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/osdep.h" 16 #include "qapi/error.h" 17 #include "qemu/timer.h" 18 #include "qemu/bswap.h" 19 #include "trace.h" 20 #include "qed.h" 21 #include "qapi/qmp/qerror.h" 22 #include "migration/migration.h" 23 #include "sysemu/block-backend.h" 24 25 static const AIOCBInfo qed_aiocb_info = { 26 .aiocb_size = sizeof(QEDAIOCB), 27 }; 28 29 static int bdrv_qed_probe(const uint8_t *buf, int buf_size, 30 const char *filename) 31 { 32 const QEDHeader *header = (const QEDHeader *)buf; 33 34 if (buf_size < sizeof(*header)) { 35 return 0; 36 } 37 if (le32_to_cpu(header->magic) != QED_MAGIC) { 38 return 0; 39 } 40 return 100; 41 } 42 43 /** 44 * Check whether an image format is raw 45 * 46 * @fmt: Backing file format, may be NULL 47 */ 48 static bool qed_fmt_is_raw(const char *fmt) 49 { 50 return fmt && strcmp(fmt, "raw") == 0; 51 } 52 53 static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu) 54 { 55 cpu->magic = le32_to_cpu(le->magic); 56 cpu->cluster_size = le32_to_cpu(le->cluster_size); 57 cpu->table_size = le32_to_cpu(le->table_size); 58 cpu->header_size = le32_to_cpu(le->header_size); 59 cpu->features = le64_to_cpu(le->features); 60 cpu->compat_features = le64_to_cpu(le->compat_features); 61 cpu->autoclear_features = le64_to_cpu(le->autoclear_features); 62 cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset); 63 cpu->image_size = le64_to_cpu(le->image_size); 64 cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset); 65 cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size); 66 } 67 68 static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le) 69 { 70 le->magic = cpu_to_le32(cpu->magic); 71 le->cluster_size = cpu_to_le32(cpu->cluster_size); 72 le->table_size = cpu_to_le32(cpu->table_size); 73 le->header_size = cpu_to_le32(cpu->header_size); 74 le->features = cpu_to_le64(cpu->features); 75 le->compat_features = cpu_to_le64(cpu->compat_features); 76 le->autoclear_features = cpu_to_le64(cpu->autoclear_features); 77 le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset); 78 le->image_size = cpu_to_le64(cpu->image_size); 79 le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset); 80 le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size); 81 } 82 83 int qed_write_header_sync(BDRVQEDState *s) 84 { 85 QEDHeader le; 86 int ret; 87 88 qed_header_cpu_to_le(&s->header, &le); 89 ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le)); 90 if (ret != sizeof(le)) { 91 return ret; 92 } 93 return 0; 94 } 95 96 typedef struct { 97 GenericCB gencb; 98 BDRVQEDState *s; 99 struct iovec iov; 100 QEMUIOVector qiov; 101 int nsectors; 102 uint8_t *buf; 103 } QEDWriteHeaderCB; 104 105 static void qed_write_header_cb(void *opaque, int ret) 106 { 107 QEDWriteHeaderCB *write_header_cb = opaque; 108 109 qemu_vfree(write_header_cb->buf); 110 gencb_complete(write_header_cb, ret); 111 } 112 113 static void qed_write_header_read_cb(void *opaque, int ret) 114 { 115 QEDWriteHeaderCB *write_header_cb = opaque; 116 BDRVQEDState *s = write_header_cb->s; 117 118 if (ret) { 119 qed_write_header_cb(write_header_cb, ret); 120 return; 121 } 122 123 /* Update header */ 124 qed_header_cpu_to_le(&s->header, (QEDHeader *)write_header_cb->buf); 125 126 bdrv_aio_writev(s->bs->file, 0, &write_header_cb->qiov, 127 write_header_cb->nsectors, qed_write_header_cb, 128 write_header_cb); 129 } 130 131 /** 132 * Update header in-place (does not rewrite backing filename or other strings) 133 * 134 * This function only updates known header fields in-place and does not affect 135 * extra data after the QED header. 136 */ 137 static void qed_write_header(BDRVQEDState *s, BlockCompletionFunc cb, 138 void *opaque) 139 { 140 /* We must write full sectors for O_DIRECT but cannot necessarily generate 141 * the data following the header if an unrecognized compat feature is 142 * active. Therefore, first read the sectors containing the header, update 143 * them, and write back. 144 */ 145 146 int nsectors = DIV_ROUND_UP(sizeof(QEDHeader), BDRV_SECTOR_SIZE); 147 size_t len = nsectors * BDRV_SECTOR_SIZE; 148 QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb), 149 cb, opaque); 150 151 write_header_cb->s = s; 152 write_header_cb->nsectors = nsectors; 153 write_header_cb->buf = qemu_blockalign(s->bs, len); 154 write_header_cb->iov.iov_base = write_header_cb->buf; 155 write_header_cb->iov.iov_len = len; 156 qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1); 157 158 bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors, 159 qed_write_header_read_cb, write_header_cb); 160 } 161 162 static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size) 163 { 164 uint64_t table_entries; 165 uint64_t l2_size; 166 167 table_entries = (table_size * cluster_size) / sizeof(uint64_t); 168 l2_size = table_entries * cluster_size; 169 170 return l2_size * table_entries; 171 } 172 173 static bool qed_is_cluster_size_valid(uint32_t cluster_size) 174 { 175 if (cluster_size < QED_MIN_CLUSTER_SIZE || 176 cluster_size > QED_MAX_CLUSTER_SIZE) { 177 return false; 178 } 179 if (cluster_size & (cluster_size - 1)) { 180 return false; /* not power of 2 */ 181 } 182 return true; 183 } 184 185 static bool qed_is_table_size_valid(uint32_t table_size) 186 { 187 if (table_size < QED_MIN_TABLE_SIZE || 188 table_size > QED_MAX_TABLE_SIZE) { 189 return false; 190 } 191 if (table_size & (table_size - 1)) { 192 return false; /* not power of 2 */ 193 } 194 return true; 195 } 196 197 static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size, 198 uint32_t table_size) 199 { 200 if (image_size % BDRV_SECTOR_SIZE != 0) { 201 return false; /* not multiple of sector size */ 202 } 203 if (image_size > qed_max_image_size(cluster_size, table_size)) { 204 return false; /* image is too large */ 205 } 206 return true; 207 } 208 209 /** 210 * Read a string of known length from the image file 211 * 212 * @file: Image file 213 * @offset: File offset to start of string, in bytes 214 * @n: String length in bytes 215 * @buf: Destination buffer 216 * @buflen: Destination buffer length in bytes 217 * @ret: 0 on success, -errno on failure 218 * 219 * The string is NUL-terminated. 220 */ 221 static int qed_read_string(BdrvChild *file, uint64_t offset, size_t n, 222 char *buf, size_t buflen) 223 { 224 int ret; 225 if (n >= buflen) { 226 return -EINVAL; 227 } 228 ret = bdrv_pread(file, offset, buf, n); 229 if (ret < 0) { 230 return ret; 231 } 232 buf[n] = '\0'; 233 return 0; 234 } 235 236 /** 237 * Allocate new clusters 238 * 239 * @s: QED state 240 * @n: Number of contiguous clusters to allocate 241 * @ret: Offset of first allocated cluster 242 * 243 * This function only produces the offset where the new clusters should be 244 * written. It updates BDRVQEDState but does not make any changes to the image 245 * file. 246 */ 247 static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n) 248 { 249 uint64_t offset = s->file_size; 250 s->file_size += n * s->header.cluster_size; 251 return offset; 252 } 253 254 QEDTable *qed_alloc_table(BDRVQEDState *s) 255 { 256 /* Honor O_DIRECT memory alignment requirements */ 257 return qemu_blockalign(s->bs, 258 s->header.cluster_size * s->header.table_size); 259 } 260 261 /** 262 * Allocate a new zeroed L2 table 263 */ 264 static CachedL2Table *qed_new_l2_table(BDRVQEDState *s) 265 { 266 CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache); 267 268 l2_table->table = qed_alloc_table(s); 269 l2_table->offset = qed_alloc_clusters(s, s->header.table_size); 270 271 memset(l2_table->table->offsets, 0, 272 s->header.cluster_size * s->header.table_size); 273 return l2_table; 274 } 275 276 static void qed_aio_next_io(QEDAIOCB *acb, int ret); 277 278 static void qed_aio_start_io(QEDAIOCB *acb) 279 { 280 qed_aio_next_io(acb, 0); 281 } 282 283 static void qed_aio_next_io_cb(void *opaque, int ret) 284 { 285 QEDAIOCB *acb = opaque; 286 287 qed_aio_next_io(acb, ret); 288 } 289 290 static void qed_plug_allocating_write_reqs(BDRVQEDState *s) 291 { 292 assert(!s->allocating_write_reqs_plugged); 293 294 s->allocating_write_reqs_plugged = true; 295 } 296 297 static void qed_unplug_allocating_write_reqs(BDRVQEDState *s) 298 { 299 QEDAIOCB *acb; 300 301 assert(s->allocating_write_reqs_plugged); 302 303 s->allocating_write_reqs_plugged = false; 304 305 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 306 if (acb) { 307 qed_aio_start_io(acb); 308 } 309 } 310 311 static void qed_finish_clear_need_check(void *opaque, int ret) 312 { 313 /* Do nothing */ 314 } 315 316 static void qed_flush_after_clear_need_check(void *opaque, int ret) 317 { 318 BDRVQEDState *s = opaque; 319 320 bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s); 321 322 /* No need to wait until flush completes */ 323 qed_unplug_allocating_write_reqs(s); 324 } 325 326 static void qed_clear_need_check(void *opaque, int ret) 327 { 328 BDRVQEDState *s = opaque; 329 330 if (ret) { 331 qed_unplug_allocating_write_reqs(s); 332 return; 333 } 334 335 s->header.features &= ~QED_F_NEED_CHECK; 336 qed_write_header(s, qed_flush_after_clear_need_check, s); 337 } 338 339 static void qed_need_check_timer_cb(void *opaque) 340 { 341 BDRVQEDState *s = opaque; 342 343 /* The timer should only fire when allocating writes have drained */ 344 assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs)); 345 346 trace_qed_need_check_timer_cb(s); 347 348 qed_acquire(s); 349 qed_plug_allocating_write_reqs(s); 350 351 /* Ensure writes are on disk before clearing flag */ 352 bdrv_aio_flush(s->bs->file->bs, qed_clear_need_check, s); 353 qed_release(s); 354 } 355 356 void qed_acquire(BDRVQEDState *s) 357 { 358 aio_context_acquire(bdrv_get_aio_context(s->bs)); 359 } 360 361 void qed_release(BDRVQEDState *s) 362 { 363 aio_context_release(bdrv_get_aio_context(s->bs)); 364 } 365 366 static void qed_start_need_check_timer(BDRVQEDState *s) 367 { 368 trace_qed_start_need_check_timer(s); 369 370 /* Use QEMU_CLOCK_VIRTUAL so we don't alter the image file while suspended for 371 * migration. 372 */ 373 timer_mod(s->need_check_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 374 NANOSECONDS_PER_SECOND * QED_NEED_CHECK_TIMEOUT); 375 } 376 377 /* It's okay to call this multiple times or when no timer is started */ 378 static void qed_cancel_need_check_timer(BDRVQEDState *s) 379 { 380 trace_qed_cancel_need_check_timer(s); 381 timer_del(s->need_check_timer); 382 } 383 384 static void bdrv_qed_detach_aio_context(BlockDriverState *bs) 385 { 386 BDRVQEDState *s = bs->opaque; 387 388 qed_cancel_need_check_timer(s); 389 timer_free(s->need_check_timer); 390 } 391 392 static void bdrv_qed_attach_aio_context(BlockDriverState *bs, 393 AioContext *new_context) 394 { 395 BDRVQEDState *s = bs->opaque; 396 397 s->need_check_timer = aio_timer_new(new_context, 398 QEMU_CLOCK_VIRTUAL, SCALE_NS, 399 qed_need_check_timer_cb, s); 400 if (s->header.features & QED_F_NEED_CHECK) { 401 qed_start_need_check_timer(s); 402 } 403 } 404 405 static void bdrv_qed_drain(BlockDriverState *bs) 406 { 407 BDRVQEDState *s = bs->opaque; 408 409 /* Fire the timer immediately in order to start doing I/O as soon as the 410 * header is flushed. 411 */ 412 if (s->need_check_timer && timer_pending(s->need_check_timer)) { 413 qed_cancel_need_check_timer(s); 414 qed_need_check_timer_cb(s); 415 } 416 } 417 418 static int bdrv_qed_do_open(BlockDriverState *bs, QDict *options, int flags, 419 Error **errp) 420 { 421 BDRVQEDState *s = bs->opaque; 422 QEDHeader le_header; 423 int64_t file_size; 424 int ret; 425 426 s->bs = bs; 427 QSIMPLEQ_INIT(&s->allocating_write_reqs); 428 429 ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header)); 430 if (ret < 0) { 431 return ret; 432 } 433 qed_header_le_to_cpu(&le_header, &s->header); 434 435 if (s->header.magic != QED_MAGIC) { 436 error_setg(errp, "Image not in QED format"); 437 return -EINVAL; 438 } 439 if (s->header.features & ~QED_FEATURE_MASK) { 440 /* image uses unsupported feature bits */ 441 error_setg(errp, "Unsupported QED features: %" PRIx64, 442 s->header.features & ~QED_FEATURE_MASK); 443 return -ENOTSUP; 444 } 445 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 446 return -EINVAL; 447 } 448 449 /* Round down file size to the last cluster */ 450 file_size = bdrv_getlength(bs->file->bs); 451 if (file_size < 0) { 452 return file_size; 453 } 454 s->file_size = qed_start_of_cluster(s, file_size); 455 456 if (!qed_is_table_size_valid(s->header.table_size)) { 457 return -EINVAL; 458 } 459 if (!qed_is_image_size_valid(s->header.image_size, 460 s->header.cluster_size, 461 s->header.table_size)) { 462 return -EINVAL; 463 } 464 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 465 return -EINVAL; 466 } 467 468 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 469 sizeof(uint64_t); 470 s->l2_shift = ctz32(s->header.cluster_size); 471 s->l2_mask = s->table_nelems - 1; 472 s->l1_shift = s->l2_shift + ctz32(s->table_nelems); 473 474 /* Header size calculation must not overflow uint32_t */ 475 if (s->header.header_size > UINT32_MAX / s->header.cluster_size) { 476 return -EINVAL; 477 } 478 479 if ((s->header.features & QED_F_BACKING_FILE)) { 480 if ((uint64_t)s->header.backing_filename_offset + 481 s->header.backing_filename_size > 482 s->header.cluster_size * s->header.header_size) { 483 return -EINVAL; 484 } 485 486 ret = qed_read_string(bs->file, s->header.backing_filename_offset, 487 s->header.backing_filename_size, bs->backing_file, 488 sizeof(bs->backing_file)); 489 if (ret < 0) { 490 return ret; 491 } 492 493 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 494 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 495 } 496 } 497 498 /* Reset unknown autoclear feature bits. This is a backwards 499 * compatibility mechanism that allows images to be opened by older 500 * programs, which "knock out" unknown feature bits. When an image is 501 * opened by a newer program again it can detect that the autoclear 502 * feature is no longer valid. 503 */ 504 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 505 !bdrv_is_read_only(bs->file->bs) && !(flags & BDRV_O_INACTIVE)) { 506 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 507 508 ret = qed_write_header_sync(s); 509 if (ret) { 510 return ret; 511 } 512 513 /* From here on only known autoclear feature bits are valid */ 514 bdrv_flush(bs->file->bs); 515 } 516 517 s->l1_table = qed_alloc_table(s); 518 qed_init_l2_cache(&s->l2_cache); 519 520 ret = qed_read_l1_table_sync(s); 521 if (ret) { 522 goto out; 523 } 524 525 /* If image was not closed cleanly, check consistency */ 526 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { 527 /* Read-only images cannot be fixed. There is no risk of corruption 528 * since write operations are not possible. Therefore, allow 529 * potentially inconsistent images to be opened read-only. This can 530 * aid data recovery from an otherwise inconsistent image. 531 */ 532 if (!bdrv_is_read_only(bs->file->bs) && 533 !(flags & BDRV_O_INACTIVE)) { 534 BdrvCheckResult result = {0}; 535 536 ret = qed_check(s, &result, true); 537 if (ret) { 538 goto out; 539 } 540 } 541 } 542 543 bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); 544 545 out: 546 if (ret) { 547 qed_free_l2_cache(&s->l2_cache); 548 qemu_vfree(s->l1_table); 549 } 550 return ret; 551 } 552 553 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, 554 Error **errp) 555 { 556 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 557 false, errp); 558 if (!bs->file) { 559 return -EINVAL; 560 } 561 562 return bdrv_qed_do_open(bs, options, flags, errp); 563 } 564 565 static void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp) 566 { 567 BDRVQEDState *s = bs->opaque; 568 569 bs->bl.pwrite_zeroes_alignment = s->header.cluster_size; 570 } 571 572 /* We have nothing to do for QED reopen, stubs just return 573 * success */ 574 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 575 BlockReopenQueue *queue, Error **errp) 576 { 577 return 0; 578 } 579 580 static void bdrv_qed_close(BlockDriverState *bs) 581 { 582 BDRVQEDState *s = bs->opaque; 583 584 bdrv_qed_detach_aio_context(bs); 585 586 /* Ensure writes reach stable storage */ 587 bdrv_flush(bs->file->bs); 588 589 /* Clean shutdown, no check required on next open */ 590 if (s->header.features & QED_F_NEED_CHECK) { 591 s->header.features &= ~QED_F_NEED_CHECK; 592 qed_write_header_sync(s); 593 } 594 595 qed_free_l2_cache(&s->l2_cache); 596 qemu_vfree(s->l1_table); 597 } 598 599 static int qed_create(const char *filename, uint32_t cluster_size, 600 uint64_t image_size, uint32_t table_size, 601 const char *backing_file, const char *backing_fmt, 602 QemuOpts *opts, Error **errp) 603 { 604 QEDHeader header = { 605 .magic = QED_MAGIC, 606 .cluster_size = cluster_size, 607 .table_size = table_size, 608 .header_size = 1, 609 .features = 0, 610 .compat_features = 0, 611 .l1_table_offset = cluster_size, 612 .image_size = image_size, 613 }; 614 QEDHeader le_header; 615 uint8_t *l1_table = NULL; 616 size_t l1_size = header.cluster_size * header.table_size; 617 Error *local_err = NULL; 618 int ret = 0; 619 BlockBackend *blk; 620 621 ret = bdrv_create_file(filename, opts, &local_err); 622 if (ret < 0) { 623 error_propagate(errp, local_err); 624 return ret; 625 } 626 627 blk = blk_new_open(filename, NULL, NULL, 628 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 629 &local_err); 630 if (blk == NULL) { 631 error_propagate(errp, local_err); 632 return -EIO; 633 } 634 635 blk_set_allow_write_beyond_eof(blk, true); 636 637 /* File must start empty and grow, check truncate is supported */ 638 ret = blk_truncate(blk, 0); 639 if (ret < 0) { 640 goto out; 641 } 642 643 if (backing_file) { 644 header.features |= QED_F_BACKING_FILE; 645 header.backing_filename_offset = sizeof(le_header); 646 header.backing_filename_size = strlen(backing_file); 647 648 if (qed_fmt_is_raw(backing_fmt)) { 649 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 650 } 651 } 652 653 qed_header_cpu_to_le(&header, &le_header); 654 ret = blk_pwrite(blk, 0, &le_header, sizeof(le_header), 0); 655 if (ret < 0) { 656 goto out; 657 } 658 ret = blk_pwrite(blk, sizeof(le_header), backing_file, 659 header.backing_filename_size, 0); 660 if (ret < 0) { 661 goto out; 662 } 663 664 l1_table = g_malloc0(l1_size); 665 ret = blk_pwrite(blk, header.l1_table_offset, l1_table, l1_size, 0); 666 if (ret < 0) { 667 goto out; 668 } 669 670 ret = 0; /* success */ 671 out: 672 g_free(l1_table); 673 blk_unref(blk); 674 return ret; 675 } 676 677 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 678 { 679 uint64_t image_size = 0; 680 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 681 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 682 char *backing_file = NULL; 683 char *backing_fmt = NULL; 684 int ret; 685 686 image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 687 BDRV_SECTOR_SIZE); 688 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 689 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 690 cluster_size = qemu_opt_get_size_del(opts, 691 BLOCK_OPT_CLUSTER_SIZE, 692 QED_DEFAULT_CLUSTER_SIZE); 693 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 694 QED_DEFAULT_TABLE_SIZE); 695 696 if (!qed_is_cluster_size_valid(cluster_size)) { 697 error_setg(errp, "QED cluster size must be within range [%u, %u] " 698 "and power of 2", 699 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 700 ret = -EINVAL; 701 goto finish; 702 } 703 if (!qed_is_table_size_valid(table_size)) { 704 error_setg(errp, "QED table size must be within range [%u, %u] " 705 "and power of 2", 706 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 707 ret = -EINVAL; 708 goto finish; 709 } 710 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 711 error_setg(errp, "QED image size must be a non-zero multiple of " 712 "cluster size and less than %" PRIu64 " bytes", 713 qed_max_image_size(cluster_size, table_size)); 714 ret = -EINVAL; 715 goto finish; 716 } 717 718 ret = qed_create(filename, cluster_size, image_size, table_size, 719 backing_file, backing_fmt, opts, errp); 720 721 finish: 722 g_free(backing_file); 723 g_free(backing_fmt); 724 return ret; 725 } 726 727 typedef struct { 728 BlockDriverState *bs; 729 Coroutine *co; 730 uint64_t pos; 731 int64_t status; 732 int *pnum; 733 BlockDriverState **file; 734 } QEDIsAllocatedCB; 735 736 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 737 { 738 QEDIsAllocatedCB *cb = opaque; 739 BDRVQEDState *s = cb->bs->opaque; 740 *cb->pnum = len / BDRV_SECTOR_SIZE; 741 switch (ret) { 742 case QED_CLUSTER_FOUND: 743 offset |= qed_offset_into_cluster(s, cb->pos); 744 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 745 *cb->file = cb->bs->file->bs; 746 break; 747 case QED_CLUSTER_ZERO: 748 cb->status = BDRV_BLOCK_ZERO; 749 break; 750 case QED_CLUSTER_L2: 751 case QED_CLUSTER_L1: 752 cb->status = 0; 753 break; 754 default: 755 assert(ret < 0); 756 cb->status = ret; 757 break; 758 } 759 760 if (cb->co) { 761 aio_co_wake(cb->co); 762 } 763 } 764 765 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 766 int64_t sector_num, 767 int nb_sectors, int *pnum, 768 BlockDriverState **file) 769 { 770 BDRVQEDState *s = bs->opaque; 771 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 772 QEDIsAllocatedCB cb = { 773 .bs = bs, 774 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 775 .status = BDRV_BLOCK_OFFSET_MASK, 776 .pnum = pnum, 777 .file = file, 778 }; 779 QEDRequest request = { .l2_table = NULL }; 780 781 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 782 783 /* Now sleep if the callback wasn't invoked immediately */ 784 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 785 cb.co = qemu_coroutine_self(); 786 qemu_coroutine_yield(); 787 } 788 789 qed_unref_l2_cache_entry(request.l2_table); 790 791 return cb.status; 792 } 793 794 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 795 { 796 return acb->common.bs->opaque; 797 } 798 799 /** 800 * Read from the backing file or zero-fill if no backing file 801 * 802 * @s: QED state 803 * @pos: Byte position in device 804 * @qiov: Destination I/O vector 805 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 806 * @cb: Completion function 807 * @opaque: User data for completion function 808 * 809 * This function reads qiov->size bytes starting at pos from the backing file. 810 * If there is no backing file then zeroes are read. 811 */ 812 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 813 QEMUIOVector *qiov, 814 QEMUIOVector **backing_qiov, 815 BlockCompletionFunc *cb, void *opaque) 816 { 817 uint64_t backing_length = 0; 818 size_t size; 819 820 /* If there is a backing file, get its length. Treat the absence of a 821 * backing file like a zero length backing file. 822 */ 823 if (s->bs->backing) { 824 int64_t l = bdrv_getlength(s->bs->backing->bs); 825 if (l < 0) { 826 cb(opaque, l); 827 return; 828 } 829 backing_length = l; 830 } 831 832 /* Zero all sectors if reading beyond the end of the backing file */ 833 if (pos >= backing_length || 834 pos + qiov->size > backing_length) { 835 qemu_iovec_memset(qiov, 0, 0, qiov->size); 836 } 837 838 /* Complete now if there are no backing file sectors to read */ 839 if (pos >= backing_length) { 840 cb(opaque, 0); 841 return; 842 } 843 844 /* If the read straddles the end of the backing file, shorten it */ 845 size = MIN((uint64_t)backing_length - pos, qiov->size); 846 847 assert(*backing_qiov == NULL); 848 *backing_qiov = g_new(QEMUIOVector, 1); 849 qemu_iovec_init(*backing_qiov, qiov->niov); 850 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 851 852 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 853 bdrv_aio_readv(s->bs->backing, pos / BDRV_SECTOR_SIZE, 854 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 855 } 856 857 typedef struct { 858 GenericCB gencb; 859 BDRVQEDState *s; 860 QEMUIOVector qiov; 861 QEMUIOVector *backing_qiov; 862 struct iovec iov; 863 uint64_t offset; 864 } CopyFromBackingFileCB; 865 866 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 867 { 868 CopyFromBackingFileCB *copy_cb = opaque; 869 qemu_vfree(copy_cb->iov.iov_base); 870 gencb_complete(©_cb->gencb, ret); 871 } 872 873 static void qed_copy_from_backing_file_write(void *opaque, int ret) 874 { 875 CopyFromBackingFileCB *copy_cb = opaque; 876 BDRVQEDState *s = copy_cb->s; 877 878 if (copy_cb->backing_qiov) { 879 qemu_iovec_destroy(copy_cb->backing_qiov); 880 g_free(copy_cb->backing_qiov); 881 copy_cb->backing_qiov = NULL; 882 } 883 884 if (ret) { 885 qed_copy_from_backing_file_cb(copy_cb, ret); 886 return; 887 } 888 889 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 890 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 891 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 892 qed_copy_from_backing_file_cb, copy_cb); 893 } 894 895 /** 896 * Copy data from backing file into the image 897 * 898 * @s: QED state 899 * @pos: Byte position in device 900 * @len: Number of bytes 901 * @offset: Byte offset in image file 902 * @cb: Completion function 903 * @opaque: User data for completion function 904 */ 905 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 906 uint64_t len, uint64_t offset, 907 BlockCompletionFunc *cb, 908 void *opaque) 909 { 910 CopyFromBackingFileCB *copy_cb; 911 912 /* Skip copy entirely if there is no work to do */ 913 if (len == 0) { 914 cb(opaque, 0); 915 return; 916 } 917 918 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 919 copy_cb->s = s; 920 copy_cb->offset = offset; 921 copy_cb->backing_qiov = NULL; 922 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 923 copy_cb->iov.iov_len = len; 924 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 925 926 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 927 qed_copy_from_backing_file_write, copy_cb); 928 } 929 930 /** 931 * Link one or more contiguous clusters into a table 932 * 933 * @s: QED state 934 * @table: L2 table 935 * @index: First cluster index 936 * @n: Number of contiguous clusters 937 * @cluster: First cluster offset 938 * 939 * The cluster offset may be an allocated byte offset in the image file, the 940 * zero cluster marker, or the unallocated cluster marker. 941 */ 942 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 943 unsigned int n, uint64_t cluster) 944 { 945 int i; 946 for (i = index; i < index + n; i++) { 947 table->offsets[i] = cluster; 948 if (!qed_offset_is_unalloc_cluster(cluster) && 949 !qed_offset_is_zero_cluster(cluster)) { 950 cluster += s->header.cluster_size; 951 } 952 } 953 } 954 955 static void qed_aio_complete_bh(void *opaque) 956 { 957 QEDAIOCB *acb = opaque; 958 BDRVQEDState *s = acb_to_s(acb); 959 BlockCompletionFunc *cb = acb->common.cb; 960 void *user_opaque = acb->common.opaque; 961 int ret = acb->bh_ret; 962 963 qemu_aio_unref(acb); 964 965 /* Invoke callback */ 966 qed_acquire(s); 967 cb(user_opaque, ret); 968 qed_release(s); 969 } 970 971 static void qed_aio_complete(QEDAIOCB *acb, int ret) 972 { 973 BDRVQEDState *s = acb_to_s(acb); 974 975 trace_qed_aio_complete(s, acb, ret); 976 977 /* Free resources */ 978 qemu_iovec_destroy(&acb->cur_qiov); 979 qed_unref_l2_cache_entry(acb->request.l2_table); 980 981 /* Free the buffer we may have allocated for zero writes */ 982 if (acb->flags & QED_AIOCB_ZERO) { 983 qemu_vfree(acb->qiov->iov[0].iov_base); 984 acb->qiov->iov[0].iov_base = NULL; 985 } 986 987 /* Arrange for a bh to invoke the completion function */ 988 acb->bh_ret = ret; 989 aio_bh_schedule_oneshot(bdrv_get_aio_context(acb->common.bs), 990 qed_aio_complete_bh, acb); 991 992 /* Start next allocating write request waiting behind this one. Note that 993 * requests enqueue themselves when they first hit an unallocated cluster 994 * but they wait until the entire request is finished before waking up the 995 * next request in the queue. This ensures that we don't cycle through 996 * requests multiple times but rather finish one at a time completely. 997 */ 998 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 999 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 1000 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 1001 if (acb) { 1002 qed_aio_start_io(acb); 1003 } else if (s->header.features & QED_F_NEED_CHECK) { 1004 qed_start_need_check_timer(s); 1005 } 1006 } 1007 } 1008 1009 /** 1010 * Commit the current L2 table to the cache 1011 */ 1012 static void qed_commit_l2_update(void *opaque, int ret) 1013 { 1014 QEDAIOCB *acb = opaque; 1015 BDRVQEDState *s = acb_to_s(acb); 1016 CachedL2Table *l2_table = acb->request.l2_table; 1017 uint64_t l2_offset = l2_table->offset; 1018 1019 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 1020 1021 /* This is guaranteed to succeed because we just committed the entry to the 1022 * cache. 1023 */ 1024 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 1025 assert(acb->request.l2_table != NULL); 1026 1027 qed_aio_next_io(acb, ret); 1028 } 1029 1030 /** 1031 * Update L1 table with new L2 table offset and write it out 1032 */ 1033 static void qed_aio_write_l1_update(void *opaque, int ret) 1034 { 1035 QEDAIOCB *acb = opaque; 1036 BDRVQEDState *s = acb_to_s(acb); 1037 int index; 1038 1039 if (ret) { 1040 qed_aio_complete(acb, ret); 1041 return; 1042 } 1043 1044 index = qed_l1_index(s, acb->cur_pos); 1045 s->l1_table->offsets[index] = acb->request.l2_table->offset; 1046 1047 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 1048 } 1049 1050 /** 1051 * Update L2 table with new cluster offsets and write them out 1052 */ 1053 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 1054 { 1055 BDRVQEDState *s = acb_to_s(acb); 1056 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1057 int index; 1058 1059 if (ret) { 1060 goto err; 1061 } 1062 1063 if (need_alloc) { 1064 qed_unref_l2_cache_entry(acb->request.l2_table); 1065 acb->request.l2_table = qed_new_l2_table(s); 1066 } 1067 1068 index = qed_l2_index(s, acb->cur_pos); 1069 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1070 offset); 1071 1072 if (need_alloc) { 1073 /* Write out the whole new L2 table */ 1074 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1075 qed_aio_write_l1_update, acb); 1076 } else { 1077 /* Write out only the updated part of the L2 table */ 1078 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1079 qed_aio_next_io_cb, acb); 1080 } 1081 return; 1082 1083 err: 1084 qed_aio_complete(acb, ret); 1085 } 1086 1087 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1088 { 1089 QEDAIOCB *acb = opaque; 1090 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1091 } 1092 1093 /** 1094 * Flush new data clusters before updating the L2 table 1095 * 1096 * This flush is necessary when a backing file is in use. A crash during an 1097 * allocating write could result in empty clusters in the image. If the write 1098 * only touched a subregion of the cluster, then backing image sectors have 1099 * been lost in the untouched region. The solution is to flush after writing a 1100 * new data cluster and before updating the L2 table. 1101 */ 1102 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1103 { 1104 QEDAIOCB *acb = opaque; 1105 BDRVQEDState *s = acb_to_s(acb); 1106 1107 if (!bdrv_aio_flush(s->bs->file->bs, qed_aio_write_l2_update_cb, opaque)) { 1108 qed_aio_complete(acb, -EIO); 1109 } 1110 } 1111 1112 /** 1113 * Write data to the image file 1114 */ 1115 static void qed_aio_write_main(void *opaque, int ret) 1116 { 1117 QEDAIOCB *acb = opaque; 1118 BDRVQEDState *s = acb_to_s(acb); 1119 uint64_t offset = acb->cur_cluster + 1120 qed_offset_into_cluster(s, acb->cur_pos); 1121 BlockCompletionFunc *next_fn; 1122 1123 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1124 1125 if (ret) { 1126 qed_aio_complete(acb, ret); 1127 return; 1128 } 1129 1130 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1131 next_fn = qed_aio_next_io_cb; 1132 } else { 1133 if (s->bs->backing) { 1134 next_fn = qed_aio_write_flush_before_l2_update; 1135 } else { 1136 next_fn = qed_aio_write_l2_update_cb; 1137 } 1138 } 1139 1140 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1141 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1142 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1143 next_fn, acb); 1144 } 1145 1146 /** 1147 * Populate back untouched region of new data cluster 1148 */ 1149 static void qed_aio_write_postfill(void *opaque, int ret) 1150 { 1151 QEDAIOCB *acb = opaque; 1152 BDRVQEDState *s = acb_to_s(acb); 1153 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1154 uint64_t len = 1155 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1156 uint64_t offset = acb->cur_cluster + 1157 qed_offset_into_cluster(s, acb->cur_pos) + 1158 acb->cur_qiov.size; 1159 1160 if (ret) { 1161 qed_aio_complete(acb, ret); 1162 return; 1163 } 1164 1165 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1166 qed_copy_from_backing_file(s, start, len, offset, 1167 qed_aio_write_main, acb); 1168 } 1169 1170 /** 1171 * Populate front untouched region of new data cluster 1172 */ 1173 static void qed_aio_write_prefill(void *opaque, int ret) 1174 { 1175 QEDAIOCB *acb = opaque; 1176 BDRVQEDState *s = acb_to_s(acb); 1177 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1178 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1179 1180 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1181 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1182 qed_aio_write_postfill, acb); 1183 } 1184 1185 /** 1186 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1187 */ 1188 static bool qed_should_set_need_check(BDRVQEDState *s) 1189 { 1190 /* The flush before L2 update path ensures consistency */ 1191 if (s->bs->backing) { 1192 return false; 1193 } 1194 1195 return !(s->header.features & QED_F_NEED_CHECK); 1196 } 1197 1198 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1199 { 1200 QEDAIOCB *acb = opaque; 1201 1202 if (ret) { 1203 qed_aio_complete(acb, ret); 1204 return; 1205 } 1206 1207 qed_aio_write_l2_update(acb, 0, 1); 1208 } 1209 1210 /** 1211 * Write new data cluster 1212 * 1213 * @acb: Write request 1214 * @len: Length in bytes 1215 * 1216 * This path is taken when writing to previously unallocated clusters. 1217 */ 1218 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1219 { 1220 BDRVQEDState *s = acb_to_s(acb); 1221 BlockCompletionFunc *cb; 1222 1223 /* Cancel timer when the first allocating request comes in */ 1224 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1225 qed_cancel_need_check_timer(s); 1226 } 1227 1228 /* Freeze this request if another allocating write is in progress */ 1229 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1230 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1231 } 1232 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1233 s->allocating_write_reqs_plugged) { 1234 return; /* wait for existing request to finish */ 1235 } 1236 1237 acb->cur_nclusters = qed_bytes_to_clusters(s, 1238 qed_offset_into_cluster(s, acb->cur_pos) + len); 1239 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1240 1241 if (acb->flags & QED_AIOCB_ZERO) { 1242 /* Skip ahead if the clusters are already zero */ 1243 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1244 qed_aio_start_io(acb); 1245 return; 1246 } 1247 1248 cb = qed_aio_write_zero_cluster; 1249 } else { 1250 cb = qed_aio_write_prefill; 1251 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1252 } 1253 1254 if (qed_should_set_need_check(s)) { 1255 s->header.features |= QED_F_NEED_CHECK; 1256 qed_write_header(s, cb, acb); 1257 } else { 1258 cb(acb, 0); 1259 } 1260 } 1261 1262 /** 1263 * Write data cluster in place 1264 * 1265 * @acb: Write request 1266 * @offset: Cluster offset in bytes 1267 * @len: Length in bytes 1268 * 1269 * This path is taken when writing to already allocated clusters. 1270 */ 1271 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1272 { 1273 /* Allocate buffer for zero writes */ 1274 if (acb->flags & QED_AIOCB_ZERO) { 1275 struct iovec *iov = acb->qiov->iov; 1276 1277 if (!iov->iov_base) { 1278 iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len); 1279 if (iov->iov_base == NULL) { 1280 qed_aio_complete(acb, -ENOMEM); 1281 return; 1282 } 1283 memset(iov->iov_base, 0, iov->iov_len); 1284 } 1285 } 1286 1287 /* Calculate the I/O vector */ 1288 acb->cur_cluster = offset; 1289 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1290 1291 /* Do the actual write */ 1292 qed_aio_write_main(acb, 0); 1293 } 1294 1295 /** 1296 * Write data cluster 1297 * 1298 * @opaque: Write request 1299 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1300 * or -errno 1301 * @offset: Cluster offset in bytes 1302 * @len: Length in bytes 1303 * 1304 * Callback from qed_find_cluster(). 1305 */ 1306 static void qed_aio_write_data(void *opaque, int ret, 1307 uint64_t offset, size_t len) 1308 { 1309 QEDAIOCB *acb = opaque; 1310 1311 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1312 1313 acb->find_cluster_ret = ret; 1314 1315 switch (ret) { 1316 case QED_CLUSTER_FOUND: 1317 qed_aio_write_inplace(acb, offset, len); 1318 break; 1319 1320 case QED_CLUSTER_L2: 1321 case QED_CLUSTER_L1: 1322 case QED_CLUSTER_ZERO: 1323 qed_aio_write_alloc(acb, len); 1324 break; 1325 1326 default: 1327 qed_aio_complete(acb, ret); 1328 break; 1329 } 1330 } 1331 1332 /** 1333 * Read data cluster 1334 * 1335 * @opaque: Read request 1336 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1337 * or -errno 1338 * @offset: Cluster offset in bytes 1339 * @len: Length in bytes 1340 * 1341 * Callback from qed_find_cluster(). 1342 */ 1343 static void qed_aio_read_data(void *opaque, int ret, 1344 uint64_t offset, size_t len) 1345 { 1346 QEDAIOCB *acb = opaque; 1347 BDRVQEDState *s = acb_to_s(acb); 1348 BlockDriverState *bs = acb->common.bs; 1349 1350 /* Adjust offset into cluster */ 1351 offset += qed_offset_into_cluster(s, acb->cur_pos); 1352 1353 trace_qed_aio_read_data(s, acb, ret, offset, len); 1354 1355 if (ret < 0) { 1356 goto err; 1357 } 1358 1359 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1360 1361 /* Handle zero cluster and backing file reads */ 1362 if (ret == QED_CLUSTER_ZERO) { 1363 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1364 qed_aio_start_io(acb); 1365 return; 1366 } else if (ret != QED_CLUSTER_FOUND) { 1367 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1368 &acb->backing_qiov, qed_aio_next_io_cb, acb); 1369 return; 1370 } 1371 1372 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1373 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1374 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1375 qed_aio_next_io_cb, acb); 1376 return; 1377 1378 err: 1379 qed_aio_complete(acb, ret); 1380 } 1381 1382 /** 1383 * Begin next I/O or complete the request 1384 */ 1385 static void qed_aio_next_io(QEDAIOCB *acb, int ret) 1386 { 1387 BDRVQEDState *s = acb_to_s(acb); 1388 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1389 qed_aio_write_data : qed_aio_read_data; 1390 1391 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1392 1393 if (acb->backing_qiov) { 1394 qemu_iovec_destroy(acb->backing_qiov); 1395 g_free(acb->backing_qiov); 1396 acb->backing_qiov = NULL; 1397 } 1398 1399 /* Handle I/O error */ 1400 if (ret) { 1401 qed_aio_complete(acb, ret); 1402 return; 1403 } 1404 1405 acb->qiov_offset += acb->cur_qiov.size; 1406 acb->cur_pos += acb->cur_qiov.size; 1407 qemu_iovec_reset(&acb->cur_qiov); 1408 1409 /* Complete request */ 1410 if (acb->cur_pos >= acb->end_pos) { 1411 qed_aio_complete(acb, 0); 1412 return; 1413 } 1414 1415 /* Find next cluster and start I/O */ 1416 qed_find_cluster(s, &acb->request, 1417 acb->cur_pos, acb->end_pos - acb->cur_pos, 1418 io_fn, acb); 1419 } 1420 1421 static BlockAIOCB *qed_aio_setup(BlockDriverState *bs, 1422 int64_t sector_num, 1423 QEMUIOVector *qiov, int nb_sectors, 1424 BlockCompletionFunc *cb, 1425 void *opaque, int flags) 1426 { 1427 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1428 1429 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1430 opaque, flags); 1431 1432 acb->flags = flags; 1433 acb->qiov = qiov; 1434 acb->qiov_offset = 0; 1435 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1436 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1437 acb->backing_qiov = NULL; 1438 acb->request.l2_table = NULL; 1439 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1440 1441 /* Start request */ 1442 qed_aio_start_io(acb); 1443 return &acb->common; 1444 } 1445 1446 static BlockAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1447 int64_t sector_num, 1448 QEMUIOVector *qiov, int nb_sectors, 1449 BlockCompletionFunc *cb, 1450 void *opaque) 1451 { 1452 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1453 } 1454 1455 static BlockAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1456 int64_t sector_num, 1457 QEMUIOVector *qiov, int nb_sectors, 1458 BlockCompletionFunc *cb, 1459 void *opaque) 1460 { 1461 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1462 opaque, QED_AIOCB_WRITE); 1463 } 1464 1465 typedef struct { 1466 Coroutine *co; 1467 int ret; 1468 bool done; 1469 } QEDWriteZeroesCB; 1470 1471 static void coroutine_fn qed_co_pwrite_zeroes_cb(void *opaque, int ret) 1472 { 1473 QEDWriteZeroesCB *cb = opaque; 1474 1475 cb->done = true; 1476 cb->ret = ret; 1477 if (cb->co) { 1478 aio_co_wake(cb->co); 1479 } 1480 } 1481 1482 static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs, 1483 int64_t offset, 1484 int count, 1485 BdrvRequestFlags flags) 1486 { 1487 BlockAIOCB *blockacb; 1488 BDRVQEDState *s = bs->opaque; 1489 QEDWriteZeroesCB cb = { .done = false }; 1490 QEMUIOVector qiov; 1491 struct iovec iov; 1492 1493 /* Fall back if the request is not aligned */ 1494 if (qed_offset_into_cluster(s, offset) || 1495 qed_offset_into_cluster(s, count)) { 1496 return -ENOTSUP; 1497 } 1498 1499 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1500 * then it will be allocated during request processing. 1501 */ 1502 iov.iov_base = NULL; 1503 iov.iov_len = count; 1504 1505 qemu_iovec_init_external(&qiov, &iov, 1); 1506 blockacb = qed_aio_setup(bs, offset >> BDRV_SECTOR_BITS, &qiov, 1507 count >> BDRV_SECTOR_BITS, 1508 qed_co_pwrite_zeroes_cb, &cb, 1509 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1510 if (!blockacb) { 1511 return -EIO; 1512 } 1513 if (!cb.done) { 1514 cb.co = qemu_coroutine_self(); 1515 qemu_coroutine_yield(); 1516 } 1517 assert(cb.done); 1518 return cb.ret; 1519 } 1520 1521 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1522 { 1523 BDRVQEDState *s = bs->opaque; 1524 uint64_t old_image_size; 1525 int ret; 1526 1527 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1528 s->header.table_size)) { 1529 return -EINVAL; 1530 } 1531 1532 /* Shrinking is currently not supported */ 1533 if ((uint64_t)offset < s->header.image_size) { 1534 return -ENOTSUP; 1535 } 1536 1537 old_image_size = s->header.image_size; 1538 s->header.image_size = offset; 1539 ret = qed_write_header_sync(s); 1540 if (ret < 0) { 1541 s->header.image_size = old_image_size; 1542 } 1543 return ret; 1544 } 1545 1546 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1547 { 1548 BDRVQEDState *s = bs->opaque; 1549 return s->header.image_size; 1550 } 1551 1552 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1553 { 1554 BDRVQEDState *s = bs->opaque; 1555 1556 memset(bdi, 0, sizeof(*bdi)); 1557 bdi->cluster_size = s->header.cluster_size; 1558 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1559 bdi->unallocated_blocks_are_zero = true; 1560 bdi->can_write_zeroes_with_unmap = true; 1561 return 0; 1562 } 1563 1564 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1565 const char *backing_file, 1566 const char *backing_fmt) 1567 { 1568 BDRVQEDState *s = bs->opaque; 1569 QEDHeader new_header, le_header; 1570 void *buffer; 1571 size_t buffer_len, backing_file_len; 1572 int ret; 1573 1574 /* Refuse to set backing filename if unknown compat feature bits are 1575 * active. If the image uses an unknown compat feature then we may not 1576 * know the layout of data following the header structure and cannot safely 1577 * add a new string. 1578 */ 1579 if (backing_file && (s->header.compat_features & 1580 ~QED_COMPAT_FEATURE_MASK)) { 1581 return -ENOTSUP; 1582 } 1583 1584 memcpy(&new_header, &s->header, sizeof(new_header)); 1585 1586 new_header.features &= ~(QED_F_BACKING_FILE | 1587 QED_F_BACKING_FORMAT_NO_PROBE); 1588 1589 /* Adjust feature flags */ 1590 if (backing_file) { 1591 new_header.features |= QED_F_BACKING_FILE; 1592 1593 if (qed_fmt_is_raw(backing_fmt)) { 1594 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1595 } 1596 } 1597 1598 /* Calculate new header size */ 1599 backing_file_len = 0; 1600 1601 if (backing_file) { 1602 backing_file_len = strlen(backing_file); 1603 } 1604 1605 buffer_len = sizeof(new_header); 1606 new_header.backing_filename_offset = buffer_len; 1607 new_header.backing_filename_size = backing_file_len; 1608 buffer_len += backing_file_len; 1609 1610 /* Make sure we can rewrite header without failing */ 1611 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1612 return -ENOSPC; 1613 } 1614 1615 /* Prepare new header */ 1616 buffer = g_malloc(buffer_len); 1617 1618 qed_header_cpu_to_le(&new_header, &le_header); 1619 memcpy(buffer, &le_header, sizeof(le_header)); 1620 buffer_len = sizeof(le_header); 1621 1622 if (backing_file) { 1623 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1624 buffer_len += backing_file_len; 1625 } 1626 1627 /* Write new header */ 1628 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1629 g_free(buffer); 1630 if (ret == 0) { 1631 memcpy(&s->header, &new_header, sizeof(new_header)); 1632 } 1633 return ret; 1634 } 1635 1636 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1637 { 1638 BDRVQEDState *s = bs->opaque; 1639 Error *local_err = NULL; 1640 int ret; 1641 1642 bdrv_qed_close(bs); 1643 1644 memset(s, 0, sizeof(BDRVQEDState)); 1645 ret = bdrv_qed_do_open(bs, NULL, bs->open_flags, &local_err); 1646 if (local_err) { 1647 error_propagate(errp, local_err); 1648 error_prepend(errp, "Could not reopen qed layer: "); 1649 return; 1650 } else if (ret < 0) { 1651 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1652 return; 1653 } 1654 } 1655 1656 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1657 BdrvCheckMode fix) 1658 { 1659 BDRVQEDState *s = bs->opaque; 1660 1661 return qed_check(s, result, !!fix); 1662 } 1663 1664 static QemuOptsList qed_create_opts = { 1665 .name = "qed-create-opts", 1666 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1667 .desc = { 1668 { 1669 .name = BLOCK_OPT_SIZE, 1670 .type = QEMU_OPT_SIZE, 1671 .help = "Virtual disk size" 1672 }, 1673 { 1674 .name = BLOCK_OPT_BACKING_FILE, 1675 .type = QEMU_OPT_STRING, 1676 .help = "File name of a base image" 1677 }, 1678 { 1679 .name = BLOCK_OPT_BACKING_FMT, 1680 .type = QEMU_OPT_STRING, 1681 .help = "Image format of the base image" 1682 }, 1683 { 1684 .name = BLOCK_OPT_CLUSTER_SIZE, 1685 .type = QEMU_OPT_SIZE, 1686 .help = "Cluster size (in bytes)", 1687 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1688 }, 1689 { 1690 .name = BLOCK_OPT_TABLE_SIZE, 1691 .type = QEMU_OPT_SIZE, 1692 .help = "L1/L2 table size (in clusters)" 1693 }, 1694 { /* end of list */ } 1695 } 1696 }; 1697 1698 static BlockDriver bdrv_qed = { 1699 .format_name = "qed", 1700 .instance_size = sizeof(BDRVQEDState), 1701 .create_opts = &qed_create_opts, 1702 .supports_backing = true, 1703 1704 .bdrv_probe = bdrv_qed_probe, 1705 .bdrv_open = bdrv_qed_open, 1706 .bdrv_close = bdrv_qed_close, 1707 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1708 .bdrv_child_perm = bdrv_format_default_perms, 1709 .bdrv_create = bdrv_qed_create, 1710 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1711 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1712 .bdrv_aio_readv = bdrv_qed_aio_readv, 1713 .bdrv_aio_writev = bdrv_qed_aio_writev, 1714 .bdrv_co_pwrite_zeroes = bdrv_qed_co_pwrite_zeroes, 1715 .bdrv_truncate = bdrv_qed_truncate, 1716 .bdrv_getlength = bdrv_qed_getlength, 1717 .bdrv_get_info = bdrv_qed_get_info, 1718 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1719 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1720 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1721 .bdrv_check = bdrv_qed_check, 1722 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1723 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1724 .bdrv_drain = bdrv_qed_drain, 1725 }; 1726 1727 static void bdrv_qed_init(void) 1728 { 1729 bdrv_register(&bdrv_qed); 1730 } 1731 1732 block_init(bdrv_qed_init); 1733