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_preadv(BlockDriverState *bs, 74 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 75 BdrvRequestFlags flags); 76 static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, 77 int64_t offset, unsigned int bytes, 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 unsigned int bytes, 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, is_write, bytes); 209 210 211 /* if the next request must wait -> do nothing */ 212 if (throttle_schedule_timer(&bs->throttle_state, is_write)) { 213 return; 214 } 215 216 /* else queue next request for execution */ 217 qemu_co_queue_next(&bs->throttled_reqs[is_write]); 218 } 219 220 size_t bdrv_opt_mem_align(BlockDriverState *bs) 221 { 222 if (!bs || !bs->drv) { 223 /* 4k should be on the safe side */ 224 return 4096; 225 } 226 227 return bs->bl.opt_mem_alignment; 228 } 229 230 /* check if the path starts with "<protocol>:" */ 231 static int path_has_protocol(const char *path) 232 { 233 const char *p; 234 235 #ifdef _WIN32 236 if (is_windows_drive(path) || 237 is_windows_drive_prefix(path)) { 238 return 0; 239 } 240 p = path + strcspn(path, ":/\\"); 241 #else 242 p = path + strcspn(path, ":/"); 243 #endif 244 245 return *p == ':'; 246 } 247 248 int path_is_absolute(const char *path) 249 { 250 #ifdef _WIN32 251 /* specific case for names like: "\\.\d:" */ 252 if (is_windows_drive(path) || is_windows_drive_prefix(path)) { 253 return 1; 254 } 255 return (*path == '/' || *path == '\\'); 256 #else 257 return (*path == '/'); 258 #endif 259 } 260 261 /* if filename is absolute, just copy it to dest. Otherwise, build a 262 path to it by considering it is relative to base_path. URL are 263 supported. */ 264 void path_combine(char *dest, int dest_size, 265 const char *base_path, 266 const char *filename) 267 { 268 const char *p, *p1; 269 int len; 270 271 if (dest_size <= 0) 272 return; 273 if (path_is_absolute(filename)) { 274 pstrcpy(dest, dest_size, filename); 275 } else { 276 p = strchr(base_path, ':'); 277 if (p) 278 p++; 279 else 280 p = base_path; 281 p1 = strrchr(base_path, '/'); 282 #ifdef _WIN32 283 { 284 const char *p2; 285 p2 = strrchr(base_path, '\\'); 286 if (!p1 || p2 > p1) 287 p1 = p2; 288 } 289 #endif 290 if (p1) 291 p1++; 292 else 293 p1 = base_path; 294 if (p1 > p) 295 p = p1; 296 len = p - base_path; 297 if (len > dest_size - 1) 298 len = dest_size - 1; 299 memcpy(dest, base_path, len); 300 dest[len] = '\0'; 301 pstrcat(dest, dest_size, filename); 302 } 303 } 304 305 void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz) 306 { 307 if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) { 308 pstrcpy(dest, sz, bs->backing_file); 309 } else { 310 path_combine(dest, sz, bs->filename, bs->backing_file); 311 } 312 } 313 314 void bdrv_register(BlockDriver *bdrv) 315 { 316 /* Block drivers without coroutine functions need emulation */ 317 if (!bdrv->bdrv_co_readv) { 318 bdrv->bdrv_co_readv = bdrv_co_readv_em; 319 bdrv->bdrv_co_writev = bdrv_co_writev_em; 320 321 /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if 322 * the block driver lacks aio we need to emulate that too. 323 */ 324 if (!bdrv->bdrv_aio_readv) { 325 /* add AIO emulation layer */ 326 bdrv->bdrv_aio_readv = bdrv_aio_readv_em; 327 bdrv->bdrv_aio_writev = bdrv_aio_writev_em; 328 } 329 } 330 331 QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list); 332 } 333 334 /* create a new block device (by default it is empty) */ 335 BlockDriverState *bdrv_new(const char *device_name) 336 { 337 BlockDriverState *bs; 338 339 bs = g_malloc0(sizeof(BlockDriverState)); 340 QLIST_INIT(&bs->dirty_bitmaps); 341 pstrcpy(bs->device_name, sizeof(bs->device_name), device_name); 342 if (device_name[0] != '\0') { 343 QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list); 344 } 345 bdrv_iostatus_disable(bs); 346 notifier_list_init(&bs->close_notifiers); 347 notifier_with_return_list_init(&bs->before_write_notifiers); 348 qemu_co_queue_init(&bs->throttled_reqs[0]); 349 qemu_co_queue_init(&bs->throttled_reqs[1]); 350 bs->refcnt = 1; 351 352 return bs; 353 } 354 355 void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify) 356 { 357 notifier_list_add(&bs->close_notifiers, notify); 358 } 359 360 BlockDriver *bdrv_find_format(const char *format_name) 361 { 362 BlockDriver *drv1; 363 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 364 if (!strcmp(drv1->format_name, format_name)) { 365 return drv1; 366 } 367 } 368 return NULL; 369 } 370 371 static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only) 372 { 373 static const char *whitelist_rw[] = { 374 CONFIG_BDRV_RW_WHITELIST 375 }; 376 static const char *whitelist_ro[] = { 377 CONFIG_BDRV_RO_WHITELIST 378 }; 379 const char **p; 380 381 if (!whitelist_rw[0] && !whitelist_ro[0]) { 382 return 1; /* no whitelist, anything goes */ 383 } 384 385 for (p = whitelist_rw; *p; p++) { 386 if (!strcmp(drv->format_name, *p)) { 387 return 1; 388 } 389 } 390 if (read_only) { 391 for (p = whitelist_ro; *p; p++) { 392 if (!strcmp(drv->format_name, *p)) { 393 return 1; 394 } 395 } 396 } 397 return 0; 398 } 399 400 BlockDriver *bdrv_find_whitelisted_format(const char *format_name, 401 bool read_only) 402 { 403 BlockDriver *drv = bdrv_find_format(format_name); 404 return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL; 405 } 406 407 typedef struct CreateCo { 408 BlockDriver *drv; 409 char *filename; 410 QEMUOptionParameter *options; 411 int ret; 412 Error *err; 413 } CreateCo; 414 415 static void coroutine_fn bdrv_create_co_entry(void *opaque) 416 { 417 Error *local_err = NULL; 418 int ret; 419 420 CreateCo *cco = opaque; 421 assert(cco->drv); 422 423 ret = cco->drv->bdrv_create(cco->filename, cco->options, &local_err); 424 if (error_is_set(&local_err)) { 425 error_propagate(&cco->err, local_err); 426 } 427 cco->ret = ret; 428 } 429 430 int bdrv_create(BlockDriver *drv, const char* filename, 431 QEMUOptionParameter *options, Error **errp) 432 { 433 int ret; 434 435 Coroutine *co; 436 CreateCo cco = { 437 .drv = drv, 438 .filename = g_strdup(filename), 439 .options = options, 440 .ret = NOT_DONE, 441 .err = NULL, 442 }; 443 444 if (!drv->bdrv_create) { 445 error_setg(errp, "Driver '%s' does not support image creation", drv->format_name); 446 ret = -ENOTSUP; 447 goto out; 448 } 449 450 if (qemu_in_coroutine()) { 451 /* Fast-path if already in coroutine context */ 452 bdrv_create_co_entry(&cco); 453 } else { 454 co = qemu_coroutine_create(bdrv_create_co_entry); 455 qemu_coroutine_enter(co, &cco); 456 while (cco.ret == NOT_DONE) { 457 qemu_aio_wait(); 458 } 459 } 460 461 ret = cco.ret; 462 if (ret < 0) { 463 if (error_is_set(&cco.err)) { 464 error_propagate(errp, cco.err); 465 } else { 466 error_setg_errno(errp, -ret, "Could not create image"); 467 } 468 } 469 470 out: 471 g_free(cco.filename); 472 return ret; 473 } 474 475 int bdrv_create_file(const char* filename, QEMUOptionParameter *options, 476 Error **errp) 477 { 478 BlockDriver *drv; 479 Error *local_err = NULL; 480 int ret; 481 482 drv = bdrv_find_protocol(filename, true); 483 if (drv == NULL) { 484 error_setg(errp, "Could not find protocol for file '%s'", filename); 485 return -ENOENT; 486 } 487 488 ret = bdrv_create(drv, filename, options, &local_err); 489 if (error_is_set(&local_err)) { 490 error_propagate(errp, local_err); 491 } 492 return ret; 493 } 494 495 int bdrv_refresh_limits(BlockDriverState *bs) 496 { 497 BlockDriver *drv = bs->drv; 498 499 memset(&bs->bl, 0, sizeof(bs->bl)); 500 501 if (!drv) { 502 return 0; 503 } 504 505 /* Take some limits from the children as a default */ 506 if (bs->file) { 507 bdrv_refresh_limits(bs->file); 508 bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length; 509 bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment; 510 } else { 511 bs->bl.opt_mem_alignment = 512; 512 } 513 514 if (bs->backing_hd) { 515 bdrv_refresh_limits(bs->backing_hd); 516 bs->bl.opt_transfer_length = 517 MAX(bs->bl.opt_transfer_length, 518 bs->backing_hd->bl.opt_transfer_length); 519 bs->bl.opt_mem_alignment = 520 MAX(bs->bl.opt_mem_alignment, 521 bs->backing_hd->bl.opt_mem_alignment); 522 } 523 524 /* Then let the driver override it */ 525 if (drv->bdrv_refresh_limits) { 526 return drv->bdrv_refresh_limits(bs); 527 } 528 529 return 0; 530 } 531 532 /* 533 * Create a uniquely-named empty temporary file. 534 * Return 0 upon success, otherwise a negative errno value. 535 */ 536 int get_tmp_filename(char *filename, int size) 537 { 538 #ifdef _WIN32 539 char temp_dir[MAX_PATH]; 540 /* GetTempFileName requires that its output buffer (4th param) 541 have length MAX_PATH or greater. */ 542 assert(size >= MAX_PATH); 543 return (GetTempPath(MAX_PATH, temp_dir) 544 && GetTempFileName(temp_dir, "qem", 0, filename) 545 ? 0 : -GetLastError()); 546 #else 547 int fd; 548 const char *tmpdir; 549 tmpdir = getenv("TMPDIR"); 550 if (!tmpdir) 551 tmpdir = "/tmp"; 552 if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) { 553 return -EOVERFLOW; 554 } 555 fd = mkstemp(filename); 556 if (fd < 0) { 557 return -errno; 558 } 559 if (close(fd) != 0) { 560 unlink(filename); 561 return -errno; 562 } 563 return 0; 564 #endif 565 } 566 567 /* 568 * Detect host devices. By convention, /dev/cdrom[N] is always 569 * recognized as a host CDROM. 570 */ 571 static BlockDriver *find_hdev_driver(const char *filename) 572 { 573 int score_max = 0, score; 574 BlockDriver *drv = NULL, *d; 575 576 QLIST_FOREACH(d, &bdrv_drivers, list) { 577 if (d->bdrv_probe_device) { 578 score = d->bdrv_probe_device(filename); 579 if (score > score_max) { 580 score_max = score; 581 drv = d; 582 } 583 } 584 } 585 586 return drv; 587 } 588 589 BlockDriver *bdrv_find_protocol(const char *filename, 590 bool allow_protocol_prefix) 591 { 592 BlockDriver *drv1; 593 char protocol[128]; 594 int len; 595 const char *p; 596 597 /* TODO Drivers without bdrv_file_open must be specified explicitly */ 598 599 /* 600 * XXX(hch): we really should not let host device detection 601 * override an explicit protocol specification, but moving this 602 * later breaks access to device names with colons in them. 603 * Thanks to the brain-dead persistent naming schemes on udev- 604 * based Linux systems those actually are quite common. 605 */ 606 drv1 = find_hdev_driver(filename); 607 if (drv1) { 608 return drv1; 609 } 610 611 if (!path_has_protocol(filename) || !allow_protocol_prefix) { 612 return bdrv_find_format("file"); 613 } 614 615 p = strchr(filename, ':'); 616 assert(p != NULL); 617 len = p - filename; 618 if (len > sizeof(protocol) - 1) 619 len = sizeof(protocol) - 1; 620 memcpy(protocol, filename, len); 621 protocol[len] = '\0'; 622 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 623 if (drv1->protocol_name && 624 !strcmp(drv1->protocol_name, protocol)) { 625 return drv1; 626 } 627 } 628 return NULL; 629 } 630 631 static int find_image_format(BlockDriverState *bs, const char *filename, 632 BlockDriver **pdrv, Error **errp) 633 { 634 int score, score_max; 635 BlockDriver *drv1, *drv; 636 uint8_t buf[2048]; 637 int ret = 0; 638 639 /* Return the raw BlockDriver * to scsi-generic devices or empty drives */ 640 if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) { 641 drv = bdrv_find_format("raw"); 642 if (!drv) { 643 error_setg(errp, "Could not find raw image format"); 644 ret = -ENOENT; 645 } 646 *pdrv = drv; 647 return ret; 648 } 649 650 ret = bdrv_pread(bs, 0, buf, sizeof(buf)); 651 if (ret < 0) { 652 error_setg_errno(errp, -ret, "Could not read image for determining its " 653 "format"); 654 *pdrv = NULL; 655 return ret; 656 } 657 658 score_max = 0; 659 drv = NULL; 660 QLIST_FOREACH(drv1, &bdrv_drivers, list) { 661 if (drv1->bdrv_probe) { 662 score = drv1->bdrv_probe(buf, ret, filename); 663 if (score > score_max) { 664 score_max = score; 665 drv = drv1; 666 } 667 } 668 } 669 if (!drv) { 670 error_setg(errp, "Could not determine image format: No compatible " 671 "driver found"); 672 ret = -ENOENT; 673 } 674 *pdrv = drv; 675 return ret; 676 } 677 678 /** 679 * Set the current 'total_sectors' value 680 */ 681 static int refresh_total_sectors(BlockDriverState *bs, int64_t hint) 682 { 683 BlockDriver *drv = bs->drv; 684 685 /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */ 686 if (bs->sg) 687 return 0; 688 689 /* query actual device if possible, otherwise just trust the hint */ 690 if (drv->bdrv_getlength) { 691 int64_t length = drv->bdrv_getlength(bs); 692 if (length < 0) { 693 return length; 694 } 695 hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE); 696 } 697 698 bs->total_sectors = hint; 699 return 0; 700 } 701 702 /** 703 * Set open flags for a given discard mode 704 * 705 * Return 0 on success, -1 if the discard mode was invalid. 706 */ 707 int bdrv_parse_discard_flags(const char *mode, int *flags) 708 { 709 *flags &= ~BDRV_O_UNMAP; 710 711 if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) { 712 /* do nothing */ 713 } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) { 714 *flags |= BDRV_O_UNMAP; 715 } else { 716 return -1; 717 } 718 719 return 0; 720 } 721 722 /** 723 * Set open flags for a given cache mode 724 * 725 * Return 0 on success, -1 if the cache mode was invalid. 726 */ 727 int bdrv_parse_cache_flags(const char *mode, int *flags) 728 { 729 *flags &= ~BDRV_O_CACHE_MASK; 730 731 if (!strcmp(mode, "off") || !strcmp(mode, "none")) { 732 *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; 733 } else if (!strcmp(mode, "directsync")) { 734 *flags |= BDRV_O_NOCACHE; 735 } else if (!strcmp(mode, "writeback")) { 736 *flags |= BDRV_O_CACHE_WB; 737 } else if (!strcmp(mode, "unsafe")) { 738 *flags |= BDRV_O_CACHE_WB; 739 *flags |= BDRV_O_NO_FLUSH; 740 } else if (!strcmp(mode, "writethrough")) { 741 /* this is the default */ 742 } else { 743 return -1; 744 } 745 746 return 0; 747 } 748 749 /** 750 * The copy-on-read flag is actually a reference count so multiple users may 751 * use the feature without worrying about clobbering its previous state. 752 * Copy-on-read stays enabled until all users have called to disable it. 753 */ 754 void bdrv_enable_copy_on_read(BlockDriverState *bs) 755 { 756 bs->copy_on_read++; 757 } 758 759 void bdrv_disable_copy_on_read(BlockDriverState *bs) 760 { 761 assert(bs->copy_on_read > 0); 762 bs->copy_on_read--; 763 } 764 765 static int bdrv_open_flags(BlockDriverState *bs, int flags) 766 { 767 int open_flags = flags | BDRV_O_CACHE_WB; 768 769 /* 770 * Clear flags that are internal to the block layer before opening the 771 * image. 772 */ 773 open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 774 775 /* 776 * Snapshots should be writable. 777 */ 778 if (bs->is_temporary) { 779 open_flags |= BDRV_O_RDWR; 780 } 781 782 return open_flags; 783 } 784 785 static int bdrv_assign_node_name(BlockDriverState *bs, 786 const char *node_name, 787 Error **errp) 788 { 789 if (!node_name) { 790 return 0; 791 } 792 793 /* empty string node name is invalid */ 794 if (node_name[0] == '\0') { 795 error_setg(errp, "Empty node name"); 796 return -EINVAL; 797 } 798 799 /* takes care of avoiding namespaces collisions */ 800 if (bdrv_find(node_name)) { 801 error_setg(errp, "node-name=%s is conflicting with a device id", 802 node_name); 803 return -EINVAL; 804 } 805 806 /* takes care of avoiding duplicates node names */ 807 if (bdrv_find_node(node_name)) { 808 error_setg(errp, "Duplicate node name"); 809 return -EINVAL; 810 } 811 812 /* copy node name into the bs and insert it into the graph list */ 813 pstrcpy(bs->node_name, sizeof(bs->node_name), node_name); 814 QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list); 815 816 return 0; 817 } 818 819 /* 820 * Common part for opening disk images and files 821 * 822 * Removes all processed options from *options. 823 */ 824 static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file, 825 QDict *options, int flags, BlockDriver *drv, Error **errp) 826 { 827 int ret, open_flags; 828 const char *filename; 829 const char *node_name = NULL; 830 Error *local_err = NULL; 831 832 assert(drv != NULL); 833 assert(bs->file == NULL); 834 assert(options != NULL && bs->options != options); 835 836 if (file != NULL) { 837 filename = file->filename; 838 } else { 839 filename = qdict_get_try_str(options, "filename"); 840 } 841 842 if (drv->bdrv_needs_filename && !filename) { 843 error_setg(errp, "The '%s' block driver requires a file name", 844 drv->format_name); 845 return -EINVAL; 846 } 847 848 trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name); 849 850 node_name = qdict_get_try_str(options, "node-name"); 851 ret = bdrv_assign_node_name(bs, node_name, errp); 852 if (ret < 0) { 853 return ret; 854 } 855 qdict_del(options, "node-name"); 856 857 /* bdrv_open() with directly using a protocol as drv. This layer is already 858 * opened, so assign it to bs (while file becomes a closed BlockDriverState) 859 * and return immediately. */ 860 if (file != NULL && drv->bdrv_file_open) { 861 bdrv_swap(file, bs); 862 return 0; 863 } 864 865 bs->open_flags = flags; 866 bs->guest_block_size = 512; 867 bs->request_alignment = 512; 868 bs->zero_beyond_eof = true; 869 open_flags = bdrv_open_flags(bs, flags); 870 bs->read_only = !(open_flags & BDRV_O_RDWR); 871 872 if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) { 873 error_setg(errp, 874 !bs->read_only && bdrv_is_whitelisted(drv, true) 875 ? "Driver '%s' can only be used for read-only devices" 876 : "Driver '%s' is not whitelisted", 877 drv->format_name); 878 return -ENOTSUP; 879 } 880 881 assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */ 882 if (flags & BDRV_O_COPY_ON_READ) { 883 if (!bs->read_only) { 884 bdrv_enable_copy_on_read(bs); 885 } else { 886 error_setg(errp, "Can't use copy-on-read on read-only device"); 887 return -EINVAL; 888 } 889 } 890 891 if (filename != NULL) { 892 pstrcpy(bs->filename, sizeof(bs->filename), filename); 893 } else { 894 bs->filename[0] = '\0'; 895 } 896 897 bs->drv = drv; 898 bs->opaque = g_malloc0(drv->instance_size); 899 900 bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB); 901 902 /* Open the image, either directly or using a protocol */ 903 if (drv->bdrv_file_open) { 904 assert(file == NULL); 905 assert(!drv->bdrv_needs_filename || filename != NULL); 906 ret = drv->bdrv_file_open(bs, options, open_flags, &local_err); 907 } else { 908 if (file == NULL) { 909 error_setg(errp, "Can't use '%s' as a block driver for the " 910 "protocol level", drv->format_name); 911 ret = -EINVAL; 912 goto free_and_fail; 913 } 914 bs->file = file; 915 ret = drv->bdrv_open(bs, options, open_flags, &local_err); 916 } 917 918 if (ret < 0) { 919 if (error_is_set(&local_err)) { 920 error_propagate(errp, local_err); 921 } else if (bs->filename[0]) { 922 error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename); 923 } else { 924 error_setg_errno(errp, -ret, "Could not open image"); 925 } 926 goto free_and_fail; 927 } 928 929 ret = refresh_total_sectors(bs, bs->total_sectors); 930 if (ret < 0) { 931 error_setg_errno(errp, -ret, "Could not refresh total sector count"); 932 goto free_and_fail; 933 } 934 935 bdrv_refresh_limits(bs); 936 assert(bdrv_opt_mem_align(bs) != 0); 937 assert(bs->request_alignment != 0); 938 939 #ifndef _WIN32 940 if (bs->is_temporary) { 941 assert(bs->filename[0] != '\0'); 942 unlink(bs->filename); 943 } 944 #endif 945 return 0; 946 947 free_and_fail: 948 bs->file = NULL; 949 g_free(bs->opaque); 950 bs->opaque = NULL; 951 bs->drv = NULL; 952 return ret; 953 } 954 955 /* 956 * Opens a file using a protocol (file, host_device, nbd, ...) 957 * 958 * options is a QDict of options to pass to the block drivers, or NULL for an 959 * empty set of options. The reference to the QDict belongs to the block layer 960 * after the call (even on failure), so if the caller intends to reuse the 961 * dictionary, it needs to use QINCREF() before calling bdrv_file_open. 962 */ 963 int bdrv_file_open(BlockDriverState **pbs, const char *filename, 964 const char *reference, QDict *options, int flags, 965 Error **errp) 966 { 967 BlockDriverState *bs = NULL; 968 BlockDriver *drv; 969 const char *drvname; 970 bool allow_protocol_prefix = false; 971 Error *local_err = NULL; 972 int ret; 973 974 /* NULL means an empty set of options */ 975 if (options == NULL) { 976 options = qdict_new(); 977 } 978 979 if (reference) { 980 if (filename || qdict_size(options)) { 981 error_setg(errp, "Cannot reference an existing block device with " 982 "additional options or a new filename"); 983 return -EINVAL; 984 } 985 QDECREF(options); 986 987 bs = bdrv_lookup_bs(reference, reference, errp); 988 if (!bs) { 989 return -ENODEV; 990 } 991 bdrv_ref(bs); 992 *pbs = bs; 993 return 0; 994 } 995 996 bs = bdrv_new(""); 997 bs->options = options; 998 options = qdict_clone_shallow(options); 999 1000 /* Fetch the file name from the options QDict if necessary */ 1001 if (!filename) { 1002 filename = qdict_get_try_str(options, "filename"); 1003 } else if (filename && !qdict_haskey(options, "filename")) { 1004 qdict_put(options, "filename", qstring_from_str(filename)); 1005 allow_protocol_prefix = true; 1006 } else { 1007 error_setg(errp, "Can't specify 'file' and 'filename' options at the " 1008 "same time"); 1009 ret = -EINVAL; 1010 goto fail; 1011 } 1012 1013 /* Find the right block driver */ 1014 drvname = qdict_get_try_str(options, "driver"); 1015 if (drvname) { 1016 drv = bdrv_find_format(drvname); 1017 if (!drv) { 1018 error_setg(errp, "Unknown driver '%s'", drvname); 1019 } 1020 qdict_del(options, "driver"); 1021 } else if (filename) { 1022 drv = bdrv_find_protocol(filename, allow_protocol_prefix); 1023 if (!drv) { 1024 error_setg(errp, "Unknown protocol"); 1025 } 1026 } else { 1027 error_setg(errp, "Must specify either driver or file"); 1028 drv = NULL; 1029 } 1030 1031 if (!drv) { 1032 /* errp has been set already */ 1033 ret = -ENOENT; 1034 goto fail; 1035 } 1036 1037 /* Parse the filename and open it */ 1038 if (drv->bdrv_parse_filename && filename) { 1039 drv->bdrv_parse_filename(filename, options, &local_err); 1040 if (error_is_set(&local_err)) { 1041 error_propagate(errp, local_err); 1042 ret = -EINVAL; 1043 goto fail; 1044 } 1045 qdict_del(options, "filename"); 1046 } 1047 1048 if (!drv->bdrv_file_open) { 1049 ret = bdrv_open(bs, filename, options, flags, drv, &local_err); 1050 options = NULL; 1051 } else { 1052 ret = bdrv_open_common(bs, NULL, options, flags, drv, &local_err); 1053 } 1054 if (ret < 0) { 1055 error_propagate(errp, local_err); 1056 goto fail; 1057 } 1058 1059 /* Check if any unknown options were used */ 1060 if (options && (qdict_size(options) != 0)) { 1061 const QDictEntry *entry = qdict_first(options); 1062 error_setg(errp, "Block protocol '%s' doesn't support the option '%s'", 1063 drv->format_name, entry->key); 1064 ret = -EINVAL; 1065 goto fail; 1066 } 1067 QDECREF(options); 1068 1069 bs->growable = 1; 1070 *pbs = bs; 1071 return 0; 1072 1073 fail: 1074 QDECREF(options); 1075 if (!bs->drv) { 1076 QDECREF(bs->options); 1077 } 1078 bdrv_unref(bs); 1079 return ret; 1080 } 1081 1082 /* 1083 * Opens the backing file for a BlockDriverState if not yet open 1084 * 1085 * options is a QDict of options to pass to the block drivers, or NULL for an 1086 * empty set of options. The reference to the QDict is transferred to this 1087 * function (even on failure), so if the caller intends to reuse the dictionary, 1088 * it needs to use QINCREF() before calling bdrv_file_open. 1089 */ 1090 int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) 1091 { 1092 char backing_filename[PATH_MAX]; 1093 int back_flags, ret; 1094 BlockDriver *back_drv = NULL; 1095 Error *local_err = NULL; 1096 1097 if (bs->backing_hd != NULL) { 1098 QDECREF(options); 1099 return 0; 1100 } 1101 1102 /* NULL means an empty set of options */ 1103 if (options == NULL) { 1104 options = qdict_new(); 1105 } 1106 1107 bs->open_flags &= ~BDRV_O_NO_BACKING; 1108 if (qdict_haskey(options, "file.filename")) { 1109 backing_filename[0] = '\0'; 1110 } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { 1111 QDECREF(options); 1112 return 0; 1113 } else { 1114 bdrv_get_full_backing_filename(bs, backing_filename, 1115 sizeof(backing_filename)); 1116 } 1117 1118 bs->backing_hd = bdrv_new(""); 1119 1120 if (bs->backing_format[0] != '\0') { 1121 back_drv = bdrv_find_format(bs->backing_format); 1122 } 1123 1124 /* backing files always opened read-only */ 1125 back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | 1126 BDRV_O_COPY_ON_READ); 1127 1128 ret = bdrv_open(bs->backing_hd, 1129 *backing_filename ? backing_filename : NULL, options, 1130 back_flags, back_drv, &local_err); 1131 if (ret < 0) { 1132 bdrv_unref(bs->backing_hd); 1133 bs->backing_hd = NULL; 1134 bs->open_flags |= BDRV_O_NO_BACKING; 1135 error_setg(errp, "Could not open backing file: %s", 1136 error_get_pretty(local_err)); 1137 error_free(local_err); 1138 return ret; 1139 } 1140 1141 if (bs->backing_hd->file) { 1142 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 1143 bs->backing_hd->file->filename); 1144 } 1145 1146 /* Recalculate the BlockLimits with the backing file */ 1147 bdrv_refresh_limits(bs); 1148 1149 return 0; 1150 } 1151 1152 /* 1153 * Opens a disk image whose options are given as BlockdevRef in another block 1154 * device's options. 1155 * 1156 * If force_raw is true, bdrv_file_open() will be used, thereby preventing any 1157 * image format auto-detection. If it is false and a filename is given, 1158 * bdrv_open() will be used for auto-detection. 1159 * 1160 * If allow_none is true, no image will be opened if filename is false and no 1161 * BlockdevRef is given. *pbs will remain unchanged and 0 will be returned. 1162 * 1163 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict. 1164 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict 1165 * itself, all options starting with "${bdref_key}." are considered part of the 1166 * BlockdevRef. 1167 * 1168 * The BlockdevRef will be removed from the options QDict. 1169 */ 1170 int bdrv_open_image(BlockDriverState **pbs, const char *filename, 1171 QDict *options, const char *bdref_key, int flags, 1172 bool force_raw, bool allow_none, Error **errp) 1173 { 1174 QDict *image_options; 1175 int ret; 1176 char *bdref_key_dot; 1177 const char *reference; 1178 1179 bdref_key_dot = g_strdup_printf("%s.", bdref_key); 1180 qdict_extract_subqdict(options, &image_options, bdref_key_dot); 1181 g_free(bdref_key_dot); 1182 1183 reference = qdict_get_try_str(options, bdref_key); 1184 if (!filename && !reference && !qdict_size(image_options)) { 1185 if (allow_none) { 1186 ret = 0; 1187 } else { 1188 error_setg(errp, "A block device must be specified for \"%s\"", 1189 bdref_key); 1190 ret = -EINVAL; 1191 } 1192 goto done; 1193 } 1194 1195 if (filename && !force_raw) { 1196 /* If a filename is given and the block driver should be detected 1197 automatically (instead of using none), use bdrv_open() in order to do 1198 that auto-detection. */ 1199 BlockDriverState *bs; 1200 1201 if (reference) { 1202 error_setg(errp, "Cannot reference an existing block device while " 1203 "giving a filename"); 1204 ret = -EINVAL; 1205 goto done; 1206 } 1207 1208 bs = bdrv_new(""); 1209 ret = bdrv_open(bs, filename, image_options, flags, NULL, errp); 1210 if (ret < 0) { 1211 bdrv_unref(bs); 1212 } else { 1213 *pbs = bs; 1214 } 1215 } else { 1216 ret = bdrv_file_open(pbs, filename, reference, image_options, flags, 1217 errp); 1218 } 1219 1220 done: 1221 qdict_del(options, bdref_key); 1222 return ret; 1223 } 1224 1225 /* 1226 * Opens a disk image (raw, qcow2, vmdk, ...) 1227 * 1228 * options is a QDict of options to pass to the block drivers, or NULL for an 1229 * empty set of options. The reference to the QDict belongs to the block layer 1230 * after the call (even on failure), so if the caller intends to reuse the 1231 * dictionary, it needs to use QINCREF() before calling bdrv_open. 1232 */ 1233 int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options, 1234 int flags, BlockDriver *drv, Error **errp) 1235 { 1236 int ret; 1237 /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */ 1238 char tmp_filename[PATH_MAX + 1]; 1239 BlockDriverState *file = NULL; 1240 const char *drvname; 1241 Error *local_err = NULL; 1242 1243 /* NULL means an empty set of options */ 1244 if (options == NULL) { 1245 options = qdict_new(); 1246 } 1247 1248 bs->options = options; 1249 options = qdict_clone_shallow(options); 1250 1251 /* For snapshot=on, create a temporary qcow2 overlay */ 1252 if (flags & BDRV_O_SNAPSHOT) { 1253 BlockDriverState *bs1; 1254 int64_t total_size; 1255 BlockDriver *bdrv_qcow2; 1256 QEMUOptionParameter *create_options; 1257 QDict *snapshot_options; 1258 1259 /* if snapshot, we create a temporary backing file and open it 1260 instead of opening 'filename' directly */ 1261 1262 /* Get the required size from the image */ 1263 bs1 = bdrv_new(""); 1264 QINCREF(options); 1265 ret = bdrv_open(bs1, filename, options, BDRV_O_NO_BACKING, 1266 drv, &local_err); 1267 if (ret < 0) { 1268 bdrv_unref(bs1); 1269 goto fail; 1270 } 1271 total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK; 1272 1273 bdrv_unref(bs1); 1274 1275 /* Create the temporary image */ 1276 ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename)); 1277 if (ret < 0) { 1278 error_setg_errno(errp, -ret, "Could not get temporary filename"); 1279 goto fail; 1280 } 1281 1282 bdrv_qcow2 = bdrv_find_format("qcow2"); 1283 create_options = parse_option_parameters("", bdrv_qcow2->create_options, 1284 NULL); 1285 1286 set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size); 1287 1288 ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err); 1289 free_option_parameters(create_options); 1290 if (ret < 0) { 1291 error_setg_errno(errp, -ret, "Could not create temporary overlay " 1292 "'%s': %s", tmp_filename, 1293 error_get_pretty(local_err)); 1294 error_free(local_err); 1295 local_err = NULL; 1296 goto fail; 1297 } 1298 1299 /* Prepare a new options QDict for the temporary file, where user 1300 * options refer to the backing file */ 1301 if (filename) { 1302 qdict_put(options, "file.filename", qstring_from_str(filename)); 1303 } 1304 if (drv) { 1305 qdict_put(options, "driver", qstring_from_str(drv->format_name)); 1306 } 1307 1308 snapshot_options = qdict_new(); 1309 qdict_put(snapshot_options, "backing", options); 1310 qdict_flatten(snapshot_options); 1311 1312 bs->options = snapshot_options; 1313 options = qdict_clone_shallow(bs->options); 1314 1315 filename = tmp_filename; 1316 drv = bdrv_qcow2; 1317 bs->is_temporary = 1; 1318 } 1319 1320 /* Open image file without format layer */ 1321 if (flags & BDRV_O_RDWR) { 1322 flags |= BDRV_O_ALLOW_RDWR; 1323 } 1324 1325 ret = bdrv_open_image(&file, filename, options, "file", 1326 bdrv_open_flags(bs, flags | BDRV_O_UNMAP), true, true, 1327 &local_err); 1328 if (ret < 0) { 1329 goto fail; 1330 } 1331 1332 /* Find the right image format driver */ 1333 drvname = qdict_get_try_str(options, "driver"); 1334 if (drvname) { 1335 drv = bdrv_find_format(drvname); 1336 qdict_del(options, "driver"); 1337 if (!drv) { 1338 error_setg(errp, "Invalid driver: '%s'", drvname); 1339 ret = -EINVAL; 1340 goto unlink_and_fail; 1341 } 1342 } 1343 1344 if (!drv) { 1345 if (file) { 1346 ret = find_image_format(file, filename, &drv, &local_err); 1347 } else { 1348 error_setg(errp, "Must specify either driver or file"); 1349 ret = -EINVAL; 1350 goto unlink_and_fail; 1351 } 1352 } 1353 1354 if (!drv) { 1355 goto unlink_and_fail; 1356 } 1357 1358 /* Open the image */ 1359 ret = bdrv_open_common(bs, file, options, flags, drv, &local_err); 1360 if (ret < 0) { 1361 goto unlink_and_fail; 1362 } 1363 1364 if (file && (bs->file != file)) { 1365 bdrv_unref(file); 1366 file = NULL; 1367 } 1368 1369 /* If there is a backing file, use it */ 1370 if ((flags & BDRV_O_NO_BACKING) == 0) { 1371 QDict *backing_options; 1372 1373 qdict_extract_subqdict(options, &backing_options, "backing."); 1374 ret = bdrv_open_backing_file(bs, backing_options, &local_err); 1375 if (ret < 0) { 1376 goto close_and_fail; 1377 } 1378 } 1379 1380 /* Check if any unknown options were used */ 1381 if (qdict_size(options) != 0) { 1382 const QDictEntry *entry = qdict_first(options); 1383 error_setg(errp, "Block format '%s' used by device '%s' doesn't " 1384 "support the option '%s'", drv->format_name, bs->device_name, 1385 entry->key); 1386 1387 ret = -EINVAL; 1388 goto close_and_fail; 1389 } 1390 QDECREF(options); 1391 1392 if (!bdrv_key_required(bs)) { 1393 bdrv_dev_change_media_cb(bs, true); 1394 } 1395 1396 return 0; 1397 1398 unlink_and_fail: 1399 if (file != NULL) { 1400 bdrv_unref(file); 1401 } 1402 if (bs->is_temporary) { 1403 unlink(filename); 1404 } 1405 fail: 1406 QDECREF(bs->options); 1407 QDECREF(options); 1408 bs->options = NULL; 1409 if (error_is_set(&local_err)) { 1410 error_propagate(errp, local_err); 1411 } 1412 return ret; 1413 1414 close_and_fail: 1415 bdrv_close(bs); 1416 QDECREF(options); 1417 if (error_is_set(&local_err)) { 1418 error_propagate(errp, local_err); 1419 } 1420 return ret; 1421 } 1422 1423 typedef struct BlockReopenQueueEntry { 1424 bool prepared; 1425 BDRVReopenState state; 1426 QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry; 1427 } BlockReopenQueueEntry; 1428 1429 /* 1430 * Adds a BlockDriverState to a simple queue for an atomic, transactional 1431 * reopen of multiple devices. 1432 * 1433 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT 1434 * already performed, or alternatively may be NULL a new BlockReopenQueue will 1435 * be created and initialized. This newly created BlockReopenQueue should be 1436 * passed back in for subsequent calls that are intended to be of the same 1437 * atomic 'set'. 1438 * 1439 * bs is the BlockDriverState to add to the reopen queue. 1440 * 1441 * flags contains the open flags for the associated bs 1442 * 1443 * returns a pointer to bs_queue, which is either the newly allocated 1444 * bs_queue, or the existing bs_queue being used. 1445 * 1446 */ 1447 BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue, 1448 BlockDriverState *bs, int flags) 1449 { 1450 assert(bs != NULL); 1451 1452 BlockReopenQueueEntry *bs_entry; 1453 if (bs_queue == NULL) { 1454 bs_queue = g_new0(BlockReopenQueue, 1); 1455 QSIMPLEQ_INIT(bs_queue); 1456 } 1457 1458 if (bs->file) { 1459 bdrv_reopen_queue(bs_queue, bs->file, flags); 1460 } 1461 1462 bs_entry = g_new0(BlockReopenQueueEntry, 1); 1463 QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry); 1464 1465 bs_entry->state.bs = bs; 1466 bs_entry->state.flags = flags; 1467 1468 return bs_queue; 1469 } 1470 1471 /* 1472 * Reopen multiple BlockDriverStates atomically & transactionally. 1473 * 1474 * The queue passed in (bs_queue) must have been built up previous 1475 * via bdrv_reopen_queue(). 1476 * 1477 * Reopens all BDS specified in the queue, with the appropriate 1478 * flags. All devices are prepared for reopen, and failure of any 1479 * device will cause all device changes to be abandonded, and intermediate 1480 * data cleaned up. 1481 * 1482 * If all devices prepare successfully, then the changes are committed 1483 * to all devices. 1484 * 1485 */ 1486 int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) 1487 { 1488 int ret = -1; 1489 BlockReopenQueueEntry *bs_entry, *next; 1490 Error *local_err = NULL; 1491 1492 assert(bs_queue != NULL); 1493 1494 bdrv_drain_all(); 1495 1496 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 1497 if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) { 1498 error_propagate(errp, local_err); 1499 goto cleanup; 1500 } 1501 bs_entry->prepared = true; 1502 } 1503 1504 /* If we reach this point, we have success and just need to apply the 1505 * changes 1506 */ 1507 QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) { 1508 bdrv_reopen_commit(&bs_entry->state); 1509 } 1510 1511 ret = 0; 1512 1513 cleanup: 1514 QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) { 1515 if (ret && bs_entry->prepared) { 1516 bdrv_reopen_abort(&bs_entry->state); 1517 } 1518 g_free(bs_entry); 1519 } 1520 g_free(bs_queue); 1521 return ret; 1522 } 1523 1524 1525 /* Reopen a single BlockDriverState with the specified flags. */ 1526 int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp) 1527 { 1528 int ret = -1; 1529 Error *local_err = NULL; 1530 BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, bdrv_flags); 1531 1532 ret = bdrv_reopen_multiple(queue, &local_err); 1533 if (local_err != NULL) { 1534 error_propagate(errp, local_err); 1535 } 1536 return ret; 1537 } 1538 1539 1540 /* 1541 * Prepares a BlockDriverState for reopen. All changes are staged in the 1542 * 'opaque' field of the BDRVReopenState, which is used and allocated by 1543 * the block driver layer .bdrv_reopen_prepare() 1544 * 1545 * bs is the BlockDriverState to reopen 1546 * flags are the new open flags 1547 * queue is the reopen queue 1548 * 1549 * Returns 0 on success, non-zero on error. On error errp will be set 1550 * as well. 1551 * 1552 * On failure, bdrv_reopen_abort() will be called to clean up any data. 1553 * It is the responsibility of the caller to then call the abort() or 1554 * commit() for any other BDS that have been left in a prepare() state 1555 * 1556 */ 1557 int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, 1558 Error **errp) 1559 { 1560 int ret = -1; 1561 Error *local_err = NULL; 1562 BlockDriver *drv; 1563 1564 assert(reopen_state != NULL); 1565 assert(reopen_state->bs->drv != NULL); 1566 drv = reopen_state->bs->drv; 1567 1568 /* if we are to stay read-only, do not allow permission change 1569 * to r/w */ 1570 if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) && 1571 reopen_state->flags & BDRV_O_RDWR) { 1572 error_set(errp, QERR_DEVICE_IS_READ_ONLY, 1573 reopen_state->bs->device_name); 1574 goto error; 1575 } 1576 1577 1578 ret = bdrv_flush(reopen_state->bs); 1579 if (ret) { 1580 error_set(errp, ERROR_CLASS_GENERIC_ERROR, "Error (%s) flushing drive", 1581 strerror(-ret)); 1582 goto error; 1583 } 1584 1585 if (drv->bdrv_reopen_prepare) { 1586 ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err); 1587 if (ret) { 1588 if (local_err != NULL) { 1589 error_propagate(errp, local_err); 1590 } else { 1591 error_setg(errp, "failed while preparing to reopen image '%s'", 1592 reopen_state->bs->filename); 1593 } 1594 goto error; 1595 } 1596 } else { 1597 /* It is currently mandatory to have a bdrv_reopen_prepare() 1598 * handler for each supported drv. */ 1599 error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 1600 drv->format_name, reopen_state->bs->device_name, 1601 "reopening of file"); 1602 ret = -1; 1603 goto error; 1604 } 1605 1606 ret = 0; 1607 1608 error: 1609 return ret; 1610 } 1611 1612 /* 1613 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and 1614 * makes them final by swapping the staging BlockDriverState contents into 1615 * the active BlockDriverState contents. 1616 */ 1617 void bdrv_reopen_commit(BDRVReopenState *reopen_state) 1618 { 1619 BlockDriver *drv; 1620 1621 assert(reopen_state != NULL); 1622 drv = reopen_state->bs->drv; 1623 assert(drv != NULL); 1624 1625 /* If there are any driver level actions to take */ 1626 if (drv->bdrv_reopen_commit) { 1627 drv->bdrv_reopen_commit(reopen_state); 1628 } 1629 1630 /* set BDS specific flags now */ 1631 reopen_state->bs->open_flags = reopen_state->flags; 1632 reopen_state->bs->enable_write_cache = !!(reopen_state->flags & 1633 BDRV_O_CACHE_WB); 1634 reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR); 1635 1636 bdrv_refresh_limits(reopen_state->bs); 1637 } 1638 1639 /* 1640 * Abort the reopen, and delete and free the staged changes in 1641 * reopen_state 1642 */ 1643 void bdrv_reopen_abort(BDRVReopenState *reopen_state) 1644 { 1645 BlockDriver *drv; 1646 1647 assert(reopen_state != NULL); 1648 drv = reopen_state->bs->drv; 1649 assert(drv != NULL); 1650 1651 if (drv->bdrv_reopen_abort) { 1652 drv->bdrv_reopen_abort(reopen_state); 1653 } 1654 } 1655 1656 1657 void bdrv_close(BlockDriverState *bs) 1658 { 1659 if (bs->job) { 1660 block_job_cancel_sync(bs->job); 1661 } 1662 bdrv_drain_all(); /* complete I/O */ 1663 bdrv_flush(bs); 1664 bdrv_drain_all(); /* in case flush left pending I/O */ 1665 notifier_list_notify(&bs->close_notifiers, bs); 1666 1667 if (bs->drv) { 1668 if (bs->backing_hd) { 1669 bdrv_unref(bs->backing_hd); 1670 bs->backing_hd = NULL; 1671 } 1672 bs->drv->bdrv_close(bs); 1673 g_free(bs->opaque); 1674 #ifdef _WIN32 1675 if (bs->is_temporary) { 1676 unlink(bs->filename); 1677 } 1678 #endif 1679 bs->opaque = NULL; 1680 bs->drv = NULL; 1681 bs->copy_on_read = 0; 1682 bs->backing_file[0] = '\0'; 1683 bs->backing_format[0] = '\0'; 1684 bs->total_sectors = 0; 1685 bs->encrypted = 0; 1686 bs->valid_key = 0; 1687 bs->sg = 0; 1688 bs->growable = 0; 1689 bs->zero_beyond_eof = false; 1690 QDECREF(bs->options); 1691 bs->options = NULL; 1692 1693 if (bs->file != NULL) { 1694 bdrv_unref(bs->file); 1695 bs->file = NULL; 1696 } 1697 } 1698 1699 bdrv_dev_change_media_cb(bs, false); 1700 1701 /*throttling disk I/O limits*/ 1702 if (bs->io_limits_enabled) { 1703 bdrv_io_limits_disable(bs); 1704 } 1705 } 1706 1707 void bdrv_close_all(void) 1708 { 1709 BlockDriverState *bs; 1710 1711 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 1712 bdrv_close(bs); 1713 } 1714 } 1715 1716 /* Check if any requests are in-flight (including throttled requests) */ 1717 static bool bdrv_requests_pending(BlockDriverState *bs) 1718 { 1719 if (!QLIST_EMPTY(&bs->tracked_requests)) { 1720 return true; 1721 } 1722 if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) { 1723 return true; 1724 } 1725 if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) { 1726 return true; 1727 } 1728 if (bs->file && bdrv_requests_pending(bs->file)) { 1729 return true; 1730 } 1731 if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) { 1732 return true; 1733 } 1734 return false; 1735 } 1736 1737 static bool bdrv_requests_pending_all(void) 1738 { 1739 BlockDriverState *bs; 1740 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 1741 if (bdrv_requests_pending(bs)) { 1742 return true; 1743 } 1744 } 1745 return false; 1746 } 1747 1748 /* 1749 * Wait for pending requests to complete across all BlockDriverStates 1750 * 1751 * This function does not flush data to disk, use bdrv_flush_all() for that 1752 * after calling this function. 1753 * 1754 * Note that completion of an asynchronous I/O operation can trigger any 1755 * number of other I/O operations on other devices---for example a coroutine 1756 * can be arbitrarily complex and a constant flow of I/O can come until the 1757 * coroutine is complete. Because of this, it is not possible to have a 1758 * function to drain a single device's I/O queue. 1759 */ 1760 void bdrv_drain_all(void) 1761 { 1762 /* Always run first iteration so any pending completion BHs run */ 1763 bool busy = true; 1764 BlockDriverState *bs; 1765 1766 while (busy) { 1767 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 1768 bdrv_start_throttled_reqs(bs); 1769 } 1770 1771 busy = bdrv_requests_pending_all(); 1772 busy |= aio_poll(qemu_get_aio_context(), busy); 1773 } 1774 } 1775 1776 /* make a BlockDriverState anonymous by removing from bdrv_state and 1777 * graph_bdrv_state list. 1778 Also, NULL terminate the device_name to prevent double remove */ 1779 void bdrv_make_anon(BlockDriverState *bs) 1780 { 1781 if (bs->device_name[0] != '\0') { 1782 QTAILQ_REMOVE(&bdrv_states, bs, device_list); 1783 } 1784 bs->device_name[0] = '\0'; 1785 if (bs->node_name[0] != '\0') { 1786 QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list); 1787 } 1788 bs->node_name[0] = '\0'; 1789 } 1790 1791 static void bdrv_rebind(BlockDriverState *bs) 1792 { 1793 if (bs->drv && bs->drv->bdrv_rebind) { 1794 bs->drv->bdrv_rebind(bs); 1795 } 1796 } 1797 1798 static void bdrv_move_feature_fields(BlockDriverState *bs_dest, 1799 BlockDriverState *bs_src) 1800 { 1801 /* move some fields that need to stay attached to the device */ 1802 bs_dest->open_flags = bs_src->open_flags; 1803 1804 /* dev info */ 1805 bs_dest->dev_ops = bs_src->dev_ops; 1806 bs_dest->dev_opaque = bs_src->dev_opaque; 1807 bs_dest->dev = bs_src->dev; 1808 bs_dest->guest_block_size = bs_src->guest_block_size; 1809 bs_dest->copy_on_read = bs_src->copy_on_read; 1810 1811 bs_dest->enable_write_cache = bs_src->enable_write_cache; 1812 1813 /* i/o throttled req */ 1814 memcpy(&bs_dest->throttle_state, 1815 &bs_src->throttle_state, 1816 sizeof(ThrottleState)); 1817 bs_dest->throttled_reqs[0] = bs_src->throttled_reqs[0]; 1818 bs_dest->throttled_reqs[1] = bs_src->throttled_reqs[1]; 1819 bs_dest->io_limits_enabled = bs_src->io_limits_enabled; 1820 1821 /* r/w error */ 1822 bs_dest->on_read_error = bs_src->on_read_error; 1823 bs_dest->on_write_error = bs_src->on_write_error; 1824 1825 /* i/o status */ 1826 bs_dest->iostatus_enabled = bs_src->iostatus_enabled; 1827 bs_dest->iostatus = bs_src->iostatus; 1828 1829 /* dirty bitmap */ 1830 bs_dest->dirty_bitmaps = bs_src->dirty_bitmaps; 1831 1832 /* reference count */ 1833 bs_dest->refcnt = bs_src->refcnt; 1834 1835 /* job */ 1836 bs_dest->in_use = bs_src->in_use; 1837 bs_dest->job = bs_src->job; 1838 1839 /* keep the same entry in bdrv_states */ 1840 pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name), 1841 bs_src->device_name); 1842 bs_dest->device_list = bs_src->device_list; 1843 1844 /* keep the same entry in graph_bdrv_states 1845 * We do want to swap name but don't want to swap linked list entries 1846 */ 1847 bs_dest->node_list = bs_src->node_list; 1848 } 1849 1850 /* 1851 * Swap bs contents for two image chains while they are live, 1852 * while keeping required fields on the BlockDriverState that is 1853 * actually attached to a device. 1854 * 1855 * This will modify the BlockDriverState fields, and swap contents 1856 * between bs_new and bs_old. Both bs_new and bs_old are modified. 1857 * 1858 * bs_new is required to be anonymous. 1859 * 1860 * This function does not create any image files. 1861 */ 1862 void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old) 1863 { 1864 BlockDriverState tmp; 1865 1866 /* bs_new must be anonymous and shouldn't have anything fancy enabled */ 1867 assert(bs_new->device_name[0] == '\0'); 1868 assert(QLIST_EMPTY(&bs_new->dirty_bitmaps)); 1869 assert(bs_new->job == NULL); 1870 assert(bs_new->dev == NULL); 1871 assert(bs_new->in_use == 0); 1872 assert(bs_new->io_limits_enabled == false); 1873 assert(!throttle_have_timer(&bs_new->throttle_state)); 1874 1875 tmp = *bs_new; 1876 *bs_new = *bs_old; 1877 *bs_old = tmp; 1878 1879 /* there are some fields that should not be swapped, move them back */ 1880 bdrv_move_feature_fields(&tmp, bs_old); 1881 bdrv_move_feature_fields(bs_old, bs_new); 1882 bdrv_move_feature_fields(bs_new, &tmp); 1883 1884 /* bs_new shouldn't be in bdrv_states even after the swap! */ 1885 assert(bs_new->device_name[0] == '\0'); 1886 1887 /* Check a few fields that should remain attached to the device */ 1888 assert(bs_new->dev == NULL); 1889 assert(bs_new->job == NULL); 1890 assert(bs_new->in_use == 0); 1891 assert(bs_new->io_limits_enabled == false); 1892 assert(!throttle_have_timer(&bs_new->throttle_state)); 1893 1894 bdrv_rebind(bs_new); 1895 bdrv_rebind(bs_old); 1896 } 1897 1898 /* 1899 * Add new bs contents at the top of an image chain while the chain is 1900 * live, while keeping required fields on the top layer. 1901 * 1902 * This will modify the BlockDriverState fields, and swap contents 1903 * between bs_new and bs_top. Both bs_new and bs_top are modified. 1904 * 1905 * bs_new is required to be anonymous. 1906 * 1907 * This function does not create any image files. 1908 */ 1909 void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) 1910 { 1911 bdrv_swap(bs_new, bs_top); 1912 1913 /* The contents of 'tmp' will become bs_top, as we are 1914 * swapping bs_new and bs_top contents. */ 1915 bs_top->backing_hd = bs_new; 1916 bs_top->open_flags &= ~BDRV_O_NO_BACKING; 1917 pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file), 1918 bs_new->filename); 1919 pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format), 1920 bs_new->drv ? bs_new->drv->format_name : ""); 1921 } 1922 1923 static void bdrv_delete(BlockDriverState *bs) 1924 { 1925 assert(!bs->dev); 1926 assert(!bs->job); 1927 assert(!bs->in_use); 1928 assert(!bs->refcnt); 1929 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 1930 1931 bdrv_close(bs); 1932 1933 /* remove from list, if necessary */ 1934 bdrv_make_anon(bs); 1935 1936 g_free(bs); 1937 } 1938 1939 int bdrv_attach_dev(BlockDriverState *bs, void *dev) 1940 /* TODO change to DeviceState *dev when all users are qdevified */ 1941 { 1942 if (bs->dev) { 1943 return -EBUSY; 1944 } 1945 bs->dev = dev; 1946 bdrv_iostatus_reset(bs); 1947 return 0; 1948 } 1949 1950 /* TODO qdevified devices don't use this, remove when devices are qdevified */ 1951 void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev) 1952 { 1953 if (bdrv_attach_dev(bs, dev) < 0) { 1954 abort(); 1955 } 1956 } 1957 1958 void bdrv_detach_dev(BlockDriverState *bs, void *dev) 1959 /* TODO change to DeviceState *dev when all users are qdevified */ 1960 { 1961 assert(bs->dev == dev); 1962 bs->dev = NULL; 1963 bs->dev_ops = NULL; 1964 bs->dev_opaque = NULL; 1965 bs->guest_block_size = 512; 1966 } 1967 1968 /* TODO change to return DeviceState * when all users are qdevified */ 1969 void *bdrv_get_attached_dev(BlockDriverState *bs) 1970 { 1971 return bs->dev; 1972 } 1973 1974 void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops, 1975 void *opaque) 1976 { 1977 bs->dev_ops = ops; 1978 bs->dev_opaque = opaque; 1979 } 1980 1981 void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv, 1982 enum MonitorEvent ev, 1983 BlockErrorAction action, bool is_read) 1984 { 1985 QObject *data; 1986 const char *action_str; 1987 1988 switch (action) { 1989 case BDRV_ACTION_REPORT: 1990 action_str = "report"; 1991 break; 1992 case BDRV_ACTION_IGNORE: 1993 action_str = "ignore"; 1994 break; 1995 case BDRV_ACTION_STOP: 1996 action_str = "stop"; 1997 break; 1998 default: 1999 abort(); 2000 } 2001 2002 data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }", 2003 bdrv->device_name, 2004 action_str, 2005 is_read ? "read" : "write"); 2006 monitor_protocol_event(ev, data); 2007 2008 qobject_decref(data); 2009 } 2010 2011 static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected) 2012 { 2013 QObject *data; 2014 2015 data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }", 2016 bdrv_get_device_name(bs), ejected); 2017 monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data); 2018 2019 qobject_decref(data); 2020 } 2021 2022 static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load) 2023 { 2024 if (bs->dev_ops && bs->dev_ops->change_media_cb) { 2025 bool tray_was_closed = !bdrv_dev_is_tray_open(bs); 2026 bs->dev_ops->change_media_cb(bs->dev_opaque, load); 2027 if (tray_was_closed) { 2028 /* tray open */ 2029 bdrv_emit_qmp_eject_event(bs, true); 2030 } 2031 if (load) { 2032 /* tray close */ 2033 bdrv_emit_qmp_eject_event(bs, false); 2034 } 2035 } 2036 } 2037 2038 bool bdrv_dev_has_removable_media(BlockDriverState *bs) 2039 { 2040 return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb); 2041 } 2042 2043 void bdrv_dev_eject_request(BlockDriverState *bs, bool force) 2044 { 2045 if (bs->dev_ops && bs->dev_ops->eject_request_cb) { 2046 bs->dev_ops->eject_request_cb(bs->dev_opaque, force); 2047 } 2048 } 2049 2050 bool bdrv_dev_is_tray_open(BlockDriverState *bs) 2051 { 2052 if (bs->dev_ops && bs->dev_ops->is_tray_open) { 2053 return bs->dev_ops->is_tray_open(bs->dev_opaque); 2054 } 2055 return false; 2056 } 2057 2058 static void bdrv_dev_resize_cb(BlockDriverState *bs) 2059 { 2060 if (bs->dev_ops && bs->dev_ops->resize_cb) { 2061 bs->dev_ops->resize_cb(bs->dev_opaque); 2062 } 2063 } 2064 2065 bool bdrv_dev_is_medium_locked(BlockDriverState *bs) 2066 { 2067 if (bs->dev_ops && bs->dev_ops->is_medium_locked) { 2068 return bs->dev_ops->is_medium_locked(bs->dev_opaque); 2069 } 2070 return false; 2071 } 2072 2073 /* 2074 * Run consistency checks on an image 2075 * 2076 * Returns 0 if the check could be completed (it doesn't mean that the image is 2077 * free of errors) or -errno when an internal error occurred. The results of the 2078 * check are stored in res. 2079 */ 2080 int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix) 2081 { 2082 if (bs->drv->bdrv_check == NULL) { 2083 return -ENOTSUP; 2084 } 2085 2086 memset(res, 0, sizeof(*res)); 2087 return bs->drv->bdrv_check(bs, res, fix); 2088 } 2089 2090 #define COMMIT_BUF_SECTORS 2048 2091 2092 /* commit COW file into the raw image */ 2093 int bdrv_commit(BlockDriverState *bs) 2094 { 2095 BlockDriver *drv = bs->drv; 2096 int64_t sector, total_sectors, length, backing_length; 2097 int n, ro, open_flags; 2098 int ret = 0; 2099 uint8_t *buf = NULL; 2100 char filename[PATH_MAX]; 2101 2102 if (!drv) 2103 return -ENOMEDIUM; 2104 2105 if (!bs->backing_hd) { 2106 return -ENOTSUP; 2107 } 2108 2109 if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) { 2110 return -EBUSY; 2111 } 2112 2113 ro = bs->backing_hd->read_only; 2114 /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */ 2115 pstrcpy(filename, sizeof(filename), bs->backing_hd->filename); 2116 open_flags = bs->backing_hd->open_flags; 2117 2118 if (ro) { 2119 if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) { 2120 return -EACCES; 2121 } 2122 } 2123 2124 length = bdrv_getlength(bs); 2125 if (length < 0) { 2126 ret = length; 2127 goto ro_cleanup; 2128 } 2129 2130 backing_length = bdrv_getlength(bs->backing_hd); 2131 if (backing_length < 0) { 2132 ret = backing_length; 2133 goto ro_cleanup; 2134 } 2135 2136 /* If our top snapshot is larger than the backing file image, 2137 * grow the backing file image if possible. If not possible, 2138 * we must return an error */ 2139 if (length > backing_length) { 2140 ret = bdrv_truncate(bs->backing_hd, length); 2141 if (ret < 0) { 2142 goto ro_cleanup; 2143 } 2144 } 2145 2146 total_sectors = length >> BDRV_SECTOR_BITS; 2147 buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE); 2148 2149 for (sector = 0; sector < total_sectors; sector += n) { 2150 ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n); 2151 if (ret < 0) { 2152 goto ro_cleanup; 2153 } 2154 if (ret) { 2155 ret = bdrv_read(bs, sector, buf, n); 2156 if (ret < 0) { 2157 goto ro_cleanup; 2158 } 2159 2160 ret = bdrv_write(bs->backing_hd, sector, buf, n); 2161 if (ret < 0) { 2162 goto ro_cleanup; 2163 } 2164 } 2165 } 2166 2167 if (drv->bdrv_make_empty) { 2168 ret = drv->bdrv_make_empty(bs); 2169 if (ret < 0) { 2170 goto ro_cleanup; 2171 } 2172 bdrv_flush(bs); 2173 } 2174 2175 /* 2176 * Make sure all data we wrote to the backing device is actually 2177 * stable on disk. 2178 */ 2179 if (bs->backing_hd) { 2180 bdrv_flush(bs->backing_hd); 2181 } 2182 2183 ret = 0; 2184 ro_cleanup: 2185 g_free(buf); 2186 2187 if (ro) { 2188 /* ignoring error return here */ 2189 bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL); 2190 } 2191 2192 return ret; 2193 } 2194 2195 int bdrv_commit_all(void) 2196 { 2197 BlockDriverState *bs; 2198 2199 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 2200 if (bs->drv && bs->backing_hd) { 2201 int ret = bdrv_commit(bs); 2202 if (ret < 0) { 2203 return ret; 2204 } 2205 } 2206 } 2207 return 0; 2208 } 2209 2210 /** 2211 * Remove an active request from the tracked requests list 2212 * 2213 * This function should be called when a tracked request is completing. 2214 */ 2215 static void tracked_request_end(BdrvTrackedRequest *req) 2216 { 2217 if (req->serialising) { 2218 req->bs->serialising_in_flight--; 2219 } 2220 2221 QLIST_REMOVE(req, list); 2222 qemu_co_queue_restart_all(&req->wait_queue); 2223 } 2224 2225 /** 2226 * Add an active request to the tracked requests list 2227 */ 2228 static void tracked_request_begin(BdrvTrackedRequest *req, 2229 BlockDriverState *bs, 2230 int64_t offset, 2231 unsigned int bytes, bool is_write) 2232 { 2233 *req = (BdrvTrackedRequest){ 2234 .bs = bs, 2235 .offset = offset, 2236 .bytes = bytes, 2237 .is_write = is_write, 2238 .co = qemu_coroutine_self(), 2239 .serialising = false, 2240 .overlap_offset = offset, 2241 .overlap_bytes = bytes, 2242 }; 2243 2244 qemu_co_queue_init(&req->wait_queue); 2245 2246 QLIST_INSERT_HEAD(&bs->tracked_requests, req, list); 2247 } 2248 2249 static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align) 2250 { 2251 int64_t overlap_offset = req->offset & ~(align - 1); 2252 unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align) 2253 - overlap_offset; 2254 2255 if (!req->serialising) { 2256 req->bs->serialising_in_flight++; 2257 req->serialising = true; 2258 } 2259 2260 req->overlap_offset = MIN(req->overlap_offset, overlap_offset); 2261 req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes); 2262 } 2263 2264 /** 2265 * Round a region to cluster boundaries 2266 */ 2267 void bdrv_round_to_clusters(BlockDriverState *bs, 2268 int64_t sector_num, int nb_sectors, 2269 int64_t *cluster_sector_num, 2270 int *cluster_nb_sectors) 2271 { 2272 BlockDriverInfo bdi; 2273 2274 if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) { 2275 *cluster_sector_num = sector_num; 2276 *cluster_nb_sectors = nb_sectors; 2277 } else { 2278 int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE; 2279 *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c); 2280 *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num + 2281 nb_sectors, c); 2282 } 2283 } 2284 2285 static int bdrv_get_cluster_size(BlockDriverState *bs) 2286 { 2287 BlockDriverInfo bdi; 2288 int ret; 2289 2290 ret = bdrv_get_info(bs, &bdi); 2291 if (ret < 0 || bdi.cluster_size == 0) { 2292 return bs->request_alignment; 2293 } else { 2294 return bdi.cluster_size; 2295 } 2296 } 2297 2298 static bool tracked_request_overlaps(BdrvTrackedRequest *req, 2299 int64_t offset, unsigned int bytes) 2300 { 2301 /* aaaa bbbb */ 2302 if (offset >= req->overlap_offset + req->overlap_bytes) { 2303 return false; 2304 } 2305 /* bbbb aaaa */ 2306 if (req->overlap_offset >= offset + bytes) { 2307 return false; 2308 } 2309 return true; 2310 } 2311 2312 static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self) 2313 { 2314 BlockDriverState *bs = self->bs; 2315 BdrvTrackedRequest *req; 2316 bool retry; 2317 bool waited = false; 2318 2319 if (!bs->serialising_in_flight) { 2320 return false; 2321 } 2322 2323 do { 2324 retry = false; 2325 QLIST_FOREACH(req, &bs->tracked_requests, list) { 2326 if (req == self || (!req->serialising && !self->serialising)) { 2327 continue; 2328 } 2329 if (tracked_request_overlaps(req, self->overlap_offset, 2330 self->overlap_bytes)) 2331 { 2332 /* Hitting this means there was a reentrant request, for 2333 * example, a block driver issuing nested requests. This must 2334 * never happen since it means deadlock. 2335 */ 2336 assert(qemu_coroutine_self() != req->co); 2337 2338 /* If the request is already (indirectly) waiting for us, or 2339 * will wait for us as soon as it wakes up, then just go on 2340 * (instead of producing a deadlock in the former case). */ 2341 if (!req->waiting_for) { 2342 self->waiting_for = req; 2343 qemu_co_queue_wait(&req->wait_queue); 2344 self->waiting_for = NULL; 2345 retry = true; 2346 waited = true; 2347 break; 2348 } 2349 } 2350 } 2351 } while (retry); 2352 2353 return waited; 2354 } 2355 2356 /* 2357 * Return values: 2358 * 0 - success 2359 * -EINVAL - backing format specified, but no file 2360 * -ENOSPC - can't update the backing file because no space is left in the 2361 * image file header 2362 * -ENOTSUP - format driver doesn't support changing the backing file 2363 */ 2364 int bdrv_change_backing_file(BlockDriverState *bs, 2365 const char *backing_file, const char *backing_fmt) 2366 { 2367 BlockDriver *drv = bs->drv; 2368 int ret; 2369 2370 /* Backing file format doesn't make sense without a backing file */ 2371 if (backing_fmt && !backing_file) { 2372 return -EINVAL; 2373 } 2374 2375 if (drv->bdrv_change_backing_file != NULL) { 2376 ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt); 2377 } else { 2378 ret = -ENOTSUP; 2379 } 2380 2381 if (ret == 0) { 2382 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2383 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2384 } 2385 return ret; 2386 } 2387 2388 /* 2389 * Finds the image layer in the chain that has 'bs' as its backing file. 2390 * 2391 * active is the current topmost image. 2392 * 2393 * Returns NULL if bs is not found in active's image chain, 2394 * or if active == bs. 2395 */ 2396 BlockDriverState *bdrv_find_overlay(BlockDriverState *active, 2397 BlockDriverState *bs) 2398 { 2399 BlockDriverState *overlay = NULL; 2400 BlockDriverState *intermediate; 2401 2402 assert(active != NULL); 2403 assert(bs != NULL); 2404 2405 /* if bs is the same as active, then by definition it has no overlay 2406 */ 2407 if (active == bs) { 2408 return NULL; 2409 } 2410 2411 intermediate = active; 2412 while (intermediate->backing_hd) { 2413 if (intermediate->backing_hd == bs) { 2414 overlay = intermediate; 2415 break; 2416 } 2417 intermediate = intermediate->backing_hd; 2418 } 2419 2420 return overlay; 2421 } 2422 2423 typedef struct BlkIntermediateStates { 2424 BlockDriverState *bs; 2425 QSIMPLEQ_ENTRY(BlkIntermediateStates) entry; 2426 } BlkIntermediateStates; 2427 2428 2429 /* 2430 * Drops images above 'base' up to and including 'top', and sets the image 2431 * above 'top' to have base as its backing file. 2432 * 2433 * Requires that the overlay to 'top' is opened r/w, so that the backing file 2434 * information in 'bs' can be properly updated. 2435 * 2436 * E.g., this will convert the following chain: 2437 * bottom <- base <- intermediate <- top <- active 2438 * 2439 * to 2440 * 2441 * bottom <- base <- active 2442 * 2443 * It is allowed for bottom==base, in which case it converts: 2444 * 2445 * base <- intermediate <- top <- active 2446 * 2447 * to 2448 * 2449 * base <- active 2450 * 2451 * Error conditions: 2452 * if active == top, that is considered an error 2453 * 2454 */ 2455 int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top, 2456 BlockDriverState *base) 2457 { 2458 BlockDriverState *intermediate; 2459 BlockDriverState *base_bs = NULL; 2460 BlockDriverState *new_top_bs = NULL; 2461 BlkIntermediateStates *intermediate_state, *next; 2462 int ret = -EIO; 2463 2464 QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete; 2465 QSIMPLEQ_INIT(&states_to_delete); 2466 2467 if (!top->drv || !base->drv) { 2468 goto exit; 2469 } 2470 2471 new_top_bs = bdrv_find_overlay(active, top); 2472 2473 if (new_top_bs == NULL) { 2474 /* we could not find the image above 'top', this is an error */ 2475 goto exit; 2476 } 2477 2478 /* special case of new_top_bs->backing_hd already pointing to base - nothing 2479 * to do, no intermediate images */ 2480 if (new_top_bs->backing_hd == base) { 2481 ret = 0; 2482 goto exit; 2483 } 2484 2485 intermediate = top; 2486 2487 /* now we will go down through the list, and add each BDS we find 2488 * into our deletion queue, until we hit the 'base' 2489 */ 2490 while (intermediate) { 2491 intermediate_state = g_malloc0(sizeof(BlkIntermediateStates)); 2492 intermediate_state->bs = intermediate; 2493 QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry); 2494 2495 if (intermediate->backing_hd == base) { 2496 base_bs = intermediate->backing_hd; 2497 break; 2498 } 2499 intermediate = intermediate->backing_hd; 2500 } 2501 if (base_bs == NULL) { 2502 /* something went wrong, we did not end at the base. safely 2503 * unravel everything, and exit with error */ 2504 goto exit; 2505 } 2506 2507 /* success - we can delete the intermediate states, and link top->base */ 2508 ret = bdrv_change_backing_file(new_top_bs, base_bs->filename, 2509 base_bs->drv ? base_bs->drv->format_name : ""); 2510 if (ret) { 2511 goto exit; 2512 } 2513 new_top_bs->backing_hd = base_bs; 2514 2515 bdrv_refresh_limits(new_top_bs); 2516 2517 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2518 /* so that bdrv_close() does not recursively close the chain */ 2519 intermediate_state->bs->backing_hd = NULL; 2520 bdrv_unref(intermediate_state->bs); 2521 } 2522 ret = 0; 2523 2524 exit: 2525 QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) { 2526 g_free(intermediate_state); 2527 } 2528 return ret; 2529 } 2530 2531 2532 static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset, 2533 size_t size) 2534 { 2535 int64_t len; 2536 2537 if (!bdrv_is_inserted(bs)) 2538 return -ENOMEDIUM; 2539 2540 if (bs->growable) 2541 return 0; 2542 2543 len = bdrv_getlength(bs); 2544 2545 if (offset < 0) 2546 return -EIO; 2547 2548 if ((offset > len) || (len - offset < size)) 2549 return -EIO; 2550 2551 return 0; 2552 } 2553 2554 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num, 2555 int nb_sectors) 2556 { 2557 return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE, 2558 nb_sectors * BDRV_SECTOR_SIZE); 2559 } 2560 2561 typedef struct RwCo { 2562 BlockDriverState *bs; 2563 int64_t offset; 2564 QEMUIOVector *qiov; 2565 bool is_write; 2566 int ret; 2567 BdrvRequestFlags flags; 2568 } RwCo; 2569 2570 static void coroutine_fn bdrv_rw_co_entry(void *opaque) 2571 { 2572 RwCo *rwco = opaque; 2573 2574 if (!rwco->is_write) { 2575 rwco->ret = bdrv_co_do_preadv(rwco->bs, rwco->offset, 2576 rwco->qiov->size, rwco->qiov, 2577 rwco->flags); 2578 } else { 2579 rwco->ret = bdrv_co_do_pwritev(rwco->bs, rwco->offset, 2580 rwco->qiov->size, rwco->qiov, 2581 rwco->flags); 2582 } 2583 } 2584 2585 /* 2586 * Process a vectored synchronous request using coroutines 2587 */ 2588 static int bdrv_prwv_co(BlockDriverState *bs, int64_t offset, 2589 QEMUIOVector *qiov, bool is_write, 2590 BdrvRequestFlags flags) 2591 { 2592 Coroutine *co; 2593 RwCo rwco = { 2594 .bs = bs, 2595 .offset = offset, 2596 .qiov = qiov, 2597 .is_write = is_write, 2598 .ret = NOT_DONE, 2599 .flags = flags, 2600 }; 2601 2602 /** 2603 * In sync call context, when the vcpu is blocked, this throttling timer 2604 * will not fire; so the I/O throttling function has to be disabled here 2605 * if it has been enabled. 2606 */ 2607 if (bs->io_limits_enabled) { 2608 fprintf(stderr, "Disabling I/O throttling on '%s' due " 2609 "to synchronous I/O.\n", bdrv_get_device_name(bs)); 2610 bdrv_io_limits_disable(bs); 2611 } 2612 2613 if (qemu_in_coroutine()) { 2614 /* Fast-path if already in coroutine context */ 2615 bdrv_rw_co_entry(&rwco); 2616 } else { 2617 co = qemu_coroutine_create(bdrv_rw_co_entry); 2618 qemu_coroutine_enter(co, &rwco); 2619 while (rwco.ret == NOT_DONE) { 2620 qemu_aio_wait(); 2621 } 2622 } 2623 return rwco.ret; 2624 } 2625 2626 /* 2627 * Process a synchronous request using coroutines 2628 */ 2629 static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf, 2630 int nb_sectors, bool is_write, BdrvRequestFlags flags) 2631 { 2632 QEMUIOVector qiov; 2633 struct iovec iov = { 2634 .iov_base = (void *)buf, 2635 .iov_len = nb_sectors * BDRV_SECTOR_SIZE, 2636 }; 2637 2638 qemu_iovec_init_external(&qiov, &iov, 1); 2639 return bdrv_prwv_co(bs, sector_num << BDRV_SECTOR_BITS, 2640 &qiov, is_write, flags); 2641 } 2642 2643 /* return < 0 if error. See bdrv_write() for the return codes */ 2644 int bdrv_read(BlockDriverState *bs, int64_t sector_num, 2645 uint8_t *buf, int nb_sectors) 2646 { 2647 return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0); 2648 } 2649 2650 /* Just like bdrv_read(), but with I/O throttling temporarily disabled */ 2651 int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num, 2652 uint8_t *buf, int nb_sectors) 2653 { 2654 bool enabled; 2655 int ret; 2656 2657 enabled = bs->io_limits_enabled; 2658 bs->io_limits_enabled = false; 2659 ret = bdrv_read(bs, sector_num, buf, nb_sectors); 2660 bs->io_limits_enabled = enabled; 2661 return ret; 2662 } 2663 2664 /* Return < 0 if error. Important errors are: 2665 -EIO generic I/O error (may happen for all errors) 2666 -ENOMEDIUM No media inserted. 2667 -EINVAL Invalid sector number or nb_sectors 2668 -EACCES Trying to write a read-only device 2669 */ 2670 int bdrv_write(BlockDriverState *bs, int64_t sector_num, 2671 const uint8_t *buf, int nb_sectors) 2672 { 2673 return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0); 2674 } 2675 2676 int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num, 2677 int nb_sectors, BdrvRequestFlags flags) 2678 { 2679 return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true, 2680 BDRV_REQ_ZERO_WRITE | flags); 2681 } 2682 2683 /* 2684 * Completely zero out a block device with the help of bdrv_write_zeroes. 2685 * The operation is sped up by checking the block status and only writing 2686 * zeroes to the device if they currently do not return zeroes. Optional 2687 * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP). 2688 * 2689 * Returns < 0 on error, 0 on success. For error codes see bdrv_write(). 2690 */ 2691 int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags) 2692 { 2693 int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE; 2694 int64_t ret, nb_sectors, sector_num = 0; 2695 int n; 2696 2697 for (;;) { 2698 nb_sectors = target_size - sector_num; 2699 if (nb_sectors <= 0) { 2700 return 0; 2701 } 2702 if (nb_sectors > INT_MAX) { 2703 nb_sectors = INT_MAX; 2704 } 2705 ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n); 2706 if (ret < 0) { 2707 error_report("error getting block status at sector %" PRId64 ": %s", 2708 sector_num, strerror(-ret)); 2709 return ret; 2710 } 2711 if (ret & BDRV_BLOCK_ZERO) { 2712 sector_num += n; 2713 continue; 2714 } 2715 ret = bdrv_write_zeroes(bs, sector_num, n, flags); 2716 if (ret < 0) { 2717 error_report("error writing zeroes at sector %" PRId64 ": %s", 2718 sector_num, strerror(-ret)); 2719 return ret; 2720 } 2721 sector_num += n; 2722 } 2723 } 2724 2725 int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int bytes) 2726 { 2727 QEMUIOVector qiov; 2728 struct iovec iov = { 2729 .iov_base = (void *)buf, 2730 .iov_len = bytes, 2731 }; 2732 int ret; 2733 2734 if (bytes < 0) { 2735 return -EINVAL; 2736 } 2737 2738 qemu_iovec_init_external(&qiov, &iov, 1); 2739 ret = bdrv_prwv_co(bs, offset, &qiov, false, 0); 2740 if (ret < 0) { 2741 return ret; 2742 } 2743 2744 return bytes; 2745 } 2746 2747 int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov) 2748 { 2749 int ret; 2750 2751 ret = bdrv_prwv_co(bs, offset, qiov, true, 0); 2752 if (ret < 0) { 2753 return ret; 2754 } 2755 2756 return qiov->size; 2757 } 2758 2759 int bdrv_pwrite(BlockDriverState *bs, int64_t offset, 2760 const void *buf, int bytes) 2761 { 2762 QEMUIOVector qiov; 2763 struct iovec iov = { 2764 .iov_base = (void *) buf, 2765 .iov_len = bytes, 2766 }; 2767 2768 if (bytes < 0) { 2769 return -EINVAL; 2770 } 2771 2772 qemu_iovec_init_external(&qiov, &iov, 1); 2773 return bdrv_pwritev(bs, offset, &qiov); 2774 } 2775 2776 /* 2777 * Writes to the file and ensures that no writes are reordered across this 2778 * request (acts as a barrier) 2779 * 2780 * Returns 0 on success, -errno in error cases. 2781 */ 2782 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, 2783 const void *buf, int count) 2784 { 2785 int ret; 2786 2787 ret = bdrv_pwrite(bs, offset, buf, count); 2788 if (ret < 0) { 2789 return ret; 2790 } 2791 2792 /* No flush needed for cache modes that already do it */ 2793 if (bs->enable_write_cache) { 2794 bdrv_flush(bs); 2795 } 2796 2797 return 0; 2798 } 2799 2800 static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, 2801 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) 2802 { 2803 /* Perform I/O through a temporary buffer so that users who scribble over 2804 * their read buffer while the operation is in progress do not end up 2805 * modifying the image file. This is critical for zero-copy guest I/O 2806 * where anything might happen inside guest memory. 2807 */ 2808 void *bounce_buffer; 2809 2810 BlockDriver *drv = bs->drv; 2811 struct iovec iov; 2812 QEMUIOVector bounce_qiov; 2813 int64_t cluster_sector_num; 2814 int cluster_nb_sectors; 2815 size_t skip_bytes; 2816 int ret; 2817 2818 /* Cover entire cluster so no additional backing file I/O is required when 2819 * allocating cluster in the image file. 2820 */ 2821 bdrv_round_to_clusters(bs, sector_num, nb_sectors, 2822 &cluster_sector_num, &cluster_nb_sectors); 2823 2824 trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, 2825 cluster_sector_num, cluster_nb_sectors); 2826 2827 iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE; 2828 iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len); 2829 qemu_iovec_init_external(&bounce_qiov, &iov, 1); 2830 2831 ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors, 2832 &bounce_qiov); 2833 if (ret < 0) { 2834 goto err; 2835 } 2836 2837 if (drv->bdrv_co_write_zeroes && 2838 buffer_is_zero(bounce_buffer, iov.iov_len)) { 2839 ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num, 2840 cluster_nb_sectors, 0); 2841 } else { 2842 /* This does not change the data on the disk, it is not necessary 2843 * to flush even in cache=writethrough mode. 2844 */ 2845 ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors, 2846 &bounce_qiov); 2847 } 2848 2849 if (ret < 0) { 2850 /* It might be okay to ignore write errors for guest requests. If this 2851 * is a deliberate copy-on-read then we don't want to ignore the error. 2852 * Simply report it in all cases. 2853 */ 2854 goto err; 2855 } 2856 2857 skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE; 2858 qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes, 2859 nb_sectors * BDRV_SECTOR_SIZE); 2860 2861 err: 2862 qemu_vfree(bounce_buffer); 2863 return ret; 2864 } 2865 2866 /* 2867 * Forwards an already correctly aligned request to the BlockDriver. This 2868 * handles copy on read and zeroing after EOF; any other features must be 2869 * implemented by the caller. 2870 */ 2871 static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs, 2872 BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, 2873 int64_t align, QEMUIOVector *qiov, int flags) 2874 { 2875 BlockDriver *drv = bs->drv; 2876 int ret; 2877 2878 int64_t sector_num = offset >> BDRV_SECTOR_BITS; 2879 unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; 2880 2881 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 2882 assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 2883 2884 /* Handle Copy on Read and associated serialisation */ 2885 if (flags & BDRV_REQ_COPY_ON_READ) { 2886 /* If we touch the same cluster it counts as an overlap. This 2887 * guarantees that allocating writes will be serialized and not race 2888 * with each other for the same cluster. For example, in copy-on-read 2889 * it ensures that the CoR read and write operations are atomic and 2890 * guest writes cannot interleave between them. */ 2891 mark_request_serialising(req, bdrv_get_cluster_size(bs)); 2892 } 2893 2894 wait_serialising_requests(req); 2895 2896 if (flags & BDRV_REQ_COPY_ON_READ) { 2897 int pnum; 2898 2899 ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum); 2900 if (ret < 0) { 2901 goto out; 2902 } 2903 2904 if (!ret || pnum != nb_sectors) { 2905 ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov); 2906 goto out; 2907 } 2908 } 2909 2910 /* Forward the request to the BlockDriver */ 2911 if (!(bs->zero_beyond_eof && bs->growable)) { 2912 ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); 2913 } else { 2914 /* Read zeros after EOF of growable BDSes */ 2915 int64_t len, total_sectors, max_nb_sectors; 2916 2917 len = bdrv_getlength(bs); 2918 if (len < 0) { 2919 ret = len; 2920 goto out; 2921 } 2922 2923 total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE); 2924 max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num), 2925 align >> BDRV_SECTOR_BITS); 2926 if (max_nb_sectors > 0) { 2927 ret = drv->bdrv_co_readv(bs, sector_num, 2928 MIN(nb_sectors, max_nb_sectors), qiov); 2929 } else { 2930 ret = 0; 2931 } 2932 2933 /* Reading beyond end of file is supposed to produce zeroes */ 2934 if (ret == 0 && total_sectors < sector_num + nb_sectors) { 2935 uint64_t offset = MAX(0, total_sectors - sector_num); 2936 uint64_t bytes = (sector_num + nb_sectors - offset) * 2937 BDRV_SECTOR_SIZE; 2938 qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes); 2939 } 2940 } 2941 2942 out: 2943 return ret; 2944 } 2945 2946 /* 2947 * Handle a read request in coroutine context 2948 */ 2949 static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs, 2950 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 2951 BdrvRequestFlags flags) 2952 { 2953 BlockDriver *drv = bs->drv; 2954 BdrvTrackedRequest req; 2955 2956 /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ 2957 uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); 2958 uint8_t *head_buf = NULL; 2959 uint8_t *tail_buf = NULL; 2960 QEMUIOVector local_qiov; 2961 bool use_local_qiov = false; 2962 int ret; 2963 2964 if (!drv) { 2965 return -ENOMEDIUM; 2966 } 2967 if (bdrv_check_byte_request(bs, offset, bytes)) { 2968 return -EIO; 2969 } 2970 2971 if (bs->copy_on_read) { 2972 flags |= BDRV_REQ_COPY_ON_READ; 2973 } 2974 2975 /* throttling disk I/O */ 2976 if (bs->io_limits_enabled) { 2977 bdrv_io_limits_intercept(bs, bytes, false); 2978 } 2979 2980 /* Align read if necessary by padding qiov */ 2981 if (offset & (align - 1)) { 2982 head_buf = qemu_blockalign(bs, align); 2983 qemu_iovec_init(&local_qiov, qiov->niov + 2); 2984 qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); 2985 qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); 2986 use_local_qiov = true; 2987 2988 bytes += offset & (align - 1); 2989 offset = offset & ~(align - 1); 2990 } 2991 2992 if ((offset + bytes) & (align - 1)) { 2993 if (!use_local_qiov) { 2994 qemu_iovec_init(&local_qiov, qiov->niov + 1); 2995 qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); 2996 use_local_qiov = true; 2997 } 2998 tail_buf = qemu_blockalign(bs, align); 2999 qemu_iovec_add(&local_qiov, tail_buf, 3000 align - ((offset + bytes) & (align - 1))); 3001 3002 bytes = ROUND_UP(bytes, align); 3003 } 3004 3005 tracked_request_begin(&req, bs, offset, bytes, false); 3006 ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align, 3007 use_local_qiov ? &local_qiov : qiov, 3008 flags); 3009 tracked_request_end(&req); 3010 3011 if (use_local_qiov) { 3012 qemu_iovec_destroy(&local_qiov); 3013 qemu_vfree(head_buf); 3014 qemu_vfree(tail_buf); 3015 } 3016 3017 return ret; 3018 } 3019 3020 static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs, 3021 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 3022 BdrvRequestFlags flags) 3023 { 3024 if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) { 3025 return -EINVAL; 3026 } 3027 3028 return bdrv_co_do_preadv(bs, sector_num << BDRV_SECTOR_BITS, 3029 nb_sectors << BDRV_SECTOR_BITS, qiov, flags); 3030 } 3031 3032 int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num, 3033 int nb_sectors, QEMUIOVector *qiov) 3034 { 3035 trace_bdrv_co_readv(bs, sector_num, nb_sectors); 3036 3037 return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0); 3038 } 3039 3040 int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs, 3041 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) 3042 { 3043 trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors); 3044 3045 return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 3046 BDRV_REQ_COPY_ON_READ); 3047 } 3048 3049 /* if no limit is specified in the BlockLimits use a default 3050 * of 32768 512-byte sectors (16 MiB) per request. 3051 */ 3052 #define MAX_WRITE_ZEROES_DEFAULT 32768 3053 3054 static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs, 3055 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 3056 { 3057 BlockDriver *drv = bs->drv; 3058 QEMUIOVector qiov; 3059 struct iovec iov = {0}; 3060 int ret = 0; 3061 3062 int max_write_zeroes = bs->bl.max_write_zeroes ? 3063 bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT; 3064 3065 while (nb_sectors > 0 && !ret) { 3066 int num = nb_sectors; 3067 3068 /* Align request. Block drivers can expect the "bulk" of the request 3069 * to be aligned. 3070 */ 3071 if (bs->bl.write_zeroes_alignment 3072 && num > bs->bl.write_zeroes_alignment) { 3073 if (sector_num % bs->bl.write_zeroes_alignment != 0) { 3074 /* Make a small request up to the first aligned sector. */ 3075 num = bs->bl.write_zeroes_alignment; 3076 num -= sector_num % bs->bl.write_zeroes_alignment; 3077 } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) { 3078 /* Shorten the request to the last aligned sector. num cannot 3079 * underflow because num > bs->bl.write_zeroes_alignment. 3080 */ 3081 num -= (sector_num + num) % bs->bl.write_zeroes_alignment; 3082 } 3083 } 3084 3085 /* limit request size */ 3086 if (num > max_write_zeroes) { 3087 num = max_write_zeroes; 3088 } 3089 3090 ret = -ENOTSUP; 3091 /* First try the efficient write zeroes operation */ 3092 if (drv->bdrv_co_write_zeroes) { 3093 ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags); 3094 } 3095 3096 if (ret == -ENOTSUP) { 3097 /* Fall back to bounce buffer if write zeroes is unsupported */ 3098 iov.iov_len = num * BDRV_SECTOR_SIZE; 3099 if (iov.iov_base == NULL) { 3100 iov.iov_base = qemu_blockalign(bs, num * BDRV_SECTOR_SIZE); 3101 memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE); 3102 } 3103 qemu_iovec_init_external(&qiov, &iov, 1); 3104 3105 ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov); 3106 3107 /* Keep bounce buffer around if it is big enough for all 3108 * all future requests. 3109 */ 3110 if (num < max_write_zeroes) { 3111 qemu_vfree(iov.iov_base); 3112 iov.iov_base = NULL; 3113 } 3114 } 3115 3116 sector_num += num; 3117 nb_sectors -= num; 3118 } 3119 3120 qemu_vfree(iov.iov_base); 3121 return ret; 3122 } 3123 3124 /* 3125 * Forwards an already correctly aligned write request to the BlockDriver. 3126 */ 3127 static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs, 3128 BdrvTrackedRequest *req, int64_t offset, unsigned int bytes, 3129 QEMUIOVector *qiov, int flags) 3130 { 3131 BlockDriver *drv = bs->drv; 3132 bool waited; 3133 int ret; 3134 3135 int64_t sector_num = offset >> BDRV_SECTOR_BITS; 3136 unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS; 3137 3138 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 3139 assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 3140 3141 waited = wait_serialising_requests(req); 3142 assert(!waited || !req->serialising); 3143 assert(req->overlap_offset <= offset); 3144 assert(offset + bytes <= req->overlap_offset + req->overlap_bytes); 3145 3146 ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req); 3147 3148 if (ret < 0) { 3149 /* Do nothing, write notifier decided to fail this request */ 3150 } else if (flags & BDRV_REQ_ZERO_WRITE) { 3151 BLKDBG_EVENT(bs, BLKDBG_PWRITEV_ZERO); 3152 ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags); 3153 } else { 3154 BLKDBG_EVENT(bs, BLKDBG_PWRITEV); 3155 ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov); 3156 } 3157 BLKDBG_EVENT(bs, BLKDBG_PWRITEV_DONE); 3158 3159 if (ret == 0 && !bs->enable_write_cache) { 3160 ret = bdrv_co_flush(bs); 3161 } 3162 3163 bdrv_set_dirty(bs, sector_num, nb_sectors); 3164 3165 if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { 3166 bs->wr_highest_sector = sector_num + nb_sectors - 1; 3167 } 3168 if (bs->growable && ret >= 0) { 3169 bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors); 3170 } 3171 3172 return ret; 3173 } 3174 3175 /* 3176 * Handle a write request in coroutine context 3177 */ 3178 static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs, 3179 int64_t offset, unsigned int bytes, QEMUIOVector *qiov, 3180 BdrvRequestFlags flags) 3181 { 3182 BdrvTrackedRequest req; 3183 /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */ 3184 uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment); 3185 uint8_t *head_buf = NULL; 3186 uint8_t *tail_buf = NULL; 3187 QEMUIOVector local_qiov; 3188 bool use_local_qiov = false; 3189 int ret; 3190 3191 if (!bs->drv) { 3192 return -ENOMEDIUM; 3193 } 3194 if (bs->read_only) { 3195 return -EACCES; 3196 } 3197 if (bdrv_check_byte_request(bs, offset, bytes)) { 3198 return -EIO; 3199 } 3200 3201 /* throttling disk I/O */ 3202 if (bs->io_limits_enabled) { 3203 bdrv_io_limits_intercept(bs, bytes, true); 3204 } 3205 3206 /* 3207 * Align write if necessary by performing a read-modify-write cycle. 3208 * Pad qiov with the read parts and be sure to have a tracked request not 3209 * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle. 3210 */ 3211 tracked_request_begin(&req, bs, offset, bytes, true); 3212 3213 if (offset & (align - 1)) { 3214 QEMUIOVector head_qiov; 3215 struct iovec head_iov; 3216 3217 mark_request_serialising(&req, align); 3218 wait_serialising_requests(&req); 3219 3220 head_buf = qemu_blockalign(bs, align); 3221 head_iov = (struct iovec) { 3222 .iov_base = head_buf, 3223 .iov_len = align, 3224 }; 3225 qemu_iovec_init_external(&head_qiov, &head_iov, 1); 3226 3227 BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD); 3228 ret = bdrv_aligned_preadv(bs, &req, offset & ~(align - 1), align, 3229 align, &head_qiov, 0); 3230 if (ret < 0) { 3231 goto fail; 3232 } 3233 BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD); 3234 3235 qemu_iovec_init(&local_qiov, qiov->niov + 2); 3236 qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1)); 3237 qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); 3238 use_local_qiov = true; 3239 3240 bytes += offset & (align - 1); 3241 offset = offset & ~(align - 1); 3242 } 3243 3244 if ((offset + bytes) & (align - 1)) { 3245 QEMUIOVector tail_qiov; 3246 struct iovec tail_iov; 3247 size_t tail_bytes; 3248 bool waited; 3249 3250 mark_request_serialising(&req, align); 3251 waited = wait_serialising_requests(&req); 3252 assert(!waited || !use_local_qiov); 3253 3254 tail_buf = qemu_blockalign(bs, align); 3255 tail_iov = (struct iovec) { 3256 .iov_base = tail_buf, 3257 .iov_len = align, 3258 }; 3259 qemu_iovec_init_external(&tail_qiov, &tail_iov, 1); 3260 3261 BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL); 3262 ret = bdrv_aligned_preadv(bs, &req, (offset + bytes) & ~(align - 1), align, 3263 align, &tail_qiov, 0); 3264 if (ret < 0) { 3265 goto fail; 3266 } 3267 BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL); 3268 3269 if (!use_local_qiov) { 3270 qemu_iovec_init(&local_qiov, qiov->niov + 1); 3271 qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size); 3272 use_local_qiov = true; 3273 } 3274 3275 tail_bytes = (offset + bytes) & (align - 1); 3276 qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes); 3277 3278 bytes = ROUND_UP(bytes, align); 3279 } 3280 3281 ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, 3282 use_local_qiov ? &local_qiov : qiov, 3283 flags); 3284 3285 fail: 3286 tracked_request_end(&req); 3287 3288 if (use_local_qiov) { 3289 qemu_iovec_destroy(&local_qiov); 3290 } 3291 qemu_vfree(head_buf); 3292 qemu_vfree(tail_buf); 3293 3294 return ret; 3295 } 3296 3297 static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 3298 int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, 3299 BdrvRequestFlags flags) 3300 { 3301 if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) { 3302 return -EINVAL; 3303 } 3304 3305 return bdrv_co_do_pwritev(bs, sector_num << BDRV_SECTOR_BITS, 3306 nb_sectors << BDRV_SECTOR_BITS, qiov, flags); 3307 } 3308 3309 int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num, 3310 int nb_sectors, QEMUIOVector *qiov) 3311 { 3312 trace_bdrv_co_writev(bs, sector_num, nb_sectors); 3313 3314 return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0); 3315 } 3316 3317 int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, 3318 int64_t sector_num, int nb_sectors, 3319 BdrvRequestFlags flags) 3320 { 3321 trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags); 3322 3323 if (!(bs->open_flags & BDRV_O_UNMAP)) { 3324 flags &= ~BDRV_REQ_MAY_UNMAP; 3325 } 3326 3327 return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL, 3328 BDRV_REQ_ZERO_WRITE | flags); 3329 } 3330 3331 /** 3332 * Truncate file to 'offset' bytes (needed only for file protocols) 3333 */ 3334 int bdrv_truncate(BlockDriverState *bs, int64_t offset) 3335 { 3336 BlockDriver *drv = bs->drv; 3337 int ret; 3338 if (!drv) 3339 return -ENOMEDIUM; 3340 if (!drv->bdrv_truncate) 3341 return -ENOTSUP; 3342 if (bs->read_only) 3343 return -EACCES; 3344 if (bdrv_in_use(bs)) 3345 return -EBUSY; 3346 ret = drv->bdrv_truncate(bs, offset); 3347 if (ret == 0) { 3348 ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); 3349 bdrv_dev_resize_cb(bs); 3350 } 3351 return ret; 3352 } 3353 3354 /** 3355 * Length of a allocated file in bytes. Sparse files are counted by actual 3356 * allocated space. Return < 0 if error or unknown. 3357 */ 3358 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs) 3359 { 3360 BlockDriver *drv = bs->drv; 3361 if (!drv) { 3362 return -ENOMEDIUM; 3363 } 3364 if (drv->bdrv_get_allocated_file_size) { 3365 return drv->bdrv_get_allocated_file_size(bs); 3366 } 3367 if (bs->file) { 3368 return bdrv_get_allocated_file_size(bs->file); 3369 } 3370 return -ENOTSUP; 3371 } 3372 3373 /** 3374 * Length of a file in bytes. Return < 0 if error or unknown. 3375 */ 3376 int64_t bdrv_getlength(BlockDriverState *bs) 3377 { 3378 BlockDriver *drv = bs->drv; 3379 if (!drv) 3380 return -ENOMEDIUM; 3381 3382 if (drv->has_variable_length) { 3383 int ret = refresh_total_sectors(bs, bs->total_sectors); 3384 if (ret < 0) { 3385 return ret; 3386 } 3387 } 3388 return bs->total_sectors * BDRV_SECTOR_SIZE; 3389 } 3390 3391 /* return 0 as number of sectors if no device present or error */ 3392 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr) 3393 { 3394 int64_t length; 3395 length = bdrv_getlength(bs); 3396 if (length < 0) 3397 length = 0; 3398 else 3399 length = length >> BDRV_SECTOR_BITS; 3400 *nb_sectors_ptr = length; 3401 } 3402 3403 void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error, 3404 BlockdevOnError on_write_error) 3405 { 3406 bs->on_read_error = on_read_error; 3407 bs->on_write_error = on_write_error; 3408 } 3409 3410 BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read) 3411 { 3412 return is_read ? bs->on_read_error : bs->on_write_error; 3413 } 3414 3415 BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error) 3416 { 3417 BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error; 3418 3419 switch (on_err) { 3420 case BLOCKDEV_ON_ERROR_ENOSPC: 3421 return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT; 3422 case BLOCKDEV_ON_ERROR_STOP: 3423 return BDRV_ACTION_STOP; 3424 case BLOCKDEV_ON_ERROR_REPORT: 3425 return BDRV_ACTION_REPORT; 3426 case BLOCKDEV_ON_ERROR_IGNORE: 3427 return BDRV_ACTION_IGNORE; 3428 default: 3429 abort(); 3430 } 3431 } 3432 3433 /* This is done by device models because, while the block layer knows 3434 * about the error, it does not know whether an operation comes from 3435 * the device or the block layer (from a job, for example). 3436 */ 3437 void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action, 3438 bool is_read, int error) 3439 { 3440 assert(error >= 0); 3441 bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read); 3442 if (action == BDRV_ACTION_STOP) { 3443 vm_stop(RUN_STATE_IO_ERROR); 3444 bdrv_iostatus_set_err(bs, error); 3445 } 3446 } 3447 3448 int bdrv_is_read_only(BlockDriverState *bs) 3449 { 3450 return bs->read_only; 3451 } 3452 3453 int bdrv_is_sg(BlockDriverState *bs) 3454 { 3455 return bs->sg; 3456 } 3457 3458 int bdrv_enable_write_cache(BlockDriverState *bs) 3459 { 3460 return bs->enable_write_cache; 3461 } 3462 3463 void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce) 3464 { 3465 bs->enable_write_cache = wce; 3466 3467 /* so a reopen() will preserve wce */ 3468 if (wce) { 3469 bs->open_flags |= BDRV_O_CACHE_WB; 3470 } else { 3471 bs->open_flags &= ~BDRV_O_CACHE_WB; 3472 } 3473 } 3474 3475 int bdrv_is_encrypted(BlockDriverState *bs) 3476 { 3477 if (bs->backing_hd && bs->backing_hd->encrypted) 3478 return 1; 3479 return bs->encrypted; 3480 } 3481 3482 int bdrv_key_required(BlockDriverState *bs) 3483 { 3484 BlockDriverState *backing_hd = bs->backing_hd; 3485 3486 if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key) 3487 return 1; 3488 return (bs->encrypted && !bs->valid_key); 3489 } 3490 3491 int bdrv_set_key(BlockDriverState *bs, const char *key) 3492 { 3493 int ret; 3494 if (bs->backing_hd && bs->backing_hd->encrypted) { 3495 ret = bdrv_set_key(bs->backing_hd, key); 3496 if (ret < 0) 3497 return ret; 3498 if (!bs->encrypted) 3499 return 0; 3500 } 3501 if (!bs->encrypted) { 3502 return -EINVAL; 3503 } else if (!bs->drv || !bs->drv->bdrv_set_key) { 3504 return -ENOMEDIUM; 3505 } 3506 ret = bs->drv->bdrv_set_key(bs, key); 3507 if (ret < 0) { 3508 bs->valid_key = 0; 3509 } else if (!bs->valid_key) { 3510 bs->valid_key = 1; 3511 /* call the change callback now, we skipped it on open */ 3512 bdrv_dev_change_media_cb(bs, true); 3513 } 3514 return ret; 3515 } 3516 3517 const char *bdrv_get_format_name(BlockDriverState *bs) 3518 { 3519 return bs->drv ? bs->drv->format_name : NULL; 3520 } 3521 3522 void bdrv_iterate_format(void (*it)(void *opaque, const char *name), 3523 void *opaque) 3524 { 3525 BlockDriver *drv; 3526 3527 QLIST_FOREACH(drv, &bdrv_drivers, list) { 3528 it(opaque, drv->format_name); 3529 } 3530 } 3531 3532 /* This function is to find block backend bs */ 3533 BlockDriverState *bdrv_find(const char *name) 3534 { 3535 BlockDriverState *bs; 3536 3537 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 3538 if (!strcmp(name, bs->device_name)) { 3539 return bs; 3540 } 3541 } 3542 return NULL; 3543 } 3544 3545 /* This function is to find a node in the bs graph */ 3546 BlockDriverState *bdrv_find_node(const char *node_name) 3547 { 3548 BlockDriverState *bs; 3549 3550 assert(node_name); 3551 3552 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3553 if (!strcmp(node_name, bs->node_name)) { 3554 return bs; 3555 } 3556 } 3557 return NULL; 3558 } 3559 3560 /* Put this QMP function here so it can access the static graph_bdrv_states. */ 3561 BlockDeviceInfoList *bdrv_named_nodes_list(void) 3562 { 3563 BlockDeviceInfoList *list, *entry; 3564 BlockDriverState *bs; 3565 3566 list = NULL; 3567 QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) { 3568 entry = g_malloc0(sizeof(*entry)); 3569 entry->value = bdrv_block_device_info(bs); 3570 entry->next = list; 3571 list = entry; 3572 } 3573 3574 return list; 3575 } 3576 3577 BlockDriverState *bdrv_lookup_bs(const char *device, 3578 const char *node_name, 3579 Error **errp) 3580 { 3581 BlockDriverState *bs = NULL; 3582 3583 if (device) { 3584 bs = bdrv_find(device); 3585 3586 if (bs) { 3587 return bs; 3588 } 3589 } 3590 3591 if (node_name) { 3592 bs = bdrv_find_node(node_name); 3593 3594 if (bs) { 3595 return bs; 3596 } 3597 } 3598 3599 error_setg(errp, "Cannot find device=%s nor node_name=%s", 3600 device ? device : "", 3601 node_name ? node_name : ""); 3602 return NULL; 3603 } 3604 3605 BlockDriverState *bdrv_next(BlockDriverState *bs) 3606 { 3607 if (!bs) { 3608 return QTAILQ_FIRST(&bdrv_states); 3609 } 3610 return QTAILQ_NEXT(bs, device_list); 3611 } 3612 3613 void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque) 3614 { 3615 BlockDriverState *bs; 3616 3617 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 3618 it(opaque, bs); 3619 } 3620 } 3621 3622 const char *bdrv_get_device_name(BlockDriverState *bs) 3623 { 3624 return bs->device_name; 3625 } 3626 3627 int bdrv_get_flags(BlockDriverState *bs) 3628 { 3629 return bs->open_flags; 3630 } 3631 3632 int bdrv_flush_all(void) 3633 { 3634 BlockDriverState *bs; 3635 int result = 0; 3636 3637 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 3638 int ret = bdrv_flush(bs); 3639 if (ret < 0 && !result) { 3640 result = ret; 3641 } 3642 } 3643 3644 return result; 3645 } 3646 3647 int bdrv_has_zero_init_1(BlockDriverState *bs) 3648 { 3649 return 1; 3650 } 3651 3652 int bdrv_has_zero_init(BlockDriverState *bs) 3653 { 3654 assert(bs->drv); 3655 3656 /* If BS is a copy on write image, it is initialized to 3657 the contents of the base image, which may not be zeroes. */ 3658 if (bs->backing_hd) { 3659 return 0; 3660 } 3661 if (bs->drv->bdrv_has_zero_init) { 3662 return bs->drv->bdrv_has_zero_init(bs); 3663 } 3664 3665 /* safe default */ 3666 return 0; 3667 } 3668 3669 bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs) 3670 { 3671 BlockDriverInfo bdi; 3672 3673 if (bs->backing_hd) { 3674 return false; 3675 } 3676 3677 if (bdrv_get_info(bs, &bdi) == 0) { 3678 return bdi.unallocated_blocks_are_zero; 3679 } 3680 3681 return false; 3682 } 3683 3684 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs) 3685 { 3686 BlockDriverInfo bdi; 3687 3688 if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) { 3689 return false; 3690 } 3691 3692 if (bdrv_get_info(bs, &bdi) == 0) { 3693 return bdi.can_write_zeroes_with_unmap; 3694 } 3695 3696 return false; 3697 } 3698 3699 typedef struct BdrvCoGetBlockStatusData { 3700 BlockDriverState *bs; 3701 BlockDriverState *base; 3702 int64_t sector_num; 3703 int nb_sectors; 3704 int *pnum; 3705 int64_t ret; 3706 bool done; 3707 } BdrvCoGetBlockStatusData; 3708 3709 /* 3710 * Returns true iff the specified sector is present in the disk image. Drivers 3711 * not implementing the functionality are assumed to not support backing files, 3712 * hence all their sectors are reported as allocated. 3713 * 3714 * If 'sector_num' is beyond the end of the disk image the return value is 0 3715 * and 'pnum' is set to 0. 3716 * 3717 * 'pnum' is set to the number of sectors (including and immediately following 3718 * the specified sector) that are known to be in the same 3719 * allocated/unallocated state. 3720 * 3721 * 'nb_sectors' is the max value 'pnum' should be set to. If nb_sectors goes 3722 * beyond the end of the disk image it will be clamped. 3723 */ 3724 static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, 3725 int64_t sector_num, 3726 int nb_sectors, int *pnum) 3727 { 3728 int64_t length; 3729 int64_t n; 3730 int64_t ret, ret2; 3731 3732 length = bdrv_getlength(bs); 3733 if (length < 0) { 3734 return length; 3735 } 3736 3737 if (sector_num >= (length >> BDRV_SECTOR_BITS)) { 3738 *pnum = 0; 3739 return 0; 3740 } 3741 3742 n = bs->total_sectors - sector_num; 3743 if (n < nb_sectors) { 3744 nb_sectors = n; 3745 } 3746 3747 if (!bs->drv->bdrv_co_get_block_status) { 3748 *pnum = nb_sectors; 3749 ret = BDRV_BLOCK_DATA; 3750 if (bs->drv->protocol_name) { 3751 ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE); 3752 } 3753 return ret; 3754 } 3755 3756 ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum); 3757 if (ret < 0) { 3758 *pnum = 0; 3759 return ret; 3760 } 3761 3762 if (ret & BDRV_BLOCK_RAW) { 3763 assert(ret & BDRV_BLOCK_OFFSET_VALID); 3764 return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3765 *pnum, pnum); 3766 } 3767 3768 if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) { 3769 if (bdrv_unallocated_blocks_are_zero(bs)) { 3770 ret |= BDRV_BLOCK_ZERO; 3771 } else if (bs->backing_hd) { 3772 BlockDriverState *bs2 = bs->backing_hd; 3773 int64_t length2 = bdrv_getlength(bs2); 3774 if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) { 3775 ret |= BDRV_BLOCK_ZERO; 3776 } 3777 } 3778 } 3779 3780 if (bs->file && 3781 (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) && 3782 (ret & BDRV_BLOCK_OFFSET_VALID)) { 3783 ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS, 3784 *pnum, pnum); 3785 if (ret2 >= 0) { 3786 /* Ignore errors. This is just providing extra information, it 3787 * is useful but not necessary. 3788 */ 3789 ret |= (ret2 & BDRV_BLOCK_ZERO); 3790 } 3791 } 3792 3793 return ret; 3794 } 3795 3796 /* Coroutine wrapper for bdrv_get_block_status() */ 3797 static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque) 3798 { 3799 BdrvCoGetBlockStatusData *data = opaque; 3800 BlockDriverState *bs = data->bs; 3801 3802 data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors, 3803 data->pnum); 3804 data->done = true; 3805 } 3806 3807 /* 3808 * Synchronous wrapper around bdrv_co_get_block_status(). 3809 * 3810 * See bdrv_co_get_block_status() for details. 3811 */ 3812 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num, 3813 int nb_sectors, int *pnum) 3814 { 3815 Coroutine *co; 3816 BdrvCoGetBlockStatusData data = { 3817 .bs = bs, 3818 .sector_num = sector_num, 3819 .nb_sectors = nb_sectors, 3820 .pnum = pnum, 3821 .done = false, 3822 }; 3823 3824 if (qemu_in_coroutine()) { 3825 /* Fast-path if already in coroutine context */ 3826 bdrv_get_block_status_co_entry(&data); 3827 } else { 3828 co = qemu_coroutine_create(bdrv_get_block_status_co_entry); 3829 qemu_coroutine_enter(co, &data); 3830 while (!data.done) { 3831 qemu_aio_wait(); 3832 } 3833 } 3834 return data.ret; 3835 } 3836 3837 int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, 3838 int nb_sectors, int *pnum) 3839 { 3840 int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum); 3841 if (ret < 0) { 3842 return ret; 3843 } 3844 return 3845 (ret & BDRV_BLOCK_DATA) || 3846 ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs)); 3847 } 3848 3849 /* 3850 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP] 3851 * 3852 * Return true if the given sector is allocated in any image between 3853 * BASE and TOP (inclusive). BASE can be NULL to check if the given 3854 * sector is allocated in any image of the chain. Return false otherwise. 3855 * 3856 * 'pnum' is set to the number of sectors (including and immediately following 3857 * the specified sector) that are known to be in the same 3858 * allocated/unallocated state. 3859 * 3860 */ 3861 int bdrv_is_allocated_above(BlockDriverState *top, 3862 BlockDriverState *base, 3863 int64_t sector_num, 3864 int nb_sectors, int *pnum) 3865 { 3866 BlockDriverState *intermediate; 3867 int ret, n = nb_sectors; 3868 3869 intermediate = top; 3870 while (intermediate && intermediate != base) { 3871 int pnum_inter; 3872 ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors, 3873 &pnum_inter); 3874 if (ret < 0) { 3875 return ret; 3876 } else if (ret) { 3877 *pnum = pnum_inter; 3878 return 1; 3879 } 3880 3881 /* 3882 * [sector_num, nb_sectors] is unallocated on top but intermediate 3883 * might have 3884 * 3885 * [sector_num+x, nr_sectors] allocated. 3886 */ 3887 if (n > pnum_inter && 3888 (intermediate == top || 3889 sector_num + pnum_inter < intermediate->total_sectors)) { 3890 n = pnum_inter; 3891 } 3892 3893 intermediate = intermediate->backing_hd; 3894 } 3895 3896 *pnum = n; 3897 return 0; 3898 } 3899 3900 const char *bdrv_get_encrypted_filename(BlockDriverState *bs) 3901 { 3902 if (bs->backing_hd && bs->backing_hd->encrypted) 3903 return bs->backing_file; 3904 else if (bs->encrypted) 3905 return bs->filename; 3906 else 3907 return NULL; 3908 } 3909 3910 void bdrv_get_backing_filename(BlockDriverState *bs, 3911 char *filename, int filename_size) 3912 { 3913 pstrcpy(filename, filename_size, bs->backing_file); 3914 } 3915 3916 int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num, 3917 const uint8_t *buf, int nb_sectors) 3918 { 3919 BlockDriver *drv = bs->drv; 3920 if (!drv) 3921 return -ENOMEDIUM; 3922 if (!drv->bdrv_write_compressed) 3923 return -ENOTSUP; 3924 if (bdrv_check_request(bs, sector_num, nb_sectors)) 3925 return -EIO; 3926 3927 assert(QLIST_EMPTY(&bs->dirty_bitmaps)); 3928 3929 return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors); 3930 } 3931 3932 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 3933 { 3934 BlockDriver *drv = bs->drv; 3935 if (!drv) 3936 return -ENOMEDIUM; 3937 if (!drv->bdrv_get_info) 3938 return -ENOTSUP; 3939 memset(bdi, 0, sizeof(*bdi)); 3940 return drv->bdrv_get_info(bs, bdi); 3941 } 3942 3943 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs) 3944 { 3945 BlockDriver *drv = bs->drv; 3946 if (drv && drv->bdrv_get_specific_info) { 3947 return drv->bdrv_get_specific_info(bs); 3948 } 3949 return NULL; 3950 } 3951 3952 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, 3953 int64_t pos, int size) 3954 { 3955 QEMUIOVector qiov; 3956 struct iovec iov = { 3957 .iov_base = (void *) buf, 3958 .iov_len = size, 3959 }; 3960 3961 qemu_iovec_init_external(&qiov, &iov, 1); 3962 return bdrv_writev_vmstate(bs, &qiov, pos); 3963 } 3964 3965 int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos) 3966 { 3967 BlockDriver *drv = bs->drv; 3968 3969 if (!drv) { 3970 return -ENOMEDIUM; 3971 } else if (drv->bdrv_save_vmstate) { 3972 return drv->bdrv_save_vmstate(bs, qiov, pos); 3973 } else if (bs->file) { 3974 return bdrv_writev_vmstate(bs->file, qiov, pos); 3975 } 3976 3977 return -ENOTSUP; 3978 } 3979 3980 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf, 3981 int64_t pos, int size) 3982 { 3983 BlockDriver *drv = bs->drv; 3984 if (!drv) 3985 return -ENOMEDIUM; 3986 if (drv->bdrv_load_vmstate) 3987 return drv->bdrv_load_vmstate(bs, buf, pos, size); 3988 if (bs->file) 3989 return bdrv_load_vmstate(bs->file, buf, pos, size); 3990 return -ENOTSUP; 3991 } 3992 3993 void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event) 3994 { 3995 if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) { 3996 return; 3997 } 3998 3999 bs->drv->bdrv_debug_event(bs, event); 4000 } 4001 4002 int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event, 4003 const char *tag) 4004 { 4005 while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) { 4006 bs = bs->file; 4007 } 4008 4009 if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) { 4010 return bs->drv->bdrv_debug_breakpoint(bs, event, tag); 4011 } 4012 4013 return -ENOTSUP; 4014 } 4015 4016 int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag) 4017 { 4018 while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) { 4019 bs = bs->file; 4020 } 4021 4022 if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) { 4023 return bs->drv->bdrv_debug_remove_breakpoint(bs, tag); 4024 } 4025 4026 return -ENOTSUP; 4027 } 4028 4029 int bdrv_debug_resume(BlockDriverState *bs, const char *tag) 4030 { 4031 while (bs && bs->drv && !bs->drv->bdrv_debug_resume) { 4032 bs = bs->file; 4033 } 4034 4035 if (bs && bs->drv && bs->drv->bdrv_debug_resume) { 4036 return bs->drv->bdrv_debug_resume(bs, tag); 4037 } 4038 4039 return -ENOTSUP; 4040 } 4041 4042 bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag) 4043 { 4044 while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) { 4045 bs = bs->file; 4046 } 4047 4048 if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) { 4049 return bs->drv->bdrv_debug_is_suspended(bs, tag); 4050 } 4051 4052 return false; 4053 } 4054 4055 int bdrv_is_snapshot(BlockDriverState *bs) 4056 { 4057 return !!(bs->open_flags & BDRV_O_SNAPSHOT); 4058 } 4059 4060 /* backing_file can either be relative, or absolute, or a protocol. If it is 4061 * relative, it must be relative to the chain. So, passing in bs->filename 4062 * from a BDS as backing_file should not be done, as that may be relative to 4063 * the CWD rather than the chain. */ 4064 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, 4065 const char *backing_file) 4066 { 4067 char *filename_full = NULL; 4068 char *backing_file_full = NULL; 4069 char *filename_tmp = NULL; 4070 int is_protocol = 0; 4071 BlockDriverState *curr_bs = NULL; 4072 BlockDriverState *retval = NULL; 4073 4074 if (!bs || !bs->drv || !backing_file) { 4075 return NULL; 4076 } 4077 4078 filename_full = g_malloc(PATH_MAX); 4079 backing_file_full = g_malloc(PATH_MAX); 4080 filename_tmp = g_malloc(PATH_MAX); 4081 4082 is_protocol = path_has_protocol(backing_file); 4083 4084 for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) { 4085 4086 /* If either of the filename paths is actually a protocol, then 4087 * compare unmodified paths; otherwise make paths relative */ 4088 if (is_protocol || path_has_protocol(curr_bs->backing_file)) { 4089 if (strcmp(backing_file, curr_bs->backing_file) == 0) { 4090 retval = curr_bs->backing_hd; 4091 break; 4092 } 4093 } else { 4094 /* If not an absolute filename path, make it relative to the current 4095 * image's filename path */ 4096 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 4097 backing_file); 4098 4099 /* We are going to compare absolute pathnames */ 4100 if (!realpath(filename_tmp, filename_full)) { 4101 continue; 4102 } 4103 4104 /* We need to make sure the backing filename we are comparing against 4105 * is relative to the current image filename (or absolute) */ 4106 path_combine(filename_tmp, PATH_MAX, curr_bs->filename, 4107 curr_bs->backing_file); 4108 4109 if (!realpath(filename_tmp, backing_file_full)) { 4110 continue; 4111 } 4112 4113 if (strcmp(backing_file_full, filename_full) == 0) { 4114 retval = curr_bs->backing_hd; 4115 break; 4116 } 4117 } 4118 } 4119 4120 g_free(filename_full); 4121 g_free(backing_file_full); 4122 g_free(filename_tmp); 4123 return retval; 4124 } 4125 4126 int bdrv_get_backing_file_depth(BlockDriverState *bs) 4127 { 4128 if (!bs->drv) { 4129 return 0; 4130 } 4131 4132 if (!bs->backing_hd) { 4133 return 0; 4134 } 4135 4136 return 1 + bdrv_get_backing_file_depth(bs->backing_hd); 4137 } 4138 4139 BlockDriverState *bdrv_find_base(BlockDriverState *bs) 4140 { 4141 BlockDriverState *curr_bs = NULL; 4142 4143 if (!bs) { 4144 return NULL; 4145 } 4146 4147 curr_bs = bs; 4148 4149 while (curr_bs->backing_hd) { 4150 curr_bs = curr_bs->backing_hd; 4151 } 4152 return curr_bs; 4153 } 4154 4155 /**************************************************************/ 4156 /* async I/Os */ 4157 4158 BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, 4159 QEMUIOVector *qiov, int nb_sectors, 4160 BlockDriverCompletionFunc *cb, void *opaque) 4161 { 4162 trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); 4163 4164 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 4165 cb, opaque, false); 4166 } 4167 4168 BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, 4169 QEMUIOVector *qiov, int nb_sectors, 4170 BlockDriverCompletionFunc *cb, void *opaque) 4171 { 4172 trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); 4173 4174 return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0, 4175 cb, opaque, true); 4176 } 4177 4178 BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs, 4179 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags, 4180 BlockDriverCompletionFunc *cb, void *opaque) 4181 { 4182 trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque); 4183 4184 return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors, 4185 BDRV_REQ_ZERO_WRITE | flags, 4186 cb, opaque, true); 4187 } 4188 4189 4190 typedef struct MultiwriteCB { 4191 int error; 4192 int num_requests; 4193 int num_callbacks; 4194 struct { 4195 BlockDriverCompletionFunc *cb; 4196 void *opaque; 4197 QEMUIOVector *free_qiov; 4198 } callbacks[]; 4199 } MultiwriteCB; 4200 4201 static void multiwrite_user_cb(MultiwriteCB *mcb) 4202 { 4203 int i; 4204 4205 for (i = 0; i < mcb->num_callbacks; i++) { 4206 mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error); 4207 if (mcb->callbacks[i].free_qiov) { 4208 qemu_iovec_destroy(mcb->callbacks[i].free_qiov); 4209 } 4210 g_free(mcb->callbacks[i].free_qiov); 4211 } 4212 } 4213 4214 static void multiwrite_cb(void *opaque, int ret) 4215 { 4216 MultiwriteCB *mcb = opaque; 4217 4218 trace_multiwrite_cb(mcb, ret); 4219 4220 if (ret < 0 && !mcb->error) { 4221 mcb->error = ret; 4222 } 4223 4224 mcb->num_requests--; 4225 if (mcb->num_requests == 0) { 4226 multiwrite_user_cb(mcb); 4227 g_free(mcb); 4228 } 4229 } 4230 4231 static int multiwrite_req_compare(const void *a, const void *b) 4232 { 4233 const BlockRequest *req1 = a, *req2 = b; 4234 4235 /* 4236 * Note that we can't simply subtract req2->sector from req1->sector 4237 * here as that could overflow the return value. 4238 */ 4239 if (req1->sector > req2->sector) { 4240 return 1; 4241 } else if (req1->sector < req2->sector) { 4242 return -1; 4243 } else { 4244 return 0; 4245 } 4246 } 4247 4248 /* 4249 * Takes a bunch of requests and tries to merge them. Returns the number of 4250 * requests that remain after merging. 4251 */ 4252 static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs, 4253 int num_reqs, MultiwriteCB *mcb) 4254 { 4255 int i, outidx; 4256 4257 // Sort requests by start sector 4258 qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare); 4259 4260 // Check if adjacent requests touch the same clusters. If so, combine them, 4261 // filling up gaps with zero sectors. 4262 outidx = 0; 4263 for (i = 1; i < num_reqs; i++) { 4264 int merge = 0; 4265 int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors; 4266 4267 // Handle exactly sequential writes and overlapping writes. 4268 if (reqs[i].sector <= oldreq_last) { 4269 merge = 1; 4270 } 4271 4272 if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) { 4273 merge = 0; 4274 } 4275 4276 if (merge) { 4277 size_t size; 4278 QEMUIOVector *qiov = g_malloc0(sizeof(*qiov)); 4279 qemu_iovec_init(qiov, 4280 reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1); 4281 4282 // Add the first request to the merged one. If the requests are 4283 // overlapping, drop the last sectors of the first request. 4284 size = (reqs[i].sector - reqs[outidx].sector) << 9; 4285 qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size); 4286 4287 // We should need to add any zeros between the two requests 4288 assert (reqs[i].sector <= oldreq_last); 4289 4290 // Add the second request 4291 qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size); 4292 4293 reqs[outidx].nb_sectors = qiov->size >> 9; 4294 reqs[outidx].qiov = qiov; 4295 4296 mcb->callbacks[i].free_qiov = reqs[outidx].qiov; 4297 } else { 4298 outidx++; 4299 reqs[outidx].sector = reqs[i].sector; 4300 reqs[outidx].nb_sectors = reqs[i].nb_sectors; 4301 reqs[outidx].qiov = reqs[i].qiov; 4302 } 4303 } 4304 4305 return outidx + 1; 4306 } 4307 4308 /* 4309 * Submit multiple AIO write requests at once. 4310 * 4311 * On success, the function returns 0 and all requests in the reqs array have 4312 * been submitted. In error case this function returns -1, and any of the 4313 * requests may or may not be submitted yet. In particular, this means that the 4314 * callback will be called for some of the requests, for others it won't. The 4315 * caller must check the error field of the BlockRequest to wait for the right 4316 * callbacks (if error != 0, no callback will be called). 4317 * 4318 * The implementation may modify the contents of the reqs array, e.g. to merge 4319 * requests. However, the fields opaque and error are left unmodified as they 4320 * are used to signal failure for a single request to the caller. 4321 */ 4322 int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs) 4323 { 4324 MultiwriteCB *mcb; 4325 int i; 4326 4327 /* don't submit writes if we don't have a medium */ 4328 if (bs->drv == NULL) { 4329 for (i = 0; i < num_reqs; i++) { 4330 reqs[i].error = -ENOMEDIUM; 4331 } 4332 return -1; 4333 } 4334 4335 if (num_reqs == 0) { 4336 return 0; 4337 } 4338 4339 // Create MultiwriteCB structure 4340 mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks)); 4341 mcb->num_requests = 0; 4342 mcb->num_callbacks = num_reqs; 4343 4344 for (i = 0; i < num_reqs; i++) { 4345 mcb->callbacks[i].cb = reqs[i].cb; 4346 mcb->callbacks[i].opaque = reqs[i].opaque; 4347 } 4348 4349 // Check for mergable requests 4350 num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb); 4351 4352 trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs); 4353 4354 /* Run the aio requests. */ 4355 mcb->num_requests = num_reqs; 4356 for (i = 0; i < num_reqs; i++) { 4357 bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov, 4358 reqs[i].nb_sectors, reqs[i].flags, 4359 multiwrite_cb, mcb, 4360 true); 4361 } 4362 4363 return 0; 4364 } 4365 4366 void bdrv_aio_cancel(BlockDriverAIOCB *acb) 4367 { 4368 acb->aiocb_info->cancel(acb); 4369 } 4370 4371 /**************************************************************/ 4372 /* async block device emulation */ 4373 4374 typedef struct BlockDriverAIOCBSync { 4375 BlockDriverAIOCB common; 4376 QEMUBH *bh; 4377 int ret; 4378 /* vector translation state */ 4379 QEMUIOVector *qiov; 4380 uint8_t *bounce; 4381 int is_write; 4382 } BlockDriverAIOCBSync; 4383 4384 static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb) 4385 { 4386 BlockDriverAIOCBSync *acb = 4387 container_of(blockacb, BlockDriverAIOCBSync, common); 4388 qemu_bh_delete(acb->bh); 4389 acb->bh = NULL; 4390 qemu_aio_release(acb); 4391 } 4392 4393 static const AIOCBInfo bdrv_em_aiocb_info = { 4394 .aiocb_size = sizeof(BlockDriverAIOCBSync), 4395 .cancel = bdrv_aio_cancel_em, 4396 }; 4397 4398 static void bdrv_aio_bh_cb(void *opaque) 4399 { 4400 BlockDriverAIOCBSync *acb = opaque; 4401 4402 if (!acb->is_write) 4403 qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size); 4404 qemu_vfree(acb->bounce); 4405 acb->common.cb(acb->common.opaque, acb->ret); 4406 qemu_bh_delete(acb->bh); 4407 acb->bh = NULL; 4408 qemu_aio_release(acb); 4409 } 4410 4411 static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs, 4412 int64_t sector_num, 4413 QEMUIOVector *qiov, 4414 int nb_sectors, 4415 BlockDriverCompletionFunc *cb, 4416 void *opaque, 4417 int is_write) 4418 4419 { 4420 BlockDriverAIOCBSync *acb; 4421 4422 acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque); 4423 acb->is_write = is_write; 4424 acb->qiov = qiov; 4425 acb->bounce = qemu_blockalign(bs, qiov->size); 4426 acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb); 4427 4428 if (is_write) { 4429 qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); 4430 acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors); 4431 } else { 4432 acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors); 4433 } 4434 4435 qemu_bh_schedule(acb->bh); 4436 4437 return &acb->common; 4438 } 4439 4440 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs, 4441 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 4442 BlockDriverCompletionFunc *cb, void *opaque) 4443 { 4444 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 4445 } 4446 4447 static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs, 4448 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 4449 BlockDriverCompletionFunc *cb, void *opaque) 4450 { 4451 return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); 4452 } 4453 4454 4455 typedef struct BlockDriverAIOCBCoroutine { 4456 BlockDriverAIOCB common; 4457 BlockRequest req; 4458 bool is_write; 4459 bool *done; 4460 QEMUBH* bh; 4461 } BlockDriverAIOCBCoroutine; 4462 4463 static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb) 4464 { 4465 BlockDriverAIOCBCoroutine *acb = 4466 container_of(blockacb, BlockDriverAIOCBCoroutine, common); 4467 bool done = false; 4468 4469 acb->done = &done; 4470 while (!done) { 4471 qemu_aio_wait(); 4472 } 4473 } 4474 4475 static const AIOCBInfo bdrv_em_co_aiocb_info = { 4476 .aiocb_size = sizeof(BlockDriverAIOCBCoroutine), 4477 .cancel = bdrv_aio_co_cancel_em, 4478 }; 4479 4480 static void bdrv_co_em_bh(void *opaque) 4481 { 4482 BlockDriverAIOCBCoroutine *acb = opaque; 4483 4484 acb->common.cb(acb->common.opaque, acb->req.error); 4485 4486 if (acb->done) { 4487 *acb->done = true; 4488 } 4489 4490 qemu_bh_delete(acb->bh); 4491 qemu_aio_release(acb); 4492 } 4493 4494 /* Invoke bdrv_co_do_readv/bdrv_co_do_writev */ 4495 static void coroutine_fn bdrv_co_do_rw(void *opaque) 4496 { 4497 BlockDriverAIOCBCoroutine *acb = opaque; 4498 BlockDriverState *bs = acb->common.bs; 4499 4500 if (!acb->is_write) { 4501 acb->req.error = bdrv_co_do_readv(bs, acb->req.sector, 4502 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4503 } else { 4504 acb->req.error = bdrv_co_do_writev(bs, acb->req.sector, 4505 acb->req.nb_sectors, acb->req.qiov, acb->req.flags); 4506 } 4507 4508 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4509 qemu_bh_schedule(acb->bh); 4510 } 4511 4512 static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs, 4513 int64_t sector_num, 4514 QEMUIOVector *qiov, 4515 int nb_sectors, 4516 BdrvRequestFlags flags, 4517 BlockDriverCompletionFunc *cb, 4518 void *opaque, 4519 bool is_write) 4520 { 4521 Coroutine *co; 4522 BlockDriverAIOCBCoroutine *acb; 4523 4524 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4525 acb->req.sector = sector_num; 4526 acb->req.nb_sectors = nb_sectors; 4527 acb->req.qiov = qiov; 4528 acb->req.flags = flags; 4529 acb->is_write = is_write; 4530 acb->done = NULL; 4531 4532 co = qemu_coroutine_create(bdrv_co_do_rw); 4533 qemu_coroutine_enter(co, acb); 4534 4535 return &acb->common; 4536 } 4537 4538 static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque) 4539 { 4540 BlockDriverAIOCBCoroutine *acb = opaque; 4541 BlockDriverState *bs = acb->common.bs; 4542 4543 acb->req.error = bdrv_co_flush(bs); 4544 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4545 qemu_bh_schedule(acb->bh); 4546 } 4547 4548 BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, 4549 BlockDriverCompletionFunc *cb, void *opaque) 4550 { 4551 trace_bdrv_aio_flush(bs, opaque); 4552 4553 Coroutine *co; 4554 BlockDriverAIOCBCoroutine *acb; 4555 4556 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4557 acb->done = NULL; 4558 4559 co = qemu_coroutine_create(bdrv_aio_flush_co_entry); 4560 qemu_coroutine_enter(co, acb); 4561 4562 return &acb->common; 4563 } 4564 4565 static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque) 4566 { 4567 BlockDriverAIOCBCoroutine *acb = opaque; 4568 BlockDriverState *bs = acb->common.bs; 4569 4570 acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors); 4571 acb->bh = qemu_bh_new(bdrv_co_em_bh, acb); 4572 qemu_bh_schedule(acb->bh); 4573 } 4574 4575 BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs, 4576 int64_t sector_num, int nb_sectors, 4577 BlockDriverCompletionFunc *cb, void *opaque) 4578 { 4579 Coroutine *co; 4580 BlockDriverAIOCBCoroutine *acb; 4581 4582 trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque); 4583 4584 acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque); 4585 acb->req.sector = sector_num; 4586 acb->req.nb_sectors = nb_sectors; 4587 acb->done = NULL; 4588 co = qemu_coroutine_create(bdrv_aio_discard_co_entry); 4589 qemu_coroutine_enter(co, acb); 4590 4591 return &acb->common; 4592 } 4593 4594 void bdrv_init(void) 4595 { 4596 module_call_init(MODULE_INIT_BLOCK); 4597 } 4598 4599 void bdrv_init_with_whitelist(void) 4600 { 4601 use_bdrv_whitelist = 1; 4602 bdrv_init(); 4603 } 4604 4605 void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs, 4606 BlockDriverCompletionFunc *cb, void *opaque) 4607 { 4608 BlockDriverAIOCB *acb; 4609 4610 acb = g_slice_alloc(aiocb_info->aiocb_size); 4611 acb->aiocb_info = aiocb_info; 4612 acb->bs = bs; 4613 acb->cb = cb; 4614 acb->opaque = opaque; 4615 return acb; 4616 } 4617 4618 void qemu_aio_release(void *p) 4619 { 4620 BlockDriverAIOCB *acb = p; 4621 g_slice_free1(acb->aiocb_info->aiocb_size, acb); 4622 } 4623 4624 /**************************************************************/ 4625 /* Coroutine block device emulation */ 4626 4627 typedef struct CoroutineIOCompletion { 4628 Coroutine *coroutine; 4629 int ret; 4630 } CoroutineIOCompletion; 4631 4632 static void bdrv_co_io_em_complete(void *opaque, int ret) 4633 { 4634 CoroutineIOCompletion *co = opaque; 4635 4636 co->ret = ret; 4637 qemu_coroutine_enter(co->coroutine, NULL); 4638 } 4639 4640 static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num, 4641 int nb_sectors, QEMUIOVector *iov, 4642 bool is_write) 4643 { 4644 CoroutineIOCompletion co = { 4645 .coroutine = qemu_coroutine_self(), 4646 }; 4647 BlockDriverAIOCB *acb; 4648 4649 if (is_write) { 4650 acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors, 4651 bdrv_co_io_em_complete, &co); 4652 } else { 4653 acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors, 4654 bdrv_co_io_em_complete, &co); 4655 } 4656 4657 trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb); 4658 if (!acb) { 4659 return -EIO; 4660 } 4661 qemu_coroutine_yield(); 4662 4663 return co.ret; 4664 } 4665 4666 static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs, 4667 int64_t sector_num, int nb_sectors, 4668 QEMUIOVector *iov) 4669 { 4670 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false); 4671 } 4672 4673 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, 4674 int64_t sector_num, int nb_sectors, 4675 QEMUIOVector *iov) 4676 { 4677 return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true); 4678 } 4679 4680 static void coroutine_fn bdrv_flush_co_entry(void *opaque) 4681 { 4682 RwCo *rwco = opaque; 4683 4684 rwco->ret = bdrv_co_flush(rwco->bs); 4685 } 4686 4687 int coroutine_fn bdrv_co_flush(BlockDriverState *bs) 4688 { 4689 int ret; 4690 4691 if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { 4692 return 0; 4693 } 4694 4695 /* Write back cached data to the OS even with cache=unsafe */ 4696 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); 4697 if (bs->drv->bdrv_co_flush_to_os) { 4698 ret = bs->drv->bdrv_co_flush_to_os(bs); 4699 if (ret < 0) { 4700 return ret; 4701 } 4702 } 4703 4704 /* But don't actually force it to the disk with cache=unsafe */ 4705 if (bs->open_flags & BDRV_O_NO_FLUSH) { 4706 goto flush_parent; 4707 } 4708 4709 BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK); 4710 if (bs->drv->bdrv_co_flush_to_disk) { 4711 ret = bs->drv->bdrv_co_flush_to_disk(bs); 4712 } else if (bs->drv->bdrv_aio_flush) { 4713 BlockDriverAIOCB *acb; 4714 CoroutineIOCompletion co = { 4715 .coroutine = qemu_coroutine_self(), 4716 }; 4717 4718 acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co); 4719 if (acb == NULL) { 4720 ret = -EIO; 4721 } else { 4722 qemu_coroutine_yield(); 4723 ret = co.ret; 4724 } 4725 } else { 4726 /* 4727 * Some block drivers always operate in either writethrough or unsafe 4728 * mode and don't support bdrv_flush therefore. Usually qemu doesn't 4729 * know how the server works (because the behaviour is hardcoded or 4730 * depends on server-side configuration), so we can't ensure that 4731 * everything is safe on disk. Returning an error doesn't work because 4732 * that would break guests even if the server operates in writethrough 4733 * mode. 4734 * 4735 * Let's hope the user knows what he's doing. 4736 */ 4737 ret = 0; 4738 } 4739 if (ret < 0) { 4740 return ret; 4741 } 4742 4743 /* Now flush the underlying protocol. It will also have BDRV_O_NO_FLUSH 4744 * in the case of cache=unsafe, so there are no useless flushes. 4745 */ 4746 flush_parent: 4747 return bdrv_co_flush(bs->file); 4748 } 4749 4750 void bdrv_invalidate_cache(BlockDriverState *bs) 4751 { 4752 if (bs->drv && bs->drv->bdrv_invalidate_cache) { 4753 bs->drv->bdrv_invalidate_cache(bs); 4754 } 4755 } 4756 4757 void bdrv_invalidate_cache_all(void) 4758 { 4759 BlockDriverState *bs; 4760 4761 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 4762 bdrv_invalidate_cache(bs); 4763 } 4764 } 4765 4766 void bdrv_clear_incoming_migration_all(void) 4767 { 4768 BlockDriverState *bs; 4769 4770 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 4771 bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING); 4772 } 4773 } 4774 4775 int bdrv_flush(BlockDriverState *bs) 4776 { 4777 Coroutine *co; 4778 RwCo rwco = { 4779 .bs = bs, 4780 .ret = NOT_DONE, 4781 }; 4782 4783 if (qemu_in_coroutine()) { 4784 /* Fast-path if already in coroutine context */ 4785 bdrv_flush_co_entry(&rwco); 4786 } else { 4787 co = qemu_coroutine_create(bdrv_flush_co_entry); 4788 qemu_coroutine_enter(co, &rwco); 4789 while (rwco.ret == NOT_DONE) { 4790 qemu_aio_wait(); 4791 } 4792 } 4793 4794 return rwco.ret; 4795 } 4796 4797 typedef struct DiscardCo { 4798 BlockDriverState *bs; 4799 int64_t sector_num; 4800 int nb_sectors; 4801 int ret; 4802 } DiscardCo; 4803 static void coroutine_fn bdrv_discard_co_entry(void *opaque) 4804 { 4805 DiscardCo *rwco = opaque; 4806 4807 rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors); 4808 } 4809 4810 /* if no limit is specified in the BlockLimits use a default 4811 * of 32768 512-byte sectors (16 MiB) per request. 4812 */ 4813 #define MAX_DISCARD_DEFAULT 32768 4814 4815 int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, 4816 int nb_sectors) 4817 { 4818 int max_discard; 4819 4820 if (!bs->drv) { 4821 return -ENOMEDIUM; 4822 } else if (bdrv_check_request(bs, sector_num, nb_sectors)) { 4823 return -EIO; 4824 } else if (bs->read_only) { 4825 return -EROFS; 4826 } 4827 4828 bdrv_reset_dirty(bs, sector_num, nb_sectors); 4829 4830 /* Do nothing if disabled. */ 4831 if (!(bs->open_flags & BDRV_O_UNMAP)) { 4832 return 0; 4833 } 4834 4835 if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) { 4836 return 0; 4837 } 4838 4839 max_discard = bs->bl.max_discard ? bs->bl.max_discard : MAX_DISCARD_DEFAULT; 4840 while (nb_sectors > 0) { 4841 int ret; 4842 int num = nb_sectors; 4843 4844 /* align request */ 4845 if (bs->bl.discard_alignment && 4846 num >= bs->bl.discard_alignment && 4847 sector_num % bs->bl.discard_alignment) { 4848 if (num > bs->bl.discard_alignment) { 4849 num = bs->bl.discard_alignment; 4850 } 4851 num -= sector_num % bs->bl.discard_alignment; 4852 } 4853 4854 /* limit request size */ 4855 if (num > max_discard) { 4856 num = max_discard; 4857 } 4858 4859 if (bs->drv->bdrv_co_discard) { 4860 ret = bs->drv->bdrv_co_discard(bs, sector_num, num); 4861 } else { 4862 BlockDriverAIOCB *acb; 4863 CoroutineIOCompletion co = { 4864 .coroutine = qemu_coroutine_self(), 4865 }; 4866 4867 acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors, 4868 bdrv_co_io_em_complete, &co); 4869 if (acb == NULL) { 4870 return -EIO; 4871 } else { 4872 qemu_coroutine_yield(); 4873 ret = co.ret; 4874 } 4875 } 4876 if (ret && ret != -ENOTSUP) { 4877 return ret; 4878 } 4879 4880 sector_num += num; 4881 nb_sectors -= num; 4882 } 4883 return 0; 4884 } 4885 4886 int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors) 4887 { 4888 Coroutine *co; 4889 DiscardCo rwco = { 4890 .bs = bs, 4891 .sector_num = sector_num, 4892 .nb_sectors = nb_sectors, 4893 .ret = NOT_DONE, 4894 }; 4895 4896 if (qemu_in_coroutine()) { 4897 /* Fast-path if already in coroutine context */ 4898 bdrv_discard_co_entry(&rwco); 4899 } else { 4900 co = qemu_coroutine_create(bdrv_discard_co_entry); 4901 qemu_coroutine_enter(co, &rwco); 4902 while (rwco.ret == NOT_DONE) { 4903 qemu_aio_wait(); 4904 } 4905 } 4906 4907 return rwco.ret; 4908 } 4909 4910 /**************************************************************/ 4911 /* removable device support */ 4912 4913 /** 4914 * Return TRUE if the media is present 4915 */ 4916 int bdrv_is_inserted(BlockDriverState *bs) 4917 { 4918 BlockDriver *drv = bs->drv; 4919 4920 if (!drv) 4921 return 0; 4922 if (!drv->bdrv_is_inserted) 4923 return 1; 4924 return drv->bdrv_is_inserted(bs); 4925 } 4926 4927 /** 4928 * Return whether the media changed since the last call to this 4929 * function, or -ENOTSUP if we don't know. Most drivers don't know. 4930 */ 4931 int bdrv_media_changed(BlockDriverState *bs) 4932 { 4933 BlockDriver *drv = bs->drv; 4934 4935 if (drv && drv->bdrv_media_changed) { 4936 return drv->bdrv_media_changed(bs); 4937 } 4938 return -ENOTSUP; 4939 } 4940 4941 /** 4942 * If eject_flag is TRUE, eject the media. Otherwise, close the tray 4943 */ 4944 void bdrv_eject(BlockDriverState *bs, bool eject_flag) 4945 { 4946 BlockDriver *drv = bs->drv; 4947 4948 if (drv && drv->bdrv_eject) { 4949 drv->bdrv_eject(bs, eject_flag); 4950 } 4951 4952 if (bs->device_name[0] != '\0') { 4953 bdrv_emit_qmp_eject_event(bs, eject_flag); 4954 } 4955 } 4956 4957 /** 4958 * Lock or unlock the media (if it is locked, the user won't be able 4959 * to eject it manually). 4960 */ 4961 void bdrv_lock_medium(BlockDriverState *bs, bool locked) 4962 { 4963 BlockDriver *drv = bs->drv; 4964 4965 trace_bdrv_lock_medium(bs, locked); 4966 4967 if (drv && drv->bdrv_lock_medium) { 4968 drv->bdrv_lock_medium(bs, locked); 4969 } 4970 } 4971 4972 /* needed for generic scsi interface */ 4973 4974 int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf) 4975 { 4976 BlockDriver *drv = bs->drv; 4977 4978 if (drv && drv->bdrv_ioctl) 4979 return drv->bdrv_ioctl(bs, req, buf); 4980 return -ENOTSUP; 4981 } 4982 4983 BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, 4984 unsigned long int req, void *buf, 4985 BlockDriverCompletionFunc *cb, void *opaque) 4986 { 4987 BlockDriver *drv = bs->drv; 4988 4989 if (drv && drv->bdrv_aio_ioctl) 4990 return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque); 4991 return NULL; 4992 } 4993 4994 void bdrv_set_guest_block_size(BlockDriverState *bs, int align) 4995 { 4996 bs->guest_block_size = align; 4997 } 4998 4999 void *qemu_blockalign(BlockDriverState *bs, size_t size) 5000 { 5001 return qemu_memalign(bdrv_opt_mem_align(bs), size); 5002 } 5003 5004 /* 5005 * Check if all memory in this vector is sector aligned. 5006 */ 5007 bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov) 5008 { 5009 int i; 5010 size_t alignment = bdrv_opt_mem_align(bs); 5011 5012 for (i = 0; i < qiov->niov; i++) { 5013 if ((uintptr_t) qiov->iov[i].iov_base % alignment) { 5014 return false; 5015 } 5016 if (qiov->iov[i].iov_len % alignment) { 5017 return false; 5018 } 5019 } 5020 5021 return true; 5022 } 5023 5024 BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity) 5025 { 5026 int64_t bitmap_size; 5027 BdrvDirtyBitmap *bitmap; 5028 5029 assert((granularity & (granularity - 1)) == 0); 5030 5031 granularity >>= BDRV_SECTOR_BITS; 5032 assert(granularity); 5033 bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS); 5034 bitmap = g_malloc0(sizeof(BdrvDirtyBitmap)); 5035 bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1); 5036 QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list); 5037 return bitmap; 5038 } 5039 5040 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 5041 { 5042 BdrvDirtyBitmap *bm, *next; 5043 QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) { 5044 if (bm == bitmap) { 5045 QLIST_REMOVE(bitmap, list); 5046 hbitmap_free(bitmap->bitmap); 5047 g_free(bitmap); 5048 return; 5049 } 5050 } 5051 } 5052 5053 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs) 5054 { 5055 BdrvDirtyBitmap *bm; 5056 BlockDirtyInfoList *list = NULL; 5057 BlockDirtyInfoList **plist = &list; 5058 5059 QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) { 5060 BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo)); 5061 BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList)); 5062 info->count = bdrv_get_dirty_count(bs, bm); 5063 info->granularity = 5064 ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap)); 5065 entry->value = info; 5066 *plist = entry; 5067 plist = &entry->next; 5068 } 5069 5070 return list; 5071 } 5072 5073 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector) 5074 { 5075 if (bitmap) { 5076 return hbitmap_get(bitmap->bitmap, sector); 5077 } else { 5078 return 0; 5079 } 5080 } 5081 5082 void bdrv_dirty_iter_init(BlockDriverState *bs, 5083 BdrvDirtyBitmap *bitmap, HBitmapIter *hbi) 5084 { 5085 hbitmap_iter_init(hbi, bitmap->bitmap, 0); 5086 } 5087 5088 void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, 5089 int nr_sectors) 5090 { 5091 BdrvDirtyBitmap *bitmap; 5092 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 5093 hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); 5094 } 5095 } 5096 5097 void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors) 5098 { 5099 BdrvDirtyBitmap *bitmap; 5100 QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { 5101 hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); 5102 } 5103 } 5104 5105 int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) 5106 { 5107 return hbitmap_count(bitmap->bitmap); 5108 } 5109 5110 /* Get a reference to bs */ 5111 void bdrv_ref(BlockDriverState *bs) 5112 { 5113 bs->refcnt++; 5114 } 5115 5116 /* Release a previously grabbed reference to bs. 5117 * If after releasing, reference count is zero, the BlockDriverState is 5118 * deleted. */ 5119 void bdrv_unref(BlockDriverState *bs) 5120 { 5121 assert(bs->refcnt > 0); 5122 if (--bs->refcnt == 0) { 5123 bdrv_delete(bs); 5124 } 5125 } 5126 5127 void bdrv_set_in_use(BlockDriverState *bs, int in_use) 5128 { 5129 assert(bs->in_use != in_use); 5130 bs->in_use = in_use; 5131 } 5132 5133 int bdrv_in_use(BlockDriverState *bs) 5134 { 5135 return bs->in_use; 5136 } 5137 5138 void bdrv_iostatus_enable(BlockDriverState *bs) 5139 { 5140 bs->iostatus_enabled = true; 5141 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 5142 } 5143 5144 /* The I/O status is only enabled if the drive explicitly 5145 * enables it _and_ the VM is configured to stop on errors */ 5146 bool bdrv_iostatus_is_enabled(const BlockDriverState *bs) 5147 { 5148 return (bs->iostatus_enabled && 5149 (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC || 5150 bs->on_write_error == BLOCKDEV_ON_ERROR_STOP || 5151 bs->on_read_error == BLOCKDEV_ON_ERROR_STOP)); 5152 } 5153 5154 void bdrv_iostatus_disable(BlockDriverState *bs) 5155 { 5156 bs->iostatus_enabled = false; 5157 } 5158 5159 void bdrv_iostatus_reset(BlockDriverState *bs) 5160 { 5161 if (bdrv_iostatus_is_enabled(bs)) { 5162 bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK; 5163 if (bs->job) { 5164 block_job_iostatus_reset(bs->job); 5165 } 5166 } 5167 } 5168 5169 void bdrv_iostatus_set_err(BlockDriverState *bs, int error) 5170 { 5171 assert(bdrv_iostatus_is_enabled(bs)); 5172 if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) { 5173 bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE : 5174 BLOCK_DEVICE_IO_STATUS_FAILED; 5175 } 5176 } 5177 5178 void 5179 bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes, 5180 enum BlockAcctType type) 5181 { 5182 assert(type < BDRV_MAX_IOTYPE); 5183 5184 cookie->bytes = bytes; 5185 cookie->start_time_ns = get_clock(); 5186 cookie->type = type; 5187 } 5188 5189 void 5190 bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie) 5191 { 5192 assert(cookie->type < BDRV_MAX_IOTYPE); 5193 5194 bs->nr_bytes[cookie->type] += cookie->bytes; 5195 bs->nr_ops[cookie->type]++; 5196 bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns; 5197 } 5198 5199 void bdrv_img_create(const char *filename, const char *fmt, 5200 const char *base_filename, const char *base_fmt, 5201 char *options, uint64_t img_size, int flags, 5202 Error **errp, bool quiet) 5203 { 5204 QEMUOptionParameter *param = NULL, *create_options = NULL; 5205 QEMUOptionParameter *backing_fmt, *backing_file, *size; 5206 BlockDriver *drv, *proto_drv; 5207 BlockDriver *backing_drv = NULL; 5208 Error *local_err = NULL; 5209 int ret = 0; 5210 5211 /* Find driver and parse its options */ 5212 drv = bdrv_find_format(fmt); 5213 if (!drv) { 5214 error_setg(errp, "Unknown file format '%s'", fmt); 5215 return; 5216 } 5217 5218 proto_drv = bdrv_find_protocol(filename, true); 5219 if (!proto_drv) { 5220 error_setg(errp, "Unknown protocol '%s'", filename); 5221 return; 5222 } 5223 5224 create_options = append_option_parameters(create_options, 5225 drv->create_options); 5226 create_options = append_option_parameters(create_options, 5227 proto_drv->create_options); 5228 5229 /* Create parameter list with default values */ 5230 param = parse_option_parameters("", create_options, param); 5231 5232 set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size); 5233 5234 /* Parse -o options */ 5235 if (options) { 5236 param = parse_option_parameters(options, create_options, param); 5237 if (param == NULL) { 5238 error_setg(errp, "Invalid options for file format '%s'.", fmt); 5239 goto out; 5240 } 5241 } 5242 5243 if (base_filename) { 5244 if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE, 5245 base_filename)) { 5246 error_setg(errp, "Backing file not supported for file format '%s'", 5247 fmt); 5248 goto out; 5249 } 5250 } 5251 5252 if (base_fmt) { 5253 if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) { 5254 error_setg(errp, "Backing file format not supported for file " 5255 "format '%s'", fmt); 5256 goto out; 5257 } 5258 } 5259 5260 backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE); 5261 if (backing_file && backing_file->value.s) { 5262 if (!strcmp(filename, backing_file->value.s)) { 5263 error_setg(errp, "Error: Trying to create an image with the " 5264 "same filename as the backing file"); 5265 goto out; 5266 } 5267 } 5268 5269 backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT); 5270 if (backing_fmt && backing_fmt->value.s) { 5271 backing_drv = bdrv_find_format(backing_fmt->value.s); 5272 if (!backing_drv) { 5273 error_setg(errp, "Unknown backing file format '%s'", 5274 backing_fmt->value.s); 5275 goto out; 5276 } 5277 } 5278 5279 // The size for the image must always be specified, with one exception: 5280 // If we are using a backing file, we can obtain the size from there 5281 size = get_option_parameter(param, BLOCK_OPT_SIZE); 5282 if (size && size->value.n == -1) { 5283 if (backing_file && backing_file->value.s) { 5284 BlockDriverState *bs; 5285 uint64_t size; 5286 char buf[32]; 5287 int back_flags; 5288 5289 /* backing files always opened read-only */ 5290 back_flags = 5291 flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); 5292 5293 bs = bdrv_new(""); 5294 5295 ret = bdrv_open(bs, backing_file->value.s, NULL, back_flags, 5296 backing_drv, &local_err); 5297 if (ret < 0) { 5298 error_setg_errno(errp, -ret, "Could not open '%s': %s", 5299 backing_file->value.s, 5300 error_get_pretty(local_err)); 5301 error_free(local_err); 5302 local_err = NULL; 5303 bdrv_unref(bs); 5304 goto out; 5305 } 5306 bdrv_get_geometry(bs, &size); 5307 size *= 512; 5308 5309 snprintf(buf, sizeof(buf), "%" PRId64, size); 5310 set_option_parameter(param, BLOCK_OPT_SIZE, buf); 5311 5312 bdrv_unref(bs); 5313 } else { 5314 error_setg(errp, "Image creation needs a size parameter"); 5315 goto out; 5316 } 5317 } 5318 5319 if (!quiet) { 5320 printf("Formatting '%s', fmt=%s ", filename, fmt); 5321 print_option_parameters(param); 5322 puts(""); 5323 } 5324 ret = bdrv_create(drv, filename, param, &local_err); 5325 if (ret == -EFBIG) { 5326 /* This is generally a better message than whatever the driver would 5327 * deliver (especially because of the cluster_size_hint), since that 5328 * is most probably not much different from "image too large". */ 5329 const char *cluster_size_hint = ""; 5330 if (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) { 5331 cluster_size_hint = " (try using a larger cluster size)"; 5332 } 5333 error_setg(errp, "The image size is too large for file format '%s'" 5334 "%s", fmt, cluster_size_hint); 5335 error_free(local_err); 5336 local_err = NULL; 5337 } 5338 5339 out: 5340 free_option_parameters(create_options); 5341 free_option_parameters(param); 5342 5343 if (error_is_set(&local_err)) { 5344 error_propagate(errp, local_err); 5345 } 5346 } 5347 5348 AioContext *bdrv_get_aio_context(BlockDriverState *bs) 5349 { 5350 /* Currently BlockDriverState always uses the main loop AioContext */ 5351 return qemu_get_aio_context(); 5352 } 5353 5354 void bdrv_add_before_write_notifier(BlockDriverState *bs, 5355 NotifierWithReturn *notifier) 5356 { 5357 notifier_with_return_list_add(&bs->before_write_notifiers, notifier); 5358 } 5359 5360 int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options) 5361 { 5362 if (bs->drv->bdrv_amend_options == NULL) { 5363 return -ENOTSUP; 5364 } 5365 return bs->drv->bdrv_amend_options(bs, options); 5366 } 5367 5368 /* Used to recurse on single child block filters. 5369 * Single child block filter will store their child in bs->file. 5370 */ 5371 bool bdrv_generic_is_first_non_filter(BlockDriverState *bs, 5372 BlockDriverState *candidate) 5373 { 5374 if (!bs->drv) { 5375 return false; 5376 } 5377 5378 if (!bs->drv->authorizations[BS_IS_A_FILTER]) { 5379 if (bs == candidate) { 5380 return true; 5381 } else { 5382 return false; 5383 } 5384 } 5385 5386 if (!bs->drv->authorizations[BS_FILTER_PASS_DOWN]) { 5387 return false; 5388 } 5389 5390 if (!bs->file) { 5391 return false; 5392 } 5393 5394 return bdrv_recurse_is_first_non_filter(bs->file, candidate); 5395 } 5396 5397 bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs, 5398 BlockDriverState *candidate) 5399 { 5400 if (bs->drv && bs->drv->bdrv_recurse_is_first_non_filter) { 5401 return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate); 5402 } 5403 5404 return bdrv_generic_is_first_non_filter(bs, candidate); 5405 } 5406 5407 /* This function checks if the candidate is the first non filter bs down it's 5408 * bs chain. Since we don't have pointers to parents it explore all bs chains 5409 * from the top. Some filters can choose not to pass down the recursion. 5410 */ 5411 bool bdrv_is_first_non_filter(BlockDriverState *candidate) 5412 { 5413 BlockDriverState *bs; 5414 5415 /* walk down the bs forest recursively */ 5416 QTAILQ_FOREACH(bs, &bdrv_states, device_list) { 5417 bool perm; 5418 5419 if (!bs->file) { 5420 continue; 5421 } 5422 5423 perm = bdrv_recurse_is_first_non_filter(bs->file, candidate); 5424 5425 /* candidate is the first non filter */ 5426 if (perm) { 5427 return true; 5428 } 5429 } 5430 5431 return false; 5432 } 5433