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) 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 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1353 } 1354 if (ret == QCOW2_CLUSTER_ZERO) { 1355 status |= BDRV_BLOCK_ZERO; 1356 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1357 status |= BDRV_BLOCK_DATA; 1358 } 1359 return status; 1360 } 1361 1362 /* handle reading after the end of the backing file */ 1363 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1364 int64_t sector_num, int nb_sectors) 1365 { 1366 int n1; 1367 if ((sector_num + nb_sectors) <= bs->total_sectors) 1368 return nb_sectors; 1369 if (sector_num >= bs->total_sectors) 1370 n1 = 0; 1371 else 1372 n1 = bs->total_sectors - sector_num; 1373 1374 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1)); 1375 1376 return n1; 1377 } 1378 1379 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num, 1380 int remaining_sectors, QEMUIOVector *qiov) 1381 { 1382 BDRVQcow2State *s = bs->opaque; 1383 int index_in_cluster, n1; 1384 int ret; 1385 int cur_nr_sectors; /* number of sectors in current iteration */ 1386 uint64_t cluster_offset = 0; 1387 uint64_t bytes_done = 0; 1388 QEMUIOVector hd_qiov; 1389 uint8_t *cluster_data = NULL; 1390 1391 qemu_iovec_init(&hd_qiov, qiov->niov); 1392 1393 qemu_co_mutex_lock(&s->lock); 1394 1395 while (remaining_sectors != 0) { 1396 1397 /* prepare next request */ 1398 cur_nr_sectors = remaining_sectors; 1399 if (s->cipher) { 1400 cur_nr_sectors = MIN(cur_nr_sectors, 1401 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1402 } 1403 1404 ret = qcow2_get_cluster_offset(bs, sector_num << 9, 1405 &cur_nr_sectors, &cluster_offset); 1406 if (ret < 0) { 1407 goto fail; 1408 } 1409 1410 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1411 1412 qemu_iovec_reset(&hd_qiov); 1413 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1414 cur_nr_sectors * 512); 1415 1416 switch (ret) { 1417 case QCOW2_CLUSTER_UNALLOCATED: 1418 1419 if (bs->backing) { 1420 /* read from the base image */ 1421 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1422 sector_num, cur_nr_sectors); 1423 if (n1 > 0) { 1424 QEMUIOVector local_qiov; 1425 1426 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1427 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, 1428 n1 * BDRV_SECTOR_SIZE); 1429 1430 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1431 qemu_co_mutex_unlock(&s->lock); 1432 ret = bdrv_co_readv(bs->backing->bs, sector_num, 1433 n1, &local_qiov); 1434 qemu_co_mutex_lock(&s->lock); 1435 1436 qemu_iovec_destroy(&local_qiov); 1437 1438 if (ret < 0) { 1439 goto fail; 1440 } 1441 } 1442 } else { 1443 /* Note: in this case, no need to wait */ 1444 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1445 } 1446 break; 1447 1448 case QCOW2_CLUSTER_ZERO: 1449 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors); 1450 break; 1451 1452 case QCOW2_CLUSTER_COMPRESSED: 1453 /* add AIO support for compressed blocks ? */ 1454 ret = qcow2_decompress_cluster(bs, cluster_offset); 1455 if (ret < 0) { 1456 goto fail; 1457 } 1458 1459 qemu_iovec_from_buf(&hd_qiov, 0, 1460 s->cluster_cache + index_in_cluster * 512, 1461 512 * cur_nr_sectors); 1462 break; 1463 1464 case QCOW2_CLUSTER_NORMAL: 1465 if ((cluster_offset & 511) != 0) { 1466 ret = -EIO; 1467 goto fail; 1468 } 1469 1470 if (bs->encrypted) { 1471 assert(s->cipher); 1472 1473 /* 1474 * For encrypted images, read everything into a temporary 1475 * contiguous buffer on which the AES functions can work. 1476 */ 1477 if (!cluster_data) { 1478 cluster_data = 1479 qemu_try_blockalign(bs->file->bs, 1480 QCOW_MAX_CRYPT_CLUSTERS 1481 * s->cluster_size); 1482 if (cluster_data == NULL) { 1483 ret = -ENOMEM; 1484 goto fail; 1485 } 1486 } 1487 1488 assert(cur_nr_sectors <= 1489 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors); 1490 qemu_iovec_reset(&hd_qiov); 1491 qemu_iovec_add(&hd_qiov, cluster_data, 1492 512 * cur_nr_sectors); 1493 } 1494 1495 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1496 qemu_co_mutex_unlock(&s->lock); 1497 ret = bdrv_co_readv(bs->file->bs, 1498 (cluster_offset >> 9) + index_in_cluster, 1499 cur_nr_sectors, &hd_qiov); 1500 qemu_co_mutex_lock(&s->lock); 1501 if (ret < 0) { 1502 goto fail; 1503 } 1504 if (bs->encrypted) { 1505 assert(s->cipher); 1506 Error *err = NULL; 1507 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1508 cluster_data, cur_nr_sectors, false, 1509 &err) < 0) { 1510 error_free(err); 1511 ret = -EIO; 1512 goto fail; 1513 } 1514 qemu_iovec_from_buf(qiov, bytes_done, 1515 cluster_data, 512 * cur_nr_sectors); 1516 } 1517 break; 1518 1519 default: 1520 g_assert_not_reached(); 1521 ret = -EIO; 1522 goto fail; 1523 } 1524 1525 remaining_sectors -= cur_nr_sectors; 1526 sector_num += cur_nr_sectors; 1527 bytes_done += cur_nr_sectors * 512; 1528 } 1529 ret = 0; 1530 1531 fail: 1532 qemu_co_mutex_unlock(&s->lock); 1533 1534 qemu_iovec_destroy(&hd_qiov); 1535 qemu_vfree(cluster_data); 1536 1537 return ret; 1538 } 1539 1540 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, 1541 int64_t sector_num, 1542 int remaining_sectors, 1543 QEMUIOVector *qiov) 1544 { 1545 BDRVQcow2State *s = bs->opaque; 1546 int index_in_cluster; 1547 int ret; 1548 int cur_nr_sectors; /* number of sectors in current iteration */ 1549 uint64_t cluster_offset; 1550 QEMUIOVector hd_qiov; 1551 uint64_t bytes_done = 0; 1552 uint8_t *cluster_data = NULL; 1553 QCowL2Meta *l2meta = NULL; 1554 1555 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num, 1556 remaining_sectors); 1557 1558 qemu_iovec_init(&hd_qiov, qiov->niov); 1559 1560 s->cluster_cache_offset = -1; /* disable compressed cache */ 1561 1562 qemu_co_mutex_lock(&s->lock); 1563 1564 while (remaining_sectors != 0) { 1565 1566 l2meta = NULL; 1567 1568 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1569 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1570 cur_nr_sectors = remaining_sectors; 1571 if (bs->encrypted && 1572 cur_nr_sectors > 1573 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) { 1574 cur_nr_sectors = 1575 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster; 1576 } 1577 1578 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9, 1579 &cur_nr_sectors, &cluster_offset, &l2meta); 1580 if (ret < 0) { 1581 goto fail; 1582 } 1583 1584 assert((cluster_offset & 511) == 0); 1585 1586 qemu_iovec_reset(&hd_qiov); 1587 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, 1588 cur_nr_sectors * 512); 1589 1590 if (bs->encrypted) { 1591 Error *err = NULL; 1592 assert(s->cipher); 1593 if (!cluster_data) { 1594 cluster_data = qemu_try_blockalign(bs->file->bs, 1595 QCOW_MAX_CRYPT_CLUSTERS 1596 * s->cluster_size); 1597 if (cluster_data == NULL) { 1598 ret = -ENOMEM; 1599 goto fail; 1600 } 1601 } 1602 1603 assert(hd_qiov.size <= 1604 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1605 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1606 1607 if (qcow2_encrypt_sectors(s, sector_num, cluster_data, 1608 cluster_data, cur_nr_sectors, 1609 true, &err) < 0) { 1610 error_free(err); 1611 ret = -EIO; 1612 goto fail; 1613 } 1614 1615 qemu_iovec_reset(&hd_qiov); 1616 qemu_iovec_add(&hd_qiov, cluster_data, 1617 cur_nr_sectors * 512); 1618 } 1619 1620 ret = qcow2_pre_write_overlap_check(bs, 0, 1621 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, 1622 cur_nr_sectors * BDRV_SECTOR_SIZE); 1623 if (ret < 0) { 1624 goto fail; 1625 } 1626 1627 qemu_co_mutex_unlock(&s->lock); 1628 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1629 trace_qcow2_writev_data(qemu_coroutine_self(), 1630 (cluster_offset >> 9) + index_in_cluster); 1631 ret = bdrv_co_writev(bs->file->bs, 1632 (cluster_offset >> 9) + index_in_cluster, 1633 cur_nr_sectors, &hd_qiov); 1634 qemu_co_mutex_lock(&s->lock); 1635 if (ret < 0) { 1636 goto fail; 1637 } 1638 1639 while (l2meta != NULL) { 1640 QCowL2Meta *next; 1641 1642 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1643 if (ret < 0) { 1644 goto fail; 1645 } 1646 1647 /* Take the request off the list of running requests */ 1648 if (l2meta->nb_clusters != 0) { 1649 QLIST_REMOVE(l2meta, next_in_flight); 1650 } 1651 1652 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1653 1654 next = l2meta->next; 1655 g_free(l2meta); 1656 l2meta = next; 1657 } 1658 1659 remaining_sectors -= cur_nr_sectors; 1660 sector_num += cur_nr_sectors; 1661 bytes_done += cur_nr_sectors * 512; 1662 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors); 1663 } 1664 ret = 0; 1665 1666 fail: 1667 qemu_co_mutex_unlock(&s->lock); 1668 1669 while (l2meta != NULL) { 1670 QCowL2Meta *next; 1671 1672 if (l2meta->nb_clusters != 0) { 1673 QLIST_REMOVE(l2meta, next_in_flight); 1674 } 1675 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1676 1677 next = l2meta->next; 1678 g_free(l2meta); 1679 l2meta = next; 1680 } 1681 1682 qemu_iovec_destroy(&hd_qiov); 1683 qemu_vfree(cluster_data); 1684 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1685 1686 return ret; 1687 } 1688 1689 static int qcow2_inactivate(BlockDriverState *bs) 1690 { 1691 BDRVQcow2State *s = bs->opaque; 1692 int ret, result = 0; 1693 1694 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1695 if (ret) { 1696 result = ret; 1697 error_report("Failed to flush the L2 table cache: %s", 1698 strerror(-ret)); 1699 } 1700 1701 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1702 if (ret) { 1703 result = ret; 1704 error_report("Failed to flush the refcount block cache: %s", 1705 strerror(-ret)); 1706 } 1707 1708 if (result == 0) { 1709 qcow2_mark_clean(bs); 1710 } 1711 1712 return result; 1713 } 1714 1715 static void qcow2_close(BlockDriverState *bs) 1716 { 1717 BDRVQcow2State *s = bs->opaque; 1718 qemu_vfree(s->l1_table); 1719 /* else pre-write overlap checks in cache_destroy may crash */ 1720 s->l1_table = NULL; 1721 1722 if (!(s->flags & BDRV_O_INACTIVE)) { 1723 qcow2_inactivate(bs); 1724 } 1725 1726 cache_clean_timer_del(bs); 1727 qcow2_cache_destroy(bs, s->l2_table_cache); 1728 qcow2_cache_destroy(bs, s->refcount_block_cache); 1729 1730 qcrypto_cipher_free(s->cipher); 1731 s->cipher = NULL; 1732 1733 g_free(s->unknown_header_fields); 1734 cleanup_unknown_header_ext(bs); 1735 1736 g_free(s->image_backing_file); 1737 g_free(s->image_backing_format); 1738 1739 g_free(s->cluster_cache); 1740 qemu_vfree(s->cluster_data); 1741 qcow2_refcount_close(bs); 1742 qcow2_free_snapshots(bs); 1743 } 1744 1745 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1746 { 1747 BDRVQcow2State *s = bs->opaque; 1748 int flags = s->flags; 1749 QCryptoCipher *cipher = NULL; 1750 QDict *options; 1751 Error *local_err = NULL; 1752 int ret; 1753 1754 /* 1755 * Backing files are read-only which makes all of their metadata immutable, 1756 * that means we don't have to worry about reopening them here. 1757 */ 1758 1759 cipher = s->cipher; 1760 s->cipher = NULL; 1761 1762 qcow2_close(bs); 1763 1764 bdrv_invalidate_cache(bs->file->bs, &local_err); 1765 if (local_err) { 1766 error_propagate(errp, local_err); 1767 bs->drv = NULL; 1768 return; 1769 } 1770 1771 memset(s, 0, sizeof(BDRVQcow2State)); 1772 options = qdict_clone_shallow(bs->options); 1773 1774 flags &= ~BDRV_O_INACTIVE; 1775 ret = qcow2_open(bs, options, flags, &local_err); 1776 QDECREF(options); 1777 if (local_err) { 1778 error_propagate(errp, local_err); 1779 error_prepend(errp, "Could not reopen qcow2 layer: "); 1780 bs->drv = NULL; 1781 return; 1782 } else if (ret < 0) { 1783 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1784 bs->drv = NULL; 1785 return; 1786 } 1787 1788 s->cipher = cipher; 1789 } 1790 1791 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1792 size_t len, size_t buflen) 1793 { 1794 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1795 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1796 1797 if (buflen < ext_len) { 1798 return -ENOSPC; 1799 } 1800 1801 *ext_backing_fmt = (QCowExtension) { 1802 .magic = cpu_to_be32(magic), 1803 .len = cpu_to_be32(len), 1804 }; 1805 memcpy(buf + sizeof(QCowExtension), s, len); 1806 1807 return ext_len; 1808 } 1809 1810 /* 1811 * Updates the qcow2 header, including the variable length parts of it, i.e. 1812 * the backing file name and all extensions. qcow2 was not designed to allow 1813 * such changes, so if we run out of space (we can only use the first cluster) 1814 * this function may fail. 1815 * 1816 * Returns 0 on success, -errno in error cases. 1817 */ 1818 int qcow2_update_header(BlockDriverState *bs) 1819 { 1820 BDRVQcow2State *s = bs->opaque; 1821 QCowHeader *header; 1822 char *buf; 1823 size_t buflen = s->cluster_size; 1824 int ret; 1825 uint64_t total_size; 1826 uint32_t refcount_table_clusters; 1827 size_t header_length; 1828 Qcow2UnknownHeaderExtension *uext; 1829 1830 buf = qemu_blockalign(bs, buflen); 1831 1832 /* Header structure */ 1833 header = (QCowHeader*) buf; 1834 1835 if (buflen < sizeof(*header)) { 1836 ret = -ENOSPC; 1837 goto fail; 1838 } 1839 1840 header_length = sizeof(*header) + s->unknown_header_fields_size; 1841 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1842 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1843 1844 *header = (QCowHeader) { 1845 /* Version 2 fields */ 1846 .magic = cpu_to_be32(QCOW_MAGIC), 1847 .version = cpu_to_be32(s->qcow_version), 1848 .backing_file_offset = 0, 1849 .backing_file_size = 0, 1850 .cluster_bits = cpu_to_be32(s->cluster_bits), 1851 .size = cpu_to_be64(total_size), 1852 .crypt_method = cpu_to_be32(s->crypt_method_header), 1853 .l1_size = cpu_to_be32(s->l1_size), 1854 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1855 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1856 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1857 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1858 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1859 1860 /* Version 3 fields */ 1861 .incompatible_features = cpu_to_be64(s->incompatible_features), 1862 .compatible_features = cpu_to_be64(s->compatible_features), 1863 .autoclear_features = cpu_to_be64(s->autoclear_features), 1864 .refcount_order = cpu_to_be32(s->refcount_order), 1865 .header_length = cpu_to_be32(header_length), 1866 }; 1867 1868 /* For older versions, write a shorter header */ 1869 switch (s->qcow_version) { 1870 case 2: 1871 ret = offsetof(QCowHeader, incompatible_features); 1872 break; 1873 case 3: 1874 ret = sizeof(*header); 1875 break; 1876 default: 1877 ret = -EINVAL; 1878 goto fail; 1879 } 1880 1881 buf += ret; 1882 buflen -= ret; 1883 memset(buf, 0, buflen); 1884 1885 /* Preserve any unknown field in the header */ 1886 if (s->unknown_header_fields_size) { 1887 if (buflen < s->unknown_header_fields_size) { 1888 ret = -ENOSPC; 1889 goto fail; 1890 } 1891 1892 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1893 buf += s->unknown_header_fields_size; 1894 buflen -= s->unknown_header_fields_size; 1895 } 1896 1897 /* Backing file format header extension */ 1898 if (s->image_backing_format) { 1899 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1900 s->image_backing_format, 1901 strlen(s->image_backing_format), 1902 buflen); 1903 if (ret < 0) { 1904 goto fail; 1905 } 1906 1907 buf += ret; 1908 buflen -= ret; 1909 } 1910 1911 /* Feature table */ 1912 if (s->qcow_version >= 3) { 1913 Qcow2Feature features[] = { 1914 { 1915 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1916 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1917 .name = "dirty bit", 1918 }, 1919 { 1920 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1921 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1922 .name = "corrupt bit", 1923 }, 1924 { 1925 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1926 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1927 .name = "lazy refcounts", 1928 }, 1929 }; 1930 1931 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1932 features, sizeof(features), buflen); 1933 if (ret < 0) { 1934 goto fail; 1935 } 1936 buf += ret; 1937 buflen -= ret; 1938 } 1939 1940 /* Keep unknown header extensions */ 1941 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1942 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1943 if (ret < 0) { 1944 goto fail; 1945 } 1946 1947 buf += ret; 1948 buflen -= ret; 1949 } 1950 1951 /* End of header extensions */ 1952 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1953 if (ret < 0) { 1954 goto fail; 1955 } 1956 1957 buf += ret; 1958 buflen -= ret; 1959 1960 /* Backing file name */ 1961 if (s->image_backing_file) { 1962 size_t backing_file_len = strlen(s->image_backing_file); 1963 1964 if (buflen < backing_file_len) { 1965 ret = -ENOSPC; 1966 goto fail; 1967 } 1968 1969 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1970 strncpy(buf, s->image_backing_file, buflen); 1971 1972 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1973 header->backing_file_size = cpu_to_be32(backing_file_len); 1974 } 1975 1976 /* Write the new header */ 1977 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size); 1978 if (ret < 0) { 1979 goto fail; 1980 } 1981 1982 ret = 0; 1983 fail: 1984 qemu_vfree(header); 1985 return ret; 1986 } 1987 1988 static int qcow2_change_backing_file(BlockDriverState *bs, 1989 const char *backing_file, const char *backing_fmt) 1990 { 1991 BDRVQcow2State *s = bs->opaque; 1992 1993 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 1994 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 1995 1996 g_free(s->image_backing_file); 1997 g_free(s->image_backing_format); 1998 1999 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2000 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2001 2002 return qcow2_update_header(bs); 2003 } 2004 2005 static int preallocate(BlockDriverState *bs) 2006 { 2007 uint64_t nb_sectors; 2008 uint64_t offset; 2009 uint64_t host_offset = 0; 2010 int num; 2011 int ret; 2012 QCowL2Meta *meta; 2013 2014 nb_sectors = bdrv_nb_sectors(bs); 2015 offset = 0; 2016 2017 while (nb_sectors) { 2018 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS); 2019 ret = qcow2_alloc_cluster_offset(bs, offset, &num, 2020 &host_offset, &meta); 2021 if (ret < 0) { 2022 return ret; 2023 } 2024 2025 while (meta) { 2026 QCowL2Meta *next = meta->next; 2027 2028 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2029 if (ret < 0) { 2030 qcow2_free_any_clusters(bs, meta->alloc_offset, 2031 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2032 return ret; 2033 } 2034 2035 /* There are no dependent requests, but we need to remove our 2036 * request from the list of in-flight requests */ 2037 QLIST_REMOVE(meta, next_in_flight); 2038 2039 g_free(meta); 2040 meta = next; 2041 } 2042 2043 /* TODO Preallocate data if requested */ 2044 2045 nb_sectors -= num; 2046 offset += num << BDRV_SECTOR_BITS; 2047 } 2048 2049 /* 2050 * It is expected that the image file is large enough to actually contain 2051 * all of the allocated clusters (otherwise we get failing reads after 2052 * EOF). Extend the image to the last allocated sector. 2053 */ 2054 if (host_offset != 0) { 2055 uint8_t buf[BDRV_SECTOR_SIZE]; 2056 memset(buf, 0, BDRV_SECTOR_SIZE); 2057 ret = bdrv_write(bs->file->bs, 2058 (host_offset >> BDRV_SECTOR_BITS) + num - 1, 2059 buf, 1); 2060 if (ret < 0) { 2061 return ret; 2062 } 2063 } 2064 2065 return 0; 2066 } 2067 2068 static int qcow2_create2(const char *filename, int64_t total_size, 2069 const char *backing_file, const char *backing_format, 2070 int flags, size_t cluster_size, PreallocMode prealloc, 2071 QemuOpts *opts, int version, int refcount_order, 2072 Error **errp) 2073 { 2074 int cluster_bits; 2075 QDict *options; 2076 2077 /* Calculate cluster_bits */ 2078 cluster_bits = ctz32(cluster_size); 2079 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2080 (1 << cluster_bits) != cluster_size) 2081 { 2082 error_setg(errp, "Cluster size must be a power of two between %d and " 2083 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2084 return -EINVAL; 2085 } 2086 2087 /* 2088 * Open the image file and write a minimal qcow2 header. 2089 * 2090 * We keep things simple and start with a zero-sized image. We also 2091 * do without refcount blocks or a L1 table for now. We'll fix the 2092 * inconsistency later. 2093 * 2094 * We do need a refcount table because growing the refcount table means 2095 * allocating two new refcount blocks - the seconds of which would be at 2096 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2097 * size for any qcow2 image. 2098 */ 2099 BlockDriverState* bs; 2100 QCowHeader *header; 2101 uint64_t* refcount_table; 2102 Error *local_err = NULL; 2103 int ret; 2104 2105 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2106 /* Note: The following calculation does not need to be exact; if it is a 2107 * bit off, either some bytes will be "leaked" (which is fine) or we 2108 * will need to increase the file size by some bytes (which is fine, 2109 * too, as long as the bulk is allocated here). Therefore, using 2110 * floating point arithmetic is fine. */ 2111 int64_t meta_size = 0; 2112 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2113 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2114 int refblock_bits, refblock_size; 2115 /* refcount entry size in bytes */ 2116 double rces = (1 << refcount_order) / 8.; 2117 2118 /* see qcow2_open() */ 2119 refblock_bits = cluster_bits - (refcount_order - 3); 2120 refblock_size = 1 << refblock_bits; 2121 2122 /* header: 1 cluster */ 2123 meta_size += cluster_size; 2124 2125 /* total size of L2 tables */ 2126 nl2e = aligned_total_size / cluster_size; 2127 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2128 meta_size += nl2e * sizeof(uint64_t); 2129 2130 /* total size of L1 tables */ 2131 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2132 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2133 meta_size += nl1e * sizeof(uint64_t); 2134 2135 /* total size of refcount blocks 2136 * 2137 * note: every host cluster is reference-counted, including metadata 2138 * (even refcount blocks are recursively included). 2139 * Let: 2140 * a = total_size (this is the guest disk size) 2141 * m = meta size not including refcount blocks and refcount tables 2142 * c = cluster size 2143 * y1 = number of refcount blocks entries 2144 * y2 = meta size including everything 2145 * rces = refcount entry size in bytes 2146 * then, 2147 * y1 = (y2 + a)/c 2148 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2149 * we can get y1: 2150 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2151 */ 2152 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2153 / (cluster_size - rces - rces * sizeof(uint64_t) 2154 / cluster_size); 2155 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2156 2157 /* total size of refcount tables */ 2158 nreftablee = nrefblocke / refblock_size; 2159 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2160 meta_size += nreftablee * sizeof(uint64_t); 2161 2162 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2163 aligned_total_size + meta_size, &error_abort); 2164 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2165 &error_abort); 2166 } 2167 2168 ret = bdrv_create_file(filename, opts, &local_err); 2169 if (ret < 0) { 2170 error_propagate(errp, local_err); 2171 return ret; 2172 } 2173 2174 bs = NULL; 2175 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL, 2176 &local_err); 2177 if (ret < 0) { 2178 error_propagate(errp, local_err); 2179 return ret; 2180 } 2181 2182 /* Write the header */ 2183 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2184 header = g_malloc0(cluster_size); 2185 *header = (QCowHeader) { 2186 .magic = cpu_to_be32(QCOW_MAGIC), 2187 .version = cpu_to_be32(version), 2188 .cluster_bits = cpu_to_be32(cluster_bits), 2189 .size = cpu_to_be64(0), 2190 .l1_table_offset = cpu_to_be64(0), 2191 .l1_size = cpu_to_be32(0), 2192 .refcount_table_offset = cpu_to_be64(cluster_size), 2193 .refcount_table_clusters = cpu_to_be32(1), 2194 .refcount_order = cpu_to_be32(refcount_order), 2195 .header_length = cpu_to_be32(sizeof(*header)), 2196 }; 2197 2198 if (flags & BLOCK_FLAG_ENCRYPT) { 2199 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2200 } else { 2201 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2202 } 2203 2204 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2205 header->compatible_features |= 2206 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2207 } 2208 2209 ret = bdrv_pwrite(bs, 0, header, cluster_size); 2210 g_free(header); 2211 if (ret < 0) { 2212 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2213 goto out; 2214 } 2215 2216 /* Write a refcount table with one refcount block */ 2217 refcount_table = g_malloc0(2 * cluster_size); 2218 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2219 ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size); 2220 g_free(refcount_table); 2221 2222 if (ret < 0) { 2223 error_setg_errno(errp, -ret, "Could not write refcount table"); 2224 goto out; 2225 } 2226 2227 bdrv_unref(bs); 2228 bs = NULL; 2229 2230 /* 2231 * And now open the image and make it consistent first (i.e. increase the 2232 * refcount of the cluster that is occupied by the header and the refcount 2233 * table) 2234 */ 2235 options = qdict_new(); 2236 qdict_put(options, "driver", qstring_from_str("qcow2")); 2237 ret = bdrv_open(&bs, filename, NULL, options, 2238 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, 2239 &local_err); 2240 if (ret < 0) { 2241 error_propagate(errp, local_err); 2242 goto out; 2243 } 2244 2245 ret = qcow2_alloc_clusters(bs, 3 * cluster_size); 2246 if (ret < 0) { 2247 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2248 "header and refcount table"); 2249 goto out; 2250 2251 } else if (ret != 0) { 2252 error_report("Huh, first cluster in empty image is already in use?"); 2253 abort(); 2254 } 2255 2256 /* Create a full header (including things like feature table) */ 2257 ret = qcow2_update_header(bs); 2258 if (ret < 0) { 2259 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2260 goto out; 2261 } 2262 2263 /* Okay, now that we have a valid image, let's give it the right size */ 2264 ret = bdrv_truncate(bs, total_size); 2265 if (ret < 0) { 2266 error_setg_errno(errp, -ret, "Could not resize image"); 2267 goto out; 2268 } 2269 2270 /* Want a backing file? There you go.*/ 2271 if (backing_file) { 2272 ret = bdrv_change_backing_file(bs, backing_file, backing_format); 2273 if (ret < 0) { 2274 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2275 "with format '%s'", backing_file, backing_format); 2276 goto out; 2277 } 2278 } 2279 2280 /* And if we're supposed to preallocate metadata, do that now */ 2281 if (prealloc != PREALLOC_MODE_OFF) { 2282 BDRVQcow2State *s = bs->opaque; 2283 qemu_co_mutex_lock(&s->lock); 2284 ret = preallocate(bs); 2285 qemu_co_mutex_unlock(&s->lock); 2286 if (ret < 0) { 2287 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2288 goto out; 2289 } 2290 } 2291 2292 bdrv_unref(bs); 2293 bs = NULL; 2294 2295 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2296 options = qdict_new(); 2297 qdict_put(options, "driver", qstring_from_str("qcow2")); 2298 ret = bdrv_open(&bs, filename, NULL, options, 2299 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, 2300 &local_err); 2301 if (local_err) { 2302 error_propagate(errp, local_err); 2303 goto out; 2304 } 2305 2306 ret = 0; 2307 out: 2308 if (bs) { 2309 bdrv_unref(bs); 2310 } 2311 return ret; 2312 } 2313 2314 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2315 { 2316 char *backing_file = NULL; 2317 char *backing_fmt = NULL; 2318 char *buf = NULL; 2319 uint64_t size = 0; 2320 int flags = 0; 2321 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2322 PreallocMode prealloc; 2323 int version = 3; 2324 uint64_t refcount_bits = 16; 2325 int refcount_order; 2326 Error *local_err = NULL; 2327 int ret; 2328 2329 /* Read out options */ 2330 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2331 BDRV_SECTOR_SIZE); 2332 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2333 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2334 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2335 flags |= BLOCK_FLAG_ENCRYPT; 2336 } 2337 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2338 DEFAULT_CLUSTER_SIZE); 2339 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2340 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2341 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2342 &local_err); 2343 if (local_err) { 2344 error_propagate(errp, local_err); 2345 ret = -EINVAL; 2346 goto finish; 2347 } 2348 g_free(buf); 2349 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2350 if (!buf) { 2351 /* keep the default */ 2352 } else if (!strcmp(buf, "0.10")) { 2353 version = 2; 2354 } else if (!strcmp(buf, "1.1")) { 2355 version = 3; 2356 } else { 2357 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2358 ret = -EINVAL; 2359 goto finish; 2360 } 2361 2362 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2363 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2364 } 2365 2366 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2367 error_setg(errp, "Backing file and preallocation cannot be used at " 2368 "the same time"); 2369 ret = -EINVAL; 2370 goto finish; 2371 } 2372 2373 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2374 error_setg(errp, "Lazy refcounts only supported with compatibility " 2375 "level 1.1 and above (use compat=1.1 or greater)"); 2376 ret = -EINVAL; 2377 goto finish; 2378 } 2379 2380 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2381 refcount_bits); 2382 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2383 error_setg(errp, "Refcount width must be a power of two and may not " 2384 "exceed 64 bits"); 2385 ret = -EINVAL; 2386 goto finish; 2387 } 2388 2389 if (version < 3 && refcount_bits != 16) { 2390 error_setg(errp, "Different refcount widths than 16 bits require " 2391 "compatibility level 1.1 or above (use compat=1.1 or " 2392 "greater)"); 2393 ret = -EINVAL; 2394 goto finish; 2395 } 2396 2397 refcount_order = ctz32(refcount_bits); 2398 2399 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2400 cluster_size, prealloc, opts, version, refcount_order, 2401 &local_err); 2402 if (local_err) { 2403 error_propagate(errp, local_err); 2404 } 2405 2406 finish: 2407 g_free(backing_file); 2408 g_free(backing_fmt); 2409 g_free(buf); 2410 return ret; 2411 } 2412 2413 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs, 2414 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags) 2415 { 2416 int ret; 2417 BDRVQcow2State *s = bs->opaque; 2418 2419 /* Emulate misaligned zero writes */ 2420 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) { 2421 return -ENOTSUP; 2422 } 2423 2424 /* Whatever is left can use real zero clusters */ 2425 qemu_co_mutex_lock(&s->lock); 2426 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2427 nb_sectors); 2428 qemu_co_mutex_unlock(&s->lock); 2429 2430 return ret; 2431 } 2432 2433 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs, 2434 int64_t sector_num, int nb_sectors) 2435 { 2436 int ret; 2437 BDRVQcow2State *s = bs->opaque; 2438 2439 qemu_co_mutex_lock(&s->lock); 2440 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS, 2441 nb_sectors, QCOW2_DISCARD_REQUEST, false); 2442 qemu_co_mutex_unlock(&s->lock); 2443 return ret; 2444 } 2445 2446 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2447 { 2448 BDRVQcow2State *s = bs->opaque; 2449 int64_t new_l1_size; 2450 int ret; 2451 2452 if (offset & 511) { 2453 error_report("The new size must be a multiple of 512"); 2454 return -EINVAL; 2455 } 2456 2457 /* cannot proceed if image has snapshots */ 2458 if (s->nb_snapshots) { 2459 error_report("Can't resize an image which has snapshots"); 2460 return -ENOTSUP; 2461 } 2462 2463 /* shrinking is currently not supported */ 2464 if (offset < bs->total_sectors * 512) { 2465 error_report("qcow2 doesn't support shrinking images yet"); 2466 return -ENOTSUP; 2467 } 2468 2469 new_l1_size = size_to_l1(s, offset); 2470 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2471 if (ret < 0) { 2472 return ret; 2473 } 2474 2475 /* write updated header.size */ 2476 offset = cpu_to_be64(offset); 2477 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size), 2478 &offset, sizeof(uint64_t)); 2479 if (ret < 0) { 2480 return ret; 2481 } 2482 2483 s->l1_vm_state_index = new_l1_size; 2484 return 0; 2485 } 2486 2487 /* XXX: put compressed sectors first, then all the cluster aligned 2488 tables to avoid losing bytes in alignment */ 2489 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2490 const uint8_t *buf, int nb_sectors) 2491 { 2492 BDRVQcow2State *s = bs->opaque; 2493 z_stream strm; 2494 int ret, out_len; 2495 uint8_t *out_buf; 2496 uint64_t cluster_offset; 2497 2498 if (nb_sectors == 0) { 2499 /* align end of file to a sector boundary to ease reading with 2500 sector based I/Os */ 2501 cluster_offset = bdrv_getlength(bs->file->bs); 2502 return bdrv_truncate(bs->file->bs, cluster_offset); 2503 } 2504 2505 if (nb_sectors != s->cluster_sectors) { 2506 ret = -EINVAL; 2507 2508 /* Zero-pad last write if image size is not cluster aligned */ 2509 if (sector_num + nb_sectors == bs->total_sectors && 2510 nb_sectors < s->cluster_sectors) { 2511 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2512 memset(pad_buf, 0, s->cluster_size); 2513 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2514 ret = qcow2_write_compressed(bs, sector_num, 2515 pad_buf, s->cluster_sectors); 2516 qemu_vfree(pad_buf); 2517 } 2518 return ret; 2519 } 2520 2521 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2522 2523 /* best compression, small window, no zlib header */ 2524 memset(&strm, 0, sizeof(strm)); 2525 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2526 Z_DEFLATED, -12, 2527 9, Z_DEFAULT_STRATEGY); 2528 if (ret != 0) { 2529 ret = -EINVAL; 2530 goto fail; 2531 } 2532 2533 strm.avail_in = s->cluster_size; 2534 strm.next_in = (uint8_t *)buf; 2535 strm.avail_out = s->cluster_size; 2536 strm.next_out = out_buf; 2537 2538 ret = deflate(&strm, Z_FINISH); 2539 if (ret != Z_STREAM_END && ret != Z_OK) { 2540 deflateEnd(&strm); 2541 ret = -EINVAL; 2542 goto fail; 2543 } 2544 out_len = strm.next_out - out_buf; 2545 2546 deflateEnd(&strm); 2547 2548 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2549 /* could not compress: write normal cluster */ 2550 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 2551 if (ret < 0) { 2552 goto fail; 2553 } 2554 } else { 2555 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2556 sector_num << 9, out_len); 2557 if (!cluster_offset) { 2558 ret = -EIO; 2559 goto fail; 2560 } 2561 cluster_offset &= s->cluster_offset_mask; 2562 2563 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2564 if (ret < 0) { 2565 goto fail; 2566 } 2567 2568 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2569 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 2570 if (ret < 0) { 2571 goto fail; 2572 } 2573 } 2574 2575 ret = 0; 2576 fail: 2577 g_free(out_buf); 2578 return ret; 2579 } 2580 2581 static int make_completely_empty(BlockDriverState *bs) 2582 { 2583 BDRVQcow2State *s = bs->opaque; 2584 int ret, l1_clusters; 2585 int64_t offset; 2586 uint64_t *new_reftable = NULL; 2587 uint64_t rt_entry, l1_size2; 2588 struct { 2589 uint64_t l1_offset; 2590 uint64_t reftable_offset; 2591 uint32_t reftable_clusters; 2592 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2593 2594 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2595 if (ret < 0) { 2596 goto fail; 2597 } 2598 2599 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2600 if (ret < 0) { 2601 goto fail; 2602 } 2603 2604 /* Refcounts will be broken utterly */ 2605 ret = qcow2_mark_dirty(bs); 2606 if (ret < 0) { 2607 goto fail; 2608 } 2609 2610 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2611 2612 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2613 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2614 2615 /* After this call, neither the in-memory nor the on-disk refcount 2616 * information accurately describe the actual references */ 2617 2618 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE, 2619 l1_clusters * s->cluster_sectors, 0); 2620 if (ret < 0) { 2621 goto fail_broken_refcounts; 2622 } 2623 memset(s->l1_table, 0, l1_size2); 2624 2625 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2626 2627 /* Overwrite enough clusters at the beginning of the sectors to place 2628 * the refcount table, a refcount block and the L1 table in; this may 2629 * overwrite parts of the existing refcount and L1 table, which is not 2630 * an issue because the dirty flag is set, complete data loss is in fact 2631 * desired and partial data loss is consequently fine as well */ 2632 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE, 2633 (2 + l1_clusters) * s->cluster_size / 2634 BDRV_SECTOR_SIZE, 0); 2635 /* This call (even if it failed overall) may have overwritten on-disk 2636 * refcount structures; in that case, the in-memory refcount information 2637 * will probably differ from the on-disk information which makes the BDS 2638 * unusable */ 2639 if (ret < 0) { 2640 goto fail_broken_refcounts; 2641 } 2642 2643 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2644 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2645 2646 /* "Create" an empty reftable (one cluster) directly after the image 2647 * header and an empty L1 table three clusters after the image header; 2648 * the cluster between those two will be used as the first refblock */ 2649 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size); 2650 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size); 2651 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1); 2652 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset), 2653 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2654 if (ret < 0) { 2655 goto fail_broken_refcounts; 2656 } 2657 2658 s->l1_table_offset = 3 * s->cluster_size; 2659 2660 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2661 if (!new_reftable) { 2662 ret = -ENOMEM; 2663 goto fail_broken_refcounts; 2664 } 2665 2666 s->refcount_table_offset = s->cluster_size; 2667 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2668 2669 g_free(s->refcount_table); 2670 s->refcount_table = new_reftable; 2671 new_reftable = NULL; 2672 2673 /* Now the in-memory refcount information again corresponds to the on-disk 2674 * information (reftable is empty and no refblocks (the refblock cache is 2675 * empty)); however, this means some clusters (e.g. the image header) are 2676 * referenced, but not refcounted, but the normal qcow2 code assumes that 2677 * the in-memory information is always correct */ 2678 2679 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2680 2681 /* Enter the first refblock into the reftable */ 2682 rt_entry = cpu_to_be64(2 * s->cluster_size); 2683 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size, 2684 &rt_entry, sizeof(rt_entry)); 2685 if (ret < 0) { 2686 goto fail_broken_refcounts; 2687 } 2688 s->refcount_table[0] = 2 * s->cluster_size; 2689 2690 s->free_cluster_index = 0; 2691 assert(3 + l1_clusters <= s->refcount_block_size); 2692 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2693 if (offset < 0) { 2694 ret = offset; 2695 goto fail_broken_refcounts; 2696 } else if (offset > 0) { 2697 error_report("First cluster in emptied image is in use"); 2698 abort(); 2699 } 2700 2701 /* Now finally the in-memory information corresponds to the on-disk 2702 * structures and is correct */ 2703 ret = qcow2_mark_clean(bs); 2704 if (ret < 0) { 2705 goto fail; 2706 } 2707 2708 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2709 if (ret < 0) { 2710 goto fail; 2711 } 2712 2713 return 0; 2714 2715 fail_broken_refcounts: 2716 /* The BDS is unusable at this point. If we wanted to make it usable, we 2717 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2718 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2719 * again. However, because the functions which could have caused this error 2720 * path to be taken are used by those functions as well, it's very likely 2721 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2722 bs->drv = NULL; 2723 2724 fail: 2725 g_free(new_reftable); 2726 return ret; 2727 } 2728 2729 static int qcow2_make_empty(BlockDriverState *bs) 2730 { 2731 BDRVQcow2State *s = bs->opaque; 2732 uint64_t start_sector; 2733 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2734 int l1_clusters, ret = 0; 2735 2736 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2737 2738 if (s->qcow_version >= 3 && !s->snapshots && 2739 3 + l1_clusters <= s->refcount_block_size) { 2740 /* The following function only works for qcow2 v3 images (it requires 2741 * the dirty flag) and only as long as there are no snapshots (because 2742 * it completely empties the image). Furthermore, the L1 table and three 2743 * additional clusters (image header, refcount table, one refcount 2744 * block) have to fit inside one refcount block. */ 2745 return make_completely_empty(bs); 2746 } 2747 2748 /* This fallback code simply discards every active cluster; this is slow, 2749 * but works in all cases */ 2750 for (start_sector = 0; start_sector < bs->total_sectors; 2751 start_sector += sector_step) 2752 { 2753 /* As this function is generally used after committing an external 2754 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2755 * default action for this kind of discard is to pass the discard, 2756 * which will ideally result in an actually smaller image file, as 2757 * is probably desired. */ 2758 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2759 MIN(sector_step, 2760 bs->total_sectors - start_sector), 2761 QCOW2_DISCARD_SNAPSHOT, true); 2762 if (ret < 0) { 2763 break; 2764 } 2765 } 2766 2767 return ret; 2768 } 2769 2770 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2771 { 2772 BDRVQcow2State *s = bs->opaque; 2773 int ret; 2774 2775 qemu_co_mutex_lock(&s->lock); 2776 ret = qcow2_cache_flush(bs, s->l2_table_cache); 2777 if (ret < 0) { 2778 qemu_co_mutex_unlock(&s->lock); 2779 return ret; 2780 } 2781 2782 if (qcow2_need_accurate_refcounts(s)) { 2783 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 2784 if (ret < 0) { 2785 qemu_co_mutex_unlock(&s->lock); 2786 return ret; 2787 } 2788 } 2789 qemu_co_mutex_unlock(&s->lock); 2790 2791 return 0; 2792 } 2793 2794 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2795 { 2796 BDRVQcow2State *s = bs->opaque; 2797 bdi->unallocated_blocks_are_zero = true; 2798 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2799 bdi->cluster_size = s->cluster_size; 2800 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2801 return 0; 2802 } 2803 2804 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2805 { 2806 BDRVQcow2State *s = bs->opaque; 2807 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2808 2809 *spec_info = (ImageInfoSpecific){ 2810 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2811 .u.qcow2 = g_new(ImageInfoSpecificQCow2, 1), 2812 }; 2813 if (s->qcow_version == 2) { 2814 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2815 .compat = g_strdup("0.10"), 2816 .refcount_bits = s->refcount_bits, 2817 }; 2818 } else if (s->qcow_version == 3) { 2819 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){ 2820 .compat = g_strdup("1.1"), 2821 .lazy_refcounts = s->compatible_features & 2822 QCOW2_COMPAT_LAZY_REFCOUNTS, 2823 .has_lazy_refcounts = true, 2824 .corrupt = s->incompatible_features & 2825 QCOW2_INCOMPAT_CORRUPT, 2826 .has_corrupt = true, 2827 .refcount_bits = s->refcount_bits, 2828 }; 2829 } else { 2830 /* if this assertion fails, this probably means a new version was 2831 * added without having it covered here */ 2832 assert(false); 2833 } 2834 2835 return spec_info; 2836 } 2837 2838 #if 0 2839 static void dump_refcounts(BlockDriverState *bs) 2840 { 2841 BDRVQcow2State *s = bs->opaque; 2842 int64_t nb_clusters, k, k1, size; 2843 int refcount; 2844 2845 size = bdrv_getlength(bs->file->bs); 2846 nb_clusters = size_to_clusters(s, size); 2847 for(k = 0; k < nb_clusters;) { 2848 k1 = k; 2849 refcount = get_refcount(bs, k); 2850 k++; 2851 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2852 k++; 2853 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2854 k - k1); 2855 } 2856 } 2857 #endif 2858 2859 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2860 int64_t pos) 2861 { 2862 BDRVQcow2State *s = bs->opaque; 2863 int64_t total_sectors = bs->total_sectors; 2864 bool zero_beyond_eof = bs->zero_beyond_eof; 2865 int ret; 2866 2867 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2868 bs->zero_beyond_eof = false; 2869 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov); 2870 bs->zero_beyond_eof = zero_beyond_eof; 2871 2872 /* bdrv_co_do_writev will have increased the total_sectors value to include 2873 * the VM state - the VM state is however not an actual part of the block 2874 * device, therefore, we need to restore the old value. */ 2875 bs->total_sectors = total_sectors; 2876 2877 return ret; 2878 } 2879 2880 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf, 2881 int64_t pos, int size) 2882 { 2883 BDRVQcow2State *s = bs->opaque; 2884 bool zero_beyond_eof = bs->zero_beyond_eof; 2885 int ret; 2886 2887 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2888 bs->zero_beyond_eof = false; 2889 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size); 2890 bs->zero_beyond_eof = zero_beyond_eof; 2891 2892 return ret; 2893 } 2894 2895 /* 2896 * Downgrades an image's version. To achieve this, any incompatible features 2897 * have to be removed. 2898 */ 2899 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2900 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2901 { 2902 BDRVQcow2State *s = bs->opaque; 2903 int current_version = s->qcow_version; 2904 int ret; 2905 2906 if (target_version == current_version) { 2907 return 0; 2908 } else if (target_version > current_version) { 2909 return -EINVAL; 2910 } else if (target_version != 2) { 2911 return -EINVAL; 2912 } 2913 2914 if (s->refcount_order != 4) { 2915 error_report("compat=0.10 requires refcount_bits=16"); 2916 return -ENOTSUP; 2917 } 2918 2919 /* clear incompatible features */ 2920 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2921 ret = qcow2_mark_clean(bs); 2922 if (ret < 0) { 2923 return ret; 2924 } 2925 } 2926 2927 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 2928 * the first place; if that happens nonetheless, returning -ENOTSUP is the 2929 * best thing to do anyway */ 2930 2931 if (s->incompatible_features) { 2932 return -ENOTSUP; 2933 } 2934 2935 /* since we can ignore compatible features, we can set them to 0 as well */ 2936 s->compatible_features = 0; 2937 /* if lazy refcounts have been used, they have already been fixed through 2938 * clearing the dirty flag */ 2939 2940 /* clearing autoclear features is trivial */ 2941 s->autoclear_features = 0; 2942 2943 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 2944 if (ret < 0) { 2945 return ret; 2946 } 2947 2948 s->qcow_version = target_version; 2949 ret = qcow2_update_header(bs); 2950 if (ret < 0) { 2951 s->qcow_version = current_version; 2952 return ret; 2953 } 2954 return 0; 2955 } 2956 2957 typedef enum Qcow2AmendOperation { 2958 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 2959 * statically initialized to so that the helper CB can discern the first 2960 * invocation from an operation change */ 2961 QCOW2_NO_OPERATION = 0, 2962 2963 QCOW2_CHANGING_REFCOUNT_ORDER, 2964 QCOW2_DOWNGRADING, 2965 } Qcow2AmendOperation; 2966 2967 typedef struct Qcow2AmendHelperCBInfo { 2968 /* The code coordinating the amend operations should only modify 2969 * these four fields; the rest will be managed by the CB */ 2970 BlockDriverAmendStatusCB *original_status_cb; 2971 void *original_cb_opaque; 2972 2973 Qcow2AmendOperation current_operation; 2974 2975 /* Total number of operations to perform (only set once) */ 2976 int total_operations; 2977 2978 /* The following fields are managed by the CB */ 2979 2980 /* Number of operations completed */ 2981 int operations_completed; 2982 2983 /* Cumulative offset of all completed operations */ 2984 int64_t offset_completed; 2985 2986 Qcow2AmendOperation last_operation; 2987 int64_t last_work_size; 2988 } Qcow2AmendHelperCBInfo; 2989 2990 static void qcow2_amend_helper_cb(BlockDriverState *bs, 2991 int64_t operation_offset, 2992 int64_t operation_work_size, void *opaque) 2993 { 2994 Qcow2AmendHelperCBInfo *info = opaque; 2995 int64_t current_work_size; 2996 int64_t projected_work_size; 2997 2998 if (info->current_operation != info->last_operation) { 2999 if (info->last_operation != QCOW2_NO_OPERATION) { 3000 info->offset_completed += info->last_work_size; 3001 info->operations_completed++; 3002 } 3003 3004 info->last_operation = info->current_operation; 3005 } 3006 3007 assert(info->total_operations > 0); 3008 assert(info->operations_completed < info->total_operations); 3009 3010 info->last_work_size = operation_work_size; 3011 3012 current_work_size = info->offset_completed + operation_work_size; 3013 3014 /* current_work_size is the total work size for (operations_completed + 1) 3015 * operations (which includes this one), so multiply it by the number of 3016 * operations not covered and divide it by the number of operations 3017 * covered to get a projection for the operations not covered */ 3018 projected_work_size = current_work_size * (info->total_operations - 3019 info->operations_completed - 1) 3020 / (info->operations_completed + 1); 3021 3022 info->original_status_cb(bs, info->offset_completed + operation_offset, 3023 current_work_size + projected_work_size, 3024 info->original_cb_opaque); 3025 } 3026 3027 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3028 BlockDriverAmendStatusCB *status_cb, 3029 void *cb_opaque) 3030 { 3031 BDRVQcow2State *s = bs->opaque; 3032 int old_version = s->qcow_version, new_version = old_version; 3033 uint64_t new_size = 0; 3034 const char *backing_file = NULL, *backing_format = NULL; 3035 bool lazy_refcounts = s->use_lazy_refcounts; 3036 const char *compat = NULL; 3037 uint64_t cluster_size = s->cluster_size; 3038 bool encrypt; 3039 int refcount_bits = s->refcount_bits; 3040 int ret; 3041 QemuOptDesc *desc = opts->list->desc; 3042 Qcow2AmendHelperCBInfo helper_cb_info; 3043 3044 while (desc && desc->name) { 3045 if (!qemu_opt_find(opts, desc->name)) { 3046 /* only change explicitly defined options */ 3047 desc++; 3048 continue; 3049 } 3050 3051 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3052 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3053 if (!compat) { 3054 /* preserve default */ 3055 } else if (!strcmp(compat, "0.10")) { 3056 new_version = 2; 3057 } else if (!strcmp(compat, "1.1")) { 3058 new_version = 3; 3059 } else { 3060 error_report("Unknown compatibility level %s", compat); 3061 return -EINVAL; 3062 } 3063 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3064 error_report("Cannot change preallocation mode"); 3065 return -ENOTSUP; 3066 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3067 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3068 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3069 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3070 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3071 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3072 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3073 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3074 !!s->cipher); 3075 3076 if (encrypt != !!s->cipher) { 3077 error_report("Changing the encryption flag is not supported"); 3078 return -ENOTSUP; 3079 } 3080 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3081 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3082 cluster_size); 3083 if (cluster_size != s->cluster_size) { 3084 error_report("Changing the cluster size is not supported"); 3085 return -ENOTSUP; 3086 } 3087 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3088 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3089 lazy_refcounts); 3090 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3091 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3092 refcount_bits); 3093 3094 if (refcount_bits <= 0 || refcount_bits > 64 || 3095 !is_power_of_2(refcount_bits)) 3096 { 3097 error_report("Refcount width must be a power of two and may " 3098 "not exceed 64 bits"); 3099 return -EINVAL; 3100 } 3101 } else { 3102 /* if this point is reached, this probably means a new option was 3103 * added without having it covered here */ 3104 abort(); 3105 } 3106 3107 desc++; 3108 } 3109 3110 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3111 .original_status_cb = status_cb, 3112 .original_cb_opaque = cb_opaque, 3113 .total_operations = (new_version < old_version) 3114 + (s->refcount_bits != refcount_bits) 3115 }; 3116 3117 /* Upgrade first (some features may require compat=1.1) */ 3118 if (new_version > old_version) { 3119 s->qcow_version = new_version; 3120 ret = qcow2_update_header(bs); 3121 if (ret < 0) { 3122 s->qcow_version = old_version; 3123 return ret; 3124 } 3125 } 3126 3127 if (s->refcount_bits != refcount_bits) { 3128 int refcount_order = ctz32(refcount_bits); 3129 Error *local_error = NULL; 3130 3131 if (new_version < 3 && refcount_bits != 16) { 3132 error_report("Different refcount widths than 16 bits require " 3133 "compatibility level 1.1 or above (use compat=1.1 or " 3134 "greater)"); 3135 return -EINVAL; 3136 } 3137 3138 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3139 ret = qcow2_change_refcount_order(bs, refcount_order, 3140 &qcow2_amend_helper_cb, 3141 &helper_cb_info, &local_error); 3142 if (ret < 0) { 3143 error_report_err(local_error); 3144 return ret; 3145 } 3146 } 3147 3148 if (backing_file || backing_format) { 3149 ret = qcow2_change_backing_file(bs, 3150 backing_file ?: s->image_backing_file, 3151 backing_format ?: s->image_backing_format); 3152 if (ret < 0) { 3153 return ret; 3154 } 3155 } 3156 3157 if (s->use_lazy_refcounts != lazy_refcounts) { 3158 if (lazy_refcounts) { 3159 if (new_version < 3) { 3160 error_report("Lazy refcounts only supported with compatibility " 3161 "level 1.1 and above (use compat=1.1 or greater)"); 3162 return -EINVAL; 3163 } 3164 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3165 ret = qcow2_update_header(bs); 3166 if (ret < 0) { 3167 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3168 return ret; 3169 } 3170 s->use_lazy_refcounts = true; 3171 } else { 3172 /* make image clean first */ 3173 ret = qcow2_mark_clean(bs); 3174 if (ret < 0) { 3175 return ret; 3176 } 3177 /* now disallow lazy refcounts */ 3178 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3179 ret = qcow2_update_header(bs); 3180 if (ret < 0) { 3181 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3182 return ret; 3183 } 3184 s->use_lazy_refcounts = false; 3185 } 3186 } 3187 3188 if (new_size) { 3189 ret = bdrv_truncate(bs, new_size); 3190 if (ret < 0) { 3191 return ret; 3192 } 3193 } 3194 3195 /* Downgrade last (so unsupported features can be removed before) */ 3196 if (new_version < old_version) { 3197 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3198 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3199 &helper_cb_info); 3200 if (ret < 0) { 3201 return ret; 3202 } 3203 } 3204 3205 return 0; 3206 } 3207 3208 /* 3209 * If offset or size are negative, respectively, they will not be included in 3210 * the BLOCK_IMAGE_CORRUPTED event emitted. 3211 * fatal will be ignored for read-only BDS; corruptions found there will always 3212 * be considered non-fatal. 3213 */ 3214 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3215 int64_t size, const char *message_format, ...) 3216 { 3217 BDRVQcow2State *s = bs->opaque; 3218 const char *node_name; 3219 char *message; 3220 va_list ap; 3221 3222 fatal = fatal && !bs->read_only; 3223 3224 if (s->signaled_corruption && 3225 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3226 { 3227 return; 3228 } 3229 3230 va_start(ap, message_format); 3231 message = g_strdup_vprintf(message_format, ap); 3232 va_end(ap); 3233 3234 if (fatal) { 3235 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3236 "corruption events will be suppressed\n", message); 3237 } else { 3238 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3239 "corruption events will be suppressed\n", message); 3240 } 3241 3242 node_name = bdrv_get_node_name(bs); 3243 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3244 *node_name != '\0', node_name, 3245 message, offset >= 0, offset, 3246 size >= 0, size, 3247 fatal, &error_abort); 3248 g_free(message); 3249 3250 if (fatal) { 3251 qcow2_mark_corrupt(bs); 3252 bs->drv = NULL; /* make BDS unusable */ 3253 } 3254 3255 s->signaled_corruption = true; 3256 } 3257 3258 static QemuOptsList qcow2_create_opts = { 3259 .name = "qcow2-create-opts", 3260 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3261 .desc = { 3262 { 3263 .name = BLOCK_OPT_SIZE, 3264 .type = QEMU_OPT_SIZE, 3265 .help = "Virtual disk size" 3266 }, 3267 { 3268 .name = BLOCK_OPT_COMPAT_LEVEL, 3269 .type = QEMU_OPT_STRING, 3270 .help = "Compatibility level (0.10 or 1.1)" 3271 }, 3272 { 3273 .name = BLOCK_OPT_BACKING_FILE, 3274 .type = QEMU_OPT_STRING, 3275 .help = "File name of a base image" 3276 }, 3277 { 3278 .name = BLOCK_OPT_BACKING_FMT, 3279 .type = QEMU_OPT_STRING, 3280 .help = "Image format of the base image" 3281 }, 3282 { 3283 .name = BLOCK_OPT_ENCRYPT, 3284 .type = QEMU_OPT_BOOL, 3285 .help = "Encrypt the image", 3286 .def_value_str = "off" 3287 }, 3288 { 3289 .name = BLOCK_OPT_CLUSTER_SIZE, 3290 .type = QEMU_OPT_SIZE, 3291 .help = "qcow2 cluster size", 3292 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3293 }, 3294 { 3295 .name = BLOCK_OPT_PREALLOC, 3296 .type = QEMU_OPT_STRING, 3297 .help = "Preallocation mode (allowed values: off, metadata, " 3298 "falloc, full)" 3299 }, 3300 { 3301 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3302 .type = QEMU_OPT_BOOL, 3303 .help = "Postpone refcount updates", 3304 .def_value_str = "off" 3305 }, 3306 { 3307 .name = BLOCK_OPT_REFCOUNT_BITS, 3308 .type = QEMU_OPT_NUMBER, 3309 .help = "Width of a reference count entry in bits", 3310 .def_value_str = "16" 3311 }, 3312 { /* end of list */ } 3313 } 3314 }; 3315 3316 BlockDriver bdrv_qcow2 = { 3317 .format_name = "qcow2", 3318 .instance_size = sizeof(BDRVQcow2State), 3319 .bdrv_probe = qcow2_probe, 3320 .bdrv_open = qcow2_open, 3321 .bdrv_close = qcow2_close, 3322 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3323 .bdrv_reopen_commit = qcow2_reopen_commit, 3324 .bdrv_reopen_abort = qcow2_reopen_abort, 3325 .bdrv_join_options = qcow2_join_options, 3326 .bdrv_create = qcow2_create, 3327 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3328 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3329 .bdrv_set_key = qcow2_set_key, 3330 3331 .bdrv_co_readv = qcow2_co_readv, 3332 .bdrv_co_writev = qcow2_co_writev, 3333 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3334 3335 .bdrv_co_write_zeroes = qcow2_co_write_zeroes, 3336 .bdrv_co_discard = qcow2_co_discard, 3337 .bdrv_truncate = qcow2_truncate, 3338 .bdrv_write_compressed = qcow2_write_compressed, 3339 .bdrv_make_empty = qcow2_make_empty, 3340 3341 .bdrv_snapshot_create = qcow2_snapshot_create, 3342 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3343 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3344 .bdrv_snapshot_list = qcow2_snapshot_list, 3345 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3346 .bdrv_get_info = qcow2_get_info, 3347 .bdrv_get_specific_info = qcow2_get_specific_info, 3348 3349 .bdrv_save_vmstate = qcow2_save_vmstate, 3350 .bdrv_load_vmstate = qcow2_load_vmstate, 3351 3352 .supports_backing = true, 3353 .bdrv_change_backing_file = qcow2_change_backing_file, 3354 3355 .bdrv_refresh_limits = qcow2_refresh_limits, 3356 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3357 .bdrv_inactivate = qcow2_inactivate, 3358 3359 .create_opts = &qcow2_create_opts, 3360 .bdrv_check = qcow2_check, 3361 .bdrv_amend_options = qcow2_amend_options, 3362 3363 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3364 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3365 }; 3366 3367 static void bdrv_qcow2_init(void) 3368 { 3369 bdrv_register(&bdrv_qcow2); 3370 } 3371 3372 block_init(bdrv_qcow2_init); 3373