1 /* 2 * QEMU Enhanced Disk Format 3 * 4 * Copyright IBM, Corp. 2010 5 * 6 * Authors: 7 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> 8 * Anthony Liguori <aliguori@us.ibm.com> 9 * 10 * This work is licensed under the terms of the GNU LGPL, version 2 or later. 11 * See the COPYING.LIB file in the top-level directory. 12 * 13 */ 14 15 #include "qemu/timer.h" 16 #include "trace.h" 17 #include "qed.h" 18 #include "qapi/qmp/qerror.h" 19 #include "migration/migration.h" 20 21 static void qed_aio_cancel(BlockDriverAIOCB *blockacb) 22 { 23 QEDAIOCB *acb = (QEDAIOCB *)blockacb; 24 bool finished = false; 25 26 /* Wait for the request to finish */ 27 acb->finished = &finished; 28 while (!finished) { 29 qemu_aio_wait(); 30 } 31 } 32 33 static const AIOCBInfo qed_aiocb_info = { 34 .aiocb_size = sizeof(QEDAIOCB), 35 .cancel = qed_aio_cancel, 36 }; 37 38 static int bdrv_qed_probe(const uint8_t *buf, int buf_size, 39 const char *filename) 40 { 41 const QEDHeader *header = (const QEDHeader *)buf; 42 43 if (buf_size < sizeof(*header)) { 44 return 0; 45 } 46 if (le32_to_cpu(header->magic) != QED_MAGIC) { 47 return 0; 48 } 49 return 100; 50 } 51 52 /** 53 * Check whether an image format is raw 54 * 55 * @fmt: Backing file format, may be NULL 56 */ 57 static bool qed_fmt_is_raw(const char *fmt) 58 { 59 return fmt && strcmp(fmt, "raw") == 0; 60 } 61 62 static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu) 63 { 64 cpu->magic = le32_to_cpu(le->magic); 65 cpu->cluster_size = le32_to_cpu(le->cluster_size); 66 cpu->table_size = le32_to_cpu(le->table_size); 67 cpu->header_size = le32_to_cpu(le->header_size); 68 cpu->features = le64_to_cpu(le->features); 69 cpu->compat_features = le64_to_cpu(le->compat_features); 70 cpu->autoclear_features = le64_to_cpu(le->autoclear_features); 71 cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset); 72 cpu->image_size = le64_to_cpu(le->image_size); 73 cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset); 74 cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size); 75 } 76 77 static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le) 78 { 79 le->magic = cpu_to_le32(cpu->magic); 80 le->cluster_size = cpu_to_le32(cpu->cluster_size); 81 le->table_size = cpu_to_le32(cpu->table_size); 82 le->header_size = cpu_to_le32(cpu->header_size); 83 le->features = cpu_to_le64(cpu->features); 84 le->compat_features = cpu_to_le64(cpu->compat_features); 85 le->autoclear_features = cpu_to_le64(cpu->autoclear_features); 86 le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset); 87 le->image_size = cpu_to_le64(cpu->image_size); 88 le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset); 89 le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size); 90 } 91 92 int qed_write_header_sync(BDRVQEDState *s) 93 { 94 QEDHeader le; 95 int ret; 96 97 qed_header_cpu_to_le(&s->header, &le); 98 ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le)); 99 if (ret != sizeof(le)) { 100 return ret; 101 } 102 return 0; 103 } 104 105 typedef struct { 106 GenericCB gencb; 107 BDRVQEDState *s; 108 struct iovec iov; 109 QEMUIOVector qiov; 110 int nsectors; 111 uint8_t *buf; 112 } QEDWriteHeaderCB; 113 114 static void qed_write_header_cb(void *opaque, int ret) 115 { 116 QEDWriteHeaderCB *write_header_cb = opaque; 117 118 qemu_vfree(write_header_cb->buf); 119 gencb_complete(write_header_cb, ret); 120 } 121 122 static void qed_write_header_read_cb(void *opaque, int ret) 123 { 124 QEDWriteHeaderCB *write_header_cb = opaque; 125 BDRVQEDState *s = write_header_cb->s; 126 127 if (ret) { 128 qed_write_header_cb(write_header_cb, ret); 129 return; 130 } 131 132 /* Update header */ 133 qed_header_cpu_to_le(&s->header, (QEDHeader *)write_header_cb->buf); 134 135 bdrv_aio_writev(s->bs->file, 0, &write_header_cb->qiov, 136 write_header_cb->nsectors, qed_write_header_cb, 137 write_header_cb); 138 } 139 140 /** 141 * Update header in-place (does not rewrite backing filename or other strings) 142 * 143 * This function only updates known header fields in-place and does not affect 144 * extra data after the QED header. 145 */ 146 static void qed_write_header(BDRVQEDState *s, BlockDriverCompletionFunc cb, 147 void *opaque) 148 { 149 /* We must write full sectors for O_DIRECT but cannot necessarily generate 150 * the data following the header if an unrecognized compat feature is 151 * active. Therefore, first read the sectors containing the header, update 152 * them, and write back. 153 */ 154 155 int nsectors = (sizeof(QEDHeader) + BDRV_SECTOR_SIZE - 1) / 156 BDRV_SECTOR_SIZE; 157 size_t len = nsectors * BDRV_SECTOR_SIZE; 158 QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb), 159 cb, opaque); 160 161 write_header_cb->s = s; 162 write_header_cb->nsectors = nsectors; 163 write_header_cb->buf = qemu_blockalign(s->bs, len); 164 write_header_cb->iov.iov_base = write_header_cb->buf; 165 write_header_cb->iov.iov_len = len; 166 qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1); 167 168 bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors, 169 qed_write_header_read_cb, write_header_cb); 170 } 171 172 static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size) 173 { 174 uint64_t table_entries; 175 uint64_t l2_size; 176 177 table_entries = (table_size * cluster_size) / sizeof(uint64_t); 178 l2_size = table_entries * cluster_size; 179 180 return l2_size * table_entries; 181 } 182 183 static bool qed_is_cluster_size_valid(uint32_t cluster_size) 184 { 185 if (cluster_size < QED_MIN_CLUSTER_SIZE || 186 cluster_size > QED_MAX_CLUSTER_SIZE) { 187 return false; 188 } 189 if (cluster_size & (cluster_size - 1)) { 190 return false; /* not power of 2 */ 191 } 192 return true; 193 } 194 195 static bool qed_is_table_size_valid(uint32_t table_size) 196 { 197 if (table_size < QED_MIN_TABLE_SIZE || 198 table_size > QED_MAX_TABLE_SIZE) { 199 return false; 200 } 201 if (table_size & (table_size - 1)) { 202 return false; /* not power of 2 */ 203 } 204 return true; 205 } 206 207 static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size, 208 uint32_t table_size) 209 { 210 if (image_size % BDRV_SECTOR_SIZE != 0) { 211 return false; /* not multiple of sector size */ 212 } 213 if (image_size > qed_max_image_size(cluster_size, table_size)) { 214 return false; /* image is too large */ 215 } 216 return true; 217 } 218 219 /** 220 * Read a string of known length from the image file 221 * 222 * @file: Image file 223 * @offset: File offset to start of string, in bytes 224 * @n: String length in bytes 225 * @buf: Destination buffer 226 * @buflen: Destination buffer length in bytes 227 * @ret: 0 on success, -errno on failure 228 * 229 * The string is NUL-terminated. 230 */ 231 static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n, 232 char *buf, size_t buflen) 233 { 234 int ret; 235 if (n >= buflen) { 236 return -EINVAL; 237 } 238 ret = bdrv_pread(file, offset, buf, n); 239 if (ret < 0) { 240 return ret; 241 } 242 buf[n] = '\0'; 243 return 0; 244 } 245 246 /** 247 * Allocate new clusters 248 * 249 * @s: QED state 250 * @n: Number of contiguous clusters to allocate 251 * @ret: Offset of first allocated cluster 252 * 253 * This function only produces the offset where the new clusters should be 254 * written. It updates BDRVQEDState but does not make any changes to the image 255 * file. 256 */ 257 static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n) 258 { 259 uint64_t offset = s->file_size; 260 s->file_size += n * s->header.cluster_size; 261 return offset; 262 } 263 264 QEDTable *qed_alloc_table(BDRVQEDState *s) 265 { 266 /* Honor O_DIRECT memory alignment requirements */ 267 return qemu_blockalign(s->bs, 268 s->header.cluster_size * s->header.table_size); 269 } 270 271 /** 272 * Allocate a new zeroed L2 table 273 */ 274 static CachedL2Table *qed_new_l2_table(BDRVQEDState *s) 275 { 276 CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache); 277 278 l2_table->table = qed_alloc_table(s); 279 l2_table->offset = qed_alloc_clusters(s, s->header.table_size); 280 281 memset(l2_table->table->offsets, 0, 282 s->header.cluster_size * s->header.table_size); 283 return l2_table; 284 } 285 286 static void qed_aio_next_io(void *opaque, int ret); 287 288 static void qed_plug_allocating_write_reqs(BDRVQEDState *s) 289 { 290 assert(!s->allocating_write_reqs_plugged); 291 292 s->allocating_write_reqs_plugged = true; 293 } 294 295 static void qed_unplug_allocating_write_reqs(BDRVQEDState *s) 296 { 297 QEDAIOCB *acb; 298 299 assert(s->allocating_write_reqs_plugged); 300 301 s->allocating_write_reqs_plugged = false; 302 303 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 304 if (acb) { 305 qed_aio_next_io(acb, 0); 306 } 307 } 308 309 static void qed_finish_clear_need_check(void *opaque, int ret) 310 { 311 /* Do nothing */ 312 } 313 314 static void qed_flush_after_clear_need_check(void *opaque, int ret) 315 { 316 BDRVQEDState *s = opaque; 317 318 bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s); 319 320 /* No need to wait until flush completes */ 321 qed_unplug_allocating_write_reqs(s); 322 } 323 324 static void qed_clear_need_check(void *opaque, int ret) 325 { 326 BDRVQEDState *s = opaque; 327 328 if (ret) { 329 qed_unplug_allocating_write_reqs(s); 330 return; 331 } 332 333 s->header.features &= ~QED_F_NEED_CHECK; 334 qed_write_header(s, qed_flush_after_clear_need_check, s); 335 } 336 337 static void qed_need_check_timer_cb(void *opaque) 338 { 339 BDRVQEDState *s = opaque; 340 341 /* The timer should only fire when allocating writes have drained */ 342 assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs)); 343 344 trace_qed_need_check_timer_cb(s); 345 346 qed_plug_allocating_write_reqs(s); 347 348 /* Ensure writes are on disk before clearing flag */ 349 bdrv_aio_flush(s->bs, qed_clear_need_check, s); 350 } 351 352 static void qed_start_need_check_timer(BDRVQEDState *s) 353 { 354 trace_qed_start_need_check_timer(s); 355 356 /* Use vm_clock so we don't alter the image file while suspended for 357 * migration. 358 */ 359 qemu_mod_timer(s->need_check_timer, qemu_get_clock_ns(vm_clock) + 360 get_ticks_per_sec() * QED_NEED_CHECK_TIMEOUT); 361 } 362 363 /* It's okay to call this multiple times or when no timer is started */ 364 static void qed_cancel_need_check_timer(BDRVQEDState *s) 365 { 366 trace_qed_cancel_need_check_timer(s); 367 qemu_del_timer(s->need_check_timer); 368 } 369 370 static void bdrv_qed_rebind(BlockDriverState *bs) 371 { 372 BDRVQEDState *s = bs->opaque; 373 s->bs = bs; 374 } 375 376 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags) 377 { 378 BDRVQEDState *s = bs->opaque; 379 QEDHeader le_header; 380 int64_t file_size; 381 int ret; 382 383 s->bs = bs; 384 QSIMPLEQ_INIT(&s->allocating_write_reqs); 385 386 ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); 387 if (ret < 0) { 388 return ret; 389 } 390 qed_header_le_to_cpu(&le_header, &s->header); 391 392 if (s->header.magic != QED_MAGIC) { 393 return -EMEDIUMTYPE; 394 } 395 if (s->header.features & ~QED_FEATURE_MASK) { 396 /* image uses unsupported feature bits */ 397 char buf[64]; 398 snprintf(buf, sizeof(buf), "%" PRIx64, 399 s->header.features & ~QED_FEATURE_MASK); 400 qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 401 bs->device_name, "QED", buf); 402 return -ENOTSUP; 403 } 404 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 405 return -EINVAL; 406 } 407 408 /* Round down file size to the last cluster */ 409 file_size = bdrv_getlength(bs->file); 410 if (file_size < 0) { 411 return file_size; 412 } 413 s->file_size = qed_start_of_cluster(s, file_size); 414 415 if (!qed_is_table_size_valid(s->header.table_size)) { 416 return -EINVAL; 417 } 418 if (!qed_is_image_size_valid(s->header.image_size, 419 s->header.cluster_size, 420 s->header.table_size)) { 421 return -EINVAL; 422 } 423 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 424 return -EINVAL; 425 } 426 427 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 428 sizeof(uint64_t); 429 s->l2_shift = ffs(s->header.cluster_size) - 1; 430 s->l2_mask = s->table_nelems - 1; 431 s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1; 432 433 if ((s->header.features & QED_F_BACKING_FILE)) { 434 if ((uint64_t)s->header.backing_filename_offset + 435 s->header.backing_filename_size > 436 s->header.cluster_size * s->header.header_size) { 437 return -EINVAL; 438 } 439 440 ret = qed_read_string(bs->file, s->header.backing_filename_offset, 441 s->header.backing_filename_size, bs->backing_file, 442 sizeof(bs->backing_file)); 443 if (ret < 0) { 444 return ret; 445 } 446 447 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 448 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 449 } 450 } 451 452 /* Reset unknown autoclear feature bits. This is a backwards 453 * compatibility mechanism that allows images to be opened by older 454 * programs, which "knock out" unknown feature bits. When an image is 455 * opened by a newer program again it can detect that the autoclear 456 * feature is no longer valid. 457 */ 458 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 459 !bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) { 460 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 461 462 ret = qed_write_header_sync(s); 463 if (ret) { 464 return ret; 465 } 466 467 /* From here on only known autoclear feature bits are valid */ 468 bdrv_flush(bs->file); 469 } 470 471 s->l1_table = qed_alloc_table(s); 472 qed_init_l2_cache(&s->l2_cache); 473 474 ret = qed_read_l1_table_sync(s); 475 if (ret) { 476 goto out; 477 } 478 479 /* If image was not closed cleanly, check consistency */ 480 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { 481 /* Read-only images cannot be fixed. There is no risk of corruption 482 * since write operations are not possible. Therefore, allow 483 * potentially inconsistent images to be opened read-only. This can 484 * aid data recovery from an otherwise inconsistent image. 485 */ 486 if (!bdrv_is_read_only(bs->file) && 487 !(flags & BDRV_O_INCOMING)) { 488 BdrvCheckResult result = {0}; 489 490 ret = qed_check(s, &result, true); 491 if (ret) { 492 goto out; 493 } 494 } 495 } 496 497 s->need_check_timer = qemu_new_timer_ns(vm_clock, 498 qed_need_check_timer_cb, s); 499 500 out: 501 if (ret) { 502 qed_free_l2_cache(&s->l2_cache); 503 qemu_vfree(s->l1_table); 504 } 505 return ret; 506 } 507 508 /* We have nothing to do for QED reopen, stubs just return 509 * success */ 510 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 511 BlockReopenQueue *queue, Error **errp) 512 { 513 return 0; 514 } 515 516 static void bdrv_qed_close(BlockDriverState *bs) 517 { 518 BDRVQEDState *s = bs->opaque; 519 520 qed_cancel_need_check_timer(s); 521 qemu_free_timer(s->need_check_timer); 522 523 /* Ensure writes reach stable storage */ 524 bdrv_flush(bs->file); 525 526 /* Clean shutdown, no check required on next open */ 527 if (s->header.features & QED_F_NEED_CHECK) { 528 s->header.features &= ~QED_F_NEED_CHECK; 529 qed_write_header_sync(s); 530 } 531 532 qed_free_l2_cache(&s->l2_cache); 533 qemu_vfree(s->l1_table); 534 } 535 536 static int qed_create(const char *filename, uint32_t cluster_size, 537 uint64_t image_size, uint32_t table_size, 538 const char *backing_file, const char *backing_fmt) 539 { 540 QEDHeader header = { 541 .magic = QED_MAGIC, 542 .cluster_size = cluster_size, 543 .table_size = table_size, 544 .header_size = 1, 545 .features = 0, 546 .compat_features = 0, 547 .l1_table_offset = cluster_size, 548 .image_size = image_size, 549 }; 550 QEDHeader le_header; 551 uint8_t *l1_table = NULL; 552 size_t l1_size = header.cluster_size * header.table_size; 553 int ret = 0; 554 BlockDriverState *bs = NULL; 555 556 ret = bdrv_create_file(filename, NULL); 557 if (ret < 0) { 558 return ret; 559 } 560 561 ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR | BDRV_O_CACHE_WB); 562 if (ret < 0) { 563 return ret; 564 } 565 566 /* File must start empty and grow, check truncate is supported */ 567 ret = bdrv_truncate(bs, 0); 568 if (ret < 0) { 569 goto out; 570 } 571 572 if (backing_file) { 573 header.features |= QED_F_BACKING_FILE; 574 header.backing_filename_offset = sizeof(le_header); 575 header.backing_filename_size = strlen(backing_file); 576 577 if (qed_fmt_is_raw(backing_fmt)) { 578 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 579 } 580 } 581 582 qed_header_cpu_to_le(&header, &le_header); 583 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); 584 if (ret < 0) { 585 goto out; 586 } 587 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file, 588 header.backing_filename_size); 589 if (ret < 0) { 590 goto out; 591 } 592 593 l1_table = g_malloc0(l1_size); 594 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size); 595 if (ret < 0) { 596 goto out; 597 } 598 599 ret = 0; /* success */ 600 out: 601 g_free(l1_table); 602 bdrv_delete(bs); 603 return ret; 604 } 605 606 static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options) 607 { 608 uint64_t image_size = 0; 609 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 610 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 611 const char *backing_file = NULL; 612 const char *backing_fmt = NULL; 613 614 while (options && options->name) { 615 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 616 image_size = options->value.n; 617 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 618 backing_file = options->value.s; 619 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { 620 backing_fmt = options->value.s; 621 } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { 622 if (options->value.n) { 623 cluster_size = options->value.n; 624 } 625 } else if (!strcmp(options->name, BLOCK_OPT_TABLE_SIZE)) { 626 if (options->value.n) { 627 table_size = options->value.n; 628 } 629 } 630 options++; 631 } 632 633 if (!qed_is_cluster_size_valid(cluster_size)) { 634 fprintf(stderr, "QED cluster size must be within range [%u, %u] and power of 2\n", 635 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 636 return -EINVAL; 637 } 638 if (!qed_is_table_size_valid(table_size)) { 639 fprintf(stderr, "QED table size must be within range [%u, %u] and power of 2\n", 640 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 641 return -EINVAL; 642 } 643 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 644 fprintf(stderr, "QED image size must be a non-zero multiple of " 645 "cluster size and less than %" PRIu64 " bytes\n", 646 qed_max_image_size(cluster_size, table_size)); 647 return -EINVAL; 648 } 649 650 return qed_create(filename, cluster_size, image_size, table_size, 651 backing_file, backing_fmt); 652 } 653 654 typedef struct { 655 Coroutine *co; 656 int is_allocated; 657 int *pnum; 658 } QEDIsAllocatedCB; 659 660 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 661 { 662 QEDIsAllocatedCB *cb = opaque; 663 *cb->pnum = len / BDRV_SECTOR_SIZE; 664 cb->is_allocated = (ret == QED_CLUSTER_FOUND || ret == QED_CLUSTER_ZERO); 665 if (cb->co) { 666 qemu_coroutine_enter(cb->co, NULL); 667 } 668 } 669 670 static int coroutine_fn bdrv_qed_co_is_allocated(BlockDriverState *bs, 671 int64_t sector_num, 672 int nb_sectors, int *pnum) 673 { 674 BDRVQEDState *s = bs->opaque; 675 uint64_t pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 676 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 677 QEDIsAllocatedCB cb = { 678 .is_allocated = -1, 679 .pnum = pnum, 680 }; 681 QEDRequest request = { .l2_table = NULL }; 682 683 qed_find_cluster(s, &request, pos, len, qed_is_allocated_cb, &cb); 684 685 /* Now sleep if the callback wasn't invoked immediately */ 686 while (cb.is_allocated == -1) { 687 cb.co = qemu_coroutine_self(); 688 qemu_coroutine_yield(); 689 } 690 691 qed_unref_l2_cache_entry(request.l2_table); 692 693 return cb.is_allocated; 694 } 695 696 static int bdrv_qed_make_empty(BlockDriverState *bs) 697 { 698 return -ENOTSUP; 699 } 700 701 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 702 { 703 return acb->common.bs->opaque; 704 } 705 706 /** 707 * Read from the backing file or zero-fill if no backing file 708 * 709 * @s: QED state 710 * @pos: Byte position in device 711 * @qiov: Destination I/O vector 712 * @cb: Completion function 713 * @opaque: User data for completion function 714 * 715 * This function reads qiov->size bytes starting at pos from the backing file. 716 * If there is no backing file then zeroes are read. 717 */ 718 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 719 QEMUIOVector *qiov, 720 BlockDriverCompletionFunc *cb, void *opaque) 721 { 722 uint64_t backing_length = 0; 723 size_t size; 724 725 /* If there is a backing file, get its length. Treat the absence of a 726 * backing file like a zero length backing file. 727 */ 728 if (s->bs->backing_hd) { 729 int64_t l = bdrv_getlength(s->bs->backing_hd); 730 if (l < 0) { 731 cb(opaque, l); 732 return; 733 } 734 backing_length = l; 735 } 736 737 /* Zero all sectors if reading beyond the end of the backing file */ 738 if (pos >= backing_length || 739 pos + qiov->size > backing_length) { 740 qemu_iovec_memset(qiov, 0, 0, qiov->size); 741 } 742 743 /* Complete now if there are no backing file sectors to read */ 744 if (pos >= backing_length) { 745 cb(opaque, 0); 746 return; 747 } 748 749 /* If the read straddles the end of the backing file, shorten it */ 750 size = MIN((uint64_t)backing_length - pos, qiov->size); 751 752 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 753 bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE, 754 qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 755 } 756 757 typedef struct { 758 GenericCB gencb; 759 BDRVQEDState *s; 760 QEMUIOVector qiov; 761 struct iovec iov; 762 uint64_t offset; 763 } CopyFromBackingFileCB; 764 765 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 766 { 767 CopyFromBackingFileCB *copy_cb = opaque; 768 qemu_vfree(copy_cb->iov.iov_base); 769 gencb_complete(©_cb->gencb, ret); 770 } 771 772 static void qed_copy_from_backing_file_write(void *opaque, int ret) 773 { 774 CopyFromBackingFileCB *copy_cb = opaque; 775 BDRVQEDState *s = copy_cb->s; 776 777 if (ret) { 778 qed_copy_from_backing_file_cb(copy_cb, ret); 779 return; 780 } 781 782 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 783 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 784 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 785 qed_copy_from_backing_file_cb, copy_cb); 786 } 787 788 /** 789 * Copy data from backing file into the image 790 * 791 * @s: QED state 792 * @pos: Byte position in device 793 * @len: Number of bytes 794 * @offset: Byte offset in image file 795 * @cb: Completion function 796 * @opaque: User data for completion function 797 */ 798 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 799 uint64_t len, uint64_t offset, 800 BlockDriverCompletionFunc *cb, 801 void *opaque) 802 { 803 CopyFromBackingFileCB *copy_cb; 804 805 /* Skip copy entirely if there is no work to do */ 806 if (len == 0) { 807 cb(opaque, 0); 808 return; 809 } 810 811 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 812 copy_cb->s = s; 813 copy_cb->offset = offset; 814 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 815 copy_cb->iov.iov_len = len; 816 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 817 818 qed_read_backing_file(s, pos, ©_cb->qiov, 819 qed_copy_from_backing_file_write, copy_cb); 820 } 821 822 /** 823 * Link one or more contiguous clusters into a table 824 * 825 * @s: QED state 826 * @table: L2 table 827 * @index: First cluster index 828 * @n: Number of contiguous clusters 829 * @cluster: First cluster offset 830 * 831 * The cluster offset may be an allocated byte offset in the image file, the 832 * zero cluster marker, or the unallocated cluster marker. 833 */ 834 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 835 unsigned int n, uint64_t cluster) 836 { 837 int i; 838 for (i = index; i < index + n; i++) { 839 table->offsets[i] = cluster; 840 if (!qed_offset_is_unalloc_cluster(cluster) && 841 !qed_offset_is_zero_cluster(cluster)) { 842 cluster += s->header.cluster_size; 843 } 844 } 845 } 846 847 static void qed_aio_complete_bh(void *opaque) 848 { 849 QEDAIOCB *acb = opaque; 850 BlockDriverCompletionFunc *cb = acb->common.cb; 851 void *user_opaque = acb->common.opaque; 852 int ret = acb->bh_ret; 853 bool *finished = acb->finished; 854 855 qemu_bh_delete(acb->bh); 856 qemu_aio_release(acb); 857 858 /* Invoke callback */ 859 cb(user_opaque, ret); 860 861 /* Signal cancel completion */ 862 if (finished) { 863 *finished = true; 864 } 865 } 866 867 static void qed_aio_complete(QEDAIOCB *acb, int ret) 868 { 869 BDRVQEDState *s = acb_to_s(acb); 870 871 trace_qed_aio_complete(s, acb, ret); 872 873 /* Free resources */ 874 qemu_iovec_destroy(&acb->cur_qiov); 875 qed_unref_l2_cache_entry(acb->request.l2_table); 876 877 /* Free the buffer we may have allocated for zero writes */ 878 if (acb->flags & QED_AIOCB_ZERO) { 879 qemu_vfree(acb->qiov->iov[0].iov_base); 880 acb->qiov->iov[0].iov_base = NULL; 881 } 882 883 /* Arrange for a bh to invoke the completion function */ 884 acb->bh_ret = ret; 885 acb->bh = qemu_bh_new(qed_aio_complete_bh, acb); 886 qemu_bh_schedule(acb->bh); 887 888 /* Start next allocating write request waiting behind this one. Note that 889 * requests enqueue themselves when they first hit an unallocated cluster 890 * but they wait until the entire request is finished before waking up the 891 * next request in the queue. This ensures that we don't cycle through 892 * requests multiple times but rather finish one at a time completely. 893 */ 894 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 895 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 896 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 897 if (acb) { 898 qed_aio_next_io(acb, 0); 899 } else if (s->header.features & QED_F_NEED_CHECK) { 900 qed_start_need_check_timer(s); 901 } 902 } 903 } 904 905 /** 906 * Commit the current L2 table to the cache 907 */ 908 static void qed_commit_l2_update(void *opaque, int ret) 909 { 910 QEDAIOCB *acb = opaque; 911 BDRVQEDState *s = acb_to_s(acb); 912 CachedL2Table *l2_table = acb->request.l2_table; 913 uint64_t l2_offset = l2_table->offset; 914 915 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 916 917 /* This is guaranteed to succeed because we just committed the entry to the 918 * cache. 919 */ 920 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 921 assert(acb->request.l2_table != NULL); 922 923 qed_aio_next_io(opaque, ret); 924 } 925 926 /** 927 * Update L1 table with new L2 table offset and write it out 928 */ 929 static void qed_aio_write_l1_update(void *opaque, int ret) 930 { 931 QEDAIOCB *acb = opaque; 932 BDRVQEDState *s = acb_to_s(acb); 933 int index; 934 935 if (ret) { 936 qed_aio_complete(acb, ret); 937 return; 938 } 939 940 index = qed_l1_index(s, acb->cur_pos); 941 s->l1_table->offsets[index] = acb->request.l2_table->offset; 942 943 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 944 } 945 946 /** 947 * Update L2 table with new cluster offsets and write them out 948 */ 949 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 950 { 951 BDRVQEDState *s = acb_to_s(acb); 952 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 953 int index; 954 955 if (ret) { 956 goto err; 957 } 958 959 if (need_alloc) { 960 qed_unref_l2_cache_entry(acb->request.l2_table); 961 acb->request.l2_table = qed_new_l2_table(s); 962 } 963 964 index = qed_l2_index(s, acb->cur_pos); 965 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 966 offset); 967 968 if (need_alloc) { 969 /* Write out the whole new L2 table */ 970 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 971 qed_aio_write_l1_update, acb); 972 } else { 973 /* Write out only the updated part of the L2 table */ 974 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 975 qed_aio_next_io, acb); 976 } 977 return; 978 979 err: 980 qed_aio_complete(acb, ret); 981 } 982 983 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 984 { 985 QEDAIOCB *acb = opaque; 986 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 987 } 988 989 /** 990 * Flush new data clusters before updating the L2 table 991 * 992 * This flush is necessary when a backing file is in use. A crash during an 993 * allocating write could result in empty clusters in the image. If the write 994 * only touched a subregion of the cluster, then backing image sectors have 995 * been lost in the untouched region. The solution is to flush after writing a 996 * new data cluster and before updating the L2 table. 997 */ 998 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 999 { 1000 QEDAIOCB *acb = opaque; 1001 BDRVQEDState *s = acb_to_s(acb); 1002 1003 if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update_cb, opaque)) { 1004 qed_aio_complete(acb, -EIO); 1005 } 1006 } 1007 1008 /** 1009 * Write data to the image file 1010 */ 1011 static void qed_aio_write_main(void *opaque, int ret) 1012 { 1013 QEDAIOCB *acb = opaque; 1014 BDRVQEDState *s = acb_to_s(acb); 1015 uint64_t offset = acb->cur_cluster + 1016 qed_offset_into_cluster(s, acb->cur_pos); 1017 BlockDriverCompletionFunc *next_fn; 1018 1019 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1020 1021 if (ret) { 1022 qed_aio_complete(acb, ret); 1023 return; 1024 } 1025 1026 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1027 next_fn = qed_aio_next_io; 1028 } else { 1029 if (s->bs->backing_hd) { 1030 next_fn = qed_aio_write_flush_before_l2_update; 1031 } else { 1032 next_fn = qed_aio_write_l2_update_cb; 1033 } 1034 } 1035 1036 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1037 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1038 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1039 next_fn, acb); 1040 } 1041 1042 /** 1043 * Populate back untouched region of new data cluster 1044 */ 1045 static void qed_aio_write_postfill(void *opaque, int ret) 1046 { 1047 QEDAIOCB *acb = opaque; 1048 BDRVQEDState *s = acb_to_s(acb); 1049 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1050 uint64_t len = 1051 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1052 uint64_t offset = acb->cur_cluster + 1053 qed_offset_into_cluster(s, acb->cur_pos) + 1054 acb->cur_qiov.size; 1055 1056 if (ret) { 1057 qed_aio_complete(acb, ret); 1058 return; 1059 } 1060 1061 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1062 qed_copy_from_backing_file(s, start, len, offset, 1063 qed_aio_write_main, acb); 1064 } 1065 1066 /** 1067 * Populate front untouched region of new data cluster 1068 */ 1069 static void qed_aio_write_prefill(void *opaque, int ret) 1070 { 1071 QEDAIOCB *acb = opaque; 1072 BDRVQEDState *s = acb_to_s(acb); 1073 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1074 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1075 1076 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1077 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1078 qed_aio_write_postfill, acb); 1079 } 1080 1081 /** 1082 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1083 */ 1084 static bool qed_should_set_need_check(BDRVQEDState *s) 1085 { 1086 /* The flush before L2 update path ensures consistency */ 1087 if (s->bs->backing_hd) { 1088 return false; 1089 } 1090 1091 return !(s->header.features & QED_F_NEED_CHECK); 1092 } 1093 1094 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1095 { 1096 QEDAIOCB *acb = opaque; 1097 1098 if (ret) { 1099 qed_aio_complete(acb, ret); 1100 return; 1101 } 1102 1103 qed_aio_write_l2_update(acb, 0, 1); 1104 } 1105 1106 /** 1107 * Write new data cluster 1108 * 1109 * @acb: Write request 1110 * @len: Length in bytes 1111 * 1112 * This path is taken when writing to previously unallocated clusters. 1113 */ 1114 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1115 { 1116 BDRVQEDState *s = acb_to_s(acb); 1117 BlockDriverCompletionFunc *cb; 1118 1119 /* Cancel timer when the first allocating request comes in */ 1120 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1121 qed_cancel_need_check_timer(s); 1122 } 1123 1124 /* Freeze this request if another allocating write is in progress */ 1125 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1126 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1127 } 1128 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1129 s->allocating_write_reqs_plugged) { 1130 return; /* wait for existing request to finish */ 1131 } 1132 1133 acb->cur_nclusters = qed_bytes_to_clusters(s, 1134 qed_offset_into_cluster(s, acb->cur_pos) + len); 1135 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1136 1137 if (acb->flags & QED_AIOCB_ZERO) { 1138 /* Skip ahead if the clusters are already zero */ 1139 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1140 qed_aio_next_io(acb, 0); 1141 return; 1142 } 1143 1144 cb = qed_aio_write_zero_cluster; 1145 } else { 1146 cb = qed_aio_write_prefill; 1147 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1148 } 1149 1150 if (qed_should_set_need_check(s)) { 1151 s->header.features |= QED_F_NEED_CHECK; 1152 qed_write_header(s, cb, acb); 1153 } else { 1154 cb(acb, 0); 1155 } 1156 } 1157 1158 /** 1159 * Write data cluster in place 1160 * 1161 * @acb: Write request 1162 * @offset: Cluster offset in bytes 1163 * @len: Length in bytes 1164 * 1165 * This path is taken when writing to already allocated clusters. 1166 */ 1167 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1168 { 1169 /* Allocate buffer for zero writes */ 1170 if (acb->flags & QED_AIOCB_ZERO) { 1171 struct iovec *iov = acb->qiov->iov; 1172 1173 if (!iov->iov_base) { 1174 iov->iov_base = qemu_blockalign(acb->common.bs, iov->iov_len); 1175 memset(iov->iov_base, 0, iov->iov_len); 1176 } 1177 } 1178 1179 /* Calculate the I/O vector */ 1180 acb->cur_cluster = offset; 1181 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1182 1183 /* Do the actual write */ 1184 qed_aio_write_main(acb, 0); 1185 } 1186 1187 /** 1188 * Write data cluster 1189 * 1190 * @opaque: Write request 1191 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1192 * or -errno 1193 * @offset: Cluster offset in bytes 1194 * @len: Length in bytes 1195 * 1196 * Callback from qed_find_cluster(). 1197 */ 1198 static void qed_aio_write_data(void *opaque, int ret, 1199 uint64_t offset, size_t len) 1200 { 1201 QEDAIOCB *acb = opaque; 1202 1203 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1204 1205 acb->find_cluster_ret = ret; 1206 1207 switch (ret) { 1208 case QED_CLUSTER_FOUND: 1209 qed_aio_write_inplace(acb, offset, len); 1210 break; 1211 1212 case QED_CLUSTER_L2: 1213 case QED_CLUSTER_L1: 1214 case QED_CLUSTER_ZERO: 1215 qed_aio_write_alloc(acb, len); 1216 break; 1217 1218 default: 1219 qed_aio_complete(acb, ret); 1220 break; 1221 } 1222 } 1223 1224 /** 1225 * Read data cluster 1226 * 1227 * @opaque: Read request 1228 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1229 * or -errno 1230 * @offset: Cluster offset in bytes 1231 * @len: Length in bytes 1232 * 1233 * Callback from qed_find_cluster(). 1234 */ 1235 static void qed_aio_read_data(void *opaque, int ret, 1236 uint64_t offset, size_t len) 1237 { 1238 QEDAIOCB *acb = opaque; 1239 BDRVQEDState *s = acb_to_s(acb); 1240 BlockDriverState *bs = acb->common.bs; 1241 1242 /* Adjust offset into cluster */ 1243 offset += qed_offset_into_cluster(s, acb->cur_pos); 1244 1245 trace_qed_aio_read_data(s, acb, ret, offset, len); 1246 1247 if (ret < 0) { 1248 goto err; 1249 } 1250 1251 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1252 1253 /* Handle zero cluster and backing file reads */ 1254 if (ret == QED_CLUSTER_ZERO) { 1255 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1256 qed_aio_next_io(acb, 0); 1257 return; 1258 } else if (ret != QED_CLUSTER_FOUND) { 1259 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1260 qed_aio_next_io, acb); 1261 return; 1262 } 1263 1264 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1265 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1266 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1267 qed_aio_next_io, acb); 1268 return; 1269 1270 err: 1271 qed_aio_complete(acb, ret); 1272 } 1273 1274 /** 1275 * Begin next I/O or complete the request 1276 */ 1277 static void qed_aio_next_io(void *opaque, int ret) 1278 { 1279 QEDAIOCB *acb = opaque; 1280 BDRVQEDState *s = acb_to_s(acb); 1281 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1282 qed_aio_write_data : qed_aio_read_data; 1283 1284 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1285 1286 /* Handle I/O error */ 1287 if (ret) { 1288 qed_aio_complete(acb, ret); 1289 return; 1290 } 1291 1292 acb->qiov_offset += acb->cur_qiov.size; 1293 acb->cur_pos += acb->cur_qiov.size; 1294 qemu_iovec_reset(&acb->cur_qiov); 1295 1296 /* Complete request */ 1297 if (acb->cur_pos >= acb->end_pos) { 1298 qed_aio_complete(acb, 0); 1299 return; 1300 } 1301 1302 /* Find next cluster and start I/O */ 1303 qed_find_cluster(s, &acb->request, 1304 acb->cur_pos, acb->end_pos - acb->cur_pos, 1305 io_fn, acb); 1306 } 1307 1308 static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs, 1309 int64_t sector_num, 1310 QEMUIOVector *qiov, int nb_sectors, 1311 BlockDriverCompletionFunc *cb, 1312 void *opaque, int flags) 1313 { 1314 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1315 1316 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1317 opaque, flags); 1318 1319 acb->flags = flags; 1320 acb->finished = NULL; 1321 acb->qiov = qiov; 1322 acb->qiov_offset = 0; 1323 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1324 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1325 acb->request.l2_table = NULL; 1326 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1327 1328 /* Start request */ 1329 qed_aio_next_io(acb, 0); 1330 return &acb->common; 1331 } 1332 1333 static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1334 int64_t sector_num, 1335 QEMUIOVector *qiov, int nb_sectors, 1336 BlockDriverCompletionFunc *cb, 1337 void *opaque) 1338 { 1339 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1340 } 1341 1342 static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1343 int64_t sector_num, 1344 QEMUIOVector *qiov, int nb_sectors, 1345 BlockDriverCompletionFunc *cb, 1346 void *opaque) 1347 { 1348 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1349 opaque, QED_AIOCB_WRITE); 1350 } 1351 1352 typedef struct { 1353 Coroutine *co; 1354 int ret; 1355 bool done; 1356 } QEDWriteZeroesCB; 1357 1358 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret) 1359 { 1360 QEDWriteZeroesCB *cb = opaque; 1361 1362 cb->done = true; 1363 cb->ret = ret; 1364 if (cb->co) { 1365 qemu_coroutine_enter(cb->co, NULL); 1366 } 1367 } 1368 1369 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs, 1370 int64_t sector_num, 1371 int nb_sectors) 1372 { 1373 BlockDriverAIOCB *blockacb; 1374 BDRVQEDState *s = bs->opaque; 1375 QEDWriteZeroesCB cb = { .done = false }; 1376 QEMUIOVector qiov; 1377 struct iovec iov; 1378 1379 /* Refuse if there are untouched backing file sectors */ 1380 if (bs->backing_hd) { 1381 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) { 1382 return -ENOTSUP; 1383 } 1384 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) { 1385 return -ENOTSUP; 1386 } 1387 } 1388 1389 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1390 * then it will be allocated during request processing. 1391 */ 1392 iov.iov_base = NULL, 1393 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE, 1394 1395 qemu_iovec_init_external(&qiov, &iov, 1); 1396 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors, 1397 qed_co_write_zeroes_cb, &cb, 1398 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1399 if (!blockacb) { 1400 return -EIO; 1401 } 1402 if (!cb.done) { 1403 cb.co = qemu_coroutine_self(); 1404 qemu_coroutine_yield(); 1405 } 1406 assert(cb.done); 1407 return cb.ret; 1408 } 1409 1410 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1411 { 1412 BDRVQEDState *s = bs->opaque; 1413 uint64_t old_image_size; 1414 int ret; 1415 1416 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1417 s->header.table_size)) { 1418 return -EINVAL; 1419 } 1420 1421 /* Shrinking is currently not supported */ 1422 if ((uint64_t)offset < s->header.image_size) { 1423 return -ENOTSUP; 1424 } 1425 1426 old_image_size = s->header.image_size; 1427 s->header.image_size = offset; 1428 ret = qed_write_header_sync(s); 1429 if (ret < 0) { 1430 s->header.image_size = old_image_size; 1431 } 1432 return ret; 1433 } 1434 1435 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1436 { 1437 BDRVQEDState *s = bs->opaque; 1438 return s->header.image_size; 1439 } 1440 1441 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1442 { 1443 BDRVQEDState *s = bs->opaque; 1444 1445 memset(bdi, 0, sizeof(*bdi)); 1446 bdi->cluster_size = s->header.cluster_size; 1447 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1448 return 0; 1449 } 1450 1451 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1452 const char *backing_file, 1453 const char *backing_fmt) 1454 { 1455 BDRVQEDState *s = bs->opaque; 1456 QEDHeader new_header, le_header; 1457 void *buffer; 1458 size_t buffer_len, backing_file_len; 1459 int ret; 1460 1461 /* Refuse to set backing filename if unknown compat feature bits are 1462 * active. If the image uses an unknown compat feature then we may not 1463 * know the layout of data following the header structure and cannot safely 1464 * add a new string. 1465 */ 1466 if (backing_file && (s->header.compat_features & 1467 ~QED_COMPAT_FEATURE_MASK)) { 1468 return -ENOTSUP; 1469 } 1470 1471 memcpy(&new_header, &s->header, sizeof(new_header)); 1472 1473 new_header.features &= ~(QED_F_BACKING_FILE | 1474 QED_F_BACKING_FORMAT_NO_PROBE); 1475 1476 /* Adjust feature flags */ 1477 if (backing_file) { 1478 new_header.features |= QED_F_BACKING_FILE; 1479 1480 if (qed_fmt_is_raw(backing_fmt)) { 1481 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1482 } 1483 } 1484 1485 /* Calculate new header size */ 1486 backing_file_len = 0; 1487 1488 if (backing_file) { 1489 backing_file_len = strlen(backing_file); 1490 } 1491 1492 buffer_len = sizeof(new_header); 1493 new_header.backing_filename_offset = buffer_len; 1494 new_header.backing_filename_size = backing_file_len; 1495 buffer_len += backing_file_len; 1496 1497 /* Make sure we can rewrite header without failing */ 1498 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1499 return -ENOSPC; 1500 } 1501 1502 /* Prepare new header */ 1503 buffer = g_malloc(buffer_len); 1504 1505 qed_header_cpu_to_le(&new_header, &le_header); 1506 memcpy(buffer, &le_header, sizeof(le_header)); 1507 buffer_len = sizeof(le_header); 1508 1509 if (backing_file) { 1510 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1511 buffer_len += backing_file_len; 1512 } 1513 1514 /* Write new header */ 1515 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1516 g_free(buffer); 1517 if (ret == 0) { 1518 memcpy(&s->header, &new_header, sizeof(new_header)); 1519 } 1520 return ret; 1521 } 1522 1523 static void bdrv_qed_invalidate_cache(BlockDriverState *bs) 1524 { 1525 BDRVQEDState *s = bs->opaque; 1526 1527 bdrv_qed_close(bs); 1528 memset(s, 0, sizeof(BDRVQEDState)); 1529 bdrv_qed_open(bs, NULL, bs->open_flags); 1530 } 1531 1532 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1533 BdrvCheckMode fix) 1534 { 1535 BDRVQEDState *s = bs->opaque; 1536 1537 return qed_check(s, result, !!fix); 1538 } 1539 1540 static QEMUOptionParameter qed_create_options[] = { 1541 { 1542 .name = BLOCK_OPT_SIZE, 1543 .type = OPT_SIZE, 1544 .help = "Virtual disk size (in bytes)" 1545 }, { 1546 .name = BLOCK_OPT_BACKING_FILE, 1547 .type = OPT_STRING, 1548 .help = "File name of a base image" 1549 }, { 1550 .name = BLOCK_OPT_BACKING_FMT, 1551 .type = OPT_STRING, 1552 .help = "Image format of the base image" 1553 }, { 1554 .name = BLOCK_OPT_CLUSTER_SIZE, 1555 .type = OPT_SIZE, 1556 .help = "Cluster size (in bytes)", 1557 .value = { .n = QED_DEFAULT_CLUSTER_SIZE }, 1558 }, { 1559 .name = BLOCK_OPT_TABLE_SIZE, 1560 .type = OPT_SIZE, 1561 .help = "L1/L2 table size (in clusters)" 1562 }, 1563 { /* end of list */ } 1564 }; 1565 1566 static BlockDriver bdrv_qed = { 1567 .format_name = "qed", 1568 .instance_size = sizeof(BDRVQEDState), 1569 .create_options = qed_create_options, 1570 1571 .bdrv_probe = bdrv_qed_probe, 1572 .bdrv_rebind = bdrv_qed_rebind, 1573 .bdrv_open = bdrv_qed_open, 1574 .bdrv_close = bdrv_qed_close, 1575 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1576 .bdrv_create = bdrv_qed_create, 1577 .bdrv_co_is_allocated = bdrv_qed_co_is_allocated, 1578 .bdrv_make_empty = bdrv_qed_make_empty, 1579 .bdrv_aio_readv = bdrv_qed_aio_readv, 1580 .bdrv_aio_writev = bdrv_qed_aio_writev, 1581 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes, 1582 .bdrv_truncate = bdrv_qed_truncate, 1583 .bdrv_getlength = bdrv_qed_getlength, 1584 .bdrv_get_info = bdrv_qed_get_info, 1585 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1586 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1587 .bdrv_check = bdrv_qed_check, 1588 }; 1589 1590 static void bdrv_qed_init(void) 1591 { 1592 bdrv_register(&bdrv_qed); 1593 } 1594 1595 block_init(bdrv_qed_init); 1596