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 BDRVQcow2State *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->bs, 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->bs, 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->bs, 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->bs, 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 BDRVQcow2State *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 BDRVQcow2State *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->bs, offsetof(QCowHeader, incompatible_features), 264 &val, sizeof(val)); 265 if (ret < 0) { 266 return ret; 267 } 268 ret = bdrv_flush(bs->file->bs); 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 BDRVQcow2State *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 BDRVQcow2State *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 BDRVQcow2State *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 BDRVQcow2State *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 BDRVQcow2State *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 BDRVQcow2State *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 BDRVQcow2State *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 BDRVQcow2State *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 typedef struct Qcow2ReopenState { 593 Qcow2Cache *l2_table_cache; 594 Qcow2Cache *refcount_block_cache; 595 bool use_lazy_refcounts; 596 int overlap_check; 597 bool discard_passthrough[QCOW2_DISCARD_MAX]; 598 uint64_t cache_clean_interval; 599 } Qcow2ReopenState; 600 601 static int qcow2_update_options_prepare(BlockDriverState *bs, 602 Qcow2ReopenState *r, 603 QDict *options, int flags, 604 Error **errp) 605 { 606 BDRVQcow2State *s = bs->opaque; 607 QemuOpts *opts = NULL; 608 const char *opt_overlap_check, *opt_overlap_check_template; 609 int overlap_check_template = 0; 610 uint64_t l2_cache_size, refcount_cache_size; 611 int i; 612 Error *local_err = NULL; 613 int ret; 614 615 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 616 qemu_opts_absorb_qdict(opts, options, &local_err); 617 if (local_err) { 618 error_propagate(errp, local_err); 619 ret = -EINVAL; 620 goto fail; 621 } 622 623 /* get L2 table/refcount block cache size from command line options */ 624 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 625 &local_err); 626 if (local_err) { 627 error_propagate(errp, local_err); 628 ret = -EINVAL; 629 goto fail; 630 } 631 632 l2_cache_size /= s->cluster_size; 633 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 634 l2_cache_size = MIN_L2_CACHE_SIZE; 635 } 636 if (l2_cache_size > INT_MAX) { 637 error_setg(errp, "L2 cache size too big"); 638 ret = -EINVAL; 639 goto fail; 640 } 641 642 refcount_cache_size /= s->cluster_size; 643 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 644 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 645 } 646 if (refcount_cache_size > INT_MAX) { 647 error_setg(errp, "Refcount cache size too big"); 648 ret = -EINVAL; 649 goto fail; 650 } 651 652 /* alloc new L2 table/refcount block cache, flush old one */ 653 if (s->l2_table_cache) { 654 ret = qcow2_cache_flush(bs, s->l2_table_cache); 655 if (ret) { 656 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 657 goto fail; 658 } 659 } 660 661 if (s->refcount_block_cache) { 662 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 663 if (ret) { 664 error_setg_errno(errp, -ret, 665 "Failed to flush the refcount block cache"); 666 goto fail; 667 } 668 } 669 670 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 671 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 672 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 673 error_setg(errp, "Could not allocate metadata caches"); 674 ret = -ENOMEM; 675 goto fail; 676 } 677 678 /* New interval for cache cleanup timer */ 679 r->cache_clean_interval = 680 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 681 s->cache_clean_interval); 682 if (r->cache_clean_interval > UINT_MAX) { 683 error_setg(errp, "Cache clean interval too big"); 684 ret = -EINVAL; 685 goto fail; 686 } 687 688 /* lazy-refcounts; flush if going from enabled to disabled */ 689 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 690 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 691 if (r->use_lazy_refcounts && s->qcow_version < 3) { 692 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 693 "qemu 1.1 compatibility level"); 694 ret = -EINVAL; 695 goto fail; 696 } 697 698 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 699 ret = qcow2_mark_clean(bs); 700 if (ret < 0) { 701 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 702 goto fail; 703 } 704 } 705 706 /* Overlap check options */ 707 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 708 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 709 if (opt_overlap_check_template && opt_overlap_check && 710 strcmp(opt_overlap_check_template, opt_overlap_check)) 711 { 712 error_setg(errp, "Conflicting values for qcow2 options '" 713 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 714 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 715 ret = -EINVAL; 716 goto fail; 717 } 718 if (!opt_overlap_check) { 719 opt_overlap_check = opt_overlap_check_template ?: "cached"; 720 } 721 722 if (!strcmp(opt_overlap_check, "none")) { 723 overlap_check_template = 0; 724 } else if (!strcmp(opt_overlap_check, "constant")) { 725 overlap_check_template = QCOW2_OL_CONSTANT; 726 } else if (!strcmp(opt_overlap_check, "cached")) { 727 overlap_check_template = QCOW2_OL_CACHED; 728 } else if (!strcmp(opt_overlap_check, "all")) { 729 overlap_check_template = QCOW2_OL_ALL; 730 } else { 731 error_setg(errp, "Unsupported value '%s' for qcow2 option " 732 "'overlap-check'. Allowed are any of the following: " 733 "none, constant, cached, all", opt_overlap_check); 734 ret = -EINVAL; 735 goto fail; 736 } 737 738 r->overlap_check = 0; 739 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 740 /* overlap-check defines a template bitmask, but every flag may be 741 * overwritten through the associated boolean option */ 742 r->overlap_check |= 743 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 744 overlap_check_template & (1 << i)) << i; 745 } 746 747 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 748 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 749 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 750 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 751 flags & BDRV_O_UNMAP); 752 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 753 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 754 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 755 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 756 757 ret = 0; 758 fail: 759 qemu_opts_del(opts); 760 opts = NULL; 761 return ret; 762 } 763 764 static void qcow2_update_options_commit(BlockDriverState *bs, 765 Qcow2ReopenState *r) 766 { 767 BDRVQcow2State *s = bs->opaque; 768 int i; 769 770 if (s->l2_table_cache) { 771 qcow2_cache_destroy(bs, s->l2_table_cache); 772 } 773 if (s->refcount_block_cache) { 774 qcow2_cache_destroy(bs, s->refcount_block_cache); 775 } 776 s->l2_table_cache = r->l2_table_cache; 777 s->refcount_block_cache = r->refcount_block_cache; 778 779 s->overlap_check = r->overlap_check; 780 s->use_lazy_refcounts = r->use_lazy_refcounts; 781 782 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 783 s->discard_passthrough[i] = r->discard_passthrough[i]; 784 } 785 786 if (s->cache_clean_interval != r->cache_clean_interval) { 787 cache_clean_timer_del(bs); 788 s->cache_clean_interval = r->cache_clean_interval; 789 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 790 } 791 } 792 793 static void qcow2_update_options_abort(BlockDriverState *bs, 794 Qcow2ReopenState *r) 795 { 796 if (r->l2_table_cache) { 797 qcow2_cache_destroy(bs, r->l2_table_cache); 798 } 799 if (r->refcount_block_cache) { 800 qcow2_cache_destroy(bs, r->refcount_block_cache); 801 } 802 } 803 804 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 805 int flags, Error **errp) 806 { 807 Qcow2ReopenState r = {}; 808 int ret; 809 810 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 811 if (ret >= 0) { 812 qcow2_update_options_commit(bs, &r); 813 } else { 814 qcow2_update_options_abort(bs, &r); 815 } 816 817 return ret; 818 } 819 820 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 821 Error **errp) 822 { 823 BDRVQcow2State *s = bs->opaque; 824 unsigned int len, i; 825 int ret = 0; 826 QCowHeader header; 827 Error *local_err = NULL; 828 uint64_t ext_end; 829 uint64_t l1_vm_state_index; 830 831 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 832 if (ret < 0) { 833 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 834 goto fail; 835 } 836 be32_to_cpus(&header.magic); 837 be32_to_cpus(&header.version); 838 be64_to_cpus(&header.backing_file_offset); 839 be32_to_cpus(&header.backing_file_size); 840 be64_to_cpus(&header.size); 841 be32_to_cpus(&header.cluster_bits); 842 be32_to_cpus(&header.crypt_method); 843 be64_to_cpus(&header.l1_table_offset); 844 be32_to_cpus(&header.l1_size); 845 be64_to_cpus(&header.refcount_table_offset); 846 be32_to_cpus(&header.refcount_table_clusters); 847 be64_to_cpus(&header.snapshots_offset); 848 be32_to_cpus(&header.nb_snapshots); 849 850 if (header.magic != QCOW_MAGIC) { 851 error_setg(errp, "Image is not in qcow2 format"); 852 ret = -EINVAL; 853 goto fail; 854 } 855 if (header.version < 2 || header.version > 3) { 856 report_unsupported(bs, errp, "QCOW version %" PRIu32, header.version); 857 ret = -ENOTSUP; 858 goto fail; 859 } 860 861 s->qcow_version = header.version; 862 863 /* Initialise cluster size */ 864 if (header.cluster_bits < MIN_CLUSTER_BITS || 865 header.cluster_bits > MAX_CLUSTER_BITS) { 866 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 867 header.cluster_bits); 868 ret = -EINVAL; 869 goto fail; 870 } 871 872 s->cluster_bits = header.cluster_bits; 873 s->cluster_size = 1 << s->cluster_bits; 874 s->cluster_sectors = 1 << (s->cluster_bits - 9); 875 876 /* Initialise version 3 header fields */ 877 if (header.version == 2) { 878 header.incompatible_features = 0; 879 header.compatible_features = 0; 880 header.autoclear_features = 0; 881 header.refcount_order = 4; 882 header.header_length = 72; 883 } else { 884 be64_to_cpus(&header.incompatible_features); 885 be64_to_cpus(&header.compatible_features); 886 be64_to_cpus(&header.autoclear_features); 887 be32_to_cpus(&header.refcount_order); 888 be32_to_cpus(&header.header_length); 889 890 if (header.header_length < 104) { 891 error_setg(errp, "qcow2 header too short"); 892 ret = -EINVAL; 893 goto fail; 894 } 895 } 896 897 if (header.header_length > s->cluster_size) { 898 error_setg(errp, "qcow2 header exceeds cluster size"); 899 ret = -EINVAL; 900 goto fail; 901 } 902 903 if (header.header_length > sizeof(header)) { 904 s->unknown_header_fields_size = header.header_length - sizeof(header); 905 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 906 ret = bdrv_pread(bs->file->bs, sizeof(header), s->unknown_header_fields, 907 s->unknown_header_fields_size); 908 if (ret < 0) { 909 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 910 "fields"); 911 goto fail; 912 } 913 } 914 915 if (header.backing_file_offset > s->cluster_size) { 916 error_setg(errp, "Invalid backing file offset"); 917 ret = -EINVAL; 918 goto fail; 919 } 920 921 if (header.backing_file_offset) { 922 ext_end = header.backing_file_offset; 923 } else { 924 ext_end = 1 << header.cluster_bits; 925 } 926 927 /* Handle feature bits */ 928 s->incompatible_features = header.incompatible_features; 929 s->compatible_features = header.compatible_features; 930 s->autoclear_features = header.autoclear_features; 931 932 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 933 void *feature_table = NULL; 934 qcow2_read_extensions(bs, header.header_length, ext_end, 935 &feature_table, NULL); 936 report_unsupported_feature(bs, errp, feature_table, 937 s->incompatible_features & 938 ~QCOW2_INCOMPAT_MASK); 939 ret = -ENOTSUP; 940 g_free(feature_table); 941 goto fail; 942 } 943 944 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 945 /* Corrupt images may not be written to unless they are being repaired 946 */ 947 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 948 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 949 "read/write"); 950 ret = -EACCES; 951 goto fail; 952 } 953 } 954 955 /* Check support for various header values */ 956 if (header.refcount_order > 6) { 957 error_setg(errp, "Reference count entry width too large; may not " 958 "exceed 64 bits"); 959 ret = -EINVAL; 960 goto fail; 961 } 962 s->refcount_order = header.refcount_order; 963 s->refcount_bits = 1 << s->refcount_order; 964 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 965 s->refcount_max += s->refcount_max - 1; 966 967 if (header.crypt_method > QCOW_CRYPT_AES) { 968 error_setg(errp, "Unsupported encryption method: %" PRIu32, 969 header.crypt_method); 970 ret = -EINVAL; 971 goto fail; 972 } 973 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 974 error_setg(errp, "AES cipher not available"); 975 ret = -EINVAL; 976 goto fail; 977 } 978 s->crypt_method_header = header.crypt_method; 979 if (s->crypt_method_header) { 980 bs->encrypted = 1; 981 } 982 983 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 984 s->l2_size = 1 << s->l2_bits; 985 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 986 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 987 s->refcount_block_size = 1 << s->refcount_block_bits; 988 bs->total_sectors = header.size / 512; 989 s->csize_shift = (62 - (s->cluster_bits - 8)); 990 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 991 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 992 993 s->refcount_table_offset = header.refcount_table_offset; 994 s->refcount_table_size = 995 header.refcount_table_clusters << (s->cluster_bits - 3); 996 997 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 998 error_setg(errp, "Reference count table too large"); 999 ret = -EINVAL; 1000 goto fail; 1001 } 1002 1003 ret = validate_table_offset(bs, s->refcount_table_offset, 1004 s->refcount_table_size, sizeof(uint64_t)); 1005 if (ret < 0) { 1006 error_setg(errp, "Invalid reference count table offset"); 1007 goto fail; 1008 } 1009 1010 /* Snapshot table offset/length */ 1011 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1012 error_setg(errp, "Too many snapshots"); 1013 ret = -EINVAL; 1014 goto fail; 1015 } 1016 1017 ret = validate_table_offset(bs, header.snapshots_offset, 1018 header.nb_snapshots, 1019 sizeof(QCowSnapshotHeader)); 1020 if (ret < 0) { 1021 error_setg(errp, "Invalid snapshot table offset"); 1022 goto fail; 1023 } 1024 1025 /* read the level 1 table */ 1026 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1027 error_setg(errp, "Active L1 table too large"); 1028 ret = -EFBIG; 1029 goto fail; 1030 } 1031 s->l1_size = header.l1_size; 1032 1033 l1_vm_state_index = size_to_l1(s, header.size); 1034 if (l1_vm_state_index > INT_MAX) { 1035 error_setg(errp, "Image is too big"); 1036 ret = -EFBIG; 1037 goto fail; 1038 } 1039 s->l1_vm_state_index = l1_vm_state_index; 1040 1041 /* the L1 table must contain at least enough entries to put 1042 header.size bytes */ 1043 if (s->l1_size < s->l1_vm_state_index) { 1044 error_setg(errp, "L1 table is too small"); 1045 ret = -EINVAL; 1046 goto fail; 1047 } 1048 1049 ret = validate_table_offset(bs, header.l1_table_offset, 1050 header.l1_size, sizeof(uint64_t)); 1051 if (ret < 0) { 1052 error_setg(errp, "Invalid L1 table offset"); 1053 goto fail; 1054 } 1055 s->l1_table_offset = header.l1_table_offset; 1056 1057 1058 if (s->l1_size > 0) { 1059 s->l1_table = qemu_try_blockalign(bs->file->bs, 1060 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1061 if (s->l1_table == NULL) { 1062 error_setg(errp, "Could not allocate L1 table"); 1063 ret = -ENOMEM; 1064 goto fail; 1065 } 1066 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 1067 s->l1_size * sizeof(uint64_t)); 1068 if (ret < 0) { 1069 error_setg_errno(errp, -ret, "Could not read L1 table"); 1070 goto fail; 1071 } 1072 for(i = 0;i < s->l1_size; i++) { 1073 be64_to_cpus(&s->l1_table[i]); 1074 } 1075 } 1076 1077 /* Parse driver-specific options */ 1078 ret = qcow2_update_options(bs, options, flags, errp); 1079 if (ret < 0) { 1080 goto fail; 1081 } 1082 1083 s->cluster_cache = g_malloc(s->cluster_size); 1084 /* one more sector for decompressed data alignment */ 1085 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1086 * s->cluster_size + 512); 1087 if (s->cluster_data == NULL) { 1088 error_setg(errp, "Could not allocate temporary cluster buffer"); 1089 ret = -ENOMEM; 1090 goto fail; 1091 } 1092 1093 s->cluster_cache_offset = -1; 1094 s->flags = flags; 1095 1096 ret = qcow2_refcount_init(bs); 1097 if (ret != 0) { 1098 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1099 goto fail; 1100 } 1101 1102 QLIST_INIT(&s->cluster_allocs); 1103 QTAILQ_INIT(&s->discards); 1104 1105 /* read qcow2 extensions */ 1106 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1107 &local_err)) { 1108 error_propagate(errp, local_err); 1109 ret = -EINVAL; 1110 goto fail; 1111 } 1112 1113 /* read the backing file name */ 1114 if (header.backing_file_offset != 0) { 1115 len = header.backing_file_size; 1116 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1117 len >= sizeof(bs->backing_file)) { 1118 error_setg(errp, "Backing file name too long"); 1119 ret = -EINVAL; 1120 goto fail; 1121 } 1122 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 1123 bs->backing_file, len); 1124 if (ret < 0) { 1125 error_setg_errno(errp, -ret, "Could not read backing file name"); 1126 goto fail; 1127 } 1128 bs->backing_file[len] = '\0'; 1129 s->image_backing_file = g_strdup(bs->backing_file); 1130 } 1131 1132 /* Internal snapshots */ 1133 s->snapshots_offset = header.snapshots_offset; 1134 s->nb_snapshots = header.nb_snapshots; 1135 1136 ret = qcow2_read_snapshots(bs); 1137 if (ret < 0) { 1138 error_setg_errno(errp, -ret, "Could not read snapshots"); 1139 goto fail; 1140 } 1141 1142 /* Clear unknown autoclear feature bits */ 1143 if (!bs->read_only && !(flags & BDRV_O_INCOMING) && s->autoclear_features) { 1144 s->autoclear_features = 0; 1145 ret = qcow2_update_header(bs); 1146 if (ret < 0) { 1147 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1148 goto fail; 1149 } 1150 } 1151 1152 /* Initialise locks */ 1153 qemu_co_mutex_init(&s->lock); 1154 1155 /* Repair image if dirty */ 1156 if (!(flags & (BDRV_O_CHECK | BDRV_O_INCOMING)) && !bs->read_only && 1157 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1158 BdrvCheckResult result = {0}; 1159 1160 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1161 if (ret < 0) { 1162 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1163 goto fail; 1164 } 1165 } 1166 1167 #ifdef DEBUG_ALLOC 1168 { 1169 BdrvCheckResult result = {0}; 1170 qcow2_check_refcounts(bs, &result, 0); 1171 } 1172 #endif 1173 return ret; 1174 1175 fail: 1176 g_free(s->unknown_header_fields); 1177 cleanup_unknown_header_ext(bs); 1178 qcow2_free_snapshots(bs); 1179 qcow2_refcount_close(bs); 1180 qemu_vfree(s->l1_table); 1181 /* else pre-write overlap checks in cache_destroy may crash */ 1182 s->l1_table = NULL; 1183 cache_clean_timer_del(bs); 1184 if (s->l2_table_cache) { 1185 qcow2_cache_destroy(bs, s->l2_table_cache); 1186 } 1187 if (s->refcount_block_cache) { 1188 qcow2_cache_destroy(bs, s->refcount_block_cache); 1189 } 1190 g_free(s->cluster_cache); 1191 qemu_vfree(s->cluster_data); 1192 return ret; 1193 } 1194 1195 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1196 { 1197 BDRVQcow2State *s = bs->opaque; 1198 1199 bs->bl.write_zeroes_alignment = s->cluster_sectors; 1200 } 1201 1202 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1203 { 1204 BDRVQcow2State *s = bs->opaque; 1205 uint8_t keybuf[16]; 1206 int len, i; 1207 Error *err = NULL; 1208 1209 memset(keybuf, 0, 16); 1210 len = strlen(key); 1211 if (len > 16) 1212 len = 16; 1213 /* XXX: we could compress the chars to 7 bits to increase 1214 entropy */ 1215 for(i = 0;i < len;i++) { 1216 keybuf[i] = key[i]; 1217 } 1218 assert(bs->encrypted); 1219 1220 qcrypto_cipher_free(s->cipher); 1221 s->cipher = qcrypto_cipher_new( 1222 QCRYPTO_CIPHER_ALG_AES_128, 1223 QCRYPTO_CIPHER_MODE_CBC, 1224 keybuf, G_N_ELEMENTS(keybuf), 1225 &err); 1226 1227 if (!s->cipher) { 1228 /* XXX would be nice if errors in this method could 1229 * be properly propagate to the caller. Would need 1230 * the bdrv_set_key() API signature to be fixed. */ 1231 error_free(err); 1232 return -1; 1233 } 1234 return 0; 1235 } 1236 1237 static int qcow2_reopen_prepare(BDRVReopenState *state, 1238 BlockReopenQueue *queue, Error **errp) 1239 { 1240 Qcow2ReopenState *r; 1241 int ret; 1242 1243 r = g_new0(Qcow2ReopenState, 1); 1244 state->opaque = r; 1245 1246 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1247 state->flags, errp); 1248 if (ret < 0) { 1249 goto fail; 1250 } 1251 1252 /* We need to write out any unwritten data if we reopen read-only. */ 1253 if ((state->flags & BDRV_O_RDWR) == 0) { 1254 ret = bdrv_flush(state->bs); 1255 if (ret < 0) { 1256 goto fail; 1257 } 1258 1259 ret = qcow2_mark_clean(state->bs); 1260 if (ret < 0) { 1261 goto fail; 1262 } 1263 } 1264 1265 return 0; 1266 1267 fail: 1268 qcow2_update_options_abort(state->bs, r); 1269 g_free(r); 1270 return ret; 1271 } 1272 1273 static void qcow2_reopen_commit(BDRVReopenState *state) 1274 { 1275 qcow2_update_options_commit(state->bs, state->opaque); 1276 g_free(state->opaque); 1277 } 1278 1279 static void qcow2_reopen_abort(BDRVReopenState *state) 1280 { 1281 qcow2_update_options_abort(state->bs, state->opaque); 1282 g_free(state->opaque); 1283 } 1284 1285 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1286 int64_t sector_num, int nb_sectors, int *pnum) 1287 { 1288 BDRVQcow2State *s = bs->opaque; 1289 uint64_t cluster_offset; 1290 int index_in_cluster, ret; 1291 int64_t status = 0; 1292 1293 *pnum = nb_sectors; 1294 qemu_co_mutex_lock(&s->lock); 1295 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); 1296 qemu_co_mutex_unlock(&s->lock); 1297 if (ret < 0) { 1298 return ret; 1299 } 1300 1301 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1302 !s->cipher) { 1303 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1304 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1305 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1306 } 1307 if (ret == QCOW2_CLUSTER_ZERO) { 1308 status |= BDRV_BLOCK_ZERO; 1309 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1310 status |= BDRV_BLOCK_DATA; 1311 } 1312 return status; 1313 } 1314 1315 /* handle reading after the end of the backing file */ 1316 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1317 int64_t sector_num, int nb_sectors) 1318 { 1319 int n1; 1320 if ((sector_num + nb_sectors) <= bs->total_sectors) 1321 return nb_sectors; 1322 if (sector_num >= bs->total_sectors) 1323 n1 = 0; 1324 else 1325 n1 = bs->total_sectors - sector_num; 1326 1327 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1328 1329 return n1; 1330 } 1331 1332 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1333 int remaining_sectors, QEMUIOVector *qiov) 1334 { 1335 BDRVQcow2State *s = bs->opaque; 1336 int index_in_cluster, n1; 1337 int ret; 1338 int cur_nr_sectors; /* number of sectors in current iteration */ 1339 uint64_t cluster_offset = 0; 1340 uint64_t bytes_done = 0; 1341 QEMUIOVector hd_qiov; 1342 uint8_t *cluster_data = NULL; 1343 1344 qemu_iovec_init(&hd_qiov, qiov->niov); 1345 1346 qemu_co_mutex_lock(&s->lock); 1347 1348 while (remaining_sectors != 0) { 1349 1350 /* prepare next request */ 1351 cur_nr_sectors = remaining_sectors; 1352 if (s->cipher) { 1353 cur_nr_sectors = MIN(cur_nr_sectors, 1354 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1355 } 1356 1357 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1358 &cur_nr_sectors, &cluster_offset); 1359 if (ret < 0) { 1360 goto fail; 1361 } 1362 1363 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1364 1365 qemu_iovec_reset(&hd_qiov); 1366 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1367 cur_nr_sectors * 512); 1368 1369 switch (ret) { 1370 case QCOW2_CLUSTER_UNALLOCATED: 1371 1372 if (bs->backing) { 1373 /* read from the base image */ 1374 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1375 sector_num, cur_nr_sectors); 1376 if (n1 > 0) { 1377 QEMUIOVector local_qiov; 1378 1379 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1380 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1381 n1 * BDRV_SECTOR_SIZE); 1382 1383 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1384 qemu_co_mutex_unlock(&s->lock); 1385 ret = bdrv_co_readv(bs->backing->bs, sector_num, 1386 n1, &local_qiov); 1387 qemu_co_mutex_lock(&s->lock); 1388 1389 qemu_iovec_destroy(&local_qiov); 1390 1391 if (ret < 0) { 1392 goto fail; 1393 } 1394 } 1395 } else { 1396 /* Note: in this case, no need to wait */ 1397 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1398 } 1399 break; 1400 1401 case QCOW2_CLUSTER_ZERO: 1402 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1403 break; 1404 1405 case QCOW2_CLUSTER_COMPRESSED: 1406 /* add AIO support for compressed blocks ? */ 1407 ret = qcow2_decompress_cluster(bs, cluster_offset); 1408 if (ret < 0) { 1409 goto fail; 1410 } 1411 1412 qemu_iovec_from_buf(&hd_qiov, 0, 1413 s->cluster_cache + index_in_cluster * 512, 1414 512 * cur_nr_sectors); 1415 break; 1416 1417 case QCOW2_CLUSTER_NORMAL: 1418 if ((cluster_offset & 511) != 0) { 1419 ret = -EIO; 1420 goto fail; 1421 } 1422 1423 if (bs->encrypted) { 1424 assert(s->cipher); 1425 1426 /* 1427 * For encrypted images, read everything into a temporary 1428 * contiguous buffer on which the AES functions can work. 1429 */ 1430 if (!cluster_data) { 1431 cluster_data = 1432 qemu_try_blockalign(bs->file->bs, 1433 QCOW_MAX_CRYPT_CLUSTERS 1434 * s->cluster_size); 1435 if (cluster_data == NULL) { 1436 ret = -ENOMEM; 1437 goto fail; 1438 } 1439 } 1440 1441 assert(cur_nr_sectors <= 1442 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1443 qemu_iovec_reset(&hd_qiov); 1444 qemu_iovec_add(&hd_qiov, cluster_data, 1445 512 * cur_nr_sectors); 1446 } 1447 1448 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1449 qemu_co_mutex_unlock(&s->lock); 1450 ret = bdrv_co_readv(bs->file->bs, 1451 (cluster_offset >> 9) + index_in_cluster, 1452 cur_nr_sectors, &hd_qiov); 1453 qemu_co_mutex_lock(&s->lock); 1454 if (ret < 0) { 1455 goto fail; 1456 } 1457 if (bs->encrypted) { 1458 assert(s->cipher); 1459 Error *err = NULL; 1460 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1461 cluster_data, cur_nr_sectors, false, 1462 &err) < 0) { 1463 error_free(err); 1464 ret = -EIO; 1465 goto fail; 1466 } 1467 qemu_iovec_from_buf(qiov, bytes_done, 1468 cluster_data, 512 * cur_nr_sectors); 1469 } 1470 break; 1471 1472 default: 1473 g_assert_not_reached(); 1474 ret = -EIO; 1475 goto fail; 1476 } 1477 1478 remaining_sectors -= cur_nr_sectors; 1479 sector_num += cur_nr_sectors; 1480 bytes_done += cur_nr_sectors * 512; 1481 } 1482 ret = 0; 1483 1484 fail: 1485 qemu_co_mutex_unlock(&s->lock); 1486 1487 qemu_iovec_destroy(&hd_qiov); 1488 qemu_vfree(cluster_data); 1489 1490 return ret; 1491 } 1492 1493 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1494 int64_t sector_num, 1495 int remaining_sectors, 1496 QEMUIOVector *qiov) 1497 { 1498 BDRVQcow2State *s = bs->opaque; 1499 int index_in_cluster; 1500 int ret; 1501 int cur_nr_sectors; /* number of sectors in current iteration */ 1502 uint64_t cluster_offset; 1503 QEMUIOVector hd_qiov; 1504 uint64_t bytes_done = 0; 1505 uint8_t *cluster_data = NULL; 1506 QCowL2Meta *l2meta = NULL; 1507 1508 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1509 remaining_sectors); 1510 1511 qemu_iovec_init(&hd_qiov, qiov->niov); 1512 1513 s->cluster_cache_offset = -1; /* disable compressed cache */ 1514 1515 qemu_co_mutex_lock(&s->lock); 1516 1517 while (remaining_sectors != 0) { 1518 1519 l2meta = NULL; 1520 1521 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1522 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1523 cur_nr_sectors = remaining_sectors; 1524 if (bs->encrypted && 1525 cur_nr_sectors > 1526 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1527 cur_nr_sectors = 1528 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1529 } 1530 1531 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1532 &cur_nr_sectors, &cluster_offset, &l2meta); 1533 if (ret < 0) { 1534 goto fail; 1535 } 1536 1537 assert((cluster_offset & 511) == 0); 1538 1539 qemu_iovec_reset(&hd_qiov); 1540 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1541 cur_nr_sectors * 512); 1542 1543 if (bs->encrypted) { 1544 Error *err = NULL; 1545 assert(s->cipher); 1546 if (!cluster_data) { 1547 cluster_data = qemu_try_blockalign(bs->file->bs, 1548 QCOW_MAX_CRYPT_CLUSTERS 1549 * s->cluster_size); 1550 if (cluster_data == NULL) { 1551 ret = -ENOMEM; 1552 goto fail; 1553 } 1554 } 1555 1556 assert(hd_qiov.size <= 1557 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1558 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1559 1560 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1561 cluster_data, cur_nr_sectors, 1562 true, &err) < 0) { 1563 error_free(err); 1564 ret = -EIO; 1565 goto fail; 1566 } 1567 1568 qemu_iovec_reset(&hd_qiov); 1569 qemu_iovec_add(&hd_qiov, cluster_data, 1570 cur_nr_sectors * 512); 1571 } 1572 1573 ret = qcow2_pre_write_overlap_check(bs, 0, 1574 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1575 cur_nr_sectors * BDRV_SECTOR_SIZE); 1576 if (ret < 0) { 1577 goto fail; 1578 } 1579 1580 qemu_co_mutex_unlock(&s->lock); 1581 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1582 trace_qcow2_writev_data(qemu_coroutine_self(), 1583 (cluster_offset >> 9) + index_in_cluster); 1584 ret = bdrv_co_writev(bs->file->bs, 1585 (cluster_offset >> 9) + index_in_cluster, 1586 cur_nr_sectors, &hd_qiov); 1587 qemu_co_mutex_lock(&s->lock); 1588 if (ret < 0) { 1589 goto fail; 1590 } 1591 1592 while (l2meta != NULL) { 1593 QCowL2Meta *next; 1594 1595 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1596 if (ret < 0) { 1597 goto fail; 1598 } 1599 1600 /* Take the request off the list of running requests */ 1601 if (l2meta->nb_clusters != 0) { 1602 QLIST_REMOVE(l2meta, next_in_flight); 1603 } 1604 1605 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1606 1607 next = l2meta->next; 1608 g_free(l2meta); 1609 l2meta = next; 1610 } 1611 1612 remaining_sectors -= cur_nr_sectors; 1613 sector_num += cur_nr_sectors; 1614 bytes_done += cur_nr_sectors * 512; 1615 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1616 } 1617 ret = 0; 1618 1619 fail: 1620 qemu_co_mutex_unlock(&s->lock); 1621 1622 while (l2meta != NULL) { 1623 QCowL2Meta *next; 1624 1625 if (l2meta->nb_clusters != 0) { 1626 QLIST_REMOVE(l2meta, next_in_flight); 1627 } 1628 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1629 1630 next = l2meta->next; 1631 g_free(l2meta); 1632 l2meta = next; 1633 } 1634 1635 qemu_iovec_destroy(&hd_qiov); 1636 qemu_vfree(cluster_data); 1637 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1638 1639 return ret; 1640 } 1641 1642 static void qcow2_close(BlockDriverState *bs) 1643 { 1644 BDRVQcow2State *s = bs->opaque; 1645 qemu_vfree(s->l1_table); 1646 /* else pre-write overlap checks in cache_destroy may crash */ 1647 s->l1_table = NULL; 1648 1649 if (!(bs->open_flags & BDRV_O_INCOMING)) { 1650 int ret1, ret2; 1651 1652 ret1 = qcow2_cache_flush(bs, s->l2_table_cache); 1653 ret2 = qcow2_cache_flush(bs, s->refcount_block_cache); 1654 1655 if (ret1) { 1656 error_report("Failed to flush the L2 table cache: %s", 1657 strerror(-ret1)); 1658 } 1659 if (ret2) { 1660 error_report("Failed to flush the refcount block cache: %s", 1661 strerror(-ret2)); 1662 } 1663 1664 if (!ret1 && !ret2) { 1665 qcow2_mark_clean(bs); 1666 } 1667 } 1668 1669 cache_clean_timer_del(bs); 1670 qcow2_cache_destroy(bs, s->l2_table_cache); 1671 qcow2_cache_destroy(bs, s->refcount_block_cache); 1672 1673 qcrypto_cipher_free(s->cipher); 1674 s->cipher = NULL; 1675 1676 g_free(s->unknown_header_fields); 1677 cleanup_unknown_header_ext(bs); 1678 1679 g_free(s->image_backing_file); 1680 g_free(s->image_backing_format); 1681 1682 g_free(s->cluster_cache); 1683 qemu_vfree(s->cluster_data); 1684 qcow2_refcount_close(bs); 1685 qcow2_free_snapshots(bs); 1686 } 1687 1688 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1689 { 1690 BDRVQcow2State *s = bs->opaque; 1691 int flags = s->flags; 1692 QCryptoCipher *cipher = NULL; 1693 QDict *options; 1694 Error *local_err = NULL; 1695 int ret; 1696 1697 /* 1698 * Backing files are read-only which makes all of their metadata immutable, 1699 * that means we don't have to worry about reopening them here. 1700 */ 1701 1702 cipher = s->cipher; 1703 s->cipher = NULL; 1704 1705 qcow2_close(bs); 1706 1707 bdrv_invalidate_cache(bs->file->bs, &local_err); 1708 if (local_err) { 1709 error_propagate(errp, local_err); 1710 return; 1711 } 1712 1713 memset(s, 0, sizeof(BDRVQcow2State)); 1714 options = qdict_clone_shallow(bs->options); 1715 1716 ret = qcow2_open(bs, options, flags, &local_err); 1717 QDECREF(options); 1718 if (local_err) { 1719 error_setg(errp, "Could not reopen qcow2 layer: %s", 1720 error_get_pretty(local_err)); 1721 error_free(local_err); 1722 return; 1723 } else if (ret < 0) { 1724 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1725 return; 1726 } 1727 1728 s->cipher = cipher; 1729 } 1730 1731 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1732 size_t len, size_t buflen) 1733 { 1734 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1735 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1736 1737 if (buflen < ext_len) { 1738 return -ENOSPC; 1739 } 1740 1741 *ext_backing_fmt = (QCowExtension) { 1742 .magic = cpu_to_be32(magic), 1743 .len = cpu_to_be32(len), 1744 }; 1745 memcpy(buf + sizeof(QCowExtension), s, len); 1746 1747 return ext_len; 1748 } 1749 1750 /* 1751 * Updates the qcow2 header, including the variable length parts of it, i.e. 1752 * the backing file name and all extensions. qcow2 was not designed to allow 1753 * such changes, so if we run out of space (we can only use the first cluster) 1754 * this function may fail. 1755 * 1756 * Returns 0 on success, -errno in error cases. 1757 */ 1758 int qcow2_update_header(BlockDriverState *bs) 1759 { 1760 BDRVQcow2State *s = bs->opaque; 1761 QCowHeader *header; 1762 char *buf; 1763 size_t buflen = s->cluster_size; 1764 int ret; 1765 uint64_t total_size; 1766 uint32_t refcount_table_clusters; 1767 size_t header_length; 1768 Qcow2UnknownHeaderExtension *uext; 1769 1770 buf = qemu_blockalign(bs, buflen); 1771 1772 /* Header structure */ 1773 header = (QCowHeader*) buf; 1774 1775 if (buflen < sizeof(*header)) { 1776 ret = -ENOSPC; 1777 goto fail; 1778 } 1779 1780 header_length = sizeof(*header) + s->unknown_header_fields_size; 1781 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1782 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1783 1784 *header = (QCowHeader) { 1785 /* Version 2 fields */ 1786 .magic = cpu_to_be32(QCOW_MAGIC), 1787 .version = cpu_to_be32(s->qcow_version), 1788 .backing_file_offset = 0, 1789 .backing_file_size = 0, 1790 .cluster_bits = cpu_to_be32(s->cluster_bits), 1791 .size = cpu_to_be64(total_size), 1792 .crypt_method = cpu_to_be32(s->crypt_method_header), 1793 .l1_size = cpu_to_be32(s->l1_size), 1794 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1795 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1796 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1797 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1798 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1799 1800 /* Version 3 fields */ 1801 .incompatible_features = cpu_to_be64(s->incompatible_features), 1802 .compatible_features = cpu_to_be64(s->compatible_features), 1803 .autoclear_features = cpu_to_be64(s->autoclear_features), 1804 .refcount_order = cpu_to_be32(s->refcount_order), 1805 .header_length = cpu_to_be32(header_length), 1806 }; 1807 1808 /* For older versions, write a shorter header */ 1809 switch (s->qcow_version) { 1810 case 2: 1811 ret = offsetof(QCowHeader, incompatible_features); 1812 break; 1813 case 3: 1814 ret = sizeof(*header); 1815 break; 1816 default: 1817 ret = -EINVAL; 1818 goto fail; 1819 } 1820 1821 buf += ret; 1822 buflen -= ret; 1823 memset(buf, 0, buflen); 1824 1825 /* Preserve any unknown field in the header */ 1826 if (s->unknown_header_fields_size) { 1827 if (buflen < s->unknown_header_fields_size) { 1828 ret = -ENOSPC; 1829 goto fail; 1830 } 1831 1832 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1833 buf += s->unknown_header_fields_size; 1834 buflen -= s->unknown_header_fields_size; 1835 } 1836 1837 /* Backing file format header extension */ 1838 if (s->image_backing_format) { 1839 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1840 s->image_backing_format, 1841 strlen(s->image_backing_format), 1842 buflen); 1843 if (ret < 0) { 1844 goto fail; 1845 } 1846 1847 buf += ret; 1848 buflen -= ret; 1849 } 1850 1851 /* Feature table */ 1852 Qcow2Feature features[] = { 1853 { 1854 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1855 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1856 .name = "dirty bit", 1857 }, 1858 { 1859 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1860 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1861 .name = "corrupt bit", 1862 }, 1863 { 1864 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1865 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1866 .name = "lazy refcounts", 1867 }, 1868 }; 1869 1870 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1871 features, sizeof(features), buflen); 1872 if (ret < 0) { 1873 goto fail; 1874 } 1875 buf += ret; 1876 buflen -= ret; 1877 1878 /* Keep unknown header extensions */ 1879 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1880 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1881 if (ret < 0) { 1882 goto fail; 1883 } 1884 1885 buf += ret; 1886 buflen -= ret; 1887 } 1888 1889 /* End of header extensions */ 1890 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1891 if (ret < 0) { 1892 goto fail; 1893 } 1894 1895 buf += ret; 1896 buflen -= ret; 1897 1898 /* Backing file name */ 1899 if (s->image_backing_file) { 1900 size_t backing_file_len = strlen(s->image_backing_file); 1901 1902 if (buflen < backing_file_len) { 1903 ret = -ENOSPC; 1904 goto fail; 1905 } 1906 1907 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1908 strncpy(buf, s->image_backing_file, buflen); 1909 1910 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1911 header->backing_file_size = cpu_to_be32(backing_file_len); 1912 } 1913 1914 /* Write the new header */ 1915 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size); 1916 if (ret < 0) { 1917 goto fail; 1918 } 1919 1920 ret = 0; 1921 fail: 1922 qemu_vfree(header); 1923 return ret; 1924 } 1925 1926 static int qcow2_change_backing_file(BlockDriverState *bs, 1927 const char *backing_file, const char *backing_fmt) 1928 { 1929 BDRVQcow2State *s = bs->opaque; 1930 1931 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1932 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1933 1934 g_free(s->image_backing_file); 1935 g_free(s->image_backing_format); 1936 1937 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 1938 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 1939 1940 return qcow2_update_header(bs); 1941 } 1942 1943 static int preallocate(BlockDriverState *bs) 1944 { 1945 uint64_t nb_sectors; 1946 uint64_t offset; 1947 uint64_t host_offset = 0; 1948 int num; 1949 int ret; 1950 QCowL2Meta *meta; 1951 1952 nb_sectors = bdrv_nb_sectors(bs); 1953 offset = 0; 1954 1955 while (nb_sectors) { 1956 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 1957 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 1958 &host_offset, &meta); 1959 if (ret < 0) { 1960 return ret; 1961 } 1962 1963 while (meta) { 1964 QCowL2Meta *next = meta->next; 1965 1966 ret = qcow2_alloc_cluster_link_l2(bs, meta); 1967 if (ret < 0) { 1968 qcow2_free_any_clusters(bs, meta->alloc_offset, 1969 meta->nb_clusters, QCOW2_DISCARD_NEVER); 1970 return ret; 1971 } 1972 1973 /* There are no dependent requests, but we need to remove our 1974 * request from the list of in-flight requests */ 1975 QLIST_REMOVE(meta, next_in_flight); 1976 1977 g_free(meta); 1978 meta = next; 1979 } 1980 1981 /* TODO Preallocate data if requested */ 1982 1983 nb_sectors -= num; 1984 offset += num << BDRV_SECTOR_BITS; 1985 } 1986 1987 /* 1988 * It is expected that the image file is large enough to actually contain 1989 * all of the allocated clusters (otherwise we get failing reads after 1990 * EOF). Extend the image to the last allocated sector. 1991 */ 1992 if (host_offset != 0) { 1993 uint8_t buf[BDRV_SECTOR_SIZE]; 1994 memset(buf, 0, BDRV_SECTOR_SIZE); 1995 ret = bdrv_write(bs->file->bs, 1996 (host_offset >> BDRV_SECTOR_BITS) + num - 1, 1997 buf, 1); 1998 if (ret < 0) { 1999 return ret; 2000 } 2001 } 2002 2003 return 0; 2004 } 2005 2006 static int qcow2_create2(const char *filename, int64_t total_size, 2007 const char *backing_file, const char *backing_format, 2008 int flags, size_t cluster_size, PreallocMode prealloc, 2009 QemuOpts *opts, int version, int refcount_order, 2010 Error **errp) 2011 { 2012 int cluster_bits; 2013 QDict *options; 2014 2015 /* Calculate cluster_bits */ 2016 cluster_bits = ctz32(cluster_size); 2017 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2018 (1 << cluster_bits) != cluster_size) 2019 { 2020 error_setg(errp, "Cluster size must be a power of two between %d and " 2021 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2022 return -EINVAL; 2023 } 2024 2025 /* 2026 * Open the image file and write a minimal qcow2 header. 2027 * 2028 * We keep things simple and start with a zero-sized image. We also 2029 * do without refcount blocks or a L1 table for now. We'll fix the 2030 * inconsistency later. 2031 * 2032 * We do need a refcount table because growing the refcount table means 2033 * allocating two new refcount blocks - the seconds of which would be at 2034 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2035 * size for any qcow2 image. 2036 */ 2037 BlockDriverState* bs; 2038 QCowHeader *header; 2039 uint64_t* refcount_table; 2040 Error *local_err = NULL; 2041 int ret; 2042 2043 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2044 /* Note: The following calculation does not need to be exact; if it is a 2045 * bit off, either some bytes will be "leaked" (which is fine) or we 2046 * will need to increase the file size by some bytes (which is fine, 2047 * too, as long as the bulk is allocated here). Therefore, using 2048 * floating point arithmetic is fine. */ 2049 int64_t meta_size = 0; 2050 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2051 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2052 int refblock_bits, refblock_size; 2053 /* refcount entry size in bytes */ 2054 double rces = (1 << refcount_order) / 8.; 2055 2056 /* see qcow2_open() */ 2057 refblock_bits = cluster_bits - (refcount_order - 3); 2058 refblock_size = 1 << refblock_bits; 2059 2060 /* header: 1 cluster */ 2061 meta_size += cluster_size; 2062 2063 /* total size of L2 tables */ 2064 nl2e = aligned_total_size / cluster_size; 2065 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2066 meta_size += nl2e * sizeof(uint64_t); 2067 2068 /* total size of L1 tables */ 2069 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2070 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2071 meta_size += nl1e * sizeof(uint64_t); 2072 2073 /* total size of refcount blocks 2074 * 2075 * note: every host cluster is reference-counted, including metadata 2076 * (even refcount blocks are recursively included). 2077 * Let: 2078 * a = total_size (this is the guest disk size) 2079 * m = meta size not including refcount blocks and refcount tables 2080 * c = cluster size 2081 * y1 = number of refcount blocks entries 2082 * y2 = meta size including everything 2083 * rces = refcount entry size in bytes 2084 * then, 2085 * y1 = (y2 + a)/c 2086 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2087 * we can get y1: 2088 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2089 */ 2090 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2091 / (cluster_size - rces - rces * sizeof(uint64_t) 2092 / cluster_size); 2093 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2094 2095 /* total size of refcount tables */ 2096 nreftablee = nrefblocke / refblock_size; 2097 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2098 meta_size += nreftablee * sizeof(uint64_t); 2099 2100 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2101 aligned_total_size + meta_size, &error_abort); 2102 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2103 &error_abort); 2104 } 2105 2106 ret = bdrv_create_file(filename, opts, &local_err); 2107 if (ret < 0) { 2108 error_propagate(errp, local_err); 2109 return ret; 2110 } 2111 2112 bs = NULL; 2113 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 2114 &local_err); 2115 if (ret < 0) { 2116 error_propagate(errp, local_err); 2117 return ret; 2118 } 2119 2120 /* Write the header */ 2121 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2122 header = g_malloc0(cluster_size); 2123 *header = (QCowHeader) { 2124 .magic = cpu_to_be32(QCOW_MAGIC), 2125 .version = cpu_to_be32(version), 2126 .cluster_bits = cpu_to_be32(cluster_bits), 2127 .size = cpu_to_be64(0), 2128 .l1_table_offset = cpu_to_be64(0), 2129 .l1_size = cpu_to_be32(0), 2130 .refcount_table_offset = cpu_to_be64(cluster_size), 2131 .refcount_table_clusters = cpu_to_be32(1), 2132 .refcount_order = cpu_to_be32(refcount_order), 2133 .header_length = cpu_to_be32(sizeof(*header)), 2134 }; 2135 2136 if (flags & BLOCK_FLAG_ENCRYPT) { 2137 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2138 } else { 2139 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2140 } 2141 2142 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2143 header->compatible_features |= 2144 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2145 } 2146 2147 ret = bdrv_pwrite(bs, 0, header, cluster_size); 2148 g_free(header); 2149 if (ret < 0) { 2150 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2151 goto out; 2152 } 2153 2154 /* Write a refcount table with one refcount block */ 2155 refcount_table = g_malloc0(2 * cluster_size); 2156 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2157 ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size); 2158 g_free(refcount_table); 2159 2160 if (ret < 0) { 2161 error_setg_errno(errp, -ret, "Could not write refcount table"); 2162 goto out; 2163 } 2164 2165 bdrv_unref(bs); 2166 bs = NULL; 2167 2168 /* 2169 * And now open the image and make it consistent first (i.e. increase the 2170 * refcount of the cluster that is occupied by the header and the refcount 2171 * table) 2172 */ 2173 options = qdict_new(); 2174 qdict_put(options, "driver", qstring_from_str("qcow2")); 2175 ret = bdrv_open(&bs, filename, NULL, options, 2176 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, 2177 &local_err); 2178 if (ret < 0) { 2179 error_propagate(errp, local_err); 2180 goto out; 2181 } 2182 2183 ret = qcow2_alloc_clusters(bs, 3 * cluster_size); 2184 if (ret < 0) { 2185 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2186 "header and refcount table"); 2187 goto out; 2188 2189 } else if (ret != 0) { 2190 error_report("Huh, first cluster in empty image is already in use?"); 2191 abort(); 2192 } 2193 2194 /* Okay, now that we have a valid image, let's give it the right size */ 2195 ret = bdrv_truncate(bs, total_size); 2196 if (ret < 0) { 2197 error_setg_errno(errp, -ret, "Could not resize image"); 2198 goto out; 2199 } 2200 2201 /* Want a backing file? There you go.*/ 2202 if (backing_file) { 2203 ret = bdrv_change_backing_file(bs, backing_file, backing_format); 2204 if (ret < 0) { 2205 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2206 "with format '%s'", backing_file, backing_format); 2207 goto out; 2208 } 2209 } 2210 2211 /* And if we're supposed to preallocate metadata, do that now */ 2212 if (prealloc != PREALLOC_MODE_OFF) { 2213 BDRVQcow2State *s = bs->opaque; 2214 qemu_co_mutex_lock(&s->lock); 2215 ret = preallocate(bs); 2216 qemu_co_mutex_unlock(&s->lock); 2217 if (ret < 0) { 2218 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2219 goto out; 2220 } 2221 } 2222 2223 bdrv_unref(bs); 2224 bs = NULL; 2225 2226 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2227 options = qdict_new(); 2228 qdict_put(options, "driver", qstring_from_str("qcow2")); 2229 ret = bdrv_open(&bs, filename, NULL, options, 2230 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, 2231 &local_err); 2232 if (local_err) { 2233 error_propagate(errp, local_err); 2234 goto out; 2235 } 2236 2237 ret = 0; 2238 out: 2239 if (bs) { 2240 bdrv_unref(bs); 2241 } 2242 return ret; 2243 } 2244 2245 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2246 { 2247 char *backing_file = NULL; 2248 char *backing_fmt = NULL; 2249 char *buf = NULL; 2250 uint64_t size = 0; 2251 int flags = 0; 2252 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2253 PreallocMode prealloc; 2254 int version = 3; 2255 uint64_t refcount_bits = 16; 2256 int refcount_order; 2257 Error *local_err = NULL; 2258 int ret; 2259 2260 /* Read out options */ 2261 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2262 BDRV_SECTOR_SIZE); 2263 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2264 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2265 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2266 flags |= BLOCK_FLAG_ENCRYPT; 2267 } 2268 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2269 DEFAULT_CLUSTER_SIZE); 2270 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2271 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2272 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2273 &local_err); 2274 if (local_err) { 2275 error_propagate(errp, local_err); 2276 ret = -EINVAL; 2277 goto finish; 2278 } 2279 g_free(buf); 2280 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2281 if (!buf) { 2282 /* keep the default */ 2283 } else if (!strcmp(buf, "0.10")) { 2284 version = 2; 2285 } else if (!strcmp(buf, "1.1")) { 2286 version = 3; 2287 } else { 2288 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2289 ret = -EINVAL; 2290 goto finish; 2291 } 2292 2293 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2294 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2295 } 2296 2297 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2298 error_setg(errp, "Backing file and preallocation cannot be used at " 2299 "the same time"); 2300 ret = -EINVAL; 2301 goto finish; 2302 } 2303 2304 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2305 error_setg(errp, "Lazy refcounts only supported with compatibility " 2306 "level 1.1 and above (use compat=1.1 or greater)"); 2307 ret = -EINVAL; 2308 goto finish; 2309 } 2310 2311 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2312 refcount_bits); 2313 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2314 error_setg(errp, "Refcount width must be a power of two and may not " 2315 "exceed 64 bits"); 2316 ret = -EINVAL; 2317 goto finish; 2318 } 2319 2320 if (version < 3 && refcount_bits != 16) { 2321 error_setg(errp, "Different refcount widths than 16 bits require " 2322 "compatibility level 1.1 or above (use compat=1.1 or " 2323 "greater)"); 2324 ret = -EINVAL; 2325 goto finish; 2326 } 2327 2328 refcount_order = ctz32(refcount_bits); 2329 2330 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2331 cluster_size, prealloc, opts, version, refcount_order, 2332 &local_err); 2333 if (local_err) { 2334 error_propagate(errp, local_err); 2335 } 2336 2337 finish: 2338 g_free(backing_file); 2339 g_free(backing_fmt); 2340 g_free(buf); 2341 return ret; 2342 } 2343 2344 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2345 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2346 { 2347 int ret; 2348 BDRVQcow2State *s = bs->opaque; 2349 2350 /* Emulate misaligned zero writes */ 2351 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { 2352 return -ENOTSUP; 2353 } 2354 2355 /* Whatever is left can use real zero clusters */ 2356 qemu_co_mutex_lock(&s->lock); 2357 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2358 nb_sectors); 2359 qemu_co_mutex_unlock(&s->lock); 2360 2361 return ret; 2362 } 2363 2364 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2365 int64_t sector_num, int nb_sectors) 2366 { 2367 int ret; 2368 BDRVQcow2State *s = bs->opaque; 2369 2370 qemu_co_mutex_lock(&s->lock); 2371 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2372 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2373 qemu_co_mutex_unlock(&s->lock); 2374 return ret; 2375 } 2376 2377 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2378 { 2379 BDRVQcow2State *s = bs->opaque; 2380 int64_t new_l1_size; 2381 int ret; 2382 2383 if (offset & 511) { 2384 error_report("The new size must be a multiple of 512"); 2385 return -EINVAL; 2386 } 2387 2388 /* cannot proceed if image has snapshots */ 2389 if (s->nb_snapshots) { 2390 error_report("Can't resize an image which has snapshots"); 2391 return -ENOTSUP; 2392 } 2393 2394 /* shrinking is currently not supported */ 2395 if (offset < bs->total_sectors * 512) { 2396 error_report("qcow2 doesn't support shrinking images yet"); 2397 return -ENOTSUP; 2398 } 2399 2400 new_l1_size = size_to_l1(s, offset); 2401 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2402 if (ret < 0) { 2403 return ret; 2404 } 2405 2406 /* write updated header.size */ 2407 offset = cpu_to_be64(offset); 2408 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), 2409 &offset, sizeof(uint64_t)); 2410 if (ret < 0) { 2411 return ret; 2412 } 2413 2414 s->l1_vm_state_index = new_l1_size; 2415 return 0; 2416 } 2417 2418 /* XXX: put compressed sectors first, then all the cluster aligned 2419 tables to avoid losing bytes in alignment */ 2420 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2421 const uint8_t *buf, int nb_sectors) 2422 { 2423 BDRVQcow2State *s = bs->opaque; 2424 z_stream strm; 2425 int ret, out_len; 2426 uint8_t *out_buf; 2427 uint64_t cluster_offset; 2428 2429 if (nb_sectors == 0) { 2430 /* align end of file to a sector boundary to ease reading with 2431 sector based I/Os */ 2432 cluster_offset = bdrv_getlength(bs->file->bs); 2433 return bdrv_truncate(bs->file->bs, cluster_offset); 2434 } 2435 2436 if (nb_sectors != s->cluster_sectors) { 2437 ret = -EINVAL; 2438 2439 /* Zero-pad last write if image size is not cluster aligned */ 2440 if (sector_num + nb_sectors == bs->total_sectors && 2441 nb_sectors < s->cluster_sectors) { 2442 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2443 memset(pad_buf, 0, s->cluster_size); 2444 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2445 ret = qcow2_write_compressed(bs, sector_num, 2446 pad_buf, s->cluster_sectors); 2447 qemu_vfree(pad_buf); 2448 } 2449 return ret; 2450 } 2451 2452 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2453 2454 /* best compression, small window, no zlib header */ 2455 memset(&strm, 0, sizeof(strm)); 2456 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2457 Z_DEFLATED, -12, 2458 9, Z_DEFAULT_STRATEGY); 2459 if (ret != 0) { 2460 ret = -EINVAL; 2461 goto fail; 2462 } 2463 2464 strm.avail_in = s->cluster_size; 2465 strm.next_in = (uint8_t *)buf; 2466 strm.avail_out = s->cluster_size; 2467 strm.next_out = out_buf; 2468 2469 ret = deflate(&strm, Z_FINISH); 2470 if (ret != Z_STREAM_END && ret != Z_OK) { 2471 deflateEnd(&strm); 2472 ret = -EINVAL; 2473 goto fail; 2474 } 2475 out_len = strm.next_out - out_buf; 2476 2477 deflateEnd(&strm); 2478 2479 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2480 /* could not compress: write normal cluster */ 2481 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2482 if (ret < 0) { 2483 goto fail; 2484 } 2485 } else { 2486 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2487 sector_num << 9, out_len); 2488 if (!cluster_offset) { 2489 ret = -EIO; 2490 goto fail; 2491 } 2492 cluster_offset &= s->cluster_offset_mask; 2493 2494 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2495 if (ret < 0) { 2496 goto fail; 2497 } 2498 2499 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2500 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 2501 if (ret < 0) { 2502 goto fail; 2503 } 2504 } 2505 2506 ret = 0; 2507 fail: 2508 g_free(out_buf); 2509 return ret; 2510 } 2511 2512 static int make_completely_empty(BlockDriverState *bs) 2513 { 2514 BDRVQcow2State *s = bs->opaque; 2515 int ret, l1_clusters; 2516 int64_t offset; 2517 uint64_t *new_reftable = NULL; 2518 uint64_t rt_entry, l1_size2; 2519 struct { 2520 uint64_t l1_offset; 2521 uint64_t reftable_offset; 2522 uint32_t reftable_clusters; 2523 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2524 2525 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2526 if (ret < 0) { 2527 goto fail; 2528 } 2529 2530 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2531 if (ret < 0) { 2532 goto fail; 2533 } 2534 2535 /* Refcounts will be broken utterly */ 2536 ret = qcow2_mark_dirty(bs); 2537 if (ret < 0) { 2538 goto fail; 2539 } 2540 2541 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2542 2543 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2544 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2545 2546 /* After this call, neither the in-memory nor the on-disk refcount 2547 * information accurately describe the actual references */ 2548 2549 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, 2550 l1_clusters * s->cluster_sectors, 0); 2551 if (ret < 0) { 2552 goto fail_broken_refcounts; 2553 } 2554 memset(s->l1_table, 0, l1_size2); 2555 2556 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2557 2558 /* Overwrite enough clusters at the beginning of the sectors to place 2559 * the refcount table, a refcount block and the L1 table in; this may 2560 * overwrite parts of the existing refcount and L1 table, which is not 2561 * an issue because the dirty flag is set, complete data loss is in fact 2562 * desired and partial data loss is consequently fine as well */ 2563 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, 2564 (2 + l1_clusters) * s->cluster_size / 2565 BDRV_SECTOR_SIZE, 0); 2566 /* This call (even if it failed overall) may have overwritten on-disk 2567 * refcount structures; in that case, the in-memory refcount information 2568 * will probably differ from the on-disk information which makes the BDS 2569 * unusable */ 2570 if (ret < 0) { 2571 goto fail_broken_refcounts; 2572 } 2573 2574 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2575 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2576 2577 /* "Create" an empty reftable (one cluster) directly after the image 2578 * header and an empty L1 table three clusters after the image header; 2579 * the cluster between those two will be used as the first refblock */ 2580 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2581 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2582 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2583 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset), 2584 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2585 if (ret < 0) { 2586 goto fail_broken_refcounts; 2587 } 2588 2589 s->l1_table_offset = 3 * s->cluster_size; 2590 2591 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2592 if (!new_reftable) { 2593 ret = -ENOMEM; 2594 goto fail_broken_refcounts; 2595 } 2596 2597 s->refcount_table_offset = s->cluster_size; 2598 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2599 2600 g_free(s->refcount_table); 2601 s->refcount_table = new_reftable; 2602 new_reftable = NULL; 2603 2604 /* Now the in-memory refcount information again corresponds to the on-disk 2605 * information (reftable is empty and no refblocks (the refblock cache is 2606 * empty)); however, this means some clusters (e.g. the image header) are 2607 * referenced, but not refcounted, but the normal qcow2 code assumes that 2608 * the in-memory information is always correct */ 2609 2610 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2611 2612 /* Enter the first refblock into the reftable */ 2613 rt_entry = cpu_to_be64(2 * s->cluster_size); 2614 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size, 2615 &rt_entry, sizeof(rt_entry)); 2616 if (ret < 0) { 2617 goto fail_broken_refcounts; 2618 } 2619 s->refcount_table[0] = 2 * s->cluster_size; 2620 2621 s->free_cluster_index = 0; 2622 assert(3 + l1_clusters <= s->refcount_block_size); 2623 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2624 if (offset < 0) { 2625 ret = offset; 2626 goto fail_broken_refcounts; 2627 } else if (offset > 0) { 2628 error_report("First cluster in emptied image is in use"); 2629 abort(); 2630 } 2631 2632 /* Now finally the in-memory information corresponds to the on-disk 2633 * structures and is correct */ 2634 ret = qcow2_mark_clean(bs); 2635 if (ret < 0) { 2636 goto fail; 2637 } 2638 2639 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2640 if (ret < 0) { 2641 goto fail; 2642 } 2643 2644 return 0; 2645 2646 fail_broken_refcounts: 2647 /* The BDS is unusable at this point. If we wanted to make it usable, we 2648 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2649 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2650 * again. However, because the functions which could have caused this error 2651 * path to be taken are used by those functions as well, it's very likely 2652 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2653 bs->drv = NULL; 2654 2655 fail: 2656 g_free(new_reftable); 2657 return ret; 2658 } 2659 2660 static int qcow2_make_empty(BlockDriverState *bs) 2661 { 2662 BDRVQcow2State *s = bs->opaque; 2663 uint64_t start_sector; 2664 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2665 int l1_clusters, ret = 0; 2666 2667 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2668 2669 if (s->qcow_version >= 3 && !s->snapshots && 2670 3 + l1_clusters <= s->refcount_block_size) { 2671 /* The following function only works for qcow2 v3 images (it requires 2672 * the dirty flag) and only as long as there are no snapshots (because 2673 * it completely empties the image). Furthermore, the L1 table and three 2674 * additional clusters (image header, refcount table, one refcount 2675 * block) have to fit inside one refcount block. */ 2676 return make_completely_empty(bs); 2677 } 2678 2679 /* This fallback code simply discards every active cluster; this is slow, 2680 * but works in all cases */ 2681 for (start_sector = 0; start_sector < bs->total_sectors; 2682 start_sector += sector_step) 2683 { 2684 /* As this function is generally used after committing an external 2685 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2686 * default action for this kind of discard is to pass the discard, 2687 * which will ideally result in an actually smaller image file, as 2688 * is probably desired. */ 2689 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2690 MIN(sector_step, 2691 bs->total_sectors - start_sector), 2692 QCOW2_DISCARD_SNAPSHOT, true); 2693 if (ret < 0) { 2694 break; 2695 } 2696 } 2697 2698 return ret; 2699 } 2700 2701 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2702 { 2703 BDRVQcow2State *s = bs->opaque; 2704 int ret; 2705 2706 qemu_co_mutex_lock(&s->lock); 2707 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2708 if (ret < 0) { 2709 qemu_co_mutex_unlock(&s->lock); 2710 return ret; 2711 } 2712 2713 if (qcow2_need_accurate_refcounts(s)) { 2714 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2715 if (ret < 0) { 2716 qemu_co_mutex_unlock(&s->lock); 2717 return ret; 2718 } 2719 } 2720 qemu_co_mutex_unlock(&s->lock); 2721 2722 return 0; 2723 } 2724 2725 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2726 { 2727 BDRVQcow2State *s = bs->opaque; 2728 bdi->unallocated_blocks_are_zero = true; 2729 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2730 bdi->cluster_size = s->cluster_size; 2731 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2732 return 0; 2733 } 2734 2735 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2736 { 2737 BDRVQcow2State *s = bs->opaque; 2738 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2739 2740 *spec_info = (ImageInfoSpecific){ 2741 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2742 .u.qcow2 = g_new(ImageInfoSpecificQCow2, 1), 2743 }; 2744 if (s->qcow_version == 2) { 2745 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2746 .compat = g_strdup("0.10"), 2747 .refcount_bits = s->refcount_bits, 2748 }; 2749 } else if (s->qcow_version == 3) { 2750 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2751 .compat = g_strdup("1.1"), 2752 .lazy_refcounts = s->compatible_features & 2753 QCOW2_COMPAT_LAZY_REFCOUNTS, 2754 .has_lazy_refcounts = true, 2755 .corrupt = s->incompatible_features & 2756 QCOW2_INCOMPAT_CORRUPT, 2757 .has_corrupt = true, 2758 .refcount_bits = s->refcount_bits, 2759 }; 2760 } 2761 2762 return spec_info; 2763 } 2764 2765 #if 0 2766 static void dump_refcounts(BlockDriverState *bs) 2767 { 2768 BDRVQcow2State *s = bs->opaque; 2769 int64_t nb_clusters, k, k1, size; 2770 int refcount; 2771 2772 size = bdrv_getlength(bs->file->bs); 2773 nb_clusters = size_to_clusters(s, size); 2774 for(k = 0; k < nb_clusters;) { 2775 k1 = k; 2776 refcount = get_refcount(bs, k); 2777 k++; 2778 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2779 k++; 2780 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2781 k - k1); 2782 } 2783 } 2784 #endif 2785 2786 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2787 int64_t pos) 2788 { 2789 BDRVQcow2State *s = bs->opaque; 2790 int64_t total_sectors = bs->total_sectors; 2791 bool zero_beyond_eof = bs->zero_beyond_eof; 2792 int ret; 2793 2794 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2795 bs->zero_beyond_eof = false; 2796 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2797 bs->zero_beyond_eof = zero_beyond_eof; 2798 2799 /* bdrv_co_do_writev will have increased the total_sectors value to include 2800 * the VM state - the VM state is however not an actual part of the block 2801 * device, therefore, we need to restore the old value. */ 2802 bs->total_sectors = total_sectors; 2803 2804 return ret; 2805 } 2806 2807 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2808 int64_t pos, int size) 2809 { 2810 BDRVQcow2State *s = bs->opaque; 2811 bool zero_beyond_eof = bs->zero_beyond_eof; 2812 int ret; 2813 2814 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2815 bs->zero_beyond_eof = false; 2816 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2817 bs->zero_beyond_eof = zero_beyond_eof; 2818 2819 return ret; 2820 } 2821 2822 /* 2823 * Downgrades an image's version. To achieve this, any incompatible features 2824 * have to be removed. 2825 */ 2826 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2827 BlockDriverAmendStatusCB *status_cb) 2828 { 2829 BDRVQcow2State *s = bs->opaque; 2830 int current_version = s->qcow_version; 2831 int ret; 2832 2833 if (target_version == current_version) { 2834 return 0; 2835 } else if (target_version > current_version) { 2836 return -EINVAL; 2837 } else if (target_version != 2) { 2838 return -EINVAL; 2839 } 2840 2841 if (s->refcount_order != 4) { 2842 /* we would have to convert the image to a refcount_order == 4 image 2843 * here; however, since qemu (at the time of writing this) does not 2844 * support anything different than 4 anyway, there is no point in doing 2845 * so right now; however, we should error out (if qemu supports this in 2846 * the future and this code has not been adapted) */ 2847 error_report("qcow2_downgrade: Image refcount orders other than 4 are " 2848 "currently not supported."); 2849 return -ENOTSUP; 2850 } 2851 2852 /* clear incompatible features */ 2853 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2854 ret = qcow2_mark_clean(bs); 2855 if (ret < 0) { 2856 return ret; 2857 } 2858 } 2859 2860 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2861 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2862 * best thing to do anyway */ 2863 2864 if (s->incompatible_features) { 2865 return -ENOTSUP; 2866 } 2867 2868 /* since we can ignore compatible features, we can set them to 0 as well */ 2869 s->compatible_features = 0; 2870 /* if lazy refcounts have been used, they have already been fixed through 2871 * clearing the dirty flag */ 2872 2873 /* clearing autoclear features is trivial */ 2874 s->autoclear_features = 0; 2875 2876 ret = qcow2_expand_zero_clusters(bs, status_cb); 2877 if (ret < 0) { 2878 return ret; 2879 } 2880 2881 s->qcow_version = target_version; 2882 ret = qcow2_update_header(bs); 2883 if (ret < 0) { 2884 s->qcow_version = current_version; 2885 return ret; 2886 } 2887 return 0; 2888 } 2889 2890 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 2891 BlockDriverAmendStatusCB *status_cb) 2892 { 2893 BDRVQcow2State *s = bs->opaque; 2894 int old_version = s->qcow_version, new_version = old_version; 2895 uint64_t new_size = 0; 2896 const char *backing_file = NULL, *backing_format = NULL; 2897 bool lazy_refcounts = s->use_lazy_refcounts; 2898 const char *compat = NULL; 2899 uint64_t cluster_size = s->cluster_size; 2900 bool encrypt; 2901 int ret; 2902 QemuOptDesc *desc = opts->list->desc; 2903 2904 while (desc && desc->name) { 2905 if (!qemu_opt_find(opts, desc->name)) { 2906 /* only change explicitly defined options */ 2907 desc++; 2908 continue; 2909 } 2910 2911 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 2912 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 2913 if (!compat) { 2914 /* preserve default */ 2915 } else if (!strcmp(compat, "0.10")) { 2916 new_version = 2; 2917 } else if (!strcmp(compat, "1.1")) { 2918 new_version = 3; 2919 } else { 2920 fprintf(stderr, "Unknown compatibility level %s.\n", compat); 2921 return -EINVAL; 2922 } 2923 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 2924 fprintf(stderr, "Cannot change preallocation mode.\n"); 2925 return -ENOTSUP; 2926 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 2927 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 2928 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 2929 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 2930 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 2931 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 2932 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 2933 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 2934 !!s->cipher); 2935 2936 if (encrypt != !!s->cipher) { 2937 fprintf(stderr, "Changing the encryption flag is not " 2938 "supported.\n"); 2939 return -ENOTSUP; 2940 } 2941 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 2942 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 2943 cluster_size); 2944 if (cluster_size != s->cluster_size) { 2945 fprintf(stderr, "Changing the cluster size is not " 2946 "supported.\n"); 2947 return -ENOTSUP; 2948 } 2949 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 2950 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 2951 lazy_refcounts); 2952 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 2953 error_report("Cannot change refcount entry width"); 2954 return -ENOTSUP; 2955 } else { 2956 /* if this assertion fails, this probably means a new option was 2957 * added without having it covered here */ 2958 assert(false); 2959 } 2960 2961 desc++; 2962 } 2963 2964 if (new_version != old_version) { 2965 if (new_version > old_version) { 2966 /* Upgrade */ 2967 s->qcow_version = new_version; 2968 ret = qcow2_update_header(bs); 2969 if (ret < 0) { 2970 s->qcow_version = old_version; 2971 return ret; 2972 } 2973 } else { 2974 ret = qcow2_downgrade(bs, new_version, status_cb); 2975 if (ret < 0) { 2976 return ret; 2977 } 2978 } 2979 } 2980 2981 if (backing_file || backing_format) { 2982 ret = qcow2_change_backing_file(bs, 2983 backing_file ?: s->image_backing_file, 2984 backing_format ?: s->image_backing_format); 2985 if (ret < 0) { 2986 return ret; 2987 } 2988 } 2989 2990 if (s->use_lazy_refcounts != lazy_refcounts) { 2991 if (lazy_refcounts) { 2992 if (s->qcow_version < 3) { 2993 fprintf(stderr, "Lazy refcounts only supported with compatibility " 2994 "level 1.1 and above (use compat=1.1 or greater)\n"); 2995 return -EINVAL; 2996 } 2997 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 2998 ret = qcow2_update_header(bs); 2999 if (ret < 0) { 3000 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3001 return ret; 3002 } 3003 s->use_lazy_refcounts = true; 3004 } else { 3005 /* make image clean first */ 3006 ret = qcow2_mark_clean(bs); 3007 if (ret < 0) { 3008 return ret; 3009 } 3010 /* now disallow lazy refcounts */ 3011 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3012 ret = qcow2_update_header(bs); 3013 if (ret < 0) { 3014 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3015 return ret; 3016 } 3017 s->use_lazy_refcounts = false; 3018 } 3019 } 3020 3021 if (new_size) { 3022 ret = bdrv_truncate(bs, new_size); 3023 if (ret < 0) { 3024 return ret; 3025 } 3026 } 3027 3028 return 0; 3029 } 3030 3031 /* 3032 * If offset or size are negative, respectively, they will not be included in 3033 * the BLOCK_IMAGE_CORRUPTED event emitted. 3034 * fatal will be ignored for read-only BDS; corruptions found there will always 3035 * be considered non-fatal. 3036 */ 3037 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3038 int64_t size, const char *message_format, ...) 3039 { 3040 BDRVQcow2State *s = bs->opaque; 3041 const char *node_name; 3042 char *message; 3043 va_list ap; 3044 3045 fatal = fatal && !bs->read_only; 3046 3047 if (s->signaled_corruption && 3048 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3049 { 3050 return; 3051 } 3052 3053 va_start(ap, message_format); 3054 message = g_strdup_vprintf(message_format, ap); 3055 va_end(ap); 3056 3057 if (fatal) { 3058 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3059 "corruption events will be suppressed\n", message); 3060 } else { 3061 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3062 "corruption events will be suppressed\n", message); 3063 } 3064 3065 node_name = bdrv_get_node_name(bs); 3066 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3067 *node_name != '\0', node_name, 3068 message, offset >= 0, offset, 3069 size >= 0, size, 3070 fatal, &error_abort); 3071 g_free(message); 3072 3073 if (fatal) { 3074 qcow2_mark_corrupt(bs); 3075 bs->drv = NULL; /* make BDS unusable */ 3076 } 3077 3078 s->signaled_corruption = true; 3079 } 3080 3081 static QemuOptsList qcow2_create_opts = { 3082 .name = "qcow2-create-opts", 3083 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3084 .desc = { 3085 { 3086 .name = BLOCK_OPT_SIZE, 3087 .type = QEMU_OPT_SIZE, 3088 .help = "Virtual disk size" 3089 }, 3090 { 3091 .name = BLOCK_OPT_COMPAT_LEVEL, 3092 .type = QEMU_OPT_STRING, 3093 .help = "Compatibility level (0.10 or 1.1)" 3094 }, 3095 { 3096 .name = BLOCK_OPT_BACKING_FILE, 3097 .type = QEMU_OPT_STRING, 3098 .help = "File name of a base image" 3099 }, 3100 { 3101 .name = BLOCK_OPT_BACKING_FMT, 3102 .type = QEMU_OPT_STRING, 3103 .help = "Image format of the base image" 3104 }, 3105 { 3106 .name = BLOCK_OPT_ENCRYPT, 3107 .type = QEMU_OPT_BOOL, 3108 .help = "Encrypt the image", 3109 .def_value_str = "off" 3110 }, 3111 { 3112 .name = BLOCK_OPT_CLUSTER_SIZE, 3113 .type = QEMU_OPT_SIZE, 3114 .help = "qcow2 cluster size", 3115 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3116 }, 3117 { 3118 .name = BLOCK_OPT_PREALLOC, 3119 .type = QEMU_OPT_STRING, 3120 .help = "Preallocation mode (allowed values: off, metadata, " 3121 "falloc, full)" 3122 }, 3123 { 3124 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3125 .type = QEMU_OPT_BOOL, 3126 .help = "Postpone refcount updates", 3127 .def_value_str = "off" 3128 }, 3129 { 3130 .name = BLOCK_OPT_REFCOUNT_BITS, 3131 .type = QEMU_OPT_NUMBER, 3132 .help = "Width of a reference count entry in bits", 3133 .def_value_str = "16" 3134 }, 3135 { /* end of list */ } 3136 } 3137 }; 3138 3139 BlockDriver bdrv_qcow2 = { 3140 .format_name = "qcow2", 3141 .instance_size = sizeof(BDRVQcow2State), 3142 .bdrv_probe = qcow2_probe, 3143 .bdrv_open = qcow2_open, 3144 .bdrv_close = qcow2_close, 3145 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3146 .bdrv_reopen_commit = qcow2_reopen_commit, 3147 .bdrv_reopen_abort = qcow2_reopen_abort, 3148 .bdrv_create = qcow2_create, 3149 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3150 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3151 .bdrv_set_key = qcow2_set_key, 3152 3153 .bdrv_co_readv = qcow2_co_readv, 3154 .bdrv_co_writev = qcow2_co_writev, 3155 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3156 3157 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3158 .bdrv_co_discard = qcow2_co_discard, 3159 .bdrv_truncate = qcow2_truncate, 3160 .bdrv_write_compressed = qcow2_write_compressed, 3161 .bdrv_make_empty = qcow2_make_empty, 3162 3163 .bdrv_snapshot_create = qcow2_snapshot_create, 3164 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3165 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3166 .bdrv_snapshot_list = qcow2_snapshot_list, 3167 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3168 .bdrv_get_info = qcow2_get_info, 3169 .bdrv_get_specific_info = qcow2_get_specific_info, 3170 3171 .bdrv_save_vmstate = qcow2_save_vmstate, 3172 .bdrv_load_vmstate = qcow2_load_vmstate, 3173 3174 .supports_backing = true, 3175 .bdrv_change_backing_file = qcow2_change_backing_file, 3176 3177 .bdrv_refresh_limits = qcow2_refresh_limits, 3178 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3179 3180 .create_opts = &qcow2_create_opts, 3181 .bdrv_check = qcow2_check, 3182 .bdrv_amend_options = qcow2_amend_options, 3183 3184 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3185 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3186 }; 3187 3188 static void bdrv_qcow2_init(void) 3189 { 3190 bdrv_register(&bdrv_qcow2); 3191 } 3192 3193 block_init(bdrv_qcow2_init); 3194