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, 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, 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, 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, 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, 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 #ifndef CONFIG_LINUX 672 if (r->cache_clean_interval != 0) { 673 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 674 " not supported on this host"); 675 ret = -EINVAL; 676 goto fail; 677 } 678 #endif 679 if (r->cache_clean_interval > UINT_MAX) { 680 error_setg(errp, "Cache clean interval too big"); 681 ret = -EINVAL; 682 goto fail; 683 } 684 685 /* lazy-refcounts; flush if going from enabled to disabled */ 686 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 687 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 688 if (r->use_lazy_refcounts && s->qcow_version < 3) { 689 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 690 "qemu 1.1 compatibility level"); 691 ret = -EINVAL; 692 goto fail; 693 } 694 695 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 696 ret = qcow2_mark_clean(bs); 697 if (ret < 0) { 698 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 699 goto fail; 700 } 701 } 702 703 /* Overlap check options */ 704 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 705 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 706 if (opt_overlap_check_template && opt_overlap_check && 707 strcmp(opt_overlap_check_template, opt_overlap_check)) 708 { 709 error_setg(errp, "Conflicting values for qcow2 options '" 710 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 711 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 712 ret = -EINVAL; 713 goto fail; 714 } 715 if (!opt_overlap_check) { 716 opt_overlap_check = opt_overlap_check_template ?: "cached"; 717 } 718 719 if (!strcmp(opt_overlap_check, "none")) { 720 overlap_check_template = 0; 721 } else if (!strcmp(opt_overlap_check, "constant")) { 722 overlap_check_template = QCOW2_OL_CONSTANT; 723 } else if (!strcmp(opt_overlap_check, "cached")) { 724 overlap_check_template = QCOW2_OL_CACHED; 725 } else if (!strcmp(opt_overlap_check, "all")) { 726 overlap_check_template = QCOW2_OL_ALL; 727 } else { 728 error_setg(errp, "Unsupported value '%s' for qcow2 option " 729 "'overlap-check'. Allowed are any of the following: " 730 "none, constant, cached, all", opt_overlap_check); 731 ret = -EINVAL; 732 goto fail; 733 } 734 735 r->overlap_check = 0; 736 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 737 /* overlap-check defines a template bitmask, but every flag may be 738 * overwritten through the associated boolean option */ 739 r->overlap_check |= 740 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 741 overlap_check_template & (1 << i)) << i; 742 } 743 744 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 745 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 746 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 747 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 748 flags & BDRV_O_UNMAP); 749 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 750 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 751 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 752 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 753 754 ret = 0; 755 fail: 756 qemu_opts_del(opts); 757 opts = NULL; 758 return ret; 759 } 760 761 static void qcow2_update_options_commit(BlockDriverState *bs, 762 Qcow2ReopenState *r) 763 { 764 BDRVQcow2State *s = bs->opaque; 765 int i; 766 767 if (s->l2_table_cache) { 768 qcow2_cache_destroy(bs, s->l2_table_cache); 769 } 770 if (s->refcount_block_cache) { 771 qcow2_cache_destroy(bs, s->refcount_block_cache); 772 } 773 s->l2_table_cache = r->l2_table_cache; 774 s->refcount_block_cache = r->refcount_block_cache; 775 776 s->overlap_check = r->overlap_check; 777 s->use_lazy_refcounts = r->use_lazy_refcounts; 778 779 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 780 s->discard_passthrough[i] = r->discard_passthrough[i]; 781 } 782 783 if (s->cache_clean_interval != r->cache_clean_interval) { 784 cache_clean_timer_del(bs); 785 s->cache_clean_interval = r->cache_clean_interval; 786 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 787 } 788 } 789 790 static void qcow2_update_options_abort(BlockDriverState *bs, 791 Qcow2ReopenState *r) 792 { 793 if (r->l2_table_cache) { 794 qcow2_cache_destroy(bs, r->l2_table_cache); 795 } 796 if (r->refcount_block_cache) { 797 qcow2_cache_destroy(bs, r->refcount_block_cache); 798 } 799 } 800 801 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 802 int flags, Error **errp) 803 { 804 Qcow2ReopenState r = {}; 805 int ret; 806 807 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 808 if (ret >= 0) { 809 qcow2_update_options_commit(bs, &r); 810 } else { 811 qcow2_update_options_abort(bs, &r); 812 } 813 814 return ret; 815 } 816 817 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 818 Error **errp) 819 { 820 BDRVQcow2State *s = bs->opaque; 821 unsigned int len, i; 822 int ret = 0; 823 QCowHeader header; 824 Error *local_err = NULL; 825 uint64_t ext_end; 826 uint64_t l1_vm_state_index; 827 828 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 829 if (ret < 0) { 830 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 831 goto fail; 832 } 833 be32_to_cpus(&header.magic); 834 be32_to_cpus(&header.version); 835 be64_to_cpus(&header.backing_file_offset); 836 be32_to_cpus(&header.backing_file_size); 837 be64_to_cpus(&header.size); 838 be32_to_cpus(&header.cluster_bits); 839 be32_to_cpus(&header.crypt_method); 840 be64_to_cpus(&header.l1_table_offset); 841 be32_to_cpus(&header.l1_size); 842 be64_to_cpus(&header.refcount_table_offset); 843 be32_to_cpus(&header.refcount_table_clusters); 844 be64_to_cpus(&header.snapshots_offset); 845 be32_to_cpus(&header.nb_snapshots); 846 847 if (header.magic != QCOW_MAGIC) { 848 error_setg(errp, "Image is not in qcow2 format"); 849 ret = -EINVAL; 850 goto fail; 851 } 852 if (header.version < 2 || header.version > 3) { 853 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 854 ret = -ENOTSUP; 855 goto fail; 856 } 857 858 s->qcow_version = header.version; 859 860 /* Initialise cluster size */ 861 if (header.cluster_bits < MIN_CLUSTER_BITS || 862 header.cluster_bits > MAX_CLUSTER_BITS) { 863 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 864 header.cluster_bits); 865 ret = -EINVAL; 866 goto fail; 867 } 868 869 s->cluster_bits = header.cluster_bits; 870 s->cluster_size = 1 << s->cluster_bits; 871 s->cluster_sectors = 1 << (s->cluster_bits - 9); 872 873 /* Initialise version 3 header fields */ 874 if (header.version == 2) { 875 header.incompatible_features = 0; 876 header.compatible_features = 0; 877 header.autoclear_features = 0; 878 header.refcount_order = 4; 879 header.header_length = 72; 880 } else { 881 be64_to_cpus(&header.incompatible_features); 882 be64_to_cpus(&header.compatible_features); 883 be64_to_cpus(&header.autoclear_features); 884 be32_to_cpus(&header.refcount_order); 885 be32_to_cpus(&header.header_length); 886 887 if (header.header_length < 104) { 888 error_setg(errp, "qcow2 header too short"); 889 ret = -EINVAL; 890 goto fail; 891 } 892 } 893 894 if (header.header_length > s->cluster_size) { 895 error_setg(errp, "qcow2 header exceeds cluster size"); 896 ret = -EINVAL; 897 goto fail; 898 } 899 900 if (header.header_length > sizeof(header)) { 901 s->unknown_header_fields_size = header.header_length - sizeof(header); 902 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 903 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 904 s->unknown_header_fields_size); 905 if (ret < 0) { 906 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 907 "fields"); 908 goto fail; 909 } 910 } 911 912 if (header.backing_file_offset > s->cluster_size) { 913 error_setg(errp, "Invalid backing file offset"); 914 ret = -EINVAL; 915 goto fail; 916 } 917 918 if (header.backing_file_offset) { 919 ext_end = header.backing_file_offset; 920 } else { 921 ext_end = 1 << header.cluster_bits; 922 } 923 924 /* Handle feature bits */ 925 s->incompatible_features = header.incompatible_features; 926 s->compatible_features = header.compatible_features; 927 s->autoclear_features = header.autoclear_features; 928 929 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 930 void *feature_table = NULL; 931 qcow2_read_extensions(bs, header.header_length, ext_end, 932 &feature_table, NULL); 933 report_unsupported_feature(errp, feature_table, 934 s->incompatible_features & 935 ~QCOW2_INCOMPAT_MASK); 936 ret = -ENOTSUP; 937 g_free(feature_table); 938 goto fail; 939 } 940 941 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 942 /* Corrupt images may not be written to unless they are being repaired 943 */ 944 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 945 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 946 "read/write"); 947 ret = -EACCES; 948 goto fail; 949 } 950 } 951 952 /* Check support for various header values */ 953 if (header.refcount_order > 6) { 954 error_setg(errp, "Reference count entry width too large; may not " 955 "exceed 64 bits"); 956 ret = -EINVAL; 957 goto fail; 958 } 959 s->refcount_order = header.refcount_order; 960 s->refcount_bits = 1 << s->refcount_order; 961 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 962 s->refcount_max += s->refcount_max - 1; 963 964 if (header.crypt_method > QCOW_CRYPT_AES) { 965 error_setg(errp, "Unsupported encryption method: %" PRIu32, 966 header.crypt_method); 967 ret = -EINVAL; 968 goto fail; 969 } 970 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128, 971 QCRYPTO_CIPHER_MODE_CBC)) { 972 error_setg(errp, "AES cipher not available"); 973 ret = -EINVAL; 974 goto fail; 975 } 976 s->crypt_method_header = header.crypt_method; 977 if (s->crypt_method_header) { 978 if (bdrv_uses_whitelist() && 979 s->crypt_method_header == QCOW_CRYPT_AES) { 980 error_setg(errp, 981 "Use of AES-CBC encrypted qcow2 images is no longer " 982 "supported in system emulators"); 983 error_append_hint(errp, 984 "You can use 'qemu-img convert' to convert your " 985 "image to an alternative supported format, such " 986 "as unencrypted qcow2, or raw with the LUKS " 987 "format instead.\n"); 988 ret = -ENOSYS; 989 goto fail; 990 } 991 992 bs->encrypted = true; 993 } 994 995 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 996 s->l2_size = 1 << s->l2_bits; 997 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 998 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 999 s->refcount_block_size = 1 << s->refcount_block_bits; 1000 bs->total_sectors = header.size / 512; 1001 s->csize_shift = (62 - (s->cluster_bits - 8)); 1002 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1003 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1004 1005 s->refcount_table_offset = header.refcount_table_offset; 1006 s->refcount_table_size = 1007 header.refcount_table_clusters << (s->cluster_bits - 3); 1008 1009 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 1010 error_setg(errp, "Reference count table too large"); 1011 ret = -EINVAL; 1012 goto fail; 1013 } 1014 1015 ret = validate_table_offset(bs, s->refcount_table_offset, 1016 s->refcount_table_size, sizeof(uint64_t)); 1017 if (ret < 0) { 1018 error_setg(errp, "Invalid reference count table offset"); 1019 goto fail; 1020 } 1021 1022 /* Snapshot table offset/length */ 1023 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1024 error_setg(errp, "Too many snapshots"); 1025 ret = -EINVAL; 1026 goto fail; 1027 } 1028 1029 ret = validate_table_offset(bs, header.snapshots_offset, 1030 header.nb_snapshots, 1031 sizeof(QCowSnapshotHeader)); 1032 if (ret < 0) { 1033 error_setg(errp, "Invalid snapshot table offset"); 1034 goto fail; 1035 } 1036 1037 /* read the level 1 table */ 1038 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1039 error_setg(errp, "Active L1 table too large"); 1040 ret = -EFBIG; 1041 goto fail; 1042 } 1043 s->l1_size = header.l1_size; 1044 1045 l1_vm_state_index = size_to_l1(s, header.size); 1046 if (l1_vm_state_index > INT_MAX) { 1047 error_setg(errp, "Image is too big"); 1048 ret = -EFBIG; 1049 goto fail; 1050 } 1051 s->l1_vm_state_index = l1_vm_state_index; 1052 1053 /* the L1 table must contain at least enough entries to put 1054 header.size bytes */ 1055 if (s->l1_size < s->l1_vm_state_index) { 1056 error_setg(errp, "L1 table is too small"); 1057 ret = -EINVAL; 1058 goto fail; 1059 } 1060 1061 ret = validate_table_offset(bs, header.l1_table_offset, 1062 header.l1_size, sizeof(uint64_t)); 1063 if (ret < 0) { 1064 error_setg(errp, "Invalid L1 table offset"); 1065 goto fail; 1066 } 1067 s->l1_table_offset = header.l1_table_offset; 1068 1069 1070 if (s->l1_size > 0) { 1071 s->l1_table = qemu_try_blockalign(bs->file->bs, 1072 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1073 if (s->l1_table == NULL) { 1074 error_setg(errp, "Could not allocate L1 table"); 1075 ret = -ENOMEM; 1076 goto fail; 1077 } 1078 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1079 s->l1_size * sizeof(uint64_t)); 1080 if (ret < 0) { 1081 error_setg_errno(errp, -ret, "Could not read L1 table"); 1082 goto fail; 1083 } 1084 for(i = 0;i < s->l1_size; i++) { 1085 be64_to_cpus(&s->l1_table[i]); 1086 } 1087 } 1088 1089 /* Parse driver-specific options */ 1090 ret = qcow2_update_options(bs, options, flags, errp); 1091 if (ret < 0) { 1092 goto fail; 1093 } 1094 1095 s->cluster_cache = g_malloc(s->cluster_size); 1096 /* one more sector for decompressed data alignment */ 1097 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1098 * s->cluster_size + 512); 1099 if (s->cluster_data == NULL) { 1100 error_setg(errp, "Could not allocate temporary cluster buffer"); 1101 ret = -ENOMEM; 1102 goto fail; 1103 } 1104 1105 s->cluster_cache_offset = -1; 1106 s->flags = flags; 1107 1108 ret = qcow2_refcount_init(bs); 1109 if (ret != 0) { 1110 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1111 goto fail; 1112 } 1113 1114 QLIST_INIT(&s->cluster_allocs); 1115 QTAILQ_INIT(&s->discards); 1116 1117 /* read qcow2 extensions */ 1118 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1119 &local_err)) { 1120 error_propagate(errp, local_err); 1121 ret = -EINVAL; 1122 goto fail; 1123 } 1124 1125 /* read the backing file name */ 1126 if (header.backing_file_offset != 0) { 1127 len = header.backing_file_size; 1128 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1129 len >= sizeof(bs->backing_file)) { 1130 error_setg(errp, "Backing file name too long"); 1131 ret = -EINVAL; 1132 goto fail; 1133 } 1134 ret = bdrv_pread(bs->file, header.backing_file_offset, 1135 bs->backing_file, len); 1136 if (ret < 0) { 1137 error_setg_errno(errp, -ret, "Could not read backing file name"); 1138 goto fail; 1139 } 1140 bs->backing_file[len] = '\0'; 1141 s->image_backing_file = g_strdup(bs->backing_file); 1142 } 1143 1144 /* Internal snapshots */ 1145 s->snapshots_offset = header.snapshots_offset; 1146 s->nb_snapshots = header.nb_snapshots; 1147 1148 ret = qcow2_read_snapshots(bs); 1149 if (ret < 0) { 1150 error_setg_errno(errp, -ret, "Could not read snapshots"); 1151 goto fail; 1152 } 1153 1154 /* Clear unknown autoclear feature bits */ 1155 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { 1156 s->autoclear_features = 0; 1157 ret = qcow2_update_header(bs); 1158 if (ret < 0) { 1159 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1160 goto fail; 1161 } 1162 } 1163 1164 /* Initialise locks */ 1165 qemu_co_mutex_init(&s->lock); 1166 bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP; 1167 1168 /* Repair image if dirty */ 1169 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1170 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1171 BdrvCheckResult result = {0}; 1172 1173 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1174 if (ret < 0) { 1175 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1176 goto fail; 1177 } 1178 } 1179 1180 #ifdef DEBUG_ALLOC 1181 { 1182 BdrvCheckResult result = {0}; 1183 qcow2_check_refcounts(bs, &result, 0); 1184 } 1185 #endif 1186 return ret; 1187 1188 fail: 1189 g_free(s->unknown_header_fields); 1190 cleanup_unknown_header_ext(bs); 1191 qcow2_free_snapshots(bs); 1192 qcow2_refcount_close(bs); 1193 qemu_vfree(s->l1_table); 1194 /* else pre-write overlap checks in cache_destroy may crash */ 1195 s->l1_table = NULL; 1196 cache_clean_timer_del(bs); 1197 if (s->l2_table_cache) { 1198 qcow2_cache_destroy(bs, s->l2_table_cache); 1199 } 1200 if (s->refcount_block_cache) { 1201 qcow2_cache_destroy(bs, s->refcount_block_cache); 1202 } 1203 g_free(s->cluster_cache); 1204 qemu_vfree(s->cluster_data); 1205 return ret; 1206 } 1207 1208 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1209 { 1210 BDRVQcow2State *s = bs->opaque; 1211 1212 if (bs->encrypted) { 1213 /* Encryption works on a sector granularity */ 1214 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 1215 } 1216 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1217 bs->bl.pdiscard_alignment = s->cluster_size; 1218 } 1219 1220 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1221 { 1222 BDRVQcow2State *s = bs->opaque; 1223 uint8_t keybuf[16]; 1224 int len, i; 1225 Error *err = NULL; 1226 1227 memset(keybuf, 0, 16); 1228 len = strlen(key); 1229 if (len > 16) 1230 len = 16; 1231 /* XXX: we could compress the chars to 7 bits to increase 1232 entropy */ 1233 for(i = 0;i < len;i++) { 1234 keybuf[i] = key[i]; 1235 } 1236 assert(bs->encrypted); 1237 1238 qcrypto_cipher_free(s->cipher); 1239 s->cipher = qcrypto_cipher_new( 1240 QCRYPTO_CIPHER_ALG_AES_128, 1241 QCRYPTO_CIPHER_MODE_CBC, 1242 keybuf, G_N_ELEMENTS(keybuf), 1243 &err); 1244 1245 if (!s->cipher) { 1246 /* XXX would be nice if errors in this method could 1247 * be properly propagate to the caller. Would need 1248 * the bdrv_set_key() API signature to be fixed. */ 1249 error_free(err); 1250 return -1; 1251 } 1252 return 0; 1253 } 1254 1255 static int qcow2_reopen_prepare(BDRVReopenState *state, 1256 BlockReopenQueue *queue, Error **errp) 1257 { 1258 Qcow2ReopenState *r; 1259 int ret; 1260 1261 r = g_new0(Qcow2ReopenState, 1); 1262 state->opaque = r; 1263 1264 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1265 state->flags, errp); 1266 if (ret < 0) { 1267 goto fail; 1268 } 1269 1270 /* We need to write out any unwritten data if we reopen read-only. */ 1271 if ((state->flags & BDRV_O_RDWR) == 0) { 1272 ret = bdrv_flush(state->bs); 1273 if (ret < 0) { 1274 goto fail; 1275 } 1276 1277 ret = qcow2_mark_clean(state->bs); 1278 if (ret < 0) { 1279 goto fail; 1280 } 1281 } 1282 1283 return 0; 1284 1285 fail: 1286 qcow2_update_options_abort(state->bs, r); 1287 g_free(r); 1288 return ret; 1289 } 1290 1291 static void qcow2_reopen_commit(BDRVReopenState *state) 1292 { 1293 qcow2_update_options_commit(state->bs, state->opaque); 1294 g_free(state->opaque); 1295 } 1296 1297 static void qcow2_reopen_abort(BDRVReopenState *state) 1298 { 1299 qcow2_update_options_abort(state->bs, state->opaque); 1300 g_free(state->opaque); 1301 } 1302 1303 static void qcow2_join_options(QDict *options, QDict *old_options) 1304 { 1305 bool has_new_overlap_template = 1306 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1307 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1308 bool has_new_total_cache_size = 1309 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1310 bool has_all_cache_options; 1311 1312 /* New overlap template overrides all old overlap options */ 1313 if (has_new_overlap_template) { 1314 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1315 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1316 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1317 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1318 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1319 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1320 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1321 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1322 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1323 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1324 } 1325 1326 /* New total cache size overrides all old options */ 1327 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1328 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1329 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1330 } 1331 1332 qdict_join(options, old_options, false); 1333 1334 /* 1335 * If after merging all cache size options are set, an old total size is 1336 * overwritten. Do keep all options, however, if all three are new. The 1337 * resulting error message is what we want to happen. 1338 */ 1339 has_all_cache_options = 1340 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1341 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1342 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1343 1344 if (has_all_cache_options && !has_new_total_cache_size) { 1345 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1346 } 1347 } 1348 1349 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1350 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1351 { 1352 BDRVQcow2State *s = bs->opaque; 1353 uint64_t cluster_offset; 1354 int index_in_cluster, ret; 1355 unsigned int bytes; 1356 int64_t status = 0; 1357 1358 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE); 1359 qemu_co_mutex_lock(&s->lock); 1360 ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes, 1361 &cluster_offset); 1362 qemu_co_mutex_unlock(&s->lock); 1363 if (ret < 0) { 1364 return ret; 1365 } 1366 1367 *pnum = bytes >> BDRV_SECTOR_BITS; 1368 1369 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1370 !s->cipher) { 1371 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1372 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1373 *file = bs->file->bs; 1374 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1375 } 1376 if (ret == QCOW2_CLUSTER_ZERO) { 1377 status |= BDRV_BLOCK_ZERO; 1378 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1379 status |= BDRV_BLOCK_DATA; 1380 } 1381 return status; 1382 } 1383 1384 /* handle reading after the end of the backing file */ 1385 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1386 int64_t offset, int bytes) 1387 { 1388 uint64_t bs_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1389 int n1; 1390 1391 if ((offset + bytes) <= bs_size) { 1392 return bytes; 1393 } 1394 1395 if (offset >= bs_size) { 1396 n1 = 0; 1397 } else { 1398 n1 = bs_size - offset; 1399 } 1400 1401 qemu_iovec_memset(qiov, n1, 0, bytes - n1); 1402 1403 return n1; 1404 } 1405 1406 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1407 uint64_t bytes, QEMUIOVector *qiov, 1408 int flags) 1409 { 1410 BDRVQcow2State *s = bs->opaque; 1411 int offset_in_cluster, n1; 1412 int ret; 1413 unsigned int cur_bytes; /* number of bytes in current iteration */ 1414 uint64_t cluster_offset = 0; 1415 uint64_t bytes_done = 0; 1416 QEMUIOVector hd_qiov; 1417 uint8_t *cluster_data = NULL; 1418 1419 qemu_iovec_init(&hd_qiov, qiov->niov); 1420 1421 qemu_co_mutex_lock(&s->lock); 1422 1423 while (bytes != 0) { 1424 1425 /* prepare next request */ 1426 cur_bytes = MIN(bytes, INT_MAX); 1427 if (s->cipher) { 1428 cur_bytes = MIN(cur_bytes, 1429 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1430 } 1431 1432 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1433 if (ret < 0) { 1434 goto fail; 1435 } 1436 1437 offset_in_cluster = offset_into_cluster(s, offset); 1438 1439 qemu_iovec_reset(&hd_qiov); 1440 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1441 1442 switch (ret) { 1443 case QCOW2_CLUSTER_UNALLOCATED: 1444 1445 if (bs->backing) { 1446 /* read from the base image */ 1447 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1448 offset, cur_bytes); 1449 if (n1 > 0) { 1450 QEMUIOVector local_qiov; 1451 1452 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1453 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1); 1454 1455 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1456 qemu_co_mutex_unlock(&s->lock); 1457 ret = bdrv_co_preadv(bs->backing, offset, n1, 1458 &local_qiov, 0); 1459 qemu_co_mutex_lock(&s->lock); 1460 1461 qemu_iovec_destroy(&local_qiov); 1462 1463 if (ret < 0) { 1464 goto fail; 1465 } 1466 } 1467 } else { 1468 /* Note: in this case, no need to wait */ 1469 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1470 } 1471 break; 1472 1473 case QCOW2_CLUSTER_ZERO: 1474 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1475 break; 1476 1477 case QCOW2_CLUSTER_COMPRESSED: 1478 /* add AIO support for compressed blocks ? */ 1479 ret = qcow2_decompress_cluster(bs, cluster_offset); 1480 if (ret < 0) { 1481 goto fail; 1482 } 1483 1484 qemu_iovec_from_buf(&hd_qiov, 0, 1485 s->cluster_cache + offset_in_cluster, 1486 cur_bytes); 1487 break; 1488 1489 case QCOW2_CLUSTER_NORMAL: 1490 if ((cluster_offset & 511) != 0) { 1491 ret = -EIO; 1492 goto fail; 1493 } 1494 1495 if (bs->encrypted) { 1496 assert(s->cipher); 1497 1498 /* 1499 * For encrypted images, read everything into a temporary 1500 * contiguous buffer on which the AES functions can work. 1501 */ 1502 if (!cluster_data) { 1503 cluster_data = 1504 qemu_try_blockalign(bs->file->bs, 1505 QCOW_MAX_CRYPT_CLUSTERS 1506 * s->cluster_size); 1507 if (cluster_data == NULL) { 1508 ret = -ENOMEM; 1509 goto fail; 1510 } 1511 } 1512 1513 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1514 qemu_iovec_reset(&hd_qiov); 1515 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1516 } 1517 1518 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1519 qemu_co_mutex_unlock(&s->lock); 1520 ret = bdrv_co_preadv(bs->file, 1521 cluster_offset + offset_in_cluster, 1522 cur_bytes, &hd_qiov, 0); 1523 qemu_co_mutex_lock(&s->lock); 1524 if (ret < 0) { 1525 goto fail; 1526 } 1527 if (bs->encrypted) { 1528 assert(s->cipher); 1529 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1530 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1531 Error *err = NULL; 1532 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS, 1533 cluster_data, cluster_data, 1534 cur_bytes >> BDRV_SECTOR_BITS, 1535 false, &err) < 0) { 1536 error_free(err); 1537 ret = -EIO; 1538 goto fail; 1539 } 1540 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1541 } 1542 break; 1543 1544 default: 1545 g_assert_not_reached(); 1546 ret = -EIO; 1547 goto fail; 1548 } 1549 1550 bytes -= cur_bytes; 1551 offset += cur_bytes; 1552 bytes_done += cur_bytes; 1553 } 1554 ret = 0; 1555 1556 fail: 1557 qemu_co_mutex_unlock(&s->lock); 1558 1559 qemu_iovec_destroy(&hd_qiov); 1560 qemu_vfree(cluster_data); 1561 1562 return ret; 1563 } 1564 1565 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 1566 uint64_t bytes, QEMUIOVector *qiov, 1567 int flags) 1568 { 1569 BDRVQcow2State *s = bs->opaque; 1570 int offset_in_cluster; 1571 int ret; 1572 unsigned int cur_bytes; /* number of sectors in current iteration */ 1573 uint64_t cluster_offset; 1574 QEMUIOVector hd_qiov; 1575 uint64_t bytes_done = 0; 1576 uint8_t *cluster_data = NULL; 1577 QCowL2Meta *l2meta = NULL; 1578 1579 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 1580 1581 qemu_iovec_init(&hd_qiov, qiov->niov); 1582 1583 s->cluster_cache_offset = -1; /* disable compressed cache */ 1584 1585 qemu_co_mutex_lock(&s->lock); 1586 1587 while (bytes != 0) { 1588 1589 l2meta = NULL; 1590 1591 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1592 offset_in_cluster = offset_into_cluster(s, offset); 1593 cur_bytes = MIN(bytes, INT_MAX); 1594 if (bs->encrypted) { 1595 cur_bytes = MIN(cur_bytes, 1596 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 1597 - offset_in_cluster); 1598 } 1599 1600 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 1601 &cluster_offset, &l2meta); 1602 if (ret < 0) { 1603 goto fail; 1604 } 1605 1606 assert((cluster_offset & 511) == 0); 1607 1608 qemu_iovec_reset(&hd_qiov); 1609 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1610 1611 if (bs->encrypted) { 1612 Error *err = NULL; 1613 assert(s->cipher); 1614 if (!cluster_data) { 1615 cluster_data = qemu_try_blockalign(bs->file->bs, 1616 QCOW_MAX_CRYPT_CLUSTERS 1617 * s->cluster_size); 1618 if (cluster_data == NULL) { 1619 ret = -ENOMEM; 1620 goto fail; 1621 } 1622 } 1623 1624 assert(hd_qiov.size <= 1625 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1626 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1627 1628 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS, 1629 cluster_data, cluster_data, 1630 cur_bytes >>BDRV_SECTOR_BITS, 1631 true, &err) < 0) { 1632 error_free(err); 1633 ret = -EIO; 1634 goto fail; 1635 } 1636 1637 qemu_iovec_reset(&hd_qiov); 1638 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1639 } 1640 1641 ret = qcow2_pre_write_overlap_check(bs, 0, 1642 cluster_offset + offset_in_cluster, cur_bytes); 1643 if (ret < 0) { 1644 goto fail; 1645 } 1646 1647 qemu_co_mutex_unlock(&s->lock); 1648 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1649 trace_qcow2_writev_data(qemu_coroutine_self(), 1650 cluster_offset + offset_in_cluster); 1651 ret = bdrv_co_pwritev(bs->file, 1652 cluster_offset + offset_in_cluster, 1653 cur_bytes, &hd_qiov, 0); 1654 qemu_co_mutex_lock(&s->lock); 1655 if (ret < 0) { 1656 goto fail; 1657 } 1658 1659 while (l2meta != NULL) { 1660 QCowL2Meta *next; 1661 1662 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1663 if (ret < 0) { 1664 goto fail; 1665 } 1666 1667 /* Take the request off the list of running requests */ 1668 if (l2meta->nb_clusters != 0) { 1669 QLIST_REMOVE(l2meta, next_in_flight); 1670 } 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 bytes -= cur_bytes; 1680 offset += cur_bytes; 1681 bytes_done += cur_bytes; 1682 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 1683 } 1684 ret = 0; 1685 1686 fail: 1687 qemu_co_mutex_unlock(&s->lock); 1688 1689 while (l2meta != NULL) { 1690 QCowL2Meta *next; 1691 1692 if (l2meta->nb_clusters != 0) { 1693 QLIST_REMOVE(l2meta, next_in_flight); 1694 } 1695 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1696 1697 next = l2meta->next; 1698 g_free(l2meta); 1699 l2meta = next; 1700 } 1701 1702 qemu_iovec_destroy(&hd_qiov); 1703 qemu_vfree(cluster_data); 1704 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1705 1706 return ret; 1707 } 1708 1709 static int qcow2_inactivate(BlockDriverState *bs) 1710 { 1711 BDRVQcow2State *s = bs->opaque; 1712 int ret, result = 0; 1713 1714 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1715 if (ret) { 1716 result = ret; 1717 error_report("Failed to flush the L2 table cache: %s", 1718 strerror(-ret)); 1719 } 1720 1721 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1722 if (ret) { 1723 result = ret; 1724 error_report("Failed to flush the refcount block cache: %s", 1725 strerror(-ret)); 1726 } 1727 1728 if (result == 0) { 1729 qcow2_mark_clean(bs); 1730 } 1731 1732 return result; 1733 } 1734 1735 static void qcow2_close(BlockDriverState *bs) 1736 { 1737 BDRVQcow2State *s = bs->opaque; 1738 qemu_vfree(s->l1_table); 1739 /* else pre-write overlap checks in cache_destroy may crash */ 1740 s->l1_table = NULL; 1741 1742 if (!(s->flags & BDRV_O_INACTIVE)) { 1743 qcow2_inactivate(bs); 1744 } 1745 1746 cache_clean_timer_del(bs); 1747 qcow2_cache_destroy(bs, s->l2_table_cache); 1748 qcow2_cache_destroy(bs, s->refcount_block_cache); 1749 1750 qcrypto_cipher_free(s->cipher); 1751 s->cipher = NULL; 1752 1753 g_free(s->unknown_header_fields); 1754 cleanup_unknown_header_ext(bs); 1755 1756 g_free(s->image_backing_file); 1757 g_free(s->image_backing_format); 1758 1759 g_free(s->cluster_cache); 1760 qemu_vfree(s->cluster_data); 1761 qcow2_refcount_close(bs); 1762 qcow2_free_snapshots(bs); 1763 } 1764 1765 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1766 { 1767 BDRVQcow2State *s = bs->opaque; 1768 int flags = s->flags; 1769 QCryptoCipher *cipher = NULL; 1770 QDict *options; 1771 Error *local_err = NULL; 1772 int ret; 1773 1774 /* 1775 * Backing files are read-only which makes all of their metadata immutable, 1776 * that means we don't have to worry about reopening them here. 1777 */ 1778 1779 cipher = s->cipher; 1780 s->cipher = NULL; 1781 1782 qcow2_close(bs); 1783 1784 memset(s, 0, sizeof(BDRVQcow2State)); 1785 options = qdict_clone_shallow(bs->options); 1786 1787 flags &= ~BDRV_O_INACTIVE; 1788 ret = qcow2_open(bs, options, flags, &local_err); 1789 QDECREF(options); 1790 if (local_err) { 1791 error_propagate(errp, local_err); 1792 error_prepend(errp, "Could not reopen qcow2 layer: "); 1793 bs->drv = NULL; 1794 return; 1795 } else if (ret < 0) { 1796 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1797 bs->drv = NULL; 1798 return; 1799 } 1800 1801 s->cipher = cipher; 1802 } 1803 1804 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1805 size_t len, size_t buflen) 1806 { 1807 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1808 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1809 1810 if (buflen < ext_len) { 1811 return -ENOSPC; 1812 } 1813 1814 *ext_backing_fmt = (QCowExtension) { 1815 .magic = cpu_to_be32(magic), 1816 .len = cpu_to_be32(len), 1817 }; 1818 1819 if (len) { 1820 memcpy(buf + sizeof(QCowExtension), s, len); 1821 } 1822 1823 return ext_len; 1824 } 1825 1826 /* 1827 * Updates the qcow2 header, including the variable length parts of it, i.e. 1828 * the backing file name and all extensions. qcow2 was not designed to allow 1829 * such changes, so if we run out of space (we can only use the first cluster) 1830 * this function may fail. 1831 * 1832 * Returns 0 on success, -errno in error cases. 1833 */ 1834 int qcow2_update_header(BlockDriverState *bs) 1835 { 1836 BDRVQcow2State *s = bs->opaque; 1837 QCowHeader *header; 1838 char *buf; 1839 size_t buflen = s->cluster_size; 1840 int ret; 1841 uint64_t total_size; 1842 uint32_t refcount_table_clusters; 1843 size_t header_length; 1844 Qcow2UnknownHeaderExtension *uext; 1845 1846 buf = qemu_blockalign(bs, buflen); 1847 1848 /* Header structure */ 1849 header = (QCowHeader*) buf; 1850 1851 if (buflen < sizeof(*header)) { 1852 ret = -ENOSPC; 1853 goto fail; 1854 } 1855 1856 header_length = sizeof(*header) + s->unknown_header_fields_size; 1857 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1858 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1859 1860 *header = (QCowHeader) { 1861 /* Version 2 fields */ 1862 .magic = cpu_to_be32(QCOW_MAGIC), 1863 .version = cpu_to_be32(s->qcow_version), 1864 .backing_file_offset = 0, 1865 .backing_file_size = 0, 1866 .cluster_bits = cpu_to_be32(s->cluster_bits), 1867 .size = cpu_to_be64(total_size), 1868 .crypt_method = cpu_to_be32(s->crypt_method_header), 1869 .l1_size = cpu_to_be32(s->l1_size), 1870 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1871 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1872 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1873 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1874 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1875 1876 /* Version 3 fields */ 1877 .incompatible_features = cpu_to_be64(s->incompatible_features), 1878 .compatible_features = cpu_to_be64(s->compatible_features), 1879 .autoclear_features = cpu_to_be64(s->autoclear_features), 1880 .refcount_order = cpu_to_be32(s->refcount_order), 1881 .header_length = cpu_to_be32(header_length), 1882 }; 1883 1884 /* For older versions, write a shorter header */ 1885 switch (s->qcow_version) { 1886 case 2: 1887 ret = offsetof(QCowHeader, incompatible_features); 1888 break; 1889 case 3: 1890 ret = sizeof(*header); 1891 break; 1892 default: 1893 ret = -EINVAL; 1894 goto fail; 1895 } 1896 1897 buf += ret; 1898 buflen -= ret; 1899 memset(buf, 0, buflen); 1900 1901 /* Preserve any unknown field in the header */ 1902 if (s->unknown_header_fields_size) { 1903 if (buflen < s->unknown_header_fields_size) { 1904 ret = -ENOSPC; 1905 goto fail; 1906 } 1907 1908 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1909 buf += s->unknown_header_fields_size; 1910 buflen -= s->unknown_header_fields_size; 1911 } 1912 1913 /* Backing file format header extension */ 1914 if (s->image_backing_format) { 1915 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1916 s->image_backing_format, 1917 strlen(s->image_backing_format), 1918 buflen); 1919 if (ret < 0) { 1920 goto fail; 1921 } 1922 1923 buf += ret; 1924 buflen -= ret; 1925 } 1926 1927 /* Feature table */ 1928 if (s->qcow_version >= 3) { 1929 Qcow2Feature features[] = { 1930 { 1931 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1932 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1933 .name = "dirty bit", 1934 }, 1935 { 1936 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1937 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1938 .name = "corrupt bit", 1939 }, 1940 { 1941 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1942 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1943 .name = "lazy refcounts", 1944 }, 1945 }; 1946 1947 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1948 features, sizeof(features), buflen); 1949 if (ret < 0) { 1950 goto fail; 1951 } 1952 buf += ret; 1953 buflen -= ret; 1954 } 1955 1956 /* Keep unknown header extensions */ 1957 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1958 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1959 if (ret < 0) { 1960 goto fail; 1961 } 1962 1963 buf += ret; 1964 buflen -= ret; 1965 } 1966 1967 /* End of header extensions */ 1968 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1969 if (ret < 0) { 1970 goto fail; 1971 } 1972 1973 buf += ret; 1974 buflen -= ret; 1975 1976 /* Backing file name */ 1977 if (s->image_backing_file) { 1978 size_t backing_file_len = strlen(s->image_backing_file); 1979 1980 if (buflen < backing_file_len) { 1981 ret = -ENOSPC; 1982 goto fail; 1983 } 1984 1985 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1986 strncpy(buf, s->image_backing_file, buflen); 1987 1988 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1989 header->backing_file_size = cpu_to_be32(backing_file_len); 1990 } 1991 1992 /* Write the new header */ 1993 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 1994 if (ret < 0) { 1995 goto fail; 1996 } 1997 1998 ret = 0; 1999 fail: 2000 qemu_vfree(header); 2001 return ret; 2002 } 2003 2004 static int qcow2_change_backing_file(BlockDriverState *bs, 2005 const char *backing_file, const char *backing_fmt) 2006 { 2007 BDRVQcow2State *s = bs->opaque; 2008 2009 if (backing_file && strlen(backing_file) > 1023) { 2010 return -EINVAL; 2011 } 2012 2013 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2014 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2015 2016 g_free(s->image_backing_file); 2017 g_free(s->image_backing_format); 2018 2019 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2020 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2021 2022 return qcow2_update_header(bs); 2023 } 2024 2025 static int preallocate(BlockDriverState *bs) 2026 { 2027 uint64_t bytes; 2028 uint64_t offset; 2029 uint64_t host_offset = 0; 2030 unsigned int cur_bytes; 2031 int ret; 2032 QCowL2Meta *meta; 2033 2034 bytes = bdrv_getlength(bs); 2035 offset = 0; 2036 2037 while (bytes) { 2038 cur_bytes = MIN(bytes, INT_MAX); 2039 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2040 &host_offset, &meta); 2041 if (ret < 0) { 2042 return ret; 2043 } 2044 2045 while (meta) { 2046 QCowL2Meta *next = meta->next; 2047 2048 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2049 if (ret < 0) { 2050 qcow2_free_any_clusters(bs, meta->alloc_offset, 2051 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2052 return ret; 2053 } 2054 2055 /* There are no dependent requests, but we need to remove our 2056 * request from the list of in-flight requests */ 2057 QLIST_REMOVE(meta, next_in_flight); 2058 2059 g_free(meta); 2060 meta = next; 2061 } 2062 2063 /* TODO Preallocate data if requested */ 2064 2065 bytes -= cur_bytes; 2066 offset += cur_bytes; 2067 } 2068 2069 /* 2070 * It is expected that the image file is large enough to actually contain 2071 * all of the allocated clusters (otherwise we get failing reads after 2072 * EOF). Extend the image to the last allocated sector. 2073 */ 2074 if (host_offset != 0) { 2075 uint8_t data = 0; 2076 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2077 &data, 1); 2078 if (ret < 0) { 2079 return ret; 2080 } 2081 } 2082 2083 return 0; 2084 } 2085 2086 static int qcow2_create2(const char *filename, int64_t total_size, 2087 const char *backing_file, const char *backing_format, 2088 int flags, size_t cluster_size, PreallocMode prealloc, 2089 QemuOpts *opts, int version, int refcount_order, 2090 Error **errp) 2091 { 2092 int cluster_bits; 2093 QDict *options; 2094 2095 /* Calculate cluster_bits */ 2096 cluster_bits = ctz32(cluster_size); 2097 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2098 (1 << cluster_bits) != cluster_size) 2099 { 2100 error_setg(errp, "Cluster size must be a power of two between %d and " 2101 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2102 return -EINVAL; 2103 } 2104 2105 /* 2106 * Open the image file and write a minimal qcow2 header. 2107 * 2108 * We keep things simple and start with a zero-sized image. We also 2109 * do without refcount blocks or a L1 table for now. We'll fix the 2110 * inconsistency later. 2111 * 2112 * We do need a refcount table because growing the refcount table means 2113 * allocating two new refcount blocks - the seconds of which would be at 2114 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2115 * size for any qcow2 image. 2116 */ 2117 BlockBackend *blk; 2118 QCowHeader *header; 2119 uint64_t* refcount_table; 2120 Error *local_err = NULL; 2121 int ret; 2122 2123 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2124 /* Note: The following calculation does not need to be exact; if it is a 2125 * bit off, either some bytes will be "leaked" (which is fine) or we 2126 * will need to increase the file size by some bytes (which is fine, 2127 * too, as long as the bulk is allocated here). Therefore, using 2128 * floating point arithmetic is fine. */ 2129 int64_t meta_size = 0; 2130 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2131 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2132 int refblock_bits, refblock_size; 2133 /* refcount entry size in bytes */ 2134 double rces = (1 << refcount_order) / 8.; 2135 2136 /* see qcow2_open() */ 2137 refblock_bits = cluster_bits - (refcount_order - 3); 2138 refblock_size = 1 << refblock_bits; 2139 2140 /* header: 1 cluster */ 2141 meta_size += cluster_size; 2142 2143 /* total size of L2 tables */ 2144 nl2e = aligned_total_size / cluster_size; 2145 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2146 meta_size += nl2e * sizeof(uint64_t); 2147 2148 /* total size of L1 tables */ 2149 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2150 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2151 meta_size += nl1e * sizeof(uint64_t); 2152 2153 /* total size of refcount blocks 2154 * 2155 * note: every host cluster is reference-counted, including metadata 2156 * (even refcount blocks are recursively included). 2157 * Let: 2158 * a = total_size (this is the guest disk size) 2159 * m = meta size not including refcount blocks and refcount tables 2160 * c = cluster size 2161 * y1 = number of refcount blocks entries 2162 * y2 = meta size including everything 2163 * rces = refcount entry size in bytes 2164 * then, 2165 * y1 = (y2 + a)/c 2166 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2167 * we can get y1: 2168 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2169 */ 2170 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2171 / (cluster_size - rces - rces * sizeof(uint64_t) 2172 / cluster_size); 2173 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2174 2175 /* total size of refcount tables */ 2176 nreftablee = nrefblocke / refblock_size; 2177 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2178 meta_size += nreftablee * sizeof(uint64_t); 2179 2180 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2181 aligned_total_size + meta_size, &error_abort); 2182 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2183 &error_abort); 2184 } 2185 2186 ret = bdrv_create_file(filename, opts, &local_err); 2187 if (ret < 0) { 2188 error_propagate(errp, local_err); 2189 return ret; 2190 } 2191 2192 blk = blk_new_open(filename, NULL, NULL, 2193 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); 2194 if (blk == NULL) { 2195 error_propagate(errp, local_err); 2196 return -EIO; 2197 } 2198 2199 blk_set_allow_write_beyond_eof(blk, true); 2200 2201 /* Write the header */ 2202 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2203 header = g_malloc0(cluster_size); 2204 *header = (QCowHeader) { 2205 .magic = cpu_to_be32(QCOW_MAGIC), 2206 .version = cpu_to_be32(version), 2207 .cluster_bits = cpu_to_be32(cluster_bits), 2208 .size = cpu_to_be64(0), 2209 .l1_table_offset = cpu_to_be64(0), 2210 .l1_size = cpu_to_be32(0), 2211 .refcount_table_offset = cpu_to_be64(cluster_size), 2212 .refcount_table_clusters = cpu_to_be32(1), 2213 .refcount_order = cpu_to_be32(refcount_order), 2214 .header_length = cpu_to_be32(sizeof(*header)), 2215 }; 2216 2217 if (flags & BLOCK_FLAG_ENCRYPT) { 2218 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2219 } else { 2220 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2221 } 2222 2223 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2224 header->compatible_features |= 2225 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2226 } 2227 2228 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2229 g_free(header); 2230 if (ret < 0) { 2231 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2232 goto out; 2233 } 2234 2235 /* Write a refcount table with one refcount block */ 2236 refcount_table = g_malloc0(2 * cluster_size); 2237 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2238 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2239 g_free(refcount_table); 2240 2241 if (ret < 0) { 2242 error_setg_errno(errp, -ret, "Could not write refcount table"); 2243 goto out; 2244 } 2245 2246 blk_unref(blk); 2247 blk = NULL; 2248 2249 /* 2250 * And now open the image and make it consistent first (i.e. increase the 2251 * refcount of the cluster that is occupied by the header and the refcount 2252 * table) 2253 */ 2254 options = qdict_new(); 2255 qdict_put(options, "driver", qstring_from_str("qcow2")); 2256 blk = blk_new_open(filename, NULL, options, 2257 BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err); 2258 if (blk == NULL) { 2259 error_propagate(errp, local_err); 2260 ret = -EIO; 2261 goto out; 2262 } 2263 2264 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2265 if (ret < 0) { 2266 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2267 "header and refcount table"); 2268 goto out; 2269 2270 } else if (ret != 0) { 2271 error_report("Huh, first cluster in empty image is already in use?"); 2272 abort(); 2273 } 2274 2275 /* Create a full header (including things like feature table) */ 2276 ret = qcow2_update_header(blk_bs(blk)); 2277 if (ret < 0) { 2278 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2279 goto out; 2280 } 2281 2282 /* Okay, now that we have a valid image, let's give it the right size */ 2283 ret = blk_truncate(blk, total_size); 2284 if (ret < 0) { 2285 error_setg_errno(errp, -ret, "Could not resize image"); 2286 goto out; 2287 } 2288 2289 /* Want a backing file? There you go.*/ 2290 if (backing_file) { 2291 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2292 if (ret < 0) { 2293 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2294 "with format '%s'", backing_file, backing_format); 2295 goto out; 2296 } 2297 } 2298 2299 /* And if we're supposed to preallocate metadata, do that now */ 2300 if (prealloc != PREALLOC_MODE_OFF) { 2301 BDRVQcow2State *s = blk_bs(blk)->opaque; 2302 qemu_co_mutex_lock(&s->lock); 2303 ret = preallocate(blk_bs(blk)); 2304 qemu_co_mutex_unlock(&s->lock); 2305 if (ret < 0) { 2306 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2307 goto out; 2308 } 2309 } 2310 2311 blk_unref(blk); 2312 blk = NULL; 2313 2314 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2315 options = qdict_new(); 2316 qdict_put(options, "driver", qstring_from_str("qcow2")); 2317 blk = blk_new_open(filename, NULL, options, 2318 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err); 2319 if (blk == NULL) { 2320 error_propagate(errp, local_err); 2321 ret = -EIO; 2322 goto out; 2323 } 2324 2325 ret = 0; 2326 out: 2327 if (blk) { 2328 blk_unref(blk); 2329 } 2330 return ret; 2331 } 2332 2333 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2334 { 2335 char *backing_file = NULL; 2336 char *backing_fmt = NULL; 2337 char *buf = NULL; 2338 uint64_t size = 0; 2339 int flags = 0; 2340 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2341 PreallocMode prealloc; 2342 int version = 3; 2343 uint64_t refcount_bits = 16; 2344 int refcount_order; 2345 Error *local_err = NULL; 2346 int ret; 2347 2348 /* Read out options */ 2349 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2350 BDRV_SECTOR_SIZE); 2351 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2352 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2353 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2354 flags |= BLOCK_FLAG_ENCRYPT; 2355 } 2356 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2357 DEFAULT_CLUSTER_SIZE); 2358 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2359 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2360 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2361 &local_err); 2362 if (local_err) { 2363 error_propagate(errp, local_err); 2364 ret = -EINVAL; 2365 goto finish; 2366 } 2367 g_free(buf); 2368 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2369 if (!buf) { 2370 /* keep the default */ 2371 } else if (!strcmp(buf, "0.10")) { 2372 version = 2; 2373 } else if (!strcmp(buf, "1.1")) { 2374 version = 3; 2375 } else { 2376 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2377 ret = -EINVAL; 2378 goto finish; 2379 } 2380 2381 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2382 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2383 } 2384 2385 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2386 error_setg(errp, "Backing file and preallocation cannot be used at " 2387 "the same time"); 2388 ret = -EINVAL; 2389 goto finish; 2390 } 2391 2392 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2393 error_setg(errp, "Lazy refcounts only supported with compatibility " 2394 "level 1.1 and above (use compat=1.1 or greater)"); 2395 ret = -EINVAL; 2396 goto finish; 2397 } 2398 2399 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2400 refcount_bits); 2401 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2402 error_setg(errp, "Refcount width must be a power of two and may not " 2403 "exceed 64 bits"); 2404 ret = -EINVAL; 2405 goto finish; 2406 } 2407 2408 if (version < 3 && refcount_bits != 16) { 2409 error_setg(errp, "Different refcount widths than 16 bits require " 2410 "compatibility level 1.1 or above (use compat=1.1 or " 2411 "greater)"); 2412 ret = -EINVAL; 2413 goto finish; 2414 } 2415 2416 refcount_order = ctz32(refcount_bits); 2417 2418 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2419 cluster_size, prealloc, opts, version, refcount_order, 2420 &local_err); 2421 error_propagate(errp, local_err); 2422 2423 finish: 2424 g_free(backing_file); 2425 g_free(backing_fmt); 2426 g_free(buf); 2427 return ret; 2428 } 2429 2430 2431 static bool is_zero_sectors(BlockDriverState *bs, int64_t start, 2432 uint32_t count) 2433 { 2434 int nr; 2435 BlockDriverState *file; 2436 int64_t res; 2437 2438 if (!count) { 2439 return true; 2440 } 2441 res = bdrv_get_block_status_above(bs, NULL, start, count, 2442 &nr, &file); 2443 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count; 2444 } 2445 2446 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 2447 int64_t offset, int count, BdrvRequestFlags flags) 2448 { 2449 int ret; 2450 BDRVQcow2State *s = bs->opaque; 2451 2452 uint32_t head = offset % s->cluster_size; 2453 uint32_t tail = (offset + count) % s->cluster_size; 2454 2455 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, count); 2456 2457 if (head || tail) { 2458 int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS; 2459 uint64_t off; 2460 unsigned int nr; 2461 2462 assert(head + count <= s->cluster_size); 2463 2464 /* check whether remainder of cluster already reads as zero */ 2465 if (!(is_zero_sectors(bs, cl_start, 2466 DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) && 2467 is_zero_sectors(bs, (offset + count) >> BDRV_SECTOR_BITS, 2468 DIV_ROUND_UP(-tail & (s->cluster_size - 1), 2469 BDRV_SECTOR_SIZE)))) { 2470 return -ENOTSUP; 2471 } 2472 2473 qemu_co_mutex_lock(&s->lock); 2474 /* We can have new write after previous check */ 2475 offset = cl_start << BDRV_SECTOR_BITS; 2476 count = s->cluster_size; 2477 nr = s->cluster_size; 2478 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 2479 if (ret != QCOW2_CLUSTER_UNALLOCATED && ret != QCOW2_CLUSTER_ZERO) { 2480 qemu_co_mutex_unlock(&s->lock); 2481 return -ENOTSUP; 2482 } 2483 } else { 2484 qemu_co_mutex_lock(&s->lock); 2485 } 2486 2487 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, count); 2488 2489 /* Whatever is left can use real zero clusters */ 2490 ret = qcow2_zero_clusters(bs, offset, count >> BDRV_SECTOR_BITS, flags); 2491 qemu_co_mutex_unlock(&s->lock); 2492 2493 return ret; 2494 } 2495 2496 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 2497 int64_t offset, int count) 2498 { 2499 int ret; 2500 BDRVQcow2State *s = bs->opaque; 2501 2502 if (!QEMU_IS_ALIGNED(offset | count, s->cluster_size)) { 2503 assert(count < s->cluster_size); 2504 return -ENOTSUP; 2505 } 2506 2507 qemu_co_mutex_lock(&s->lock); 2508 ret = qcow2_discard_clusters(bs, offset, count >> BDRV_SECTOR_BITS, 2509 QCOW2_DISCARD_REQUEST, false); 2510 qemu_co_mutex_unlock(&s->lock); 2511 return ret; 2512 } 2513 2514 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2515 { 2516 BDRVQcow2State *s = bs->opaque; 2517 int64_t new_l1_size; 2518 int ret; 2519 2520 if (offset & 511) { 2521 error_report("The new size must be a multiple of 512"); 2522 return -EINVAL; 2523 } 2524 2525 /* cannot proceed if image has snapshots */ 2526 if (s->nb_snapshots) { 2527 error_report("Can't resize an image which has snapshots"); 2528 return -ENOTSUP; 2529 } 2530 2531 /* shrinking is currently not supported */ 2532 if (offset < bs->total_sectors * 512) { 2533 error_report("qcow2 doesn't support shrinking images yet"); 2534 return -ENOTSUP; 2535 } 2536 2537 new_l1_size = size_to_l1(s, offset); 2538 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2539 if (ret < 0) { 2540 return ret; 2541 } 2542 2543 /* write updated header.size */ 2544 offset = cpu_to_be64(offset); 2545 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 2546 &offset, sizeof(uint64_t)); 2547 if (ret < 0) { 2548 return ret; 2549 } 2550 2551 s->l1_vm_state_index = new_l1_size; 2552 return 0; 2553 } 2554 2555 /* XXX: put compressed sectors first, then all the cluster aligned 2556 tables to avoid losing bytes in alignment */ 2557 static coroutine_fn int 2558 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 2559 uint64_t bytes, QEMUIOVector *qiov) 2560 { 2561 BDRVQcow2State *s = bs->opaque; 2562 QEMUIOVector hd_qiov; 2563 struct iovec iov; 2564 z_stream strm; 2565 int ret, out_len; 2566 uint8_t *buf, *out_buf; 2567 uint64_t cluster_offset; 2568 2569 if (bytes == 0) { 2570 /* align end of file to a sector boundary to ease reading with 2571 sector based I/Os */ 2572 cluster_offset = bdrv_getlength(bs->file->bs); 2573 return bdrv_truncate(bs->file->bs, cluster_offset); 2574 } 2575 2576 buf = qemu_blockalign(bs, s->cluster_size); 2577 if (bytes != s->cluster_size) { 2578 if (bytes > s->cluster_size || 2579 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 2580 { 2581 qemu_vfree(buf); 2582 return -EINVAL; 2583 } 2584 /* Zero-pad last write if image size is not cluster aligned */ 2585 memset(buf + bytes, 0, s->cluster_size - bytes); 2586 } 2587 qemu_iovec_to_buf(qiov, 0, buf, bytes); 2588 2589 out_buf = g_malloc(s->cluster_size); 2590 2591 /* best compression, small window, no zlib header */ 2592 memset(&strm, 0, sizeof(strm)); 2593 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2594 Z_DEFLATED, -12, 2595 9, Z_DEFAULT_STRATEGY); 2596 if (ret != 0) { 2597 ret = -EINVAL; 2598 goto fail; 2599 } 2600 2601 strm.avail_in = s->cluster_size; 2602 strm.next_in = (uint8_t *)buf; 2603 strm.avail_out = s->cluster_size; 2604 strm.next_out = out_buf; 2605 2606 ret = deflate(&strm, Z_FINISH); 2607 if (ret != Z_STREAM_END && ret != Z_OK) { 2608 deflateEnd(&strm); 2609 ret = -EINVAL; 2610 goto fail; 2611 } 2612 out_len = strm.next_out - out_buf; 2613 2614 deflateEnd(&strm); 2615 2616 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2617 /* could not compress: write normal cluster */ 2618 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 2619 if (ret < 0) { 2620 goto fail; 2621 } 2622 goto success; 2623 } 2624 2625 qemu_co_mutex_lock(&s->lock); 2626 cluster_offset = 2627 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); 2628 if (!cluster_offset) { 2629 qemu_co_mutex_unlock(&s->lock); 2630 ret = -EIO; 2631 goto fail; 2632 } 2633 cluster_offset &= s->cluster_offset_mask; 2634 2635 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2636 qemu_co_mutex_unlock(&s->lock); 2637 if (ret < 0) { 2638 goto fail; 2639 } 2640 2641 iov = (struct iovec) { 2642 .iov_base = out_buf, 2643 .iov_len = out_len, 2644 }; 2645 qemu_iovec_init_external(&hd_qiov, &iov, 1); 2646 2647 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2648 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 2649 if (ret < 0) { 2650 goto fail; 2651 } 2652 success: 2653 ret = 0; 2654 fail: 2655 qemu_vfree(buf); 2656 g_free(out_buf); 2657 return ret; 2658 } 2659 2660 static int make_completely_empty(BlockDriverState *bs) 2661 { 2662 BDRVQcow2State *s = bs->opaque; 2663 int ret, l1_clusters; 2664 int64_t offset; 2665 uint64_t *new_reftable = NULL; 2666 uint64_t rt_entry, l1_size2; 2667 struct { 2668 uint64_t l1_offset; 2669 uint64_t reftable_offset; 2670 uint32_t reftable_clusters; 2671 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2672 2673 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2674 if (ret < 0) { 2675 goto fail; 2676 } 2677 2678 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2679 if (ret < 0) { 2680 goto fail; 2681 } 2682 2683 /* Refcounts will be broken utterly */ 2684 ret = qcow2_mark_dirty(bs); 2685 if (ret < 0) { 2686 goto fail; 2687 } 2688 2689 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2690 2691 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2692 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2693 2694 /* After this call, neither the in-memory nor the on-disk refcount 2695 * information accurately describe the actual references */ 2696 2697 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 2698 l1_clusters * s->cluster_size, 0); 2699 if (ret < 0) { 2700 goto fail_broken_refcounts; 2701 } 2702 memset(s->l1_table, 0, l1_size2); 2703 2704 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2705 2706 /* Overwrite enough clusters at the beginning of the sectors to place 2707 * the refcount table, a refcount block and the L1 table in; this may 2708 * overwrite parts of the existing refcount and L1 table, which is not 2709 * an issue because the dirty flag is set, complete data loss is in fact 2710 * desired and partial data loss is consequently fine as well */ 2711 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 2712 (2 + l1_clusters) * s->cluster_size, 0); 2713 /* This call (even if it failed overall) may have overwritten on-disk 2714 * refcount structures; in that case, the in-memory refcount information 2715 * will probably differ from the on-disk information which makes the BDS 2716 * unusable */ 2717 if (ret < 0) { 2718 goto fail_broken_refcounts; 2719 } 2720 2721 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2722 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2723 2724 /* "Create" an empty reftable (one cluster) directly after the image 2725 * header and an empty L1 table three clusters after the image header; 2726 * the cluster between those two will be used as the first refblock */ 2727 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 2728 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 2729 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 2730 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 2731 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2732 if (ret < 0) { 2733 goto fail_broken_refcounts; 2734 } 2735 2736 s->l1_table_offset = 3 * s->cluster_size; 2737 2738 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2739 if (!new_reftable) { 2740 ret = -ENOMEM; 2741 goto fail_broken_refcounts; 2742 } 2743 2744 s->refcount_table_offset = s->cluster_size; 2745 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2746 s->max_refcount_table_index = 0; 2747 2748 g_free(s->refcount_table); 2749 s->refcount_table = new_reftable; 2750 new_reftable = NULL; 2751 2752 /* Now the in-memory refcount information again corresponds to the on-disk 2753 * information (reftable is empty and no refblocks (the refblock cache is 2754 * empty)); however, this means some clusters (e.g. the image header) are 2755 * referenced, but not refcounted, but the normal qcow2 code assumes that 2756 * the in-memory information is always correct */ 2757 2758 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2759 2760 /* Enter the first refblock into the reftable */ 2761 rt_entry = cpu_to_be64(2 * s->cluster_size); 2762 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 2763 &rt_entry, sizeof(rt_entry)); 2764 if (ret < 0) { 2765 goto fail_broken_refcounts; 2766 } 2767 s->refcount_table[0] = 2 * s->cluster_size; 2768 2769 s->free_cluster_index = 0; 2770 assert(3 + l1_clusters <= s->refcount_block_size); 2771 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2772 if (offset < 0) { 2773 ret = offset; 2774 goto fail_broken_refcounts; 2775 } else if (offset > 0) { 2776 error_report("First cluster in emptied image is in use"); 2777 abort(); 2778 } 2779 2780 /* Now finally the in-memory information corresponds to the on-disk 2781 * structures and is correct */ 2782 ret = qcow2_mark_clean(bs); 2783 if (ret < 0) { 2784 goto fail; 2785 } 2786 2787 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2788 if (ret < 0) { 2789 goto fail; 2790 } 2791 2792 return 0; 2793 2794 fail_broken_refcounts: 2795 /* The BDS is unusable at this point. If we wanted to make it usable, we 2796 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2797 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2798 * again. However, because the functions which could have caused this error 2799 * path to be taken are used by those functions as well, it's very likely 2800 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2801 bs->drv = NULL; 2802 2803 fail: 2804 g_free(new_reftable); 2805 return ret; 2806 } 2807 2808 static int qcow2_make_empty(BlockDriverState *bs) 2809 { 2810 BDRVQcow2State *s = bs->opaque; 2811 uint64_t start_sector; 2812 int sector_step = (QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size) / 2813 BDRV_SECTOR_SIZE); 2814 int l1_clusters, ret = 0; 2815 2816 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2817 2818 if (s->qcow_version >= 3 && !s->snapshots && 2819 3 + l1_clusters <= s->refcount_block_size) { 2820 /* The following function only works for qcow2 v3 images (it requires 2821 * the dirty flag) and only as long as there are no snapshots (because 2822 * it completely empties the image). Furthermore, the L1 table and three 2823 * additional clusters (image header, refcount table, one refcount 2824 * block) have to fit inside one refcount block. */ 2825 return make_completely_empty(bs); 2826 } 2827 2828 /* This fallback code simply discards every active cluster; this is slow, 2829 * but works in all cases */ 2830 for (start_sector = 0; start_sector < bs->total_sectors; 2831 start_sector += sector_step) 2832 { 2833 /* As this function is generally used after committing an external 2834 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2835 * default action for this kind of discard is to pass the discard, 2836 * which will ideally result in an actually smaller image file, as 2837 * is probably desired. */ 2838 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2839 MIN(sector_step, 2840 bs->total_sectors - start_sector), 2841 QCOW2_DISCARD_SNAPSHOT, true); 2842 if (ret < 0) { 2843 break; 2844 } 2845 } 2846 2847 return ret; 2848 } 2849 2850 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2851 { 2852 BDRVQcow2State *s = bs->opaque; 2853 int ret; 2854 2855 qemu_co_mutex_lock(&s->lock); 2856 ret = qcow2_cache_write(bs, s->l2_table_cache); 2857 if (ret < 0) { 2858 qemu_co_mutex_unlock(&s->lock); 2859 return ret; 2860 } 2861 2862 if (qcow2_need_accurate_refcounts(s)) { 2863 ret = qcow2_cache_write(bs, s->refcount_block_cache); 2864 if (ret < 0) { 2865 qemu_co_mutex_unlock(&s->lock); 2866 return ret; 2867 } 2868 } 2869 qemu_co_mutex_unlock(&s->lock); 2870 2871 return 0; 2872 } 2873 2874 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2875 { 2876 BDRVQcow2State *s = bs->opaque; 2877 bdi->unallocated_blocks_are_zero = true; 2878 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2879 bdi->cluster_size = s->cluster_size; 2880 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2881 return 0; 2882 } 2883 2884 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2885 { 2886 BDRVQcow2State *s = bs->opaque; 2887 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2888 2889 *spec_info = (ImageInfoSpecific){ 2890 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2891 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 2892 }; 2893 if (s->qcow_version == 2) { 2894 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2895 .compat = g_strdup("0.10"), 2896 .refcount_bits = s->refcount_bits, 2897 }; 2898 } else if (s->qcow_version == 3) { 2899 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2900 .compat = g_strdup("1.1"), 2901 .lazy_refcounts = s->compatible_features & 2902 QCOW2_COMPAT_LAZY_REFCOUNTS, 2903 .has_lazy_refcounts = true, 2904 .corrupt = s->incompatible_features & 2905 QCOW2_INCOMPAT_CORRUPT, 2906 .has_corrupt = true, 2907 .refcount_bits = s->refcount_bits, 2908 }; 2909 } else { 2910 /* if this assertion fails, this probably means a new version was 2911 * added without having it covered here */ 2912 assert(false); 2913 } 2914 2915 return spec_info; 2916 } 2917 2918 #if 0 2919 static void dump_refcounts(BlockDriverState *bs) 2920 { 2921 BDRVQcow2State *s = bs->opaque; 2922 int64_t nb_clusters, k, k1, size; 2923 int refcount; 2924 2925 size = bdrv_getlength(bs->file->bs); 2926 nb_clusters = size_to_clusters(s, size); 2927 for(k = 0; k < nb_clusters;) { 2928 k1 = k; 2929 refcount = get_refcount(bs, k); 2930 k++; 2931 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2932 k++; 2933 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2934 k - k1); 2935 } 2936 } 2937 #endif 2938 2939 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2940 int64_t pos) 2941 { 2942 BDRVQcow2State *s = bs->opaque; 2943 2944 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2945 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 2946 qiov->size, qiov, 0); 2947 } 2948 2949 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2950 int64_t pos) 2951 { 2952 BDRVQcow2State *s = bs->opaque; 2953 2954 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2955 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 2956 qiov->size, qiov, 0); 2957 } 2958 2959 /* 2960 * Downgrades an image's version. To achieve this, any incompatible features 2961 * have to be removed. 2962 */ 2963 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2964 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2965 { 2966 BDRVQcow2State *s = bs->opaque; 2967 int current_version = s->qcow_version; 2968 int ret; 2969 2970 if (target_version == current_version) { 2971 return 0; 2972 } else if (target_version > current_version) { 2973 return -EINVAL; 2974 } else if (target_version != 2) { 2975 return -EINVAL; 2976 } 2977 2978 if (s->refcount_order != 4) { 2979 error_report("compat=0.10 requires refcount_bits=16"); 2980 return -ENOTSUP; 2981 } 2982 2983 /* clear incompatible features */ 2984 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2985 ret = qcow2_mark_clean(bs); 2986 if (ret < 0) { 2987 return ret; 2988 } 2989 } 2990 2991 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2992 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2993 * best thing to do anyway */ 2994 2995 if (s->incompatible_features) { 2996 return -ENOTSUP; 2997 } 2998 2999 /* since we can ignore compatible features, we can set them to 0 as well */ 3000 s->compatible_features = 0; 3001 /* if lazy refcounts have been used, they have already been fixed through 3002 * clearing the dirty flag */ 3003 3004 /* clearing autoclear features is trivial */ 3005 s->autoclear_features = 0; 3006 3007 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 3008 if (ret < 0) { 3009 return ret; 3010 } 3011 3012 s->qcow_version = target_version; 3013 ret = qcow2_update_header(bs); 3014 if (ret < 0) { 3015 s->qcow_version = current_version; 3016 return ret; 3017 } 3018 return 0; 3019 } 3020 3021 typedef enum Qcow2AmendOperation { 3022 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 3023 * statically initialized to so that the helper CB can discern the first 3024 * invocation from an operation change */ 3025 QCOW2_NO_OPERATION = 0, 3026 3027 QCOW2_CHANGING_REFCOUNT_ORDER, 3028 QCOW2_DOWNGRADING, 3029 } Qcow2AmendOperation; 3030 3031 typedef struct Qcow2AmendHelperCBInfo { 3032 /* The code coordinating the amend operations should only modify 3033 * these four fields; the rest will be managed by the CB */ 3034 BlockDriverAmendStatusCB *original_status_cb; 3035 void *original_cb_opaque; 3036 3037 Qcow2AmendOperation current_operation; 3038 3039 /* Total number of operations to perform (only set once) */ 3040 int total_operations; 3041 3042 /* The following fields are managed by the CB */ 3043 3044 /* Number of operations completed */ 3045 int operations_completed; 3046 3047 /* Cumulative offset of all completed operations */ 3048 int64_t offset_completed; 3049 3050 Qcow2AmendOperation last_operation; 3051 int64_t last_work_size; 3052 } Qcow2AmendHelperCBInfo; 3053 3054 static void qcow2_amend_helper_cb(BlockDriverState *bs, 3055 int64_t operation_offset, 3056 int64_t operation_work_size, void *opaque) 3057 { 3058 Qcow2AmendHelperCBInfo *info = opaque; 3059 int64_t current_work_size; 3060 int64_t projected_work_size; 3061 3062 if (info->current_operation != info->last_operation) { 3063 if (info->last_operation != QCOW2_NO_OPERATION) { 3064 info->offset_completed += info->last_work_size; 3065 info->operations_completed++; 3066 } 3067 3068 info->last_operation = info->current_operation; 3069 } 3070 3071 assert(info->total_operations > 0); 3072 assert(info->operations_completed < info->total_operations); 3073 3074 info->last_work_size = operation_work_size; 3075 3076 current_work_size = info->offset_completed + operation_work_size; 3077 3078 /* current_work_size is the total work size for (operations_completed + 1) 3079 * operations (which includes this one), so multiply it by the number of 3080 * operations not covered and divide it by the number of operations 3081 * covered to get a projection for the operations not covered */ 3082 projected_work_size = current_work_size * (info->total_operations - 3083 info->operations_completed - 1) 3084 / (info->operations_completed + 1); 3085 3086 info->original_status_cb(bs, info->offset_completed + operation_offset, 3087 current_work_size + projected_work_size, 3088 info->original_cb_opaque); 3089 } 3090 3091 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3092 BlockDriverAmendStatusCB *status_cb, 3093 void *cb_opaque) 3094 { 3095 BDRVQcow2State *s = bs->opaque; 3096 int old_version = s->qcow_version, new_version = old_version; 3097 uint64_t new_size = 0; 3098 const char *backing_file = NULL, *backing_format = NULL; 3099 bool lazy_refcounts = s->use_lazy_refcounts; 3100 const char *compat = NULL; 3101 uint64_t cluster_size = s->cluster_size; 3102 bool encrypt; 3103 int refcount_bits = s->refcount_bits; 3104 int ret; 3105 QemuOptDesc *desc = opts->list->desc; 3106 Qcow2AmendHelperCBInfo helper_cb_info; 3107 3108 while (desc && desc->name) { 3109 if (!qemu_opt_find(opts, desc->name)) { 3110 /* only change explicitly defined options */ 3111 desc++; 3112 continue; 3113 } 3114 3115 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3116 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3117 if (!compat) { 3118 /* preserve default */ 3119 } else if (!strcmp(compat, "0.10")) { 3120 new_version = 2; 3121 } else if (!strcmp(compat, "1.1")) { 3122 new_version = 3; 3123 } else { 3124 error_report("Unknown compatibility level %s", compat); 3125 return -EINVAL; 3126 } 3127 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3128 error_report("Cannot change preallocation mode"); 3129 return -ENOTSUP; 3130 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3131 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3132 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3133 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3134 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3135 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3136 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3137 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3138 !!s->cipher); 3139 3140 if (encrypt != !!s->cipher) { 3141 error_report("Changing the encryption flag is not supported"); 3142 return -ENOTSUP; 3143 } 3144 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3145 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3146 cluster_size); 3147 if (cluster_size != s->cluster_size) { 3148 error_report("Changing the cluster size is not supported"); 3149 return -ENOTSUP; 3150 } 3151 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3152 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3153 lazy_refcounts); 3154 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3155 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3156 refcount_bits); 3157 3158 if (refcount_bits <= 0 || refcount_bits > 64 || 3159 !is_power_of_2(refcount_bits)) 3160 { 3161 error_report("Refcount width must be a power of two and may " 3162 "not exceed 64 bits"); 3163 return -EINVAL; 3164 } 3165 } else { 3166 /* if this point is reached, this probably means a new option was 3167 * added without having it covered here */ 3168 abort(); 3169 } 3170 3171 desc++; 3172 } 3173 3174 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3175 .original_status_cb = status_cb, 3176 .original_cb_opaque = cb_opaque, 3177 .total_operations = (new_version < old_version) 3178 + (s->refcount_bits != refcount_bits) 3179 }; 3180 3181 /* Upgrade first (some features may require compat=1.1) */ 3182 if (new_version > old_version) { 3183 s->qcow_version = new_version; 3184 ret = qcow2_update_header(bs); 3185 if (ret < 0) { 3186 s->qcow_version = old_version; 3187 return ret; 3188 } 3189 } 3190 3191 if (s->refcount_bits != refcount_bits) { 3192 int refcount_order = ctz32(refcount_bits); 3193 Error *local_error = NULL; 3194 3195 if (new_version < 3 && refcount_bits != 16) { 3196 error_report("Different refcount widths than 16 bits require " 3197 "compatibility level 1.1 or above (use compat=1.1 or " 3198 "greater)"); 3199 return -EINVAL; 3200 } 3201 3202 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3203 ret = qcow2_change_refcount_order(bs, refcount_order, 3204 &qcow2_amend_helper_cb, 3205 &helper_cb_info, &local_error); 3206 if (ret < 0) { 3207 error_report_err(local_error); 3208 return ret; 3209 } 3210 } 3211 3212 if (backing_file || backing_format) { 3213 ret = qcow2_change_backing_file(bs, 3214 backing_file ?: s->image_backing_file, 3215 backing_format ?: s->image_backing_format); 3216 if (ret < 0) { 3217 return ret; 3218 } 3219 } 3220 3221 if (s->use_lazy_refcounts != lazy_refcounts) { 3222 if (lazy_refcounts) { 3223 if (new_version < 3) { 3224 error_report("Lazy refcounts only supported with compatibility " 3225 "level 1.1 and above (use compat=1.1 or greater)"); 3226 return -EINVAL; 3227 } 3228 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3229 ret = qcow2_update_header(bs); 3230 if (ret < 0) { 3231 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3232 return ret; 3233 } 3234 s->use_lazy_refcounts = true; 3235 } else { 3236 /* make image clean first */ 3237 ret = qcow2_mark_clean(bs); 3238 if (ret < 0) { 3239 return ret; 3240 } 3241 /* now disallow lazy refcounts */ 3242 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3243 ret = qcow2_update_header(bs); 3244 if (ret < 0) { 3245 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3246 return ret; 3247 } 3248 s->use_lazy_refcounts = false; 3249 } 3250 } 3251 3252 if (new_size) { 3253 ret = bdrv_truncate(bs, new_size); 3254 if (ret < 0) { 3255 return ret; 3256 } 3257 } 3258 3259 /* Downgrade last (so unsupported features can be removed before) */ 3260 if (new_version < old_version) { 3261 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3262 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3263 &helper_cb_info); 3264 if (ret < 0) { 3265 return ret; 3266 } 3267 } 3268 3269 return 0; 3270 } 3271 3272 /* 3273 * If offset or size are negative, respectively, they will not be included in 3274 * the BLOCK_IMAGE_CORRUPTED event emitted. 3275 * fatal will be ignored for read-only BDS; corruptions found there will always 3276 * be considered non-fatal. 3277 */ 3278 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3279 int64_t size, const char *message_format, ...) 3280 { 3281 BDRVQcow2State *s = bs->opaque; 3282 const char *node_name; 3283 char *message; 3284 va_list ap; 3285 3286 fatal = fatal && !bs->read_only; 3287 3288 if (s->signaled_corruption && 3289 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3290 { 3291 return; 3292 } 3293 3294 va_start(ap, message_format); 3295 message = g_strdup_vprintf(message_format, ap); 3296 va_end(ap); 3297 3298 if (fatal) { 3299 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3300 "corruption events will be suppressed\n", message); 3301 } else { 3302 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3303 "corruption events will be suppressed\n", message); 3304 } 3305 3306 node_name = bdrv_get_node_name(bs); 3307 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3308 *node_name != '\0', node_name, 3309 message, offset >= 0, offset, 3310 size >= 0, size, 3311 fatal, &error_abort); 3312 g_free(message); 3313 3314 if (fatal) { 3315 qcow2_mark_corrupt(bs); 3316 bs->drv = NULL; /* make BDS unusable */ 3317 } 3318 3319 s->signaled_corruption = true; 3320 } 3321 3322 static QemuOptsList qcow2_create_opts = { 3323 .name = "qcow2-create-opts", 3324 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3325 .desc = { 3326 { 3327 .name = BLOCK_OPT_SIZE, 3328 .type = QEMU_OPT_SIZE, 3329 .help = "Virtual disk size" 3330 }, 3331 { 3332 .name = BLOCK_OPT_COMPAT_LEVEL, 3333 .type = QEMU_OPT_STRING, 3334 .help = "Compatibility level (0.10 or 1.1)" 3335 }, 3336 { 3337 .name = BLOCK_OPT_BACKING_FILE, 3338 .type = QEMU_OPT_STRING, 3339 .help = "File name of a base image" 3340 }, 3341 { 3342 .name = BLOCK_OPT_BACKING_FMT, 3343 .type = QEMU_OPT_STRING, 3344 .help = "Image format of the base image" 3345 }, 3346 { 3347 .name = BLOCK_OPT_ENCRYPT, 3348 .type = QEMU_OPT_BOOL, 3349 .help = "Encrypt the image", 3350 .def_value_str = "off" 3351 }, 3352 { 3353 .name = BLOCK_OPT_CLUSTER_SIZE, 3354 .type = QEMU_OPT_SIZE, 3355 .help = "qcow2 cluster size", 3356 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3357 }, 3358 { 3359 .name = BLOCK_OPT_PREALLOC, 3360 .type = QEMU_OPT_STRING, 3361 .help = "Preallocation mode (allowed values: off, metadata, " 3362 "falloc, full)" 3363 }, 3364 { 3365 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3366 .type = QEMU_OPT_BOOL, 3367 .help = "Postpone refcount updates", 3368 .def_value_str = "off" 3369 }, 3370 { 3371 .name = BLOCK_OPT_REFCOUNT_BITS, 3372 .type = QEMU_OPT_NUMBER, 3373 .help = "Width of a reference count entry in bits", 3374 .def_value_str = "16" 3375 }, 3376 { /* end of list */ } 3377 } 3378 }; 3379 3380 BlockDriver bdrv_qcow2 = { 3381 .format_name = "qcow2", 3382 .instance_size = sizeof(BDRVQcow2State), 3383 .bdrv_probe = qcow2_probe, 3384 .bdrv_open = qcow2_open, 3385 .bdrv_close = qcow2_close, 3386 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3387 .bdrv_reopen_commit = qcow2_reopen_commit, 3388 .bdrv_reopen_abort = qcow2_reopen_abort, 3389 .bdrv_join_options = qcow2_join_options, 3390 .bdrv_create = qcow2_create, 3391 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3392 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3393 .bdrv_set_key = qcow2_set_key, 3394 3395 .bdrv_co_preadv = qcow2_co_preadv, 3396 .bdrv_co_pwritev = qcow2_co_pwritev, 3397 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3398 3399 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 3400 .bdrv_co_pdiscard = qcow2_co_pdiscard, 3401 .bdrv_truncate = qcow2_truncate, 3402 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 3403 .bdrv_make_empty = qcow2_make_empty, 3404 3405 .bdrv_snapshot_create = qcow2_snapshot_create, 3406 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3407 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3408 .bdrv_snapshot_list = qcow2_snapshot_list, 3409 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3410 .bdrv_get_info = qcow2_get_info, 3411 .bdrv_get_specific_info = qcow2_get_specific_info, 3412 3413 .bdrv_save_vmstate = qcow2_save_vmstate, 3414 .bdrv_load_vmstate = qcow2_load_vmstate, 3415 3416 .supports_backing = true, 3417 .bdrv_change_backing_file = qcow2_change_backing_file, 3418 3419 .bdrv_refresh_limits = qcow2_refresh_limits, 3420 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3421 .bdrv_inactivate = qcow2_inactivate, 3422 3423 .create_opts = &qcow2_create_opts, 3424 .bdrv_check = qcow2_check, 3425 .bdrv_amend_options = qcow2_amend_options, 3426 3427 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3428 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3429 }; 3430 3431 static void bdrv_qcow2_init(void) 3432 { 3433 bdrv_register(&bdrv_qcow2); 3434 } 3435 3436 block_init(bdrv_qcow2_init); 3437