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/osdep.h" 25 #include "qemu-common.h" 26 #include "block/block_int.h" 27 #include "sysemu/block-backend.h" 28 #include "qemu/module.h" 29 #include <zlib.h> 30 #include "block/qcow2.h" 31 #include "qemu/error-report.h" 32 #include "qapi/qmp/qerror.h" 33 #include "qapi/qmp/qbool.h" 34 #include "qapi/util.h" 35 #include "qapi/qmp/types.h" 36 #include "qapi-event.h" 37 #include "trace.h" 38 #include "qemu/option_int.h" 39 40 /* 41 Differences with QCOW: 42 43 - Support for multiple incremental snapshots. 44 - Memory management by reference counts. 45 - Clusters which have a reference count of one have the bit 46 QCOW_OFLAG_COPIED to optimize write performance. 47 - Size of compressed clusters is stored in sectors to reduce bit usage 48 in the cluster offsets. 49 - Support for storing additional data (such as the VM state) in the 50 snapshots. 51 - If a backing store is used, the cluster size is not constrained 52 (could be backported to QCOW). 53 - L2 tables have always a size of one cluster. 54 */ 55 56 57 typedef struct { 58 uint32_t magic; 59 uint32_t len; 60 } QEMU_PACKED QCowExtension; 61 62 #define QCOW2_EXT_MAGIC_END 0 63 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 64 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 65 66 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 67 { 68 const QCowHeader *cow_header = (const void *)buf; 69 70 if (buf_size >= sizeof(QCowHeader) && 71 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 72 be32_to_cpu(cow_header->version) >= 2) 73 return 100; 74 else 75 return 0; 76 } 77 78 79 /* 80 * read qcow2 extension and fill bs 81 * start reading from start_offset 82 * finish reading upon magic of value 0 or when end_offset reached 83 * unknown magic is skipped (future extension this version knows nothing about) 84 * return 0 upon success, non-0 otherwise 85 */ 86 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 87 uint64_t end_offset, void **p_feature_table, 88 Error **errp) 89 { 90 BDRVQcow2State *s = bs->opaque; 91 QCowExtension ext; 92 uint64_t offset; 93 int ret; 94 95 #ifdef DEBUG_EXT 96 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 97 #endif 98 offset = start_offset; 99 while (offset < end_offset) { 100 101 #ifdef DEBUG_EXT 102 /* Sanity check */ 103 if (offset > s->cluster_size) 104 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 105 106 printf("attempting to read extended header in offset %lu\n", offset); 107 #endif 108 109 ret = bdrv_pread(bs->file->bs, offset, &ext, sizeof(ext)); 110 if (ret < 0) { 111 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 112 "pread fail from offset %" PRIu64, offset); 113 return 1; 114 } 115 be32_to_cpus(&ext.magic); 116 be32_to_cpus(&ext.len); 117 offset += sizeof(ext); 118 #ifdef DEBUG_EXT 119 printf("ext.magic = 0x%x\n", ext.magic); 120 #endif 121 if (offset > end_offset || ext.len > end_offset - offset) { 122 error_setg(errp, "Header extension too large"); 123 return -EINVAL; 124 } 125 126 switch (ext.magic) { 127 case QCOW2_EXT_MAGIC_END: 128 return 0; 129 130 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 131 if (ext.len >= sizeof(bs->backing_format)) { 132 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 133 " too large (>=%zu)", ext.len, 134 sizeof(bs->backing_format)); 135 return 2; 136 } 137 ret = bdrv_pread(bs->file->bs, offset, bs->backing_format, ext.len); 138 if (ret < 0) { 139 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 140 "Could not read format name"); 141 return 3; 142 } 143 bs->backing_format[ext.len] = '\0'; 144 s->image_backing_format = g_strdup(bs->backing_format); 145 #ifdef DEBUG_EXT 146 printf("Qcow2: Got format extension %s\n", bs->backing_format); 147 #endif 148 break; 149 150 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 151 if (p_feature_table != NULL) { 152 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 153 ret = bdrv_pread(bs->file->bs, offset , feature_table, ext.len); 154 if (ret < 0) { 155 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 156 "Could not read table"); 157 return ret; 158 } 159 160 *p_feature_table = feature_table; 161 } 162 break; 163 164 default: 165 /* unknown magic - save it in case we need to rewrite the header */ 166 { 167 Qcow2UnknownHeaderExtension *uext; 168 169 uext = g_malloc0(sizeof(*uext) + ext.len); 170 uext->magic = ext.magic; 171 uext->len = ext.len; 172 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 173 174 ret = bdrv_pread(bs->file->bs, offset , uext->data, uext->len); 175 if (ret < 0) { 176 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 177 "Could not read data"); 178 return ret; 179 } 180 } 181 break; 182 } 183 184 offset += ((ext.len + 7) & ~7); 185 } 186 187 return 0; 188 } 189 190 static void cleanup_unknown_header_ext(BlockDriverState *bs) 191 { 192 BDRVQcow2State *s = bs->opaque; 193 Qcow2UnknownHeaderExtension *uext, *next; 194 195 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 196 QLIST_REMOVE(uext, next); 197 g_free(uext); 198 } 199 } 200 201 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 202 uint64_t mask) 203 { 204 char *features = g_strdup(""); 205 char *old; 206 207 while (table && table->name[0] != '\0') { 208 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 209 if (mask & (1ULL << table->bit)) { 210 old = features; 211 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 212 table->name); 213 g_free(old); 214 mask &= ~(1ULL << table->bit); 215 } 216 } 217 table++; 218 } 219 220 if (mask) { 221 old = features; 222 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 223 old, *old ? ", " : "", mask); 224 g_free(old); 225 } 226 227 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 228 g_free(features); 229 } 230 231 /* 232 * Sets the dirty bit and flushes afterwards if necessary. 233 * 234 * The incompatible_features bit is only set if the image file header was 235 * updated successfully. Therefore it is not required to check the return 236 * value of this function. 237 */ 238 int qcow2_mark_dirty(BlockDriverState *bs) 239 { 240 BDRVQcow2State *s = bs->opaque; 241 uint64_t val; 242 int ret; 243 244 assert(s->qcow_version >= 3); 245 246 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 247 return 0; /* already dirty */ 248 } 249 250 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 251 ret = bdrv_pwrite(bs->file->bs, offsetof(QCowHeader, incompatible_features), 252 &val, sizeof(val)); 253 if (ret < 0) { 254 return ret; 255 } 256 ret = bdrv_flush(bs->file->bs); 257 if (ret < 0) { 258 return ret; 259 } 260 261 /* Only treat image as dirty if the header was updated successfully */ 262 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 263 return 0; 264 } 265 266 /* 267 * Clears the dirty bit and flushes before if necessary. Only call this 268 * function when there are no pending requests, it does not guard against 269 * concurrent requests dirtying the image. 270 */ 271 static int qcow2_mark_clean(BlockDriverState *bs) 272 { 273 BDRVQcow2State *s = bs->opaque; 274 275 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 276 int ret; 277 278 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 279 280 ret = bdrv_flush(bs); 281 if (ret < 0) { 282 return ret; 283 } 284 285 return qcow2_update_header(bs); 286 } 287 return 0; 288 } 289 290 /* 291 * Marks the image as corrupt. 292 */ 293 int qcow2_mark_corrupt(BlockDriverState *bs) 294 { 295 BDRVQcow2State *s = bs->opaque; 296 297 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 298 return qcow2_update_header(bs); 299 } 300 301 /* 302 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 303 * before if necessary. 304 */ 305 int qcow2_mark_consistent(BlockDriverState *bs) 306 { 307 BDRVQcow2State *s = bs->opaque; 308 309 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 310 int ret = bdrv_flush(bs); 311 if (ret < 0) { 312 return ret; 313 } 314 315 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 316 return qcow2_update_header(bs); 317 } 318 return 0; 319 } 320 321 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 322 BdrvCheckMode fix) 323 { 324 int ret = qcow2_check_refcounts(bs, result, fix); 325 if (ret < 0) { 326 return ret; 327 } 328 329 if (fix && result->check_errors == 0 && result->corruptions == 0) { 330 ret = qcow2_mark_clean(bs); 331 if (ret < 0) { 332 return ret; 333 } 334 return qcow2_mark_consistent(bs); 335 } 336 return ret; 337 } 338 339 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 340 uint64_t entries, size_t entry_len) 341 { 342 BDRVQcow2State *s = bs->opaque; 343 uint64_t size; 344 345 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 346 * because values will be passed to qemu functions taking int64_t. */ 347 if (entries > INT64_MAX / entry_len) { 348 return -EINVAL; 349 } 350 351 size = entries * entry_len; 352 353 if (INT64_MAX - size < offset) { 354 return -EINVAL; 355 } 356 357 /* Tables must be cluster aligned */ 358 if (offset & (s->cluster_size - 1)) { 359 return -EINVAL; 360 } 361 362 return 0; 363 } 364 365 static QemuOptsList qcow2_runtime_opts = { 366 .name = "qcow2", 367 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 368 .desc = { 369 { 370 .name = QCOW2_OPT_LAZY_REFCOUNTS, 371 .type = QEMU_OPT_BOOL, 372 .help = "Postpone refcount updates", 373 }, 374 { 375 .name = QCOW2_OPT_DISCARD_REQUEST, 376 .type = QEMU_OPT_BOOL, 377 .help = "Pass guest discard requests to the layer below", 378 }, 379 { 380 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 381 .type = QEMU_OPT_BOOL, 382 .help = "Generate discard requests when snapshot related space " 383 "is freed", 384 }, 385 { 386 .name = QCOW2_OPT_DISCARD_OTHER, 387 .type = QEMU_OPT_BOOL, 388 .help = "Generate discard requests when other clusters are freed", 389 }, 390 { 391 .name = QCOW2_OPT_OVERLAP, 392 .type = QEMU_OPT_STRING, 393 .help = "Selects which overlap checks to perform from a range of " 394 "templates (none, constant, cached, all)", 395 }, 396 { 397 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 398 .type = QEMU_OPT_STRING, 399 .help = "Selects which overlap checks to perform from a range of " 400 "templates (none, constant, cached, all)", 401 }, 402 { 403 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 404 .type = QEMU_OPT_BOOL, 405 .help = "Check for unintended writes into the main qcow2 header", 406 }, 407 { 408 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 409 .type = QEMU_OPT_BOOL, 410 .help = "Check for unintended writes into the active L1 table", 411 }, 412 { 413 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 414 .type = QEMU_OPT_BOOL, 415 .help = "Check for unintended writes into an active L2 table", 416 }, 417 { 418 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 419 .type = QEMU_OPT_BOOL, 420 .help = "Check for unintended writes into the refcount table", 421 }, 422 { 423 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 424 .type = QEMU_OPT_BOOL, 425 .help = "Check for unintended writes into a refcount block", 426 }, 427 { 428 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 429 .type = QEMU_OPT_BOOL, 430 .help = "Check for unintended writes into the snapshot table", 431 }, 432 { 433 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 434 .type = QEMU_OPT_BOOL, 435 .help = "Check for unintended writes into an inactive L1 table", 436 }, 437 { 438 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 439 .type = QEMU_OPT_BOOL, 440 .help = "Check for unintended writes into an inactive L2 table", 441 }, 442 { 443 .name = QCOW2_OPT_CACHE_SIZE, 444 .type = QEMU_OPT_SIZE, 445 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 446 "cache size", 447 }, 448 { 449 .name = QCOW2_OPT_L2_CACHE_SIZE, 450 .type = QEMU_OPT_SIZE, 451 .help = "Maximum L2 table cache size", 452 }, 453 { 454 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 455 .type = QEMU_OPT_SIZE, 456 .help = "Maximum refcount block cache size", 457 }, 458 { 459 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 460 .type = QEMU_OPT_NUMBER, 461 .help = "Clean unused cache entries after this time (in seconds)", 462 }, 463 { /* end of list */ } 464 }, 465 }; 466 467 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 468 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 469 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 470 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 471 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 472 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 473 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 474 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 475 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 476 }; 477 478 static void cache_clean_timer_cb(void *opaque) 479 { 480 BlockDriverState *bs = opaque; 481 BDRVQcow2State *s = bs->opaque; 482 qcow2_cache_clean_unused(bs, s->l2_table_cache); 483 qcow2_cache_clean_unused(bs, s->refcount_block_cache); 484 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 485 (int64_t) s->cache_clean_interval * 1000); 486 } 487 488 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 489 { 490 BDRVQcow2State *s = bs->opaque; 491 if (s->cache_clean_interval > 0) { 492 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 493 SCALE_MS, cache_clean_timer_cb, 494 bs); 495 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 496 (int64_t) s->cache_clean_interval * 1000); 497 } 498 } 499 500 static void cache_clean_timer_del(BlockDriverState *bs) 501 { 502 BDRVQcow2State *s = bs->opaque; 503 if (s->cache_clean_timer) { 504 timer_del(s->cache_clean_timer); 505 timer_free(s->cache_clean_timer); 506 s->cache_clean_timer = NULL; 507 } 508 } 509 510 static void qcow2_detach_aio_context(BlockDriverState *bs) 511 { 512 cache_clean_timer_del(bs); 513 } 514 515 static void qcow2_attach_aio_context(BlockDriverState *bs, 516 AioContext *new_context) 517 { 518 cache_clean_timer_init(bs, new_context); 519 } 520 521 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 522 uint64_t *l2_cache_size, 523 uint64_t *refcount_cache_size, Error **errp) 524 { 525 BDRVQcow2State *s = bs->opaque; 526 uint64_t combined_cache_size; 527 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 528 529 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 530 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 531 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 532 533 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 534 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 535 *refcount_cache_size = qemu_opt_get_size(opts, 536 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 537 538 if (combined_cache_size_set) { 539 if (l2_cache_size_set && refcount_cache_size_set) { 540 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 541 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 542 "the same time"); 543 return; 544 } else if (*l2_cache_size > combined_cache_size) { 545 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 546 QCOW2_OPT_CACHE_SIZE); 547 return; 548 } else if (*refcount_cache_size > combined_cache_size) { 549 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 550 QCOW2_OPT_CACHE_SIZE); 551 return; 552 } 553 554 if (l2_cache_size_set) { 555 *refcount_cache_size = combined_cache_size - *l2_cache_size; 556 } else if (refcount_cache_size_set) { 557 *l2_cache_size = combined_cache_size - *refcount_cache_size; 558 } else { 559 *refcount_cache_size = combined_cache_size 560 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 561 *l2_cache_size = combined_cache_size - *refcount_cache_size; 562 } 563 } else { 564 if (!l2_cache_size_set && !refcount_cache_size_set) { 565 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 566 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 567 * s->cluster_size); 568 *refcount_cache_size = *l2_cache_size 569 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 570 } else if (!l2_cache_size_set) { 571 *l2_cache_size = *refcount_cache_size 572 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 573 } else if (!refcount_cache_size_set) { 574 *refcount_cache_size = *l2_cache_size 575 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 576 } 577 } 578 } 579 580 typedef struct Qcow2ReopenState { 581 Qcow2Cache *l2_table_cache; 582 Qcow2Cache *refcount_block_cache; 583 bool use_lazy_refcounts; 584 int overlap_check; 585 bool discard_passthrough[QCOW2_DISCARD_MAX]; 586 uint64_t cache_clean_interval; 587 } Qcow2ReopenState; 588 589 static int qcow2_update_options_prepare(BlockDriverState *bs, 590 Qcow2ReopenState *r, 591 QDict *options, int flags, 592 Error **errp) 593 { 594 BDRVQcow2State *s = bs->opaque; 595 QemuOpts *opts = NULL; 596 const char *opt_overlap_check, *opt_overlap_check_template; 597 int overlap_check_template = 0; 598 uint64_t l2_cache_size, refcount_cache_size; 599 int i; 600 Error *local_err = NULL; 601 int ret; 602 603 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 604 qemu_opts_absorb_qdict(opts, options, &local_err); 605 if (local_err) { 606 error_propagate(errp, local_err); 607 ret = -EINVAL; 608 goto fail; 609 } 610 611 /* get L2 table/refcount block cache size from command line options */ 612 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 613 &local_err); 614 if (local_err) { 615 error_propagate(errp, local_err); 616 ret = -EINVAL; 617 goto fail; 618 } 619 620 l2_cache_size /= s->cluster_size; 621 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 622 l2_cache_size = MIN_L2_CACHE_SIZE; 623 } 624 if (l2_cache_size > INT_MAX) { 625 error_setg(errp, "L2 cache size too big"); 626 ret = -EINVAL; 627 goto fail; 628 } 629 630 refcount_cache_size /= s->cluster_size; 631 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 632 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 633 } 634 if (refcount_cache_size > INT_MAX) { 635 error_setg(errp, "Refcount cache size too big"); 636 ret = -EINVAL; 637 goto fail; 638 } 639 640 /* alloc new L2 table/refcount block cache, flush old one */ 641 if (s->l2_table_cache) { 642 ret = qcow2_cache_flush(bs, s->l2_table_cache); 643 if (ret) { 644 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 645 goto fail; 646 } 647 } 648 649 if (s->refcount_block_cache) { 650 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 651 if (ret) { 652 error_setg_errno(errp, -ret, 653 "Failed to flush the refcount block cache"); 654 goto fail; 655 } 656 } 657 658 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 659 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 660 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 661 error_setg(errp, "Could not allocate metadata caches"); 662 ret = -ENOMEM; 663 goto fail; 664 } 665 666 /* New interval for cache cleanup timer */ 667 r->cache_clean_interval = 668 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 669 s->cache_clean_interval); 670 if (r->cache_clean_interval > UINT_MAX) { 671 error_setg(errp, "Cache clean interval too big"); 672 ret = -EINVAL; 673 goto fail; 674 } 675 676 /* lazy-refcounts; flush if going from enabled to disabled */ 677 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 678 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 679 if (r->use_lazy_refcounts && s->qcow_version < 3) { 680 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 681 "qemu 1.1 compatibility level"); 682 ret = -EINVAL; 683 goto fail; 684 } 685 686 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 687 ret = qcow2_mark_clean(bs); 688 if (ret < 0) { 689 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 690 goto fail; 691 } 692 } 693 694 /* Overlap check options */ 695 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 696 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 697 if (opt_overlap_check_template && opt_overlap_check && 698 strcmp(opt_overlap_check_template, opt_overlap_check)) 699 { 700 error_setg(errp, "Conflicting values for qcow2 options '" 701 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 702 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 703 ret = -EINVAL; 704 goto fail; 705 } 706 if (!opt_overlap_check) { 707 opt_overlap_check = opt_overlap_check_template ?: "cached"; 708 } 709 710 if (!strcmp(opt_overlap_check, "none")) { 711 overlap_check_template = 0; 712 } else if (!strcmp(opt_overlap_check, "constant")) { 713 overlap_check_template = QCOW2_OL_CONSTANT; 714 } else if (!strcmp(opt_overlap_check, "cached")) { 715 overlap_check_template = QCOW2_OL_CACHED; 716 } else if (!strcmp(opt_overlap_check, "all")) { 717 overlap_check_template = QCOW2_OL_ALL; 718 } else { 719 error_setg(errp, "Unsupported value '%s' for qcow2 option " 720 "'overlap-check'. Allowed are any of the following: " 721 "none, constant, cached, all", opt_overlap_check); 722 ret = -EINVAL; 723 goto fail; 724 } 725 726 r->overlap_check = 0; 727 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 728 /* overlap-check defines a template bitmask, but every flag may be 729 * overwritten through the associated boolean option */ 730 r->overlap_check |= 731 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 732 overlap_check_template & (1 << i)) << i; 733 } 734 735 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 736 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 737 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 738 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 739 flags & BDRV_O_UNMAP); 740 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 741 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 742 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 743 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 744 745 ret = 0; 746 fail: 747 qemu_opts_del(opts); 748 opts = NULL; 749 return ret; 750 } 751 752 static void qcow2_update_options_commit(BlockDriverState *bs, 753 Qcow2ReopenState *r) 754 { 755 BDRVQcow2State *s = bs->opaque; 756 int i; 757 758 if (s->l2_table_cache) { 759 qcow2_cache_destroy(bs, s->l2_table_cache); 760 } 761 if (s->refcount_block_cache) { 762 qcow2_cache_destroy(bs, s->refcount_block_cache); 763 } 764 s->l2_table_cache = r->l2_table_cache; 765 s->refcount_block_cache = r->refcount_block_cache; 766 767 s->overlap_check = r->overlap_check; 768 s->use_lazy_refcounts = r->use_lazy_refcounts; 769 770 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 771 s->discard_passthrough[i] = r->discard_passthrough[i]; 772 } 773 774 if (s->cache_clean_interval != r->cache_clean_interval) { 775 cache_clean_timer_del(bs); 776 s->cache_clean_interval = r->cache_clean_interval; 777 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 778 } 779 } 780 781 static void qcow2_update_options_abort(BlockDriverState *bs, 782 Qcow2ReopenState *r) 783 { 784 if (r->l2_table_cache) { 785 qcow2_cache_destroy(bs, r->l2_table_cache); 786 } 787 if (r->refcount_block_cache) { 788 qcow2_cache_destroy(bs, r->refcount_block_cache); 789 } 790 } 791 792 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 793 int flags, Error **errp) 794 { 795 Qcow2ReopenState r = {}; 796 int ret; 797 798 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 799 if (ret >= 0) { 800 qcow2_update_options_commit(bs, &r); 801 } else { 802 qcow2_update_options_abort(bs, &r); 803 } 804 805 return ret; 806 } 807 808 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 809 Error **errp) 810 { 811 BDRVQcow2State *s = bs->opaque; 812 unsigned int len, i; 813 int ret = 0; 814 QCowHeader header; 815 Error *local_err = NULL; 816 uint64_t ext_end; 817 uint64_t l1_vm_state_index; 818 819 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 820 if (ret < 0) { 821 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 822 goto fail; 823 } 824 be32_to_cpus(&header.magic); 825 be32_to_cpus(&header.version); 826 be64_to_cpus(&header.backing_file_offset); 827 be32_to_cpus(&header.backing_file_size); 828 be64_to_cpus(&header.size); 829 be32_to_cpus(&header.cluster_bits); 830 be32_to_cpus(&header.crypt_method); 831 be64_to_cpus(&header.l1_table_offset); 832 be32_to_cpus(&header.l1_size); 833 be64_to_cpus(&header.refcount_table_offset); 834 be32_to_cpus(&header.refcount_table_clusters); 835 be64_to_cpus(&header.snapshots_offset); 836 be32_to_cpus(&header.nb_snapshots); 837 838 if (header.magic != QCOW_MAGIC) { 839 error_setg(errp, "Image is not in qcow2 format"); 840 ret = -EINVAL; 841 goto fail; 842 } 843 if (header.version < 2 || header.version > 3) { 844 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 845 ret = -ENOTSUP; 846 goto fail; 847 } 848 849 s->qcow_version = header.version; 850 851 /* Initialise cluster size */ 852 if (header.cluster_bits < MIN_CLUSTER_BITS || 853 header.cluster_bits > MAX_CLUSTER_BITS) { 854 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 855 header.cluster_bits); 856 ret = -EINVAL; 857 goto fail; 858 } 859 860 s->cluster_bits = header.cluster_bits; 861 s->cluster_size = 1 << s->cluster_bits; 862 s->cluster_sectors = 1 << (s->cluster_bits - 9); 863 864 /* Initialise version 3 header fields */ 865 if (header.version == 2) { 866 header.incompatible_features = 0; 867 header.compatible_features = 0; 868 header.autoclear_features = 0; 869 header.refcount_order = 4; 870 header.header_length = 72; 871 } else { 872 be64_to_cpus(&header.incompatible_features); 873 be64_to_cpus(&header.compatible_features); 874 be64_to_cpus(&header.autoclear_features); 875 be32_to_cpus(&header.refcount_order); 876 be32_to_cpus(&header.header_length); 877 878 if (header.header_length < 104) { 879 error_setg(errp, "qcow2 header too short"); 880 ret = -EINVAL; 881 goto fail; 882 } 883 } 884 885 if (header.header_length > s->cluster_size) { 886 error_setg(errp, "qcow2 header exceeds cluster size"); 887 ret = -EINVAL; 888 goto fail; 889 } 890 891 if (header.header_length > sizeof(header)) { 892 s->unknown_header_fields_size = header.header_length - sizeof(header); 893 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 894 ret = bdrv_pread(bs->file->bs, sizeof(header), s->unknown_header_fields, 895 s->unknown_header_fields_size); 896 if (ret < 0) { 897 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 898 "fields"); 899 goto fail; 900 } 901 } 902 903 if (header.backing_file_offset > s->cluster_size) { 904 error_setg(errp, "Invalid backing file offset"); 905 ret = -EINVAL; 906 goto fail; 907 } 908 909 if (header.backing_file_offset) { 910 ext_end = header.backing_file_offset; 911 } else { 912 ext_end = 1 << header.cluster_bits; 913 } 914 915 /* Handle feature bits */ 916 s->incompatible_features = header.incompatible_features; 917 s->compatible_features = header.compatible_features; 918 s->autoclear_features = header.autoclear_features; 919 920 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 921 void *feature_table = NULL; 922 qcow2_read_extensions(bs, header.header_length, ext_end, 923 &feature_table, NULL); 924 report_unsupported_feature(errp, feature_table, 925 s->incompatible_features & 926 ~QCOW2_INCOMPAT_MASK); 927 ret = -ENOTSUP; 928 g_free(feature_table); 929 goto fail; 930 } 931 932 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 933 /* Corrupt images may not be written to unless they are being repaired 934 */ 935 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 936 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 937 "read/write"); 938 ret = -EACCES; 939 goto fail; 940 } 941 } 942 943 /* Check support for various header values */ 944 if (header.refcount_order > 6) { 945 error_setg(errp, "Reference count entry width too large; may not " 946 "exceed 64 bits"); 947 ret = -EINVAL; 948 goto fail; 949 } 950 s->refcount_order = header.refcount_order; 951 s->refcount_bits = 1 << s->refcount_order; 952 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 953 s->refcount_max += s->refcount_max - 1; 954 955 if (header.crypt_method > QCOW_CRYPT_AES) { 956 error_setg(errp, "Unsupported encryption method: %" PRIu32, 957 header.crypt_method); 958 ret = -EINVAL; 959 goto fail; 960 } 961 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 962 error_setg(errp, "AES cipher not available"); 963 ret = -EINVAL; 964 goto fail; 965 } 966 s->crypt_method_header = header.crypt_method; 967 if (s->crypt_method_header) { 968 bs->encrypted = 1; 969 } 970 971 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 972 s->l2_size = 1 << s->l2_bits; 973 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 974 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 975 s->refcount_block_size = 1 << s->refcount_block_bits; 976 bs->total_sectors = header.size / 512; 977 s->csize_shift = (62 - (s->cluster_bits - 8)); 978 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 979 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 980 981 s->refcount_table_offset = header.refcount_table_offset; 982 s->refcount_table_size = 983 header.refcount_table_clusters << (s->cluster_bits - 3); 984 985 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 986 error_setg(errp, "Reference count table too large"); 987 ret = -EINVAL; 988 goto fail; 989 } 990 991 ret = validate_table_offset(bs, s->refcount_table_offset, 992 s->refcount_table_size, sizeof(uint64_t)); 993 if (ret < 0) { 994 error_setg(errp, "Invalid reference count table offset"); 995 goto fail; 996 } 997 998 /* Snapshot table offset/length */ 999 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1000 error_setg(errp, "Too many snapshots"); 1001 ret = -EINVAL; 1002 goto fail; 1003 } 1004 1005 ret = validate_table_offset(bs, header.snapshots_offset, 1006 header.nb_snapshots, 1007 sizeof(QCowSnapshotHeader)); 1008 if (ret < 0) { 1009 error_setg(errp, "Invalid snapshot table offset"); 1010 goto fail; 1011 } 1012 1013 /* read the level 1 table */ 1014 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1015 error_setg(errp, "Active L1 table too large"); 1016 ret = -EFBIG; 1017 goto fail; 1018 } 1019 s->l1_size = header.l1_size; 1020 1021 l1_vm_state_index = size_to_l1(s, header.size); 1022 if (l1_vm_state_index > INT_MAX) { 1023 error_setg(errp, "Image is too big"); 1024 ret = -EFBIG; 1025 goto fail; 1026 } 1027 s->l1_vm_state_index = l1_vm_state_index; 1028 1029 /* the L1 table must contain at least enough entries to put 1030 header.size bytes */ 1031 if (s->l1_size < s->l1_vm_state_index) { 1032 error_setg(errp, "L1 table is too small"); 1033 ret = -EINVAL; 1034 goto fail; 1035 } 1036 1037 ret = validate_table_offset(bs, header.l1_table_offset, 1038 header.l1_size, sizeof(uint64_t)); 1039 if (ret < 0) { 1040 error_setg(errp, "Invalid L1 table offset"); 1041 goto fail; 1042 } 1043 s->l1_table_offset = header.l1_table_offset; 1044 1045 1046 if (s->l1_size > 0) { 1047 s->l1_table = qemu_try_blockalign(bs->file->bs, 1048 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1049 if (s->l1_table == NULL) { 1050 error_setg(errp, "Could not allocate L1 table"); 1051 ret = -ENOMEM; 1052 goto fail; 1053 } 1054 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 1055 s->l1_size * sizeof(uint64_t)); 1056 if (ret < 0) { 1057 error_setg_errno(errp, -ret, "Could not read L1 table"); 1058 goto fail; 1059 } 1060 for(i = 0;i < s->l1_size; i++) { 1061 be64_to_cpus(&s->l1_table[i]); 1062 } 1063 } 1064 1065 /* Parse driver-specific options */ 1066 ret = qcow2_update_options(bs, options, flags, errp); 1067 if (ret < 0) { 1068 goto fail; 1069 } 1070 1071 s->cluster_cache = g_malloc(s->cluster_size); 1072 /* one more sector for decompressed data alignment */ 1073 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1074 * s->cluster_size + 512); 1075 if (s->cluster_data == NULL) { 1076 error_setg(errp, "Could not allocate temporary cluster buffer"); 1077 ret = -ENOMEM; 1078 goto fail; 1079 } 1080 1081 s->cluster_cache_offset = -1; 1082 s->flags = flags; 1083 1084 ret = qcow2_refcount_init(bs); 1085 if (ret != 0) { 1086 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1087 goto fail; 1088 } 1089 1090 QLIST_INIT(&s->cluster_allocs); 1091 QTAILQ_INIT(&s->discards); 1092 1093 /* read qcow2 extensions */ 1094 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1095 &local_err)) { 1096 error_propagate(errp, local_err); 1097 ret = -EINVAL; 1098 goto fail; 1099 } 1100 1101 /* read the backing file name */ 1102 if (header.backing_file_offset != 0) { 1103 len = header.backing_file_size; 1104 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1105 len >= sizeof(bs->backing_file)) { 1106 error_setg(errp, "Backing file name too long"); 1107 ret = -EINVAL; 1108 goto fail; 1109 } 1110 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 1111 bs->backing_file, len); 1112 if (ret < 0) { 1113 error_setg_errno(errp, -ret, "Could not read backing file name"); 1114 goto fail; 1115 } 1116 bs->backing_file[len] = '\0'; 1117 s->image_backing_file = g_strdup(bs->backing_file); 1118 } 1119 1120 /* Internal snapshots */ 1121 s->snapshots_offset = header.snapshots_offset; 1122 s->nb_snapshots = header.nb_snapshots; 1123 1124 ret = qcow2_read_snapshots(bs); 1125 if (ret < 0) { 1126 error_setg_errno(errp, -ret, "Could not read snapshots"); 1127 goto fail; 1128 } 1129 1130 /* Clear unknown autoclear feature bits */ 1131 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { 1132 s->autoclear_features = 0; 1133 ret = qcow2_update_header(bs); 1134 if (ret < 0) { 1135 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1136 goto fail; 1137 } 1138 } 1139 1140 /* Initialise locks */ 1141 qemu_co_mutex_init(&s->lock); 1142 1143 /* Repair image if dirty */ 1144 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1145 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1146 BdrvCheckResult result = {0}; 1147 1148 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1149 if (ret < 0) { 1150 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1151 goto fail; 1152 } 1153 } 1154 1155 #ifdef DEBUG_ALLOC 1156 { 1157 BdrvCheckResult result = {0}; 1158 qcow2_check_refcounts(bs, &result, 0); 1159 } 1160 #endif 1161 return ret; 1162 1163 fail: 1164 g_free(s->unknown_header_fields); 1165 cleanup_unknown_header_ext(bs); 1166 qcow2_free_snapshots(bs); 1167 qcow2_refcount_close(bs); 1168 qemu_vfree(s->l1_table); 1169 /* else pre-write overlap checks in cache_destroy may crash */ 1170 s->l1_table = NULL; 1171 cache_clean_timer_del(bs); 1172 if (s->l2_table_cache) { 1173 qcow2_cache_destroy(bs, s->l2_table_cache); 1174 } 1175 if (s->refcount_block_cache) { 1176 qcow2_cache_destroy(bs, s->refcount_block_cache); 1177 } 1178 g_free(s->cluster_cache); 1179 qemu_vfree(s->cluster_data); 1180 return ret; 1181 } 1182 1183 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1184 { 1185 BDRVQcow2State *s = bs->opaque; 1186 1187 bs->bl.write_zeroes_alignment = s->cluster_sectors; 1188 } 1189 1190 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1191 { 1192 BDRVQcow2State *s = bs->opaque; 1193 uint8_t keybuf[16]; 1194 int len, i; 1195 Error *err = NULL; 1196 1197 memset(keybuf, 0, 16); 1198 len = strlen(key); 1199 if (len > 16) 1200 len = 16; 1201 /* XXX: we could compress the chars to 7 bits to increase 1202 entropy */ 1203 for(i = 0;i < len;i++) { 1204 keybuf[i] = key[i]; 1205 } 1206 assert(bs->encrypted); 1207 1208 qcrypto_cipher_free(s->cipher); 1209 s->cipher = qcrypto_cipher_new( 1210 QCRYPTO_CIPHER_ALG_AES_128, 1211 QCRYPTO_CIPHER_MODE_CBC, 1212 keybuf, G_N_ELEMENTS(keybuf), 1213 &err); 1214 1215 if (!s->cipher) { 1216 /* XXX would be nice if errors in this method could 1217 * be properly propagate to the caller. Would need 1218 * the bdrv_set_key() API signature to be fixed. */ 1219 error_free(err); 1220 return -1; 1221 } 1222 return 0; 1223 } 1224 1225 static int qcow2_reopen_prepare(BDRVReopenState *state, 1226 BlockReopenQueue *queue, Error **errp) 1227 { 1228 Qcow2ReopenState *r; 1229 int ret; 1230 1231 r = g_new0(Qcow2ReopenState, 1); 1232 state->opaque = r; 1233 1234 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1235 state->flags, errp); 1236 if (ret < 0) { 1237 goto fail; 1238 } 1239 1240 /* We need to write out any unwritten data if we reopen read-only. */ 1241 if ((state->flags & BDRV_O_RDWR) == 0) { 1242 ret = bdrv_flush(state->bs); 1243 if (ret < 0) { 1244 goto fail; 1245 } 1246 1247 ret = qcow2_mark_clean(state->bs); 1248 if (ret < 0) { 1249 goto fail; 1250 } 1251 } 1252 1253 return 0; 1254 1255 fail: 1256 qcow2_update_options_abort(state->bs, r); 1257 g_free(r); 1258 return ret; 1259 } 1260 1261 static void qcow2_reopen_commit(BDRVReopenState *state) 1262 { 1263 qcow2_update_options_commit(state->bs, state->opaque); 1264 g_free(state->opaque); 1265 } 1266 1267 static void qcow2_reopen_abort(BDRVReopenState *state) 1268 { 1269 qcow2_update_options_abort(state->bs, state->opaque); 1270 g_free(state->opaque); 1271 } 1272 1273 static void qcow2_join_options(QDict *options, QDict *old_options) 1274 { 1275 bool has_new_overlap_template = 1276 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1277 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1278 bool has_new_total_cache_size = 1279 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1280 bool has_all_cache_options; 1281 1282 /* New overlap template overrides all old overlap options */ 1283 if (has_new_overlap_template) { 1284 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1285 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1286 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1287 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1288 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1289 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1290 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1291 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1292 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1293 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1294 } 1295 1296 /* New total cache size overrides all old options */ 1297 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1298 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1299 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1300 } 1301 1302 qdict_join(options, old_options, false); 1303 1304 /* 1305 * If after merging all cache size options are set, an old total size is 1306 * overwritten. Do keep all options, however, if all three are new. The 1307 * resulting error message is what we want to happen. 1308 */ 1309 has_all_cache_options = 1310 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1311 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1312 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1313 1314 if (has_all_cache_options && !has_new_total_cache_size) { 1315 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1316 } 1317 } 1318 1319 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1320 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1321 { 1322 BDRVQcow2State *s = bs->opaque; 1323 uint64_t cluster_offset; 1324 int index_in_cluster, ret; 1325 int64_t status = 0; 1326 1327 *pnum = nb_sectors; 1328 qemu_co_mutex_lock(&s->lock); 1329 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); 1330 qemu_co_mutex_unlock(&s->lock); 1331 if (ret < 0) { 1332 return ret; 1333 } 1334 1335 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1336 !s->cipher) { 1337 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1338 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1339 *file = bs->file->bs; 1340 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1341 } 1342 if (ret == QCOW2_CLUSTER_ZERO) { 1343 status |= BDRV_BLOCK_ZERO; 1344 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1345 status |= BDRV_BLOCK_DATA; 1346 } 1347 return status; 1348 } 1349 1350 /* handle reading after the end of the backing file */ 1351 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1352 int64_t sector_num, int nb_sectors) 1353 { 1354 int n1; 1355 if ((sector_num + nb_sectors) <= bs->total_sectors) 1356 return nb_sectors; 1357 if (sector_num >= bs->total_sectors) 1358 n1 = 0; 1359 else 1360 n1 = bs->total_sectors - sector_num; 1361 1362 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1363 1364 return n1; 1365 } 1366 1367 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1368 int remaining_sectors, QEMUIOVector *qiov) 1369 { 1370 BDRVQcow2State *s = bs->opaque; 1371 int index_in_cluster, n1; 1372 int ret; 1373 int cur_nr_sectors; /* number of sectors in current iteration */ 1374 uint64_t cluster_offset = 0; 1375 uint64_t bytes_done = 0; 1376 QEMUIOVector hd_qiov; 1377 uint8_t *cluster_data = NULL; 1378 1379 qemu_iovec_init(&hd_qiov, qiov->niov); 1380 1381 qemu_co_mutex_lock(&s->lock); 1382 1383 while (remaining_sectors != 0) { 1384 1385 /* prepare next request */ 1386 cur_nr_sectors = remaining_sectors; 1387 if (s->cipher) { 1388 cur_nr_sectors = MIN(cur_nr_sectors, 1389 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1390 } 1391 1392 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1393 &cur_nr_sectors, &cluster_offset); 1394 if (ret < 0) { 1395 goto fail; 1396 } 1397 1398 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1399 1400 qemu_iovec_reset(&hd_qiov); 1401 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1402 cur_nr_sectors * 512); 1403 1404 switch (ret) { 1405 case QCOW2_CLUSTER_UNALLOCATED: 1406 1407 if (bs->backing) { 1408 /* read from the base image */ 1409 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1410 sector_num, cur_nr_sectors); 1411 if (n1 > 0) { 1412 QEMUIOVector local_qiov; 1413 1414 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1415 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1416 n1 * BDRV_SECTOR_SIZE); 1417 1418 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1419 qemu_co_mutex_unlock(&s->lock); 1420 ret = bdrv_co_readv(bs->backing->bs, sector_num, 1421 n1, &local_qiov); 1422 qemu_co_mutex_lock(&s->lock); 1423 1424 qemu_iovec_destroy(&local_qiov); 1425 1426 if (ret < 0) { 1427 goto fail; 1428 } 1429 } 1430 } else { 1431 /* Note: in this case, no need to wait */ 1432 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1433 } 1434 break; 1435 1436 case QCOW2_CLUSTER_ZERO: 1437 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1438 break; 1439 1440 case QCOW2_CLUSTER_COMPRESSED: 1441 /* add AIO support for compressed blocks ? */ 1442 ret = qcow2_decompress_cluster(bs, cluster_offset); 1443 if (ret < 0) { 1444 goto fail; 1445 } 1446 1447 qemu_iovec_from_buf(&hd_qiov, 0, 1448 s->cluster_cache + index_in_cluster * 512, 1449 512 * cur_nr_sectors); 1450 break; 1451 1452 case QCOW2_CLUSTER_NORMAL: 1453 if ((cluster_offset & 511) != 0) { 1454 ret = -EIO; 1455 goto fail; 1456 } 1457 1458 if (bs->encrypted) { 1459 assert(s->cipher); 1460 1461 /* 1462 * For encrypted images, read everything into a temporary 1463 * contiguous buffer on which the AES functions can work. 1464 */ 1465 if (!cluster_data) { 1466 cluster_data = 1467 qemu_try_blockalign(bs->file->bs, 1468 QCOW_MAX_CRYPT_CLUSTERS 1469 * s->cluster_size); 1470 if (cluster_data == NULL) { 1471 ret = -ENOMEM; 1472 goto fail; 1473 } 1474 } 1475 1476 assert(cur_nr_sectors <= 1477 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1478 qemu_iovec_reset(&hd_qiov); 1479 qemu_iovec_add(&hd_qiov, cluster_data, 1480 512 * cur_nr_sectors); 1481 } 1482 1483 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1484 qemu_co_mutex_unlock(&s->lock); 1485 ret = bdrv_co_readv(bs->file->bs, 1486 (cluster_offset >> 9) + index_in_cluster, 1487 cur_nr_sectors, &hd_qiov); 1488 qemu_co_mutex_lock(&s->lock); 1489 if (ret < 0) { 1490 goto fail; 1491 } 1492 if (bs->encrypted) { 1493 assert(s->cipher); 1494 Error *err = NULL; 1495 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1496 cluster_data, cur_nr_sectors, false, 1497 &err) < 0) { 1498 error_free(err); 1499 ret = -EIO; 1500 goto fail; 1501 } 1502 qemu_iovec_from_buf(qiov, bytes_done, 1503 cluster_data, 512 * cur_nr_sectors); 1504 } 1505 break; 1506 1507 default: 1508 g_assert_not_reached(); 1509 ret = -EIO; 1510 goto fail; 1511 } 1512 1513 remaining_sectors -= cur_nr_sectors; 1514 sector_num += cur_nr_sectors; 1515 bytes_done += cur_nr_sectors * 512; 1516 } 1517 ret = 0; 1518 1519 fail: 1520 qemu_co_mutex_unlock(&s->lock); 1521 1522 qemu_iovec_destroy(&hd_qiov); 1523 qemu_vfree(cluster_data); 1524 1525 return ret; 1526 } 1527 1528 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1529 int64_t sector_num, 1530 int remaining_sectors, 1531 QEMUIOVector *qiov) 1532 { 1533 BDRVQcow2State *s = bs->opaque; 1534 int index_in_cluster; 1535 int ret; 1536 int cur_nr_sectors; /* number of sectors in current iteration */ 1537 uint64_t cluster_offset; 1538 QEMUIOVector hd_qiov; 1539 uint64_t bytes_done = 0; 1540 uint8_t *cluster_data = NULL; 1541 QCowL2Meta *l2meta = NULL; 1542 1543 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1544 remaining_sectors); 1545 1546 qemu_iovec_init(&hd_qiov, qiov->niov); 1547 1548 s->cluster_cache_offset = -1; /* disable compressed cache */ 1549 1550 qemu_co_mutex_lock(&s->lock); 1551 1552 while (remaining_sectors != 0) { 1553 1554 l2meta = NULL; 1555 1556 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1557 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1558 cur_nr_sectors = remaining_sectors; 1559 if (bs->encrypted && 1560 cur_nr_sectors > 1561 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1562 cur_nr_sectors = 1563 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1564 } 1565 1566 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1567 &cur_nr_sectors, &cluster_offset, &l2meta); 1568 if (ret < 0) { 1569 goto fail; 1570 } 1571 1572 assert((cluster_offset & 511) == 0); 1573 1574 qemu_iovec_reset(&hd_qiov); 1575 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1576 cur_nr_sectors * 512); 1577 1578 if (bs->encrypted) { 1579 Error *err = NULL; 1580 assert(s->cipher); 1581 if (!cluster_data) { 1582 cluster_data = qemu_try_blockalign(bs->file->bs, 1583 QCOW_MAX_CRYPT_CLUSTERS 1584 * s->cluster_size); 1585 if (cluster_data == NULL) { 1586 ret = -ENOMEM; 1587 goto fail; 1588 } 1589 } 1590 1591 assert(hd_qiov.size <= 1592 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1593 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1594 1595 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1596 cluster_data, cur_nr_sectors, 1597 true, &err) < 0) { 1598 error_free(err); 1599 ret = -EIO; 1600 goto fail; 1601 } 1602 1603 qemu_iovec_reset(&hd_qiov); 1604 qemu_iovec_add(&hd_qiov, cluster_data, 1605 cur_nr_sectors * 512); 1606 } 1607 1608 ret = qcow2_pre_write_overlap_check(bs, 0, 1609 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1610 cur_nr_sectors * BDRV_SECTOR_SIZE); 1611 if (ret < 0) { 1612 goto fail; 1613 } 1614 1615 qemu_co_mutex_unlock(&s->lock); 1616 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1617 trace_qcow2_writev_data(qemu_coroutine_self(), 1618 (cluster_offset >> 9) + index_in_cluster); 1619 ret = bdrv_co_writev(bs->file->bs, 1620 (cluster_offset >> 9) + index_in_cluster, 1621 cur_nr_sectors, &hd_qiov); 1622 qemu_co_mutex_lock(&s->lock); 1623 if (ret < 0) { 1624 goto fail; 1625 } 1626 1627 while (l2meta != NULL) { 1628 QCowL2Meta *next; 1629 1630 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1631 if (ret < 0) { 1632 goto fail; 1633 } 1634 1635 /* Take the request off the list of running requests */ 1636 if (l2meta->nb_clusters != 0) { 1637 QLIST_REMOVE(l2meta, next_in_flight); 1638 } 1639 1640 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1641 1642 next = l2meta->next; 1643 g_free(l2meta); 1644 l2meta = next; 1645 } 1646 1647 remaining_sectors -= cur_nr_sectors; 1648 sector_num += cur_nr_sectors; 1649 bytes_done += cur_nr_sectors * 512; 1650 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1651 } 1652 ret = 0; 1653 1654 fail: 1655 qemu_co_mutex_unlock(&s->lock); 1656 1657 while (l2meta != NULL) { 1658 QCowL2Meta *next; 1659 1660 if (l2meta->nb_clusters != 0) { 1661 QLIST_REMOVE(l2meta, next_in_flight); 1662 } 1663 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1664 1665 next = l2meta->next; 1666 g_free(l2meta); 1667 l2meta = next; 1668 } 1669 1670 qemu_iovec_destroy(&hd_qiov); 1671 qemu_vfree(cluster_data); 1672 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1673 1674 return ret; 1675 } 1676 1677 static int qcow2_inactivate(BlockDriverState *bs) 1678 { 1679 BDRVQcow2State *s = bs->opaque; 1680 int ret, result = 0; 1681 1682 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1683 if (ret) { 1684 result = ret; 1685 error_report("Failed to flush the L2 table cache: %s", 1686 strerror(-ret)); 1687 } 1688 1689 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1690 if (ret) { 1691 result = ret; 1692 error_report("Failed to flush the refcount block cache: %s", 1693 strerror(-ret)); 1694 } 1695 1696 if (result == 0) { 1697 qcow2_mark_clean(bs); 1698 } 1699 1700 return result; 1701 } 1702 1703 static void qcow2_close(BlockDriverState *bs) 1704 { 1705 BDRVQcow2State *s = bs->opaque; 1706 qemu_vfree(s->l1_table); 1707 /* else pre-write overlap checks in cache_destroy may crash */ 1708 s->l1_table = NULL; 1709 1710 if (!(s->flags & BDRV_O_INACTIVE)) { 1711 qcow2_inactivate(bs); 1712 } 1713 1714 cache_clean_timer_del(bs); 1715 qcow2_cache_destroy(bs, s->l2_table_cache); 1716 qcow2_cache_destroy(bs, s->refcount_block_cache); 1717 1718 qcrypto_cipher_free(s->cipher); 1719 s->cipher = NULL; 1720 1721 g_free(s->unknown_header_fields); 1722 cleanup_unknown_header_ext(bs); 1723 1724 g_free(s->image_backing_file); 1725 g_free(s->image_backing_format); 1726 1727 g_free(s->cluster_cache); 1728 qemu_vfree(s->cluster_data); 1729 qcow2_refcount_close(bs); 1730 qcow2_free_snapshots(bs); 1731 } 1732 1733 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1734 { 1735 BDRVQcow2State *s = bs->opaque; 1736 int flags = s->flags; 1737 QCryptoCipher *cipher = NULL; 1738 QDict *options; 1739 Error *local_err = NULL; 1740 int ret; 1741 1742 /* 1743 * Backing files are read-only which makes all of their metadata immutable, 1744 * that means we don't have to worry about reopening them here. 1745 */ 1746 1747 cipher = s->cipher; 1748 s->cipher = NULL; 1749 1750 qcow2_close(bs); 1751 1752 bdrv_invalidate_cache(bs->file->bs, &local_err); 1753 if (local_err) { 1754 error_propagate(errp, local_err); 1755 bs->drv = NULL; 1756 return; 1757 } 1758 1759 memset(s, 0, sizeof(BDRVQcow2State)); 1760 options = qdict_clone_shallow(bs->options); 1761 1762 flags &= ~BDRV_O_INACTIVE; 1763 ret = qcow2_open(bs, options, flags, &local_err); 1764 QDECREF(options); 1765 if (local_err) { 1766 error_propagate(errp, local_err); 1767 error_prepend(errp, "Could not reopen qcow2 layer: "); 1768 bs->drv = NULL; 1769 return; 1770 } else if (ret < 0) { 1771 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1772 bs->drv = NULL; 1773 return; 1774 } 1775 1776 s->cipher = cipher; 1777 } 1778 1779 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1780 size_t len, size_t buflen) 1781 { 1782 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1783 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1784 1785 if (buflen < ext_len) { 1786 return -ENOSPC; 1787 } 1788 1789 *ext_backing_fmt = (QCowExtension) { 1790 .magic = cpu_to_be32(magic), 1791 .len = cpu_to_be32(len), 1792 }; 1793 memcpy(buf + sizeof(QCowExtension), s, len); 1794 1795 return ext_len; 1796 } 1797 1798 /* 1799 * Updates the qcow2 header, including the variable length parts of it, i.e. 1800 * the backing file name and all extensions. qcow2 was not designed to allow 1801 * such changes, so if we run out of space (we can only use the first cluster) 1802 * this function may fail. 1803 * 1804 * Returns 0 on success, -errno in error cases. 1805 */ 1806 int qcow2_update_header(BlockDriverState *bs) 1807 { 1808 BDRVQcow2State *s = bs->opaque; 1809 QCowHeader *header; 1810 char *buf; 1811 size_t buflen = s->cluster_size; 1812 int ret; 1813 uint64_t total_size; 1814 uint32_t refcount_table_clusters; 1815 size_t header_length; 1816 Qcow2UnknownHeaderExtension *uext; 1817 1818 buf = qemu_blockalign(bs, buflen); 1819 1820 /* Header structure */ 1821 header = (QCowHeader*) buf; 1822 1823 if (buflen < sizeof(*header)) { 1824 ret = -ENOSPC; 1825 goto fail; 1826 } 1827 1828 header_length = sizeof(*header) + s->unknown_header_fields_size; 1829 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1830 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1831 1832 *header = (QCowHeader) { 1833 /* Version 2 fields */ 1834 .magic = cpu_to_be32(QCOW_MAGIC), 1835 .version = cpu_to_be32(s->qcow_version), 1836 .backing_file_offset = 0, 1837 .backing_file_size = 0, 1838 .cluster_bits = cpu_to_be32(s->cluster_bits), 1839 .size = cpu_to_be64(total_size), 1840 .crypt_method = cpu_to_be32(s->crypt_method_header), 1841 .l1_size = cpu_to_be32(s->l1_size), 1842 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1843 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1844 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1845 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1846 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1847 1848 /* Version 3 fields */ 1849 .incompatible_features = cpu_to_be64(s->incompatible_features), 1850 .compatible_features = cpu_to_be64(s->compatible_features), 1851 .autoclear_features = cpu_to_be64(s->autoclear_features), 1852 .refcount_order = cpu_to_be32(s->refcount_order), 1853 .header_length = cpu_to_be32(header_length), 1854 }; 1855 1856 /* For older versions, write a shorter header */ 1857 switch (s->qcow_version) { 1858 case 2: 1859 ret = offsetof(QCowHeader, incompatible_features); 1860 break; 1861 case 3: 1862 ret = sizeof(*header); 1863 break; 1864 default: 1865 ret = -EINVAL; 1866 goto fail; 1867 } 1868 1869 buf += ret; 1870 buflen -= ret; 1871 memset(buf, 0, buflen); 1872 1873 /* Preserve any unknown field in the header */ 1874 if (s->unknown_header_fields_size) { 1875 if (buflen < s->unknown_header_fields_size) { 1876 ret = -ENOSPC; 1877 goto fail; 1878 } 1879 1880 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1881 buf += s->unknown_header_fields_size; 1882 buflen -= s->unknown_header_fields_size; 1883 } 1884 1885 /* Backing file format header extension */ 1886 if (s->image_backing_format) { 1887 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1888 s->image_backing_format, 1889 strlen(s->image_backing_format), 1890 buflen); 1891 if (ret < 0) { 1892 goto fail; 1893 } 1894 1895 buf += ret; 1896 buflen -= ret; 1897 } 1898 1899 /* Feature table */ 1900 if (s->qcow_version >= 3) { 1901 Qcow2Feature features[] = { 1902 { 1903 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1904 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1905 .name = "dirty bit", 1906 }, 1907 { 1908 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1909 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1910 .name = "corrupt bit", 1911 }, 1912 { 1913 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1914 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1915 .name = "lazy refcounts", 1916 }, 1917 }; 1918 1919 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1920 features, sizeof(features), buflen); 1921 if (ret < 0) { 1922 goto fail; 1923 } 1924 buf += ret; 1925 buflen -= ret; 1926 } 1927 1928 /* Keep unknown header extensions */ 1929 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1930 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1931 if (ret < 0) { 1932 goto fail; 1933 } 1934 1935 buf += ret; 1936 buflen -= ret; 1937 } 1938 1939 /* End of header extensions */ 1940 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1941 if (ret < 0) { 1942 goto fail; 1943 } 1944 1945 buf += ret; 1946 buflen -= ret; 1947 1948 /* Backing file name */ 1949 if (s->image_backing_file) { 1950 size_t backing_file_len = strlen(s->image_backing_file); 1951 1952 if (buflen < backing_file_len) { 1953 ret = -ENOSPC; 1954 goto fail; 1955 } 1956 1957 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1958 strncpy(buf, s->image_backing_file, buflen); 1959 1960 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1961 header->backing_file_size = cpu_to_be32(backing_file_len); 1962 } 1963 1964 /* Write the new header */ 1965 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size); 1966 if (ret < 0) { 1967 goto fail; 1968 } 1969 1970 ret = 0; 1971 fail: 1972 qemu_vfree(header); 1973 return ret; 1974 } 1975 1976 static int qcow2_change_backing_file(BlockDriverState *bs, 1977 const char *backing_file, const char *backing_fmt) 1978 { 1979 BDRVQcow2State *s = bs->opaque; 1980 1981 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1982 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1983 1984 g_free(s->image_backing_file); 1985 g_free(s->image_backing_format); 1986 1987 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 1988 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 1989 1990 return qcow2_update_header(bs); 1991 } 1992 1993 static int preallocate(BlockDriverState *bs) 1994 { 1995 uint64_t nb_sectors; 1996 uint64_t offset; 1997 uint64_t host_offset = 0; 1998 int num; 1999 int ret; 2000 QCowL2Meta *meta; 2001 2002 nb_sectors = bdrv_nb_sectors(bs); 2003 offset = 0; 2004 2005 while (nb_sectors) { 2006 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 2007 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 2008 &host_offset, &meta); 2009 if (ret < 0) { 2010 return ret; 2011 } 2012 2013 while (meta) { 2014 QCowL2Meta *next = meta->next; 2015 2016 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2017 if (ret < 0) { 2018 qcow2_free_any_clusters(bs, meta->alloc_offset, 2019 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2020 return ret; 2021 } 2022 2023 /* There are no dependent requests, but we need to remove our 2024 * request from the list of in-flight requests */ 2025 QLIST_REMOVE(meta, next_in_flight); 2026 2027 g_free(meta); 2028 meta = next; 2029 } 2030 2031 /* TODO Preallocate data if requested */ 2032 2033 nb_sectors -= num; 2034 offset += num << BDRV_SECTOR_BITS; 2035 } 2036 2037 /* 2038 * It is expected that the image file is large enough to actually contain 2039 * all of the allocated clusters (otherwise we get failing reads after 2040 * EOF). Extend the image to the last allocated sector. 2041 */ 2042 if (host_offset != 0) { 2043 uint8_t buf[BDRV_SECTOR_SIZE]; 2044 memset(buf, 0, BDRV_SECTOR_SIZE); 2045 ret = bdrv_write(bs->file->bs, 2046 (host_offset >> BDRV_SECTOR_BITS) + num - 1, 2047 buf, 1); 2048 if (ret < 0) { 2049 return ret; 2050 } 2051 } 2052 2053 return 0; 2054 } 2055 2056 static int qcow2_create2(const char *filename, int64_t total_size, 2057 const char *backing_file, const char *backing_format, 2058 int flags, size_t cluster_size, PreallocMode prealloc, 2059 QemuOpts *opts, int version, int refcount_order, 2060 Error **errp) 2061 { 2062 int cluster_bits; 2063 QDict *options; 2064 2065 /* Calculate cluster_bits */ 2066 cluster_bits = ctz32(cluster_size); 2067 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2068 (1 << cluster_bits) != cluster_size) 2069 { 2070 error_setg(errp, "Cluster size must be a power of two between %d and " 2071 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2072 return -EINVAL; 2073 } 2074 2075 /* 2076 * Open the image file and write a minimal qcow2 header. 2077 * 2078 * We keep things simple and start with a zero-sized image. We also 2079 * do without refcount blocks or a L1 table for now. We'll fix the 2080 * inconsistency later. 2081 * 2082 * We do need a refcount table because growing the refcount table means 2083 * allocating two new refcount blocks - the seconds of which would be at 2084 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2085 * size for any qcow2 image. 2086 */ 2087 BlockBackend *blk; 2088 QCowHeader *header; 2089 uint64_t* refcount_table; 2090 Error *local_err = NULL; 2091 int ret; 2092 2093 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2094 /* Note: The following calculation does not need to be exact; if it is a 2095 * bit off, either some bytes will be "leaked" (which is fine) or we 2096 * will need to increase the file size by some bytes (which is fine, 2097 * too, as long as the bulk is allocated here). Therefore, using 2098 * floating point arithmetic is fine. */ 2099 int64_t meta_size = 0; 2100 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2101 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2102 int refblock_bits, refblock_size; 2103 /* refcount entry size in bytes */ 2104 double rces = (1 << refcount_order) / 8.; 2105 2106 /* see qcow2_open() */ 2107 refblock_bits = cluster_bits - (refcount_order - 3); 2108 refblock_size = 1 << refblock_bits; 2109 2110 /* header: 1 cluster */ 2111 meta_size += cluster_size; 2112 2113 /* total size of L2 tables */ 2114 nl2e = aligned_total_size / cluster_size; 2115 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2116 meta_size += nl2e * sizeof(uint64_t); 2117 2118 /* total size of L1 tables */ 2119 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2120 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2121 meta_size += nl1e * sizeof(uint64_t); 2122 2123 /* total size of refcount blocks 2124 * 2125 * note: every host cluster is reference-counted, including metadata 2126 * (even refcount blocks are recursively included). 2127 * Let: 2128 * a = total_size (this is the guest disk size) 2129 * m = meta size not including refcount blocks and refcount tables 2130 * c = cluster size 2131 * y1 = number of refcount blocks entries 2132 * y2 = meta size including everything 2133 * rces = refcount entry size in bytes 2134 * then, 2135 * y1 = (y2 + a)/c 2136 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2137 * we can get y1: 2138 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2139 */ 2140 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2141 / (cluster_size - rces - rces * sizeof(uint64_t) 2142 / cluster_size); 2143 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2144 2145 /* total size of refcount tables */ 2146 nreftablee = nrefblocke / refblock_size; 2147 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2148 meta_size += nreftablee * sizeof(uint64_t); 2149 2150 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2151 aligned_total_size + meta_size, &error_abort); 2152 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2153 &error_abort); 2154 } 2155 2156 ret = bdrv_create_file(filename, opts, &local_err); 2157 if (ret < 0) { 2158 error_propagate(errp, local_err); 2159 return ret; 2160 } 2161 2162 blk = blk_new_open(filename, NULL, NULL, 2163 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, 2164 &local_err); 2165 if (blk == NULL) { 2166 error_propagate(errp, local_err); 2167 return -EIO; 2168 } 2169 2170 blk_set_allow_write_beyond_eof(blk, true); 2171 2172 /* Write the header */ 2173 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2174 header = g_malloc0(cluster_size); 2175 *header = (QCowHeader) { 2176 .magic = cpu_to_be32(QCOW_MAGIC), 2177 .version = cpu_to_be32(version), 2178 .cluster_bits = cpu_to_be32(cluster_bits), 2179 .size = cpu_to_be64(0), 2180 .l1_table_offset = cpu_to_be64(0), 2181 .l1_size = cpu_to_be32(0), 2182 .refcount_table_offset = cpu_to_be64(cluster_size), 2183 .refcount_table_clusters = cpu_to_be32(1), 2184 .refcount_order = cpu_to_be32(refcount_order), 2185 .header_length = cpu_to_be32(sizeof(*header)), 2186 }; 2187 2188 if (flags & BLOCK_FLAG_ENCRYPT) { 2189 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2190 } else { 2191 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2192 } 2193 2194 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2195 header->compatible_features |= 2196 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2197 } 2198 2199 ret = blk_pwrite(blk, 0, header, cluster_size); 2200 g_free(header); 2201 if (ret < 0) { 2202 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2203 goto out; 2204 } 2205 2206 /* Write a refcount table with one refcount block */ 2207 refcount_table = g_malloc0(2 * cluster_size); 2208 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2209 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size); 2210 g_free(refcount_table); 2211 2212 if (ret < 0) { 2213 error_setg_errno(errp, -ret, "Could not write refcount table"); 2214 goto out; 2215 } 2216 2217 blk_unref(blk); 2218 blk = NULL; 2219 2220 /* 2221 * And now open the image and make it consistent first (i.e. increase the 2222 * refcount of the cluster that is occupied by the header and the refcount 2223 * table) 2224 */ 2225 options = qdict_new(); 2226 qdict_put(options, "driver", qstring_from_str("qcow2")); 2227 blk = blk_new_open(filename, NULL, options, 2228 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, 2229 &local_err); 2230 if (blk == NULL) { 2231 error_propagate(errp, local_err); 2232 ret = -EIO; 2233 goto out; 2234 } 2235 2236 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2237 if (ret < 0) { 2238 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2239 "header and refcount table"); 2240 goto out; 2241 2242 } else if (ret != 0) { 2243 error_report("Huh, first cluster in empty image is already in use?"); 2244 abort(); 2245 } 2246 2247 /* Create a full header (including things like feature table) */ 2248 ret = qcow2_update_header(blk_bs(blk)); 2249 if (ret < 0) { 2250 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2251 goto out; 2252 } 2253 2254 /* Okay, now that we have a valid image, let's give it the right size */ 2255 ret = blk_truncate(blk, total_size); 2256 if (ret < 0) { 2257 error_setg_errno(errp, -ret, "Could not resize image"); 2258 goto out; 2259 } 2260 2261 /* Want a backing file? There you go.*/ 2262 if (backing_file) { 2263 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2264 if (ret < 0) { 2265 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2266 "with format '%s'", backing_file, backing_format); 2267 goto out; 2268 } 2269 } 2270 2271 /* And if we're supposed to preallocate metadata, do that now */ 2272 if (prealloc != PREALLOC_MODE_OFF) { 2273 BDRVQcow2State *s = blk_bs(blk)->opaque; 2274 qemu_co_mutex_lock(&s->lock); 2275 ret = preallocate(blk_bs(blk)); 2276 qemu_co_mutex_unlock(&s->lock); 2277 if (ret < 0) { 2278 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2279 goto out; 2280 } 2281 } 2282 2283 blk_unref(blk); 2284 blk = NULL; 2285 2286 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2287 options = qdict_new(); 2288 qdict_put(options, "driver", qstring_from_str("qcow2")); 2289 blk = blk_new_open(filename, NULL, options, 2290 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, 2291 &local_err); 2292 if (blk == NULL) { 2293 error_propagate(errp, local_err); 2294 ret = -EIO; 2295 goto out; 2296 } 2297 2298 ret = 0; 2299 out: 2300 if (blk) { 2301 blk_unref(blk); 2302 } 2303 return ret; 2304 } 2305 2306 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2307 { 2308 char *backing_file = NULL; 2309 char *backing_fmt = NULL; 2310 char *buf = NULL; 2311 uint64_t size = 0; 2312 int flags = 0; 2313 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2314 PreallocMode prealloc; 2315 int version = 3; 2316 uint64_t refcount_bits = 16; 2317 int refcount_order; 2318 Error *local_err = NULL; 2319 int ret; 2320 2321 /* Read out options */ 2322 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2323 BDRV_SECTOR_SIZE); 2324 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2325 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2326 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2327 flags |= BLOCK_FLAG_ENCRYPT; 2328 } 2329 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2330 DEFAULT_CLUSTER_SIZE); 2331 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2332 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2333 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2334 &local_err); 2335 if (local_err) { 2336 error_propagate(errp, local_err); 2337 ret = -EINVAL; 2338 goto finish; 2339 } 2340 g_free(buf); 2341 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2342 if (!buf) { 2343 /* keep the default */ 2344 } else if (!strcmp(buf, "0.10")) { 2345 version = 2; 2346 } else if (!strcmp(buf, "1.1")) { 2347 version = 3; 2348 } else { 2349 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2350 ret = -EINVAL; 2351 goto finish; 2352 } 2353 2354 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2355 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2356 } 2357 2358 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2359 error_setg(errp, "Backing file and preallocation cannot be used at " 2360 "the same time"); 2361 ret = -EINVAL; 2362 goto finish; 2363 } 2364 2365 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2366 error_setg(errp, "Lazy refcounts only supported with compatibility " 2367 "level 1.1 and above (use compat=1.1 or greater)"); 2368 ret = -EINVAL; 2369 goto finish; 2370 } 2371 2372 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2373 refcount_bits); 2374 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2375 error_setg(errp, "Refcount width must be a power of two and may not " 2376 "exceed 64 bits"); 2377 ret = -EINVAL; 2378 goto finish; 2379 } 2380 2381 if (version < 3 && refcount_bits != 16) { 2382 error_setg(errp, "Different refcount widths than 16 bits require " 2383 "compatibility level 1.1 or above (use compat=1.1 or " 2384 "greater)"); 2385 ret = -EINVAL; 2386 goto finish; 2387 } 2388 2389 refcount_order = ctz32(refcount_bits); 2390 2391 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2392 cluster_size, prealloc, opts, version, refcount_order, 2393 &local_err); 2394 if (local_err) { 2395 error_propagate(errp, local_err); 2396 } 2397 2398 finish: 2399 g_free(backing_file); 2400 g_free(backing_fmt); 2401 g_free(buf); 2402 return ret; 2403 } 2404 2405 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2406 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2407 { 2408 int ret; 2409 BDRVQcow2State *s = bs->opaque; 2410 2411 /* Emulate misaligned zero writes */ 2412 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { 2413 return -ENOTSUP; 2414 } 2415 2416 /* Whatever is left can use real zero clusters */ 2417 qemu_co_mutex_lock(&s->lock); 2418 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2419 nb_sectors); 2420 qemu_co_mutex_unlock(&s->lock); 2421 2422 return ret; 2423 } 2424 2425 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2426 int64_t sector_num, int nb_sectors) 2427 { 2428 int ret; 2429 BDRVQcow2State *s = bs->opaque; 2430 2431 qemu_co_mutex_lock(&s->lock); 2432 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2433 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2434 qemu_co_mutex_unlock(&s->lock); 2435 return ret; 2436 } 2437 2438 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2439 { 2440 BDRVQcow2State *s = bs->opaque; 2441 int64_t new_l1_size; 2442 int ret; 2443 2444 if (offset & 511) { 2445 error_report("The new size must be a multiple of 512"); 2446 return -EINVAL; 2447 } 2448 2449 /* cannot proceed if image has snapshots */ 2450 if (s->nb_snapshots) { 2451 error_report("Can't resize an image which has snapshots"); 2452 return -ENOTSUP; 2453 } 2454 2455 /* shrinking is currently not supported */ 2456 if (offset < bs->total_sectors * 512) { 2457 error_report("qcow2 doesn't support shrinking images yet"); 2458 return -ENOTSUP; 2459 } 2460 2461 new_l1_size = size_to_l1(s, offset); 2462 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2463 if (ret < 0) { 2464 return ret; 2465 } 2466 2467 /* write updated header.size */ 2468 offset = cpu_to_be64(offset); 2469 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), 2470 &offset, sizeof(uint64_t)); 2471 if (ret < 0) { 2472 return ret; 2473 } 2474 2475 s->l1_vm_state_index = new_l1_size; 2476 return 0; 2477 } 2478 2479 /* XXX: put compressed sectors first, then all the cluster aligned 2480 tables to avoid losing bytes in alignment */ 2481 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2482 const uint8_t *buf, int nb_sectors) 2483 { 2484 BDRVQcow2State *s = bs->opaque; 2485 z_stream strm; 2486 int ret, out_len; 2487 uint8_t *out_buf; 2488 uint64_t cluster_offset; 2489 2490 if (nb_sectors == 0) { 2491 /* align end of file to a sector boundary to ease reading with 2492 sector based I/Os */ 2493 cluster_offset = bdrv_getlength(bs->file->bs); 2494 return bdrv_truncate(bs->file->bs, cluster_offset); 2495 } 2496 2497 if (nb_sectors != s->cluster_sectors) { 2498 ret = -EINVAL; 2499 2500 /* Zero-pad last write if image size is not cluster aligned */ 2501 if (sector_num + nb_sectors == bs->total_sectors && 2502 nb_sectors < s->cluster_sectors) { 2503 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2504 memset(pad_buf, 0, s->cluster_size); 2505 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2506 ret = qcow2_write_compressed(bs, sector_num, 2507 pad_buf, s->cluster_sectors); 2508 qemu_vfree(pad_buf); 2509 } 2510 return ret; 2511 } 2512 2513 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2514 2515 /* best compression, small window, no zlib header */ 2516 memset(&strm, 0, sizeof(strm)); 2517 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2518 Z_DEFLATED, -12, 2519 9, Z_DEFAULT_STRATEGY); 2520 if (ret != 0) { 2521 ret = -EINVAL; 2522 goto fail; 2523 } 2524 2525 strm.avail_in = s->cluster_size; 2526 strm.next_in = (uint8_t *)buf; 2527 strm.avail_out = s->cluster_size; 2528 strm.next_out = out_buf; 2529 2530 ret = deflate(&strm, Z_FINISH); 2531 if (ret != Z_STREAM_END && ret != Z_OK) { 2532 deflateEnd(&strm); 2533 ret = -EINVAL; 2534 goto fail; 2535 } 2536 out_len = strm.next_out - out_buf; 2537 2538 deflateEnd(&strm); 2539 2540 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2541 /* could not compress: write normal cluster */ 2542 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2543 if (ret < 0) { 2544 goto fail; 2545 } 2546 } else { 2547 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2548 sector_num << 9, out_len); 2549 if (!cluster_offset) { 2550 ret = -EIO; 2551 goto fail; 2552 } 2553 cluster_offset &= s->cluster_offset_mask; 2554 2555 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2556 if (ret < 0) { 2557 goto fail; 2558 } 2559 2560 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2561 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 2562 if (ret < 0) { 2563 goto fail; 2564 } 2565 } 2566 2567 ret = 0; 2568 fail: 2569 g_free(out_buf); 2570 return ret; 2571 } 2572 2573 static int make_completely_empty(BlockDriverState *bs) 2574 { 2575 BDRVQcow2State *s = bs->opaque; 2576 int ret, l1_clusters; 2577 int64_t offset; 2578 uint64_t *new_reftable = NULL; 2579 uint64_t rt_entry, l1_size2; 2580 struct { 2581 uint64_t l1_offset; 2582 uint64_t reftable_offset; 2583 uint32_t reftable_clusters; 2584 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2585 2586 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2587 if (ret < 0) { 2588 goto fail; 2589 } 2590 2591 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2592 if (ret < 0) { 2593 goto fail; 2594 } 2595 2596 /* Refcounts will be broken utterly */ 2597 ret = qcow2_mark_dirty(bs); 2598 if (ret < 0) { 2599 goto fail; 2600 } 2601 2602 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2603 2604 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2605 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2606 2607 /* After this call, neither the in-memory nor the on-disk refcount 2608 * information accurately describe the actual references */ 2609 2610 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, 2611 l1_clusters * s->cluster_sectors, 0); 2612 if (ret < 0) { 2613 goto fail_broken_refcounts; 2614 } 2615 memset(s->l1_table, 0, l1_size2); 2616 2617 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2618 2619 /* Overwrite enough clusters at the beginning of the sectors to place 2620 * the refcount table, a refcount block and the L1 table in; this may 2621 * overwrite parts of the existing refcount and L1 table, which is not 2622 * an issue because the dirty flag is set, complete data loss is in fact 2623 * desired and partial data loss is consequently fine as well */ 2624 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, 2625 (2 + l1_clusters) * s->cluster_size / 2626 BDRV_SECTOR_SIZE, 0); 2627 /* This call (even if it failed overall) may have overwritten on-disk 2628 * refcount structures; in that case, the in-memory refcount information 2629 * will probably differ from the on-disk information which makes the BDS 2630 * unusable */ 2631 if (ret < 0) { 2632 goto fail_broken_refcounts; 2633 } 2634 2635 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2636 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2637 2638 /* "Create" an empty reftable (one cluster) directly after the image 2639 * header and an empty L1 table three clusters after the image header; 2640 * the cluster between those two will be used as the first refblock */ 2641 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2642 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2643 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2644 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset), 2645 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2646 if (ret < 0) { 2647 goto fail_broken_refcounts; 2648 } 2649 2650 s->l1_table_offset = 3 * s->cluster_size; 2651 2652 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2653 if (!new_reftable) { 2654 ret = -ENOMEM; 2655 goto fail_broken_refcounts; 2656 } 2657 2658 s->refcount_table_offset = s->cluster_size; 2659 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2660 2661 g_free(s->refcount_table); 2662 s->refcount_table = new_reftable; 2663 new_reftable = NULL; 2664 2665 /* Now the in-memory refcount information again corresponds to the on-disk 2666 * information (reftable is empty and no refblocks (the refblock cache is 2667 * empty)); however, this means some clusters (e.g. the image header) are 2668 * referenced, but not refcounted, but the normal qcow2 code assumes that 2669 * the in-memory information is always correct */ 2670 2671 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2672 2673 /* Enter the first refblock into the reftable */ 2674 rt_entry = cpu_to_be64(2 * s->cluster_size); 2675 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size, 2676 &rt_entry, sizeof(rt_entry)); 2677 if (ret < 0) { 2678 goto fail_broken_refcounts; 2679 } 2680 s->refcount_table[0] = 2 * s->cluster_size; 2681 2682 s->free_cluster_index = 0; 2683 assert(3 + l1_clusters <= s->refcount_block_size); 2684 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2685 if (offset < 0) { 2686 ret = offset; 2687 goto fail_broken_refcounts; 2688 } else if (offset > 0) { 2689 error_report("First cluster in emptied image is in use"); 2690 abort(); 2691 } 2692 2693 /* Now finally the in-memory information corresponds to the on-disk 2694 * structures and is correct */ 2695 ret = qcow2_mark_clean(bs); 2696 if (ret < 0) { 2697 goto fail; 2698 } 2699 2700 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2701 if (ret < 0) { 2702 goto fail; 2703 } 2704 2705 return 0; 2706 2707 fail_broken_refcounts: 2708 /* The BDS is unusable at this point. If we wanted to make it usable, we 2709 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2710 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2711 * again. However, because the functions which could have caused this error 2712 * path to be taken are used by those functions as well, it's very likely 2713 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2714 bs->drv = NULL; 2715 2716 fail: 2717 g_free(new_reftable); 2718 return ret; 2719 } 2720 2721 static int qcow2_make_empty(BlockDriverState *bs) 2722 { 2723 BDRVQcow2State *s = bs->opaque; 2724 uint64_t start_sector; 2725 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2726 int l1_clusters, ret = 0; 2727 2728 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2729 2730 if (s->qcow_version >= 3 && !s->snapshots && 2731 3 + l1_clusters <= s->refcount_block_size) { 2732 /* The following function only works for qcow2 v3 images (it requires 2733 * the dirty flag) and only as long as there are no snapshots (because 2734 * it completely empties the image). Furthermore, the L1 table and three 2735 * additional clusters (image header, refcount table, one refcount 2736 * block) have to fit inside one refcount block. */ 2737 return make_completely_empty(bs); 2738 } 2739 2740 /* This fallback code simply discards every active cluster; this is slow, 2741 * but works in all cases */ 2742 for (start_sector = 0; start_sector < bs->total_sectors; 2743 start_sector += sector_step) 2744 { 2745 /* As this function is generally used after committing an external 2746 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2747 * default action for this kind of discard is to pass the discard, 2748 * which will ideally result in an actually smaller image file, as 2749 * is probably desired. */ 2750 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2751 MIN(sector_step, 2752 bs->total_sectors - start_sector), 2753 QCOW2_DISCARD_SNAPSHOT, true); 2754 if (ret < 0) { 2755 break; 2756 } 2757 } 2758 2759 return ret; 2760 } 2761 2762 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2763 { 2764 BDRVQcow2State *s = bs->opaque; 2765 int ret; 2766 2767 qemu_co_mutex_lock(&s->lock); 2768 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2769 if (ret < 0) { 2770 qemu_co_mutex_unlock(&s->lock); 2771 return ret; 2772 } 2773 2774 if (qcow2_need_accurate_refcounts(s)) { 2775 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2776 if (ret < 0) { 2777 qemu_co_mutex_unlock(&s->lock); 2778 return ret; 2779 } 2780 } 2781 qemu_co_mutex_unlock(&s->lock); 2782 2783 return 0; 2784 } 2785 2786 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2787 { 2788 BDRVQcow2State *s = bs->opaque; 2789 bdi->unallocated_blocks_are_zero = true; 2790 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2791 bdi->cluster_size = s->cluster_size; 2792 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2793 return 0; 2794 } 2795 2796 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2797 { 2798 BDRVQcow2State *s = bs->opaque; 2799 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2800 2801 *spec_info = (ImageInfoSpecific){ 2802 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2803 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 2804 }; 2805 if (s->qcow_version == 2) { 2806 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2807 .compat = g_strdup("0.10"), 2808 .refcount_bits = s->refcount_bits, 2809 }; 2810 } else if (s->qcow_version == 3) { 2811 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2812 .compat = g_strdup("1.1"), 2813 .lazy_refcounts = s->compatible_features & 2814 QCOW2_COMPAT_LAZY_REFCOUNTS, 2815 .has_lazy_refcounts = true, 2816 .corrupt = s->incompatible_features & 2817 QCOW2_INCOMPAT_CORRUPT, 2818 .has_corrupt = true, 2819 .refcount_bits = s->refcount_bits, 2820 }; 2821 } else { 2822 /* if this assertion fails, this probably means a new version was 2823 * added without having it covered here */ 2824 assert(false); 2825 } 2826 2827 return spec_info; 2828 } 2829 2830 #if 0 2831 static void dump_refcounts(BlockDriverState *bs) 2832 { 2833 BDRVQcow2State *s = bs->opaque; 2834 int64_t nb_clusters, k, k1, size; 2835 int refcount; 2836 2837 size = bdrv_getlength(bs->file->bs); 2838 nb_clusters = size_to_clusters(s, size); 2839 for(k = 0; k < nb_clusters;) { 2840 k1 = k; 2841 refcount = get_refcount(bs, k); 2842 k++; 2843 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2844 k++; 2845 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2846 k - k1); 2847 } 2848 } 2849 #endif 2850 2851 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2852 int64_t pos) 2853 { 2854 BDRVQcow2State *s = bs->opaque; 2855 int64_t total_sectors = bs->total_sectors; 2856 bool zero_beyond_eof = bs->zero_beyond_eof; 2857 int ret; 2858 2859 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2860 bs->zero_beyond_eof = false; 2861 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2862 bs->zero_beyond_eof = zero_beyond_eof; 2863 2864 /* bdrv_co_do_writev will have increased the total_sectors value to include 2865 * the VM state - the VM state is however not an actual part of the block 2866 * device, therefore, we need to restore the old value. */ 2867 bs->total_sectors = total_sectors; 2868 2869 return ret; 2870 } 2871 2872 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2873 int64_t pos, int size) 2874 { 2875 BDRVQcow2State *s = bs->opaque; 2876 bool zero_beyond_eof = bs->zero_beyond_eof; 2877 int ret; 2878 2879 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2880 bs->zero_beyond_eof = false; 2881 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2882 bs->zero_beyond_eof = zero_beyond_eof; 2883 2884 return ret; 2885 } 2886 2887 /* 2888 * Downgrades an image's version. To achieve this, any incompatible features 2889 * have to be removed. 2890 */ 2891 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2892 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2893 { 2894 BDRVQcow2State *s = bs->opaque; 2895 int current_version = s->qcow_version; 2896 int ret; 2897 2898 if (target_version == current_version) { 2899 return 0; 2900 } else if (target_version > current_version) { 2901 return -EINVAL; 2902 } else if (target_version != 2) { 2903 return -EINVAL; 2904 } 2905 2906 if (s->refcount_order != 4) { 2907 error_report("compat=0.10 requires refcount_bits=16"); 2908 return -ENOTSUP; 2909 } 2910 2911 /* clear incompatible features */ 2912 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2913 ret = qcow2_mark_clean(bs); 2914 if (ret < 0) { 2915 return ret; 2916 } 2917 } 2918 2919 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2920 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2921 * best thing to do anyway */ 2922 2923 if (s->incompatible_features) { 2924 return -ENOTSUP; 2925 } 2926 2927 /* since we can ignore compatible features, we can set them to 0 as well */ 2928 s->compatible_features = 0; 2929 /* if lazy refcounts have been used, they have already been fixed through 2930 * clearing the dirty flag */ 2931 2932 /* clearing autoclear features is trivial */ 2933 s->autoclear_features = 0; 2934 2935 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 2936 if (ret < 0) { 2937 return ret; 2938 } 2939 2940 s->qcow_version = target_version; 2941 ret = qcow2_update_header(bs); 2942 if (ret < 0) { 2943 s->qcow_version = current_version; 2944 return ret; 2945 } 2946 return 0; 2947 } 2948 2949 typedef enum Qcow2AmendOperation { 2950 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 2951 * statically initialized to so that the helper CB can discern the first 2952 * invocation from an operation change */ 2953 QCOW2_NO_OPERATION = 0, 2954 2955 QCOW2_CHANGING_REFCOUNT_ORDER, 2956 QCOW2_DOWNGRADING, 2957 } Qcow2AmendOperation; 2958 2959 typedef struct Qcow2AmendHelperCBInfo { 2960 /* The code coordinating the amend operations should only modify 2961 * these four fields; the rest will be managed by the CB */ 2962 BlockDriverAmendStatusCB *original_status_cb; 2963 void *original_cb_opaque; 2964 2965 Qcow2AmendOperation current_operation; 2966 2967 /* Total number of operations to perform (only set once) */ 2968 int total_operations; 2969 2970 /* The following fields are managed by the CB */ 2971 2972 /* Number of operations completed */ 2973 int operations_completed; 2974 2975 /* Cumulative offset of all completed operations */ 2976 int64_t offset_completed; 2977 2978 Qcow2AmendOperation last_operation; 2979 int64_t last_work_size; 2980 } Qcow2AmendHelperCBInfo; 2981 2982 static void qcow2_amend_helper_cb(BlockDriverState *bs, 2983 int64_t operation_offset, 2984 int64_t operation_work_size, void *opaque) 2985 { 2986 Qcow2AmendHelperCBInfo *info = opaque; 2987 int64_t current_work_size; 2988 int64_t projected_work_size; 2989 2990 if (info->current_operation != info->last_operation) { 2991 if (info->last_operation != QCOW2_NO_OPERATION) { 2992 info->offset_completed += info->last_work_size; 2993 info->operations_completed++; 2994 } 2995 2996 info->last_operation = info->current_operation; 2997 } 2998 2999 assert(info->total_operations > 0); 3000 assert(info->operations_completed < info->total_operations); 3001 3002 info->last_work_size = operation_work_size; 3003 3004 current_work_size = info->offset_completed + operation_work_size; 3005 3006 /* current_work_size is the total work size for (operations_completed + 1) 3007 * operations (which includes this one), so multiply it by the number of 3008 * operations not covered and divide it by the number of operations 3009 * covered to get a projection for the operations not covered */ 3010 projected_work_size = current_work_size * (info->total_operations - 3011 info->operations_completed - 1) 3012 / (info->operations_completed + 1); 3013 3014 info->original_status_cb(bs, info->offset_completed + operation_offset, 3015 current_work_size + projected_work_size, 3016 info->original_cb_opaque); 3017 } 3018 3019 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3020 BlockDriverAmendStatusCB *status_cb, 3021 void *cb_opaque) 3022 { 3023 BDRVQcow2State *s = bs->opaque; 3024 int old_version = s->qcow_version, new_version = old_version; 3025 uint64_t new_size = 0; 3026 const char *backing_file = NULL, *backing_format = NULL; 3027 bool lazy_refcounts = s->use_lazy_refcounts; 3028 const char *compat = NULL; 3029 uint64_t cluster_size = s->cluster_size; 3030 bool encrypt; 3031 int refcount_bits = s->refcount_bits; 3032 int ret; 3033 QemuOptDesc *desc = opts->list->desc; 3034 Qcow2AmendHelperCBInfo helper_cb_info; 3035 3036 while (desc && desc->name) { 3037 if (!qemu_opt_find(opts, desc->name)) { 3038 /* only change explicitly defined options */ 3039 desc++; 3040 continue; 3041 } 3042 3043 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3044 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3045 if (!compat) { 3046 /* preserve default */ 3047 } else if (!strcmp(compat, "0.10")) { 3048 new_version = 2; 3049 } else if (!strcmp(compat, "1.1")) { 3050 new_version = 3; 3051 } else { 3052 error_report("Unknown compatibility level %s", compat); 3053 return -EINVAL; 3054 } 3055 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3056 error_report("Cannot change preallocation mode"); 3057 return -ENOTSUP; 3058 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3059 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3060 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3061 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3062 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3063 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3064 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3065 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3066 !!s->cipher); 3067 3068 if (encrypt != !!s->cipher) { 3069 error_report("Changing the encryption flag is not supported"); 3070 return -ENOTSUP; 3071 } 3072 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3073 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3074 cluster_size); 3075 if (cluster_size != s->cluster_size) { 3076 error_report("Changing the cluster size is not supported"); 3077 return -ENOTSUP; 3078 } 3079 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3080 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3081 lazy_refcounts); 3082 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3083 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3084 refcount_bits); 3085 3086 if (refcount_bits <= 0 || refcount_bits > 64 || 3087 !is_power_of_2(refcount_bits)) 3088 { 3089 error_report("Refcount width must be a power of two and may " 3090 "not exceed 64 bits"); 3091 return -EINVAL; 3092 } 3093 } else { 3094 /* if this point is reached, this probably means a new option was 3095 * added without having it covered here */ 3096 abort(); 3097 } 3098 3099 desc++; 3100 } 3101 3102 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3103 .original_status_cb = status_cb, 3104 .original_cb_opaque = cb_opaque, 3105 .total_operations = (new_version < old_version) 3106 + (s->refcount_bits != refcount_bits) 3107 }; 3108 3109 /* Upgrade first (some features may require compat=1.1) */ 3110 if (new_version > old_version) { 3111 s->qcow_version = new_version; 3112 ret = qcow2_update_header(bs); 3113 if (ret < 0) { 3114 s->qcow_version = old_version; 3115 return ret; 3116 } 3117 } 3118 3119 if (s->refcount_bits != refcount_bits) { 3120 int refcount_order = ctz32(refcount_bits); 3121 Error *local_error = NULL; 3122 3123 if (new_version < 3 && refcount_bits != 16) { 3124 error_report("Different refcount widths than 16 bits require " 3125 "compatibility level 1.1 or above (use compat=1.1 or " 3126 "greater)"); 3127 return -EINVAL; 3128 } 3129 3130 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3131 ret = qcow2_change_refcount_order(bs, refcount_order, 3132 &qcow2_amend_helper_cb, 3133 &helper_cb_info, &local_error); 3134 if (ret < 0) { 3135 error_report_err(local_error); 3136 return ret; 3137 } 3138 } 3139 3140 if (backing_file || backing_format) { 3141 ret = qcow2_change_backing_file(bs, 3142 backing_file ?: s->image_backing_file, 3143 backing_format ?: s->image_backing_format); 3144 if (ret < 0) { 3145 return ret; 3146 } 3147 } 3148 3149 if (s->use_lazy_refcounts != lazy_refcounts) { 3150 if (lazy_refcounts) { 3151 if (new_version < 3) { 3152 error_report("Lazy refcounts only supported with compatibility " 3153 "level 1.1 and above (use compat=1.1 or greater)"); 3154 return -EINVAL; 3155 } 3156 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3157 ret = qcow2_update_header(bs); 3158 if (ret < 0) { 3159 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3160 return ret; 3161 } 3162 s->use_lazy_refcounts = true; 3163 } else { 3164 /* make image clean first */ 3165 ret = qcow2_mark_clean(bs); 3166 if (ret < 0) { 3167 return ret; 3168 } 3169 /* now disallow lazy refcounts */ 3170 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3171 ret = qcow2_update_header(bs); 3172 if (ret < 0) { 3173 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3174 return ret; 3175 } 3176 s->use_lazy_refcounts = false; 3177 } 3178 } 3179 3180 if (new_size) { 3181 ret = bdrv_truncate(bs, new_size); 3182 if (ret < 0) { 3183 return ret; 3184 } 3185 } 3186 3187 /* Downgrade last (so unsupported features can be removed before) */ 3188 if (new_version < old_version) { 3189 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3190 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3191 &helper_cb_info); 3192 if (ret < 0) { 3193 return ret; 3194 } 3195 } 3196 3197 return 0; 3198 } 3199 3200 /* 3201 * If offset or size are negative, respectively, they will not be included in 3202 * the BLOCK_IMAGE_CORRUPTED event emitted. 3203 * fatal will be ignored for read-only BDS; corruptions found there will always 3204 * be considered non-fatal. 3205 */ 3206 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3207 int64_t size, const char *message_format, ...) 3208 { 3209 BDRVQcow2State *s = bs->opaque; 3210 const char *node_name; 3211 char *message; 3212 va_list ap; 3213 3214 fatal = fatal && !bs->read_only; 3215 3216 if (s->signaled_corruption && 3217 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3218 { 3219 return; 3220 } 3221 3222 va_start(ap, message_format); 3223 message = g_strdup_vprintf(message_format, ap); 3224 va_end(ap); 3225 3226 if (fatal) { 3227 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3228 "corruption events will be suppressed\n", message); 3229 } else { 3230 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3231 "corruption events will be suppressed\n", message); 3232 } 3233 3234 node_name = bdrv_get_node_name(bs); 3235 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3236 *node_name != '\0', node_name, 3237 message, offset >= 0, offset, 3238 size >= 0, size, 3239 fatal, &error_abort); 3240 g_free(message); 3241 3242 if (fatal) { 3243 qcow2_mark_corrupt(bs); 3244 bs->drv = NULL; /* make BDS unusable */ 3245 } 3246 3247 s->signaled_corruption = true; 3248 } 3249 3250 static QemuOptsList qcow2_create_opts = { 3251 .name = "qcow2-create-opts", 3252 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3253 .desc = { 3254 { 3255 .name = BLOCK_OPT_SIZE, 3256 .type = QEMU_OPT_SIZE, 3257 .help = "Virtual disk size" 3258 }, 3259 { 3260 .name = BLOCK_OPT_COMPAT_LEVEL, 3261 .type = QEMU_OPT_STRING, 3262 .help = "Compatibility level (0.10 or 1.1)" 3263 }, 3264 { 3265 .name = BLOCK_OPT_BACKING_FILE, 3266 .type = QEMU_OPT_STRING, 3267 .help = "File name of a base image" 3268 }, 3269 { 3270 .name = BLOCK_OPT_BACKING_FMT, 3271 .type = QEMU_OPT_STRING, 3272 .help = "Image format of the base image" 3273 }, 3274 { 3275 .name = BLOCK_OPT_ENCRYPT, 3276 .type = QEMU_OPT_BOOL, 3277 .help = "Encrypt the image", 3278 .def_value_str = "off" 3279 }, 3280 { 3281 .name = BLOCK_OPT_CLUSTER_SIZE, 3282 .type = QEMU_OPT_SIZE, 3283 .help = "qcow2 cluster size", 3284 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3285 }, 3286 { 3287 .name = BLOCK_OPT_PREALLOC, 3288 .type = QEMU_OPT_STRING, 3289 .help = "Preallocation mode (allowed values: off, metadata, " 3290 "falloc, full)" 3291 }, 3292 { 3293 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3294 .type = QEMU_OPT_BOOL, 3295 .help = "Postpone refcount updates", 3296 .def_value_str = "off" 3297 }, 3298 { 3299 .name = BLOCK_OPT_REFCOUNT_BITS, 3300 .type = QEMU_OPT_NUMBER, 3301 .help = "Width of a reference count entry in bits", 3302 .def_value_str = "16" 3303 }, 3304 { /* end of list */ } 3305 } 3306 }; 3307 3308 BlockDriver bdrv_qcow2 = { 3309 .format_name = "qcow2", 3310 .instance_size = sizeof(BDRVQcow2State), 3311 .bdrv_probe = qcow2_probe, 3312 .bdrv_open = qcow2_open, 3313 .bdrv_close = qcow2_close, 3314 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3315 .bdrv_reopen_commit = qcow2_reopen_commit, 3316 .bdrv_reopen_abort = qcow2_reopen_abort, 3317 .bdrv_join_options = qcow2_join_options, 3318 .bdrv_create = qcow2_create, 3319 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3320 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3321 .bdrv_set_key = qcow2_set_key, 3322 3323 .bdrv_co_readv = qcow2_co_readv, 3324 .bdrv_co_writev = qcow2_co_writev, 3325 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3326 3327 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3328 .bdrv_co_discard = qcow2_co_discard, 3329 .bdrv_truncate = qcow2_truncate, 3330 .bdrv_write_compressed = qcow2_write_compressed, 3331 .bdrv_make_empty = qcow2_make_empty, 3332 3333 .bdrv_snapshot_create = qcow2_snapshot_create, 3334 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3335 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3336 .bdrv_snapshot_list = qcow2_snapshot_list, 3337 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3338 .bdrv_get_info = qcow2_get_info, 3339 .bdrv_get_specific_info = qcow2_get_specific_info, 3340 3341 .bdrv_save_vmstate = qcow2_save_vmstate, 3342 .bdrv_load_vmstate = qcow2_load_vmstate, 3343 3344 .supports_backing = true, 3345 .bdrv_change_backing_file = qcow2_change_backing_file, 3346 3347 .bdrv_refresh_limits = qcow2_refresh_limits, 3348 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3349 .bdrv_inactivate = qcow2_inactivate, 3350 3351 .create_opts = &qcow2_create_opts, 3352 .bdrv_check = qcow2_check, 3353 .bdrv_amend_options = qcow2_amend_options, 3354 3355 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3356 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3357 }; 3358 3359 static void bdrv_qcow2_init(void) 3360 { 3361 bdrv_register(&bdrv_qcow2); 3362 } 3363 3364 block_init(bdrv_qcow2_init); 3365