&bs->close_notifiers, notify); 349 } 350 351 BlockDriver *bdrv_find_format(const char *format_name) 352 { 353 BlockDriver *drv1; 354 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 355 if (!strcmp(drv1->format_name, format_name)) { 356 return drv1; 357 } 358 } 359 return NULL; 360 } 361 362 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) 363 { 364 static const char *whitelist_rw[] = { 365 CONFIG_BDRV_RW_WHITELIST 366 }; 367 static const char *whitelist_ro[] = { 368 CONFIG_BDRV_RO_WHITELIST 369 }; 370 const char **p; 371 372 if (!whitelist_rw[0] && !whitelist_ro[0]) { 373 return 1; /* no whitelist, anything goes */ 374 } 375 376 for (p = whitelist_rw; *p; p++) { 377 if (!strcmp(drv->format_name, *p)) { 378 return 1; 379 } 380 } 381 if (read_only) { 382 for (p = whitelist_ro; *p; p++) { 383 if (!strcmp(drv->format_name, *p)) { 384 return 1; 385 } 386 } 387 } 388 return 0; 389 } 390 391 BlockDriver *bdrv_find_whitelisted_format(const char *format_name, 392 bool read_only) 393 { 394 BlockDriver *drv = bdrv_find_format(format_name); 395 return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL; 396 } 397 398 typedef struct CreateCo { 399 BlockDriver *drv; 400 char *filename; 401 QEMUOptionParameter *options; 402 int ret; 403 Error *err; 404 } CreateCo; 405 406 static void coroutine_fn bdrv_create_co_entry(void *opaque) 407 { 408 Error *local_err = NULL; 409 int ret; 410 411 CreateCo *cco = opaque; 412 assert(cco->drv); 413 414 ret = cco->drv->bdrv_create(cco->filename, cco->options, &local_err); 415 if (error_is_set(&local_err)) { 416 error_propagate(&cco->err, local_err); 417 } 418 cco->ret = ret; 419 } 420 421 int bdrv_create(BlockDriver *drv, const char* filename, 422 QEMUOptionParameter *options, Error **errp) 423 { 424 int ret; 425 426 Coroutine *co; 427 CreateCo cco = { 428 .drv = drv, 429 .filename = g_strdup(filename), 430 .options = options, 431 .ret = NOT_DONE, 432 .err = NULL, 433 }; 434 435 if (!drv->bdrv_create) { 436 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); 437 ret = -ENOTSUP; 438 goto out; 439 } 440 441 if (qemu_in_coroutine()) { 442 /* Fast-path if already in coroutine context */ 443 bdrv_create_co_entry(&cco); 444 } else { 445 co = qemu_coroutine_create(bdrv_create_co_entry); 446 qemu_coroutine_enter(co, &cco); 447 while (cco.ret == NOT_DONE) { 448 qemu_aio_wait(); 449 } 450 } 451 452 ret = cco.ret; 453 if (ret < 0) { 454 if (error_is_set(&cco.err)) { 455 error_propagate(errp, cco.err); 456 } else { 457 error_setg_errno(errp, -ret, "Could not create image"); 458 } 459 } 460 461 out: 462 g_free(cco.filename); 463 return ret; 464 } 465 466 int bdrv_create_file(const char* filename, QEMUOptionParameter *options, 467 Error **errp) 468 { 469 BlockDriver *drv; 470 Error *local_err = NULL; 471 int ret; 472 473 drv = bdrv_find_protocol(filename, true); 474 if (drv == NULL) { 475 error_setg(errp, "Could not find protocol for file '%s'", filename); 476 return -ENOENT; 477 } 478 479 ret = bdrv_create(drv, filename, options, &local_err); 480 if (error_is_set(&local_err)) { 481 error_propagate(errp, local_err); 482 } 483 return ret; 484 } 485 486 static int bdrv_refresh_limits(BlockDriverState *bs) 487 { 488 BlockDriver *drv = bs->drv; 489 490 memset(&bs->bl, 0, sizeof(bs->bl)); 491 492 if (drv && drv->bdrv_refresh_limits) { 493 return drv->bdrv_refresh_limits(bs); 494 } 495 496 return 0; 497 } 498 499 /* 500 * Create a uniquely-named empty temporary file. 501 * Return 0 upon success, otherwise a negative errno value. 502 */ 503 int get_tmp_filename(char *filename, int size) 504 { 505 #ifdef _WIN32 506 char temp_dir[MAX_PATH]; 507 /* GetTempFileName requires that its output buffer (4th param) 508 have length MAX_PATH or greater. */ 509 assert(size >= MAX_PATH); 510 return (GetTempPath(MAX_PATH, temp_dir) 511 && GetTempFileName(temp_dir, "qem", 0, filename) 512 ? 0 : -GetLastError()); 513 #else 514 int fd; 515 const char *tmpdir; 516 tmpdir = getenv("TMPDIR"); 517 if (!tmpdir) 518 tmpdir = "/tmp"; 519 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { 520 return -EOVERFLOW; 521 } 522 fd = mkstemp(filename); 523 if (fd < 0) { 524 return -errno; 525 } 526 if (close(fd) != 0) { 527 unlink(filename); 528 return -errno; 529 } 530 return 0; 531 #endif 532 } 533 534 /* 535 * Detect host devices. By convention, /dev/cdrom[N] is always 536 * recognized as a host CDROM. 537 */ 538 static BlockDriver *find_hdev_driver(const char *filename) 539 { 540 int score_max = 0, score; 541 BlockDriver *drv = NULL, *d; 542 543 QLIST_FOREACH(d, &bdrv_drivers, list) { 544 if (d->bdrv_probe_device) { 545 score = d->bdrv_probe_device(filename); 546 if (score > score_max) { 547 score_max = score; 548 drv = d; 549 } 550 } 551 } 552 553 return drv; 554 } 555 556 BlockDriver *bdrv_find_protocol(const char *filename, 557 bool allow_protocol_prefix) 558 { 559 BlockDriver *drv1; 560 char protocol[128]; 561 int len; 562 const char *p; 563 564 /* TODO Drivers without bdrv_file_open must be specified explicitly */ 565 566 /* 567 * XXX(hch): we really should not let host device detection 568 * override an explicit protocol specification, but moving this 569 * later breaks access to device names with colons in them. 570 * Thanks to the brain-dead persistent naming schemes on udev- 571 * based Linux systems those actually are quite common. 572 */ 573 drv1 = find_hdev_driver(filename); 574 if (drv1) { 575 return drv1; 576 } 577 578 if (!path_has_protocol(filename) || !allow_protocol_prefix) { 579 return bdrv_find_format("file"); 580 } 581 582 p = strchr(filename, ':'); 583 assert(p != NULL); 584 len = p - filename; 585 if (len > sizeof(protocol) - 1) 586 len = sizeof(protocol) - 1; 587 memcpy(protocol, filename, len); 588 protocol[len] = '\0'; 589 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 590 if (drv1->protocol_name && 591 !strcmp(drv1->protocol_name, protocol)) { 592 return drv1; 593 } 594 } 595 return NULL; 596 } 597 598 static int find_image_format(BlockDriverState *bs, const char *filename, 599 BlockDriver **pdrv, Error **errp) 600 { 601 int score, score_max; 602 BlockDriver *drv1, *drv; 603 uint8_t buf[2048]; 604 int ret = 0; 605 606 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ 607 if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) { 608 drv = bdrv_find_format("raw"); 609 if (!drv) { 610 error_setg(errp, "Could not find raw image format"); 611 ret = -ENOENT; 612 } 613 *pdrv = drv; 614 return ret; 615 } 616 617 ret = bdrv_pread(bs, 0, buf, sizeof(buf)); 618 if (ret < 0) { 619 error_setg_errno(errp, -ret, "Could not read image for determining its " 620 "format"); 621 *pdrv = NULL; 622 return ret; 623 } 624 625 score_max = 0; 626 drv = NULL; 627 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 628 if (drv1->bdrv_probe) { 629 score = drv1->bdrv_probe(buf, ret, filename); 630 if (score > score_max) { 631 score_max = score; 632 drv = drv1; 633 } 634 } 635 } 636 if (!drv) { 637 error_setg(errp, "Could not determine image format: No compatible " 638 "driver found"); 639 ret = -ENOENT; 640 } 641 *pdrv = drv; 642 return ret; 643 } 644 645 /** 646 * Set the current 'total_sectors' value 647 */ 648 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint) 649 { 650 BlockDriver *drv = bs->drv; 651 652 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ 653 if (bs->sg) 654 return 0; 655 656 /* query actual device if possible, otherwise just trust the hint */ 657 if (drv->bdrv_getlength) { 658 int64_t length = drv->bdrv_getlength(bs); 659 if (length < 0) { 660 return length; 661 } 662 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); 663 } 664 665 bs->total_sectors = hint; 666 return 0; 667 } 668 669 /** 670 * Set open flags for a given discard mode 671 * 672 * Return 0 on success, -1 if the discard mode was invalid. 673 */ 674 int bdrv_parse_discard_flags(const char *mode, int *flags) 675 { 676 *flags &= ~BDRV_O_UNMAP; 677 678 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { 679 /* do nothing */ 680 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { 681 *flags |= BDRV_O_UNMAP; 682 } else { 683 return -1; 684 } 685 686 return 0; 687 } 688 689 /** 690 * Set open flags for a given cache mode 691 * 692 * Return 0 on success, -1 if the cache mode was invalid. 693 */ 694 int bdrv_parse_cache_flags(const char *mode, int *flags) 695 { 696 *flags &= ~BDRV_O_CACHE_MASK; 697 698 if (!strcmp(mode, "off") || !strcmp(mode, "none")) { 699 *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 700 } else if (!strcmp(mode, "directsync")) { 701 *flags |= BDRV_O_NOCACHE; 702 } else if (!strcmp(mode, "writeback")) { 703 *flags |= BDRV_O_CACHE_WB; 704 } else if (!strcmp(mode, "unsafe")) { 705 *flags |= BDRV_O_CACHE_WB; 706 *flags |= BDRV_O_NO_FLUSH; 707 } else if (!strcmp(mode, "writethrough")) { 708 /* this is the default */ 709 } else { 710 return -1; 711 } 712 713 return 0; 714 } 715 716 /** 717 * The copy-on-read flag is actually a reference count so multiple users may 718 * use the feature without worrying about clobbering its previous state. 719 * Copy-on-read stays enabled until all users have called to disable it. 720 */ 721 void bdrv_enable_copy_on_read(BlockDriverState *bs) 722 { 723 bs->copy_on_read++; 724 } 725 726 void bdrv_disable_copy_on_read(BlockDriverState *bs) 727 { 728 assert(bs->copy_on_read > 0); 729 bs->copy_on_read--; 730 } 731 732 static int bdrv_open_flags(BlockDriverState *bs, int flags) 733 { 734 int open_flags = flags | BDRV_O_CACHE_WB; 735 736 /* 737 * Clear flags that are internal to the block layer before opening the 738 * image. 739 */ 740 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 741 742 /* 743 * Snapshots should be writable. 744 */ 745 if (bs->is_temporary) { 746 open_flags |= BDRV_O_RDWR; 747 } 748 749 return open_flags; 750 } 751 752 static int bdrv_assign_node_name(BlockDriverState *bs, 753 const char *node_name, 754 Error **errp) 755 { 756 if (!node_name) { 757 return 0; 758 } 759 760 /* empty string node name is invalid */ 761 if (node_name[0] == '\0') { 762 error_setg(errp, "Empty node name"); 763 return -EINVAL; 764 } 765 766 /* takes care of avoiding duplicates node names */ 767 if (bdrv_find_node(node_name)) { 768 error_setg(errp, "Duplicate node name"); 769 return -EINVAL; 770 } 771 772 /* copy node name into the bs and insert it into the graph list */ 773 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name); 774 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list); 775 776 return 0; 777 } 778 779 /* 780 * Common part for opening disk images and files 781 * 782 * Removes all processed options from *options. 783 */ 784 static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file, 785 QDict *options, int flags, BlockDriver *drv, Error **errp) 786 { 787 int ret, open_flags; 788 const char *filename; 789 const char *node_name = NULL; 790 Error *local_err = NULL; 791 792 assert(drv != NULL); 793 assert(bs->file == NULL); 794 assert(options != NULL && bs->options != options); 795 796 if (file != NULL) { 797 filename = file->filename; 798 } else { 799 filename = qdict_get_try_str(options, "filename"); 800 } 801 802 trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name); 803 804 node_name = qdict_get_try_str(options, "node-name"); 805 ret = bdrv_assign_node_name(bs, node_name, errp); 806 if (ret < 0) { 807 return ret; 808 } 809 qdict_del(options, "node-name"); 810 811 /* bdrv_open() with directly using a protocol as drv. This layer is already 812 * opened, so assign it to bs (while file becomes a closed BlockDriverState) 813 * and return immediately. */ 814 if (file != NULL && drv->bdrv_file_open) { 815 bdrv_swap(file, bs); 816 return 0; 817 } 818 819 bs->open_flags = flags; 820 bs->buffer_alignment = 512; 821 bs->zero_beyond_eof = true; 822 open_flags = bdrv_open_flags(bs, flags); 823 bs->read_only = !(open_flags & BDRV_O_RDWR); 824 825 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { 826 error_setg(errp, 827 !bs->read_only && bdrv_is_whitelisted(drv, true) 828 ? "Driver '%s' can only be used for read-only devices" 829 : "Driver '%s' is not whitelisted", 830 drv->format_name); 831 return -ENOTSUP; 832 } 833 834 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */ 835 if (flags & BDRV_O_COPY_ON_READ) { 836 if (!bs->read_only) { 837 bdrv_enable_copy_on_read(bs); 838 } else { 839 error_setg(errp, "Can't use copy-on-read on read-only device"); 840 return -EINVAL; 841 } 842 } 843 844 if (filename != NULL) { 845 pstrcpy(bs->filename, sizeof(bs->filename), filename); 846 } else { 847 bs->filename[0] = '\0'; 848 } 849 850 bs->drv = drv; 851 bs->opaque = g_malloc0(drv->instance_size); 852 853 bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB); 854 855 /* Open the image, either directly or using a protocol */ 856 if (drv->bdrv_file_open) { 857 assert(file == NULL); 858 assert(!drv->bdrv_needs_filename || filename != NULL); 859 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); 860 } else { 861 if (file == NULL) { 862 error_setg(errp, "Can't use '%s' as a block driver for the " 863 "protocol level", drv->format_name); 864 ret = -EINVAL; 865 goto free_and_fail; 866 } 867 bs->file = file; 868 ret = drv->bdrv_open(bs, options, open_flags, &local_err); 869 } 870 871 if (ret < 0) { 872 if (error_is_set(&local_err)) { 873 error_propagate(errp, local_err); 874 } else if (bs->filename[0]) { 875 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); 876 } else { 877 error_setg_errno(errp, -ret, "Could not open image"); 878 } 879 goto free_and_fail; 880 } 881 882 ret = refresh_total_sectors(bs, bs->total_sectors); 883 if (ret < 0) { 884 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 885 goto free_and_fail; 886 } 887 888 bdrv_refresh_limits(bs); 889 890 #ifndef _WIN32 891 if (bs->is_temporary) { 892 assert(bs->filename[0] != '\0'); 893 unlink(bs->filename); 894 } 895 #endif 896 return 0; 897 898 free_and_fail: 899 bs->file = NULL; 900 g_free(bs->opaque); 901 bs->opaque = NULL; 902 bs->drv = NULL; 903 return ret; 904 } 905 906 /* 907 * Opens a file using a protocol (file, host_device, nbd, ...) 908 * 909 * options is a QDict of options to pass to the block drivers, or NULL for an 910 * empty set of options. The reference to the QDict belongs to the block layer 911 * after the call (even on failure), so if the caller intends to reuse the 912 * dictionary, it needs to use QINCREF() before calling bdrv_file_open. 913 */ 914 int bdrv_file_open(BlockDriverState **pbs, const char *filename, 915 const char *reference, QDict *options, int flags, 916 Error **errp) 917 { 918 BlockDriverState *bs = NULL; 919 BlockDriver *drv; 920 const char *drvname; 921 bool allow_protocol_prefix = false; 922 Error *local_err = NULL; 923 int ret; 924 925 /* NULL means an empty set of options */ 926 if (options == NULL) { 927 options = qdict_new(); 928 } 929 930 if (reference) { 931 if (filename || qdict_size(options)) { 932 error_setg(errp, "Cannot reference an existing block device with " 933 "additional options or a new filename"); 934 return -EINVAL; 935 } 936 QDECREF(options); 937 938 bs = bdrv_find(reference); 939 if (!bs) { 940 error_setg(errp, "Cannot find block device '%s'", reference); 941 return -ENODEV; 942 } 943 bdrv_ref(bs); 944 *pbs = bs; 945 return 0; 946 } 947 948 bs = bdrv_new(""); 949 bs->options = options; 950 options = qdict_clone_shallow(options); 951 952 /* Fetch the file name from the options QDict if necessary */ 953 if (!filename) { 954 filename = qdict_get_try_str(options, "filename"); 955 } else if (filename && !qdict_haskey(options, "filename")) { 956 qdict_put(options, "filename", qstring_from_str(filename)); 957 allow_protocol_prefix = true; 958 } else { 959 error_setg(errp, "Can't specify 'file' and 'filename' options at the " 960 "same time"); 961 ret = -EINVAL; 962 goto fail; 963 } 964 965 /* Find the right block driver */ 966 drvname = qdict_get_try_str(options, "driver"); 967 if (drvname) { 968 drv = bdrv_find_format(drvname); 969 if (!drv) { 970 error_setg(errp, "Unknown driver '%s'", drvname); 971 } 972 qdict_del(options, "driver"); 973 } else if (filename) { 974 drv = bdrv_find_protocol(filename, allow_protocol_prefix); 975 if (!drv) { 976 error_setg(errp, "Unknown protocol"); 977 } 978 } else { 979 error_setg(errp, "Must specify either driver or file"); 980 drv = NULL; 981 } 982 983 if (!drv) { 984 /* errp has been set already */ 985 ret = -ENOENT; 986 goto fail; 987 } 988 989 /* Parse the filename and open it */ 990 if (drv->bdrv_parse_filename && filename) { 991 drv->bdrv_parse_filename(filename, options, &local_err); 992 if (error_is_set(&local_err)) { 993 error_propagate(errp, local_err); 994 ret = -EINVAL; 995 goto fail; 996 } 997 qdict_del(options, "filename"); 998 } else if (drv->bdrv_needs_filename && !filename) { 999 error_setg(errp, "The '%s' block driver requires a file name", 1000 drv->format_name); 1001 ret = -EINVAL; 1002 goto fail; 1003 } 1004 1005 if (!drv->bdrv_file_open) { 1006 ret = bdrv_open(bs, filename, options, flags, drv, &local_err); 1007 options = NULL; 1008 } else { 1009 ret = bdrv_open_common(bs, NULL, options, flags, drv, &local_err); 1010 } 1011 if (ret < 0) { 1012 error_propagate(errp, local_err); 1013 goto fail; 1014 } 1015 1016 /* Check if any unknown options were used */ 1017 if (options && (qdict_size(options) != 0)) { 1018 const QDictEntry *entry = qdict_first(options); 1019 error_setg(errp, "Block protocol '%s' doesn't support the option '%s'", 1020 drv->format_name, entry->key); 1021 ret = -EINVAL; 1022 goto fail; 1023 } 1024 QDECREF(options); 1025 1026 bs->growable = 1; 1027 *pbs = bs; 1028 return 0; 1029 1030 fail: 1031 QDECREF(options); 1032 if (!bs->drv) { 1033 QDECREF(bs->options); 1034 } 1035 bdrv_unref(bs); 1036 return ret; 1037 } 1038 1039 /* 1040 * Opens the backing file for a BlockDriverState if not yet open 1041 * 1042 * options is a QDict of options to pass to the block drivers, or NULL for an 1043 * empty set of options. The reference to the QDict is transferred to this 1044 * function (even on failure), so if the caller intends to reuse the dictionary, 1045 * it needs to use QINCREF() before calling bdrv_file_open. 1046 */ 1047 int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) 1048 { 1049 char backing_filename[PATH_MAX]; 1050 int back_flags, ret; 1051 BlockDriver *back_drv = NULL; 1052 Error *local_err = NULL; 1053 1054 if (bs->backing_hd != NULL) { 1055 QDECREF(options); 1056 return 0; 1057 } 1058 1059 /* NULL means an empty set of options */ 1060 if (options == NULL) { 1061 options = qdict_new(); 1062 } 1063 1064 bs->open_flags &= ~BDRV_O_NO_BACKING; 1065 if (qdict_haskey(options, "file.filename")) { 1066 backing_filename[0] = '\0'; 1067 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { 1068 QDECREF(options); 1069 return 0; 1070 } else { 1071 bdrv_get_full_backing_filename(bs, backing_filename, 1072 sizeof(backing_filename)); 1073 } 1074 1075 bs->backing_hd = bdrv_new(""); 1076 1077 if (bs->backing_format[0] != '\0') { 1078 back_drv = bdrv_find_format(bs->backing_format); 1079 } 1080 1081 /* backing files always opened read-only */ 1082 back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | 1083 BDRV_O_COPY_ON_READ); 1084 1085 ret = bdrv_open(bs->backing_hd, 1086 *backing_filename ? backing_filename : NULL, options, 1087 back_flags, back_drv, &local_err); 1088 if (ret < 0) { 1089 bdrv_unref(bs->backing_hd); 1090 bs->backing_hd = NULL; 1091 bs->open_flags |= BDRV_O_NO_BACKING; 1092 error_setg(errp, "Could not open backing file: %s", 1093 error_get_pretty(local_err)); 1094 error_free(local_err); 1095 return ret; 1096 } 1097 1098 if (bs->backing_hd->file) { 1099 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1100 bs->backing_hd->file->filename); 1101 } 1102 1103 /* Recalculate the BlockLimits with the backing file */ 1104 bdrv_refresh_limits(bs); 1105 1106 return 0; 1107 } 1108 1109 /* 1110 * Opens a disk image whose options are given as BlockdevRef in another block 1111 * device's options. 1112 * 1113 * If force_raw is true, bdrv_file_open() will be used, thereby preventing any 1114 * image format auto-detection. If it is false and a filename is given, 1115 * bdrv_open() will be used for auto-detection. 1116 * 1117 * If allow_none is true, no image will be opened if filename is false and no 1118 * BlockdevRef is given. *pbs will remain unchanged and 0 will be returned. 1119 * 1120 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict. 1121 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict 1122 * itself, all options starting with "${bdref_key}." are considered part of the 1123 * BlockdevRef. 1124 * 1125 * The BlockdevRef will be removed from the options QDict. 1126 */ 1127 int bdrv_open_image(BlockDriverState **pbs, const char *filename, 1128 QDict *options, const char *bdref_key, int flags, 1129 bool force_raw, bool allow_none, Error **errp) 1130 { 1131 QDict *image_options; 1132 int ret; 1133 char *bdref_key_dot; 1134 const char *reference; 1135 1136 bdref_key_dot = g_strdup_printf("%s.", bdref_key); 1137 qdict_extract_subqdict(options, &image_options, bdref_key_dot); 1138 g_free(bdref_key_dot); 1139 1140 reference = qdict_get_try_str(options, bdref_key); 1141 if (!filename && !reference && !qdict_size(image_options)) { 1142 if (allow_none) { 1143 ret = 0; 1144 } else { 1145 error_setg(errp, "A block device must be specified for \"%s\"", 1146 bdref_key); 1147 ret = -EINVAL; 1148 } 1149 goto done; 1150 } 1151 1152 if (filename && !force_raw) { 1153 /* If a filename is given and the block driver should be detected 1154 automatically (instead of using none), use bdrv_open() in order to do 1155 that auto-detection. */ 1156 BlockDriverState *bs; 1157 1158 if (reference) { 1159 error_setg(errp, "Cannot reference an existing block device while " 1160 "giving a filename"); 1161 ret = -EINVAL; 1162 goto done; 1163 } 1164 1165 bs = bdrv_new(""); 1166 ret = bdrv_open(bs, filename, image_options, flags, NULL, errp); 1167 if (ret < 0) { 1168 bdrv_unref(bs); 1169 } else { 1170 *pbs = bs; 1171 } 1172 } else { 1173 ret = bdrv_file_open(pbs, filename, reference, image_options, flags, 1174 errp); 1175 } 1176 1177 done: 1178 qdict_del(options, bdref_key); 1179 return ret; 1180 } 1181 1182 /* 1183 * Opens a disk image (raw, qcow2, vmdk, ...) 1184 * 1185 * options is a QDict of options to pass to the block drivers, or NULL for an 1186 * empty set of options. The reference to the QDict belongs to the block layer 1187 * after the call (even on failure), so if the caller intends to reuse the 1188 * dictionary, it needs to use QINCREF() before calling bdrv_open. 1189 */ 1190 int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options, 1191 int flags, BlockDriver *drv, Error **errp) 1192 { 1193 int ret; 1194 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ 1195 char tmp_filename[PATH_MAX + 1]; 1196 BlockDriverState *file = NULL; 1197 const char *drvname; 1198 Error *local_err = NULL; 1199 1200 /* NULL means an empty set of options */ 1201 if (options == NULL) { 1202 options = qdict_new(); 1203 } 1204 1205 bs->options = options; 1206 options = qdict_clone_shallow(options); 1207 1208 /* For snapshot=on, create a temporary qcow2 overlay */ 1209 if (flags & BDRV_O_SNAPSHOT) { 1210 BlockDriverState *bs1; 1211 int64_t total_size; 1212 BlockDriver *bdrv_qcow2; 1213 QEMUOptionParameter *create_options; 1214 QDict *snapshot_options; 1215 1216 /* if snapshot, we create a temporary backing file and open it 1217 instead of opening 'filename' directly */ 1218 1219 /* Get the required size from the image */ 1220 bs1 = bdrv_new(""); 1221 QINCREF(options); 1222 ret = bdrv_open(bs1, filename, options, BDRV_O_NO_BACKING, 1223 drv, &local_err); 1224 if (ret < 0) { 1225 bdrv_unref(bs1); 1226 goto fail; 1227 } 1228 total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK; 1229 1230 bdrv_unref(bs1); 1231 1232 /* Create the temporary image */ 1233 ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename)); 1234 if (ret < 0) { 1235 error_setg_errno(errp, -ret, "Could not get temporary filename"); 1236 goto fail; 1237 } 1238 1239 bdrv_qcow2 = bdrv_find_format("qcow2"); 1240 create_options = parse_option_parameters("", bdrv_qcow2->create_options, 1241 NULL); 1242 1243 set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size); 1244 1245 ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err); 1246 free_option_parameters(create_options); 1247 if (ret < 0) { 1248 error_setg_errno(errp, -ret, "Could not create temporary overlay " 1249 "'%s': %s", tmp_filename, 1250 error_get_pretty(local_err)); 1251 error_free(local_err); 1252 local_err = NULL; 1253 goto fail; 1254 } 1255 1256 /* Prepare a new options QDict for the temporary file, where user 1257 * options refer to the backing file */ 1258 if (filename) { 1259 qdict_put(options, "file.filename", qstring_from_str(filename)); 1260 } 1261 if (drv) { 1262 qdict_put(options, "driver", qstring_from_str(drv->format_name)); 1263 } 1264 1265 snapshot_options = qdict_new(); 1266 qdict_put(snapshot_options, "backing", options); 1267 qdict_flatten(snapshot_options); 1268 1269 bs->options = snapshot_options; 1270 options = qdict_clone_shallow(bs->options); 1271 1272 filename = tmp_filename; 1273 drv = bdrv_qcow2; 1274 bs->is_temporary = 1; 1275 } 1276 1277 /* Open image file without format layer */ 1278 if (flags & BDRV_O_RDWR) { 1279 flags |= BDRV_O_ALLOW_RDWR; 1280 } 1281 1282 ret = bdrv_open_image(&file, filename, options, "file", 1283 bdrv_open_flags(bs, flags | BDRV_O_UNMAP), true, true, 1284 &local_err); 1285 if (ret < 0) { 1286 goto fail; 1287 } 1288 1289 /* Find the right image format driver */ 1290 drvname = qdict_get_try_str(options, "driver"); 1291 if (drvname) { 1292 drv = bdrv_find_format(drvname); 1293 qdict_del(options, "driver"); 1294 if (!drv) { 1295 error_setg(errp, "Invalid driver: '%s'", drvname); 1296 ret = -EINVAL; 1297 goto unlink_and_fail; 1298 } 1299 } 1300 1301 if (!drv) { 1302 if (file) { 1303 ret = find_image_format(file, filename, &drv, &local_err); 1304 } else { 1305 error_setg(errp, "Must specify either driver or file"); 1306 ret = -EINVAL; 1307 goto unlink_and_fail; 1308 } 1309 } 1310 1311 if (!drv) { 1312 goto unlink_and_fail; 1313 } 1314 1315 /* Open the image */ 1316 ret = bdrv_open_common(bs, file, options, flags, drv, &local_err); 1317 if (ret < 0) { 1318 goto unlink_and_fail; 1319 } 1320 1321 if (file && (bs->file != file)) { 1322 bdrv_unref(file); 1323 file = NULL; 1324 } 1325 1326 /* If there is a backing file, use it */ 1327 if ((flags & BDRV_O_NO_BACKING) == 0) { 1328 QDict *backing_options; 1329 1330 qdict_extract_subqdict(options, &backing_options, "backing."); 1331 ret = bdrv_open_backing_file(bs, backing_options, &local_err); 1332 if (ret < 0) { 1333 goto close_and_fail; 1334 } 1335 } 1336 1337 /* Check if any unknown options were used */ 1338 if (qdict_size(options) != 0) { 1339 const QDictEntry *entry = qdict_first(options); 1340 error_setg(errp, "Block format '%s' used by device '%s' doesn't " 1341 "support the option '%s'", drv->format_name, bs->device_name, 1342 entry->key); 1343 1344 ret = -EINVAL; 1345 goto close_and_fail; 1346 } 1347 QDECREF(options); 1348 1349 if (!bdrv_key_required(bs)) { 1350 bdrv_dev_change_media_cb(bs, true); 1351 } 1352 1353 return 0; 1354 1355 unlink_and_fail: 1356 if (file != NULL) { 1357 bdrv_unref(file); 1358 } 1359 if (bs->is_temporary) { 1360 unlink(filename); 1361 } 1362 fail: 1363 QDECREF(bs->options); 1364 QDECREF(options); 1365 bs->options = NULL; 1366 if (error_is_set(&local_err)) { 1367 error_propagate(errp, local_err); 1368 } 1369 return ret; 1370 1371 close_and_fail: 1372 bdrv_close(bs); 1373 QDECREF(options); 1374 if (error_is_set(&local_err)) { 1375 error_propagate(errp, local_err); 1376 } 1377 return ret; 1378 } 1379 1380 typedef struct BlockReopenQueueEntry { 1381 bool prepared; 1382 BDRVReopenState state; 1383 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; 1384 } BlockReopenQueueEntry; 1385 1386 /* 1387 * Adds a BlockDriverState to a simple queue for an atomic, transactional 1388 * reopen of multiple devices. 1389 * 1390 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT 1391 * already performed, or alternatively may be NULL a new BlockReopenQueue will 1392 * be created and initialized. This newly created BlockReopenQueue should be 1393 * passed back in for subsequent calls that are intended to be of the same 1394 * atomic 'set'. 1395 * 1396 * bs is the BlockDriverState to add to the reopen queue. 1397 * 1398 * flags contains the open flags for the associated bs 1399 * 1400 * returns a pointer to bs_queue, which is either the newly allocated 1401 * bs_queue, or the existing bs_queue being used. 1402 * 1403 */ 1404 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, 1405 BlockDriverState *bs, int flags) 1406 { 1407 assert(bs != NULL); 1408 1409 BlockReopenQueueEntry *bs_entry; 1410 if (bs_queue == NULL) { 1411 bs_queue = g_new0(BlockReopenQueue, 1); 1412 QSIMPLEQ_INIT(bs_queue); 1413 } 1414 1415 if (bs->file) { 1416 bdrv_reopen_queue(bs_queue, bs->file, flags); 1417 } 1418 1419 bs_entry = g_new0(BlockReopenQueueEntry, 1); 1420 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); 1421 1422 bs_entry->state.bs = bs; 1423 bs_entry->state.flags = flags; 1424 1425 return bs_queue; 1426 } 1427 1428 /* 1429 * Reopen multiple BlockDriverStates atomically & transactionally. 1430 * 1431 * The queue passed in (bs_queue) must have been built up previous 1432 * via bdrv_reopen_queue(). 1433 * 1434 * Reopens all BDS specified in the queue, with the appropriate 1435 * flags. All devices are prepared for reopen, and failure of any 1436 * device will cause all device changes to be abandonded, and intermediate 1437 * data cleaned up. 1438 * 1439 * If all devices prepare successfully, then the changes are committed 1440 * to all devices. 1441 * 1442 */ 1443 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) 1444 { 1445 int ret = -1; 1446 BlockReopenQueueEntry *bs_entry, *next; 1447 Error *local_err = NULL; 1448 1449 assert(bs_queue != NULL); 1450 1451 bdrv_drain_all(); 1452 1453 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 1454 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { 1455 error_propagate(errp, local_err); 1456 goto cleanup; 1457 } 1458 bs_entry->prepared = true; 1459 } 1460 1461 /* If we reach this point, we have success and just need to apply the 1462 * changes 1463 */ 1464 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 1465 bdrv_reopen_commit(&bs_entry->state); 1466 } 1467 1468 ret = 0; 1469 1470 cleanup: 1471 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { 1472 if (ret && bs_entry->prepared) { 1473 bdrv_reopen_abort(&bs_entry->state); 1474 } 1475 g_free(bs_entry); 1476 } 1477 g_free(bs_queue); 1478 return ret; 1479 } 1480 1481 1482 /* Reopen a single BlockDriverState with the specified flags. */ 1483 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) 1484 { 1485 int ret = -1; 1486 Error *local_err = NULL; 1487 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, bdrv_flags); 1488 1489 ret = bdrv_reopen_multiple(queue, &local_err); 1490 if (local_err != NULL) { 1491 error_propagate(errp, local_err); 1492 } 1493 return ret; 1494 } 1495 1496 1497 /* 1498 * Prepares a BlockDriverState for reopen. All changes are staged in the 1499 * 'opaque' field of the BDRVReopenState, which is used and allocated by 1500 * the block driver layer .bdrv_reopen_prepare() 1501 * 1502 * bs is the BlockDriverState to reopen 1503 * flags are the new open flags 1504 * queue is the reopen queue 1505 * 1506 * Returns 0 on success, non-zero on error. On error errp will be set 1507 * as well. 1508 * 1509 * On failure, bdrv_reopen_abort() will be called to clean up any data. 1510 * It is the responsibility of the caller to then call the abort() or 1511 * commit() for any other BDS that have been left in a prepare() state 1512 * 1513 */ 1514 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 1515 Error **errp) 1516 { 1517 int ret = -1; 1518 Error *local_err = NULL; 1519 BlockDriver *drv; 1520 1521 assert(reopen_state != NULL); 1522 assert(reopen_state->bs->drv != NULL); 1523 drv = reopen_state->bs->drv; 1524 1525 /* if we are to stay read-only, do not allow permission change 1526 * to r/w */ 1527 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) && 1528 reopen_state->flags & BDRV_O_RDWR) { 1529 error_set(errp, QERR_DEVICE_IS_READ_ONLY, 1530 reopen_state->bs->device_name); 1531 goto error; 1532 } 1533 1534 1535 ret = bdrv_flush(reopen_state->bs); 1536 if (ret) { 1537 error_set(errp, ERROR_CLASS_GENERIC_ERROR, "Error (%s) flushing drive", 1538 strerror(-ret)); 1539 goto error; 1540 } 1541 1542 if (drv->bdrv_reopen_prepare) { 1543 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); 1544 if (ret) { 1545 if (local_err != NULL) { 1546 error_propagate(errp, local_err); 1547 } else { 1548 error_setg(errp, "failed while preparing to reopen image '%s'", 1549 reopen_state->bs->filename); 1550 } 1551 goto error; 1552 } 1553 } else { 1554 /* It is currently mandatory to have a bdrv_reopen_prepare() 1555 * handler for each supported drv. */ 1556 error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 1557 drv->format_name, reopen_state->bs->device_name, 1558 "reopening of file"); 1559 ret = -1; 1560 goto error; 1561 } 1562 1563 ret = 0; 1564 1565 error: 1566 return ret; 1567 } 1568 1569 /* 1570 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and 1571 * makes them final by swapping the staging BlockDriverState contents into 1572 * the active BlockDriverState contents. 1573 */ 1574 void bdrv_reopen_commit(BDRVReopenState *reopen_state) 1575 { 1576 BlockDriver *drv; 1577 1578 assert(reopen_state != NULL); 1579 drv = reopen_state->bs->drv; 1580 assert(drv != NULL); 1581 1582 /* If there are any driver level actions to take */ 1583 if (drv->bdrv_reopen_commit) { 1584 drv->bdrv_reopen_commit(reopen_state); 1585 } 1586 1587 /* set BDS specific flags now */ 1588 reopen_state->bs->open_flags = reopen_state->flags; 1589 reopen_state->bs->enable_write_cache = !!(reopen_state->flags & 1590 BDRV_O_CACHE_WB); 1591 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); 1592 } 1593 1594 /* 1595 * Abort the reopen, and delete and free the staged changes in 1596 * reopen_state 1597 */ 1598 void bdrv_reopen_abort(BDRVReopenState *reopen_state) 1599 { 1600 BlockDriver *drv; 1601 1602 assert(reopen_state != NULL); 1603 drv = reopen_state->bs->drv; 1604 assert(drv != NULL); 1605 1606 if (drv->bdrv_reopen_abort) { 1607 drv->bdrv_reopen_abort(reopen_state); 1608 } 1609 } 1610 1611 1612 void bdrv_close(BlockDriverState *bs) 1613 { 1614 if (bs->job) { 1615 block_job_cancel_sync(bs->job); 1616 } 1617 bdrv_drain_all(); /* complete I/O */ 1618 bdrv_flush(bs); 1619 bdrv_drain_all(); /* in case flush left pending I/O */ 1620 notifier_list_notify(&bs->close_notifiers, bs); 1621 1622 if (bs->drv) { 1623 if (bs->backing_hd) { 1624 bdrv_unref(bs->backing_hd); 1625 bs->backing_hd = NULL; 1626 } 1627 bs->drv->bdrv_close(bs); 1628 g_free(bs->opaque); 1629 #ifdef _WIN32 1630 if (bs->is_temporary) { 1631 unlink(bs->filename); 1632 } 1633 #endif 1634 bs->opaque = NULL; 1635 bs->drv = NULL; 1636 bs->copy_on_read = 0; 1637 bs->backing_file[0] = '\0'; 1638 bs->backing_format[0] = '\0'; 1639 bs->total_sectors = 0; 1640 bs->encrypted = 0; 1641 bs->valid_key = 0; 1642 bs->sg = 0; 1643 bs->growable = 0; 1644 bs->zero_beyond_eof = false; 1645 QDECREF(bs->options); 1646 bs->options = NULL; 1647 1648 if (bs->file != NULL) { 1649 bdrv_unref(bs->file); 1650 bs->file = NULL; 1651 } 1652 } 1653 1654 bdrv_dev_change_media_cb(bs, false); 1655 1656 /*throttling disk I/O limits*/ 1657 if (bs->io_limits_enabled) { 1658 bdrv_io_limits_disable(bs); 1659 } 1660 } 1661 1662 void bdrv_close_all(void) 1663 { 1664 BlockDriverState *bs; 1665 1666 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 1667 bdrv_close(bs); 1668 } 1669 } 1670 1671 /* Check if any requests are in-flight (including throttled requests) */ 1672 static bool bdrv_requests_pending(BlockDriverState *bs) 1673 { 1674 if (!QLIST_EMPTY(&bs->tracked_requests)) { 1675 return true; 1676 } 1677 if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) { 1678 return true; 1679 } 1680 if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) { 1681 return true; 1682 } 1683 if (bs->file && bdrv_requests_pending(bs->file)) { 1684 return true; 1685 } 1686 if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) { 1687 return true; 1688 } 1689 return false; 1690 } 1691 1692 static bool bdrv_requests_pending_all(void) 1693 { 1694 BlockDriverState *bs; 1695 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 1696 if (bdrv_requests_pending(bs)) { 1697 return true; 1698 } 1699 } 1700 return false; 1701 } 1702 1703 /* 1704 * Wait for pending requests to complete across all BlockDriverStates 1705 * 1706 * This function does not flush data to disk, use bdrv_flush_all() for that 1707 * after calling this function. 1708 * 1709 * Note that completion of an asynchronous I/O operation can trigger any 1710 * number of other I/O operations on other devices---for example a coroutine 1711 * can be arbitrarily complex and a constant flow of I/O can come until the 1712 * coroutine is complete. Because of this, it is not possible to have a 1713 * function to drain a single device's I/O queue. 1714 */ 1715 void bdrv_drain_all(void) 1716 { 1717 /* Always run first iteration so any pending completion BHs run */ 1718 bool busy = true; 1719 BlockDriverState *bs; 1720 1721 while (busy) { 1722 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 1723 bdrv_start_throttled_reqs(bs); 1724 } 1725 1726 busy = bdrv_requests_pending_all(); 1727 busy |= aio_poll(qemu_get_aio_context(), busy); 1728 } 1729 } 1730 1731 /* make a BlockDriverState anonymous by removing from bdrv_state and 1732 * graph_bdrv_state list. 1733 Also, NULL terminate the device_name to prevent double remove */ 1734 void bdrv_make_anon(BlockDriverState *bs) 1735 { 1736 if (bs->device_name[0] != '\0') { 1737 QTAILQ_REMOVE(&bdrv_states, bs, device_list); 1738 } 1739 bs->device_name[0] = '\0'; 1740 if (bs->node_name[0] != '\0') { 1741 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); 1742 } 1743 bs->node_name[0] = '\0'; 1744 } 1745 1746 static void bdrv_rebind(BlockDriverState *bs) 1747 { 1748 if (bs->drv && bs->drv->bdrv_rebind) { 1749 bs->drv->bdrv_rebind(bs); 1750 } 1751 } 1752 1753 static void bdrv_move_feature_fields(BlockDriverState *bs_dest, 1754 BlockDriverState *bs_src) 1755 { 1756 /* move some fields that need to stay attached to the device */ 1757 bs_dest->open_flags = bs_src->open_flags; 1758 1759 /* dev info */ 1760 bs_dest->dev_ops = bs_src->dev_ops; 1761 bs_dest->dev_opaque = bs_src->dev_opaque; 1762 bs_dest->dev = bs_src->dev; 1763 bs_dest->buffer_alignment = bs_src->buffer_alignment; 1764 bs_dest->copy_on_read = bs_src->copy_on_read; 1765 1766 bs_dest->enable_write_cache = bs_src->enable_write_cache; 1767 1768 /* i/o throttled req */ 1769 memcpy(&bs_dest->throttle_state, 1770 &bs_src->throttle_state, 1771 sizeof(ThrottleState)); 1772 bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; 1773 bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; 1774 bs_dest->io_limits_enabled = bs_src->io_limits_enabled; 1775 1776 /* r/w error */ 1777 bs_dest->on_read_error = bs_src->on_read_error; 1778 bs_dest->on_write_error = bs_src->on_write_error; 1779 1780 /* i/o status */ 1781 bs_dest->iostatus_enabled = bs_src->iostatus_enabled; 1782 bs_dest->iostatus = bs_src->iostatus; 1783 1784 /* dirty bitmap */ 1785 bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps; 1786 1787 /* reference count */ 1788 bs_dest->refcnt = bs_src->refcnt; 1789 1790 /* job */ 1791 bs_dest->in_use = bs_src->in_use; 1792 bs_dest->job = bs_src->job; 1793 1794 /* keep the same entry in bdrv_states */ 1795 pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name), 1796 bs_src->device_name); 1797 bs_dest->device_list = bs_src->device_list; 1798 1799 /* keep the same entry in graph_bdrv_states 1800 * We do want to swap name but don't want to swap linked list entries 1801 */ 1802 bs_dest->node_list = bs_src->node_list; 1803 } 1804 1805 /* 1806 * Swap bs contents for two image chains while they are live, 1807 * while keeping required fields on the BlockDriverState that is 1808 * actually attached to a device. 1809 * 1810 * This will modify the BlockDriverState fields, and swap contents 1811 * between bs_new and bs_old. Both bs_new and bs_old are modified. 1812 * 1813 * bs_new is required to be anonymous. 1814 * 1815 * This function does not create any image files. 1816 */ 1817 void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) 1818 { 1819 BlockDriverState tmp; 1820 1821 /* bs_new must be anonymous and shouldn't have anything fancy enabled */ 1822 assert(bs_new->device_name[0] == '\0'); 1823 assert(QLIST_EMPTY(&bs_new->dirty_bitmaps)); 1824 assert(bs_new->job == NULL); 1825 assert(bs_new->dev == NULL); 1826 assert(bs_new->in_use == 0); 1827 assert(bs_new->io_limits_enabled == false); 1828 assert(!throttle_have_timer(&bs_new->throttle_state)); 1829 1830 tmp = *bs_new; 1831 *bs_new = *bs_old; 1832 *bs_old = tmp; 1833 1834 /* there are some fields that should not be swapped, move them back */ 1835 bdrv_move_feature_fields(&tmp, bs_old); 1836 bdrv_move_feature_fields(bs_old, bs_new); 1837 bdrv_move_feature_fields(bs_new, &tmp); 1838 1839 /* bs_new shouldn't be in bdrv_states even after the swap! */ 1840 assert(bs_new->device_name[0] == '\0'); 1841 1842 /* Check a few fields that should remain attached to the device */ 1843 assert(bs_new->dev == NULL); 1844 assert(bs_new->job == NULL); 1845 assert(bs_new->in_use == 0); 1846 assert(bs_new->io_limits_enabled == false); 1847 assert(!throttle_have_timer(&bs_new->throttle_state)); 1848 1849 bdrv_rebind(bs_new); 1850 bdrv_rebind(bs_old); 1851 } 1852 1853 /* 1854 * Add new bs contents at the top of an image chain while the chain is 1855 * live, while keeping required fields on the top layer. 1856 * 1857 * This will modify the BlockDriverState fields, and swap contents 1858 * between bs_new and bs_top. Both bs_new and bs_top are modified. 1859 * 1860 * bs_new is required to be anonymous. 1861 * 1862 * This function does not create any image files. 1863 */ 1864 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) 1865 { 1866 bdrv_swap(bs_new, bs_top); 1867 1868 /* The contents of 'tmp' will become bs_top, as we are 1869 * swapping bs_new and bs_top contents. */ 1870 bs_top->backing_hd = bs_new; 1871 bs_top->open_flags &= ~BDRV_O_NO_BACKING; 1872 pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file), 1873 bs_new->filename); 1874 pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format), 1875 bs_new->drv ? bs_new->drv->format_name : ""); 1876 } 1877 1878 static void bdrv_delete(BlockDriverState *bs) 1879 { 1880 assert(!bs->dev); 1881 assert(!bs->job); 1882 assert(!bs->in_use); 1883 assert(!bs->refcnt); 1884 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 1885 1886 bdrv_close(bs); 1887 1888 /* remove from list, if necessary */ 1889 bdrv_make_anon(bs); 1890 1891 g_free(bs); 1892 } 1893 1894 int bdrv_attach_dev(BlockDriverState *bs, void *dev) 1895 /* TODO change to DeviceState *dev when all users are qdevified */ 1896 { 1897 if (bs->dev) { 1898 return -EBUSY; 1899 } 1900 bs->dev = dev; 1901 bdrv_iostatus_reset(bs); 1902 return 0; 1903 } 1904 1905 /* TODO qdevified devices don't use this, remove when devices are qdevified */ 1906 void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev) 1907 { 1908 if (bdrv_attach_dev(bs, dev) < 0) { 1909 abort(); 1910 } 1911 } 1912 1913 void bdrv_detach_dev(BlockDriverState *bs, void *dev) 1914 /* TODO change to DeviceState *dev when all users are qdevified */ 1915 { 1916 assert(bs->dev == dev); 1917 bs->dev = NULL; 1918 bs->dev_ops = NULL; 1919 bs->dev_opaque = NULL; 1920 bs->buffer_alignment = 512; 1921 } 1922 1923 /* TODO change to return DeviceState * when all users are qdevified */ 1924 void *bdrv_get_attached_dev(BlockDriverState *bs) 1925 { 1926 return bs->dev; 1927 } 1928 1929 void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops, 1930 void *opaque) 1931 { 1932 bs->dev_ops = ops; 1933 bs->dev_opaque = opaque; 1934 } 1935 1936 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv, 1937 enum MonitorEvent ev, 1938 BlockErrorAction action, bool is_read) 1939 { 1940 QObject *data; 1941 const char *action_str; 1942 1943 switch (action) { 1944 case BDRV_ACTION_REPORT: 1945 action_str = "report"; 1946 break; 1947 case BDRV_ACTION_IGNORE: 1948 action_str = "ignore"; 1949 break; 1950 case BDRV_ACTION_STOP: 1951 action_str = "stop"; 1952 break; 1953 default: 1954 abort(); 1955 } 1956 1957 data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }", 1958 bdrv->device_name, 1959 action_str, 1960 is_read ? "read" : "write"); 1961 monitor_protocol_event(ev, data); 1962 1963 qobject_decref(data); 1964 } 1965 1966 static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected) 1967 { 1968 QObject *data; 1969 1970 data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }", 1971 bdrv_get_device_name(bs), ejected); 1972 monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data); 1973 1974 qobject_decref(data); 1975 } 1976 1977 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load) 1978 { 1979 if (bs->dev_ops && bs->dev_ops->change_media_cb) { 1980 bool tray_was_closed = !bdrv_dev_is_tray_open(bs); 1981 bs->dev_ops->change_media_cb(bs->dev_opaque, load); 1982 if (tray_was_closed) { 1983 /* tray open */ 1984 bdrv_emit_qmp_eject_event(bs, true); 1985 } 1986 if (load) { 1987 /* tray close */ 1988 bdrv_emit_qmp_eject_event(bs, false); 1989 } 1990 } 1991 } 1992 1993 bool bdrv_dev_has_removable_media(BlockDriverState *bs) 1994 { 1995 return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb); 1996 } 1997 1998 void bdrv_dev_eject_request(BlockDriverState *bs, bool force) 1999 { 2000 if (bs->dev_ops && bs->dev_ops->eject_request_cb) { 2001 bs->dev_ops->eject_request_cb(bs->dev_opaque, force); 2002 } 2003 } 2004 2005 bool bdrv_dev_is_tray_open(BlockDriverState *bs) 2006 { 2007 if (bs->dev_ops && bs->dev_ops->is_tray_open) { 2008 return bs->dev_ops->is_tray_open(bs->dev_opaque); 2009 } 2010 return false; 2011 } 2012 2013 static void bdrv_dev_resize_cb(BlockDriverState *bs) 2014 { 2015 if (bs->dev_ops && bs->dev_ops->resize_cb) { 2016 bs->dev_ops->resize_cb(bs->dev_opaque); 2017 } 2018 } 2019 2020 bool bdrv_dev_is_medium_locked(BlockDriverState *bs) 2021 { 2022 if (bs->dev_ops && bs->dev_ops->is_medium_locked) { 2023 return bs->dev_ops->is_medium_locked(bs->dev_opaque); 2024 } 2025 return false; 2026 } 2027 2028 /* 2029 * Run consistency checks on an image 2030 * 2031 * Returns 0 if the check could be completed (it doesn't mean that the image is 2032 * free of errors) or -errno when an internal error occurred. The results of the 2033 * check are stored in res. 2034 */ 2035 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) 2036 { 2037 if (bs->drv->bdrv_check == NULL) { 2038 return -ENOTSUP; 2039 } 2040 2041 memset(res, 0, sizeof(*res)); 2042 return bs->drv->bdrv_check(bs, res, fix); 2043 } 2044 2045 #define COMMIT_BUF_SECTORS 2048 2046 2047 /* commit COW file into the raw image */ 2048 int bdrv_commit(BlockDriverState *bs) 2049 { 2050 BlockDriver *drv = bs->drv; 2051 int64_t sector, total_sectors, length, backing_length; 2052 int n, ro, open_flags; 2053 int ret = 0; 2054 uint8_t *buf = NULL; 2055 char filename[PATH_MAX]; 2056 2057 if (!drv) 2058 return -ENOMEDIUM; 2059 2060 if (!bs->backing_hd) { 2061 return -ENOTSUP; 2062 } 2063 2064 if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) { 2065 return -EBUSY; 2066 } 2067 2068 ro = bs->backing_hd->read_only; 2069 /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */ 2070 pstrcpy(filename, sizeof(filename), bs->backing_hd->filename); 2071 open_flags = bs->backing_hd->open_flags; 2072 2073 if (ro) { 2074 if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) { 2075 return -EACCES; 2076 } 2077 } 2078 2079 length = bdrv_getlength(bs); 2080 if (length < 0) { 2081 ret = length; 2082 goto ro_cleanup; 2083 } 2084 2085 backing_length = bdrv_getlength(bs->backing_hd); 2086 if (backing_length < 0) { 2087 ret = backing_length; 2088 goto ro_cleanup; 2089 } 2090 2091 /* If our top snapshot is larger than the backing file image, 2092 * grow the backing file image if possible. If not possible, 2093 * we must return an error */ 2094 if (length > backing_length) { 2095 ret = bdrv_truncate(bs->backing_hd, length); 2096 if (ret < 0) { 2097 goto ro_cleanup; 2098 } 2099 } 2100 2101 total_sectors = length >> BDRV_SECTOR_BITS; 2102 buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); 2103 2104 for (sector = 0; sector < total_sectors; sector += n) { 2105 ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n); 2106 if (ret < 0) { 2107 goto ro_cleanup; 2108 } 2109 if (ret) { 2110 ret = bdrv_read(bs, sector, buf, n); 2111 if (ret < 0) { 2112 goto ro_cleanup; 2113 } 2114 2115 ret = bdrv_write(bs->backing_hd, sector, buf, n); 2116 if (ret < 0) { 2117 goto ro_cleanup; 2118 } 2119 } 2120 } 2121 2122 if (drv->bdrv_make_empty) { 2123 ret = drv->bdrv_make_empty(bs); 2124 if (ret < 0) { 2125 goto ro_cleanup; 2126 } 2127 bdrv_flush(bs); 2128 } 2129 2130 /* 2131 * Make sure all data we wrote to the backing device is actually 2132 * stable on disk. 2133 */ 2134 if (bs->backing_hd) { 2135 bdrv_flush(bs->backing_hd); 2136 } 2137 2138 ret = 0; 2139 ro_cleanup: 2140 g_free(buf); 2141 2142 if (ro) { 2143 /* ignoring error return here */ 2144 bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL); 2145 } 2146 2147 return ret; 2148 } 2149 2150 int bdrv_commit_all(void) 2151 { 2152 BlockDriverState *bs; 2153 2154 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 2155 if (bs->drv && bs->backing_hd) { 2156 int ret = bdrv_commit(bs); 2157 if (ret < 0) { 2158 return ret; 2159 } 2160 } 2161 } 2162 return 0; 2163 } 2164 2165 /** 2166 * Remove an active request from the tracked requests list 2167 * 2168 * This function should be called when a tracked request is completing. 2169 */ 2170 static void tracked_request_end(BdrvTrackedRequest *req) 2171 { 2172 QLIST_REMOVE(req, list); 2173 qemu_co_queue_restart_all(&req->wait_queue); 2174 } 2175 2176 /** 2177 * Add an active request to the tracked requests list 2178 */ 2179 static void tracked_request_begin(BdrvTrackedRequest *req, 2180 BlockDriverState *bs, 2181 int64_t sector_num, 2182 int nb_sectors, bool is_write) 2183 { 2184 *req = (BdrvTrackedRequest){ 2185 .bs = bs, 2186 .sector_num = sector_num, 2187 .nb_sectors = nb_sectors, 2188 .is_write = is_write, 2189 .co = qemu_coroutine_self(), 2190 }; 2191 2192 qemu_co_queue_init(&req->wait_queue); 2193 2194 QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); 2195 } 2196 2197 /** 2198 * Round a region to cluster boundaries 2199 */ 2200 void bdrv_round_to_clusters(BlockDriverState *bs, 2201 int64_t sector_num, int nb_sectors, 2202 int64_t *cluster_sector_num, 2203 int *cluster_nb_sectors) 2204 { 2205 BlockDriverInfo bdi; 2206 2207 if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { 2208 *cluster_sector_num = sector_num; 2209 *cluster_nb_sectors = nb_sectors; 2210 } else { 2211 int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE; 2212 *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c); 2213 *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num + 2214 nb_sectors, c); 2215 } 2216 } 2217 2218 static bool tracked_request_overlaps(BdrvTrackedRequest *req, 2219 int64_t sector_num, int nb_sectors) { 2220 /* aaaa bbbb */ 2221 if (sector_num >= req->sector_num + req->nb_sectors) { 2222 return false; 2223 } 2224 /* bbbb aaaa */ 2225 if (req->sector_num >= sector_num + nb_sectors) { 2226 return false; 2227 } 2228 return true; 2229 } 2230 2231 static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs, 2232 int64_t sector_num, int nb_sectors) 2233 { 2234 BdrvTrackedRequest *req; 2235 int64_t cluster_sector_num; 2236 int cluster_nb_sectors; 2237 bool retry; 2238 2239 /* If we touch the same cluster it counts as an overlap. This guarantees 2240 * that allocating writes will be serialized and not race with each other 2241 * for the same cluster. For example, in copy-on-read it ensures that the 2242 * CoR read and write operations are atomic and guest writes cannot 2243 * interleave between them. 2244 */ 2245 bdrv_round_to_clusters(bs, sector_num, nb_sectors, 2246 &cluster_sector_num, &cluster_nb_sectors); 2247 2248 do { 2249 retry = false; 2250 QLIST_FOREACH(req, &bs->tracked_requests, list) { 2251 if (tracked_request_overlaps(req, cluster_sector_num, 2252 cluster_nb_sectors)) { 2253 /* Hitting this means there was a reentrant request, for 2254 * example, a block driver issuing nested requests. This must 2255 * never happen since it means deadlock. 2256 */ 2257 assert(qemu_coroutine_self() != req->co); 2258 2259 qemu_co_queue_wait(&req->wait_queue); 2260 retry = true; 2261 break; 2262 } 2263 } 2264 } while (retry); 2265 } 2266 2267 /* 2268 * Return values: 2269 * 0 - success 2270 * -EINVAL - backing format specified, but no file 2271 * -ENOSPC - can't update the backing file because no space is left in the 2272 * image file header 2273 * -ENOTSUP - format driver doesn't support changing the backing file 2274 */ 2275 int bdrv_change_backing_file(BlockDriverState *bs, 2276 const char *backing_file, const char *backing_fmt) 2277 { 2278 BlockDriver *drv = bs->drv; 2279 int ret; 2280 2281 /* Backing file format doesn't make sense without a backing file */ 2282 if (backing_fmt && !backing_file) { 2283 return -EINVAL; 2284 } 2285 2286 if (drv->bdrv_change_backing_file != NULL) { 2287 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); 2288 } else { 2289 ret = -ENOTSUP; 2290 } 2291 2292 if (ret == 0) { 2293 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2294 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2295 } 2296 return ret; 2297 } 2298 2299 /* 2300 * Finds the image layer in the chain that has 'bs' as its backing file. 2301 * 2302 * active is the current topmost image. 2303 * 2304 * Returns NULL if bs is not found in active's image chain, 2305 * or if active == bs. 2306 */ 2307 BlockDriverState *bdrv_find_overlay(BlockDriverState *active, 2308 BlockDriverState *bs) 2309 { 2310 BlockDriverState *overlay = NULL; 2311 BlockDriverState *intermediate; 2312 2313 assert(active != NULL); 2314 assert(bs != NULL); 2315 2316 /* if bs is the same as active, then by definition it has no overlay 2317 */ 2318 if (active == bs) { 2319 return NULL; 2320 } 2321 2322 intermediate = active; 2323 while (intermediate->backing_hd) { 2324 if (intermediate->backing_hd == bs) { 2325 overlay = intermediate; 2326 break; 2327 } 2328 intermediate = intermediate->backing_hd; 2329 } 2330 2331 return overlay; 2332 } 2333 2334 typedef struct BlkIntermediateStates { 2335 BlockDriverState *bs; 2336 QSIMPLEQ_ENTRY(BlkIntermediateStates) entry; 2337 } BlkIntermediateStates; 2338 2339 2340 /* 2341 * Drops images above 'base' up to and including 'top', and sets the image 2342 * above 'top' to have base as its backing file. 2343 * 2344 * Requires that the overlay to 'top' is opened r/w, so that the backing file 2345 * information in 'bs' can be properly updated. 2346 * 2347 * E.g., this will convert the following chain: 2348 * bottom <- base <- intermediate <- top <- active 2349 * 2350 * to 2351 * 2352 * bottom <- base <- active 2353 * 2354 * It is allowed for bottom==base, in which case it converts: 2355 * 2356 * base <- intermediate <- top <- active 2357 * 2358 * to 2359 * 2360 * base <- active 2361 * 2362 * Error conditions: 2363 * if active == top, that is considered an error 2364 * 2365 */ 2366 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, 2367 BlockDriverState *base) 2368 { 2369 BlockDriverState *intermediate; 2370 BlockDriverState *base_bs = NULL; 2371 BlockDriverState *new_top_bs = NULL; 2372 BlkIntermediateStates *intermediate_state, *next; 2373 int ret = -EIO; 2374 2375 QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete; 2376 QSIMPLEQ_INIT(&states_to_delete); 2377 2378 if (!top->drv || !base->drv) { 2379 goto exit; 2380 } 2381 2382 new_top_bs = bdrv_find_overlay(active, top); 2383 2384 if (new_top_bs == NULL) { 2385 /* we could not find the image above 'top', this is an error */ 2386 goto exit; 2387 } 2388 2389 /* special case of new_top_bs->backing_hd already pointing to base - nothing 2390 * to do, no intermediate images */ 2391 if (new_top_bs->backing_hd == base) { 2392 ret = 0; 2393 goto exit; 2394 } 2395 2396 intermediate = top; 2397 2398 /* now we will go down through the list, and add each BDS we find 2399 * into our deletion queue, until we hit the 'base' 2400 */ 2401 while (intermediate) { 2402 intermediate_state = g_malloc0(sizeof(BlkIntermediateStates)); 2403 intermediate_state->bs = intermediate; 2404 QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry); 2405 2406 if (intermediate->backing_hd == base) { 2407 base_bs = intermediate->backing_hd; 2408 break; 2409 } 2410 intermediate = intermediate->backing_hd; 2411 } 2412 if (base_bs == NULL) { 2413 /* something went wrong, we did not end at the base. safely 2414 * unravel everything, and exit with error */ 2415 goto exit; 2416 } 2417 2418 /* success - we can delete the intermediate states, and link top->base */ 2419 ret = bdrv_change_backing_file(new_top_bs, base_bs->filename, 2420 base_bs->drv ? base_bs->drv->format_name : ""); 2421 if (ret) { 2422 goto exit; 2423 } 2424 new_top_bs->backing_hd = base_bs; 2425 2426 2427 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2428 /* so that bdrv_close() does not recursively close the chain */ 2429 intermediate_state->bs->backing_hd = NULL; 2430 bdrv_unref(intermediate_state->bs); 2431 } 2432 ret = 0; 2433 2434 exit: 2435 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2436 g_free(intermediate_state); 2437 } 2438 return ret; 2439 } 2440 2441 2442 static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, 2443 size_t size) 2444 { 2445 int64_t len; 2446 2447 if (!bdrv_is_inserted(bs)) 2448 return -ENOMEDIUM; 2449 2450 if (bs->growable) 2451 return 0; 2452 2453 len = bdrv_getlength(bs); 2454 2455 if (offset < 0) 2456 return -EIO; 2457 2458 if ((offset > len) || (len - offset < size)) 2459 return -EIO; 2460 2461 return 0; 2462 } 2463 2464 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, 2465 int nb_sectors) 2466 { 2467 return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE, 2468 nb_sectors * BDRV_SECTOR_SIZE); 2469 } 2470 2471 typedef struct RwCo { 2472 BlockDriverState *bs; 2473 int64_t sector_num; 2474 int nb_sectors; 2475 QEMUIOVector *qiov; 2476 bool is_write; 2477 int ret; 2478 BdrvRequestFlags flags; 2479 } RwCo; 2480 2481 static void coroutine_fn bdrv_rw_co_entry(void *opaque) 2482 { 2483 RwCo *rwco = opaque; 2484 2485 if (!rwco->is_write) { 2486 rwco->ret = bdrv_co_do_readv(rwco->bs, rwco->sector_num, 2487 rwco->nb_sectors, rwco->qiov, 2488 rwco->flags); 2489 } else { 2490 rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num, 2491 rwco->nb_sectors, rwco->qiov, 2492 rwco->flags); 2493 } 2494 } 2495 2496 /* 2497 * Process a vectored synchronous request using coroutines 2498 */ 2499 static int bdrv_rwv_co(BlockDriverState *bs, int64_t sector_num, 2500 QEMUIOVector *qiov, bool is_write, 2501 BdrvRequestFlags flags) 2502 { 2503 Coroutine *co; 2504 RwCo rwco = { 2505 .bs = bs, 2506 .sector_num = sector_num, 2507 .nb_sectors = qiov->size >> BDRV_SECTOR_BITS, 2508 .qiov = qiov, 2509 .is_write = is_write, 2510 .ret = NOT_DONE, 2511 .flags = flags, 2512 }; 2513 assert((qiov->size & (BDRV_SECTOR_SIZE - 1)) == 0); 2514 2515 /** 2516 * In sync call context, when the vcpu is blocked, this throttling timer 2517 * will not fire; so the I/O throttling function has to be disabled here 2518 * if it has been enabled. 2519 */ 2520 if (bs->io_limits_enabled) { 2521 fprintf(stderr, "Disabling I/O throttling on '%s' due " 2522 "to synchronous I/O.\n", bdrv_get_device_name(bs)); 2523 bdrv_io_limits_disable(bs); 2524 } 2525 2526 if (qemu_in_coroutine()) { 2527 /* Fast-path if already in coroutine context */ 2528 bdrv_rw_co_entry(&rwco); 2529 } else { 2530 co = qemu_coroutine_create(bdrv_rw_co_entry); 2531 qemu_coroutine_enter(co, &rwco); 2532 while (rwco.ret == NOT_DONE) { 2533 qemu_aio_wait(); 2534 } 2535 } 2536 return rwco.ret; 2537 } 2538 2539 /* 2540 * Process a synchronous request using coroutines 2541 */ 2542 static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, 2543 int nb_sectors, bool is_write, BdrvRequestFlags flags) 2544 { 2545 QEMUIOVector qiov; 2546 struct iovec iov = { 2547 .iov_base = (void *)buf, 2548 .iov_len = nb_sectors * BDRV_SECTOR_SIZE, 2549 }; 2550 2551 qemu_iovec_init_external(&qiov, &iov, 1); 2552 return bdrv_rwv_co(bs, sector_num, &qiov, is_write, flags); 2553 } 2554 2555 /* return < 0 if error. See bdrv_write() for the return codes */ 2556 int bdrv_read(BlockDriverState *bs, int64_t sector_num, 2557 uint8_t *buf, int nb_sectors) 2558 { 2559 return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0); 2560 } 2561 2562 /* Just like bdrv_read(), but with I/O throttling temporarily disabled */ 2563 int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, 2564 uint8_t *buf, int nb_sectors) 2565 { 2566 bool enabled; 2567 int ret; 2568 2569 enabled = bs->io_limits_enabled; 2570 bs->io_limits_enabled = false; 2571 ret = bdrv_read(bs, sector_num, buf, nb_sectors); 2572 bs->io_limits_enabled = enabled; 2573 return ret; 2574 } 2575 2576 /* Return < 0 if error. Important errors are: 2577 -EIO generic I/O error (may happen for all errors) 2578 -ENOMEDIUM No media inserted. 2579 -EINVAL Invalid sector number or nb_sectors 2580 -EACCES Trying to write a read-only device 2581 */ 2582 int bdrv_write(BlockDriverState *bs, int64_t sector_num, 2583 const uint8_t *buf, int nb_sectors) 2584 { 2585 return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0); 2586 } 2587 2588 int bdrv_writev(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov) 2589 { 2590 return bdrv_rwv_co(bs, sector_num, qiov, true, 0); 2591 } 2592 2593 int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, 2594 int nb_sectors, BdrvRequestFlags flags) 2595 { 2596 return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true, 2597 BDRV_REQ_ZERO_WRITE | flags); 2598 } 2599 2600 /* 2601 * Completely zero out a block device with the help of bdrv_write_zeroes. 2602 * The operation is sped up by checking the block status and only writing 2603 * zeroes to the device if they currently do not return zeroes. Optional 2604 * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). 2605 * 2606 * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). 2607 */ 2608 int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) 2609 { 2610 int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; 2611 int64_t ret, nb_sectors, sector_num = 0; 2612 int n; 2613 2614 for (;;) { 2615 nb_sectors = target_size - sector_num; 2616 if (nb_sectors <= 0) { 2617 return 0; 2618 } 2619 if (nb_sectors > INT_MAX) { 2620 nb_sectors = INT_MAX; 2621 } 2622 ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); 2623 if (ret < 0) { 2624 error_report("error getting block status at sector %" PRId64 ": %s", 2625 sector_num, strerror(-ret)); 2626 return ret; 2627 } 2628 if (ret & BDRV_BLOCK_ZERO) { 2629 sector_num += n; 2630 continue; 2631 } 2632 ret = bdrv_write_zeroes(bs, sector_num, n, flags); 2633 if (ret < 0) { 2634 error_report("error writing zeroes at sector %" PRId64 ": %s", 2635 sector_num, strerror(-ret)); 2636 return ret; 2637 } 2638 sector_num += n; 2639 } 2640 } 2641 2642 int bdrv_pread(BlockDriverState *bs, int64_t offset, 2643 void *buf, int count1) 2644 { 2645 uint8_t tmp_buf[BDRV_SECTOR_SIZE]; 2646 int len, nb_sectors, count; 2647 int64_t sector_num; 2648 int ret; 2649 2650 count = count1; 2651 /* first read to align to sector start */ 2652 len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1); 2653 if (len > count) 2654 len = count; 2655 sector_num = offset >> BDRV_SECTOR_BITS; 2656 if (len > 0) { 2657 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2658 return ret; 2659 memcpy(buf, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), len); 2660 count -= len; 2661 if (count == 0) 2662 return count1; 2663 sector_num++; 2664 buf += len; 2665 } 2666 2667 /* read the sectors "in place" */ 2668 nb_sectors = count >> BDRV_SECTOR_BITS; 2669 if (nb_sectors > 0) { 2670 if ((ret = bdrv_read(bs, sector_num, buf, nb_sectors)) < 0) 2671 return ret; 2672 sector_num += nb_sectors; 2673 len = nb_sectors << BDRV_SECTOR_BITS; 2674 buf += len; 2675 count -= len; 2676 } 2677 2678 /* add data from the last sector */ 2679 if (count > 0) { 2680 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2681 return ret; 2682 memcpy(buf, tmp_buf, count); 2683 } 2684 return count1; 2685 } 2686 2687 int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov) 2688 { 2689 uint8_t tmp_buf[BDRV_SECTOR_SIZE]; 2690 int len, nb_sectors, count; 2691 int64_t sector_num; 2692 int ret; 2693 2694 count = qiov->size; 2695 2696 /* first write to align to sector start */ 2697 len = (BDRV_SECTOR_SIZE - offset) & (BDRV_SECTOR_SIZE - 1); 2698 if (len > count) 2699 len = count; 2700 sector_num = offset >> BDRV_SECTOR_BITS; 2701 if (len > 0) { 2702 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2703 return ret; 2704 qemu_iovec_to_buf(qiov, 0, tmp_buf + (offset & (BDRV_SECTOR_SIZE - 1)), 2705 len); 2706 if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0) 2707 return ret; 2708 count -= len; 2709 if (count == 0) 2710 return qiov->size; 2711 sector_num++; 2712 } 2713 2714 /* write the sectors "in place" */ 2715 nb_sectors = count >> BDRV_SECTOR_BITS; 2716 if (nb_sectors > 0) { 2717 QEMUIOVector qiov_inplace; 2718 2719 qemu_iovec_init(&qiov_inplace, qiov->niov); 2720 qemu_iovec_concat(&qiov_inplace, qiov, len, 2721 nb_sectors << BDRV_SECTOR_BITS); 2722 ret = bdrv_writev(bs, sector_num, &qiov_inplace); 2723 qemu_iovec_destroy(&qiov_inplace); 2724 if (ret < 0) { 2725 return ret; 2726 } 2727 2728 sector_num += nb_sectors; 2729 len = nb_sectors << BDRV_SECTOR_BITS; 2730 count -= len; 2731 } 2732 2733 /* add data from the last sector */ 2734 if (count > 0) { 2735 if ((ret = bdrv_read(bs, sector_num, tmp_buf, 1)) < 0) 2736 return ret; 2737 qemu_iovec_to_buf(qiov, qiov->size - count, tmp_buf, count); 2738 if ((ret = bdrv_write(bs, sector_num, tmp_buf, 1)) < 0) 2739 return ret; 2740 } 2741 return qiov->size; 2742 } 2743 2744 int bdrv_pwrite(BlockDriverState *bs, int64_t offset, 2745 const void *buf, int count1) 2746 { 2747 QEMUIOVector qiov; 2748 struct iovec iov = { 2749 .iov_base = (void *) buf, 2750 .iov_len = count1, 2751 }; 2752 2753 qemu_iovec_init_external(&qiov, &iov, 1); 2754 return bdrv_pwritev(bs, offset, &qiov); 2755 } 2756 2757 /* 2758 * Writes to the file and ensures that no writes are reordered across this 2759 * request (acts as a barrier) 2760 * 2761 * Returns 0 on success, -errno in error cases. 2762 */ 2763 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, 2764 const void *buf, int count) 2765 { 2766 int ret; 2767 2768 ret = bdrv_pwrite(bs, offset, buf, count); 2769 if (ret < 0) { 2770 return ret; 2771 } 2772 2773 /* No flush needed for cache modes that already do it */ 2774 if (bs->enable_write_cache) { 2775 bdrv_flush(bs); 2776 } 2777 2778 return 0; 2779 } 2780 2781 static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, 2782 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) 2783 { 2784 /* Perform I/O through a temporary buffer so that users who scribble over 2785 * their read buffer while the operation is in progress do not end up 2786 * modifying the image file. This is critical for zero-copy guest I/O 2787 * where anything might happen inside guest memory. 2788 */ 2789 void *bounce_buffer; 2790 2791 BlockDriver *drv = bs->drv; 2792 struct iovec iov; 2793 QEMUIOVector bounce_qiov; 2794 int64_t cluster_sector_num; 2795 int cluster_nb_sectors; 2796 size_t skip_bytes; 2797 int ret; 2798 2799 /* Cover entire cluster so no additional backing file I/O is required when 2800 * allocating cluster in the image file. 2801 */ 2802 bdrv_round_to_clusters(bs, sector_num, nb_sectors, 2803 &cluster_sector_num, &cluster_nb_sectors); 2804 2805 trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, 2806 cluster_sector_num, cluster_nb_sectors); 2807 2808 iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE; 2809 iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len); 2810 qemu_iovec_init_external(&bounce_qiov, &iov, 1); 2811 2812 ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors, 2813 &bounce_qiov); 2814 if (ret < 0) { 2815 goto err; 2816 } 2817 2818 if (drv->bdrv_co_write_zeroes && 2819 buffer_is_zero(bounce_buffer, iov.iov_len)) { 2820 ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, 2821 cluster_nb_sectors, 0); 2822 } else { 2823 /* This does not change the data on the disk, it is not necessary 2824 * to flush even in cache=writethrough mode. 2825 */ 2826 ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, 2827 &bounce_qiov); 2828 } 2829 2830 if (ret < 0) { 2831 /* It might be okay to ignore write errors for guest requests. If this 2832 * is a deliberate copy-on-read then we don't want to ignore the error. 2833 * Simply report it in all cases. 2834 */ 2835 goto err; 2836 } 2837 2838 skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE; 2839 qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, 2840 nb_sectors * BDRV_SECTOR_SIZE); 2841 2842 err: 2843 qemu_vfree(bounce_buffer); 2844 return ret; 2845 } 2846 2847 /* 2848 * Handle a read request in coroutine context 2849 */ 2850 static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, 2851 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 2852 BdrvRequestFlags flags) 2853 { 2854 BlockDriver *drv = bs->drv; 2855 BdrvTrackedRequest req; 2856 int ret; 2857 2858 if (!drv) { 2859 return -ENOMEDIUM; 2860 } 2861 if (bdrv_check_request(bs, sector_num, nb_sectors)) { 2862 return -EIO; 2863 } 2864 2865 if (bs->copy_on_read) { 2866 flags |= BDRV_REQ_COPY_ON_READ; 2867 } 2868 if (flags & BDRV_REQ_COPY_ON_READ) { 2869 bs->copy_on_read_in_flight++; 2870 } 2871 2872 if (bs->copy_on_read_in_flight) { 2873 wait_for_overlapping_requests(bs, sector_num, nb_sectors); 2874 } 2875 2876 /* throttling disk I/O */ 2877 if (bs->io_limits_enabled) { 2878 bdrv_io_limits_intercept(bs, nb_sectors, false); 2879 } 2880 2881 tracked_request_begin(&req, bs, sector_num, nb_sectors, false); 2882 2883 if (flags & BDRV_REQ_COPY_ON_READ) { 2884 int pnum; 2885 2886 ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum); 2887 if (ret < 0) { 2888 goto out; 2889 } 2890 2891 if (!ret || pnum != nb_sectors) { 2892 ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov); 2893 goto out; 2894 } 2895 } 2896 2897 if (!(bs->zero_beyond_eof && bs->growable)) { 2898 ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); 2899 } else { 2900 /* Read zeros after EOF of growable BDSes */ 2901 int64_t len, total_sectors, max_nb_sectors; 2902 2903 len = bdrv_getlength(bs); 2904 if (len < 0) { 2905 ret = len; 2906 goto out; 2907 } 2908 2909 total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE); 2910 max_nb_sectors = MAX(0, total_sectors - sector_num); 2911 if (max_nb_sectors > 0) { 2912 ret = drv->bdrv_co_readv(bs, sector_num, 2913 MIN(nb_sectors, max_nb_sectors), qiov); 2914 } else { 2915 ret = 0; 2916 } 2917 2918 /* Reading beyond end of file is supposed to produce zeroes */ 2919 if (ret == 0 && total_sectors < sector_num + nb_sectors) { 2920 uint64_t offset = MAX(0, total_sectors - sector_num); 2921 uint64_t bytes = (sector_num + nb_sectors - offset) * 2922 BDRV_SECTOR_SIZE; 2923 qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes); 2924 } 2925 } 2926 2927 out: 2928 tracked_request_end(&req); 2929 2930 if (flags & BDRV_REQ_COPY_ON_READ) { 2931 bs->copy_on_read_in_flight--; 2932 } 2933 2934 return ret; 2935 } 2936 2937 int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, 2938 int nb_sectors, QEMUIOVector *qiov) 2939 { 2940 trace_bdrv_co_readv(bs, sector_num, nb_sectors); 2941 2942 return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0); 2943 } 2944 2945 int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, 2946 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) 2947 { 2948 trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors); 2949 2950 return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 2951 BDRV_REQ_COPY_ON_READ); 2952 } 2953 2954 /* if no limit is specified in the BlockLimits use a default 2955 * of 32768 512-byte sectors (16 MiB) per request. 2956 */ 2957 #define MAX_WRITE_ZEROES_DEFAULT 32768 2958 2959 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, 2960 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2961 { 2962 BlockDriver *drv = bs->drv; 2963 QEMUIOVector qiov; 2964 struct iovec iov = {0}; 2965 int ret = 0; 2966 2967 int max_write_zeroes = bs->bl.max_write_zeroes ? 2968 bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT; 2969 2970 while (nb_sectors > 0 && !ret) { 2971 int num = nb_sectors; 2972 2973 /* Align request. Block drivers can expect the "bulk" of the request 2974 * to be aligned. 2975 */ 2976 if (bs->bl.write_zeroes_alignment 2977 && num > bs->bl.write_zeroes_alignment) { 2978 if (sector_num % bs->bl.write_zeroes_alignment != 0) { 2979 /* Make a small request up to the first aligned sector. */ 2980 num = bs->bl.write_zeroes_alignment; 2981 num -= sector_num % bs->bl.write_zeroes_alignment; 2982 } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) { 2983 /* Shorten the request to the last aligned sector. num cannot 2984 * underflow because num > bs->bl.write_zeroes_alignment. 2985 */ 2986 num -= (sector_num + num) % bs->bl.write_zeroes_alignment; 2987 } 2988 } 2989 2990 /* limit request size */ 2991 if (num > max_write_zeroes) { 2992 num = max_write_zeroes; 2993 } 2994 2995 ret = -ENOTSUP; 2996 /* First try the efficient write zeroes operation */ 2997 if (drv->bdrv_co_write_zeroes) { 2998 ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags); 2999 } 3000 3001 if (ret == -ENOTSUP) { 3002 /* Fall back to bounce buffer if write zeroes is unsupported */ 3003 iov.iov_len = num * BDRV_SECTOR_SIZE; 3004 if (iov.iov_base == NULL) { 3005 iov.iov_base = qemu_blockalign(bs, num * BDRV_SECTOR_SIZE); 3006 memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE); 3007 } 3008 qemu_iovec_init_external(&qiov, &iov, 1); 3009 3010 ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov); 3011 3012 /* Keep bounce buffer around if it is big enough for all 3013 * all future requests. 3014 */ 3015 if (num < max_write_zeroes) { 3016 qemu_vfree(iov.iov_base); 3017 iov.iov_base = NULL; 3018 } 3019 } 3020 3021 sector_num += num; 3022 nb_sectors -= num; 3023 } 3024 3025 qemu_vfree(iov.iov_base); 3026 return ret; 3027 } 3028 3029 /* 3030 * Handle a write request in coroutine context 3031 */ 3032 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 3033 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 3034 BdrvRequestFlags flags) 3035 { 3036 BlockDriver *drv = bs->drv; 3037 BdrvTrackedRequest req; 3038 int ret; 3039 3040 if (!bs->drv) { 3041 return -ENOMEDIUM; 3042 } 3043 if (bs->read_only) { 3044 return -EACCES; 3045 } 3046 if (bdrv_check_request(bs, sector_num, nb_sectors)) { 3047 return -EIO; 3048 } 3049 3050 if (bs->copy_on_read_in_flight) { 3051 wait_for_overlapping_requests(bs, sector_num, nb_sectors); 3052 } 3053 3054 /* throttling disk I/O */ 3055 if (bs->io_limits_enabled) { 3056 bdrv_io_limits_intercept(bs, nb_sectors, true); 3057 } 3058 3059 tracked_request_begin(&req, bs, sector_num, nb_sectors, true); 3060 3061 ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req); 3062 3063 if (ret < 0) { 3064 /* Do nothing, write notifier decided to fail this request */ 3065 } else if (flags & BDRV_REQ_ZERO_WRITE) { 3066 ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); 3067 } else { 3068 ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); 3069 } 3070 3071 if (ret == 0 && !bs->enable_write_cache) { 3072 ret = bdrv_co_flush(bs); 3073 } 3074 3075 bdrv_set_dirty(bs, sector_num, nb_sectors); 3076 3077 if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { 3078 bs->wr_highest_sector = sector_num + nb_sectors - 1; 3079 } 3080 if (bs->growable && ret >= 0) { 3081 bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); 3082 } 3083 3084 tracked_request_end(&req); 3085 3086 return ret; 3087 } 3088 3089 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, 3090 int nb_sectors, QEMUIOVector *qiov) 3091 { 3092 trace_bdrv_co_writev(bs, sector_num, nb_sectors); 3093 3094 return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0); 3095 } 3096 3097 int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, 3098 int64_t sector_num, int nb_sectors, 3099 BdrvRequestFlags flags) 3100 { 3101 trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags); 3102 3103 if (!(bs->open_flags & BDRV_O_UNMAP)) { 3104 flags &= ~BDRV_REQ_MAY_UNMAP; 3105 } 3106 3107 return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, 3108 BDRV_REQ_ZERO_WRITE | flags); 3109 } 3110 3111 /** 3112 * Truncate file to 'offset' bytes (needed only for file protocols) 3113 */ 3114 int bdrv_truncate(BlockDriverState *bs, int64_t offset) 3115 { 3116 BlockDriver *drv = bs->drv; 3117 int ret; 3118 if (!drv) 3119 return -ENOMEDIUM; 3120 if (!drv->bdrv_truncate) 3121 return -ENOTSUP; 3122 if (bs->read_only) 3123 return -EACCES; 3124 if (bdrv_in_use(bs)) 3125 return -EBUSY; 3126 ret = drv->bdrv_truncate(bs, offset); 3127 if (ret == 0) { 3128 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); 3129 bdrv_dev_resize_cb(bs); 3130 } 3131 return ret; 3132 } 3133 3134 /** 3135 * Length of a allocated file in bytes. Sparse files are counted by actual 3136 * allocated space. Return < 0 if error or unknown. 3137 */ 3138 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) 3139 { 3140 BlockDriver *drv = bs->drv; 3141 if (!drv) { 3142 return -ENOMEDIUM; 3143 } 3144 if (drv->bdrv_get_allocated_file_size) { 3145 return drv->bdrv_get_allocated_file_size(bs); 3146 } 3147 if (bs->file) { 3148 return bdrv_get_allocated_file_size(bs->file); 3149 } 3150 return -ENOTSUP; 3151 } 3152 3153 /** 3154 * Length of a file in bytes. Return < 0 if error or unknown. 3155 */ 3156 int64_t bdrv_getlength(BlockDriverState *bs) 3157 { 3158 BlockDriver *drv = bs->drv; 3159 if (!drv) 3160 return -ENOMEDIUM; 3161 3162 if (drv->has_variable_length) { 3163 int ret = refresh_total_sectors(bs, bs->total_sectors); 3164 if (ret < 0) { 3165 return ret; 3166 } 3167 } 3168 return bs->total_sectors * BDRV_SECTOR_SIZE; 3169 } 3170 3171 /* return 0 as number of sectors if no device present or error */ 3172 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) 3173 { 3174 int64_t length; 3175 length = bdrv_getlength(bs); 3176 if (length < 0) 3177 length = 0; 3178 else 3179 length = length >> BDRV_SECTOR_BITS; 3180 *nb_sectors_ptr = length; 3181 } 3182 3183 void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error, 3184 BlockdevOnError on_write_error) 3185 { 3186 bs->on_read_error = on_read_error; 3187 bs->on_write_error = on_write_error; 3188 } 3189 3190 BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read) 3191 { 3192 return is_read ? bs->on_read_error : bs->on_write_error; 3193 } 3194 3195 BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error) 3196 { 3197 BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error; 3198 3199 switch (on_err) { 3200 case BLOCKDEV_ON_ERROR_ENOSPC: 3201 return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT; 3202 case BLOCKDEV_ON_ERROR_STOP: 3203 return BDRV_ACTION_STOP; 3204 case BLOCKDEV_ON_ERROR_REPORT: 3205 return BDRV_ACTION_REPORT; 3206 case BLOCKDEV_ON_ERROR_IGNORE: 3207 return BDRV_ACTION_IGNORE; 3208 default: 3209 abort(); 3210 } 3211 } 3212 3213 /* This is done by device models because, while the block layer knows 3214 * about the error, it does not know whether an operation comes from 3215 * the device or the block layer (from a job, for example). 3216 */ 3217 void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action, 3218 bool is_read, int error) 3219 { 3220 assert(error >= 0); 3221 bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read); 3222 if (action == BDRV_ACTION_STOP) { 3223 vm_stop(RUN_STATE_IO_ERROR); 3224 bdrv_iostatus_set_err(bs, error); 3225 } 3226 } 3227 3228 int bdrv_is_read_only(BlockDriverState *bs) 3229 { 3230 return bs->read_only; 3231 } 3232 3233 int bdrv_is_sg(BlockDriverState *bs) 3234 { 3235 return bs->sg; 3236 } 3237 3238 int bdrv_enable_write_cache(BlockDriverState *bs) 3239 { 3240 return bs->enable_write_cache; 3241 } 3242 3243 void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce) 3244 { 3245 bs->enable_write_cache = wce; 3246 3247 /* so a reopen() will preserve wce */ 3248 if (wce) { 3249 bs->open_flags |= BDRV_O_CACHE_WB; 3250 } else { 3251 bs->open_flags &= ~BDRV_O_CACHE_WB; 3252 } 3253 } 3254 3255 int bdrv_is_encrypted(BlockDriverState *bs) 3256 { 3257 if (bs->backing_hd && bs->backing_hd->encrypted) 3258 return 1; 3259 return bs->encrypted; 3260 } 3261 3262 int bdrv_key_required(BlockDriverState *bs) 3263 { 3264 BlockDriverState *backing_hd = bs->backing_hd; 3265 3266 if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key) 3267 return 1; 3268 return (bs->encrypted && !bs->valid_key); 3269 } 3270 3271 int bdrv_set_key(BlockDriverState *bs, const char *key) 3272 { 3273 int ret; 3274 if (bs->backing_hd && bs->backing_hd->encrypted) { 3275 ret = bdrv_set_key(bs->backing_hd, key); 3276 if (ret < 0) 3277 return ret; 3278 if (!bs->encrypted) 3279 return 0; 3280 } 3281 if (!bs->encrypted) { 3282 return -EINVAL; 3283 } else if (!bs->drv || !bs->drv->bdrv_set_key) { 3284 return -ENOMEDIUM; 3285 } 3286 ret = bs->drv->bdrv_set_key(bs, key); 3287 if (ret < 0) { 3288 bs->valid_key = 0; 3289 } else if (!bs->valid_key) { 3290 bs->valid_key = 1; 3291 /* call the change callback now, we skipped it on open */ 3292 bdrv_dev_change_media_cb(bs, true); 3293 } 3294 return ret; 3295 } 3296 3297 const char *bdrv_get_format_name(BlockDriverState *bs) 3298 { 3299 return bs->drv ? bs->drv->format_name : NULL; 3300 } 3301 3302 void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 3303 void *opaque) 3304 { 3305 BlockDriver *drv; 3306 3307 QLIST_FOREACH(drv, &bdrv_drivers, list) { 3308 it(opaque, drv->format_name); 3309 } 3310 } 3311 3312 /* This function is to find block backend bs */ 3313 BlockDriverState *bdrv_find(const char *name) 3314 { 3315 BlockDriverState *bs; 3316 3317 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 3318 if (!strcmp(name, bs->device_name)) { 3319 return bs; 3320 } 3321 } 3322 return NULL; 3323 } 3324 3325 /* This function is to find a node in the bs graph */ 3326 BlockDriverState *bdrv_find_node(const char *node_name) 3327 { 3328 BlockDriverState *bs; 3329 3330 assert(node_name); 3331 3332 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3333 if (!strcmp(node_name, bs->node_name)) { 3334 return bs; 3335 } 3336 } 3337 return NULL; 3338 } 3339 3340 /* Put this QMP function here so it can access the static graph_bdrv_states. */ 3341 BlockDeviceInfoList *bdrv_named_nodes_list(void) 3342 { 3343 BlockDeviceInfoList *list, *entry; 3344 BlockDriverState *bs; 3345 3346 list = NULL; 3347 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3348 entry = g_malloc0(sizeof(*entry)); 3349 entry->value = bdrv_block_device_info(bs); 3350 entry->next = list; 3351 list = entry; 3352 } 3353 3354 return list; 3355 } 3356 3357 BlockDriverState *bdrv_lookup_bs(const char *device, 3358 const char *node_name, 3359 Error **errp) 3360 { 3361 BlockDriverState *bs = NULL; 3362 3363 if ((!device && !node_name) || (device && node_name)) { 3364 error_setg(errp, "Use either device or node-name but not both"); 3365 return NULL; 3366 } 3367 3368 if (device) { 3369 bs = bdrv_find(device); 3370 3371 if (!bs) { 3372 error_set(errp, QERR_DEVICE_NOT_FOUND, device); 3373 return NULL; 3374 } 3375 3376 return bs; 3377 } 3378 3379 bs = bdrv_find_node(node_name); 3380 3381 if (!bs) { 3382 error_set(errp, QERR_DEVICE_NOT_FOUND, node_name); 3383 return NULL; 3384 } 3385 3386 return bs; 3387 } 3388 3389 BlockDriverState *bdrv_next(BlockDriverState *bs) 3390 { 3391 if (!bs) { 3392 return QTAILQ_FIRST(&bdrv_states); 3393 } 3394 return QTAILQ_NEXT(bs, device_list); 3395 } 3396 3397 void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque) 3398 { 3399 BlockDriverState *bs; 3400 3401 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 3402 it(opaque, bs); 3403 } 3404 } 3405 3406 const char *bdrv_get_device_name(BlockDriverState *bs) 3407 { 3408 return bs->device_name; 3409 } 3410 3411 int bdrv_get_flags(BlockDriverState *bs) 3412 { 3413 return bs->open_flags; 3414 } 3415 3416 int bdrv_flush_all(void) 3417 { 3418 BlockDriverState *bs; 3419 int result = 0; 3420 3421 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 3422 int ret = bdrv_flush(bs); 3423 if (ret < 0 && !result) { 3424 result = ret; 3425 } 3426 } 3427 3428 return result; 3429 } 3430 3431 int bdrv_has_zero_init_1(BlockDriverState *bs) 3432 { 3433 return 1; 3434 } 3435 3436 int bdrv_has_zero_init(BlockDriverState *bs) 3437 { 3438 assert(bs->drv); 3439 3440 /* If BS is a copy on write image, it is initialized to 3441 the contents of the base image, which may not be zeroes. */ 3442 if (bs->backing_hd) { 3443 return 0; 3444 } 3445 if (bs->drv->bdrv_has_zero_init) { 3446 return bs->drv->bdrv_has_zero_init(bs); 3447 } 3448 3449 /* safe default */ 3450 return 0; 3451 } 3452 3453 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) 3454 { 3455 BlockDriverInfo bdi; 3456 3457 if (bs->backing_hd) { 3458 return false; 3459 } 3460 3461 if (bdrv_get_info(bs, &bdi) == 0) { 3462 return bdi.unallocated_blocks_are_zero; 3463 } 3464 3465 return false; 3466 } 3467 3468 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) 3469 { 3470 BlockDriverInfo bdi; 3471 3472 if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { 3473 return false; 3474 } 3475 3476 if (bdrv_get_info(bs, &bdi) == 0) { 3477 return bdi.can_write_zeroes_with_unmap; 3478 } 3479 3480 return false; 3481 } 3482 3483 typedef struct BdrvCoGetBlockStatusData { 3484 BlockDriverState *bs; 3485 BlockDriverState *base; 3486 int64_t sector_num; 3487 int nb_sectors; 3488 int *pnum; 3489 int64_t ret; 3490 bool done; 3491 } BdrvCoGetBlockStatusData; 3492 3493 /* 3494 * Returns true iff the specified sector is present in the disk image. Drivers 3495 * not implementing the functionality are assumed to not support backing files, 3496 * hence all their sectors are reported as allocated. 3497 * 3498 * If 'sector_num' is beyond the end of the disk image the return value is 0 3499 * and 'pnum' is set to 0. 3500 * 3501 * 'pnum' is set to the number of sectors (including and immediately following 3502 * the specified sector) that are known to be in the same 3503 * allocated/unallocated state. 3504 * 3505 * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes 3506 * beyond the end of the disk image it will be clamped. 3507 */ 3508 static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, 3509 int64_t sector_num, 3510 int nb_sectors, int *pnum) 3511 { 3512 int64_t length; 3513 int64_t n; 3514 int64_t ret, ret2; 3515 3516 length = bdrv_getlength(bs); 3517 if (length < 0) { 3518 return length; 3519 } 3520 3521 if (sector_num >= (length >> BDRV_SECTOR_BITS)) { 3522 *pnum = 0; 3523 return 0; 3524 } 3525 3526 n = bs->total_sectors - sector_num; 3527 if (n < nb_sectors) { 3528 nb_sectors = n; 3529 } 3530 3531 if (!bs->drv->bdrv_co_get_block_status) { 3532 *pnum = nb_sectors; 3533 ret = BDRV_BLOCK_DATA; 3534 if (bs->drv->protocol_name) { 3535 ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); 3536 } 3537 return ret; 3538 } 3539 3540 ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); 3541 if (ret < 0) { 3542 *pnum = 0; 3543 return ret; 3544 } 3545 3546 if (ret & BDRV_BLOCK_RAW) { 3547 assert(ret & BDRV_BLOCK_OFFSET_VALID); 3548 return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3549 *pnum, pnum); 3550 } 3551 3552 if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { 3553 if (bdrv_unallocated_blocks_are_zero(bs)) { 3554 ret |= BDRV_BLOCK_ZERO; 3555 } else if (bs->backing_hd) { 3556 BlockDriverState *bs2 = bs->backing_hd; 3557 int64_t length2 = bdrv_getlength(bs2); 3558 if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) { 3559 ret |= BDRV_BLOCK_ZERO; 3560 } 3561 } 3562 } 3563 3564 if (bs->file && 3565 (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && 3566 (ret & BDRV_BLOCK_OFFSET_VALID)) { 3567 ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3568 *pnum, pnum); 3569 if (ret2 >= 0) { 3570 /* Ignore errors. This is just providing extra information, it 3571 * is useful but not necessary. 3572 */ 3573 ret |= (ret2 & BDRV_BLOCK_ZERO); 3574 } 3575 } 3576 3577 return ret; 3578 } 3579 3580 /* Coroutine wrapper for bdrv_get_block_status() */ 3581 static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque) 3582 { 3583 BdrvCoGetBlockStatusData *data = opaque; 3584 BlockDriverState *bs = data->bs; 3585 3586 data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors, 3587 data->pnum); 3588 data->done = true; 3589 } 3590 3591 /* 3592 * Synchronous wrapper around bdrv_co_get_block_status(). 3593 * 3594 * See bdrv_co_get_block_status() for details. 3595 */ 3596 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, 3597 int nb_sectors, int *pnum) 3598 { 3599 Coroutine *co; 3600 BdrvCoGetBlockStatusData data = { 3601 .bs = bs, 3602 .sector_num = sector_num, 3603 .nb_sectors = nb_sectors, 3604 .pnum = pnum, 3605 .done = false, 3606 }; 3607 3608 if (qemu_in_coroutine()) { 3609 /* Fast-path if already in coroutine context */ 3610 bdrv_get_block_status_co_entry(&data); 3611 } else { 3612 co = qemu_coroutine_create(bdrv_get_block_status_co_entry); 3613 qemu_coroutine_enter(co, &data); 3614 while (!data.done) { 3615 qemu_aio_wait(); 3616 } 3617 } 3618 return data.ret; 3619 } 3620 3621 int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, 3622 int nb_sectors, int *pnum) 3623 { 3624 int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); 3625 if (ret < 0) { 3626 return ret; 3627 } 3628 return 3629 (ret & BDRV_BLOCK_DATA) || 3630 ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); 3631 } 3632 3633 /* 3634 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] 3635 * 3636 * Return true if the given sector is allocated in any image between 3637 * BASE and TOP (inclusive). BASE can be NULL to check if the given 3638 * sector is allocated in any image of the chain. Return false otherwise. 3639 * 3640 * 'pnum' is set to the number of sectors (including and immediately following 3641 * the specified sector) that are known to be in the same 3642 * allocated/unallocated state. 3643 * 3644 */ 3645 int bdrv_is_allocated_above(BlockDriverState *top, 3646 BlockDriverState *base, 3647 int64_t sector_num, 3648 int nb_sectors, int *pnum) 3649 { 3650 BlockDriverState *intermediate; 3651 int ret, n = nb_sectors; 3652 3653 intermediate = top; 3654 while (intermediate && intermediate != base) { 3655 int pnum_inter; 3656 ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors, 3657 &pnum_inter); 3658 if (ret < 0) { 3659 return ret; 3660 } else if (ret) { 3661 *pnum = pnum_inter; 3662 return 1; 3663 } 3664 3665 /* 3666 * [sector_num, nb_sectors] is unallocated on top but intermediate 3667 * might have 3668 * 3669 * [sector_num+x, nr_sectors] allocated. 3670 */ 3671 if (n > pnum_inter && 3672 (intermediate == top || 3673 sector_num + pnum_inter < intermediate->total_sectors)) { 3674 n = pnum_inter; 3675 } 3676 3677 intermediate = intermediate->backing_hd; 3678 } 3679 3680 *pnum = n; 3681 return 0; 3682 } 3683 3684 const char *bdrv_get_encrypted_filename(BlockDriverState *bs) 3685 { 3686 if (bs->backing_hd && bs->backing_hd->encrypted) 3687 return bs->backing_file; 3688 else if (bs->encrypted) 3689 return bs->filename; 3690 else 3691 return NULL; 3692 } 3693 3694 void bdrv_get_backing_filename(BlockDriverState *bs, 3695 char *filename, int filename_size) 3696 { 3697 pstrcpy(filename, filename_size, bs->backing_file); 3698 } 3699 3700 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num, 3701 const uint8_t *buf, int nb_sectors) 3702 { 3703 BlockDriver *drv = bs->drv; 3704 if (!drv) 3705 return -ENOMEDIUM; 3706 if (!drv->bdrv_write_compressed) 3707 return -ENOTSUP; 3708 if (bdrv_check_request(bs, sector_num, nb_sectors)) 3709 return -EIO; 3710 3711 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 3712 3713 return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors); 3714 } 3715 3716 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3717 { 3718 BlockDriver *drv = bs->drv; 3719 if (!drv) 3720 return -ENOMEDIUM; 3721 if (!drv->bdrv_get_info) 3722 return -ENOTSUP; 3723 memset(bdi, 0, sizeof(*bdi)); 3724 return drv->bdrv_get_info(bs, bdi); 3725 } 3726 3727 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) 3728 { 3729 BlockDriver *drv = bs->drv; 3730 if (drv && drv->bdrv_get_specific_info) { 3731 return drv->bdrv_get_specific_info(bs); 3732 } 3733 return NULL; 3734 } 3735 3736 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 3737 int64_t pos, int size) 3738 { 3739 QEMUIOVector qiov; 3740 struct iovec iov = { 3741 .iov_base = (void *) buf, 3742 .iov_len = size, 3743 }; 3744 3745 qemu_iovec_init_external(&qiov, &iov, 1); 3746 return bdrv_writev_vmstate(bs, &qiov, pos); 3747 } 3748 3749 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) 3750 { 3751 BlockDriver *drv = bs->drv; 3752 3753 if (!drv) { 3754 return -ENOMEDIUM; 3755 } else if (drv->bdrv_save_vmstate) { 3756 return drv->bdrv_save_vmstate(bs, qiov, pos); 3757 } else if (bs->file) { 3758 return bdrv_writev_vmstate(bs->file, qiov, pos); 3759 } 3760 3761 return -ENOTSUP; 3762 } 3763 3764 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 3765 int64_t pos, int size) 3766 { 3767 BlockDriver *drv = bs->drv; 3768 if (!drv) 3769 return -ENOMEDIUM; 3770 if (drv->bdrv_load_vmstate) 3771 return drv->bdrv_load_vmstate(bs, buf, pos, size); 3772 if (bs->file) 3773 return bdrv_load_vmstate(bs->file, buf, pos, size); 3774 return -ENOTSUP; 3775 } 3776 3777 void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event) 3778 { 3779 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { 3780 return; 3781 } 3782 3783 bs->drv->bdrv_debug_event(bs, event); 3784 } 3785 3786 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, 3787 const char *tag) 3788 { 3789 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { 3790 bs = bs->file; 3791 } 3792 3793 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { 3794 return bs->drv->bdrv_debug_breakpoint(bs, event, tag); 3795 } 3796 3797 return -ENOTSUP; 3798 } 3799 3800 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) 3801 { 3802 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { 3803 bs = bs->file; 3804 } 3805 3806 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { 3807 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); 3808 } 3809 3810 return -ENOTSUP; 3811 } 3812 3813 int bdrv_debug_resume(BlockDriverState *bs, const char *tag) 3814 { 3815 while (bs && bs->drv && !bs->drv->bdrv_debug_resume) { 3816 bs = bs->file; 3817 } 3818 3819 if (bs && bs->drv && bs->drv->bdrv_debug_resume) { 3820 return bs->drv->bdrv_debug_resume(bs, tag); 3821 } 3822 3823 return -ENOTSUP; 3824 } 3825 3826 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) 3827 { 3828 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { 3829 bs = bs->file; 3830 } 3831 3832 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { 3833 return bs->drv->bdrv_debug_is_suspended(bs, tag); 3834 } 3835 3836 return false; 3837 } 3838 3839 int bdrv_is_snapshot(BlockDriverState *bs) 3840 { 3841 return !!(bs->open_flags & BDRV_O_SNAPSHOT); 3842 } 3843 3844 /* backing_file can either be relative, or absolute, or a protocol. If it is 3845 * relative, it must be relative to the chain. So, passing in bs->filename 3846 * from a BDS as backing_file should not be done, as that may be relative to 3847 * the CWD rather than the chain. */ 3848 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 3849 const char *backing_file) 3850 { 3851 char *filename_full = NULL; 3852 char *backing_file_full = NULL; 3853 char *filename_tmp = NULL; 3854 int is_protocol = 0; 3855 BlockDriverState *curr_bs = NULL; 3856 BlockDriverState *retval = NULL; 3857 3858 if (!bs || !bs->drv || !backing_file) { 3859 return NULL; 3860 } 3861 3862 filename_full = g_malloc(PATH_MAX); 3863 backing_file_full = g_malloc(PATH_MAX); 3864 filename_tmp = g_malloc(PATH_MAX); 3865 3866 is_protocol = path_has_protocol(backing_file); 3867 3868 for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) { 3869 3870 /* If either of the filename paths is actually a protocol, then 3871 * compare unmodified paths; otherwise make paths relative */ 3872 if (is_protocol || path_has_protocol(curr_bs->backing_file)) { 3873 if (strcmp(backing_file, curr_bs->backing_file) == 0) { 3874 retval = curr_bs->backing_hd; 3875 break; 3876 } 3877 } else { 3878 /* If not an absolute filename path, make it relative to the current 3879 * image's filename path */ 3880 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3881 backing_file); 3882 3883 /* We are going to compare absolute pathnames */ 3884 if (!realpath(filename_tmp, filename_full)) { 3885 continue; 3886 } 3887 3888 /* We need to make sure the backing filename we are comparing against 3889 * is relative to the current image filename (or absolute) */ 3890 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 3891 curr_bs->backing_file); 3892 3893 if (!realpath(filename_tmp, backing_file_full)) { 3894 continue; 3895 } 3896 3897 if (strcmp(backing_file_full, filename_full) == 0) { 3898 retval = curr_bs->backing_hd; 3899 break; 3900 } 3901 } 3902 } 3903 3904 g_free(filename_full); 3905 g_free(backing_file_full); 3906 g_free(filename_tmp); 3907 return retval; 3908 } 3909 3910 int bdrv_get_backing_file_depth(BlockDriverState *bs) 3911 { 3912 if (!bs->drv) { 3913 return 0; 3914 } 3915 3916 if (!bs->backing_hd) { 3917 return 0; 3918 } 3919 3920 return 1 + bdrv_get_backing_file_depth(bs->backing_hd); 3921 } 3922 3923 BlockDriverState *bdrv_find_base(BlockDriverState *bs) 3924 { 3925 BlockDriverState *curr_bs = NULL; 3926 3927 if (!bs) { 3928 return NULL; 3929 } 3930 3931 curr_bs = bs; 3932 3933 while (curr_bs->backing_hd) { 3934 curr_bs = curr_bs->backing_hd; 3935 } 3936 return curr_bs; 3937 } 3938 3939 /**************************************************************/ 3940 /* async I/Os */ 3941 3942 BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, 3943 QEMUIOVector *qiov, int nb_sectors, 3944 BlockDriverCompletionFunc *cb, void *opaque) 3945 { 3946 trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); 3947 3948 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 3949 cb, opaque, false); 3950 } 3951 3952 BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, 3953 QEMUIOVector *qiov, int nb_sectors, 3954 BlockDriverCompletionFunc *cb, void *opaque) 3955 { 3956 trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); 3957 3958 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 3959 cb, opaque, true); 3960 } 3961 3962 BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, 3963 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags, 3964 BlockDriverCompletionFunc *cb, void *opaque) 3965 { 3966 trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque); 3967 3968 return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors, 3969 BDRV_REQ_ZERO_WRITE | flags, 3970 cb, opaque, true); 3971 } 3972 3973 3974 typedef struct MultiwriteCB { 3975 int error; 3976 int num_requests; 3977 int num_callbacks; 3978 struct { 3979 BlockDriverCompletionFunc *cb; 3980 void *opaque; 3981 QEMUIOVector *free_qiov; 3982 } callbacks[]; 3983 } MultiwriteCB; 3984 3985 static void multiwrite_user_cb(MultiwriteCB *mcb) 3986 { 3987 int i; 3988 3989 for (i = 0; i < mcb->num_callbacks; i++) { 3990 mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error); 3991 if (mcb->callbacks[i].free_qiov) { 3992 qemu_iovec_destroy(mcb->callbacks[i].free_qiov); 3993 } 3994 g_free(mcb->callbacks[i].free_qiov); 3995 } 3996 } 3997 3998 static void multiwrite_cb(void *opaque, int ret) 3999 { 4000 MultiwriteCB *mcb = opaque; 4001 4002 trace_multiwrite_cb(mcb, ret); 4003 4004 if (ret < 0 && !mcb->error) { 4005 mcb->error = ret; 4006 } 4007 4008 mcb->num_requests--; 4009 if (mcb->num_requests == 0) { 4010 multiwrite_user_cb(mcb); 4011 g_free(mcb); 4012 } 4013 } 4014 4015 static int multiwrite_req_compare(const void *a, const void *b) 4016 { 4017 const BlockRequest *req1 = a, *req2 = b; 4018 4019 /* 4020 * Note that we can't simply subtract req2->sector from req1->sector 4021 * here as that could overflow the return value. 4022 */ 4023 if (req1->sector > req2->sector) { 4024 return 1; 4025 } else if (req1->sector < req2->sector) { 4026 return -1; 4027 } else { 4028 return 0; 4029 } 4030 } 4031 4032 /* 4033 * Takes a bunch of requests and tries to merge them. Returns the number of 4034 * requests that remain after merging. 4035 */ 4036 static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, 4037 int num_reqs, MultiwriteCB *mcb) 4038 { 4039 int i, outidx; 4040 4041 // Sort requests by start sector 4042 qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare); 4043 4044 // Check if adjacent requests touch the same clusters. If so, combine them, 4045 // filling up gaps with zero sectors. 4046 outidx = 0; 4047 for (i = 1; i < num_reqs; i++) { 4048 int merge = 0; 4049 int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors; 4050 4051 // Handle exactly sequential writes and overlapping writes. 4052 if (reqs[i].sector <= oldreq_last) { 4053 merge = 1; 4054 } 4055 4056 if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { 4057 merge = 0; 4058 } 4059 4060 if (merge) { 4061 size_t size; 4062 QEMUIOVector *qiov = g_malloc0(sizeof(*qiov)); 4063 qemu_iovec_init(qiov, 4064 reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1); 4065 4066 // Add the first request to the merged one. If the requests are 4067 // overlapping, drop the last sectors of the first request. 4068 size = (reqs[i].sector - reqs[outidx].sector) << 9; 4069 qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size); 4070 4071 // We should need to add any zeros between the two requests 4072 assert (reqs[i].sector <= oldreq_last); 4073 4074 // Add the second request 4075 qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size); 4076 4077 reqs[outidx].nb_sectors = qiov->size >> 9; 4078 reqs[outidx].qiov = qiov; 4079 4080 mcb->callbacks[i].free_qiov = reqs[outidx].qiov; 4081 } else { 4082 outidx++; 4083 reqs[outidx].sector = reqs[i].sector; 4084 reqs[outidx].nb_sectors = reqs[i].nb_sectors; 4085 reqs[outidx].qiov = reqs[i].qiov; 4086 } 4087 } 4088 4089 return outidx + 1; 4090 } 4091 4092 /* 4093 * Submit multiple AIO write requests at once. 4094 * 4095 * On success, the function returns 0 and all requests in the reqs array have 4096 * been submitted. In error case this function returns -1, and any of the 4097 * requests may or may not be submitted yet. In particular, this means that the 4098 * callback will be called for some of the requests, for others it won't. The 4099 * caller must check the error field of the BlockRequest to wait for the right 4100 * callbacks (if error != 0, no callback will be called). 4101 * 4102 * The implementation may modify the contents of the reqs array, e.g. to merge 4103 * requests. However, the fields opaque and error are left unmodified as they 4104 * are used to signal failure for a single request to the caller. 4105 */ 4106 int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) 4107 { 4108 MultiwriteCB *mcb; 4109 int i; 4110 4111 /* don't submit writes if we don't have a medium */ 4112 if (bs->drv == NULL) { 4113 for (i = 0; i < num_reqs; i++) { 4114 reqs[i].error = -ENOMEDIUM; 4115 } 4116 return -1; 4117 } 4118 4119 if (num_reqs == 0) { 4120 return 0; 4121 } 4122 4123 // Create MultiwriteCB structure 4124 mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks)); 4125 mcb->num_requests = 0; 4126 mcb->num_callbacks = num_reqs; 4127 4128 for (i = 0; i < num_reqs; i++) { 4129 mcb->callbacks[i].cb = reqs[i].cb; 4130 mcb->callbacks[i].opaque = reqs[i].opaque; 4131 } 4132 4133 // Check for mergable requests 4134 num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb); 4135 4136 trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs); 4137 4138 /* Run the aio requests. */ 4139 mcb->num_requests = num_reqs; 4140 for (i = 0; i < num_reqs; i++) { 4141 bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov, 4142 reqs[i].nb_sectors, reqs[i].flags, 4143 multiwrite_cb, mcb, 4144 true); 4145 } 4146 4147 return 0; 4148 } 4149 4150 void bdrv_aio_cancel(BlockDriverAIOCB *acb) 4151 { 4152 acb->aiocb_info->cancel(acb); 4153 } 4154 4155 /**************************************************************/ 4156 /* async block device emulation */ 4157 4158 typedef struct BlockDriverAIOCBSync { 4159 BlockDriverAIOCB common; 4160 QEMUBH *bh; 4161 int ret; 4162 /* vector translation state */ 4163 QEMUIOVector *qiov; 4164 uint8_t *bounce; 4165 int is_write; 4166 } BlockDriverAIOCBSync; 4167 4168 static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb) 4169 { 4170 BlockDriverAIOCBSync *acb = 4171 container_of(blockacb, BlockDriverAIOCBSync, common); 4172 qemu_bh_delete(acb->bh); 4173 acb->bh = NULL; 4174 qemu_aio_release(acb); 4175 } 4176 4177 static const AIOCBInfo bdrv_em_aiocb_info = { 4178 .aiocb_size = sizeof(BlockDriverAIOCBSync), 4179 .cancel = bdrv_aio_cancel_em, 4180 }; 4181 4182 static void bdrv_aio_bh_cb(void *opaque) 4183 { 4184 BlockDriverAIOCBSync *acb = opaque; 4185 4186 if (!acb->is_write) 4187 qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size); 4188 qemu_vfree(acb->bounce); 4189 acb->common.cb(acb->common.opaque, acb->ret); 4190 qemu_bh_delete(acb->bh); 4191 acb->bh = NULL; 4192 qemu_aio_release(acb); 4193 } 4194 4195 static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs, 4196 int64_t sector_num, 4197 QEMUIOVector *qiov, 4198 int nb_sectors, 4199 BlockDriverCompletionFunc *cb, 4200 void *opaque, 4201 int is_write) 4202 4203 { 4204 BlockDriverAIOCBSync *acb; 4205 4206 acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque); 4207 acb->is_write = is_write; 4208 acb->qiov = qiov; 4209 acb->bounce = qemu_blockalign(bs, qiov->size); 4210 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb); 4211 4212 if (is_write) { 4213 qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); 4214 acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors); 4215 } else { 4216 acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors); 4217 } 4218 4219 qemu_bh_schedule(acb->bh); 4220 4221 return &acb->common; 4222 } 4223 4224 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, 4225 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 4226 BlockDriverCompletionFunc *cb, void *opaque) 4227 { 4228 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 4229 } 4230 4231 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, 4232 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 4233 BlockDriverCompletionFunc *cb, void *opaque) 4234 { 4235 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); 4236 } 4237 4238 4239 typedef struct BlockDriverAIOCBCoroutine { 4240 BlockDriverAIOCB common; 4241 BlockRequest req; 4242 bool is_write; 4243 bool *done; 4244 QEMUBH* bh; 4245 } BlockDriverAIOCBCoroutine; 4246 4247 static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb) 4248 { 4249 BlockDriverAIOCBCoroutine *acb = 4250 container_of(blockacb, BlockDriverAIOCBCoroutine, common); 4251 bool done = false; 4252 4253 acb->done = &done; 4254 while (!done) { 4255 qemu_aio_wait(); 4256 } 4257 } 4258 4259 static const AIOCBInfo bdrv_em_co_aiocb_info = { 4260 .aiocb_size = sizeof(BlockDriverAIOCBCoroutine), 4261 .cancel = bdrv_aio_co_cancel_em, 4262 }; 4263 4264 static void bdrv_co_em_bh(void *opaque) 4265 { 4266 BlockDriverAIOCBCoroutine *acb = opaque; 4267 4268 acb->common.cb(acb->common.opaque, acb->req.error); 4269 4270 if (acb->done) { 4271 *acb->done = true; 4272 } 4273 4274 qemu_bh_delete(acb->bh); 4275 qemu_aio_release(acb); 4276 } 4277 4278 /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ 4279 static void coroutine_fn bdrv_co_do_rw(void *opaque) 4280 { 4281 BlockDriverAIOCBCoroutine *acb = opaque; 4282 BlockDriverState *bs = acb->common.bs; 4283 4284 if (!acb->is_write) { 4285 acb->req.error = bdrv_co_do_readv(bs, acb->req.sector, 4286 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4287 } else { 4288 acb->req.error = bdrv_co_do_writev(bs, acb->req.sector, 4289 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4290 } 4291 4292 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4293 qemu_bh_schedule(acb->bh); 4294 } 4295 4296 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, 4297 int64_t sector_num, 4298 QEMUIOVector *qiov, 4299 int nb_sectors, 4300 BdrvRequestFlags flags, 4301 BlockDriverCompletionFunc *cb, 4302 void *opaque, 4303 bool is_write) 4304 { 4305 Coroutine *co; 4306 BlockDriverAIOCBCoroutine *acb; 4307 4308 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4309 acb->req.sector = sector_num; 4310 acb->req.nb_sectors = nb_sectors; 4311 acb->req.qiov = qiov; 4312 acb->req.flags = flags; 4313 acb->is_write = is_write; 4314 acb->done = NULL; 4315 4316 co = qemu_coroutine_create(bdrv_co_do_rw); 4317 qemu_coroutine_enter(co, acb); 4318 4319 return &acb->common; 4320 } 4321 4322 static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque) 4323 { 4324 BlockDriverAIOCBCoroutine *acb = opaque; 4325 BlockDriverState *bs = acb->common.bs; 4326 4327 acb->req.error = bdrv_co_flush(bs); 4328 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4329 qemu_bh_schedule(acb->bh); 4330 } 4331 4332 BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, 4333 BlockDriverCompletionFunc *cb, void *opaque) 4334 { 4335 trace_bdrv_aio_flush(bs, opaque); 4336 4337 Coroutine *co; 4338 BlockDriverAIOCBCoroutine *acb; 4339 4340 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4341 acb->done = NULL; 4342 4343 co = qemu_coroutine_create(bdrv_aio_flush_co_entry); 4344 qemu_coroutine_enter(co, acb); 4345 4346 return &acb->common; 4347 } 4348 4349 static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque) 4350 { 4351 BlockDriverAIOCBCoroutine *acb = opaque; 4352 BlockDriverState *bs = acb->common.bs; 4353 4354 acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors); 4355 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4356 qemu_bh_schedule(acb->bh); 4357 } 4358 4359 BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs, 4360 int64_t sector_num, int nb_sectors, 4361 BlockDriverCompletionFunc *cb, void *opaque) 4362 { 4363 Coroutine *co; 4364 BlockDriverAIOCBCoroutine *acb; 4365 4366 trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque); 4367 4368 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4369 acb->req.sector = sector_num; 4370 acb->req.nb_sectors = nb_sectors; 4371 acb->done = NULL; 4372 co = qemu_coroutine_create(bdrv_aio_discard_co_entry); 4373 qemu_coroutine_enter(co, acb); 4374 4375 return &acb->common; 4376 } 4377 4378 void bdrv_init(void) 4379 { 4380 module_call_init(MODULE_INIT_BLOCK); 4381 } 4382 4383 void bdrv_init_with_whitelist(void) 4384 { 4385 use_bdrv_whitelist = 1; 4386 bdrv_init(); 4387 } 4388 4389 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, 4390 BlockDriverCompletionFunc *cb, void *opaque) 4391 { 4392 BlockDriverAIOCB *acb; 4393 4394 acb = g_slice_alloc(aiocb_info->aiocb_size); 4395 acb->aiocb_info = aiocb_info; 4396 acb->bs = bs; 4397 acb->cb = cb; 4398 acb->opaque = opaque; 4399 return acb; 4400 } 4401 4402 void qemu_aio_release(void *p) 4403 { 4404 BlockDriverAIOCB *acb = p; 4405 g_slice_free1(acb->aiocb_info->aiocb_size, acb); 4406 } 4407 4408 /**************************************************************/ 4409 /* Coroutine block device emulation */ 4410 4411 typedef struct CoroutineIOCompletion { 4412 Coroutine *coroutine; 4413 int ret; 4414 } CoroutineIOCompletion; 4415 4416 static void bdrv_co_io_em_complete(void *opaque, int ret) 4417 { 4418 CoroutineIOCompletion *co = opaque; 4419 4420 co->ret = ret; 4421 qemu_coroutine_enter(co->coroutine, NULL); 4422 } 4423 4424 static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num, 4425 int nb_sectors, QEMUIOVector *iov, 4426 bool is_write) 4427 { 4428 CoroutineIOCompletion co = { 4429 .coroutine = qemu_coroutine_self(), 4430 }; 4431 BlockDriverAIOCB *acb; 4432 4433 if (is_write) { 4434 acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors, 4435 bdrv_co_io_em_complete, &co); 4436 } else { 4437 acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors, 4438 bdrv_co_io_em_complete, &co); 4439 } 4440 4441 trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb); 4442 if (!acb) { 4443 return -EIO; 4444 } 4445 qemu_coroutine_yield(); 4446 4447 return co.ret; 4448 } 4449 4450 static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, 4451 int64_t sector_num, int nb_sectors, 4452 QEMUIOVector *iov) 4453 { 4454 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false); 4455 } 4456 4457 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, 4458 int64_t sector_num, int nb_sectors, 4459 QEMUIOVector *iov) 4460 { 4461 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true); 4462 } 4463 4464 static void coroutine_fn bdrv_flush_co_entry(void *opaque) 4465 { 4466 RwCo *rwco = opaque; 4467 4468 rwco->ret = bdrv_co_flush(rwco->bs); 4469 } 4470 4471 int coroutine_fn bdrv_co_flush(BlockDriverState *bs) 4472 { 4473 int ret; 4474 4475 if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { 4476 return 0; 4477 } 4478 4479 /* Write back cached data to the OS even with cache=unsafe */ 4480 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); 4481 if (bs->drv->bdrv_co_flush_to_os) { 4482 ret = bs->drv->bdrv_co_flush_to_os(bs); 4483 if (ret < 0) { 4484 return ret; 4485 } 4486 } 4487 4488 /* But don't actually force it to the disk with cache=unsafe */ 4489 if (bs->open_flags & BDRV_O_NO_FLUSH) { 4490 goto flush_parent; 4491 } 4492 4493 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); 4494 if (bs->drv->bdrv_co_flush_to_disk) { 4495 ret = bs->drv->bdrv_co_flush_to_disk(bs); 4496 } else if (bs->drv->bdrv_aio_flush) { 4497 BlockDriverAIOCB *acb; 4498 CoroutineIOCompletion co = { 4499 .coroutine = qemu_coroutine_self(), 4500 }; 4501 4502 acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); 4503 if (acb == NULL) { 4504 ret = -EIO; 4505 } else { 4506 qemu_coroutine_yield(); 4507 ret = co.ret; 4508 } 4509 } else { 4510 /* 4511 * Some block drivers always operate in either writethrough or unsafe 4512 * mode and don't support bdrv_flush therefore. Usually qemu doesn't 4513 * know how the server works (because the behaviour is hardcoded or 4514 * depends on server-side configuration), so we can't ensure that 4515 * everything is safe on disk. Returning an error doesn't work because 4516 * that would break guests even if the server operates in writethrough 4517 * mode. 4518 * 4519 * Let's hope the user knows what he's doing. 4520 */ 4521 ret = 0; 4522 } 4523 if (ret < 0) { 4524 return ret; 4525 } 4526 4527 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH 4528 * in the case of cache=unsafe, so there are no useless flushes. 4529 */ 4530 flush_parent: 4531 return bdrv_co_flush(bs->file); 4532 } 4533 4534 void bdrv_invalidate_cache(BlockDriverState *bs) 4535 { 4536 if (bs->drv && bs->drv->bdrv_invalidate_cache) { 4537 bs->drv->bdrv_invalidate_cache(bs); 4538 } 4539 } 4540 4541 void bdrv_invalidate_cache_all(void) 4542 { 4543 BlockDriverState *bs; 4544 4545 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 4546 bdrv_invalidate_cache(bs); 4547 } 4548 } 4549 4550 void bdrv_clear_incoming_migration_all(void) 4551 { 4552 BlockDriverState *bs; 4553 4554 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 4555 bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING); 4556 } 4557 } 4558 4559 int bdrv_flush(BlockDriverState *bs) 4560 { 4561 Coroutine *co; 4562 RwCo rwco = { 4563 .bs = bs, 4564 .ret = NOT_DONE, 4565 }; 4566 4567 if (qemu_in_coroutine()) { 4568 /* Fast-path if already in coroutine context */ 4569 bdrv_flush_co_entry(&rwco); 4570 } else { 4571 co = qemu_coroutine_create(bdrv_flush_co_entry); 4572 qemu_coroutine_enter(co, &rwco); 4573 while (rwco.ret == NOT_DONE) { 4574 qemu_aio_wait(); 4575 } 4576 } 4577 4578 return rwco.ret; 4579 } 4580 4581 static void coroutine_fn bdrv_discard_co_entry(void *opaque) 4582 { 4583 RwCo *rwco = opaque; 4584 4585 rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); 4586 } 4587 4588 /* if no limit is specified in the BlockLimits use a default 4589 * of 32768 512-byte sectors (16 MiB) per request. 4590 */ 4591 #define MAX_DISCARD_DEFAULT 32768 4592 4593 int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, 4594 int nb_sectors) 4595 { 4596 int max_discard; 4597 4598 if (!bs->drv) { 4599 return -ENOMEDIUM; 4600 } else if (bdrv_check_request(bs, sector_num, nb_sectors)) { 4601 return -EIO; 4602 } else if (bs->read_only) { 4603 return -EROFS; 4604 } 4605 4606 bdrv_reset_dirty(bs, sector_num, nb_sectors); 4607 4608 /* Do nothing if disabled. */ 4609 if (!(bs->open_flags & BDRV_O_UNMAP)) { 4610 return 0; 4611 } 4612 4613 if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) { 4614 return 0; 4615 } 4616 4617 max_discard = bs->bl.max_discard ? bs->bl.max_discard : MAX_DISCARD_DEFAULT; 4618 while (nb_sectors > 0) { 4619 int ret; 4620 int num = nb_sectors; 4621 4622 /* align request */ 4623 if (bs->bl.discard_alignment && 4624 num >= bs->bl.discard_alignment && 4625 sector_num % bs->bl.discard_alignment) { 4626 if (num > bs->bl.discard_alignment) { 4627 num = bs->bl.discard_alignment; 4628 } 4629 num -= sector_num % bs->bl.discard_alignment; 4630 } 4631 4632 /* limit request size */ 4633 if (num > max_discard) { 4634 num = max_discard; 4635 } 4636 4637 if (bs->drv->bdrv_co_discard) { 4638 ret = bs->drv->bdrv_co_discard(bs, sector_num, num); 4639 } else { 4640 BlockDriverAIOCB *acb; 4641 CoroutineIOCompletion co = { 4642 .coroutine = qemu_coroutine_self(), 4643 }; 4644 4645 acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, 4646 bdrv_co_io_em_complete, &co); 4647 if (acb == NULL) { 4648 return -EIO; 4649 } else { 4650 qemu_coroutine_yield(); 4651 ret = co.ret; 4652 } 4653 } 4654 if (ret && ret != -ENOTSUP) { 4655 return ret; 4656 } 4657 4658 sector_num += num; 4659 nb_sectors -= num; 4660 } 4661 return 0; 4662 } 4663 4664 int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) 4665 { 4666 Coroutine *co; 4667 RwCo rwco = { 4668 .bs = bs, 4669 .sector_num = sector_num, 4670 .nb_sectors = nb_sectors, 4671 .ret = NOT_DONE, 4672 }; 4673 4674 if (qemu_in_coroutine()) { 4675 /* Fast-path if already in coroutine context */ 4676 bdrv_discard_co_entry(&rwco); 4677 } else { 4678 co = qemu_coroutine_create(bdrv_discard_co_entry); 4679 qemu_coroutine_enter(co, &rwco); 4680 while (rwco.ret == NOT_DONE) { 4681 qemu_aio_wait(); 4682 } 4683 } 4684 4685 return rwco.ret; 4686 } 4687 4688 /**************************************************************/ 4689 /* removable device support */ 4690 4691 /** 4692 * Return TRUE if the media is present 4693 */ 4694 int bdrv_is_inserted(BlockDriverState *bs) 4695 { 4696 BlockDriver *drv = bs->drv; 4697 4698 if (!drv) 4699 return 0; 4700 if (!drv->bdrv_is_inserted) 4701 return 1; 4702 return drv->bdrv_is_inserted(bs); 4703 } 4704 4705 /** 4706 * Return whether the media changed since the last call to this 4707 * function, or -ENOTSUP if we don't know. Most drivers don't know. 4708 */ 4709 int bdrv_media_changed(BlockDriverState *bs) 4710 { 4711 BlockDriver *drv = bs->drv; 4712 4713 if (drv && drv->bdrv_media_changed) { 4714 return drv->bdrv_media_changed(bs); 4715 } 4716 return -ENOTSUP; 4717 } 4718 4719 /** 4720 * If eject_flag is TRUE, eject the media. Otherwise, close the tray 4721 */ 4722 void bdrv_eject(BlockDriverState *bs, bool eject_flag) 4723 { 4724 BlockDriver *drv = bs->drv; 4725 4726 if (drv && drv->bdrv_eject) { 4727 drv->bdrv_eject(bs, eject_flag); 4728 } 4729 4730 if (bs->device_name[0] != '\0') { 4731 bdrv_emit_qmp_eject_event(bs, eject_flag); 4732 } 4733 } 4734 4735 /** 4736 * Lock or unlock the media (if it is locked, the user won't be able 4737 * to eject it manually). 4738 */ 4739 void bdrv_lock_medium(BlockDriverState *bs, bool locked) 4740 { 4741 BlockDriver *drv = bs->drv; 4742 4743 trace_bdrv_lock_medium(bs, locked); 4744 4745 if (drv && drv->bdrv_lock_medium) { 4746 drv->bdrv_lock_medium(bs, locked); 4747 } 4748 } 4749 4750 /* needed for generic scsi interface */ 4751 4752 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf) 4753 { 4754 BlockDriver *drv = bs->drv; 4755 4756 if (drv && drv->bdrv_ioctl) 4757 return drv->bdrv_ioctl(bs, req, buf); 4758 return -ENOTSUP; 4759 } 4760 4761 BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, 4762 unsigned long int req, void *buf, 4763 BlockDriverCompletionFunc *cb, void *opaque) 4764 { 4765 BlockDriver *drv = bs->drv; 4766 4767 if (drv && drv->bdrv_aio_ioctl) 4768 return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque); 4769 return NULL; 4770 } 4771 4772 void bdrv_set_buffer_alignment(BlockDriverState *bs, int align) 4773 { 4774 bs->buffer_alignment = align; 4775 } 4776 4777 void *qemu_blockalign(BlockDriverState *bs, size_t size) 4778 { 4779 return qemu_memalign((bs && bs->buffer_alignment) ? bs->buffer_alignment : 512, size); 4780 } 4781 4782 /* 4783 * Check if all memory in this vector is sector aligned. 4784 */ 4785 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) 4786 { 4787 int i; 4788 4789 for (i = 0; i < qiov->niov; i++) { 4790 if ((uintptr_t) qiov->iov[i].iov_base % bs->buffer_alignment) { 4791 return false; 4792 } 4793 } 4794 4795 return true; 4796 } 4797 4798 BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity) 4799 { 4800 int64_t bitmap_size; 4801 BdrvDirtyBitmap *bitmap; 4802 4803 assert((granularity & (granularity - 1)) == 0); 4804 4805 granularity >>= BDRV_SECTOR_BITS; 4806 assert(granularity); 4807 bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS); 4808 bitmap = g_malloc0(sizeof(BdrvDirtyBitmap)); 4809 bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1); 4810 QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list); 4811 return bitmap; 4812 } 4813 4814 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 4815 { 4816 BdrvDirtyBitmap *bm, *next; 4817 QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { 4818 if (bm == bitmap) { 4819 QLIST_REMOVE(bitmap, list); 4820 hbitmap_free(bitmap->bitmap); 4821 g_free(bitmap); 4822 return; 4823 } 4824 } 4825 } 4826 4827 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs) 4828 { 4829 BdrvDirtyBitmap *bm; 4830 BlockDirtyInfoList *list = NULL; 4831 BlockDirtyInfoList **plist = &list; 4832 4833 QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { 4834 BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo)); 4835 BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList)); 4836 info->count = bdrv_get_dirty_count(bs, bm); 4837 info->granularity = 4838 ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap)); 4839 entry->value = info; 4840 *plist = entry; 4841 plist = &entry->next; 4842 } 4843 4844 return list; 4845 } 4846 4847 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector) 4848 { 4849 if (bitmap) { 4850 return hbitmap_get(bitmap->bitmap, sector); 4851 } else { 4852 return 0; 4853 } 4854 } 4855 4856 void bdrv_dirty_iter_init(BlockDriverState *bs, 4857 BdrvDirtyBitmap *bitmap, HBitmapIter *hbi) 4858 { 4859 hbitmap_iter_init(hbi, bitmap->bitmap, 0); 4860 } 4861 4862 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, 4863 int nr_sectors) 4864 { 4865 BdrvDirtyBitmap *bitmap; 4866 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 4867 hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); 4868 } 4869 } 4870 4871 void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) 4872 { 4873 BdrvDirtyBitmap *bitmap; 4874 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 4875 hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); 4876 } 4877 } 4878 4879 int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 4880 { 4881 return hbitmap_count(bitmap->bitmap); 4882 } 4883 4884 /* Get a reference to bs */ 4885 void bdrv_ref(BlockDriverState *bs) 4886 { 4887 bs->refcnt++; 4888 } 4889 4890 /* Release a previously grabbed reference to bs. 4891 * If after releasing, reference count is zero, the BlockDriverState is 4892 * deleted. */ 4893 void bdrv_unref(BlockDriverState *bs) 4894 { 4895 assert(bs->refcnt > 0); 4896 if (--bs->refcnt == 0) { 4897 bdrv_delete(bs); 4898 } 4899 } 4900 4901 void bdrv_set_in_use(BlockDriverState *bs, int in_use) 4902 { 4903 assert(bs->in_use != in_use); 4904 bs->in_use = in_use; 4905 } 4906 4907 int bdrv_in_use(BlockDriverState *bs) 4908 { 4909 return bs->in_use; 4910 } 4911 4912 void bdrv_iostatus_enable(BlockDriverState *bs) 4913 { 4914 bs->iostatus_enabled = true; 4915 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 4916 } 4917 4918 /* The I/O status is only enabled if the drive explicitly 4919 * enables it _and_ the VM is configured to stop on errors */ 4920 bool bdrv_iostatus_is_enabled(const BlockDriverState *bs) 4921 { 4922 return (bs->iostatus_enabled && 4923 (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC || 4924 bs->on_write_error == BLOCKDEV_ON_ERROR_STOP || 4925 bs->on_read_error == BLOCKDEV_ON_ERROR_STOP)); 4926 } 4927 4928 void bdrv_iostatus_disable(BlockDriverState *bs) 4929 { 4930 bs->iostatus_enabled = false; 4931 } 4932 4933 void bdrv_iostatus_reset(BlockDriverState *bs) 4934 { 4935 if (bdrv_iostatus_is_enabled(bs)) { 4936 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 4937 if (bs->job) { 4938 block_job_iostatus_reset(bs->job); 4939 } 4940 } 4941 } 4942 4943 void bdrv_iostatus_set_err(BlockDriverState *bs, int error) 4944 { 4945 assert(bdrv_iostatus_is_enabled(bs)); 4946 if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 4947 bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : 4948 BLOCK_DEVICE_IO_STATUS_FAILED; 4949 } 4950 } 4951 4952 void 4953 bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes, 4954 enum BlockAcctType type) 4955 { 4956 assert(type < BDRV_MAX_IOTYPE); 4957 4958 cookie->bytes = bytes; 4959 cookie->start_time_ns = get_clock(); 4960 cookie->type = type; 4961 } 4962 4963 void 4964 bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie) 4965 { 4966 assert(cookie->type < BDRV_MAX_IOTYPE); 4967 4968 bs->nr_bytes[cookie->type] += cookie->bytes; 4969 bs->nr_ops[cookie->type]++; 4970 bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns; 4971 } 4972 4973 void bdrv_img_create(const char *filename, const char *fmt, 4974 const char *base_filename, const char *base_fmt, 4975 char *options, uint64_t img_size, int flags, 4976 Error **errp, bool quiet) 4977 { 4978 QEMUOptionParameter *param = NULL, *create_options = NULL; 4979 QEMUOptionParameter *backing_fmt, *backing_file, *size; 4980 BlockDriver *drv, *proto_drv; 4981 BlockDriver *backing_drv = NULL; 4982 Error *local_err = NULL; 4983 int ret = 0; 4984 4985 /* Find driver and parse its options */ 4986 drv = bdrv_find_format(fmt); 4987 if (!drv) { 4988 error_setg(errp, "Unknown file format '%s'", fmt); 4989 return; 4990 } 4991 4992 proto_drv = bdrv_find_protocol(filename, true); 4993 if (!proto_drv) { 4994 error_setg(errp, "Unknown protocol '%s'", filename); 4995 return; 4996 } 4997 4998 create_options = append_option_parameters(create_options, 4999 drv->create_options); 5000 create_options = append_option_parameters(create_options, 5001 proto_drv->create_options); 5002 5003 /* Create parameter list with default values */ 5004 param = parse_option_parameters("", create_options, param); 5005 5006 set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size); 5007 5008 /* Parse -o options */ 5009 if (options) { 5010 param = parse_option_parameters(options, create_options, param); 5011 if (param == NULL) { 5012 error_setg(errp, "Invalid options for file format '%s'.", fmt); 5013 goto out; 5014 } 5015 } 5016 5017 if (base_filename) { 5018 if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE, 5019 base_filename)) { 5020 error_setg(errp, "Backing file not supported for file format '%s'", 5021 fmt); 5022 goto out; 5023 } 5024 } 5025 5026 if (base_fmt) { 5027 if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) { 5028 error_setg(errp, "Backing file format not supported for file " 5029 "format '%s'", fmt); 5030 goto out; 5031 } 5032 } 5033 5034 backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); 5035 if (backing_file && backing_file->value.s) { 5036 if (!strcmp(filename, backing_file->value.s)) { 5037 error_setg(errp, "Error: Trying to create an image with the " 5038 "same filename as the backing file"); 5039 goto out; 5040 } 5041 } 5042 5043 backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT); 5044 if (backing_fmt && backing_fmt->value.s) { 5045 backing_drv = bdrv_find_format(backing_fmt->value.s); 5046 if (!backing_drv) { 5047 error_setg(errp, "Unknown backing file format '%s'", 5048 backing_fmt->value.s); 5049 goto out; 5050 } 5051 } 5052 5053 // The size for the image must always be specified, with one exception: 5054 // If we are using a backing file, we can obtain the size from there 5055 size = get_option_parameter(param, BLOCK_OPT_SIZE); 5056 if (size && size->value.n == -1) { 5057 if (backing_file && backing_file->value.s) { 5058 BlockDriverState *bs; 5059 uint64_t size; 5060 char buf[32]; 5061 int back_flags; 5062 5063 /* backing files always opened read-only */ 5064 back_flags = 5065 flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 5066 5067 bs = bdrv_new(""); 5068 5069 ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags, 5070 backing_drv, &local_err); 5071 if (ret < 0) { 5072 error_setg_errno(errp, -ret, "Could not open '%s': %s", 5073 backing_file->value.s, 5074 error_get_pretty(local_err)); 5075 error_free(local_err); 5076 local_err = NULL; 5077 bdrv_unref(bs); 5078 goto out; 5079 } 5080 bdrv_get_geometry(bs, &size); 5081 size *= 512; 5082 5083 snprintf(buf, sizeof(buf), "%" PRId64, size); 5084 set_option_parameter(param, BLOCK_OPT_SIZE, buf); 5085 5086 bdrv_unref(bs); 5087 } else { 5088 error_setg(errp, "Image creation needs a size parameter"); 5089 goto out; 5090 } 5091 } 5092 5093 if (!quiet) { 5094 printf("Formatting '%s', fmt=%s ", filename, fmt); 5095 print_option_parameters(param); 5096 puts(""); 5097 } 5098 ret = bdrv_create(drv, filename, param, &local_err); 5099 if (ret == -EFBIG) { 5100 /* This is generally a better message than whatever the driver would 5101 * deliver (especially because of the cluster_size_hint), since that 5102 * is most probably not much different from "image too large". */ 5103 const char *cluster_size_hint = ""; 5104 if (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) { 5105 cluster_size_hint = " (try using a larger cluster size)"; 5106 } 5107 error_setg(errp, "The image size is too large for file format '%s'" 5108 "%s", fmt, cluster_size_hint); 5109 error_free(local_err); 5110 local_err = NULL; 5111 } 5112 5113 out: 5114 free_option_parameters(create_options); 5115 free_option_parameters(param); 5116 5117 if (error_is_set(&local_err)) { 5118 error_propagate(errp, local_err); 5119 } 5120 } 5121 5122 AioContext *bdrv_get_aio_context(BlockDriverState *bs) 5123 { 5124 /* Currently BlockDriverState always uses the main loop AioContext */ 5125 return qemu_get_aio_context(); 5126 } 5127 5128 void bdrv_add_before_write_notifier(BlockDriverState *bs, 5129 NotifierWithReturn *notifier) 5130 { 5131 notifier_with_return_list_add(&bs->before_write_notifiers, notifier); 5132 } 5133 5134 int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options) 5135 { 5136 if (bs->drv->bdrv_amend_options == NULL) { 5137 return -ENOTSUP; 5138 } 5139 return bs->drv->bdrv_amend_options(bs, options); 5140 } 5141 5142 /* Used to recurse on single child block filters. 5143 * Single child block filter will store their child in bs->file. 5144 */ 5145 bool bdrv_generic_is_first_non_filter(BlockDriverState *bs, 5146 BlockDriverState *candidate) 5147 { 5148 if (!bs->drv) { 5149 return false; 5150 } 5151 5152 if (!bs->drv->authorizations[BS_IS_A_FILTER]) { 5153 if (bs == candidate) { 5154 return true; 5155 } else { 5156 return false; 5157 } 5158 } 5159 5160 if (!bs->drv->authorizations[BS_FILTER_PASS_DOWN]) { 5161 return false; 5162 } 5163 5164 if (!bs->file) { 5165 return false; 5166 } 5167 5168 return bdrv_recurse_is_first_non_filter(bs->file, candidate); 5169 } 5170 5171 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, 5172 BlockDriverState *candidate) 5173 { 5174 if (bs->drv && bs->drv->bdrv_recurse_is_first_non_filter) { 5175 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); 5176 } 5177 5178 return bdrv_generic_is_first_non_filter(bs, candidate); 5179 } 5180 5181 /* This function checks if the candidate is the first non filter bs down it's 5182 * bs chain. Since we don't have pointers to parents it explore all bs chains 5183 * from the top. Some filters can choose not to pass down the recursion. 5184 */ 5185 bool bdrv_is_first_non_filter(BlockDriverState *candidate) 5186 { 5187 BlockDriverState *bs; 5188 5189 /* walk down the bs forest recursively */ 5190 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 5191 bool perm; 5192 5193 if (!bs->file) { 5194 continue; 5195 } 5196 5197 perm = bdrv_recurse_is_first_non_filter(bs->file, candidate); 5198 5199 /* candidate is the first non filter */ 5200 if (perm) { 5201 return true; 5202 } 5203 } 5204 5205 return false; 5206 } 5207