1 /* 2 * Block driver for the QCOW version 2 format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #include "qemu/osdep.h" 25 #include "qemu-common.h" 26 #include "block/block_int.h" 27 #include "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 39 /* 40 Differences with QCOW: 41 42 - Support for multiple incremental snapshots. 43 - Memory management by reference counts. 44 - Clusters which have a reference count of one have the bit 45 QCOW_OFLAG_COPIED to optimize write performance. 46 - Size of compressed clusters is stored in sectors to reduce bit usage 47 in the cluster offsets. 48 - Support for storing additional data (such as the VM state) in the 49 snapshots. 50 - If a backing store is used, the cluster size is not constrained 51 (could be backported to QCOW). 52 - L2 tables have always a size of one cluster. 53 */ 54 55 56 typedef struct { 57 uint32_t magic; 58 uint32_t len; 59 } QEMU_PACKED QCowExtension; 60 61 #define QCOW2_EXT_MAGIC_END 0 62 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 63 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 64 65 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 66 { 67 const QCowHeader *cow_header = (const void *)buf; 68 69 if (buf_size >= sizeof(QCowHeader) && 70 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 71 be32_to_cpu(cow_header->version) >= 2) 72 return 100; 73 else 74 return 0; 75 } 76 77 78 /* 79 * read qcow2 extension and fill bs 80 * start reading from start_offset 81 * finish reading upon magic of value 0 or when end_offset reached 82 * unknown magic is skipped (future extension this version knows nothing about) 83 * return 0 upon success, non-0 otherwise 84 */ 85 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 86 uint64_t end_offset, void **p_feature_table, 87 Error **errp) 88 { 89 BDRVQcow2State *s = bs->opaque; 90 QCowExtension ext; 91 uint64_t offset; 92 int ret; 93 94 #ifdef DEBUG_EXT 95 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 96 #endif 97 offset = start_offset; 98 while (offset < end_offset) { 99 100 #ifdef DEBUG_EXT 101 /* Sanity check */ 102 if (offset > s->cluster_size) 103 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 104 105 printf("attempting to read extended header in offset %lu\n", offset); 106 #endif 107 108 ret = bdrv_pread(bs->file->bs, offset, &ext, sizeof(ext)); 109 if (ret < 0) { 110 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 111 "pread fail from offset %" PRIu64, offset); 112 return 1; 113 } 114 be32_to_cpus(&ext.magic); 115 be32_to_cpus(&ext.len); 116 offset += sizeof(ext); 117 #ifdef DEBUG_EXT 118 printf("ext.magic = 0x%x\n", ext.magic); 119 #endif 120 if (offset > end_offset || ext.len > end_offset - offset) { 121 error_setg(errp, "Header extension too large"); 122 return -EINVAL; 123 } 124 125 switch (ext.magic) { 126 case QCOW2_EXT_MAGIC_END: 127 return 0; 128 129 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 130 if (ext.len >= sizeof(bs->backing_format)) { 131 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 132 " too large (>=%zu)", ext.len, 133 sizeof(bs->backing_format)); 134 return 2; 135 } 136 ret = bdrv_pread(bs->file->bs, offset, bs->backing_format, ext.len); 137 if (ret < 0) { 138 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 139 "Could not read format name"); 140 return 3; 141 } 142 bs->backing_format[ext.len] = '\0'; 143 s->image_backing_format = g_strdup(bs->backing_format); 144 #ifdef DEBUG_EXT 145 printf("Qcow2: Got format extension %s\n", bs->backing_format); 146 #endif 147 break; 148 149 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 150 if (p_feature_table != NULL) { 151 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 152 ret = bdrv_pread(bs->file->bs, offset , feature_table, ext.len); 153 if (ret < 0) { 154 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 155 "Could not read table"); 156 return ret; 157 } 158 159 *p_feature_table = feature_table; 160 } 161 break; 162 163 default: 164 /* unknown magic - save it in case we need to rewrite the header */ 165 { 166 Qcow2UnknownHeaderExtension *uext; 167 168 uext = g_malloc0(sizeof(*uext) + ext.len); 169 uext->magic = ext.magic; 170 uext->len = ext.len; 171 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 172 173 ret = bdrv_pread(bs->file->bs, offset , uext->data, uext->len); 174 if (ret < 0) { 175 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 176 "Could not read data"); 177 return ret; 178 } 179 } 180 break; 181 } 182 183 offset += ((ext.len + 7) & ~7); 184 } 185 186 return 0; 187 } 188 189 static void cleanup_unknown_header_ext(BlockDriverState *bs) 190 { 191 BDRVQcow2State *s = bs->opaque; 192 Qcow2UnknownHeaderExtension *uext, *next; 193 194 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 195 QLIST_REMOVE(uext, next); 196 g_free(uext); 197 } 198 } 199 200 static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState *bs, 201 Error **errp, const char *fmt, ...) 202 { 203 char msg[64]; 204 va_list ap; 205 206 va_start(ap, fmt); 207 vsnprintf(msg, sizeof(msg), fmt, ap); 208 va_end(ap); 209 210 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 211 bdrv_get_device_or_node_name(bs), "qcow2", msg); 212 } 213 214 static void report_unsupported_feature(BlockDriverState *bs, 215 Error **errp, Qcow2Feature *table, uint64_t mask) 216 { 217 char *features = g_strdup(""); 218 char *old; 219 220 while (table && table->name[0] != '\0') { 221 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 222 if (mask & (1ULL << table->bit)) { 223 old = features; 224 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 225 table->name); 226 g_free(old); 227 mask &= ~(1ULL << table->bit); 228 } 229 } 230 table++; 231 } 232 233 if (mask) { 234 old = features; 235 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 236 old, *old ? ", " : "", mask); 237 g_free(old); 238 } 239 240 report_unsupported(bs, errp, "%s", features); 241 g_free(features); 242 } 243 244 /* 245 * Sets the dirty bit and flushes afterwards if necessary. 246 * 247 * The incompatible_features bit is only set if the image file header was 248 * updated successfully. Therefore it is not required to check the return 249 * value of this function. 250 */ 251 int qcow2_mark_dirty(BlockDriverState *bs) 252 { 253 BDRVQcow2State *s = bs->opaque; 254 uint64_t val; 255 int ret; 256 257 assert(s->qcow_version >= 3); 258 259 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 260 return 0; /* already dirty */ 261 } 262 263 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 264 ret = bdrv_pwrite(bs->file->bs, offsetof(QCowHeader, incompatible_features), 265 &val, sizeof(val)); 266 if (ret < 0) { 267 return ret; 268 } 269 ret = bdrv_flush(bs->file->bs); 270 if (ret < 0) { 271 return ret; 272 } 273 274 /* Only treat image as dirty if the header was updated successfully */ 275 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 276 return 0; 277 } 278 279 /* 280 * Clears the dirty bit and flushes before if necessary. Only call this 281 * function when there are no pending requests, it does not guard against 282 * concurrent requests dirtying the image. 283 */ 284 static int qcow2_mark_clean(BlockDriverState *bs) 285 { 286 BDRVQcow2State *s = bs->opaque; 287 288 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 289 int ret; 290 291 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 292 293 ret = bdrv_flush(bs); 294 if (ret < 0) { 295 return ret; 296 } 297 298 return qcow2_update_header(bs); 299 } 300 return 0; 301 } 302 303 /* 304 * Marks the image as corrupt. 305 */ 306 int qcow2_mark_corrupt(BlockDriverState *bs) 307 { 308 BDRVQcow2State *s = bs->opaque; 309 310 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 311 return qcow2_update_header(bs); 312 } 313 314 /* 315 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 316 * before if necessary. 317 */ 318 int qcow2_mark_consistent(BlockDriverState *bs) 319 { 320 BDRVQcow2State *s = bs->opaque; 321 322 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 323 int ret = bdrv_flush(bs); 324 if (ret < 0) { 325 return ret; 326 } 327 328 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 329 return qcow2_update_header(bs); 330 } 331 return 0; 332 } 333 334 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 335 BdrvCheckMode fix) 336 { 337 int ret = qcow2_check_refcounts(bs, result, fix); 338 if (ret < 0) { 339 return ret; 340 } 341 342 if (fix && result->check_errors == 0 && result->corruptions == 0) { 343 ret = qcow2_mark_clean(bs); 344 if (ret < 0) { 345 return ret; 346 } 347 return qcow2_mark_consistent(bs); 348 } 349 return ret; 350 } 351 352 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 353 uint64_t entries, size_t entry_len) 354 { 355 BDRVQcow2State *s = bs->opaque; 356 uint64_t size; 357 358 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 359 * because values will be passed to qemu functions taking int64_t. */ 360 if (entries > INT64_MAX / entry_len) { 361 return -EINVAL; 362 } 363 364 size = entries * entry_len; 365 366 if (INT64_MAX - size < offset) { 367 return -EINVAL; 368 } 369 370 /* Tables must be cluster aligned */ 371 if (offset & (s->cluster_size - 1)) { 372 return -EINVAL; 373 } 374 375 return 0; 376 } 377 378 static QemuOptsList qcow2_runtime_opts = { 379 .name = "qcow2", 380 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 381 .desc = { 382 { 383 .name = QCOW2_OPT_LAZY_REFCOUNTS, 384 .type = QEMU_OPT_BOOL, 385 .help = "Postpone refcount updates", 386 }, 387 { 388 .name = QCOW2_OPT_DISCARD_REQUEST, 389 .type = QEMU_OPT_BOOL, 390 .help = "Pass guest discard requests to the layer below", 391 }, 392 { 393 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 394 .type = QEMU_OPT_BOOL, 395 .help = "Generate discard requests when snapshot related space " 396 "is freed", 397 }, 398 { 399 .name = QCOW2_OPT_DISCARD_OTHER, 400 .type = QEMU_OPT_BOOL, 401 .help = "Generate discard requests when other clusters are freed", 402 }, 403 { 404 .name = QCOW2_OPT_OVERLAP, 405 .type = QEMU_OPT_STRING, 406 .help = "Selects which overlap checks to perform from a range of " 407 "templates (none, constant, cached, all)", 408 }, 409 { 410 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 411 .type = QEMU_OPT_STRING, 412 .help = "Selects which overlap checks to perform from a range of " 413 "templates (none, constant, cached, all)", 414 }, 415 { 416 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 417 .type = QEMU_OPT_BOOL, 418 .help = "Check for unintended writes into the main qcow2 header", 419 }, 420 { 421 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 422 .type = QEMU_OPT_BOOL, 423 .help = "Check for unintended writes into the active L1 table", 424 }, 425 { 426 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 427 .type = QEMU_OPT_BOOL, 428 .help = "Check for unintended writes into an active L2 table", 429 }, 430 { 431 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 432 .type = QEMU_OPT_BOOL, 433 .help = "Check for unintended writes into the refcount table", 434 }, 435 { 436 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 437 .type = QEMU_OPT_BOOL, 438 .help = "Check for unintended writes into a refcount block", 439 }, 440 { 441 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 442 .type = QEMU_OPT_BOOL, 443 .help = "Check for unintended writes into the snapshot table", 444 }, 445 { 446 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 447 .type = QEMU_OPT_BOOL, 448 .help = "Check for unintended writes into an inactive L1 table", 449 }, 450 { 451 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 452 .type = QEMU_OPT_BOOL, 453 .help = "Check for unintended writes into an inactive L2 table", 454 }, 455 { 456 .name = QCOW2_OPT_CACHE_SIZE, 457 .type = QEMU_OPT_SIZE, 458 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 459 "cache size", 460 }, 461 { 462 .name = QCOW2_OPT_L2_CACHE_SIZE, 463 .type = QEMU_OPT_SIZE, 464 .help = "Maximum L2 table cache size", 465 }, 466 { 467 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 468 .type = QEMU_OPT_SIZE, 469 .help = "Maximum refcount block cache size", 470 }, 471 { 472 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 473 .type = QEMU_OPT_NUMBER, 474 .help = "Clean unused cache entries after this time (in seconds)", 475 }, 476 { /* end of list */ } 477 }, 478 }; 479 480 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 481 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 482 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 483 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 484 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 485 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 486 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 487 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 488 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 489 }; 490 491 static void cache_clean_timer_cb(void *opaque) 492 { 493 BlockDriverState *bs = opaque; 494 BDRVQcow2State *s = bs->opaque; 495 qcow2_cache_clean_unused(bs, s->l2_table_cache); 496 qcow2_cache_clean_unused(bs, s->refcount_block_cache); 497 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 498 (int64_t) s->cache_clean_interval * 1000); 499 } 500 501 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 502 { 503 BDRVQcow2State *s = bs->opaque; 504 if (s->cache_clean_interval > 0) { 505 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 506 SCALE_MS, cache_clean_timer_cb, 507 bs); 508 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 509 (int64_t) s->cache_clean_interval * 1000); 510 } 511 } 512 513 static void cache_clean_timer_del(BlockDriverState *bs) 514 { 515 BDRVQcow2State *s = bs->opaque; 516 if (s->cache_clean_timer) { 517 timer_del(s->cache_clean_timer); 518 timer_free(s->cache_clean_timer); 519 s->cache_clean_timer = NULL; 520 } 521 } 522 523 static void qcow2_detach_aio_context(BlockDriverState *bs) 524 { 525 cache_clean_timer_del(bs); 526 } 527 528 static void qcow2_attach_aio_context(BlockDriverState *bs, 529 AioContext *new_context) 530 { 531 cache_clean_timer_init(bs, new_context); 532 } 533 534 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 535 uint64_t *l2_cache_size, 536 uint64_t *refcount_cache_size, Error **errp) 537 { 538 BDRVQcow2State *s = bs->opaque; 539 uint64_t combined_cache_size; 540 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 541 542 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 543 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 544 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 545 546 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 547 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 548 *refcount_cache_size = qemu_opt_get_size(opts, 549 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 550 551 if (combined_cache_size_set) { 552 if (l2_cache_size_set && refcount_cache_size_set) { 553 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 554 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 555 "the same time"); 556 return; 557 } else if (*l2_cache_size > combined_cache_size) { 558 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 559 QCOW2_OPT_CACHE_SIZE); 560 return; 561 } else if (*refcount_cache_size > combined_cache_size) { 562 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 563 QCOW2_OPT_CACHE_SIZE); 564 return; 565 } 566 567 if (l2_cache_size_set) { 568 *refcount_cache_size = combined_cache_size - *l2_cache_size; 569 } else if (refcount_cache_size_set) { 570 *l2_cache_size = combined_cache_size - *refcount_cache_size; 571 } else { 572 *refcount_cache_size = combined_cache_size 573 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 574 *l2_cache_size = combined_cache_size - *refcount_cache_size; 575 } 576 } else { 577 if (!l2_cache_size_set && !refcount_cache_size_set) { 578 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 579 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 580 * s->cluster_size); 581 *refcount_cache_size = *l2_cache_size 582 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 583 } else if (!l2_cache_size_set) { 584 *l2_cache_size = *refcount_cache_size 585 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 586 } else if (!refcount_cache_size_set) { 587 *refcount_cache_size = *l2_cache_size 588 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 589 } 590 } 591 } 592 593 typedef struct Qcow2ReopenState { 594 Qcow2Cache *l2_table_cache; 595 Qcow2Cache *refcount_block_cache; 596 bool use_lazy_refcounts; 597 int overlap_check; 598 bool discard_passthrough[QCOW2_DISCARD_MAX]; 599 uint64_t cache_clean_interval; 600 } Qcow2ReopenState; 601 602 static int qcow2_update_options_prepare(BlockDriverState *bs, 603 Qcow2ReopenState *r, 604 QDict *options, int flags, 605 Error **errp) 606 { 607 BDRVQcow2State *s = bs->opaque; 608 QemuOpts *opts = NULL; 609 const char *opt_overlap_check, *opt_overlap_check_template; 610 int overlap_check_template = 0; 611 uint64_t l2_cache_size, refcount_cache_size; 612 int i; 613 Error *local_err = NULL; 614 int ret; 615 616 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 617 qemu_opts_absorb_qdict(opts, options, &local_err); 618 if (local_err) { 619 error_propagate(errp, local_err); 620 ret = -EINVAL; 621 goto fail; 622 } 623 624 /* get L2 table/refcount block cache size from command line options */ 625 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 626 &local_err); 627 if (local_err) { 628 error_propagate(errp, local_err); 629 ret = -EINVAL; 630 goto fail; 631 } 632 633 l2_cache_size /= s->cluster_size; 634 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 635 l2_cache_size = MIN_L2_CACHE_SIZE; 636 } 637 if (l2_cache_size > INT_MAX) { 638 error_setg(errp, "L2 cache size too big"); 639 ret = -EINVAL; 640 goto fail; 641 } 642 643 refcount_cache_size /= s->cluster_size; 644 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 645 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 646 } 647 if (refcount_cache_size > INT_MAX) { 648 error_setg(errp, "Refcount cache size too big"); 649 ret = -EINVAL; 650 goto fail; 651 } 652 653 /* alloc new L2 table/refcount block cache, flush old one */ 654 if (s->l2_table_cache) { 655 ret = qcow2_cache_flush(bs, s->l2_table_cache); 656 if (ret) { 657 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 658 goto fail; 659 } 660 } 661 662 if (s->refcount_block_cache) { 663 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 664 if (ret) { 665 error_setg_errno(errp, -ret, 666 "Failed to flush the refcount block cache"); 667 goto fail; 668 } 669 } 670 671 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 672 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 673 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 674 error_setg(errp, "Could not allocate metadata caches"); 675 ret = -ENOMEM; 676 goto fail; 677 } 678 679 /* New interval for cache cleanup timer */ 680 r->cache_clean_interval = 681 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 682 s->cache_clean_interval); 683 if (r->cache_clean_interval > UINT_MAX) { 684 error_setg(errp, "Cache clean interval too big"); 685 ret = -EINVAL; 686 goto fail; 687 } 688 689 /* lazy-refcounts; flush if going from enabled to disabled */ 690 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 691 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 692 if (r->use_lazy_refcounts && s->qcow_version < 3) { 693 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 694 "qemu 1.1 compatibility level"); 695 ret = -EINVAL; 696 goto fail; 697 } 698 699 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 700 ret = qcow2_mark_clean(bs); 701 if (ret < 0) { 702 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 703 goto fail; 704 } 705 } 706 707 /* Overlap check options */ 708 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 709 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 710 if (opt_overlap_check_template && opt_overlap_check && 711 strcmp(opt_overlap_check_template, opt_overlap_check)) 712 { 713 error_setg(errp, "Conflicting values for qcow2 options '" 714 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 715 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 716 ret = -EINVAL; 717 goto fail; 718 } 719 if (!opt_overlap_check) { 720 opt_overlap_check = opt_overlap_check_template ?: "cached"; 721 } 722 723 if (!strcmp(opt_overlap_check, "none")) { 724 overlap_check_template = 0; 725 } else if (!strcmp(opt_overlap_check, "constant")) { 726 overlap_check_template = QCOW2_OL_CONSTANT; 727 } else if (!strcmp(opt_overlap_check, "cached")) { 728 overlap_check_template = QCOW2_OL_CACHED; 729 } else if (!strcmp(opt_overlap_check, "all")) { 730 overlap_check_template = QCOW2_OL_ALL; 731 } else { 732 error_setg(errp, "Unsupported value '%s' for qcow2 option " 733 "'overlap-check'. Allowed are any of the following: " 734 "none, constant, cached, all", opt_overlap_check); 735 ret = -EINVAL; 736 goto fail; 737 } 738 739 r->overlap_check = 0; 740 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 741 /* overlap-check defines a template bitmask, but every flag may be 742 * overwritten through the associated boolean option */ 743 r->overlap_check |= 744 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 745 overlap_check_template & (1 << i)) << i; 746 } 747 748 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 749 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 750 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 751 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 752 flags & BDRV_O_UNMAP); 753 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 754 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 755 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 756 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 757 758 ret = 0; 759 fail: 760 qemu_opts_del(opts); 761 opts = NULL; 762 return ret; 763 } 764 765 static void qcow2_update_options_commit(BlockDriverState *bs, 766 Qcow2ReopenState *r) 767 { 768 BDRVQcow2State *s = bs->opaque; 769 int i; 770 771 if (s->l2_table_cache) { 772 qcow2_cache_destroy(bs, s->l2_table_cache); 773 } 774 if (s->refcount_block_cache) { 775 qcow2_cache_destroy(bs, s->refcount_block_cache); 776 } 777 s->l2_table_cache = r->l2_table_cache; 778 s->refcount_block_cache = r->refcount_block_cache; 779 780 s->overlap_check = r->overlap_check; 781 s->use_lazy_refcounts = r->use_lazy_refcounts; 782 783 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 784 s->discard_passthrough[i] = r->discard_passthrough[i]; 785 } 786 787 if (s->cache_clean_interval != r->cache_clean_interval) { 788 cache_clean_timer_del(bs); 789 s->cache_clean_interval = r->cache_clean_interval; 790 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 791 } 792 } 793 794 static void qcow2_update_options_abort(BlockDriverState *bs, 795 Qcow2ReopenState *r) 796 { 797 if (r->l2_table_cache) { 798 qcow2_cache_destroy(bs, r->l2_table_cache); 799 } 800 if (r->refcount_block_cache) { 801 qcow2_cache_destroy(bs, r->refcount_block_cache); 802 } 803 } 804 805 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 806 int flags, Error **errp) 807 { 808 Qcow2ReopenState r = {}; 809 int ret; 810 811 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 812 if (ret >= 0) { 813 qcow2_update_options_commit(bs, &r); 814 } else { 815 qcow2_update_options_abort(bs, &r); 816 } 817 818 return ret; 819 } 820 821 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 822 Error **errp) 823 { 824 BDRVQcow2State *s = bs->opaque; 825 unsigned int len, i; 826 int ret = 0; 827 QCowHeader header; 828 Error *local_err = NULL; 829 uint64_t ext_end; 830 uint64_t l1_vm_state_index; 831 832 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 833 if (ret < 0) { 834 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 835 goto fail; 836 } 837 be32_to_cpus(&header.magic); 838 be32_to_cpus(&header.version); 839 be64_to_cpus(&header.backing_file_offset); 840 be32_to_cpus(&header.backing_file_size); 841 be64_to_cpus(&header.size); 842 be32_to_cpus(&header.cluster_bits); 843 be32_to_cpus(&header.crypt_method); 844 be64_to_cpus(&header.l1_table_offset); 845 be32_to_cpus(&header.l1_size); 846 be64_to_cpus(&header.refcount_table_offset); 847 be32_to_cpus(&header.refcount_table_clusters); 848 be64_to_cpus(&header.snapshots_offset); 849 be32_to_cpus(&header.nb_snapshots); 850 851 if (header.magic != QCOW_MAGIC) { 852 error_setg(errp, "Image is not in qcow2 format"); 853 ret = -EINVAL; 854 goto fail; 855 } 856 if (header.version < 2 || header.version > 3) { 857 report_unsupported(bs, errp, "QCOW version %" PRIu32, header.version); 858 ret = -ENOTSUP; 859 goto fail; 860 } 861 862 s->qcow_version = header.version; 863 864 /* Initialise cluster size */ 865 if (header.cluster_bits < MIN_CLUSTER_BITS || 866 header.cluster_bits > MAX_CLUSTER_BITS) { 867 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 868 header.cluster_bits); 869 ret = -EINVAL; 870 goto fail; 871 } 872 873 s->cluster_bits = header.cluster_bits; 874 s->cluster_size = 1 << s->cluster_bits; 875 s->cluster_sectors = 1 << (s->cluster_bits - 9); 876 877 /* Initialise version 3 header fields */ 878 if (header.version == 2) { 879 header.incompatible_features = 0; 880 header.compatible_features = 0; 881 header.autoclear_features = 0; 882 header.refcount_order = 4; 883 header.header_length = 72; 884 } else { 885 be64_to_cpus(&header.incompatible_features); 886 be64_to_cpus(&header.compatible_features); 887 be64_to_cpus(&header.autoclear_features); 888 be32_to_cpus(&header.refcount_order); 889 be32_to_cpus(&header.header_length); 890 891 if (header.header_length < 104) { 892 error_setg(errp, "qcow2 header too short"); 893 ret = -EINVAL; 894 goto fail; 895 } 896 } 897 898 if (header.header_length > s->cluster_size) { 899 error_setg(errp, "qcow2 header exceeds cluster size"); 900 ret = -EINVAL; 901 goto fail; 902 } 903 904 if (header.header_length > sizeof(header)) { 905 s->unknown_header_fields_size = header.header_length - sizeof(header); 906 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 907 ret = bdrv_pread(bs->file->bs, sizeof(header), s->unknown_header_fields, 908 s->unknown_header_fields_size); 909 if (ret < 0) { 910 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 911 "fields"); 912 goto fail; 913 } 914 } 915 916 if (header.backing_file_offset > s->cluster_size) { 917 error_setg(errp, "Invalid backing file offset"); 918 ret = -EINVAL; 919 goto fail; 920 } 921 922 if (header.backing_file_offset) { 923 ext_end = header.backing_file_offset; 924 } else { 925 ext_end = 1 << header.cluster_bits; 926 } 927 928 /* Handle feature bits */ 929 s->incompatible_features = header.incompatible_features; 930 s->compatible_features = header.compatible_features; 931 s->autoclear_features = header.autoclear_features; 932 933 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 934 void *feature_table = NULL; 935 qcow2_read_extensions(bs, header.header_length, ext_end, 936 &feature_table, NULL); 937 report_unsupported_feature(bs, errp, feature_table, 938 s->incompatible_features & 939 ~QCOW2_INCOMPAT_MASK); 940 ret = -ENOTSUP; 941 g_free(feature_table); 942 goto fail; 943 } 944 945 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 946 /* Corrupt images may not be written to unless they are being repaired 947 */ 948 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 949 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 950 "read/write"); 951 ret = -EACCES; 952 goto fail; 953 } 954 } 955 956 /* Check support for various header values */ 957 if (header.refcount_order > 6) { 958 error_setg(errp, "Reference count entry width too large; may not " 959 "exceed 64 bits"); 960 ret = -EINVAL; 961 goto fail; 962 } 963 s->refcount_order = header.refcount_order; 964 s->refcount_bits = 1 << s->refcount_order; 965 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 966 s->refcount_max += s->refcount_max - 1; 967 968 if (header.crypt_method > QCOW_CRYPT_AES) { 969 error_setg(errp, "Unsupported encryption method: %" PRIu32, 970 header.crypt_method); 971 ret = -EINVAL; 972 goto fail; 973 } 974 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 975 error_setg(errp, "AES cipher not available"); 976 ret = -EINVAL; 977 goto fail; 978 } 979 s->crypt_method_header = header.crypt_method; 980 if (s->crypt_method_header) { 981 bs->encrypted = 1; 982 } 983 984 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 985 s->l2_size = 1 << s->l2_bits; 986 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 987 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 988 s->refcount_block_size = 1 << s->refcount_block_bits; 989 bs->total_sectors = header.size / 512; 990 s->csize_shift = (62 - (s->cluster_bits - 8)); 991 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 992 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 993 994 s->refcount_table_offset = header.refcount_table_offset; 995 s->refcount_table_size = 996 header.refcount_table_clusters << (s->cluster_bits - 3); 997 998 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 999 error_setg(errp, "Reference count table too large"); 1000 ret = -EINVAL; 1001 goto fail; 1002 } 1003 1004 ret = validate_table_offset(bs, s->refcount_table_offset, 1005 s->refcount_table_size, sizeof(uint64_t)); 1006 if (ret < 0) { 1007 error_setg(errp, "Invalid reference count table offset"); 1008 goto fail; 1009 } 1010 1011 /* Snapshot table offset/length */ 1012 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1013 error_setg(errp, "Too many snapshots"); 1014 ret = -EINVAL; 1015 goto fail; 1016 } 1017 1018 ret = validate_table_offset(bs, header.snapshots_offset, 1019 header.nb_snapshots, 1020 sizeof(QCowSnapshotHeader)); 1021 if (ret < 0) { 1022 error_setg(errp, "Invalid snapshot table offset"); 1023 goto fail; 1024 } 1025 1026 /* read the level 1 table */ 1027 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1028 error_setg(errp, "Active L1 table too large"); 1029 ret = -EFBIG; 1030 goto fail; 1031 } 1032 s->l1_size = header.l1_size; 1033 1034 l1_vm_state_index = size_to_l1(s, header.size); 1035 if (l1_vm_state_index > INT_MAX) { 1036 error_setg(errp, "Image is too big"); 1037 ret = -EFBIG; 1038 goto fail; 1039 } 1040 s->l1_vm_state_index = l1_vm_state_index; 1041 1042 /* the L1 table must contain at least enough entries to put 1043 header.size bytes */ 1044 if (s->l1_size < s->l1_vm_state_index) { 1045 error_setg(errp, "L1 table is too small"); 1046 ret = -EINVAL; 1047 goto fail; 1048 } 1049 1050 ret = validate_table_offset(bs, header.l1_table_offset, 1051 header.l1_size, sizeof(uint64_t)); 1052 if (ret < 0) { 1053 error_setg(errp, "Invalid L1 table offset"); 1054 goto fail; 1055 } 1056 s->l1_table_offset = header.l1_table_offset; 1057 1058 1059 if (s->l1_size > 0) { 1060 s->l1_table = qemu_try_blockalign(bs->file->bs, 1061 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1062 if (s->l1_table == NULL) { 1063 error_setg(errp, "Could not allocate L1 table"); 1064 ret = -ENOMEM; 1065 goto fail; 1066 } 1067 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 1068 s->l1_size * sizeof(uint64_t)); 1069 if (ret < 0) { 1070 error_setg_errno(errp, -ret, "Could not read L1 table"); 1071 goto fail; 1072 } 1073 for(i = 0;i < s->l1_size; i++) { 1074 be64_to_cpus(&s->l1_table[i]); 1075 } 1076 } 1077 1078 /* Parse driver-specific options */ 1079 ret = qcow2_update_options(bs, options, flags, errp); 1080 if (ret < 0) { 1081 goto fail; 1082 } 1083 1084 s->cluster_cache = g_malloc(s->cluster_size); 1085 /* one more sector for decompressed data alignment */ 1086 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1087 * s->cluster_size + 512); 1088 if (s->cluster_data == NULL) { 1089 error_setg(errp, "Could not allocate temporary cluster buffer"); 1090 ret = -ENOMEM; 1091 goto fail; 1092 } 1093 1094 s->cluster_cache_offset = -1; 1095 s->flags = flags; 1096 1097 ret = qcow2_refcount_init(bs); 1098 if (ret != 0) { 1099 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1100 goto fail; 1101 } 1102 1103 QLIST_INIT(&s->cluster_allocs); 1104 QTAILQ_INIT(&s->discards); 1105 1106 /* read qcow2 extensions */ 1107 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1108 &local_err)) { 1109 error_propagate(errp, local_err); 1110 ret = -EINVAL; 1111 goto fail; 1112 } 1113 1114 /* read the backing file name */ 1115 if (header.backing_file_offset != 0) { 1116 len = header.backing_file_size; 1117 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1118 len >= sizeof(bs->backing_file)) { 1119 error_setg(errp, "Backing file name too long"); 1120 ret = -EINVAL; 1121 goto fail; 1122 } 1123 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 1124 bs->backing_file, len); 1125 if (ret < 0) { 1126 error_setg_errno(errp, -ret, "Could not read backing file name"); 1127 goto fail; 1128 } 1129 bs->backing_file[len] = '\0'; 1130 s->image_backing_file = g_strdup(bs->backing_file); 1131 } 1132 1133 /* Internal snapshots */ 1134 s->snapshots_offset = header.snapshots_offset; 1135 s->nb_snapshots = header.nb_snapshots; 1136 1137 ret = qcow2_read_snapshots(bs); 1138 if (ret < 0) { 1139 error_setg_errno(errp, -ret, "Could not read snapshots"); 1140 goto fail; 1141 } 1142 1143 /* Clear unknown autoclear feature bits */ 1144 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { 1145 s->autoclear_features = 0; 1146 ret = qcow2_update_header(bs); 1147 if (ret < 0) { 1148 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1149 goto fail; 1150 } 1151 } 1152 1153 /* Initialise locks */ 1154 qemu_co_mutex_init(&s->lock); 1155 1156 /* Repair image if dirty */ 1157 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1158 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1159 BdrvCheckResult result = {0}; 1160 1161 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1162 if (ret < 0) { 1163 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1164 goto fail; 1165 } 1166 } 1167 1168 #ifdef DEBUG_ALLOC 1169 { 1170 BdrvCheckResult result = {0}; 1171 qcow2_check_refcounts(bs, &result, 0); 1172 } 1173 #endif 1174 return ret; 1175 1176 fail: 1177 g_free(s->unknown_header_fields); 1178 cleanup_unknown_header_ext(bs); 1179 qcow2_free_snapshots(bs); 1180 qcow2_refcount_close(bs); 1181 qemu_vfree(s->l1_table); 1182 /* else pre-write overlap checks in cache_destroy may crash */ 1183 s->l1_table = NULL; 1184 cache_clean_timer_del(bs); 1185 if (s->l2_table_cache) { 1186 qcow2_cache_destroy(bs, s->l2_table_cache); 1187 } 1188 if (s->refcount_block_cache) { 1189 qcow2_cache_destroy(bs, s->refcount_block_cache); 1190 } 1191 g_free(s->cluster_cache); 1192 qemu_vfree(s->cluster_data); 1193 return ret; 1194 } 1195 1196 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1197 { 1198 BDRVQcow2State *s = bs->opaque; 1199 1200 bs->bl.write_zeroes_alignment = s->cluster_sectors; 1201 } 1202 1203 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1204 { 1205 BDRVQcow2State *s = bs->opaque; 1206 uint8_t keybuf[16]; 1207 int len, i; 1208 Error *err = NULL; 1209 1210 memset(keybuf, 0, 16); 1211 len = strlen(key); 1212 if (len > 16) 1213 len = 16; 1214 /* XXX: we could compress the chars to 7 bits to increase 1215 entropy */ 1216 for(i = 0;i < len;i++) { 1217 keybuf[i] = key[i]; 1218 } 1219 assert(bs->encrypted); 1220 1221 qcrypto_cipher_free(s->cipher); 1222 s->cipher = qcrypto_cipher_new( 1223 QCRYPTO_CIPHER_ALG_AES_128, 1224 QCRYPTO_CIPHER_MODE_CBC, 1225 keybuf, G_N_ELEMENTS(keybuf), 1226 &err); 1227 1228 if (!s->cipher) { 1229 /* XXX would be nice if errors in this method could 1230 * be properly propagate to the caller. Would need 1231 * the bdrv_set_key() API signature to be fixed. */ 1232 error_free(err); 1233 return -1; 1234 } 1235 return 0; 1236 } 1237 1238 static int qcow2_reopen_prepare(BDRVReopenState *state, 1239 BlockReopenQueue *queue, Error **errp) 1240 { 1241 Qcow2ReopenState *r; 1242 int ret; 1243 1244 r = g_new0(Qcow2ReopenState, 1); 1245 state->opaque = r; 1246 1247 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1248 state->flags, errp); 1249 if (ret < 0) { 1250 goto fail; 1251 } 1252 1253 /* We need to write out any unwritten data if we reopen read-only. */ 1254 if ((state->flags & BDRV_O_RDWR) == 0) { 1255 ret = bdrv_flush(state->bs); 1256 if (ret < 0) { 1257 goto fail; 1258 } 1259 1260 ret = qcow2_mark_clean(state->bs); 1261 if (ret < 0) { 1262 goto fail; 1263 } 1264 } 1265 1266 return 0; 1267 1268 fail: 1269 qcow2_update_options_abort(state->bs, r); 1270 g_free(r); 1271 return ret; 1272 } 1273 1274 static void qcow2_reopen_commit(BDRVReopenState *state) 1275 { 1276 qcow2_update_options_commit(state->bs, state->opaque); 1277 g_free(state->opaque); 1278 } 1279 1280 static void qcow2_reopen_abort(BDRVReopenState *state) 1281 { 1282 qcow2_update_options_abort(state->bs, state->opaque); 1283 g_free(state->opaque); 1284 } 1285 1286 static void qcow2_join_options(QDict *options, QDict *old_options) 1287 { 1288 bool has_new_overlap_template = 1289 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1290 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1291 bool has_new_total_cache_size = 1292 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1293 bool has_all_cache_options; 1294 1295 /* New overlap template overrides all old overlap options */ 1296 if (has_new_overlap_template) { 1297 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1298 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1299 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1300 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1301 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1302 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1303 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1304 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1305 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1306 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1307 } 1308 1309 /* New total cache size overrides all old options */ 1310 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1311 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1312 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1313 } 1314 1315 qdict_join(options, old_options, false); 1316 1317 /* 1318 * If after merging all cache size options are set, an old total size is 1319 * overwritten. Do keep all options, however, if all three are new. The 1320 * resulting error message is what we want to happen. 1321 */ 1322 has_all_cache_options = 1323 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1324 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1325 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1326 1327 if (has_all_cache_options && !has_new_total_cache_size) { 1328 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1329 } 1330 } 1331 1332 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1333 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1334 { 1335 BDRVQcow2State *s = bs->opaque; 1336 uint64_t cluster_offset; 1337 int index_in_cluster, ret; 1338 int64_t status = 0; 1339 1340 *pnum = nb_sectors; 1341 qemu_co_mutex_lock(&s->lock); 1342 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset); 1343 qemu_co_mutex_unlock(&s->lock); 1344 if (ret < 0) { 1345 return ret; 1346 } 1347 1348 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1349 !s->cipher) { 1350 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1351 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1352 *file = bs->file->bs; 1353 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1354 } 1355 if (ret == QCOW2_CLUSTER_ZERO) { 1356 status |= BDRV_BLOCK_ZERO; 1357 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1358 status |= BDRV_BLOCK_DATA; 1359 } 1360 return status; 1361 } 1362 1363 /* handle reading after the end of the backing file */ 1364 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1365 int64_t sector_num, int nb_sectors) 1366 { 1367 int n1; 1368 if ((sector_num + nb_sectors) <= bs->total_sectors) 1369 return nb_sectors; 1370 if (sector_num >= bs->total_sectors) 1371 n1 = 0; 1372 else 1373 n1 = bs->total_sectors - sector_num; 1374 1375 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1376 1377 return n1; 1378 } 1379 1380 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1381 int remaining_sectors, QEMUIOVector *qiov) 1382 { 1383 BDRVQcow2State *s = bs->opaque; 1384 int index_in_cluster, n1; 1385 int ret; 1386 int cur_nr_sectors; /* number of sectors in current iteration */ 1387 uint64_t cluster_offset = 0; 1388 uint64_t bytes_done = 0; 1389 QEMUIOVector hd_qiov; 1390 uint8_t *cluster_data = NULL; 1391 1392 qemu_iovec_init(&hd_qiov, qiov->niov); 1393 1394 qemu_co_mutex_lock(&s->lock); 1395 1396 while (remaining_sectors != 0) { 1397 1398 /* prepare next request */ 1399 cur_nr_sectors = remaining_sectors; 1400 if (s->cipher) { 1401 cur_nr_sectors = MIN(cur_nr_sectors, 1402 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1403 } 1404 1405 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1406 &cur_nr_sectors, &cluster_offset); 1407 if (ret < 0) { 1408 goto fail; 1409 } 1410 1411 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1412 1413 qemu_iovec_reset(&hd_qiov); 1414 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1415 cur_nr_sectors * 512); 1416 1417 switch (ret) { 1418 case QCOW2_CLUSTER_UNALLOCATED: 1419 1420 if (bs->backing) { 1421 /* read from the base image */ 1422 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1423 sector_num, cur_nr_sectors); 1424 if (n1 > 0) { 1425 QEMUIOVector local_qiov; 1426 1427 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1428 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1429 n1 * BDRV_SECTOR_SIZE); 1430 1431 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1432 qemu_co_mutex_unlock(&s->lock); 1433 ret = bdrv_co_readv(bs->backing->bs, sector_num, 1434 n1, &local_qiov); 1435 qemu_co_mutex_lock(&s->lock); 1436 1437 qemu_iovec_destroy(&local_qiov); 1438 1439 if (ret < 0) { 1440 goto fail; 1441 } 1442 } 1443 } else { 1444 /* Note: in this case, no need to wait */ 1445 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1446 } 1447 break; 1448 1449 case QCOW2_CLUSTER_ZERO: 1450 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1451 break; 1452 1453 case QCOW2_CLUSTER_COMPRESSED: 1454 /* add AIO support for compressed blocks ? */ 1455 ret = qcow2_decompress_cluster(bs, cluster_offset); 1456 if (ret < 0) { 1457 goto fail; 1458 } 1459 1460 qemu_iovec_from_buf(&hd_qiov, 0, 1461 s->cluster_cache + index_in_cluster * 512, 1462 512 * cur_nr_sectors); 1463 break; 1464 1465 case QCOW2_CLUSTER_NORMAL: 1466 if ((cluster_offset & 511) != 0) { 1467 ret = -EIO; 1468 goto fail; 1469 } 1470 1471 if (bs->encrypted) { 1472 assert(s->cipher); 1473 1474 /* 1475 * For encrypted images, read everything into a temporary 1476 * contiguous buffer on which the AES functions can work. 1477 */ 1478 if (!cluster_data) { 1479 cluster_data = 1480 qemu_try_blockalign(bs->file->bs, 1481 QCOW_MAX_CRYPT_CLUSTERS 1482 * s->cluster_size); 1483 if (cluster_data == NULL) { 1484 ret = -ENOMEM; 1485 goto fail; 1486 } 1487 } 1488 1489 assert(cur_nr_sectors <= 1490 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1491 qemu_iovec_reset(&hd_qiov); 1492 qemu_iovec_add(&hd_qiov, cluster_data, 1493 512 * cur_nr_sectors); 1494 } 1495 1496 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1497 qemu_co_mutex_unlock(&s->lock); 1498 ret = bdrv_co_readv(bs->file->bs, 1499 (cluster_offset >> 9) + index_in_cluster, 1500 cur_nr_sectors, &hd_qiov); 1501 qemu_co_mutex_lock(&s->lock); 1502 if (ret < 0) { 1503 goto fail; 1504 } 1505 if (bs->encrypted) { 1506 assert(s->cipher); 1507 Error *err = NULL; 1508 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1509 cluster_data, cur_nr_sectors, false, 1510 &err) < 0) { 1511 error_free(err); 1512 ret = -EIO; 1513 goto fail; 1514 } 1515 qemu_iovec_from_buf(qiov, bytes_done, 1516 cluster_data, 512 * cur_nr_sectors); 1517 } 1518 break; 1519 1520 default: 1521 g_assert_not_reached(); 1522 ret = -EIO; 1523 goto fail; 1524 } 1525 1526 remaining_sectors -= cur_nr_sectors; 1527 sector_num += cur_nr_sectors; 1528 bytes_done += cur_nr_sectors * 512; 1529 } 1530 ret = 0; 1531 1532 fail: 1533 qemu_co_mutex_unlock(&s->lock); 1534 1535 qemu_iovec_destroy(&hd_qiov); 1536 qemu_vfree(cluster_data); 1537 1538 return ret; 1539 } 1540 1541 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1542 int64_t sector_num, 1543 int remaining_sectors, 1544 QEMUIOVector *qiov) 1545 { 1546 BDRVQcow2State *s = bs->opaque; 1547 int index_in_cluster; 1548 int ret; 1549 int cur_nr_sectors; /* number of sectors in current iteration */ 1550 uint64_t cluster_offset; 1551 QEMUIOVector hd_qiov; 1552 uint64_t bytes_done = 0; 1553 uint8_t *cluster_data = NULL; 1554 QCowL2Meta *l2meta = NULL; 1555 1556 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1557 remaining_sectors); 1558 1559 qemu_iovec_init(&hd_qiov, qiov->niov); 1560 1561 s->cluster_cache_offset = -1; /* disable compressed cache */ 1562 1563 qemu_co_mutex_lock(&s->lock); 1564 1565 while (remaining_sectors != 0) { 1566 1567 l2meta = NULL; 1568 1569 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1570 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1571 cur_nr_sectors = remaining_sectors; 1572 if (bs->encrypted && 1573 cur_nr_sectors > 1574 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1575 cur_nr_sectors = 1576 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1577 } 1578 1579 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1580 &cur_nr_sectors, &cluster_offset, &l2meta); 1581 if (ret < 0) { 1582 goto fail; 1583 } 1584 1585 assert((cluster_offset & 511) == 0); 1586 1587 qemu_iovec_reset(&hd_qiov); 1588 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1589 cur_nr_sectors * 512); 1590 1591 if (bs->encrypted) { 1592 Error *err = NULL; 1593 assert(s->cipher); 1594 if (!cluster_data) { 1595 cluster_data = qemu_try_blockalign(bs->file->bs, 1596 QCOW_MAX_CRYPT_CLUSTERS 1597 * s->cluster_size); 1598 if (cluster_data == NULL) { 1599 ret = -ENOMEM; 1600 goto fail; 1601 } 1602 } 1603 1604 assert(hd_qiov.size <= 1605 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1606 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1607 1608 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1609 cluster_data, cur_nr_sectors, 1610 true, &err) < 0) { 1611 error_free(err); 1612 ret = -EIO; 1613 goto fail; 1614 } 1615 1616 qemu_iovec_reset(&hd_qiov); 1617 qemu_iovec_add(&hd_qiov, cluster_data, 1618 cur_nr_sectors * 512); 1619 } 1620 1621 ret = qcow2_pre_write_overlap_check(bs, 0, 1622 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1623 cur_nr_sectors * BDRV_SECTOR_SIZE); 1624 if (ret < 0) { 1625 goto fail; 1626 } 1627 1628 qemu_co_mutex_unlock(&s->lock); 1629 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1630 trace_qcow2_writev_data(qemu_coroutine_self(), 1631 (cluster_offset >> 9) + index_in_cluster); 1632 ret = bdrv_co_writev(bs->file->bs, 1633 (cluster_offset >> 9) + index_in_cluster, 1634 cur_nr_sectors, &hd_qiov); 1635 qemu_co_mutex_lock(&s->lock); 1636 if (ret < 0) { 1637 goto fail; 1638 } 1639 1640 while (l2meta != NULL) { 1641 QCowL2Meta *next; 1642 1643 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1644 if (ret < 0) { 1645 goto fail; 1646 } 1647 1648 /* Take the request off the list of running requests */ 1649 if (l2meta->nb_clusters != 0) { 1650 QLIST_REMOVE(l2meta, next_in_flight); 1651 } 1652 1653 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1654 1655 next = l2meta->next; 1656 g_free(l2meta); 1657 l2meta = next; 1658 } 1659 1660 remaining_sectors -= cur_nr_sectors; 1661 sector_num += cur_nr_sectors; 1662 bytes_done += cur_nr_sectors * 512; 1663 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1664 } 1665 ret = 0; 1666 1667 fail: 1668 qemu_co_mutex_unlock(&s->lock); 1669 1670 while (l2meta != NULL) { 1671 QCowL2Meta *next; 1672 1673 if (l2meta->nb_clusters != 0) { 1674 QLIST_REMOVE(l2meta, next_in_flight); 1675 } 1676 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1677 1678 next = l2meta->next; 1679 g_free(l2meta); 1680 l2meta = next; 1681 } 1682 1683 qemu_iovec_destroy(&hd_qiov); 1684 qemu_vfree(cluster_data); 1685 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1686 1687 return ret; 1688 } 1689 1690 static int qcow2_inactivate(BlockDriverState *bs) 1691 { 1692 BDRVQcow2State *s = bs->opaque; 1693 int ret, result = 0; 1694 1695 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1696 if (ret) { 1697 result = ret; 1698 error_report("Failed to flush the L2 table cache: %s", 1699 strerror(-ret)); 1700 } 1701 1702 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1703 if (ret) { 1704 result = ret; 1705 error_report("Failed to flush the refcount block cache: %s", 1706 strerror(-ret)); 1707 } 1708 1709 if (result == 0) { 1710 qcow2_mark_clean(bs); 1711 } 1712 1713 return result; 1714 } 1715 1716 static void qcow2_close(BlockDriverState *bs) 1717 { 1718 BDRVQcow2State *s = bs->opaque; 1719 qemu_vfree(s->l1_table); 1720 /* else pre-write overlap checks in cache_destroy may crash */ 1721 s->l1_table = NULL; 1722 1723 if (!(s->flags & BDRV_O_INACTIVE)) { 1724 qcow2_inactivate(bs); 1725 } 1726 1727 cache_clean_timer_del(bs); 1728 qcow2_cache_destroy(bs, s->l2_table_cache); 1729 qcow2_cache_destroy(bs, s->refcount_block_cache); 1730 1731 qcrypto_cipher_free(s->cipher); 1732 s->cipher = NULL; 1733 1734 g_free(s->unknown_header_fields); 1735 cleanup_unknown_header_ext(bs); 1736 1737 g_free(s->image_backing_file); 1738 g_free(s->image_backing_format); 1739 1740 g_free(s->cluster_cache); 1741 qemu_vfree(s->cluster_data); 1742 qcow2_refcount_close(bs); 1743 qcow2_free_snapshots(bs); 1744 } 1745 1746 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1747 { 1748 BDRVQcow2State *s = bs->opaque; 1749 int flags = s->flags; 1750 QCryptoCipher *cipher = NULL; 1751 QDict *options; 1752 Error *local_err = NULL; 1753 int ret; 1754 1755 /* 1756 * Backing files are read-only which makes all of their metadata immutable, 1757 * that means we don't have to worry about reopening them here. 1758 */ 1759 1760 cipher = s->cipher; 1761 s->cipher = NULL; 1762 1763 qcow2_close(bs); 1764 1765 bdrv_invalidate_cache(bs->file->bs, &local_err); 1766 if (local_err) { 1767 error_propagate(errp, local_err); 1768 bs->drv = NULL; 1769 return; 1770 } 1771 1772 memset(s, 0, sizeof(BDRVQcow2State)); 1773 options = qdict_clone_shallow(bs->options); 1774 1775 flags &= ~BDRV_O_INACTIVE; 1776 ret = qcow2_open(bs, options, flags, &local_err); 1777 QDECREF(options); 1778 if (local_err) { 1779 error_propagate(errp, local_err); 1780 error_prepend(errp, "Could not reopen qcow2 layer: "); 1781 bs->drv = NULL; 1782 return; 1783 } else if (ret < 0) { 1784 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1785 bs->drv = NULL; 1786 return; 1787 } 1788 1789 s->cipher = cipher; 1790 } 1791 1792 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1793 size_t len, size_t buflen) 1794 { 1795 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1796 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1797 1798 if (buflen < ext_len) { 1799 return -ENOSPC; 1800 } 1801 1802 *ext_backing_fmt = (QCowExtension) { 1803 .magic = cpu_to_be32(magic), 1804 .len = cpu_to_be32(len), 1805 }; 1806 memcpy(buf + sizeof(QCowExtension), s, len); 1807 1808 return ext_len; 1809 } 1810 1811 /* 1812 * Updates the qcow2 header, including the variable length parts of it, i.e. 1813 * the backing file name and all extensions. qcow2 was not designed to allow 1814 * such changes, so if we run out of space (we can only use the first cluster) 1815 * this function may fail. 1816 * 1817 * Returns 0 on success, -errno in error cases. 1818 */ 1819 int qcow2_update_header(BlockDriverState *bs) 1820 { 1821 BDRVQcow2State *s = bs->opaque; 1822 QCowHeader *header; 1823 char *buf; 1824 size_t buflen = s->cluster_size; 1825 int ret; 1826 uint64_t total_size; 1827 uint32_t refcount_table_clusters; 1828 size_t header_length; 1829 Qcow2UnknownHeaderExtension *uext; 1830 1831 buf = qemu_blockalign(bs, buflen); 1832 1833 /* Header structure */ 1834 header = (QCowHeader*) buf; 1835 1836 if (buflen < sizeof(*header)) { 1837 ret = -ENOSPC; 1838 goto fail; 1839 } 1840 1841 header_length = sizeof(*header) + s->unknown_header_fields_size; 1842 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1843 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1844 1845 *header = (QCowHeader) { 1846 /* Version 2 fields */ 1847 .magic = cpu_to_be32(QCOW_MAGIC), 1848 .version = cpu_to_be32(s->qcow_version), 1849 .backing_file_offset = 0, 1850 .backing_file_size = 0, 1851 .cluster_bits = cpu_to_be32(s->cluster_bits), 1852 .size = cpu_to_be64(total_size), 1853 .crypt_method = cpu_to_be32(s->crypt_method_header), 1854 .l1_size = cpu_to_be32(s->l1_size), 1855 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1856 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1857 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1858 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1859 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1860 1861 /* Version 3 fields */ 1862 .incompatible_features = cpu_to_be64(s->incompatible_features), 1863 .compatible_features = cpu_to_be64(s->compatible_features), 1864 .autoclear_features = cpu_to_be64(s->autoclear_features), 1865 .refcount_order = cpu_to_be32(s->refcount_order), 1866 .header_length = cpu_to_be32(header_length), 1867 }; 1868 1869 /* For older versions, write a shorter header */ 1870 switch (s->qcow_version) { 1871 case 2: 1872 ret = offsetof(QCowHeader, incompatible_features); 1873 break; 1874 case 3: 1875 ret = sizeof(*header); 1876 break; 1877 default: 1878 ret = -EINVAL; 1879 goto fail; 1880 } 1881 1882 buf += ret; 1883 buflen -= ret; 1884 memset(buf, 0, buflen); 1885 1886 /* Preserve any unknown field in the header */ 1887 if (s->unknown_header_fields_size) { 1888 if (buflen < s->unknown_header_fields_size) { 1889 ret = -ENOSPC; 1890 goto fail; 1891 } 1892 1893 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1894 buf += s->unknown_header_fields_size; 1895 buflen -= s->unknown_header_fields_size; 1896 } 1897 1898 /* Backing file format header extension */ 1899 if (s->image_backing_format) { 1900 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1901 s->image_backing_format, 1902 strlen(s->image_backing_format), 1903 buflen); 1904 if (ret < 0) { 1905 goto fail; 1906 } 1907 1908 buf += ret; 1909 buflen -= ret; 1910 } 1911 1912 /* Feature table */ 1913 if (s->qcow_version >= 3) { 1914 Qcow2Feature features[] = { 1915 { 1916 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1917 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1918 .name = "dirty bit", 1919 }, 1920 { 1921 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1922 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1923 .name = "corrupt bit", 1924 }, 1925 { 1926 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1927 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1928 .name = "lazy refcounts", 1929 }, 1930 }; 1931 1932 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1933 features, sizeof(features), buflen); 1934 if (ret < 0) { 1935 goto fail; 1936 } 1937 buf += ret; 1938 buflen -= ret; 1939 } 1940 1941 /* Keep unknown header extensions */ 1942 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1943 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1944 if (ret < 0) { 1945 goto fail; 1946 } 1947 1948 buf += ret; 1949 buflen -= ret; 1950 } 1951 1952 /* End of header extensions */ 1953 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1954 if (ret < 0) { 1955 goto fail; 1956 } 1957 1958 buf += ret; 1959 buflen -= ret; 1960 1961 /* Backing file name */ 1962 if (s->image_backing_file) { 1963 size_t backing_file_len = strlen(s->image_backing_file); 1964 1965 if (buflen < backing_file_len) { 1966 ret = -ENOSPC; 1967 goto fail; 1968 } 1969 1970 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1971 strncpy(buf, s->image_backing_file, buflen); 1972 1973 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1974 header->backing_file_size = cpu_to_be32(backing_file_len); 1975 } 1976 1977 /* Write the new header */ 1978 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size); 1979 if (ret < 0) { 1980 goto fail; 1981 } 1982 1983 ret = 0; 1984 fail: 1985 qemu_vfree(header); 1986 return ret; 1987 } 1988 1989 static int qcow2_change_backing_file(BlockDriverState *bs, 1990 const char *backing_file, const char *backing_fmt) 1991 { 1992 BDRVQcow2State *s = bs->opaque; 1993 1994 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1995 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1996 1997 g_free(s->image_backing_file); 1998 g_free(s->image_backing_format); 1999 2000 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2001 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2002 2003 return qcow2_update_header(bs); 2004 } 2005 2006 static int preallocate(BlockDriverState *bs) 2007 { 2008 uint64_t nb_sectors; 2009 uint64_t offset; 2010 uint64_t host_offset = 0; 2011 int num; 2012 int ret; 2013 QCowL2Meta *meta; 2014 2015 nb_sectors = bdrv_nb_sectors(bs); 2016 offset = 0; 2017 2018 while (nb_sectors) { 2019 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 2020 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 2021 &host_offset, &meta); 2022 if (ret < 0) { 2023 return ret; 2024 } 2025 2026 while (meta) { 2027 QCowL2Meta *next = meta->next; 2028 2029 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2030 if (ret < 0) { 2031 qcow2_free_any_clusters(bs, meta->alloc_offset, 2032 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2033 return ret; 2034 } 2035 2036 /* There are no dependent requests, but we need to remove our 2037 * request from the list of in-flight requests */ 2038 QLIST_REMOVE(meta, next_in_flight); 2039 2040 g_free(meta); 2041 meta = next; 2042 } 2043 2044 /* TODO Preallocate data if requested */ 2045 2046 nb_sectors -= num; 2047 offset += num << BDRV_SECTOR_BITS; 2048 } 2049 2050 /* 2051 * It is expected that the image file is large enough to actually contain 2052 * all of the allocated clusters (otherwise we get failing reads after 2053 * EOF). Extend the image to the last allocated sector. 2054 */ 2055 if (host_offset != 0) { 2056 uint8_t buf[BDRV_SECTOR_SIZE]; 2057 memset(buf, 0, BDRV_SECTOR_SIZE); 2058 ret = bdrv_write(bs->file->bs, 2059 (host_offset >> BDRV_SECTOR_BITS) + num - 1, 2060 buf, 1); 2061 if (ret < 0) { 2062 return ret; 2063 } 2064 } 2065 2066 return 0; 2067 } 2068 2069 static int qcow2_create2(const char *filename, int64_t total_size, 2070 const char *backing_file, const char *backing_format, 2071 int flags, size_t cluster_size, PreallocMode prealloc, 2072 QemuOpts *opts, int version, int refcount_order, 2073 Error **errp) 2074 { 2075 int cluster_bits; 2076 QDict *options; 2077 2078 /* Calculate cluster_bits */ 2079 cluster_bits = ctz32(cluster_size); 2080 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2081 (1 << cluster_bits) != cluster_size) 2082 { 2083 error_setg(errp, "Cluster size must be a power of two between %d and " 2084 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2085 return -EINVAL; 2086 } 2087 2088 /* 2089 * Open the image file and write a minimal qcow2 header. 2090 * 2091 * We keep things simple and start with a zero-sized image. We also 2092 * do without refcount blocks or a L1 table for now. We'll fix the 2093 * inconsistency later. 2094 * 2095 * We do need a refcount table because growing the refcount table means 2096 * allocating two new refcount blocks - the seconds of which would be at 2097 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2098 * size for any qcow2 image. 2099 */ 2100 BlockDriverState* bs; 2101 QCowHeader *header; 2102 uint64_t* refcount_table; 2103 Error *local_err = NULL; 2104 int ret; 2105 2106 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2107 /* Note: The following calculation does not need to be exact; if it is a 2108 * bit off, either some bytes will be "leaked" (which is fine) or we 2109 * will need to increase the file size by some bytes (which is fine, 2110 * too, as long as the bulk is allocated here). Therefore, using 2111 * floating point arithmetic is fine. */ 2112 int64_t meta_size = 0; 2113 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2114 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2115 int refblock_bits, refblock_size; 2116 /* refcount entry size in bytes */ 2117 double rces = (1 << refcount_order) / 8.; 2118 2119 /* see qcow2_open() */ 2120 refblock_bits = cluster_bits - (refcount_order - 3); 2121 refblock_size = 1 << refblock_bits; 2122 2123 /* header: 1 cluster */ 2124 meta_size += cluster_size; 2125 2126 /* total size of L2 tables */ 2127 nl2e = aligned_total_size / cluster_size; 2128 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2129 meta_size += nl2e * sizeof(uint64_t); 2130 2131 /* total size of L1 tables */ 2132 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2133 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2134 meta_size += nl1e * sizeof(uint64_t); 2135 2136 /* total size of refcount blocks 2137 * 2138 * note: every host cluster is reference-counted, including metadata 2139 * (even refcount blocks are recursively included). 2140 * Let: 2141 * a = total_size (this is the guest disk size) 2142 * m = meta size not including refcount blocks and refcount tables 2143 * c = cluster size 2144 * y1 = number of refcount blocks entries 2145 * y2 = meta size including everything 2146 * rces = refcount entry size in bytes 2147 * then, 2148 * y1 = (y2 + a)/c 2149 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2150 * we can get y1: 2151 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2152 */ 2153 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2154 / (cluster_size - rces - rces * sizeof(uint64_t) 2155 / cluster_size); 2156 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2157 2158 /* total size of refcount tables */ 2159 nreftablee = nrefblocke / refblock_size; 2160 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2161 meta_size += nreftablee * sizeof(uint64_t); 2162 2163 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2164 aligned_total_size + meta_size, &error_abort); 2165 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2166 &error_abort); 2167 } 2168 2169 ret = bdrv_create_file(filename, opts, &local_err); 2170 if (ret < 0) { 2171 error_propagate(errp, local_err); 2172 return ret; 2173 } 2174 2175 bs = NULL; 2176 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 2177 &local_err); 2178 if (ret < 0) { 2179 error_propagate(errp, local_err); 2180 return ret; 2181 } 2182 2183 /* Write the header */ 2184 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2185 header = g_malloc0(cluster_size); 2186 *header = (QCowHeader) { 2187 .magic = cpu_to_be32(QCOW_MAGIC), 2188 .version = cpu_to_be32(version), 2189 .cluster_bits = cpu_to_be32(cluster_bits), 2190 .size = cpu_to_be64(0), 2191 .l1_table_offset = cpu_to_be64(0), 2192 .l1_size = cpu_to_be32(0), 2193 .refcount_table_offset = cpu_to_be64(cluster_size), 2194 .refcount_table_clusters = cpu_to_be32(1), 2195 .refcount_order = cpu_to_be32(refcount_order), 2196 .header_length = cpu_to_be32(sizeof(*header)), 2197 }; 2198 2199 if (flags & BLOCK_FLAG_ENCRYPT) { 2200 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2201 } else { 2202 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2203 } 2204 2205 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2206 header->compatible_features |= 2207 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2208 } 2209 2210 ret = bdrv_pwrite(bs, 0, header, cluster_size); 2211 g_free(header); 2212 if (ret < 0) { 2213 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2214 goto out; 2215 } 2216 2217 /* Write a refcount table with one refcount block */ 2218 refcount_table = g_malloc0(2 * cluster_size); 2219 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2220 ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size); 2221 g_free(refcount_table); 2222 2223 if (ret < 0) { 2224 error_setg_errno(errp, -ret, "Could not write refcount table"); 2225 goto out; 2226 } 2227 2228 bdrv_unref(bs); 2229 bs = NULL; 2230 2231 /* 2232 * And now open the image and make it consistent first (i.e. increase the 2233 * refcount of the cluster that is occupied by the header and the refcount 2234 * table) 2235 */ 2236 options = qdict_new(); 2237 qdict_put(options, "driver", qstring_from_str("qcow2")); 2238 ret = bdrv_open(&bs, filename, NULL, options, 2239 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, 2240 &local_err); 2241 if (ret < 0) { 2242 error_propagate(errp, local_err); 2243 goto out; 2244 } 2245 2246 ret = qcow2_alloc_clusters(bs, 3 * cluster_size); 2247 if (ret < 0) { 2248 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2249 "header and refcount table"); 2250 goto out; 2251 2252 } else if (ret != 0) { 2253 error_report("Huh, first cluster in empty image is already in use?"); 2254 abort(); 2255 } 2256 2257 /* Create a full header (including things like feature table) */ 2258 ret = qcow2_update_header(bs); 2259 if (ret < 0) { 2260 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2261 goto out; 2262 } 2263 2264 /* Okay, now that we have a valid image, let's give it the right size */ 2265 ret = bdrv_truncate(bs, total_size); 2266 if (ret < 0) { 2267 error_setg_errno(errp, -ret, "Could not resize image"); 2268 goto out; 2269 } 2270 2271 /* Want a backing file? There you go.*/ 2272 if (backing_file) { 2273 ret = bdrv_change_backing_file(bs, backing_file, backing_format); 2274 if (ret < 0) { 2275 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2276 "with format '%s'", backing_file, backing_format); 2277 goto out; 2278 } 2279 } 2280 2281 /* And if we're supposed to preallocate metadata, do that now */ 2282 if (prealloc != PREALLOC_MODE_OFF) { 2283 BDRVQcow2State *s = bs->opaque; 2284 qemu_co_mutex_lock(&s->lock); 2285 ret = preallocate(bs); 2286 qemu_co_mutex_unlock(&s->lock); 2287 if (ret < 0) { 2288 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2289 goto out; 2290 } 2291 } 2292 2293 bdrv_unref(bs); 2294 bs = NULL; 2295 2296 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2297 options = qdict_new(); 2298 qdict_put(options, "driver", qstring_from_str("qcow2")); 2299 ret = bdrv_open(&bs, filename, NULL, options, 2300 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, 2301 &local_err); 2302 if (local_err) { 2303 error_propagate(errp, local_err); 2304 goto out; 2305 } 2306 2307 ret = 0; 2308 out: 2309 if (bs) { 2310 bdrv_unref(bs); 2311 } 2312 return ret; 2313 } 2314 2315 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2316 { 2317 char *backing_file = NULL; 2318 char *backing_fmt = NULL; 2319 char *buf = NULL; 2320 uint64_t size = 0; 2321 int flags = 0; 2322 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2323 PreallocMode prealloc; 2324 int version = 3; 2325 uint64_t refcount_bits = 16; 2326 int refcount_order; 2327 Error *local_err = NULL; 2328 int ret; 2329 2330 /* Read out options */ 2331 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2332 BDRV_SECTOR_SIZE); 2333 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2334 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2335 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2336 flags |= BLOCK_FLAG_ENCRYPT; 2337 } 2338 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2339 DEFAULT_CLUSTER_SIZE); 2340 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2341 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2342 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2343 &local_err); 2344 if (local_err) { 2345 error_propagate(errp, local_err); 2346 ret = -EINVAL; 2347 goto finish; 2348 } 2349 g_free(buf); 2350 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2351 if (!buf) { 2352 /* keep the default */ 2353 } else if (!strcmp(buf, "0.10")) { 2354 version = 2; 2355 } else if (!strcmp(buf, "1.1")) { 2356 version = 3; 2357 } else { 2358 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2359 ret = -EINVAL; 2360 goto finish; 2361 } 2362 2363 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2364 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2365 } 2366 2367 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2368 error_setg(errp, "Backing file and preallocation cannot be used at " 2369 "the same time"); 2370 ret = -EINVAL; 2371 goto finish; 2372 } 2373 2374 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2375 error_setg(errp, "Lazy refcounts only supported with compatibility " 2376 "level 1.1 and above (use compat=1.1 or greater)"); 2377 ret = -EINVAL; 2378 goto finish; 2379 } 2380 2381 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2382 refcount_bits); 2383 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2384 error_setg(errp, "Refcount width must be a power of two and may not " 2385 "exceed 64 bits"); 2386 ret = -EINVAL; 2387 goto finish; 2388 } 2389 2390 if (version < 3 && refcount_bits != 16) { 2391 error_setg(errp, "Different refcount widths than 16 bits require " 2392 "compatibility level 1.1 or above (use compat=1.1 or " 2393 "greater)"); 2394 ret = -EINVAL; 2395 goto finish; 2396 } 2397 2398 refcount_order = ctz32(refcount_bits); 2399 2400 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2401 cluster_size, prealloc, opts, version, refcount_order, 2402 &local_err); 2403 if (local_err) { 2404 error_propagate(errp, local_err); 2405 } 2406 2407 finish: 2408 g_free(backing_file); 2409 g_free(backing_fmt); 2410 g_free(buf); 2411 return ret; 2412 } 2413 2414 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2415 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2416 { 2417 int ret; 2418 BDRVQcow2State *s = bs->opaque; 2419 2420 /* Emulate misaligned zero writes */ 2421 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { 2422 return -ENOTSUP; 2423 } 2424 2425 /* Whatever is left can use real zero clusters */ 2426 qemu_co_mutex_lock(&s->lock); 2427 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2428 nb_sectors); 2429 qemu_co_mutex_unlock(&s->lock); 2430 2431 return ret; 2432 } 2433 2434 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2435 int64_t sector_num, int nb_sectors) 2436 { 2437 int ret; 2438 BDRVQcow2State *s = bs->opaque; 2439 2440 qemu_co_mutex_lock(&s->lock); 2441 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2442 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2443 qemu_co_mutex_unlock(&s->lock); 2444 return ret; 2445 } 2446 2447 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2448 { 2449 BDRVQcow2State *s = bs->opaque; 2450 int64_t new_l1_size; 2451 int ret; 2452 2453 if (offset & 511) { 2454 error_report("The new size must be a multiple of 512"); 2455 return -EINVAL; 2456 } 2457 2458 /* cannot proceed if image has snapshots */ 2459 if (s->nb_snapshots) { 2460 error_report("Can't resize an image which has snapshots"); 2461 return -ENOTSUP; 2462 } 2463 2464 /* shrinking is currently not supported */ 2465 if (offset < bs->total_sectors * 512) { 2466 error_report("qcow2 doesn't support shrinking images yet"); 2467 return -ENOTSUP; 2468 } 2469 2470 new_l1_size = size_to_l1(s, offset); 2471 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2472 if (ret < 0) { 2473 return ret; 2474 } 2475 2476 /* write updated header.size */ 2477 offset = cpu_to_be64(offset); 2478 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), 2479 &offset, sizeof(uint64_t)); 2480 if (ret < 0) { 2481 return ret; 2482 } 2483 2484 s->l1_vm_state_index = new_l1_size; 2485 return 0; 2486 } 2487 2488 /* XXX: put compressed sectors first, then all the cluster aligned 2489 tables to avoid losing bytes in alignment */ 2490 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2491 const uint8_t *buf, int nb_sectors) 2492 { 2493 BDRVQcow2State *s = bs->opaque; 2494 z_stream strm; 2495 int ret, out_len; 2496 uint8_t *out_buf; 2497 uint64_t cluster_offset; 2498 2499 if (nb_sectors == 0) { 2500 /* align end of file to a sector boundary to ease reading with 2501 sector based I/Os */ 2502 cluster_offset = bdrv_getlength(bs->file->bs); 2503 return bdrv_truncate(bs->file->bs, cluster_offset); 2504 } 2505 2506 if (nb_sectors != s->cluster_sectors) { 2507 ret = -EINVAL; 2508 2509 /* Zero-pad last write if image size is not cluster aligned */ 2510 if (sector_num + nb_sectors == bs->total_sectors && 2511 nb_sectors < s->cluster_sectors) { 2512 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2513 memset(pad_buf, 0, s->cluster_size); 2514 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2515 ret = qcow2_write_compressed(bs, sector_num, 2516 pad_buf, s->cluster_sectors); 2517 qemu_vfree(pad_buf); 2518 } 2519 return ret; 2520 } 2521 2522 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2523 2524 /* best compression, small window, no zlib header */ 2525 memset(&strm, 0, sizeof(strm)); 2526 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2527 Z_DEFLATED, -12, 2528 9, Z_DEFAULT_STRATEGY); 2529 if (ret != 0) { 2530 ret = -EINVAL; 2531 goto fail; 2532 } 2533 2534 strm.avail_in = s->cluster_size; 2535 strm.next_in = (uint8_t *)buf; 2536 strm.avail_out = s->cluster_size; 2537 strm.next_out = out_buf; 2538 2539 ret = deflate(&strm, Z_FINISH); 2540 if (ret != Z_STREAM_END && ret != Z_OK) { 2541 deflateEnd(&strm); 2542 ret = -EINVAL; 2543 goto fail; 2544 } 2545 out_len = strm.next_out - out_buf; 2546 2547 deflateEnd(&strm); 2548 2549 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2550 /* could not compress: write normal cluster */ 2551 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2552 if (ret < 0) { 2553 goto fail; 2554 } 2555 } else { 2556 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2557 sector_num << 9, out_len); 2558 if (!cluster_offset) { 2559 ret = -EIO; 2560 goto fail; 2561 } 2562 cluster_offset &= s->cluster_offset_mask; 2563 2564 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2565 if (ret < 0) { 2566 goto fail; 2567 } 2568 2569 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2570 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 2571 if (ret < 0) { 2572 goto fail; 2573 } 2574 } 2575 2576 ret = 0; 2577 fail: 2578 g_free(out_buf); 2579 return ret; 2580 } 2581 2582 static int make_completely_empty(BlockDriverState *bs) 2583 { 2584 BDRVQcow2State *s = bs->opaque; 2585 int ret, l1_clusters; 2586 int64_t offset; 2587 uint64_t *new_reftable = NULL; 2588 uint64_t rt_entry, l1_size2; 2589 struct { 2590 uint64_t l1_offset; 2591 uint64_t reftable_offset; 2592 uint32_t reftable_clusters; 2593 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2594 2595 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2596 if (ret < 0) { 2597 goto fail; 2598 } 2599 2600 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2601 if (ret < 0) { 2602 goto fail; 2603 } 2604 2605 /* Refcounts will be broken utterly */ 2606 ret = qcow2_mark_dirty(bs); 2607 if (ret < 0) { 2608 goto fail; 2609 } 2610 2611 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2612 2613 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2614 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2615 2616 /* After this call, neither the in-memory nor the on-disk refcount 2617 * information accurately describe the actual references */ 2618 2619 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, 2620 l1_clusters * s->cluster_sectors, 0); 2621 if (ret < 0) { 2622 goto fail_broken_refcounts; 2623 } 2624 memset(s->l1_table, 0, l1_size2); 2625 2626 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2627 2628 /* Overwrite enough clusters at the beginning of the sectors to place 2629 * the refcount table, a refcount block and the L1 table in; this may 2630 * overwrite parts of the existing refcount and L1 table, which is not 2631 * an issue because the dirty flag is set, complete data loss is in fact 2632 * desired and partial data loss is consequently fine as well */ 2633 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, 2634 (2 + l1_clusters) * s->cluster_size / 2635 BDRV_SECTOR_SIZE, 0); 2636 /* This call (even if it failed overall) may have overwritten on-disk 2637 * refcount structures; in that case, the in-memory refcount information 2638 * will probably differ from the on-disk information which makes the BDS 2639 * unusable */ 2640 if (ret < 0) { 2641 goto fail_broken_refcounts; 2642 } 2643 2644 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2645 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2646 2647 /* "Create" an empty reftable (one cluster) directly after the image 2648 * header and an empty L1 table three clusters after the image header; 2649 * the cluster between those two will be used as the first refblock */ 2650 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2651 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2652 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2653 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset), 2654 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2655 if (ret < 0) { 2656 goto fail_broken_refcounts; 2657 } 2658 2659 s->l1_table_offset = 3 * s->cluster_size; 2660 2661 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2662 if (!new_reftable) { 2663 ret = -ENOMEM; 2664 goto fail_broken_refcounts; 2665 } 2666 2667 s->refcount_table_offset = s->cluster_size; 2668 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2669 2670 g_free(s->refcount_table); 2671 s->refcount_table = new_reftable; 2672 new_reftable = NULL; 2673 2674 /* Now the in-memory refcount information again corresponds to the on-disk 2675 * information (reftable is empty and no refblocks (the refblock cache is 2676 * empty)); however, this means some clusters (e.g. the image header) are 2677 * referenced, but not refcounted, but the normal qcow2 code assumes that 2678 * the in-memory information is always correct */ 2679 2680 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2681 2682 /* Enter the first refblock into the reftable */ 2683 rt_entry = cpu_to_be64(2 * s->cluster_size); 2684 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size, 2685 &rt_entry, sizeof(rt_entry)); 2686 if (ret < 0) { 2687 goto fail_broken_refcounts; 2688 } 2689 s->refcount_table[0] = 2 * s->cluster_size; 2690 2691 s->free_cluster_index = 0; 2692 assert(3 + l1_clusters <= s->refcount_block_size); 2693 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2694 if (offset < 0) { 2695 ret = offset; 2696 goto fail_broken_refcounts; 2697 } else if (offset > 0) { 2698 error_report("First cluster in emptied image is in use"); 2699 abort(); 2700 } 2701 2702 /* Now finally the in-memory information corresponds to the on-disk 2703 * structures and is correct */ 2704 ret = qcow2_mark_clean(bs); 2705 if (ret < 0) { 2706 goto fail; 2707 } 2708 2709 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2710 if (ret < 0) { 2711 goto fail; 2712 } 2713 2714 return 0; 2715 2716 fail_broken_refcounts: 2717 /* The BDS is unusable at this point. If we wanted to make it usable, we 2718 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2719 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2720 * again. However, because the functions which could have caused this error 2721 * path to be taken are used by those functions as well, it's very likely 2722 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2723 bs->drv = NULL; 2724 2725 fail: 2726 g_free(new_reftable); 2727 return ret; 2728 } 2729 2730 static int qcow2_make_empty(BlockDriverState *bs) 2731 { 2732 BDRVQcow2State *s = bs->opaque; 2733 uint64_t start_sector; 2734 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2735 int l1_clusters, ret = 0; 2736 2737 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2738 2739 if (s->qcow_version >= 3 && !s->snapshots && 2740 3 + l1_clusters <= s->refcount_block_size) { 2741 /* The following function only works for qcow2 v3 images (it requires 2742 * the dirty flag) and only as long as there are no snapshots (because 2743 * it completely empties the image). Furthermore, the L1 table and three 2744 * additional clusters (image header, refcount table, one refcount 2745 * block) have to fit inside one refcount block. */ 2746 return make_completely_empty(bs); 2747 } 2748 2749 /* This fallback code simply discards every active cluster; this is slow, 2750 * but works in all cases */ 2751 for (start_sector = 0; start_sector < bs->total_sectors; 2752 start_sector += sector_step) 2753 { 2754 /* As this function is generally used after committing an external 2755 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2756 * default action for this kind of discard is to pass the discard, 2757 * which will ideally result in an actually smaller image file, as 2758 * is probably desired. */ 2759 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2760 MIN(sector_step, 2761 bs->total_sectors - start_sector), 2762 QCOW2_DISCARD_SNAPSHOT, true); 2763 if (ret < 0) { 2764 break; 2765 } 2766 } 2767 2768 return ret; 2769 } 2770 2771 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2772 { 2773 BDRVQcow2State *s = bs->opaque; 2774 int ret; 2775 2776 qemu_co_mutex_lock(&s->lock); 2777 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2778 if (ret < 0) { 2779 qemu_co_mutex_unlock(&s->lock); 2780 return ret; 2781 } 2782 2783 if (qcow2_need_accurate_refcounts(s)) { 2784 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2785 if (ret < 0) { 2786 qemu_co_mutex_unlock(&s->lock); 2787 return ret; 2788 } 2789 } 2790 qemu_co_mutex_unlock(&s->lock); 2791 2792 return 0; 2793 } 2794 2795 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2796 { 2797 BDRVQcow2State *s = bs->opaque; 2798 bdi->unallocated_blocks_are_zero = true; 2799 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2800 bdi->cluster_size = s->cluster_size; 2801 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2802 return 0; 2803 } 2804 2805 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2806 { 2807 BDRVQcow2State *s = bs->opaque; 2808 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2809 2810 *spec_info = (ImageInfoSpecific){ 2811 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2812 .u.qcow2 = g_new(ImageInfoSpecificQCow2, 1), 2813 }; 2814 if (s->qcow_version == 2) { 2815 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2816 .compat = g_strdup("0.10"), 2817 .refcount_bits = s->refcount_bits, 2818 }; 2819 } else if (s->qcow_version == 3) { 2820 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2821 .compat = g_strdup("1.1"), 2822 .lazy_refcounts = s->compatible_features & 2823 QCOW2_COMPAT_LAZY_REFCOUNTS, 2824 .has_lazy_refcounts = true, 2825 .corrupt = s->incompatible_features & 2826 QCOW2_INCOMPAT_CORRUPT, 2827 .has_corrupt = true, 2828 .refcount_bits = s->refcount_bits, 2829 }; 2830 } else { 2831 /* if this assertion fails, this probably means a new version was 2832 * added without having it covered here */ 2833 assert(false); 2834 } 2835 2836 return spec_info; 2837 } 2838 2839 #if 0 2840 static void dump_refcounts(BlockDriverState *bs) 2841 { 2842 BDRVQcow2State *s = bs->opaque; 2843 int64_t nb_clusters, k, k1, size; 2844 int refcount; 2845 2846 size = bdrv_getlength(bs->file->bs); 2847 nb_clusters = size_to_clusters(s, size); 2848 for(k = 0; k < nb_clusters;) { 2849 k1 = k; 2850 refcount = get_refcount(bs, k); 2851 k++; 2852 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2853 k++; 2854 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2855 k - k1); 2856 } 2857 } 2858 #endif 2859 2860 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2861 int64_t pos) 2862 { 2863 BDRVQcow2State *s = bs->opaque; 2864 int64_t total_sectors = bs->total_sectors; 2865 bool zero_beyond_eof = bs->zero_beyond_eof; 2866 int ret; 2867 2868 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2869 bs->zero_beyond_eof = false; 2870 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2871 bs->zero_beyond_eof = zero_beyond_eof; 2872 2873 /* bdrv_co_do_writev will have increased the total_sectors value to include 2874 * the VM state - the VM state is however not an actual part of the block 2875 * device, therefore, we need to restore the old value. */ 2876 bs->total_sectors = total_sectors; 2877 2878 return ret; 2879 } 2880 2881 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2882 int64_t pos, int size) 2883 { 2884 BDRVQcow2State *s = bs->opaque; 2885 bool zero_beyond_eof = bs->zero_beyond_eof; 2886 int ret; 2887 2888 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2889 bs->zero_beyond_eof = false; 2890 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2891 bs->zero_beyond_eof = zero_beyond_eof; 2892 2893 return ret; 2894 } 2895 2896 /* 2897 * Downgrades an image's version. To achieve this, any incompatible features 2898 * have to be removed. 2899 */ 2900 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2901 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2902 { 2903 BDRVQcow2State *s = bs->opaque; 2904 int current_version = s->qcow_version; 2905 int ret; 2906 2907 if (target_version == current_version) { 2908 return 0; 2909 } else if (target_version > current_version) { 2910 return -EINVAL; 2911 } else if (target_version != 2) { 2912 return -EINVAL; 2913 } 2914 2915 if (s->refcount_order != 4) { 2916 error_report("compat=0.10 requires refcount_bits=16"); 2917 return -ENOTSUP; 2918 } 2919 2920 /* clear incompatible features */ 2921 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2922 ret = qcow2_mark_clean(bs); 2923 if (ret < 0) { 2924 return ret; 2925 } 2926 } 2927 2928 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2929 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2930 * best thing to do anyway */ 2931 2932 if (s->incompatible_features) { 2933 return -ENOTSUP; 2934 } 2935 2936 /* since we can ignore compatible features, we can set them to 0 as well */ 2937 s->compatible_features = 0; 2938 /* if lazy refcounts have been used, they have already been fixed through 2939 * clearing the dirty flag */ 2940 2941 /* clearing autoclear features is trivial */ 2942 s->autoclear_features = 0; 2943 2944 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 2945 if (ret < 0) { 2946 return ret; 2947 } 2948 2949 s->qcow_version = target_version; 2950 ret = qcow2_update_header(bs); 2951 if (ret < 0) { 2952 s->qcow_version = current_version; 2953 return ret; 2954 } 2955 return 0; 2956 } 2957 2958 typedef enum Qcow2AmendOperation { 2959 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 2960 * statically initialized to so that the helper CB can discern the first 2961 * invocation from an operation change */ 2962 QCOW2_NO_OPERATION = 0, 2963 2964 QCOW2_CHANGING_REFCOUNT_ORDER, 2965 QCOW2_DOWNGRADING, 2966 } Qcow2AmendOperation; 2967 2968 typedef struct Qcow2AmendHelperCBInfo { 2969 /* The code coordinating the amend operations should only modify 2970 * these four fields; the rest will be managed by the CB */ 2971 BlockDriverAmendStatusCB *original_status_cb; 2972 void *original_cb_opaque; 2973 2974 Qcow2AmendOperation current_operation; 2975 2976 /* Total number of operations to perform (only set once) */ 2977 int total_operations; 2978 2979 /* The following fields are managed by the CB */ 2980 2981 /* Number of operations completed */ 2982 int operations_completed; 2983 2984 /* Cumulative offset of all completed operations */ 2985 int64_t offset_completed; 2986 2987 Qcow2AmendOperation last_operation; 2988 int64_t last_work_size; 2989 } Qcow2AmendHelperCBInfo; 2990 2991 static void qcow2_amend_helper_cb(BlockDriverState *bs, 2992 int64_t operation_offset, 2993 int64_t operation_work_size, void *opaque) 2994 { 2995 Qcow2AmendHelperCBInfo *info = opaque; 2996 int64_t current_work_size; 2997 int64_t projected_work_size; 2998 2999 if (info->current_operation != info->last_operation) { 3000 if (info->last_operation != QCOW2_NO_OPERATION) { 3001 info->offset_completed += info->last_work_size; 3002 info->operations_completed++; 3003 } 3004 3005 info->last_operation = info->current_operation; 3006 } 3007 3008 assert(info->total_operations > 0); 3009 assert(info->operations_completed < info->total_operations); 3010 3011 info->last_work_size = operation_work_size; 3012 3013 current_work_size = info->offset_completed + operation_work_size; 3014 3015 /* current_work_size is the total work size for (operations_completed + 1) 3016 * operations (which includes this one), so multiply it by the number of 3017 * operations not covered and divide it by the number of operations 3018 * covered to get a projection for the operations not covered */ 3019 projected_work_size = current_work_size * (info->total_operations - 3020 info->operations_completed - 1) 3021 / (info->operations_completed + 1); 3022 3023 info->original_status_cb(bs, info->offset_completed + operation_offset, 3024 current_work_size + projected_work_size, 3025 info->original_cb_opaque); 3026 } 3027 3028 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3029 BlockDriverAmendStatusCB *status_cb, 3030 void *cb_opaque) 3031 { 3032 BDRVQcow2State *s = bs->opaque; 3033 int old_version = s->qcow_version, new_version = old_version; 3034 uint64_t new_size = 0; 3035 const char *backing_file = NULL, *backing_format = NULL; 3036 bool lazy_refcounts = s->use_lazy_refcounts; 3037 const char *compat = NULL; 3038 uint64_t cluster_size = s->cluster_size; 3039 bool encrypt; 3040 int refcount_bits = s->refcount_bits; 3041 int ret; 3042 QemuOptDesc *desc = opts->list->desc; 3043 Qcow2AmendHelperCBInfo helper_cb_info; 3044 3045 while (desc && desc->name) { 3046 if (!qemu_opt_find(opts, desc->name)) { 3047 /* only change explicitly defined options */ 3048 desc++; 3049 continue; 3050 } 3051 3052 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3053 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3054 if (!compat) { 3055 /* preserve default */ 3056 } else if (!strcmp(compat, "0.10")) { 3057 new_version = 2; 3058 } else if (!strcmp(compat, "1.1")) { 3059 new_version = 3; 3060 } else { 3061 error_report("Unknown compatibility level %s", compat); 3062 return -EINVAL; 3063 } 3064 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3065 error_report("Cannot change preallocation mode"); 3066 return -ENOTSUP; 3067 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3068 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3069 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3070 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3071 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3072 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3073 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3074 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3075 !!s->cipher); 3076 3077 if (encrypt != !!s->cipher) { 3078 error_report("Changing the encryption flag is not supported"); 3079 return -ENOTSUP; 3080 } 3081 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3082 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3083 cluster_size); 3084 if (cluster_size != s->cluster_size) { 3085 error_report("Changing the cluster size is not supported"); 3086 return -ENOTSUP; 3087 } 3088 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3089 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3090 lazy_refcounts); 3091 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3092 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3093 refcount_bits); 3094 3095 if (refcount_bits <= 0 || refcount_bits > 64 || 3096 !is_power_of_2(refcount_bits)) 3097 { 3098 error_report("Refcount width must be a power of two and may " 3099 "not exceed 64 bits"); 3100 return -EINVAL; 3101 } 3102 } else { 3103 /* if this point is reached, this probably means a new option was 3104 * added without having it covered here */ 3105 abort(); 3106 } 3107 3108 desc++; 3109 } 3110 3111 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3112 .original_status_cb = status_cb, 3113 .original_cb_opaque = cb_opaque, 3114 .total_operations = (new_version < old_version) 3115 + (s->refcount_bits != refcount_bits) 3116 }; 3117 3118 /* Upgrade first (some features may require compat=1.1) */ 3119 if (new_version > old_version) { 3120 s->qcow_version = new_version; 3121 ret = qcow2_update_header(bs); 3122 if (ret < 0) { 3123 s->qcow_version = old_version; 3124 return ret; 3125 } 3126 } 3127 3128 if (s->refcount_bits != refcount_bits) { 3129 int refcount_order = ctz32(refcount_bits); 3130 Error *local_error = NULL; 3131 3132 if (new_version < 3 && refcount_bits != 16) { 3133 error_report("Different refcount widths than 16 bits require " 3134 "compatibility level 1.1 or above (use compat=1.1 or " 3135 "greater)"); 3136 return -EINVAL; 3137 } 3138 3139 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3140 ret = qcow2_change_refcount_order(bs, refcount_order, 3141 &qcow2_amend_helper_cb, 3142 &helper_cb_info, &local_error); 3143 if (ret < 0) { 3144 error_report_err(local_error); 3145 return ret; 3146 } 3147 } 3148 3149 if (backing_file || backing_format) { 3150 ret = qcow2_change_backing_file(bs, 3151 backing_file ?: s->image_backing_file, 3152 backing_format ?: s->image_backing_format); 3153 if (ret < 0) { 3154 return ret; 3155 } 3156 } 3157 3158 if (s->use_lazy_refcounts != lazy_refcounts) { 3159 if (lazy_refcounts) { 3160 if (new_version < 3) { 3161 error_report("Lazy refcounts only supported with compatibility " 3162 "level 1.1 and above (use compat=1.1 or greater)"); 3163 return -EINVAL; 3164 } 3165 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3166 ret = qcow2_update_header(bs); 3167 if (ret < 0) { 3168 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3169 return ret; 3170 } 3171 s->use_lazy_refcounts = true; 3172 } else { 3173 /* make image clean first */ 3174 ret = qcow2_mark_clean(bs); 3175 if (ret < 0) { 3176 return ret; 3177 } 3178 /* now disallow lazy refcounts */ 3179 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3180 ret = qcow2_update_header(bs); 3181 if (ret < 0) { 3182 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3183 return ret; 3184 } 3185 s->use_lazy_refcounts = false; 3186 } 3187 } 3188 3189 if (new_size) { 3190 ret = bdrv_truncate(bs, new_size); 3191 if (ret < 0) { 3192 return ret; 3193 } 3194 } 3195 3196 /* Downgrade last (so unsupported features can be removed before) */ 3197 if (new_version < old_version) { 3198 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3199 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3200 &helper_cb_info); 3201 if (ret < 0) { 3202 return ret; 3203 } 3204 } 3205 3206 return 0; 3207 } 3208 3209 /* 3210 * If offset or size are negative, respectively, they will not be included in 3211 * the BLOCK_IMAGE_CORRUPTED event emitted. 3212 * fatal will be ignored for read-only BDS; corruptions found there will always 3213 * be considered non-fatal. 3214 */ 3215 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3216 int64_t size, const char *message_format, ...) 3217 { 3218 BDRVQcow2State *s = bs->opaque; 3219 const char *node_name; 3220 char *message; 3221 va_list ap; 3222 3223 fatal = fatal && !bs->read_only; 3224 3225 if (s->signaled_corruption && 3226 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3227 { 3228 return; 3229 } 3230 3231 va_start(ap, message_format); 3232 message = g_strdup_vprintf(message_format, ap); 3233 va_end(ap); 3234 3235 if (fatal) { 3236 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3237 "corruption events will be suppressed\n", message); 3238 } else { 3239 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3240 "corruption events will be suppressed\n", message); 3241 } 3242 3243 node_name = bdrv_get_node_name(bs); 3244 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3245 *node_name != '\0', node_name, 3246 message, offset >= 0, offset, 3247 size >= 0, size, 3248 fatal, &error_abort); 3249 g_free(message); 3250 3251 if (fatal) { 3252 qcow2_mark_corrupt(bs); 3253 bs->drv = NULL; /* make BDS unusable */ 3254 } 3255 3256 s->signaled_corruption = true; 3257 } 3258 3259 static QemuOptsList qcow2_create_opts = { 3260 .name = "qcow2-create-opts", 3261 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3262 .desc = { 3263 { 3264 .name = BLOCK_OPT_SIZE, 3265 .type = QEMU_OPT_SIZE, 3266 .help = "Virtual disk size" 3267 }, 3268 { 3269 .name = BLOCK_OPT_COMPAT_LEVEL, 3270 .type = QEMU_OPT_STRING, 3271 .help = "Compatibility level (0.10 or 1.1)" 3272 }, 3273 { 3274 .name = BLOCK_OPT_BACKING_FILE, 3275 .type = QEMU_OPT_STRING, 3276 .help = "File name of a base image" 3277 }, 3278 { 3279 .name = BLOCK_OPT_BACKING_FMT, 3280 .type = QEMU_OPT_STRING, 3281 .help = "Image format of the base image" 3282 }, 3283 { 3284 .name = BLOCK_OPT_ENCRYPT, 3285 .type = QEMU_OPT_BOOL, 3286 .help = "Encrypt the image", 3287 .def_value_str = "off" 3288 }, 3289 { 3290 .name = BLOCK_OPT_CLUSTER_SIZE, 3291 .type = QEMU_OPT_SIZE, 3292 .help = "qcow2 cluster size", 3293 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3294 }, 3295 { 3296 .name = BLOCK_OPT_PREALLOC, 3297 .type = QEMU_OPT_STRING, 3298 .help = "Preallocation mode (allowed values: off, metadata, " 3299 "falloc, full)" 3300 }, 3301 { 3302 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3303 .type = QEMU_OPT_BOOL, 3304 .help = "Postpone refcount updates", 3305 .def_value_str = "off" 3306 }, 3307 { 3308 .name = BLOCK_OPT_REFCOUNT_BITS, 3309 .type = QEMU_OPT_NUMBER, 3310 .help = "Width of a reference count entry in bits", 3311 .def_value_str = "16" 3312 }, 3313 { /* end of list */ } 3314 } 3315 }; 3316 3317 BlockDriver bdrv_qcow2 = { 3318 .format_name = "qcow2", 3319 .instance_size = sizeof(BDRVQcow2State), 3320 .bdrv_probe = qcow2_probe, 3321 .bdrv_open = qcow2_open, 3322 .bdrv_close = qcow2_close, 3323 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3324 .bdrv_reopen_commit = qcow2_reopen_commit, 3325 .bdrv_reopen_abort = qcow2_reopen_abort, 3326 .bdrv_join_options = qcow2_join_options, 3327 .bdrv_create = qcow2_create, 3328 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3329 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3330 .bdrv_set_key = qcow2_set_key, 3331 3332 .bdrv_co_readv = qcow2_co_readv, 3333 .bdrv_co_writev = qcow2_co_writev, 3334 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3335 3336 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3337 .bdrv_co_discard = qcow2_co_discard, 3338 .bdrv_truncate = qcow2_truncate, 3339 .bdrv_write_compressed = qcow2_write_compressed, 3340 .bdrv_make_empty = qcow2_make_empty, 3341 3342 .bdrv_snapshot_create = qcow2_snapshot_create, 3343 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3344 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3345 .bdrv_snapshot_list = qcow2_snapshot_list, 3346 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3347 .bdrv_get_info = qcow2_get_info, 3348 .bdrv_get_specific_info = qcow2_get_specific_info, 3349 3350 .bdrv_save_vmstate = qcow2_save_vmstate, 3351 .bdrv_load_vmstate = qcow2_load_vmstate, 3352 3353 .supports_backing = true, 3354 .bdrv_change_backing_file = qcow2_change_backing_file, 3355 3356 .bdrv_refresh_limits = qcow2_refresh_limits, 3357 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3358 .bdrv_inactivate = qcow2_inactivate, 3359 3360 .create_opts = &qcow2_create_opts, 3361 .bdrv_check = qcow2_check, 3362 .bdrv_amend_options = qcow2_amend_options, 3363 3364 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3365 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3366 }; 3367 3368 static void bdrv_qcow2_init(void) 3369 { 3370 bdrv_register(&bdrv_qcow2); 3371 } 3372 3373 block_init(bdrv_qcow2_init); 3374