1 /* 2 * Block driver for the QCOW version 2 format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #include "qemu-common.h" 25 #include "block/block_int.h" 26 #include "qemu/module.h" 27 #include <zlib.h> 28 #include "block/qcow2.h" 29 #include "qemu/error-report.h" 30 #include "qapi/qmp/qerror.h" 31 #include "qapi/qmp/qbool.h" 32 #include "qapi/util.h" 33 #include "qapi/qmp/types.h" 34 #include "qapi-event.h" 35 #include "trace.h" 36 #include "qemu/option_int.h" 37 38 /* 39 Differences with QCOW: 40 41 - Support for multiple incremental snapshots. 42 - Memory management by reference counts. 43 - Clusters which have a reference count of one have the bit 44 QCOW_OFLAG_COPIED to optimize write performance. 45 - Size of compressed clusters is stored in sectors to reduce bit usage 46 in the cluster offsets. 47 - Support for storing additional data (such as the VM state) in the 48 snapshots. 49 - If a backing store is used, the cluster size is not constrained 50 (could be backported to QCOW). 51 - L2 tables have always a size of one cluster. 52 */ 53 54 55 typedef struct { 56 uint32_t magic; 57 uint32_t len; 58 } QEMU_PACKED QCowExtension; 59 60 #define QCOW2_EXT_MAGIC_END 0 61 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 62 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 63 64 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 65 { 66 const QCowHeader *cow_header = (const void *)buf; 67 68 if (buf_size >= sizeof(QCowHeader) && 69 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 70 be32_to_cpu(cow_header->version) >= 2) 71 return 100; 72 else 73 return 0; 74 } 75 76 77 /* 78 * read qcow2 extension and fill bs 79 * start reading from start_offset 80 * finish reading upon magic of value 0 or when end_offset reached 81 * unknown magic is skipped (future extension this version knows nothing about) 82 * return 0 upon success, non-0 otherwise 83 */ 84 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 85 uint64_t end_offset, void **p_feature_table, 86 Error **errp) 87 { 88 BDRVQcowState *s = bs->opaque; 89 QCowExtension ext; 90 uint64_t offset; 91 int ret; 92 93 #ifdef DEBUG_EXT 94 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 95 #endif 96 offset = start_offset; 97 while (offset < end_offset) { 98 99 #ifdef DEBUG_EXT 100 /* Sanity check */ 101 if (offset > s->cluster_size) 102 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 103 104 printf("attempting to read extended header in offset %lu\n", offset); 105 #endif 106 107 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 108 if (ret < 0) { 109 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 110 "pread fail from offset %" PRIu64, offset); 111 return 1; 112 } 113 be32_to_cpus(&ext.magic); 114 be32_to_cpus(&ext.len); 115 offset += sizeof(ext); 116 #ifdef DEBUG_EXT 117 printf("ext.magic = 0x%x\n", ext.magic); 118 #endif 119 if (offset > end_offset || ext.len > end_offset - offset) { 120 error_setg(errp, "Header extension too large"); 121 return -EINVAL; 122 } 123 124 switch (ext.magic) { 125 case QCOW2_EXT_MAGIC_END: 126 return 0; 127 128 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 129 if (ext.len >= sizeof(bs->backing_format)) { 130 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 131 " too large (>=%zu)", ext.len, 132 sizeof(bs->backing_format)); 133 return 2; 134 } 135 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 136 if (ret < 0) { 137 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 138 "Could not read format name"); 139 return 3; 140 } 141 bs->backing_format[ext.len] = '\0'; 142 s->image_backing_format = g_strdup(bs->backing_format); 143 #ifdef DEBUG_EXT 144 printf("Qcow2: Got format extension %s\n", bs->backing_format); 145 #endif 146 break; 147 148 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 149 if (p_feature_table != NULL) { 150 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 151 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 152 if (ret < 0) { 153 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 154 "Could not read table"); 155 return ret; 156 } 157 158 *p_feature_table = feature_table; 159 } 160 break; 161 162 default: 163 /* unknown magic - save it in case we need to rewrite the header */ 164 { 165 Qcow2UnknownHeaderExtension *uext; 166 167 uext = g_malloc0(sizeof(*uext) + ext.len); 168 uext->magic = ext.magic; 169 uext->len = ext.len; 170 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 171 172 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 173 if (ret < 0) { 174 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 175 "Could not read data"); 176 return ret; 177 } 178 } 179 break; 180 } 181 182 offset += ((ext.len + 7) & ~7); 183 } 184 185 return 0; 186 } 187 188 static void cleanup_unknown_header_ext(BlockDriverState *bs) 189 { 190 BDRVQcowState *s = bs->opaque; 191 Qcow2UnknownHeaderExtension *uext, *next; 192 193 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 194 QLIST_REMOVE(uext, next); 195 g_free(uext); 196 } 197 } 198 199 static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState *bs, 200 Error **errp, const char *fmt, ...) 201 { 202 char msg[64]; 203 va_list ap; 204 205 va_start(ap, fmt); 206 vsnprintf(msg, sizeof(msg), fmt, ap); 207 va_end(ap); 208 209 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 210 bdrv_get_device_or_node_name(bs), "qcow2", msg); 211 } 212 213 static void report_unsupported_feature(BlockDriverState *bs, 214 Error **errp, Qcow2Feature *table, uint64_t mask) 215 { 216 char *features = g_strdup(""); 217 char *old; 218 219 while (table && table->name[0] != '\0') { 220 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 221 if (mask & (1ULL << table->bit)) { 222 old = features; 223 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 224 table->name); 225 g_free(old); 226 mask &= ~(1ULL << table->bit); 227 } 228 } 229 table++; 230 } 231 232 if (mask) { 233 old = features; 234 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 235 old, *old ? ", " : "", mask); 236 g_free(old); 237 } 238 239 report_unsupported(bs, errp, "%s", features); 240 g_free(features); 241 } 242 243 /* 244 * Sets the dirty bit and flushes afterwards if necessary. 245 * 246 * The incompatible_features bit is only set if the image file header was 247 * updated successfully. Therefore it is not required to check the return 248 * value of this function. 249 */ 250 int qcow2_mark_dirty(BlockDriverState *bs) 251 { 252 BDRVQcowState *s = bs->opaque; 253 uint64_t val; 254 int ret; 255 256 assert(s->qcow_version >= 3); 257 258 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 259 return 0; /* already dirty */ 260 } 261 262 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 263 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 264 &val, sizeof(val)); 265 if (ret < 0) { 266 return ret; 267 } 268 ret = bdrv_flush(bs->file); 269 if (ret < 0) { 270 return ret; 271 } 272 273 /* Only treat image as dirty if the header was updated successfully */ 274 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 275 return 0; 276 } 277 278 /* 279 * Clears the dirty bit and flushes before if necessary. Only call this 280 * function when there are no pending requests, it does not guard against 281 * concurrent requests dirtying the image. 282 */ 283 static int qcow2_mark_clean(BlockDriverState *bs) 284 { 285 BDRVQcowState *s = bs->opaque; 286 287 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 288 int ret; 289 290 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 291 292 ret = bdrv_flush(bs); 293 if (ret < 0) { 294 return ret; 295 } 296 297 return qcow2_update_header(bs); 298 } 299 return 0; 300 } 301 302 /* 303 * Marks the image as corrupt. 304 */ 305 int qcow2_mark_corrupt(BlockDriverState *bs) 306 { 307 BDRVQcowState *s = bs->opaque; 308 309 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 310 return qcow2_update_header(bs); 311 } 312 313 /* 314 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 315 * before if necessary. 316 */ 317 int qcow2_mark_consistent(BlockDriverState *bs) 318 { 319 BDRVQcowState *s = bs->opaque; 320 321 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 322 int ret = bdrv_flush(bs); 323 if (ret < 0) { 324 return ret; 325 } 326 327 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 328 return qcow2_update_header(bs); 329 } 330 return 0; 331 } 332 333 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 334 BdrvCheckMode fix) 335 { 336 int ret = qcow2_check_refcounts(bs, result, fix); 337 if (ret < 0) { 338 return ret; 339 } 340 341 if (fix && result->check_errors == 0 && result->corruptions == 0) { 342 ret = qcow2_mark_clean(bs); 343 if (ret < 0) { 344 return ret; 345 } 346 return qcow2_mark_consistent(bs); 347 } 348 return ret; 349 } 350 351 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 352 uint64_t entries, size_t entry_len) 353 { 354 BDRVQcowState *s = bs->opaque; 355 uint64_t size; 356 357 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 358 * because values will be passed to qemu functions taking int64_t. */ 359 if (entries > INT64_MAX / entry_len) { 360 return -EINVAL; 361 } 362 363 size = entries * entry_len; 364 365 if (INT64_MAX - size < offset) { 366 return -EINVAL; 367 } 368 369 /* Tables must be cluster aligned */ 370 if (offset & (s->cluster_size - 1)) { 371 return -EINVAL; 372 } 373 374 return 0; 375 } 376 377 static QemuOptsList qcow2_runtime_opts = { 378 .name = "qcow2", 379 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 380 .desc = { 381 { 382 .name = QCOW2_OPT_LAZY_REFCOUNTS, 383 .type = QEMU_OPT_BOOL, 384 .help = "Postpone refcount updates", 385 }, 386 { 387 .name = QCOW2_OPT_DISCARD_REQUEST, 388 .type = QEMU_OPT_BOOL, 389 .help = "Pass guest discard requests to the layer below", 390 }, 391 { 392 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 393 .type = QEMU_OPT_BOOL, 394 .help = "Generate discard requests when snapshot related space " 395 "is freed", 396 }, 397 { 398 .name = QCOW2_OPT_DISCARD_OTHER, 399 .type = QEMU_OPT_BOOL, 400 .help = "Generate discard requests when other clusters are freed", 401 }, 402 { 403 .name = QCOW2_OPT_OVERLAP, 404 .type = QEMU_OPT_STRING, 405 .help = "Selects which overlap checks to perform from a range of " 406 "templates (none, constant, cached, all)", 407 }, 408 { 409 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 410 .type = QEMU_OPT_STRING, 411 .help = "Selects which overlap checks to perform from a range of " 412 "templates (none, constant, cached, all)", 413 }, 414 { 415 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 416 .type = QEMU_OPT_BOOL, 417 .help = "Check for unintended writes into the main qcow2 header", 418 }, 419 { 420 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 421 .type = QEMU_OPT_BOOL, 422 .help = "Check for unintended writes into the active L1 table", 423 }, 424 { 425 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 426 .type = QEMU_OPT_BOOL, 427 .help = "Check for unintended writes into an active L2 table", 428 }, 429 { 430 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 431 .type = QEMU_OPT_BOOL, 432 .help = "Check for unintended writes into the refcount table", 433 }, 434 { 435 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 436 .type = QEMU_OPT_BOOL, 437 .help = "Check for unintended writes into a refcount block", 438 }, 439 { 440 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 441 .type = QEMU_OPT_BOOL, 442 .help = "Check for unintended writes into the snapshot table", 443 }, 444 { 445 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 446 .type = QEMU_OPT_BOOL, 447 .help = "Check for unintended writes into an inactive L1 table", 448 }, 449 { 450 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 451 .type = QEMU_OPT_BOOL, 452 .help = "Check for unintended writes into an inactive L2 table", 453 }, 454 { 455 .name = QCOW2_OPT_CACHE_SIZE, 456 .type = QEMU_OPT_SIZE, 457 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 458 "cache size", 459 }, 460 { 461 .name = QCOW2_OPT_L2_CACHE_SIZE, 462 .type = QEMU_OPT_SIZE, 463 .help = "Maximum L2 table cache size", 464 }, 465 { 466 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 467 .type = QEMU_OPT_SIZE, 468 .help = "Maximum refcount block cache size", 469 }, 470 { 471 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 472 .type = QEMU_OPT_NUMBER, 473 .help = "Clean unused cache entries after this time (in seconds)", 474 }, 475 { /* end of list */ } 476 }, 477 }; 478 479 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 480 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 481 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 482 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 483 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 484 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 485 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 486 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 487 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 488 }; 489 490 static void cache_clean_timer_cb(void *opaque) 491 { 492 BlockDriverState *bs = opaque; 493 BDRVQcowState *s = bs->opaque; 494 qcow2_cache_clean_unused(bs, s->l2_table_cache); 495 qcow2_cache_clean_unused(bs, s->refcount_block_cache); 496 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 497 (int64_t) s->cache_clean_interval * 1000); 498 } 499 500 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 501 { 502 BDRVQcowState *s = bs->opaque; 503 if (s->cache_clean_interval > 0) { 504 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 505 SCALE_MS, cache_clean_timer_cb, 506 bs); 507 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 508 (int64_t) s->cache_clean_interval * 1000); 509 } 510 } 511 512 static void cache_clean_timer_del(BlockDriverState *bs) 513 { 514 BDRVQcowState *s = bs->opaque; 515 if (s->cache_clean_timer) { 516 timer_del(s->cache_clean_timer); 517 timer_free(s->cache_clean_timer); 518 s->cache_clean_timer = NULL; 519 } 520 } 521 522 static void qcow2_detach_aio_context(BlockDriverState *bs) 523 { 524 cache_clean_timer_del(bs); 525 } 526 527 static void qcow2_attach_aio_context(BlockDriverState *bs, 528 AioContext *new_context) 529 { 530 cache_clean_timer_init(bs, new_context); 531 } 532 533 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 534 uint64_t *l2_cache_size, 535 uint64_t *refcount_cache_size, Error **errp) 536 { 537 BDRVQcowState *s = bs->opaque; 538 uint64_t combined_cache_size; 539 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 540 541 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 542 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 543 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 544 545 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 546 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 547 *refcount_cache_size = qemu_opt_get_size(opts, 548 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 549 550 if (combined_cache_size_set) { 551 if (l2_cache_size_set && refcount_cache_size_set) { 552 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 553 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 554 "the same time"); 555 return; 556 } else if (*l2_cache_size > combined_cache_size) { 557 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 558 QCOW2_OPT_CACHE_SIZE); 559 return; 560 } else if (*refcount_cache_size > combined_cache_size) { 561 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 562 QCOW2_OPT_CACHE_SIZE); 563 return; 564 } 565 566 if (l2_cache_size_set) { 567 *refcount_cache_size = combined_cache_size - *l2_cache_size; 568 } else if (refcount_cache_size_set) { 569 *l2_cache_size = combined_cache_size - *refcount_cache_size; 570 } else { 571 *refcount_cache_size = combined_cache_size 572 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 573 *l2_cache_size = combined_cache_size - *refcount_cache_size; 574 } 575 } else { 576 if (!l2_cache_size_set && !refcount_cache_size_set) { 577 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 578 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 579 * s->cluster_size); 580 *refcount_cache_size = *l2_cache_size 581 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 582 } else if (!l2_cache_size_set) { 583 *l2_cache_size = *refcount_cache_size 584 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 585 } else if (!refcount_cache_size_set) { 586 *refcount_cache_size = *l2_cache_size 587 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 588 } 589 } 590 } 591 592 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 593 Error **errp) 594 { 595 BDRVQcowState *s = bs->opaque; 596 unsigned int len, i; 597 int ret = 0; 598 QCowHeader header; 599 QemuOpts *opts = NULL; 600 Error *local_err = NULL; 601 uint64_t ext_end; 602 uint64_t l1_vm_state_index; 603 const char *opt_overlap_check, *opt_overlap_check_template; 604 int overlap_check_template = 0; 605 uint64_t l2_cache_size, refcount_cache_size; 606 uint64_t cache_clean_interval; 607 608 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 609 if (ret < 0) { 610 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 611 goto fail; 612 } 613 be32_to_cpus(&header.magic); 614 be32_to_cpus(&header.version); 615 be64_to_cpus(&header.backing_file_offset); 616 be32_to_cpus(&header.backing_file_size); 617 be64_to_cpus(&header.size); 618 be32_to_cpus(&header.cluster_bits); 619 be32_to_cpus(&header.crypt_method); 620 be64_to_cpus(&header.l1_table_offset); 621 be32_to_cpus(&header.l1_size); 622 be64_to_cpus(&header.refcount_table_offset); 623 be32_to_cpus(&header.refcount_table_clusters); 624 be64_to_cpus(&header.snapshots_offset); 625 be32_to_cpus(&header.nb_snapshots); 626 627 if (header.magic != QCOW_MAGIC) { 628 error_setg(errp, "Image is not in qcow2 format"); 629 ret = -EINVAL; 630 goto fail; 631 } 632 if (header.version < 2 || header.version > 3) { 633 report_unsupported(bs, errp, "QCOW version %" PRIu32, header.version); 634 ret = -ENOTSUP; 635 goto fail; 636 } 637 638 s->qcow_version = header.version; 639 640 /* Initialise cluster size */ 641 if (header.cluster_bits < MIN_CLUSTER_BITS || 642 header.cluster_bits > MAX_CLUSTER_BITS) { 643 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 644 header.cluster_bits); 645 ret = -EINVAL; 646 goto fail; 647 } 648 649 s->cluster_bits = header.cluster_bits; 650 s->cluster_size = 1 << s->cluster_bits; 651 s->cluster_sectors = 1 << (s->cluster_bits - 9); 652 653 /* Initialise version 3 header fields */ 654 if (header.version == 2) { 655 header.incompatible_features = 0; 656 header.compatible_features = 0; 657 header.autoclear_features = 0; 658 header.refcount_order = 4; 659 header.header_length = 72; 660 } else { 661 be64_to_cpus(&header.incompatible_features); 662 be64_to_cpus(&header.compatible_features); 663 be64_to_cpus(&header.autoclear_features); 664 be32_to_cpus(&header.refcount_order); 665 be32_to_cpus(&header.header_length); 666 667 if (header.header_length < 104) { 668 error_setg(errp, "qcow2 header too short"); 669 ret = -EINVAL; 670 goto fail; 671 } 672 } 673 674 if (header.header_length > s->cluster_size) { 675 error_setg(errp, "qcow2 header exceeds cluster size"); 676 ret = -EINVAL; 677 goto fail; 678 } 679 680 if (header.header_length > sizeof(header)) { 681 s->unknown_header_fields_size = header.header_length - sizeof(header); 682 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 683 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 684 s->unknown_header_fields_size); 685 if (ret < 0) { 686 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 687 "fields"); 688 goto fail; 689 } 690 } 691 692 if (header.backing_file_offset > s->cluster_size) { 693 error_setg(errp, "Invalid backing file offset"); 694 ret = -EINVAL; 695 goto fail; 696 } 697 698 if (header.backing_file_offset) { 699 ext_end = header.backing_file_offset; 700 } else { 701 ext_end = 1 << header.cluster_bits; 702 } 703 704 /* Handle feature bits */ 705 s->incompatible_features = header.incompatible_features; 706 s->compatible_features = header.compatible_features; 707 s->autoclear_features = header.autoclear_features; 708 709 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 710 void *feature_table = NULL; 711 qcow2_read_extensions(bs, header.header_length, ext_end, 712 &feature_table, NULL); 713 report_unsupported_feature(bs, errp, feature_table, 714 s->incompatible_features & 715 ~QCOW2_INCOMPAT_MASK); 716 ret = -ENOTSUP; 717 g_free(feature_table); 718 goto fail; 719 } 720 721 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 722 /* Corrupt images may not be written to unless they are being repaired 723 */ 724 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 725 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 726 "read/write"); 727 ret = -EACCES; 728 goto fail; 729 } 730 } 731 732 /* Check support for various header values */ 733 if (header.refcount_order > 6) { 734 error_setg(errp, "Reference count entry width too large; may not " 735 "exceed 64 bits"); 736 ret = -EINVAL; 737 goto fail; 738 } 739 s->refcount_order = header.refcount_order; 740 s->refcount_bits = 1 << s->refcount_order; 741 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 742 s->refcount_max += s->refcount_max - 1; 743 744 if (header.crypt_method > QCOW_CRYPT_AES) { 745 error_setg(errp, "Unsupported encryption method: %" PRIu32, 746 header.crypt_method); 747 ret = -EINVAL; 748 goto fail; 749 } 750 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 751 error_setg(errp, "AES cipher not available"); 752 ret = -EINVAL; 753 goto fail; 754 } 755 s->crypt_method_header = header.crypt_method; 756 if (s->crypt_method_header) { 757 bs->encrypted = 1; 758 } 759 760 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 761 s->l2_size = 1 << s->l2_bits; 762 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 763 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 764 s->refcount_block_size = 1 << s->refcount_block_bits; 765 bs->total_sectors = header.size / 512; 766 s->csize_shift = (62 - (s->cluster_bits - 8)); 767 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 768 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 769 770 s->refcount_table_offset = header.refcount_table_offset; 771 s->refcount_table_size = 772 header.refcount_table_clusters << (s->cluster_bits - 3); 773 774 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 775 error_setg(errp, "Reference count table too large"); 776 ret = -EINVAL; 777 goto fail; 778 } 779 780 ret = validate_table_offset(bs, s->refcount_table_offset, 781 s->refcount_table_size, sizeof(uint64_t)); 782 if (ret < 0) { 783 error_setg(errp, "Invalid reference count table offset"); 784 goto fail; 785 } 786 787 /* Snapshot table offset/length */ 788 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 789 error_setg(errp, "Too many snapshots"); 790 ret = -EINVAL; 791 goto fail; 792 } 793 794 ret = validate_table_offset(bs, header.snapshots_offset, 795 header.nb_snapshots, 796 sizeof(QCowSnapshotHeader)); 797 if (ret < 0) { 798 error_setg(errp, "Invalid snapshot table offset"); 799 goto fail; 800 } 801 802 /* read the level 1 table */ 803 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 804 error_setg(errp, "Active L1 table too large"); 805 ret = -EFBIG; 806 goto fail; 807 } 808 s->l1_size = header.l1_size; 809 810 l1_vm_state_index = size_to_l1(s, header.size); 811 if (l1_vm_state_index > INT_MAX) { 812 error_setg(errp, "Image is too big"); 813 ret = -EFBIG; 814 goto fail; 815 } 816 s->l1_vm_state_index = l1_vm_state_index; 817 818 /* the L1 table must contain at least enough entries to put 819 header.size bytes */ 820 if (s->l1_size < s->l1_vm_state_index) { 821 error_setg(errp, "L1 table is too small"); 822 ret = -EINVAL; 823 goto fail; 824 } 825 826 ret = validate_table_offset(bs, header.l1_table_offset, 827 header.l1_size, sizeof(uint64_t)); 828 if (ret < 0) { 829 error_setg(errp, "Invalid L1 table offset"); 830 goto fail; 831 } 832 s->l1_table_offset = header.l1_table_offset; 833 834 835 if (s->l1_size > 0) { 836 s->l1_table = qemu_try_blockalign(bs->file, 837 align_offset(s->l1_size * sizeof(uint64_t), 512)); 838 if (s->l1_table == NULL) { 839 error_setg(errp, "Could not allocate L1 table"); 840 ret = -ENOMEM; 841 goto fail; 842 } 843 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 844 s->l1_size * sizeof(uint64_t)); 845 if (ret < 0) { 846 error_setg_errno(errp, -ret, "Could not read L1 table"); 847 goto fail; 848 } 849 for(i = 0;i < s->l1_size; i++) { 850 be64_to_cpus(&s->l1_table[i]); 851 } 852 } 853 854 /* get L2 table/refcount block cache size from command line options */ 855 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 856 qemu_opts_absorb_qdict(opts, options, &local_err); 857 if (local_err) { 858 error_propagate(errp, local_err); 859 ret = -EINVAL; 860 goto fail; 861 } 862 863 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 864 &local_err); 865 if (local_err) { 866 error_propagate(errp, local_err); 867 ret = -EINVAL; 868 goto fail; 869 } 870 871 l2_cache_size /= s->cluster_size; 872 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 873 l2_cache_size = MIN_L2_CACHE_SIZE; 874 } 875 if (l2_cache_size > INT_MAX) { 876 error_setg(errp, "L2 cache size too big"); 877 ret = -EINVAL; 878 goto fail; 879 } 880 881 refcount_cache_size /= s->cluster_size; 882 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 883 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 884 } 885 if (refcount_cache_size > INT_MAX) { 886 error_setg(errp, "Refcount cache size too big"); 887 ret = -EINVAL; 888 goto fail; 889 } 890 891 /* alloc L2 table/refcount block cache */ 892 s->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 893 s->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 894 if (s->l2_table_cache == NULL || s->refcount_block_cache == NULL) { 895 error_setg(errp, "Could not allocate metadata caches"); 896 ret = -ENOMEM; 897 goto fail; 898 } 899 900 cache_clean_interval = 901 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 0); 902 if (cache_clean_interval > UINT_MAX) { 903 error_setg(errp, "Cache clean interval too big"); 904 ret = -EINVAL; 905 goto fail; 906 } 907 s->cache_clean_interval = cache_clean_interval; 908 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 909 910 s->cluster_cache = g_malloc(s->cluster_size); 911 /* one more sector for decompressed data alignment */ 912 s->cluster_data = qemu_try_blockalign(bs->file, QCOW_MAX_CRYPT_CLUSTERS 913 * s->cluster_size + 512); 914 if (s->cluster_data == NULL) { 915 error_setg(errp, "Could not allocate temporary cluster buffer"); 916 ret = -ENOMEM; 917 goto fail; 918 } 919 920 s->cluster_cache_offset = -1; 921 s->flags = flags; 922 923 ret = qcow2_refcount_init(bs); 924 if (ret != 0) { 925 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 926 goto fail; 927 } 928 929 QLIST_INIT(&s->cluster_allocs); 930 QTAILQ_INIT(&s->discards); 931 932 /* read qcow2 extensions */ 933 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 934 &local_err)) { 935 error_propagate(errp, local_err); 936 ret = -EINVAL; 937 goto fail; 938 } 939 940 /* read the backing file name */ 941 if (header.backing_file_offset != 0) { 942 len = header.backing_file_size; 943 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 944 len >= sizeof(bs->backing_file)) { 945 error_setg(errp, "Backing file name too long"); 946 ret = -EINVAL; 947 goto fail; 948 } 949 ret = bdrv_pread(bs->file, header.backing_file_offset, 950 bs->backing_file, len); 951 if (ret < 0) { 952 error_setg_errno(errp, -ret, "Could not read backing file name"); 953 goto fail; 954 } 955 bs->backing_file[len] = '\0'; 956 s->image_backing_file = g_strdup(bs->backing_file); 957 } 958 959 /* Internal snapshots */ 960 s->snapshots_offset = header.snapshots_offset; 961 s->nb_snapshots = header.nb_snapshots; 962 963 ret = qcow2_read_snapshots(bs); 964 if (ret < 0) { 965 error_setg_errno(errp, -ret, "Could not read snapshots"); 966 goto fail; 967 } 968 969 /* Clear unknown autoclear feature bits */ 970 if (!bs->read_only && !(flags & BDRV_O_INCOMING) && s->autoclear_features) { 971 s->autoclear_features = 0; 972 ret = qcow2_update_header(bs); 973 if (ret < 0) { 974 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 975 goto fail; 976 } 977 } 978 979 /* Initialise locks */ 980 qemu_co_mutex_init(&s->lock); 981 982 /* Repair image if dirty */ 983 if (!(flags & (BDRV_O_CHECK | BDRV_O_INCOMING)) && !bs->read_only && 984 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 985 BdrvCheckResult result = {0}; 986 987 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 988 if (ret < 0) { 989 error_setg_errno(errp, -ret, "Could not repair dirty image"); 990 goto fail; 991 } 992 } 993 994 /* Enable lazy_refcounts according to image and command line options */ 995 s->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 996 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 997 998 s->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 999 s->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 1000 s->discard_passthrough[QCOW2_DISCARD_REQUEST] = 1001 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 1002 flags & BDRV_O_UNMAP); 1003 s->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 1004 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 1005 s->discard_passthrough[QCOW2_DISCARD_OTHER] = 1006 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 1007 1008 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 1009 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 1010 if (opt_overlap_check_template && opt_overlap_check && 1011 strcmp(opt_overlap_check_template, opt_overlap_check)) 1012 { 1013 error_setg(errp, "Conflicting values for qcow2 options '" 1014 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 1015 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 1016 ret = -EINVAL; 1017 goto fail; 1018 } 1019 if (!opt_overlap_check) { 1020 opt_overlap_check = opt_overlap_check_template ?: "cached"; 1021 } 1022 1023 if (!strcmp(opt_overlap_check, "none")) { 1024 overlap_check_template = 0; 1025 } else if (!strcmp(opt_overlap_check, "constant")) { 1026 overlap_check_template = QCOW2_OL_CONSTANT; 1027 } else if (!strcmp(opt_overlap_check, "cached")) { 1028 overlap_check_template = QCOW2_OL_CACHED; 1029 } else if (!strcmp(opt_overlap_check, "all")) { 1030 overlap_check_template = QCOW2_OL_ALL; 1031 } else { 1032 error_setg(errp, "Unsupported value '%s' for qcow2 option " 1033 "'overlap-check'. Allowed are either of the following: " 1034 "none, constant, cached, all", opt_overlap_check); 1035 ret = -EINVAL; 1036 goto fail; 1037 } 1038 1039 s->overlap_check = 0; 1040 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 1041 /* overlap-check defines a template bitmask, but every flag may be 1042 * overwritten through the associated boolean option */ 1043 s->overlap_check |= 1044 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 1045 overlap_check_template & (1 << i)) << i; 1046 } 1047 1048 qemu_opts_del(opts); 1049 opts = NULL; 1050 1051 if (s->use_lazy_refcounts && s->qcow_version < 3) { 1052 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 1053 "qemu 1.1 compatibility level"); 1054 ret = -EINVAL; 1055 goto fail; 1056 } 1057 1058 #ifdef DEBUG_ALLOC 1059 { 1060 BdrvCheckResult result = {0}; 1061 qcow2_check_refcounts(bs, &result, 0); 1062 } 1063 #endif 1064 return ret; 1065 1066 fail: 1067 qemu_opts_del(opts); 1068 g_free(s->unknown_header_fields); 1069 cleanup_unknown_header_ext(bs); 1070 qcow2_free_snapshots(bs); 1071 qcow2_refcount_close(bs); 1072 qemu_vfree(s->l1_table); 1073 /* else pre-write overlap checks in cache_destroy may crash */ 1074 s->l1_table = NULL; 1075 cache_clean_timer_del(bs); 1076 if (s->l2_table_cache) { 1077 qcow2_cache_destroy(bs, s->l2_table_cache); 1078 } 1079 if (s->refcount_block_cache) { 1080 qcow2_cache_destroy(bs, s->refcount_block_cache); 1081 } 1082 g_free(s->cluster_cache); 1083 qemu_vfree(s->cluster_data); 1084 return ret; 1085 } 1086 1087 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1088 { 1089 BDRVQcowState *s = bs->opaque; 1090 1091 bs->bl.write_zeroes_alignment = s->cluster_sectors; 1092 } 1093 1094 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1095 { 1096 BDRVQcowState *s = bs->opaque; 1097 uint8_t keybuf[16]; 1098 int len, i; 1099 Error *err = NULL; 1100 1101 memset(keybuf, 0, 16); 1102 len = strlen(key); 1103 if (len > 16) 1104 len = 16; 1105 /* XXX: we could compress the chars to 7 bits to increase 1106 entropy */ 1107 for(i = 0;i < len;i++) { 1108 keybuf[i] = key[i]; 1109 } 1110 assert(bs->encrypted); 1111 1112 qcrypto_cipher_free(s->cipher); 1113 s->cipher = qcrypto_cipher_new( 1114 QCRYPTO_CIPHER_ALG_AES_128, 1115 QCRYPTO_CIPHER_MODE_CBC, 1116 keybuf, G_N_ELEMENTS(keybuf), 1117 &err); 1118 1119 if (!s->cipher) { 1120 /* XXX would be nice if errors in this method could 1121 * be properly propagate to the caller. Would need 1122 * the bdrv_set_key() API signature to be fixed. */ 1123 error_free(err); 1124 return -1; 1125 } 1126 return 0; 1127 } 1128 1129 /* We have no actual commit/abort logic for qcow2, but we need to write out any 1130 * unwritten data if we reopen read-only. */ 1131 static int qcow2_reopen_prepare(BDRVReopenState *state, 1132 BlockReopenQueue *queue, Error **errp) 1133 { 1134 int ret; 1135 1136 if ((state->flags & BDRV_O_RDWR) == 0) { 1137 ret = bdrv_flush(state->bs); 1138 if (ret < 0) { 1139 return ret; 1140 } 1141 1142 ret = qcow2_mark_clean(state->bs); 1143 if (ret < 0) { 1144 return ret; 1145 } 1146 } 1147 1148 return 0; 1149 } 1150 1151 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1152 int64_t sector_num, int nb_sectors, int *pnum) 1153 { 1154 BDRVQcowState *s = bs->opaque; 1155 uint64_t cluster_offset; 1156 int index_in_cluster, ret; 1157 int64_t status = 0; 1158 1159 *pnum = nb_sectors; 1160 qemu_co_mutex_lock(&s->lock); 1161 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); 1162 qemu_co_mutex_unlock(&s->lock); 1163 if (ret < 0) { 1164 return ret; 1165 } 1166 1167 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1168 !s->cipher) { 1169 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1170 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1171 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1172 } 1173 if (ret == QCOW2_CLUSTER_ZERO) { 1174 status |= BDRV_BLOCK_ZERO; 1175 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1176 status |= BDRV_BLOCK_DATA; 1177 } 1178 return status; 1179 } 1180 1181 /* handle reading after the end of the backing file */ 1182 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1183 int64_t sector_num, int nb_sectors) 1184 { 1185 int n1; 1186 if ((sector_num + nb_sectors) <= bs->total_sectors) 1187 return nb_sectors; 1188 if (sector_num >= bs->total_sectors) 1189 n1 = 0; 1190 else 1191 n1 = bs->total_sectors - sector_num; 1192 1193 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1194 1195 return n1; 1196 } 1197 1198 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1199 int remaining_sectors, QEMUIOVector *qiov) 1200 { 1201 BDRVQcowState *s = bs->opaque; 1202 int index_in_cluster, n1; 1203 int ret; 1204 int cur_nr_sectors; /* number of sectors in current iteration */ 1205 uint64_t cluster_offset = 0; 1206 uint64_t bytes_done = 0; 1207 QEMUIOVector hd_qiov; 1208 uint8_t *cluster_data = NULL; 1209 1210 qemu_iovec_init(&hd_qiov, qiov->niov); 1211 1212 qemu_co_mutex_lock(&s->lock); 1213 1214 while (remaining_sectors != 0) { 1215 1216 /* prepare next request */ 1217 cur_nr_sectors = remaining_sectors; 1218 if (s->cipher) { 1219 cur_nr_sectors = MIN(cur_nr_sectors, 1220 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1221 } 1222 1223 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1224 &cur_nr_sectors, &cluster_offset); 1225 if (ret < 0) { 1226 goto fail; 1227 } 1228 1229 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1230 1231 qemu_iovec_reset(&hd_qiov); 1232 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1233 cur_nr_sectors * 512); 1234 1235 switch (ret) { 1236 case QCOW2_CLUSTER_UNALLOCATED: 1237 1238 if (bs->backing_hd) { 1239 /* read from the base image */ 1240 n1 = qcow2_backing_read1(bs->backing_hd, &hd_qiov, 1241 sector_num, cur_nr_sectors); 1242 if (n1 > 0) { 1243 QEMUIOVector local_qiov; 1244 1245 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1246 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1247 n1 * BDRV_SECTOR_SIZE); 1248 1249 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1250 qemu_co_mutex_unlock(&s->lock); 1251 ret = bdrv_co_readv(bs->backing_hd, sector_num, 1252 n1, &local_qiov); 1253 qemu_co_mutex_lock(&s->lock); 1254 1255 qemu_iovec_destroy(&local_qiov); 1256 1257 if (ret < 0) { 1258 goto fail; 1259 } 1260 } 1261 } else { 1262 /* Note: in this case, no need to wait */ 1263 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1264 } 1265 break; 1266 1267 case QCOW2_CLUSTER_ZERO: 1268 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1269 break; 1270 1271 case QCOW2_CLUSTER_COMPRESSED: 1272 /* add AIO support for compressed blocks ? */ 1273 ret = qcow2_decompress_cluster(bs, cluster_offset); 1274 if (ret < 0) { 1275 goto fail; 1276 } 1277 1278 qemu_iovec_from_buf(&hd_qiov, 0, 1279 s->cluster_cache + index_in_cluster * 512, 1280 512 * cur_nr_sectors); 1281 break; 1282 1283 case QCOW2_CLUSTER_NORMAL: 1284 if ((cluster_offset & 511) != 0) { 1285 ret = -EIO; 1286 goto fail; 1287 } 1288 1289 if (bs->encrypted) { 1290 assert(s->cipher); 1291 1292 /* 1293 * For encrypted images, read everything into a temporary 1294 * contiguous buffer on which the AES functions can work. 1295 */ 1296 if (!cluster_data) { 1297 cluster_data = 1298 qemu_try_blockalign(bs->file, QCOW_MAX_CRYPT_CLUSTERS 1299 * s->cluster_size); 1300 if (cluster_data == NULL) { 1301 ret = -ENOMEM; 1302 goto fail; 1303 } 1304 } 1305 1306 assert(cur_nr_sectors <= 1307 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1308 qemu_iovec_reset(&hd_qiov); 1309 qemu_iovec_add(&hd_qiov, cluster_data, 1310 512 * cur_nr_sectors); 1311 } 1312 1313 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1314 qemu_co_mutex_unlock(&s->lock); 1315 ret = bdrv_co_readv(bs->file, 1316 (cluster_offset >> 9) + index_in_cluster, 1317 cur_nr_sectors, &hd_qiov); 1318 qemu_co_mutex_lock(&s->lock); 1319 if (ret < 0) { 1320 goto fail; 1321 } 1322 if (bs->encrypted) { 1323 assert(s->cipher); 1324 Error *err = NULL; 1325 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1326 cluster_data, cur_nr_sectors, false, 1327 &err) < 0) { 1328 error_free(err); 1329 ret = -EIO; 1330 goto fail; 1331 } 1332 qemu_iovec_from_buf(qiov, bytes_done, 1333 cluster_data, 512 * cur_nr_sectors); 1334 } 1335 break; 1336 1337 default: 1338 g_assert_not_reached(); 1339 ret = -EIO; 1340 goto fail; 1341 } 1342 1343 remaining_sectors -= cur_nr_sectors; 1344 sector_num += cur_nr_sectors; 1345 bytes_done += cur_nr_sectors * 512; 1346 } 1347 ret = 0; 1348 1349 fail: 1350 qemu_co_mutex_unlock(&s->lock); 1351 1352 qemu_iovec_destroy(&hd_qiov); 1353 qemu_vfree(cluster_data); 1354 1355 return ret; 1356 } 1357 1358 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1359 int64_t sector_num, 1360 int remaining_sectors, 1361 QEMUIOVector *qiov) 1362 { 1363 BDRVQcowState *s = bs->opaque; 1364 int index_in_cluster; 1365 int ret; 1366 int cur_nr_sectors; /* number of sectors in current iteration */ 1367 uint64_t cluster_offset; 1368 QEMUIOVector hd_qiov; 1369 uint64_t bytes_done = 0; 1370 uint8_t *cluster_data = NULL; 1371 QCowL2Meta *l2meta = NULL; 1372 1373 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1374 remaining_sectors); 1375 1376 qemu_iovec_init(&hd_qiov, qiov->niov); 1377 1378 s->cluster_cache_offset = -1; /* disable compressed cache */ 1379 1380 qemu_co_mutex_lock(&s->lock); 1381 1382 while (remaining_sectors != 0) { 1383 1384 l2meta = NULL; 1385 1386 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1387 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1388 cur_nr_sectors = remaining_sectors; 1389 if (bs->encrypted && 1390 cur_nr_sectors > 1391 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1392 cur_nr_sectors = 1393 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1394 } 1395 1396 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1397 &cur_nr_sectors, &cluster_offset, &l2meta); 1398 if (ret < 0) { 1399 goto fail; 1400 } 1401 1402 assert((cluster_offset & 511) == 0); 1403 1404 qemu_iovec_reset(&hd_qiov); 1405 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1406 cur_nr_sectors * 512); 1407 1408 if (bs->encrypted) { 1409 Error *err = NULL; 1410 assert(s->cipher); 1411 if (!cluster_data) { 1412 cluster_data = qemu_try_blockalign(bs->file, 1413 QCOW_MAX_CRYPT_CLUSTERS 1414 * s->cluster_size); 1415 if (cluster_data == NULL) { 1416 ret = -ENOMEM; 1417 goto fail; 1418 } 1419 } 1420 1421 assert(hd_qiov.size <= 1422 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1423 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1424 1425 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1426 cluster_data, cur_nr_sectors, 1427 true, &err) < 0) { 1428 error_free(err); 1429 ret = -EIO; 1430 goto fail; 1431 } 1432 1433 qemu_iovec_reset(&hd_qiov); 1434 qemu_iovec_add(&hd_qiov, cluster_data, 1435 cur_nr_sectors * 512); 1436 } 1437 1438 ret = qcow2_pre_write_overlap_check(bs, 0, 1439 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1440 cur_nr_sectors * BDRV_SECTOR_SIZE); 1441 if (ret < 0) { 1442 goto fail; 1443 } 1444 1445 qemu_co_mutex_unlock(&s->lock); 1446 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1447 trace_qcow2_writev_data(qemu_coroutine_self(), 1448 (cluster_offset >> 9) + index_in_cluster); 1449 ret = bdrv_co_writev(bs->file, 1450 (cluster_offset >> 9) + index_in_cluster, 1451 cur_nr_sectors, &hd_qiov); 1452 qemu_co_mutex_lock(&s->lock); 1453 if (ret < 0) { 1454 goto fail; 1455 } 1456 1457 while (l2meta != NULL) { 1458 QCowL2Meta *next; 1459 1460 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1461 if (ret < 0) { 1462 goto fail; 1463 } 1464 1465 /* Take the request off the list of running requests */ 1466 if (l2meta->nb_clusters != 0) { 1467 QLIST_REMOVE(l2meta, next_in_flight); 1468 } 1469 1470 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1471 1472 next = l2meta->next; 1473 g_free(l2meta); 1474 l2meta = next; 1475 } 1476 1477 remaining_sectors -= cur_nr_sectors; 1478 sector_num += cur_nr_sectors; 1479 bytes_done += cur_nr_sectors * 512; 1480 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1481 } 1482 ret = 0; 1483 1484 fail: 1485 qemu_co_mutex_unlock(&s->lock); 1486 1487 while (l2meta != NULL) { 1488 QCowL2Meta *next; 1489 1490 if (l2meta->nb_clusters != 0) { 1491 QLIST_REMOVE(l2meta, next_in_flight); 1492 } 1493 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1494 1495 next = l2meta->next; 1496 g_free(l2meta); 1497 l2meta = next; 1498 } 1499 1500 qemu_iovec_destroy(&hd_qiov); 1501 qemu_vfree(cluster_data); 1502 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1503 1504 return ret; 1505 } 1506 1507 static void qcow2_close(BlockDriverState *bs) 1508 { 1509 BDRVQcowState *s = bs->opaque; 1510 qemu_vfree(s->l1_table); 1511 /* else pre-write overlap checks in cache_destroy may crash */ 1512 s->l1_table = NULL; 1513 1514 if (!(bs->open_flags & BDRV_O_INCOMING)) { 1515 int ret1, ret2; 1516 1517 ret1 = qcow2_cache_flush(bs, s->l2_table_cache); 1518 ret2 = qcow2_cache_flush(bs, s->refcount_block_cache); 1519 1520 if (ret1) { 1521 error_report("Failed to flush the L2 table cache: %s", 1522 strerror(-ret1)); 1523 } 1524 if (ret2) { 1525 error_report("Failed to flush the refcount block cache: %s", 1526 strerror(-ret2)); 1527 } 1528 1529 if (!ret1 && !ret2) { 1530 qcow2_mark_clean(bs); 1531 } 1532 } 1533 1534 cache_clean_timer_del(bs); 1535 qcow2_cache_destroy(bs, s->l2_table_cache); 1536 qcow2_cache_destroy(bs, s->refcount_block_cache); 1537 1538 qcrypto_cipher_free(s->cipher); 1539 s->cipher = NULL; 1540 1541 g_free(s->unknown_header_fields); 1542 cleanup_unknown_header_ext(bs); 1543 1544 g_free(s->image_backing_file); 1545 g_free(s->image_backing_format); 1546 1547 g_free(s->cluster_cache); 1548 qemu_vfree(s->cluster_data); 1549 qcow2_refcount_close(bs); 1550 qcow2_free_snapshots(bs); 1551 } 1552 1553 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1554 { 1555 BDRVQcowState *s = bs->opaque; 1556 int flags = s->flags; 1557 QCryptoCipher *cipher = NULL; 1558 QDict *options; 1559 Error *local_err = NULL; 1560 int ret; 1561 1562 /* 1563 * Backing files are read-only which makes all of their metadata immutable, 1564 * that means we don't have to worry about reopening them here. 1565 */ 1566 1567 cipher = s->cipher; 1568 s->cipher = NULL; 1569 1570 qcow2_close(bs); 1571 1572 bdrv_invalidate_cache(bs->file, &local_err); 1573 if (local_err) { 1574 error_propagate(errp, local_err); 1575 return; 1576 } 1577 1578 memset(s, 0, sizeof(BDRVQcowState)); 1579 options = qdict_clone_shallow(bs->options); 1580 1581 ret = qcow2_open(bs, options, flags, &local_err); 1582 QDECREF(options); 1583 if (local_err) { 1584 error_setg(errp, "Could not reopen qcow2 layer: %s", 1585 error_get_pretty(local_err)); 1586 error_free(local_err); 1587 return; 1588 } else if (ret < 0) { 1589 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1590 return; 1591 } 1592 1593 s->cipher = cipher; 1594 } 1595 1596 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1597 size_t len, size_t buflen) 1598 { 1599 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1600 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1601 1602 if (buflen < ext_len) { 1603 return -ENOSPC; 1604 } 1605 1606 *ext_backing_fmt = (QCowExtension) { 1607 .magic = cpu_to_be32(magic), 1608 .len = cpu_to_be32(len), 1609 }; 1610 memcpy(buf + sizeof(QCowExtension), s, len); 1611 1612 return ext_len; 1613 } 1614 1615 /* 1616 * Updates the qcow2 header, including the variable length parts of it, i.e. 1617 * the backing file name and all extensions. qcow2 was not designed to allow 1618 * such changes, so if we run out of space (we can only use the first cluster) 1619 * this function may fail. 1620 * 1621 * Returns 0 on success, -errno in error cases. 1622 */ 1623 int qcow2_update_header(BlockDriverState *bs) 1624 { 1625 BDRVQcowState *s = bs->opaque; 1626 QCowHeader *header; 1627 char *buf; 1628 size_t buflen = s->cluster_size; 1629 int ret; 1630 uint64_t total_size; 1631 uint32_t refcount_table_clusters; 1632 size_t header_length; 1633 Qcow2UnknownHeaderExtension *uext; 1634 1635 buf = qemu_blockalign(bs, buflen); 1636 1637 /* Header structure */ 1638 header = (QCowHeader*) buf; 1639 1640 if (buflen < sizeof(*header)) { 1641 ret = -ENOSPC; 1642 goto fail; 1643 } 1644 1645 header_length = sizeof(*header) + s->unknown_header_fields_size; 1646 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1647 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1648 1649 *header = (QCowHeader) { 1650 /* Version 2 fields */ 1651 .magic = cpu_to_be32(QCOW_MAGIC), 1652 .version = cpu_to_be32(s->qcow_version), 1653 .backing_file_offset = 0, 1654 .backing_file_size = 0, 1655 .cluster_bits = cpu_to_be32(s->cluster_bits), 1656 .size = cpu_to_be64(total_size), 1657 .crypt_method = cpu_to_be32(s->crypt_method_header), 1658 .l1_size = cpu_to_be32(s->l1_size), 1659 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1660 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1661 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1662 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1663 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1664 1665 /* Version 3 fields */ 1666 .incompatible_features = cpu_to_be64(s->incompatible_features), 1667 .compatible_features = cpu_to_be64(s->compatible_features), 1668 .autoclear_features = cpu_to_be64(s->autoclear_features), 1669 .refcount_order = cpu_to_be32(s->refcount_order), 1670 .header_length = cpu_to_be32(header_length), 1671 }; 1672 1673 /* For older versions, write a shorter header */ 1674 switch (s->qcow_version) { 1675 case 2: 1676 ret = offsetof(QCowHeader, incompatible_features); 1677 break; 1678 case 3: 1679 ret = sizeof(*header); 1680 break; 1681 default: 1682 ret = -EINVAL; 1683 goto fail; 1684 } 1685 1686 buf += ret; 1687 buflen -= ret; 1688 memset(buf, 0, buflen); 1689 1690 /* Preserve any unknown field in the header */ 1691 if (s->unknown_header_fields_size) { 1692 if (buflen < s->unknown_header_fields_size) { 1693 ret = -ENOSPC; 1694 goto fail; 1695 } 1696 1697 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1698 buf += s->unknown_header_fields_size; 1699 buflen -= s->unknown_header_fields_size; 1700 } 1701 1702 /* Backing file format header extension */ 1703 if (s->image_backing_format) { 1704 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1705 s->image_backing_format, 1706 strlen(s->image_backing_format), 1707 buflen); 1708 if (ret < 0) { 1709 goto fail; 1710 } 1711 1712 buf += ret; 1713 buflen -= ret; 1714 } 1715 1716 /* Feature table */ 1717 Qcow2Feature features[] = { 1718 { 1719 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1720 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1721 .name = "dirty bit", 1722 }, 1723 { 1724 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1725 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1726 .name = "corrupt bit", 1727 }, 1728 { 1729 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1730 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1731 .name = "lazy refcounts", 1732 }, 1733 }; 1734 1735 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1736 features, sizeof(features), buflen); 1737 if (ret < 0) { 1738 goto fail; 1739 } 1740 buf += ret; 1741 buflen -= ret; 1742 1743 /* Keep unknown header extensions */ 1744 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1745 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1746 if (ret < 0) { 1747 goto fail; 1748 } 1749 1750 buf += ret; 1751 buflen -= ret; 1752 } 1753 1754 /* End of header extensions */ 1755 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1756 if (ret < 0) { 1757 goto fail; 1758 } 1759 1760 buf += ret; 1761 buflen -= ret; 1762 1763 /* Backing file name */ 1764 if (s->image_backing_file) { 1765 size_t backing_file_len = strlen(s->image_backing_file); 1766 1767 if (buflen < backing_file_len) { 1768 ret = -ENOSPC; 1769 goto fail; 1770 } 1771 1772 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1773 strncpy(buf, s->image_backing_file, buflen); 1774 1775 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1776 header->backing_file_size = cpu_to_be32(backing_file_len); 1777 } 1778 1779 /* Write the new header */ 1780 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 1781 if (ret < 0) { 1782 goto fail; 1783 } 1784 1785 ret = 0; 1786 fail: 1787 qemu_vfree(header); 1788 return ret; 1789 } 1790 1791 static int qcow2_change_backing_file(BlockDriverState *bs, 1792 const char *backing_file, const char *backing_fmt) 1793 { 1794 BDRVQcowState *s = bs->opaque; 1795 1796 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1797 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1798 1799 g_free(s->image_backing_file); 1800 g_free(s->image_backing_format); 1801 1802 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 1803 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 1804 1805 return qcow2_update_header(bs); 1806 } 1807 1808 static int preallocate(BlockDriverState *bs) 1809 { 1810 uint64_t nb_sectors; 1811 uint64_t offset; 1812 uint64_t host_offset = 0; 1813 int num; 1814 int ret; 1815 QCowL2Meta *meta; 1816 1817 nb_sectors = bdrv_nb_sectors(bs); 1818 offset = 0; 1819 1820 while (nb_sectors) { 1821 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 1822 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 1823 &host_offset, &meta); 1824 if (ret < 0) { 1825 return ret; 1826 } 1827 1828 while (meta) { 1829 QCowL2Meta *next = meta->next; 1830 1831 ret = qcow2_alloc_cluster_link_l2(bs, meta); 1832 if (ret < 0) { 1833 qcow2_free_any_clusters(bs, meta->alloc_offset, 1834 meta->nb_clusters, QCOW2_DISCARD_NEVER); 1835 return ret; 1836 } 1837 1838 /* There are no dependent requests, but we need to remove our 1839 * request from the list of in-flight requests */ 1840 QLIST_REMOVE(meta, next_in_flight); 1841 1842 g_free(meta); 1843 meta = next; 1844 } 1845 1846 /* TODO Preallocate data if requested */ 1847 1848 nb_sectors -= num; 1849 offset += num << BDRV_SECTOR_BITS; 1850 } 1851 1852 /* 1853 * It is expected that the image file is large enough to actually contain 1854 * all of the allocated clusters (otherwise we get failing reads after 1855 * EOF). Extend the image to the last allocated sector. 1856 */ 1857 if (host_offset != 0) { 1858 uint8_t buf[BDRV_SECTOR_SIZE]; 1859 memset(buf, 0, BDRV_SECTOR_SIZE); 1860 ret = bdrv_write(bs->file, (host_offset >> BDRV_SECTOR_BITS) + num - 1, 1861 buf, 1); 1862 if (ret < 0) { 1863 return ret; 1864 } 1865 } 1866 1867 return 0; 1868 } 1869 1870 static int qcow2_create2(const char *filename, int64_t total_size, 1871 const char *backing_file, const char *backing_format, 1872 int flags, size_t cluster_size, PreallocMode prealloc, 1873 QemuOpts *opts, int version, int refcount_order, 1874 Error **errp) 1875 { 1876 /* Calculate cluster_bits */ 1877 int cluster_bits; 1878 cluster_bits = ctz32(cluster_size); 1879 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 1880 (1 << cluster_bits) != cluster_size) 1881 { 1882 error_setg(errp, "Cluster size must be a power of two between %d and " 1883 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 1884 return -EINVAL; 1885 } 1886 1887 /* 1888 * Open the image file and write a minimal qcow2 header. 1889 * 1890 * We keep things simple and start with a zero-sized image. We also 1891 * do without refcount blocks or a L1 table for now. We'll fix the 1892 * inconsistency later. 1893 * 1894 * We do need a refcount table because growing the refcount table means 1895 * allocating two new refcount blocks - the seconds of which would be at 1896 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 1897 * size for any qcow2 image. 1898 */ 1899 BlockDriverState* bs; 1900 QCowHeader *header; 1901 uint64_t* refcount_table; 1902 Error *local_err = NULL; 1903 int ret; 1904 1905 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 1906 /* Note: The following calculation does not need to be exact; if it is a 1907 * bit off, either some bytes will be "leaked" (which is fine) or we 1908 * will need to increase the file size by some bytes (which is fine, 1909 * too, as long as the bulk is allocated here). Therefore, using 1910 * floating point arithmetic is fine. */ 1911 int64_t meta_size = 0; 1912 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 1913 int64_t aligned_total_size = align_offset(total_size, cluster_size); 1914 int refblock_bits, refblock_size; 1915 /* refcount entry size in bytes */ 1916 double rces = (1 << refcount_order) / 8.; 1917 1918 /* see qcow2_open() */ 1919 refblock_bits = cluster_bits - (refcount_order - 3); 1920 refblock_size = 1 << refblock_bits; 1921 1922 /* header: 1 cluster */ 1923 meta_size += cluster_size; 1924 1925 /* total size of L2 tables */ 1926 nl2e = aligned_total_size / cluster_size; 1927 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 1928 meta_size += nl2e * sizeof(uint64_t); 1929 1930 /* total size of L1 tables */ 1931 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 1932 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 1933 meta_size += nl1e * sizeof(uint64_t); 1934 1935 /* total size of refcount blocks 1936 * 1937 * note: every host cluster is reference-counted, including metadata 1938 * (even refcount blocks are recursively included). 1939 * Let: 1940 * a = total_size (this is the guest disk size) 1941 * m = meta size not including refcount blocks and refcount tables 1942 * c = cluster size 1943 * y1 = number of refcount blocks entries 1944 * y2 = meta size including everything 1945 * rces = refcount entry size in bytes 1946 * then, 1947 * y1 = (y2 + a)/c 1948 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 1949 * we can get y1: 1950 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 1951 */ 1952 nrefblocke = (aligned_total_size + meta_size + cluster_size) 1953 / (cluster_size - rces - rces * sizeof(uint64_t) 1954 / cluster_size); 1955 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 1956 1957 /* total size of refcount tables */ 1958 nreftablee = nrefblocke / refblock_size; 1959 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 1960 meta_size += nreftablee * sizeof(uint64_t); 1961 1962 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 1963 aligned_total_size + meta_size, &error_abort); 1964 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 1965 &error_abort); 1966 } 1967 1968 ret = bdrv_create_file(filename, opts, &local_err); 1969 if (ret < 0) { 1970 error_propagate(errp, local_err); 1971 return ret; 1972 } 1973 1974 bs = NULL; 1975 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 1976 NULL, &local_err); 1977 if (ret < 0) { 1978 error_propagate(errp, local_err); 1979 return ret; 1980 } 1981 1982 /* Write the header */ 1983 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 1984 header = g_malloc0(cluster_size); 1985 *header = (QCowHeader) { 1986 .magic = cpu_to_be32(QCOW_MAGIC), 1987 .version = cpu_to_be32(version), 1988 .cluster_bits = cpu_to_be32(cluster_bits), 1989 .size = cpu_to_be64(0), 1990 .l1_table_offset = cpu_to_be64(0), 1991 .l1_size = cpu_to_be32(0), 1992 .refcount_table_offset = cpu_to_be64(cluster_size), 1993 .refcount_table_clusters = cpu_to_be32(1), 1994 .refcount_order = cpu_to_be32(refcount_order), 1995 .header_length = cpu_to_be32(sizeof(*header)), 1996 }; 1997 1998 if (flags & BLOCK_FLAG_ENCRYPT) { 1999 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2000 } else { 2001 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2002 } 2003 2004 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2005 header->compatible_features |= 2006 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2007 } 2008 2009 ret = bdrv_pwrite(bs, 0, header, cluster_size); 2010 g_free(header); 2011 if (ret < 0) { 2012 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2013 goto out; 2014 } 2015 2016 /* Write a refcount table with one refcount block */ 2017 refcount_table = g_malloc0(2 * cluster_size); 2018 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2019 ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size); 2020 g_free(refcount_table); 2021 2022 if (ret < 0) { 2023 error_setg_errno(errp, -ret, "Could not write refcount table"); 2024 goto out; 2025 } 2026 2027 bdrv_unref(bs); 2028 bs = NULL; 2029 2030 /* 2031 * And now open the image and make it consistent first (i.e. increase the 2032 * refcount of the cluster that is occupied by the header and the refcount 2033 * table) 2034 */ 2035 ret = bdrv_open(&bs, filename, NULL, NULL, 2036 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, 2037 &bdrv_qcow2, &local_err); 2038 if (ret < 0) { 2039 error_propagate(errp, local_err); 2040 goto out; 2041 } 2042 2043 ret = qcow2_alloc_clusters(bs, 3 * cluster_size); 2044 if (ret < 0) { 2045 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2046 "header and refcount table"); 2047 goto out; 2048 2049 } else if (ret != 0) { 2050 error_report("Huh, first cluster in empty image is already in use?"); 2051 abort(); 2052 } 2053 2054 /* Okay, now that we have a valid image, let's give it the right size */ 2055 ret = bdrv_truncate(bs, total_size); 2056 if (ret < 0) { 2057 error_setg_errno(errp, -ret, "Could not resize image"); 2058 goto out; 2059 } 2060 2061 /* Want a backing file? There you go.*/ 2062 if (backing_file) { 2063 ret = bdrv_change_backing_file(bs, backing_file, backing_format); 2064 if (ret < 0) { 2065 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2066 "with format '%s'", backing_file, backing_format); 2067 goto out; 2068 } 2069 } 2070 2071 /* And if we're supposed to preallocate metadata, do that now */ 2072 if (prealloc != PREALLOC_MODE_OFF) { 2073 BDRVQcowState *s = bs->opaque; 2074 qemu_co_mutex_lock(&s->lock); 2075 ret = preallocate(bs); 2076 qemu_co_mutex_unlock(&s->lock); 2077 if (ret < 0) { 2078 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2079 goto out; 2080 } 2081 } 2082 2083 bdrv_unref(bs); 2084 bs = NULL; 2085 2086 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2087 ret = bdrv_open(&bs, filename, NULL, NULL, 2088 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, 2089 &bdrv_qcow2, &local_err); 2090 if (local_err) { 2091 error_propagate(errp, local_err); 2092 goto out; 2093 } 2094 2095 ret = 0; 2096 out: 2097 if (bs) { 2098 bdrv_unref(bs); 2099 } 2100 return ret; 2101 } 2102 2103 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2104 { 2105 char *backing_file = NULL; 2106 char *backing_fmt = NULL; 2107 char *buf = NULL; 2108 uint64_t size = 0; 2109 int flags = 0; 2110 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2111 PreallocMode prealloc; 2112 int version = 3; 2113 uint64_t refcount_bits = 16; 2114 int refcount_order; 2115 Error *local_err = NULL; 2116 int ret; 2117 2118 /* Read out options */ 2119 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2120 BDRV_SECTOR_SIZE); 2121 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2122 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2123 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2124 flags |= BLOCK_FLAG_ENCRYPT; 2125 } 2126 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2127 DEFAULT_CLUSTER_SIZE); 2128 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2129 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2130 PREALLOC_MODE_MAX, PREALLOC_MODE_OFF, 2131 &local_err); 2132 if (local_err) { 2133 error_propagate(errp, local_err); 2134 ret = -EINVAL; 2135 goto finish; 2136 } 2137 g_free(buf); 2138 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2139 if (!buf) { 2140 /* keep the default */ 2141 } else if (!strcmp(buf, "0.10")) { 2142 version = 2; 2143 } else if (!strcmp(buf, "1.1")) { 2144 version = 3; 2145 } else { 2146 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2147 ret = -EINVAL; 2148 goto finish; 2149 } 2150 2151 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2152 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2153 } 2154 2155 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2156 error_setg(errp, "Backing file and preallocation cannot be used at " 2157 "the same time"); 2158 ret = -EINVAL; 2159 goto finish; 2160 } 2161 2162 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2163 error_setg(errp, "Lazy refcounts only supported with compatibility " 2164 "level 1.1 and above (use compat=1.1 or greater)"); 2165 ret = -EINVAL; 2166 goto finish; 2167 } 2168 2169 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2170 refcount_bits); 2171 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2172 error_setg(errp, "Refcount width must be a power of two and may not " 2173 "exceed 64 bits"); 2174 ret = -EINVAL; 2175 goto finish; 2176 } 2177 2178 if (version < 3 && refcount_bits != 16) { 2179 error_setg(errp, "Different refcount widths than 16 bits require " 2180 "compatibility level 1.1 or above (use compat=1.1 or " 2181 "greater)"); 2182 ret = -EINVAL; 2183 goto finish; 2184 } 2185 2186 refcount_order = ctz32(refcount_bits); 2187 2188 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2189 cluster_size, prealloc, opts, version, refcount_order, 2190 &local_err); 2191 if (local_err) { 2192 error_propagate(errp, local_err); 2193 } 2194 2195 finish: 2196 g_free(backing_file); 2197 g_free(backing_fmt); 2198 g_free(buf); 2199 return ret; 2200 } 2201 2202 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2203 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2204 { 2205 int ret; 2206 BDRVQcowState *s = bs->opaque; 2207 2208 /* Emulate misaligned zero writes */ 2209 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { 2210 return -ENOTSUP; 2211 } 2212 2213 /* Whatever is left can use real zero clusters */ 2214 qemu_co_mutex_lock(&s->lock); 2215 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2216 nb_sectors); 2217 qemu_co_mutex_unlock(&s->lock); 2218 2219 return ret; 2220 } 2221 2222 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2223 int64_t sector_num, int nb_sectors) 2224 { 2225 int ret; 2226 BDRVQcowState *s = bs->opaque; 2227 2228 qemu_co_mutex_lock(&s->lock); 2229 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2230 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2231 qemu_co_mutex_unlock(&s->lock); 2232 return ret; 2233 } 2234 2235 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2236 { 2237 BDRVQcowState *s = bs->opaque; 2238 int64_t new_l1_size; 2239 int ret; 2240 2241 if (offset & 511) { 2242 error_report("The new size must be a multiple of 512"); 2243 return -EINVAL; 2244 } 2245 2246 /* cannot proceed if image has snapshots */ 2247 if (s->nb_snapshots) { 2248 error_report("Can't resize an image which has snapshots"); 2249 return -ENOTSUP; 2250 } 2251 2252 /* shrinking is currently not supported */ 2253 if (offset < bs->total_sectors * 512) { 2254 error_report("qcow2 doesn't support shrinking images yet"); 2255 return -ENOTSUP; 2256 } 2257 2258 new_l1_size = size_to_l1(s, offset); 2259 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2260 if (ret < 0) { 2261 return ret; 2262 } 2263 2264 /* write updated header.size */ 2265 offset = cpu_to_be64(offset); 2266 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 2267 &offset, sizeof(uint64_t)); 2268 if (ret < 0) { 2269 return ret; 2270 } 2271 2272 s->l1_vm_state_index = new_l1_size; 2273 return 0; 2274 } 2275 2276 /* XXX: put compressed sectors first, then all the cluster aligned 2277 tables to avoid losing bytes in alignment */ 2278 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2279 const uint8_t *buf, int nb_sectors) 2280 { 2281 BDRVQcowState *s = bs->opaque; 2282 z_stream strm; 2283 int ret, out_len; 2284 uint8_t *out_buf; 2285 uint64_t cluster_offset; 2286 2287 if (nb_sectors == 0) { 2288 /* align end of file to a sector boundary to ease reading with 2289 sector based I/Os */ 2290 cluster_offset = bdrv_getlength(bs->file); 2291 return bdrv_truncate(bs->file, cluster_offset); 2292 } 2293 2294 if (nb_sectors != s->cluster_sectors) { 2295 ret = -EINVAL; 2296 2297 /* Zero-pad last write if image size is not cluster aligned */ 2298 if (sector_num + nb_sectors == bs->total_sectors && 2299 nb_sectors < s->cluster_sectors) { 2300 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2301 memset(pad_buf, 0, s->cluster_size); 2302 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2303 ret = qcow2_write_compressed(bs, sector_num, 2304 pad_buf, s->cluster_sectors); 2305 qemu_vfree(pad_buf); 2306 } 2307 return ret; 2308 } 2309 2310 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2311 2312 /* best compression, small window, no zlib header */ 2313 memset(&strm, 0, sizeof(strm)); 2314 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2315 Z_DEFLATED, -12, 2316 9, Z_DEFAULT_STRATEGY); 2317 if (ret != 0) { 2318 ret = -EINVAL; 2319 goto fail; 2320 } 2321 2322 strm.avail_in = s->cluster_size; 2323 strm.next_in = (uint8_t *)buf; 2324 strm.avail_out = s->cluster_size; 2325 strm.next_out = out_buf; 2326 2327 ret = deflate(&strm, Z_FINISH); 2328 if (ret != Z_STREAM_END && ret != Z_OK) { 2329 deflateEnd(&strm); 2330 ret = -EINVAL; 2331 goto fail; 2332 } 2333 out_len = strm.next_out - out_buf; 2334 2335 deflateEnd(&strm); 2336 2337 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2338 /* could not compress: write normal cluster */ 2339 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2340 if (ret < 0) { 2341 goto fail; 2342 } 2343 } else { 2344 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2345 sector_num << 9, out_len); 2346 if (!cluster_offset) { 2347 ret = -EIO; 2348 goto fail; 2349 } 2350 cluster_offset &= s->cluster_offset_mask; 2351 2352 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2353 if (ret < 0) { 2354 goto fail; 2355 } 2356 2357 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2358 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 2359 if (ret < 0) { 2360 goto fail; 2361 } 2362 } 2363 2364 ret = 0; 2365 fail: 2366 g_free(out_buf); 2367 return ret; 2368 } 2369 2370 static int make_completely_empty(BlockDriverState *bs) 2371 { 2372 BDRVQcowState *s = bs->opaque; 2373 int ret, l1_clusters; 2374 int64_t offset; 2375 uint64_t *new_reftable = NULL; 2376 uint64_t rt_entry, l1_size2; 2377 struct { 2378 uint64_t l1_offset; 2379 uint64_t reftable_offset; 2380 uint32_t reftable_clusters; 2381 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2382 2383 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2384 if (ret < 0) { 2385 goto fail; 2386 } 2387 2388 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2389 if (ret < 0) { 2390 goto fail; 2391 } 2392 2393 /* Refcounts will be broken utterly */ 2394 ret = qcow2_mark_dirty(bs); 2395 if (ret < 0) { 2396 goto fail; 2397 } 2398 2399 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2400 2401 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2402 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2403 2404 /* After this call, neither the in-memory nor the on-disk refcount 2405 * information accurately describe the actual references */ 2406 2407 ret = bdrv_write_zeroes(bs->file, s->l1_table_offset / BDRV_SECTOR_SIZE, 2408 l1_clusters * s->cluster_sectors, 0); 2409 if (ret < 0) { 2410 goto fail_broken_refcounts; 2411 } 2412 memset(s->l1_table, 0, l1_size2); 2413 2414 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2415 2416 /* Overwrite enough clusters at the beginning of the sectors to place 2417 * the refcount table, a refcount block and the L1 table in; this may 2418 * overwrite parts of the existing refcount and L1 table, which is not 2419 * an issue because the dirty flag is set, complete data loss is in fact 2420 * desired and partial data loss is consequently fine as well */ 2421 ret = bdrv_write_zeroes(bs->file, s->cluster_size / BDRV_SECTOR_SIZE, 2422 (2 + l1_clusters) * s->cluster_size / 2423 BDRV_SECTOR_SIZE, 0); 2424 /* This call (even if it failed overall) may have overwritten on-disk 2425 * refcount structures; in that case, the in-memory refcount information 2426 * will probably differ from the on-disk information which makes the BDS 2427 * unusable */ 2428 if (ret < 0) { 2429 goto fail_broken_refcounts; 2430 } 2431 2432 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2433 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2434 2435 /* "Create" an empty reftable (one cluster) directly after the image 2436 * header and an empty L1 table three clusters after the image header; 2437 * the cluster between those two will be used as the first refblock */ 2438 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2439 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2440 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2441 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 2442 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2443 if (ret < 0) { 2444 goto fail_broken_refcounts; 2445 } 2446 2447 s->l1_table_offset = 3 * s->cluster_size; 2448 2449 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2450 if (!new_reftable) { 2451 ret = -ENOMEM; 2452 goto fail_broken_refcounts; 2453 } 2454 2455 s->refcount_table_offset = s->cluster_size; 2456 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2457 2458 g_free(s->refcount_table); 2459 s->refcount_table = new_reftable; 2460 new_reftable = NULL; 2461 2462 /* Now the in-memory refcount information again corresponds to the on-disk 2463 * information (reftable is empty and no refblocks (the refblock cache is 2464 * empty)); however, this means some clusters (e.g. the image header) are 2465 * referenced, but not refcounted, but the normal qcow2 code assumes that 2466 * the in-memory information is always correct */ 2467 2468 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2469 2470 /* Enter the first refblock into the reftable */ 2471 rt_entry = cpu_to_be64(2 * s->cluster_size); 2472 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 2473 &rt_entry, sizeof(rt_entry)); 2474 if (ret < 0) { 2475 goto fail_broken_refcounts; 2476 } 2477 s->refcount_table[0] = 2 * s->cluster_size; 2478 2479 s->free_cluster_index = 0; 2480 assert(3 + l1_clusters <= s->refcount_block_size); 2481 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2482 if (offset < 0) { 2483 ret = offset; 2484 goto fail_broken_refcounts; 2485 } else if (offset > 0) { 2486 error_report("First cluster in emptied image is in use"); 2487 abort(); 2488 } 2489 2490 /* Now finally the in-memory information corresponds to the on-disk 2491 * structures and is correct */ 2492 ret = qcow2_mark_clean(bs); 2493 if (ret < 0) { 2494 goto fail; 2495 } 2496 2497 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size); 2498 if (ret < 0) { 2499 goto fail; 2500 } 2501 2502 return 0; 2503 2504 fail_broken_refcounts: 2505 /* The BDS is unusable at this point. If we wanted to make it usable, we 2506 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2507 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2508 * again. However, because the functions which could have caused this error 2509 * path to be taken are used by those functions as well, it's very likely 2510 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2511 bs->drv = NULL; 2512 2513 fail: 2514 g_free(new_reftable); 2515 return ret; 2516 } 2517 2518 static int qcow2_make_empty(BlockDriverState *bs) 2519 { 2520 BDRVQcowState *s = bs->opaque; 2521 uint64_t start_sector; 2522 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2523 int l1_clusters, ret = 0; 2524 2525 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2526 2527 if (s->qcow_version >= 3 && !s->snapshots && 2528 3 + l1_clusters <= s->refcount_block_size) { 2529 /* The following function only works for qcow2 v3 images (it requires 2530 * the dirty flag) and only as long as there are no snapshots (because 2531 * it completely empties the image). Furthermore, the L1 table and three 2532 * additional clusters (image header, refcount table, one refcount 2533 * block) have to fit inside one refcount block. */ 2534 return make_completely_empty(bs); 2535 } 2536 2537 /* This fallback code simply discards every active cluster; this is slow, 2538 * but works in all cases */ 2539 for (start_sector = 0; start_sector < bs->total_sectors; 2540 start_sector += sector_step) 2541 { 2542 /* As this function is generally used after committing an external 2543 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2544 * default action for this kind of discard is to pass the discard, 2545 * which will ideally result in an actually smaller image file, as 2546 * is probably desired. */ 2547 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2548 MIN(sector_step, 2549 bs->total_sectors - start_sector), 2550 QCOW2_DISCARD_SNAPSHOT, true); 2551 if (ret < 0) { 2552 break; 2553 } 2554 } 2555 2556 return ret; 2557 } 2558 2559 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2560 { 2561 BDRVQcowState *s = bs->opaque; 2562 int ret; 2563 2564 qemu_co_mutex_lock(&s->lock); 2565 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2566 if (ret < 0) { 2567 qemu_co_mutex_unlock(&s->lock); 2568 return ret; 2569 } 2570 2571 if (qcow2_need_accurate_refcounts(s)) { 2572 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2573 if (ret < 0) { 2574 qemu_co_mutex_unlock(&s->lock); 2575 return ret; 2576 } 2577 } 2578 qemu_co_mutex_unlock(&s->lock); 2579 2580 return 0; 2581 } 2582 2583 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2584 { 2585 BDRVQcowState *s = bs->opaque; 2586 bdi->unallocated_blocks_are_zero = true; 2587 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2588 bdi->cluster_size = s->cluster_size; 2589 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2590 return 0; 2591 } 2592 2593 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2594 { 2595 BDRVQcowState *s = bs->opaque; 2596 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2597 2598 *spec_info = (ImageInfoSpecific){ 2599 .kind = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2600 { 2601 .qcow2 = g_new(ImageInfoSpecificQCow2, 1), 2602 }, 2603 }; 2604 if (s->qcow_version == 2) { 2605 *spec_info->qcow2 = (ImageInfoSpecificQCow2){ 2606 .compat = g_strdup("0.10"), 2607 .refcount_bits = s->refcount_bits, 2608 }; 2609 } else if (s->qcow_version == 3) { 2610 *spec_info->qcow2 = (ImageInfoSpecificQCow2){ 2611 .compat = g_strdup("1.1"), 2612 .lazy_refcounts = s->compatible_features & 2613 QCOW2_COMPAT_LAZY_REFCOUNTS, 2614 .has_lazy_refcounts = true, 2615 .corrupt = s->incompatible_features & 2616 QCOW2_INCOMPAT_CORRUPT, 2617 .has_corrupt = true, 2618 .refcount_bits = s->refcount_bits, 2619 }; 2620 } 2621 2622 return spec_info; 2623 } 2624 2625 #if 0 2626 static void dump_refcounts(BlockDriverState *bs) 2627 { 2628 BDRVQcowState *s = bs->opaque; 2629 int64_t nb_clusters, k, k1, size; 2630 int refcount; 2631 2632 size = bdrv_getlength(bs->file); 2633 nb_clusters = size_to_clusters(s, size); 2634 for(k = 0; k < nb_clusters;) { 2635 k1 = k; 2636 refcount = get_refcount(bs, k); 2637 k++; 2638 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2639 k++; 2640 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2641 k - k1); 2642 } 2643 } 2644 #endif 2645 2646 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2647 int64_t pos) 2648 { 2649 BDRVQcowState *s = bs->opaque; 2650 int64_t total_sectors = bs->total_sectors; 2651 bool zero_beyond_eof = bs->zero_beyond_eof; 2652 int ret; 2653 2654 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2655 bs->zero_beyond_eof = false; 2656 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2657 bs->zero_beyond_eof = zero_beyond_eof; 2658 2659 /* bdrv_co_do_writev will have increased the total_sectors value to include 2660 * the VM state - the VM state is however not an actual part of the block 2661 * device, therefore, we need to restore the old value. */ 2662 bs->total_sectors = total_sectors; 2663 2664 return ret; 2665 } 2666 2667 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2668 int64_t pos, int size) 2669 { 2670 BDRVQcowState *s = bs->opaque; 2671 bool zero_beyond_eof = bs->zero_beyond_eof; 2672 int ret; 2673 2674 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2675 bs->zero_beyond_eof = false; 2676 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2677 bs->zero_beyond_eof = zero_beyond_eof; 2678 2679 return ret; 2680 } 2681 2682 /* 2683 * Downgrades an image's version. To achieve this, any incompatible features 2684 * have to be removed. 2685 */ 2686 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2687 BlockDriverAmendStatusCB *status_cb) 2688 { 2689 BDRVQcowState *s = bs->opaque; 2690 int current_version = s->qcow_version; 2691 int ret; 2692 2693 if (target_version == current_version) { 2694 return 0; 2695 } else if (target_version > current_version) { 2696 return -EINVAL; 2697 } else if (target_version != 2) { 2698 return -EINVAL; 2699 } 2700 2701 if (s->refcount_order != 4) { 2702 /* we would have to convert the image to a refcount_order == 4 image 2703 * here; however, since qemu (at the time of writing this) does not 2704 * support anything different than 4 anyway, there is no point in doing 2705 * so right now; however, we should error out (if qemu supports this in 2706 * the future and this code has not been adapted) */ 2707 error_report("qcow2_downgrade: Image refcount orders other than 4 are " 2708 "currently not supported."); 2709 return -ENOTSUP; 2710 } 2711 2712 /* clear incompatible features */ 2713 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2714 ret = qcow2_mark_clean(bs); 2715 if (ret < 0) { 2716 return ret; 2717 } 2718 } 2719 2720 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2721 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2722 * best thing to do anyway */ 2723 2724 if (s->incompatible_features) { 2725 return -ENOTSUP; 2726 } 2727 2728 /* since we can ignore compatible features, we can set them to 0 as well */ 2729 s->compatible_features = 0; 2730 /* if lazy refcounts have been used, they have already been fixed through 2731 * clearing the dirty flag */ 2732 2733 /* clearing autoclear features is trivial */ 2734 s->autoclear_features = 0; 2735 2736 ret = qcow2_expand_zero_clusters(bs, status_cb); 2737 if (ret < 0) { 2738 return ret; 2739 } 2740 2741 s->qcow_version = target_version; 2742 ret = qcow2_update_header(bs); 2743 if (ret < 0) { 2744 s->qcow_version = current_version; 2745 return ret; 2746 } 2747 return 0; 2748 } 2749 2750 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 2751 BlockDriverAmendStatusCB *status_cb) 2752 { 2753 BDRVQcowState *s = bs->opaque; 2754 int old_version = s->qcow_version, new_version = old_version; 2755 uint64_t new_size = 0; 2756 const char *backing_file = NULL, *backing_format = NULL; 2757 bool lazy_refcounts = s->use_lazy_refcounts; 2758 const char *compat = NULL; 2759 uint64_t cluster_size = s->cluster_size; 2760 bool encrypt; 2761 int ret; 2762 QemuOptDesc *desc = opts->list->desc; 2763 2764 while (desc && desc->name) { 2765 if (!qemu_opt_find(opts, desc->name)) { 2766 /* only change explicitly defined options */ 2767 desc++; 2768 continue; 2769 } 2770 2771 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 2772 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 2773 if (!compat) { 2774 /* preserve default */ 2775 } else if (!strcmp(compat, "0.10")) { 2776 new_version = 2; 2777 } else if (!strcmp(compat, "1.1")) { 2778 new_version = 3; 2779 } else { 2780 fprintf(stderr, "Unknown compatibility level %s.\n", compat); 2781 return -EINVAL; 2782 } 2783 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 2784 fprintf(stderr, "Cannot change preallocation mode.\n"); 2785 return -ENOTSUP; 2786 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 2787 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 2788 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 2789 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 2790 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 2791 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 2792 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 2793 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 2794 !!s->cipher); 2795 2796 if (encrypt != !!s->cipher) { 2797 fprintf(stderr, "Changing the encryption flag is not " 2798 "supported.\n"); 2799 return -ENOTSUP; 2800 } 2801 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 2802 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 2803 cluster_size); 2804 if (cluster_size != s->cluster_size) { 2805 fprintf(stderr, "Changing the cluster size is not " 2806 "supported.\n"); 2807 return -ENOTSUP; 2808 } 2809 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 2810 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 2811 lazy_refcounts); 2812 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 2813 error_report("Cannot change refcount entry width"); 2814 return -ENOTSUP; 2815 } else { 2816 /* if this assertion fails, this probably means a new option was 2817 * added without having it covered here */ 2818 assert(false); 2819 } 2820 2821 desc++; 2822 } 2823 2824 if (new_version != old_version) { 2825 if (new_version > old_version) { 2826 /* Upgrade */ 2827 s->qcow_version = new_version; 2828 ret = qcow2_update_header(bs); 2829 if (ret < 0) { 2830 s->qcow_version = old_version; 2831 return ret; 2832 } 2833 } else { 2834 ret = qcow2_downgrade(bs, new_version, status_cb); 2835 if (ret < 0) { 2836 return ret; 2837 } 2838 } 2839 } 2840 2841 if (backing_file || backing_format) { 2842 ret = qcow2_change_backing_file(bs, 2843 backing_file ?: s->image_backing_file, 2844 backing_format ?: s->image_backing_format); 2845 if (ret < 0) { 2846 return ret; 2847 } 2848 } 2849 2850 if (s->use_lazy_refcounts != lazy_refcounts) { 2851 if (lazy_refcounts) { 2852 if (s->qcow_version < 3) { 2853 fprintf(stderr, "Lazy refcounts only supported with compatibility " 2854 "level 1.1 and above (use compat=1.1 or greater)\n"); 2855 return -EINVAL; 2856 } 2857 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 2858 ret = qcow2_update_header(bs); 2859 if (ret < 0) { 2860 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 2861 return ret; 2862 } 2863 s->use_lazy_refcounts = true; 2864 } else { 2865 /* make image clean first */ 2866 ret = qcow2_mark_clean(bs); 2867 if (ret < 0) { 2868 return ret; 2869 } 2870 /* now disallow lazy refcounts */ 2871 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 2872 ret = qcow2_update_header(bs); 2873 if (ret < 0) { 2874 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 2875 return ret; 2876 } 2877 s->use_lazy_refcounts = false; 2878 } 2879 } 2880 2881 if (new_size) { 2882 ret = bdrv_truncate(bs, new_size); 2883 if (ret < 0) { 2884 return ret; 2885 } 2886 } 2887 2888 return 0; 2889 } 2890 2891 /* 2892 * If offset or size are negative, respectively, they will not be included in 2893 * the BLOCK_IMAGE_CORRUPTED event emitted. 2894 * fatal will be ignored for read-only BDS; corruptions found there will always 2895 * be considered non-fatal. 2896 */ 2897 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 2898 int64_t size, const char *message_format, ...) 2899 { 2900 BDRVQcowState *s = bs->opaque; 2901 const char *node_name; 2902 char *message; 2903 va_list ap; 2904 2905 fatal = fatal && !bs->read_only; 2906 2907 if (s->signaled_corruption && 2908 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 2909 { 2910 return; 2911 } 2912 2913 va_start(ap, message_format); 2914 message = g_strdup_vprintf(message_format, ap); 2915 va_end(ap); 2916 2917 if (fatal) { 2918 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 2919 "corruption events will be suppressed\n", message); 2920 } else { 2921 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 2922 "corruption events will be suppressed\n", message); 2923 } 2924 2925 node_name = bdrv_get_node_name(bs); 2926 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 2927 *node_name != '\0', node_name, 2928 message, offset >= 0, offset, 2929 size >= 0, size, 2930 fatal, &error_abort); 2931 g_free(message); 2932 2933 if (fatal) { 2934 qcow2_mark_corrupt(bs); 2935 bs->drv = NULL; /* make BDS unusable */ 2936 } 2937 2938 s->signaled_corruption = true; 2939 } 2940 2941 static QemuOptsList qcow2_create_opts = { 2942 .name = "qcow2-create-opts", 2943 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 2944 .desc = { 2945 { 2946 .name = BLOCK_OPT_SIZE, 2947 .type = QEMU_OPT_SIZE, 2948 .help = "Virtual disk size" 2949 }, 2950 { 2951 .name = BLOCK_OPT_COMPAT_LEVEL, 2952 .type = QEMU_OPT_STRING, 2953 .help = "Compatibility level (0.10 or 1.1)" 2954 }, 2955 { 2956 .name = BLOCK_OPT_BACKING_FILE, 2957 .type = QEMU_OPT_STRING, 2958 .help = "File name of a base image" 2959 }, 2960 { 2961 .name = BLOCK_OPT_BACKING_FMT, 2962 .type = QEMU_OPT_STRING, 2963 .help = "Image format of the base image" 2964 }, 2965 { 2966 .name = BLOCK_OPT_ENCRYPT, 2967 .type = QEMU_OPT_BOOL, 2968 .help = "Encrypt the image", 2969 .def_value_str = "off" 2970 }, 2971 { 2972 .name = BLOCK_OPT_CLUSTER_SIZE, 2973 .type = QEMU_OPT_SIZE, 2974 .help = "qcow2 cluster size", 2975 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 2976 }, 2977 { 2978 .name = BLOCK_OPT_PREALLOC, 2979 .type = QEMU_OPT_STRING, 2980 .help = "Preallocation mode (allowed values: off, metadata, " 2981 "falloc, full)" 2982 }, 2983 { 2984 .name = BLOCK_OPT_LAZY_REFCOUNTS, 2985 .type = QEMU_OPT_BOOL, 2986 .help = "Postpone refcount updates", 2987 .def_value_str = "off" 2988 }, 2989 { 2990 .name = BLOCK_OPT_REFCOUNT_BITS, 2991 .type = QEMU_OPT_NUMBER, 2992 .help = "Width of a reference count entry in bits", 2993 .def_value_str = "16" 2994 }, 2995 { /* end of list */ } 2996 } 2997 }; 2998 2999 BlockDriver bdrv_qcow2 = { 3000 .format_name = "qcow2", 3001 .instance_size = sizeof(BDRVQcowState), 3002 .bdrv_probe = qcow2_probe, 3003 .bdrv_open = qcow2_open, 3004 .bdrv_close = qcow2_close, 3005 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3006 .bdrv_create = qcow2_create, 3007 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3008 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3009 .bdrv_set_key = qcow2_set_key, 3010 3011 .bdrv_co_readv = qcow2_co_readv, 3012 .bdrv_co_writev = qcow2_co_writev, 3013 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3014 3015 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3016 .bdrv_co_discard = qcow2_co_discard, 3017 .bdrv_truncate = qcow2_truncate, 3018 .bdrv_write_compressed = qcow2_write_compressed, 3019 .bdrv_make_empty = qcow2_make_empty, 3020 3021 .bdrv_snapshot_create = qcow2_snapshot_create, 3022 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3023 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3024 .bdrv_snapshot_list = qcow2_snapshot_list, 3025 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3026 .bdrv_get_info = qcow2_get_info, 3027 .bdrv_get_specific_info = qcow2_get_specific_info, 3028 3029 .bdrv_save_vmstate = qcow2_save_vmstate, 3030 .bdrv_load_vmstate = qcow2_load_vmstate, 3031 3032 .supports_backing = true, 3033 .bdrv_change_backing_file = qcow2_change_backing_file, 3034 3035 .bdrv_refresh_limits = qcow2_refresh_limits, 3036 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3037 3038 .create_opts = &qcow2_create_opts, 3039 .bdrv_check = qcow2_check, 3040 .bdrv_amend_options = qcow2_amend_options, 3041 3042 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3043 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3044 }; 3045 3046 static void bdrv_qcow2_init(void) 3047 { 3048 bdrv_register(&bdrv_qcow2); 3049 } 3050 3051 block_init(bdrv_qcow2_init); 3052