1 /* 2 * Block driver for the QCOW version 2 format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #include "qemu/osdep.h" 25 #include "block/block_int.h" 26 #include "sysemu/block-backend.h" 27 #include "qemu/module.h" 28 #include <zlib.h> 29 #include "block/qcow2.h" 30 #include "qemu/error-report.h" 31 #include "qapi/qmp/qerror.h" 32 #include "qapi/qmp/qbool.h" 33 #include "qapi/util.h" 34 #include "qapi/qmp/types.h" 35 #include "qapi-event.h" 36 #include "trace.h" 37 #include "qemu/option_int.h" 38 #include "qemu/cutils.h" 39 #include "qemu/bswap.h" 40 41 /* 42 Differences with QCOW: 43 44 - Support for multiple incremental snapshots. 45 - Memory management by reference counts. 46 - Clusters which have a reference count of one have the bit 47 QCOW_OFLAG_COPIED to optimize write performance. 48 - Size of compressed clusters is stored in sectors to reduce bit usage 49 in the cluster offsets. 50 - Support for storing additional data (such as the VM state) in the 51 snapshots. 52 - If a backing store is used, the cluster size is not constrained 53 (could be backported to QCOW). 54 - L2 tables have always a size of one cluster. 55 */ 56 57 58 typedef struct { 59 uint32_t magic; 60 uint32_t len; 61 } QEMU_PACKED QCowExtension; 62 63 #define QCOW2_EXT_MAGIC_END 0 64 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 65 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 66 67 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 68 { 69 const QCowHeader *cow_header = (const void *)buf; 70 71 if (buf_size >= sizeof(QCowHeader) && 72 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 73 be32_to_cpu(cow_header->version) >= 2) 74 return 100; 75 else 76 return 0; 77 } 78 79 80 /* 81 * read qcow2 extension and fill bs 82 * start reading from start_offset 83 * finish reading upon magic of value 0 or when end_offset reached 84 * unknown magic is skipped (future extension this version knows nothing about) 85 * return 0 upon success, non-0 otherwise 86 */ 87 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 88 uint64_t end_offset, void **p_feature_table, 89 Error **errp) 90 { 91 BDRVQcow2State *s = bs->opaque; 92 QCowExtension ext; 93 uint64_t offset; 94 int ret; 95 96 #ifdef DEBUG_EXT 97 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 98 #endif 99 offset = start_offset; 100 while (offset < end_offset) { 101 102 #ifdef DEBUG_EXT 103 /* Sanity check */ 104 if (offset > s->cluster_size) 105 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 106 107 printf("attempting to read extended header in offset %lu\n", offset); 108 #endif 109 110 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 111 if (ret < 0) { 112 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 113 "pread fail from offset %" PRIu64, offset); 114 return 1; 115 } 116 be32_to_cpus(&ext.magic); 117 be32_to_cpus(&ext.len); 118 offset += sizeof(ext); 119 #ifdef DEBUG_EXT 120 printf("ext.magic = 0x%x\n", ext.magic); 121 #endif 122 if (offset > end_offset || ext.len > end_offset - offset) { 123 error_setg(errp, "Header extension too large"); 124 return -EINVAL; 125 } 126 127 switch (ext.magic) { 128 case QCOW2_EXT_MAGIC_END: 129 return 0; 130 131 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 132 if (ext.len >= sizeof(bs->backing_format)) { 133 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 134 " too large (>=%zu)", ext.len, 135 sizeof(bs->backing_format)); 136 return 2; 137 } 138 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 139 if (ret < 0) { 140 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 141 "Could not read format name"); 142 return 3; 143 } 144 bs->backing_format[ext.len] = '\0'; 145 s->image_backing_format = g_strdup(bs->backing_format); 146 #ifdef DEBUG_EXT 147 printf("Qcow2: Got format extension %s\n", bs->backing_format); 148 #endif 149 break; 150 151 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 152 if (p_feature_table != NULL) { 153 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 154 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 155 if (ret < 0) { 156 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 157 "Could not read table"); 158 return ret; 159 } 160 161 *p_feature_table = feature_table; 162 } 163 break; 164 165 default: 166 /* unknown magic - save it in case we need to rewrite the header */ 167 { 168 Qcow2UnknownHeaderExtension *uext; 169 170 uext = g_malloc0(sizeof(*uext) + ext.len); 171 uext->magic = ext.magic; 172 uext->len = ext.len; 173 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 174 175 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 176 if (ret < 0) { 177 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 178 "Could not read data"); 179 return ret; 180 } 181 } 182 break; 183 } 184 185 offset += ((ext.len + 7) & ~7); 186 } 187 188 return 0; 189 } 190 191 static void cleanup_unknown_header_ext(BlockDriverState *bs) 192 { 193 BDRVQcow2State *s = bs->opaque; 194 Qcow2UnknownHeaderExtension *uext, *next; 195 196 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 197 QLIST_REMOVE(uext, next); 198 g_free(uext); 199 } 200 } 201 202 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 203 uint64_t mask) 204 { 205 char *features = g_strdup(""); 206 char *old; 207 208 while (table && table->name[0] != '\0') { 209 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 210 if (mask & (1ULL << table->bit)) { 211 old = features; 212 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 213 table->name); 214 g_free(old); 215 mask &= ~(1ULL << table->bit); 216 } 217 } 218 table++; 219 } 220 221 if (mask) { 222 old = features; 223 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 224 old, *old ? ", " : "", mask); 225 g_free(old); 226 } 227 228 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 229 g_free(features); 230 } 231 232 /* 233 * Sets the dirty bit and flushes afterwards if necessary. 234 * 235 * The incompatible_features bit is only set if the image file header was 236 * updated successfully. Therefore it is not required to check the return 237 * value of this function. 238 */ 239 int qcow2_mark_dirty(BlockDriverState *bs) 240 { 241 BDRVQcow2State *s = bs->opaque; 242 uint64_t val; 243 int ret; 244 245 assert(s->qcow_version >= 3); 246 247 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 248 return 0; /* already dirty */ 249 } 250 251 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 252 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 253 &val, sizeof(val)); 254 if (ret < 0) { 255 return ret; 256 } 257 ret = bdrv_flush(bs->file->bs); 258 if (ret < 0) { 259 return ret; 260 } 261 262 /* Only treat image as dirty if the header was updated successfully */ 263 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 264 return 0; 265 } 266 267 /* 268 * Clears the dirty bit and flushes before if necessary. Only call this 269 * function when there are no pending requests, it does not guard against 270 * concurrent requests dirtying the image. 271 */ 272 static int qcow2_mark_clean(BlockDriverState *bs) 273 { 274 BDRVQcow2State *s = bs->opaque; 275 276 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 277 int ret; 278 279 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 280 281 ret = bdrv_flush(bs); 282 if (ret < 0) { 283 return ret; 284 } 285 286 return qcow2_update_header(bs); 287 } 288 return 0; 289 } 290 291 /* 292 * Marks the image as corrupt. 293 */ 294 int qcow2_mark_corrupt(BlockDriverState *bs) 295 { 296 BDRVQcow2State *s = bs->opaque; 297 298 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 299 return qcow2_update_header(bs); 300 } 301 302 /* 303 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 304 * before if necessary. 305 */ 306 int qcow2_mark_consistent(BlockDriverState *bs) 307 { 308 BDRVQcow2State *s = bs->opaque; 309 310 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 311 int ret = bdrv_flush(bs); 312 if (ret < 0) { 313 return ret; 314 } 315 316 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 317 return qcow2_update_header(bs); 318 } 319 return 0; 320 } 321 322 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 323 BdrvCheckMode fix) 324 { 325 int ret = qcow2_check_refcounts(bs, result, fix); 326 if (ret < 0) { 327 return ret; 328 } 329 330 if (fix && result->check_errors == 0 && result->corruptions == 0) { 331 ret = qcow2_mark_clean(bs); 332 if (ret < 0) { 333 return ret; 334 } 335 return qcow2_mark_consistent(bs); 336 } 337 return ret; 338 } 339 340 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 341 uint64_t entries, size_t entry_len) 342 { 343 BDRVQcow2State *s = bs->opaque; 344 uint64_t size; 345 346 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 347 * because values will be passed to qemu functions taking int64_t. */ 348 if (entries > INT64_MAX / entry_len) { 349 return -EINVAL; 350 } 351 352 size = entries * entry_len; 353 354 if (INT64_MAX - size < offset) { 355 return -EINVAL; 356 } 357 358 /* Tables must be cluster aligned */ 359 if (offset & (s->cluster_size - 1)) { 360 return -EINVAL; 361 } 362 363 return 0; 364 } 365 366 static QemuOptsList qcow2_runtime_opts = { 367 .name = "qcow2", 368 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 369 .desc = { 370 { 371 .name = QCOW2_OPT_LAZY_REFCOUNTS, 372 .type = QEMU_OPT_BOOL, 373 .help = "Postpone refcount updates", 374 }, 375 { 376 .name = QCOW2_OPT_DISCARD_REQUEST, 377 .type = QEMU_OPT_BOOL, 378 .help = "Pass guest discard requests to the layer below", 379 }, 380 { 381 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 382 .type = QEMU_OPT_BOOL, 383 .help = "Generate discard requests when snapshot related space " 384 "is freed", 385 }, 386 { 387 .name = QCOW2_OPT_DISCARD_OTHER, 388 .type = QEMU_OPT_BOOL, 389 .help = "Generate discard requests when other clusters are freed", 390 }, 391 { 392 .name = QCOW2_OPT_OVERLAP, 393 .type = QEMU_OPT_STRING, 394 .help = "Selects which overlap checks to perform from a range of " 395 "templates (none, constant, cached, all)", 396 }, 397 { 398 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 399 .type = QEMU_OPT_STRING, 400 .help = "Selects which overlap checks to perform from a range of " 401 "templates (none, constant, cached, all)", 402 }, 403 { 404 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 405 .type = QEMU_OPT_BOOL, 406 .help = "Check for unintended writes into the main qcow2 header", 407 }, 408 { 409 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 410 .type = QEMU_OPT_BOOL, 411 .help = "Check for unintended writes into the active L1 table", 412 }, 413 { 414 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 415 .type = QEMU_OPT_BOOL, 416 .help = "Check for unintended writes into an active L2 table", 417 }, 418 { 419 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 420 .type = QEMU_OPT_BOOL, 421 .help = "Check for unintended writes into the refcount table", 422 }, 423 { 424 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 425 .type = QEMU_OPT_BOOL, 426 .help = "Check for unintended writes into a refcount block", 427 }, 428 { 429 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 430 .type = QEMU_OPT_BOOL, 431 .help = "Check for unintended writes into the snapshot table", 432 }, 433 { 434 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 435 .type = QEMU_OPT_BOOL, 436 .help = "Check for unintended writes into an inactive L1 table", 437 }, 438 { 439 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 440 .type = QEMU_OPT_BOOL, 441 .help = "Check for unintended writes into an inactive L2 table", 442 }, 443 { 444 .name = QCOW2_OPT_CACHE_SIZE, 445 .type = QEMU_OPT_SIZE, 446 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 447 "cache size", 448 }, 449 { 450 .name = QCOW2_OPT_L2_CACHE_SIZE, 451 .type = QEMU_OPT_SIZE, 452 .help = "Maximum L2 table cache size", 453 }, 454 { 455 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 456 .type = QEMU_OPT_SIZE, 457 .help = "Maximum refcount block cache size", 458 }, 459 { 460 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 461 .type = QEMU_OPT_NUMBER, 462 .help = "Clean unused cache entries after this time (in seconds)", 463 }, 464 { /* end of list */ } 465 }, 466 }; 467 468 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 469 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 470 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 471 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 472 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 473 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 474 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 475 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 476 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 477 }; 478 479 static void cache_clean_timer_cb(void *opaque) 480 { 481 BlockDriverState *bs = opaque; 482 BDRVQcow2State *s = bs->opaque; 483 qcow2_cache_clean_unused(bs, s->l2_table_cache); 484 qcow2_cache_clean_unused(bs, s->refcount_block_cache); 485 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 486 (int64_t) s->cache_clean_interval * 1000); 487 } 488 489 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 490 { 491 BDRVQcow2State *s = bs->opaque; 492 if (s->cache_clean_interval > 0) { 493 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 494 SCALE_MS, cache_clean_timer_cb, 495 bs); 496 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 497 (int64_t) s->cache_clean_interval * 1000); 498 } 499 } 500 501 static void cache_clean_timer_del(BlockDriverState *bs) 502 { 503 BDRVQcow2State *s = bs->opaque; 504 if (s->cache_clean_timer) { 505 timer_del(s->cache_clean_timer); 506 timer_free(s->cache_clean_timer); 507 s->cache_clean_timer = NULL; 508 } 509 } 510 511 static void qcow2_detach_aio_context(BlockDriverState *bs) 512 { 513 cache_clean_timer_del(bs); 514 } 515 516 static void qcow2_attach_aio_context(BlockDriverState *bs, 517 AioContext *new_context) 518 { 519 cache_clean_timer_init(bs, new_context); 520 } 521 522 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 523 uint64_t *l2_cache_size, 524 uint64_t *refcount_cache_size, Error **errp) 525 { 526 BDRVQcow2State *s = bs->opaque; 527 uint64_t combined_cache_size; 528 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 529 530 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 531 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 532 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 533 534 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 535 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 536 *refcount_cache_size = qemu_opt_get_size(opts, 537 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 538 539 if (combined_cache_size_set) { 540 if (l2_cache_size_set && refcount_cache_size_set) { 541 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 542 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 543 "the same time"); 544 return; 545 } else if (*l2_cache_size > combined_cache_size) { 546 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 547 QCOW2_OPT_CACHE_SIZE); 548 return; 549 } else if (*refcount_cache_size > combined_cache_size) { 550 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 551 QCOW2_OPT_CACHE_SIZE); 552 return; 553 } 554 555 if (l2_cache_size_set) { 556 *refcount_cache_size = combined_cache_size - *l2_cache_size; 557 } else if (refcount_cache_size_set) { 558 *l2_cache_size = combined_cache_size - *refcount_cache_size; 559 } else { 560 *refcount_cache_size = combined_cache_size 561 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 562 *l2_cache_size = combined_cache_size - *refcount_cache_size; 563 } 564 } else { 565 if (!l2_cache_size_set && !refcount_cache_size_set) { 566 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 567 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 568 * s->cluster_size); 569 *refcount_cache_size = *l2_cache_size 570 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 571 } else if (!l2_cache_size_set) { 572 *l2_cache_size = *refcount_cache_size 573 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 574 } else if (!refcount_cache_size_set) { 575 *refcount_cache_size = *l2_cache_size 576 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 577 } 578 } 579 } 580 581 typedef struct Qcow2ReopenState { 582 Qcow2Cache *l2_table_cache; 583 Qcow2Cache *refcount_block_cache; 584 bool use_lazy_refcounts; 585 int overlap_check; 586 bool discard_passthrough[QCOW2_DISCARD_MAX]; 587 uint64_t cache_clean_interval; 588 } Qcow2ReopenState; 589 590 static int qcow2_update_options_prepare(BlockDriverState *bs, 591 Qcow2ReopenState *r, 592 QDict *options, int flags, 593 Error **errp) 594 { 595 BDRVQcow2State *s = bs->opaque; 596 QemuOpts *opts = NULL; 597 const char *opt_overlap_check, *opt_overlap_check_template; 598 int overlap_check_template = 0; 599 uint64_t l2_cache_size, refcount_cache_size; 600 int i; 601 Error *local_err = NULL; 602 int ret; 603 604 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 605 qemu_opts_absorb_qdict(opts, options, &local_err); 606 if (local_err) { 607 error_propagate(errp, local_err); 608 ret = -EINVAL; 609 goto fail; 610 } 611 612 /* get L2 table/refcount block cache size from command line options */ 613 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 614 &local_err); 615 if (local_err) { 616 error_propagate(errp, local_err); 617 ret = -EINVAL; 618 goto fail; 619 } 620 621 l2_cache_size /= s->cluster_size; 622 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 623 l2_cache_size = MIN_L2_CACHE_SIZE; 624 } 625 if (l2_cache_size > INT_MAX) { 626 error_setg(errp, "L2 cache size too big"); 627 ret = -EINVAL; 628 goto fail; 629 } 630 631 refcount_cache_size /= s->cluster_size; 632 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 633 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 634 } 635 if (refcount_cache_size > INT_MAX) { 636 error_setg(errp, "Refcount cache size too big"); 637 ret = -EINVAL; 638 goto fail; 639 } 640 641 /* alloc new L2 table/refcount block cache, flush old one */ 642 if (s->l2_table_cache) { 643 ret = qcow2_cache_flush(bs, s->l2_table_cache); 644 if (ret) { 645 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 646 goto fail; 647 } 648 } 649 650 if (s->refcount_block_cache) { 651 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 652 if (ret) { 653 error_setg_errno(errp, -ret, 654 "Failed to flush the refcount block cache"); 655 goto fail; 656 } 657 } 658 659 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 660 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 661 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 662 error_setg(errp, "Could not allocate metadata caches"); 663 ret = -ENOMEM; 664 goto fail; 665 } 666 667 /* New interval for cache cleanup timer */ 668 r->cache_clean_interval = 669 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 670 s->cache_clean_interval); 671 if (r->cache_clean_interval > UINT_MAX) { 672 error_setg(errp, "Cache clean interval too big"); 673 ret = -EINVAL; 674 goto fail; 675 } 676 677 /* lazy-refcounts; flush if going from enabled to disabled */ 678 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 679 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 680 if (r->use_lazy_refcounts && s->qcow_version < 3) { 681 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 682 "qemu 1.1 compatibility level"); 683 ret = -EINVAL; 684 goto fail; 685 } 686 687 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 688 ret = qcow2_mark_clean(bs); 689 if (ret < 0) { 690 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 691 goto fail; 692 } 693 } 694 695 /* Overlap check options */ 696 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 697 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 698 if (opt_overlap_check_template && opt_overlap_check && 699 strcmp(opt_overlap_check_template, opt_overlap_check)) 700 { 701 error_setg(errp, "Conflicting values for qcow2 options '" 702 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 703 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 704 ret = -EINVAL; 705 goto fail; 706 } 707 if (!opt_overlap_check) { 708 opt_overlap_check = opt_overlap_check_template ?: "cached"; 709 } 710 711 if (!strcmp(opt_overlap_check, "none")) { 712 overlap_check_template = 0; 713 } else if (!strcmp(opt_overlap_check, "constant")) { 714 overlap_check_template = QCOW2_OL_CONSTANT; 715 } else if (!strcmp(opt_overlap_check, "cached")) { 716 overlap_check_template = QCOW2_OL_CACHED; 717 } else if (!strcmp(opt_overlap_check, "all")) { 718 overlap_check_template = QCOW2_OL_ALL; 719 } else { 720 error_setg(errp, "Unsupported value '%s' for qcow2 option " 721 "'overlap-check'. Allowed are any of the following: " 722 "none, constant, cached, all", opt_overlap_check); 723 ret = -EINVAL; 724 goto fail; 725 } 726 727 r->overlap_check = 0; 728 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 729 /* overlap-check defines a template bitmask, but every flag may be 730 * overwritten through the associated boolean option */ 731 r->overlap_check |= 732 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 733 overlap_check_template & (1 << i)) << i; 734 } 735 736 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 737 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 738 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 739 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 740 flags & BDRV_O_UNMAP); 741 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 742 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 743 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 744 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 745 746 ret = 0; 747 fail: 748 qemu_opts_del(opts); 749 opts = NULL; 750 return ret; 751 } 752 753 static void qcow2_update_options_commit(BlockDriverState *bs, 754 Qcow2ReopenState *r) 755 { 756 BDRVQcow2State *s = bs->opaque; 757 int i; 758 759 if (s->l2_table_cache) { 760 qcow2_cache_destroy(bs, s->l2_table_cache); 761 } 762 if (s->refcount_block_cache) { 763 qcow2_cache_destroy(bs, s->refcount_block_cache); 764 } 765 s->l2_table_cache = r->l2_table_cache; 766 s->refcount_block_cache = r->refcount_block_cache; 767 768 s->overlap_check = r->overlap_check; 769 s->use_lazy_refcounts = r->use_lazy_refcounts; 770 771 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 772 s->discard_passthrough[i] = r->discard_passthrough[i]; 773 } 774 775 if (s->cache_clean_interval != r->cache_clean_interval) { 776 cache_clean_timer_del(bs); 777 s->cache_clean_interval = r->cache_clean_interval; 778 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 779 } 780 } 781 782 static void qcow2_update_options_abort(BlockDriverState *bs, 783 Qcow2ReopenState *r) 784 { 785 if (r->l2_table_cache) { 786 qcow2_cache_destroy(bs, r->l2_table_cache); 787 } 788 if (r->refcount_block_cache) { 789 qcow2_cache_destroy(bs, r->refcount_block_cache); 790 } 791 } 792 793 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 794 int flags, Error **errp) 795 { 796 Qcow2ReopenState r = {}; 797 int ret; 798 799 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 800 if (ret >= 0) { 801 qcow2_update_options_commit(bs, &r); 802 } else { 803 qcow2_update_options_abort(bs, &r); 804 } 805 806 return ret; 807 } 808 809 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 810 Error **errp) 811 { 812 BDRVQcow2State *s = bs->opaque; 813 unsigned int len, i; 814 int ret = 0; 815 QCowHeader header; 816 Error *local_err = NULL; 817 uint64_t ext_end; 818 uint64_t l1_vm_state_index; 819 820 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 821 if (ret < 0) { 822 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 823 goto fail; 824 } 825 be32_to_cpus(&header.magic); 826 be32_to_cpus(&header.version); 827 be64_to_cpus(&header.backing_file_offset); 828 be32_to_cpus(&header.backing_file_size); 829 be64_to_cpus(&header.size); 830 be32_to_cpus(&header.cluster_bits); 831 be32_to_cpus(&header.crypt_method); 832 be64_to_cpus(&header.l1_table_offset); 833 be32_to_cpus(&header.l1_size); 834 be64_to_cpus(&header.refcount_table_offset); 835 be32_to_cpus(&header.refcount_table_clusters); 836 be64_to_cpus(&header.snapshots_offset); 837 be32_to_cpus(&header.nb_snapshots); 838 839 if (header.magic != QCOW_MAGIC) { 840 error_setg(errp, "Image is not in qcow2 format"); 841 ret = -EINVAL; 842 goto fail; 843 } 844 if (header.version < 2 || header.version > 3) { 845 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 846 ret = -ENOTSUP; 847 goto fail; 848 } 849 850 s->qcow_version = header.version; 851 852 /* Initialise cluster size */ 853 if (header.cluster_bits < MIN_CLUSTER_BITS || 854 header.cluster_bits > MAX_CLUSTER_BITS) { 855 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 856 header.cluster_bits); 857 ret = -EINVAL; 858 goto fail; 859 } 860 861 s->cluster_bits = header.cluster_bits; 862 s->cluster_size = 1 << s->cluster_bits; 863 s->cluster_sectors = 1 << (s->cluster_bits - 9); 864 865 /* Initialise version 3 header fields */ 866 if (header.version == 2) { 867 header.incompatible_features = 0; 868 header.compatible_features = 0; 869 header.autoclear_features = 0; 870 header.refcount_order = 4; 871 header.header_length = 72; 872 } else { 873 be64_to_cpus(&header.incompatible_features); 874 be64_to_cpus(&header.compatible_features); 875 be64_to_cpus(&header.autoclear_features); 876 be32_to_cpus(&header.refcount_order); 877 be32_to_cpus(&header.header_length); 878 879 if (header.header_length < 104) { 880 error_setg(errp, "qcow2 header too short"); 881 ret = -EINVAL; 882 goto fail; 883 } 884 } 885 886 if (header.header_length > s->cluster_size) { 887 error_setg(errp, "qcow2 header exceeds cluster size"); 888 ret = -EINVAL; 889 goto fail; 890 } 891 892 if (header.header_length > sizeof(header)) { 893 s->unknown_header_fields_size = header.header_length - sizeof(header); 894 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 895 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 896 s->unknown_header_fields_size); 897 if (ret < 0) { 898 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 899 "fields"); 900 goto fail; 901 } 902 } 903 904 if (header.backing_file_offset > s->cluster_size) { 905 error_setg(errp, "Invalid backing file offset"); 906 ret = -EINVAL; 907 goto fail; 908 } 909 910 if (header.backing_file_offset) { 911 ext_end = header.backing_file_offset; 912 } else { 913 ext_end = 1 << header.cluster_bits; 914 } 915 916 /* Handle feature bits */ 917 s->incompatible_features = header.incompatible_features; 918 s->compatible_features = header.compatible_features; 919 s->autoclear_features = header.autoclear_features; 920 921 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 922 void *feature_table = NULL; 923 qcow2_read_extensions(bs, header.header_length, ext_end, 924 &feature_table, NULL); 925 report_unsupported_feature(errp, feature_table, 926 s->incompatible_features & 927 ~QCOW2_INCOMPAT_MASK); 928 ret = -ENOTSUP; 929 g_free(feature_table); 930 goto fail; 931 } 932 933 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 934 /* Corrupt images may not be written to unless they are being repaired 935 */ 936 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 937 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 938 "read/write"); 939 ret = -EACCES; 940 goto fail; 941 } 942 } 943 944 /* Check support for various header values */ 945 if (header.refcount_order > 6) { 946 error_setg(errp, "Reference count entry width too large; may not " 947 "exceed 64 bits"); 948 ret = -EINVAL; 949 goto fail; 950 } 951 s->refcount_order = header.refcount_order; 952 s->refcount_bits = 1 << s->refcount_order; 953 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 954 s->refcount_max += s->refcount_max - 1; 955 956 if (header.crypt_method > QCOW_CRYPT_AES) { 957 error_setg(errp, "Unsupported encryption method: %" PRIu32, 958 header.crypt_method); 959 ret = -EINVAL; 960 goto fail; 961 } 962 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 963 error_setg(errp, "AES cipher not available"); 964 ret = -EINVAL; 965 goto fail; 966 } 967 s->crypt_method_header = header.crypt_method; 968 if (s->crypt_method_header) { 969 if (bdrv_uses_whitelist() && 970 s->crypt_method_header == QCOW_CRYPT_AES) { 971 error_setg(errp, 972 "Use of AES-CBC encrypted qcow2 images is no longer " 973 "supported in system emulators"); 974 error_append_hint(errp, 975 "You can use 'qemu-img convert' to convert your " 976 "image to an alternative supported format, such " 977 "as unencrypted qcow2, or raw with the LUKS " 978 "format instead.\n"); 979 ret = -ENOSYS; 980 goto fail; 981 } 982 983 bs->encrypted = true; 984 } 985 986 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 987 s->l2_size = 1 << s->l2_bits; 988 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 989 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 990 s->refcount_block_size = 1 << s->refcount_block_bits; 991 bs->total_sectors = header.size / 512; 992 s->csize_shift = (62 - (s->cluster_bits - 8)); 993 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 994 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 995 996 s->refcount_table_offset = header.refcount_table_offset; 997 s->refcount_table_size = 998 header.refcount_table_clusters << (s->cluster_bits - 3); 999 1000 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 1001 error_setg(errp, "Reference count table too large"); 1002 ret = -EINVAL; 1003 goto fail; 1004 } 1005 1006 ret = validate_table_offset(bs, s->refcount_table_offset, 1007 s->refcount_table_size, sizeof(uint64_t)); 1008 if (ret < 0) { 1009 error_setg(errp, "Invalid reference count table offset"); 1010 goto fail; 1011 } 1012 1013 /* Snapshot table offset/length */ 1014 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1015 error_setg(errp, "Too many snapshots"); 1016 ret = -EINVAL; 1017 goto fail; 1018 } 1019 1020 ret = validate_table_offset(bs, header.snapshots_offset, 1021 header.nb_snapshots, 1022 sizeof(QCowSnapshotHeader)); 1023 if (ret < 0) { 1024 error_setg(errp, "Invalid snapshot table offset"); 1025 goto fail; 1026 } 1027 1028 /* read the level 1 table */ 1029 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1030 error_setg(errp, "Active L1 table too large"); 1031 ret = -EFBIG; 1032 goto fail; 1033 } 1034 s->l1_size = header.l1_size; 1035 1036 l1_vm_state_index = size_to_l1(s, header.size); 1037 if (l1_vm_state_index > INT_MAX) { 1038 error_setg(errp, "Image is too big"); 1039 ret = -EFBIG; 1040 goto fail; 1041 } 1042 s->l1_vm_state_index = l1_vm_state_index; 1043 1044 /* the L1 table must contain at least enough entries to put 1045 header.size bytes */ 1046 if (s->l1_size < s->l1_vm_state_index) { 1047 error_setg(errp, "L1 table is too small"); 1048 ret = -EINVAL; 1049 goto fail; 1050 } 1051 1052 ret = validate_table_offset(bs, header.l1_table_offset, 1053 header.l1_size, sizeof(uint64_t)); 1054 if (ret < 0) { 1055 error_setg(errp, "Invalid L1 table offset"); 1056 goto fail; 1057 } 1058 s->l1_table_offset = header.l1_table_offset; 1059 1060 1061 if (s->l1_size > 0) { 1062 s->l1_table = qemu_try_blockalign(bs->file->bs, 1063 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1064 if (s->l1_table == NULL) { 1065 error_setg(errp, "Could not allocate L1 table"); 1066 ret = -ENOMEM; 1067 goto fail; 1068 } 1069 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1070 s->l1_size * sizeof(uint64_t)); 1071 if (ret < 0) { 1072 error_setg_errno(errp, -ret, "Could not read L1 table"); 1073 goto fail; 1074 } 1075 for(i = 0;i < s->l1_size; i++) { 1076 be64_to_cpus(&s->l1_table[i]); 1077 } 1078 } 1079 1080 /* Parse driver-specific options */ 1081 ret = qcow2_update_options(bs, options, flags, errp); 1082 if (ret < 0) { 1083 goto fail; 1084 } 1085 1086 s->cluster_cache = g_malloc(s->cluster_size); 1087 /* one more sector for decompressed data alignment */ 1088 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1089 * s->cluster_size + 512); 1090 if (s->cluster_data == NULL) { 1091 error_setg(errp, "Could not allocate temporary cluster buffer"); 1092 ret = -ENOMEM; 1093 goto fail; 1094 } 1095 1096 s->cluster_cache_offset = -1; 1097 s->flags = flags; 1098 1099 ret = qcow2_refcount_init(bs); 1100 if (ret != 0) { 1101 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1102 goto fail; 1103 } 1104 1105 QLIST_INIT(&s->cluster_allocs); 1106 QTAILQ_INIT(&s->discards); 1107 1108 /* read qcow2 extensions */ 1109 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1110 &local_err)) { 1111 error_propagate(errp, local_err); 1112 ret = -EINVAL; 1113 goto fail; 1114 } 1115 1116 /* read the backing file name */ 1117 if (header.backing_file_offset != 0) { 1118 len = header.backing_file_size; 1119 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1120 len >= sizeof(bs->backing_file)) { 1121 error_setg(errp, "Backing file name too long"); 1122 ret = -EINVAL; 1123 goto fail; 1124 } 1125 ret = bdrv_pread(bs->file, header.backing_file_offset, 1126 bs->backing_file, len); 1127 if (ret < 0) { 1128 error_setg_errno(errp, -ret, "Could not read backing file name"); 1129 goto fail; 1130 } 1131 bs->backing_file[len] = '\0'; 1132 s->image_backing_file = g_strdup(bs->backing_file); 1133 } 1134 1135 /* Internal snapshots */ 1136 s->snapshots_offset = header.snapshots_offset; 1137 s->nb_snapshots = header.nb_snapshots; 1138 1139 ret = qcow2_read_snapshots(bs); 1140 if (ret < 0) { 1141 error_setg_errno(errp, -ret, "Could not read snapshots"); 1142 goto fail; 1143 } 1144 1145 /* Clear unknown autoclear feature bits */ 1146 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { 1147 s->autoclear_features = 0; 1148 ret = qcow2_update_header(bs); 1149 if (ret < 0) { 1150 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1151 goto fail; 1152 } 1153 } 1154 1155 /* Initialise locks */ 1156 qemu_co_mutex_init(&s->lock); 1157 1158 /* Repair image if dirty */ 1159 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1160 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1161 BdrvCheckResult result = {0}; 1162 1163 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1164 if (ret < 0) { 1165 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1166 goto fail; 1167 } 1168 } 1169 1170 #ifdef DEBUG_ALLOC 1171 { 1172 BdrvCheckResult result = {0}; 1173 qcow2_check_refcounts(bs, &result, 0); 1174 } 1175 #endif 1176 return ret; 1177 1178 fail: 1179 g_free(s->unknown_header_fields); 1180 cleanup_unknown_header_ext(bs); 1181 qcow2_free_snapshots(bs); 1182 qcow2_refcount_close(bs); 1183 qemu_vfree(s->l1_table); 1184 /* else pre-write overlap checks in cache_destroy may crash */ 1185 s->l1_table = NULL; 1186 cache_clean_timer_del(bs); 1187 if (s->l2_table_cache) { 1188 qcow2_cache_destroy(bs, s->l2_table_cache); 1189 } 1190 if (s->refcount_block_cache) { 1191 qcow2_cache_destroy(bs, s->refcount_block_cache); 1192 } 1193 g_free(s->cluster_cache); 1194 qemu_vfree(s->cluster_data); 1195 return ret; 1196 } 1197 1198 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1199 { 1200 BDRVQcow2State *s = bs->opaque; 1201 1202 if (bs->encrypted) { 1203 /* Encryption works on a sector granularity */ 1204 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 1205 } 1206 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1207 } 1208 1209 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1210 { 1211 BDRVQcow2State *s = bs->opaque; 1212 uint8_t keybuf[16]; 1213 int len, i; 1214 Error *err = NULL; 1215 1216 memset(keybuf, 0, 16); 1217 len = strlen(key); 1218 if (len > 16) 1219 len = 16; 1220 /* XXX: we could compress the chars to 7 bits to increase 1221 entropy */ 1222 for(i = 0;i < len;i++) { 1223 keybuf[i] = key[i]; 1224 } 1225 assert(bs->encrypted); 1226 1227 qcrypto_cipher_free(s->cipher); 1228 s->cipher = qcrypto_cipher_new( 1229 QCRYPTO_CIPHER_ALG_AES_128, 1230 QCRYPTO_CIPHER_MODE_CBC, 1231 keybuf, G_N_ELEMENTS(keybuf), 1232 &err); 1233 1234 if (!s->cipher) { 1235 /* XXX would be nice if errors in this method could 1236 * be properly propagate to the caller. Would need 1237 * the bdrv_set_key() API signature to be fixed. */ 1238 error_free(err); 1239 return -1; 1240 } 1241 return 0; 1242 } 1243 1244 static int qcow2_reopen_prepare(BDRVReopenState *state, 1245 BlockReopenQueue *queue, Error **errp) 1246 { 1247 Qcow2ReopenState *r; 1248 int ret; 1249 1250 r = g_new0(Qcow2ReopenState, 1); 1251 state->opaque = r; 1252 1253 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1254 state->flags, errp); 1255 if (ret < 0) { 1256 goto fail; 1257 } 1258 1259 /* We need to write out any unwritten data if we reopen read-only. */ 1260 if ((state->flags & BDRV_O_RDWR) == 0) { 1261 ret = bdrv_flush(state->bs); 1262 if (ret < 0) { 1263 goto fail; 1264 } 1265 1266 ret = qcow2_mark_clean(state->bs); 1267 if (ret < 0) { 1268 goto fail; 1269 } 1270 } 1271 1272 return 0; 1273 1274 fail: 1275 qcow2_update_options_abort(state->bs, r); 1276 g_free(r); 1277 return ret; 1278 } 1279 1280 static void qcow2_reopen_commit(BDRVReopenState *state) 1281 { 1282 qcow2_update_options_commit(state->bs, state->opaque); 1283 g_free(state->opaque); 1284 } 1285 1286 static void qcow2_reopen_abort(BDRVReopenState *state) 1287 { 1288 qcow2_update_options_abort(state->bs, state->opaque); 1289 g_free(state->opaque); 1290 } 1291 1292 static void qcow2_join_options(QDict *options, QDict *old_options) 1293 { 1294 bool has_new_overlap_template = 1295 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1296 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1297 bool has_new_total_cache_size = 1298 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1299 bool has_all_cache_options; 1300 1301 /* New overlap template overrides all old overlap options */ 1302 if (has_new_overlap_template) { 1303 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1304 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1305 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1306 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1307 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1308 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1309 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1310 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1311 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1312 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1313 } 1314 1315 /* New total cache size overrides all old options */ 1316 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1317 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1318 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1319 } 1320 1321 qdict_join(options, old_options, false); 1322 1323 /* 1324 * If after merging all cache size options are set, an old total size is 1325 * overwritten. Do keep all options, however, if all three are new. The 1326 * resulting error message is what we want to happen. 1327 */ 1328 has_all_cache_options = 1329 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1330 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1331 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1332 1333 if (has_all_cache_options && !has_new_total_cache_size) { 1334 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1335 } 1336 } 1337 1338 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1339 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1340 { 1341 BDRVQcow2State *s = bs->opaque; 1342 uint64_t cluster_offset; 1343 int index_in_cluster, ret; 1344 unsigned int bytes; 1345 int64_t status = 0; 1346 1347 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE); 1348 qemu_co_mutex_lock(&s->lock); 1349 ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes, 1350 &cluster_offset); 1351 qemu_co_mutex_unlock(&s->lock); 1352 if (ret < 0) { 1353 return ret; 1354 } 1355 1356 *pnum = bytes >> BDRV_SECTOR_BITS; 1357 1358 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1359 !s->cipher) { 1360 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1361 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1362 *file = bs->file->bs; 1363 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1364 } 1365 if (ret == QCOW2_CLUSTER_ZERO) { 1366 status |= BDRV_BLOCK_ZERO; 1367 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1368 status |= BDRV_BLOCK_DATA; 1369 } 1370 return status; 1371 } 1372 1373 /* handle reading after the end of the backing file */ 1374 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1375 int64_t offset, int bytes) 1376 { 1377 uint64_t bs_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1378 int n1; 1379 1380 if ((offset + bytes) <= bs_size) { 1381 return bytes; 1382 } 1383 1384 if (offset >= bs_size) { 1385 n1 = 0; 1386 } else { 1387 n1 = bs_size - offset; 1388 } 1389 1390 qemu_iovec_memset(qiov, n1, 0, bytes - n1); 1391 1392 return n1; 1393 } 1394 1395 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1396 uint64_t bytes, QEMUIOVector *qiov, 1397 int flags) 1398 { 1399 BDRVQcow2State *s = bs->opaque; 1400 int offset_in_cluster, n1; 1401 int ret; 1402 unsigned int cur_bytes; /* number of bytes in current iteration */ 1403 uint64_t cluster_offset = 0; 1404 uint64_t bytes_done = 0; 1405 QEMUIOVector hd_qiov; 1406 uint8_t *cluster_data = NULL; 1407 1408 qemu_iovec_init(&hd_qiov, qiov->niov); 1409 1410 qemu_co_mutex_lock(&s->lock); 1411 1412 while (bytes != 0) { 1413 1414 /* prepare next request */ 1415 cur_bytes = MIN(bytes, INT_MAX); 1416 if (s->cipher) { 1417 cur_bytes = MIN(cur_bytes, 1418 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1419 } 1420 1421 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1422 if (ret < 0) { 1423 goto fail; 1424 } 1425 1426 offset_in_cluster = offset_into_cluster(s, offset); 1427 1428 qemu_iovec_reset(&hd_qiov); 1429 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1430 1431 switch (ret) { 1432 case QCOW2_CLUSTER_UNALLOCATED: 1433 1434 if (bs->backing) { 1435 /* read from the base image */ 1436 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1437 offset, cur_bytes); 1438 if (n1 > 0) { 1439 QEMUIOVector local_qiov; 1440 1441 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1442 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1); 1443 1444 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1445 qemu_co_mutex_unlock(&s->lock); 1446 ret = bdrv_co_preadv(bs->backing, offset, n1, 1447 &local_qiov, 0); 1448 qemu_co_mutex_lock(&s->lock); 1449 1450 qemu_iovec_destroy(&local_qiov); 1451 1452 if (ret < 0) { 1453 goto fail; 1454 } 1455 } 1456 } else { 1457 /* Note: in this case, no need to wait */ 1458 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1459 } 1460 break; 1461 1462 case QCOW2_CLUSTER_ZERO: 1463 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1464 break; 1465 1466 case QCOW2_CLUSTER_COMPRESSED: 1467 /* add AIO support for compressed blocks ? */ 1468 ret = qcow2_decompress_cluster(bs, cluster_offset); 1469 if (ret < 0) { 1470 goto fail; 1471 } 1472 1473 qemu_iovec_from_buf(&hd_qiov, 0, 1474 s->cluster_cache + offset_in_cluster, 1475 cur_bytes); 1476 break; 1477 1478 case QCOW2_CLUSTER_NORMAL: 1479 if ((cluster_offset & 511) != 0) { 1480 ret = -EIO; 1481 goto fail; 1482 } 1483 1484 if (bs->encrypted) { 1485 assert(s->cipher); 1486 1487 /* 1488 * For encrypted images, read everything into a temporary 1489 * contiguous buffer on which the AES functions can work. 1490 */ 1491 if (!cluster_data) { 1492 cluster_data = 1493 qemu_try_blockalign(bs->file->bs, 1494 QCOW_MAX_CRYPT_CLUSTERS 1495 * s->cluster_size); 1496 if (cluster_data == NULL) { 1497 ret = -ENOMEM; 1498 goto fail; 1499 } 1500 } 1501 1502 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1503 qemu_iovec_reset(&hd_qiov); 1504 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1505 } 1506 1507 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1508 qemu_co_mutex_unlock(&s->lock); 1509 ret = bdrv_co_preadv(bs->file, 1510 cluster_offset + offset_in_cluster, 1511 cur_bytes, &hd_qiov, 0); 1512 qemu_co_mutex_lock(&s->lock); 1513 if (ret < 0) { 1514 goto fail; 1515 } 1516 if (bs->encrypted) { 1517 assert(s->cipher); 1518 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1519 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1520 Error *err = NULL; 1521 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS, 1522 cluster_data, cluster_data, 1523 cur_bytes >> BDRV_SECTOR_BITS, 1524 false, &err) < 0) { 1525 error_free(err); 1526 ret = -EIO; 1527 goto fail; 1528 } 1529 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1530 } 1531 break; 1532 1533 default: 1534 g_assert_not_reached(); 1535 ret = -EIO; 1536 goto fail; 1537 } 1538 1539 bytes -= cur_bytes; 1540 offset += cur_bytes; 1541 bytes_done += cur_bytes; 1542 } 1543 ret = 0; 1544 1545 fail: 1546 qemu_co_mutex_unlock(&s->lock); 1547 1548 qemu_iovec_destroy(&hd_qiov); 1549 qemu_vfree(cluster_data); 1550 1551 return ret; 1552 } 1553 1554 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 1555 uint64_t bytes, QEMUIOVector *qiov, 1556 int flags) 1557 { 1558 BDRVQcow2State *s = bs->opaque; 1559 int offset_in_cluster; 1560 int ret; 1561 unsigned int cur_bytes; /* number of sectors in current iteration */ 1562 uint64_t cluster_offset; 1563 QEMUIOVector hd_qiov; 1564 uint64_t bytes_done = 0; 1565 uint8_t *cluster_data = NULL; 1566 QCowL2Meta *l2meta = NULL; 1567 1568 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 1569 1570 qemu_iovec_init(&hd_qiov, qiov->niov); 1571 1572 s->cluster_cache_offset = -1; /* disable compressed cache */ 1573 1574 qemu_co_mutex_lock(&s->lock); 1575 1576 while (bytes != 0) { 1577 1578 l2meta = NULL; 1579 1580 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1581 offset_in_cluster = offset_into_cluster(s, offset); 1582 cur_bytes = MIN(bytes, INT_MAX); 1583 if (bs->encrypted) { 1584 cur_bytes = MIN(cur_bytes, 1585 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 1586 - offset_in_cluster); 1587 } 1588 1589 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 1590 &cluster_offset, &l2meta); 1591 if (ret < 0) { 1592 goto fail; 1593 } 1594 1595 assert((cluster_offset & 511) == 0); 1596 1597 qemu_iovec_reset(&hd_qiov); 1598 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1599 1600 if (bs->encrypted) { 1601 Error *err = NULL; 1602 assert(s->cipher); 1603 if (!cluster_data) { 1604 cluster_data = qemu_try_blockalign(bs->file->bs, 1605 QCOW_MAX_CRYPT_CLUSTERS 1606 * s->cluster_size); 1607 if (cluster_data == NULL) { 1608 ret = -ENOMEM; 1609 goto fail; 1610 } 1611 } 1612 1613 assert(hd_qiov.size <= 1614 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1615 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1616 1617 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS, 1618 cluster_data, cluster_data, 1619 cur_bytes >>BDRV_SECTOR_BITS, 1620 true, &err) < 0) { 1621 error_free(err); 1622 ret = -EIO; 1623 goto fail; 1624 } 1625 1626 qemu_iovec_reset(&hd_qiov); 1627 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1628 } 1629 1630 ret = qcow2_pre_write_overlap_check(bs, 0, 1631 cluster_offset + offset_in_cluster, cur_bytes); 1632 if (ret < 0) { 1633 goto fail; 1634 } 1635 1636 qemu_co_mutex_unlock(&s->lock); 1637 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1638 trace_qcow2_writev_data(qemu_coroutine_self(), 1639 cluster_offset + offset_in_cluster); 1640 ret = bdrv_co_pwritev(bs->file, 1641 cluster_offset + offset_in_cluster, 1642 cur_bytes, &hd_qiov, 0); 1643 qemu_co_mutex_lock(&s->lock); 1644 if (ret < 0) { 1645 goto fail; 1646 } 1647 1648 while (l2meta != NULL) { 1649 QCowL2Meta *next; 1650 1651 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1652 if (ret < 0) { 1653 goto fail; 1654 } 1655 1656 /* Take the request off the list of running requests */ 1657 if (l2meta->nb_clusters != 0) { 1658 QLIST_REMOVE(l2meta, next_in_flight); 1659 } 1660 1661 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1662 1663 next = l2meta->next; 1664 g_free(l2meta); 1665 l2meta = next; 1666 } 1667 1668 bytes -= cur_bytes; 1669 offset += cur_bytes; 1670 bytes_done += cur_bytes; 1671 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 1672 } 1673 ret = 0; 1674 1675 fail: 1676 qemu_co_mutex_unlock(&s->lock); 1677 1678 while (l2meta != NULL) { 1679 QCowL2Meta *next; 1680 1681 if (l2meta->nb_clusters != 0) { 1682 QLIST_REMOVE(l2meta, next_in_flight); 1683 } 1684 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1685 1686 next = l2meta->next; 1687 g_free(l2meta); 1688 l2meta = next; 1689 } 1690 1691 qemu_iovec_destroy(&hd_qiov); 1692 qemu_vfree(cluster_data); 1693 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1694 1695 return ret; 1696 } 1697 1698 static int qcow2_inactivate(BlockDriverState *bs) 1699 { 1700 BDRVQcow2State *s = bs->opaque; 1701 int ret, result = 0; 1702 1703 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1704 if (ret) { 1705 result = ret; 1706 error_report("Failed to flush the L2 table cache: %s", 1707 strerror(-ret)); 1708 } 1709 1710 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1711 if (ret) { 1712 result = ret; 1713 error_report("Failed to flush the refcount block cache: %s", 1714 strerror(-ret)); 1715 } 1716 1717 if (result == 0) { 1718 qcow2_mark_clean(bs); 1719 } 1720 1721 return result; 1722 } 1723 1724 static void qcow2_close(BlockDriverState *bs) 1725 { 1726 BDRVQcow2State *s = bs->opaque; 1727 qemu_vfree(s->l1_table); 1728 /* else pre-write overlap checks in cache_destroy may crash */ 1729 s->l1_table = NULL; 1730 1731 if (!(s->flags & BDRV_O_INACTIVE)) { 1732 qcow2_inactivate(bs); 1733 } 1734 1735 cache_clean_timer_del(bs); 1736 qcow2_cache_destroy(bs, s->l2_table_cache); 1737 qcow2_cache_destroy(bs, s->refcount_block_cache); 1738 1739 qcrypto_cipher_free(s->cipher); 1740 s->cipher = NULL; 1741 1742 g_free(s->unknown_header_fields); 1743 cleanup_unknown_header_ext(bs); 1744 1745 g_free(s->image_backing_file); 1746 g_free(s->image_backing_format); 1747 1748 g_free(s->cluster_cache); 1749 qemu_vfree(s->cluster_data); 1750 qcow2_refcount_close(bs); 1751 qcow2_free_snapshots(bs); 1752 } 1753 1754 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1755 { 1756 BDRVQcow2State *s = bs->opaque; 1757 int flags = s->flags; 1758 QCryptoCipher *cipher = NULL; 1759 QDict *options; 1760 Error *local_err = NULL; 1761 int ret; 1762 1763 /* 1764 * Backing files are read-only which makes all of their metadata immutable, 1765 * that means we don't have to worry about reopening them here. 1766 */ 1767 1768 cipher = s->cipher; 1769 s->cipher = NULL; 1770 1771 qcow2_close(bs); 1772 1773 memset(s, 0, sizeof(BDRVQcow2State)); 1774 options = qdict_clone_shallow(bs->options); 1775 1776 flags &= ~BDRV_O_INACTIVE; 1777 ret = qcow2_open(bs, options, flags, &local_err); 1778 QDECREF(options); 1779 if (local_err) { 1780 error_propagate(errp, local_err); 1781 error_prepend(errp, "Could not reopen qcow2 layer: "); 1782 bs->drv = NULL; 1783 return; 1784 } else if (ret < 0) { 1785 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1786 bs->drv = NULL; 1787 return; 1788 } 1789 1790 s->cipher = cipher; 1791 } 1792 1793 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1794 size_t len, size_t buflen) 1795 { 1796 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1797 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1798 1799 if (buflen < ext_len) { 1800 return -ENOSPC; 1801 } 1802 1803 *ext_backing_fmt = (QCowExtension) { 1804 .magic = cpu_to_be32(magic), 1805 .len = cpu_to_be32(len), 1806 }; 1807 memcpy(buf + sizeof(QCowExtension), s, len); 1808 1809 return ext_len; 1810 } 1811 1812 /* 1813 * Updates the qcow2 header, including the variable length parts of it, i.e. 1814 * the backing file name and all extensions. qcow2 was not designed to allow 1815 * such changes, so if we run out of space (we can only use the first cluster) 1816 * this function may fail. 1817 * 1818 * Returns 0 on success, -errno in error cases. 1819 */ 1820 int qcow2_update_header(BlockDriverState *bs) 1821 { 1822 BDRVQcow2State *s = bs->opaque; 1823 QCowHeader *header; 1824 char *buf; 1825 size_t buflen = s->cluster_size; 1826 int ret; 1827 uint64_t total_size; 1828 uint32_t refcount_table_clusters; 1829 size_t header_length; 1830 Qcow2UnknownHeaderExtension *uext; 1831 1832 buf = qemu_blockalign(bs, buflen); 1833 1834 /* Header structure */ 1835 header = (QCowHeader*) buf; 1836 1837 if (buflen < sizeof(*header)) { 1838 ret = -ENOSPC; 1839 goto fail; 1840 } 1841 1842 header_length = sizeof(*header) + s->unknown_header_fields_size; 1843 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1844 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1845 1846 *header = (QCowHeader) { 1847 /* Version 2 fields */ 1848 .magic = cpu_to_be32(QCOW_MAGIC), 1849 .version = cpu_to_be32(s->qcow_version), 1850 .backing_file_offset = 0, 1851 .backing_file_size = 0, 1852 .cluster_bits = cpu_to_be32(s->cluster_bits), 1853 .size = cpu_to_be64(total_size), 1854 .crypt_method = cpu_to_be32(s->crypt_method_header), 1855 .l1_size = cpu_to_be32(s->l1_size), 1856 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1857 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1858 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1859 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1860 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1861 1862 /* Version 3 fields */ 1863 .incompatible_features = cpu_to_be64(s->incompatible_features), 1864 .compatible_features = cpu_to_be64(s->compatible_features), 1865 .autoclear_features = cpu_to_be64(s->autoclear_features), 1866 .refcount_order = cpu_to_be32(s->refcount_order), 1867 .header_length = cpu_to_be32(header_length), 1868 }; 1869 1870 /* For older versions, write a shorter header */ 1871 switch (s->qcow_version) { 1872 case 2: 1873 ret = offsetof(QCowHeader, incompatible_features); 1874 break; 1875 case 3: 1876 ret = sizeof(*header); 1877 break; 1878 default: 1879 ret = -EINVAL; 1880 goto fail; 1881 } 1882 1883 buf += ret; 1884 buflen -= ret; 1885 memset(buf, 0, buflen); 1886 1887 /* Preserve any unknown field in the header */ 1888 if (s->unknown_header_fields_size) { 1889 if (buflen < s->unknown_header_fields_size) { 1890 ret = -ENOSPC; 1891 goto fail; 1892 } 1893 1894 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1895 buf += s->unknown_header_fields_size; 1896 buflen -= s->unknown_header_fields_size; 1897 } 1898 1899 /* Backing file format header extension */ 1900 if (s->image_backing_format) { 1901 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1902 s->image_backing_format, 1903 strlen(s->image_backing_format), 1904 buflen); 1905 if (ret < 0) { 1906 goto fail; 1907 } 1908 1909 buf += ret; 1910 buflen -= ret; 1911 } 1912 1913 /* Feature table */ 1914 if (s->qcow_version >= 3) { 1915 Qcow2Feature features[] = { 1916 { 1917 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1918 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1919 .name = "dirty bit", 1920 }, 1921 { 1922 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1923 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1924 .name = "corrupt bit", 1925 }, 1926 { 1927 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1928 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1929 .name = "lazy refcounts", 1930 }, 1931 }; 1932 1933 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1934 features, sizeof(features), buflen); 1935 if (ret < 0) { 1936 goto fail; 1937 } 1938 buf += ret; 1939 buflen -= ret; 1940 } 1941 1942 /* Keep unknown header extensions */ 1943 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1944 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1945 if (ret < 0) { 1946 goto fail; 1947 } 1948 1949 buf += ret; 1950 buflen -= ret; 1951 } 1952 1953 /* End of header extensions */ 1954 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1955 if (ret < 0) { 1956 goto fail; 1957 } 1958 1959 buf += ret; 1960 buflen -= ret; 1961 1962 /* Backing file name */ 1963 if (s->image_backing_file) { 1964 size_t backing_file_len = strlen(s->image_backing_file); 1965 1966 if (buflen < backing_file_len) { 1967 ret = -ENOSPC; 1968 goto fail; 1969 } 1970 1971 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1972 strncpy(buf, s->image_backing_file, buflen); 1973 1974 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 1975 header->backing_file_size = cpu_to_be32(backing_file_len); 1976 } 1977 1978 /* Write the new header */ 1979 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 1980 if (ret < 0) { 1981 goto fail; 1982 } 1983 1984 ret = 0; 1985 fail: 1986 qemu_vfree(header); 1987 return ret; 1988 } 1989 1990 static int qcow2_change_backing_file(BlockDriverState *bs, 1991 const char *backing_file, const char *backing_fmt) 1992 { 1993 BDRVQcow2State *s = bs->opaque; 1994 1995 if (backing_file && strlen(backing_file) > 1023) { 1996 return -EINVAL; 1997 } 1998 1999 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2000 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2001 2002 g_free(s->image_backing_file); 2003 g_free(s->image_backing_format); 2004 2005 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2006 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2007 2008 return qcow2_update_header(bs); 2009 } 2010 2011 static int preallocate(BlockDriverState *bs) 2012 { 2013 uint64_t bytes; 2014 uint64_t offset; 2015 uint64_t host_offset = 0; 2016 unsigned int cur_bytes; 2017 int ret; 2018 QCowL2Meta *meta; 2019 2020 bytes = bdrv_getlength(bs); 2021 offset = 0; 2022 2023 while (bytes) { 2024 cur_bytes = MIN(bytes, INT_MAX); 2025 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2026 &host_offset, &meta); 2027 if (ret < 0) { 2028 return ret; 2029 } 2030 2031 while (meta) { 2032 QCowL2Meta *next = meta->next; 2033 2034 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2035 if (ret < 0) { 2036 qcow2_free_any_clusters(bs, meta->alloc_offset, 2037 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2038 return ret; 2039 } 2040 2041 /* There are no dependent requests, but we need to remove our 2042 * request from the list of in-flight requests */ 2043 QLIST_REMOVE(meta, next_in_flight); 2044 2045 g_free(meta); 2046 meta = next; 2047 } 2048 2049 /* TODO Preallocate data if requested */ 2050 2051 bytes -= cur_bytes; 2052 offset += cur_bytes; 2053 } 2054 2055 /* 2056 * It is expected that the image file is large enough to actually contain 2057 * all of the allocated clusters (otherwise we get failing reads after 2058 * EOF). Extend the image to the last allocated sector. 2059 */ 2060 if (host_offset != 0) { 2061 uint8_t data = 0; 2062 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2063 &data, 1); 2064 if (ret < 0) { 2065 return ret; 2066 } 2067 } 2068 2069 return 0; 2070 } 2071 2072 static int qcow2_create2(const char *filename, int64_t total_size, 2073 const char *backing_file, const char *backing_format, 2074 int flags, size_t cluster_size, PreallocMode prealloc, 2075 QemuOpts *opts, int version, int refcount_order, 2076 Error **errp) 2077 { 2078 int cluster_bits; 2079 QDict *options; 2080 2081 /* Calculate cluster_bits */ 2082 cluster_bits = ctz32(cluster_size); 2083 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2084 (1 << cluster_bits) != cluster_size) 2085 { 2086 error_setg(errp, "Cluster size must be a power of two between %d and " 2087 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2088 return -EINVAL; 2089 } 2090 2091 /* 2092 * Open the image file and write a minimal qcow2 header. 2093 * 2094 * We keep things simple and start with a zero-sized image. We also 2095 * do without refcount blocks or a L1 table for now. We'll fix the 2096 * inconsistency later. 2097 * 2098 * We do need a refcount table because growing the refcount table means 2099 * allocating two new refcount blocks - the seconds of which would be at 2100 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2101 * size for any qcow2 image. 2102 */ 2103 BlockBackend *blk; 2104 QCowHeader *header; 2105 uint64_t* refcount_table; 2106 Error *local_err = NULL; 2107 int ret; 2108 2109 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2110 /* Note: The following calculation does not need to be exact; if it is a 2111 * bit off, either some bytes will be "leaked" (which is fine) or we 2112 * will need to increase the file size by some bytes (which is fine, 2113 * too, as long as the bulk is allocated here). Therefore, using 2114 * floating point arithmetic is fine. */ 2115 int64_t meta_size = 0; 2116 uint64_t nreftablee, nrefblocke, nl1e, nl2e; 2117 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2118 int refblock_bits, refblock_size; 2119 /* refcount entry size in bytes */ 2120 double rces = (1 << refcount_order) / 8.; 2121 2122 /* see qcow2_open() */ 2123 refblock_bits = cluster_bits - (refcount_order - 3); 2124 refblock_size = 1 << refblock_bits; 2125 2126 /* header: 1 cluster */ 2127 meta_size += cluster_size; 2128 2129 /* total size of L2 tables */ 2130 nl2e = aligned_total_size / cluster_size; 2131 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2132 meta_size += nl2e * sizeof(uint64_t); 2133 2134 /* total size of L1 tables */ 2135 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2136 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2137 meta_size += nl1e * sizeof(uint64_t); 2138 2139 /* total size of refcount blocks 2140 * 2141 * note: every host cluster is reference-counted, including metadata 2142 * (even refcount blocks are recursively included). 2143 * Let: 2144 * a = total_size (this is the guest disk size) 2145 * m = meta size not including refcount blocks and refcount tables 2146 * c = cluster size 2147 * y1 = number of refcount blocks entries 2148 * y2 = meta size including everything 2149 * rces = refcount entry size in bytes 2150 * then, 2151 * y1 = (y2 + a)/c 2152 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2153 * we can get y1: 2154 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2155 */ 2156 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2157 / (cluster_size - rces - rces * sizeof(uint64_t) 2158 / cluster_size); 2159 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size; 2160 2161 /* total size of refcount tables */ 2162 nreftablee = nrefblocke / refblock_size; 2163 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t)); 2164 meta_size += nreftablee * sizeof(uint64_t); 2165 2166 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2167 aligned_total_size + meta_size, &error_abort); 2168 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2169 &error_abort); 2170 } 2171 2172 ret = bdrv_create_file(filename, opts, &local_err); 2173 if (ret < 0) { 2174 error_propagate(errp, local_err); 2175 return ret; 2176 } 2177 2178 blk = blk_new_open(filename, NULL, NULL, 2179 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); 2180 if (blk == NULL) { 2181 error_propagate(errp, local_err); 2182 return -EIO; 2183 } 2184 2185 blk_set_allow_write_beyond_eof(blk, true); 2186 2187 /* Write the header */ 2188 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2189 header = g_malloc0(cluster_size); 2190 *header = (QCowHeader) { 2191 .magic = cpu_to_be32(QCOW_MAGIC), 2192 .version = cpu_to_be32(version), 2193 .cluster_bits = cpu_to_be32(cluster_bits), 2194 .size = cpu_to_be64(0), 2195 .l1_table_offset = cpu_to_be64(0), 2196 .l1_size = cpu_to_be32(0), 2197 .refcount_table_offset = cpu_to_be64(cluster_size), 2198 .refcount_table_clusters = cpu_to_be32(1), 2199 .refcount_order = cpu_to_be32(refcount_order), 2200 .header_length = cpu_to_be32(sizeof(*header)), 2201 }; 2202 2203 if (flags & BLOCK_FLAG_ENCRYPT) { 2204 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2205 } else { 2206 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2207 } 2208 2209 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2210 header->compatible_features |= 2211 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2212 } 2213 2214 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2215 g_free(header); 2216 if (ret < 0) { 2217 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2218 goto out; 2219 } 2220 2221 /* Write a refcount table with one refcount block */ 2222 refcount_table = g_malloc0(2 * cluster_size); 2223 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2224 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2225 g_free(refcount_table); 2226 2227 if (ret < 0) { 2228 error_setg_errno(errp, -ret, "Could not write refcount table"); 2229 goto out; 2230 } 2231 2232 blk_unref(blk); 2233 blk = NULL; 2234 2235 /* 2236 * And now open the image and make it consistent first (i.e. increase the 2237 * refcount of the cluster that is occupied by the header and the refcount 2238 * table) 2239 */ 2240 options = qdict_new(); 2241 qdict_put(options, "driver", qstring_from_str("qcow2")); 2242 blk = blk_new_open(filename, NULL, options, 2243 BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err); 2244 if (blk == NULL) { 2245 error_propagate(errp, local_err); 2246 ret = -EIO; 2247 goto out; 2248 } 2249 2250 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2251 if (ret < 0) { 2252 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2253 "header and refcount table"); 2254 goto out; 2255 2256 } else if (ret != 0) { 2257 error_report("Huh, first cluster in empty image is already in use?"); 2258 abort(); 2259 } 2260 2261 /* Create a full header (including things like feature table) */ 2262 ret = qcow2_update_header(blk_bs(blk)); 2263 if (ret < 0) { 2264 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2265 goto out; 2266 } 2267 2268 /* Okay, now that we have a valid image, let's give it the right size */ 2269 ret = blk_truncate(blk, total_size); 2270 if (ret < 0) { 2271 error_setg_errno(errp, -ret, "Could not resize image"); 2272 goto out; 2273 } 2274 2275 /* Want a backing file? There you go.*/ 2276 if (backing_file) { 2277 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2278 if (ret < 0) { 2279 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2280 "with format '%s'", backing_file, backing_format); 2281 goto out; 2282 } 2283 } 2284 2285 /* And if we're supposed to preallocate metadata, do that now */ 2286 if (prealloc != PREALLOC_MODE_OFF) { 2287 BDRVQcow2State *s = blk_bs(blk)->opaque; 2288 qemu_co_mutex_lock(&s->lock); 2289 ret = preallocate(blk_bs(blk)); 2290 qemu_co_mutex_unlock(&s->lock); 2291 if (ret < 0) { 2292 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2293 goto out; 2294 } 2295 } 2296 2297 blk_unref(blk); 2298 blk = NULL; 2299 2300 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2301 options = qdict_new(); 2302 qdict_put(options, "driver", qstring_from_str("qcow2")); 2303 blk = blk_new_open(filename, NULL, options, 2304 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err); 2305 if (blk == NULL) { 2306 error_propagate(errp, local_err); 2307 ret = -EIO; 2308 goto out; 2309 } 2310 2311 ret = 0; 2312 out: 2313 if (blk) { 2314 blk_unref(blk); 2315 } 2316 return ret; 2317 } 2318 2319 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2320 { 2321 char *backing_file = NULL; 2322 char *backing_fmt = NULL; 2323 char *buf = NULL; 2324 uint64_t size = 0; 2325 int flags = 0; 2326 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2327 PreallocMode prealloc; 2328 int version = 3; 2329 uint64_t refcount_bits = 16; 2330 int refcount_order; 2331 Error *local_err = NULL; 2332 int ret; 2333 2334 /* Read out options */ 2335 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2336 BDRV_SECTOR_SIZE); 2337 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2338 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2339 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2340 flags |= BLOCK_FLAG_ENCRYPT; 2341 } 2342 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2343 DEFAULT_CLUSTER_SIZE); 2344 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2345 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2346 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2347 &local_err); 2348 if (local_err) { 2349 error_propagate(errp, local_err); 2350 ret = -EINVAL; 2351 goto finish; 2352 } 2353 g_free(buf); 2354 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2355 if (!buf) { 2356 /* keep the default */ 2357 } else if (!strcmp(buf, "0.10")) { 2358 version = 2; 2359 } else if (!strcmp(buf, "1.1")) { 2360 version = 3; 2361 } else { 2362 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2363 ret = -EINVAL; 2364 goto finish; 2365 } 2366 2367 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2368 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2369 } 2370 2371 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2372 error_setg(errp, "Backing file and preallocation cannot be used at " 2373 "the same time"); 2374 ret = -EINVAL; 2375 goto finish; 2376 } 2377 2378 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2379 error_setg(errp, "Lazy refcounts only supported with compatibility " 2380 "level 1.1 and above (use compat=1.1 or greater)"); 2381 ret = -EINVAL; 2382 goto finish; 2383 } 2384 2385 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2386 refcount_bits); 2387 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2388 error_setg(errp, "Refcount width must be a power of two and may not " 2389 "exceed 64 bits"); 2390 ret = -EINVAL; 2391 goto finish; 2392 } 2393 2394 if (version < 3 && refcount_bits != 16) { 2395 error_setg(errp, "Different refcount widths than 16 bits require " 2396 "compatibility level 1.1 or above (use compat=1.1 or " 2397 "greater)"); 2398 ret = -EINVAL; 2399 goto finish; 2400 } 2401 2402 refcount_order = ctz32(refcount_bits); 2403 2404 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2405 cluster_size, prealloc, opts, version, refcount_order, 2406 &local_err); 2407 error_propagate(errp, local_err); 2408 2409 finish: 2410 g_free(backing_file); 2411 g_free(backing_fmt); 2412 g_free(buf); 2413 return ret; 2414 } 2415 2416 2417 static bool is_zero_sectors(BlockDriverState *bs, int64_t start, 2418 uint32_t count) 2419 { 2420 int nr; 2421 BlockDriverState *file; 2422 int64_t res; 2423 2424 if (!count) { 2425 return true; 2426 } 2427 res = bdrv_get_block_status_above(bs, NULL, start, count, 2428 &nr, &file); 2429 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count; 2430 } 2431 2432 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 2433 int64_t offset, int count, BdrvRequestFlags flags) 2434 { 2435 int ret; 2436 BDRVQcow2State *s = bs->opaque; 2437 2438 uint32_t head = offset % s->cluster_size; 2439 uint32_t tail = (offset + count) % s->cluster_size; 2440 2441 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, count); 2442 2443 if (head || tail) { 2444 int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS; 2445 uint64_t off; 2446 unsigned int nr; 2447 2448 assert(head + count <= s->cluster_size); 2449 2450 /* check whether remainder of cluster already reads as zero */ 2451 if (!(is_zero_sectors(bs, cl_start, 2452 DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) && 2453 is_zero_sectors(bs, (offset + count) >> BDRV_SECTOR_BITS, 2454 DIV_ROUND_UP(-tail & (s->cluster_size - 1), 2455 BDRV_SECTOR_SIZE)))) { 2456 return -ENOTSUP; 2457 } 2458 2459 qemu_co_mutex_lock(&s->lock); 2460 /* We can have new write after previous check */ 2461 offset = cl_start << BDRV_SECTOR_BITS; 2462 count = s->cluster_size; 2463 nr = s->cluster_size; 2464 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 2465 if (ret != QCOW2_CLUSTER_UNALLOCATED && ret != QCOW2_CLUSTER_ZERO) { 2466 qemu_co_mutex_unlock(&s->lock); 2467 return -ENOTSUP; 2468 } 2469 } else { 2470 qemu_co_mutex_lock(&s->lock); 2471 } 2472 2473 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, count); 2474 2475 /* Whatever is left can use real zero clusters */ 2476 ret = qcow2_zero_clusters(bs, offset, count >> BDRV_SECTOR_BITS); 2477 qemu_co_mutex_unlock(&s->lock); 2478 2479 return ret; 2480 } 2481 2482 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 2483 int64_t offset, int count) 2484 { 2485 int ret; 2486 BDRVQcow2State *s = bs->opaque; 2487 2488 qemu_co_mutex_lock(&s->lock); 2489 ret = qcow2_discard_clusters(bs, offset, count >> BDRV_SECTOR_BITS, 2490 QCOW2_DISCARD_REQUEST, false); 2491 qemu_co_mutex_unlock(&s->lock); 2492 return ret; 2493 } 2494 2495 static int qcow2_truncate(BlockDriverState *bs, int64_t offset) 2496 { 2497 BDRVQcow2State *s = bs->opaque; 2498 int64_t new_l1_size; 2499 int ret; 2500 2501 if (offset & 511) { 2502 error_report("The new size must be a multiple of 512"); 2503 return -EINVAL; 2504 } 2505 2506 /* cannot proceed if image has snapshots */ 2507 if (s->nb_snapshots) { 2508 error_report("Can't resize an image which has snapshots"); 2509 return -ENOTSUP; 2510 } 2511 2512 /* shrinking is currently not supported */ 2513 if (offset < bs->total_sectors * 512) { 2514 error_report("qcow2 doesn't support shrinking images yet"); 2515 return -ENOTSUP; 2516 } 2517 2518 new_l1_size = size_to_l1(s, offset); 2519 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2520 if (ret < 0) { 2521 return ret; 2522 } 2523 2524 /* write updated header.size */ 2525 offset = cpu_to_be64(offset); 2526 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 2527 &offset, sizeof(uint64_t)); 2528 if (ret < 0) { 2529 return ret; 2530 } 2531 2532 s->l1_vm_state_index = new_l1_size; 2533 return 0; 2534 } 2535 2536 typedef struct Qcow2WriteCo { 2537 BlockDriverState *bs; 2538 int64_t sector_num; 2539 const uint8_t *buf; 2540 int nb_sectors; 2541 int ret; 2542 } Qcow2WriteCo; 2543 2544 static void qcow2_write_co_entry(void *opaque) 2545 { 2546 Qcow2WriteCo *co = opaque; 2547 QEMUIOVector qiov; 2548 uint64_t offset = co->sector_num * BDRV_SECTOR_SIZE; 2549 uint64_t bytes = co->nb_sectors * BDRV_SECTOR_SIZE; 2550 2551 struct iovec iov = (struct iovec) { 2552 .iov_base = (uint8_t*) co->buf, 2553 .iov_len = bytes, 2554 }; 2555 qemu_iovec_init_external(&qiov, &iov, 1); 2556 2557 co->ret = qcow2_co_pwritev(co->bs, offset, bytes, &qiov, 0); 2558 } 2559 2560 /* Wrapper for non-coroutine contexts */ 2561 static int qcow2_write(BlockDriverState *bs, int64_t sector_num, 2562 const uint8_t *buf, int nb_sectors) 2563 { 2564 Coroutine *co; 2565 AioContext *aio_context = bdrv_get_aio_context(bs); 2566 Qcow2WriteCo data = { 2567 .bs = bs, 2568 .sector_num = sector_num, 2569 .buf = buf, 2570 .nb_sectors = nb_sectors, 2571 .ret = -EINPROGRESS, 2572 }; 2573 co = qemu_coroutine_create(qcow2_write_co_entry, &data); 2574 qemu_coroutine_enter(co); 2575 while (data.ret == -EINPROGRESS) { 2576 aio_poll(aio_context, true); 2577 } 2578 return data.ret; 2579 } 2580 2581 /* XXX: put compressed sectors first, then all the cluster aligned 2582 tables to avoid losing bytes in alignment */ 2583 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, 2584 const uint8_t *buf, int nb_sectors) 2585 { 2586 BDRVQcow2State *s = bs->opaque; 2587 z_stream strm; 2588 int ret, out_len; 2589 uint8_t *out_buf; 2590 uint64_t cluster_offset; 2591 2592 if (nb_sectors == 0) { 2593 /* align end of file to a sector boundary to ease reading with 2594 sector based I/Os */ 2595 cluster_offset = bdrv_getlength(bs->file->bs); 2596 return bdrv_truncate(bs->file->bs, cluster_offset); 2597 } 2598 2599 if (nb_sectors != s->cluster_sectors) { 2600 ret = -EINVAL; 2601 2602 /* Zero-pad last write if image size is not cluster aligned */ 2603 if (sector_num + nb_sectors == bs->total_sectors && 2604 nb_sectors < s->cluster_sectors) { 2605 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 2606 memset(pad_buf, 0, s->cluster_size); 2607 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 2608 ret = qcow2_write_compressed(bs, sector_num, 2609 pad_buf, s->cluster_sectors); 2610 qemu_vfree(pad_buf); 2611 } 2612 return ret; 2613 } 2614 2615 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 2616 2617 /* best compression, small window, no zlib header */ 2618 memset(&strm, 0, sizeof(strm)); 2619 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2620 Z_DEFLATED, -12, 2621 9, Z_DEFAULT_STRATEGY); 2622 if (ret != 0) { 2623 ret = -EINVAL; 2624 goto fail; 2625 } 2626 2627 strm.avail_in = s->cluster_size; 2628 strm.next_in = (uint8_t *)buf; 2629 strm.avail_out = s->cluster_size; 2630 strm.next_out = out_buf; 2631 2632 ret = deflate(&strm, Z_FINISH); 2633 if (ret != Z_STREAM_END && ret != Z_OK) { 2634 deflateEnd(&strm); 2635 ret = -EINVAL; 2636 goto fail; 2637 } 2638 out_len = strm.next_out - out_buf; 2639 2640 deflateEnd(&strm); 2641 2642 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2643 /* could not compress: write normal cluster */ 2644 ret = qcow2_write(bs, sector_num, buf, s->cluster_sectors); 2645 if (ret < 0) { 2646 goto fail; 2647 } 2648 } else { 2649 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs, 2650 sector_num << 9, out_len); 2651 if (!cluster_offset) { 2652 ret = -EIO; 2653 goto fail; 2654 } 2655 cluster_offset &= s->cluster_offset_mask; 2656 2657 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2658 if (ret < 0) { 2659 goto fail; 2660 } 2661 2662 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2663 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); 2664 if (ret < 0) { 2665 goto fail; 2666 } 2667 } 2668 2669 ret = 0; 2670 fail: 2671 g_free(out_buf); 2672 return ret; 2673 } 2674 2675 static int make_completely_empty(BlockDriverState *bs) 2676 { 2677 BDRVQcow2State *s = bs->opaque; 2678 int ret, l1_clusters; 2679 int64_t offset; 2680 uint64_t *new_reftable = NULL; 2681 uint64_t rt_entry, l1_size2; 2682 struct { 2683 uint64_t l1_offset; 2684 uint64_t reftable_offset; 2685 uint32_t reftable_clusters; 2686 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2687 2688 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2689 if (ret < 0) { 2690 goto fail; 2691 } 2692 2693 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2694 if (ret < 0) { 2695 goto fail; 2696 } 2697 2698 /* Refcounts will be broken utterly */ 2699 ret = qcow2_mark_dirty(bs); 2700 if (ret < 0) { 2701 goto fail; 2702 } 2703 2704 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2705 2706 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2707 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2708 2709 /* After this call, neither the in-memory nor the on-disk refcount 2710 * information accurately describe the actual references */ 2711 2712 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 2713 l1_clusters * s->cluster_size, 0); 2714 if (ret < 0) { 2715 goto fail_broken_refcounts; 2716 } 2717 memset(s->l1_table, 0, l1_size2); 2718 2719 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2720 2721 /* Overwrite enough clusters at the beginning of the sectors to place 2722 * the refcount table, a refcount block and the L1 table in; this may 2723 * overwrite parts of the existing refcount and L1 table, which is not 2724 * an issue because the dirty flag is set, complete data loss is in fact 2725 * desired and partial data loss is consequently fine as well */ 2726 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 2727 (2 + l1_clusters) * s->cluster_size, 0); 2728 /* This call (even if it failed overall) may have overwritten on-disk 2729 * refcount structures; in that case, the in-memory refcount information 2730 * will probably differ from the on-disk information which makes the BDS 2731 * unusable */ 2732 if (ret < 0) { 2733 goto fail_broken_refcounts; 2734 } 2735 2736 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2737 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2738 2739 /* "Create" an empty reftable (one cluster) directly after the image 2740 * header and an empty L1 table three clusters after the image header; 2741 * the cluster between those two will be used as the first refblock */ 2742 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 2743 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 2744 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 2745 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 2746 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2747 if (ret < 0) { 2748 goto fail_broken_refcounts; 2749 } 2750 2751 s->l1_table_offset = 3 * s->cluster_size; 2752 2753 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2754 if (!new_reftable) { 2755 ret = -ENOMEM; 2756 goto fail_broken_refcounts; 2757 } 2758 2759 s->refcount_table_offset = s->cluster_size; 2760 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2761 2762 g_free(s->refcount_table); 2763 s->refcount_table = new_reftable; 2764 new_reftable = NULL; 2765 2766 /* Now the in-memory refcount information again corresponds to the on-disk 2767 * information (reftable is empty and no refblocks (the refblock cache is 2768 * empty)); however, this means some clusters (e.g. the image header) are 2769 * referenced, but not refcounted, but the normal qcow2 code assumes that 2770 * the in-memory information is always correct */ 2771 2772 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2773 2774 /* Enter the first refblock into the reftable */ 2775 rt_entry = cpu_to_be64(2 * s->cluster_size); 2776 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 2777 &rt_entry, sizeof(rt_entry)); 2778 if (ret < 0) { 2779 goto fail_broken_refcounts; 2780 } 2781 s->refcount_table[0] = 2 * s->cluster_size; 2782 2783 s->free_cluster_index = 0; 2784 assert(3 + l1_clusters <= s->refcount_block_size); 2785 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2786 if (offset < 0) { 2787 ret = offset; 2788 goto fail_broken_refcounts; 2789 } else if (offset > 0) { 2790 error_report("First cluster in emptied image is in use"); 2791 abort(); 2792 } 2793 2794 /* Now finally the in-memory information corresponds to the on-disk 2795 * structures and is correct */ 2796 ret = qcow2_mark_clean(bs); 2797 if (ret < 0) { 2798 goto fail; 2799 } 2800 2801 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size); 2802 if (ret < 0) { 2803 goto fail; 2804 } 2805 2806 return 0; 2807 2808 fail_broken_refcounts: 2809 /* The BDS is unusable at this point. If we wanted to make it usable, we 2810 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2811 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2812 * again. However, because the functions which could have caused this error 2813 * path to be taken are used by those functions as well, it's very likely 2814 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2815 bs->drv = NULL; 2816 2817 fail: 2818 g_free(new_reftable); 2819 return ret; 2820 } 2821 2822 static int qcow2_make_empty(BlockDriverState *bs) 2823 { 2824 BDRVQcow2State *s = bs->opaque; 2825 uint64_t start_sector; 2826 int sector_step = INT_MAX / BDRV_SECTOR_SIZE; 2827 int l1_clusters, ret = 0; 2828 2829 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2830 2831 if (s->qcow_version >= 3 && !s->snapshots && 2832 3 + l1_clusters <= s->refcount_block_size) { 2833 /* The following function only works for qcow2 v3 images (it requires 2834 * the dirty flag) and only as long as there are no snapshots (because 2835 * it completely empties the image). Furthermore, the L1 table and three 2836 * additional clusters (image header, refcount table, one refcount 2837 * block) have to fit inside one refcount block. */ 2838 return make_completely_empty(bs); 2839 } 2840 2841 /* This fallback code simply discards every active cluster; this is slow, 2842 * but works in all cases */ 2843 for (start_sector = 0; start_sector < bs->total_sectors; 2844 start_sector += sector_step) 2845 { 2846 /* As this function is generally used after committing an external 2847 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2848 * default action for this kind of discard is to pass the discard, 2849 * which will ideally result in an actually smaller image file, as 2850 * is probably desired. */ 2851 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE, 2852 MIN(sector_step, 2853 bs->total_sectors - start_sector), 2854 QCOW2_DISCARD_SNAPSHOT, true); 2855 if (ret < 0) { 2856 break; 2857 } 2858 } 2859 2860 return ret; 2861 } 2862 2863 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2864 { 2865 BDRVQcow2State *s = bs->opaque; 2866 int ret; 2867 2868 qemu_co_mutex_lock(&s->lock); 2869 ret = qcow2_cache_write(bs, s->l2_table_cache); 2870 if (ret < 0) { 2871 qemu_co_mutex_unlock(&s->lock); 2872 return ret; 2873 } 2874 2875 if (qcow2_need_accurate_refcounts(s)) { 2876 ret = qcow2_cache_write(bs, s->refcount_block_cache); 2877 if (ret < 0) { 2878 qemu_co_mutex_unlock(&s->lock); 2879 return ret; 2880 } 2881 } 2882 qemu_co_mutex_unlock(&s->lock); 2883 2884 return 0; 2885 } 2886 2887 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2888 { 2889 BDRVQcow2State *s = bs->opaque; 2890 bdi->unallocated_blocks_are_zero = true; 2891 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2892 bdi->cluster_size = s->cluster_size; 2893 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2894 return 0; 2895 } 2896 2897 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2898 { 2899 BDRVQcow2State *s = bs->opaque; 2900 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2901 2902 *spec_info = (ImageInfoSpecific){ 2903 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2904 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 2905 }; 2906 if (s->qcow_version == 2) { 2907 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2908 .compat = g_strdup("0.10"), 2909 .refcount_bits = s->refcount_bits, 2910 }; 2911 } else if (s->qcow_version == 3) { 2912 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2913 .compat = g_strdup("1.1"), 2914 .lazy_refcounts = s->compatible_features & 2915 QCOW2_COMPAT_LAZY_REFCOUNTS, 2916 .has_lazy_refcounts = true, 2917 .corrupt = s->incompatible_features & 2918 QCOW2_INCOMPAT_CORRUPT, 2919 .has_corrupt = true, 2920 .refcount_bits = s->refcount_bits, 2921 }; 2922 } else { 2923 /* if this assertion fails, this probably means a new version was 2924 * added without having it covered here */ 2925 assert(false); 2926 } 2927 2928 return spec_info; 2929 } 2930 2931 #if 0 2932 static void dump_refcounts(BlockDriverState *bs) 2933 { 2934 BDRVQcow2State *s = bs->opaque; 2935 int64_t nb_clusters, k, k1, size; 2936 int refcount; 2937 2938 size = bdrv_getlength(bs->file->bs); 2939 nb_clusters = size_to_clusters(s, size); 2940 for(k = 0; k < nb_clusters;) { 2941 k1 = k; 2942 refcount = get_refcount(bs, k); 2943 k++; 2944 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2945 k++; 2946 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2947 k - k1); 2948 } 2949 } 2950 #endif 2951 2952 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2953 int64_t pos) 2954 { 2955 BDRVQcow2State *s = bs->opaque; 2956 2957 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2958 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 2959 qiov->size, qiov, 0); 2960 } 2961 2962 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2963 int64_t pos) 2964 { 2965 BDRVQcow2State *s = bs->opaque; 2966 2967 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2968 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 2969 qiov->size, qiov, 0); 2970 } 2971 2972 /* 2973 * Downgrades an image's version. To achieve this, any incompatible features 2974 * have to be removed. 2975 */ 2976 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2977 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2978 { 2979 BDRVQcow2State *s = bs->opaque; 2980 int current_version = s->qcow_version; 2981 int ret; 2982 2983 if (target_version == current_version) { 2984 return 0; 2985 } else if (target_version > current_version) { 2986 return -EINVAL; 2987 } else if (target_version != 2) { 2988 return -EINVAL; 2989 } 2990 2991 if (s->refcount_order != 4) { 2992 error_report("compat=0.10 requires refcount_bits=16"); 2993 return -ENOTSUP; 2994 } 2995 2996 /* clear incompatible features */ 2997 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 2998 ret = qcow2_mark_clean(bs); 2999 if (ret < 0) { 3000 return ret; 3001 } 3002 } 3003 3004 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 3005 * the first place; if that happens nonetheless, returning -ENOTSUP is the 3006 * best thing to do anyway */ 3007 3008 if (s->incompatible_features) { 3009 return -ENOTSUP; 3010 } 3011 3012 /* since we can ignore compatible features, we can set them to 0 as well */ 3013 s->compatible_features = 0; 3014 /* if lazy refcounts have been used, they have already been fixed through 3015 * clearing the dirty flag */ 3016 3017 /* clearing autoclear features is trivial */ 3018 s->autoclear_features = 0; 3019 3020 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 3021 if (ret < 0) { 3022 return ret; 3023 } 3024 3025 s->qcow_version = target_version; 3026 ret = qcow2_update_header(bs); 3027 if (ret < 0) { 3028 s->qcow_version = current_version; 3029 return ret; 3030 } 3031 return 0; 3032 } 3033 3034 typedef enum Qcow2AmendOperation { 3035 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 3036 * statically initialized to so that the helper CB can discern the first 3037 * invocation from an operation change */ 3038 QCOW2_NO_OPERATION = 0, 3039 3040 QCOW2_CHANGING_REFCOUNT_ORDER, 3041 QCOW2_DOWNGRADING, 3042 } Qcow2AmendOperation; 3043 3044 typedef struct Qcow2AmendHelperCBInfo { 3045 /* The code coordinating the amend operations should only modify 3046 * these four fields; the rest will be managed by the CB */ 3047 BlockDriverAmendStatusCB *original_status_cb; 3048 void *original_cb_opaque; 3049 3050 Qcow2AmendOperation current_operation; 3051 3052 /* Total number of operations to perform (only set once) */ 3053 int total_operations; 3054 3055 /* The following fields are managed by the CB */ 3056 3057 /* Number of operations completed */ 3058 int operations_completed; 3059 3060 /* Cumulative offset of all completed operations */ 3061 int64_t offset_completed; 3062 3063 Qcow2AmendOperation last_operation; 3064 int64_t last_work_size; 3065 } Qcow2AmendHelperCBInfo; 3066 3067 static void qcow2_amend_helper_cb(BlockDriverState *bs, 3068 int64_t operation_offset, 3069 int64_t operation_work_size, void *opaque) 3070 { 3071 Qcow2AmendHelperCBInfo *info = opaque; 3072 int64_t current_work_size; 3073 int64_t projected_work_size; 3074 3075 if (info->current_operation != info->last_operation) { 3076 if (info->last_operation != QCOW2_NO_OPERATION) { 3077 info->offset_completed += info->last_work_size; 3078 info->operations_completed++; 3079 } 3080 3081 info->last_operation = info->current_operation; 3082 } 3083 3084 assert(info->total_operations > 0); 3085 assert(info->operations_completed < info->total_operations); 3086 3087 info->last_work_size = operation_work_size; 3088 3089 current_work_size = info->offset_completed + operation_work_size; 3090 3091 /* current_work_size is the total work size for (operations_completed + 1) 3092 * operations (which includes this one), so multiply it by the number of 3093 * operations not covered and divide it by the number of operations 3094 * covered to get a projection for the operations not covered */ 3095 projected_work_size = current_work_size * (info->total_operations - 3096 info->operations_completed - 1) 3097 / (info->operations_completed + 1); 3098 3099 info->original_status_cb(bs, info->offset_completed + operation_offset, 3100 current_work_size + projected_work_size, 3101 info->original_cb_opaque); 3102 } 3103 3104 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3105 BlockDriverAmendStatusCB *status_cb, 3106 void *cb_opaque) 3107 { 3108 BDRVQcow2State *s = bs->opaque; 3109 int old_version = s->qcow_version, new_version = old_version; 3110 uint64_t new_size = 0; 3111 const char *backing_file = NULL, *backing_format = NULL; 3112 bool lazy_refcounts = s->use_lazy_refcounts; 3113 const char *compat = NULL; 3114 uint64_t cluster_size = s->cluster_size; 3115 bool encrypt; 3116 int refcount_bits = s->refcount_bits; 3117 int ret; 3118 QemuOptDesc *desc = opts->list->desc; 3119 Qcow2AmendHelperCBInfo helper_cb_info; 3120 3121 while (desc && desc->name) { 3122 if (!qemu_opt_find(opts, desc->name)) { 3123 /* only change explicitly defined options */ 3124 desc++; 3125 continue; 3126 } 3127 3128 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3129 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3130 if (!compat) { 3131 /* preserve default */ 3132 } else if (!strcmp(compat, "0.10")) { 3133 new_version = 2; 3134 } else if (!strcmp(compat, "1.1")) { 3135 new_version = 3; 3136 } else { 3137 error_report("Unknown compatibility level %s", compat); 3138 return -EINVAL; 3139 } 3140 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3141 error_report("Cannot change preallocation mode"); 3142 return -ENOTSUP; 3143 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3144 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3145 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3146 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3147 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3148 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3149 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3150 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3151 !!s->cipher); 3152 3153 if (encrypt != !!s->cipher) { 3154 error_report("Changing the encryption flag is not supported"); 3155 return -ENOTSUP; 3156 } 3157 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3158 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3159 cluster_size); 3160 if (cluster_size != s->cluster_size) { 3161 error_report("Changing the cluster size is not supported"); 3162 return -ENOTSUP; 3163 } 3164 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3165 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3166 lazy_refcounts); 3167 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3168 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3169 refcount_bits); 3170 3171 if (refcount_bits <= 0 || refcount_bits > 64 || 3172 !is_power_of_2(refcount_bits)) 3173 { 3174 error_report("Refcount width must be a power of two and may " 3175 "not exceed 64 bits"); 3176 return -EINVAL; 3177 } 3178 } else { 3179 /* if this point is reached, this probably means a new option was 3180 * added without having it covered here */ 3181 abort(); 3182 } 3183 3184 desc++; 3185 } 3186 3187 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3188 .original_status_cb = status_cb, 3189 .original_cb_opaque = cb_opaque, 3190 .total_operations = (new_version < old_version) 3191 + (s->refcount_bits != refcount_bits) 3192 }; 3193 3194 /* Upgrade first (some features may require compat=1.1) */ 3195 if (new_version > old_version) { 3196 s->qcow_version = new_version; 3197 ret = qcow2_update_header(bs); 3198 if (ret < 0) { 3199 s->qcow_version = old_version; 3200 return ret; 3201 } 3202 } 3203 3204 if (s->refcount_bits != refcount_bits) { 3205 int refcount_order = ctz32(refcount_bits); 3206 Error *local_error = NULL; 3207 3208 if (new_version < 3 && refcount_bits != 16) { 3209 error_report("Different refcount widths than 16 bits require " 3210 "compatibility level 1.1 or above (use compat=1.1 or " 3211 "greater)"); 3212 return -EINVAL; 3213 } 3214 3215 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3216 ret = qcow2_change_refcount_order(bs, refcount_order, 3217 &qcow2_amend_helper_cb, 3218 &helper_cb_info, &local_error); 3219 if (ret < 0) { 3220 error_report_err(local_error); 3221 return ret; 3222 } 3223 } 3224 3225 if (backing_file || backing_format) { 3226 ret = qcow2_change_backing_file(bs, 3227 backing_file ?: s->image_backing_file, 3228 backing_format ?: s->image_backing_format); 3229 if (ret < 0) { 3230 return ret; 3231 } 3232 } 3233 3234 if (s->use_lazy_refcounts != lazy_refcounts) { 3235 if (lazy_refcounts) { 3236 if (new_version < 3) { 3237 error_report("Lazy refcounts only supported with compatibility " 3238 "level 1.1 and above (use compat=1.1 or greater)"); 3239 return -EINVAL; 3240 } 3241 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3242 ret = qcow2_update_header(bs); 3243 if (ret < 0) { 3244 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3245 return ret; 3246 } 3247 s->use_lazy_refcounts = true; 3248 } else { 3249 /* make image clean first */ 3250 ret = qcow2_mark_clean(bs); 3251 if (ret < 0) { 3252 return ret; 3253 } 3254 /* now disallow lazy refcounts */ 3255 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3256 ret = qcow2_update_header(bs); 3257 if (ret < 0) { 3258 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3259 return ret; 3260 } 3261 s->use_lazy_refcounts = false; 3262 } 3263 } 3264 3265 if (new_size) { 3266 ret = bdrv_truncate(bs, new_size); 3267 if (ret < 0) { 3268 return ret; 3269 } 3270 } 3271 3272 /* Downgrade last (so unsupported features can be removed before) */ 3273 if (new_version < old_version) { 3274 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3275 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3276 &helper_cb_info); 3277 if (ret < 0) { 3278 return ret; 3279 } 3280 } 3281 3282 return 0; 3283 } 3284 3285 /* 3286 * If offset or size are negative, respectively, they will not be included in 3287 * the BLOCK_IMAGE_CORRUPTED event emitted. 3288 * fatal will be ignored for read-only BDS; corruptions found there will always 3289 * be considered non-fatal. 3290 */ 3291 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3292 int64_t size, const char *message_format, ...) 3293 { 3294 BDRVQcow2State *s = bs->opaque; 3295 const char *node_name; 3296 char *message; 3297 va_list ap; 3298 3299 fatal = fatal && !bs->read_only; 3300 3301 if (s->signaled_corruption && 3302 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3303 { 3304 return; 3305 } 3306 3307 va_start(ap, message_format); 3308 message = g_strdup_vprintf(message_format, ap); 3309 va_end(ap); 3310 3311 if (fatal) { 3312 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3313 "corruption events will be suppressed\n", message); 3314 } else { 3315 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3316 "corruption events will be suppressed\n", message); 3317 } 3318 3319 node_name = bdrv_get_node_name(bs); 3320 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3321 *node_name != '\0', node_name, 3322 message, offset >= 0, offset, 3323 size >= 0, size, 3324 fatal, &error_abort); 3325 g_free(message); 3326 3327 if (fatal) { 3328 qcow2_mark_corrupt(bs); 3329 bs->drv = NULL; /* make BDS unusable */ 3330 } 3331 3332 s->signaled_corruption = true; 3333 } 3334 3335 static QemuOptsList qcow2_create_opts = { 3336 .name = "qcow2-create-opts", 3337 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3338 .desc = { 3339 { 3340 .name = BLOCK_OPT_SIZE, 3341 .type = QEMU_OPT_SIZE, 3342 .help = "Virtual disk size" 3343 }, 3344 { 3345 .name = BLOCK_OPT_COMPAT_LEVEL, 3346 .type = QEMU_OPT_STRING, 3347 .help = "Compatibility level (0.10 or 1.1)" 3348 }, 3349 { 3350 .name = BLOCK_OPT_BACKING_FILE, 3351 .type = QEMU_OPT_STRING, 3352 .help = "File name of a base image" 3353 }, 3354 { 3355 .name = BLOCK_OPT_BACKING_FMT, 3356 .type = QEMU_OPT_STRING, 3357 .help = "Image format of the base image" 3358 }, 3359 { 3360 .name = BLOCK_OPT_ENCRYPT, 3361 .type = QEMU_OPT_BOOL, 3362 .help = "Encrypt the image", 3363 .def_value_str = "off" 3364 }, 3365 { 3366 .name = BLOCK_OPT_CLUSTER_SIZE, 3367 .type = QEMU_OPT_SIZE, 3368 .help = "qcow2 cluster size", 3369 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3370 }, 3371 { 3372 .name = BLOCK_OPT_PREALLOC, 3373 .type = QEMU_OPT_STRING, 3374 .help = "Preallocation mode (allowed values: off, metadata, " 3375 "falloc, full)" 3376 }, 3377 { 3378 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3379 .type = QEMU_OPT_BOOL, 3380 .help = "Postpone refcount updates", 3381 .def_value_str = "off" 3382 }, 3383 { 3384 .name = BLOCK_OPT_REFCOUNT_BITS, 3385 .type = QEMU_OPT_NUMBER, 3386 .help = "Width of a reference count entry in bits", 3387 .def_value_str = "16" 3388 }, 3389 { /* end of list */ } 3390 } 3391 }; 3392 3393 BlockDriver bdrv_qcow2 = { 3394 .format_name = "qcow2", 3395 .instance_size = sizeof(BDRVQcow2State), 3396 .bdrv_probe = qcow2_probe, 3397 .bdrv_open = qcow2_open, 3398 .bdrv_close = qcow2_close, 3399 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3400 .bdrv_reopen_commit = qcow2_reopen_commit, 3401 .bdrv_reopen_abort = qcow2_reopen_abort, 3402 .bdrv_join_options = qcow2_join_options, 3403 .bdrv_create = qcow2_create, 3404 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3405 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3406 .bdrv_set_key = qcow2_set_key, 3407 3408 .bdrv_co_preadv = qcow2_co_preadv, 3409 .bdrv_co_pwritev = qcow2_co_pwritev, 3410 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3411 3412 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 3413 .bdrv_co_pdiscard = qcow2_co_pdiscard, 3414 .bdrv_truncate = qcow2_truncate, 3415 .bdrv_write_compressed = qcow2_write_compressed, 3416 .bdrv_make_empty = qcow2_make_empty, 3417 3418 .bdrv_snapshot_create = qcow2_snapshot_create, 3419 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3420 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3421 .bdrv_snapshot_list = qcow2_snapshot_list, 3422 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3423 .bdrv_get_info = qcow2_get_info, 3424 .bdrv_get_specific_info = qcow2_get_specific_info, 3425 3426 .bdrv_save_vmstate = qcow2_save_vmstate, 3427 .bdrv_load_vmstate = qcow2_load_vmstate, 3428 3429 .supports_backing = true, 3430 .bdrv_change_backing_file = qcow2_change_backing_file, 3431 3432 .bdrv_refresh_limits = qcow2_refresh_limits, 3433 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3434 .bdrv_inactivate = qcow2_inactivate, 3435 3436 .create_opts = &qcow2_create_opts, 3437 .bdrv_check = qcow2_check, 3438 .bdrv_amend_options = qcow2_amend_options, 3439 3440 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3441 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3442 }; 3443 3444 static void bdrv_qcow2_init(void) 3445 { 3446 bdrv_register(&bdrv_qcow2); 3447 } 3448 3449 block_init(bdrv_qcow2_init); 3450