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 void qcow2_join_options(QDict *options, QDict *old_options) 1286 { 1287 bool has_new_overlap_template = 1288 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1289 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1290 bool has_new_total_cache_size = 1291 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1292 bool has_all_cache_options; 1293 1294 /* New overlap template overrides all old overlap options */ 1295 if (has_new_overlap_template) { 1296 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1297 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1298 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1299 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1300 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1301 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1302 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1303 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1304 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1305 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1306 } 1307 1308 /* New total cache size overrides all old options */ 1309 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1310 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1311 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1312 } 1313 1314 qdict_join(options, old_options, false); 1315 1316 /* 1317 * If after merging all cache size options are set, an old total size is 1318 * overwritten. Do keep all options, however, if all three are new. The 1319 * resulting error message is what we want to happen. 1320 */ 1321 has_all_cache_options = 1322 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1323 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1324 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1325 1326 if (has_all_cache_options && !has_new_total_cache_size) { 1327 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1328 } 1329 } 1330 1331 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1332 int64_t sector_num, int nb_sectors, int *pnum) 1333 { 1334 BDRVQcow2State *s = bs->opaque; 1335 uint64_t cluster_offset; 1336 int index_in_cluster, ret; 1337 int64_t status = 0; 1338 1339 *pnum = nb_sectors; 1340 qemu_co_mutex_lock(&s->lock); 1341 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); 1342 qemu_co_mutex_unlock(&s->lock); 1343 if (ret < 0) { 1344 return ret; 1345 } 1346 1347 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1348 !s->cipher) { 1349 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1350 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1351 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1352 } 1353 if (ret == QCOW2_CLUSTER_ZERO) { 1354 status |= BDRV_BLOCK_ZERO; 1355 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1356 status |= BDRV_BLOCK_DATA; 1357 } 1358 return status; 1359 } 1360 1361 /* handle reading after the end of the backing file */ 1362 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1363 int64_t sector_num, int nb_sectors) 1364 { 1365 int n1; 1366 if ((sector_num + nb_sectors) <= bs->total_sectors) 1367 return nb_sectors; 1368 if (sector_num >= bs->total_sectors) 1369 n1 = 0; 1370 else 1371 n1 = bs->total_sectors - sector_num; 1372 1373 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1374 1375 return n1; 1376 } 1377 1378 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1379 int remaining_sectors, QEMUIOVector *qiov) 1380 { 1381 BDRVQcow2State *s = bs->opaque; 1382 int index_in_cluster, n1; 1383 int ret; 1384 int cur_nr_sectors; /* number of sectors in current iteration */ 1385 uint64_t cluster_offset = 0; 1386 uint64_t bytes_done = 0; 1387 QEMUIOVector hd_qiov; 1388 uint8_t *cluster_data = NULL; 1389 1390 qemu_iovec_init(&hd_qiov, qiov->niov); 1391 1392 qemu_co_mutex_lock(&s->lock); 1393 1394 while (remaining_sectors != 0) { 1395 1396 /* prepare next request */ 1397 cur_nr_sectors = remaining_sectors; 1398 if (s->cipher) { 1399 cur_nr_sectors = MIN(cur_nr_sectors, 1400 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1401 } 1402 1403 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1404 &cur_nr_sectors, &cluster_offset); 1405 if (ret < 0) { 1406 goto fail; 1407 } 1408 1409 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1410 1411 qemu_iovec_reset(&hd_qiov); 1412 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1413 cur_nr_sectors * 512); 1414 1415 switch (ret) { 1416 case QCOW2_CLUSTER_UNALLOCATED: 1417 1418 if (bs->backing) { 1419 /* read from the base image */ 1420 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1421 sector_num, cur_nr_sectors); 1422 if (n1 > 0) { 1423 QEMUIOVector local_qiov; 1424 1425 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1426 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1427 n1 * BDRV_SECTOR_SIZE); 1428 1429 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1430 qemu_co_mutex_unlock(&s->lock); 1431 ret = bdrv_co_readv(bs->backing->bs, sector_num, 1432 n1, &local_qiov); 1433 qemu_co_mutex_lock(&s->lock); 1434 1435 qemu_iovec_destroy(&local_qiov); 1436 1437 if (ret < 0) { 1438 goto fail; 1439 } 1440 } 1441 } else { 1442 /* Note: in this case, no need to wait */ 1443 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1444 } 1445 break; 1446 1447 case QCOW2_CLUSTER_ZERO: 1448 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1449 break; 1450 1451 case QCOW2_CLUSTER_COMPRESSED: 1452 /* add AIO support for compressed blocks ? */ 1453 ret = qcow2_decompress_cluster(bs, cluster_offset); 1454 if (ret < 0) { 1455 goto fail; 1456 } 1457 1458 qemu_iovec_from_buf(&hd_qiov, 0, 1459 s->cluster_cache + index_in_cluster * 512, 1460 512 * cur_nr_sectors); 1461 break; 1462 1463 case QCOW2_CLUSTER_NORMAL: 1464 if ((cluster_offset & 511) != 0) { 1465 ret = -EIO; 1466 goto fail; 1467 } 1468 1469 if (bs->encrypted) { 1470 assert(s->cipher); 1471 1472 /* 1473 * For encrypted images, read everything into a temporary 1474 * contiguous buffer on which the AES functions can work. 1475 */ 1476 if (!cluster_data) { 1477 cluster_data = 1478 qemu_try_blockalign(bs->file->bs, 1479 QCOW_MAX_CRYPT_CLUSTERS 1480 * s->cluster_size); 1481 if (cluster_data == NULL) { 1482 ret = -ENOMEM; 1483 goto fail; 1484 } 1485 } 1486 1487 assert(cur_nr_sectors <= 1488 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1489 qemu_iovec_reset(&hd_qiov); 1490 qemu_iovec_add(&hd_qiov, cluster_data, 1491 512 * cur_nr_sectors); 1492 } 1493 1494 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1495 qemu_co_mutex_unlock(&s->lock); 1496 ret = bdrv_co_readv(bs->file->bs, 1497 (cluster_offset >> 9) + index_in_cluster, 1498 cur_nr_sectors, &hd_qiov); 1499 qemu_co_mutex_lock(&s->lock); 1500 if (ret < 0) { 1501 goto fail; 1502 } 1503 if (bs->encrypted) { 1504 assert(s->cipher); 1505 Error *err = NULL; 1506 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1507 cluster_data, cur_nr_sectors, false, 1508 &err) < 0) { 1509 error_free(err); 1510 ret = -EIO; 1511 goto fail; 1512 } 1513 qemu_iovec_from_buf(qiov, bytes_done, 1514 cluster_data, 512 * cur_nr_sectors); 1515 } 1516 break; 1517 1518 default: 1519 g_assert_not_reached(); 1520 ret = -EIO; 1521 goto fail; 1522 } 1523 1524 remaining_sectors -= cur_nr_sectors; 1525 sector_num += cur_nr_sectors; 1526 bytes_done += cur_nr_sectors * 512; 1527 } 1528 ret = 0; 1529 1530 fail: 1531 qemu_co_mutex_unlock(&s->lock); 1532 1533 qemu_iovec_destroy(&hd_qiov); 1534 qemu_vfree(cluster_data); 1535 1536 return ret; 1537 } 1538 1539 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1540 int64_t sector_num, 1541 int remaining_sectors, 1542 QEMUIOVector *qiov) 1543 { 1544 BDRVQcow2State *s = bs->opaque; 1545 int index_in_cluster; 1546 int ret; 1547 int cur_nr_sectors; /* number of sectors in current iteration */ 1548 uint64_t cluster_offset; 1549 QEMUIOVector hd_qiov; 1550 uint64_t bytes_done = 0; 1551 uint8_t *cluster_data = NULL; 1552 QCowL2Meta *l2meta = NULL; 1553 1554 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1555 remaining_sectors); 1556 1557 qemu_iovec_init(&hd_qiov, qiov->niov); 1558 1559 s->cluster_cache_offset = -1; /* disable compressed cache */ 1560 1561 qemu_co_mutex_lock(&s->lock); 1562 1563 while (remaining_sectors != 0) { 1564 1565 l2meta = NULL; 1566 1567 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1568 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1569 cur_nr_sectors = remaining_sectors; 1570 if (bs->encrypted && 1571 cur_nr_sectors > 1572 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1573 cur_nr_sectors = 1574 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1575 } 1576 1577 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1578 &cur_nr_sectors, &cluster_offset, &l2meta); 1579 if (ret < 0) { 1580 goto fail; 1581 } 1582 1583 assert((cluster_offset & 511) == 0); 1584 1585 qemu_iovec_reset(&hd_qiov); 1586 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1587 cur_nr_sectors * 512); 1588 1589 if (bs->encrypted) { 1590 Error *err = NULL; 1591 assert(s->cipher); 1592 if (!cluster_data) { 1593 cluster_data = qemu_try_blockalign(bs->file->bs, 1594 QCOW_MAX_CRYPT_CLUSTERS 1595 * s->cluster_size); 1596 if (cluster_data == NULL) { 1597 ret = -ENOMEM; 1598 goto fail; 1599 } 1600 } 1601 1602 assert(hd_qiov.size <= 1603 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1604 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1605 1606 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1607 cluster_data, cur_nr_sectors, 1608 true, &err) < 0) { 1609 error_free(err); 1610 ret = -EIO; 1611 goto fail; 1612 } 1613 1614 qemu_iovec_reset(&hd_qiov); 1615 qemu_iovec_add(&hd_qiov, cluster_data, 1616 cur_nr_sectors * 512); 1617 } 1618 1619 ret = qcow2_pre_write_overlap_check(bs, 0, 1620 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1621 cur_nr_sectors * BDRV_SECTOR_SIZE); 1622 if (ret < 0) { 1623 goto fail; 1624 } 1625 1626 qemu_co_mutex_unlock(&s->lock); 1627 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1628 trace_qcow2_writev_data(qemu_coroutine_self(), 1629 (cluster_offset >> 9) + index_in_cluster); 1630 ret = bdrv_co_writev(bs->file->bs, 1631 (cluster_offset >> 9) + index_in_cluster, 1632 cur_nr_sectors, &hd_qiov); 1633 qemu_co_mutex_lock(&s->lock); 1634 if (ret < 0) { 1635 goto fail; 1636 } 1637 1638 while (l2meta != NULL) { 1639 QCowL2Meta *next; 1640 1641 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1642 if (ret < 0) { 1643 goto fail; 1644 } 1645 1646 /* Take the request off the list of running requests */ 1647 if (l2meta->nb_clusters != 0) { 1648 QLIST_REMOVE(l2meta, next_in_flight); 1649 } 1650 1651 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1652 1653 next = l2meta->next; 1654 g_free(l2meta); 1655 l2meta = next; 1656 } 1657 1658 remaining_sectors -= cur_nr_sectors; 1659 sector_num += cur_nr_sectors; 1660 bytes_done += cur_nr_sectors * 512; 1661 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1662 } 1663 ret = 0; 1664 1665 fail: 1666 qemu_co_mutex_unlock(&s->lock); 1667 1668 while (l2meta != NULL) { 1669 QCowL2Meta *next; 1670 1671 if (l2meta->nb_clusters != 0) { 1672 QLIST_REMOVE(l2meta, next_in_flight); 1673 } 1674 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1675 1676 next = l2meta->next; 1677 g_free(l2meta); 1678 l2meta = next; 1679 } 1680 1681 qemu_iovec_destroy(&hd_qiov); 1682 qemu_vfree(cluster_data); 1683 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1684 1685 return ret; 1686 } 1687 1688 static void qcow2_close(BlockDriverState *bs) 1689 { 1690 BDRVQcow2State *s = bs->opaque; 1691 qemu_vfree(s->l1_table); 1692 /* else pre-write overlap checks in cache_destroy may crash */ 1693 s->l1_table = NULL; 1694 1695 if (!(bs->open_flags & BDRV_O_INCOMING)) { 1696 int ret1, ret2; 1697 1698 ret1 = qcow2_cache_flush(bs, s->l2_table_cache); 1699 ret2 = qcow2_cache_flush(bs, s->refcount_block_cache); 1700 1701 if (ret1) { 1702 error_report("Failed to flush the L2 table cache: %s", 1703 strerror(-ret1)); 1704 } 1705 if (ret2) { 1706 error_report("Failed to flush the refcount block cache: %s", 1707 strerror(-ret2)); 1708 } 1709 1710 if (!ret1 && !ret2) { 1711 qcow2_mark_clean(bs); 1712 } 1713 } 1714 1715 cache_clean_timer_del(bs); 1716 qcow2_cache_destroy(bs, s->l2_table_cache); 1717 qcow2_cache_destroy(bs, s->refcount_block_cache); 1718 1719 qcrypto_cipher_free(s->cipher); 1720 s->cipher = NULL; 1721 1722 g_free(s->unknown_header_fields); 1723 cleanup_unknown_header_ext(bs); 1724 1725 g_free(s->image_backing_file); 1726 g_free(s->image_backing_format); 1727 1728 g_free(s->cluster_cache); 1729 qemu_vfree(s->cluster_data); 1730 qcow2_refcount_close(bs); 1731 qcow2_free_snapshots(bs); 1732 } 1733 1734 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1735 { 1736 BDRVQcow2State *s = bs->opaque; 1737 int flags = s->flags; 1738 QCryptoCipher *cipher = NULL; 1739 QDict *options; 1740 Error *local_err = NULL; 1741 int ret; 1742 1743 /* 1744 * Backing files are read-only which makes all of their metadata immutable, 1745 * that means we don't have to worry about reopening them here. 1746 */ 1747 1748 cipher = s->cipher; 1749 s->cipher = NULL; 1750 1751 qcow2_close(bs); 1752 1753 bdrv_invalidate_cache(bs->file->bs, &local_err); 1754 if (local_err) { 1755 error_propagate(errp, local_err); 1756 return; 1757 } 1758 1759 memset(s, 0, sizeof(BDRVQcow2State)); 1760 options = qdict_clone_shallow(bs->options); 1761 1762 ret = qcow2_open(bs, options, flags, &local_err); 1763 QDECREF(options); 1764 if (local_err) { 1765 error_setg(errp, "Could not reopen qcow2 layer: %s", 1766 error_get_pretty(local_err)); 1767 error_free(local_err); 1768 return; 1769 } else if (ret < 0) { 1770 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1771 return; 1772 } 1773 1774 s->cipher = cipher; 1775 } 1776 1777 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1778 size_t len, size_t buflen) 1779 { 1780 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1781 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1782 1783 if (buflen < ext_len) { 1784 return -ENOSPC; 1785 } 1786 1787 *ext_backing_fmt = (QCowExtension) { 1788 .magic = cpu_to_be32(magic), 1789 .len = cpu_to_be32(len), 1790 }; 1791 memcpy(buf + sizeof(QCowExtension), s, len); 1792 1793 return ext_len; 1794 } 1795 1796 /* 1797 * Updates the qcow2 header, including the variable length parts of it, i.e. 1798 * the backing file name and all extensions. qcow2 was not designed to allow 1799 * such changes, so if we run out of space (we can only use the first cluster) 1800 * this function may fail. 1801 * 1802 * Returns 0 on success, -errno in error cases. 1803 */ 1804 int qcow2_update_header(BlockDriverState *bs) 1805 { 1806 BDRVQcow2State *s = bs->opaque; 1807 QCowHeader *header; 1808 char *buf; 1809 size_t buflen = s->cluster_size; 1810 int ret; 1811 uint64_t total_size; 1812 uint32_t refcount_table_clusters; 1813 size_t header_length; 1814 Qcow2UnknownHeaderExtension *uext; 1815 1816 buf = qemu_blockalign(bs, buflen); 1817 1818 /* Header structure */ 1819 header = (QCowHeader*) buf; 1820 1821 if (buflen < sizeof(*header)) { 1822 ret = -ENOSPC; 1823 goto fail; 1824 } 1825 1826 header_length = sizeof(*header) + s->unknown_header_fields_size; 1827 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1828 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1829 1830 *header = (QCowHeader) { 1831 /* Version 2 fields */ 1832 .magic = cpu_to_be32(QCOW_MAGIC), 1833 .version = cpu_to_be32(s->qcow_version), 1834 .backing_file_offset = 0, 1835 .backing_file_size = 0, 1836 .cluster_bits = cpu_to_be32(s->cluster_bits), 1837 .size = cpu_to_be64(total_size), 1838 .crypt_method = cpu_to_be32(s->crypt_method_header), 1839 .l1_size = cpu_to_be32(s->l1_size), 1840 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1841 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1842 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1843 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1844 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1845 1846 /* Version 3 fields */ 1847 .incompatible_features = cpu_to_be64(s->incompatible_features), 1848 .compatible_features = cpu_to_be64(s->compatible_features), 1849 .autoclear_features = cpu_to_be64(s->autoclear_features), 1850 .refcount_order = cpu_to_be32(s->refcount_order), 1851 .header_length = cpu_to_be32(header_length), 1852 }; 1853 1854 /* For older versions, write a shorter header */ 1855 switch (s->qcow_version) { 1856 case 2: 1857 ret = offsetof(QCowHeader, incompatible_features); 1858 break; 1859 case 3: 1860 ret = sizeof(*header); 1861 break; 1862 default: 1863 ret = -EINVAL; 1864 goto fail; 1865 } 1866 1867 buf += ret; 1868 buflen -= ret; 1869 memset(buf, 0, buflen); 1870 1871 /* Preserve any unknown field in the header */ 1872 if (s->unknown_header_fields_size) { 1873 if (buflen < s->unknown_header_fields_size) { 1874 ret = -ENOSPC; 1875 goto fail; 1876 } 1877 1878 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1879 buf += s->unknown_header_fields_size; 1880 buflen -= s->unknown_header_fields_size; 1881 } 1882 1883 /* Backing file format header extension */ 1884 if (s->image_backing_format) { 1885 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1886 s->image_backing_format, 1887 strlen(s->image_backing_format), 1888 buflen); 1889 if (ret < 0) { 1890 goto fail; 1891 } 1892 1893 buf += ret; 1894 buflen -= ret; 1895 } 1896 1897 /* Feature table */ 1898 Qcow2Feature features[] = { 1899 { 1900 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1901 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1902 .name = "dirty bit", 1903 }, 1904 { 1905 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1906 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1907 .name = "corrupt bit", 1908 }, 1909 { 1910 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1911 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1912 .name = "lazy refcounts", 1913 }, 1914 }; 1915 1916 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1917 features, sizeof(features), buflen); 1918 if (ret < 0) { 1919 goto fail; 1920 } 1921 buf += ret; 1922 buflen -= ret; 1923 1924 /* Keep unknown header extensions */ 1925 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1926 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1927 if (ret < 0) { 1928 goto fail; 1929 } 1930 1931 buf += ret; 1932 buflen -= ret; 1933 } 1934 1935 /* End of header extensions */ 1936 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1937 if (ret < 0) { 1938 goto fail; 1939 } 1940 1941 buf += ret; 1942 buflen -= ret; 1943 1944 /* Backing file name */ 1945 if (s->image_backing_file) { 1946 size_t backing_file_len = strlen(s->image_backing_file); 1947 1948 if (buflen < backing_file_len) { 1949 ret = -ENOSPC; 1950 goto fail; 1951 } 1952 1953 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1954 strncpy(buf, s->image_backing_file, buflen); 1955 1956 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1957 header->backing_file_size = cpu_to_be32(backing_file_len); 1958 } 1959 1960 /* Write the new header */ 1961 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size); 1962 if (ret < 0) { 1963 goto fail; 1964 } 1965 1966 ret = 0; 1967 fail: 1968 qemu_vfree(header); 1969 return ret; 1970 } 1971 1972 static int qcow2_change_backing_file(BlockDriverState *bs, 1973 const char *backing_file, const char *backing_fmt) 1974 { 1975 BDRVQcow2State *s = bs->opaque; 1976 1977 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1978 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1979 1980 g_free(s->image_backing_file); 1981 g_free(s->image_backing_format); 1982 1983 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 1984 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 1985 1986 return qcow2_update_header(bs); 1987 } 1988 1989 static int preallocate(BlockDriverState *bs) 1990 { 1991 uint64_t nb_sectors; 1992 uint64_t offset; 1993 uint64_t host_offset = 0; 1994 int num; 1995 int ret; 1996 QCowL2Meta *meta; 1997 1998 nb_sectors = bdrv_nb_sectors(bs); 1999 offset = 0; 2000 2001 while (nb_sectors) { 2002 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 2003 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 2004 &host_offset, &meta); 2005 if (ret < 0) { 2006 return ret; 2007 } 2008 2009 while (meta) { 2010 QCowL2Meta *next = meta->next; 2011 2012 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2013 if (ret < 0) { 2014 qcow2_free_any_clusters(bs, meta->alloc_offset, 2015 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2016 return ret; 2017 } 2018 2019 /* There are no dependent requests, but we need to remove our 2020 * request from the list of in-flight requests */ 2021 QLIST_REMOVE(meta, next_in_flight); 2022 2023 g_free(meta); 2024 meta = next; 2025 } 2026 2027 /* TODO Preallocate data if requested */ 2028 2029 nb_sectors -= num; 2030 offset += num << BDRV_SECTOR_BITS; 2031 } 2032 2033 /* 2034 * It is expected that the image file is large enough to actually contain 2035 * all of the allocated clusters (otherwise we get failing reads after 2036 * EOF). Extend the image to the last allocated sector. 2037 */ 2038 if (host_offset != 0) { 2039 uint8_t buf[BDRV_SECTOR_SIZE]; 2040 memset(buf, 0, BDRV_SECTOR_SIZE); 2041 ret = bdrv_write(bs->file->bs, 2042 (host_offset >> BDRV_SECTOR_BITS) + num - 1, 2043 buf, 1); 2044 if (ret < 0) { 2045 return ret; 2046 } 2047 } 2048 2049 return 0; 2050 } 2051 2052 static int qcow2_create2(const char *filename, int64_t total_size, 2053 const char *backing_file, const char *backing_format, 2054 int flags, size_t cluster_size, PreallocMode prealloc, 2055 QemuOpts *opts, int version, int refcount_order, 2056 Error **errp) 2057 { 2058 int cluster_bits; 2059 QDict *options; 2060 2061 /* Calculate cluster_bits */ 2062 cluster_bits = ctz32(cluster_size); 2063 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2064 (1 << cluster_bits) != cluster_size) 2065 { 2066 error_setg(errp, "Cluster size must be a power of two between %d and " 2067 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2068 return -EINVAL; 2069 } 2070 2071 /* 2072 * Open the image file and write a minimal qcow2 header. 2073 * 2074 * We keep things simple and start with a zero-sized image. We also 2075 * do without refcount blocks or a L1 table for now. We'll fix the 2076 * inconsistency later. 2077 * 2078 * We do need a refcount table because growing the refcount table means 2079 * allocating two new refcount blocks - the seconds of which would be at 2080 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2081 * size for any qcow2 image. 2082 */ 2083 BlockDriverState* bs; 2084 QCowHeader *header; 2085 uint64_t* refcount_table; 2086 Error *local_err = NULL; 2087 int ret; 2088 2089 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2090 /* Note: The following calculation does not need to be exact; if it is a 2091 * bit off, either some bytes will be "leaked" (which is fine) or we 2092 * will need to increase the file size by some bytes (which is fine, 2093 * too, as long as the bulk is allocated here). Therefore, using 2094 * floating point arithmetic is fine. */ 2095 int64_t meta_size = 0; 2096 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2097 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2098 int refblock_bits, refblock_size; 2099 /* refcount entry size in bytes */ 2100 double rces = (1 << refcount_order) / 8.; 2101 2102 /* see qcow2_open() */ 2103 refblock_bits = cluster_bits - (refcount_order - 3); 2104 refblock_size = 1 << refblock_bits; 2105 2106 /* header: 1 cluster */ 2107 meta_size += cluster_size; 2108 2109 /* total size of L2 tables */ 2110 nl2e = aligned_total_size / cluster_size; 2111 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2112 meta_size += nl2e * sizeof(uint64_t); 2113 2114 /* total size of L1 tables */ 2115 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2116 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2117 meta_size += nl1e * sizeof(uint64_t); 2118 2119 /* total size of refcount blocks 2120 * 2121 * note: every host cluster is reference-counted, including metadata 2122 * (even refcount blocks are recursively included). 2123 * Let: 2124 * a = total_size (this is the guest disk size) 2125 * m = meta size not including refcount blocks and refcount tables 2126 * c = cluster size 2127 * y1 = number of refcount blocks entries 2128 * y2 = meta size including everything 2129 * rces = refcount entry size in bytes 2130 * then, 2131 * y1 = (y2 + a)/c 2132 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2133 * we can get y1: 2134 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2135 */ 2136 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2137 / (cluster_size - rces - rces * sizeof(uint64_t) 2138 / cluster_size); 2139 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2140 2141 /* total size of refcount tables */ 2142 nreftablee = nrefblocke / refblock_size; 2143 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2144 meta_size += nreftablee * sizeof(uint64_t); 2145 2146 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2147 aligned_total_size + meta_size, &error_abort); 2148 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2149 &error_abort); 2150 } 2151 2152 ret = bdrv_create_file(filename, opts, &local_err); 2153 if (ret < 0) { 2154 error_propagate(errp, local_err); 2155 return ret; 2156 } 2157 2158 bs = NULL; 2159 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 2160 &local_err); 2161 if (ret < 0) { 2162 error_propagate(errp, local_err); 2163 return ret; 2164 } 2165 2166 /* Write the header */ 2167 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2168 header = g_malloc0(cluster_size); 2169 *header = (QCowHeader) { 2170 .magic = cpu_to_be32(QCOW_MAGIC), 2171 .version = cpu_to_be32(version), 2172 .cluster_bits = cpu_to_be32(cluster_bits), 2173 .size = cpu_to_be64(0), 2174 .l1_table_offset = cpu_to_be64(0), 2175 .l1_size = cpu_to_be32(0), 2176 .refcount_table_offset = cpu_to_be64(cluster_size), 2177 .refcount_table_clusters = cpu_to_be32(1), 2178 .refcount_order = cpu_to_be32(refcount_order), 2179 .header_length = cpu_to_be32(sizeof(*header)), 2180 }; 2181 2182 if (flags & BLOCK_FLAG_ENCRYPT) { 2183 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2184 } else { 2185 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2186 } 2187 2188 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2189 header->compatible_features |= 2190 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2191 } 2192 2193 ret = bdrv_pwrite(bs, 0, header, cluster_size); 2194 g_free(header); 2195 if (ret < 0) { 2196 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2197 goto out; 2198 } 2199 2200 /* Write a refcount table with one refcount block */ 2201 refcount_table = g_malloc0(2 * cluster_size); 2202 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2203 ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size); 2204 g_free(refcount_table); 2205 2206 if (ret < 0) { 2207 error_setg_errno(errp, -ret, "Could not write refcount table"); 2208 goto out; 2209 } 2210 2211 bdrv_unref(bs); 2212 bs = NULL; 2213 2214 /* 2215 * And now open the image and make it consistent first (i.e. increase the 2216 * refcount of the cluster that is occupied by the header and the refcount 2217 * table) 2218 */ 2219 options = qdict_new(); 2220 qdict_put(options, "driver", qstring_from_str("qcow2")); 2221 ret = bdrv_open(&bs, filename, NULL, options, 2222 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, 2223 &local_err); 2224 if (ret < 0) { 2225 error_propagate(errp, local_err); 2226 goto out; 2227 } 2228 2229 ret = qcow2_alloc_clusters(bs, 3 * cluster_size); 2230 if (ret < 0) { 2231 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2232 "header and refcount table"); 2233 goto out; 2234 2235 } else if (ret != 0) { 2236 error_report("Huh, first cluster in empty image is already in use?"); 2237 abort(); 2238 } 2239 2240 /* Okay, now that we have a valid image, let's give it the right size */ 2241 ret = bdrv_truncate(bs, total_size); 2242 if (ret < 0) { 2243 error_setg_errno(errp, -ret, "Could not resize image"); 2244 goto out; 2245 } 2246 2247 /* Want a backing file? There you go.*/ 2248 if (backing_file) { 2249 ret = bdrv_change_backing_file(bs, backing_file, backing_format); 2250 if (ret < 0) { 2251 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2252 "with format '%s'", backing_file, backing_format); 2253 goto out; 2254 } 2255 } 2256 2257 /* And if we're supposed to preallocate metadata, do that now */ 2258 if (prealloc != PREALLOC_MODE_OFF) { 2259 BDRVQcow2State *s = bs->opaque; 2260 qemu_co_mutex_lock(&s->lock); 2261 ret = preallocate(bs); 2262 qemu_co_mutex_unlock(&s->lock); 2263 if (ret < 0) { 2264 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2265 goto out; 2266 } 2267 } 2268 2269 bdrv_unref(bs); 2270 bs = NULL; 2271 2272 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2273 options = qdict_new(); 2274 qdict_put(options, "driver", qstring_from_str("qcow2")); 2275 ret = bdrv_open(&bs, filename, NULL, options, 2276 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, 2277 &local_err); 2278 if (local_err) { 2279 error_propagate(errp, local_err); 2280 goto out; 2281 } 2282 2283 ret = 0; 2284 out: 2285 if (bs) { 2286 bdrv_unref(bs); 2287 } 2288 return ret; 2289 } 2290 2291 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2292 { 2293 char *backing_file = NULL; 2294 char *backing_fmt = NULL; 2295 char *buf = NULL; 2296 uint64_t size = 0; 2297 int flags = 0; 2298 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2299 PreallocMode prealloc; 2300 int version = 3; 2301 uint64_t refcount_bits = 16; 2302 int refcount_order; 2303 Error *local_err = NULL; 2304 int ret; 2305 2306 /* Read out options */ 2307 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2308 BDRV_SECTOR_SIZE); 2309 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2310 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2311 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2312 flags |= BLOCK_FLAG_ENCRYPT; 2313 } 2314 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2315 DEFAULT_CLUSTER_SIZE); 2316 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2317 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2318 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2319 &local_err); 2320 if (local_err) { 2321 error_propagate(errp, local_err); 2322 ret = -EINVAL; 2323 goto finish; 2324 } 2325 g_free(buf); 2326 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2327 if (!buf) { 2328 /* keep the default */ 2329 } else if (!strcmp(buf, "0.10")) { 2330 version = 2; 2331 } else if (!strcmp(buf, "1.1")) { 2332 version = 3; 2333 } else { 2334 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2335 ret = -EINVAL; 2336 goto finish; 2337 } 2338 2339 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2340 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2341 } 2342 2343 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2344 error_setg(errp, "Backing file and preallocation cannot be used at " 2345 "the same time"); 2346 ret = -EINVAL; 2347 goto finish; 2348 } 2349 2350 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2351 error_setg(errp, "Lazy refcounts only supported with compatibility " 2352 "level 1.1 and above (use compat=1.1 or greater)"); 2353 ret = -EINVAL; 2354 goto finish; 2355 } 2356 2357 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2358 refcount_bits); 2359 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2360 error_setg(errp, "Refcount width must be a power of two and may not " 2361 "exceed 64 bits"); 2362 ret = -EINVAL; 2363 goto finish; 2364 } 2365 2366 if (version < 3 && refcount_bits != 16) { 2367 error_setg(errp, "Different refcount widths than 16 bits require " 2368 "compatibility level 1.1 or above (use compat=1.1 or " 2369 "greater)"); 2370 ret = -EINVAL; 2371 goto finish; 2372 } 2373 2374 refcount_order = ctz32(refcount_bits); 2375 2376 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2377 cluster_size, prealloc, opts, version, refcount_order, 2378 &local_err); 2379 if (local_err) { 2380 error_propagate(errp, local_err); 2381 } 2382 2383 finish: 2384 g_free(backing_file); 2385 g_free(backing_fmt); 2386 g_free(buf); 2387 return ret; 2388 } 2389 2390 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2391 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2392 { 2393 int ret; 2394 BDRVQcow2State *s = bs->opaque; 2395 2396 /* Emulate misaligned zero writes */ 2397 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { 2398 return -ENOTSUP; 2399 } 2400 2401 /* Whatever is left can use real zero clusters */ 2402 qemu_co_mutex_lock(&s->lock); 2403 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2404 nb_sectors); 2405 qemu_co_mutex_unlock(&s->lock); 2406 2407 return ret; 2408 } 2409 2410 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2411 int64_t sector_num, int nb_sectors) 2412 { 2413 int ret; 2414 BDRVQcow2State *s = bs->opaque; 2415 2416 qemu_co_mutex_lock(&s->lock); 2417 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2418 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2419 qemu_co_mutex_unlock(&s->lock); 2420 return ret; 2421 } 2422 2423 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2424 { 2425 BDRVQcow2State *s = bs->opaque; 2426 int64_t new_l1_size; 2427 int ret; 2428 2429 if (offset & 511) { 2430 error_report("The new size must be a multiple of 512"); 2431 return -EINVAL; 2432 } 2433 2434 /* cannot proceed if image has snapshots */ 2435 if (s->nb_snapshots) { 2436 error_report("Can't resize an image which has snapshots"); 2437 return -ENOTSUP; 2438 } 2439 2440 /* shrinking is currently not supported */ 2441 if (offset < bs->total_sectors * 512) { 2442 error_report("qcow2 doesn't support shrinking images yet"); 2443 return -ENOTSUP; 2444 } 2445 2446 new_l1_size = size_to_l1(s, offset); 2447 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2448 if (ret < 0) { 2449 return ret; 2450 } 2451 2452 /* write updated header.size */ 2453 offset = cpu_to_be64(offset); 2454 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), 2455 &offset, sizeof(uint64_t)); 2456 if (ret < 0) { 2457 return ret; 2458 } 2459 2460 s->l1_vm_state_index = new_l1_size; 2461 return 0; 2462 } 2463 2464 /* XXX: put compressed sectors first, then all the cluster aligned 2465 tables to avoid losing bytes in alignment */ 2466 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2467 const uint8_t *buf, int nb_sectors) 2468 { 2469 BDRVQcow2State *s = bs->opaque; 2470 z_stream strm; 2471 int ret, out_len; 2472 uint8_t *out_buf; 2473 uint64_t cluster_offset; 2474 2475 if (nb_sectors == 0) { 2476 /* align end of file to a sector boundary to ease reading with 2477 sector based I/Os */ 2478 cluster_offset = bdrv_getlength(bs->file->bs); 2479 return bdrv_truncate(bs->file->bs, cluster_offset); 2480 } 2481 2482 if (nb_sectors != s->cluster_sectors) { 2483 ret = -EINVAL; 2484 2485 /* Zero-pad last write if image size is not cluster aligned */ 2486 if (sector_num + nb_sectors == bs->total_sectors && 2487 nb_sectors < s->cluster_sectors) { 2488 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2489 memset(pad_buf, 0, s->cluster_size); 2490 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2491 ret = qcow2_write_compressed(bs, sector_num, 2492 pad_buf, s->cluster_sectors); 2493 qemu_vfree(pad_buf); 2494 } 2495 return ret; 2496 } 2497 2498 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2499 2500 /* best compression, small window, no zlib header */ 2501 memset(&strm, 0, sizeof(strm)); 2502 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2503 Z_DEFLATED, -12, 2504 9, Z_DEFAULT_STRATEGY); 2505 if (ret != 0) { 2506 ret = -EINVAL; 2507 goto fail; 2508 } 2509 2510 strm.avail_in = s->cluster_size; 2511 strm.next_in = (uint8_t *)buf; 2512 strm.avail_out = s->cluster_size; 2513 strm.next_out = out_buf; 2514 2515 ret = deflate(&strm, Z_FINISH); 2516 if (ret != Z_STREAM_END && ret != Z_OK) { 2517 deflateEnd(&strm); 2518 ret = -EINVAL; 2519 goto fail; 2520 } 2521 out_len = strm.next_out - out_buf; 2522 2523 deflateEnd(&strm); 2524 2525 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2526 /* could not compress: write normal cluster */ 2527 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2528 if (ret < 0) { 2529 goto fail; 2530 } 2531 } else { 2532 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2533 sector_num << 9, out_len); 2534 if (!cluster_offset) { 2535 ret = -EIO; 2536 goto fail; 2537 } 2538 cluster_offset &= s->cluster_offset_mask; 2539 2540 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2541 if (ret < 0) { 2542 goto fail; 2543 } 2544 2545 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2546 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 2547 if (ret < 0) { 2548 goto fail; 2549 } 2550 } 2551 2552 ret = 0; 2553 fail: 2554 g_free(out_buf); 2555 return ret; 2556 } 2557 2558 static int make_completely_empty(BlockDriverState *bs) 2559 { 2560 BDRVQcow2State *s = bs->opaque; 2561 int ret, l1_clusters; 2562 int64_t offset; 2563 uint64_t *new_reftable = NULL; 2564 uint64_t rt_entry, l1_size2; 2565 struct { 2566 uint64_t l1_offset; 2567 uint64_t reftable_offset; 2568 uint32_t reftable_clusters; 2569 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2570 2571 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2572 if (ret < 0) { 2573 goto fail; 2574 } 2575 2576 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2577 if (ret < 0) { 2578 goto fail; 2579 } 2580 2581 /* Refcounts will be broken utterly */ 2582 ret = qcow2_mark_dirty(bs); 2583 if (ret < 0) { 2584 goto fail; 2585 } 2586 2587 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2588 2589 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2590 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2591 2592 /* After this call, neither the in-memory nor the on-disk refcount 2593 * information accurately describe the actual references */ 2594 2595 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, 2596 l1_clusters * s->cluster_sectors, 0); 2597 if (ret < 0) { 2598 goto fail_broken_refcounts; 2599 } 2600 memset(s->l1_table, 0, l1_size2); 2601 2602 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2603 2604 /* Overwrite enough clusters at the beginning of the sectors to place 2605 * the refcount table, a refcount block and the L1 table in; this may 2606 * overwrite parts of the existing refcount and L1 table, which is not 2607 * an issue because the dirty flag is set, complete data loss is in fact 2608 * desired and partial data loss is consequently fine as well */ 2609 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, 2610 (2 + l1_clusters) * s->cluster_size / 2611 BDRV_SECTOR_SIZE, 0); 2612 /* This call (even if it failed overall) may have overwritten on-disk 2613 * refcount structures; in that case, the in-memory refcount information 2614 * will probably differ from the on-disk information which makes the BDS 2615 * unusable */ 2616 if (ret < 0) { 2617 goto fail_broken_refcounts; 2618 } 2619 2620 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2621 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2622 2623 /* "Create" an empty reftable (one cluster) directly after the image 2624 * header and an empty L1 table three clusters after the image header; 2625 * the cluster between those two will be used as the first refblock */ 2626 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2627 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2628 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2629 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset), 2630 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2631 if (ret < 0) { 2632 goto fail_broken_refcounts; 2633 } 2634 2635 s->l1_table_offset = 3 * s->cluster_size; 2636 2637 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2638 if (!new_reftable) { 2639 ret = -ENOMEM; 2640 goto fail_broken_refcounts; 2641 } 2642 2643 s->refcount_table_offset = s->cluster_size; 2644 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2645 2646 g_free(s->refcount_table); 2647 s->refcount_table = new_reftable; 2648 new_reftable = NULL; 2649 2650 /* Now the in-memory refcount information again corresponds to the on-disk 2651 * information (reftable is empty and no refblocks (the refblock cache is 2652 * empty)); however, this means some clusters (e.g. the image header) are 2653 * referenced, but not refcounted, but the normal qcow2 code assumes that 2654 * the in-memory information is always correct */ 2655 2656 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2657 2658 /* Enter the first refblock into the reftable */ 2659 rt_entry = cpu_to_be64(2 * s->cluster_size); 2660 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size, 2661 &rt_entry, sizeof(rt_entry)); 2662 if (ret < 0) { 2663 goto fail_broken_refcounts; 2664 } 2665 s->refcount_table[0] = 2 * s->cluster_size; 2666 2667 s->free_cluster_index = 0; 2668 assert(3 + l1_clusters <= s->refcount_block_size); 2669 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2670 if (offset < 0) { 2671 ret = offset; 2672 goto fail_broken_refcounts; 2673 } else if (offset > 0) { 2674 error_report("First cluster in emptied image is in use"); 2675 abort(); 2676 } 2677 2678 /* Now finally the in-memory information corresponds to the on-disk 2679 * structures and is correct */ 2680 ret = qcow2_mark_clean(bs); 2681 if (ret < 0) { 2682 goto fail; 2683 } 2684 2685 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2686 if (ret < 0) { 2687 goto fail; 2688 } 2689 2690 return 0; 2691 2692 fail_broken_refcounts: 2693 /* The BDS is unusable at this point. If we wanted to make it usable, we 2694 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2695 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2696 * again. However, because the functions which could have caused this error 2697 * path to be taken are used by those functions as well, it's very likely 2698 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2699 bs->drv = NULL; 2700 2701 fail: 2702 g_free(new_reftable); 2703 return ret; 2704 } 2705 2706 static int qcow2_make_empty(BlockDriverState *bs) 2707 { 2708 BDRVQcow2State *s = bs->opaque; 2709 uint64_t start_sector; 2710 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2711 int l1_clusters, ret = 0; 2712 2713 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2714 2715 if (s->qcow_version >= 3 && !s->snapshots && 2716 3 + l1_clusters <= s->refcount_block_size) { 2717 /* The following function only works for qcow2 v3 images (it requires 2718 * the dirty flag) and only as long as there are no snapshots (because 2719 * it completely empties the image). Furthermore, the L1 table and three 2720 * additional clusters (image header, refcount table, one refcount 2721 * block) have to fit inside one refcount block. */ 2722 return make_completely_empty(bs); 2723 } 2724 2725 /* This fallback code simply discards every active cluster; this is slow, 2726 * but works in all cases */ 2727 for (start_sector = 0; start_sector < bs->total_sectors; 2728 start_sector += sector_step) 2729 { 2730 /* As this function is generally used after committing an external 2731 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2732 * default action for this kind of discard is to pass the discard, 2733 * which will ideally result in an actually smaller image file, as 2734 * is probably desired. */ 2735 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2736 MIN(sector_step, 2737 bs->total_sectors - start_sector), 2738 QCOW2_DISCARD_SNAPSHOT, true); 2739 if (ret < 0) { 2740 break; 2741 } 2742 } 2743 2744 return ret; 2745 } 2746 2747 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2748 { 2749 BDRVQcow2State *s = bs->opaque; 2750 int ret; 2751 2752 qemu_co_mutex_lock(&s->lock); 2753 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2754 if (ret < 0) { 2755 qemu_co_mutex_unlock(&s->lock); 2756 return ret; 2757 } 2758 2759 if (qcow2_need_accurate_refcounts(s)) { 2760 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2761 if (ret < 0) { 2762 qemu_co_mutex_unlock(&s->lock); 2763 return ret; 2764 } 2765 } 2766 qemu_co_mutex_unlock(&s->lock); 2767 2768 return 0; 2769 } 2770 2771 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2772 { 2773 BDRVQcow2State *s = bs->opaque; 2774 bdi->unallocated_blocks_are_zero = true; 2775 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2776 bdi->cluster_size = s->cluster_size; 2777 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2778 return 0; 2779 } 2780 2781 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2782 { 2783 BDRVQcow2State *s = bs->opaque; 2784 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2785 2786 *spec_info = (ImageInfoSpecific){ 2787 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2788 .u.qcow2 = g_new(ImageInfoSpecificQCow2, 1), 2789 }; 2790 if (s->qcow_version == 2) { 2791 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2792 .compat = g_strdup("0.10"), 2793 .refcount_bits = s->refcount_bits, 2794 }; 2795 } else if (s->qcow_version == 3) { 2796 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2797 .compat = g_strdup("1.1"), 2798 .lazy_refcounts = s->compatible_features & 2799 QCOW2_COMPAT_LAZY_REFCOUNTS, 2800 .has_lazy_refcounts = true, 2801 .corrupt = s->incompatible_features & 2802 QCOW2_INCOMPAT_CORRUPT, 2803 .has_corrupt = true, 2804 .refcount_bits = s->refcount_bits, 2805 }; 2806 } else { 2807 /* if this assertion fails, this probably means a new version was 2808 * added without having it covered here */ 2809 assert(false); 2810 } 2811 2812 return spec_info; 2813 } 2814 2815 #if 0 2816 static void dump_refcounts(BlockDriverState *bs) 2817 { 2818 BDRVQcow2State *s = bs->opaque; 2819 int64_t nb_clusters, k, k1, size; 2820 int refcount; 2821 2822 size = bdrv_getlength(bs->file->bs); 2823 nb_clusters = size_to_clusters(s, size); 2824 for(k = 0; k < nb_clusters;) { 2825 k1 = k; 2826 refcount = get_refcount(bs, k); 2827 k++; 2828 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2829 k++; 2830 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2831 k - k1); 2832 } 2833 } 2834 #endif 2835 2836 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2837 int64_t pos) 2838 { 2839 BDRVQcow2State *s = bs->opaque; 2840 int64_t total_sectors = bs->total_sectors; 2841 bool zero_beyond_eof = bs->zero_beyond_eof; 2842 int ret; 2843 2844 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2845 bs->zero_beyond_eof = false; 2846 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2847 bs->zero_beyond_eof = zero_beyond_eof; 2848 2849 /* bdrv_co_do_writev will have increased the total_sectors value to include 2850 * the VM state - the VM state is however not an actual part of the block 2851 * device, therefore, we need to restore the old value. */ 2852 bs->total_sectors = total_sectors; 2853 2854 return ret; 2855 } 2856 2857 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2858 int64_t pos, int size) 2859 { 2860 BDRVQcow2State *s = bs->opaque; 2861 bool zero_beyond_eof = bs->zero_beyond_eof; 2862 int ret; 2863 2864 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2865 bs->zero_beyond_eof = false; 2866 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2867 bs->zero_beyond_eof = zero_beyond_eof; 2868 2869 return ret; 2870 } 2871 2872 /* 2873 * Downgrades an image's version. To achieve this, any incompatible features 2874 * have to be removed. 2875 */ 2876 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2877 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2878 { 2879 BDRVQcow2State *s = bs->opaque; 2880 int current_version = s->qcow_version; 2881 int ret; 2882 2883 if (target_version == current_version) { 2884 return 0; 2885 } else if (target_version > current_version) { 2886 return -EINVAL; 2887 } else if (target_version != 2) { 2888 return -EINVAL; 2889 } 2890 2891 if (s->refcount_order != 4) { 2892 error_report("compat=0.10 requires refcount_bits=16"); 2893 return -ENOTSUP; 2894 } 2895 2896 /* clear incompatible features */ 2897 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2898 ret = qcow2_mark_clean(bs); 2899 if (ret < 0) { 2900 return ret; 2901 } 2902 } 2903 2904 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2905 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2906 * best thing to do anyway */ 2907 2908 if (s->incompatible_features) { 2909 return -ENOTSUP; 2910 } 2911 2912 /* since we can ignore compatible features, we can set them to 0 as well */ 2913 s->compatible_features = 0; 2914 /* if lazy refcounts have been used, they have already been fixed through 2915 * clearing the dirty flag */ 2916 2917 /* clearing autoclear features is trivial */ 2918 s->autoclear_features = 0; 2919 2920 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 2921 if (ret < 0) { 2922 return ret; 2923 } 2924 2925 s->qcow_version = target_version; 2926 ret = qcow2_update_header(bs); 2927 if (ret < 0) { 2928 s->qcow_version = current_version; 2929 return ret; 2930 } 2931 return 0; 2932 } 2933 2934 typedef enum Qcow2AmendOperation { 2935 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 2936 * statically initialized to so that the helper CB can discern the first 2937 * invocation from an operation change */ 2938 QCOW2_NO_OPERATION = 0, 2939 2940 QCOW2_CHANGING_REFCOUNT_ORDER, 2941 QCOW2_DOWNGRADING, 2942 } Qcow2AmendOperation; 2943 2944 typedef struct Qcow2AmendHelperCBInfo { 2945 /* The code coordinating the amend operations should only modify 2946 * these four fields; the rest will be managed by the CB */ 2947 BlockDriverAmendStatusCB *original_status_cb; 2948 void *original_cb_opaque; 2949 2950 Qcow2AmendOperation current_operation; 2951 2952 /* Total number of operations to perform (only set once) */ 2953 int total_operations; 2954 2955 /* The following fields are managed by the CB */ 2956 2957 /* Number of operations completed */ 2958 int operations_completed; 2959 2960 /* Cumulative offset of all completed operations */ 2961 int64_t offset_completed; 2962 2963 Qcow2AmendOperation last_operation; 2964 int64_t last_work_size; 2965 } Qcow2AmendHelperCBInfo; 2966 2967 static void qcow2_amend_helper_cb(BlockDriverState *bs, 2968 int64_t operation_offset, 2969 int64_t operation_work_size, void *opaque) 2970 { 2971 Qcow2AmendHelperCBInfo *info = opaque; 2972 int64_t current_work_size; 2973 int64_t projected_work_size; 2974 2975 if (info->current_operation != info->last_operation) { 2976 if (info->last_operation != QCOW2_NO_OPERATION) { 2977 info->offset_completed += info->last_work_size; 2978 info->operations_completed++; 2979 } 2980 2981 info->last_operation = info->current_operation; 2982 } 2983 2984 assert(info->total_operations > 0); 2985 assert(info->operations_completed < info->total_operations); 2986 2987 info->last_work_size = operation_work_size; 2988 2989 current_work_size = info->offset_completed + operation_work_size; 2990 2991 /* current_work_size is the total work size for (operations_completed + 1) 2992 * operations (which includes this one), so multiply it by the number of 2993 * operations not covered and divide it by the number of operations 2994 * covered to get a projection for the operations not covered */ 2995 projected_work_size = current_work_size * (info->total_operations - 2996 info->operations_completed - 1) 2997 / (info->operations_completed + 1); 2998 2999 info->original_status_cb(bs, info->offset_completed + operation_offset, 3000 current_work_size + projected_work_size, 3001 info->original_cb_opaque); 3002 } 3003 3004 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3005 BlockDriverAmendStatusCB *status_cb, 3006 void *cb_opaque) 3007 { 3008 BDRVQcow2State *s = bs->opaque; 3009 int old_version = s->qcow_version, new_version = old_version; 3010 uint64_t new_size = 0; 3011 const char *backing_file = NULL, *backing_format = NULL; 3012 bool lazy_refcounts = s->use_lazy_refcounts; 3013 const char *compat = NULL; 3014 uint64_t cluster_size = s->cluster_size; 3015 bool encrypt; 3016 int refcount_bits = s->refcount_bits; 3017 int ret; 3018 QemuOptDesc *desc = opts->list->desc; 3019 Qcow2AmendHelperCBInfo helper_cb_info; 3020 3021 while (desc && desc->name) { 3022 if (!qemu_opt_find(opts, desc->name)) { 3023 /* only change explicitly defined options */ 3024 desc++; 3025 continue; 3026 } 3027 3028 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3029 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3030 if (!compat) { 3031 /* preserve default */ 3032 } else if (!strcmp(compat, "0.10")) { 3033 new_version = 2; 3034 } else if (!strcmp(compat, "1.1")) { 3035 new_version = 3; 3036 } else { 3037 error_report("Unknown compatibility level %s", compat); 3038 return -EINVAL; 3039 } 3040 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3041 error_report("Cannot change preallocation mode"); 3042 return -ENOTSUP; 3043 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3044 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3045 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3046 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3047 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3048 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3049 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3050 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3051 !!s->cipher); 3052 3053 if (encrypt != !!s->cipher) { 3054 error_report("Changing the encryption flag is not supported"); 3055 return -ENOTSUP; 3056 } 3057 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3058 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3059 cluster_size); 3060 if (cluster_size != s->cluster_size) { 3061 error_report("Changing the cluster size is not supported"); 3062 return -ENOTSUP; 3063 } 3064 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3065 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3066 lazy_refcounts); 3067 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3068 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3069 refcount_bits); 3070 3071 if (refcount_bits <= 0 || refcount_bits > 64 || 3072 !is_power_of_2(refcount_bits)) 3073 { 3074 error_report("Refcount width must be a power of two and may " 3075 "not exceed 64 bits"); 3076 return -EINVAL; 3077 } 3078 } else { 3079 /* if this point is reached, this probably means a new option was 3080 * added without having it covered here */ 3081 abort(); 3082 } 3083 3084 desc++; 3085 } 3086 3087 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3088 .original_status_cb = status_cb, 3089 .original_cb_opaque = cb_opaque, 3090 .total_operations = (new_version < old_version) 3091 + (s->refcount_bits != refcount_bits) 3092 }; 3093 3094 /* Upgrade first (some features may require compat=1.1) */ 3095 if (new_version > old_version) { 3096 s->qcow_version = new_version; 3097 ret = qcow2_update_header(bs); 3098 if (ret < 0) { 3099 s->qcow_version = old_version; 3100 return ret; 3101 } 3102 } 3103 3104 if (s->refcount_bits != refcount_bits) { 3105 int refcount_order = ctz32(refcount_bits); 3106 Error *local_error = NULL; 3107 3108 if (new_version < 3 && refcount_bits != 16) { 3109 error_report("Different refcount widths than 16 bits require " 3110 "compatibility level 1.1 or above (use compat=1.1 or " 3111 "greater)"); 3112 return -EINVAL; 3113 } 3114 3115 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3116 ret = qcow2_change_refcount_order(bs, refcount_order, 3117 &qcow2_amend_helper_cb, 3118 &helper_cb_info, &local_error); 3119 if (ret < 0) { 3120 error_report_err(local_error); 3121 return ret; 3122 } 3123 } 3124 3125 if (backing_file || backing_format) { 3126 ret = qcow2_change_backing_file(bs, 3127 backing_file ?: s->image_backing_file, 3128 backing_format ?: s->image_backing_format); 3129 if (ret < 0) { 3130 return ret; 3131 } 3132 } 3133 3134 if (s->use_lazy_refcounts != lazy_refcounts) { 3135 if (lazy_refcounts) { 3136 if (new_version < 3) { 3137 error_report("Lazy refcounts only supported with compatibility " 3138 "level 1.1 and above (use compat=1.1 or greater)"); 3139 return -EINVAL; 3140 } 3141 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3142 ret = qcow2_update_header(bs); 3143 if (ret < 0) { 3144 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3145 return ret; 3146 } 3147 s->use_lazy_refcounts = true; 3148 } else { 3149 /* make image clean first */ 3150 ret = qcow2_mark_clean(bs); 3151 if (ret < 0) { 3152 return ret; 3153 } 3154 /* now disallow lazy refcounts */ 3155 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3156 ret = qcow2_update_header(bs); 3157 if (ret < 0) { 3158 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3159 return ret; 3160 } 3161 s->use_lazy_refcounts = false; 3162 } 3163 } 3164 3165 if (new_size) { 3166 ret = bdrv_truncate(bs, new_size); 3167 if (ret < 0) { 3168 return ret; 3169 } 3170 } 3171 3172 /* Downgrade last (so unsupported features can be removed before) */ 3173 if (new_version < old_version) { 3174 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3175 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3176 &helper_cb_info); 3177 if (ret < 0) { 3178 return ret; 3179 } 3180 } 3181 3182 return 0; 3183 } 3184 3185 /* 3186 * If offset or size are negative, respectively, they will not be included in 3187 * the BLOCK_IMAGE_CORRUPTED event emitted. 3188 * fatal will be ignored for read-only BDS; corruptions found there will always 3189 * be considered non-fatal. 3190 */ 3191 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3192 int64_t size, const char *message_format, ...) 3193 { 3194 BDRVQcow2State *s = bs->opaque; 3195 const char *node_name; 3196 char *message; 3197 va_list ap; 3198 3199 fatal = fatal && !bs->read_only; 3200 3201 if (s->signaled_corruption && 3202 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3203 { 3204 return; 3205 } 3206 3207 va_start(ap, message_format); 3208 message = g_strdup_vprintf(message_format, ap); 3209 va_end(ap); 3210 3211 if (fatal) { 3212 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3213 "corruption events will be suppressed\n", message); 3214 } else { 3215 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3216 "corruption events will be suppressed\n", message); 3217 } 3218 3219 node_name = bdrv_get_node_name(bs); 3220 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3221 *node_name != '\0', node_name, 3222 message, offset >= 0, offset, 3223 size >= 0, size, 3224 fatal, &error_abort); 3225 g_free(message); 3226 3227 if (fatal) { 3228 qcow2_mark_corrupt(bs); 3229 bs->drv = NULL; /* make BDS unusable */ 3230 } 3231 3232 s->signaled_corruption = true; 3233 } 3234 3235 static QemuOptsList qcow2_create_opts = { 3236 .name = "qcow2-create-opts", 3237 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3238 .desc = { 3239 { 3240 .name = BLOCK_OPT_SIZE, 3241 .type = QEMU_OPT_SIZE, 3242 .help = "Virtual disk size" 3243 }, 3244 { 3245 .name = BLOCK_OPT_COMPAT_LEVEL, 3246 .type = QEMU_OPT_STRING, 3247 .help = "Compatibility level (0.10 or 1.1)" 3248 }, 3249 { 3250 .name = BLOCK_OPT_BACKING_FILE, 3251 .type = QEMU_OPT_STRING, 3252 .help = "File name of a base image" 3253 }, 3254 { 3255 .name = BLOCK_OPT_BACKING_FMT, 3256 .type = QEMU_OPT_STRING, 3257 .help = "Image format of the base image" 3258 }, 3259 { 3260 .name = BLOCK_OPT_ENCRYPT, 3261 .type = QEMU_OPT_BOOL, 3262 .help = "Encrypt the image", 3263 .def_value_str = "off" 3264 }, 3265 { 3266 .name = BLOCK_OPT_CLUSTER_SIZE, 3267 .type = QEMU_OPT_SIZE, 3268 .help = "qcow2 cluster size", 3269 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3270 }, 3271 { 3272 .name = BLOCK_OPT_PREALLOC, 3273 .type = QEMU_OPT_STRING, 3274 .help = "Preallocation mode (allowed values: off, metadata, " 3275 "falloc, full)" 3276 }, 3277 { 3278 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3279 .type = QEMU_OPT_BOOL, 3280 .help = "Postpone refcount updates", 3281 .def_value_str = "off" 3282 }, 3283 { 3284 .name = BLOCK_OPT_REFCOUNT_BITS, 3285 .type = QEMU_OPT_NUMBER, 3286 .help = "Width of a reference count entry in bits", 3287 .def_value_str = "16" 3288 }, 3289 { /* end of list */ } 3290 } 3291 }; 3292 3293 BlockDriver bdrv_qcow2 = { 3294 .format_name = "qcow2", 3295 .instance_size = sizeof(BDRVQcow2State), 3296 .bdrv_probe = qcow2_probe, 3297 .bdrv_open = qcow2_open, 3298 .bdrv_close = qcow2_close, 3299 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3300 .bdrv_reopen_commit = qcow2_reopen_commit, 3301 .bdrv_reopen_abort = qcow2_reopen_abort, 3302 .bdrv_join_options = qcow2_join_options, 3303 .bdrv_create = qcow2_create, 3304 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3305 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3306 .bdrv_set_key = qcow2_set_key, 3307 3308 .bdrv_co_readv = qcow2_co_readv, 3309 .bdrv_co_writev = qcow2_co_writev, 3310 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3311 3312 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3313 .bdrv_co_discard = qcow2_co_discard, 3314 .bdrv_truncate = qcow2_truncate, 3315 .bdrv_write_compressed = qcow2_write_compressed, 3316 .bdrv_make_empty = qcow2_make_empty, 3317 3318 .bdrv_snapshot_create = qcow2_snapshot_create, 3319 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3320 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3321 .bdrv_snapshot_list = qcow2_snapshot_list, 3322 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3323 .bdrv_get_info = qcow2_get_info, 3324 .bdrv_get_specific_info = qcow2_get_specific_info, 3325 3326 .bdrv_save_vmstate = qcow2_save_vmstate, 3327 .bdrv_load_vmstate = qcow2_load_vmstate, 3328 3329 .supports_backing = true, 3330 .bdrv_change_backing_file = qcow2_change_backing_file, 3331 3332 .bdrv_refresh_limits = qcow2_refresh_limits, 3333 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3334 3335 .create_opts = &qcow2_create_opts, 3336 .bdrv_check = qcow2_check, 3337 .bdrv_amend_options = qcow2_amend_options, 3338 3339 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3340 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3341 }; 3342 3343 static void bdrv_qcow2_init(void) 3344 { 3345 bdrv_register(&bdrv_qcow2); 3346 } 3347 3348 block_init(bdrv_qcow2_init); 3349