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 void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp) 532 { 533 BDRVQEDState *s = bs->opaque; 534 535 bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS; 536 } 537 538 /* We have nothing to do for QED reopen, stubs just return 539 * success */ 540 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 541 BlockReopenQueue *queue, Error **errp) 542 { 543 return 0; 544 } 545 546 static void bdrv_qed_close(BlockDriverState *bs) 547 { 548 BDRVQEDState *s = bs->opaque; 549 550 bdrv_qed_detach_aio_context(bs); 551 552 /* Ensure writes reach stable storage */ 553 bdrv_flush(bs->file); 554 555 /* Clean shutdown, no check required on next open */ 556 if (s->header.features & QED_F_NEED_CHECK) { 557 s->header.features &= ~QED_F_NEED_CHECK; 558 qed_write_header_sync(s); 559 } 560 561 qed_free_l2_cache(&s->l2_cache); 562 qemu_vfree(s->l1_table); 563 } 564 565 static int qed_create(const char *filename, uint32_t cluster_size, 566 uint64_t image_size, uint32_t table_size, 567 const char *backing_file, const char *backing_fmt, 568 QemuOpts *opts, Error **errp) 569 { 570 QEDHeader header = { 571 .magic = QED_MAGIC, 572 .cluster_size = cluster_size, 573 .table_size = table_size, 574 .header_size = 1, 575 .features = 0, 576 .compat_features = 0, 577 .l1_table_offset = cluster_size, 578 .image_size = image_size, 579 }; 580 QEDHeader le_header; 581 uint8_t *l1_table = NULL; 582 size_t l1_size = header.cluster_size * header.table_size; 583 Error *local_err = NULL; 584 int ret = 0; 585 BlockDriverState *bs; 586 587 ret = bdrv_create_file(filename, opts, &local_err); 588 if (ret < 0) { 589 error_propagate(errp, local_err); 590 return ret; 591 } 592 593 bs = NULL; 594 ret = bdrv_open(&bs, filename, NULL, NULL, 595 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, NULL, 596 &local_err); 597 if (ret < 0) { 598 error_propagate(errp, local_err); 599 return ret; 600 } 601 602 /* File must start empty and grow, check truncate is supported */ 603 ret = bdrv_truncate(bs, 0); 604 if (ret < 0) { 605 goto out; 606 } 607 608 if (backing_file) { 609 header.features |= QED_F_BACKING_FILE; 610 header.backing_filename_offset = sizeof(le_header); 611 header.backing_filename_size = strlen(backing_file); 612 613 if (qed_fmt_is_raw(backing_fmt)) { 614 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 615 } 616 } 617 618 qed_header_cpu_to_le(&header, &le_header); 619 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); 620 if (ret < 0) { 621 goto out; 622 } 623 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file, 624 header.backing_filename_size); 625 if (ret < 0) { 626 goto out; 627 } 628 629 l1_table = g_malloc0(l1_size); 630 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size); 631 if (ret < 0) { 632 goto out; 633 } 634 635 ret = 0; /* success */ 636 out: 637 g_free(l1_table); 638 bdrv_unref(bs); 639 return ret; 640 } 641 642 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 643 { 644 uint64_t image_size = 0; 645 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 646 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 647 char *backing_file = NULL; 648 char *backing_fmt = NULL; 649 int ret; 650 651 image_size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 652 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 653 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 654 cluster_size = qemu_opt_get_size_del(opts, 655 BLOCK_OPT_CLUSTER_SIZE, 656 QED_DEFAULT_CLUSTER_SIZE); 657 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 658 QED_DEFAULT_TABLE_SIZE); 659 660 if (!qed_is_cluster_size_valid(cluster_size)) { 661 error_setg(errp, "QED cluster size must be within range [%u, %u] " 662 "and power of 2", 663 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 664 ret = -EINVAL; 665 goto finish; 666 } 667 if (!qed_is_table_size_valid(table_size)) { 668 error_setg(errp, "QED table size must be within range [%u, %u] " 669 "and power of 2", 670 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 671 ret = -EINVAL; 672 goto finish; 673 } 674 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 675 error_setg(errp, "QED image size must be a non-zero multiple of " 676 "cluster size and less than %" PRIu64 " bytes", 677 qed_max_image_size(cluster_size, table_size)); 678 ret = -EINVAL; 679 goto finish; 680 } 681 682 ret = qed_create(filename, cluster_size, image_size, table_size, 683 backing_file, backing_fmt, opts, errp); 684 685 finish: 686 g_free(backing_file); 687 g_free(backing_fmt); 688 return ret; 689 } 690 691 typedef struct { 692 BlockDriverState *bs; 693 Coroutine *co; 694 uint64_t pos; 695 int64_t status; 696 int *pnum; 697 } QEDIsAllocatedCB; 698 699 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 700 { 701 QEDIsAllocatedCB *cb = opaque; 702 BDRVQEDState *s = cb->bs->opaque; 703 *cb->pnum = len / BDRV_SECTOR_SIZE; 704 switch (ret) { 705 case QED_CLUSTER_FOUND: 706 offset |= qed_offset_into_cluster(s, cb->pos); 707 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 708 break; 709 case QED_CLUSTER_ZERO: 710 cb->status = BDRV_BLOCK_ZERO; 711 break; 712 case QED_CLUSTER_L2: 713 case QED_CLUSTER_L1: 714 cb->status = 0; 715 break; 716 default: 717 assert(ret < 0); 718 cb->status = ret; 719 break; 720 } 721 722 if (cb->co) { 723 qemu_coroutine_enter(cb->co, NULL); 724 } 725 } 726 727 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 728 int64_t sector_num, 729 int nb_sectors, int *pnum) 730 { 731 BDRVQEDState *s = bs->opaque; 732 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 733 QEDIsAllocatedCB cb = { 734 .bs = bs, 735 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 736 .status = BDRV_BLOCK_OFFSET_MASK, 737 .pnum = pnum, 738 }; 739 QEDRequest request = { .l2_table = NULL }; 740 741 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 742 743 /* Now sleep if the callback wasn't invoked immediately */ 744 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 745 cb.co = qemu_coroutine_self(); 746 qemu_coroutine_yield(); 747 } 748 749 qed_unref_l2_cache_entry(request.l2_table); 750 751 return cb.status; 752 } 753 754 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 755 { 756 return acb->common.bs->opaque; 757 } 758 759 /** 760 * Read from the backing file or zero-fill if no backing file 761 * 762 * @s: QED state 763 * @pos: Byte position in device 764 * @qiov: Destination I/O vector 765 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 766 * @cb: Completion function 767 * @opaque: User data for completion function 768 * 769 * This function reads qiov->size bytes starting at pos from the backing file. 770 * If there is no backing file then zeroes are read. 771 */ 772 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 773 QEMUIOVector *qiov, 774 QEMUIOVector **backing_qiov, 775 BlockDriverCompletionFunc *cb, void *opaque) 776 { 777 uint64_t backing_length = 0; 778 size_t size; 779 780 /* If there is a backing file, get its length. Treat the absence of a 781 * backing file like a zero length backing file. 782 */ 783 if (s->bs->backing_hd) { 784 int64_t l = bdrv_getlength(s->bs->backing_hd); 785 if (l < 0) { 786 cb(opaque, l); 787 return; 788 } 789 backing_length = l; 790 } 791 792 /* Zero all sectors if reading beyond the end of the backing file */ 793 if (pos >= backing_length || 794 pos + qiov->size > backing_length) { 795 qemu_iovec_memset(qiov, 0, 0, qiov->size); 796 } 797 798 /* Complete now if there are no backing file sectors to read */ 799 if (pos >= backing_length) { 800 cb(opaque, 0); 801 return; 802 } 803 804 /* If the read straddles the end of the backing file, shorten it */ 805 size = MIN((uint64_t)backing_length - pos, qiov->size); 806 807 assert(*backing_qiov == NULL); 808 *backing_qiov = g_new(QEMUIOVector, 1); 809 qemu_iovec_init(*backing_qiov, qiov->niov); 810 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 811 812 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 813 bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE, 814 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 815 } 816 817 typedef struct { 818 GenericCB gencb; 819 BDRVQEDState *s; 820 QEMUIOVector qiov; 821 QEMUIOVector *backing_qiov; 822 struct iovec iov; 823 uint64_t offset; 824 } CopyFromBackingFileCB; 825 826 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 827 { 828 CopyFromBackingFileCB *copy_cb = opaque; 829 qemu_vfree(copy_cb->iov.iov_base); 830 gencb_complete(©_cb->gencb, ret); 831 } 832 833 static void qed_copy_from_backing_file_write(void *opaque, int ret) 834 { 835 CopyFromBackingFileCB *copy_cb = opaque; 836 BDRVQEDState *s = copy_cb->s; 837 838 if (copy_cb->backing_qiov) { 839 qemu_iovec_destroy(copy_cb->backing_qiov); 840 g_free(copy_cb->backing_qiov); 841 copy_cb->backing_qiov = NULL; 842 } 843 844 if (ret) { 845 qed_copy_from_backing_file_cb(copy_cb, ret); 846 return; 847 } 848 849 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 850 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 851 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 852 qed_copy_from_backing_file_cb, copy_cb); 853 } 854 855 /** 856 * Copy data from backing file into the image 857 * 858 * @s: QED state 859 * @pos: Byte position in device 860 * @len: Number of bytes 861 * @offset: Byte offset in image file 862 * @cb: Completion function 863 * @opaque: User data for completion function 864 */ 865 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 866 uint64_t len, uint64_t offset, 867 BlockDriverCompletionFunc *cb, 868 void *opaque) 869 { 870 CopyFromBackingFileCB *copy_cb; 871 872 /* Skip copy entirely if there is no work to do */ 873 if (len == 0) { 874 cb(opaque, 0); 875 return; 876 } 877 878 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 879 copy_cb->s = s; 880 copy_cb->offset = offset; 881 copy_cb->backing_qiov = NULL; 882 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 883 copy_cb->iov.iov_len = len; 884 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 885 886 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 887 qed_copy_from_backing_file_write, copy_cb); 888 } 889 890 /** 891 * Link one or more contiguous clusters into a table 892 * 893 * @s: QED state 894 * @table: L2 table 895 * @index: First cluster index 896 * @n: Number of contiguous clusters 897 * @cluster: First cluster offset 898 * 899 * The cluster offset may be an allocated byte offset in the image file, the 900 * zero cluster marker, or the unallocated cluster marker. 901 */ 902 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 903 unsigned int n, uint64_t cluster) 904 { 905 int i; 906 for (i = index; i < index + n; i++) { 907 table->offsets[i] = cluster; 908 if (!qed_offset_is_unalloc_cluster(cluster) && 909 !qed_offset_is_zero_cluster(cluster)) { 910 cluster += s->header.cluster_size; 911 } 912 } 913 } 914 915 static void qed_aio_complete_bh(void *opaque) 916 { 917 QEDAIOCB *acb = opaque; 918 BlockDriverCompletionFunc *cb = acb->common.cb; 919 void *user_opaque = acb->common.opaque; 920 int ret = acb->bh_ret; 921 bool *finished = acb->finished; 922 923 qemu_bh_delete(acb->bh); 924 qemu_aio_release(acb); 925 926 /* Invoke callback */ 927 cb(user_opaque, ret); 928 929 /* Signal cancel completion */ 930 if (finished) { 931 *finished = true; 932 } 933 } 934 935 static void qed_aio_complete(QEDAIOCB *acb, int ret) 936 { 937 BDRVQEDState *s = acb_to_s(acb); 938 939 trace_qed_aio_complete(s, acb, ret); 940 941 /* Free resources */ 942 qemu_iovec_destroy(&acb->cur_qiov); 943 qed_unref_l2_cache_entry(acb->request.l2_table); 944 945 /* Free the buffer we may have allocated for zero writes */ 946 if (acb->flags & QED_AIOCB_ZERO) { 947 qemu_vfree(acb->qiov->iov[0].iov_base); 948 acb->qiov->iov[0].iov_base = NULL; 949 } 950 951 /* Arrange for a bh to invoke the completion function */ 952 acb->bh_ret = ret; 953 acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs), 954 qed_aio_complete_bh, acb); 955 qemu_bh_schedule(acb->bh); 956 957 /* Start next allocating write request waiting behind this one. Note that 958 * requests enqueue themselves when they first hit an unallocated cluster 959 * but they wait until the entire request is finished before waking up the 960 * next request in the queue. This ensures that we don't cycle through 961 * requests multiple times but rather finish one at a time completely. 962 */ 963 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 964 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 965 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 966 if (acb) { 967 qed_aio_next_io(acb, 0); 968 } else if (s->header.features & QED_F_NEED_CHECK) { 969 qed_start_need_check_timer(s); 970 } 971 } 972 } 973 974 /** 975 * Commit the current L2 table to the cache 976 */ 977 static void qed_commit_l2_update(void *opaque, int ret) 978 { 979 QEDAIOCB *acb = opaque; 980 BDRVQEDState *s = acb_to_s(acb); 981 CachedL2Table *l2_table = acb->request.l2_table; 982 uint64_t l2_offset = l2_table->offset; 983 984 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 985 986 /* This is guaranteed to succeed because we just committed the entry to the 987 * cache. 988 */ 989 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 990 assert(acb->request.l2_table != NULL); 991 992 qed_aio_next_io(opaque, ret); 993 } 994 995 /** 996 * Update L1 table with new L2 table offset and write it out 997 */ 998 static void qed_aio_write_l1_update(void *opaque, int ret) 999 { 1000 QEDAIOCB *acb = opaque; 1001 BDRVQEDState *s = acb_to_s(acb); 1002 int index; 1003 1004 if (ret) { 1005 qed_aio_complete(acb, ret); 1006 return; 1007 } 1008 1009 index = qed_l1_index(s, acb->cur_pos); 1010 s->l1_table->offsets[index] = acb->request.l2_table->offset; 1011 1012 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 1013 } 1014 1015 /** 1016 * Update L2 table with new cluster offsets and write them out 1017 */ 1018 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 1019 { 1020 BDRVQEDState *s = acb_to_s(acb); 1021 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1022 int index; 1023 1024 if (ret) { 1025 goto err; 1026 } 1027 1028 if (need_alloc) { 1029 qed_unref_l2_cache_entry(acb->request.l2_table); 1030 acb->request.l2_table = qed_new_l2_table(s); 1031 } 1032 1033 index = qed_l2_index(s, acb->cur_pos); 1034 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1035 offset); 1036 1037 if (need_alloc) { 1038 /* Write out the whole new L2 table */ 1039 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1040 qed_aio_write_l1_update, acb); 1041 } else { 1042 /* Write out only the updated part of the L2 table */ 1043 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1044 qed_aio_next_io, acb); 1045 } 1046 return; 1047 1048 err: 1049 qed_aio_complete(acb, ret); 1050 } 1051 1052 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1053 { 1054 QEDAIOCB *acb = opaque; 1055 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1056 } 1057 1058 /** 1059 * Flush new data clusters before updating the L2 table 1060 * 1061 * This flush is necessary when a backing file is in use. A crash during an 1062 * allocating write could result in empty clusters in the image. If the write 1063 * only touched a subregion of the cluster, then backing image sectors have 1064 * been lost in the untouched region. The solution is to flush after writing a 1065 * new data cluster and before updating the L2 table. 1066 */ 1067 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1068 { 1069 QEDAIOCB *acb = opaque; 1070 BDRVQEDState *s = acb_to_s(acb); 1071 1072 if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update_cb, opaque)) { 1073 qed_aio_complete(acb, -EIO); 1074 } 1075 } 1076 1077 /** 1078 * Write data to the image file 1079 */ 1080 static void qed_aio_write_main(void *opaque, int ret) 1081 { 1082 QEDAIOCB *acb = opaque; 1083 BDRVQEDState *s = acb_to_s(acb); 1084 uint64_t offset = acb->cur_cluster + 1085 qed_offset_into_cluster(s, acb->cur_pos); 1086 BlockDriverCompletionFunc *next_fn; 1087 1088 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1089 1090 if (ret) { 1091 qed_aio_complete(acb, ret); 1092 return; 1093 } 1094 1095 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1096 next_fn = qed_aio_next_io; 1097 } else { 1098 if (s->bs->backing_hd) { 1099 next_fn = qed_aio_write_flush_before_l2_update; 1100 } else { 1101 next_fn = qed_aio_write_l2_update_cb; 1102 } 1103 } 1104 1105 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1106 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1107 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1108 next_fn, acb); 1109 } 1110 1111 /** 1112 * Populate back untouched region of new data cluster 1113 */ 1114 static void qed_aio_write_postfill(void *opaque, int ret) 1115 { 1116 QEDAIOCB *acb = opaque; 1117 BDRVQEDState *s = acb_to_s(acb); 1118 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1119 uint64_t len = 1120 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1121 uint64_t offset = acb->cur_cluster + 1122 qed_offset_into_cluster(s, acb->cur_pos) + 1123 acb->cur_qiov.size; 1124 1125 if (ret) { 1126 qed_aio_complete(acb, ret); 1127 return; 1128 } 1129 1130 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1131 qed_copy_from_backing_file(s, start, len, offset, 1132 qed_aio_write_main, acb); 1133 } 1134 1135 /** 1136 * Populate front untouched region of new data cluster 1137 */ 1138 static void qed_aio_write_prefill(void *opaque, int ret) 1139 { 1140 QEDAIOCB *acb = opaque; 1141 BDRVQEDState *s = acb_to_s(acb); 1142 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1143 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1144 1145 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1146 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1147 qed_aio_write_postfill, acb); 1148 } 1149 1150 /** 1151 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1152 */ 1153 static bool qed_should_set_need_check(BDRVQEDState *s) 1154 { 1155 /* The flush before L2 update path ensures consistency */ 1156 if (s->bs->backing_hd) { 1157 return false; 1158 } 1159 1160 return !(s->header.features & QED_F_NEED_CHECK); 1161 } 1162 1163 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1164 { 1165 QEDAIOCB *acb = opaque; 1166 1167 if (ret) { 1168 qed_aio_complete(acb, ret); 1169 return; 1170 } 1171 1172 qed_aio_write_l2_update(acb, 0, 1); 1173 } 1174 1175 /** 1176 * Write new data cluster 1177 * 1178 * @acb: Write request 1179 * @len: Length in bytes 1180 * 1181 * This path is taken when writing to previously unallocated clusters. 1182 */ 1183 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1184 { 1185 BDRVQEDState *s = acb_to_s(acb); 1186 BlockDriverCompletionFunc *cb; 1187 1188 /* Cancel timer when the first allocating request comes in */ 1189 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1190 qed_cancel_need_check_timer(s); 1191 } 1192 1193 /* Freeze this request if another allocating write is in progress */ 1194 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1195 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1196 } 1197 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1198 s->allocating_write_reqs_plugged) { 1199 return; /* wait for existing request to finish */ 1200 } 1201 1202 acb->cur_nclusters = qed_bytes_to_clusters(s, 1203 qed_offset_into_cluster(s, acb->cur_pos) + len); 1204 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1205 1206 if (acb->flags & QED_AIOCB_ZERO) { 1207 /* Skip ahead if the clusters are already zero */ 1208 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1209 qed_aio_next_io(acb, 0); 1210 return; 1211 } 1212 1213 cb = qed_aio_write_zero_cluster; 1214 } else { 1215 cb = qed_aio_write_prefill; 1216 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1217 } 1218 1219 if (qed_should_set_need_check(s)) { 1220 s->header.features |= QED_F_NEED_CHECK; 1221 qed_write_header(s, cb, acb); 1222 } else { 1223 cb(acb, 0); 1224 } 1225 } 1226 1227 /** 1228 * Write data cluster in place 1229 * 1230 * @acb: Write request 1231 * @offset: Cluster offset in bytes 1232 * @len: Length in bytes 1233 * 1234 * This path is taken when writing to already allocated clusters. 1235 */ 1236 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1237 { 1238 /* Allocate buffer for zero writes */ 1239 if (acb->flags & QED_AIOCB_ZERO) { 1240 struct iovec *iov = acb->qiov->iov; 1241 1242 if (!iov->iov_base) { 1243 iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len); 1244 if (iov->iov_base == NULL) { 1245 qed_aio_complete(acb, -ENOMEM); 1246 return; 1247 } 1248 memset(iov->iov_base, 0, iov->iov_len); 1249 } 1250 } 1251 1252 /* Calculate the I/O vector */ 1253 acb->cur_cluster = offset; 1254 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1255 1256 /* Do the actual write */ 1257 qed_aio_write_main(acb, 0); 1258 } 1259 1260 /** 1261 * Write data cluster 1262 * 1263 * @opaque: Write request 1264 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1265 * or -errno 1266 * @offset: Cluster offset in bytes 1267 * @len: Length in bytes 1268 * 1269 * Callback from qed_find_cluster(). 1270 */ 1271 static void qed_aio_write_data(void *opaque, int ret, 1272 uint64_t offset, size_t len) 1273 { 1274 QEDAIOCB *acb = opaque; 1275 1276 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1277 1278 acb->find_cluster_ret = ret; 1279 1280 switch (ret) { 1281 case QED_CLUSTER_FOUND: 1282 qed_aio_write_inplace(acb, offset, len); 1283 break; 1284 1285 case QED_CLUSTER_L2: 1286 case QED_CLUSTER_L1: 1287 case QED_CLUSTER_ZERO: 1288 qed_aio_write_alloc(acb, len); 1289 break; 1290 1291 default: 1292 qed_aio_complete(acb, ret); 1293 break; 1294 } 1295 } 1296 1297 /** 1298 * Read data cluster 1299 * 1300 * @opaque: Read request 1301 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1302 * or -errno 1303 * @offset: Cluster offset in bytes 1304 * @len: Length in bytes 1305 * 1306 * Callback from qed_find_cluster(). 1307 */ 1308 static void qed_aio_read_data(void *opaque, int ret, 1309 uint64_t offset, size_t len) 1310 { 1311 QEDAIOCB *acb = opaque; 1312 BDRVQEDState *s = acb_to_s(acb); 1313 BlockDriverState *bs = acb->common.bs; 1314 1315 /* Adjust offset into cluster */ 1316 offset += qed_offset_into_cluster(s, acb->cur_pos); 1317 1318 trace_qed_aio_read_data(s, acb, ret, offset, len); 1319 1320 if (ret < 0) { 1321 goto err; 1322 } 1323 1324 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1325 1326 /* Handle zero cluster and backing file reads */ 1327 if (ret == QED_CLUSTER_ZERO) { 1328 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1329 qed_aio_next_io(acb, 0); 1330 return; 1331 } else if (ret != QED_CLUSTER_FOUND) { 1332 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1333 &acb->backing_qiov, qed_aio_next_io, acb); 1334 return; 1335 } 1336 1337 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1338 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1339 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1340 qed_aio_next_io, acb); 1341 return; 1342 1343 err: 1344 qed_aio_complete(acb, ret); 1345 } 1346 1347 /** 1348 * Begin next I/O or complete the request 1349 */ 1350 static void qed_aio_next_io(void *opaque, int ret) 1351 { 1352 QEDAIOCB *acb = opaque; 1353 BDRVQEDState *s = acb_to_s(acb); 1354 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1355 qed_aio_write_data : qed_aio_read_data; 1356 1357 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1358 1359 if (acb->backing_qiov) { 1360 qemu_iovec_destroy(acb->backing_qiov); 1361 g_free(acb->backing_qiov); 1362 acb->backing_qiov = NULL; 1363 } 1364 1365 /* Handle I/O error */ 1366 if (ret) { 1367 qed_aio_complete(acb, ret); 1368 return; 1369 } 1370 1371 acb->qiov_offset += acb->cur_qiov.size; 1372 acb->cur_pos += acb->cur_qiov.size; 1373 qemu_iovec_reset(&acb->cur_qiov); 1374 1375 /* Complete request */ 1376 if (acb->cur_pos >= acb->end_pos) { 1377 qed_aio_complete(acb, 0); 1378 return; 1379 } 1380 1381 /* Find next cluster and start I/O */ 1382 qed_find_cluster(s, &acb->request, 1383 acb->cur_pos, acb->end_pos - acb->cur_pos, 1384 io_fn, acb); 1385 } 1386 1387 static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs, 1388 int64_t sector_num, 1389 QEMUIOVector *qiov, int nb_sectors, 1390 BlockDriverCompletionFunc *cb, 1391 void *opaque, int flags) 1392 { 1393 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1394 1395 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1396 opaque, flags); 1397 1398 acb->flags = flags; 1399 acb->finished = NULL; 1400 acb->qiov = qiov; 1401 acb->qiov_offset = 0; 1402 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1403 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1404 acb->backing_qiov = NULL; 1405 acb->request.l2_table = NULL; 1406 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1407 1408 /* Start request */ 1409 qed_aio_next_io(acb, 0); 1410 return &acb->common; 1411 } 1412 1413 static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1414 int64_t sector_num, 1415 QEMUIOVector *qiov, int nb_sectors, 1416 BlockDriverCompletionFunc *cb, 1417 void *opaque) 1418 { 1419 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1420 } 1421 1422 static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1423 int64_t sector_num, 1424 QEMUIOVector *qiov, int nb_sectors, 1425 BlockDriverCompletionFunc *cb, 1426 void *opaque) 1427 { 1428 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1429 opaque, QED_AIOCB_WRITE); 1430 } 1431 1432 typedef struct { 1433 Coroutine *co; 1434 int ret; 1435 bool done; 1436 } QEDWriteZeroesCB; 1437 1438 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret) 1439 { 1440 QEDWriteZeroesCB *cb = opaque; 1441 1442 cb->done = true; 1443 cb->ret = ret; 1444 if (cb->co) { 1445 qemu_coroutine_enter(cb->co, NULL); 1446 } 1447 } 1448 1449 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs, 1450 int64_t sector_num, 1451 int nb_sectors, 1452 BdrvRequestFlags flags) 1453 { 1454 BlockDriverAIOCB *blockacb; 1455 BDRVQEDState *s = bs->opaque; 1456 QEDWriteZeroesCB cb = { .done = false }; 1457 QEMUIOVector qiov; 1458 struct iovec iov; 1459 1460 /* Refuse if there are untouched backing file sectors */ 1461 if (bs->backing_hd) { 1462 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) { 1463 return -ENOTSUP; 1464 } 1465 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) { 1466 return -ENOTSUP; 1467 } 1468 } 1469 1470 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1471 * then it will be allocated during request processing. 1472 */ 1473 iov.iov_base = NULL, 1474 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE, 1475 1476 qemu_iovec_init_external(&qiov, &iov, 1); 1477 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors, 1478 qed_co_write_zeroes_cb, &cb, 1479 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1480 if (!blockacb) { 1481 return -EIO; 1482 } 1483 if (!cb.done) { 1484 cb.co = qemu_coroutine_self(); 1485 qemu_coroutine_yield(); 1486 } 1487 assert(cb.done); 1488 return cb.ret; 1489 } 1490 1491 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1492 { 1493 BDRVQEDState *s = bs->opaque; 1494 uint64_t old_image_size; 1495 int ret; 1496 1497 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1498 s->header.table_size)) { 1499 return -EINVAL; 1500 } 1501 1502 /* Shrinking is currently not supported */ 1503 if ((uint64_t)offset < s->header.image_size) { 1504 return -ENOTSUP; 1505 } 1506 1507 old_image_size = s->header.image_size; 1508 s->header.image_size = offset; 1509 ret = qed_write_header_sync(s); 1510 if (ret < 0) { 1511 s->header.image_size = old_image_size; 1512 } 1513 return ret; 1514 } 1515 1516 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1517 { 1518 BDRVQEDState *s = bs->opaque; 1519 return s->header.image_size; 1520 } 1521 1522 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1523 { 1524 BDRVQEDState *s = bs->opaque; 1525 1526 memset(bdi, 0, sizeof(*bdi)); 1527 bdi->cluster_size = s->header.cluster_size; 1528 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1529 bdi->unallocated_blocks_are_zero = true; 1530 bdi->can_write_zeroes_with_unmap = true; 1531 return 0; 1532 } 1533 1534 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1535 const char *backing_file, 1536 const char *backing_fmt) 1537 { 1538 BDRVQEDState *s = bs->opaque; 1539 QEDHeader new_header, le_header; 1540 void *buffer; 1541 size_t buffer_len, backing_file_len; 1542 int ret; 1543 1544 /* Refuse to set backing filename if unknown compat feature bits are 1545 * active. If the image uses an unknown compat feature then we may not 1546 * know the layout of data following the header structure and cannot safely 1547 * add a new string. 1548 */ 1549 if (backing_file && (s->header.compat_features & 1550 ~QED_COMPAT_FEATURE_MASK)) { 1551 return -ENOTSUP; 1552 } 1553 1554 memcpy(&new_header, &s->header, sizeof(new_header)); 1555 1556 new_header.features &= ~(QED_F_BACKING_FILE | 1557 QED_F_BACKING_FORMAT_NO_PROBE); 1558 1559 /* Adjust feature flags */ 1560 if (backing_file) { 1561 new_header.features |= QED_F_BACKING_FILE; 1562 1563 if (qed_fmt_is_raw(backing_fmt)) { 1564 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1565 } 1566 } 1567 1568 /* Calculate new header size */ 1569 backing_file_len = 0; 1570 1571 if (backing_file) { 1572 backing_file_len = strlen(backing_file); 1573 } 1574 1575 buffer_len = sizeof(new_header); 1576 new_header.backing_filename_offset = buffer_len; 1577 new_header.backing_filename_size = backing_file_len; 1578 buffer_len += backing_file_len; 1579 1580 /* Make sure we can rewrite header without failing */ 1581 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1582 return -ENOSPC; 1583 } 1584 1585 /* Prepare new header */ 1586 buffer = g_malloc(buffer_len); 1587 1588 qed_header_cpu_to_le(&new_header, &le_header); 1589 memcpy(buffer, &le_header, sizeof(le_header)); 1590 buffer_len = sizeof(le_header); 1591 1592 if (backing_file) { 1593 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1594 buffer_len += backing_file_len; 1595 } 1596 1597 /* Write new header */ 1598 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1599 g_free(buffer); 1600 if (ret == 0) { 1601 memcpy(&s->header, &new_header, sizeof(new_header)); 1602 } 1603 return ret; 1604 } 1605 1606 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1607 { 1608 BDRVQEDState *s = bs->opaque; 1609 Error *local_err = NULL; 1610 int ret; 1611 1612 bdrv_qed_close(bs); 1613 1614 bdrv_invalidate_cache(bs->file, &local_err); 1615 if (local_err) { 1616 error_propagate(errp, local_err); 1617 return; 1618 } 1619 1620 memset(s, 0, sizeof(BDRVQEDState)); 1621 ret = bdrv_qed_open(bs, NULL, bs->open_flags, &local_err); 1622 if (local_err) { 1623 error_setg(errp, "Could not reopen qed layer: %s", 1624 error_get_pretty(local_err)); 1625 error_free(local_err); 1626 return; 1627 } else if (ret < 0) { 1628 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1629 return; 1630 } 1631 } 1632 1633 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1634 BdrvCheckMode fix) 1635 { 1636 BDRVQEDState *s = bs->opaque; 1637 1638 return qed_check(s, result, !!fix); 1639 } 1640 1641 static QemuOptsList qed_create_opts = { 1642 .name = "qed-create-opts", 1643 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1644 .desc = { 1645 { 1646 .name = BLOCK_OPT_SIZE, 1647 .type = QEMU_OPT_SIZE, 1648 .help = "Virtual disk size" 1649 }, 1650 { 1651 .name = BLOCK_OPT_BACKING_FILE, 1652 .type = QEMU_OPT_STRING, 1653 .help = "File name of a base image" 1654 }, 1655 { 1656 .name = BLOCK_OPT_BACKING_FMT, 1657 .type = QEMU_OPT_STRING, 1658 .help = "Image format of the base image" 1659 }, 1660 { 1661 .name = BLOCK_OPT_CLUSTER_SIZE, 1662 .type = QEMU_OPT_SIZE, 1663 .help = "Cluster size (in bytes)", 1664 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1665 }, 1666 { 1667 .name = BLOCK_OPT_TABLE_SIZE, 1668 .type = QEMU_OPT_SIZE, 1669 .help = "L1/L2 table size (in clusters)" 1670 }, 1671 { /* end of list */ } 1672 } 1673 }; 1674 1675 static BlockDriver bdrv_qed = { 1676 .format_name = "qed", 1677 .instance_size = sizeof(BDRVQEDState), 1678 .create_opts = &qed_create_opts, 1679 .supports_backing = true, 1680 1681 .bdrv_probe = bdrv_qed_probe, 1682 .bdrv_rebind = bdrv_qed_rebind, 1683 .bdrv_open = bdrv_qed_open, 1684 .bdrv_close = bdrv_qed_close, 1685 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1686 .bdrv_create = bdrv_qed_create, 1687 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1688 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1689 .bdrv_aio_readv = bdrv_qed_aio_readv, 1690 .bdrv_aio_writev = bdrv_qed_aio_writev, 1691 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes, 1692 .bdrv_truncate = bdrv_qed_truncate, 1693 .bdrv_getlength = bdrv_qed_getlength, 1694 .bdrv_get_info = bdrv_qed_get_info, 1695 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1696 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1697 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1698 .bdrv_check = bdrv_qed_check, 1699 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1700 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1701 }; 1702 1703 static void bdrv_qed_init(void) 1704 { 1705 bdrv_register(&bdrv_qed); 1706 } 1707 1708 block_init(bdrv_qed_init); 1709