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 "qerror.h" 19 #include "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 AIOPool qed_aio_pool = { 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 static 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 int bdrv_qed_open(BlockDriverState *bs, int flags) 371 { 372 BDRVQEDState *s = bs->opaque; 373 QEDHeader le_header; 374 int64_t file_size; 375 int ret; 376 377 s->bs = bs; 378 QSIMPLEQ_INIT(&s->allocating_write_reqs); 379 380 ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); 381 if (ret < 0) { 382 return ret; 383 } 384 qed_header_le_to_cpu(&le_header, &s->header); 385 386 if (s->header.magic != QED_MAGIC) { 387 return -EINVAL; 388 } 389 if (s->header.features & ~QED_FEATURE_MASK) { 390 /* image uses unsupported feature bits */ 391 char buf[64]; 392 snprintf(buf, sizeof(buf), "%" PRIx64, 393 s->header.features & ~QED_FEATURE_MASK); 394 qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 395 bs->device_name, "QED", buf); 396 return -ENOTSUP; 397 } 398 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 399 return -EINVAL; 400 } 401 402 /* Round down file size to the last cluster */ 403 file_size = bdrv_getlength(bs->file); 404 if (file_size < 0) { 405 return file_size; 406 } 407 s->file_size = qed_start_of_cluster(s, file_size); 408 409 if (!qed_is_table_size_valid(s->header.table_size)) { 410 return -EINVAL; 411 } 412 if (!qed_is_image_size_valid(s->header.image_size, 413 s->header.cluster_size, 414 s->header.table_size)) { 415 return -EINVAL; 416 } 417 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 418 return -EINVAL; 419 } 420 421 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 422 sizeof(uint64_t); 423 s->l2_shift = ffs(s->header.cluster_size) - 1; 424 s->l2_mask = s->table_nelems - 1; 425 s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1; 426 427 if ((s->header.features & QED_F_BACKING_FILE)) { 428 if ((uint64_t)s->header.backing_filename_offset + 429 s->header.backing_filename_size > 430 s->header.cluster_size * s->header.header_size) { 431 return -EINVAL; 432 } 433 434 ret = qed_read_string(bs->file, s->header.backing_filename_offset, 435 s->header.backing_filename_size, bs->backing_file, 436 sizeof(bs->backing_file)); 437 if (ret < 0) { 438 return ret; 439 } 440 441 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 442 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 443 } 444 } 445 446 /* Reset unknown autoclear feature bits. This is a backwards 447 * compatibility mechanism that allows images to be opened by older 448 * programs, which "knock out" unknown feature bits. When an image is 449 * opened by a newer program again it can detect that the autoclear 450 * feature is no longer valid. 451 */ 452 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 453 !bdrv_is_read_only(bs->file)) { 454 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 455 456 ret = qed_write_header_sync(s); 457 if (ret) { 458 return ret; 459 } 460 461 /* From here on only known autoclear feature bits are valid */ 462 bdrv_flush(bs->file); 463 } 464 465 s->l1_table = qed_alloc_table(s); 466 qed_init_l2_cache(&s->l2_cache); 467 468 ret = qed_read_l1_table_sync(s); 469 if (ret) { 470 goto out; 471 } 472 473 /* If image was not closed cleanly, check consistency */ 474 if (s->header.features & QED_F_NEED_CHECK) { 475 /* Read-only images cannot be fixed. There is no risk of corruption 476 * since write operations are not possible. Therefore, allow 477 * potentially inconsistent images to be opened read-only. This can 478 * aid data recovery from an otherwise inconsistent image. 479 */ 480 if (!bdrv_is_read_only(bs->file)) { 481 BdrvCheckResult result = {0}; 482 483 ret = qed_check(s, &result, true); 484 if (ret) { 485 goto out; 486 } 487 if (!result.corruptions && !result.check_errors) { 488 /* Ensure fixes reach storage before clearing check bit */ 489 bdrv_flush(s->bs); 490 491 s->header.features &= ~QED_F_NEED_CHECK; 492 qed_write_header_sync(s); 493 } 494 } 495 } 496 497 s->need_check_timer = qemu_new_timer_ns(vm_clock, 498 qed_need_check_timer_cb, s); 499 500 error_set(&s->migration_blocker, 501 QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED, 502 "qed", bs->device_name, "live migration"); 503 migrate_add_blocker(s->migration_blocker); 504 505 506 out: 507 if (ret) { 508 qed_free_l2_cache(&s->l2_cache); 509 qemu_vfree(s->l1_table); 510 } 511 return ret; 512 } 513 514 static void bdrv_qed_close(BlockDriverState *bs) 515 { 516 BDRVQEDState *s = bs->opaque; 517 518 migrate_del_blocker(s->migration_blocker); 519 error_free(s->migration_blocker); 520 521 qed_cancel_need_check_timer(s); 522 qemu_free_timer(s->need_check_timer); 523 524 /* Ensure writes reach stable storage */ 525 bdrv_flush(bs->file); 526 527 /* Clean shutdown, no check required on next open */ 528 if (s->header.features & QED_F_NEED_CHECK) { 529 s->header.features &= ~QED_F_NEED_CHECK; 530 qed_write_header_sync(s); 531 } 532 533 qed_free_l2_cache(&s->l2_cache); 534 qemu_vfree(s->l1_table); 535 } 536 537 static int qed_create(const char *filename, uint32_t cluster_size, 538 uint64_t image_size, uint32_t table_size, 539 const char *backing_file, const char *backing_fmt) 540 { 541 QEDHeader header = { 542 .magic = QED_MAGIC, 543 .cluster_size = cluster_size, 544 .table_size = table_size, 545 .header_size = 1, 546 .features = 0, 547 .compat_features = 0, 548 .l1_table_offset = cluster_size, 549 .image_size = image_size, 550 }; 551 QEDHeader le_header; 552 uint8_t *l1_table = NULL; 553 size_t l1_size = header.cluster_size * header.table_size; 554 int ret = 0; 555 BlockDriverState *bs = NULL; 556 557 ret = bdrv_create_file(filename, NULL); 558 if (ret < 0) { 559 return ret; 560 } 561 562 ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR | BDRV_O_CACHE_WB); 563 if (ret < 0) { 564 return ret; 565 } 566 567 /* File must start empty and grow, check truncate is supported */ 568 ret = bdrv_truncate(bs, 0); 569 if (ret < 0) { 570 goto out; 571 } 572 573 if (backing_file) { 574 header.features |= QED_F_BACKING_FILE; 575 header.backing_filename_offset = sizeof(le_header); 576 header.backing_filename_size = strlen(backing_file); 577 578 if (qed_fmt_is_raw(backing_fmt)) { 579 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 580 } 581 } 582 583 qed_header_cpu_to_le(&header, &le_header); 584 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); 585 if (ret < 0) { 586 goto out; 587 } 588 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file, 589 header.backing_filename_size); 590 if (ret < 0) { 591 goto out; 592 } 593 594 l1_table = g_malloc0(l1_size); 595 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size); 596 if (ret < 0) { 597 goto out; 598 } 599 600 ret = 0; /* success */ 601 out: 602 g_free(l1_table); 603 bdrv_delete(bs); 604 return ret; 605 } 606 607 static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options) 608 { 609 uint64_t image_size = 0; 610 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 611 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 612 const char *backing_file = NULL; 613 const char *backing_fmt = NULL; 614 615 while (options && options->name) { 616 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 617 image_size = options->value.n; 618 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 619 backing_file = options->value.s; 620 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) { 621 backing_fmt = options->value.s; 622 } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) { 623 if (options->value.n) { 624 cluster_size = options->value.n; 625 } 626 } else if (!strcmp(options->name, BLOCK_OPT_TABLE_SIZE)) { 627 if (options->value.n) { 628 table_size = options->value.n; 629 } 630 } 631 options++; 632 } 633 634 if (!qed_is_cluster_size_valid(cluster_size)) { 635 fprintf(stderr, "QED cluster size must be within range [%u, %u] and power of 2\n", 636 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 637 return -EINVAL; 638 } 639 if (!qed_is_table_size_valid(table_size)) { 640 fprintf(stderr, "QED table size must be within range [%u, %u] and power of 2\n", 641 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 642 return -EINVAL; 643 } 644 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 645 fprintf(stderr, "QED image size must be a non-zero multiple of " 646 "cluster size and less than %" PRIu64 " bytes\n", 647 qed_max_image_size(cluster_size, table_size)); 648 return -EINVAL; 649 } 650 651 return qed_create(filename, cluster_size, image_size, table_size, 652 backing_file, backing_fmt); 653 } 654 655 typedef struct { 656 Coroutine *co; 657 int is_allocated; 658 int *pnum; 659 } QEDIsAllocatedCB; 660 661 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 662 { 663 QEDIsAllocatedCB *cb = opaque; 664 *cb->pnum = len / BDRV_SECTOR_SIZE; 665 cb->is_allocated = (ret == QED_CLUSTER_FOUND || ret == QED_CLUSTER_ZERO); 666 if (cb->co) { 667 qemu_coroutine_enter(cb->co, NULL); 668 } 669 } 670 671 static int coroutine_fn bdrv_qed_co_is_allocated(BlockDriverState *bs, 672 int64_t sector_num, 673 int nb_sectors, int *pnum) 674 { 675 BDRVQEDState *s = bs->opaque; 676 uint64_t pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 677 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 678 QEDIsAllocatedCB cb = { 679 .is_allocated = -1, 680 .pnum = pnum, 681 }; 682 QEDRequest request = { .l2_table = NULL }; 683 684 qed_find_cluster(s, &request, pos, len, qed_is_allocated_cb, &cb); 685 686 /* Now sleep if the callback wasn't invoked immediately */ 687 while (cb.is_allocated == -1) { 688 cb.co = qemu_coroutine_self(); 689 qemu_coroutine_yield(); 690 } 691 692 qed_unref_l2_cache_entry(request.l2_table); 693 694 return cb.is_allocated; 695 } 696 697 static int bdrv_qed_make_empty(BlockDriverState *bs) 698 { 699 return -ENOTSUP; 700 } 701 702 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 703 { 704 return acb->common.bs->opaque; 705 } 706 707 /** 708 * Read from the backing file or zero-fill if no backing file 709 * 710 * @s: QED state 711 * @pos: Byte position in device 712 * @qiov: Destination I/O vector 713 * @cb: Completion function 714 * @opaque: User data for completion function 715 * 716 * This function reads qiov->size bytes starting at pos from the backing file. 717 * If there is no backing file then zeroes are read. 718 */ 719 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 720 QEMUIOVector *qiov, 721 BlockDriverCompletionFunc *cb, void *opaque) 722 { 723 uint64_t backing_length = 0; 724 size_t size; 725 726 /* If there is a backing file, get its length. Treat the absence of a 727 * backing file like a zero length backing file. 728 */ 729 if (s->bs->backing_hd) { 730 int64_t l = bdrv_getlength(s->bs->backing_hd); 731 if (l < 0) { 732 cb(opaque, l); 733 return; 734 } 735 backing_length = l; 736 } 737 738 /* Zero all sectors if reading beyond the end of the backing file */ 739 if (pos >= backing_length || 740 pos + qiov->size > backing_length) { 741 qemu_iovec_memset(qiov, 0, qiov->size); 742 } 743 744 /* Complete now if there are no backing file sectors to read */ 745 if (pos >= backing_length) { 746 cb(opaque, 0); 747 return; 748 } 749 750 /* If the read straddles the end of the backing file, shorten it */ 751 size = MIN((uint64_t)backing_length - pos, qiov->size); 752 753 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING); 754 bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE, 755 qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 756 } 757 758 typedef struct { 759 GenericCB gencb; 760 BDRVQEDState *s; 761 QEMUIOVector qiov; 762 struct iovec iov; 763 uint64_t offset; 764 } CopyFromBackingFileCB; 765 766 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 767 { 768 CopyFromBackingFileCB *copy_cb = opaque; 769 qemu_vfree(copy_cb->iov.iov_base); 770 gencb_complete(©_cb->gencb, ret); 771 } 772 773 static void qed_copy_from_backing_file_write(void *opaque, int ret) 774 { 775 CopyFromBackingFileCB *copy_cb = opaque; 776 BDRVQEDState *s = copy_cb->s; 777 778 if (ret) { 779 qed_copy_from_backing_file_cb(copy_cb, ret); 780 return; 781 } 782 783 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 784 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 785 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 786 qed_copy_from_backing_file_cb, copy_cb); 787 } 788 789 /** 790 * Copy data from backing file into the image 791 * 792 * @s: QED state 793 * @pos: Byte position in device 794 * @len: Number of bytes 795 * @offset: Byte offset in image file 796 * @cb: Completion function 797 * @opaque: User data for completion function 798 */ 799 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 800 uint64_t len, uint64_t offset, 801 BlockDriverCompletionFunc *cb, 802 void *opaque) 803 { 804 CopyFromBackingFileCB *copy_cb; 805 806 /* Skip copy entirely if there is no work to do */ 807 if (len == 0) { 808 cb(opaque, 0); 809 return; 810 } 811 812 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 813 copy_cb->s = s; 814 copy_cb->offset = offset; 815 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 816 copy_cb->iov.iov_len = len; 817 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 818 819 qed_read_backing_file(s, pos, ©_cb->qiov, 820 qed_copy_from_backing_file_write, copy_cb); 821 } 822 823 /** 824 * Link one or more contiguous clusters into a table 825 * 826 * @s: QED state 827 * @table: L2 table 828 * @index: First cluster index 829 * @n: Number of contiguous clusters 830 * @cluster: First cluster offset 831 * 832 * The cluster offset may be an allocated byte offset in the image file, the 833 * zero cluster marker, or the unallocated cluster marker. 834 */ 835 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 836 unsigned int n, uint64_t cluster) 837 { 838 int i; 839 for (i = index; i < index + n; i++) { 840 table->offsets[i] = cluster; 841 if (!qed_offset_is_unalloc_cluster(cluster) && 842 !qed_offset_is_zero_cluster(cluster)) { 843 cluster += s->header.cluster_size; 844 } 845 } 846 } 847 848 static void qed_aio_complete_bh(void *opaque) 849 { 850 QEDAIOCB *acb = opaque; 851 BlockDriverCompletionFunc *cb = acb->common.cb; 852 void *user_opaque = acb->common.opaque; 853 int ret = acb->bh_ret; 854 bool *finished = acb->finished; 855 856 qemu_bh_delete(acb->bh); 857 qemu_aio_release(acb); 858 859 /* Invoke callback */ 860 cb(user_opaque, ret); 861 862 /* Signal cancel completion */ 863 if (finished) { 864 *finished = true; 865 } 866 } 867 868 static void qed_aio_complete(QEDAIOCB *acb, int ret) 869 { 870 BDRVQEDState *s = acb_to_s(acb); 871 872 trace_qed_aio_complete(s, acb, ret); 873 874 /* Free resources */ 875 qemu_iovec_destroy(&acb->cur_qiov); 876 qed_unref_l2_cache_entry(acb->request.l2_table); 877 878 /* Arrange for a bh to invoke the completion function */ 879 acb->bh_ret = ret; 880 acb->bh = qemu_bh_new(qed_aio_complete_bh, acb); 881 qemu_bh_schedule(acb->bh); 882 883 /* Start next allocating write request waiting behind this one. Note that 884 * requests enqueue themselves when they first hit an unallocated cluster 885 * but they wait until the entire request is finished before waking up the 886 * next request in the queue. This ensures that we don't cycle through 887 * requests multiple times but rather finish one at a time completely. 888 */ 889 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 890 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 891 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 892 if (acb) { 893 qed_aio_next_io(acb, 0); 894 } else if (s->header.features & QED_F_NEED_CHECK) { 895 qed_start_need_check_timer(s); 896 } 897 } 898 } 899 900 /** 901 * Commit the current L2 table to the cache 902 */ 903 static void qed_commit_l2_update(void *opaque, int ret) 904 { 905 QEDAIOCB *acb = opaque; 906 BDRVQEDState *s = acb_to_s(acb); 907 CachedL2Table *l2_table = acb->request.l2_table; 908 uint64_t l2_offset = l2_table->offset; 909 910 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 911 912 /* This is guaranteed to succeed because we just committed the entry to the 913 * cache. 914 */ 915 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 916 assert(acb->request.l2_table != NULL); 917 918 qed_aio_next_io(opaque, ret); 919 } 920 921 /** 922 * Update L1 table with new L2 table offset and write it out 923 */ 924 static void qed_aio_write_l1_update(void *opaque, int ret) 925 { 926 QEDAIOCB *acb = opaque; 927 BDRVQEDState *s = acb_to_s(acb); 928 int index; 929 930 if (ret) { 931 qed_aio_complete(acb, ret); 932 return; 933 } 934 935 index = qed_l1_index(s, acb->cur_pos); 936 s->l1_table->offsets[index] = acb->request.l2_table->offset; 937 938 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 939 } 940 941 /** 942 * Update L2 table with new cluster offsets and write them out 943 */ 944 static void qed_aio_write_l2_update(void *opaque, int ret) 945 { 946 QEDAIOCB *acb = opaque; 947 BDRVQEDState *s = acb_to_s(acb); 948 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 949 int index; 950 951 if (ret) { 952 goto err; 953 } 954 955 if (need_alloc) { 956 qed_unref_l2_cache_entry(acb->request.l2_table); 957 acb->request.l2_table = qed_new_l2_table(s); 958 } 959 960 index = qed_l2_index(s, acb->cur_pos); 961 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 962 acb->cur_cluster); 963 964 if (need_alloc) { 965 /* Write out the whole new L2 table */ 966 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 967 qed_aio_write_l1_update, acb); 968 } else { 969 /* Write out only the updated part of the L2 table */ 970 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 971 qed_aio_next_io, acb); 972 } 973 return; 974 975 err: 976 qed_aio_complete(acb, ret); 977 } 978 979 /** 980 * Flush new data clusters before updating the L2 table 981 * 982 * This flush is necessary when a backing file is in use. A crash during an 983 * allocating write could result in empty clusters in the image. If the write 984 * only touched a subregion of the cluster, then backing image sectors have 985 * been lost in the untouched region. The solution is to flush after writing a 986 * new data cluster and before updating the L2 table. 987 */ 988 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 989 { 990 QEDAIOCB *acb = opaque; 991 BDRVQEDState *s = acb_to_s(acb); 992 993 if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update, opaque)) { 994 qed_aio_complete(acb, -EIO); 995 } 996 } 997 998 /** 999 * Write data to the image file 1000 */ 1001 static void qed_aio_write_main(void *opaque, int ret) 1002 { 1003 QEDAIOCB *acb = opaque; 1004 BDRVQEDState *s = acb_to_s(acb); 1005 uint64_t offset = acb->cur_cluster + 1006 qed_offset_into_cluster(s, acb->cur_pos); 1007 BlockDriverCompletionFunc *next_fn; 1008 1009 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1010 1011 if (ret) { 1012 qed_aio_complete(acb, ret); 1013 return; 1014 } 1015 1016 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1017 next_fn = qed_aio_next_io; 1018 } else { 1019 if (s->bs->backing_hd) { 1020 next_fn = qed_aio_write_flush_before_l2_update; 1021 } else { 1022 next_fn = qed_aio_write_l2_update; 1023 } 1024 } 1025 1026 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1027 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1028 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1029 next_fn, acb); 1030 } 1031 1032 /** 1033 * Populate back untouched region of new data cluster 1034 */ 1035 static void qed_aio_write_postfill(void *opaque, int ret) 1036 { 1037 QEDAIOCB *acb = opaque; 1038 BDRVQEDState *s = acb_to_s(acb); 1039 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1040 uint64_t len = 1041 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1042 uint64_t offset = acb->cur_cluster + 1043 qed_offset_into_cluster(s, acb->cur_pos) + 1044 acb->cur_qiov.size; 1045 1046 if (ret) { 1047 qed_aio_complete(acb, ret); 1048 return; 1049 } 1050 1051 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1052 qed_copy_from_backing_file(s, start, len, offset, 1053 qed_aio_write_main, acb); 1054 } 1055 1056 /** 1057 * Populate front untouched region of new data cluster 1058 */ 1059 static void qed_aio_write_prefill(void *opaque, int ret) 1060 { 1061 QEDAIOCB *acb = opaque; 1062 BDRVQEDState *s = acb_to_s(acb); 1063 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1064 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1065 1066 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1067 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1068 qed_aio_write_postfill, acb); 1069 } 1070 1071 /** 1072 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1073 */ 1074 static bool qed_should_set_need_check(BDRVQEDState *s) 1075 { 1076 /* The flush before L2 update path ensures consistency */ 1077 if (s->bs->backing_hd) { 1078 return false; 1079 } 1080 1081 return !(s->header.features & QED_F_NEED_CHECK); 1082 } 1083 1084 /** 1085 * Write new data cluster 1086 * 1087 * @acb: Write request 1088 * @len: Length in bytes 1089 * 1090 * This path is taken when writing to previously unallocated clusters. 1091 */ 1092 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1093 { 1094 BDRVQEDState *s = acb_to_s(acb); 1095 1096 /* Cancel timer when the first allocating request comes in */ 1097 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1098 qed_cancel_need_check_timer(s); 1099 } 1100 1101 /* Freeze this request if another allocating write is in progress */ 1102 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1103 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1104 } 1105 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1106 s->allocating_write_reqs_plugged) { 1107 return; /* wait for existing request to finish */ 1108 } 1109 1110 acb->cur_nclusters = qed_bytes_to_clusters(s, 1111 qed_offset_into_cluster(s, acb->cur_pos) + len); 1112 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1113 qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1114 1115 if (qed_should_set_need_check(s)) { 1116 s->header.features |= QED_F_NEED_CHECK; 1117 qed_write_header(s, qed_aio_write_prefill, acb); 1118 } else { 1119 qed_aio_write_prefill(acb, 0); 1120 } 1121 } 1122 1123 /** 1124 * Write data cluster in place 1125 * 1126 * @acb: Write request 1127 * @offset: Cluster offset in bytes 1128 * @len: Length in bytes 1129 * 1130 * This path is taken when writing to already allocated clusters. 1131 */ 1132 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1133 { 1134 /* Calculate the I/O vector */ 1135 acb->cur_cluster = offset; 1136 qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1137 1138 /* Do the actual write */ 1139 qed_aio_write_main(acb, 0); 1140 } 1141 1142 /** 1143 * Write data cluster 1144 * 1145 * @opaque: Write request 1146 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1147 * or -errno 1148 * @offset: Cluster offset in bytes 1149 * @len: Length in bytes 1150 * 1151 * Callback from qed_find_cluster(). 1152 */ 1153 static void qed_aio_write_data(void *opaque, int ret, 1154 uint64_t offset, size_t len) 1155 { 1156 QEDAIOCB *acb = opaque; 1157 1158 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1159 1160 acb->find_cluster_ret = ret; 1161 1162 switch (ret) { 1163 case QED_CLUSTER_FOUND: 1164 qed_aio_write_inplace(acb, offset, len); 1165 break; 1166 1167 case QED_CLUSTER_L2: 1168 case QED_CLUSTER_L1: 1169 case QED_CLUSTER_ZERO: 1170 qed_aio_write_alloc(acb, len); 1171 break; 1172 1173 default: 1174 qed_aio_complete(acb, ret); 1175 break; 1176 } 1177 } 1178 1179 /** 1180 * Read data cluster 1181 * 1182 * @opaque: Read request 1183 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1184 * or -errno 1185 * @offset: Cluster offset in bytes 1186 * @len: Length in bytes 1187 * 1188 * Callback from qed_find_cluster(). 1189 */ 1190 static void qed_aio_read_data(void *opaque, int ret, 1191 uint64_t offset, size_t len) 1192 { 1193 QEDAIOCB *acb = opaque; 1194 BDRVQEDState *s = acb_to_s(acb); 1195 BlockDriverState *bs = acb->common.bs; 1196 1197 /* Adjust offset into cluster */ 1198 offset += qed_offset_into_cluster(s, acb->cur_pos); 1199 1200 trace_qed_aio_read_data(s, acb, ret, offset, len); 1201 1202 if (ret < 0) { 1203 goto err; 1204 } 1205 1206 qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1207 1208 /* Handle zero cluster and backing file reads */ 1209 if (ret == QED_CLUSTER_ZERO) { 1210 qemu_iovec_memset(&acb->cur_qiov, 0, acb->cur_qiov.size); 1211 qed_aio_next_io(acb, 0); 1212 return; 1213 } else if (ret != QED_CLUSTER_FOUND) { 1214 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1215 qed_aio_next_io, acb); 1216 return; 1217 } 1218 1219 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1220 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1221 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1222 qed_aio_next_io, acb); 1223 return; 1224 1225 err: 1226 qed_aio_complete(acb, ret); 1227 } 1228 1229 /** 1230 * Begin next I/O or complete the request 1231 */ 1232 static void qed_aio_next_io(void *opaque, int ret) 1233 { 1234 QEDAIOCB *acb = opaque; 1235 BDRVQEDState *s = acb_to_s(acb); 1236 QEDFindClusterFunc *io_fn = 1237 acb->is_write ? qed_aio_write_data : qed_aio_read_data; 1238 1239 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1240 1241 /* Handle I/O error */ 1242 if (ret) { 1243 qed_aio_complete(acb, ret); 1244 return; 1245 } 1246 1247 acb->qiov_offset += acb->cur_qiov.size; 1248 acb->cur_pos += acb->cur_qiov.size; 1249 qemu_iovec_reset(&acb->cur_qiov); 1250 1251 /* Complete request */ 1252 if (acb->cur_pos >= acb->end_pos) { 1253 qed_aio_complete(acb, 0); 1254 return; 1255 } 1256 1257 /* Find next cluster and start I/O */ 1258 qed_find_cluster(s, &acb->request, 1259 acb->cur_pos, acb->end_pos - acb->cur_pos, 1260 io_fn, acb); 1261 } 1262 1263 static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs, 1264 int64_t sector_num, 1265 QEMUIOVector *qiov, int nb_sectors, 1266 BlockDriverCompletionFunc *cb, 1267 void *opaque, bool is_write) 1268 { 1269 QEDAIOCB *acb = qemu_aio_get(&qed_aio_pool, bs, cb, opaque); 1270 1271 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1272 opaque, is_write); 1273 1274 acb->is_write = is_write; 1275 acb->finished = NULL; 1276 acb->qiov = qiov; 1277 acb->qiov_offset = 0; 1278 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1279 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1280 acb->request.l2_table = NULL; 1281 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1282 1283 /* Start request */ 1284 qed_aio_next_io(acb, 0); 1285 return &acb->common; 1286 } 1287 1288 static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1289 int64_t sector_num, 1290 QEMUIOVector *qiov, int nb_sectors, 1291 BlockDriverCompletionFunc *cb, 1292 void *opaque) 1293 { 1294 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, false); 1295 } 1296 1297 static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1298 int64_t sector_num, 1299 QEMUIOVector *qiov, int nb_sectors, 1300 BlockDriverCompletionFunc *cb, 1301 void *opaque) 1302 { 1303 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, true); 1304 } 1305 1306 static BlockDriverAIOCB *bdrv_qed_aio_flush(BlockDriverState *bs, 1307 BlockDriverCompletionFunc *cb, 1308 void *opaque) 1309 { 1310 return bdrv_aio_flush(bs->file, cb, opaque); 1311 } 1312 1313 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1314 { 1315 BDRVQEDState *s = bs->opaque; 1316 uint64_t old_image_size; 1317 int ret; 1318 1319 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1320 s->header.table_size)) { 1321 return -EINVAL; 1322 } 1323 1324 /* Shrinking is currently not supported */ 1325 if ((uint64_t)offset < s->header.image_size) { 1326 return -ENOTSUP; 1327 } 1328 1329 old_image_size = s->header.image_size; 1330 s->header.image_size = offset; 1331 ret = qed_write_header_sync(s); 1332 if (ret < 0) { 1333 s->header.image_size = old_image_size; 1334 } 1335 return ret; 1336 } 1337 1338 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1339 { 1340 BDRVQEDState *s = bs->opaque; 1341 return s->header.image_size; 1342 } 1343 1344 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1345 { 1346 BDRVQEDState *s = bs->opaque; 1347 1348 memset(bdi, 0, sizeof(*bdi)); 1349 bdi->cluster_size = s->header.cluster_size; 1350 return 0; 1351 } 1352 1353 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1354 const char *backing_file, 1355 const char *backing_fmt) 1356 { 1357 BDRVQEDState *s = bs->opaque; 1358 QEDHeader new_header, le_header; 1359 void *buffer; 1360 size_t buffer_len, backing_file_len; 1361 int ret; 1362 1363 /* Refuse to set backing filename if unknown compat feature bits are 1364 * active. If the image uses an unknown compat feature then we may not 1365 * know the layout of data following the header structure and cannot safely 1366 * add a new string. 1367 */ 1368 if (backing_file && (s->header.compat_features & 1369 ~QED_COMPAT_FEATURE_MASK)) { 1370 return -ENOTSUP; 1371 } 1372 1373 memcpy(&new_header, &s->header, sizeof(new_header)); 1374 1375 new_header.features &= ~(QED_F_BACKING_FILE | 1376 QED_F_BACKING_FORMAT_NO_PROBE); 1377 1378 /* Adjust feature flags */ 1379 if (backing_file) { 1380 new_header.features |= QED_F_BACKING_FILE; 1381 1382 if (qed_fmt_is_raw(backing_fmt)) { 1383 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1384 } 1385 } 1386 1387 /* Calculate new header size */ 1388 backing_file_len = 0; 1389 1390 if (backing_file) { 1391 backing_file_len = strlen(backing_file); 1392 } 1393 1394 buffer_len = sizeof(new_header); 1395 new_header.backing_filename_offset = buffer_len; 1396 new_header.backing_filename_size = backing_file_len; 1397 buffer_len += backing_file_len; 1398 1399 /* Make sure we can rewrite header without failing */ 1400 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1401 return -ENOSPC; 1402 } 1403 1404 /* Prepare new header */ 1405 buffer = g_malloc(buffer_len); 1406 1407 qed_header_cpu_to_le(&new_header, &le_header); 1408 memcpy(buffer, &le_header, sizeof(le_header)); 1409 buffer_len = sizeof(le_header); 1410 1411 if (backing_file) { 1412 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1413 buffer_len += backing_file_len; 1414 } 1415 1416 /* Write new header */ 1417 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1418 g_free(buffer); 1419 if (ret == 0) { 1420 memcpy(&s->header, &new_header, sizeof(new_header)); 1421 } 1422 return ret; 1423 } 1424 1425 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result) 1426 { 1427 BDRVQEDState *s = bs->opaque; 1428 1429 return qed_check(s, result, false); 1430 } 1431 1432 static QEMUOptionParameter qed_create_options[] = { 1433 { 1434 .name = BLOCK_OPT_SIZE, 1435 .type = OPT_SIZE, 1436 .help = "Virtual disk size (in bytes)" 1437 }, { 1438 .name = BLOCK_OPT_BACKING_FILE, 1439 .type = OPT_STRING, 1440 .help = "File name of a base image" 1441 }, { 1442 .name = BLOCK_OPT_BACKING_FMT, 1443 .type = OPT_STRING, 1444 .help = "Image format of the base image" 1445 }, { 1446 .name = BLOCK_OPT_CLUSTER_SIZE, 1447 .type = OPT_SIZE, 1448 .help = "Cluster size (in bytes)", 1449 .value = { .n = QED_DEFAULT_CLUSTER_SIZE }, 1450 }, { 1451 .name = BLOCK_OPT_TABLE_SIZE, 1452 .type = OPT_SIZE, 1453 .help = "L1/L2 table size (in clusters)" 1454 }, 1455 { /* end of list */ } 1456 }; 1457 1458 static BlockDriver bdrv_qed = { 1459 .format_name = "qed", 1460 .instance_size = sizeof(BDRVQEDState), 1461 .create_options = qed_create_options, 1462 1463 .bdrv_probe = bdrv_qed_probe, 1464 .bdrv_open = bdrv_qed_open, 1465 .bdrv_close = bdrv_qed_close, 1466 .bdrv_create = bdrv_qed_create, 1467 .bdrv_co_is_allocated = bdrv_qed_co_is_allocated, 1468 .bdrv_make_empty = bdrv_qed_make_empty, 1469 .bdrv_aio_readv = bdrv_qed_aio_readv, 1470 .bdrv_aio_writev = bdrv_qed_aio_writev, 1471 .bdrv_aio_flush = bdrv_qed_aio_flush, 1472 .bdrv_truncate = bdrv_qed_truncate, 1473 .bdrv_getlength = bdrv_qed_getlength, 1474 .bdrv_get_info = bdrv_qed_get_info, 1475 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1476 .bdrv_check = bdrv_qed_check, 1477 }; 1478 1479 static void bdrv_qed_init(void) 1480 { 1481 bdrv_register(&bdrv_qed); 1482 } 1483 1484 block_init(bdrv_qed_init); 1485