vdi.c (35448B)
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 vdi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 331 { 332 /* TODO: vdi_get_info would be needed for machine snapshots. 333 vm_state_offset is still missing. */ 334 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 335 logout("\n"); 336 bdi->cluster_size = s->block_size; 337 bdi->vm_state_offset = 0; 338 return 0; 339 } 340 341 static int vdi_make_empty(BlockDriverState *bs) 342 { 343 /* TODO: missing code. */ 344 logout("\n"); 345 /* The return value for missing code must be 0, see block.c. */ 346 return 0; 347 } 348 349 static int vdi_probe(const uint8_t *buf, int buf_size, const char *filename) 350 { 351 const VdiHeader *header = (const VdiHeader *)buf; 352 int ret = 0; 353 354 logout("\n"); 355 356 if (buf_size < sizeof(*header)) { 357 /* Header too small, no VDI. */ 358 } else if (le32_to_cpu(header->signature) == VDI_SIGNATURE) { 359 ret = 100; 360 } 361 362 if (ret == 0) { 363 logout("no vdi image\n"); 364 } else { 365 logout("%s", header->text); 366 } 367 368 return ret; 369 } 370 371 static int vdi_open(BlockDriverState *bs, QDict *options, int flags, 372 Error **errp) 373 { 374 BDRVVdiState *s = bs->opaque; 375 VdiHeader header; 376 size_t bmap_size; 377 int ret; 378 QemuUUID uuid_link, uuid_parent; 379 380 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 381 if (ret < 0) { 382 return ret; 383 } 384 385 logout("\n"); 386 387 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0); 388 if (ret < 0) { 389 goto fail; 390 } 391 392 vdi_header_to_cpu(&header); 393 if (VDI_DEBUG) { 394 vdi_header_print(&header); 395 } 396 397 if (header.disk_size > VDI_DISK_SIZE_MAX) { 398 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64 399 ", max supported is 0x%" PRIx64 ")", 400 header.disk_size, VDI_DISK_SIZE_MAX); 401 ret = -ENOTSUP; 402 goto fail; 403 } 404 405 uuid_link = header.uuid_link; 406 uuid_parent = header.uuid_parent; 407 408 if (header.disk_size % SECTOR_SIZE != 0) { 409 /* 'VBoxManage convertfromraw' can create images with odd disk sizes. 410 We accept them but round the disk size to the next multiple of 411 SECTOR_SIZE. */ 412 logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size); 413 header.disk_size = ROUND_UP(header.disk_size, SECTOR_SIZE); 414 } 415 416 if (header.signature != VDI_SIGNATURE) { 417 error_setg(errp, "Image not in VDI format (bad signature %08" PRIx32 418 ")", header.signature); 419 ret = -EINVAL; 420 goto fail; 421 } else if (header.version != VDI_VERSION_1_1) { 422 error_setg(errp, "unsupported VDI image (version %" PRIu32 ".%" PRIu32 423 ")", header.version >> 16, header.version & 0xffff); 424 ret = -ENOTSUP; 425 goto fail; 426 } else if (header.offset_bmap % SECTOR_SIZE != 0) { 427 /* We only support block maps which start on a sector boundary. */ 428 error_setg(errp, "unsupported VDI image (unaligned block map offset " 429 "0x%" PRIx32 ")", header.offset_bmap); 430 ret = -ENOTSUP; 431 goto fail; 432 } else if (header.offset_data % SECTOR_SIZE != 0) { 433 /* We only support data blocks which start on a sector boundary. */ 434 error_setg(errp, "unsupported VDI image (unaligned data offset 0x%" 435 PRIx32 ")", header.offset_data); 436 ret = -ENOTSUP; 437 goto fail; 438 } else if (header.sector_size != SECTOR_SIZE) { 439 error_setg(errp, "unsupported VDI image (sector size %" PRIu32 440 " is not %u)", header.sector_size, SECTOR_SIZE); 441 ret = -ENOTSUP; 442 goto fail; 443 } else if (header.block_size != DEFAULT_CLUSTER_SIZE) { 444 error_setg(errp, "unsupported VDI image (block size %" PRIu32 445 " is not %" PRIu32 ")", 446 header.block_size, DEFAULT_CLUSTER_SIZE); 447 ret = -ENOTSUP; 448 goto fail; 449 } else if (header.disk_size > 450 (uint64_t)header.blocks_in_image * header.block_size) { 451 error_setg(errp, "unsupported VDI image (disk size %" PRIu64 ", " 452 "image bitmap has room for %" PRIu64 ")", 453 header.disk_size, 454 (uint64_t)header.blocks_in_image * header.block_size); 455 ret = -ENOTSUP; 456 goto fail; 457 } else if (!qemu_uuid_is_null(&uuid_link)) { 458 error_setg(errp, "unsupported VDI image (non-NULL link UUID)"); 459 ret = -ENOTSUP; 460 goto fail; 461 } else if (!qemu_uuid_is_null(&uuid_parent)) { 462 error_setg(errp, "unsupported VDI image (non-NULL parent UUID)"); 463 ret = -ENOTSUP; 464 goto fail; 465 } else if (header.blocks_in_image > VDI_BLOCKS_IN_IMAGE_MAX) { 466 error_setg(errp, "unsupported VDI image " 467 "(too many blocks %u, max is %u)", 468 header.blocks_in_image, VDI_BLOCKS_IN_IMAGE_MAX); 469 ret = -ENOTSUP; 470 goto fail; 471 } 472 473 bs->total_sectors = header.disk_size / SECTOR_SIZE; 474 475 s->block_size = header.block_size; 476 s->bmap_sector = header.offset_bmap / SECTOR_SIZE; 477 s->header = header; 478 479 bmap_size = header.blocks_in_image * sizeof(uint32_t); 480 bmap_size = DIV_ROUND_UP(bmap_size, SECTOR_SIZE); 481 s->bmap = qemu_try_blockalign(bs->file->bs, bmap_size * SECTOR_SIZE); 482 if (s->bmap == NULL) { 483 ret = -ENOMEM; 484 goto fail; 485 } 486 487 ret = bdrv_pread(bs->file, header.offset_bmap, bmap_size * SECTOR_SIZE, 488 s->bmap, 0); 489 if (ret < 0) { 490 goto fail_free_bmap; 491 } 492 493 /* Disable migration when vdi images are used */ 494 error_setg(&s->migration_blocker, "The vdi format used by node '%s' " 495 "does not support live migration", 496 bdrv_get_device_or_node_name(bs)); 497 ret = migrate_add_blocker(s->migration_blocker, errp); 498 if (ret < 0) { 499 error_free(s->migration_blocker); 500 goto fail_free_bmap; 501 } 502 503 qemu_co_rwlock_init(&s->bmap_lock); 504 505 return 0; 506 507 fail_free_bmap: 508 qemu_vfree(s->bmap); 509 510 fail: 511 return ret; 512 } 513 514 static int vdi_reopen_prepare(BDRVReopenState *state, 515 BlockReopenQueue *queue, Error **errp) 516 { 517 return 0; 518 } 519 520 static int coroutine_fn vdi_co_block_status(BlockDriverState *bs, 521 bool want_zero, 522 int64_t offset, int64_t bytes, 523 int64_t *pnum, int64_t *map, 524 BlockDriverState **file) 525 { 526 BDRVVdiState *s = (BDRVVdiState *)bs->opaque; 527 size_t bmap_index = offset / s->block_size; 528 size_t index_in_block = offset % s->block_size; 529 uint32_t bmap_entry = le32_to_cpu(s->bmap[bmap_index]); 530 int result; 531 532 logout("%p, %" PRId64 ", %" PRId64 ", %p\n", bs, offset, bytes, pnum); 533 *pnum = MIN(s->block_size - index_in_block, bytes); 534 result = VDI_IS_ALLOCATED(bmap_entry); 535 if (!result) { 536 return BDRV_BLOCK_ZERO; 537 } 538 539 *map = s->header.offset_data + (uint64_t)bmap_entry * s->block_size + 540 index_in_block; 541 *file = bs->file->bs; 542 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | 543 (s->header.image_type == VDI_TYPE_STATIC ? BDRV_BLOCK_RECURSE : 0); 544 } 545 546 static int coroutine_fn 547 vdi_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 548 QEMUIOVector *qiov, BdrvRequestFlags flags) 549 { 550 BDRVVdiState *s = bs->opaque; 551 QEMUIOVector local_qiov; 552 uint32_t bmap_entry; 553 uint32_t block_index; 554 uint32_t offset_in_block; 555 uint32_t n_bytes; 556 uint64_t bytes_done = 0; 557 int ret = 0; 558 559 logout("\n"); 560 561 qemu_iovec_init(&local_qiov, qiov->niov); 562 563 while (ret >= 0 && bytes > 0) { 564 block_index = offset / s->block_size; 565 offset_in_block = offset % s->block_size; 566 n_bytes = MIN(bytes, s->block_size - offset_in_block); 567 568 logout("will read %u bytes starting at offset %" PRIu64 "\n", 569 n_bytes, offset); 570 571 /* prepare next AIO request */ 572 qemu_co_rwlock_rdlock(&s->bmap_lock); 573 bmap_entry = le32_to_cpu(s->bmap[block_index]); 574 qemu_co_rwlock_unlock(&s->bmap_lock); 575 if (!VDI_IS_ALLOCATED(bmap_entry)) { 576 /* Block not allocated, return zeros, no need to wait. */ 577 qemu_iovec_memset(qiov, bytes_done, 0, n_bytes); 578 ret = 0; 579 } else { 580 uint64_t data_offset = s->header.offset_data + 581 (uint64_t)bmap_entry * s->block_size + 582 offset_in_block; 583 584 qemu_iovec_reset(&local_qiov); 585 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); 586 587 ret = bdrv_co_preadv(bs->file, data_offset, n_bytes, 588 &local_qiov, 0); 589 } 590 logout("%u bytes read\n", n_bytes); 591 592 bytes -= n_bytes; 593 offset += n_bytes; 594 bytes_done += n_bytes; 595 } 596 597 qemu_iovec_destroy(&local_qiov); 598 599 return ret; 600 } 601 602 static int coroutine_fn 603 vdi_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, 604 QEMUIOVector *qiov, BdrvRequestFlags flags) 605 { 606 BDRVVdiState *s = bs->opaque; 607 QEMUIOVector local_qiov; 608 uint32_t bmap_entry; 609 uint32_t block_index; 610 uint32_t offset_in_block; 611 uint32_t n_bytes; 612 uint64_t data_offset; 613 uint32_t bmap_first = VDI_UNALLOCATED; 614 uint32_t bmap_last = VDI_UNALLOCATED; 615 uint8_t *block = NULL; 616 uint64_t bytes_done = 0; 617 int ret = 0; 618 619 logout("\n"); 620 621 qemu_iovec_init(&local_qiov, qiov->niov); 622 623 while (ret >= 0 && bytes > 0) { 624 block_index = offset / s->block_size; 625 offset_in_block = offset % s->block_size; 626 n_bytes = MIN(bytes, s->block_size - offset_in_block); 627 628 logout("will write %u bytes starting at offset %" PRIu64 "\n", 629 n_bytes, offset); 630 631 /* prepare next AIO request */ 632 qemu_co_rwlock_rdlock(&s->bmap_lock); 633 bmap_entry = le32_to_cpu(s->bmap[block_index]); 634 if (!VDI_IS_ALLOCATED(bmap_entry)) { 635 /* Allocate new block and write to it. */ 636 uint64_t data_offset; 637 qemu_co_rwlock_upgrade(&s->bmap_lock); 638 bmap_entry = le32_to_cpu(s->bmap[block_index]); 639 if (VDI_IS_ALLOCATED(bmap_entry)) { 640 /* A concurrent allocation did the work for us. */ 641 qemu_co_rwlock_downgrade(&s->bmap_lock); 642 goto nonallocating_write; 643 } 644 645 bmap_entry = s->header.blocks_allocated; 646 s->bmap[block_index] = cpu_to_le32(bmap_entry); 647 s->header.blocks_allocated++; 648 data_offset = s->header.offset_data + 649 (uint64_t)bmap_entry * s->block_size; 650 if (block == NULL) { 651 block = g_malloc(s->block_size); 652 bmap_first = block_index; 653 } 654 bmap_last = block_index; 655 /* Copy data to be written to new block and zero unused parts. */ 656 memset(block, 0, offset_in_block); 657 qemu_iovec_to_buf(qiov, bytes_done, block + offset_in_block, 658 n_bytes); 659 memset(block + offset_in_block + n_bytes, 0, 660 s->block_size - n_bytes - offset_in_block); 661 662 /* Write the new block under CoRwLock write-side protection, 663 * so this full-cluster write does not overlap a partial write 664 * of the same cluster, issued from the "else" branch. 665 */ 666 ret = bdrv_co_pwrite(bs->file, data_offset, s->block_size, block, 667 0); 668 qemu_co_rwlock_unlock(&s->bmap_lock); 669 } else { 670 nonallocating_write: 671 data_offset = s->header.offset_data + 672 (uint64_t)bmap_entry * s->block_size + 673 offset_in_block; 674 qemu_co_rwlock_unlock(&s->bmap_lock); 675 676 qemu_iovec_reset(&local_qiov); 677 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes); 678 679 ret = bdrv_co_pwritev(bs->file, data_offset, n_bytes, 680 &local_qiov, 0); 681 } 682 683 bytes -= n_bytes; 684 offset += n_bytes; 685 bytes_done += n_bytes; 686 687 logout("%u bytes written\n", n_bytes); 688 } 689 690 qemu_iovec_destroy(&local_qiov); 691 692 logout("finished data write\n"); 693 if (ret < 0) { 694 g_free(block); 695 return ret; 696 } 697 698 if (block) { 699 /* One or more new blocks were allocated. */ 700 VdiHeader *header; 701 uint8_t *base; 702 uint64_t offset; 703 uint32_t n_sectors; 704 705 g_free(block); 706 header = g_malloc(sizeof(*header)); 707 708 logout("now writing modified header\n"); 709 assert(VDI_IS_ALLOCATED(bmap_first)); 710 *header = s->header; 711 vdi_header_to_le(header); 712 ret = bdrv_co_pwrite(bs->file, 0, sizeof(*header), header, 0); 713 g_free(header); 714 715 if (ret < 0) { 716 return ret; 717 } 718 719 logout("now writing modified block map entry %u...%u\n", 720 bmap_first, bmap_last); 721 /* Write modified sectors from block map. */ 722 bmap_first /= (SECTOR_SIZE / sizeof(uint32_t)); 723 bmap_last /= (SECTOR_SIZE / sizeof(uint32_t)); 724 n_sectors = bmap_last - bmap_first + 1; 725 offset = s->bmap_sector + bmap_first; 726 base = ((uint8_t *)&s->bmap[0]) + bmap_first * SECTOR_SIZE; 727 logout("will write %u block map sectors starting from entry %u\n", 728 n_sectors, bmap_first); 729 ret = bdrv_co_pwrite(bs->file, offset * SECTOR_SIZE, 730 n_sectors * SECTOR_SIZE, base, 0); 731 } 732 733 return ret; 734 } 735 736 static int coroutine_fn vdi_co_do_create(BlockdevCreateOptions *create_options, 737 size_t block_size, Error **errp) 738 { 739 BlockdevCreateOptionsVdi *vdi_opts; 740 int ret = 0; 741 uint64_t bytes = 0; 742 uint32_t blocks; 743 uint32_t image_type; 744 VdiHeader header; 745 size_t i; 746 size_t bmap_size; 747 int64_t offset = 0; 748 BlockDriverState *bs_file = NULL; 749 BlockBackend *blk = NULL; 750 uint32_t *bmap = NULL; 751 QemuUUID uuid; 752 753 assert(create_options->driver == BLOCKDEV_DRIVER_VDI); 754 vdi_opts = &create_options->u.vdi; 755 756 logout("\n"); 757 758 /* Validate options and set default values */ 759 bytes = vdi_opts->size; 760 761 if (!vdi_opts->has_preallocation) { 762 vdi_opts->preallocation = PREALLOC_MODE_OFF; 763 } 764 switch (vdi_opts->preallocation) { 765 case PREALLOC_MODE_OFF: 766 image_type = VDI_TYPE_DYNAMIC; 767 break; 768 case PREALLOC_MODE_METADATA: 769 image_type = VDI_TYPE_STATIC; 770 break; 771 default: 772 error_setg(errp, "Preallocation mode not supported for vdi"); 773 return -EINVAL; 774 } 775 776 #ifndef CONFIG_VDI_STATIC_IMAGE 777 if (image_type == VDI_TYPE_STATIC) { 778 ret = -ENOTSUP; 779 error_setg(errp, "Statically allocated images cannot be created in " 780 "this build"); 781 goto exit; 782 } 783 #endif 784 #ifndef CONFIG_VDI_BLOCK_SIZE 785 if (block_size != DEFAULT_CLUSTER_SIZE) { 786 ret = -ENOTSUP; 787 error_setg(errp, 788 "A non-default cluster size is not supported in this build"); 789 goto exit; 790 } 791 #endif 792 793 if (bytes > VDI_DISK_SIZE_MAX) { 794 ret = -ENOTSUP; 795 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64 796 ", max supported is 0x%" PRIx64 ")", 797 bytes, VDI_DISK_SIZE_MAX); 798 goto exit; 799 } 800 801 /* Create BlockBackend to write to the image */ 802 bs_file = bdrv_open_blockdev_ref(vdi_opts->file, errp); 803 if (!bs_file) { 804 ret = -EIO; 805 goto exit; 806 } 807 808 blk = blk_new_with_bs(bs_file, BLK_PERM_WRITE | BLK_PERM_RESIZE, 809 BLK_PERM_ALL, errp); 810 if (!blk) { 811 ret = -EPERM; 812 goto exit; 813 } 814 815 blk_set_allow_write_beyond_eof(blk, true); 816 817 /* We need enough blocks to store the given disk size, 818 so always round up. */ 819 blocks = DIV_ROUND_UP(bytes, block_size); 820 821 bmap_size = blocks * sizeof(uint32_t); 822 bmap_size = ROUND_UP(bmap_size, SECTOR_SIZE); 823 824 memset(&header, 0, sizeof(header)); 825 pstrcpy(header.text, sizeof(header.text), VDI_TEXT); 826 header.signature = VDI_SIGNATURE; 827 header.version = VDI_VERSION_1_1; 828 header.header_size = 0x180; 829 header.image_type = image_type; 830 header.offset_bmap = 0x200; 831 header.offset_data = 0x200 + bmap_size; 832 header.sector_size = SECTOR_SIZE; 833 header.disk_size = bytes; 834 header.block_size = block_size; 835 header.blocks_in_image = blocks; 836 if (image_type == VDI_TYPE_STATIC) { 837 header.blocks_allocated = blocks; 838 } 839 qemu_uuid_generate(&uuid); 840 header.uuid_image = uuid; 841 qemu_uuid_generate(&uuid); 842 header.uuid_last_snap = uuid; 843 /* There is no need to set header.uuid_link or header.uuid_parent here. */ 844 if (VDI_DEBUG) { 845 vdi_header_print(&header); 846 } 847 vdi_header_to_le(&header); 848 ret = blk_co_pwrite(blk, offset, sizeof(header), &header, 0); 849 if (ret < 0) { 850 error_setg(errp, "Error writing header"); 851 goto exit; 852 } 853 offset += sizeof(header); 854 855 if (bmap_size > 0) { 856 bmap = g_try_malloc0(bmap_size); 857 if (bmap == NULL) { 858 ret = -ENOMEM; 859 error_setg(errp, "Could not allocate bmap"); 860 goto exit; 861 } 862 for (i = 0; i < blocks; i++) { 863 if (image_type == VDI_TYPE_STATIC) { 864 bmap[i] = i; 865 } else { 866 bmap[i] = VDI_UNALLOCATED; 867 } 868 } 869 ret = blk_co_pwrite(blk, offset, bmap_size, bmap, 0); 870 if (ret < 0) { 871 error_setg(errp, "Error writing bmap"); 872 goto exit; 873 } 874 offset += bmap_size; 875 } 876 877 if (image_type == VDI_TYPE_STATIC) { 878 ret = blk_co_truncate(blk, offset + blocks * block_size, false, 879 PREALLOC_MODE_OFF, 0, errp); 880 if (ret < 0) { 881 error_prepend(errp, "Failed to statically allocate file"); 882 goto exit; 883 } 884 } 885 886 ret = 0; 887 exit: 888 blk_unref(blk); 889 bdrv_unref(bs_file); 890 g_free(bmap); 891 return ret; 892 } 893 894 static int coroutine_fn vdi_co_create(BlockdevCreateOptions *create_options, 895 Error **errp) 896 { 897 return vdi_co_do_create(create_options, DEFAULT_CLUSTER_SIZE, errp); 898 } 899 900 static int coroutine_fn vdi_co_create_opts(BlockDriver *drv, 901 const char *filename, 902 QemuOpts *opts, 903 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_create_file(filename, opts, errp); 938 if (ret < 0) { 939 goto done; 940 } 941 942 bs_file = bdrv_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_get_info = vdi_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);