1 /* 2 * Block driver for the Virtual Disk Image (VDI) format 3 * 4 * Copyright (c) 2009, 2012 Stefan Weil 5 * 6 * This program is free software: you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation, either version 2 of the License, or 9 * (at your option) version 3 or any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 * 19 * Reference: 20 * http://forums.virtualbox.org/viewtopic.php?t=8046 21 * 22 * This driver supports create / read / write operations on VDI images. 23 * 24 * Todo (see also TODO in code): 25 * 26 * Some features like snapshots are still missing. 27 * 28 * Deallocation of zero-filled blocks and shrinking images are missing, too 29 * (might be added to common block layer). 30 * 31 * Allocation of blocks could be optimized (less writes to block map and 32 * header). 33 * 34 * Read and write of adjacent blocks could be done in one operation 35 * (current code uses one operation per block (1 MiB). 36 * 37 * The code is not thread safe (missing locks for changes in header and 38 * block table, no problem with current QEMU). 39 * 40 * Hints: 41 * 42 * Blocks (VDI documentation) correspond to clusters (QEMU). 43 * QEMU's backing files could be implemented using VDI snapshot files (TODO). 44 * VDI snapshot files may also contain the complete machine state. 45 * Maybe this machine state can be converted to QEMU PC machine snapshot data. 46 * 47 * The driver keeps a block cache (little endian entries) in memory. 48 * For the standard block size (1 MiB), a 1 TiB disk will use 4 MiB RAM, 49 * so this seems to be reasonable. 50 */ 51 52 #include "qemu/osdep.h" 53 #include "qemu/units.h" 54 #include "qapi/error.h" 55 #include "qapi/qobject-input-visitor.h" 56 #include "qapi/qapi-visit-block-core.h" 57 #include "block/block_int.h" 58 #include "block/qdict.h" 59 #include "sysemu/block-backend.h" 60 #include "qemu/module.h" 61 #include "qemu/option.h" 62 #include "qemu/bswap.h" 63 #include "migration/blocker.h" 64 #include "qemu/coroutine.h" 65 #include "qemu/cutils.h" 66 #include "qemu/uuid.h" 67 68 /* Code configuration options. */ 69 70 /* Enable debug messages. */ 71 //~ #define CONFIG_VDI_DEBUG 72 73 /* Support write operations on VDI images. */ 74 #define CONFIG_VDI_WRITE 75 76 /* Support non-standard block (cluster) size. This is untested. 77 * Maybe it will be needed for very large images. 78 */ 79 //~ #define CONFIG_VDI_BLOCK_SIZE 80 81 /* Support static (fixed, pre-allocated) images. */ 82 #define CONFIG_VDI_STATIC_IMAGE 83 84 /* Command line option for static images. */ 85 #define BLOCK_OPT_STATIC "static" 86 87 #define SECTOR_SIZE 512 88 #define DEFAULT_CLUSTER_SIZE (1 * MiB) 89 90 #if defined(CONFIG_VDI_DEBUG) 91 #define VDI_DEBUG 1 92 #else 93 #define VDI_DEBUG 0 94 #endif 95 96 #define logout(fmt, ...) \ 97 do { \ 98 if (VDI_DEBUG) { \ 99 fprintf(stderr, "vdi\t%-24s" fmt, __func__, ##__VA_ARGS__); \ 100 } \ 101 } while (0) 102 103 /* Image signature. */ 104 #define VDI_SIGNATURE 0xbeda107f 105 106 /* Image version. */ 107 #define VDI_VERSION_1_1 0x00010001 108 109 /* Image type. */ 110 #define VDI_TYPE_DYNAMIC 1 111 #define VDI_TYPE_STATIC 2 112 113 /* Innotek / SUN images use these strings in header.text: 114 * "<<< innotek VirtualBox Disk Image >>>\n" 115 * "<<< Sun xVM VirtualBox Disk Image >>>\n" 116 * "<<< Sun VirtualBox Disk Image >>>\n" 117 * The value does not matter, so QEMU created images use a different text. 118 */ 119 #define VDI_TEXT "<<< QEMU VM Virtual Disk Image >>>\n" 120 121 /* A never-allocated block; semantically arbitrary content. */ 122 #define VDI_UNALLOCATED 0xffffffffU 123 124 /* A discarded (no longer allocated) block; semantically zero-filled. */ 125 #define VDI_DISCARDED 0xfffffffeU 126 127 #define VDI_IS_ALLOCATED(X) ((X) < VDI_DISCARDED) 128 129 /* The bmap will take up VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) bytes; since 130 * the bmap is read and written in a single operation, its size needs to be 131 * limited to INT_MAX; furthermore, when opening an image, the bmap size is 132 * rounded up to be aligned on BDRV_SECTOR_SIZE. 133 * Therefore this should satisfy the following: 134 * VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) + BDRV_SECTOR_SIZE == INT_MAX + 1 135 * (INT_MAX + 1 is the first value not representable as an int) 136 * This guarantees that any value below or equal to the constant will, when 137 * multiplied by sizeof(uint32_t) and rounded up to a BDRV_SECTOR_SIZE boundary, 138 * still be below or equal to INT_MAX. */ 139 #define VDI_BLOCKS_IN_IMAGE_MAX \ 140 ((unsigned)((INT_MAX + 1u - BDRV_SECTOR_SIZE) / sizeof(uint32_t))) 141 #define VDI_DISK_SIZE_MAX ((uint64_t)VDI_BLOCKS_IN_IMAGE_MAX * \ 142 (uint64_t)DEFAULT_CLUSTER_SIZE) 143 144 static QemuOptsList vdi_create_opts; 145 146 typedef struct { 147 char text[0x40]; 148 uint32_t signature; 149 uint32_t version; 150 uint32_t header_size; 151 uint32_t image_type; 152 uint32_t image_flags; 153 char description[256]; 154 uint32_t offset_bmap; 155 uint32_t offset_data; 156 uint32_t cylinders; /* disk geometry, unused here */ 157 uint32_t heads; /* disk geometry, unused here */ 158 uint32_t sectors; /* disk geometry, unused here */ 159 uint32_t sector_size; 160 uint32_t unused1; 161 uint64_t disk_size; 162 uint32_t block_size; 163 uint32_t block_extra; /* unused here */ 164 uint32_t blocks_in_image; 165 uint32_t blocks_allocated; 166 QemuUUID uuid_image; 167 QemuUUID uuid_last_snap; 168 QemuUUID uuid_link; 169 QemuUUID uuid_parent; 170 uint64_t unused2[7]; 171 } QEMU_PACKED VdiHeader; 172 173 typedef struct { 174 /* The block map entries are little endian (even in memory). */ 175 uint32_t *bmap; 176 /* Size of block (bytes). */ 177 uint32_t block_size; 178 /* First sector of block map. */ 179 uint32_t bmap_sector; 180 /* VDI header (converted to host endianness). */ 181 VdiHeader header; 182 183 CoRwlock bmap_lock; 184 185 Error *migration_blocker; 186 } BDRVVdiState; 187 188 static void vdi_header_to_cpu(VdiHeader *header) 189 { 190 le32_to_cpus(&header->signature); 191 le32_to_cpus(&header->version); 192 le32_to_cpus(&header->header_size); 193 le32_to_cpus(&header->image_type); 194 le32_to_cpus(&header->image_flags); 195 le32_to_cpus(&header->offset_bmap); 196 le32_to_cpus(&header->offset_data); 197 le32_to_cpus(&header->cylinders); 198 le32_to_cpus(&header->heads); 199 le32_to_cpus(&header->sectors); 200 le32_to_cpus(&header->sector_size); 201 le64_to_cpus(&header->disk_size); 202 le32_to_cpus(&header->block_size); 203 le32_to_cpus(&header->block_extra); 204 le32_to_cpus(&header->blocks_in_image); 205 le32_to_cpus(&header->blocks_allocated); 206 qemu_uuid_bswap(&header->uuid_image); 207 qemu_uuid_bswap(&header->uuid_last_snap); 208 qemu_uuid_bswap(&header->uuid_link); 209 qemu_uuid_bswap(&header->uuid_parent); 210 } 211 212 static void vdi_header_to_le(VdiHeader *header) 213 { 214 cpu_to_le32s(&header->signature); 215 cpu_to_le32s(&header->version); 216 cpu_to_le32s(&header->header_size); 217 cpu_to_le32s(&header->image_type); 218 cpu_to_le32s(&header->image_flags); 219 cpu_to_le32s(&header->offset_bmap); 220 cpu_to_le32s(&header->offset_data); 221 cpu_to_le32s(&header->cylinders); 222 cpu_to_le32s(&header->heads); 223 cpu_to_le32s(&header->sectors); 224 cpu_to_le32s(&header->sector_size); 225 cpu_to_le64s(&header->disk_size); 226 cpu_to_le32s(&header->block_size); 227 cpu_to_le32s(&header->block_extra); 228 cpu_to_le32s(&header->blocks_in_image); 229 cpu_to_le32s(&header->blocks_allocated); 230 qemu_uuid_bswap(&header->uuid_image); 231 qemu_uuid_bswap(&header->uuid_last_snap); 232 qemu_uuid_bswap(&header->uuid_link); 233 qemu_uuid_bswap(&header->uuid_parent); 234 } 235 236 static void vdi_header_print(VdiHeader *header) 237 { 238 char uuid[37]; 239 logout("text %s", header->text); 240 logout("signature 0x%08x\n", header->signature); 241 logout("header size 0x%04x\n", header->header_size); 242 logout("image type 0x%04x\n", header->image_type); 243 logout("image flags 0x%04x\n", header->image_flags); 244 logout("description %s\n", header->description); 245 logout("offset bmap 0x%04x\n", header->offset_bmap); 246 logout("offset data 0x%04x\n", header->offset_data); 247 logout("cylinders 0x%04x\n", header->cylinders); 248 logout("heads 0x%04x\n", header->heads); 249 logout("sectors 0x%04x\n", header->sectors); 250 logout("sector size 0x%04x\n", header->sector_size); 251 logout("image size 0x%" PRIx64 " B (%" PRIu64 " MiB)\n", 252 header->disk_size, header->disk_size / MiB); 253 logout("block size 0x%04x\n", header->block_size); 254 logout("block extra 0x%04x\n", header->block_extra); 255 logout("blocks tot. 0x%04x\n", header->blocks_in_image); 256 logout("blocks all. 0x%04x\n", header->blocks_allocated); 257 qemu_uuid_unparse(&header->uuid_image, uuid); 258 logout("uuid image %s\n", uuid); 259 qemu_uuid_unparse(&header->uuid_last_snap, uuid); 260 logout("uuid snap %s\n", uuid); 261 qemu_uuid_unparse(&header->uuid_link, uuid); 262 logout("uuid link %s\n", uuid); 263 qemu_uuid_unparse(&header->uuid_parent, uuid); 264 logout("uuid parent %s\n", uuid); 265 } 266 267 static int coroutine_fn vdi_co_check(BlockDriverState *bs, BdrvCheckResult *res, 268 BdrvCheckMode fix) 269 { 270 /* TODO: additional checks possible. */ 271 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 272 uint32_t blocks_allocated = 0; 273 uint32_t block; 274 uint32_t *bmap; 275 logout("\n"); 276 277 if (fix) { 278 return -ENOTSUP; 279 } 280 281 bmap = g_try_new(uint32_t, s->header.blocks_in_image); 282 if (s->header.blocks_in_image && bmap == NULL) { 283 res->check_errors++; 284 return -ENOMEM; 285 } 286 287 memset(bmap, 0xff, s->header.blocks_in_image * sizeof(uint32_t)); 288 289 /* Check block map and value of blocks_allocated. */ 290 for (block = 0; block < s->header.blocks_in_image; block++) { 291 uint32_t bmap_entry = le32_to_cpu(s->bmap[block]); 292 if (VDI_IS_ALLOCATED(bmap_entry)) { 293 if (bmap_entry < s->header.blocks_in_image) { 294 blocks_allocated++; 295 if (!VDI_IS_ALLOCATED(bmap[bmap_entry])) { 296 bmap[bmap_entry] = bmap_entry; 297 } else { 298 fprintf(stderr, "ERROR: block index %" PRIu32 299 " also used by %" PRIu32 "\n", bmap[bmap_entry], bmap_entry); 300 res->corruptions++; 301 } 302 } else { 303 fprintf(stderr, "ERROR: block index %" PRIu32 304 " too large, is %" PRIu32 "\n", block, bmap_entry); 305 res->corruptions++; 306 } 307 } 308 } 309 if (blocks_allocated != s->header.blocks_allocated) { 310 fprintf(stderr, "ERROR: allocated blocks mismatch, is %" PRIu32 311 ", should be %" PRIu32 "\n", 312 blocks_allocated, s->header.blocks_allocated); 313 res->corruptions++; 314 } 315 316 g_free(bmap); 317 318 return 0; 319 } 320 321 static int vdi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 322 { 323 /* TODO: vdi_get_info would be needed for machine snapshots. 324 vm_state_offset is still missing. */ 325 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 326 logout("\n"); 327 bdi->cluster_size = s->block_size; 328 bdi->vm_state_offset = 0; 329 bdi->unallocated_blocks_are_zero = true; 330 return 0; 331 } 332 333 static int vdi_make_empty(BlockDriverState *bs) 334 { 335 /* TODO: missing code. */ 336 logout("\n"); 337 /* The return value for missing code must be 0, see block.c. */ 338 return 0; 339 } 340 341 static int vdi_probe(const uint8_t *buf, int buf_size, const char *filename) 342 { 343 const VdiHeader *header = (const VdiHeader *)buf; 344 int ret = 0; 345 346 logout("\n"); 347 348 if (buf_size < sizeof(*header)) { 349 /* Header too small, no VDI. */ 350 } else if (le32_to_cpu(header->signature) == VDI_SIGNATURE) { 351 ret = 100; 352 } 353 354 if (ret == 0) { 355 logout("no vdi image\n"); 356 } else { 357 logout("%s", header->text); 358 } 359 360 return ret; 361 } 362 363 static int vdi_open(BlockDriverState *bs, QDict *options, int flags, 364 Error **errp) 365 { 366 BDRVVdiState *s = bs->opaque; 367 VdiHeader header; 368 size_t bmap_size; 369 int ret; 370 Error *local_err = NULL; 371 372 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 373 false, errp); 374 if (!bs->file) { 375 return -EINVAL; 376 } 377 378 logout("\n"); 379 380 ret = bdrv_read(bs->file, 0, (uint8_t *)&header, 1); 381 if (ret < 0) { 382 goto fail; 383 } 384 385 vdi_header_to_cpu(&header); 386 if (VDI_DEBUG) { 387 vdi_header_print(&header); 388 } 389 390 if (header.disk_size > VDI_DISK_SIZE_MAX) { 391 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64 392 ", max supported is 0x%" PRIx64 ")", 393 header.disk_size, VDI_DISK_SIZE_MAX); 394 ret = -ENOTSUP; 395 goto fail; 396 } 397 398 if (header.disk_size % SECTOR_SIZE != 0) { 399 /* 'VBoxManage convertfromraw' can create images with odd disk sizes. 400 We accept them but round the disk size to the next multiple of 401 SECTOR_SIZE. */ 402 logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size); 403 header.disk_size = ROUND_UP(header.disk_size, SECTOR_SIZE); 404 } 405 406 if (header.signature != VDI_SIGNATURE) { 407 error_setg(errp, "Image not in VDI format (bad signature %08" PRIx32 408 ")", header.signature); 409 ret = -EINVAL; 410 goto fail; 411 } else if (header.version != VDI_VERSION_1_1) { 412 error_setg(errp, "unsupported VDI image (version %" PRIu32 ".%" PRIu32 413 ")", header.version >> 16, header.version & 0xffff); 414 ret = -ENOTSUP; 415 goto fail; 416 } else if (header.offset_bmap % SECTOR_SIZE != 0) { 417 /* We only support block maps which start on a sector boundary. */ 418 error_setg(errp, "unsupported VDI image (unaligned block map offset " 419 "0x%" PRIx32 ")", header.offset_bmap); 420 ret = -ENOTSUP; 421 goto fail; 422 } else if (header.offset_data % SECTOR_SIZE != 0) { 423 /* We only support data blocks which start on a sector boundary. */ 424 error_setg(errp, "unsupported VDI image (unaligned data offset 0x%" 425 PRIx32 ")", header.offset_data); 426 ret = -ENOTSUP; 427 goto fail; 428 } else if (header.sector_size != SECTOR_SIZE) { 429 error_setg(errp, "unsupported VDI image (sector size %" PRIu32 430 " is not %u)", header.sector_size, SECTOR_SIZE); 431 ret = -ENOTSUP; 432 goto fail; 433 } else if (header.block_size != DEFAULT_CLUSTER_SIZE) { 434 error_setg(errp, "unsupported VDI image (block size %" PRIu32 435 " is not %" PRIu64 ")", 436 header.block_size, DEFAULT_CLUSTER_SIZE); 437 ret = -ENOTSUP; 438 goto fail; 439 } else if (header.disk_size > 440 (uint64_t)header.blocks_in_image * header.block_size) { 441 error_setg(errp, "unsupported VDI image (disk size %" PRIu64 ", " 442 "image bitmap has room for %" PRIu64 ")", 443 header.disk_size, 444 (uint64_t)header.blocks_in_image * header.block_size); 445 ret = -ENOTSUP; 446 goto fail; 447 } else if (!qemu_uuid_is_null(&header.uuid_link)) { 448 error_setg(errp, "unsupported VDI image (non-NULL link UUID)"); 449 ret = -ENOTSUP; 450 goto fail; 451 } else if (!qemu_uuid_is_null(&header.uuid_parent)) { 452 error_setg(errp, "unsupported VDI image (non-NULL parent UUID)"); 453 ret = -ENOTSUP; 454 goto fail; 455 } else if (header.blocks_in_image > VDI_BLOCKS_IN_IMAGE_MAX) { 456 error_setg(errp, "unsupported VDI image " 457 "(too many blocks %u, max is %u)", 458 header.blocks_in_image, VDI_BLOCKS_IN_IMAGE_MAX); 459 ret = -ENOTSUP; 460 goto fail; 461 } 462 463 bs->total_sectors = header.disk_size / SECTOR_SIZE; 464 465 s->block_size = header.block_size; 466 s->bmap_sector = header.offset_bmap / SECTOR_SIZE; 467 s->header = header; 468 469 bmap_size = header.blocks_in_image * sizeof(uint32_t); 470 bmap_size = DIV_ROUND_UP(bmap_size, SECTOR_SIZE); 471 s->bmap = qemu_try_blockalign(bs->file->bs, bmap_size * SECTOR_SIZE); 472 if (s->bmap == NULL) { 473 ret = -ENOMEM; 474 goto fail; 475 } 476 477 ret = bdrv_read(bs->file, s->bmap_sector, (uint8_t *)s->bmap, 478 bmap_size); 479 if (ret < 0) { 480 goto fail_free_bmap; 481 } 482 483 /* Disable migration when vdi images are used */ 484 error_setg(&s->migration_blocker, "The vdi format used by node '%s' " 485 "does not support live migration", 486 bdrv_get_device_or_node_name(bs)); 487 ret = migrate_add_blocker(s->migration_blocker, &local_err); 488 if (local_err) { 489 error_propagate(errp, local_err); 490 error_free(s->migration_blocker); 491 goto fail_free_bmap; 492 } 493 494 qemu_co_rwlock_init(&s->bmap_lock); 495 496 return 0; 497 498 fail_free_bmap: 499 qemu_vfree(s->bmap); 500 501 fail: 502 return ret; 503 } 504 505 static int vdi_reopen_prepare(BDRVReopenState *state, 506 BlockReopenQueue *queue, Error **errp) 507 { 508 return 0; 509 } 510 511 static int coroutine_fn vdi_co_block_status(BlockDriverState *bs, 512 bool want_zero, 513 int64_t offset, int64_t bytes, 514 int64_t *pnum, int64_t *map, 515 BlockDriverState **file) 516 { 517 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 518 size_t bmap_index = offset / s->block_size; 519 size_t index_in_block = offset % s->block_size; 520 uint32_t bmap_entry = le32_to_cpu(s->bmap[bmap_index]); 521 int result; 522 523 logout("%p, %" PRId64 ", %" PRId64 ", %p\n", bs, offset, bytes, pnum); 524 *pnum = MIN(s->block_size - index_in_block, bytes); 525 result = VDI_IS_ALLOCATED(bmap_entry); 526 if (!result) { 527 return 0; 528 } 529 530 *map = s->header.offset_data + (uint64_t)bmap_entry * s->block_size + 531 index_in_block; 532 *file = bs->file->bs; 533 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 534 } 535 536 static int coroutine_fn 537 vdi_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 538 QEMUIOVector *qiov, int flags) 539 { 540 BDRVVdiState *s = bs->opaque; 541 QEMUIOVector local_qiov; 542 uint32_t bmap_entry; 543 uint32_t block_index; 544 uint32_t offset_in_block; 545 uint32_t n_bytes; 546 uint64_t bytes_done = 0; 547 int ret = 0; 548 549 logout("\n"); 550 551 qemu_iovec_init(&local_qiov, qiov->niov); 552 553 while (ret >= 0 && bytes > 0) { 554 block_index = offset / s->block_size; 555 offset_in_block = offset % s->block_size; 556 n_bytes = MIN(bytes, s->block_size - offset_in_block); 557 558 logout("will read %u bytes starting at offset %" PRIu64 "\n", 559 n_bytes, offset); 560 561 /* prepare next AIO request */ 562 qemu_co_rwlock_rdlock(&s->bmap_lock); 563 bmap_entry = le32_to_cpu(s->bmap[block_index]); 564 qemu_co_rwlock_unlock(&s->bmap_lock); 565 if (!VDI_IS_ALLOCATED(bmap_entry)) { 566 /* Block not allocated, return zeros, no need to wait. */ 567 qemu_iovec_memset(qiov, bytes_done, 0, n_bytes); 568 ret = 0; 569 } else { 570 uint64_t data_offset = s->header.offset_data + 571 (uint64_t)bmap_entry * s->block_size + 572 offset_in_block; 573 574 qemu_iovec_reset(&local_qiov); 575 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); 576 577 ret = bdrv_co_preadv(bs->file, data_offset, n_bytes, 578 &local_qiov, 0); 579 } 580 logout("%u bytes read\n", n_bytes); 581 582 bytes -= n_bytes; 583 offset += n_bytes; 584 bytes_done += n_bytes; 585 } 586 587 qemu_iovec_destroy(&local_qiov); 588 589 return ret; 590 } 591 592 static int coroutine_fn 593 vdi_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 594 QEMUIOVector *qiov, int flags) 595 { 596 BDRVVdiState *s = bs->opaque; 597 QEMUIOVector local_qiov; 598 uint32_t bmap_entry; 599 uint32_t block_index; 600 uint32_t offset_in_block; 601 uint32_t n_bytes; 602 uint64_t data_offset; 603 uint32_t bmap_first = VDI_UNALLOCATED; 604 uint32_t bmap_last = VDI_UNALLOCATED; 605 uint8_t *block = NULL; 606 uint64_t bytes_done = 0; 607 int ret = 0; 608 609 logout("\n"); 610 611 qemu_iovec_init(&local_qiov, qiov->niov); 612 613 while (ret >= 0 && bytes > 0) { 614 block_index = offset / s->block_size; 615 offset_in_block = offset % s->block_size; 616 n_bytes = MIN(bytes, s->block_size - offset_in_block); 617 618 logout("will write %u bytes starting at offset %" PRIu64 "\n", 619 n_bytes, offset); 620 621 /* prepare next AIO request */ 622 qemu_co_rwlock_rdlock(&s->bmap_lock); 623 bmap_entry = le32_to_cpu(s->bmap[block_index]); 624 if (!VDI_IS_ALLOCATED(bmap_entry)) { 625 /* Allocate new block and write to it. */ 626 uint64_t data_offset; 627 qemu_co_rwlock_upgrade(&s->bmap_lock); 628 bmap_entry = le32_to_cpu(s->bmap[block_index]); 629 if (VDI_IS_ALLOCATED(bmap_entry)) { 630 /* A concurrent allocation did the work for us. */ 631 qemu_co_rwlock_downgrade(&s->bmap_lock); 632 goto nonallocating_write; 633 } 634 635 bmap_entry = s->header.blocks_allocated; 636 s->bmap[block_index] = cpu_to_le32(bmap_entry); 637 s->header.blocks_allocated++; 638 data_offset = s->header.offset_data + 639 (uint64_t)bmap_entry * s->block_size; 640 if (block == NULL) { 641 block = g_malloc(s->block_size); 642 bmap_first = block_index; 643 } 644 bmap_last = block_index; 645 /* Copy data to be written to new block and zero unused parts. */ 646 memset(block, 0, offset_in_block); 647 qemu_iovec_to_buf(qiov, bytes_done, block + offset_in_block, 648 n_bytes); 649 memset(block + offset_in_block + n_bytes, 0, 650 s->block_size - n_bytes - offset_in_block); 651 652 /* Write the new block under CoRwLock write-side protection, 653 * so this full-cluster write does not overlap a partial write 654 * of the same cluster, issued from the "else" branch. 655 */ 656 ret = bdrv_pwrite(bs->file, data_offset, block, s->block_size); 657 qemu_co_rwlock_unlock(&s->bmap_lock); 658 } else { 659 nonallocating_write: 660 data_offset = s->header.offset_data + 661 (uint64_t)bmap_entry * s->block_size + 662 offset_in_block; 663 qemu_co_rwlock_unlock(&s->bmap_lock); 664 665 qemu_iovec_reset(&local_qiov); 666 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); 667 668 ret = bdrv_co_pwritev(bs->file, data_offset, n_bytes, 669 &local_qiov, 0); 670 } 671 672 bytes -= n_bytes; 673 offset += n_bytes; 674 bytes_done += n_bytes; 675 676 logout("%u bytes written\n", n_bytes); 677 } 678 679 qemu_iovec_destroy(&local_qiov); 680 681 logout("finished data write\n"); 682 if (ret < 0) { 683 return ret; 684 } 685 686 if (block) { 687 /* One or more new blocks were allocated. */ 688 VdiHeader *header = (VdiHeader *) block; 689 uint8_t *base; 690 uint64_t offset; 691 uint32_t n_sectors; 692 693 logout("now writing modified header\n"); 694 assert(VDI_IS_ALLOCATED(bmap_first)); 695 *header = s->header; 696 vdi_header_to_le(header); 697 ret = bdrv_write(bs->file, 0, block, 1); 698 g_free(block); 699 block = NULL; 700 701 if (ret < 0) { 702 return ret; 703 } 704 705 logout("now writing modified block map entry %u...%u\n", 706 bmap_first, bmap_last); 707 /* Write modified sectors from block map. */ 708 bmap_first /= (SECTOR_SIZE / sizeof(uint32_t)); 709 bmap_last /= (SECTOR_SIZE / sizeof(uint32_t)); 710 n_sectors = bmap_last - bmap_first + 1; 711 offset = s->bmap_sector + bmap_first; 712 base = ((uint8_t *)&s->bmap[0]) + bmap_first * SECTOR_SIZE; 713 logout("will write %u block map sectors starting from entry %u\n", 714 n_sectors, bmap_first); 715 ret = bdrv_write(bs->file, offset, base, n_sectors); 716 } 717 718 return ret; 719 } 720 721 static int coroutine_fn vdi_co_do_create(BlockdevCreateOptions *create_options, 722 size_t block_size, Error **errp) 723 { 724 BlockdevCreateOptionsVdi *vdi_opts; 725 int ret = 0; 726 uint64_t bytes = 0; 727 uint32_t blocks; 728 uint32_t image_type; 729 VdiHeader header; 730 size_t i; 731 size_t bmap_size; 732 int64_t offset = 0; 733 BlockDriverState *bs_file = NULL; 734 BlockBackend *blk = NULL; 735 uint32_t *bmap = NULL; 736 737 assert(create_options->driver == BLOCKDEV_DRIVER_VDI); 738 vdi_opts = &create_options->u.vdi; 739 740 logout("\n"); 741 742 /* Validate options and set default values */ 743 bytes = vdi_opts->size; 744 745 if (!vdi_opts->has_preallocation) { 746 vdi_opts->preallocation = PREALLOC_MODE_OFF; 747 } 748 switch (vdi_opts->preallocation) { 749 case PREALLOC_MODE_OFF: 750 image_type = VDI_TYPE_DYNAMIC; 751 break; 752 case PREALLOC_MODE_METADATA: 753 image_type = VDI_TYPE_STATIC; 754 break; 755 default: 756 error_setg(errp, "Preallocation mode not supported for vdi"); 757 return -EINVAL; 758 } 759 760 #ifndef CONFIG_VDI_STATIC_IMAGE 761 if (image_type == VDI_TYPE_STATIC) { 762 ret = -ENOTSUP; 763 error_setg(errp, "Statically allocated images cannot be created in " 764 "this build"); 765 goto exit; 766 } 767 #endif 768 #ifndef CONFIG_VDI_BLOCK_SIZE 769 if (block_size != DEFAULT_CLUSTER_SIZE) { 770 ret = -ENOTSUP; 771 error_setg(errp, 772 "A non-default cluster size is not supported in this build"); 773 goto exit; 774 } 775 #endif 776 777 if (bytes > VDI_DISK_SIZE_MAX) { 778 ret = -ENOTSUP; 779 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64 780 ", max supported is 0x%" PRIx64 ")", 781 bytes, VDI_DISK_SIZE_MAX); 782 goto exit; 783 } 784 785 /* Create BlockBackend to write to the image */ 786 bs_file = bdrv_open_blockdev_ref(vdi_opts->file, errp); 787 if (!bs_file) { 788 ret = -EIO; 789 goto exit; 790 } 791 792 blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 793 ret = blk_insert_bs(blk, bs_file, errp); 794 if (ret < 0) { 795 goto exit; 796 } 797 798 blk_set_allow_write_beyond_eof(blk, true); 799 800 /* We need enough blocks to store the given disk size, 801 so always round up. */ 802 blocks = DIV_ROUND_UP(bytes, block_size); 803 804 bmap_size = blocks * sizeof(uint32_t); 805 bmap_size = ROUND_UP(bmap_size, SECTOR_SIZE); 806 807 memset(&header, 0, sizeof(header)); 808 pstrcpy(header.text, sizeof(header.text), VDI_TEXT); 809 header.signature = VDI_SIGNATURE; 810 header.version = VDI_VERSION_1_1; 811 header.header_size = 0x180; 812 header.image_type = image_type; 813 header.offset_bmap = 0x200; 814 header.offset_data = 0x200 + bmap_size; 815 header.sector_size = SECTOR_SIZE; 816 header.disk_size = bytes; 817 header.block_size = block_size; 818 header.blocks_in_image = blocks; 819 if (image_type == VDI_TYPE_STATIC) { 820 header.blocks_allocated = blocks; 821 } 822 qemu_uuid_generate(&header.uuid_image); 823 qemu_uuid_generate(&header.uuid_last_snap); 824 /* There is no need to set header.uuid_link or header.uuid_parent here. */ 825 if (VDI_DEBUG) { 826 vdi_header_print(&header); 827 } 828 vdi_header_to_le(&header); 829 ret = blk_pwrite(blk, offset, &header, sizeof(header), 0); 830 if (ret < 0) { 831 error_setg(errp, "Error writing header"); 832 goto exit; 833 } 834 offset += sizeof(header); 835 836 if (bmap_size > 0) { 837 bmap = g_try_malloc0(bmap_size); 838 if (bmap == NULL) { 839 ret = -ENOMEM; 840 error_setg(errp, "Could not allocate bmap"); 841 goto exit; 842 } 843 for (i = 0; i < blocks; i++) { 844 if (image_type == VDI_TYPE_STATIC) { 845 bmap[i] = i; 846 } else { 847 bmap[i] = VDI_UNALLOCATED; 848 } 849 } 850 ret = blk_pwrite(blk, offset, bmap, bmap_size, 0); 851 if (ret < 0) { 852 error_setg(errp, "Error writing bmap"); 853 goto exit; 854 } 855 offset += bmap_size; 856 } 857 858 if (image_type == VDI_TYPE_STATIC) { 859 ret = blk_truncate(blk, offset + blocks * block_size, 860 PREALLOC_MODE_OFF, errp); 861 if (ret < 0) { 862 error_prepend(errp, "Failed to statically allocate file"); 863 goto exit; 864 } 865 } 866 867 ret = 0; 868 exit: 869 blk_unref(blk); 870 bdrv_unref(bs_file); 871 g_free(bmap); 872 return ret; 873 } 874 875 static int coroutine_fn vdi_co_create(BlockdevCreateOptions *create_options, 876 Error **errp) 877 { 878 return vdi_co_do_create(create_options, DEFAULT_CLUSTER_SIZE, errp); 879 } 880 881 static int coroutine_fn vdi_co_create_opts(const char *filename, QemuOpts *opts, 882 Error **errp) 883 { 884 QDict *qdict = NULL; 885 BlockdevCreateOptions *create_options = NULL; 886 BlockDriverState *bs_file = NULL; 887 uint64_t block_size = DEFAULT_CLUSTER_SIZE; 888 bool is_static = false; 889 Visitor *v; 890 Error *local_err = NULL; 891 int ret; 892 893 /* Parse options and convert legacy syntax. 894 * 895 * Since CONFIG_VDI_BLOCK_SIZE is disabled by default, 896 * cluster-size is not part of the QAPI schema; therefore we have 897 * to parse it before creating the QAPI object. */ 898 #if defined(CONFIG_VDI_BLOCK_SIZE) 899 block_size = qemu_opt_get_size_del(opts, 900 BLOCK_OPT_CLUSTER_SIZE, 901 DEFAULT_CLUSTER_SIZE); 902 if (block_size < BDRV_SECTOR_SIZE || block_size > UINT32_MAX || 903 !is_power_of_2(block_size)) 904 { 905 error_setg(errp, "Invalid cluster size"); 906 ret = -EINVAL; 907 goto done; 908 } 909 #endif 910 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_STATIC, false)) { 911 is_static = true; 912 } 913 914 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vdi_create_opts, true); 915 916 /* Create and open the file (protocol layer) */ 917 ret = bdrv_create_file(filename, opts, errp); 918 if (ret < 0) { 919 goto done; 920 } 921 922 bs_file = bdrv_open(filename, NULL, NULL, 923 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 924 if (!bs_file) { 925 ret = -EIO; 926 goto done; 927 } 928 929 qdict_put_str(qdict, "driver", "vdi"); 930 qdict_put_str(qdict, "file", bs_file->node_name); 931 if (is_static) { 932 qdict_put_str(qdict, "preallocation", "metadata"); 933 } 934 935 /* Get the QAPI object */ 936 v = qobject_input_visitor_new_flat_confused(qdict, errp); 937 if (!v) { 938 ret = -EINVAL; 939 goto done; 940 } 941 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 942 visit_free(v); 943 944 if (local_err) { 945 error_propagate(errp, local_err); 946 ret = -EINVAL; 947 goto done; 948 } 949 950 /* Silently round up size */ 951 assert(create_options->driver == BLOCKDEV_DRIVER_VDI); 952 create_options->u.vdi.size = ROUND_UP(create_options->u.vdi.size, 953 BDRV_SECTOR_SIZE); 954 955 /* Create the vdi image (format layer) */ 956 ret = vdi_co_do_create(create_options, block_size, errp); 957 done: 958 qobject_unref(qdict); 959 qapi_free_BlockdevCreateOptions(create_options); 960 bdrv_unref(bs_file); 961 return ret; 962 } 963 964 static void vdi_close(BlockDriverState *bs) 965 { 966 BDRVVdiState *s = bs->opaque; 967 968 qemu_vfree(s->bmap); 969 970 migrate_del_blocker(s->migration_blocker); 971 error_free(s->migration_blocker); 972 } 973 974 static QemuOptsList vdi_create_opts = { 975 .name = "vdi-create-opts", 976 .head = QTAILQ_HEAD_INITIALIZER(vdi_create_opts.head), 977 .desc = { 978 { 979 .name = BLOCK_OPT_SIZE, 980 .type = QEMU_OPT_SIZE, 981 .help = "Virtual disk size" 982 }, 983 #if defined(CONFIG_VDI_BLOCK_SIZE) 984 { 985 .name = BLOCK_OPT_CLUSTER_SIZE, 986 .type = QEMU_OPT_SIZE, 987 .help = "VDI cluster (block) size", 988 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 989 }, 990 #endif 991 #if defined(CONFIG_VDI_STATIC_IMAGE) 992 { 993 .name = BLOCK_OPT_STATIC, 994 .type = QEMU_OPT_BOOL, 995 .help = "VDI static (pre-allocated) image", 996 .def_value_str = "off" 997 }, 998 #endif 999 /* TODO: An additional option to set UUID values might be useful. */ 1000 { /* end of list */ } 1001 } 1002 }; 1003 1004 static BlockDriver bdrv_vdi = { 1005 .format_name = "vdi", 1006 .instance_size = sizeof(BDRVVdiState), 1007 .bdrv_probe = vdi_probe, 1008 .bdrv_open = vdi_open, 1009 .bdrv_close = vdi_close, 1010 .bdrv_reopen_prepare = vdi_reopen_prepare, 1011 .bdrv_child_perm = bdrv_format_default_perms, 1012 .bdrv_co_create = vdi_co_create, 1013 .bdrv_co_create_opts = vdi_co_create_opts, 1014 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1015 .bdrv_co_block_status = vdi_co_block_status, 1016 .bdrv_make_empty = vdi_make_empty, 1017 1018 .bdrv_co_preadv = vdi_co_preadv, 1019 #if defined(CONFIG_VDI_WRITE) 1020 .bdrv_co_pwritev = vdi_co_pwritev, 1021 #endif 1022 1023 .bdrv_get_info = vdi_get_info, 1024 1025 .create_opts = &vdi_create_opts, 1026 .bdrv_co_check = vdi_co_check, 1027 }; 1028 1029 static void bdrv_vdi_init(void) 1030 { 1031 logout("\n"); 1032 bdrv_register(&bdrv_vdi); 1033 } 1034 1035 block_init(bdrv_vdi_init); 1036