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 void bdrv_qed_drain(BlockDriverState *bs) 381 { 382 BDRVQEDState *s = bs->opaque; 383 384 /* Cancel timer and start doing I/O that were meant to happen as if it 385 * fired, that way we get bdrv_drain() taking care of the ongoing requests 386 * correctly. */ 387 qed_cancel_need_check_timer(s); 388 qed_plug_allocating_write_reqs(s); 389 bdrv_aio_flush(s->bs, qed_clear_need_check, s); 390 } 391 392 static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, 393 Error **errp) 394 { 395 BDRVQEDState *s = bs->opaque; 396 QEDHeader le_header; 397 int64_t file_size; 398 int ret; 399 400 s->bs = bs; 401 QSIMPLEQ_INIT(&s->allocating_write_reqs); 402 403 ret = bdrv_pread(bs->file->bs, 0, &le_header, sizeof(le_header)); 404 if (ret < 0) { 405 return ret; 406 } 407 qed_header_le_to_cpu(&le_header, &s->header); 408 409 if (s->header.magic != QED_MAGIC) { 410 error_setg(errp, "Image not in QED format"); 411 return -EINVAL; 412 } 413 if (s->header.features & ~QED_FEATURE_MASK) { 414 /* image uses unsupported feature bits */ 415 char buf[64]; 416 snprintf(buf, sizeof(buf), "%" PRIx64, 417 s->header.features & ~QED_FEATURE_MASK); 418 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 419 bdrv_get_device_or_node_name(bs), "QED", buf); 420 return -ENOTSUP; 421 } 422 if (!qed_is_cluster_size_valid(s->header.cluster_size)) { 423 return -EINVAL; 424 } 425 426 /* Round down file size to the last cluster */ 427 file_size = bdrv_getlength(bs->file->bs); 428 if (file_size < 0) { 429 return file_size; 430 } 431 s->file_size = qed_start_of_cluster(s, file_size); 432 433 if (!qed_is_table_size_valid(s->header.table_size)) { 434 return -EINVAL; 435 } 436 if (!qed_is_image_size_valid(s->header.image_size, 437 s->header.cluster_size, 438 s->header.table_size)) { 439 return -EINVAL; 440 } 441 if (!qed_check_table_offset(s, s->header.l1_table_offset)) { 442 return -EINVAL; 443 } 444 445 s->table_nelems = (s->header.cluster_size * s->header.table_size) / 446 sizeof(uint64_t); 447 s->l2_shift = ctz32(s->header.cluster_size); 448 s->l2_mask = s->table_nelems - 1; 449 s->l1_shift = s->l2_shift + ctz32(s->table_nelems); 450 451 /* Header size calculation must not overflow uint32_t */ 452 if (s->header.header_size > UINT32_MAX / s->header.cluster_size) { 453 return -EINVAL; 454 } 455 456 if ((s->header.features & QED_F_BACKING_FILE)) { 457 if ((uint64_t)s->header.backing_filename_offset + 458 s->header.backing_filename_size > 459 s->header.cluster_size * s->header.header_size) { 460 return -EINVAL; 461 } 462 463 ret = qed_read_string(bs->file->bs, s->header.backing_filename_offset, 464 s->header.backing_filename_size, bs->backing_file, 465 sizeof(bs->backing_file)); 466 if (ret < 0) { 467 return ret; 468 } 469 470 if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) { 471 pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw"); 472 } 473 } 474 475 /* Reset unknown autoclear feature bits. This is a backwards 476 * compatibility mechanism that allows images to be opened by older 477 * programs, which "knock out" unknown feature bits. When an image is 478 * opened by a newer program again it can detect that the autoclear 479 * feature is no longer valid. 480 */ 481 if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 && 482 !bdrv_is_read_only(bs->file->bs) && !(flags & BDRV_O_INACTIVE)) { 483 s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK; 484 485 ret = qed_write_header_sync(s); 486 if (ret) { 487 return ret; 488 } 489 490 /* From here on only known autoclear feature bits are valid */ 491 bdrv_flush(bs->file->bs); 492 } 493 494 s->l1_table = qed_alloc_table(s); 495 qed_init_l2_cache(&s->l2_cache); 496 497 ret = qed_read_l1_table_sync(s); 498 if (ret) { 499 goto out; 500 } 501 502 /* If image was not closed cleanly, check consistency */ 503 if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) { 504 /* Read-only images cannot be fixed. There is no risk of corruption 505 * since write operations are not possible. Therefore, allow 506 * potentially inconsistent images to be opened read-only. This can 507 * aid data recovery from an otherwise inconsistent image. 508 */ 509 if (!bdrv_is_read_only(bs->file->bs) && 510 !(flags & BDRV_O_INACTIVE)) { 511 BdrvCheckResult result = {0}; 512 513 ret = qed_check(s, &result, true); 514 if (ret) { 515 goto out; 516 } 517 } 518 } 519 520 bdrv_qed_attach_aio_context(bs, bdrv_get_aio_context(bs)); 521 522 out: 523 if (ret) { 524 qed_free_l2_cache(&s->l2_cache); 525 qemu_vfree(s->l1_table); 526 } 527 return ret; 528 } 529 530 static void bdrv_qed_refresh_limits(BlockDriverState *bs, Error **errp) 531 { 532 BDRVQEDState *s = bs->opaque; 533 534 bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS; 535 } 536 537 /* We have nothing to do for QED reopen, stubs just return 538 * success */ 539 static int bdrv_qed_reopen_prepare(BDRVReopenState *state, 540 BlockReopenQueue *queue, Error **errp) 541 { 542 return 0; 543 } 544 545 static void bdrv_qed_close(BlockDriverState *bs) 546 { 547 BDRVQEDState *s = bs->opaque; 548 549 bdrv_qed_detach_aio_context(bs); 550 551 /* Ensure writes reach stable storage */ 552 bdrv_flush(bs->file->bs); 553 554 /* Clean shutdown, no check required on next open */ 555 if (s->header.features & QED_F_NEED_CHECK) { 556 s->header.features &= ~QED_F_NEED_CHECK; 557 qed_write_header_sync(s); 558 } 559 560 qed_free_l2_cache(&s->l2_cache); 561 qemu_vfree(s->l1_table); 562 } 563 564 static int qed_create(const char *filename, uint32_t cluster_size, 565 uint64_t image_size, uint32_t table_size, 566 const char *backing_file, const char *backing_fmt, 567 QemuOpts *opts, Error **errp) 568 { 569 QEDHeader header = { 570 .magic = QED_MAGIC, 571 .cluster_size = cluster_size, 572 .table_size = table_size, 573 .header_size = 1, 574 .features = 0, 575 .compat_features = 0, 576 .l1_table_offset = cluster_size, 577 .image_size = image_size, 578 }; 579 QEDHeader le_header; 580 uint8_t *l1_table = NULL; 581 size_t l1_size = header.cluster_size * header.table_size; 582 Error *local_err = NULL; 583 int ret = 0; 584 BlockBackend *blk; 585 586 ret = bdrv_create_file(filename, opts, &local_err); 587 if (ret < 0) { 588 error_propagate(errp, local_err); 589 return ret; 590 } 591 592 blk = blk_new_open("image", filename, NULL, NULL, 593 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, 594 &local_err); 595 if (blk == NULL) { 596 error_propagate(errp, local_err); 597 return -EIO; 598 } 599 600 blk_set_allow_write_beyond_eof(blk, true); 601 602 /* File must start empty and grow, check truncate is supported */ 603 ret = blk_truncate(blk, 0); 604 if (ret < 0) { 605 goto out; 606 } 607 608 if (backing_file) { 609 header.features |= QED_F_BACKING_FILE; 610 header.backing_filename_offset = sizeof(le_header); 611 header.backing_filename_size = strlen(backing_file); 612 613 if (qed_fmt_is_raw(backing_fmt)) { 614 header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 615 } 616 } 617 618 qed_header_cpu_to_le(&header, &le_header); 619 ret = blk_pwrite(blk, 0, &le_header, sizeof(le_header)); 620 if (ret < 0) { 621 goto out; 622 } 623 ret = blk_pwrite(blk, sizeof(le_header), backing_file, 624 header.backing_filename_size); 625 if (ret < 0) { 626 goto out; 627 } 628 629 l1_table = g_malloc0(l1_size); 630 ret = blk_pwrite(blk, header.l1_table_offset, l1_table, l1_size); 631 if (ret < 0) { 632 goto out; 633 } 634 635 ret = 0; /* success */ 636 out: 637 g_free(l1_table); 638 blk_unref(blk); 639 return ret; 640 } 641 642 static int bdrv_qed_create(const char *filename, QemuOpts *opts, Error **errp) 643 { 644 uint64_t image_size = 0; 645 uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE; 646 uint32_t table_size = QED_DEFAULT_TABLE_SIZE; 647 char *backing_file = NULL; 648 char *backing_fmt = NULL; 649 int ret; 650 651 image_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 652 BDRV_SECTOR_SIZE); 653 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 654 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 655 cluster_size = qemu_opt_get_size_del(opts, 656 BLOCK_OPT_CLUSTER_SIZE, 657 QED_DEFAULT_CLUSTER_SIZE); 658 table_size = qemu_opt_get_size_del(opts, BLOCK_OPT_TABLE_SIZE, 659 QED_DEFAULT_TABLE_SIZE); 660 661 if (!qed_is_cluster_size_valid(cluster_size)) { 662 error_setg(errp, "QED cluster size must be within range [%u, %u] " 663 "and power of 2", 664 QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE); 665 ret = -EINVAL; 666 goto finish; 667 } 668 if (!qed_is_table_size_valid(table_size)) { 669 error_setg(errp, "QED table size must be within range [%u, %u] " 670 "and power of 2", 671 QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE); 672 ret = -EINVAL; 673 goto finish; 674 } 675 if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) { 676 error_setg(errp, "QED image size must be a non-zero multiple of " 677 "cluster size and less than %" PRIu64 " bytes", 678 qed_max_image_size(cluster_size, table_size)); 679 ret = -EINVAL; 680 goto finish; 681 } 682 683 ret = qed_create(filename, cluster_size, image_size, table_size, 684 backing_file, backing_fmt, opts, errp); 685 686 finish: 687 g_free(backing_file); 688 g_free(backing_fmt); 689 return ret; 690 } 691 692 typedef struct { 693 BlockDriverState *bs; 694 Coroutine *co; 695 uint64_t pos; 696 int64_t status; 697 int *pnum; 698 BlockDriverState **file; 699 } QEDIsAllocatedCB; 700 701 static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len) 702 { 703 QEDIsAllocatedCB *cb = opaque; 704 BDRVQEDState *s = cb->bs->opaque; 705 *cb->pnum = len / BDRV_SECTOR_SIZE; 706 switch (ret) { 707 case QED_CLUSTER_FOUND: 708 offset |= qed_offset_into_cluster(s, cb->pos); 709 cb->status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | offset; 710 *cb->file = cb->bs->file->bs; 711 break; 712 case QED_CLUSTER_ZERO: 713 cb->status = BDRV_BLOCK_ZERO; 714 break; 715 case QED_CLUSTER_L2: 716 case QED_CLUSTER_L1: 717 cb->status = 0; 718 break; 719 default: 720 assert(ret < 0); 721 cb->status = ret; 722 break; 723 } 724 725 if (cb->co) { 726 qemu_coroutine_enter(cb->co, NULL); 727 } 728 } 729 730 static int64_t coroutine_fn bdrv_qed_co_get_block_status(BlockDriverState *bs, 731 int64_t sector_num, 732 int nb_sectors, int *pnum, 733 BlockDriverState **file) 734 { 735 BDRVQEDState *s = bs->opaque; 736 size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE; 737 QEDIsAllocatedCB cb = { 738 .bs = bs, 739 .pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE, 740 .status = BDRV_BLOCK_OFFSET_MASK, 741 .pnum = pnum, 742 .file = file, 743 }; 744 QEDRequest request = { .l2_table = NULL }; 745 746 qed_find_cluster(s, &request, cb.pos, len, qed_is_allocated_cb, &cb); 747 748 /* Now sleep if the callback wasn't invoked immediately */ 749 while (cb.status == BDRV_BLOCK_OFFSET_MASK) { 750 cb.co = qemu_coroutine_self(); 751 qemu_coroutine_yield(); 752 } 753 754 qed_unref_l2_cache_entry(request.l2_table); 755 756 return cb.status; 757 } 758 759 static BDRVQEDState *acb_to_s(QEDAIOCB *acb) 760 { 761 return acb->common.bs->opaque; 762 } 763 764 /** 765 * Read from the backing file or zero-fill if no backing file 766 * 767 * @s: QED state 768 * @pos: Byte position in device 769 * @qiov: Destination I/O vector 770 * @backing_qiov: Possibly shortened copy of qiov, to be allocated here 771 * @cb: Completion function 772 * @opaque: User data for completion function 773 * 774 * This function reads qiov->size bytes starting at pos from the backing file. 775 * If there is no backing file then zeroes are read. 776 */ 777 static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos, 778 QEMUIOVector *qiov, 779 QEMUIOVector **backing_qiov, 780 BlockCompletionFunc *cb, void *opaque) 781 { 782 uint64_t backing_length = 0; 783 size_t size; 784 785 /* If there is a backing file, get its length. Treat the absence of a 786 * backing file like a zero length backing file. 787 */ 788 if (s->bs->backing) { 789 int64_t l = bdrv_getlength(s->bs->backing->bs); 790 if (l < 0) { 791 cb(opaque, l); 792 return; 793 } 794 backing_length = l; 795 } 796 797 /* Zero all sectors if reading beyond the end of the backing file */ 798 if (pos >= backing_length || 799 pos + qiov->size > backing_length) { 800 qemu_iovec_memset(qiov, 0, 0, qiov->size); 801 } 802 803 /* Complete now if there are no backing file sectors to read */ 804 if (pos >= backing_length) { 805 cb(opaque, 0); 806 return; 807 } 808 809 /* If the read straddles the end of the backing file, shorten it */ 810 size = MIN((uint64_t)backing_length - pos, qiov->size); 811 812 assert(*backing_qiov == NULL); 813 *backing_qiov = g_new(QEMUIOVector, 1); 814 qemu_iovec_init(*backing_qiov, qiov->niov); 815 qemu_iovec_concat(*backing_qiov, qiov, 0, size); 816 817 BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO); 818 bdrv_aio_readv(s->bs->backing->bs, pos / BDRV_SECTOR_SIZE, 819 *backing_qiov, size / BDRV_SECTOR_SIZE, cb, opaque); 820 } 821 822 typedef struct { 823 GenericCB gencb; 824 BDRVQEDState *s; 825 QEMUIOVector qiov; 826 QEMUIOVector *backing_qiov; 827 struct iovec iov; 828 uint64_t offset; 829 } CopyFromBackingFileCB; 830 831 static void qed_copy_from_backing_file_cb(void *opaque, int ret) 832 { 833 CopyFromBackingFileCB *copy_cb = opaque; 834 qemu_vfree(copy_cb->iov.iov_base); 835 gencb_complete(©_cb->gencb, ret); 836 } 837 838 static void qed_copy_from_backing_file_write(void *opaque, int ret) 839 { 840 CopyFromBackingFileCB *copy_cb = opaque; 841 BDRVQEDState *s = copy_cb->s; 842 843 if (copy_cb->backing_qiov) { 844 qemu_iovec_destroy(copy_cb->backing_qiov); 845 g_free(copy_cb->backing_qiov); 846 copy_cb->backing_qiov = NULL; 847 } 848 849 if (ret) { 850 qed_copy_from_backing_file_cb(copy_cb, ret); 851 return; 852 } 853 854 BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE); 855 bdrv_aio_writev(s->bs->file->bs, copy_cb->offset / BDRV_SECTOR_SIZE, 856 ©_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE, 857 qed_copy_from_backing_file_cb, copy_cb); 858 } 859 860 /** 861 * Copy data from backing file into the image 862 * 863 * @s: QED state 864 * @pos: Byte position in device 865 * @len: Number of bytes 866 * @offset: Byte offset in image file 867 * @cb: Completion function 868 * @opaque: User data for completion function 869 */ 870 static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, 871 uint64_t len, uint64_t offset, 872 BlockCompletionFunc *cb, 873 void *opaque) 874 { 875 CopyFromBackingFileCB *copy_cb; 876 877 /* Skip copy entirely if there is no work to do */ 878 if (len == 0) { 879 cb(opaque, 0); 880 return; 881 } 882 883 copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque); 884 copy_cb->s = s; 885 copy_cb->offset = offset; 886 copy_cb->backing_qiov = NULL; 887 copy_cb->iov.iov_base = qemu_blockalign(s->bs, len); 888 copy_cb->iov.iov_len = len; 889 qemu_iovec_init_external(©_cb->qiov, ©_cb->iov, 1); 890 891 qed_read_backing_file(s, pos, ©_cb->qiov, ©_cb->backing_qiov, 892 qed_copy_from_backing_file_write, copy_cb); 893 } 894 895 /** 896 * Link one or more contiguous clusters into a table 897 * 898 * @s: QED state 899 * @table: L2 table 900 * @index: First cluster index 901 * @n: Number of contiguous clusters 902 * @cluster: First cluster offset 903 * 904 * The cluster offset may be an allocated byte offset in the image file, the 905 * zero cluster marker, or the unallocated cluster marker. 906 */ 907 static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index, 908 unsigned int n, uint64_t cluster) 909 { 910 int i; 911 for (i = index; i < index + n; i++) { 912 table->offsets[i] = cluster; 913 if (!qed_offset_is_unalloc_cluster(cluster) && 914 !qed_offset_is_zero_cluster(cluster)) { 915 cluster += s->header.cluster_size; 916 } 917 } 918 } 919 920 static void qed_aio_complete_bh(void *opaque) 921 { 922 QEDAIOCB *acb = opaque; 923 BlockCompletionFunc *cb = acb->common.cb; 924 void *user_opaque = acb->common.opaque; 925 int ret = acb->bh_ret; 926 927 qemu_bh_delete(acb->bh); 928 qemu_aio_unref(acb); 929 930 /* Invoke callback */ 931 cb(user_opaque, ret); 932 } 933 934 static void qed_aio_complete(QEDAIOCB *acb, int ret) 935 { 936 BDRVQEDState *s = acb_to_s(acb); 937 938 trace_qed_aio_complete(s, acb, ret); 939 940 /* Free resources */ 941 qemu_iovec_destroy(&acb->cur_qiov); 942 qed_unref_l2_cache_entry(acb->request.l2_table); 943 944 /* Free the buffer we may have allocated for zero writes */ 945 if (acb->flags & QED_AIOCB_ZERO) { 946 qemu_vfree(acb->qiov->iov[0].iov_base); 947 acb->qiov->iov[0].iov_base = NULL; 948 } 949 950 /* Arrange for a bh to invoke the completion function */ 951 acb->bh_ret = ret; 952 acb->bh = aio_bh_new(bdrv_get_aio_context(acb->common.bs), 953 qed_aio_complete_bh, acb); 954 qemu_bh_schedule(acb->bh); 955 956 /* Start next allocating write request waiting behind this one. Note that 957 * requests enqueue themselves when they first hit an unallocated cluster 958 * but they wait until the entire request is finished before waking up the 959 * next request in the queue. This ensures that we don't cycle through 960 * requests multiple times but rather finish one at a time completely. 961 */ 962 if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 963 QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next); 964 acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs); 965 if (acb) { 966 qed_aio_next_io(acb, 0); 967 } else if (s->header.features & QED_F_NEED_CHECK) { 968 qed_start_need_check_timer(s); 969 } 970 } 971 } 972 973 /** 974 * Commit the current L2 table to the cache 975 */ 976 static void qed_commit_l2_update(void *opaque, int ret) 977 { 978 QEDAIOCB *acb = opaque; 979 BDRVQEDState *s = acb_to_s(acb); 980 CachedL2Table *l2_table = acb->request.l2_table; 981 uint64_t l2_offset = l2_table->offset; 982 983 qed_commit_l2_cache_entry(&s->l2_cache, l2_table); 984 985 /* This is guaranteed to succeed because we just committed the entry to the 986 * cache. 987 */ 988 acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset); 989 assert(acb->request.l2_table != NULL); 990 991 qed_aio_next_io(opaque, ret); 992 } 993 994 /** 995 * Update L1 table with new L2 table offset and write it out 996 */ 997 static void qed_aio_write_l1_update(void *opaque, int ret) 998 { 999 QEDAIOCB *acb = opaque; 1000 BDRVQEDState *s = acb_to_s(acb); 1001 int index; 1002 1003 if (ret) { 1004 qed_aio_complete(acb, ret); 1005 return; 1006 } 1007 1008 index = qed_l1_index(s, acb->cur_pos); 1009 s->l1_table->offsets[index] = acb->request.l2_table->offset; 1010 1011 qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb); 1012 } 1013 1014 /** 1015 * Update L2 table with new cluster offsets and write them out 1016 */ 1017 static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset) 1018 { 1019 BDRVQEDState *s = acb_to_s(acb); 1020 bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1; 1021 int index; 1022 1023 if (ret) { 1024 goto err; 1025 } 1026 1027 if (need_alloc) { 1028 qed_unref_l2_cache_entry(acb->request.l2_table); 1029 acb->request.l2_table = qed_new_l2_table(s); 1030 } 1031 1032 index = qed_l2_index(s, acb->cur_pos); 1033 qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters, 1034 offset); 1035 1036 if (need_alloc) { 1037 /* Write out the whole new L2 table */ 1038 qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true, 1039 qed_aio_write_l1_update, acb); 1040 } else { 1041 /* Write out only the updated part of the L2 table */ 1042 qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false, 1043 qed_aio_next_io, acb); 1044 } 1045 return; 1046 1047 err: 1048 qed_aio_complete(acb, ret); 1049 } 1050 1051 static void qed_aio_write_l2_update_cb(void *opaque, int ret) 1052 { 1053 QEDAIOCB *acb = opaque; 1054 qed_aio_write_l2_update(acb, ret, acb->cur_cluster); 1055 } 1056 1057 /** 1058 * Flush new data clusters before updating the L2 table 1059 * 1060 * This flush is necessary when a backing file is in use. A crash during an 1061 * allocating write could result in empty clusters in the image. If the write 1062 * only touched a subregion of the cluster, then backing image sectors have 1063 * been lost in the untouched region. The solution is to flush after writing a 1064 * new data cluster and before updating the L2 table. 1065 */ 1066 static void qed_aio_write_flush_before_l2_update(void *opaque, int ret) 1067 { 1068 QEDAIOCB *acb = opaque; 1069 BDRVQEDState *s = acb_to_s(acb); 1070 1071 if (!bdrv_aio_flush(s->bs->file->bs, qed_aio_write_l2_update_cb, opaque)) { 1072 qed_aio_complete(acb, -EIO); 1073 } 1074 } 1075 1076 /** 1077 * Write data to the image file 1078 */ 1079 static void qed_aio_write_main(void *opaque, int ret) 1080 { 1081 QEDAIOCB *acb = opaque; 1082 BDRVQEDState *s = acb_to_s(acb); 1083 uint64_t offset = acb->cur_cluster + 1084 qed_offset_into_cluster(s, acb->cur_pos); 1085 BlockCompletionFunc *next_fn; 1086 1087 trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size); 1088 1089 if (ret) { 1090 qed_aio_complete(acb, ret); 1091 return; 1092 } 1093 1094 if (acb->find_cluster_ret == QED_CLUSTER_FOUND) { 1095 next_fn = qed_aio_next_io; 1096 } else { 1097 if (s->bs->backing) { 1098 next_fn = qed_aio_write_flush_before_l2_update; 1099 } else { 1100 next_fn = qed_aio_write_l2_update_cb; 1101 } 1102 } 1103 1104 BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO); 1105 bdrv_aio_writev(s->bs->file->bs, offset / BDRV_SECTOR_SIZE, 1106 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1107 next_fn, acb); 1108 } 1109 1110 /** 1111 * Populate back untouched region of new data cluster 1112 */ 1113 static void qed_aio_write_postfill(void *opaque, int ret) 1114 { 1115 QEDAIOCB *acb = opaque; 1116 BDRVQEDState *s = acb_to_s(acb); 1117 uint64_t start = acb->cur_pos + acb->cur_qiov.size; 1118 uint64_t len = 1119 qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start; 1120 uint64_t offset = acb->cur_cluster + 1121 qed_offset_into_cluster(s, acb->cur_pos) + 1122 acb->cur_qiov.size; 1123 1124 if (ret) { 1125 qed_aio_complete(acb, ret); 1126 return; 1127 } 1128 1129 trace_qed_aio_write_postfill(s, acb, start, len, offset); 1130 qed_copy_from_backing_file(s, start, len, offset, 1131 qed_aio_write_main, acb); 1132 } 1133 1134 /** 1135 * Populate front untouched region of new data cluster 1136 */ 1137 static void qed_aio_write_prefill(void *opaque, int ret) 1138 { 1139 QEDAIOCB *acb = opaque; 1140 BDRVQEDState *s = acb_to_s(acb); 1141 uint64_t start = qed_start_of_cluster(s, acb->cur_pos); 1142 uint64_t len = qed_offset_into_cluster(s, acb->cur_pos); 1143 1144 trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster); 1145 qed_copy_from_backing_file(s, start, len, acb->cur_cluster, 1146 qed_aio_write_postfill, acb); 1147 } 1148 1149 /** 1150 * Check if the QED_F_NEED_CHECK bit should be set during allocating write 1151 */ 1152 static bool qed_should_set_need_check(BDRVQEDState *s) 1153 { 1154 /* The flush before L2 update path ensures consistency */ 1155 if (s->bs->backing) { 1156 return false; 1157 } 1158 1159 return !(s->header.features & QED_F_NEED_CHECK); 1160 } 1161 1162 static void qed_aio_write_zero_cluster(void *opaque, int ret) 1163 { 1164 QEDAIOCB *acb = opaque; 1165 1166 if (ret) { 1167 qed_aio_complete(acb, ret); 1168 return; 1169 } 1170 1171 qed_aio_write_l2_update(acb, 0, 1); 1172 } 1173 1174 /** 1175 * Write new data cluster 1176 * 1177 * @acb: Write request 1178 * @len: Length in bytes 1179 * 1180 * This path is taken when writing to previously unallocated clusters. 1181 */ 1182 static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len) 1183 { 1184 BDRVQEDState *s = acb_to_s(acb); 1185 BlockCompletionFunc *cb; 1186 1187 /* Cancel timer when the first allocating request comes in */ 1188 if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) { 1189 qed_cancel_need_check_timer(s); 1190 } 1191 1192 /* Freeze this request if another allocating write is in progress */ 1193 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) { 1194 QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next); 1195 } 1196 if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) || 1197 s->allocating_write_reqs_plugged) { 1198 return; /* wait for existing request to finish */ 1199 } 1200 1201 acb->cur_nclusters = qed_bytes_to_clusters(s, 1202 qed_offset_into_cluster(s, acb->cur_pos) + len); 1203 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1204 1205 if (acb->flags & QED_AIOCB_ZERO) { 1206 /* Skip ahead if the clusters are already zero */ 1207 if (acb->find_cluster_ret == QED_CLUSTER_ZERO) { 1208 qed_aio_next_io(acb, 0); 1209 return; 1210 } 1211 1212 cb = qed_aio_write_zero_cluster; 1213 } else { 1214 cb = qed_aio_write_prefill; 1215 acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters); 1216 } 1217 1218 if (qed_should_set_need_check(s)) { 1219 s->header.features |= QED_F_NEED_CHECK; 1220 qed_write_header(s, cb, acb); 1221 } else { 1222 cb(acb, 0); 1223 } 1224 } 1225 1226 /** 1227 * Write data cluster in place 1228 * 1229 * @acb: Write request 1230 * @offset: Cluster offset in bytes 1231 * @len: Length in bytes 1232 * 1233 * This path is taken when writing to already allocated clusters. 1234 */ 1235 static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len) 1236 { 1237 /* Allocate buffer for zero writes */ 1238 if (acb->flags & QED_AIOCB_ZERO) { 1239 struct iovec *iov = acb->qiov->iov; 1240 1241 if (!iov->iov_base) { 1242 iov->iov_base = qemu_try_blockalign(acb->common.bs, iov->iov_len); 1243 if (iov->iov_base == NULL) { 1244 qed_aio_complete(acb, -ENOMEM); 1245 return; 1246 } 1247 memset(iov->iov_base, 0, iov->iov_len); 1248 } 1249 } 1250 1251 /* Calculate the I/O vector */ 1252 acb->cur_cluster = offset; 1253 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1254 1255 /* Do the actual write */ 1256 qed_aio_write_main(acb, 0); 1257 } 1258 1259 /** 1260 * Write data cluster 1261 * 1262 * @opaque: Write request 1263 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1264 * or -errno 1265 * @offset: Cluster offset in bytes 1266 * @len: Length in bytes 1267 * 1268 * Callback from qed_find_cluster(). 1269 */ 1270 static void qed_aio_write_data(void *opaque, int ret, 1271 uint64_t offset, size_t len) 1272 { 1273 QEDAIOCB *acb = opaque; 1274 1275 trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len); 1276 1277 acb->find_cluster_ret = ret; 1278 1279 switch (ret) { 1280 case QED_CLUSTER_FOUND: 1281 qed_aio_write_inplace(acb, offset, len); 1282 break; 1283 1284 case QED_CLUSTER_L2: 1285 case QED_CLUSTER_L1: 1286 case QED_CLUSTER_ZERO: 1287 qed_aio_write_alloc(acb, len); 1288 break; 1289 1290 default: 1291 qed_aio_complete(acb, ret); 1292 break; 1293 } 1294 } 1295 1296 /** 1297 * Read data cluster 1298 * 1299 * @opaque: Read request 1300 * @ret: QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1, 1301 * or -errno 1302 * @offset: Cluster offset in bytes 1303 * @len: Length in bytes 1304 * 1305 * Callback from qed_find_cluster(). 1306 */ 1307 static void qed_aio_read_data(void *opaque, int ret, 1308 uint64_t offset, size_t len) 1309 { 1310 QEDAIOCB *acb = opaque; 1311 BDRVQEDState *s = acb_to_s(acb); 1312 BlockDriverState *bs = acb->common.bs; 1313 1314 /* Adjust offset into cluster */ 1315 offset += qed_offset_into_cluster(s, acb->cur_pos); 1316 1317 trace_qed_aio_read_data(s, acb, ret, offset, len); 1318 1319 if (ret < 0) { 1320 goto err; 1321 } 1322 1323 qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len); 1324 1325 /* Handle zero cluster and backing file reads */ 1326 if (ret == QED_CLUSTER_ZERO) { 1327 qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size); 1328 qed_aio_next_io(acb, 0); 1329 return; 1330 } else if (ret != QED_CLUSTER_FOUND) { 1331 qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov, 1332 &acb->backing_qiov, qed_aio_next_io, acb); 1333 return; 1334 } 1335 1336 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1337 bdrv_aio_readv(bs->file->bs, offset / BDRV_SECTOR_SIZE, 1338 &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE, 1339 qed_aio_next_io, acb); 1340 return; 1341 1342 err: 1343 qed_aio_complete(acb, ret); 1344 } 1345 1346 /** 1347 * Begin next I/O or complete the request 1348 */ 1349 static void qed_aio_next_io(void *opaque, int ret) 1350 { 1351 QEDAIOCB *acb = opaque; 1352 BDRVQEDState *s = acb_to_s(acb); 1353 QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ? 1354 qed_aio_write_data : qed_aio_read_data; 1355 1356 trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size); 1357 1358 if (acb->backing_qiov) { 1359 qemu_iovec_destroy(acb->backing_qiov); 1360 g_free(acb->backing_qiov); 1361 acb->backing_qiov = NULL; 1362 } 1363 1364 /* Handle I/O error */ 1365 if (ret) { 1366 qed_aio_complete(acb, ret); 1367 return; 1368 } 1369 1370 acb->qiov_offset += acb->cur_qiov.size; 1371 acb->cur_pos += acb->cur_qiov.size; 1372 qemu_iovec_reset(&acb->cur_qiov); 1373 1374 /* Complete request */ 1375 if (acb->cur_pos >= acb->end_pos) { 1376 qed_aio_complete(acb, 0); 1377 return; 1378 } 1379 1380 /* Find next cluster and start I/O */ 1381 qed_find_cluster(s, &acb->request, 1382 acb->cur_pos, acb->end_pos - acb->cur_pos, 1383 io_fn, acb); 1384 } 1385 1386 static BlockAIOCB *qed_aio_setup(BlockDriverState *bs, 1387 int64_t sector_num, 1388 QEMUIOVector *qiov, int nb_sectors, 1389 BlockCompletionFunc *cb, 1390 void *opaque, int flags) 1391 { 1392 QEDAIOCB *acb = qemu_aio_get(&qed_aiocb_info, bs, cb, opaque); 1393 1394 trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors, 1395 opaque, flags); 1396 1397 acb->flags = flags; 1398 acb->qiov = qiov; 1399 acb->qiov_offset = 0; 1400 acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE; 1401 acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE; 1402 acb->backing_qiov = NULL; 1403 acb->request.l2_table = NULL; 1404 qemu_iovec_init(&acb->cur_qiov, qiov->niov); 1405 1406 /* Start request */ 1407 qed_aio_next_io(acb, 0); 1408 return &acb->common; 1409 } 1410 1411 static BlockAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs, 1412 int64_t sector_num, 1413 QEMUIOVector *qiov, int nb_sectors, 1414 BlockCompletionFunc *cb, 1415 void *opaque) 1416 { 1417 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 1418 } 1419 1420 static BlockAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs, 1421 int64_t sector_num, 1422 QEMUIOVector *qiov, int nb_sectors, 1423 BlockCompletionFunc *cb, 1424 void *opaque) 1425 { 1426 return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, 1427 opaque, QED_AIOCB_WRITE); 1428 } 1429 1430 typedef struct { 1431 Coroutine *co; 1432 int ret; 1433 bool done; 1434 } QEDWriteZeroesCB; 1435 1436 static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret) 1437 { 1438 QEDWriteZeroesCB *cb = opaque; 1439 1440 cb->done = true; 1441 cb->ret = ret; 1442 if (cb->co) { 1443 qemu_coroutine_enter(cb->co, NULL); 1444 } 1445 } 1446 1447 static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs, 1448 int64_t sector_num, 1449 int nb_sectors, 1450 BdrvRequestFlags flags) 1451 { 1452 BlockAIOCB *blockacb; 1453 BDRVQEDState *s = bs->opaque; 1454 QEDWriteZeroesCB cb = { .done = false }; 1455 QEMUIOVector qiov; 1456 struct iovec iov; 1457 1458 /* Refuse if there are untouched backing file sectors */ 1459 if (bs->backing) { 1460 if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) { 1461 return -ENOTSUP; 1462 } 1463 if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) { 1464 return -ENOTSUP; 1465 } 1466 } 1467 1468 /* Zero writes start without an I/O buffer. If a buffer becomes necessary 1469 * then it will be allocated during request processing. 1470 */ 1471 iov.iov_base = NULL, 1472 iov.iov_len = nb_sectors * BDRV_SECTOR_SIZE, 1473 1474 qemu_iovec_init_external(&qiov, &iov, 1); 1475 blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors, 1476 qed_co_write_zeroes_cb, &cb, 1477 QED_AIOCB_WRITE | QED_AIOCB_ZERO); 1478 if (!blockacb) { 1479 return -EIO; 1480 } 1481 if (!cb.done) { 1482 cb.co = qemu_coroutine_self(); 1483 qemu_coroutine_yield(); 1484 } 1485 assert(cb.done); 1486 return cb.ret; 1487 } 1488 1489 static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset) 1490 { 1491 BDRVQEDState *s = bs->opaque; 1492 uint64_t old_image_size; 1493 int ret; 1494 1495 if (!qed_is_image_size_valid(offset, s->header.cluster_size, 1496 s->header.table_size)) { 1497 return -EINVAL; 1498 } 1499 1500 /* Shrinking is currently not supported */ 1501 if ((uint64_t)offset < s->header.image_size) { 1502 return -ENOTSUP; 1503 } 1504 1505 old_image_size = s->header.image_size; 1506 s->header.image_size = offset; 1507 ret = qed_write_header_sync(s); 1508 if (ret < 0) { 1509 s->header.image_size = old_image_size; 1510 } 1511 return ret; 1512 } 1513 1514 static int64_t bdrv_qed_getlength(BlockDriverState *bs) 1515 { 1516 BDRVQEDState *s = bs->opaque; 1517 return s->header.image_size; 1518 } 1519 1520 static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1521 { 1522 BDRVQEDState *s = bs->opaque; 1523 1524 memset(bdi, 0, sizeof(*bdi)); 1525 bdi->cluster_size = s->header.cluster_size; 1526 bdi->is_dirty = s->header.features & QED_F_NEED_CHECK; 1527 bdi->unallocated_blocks_are_zero = true; 1528 bdi->can_write_zeroes_with_unmap = true; 1529 return 0; 1530 } 1531 1532 static int bdrv_qed_change_backing_file(BlockDriverState *bs, 1533 const char *backing_file, 1534 const char *backing_fmt) 1535 { 1536 BDRVQEDState *s = bs->opaque; 1537 QEDHeader new_header, le_header; 1538 void *buffer; 1539 size_t buffer_len, backing_file_len; 1540 int ret; 1541 1542 /* Refuse to set backing filename if unknown compat feature bits are 1543 * active. If the image uses an unknown compat feature then we may not 1544 * know the layout of data following the header structure and cannot safely 1545 * add a new string. 1546 */ 1547 if (backing_file && (s->header.compat_features & 1548 ~QED_COMPAT_FEATURE_MASK)) { 1549 return -ENOTSUP; 1550 } 1551 1552 memcpy(&new_header, &s->header, sizeof(new_header)); 1553 1554 new_header.features &= ~(QED_F_BACKING_FILE | 1555 QED_F_BACKING_FORMAT_NO_PROBE); 1556 1557 /* Adjust feature flags */ 1558 if (backing_file) { 1559 new_header.features |= QED_F_BACKING_FILE; 1560 1561 if (qed_fmt_is_raw(backing_fmt)) { 1562 new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE; 1563 } 1564 } 1565 1566 /* Calculate new header size */ 1567 backing_file_len = 0; 1568 1569 if (backing_file) { 1570 backing_file_len = strlen(backing_file); 1571 } 1572 1573 buffer_len = sizeof(new_header); 1574 new_header.backing_filename_offset = buffer_len; 1575 new_header.backing_filename_size = backing_file_len; 1576 buffer_len += backing_file_len; 1577 1578 /* Make sure we can rewrite header without failing */ 1579 if (buffer_len > new_header.header_size * new_header.cluster_size) { 1580 return -ENOSPC; 1581 } 1582 1583 /* Prepare new header */ 1584 buffer = g_malloc(buffer_len); 1585 1586 qed_header_cpu_to_le(&new_header, &le_header); 1587 memcpy(buffer, &le_header, sizeof(le_header)); 1588 buffer_len = sizeof(le_header); 1589 1590 if (backing_file) { 1591 memcpy(buffer + buffer_len, backing_file, backing_file_len); 1592 buffer_len += backing_file_len; 1593 } 1594 1595 /* Write new header */ 1596 ret = bdrv_pwrite_sync(bs->file->bs, 0, buffer, buffer_len); 1597 g_free(buffer); 1598 if (ret == 0) { 1599 memcpy(&s->header, &new_header, sizeof(new_header)); 1600 } 1601 return ret; 1602 } 1603 1604 static void bdrv_qed_invalidate_cache(BlockDriverState *bs, Error **errp) 1605 { 1606 BDRVQEDState *s = bs->opaque; 1607 Error *local_err = NULL; 1608 int ret; 1609 1610 bdrv_qed_close(bs); 1611 1612 bdrv_invalidate_cache(bs->file->bs, &local_err); 1613 if (local_err) { 1614 error_propagate(errp, local_err); 1615 return; 1616 } 1617 1618 memset(s, 0, sizeof(BDRVQEDState)); 1619 ret = bdrv_qed_open(bs, NULL, bs->open_flags, &local_err); 1620 if (local_err) { 1621 error_propagate(errp, local_err); 1622 error_prepend(errp, "Could not reopen qed layer: "); 1623 return; 1624 } else if (ret < 0) { 1625 error_setg_errno(errp, -ret, "Could not reopen qed layer"); 1626 return; 1627 } 1628 } 1629 1630 static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result, 1631 BdrvCheckMode fix) 1632 { 1633 BDRVQEDState *s = bs->opaque; 1634 1635 return qed_check(s, result, !!fix); 1636 } 1637 1638 static QemuOptsList qed_create_opts = { 1639 .name = "qed-create-opts", 1640 .head = QTAILQ_HEAD_INITIALIZER(qed_create_opts.head), 1641 .desc = { 1642 { 1643 .name = BLOCK_OPT_SIZE, 1644 .type = QEMU_OPT_SIZE, 1645 .help = "Virtual disk size" 1646 }, 1647 { 1648 .name = BLOCK_OPT_BACKING_FILE, 1649 .type = QEMU_OPT_STRING, 1650 .help = "File name of a base image" 1651 }, 1652 { 1653 .name = BLOCK_OPT_BACKING_FMT, 1654 .type = QEMU_OPT_STRING, 1655 .help = "Image format of the base image" 1656 }, 1657 { 1658 .name = BLOCK_OPT_CLUSTER_SIZE, 1659 .type = QEMU_OPT_SIZE, 1660 .help = "Cluster size (in bytes)", 1661 .def_value_str = stringify(QED_DEFAULT_CLUSTER_SIZE) 1662 }, 1663 { 1664 .name = BLOCK_OPT_TABLE_SIZE, 1665 .type = QEMU_OPT_SIZE, 1666 .help = "L1/L2 table size (in clusters)" 1667 }, 1668 { /* end of list */ } 1669 } 1670 }; 1671 1672 static BlockDriver bdrv_qed = { 1673 .format_name = "qed", 1674 .instance_size = sizeof(BDRVQEDState), 1675 .create_opts = &qed_create_opts, 1676 .supports_backing = true, 1677 1678 .bdrv_probe = bdrv_qed_probe, 1679 .bdrv_open = bdrv_qed_open, 1680 .bdrv_close = bdrv_qed_close, 1681 .bdrv_reopen_prepare = bdrv_qed_reopen_prepare, 1682 .bdrv_create = bdrv_qed_create, 1683 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1684 .bdrv_co_get_block_status = bdrv_qed_co_get_block_status, 1685 .bdrv_aio_readv = bdrv_qed_aio_readv, 1686 .bdrv_aio_writev = bdrv_qed_aio_writev, 1687 .bdrv_co_write_zeroes = bdrv_qed_co_write_zeroes, 1688 .bdrv_truncate = bdrv_qed_truncate, 1689 .bdrv_getlength = bdrv_qed_getlength, 1690 .bdrv_get_info = bdrv_qed_get_info, 1691 .bdrv_refresh_limits = bdrv_qed_refresh_limits, 1692 .bdrv_change_backing_file = bdrv_qed_change_backing_file, 1693 .bdrv_invalidate_cache = bdrv_qed_invalidate_cache, 1694 .bdrv_check = bdrv_qed_check, 1695 .bdrv_detach_aio_context = bdrv_qed_detach_aio_context, 1696 .bdrv_attach_aio_context = bdrv_qed_attach_aio_context, 1697 .bdrv_drain = bdrv_qed_drain, 1698 }; 1699 1700 static void bdrv_qed_init(void) 1701 { 1702 bdrv_register(&bdrv_qed); 1703 } 1704 1705 block_init(bdrv_qed_init); 1706