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 AioContext *aio_context = bdrv_get_aio_context(blockacb->bs); 25 bool finished = false; 26 27 /* Wait for the request to finish */ 28 acb->finished = &finished; 29 while (!finished) { 30 aio_poll(aio_context, true); 31 } 32 } 33 34 static const AIOCBInfo qed_aiocb_info = { 35 .aiocb_size = sizeof(QEDAIOCB), 36 .cancel = qed_aio_cancel, 37 }; 38 39 static int bdrv_qed_probe(const uint8_t *buf, int buf_size, 40 const char *filename) 41 { 42 const QEDHeader *header = (const QEDHeader *)buf; 43 44 if (buf_size < sizeof(*header)) { 45 return 0; 46 } 47 if (le32_to_cpu(header->magic) != QED_MAGIC) { 48 return 0; 49 } 50 return 100; 51 } 52 53 /** 54 * Check whether an image format is raw 55 * 56 * @fmt: Backing file format, may be NULL 57 */ 58 static bool qed_fmt_is_raw(const char *fmt) 59 { 60 return fmt && strcmp(fmt, "raw") == 0; 61 } 62 63 static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu) 64 { 65 cpu->magic = le32_to_cpu(le->magic); 66 cpu->cluster_size = le32_to_cpu(le->cluster_size); 67 cpu->table_size = le32_to_cpu(le->table_size); 68 cpu->header_size = le32_to_cpu(le->header_size); 69 cpu->features = le64_to_cpu(le->features); 70 cpu->compat_features = le64_to_cpu(le->compat_features); 71 cpu->autoclear_features = le64_to_cpu(le->autoclear_features); 72 cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset); 73 cpu->image_size = le64_to_cpu(le->image_size); 74 cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset); 75 cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size); 76 } 77 78 static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le) 79 { 80 le->magic = cpu_to_le32(cpu->magic); 81 le->cluster_size = cpu_to_le32(cpu->cluster_size); 82 le->table_size = cpu_to_le32(cpu->table_size); 83 le->header_size = cpu_to_le32(cpu->header_size); 84 le->features = cpu_to_le64(cpu->features); 85 le->compat_features = cpu_to_le64(cpu->compat_features); 86 le->autoclear_features = cpu_to_le64(cpu->autoclear_features); 87 le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset); 88 le->image_size = cpu_to_le64(cpu->image_size); 89 le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset); 90 le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size); 91 } 92 93 int qed_write_header_sync(BDRVQEDState *s) 94 { 95 QEDHeader le; 96 int ret; 97 98 qed_header_cpu_to_le(&s->header, &le); 99 ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le)); 100 if (ret != sizeof(le)) { 101 return ret; 102 } 103 return 0; 104 } 105 106 typedef struct { 107 GenericCB gencb; 108 BDRVQEDState *s; 109 struct iovec iov; 110 QEMUIOVector qiov; 111 int nsectors; 112 uint8_t *buf; 113 } QEDWriteHeaderCB; 114 115 static void qed_write_header_cb(void *opaque, int ret) 116 { 117 QEDWriteHeaderCB *write_header_cb = opaque; 118 119 qemu_vfree(write_header_cb->buf); 120 gencb_complete(write_header_cb, ret); 121 } 122 123 static void qed_write_header_read_cb(void *opaque, int ret) 124 { 125 QEDWriteHeaderCB *write_header_cb = opaque; 126 BDRVQEDState *s = write_header_cb->s; 127 128 if (ret) { 129 qed_write_header_cb(write_header_cb, ret); 130 return; 131 } 132 133 /* Update header */ 134 qed_header_cpu_to_le(&s->header, (QEDHeader *)write_header_cb->buf); 135 136 bdrv_aio_writev(s->bs->file, 0, &write_header_cb->qiov, 137 write_header_cb->nsectors, qed_write_header_cb, 138 write_header_cb); 139 } 140 141 /** 142 * Update header in-place (does not rewrite backing filename or other strings) 143 * 144 * This function only updates known header fields in-place and does not affect 145 * extra data after the QED header. 146 */ 147 static void qed_write_header(BDRVQEDState *s, BlockDriverCompletionFunc cb, 148 void *opaque) 149 { 150 /* We must write full sectors for O_DIRECT but cannot necessarily generate 151 * the data following the header if an unrecognized compat feature is 152 * active. Therefore, first read the sectors containing the header, update 153 * them, and write back. 154 */ 155 156 int nsectors = (sizeof(QEDHeader) + BDRV_SECTOR_SIZE - 1) / 157 BDRV_SECTOR_SIZE; 158 size_t len = nsectors * BDRV_SECTOR_SIZE; 159 QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb), 160 cb, opaque); 161 162 write_header_cb->s = s; 163 write_header_cb->nsectors = nsectors; 164 write_header_cb->buf = qemu_blockalign(s->bs, len); 165 write_header_cb->iov.iov_base = write_header_cb->buf; 166 write_header_cb->iov.iov_len = len; 167 qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1); 168 169 bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors, 170 qed_write_header_read_cb, write_header_cb); 171 } 172 173 static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size) 174 { 175 uint64_t table_entries; 176 uint64_t l2_size; 177 178 table_entries = (table_size * cluster_size) / sizeof(uint64_t); 179 l2_size = table_entries * cluster_size; 180 181 return l2_size * table_entries; 182 } 183 184 static bool qed_is_cluster_size_valid(uint32_t cluster_size) 185 { 186 if (cluster_size < QED_MIN_CLUSTER_SIZE || 187 cluster_size > QED_MAX_CLUSTER_SIZE) { 188 return false; 189 } 190 if (cluster_size & (cluster_size - 1)) { 191 return false; /* not power of 2 */ 192 } 193 return true; 194 } 195 196 static bool qed_is_table_size_valid(uint32_t table_size) 197 { 198 if (table_size < QED_MIN_TABLE_SIZE || 199 table_size > QED_MAX_TABLE_SIZE) { 200 return false; 201 } 202 if (table_size & (table_size - 1)) { 203 return false; /* not power of 2 */ 204 } 205 return true; 206 } 207 208 static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size, 209 uint32_t table_size) 210 { 211 if (image_size % BDRV_SECTOR_SIZE != 0) { 212 return false; /* not multiple of sector size */ 213 } 214 if (image_size > qed_max_image_size(cluster_size, table_size)) { 215 return false; /* image is too large */ 216 } 217 return true; 218 } 219 220 /** 221 * Read a string of known length from the image file 222 * 223 * @file: Image file 224 * @offset: File offset to start of string, in bytes 225 * @n: String length in bytes 226 * @buf: Destination buffer 227 * @buflen: Destination buffer length in bytes 228 * @ret: 0 on success, -errno on failure 229 * 230 * The string is NUL-terminated. 231 */ 232 static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n, 233 char *buf, size_t buflen) 234 { 235 int ret; 236 if (n >= buflen) { 237 return -EINVAL; 238 } 239 ret = bdrv_pread(file, offset, buf, n); 240 if (ret < 0) { 241 return ret; 242 } 243 buf[n] = '\0'; 244 return 0; 245 } 246 247 /** 248 * Allocate new clusters 249 * 250 * @s: QED state 251 * @n: Number of contiguous clusters to allocate 252 * @ret: Offset of first allocated cluster 253 * 254 * This function only produces the offset where the new clusters should be 255 * written. It updates BDRVQEDState but does not make any changes to the image 256 * file. 257 */ 258 static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n) 259 { 260 uint64_t offset = s->file_size; 261 s->file_size += n * s->header.cluster_size; 262 return offset; 263 } 264 265 QEDTable *qed_alloc_table(BDRVQEDState *s) 266 { 267 /* Honor O_DIRECT memory alignment requirements */ 268 return qemu_blockalign(s->bs, 269 s->header.cluster_size * s->header.table_size); 270 } 271 272 /** 273 * Allocate a new zeroed L2 table 274 */ 275 static CachedL2Table *qed_new_l2_table(BDRVQEDState *s) 276 { 277 CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache); 278 279 l2_table->table = qed_alloc_table(s); 280 l2_table->offset = qed_alloc_clusters(s, s->header.table_size); 281 282 memset(l2_table->table->offsets, 0, 283 s->header.cluster_size * s->header.table_size); 284 return l2_table; 285 } 286 287 static void qed_aio_next_io(void *opaque, int ret); 288 289 static void qed_plug_allocating_write_reqs(BDRVQEDState *s) 290 { 291 assert(!s->allocating_write_reqs_plugged); 292 293 s->allocating_write_reqs_plugged = true; 294 } 295 296 static void qed_unplug_allocating_write_reqs(BDRVQEDState *s) 297 { 298 QEDAIOCB *acb; 299 300 assert(s->allocating_write_reqs_plugged); 301 302 s->allocating_write_reqs_plugged = false; 303 304 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 305 if (acb) { 306 qed_aio_next_io(acb, 0); 307 } 308 } 309 310 static void qed_finish_clear_need_check(void *opaque, int ret) 311 { 312 /* Do nothing */ 313 } 314 315 static void qed_flush_after_clear_need_check(void *opaque, int ret) 316 { 317 BDRVQEDState *s = opaque; 318 319 bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s); 320 321 /* No need to wait until flush completes */ 322 qed_unplug_allocating_write_reqs(s); 323 } 324 325 static void qed_clear_need_check(void *opaque, int ret) 326 { 327 BDRVQEDState *s = opaque; 328 329 if (ret) { 330 qed_unplug_allocating_write_reqs(s); 331 return; 332 } 333 334 s->header.features &= ~QED_F_NEED_CHECK; 335 qed_write_header(s, qed_flush_after_clear_need_check, s); 336 } 337 338 static void qed_need_check_timer_cb(void *opaque) 339 { 340 BDRVQEDState *s = opaque; 341 342 /* The timer should only fire when allocating writes have drained */ 343 assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs)); 344 345 trace_qed_need_check_timer_cb(s); 346 347 qed_plug_allocating_write_reqs(s); 348 349 /* Ensure writes are on disk before clearing flag */ 350 bdrv_aio_flush(s->bs, qed_clear_need_check, s); 351 } 352 353 static void qed_start_need_check_timer(BDRVQEDState *s) 354 { 355 trace_qed_start_need_check_timer(s); 356 357 /* Use QEMU_CLOCK_VIRTUAL so we don't alter the image file while suspended for 358 * migration. 359 */ 360 timer_mod(s->need_check_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 361 get_ticks_per_sec() * QED_NEED_CHECK_TIMEOUT); 362 } 363 364 /* It's okay to call this multiple times or when no timer is started */ 365 static void qed_cancel_need_check_timer(BDRVQEDState *s) 366 { 367 trace_qed_cancel_need_check_timer(s); 368 timer_del(s->need_check_timer); 369 } 370 371 static void bdrv_qed_rebind(BlockDriverState *bs) 372 { 373 BDRVQEDState *s = bs->opaque; 374 s->bs = bs; 375 } 376 377 static void bdrv_qed_detach_aio_context(BlockDriverState *bs) 378 { 379 BDRVQEDState *s = bs->opaque; 380 381 qed_cancel_need_check_timer(s); 382 timer_free(s->need_check_timer); 383 } 384 385 static void bdrv_qed_attach_aio_context(BlockDriverState *bs, 386 AioContext *new_context) 387 { 388 BDRVQEDState *s = bs->opaque; 389 390 s->need_check_timer = aio_timer_new(new_context, 391 QEMU_CLOCK_VIRTUAL, SCALE_NS, 392 qed_need_check_timer_cb, s); 393 if (s->header.features & QED_F_NEED_CHECK) { 394 qed_start_need_check_timer(s); 395 } 396 } 397 398 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, 399 Error **errp) 400 { 401 BDRVQEDState *s = bs->opaque; 402 QEDHeader le_header; 403 int64_t file_size; 404 int ret; 405 406 s->bs = bs; 407 QSIMPLEQ_INIT(&s->allocating_write_reqs); 408 409 ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); 410 if (ret < 0) { 411 return ret; 412 } 413 qed_header_le_to_cpu(&le_header, &s->header); 414 415 if (s->header.magic != QED_MAGIC) { 416 error_setg(errp, "Image not in QED format"); 417 return -EINVAL; 418 } 419 if (s->header.features & ~QED_FEATURE_MASK) { 420 /* image uses unsupported feature bits */ 421 char buf[64]; 422 snprintf(buf, sizeof(buf), "%" PRIx64, 423 s->header.features & ~QED_FEATURE_MASK); 424 error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 425 bs->device_name, "QED", buf); 426 return -ENOTSUP; 427 } 428 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 429 return -EINVAL; 430 } 431 432 /* Round down file size to the last cluster */ 433 file_size = bdrv_getlength(bs->file); 434 if (file_size < 0) { 435 return file_size; 436 } 437 s->file_size = qed_start_of_cluster(s, file_size); 438 439 if (!qed_is_table_size_valid(s->header.table_size)) { 440 return -EINVAL; 441 } 442 if (!qed_is_image_size_valid(s->header.image_size, 443 s->header.cluster_size, 444 s->header.table_size)) { 445 return -EINVAL; 446 } 447 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 448 return -EINVAL; 449 } 450 451 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 452 sizeof(uint64_t); 453 s->l2_shift = ffs(s->header.cluster_size) - 1; 454 s->l2_mask = s->table_nelems - 1; 455 s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1; 456 457 if ((s->header.features & QED_F_BACKING_FILE)) { 458 if ((uint64_t)s->header.backing_filename_offset + 459 s->header.backing_filename_size > 460 s->header.cluster_size * s->header.header_size) { 461 return -EINVAL; 462 } 463 464 ret = qed_read_string(bs->file, s->header.backing_filename_offset, 465 s->header.backing_filename_size, bs->backing_file, 466 sizeof(bs->backing_file)); 467 if (ret < 0) { 468 return ret; 469 } 470 471 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 472 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 473 } 474 } 475 476 /* Reset unknown autoclear feature bits. This is a backwards 477 * compatibility mechanism that allows images to be opened by older 478 * programs, which "knock out" unknown feature bits. When an image is 479 * opened by a newer program again it can detect that the autoclear 480 * feature is no longer valid. 481 */ 482 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 483 !bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) { 484 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 485 486 ret = qed_write_header_sync(s); 487 if (ret) { 488 return ret; 489 } 490 491 /* From here on only known autoclear feature bits are valid */ 492 bdrv_flush(bs->file); 493 } 494 495 s->l1_table = qed_alloc_table(s); 496 qed_init_l2_cache(&s->l2_cache); 497 498 ret = qed_read_l1_table_sync(s); 499 if (ret) { 500 goto out; 501 } 502 503 /* If image was not closed cleanly, check consistency */ 504 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { 505 /* Read-only images cannot be fixed. There is no risk of corruption 506 * since write operations are not possible. Therefore, allow 507 * potentially inconsistent images to be opened read-only. This can 508 * aid data recovery from an otherwise inconsistent image. 509 */ 510 if (!bdrv_is_read_only(bs->file) && 511 !(flags & BDRV_O_INCOMING)) { 512 BdrvCheckResult result = {0}; 513 514 ret = qed_check(s, &result, true); 515 if (ret) { 516 goto out; 517 } 518 } 519 } 520 521 bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); 522 523 out: 524 if (ret) { 525 qed_free_l2_cache(&s->l2_cache); 526 qemu_vfree(s->l1_table); 527 } 528 return ret; 529 } 530 531 static int bdrv_qed_refresh_limits(BlockDriverState *bs) 532 { 533 BDRVQEDState *s = bs->opaque; 534 535 bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS; 536 537 return 0; 538 } 539 540 /* We have nothing to do for QED reopen, stubs just return 541 * success */ 542 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 543 BlockReopenQueue *queue, Error **errp) 544 { 545 return 0; 546 } 547 548 static void bdrv_qed_close(BlockDriverState *bs) 549 { 550 BDRVQEDState *s = bs->opaque; 551 552 bdrv_qed_detach_aio_context(bs); 553 554 /* Ensure writes reach stable storage */ 555 bdrv_flush(bs->file); 556 557 /* Clean shutdown, no check required on next open */ 558 if (s->header.features & QED_F_NEED_CHECK) { 559 s->header.features &= ~QED_F_NEED_CHECK; 560 qed_write_header_sync(s); 561 } 562 563 qed_free_l2_cache(&s->l2_cache); 564 qemu_vfree(s->l1_table); 565 } 566 567 static int qed_create(const char *filename, uint32_t cluster_size, 568 uint64_t image_size, uint32_t table_size, 569 const char *backing_file, const char *backing_fmt, 570 QemuOpts *opts, Error **errp) 571 { 572 QEDHeader header = { 573 .magic = QED_MAGIC, 574 .cluster_size = cluster_size, 575 .table_size = table_size, 576 .header_size = 1, 577 .features = 0, 578 .compat_features = 0, 579 .l1_table_offset = cluster_size, 580 .image_size = image_size, 581 }; 582 QEDHeader le_header; 583 uint8_t *l1_table = NULL; 584 size_t l1_size = header.cluster_size * header.table_size; 585 Error *local_err = NULL; 586 int ret = 0; 587 BlockDriverState *bs; 588 589 ret = bdrv_create_file(filename, opts, &local_err); 590 if (ret < 0) { 591 error_propagate(errp, local_err); 592 return ret; 593 } 594 595 bs = NULL; 596 ret = bdrv_open(&bs, filename, NULL, NULL, 597 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, NULL, 598 &local_err); 599 if (ret < 0) { 600 error_propagate(errp, local_err); 601 return ret; 602 } 603 604 /* File must start empty and grow, check truncate is supported */ 605 ret = bdrv_truncate(bs, 0); 606 if (ret < 0) { 607 goto out; 608 } 609 610 if (backing_file) { 611 header.features |= QED_F_BACKING_FILE; 612 header.backing_filename_offset = sizeof(le_header); 613 header.backing_filename_size = strlen(backing_file); 614 615 if (qed_fmt_is_raw(backing_fmt)) { 616 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 617 } 618 } 619 620 qed_header_cpu_to_le(&header, &le_header); 621 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); 622 if (ret < 0) { 623 goto out; 624 } 625 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file, 626 header.backing_filename_size); 627 if (ret < 0) { 628 goto out; 629 } 630 631 l1_table = g_malloc0(l1_size); 632 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size); 633 if (ret < 0) { 634 goto out; 635 } 636 637 ret = 0; /* success */ 638 out: 639 g_free(l1_table); 640 bdrv_unref(bs); 641 return ret; 642 } 643 644 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 645 { 646 uint64_t image_size = 0; 647 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 648 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 649 char *backing_file = NULL; 650 char *backing_fmt = NULL; 651 int ret; 652 653 image_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 654 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 655 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 656 cluster_size = qemu_opt_get_size_del(opts, 657 BLOCK_OPT_CLUSTER_SIZE, 658 QED_DEFAULT_CLUSTER_SIZE); 659 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 660 QED_DEFAULT_TABLE_SIZE); 661 662 if (!qed_is_cluster_size_valid(cluster_size)) { 663 error_setg(errp, "QED cluster size must be within range [%u, %u] " 664 "and power of 2", 665 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 666 ret = -EINVAL; 667 goto finish; 668 } 669 if (!qed_is_table_size_valid(table_size)) { 670 error_setg(errp, "QED table size must be within range [%u, %u] " 671 "and power of 2", 672 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 673 ret = -EINVAL; 674 goto finish; 675 } 676 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 677 error_setg(errp, "QED image size must be a non-zero multiple of " 678 "cluster size and less than %" PRIu64 " bytes", 679 qed_max_image_size(cluster_size, table_size)); 680 ret = -EINVAL; 681 goto finish; 682 } 683 684 ret = qed_create(filename, cluster_size, image_size, table_size, 685 backing_file, backing_fmt, opts, errp); 686 687 finish: 688 g_free(backing_file); 689 g_free(backing_fmt); 690 return ret; 691 } 692 693 typedef struct { 694 BlockDriverState *bs; 695 Coroutine *co; 696 uint64_t pos; 697 int64_t status; 698 int *pnum; 699 } QEDIsAllocatedCB; 700 701 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 702 { 703 QEDIsAllocatedCB *cb = opaque; 704 BDRVQEDState *s = cb->bs->opaque; 705 *cb->pnum = len / BDRV_SECTOR_SIZE; 706 switch (ret) { 707 case QED_CLUSTER_FOUND: 708 offset |= qed_offset_into_cluster(s, cb->pos); 709 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 710 break; 711 case QED_CLUSTER_ZERO: 712 cb->status = BDRV_BLOCK_ZERO; 713 break; 714 case QED_CLUSTER_L2: 715 case QED_CLUSTER_L1: 716 cb->status = 0; 717 break; 718 default: 719 assert(ret < 0); 720 cb->status = ret; 721 break; 722 } 723 724 if (cb->co) { 725 qemu_coroutine_enter(cb->co, NULL); 726 } 727 } 728 729 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 730 int64_t sector_num, 731 int nb_sectors, int *pnum) 732 { 733 BDRVQEDState *s = bs->opaque; 734 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 735 QEDIsAllocatedCB cb = { 736 .bs = bs, 737 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 738 .status = BDRV_BLOCK_OFFSET_MASK, 739 .pnum = pnum, 740 }; 741 QEDRequest request = { .l2_table = NULL }; 742 743 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 744 745 /* Now sleep if the callback wasn't invoked immediately */ 746 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 747 cb.co = qemu_coroutine_self(); 748 qemu_coroutine_yield(); 749 } 750 751 qed_unref_l2_cache_entry(request.l2_table); 752 753 return cb.status; 754 } 755 756 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 757 { 758 return acb->common.bs->opaque; 759 } 760 761 /** 762 * Read from the backing file or zero-fill if no backing file 763 * 764 * @s: QED state 765 * @pos: Byte position in device 766 * @qiov: Destination I/O vector 767 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 768 * @cb: Completion function 769 * @opaque: User data for completion function 770 * 771 * This function reads qiov->size bytes starting at pos from the backing file. 772 * If there is no backing file then zeroes are read. 773 */ 774 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 775 QEMUIOVector *qiov, 776 QEMUIOVector **backing_qiov, 777 BlockDriverCompletionFunc *cb, void *opaque) 778 { 779 uint64_t backing_length = 0; 780 size_t size; 781 782 /* If there is a backing file, get its length. Treat the absence of a 783 * backing file like a zero length backing file. 784 */ 785 if (s->bs->backing_hd) { 786 int64_t l = bdrv_getlength(s->bs->backing_hd); 787 if (l < 0) { 788 cb(opaque, l); 789 return; 790 } 791 backing_length = l; 792 } 793 794 /* Zero all sectors if reading beyond the end of the backing file */ 795 if (pos >= backing_length || 796 pos + qiov->size > backing_length) { 797 qemu_iovec_memset(qiov, 0, 0, qiov->size); 798 } 799 800 /* Complete now if there are no backing file sectors to read */ 801 if (pos >= backing_length) { 802 cb(opaque, 0); 803 return; 804 } 805 806 /* If the read straddles the end of the backing file, shorten it */ 807 size = MIN((uint64_t)backing_length - pos, qiov->size); 808 809 assert(*backing_qiov == NULL); 810 *backing_qiov = g_new(QEMUIOVector, 1); 811 qemu_iovec_init(*backing_qiov, qiov->niov); 812 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 813 814 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 815 bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE, 816 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 817 } 818 819 typedef struct { 820 GenericCB gencb; 821 BDRVQEDState *s; 822 QEMUIOVector qiov; 823 QEMUIOVector *backing_qiov; 824 struct iovec iov; 825 uint64_t offset; 826 } CopyFromBackingFileCB; 827 828 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 829 { 830 CopyFromBackingFileCB *copy_cb = opaque; 831 qemu_vfree(copy_cb->iov.iov_base); 832 gencb_complete(©_cb->gencb, ret); 833 } 834 835 static void qed_copy_from_backing_file_write(void *opaque, int ret) 836 { 837 CopyFromBackingFileCB *copy_cb = opaque; 838 BDRVQEDState *s = copy_cb->s; 839 840 if (copy_cb->backing_qiov) { 841 qemu_iovec_destroy(copy_cb->backing_qiov); 842 g_free(copy_cb->backing_qiov); 843 copy_cb->backing_qiov = NULL; 844 } 845 846 if (ret) { 847 qed_copy_from_backing_file_cb(copy_cb, ret); 848 return; 849 } 850 851 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 852 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 853 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 854 qed_copy_from_backing_file_cb, copy_cb); 855 } 856 857 /** 858 * Copy data from backing file into the image 859 * 860 * @s: QED state 861 * @pos: Byte position in device 862 * @len: Number of bytes 863 * @offset: Byte offset in image file 864 * @cb: Completion function 865 * @opaque: User data for completion function 866 */ 867 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 868 uint64_t len, uint64_t offset, 869 BlockDriverCompletionFunc *cb, 870 void *opaque) 871 { 872 CopyFromBackingFileCB *copy_cb; 873 874 /* Skip copy entirely if there is no work to do */ 875 if (len == 0) { 876 cb(opaque, 0); 877 return; 878 } 879 880 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 881 copy_cb->s = s; 882 copy_cb->offset = offset; 883 copy_cb->backing_qiov = NULL; 884 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 885 copy_cb->iov.iov_len = len; 886 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 887 888 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 889 qed_copy_from_backing_file_write, copy_cb); 890 } 891 892 /** 893 * Link one or more contiguous clusters into a table 894 * 895 * @s: QED state 896 * @table: L2 table 897 * @index: First cluster index 898 * @n: Number of contiguous clusters 899 * @cluster: First cluster offset 900 * 901 * The cluster offset may be an allocated byte offset in the image file, the 902 * zero cluster marker, or the unallocated cluster marker. 903 */ 904 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 905 unsigned int n, uint64_t cluster) 906 { 907 int i; 908 for (i = index; i < index + n; i++) { 909 table->offsets[i] = cluster; 910 if (!qed_offset_is_unalloc_cluster(cluster) && 911 !qed_offset_is_zero_cluster(cluster)) { 912 cluster += s->header.cluster_size; 913 } 914 } 915 } 916 917 static void qed_aio_complete_bh(void *opaque) 918 { 919 QEDAIOCB *acb = opaque; 920 BlockDriverCompletionFunc *cb = acb->common.cb; 921 void *user_opaque = acb->common.opaque; 922 int ret = acb->bh_ret; 923 bool *finished = acb->finished; 924 925 qemu_bh_delete(acb->bh); 926 qemu_aio_release(acb); 927 928 /* Invoke callback */ 929 cb(user_opaque, ret); 930 931 /* Signal cancel completion */ 932 if (finished) { 933 *finished = true; 934 } 935 } 936 937 static void qed_aio_complete(QEDAIOCB *acb, int ret) 938 { 939 BDRVQEDState *s = acb_to_s(acb); 940 941 trace_qed_aio_complete(s, acb, ret); 942 943 /* Free resources */ 944 qemu_iovec_destroy(&acb->cur_qiov); 945 qed_unref_l2_cache_entry(acb->request.l2_table); 946 947 /* Free the buffer we may have allocated for zero writes */ 948 if (acb->flags & QED_AIOCB_ZERO) { 949 qemu_vfree(acb->qiov->iov[0].iov_base); 950 acb->qiov->iov[0].iov_base = NULL; 951 } 952 953 /* Arrange for a bh to invoke the completion function */ 954 acb->bh_ret = ret; 955 acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs), 956 qed_aio_complete_bh, acb); 957 qemu_bh_schedule(acb->bh); 958 959 /* Start next allocating write request waiting behind this one. Note that 960 * requests enqueue themselves when they first hit an unallocated cluster 961 * but they wait until the entire request is finished before waking up the 962 * next request in the queue. This ensures that we don't cycle through 963 * requests multiple times but rather finish one at a time completely. 964 */ 965 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 966 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 967 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 968 if (acb) { 969 qed_aio_next_io(acb, 0); 970 } else if (s->header.features & QED_F_NEED_CHECK) { 971 qed_start_need_check_timer(s); 972 } 973 } 974 } 975 976 /** 977 * Commit the current L2 table to the cache 978 */ 979 static void qed_commit_l2_update(void *opaque, int ret) 980 { 981 QEDAIOCB *acb = opaque; 982 BDRVQEDState *s = acb_to_s(acb); 983 CachedL2Table *l2_table = acb->request.l2_table; 984 uint64_t l2_offset = l2_table->offset; 985 986 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 987 988 /* This is guaranteed to succeed because we just committed the entry to the 989 * cache. 990 */ 991 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 992 assert(acb->request.l2_table != NULL); 993 994 qed_aio_next_io(opaque, ret); 995 } 996 997 /** 998 * Update L1 table with new L2 table offset and write it out 999 */ 1000 static void qed_aio_write_l1_update(void *opaque, int ret) 1001 { 1002 QEDAIOCB *acb = opaque; 1003 BDRVQEDState *s = acb_to_s(acb); 1004 int index; 1005 1006 if (ret) { 1007 qed_aio_complete(acb, ret); 1008 return; 1009 } 1010 1011 index = qed_l1_index(s, acb->cur_pos); 1012 s->l1_table->offsets[index] = acb->request.l2_table->offset; 1013 1014 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 1015 } 1016 1017 /** 1018 * Update L2 table with new cluster offsets and write them out 1019 */ 1020 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 1021 { 1022 BDRVQEDState *s = acb_to_s(acb); 1023 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1024 int index; 1025 1026 if (ret) { 1027 goto err; 1028 } 1029 1030 if (need_alloc) { 1031 qed_unref_l2_cache_entry(acb->request.l2_table); 1032 acb->request.l2_table = qed_new_l2_table(s); 1033 } 1034 1035 index = qed_l2_index(s, acb->cur_pos); 1036 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1037 offset); 1038 1039 if (need_alloc) { 1040 /* Write out the whole new L2 table */ 1041 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1042 qed_aio_write_l1_update, acb); 1043 } else { 1044 /* Write out only the updated part of the L2 table */ 1045 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1046 qed_aio_next_io, acb); 1047 } 1048 return; 1049 1050 err: 1051 qed_aio_complete(acb, ret); 1052 } 1053 1054 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1055 { 1056 QEDAIOCB *acb = opaque; 1057 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1058 } 1059 1060 /** 1061 * Flush new data clusters before updating the L2 table 1062 * 1063 * This flush is necessary when a backing file is in use. A crash during an 1064 * allocating write could result in empty clusters in the image. If the write 1065 * only touched a subregion of the cluster, then backing image sectors have 1066 * been lost in the untouched region. The solution is to flush after writing a 1067 * new data cluster and before updating the L2 table. 1068 */ 1069 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1070 { 1071 QEDAIOCB *acb = opaque; 1072 BDRVQEDState *s = acb_to_s(acb); 1073 1074 if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update_cb, opaque)) { 1075 qed_aio_complete(acb, -EIO); 1076 } 1077 } 1078 1079 /** 1080 * Write data to the image file 1081 */ 1082 static void qed_aio_write_main(void *opaque, int ret) 1083 { 1084 QEDAIOCB *acb = opaque; 1085 BDRVQEDState *s = acb_to_s(acb); 1086 uint64_t offset = acb->cur_cluster + 1087 qed_offset_into_cluster(s, acb->cur_pos); 1088 BlockDriverCompletionFunc *next_fn; 1089 1090 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1091 1092 if (ret) { 1093 qed_aio_complete(acb, ret); 1094 return; 1095 } 1096 1097 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1098 next_fn = qed_aio_next_io; 1099 } else { 1100 if (s->bs->backing_hd) { 1101 next_fn = qed_aio_write_flush_before_l2_update; 1102 } else { 1103 next_fn = qed_aio_write_l2_update_cb; 1104 } 1105 } 1106 1107 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1108 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1109 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1110 next_fn, acb); 1111 } 1112 1113 /** 1114 * Populate back untouched region of new data cluster 1115 */ 1116 static void qed_aio_write_postfill(void *opaque, int ret) 1117 { 1118 QEDAIOCB *acb = opaque; 1119 BDRVQEDState *s = acb_to_s(acb); 1120 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1121 uint64_t len = 1122 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1123 uint64_t offset = acb->cur_cluster + 1124 qed_offset_into_cluster(s, acb->cur_pos) + 1125 acb->cur_qiov.size; 1126 1127 if (ret) { 1128 qed_aio_complete(acb, ret); 1129 return; 1130 } 1131 1132 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1133 qed_copy_from_backing_file(s, start, len, offset, 1134 qed_aio_write_main, acb); 1135 } 1136 1137 /** 1138 * Populate front untouched region of new data cluster 1139 */ 1140 static void qed_aio_write_prefill(void *opaque, int ret) 1141 { 1142 QEDAIOCB *acb = opaque; 1143 BDRVQEDState *s = acb_to_s(acb); 1144 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1145 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1146 1147 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1148 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1149 qed_aio_write_postfill, acb); 1150 } 1151 1152 /** 1153 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1154 */ 1155 static bool qed_should_set_need_check(BDRVQEDState *s) 1156 { 1157 /* The flush before L2 update path ensures consistency */ 1158 if (s->bs->backing_hd) { 1159 return false; 1160 } 1161 1162 return !(s->header.features & QED_F_NEED_CHECK); 1163 } 1164 1165 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1166 { 1167 QEDAIOCB *acb = opaque; 1168 1169 if (ret) { 1170 qed_aio_complete(acb, ret); 1171 return; 1172 } 1173 1174 qed_aio_write_l2_update(acb, 0, 1); 1175 } 1176 1177 /** 1178 * Write new data cluster 1179 * 1180 * @acb: Write request 1181 * @len: Length in bytes 1182 * 1183 * This path is taken when writing to previously unallocated clusters. 1184 */ 1185 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1186 { 1187 BDRVQEDState *s = acb_to_s(acb); 1188 BlockDriverCompletionFunc *cb; 1189 1190 /* Cancel timer when the first allocating request comes in */ 1191 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1192 qed_cancel_need_check_timer(s); 1193 } 1194 1195 /* Freeze this request if another allocating write is in progress */ 1196 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1197 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1198 } 1199 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1200 s->allocating_write_reqs_plugged) { 1201 return; /* wait for existing request to finish */ 1202 } 1203 1204 acb->cur_nclusters = qed_bytes_to_clusters(s, 1205 qed_offset_into_cluster(s, acb->cur_pos) + len); 1206 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1207 1208 if (acb->flags & QED_AIOCB_ZERO) { 1209 /* Skip ahead if the clusters are already zero */ 1210 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1211 qed_aio_next_io(acb, 0); 1212 return; 1213 } 1214 1215 cb = qed_aio_write_zero_cluster; 1216 } else { 1217 cb = qed_aio_write_prefill; 1218 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1219 } 1220 1221 if (qed_should_set_need_check(s)) { 1222 s->header.features |= QED_F_NEED_CHECK; 1223 qed_write_header(s, cb, acb); 1224 } else { 1225 cb(acb, 0); 1226 } 1227 } 1228 1229 /** 1230 * Write data cluster in place 1231 * 1232 * @acb: Write request 1233 * @offset: Cluster offset in bytes 1234 * @len: Length in bytes 1235 * 1236 * This path is taken when writing to already allocated clusters. 1237 */ 1238 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1239 { 1240 /* Allocate buffer for zero writes */ 1241 if (acb->flags & QED_AIOCB_ZERO) { 1242 struct iovec *iov = acb->qiov->iov; 1243 1244 if (!iov->iov_base) { 1245 iov->iov_base = qemu_blockalign(acb->common.bs, iov->iov_len); 1246 memset(iov->iov_base, 0, iov->iov_len); 1247 } 1248 } 1249 1250 /* Calculate the I/O vector */ 1251 acb->cur_cluster = offset; 1252 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1253 1254 /* Do the actual write */ 1255 qed_aio_write_main(acb, 0); 1256 } 1257 1258 /** 1259 * Write data cluster 1260 * 1261 * @opaque: Write request 1262 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1263 * or -errno 1264 * @offset: Cluster offset in bytes 1265 * @len: Length in bytes 1266 * 1267 * Callback from qed_find_cluster(). 1268 */ 1269 static void qed_aio_write_data(void *opaque, int ret, 1270 uint64_t offset, size_t len) 1271 { 1272 QEDAIOCB *acb = opaque; 1273 1274 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1275 1276 acb->find_cluster_ret = ret; 1277 1278 switch (ret) { 1279 case QED_CLUSTER_FOUND: 1280 qed_aio_write_inplace(acb, offset, len); 1281 break; 1282 1283 case QED_CLUSTER_L2: 1284 case QED_CLUSTER_L1: 1285 case QED_CLUSTER_ZERO: 1286 qed_aio_write_alloc(acb, len); 1287 break; 1288 1289 default: 1290 qed_aio_complete(acb, ret); 1291 break; 1292 } 1293 } 1294 1295 /** 1296 * Read data cluster 1297 * 1298 * @opaque: Read request 1299 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1300 * or -errno 1301 * @offset: Cluster offset in bytes 1302 * @len: Length in bytes 1303 * 1304 * Callback from qed_find_cluster(). 1305 */ 1306 static void qed_aio_read_data(void *opaque, int ret, 1307 uint64_t offset, size_t len) 1308 { 1309 QEDAIOCB *acb = opaque; 1310 BDRVQEDState *s = acb_to_s(acb); 1311 BlockDriverState *bs = acb->common.bs; 1312 1313 /* Adjust offset into cluster */ 1314 offset += qed_offset_into_cluster(s, acb->cur_pos); 1315 1316 trace_qed_aio_read_data(s, acb, ret, offset, len); 1317 1318 if (ret < 0) { 1319 goto err; 1320 } 1321 1322 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1323 1324 /* Handle zero cluster and backing file reads */ 1325 if (ret == QED_CLUSTER_ZERO) { 1326 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1327 qed_aio_next_io(acb, 0); 1328 return; 1329 } else if (ret != QED_CLUSTER_FOUND) { 1330 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1331 &acb->backing_qiov, qed_aio_next_io, acb); 1332 return; 1333 } 1334 1335 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1336 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1337 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1338 qed_aio_next_io, acb); 1339 return; 1340 1341 err: 1342 qed_aio_complete(acb, ret); 1343 } 1344 1345 /** 1346 * Begin next I/O or complete the request 1347 */ 1348 static void qed_aio_next_io(void *opaque, int ret) 1349 { 1350 QEDAIOCB *acb = opaque; 1351 BDRVQEDState *s = acb_to_s(acb); 1352 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1353 qed_aio_write_data : qed_aio_read_data; 1354 1355 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1356 1357 if (acb->backing_qiov) { 1358 qemu_iovec_destroy(acb->backing_qiov); 1359 g_free(acb->backing_qiov); 1360 acb->backing_qiov = NULL; 1361 } 1362 1363 /* Handle I/O error */ 1364 if (ret) { 1365 qed_aio_complete(acb, ret); 1366 return; 1367 } 1368 1369 acb->qiov_offset += acb->cur_qiov.size; 1370 acb->cur_pos += acb->cur_qiov.size; 1371 qemu_iovec_reset(&acb->cur_qiov); 1372 1373 /* Complete request */ 1374 if (acb->cur_pos >= acb->end_pos) { 1375 qed_aio_complete(acb, 0); 1376 return; 1377 } 1378 1379 /* Find next cluster and start I/O */ 1380 qed_find_cluster(s, &acb->request, 1381 acb->cur_pos, acb->end_pos - acb->cur_pos, 1382 io_fn, acb); 1383 } 1384 1385 static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs, 1386 int64_t sector_num, 1387 QEMUIOVector *qiov, int nb_sectors, 1388 BlockDriverCompletionFunc *cb, 1389 void *opaque, int flags) 1390 { 1391 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1392 1393 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1394 opaque, flags); 1395 1396 acb->flags = flags; 1397 acb->finished = NULL; 1398 acb->qiov = qiov; 1399 acb->qiov_offset = 0; 1400 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1401 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1402 acb->backing_qiov = NULL; 1403 acb->request.l2_table = NULL; 1404 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1405 1406 /* Start request */ 1407 qed_aio_next_io(acb, 0); 1408 return &acb->common; 1409 } 1410 1411 static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1412 int64_t sector_num, 1413 QEMUIOVector *qiov, int nb_sectors, 1414 BlockDriverCompletionFunc *cb, 1415 void *opaque) 1416 { 1417 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1418 } 1419 1420 static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1421 int64_t sector_num, 1422 QEMUIOVector *qiov, int nb_sectors, 1423 BlockDriverCompletionFunc *cb, 1424 void *opaque) 1425 { 1426 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1427 opaque, QED_AIOCB_WRITE); 1428 } 1429 1430 typedef struct { 1431 Coroutine *co; 1432 int ret; 1433 bool done; 1434 } QEDWriteZeroesCB; 1435 1436 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret) 1437 { 1438 QEDWriteZeroesCB *cb = opaque; 1439 1440 cb->done = true; 1441 cb->ret = ret; 1442 if (cb->co) { 1443 qemu_coroutine_enter(cb->co, NULL); 1444 } 1445 } 1446 1447 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs, 1448 int64_t sector_num, 1449 int nb_sectors, 1450 BdrvRequestFlags flags) 1451 { 1452 BlockDriverAIOCB *blockacb; 1453 BDRVQEDState *s = bs->opaque; 1454 QEDWriteZeroesCB cb = { .done = false }; 1455 QEMUIOVector qiov; 1456 struct iovec iov; 1457 1458 /* Refuse if there are untouched backing file sectors */ 1459 if (bs->backing_hd) { 1460 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) { 1461 return -ENOTSUP; 1462 } 1463 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) { 1464 return -ENOTSUP; 1465 } 1466 } 1467 1468 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1469 * then it will be allocated during request processing. 1470 */ 1471 iov.iov_base = NULL, 1472 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE, 1473 1474 qemu_iovec_init_external(&qiov, &iov, 1); 1475 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors, 1476 qed_co_write_zeroes_cb, &cb, 1477 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1478 if (!blockacb) { 1479 return -EIO; 1480 } 1481 if (!cb.done) { 1482 cb.co = qemu_coroutine_self(); 1483 qemu_coroutine_yield(); 1484 } 1485 assert(cb.done); 1486 return cb.ret; 1487 } 1488 1489 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1490 { 1491 BDRVQEDState *s = bs->opaque; 1492 uint64_t old_image_size; 1493 int ret; 1494 1495 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1496 s->header.table_size)) { 1497 return -EINVAL; 1498 } 1499 1500 /* Shrinking is currently not supported */ 1501 if ((uint64_t)offset < s->header.image_size) { 1502 return -ENOTSUP; 1503 } 1504 1505 old_image_size = s->header.image_size; 1506 s->header.image_size = offset; 1507 ret = qed_write_header_sync(s); 1508 if (ret < 0) { 1509 s->header.image_size = old_image_size; 1510 } 1511 return ret; 1512 } 1513 1514 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1515 { 1516 BDRVQEDState *s = bs->opaque; 1517 return s->header.image_size; 1518 } 1519 1520 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1521 { 1522 BDRVQEDState *s = bs->opaque; 1523 1524 memset(bdi, 0, sizeof(*bdi)); 1525 bdi->cluster_size = s->header.cluster_size; 1526 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1527 bdi->unallocated_blocks_are_zero = true; 1528 bdi->can_write_zeroes_with_unmap = true; 1529 return 0; 1530 } 1531 1532 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1533 const char *backing_file, 1534 const char *backing_fmt) 1535 { 1536 BDRVQEDState *s = bs->opaque; 1537 QEDHeader new_header, le_header; 1538 void *buffer; 1539 size_t buffer_len, backing_file_len; 1540 int ret; 1541 1542 /* Refuse to set backing filename if unknown compat feature bits are 1543 * active. If the image uses an unknown compat feature then we may not 1544 * know the layout of data following the header structure and cannot safely 1545 * add a new string. 1546 */ 1547 if (backing_file && (s->header.compat_features & 1548 ~QED_COMPAT_FEATURE_MASK)) { 1549 return -ENOTSUP; 1550 } 1551 1552 memcpy(&new_header, &s->header, sizeof(new_header)); 1553 1554 new_header.features &= ~(QED_F_BACKING_FILE | 1555 QED_F_BACKING_FORMAT_NO_PROBE); 1556 1557 /* Adjust feature flags */ 1558 if (backing_file) { 1559 new_header.features |= QED_F_BACKING_FILE; 1560 1561 if (qed_fmt_is_raw(backing_fmt)) { 1562 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1563 } 1564 } 1565 1566 /* Calculate new header size */ 1567 backing_file_len = 0; 1568 1569 if (backing_file) { 1570 backing_file_len = strlen(backing_file); 1571 } 1572 1573 buffer_len = sizeof(new_header); 1574 new_header.backing_filename_offset = buffer_len; 1575 new_header.backing_filename_size = backing_file_len; 1576 buffer_len += backing_file_len; 1577 1578 /* Make sure we can rewrite header without failing */ 1579 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1580 return -ENOSPC; 1581 } 1582 1583 /* Prepare new header */ 1584 buffer = g_malloc(buffer_len); 1585 1586 qed_header_cpu_to_le(&new_header, &le_header); 1587 memcpy(buffer, &le_header, sizeof(le_header)); 1588 buffer_len = sizeof(le_header); 1589 1590 if (backing_file) { 1591 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1592 buffer_len += backing_file_len; 1593 } 1594 1595 /* Write new header */ 1596 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1597 g_free(buffer); 1598 if (ret == 0) { 1599 memcpy(&s->header, &new_header, sizeof(new_header)); 1600 } 1601 return ret; 1602 } 1603 1604 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1605 { 1606 BDRVQEDState *s = bs->opaque; 1607 Error *local_err = NULL; 1608 int ret; 1609 1610 bdrv_qed_close(bs); 1611 1612 bdrv_invalidate_cache(bs->file, &local_err); 1613 if (local_err) { 1614 error_propagate(errp, local_err); 1615 return; 1616 } 1617 1618 memset(s, 0, sizeof(BDRVQEDState)); 1619 ret = bdrv_qed_open(bs, NULL, bs->open_flags, &local_err); 1620 if (local_err) { 1621 error_setg(errp, "Could not reopen qed layer: %s", 1622 error_get_pretty(local_err)); 1623 error_free(local_err); 1624 return; 1625 } else if (ret < 0) { 1626 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1627 return; 1628 } 1629 } 1630 1631 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1632 BdrvCheckMode fix) 1633 { 1634 BDRVQEDState *s = bs->opaque; 1635 1636 return qed_check(s, result, !!fix); 1637 } 1638 1639 static QemuOptsList qed_create_opts = { 1640 .name = "qed-create-opts", 1641 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1642 .desc = { 1643 { 1644 .name = BLOCK_OPT_SIZE, 1645 .type = QEMU_OPT_SIZE, 1646 .help = "Virtual disk size" 1647 }, 1648 { 1649 .name = BLOCK_OPT_BACKING_FILE, 1650 .type = QEMU_OPT_STRING, 1651 .help = "File name of a base image" 1652 }, 1653 { 1654 .name = BLOCK_OPT_BACKING_FMT, 1655 .type = QEMU_OPT_STRING, 1656 .help = "Image format of the base image" 1657 }, 1658 { 1659 .name = BLOCK_OPT_CLUSTER_SIZE, 1660 .type = QEMU_OPT_SIZE, 1661 .help = "Cluster size (in bytes)", 1662 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1663 }, 1664 { 1665 .name = BLOCK_OPT_TABLE_SIZE, 1666 .type = QEMU_OPT_SIZE, 1667 .help = "L1/L2 table size (in clusters)" 1668 }, 1669 { /* end of list */ } 1670 } 1671 }; 1672 1673 static BlockDriver bdrv_qed = { 1674 .format_name = "qed", 1675 .instance_size = sizeof(BDRVQEDState), 1676 .create_opts = &qed_create_opts, 1677 .supports_backing = true, 1678 1679 .bdrv_probe = bdrv_qed_probe, 1680 .bdrv_rebind = bdrv_qed_rebind, 1681 .bdrv_open = bdrv_qed_open, 1682 .bdrv_close = bdrv_qed_close, 1683 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1684 .bdrv_create = bdrv_qed_create, 1685 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1686 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1687 .bdrv_aio_readv = bdrv_qed_aio_readv, 1688 .bdrv_aio_writev = bdrv_qed_aio_writev, 1689 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes, 1690 .bdrv_truncate = bdrv_qed_truncate, 1691 .bdrv_getlength = bdrv_qed_getlength, 1692 .bdrv_get_info = bdrv_qed_get_info, 1693 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1694 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1695 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1696 .bdrv_check = bdrv_qed_check, 1697 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1698 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1699 }; 1700 1701 static void bdrv_qed_init(void) 1702 { 1703 bdrv_register(&bdrv_qed); 1704 } 1705 1706 block_init(bdrv_qed_init); 1707