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 const AIOCBInfo qed_aiocb_info = { 22 .aiocb_size = sizeof(QEDAIOCB), 23 }; 24 25 static int bdrv_qed_probe(const uint8_t *buf, int buf_size, 26 const char *filename) 27 { 28 const QEDHeader *header = (const QEDHeader *)buf; 29 30 if (buf_size < sizeof(*header)) { 31 return 0; 32 } 33 if (le32_to_cpu(header->magic) != QED_MAGIC) { 34 return 0; 35 } 36 return 100; 37 } 38 39 /** 40 * Check whether an image format is raw 41 * 42 * @fmt: Backing file format, may be NULL 43 */ 44 static bool qed_fmt_is_raw(const char *fmt) 45 { 46 return fmt && strcmp(fmt, "raw") == 0; 47 } 48 49 static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu) 50 { 51 cpu->magic = le32_to_cpu(le->magic); 52 cpu->cluster_size = le32_to_cpu(le->cluster_size); 53 cpu->table_size = le32_to_cpu(le->table_size); 54 cpu->header_size = le32_to_cpu(le->header_size); 55 cpu->features = le64_to_cpu(le->features); 56 cpu->compat_features = le64_to_cpu(le->compat_features); 57 cpu->autoclear_features = le64_to_cpu(le->autoclear_features); 58 cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset); 59 cpu->image_size = le64_to_cpu(le->image_size); 60 cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset); 61 cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size); 62 } 63 64 static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le) 65 { 66 le->magic = cpu_to_le32(cpu->magic); 67 le->cluster_size = cpu_to_le32(cpu->cluster_size); 68 le->table_size = cpu_to_le32(cpu->table_size); 69 le->header_size = cpu_to_le32(cpu->header_size); 70 le->features = cpu_to_le64(cpu->features); 71 le->compat_features = cpu_to_le64(cpu->compat_features); 72 le->autoclear_features = cpu_to_le64(cpu->autoclear_features); 73 le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset); 74 le->image_size = cpu_to_le64(cpu->image_size); 75 le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset); 76 le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size); 77 } 78 79 int qed_write_header_sync(BDRVQEDState *s) 80 { 81 QEDHeader le; 82 int ret; 83 84 qed_header_cpu_to_le(&s->header, &le); 85 ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le)); 86 if (ret != sizeof(le)) { 87 return ret; 88 } 89 return 0; 90 } 91 92 typedef struct { 93 GenericCB gencb; 94 BDRVQEDState *s; 95 struct iovec iov; 96 QEMUIOVector qiov; 97 int nsectors; 98 uint8_t *buf; 99 } QEDWriteHeaderCB; 100 101 static void qed_write_header_cb(void *opaque, int ret) 102 { 103 QEDWriteHeaderCB *write_header_cb = opaque; 104 105 qemu_vfree(write_header_cb->buf); 106 gencb_complete(write_header_cb, ret); 107 } 108 109 static void qed_write_header_read_cb(void *opaque, int ret) 110 { 111 QEDWriteHeaderCB *write_header_cb = opaque; 112 BDRVQEDState *s = write_header_cb->s; 113 114 if (ret) { 115 qed_write_header_cb(write_header_cb, ret); 116 return; 117 } 118 119 /* Update header */ 120 qed_header_cpu_to_le(&s->header, (QEDHeader *)write_header_cb->buf); 121 122 bdrv_aio_writev(s->bs->file, 0, &write_header_cb->qiov, 123 write_header_cb->nsectors, qed_write_header_cb, 124 write_header_cb); 125 } 126 127 /** 128 * Update header in-place (does not rewrite backing filename or other strings) 129 * 130 * This function only updates known header fields in-place and does not affect 131 * extra data after the QED header. 132 */ 133 static void qed_write_header(BDRVQEDState *s, BlockDriverCompletionFunc cb, 134 void *opaque) 135 { 136 /* We must write full sectors for O_DIRECT but cannot necessarily generate 137 * the data following the header if an unrecognized compat feature is 138 * active. Therefore, first read the sectors containing the header, update 139 * them, and write back. 140 */ 141 142 int nsectors = (sizeof(QEDHeader) + BDRV_SECTOR_SIZE - 1) / 143 BDRV_SECTOR_SIZE; 144 size_t len = nsectors * BDRV_SECTOR_SIZE; 145 QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb), 146 cb, opaque); 147 148 write_header_cb->s = s; 149 write_header_cb->nsectors = nsectors; 150 write_header_cb->buf = qemu_blockalign(s->bs, len); 151 write_header_cb->iov.iov_base = write_header_cb->buf; 152 write_header_cb->iov.iov_len = len; 153 qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1); 154 155 bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors, 156 qed_write_header_read_cb, write_header_cb); 157 } 158 159 static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size) 160 { 161 uint64_t table_entries; 162 uint64_t l2_size; 163 164 table_entries = (table_size * cluster_size) / sizeof(uint64_t); 165 l2_size = table_entries * cluster_size; 166 167 return l2_size * table_entries; 168 } 169 170 static bool qed_is_cluster_size_valid(uint32_t cluster_size) 171 { 172 if (cluster_size < QED_MIN_CLUSTER_SIZE || 173 cluster_size > QED_MAX_CLUSTER_SIZE) { 174 return false; 175 } 176 if (cluster_size & (cluster_size - 1)) { 177 return false; /* not power of 2 */ 178 } 179 return true; 180 } 181 182 static bool qed_is_table_size_valid(uint32_t table_size) 183 { 184 if (table_size < QED_MIN_TABLE_SIZE || 185 table_size > QED_MAX_TABLE_SIZE) { 186 return false; 187 } 188 if (table_size & (table_size - 1)) { 189 return false; /* not power of 2 */ 190 } 191 return true; 192 } 193 194 static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size, 195 uint32_t table_size) 196 { 197 if (image_size % BDRV_SECTOR_SIZE != 0) { 198 return false; /* not multiple of sector size */ 199 } 200 if (image_size > qed_max_image_size(cluster_size, table_size)) { 201 return false; /* image is too large */ 202 } 203 return true; 204 } 205 206 /** 207 * Read a string of known length from the image file 208 * 209 * @file: Image file 210 * @offset: File offset to start of string, in bytes 211 * @n: String length in bytes 212 * @buf: Destination buffer 213 * @buflen: Destination buffer length in bytes 214 * @ret: 0 on success, -errno on failure 215 * 216 * The string is NUL-terminated. 217 */ 218 static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n, 219 char *buf, size_t buflen) 220 { 221 int ret; 222 if (n >= buflen) { 223 return -EINVAL; 224 } 225 ret = bdrv_pread(file, offset, buf, n); 226 if (ret < 0) { 227 return ret; 228 } 229 buf[n] = '\0'; 230 return 0; 231 } 232 233 /** 234 * Allocate new clusters 235 * 236 * @s: QED state 237 * @n: Number of contiguous clusters to allocate 238 * @ret: Offset of first allocated cluster 239 * 240 * This function only produces the offset where the new clusters should be 241 * written. It updates BDRVQEDState but does not make any changes to the image 242 * file. 243 */ 244 static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n) 245 { 246 uint64_t offset = s->file_size; 247 s->file_size += n * s->header.cluster_size; 248 return offset; 249 } 250 251 QEDTable *qed_alloc_table(BDRVQEDState *s) 252 { 253 /* Honor O_DIRECT memory alignment requirements */ 254 return qemu_blockalign(s->bs, 255 s->header.cluster_size * s->header.table_size); 256 } 257 258 /** 259 * Allocate a new zeroed L2 table 260 */ 261 static CachedL2Table *qed_new_l2_table(BDRVQEDState *s) 262 { 263 CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache); 264 265 l2_table->table = qed_alloc_table(s); 266 l2_table->offset = qed_alloc_clusters(s, s->header.table_size); 267 268 memset(l2_table->table->offsets, 0, 269 s->header.cluster_size * s->header.table_size); 270 return l2_table; 271 } 272 273 static void qed_aio_next_io(void *opaque, int ret); 274 275 static void qed_plug_allocating_write_reqs(BDRVQEDState *s) 276 { 277 assert(!s->allocating_write_reqs_plugged); 278 279 s->allocating_write_reqs_plugged = true; 280 } 281 282 static void qed_unplug_allocating_write_reqs(BDRVQEDState *s) 283 { 284 QEDAIOCB *acb; 285 286 assert(s->allocating_write_reqs_plugged); 287 288 s->allocating_write_reqs_plugged = false; 289 290 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 291 if (acb) { 292 qed_aio_next_io(acb, 0); 293 } 294 } 295 296 static void qed_finish_clear_need_check(void *opaque, int ret) 297 { 298 /* Do nothing */ 299 } 300 301 static void qed_flush_after_clear_need_check(void *opaque, int ret) 302 { 303 BDRVQEDState *s = opaque; 304 305 bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s); 306 307 /* No need to wait until flush completes */ 308 qed_unplug_allocating_write_reqs(s); 309 } 310 311 static void qed_clear_need_check(void *opaque, int ret) 312 { 313 BDRVQEDState *s = opaque; 314 315 if (ret) { 316 qed_unplug_allocating_write_reqs(s); 317 return; 318 } 319 320 s->header.features &= ~QED_F_NEED_CHECK; 321 qed_write_header(s, qed_flush_after_clear_need_check, s); 322 } 323 324 static void qed_need_check_timer_cb(void *opaque) 325 { 326 BDRVQEDState *s = opaque; 327 328 /* The timer should only fire when allocating writes have drained */ 329 assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs)); 330 331 trace_qed_need_check_timer_cb(s); 332 333 qed_plug_allocating_write_reqs(s); 334 335 /* Ensure writes are on disk before clearing flag */ 336 bdrv_aio_flush(s->bs, qed_clear_need_check, s); 337 } 338 339 static void qed_start_need_check_timer(BDRVQEDState *s) 340 { 341 trace_qed_start_need_check_timer(s); 342 343 /* Use QEMU_CLOCK_VIRTUAL so we don't alter the image file while suspended for 344 * migration. 345 */ 346 timer_mod(s->need_check_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 347 get_ticks_per_sec() * QED_NEED_CHECK_TIMEOUT); 348 } 349 350 /* It's okay to call this multiple times or when no timer is started */ 351 static void qed_cancel_need_check_timer(BDRVQEDState *s) 352 { 353 trace_qed_cancel_need_check_timer(s); 354 timer_del(s->need_check_timer); 355 } 356 357 static void bdrv_qed_rebind(BlockDriverState *bs) 358 { 359 BDRVQEDState *s = bs->opaque; 360 s->bs = bs; 361 } 362 363 static void bdrv_qed_detach_aio_context(BlockDriverState *bs) 364 { 365 BDRVQEDState *s = bs->opaque; 366 367 qed_cancel_need_check_timer(s); 368 timer_free(s->need_check_timer); 369 } 370 371 static void bdrv_qed_attach_aio_context(BlockDriverState *bs, 372 AioContext *new_context) 373 { 374 BDRVQEDState *s = bs->opaque; 375 376 s->need_check_timer = aio_timer_new(new_context, 377 QEMU_CLOCK_VIRTUAL, SCALE_NS, 378 qed_need_check_timer_cb, s); 379 if (s->header.features & QED_F_NEED_CHECK) { 380 qed_start_need_check_timer(s); 381 } 382 } 383 384 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, 385 Error **errp) 386 { 387 BDRVQEDState *s = bs->opaque; 388 QEDHeader le_header; 389 int64_t file_size; 390 int ret; 391 392 s->bs = bs; 393 QSIMPLEQ_INIT(&s->allocating_write_reqs); 394 395 ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); 396 if (ret < 0) { 397 return ret; 398 } 399 qed_header_le_to_cpu(&le_header, &s->header); 400 401 if (s->header.magic != QED_MAGIC) { 402 error_setg(errp, "Image not in QED format"); 403 return -EINVAL; 404 } 405 if (s->header.features & ~QED_FEATURE_MASK) { 406 /* image uses unsupported feature bits */ 407 char buf[64]; 408 snprintf(buf, sizeof(buf), "%" PRIx64, 409 s->header.features & ~QED_FEATURE_MASK); 410 error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 411 bs->device_name, "QED", buf); 412 return -ENOTSUP; 413 } 414 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 415 return -EINVAL; 416 } 417 418 /* Round down file size to the last cluster */ 419 file_size = bdrv_getlength(bs->file); 420 if (file_size < 0) { 421 return file_size; 422 } 423 s->file_size = qed_start_of_cluster(s, file_size); 424 425 if (!qed_is_table_size_valid(s->header.table_size)) { 426 return -EINVAL; 427 } 428 if (!qed_is_image_size_valid(s->header.image_size, 429 s->header.cluster_size, 430 s->header.table_size)) { 431 return -EINVAL; 432 } 433 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 434 return -EINVAL; 435 } 436 437 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 438 sizeof(uint64_t); 439 s->l2_shift = ffs(s->header.cluster_size) - 1; 440 s->l2_mask = s->table_nelems - 1; 441 s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1; 442 443 if ((s->header.features & QED_F_BACKING_FILE)) { 444 if ((uint64_t)s->header.backing_filename_offset + 445 s->header.backing_filename_size > 446 s->header.cluster_size * s->header.header_size) { 447 return -EINVAL; 448 } 449 450 ret = qed_read_string(bs->file, s->header.backing_filename_offset, 451 s->header.backing_filename_size, bs->backing_file, 452 sizeof(bs->backing_file)); 453 if (ret < 0) { 454 return ret; 455 } 456 457 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 458 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 459 } 460 } 461 462 /* Reset unknown autoclear feature bits. This is a backwards 463 * compatibility mechanism that allows images to be opened by older 464 * programs, which "knock out" unknown feature bits. When an image is 465 * opened by a newer program again it can detect that the autoclear 466 * feature is no longer valid. 467 */ 468 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 469 !bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) { 470 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 471 472 ret = qed_write_header_sync(s); 473 if (ret) { 474 return ret; 475 } 476 477 /* From here on only known autoclear feature bits are valid */ 478 bdrv_flush(bs->file); 479 } 480 481 s->l1_table = qed_alloc_table(s); 482 qed_init_l2_cache(&s->l2_cache); 483 484 ret = qed_read_l1_table_sync(s); 485 if (ret) { 486 goto out; 487 } 488 489 /* If image was not closed cleanly, check consistency */ 490 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { 491 /* Read-only images cannot be fixed. There is no risk of corruption 492 * since write operations are not possible. Therefore, allow 493 * potentially inconsistent images to be opened read-only. This can 494 * aid data recovery from an otherwise inconsistent image. 495 */ 496 if (!bdrv_is_read_only(bs->file) && 497 !(flags & BDRV_O_INCOMING)) { 498 BdrvCheckResult result = {0}; 499 500 ret = qed_check(s, &result, true); 501 if (ret) { 502 goto out; 503 } 504 } 505 } 506 507 bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); 508 509 out: 510 if (ret) { 511 qed_free_l2_cache(&s->l2_cache); 512 qemu_vfree(s->l1_table); 513 } 514 return ret; 515 } 516 517 static void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp) 518 { 519 BDRVQEDState *s = bs->opaque; 520 521 bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS; 522 } 523 524 /* We have nothing to do for QED reopen, stubs just return 525 * success */ 526 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 527 BlockReopenQueue *queue, Error **errp) 528 { 529 return 0; 530 } 531 532 static void bdrv_qed_close(BlockDriverState *bs) 533 { 534 BDRVQEDState *s = bs->opaque; 535 536 bdrv_qed_detach_aio_context(bs); 537 538 /* Ensure writes reach stable storage */ 539 bdrv_flush(bs->file); 540 541 /* Clean shutdown, no check required on next open */ 542 if (s->header.features & QED_F_NEED_CHECK) { 543 s->header.features &= ~QED_F_NEED_CHECK; 544 qed_write_header_sync(s); 545 } 546 547 qed_free_l2_cache(&s->l2_cache); 548 qemu_vfree(s->l1_table); 549 } 550 551 static int qed_create(const char *filename, uint32_t cluster_size, 552 uint64_t image_size, uint32_t table_size, 553 const char *backing_file, const char *backing_fmt, 554 QemuOpts *opts, Error **errp) 555 { 556 QEDHeader header = { 557 .magic = QED_MAGIC, 558 .cluster_size = cluster_size, 559 .table_size = table_size, 560 .header_size = 1, 561 .features = 0, 562 .compat_features = 0, 563 .l1_table_offset = cluster_size, 564 .image_size = image_size, 565 }; 566 QEDHeader le_header; 567 uint8_t *l1_table = NULL; 568 size_t l1_size = header.cluster_size * header.table_size; 569 Error *local_err = NULL; 570 int ret = 0; 571 BlockDriverState *bs; 572 573 ret = bdrv_create_file(filename, opts, &local_err); 574 if (ret < 0) { 575 error_propagate(errp, local_err); 576 return ret; 577 } 578 579 bs = NULL; 580 ret = bdrv_open(&bs, filename, NULL, NULL, 581 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, NULL, 582 &local_err); 583 if (ret < 0) { 584 error_propagate(errp, local_err); 585 return ret; 586 } 587 588 /* File must start empty and grow, check truncate is supported */ 589 ret = bdrv_truncate(bs, 0); 590 if (ret < 0) { 591 goto out; 592 } 593 594 if (backing_file) { 595 header.features |= QED_F_BACKING_FILE; 596 header.backing_filename_offset = sizeof(le_header); 597 header.backing_filename_size = strlen(backing_file); 598 599 if (qed_fmt_is_raw(backing_fmt)) { 600 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 601 } 602 } 603 604 qed_header_cpu_to_le(&header, &le_header); 605 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); 606 if (ret < 0) { 607 goto out; 608 } 609 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file, 610 header.backing_filename_size); 611 if (ret < 0) { 612 goto out; 613 } 614 615 l1_table = g_malloc0(l1_size); 616 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size); 617 if (ret < 0) { 618 goto out; 619 } 620 621 ret = 0; /* success */ 622 out: 623 g_free(l1_table); 624 bdrv_unref(bs); 625 return ret; 626 } 627 628 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 629 { 630 uint64_t image_size = 0; 631 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 632 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 633 char *backing_file = NULL; 634 char *backing_fmt = NULL; 635 int ret; 636 637 image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 638 BDRV_SECTOR_SIZE); 639 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 640 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 641 cluster_size = qemu_opt_get_size_del(opts, 642 BLOCK_OPT_CLUSTER_SIZE, 643 QED_DEFAULT_CLUSTER_SIZE); 644 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 645 QED_DEFAULT_TABLE_SIZE); 646 647 if (!qed_is_cluster_size_valid(cluster_size)) { 648 error_setg(errp, "QED cluster size must be within range [%u, %u] " 649 "and power of 2", 650 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 651 ret = -EINVAL; 652 goto finish; 653 } 654 if (!qed_is_table_size_valid(table_size)) { 655 error_setg(errp, "QED table size must be within range [%u, %u] " 656 "and power of 2", 657 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 658 ret = -EINVAL; 659 goto finish; 660 } 661 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 662 error_setg(errp, "QED image size must be a non-zero multiple of " 663 "cluster size and less than %" PRIu64 " bytes", 664 qed_max_image_size(cluster_size, table_size)); 665 ret = -EINVAL; 666 goto finish; 667 } 668 669 ret = qed_create(filename, cluster_size, image_size, table_size, 670 backing_file, backing_fmt, opts, errp); 671 672 finish: 673 g_free(backing_file); 674 g_free(backing_fmt); 675 return ret; 676 } 677 678 typedef struct { 679 BlockDriverState *bs; 680 Coroutine *co; 681 uint64_t pos; 682 int64_t status; 683 int *pnum; 684 } QEDIsAllocatedCB; 685 686 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 687 { 688 QEDIsAllocatedCB *cb = opaque; 689 BDRVQEDState *s = cb->bs->opaque; 690 *cb->pnum = len / BDRV_SECTOR_SIZE; 691 switch (ret) { 692 case QED_CLUSTER_FOUND: 693 offset |= qed_offset_into_cluster(s, cb->pos); 694 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 695 break; 696 case QED_CLUSTER_ZERO: 697 cb->status = BDRV_BLOCK_ZERO; 698 break; 699 case QED_CLUSTER_L2: 700 case QED_CLUSTER_L1: 701 cb->status = 0; 702 break; 703 default: 704 assert(ret < 0); 705 cb->status = ret; 706 break; 707 } 708 709 if (cb->co) { 710 qemu_coroutine_enter(cb->co, NULL); 711 } 712 } 713 714 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 715 int64_t sector_num, 716 int nb_sectors, int *pnum) 717 { 718 BDRVQEDState *s = bs->opaque; 719 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 720 QEDIsAllocatedCB cb = { 721 .bs = bs, 722 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 723 .status = BDRV_BLOCK_OFFSET_MASK, 724 .pnum = pnum, 725 }; 726 QEDRequest request = { .l2_table = NULL }; 727 728 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 729 730 /* Now sleep if the callback wasn't invoked immediately */ 731 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 732 cb.co = qemu_coroutine_self(); 733 qemu_coroutine_yield(); 734 } 735 736 qed_unref_l2_cache_entry(request.l2_table); 737 738 return cb.status; 739 } 740 741 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 742 { 743 return acb->common.bs->opaque; 744 } 745 746 /** 747 * Read from the backing file or zero-fill if no backing file 748 * 749 * @s: QED state 750 * @pos: Byte position in device 751 * @qiov: Destination I/O vector 752 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 753 * @cb: Completion function 754 * @opaque: User data for completion function 755 * 756 * This function reads qiov->size bytes starting at pos from the backing file. 757 * If there is no backing file then zeroes are read. 758 */ 759 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 760 QEMUIOVector *qiov, 761 QEMUIOVector **backing_qiov, 762 BlockDriverCompletionFunc *cb, void *opaque) 763 { 764 uint64_t backing_length = 0; 765 size_t size; 766 767 /* If there is a backing file, get its length. Treat the absence of a 768 * backing file like a zero length backing file. 769 */ 770 if (s->bs->backing_hd) { 771 int64_t l = bdrv_getlength(s->bs->backing_hd); 772 if (l < 0) { 773 cb(opaque, l); 774 return; 775 } 776 backing_length = l; 777 } 778 779 /* Zero all sectors if reading beyond the end of the backing file */ 780 if (pos >= backing_length || 781 pos + qiov->size > backing_length) { 782 qemu_iovec_memset(qiov, 0, 0, qiov->size); 783 } 784 785 /* Complete now if there are no backing file sectors to read */ 786 if (pos >= backing_length) { 787 cb(opaque, 0); 788 return; 789 } 790 791 /* If the read straddles the end of the backing file, shorten it */ 792 size = MIN((uint64_t)backing_length - pos, qiov->size); 793 794 assert(*backing_qiov == NULL); 795 *backing_qiov = g_new(QEMUIOVector, 1); 796 qemu_iovec_init(*backing_qiov, qiov->niov); 797 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 798 799 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 800 bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE, 801 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 802 } 803 804 typedef struct { 805 GenericCB gencb; 806 BDRVQEDState *s; 807 QEMUIOVector qiov; 808 QEMUIOVector *backing_qiov; 809 struct iovec iov; 810 uint64_t offset; 811 } CopyFromBackingFileCB; 812 813 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 814 { 815 CopyFromBackingFileCB *copy_cb = opaque; 816 qemu_vfree(copy_cb->iov.iov_base); 817 gencb_complete(©_cb->gencb, ret); 818 } 819 820 static void qed_copy_from_backing_file_write(void *opaque, int ret) 821 { 822 CopyFromBackingFileCB *copy_cb = opaque; 823 BDRVQEDState *s = copy_cb->s; 824 825 if (copy_cb->backing_qiov) { 826 qemu_iovec_destroy(copy_cb->backing_qiov); 827 g_free(copy_cb->backing_qiov); 828 copy_cb->backing_qiov = NULL; 829 } 830 831 if (ret) { 832 qed_copy_from_backing_file_cb(copy_cb, ret); 833 return; 834 } 835 836 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 837 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 838 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 839 qed_copy_from_backing_file_cb, copy_cb); 840 } 841 842 /** 843 * Copy data from backing file into the image 844 * 845 * @s: QED state 846 * @pos: Byte position in device 847 * @len: Number of bytes 848 * @offset: Byte offset in image file 849 * @cb: Completion function 850 * @opaque: User data for completion function 851 */ 852 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 853 uint64_t len, uint64_t offset, 854 BlockDriverCompletionFunc *cb, 855 void *opaque) 856 { 857 CopyFromBackingFileCB *copy_cb; 858 859 /* Skip copy entirely if there is no work to do */ 860 if (len == 0) { 861 cb(opaque, 0); 862 return; 863 } 864 865 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 866 copy_cb->s = s; 867 copy_cb->offset = offset; 868 copy_cb->backing_qiov = NULL; 869 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 870 copy_cb->iov.iov_len = len; 871 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 872 873 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 874 qed_copy_from_backing_file_write, copy_cb); 875 } 876 877 /** 878 * Link one or more contiguous clusters into a table 879 * 880 * @s: QED state 881 * @table: L2 table 882 * @index: First cluster index 883 * @n: Number of contiguous clusters 884 * @cluster: First cluster offset 885 * 886 * The cluster offset may be an allocated byte offset in the image file, the 887 * zero cluster marker, or the unallocated cluster marker. 888 */ 889 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 890 unsigned int n, uint64_t cluster) 891 { 892 int i; 893 for (i = index; i < index + n; i++) { 894 table->offsets[i] = cluster; 895 if (!qed_offset_is_unalloc_cluster(cluster) && 896 !qed_offset_is_zero_cluster(cluster)) { 897 cluster += s->header.cluster_size; 898 } 899 } 900 } 901 902 static void qed_aio_complete_bh(void *opaque) 903 { 904 QEDAIOCB *acb = opaque; 905 BlockDriverCompletionFunc *cb = acb->common.cb; 906 void *user_opaque = acb->common.opaque; 907 int ret = acb->bh_ret; 908 909 qemu_bh_delete(acb->bh); 910 qemu_aio_unref(acb); 911 912 /* Invoke callback */ 913 cb(user_opaque, ret); 914 } 915 916 static void qed_aio_complete(QEDAIOCB *acb, int ret) 917 { 918 BDRVQEDState *s = acb_to_s(acb); 919 920 trace_qed_aio_complete(s, acb, ret); 921 922 /* Free resources */ 923 qemu_iovec_destroy(&acb->cur_qiov); 924 qed_unref_l2_cache_entry(acb->request.l2_table); 925 926 /* Free the buffer we may have allocated for zero writes */ 927 if (acb->flags & QED_AIOCB_ZERO) { 928 qemu_vfree(acb->qiov->iov[0].iov_base); 929 acb->qiov->iov[0].iov_base = NULL; 930 } 931 932 /* Arrange for a bh to invoke the completion function */ 933 acb->bh_ret = ret; 934 acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs), 935 qed_aio_complete_bh, acb); 936 qemu_bh_schedule(acb->bh); 937 938 /* Start next allocating write request waiting behind this one. Note that 939 * requests enqueue themselves when they first hit an unallocated cluster 940 * but they wait until the entire request is finished before waking up the 941 * next request in the queue. This ensures that we don't cycle through 942 * requests multiple times but rather finish one at a time completely. 943 */ 944 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 945 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 946 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 947 if (acb) { 948 qed_aio_next_io(acb, 0); 949 } else if (s->header.features & QED_F_NEED_CHECK) { 950 qed_start_need_check_timer(s); 951 } 952 } 953 } 954 955 /** 956 * Commit the current L2 table to the cache 957 */ 958 static void qed_commit_l2_update(void *opaque, int ret) 959 { 960 QEDAIOCB *acb = opaque; 961 BDRVQEDState *s = acb_to_s(acb); 962 CachedL2Table *l2_table = acb->request.l2_table; 963 uint64_t l2_offset = l2_table->offset; 964 965 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 966 967 /* This is guaranteed to succeed because we just committed the entry to the 968 * cache. 969 */ 970 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 971 assert(acb->request.l2_table != NULL); 972 973 qed_aio_next_io(opaque, ret); 974 } 975 976 /** 977 * Update L1 table with new L2 table offset and write it out 978 */ 979 static void qed_aio_write_l1_update(void *opaque, int ret) 980 { 981 QEDAIOCB *acb = opaque; 982 BDRVQEDState *s = acb_to_s(acb); 983 int index; 984 985 if (ret) { 986 qed_aio_complete(acb, ret); 987 return; 988 } 989 990 index = qed_l1_index(s, acb->cur_pos); 991 s->l1_table->offsets[index] = acb->request.l2_table->offset; 992 993 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 994 } 995 996 /** 997 * Update L2 table with new cluster offsets and write them out 998 */ 999 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 1000 { 1001 BDRVQEDState *s = acb_to_s(acb); 1002 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1003 int index; 1004 1005 if (ret) { 1006 goto err; 1007 } 1008 1009 if (need_alloc) { 1010 qed_unref_l2_cache_entry(acb->request.l2_table); 1011 acb->request.l2_table = qed_new_l2_table(s); 1012 } 1013 1014 index = qed_l2_index(s, acb->cur_pos); 1015 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1016 offset); 1017 1018 if (need_alloc) { 1019 /* Write out the whole new L2 table */ 1020 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1021 qed_aio_write_l1_update, acb); 1022 } else { 1023 /* Write out only the updated part of the L2 table */ 1024 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1025 qed_aio_next_io, acb); 1026 } 1027 return; 1028 1029 err: 1030 qed_aio_complete(acb, ret); 1031 } 1032 1033 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1034 { 1035 QEDAIOCB *acb = opaque; 1036 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1037 } 1038 1039 /** 1040 * Flush new data clusters before updating the L2 table 1041 * 1042 * This flush is necessary when a backing file is in use. A crash during an 1043 * allocating write could result in empty clusters in the image. If the write 1044 * only touched a subregion of the cluster, then backing image sectors have 1045 * been lost in the untouched region. The solution is to flush after writing a 1046 * new data cluster and before updating the L2 table. 1047 */ 1048 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1049 { 1050 QEDAIOCB *acb = opaque; 1051 BDRVQEDState *s = acb_to_s(acb); 1052 1053 if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update_cb, opaque)) { 1054 qed_aio_complete(acb, -EIO); 1055 } 1056 } 1057 1058 /** 1059 * Write data to the image file 1060 */ 1061 static void qed_aio_write_main(void *opaque, int ret) 1062 { 1063 QEDAIOCB *acb = opaque; 1064 BDRVQEDState *s = acb_to_s(acb); 1065 uint64_t offset = acb->cur_cluster + 1066 qed_offset_into_cluster(s, acb->cur_pos); 1067 BlockDriverCompletionFunc *next_fn; 1068 1069 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1070 1071 if (ret) { 1072 qed_aio_complete(acb, ret); 1073 return; 1074 } 1075 1076 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1077 next_fn = qed_aio_next_io; 1078 } else { 1079 if (s->bs->backing_hd) { 1080 next_fn = qed_aio_write_flush_before_l2_update; 1081 } else { 1082 next_fn = qed_aio_write_l2_update_cb; 1083 } 1084 } 1085 1086 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1087 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1088 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1089 next_fn, acb); 1090 } 1091 1092 /** 1093 * Populate back untouched region of new data cluster 1094 */ 1095 static void qed_aio_write_postfill(void *opaque, int ret) 1096 { 1097 QEDAIOCB *acb = opaque; 1098 BDRVQEDState *s = acb_to_s(acb); 1099 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1100 uint64_t len = 1101 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1102 uint64_t offset = acb->cur_cluster + 1103 qed_offset_into_cluster(s, acb->cur_pos) + 1104 acb->cur_qiov.size; 1105 1106 if (ret) { 1107 qed_aio_complete(acb, ret); 1108 return; 1109 } 1110 1111 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1112 qed_copy_from_backing_file(s, start, len, offset, 1113 qed_aio_write_main, acb); 1114 } 1115 1116 /** 1117 * Populate front untouched region of new data cluster 1118 */ 1119 static void qed_aio_write_prefill(void *opaque, int ret) 1120 { 1121 QEDAIOCB *acb = opaque; 1122 BDRVQEDState *s = acb_to_s(acb); 1123 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1124 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1125 1126 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1127 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1128 qed_aio_write_postfill, acb); 1129 } 1130 1131 /** 1132 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1133 */ 1134 static bool qed_should_set_need_check(BDRVQEDState *s) 1135 { 1136 /* The flush before L2 update path ensures consistency */ 1137 if (s->bs->backing_hd) { 1138 return false; 1139 } 1140 1141 return !(s->header.features & QED_F_NEED_CHECK); 1142 } 1143 1144 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1145 { 1146 QEDAIOCB *acb = opaque; 1147 1148 if (ret) { 1149 qed_aio_complete(acb, ret); 1150 return; 1151 } 1152 1153 qed_aio_write_l2_update(acb, 0, 1); 1154 } 1155 1156 /** 1157 * Write new data cluster 1158 * 1159 * @acb: Write request 1160 * @len: Length in bytes 1161 * 1162 * This path is taken when writing to previously unallocated clusters. 1163 */ 1164 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1165 { 1166 BDRVQEDState *s = acb_to_s(acb); 1167 BlockDriverCompletionFunc *cb; 1168 1169 /* Cancel timer when the first allocating request comes in */ 1170 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1171 qed_cancel_need_check_timer(s); 1172 } 1173 1174 /* Freeze this request if another allocating write is in progress */ 1175 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1176 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1177 } 1178 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1179 s->allocating_write_reqs_plugged) { 1180 return; /* wait for existing request to finish */ 1181 } 1182 1183 acb->cur_nclusters = qed_bytes_to_clusters(s, 1184 qed_offset_into_cluster(s, acb->cur_pos) + len); 1185 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1186 1187 if (acb->flags & QED_AIOCB_ZERO) { 1188 /* Skip ahead if the clusters are already zero */ 1189 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1190 qed_aio_next_io(acb, 0); 1191 return; 1192 } 1193 1194 cb = qed_aio_write_zero_cluster; 1195 } else { 1196 cb = qed_aio_write_prefill; 1197 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1198 } 1199 1200 if (qed_should_set_need_check(s)) { 1201 s->header.features |= QED_F_NEED_CHECK; 1202 qed_write_header(s, cb, acb); 1203 } else { 1204 cb(acb, 0); 1205 } 1206 } 1207 1208 /** 1209 * Write data cluster in place 1210 * 1211 * @acb: Write request 1212 * @offset: Cluster offset in bytes 1213 * @len: Length in bytes 1214 * 1215 * This path is taken when writing to already allocated clusters. 1216 */ 1217 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1218 { 1219 /* Allocate buffer for zero writes */ 1220 if (acb->flags & QED_AIOCB_ZERO) { 1221 struct iovec *iov = acb->qiov->iov; 1222 1223 if (!iov->iov_base) { 1224 iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len); 1225 if (iov->iov_base == NULL) { 1226 qed_aio_complete(acb, -ENOMEM); 1227 return; 1228 } 1229 memset(iov->iov_base, 0, iov->iov_len); 1230 } 1231 } 1232 1233 /* Calculate the I/O vector */ 1234 acb->cur_cluster = offset; 1235 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1236 1237 /* Do the actual write */ 1238 qed_aio_write_main(acb, 0); 1239 } 1240 1241 /** 1242 * Write data cluster 1243 * 1244 * @opaque: Write request 1245 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1246 * or -errno 1247 * @offset: Cluster offset in bytes 1248 * @len: Length in bytes 1249 * 1250 * Callback from qed_find_cluster(). 1251 */ 1252 static void qed_aio_write_data(void *opaque, int ret, 1253 uint64_t offset, size_t len) 1254 { 1255 QEDAIOCB *acb = opaque; 1256 1257 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1258 1259 acb->find_cluster_ret = ret; 1260 1261 switch (ret) { 1262 case QED_CLUSTER_FOUND: 1263 qed_aio_write_inplace(acb, offset, len); 1264 break; 1265 1266 case QED_CLUSTER_L2: 1267 case QED_CLUSTER_L1: 1268 case QED_CLUSTER_ZERO: 1269 qed_aio_write_alloc(acb, len); 1270 break; 1271 1272 default: 1273 qed_aio_complete(acb, ret); 1274 break; 1275 } 1276 } 1277 1278 /** 1279 * Read data cluster 1280 * 1281 * @opaque: Read request 1282 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1283 * or -errno 1284 * @offset: Cluster offset in bytes 1285 * @len: Length in bytes 1286 * 1287 * Callback from qed_find_cluster(). 1288 */ 1289 static void qed_aio_read_data(void *opaque, int ret, 1290 uint64_t offset, size_t len) 1291 { 1292 QEDAIOCB *acb = opaque; 1293 BDRVQEDState *s = acb_to_s(acb); 1294 BlockDriverState *bs = acb->common.bs; 1295 1296 /* Adjust offset into cluster */ 1297 offset += qed_offset_into_cluster(s, acb->cur_pos); 1298 1299 trace_qed_aio_read_data(s, acb, ret, offset, len); 1300 1301 if (ret < 0) { 1302 goto err; 1303 } 1304 1305 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1306 1307 /* Handle zero cluster and backing file reads */ 1308 if (ret == QED_CLUSTER_ZERO) { 1309 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1310 qed_aio_next_io(acb, 0); 1311 return; 1312 } else if (ret != QED_CLUSTER_FOUND) { 1313 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1314 &acb->backing_qiov, qed_aio_next_io, acb); 1315 return; 1316 } 1317 1318 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1319 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1320 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1321 qed_aio_next_io, acb); 1322 return; 1323 1324 err: 1325 qed_aio_complete(acb, ret); 1326 } 1327 1328 /** 1329 * Begin next I/O or complete the request 1330 */ 1331 static void qed_aio_next_io(void *opaque, int ret) 1332 { 1333 QEDAIOCB *acb = opaque; 1334 BDRVQEDState *s = acb_to_s(acb); 1335 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1336 qed_aio_write_data : qed_aio_read_data; 1337 1338 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1339 1340 if (acb->backing_qiov) { 1341 qemu_iovec_destroy(acb->backing_qiov); 1342 g_free(acb->backing_qiov); 1343 acb->backing_qiov = NULL; 1344 } 1345 1346 /* Handle I/O error */ 1347 if (ret) { 1348 qed_aio_complete(acb, ret); 1349 return; 1350 } 1351 1352 acb->qiov_offset += acb->cur_qiov.size; 1353 acb->cur_pos += acb->cur_qiov.size; 1354 qemu_iovec_reset(&acb->cur_qiov); 1355 1356 /* Complete request */ 1357 if (acb->cur_pos >= acb->end_pos) { 1358 qed_aio_complete(acb, 0); 1359 return; 1360 } 1361 1362 /* Find next cluster and start I/O */ 1363 qed_find_cluster(s, &acb->request, 1364 acb->cur_pos, acb->end_pos - acb->cur_pos, 1365 io_fn, acb); 1366 } 1367 1368 static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs, 1369 int64_t sector_num, 1370 QEMUIOVector *qiov, int nb_sectors, 1371 BlockDriverCompletionFunc *cb, 1372 void *opaque, int flags) 1373 { 1374 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1375 1376 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1377 opaque, flags); 1378 1379 acb->flags = flags; 1380 acb->qiov = qiov; 1381 acb->qiov_offset = 0; 1382 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1383 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1384 acb->backing_qiov = NULL; 1385 acb->request.l2_table = NULL; 1386 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1387 1388 /* Start request */ 1389 qed_aio_next_io(acb, 0); 1390 return &acb->common; 1391 } 1392 1393 static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1394 int64_t sector_num, 1395 QEMUIOVector *qiov, int nb_sectors, 1396 BlockDriverCompletionFunc *cb, 1397 void *opaque) 1398 { 1399 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1400 } 1401 1402 static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1403 int64_t sector_num, 1404 QEMUIOVector *qiov, int nb_sectors, 1405 BlockDriverCompletionFunc *cb, 1406 void *opaque) 1407 { 1408 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1409 opaque, QED_AIOCB_WRITE); 1410 } 1411 1412 typedef struct { 1413 Coroutine *co; 1414 int ret; 1415 bool done; 1416 } QEDWriteZeroesCB; 1417 1418 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret) 1419 { 1420 QEDWriteZeroesCB *cb = opaque; 1421 1422 cb->done = true; 1423 cb->ret = ret; 1424 if (cb->co) { 1425 qemu_coroutine_enter(cb->co, NULL); 1426 } 1427 } 1428 1429 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs, 1430 int64_t sector_num, 1431 int nb_sectors, 1432 BdrvRequestFlags flags) 1433 { 1434 BlockDriverAIOCB *blockacb; 1435 BDRVQEDState *s = bs->opaque; 1436 QEDWriteZeroesCB cb = { .done = false }; 1437 QEMUIOVector qiov; 1438 struct iovec iov; 1439 1440 /* Refuse if there are untouched backing file sectors */ 1441 if (bs->backing_hd) { 1442 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) { 1443 return -ENOTSUP; 1444 } 1445 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) { 1446 return -ENOTSUP; 1447 } 1448 } 1449 1450 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1451 * then it will be allocated during request processing. 1452 */ 1453 iov.iov_base = NULL, 1454 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE, 1455 1456 qemu_iovec_init_external(&qiov, &iov, 1); 1457 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors, 1458 qed_co_write_zeroes_cb, &cb, 1459 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1460 if (!blockacb) { 1461 return -EIO; 1462 } 1463 if (!cb.done) { 1464 cb.co = qemu_coroutine_self(); 1465 qemu_coroutine_yield(); 1466 } 1467 assert(cb.done); 1468 return cb.ret; 1469 } 1470 1471 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1472 { 1473 BDRVQEDState *s = bs->opaque; 1474 uint64_t old_image_size; 1475 int ret; 1476 1477 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1478 s->header.table_size)) { 1479 return -EINVAL; 1480 } 1481 1482 /* Shrinking is currently not supported */ 1483 if ((uint64_t)offset < s->header.image_size) { 1484 return -ENOTSUP; 1485 } 1486 1487 old_image_size = s->header.image_size; 1488 s->header.image_size = offset; 1489 ret = qed_write_header_sync(s); 1490 if (ret < 0) { 1491 s->header.image_size = old_image_size; 1492 } 1493 return ret; 1494 } 1495 1496 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1497 { 1498 BDRVQEDState *s = bs->opaque; 1499 return s->header.image_size; 1500 } 1501 1502 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1503 { 1504 BDRVQEDState *s = bs->opaque; 1505 1506 memset(bdi, 0, sizeof(*bdi)); 1507 bdi->cluster_size = s->header.cluster_size; 1508 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1509 bdi->unallocated_blocks_are_zero = true; 1510 bdi->can_write_zeroes_with_unmap = true; 1511 return 0; 1512 } 1513 1514 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1515 const char *backing_file, 1516 const char *backing_fmt) 1517 { 1518 BDRVQEDState *s = bs->opaque; 1519 QEDHeader new_header, le_header; 1520 void *buffer; 1521 size_t buffer_len, backing_file_len; 1522 int ret; 1523 1524 /* Refuse to set backing filename if unknown compat feature bits are 1525 * active. If the image uses an unknown compat feature then we may not 1526 * know the layout of data following the header structure and cannot safely 1527 * add a new string. 1528 */ 1529 if (backing_file && (s->header.compat_features & 1530 ~QED_COMPAT_FEATURE_MASK)) { 1531 return -ENOTSUP; 1532 } 1533 1534 memcpy(&new_header, &s->header, sizeof(new_header)); 1535 1536 new_header.features &= ~(QED_F_BACKING_FILE | 1537 QED_F_BACKING_FORMAT_NO_PROBE); 1538 1539 /* Adjust feature flags */ 1540 if (backing_file) { 1541 new_header.features |= QED_F_BACKING_FILE; 1542 1543 if (qed_fmt_is_raw(backing_fmt)) { 1544 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1545 } 1546 } 1547 1548 /* Calculate new header size */ 1549 backing_file_len = 0; 1550 1551 if (backing_file) { 1552 backing_file_len = strlen(backing_file); 1553 } 1554 1555 buffer_len = sizeof(new_header); 1556 new_header.backing_filename_offset = buffer_len; 1557 new_header.backing_filename_size = backing_file_len; 1558 buffer_len += backing_file_len; 1559 1560 /* Make sure we can rewrite header without failing */ 1561 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1562 return -ENOSPC; 1563 } 1564 1565 /* Prepare new header */ 1566 buffer = g_malloc(buffer_len); 1567 1568 qed_header_cpu_to_le(&new_header, &le_header); 1569 memcpy(buffer, &le_header, sizeof(le_header)); 1570 buffer_len = sizeof(le_header); 1571 1572 if (backing_file) { 1573 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1574 buffer_len += backing_file_len; 1575 } 1576 1577 /* Write new header */ 1578 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1579 g_free(buffer); 1580 if (ret == 0) { 1581 memcpy(&s->header, &new_header, sizeof(new_header)); 1582 } 1583 return ret; 1584 } 1585 1586 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1587 { 1588 BDRVQEDState *s = bs->opaque; 1589 Error *local_err = NULL; 1590 int ret; 1591 1592 bdrv_qed_close(bs); 1593 1594 bdrv_invalidate_cache(bs->file, &local_err); 1595 if (local_err) { 1596 error_propagate(errp, local_err); 1597 return; 1598 } 1599 1600 memset(s, 0, sizeof(BDRVQEDState)); 1601 ret = bdrv_qed_open(bs, NULL, bs->open_flags, &local_err); 1602 if (local_err) { 1603 error_setg(errp, "Could not reopen qed layer: %s", 1604 error_get_pretty(local_err)); 1605 error_free(local_err); 1606 return; 1607 } else if (ret < 0) { 1608 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1609 return; 1610 } 1611 } 1612 1613 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1614 BdrvCheckMode fix) 1615 { 1616 BDRVQEDState *s = bs->opaque; 1617 1618 return qed_check(s, result, !!fix); 1619 } 1620 1621 static QemuOptsList qed_create_opts = { 1622 .name = "qed-create-opts", 1623 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1624 .desc = { 1625 { 1626 .name = BLOCK_OPT_SIZE, 1627 .type = QEMU_OPT_SIZE, 1628 .help = "Virtual disk size" 1629 }, 1630 { 1631 .name = BLOCK_OPT_BACKING_FILE, 1632 .type = QEMU_OPT_STRING, 1633 .help = "File name of a base image" 1634 }, 1635 { 1636 .name = BLOCK_OPT_BACKING_FMT, 1637 .type = QEMU_OPT_STRING, 1638 .help = "Image format of the base image" 1639 }, 1640 { 1641 .name = BLOCK_OPT_CLUSTER_SIZE, 1642 .type = QEMU_OPT_SIZE, 1643 .help = "Cluster size (in bytes)", 1644 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1645 }, 1646 { 1647 .name = BLOCK_OPT_TABLE_SIZE, 1648 .type = QEMU_OPT_SIZE, 1649 .help = "L1/L2 table size (in clusters)" 1650 }, 1651 { /* end of list */ } 1652 } 1653 }; 1654 1655 static BlockDriver bdrv_qed = { 1656 .format_name = "qed", 1657 .instance_size = sizeof(BDRVQEDState), 1658 .create_opts = &qed_create_opts, 1659 .supports_backing = true, 1660 1661 .bdrv_probe = bdrv_qed_probe, 1662 .bdrv_rebind = bdrv_qed_rebind, 1663 .bdrv_open = bdrv_qed_open, 1664 .bdrv_close = bdrv_qed_close, 1665 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1666 .bdrv_create = bdrv_qed_create, 1667 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1668 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1669 .bdrv_aio_readv = bdrv_qed_aio_readv, 1670 .bdrv_aio_writev = bdrv_qed_aio_writev, 1671 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes, 1672 .bdrv_truncate = bdrv_qed_truncate, 1673 .bdrv_getlength = bdrv_qed_getlength, 1674 .bdrv_get_info = bdrv_qed_get_info, 1675 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1676 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1677 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1678 .bdrv_check = bdrv_qed_check, 1679 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1680 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1681 }; 1682 1683 static void bdrv_qed_init(void) 1684 { 1685 bdrv_register(&bdrv_qed); 1686 } 1687 1688 block_init(bdrv_qed_init); 1689