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 #include "qemu/memalign.h" 68 69 /* Code configuration options. */ 70 71 /* Enable debug messages. */ 72 //~ #define CONFIG_VDI_DEBUG 73 74 /* Support write operations on VDI images. */ 75 #define CONFIG_VDI_WRITE 76 77 /* Support non-standard block (cluster) size. This is untested. 78 * Maybe it will be needed for very large images. 79 */ 80 //~ #define CONFIG_VDI_BLOCK_SIZE 81 82 /* Support static (fixed, pre-allocated) images. */ 83 #define CONFIG_VDI_STATIC_IMAGE 84 85 /* Command line option for static images. */ 86 #define BLOCK_OPT_STATIC "static" 87 88 #define SECTOR_SIZE 512 89 #define DEFAULT_CLUSTER_SIZE 1048576 90 /* Note: can't use 1 * MiB, because it's passed to stringify() */ 91 92 #if defined(CONFIG_VDI_DEBUG) 93 #define VDI_DEBUG 1 94 #else 95 #define VDI_DEBUG 0 96 #endif 97 98 #define logout(fmt, ...) \ 99 do { \ 100 if (VDI_DEBUG) { \ 101 fprintf(stderr, "vdi\t%-24s" fmt, __func__, ##__VA_ARGS__); \ 102 } \ 103 } while (0) 104 105 /* Image signature. */ 106 #define VDI_SIGNATURE 0xbeda107f 107 108 /* Image version. */ 109 #define VDI_VERSION_1_1 0x00010001 110 111 /* Image type. */ 112 #define VDI_TYPE_DYNAMIC 1 113 #define VDI_TYPE_STATIC 2 114 115 /* Innotek / SUN images use these strings in header.text: 116 * "<<< innotek VirtualBox Disk Image >>>\n" 117 * "<<< Sun xVM VirtualBox Disk Image >>>\n" 118 * "<<< Sun VirtualBox Disk Image >>>\n" 119 * The value does not matter, so QEMU created images use a different text. 120 */ 121 #define VDI_TEXT "<<< QEMU VM Virtual Disk Image >>>\n" 122 123 /* A never-allocated block; semantically arbitrary content. */ 124 #define VDI_UNALLOCATED 0xffffffffU 125 126 /* A discarded (no longer allocated) block; semantically zero-filled. */ 127 #define VDI_DISCARDED 0xfffffffeU 128 129 #define VDI_IS_ALLOCATED(X) ((X) < VDI_DISCARDED) 130 131 /* The bmap will take up VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) bytes; since 132 * the bmap is read and written in a single operation, its size needs to be 133 * limited to INT_MAX; furthermore, when opening an image, the bmap size is 134 * rounded up to be aligned on BDRV_SECTOR_SIZE. 135 * Therefore this should satisfy the following: 136 * VDI_BLOCKS_IN_IMAGE_MAX * sizeof(uint32_t) + BDRV_SECTOR_SIZE == INT_MAX + 1 137 * (INT_MAX + 1 is the first value not representable as an int) 138 * This guarantees that any value below or equal to the constant will, when 139 * multiplied by sizeof(uint32_t) and rounded up to a BDRV_SECTOR_SIZE boundary, 140 * still be below or equal to INT_MAX. */ 141 #define VDI_BLOCKS_IN_IMAGE_MAX \ 142 ((unsigned)((INT_MAX + 1u - BDRV_SECTOR_SIZE) / sizeof(uint32_t))) 143 #define VDI_DISK_SIZE_MAX ((uint64_t)VDI_BLOCKS_IN_IMAGE_MAX * \ 144 (uint64_t)DEFAULT_CLUSTER_SIZE) 145 146 static QemuOptsList vdi_create_opts; 147 148 typedef struct { 149 char text[0x40]; 150 uint32_t signature; 151 uint32_t version; 152 uint32_t header_size; 153 uint32_t image_type; 154 uint32_t image_flags; 155 char description[256]; 156 uint32_t offset_bmap; 157 uint32_t offset_data; 158 uint32_t cylinders; /* disk geometry, unused here */ 159 uint32_t heads; /* disk geometry, unused here */ 160 uint32_t sectors; /* disk geometry, unused here */ 161 uint32_t sector_size; 162 uint32_t unused1; 163 uint64_t disk_size; 164 uint32_t block_size; 165 uint32_t block_extra; /* unused here */ 166 uint32_t blocks_in_image; 167 uint32_t blocks_allocated; 168 QemuUUID uuid_image; 169 QemuUUID uuid_last_snap; 170 QemuUUID uuid_link; 171 QemuUUID uuid_parent; 172 uint64_t unused2[7]; 173 } QEMU_PACKED VdiHeader; 174 175 QEMU_BUILD_BUG_ON(sizeof(VdiHeader) != 512); 176 177 typedef struct { 178 /* The block map entries are little endian (even in memory). */ 179 uint32_t *bmap; 180 /* Size of block (bytes). */ 181 uint32_t block_size; 182 /* First sector of block map. */ 183 uint32_t bmap_sector; 184 /* VDI header (converted to host endianness). */ 185 VdiHeader header; 186 187 CoRwlock bmap_lock; 188 189 Error *migration_blocker; 190 } BDRVVdiState; 191 192 static void vdi_header_to_cpu(VdiHeader *header) 193 { 194 header->signature = le32_to_cpu(header->signature); 195 header->version = le32_to_cpu(header->version); 196 header->header_size = le32_to_cpu(header->header_size); 197 header->image_type = le32_to_cpu(header->image_type); 198 header->image_flags = le32_to_cpu(header->image_flags); 199 header->offset_bmap = le32_to_cpu(header->offset_bmap); 200 header->offset_data = le32_to_cpu(header->offset_data); 201 header->cylinders = le32_to_cpu(header->cylinders); 202 header->heads = le32_to_cpu(header->heads); 203 header->sectors = le32_to_cpu(header->sectors); 204 header->sector_size = le32_to_cpu(header->sector_size); 205 header->disk_size = le64_to_cpu(header->disk_size); 206 header->block_size = le32_to_cpu(header->block_size); 207 header->block_extra = le32_to_cpu(header->block_extra); 208 header->blocks_in_image = le32_to_cpu(header->blocks_in_image); 209 header->blocks_allocated = le32_to_cpu(header->blocks_allocated); 210 header->uuid_image = qemu_uuid_bswap(header->uuid_image); 211 header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap); 212 header->uuid_link = qemu_uuid_bswap(header->uuid_link); 213 header->uuid_parent = qemu_uuid_bswap(header->uuid_parent); 214 } 215 216 static void vdi_header_to_le(VdiHeader *header) 217 { 218 header->signature = cpu_to_le32(header->signature); 219 header->version = cpu_to_le32(header->version); 220 header->header_size = cpu_to_le32(header->header_size); 221 header->image_type = cpu_to_le32(header->image_type); 222 header->image_flags = cpu_to_le32(header->image_flags); 223 header->offset_bmap = cpu_to_le32(header->offset_bmap); 224 header->offset_data = cpu_to_le32(header->offset_data); 225 header->cylinders = cpu_to_le32(header->cylinders); 226 header->heads = cpu_to_le32(header->heads); 227 header->sectors = cpu_to_le32(header->sectors); 228 header->sector_size = cpu_to_le32(header->sector_size); 229 header->disk_size = cpu_to_le64(header->disk_size); 230 header->block_size = cpu_to_le32(header->block_size); 231 header->block_extra = cpu_to_le32(header->block_extra); 232 header->blocks_in_image = cpu_to_le32(header->blocks_in_image); 233 header->blocks_allocated = cpu_to_le32(header->blocks_allocated); 234 header->uuid_image = qemu_uuid_bswap(header->uuid_image); 235 header->uuid_last_snap = qemu_uuid_bswap(header->uuid_last_snap); 236 header->uuid_link = qemu_uuid_bswap(header->uuid_link); 237 header->uuid_parent = qemu_uuid_bswap(header->uuid_parent); 238 } 239 240 static void vdi_header_print(VdiHeader *header) 241 { 242 char uuidstr[37]; 243 QemuUUID uuid; 244 logout("text %s", header->text); 245 logout("signature 0x%08x\n", header->signature); 246 logout("header size 0x%04x\n", header->header_size); 247 logout("image type 0x%04x\n", header->image_type); 248 logout("image flags 0x%04x\n", header->image_flags); 249 logout("description %s\n", header->description); 250 logout("offset bmap 0x%04x\n", header->offset_bmap); 251 logout("offset data 0x%04x\n", header->offset_data); 252 logout("cylinders 0x%04x\n", header->cylinders); 253 logout("heads 0x%04x\n", header->heads); 254 logout("sectors 0x%04x\n", header->sectors); 255 logout("sector size 0x%04x\n", header->sector_size); 256 logout("image size 0x%" PRIx64 " B (%" PRIu64 " MiB)\n", 257 header->disk_size, header->disk_size / MiB); 258 logout("block size 0x%04x\n", header->block_size); 259 logout("block extra 0x%04x\n", header->block_extra); 260 logout("blocks tot. 0x%04x\n", header->blocks_in_image); 261 logout("blocks all. 0x%04x\n", header->blocks_allocated); 262 uuid = header->uuid_image; 263 qemu_uuid_unparse(&uuid, uuidstr); 264 logout("uuid image %s\n", uuidstr); 265 uuid = header->uuid_last_snap; 266 qemu_uuid_unparse(&uuid, uuidstr); 267 logout("uuid snap %s\n", uuidstr); 268 uuid = header->uuid_link; 269 qemu_uuid_unparse(&uuid, uuidstr); 270 logout("uuid link %s\n", uuidstr); 271 uuid = header->uuid_parent; 272 qemu_uuid_unparse(&uuid, uuidstr); 273 logout("uuid parent %s\n", uuidstr); 274 } 275 276 static int coroutine_fn vdi_co_check(BlockDriverState *bs, BdrvCheckResult *res, 277 BdrvCheckMode fix) 278 { 279 /* TODO: additional checks possible. */ 280 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 281 uint32_t blocks_allocated = 0; 282 uint32_t block; 283 uint32_t *bmap; 284 logout("\n"); 285 286 if (fix) { 287 return -ENOTSUP; 288 } 289 290 bmap = g_try_new(uint32_t, s->header.blocks_in_image); 291 if (s->header.blocks_in_image && bmap == NULL) { 292 res->check_errors++; 293 return -ENOMEM; 294 } 295 296 memset(bmap, 0xff, s->header.blocks_in_image * sizeof(uint32_t)); 297 298 /* Check block map and value of blocks_allocated. */ 299 for (block = 0; block < s->header.blocks_in_image; block++) { 300 uint32_t bmap_entry = le32_to_cpu(s->bmap[block]); 301 if (VDI_IS_ALLOCATED(bmap_entry)) { 302 if (bmap_entry < s->header.blocks_in_image) { 303 blocks_allocated++; 304 if (!VDI_IS_ALLOCATED(bmap[bmap_entry])) { 305 bmap[bmap_entry] = bmap_entry; 306 } else { 307 fprintf(stderr, "ERROR: block index %" PRIu32 308 " also used by %" PRIu32 "\n", bmap[bmap_entry], bmap_entry); 309 res->corruptions++; 310 } 311 } else { 312 fprintf(stderr, "ERROR: block index %" PRIu32 313 " too large, is %" PRIu32 "\n", block, bmap_entry); 314 res->corruptions++; 315 } 316 } 317 } 318 if (blocks_allocated != s->header.blocks_allocated) { 319 fprintf(stderr, "ERROR: allocated blocks mismatch, is %" PRIu32 320 ", should be %" PRIu32 "\n", 321 blocks_allocated, s->header.blocks_allocated); 322 res->corruptions++; 323 } 324 325 g_free(bmap); 326 327 return 0; 328 } 329 330 static int coroutine_fn 331 vdi_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 332 { 333 /* TODO: vdi_co_get_info would be needed for machine snapshots. 334 vm_state_offset is still missing. */ 335 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 336 logout("\n"); 337 bdi->cluster_size = s->block_size; 338 bdi->vm_state_offset = 0; 339 return 0; 340 } 341 342 static int vdi_make_empty(BlockDriverState *bs) 343 { 344 /* TODO: missing code. */ 345 logout("\n"); 346 /* The return value for missing code must be 0, see block.c. */ 347 return 0; 348 } 349 350 static int vdi_probe(const uint8_t *buf, int buf_size, const char *filename) 351 { 352 const VdiHeader *header = (const VdiHeader *)buf; 353 int ret = 0; 354 355 logout("\n"); 356 357 if (buf_size < sizeof(*header)) { 358 /* Header too small, no VDI. */ 359 } else if (le32_to_cpu(header->signature) == VDI_SIGNATURE) { 360 ret = 100; 361 } 362 363 if (ret == 0) { 364 logout("no vdi image\n"); 365 } else { 366 logout("%s", header->text); 367 } 368 369 return ret; 370 } 371 372 static int vdi_open(BlockDriverState *bs, QDict *options, int flags, 373 Error **errp) 374 { 375 BDRVVdiState *s = bs->opaque; 376 VdiHeader header; 377 size_t bmap_size; 378 int ret; 379 QemuUUID uuid_link, uuid_parent; 380 381 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 382 if (ret < 0) { 383 return ret; 384 } 385 386 logout("\n"); 387 388 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0); 389 if (ret < 0) { 390 goto fail; 391 } 392 393 vdi_header_to_cpu(&header); 394 if (VDI_DEBUG) { 395 vdi_header_print(&header); 396 } 397 398 if (header.disk_size > VDI_DISK_SIZE_MAX) { 399 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64 400 ", max supported is 0x%" PRIx64 ")", 401 header.disk_size, VDI_DISK_SIZE_MAX); 402 ret = -ENOTSUP; 403 goto fail; 404 } 405 406 uuid_link = header.uuid_link; 407 uuid_parent = header.uuid_parent; 408 409 if (header.disk_size % SECTOR_SIZE != 0) { 410 /* 'VBoxManage convertfromraw' can create images with odd disk sizes. 411 We accept them but round the disk size to the next multiple of 412 SECTOR_SIZE. */ 413 logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size); 414 header.disk_size = ROUND_UP(header.disk_size, SECTOR_SIZE); 415 } 416 417 if (header.signature != VDI_SIGNATURE) { 418 error_setg(errp, "Image not in VDI format (bad signature %08" PRIx32 419 ")", header.signature); 420 ret = -EINVAL; 421 goto fail; 422 } else if (header.version != VDI_VERSION_1_1) { 423 error_setg(errp, "unsupported VDI image (version %" PRIu32 ".%" PRIu32 424 ")", header.version >> 16, header.version & 0xffff); 425 ret = -ENOTSUP; 426 goto fail; 427 } else if (header.offset_bmap % SECTOR_SIZE != 0) { 428 /* We only support block maps which start on a sector boundary. */ 429 error_setg(errp, "unsupported VDI image (unaligned block map offset " 430 "0x%" PRIx32 ")", header.offset_bmap); 431 ret = -ENOTSUP; 432 goto fail; 433 } else if (header.offset_data % SECTOR_SIZE != 0) { 434 /* We only support data blocks which start on a sector boundary. */ 435 error_setg(errp, "unsupported VDI image (unaligned data offset 0x%" 436 PRIx32 ")", header.offset_data); 437 ret = -ENOTSUP; 438 goto fail; 439 } else if (header.sector_size != SECTOR_SIZE) { 440 error_setg(errp, "unsupported VDI image (sector size %" PRIu32 441 " is not %u)", header.sector_size, SECTOR_SIZE); 442 ret = -ENOTSUP; 443 goto fail; 444 } else if (header.block_size != DEFAULT_CLUSTER_SIZE) { 445 error_setg(errp, "unsupported VDI image (block size %" PRIu32 446 " is not %" PRIu32 ")", 447 header.block_size, DEFAULT_CLUSTER_SIZE); 448 ret = -ENOTSUP; 449 goto fail; 450 } else if (header.disk_size > 451 (uint64_t)header.blocks_in_image * header.block_size) { 452 error_setg(errp, "unsupported VDI image (disk size %" PRIu64 ", " 453 "image bitmap has room for %" PRIu64 ")", 454 header.disk_size, 455 (uint64_t)header.blocks_in_image * header.block_size); 456 ret = -ENOTSUP; 457 goto fail; 458 } else if (!qemu_uuid_is_null(&uuid_link)) { 459 error_setg(errp, "unsupported VDI image (non-NULL link UUID)"); 460 ret = -ENOTSUP; 461 goto fail; 462 } else if (!qemu_uuid_is_null(&uuid_parent)) { 463 error_setg(errp, "unsupported VDI image (non-NULL parent UUID)"); 464 ret = -ENOTSUP; 465 goto fail; 466 } else if (header.blocks_in_image > VDI_BLOCKS_IN_IMAGE_MAX) { 467 error_setg(errp, "unsupported VDI image " 468 "(too many blocks %u, max is %u)", 469 header.blocks_in_image, VDI_BLOCKS_IN_IMAGE_MAX); 470 ret = -ENOTSUP; 471 goto fail; 472 } 473 474 bs->total_sectors = header.disk_size / SECTOR_SIZE; 475 476 s->block_size = header.block_size; 477 s->bmap_sector = header.offset_bmap / SECTOR_SIZE; 478 s->header = header; 479 480 bmap_size = header.blocks_in_image * sizeof(uint32_t); 481 bmap_size = DIV_ROUND_UP(bmap_size, SECTOR_SIZE); 482 s->bmap = qemu_try_blockalign(bs->file->bs, bmap_size * SECTOR_SIZE); 483 if (s->bmap == NULL) { 484 ret = -ENOMEM; 485 goto fail; 486 } 487 488 ret = bdrv_pread(bs->file, header.offset_bmap, bmap_size * SECTOR_SIZE, 489 s->bmap, 0); 490 if (ret < 0) { 491 goto fail_free_bmap; 492 } 493 494 /* Disable migration when vdi images are used */ 495 error_setg(&s->migration_blocker, "The vdi format used by node '%s' " 496 "does not support live migration", 497 bdrv_get_device_or_node_name(bs)); 498 ret = migrate_add_blocker(s->migration_blocker, errp); 499 if (ret < 0) { 500 error_free(s->migration_blocker); 501 goto fail_free_bmap; 502 } 503 504 qemu_co_rwlock_init(&s->bmap_lock); 505 506 return 0; 507 508 fail_free_bmap: 509 qemu_vfree(s->bmap); 510 511 fail: 512 return ret; 513 } 514 515 static int vdi_reopen_prepare(BDRVReopenState *state, 516 BlockReopenQueue *queue, Error **errp) 517 { 518 return 0; 519 } 520 521 static int coroutine_fn vdi_co_block_status(BlockDriverState *bs, 522 bool want_zero, 523 int64_t offset, int64_t bytes, 524 int64_t *pnum, int64_t *map, 525 BlockDriverState **file) 526 { 527 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 528 size_t bmap_index = offset / s->block_size; 529 size_t index_in_block = offset % s->block_size; 530 uint32_t bmap_entry = le32_to_cpu(s->bmap[bmap_index]); 531 int result; 532 533 logout("%p, %" PRId64 ", %" PRId64 ", %p\n", bs, offset, bytes, pnum); 534 *pnum = MIN(s->block_size - index_in_block, bytes); 535 result = VDI_IS_ALLOCATED(bmap_entry); 536 if (!result) { 537 return BDRV_BLOCK_ZERO; 538 } 539 540 *map = s->header.offset_data + (uint64_t)bmap_entry * s->block_size + 541 index_in_block; 542 *file = bs->file->bs; 543 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | 544 (s->header.image_type == VDI_TYPE_STATIC ? BDRV_BLOCK_RECURSE : 0); 545 } 546 547 static int coroutine_fn GRAPH_RDLOCK 548 vdi_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 549 QEMUIOVector *qiov, BdrvRequestFlags flags) 550 { 551 BDRVVdiState *s = bs->opaque; 552 QEMUIOVector local_qiov; 553 uint32_t bmap_entry; 554 uint32_t block_index; 555 uint32_t offset_in_block; 556 uint32_t n_bytes; 557 uint64_t bytes_done = 0; 558 int ret = 0; 559 560 logout("\n"); 561 562 qemu_iovec_init(&local_qiov, qiov->niov); 563 564 while (ret >= 0 && bytes > 0) { 565 block_index = offset / s->block_size; 566 offset_in_block = offset % s->block_size; 567 n_bytes = MIN(bytes, s->block_size - offset_in_block); 568 569 logout("will read %u bytes starting at offset %" PRIu64 "\n", 570 n_bytes, offset); 571 572 /* prepare next AIO request */ 573 qemu_co_rwlock_rdlock(&s->bmap_lock); 574 bmap_entry = le32_to_cpu(s->bmap[block_index]); 575 qemu_co_rwlock_unlock(&s->bmap_lock); 576 if (!VDI_IS_ALLOCATED(bmap_entry)) { 577 /* Block not allocated, return zeros, no need to wait. */ 578 qemu_iovec_memset(qiov, bytes_done, 0, n_bytes); 579 ret = 0; 580 } else { 581 uint64_t data_offset = s->header.offset_data + 582 (uint64_t)bmap_entry * s->block_size + 583 offset_in_block; 584 585 qemu_iovec_reset(&local_qiov); 586 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); 587 588 ret = bdrv_co_preadv(bs->file, data_offset, n_bytes, 589 &local_qiov, 0); 590 } 591 logout("%u bytes read\n", n_bytes); 592 593 bytes -= n_bytes; 594 offset += n_bytes; 595 bytes_done += n_bytes; 596 } 597 598 qemu_iovec_destroy(&local_qiov); 599 600 return ret; 601 } 602 603 static int coroutine_fn GRAPH_RDLOCK 604 vdi_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, 605 QEMUIOVector *qiov, BdrvRequestFlags flags) 606 { 607 BDRVVdiState *s = bs->opaque; 608 QEMUIOVector local_qiov; 609 uint32_t bmap_entry; 610 uint32_t block_index; 611 uint32_t offset_in_block; 612 uint32_t n_bytes; 613 uint64_t data_offset; 614 uint32_t bmap_first = VDI_UNALLOCATED; 615 uint32_t bmap_last = VDI_UNALLOCATED; 616 uint8_t *block = NULL; 617 uint64_t bytes_done = 0; 618 int ret = 0; 619 620 logout("\n"); 621 622 qemu_iovec_init(&local_qiov, qiov->niov); 623 624 while (ret >= 0 && bytes > 0) { 625 block_index = offset / s->block_size; 626 offset_in_block = offset % s->block_size; 627 n_bytes = MIN(bytes, s->block_size - offset_in_block); 628 629 logout("will write %u bytes starting at offset %" PRIu64 "\n", 630 n_bytes, offset); 631 632 /* prepare next AIO request */ 633 qemu_co_rwlock_rdlock(&s->bmap_lock); 634 bmap_entry = le32_to_cpu(s->bmap[block_index]); 635 if (!VDI_IS_ALLOCATED(bmap_entry)) { 636 /* Allocate new block and write to it. */ 637 uint64_t data_offset; 638 qemu_co_rwlock_upgrade(&s->bmap_lock); 639 bmap_entry = le32_to_cpu(s->bmap[block_index]); 640 if (VDI_IS_ALLOCATED(bmap_entry)) { 641 /* A concurrent allocation did the work for us. */ 642 qemu_co_rwlock_downgrade(&s->bmap_lock); 643 goto nonallocating_write; 644 } 645 646 bmap_entry = s->header.blocks_allocated; 647 s->bmap[block_index] = cpu_to_le32(bmap_entry); 648 s->header.blocks_allocated++; 649 data_offset = s->header.offset_data + 650 (uint64_t)bmap_entry * s->block_size; 651 if (block == NULL) { 652 block = g_malloc(s->block_size); 653 bmap_first = block_index; 654 } 655 bmap_last = block_index; 656 /* Copy data to be written to new block and zero unused parts. */ 657 memset(block, 0, offset_in_block); 658 qemu_iovec_to_buf(qiov, bytes_done, block + offset_in_block, 659 n_bytes); 660 memset(block + offset_in_block + n_bytes, 0, 661 s->block_size - n_bytes - offset_in_block); 662 663 /* Write the new block under CoRwLock write-side protection, 664 * so this full-cluster write does not overlap a partial write 665 * of the same cluster, issued from the "else" branch. 666 */ 667 ret = bdrv_co_pwrite(bs->file, data_offset, s->block_size, block, 668 0); 669 qemu_co_rwlock_unlock(&s->bmap_lock); 670 } else { 671 nonallocating_write: 672 data_offset = s->header.offset_data + 673 (uint64_t)bmap_entry * s->block_size + 674 offset_in_block; 675 qemu_co_rwlock_unlock(&s->bmap_lock); 676 677 qemu_iovec_reset(&local_qiov); 678 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); 679 680 ret = bdrv_co_pwritev(bs->file, data_offset, n_bytes, 681 &local_qiov, 0); 682 } 683 684 bytes -= n_bytes; 685 offset += n_bytes; 686 bytes_done += n_bytes; 687 688 logout("%u bytes written\n", n_bytes); 689 } 690 691 qemu_iovec_destroy(&local_qiov); 692 693 logout("finished data write\n"); 694 if (ret < 0) { 695 g_free(block); 696 return ret; 697 } 698 699 if (block) { 700 /* One or more new blocks were allocated. */ 701 VdiHeader *header; 702 uint8_t *base; 703 uint64_t offset; 704 uint32_t n_sectors; 705 706 g_free(block); 707 header = g_malloc(sizeof(*header)); 708 709 logout("now writing modified header\n"); 710 assert(VDI_IS_ALLOCATED(bmap_first)); 711 *header = s->header; 712 vdi_header_to_le(header); 713 ret = bdrv_co_pwrite(bs->file, 0, sizeof(*header), header, 0); 714 g_free(header); 715 716 if (ret < 0) { 717 return ret; 718 } 719 720 logout("now writing modified block map entry %u...%u\n", 721 bmap_first, bmap_last); 722 /* Write modified sectors from block map. */ 723 bmap_first /= (SECTOR_SIZE / sizeof(uint32_t)); 724 bmap_last /= (SECTOR_SIZE / sizeof(uint32_t)); 725 n_sectors = bmap_last - bmap_first + 1; 726 offset = s->bmap_sector + bmap_first; 727 base = ((uint8_t *)&s->bmap[0]) + bmap_first * SECTOR_SIZE; 728 logout("will write %u block map sectors starting from entry %u\n", 729 n_sectors, bmap_first); 730 ret = bdrv_co_pwrite(bs->file, offset * SECTOR_SIZE, 731 n_sectors * SECTOR_SIZE, base, 0); 732 } 733 734 return ret; 735 } 736 737 static int coroutine_fn vdi_co_do_create(BlockdevCreateOptions *create_options, 738 size_t block_size, Error **errp) 739 { 740 BlockdevCreateOptionsVdi *vdi_opts; 741 int ret = 0; 742 uint64_t bytes = 0; 743 uint32_t blocks; 744 uint32_t image_type; 745 VdiHeader header; 746 size_t i; 747 size_t bmap_size; 748 int64_t offset = 0; 749 BlockDriverState *bs_file = NULL; 750 BlockBackend *blk = NULL; 751 uint32_t *bmap = NULL; 752 QemuUUID uuid; 753 754 assert(create_options->driver == BLOCKDEV_DRIVER_VDI); 755 vdi_opts = &create_options->u.vdi; 756 757 logout("\n"); 758 759 /* Validate options and set default values */ 760 bytes = vdi_opts->size; 761 762 if (!vdi_opts->has_preallocation) { 763 vdi_opts->preallocation = PREALLOC_MODE_OFF; 764 } 765 switch (vdi_opts->preallocation) { 766 case PREALLOC_MODE_OFF: 767 image_type = VDI_TYPE_DYNAMIC; 768 break; 769 case PREALLOC_MODE_METADATA: 770 image_type = VDI_TYPE_STATIC; 771 break; 772 default: 773 error_setg(errp, "Preallocation mode not supported for vdi"); 774 return -EINVAL; 775 } 776 777 #ifndef CONFIG_VDI_STATIC_IMAGE 778 if (image_type == VDI_TYPE_STATIC) { 779 ret = -ENOTSUP; 780 error_setg(errp, "Statically allocated images cannot be created in " 781 "this build"); 782 goto exit; 783 } 784 #endif 785 #ifndef CONFIG_VDI_BLOCK_SIZE 786 if (block_size != DEFAULT_CLUSTER_SIZE) { 787 ret = -ENOTSUP; 788 error_setg(errp, 789 "A non-default cluster size is not supported in this build"); 790 goto exit; 791 } 792 #endif 793 794 if (bytes > VDI_DISK_SIZE_MAX) { 795 ret = -ENOTSUP; 796 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64 797 ", max supported is 0x%" PRIx64 ")", 798 bytes, VDI_DISK_SIZE_MAX); 799 goto exit; 800 } 801 802 /* Create BlockBackend to write to the image */ 803 bs_file = bdrv_co_open_blockdev_ref(vdi_opts->file, errp); 804 if (!bs_file) { 805 ret = -EIO; 806 goto exit; 807 } 808 809 blk = blk_co_new_with_bs(bs_file, BLK_PERM_WRITE | BLK_PERM_RESIZE, 810 BLK_PERM_ALL, errp); 811 if (!blk) { 812 ret = -EPERM; 813 goto exit; 814 } 815 816 blk_set_allow_write_beyond_eof(blk, true); 817 818 /* We need enough blocks to store the given disk size, 819 so always round up. */ 820 blocks = DIV_ROUND_UP(bytes, block_size); 821 822 bmap_size = blocks * sizeof(uint32_t); 823 bmap_size = ROUND_UP(bmap_size, SECTOR_SIZE); 824 825 memset(&header, 0, sizeof(header)); 826 pstrcpy(header.text, sizeof(header.text), VDI_TEXT); 827 header.signature = VDI_SIGNATURE; 828 header.version = VDI_VERSION_1_1; 829 header.header_size = 0x180; 830 header.image_type = image_type; 831 header.offset_bmap = 0x200; 832 header.offset_data = 0x200 + bmap_size; 833 header.sector_size = SECTOR_SIZE; 834 header.disk_size = bytes; 835 header.block_size = block_size; 836 header.blocks_in_image = blocks; 837 if (image_type == VDI_TYPE_STATIC) { 838 header.blocks_allocated = blocks; 839 } 840 qemu_uuid_generate(&uuid); 841 header.uuid_image = uuid; 842 qemu_uuid_generate(&uuid); 843 header.uuid_last_snap = uuid; 844 /* There is no need to set header.uuid_link or header.uuid_parent here. */ 845 if (VDI_DEBUG) { 846 vdi_header_print(&header); 847 } 848 vdi_header_to_le(&header); 849 ret = blk_co_pwrite(blk, offset, sizeof(header), &header, 0); 850 if (ret < 0) { 851 error_setg(errp, "Error writing header"); 852 goto exit; 853 } 854 offset += sizeof(header); 855 856 if (bmap_size > 0) { 857 bmap = g_try_malloc0(bmap_size); 858 if (bmap == NULL) { 859 ret = -ENOMEM; 860 error_setg(errp, "Could not allocate bmap"); 861 goto exit; 862 } 863 for (i = 0; i < blocks; i++) { 864 if (image_type == VDI_TYPE_STATIC) { 865 bmap[i] = i; 866 } else { 867 bmap[i] = VDI_UNALLOCATED; 868 } 869 } 870 ret = blk_co_pwrite(blk, offset, bmap_size, bmap, 0); 871 if (ret < 0) { 872 error_setg(errp, "Error writing bmap"); 873 goto exit; 874 } 875 offset += bmap_size; 876 } 877 878 if (image_type == VDI_TYPE_STATIC) { 879 ret = blk_co_truncate(blk, offset + blocks * block_size, false, 880 PREALLOC_MODE_OFF, 0, errp); 881 if (ret < 0) { 882 error_prepend(errp, "Failed to statically allocate file"); 883 goto exit; 884 } 885 } 886 887 ret = 0; 888 exit: 889 blk_unref(blk); 890 bdrv_unref(bs_file); 891 g_free(bmap); 892 return ret; 893 } 894 895 static int coroutine_fn vdi_co_create(BlockdevCreateOptions *create_options, 896 Error **errp) 897 { 898 return vdi_co_do_create(create_options, DEFAULT_CLUSTER_SIZE, errp); 899 } 900 901 static int coroutine_fn GRAPH_RDLOCK 902 vdi_co_create_opts(BlockDriver *drv, const char *filename, 903 QemuOpts *opts, Error **errp) 904 { 905 QDict *qdict = NULL; 906 BlockdevCreateOptions *create_options = NULL; 907 BlockDriverState *bs_file = NULL; 908 uint64_t block_size = DEFAULT_CLUSTER_SIZE; 909 bool is_static = false; 910 Visitor *v; 911 int ret; 912 913 /* Parse options and convert legacy syntax. 914 * 915 * Since CONFIG_VDI_BLOCK_SIZE is disabled by default, 916 * cluster-size is not part of the QAPI schema; therefore we have 917 * to parse it before creating the QAPI object. */ 918 #if defined(CONFIG_VDI_BLOCK_SIZE) 919 block_size = qemu_opt_get_size_del(opts, 920 BLOCK_OPT_CLUSTER_SIZE, 921 DEFAULT_CLUSTER_SIZE); 922 if (block_size < BDRV_SECTOR_SIZE || block_size > UINT32_MAX || 923 !is_power_of_2(block_size)) 924 { 925 error_setg(errp, "Invalid cluster size"); 926 ret = -EINVAL; 927 goto done; 928 } 929 #endif 930 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_STATIC, false)) { 931 is_static = true; 932 } 933 934 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vdi_create_opts, true); 935 936 /* Create and open the file (protocol layer) */ 937 ret = bdrv_co_create_file(filename, opts, errp); 938 if (ret < 0) { 939 goto done; 940 } 941 942 bs_file = bdrv_co_open(filename, NULL, NULL, 943 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 944 if (!bs_file) { 945 ret = -EIO; 946 goto done; 947 } 948 949 qdict_put_str(qdict, "driver", "vdi"); 950 qdict_put_str(qdict, "file", bs_file->node_name); 951 if (is_static) { 952 qdict_put_str(qdict, "preallocation", "metadata"); 953 } 954 955 /* Get the QAPI object */ 956 v = qobject_input_visitor_new_flat_confused(qdict, errp); 957 if (!v) { 958 ret = -EINVAL; 959 goto done; 960 } 961 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp); 962 visit_free(v); 963 if (!create_options) { 964 ret = -EINVAL; 965 goto done; 966 } 967 968 /* Silently round up size */ 969 assert(create_options->driver == BLOCKDEV_DRIVER_VDI); 970 create_options->u.vdi.size = ROUND_UP(create_options->u.vdi.size, 971 BDRV_SECTOR_SIZE); 972 973 /* Create the vdi image (format layer) */ 974 ret = vdi_co_do_create(create_options, block_size, errp); 975 done: 976 qobject_unref(qdict); 977 qapi_free_BlockdevCreateOptions(create_options); 978 bdrv_unref(bs_file); 979 return ret; 980 } 981 982 static void vdi_close(BlockDriverState *bs) 983 { 984 BDRVVdiState *s = bs->opaque; 985 986 qemu_vfree(s->bmap); 987 988 migrate_del_blocker(s->migration_blocker); 989 error_free(s->migration_blocker); 990 } 991 992 static int vdi_has_zero_init(BlockDriverState *bs) 993 { 994 BDRVVdiState *s = bs->opaque; 995 996 if (s->header.image_type == VDI_TYPE_STATIC) { 997 return bdrv_has_zero_init(bs->file->bs); 998 } else { 999 return 1; 1000 } 1001 } 1002 1003 static QemuOptsList vdi_create_opts = { 1004 .name = "vdi-create-opts", 1005 .head = QTAILQ_HEAD_INITIALIZER(vdi_create_opts.head), 1006 .desc = { 1007 { 1008 .name = BLOCK_OPT_SIZE, 1009 .type = QEMU_OPT_SIZE, 1010 .help = "Virtual disk size" 1011 }, 1012 #if defined(CONFIG_VDI_BLOCK_SIZE) 1013 { 1014 .name = BLOCK_OPT_CLUSTER_SIZE, 1015 .type = QEMU_OPT_SIZE, 1016 .help = "VDI cluster (block) size", 1017 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE) 1018 }, 1019 #endif 1020 #if defined(CONFIG_VDI_STATIC_IMAGE) 1021 { 1022 .name = BLOCK_OPT_STATIC, 1023 .type = QEMU_OPT_BOOL, 1024 .help = "VDI static (pre-allocated) image", 1025 .def_value_str = "off" 1026 }, 1027 #endif 1028 /* TODO: An additional option to set UUID values might be useful. */ 1029 { /* end of list */ } 1030 } 1031 }; 1032 1033 static BlockDriver bdrv_vdi = { 1034 .format_name = "vdi", 1035 .instance_size = sizeof(BDRVVdiState), 1036 .bdrv_probe = vdi_probe, 1037 .bdrv_open = vdi_open, 1038 .bdrv_close = vdi_close, 1039 .bdrv_reopen_prepare = vdi_reopen_prepare, 1040 .bdrv_child_perm = bdrv_default_perms, 1041 .bdrv_co_create = vdi_co_create, 1042 .bdrv_co_create_opts = vdi_co_create_opts, 1043 .bdrv_has_zero_init = vdi_has_zero_init, 1044 .bdrv_co_block_status = vdi_co_block_status, 1045 .bdrv_make_empty = vdi_make_empty, 1046 1047 .bdrv_co_preadv = vdi_co_preadv, 1048 #if defined(CONFIG_VDI_WRITE) 1049 .bdrv_co_pwritev = vdi_co_pwritev, 1050 #endif 1051 1052 .bdrv_co_get_info = vdi_co_get_info, 1053 1054 .is_format = true, 1055 .create_opts = &vdi_create_opts, 1056 .bdrv_co_check = vdi_co_check, 1057 }; 1058 1059 static void bdrv_vdi_init(void) 1060 { 1061 logout("\n"); 1062 bdrv_register(&bdrv_vdi); 1063 } 1064 1065 block_init(bdrv_vdi_init); 1066