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->bs, 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->bs, 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, BlockCompletionFunc 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->bs, 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_detach_aio_context(BlockDriverState *bs) 358 { 359 BDRVQEDState *s = bs->opaque; 360 361 qed_cancel_need_check_timer(s); 362 timer_free(s->need_check_timer); 363 } 364 365 static void bdrv_qed_attach_aio_context(BlockDriverState *bs, 366 AioContext *new_context) 367 { 368 BDRVQEDState *s = bs->opaque; 369 370 s->need_check_timer = aio_timer_new(new_context, 371 QEMU_CLOCK_VIRTUAL, SCALE_NS, 372 qed_need_check_timer_cb, s); 373 if (s->header.features & QED_F_NEED_CHECK) { 374 qed_start_need_check_timer(s); 375 } 376 } 377 378 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, 379 Error **errp) 380 { 381 BDRVQEDState *s = bs->opaque; 382 QEDHeader le_header; 383 int64_t file_size; 384 int ret; 385 386 s->bs = bs; 387 QSIMPLEQ_INIT(&s->allocating_write_reqs); 388 389 ret = bdrv_pread(bs->file->bs, 0, &le_header, sizeof(le_header)); 390 if (ret < 0) { 391 return ret; 392 } 393 qed_header_le_to_cpu(&le_header, &s->header); 394 395 if (s->header.magic != QED_MAGIC) { 396 error_setg(errp, "Image not in QED format"); 397 return -EINVAL; 398 } 399 if (s->header.features & ~QED_FEATURE_MASK) { 400 /* image uses unsupported feature bits */ 401 char buf[64]; 402 snprintf(buf, sizeof(buf), "%" PRIx64, 403 s->header.features & ~QED_FEATURE_MASK); 404 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 405 bdrv_get_device_or_node_name(bs), "QED", buf); 406 return -ENOTSUP; 407 } 408 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 409 return -EINVAL; 410 } 411 412 /* Round down file size to the last cluster */ 413 file_size = bdrv_getlength(bs->file->bs); 414 if (file_size < 0) { 415 return file_size; 416 } 417 s->file_size = qed_start_of_cluster(s, file_size); 418 419 if (!qed_is_table_size_valid(s->header.table_size)) { 420 return -EINVAL; 421 } 422 if (!qed_is_image_size_valid(s->header.image_size, 423 s->header.cluster_size, 424 s->header.table_size)) { 425 return -EINVAL; 426 } 427 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 428 return -EINVAL; 429 } 430 431 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 432 sizeof(uint64_t); 433 s->l2_shift = ctz32(s->header.cluster_size); 434 s->l2_mask = s->table_nelems - 1; 435 s->l1_shift = s->l2_shift + ctz32(s->table_nelems); 436 437 /* Header size calculation must not overflow uint32_t */ 438 if (s->header.header_size > UINT32_MAX / s->header.cluster_size) { 439 return -EINVAL; 440 } 441 442 if ((s->header.features & QED_F_BACKING_FILE)) { 443 if ((uint64_t)s->header.backing_filename_offset + 444 s->header.backing_filename_size > 445 s->header.cluster_size * s->header.header_size) { 446 return -EINVAL; 447 } 448 449 ret = qed_read_string(bs->file->bs, s->header.backing_filename_offset, 450 s->header.backing_filename_size, bs->backing_file, 451 sizeof(bs->backing_file)); 452 if (ret < 0) { 453 return ret; 454 } 455 456 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 457 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 458 } 459 } 460 461 /* Reset unknown autoclear feature bits. This is a backwards 462 * compatibility mechanism that allows images to be opened by older 463 * programs, which "knock out" unknown feature bits. When an image is 464 * opened by a newer program again it can detect that the autoclear 465 * feature is no longer valid. 466 */ 467 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 468 !bdrv_is_read_only(bs->file->bs) && !(flags & BDRV_O_INCOMING)) { 469 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 470 471 ret = qed_write_header_sync(s); 472 if (ret) { 473 return ret; 474 } 475 476 /* From here on only known autoclear feature bits are valid */ 477 bdrv_flush(bs->file->bs); 478 } 479 480 s->l1_table = qed_alloc_table(s); 481 qed_init_l2_cache(&s->l2_cache); 482 483 ret = qed_read_l1_table_sync(s); 484 if (ret) { 485 goto out; 486 } 487 488 /* If image was not closed cleanly, check consistency */ 489 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { 490 /* Read-only images cannot be fixed. There is no risk of corruption 491 * since write operations are not possible. Therefore, allow 492 * potentially inconsistent images to be opened read-only. This can 493 * aid data recovery from an otherwise inconsistent image. 494 */ 495 if (!bdrv_is_read_only(bs->file->bs) && 496 !(flags & BDRV_O_INCOMING)) { 497 BdrvCheckResult result = {0}; 498 499 ret = qed_check(s, &result, true); 500 if (ret) { 501 goto out; 502 } 503 } 504 } 505 506 bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); 507 508 out: 509 if (ret) { 510 qed_free_l2_cache(&s->l2_cache); 511 qemu_vfree(s->l1_table); 512 } 513 return ret; 514 } 515 516 static void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp) 517 { 518 BDRVQEDState *s = bs->opaque; 519 520 bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS; 521 } 522 523 /* We have nothing to do for QED reopen, stubs just return 524 * success */ 525 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 526 BlockReopenQueue *queue, Error **errp) 527 { 528 return 0; 529 } 530 531 static void bdrv_qed_close(BlockDriverState *bs) 532 { 533 BDRVQEDState *s = bs->opaque; 534 535 bdrv_qed_detach_aio_context(bs); 536 537 /* Ensure writes reach stable storage */ 538 bdrv_flush(bs->file->bs); 539 540 /* Clean shutdown, no check required on next open */ 541 if (s->header.features & QED_F_NEED_CHECK) { 542 s->header.features &= ~QED_F_NEED_CHECK; 543 qed_write_header_sync(s); 544 } 545 546 qed_free_l2_cache(&s->l2_cache); 547 qemu_vfree(s->l1_table); 548 } 549 550 static int qed_create(const char *filename, uint32_t cluster_size, 551 uint64_t image_size, uint32_t table_size, 552 const char *backing_file, const char *backing_fmt, 553 QemuOpts *opts, Error **errp) 554 { 555 QEDHeader header = { 556 .magic = QED_MAGIC, 557 .cluster_size = cluster_size, 558 .table_size = table_size, 559 .header_size = 1, 560 .features = 0, 561 .compat_features = 0, 562 .l1_table_offset = cluster_size, 563 .image_size = image_size, 564 }; 565 QEDHeader le_header; 566 uint8_t *l1_table = NULL; 567 size_t l1_size = header.cluster_size * header.table_size; 568 Error *local_err = NULL; 569 int ret = 0; 570 BlockDriverState *bs; 571 572 ret = bdrv_create_file(filename, opts, &local_err); 573 if (ret < 0) { 574 error_propagate(errp, local_err); 575 return ret; 576 } 577 578 bs = NULL; 579 ret = bdrv_open(&bs, filename, NULL, NULL, 580 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, 581 &local_err); 582 if (ret < 0) { 583 error_propagate(errp, local_err); 584 return ret; 585 } 586 587 /* File must start empty and grow, check truncate is supported */ 588 ret = bdrv_truncate(bs, 0); 589 if (ret < 0) { 590 goto out; 591 } 592 593 if (backing_file) { 594 header.features |= QED_F_BACKING_FILE; 595 header.backing_filename_offset = sizeof(le_header); 596 header.backing_filename_size = strlen(backing_file); 597 598 if (qed_fmt_is_raw(backing_fmt)) { 599 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 600 } 601 } 602 603 qed_header_cpu_to_le(&header, &le_header); 604 ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header)); 605 if (ret < 0) { 606 goto out; 607 } 608 ret = bdrv_pwrite(bs, sizeof(le_header), backing_file, 609 header.backing_filename_size); 610 if (ret < 0) { 611 goto out; 612 } 613 614 l1_table = g_malloc0(l1_size); 615 ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size); 616 if (ret < 0) { 617 goto out; 618 } 619 620 ret = 0; /* success */ 621 out: 622 g_free(l1_table); 623 bdrv_unref(bs); 624 return ret; 625 } 626 627 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 628 { 629 uint64_t image_size = 0; 630 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 631 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 632 char *backing_file = NULL; 633 char *backing_fmt = NULL; 634 int ret; 635 636 image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 637 BDRV_SECTOR_SIZE); 638 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 639 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 640 cluster_size = qemu_opt_get_size_del(opts, 641 BLOCK_OPT_CLUSTER_SIZE, 642 QED_DEFAULT_CLUSTER_SIZE); 643 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 644 QED_DEFAULT_TABLE_SIZE); 645 646 if (!qed_is_cluster_size_valid(cluster_size)) { 647 error_setg(errp, "QED cluster size must be within range [%u, %u] " 648 "and power of 2", 649 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 650 ret = -EINVAL; 651 goto finish; 652 } 653 if (!qed_is_table_size_valid(table_size)) { 654 error_setg(errp, "QED table size must be within range [%u, %u] " 655 "and power of 2", 656 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 657 ret = -EINVAL; 658 goto finish; 659 } 660 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 661 error_setg(errp, "QED image size must be a non-zero multiple of " 662 "cluster size and less than %" PRIu64 " bytes", 663 qed_max_image_size(cluster_size, table_size)); 664 ret = -EINVAL; 665 goto finish; 666 } 667 668 ret = qed_create(filename, cluster_size, image_size, table_size, 669 backing_file, backing_fmt, opts, errp); 670 671 finish: 672 g_free(backing_file); 673 g_free(backing_fmt); 674 return ret; 675 } 676 677 typedef struct { 678 BlockDriverState *bs; 679 Coroutine *co; 680 uint64_t pos; 681 int64_t status; 682 int *pnum; 683 } QEDIsAllocatedCB; 684 685 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 686 { 687 QEDIsAllocatedCB *cb = opaque; 688 BDRVQEDState *s = cb->bs->opaque; 689 *cb->pnum = len / BDRV_SECTOR_SIZE; 690 switch (ret) { 691 case QED_CLUSTER_FOUND: 692 offset |= qed_offset_into_cluster(s, cb->pos); 693 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 694 break; 695 case QED_CLUSTER_ZERO: 696 cb->status = BDRV_BLOCK_ZERO; 697 break; 698 case QED_CLUSTER_L2: 699 case QED_CLUSTER_L1: 700 cb->status = 0; 701 break; 702 default: 703 assert(ret < 0); 704 cb->status = ret; 705 break; 706 } 707 708 if (cb->co) { 709 qemu_coroutine_enter(cb->co, NULL); 710 } 711 } 712 713 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 714 int64_t sector_num, 715 int nb_sectors, int *pnum) 716 { 717 BDRVQEDState *s = bs->opaque; 718 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 719 QEDIsAllocatedCB cb = { 720 .bs = bs, 721 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 722 .status = BDRV_BLOCK_OFFSET_MASK, 723 .pnum = pnum, 724 }; 725 QEDRequest request = { .l2_table = NULL }; 726 727 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 728 729 /* Now sleep if the callback wasn't invoked immediately */ 730 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 731 cb.co = qemu_coroutine_self(); 732 qemu_coroutine_yield(); 733 } 734 735 qed_unref_l2_cache_entry(request.l2_table); 736 737 return cb.status; 738 } 739 740 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 741 { 742 return acb->common.bs->opaque; 743 } 744 745 /** 746 * Read from the backing file or zero-fill if no backing file 747 * 748 * @s: QED state 749 * @pos: Byte position in device 750 * @qiov: Destination I/O vector 751 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 752 * @cb: Completion function 753 * @opaque: User data for completion function 754 * 755 * This function reads qiov->size bytes starting at pos from the backing file. 756 * If there is no backing file then zeroes are read. 757 */ 758 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 759 QEMUIOVector *qiov, 760 QEMUIOVector **backing_qiov, 761 BlockCompletionFunc *cb, void *opaque) 762 { 763 uint64_t backing_length = 0; 764 size_t size; 765 766 /* If there is a backing file, get its length. Treat the absence of a 767 * backing file like a zero length backing file. 768 */ 769 if (s->bs->backing) { 770 int64_t l = bdrv_getlength(s->bs->backing->bs); 771 if (l < 0) { 772 cb(opaque, l); 773 return; 774 } 775 backing_length = l; 776 } 777 778 /* Zero all sectors if reading beyond the end of the backing file */ 779 if (pos >= backing_length || 780 pos + qiov->size > backing_length) { 781 qemu_iovec_memset(qiov, 0, 0, qiov->size); 782 } 783 784 /* Complete now if there are no backing file sectors to read */ 785 if (pos >= backing_length) { 786 cb(opaque, 0); 787 return; 788 } 789 790 /* If the read straddles the end of the backing file, shorten it */ 791 size = MIN((uint64_t)backing_length - pos, qiov->size); 792 793 assert(*backing_qiov == NULL); 794 *backing_qiov = g_new(QEMUIOVector, 1); 795 qemu_iovec_init(*backing_qiov, qiov->niov); 796 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 797 798 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 799 bdrv_aio_readv(s->bs->backing->bs, pos / BDRV_SECTOR_SIZE, 800 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 801 } 802 803 typedef struct { 804 GenericCB gencb; 805 BDRVQEDState *s; 806 QEMUIOVector qiov; 807 QEMUIOVector *backing_qiov; 808 struct iovec iov; 809 uint64_t offset; 810 } CopyFromBackingFileCB; 811 812 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 813 { 814 CopyFromBackingFileCB *copy_cb = opaque; 815 qemu_vfree(copy_cb->iov.iov_base); 816 gencb_complete(©_cb->gencb, ret); 817 } 818 819 static void qed_copy_from_backing_file_write(void *opaque, int ret) 820 { 821 CopyFromBackingFileCB *copy_cb = opaque; 822 BDRVQEDState *s = copy_cb->s; 823 824 if (copy_cb->backing_qiov) { 825 qemu_iovec_destroy(copy_cb->backing_qiov); 826 g_free(copy_cb->backing_qiov); 827 copy_cb->backing_qiov = NULL; 828 } 829 830 if (ret) { 831 qed_copy_from_backing_file_cb(copy_cb, ret); 832 return; 833 } 834 835 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 836 bdrv_aio_writev(s->bs->file->bs, copy_cb->offset / BDRV_SECTOR_SIZE, 837 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 838 qed_copy_from_backing_file_cb, copy_cb); 839 } 840 841 /** 842 * Copy data from backing file into the image 843 * 844 * @s: QED state 845 * @pos: Byte position in device 846 * @len: Number of bytes 847 * @offset: Byte offset in image file 848 * @cb: Completion function 849 * @opaque: User data for completion function 850 */ 851 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 852 uint64_t len, uint64_t offset, 853 BlockCompletionFunc *cb, 854 void *opaque) 855 { 856 CopyFromBackingFileCB *copy_cb; 857 858 /* Skip copy entirely if there is no work to do */ 859 if (len == 0) { 860 cb(opaque, 0); 861 return; 862 } 863 864 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 865 copy_cb->s = s; 866 copy_cb->offset = offset; 867 copy_cb->backing_qiov = NULL; 868 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 869 copy_cb->iov.iov_len = len; 870 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 871 872 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 873 qed_copy_from_backing_file_write, copy_cb); 874 } 875 876 /** 877 * Link one or more contiguous clusters into a table 878 * 879 * @s: QED state 880 * @table: L2 table 881 * @index: First cluster index 882 * @n: Number of contiguous clusters 883 * @cluster: First cluster offset 884 * 885 * The cluster offset may be an allocated byte offset in the image file, the 886 * zero cluster marker, or the unallocated cluster marker. 887 */ 888 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 889 unsigned int n, uint64_t cluster) 890 { 891 int i; 892 for (i = index; i < index + n; i++) { 893 table->offsets[i] = cluster; 894 if (!qed_offset_is_unalloc_cluster(cluster) && 895 !qed_offset_is_zero_cluster(cluster)) { 896 cluster += s->header.cluster_size; 897 } 898 } 899 } 900 901 static void qed_aio_complete_bh(void *opaque) 902 { 903 QEDAIOCB *acb = opaque; 904 BlockCompletionFunc *cb = acb->common.cb; 905 void *user_opaque = acb->common.opaque; 906 int ret = acb->bh_ret; 907 908 qemu_bh_delete(acb->bh); 909 qemu_aio_unref(acb); 910 911 /* Invoke callback */ 912 cb(user_opaque, ret); 913 } 914 915 static void qed_aio_complete(QEDAIOCB *acb, int ret) 916 { 917 BDRVQEDState *s = acb_to_s(acb); 918 919 trace_qed_aio_complete(s, acb, ret); 920 921 /* Free resources */ 922 qemu_iovec_destroy(&acb->cur_qiov); 923 qed_unref_l2_cache_entry(acb->request.l2_table); 924 925 /* Free the buffer we may have allocated for zero writes */ 926 if (acb->flags & QED_AIOCB_ZERO) { 927 qemu_vfree(acb->qiov->iov[0].iov_base); 928 acb->qiov->iov[0].iov_base = NULL; 929 } 930 931 /* Arrange for a bh to invoke the completion function */ 932 acb->bh_ret = ret; 933 acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs), 934 qed_aio_complete_bh, acb); 935 qemu_bh_schedule(acb->bh); 936 937 /* Start next allocating write request waiting behind this one. Note that 938 * requests enqueue themselves when they first hit an unallocated cluster 939 * but they wait until the entire request is finished before waking up the 940 * next request in the queue. This ensures that we don't cycle through 941 * requests multiple times but rather finish one at a time completely. 942 */ 943 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 944 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 945 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 946 if (acb) { 947 qed_aio_next_io(acb, 0); 948 } else if (s->header.features & QED_F_NEED_CHECK) { 949 qed_start_need_check_timer(s); 950 } 951 } 952 } 953 954 /** 955 * Commit the current L2 table to the cache 956 */ 957 static void qed_commit_l2_update(void *opaque, int ret) 958 { 959 QEDAIOCB *acb = opaque; 960 BDRVQEDState *s = acb_to_s(acb); 961 CachedL2Table *l2_table = acb->request.l2_table; 962 uint64_t l2_offset = l2_table->offset; 963 964 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 965 966 /* This is guaranteed to succeed because we just committed the entry to the 967 * cache. 968 */ 969 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 970 assert(acb->request.l2_table != NULL); 971 972 qed_aio_next_io(opaque, ret); 973 } 974 975 /** 976 * Update L1 table with new L2 table offset and write it out 977 */ 978 static void qed_aio_write_l1_update(void *opaque, int ret) 979 { 980 QEDAIOCB *acb = opaque; 981 BDRVQEDState *s = acb_to_s(acb); 982 int index; 983 984 if (ret) { 985 qed_aio_complete(acb, ret); 986 return; 987 } 988 989 index = qed_l1_index(s, acb->cur_pos); 990 s->l1_table->offsets[index] = acb->request.l2_table->offset; 991 992 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 993 } 994 995 /** 996 * Update L2 table with new cluster offsets and write them out 997 */ 998 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 999 { 1000 BDRVQEDState *s = acb_to_s(acb); 1001 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1002 int index; 1003 1004 if (ret) { 1005 goto err; 1006 } 1007 1008 if (need_alloc) { 1009 qed_unref_l2_cache_entry(acb->request.l2_table); 1010 acb->request.l2_table = qed_new_l2_table(s); 1011 } 1012 1013 index = qed_l2_index(s, acb->cur_pos); 1014 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1015 offset); 1016 1017 if (need_alloc) { 1018 /* Write out the whole new L2 table */ 1019 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1020 qed_aio_write_l1_update, acb); 1021 } else { 1022 /* Write out only the updated part of the L2 table */ 1023 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1024 qed_aio_next_io, acb); 1025 } 1026 return; 1027 1028 err: 1029 qed_aio_complete(acb, ret); 1030 } 1031 1032 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1033 { 1034 QEDAIOCB *acb = opaque; 1035 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1036 } 1037 1038 /** 1039 * Flush new data clusters before updating the L2 table 1040 * 1041 * This flush is necessary when a backing file is in use. A crash during an 1042 * allocating write could result in empty clusters in the image. If the write 1043 * only touched a subregion of the cluster, then backing image sectors have 1044 * been lost in the untouched region. The solution is to flush after writing a 1045 * new data cluster and before updating the L2 table. 1046 */ 1047 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1048 { 1049 QEDAIOCB *acb = opaque; 1050 BDRVQEDState *s = acb_to_s(acb); 1051 1052 if (!bdrv_aio_flush(s->bs->file->bs, qed_aio_write_l2_update_cb, opaque)) { 1053 qed_aio_complete(acb, -EIO); 1054 } 1055 } 1056 1057 /** 1058 * Write data to the image file 1059 */ 1060 static void qed_aio_write_main(void *opaque, int ret) 1061 { 1062 QEDAIOCB *acb = opaque; 1063 BDRVQEDState *s = acb_to_s(acb); 1064 uint64_t offset = acb->cur_cluster + 1065 qed_offset_into_cluster(s, acb->cur_pos); 1066 BlockCompletionFunc *next_fn; 1067 1068 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1069 1070 if (ret) { 1071 qed_aio_complete(acb, ret); 1072 return; 1073 } 1074 1075 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1076 next_fn = qed_aio_next_io; 1077 } else { 1078 if (s->bs->backing) { 1079 next_fn = qed_aio_write_flush_before_l2_update; 1080 } else { 1081 next_fn = qed_aio_write_l2_update_cb; 1082 } 1083 } 1084 1085 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1086 bdrv_aio_writev(s->bs->file->bs, offset / BDRV_SECTOR_SIZE, 1087 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1088 next_fn, acb); 1089 } 1090 1091 /** 1092 * Populate back untouched region of new data cluster 1093 */ 1094 static void qed_aio_write_postfill(void *opaque, int ret) 1095 { 1096 QEDAIOCB *acb = opaque; 1097 BDRVQEDState *s = acb_to_s(acb); 1098 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1099 uint64_t len = 1100 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1101 uint64_t offset = acb->cur_cluster + 1102 qed_offset_into_cluster(s, acb->cur_pos) + 1103 acb->cur_qiov.size; 1104 1105 if (ret) { 1106 qed_aio_complete(acb, ret); 1107 return; 1108 } 1109 1110 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1111 qed_copy_from_backing_file(s, start, len, offset, 1112 qed_aio_write_main, acb); 1113 } 1114 1115 /** 1116 * Populate front untouched region of new data cluster 1117 */ 1118 static void qed_aio_write_prefill(void *opaque, int ret) 1119 { 1120 QEDAIOCB *acb = opaque; 1121 BDRVQEDState *s = acb_to_s(acb); 1122 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1123 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1124 1125 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1126 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1127 qed_aio_write_postfill, acb); 1128 } 1129 1130 /** 1131 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1132 */ 1133 static bool qed_should_set_need_check(BDRVQEDState *s) 1134 { 1135 /* The flush before L2 update path ensures consistency */ 1136 if (s->bs->backing) { 1137 return false; 1138 } 1139 1140 return !(s->header.features & QED_F_NEED_CHECK); 1141 } 1142 1143 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1144 { 1145 QEDAIOCB *acb = opaque; 1146 1147 if (ret) { 1148 qed_aio_complete(acb, ret); 1149 return; 1150 } 1151 1152 qed_aio_write_l2_update(acb, 0, 1); 1153 } 1154 1155 /** 1156 * Write new data cluster 1157 * 1158 * @acb: Write request 1159 * @len: Length in bytes 1160 * 1161 * This path is taken when writing to previously unallocated clusters. 1162 */ 1163 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1164 { 1165 BDRVQEDState *s = acb_to_s(acb); 1166 BlockCompletionFunc *cb; 1167 1168 /* Cancel timer when the first allocating request comes in */ 1169 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1170 qed_cancel_need_check_timer(s); 1171 } 1172 1173 /* Freeze this request if another allocating write is in progress */ 1174 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1175 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1176 } 1177 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1178 s->allocating_write_reqs_plugged) { 1179 return; /* wait for existing request to finish */ 1180 } 1181 1182 acb->cur_nclusters = qed_bytes_to_clusters(s, 1183 qed_offset_into_cluster(s, acb->cur_pos) + len); 1184 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1185 1186 if (acb->flags & QED_AIOCB_ZERO) { 1187 /* Skip ahead if the clusters are already zero */ 1188 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1189 qed_aio_next_io(acb, 0); 1190 return; 1191 } 1192 1193 cb = qed_aio_write_zero_cluster; 1194 } else { 1195 cb = qed_aio_write_prefill; 1196 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1197 } 1198 1199 if (qed_should_set_need_check(s)) { 1200 s->header.features |= QED_F_NEED_CHECK; 1201 qed_write_header(s, cb, acb); 1202 } else { 1203 cb(acb, 0); 1204 } 1205 } 1206 1207 /** 1208 * Write data cluster in place 1209 * 1210 * @acb: Write request 1211 * @offset: Cluster offset in bytes 1212 * @len: Length in bytes 1213 * 1214 * This path is taken when writing to already allocated clusters. 1215 */ 1216 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1217 { 1218 /* Allocate buffer for zero writes */ 1219 if (acb->flags & QED_AIOCB_ZERO) { 1220 struct iovec *iov = acb->qiov->iov; 1221 1222 if (!iov->iov_base) { 1223 iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len); 1224 if (iov->iov_base == NULL) { 1225 qed_aio_complete(acb, -ENOMEM); 1226 return; 1227 } 1228 memset(iov->iov_base, 0, iov->iov_len); 1229 } 1230 } 1231 1232 /* Calculate the I/O vector */ 1233 acb->cur_cluster = offset; 1234 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1235 1236 /* Do the actual write */ 1237 qed_aio_write_main(acb, 0); 1238 } 1239 1240 /** 1241 * Write data cluster 1242 * 1243 * @opaque: Write request 1244 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1245 * or -errno 1246 * @offset: Cluster offset in bytes 1247 * @len: Length in bytes 1248 * 1249 * Callback from qed_find_cluster(). 1250 */ 1251 static void qed_aio_write_data(void *opaque, int ret, 1252 uint64_t offset, size_t len) 1253 { 1254 QEDAIOCB *acb = opaque; 1255 1256 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1257 1258 acb->find_cluster_ret = ret; 1259 1260 switch (ret) { 1261 case QED_CLUSTER_FOUND: 1262 qed_aio_write_inplace(acb, offset, len); 1263 break; 1264 1265 case QED_CLUSTER_L2: 1266 case QED_CLUSTER_L1: 1267 case QED_CLUSTER_ZERO: 1268 qed_aio_write_alloc(acb, len); 1269 break; 1270 1271 default: 1272 qed_aio_complete(acb, ret); 1273 break; 1274 } 1275 } 1276 1277 /** 1278 * Read data cluster 1279 * 1280 * @opaque: Read request 1281 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1282 * or -errno 1283 * @offset: Cluster offset in bytes 1284 * @len: Length in bytes 1285 * 1286 * Callback from qed_find_cluster(). 1287 */ 1288 static void qed_aio_read_data(void *opaque, int ret, 1289 uint64_t offset, size_t len) 1290 { 1291 QEDAIOCB *acb = opaque; 1292 BDRVQEDState *s = acb_to_s(acb); 1293 BlockDriverState *bs = acb->common.bs; 1294 1295 /* Adjust offset into cluster */ 1296 offset += qed_offset_into_cluster(s, acb->cur_pos); 1297 1298 trace_qed_aio_read_data(s, acb, ret, offset, len); 1299 1300 if (ret < 0) { 1301 goto err; 1302 } 1303 1304 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1305 1306 /* Handle zero cluster and backing file reads */ 1307 if (ret == QED_CLUSTER_ZERO) { 1308 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1309 qed_aio_next_io(acb, 0); 1310 return; 1311 } else if (ret != QED_CLUSTER_FOUND) { 1312 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1313 &acb->backing_qiov, qed_aio_next_io, acb); 1314 return; 1315 } 1316 1317 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1318 bdrv_aio_readv(bs->file->bs, offset / BDRV_SECTOR_SIZE, 1319 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1320 qed_aio_next_io, acb); 1321 return; 1322 1323 err: 1324 qed_aio_complete(acb, ret); 1325 } 1326 1327 /** 1328 * Begin next I/O or complete the request 1329 */ 1330 static void qed_aio_next_io(void *opaque, int ret) 1331 { 1332 QEDAIOCB *acb = opaque; 1333 BDRVQEDState *s = acb_to_s(acb); 1334 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1335 qed_aio_write_data : qed_aio_read_data; 1336 1337 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1338 1339 if (acb->backing_qiov) { 1340 qemu_iovec_destroy(acb->backing_qiov); 1341 g_free(acb->backing_qiov); 1342 acb->backing_qiov = NULL; 1343 } 1344 1345 /* Handle I/O error */ 1346 if (ret) { 1347 qed_aio_complete(acb, ret); 1348 return; 1349 } 1350 1351 acb->qiov_offset += acb->cur_qiov.size; 1352 acb->cur_pos += acb->cur_qiov.size; 1353 qemu_iovec_reset(&acb->cur_qiov); 1354 1355 /* Complete request */ 1356 if (acb->cur_pos >= acb->end_pos) { 1357 qed_aio_complete(acb, 0); 1358 return; 1359 } 1360 1361 /* Find next cluster and start I/O */ 1362 qed_find_cluster(s, &acb->request, 1363 acb->cur_pos, acb->end_pos - acb->cur_pos, 1364 io_fn, acb); 1365 } 1366 1367 static BlockAIOCB *qed_aio_setup(BlockDriverState *bs, 1368 int64_t sector_num, 1369 QEMUIOVector *qiov, int nb_sectors, 1370 BlockCompletionFunc *cb, 1371 void *opaque, int flags) 1372 { 1373 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1374 1375 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1376 opaque, flags); 1377 1378 acb->flags = flags; 1379 acb->qiov = qiov; 1380 acb->qiov_offset = 0; 1381 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1382 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1383 acb->backing_qiov = NULL; 1384 acb->request.l2_table = NULL; 1385 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1386 1387 /* Start request */ 1388 qed_aio_next_io(acb, 0); 1389 return &acb->common; 1390 } 1391 1392 static BlockAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1393 int64_t sector_num, 1394 QEMUIOVector *qiov, int nb_sectors, 1395 BlockCompletionFunc *cb, 1396 void *opaque) 1397 { 1398 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1399 } 1400 1401 static BlockAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1402 int64_t sector_num, 1403 QEMUIOVector *qiov, int nb_sectors, 1404 BlockCompletionFunc *cb, 1405 void *opaque) 1406 { 1407 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1408 opaque, QED_AIOCB_WRITE); 1409 } 1410 1411 typedef struct { 1412 Coroutine *co; 1413 int ret; 1414 bool done; 1415 } QEDWriteZeroesCB; 1416 1417 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret) 1418 { 1419 QEDWriteZeroesCB *cb = opaque; 1420 1421 cb->done = true; 1422 cb->ret = ret; 1423 if (cb->co) { 1424 qemu_coroutine_enter(cb->co, NULL); 1425 } 1426 } 1427 1428 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs, 1429 int64_t sector_num, 1430 int nb_sectors, 1431 BdrvRequestFlags flags) 1432 { 1433 BlockAIOCB *blockacb; 1434 BDRVQEDState *s = bs->opaque; 1435 QEDWriteZeroesCB cb = { .done = false }; 1436 QEMUIOVector qiov; 1437 struct iovec iov; 1438 1439 /* Refuse if there are untouched backing file sectors */ 1440 if (bs->backing) { 1441 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) { 1442 return -ENOTSUP; 1443 } 1444 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) { 1445 return -ENOTSUP; 1446 } 1447 } 1448 1449 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1450 * then it will be allocated during request processing. 1451 */ 1452 iov.iov_base = NULL, 1453 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE, 1454 1455 qemu_iovec_init_external(&qiov, &iov, 1); 1456 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors, 1457 qed_co_write_zeroes_cb, &cb, 1458 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1459 if (!blockacb) { 1460 return -EIO; 1461 } 1462 if (!cb.done) { 1463 cb.co = qemu_coroutine_self(); 1464 qemu_coroutine_yield(); 1465 } 1466 assert(cb.done); 1467 return cb.ret; 1468 } 1469 1470 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1471 { 1472 BDRVQEDState *s = bs->opaque; 1473 uint64_t old_image_size; 1474 int ret; 1475 1476 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1477 s->header.table_size)) { 1478 return -EINVAL; 1479 } 1480 1481 /* Shrinking is currently not supported */ 1482 if ((uint64_t)offset < s->header.image_size) { 1483 return -ENOTSUP; 1484 } 1485 1486 old_image_size = s->header.image_size; 1487 s->header.image_size = offset; 1488 ret = qed_write_header_sync(s); 1489 if (ret < 0) { 1490 s->header.image_size = old_image_size; 1491 } 1492 return ret; 1493 } 1494 1495 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1496 { 1497 BDRVQEDState *s = bs->opaque; 1498 return s->header.image_size; 1499 } 1500 1501 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1502 { 1503 BDRVQEDState *s = bs->opaque; 1504 1505 memset(bdi, 0, sizeof(*bdi)); 1506 bdi->cluster_size = s->header.cluster_size; 1507 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1508 bdi->unallocated_blocks_are_zero = true; 1509 bdi->can_write_zeroes_with_unmap = true; 1510 return 0; 1511 } 1512 1513 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1514 const char *backing_file, 1515 const char *backing_fmt) 1516 { 1517 BDRVQEDState *s = bs->opaque; 1518 QEDHeader new_header, le_header; 1519 void *buffer; 1520 size_t buffer_len, backing_file_len; 1521 int ret; 1522 1523 /* Refuse to set backing filename if unknown compat feature bits are 1524 * active. If the image uses an unknown compat feature then we may not 1525 * know the layout of data following the header structure and cannot safely 1526 * add a new string. 1527 */ 1528 if (backing_file && (s->header.compat_features & 1529 ~QED_COMPAT_FEATURE_MASK)) { 1530 return -ENOTSUP; 1531 } 1532 1533 memcpy(&new_header, &s->header, sizeof(new_header)); 1534 1535 new_header.features &= ~(QED_F_BACKING_FILE | 1536 QED_F_BACKING_FORMAT_NO_PROBE); 1537 1538 /* Adjust feature flags */ 1539 if (backing_file) { 1540 new_header.features |= QED_F_BACKING_FILE; 1541 1542 if (qed_fmt_is_raw(backing_fmt)) { 1543 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1544 } 1545 } 1546 1547 /* Calculate new header size */ 1548 backing_file_len = 0; 1549 1550 if (backing_file) { 1551 backing_file_len = strlen(backing_file); 1552 } 1553 1554 buffer_len = sizeof(new_header); 1555 new_header.backing_filename_offset = buffer_len; 1556 new_header.backing_filename_size = backing_file_len; 1557 buffer_len += backing_file_len; 1558 1559 /* Make sure we can rewrite header without failing */ 1560 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1561 return -ENOSPC; 1562 } 1563 1564 /* Prepare new header */ 1565 buffer = g_malloc(buffer_len); 1566 1567 qed_header_cpu_to_le(&new_header, &le_header); 1568 memcpy(buffer, &le_header, sizeof(le_header)); 1569 buffer_len = sizeof(le_header); 1570 1571 if (backing_file) { 1572 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1573 buffer_len += backing_file_len; 1574 } 1575 1576 /* Write new header */ 1577 ret = bdrv_pwrite_sync(bs->file->bs, 0, buffer, buffer_len); 1578 g_free(buffer); 1579 if (ret == 0) { 1580 memcpy(&s->header, &new_header, sizeof(new_header)); 1581 } 1582 return ret; 1583 } 1584 1585 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1586 { 1587 BDRVQEDState *s = bs->opaque; 1588 Error *local_err = NULL; 1589 int ret; 1590 1591 bdrv_qed_close(bs); 1592 1593 bdrv_invalidate_cache(bs->file->bs, &local_err); 1594 if (local_err) { 1595 error_propagate(errp, local_err); 1596 return; 1597 } 1598 1599 memset(s, 0, sizeof(BDRVQEDState)); 1600 ret = bdrv_qed_open(bs, NULL, bs->open_flags, &local_err); 1601 if (local_err) { 1602 error_setg(errp, "Could not reopen qed layer: %s", 1603 error_get_pretty(local_err)); 1604 error_free(local_err); 1605 return; 1606 } else if (ret < 0) { 1607 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1608 return; 1609 } 1610 } 1611 1612 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1613 BdrvCheckMode fix) 1614 { 1615 BDRVQEDState *s = bs->opaque; 1616 1617 return qed_check(s, result, !!fix); 1618 } 1619 1620 static QemuOptsList qed_create_opts = { 1621 .name = "qed-create-opts", 1622 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1623 .desc = { 1624 { 1625 .name = BLOCK_OPT_SIZE, 1626 .type = QEMU_OPT_SIZE, 1627 .help = "Virtual disk size" 1628 }, 1629 { 1630 .name = BLOCK_OPT_BACKING_FILE, 1631 .type = QEMU_OPT_STRING, 1632 .help = "File name of a base image" 1633 }, 1634 { 1635 .name = BLOCK_OPT_BACKING_FMT, 1636 .type = QEMU_OPT_STRING, 1637 .help = "Image format of the base image" 1638 }, 1639 { 1640 .name = BLOCK_OPT_CLUSTER_SIZE, 1641 .type = QEMU_OPT_SIZE, 1642 .help = "Cluster size (in bytes)", 1643 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1644 }, 1645 { 1646 .name = BLOCK_OPT_TABLE_SIZE, 1647 .type = QEMU_OPT_SIZE, 1648 .help = "L1/L2 table size (in clusters)" 1649 }, 1650 { /* end of list */ } 1651 } 1652 }; 1653 1654 static BlockDriver bdrv_qed = { 1655 .format_name = "qed", 1656 .instance_size = sizeof(BDRVQEDState), 1657 .create_opts = &qed_create_opts, 1658 .supports_backing = true, 1659 1660 .bdrv_probe = bdrv_qed_probe, 1661 .bdrv_open = bdrv_qed_open, 1662 .bdrv_close = bdrv_qed_close, 1663 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1664 .bdrv_create = bdrv_qed_create, 1665 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1666 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1667 .bdrv_aio_readv = bdrv_qed_aio_readv, 1668 .bdrv_aio_writev = bdrv_qed_aio_writev, 1669 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes, 1670 .bdrv_truncate = bdrv_qed_truncate, 1671 .bdrv_getlength = bdrv_qed_getlength, 1672 .bdrv_get_info = bdrv_qed_get_info, 1673 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1674 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1675 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1676 .bdrv_check = bdrv_qed_check, 1677 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1678 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1679 }; 1680 1681 static void bdrv_qed_init(void) 1682 { 1683 bdrv_register(&bdrv_qed); 1684 } 1685 1686 block_init(bdrv_qed_init); 1687