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 "block/block_int.h" 26 #include "sysemu/block-backend.h" 27 #include "qemu/module.h" 28 #include <zlib.h> 29 #include "block/qcow2.h" 30 #include "qemu/error-report.h" 31 #include "qapi/qmp/qerror.h" 32 #include "qapi/qmp/qbool.h" 33 #include "qapi/util.h" 34 #include "qapi/qmp/types.h" 35 #include "qapi-event.h" 36 #include "trace.h" 37 #include "qemu/option_int.h" 38 #include "qemu/cutils.h" 39 #include "qemu/bswap.h" 40 41 /* 42 Differences with QCOW: 43 44 - Support for multiple incremental snapshots. 45 - Memory management by reference counts. 46 - Clusters which have a reference count of one have the bit 47 QCOW_OFLAG_COPIED to optimize write performance. 48 - Size of compressed clusters is stored in sectors to reduce bit usage 49 in the cluster offsets. 50 - Support for storing additional data (such as the VM state) in the 51 snapshots. 52 - If a backing store is used, the cluster size is not constrained 53 (could be backported to QCOW). 54 - L2 tables have always a size of one cluster. 55 */ 56 57 58 typedef struct { 59 uint32_t magic; 60 uint32_t len; 61 } QEMU_PACKED QCowExtension; 62 63 #define QCOW2_EXT_MAGIC_END 0 64 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 65 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 66 67 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 68 { 69 const QCowHeader *cow_header = (const void *)buf; 70 71 if (buf_size >= sizeof(QCowHeader) && 72 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 73 be32_to_cpu(cow_header->version) >= 2) 74 return 100; 75 else 76 return 0; 77 } 78 79 80 /* 81 * read qcow2 extension and fill bs 82 * start reading from start_offset 83 * finish reading upon magic of value 0 or when end_offset reached 84 * unknown magic is skipped (future extension this version knows nothing about) 85 * return 0 upon success, non-0 otherwise 86 */ 87 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 88 uint64_t end_offset, void **p_feature_table, 89 Error **errp) 90 { 91 BDRVQcow2State *s = bs->opaque; 92 QCowExtension ext; 93 uint64_t offset; 94 int ret; 95 96 #ifdef DEBUG_EXT 97 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 98 #endif 99 offset = start_offset; 100 while (offset < end_offset) { 101 102 #ifdef DEBUG_EXT 103 /* Sanity check */ 104 if (offset > s->cluster_size) 105 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 106 107 printf("attempting to read extended header in offset %lu\n", offset); 108 #endif 109 110 ret = bdrv_pread(bs->file->bs, offset, &ext, sizeof(ext)); 111 if (ret < 0) { 112 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 113 "pread fail from offset %" PRIu64, offset); 114 return 1; 115 } 116 be32_to_cpus(&ext.magic); 117 be32_to_cpus(&ext.len); 118 offset += sizeof(ext); 119 #ifdef DEBUG_EXT 120 printf("ext.magic = 0x%x\n", ext.magic); 121 #endif 122 if (offset > end_offset || ext.len > end_offset - offset) { 123 error_setg(errp, "Header extension too large"); 124 return -EINVAL; 125 } 126 127 switch (ext.magic) { 128 case QCOW2_EXT_MAGIC_END: 129 return 0; 130 131 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 132 if (ext.len >= sizeof(bs->backing_format)) { 133 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 134 " too large (>=%zu)", ext.len, 135 sizeof(bs->backing_format)); 136 return 2; 137 } 138 ret = bdrv_pread(bs->file->bs, offset, bs->backing_format, ext.len); 139 if (ret < 0) { 140 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 141 "Could not read format name"); 142 return 3; 143 } 144 bs->backing_format[ext.len] = '\0'; 145 s->image_backing_format = g_strdup(bs->backing_format); 146 #ifdef DEBUG_EXT 147 printf("Qcow2: Got format extension %s\n", bs->backing_format); 148 #endif 149 break; 150 151 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 152 if (p_feature_table != NULL) { 153 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 154 ret = bdrv_pread(bs->file->bs, offset , feature_table, ext.len); 155 if (ret < 0) { 156 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 157 "Could not read table"); 158 return ret; 159 } 160 161 *p_feature_table = feature_table; 162 } 163 break; 164 165 default: 166 /* unknown magic - save it in case we need to rewrite the header */ 167 { 168 Qcow2UnknownHeaderExtension *uext; 169 170 uext = g_malloc0(sizeof(*uext) + ext.len); 171 uext->magic = ext.magic; 172 uext->len = ext.len; 173 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 174 175 ret = bdrv_pread(bs->file->bs, offset , uext->data, uext->len); 176 if (ret < 0) { 177 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 178 "Could not read data"); 179 return ret; 180 } 181 } 182 break; 183 } 184 185 offset += ((ext.len + 7) & ~7); 186 } 187 188 return 0; 189 } 190 191 static void cleanup_unknown_header_ext(BlockDriverState *bs) 192 { 193 BDRVQcow2State *s = bs->opaque; 194 Qcow2UnknownHeaderExtension *uext, *next; 195 196 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 197 QLIST_REMOVE(uext, next); 198 g_free(uext); 199 } 200 } 201 202 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 203 uint64_t mask) 204 { 205 char *features = g_strdup(""); 206 char *old; 207 208 while (table && table->name[0] != '\0') { 209 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 210 if (mask & (1ULL << table->bit)) { 211 old = features; 212 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 213 table->name); 214 g_free(old); 215 mask &= ~(1ULL << table->bit); 216 } 217 } 218 table++; 219 } 220 221 if (mask) { 222 old = features; 223 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 224 old, *old ? ", " : "", mask); 225 g_free(old); 226 } 227 228 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 229 g_free(features); 230 } 231 232 /* 233 * Sets the dirty bit and flushes afterwards if necessary. 234 * 235 * The incompatible_features bit is only set if the image file header was 236 * updated successfully. Therefore it is not required to check the return 237 * value of this function. 238 */ 239 int qcow2_mark_dirty(BlockDriverState *bs) 240 { 241 BDRVQcow2State *s = bs->opaque; 242 uint64_t val; 243 int ret; 244 245 assert(s->qcow_version >= 3); 246 247 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 248 return 0; /* already dirty */ 249 } 250 251 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 252 ret = bdrv_pwrite(bs->file->bs, offsetof(QCowHeader, incompatible_features), 253 &val, sizeof(val)); 254 if (ret < 0) { 255 return ret; 256 } 257 ret = bdrv_flush(bs->file->bs); 258 if (ret < 0) { 259 return ret; 260 } 261 262 /* Only treat image as dirty if the header was updated successfully */ 263 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 264 return 0; 265 } 266 267 /* 268 * Clears the dirty bit and flushes before if necessary. Only call this 269 * function when there are no pending requests, it does not guard against 270 * concurrent requests dirtying the image. 271 */ 272 static int qcow2_mark_clean(BlockDriverState *bs) 273 { 274 BDRVQcow2State *s = bs->opaque; 275 276 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 277 int ret; 278 279 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 280 281 ret = bdrv_flush(bs); 282 if (ret < 0) { 283 return ret; 284 } 285 286 return qcow2_update_header(bs); 287 } 288 return 0; 289 } 290 291 /* 292 * Marks the image as corrupt. 293 */ 294 int qcow2_mark_corrupt(BlockDriverState *bs) 295 { 296 BDRVQcow2State *s = bs->opaque; 297 298 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 299 return qcow2_update_header(bs); 300 } 301 302 /* 303 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 304 * before if necessary. 305 */ 306 int qcow2_mark_consistent(BlockDriverState *bs) 307 { 308 BDRVQcow2State *s = bs->opaque; 309 310 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 311 int ret = bdrv_flush(bs); 312 if (ret < 0) { 313 return ret; 314 } 315 316 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 317 return qcow2_update_header(bs); 318 } 319 return 0; 320 } 321 322 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 323 BdrvCheckMode fix) 324 { 325 int ret = qcow2_check_refcounts(bs, result, fix); 326 if (ret < 0) { 327 return ret; 328 } 329 330 if (fix && result->check_errors == 0 && result->corruptions == 0) { 331 ret = qcow2_mark_clean(bs); 332 if (ret < 0) { 333 return ret; 334 } 335 return qcow2_mark_consistent(bs); 336 } 337 return ret; 338 } 339 340 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 341 uint64_t entries, size_t entry_len) 342 { 343 BDRVQcow2State *s = bs->opaque; 344 uint64_t size; 345 346 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 347 * because values will be passed to qemu functions taking int64_t. */ 348 if (entries > INT64_MAX / entry_len) { 349 return -EINVAL; 350 } 351 352 size = entries * entry_len; 353 354 if (INT64_MAX - size < offset) { 355 return -EINVAL; 356 } 357 358 /* Tables must be cluster aligned */ 359 if (offset & (s->cluster_size - 1)) { 360 return -EINVAL; 361 } 362 363 return 0; 364 } 365 366 static QemuOptsList qcow2_runtime_opts = { 367 .name = "qcow2", 368 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 369 .desc = { 370 { 371 .name = QCOW2_OPT_LAZY_REFCOUNTS, 372 .type = QEMU_OPT_BOOL, 373 .help = "Postpone refcount updates", 374 }, 375 { 376 .name = QCOW2_OPT_DISCARD_REQUEST, 377 .type = QEMU_OPT_BOOL, 378 .help = "Pass guest discard requests to the layer below", 379 }, 380 { 381 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 382 .type = QEMU_OPT_BOOL, 383 .help = "Generate discard requests when snapshot related space " 384 "is freed", 385 }, 386 { 387 .name = QCOW2_OPT_DISCARD_OTHER, 388 .type = QEMU_OPT_BOOL, 389 .help = "Generate discard requests when other clusters are freed", 390 }, 391 { 392 .name = QCOW2_OPT_OVERLAP, 393 .type = QEMU_OPT_STRING, 394 .help = "Selects which overlap checks to perform from a range of " 395 "templates (none, constant, cached, all)", 396 }, 397 { 398 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 399 .type = QEMU_OPT_STRING, 400 .help = "Selects which overlap checks to perform from a range of " 401 "templates (none, constant, cached, all)", 402 }, 403 { 404 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 405 .type = QEMU_OPT_BOOL, 406 .help = "Check for unintended writes into the main qcow2 header", 407 }, 408 { 409 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 410 .type = QEMU_OPT_BOOL, 411 .help = "Check for unintended writes into the active L1 table", 412 }, 413 { 414 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 415 .type = QEMU_OPT_BOOL, 416 .help = "Check for unintended writes into an active L2 table", 417 }, 418 { 419 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 420 .type = QEMU_OPT_BOOL, 421 .help = "Check for unintended writes into the refcount table", 422 }, 423 { 424 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 425 .type = QEMU_OPT_BOOL, 426 .help = "Check for unintended writes into a refcount block", 427 }, 428 { 429 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 430 .type = QEMU_OPT_BOOL, 431 .help = "Check for unintended writes into the snapshot table", 432 }, 433 { 434 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 435 .type = QEMU_OPT_BOOL, 436 .help = "Check for unintended writes into an inactive L1 table", 437 }, 438 { 439 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 440 .type = QEMU_OPT_BOOL, 441 .help = "Check for unintended writes into an inactive L2 table", 442 }, 443 { 444 .name = QCOW2_OPT_CACHE_SIZE, 445 .type = QEMU_OPT_SIZE, 446 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 447 "cache size", 448 }, 449 { 450 .name = QCOW2_OPT_L2_CACHE_SIZE, 451 .type = QEMU_OPT_SIZE, 452 .help = "Maximum L2 table cache size", 453 }, 454 { 455 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 456 .type = QEMU_OPT_SIZE, 457 .help = "Maximum refcount block cache size", 458 }, 459 { 460 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 461 .type = QEMU_OPT_NUMBER, 462 .help = "Clean unused cache entries after this time (in seconds)", 463 }, 464 { /* end of list */ } 465 }, 466 }; 467 468 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 469 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 470 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 471 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 472 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 473 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 474 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 475 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 476 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 477 }; 478 479 static void cache_clean_timer_cb(void *opaque) 480 { 481 BlockDriverState *bs = opaque; 482 BDRVQcow2State *s = bs->opaque; 483 qcow2_cache_clean_unused(bs, s->l2_table_cache); 484 qcow2_cache_clean_unused(bs, s->refcount_block_cache); 485 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 486 (int64_t) s->cache_clean_interval * 1000); 487 } 488 489 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 490 { 491 BDRVQcow2State *s = bs->opaque; 492 if (s->cache_clean_interval > 0) { 493 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 494 SCALE_MS, cache_clean_timer_cb, 495 bs); 496 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 497 (int64_t) s->cache_clean_interval * 1000); 498 } 499 } 500 501 static void cache_clean_timer_del(BlockDriverState *bs) 502 { 503 BDRVQcow2State *s = bs->opaque; 504 if (s->cache_clean_timer) { 505 timer_del(s->cache_clean_timer); 506 timer_free(s->cache_clean_timer); 507 s->cache_clean_timer = NULL; 508 } 509 } 510 511 static void qcow2_detach_aio_context(BlockDriverState *bs) 512 { 513 cache_clean_timer_del(bs); 514 } 515 516 static void qcow2_attach_aio_context(BlockDriverState *bs, 517 AioContext *new_context) 518 { 519 cache_clean_timer_init(bs, new_context); 520 } 521 522 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 523 uint64_t *l2_cache_size, 524 uint64_t *refcount_cache_size, Error **errp) 525 { 526 BDRVQcow2State *s = bs->opaque; 527 uint64_t combined_cache_size; 528 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 529 530 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 531 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 532 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 533 534 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 535 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 536 *refcount_cache_size = qemu_opt_get_size(opts, 537 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 538 539 if (combined_cache_size_set) { 540 if (l2_cache_size_set && refcount_cache_size_set) { 541 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 542 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 543 "the same time"); 544 return; 545 } else if (*l2_cache_size > combined_cache_size) { 546 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 547 QCOW2_OPT_CACHE_SIZE); 548 return; 549 } else if (*refcount_cache_size > combined_cache_size) { 550 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 551 QCOW2_OPT_CACHE_SIZE); 552 return; 553 } 554 555 if (l2_cache_size_set) { 556 *refcount_cache_size = combined_cache_size - *l2_cache_size; 557 } else if (refcount_cache_size_set) { 558 *l2_cache_size = combined_cache_size - *refcount_cache_size; 559 } else { 560 *refcount_cache_size = combined_cache_size 561 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 562 *l2_cache_size = combined_cache_size - *refcount_cache_size; 563 } 564 } else { 565 if (!l2_cache_size_set && !refcount_cache_size_set) { 566 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 567 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 568 * s->cluster_size); 569 *refcount_cache_size = *l2_cache_size 570 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 571 } else if (!l2_cache_size_set) { 572 *l2_cache_size = *refcount_cache_size 573 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 574 } else if (!refcount_cache_size_set) { 575 *refcount_cache_size = *l2_cache_size 576 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 577 } 578 } 579 } 580 581 typedef struct Qcow2ReopenState { 582 Qcow2Cache *l2_table_cache; 583 Qcow2Cache *refcount_block_cache; 584 bool use_lazy_refcounts; 585 int overlap_check; 586 bool discard_passthrough[QCOW2_DISCARD_MAX]; 587 uint64_t cache_clean_interval; 588 } Qcow2ReopenState; 589 590 static int qcow2_update_options_prepare(BlockDriverState *bs, 591 Qcow2ReopenState *r, 592 QDict *options, int flags, 593 Error **errp) 594 { 595 BDRVQcow2State *s = bs->opaque; 596 QemuOpts *opts = NULL; 597 const char *opt_overlap_check, *opt_overlap_check_template; 598 int overlap_check_template = 0; 599 uint64_t l2_cache_size, refcount_cache_size; 600 int i; 601 Error *local_err = NULL; 602 int ret; 603 604 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 605 qemu_opts_absorb_qdict(opts, options, &local_err); 606 if (local_err) { 607 error_propagate(errp, local_err); 608 ret = -EINVAL; 609 goto fail; 610 } 611 612 /* get L2 table/refcount block cache size from command line options */ 613 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 614 &local_err); 615 if (local_err) { 616 error_propagate(errp, local_err); 617 ret = -EINVAL; 618 goto fail; 619 } 620 621 l2_cache_size /= s->cluster_size; 622 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 623 l2_cache_size = MIN_L2_CACHE_SIZE; 624 } 625 if (l2_cache_size > INT_MAX) { 626 error_setg(errp, "L2 cache size too big"); 627 ret = -EINVAL; 628 goto fail; 629 } 630 631 refcount_cache_size /= s->cluster_size; 632 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 633 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 634 } 635 if (refcount_cache_size > INT_MAX) { 636 error_setg(errp, "Refcount cache size too big"); 637 ret = -EINVAL; 638 goto fail; 639 } 640 641 /* alloc new L2 table/refcount block cache, flush old one */ 642 if (s->l2_table_cache) { 643 ret = qcow2_cache_flush(bs, s->l2_table_cache); 644 if (ret) { 645 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 646 goto fail; 647 } 648 } 649 650 if (s->refcount_block_cache) { 651 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 652 if (ret) { 653 error_setg_errno(errp, -ret, 654 "Failed to flush the refcount block cache"); 655 goto fail; 656 } 657 } 658 659 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 660 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 661 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 662 error_setg(errp, "Could not allocate metadata caches"); 663 ret = -ENOMEM; 664 goto fail; 665 } 666 667 /* New interval for cache cleanup timer */ 668 r->cache_clean_interval = 669 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 670 s->cache_clean_interval); 671 if (r->cache_clean_interval > UINT_MAX) { 672 error_setg(errp, "Cache clean interval too big"); 673 ret = -EINVAL; 674 goto fail; 675 } 676 677 /* lazy-refcounts; flush if going from enabled to disabled */ 678 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 679 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 680 if (r->use_lazy_refcounts && s->qcow_version < 3) { 681 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 682 "qemu 1.1 compatibility level"); 683 ret = -EINVAL; 684 goto fail; 685 } 686 687 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 688 ret = qcow2_mark_clean(bs); 689 if (ret < 0) { 690 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 691 goto fail; 692 } 693 } 694 695 /* Overlap check options */ 696 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 697 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 698 if (opt_overlap_check_template && opt_overlap_check && 699 strcmp(opt_overlap_check_template, opt_overlap_check)) 700 { 701 error_setg(errp, "Conflicting values for qcow2 options '" 702 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 703 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 704 ret = -EINVAL; 705 goto fail; 706 } 707 if (!opt_overlap_check) { 708 opt_overlap_check = opt_overlap_check_template ?: "cached"; 709 } 710 711 if (!strcmp(opt_overlap_check, "none")) { 712 overlap_check_template = 0; 713 } else if (!strcmp(opt_overlap_check, "constant")) { 714 overlap_check_template = QCOW2_OL_CONSTANT; 715 } else if (!strcmp(opt_overlap_check, "cached")) { 716 overlap_check_template = QCOW2_OL_CACHED; 717 } else if (!strcmp(opt_overlap_check, "all")) { 718 overlap_check_template = QCOW2_OL_ALL; 719 } else { 720 error_setg(errp, "Unsupported value '%s' for qcow2 option " 721 "'overlap-check'. Allowed are any of the following: " 722 "none, constant, cached, all", opt_overlap_check); 723 ret = -EINVAL; 724 goto fail; 725 } 726 727 r->overlap_check = 0; 728 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 729 /* overlap-check defines a template bitmask, but every flag may be 730 * overwritten through the associated boolean option */ 731 r->overlap_check |= 732 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 733 overlap_check_template & (1 << i)) << i; 734 } 735 736 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 737 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 738 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 739 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 740 flags & BDRV_O_UNMAP); 741 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 742 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 743 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 744 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 745 746 ret = 0; 747 fail: 748 qemu_opts_del(opts); 749 opts = NULL; 750 return ret; 751 } 752 753 static void qcow2_update_options_commit(BlockDriverState *bs, 754 Qcow2ReopenState *r) 755 { 756 BDRVQcow2State *s = bs->opaque; 757 int i; 758 759 if (s->l2_table_cache) { 760 qcow2_cache_destroy(bs, s->l2_table_cache); 761 } 762 if (s->refcount_block_cache) { 763 qcow2_cache_destroy(bs, s->refcount_block_cache); 764 } 765 s->l2_table_cache = r->l2_table_cache; 766 s->refcount_block_cache = r->refcount_block_cache; 767 768 s->overlap_check = r->overlap_check; 769 s->use_lazy_refcounts = r->use_lazy_refcounts; 770 771 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 772 s->discard_passthrough[i] = r->discard_passthrough[i]; 773 } 774 775 if (s->cache_clean_interval != r->cache_clean_interval) { 776 cache_clean_timer_del(bs); 777 s->cache_clean_interval = r->cache_clean_interval; 778 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 779 } 780 } 781 782 static void qcow2_update_options_abort(BlockDriverState *bs, 783 Qcow2ReopenState *r) 784 { 785 if (r->l2_table_cache) { 786 qcow2_cache_destroy(bs, r->l2_table_cache); 787 } 788 if (r->refcount_block_cache) { 789 qcow2_cache_destroy(bs, r->refcount_block_cache); 790 } 791 } 792 793 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 794 int flags, Error **errp) 795 { 796 Qcow2ReopenState r = {}; 797 int ret; 798 799 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 800 if (ret >= 0) { 801 qcow2_update_options_commit(bs, &r); 802 } else { 803 qcow2_update_options_abort(bs, &r); 804 } 805 806 return ret; 807 } 808 809 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 810 Error **errp) 811 { 812 BDRVQcow2State *s = bs->opaque; 813 unsigned int len, i; 814 int ret = 0; 815 QCowHeader header; 816 Error *local_err = NULL; 817 uint64_t ext_end; 818 uint64_t l1_vm_state_index; 819 820 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 821 if (ret < 0) { 822 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 823 goto fail; 824 } 825 be32_to_cpus(&header.magic); 826 be32_to_cpus(&header.version); 827 be64_to_cpus(&header.backing_file_offset); 828 be32_to_cpus(&header.backing_file_size); 829 be64_to_cpus(&header.size); 830 be32_to_cpus(&header.cluster_bits); 831 be32_to_cpus(&header.crypt_method); 832 be64_to_cpus(&header.l1_table_offset); 833 be32_to_cpus(&header.l1_size); 834 be64_to_cpus(&header.refcount_table_offset); 835 be32_to_cpus(&header.refcount_table_clusters); 836 be64_to_cpus(&header.snapshots_offset); 837 be32_to_cpus(&header.nb_snapshots); 838 839 if (header.magic != QCOW_MAGIC) { 840 error_setg(errp, "Image is not in qcow2 format"); 841 ret = -EINVAL; 842 goto fail; 843 } 844 if (header.version < 2 || header.version > 3) { 845 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 846 ret = -ENOTSUP; 847 goto fail; 848 } 849 850 s->qcow_version = header.version; 851 852 /* Initialise cluster size */ 853 if (header.cluster_bits < MIN_CLUSTER_BITS || 854 header.cluster_bits > MAX_CLUSTER_BITS) { 855 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 856 header.cluster_bits); 857 ret = -EINVAL; 858 goto fail; 859 } 860 861 s->cluster_bits = header.cluster_bits; 862 s->cluster_size = 1 << s->cluster_bits; 863 s->cluster_sectors = 1 << (s->cluster_bits - 9); 864 865 /* Initialise version 3 header fields */ 866 if (header.version == 2) { 867 header.incompatible_features = 0; 868 header.compatible_features = 0; 869 header.autoclear_features = 0; 870 header.refcount_order = 4; 871 header.header_length = 72; 872 } else { 873 be64_to_cpus(&header.incompatible_features); 874 be64_to_cpus(&header.compatible_features); 875 be64_to_cpus(&header.autoclear_features); 876 be32_to_cpus(&header.refcount_order); 877 be32_to_cpus(&header.header_length); 878 879 if (header.header_length < 104) { 880 error_setg(errp, "qcow2 header too short"); 881 ret = -EINVAL; 882 goto fail; 883 } 884 } 885 886 if (header.header_length > s->cluster_size) { 887 error_setg(errp, "qcow2 header exceeds cluster size"); 888 ret = -EINVAL; 889 goto fail; 890 } 891 892 if (header.header_length > sizeof(header)) { 893 s->unknown_header_fields_size = header.header_length - sizeof(header); 894 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 895 ret = bdrv_pread(bs->file->bs, sizeof(header), s->unknown_header_fields, 896 s->unknown_header_fields_size); 897 if (ret < 0) { 898 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 899 "fields"); 900 goto fail; 901 } 902 } 903 904 if (header.backing_file_offset > s->cluster_size) { 905 error_setg(errp, "Invalid backing file offset"); 906 ret = -EINVAL; 907 goto fail; 908 } 909 910 if (header.backing_file_offset) { 911 ext_end = header.backing_file_offset; 912 } else { 913 ext_end = 1 << header.cluster_bits; 914 } 915 916 /* Handle feature bits */ 917 s->incompatible_features = header.incompatible_features; 918 s->compatible_features = header.compatible_features; 919 s->autoclear_features = header.autoclear_features; 920 921 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 922 void *feature_table = NULL; 923 qcow2_read_extensions(bs, header.header_length, ext_end, 924 &feature_table, NULL); 925 report_unsupported_feature(errp, feature_table, 926 s->incompatible_features & 927 ~QCOW2_INCOMPAT_MASK); 928 ret = -ENOTSUP; 929 g_free(feature_table); 930 goto fail; 931 } 932 933 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 934 /* Corrupt images may not be written to unless they are being repaired 935 */ 936 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 937 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 938 "read/write"); 939 ret = -EACCES; 940 goto fail; 941 } 942 } 943 944 /* Check support for various header values */ 945 if (header.refcount_order > 6) { 946 error_setg(errp, "Reference count entry width too large; may not " 947 "exceed 64 bits"); 948 ret = -EINVAL; 949 goto fail; 950 } 951 s->refcount_order = header.refcount_order; 952 s->refcount_bits = 1 << s->refcount_order; 953 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 954 s->refcount_max += s->refcount_max - 1; 955 956 if (header.crypt_method > QCOW_CRYPT_AES) { 957 error_setg(errp, "Unsupported encryption method: %" PRIu32, 958 header.crypt_method); 959 ret = -EINVAL; 960 goto fail; 961 } 962 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 963 error_setg(errp, "AES cipher not available"); 964 ret = -EINVAL; 965 goto fail; 966 } 967 s->crypt_method_header = header.crypt_method; 968 if (s->crypt_method_header) { 969 if (bdrv_uses_whitelist() && 970 s->crypt_method_header == QCOW_CRYPT_AES) { 971 error_report("qcow2 built-in AES encryption is deprecated"); 972 error_printf("Support for it will be removed in a future release.\n" 973 "You can use 'qemu-img convert' to switch to an\n" 974 "unencrypted qcow2 image, or a LUKS raw image.\n"); 975 } 976 977 bs->encrypted = 1; 978 } 979 980 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 981 s->l2_size = 1 << s->l2_bits; 982 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 983 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 984 s->refcount_block_size = 1 << s->refcount_block_bits; 985 bs->total_sectors = header.size / 512; 986 s->csize_shift = (62 - (s->cluster_bits - 8)); 987 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 988 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 989 990 s->refcount_table_offset = header.refcount_table_offset; 991 s->refcount_table_size = 992 header.refcount_table_clusters << (s->cluster_bits - 3); 993 994 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 995 error_setg(errp, "Reference count table too large"); 996 ret = -EINVAL; 997 goto fail; 998 } 999 1000 ret = validate_table_offset(bs, s->refcount_table_offset, 1001 s->refcount_table_size, sizeof(uint64_t)); 1002 if (ret < 0) { 1003 error_setg(errp, "Invalid reference count table offset"); 1004 goto fail; 1005 } 1006 1007 /* Snapshot table offset/length */ 1008 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1009 error_setg(errp, "Too many snapshots"); 1010 ret = -EINVAL; 1011 goto fail; 1012 } 1013 1014 ret = validate_table_offset(bs, header.snapshots_offset, 1015 header.nb_snapshots, 1016 sizeof(QCowSnapshotHeader)); 1017 if (ret < 0) { 1018 error_setg(errp, "Invalid snapshot table offset"); 1019 goto fail; 1020 } 1021 1022 /* read the level 1 table */ 1023 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1024 error_setg(errp, "Active L1 table too large"); 1025 ret = -EFBIG; 1026 goto fail; 1027 } 1028 s->l1_size = header.l1_size; 1029 1030 l1_vm_state_index = size_to_l1(s, header.size); 1031 if (l1_vm_state_index > INT_MAX) { 1032 error_setg(errp, "Image is too big"); 1033 ret = -EFBIG; 1034 goto fail; 1035 } 1036 s->l1_vm_state_index = l1_vm_state_index; 1037 1038 /* the L1 table must contain at least enough entries to put 1039 header.size bytes */ 1040 if (s->l1_size < s->l1_vm_state_index) { 1041 error_setg(errp, "L1 table is too small"); 1042 ret = -EINVAL; 1043 goto fail; 1044 } 1045 1046 ret = validate_table_offset(bs, header.l1_table_offset, 1047 header.l1_size, sizeof(uint64_t)); 1048 if (ret < 0) { 1049 error_setg(errp, "Invalid L1 table offset"); 1050 goto fail; 1051 } 1052 s->l1_table_offset = header.l1_table_offset; 1053 1054 1055 if (s->l1_size > 0) { 1056 s->l1_table = qemu_try_blockalign(bs->file->bs, 1057 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1058 if (s->l1_table == NULL) { 1059 error_setg(errp, "Could not allocate L1 table"); 1060 ret = -ENOMEM; 1061 goto fail; 1062 } 1063 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 1064 s->l1_size * sizeof(uint64_t)); 1065 if (ret < 0) { 1066 error_setg_errno(errp, -ret, "Could not read L1 table"); 1067 goto fail; 1068 } 1069 for(i = 0;i < s->l1_size; i++) { 1070 be64_to_cpus(&s->l1_table[i]); 1071 } 1072 } 1073 1074 /* Parse driver-specific options */ 1075 ret = qcow2_update_options(bs, options, flags, errp); 1076 if (ret < 0) { 1077 goto fail; 1078 } 1079 1080 s->cluster_cache = g_malloc(s->cluster_size); 1081 /* one more sector for decompressed data alignment */ 1082 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1083 * s->cluster_size + 512); 1084 if (s->cluster_data == NULL) { 1085 error_setg(errp, "Could not allocate temporary cluster buffer"); 1086 ret = -ENOMEM; 1087 goto fail; 1088 } 1089 1090 s->cluster_cache_offset = -1; 1091 s->flags = flags; 1092 1093 ret = qcow2_refcount_init(bs); 1094 if (ret != 0) { 1095 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1096 goto fail; 1097 } 1098 1099 QLIST_INIT(&s->cluster_allocs); 1100 QTAILQ_INIT(&s->discards); 1101 1102 /* read qcow2 extensions */ 1103 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1104 &local_err)) { 1105 error_propagate(errp, local_err); 1106 ret = -EINVAL; 1107 goto fail; 1108 } 1109 1110 /* read the backing file name */ 1111 if (header.backing_file_offset != 0) { 1112 len = header.backing_file_size; 1113 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1114 len >= sizeof(bs->backing_file)) { 1115 error_setg(errp, "Backing file name too long"); 1116 ret = -EINVAL; 1117 goto fail; 1118 } 1119 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 1120 bs->backing_file, len); 1121 if (ret < 0) { 1122 error_setg_errno(errp, -ret, "Could not read backing file name"); 1123 goto fail; 1124 } 1125 bs->backing_file[len] = '\0'; 1126 s->image_backing_file = g_strdup(bs->backing_file); 1127 } 1128 1129 /* Internal snapshots */ 1130 s->snapshots_offset = header.snapshots_offset; 1131 s->nb_snapshots = header.nb_snapshots; 1132 1133 ret = qcow2_read_snapshots(bs); 1134 if (ret < 0) { 1135 error_setg_errno(errp, -ret, "Could not read snapshots"); 1136 goto fail; 1137 } 1138 1139 /* Clear unknown autoclear feature bits */ 1140 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { 1141 s->autoclear_features = 0; 1142 ret = qcow2_update_header(bs); 1143 if (ret < 0) { 1144 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1145 goto fail; 1146 } 1147 } 1148 1149 /* Initialise locks */ 1150 qemu_co_mutex_init(&s->lock); 1151 1152 /* Repair image if dirty */ 1153 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1154 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1155 BdrvCheckResult result = {0}; 1156 1157 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1158 if (ret < 0) { 1159 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1160 goto fail; 1161 } 1162 } 1163 1164 #ifdef DEBUG_ALLOC 1165 { 1166 BdrvCheckResult result = {0}; 1167 qcow2_check_refcounts(bs, &result, 0); 1168 } 1169 #endif 1170 return ret; 1171 1172 fail: 1173 g_free(s->unknown_header_fields); 1174 cleanup_unknown_header_ext(bs); 1175 qcow2_free_snapshots(bs); 1176 qcow2_refcount_close(bs); 1177 qemu_vfree(s->l1_table); 1178 /* else pre-write overlap checks in cache_destroy may crash */ 1179 s->l1_table = NULL; 1180 cache_clean_timer_del(bs); 1181 if (s->l2_table_cache) { 1182 qcow2_cache_destroy(bs, s->l2_table_cache); 1183 } 1184 if (s->refcount_block_cache) { 1185 qcow2_cache_destroy(bs, s->refcount_block_cache); 1186 } 1187 g_free(s->cluster_cache); 1188 qemu_vfree(s->cluster_data); 1189 return ret; 1190 } 1191 1192 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1193 { 1194 BDRVQcow2State *s = bs->opaque; 1195 1196 bs->bl.write_zeroes_alignment = s->cluster_sectors; 1197 } 1198 1199 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1200 { 1201 BDRVQcow2State *s = bs->opaque; 1202 uint8_t keybuf[16]; 1203 int len, i; 1204 Error *err = NULL; 1205 1206 memset(keybuf, 0, 16); 1207 len = strlen(key); 1208 if (len > 16) 1209 len = 16; 1210 /* XXX: we could compress the chars to 7 bits to increase 1211 entropy */ 1212 for(i = 0;i < len;i++) { 1213 keybuf[i] = key[i]; 1214 } 1215 assert(bs->encrypted); 1216 1217 qcrypto_cipher_free(s->cipher); 1218 s->cipher = qcrypto_cipher_new( 1219 QCRYPTO_CIPHER_ALG_AES_128, 1220 QCRYPTO_CIPHER_MODE_CBC, 1221 keybuf, G_N_ELEMENTS(keybuf), 1222 &err); 1223 1224 if (!s->cipher) { 1225 /* XXX would be nice if errors in this method could 1226 * be properly propagate to the caller. Would need 1227 * the bdrv_set_key() API signature to be fixed. */ 1228 error_free(err); 1229 return -1; 1230 } 1231 return 0; 1232 } 1233 1234 static int qcow2_reopen_prepare(BDRVReopenState *state, 1235 BlockReopenQueue *queue, Error **errp) 1236 { 1237 Qcow2ReopenState *r; 1238 int ret; 1239 1240 r = g_new0(Qcow2ReopenState, 1); 1241 state->opaque = r; 1242 1243 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1244 state->flags, errp); 1245 if (ret < 0) { 1246 goto fail; 1247 } 1248 1249 /* We need to write out any unwritten data if we reopen read-only. */ 1250 if ((state->flags & BDRV_O_RDWR) == 0) { 1251 ret = bdrv_flush(state->bs); 1252 if (ret < 0) { 1253 goto fail; 1254 } 1255 1256 ret = qcow2_mark_clean(state->bs); 1257 if (ret < 0) { 1258 goto fail; 1259 } 1260 } 1261 1262 return 0; 1263 1264 fail: 1265 qcow2_update_options_abort(state->bs, r); 1266 g_free(r); 1267 return ret; 1268 } 1269 1270 static void qcow2_reopen_commit(BDRVReopenState *state) 1271 { 1272 qcow2_update_options_commit(state->bs, state->opaque); 1273 g_free(state->opaque); 1274 } 1275 1276 static void qcow2_reopen_abort(BDRVReopenState *state) 1277 { 1278 qcow2_update_options_abort(state->bs, state->opaque); 1279 g_free(state->opaque); 1280 } 1281 1282 static void qcow2_join_options(QDict *options, QDict *old_options) 1283 { 1284 bool has_new_overlap_template = 1285 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1286 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1287 bool has_new_total_cache_size = 1288 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1289 bool has_all_cache_options; 1290 1291 /* New overlap template overrides all old overlap options */ 1292 if (has_new_overlap_template) { 1293 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1294 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1295 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1296 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1297 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1298 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1299 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1300 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1301 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1302 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1303 } 1304 1305 /* New total cache size overrides all old options */ 1306 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1307 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1308 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1309 } 1310 1311 qdict_join(options, old_options, false); 1312 1313 /* 1314 * If after merging all cache size options are set, an old total size is 1315 * overwritten. Do keep all options, however, if all three are new. The 1316 * resulting error message is what we want to happen. 1317 */ 1318 has_all_cache_options = 1319 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1320 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1321 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1322 1323 if (has_all_cache_options && !has_new_total_cache_size) { 1324 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1325 } 1326 } 1327 1328 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1329 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1330 { 1331 BDRVQcow2State *s = bs->opaque; 1332 uint64_t cluster_offset; 1333 int index_in_cluster, ret; 1334 int64_t status = 0; 1335 1336 *pnum = nb_sectors; 1337 qemu_co_mutex_lock(&s->lock); 1338 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); 1339 qemu_co_mutex_unlock(&s->lock); 1340 if (ret < 0) { 1341 return ret; 1342 } 1343 1344 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1345 !s->cipher) { 1346 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1347 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1348 *file = bs->file->bs; 1349 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1350 } 1351 if (ret == QCOW2_CLUSTER_ZERO) { 1352 status |= BDRV_BLOCK_ZERO; 1353 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1354 status |= BDRV_BLOCK_DATA; 1355 } 1356 return status; 1357 } 1358 1359 /* handle reading after the end of the backing file */ 1360 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1361 int64_t sector_num, int nb_sectors) 1362 { 1363 int n1; 1364 if ((sector_num + nb_sectors) <= bs->total_sectors) 1365 return nb_sectors; 1366 if (sector_num >= bs->total_sectors) 1367 n1 = 0; 1368 else 1369 n1 = bs->total_sectors - sector_num; 1370 1371 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1372 1373 return n1; 1374 } 1375 1376 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1377 int remaining_sectors, QEMUIOVector *qiov) 1378 { 1379 BDRVQcow2State *s = bs->opaque; 1380 int index_in_cluster, n1; 1381 int ret; 1382 int cur_nr_sectors; /* number of sectors in current iteration */ 1383 uint64_t cluster_offset = 0; 1384 uint64_t bytes_done = 0; 1385 QEMUIOVector hd_qiov; 1386 uint8_t *cluster_data = NULL; 1387 1388 qemu_iovec_init(&hd_qiov, qiov->niov); 1389 1390 qemu_co_mutex_lock(&s->lock); 1391 1392 while (remaining_sectors != 0) { 1393 1394 /* prepare next request */ 1395 cur_nr_sectors = remaining_sectors; 1396 if (s->cipher) { 1397 cur_nr_sectors = MIN(cur_nr_sectors, 1398 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1399 } 1400 1401 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1402 &cur_nr_sectors, &cluster_offset); 1403 if (ret < 0) { 1404 goto fail; 1405 } 1406 1407 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1408 1409 qemu_iovec_reset(&hd_qiov); 1410 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1411 cur_nr_sectors * 512); 1412 1413 switch (ret) { 1414 case QCOW2_CLUSTER_UNALLOCATED: 1415 1416 if (bs->backing) { 1417 /* read from the base image */ 1418 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1419 sector_num, cur_nr_sectors); 1420 if (n1 > 0) { 1421 QEMUIOVector local_qiov; 1422 1423 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1424 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1425 n1 * BDRV_SECTOR_SIZE); 1426 1427 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1428 qemu_co_mutex_unlock(&s->lock); 1429 ret = bdrv_co_readv(bs->backing->bs, sector_num, 1430 n1, &local_qiov); 1431 qemu_co_mutex_lock(&s->lock); 1432 1433 qemu_iovec_destroy(&local_qiov); 1434 1435 if (ret < 0) { 1436 goto fail; 1437 } 1438 } 1439 } else { 1440 /* Note: in this case, no need to wait */ 1441 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1442 } 1443 break; 1444 1445 case QCOW2_CLUSTER_ZERO: 1446 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1447 break; 1448 1449 case QCOW2_CLUSTER_COMPRESSED: 1450 /* add AIO support for compressed blocks ? */ 1451 ret = qcow2_decompress_cluster(bs, cluster_offset); 1452 if (ret < 0) { 1453 goto fail; 1454 } 1455 1456 qemu_iovec_from_buf(&hd_qiov, 0, 1457 s->cluster_cache + index_in_cluster * 512, 1458 512 * cur_nr_sectors); 1459 break; 1460 1461 case QCOW2_CLUSTER_NORMAL: 1462 if ((cluster_offset & 511) != 0) { 1463 ret = -EIO; 1464 goto fail; 1465 } 1466 1467 if (bs->encrypted) { 1468 assert(s->cipher); 1469 1470 /* 1471 * For encrypted images, read everything into a temporary 1472 * contiguous buffer on which the AES functions can work. 1473 */ 1474 if (!cluster_data) { 1475 cluster_data = 1476 qemu_try_blockalign(bs->file->bs, 1477 QCOW_MAX_CRYPT_CLUSTERS 1478 * s->cluster_size); 1479 if (cluster_data == NULL) { 1480 ret = -ENOMEM; 1481 goto fail; 1482 } 1483 } 1484 1485 assert(cur_nr_sectors <= 1486 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1487 qemu_iovec_reset(&hd_qiov); 1488 qemu_iovec_add(&hd_qiov, cluster_data, 1489 512 * cur_nr_sectors); 1490 } 1491 1492 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1493 qemu_co_mutex_unlock(&s->lock); 1494 ret = bdrv_co_readv(bs->file->bs, 1495 (cluster_offset >> 9) + index_in_cluster, 1496 cur_nr_sectors, &hd_qiov); 1497 qemu_co_mutex_lock(&s->lock); 1498 if (ret < 0) { 1499 goto fail; 1500 } 1501 if (bs->encrypted) { 1502 assert(s->cipher); 1503 Error *err = NULL; 1504 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1505 cluster_data, cur_nr_sectors, false, 1506 &err) < 0) { 1507 error_free(err); 1508 ret = -EIO; 1509 goto fail; 1510 } 1511 qemu_iovec_from_buf(qiov, bytes_done, 1512 cluster_data, 512 * cur_nr_sectors); 1513 } 1514 break; 1515 1516 default: 1517 g_assert_not_reached(); 1518 ret = -EIO; 1519 goto fail; 1520 } 1521 1522 remaining_sectors -= cur_nr_sectors; 1523 sector_num += cur_nr_sectors; 1524 bytes_done += cur_nr_sectors * 512; 1525 } 1526 ret = 0; 1527 1528 fail: 1529 qemu_co_mutex_unlock(&s->lock); 1530 1531 qemu_iovec_destroy(&hd_qiov); 1532 qemu_vfree(cluster_data); 1533 1534 return ret; 1535 } 1536 1537 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1538 int64_t sector_num, 1539 int remaining_sectors, 1540 QEMUIOVector *qiov) 1541 { 1542 BDRVQcow2State *s = bs->opaque; 1543 int index_in_cluster; 1544 int ret; 1545 int cur_nr_sectors; /* number of sectors in current iteration */ 1546 uint64_t cluster_offset; 1547 QEMUIOVector hd_qiov; 1548 uint64_t bytes_done = 0; 1549 uint8_t *cluster_data = NULL; 1550 QCowL2Meta *l2meta = NULL; 1551 1552 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1553 remaining_sectors); 1554 1555 qemu_iovec_init(&hd_qiov, qiov->niov); 1556 1557 s->cluster_cache_offset = -1; /* disable compressed cache */ 1558 1559 qemu_co_mutex_lock(&s->lock); 1560 1561 while (remaining_sectors != 0) { 1562 1563 l2meta = NULL; 1564 1565 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1566 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1567 cur_nr_sectors = remaining_sectors; 1568 if (bs->encrypted && 1569 cur_nr_sectors > 1570 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1571 cur_nr_sectors = 1572 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1573 } 1574 1575 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1576 &cur_nr_sectors, &cluster_offset, &l2meta); 1577 if (ret < 0) { 1578 goto fail; 1579 } 1580 1581 assert((cluster_offset & 511) == 0); 1582 1583 qemu_iovec_reset(&hd_qiov); 1584 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1585 cur_nr_sectors * 512); 1586 1587 if (bs->encrypted) { 1588 Error *err = NULL; 1589 assert(s->cipher); 1590 if (!cluster_data) { 1591 cluster_data = qemu_try_blockalign(bs->file->bs, 1592 QCOW_MAX_CRYPT_CLUSTERS 1593 * s->cluster_size); 1594 if (cluster_data == NULL) { 1595 ret = -ENOMEM; 1596 goto fail; 1597 } 1598 } 1599 1600 assert(hd_qiov.size <= 1601 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1602 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1603 1604 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1605 cluster_data, cur_nr_sectors, 1606 true, &err) < 0) { 1607 error_free(err); 1608 ret = -EIO; 1609 goto fail; 1610 } 1611 1612 qemu_iovec_reset(&hd_qiov); 1613 qemu_iovec_add(&hd_qiov, cluster_data, 1614 cur_nr_sectors * 512); 1615 } 1616 1617 ret = qcow2_pre_write_overlap_check(bs, 0, 1618 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1619 cur_nr_sectors * BDRV_SECTOR_SIZE); 1620 if (ret < 0) { 1621 goto fail; 1622 } 1623 1624 qemu_co_mutex_unlock(&s->lock); 1625 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1626 trace_qcow2_writev_data(qemu_coroutine_self(), 1627 (cluster_offset >> 9) + index_in_cluster); 1628 ret = bdrv_co_writev(bs->file->bs, 1629 (cluster_offset >> 9) + index_in_cluster, 1630 cur_nr_sectors, &hd_qiov); 1631 qemu_co_mutex_lock(&s->lock); 1632 if (ret < 0) { 1633 goto fail; 1634 } 1635 1636 while (l2meta != NULL) { 1637 QCowL2Meta *next; 1638 1639 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1640 if (ret < 0) { 1641 goto fail; 1642 } 1643 1644 /* Take the request off the list of running requests */ 1645 if (l2meta->nb_clusters != 0) { 1646 QLIST_REMOVE(l2meta, next_in_flight); 1647 } 1648 1649 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1650 1651 next = l2meta->next; 1652 g_free(l2meta); 1653 l2meta = next; 1654 } 1655 1656 remaining_sectors -= cur_nr_sectors; 1657 sector_num += cur_nr_sectors; 1658 bytes_done += cur_nr_sectors * 512; 1659 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1660 } 1661 ret = 0; 1662 1663 fail: 1664 qemu_co_mutex_unlock(&s->lock); 1665 1666 while (l2meta != NULL) { 1667 QCowL2Meta *next; 1668 1669 if (l2meta->nb_clusters != 0) { 1670 QLIST_REMOVE(l2meta, next_in_flight); 1671 } 1672 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1673 1674 next = l2meta->next; 1675 g_free(l2meta); 1676 l2meta = next; 1677 } 1678 1679 qemu_iovec_destroy(&hd_qiov); 1680 qemu_vfree(cluster_data); 1681 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1682 1683 return ret; 1684 } 1685 1686 static int qcow2_inactivate(BlockDriverState *bs) 1687 { 1688 BDRVQcow2State *s = bs->opaque; 1689 int ret, result = 0; 1690 1691 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1692 if (ret) { 1693 result = ret; 1694 error_report("Failed to flush the L2 table cache: %s", 1695 strerror(-ret)); 1696 } 1697 1698 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1699 if (ret) { 1700 result = ret; 1701 error_report("Failed to flush the refcount block cache: %s", 1702 strerror(-ret)); 1703 } 1704 1705 if (result == 0) { 1706 qcow2_mark_clean(bs); 1707 } 1708 1709 return result; 1710 } 1711 1712 static void qcow2_close(BlockDriverState *bs) 1713 { 1714 BDRVQcow2State *s = bs->opaque; 1715 qemu_vfree(s->l1_table); 1716 /* else pre-write overlap checks in cache_destroy may crash */ 1717 s->l1_table = NULL; 1718 1719 if (!(s->flags & BDRV_O_INACTIVE)) { 1720 qcow2_inactivate(bs); 1721 } 1722 1723 cache_clean_timer_del(bs); 1724 qcow2_cache_destroy(bs, s->l2_table_cache); 1725 qcow2_cache_destroy(bs, s->refcount_block_cache); 1726 1727 qcrypto_cipher_free(s->cipher); 1728 s->cipher = NULL; 1729 1730 g_free(s->unknown_header_fields); 1731 cleanup_unknown_header_ext(bs); 1732 1733 g_free(s->image_backing_file); 1734 g_free(s->image_backing_format); 1735 1736 g_free(s->cluster_cache); 1737 qemu_vfree(s->cluster_data); 1738 qcow2_refcount_close(bs); 1739 qcow2_free_snapshots(bs); 1740 } 1741 1742 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1743 { 1744 BDRVQcow2State *s = bs->opaque; 1745 int flags = s->flags; 1746 QCryptoCipher *cipher = NULL; 1747 QDict *options; 1748 Error *local_err = NULL; 1749 int ret; 1750 1751 /* 1752 * Backing files are read-only which makes all of their metadata immutable, 1753 * that means we don't have to worry about reopening them here. 1754 */ 1755 1756 cipher = s->cipher; 1757 s->cipher = NULL; 1758 1759 qcow2_close(bs); 1760 1761 memset(s, 0, sizeof(BDRVQcow2State)); 1762 options = qdict_clone_shallow(bs->options); 1763 1764 flags &= ~BDRV_O_INACTIVE; 1765 ret = qcow2_open(bs, options, flags, &local_err); 1766 QDECREF(options); 1767 if (local_err) { 1768 error_propagate(errp, local_err); 1769 error_prepend(errp, "Could not reopen qcow2 layer: "); 1770 bs->drv = NULL; 1771 return; 1772 } else if (ret < 0) { 1773 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1774 bs->drv = NULL; 1775 return; 1776 } 1777 1778 s->cipher = cipher; 1779 } 1780 1781 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1782 size_t len, size_t buflen) 1783 { 1784 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1785 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1786 1787 if (buflen < ext_len) { 1788 return -ENOSPC; 1789 } 1790 1791 *ext_backing_fmt = (QCowExtension) { 1792 .magic = cpu_to_be32(magic), 1793 .len = cpu_to_be32(len), 1794 }; 1795 memcpy(buf + sizeof(QCowExtension), s, len); 1796 1797 return ext_len; 1798 } 1799 1800 /* 1801 * Updates the qcow2 header, including the variable length parts of it, i.e. 1802 * the backing file name and all extensions. qcow2 was not designed to allow 1803 * such changes, so if we run out of space (we can only use the first cluster) 1804 * this function may fail. 1805 * 1806 * Returns 0 on success, -errno in error cases. 1807 */ 1808 int qcow2_update_header(BlockDriverState *bs) 1809 { 1810 BDRVQcow2State *s = bs->opaque; 1811 QCowHeader *header; 1812 char *buf; 1813 size_t buflen = s->cluster_size; 1814 int ret; 1815 uint64_t total_size; 1816 uint32_t refcount_table_clusters; 1817 size_t header_length; 1818 Qcow2UnknownHeaderExtension *uext; 1819 1820 buf = qemu_blockalign(bs, buflen); 1821 1822 /* Header structure */ 1823 header = (QCowHeader*) buf; 1824 1825 if (buflen < sizeof(*header)) { 1826 ret = -ENOSPC; 1827 goto fail; 1828 } 1829 1830 header_length = sizeof(*header) + s->unknown_header_fields_size; 1831 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1832 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1833 1834 *header = (QCowHeader) { 1835 /* Version 2 fields */ 1836 .magic = cpu_to_be32(QCOW_MAGIC), 1837 .version = cpu_to_be32(s->qcow_version), 1838 .backing_file_offset = 0, 1839 .backing_file_size = 0, 1840 .cluster_bits = cpu_to_be32(s->cluster_bits), 1841 .size = cpu_to_be64(total_size), 1842 .crypt_method = cpu_to_be32(s->crypt_method_header), 1843 .l1_size = cpu_to_be32(s->l1_size), 1844 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1845 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1846 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1847 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1848 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1849 1850 /* Version 3 fields */ 1851 .incompatible_features = cpu_to_be64(s->incompatible_features), 1852 .compatible_features = cpu_to_be64(s->compatible_features), 1853 .autoclear_features = cpu_to_be64(s->autoclear_features), 1854 .refcount_order = cpu_to_be32(s->refcount_order), 1855 .header_length = cpu_to_be32(header_length), 1856 }; 1857 1858 /* For older versions, write a shorter header */ 1859 switch (s->qcow_version) { 1860 case 2: 1861 ret = offsetof(QCowHeader, incompatible_features); 1862 break; 1863 case 3: 1864 ret = sizeof(*header); 1865 break; 1866 default: 1867 ret = -EINVAL; 1868 goto fail; 1869 } 1870 1871 buf += ret; 1872 buflen -= ret; 1873 memset(buf, 0, buflen); 1874 1875 /* Preserve any unknown field in the header */ 1876 if (s->unknown_header_fields_size) { 1877 if (buflen < s->unknown_header_fields_size) { 1878 ret = -ENOSPC; 1879 goto fail; 1880 } 1881 1882 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1883 buf += s->unknown_header_fields_size; 1884 buflen -= s->unknown_header_fields_size; 1885 } 1886 1887 /* Backing file format header extension */ 1888 if (s->image_backing_format) { 1889 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1890 s->image_backing_format, 1891 strlen(s->image_backing_format), 1892 buflen); 1893 if (ret < 0) { 1894 goto fail; 1895 } 1896 1897 buf += ret; 1898 buflen -= ret; 1899 } 1900 1901 /* Feature table */ 1902 if (s->qcow_version >= 3) { 1903 Qcow2Feature features[] = { 1904 { 1905 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1906 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1907 .name = "dirty bit", 1908 }, 1909 { 1910 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1911 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1912 .name = "corrupt bit", 1913 }, 1914 { 1915 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1916 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1917 .name = "lazy refcounts", 1918 }, 1919 }; 1920 1921 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1922 features, sizeof(features), buflen); 1923 if (ret < 0) { 1924 goto fail; 1925 } 1926 buf += ret; 1927 buflen -= ret; 1928 } 1929 1930 /* Keep unknown header extensions */ 1931 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1932 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1933 if (ret < 0) { 1934 goto fail; 1935 } 1936 1937 buf += ret; 1938 buflen -= ret; 1939 } 1940 1941 /* End of header extensions */ 1942 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1943 if (ret < 0) { 1944 goto fail; 1945 } 1946 1947 buf += ret; 1948 buflen -= ret; 1949 1950 /* Backing file name */ 1951 if (s->image_backing_file) { 1952 size_t backing_file_len = strlen(s->image_backing_file); 1953 1954 if (buflen < backing_file_len) { 1955 ret = -ENOSPC; 1956 goto fail; 1957 } 1958 1959 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1960 strncpy(buf, s->image_backing_file, buflen); 1961 1962 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1963 header->backing_file_size = cpu_to_be32(backing_file_len); 1964 } 1965 1966 /* Write the new header */ 1967 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size); 1968 if (ret < 0) { 1969 goto fail; 1970 } 1971 1972 ret = 0; 1973 fail: 1974 qemu_vfree(header); 1975 return ret; 1976 } 1977 1978 static int qcow2_change_backing_file(BlockDriverState *bs, 1979 const char *backing_file, const char *backing_fmt) 1980 { 1981 BDRVQcow2State *s = bs->opaque; 1982 1983 if (backing_file && strlen(backing_file) > 1023) { 1984 return -EINVAL; 1985 } 1986 1987 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1988 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1989 1990 g_free(s->image_backing_file); 1991 g_free(s->image_backing_format); 1992 1993 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 1994 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 1995 1996 return qcow2_update_header(bs); 1997 } 1998 1999 static int preallocate(BlockDriverState *bs) 2000 { 2001 uint64_t nb_sectors; 2002 uint64_t offset; 2003 uint64_t host_offset = 0; 2004 int num; 2005 int ret; 2006 QCowL2Meta *meta; 2007 2008 nb_sectors = bdrv_nb_sectors(bs); 2009 offset = 0; 2010 2011 while (nb_sectors) { 2012 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 2013 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 2014 &host_offset, &meta); 2015 if (ret < 0) { 2016 return ret; 2017 } 2018 2019 while (meta) { 2020 QCowL2Meta *next = meta->next; 2021 2022 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2023 if (ret < 0) { 2024 qcow2_free_any_clusters(bs, meta->alloc_offset, 2025 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2026 return ret; 2027 } 2028 2029 /* There are no dependent requests, but we need to remove our 2030 * request from the list of in-flight requests */ 2031 QLIST_REMOVE(meta, next_in_flight); 2032 2033 g_free(meta); 2034 meta = next; 2035 } 2036 2037 /* TODO Preallocate data if requested */ 2038 2039 nb_sectors -= num; 2040 offset += num << BDRV_SECTOR_BITS; 2041 } 2042 2043 /* 2044 * It is expected that the image file is large enough to actually contain 2045 * all of the allocated clusters (otherwise we get failing reads after 2046 * EOF). Extend the image to the last allocated sector. 2047 */ 2048 if (host_offset != 0) { 2049 uint8_t buf[BDRV_SECTOR_SIZE]; 2050 memset(buf, 0, BDRV_SECTOR_SIZE); 2051 ret = bdrv_write(bs->file->bs, 2052 (host_offset >> BDRV_SECTOR_BITS) + num - 1, 2053 buf, 1); 2054 if (ret < 0) { 2055 return ret; 2056 } 2057 } 2058 2059 return 0; 2060 } 2061 2062 static int qcow2_create2(const char *filename, int64_t total_size, 2063 const char *backing_file, const char *backing_format, 2064 int flags, size_t cluster_size, PreallocMode prealloc, 2065 QemuOpts *opts, int version, int refcount_order, 2066 Error **errp) 2067 { 2068 int cluster_bits; 2069 QDict *options; 2070 2071 /* Calculate cluster_bits */ 2072 cluster_bits = ctz32(cluster_size); 2073 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2074 (1 << cluster_bits) != cluster_size) 2075 { 2076 error_setg(errp, "Cluster size must be a power of two between %d and " 2077 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2078 return -EINVAL; 2079 } 2080 2081 /* 2082 * Open the image file and write a minimal qcow2 header. 2083 * 2084 * We keep things simple and start with a zero-sized image. We also 2085 * do without refcount blocks or a L1 table for now. We'll fix the 2086 * inconsistency later. 2087 * 2088 * We do need a refcount table because growing the refcount table means 2089 * allocating two new refcount blocks - the seconds of which would be at 2090 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2091 * size for any qcow2 image. 2092 */ 2093 BlockBackend *blk; 2094 QCowHeader *header; 2095 uint64_t* refcount_table; 2096 Error *local_err = NULL; 2097 int ret; 2098 2099 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2100 /* Note: The following calculation does not need to be exact; if it is a 2101 * bit off, either some bytes will be "leaked" (which is fine) or we 2102 * will need to increase the file size by some bytes (which is fine, 2103 * too, as long as the bulk is allocated here). Therefore, using 2104 * floating point arithmetic is fine. */ 2105 int64_t meta_size = 0; 2106 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2107 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2108 int refblock_bits, refblock_size; 2109 /* refcount entry size in bytes */ 2110 double rces = (1 << refcount_order) / 8.; 2111 2112 /* see qcow2_open() */ 2113 refblock_bits = cluster_bits - (refcount_order - 3); 2114 refblock_size = 1 << refblock_bits; 2115 2116 /* header: 1 cluster */ 2117 meta_size += cluster_size; 2118 2119 /* total size of L2 tables */ 2120 nl2e = aligned_total_size / cluster_size; 2121 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2122 meta_size += nl2e * sizeof(uint64_t); 2123 2124 /* total size of L1 tables */ 2125 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2126 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2127 meta_size += nl1e * sizeof(uint64_t); 2128 2129 /* total size of refcount blocks 2130 * 2131 * note: every host cluster is reference-counted, including metadata 2132 * (even refcount blocks are recursively included). 2133 * Let: 2134 * a = total_size (this is the guest disk size) 2135 * m = meta size not including refcount blocks and refcount tables 2136 * c = cluster size 2137 * y1 = number of refcount blocks entries 2138 * y2 = meta size including everything 2139 * rces = refcount entry size in bytes 2140 * then, 2141 * y1 = (y2 + a)/c 2142 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2143 * we can get y1: 2144 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2145 */ 2146 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2147 / (cluster_size - rces - rces * sizeof(uint64_t) 2148 / cluster_size); 2149 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2150 2151 /* total size of refcount tables */ 2152 nreftablee = nrefblocke / refblock_size; 2153 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2154 meta_size += nreftablee * sizeof(uint64_t); 2155 2156 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2157 aligned_total_size + meta_size, &error_abort); 2158 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2159 &error_abort); 2160 } 2161 2162 ret = bdrv_create_file(filename, opts, &local_err); 2163 if (ret < 0) { 2164 error_propagate(errp, local_err); 2165 return ret; 2166 } 2167 2168 blk = blk_new_open(filename, NULL, NULL, 2169 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); 2170 if (blk == NULL) { 2171 error_propagate(errp, local_err); 2172 return -EIO; 2173 } 2174 2175 blk_set_allow_write_beyond_eof(blk, true); 2176 2177 /* Write the header */ 2178 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2179 header = g_malloc0(cluster_size); 2180 *header = (QCowHeader) { 2181 .magic = cpu_to_be32(QCOW_MAGIC), 2182 .version = cpu_to_be32(version), 2183 .cluster_bits = cpu_to_be32(cluster_bits), 2184 .size = cpu_to_be64(0), 2185 .l1_table_offset = cpu_to_be64(0), 2186 .l1_size = cpu_to_be32(0), 2187 .refcount_table_offset = cpu_to_be64(cluster_size), 2188 .refcount_table_clusters = cpu_to_be32(1), 2189 .refcount_order = cpu_to_be32(refcount_order), 2190 .header_length = cpu_to_be32(sizeof(*header)), 2191 }; 2192 2193 if (flags & BLOCK_FLAG_ENCRYPT) { 2194 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2195 } else { 2196 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2197 } 2198 2199 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2200 header->compatible_features |= 2201 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2202 } 2203 2204 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2205 g_free(header); 2206 if (ret < 0) { 2207 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2208 goto out; 2209 } 2210 2211 /* Write a refcount table with one refcount block */ 2212 refcount_table = g_malloc0(2 * cluster_size); 2213 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2214 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2215 g_free(refcount_table); 2216 2217 if (ret < 0) { 2218 error_setg_errno(errp, -ret, "Could not write refcount table"); 2219 goto out; 2220 } 2221 2222 blk_unref(blk); 2223 blk = NULL; 2224 2225 /* 2226 * And now open the image and make it consistent first (i.e. increase the 2227 * refcount of the cluster that is occupied by the header and the refcount 2228 * table) 2229 */ 2230 options = qdict_new(); 2231 qdict_put(options, "driver", qstring_from_str("qcow2")); 2232 blk = blk_new_open(filename, NULL, options, 2233 BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err); 2234 if (blk == NULL) { 2235 error_propagate(errp, local_err); 2236 ret = -EIO; 2237 goto out; 2238 } 2239 2240 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2241 if (ret < 0) { 2242 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2243 "header and refcount table"); 2244 goto out; 2245 2246 } else if (ret != 0) { 2247 error_report("Huh, first cluster in empty image is already in use?"); 2248 abort(); 2249 } 2250 2251 /* Create a full header (including things like feature table) */ 2252 ret = qcow2_update_header(blk_bs(blk)); 2253 if (ret < 0) { 2254 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2255 goto out; 2256 } 2257 2258 /* Okay, now that we have a valid image, let's give it the right size */ 2259 ret = blk_truncate(blk, total_size); 2260 if (ret < 0) { 2261 error_setg_errno(errp, -ret, "Could not resize image"); 2262 goto out; 2263 } 2264 2265 /* Want a backing file? There you go.*/ 2266 if (backing_file) { 2267 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2268 if (ret < 0) { 2269 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2270 "with format '%s'", backing_file, backing_format); 2271 goto out; 2272 } 2273 } 2274 2275 /* And if we're supposed to preallocate metadata, do that now */ 2276 if (prealloc != PREALLOC_MODE_OFF) { 2277 BDRVQcow2State *s = blk_bs(blk)->opaque; 2278 qemu_co_mutex_lock(&s->lock); 2279 ret = preallocate(blk_bs(blk)); 2280 qemu_co_mutex_unlock(&s->lock); 2281 if (ret < 0) { 2282 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2283 goto out; 2284 } 2285 } 2286 2287 blk_unref(blk); 2288 blk = NULL; 2289 2290 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2291 options = qdict_new(); 2292 qdict_put(options, "driver", qstring_from_str("qcow2")); 2293 blk = blk_new_open(filename, NULL, options, 2294 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err); 2295 if (blk == NULL) { 2296 error_propagate(errp, local_err); 2297 ret = -EIO; 2298 goto out; 2299 } 2300 2301 ret = 0; 2302 out: 2303 if (blk) { 2304 blk_unref(blk); 2305 } 2306 return ret; 2307 } 2308 2309 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2310 { 2311 char *backing_file = NULL; 2312 char *backing_fmt = NULL; 2313 char *buf = NULL; 2314 uint64_t size = 0; 2315 int flags = 0; 2316 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2317 PreallocMode prealloc; 2318 int version = 3; 2319 uint64_t refcount_bits = 16; 2320 int refcount_order; 2321 Error *local_err = NULL; 2322 int ret; 2323 2324 /* Read out options */ 2325 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2326 BDRV_SECTOR_SIZE); 2327 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2328 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2329 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2330 flags |= BLOCK_FLAG_ENCRYPT; 2331 } 2332 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2333 DEFAULT_CLUSTER_SIZE); 2334 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2335 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2336 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2337 &local_err); 2338 if (local_err) { 2339 error_propagate(errp, local_err); 2340 ret = -EINVAL; 2341 goto finish; 2342 } 2343 g_free(buf); 2344 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2345 if (!buf) { 2346 /* keep the default */ 2347 } else if (!strcmp(buf, "0.10")) { 2348 version = 2; 2349 } else if (!strcmp(buf, "1.1")) { 2350 version = 3; 2351 } else { 2352 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2353 ret = -EINVAL; 2354 goto finish; 2355 } 2356 2357 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2358 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2359 } 2360 2361 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2362 error_setg(errp, "Backing file and preallocation cannot be used at " 2363 "the same time"); 2364 ret = -EINVAL; 2365 goto finish; 2366 } 2367 2368 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2369 error_setg(errp, "Lazy refcounts only supported with compatibility " 2370 "level 1.1 and above (use compat=1.1 or greater)"); 2371 ret = -EINVAL; 2372 goto finish; 2373 } 2374 2375 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2376 refcount_bits); 2377 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2378 error_setg(errp, "Refcount width must be a power of two and may not " 2379 "exceed 64 bits"); 2380 ret = -EINVAL; 2381 goto finish; 2382 } 2383 2384 if (version < 3 && refcount_bits != 16) { 2385 error_setg(errp, "Different refcount widths than 16 bits require " 2386 "compatibility level 1.1 or above (use compat=1.1 or " 2387 "greater)"); 2388 ret = -EINVAL; 2389 goto finish; 2390 } 2391 2392 refcount_order = ctz32(refcount_bits); 2393 2394 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2395 cluster_size, prealloc, opts, version, refcount_order, 2396 &local_err); 2397 if (local_err) { 2398 error_propagate(errp, local_err); 2399 } 2400 2401 finish: 2402 g_free(backing_file); 2403 g_free(backing_fmt); 2404 g_free(buf); 2405 return ret; 2406 } 2407 2408 2409 static bool is_zero_cluster(BlockDriverState *bs, int64_t start) 2410 { 2411 BDRVQcow2State *s = bs->opaque; 2412 int nr; 2413 BlockDriverState *file; 2414 int64_t res = bdrv_get_block_status_above(bs, NULL, start, 2415 s->cluster_sectors, &nr, &file); 2416 return res >= 0 && ((res & BDRV_BLOCK_ZERO) || !(res & BDRV_BLOCK_DATA)); 2417 } 2418 2419 static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start) 2420 { 2421 BDRVQcow2State *s = bs->opaque; 2422 int nr = s->cluster_sectors; 2423 uint64_t off; 2424 int ret; 2425 2426 ret = qcow2_get_cluster_offset(bs, start << BDRV_SECTOR_BITS, &nr, &off); 2427 return ret == QCOW2_CLUSTER_UNALLOCATED || ret == QCOW2_CLUSTER_ZERO; 2428 } 2429 2430 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2431 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2432 { 2433 int ret; 2434 BDRVQcow2State *s = bs->opaque; 2435 2436 int head = sector_num % s->cluster_sectors; 2437 int tail = (sector_num + nb_sectors) % s->cluster_sectors; 2438 2439 if (head != 0 || tail != 0) { 2440 int64_t cl_end = -1; 2441 2442 sector_num -= head; 2443 nb_sectors += head; 2444 2445 if (tail != 0) { 2446 nb_sectors += s->cluster_sectors - tail; 2447 } 2448 2449 if (!is_zero_cluster(bs, sector_num)) { 2450 return -ENOTSUP; 2451 } 2452 2453 if (nb_sectors > s->cluster_sectors) { 2454 /* Technically the request can cover 2 clusters, f.e. 4k write 2455 at s->cluster_sectors - 2k offset. One of these cluster can 2456 be zeroed, one unallocated */ 2457 cl_end = sector_num + nb_sectors - s->cluster_sectors; 2458 if (!is_zero_cluster(bs, cl_end)) { 2459 return -ENOTSUP; 2460 } 2461 } 2462 2463 qemu_co_mutex_lock(&s->lock); 2464 /* We can have new write after previous check */ 2465 if (!is_zero_cluster_top_locked(bs, sector_num) || 2466 (cl_end > 0 && !is_zero_cluster_top_locked(bs, cl_end))) { 2467 qemu_co_mutex_unlock(&s->lock); 2468 return -ENOTSUP; 2469 } 2470 } else { 2471 qemu_co_mutex_lock(&s->lock); 2472 } 2473 2474 /* Whatever is left can use real zero clusters */ 2475 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, nb_sectors); 2476 qemu_co_mutex_unlock(&s->lock); 2477 2478 return ret; 2479 } 2480 2481 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2482 int64_t sector_num, int nb_sectors) 2483 { 2484 int ret; 2485 BDRVQcow2State *s = bs->opaque; 2486 2487 qemu_co_mutex_lock(&s->lock); 2488 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2489 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2490 qemu_co_mutex_unlock(&s->lock); 2491 return ret; 2492 } 2493 2494 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2495 { 2496 BDRVQcow2State *s = bs->opaque; 2497 int64_t new_l1_size; 2498 int ret; 2499 2500 if (offset & 511) { 2501 error_report("The new size must be a multiple of 512"); 2502 return -EINVAL; 2503 } 2504 2505 /* cannot proceed if image has snapshots */ 2506 if (s->nb_snapshots) { 2507 error_report("Can't resize an image which has snapshots"); 2508 return -ENOTSUP; 2509 } 2510 2511 /* shrinking is currently not supported */ 2512 if (offset < bs->total_sectors * 512) { 2513 error_report("qcow2 doesn't support shrinking images yet"); 2514 return -ENOTSUP; 2515 } 2516 2517 new_l1_size = size_to_l1(s, offset); 2518 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2519 if (ret < 0) { 2520 return ret; 2521 } 2522 2523 /* write updated header.size */ 2524 offset = cpu_to_be64(offset); 2525 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), 2526 &offset, sizeof(uint64_t)); 2527 if (ret < 0) { 2528 return ret; 2529 } 2530 2531 s->l1_vm_state_index = new_l1_size; 2532 return 0; 2533 } 2534 2535 /* XXX: put compressed sectors first, then all the cluster aligned 2536 tables to avoid losing bytes in alignment */ 2537 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2538 const uint8_t *buf, int nb_sectors) 2539 { 2540 BDRVQcow2State *s = bs->opaque; 2541 z_stream strm; 2542 int ret, out_len; 2543 uint8_t *out_buf; 2544 uint64_t cluster_offset; 2545 2546 if (nb_sectors == 0) { 2547 /* align end of file to a sector boundary to ease reading with 2548 sector based I/Os */ 2549 cluster_offset = bdrv_getlength(bs->file->bs); 2550 return bdrv_truncate(bs->file->bs, cluster_offset); 2551 } 2552 2553 if (nb_sectors != s->cluster_sectors) { 2554 ret = -EINVAL; 2555 2556 /* Zero-pad last write if image size is not cluster aligned */ 2557 if (sector_num + nb_sectors == bs->total_sectors && 2558 nb_sectors < s->cluster_sectors) { 2559 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2560 memset(pad_buf, 0, s->cluster_size); 2561 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2562 ret = qcow2_write_compressed(bs, sector_num, 2563 pad_buf, s->cluster_sectors); 2564 qemu_vfree(pad_buf); 2565 } 2566 return ret; 2567 } 2568 2569 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2570 2571 /* best compression, small window, no zlib header */ 2572 memset(&strm, 0, sizeof(strm)); 2573 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2574 Z_DEFLATED, -12, 2575 9, Z_DEFAULT_STRATEGY); 2576 if (ret != 0) { 2577 ret = -EINVAL; 2578 goto fail; 2579 } 2580 2581 strm.avail_in = s->cluster_size; 2582 strm.next_in = (uint8_t *)buf; 2583 strm.avail_out = s->cluster_size; 2584 strm.next_out = out_buf; 2585 2586 ret = deflate(&strm, Z_FINISH); 2587 if (ret != Z_STREAM_END && ret != Z_OK) { 2588 deflateEnd(&strm); 2589 ret = -EINVAL; 2590 goto fail; 2591 } 2592 out_len = strm.next_out - out_buf; 2593 2594 deflateEnd(&strm); 2595 2596 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2597 /* could not compress: write normal cluster */ 2598 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2599 if (ret < 0) { 2600 goto fail; 2601 } 2602 } else { 2603 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2604 sector_num << 9, out_len); 2605 if (!cluster_offset) { 2606 ret = -EIO; 2607 goto fail; 2608 } 2609 cluster_offset &= s->cluster_offset_mask; 2610 2611 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2612 if (ret < 0) { 2613 goto fail; 2614 } 2615 2616 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2617 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 2618 if (ret < 0) { 2619 goto fail; 2620 } 2621 } 2622 2623 ret = 0; 2624 fail: 2625 g_free(out_buf); 2626 return ret; 2627 } 2628 2629 static int make_completely_empty(BlockDriverState *bs) 2630 { 2631 BDRVQcow2State *s = bs->opaque; 2632 int ret, l1_clusters; 2633 int64_t offset; 2634 uint64_t *new_reftable = NULL; 2635 uint64_t rt_entry, l1_size2; 2636 struct { 2637 uint64_t l1_offset; 2638 uint64_t reftable_offset; 2639 uint32_t reftable_clusters; 2640 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2641 2642 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2643 if (ret < 0) { 2644 goto fail; 2645 } 2646 2647 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2648 if (ret < 0) { 2649 goto fail; 2650 } 2651 2652 /* Refcounts will be broken utterly */ 2653 ret = qcow2_mark_dirty(bs); 2654 if (ret < 0) { 2655 goto fail; 2656 } 2657 2658 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2659 2660 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2661 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2662 2663 /* After this call, neither the in-memory nor the on-disk refcount 2664 * information accurately describe the actual references */ 2665 2666 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, 2667 l1_clusters * s->cluster_sectors, 0); 2668 if (ret < 0) { 2669 goto fail_broken_refcounts; 2670 } 2671 memset(s->l1_table, 0, l1_size2); 2672 2673 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2674 2675 /* Overwrite enough clusters at the beginning of the sectors to place 2676 * the refcount table, a refcount block and the L1 table in; this may 2677 * overwrite parts of the existing refcount and L1 table, which is not 2678 * an issue because the dirty flag is set, complete data loss is in fact 2679 * desired and partial data loss is consequently fine as well */ 2680 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, 2681 (2 + l1_clusters) * s->cluster_size / 2682 BDRV_SECTOR_SIZE, 0); 2683 /* This call (even if it failed overall) may have overwritten on-disk 2684 * refcount structures; in that case, the in-memory refcount information 2685 * will probably differ from the on-disk information which makes the BDS 2686 * unusable */ 2687 if (ret < 0) { 2688 goto fail_broken_refcounts; 2689 } 2690 2691 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2692 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2693 2694 /* "Create" an empty reftable (one cluster) directly after the image 2695 * header and an empty L1 table three clusters after the image header; 2696 * the cluster between those two will be used as the first refblock */ 2697 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2698 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2699 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2700 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset), 2701 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2702 if (ret < 0) { 2703 goto fail_broken_refcounts; 2704 } 2705 2706 s->l1_table_offset = 3 * s->cluster_size; 2707 2708 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2709 if (!new_reftable) { 2710 ret = -ENOMEM; 2711 goto fail_broken_refcounts; 2712 } 2713 2714 s->refcount_table_offset = s->cluster_size; 2715 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2716 2717 g_free(s->refcount_table); 2718 s->refcount_table = new_reftable; 2719 new_reftable = NULL; 2720 2721 /* Now the in-memory refcount information again corresponds to the on-disk 2722 * information (reftable is empty and no refblocks (the refblock cache is 2723 * empty)); however, this means some clusters (e.g. the image header) are 2724 * referenced, but not refcounted, but the normal qcow2 code assumes that 2725 * the in-memory information is always correct */ 2726 2727 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2728 2729 /* Enter the first refblock into the reftable */ 2730 rt_entry = cpu_to_be64(2 * s->cluster_size); 2731 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size, 2732 &rt_entry, sizeof(rt_entry)); 2733 if (ret < 0) { 2734 goto fail_broken_refcounts; 2735 } 2736 s->refcount_table[0] = 2 * s->cluster_size; 2737 2738 s->free_cluster_index = 0; 2739 assert(3 + l1_clusters <= s->refcount_block_size); 2740 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2741 if (offset < 0) { 2742 ret = offset; 2743 goto fail_broken_refcounts; 2744 } else if (offset > 0) { 2745 error_report("First cluster in emptied image is in use"); 2746 abort(); 2747 } 2748 2749 /* Now finally the in-memory information corresponds to the on-disk 2750 * structures and is correct */ 2751 ret = qcow2_mark_clean(bs); 2752 if (ret < 0) { 2753 goto fail; 2754 } 2755 2756 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2757 if (ret < 0) { 2758 goto fail; 2759 } 2760 2761 return 0; 2762 2763 fail_broken_refcounts: 2764 /* The BDS is unusable at this point. If we wanted to make it usable, we 2765 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2766 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2767 * again. However, because the functions which could have caused this error 2768 * path to be taken are used by those functions as well, it's very likely 2769 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2770 bs->drv = NULL; 2771 2772 fail: 2773 g_free(new_reftable); 2774 return ret; 2775 } 2776 2777 static int qcow2_make_empty(BlockDriverState *bs) 2778 { 2779 BDRVQcow2State *s = bs->opaque; 2780 uint64_t start_sector; 2781 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2782 int l1_clusters, ret = 0; 2783 2784 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2785 2786 if (s->qcow_version >= 3 && !s->snapshots && 2787 3 + l1_clusters <= s->refcount_block_size) { 2788 /* The following function only works for qcow2 v3 images (it requires 2789 * the dirty flag) and only as long as there are no snapshots (because 2790 * it completely empties the image). Furthermore, the L1 table and three 2791 * additional clusters (image header, refcount table, one refcount 2792 * block) have to fit inside one refcount block. */ 2793 return make_completely_empty(bs); 2794 } 2795 2796 /* This fallback code simply discards every active cluster; this is slow, 2797 * but works in all cases */ 2798 for (start_sector = 0; start_sector < bs->total_sectors; 2799 start_sector += sector_step) 2800 { 2801 /* As this function is generally used after committing an external 2802 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2803 * default action for this kind of discard is to pass the discard, 2804 * which will ideally result in an actually smaller image file, as 2805 * is probably desired. */ 2806 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2807 MIN(sector_step, 2808 bs->total_sectors - start_sector), 2809 QCOW2_DISCARD_SNAPSHOT, true); 2810 if (ret < 0) { 2811 break; 2812 } 2813 } 2814 2815 return ret; 2816 } 2817 2818 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2819 { 2820 BDRVQcow2State *s = bs->opaque; 2821 int ret; 2822 2823 qemu_co_mutex_lock(&s->lock); 2824 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2825 if (ret < 0) { 2826 qemu_co_mutex_unlock(&s->lock); 2827 return ret; 2828 } 2829 2830 if (qcow2_need_accurate_refcounts(s)) { 2831 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2832 if (ret < 0) { 2833 qemu_co_mutex_unlock(&s->lock); 2834 return ret; 2835 } 2836 } 2837 qemu_co_mutex_unlock(&s->lock); 2838 2839 return 0; 2840 } 2841 2842 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2843 { 2844 BDRVQcow2State *s = bs->opaque; 2845 bdi->unallocated_blocks_are_zero = true; 2846 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2847 bdi->cluster_size = s->cluster_size; 2848 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2849 return 0; 2850 } 2851 2852 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2853 { 2854 BDRVQcow2State *s = bs->opaque; 2855 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2856 2857 *spec_info = (ImageInfoSpecific){ 2858 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2859 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 2860 }; 2861 if (s->qcow_version == 2) { 2862 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2863 .compat = g_strdup("0.10"), 2864 .refcount_bits = s->refcount_bits, 2865 }; 2866 } else if (s->qcow_version == 3) { 2867 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2868 .compat = g_strdup("1.1"), 2869 .lazy_refcounts = s->compatible_features & 2870 QCOW2_COMPAT_LAZY_REFCOUNTS, 2871 .has_lazy_refcounts = true, 2872 .corrupt = s->incompatible_features & 2873 QCOW2_INCOMPAT_CORRUPT, 2874 .has_corrupt = true, 2875 .refcount_bits = s->refcount_bits, 2876 }; 2877 } else { 2878 /* if this assertion fails, this probably means a new version was 2879 * added without having it covered here */ 2880 assert(false); 2881 } 2882 2883 return spec_info; 2884 } 2885 2886 #if 0 2887 static void dump_refcounts(BlockDriverState *bs) 2888 { 2889 BDRVQcow2State *s = bs->opaque; 2890 int64_t nb_clusters, k, k1, size; 2891 int refcount; 2892 2893 size = bdrv_getlength(bs->file->bs); 2894 nb_clusters = size_to_clusters(s, size); 2895 for(k = 0; k < nb_clusters;) { 2896 k1 = k; 2897 refcount = get_refcount(bs, k); 2898 k++; 2899 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2900 k++; 2901 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2902 k - k1); 2903 } 2904 } 2905 #endif 2906 2907 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2908 int64_t pos) 2909 { 2910 BDRVQcow2State *s = bs->opaque; 2911 int64_t total_sectors = bs->total_sectors; 2912 bool zero_beyond_eof = bs->zero_beyond_eof; 2913 int ret; 2914 2915 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2916 bs->zero_beyond_eof = false; 2917 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2918 bs->zero_beyond_eof = zero_beyond_eof; 2919 2920 /* bdrv_co_do_writev will have increased the total_sectors value to include 2921 * the VM state - the VM state is however not an actual part of the block 2922 * device, therefore, we need to restore the old value. */ 2923 bs->total_sectors = total_sectors; 2924 2925 return ret; 2926 } 2927 2928 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2929 int64_t pos, int size) 2930 { 2931 BDRVQcow2State *s = bs->opaque; 2932 bool zero_beyond_eof = bs->zero_beyond_eof; 2933 int ret; 2934 2935 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2936 bs->zero_beyond_eof = false; 2937 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2938 bs->zero_beyond_eof = zero_beyond_eof; 2939 2940 return ret; 2941 } 2942 2943 /* 2944 * Downgrades an image's version. To achieve this, any incompatible features 2945 * have to be removed. 2946 */ 2947 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2948 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2949 { 2950 BDRVQcow2State *s = bs->opaque; 2951 int current_version = s->qcow_version; 2952 int ret; 2953 2954 if (target_version == current_version) { 2955 return 0; 2956 } else if (target_version > current_version) { 2957 return -EINVAL; 2958 } else if (target_version != 2) { 2959 return -EINVAL; 2960 } 2961 2962 if (s->refcount_order != 4) { 2963 error_report("compat=0.10 requires refcount_bits=16"); 2964 return -ENOTSUP; 2965 } 2966 2967 /* clear incompatible features */ 2968 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2969 ret = qcow2_mark_clean(bs); 2970 if (ret < 0) { 2971 return ret; 2972 } 2973 } 2974 2975 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2976 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2977 * best thing to do anyway */ 2978 2979 if (s->incompatible_features) { 2980 return -ENOTSUP; 2981 } 2982 2983 /* since we can ignore compatible features, we can set them to 0 as well */ 2984 s->compatible_features = 0; 2985 /* if lazy refcounts have been used, they have already been fixed through 2986 * clearing the dirty flag */ 2987 2988 /* clearing autoclear features is trivial */ 2989 s->autoclear_features = 0; 2990 2991 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 2992 if (ret < 0) { 2993 return ret; 2994 } 2995 2996 s->qcow_version = target_version; 2997 ret = qcow2_update_header(bs); 2998 if (ret < 0) { 2999 s->qcow_version = current_version; 3000 return ret; 3001 } 3002 return 0; 3003 } 3004 3005 typedef enum Qcow2AmendOperation { 3006 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 3007 * statically initialized to so that the helper CB can discern the first 3008 * invocation from an operation change */ 3009 QCOW2_NO_OPERATION = 0, 3010 3011 QCOW2_CHANGING_REFCOUNT_ORDER, 3012 QCOW2_DOWNGRADING, 3013 } Qcow2AmendOperation; 3014 3015 typedef struct Qcow2AmendHelperCBInfo { 3016 /* The code coordinating the amend operations should only modify 3017 * these four fields; the rest will be managed by the CB */ 3018 BlockDriverAmendStatusCB *original_status_cb; 3019 void *original_cb_opaque; 3020 3021 Qcow2AmendOperation current_operation; 3022 3023 /* Total number of operations to perform (only set once) */ 3024 int total_operations; 3025 3026 /* The following fields are managed by the CB */ 3027 3028 /* Number of operations completed */ 3029 int operations_completed; 3030 3031 /* Cumulative offset of all completed operations */ 3032 int64_t offset_completed; 3033 3034 Qcow2AmendOperation last_operation; 3035 int64_t last_work_size; 3036 } Qcow2AmendHelperCBInfo; 3037 3038 static void qcow2_amend_helper_cb(BlockDriverState *bs, 3039 int64_t operation_offset, 3040 int64_t operation_work_size, void *opaque) 3041 { 3042 Qcow2AmendHelperCBInfo *info = opaque; 3043 int64_t current_work_size; 3044 int64_t projected_work_size; 3045 3046 if (info->current_operation != info->last_operation) { 3047 if (info->last_operation != QCOW2_NO_OPERATION) { 3048 info->offset_completed += info->last_work_size; 3049 info->operations_completed++; 3050 } 3051 3052 info->last_operation = info->current_operation; 3053 } 3054 3055 assert(info->total_operations > 0); 3056 assert(info->operations_completed < info->total_operations); 3057 3058 info->last_work_size = operation_work_size; 3059 3060 current_work_size = info->offset_completed + operation_work_size; 3061 3062 /* current_work_size is the total work size for (operations_completed + 1) 3063 * operations (which includes this one), so multiply it by the number of 3064 * operations not covered and divide it by the number of operations 3065 * covered to get a projection for the operations not covered */ 3066 projected_work_size = current_work_size * (info->total_operations - 3067 info->operations_completed - 1) 3068 / (info->operations_completed + 1); 3069 3070 info->original_status_cb(bs, info->offset_completed + operation_offset, 3071 current_work_size + projected_work_size, 3072 info->original_cb_opaque); 3073 } 3074 3075 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3076 BlockDriverAmendStatusCB *status_cb, 3077 void *cb_opaque) 3078 { 3079 BDRVQcow2State *s = bs->opaque; 3080 int old_version = s->qcow_version, new_version = old_version; 3081 uint64_t new_size = 0; 3082 const char *backing_file = NULL, *backing_format = NULL; 3083 bool lazy_refcounts = s->use_lazy_refcounts; 3084 const char *compat = NULL; 3085 uint64_t cluster_size = s->cluster_size; 3086 bool encrypt; 3087 int refcount_bits = s->refcount_bits; 3088 int ret; 3089 QemuOptDesc *desc = opts->list->desc; 3090 Qcow2AmendHelperCBInfo helper_cb_info; 3091 3092 while (desc && desc->name) { 3093 if (!qemu_opt_find(opts, desc->name)) { 3094 /* only change explicitly defined options */ 3095 desc++; 3096 continue; 3097 } 3098 3099 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3100 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3101 if (!compat) { 3102 /* preserve default */ 3103 } else if (!strcmp(compat, "0.10")) { 3104 new_version = 2; 3105 } else if (!strcmp(compat, "1.1")) { 3106 new_version = 3; 3107 } else { 3108 error_report("Unknown compatibility level %s", compat); 3109 return -EINVAL; 3110 } 3111 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3112 error_report("Cannot change preallocation mode"); 3113 return -ENOTSUP; 3114 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3115 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3116 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3117 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3118 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3119 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3120 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3121 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3122 !!s->cipher); 3123 3124 if (encrypt != !!s->cipher) { 3125 error_report("Changing the encryption flag is not supported"); 3126 return -ENOTSUP; 3127 } 3128 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3129 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3130 cluster_size); 3131 if (cluster_size != s->cluster_size) { 3132 error_report("Changing the cluster size is not supported"); 3133 return -ENOTSUP; 3134 } 3135 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3136 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3137 lazy_refcounts); 3138 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3139 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3140 refcount_bits); 3141 3142 if (refcount_bits <= 0 || refcount_bits > 64 || 3143 !is_power_of_2(refcount_bits)) 3144 { 3145 error_report("Refcount width must be a power of two and may " 3146 "not exceed 64 bits"); 3147 return -EINVAL; 3148 } 3149 } else { 3150 /* if this point is reached, this probably means a new option was 3151 * added without having it covered here */ 3152 abort(); 3153 } 3154 3155 desc++; 3156 } 3157 3158 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3159 .original_status_cb = status_cb, 3160 .original_cb_opaque = cb_opaque, 3161 .total_operations = (new_version < old_version) 3162 + (s->refcount_bits != refcount_bits) 3163 }; 3164 3165 /* Upgrade first (some features may require compat=1.1) */ 3166 if (new_version > old_version) { 3167 s->qcow_version = new_version; 3168 ret = qcow2_update_header(bs); 3169 if (ret < 0) { 3170 s->qcow_version = old_version; 3171 return ret; 3172 } 3173 } 3174 3175 if (s->refcount_bits != refcount_bits) { 3176 int refcount_order = ctz32(refcount_bits); 3177 Error *local_error = NULL; 3178 3179 if (new_version < 3 && refcount_bits != 16) { 3180 error_report("Different refcount widths than 16 bits require " 3181 "compatibility level 1.1 or above (use compat=1.1 or " 3182 "greater)"); 3183 return -EINVAL; 3184 } 3185 3186 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3187 ret = qcow2_change_refcount_order(bs, refcount_order, 3188 &qcow2_amend_helper_cb, 3189 &helper_cb_info, &local_error); 3190 if (ret < 0) { 3191 error_report_err(local_error); 3192 return ret; 3193 } 3194 } 3195 3196 if (backing_file || backing_format) { 3197 ret = qcow2_change_backing_file(bs, 3198 backing_file ?: s->image_backing_file, 3199 backing_format ?: s->image_backing_format); 3200 if (ret < 0) { 3201 return ret; 3202 } 3203 } 3204 3205 if (s->use_lazy_refcounts != lazy_refcounts) { 3206 if (lazy_refcounts) { 3207 if (new_version < 3) { 3208 error_report("Lazy refcounts only supported with compatibility " 3209 "level 1.1 and above (use compat=1.1 or greater)"); 3210 return -EINVAL; 3211 } 3212 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3213 ret = qcow2_update_header(bs); 3214 if (ret < 0) { 3215 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3216 return ret; 3217 } 3218 s->use_lazy_refcounts = true; 3219 } else { 3220 /* make image clean first */ 3221 ret = qcow2_mark_clean(bs); 3222 if (ret < 0) { 3223 return ret; 3224 } 3225 /* now disallow lazy refcounts */ 3226 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3227 ret = qcow2_update_header(bs); 3228 if (ret < 0) { 3229 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3230 return ret; 3231 } 3232 s->use_lazy_refcounts = false; 3233 } 3234 } 3235 3236 if (new_size) { 3237 ret = bdrv_truncate(bs, new_size); 3238 if (ret < 0) { 3239 return ret; 3240 } 3241 } 3242 3243 /* Downgrade last (so unsupported features can be removed before) */ 3244 if (new_version < old_version) { 3245 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3246 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3247 &helper_cb_info); 3248 if (ret < 0) { 3249 return ret; 3250 } 3251 } 3252 3253 return 0; 3254 } 3255 3256 /* 3257 * If offset or size are negative, respectively, they will not be included in 3258 * the BLOCK_IMAGE_CORRUPTED event emitted. 3259 * fatal will be ignored for read-only BDS; corruptions found there will always 3260 * be considered non-fatal. 3261 */ 3262 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3263 int64_t size, const char *message_format, ...) 3264 { 3265 BDRVQcow2State *s = bs->opaque; 3266 const char *node_name; 3267 char *message; 3268 va_list ap; 3269 3270 fatal = fatal && !bs->read_only; 3271 3272 if (s->signaled_corruption && 3273 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3274 { 3275 return; 3276 } 3277 3278 va_start(ap, message_format); 3279 message = g_strdup_vprintf(message_format, ap); 3280 va_end(ap); 3281 3282 if (fatal) { 3283 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3284 "corruption events will be suppressed\n", message); 3285 } else { 3286 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3287 "corruption events will be suppressed\n", message); 3288 } 3289 3290 node_name = bdrv_get_node_name(bs); 3291 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3292 *node_name != '\0', node_name, 3293 message, offset >= 0, offset, 3294 size >= 0, size, 3295 fatal, &error_abort); 3296 g_free(message); 3297 3298 if (fatal) { 3299 qcow2_mark_corrupt(bs); 3300 bs->drv = NULL; /* make BDS unusable */ 3301 } 3302 3303 s->signaled_corruption = true; 3304 } 3305 3306 static QemuOptsList qcow2_create_opts = { 3307 .name = "qcow2-create-opts", 3308 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3309 .desc = { 3310 { 3311 .name = BLOCK_OPT_SIZE, 3312 .type = QEMU_OPT_SIZE, 3313 .help = "Virtual disk size" 3314 }, 3315 { 3316 .name = BLOCK_OPT_COMPAT_LEVEL, 3317 .type = QEMU_OPT_STRING, 3318 .help = "Compatibility level (0.10 or 1.1)" 3319 }, 3320 { 3321 .name = BLOCK_OPT_BACKING_FILE, 3322 .type = QEMU_OPT_STRING, 3323 .help = "File name of a base image" 3324 }, 3325 { 3326 .name = BLOCK_OPT_BACKING_FMT, 3327 .type = QEMU_OPT_STRING, 3328 .help = "Image format of the base image" 3329 }, 3330 { 3331 .name = BLOCK_OPT_ENCRYPT, 3332 .type = QEMU_OPT_BOOL, 3333 .help = "Encrypt the image", 3334 .def_value_str = "off" 3335 }, 3336 { 3337 .name = BLOCK_OPT_CLUSTER_SIZE, 3338 .type = QEMU_OPT_SIZE, 3339 .help = "qcow2 cluster size", 3340 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3341 }, 3342 { 3343 .name = BLOCK_OPT_PREALLOC, 3344 .type = QEMU_OPT_STRING, 3345 .help = "Preallocation mode (allowed values: off, metadata, " 3346 "falloc, full)" 3347 }, 3348 { 3349 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3350 .type = QEMU_OPT_BOOL, 3351 .help = "Postpone refcount updates", 3352 .def_value_str = "off" 3353 }, 3354 { 3355 .name = BLOCK_OPT_REFCOUNT_BITS, 3356 .type = QEMU_OPT_NUMBER, 3357 .help = "Width of a reference count entry in bits", 3358 .def_value_str = "16" 3359 }, 3360 { /* end of list */ } 3361 } 3362 }; 3363 3364 BlockDriver bdrv_qcow2 = { 3365 .format_name = "qcow2", 3366 .instance_size = sizeof(BDRVQcow2State), 3367 .bdrv_probe = qcow2_probe, 3368 .bdrv_open = qcow2_open, 3369 .bdrv_close = qcow2_close, 3370 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3371 .bdrv_reopen_commit = qcow2_reopen_commit, 3372 .bdrv_reopen_abort = qcow2_reopen_abort, 3373 .bdrv_join_options = qcow2_join_options, 3374 .bdrv_create = qcow2_create, 3375 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3376 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3377 .bdrv_set_key = qcow2_set_key, 3378 3379 .bdrv_co_readv = qcow2_co_readv, 3380 .bdrv_co_writev = qcow2_co_writev, 3381 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3382 3383 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3384 .bdrv_co_discard = qcow2_co_discard, 3385 .bdrv_truncate = qcow2_truncate, 3386 .bdrv_write_compressed = qcow2_write_compressed, 3387 .bdrv_make_empty = qcow2_make_empty, 3388 3389 .bdrv_snapshot_create = qcow2_snapshot_create, 3390 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3391 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3392 .bdrv_snapshot_list = qcow2_snapshot_list, 3393 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3394 .bdrv_get_info = qcow2_get_info, 3395 .bdrv_get_specific_info = qcow2_get_specific_info, 3396 3397 .bdrv_save_vmstate = qcow2_save_vmstate, 3398 .bdrv_load_vmstate = qcow2_load_vmstate, 3399 3400 .supports_backing = true, 3401 .bdrv_change_backing_file = qcow2_change_backing_file, 3402 3403 .bdrv_refresh_limits = qcow2_refresh_limits, 3404 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3405 .bdrv_inactivate = qcow2_inactivate, 3406 3407 .create_opts = &qcow2_create_opts, 3408 .bdrv_check = qcow2_check, 3409 .bdrv_amend_options = qcow2_amend_options, 3410 3411 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3412 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3413 }; 3414 3415 static void bdrv_qcow2_init(void) 3416 { 3417 bdrv_register(&bdrv_qcow2); 3418 } 3419 3420 block_init(bdrv_qcow2_init); 3421