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