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