1 /* 2 * Block driver for the QCOW version 2 format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 #include "qemu/osdep.h" 25 #include "block/block_int.h" 26 #include "sysemu/block-backend.h" 27 #include "qemu/module.h" 28 #include <zlib.h> 29 #include "block/qcow2.h" 30 #include "qemu/error-report.h" 31 #include "qapi/qmp/qerror.h" 32 #include "qapi/qmp/qbool.h" 33 #include "qapi/util.h" 34 #include "qapi/qmp/types.h" 35 #include "qapi-event.h" 36 #include "trace.h" 37 #include "qemu/option_int.h" 38 #include "qemu/cutils.h" 39 #include "qemu/bswap.h" 40 41 /* 42 Differences with QCOW: 43 44 - Support for multiple incremental snapshots. 45 - Memory management by reference counts. 46 - Clusters which have a reference count of one have the bit 47 QCOW_OFLAG_COPIED to optimize write performance. 48 - Size of compressed clusters is stored in sectors to reduce bit usage 49 in the cluster offsets. 50 - Support for storing additional data (such as the VM state) in the 51 snapshots. 52 - If a backing store is used, the cluster size is not constrained 53 (could be backported to QCOW). 54 - L2 tables have always a size of one cluster. 55 */ 56 57 58 typedef struct { 59 uint32_t magic; 60 uint32_t len; 61 } QEMU_PACKED QCowExtension; 62 63 #define QCOW2_EXT_MAGIC_END 0 64 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA 65 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857 66 67 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename) 68 { 69 const QCowHeader *cow_header = (const void *)buf; 70 71 if (buf_size >= sizeof(QCowHeader) && 72 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 73 be32_to_cpu(cow_header->version) >= 2) 74 return 100; 75 else 76 return 0; 77 } 78 79 80 /* 81 * read qcow2 extension and fill bs 82 * start reading from start_offset 83 * finish reading upon magic of value 0 or when end_offset reached 84 * unknown magic is skipped (future extension this version knows nothing about) 85 * return 0 upon success, non-0 otherwise 86 */ 87 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, 88 uint64_t end_offset, void **p_feature_table, 89 Error **errp) 90 { 91 BDRVQcow2State *s = bs->opaque; 92 QCowExtension ext; 93 uint64_t offset; 94 int ret; 95 96 #ifdef DEBUG_EXT 97 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset); 98 #endif 99 offset = start_offset; 100 while (offset < end_offset) { 101 102 #ifdef DEBUG_EXT 103 /* Sanity check */ 104 if (offset > s->cluster_size) 105 printf("qcow2_read_extension: suspicious offset %lu\n", offset); 106 107 printf("attempting to read extended header in offset %lu\n", offset); 108 #endif 109 110 ret = bdrv_pread(bs->file, offset, &ext, sizeof(ext)); 111 if (ret < 0) { 112 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: " 113 "pread fail from offset %" PRIu64, offset); 114 return 1; 115 } 116 be32_to_cpus(&ext.magic); 117 be32_to_cpus(&ext.len); 118 offset += sizeof(ext); 119 #ifdef DEBUG_EXT 120 printf("ext.magic = 0x%x\n", ext.magic); 121 #endif 122 if (offset > end_offset || ext.len > end_offset - offset) { 123 error_setg(errp, "Header extension too large"); 124 return -EINVAL; 125 } 126 127 switch (ext.magic) { 128 case QCOW2_EXT_MAGIC_END: 129 return 0; 130 131 case QCOW2_EXT_MAGIC_BACKING_FORMAT: 132 if (ext.len >= sizeof(bs->backing_format)) { 133 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32 134 " too large (>=%zu)", ext.len, 135 sizeof(bs->backing_format)); 136 return 2; 137 } 138 ret = bdrv_pread(bs->file, offset, bs->backing_format, ext.len); 139 if (ret < 0) { 140 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: " 141 "Could not read format name"); 142 return 3; 143 } 144 bs->backing_format[ext.len] = '\0'; 145 s->image_backing_format = g_strdup(bs->backing_format); 146 #ifdef DEBUG_EXT 147 printf("Qcow2: Got format extension %s\n", bs->backing_format); 148 #endif 149 break; 150 151 case QCOW2_EXT_MAGIC_FEATURE_TABLE: 152 if (p_feature_table != NULL) { 153 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature)); 154 ret = bdrv_pread(bs->file, offset , feature_table, ext.len); 155 if (ret < 0) { 156 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: " 157 "Could not read table"); 158 return ret; 159 } 160 161 *p_feature_table = feature_table; 162 } 163 break; 164 165 default: 166 /* unknown magic - save it in case we need to rewrite the header */ 167 { 168 Qcow2UnknownHeaderExtension *uext; 169 170 uext = g_malloc0(sizeof(*uext) + ext.len); 171 uext->magic = ext.magic; 172 uext->len = ext.len; 173 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next); 174 175 ret = bdrv_pread(bs->file, offset , uext->data, uext->len); 176 if (ret < 0) { 177 error_setg_errno(errp, -ret, "ERROR: unknown extension: " 178 "Could not read data"); 179 return ret; 180 } 181 } 182 break; 183 } 184 185 offset += ((ext.len + 7) & ~7); 186 } 187 188 return 0; 189 } 190 191 static void cleanup_unknown_header_ext(BlockDriverState *bs) 192 { 193 BDRVQcow2State *s = bs->opaque; 194 Qcow2UnknownHeaderExtension *uext, *next; 195 196 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) { 197 QLIST_REMOVE(uext, next); 198 g_free(uext); 199 } 200 } 201 202 static void report_unsupported_feature(Error **errp, Qcow2Feature *table, 203 uint64_t mask) 204 { 205 char *features = g_strdup(""); 206 char *old; 207 208 while (table && table->name[0] != '\0') { 209 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) { 210 if (mask & (1ULL << table->bit)) { 211 old = features; 212 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "", 213 table->name); 214 g_free(old); 215 mask &= ~(1ULL << table->bit); 216 } 217 } 218 table++; 219 } 220 221 if (mask) { 222 old = features; 223 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64, 224 old, *old ? ", " : "", mask); 225 g_free(old); 226 } 227 228 error_setg(errp, "Unsupported qcow2 feature(s): %s", features); 229 g_free(features); 230 } 231 232 /* 233 * Sets the dirty bit and flushes afterwards if necessary. 234 * 235 * The incompatible_features bit is only set if the image file header was 236 * updated successfully. Therefore it is not required to check the return 237 * value of this function. 238 */ 239 int qcow2_mark_dirty(BlockDriverState *bs) 240 { 241 BDRVQcow2State *s = bs->opaque; 242 uint64_t val; 243 int ret; 244 245 assert(s->qcow_version >= 3); 246 247 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 248 return 0; /* already dirty */ 249 } 250 251 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY); 252 ret = bdrv_pwrite(bs->file, offsetof(QCowHeader, incompatible_features), 253 &val, sizeof(val)); 254 if (ret < 0) { 255 return ret; 256 } 257 ret = bdrv_flush(bs->file->bs); 258 if (ret < 0) { 259 return ret; 260 } 261 262 /* Only treat image as dirty if the header was updated successfully */ 263 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY; 264 return 0; 265 } 266 267 /* 268 * Clears the dirty bit and flushes before if necessary. Only call this 269 * function when there are no pending requests, it does not guard against 270 * concurrent requests dirtying the image. 271 */ 272 static int qcow2_mark_clean(BlockDriverState *bs) 273 { 274 BDRVQcow2State *s = bs->opaque; 275 276 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 277 int ret; 278 279 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY; 280 281 ret = bdrv_flush(bs); 282 if (ret < 0) { 283 return ret; 284 } 285 286 return qcow2_update_header(bs); 287 } 288 return 0; 289 } 290 291 /* 292 * Marks the image as corrupt. 293 */ 294 int qcow2_mark_corrupt(BlockDriverState *bs) 295 { 296 BDRVQcow2State *s = bs->opaque; 297 298 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT; 299 return qcow2_update_header(bs); 300 } 301 302 /* 303 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes 304 * before if necessary. 305 */ 306 int qcow2_mark_consistent(BlockDriverState *bs) 307 { 308 BDRVQcow2State *s = bs->opaque; 309 310 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 311 int ret = bdrv_flush(bs); 312 if (ret < 0) { 313 return ret; 314 } 315 316 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT; 317 return qcow2_update_header(bs); 318 } 319 return 0; 320 } 321 322 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result, 323 BdrvCheckMode fix) 324 { 325 int ret = qcow2_check_refcounts(bs, result, fix); 326 if (ret < 0) { 327 return ret; 328 } 329 330 if (fix && result->check_errors == 0 && result->corruptions == 0) { 331 ret = qcow2_mark_clean(bs); 332 if (ret < 0) { 333 return ret; 334 } 335 return qcow2_mark_consistent(bs); 336 } 337 return ret; 338 } 339 340 static int validate_table_offset(BlockDriverState *bs, uint64_t offset, 341 uint64_t entries, size_t entry_len) 342 { 343 BDRVQcow2State *s = bs->opaque; 344 uint64_t size; 345 346 /* Use signed INT64_MAX as the maximum even for uint64_t header fields, 347 * because values will be passed to qemu functions taking int64_t. */ 348 if (entries > INT64_MAX / entry_len) { 349 return -EINVAL; 350 } 351 352 size = entries * entry_len; 353 354 if (INT64_MAX - size < offset) { 355 return -EINVAL; 356 } 357 358 /* Tables must be cluster aligned */ 359 if (offset & (s->cluster_size - 1)) { 360 return -EINVAL; 361 } 362 363 return 0; 364 } 365 366 static QemuOptsList qcow2_runtime_opts = { 367 .name = "qcow2", 368 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head), 369 .desc = { 370 { 371 .name = QCOW2_OPT_LAZY_REFCOUNTS, 372 .type = QEMU_OPT_BOOL, 373 .help = "Postpone refcount updates", 374 }, 375 { 376 .name = QCOW2_OPT_DISCARD_REQUEST, 377 .type = QEMU_OPT_BOOL, 378 .help = "Pass guest discard requests to the layer below", 379 }, 380 { 381 .name = QCOW2_OPT_DISCARD_SNAPSHOT, 382 .type = QEMU_OPT_BOOL, 383 .help = "Generate discard requests when snapshot related space " 384 "is freed", 385 }, 386 { 387 .name = QCOW2_OPT_DISCARD_OTHER, 388 .type = QEMU_OPT_BOOL, 389 .help = "Generate discard requests when other clusters are freed", 390 }, 391 { 392 .name = QCOW2_OPT_OVERLAP, 393 .type = QEMU_OPT_STRING, 394 .help = "Selects which overlap checks to perform from a range of " 395 "templates (none, constant, cached, all)", 396 }, 397 { 398 .name = QCOW2_OPT_OVERLAP_TEMPLATE, 399 .type = QEMU_OPT_STRING, 400 .help = "Selects which overlap checks to perform from a range of " 401 "templates (none, constant, cached, all)", 402 }, 403 { 404 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER, 405 .type = QEMU_OPT_BOOL, 406 .help = "Check for unintended writes into the main qcow2 header", 407 }, 408 { 409 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1, 410 .type = QEMU_OPT_BOOL, 411 .help = "Check for unintended writes into the active L1 table", 412 }, 413 { 414 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2, 415 .type = QEMU_OPT_BOOL, 416 .help = "Check for unintended writes into an active L2 table", 417 }, 418 { 419 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 420 .type = QEMU_OPT_BOOL, 421 .help = "Check for unintended writes into the refcount table", 422 }, 423 { 424 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 425 .type = QEMU_OPT_BOOL, 426 .help = "Check for unintended writes into a refcount block", 427 }, 428 { 429 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 430 .type = QEMU_OPT_BOOL, 431 .help = "Check for unintended writes into the snapshot table", 432 }, 433 { 434 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1, 435 .type = QEMU_OPT_BOOL, 436 .help = "Check for unintended writes into an inactive L1 table", 437 }, 438 { 439 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2, 440 .type = QEMU_OPT_BOOL, 441 .help = "Check for unintended writes into an inactive L2 table", 442 }, 443 { 444 .name = QCOW2_OPT_CACHE_SIZE, 445 .type = QEMU_OPT_SIZE, 446 .help = "Maximum combined metadata (L2 tables and refcount blocks) " 447 "cache size", 448 }, 449 { 450 .name = QCOW2_OPT_L2_CACHE_SIZE, 451 .type = QEMU_OPT_SIZE, 452 .help = "Maximum L2 table cache size", 453 }, 454 { 455 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE, 456 .type = QEMU_OPT_SIZE, 457 .help = "Maximum refcount block cache size", 458 }, 459 { 460 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL, 461 .type = QEMU_OPT_NUMBER, 462 .help = "Clean unused cache entries after this time (in seconds)", 463 }, 464 { /* end of list */ } 465 }, 466 }; 467 468 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = { 469 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER, 470 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1, 471 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2, 472 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE, 473 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK, 474 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE, 475 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1, 476 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2, 477 }; 478 479 static void cache_clean_timer_cb(void *opaque) 480 { 481 BlockDriverState *bs = opaque; 482 BDRVQcow2State *s = bs->opaque; 483 qcow2_cache_clean_unused(bs, s->l2_table_cache); 484 qcow2_cache_clean_unused(bs, s->refcount_block_cache); 485 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 486 (int64_t) s->cache_clean_interval * 1000); 487 } 488 489 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context) 490 { 491 BDRVQcow2State *s = bs->opaque; 492 if (s->cache_clean_interval > 0) { 493 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL, 494 SCALE_MS, cache_clean_timer_cb, 495 bs); 496 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 497 (int64_t) s->cache_clean_interval * 1000); 498 } 499 } 500 501 static void cache_clean_timer_del(BlockDriverState *bs) 502 { 503 BDRVQcow2State *s = bs->opaque; 504 if (s->cache_clean_timer) { 505 timer_del(s->cache_clean_timer); 506 timer_free(s->cache_clean_timer); 507 s->cache_clean_timer = NULL; 508 } 509 } 510 511 static void qcow2_detach_aio_context(BlockDriverState *bs) 512 { 513 cache_clean_timer_del(bs); 514 } 515 516 static void qcow2_attach_aio_context(BlockDriverState *bs, 517 AioContext *new_context) 518 { 519 cache_clean_timer_init(bs, new_context); 520 } 521 522 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts, 523 uint64_t *l2_cache_size, 524 uint64_t *refcount_cache_size, Error **errp) 525 { 526 BDRVQcow2State *s = bs->opaque; 527 uint64_t combined_cache_size; 528 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set; 529 530 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE); 531 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE); 532 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 533 534 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0); 535 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0); 536 *refcount_cache_size = qemu_opt_get_size(opts, 537 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0); 538 539 if (combined_cache_size_set) { 540 if (l2_cache_size_set && refcount_cache_size_set) { 541 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE 542 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set " 543 "the same time"); 544 return; 545 } else if (*l2_cache_size > combined_cache_size) { 546 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed " 547 QCOW2_OPT_CACHE_SIZE); 548 return; 549 } else if (*refcount_cache_size > combined_cache_size) { 550 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed " 551 QCOW2_OPT_CACHE_SIZE); 552 return; 553 } 554 555 if (l2_cache_size_set) { 556 *refcount_cache_size = combined_cache_size - *l2_cache_size; 557 } else if (refcount_cache_size_set) { 558 *l2_cache_size = combined_cache_size - *refcount_cache_size; 559 } else { 560 *refcount_cache_size = combined_cache_size 561 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1); 562 *l2_cache_size = combined_cache_size - *refcount_cache_size; 563 } 564 } else { 565 if (!l2_cache_size_set && !refcount_cache_size_set) { 566 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE, 567 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS 568 * s->cluster_size); 569 *refcount_cache_size = *l2_cache_size 570 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 571 } else if (!l2_cache_size_set) { 572 *l2_cache_size = *refcount_cache_size 573 * DEFAULT_L2_REFCOUNT_SIZE_RATIO; 574 } else if (!refcount_cache_size_set) { 575 *refcount_cache_size = *l2_cache_size 576 / DEFAULT_L2_REFCOUNT_SIZE_RATIO; 577 } 578 } 579 } 580 581 typedef struct Qcow2ReopenState { 582 Qcow2Cache *l2_table_cache; 583 Qcow2Cache *refcount_block_cache; 584 bool use_lazy_refcounts; 585 int overlap_check; 586 bool discard_passthrough[QCOW2_DISCARD_MAX]; 587 uint64_t cache_clean_interval; 588 } Qcow2ReopenState; 589 590 static int qcow2_update_options_prepare(BlockDriverState *bs, 591 Qcow2ReopenState *r, 592 QDict *options, int flags, 593 Error **errp) 594 { 595 BDRVQcow2State *s = bs->opaque; 596 QemuOpts *opts = NULL; 597 const char *opt_overlap_check, *opt_overlap_check_template; 598 int overlap_check_template = 0; 599 uint64_t l2_cache_size, refcount_cache_size; 600 int i; 601 Error *local_err = NULL; 602 int ret; 603 604 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort); 605 qemu_opts_absorb_qdict(opts, options, &local_err); 606 if (local_err) { 607 error_propagate(errp, local_err); 608 ret = -EINVAL; 609 goto fail; 610 } 611 612 /* get L2 table/refcount block cache size from command line options */ 613 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size, 614 &local_err); 615 if (local_err) { 616 error_propagate(errp, local_err); 617 ret = -EINVAL; 618 goto fail; 619 } 620 621 l2_cache_size /= s->cluster_size; 622 if (l2_cache_size < MIN_L2_CACHE_SIZE) { 623 l2_cache_size = MIN_L2_CACHE_SIZE; 624 } 625 if (l2_cache_size > INT_MAX) { 626 error_setg(errp, "L2 cache size too big"); 627 ret = -EINVAL; 628 goto fail; 629 } 630 631 refcount_cache_size /= s->cluster_size; 632 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) { 633 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE; 634 } 635 if (refcount_cache_size > INT_MAX) { 636 error_setg(errp, "Refcount cache size too big"); 637 ret = -EINVAL; 638 goto fail; 639 } 640 641 /* alloc new L2 table/refcount block cache, flush old one */ 642 if (s->l2_table_cache) { 643 ret = qcow2_cache_flush(bs, s->l2_table_cache); 644 if (ret) { 645 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache"); 646 goto fail; 647 } 648 } 649 650 if (s->refcount_block_cache) { 651 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 652 if (ret) { 653 error_setg_errno(errp, -ret, 654 "Failed to flush the refcount block cache"); 655 goto fail; 656 } 657 } 658 659 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size); 660 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size); 661 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) { 662 error_setg(errp, "Could not allocate metadata caches"); 663 ret = -ENOMEM; 664 goto fail; 665 } 666 667 /* New interval for cache cleanup timer */ 668 r->cache_clean_interval = 669 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL, 670 s->cache_clean_interval); 671 #ifndef CONFIG_LINUX 672 if (r->cache_clean_interval != 0) { 673 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL 674 " not supported on this host"); 675 ret = -EINVAL; 676 goto fail; 677 } 678 #endif 679 if (r->cache_clean_interval > UINT_MAX) { 680 error_setg(errp, "Cache clean interval too big"); 681 ret = -EINVAL; 682 goto fail; 683 } 684 685 /* lazy-refcounts; flush if going from enabled to disabled */ 686 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS, 687 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)); 688 if (r->use_lazy_refcounts && s->qcow_version < 3) { 689 error_setg(errp, "Lazy refcounts require a qcow2 image with at least " 690 "qemu 1.1 compatibility level"); 691 ret = -EINVAL; 692 goto fail; 693 } 694 695 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) { 696 ret = qcow2_mark_clean(bs); 697 if (ret < 0) { 698 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts"); 699 goto fail; 700 } 701 } 702 703 /* Overlap check options */ 704 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP); 705 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE); 706 if (opt_overlap_check_template && opt_overlap_check && 707 strcmp(opt_overlap_check_template, opt_overlap_check)) 708 { 709 error_setg(errp, "Conflicting values for qcow2 options '" 710 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE 711 "' ('%s')", opt_overlap_check, opt_overlap_check_template); 712 ret = -EINVAL; 713 goto fail; 714 } 715 if (!opt_overlap_check) { 716 opt_overlap_check = opt_overlap_check_template ?: "cached"; 717 } 718 719 if (!strcmp(opt_overlap_check, "none")) { 720 overlap_check_template = 0; 721 } else if (!strcmp(opt_overlap_check, "constant")) { 722 overlap_check_template = QCOW2_OL_CONSTANT; 723 } else if (!strcmp(opt_overlap_check, "cached")) { 724 overlap_check_template = QCOW2_OL_CACHED; 725 } else if (!strcmp(opt_overlap_check, "all")) { 726 overlap_check_template = QCOW2_OL_ALL; 727 } else { 728 error_setg(errp, "Unsupported value '%s' for qcow2 option " 729 "'overlap-check'. Allowed are any of the following: " 730 "none, constant, cached, all", opt_overlap_check); 731 ret = -EINVAL; 732 goto fail; 733 } 734 735 r->overlap_check = 0; 736 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) { 737 /* overlap-check defines a template bitmask, but every flag may be 738 * overwritten through the associated boolean option */ 739 r->overlap_check |= 740 qemu_opt_get_bool(opts, overlap_bool_option_names[i], 741 overlap_check_template & (1 << i)) << i; 742 } 743 744 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false; 745 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true; 746 r->discard_passthrough[QCOW2_DISCARD_REQUEST] = 747 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST, 748 flags & BDRV_O_UNMAP); 749 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] = 750 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true); 751 r->discard_passthrough[QCOW2_DISCARD_OTHER] = 752 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false); 753 754 ret = 0; 755 fail: 756 qemu_opts_del(opts); 757 opts = NULL; 758 return ret; 759 } 760 761 static void qcow2_update_options_commit(BlockDriverState *bs, 762 Qcow2ReopenState *r) 763 { 764 BDRVQcow2State *s = bs->opaque; 765 int i; 766 767 if (s->l2_table_cache) { 768 qcow2_cache_destroy(bs, s->l2_table_cache); 769 } 770 if (s->refcount_block_cache) { 771 qcow2_cache_destroy(bs, s->refcount_block_cache); 772 } 773 s->l2_table_cache = r->l2_table_cache; 774 s->refcount_block_cache = r->refcount_block_cache; 775 776 s->overlap_check = r->overlap_check; 777 s->use_lazy_refcounts = r->use_lazy_refcounts; 778 779 for (i = 0; i < QCOW2_DISCARD_MAX; i++) { 780 s->discard_passthrough[i] = r->discard_passthrough[i]; 781 } 782 783 if (s->cache_clean_interval != r->cache_clean_interval) { 784 cache_clean_timer_del(bs); 785 s->cache_clean_interval = r->cache_clean_interval; 786 cache_clean_timer_init(bs, bdrv_get_aio_context(bs)); 787 } 788 } 789 790 static void qcow2_update_options_abort(BlockDriverState *bs, 791 Qcow2ReopenState *r) 792 { 793 if (r->l2_table_cache) { 794 qcow2_cache_destroy(bs, r->l2_table_cache); 795 } 796 if (r->refcount_block_cache) { 797 qcow2_cache_destroy(bs, r->refcount_block_cache); 798 } 799 } 800 801 static int qcow2_update_options(BlockDriverState *bs, QDict *options, 802 int flags, Error **errp) 803 { 804 Qcow2ReopenState r = {}; 805 int ret; 806 807 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp); 808 if (ret >= 0) { 809 qcow2_update_options_commit(bs, &r); 810 } else { 811 qcow2_update_options_abort(bs, &r); 812 } 813 814 return ret; 815 } 816 817 static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, 818 Error **errp) 819 { 820 BDRVQcow2State *s = bs->opaque; 821 unsigned int len, i; 822 int ret = 0; 823 QCowHeader header; 824 Error *local_err = NULL; 825 uint64_t ext_end; 826 uint64_t l1_vm_state_index; 827 828 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 829 if (ret < 0) { 830 error_setg_errno(errp, -ret, "Could not read qcow2 header"); 831 goto fail; 832 } 833 be32_to_cpus(&header.magic); 834 be32_to_cpus(&header.version); 835 be64_to_cpus(&header.backing_file_offset); 836 be32_to_cpus(&header.backing_file_size); 837 be64_to_cpus(&header.size); 838 be32_to_cpus(&header.cluster_bits); 839 be32_to_cpus(&header.crypt_method); 840 be64_to_cpus(&header.l1_table_offset); 841 be32_to_cpus(&header.l1_size); 842 be64_to_cpus(&header.refcount_table_offset); 843 be32_to_cpus(&header.refcount_table_clusters); 844 be64_to_cpus(&header.snapshots_offset); 845 be32_to_cpus(&header.nb_snapshots); 846 847 if (header.magic != QCOW_MAGIC) { 848 error_setg(errp, "Image is not in qcow2 format"); 849 ret = -EINVAL; 850 goto fail; 851 } 852 if (header.version < 2 || header.version > 3) { 853 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version); 854 ret = -ENOTSUP; 855 goto fail; 856 } 857 858 s->qcow_version = header.version; 859 860 /* Initialise cluster size */ 861 if (header.cluster_bits < MIN_CLUSTER_BITS || 862 header.cluster_bits > MAX_CLUSTER_BITS) { 863 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32, 864 header.cluster_bits); 865 ret = -EINVAL; 866 goto fail; 867 } 868 869 s->cluster_bits = header.cluster_bits; 870 s->cluster_size = 1 << s->cluster_bits; 871 s->cluster_sectors = 1 << (s->cluster_bits - 9); 872 873 /* Initialise version 3 header fields */ 874 if (header.version == 2) { 875 header.incompatible_features = 0; 876 header.compatible_features = 0; 877 header.autoclear_features = 0; 878 header.refcount_order = 4; 879 header.header_length = 72; 880 } else { 881 be64_to_cpus(&header.incompatible_features); 882 be64_to_cpus(&header.compatible_features); 883 be64_to_cpus(&header.autoclear_features); 884 be32_to_cpus(&header.refcount_order); 885 be32_to_cpus(&header.header_length); 886 887 if (header.header_length < 104) { 888 error_setg(errp, "qcow2 header too short"); 889 ret = -EINVAL; 890 goto fail; 891 } 892 } 893 894 if (header.header_length > s->cluster_size) { 895 error_setg(errp, "qcow2 header exceeds cluster size"); 896 ret = -EINVAL; 897 goto fail; 898 } 899 900 if (header.header_length > sizeof(header)) { 901 s->unknown_header_fields_size = header.header_length - sizeof(header); 902 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size); 903 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields, 904 s->unknown_header_fields_size); 905 if (ret < 0) { 906 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header " 907 "fields"); 908 goto fail; 909 } 910 } 911 912 if (header.backing_file_offset > s->cluster_size) { 913 error_setg(errp, "Invalid backing file offset"); 914 ret = -EINVAL; 915 goto fail; 916 } 917 918 if (header.backing_file_offset) { 919 ext_end = header.backing_file_offset; 920 } else { 921 ext_end = 1 << header.cluster_bits; 922 } 923 924 /* Handle feature bits */ 925 s->incompatible_features = header.incompatible_features; 926 s->compatible_features = header.compatible_features; 927 s->autoclear_features = header.autoclear_features; 928 929 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) { 930 void *feature_table = NULL; 931 qcow2_read_extensions(bs, header.header_length, ext_end, 932 &feature_table, NULL); 933 report_unsupported_feature(errp, feature_table, 934 s->incompatible_features & 935 ~QCOW2_INCOMPAT_MASK); 936 ret = -ENOTSUP; 937 g_free(feature_table); 938 goto fail; 939 } 940 941 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) { 942 /* Corrupt images may not be written to unless they are being repaired 943 */ 944 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) { 945 error_setg(errp, "qcow2: Image is corrupt; cannot be opened " 946 "read/write"); 947 ret = -EACCES; 948 goto fail; 949 } 950 } 951 952 /* Check support for various header values */ 953 if (header.refcount_order > 6) { 954 error_setg(errp, "Reference count entry width too large; may not " 955 "exceed 64 bits"); 956 ret = -EINVAL; 957 goto fail; 958 } 959 s->refcount_order = header.refcount_order; 960 s->refcount_bits = 1 << s->refcount_order; 961 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1); 962 s->refcount_max += s->refcount_max - 1; 963 964 if (header.crypt_method > QCOW_CRYPT_AES) { 965 error_setg(errp, "Unsupported encryption method: %" PRIu32, 966 header.crypt_method); 967 ret = -EINVAL; 968 goto fail; 969 } 970 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128, 971 QCRYPTO_CIPHER_MODE_CBC)) { 972 error_setg(errp, "AES cipher not available"); 973 ret = -EINVAL; 974 goto fail; 975 } 976 s->crypt_method_header = header.crypt_method; 977 if (s->crypt_method_header) { 978 if (bdrv_uses_whitelist() && 979 s->crypt_method_header == QCOW_CRYPT_AES) { 980 error_setg(errp, 981 "Use of AES-CBC encrypted qcow2 images is no longer " 982 "supported in system emulators"); 983 error_append_hint(errp, 984 "You can use 'qemu-img convert' to convert your " 985 "image to an alternative supported format, such " 986 "as unencrypted qcow2, or raw with the LUKS " 987 "format instead.\n"); 988 ret = -ENOSYS; 989 goto fail; 990 } 991 992 bs->encrypted = true; 993 } 994 995 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ 996 s->l2_size = 1 << s->l2_bits; 997 /* 2^(s->refcount_order - 3) is the refcount width in bytes */ 998 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); 999 s->refcount_block_size = 1 << s->refcount_block_bits; 1000 bs->total_sectors = header.size / 512; 1001 s->csize_shift = (62 - (s->cluster_bits - 8)); 1002 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; 1003 s->cluster_offset_mask = (1LL << s->csize_shift) - 1; 1004 1005 s->refcount_table_offset = header.refcount_table_offset; 1006 s->refcount_table_size = 1007 header.refcount_table_clusters << (s->cluster_bits - 3); 1008 1009 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) { 1010 error_setg(errp, "Reference count table too large"); 1011 ret = -EINVAL; 1012 goto fail; 1013 } 1014 1015 ret = validate_table_offset(bs, s->refcount_table_offset, 1016 s->refcount_table_size, sizeof(uint64_t)); 1017 if (ret < 0) { 1018 error_setg(errp, "Invalid reference count table offset"); 1019 goto fail; 1020 } 1021 1022 /* Snapshot table offset/length */ 1023 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) { 1024 error_setg(errp, "Too many snapshots"); 1025 ret = -EINVAL; 1026 goto fail; 1027 } 1028 1029 ret = validate_table_offset(bs, header.snapshots_offset, 1030 header.nb_snapshots, 1031 sizeof(QCowSnapshotHeader)); 1032 if (ret < 0) { 1033 error_setg(errp, "Invalid snapshot table offset"); 1034 goto fail; 1035 } 1036 1037 /* read the level 1 table */ 1038 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) { 1039 error_setg(errp, "Active L1 table too large"); 1040 ret = -EFBIG; 1041 goto fail; 1042 } 1043 s->l1_size = header.l1_size; 1044 1045 l1_vm_state_index = size_to_l1(s, header.size); 1046 if (l1_vm_state_index > INT_MAX) { 1047 error_setg(errp, "Image is too big"); 1048 ret = -EFBIG; 1049 goto fail; 1050 } 1051 s->l1_vm_state_index = l1_vm_state_index; 1052 1053 /* the L1 table must contain at least enough entries to put 1054 header.size bytes */ 1055 if (s->l1_size < s->l1_vm_state_index) { 1056 error_setg(errp, "L1 table is too small"); 1057 ret = -EINVAL; 1058 goto fail; 1059 } 1060 1061 ret = validate_table_offset(bs, header.l1_table_offset, 1062 header.l1_size, sizeof(uint64_t)); 1063 if (ret < 0) { 1064 error_setg(errp, "Invalid L1 table offset"); 1065 goto fail; 1066 } 1067 s->l1_table_offset = header.l1_table_offset; 1068 1069 1070 if (s->l1_size > 0) { 1071 s->l1_table = qemu_try_blockalign(bs->file->bs, 1072 align_offset(s->l1_size * sizeof(uint64_t), 512)); 1073 if (s->l1_table == NULL) { 1074 error_setg(errp, "Could not allocate L1 table"); 1075 ret = -ENOMEM; 1076 goto fail; 1077 } 1078 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 1079 s->l1_size * sizeof(uint64_t)); 1080 if (ret < 0) { 1081 error_setg_errno(errp, -ret, "Could not read L1 table"); 1082 goto fail; 1083 } 1084 for(i = 0;i < s->l1_size; i++) { 1085 be64_to_cpus(&s->l1_table[i]); 1086 } 1087 } 1088 1089 /* Parse driver-specific options */ 1090 ret = qcow2_update_options(bs, options, flags, errp); 1091 if (ret < 0) { 1092 goto fail; 1093 } 1094 1095 s->cluster_cache = g_malloc(s->cluster_size); 1096 /* one more sector for decompressed data alignment */ 1097 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS 1098 * s->cluster_size + 512); 1099 if (s->cluster_data == NULL) { 1100 error_setg(errp, "Could not allocate temporary cluster buffer"); 1101 ret = -ENOMEM; 1102 goto fail; 1103 } 1104 1105 s->cluster_cache_offset = -1; 1106 s->flags = flags; 1107 1108 ret = qcow2_refcount_init(bs); 1109 if (ret != 0) { 1110 error_setg_errno(errp, -ret, "Could not initialize refcount handling"); 1111 goto fail; 1112 } 1113 1114 QLIST_INIT(&s->cluster_allocs); 1115 QTAILQ_INIT(&s->discards); 1116 1117 /* read qcow2 extensions */ 1118 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL, 1119 &local_err)) { 1120 error_propagate(errp, local_err); 1121 ret = -EINVAL; 1122 goto fail; 1123 } 1124 1125 /* read the backing file name */ 1126 if (header.backing_file_offset != 0) { 1127 len = header.backing_file_size; 1128 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) || 1129 len >= sizeof(bs->backing_file)) { 1130 error_setg(errp, "Backing file name too long"); 1131 ret = -EINVAL; 1132 goto fail; 1133 } 1134 ret = bdrv_pread(bs->file, header.backing_file_offset, 1135 bs->backing_file, len); 1136 if (ret < 0) { 1137 error_setg_errno(errp, -ret, "Could not read backing file name"); 1138 goto fail; 1139 } 1140 bs->backing_file[len] = '\0'; 1141 s->image_backing_file = g_strdup(bs->backing_file); 1142 } 1143 1144 /* Internal snapshots */ 1145 s->snapshots_offset = header.snapshots_offset; 1146 s->nb_snapshots = header.nb_snapshots; 1147 1148 ret = qcow2_read_snapshots(bs); 1149 if (ret < 0) { 1150 error_setg_errno(errp, -ret, "Could not read snapshots"); 1151 goto fail; 1152 } 1153 1154 /* Clear unknown autoclear feature bits */ 1155 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) { 1156 s->autoclear_features = 0; 1157 ret = qcow2_update_header(bs); 1158 if (ret < 0) { 1159 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 1160 goto fail; 1161 } 1162 } 1163 1164 /* Initialise locks */ 1165 qemu_co_mutex_init(&s->lock); 1166 bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP; 1167 1168 /* Repair image if dirty */ 1169 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only && 1170 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) { 1171 BdrvCheckResult result = {0}; 1172 1173 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS); 1174 if (ret < 0) { 1175 error_setg_errno(errp, -ret, "Could not repair dirty image"); 1176 goto fail; 1177 } 1178 } 1179 1180 #ifdef DEBUG_ALLOC 1181 { 1182 BdrvCheckResult result = {0}; 1183 qcow2_check_refcounts(bs, &result, 0); 1184 } 1185 #endif 1186 return ret; 1187 1188 fail: 1189 g_free(s->unknown_header_fields); 1190 cleanup_unknown_header_ext(bs); 1191 qcow2_free_snapshots(bs); 1192 qcow2_refcount_close(bs); 1193 qemu_vfree(s->l1_table); 1194 /* else pre-write overlap checks in cache_destroy may crash */ 1195 s->l1_table = NULL; 1196 cache_clean_timer_del(bs); 1197 if (s->l2_table_cache) { 1198 qcow2_cache_destroy(bs, s->l2_table_cache); 1199 } 1200 if (s->refcount_block_cache) { 1201 qcow2_cache_destroy(bs, s->refcount_block_cache); 1202 } 1203 g_free(s->cluster_cache); 1204 qemu_vfree(s->cluster_data); 1205 return ret; 1206 } 1207 1208 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, 1209 Error **errp) 1210 { 1211 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 1212 false, errp); 1213 if (!bs->file) { 1214 return -EINVAL; 1215 } 1216 1217 return qcow2_do_open(bs, options, flags, errp); 1218 } 1219 1220 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) 1221 { 1222 BDRVQcow2State *s = bs->opaque; 1223 1224 if (bs->encrypted) { 1225 /* Encryption works on a sector granularity */ 1226 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 1227 } 1228 bs->bl.pwrite_zeroes_alignment = s->cluster_size; 1229 bs->bl.pdiscard_alignment = s->cluster_size; 1230 } 1231 1232 static int qcow2_set_key(BlockDriverState *bs, const char *key) 1233 { 1234 BDRVQcow2State *s = bs->opaque; 1235 uint8_t keybuf[16]; 1236 int len, i; 1237 Error *err = NULL; 1238 1239 memset(keybuf, 0, 16); 1240 len = strlen(key); 1241 if (len > 16) 1242 len = 16; 1243 /* XXX: we could compress the chars to 7 bits to increase 1244 entropy */ 1245 for(i = 0;i < len;i++) { 1246 keybuf[i] = key[i]; 1247 } 1248 assert(bs->encrypted); 1249 1250 qcrypto_cipher_free(s->cipher); 1251 s->cipher = qcrypto_cipher_new( 1252 QCRYPTO_CIPHER_ALG_AES_128, 1253 QCRYPTO_CIPHER_MODE_CBC, 1254 keybuf, G_N_ELEMENTS(keybuf), 1255 &err); 1256 1257 if (!s->cipher) { 1258 /* XXX would be nice if errors in this method could 1259 * be properly propagate to the caller. Would need 1260 * the bdrv_set_key() API signature to be fixed. */ 1261 error_free(err); 1262 return -1; 1263 } 1264 return 0; 1265 } 1266 1267 static int qcow2_reopen_prepare(BDRVReopenState *state, 1268 BlockReopenQueue *queue, Error **errp) 1269 { 1270 Qcow2ReopenState *r; 1271 int ret; 1272 1273 r = g_new0(Qcow2ReopenState, 1); 1274 state->opaque = r; 1275 1276 ret = qcow2_update_options_prepare(state->bs, r, state->options, 1277 state->flags, errp); 1278 if (ret < 0) { 1279 goto fail; 1280 } 1281 1282 /* We need to write out any unwritten data if we reopen read-only. */ 1283 if ((state->flags & BDRV_O_RDWR) == 0) { 1284 ret = bdrv_flush(state->bs); 1285 if (ret < 0) { 1286 goto fail; 1287 } 1288 1289 ret = qcow2_mark_clean(state->bs); 1290 if (ret < 0) { 1291 goto fail; 1292 } 1293 } 1294 1295 return 0; 1296 1297 fail: 1298 qcow2_update_options_abort(state->bs, r); 1299 g_free(r); 1300 return ret; 1301 } 1302 1303 static void qcow2_reopen_commit(BDRVReopenState *state) 1304 { 1305 qcow2_update_options_commit(state->bs, state->opaque); 1306 g_free(state->opaque); 1307 } 1308 1309 static void qcow2_reopen_abort(BDRVReopenState *state) 1310 { 1311 qcow2_update_options_abort(state->bs, state->opaque); 1312 g_free(state->opaque); 1313 } 1314 1315 static void qcow2_join_options(QDict *options, QDict *old_options) 1316 { 1317 bool has_new_overlap_template = 1318 qdict_haskey(options, QCOW2_OPT_OVERLAP) || 1319 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE); 1320 bool has_new_total_cache_size = 1321 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE); 1322 bool has_all_cache_options; 1323 1324 /* New overlap template overrides all old overlap options */ 1325 if (has_new_overlap_template) { 1326 qdict_del(old_options, QCOW2_OPT_OVERLAP); 1327 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE); 1328 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER); 1329 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1); 1330 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2); 1331 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE); 1332 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK); 1333 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE); 1334 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1); 1335 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2); 1336 } 1337 1338 /* New total cache size overrides all old options */ 1339 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) { 1340 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE); 1341 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1342 } 1343 1344 qdict_join(options, old_options, false); 1345 1346 /* 1347 * If after merging all cache size options are set, an old total size is 1348 * overwritten. Do keep all options, however, if all three are new. The 1349 * resulting error message is what we want to happen. 1350 */ 1351 has_all_cache_options = 1352 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) || 1353 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) || 1354 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE); 1355 1356 if (has_all_cache_options && !has_new_total_cache_size) { 1357 qdict_del(options, QCOW2_OPT_CACHE_SIZE); 1358 } 1359 } 1360 1361 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs, 1362 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 1363 { 1364 BDRVQcow2State *s = bs->opaque; 1365 uint64_t cluster_offset; 1366 int index_in_cluster, ret; 1367 unsigned int bytes; 1368 int64_t status = 0; 1369 1370 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE); 1371 qemu_co_mutex_lock(&s->lock); 1372 ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes, 1373 &cluster_offset); 1374 qemu_co_mutex_unlock(&s->lock); 1375 if (ret < 0) { 1376 return ret; 1377 } 1378 1379 *pnum = bytes >> BDRV_SECTOR_BITS; 1380 1381 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED && 1382 !s->cipher) { 1383 index_in_cluster = sector_num & (s->cluster_sectors - 1); 1384 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 1385 *file = bs->file->bs; 1386 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset; 1387 } 1388 if (ret == QCOW2_CLUSTER_ZERO_PLAIN || ret == QCOW2_CLUSTER_ZERO_ALLOC) { 1389 status |= BDRV_BLOCK_ZERO; 1390 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) { 1391 status |= BDRV_BLOCK_DATA; 1392 } 1393 return status; 1394 } 1395 1396 /* handle reading after the end of the backing file */ 1397 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 1398 int64_t offset, int bytes) 1399 { 1400 uint64_t bs_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1401 int n1; 1402 1403 if ((offset + bytes) <= bs_size) { 1404 return bytes; 1405 } 1406 1407 if (offset >= bs_size) { 1408 n1 = 0; 1409 } else { 1410 n1 = bs_size - offset; 1411 } 1412 1413 qemu_iovec_memset(qiov, n1, 0, bytes - n1); 1414 1415 return n1; 1416 } 1417 1418 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, 1419 uint64_t bytes, QEMUIOVector *qiov, 1420 int flags) 1421 { 1422 BDRVQcow2State *s = bs->opaque; 1423 int offset_in_cluster, n1; 1424 int ret; 1425 unsigned int cur_bytes; /* number of bytes in current iteration */ 1426 uint64_t cluster_offset = 0; 1427 uint64_t bytes_done = 0; 1428 QEMUIOVector hd_qiov; 1429 uint8_t *cluster_data = NULL; 1430 1431 qemu_iovec_init(&hd_qiov, qiov->niov); 1432 1433 qemu_co_mutex_lock(&s->lock); 1434 1435 while (bytes != 0) { 1436 1437 /* prepare next request */ 1438 cur_bytes = MIN(bytes, INT_MAX); 1439 if (s->cipher) { 1440 cur_bytes = MIN(cur_bytes, 1441 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1442 } 1443 1444 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); 1445 if (ret < 0) { 1446 goto fail; 1447 } 1448 1449 offset_in_cluster = offset_into_cluster(s, offset); 1450 1451 qemu_iovec_reset(&hd_qiov); 1452 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1453 1454 switch (ret) { 1455 case QCOW2_CLUSTER_UNALLOCATED: 1456 1457 if (bs->backing) { 1458 /* read from the base image */ 1459 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, 1460 offset, cur_bytes); 1461 if (n1 > 0) { 1462 QEMUIOVector local_qiov; 1463 1464 qemu_iovec_init(&local_qiov, hd_qiov.niov); 1465 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1); 1466 1467 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 1468 qemu_co_mutex_unlock(&s->lock); 1469 ret = bdrv_co_preadv(bs->backing, offset, n1, 1470 &local_qiov, 0); 1471 qemu_co_mutex_lock(&s->lock); 1472 1473 qemu_iovec_destroy(&local_qiov); 1474 1475 if (ret < 0) { 1476 goto fail; 1477 } 1478 } 1479 } else { 1480 /* Note: in this case, no need to wait */ 1481 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1482 } 1483 break; 1484 1485 case QCOW2_CLUSTER_ZERO_PLAIN: 1486 case QCOW2_CLUSTER_ZERO_ALLOC: 1487 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes); 1488 break; 1489 1490 case QCOW2_CLUSTER_COMPRESSED: 1491 /* add AIO support for compressed blocks ? */ 1492 ret = qcow2_decompress_cluster(bs, cluster_offset); 1493 if (ret < 0) { 1494 goto fail; 1495 } 1496 1497 qemu_iovec_from_buf(&hd_qiov, 0, 1498 s->cluster_cache + offset_in_cluster, 1499 cur_bytes); 1500 break; 1501 1502 case QCOW2_CLUSTER_NORMAL: 1503 if ((cluster_offset & 511) != 0) { 1504 ret = -EIO; 1505 goto fail; 1506 } 1507 1508 if (bs->encrypted) { 1509 assert(s->cipher); 1510 1511 /* 1512 * For encrypted images, read everything into a temporary 1513 * contiguous buffer on which the AES functions can work. 1514 */ 1515 if (!cluster_data) { 1516 cluster_data = 1517 qemu_try_blockalign(bs->file->bs, 1518 QCOW_MAX_CRYPT_CLUSTERS 1519 * s->cluster_size); 1520 if (cluster_data == NULL) { 1521 ret = -ENOMEM; 1522 goto fail; 1523 } 1524 } 1525 1526 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1527 qemu_iovec_reset(&hd_qiov); 1528 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1529 } 1530 1531 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 1532 qemu_co_mutex_unlock(&s->lock); 1533 ret = bdrv_co_preadv(bs->file, 1534 cluster_offset + offset_in_cluster, 1535 cur_bytes, &hd_qiov, 0); 1536 qemu_co_mutex_lock(&s->lock); 1537 if (ret < 0) { 1538 goto fail; 1539 } 1540 if (bs->encrypted) { 1541 assert(s->cipher); 1542 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); 1543 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0); 1544 Error *err = NULL; 1545 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS, 1546 cluster_data, cluster_data, 1547 cur_bytes >> BDRV_SECTOR_BITS, 1548 false, &err) < 0) { 1549 error_free(err); 1550 ret = -EIO; 1551 goto fail; 1552 } 1553 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes); 1554 } 1555 break; 1556 1557 default: 1558 g_assert_not_reached(); 1559 ret = -EIO; 1560 goto fail; 1561 } 1562 1563 bytes -= cur_bytes; 1564 offset += cur_bytes; 1565 bytes_done += cur_bytes; 1566 } 1567 ret = 0; 1568 1569 fail: 1570 qemu_co_mutex_unlock(&s->lock); 1571 1572 qemu_iovec_destroy(&hd_qiov); 1573 qemu_vfree(cluster_data); 1574 1575 return ret; 1576 } 1577 1578 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset, 1579 uint64_t bytes, QEMUIOVector *qiov, 1580 int flags) 1581 { 1582 BDRVQcow2State *s = bs->opaque; 1583 int offset_in_cluster; 1584 int ret; 1585 unsigned int cur_bytes; /* number of sectors in current iteration */ 1586 uint64_t cluster_offset; 1587 QEMUIOVector hd_qiov; 1588 uint64_t bytes_done = 0; 1589 uint8_t *cluster_data = NULL; 1590 QCowL2Meta *l2meta = NULL; 1591 1592 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes); 1593 1594 qemu_iovec_init(&hd_qiov, qiov->niov); 1595 1596 s->cluster_cache_offset = -1; /* disable compressed cache */ 1597 1598 qemu_co_mutex_lock(&s->lock); 1599 1600 while (bytes != 0) { 1601 1602 l2meta = NULL; 1603 1604 trace_qcow2_writev_start_part(qemu_coroutine_self()); 1605 offset_in_cluster = offset_into_cluster(s, offset); 1606 cur_bytes = MIN(bytes, INT_MAX); 1607 if (bs->encrypted) { 1608 cur_bytes = MIN(cur_bytes, 1609 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size 1610 - offset_in_cluster); 1611 } 1612 1613 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 1614 &cluster_offset, &l2meta); 1615 if (ret < 0) { 1616 goto fail; 1617 } 1618 1619 assert((cluster_offset & 511) == 0); 1620 1621 qemu_iovec_reset(&hd_qiov); 1622 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes); 1623 1624 if (bs->encrypted) { 1625 Error *err = NULL; 1626 assert(s->cipher); 1627 if (!cluster_data) { 1628 cluster_data = qemu_try_blockalign(bs->file->bs, 1629 QCOW_MAX_CRYPT_CLUSTERS 1630 * s->cluster_size); 1631 if (cluster_data == NULL) { 1632 ret = -ENOMEM; 1633 goto fail; 1634 } 1635 } 1636 1637 assert(hd_qiov.size <= 1638 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); 1639 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size); 1640 1641 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS, 1642 cluster_data, cluster_data, 1643 cur_bytes >>BDRV_SECTOR_BITS, 1644 true, &err) < 0) { 1645 error_free(err); 1646 ret = -EIO; 1647 goto fail; 1648 } 1649 1650 qemu_iovec_reset(&hd_qiov); 1651 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes); 1652 } 1653 1654 ret = qcow2_pre_write_overlap_check(bs, 0, 1655 cluster_offset + offset_in_cluster, cur_bytes); 1656 if (ret < 0) { 1657 goto fail; 1658 } 1659 1660 qemu_co_mutex_unlock(&s->lock); 1661 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 1662 trace_qcow2_writev_data(qemu_coroutine_self(), 1663 cluster_offset + offset_in_cluster); 1664 ret = bdrv_co_pwritev(bs->file, 1665 cluster_offset + offset_in_cluster, 1666 cur_bytes, &hd_qiov, 0); 1667 qemu_co_mutex_lock(&s->lock); 1668 if (ret < 0) { 1669 goto fail; 1670 } 1671 1672 while (l2meta != NULL) { 1673 QCowL2Meta *next; 1674 1675 ret = qcow2_alloc_cluster_link_l2(bs, l2meta); 1676 if (ret < 0) { 1677 goto fail; 1678 } 1679 1680 /* Take the request off the list of running requests */ 1681 if (l2meta->nb_clusters != 0) { 1682 QLIST_REMOVE(l2meta, next_in_flight); 1683 } 1684 1685 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1686 1687 next = l2meta->next; 1688 g_free(l2meta); 1689 l2meta = next; 1690 } 1691 1692 bytes -= cur_bytes; 1693 offset += cur_bytes; 1694 bytes_done += cur_bytes; 1695 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes); 1696 } 1697 ret = 0; 1698 1699 fail: 1700 qemu_co_mutex_unlock(&s->lock); 1701 1702 while (l2meta != NULL) { 1703 QCowL2Meta *next; 1704 1705 if (l2meta->nb_clusters != 0) { 1706 QLIST_REMOVE(l2meta, next_in_flight); 1707 } 1708 qemu_co_queue_restart_all(&l2meta->dependent_requests); 1709 1710 next = l2meta->next; 1711 g_free(l2meta); 1712 l2meta = next; 1713 } 1714 1715 qemu_iovec_destroy(&hd_qiov); 1716 qemu_vfree(cluster_data); 1717 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret); 1718 1719 return ret; 1720 } 1721 1722 static int qcow2_inactivate(BlockDriverState *bs) 1723 { 1724 BDRVQcow2State *s = bs->opaque; 1725 int ret, result = 0; 1726 1727 ret = qcow2_cache_flush(bs, s->l2_table_cache); 1728 if (ret) { 1729 result = ret; 1730 error_report("Failed to flush the L2 table cache: %s", 1731 strerror(-ret)); 1732 } 1733 1734 ret = qcow2_cache_flush(bs, s->refcount_block_cache); 1735 if (ret) { 1736 result = ret; 1737 error_report("Failed to flush the refcount block cache: %s", 1738 strerror(-ret)); 1739 } 1740 1741 if (result == 0) { 1742 qcow2_mark_clean(bs); 1743 } 1744 1745 return result; 1746 } 1747 1748 static void qcow2_close(BlockDriverState *bs) 1749 { 1750 BDRVQcow2State *s = bs->opaque; 1751 qemu_vfree(s->l1_table); 1752 /* else pre-write overlap checks in cache_destroy may crash */ 1753 s->l1_table = NULL; 1754 1755 if (!(s->flags & BDRV_O_INACTIVE)) { 1756 qcow2_inactivate(bs); 1757 } 1758 1759 cache_clean_timer_del(bs); 1760 qcow2_cache_destroy(bs, s->l2_table_cache); 1761 qcow2_cache_destroy(bs, s->refcount_block_cache); 1762 1763 qcrypto_cipher_free(s->cipher); 1764 s->cipher = NULL; 1765 1766 g_free(s->unknown_header_fields); 1767 cleanup_unknown_header_ext(bs); 1768 1769 g_free(s->image_backing_file); 1770 g_free(s->image_backing_format); 1771 1772 g_free(s->cluster_cache); 1773 qemu_vfree(s->cluster_data); 1774 qcow2_refcount_close(bs); 1775 qcow2_free_snapshots(bs); 1776 } 1777 1778 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp) 1779 { 1780 BDRVQcow2State *s = bs->opaque; 1781 int flags = s->flags; 1782 QCryptoCipher *cipher = NULL; 1783 QDict *options; 1784 Error *local_err = NULL; 1785 int ret; 1786 1787 /* 1788 * Backing files are read-only which makes all of their metadata immutable, 1789 * that means we don't have to worry about reopening them here. 1790 */ 1791 1792 cipher = s->cipher; 1793 s->cipher = NULL; 1794 1795 qcow2_close(bs); 1796 1797 memset(s, 0, sizeof(BDRVQcow2State)); 1798 options = qdict_clone_shallow(bs->options); 1799 1800 flags &= ~BDRV_O_INACTIVE; 1801 ret = qcow2_do_open(bs, options, flags, &local_err); 1802 QDECREF(options); 1803 if (local_err) { 1804 error_propagate(errp, local_err); 1805 error_prepend(errp, "Could not reopen qcow2 layer: "); 1806 bs->drv = NULL; 1807 return; 1808 } else if (ret < 0) { 1809 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer"); 1810 bs->drv = NULL; 1811 return; 1812 } 1813 1814 s->cipher = cipher; 1815 } 1816 1817 static size_t header_ext_add(char *buf, uint32_t magic, const void *s, 1818 size_t len, size_t buflen) 1819 { 1820 QCowExtension *ext_backing_fmt = (QCowExtension*) buf; 1821 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7); 1822 1823 if (buflen < ext_len) { 1824 return -ENOSPC; 1825 } 1826 1827 *ext_backing_fmt = (QCowExtension) { 1828 .magic = cpu_to_be32(magic), 1829 .len = cpu_to_be32(len), 1830 }; 1831 1832 if (len) { 1833 memcpy(buf + sizeof(QCowExtension), s, len); 1834 } 1835 1836 return ext_len; 1837 } 1838 1839 /* 1840 * Updates the qcow2 header, including the variable length parts of it, i.e. 1841 * the backing file name and all extensions. qcow2 was not designed to allow 1842 * such changes, so if we run out of space (we can only use the first cluster) 1843 * this function may fail. 1844 * 1845 * Returns 0 on success, -errno in error cases. 1846 */ 1847 int qcow2_update_header(BlockDriverState *bs) 1848 { 1849 BDRVQcow2State *s = bs->opaque; 1850 QCowHeader *header; 1851 char *buf; 1852 size_t buflen = s->cluster_size; 1853 int ret; 1854 uint64_t total_size; 1855 uint32_t refcount_table_clusters; 1856 size_t header_length; 1857 Qcow2UnknownHeaderExtension *uext; 1858 1859 buf = qemu_blockalign(bs, buflen); 1860 1861 /* Header structure */ 1862 header = (QCowHeader*) buf; 1863 1864 if (buflen < sizeof(*header)) { 1865 ret = -ENOSPC; 1866 goto fail; 1867 } 1868 1869 header_length = sizeof(*header) + s->unknown_header_fields_size; 1870 total_size = bs->total_sectors * BDRV_SECTOR_SIZE; 1871 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3); 1872 1873 *header = (QCowHeader) { 1874 /* Version 2 fields */ 1875 .magic = cpu_to_be32(QCOW_MAGIC), 1876 .version = cpu_to_be32(s->qcow_version), 1877 .backing_file_offset = 0, 1878 .backing_file_size = 0, 1879 .cluster_bits = cpu_to_be32(s->cluster_bits), 1880 .size = cpu_to_be64(total_size), 1881 .crypt_method = cpu_to_be32(s->crypt_method_header), 1882 .l1_size = cpu_to_be32(s->l1_size), 1883 .l1_table_offset = cpu_to_be64(s->l1_table_offset), 1884 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset), 1885 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters), 1886 .nb_snapshots = cpu_to_be32(s->nb_snapshots), 1887 .snapshots_offset = cpu_to_be64(s->snapshots_offset), 1888 1889 /* Version 3 fields */ 1890 .incompatible_features = cpu_to_be64(s->incompatible_features), 1891 .compatible_features = cpu_to_be64(s->compatible_features), 1892 .autoclear_features = cpu_to_be64(s->autoclear_features), 1893 .refcount_order = cpu_to_be32(s->refcount_order), 1894 .header_length = cpu_to_be32(header_length), 1895 }; 1896 1897 /* For older versions, write a shorter header */ 1898 switch (s->qcow_version) { 1899 case 2: 1900 ret = offsetof(QCowHeader, incompatible_features); 1901 break; 1902 case 3: 1903 ret = sizeof(*header); 1904 break; 1905 default: 1906 ret = -EINVAL; 1907 goto fail; 1908 } 1909 1910 buf += ret; 1911 buflen -= ret; 1912 memset(buf, 0, buflen); 1913 1914 /* Preserve any unknown field in the header */ 1915 if (s->unknown_header_fields_size) { 1916 if (buflen < s->unknown_header_fields_size) { 1917 ret = -ENOSPC; 1918 goto fail; 1919 } 1920 1921 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size); 1922 buf += s->unknown_header_fields_size; 1923 buflen -= s->unknown_header_fields_size; 1924 } 1925 1926 /* Backing file format header extension */ 1927 if (s->image_backing_format) { 1928 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT, 1929 s->image_backing_format, 1930 strlen(s->image_backing_format), 1931 buflen); 1932 if (ret < 0) { 1933 goto fail; 1934 } 1935 1936 buf += ret; 1937 buflen -= ret; 1938 } 1939 1940 /* Feature table */ 1941 if (s->qcow_version >= 3) { 1942 Qcow2Feature features[] = { 1943 { 1944 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1945 .bit = QCOW2_INCOMPAT_DIRTY_BITNR, 1946 .name = "dirty bit", 1947 }, 1948 { 1949 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE, 1950 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR, 1951 .name = "corrupt bit", 1952 }, 1953 { 1954 .type = QCOW2_FEAT_TYPE_COMPATIBLE, 1955 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 1956 .name = "lazy refcounts", 1957 }, 1958 }; 1959 1960 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE, 1961 features, sizeof(features), buflen); 1962 if (ret < 0) { 1963 goto fail; 1964 } 1965 buf += ret; 1966 buflen -= ret; 1967 } 1968 1969 /* Keep unknown header extensions */ 1970 QLIST_FOREACH(uext, &s->unknown_header_ext, next) { 1971 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen); 1972 if (ret < 0) { 1973 goto fail; 1974 } 1975 1976 buf += ret; 1977 buflen -= ret; 1978 } 1979 1980 /* End of header extensions */ 1981 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen); 1982 if (ret < 0) { 1983 goto fail; 1984 } 1985 1986 buf += ret; 1987 buflen -= ret; 1988 1989 /* Backing file name */ 1990 if (s->image_backing_file) { 1991 size_t backing_file_len = strlen(s->image_backing_file); 1992 1993 if (buflen < backing_file_len) { 1994 ret = -ENOSPC; 1995 goto fail; 1996 } 1997 1998 /* Using strncpy is ok here, since buf is not NUL-terminated. */ 1999 strncpy(buf, s->image_backing_file, buflen); 2000 2001 header->backing_file_offset = cpu_to_be64(buf - ((char*) header)); 2002 header->backing_file_size = cpu_to_be32(backing_file_len); 2003 } 2004 2005 /* Write the new header */ 2006 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size); 2007 if (ret < 0) { 2008 goto fail; 2009 } 2010 2011 ret = 0; 2012 fail: 2013 qemu_vfree(header); 2014 return ret; 2015 } 2016 2017 static int qcow2_change_backing_file(BlockDriverState *bs, 2018 const char *backing_file, const char *backing_fmt) 2019 { 2020 BDRVQcow2State *s = bs->opaque; 2021 2022 if (backing_file && strlen(backing_file) > 1023) { 2023 return -EINVAL; 2024 } 2025 2026 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: ""); 2027 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: ""); 2028 2029 g_free(s->image_backing_file); 2030 g_free(s->image_backing_format); 2031 2032 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL; 2033 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL; 2034 2035 return qcow2_update_header(bs); 2036 } 2037 2038 static int preallocate(BlockDriverState *bs) 2039 { 2040 uint64_t bytes; 2041 uint64_t offset; 2042 uint64_t host_offset = 0; 2043 unsigned int cur_bytes; 2044 int ret; 2045 QCowL2Meta *meta; 2046 2047 bytes = bdrv_getlength(bs); 2048 offset = 0; 2049 2050 while (bytes) { 2051 cur_bytes = MIN(bytes, INT_MAX); 2052 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes, 2053 &host_offset, &meta); 2054 if (ret < 0) { 2055 return ret; 2056 } 2057 2058 while (meta) { 2059 QCowL2Meta *next = meta->next; 2060 2061 ret = qcow2_alloc_cluster_link_l2(bs, meta); 2062 if (ret < 0) { 2063 qcow2_free_any_clusters(bs, meta->alloc_offset, 2064 meta->nb_clusters, QCOW2_DISCARD_NEVER); 2065 return ret; 2066 } 2067 2068 /* There are no dependent requests, but we need to remove our 2069 * request from the list of in-flight requests */ 2070 QLIST_REMOVE(meta, next_in_flight); 2071 2072 g_free(meta); 2073 meta = next; 2074 } 2075 2076 /* TODO Preallocate data if requested */ 2077 2078 bytes -= cur_bytes; 2079 offset += cur_bytes; 2080 } 2081 2082 /* 2083 * It is expected that the image file is large enough to actually contain 2084 * all of the allocated clusters (otherwise we get failing reads after 2085 * EOF). Extend the image to the last allocated sector. 2086 */ 2087 if (host_offset != 0) { 2088 uint8_t data = 0; 2089 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1, 2090 &data, 1); 2091 if (ret < 0) { 2092 return ret; 2093 } 2094 } 2095 2096 return 0; 2097 } 2098 2099 static int qcow2_create2(const char *filename, int64_t total_size, 2100 const char *backing_file, const char *backing_format, 2101 int flags, size_t cluster_size, PreallocMode prealloc, 2102 QemuOpts *opts, int version, int refcount_order, 2103 Error **errp) 2104 { 2105 int cluster_bits; 2106 QDict *options; 2107 2108 /* Calculate cluster_bits */ 2109 cluster_bits = ctz32(cluster_size); 2110 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS || 2111 (1 << cluster_bits) != cluster_size) 2112 { 2113 error_setg(errp, "Cluster size must be a power of two between %d and " 2114 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10)); 2115 return -EINVAL; 2116 } 2117 2118 /* 2119 * Open the image file and write a minimal qcow2 header. 2120 * 2121 * We keep things simple and start with a zero-sized image. We also 2122 * do without refcount blocks or a L1 table for now. We'll fix the 2123 * inconsistency later. 2124 * 2125 * We do need a refcount table because growing the refcount table means 2126 * allocating two new refcount blocks - the seconds of which would be at 2127 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file 2128 * size for any qcow2 image. 2129 */ 2130 BlockBackend *blk; 2131 QCowHeader *header; 2132 uint64_t* refcount_table; 2133 Error *local_err = NULL; 2134 int ret; 2135 2136 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) { 2137 /* Note: The following calculation does not need to be exact; if it is a 2138 * bit off, either some bytes will be "leaked" (which is fine) or we 2139 * will need to increase the file size by some bytes (which is fine, 2140 * too, as long as the bulk is allocated here). Therefore, using 2141 * floating point arithmetic is fine. */ 2142 int64_t meta_size = 0; 2143 uint64_t nreftablee, nrefblocke, nl1e, nl2e, refblock_count; 2144 int64_t aligned_total_size = align_offset(total_size, cluster_size); 2145 int refblock_bits, refblock_size; 2146 /* refcount entry size in bytes */ 2147 double rces = (1 << refcount_order) / 8.; 2148 2149 /* see qcow2_open() */ 2150 refblock_bits = cluster_bits - (refcount_order - 3); 2151 refblock_size = 1 << refblock_bits; 2152 2153 /* header: 1 cluster */ 2154 meta_size += cluster_size; 2155 2156 /* total size of L2 tables */ 2157 nl2e = aligned_total_size / cluster_size; 2158 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t)); 2159 meta_size += nl2e * sizeof(uint64_t); 2160 2161 /* total size of L1 tables */ 2162 nl1e = nl2e * sizeof(uint64_t) / cluster_size; 2163 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t)); 2164 meta_size += nl1e * sizeof(uint64_t); 2165 2166 /* total size of refcount blocks 2167 * 2168 * note: every host cluster is reference-counted, including metadata 2169 * (even refcount blocks are recursively included). 2170 * Let: 2171 * a = total_size (this is the guest disk size) 2172 * m = meta size not including refcount blocks and refcount tables 2173 * c = cluster size 2174 * y1 = number of refcount blocks entries 2175 * y2 = meta size including everything 2176 * rces = refcount entry size in bytes 2177 * then, 2178 * y1 = (y2 + a)/c 2179 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m 2180 * we can get y1: 2181 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c) 2182 */ 2183 nrefblocke = (aligned_total_size + meta_size + cluster_size) 2184 / (cluster_size - rces - rces * sizeof(uint64_t) 2185 / cluster_size); 2186 refblock_count = DIV_ROUND_UP(nrefblocke, refblock_size); 2187 meta_size += refblock_count * cluster_size; 2188 2189 /* total size of refcount tables */ 2190 nreftablee = align_offset(refblock_count, 2191 cluster_size / sizeof(uint64_t)); 2192 meta_size += nreftablee * sizeof(uint64_t); 2193 2194 qemu_opt_set_number(opts, BLOCK_OPT_SIZE, 2195 aligned_total_size + meta_size, &error_abort); 2196 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc], 2197 &error_abort); 2198 } 2199 2200 ret = bdrv_create_file(filename, opts, &local_err); 2201 if (ret < 0) { 2202 error_propagate(errp, local_err); 2203 return ret; 2204 } 2205 2206 blk = blk_new_open(filename, NULL, NULL, 2207 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, 2208 &local_err); 2209 if (blk == NULL) { 2210 error_propagate(errp, local_err); 2211 return -EIO; 2212 } 2213 2214 blk_set_allow_write_beyond_eof(blk, true); 2215 2216 /* Write the header */ 2217 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header)); 2218 header = g_malloc0(cluster_size); 2219 *header = (QCowHeader) { 2220 .magic = cpu_to_be32(QCOW_MAGIC), 2221 .version = cpu_to_be32(version), 2222 .cluster_bits = cpu_to_be32(cluster_bits), 2223 .size = cpu_to_be64(0), 2224 .l1_table_offset = cpu_to_be64(0), 2225 .l1_size = cpu_to_be32(0), 2226 .refcount_table_offset = cpu_to_be64(cluster_size), 2227 .refcount_table_clusters = cpu_to_be32(1), 2228 .refcount_order = cpu_to_be32(refcount_order), 2229 .header_length = cpu_to_be32(sizeof(*header)), 2230 }; 2231 2232 if (flags & BLOCK_FLAG_ENCRYPT) { 2233 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 2234 } else { 2235 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 2236 } 2237 2238 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) { 2239 header->compatible_features |= 2240 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS); 2241 } 2242 2243 ret = blk_pwrite(blk, 0, header, cluster_size, 0); 2244 g_free(header); 2245 if (ret < 0) { 2246 error_setg_errno(errp, -ret, "Could not write qcow2 header"); 2247 goto out; 2248 } 2249 2250 /* Write a refcount table with one refcount block */ 2251 refcount_table = g_malloc0(2 * cluster_size); 2252 refcount_table[0] = cpu_to_be64(2 * cluster_size); 2253 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0); 2254 g_free(refcount_table); 2255 2256 if (ret < 0) { 2257 error_setg_errno(errp, -ret, "Could not write refcount table"); 2258 goto out; 2259 } 2260 2261 blk_unref(blk); 2262 blk = NULL; 2263 2264 /* 2265 * And now open the image and make it consistent first (i.e. increase the 2266 * refcount of the cluster that is occupied by the header and the refcount 2267 * table) 2268 */ 2269 options = qdict_new(); 2270 qdict_put_str(options, "driver", "qcow2"); 2271 blk = blk_new_open(filename, NULL, options, 2272 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_NO_FLUSH, 2273 &local_err); 2274 if (blk == NULL) { 2275 error_propagate(errp, local_err); 2276 ret = -EIO; 2277 goto out; 2278 } 2279 2280 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size); 2281 if (ret < 0) { 2282 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 " 2283 "header and refcount table"); 2284 goto out; 2285 2286 } else if (ret != 0) { 2287 error_report("Huh, first cluster in empty image is already in use?"); 2288 abort(); 2289 } 2290 2291 /* Create a full header (including things like feature table) */ 2292 ret = qcow2_update_header(blk_bs(blk)); 2293 if (ret < 0) { 2294 error_setg_errno(errp, -ret, "Could not update qcow2 header"); 2295 goto out; 2296 } 2297 2298 /* Okay, now that we have a valid image, let's give it the right size */ 2299 ret = blk_truncate(blk, total_size, errp); 2300 if (ret < 0) { 2301 error_prepend(errp, "Could not resize image: "); 2302 goto out; 2303 } 2304 2305 /* Want a backing file? There you go.*/ 2306 if (backing_file) { 2307 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format); 2308 if (ret < 0) { 2309 error_setg_errno(errp, -ret, "Could not assign backing file '%s' " 2310 "with format '%s'", backing_file, backing_format); 2311 goto out; 2312 } 2313 } 2314 2315 /* And if we're supposed to preallocate metadata, do that now */ 2316 if (prealloc != PREALLOC_MODE_OFF) { 2317 BDRVQcow2State *s = blk_bs(blk)->opaque; 2318 qemu_co_mutex_lock(&s->lock); 2319 ret = preallocate(blk_bs(blk)); 2320 qemu_co_mutex_unlock(&s->lock); 2321 if (ret < 0) { 2322 error_setg_errno(errp, -ret, "Could not preallocate metadata"); 2323 goto out; 2324 } 2325 } 2326 2327 blk_unref(blk); 2328 blk = NULL; 2329 2330 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ 2331 options = qdict_new(); 2332 qdict_put_str(options, "driver", "qcow2"); 2333 blk = blk_new_open(filename, NULL, options, 2334 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err); 2335 if (blk == NULL) { 2336 error_propagate(errp, local_err); 2337 ret = -EIO; 2338 goto out; 2339 } 2340 2341 ret = 0; 2342 out: 2343 if (blk) { 2344 blk_unref(blk); 2345 } 2346 return ret; 2347 } 2348 2349 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp) 2350 { 2351 char *backing_file = NULL; 2352 char *backing_fmt = NULL; 2353 char *buf = NULL; 2354 uint64_t size = 0; 2355 int flags = 0; 2356 size_t cluster_size = DEFAULT_CLUSTER_SIZE; 2357 PreallocMode prealloc; 2358 int version = 3; 2359 uint64_t refcount_bits = 16; 2360 int refcount_order; 2361 Error *local_err = NULL; 2362 int ret; 2363 2364 /* Read out options */ 2365 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 2366 BDRV_SECTOR_SIZE); 2367 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 2368 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 2369 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 2370 flags |= BLOCK_FLAG_ENCRYPT; 2371 } 2372 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE, 2373 DEFAULT_CLUSTER_SIZE); 2374 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 2375 prealloc = qapi_enum_parse(PreallocMode_lookup, buf, 2376 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF, 2377 &local_err); 2378 if (local_err) { 2379 error_propagate(errp, local_err); 2380 ret = -EINVAL; 2381 goto finish; 2382 } 2383 g_free(buf); 2384 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL); 2385 if (!buf) { 2386 /* keep the default */ 2387 } else if (!strcmp(buf, "0.10")) { 2388 version = 2; 2389 } else if (!strcmp(buf, "1.1")) { 2390 version = 3; 2391 } else { 2392 error_setg(errp, "Invalid compatibility level: '%s'", buf); 2393 ret = -EINVAL; 2394 goto finish; 2395 } 2396 2397 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) { 2398 flags |= BLOCK_FLAG_LAZY_REFCOUNTS; 2399 } 2400 2401 if (backing_file && prealloc != PREALLOC_MODE_OFF) { 2402 error_setg(errp, "Backing file and preallocation cannot be used at " 2403 "the same time"); 2404 ret = -EINVAL; 2405 goto finish; 2406 } 2407 2408 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) { 2409 error_setg(errp, "Lazy refcounts only supported with compatibility " 2410 "level 1.1 and above (use compat=1.1 or greater)"); 2411 ret = -EINVAL; 2412 goto finish; 2413 } 2414 2415 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS, 2416 refcount_bits); 2417 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) { 2418 error_setg(errp, "Refcount width must be a power of two and may not " 2419 "exceed 64 bits"); 2420 ret = -EINVAL; 2421 goto finish; 2422 } 2423 2424 if (version < 3 && refcount_bits != 16) { 2425 error_setg(errp, "Different refcount widths than 16 bits require " 2426 "compatibility level 1.1 or above (use compat=1.1 or " 2427 "greater)"); 2428 ret = -EINVAL; 2429 goto finish; 2430 } 2431 2432 refcount_order = ctz32(refcount_bits); 2433 2434 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags, 2435 cluster_size, prealloc, opts, version, refcount_order, 2436 &local_err); 2437 error_propagate(errp, local_err); 2438 2439 finish: 2440 g_free(backing_file); 2441 g_free(backing_fmt); 2442 g_free(buf); 2443 return ret; 2444 } 2445 2446 2447 static bool is_zero_sectors(BlockDriverState *bs, int64_t start, 2448 uint32_t count) 2449 { 2450 int nr; 2451 BlockDriverState *file; 2452 int64_t res; 2453 2454 if (start + count > bs->total_sectors) { 2455 count = bs->total_sectors - start; 2456 } 2457 2458 if (!count) { 2459 return true; 2460 } 2461 res = bdrv_get_block_status_above(bs, NULL, start, count, 2462 &nr, &file); 2463 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count; 2464 } 2465 2466 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs, 2467 int64_t offset, int count, BdrvRequestFlags flags) 2468 { 2469 int ret; 2470 BDRVQcow2State *s = bs->opaque; 2471 2472 uint32_t head = offset % s->cluster_size; 2473 uint32_t tail = (offset + count) % s->cluster_size; 2474 2475 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, count); 2476 if (offset + count == bs->total_sectors * BDRV_SECTOR_SIZE) { 2477 tail = 0; 2478 } 2479 2480 if (head || tail) { 2481 int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS; 2482 uint64_t off; 2483 unsigned int nr; 2484 2485 assert(head + count <= s->cluster_size); 2486 2487 /* check whether remainder of cluster already reads as zero */ 2488 if (!(is_zero_sectors(bs, cl_start, 2489 DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) && 2490 is_zero_sectors(bs, (offset + count) >> BDRV_SECTOR_BITS, 2491 DIV_ROUND_UP(-tail & (s->cluster_size - 1), 2492 BDRV_SECTOR_SIZE)))) { 2493 return -ENOTSUP; 2494 } 2495 2496 qemu_co_mutex_lock(&s->lock); 2497 /* We can have new write after previous check */ 2498 offset = cl_start << BDRV_SECTOR_BITS; 2499 count = s->cluster_size; 2500 nr = s->cluster_size; 2501 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off); 2502 if (ret != QCOW2_CLUSTER_UNALLOCATED && 2503 ret != QCOW2_CLUSTER_ZERO_PLAIN && 2504 ret != QCOW2_CLUSTER_ZERO_ALLOC) { 2505 qemu_co_mutex_unlock(&s->lock); 2506 return -ENOTSUP; 2507 } 2508 } else { 2509 qemu_co_mutex_lock(&s->lock); 2510 } 2511 2512 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, count); 2513 2514 /* Whatever is left can use real zero clusters */ 2515 ret = qcow2_cluster_zeroize(bs, offset, count, flags); 2516 qemu_co_mutex_unlock(&s->lock); 2517 2518 return ret; 2519 } 2520 2521 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs, 2522 int64_t offset, int count) 2523 { 2524 int ret; 2525 BDRVQcow2State *s = bs->opaque; 2526 2527 if (!QEMU_IS_ALIGNED(offset | count, s->cluster_size)) { 2528 assert(count < s->cluster_size); 2529 /* Ignore partial clusters, except for the special case of the 2530 * complete partial cluster at the end of an unaligned file */ 2531 if (!QEMU_IS_ALIGNED(offset, s->cluster_size) || 2532 offset + count != bs->total_sectors * BDRV_SECTOR_SIZE) { 2533 return -ENOTSUP; 2534 } 2535 } 2536 2537 qemu_co_mutex_lock(&s->lock); 2538 ret = qcow2_cluster_discard(bs, offset, count, QCOW2_DISCARD_REQUEST, 2539 false); 2540 qemu_co_mutex_unlock(&s->lock); 2541 return ret; 2542 } 2543 2544 static int qcow2_truncate(BlockDriverState *bs, int64_t offset, Error **errp) 2545 { 2546 BDRVQcow2State *s = bs->opaque; 2547 int64_t new_l1_size; 2548 int ret; 2549 2550 if (offset & 511) { 2551 error_setg(errp, "The new size must be a multiple of 512"); 2552 return -EINVAL; 2553 } 2554 2555 /* cannot proceed if image has snapshots */ 2556 if (s->nb_snapshots) { 2557 error_setg(errp, "Can't resize an image which has snapshots"); 2558 return -ENOTSUP; 2559 } 2560 2561 /* shrinking is currently not supported */ 2562 if (offset < bs->total_sectors * 512) { 2563 error_setg(errp, "qcow2 doesn't support shrinking images yet"); 2564 return -ENOTSUP; 2565 } 2566 2567 new_l1_size = size_to_l1(s, offset); 2568 ret = qcow2_grow_l1_table(bs, new_l1_size, true); 2569 if (ret < 0) { 2570 error_setg_errno(errp, -ret, "Failed to grow the L1 table"); 2571 return ret; 2572 } 2573 2574 /* write updated header.size */ 2575 offset = cpu_to_be64(offset); 2576 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size), 2577 &offset, sizeof(uint64_t)); 2578 if (ret < 0) { 2579 error_setg_errno(errp, -ret, "Failed to update the image size"); 2580 return ret; 2581 } 2582 2583 s->l1_vm_state_index = new_l1_size; 2584 return 0; 2585 } 2586 2587 /* XXX: put compressed sectors first, then all the cluster aligned 2588 tables to avoid losing bytes in alignment */ 2589 static coroutine_fn int 2590 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 2591 uint64_t bytes, QEMUIOVector *qiov) 2592 { 2593 BDRVQcow2State *s = bs->opaque; 2594 QEMUIOVector hd_qiov; 2595 struct iovec iov; 2596 z_stream strm; 2597 int ret, out_len; 2598 uint8_t *buf, *out_buf; 2599 uint64_t cluster_offset; 2600 2601 if (bytes == 0) { 2602 /* align end of file to a sector boundary to ease reading with 2603 sector based I/Os */ 2604 cluster_offset = bdrv_getlength(bs->file->bs); 2605 return bdrv_truncate(bs->file, cluster_offset, NULL); 2606 } 2607 2608 buf = qemu_blockalign(bs, s->cluster_size); 2609 if (bytes != s->cluster_size) { 2610 if (bytes > s->cluster_size || 2611 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 2612 { 2613 qemu_vfree(buf); 2614 return -EINVAL; 2615 } 2616 /* Zero-pad last write if image size is not cluster aligned */ 2617 memset(buf + bytes, 0, s->cluster_size - bytes); 2618 } 2619 qemu_iovec_to_buf(qiov, 0, buf, bytes); 2620 2621 out_buf = g_malloc(s->cluster_size); 2622 2623 /* best compression, small window, no zlib header */ 2624 memset(&strm, 0, sizeof(strm)); 2625 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 2626 Z_DEFLATED, -12, 2627 9, Z_DEFAULT_STRATEGY); 2628 if (ret != 0) { 2629 ret = -EINVAL; 2630 goto fail; 2631 } 2632 2633 strm.avail_in = s->cluster_size; 2634 strm.next_in = (uint8_t *)buf; 2635 strm.avail_out = s->cluster_size; 2636 strm.next_out = out_buf; 2637 2638 ret = deflate(&strm, Z_FINISH); 2639 if (ret != Z_STREAM_END && ret != Z_OK) { 2640 deflateEnd(&strm); 2641 ret = -EINVAL; 2642 goto fail; 2643 } 2644 out_len = strm.next_out - out_buf; 2645 2646 deflateEnd(&strm); 2647 2648 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 2649 /* could not compress: write normal cluster */ 2650 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0); 2651 if (ret < 0) { 2652 goto fail; 2653 } 2654 goto success; 2655 } 2656 2657 qemu_co_mutex_lock(&s->lock); 2658 cluster_offset = 2659 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len); 2660 if (!cluster_offset) { 2661 qemu_co_mutex_unlock(&s->lock); 2662 ret = -EIO; 2663 goto fail; 2664 } 2665 cluster_offset &= s->cluster_offset_mask; 2666 2667 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len); 2668 qemu_co_mutex_unlock(&s->lock); 2669 if (ret < 0) { 2670 goto fail; 2671 } 2672 2673 iov = (struct iovec) { 2674 .iov_base = out_buf, 2675 .iov_len = out_len, 2676 }; 2677 qemu_iovec_init_external(&hd_qiov, &iov, 1); 2678 2679 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 2680 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 2681 if (ret < 0) { 2682 goto fail; 2683 } 2684 success: 2685 ret = 0; 2686 fail: 2687 qemu_vfree(buf); 2688 g_free(out_buf); 2689 return ret; 2690 } 2691 2692 static int make_completely_empty(BlockDriverState *bs) 2693 { 2694 BDRVQcow2State *s = bs->opaque; 2695 Error *local_err = NULL; 2696 int ret, l1_clusters; 2697 int64_t offset; 2698 uint64_t *new_reftable = NULL; 2699 uint64_t rt_entry, l1_size2; 2700 struct { 2701 uint64_t l1_offset; 2702 uint64_t reftable_offset; 2703 uint32_t reftable_clusters; 2704 } QEMU_PACKED l1_ofs_rt_ofs_cls; 2705 2706 ret = qcow2_cache_empty(bs, s->l2_table_cache); 2707 if (ret < 0) { 2708 goto fail; 2709 } 2710 2711 ret = qcow2_cache_empty(bs, s->refcount_block_cache); 2712 if (ret < 0) { 2713 goto fail; 2714 } 2715 2716 /* Refcounts will be broken utterly */ 2717 ret = qcow2_mark_dirty(bs); 2718 if (ret < 0) { 2719 goto fail; 2720 } 2721 2722 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2723 2724 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2725 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t); 2726 2727 /* After this call, neither the in-memory nor the on-disk refcount 2728 * information accurately describe the actual references */ 2729 2730 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset, 2731 l1_clusters * s->cluster_size, 0); 2732 if (ret < 0) { 2733 goto fail_broken_refcounts; 2734 } 2735 memset(s->l1_table, 0, l1_size2); 2736 2737 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE); 2738 2739 /* Overwrite enough clusters at the beginning of the sectors to place 2740 * the refcount table, a refcount block and the L1 table in; this may 2741 * overwrite parts of the existing refcount and L1 table, which is not 2742 * an issue because the dirty flag is set, complete data loss is in fact 2743 * desired and partial data loss is consequently fine as well */ 2744 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size, 2745 (2 + l1_clusters) * s->cluster_size, 0); 2746 /* This call (even if it failed overall) may have overwritten on-disk 2747 * refcount structures; in that case, the in-memory refcount information 2748 * will probably differ from the on-disk information which makes the BDS 2749 * unusable */ 2750 if (ret < 0) { 2751 goto fail_broken_refcounts; 2752 } 2753 2754 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 2755 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE); 2756 2757 /* "Create" an empty reftable (one cluster) directly after the image 2758 * header and an empty L1 table three clusters after the image header; 2759 * the cluster between those two will be used as the first refblock */ 2760 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size); 2761 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size); 2762 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1); 2763 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset), 2764 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls)); 2765 if (ret < 0) { 2766 goto fail_broken_refcounts; 2767 } 2768 2769 s->l1_table_offset = 3 * s->cluster_size; 2770 2771 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t)); 2772 if (!new_reftable) { 2773 ret = -ENOMEM; 2774 goto fail_broken_refcounts; 2775 } 2776 2777 s->refcount_table_offset = s->cluster_size; 2778 s->refcount_table_size = s->cluster_size / sizeof(uint64_t); 2779 s->max_refcount_table_index = 0; 2780 2781 g_free(s->refcount_table); 2782 s->refcount_table = new_reftable; 2783 new_reftable = NULL; 2784 2785 /* Now the in-memory refcount information again corresponds to the on-disk 2786 * information (reftable is empty and no refblocks (the refblock cache is 2787 * empty)); however, this means some clusters (e.g. the image header) are 2788 * referenced, but not refcounted, but the normal qcow2 code assumes that 2789 * the in-memory information is always correct */ 2790 2791 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC); 2792 2793 /* Enter the first refblock into the reftable */ 2794 rt_entry = cpu_to_be64(2 * s->cluster_size); 2795 ret = bdrv_pwrite_sync(bs->file, s->cluster_size, 2796 &rt_entry, sizeof(rt_entry)); 2797 if (ret < 0) { 2798 goto fail_broken_refcounts; 2799 } 2800 s->refcount_table[0] = 2 * s->cluster_size; 2801 2802 s->free_cluster_index = 0; 2803 assert(3 + l1_clusters <= s->refcount_block_size); 2804 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2); 2805 if (offset < 0) { 2806 ret = offset; 2807 goto fail_broken_refcounts; 2808 } else if (offset > 0) { 2809 error_report("First cluster in emptied image is in use"); 2810 abort(); 2811 } 2812 2813 /* Now finally the in-memory information corresponds to the on-disk 2814 * structures and is correct */ 2815 ret = qcow2_mark_clean(bs); 2816 if (ret < 0) { 2817 goto fail; 2818 } 2819 2820 ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size, 2821 &local_err); 2822 if (ret < 0) { 2823 error_report_err(local_err); 2824 goto fail; 2825 } 2826 2827 return 0; 2828 2829 fail_broken_refcounts: 2830 /* The BDS is unusable at this point. If we wanted to make it usable, we 2831 * would have to call qcow2_refcount_close(), qcow2_refcount_init(), 2832 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init() 2833 * again. However, because the functions which could have caused this error 2834 * path to be taken are used by those functions as well, it's very likely 2835 * that that sequence will fail as well. Therefore, just eject the BDS. */ 2836 bs->drv = NULL; 2837 2838 fail: 2839 g_free(new_reftable); 2840 return ret; 2841 } 2842 2843 static int qcow2_make_empty(BlockDriverState *bs) 2844 { 2845 BDRVQcow2State *s = bs->opaque; 2846 uint64_t offset, end_offset; 2847 int step = QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size); 2848 int l1_clusters, ret = 0; 2849 2850 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t)); 2851 2852 if (s->qcow_version >= 3 && !s->snapshots && 2853 3 + l1_clusters <= s->refcount_block_size) { 2854 /* The following function only works for qcow2 v3 images (it requires 2855 * the dirty flag) and only as long as there are no snapshots (because 2856 * it completely empties the image). Furthermore, the L1 table and three 2857 * additional clusters (image header, refcount table, one refcount 2858 * block) have to fit inside one refcount block. */ 2859 return make_completely_empty(bs); 2860 } 2861 2862 /* This fallback code simply discards every active cluster; this is slow, 2863 * but works in all cases */ 2864 end_offset = bs->total_sectors * BDRV_SECTOR_SIZE; 2865 for (offset = 0; offset < end_offset; offset += step) { 2866 /* As this function is generally used after committing an external 2867 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the 2868 * default action for this kind of discard is to pass the discard, 2869 * which will ideally result in an actually smaller image file, as 2870 * is probably desired. */ 2871 ret = qcow2_cluster_discard(bs, offset, MIN(step, end_offset - offset), 2872 QCOW2_DISCARD_SNAPSHOT, true); 2873 if (ret < 0) { 2874 break; 2875 } 2876 } 2877 2878 return ret; 2879 } 2880 2881 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) 2882 { 2883 BDRVQcow2State *s = bs->opaque; 2884 int ret; 2885 2886 qemu_co_mutex_lock(&s->lock); 2887 ret = qcow2_cache_write(bs, s->l2_table_cache); 2888 if (ret < 0) { 2889 qemu_co_mutex_unlock(&s->lock); 2890 return ret; 2891 } 2892 2893 if (qcow2_need_accurate_refcounts(s)) { 2894 ret = qcow2_cache_write(bs, s->refcount_block_cache); 2895 if (ret < 0) { 2896 qemu_co_mutex_unlock(&s->lock); 2897 return ret; 2898 } 2899 } 2900 qemu_co_mutex_unlock(&s->lock); 2901 2902 return 0; 2903 } 2904 2905 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 2906 { 2907 BDRVQcow2State *s = bs->opaque; 2908 bdi->unallocated_blocks_are_zero = true; 2909 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3); 2910 bdi->cluster_size = s->cluster_size; 2911 bdi->vm_state_offset = qcow2_vm_state_offset(s); 2912 return 0; 2913 } 2914 2915 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs) 2916 { 2917 BDRVQcow2State *s = bs->opaque; 2918 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1); 2919 2920 *spec_info = (ImageInfoSpecific){ 2921 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2, 2922 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1), 2923 }; 2924 if (s->qcow_version == 2) { 2925 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2926 .compat = g_strdup("0.10"), 2927 .refcount_bits = s->refcount_bits, 2928 }; 2929 } else if (s->qcow_version == 3) { 2930 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){ 2931 .compat = g_strdup("1.1"), 2932 .lazy_refcounts = s->compatible_features & 2933 QCOW2_COMPAT_LAZY_REFCOUNTS, 2934 .has_lazy_refcounts = true, 2935 .corrupt = s->incompatible_features & 2936 QCOW2_INCOMPAT_CORRUPT, 2937 .has_corrupt = true, 2938 .refcount_bits = s->refcount_bits, 2939 }; 2940 } else { 2941 /* if this assertion fails, this probably means a new version was 2942 * added without having it covered here */ 2943 assert(false); 2944 } 2945 2946 return spec_info; 2947 } 2948 2949 #if 0 2950 static void dump_refcounts(BlockDriverState *bs) 2951 { 2952 BDRVQcow2State *s = bs->opaque; 2953 int64_t nb_clusters, k, k1, size; 2954 int refcount; 2955 2956 size = bdrv_getlength(bs->file->bs); 2957 nb_clusters = size_to_clusters(s, size); 2958 for(k = 0; k < nb_clusters;) { 2959 k1 = k; 2960 refcount = get_refcount(bs, k); 2961 k++; 2962 while (k < nb_clusters && get_refcount(bs, k) == refcount) 2963 k++; 2964 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount, 2965 k - k1); 2966 } 2967 } 2968 #endif 2969 2970 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2971 int64_t pos) 2972 { 2973 BDRVQcow2State *s = bs->opaque; 2974 2975 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE); 2976 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos, 2977 qiov->size, qiov, 0); 2978 } 2979 2980 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, 2981 int64_t pos) 2982 { 2983 BDRVQcow2State *s = bs->opaque; 2984 2985 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD); 2986 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos, 2987 qiov->size, qiov, 0); 2988 } 2989 2990 /* 2991 * Downgrades an image's version. To achieve this, any incompatible features 2992 * have to be removed. 2993 */ 2994 static int qcow2_downgrade(BlockDriverState *bs, int target_version, 2995 BlockDriverAmendStatusCB *status_cb, void *cb_opaque) 2996 { 2997 BDRVQcow2State *s = bs->opaque; 2998 int current_version = s->qcow_version; 2999 int ret; 3000 3001 if (target_version == current_version) { 3002 return 0; 3003 } else if (target_version > current_version) { 3004 return -EINVAL; 3005 } else if (target_version != 2) { 3006 return -EINVAL; 3007 } 3008 3009 if (s->refcount_order != 4) { 3010 error_report("compat=0.10 requires refcount_bits=16"); 3011 return -ENOTSUP; 3012 } 3013 3014 /* clear incompatible features */ 3015 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) { 3016 ret = qcow2_mark_clean(bs); 3017 if (ret < 0) { 3018 return ret; 3019 } 3020 } 3021 3022 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in 3023 * the first place; if that happens nonetheless, returning -ENOTSUP is the 3024 * best thing to do anyway */ 3025 3026 if (s->incompatible_features) { 3027 return -ENOTSUP; 3028 } 3029 3030 /* since we can ignore compatible features, we can set them to 0 as well */ 3031 s->compatible_features = 0; 3032 /* if lazy refcounts have been used, they have already been fixed through 3033 * clearing the dirty flag */ 3034 3035 /* clearing autoclear features is trivial */ 3036 s->autoclear_features = 0; 3037 3038 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque); 3039 if (ret < 0) { 3040 return ret; 3041 } 3042 3043 s->qcow_version = target_version; 3044 ret = qcow2_update_header(bs); 3045 if (ret < 0) { 3046 s->qcow_version = current_version; 3047 return ret; 3048 } 3049 return 0; 3050 } 3051 3052 typedef enum Qcow2AmendOperation { 3053 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be 3054 * statically initialized to so that the helper CB can discern the first 3055 * invocation from an operation change */ 3056 QCOW2_NO_OPERATION = 0, 3057 3058 QCOW2_CHANGING_REFCOUNT_ORDER, 3059 QCOW2_DOWNGRADING, 3060 } Qcow2AmendOperation; 3061 3062 typedef struct Qcow2AmendHelperCBInfo { 3063 /* The code coordinating the amend operations should only modify 3064 * these four fields; the rest will be managed by the CB */ 3065 BlockDriverAmendStatusCB *original_status_cb; 3066 void *original_cb_opaque; 3067 3068 Qcow2AmendOperation current_operation; 3069 3070 /* Total number of operations to perform (only set once) */ 3071 int total_operations; 3072 3073 /* The following fields are managed by the CB */ 3074 3075 /* Number of operations completed */ 3076 int operations_completed; 3077 3078 /* Cumulative offset of all completed operations */ 3079 int64_t offset_completed; 3080 3081 Qcow2AmendOperation last_operation; 3082 int64_t last_work_size; 3083 } Qcow2AmendHelperCBInfo; 3084 3085 static void qcow2_amend_helper_cb(BlockDriverState *bs, 3086 int64_t operation_offset, 3087 int64_t operation_work_size, void *opaque) 3088 { 3089 Qcow2AmendHelperCBInfo *info = opaque; 3090 int64_t current_work_size; 3091 int64_t projected_work_size; 3092 3093 if (info->current_operation != info->last_operation) { 3094 if (info->last_operation != QCOW2_NO_OPERATION) { 3095 info->offset_completed += info->last_work_size; 3096 info->operations_completed++; 3097 } 3098 3099 info->last_operation = info->current_operation; 3100 } 3101 3102 assert(info->total_operations > 0); 3103 assert(info->operations_completed < info->total_operations); 3104 3105 info->last_work_size = operation_work_size; 3106 3107 current_work_size = info->offset_completed + operation_work_size; 3108 3109 /* current_work_size is the total work size for (operations_completed + 1) 3110 * operations (which includes this one), so multiply it by the number of 3111 * operations not covered and divide it by the number of operations 3112 * covered to get a projection for the operations not covered */ 3113 projected_work_size = current_work_size * (info->total_operations - 3114 info->operations_completed - 1) 3115 / (info->operations_completed + 1); 3116 3117 info->original_status_cb(bs, info->offset_completed + operation_offset, 3118 current_work_size + projected_work_size, 3119 info->original_cb_opaque); 3120 } 3121 3122 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts, 3123 BlockDriverAmendStatusCB *status_cb, 3124 void *cb_opaque) 3125 { 3126 BDRVQcow2State *s = bs->opaque; 3127 int old_version = s->qcow_version, new_version = old_version; 3128 uint64_t new_size = 0; 3129 const char *backing_file = NULL, *backing_format = NULL; 3130 bool lazy_refcounts = s->use_lazy_refcounts; 3131 const char *compat = NULL; 3132 uint64_t cluster_size = s->cluster_size; 3133 bool encrypt; 3134 int refcount_bits = s->refcount_bits; 3135 Error *local_err = NULL; 3136 int ret; 3137 QemuOptDesc *desc = opts->list->desc; 3138 Qcow2AmendHelperCBInfo helper_cb_info; 3139 3140 while (desc && desc->name) { 3141 if (!qemu_opt_find(opts, desc->name)) { 3142 /* only change explicitly defined options */ 3143 desc++; 3144 continue; 3145 } 3146 3147 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) { 3148 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL); 3149 if (!compat) { 3150 /* preserve default */ 3151 } else if (!strcmp(compat, "0.10")) { 3152 new_version = 2; 3153 } else if (!strcmp(compat, "1.1")) { 3154 new_version = 3; 3155 } else { 3156 error_report("Unknown compatibility level %s", compat); 3157 return -EINVAL; 3158 } 3159 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) { 3160 error_report("Cannot change preallocation mode"); 3161 return -ENOTSUP; 3162 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) { 3163 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0); 3164 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) { 3165 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE); 3166 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) { 3167 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT); 3168 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) { 3169 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT, 3170 !!s->cipher); 3171 3172 if (encrypt != !!s->cipher) { 3173 error_report("Changing the encryption flag is not supported"); 3174 return -ENOTSUP; 3175 } 3176 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) { 3177 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE, 3178 cluster_size); 3179 if (cluster_size != s->cluster_size) { 3180 error_report("Changing the cluster size is not supported"); 3181 return -ENOTSUP; 3182 } 3183 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) { 3184 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS, 3185 lazy_refcounts); 3186 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) { 3187 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS, 3188 refcount_bits); 3189 3190 if (refcount_bits <= 0 || refcount_bits > 64 || 3191 !is_power_of_2(refcount_bits)) 3192 { 3193 error_report("Refcount width must be a power of two and may " 3194 "not exceed 64 bits"); 3195 return -EINVAL; 3196 } 3197 } else { 3198 /* if this point is reached, this probably means a new option was 3199 * added without having it covered here */ 3200 abort(); 3201 } 3202 3203 desc++; 3204 } 3205 3206 helper_cb_info = (Qcow2AmendHelperCBInfo){ 3207 .original_status_cb = status_cb, 3208 .original_cb_opaque = cb_opaque, 3209 .total_operations = (new_version < old_version) 3210 + (s->refcount_bits != refcount_bits) 3211 }; 3212 3213 /* Upgrade first (some features may require compat=1.1) */ 3214 if (new_version > old_version) { 3215 s->qcow_version = new_version; 3216 ret = qcow2_update_header(bs); 3217 if (ret < 0) { 3218 s->qcow_version = old_version; 3219 return ret; 3220 } 3221 } 3222 3223 if (s->refcount_bits != refcount_bits) { 3224 int refcount_order = ctz32(refcount_bits); 3225 3226 if (new_version < 3 && refcount_bits != 16) { 3227 error_report("Different refcount widths than 16 bits require " 3228 "compatibility level 1.1 or above (use compat=1.1 or " 3229 "greater)"); 3230 return -EINVAL; 3231 } 3232 3233 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER; 3234 ret = qcow2_change_refcount_order(bs, refcount_order, 3235 &qcow2_amend_helper_cb, 3236 &helper_cb_info, &local_err); 3237 if (ret < 0) { 3238 error_report_err(local_err); 3239 return ret; 3240 } 3241 } 3242 3243 if (backing_file || backing_format) { 3244 ret = qcow2_change_backing_file(bs, 3245 backing_file ?: s->image_backing_file, 3246 backing_format ?: s->image_backing_format); 3247 if (ret < 0) { 3248 return ret; 3249 } 3250 } 3251 3252 if (s->use_lazy_refcounts != lazy_refcounts) { 3253 if (lazy_refcounts) { 3254 if (new_version < 3) { 3255 error_report("Lazy refcounts only supported with compatibility " 3256 "level 1.1 and above (use compat=1.1 or greater)"); 3257 return -EINVAL; 3258 } 3259 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3260 ret = qcow2_update_header(bs); 3261 if (ret < 0) { 3262 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3263 return ret; 3264 } 3265 s->use_lazy_refcounts = true; 3266 } else { 3267 /* make image clean first */ 3268 ret = qcow2_mark_clean(bs); 3269 if (ret < 0) { 3270 return ret; 3271 } 3272 /* now disallow lazy refcounts */ 3273 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS; 3274 ret = qcow2_update_header(bs); 3275 if (ret < 0) { 3276 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS; 3277 return ret; 3278 } 3279 s->use_lazy_refcounts = false; 3280 } 3281 } 3282 3283 if (new_size) { 3284 BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL); 3285 ret = blk_insert_bs(blk, bs, &local_err); 3286 if (ret < 0) { 3287 error_report_err(local_err); 3288 blk_unref(blk); 3289 return ret; 3290 } 3291 3292 ret = blk_truncate(blk, new_size, &local_err); 3293 blk_unref(blk); 3294 if (ret < 0) { 3295 error_report_err(local_err); 3296 return ret; 3297 } 3298 } 3299 3300 /* Downgrade last (so unsupported features can be removed before) */ 3301 if (new_version < old_version) { 3302 helper_cb_info.current_operation = QCOW2_DOWNGRADING; 3303 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb, 3304 &helper_cb_info); 3305 if (ret < 0) { 3306 return ret; 3307 } 3308 } 3309 3310 return 0; 3311 } 3312 3313 /* 3314 * If offset or size are negative, respectively, they will not be included in 3315 * the BLOCK_IMAGE_CORRUPTED event emitted. 3316 * fatal will be ignored for read-only BDS; corruptions found there will always 3317 * be considered non-fatal. 3318 */ 3319 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 3320 int64_t size, const char *message_format, ...) 3321 { 3322 BDRVQcow2State *s = bs->opaque; 3323 const char *node_name; 3324 char *message; 3325 va_list ap; 3326 3327 fatal = fatal && !bs->read_only; 3328 3329 if (s->signaled_corruption && 3330 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT))) 3331 { 3332 return; 3333 } 3334 3335 va_start(ap, message_format); 3336 message = g_strdup_vprintf(message_format, ap); 3337 va_end(ap); 3338 3339 if (fatal) { 3340 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further " 3341 "corruption events will be suppressed\n", message); 3342 } else { 3343 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal " 3344 "corruption events will be suppressed\n", message); 3345 } 3346 3347 node_name = bdrv_get_node_name(bs); 3348 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs), 3349 *node_name != '\0', node_name, 3350 message, offset >= 0, offset, 3351 size >= 0, size, 3352 fatal, &error_abort); 3353 g_free(message); 3354 3355 if (fatal) { 3356 qcow2_mark_corrupt(bs); 3357 bs->drv = NULL; /* make BDS unusable */ 3358 } 3359 3360 s->signaled_corruption = true; 3361 } 3362 3363 static QemuOptsList qcow2_create_opts = { 3364 .name = "qcow2-create-opts", 3365 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head), 3366 .desc = { 3367 { 3368 .name = BLOCK_OPT_SIZE, 3369 .type = QEMU_OPT_SIZE, 3370 .help = "Virtual disk size" 3371 }, 3372 { 3373 .name = BLOCK_OPT_COMPAT_LEVEL, 3374 .type = QEMU_OPT_STRING, 3375 .help = "Compatibility level (0.10 or 1.1)" 3376 }, 3377 { 3378 .name = BLOCK_OPT_BACKING_FILE, 3379 .type = QEMU_OPT_STRING, 3380 .help = "File name of a base image" 3381 }, 3382 { 3383 .name = BLOCK_OPT_BACKING_FMT, 3384 .type = QEMU_OPT_STRING, 3385 .help = "Image format of the base image" 3386 }, 3387 { 3388 .name = BLOCK_OPT_ENCRYPT, 3389 .type = QEMU_OPT_BOOL, 3390 .help = "Encrypt the image", 3391 .def_value_str = "off" 3392 }, 3393 { 3394 .name = BLOCK_OPT_CLUSTER_SIZE, 3395 .type = QEMU_OPT_SIZE, 3396 .help = "qcow2 cluster size", 3397 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 3398 }, 3399 { 3400 .name = BLOCK_OPT_PREALLOC, 3401 .type = QEMU_OPT_STRING, 3402 .help = "Preallocation mode (allowed values: off, metadata, " 3403 "falloc, full)" 3404 }, 3405 { 3406 .name = BLOCK_OPT_LAZY_REFCOUNTS, 3407 .type = QEMU_OPT_BOOL, 3408 .help = "Postpone refcount updates", 3409 .def_value_str = "off" 3410 }, 3411 { 3412 .name = BLOCK_OPT_REFCOUNT_BITS, 3413 .type = QEMU_OPT_NUMBER, 3414 .help = "Width of a reference count entry in bits", 3415 .def_value_str = "16" 3416 }, 3417 { /* end of list */ } 3418 } 3419 }; 3420 3421 BlockDriver bdrv_qcow2 = { 3422 .format_name = "qcow2", 3423 .instance_size = sizeof(BDRVQcow2State), 3424 .bdrv_probe = qcow2_probe, 3425 .bdrv_open = qcow2_open, 3426 .bdrv_close = qcow2_close, 3427 .bdrv_reopen_prepare = qcow2_reopen_prepare, 3428 .bdrv_reopen_commit = qcow2_reopen_commit, 3429 .bdrv_reopen_abort = qcow2_reopen_abort, 3430 .bdrv_join_options = qcow2_join_options, 3431 .bdrv_child_perm = bdrv_format_default_perms, 3432 .bdrv_create = qcow2_create, 3433 .bdrv_has_zero_init = bdrv_has_zero_init_1, 3434 .bdrv_co_get_block_status = qcow2_co_get_block_status, 3435 .bdrv_set_key = qcow2_set_key, 3436 3437 .bdrv_co_preadv = qcow2_co_preadv, 3438 .bdrv_co_pwritev = qcow2_co_pwritev, 3439 .bdrv_co_flush_to_os = qcow2_co_flush_to_os, 3440 3441 .bdrv_co_pwrite_zeroes = qcow2_co_pwrite_zeroes, 3442 .bdrv_co_pdiscard = qcow2_co_pdiscard, 3443 .bdrv_truncate = qcow2_truncate, 3444 .bdrv_co_pwritev_compressed = qcow2_co_pwritev_compressed, 3445 .bdrv_make_empty = qcow2_make_empty, 3446 3447 .bdrv_snapshot_create = qcow2_snapshot_create, 3448 .bdrv_snapshot_goto = qcow2_snapshot_goto, 3449 .bdrv_snapshot_delete = qcow2_snapshot_delete, 3450 .bdrv_snapshot_list = qcow2_snapshot_list, 3451 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp, 3452 .bdrv_get_info = qcow2_get_info, 3453 .bdrv_get_specific_info = qcow2_get_specific_info, 3454 3455 .bdrv_save_vmstate = qcow2_save_vmstate, 3456 .bdrv_load_vmstate = qcow2_load_vmstate, 3457 3458 .supports_backing = true, 3459 .bdrv_change_backing_file = qcow2_change_backing_file, 3460 3461 .bdrv_refresh_limits = qcow2_refresh_limits, 3462 .bdrv_invalidate_cache = qcow2_invalidate_cache, 3463 .bdrv_inactivate = qcow2_inactivate, 3464 3465 .create_opts = &qcow2_create_opts, 3466 .bdrv_check = qcow2_check, 3467 .bdrv_amend_options = qcow2_amend_options, 3468 3469 .bdrv_detach_aio_context = qcow2_detach_aio_context, 3470 .bdrv_attach_aio_context = qcow2_attach_aio_context, 3471 }; 3472 3473 static void bdrv_qcow2_init(void) 3474 { 3475 bdrv_register(&bdrv_qcow2); 3476 } 3477 3478 block_init(bdrv_qcow2_init); 3479