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