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_PROTOCOL, &local_err); 629 if (blk == NULL) { 630 error_propagate(errp, local_err); 631 return -EIO; 632 } 633 634 blk_set_allow_write_beyond_eof(blk, true); 635 636 /* File must start empty and grow, check truncate is supported */ 637 ret = blk_truncate(blk, 0); 638 if (ret < 0) { 639 goto out; 640 } 641 642 if (backing_file) { 643 header.features |= QED_F_BACKING_FILE; 644 header.backing_filename_offset = sizeof(le_header); 645 header.backing_filename_size = strlen(backing_file); 646 647 if (qed_fmt_is_raw(backing_fmt)) { 648 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 649 } 650 } 651 652 qed_header_cpu_to_le(&header, &le_header); 653 ret = blk_pwrite(blk, 0, &le_header, sizeof(le_header), 0); 654 if (ret < 0) { 655 goto out; 656 } 657 ret = blk_pwrite(blk, sizeof(le_header), backing_file, 658 header.backing_filename_size, 0); 659 if (ret < 0) { 660 goto out; 661 } 662 663 l1_table = g_malloc0(l1_size); 664 ret = blk_pwrite(blk, header.l1_table_offset, l1_table, l1_size, 0); 665 if (ret < 0) { 666 goto out; 667 } 668 669 ret = 0; /* success */ 670 out: 671 g_free(l1_table); 672 blk_unref(blk); 673 return ret; 674 } 675 676 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 677 { 678 uint64_t image_size = 0; 679 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 680 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 681 char *backing_file = NULL; 682 char *backing_fmt = NULL; 683 int ret; 684 685 image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 686 BDRV_SECTOR_SIZE); 687 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 688 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 689 cluster_size = qemu_opt_get_size_del(opts, 690 BLOCK_OPT_CLUSTER_SIZE, 691 QED_DEFAULT_CLUSTER_SIZE); 692 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 693 QED_DEFAULT_TABLE_SIZE); 694 695 if (!qed_is_cluster_size_valid(cluster_size)) { 696 error_setg(errp, "QED cluster size must be within range [%u, %u] " 697 "and power of 2", 698 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 699 ret = -EINVAL; 700 goto finish; 701 } 702 if (!qed_is_table_size_valid(table_size)) { 703 error_setg(errp, "QED table size must be within range [%u, %u] " 704 "and power of 2", 705 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 706 ret = -EINVAL; 707 goto finish; 708 } 709 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 710 error_setg(errp, "QED image size must be a non-zero multiple of " 711 "cluster size and less than %" PRIu64 " bytes", 712 qed_max_image_size(cluster_size, table_size)); 713 ret = -EINVAL; 714 goto finish; 715 } 716 717 ret = qed_create(filename, cluster_size, image_size, table_size, 718 backing_file, backing_fmt, opts, errp); 719 720 finish: 721 g_free(backing_file); 722 g_free(backing_fmt); 723 return ret; 724 } 725 726 typedef struct { 727 BlockDriverState *bs; 728 Coroutine *co; 729 uint64_t pos; 730 int64_t status; 731 int *pnum; 732 BlockDriverState **file; 733 } QEDIsAllocatedCB; 734 735 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 736 { 737 QEDIsAllocatedCB *cb = opaque; 738 BDRVQEDState *s = cb->bs->opaque; 739 *cb->pnum = len / BDRV_SECTOR_SIZE; 740 switch (ret) { 741 case QED_CLUSTER_FOUND: 742 offset |= qed_offset_into_cluster(s, cb->pos); 743 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 744 *cb->file = cb->bs->file->bs; 745 break; 746 case QED_CLUSTER_ZERO: 747 cb->status = BDRV_BLOCK_ZERO; 748 break; 749 case QED_CLUSTER_L2: 750 case QED_CLUSTER_L1: 751 cb->status = 0; 752 break; 753 default: 754 assert(ret < 0); 755 cb->status = ret; 756 break; 757 } 758 759 if (cb->co) { 760 aio_co_wake(cb->co); 761 } 762 } 763 764 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 765 int64_t sector_num, 766 int nb_sectors, int *pnum, 767 BlockDriverState **file) 768 { 769 BDRVQEDState *s = bs->opaque; 770 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 771 QEDIsAllocatedCB cb = { 772 .bs = bs, 773 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 774 .status = BDRV_BLOCK_OFFSET_MASK, 775 .pnum = pnum, 776 .file = file, 777 }; 778 QEDRequest request = { .l2_table = NULL }; 779 780 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 781 782 /* Now sleep if the callback wasn't invoked immediately */ 783 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 784 cb.co = qemu_coroutine_self(); 785 qemu_coroutine_yield(); 786 } 787 788 qed_unref_l2_cache_entry(request.l2_table); 789 790 return cb.status; 791 } 792 793 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 794 { 795 return acb->common.bs->opaque; 796 } 797 798 /** 799 * Read from the backing file or zero-fill if no backing file 800 * 801 * @s: QED state 802 * @pos: Byte position in device 803 * @qiov: Destination I/O vector 804 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 805 * @cb: Completion function 806 * @opaque: User data for completion function 807 * 808 * This function reads qiov->size bytes starting at pos from the backing file. 809 * If there is no backing file then zeroes are read. 810 */ 811 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 812 QEMUIOVector *qiov, 813 QEMUIOVector **backing_qiov, 814 BlockCompletionFunc *cb, void *opaque) 815 { 816 uint64_t backing_length = 0; 817 size_t size; 818 819 /* If there is a backing file, get its length. Treat the absence of a 820 * backing file like a zero length backing file. 821 */ 822 if (s->bs->backing) { 823 int64_t l = bdrv_getlength(s->bs->backing->bs); 824 if (l < 0) { 825 cb(opaque, l); 826 return; 827 } 828 backing_length = l; 829 } 830 831 /* Zero all sectors if reading beyond the end of the backing file */ 832 if (pos >= backing_length || 833 pos + qiov->size > backing_length) { 834 qemu_iovec_memset(qiov, 0, 0, qiov->size); 835 } 836 837 /* Complete now if there are no backing file sectors to read */ 838 if (pos >= backing_length) { 839 cb(opaque, 0); 840 return; 841 } 842 843 /* If the read straddles the end of the backing file, shorten it */ 844 size = MIN((uint64_t)backing_length - pos, qiov->size); 845 846 assert(*backing_qiov == NULL); 847 *backing_qiov = g_new(QEMUIOVector, 1); 848 qemu_iovec_init(*backing_qiov, qiov->niov); 849 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 850 851 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 852 bdrv_aio_readv(s->bs->backing, pos / BDRV_SECTOR_SIZE, 853 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 854 } 855 856 typedef struct { 857 GenericCB gencb; 858 BDRVQEDState *s; 859 QEMUIOVector qiov; 860 QEMUIOVector *backing_qiov; 861 struct iovec iov; 862 uint64_t offset; 863 } CopyFromBackingFileCB; 864 865 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 866 { 867 CopyFromBackingFileCB *copy_cb = opaque; 868 qemu_vfree(copy_cb->iov.iov_base); 869 gencb_complete(©_cb->gencb, ret); 870 } 871 872 static void qed_copy_from_backing_file_write(void *opaque, int ret) 873 { 874 CopyFromBackingFileCB *copy_cb = opaque; 875 BDRVQEDState *s = copy_cb->s; 876 877 if (copy_cb->backing_qiov) { 878 qemu_iovec_destroy(copy_cb->backing_qiov); 879 g_free(copy_cb->backing_qiov); 880 copy_cb->backing_qiov = NULL; 881 } 882 883 if (ret) { 884 qed_copy_from_backing_file_cb(copy_cb, ret); 885 return; 886 } 887 888 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 889 bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE, 890 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 891 qed_copy_from_backing_file_cb, copy_cb); 892 } 893 894 /** 895 * Copy data from backing file into the image 896 * 897 * @s: QED state 898 * @pos: Byte position in device 899 * @len: Number of bytes 900 * @offset: Byte offset in image file 901 * @cb: Completion function 902 * @opaque: User data for completion function 903 */ 904 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 905 uint64_t len, uint64_t offset, 906 BlockCompletionFunc *cb, 907 void *opaque) 908 { 909 CopyFromBackingFileCB *copy_cb; 910 911 /* Skip copy entirely if there is no work to do */ 912 if (len == 0) { 913 cb(opaque, 0); 914 return; 915 } 916 917 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 918 copy_cb->s = s; 919 copy_cb->offset = offset; 920 copy_cb->backing_qiov = NULL; 921 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 922 copy_cb->iov.iov_len = len; 923 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 924 925 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 926 qed_copy_from_backing_file_write, copy_cb); 927 } 928 929 /** 930 * Link one or more contiguous clusters into a table 931 * 932 * @s: QED state 933 * @table: L2 table 934 * @index: First cluster index 935 * @n: Number of contiguous clusters 936 * @cluster: First cluster offset 937 * 938 * The cluster offset may be an allocated byte offset in the image file, the 939 * zero cluster marker, or the unallocated cluster marker. 940 */ 941 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 942 unsigned int n, uint64_t cluster) 943 { 944 int i; 945 for (i = index; i < index + n; i++) { 946 table->offsets[i] = cluster; 947 if (!qed_offset_is_unalloc_cluster(cluster) && 948 !qed_offset_is_zero_cluster(cluster)) { 949 cluster += s->header.cluster_size; 950 } 951 } 952 } 953 954 static void qed_aio_complete_bh(void *opaque) 955 { 956 QEDAIOCB *acb = opaque; 957 BDRVQEDState *s = acb_to_s(acb); 958 BlockCompletionFunc *cb = acb->common.cb; 959 void *user_opaque = acb->common.opaque; 960 int ret = acb->bh_ret; 961 962 qemu_aio_unref(acb); 963 964 /* Invoke callback */ 965 qed_acquire(s); 966 cb(user_opaque, ret); 967 qed_release(s); 968 } 969 970 static void qed_aio_complete(QEDAIOCB *acb, int ret) 971 { 972 BDRVQEDState *s = acb_to_s(acb); 973 974 trace_qed_aio_complete(s, acb, ret); 975 976 /* Free resources */ 977 qemu_iovec_destroy(&acb->cur_qiov); 978 qed_unref_l2_cache_entry(acb->request.l2_table); 979 980 /* Free the buffer we may have allocated for zero writes */ 981 if (acb->flags & QED_AIOCB_ZERO) { 982 qemu_vfree(acb->qiov->iov[0].iov_base); 983 acb->qiov->iov[0].iov_base = NULL; 984 } 985 986 /* Arrange for a bh to invoke the completion function */ 987 acb->bh_ret = ret; 988 aio_bh_schedule_oneshot(bdrv_get_aio_context(acb->common.bs), 989 qed_aio_complete_bh, acb); 990 991 /* Start next allocating write request waiting behind this one. Note that 992 * requests enqueue themselves when they first hit an unallocated cluster 993 * but they wait until the entire request is finished before waking up the 994 * next request in the queue. This ensures that we don't cycle through 995 * requests multiple times but rather finish one at a time completely. 996 */ 997 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 998 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 999 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 1000 if (acb) { 1001 qed_aio_start_io(acb); 1002 } else if (s->header.features & QED_F_NEED_CHECK) { 1003 qed_start_need_check_timer(s); 1004 } 1005 } 1006 } 1007 1008 /** 1009 * Commit the current L2 table to the cache 1010 */ 1011 static void qed_commit_l2_update(void *opaque, int ret) 1012 { 1013 QEDAIOCB *acb = opaque; 1014 BDRVQEDState *s = acb_to_s(acb); 1015 CachedL2Table *l2_table = acb->request.l2_table; 1016 uint64_t l2_offset = l2_table->offset; 1017 1018 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 1019 1020 /* This is guaranteed to succeed because we just committed the entry to the 1021 * cache. 1022 */ 1023 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 1024 assert(acb->request.l2_table != NULL); 1025 1026 qed_aio_next_io(acb, ret); 1027 } 1028 1029 /** 1030 * Update L1 table with new L2 table offset and write it out 1031 */ 1032 static void qed_aio_write_l1_update(void *opaque, int ret) 1033 { 1034 QEDAIOCB *acb = opaque; 1035 BDRVQEDState *s = acb_to_s(acb); 1036 int index; 1037 1038 if (ret) { 1039 qed_aio_complete(acb, ret); 1040 return; 1041 } 1042 1043 index = qed_l1_index(s, acb->cur_pos); 1044 s->l1_table->offsets[index] = acb->request.l2_table->offset; 1045 1046 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 1047 } 1048 1049 /** 1050 * Update L2 table with new cluster offsets and write them out 1051 */ 1052 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 1053 { 1054 BDRVQEDState *s = acb_to_s(acb); 1055 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1056 int index; 1057 1058 if (ret) { 1059 goto err; 1060 } 1061 1062 if (need_alloc) { 1063 qed_unref_l2_cache_entry(acb->request.l2_table); 1064 acb->request.l2_table = qed_new_l2_table(s); 1065 } 1066 1067 index = qed_l2_index(s, acb->cur_pos); 1068 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1069 offset); 1070 1071 if (need_alloc) { 1072 /* Write out the whole new L2 table */ 1073 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1074 qed_aio_write_l1_update, acb); 1075 } else { 1076 /* Write out only the updated part of the L2 table */ 1077 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1078 qed_aio_next_io_cb, acb); 1079 } 1080 return; 1081 1082 err: 1083 qed_aio_complete(acb, ret); 1084 } 1085 1086 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1087 { 1088 QEDAIOCB *acb = opaque; 1089 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1090 } 1091 1092 /** 1093 * Flush new data clusters before updating the L2 table 1094 * 1095 * This flush is necessary when a backing file is in use. A crash during an 1096 * allocating write could result in empty clusters in the image. If the write 1097 * only touched a subregion of the cluster, then backing image sectors have 1098 * been lost in the untouched region. The solution is to flush after writing a 1099 * new data cluster and before updating the L2 table. 1100 */ 1101 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1102 { 1103 QEDAIOCB *acb = opaque; 1104 BDRVQEDState *s = acb_to_s(acb); 1105 1106 if (!bdrv_aio_flush(s->bs->file->bs, qed_aio_write_l2_update_cb, opaque)) { 1107 qed_aio_complete(acb, -EIO); 1108 } 1109 } 1110 1111 /** 1112 * Write data to the image file 1113 */ 1114 static void qed_aio_write_main(void *opaque, int ret) 1115 { 1116 QEDAIOCB *acb = opaque; 1117 BDRVQEDState *s = acb_to_s(acb); 1118 uint64_t offset = acb->cur_cluster + 1119 qed_offset_into_cluster(s, acb->cur_pos); 1120 BlockCompletionFunc *next_fn; 1121 1122 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1123 1124 if (ret) { 1125 qed_aio_complete(acb, ret); 1126 return; 1127 } 1128 1129 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1130 next_fn = qed_aio_next_io_cb; 1131 } else { 1132 if (s->bs->backing) { 1133 next_fn = qed_aio_write_flush_before_l2_update; 1134 } else { 1135 next_fn = qed_aio_write_l2_update_cb; 1136 } 1137 } 1138 1139 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1140 bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE, 1141 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1142 next_fn, acb); 1143 } 1144 1145 /** 1146 * Populate back untouched region of new data cluster 1147 */ 1148 static void qed_aio_write_postfill(void *opaque, int ret) 1149 { 1150 QEDAIOCB *acb = opaque; 1151 BDRVQEDState *s = acb_to_s(acb); 1152 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1153 uint64_t len = 1154 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1155 uint64_t offset = acb->cur_cluster + 1156 qed_offset_into_cluster(s, acb->cur_pos) + 1157 acb->cur_qiov.size; 1158 1159 if (ret) { 1160 qed_aio_complete(acb, ret); 1161 return; 1162 } 1163 1164 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1165 qed_copy_from_backing_file(s, start, len, offset, 1166 qed_aio_write_main, acb); 1167 } 1168 1169 /** 1170 * Populate front untouched region of new data cluster 1171 */ 1172 static void qed_aio_write_prefill(void *opaque, int ret) 1173 { 1174 QEDAIOCB *acb = opaque; 1175 BDRVQEDState *s = acb_to_s(acb); 1176 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1177 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1178 1179 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1180 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1181 qed_aio_write_postfill, acb); 1182 } 1183 1184 /** 1185 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1186 */ 1187 static bool qed_should_set_need_check(BDRVQEDState *s) 1188 { 1189 /* The flush before L2 update path ensures consistency */ 1190 if (s->bs->backing) { 1191 return false; 1192 } 1193 1194 return !(s->header.features & QED_F_NEED_CHECK); 1195 } 1196 1197 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1198 { 1199 QEDAIOCB *acb = opaque; 1200 1201 if (ret) { 1202 qed_aio_complete(acb, ret); 1203 return; 1204 } 1205 1206 qed_aio_write_l2_update(acb, 0, 1); 1207 } 1208 1209 /** 1210 * Write new data cluster 1211 * 1212 * @acb: Write request 1213 * @len: Length in bytes 1214 * 1215 * This path is taken when writing to previously unallocated clusters. 1216 */ 1217 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1218 { 1219 BDRVQEDState *s = acb_to_s(acb); 1220 BlockCompletionFunc *cb; 1221 1222 /* Cancel timer when the first allocating request comes in */ 1223 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1224 qed_cancel_need_check_timer(s); 1225 } 1226 1227 /* Freeze this request if another allocating write is in progress */ 1228 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1229 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1230 } 1231 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1232 s->allocating_write_reqs_plugged) { 1233 return; /* wait for existing request to finish */ 1234 } 1235 1236 acb->cur_nclusters = qed_bytes_to_clusters(s, 1237 qed_offset_into_cluster(s, acb->cur_pos) + len); 1238 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1239 1240 if (acb->flags & QED_AIOCB_ZERO) { 1241 /* Skip ahead if the clusters are already zero */ 1242 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1243 qed_aio_start_io(acb); 1244 return; 1245 } 1246 1247 cb = qed_aio_write_zero_cluster; 1248 } else { 1249 cb = qed_aio_write_prefill; 1250 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1251 } 1252 1253 if (qed_should_set_need_check(s)) { 1254 s->header.features |= QED_F_NEED_CHECK; 1255 qed_write_header(s, cb, acb); 1256 } else { 1257 cb(acb, 0); 1258 } 1259 } 1260 1261 /** 1262 * Write data cluster in place 1263 * 1264 * @acb: Write request 1265 * @offset: Cluster offset in bytes 1266 * @len: Length in bytes 1267 * 1268 * This path is taken when writing to already allocated clusters. 1269 */ 1270 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1271 { 1272 /* Allocate buffer for zero writes */ 1273 if (acb->flags & QED_AIOCB_ZERO) { 1274 struct iovec *iov = acb->qiov->iov; 1275 1276 if (!iov->iov_base) { 1277 iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len); 1278 if (iov->iov_base == NULL) { 1279 qed_aio_complete(acb, -ENOMEM); 1280 return; 1281 } 1282 memset(iov->iov_base, 0, iov->iov_len); 1283 } 1284 } 1285 1286 /* Calculate the I/O vector */ 1287 acb->cur_cluster = offset; 1288 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1289 1290 /* Do the actual write */ 1291 qed_aio_write_main(acb, 0); 1292 } 1293 1294 /** 1295 * Write data cluster 1296 * 1297 * @opaque: Write request 1298 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1299 * or -errno 1300 * @offset: Cluster offset in bytes 1301 * @len: Length in bytes 1302 * 1303 * Callback from qed_find_cluster(). 1304 */ 1305 static void qed_aio_write_data(void *opaque, int ret, 1306 uint64_t offset, size_t len) 1307 { 1308 QEDAIOCB *acb = opaque; 1309 1310 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1311 1312 acb->find_cluster_ret = ret; 1313 1314 switch (ret) { 1315 case QED_CLUSTER_FOUND: 1316 qed_aio_write_inplace(acb, offset, len); 1317 break; 1318 1319 case QED_CLUSTER_L2: 1320 case QED_CLUSTER_L1: 1321 case QED_CLUSTER_ZERO: 1322 qed_aio_write_alloc(acb, len); 1323 break; 1324 1325 default: 1326 qed_aio_complete(acb, ret); 1327 break; 1328 } 1329 } 1330 1331 /** 1332 * Read data cluster 1333 * 1334 * @opaque: Read request 1335 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1336 * or -errno 1337 * @offset: Cluster offset in bytes 1338 * @len: Length in bytes 1339 * 1340 * Callback from qed_find_cluster(). 1341 */ 1342 static void qed_aio_read_data(void *opaque, int ret, 1343 uint64_t offset, size_t len) 1344 { 1345 QEDAIOCB *acb = opaque; 1346 BDRVQEDState *s = acb_to_s(acb); 1347 BlockDriverState *bs = acb->common.bs; 1348 1349 /* Adjust offset into cluster */ 1350 offset += qed_offset_into_cluster(s, acb->cur_pos); 1351 1352 trace_qed_aio_read_data(s, acb, ret, offset, len); 1353 1354 if (ret < 0) { 1355 goto err; 1356 } 1357 1358 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1359 1360 /* Handle zero cluster and backing file reads */ 1361 if (ret == QED_CLUSTER_ZERO) { 1362 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1363 qed_aio_start_io(acb); 1364 return; 1365 } else if (ret != QED_CLUSTER_FOUND) { 1366 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1367 &acb->backing_qiov, qed_aio_next_io_cb, acb); 1368 return; 1369 } 1370 1371 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1372 bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE, 1373 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1374 qed_aio_next_io_cb, acb); 1375 return; 1376 1377 err: 1378 qed_aio_complete(acb, ret); 1379 } 1380 1381 /** 1382 * Begin next I/O or complete the request 1383 */ 1384 static void qed_aio_next_io(QEDAIOCB *acb, int ret) 1385 { 1386 BDRVQEDState *s = acb_to_s(acb); 1387 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1388 qed_aio_write_data : qed_aio_read_data; 1389 1390 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1391 1392 if (acb->backing_qiov) { 1393 qemu_iovec_destroy(acb->backing_qiov); 1394 g_free(acb->backing_qiov); 1395 acb->backing_qiov = NULL; 1396 } 1397 1398 /* Handle I/O error */ 1399 if (ret) { 1400 qed_aio_complete(acb, ret); 1401 return; 1402 } 1403 1404 acb->qiov_offset += acb->cur_qiov.size; 1405 acb->cur_pos += acb->cur_qiov.size; 1406 qemu_iovec_reset(&acb->cur_qiov); 1407 1408 /* Complete request */ 1409 if (acb->cur_pos >= acb->end_pos) { 1410 qed_aio_complete(acb, 0); 1411 return; 1412 } 1413 1414 /* Find next cluster and start I/O */ 1415 qed_find_cluster(s, &acb->request, 1416 acb->cur_pos, acb->end_pos - acb->cur_pos, 1417 io_fn, acb); 1418 } 1419 1420 static BlockAIOCB *qed_aio_setup(BlockDriverState *bs, 1421 int64_t sector_num, 1422 QEMUIOVector *qiov, int nb_sectors, 1423 BlockCompletionFunc *cb, 1424 void *opaque, int flags) 1425 { 1426 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1427 1428 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1429 opaque, flags); 1430 1431 acb->flags = flags; 1432 acb->qiov = qiov; 1433 acb->qiov_offset = 0; 1434 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1435 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1436 acb->backing_qiov = NULL; 1437 acb->request.l2_table = NULL; 1438 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1439 1440 /* Start request */ 1441 qed_aio_start_io(acb); 1442 return &acb->common; 1443 } 1444 1445 static BlockAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1446 int64_t sector_num, 1447 QEMUIOVector *qiov, int nb_sectors, 1448 BlockCompletionFunc *cb, 1449 void *opaque) 1450 { 1451 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1452 } 1453 1454 static BlockAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1455 int64_t sector_num, 1456 QEMUIOVector *qiov, int nb_sectors, 1457 BlockCompletionFunc *cb, 1458 void *opaque) 1459 { 1460 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1461 opaque, QED_AIOCB_WRITE); 1462 } 1463 1464 typedef struct { 1465 Coroutine *co; 1466 int ret; 1467 bool done; 1468 } QEDWriteZeroesCB; 1469 1470 static void coroutine_fn qed_co_pwrite_zeroes_cb(void *opaque, int ret) 1471 { 1472 QEDWriteZeroesCB *cb = opaque; 1473 1474 cb->done = true; 1475 cb->ret = ret; 1476 if (cb->co) { 1477 aio_co_wake(cb->co); 1478 } 1479 } 1480 1481 static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs, 1482 int64_t offset, 1483 int count, 1484 BdrvRequestFlags flags) 1485 { 1486 BlockAIOCB *blockacb; 1487 BDRVQEDState *s = bs->opaque; 1488 QEDWriteZeroesCB cb = { .done = false }; 1489 QEMUIOVector qiov; 1490 struct iovec iov; 1491 1492 /* Fall back if the request is not aligned */ 1493 if (qed_offset_into_cluster(s, offset) || 1494 qed_offset_into_cluster(s, count)) { 1495 return -ENOTSUP; 1496 } 1497 1498 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1499 * then it will be allocated during request processing. 1500 */ 1501 iov.iov_base = NULL; 1502 iov.iov_len = count; 1503 1504 qemu_iovec_init_external(&qiov, &iov, 1); 1505 blockacb = qed_aio_setup(bs, offset >> BDRV_SECTOR_BITS, &qiov, 1506 count >> BDRV_SECTOR_BITS, 1507 qed_co_pwrite_zeroes_cb, &cb, 1508 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1509 if (!blockacb) { 1510 return -EIO; 1511 } 1512 if (!cb.done) { 1513 cb.co = qemu_coroutine_self(); 1514 qemu_coroutine_yield(); 1515 } 1516 assert(cb.done); 1517 return cb.ret; 1518 } 1519 1520 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1521 { 1522 BDRVQEDState *s = bs->opaque; 1523 uint64_t old_image_size; 1524 int ret; 1525 1526 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1527 s->header.table_size)) { 1528 return -EINVAL; 1529 } 1530 1531 /* Shrinking is currently not supported */ 1532 if ((uint64_t)offset < s->header.image_size) { 1533 return -ENOTSUP; 1534 } 1535 1536 old_image_size = s->header.image_size; 1537 s->header.image_size = offset; 1538 ret = qed_write_header_sync(s); 1539 if (ret < 0) { 1540 s->header.image_size = old_image_size; 1541 } 1542 return ret; 1543 } 1544 1545 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1546 { 1547 BDRVQEDState *s = bs->opaque; 1548 return s->header.image_size; 1549 } 1550 1551 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1552 { 1553 BDRVQEDState *s = bs->opaque; 1554 1555 memset(bdi, 0, sizeof(*bdi)); 1556 bdi->cluster_size = s->header.cluster_size; 1557 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1558 bdi->unallocated_blocks_are_zero = true; 1559 bdi->can_write_zeroes_with_unmap = true; 1560 return 0; 1561 } 1562 1563 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1564 const char *backing_file, 1565 const char *backing_fmt) 1566 { 1567 BDRVQEDState *s = bs->opaque; 1568 QEDHeader new_header, le_header; 1569 void *buffer; 1570 size_t buffer_len, backing_file_len; 1571 int ret; 1572 1573 /* Refuse to set backing filename if unknown compat feature bits are 1574 * active. If the image uses an unknown compat feature then we may not 1575 * know the layout of data following the header structure and cannot safely 1576 * add a new string. 1577 */ 1578 if (backing_file && (s->header.compat_features & 1579 ~QED_COMPAT_FEATURE_MASK)) { 1580 return -ENOTSUP; 1581 } 1582 1583 memcpy(&new_header, &s->header, sizeof(new_header)); 1584 1585 new_header.features &= ~(QED_F_BACKING_FILE | 1586 QED_F_BACKING_FORMAT_NO_PROBE); 1587 1588 /* Adjust feature flags */ 1589 if (backing_file) { 1590 new_header.features |= QED_F_BACKING_FILE; 1591 1592 if (qed_fmt_is_raw(backing_fmt)) { 1593 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1594 } 1595 } 1596 1597 /* Calculate new header size */ 1598 backing_file_len = 0; 1599 1600 if (backing_file) { 1601 backing_file_len = strlen(backing_file); 1602 } 1603 1604 buffer_len = sizeof(new_header); 1605 new_header.backing_filename_offset = buffer_len; 1606 new_header.backing_filename_size = backing_file_len; 1607 buffer_len += backing_file_len; 1608 1609 /* Make sure we can rewrite header without failing */ 1610 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1611 return -ENOSPC; 1612 } 1613 1614 /* Prepare new header */ 1615 buffer = g_malloc(buffer_len); 1616 1617 qed_header_cpu_to_le(&new_header, &le_header); 1618 memcpy(buffer, &le_header, sizeof(le_header)); 1619 buffer_len = sizeof(le_header); 1620 1621 if (backing_file) { 1622 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1623 buffer_len += backing_file_len; 1624 } 1625 1626 /* Write new header */ 1627 ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len); 1628 g_free(buffer); 1629 if (ret == 0) { 1630 memcpy(&s->header, &new_header, sizeof(new_header)); 1631 } 1632 return ret; 1633 } 1634 1635 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1636 { 1637 BDRVQEDState *s = bs->opaque; 1638 Error *local_err = NULL; 1639 int ret; 1640 1641 bdrv_qed_close(bs); 1642 1643 memset(s, 0, sizeof(BDRVQEDState)); 1644 ret = bdrv_qed_do_open(bs, NULL, bs->open_flags, &local_err); 1645 if (local_err) { 1646 error_propagate(errp, local_err); 1647 error_prepend(errp, "Could not reopen qed layer: "); 1648 return; 1649 } else if (ret < 0) { 1650 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1651 return; 1652 } 1653 } 1654 1655 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1656 BdrvCheckMode fix) 1657 { 1658 BDRVQEDState *s = bs->opaque; 1659 1660 return qed_check(s, result, !!fix); 1661 } 1662 1663 static QemuOptsList qed_create_opts = { 1664 .name = "qed-create-opts", 1665 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1666 .desc = { 1667 { 1668 .name = BLOCK_OPT_SIZE, 1669 .type = QEMU_OPT_SIZE, 1670 .help = "Virtual disk size" 1671 }, 1672 { 1673 .name = BLOCK_OPT_BACKING_FILE, 1674 .type = QEMU_OPT_STRING, 1675 .help = "File name of a base image" 1676 }, 1677 { 1678 .name = BLOCK_OPT_BACKING_FMT, 1679 .type = QEMU_OPT_STRING, 1680 .help = "Image format of the base image" 1681 }, 1682 { 1683 .name = BLOCK_OPT_CLUSTER_SIZE, 1684 .type = QEMU_OPT_SIZE, 1685 .help = "Cluster size (in bytes)", 1686 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1687 }, 1688 { 1689 .name = BLOCK_OPT_TABLE_SIZE, 1690 .type = QEMU_OPT_SIZE, 1691 .help = "L1/L2 table size (in clusters)" 1692 }, 1693 { /* end of list */ } 1694 } 1695 }; 1696 1697 static BlockDriver bdrv_qed = { 1698 .format_name = "qed", 1699 .instance_size = sizeof(BDRVQEDState), 1700 .create_opts = &qed_create_opts, 1701 .supports_backing = true, 1702 1703 .bdrv_probe = bdrv_qed_probe, 1704 .bdrv_open = bdrv_qed_open, 1705 .bdrv_close = bdrv_qed_close, 1706 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1707 .bdrv_create = bdrv_qed_create, 1708 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1709 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1710 .bdrv_aio_readv = bdrv_qed_aio_readv, 1711 .bdrv_aio_writev = bdrv_qed_aio_writev, 1712 .bdrv_co_pwrite_zeroes = bdrv_qed_co_pwrite_zeroes, 1713 .bdrv_truncate = bdrv_qed_truncate, 1714 .bdrv_getlength = bdrv_qed_getlength, 1715 .bdrv_get_info = bdrv_qed_get_info, 1716 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1717 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1718 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1719 .bdrv_check = bdrv_qed_check, 1720 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1721 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1722 .bdrv_drain = bdrv_qed_drain, 1723 }; 1724 1725 static void bdrv_qed_init(void) 1726 { 1727 bdrv_register(&bdrv_qed); 1728 } 1729 1730 block_init(bdrv_qed_init); 1731