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
vdi_header_to_cpu(VdiHeader * header)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
vdi_header_to_le(VdiHeader * header)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
vdi_header_print(VdiHeader * header)240 static void vdi_header_print(VdiHeader *header)
241 {
242 char uuidstr[UUID_STR_LEN];
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
vdi_co_check(BlockDriverState * bs,BdrvCheckResult * res,BdrvCheckMode fix)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
vdi_co_get_info(BlockDriverState * bs,BlockDriverInfo * bdi)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
vdi_make_empty(BlockDriverState * bs)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
vdi_probe(const uint8_t * buf,int buf_size,const char * filename)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
vdi_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)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 GRAPH_RDLOCK_GUARD_MAINLOOP();
387
388 logout("\n");
389
390 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0);
391 if (ret < 0) {
392 goto fail;
393 }
394
395 vdi_header_to_cpu(&header);
396 if (VDI_DEBUG) {
397 vdi_header_print(&header);
398 }
399
400 if (header.disk_size > VDI_DISK_SIZE_MAX) {
401 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64
402 ", max supported is 0x%" PRIx64 ")",
403 header.disk_size, VDI_DISK_SIZE_MAX);
404 ret = -ENOTSUP;
405 goto fail;
406 }
407
408 uuid_link = header.uuid_link;
409 uuid_parent = header.uuid_parent;
410
411 if (header.disk_size % SECTOR_SIZE != 0) {
412 /* 'VBoxManage convertfromraw' can create images with odd disk sizes.
413 We accept them but round the disk size to the next multiple of
414 SECTOR_SIZE. */
415 logout("odd disk size %" PRIu64 " B, round up\n", header.disk_size);
416 header.disk_size = ROUND_UP(header.disk_size, SECTOR_SIZE);
417 }
418
419 if (header.signature != VDI_SIGNATURE) {
420 error_setg(errp, "Image not in VDI format (bad signature %08" PRIx32
421 ")", header.signature);
422 ret = -EINVAL;
423 goto fail;
424 } else if (header.version != VDI_VERSION_1_1) {
425 error_setg(errp, "unsupported VDI image (version %" PRIu32 ".%" PRIu32
426 ")", header.version >> 16, header.version & 0xffff);
427 ret = -ENOTSUP;
428 goto fail;
429 } else if (header.offset_bmap % SECTOR_SIZE != 0) {
430 /* We only support block maps which start on a sector boundary. */
431 error_setg(errp, "unsupported VDI image (unaligned block map offset "
432 "0x%" PRIx32 ")", header.offset_bmap);
433 ret = -ENOTSUP;
434 goto fail;
435 } else if (header.offset_data % SECTOR_SIZE != 0) {
436 /* We only support data blocks which start on a sector boundary. */
437 error_setg(errp, "unsupported VDI image (unaligned data offset 0x%"
438 PRIx32 ")", header.offset_data);
439 ret = -ENOTSUP;
440 goto fail;
441 } else if (header.sector_size != SECTOR_SIZE) {
442 error_setg(errp, "unsupported VDI image (sector size %" PRIu32
443 " is not %u)", header.sector_size, SECTOR_SIZE);
444 ret = -ENOTSUP;
445 goto fail;
446 } else if (header.block_size != DEFAULT_CLUSTER_SIZE) {
447 error_setg(errp, "unsupported VDI image (block size %" PRIu32
448 " is not %" PRIu32 ")",
449 header.block_size, DEFAULT_CLUSTER_SIZE);
450 ret = -ENOTSUP;
451 goto fail;
452 } else if (header.disk_size >
453 (uint64_t)header.blocks_in_image * header.block_size) {
454 error_setg(errp, "unsupported VDI image (disk size %" PRIu64 ", "
455 "image bitmap has room for %" PRIu64 ")",
456 header.disk_size,
457 (uint64_t)header.blocks_in_image * header.block_size);
458 ret = -ENOTSUP;
459 goto fail;
460 } else if (!qemu_uuid_is_null(&uuid_link)) {
461 error_setg(errp, "unsupported VDI image (non-NULL link UUID)");
462 ret = -ENOTSUP;
463 goto fail;
464 } else if (!qemu_uuid_is_null(&uuid_parent)) {
465 error_setg(errp, "unsupported VDI image (non-NULL parent UUID)");
466 ret = -ENOTSUP;
467 goto fail;
468 } else if (header.blocks_in_image > VDI_BLOCKS_IN_IMAGE_MAX) {
469 error_setg(errp, "unsupported VDI image "
470 "(too many blocks %u, max is %u)",
471 header.blocks_in_image, VDI_BLOCKS_IN_IMAGE_MAX);
472 ret = -ENOTSUP;
473 goto fail;
474 }
475
476 bs->total_sectors = header.disk_size / SECTOR_SIZE;
477
478 s->block_size = header.block_size;
479 s->bmap_sector = header.offset_bmap / SECTOR_SIZE;
480 s->header = header;
481
482 bmap_size = header.blocks_in_image * sizeof(uint32_t);
483 bmap_size = DIV_ROUND_UP(bmap_size, SECTOR_SIZE);
484 s->bmap = qemu_try_blockalign(bs->file->bs, bmap_size * SECTOR_SIZE);
485 if (s->bmap == NULL) {
486 ret = -ENOMEM;
487 goto fail;
488 }
489
490 ret = bdrv_pread(bs->file, header.offset_bmap, bmap_size * SECTOR_SIZE,
491 s->bmap, 0);
492 if (ret < 0) {
493 goto fail_free_bmap;
494 }
495
496 /* Disable migration when vdi images are used */
497 error_setg(&s->migration_blocker, "The vdi format used by node '%s' "
498 "does not support live migration",
499 bdrv_get_device_or_node_name(bs));
500
501 ret = migrate_add_blocker_normal(&s->migration_blocker, errp);
502 if (ret < 0) {
503 goto fail_free_bmap;
504 }
505
506 qemu_co_rwlock_init(&s->bmap_lock);
507
508 return 0;
509
510 fail_free_bmap:
511 qemu_vfree(s->bmap);
512
513 fail:
514 return ret;
515 }
516
vdi_reopen_prepare(BDRVReopenState * state,BlockReopenQueue * queue,Error ** errp)517 static int vdi_reopen_prepare(BDRVReopenState *state,
518 BlockReopenQueue *queue, Error **errp)
519 {
520 return 0;
521 }
522
523 static int coroutine_fn GRAPH_RDLOCK
vdi_co_block_status(BlockDriverState * bs,bool want_zero,int64_t offset,int64_t bytes,int64_t * pnum,int64_t * map,BlockDriverState ** file)524 vdi_co_block_status(BlockDriverState *bs, bool want_zero, int64_t offset,
525 int64_t bytes, int64_t *pnum, int64_t *map,
526 BlockDriverState **file)
527 {
528 BDRVVdiState *s = (BDRVVdiState *)bs->opaque;
529 size_t bmap_index = offset / s->block_size;
530 size_t index_in_block = offset % s->block_size;
531 uint32_t bmap_entry = le32_to_cpu(s->bmap[bmap_index]);
532 int result;
533
534 logout("%p, %" PRId64 ", %" PRId64 ", %p\n", bs, offset, bytes, pnum);
535 *pnum = MIN(s->block_size - index_in_block, bytes);
536 result = VDI_IS_ALLOCATED(bmap_entry);
537 if (!result) {
538 return BDRV_BLOCK_ZERO;
539 }
540
541 *map = s->header.offset_data + (uint64_t)bmap_entry * s->block_size +
542 index_in_block;
543 *file = bs->file->bs;
544 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID |
545 (s->header.image_type == VDI_TYPE_STATIC ? BDRV_BLOCK_RECURSE : 0);
546 }
547
548 static int coroutine_fn GRAPH_RDLOCK
vdi_co_preadv(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)549 vdi_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
550 QEMUIOVector *qiov, BdrvRequestFlags flags)
551 {
552 BDRVVdiState *s = bs->opaque;
553 QEMUIOVector local_qiov;
554 uint32_t bmap_entry;
555 uint32_t block_index;
556 uint32_t offset_in_block;
557 uint32_t n_bytes;
558 uint64_t bytes_done = 0;
559 int ret = 0;
560
561 logout("\n");
562
563 qemu_iovec_init(&local_qiov, qiov->niov);
564
565 while (ret >= 0 && bytes > 0) {
566 block_index = offset / s->block_size;
567 offset_in_block = offset % s->block_size;
568 n_bytes = MIN(bytes, s->block_size - offset_in_block);
569
570 logout("will read %u bytes starting at offset %" PRIu64 "\n",
571 n_bytes, offset);
572
573 /* prepare next AIO request */
574 qemu_co_rwlock_rdlock(&s->bmap_lock);
575 bmap_entry = le32_to_cpu(s->bmap[block_index]);
576 qemu_co_rwlock_unlock(&s->bmap_lock);
577 if (!VDI_IS_ALLOCATED(bmap_entry)) {
578 /* Block not allocated, return zeros, no need to wait. */
579 qemu_iovec_memset(qiov, bytes_done, 0, n_bytes);
580 ret = 0;
581 } else {
582 uint64_t data_offset = s->header.offset_data +
583 (uint64_t)bmap_entry * s->block_size +
584 offset_in_block;
585
586 qemu_iovec_reset(&local_qiov);
587 qemu_iovec_concat(&local_qiov, qiov, bytes_done, n_bytes);
588
589 ret = bdrv_co_preadv(bs->file, data_offset, n_bytes,
590 &local_qiov, 0);
591 }
592 logout("%u bytes read\n", n_bytes);
593
594 bytes -= n_bytes;
595 offset += n_bytes;
596 bytes_done += n_bytes;
597 }
598
599 qemu_iovec_destroy(&local_qiov);
600
601 return ret;
602 }
603
604 static int coroutine_fn GRAPH_RDLOCK
vdi_co_pwritev(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)605 vdi_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
606 QEMUIOVector *qiov, BdrvRequestFlags flags)
607 {
608 BDRVVdiState *s = bs->opaque;
609 QEMUIOVector local_qiov;
610 uint32_t bmap_entry;
611 uint32_t block_index;
612 uint32_t offset_in_block;
613 uint32_t n_bytes;
614 uint64_t data_offset;
615 uint32_t bmap_first = VDI_UNALLOCATED;
616 uint32_t bmap_last = VDI_UNALLOCATED;
617 uint8_t *block = NULL;
618 uint64_t bytes_done = 0;
619 int ret = 0;
620
621 logout("\n");
622
623 qemu_iovec_init(&local_qiov, qiov->niov);
624
625 while (ret >= 0 && bytes > 0) {
626 block_index = offset / s->block_size;
627 offset_in_block = offset % s->block_size;
628 n_bytes = MIN(bytes, s->block_size - offset_in_block);
629
630 logout("will write %u bytes starting at offset %" PRIu64 "\n",
631 n_bytes, offset);
632
633 /* prepare next AIO request */
634 qemu_co_rwlock_rdlock(&s->bmap_lock);
635 bmap_entry = le32_to_cpu(s->bmap[block_index]);
636 if (!VDI_IS_ALLOCATED(bmap_entry)) {
637 /* Allocate new block and write to it. */
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 bmap_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 bmap_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, bmap_offset * SECTOR_SIZE,
731 n_sectors * SECTOR_SIZE, base, 0);
732 }
733
734 return ret;
735 }
736
737 static int coroutine_fn GRAPH_UNLOCKED
vdi_co_do_create(BlockdevCreateOptions * create_options,size_t block_size,Error ** errp)738 vdi_co_do_create(BlockdevCreateOptions *create_options, size_t block_size,
739 Error **errp)
740 {
741 ERRP_GUARD();
742 BlockdevCreateOptionsVdi *vdi_opts;
743 int ret = 0;
744 uint64_t bytes = 0;
745 uint32_t blocks;
746 uint32_t image_type;
747 VdiHeader header;
748 size_t i;
749 size_t bmap_size;
750 int64_t offset = 0;
751 BlockDriverState *bs_file = NULL;
752 BlockBackend *blk = NULL;
753 uint32_t *bmap = NULL;
754 QemuUUID uuid;
755
756 assert(create_options->driver == BLOCKDEV_DRIVER_VDI);
757 vdi_opts = &create_options->u.vdi;
758
759 logout("\n");
760
761 /* Validate options and set default values */
762 bytes = vdi_opts->size;
763
764 if (!vdi_opts->has_preallocation) {
765 vdi_opts->preallocation = PREALLOC_MODE_OFF;
766 }
767 switch (vdi_opts->preallocation) {
768 case PREALLOC_MODE_OFF:
769 image_type = VDI_TYPE_DYNAMIC;
770 break;
771 case PREALLOC_MODE_METADATA:
772 image_type = VDI_TYPE_STATIC;
773 break;
774 default:
775 error_setg(errp, "Preallocation mode not supported for vdi");
776 return -EINVAL;
777 }
778
779 #ifndef CONFIG_VDI_STATIC_IMAGE
780 if (image_type == VDI_TYPE_STATIC) {
781 ret = -ENOTSUP;
782 error_setg(errp, "Statically allocated images cannot be created in "
783 "this build");
784 goto exit;
785 }
786 #endif
787 #ifndef CONFIG_VDI_BLOCK_SIZE
788 if (block_size != DEFAULT_CLUSTER_SIZE) {
789 ret = -ENOTSUP;
790 error_setg(errp,
791 "A non-default cluster size is not supported in this build");
792 goto exit;
793 }
794 #endif
795
796 if (bytes > VDI_DISK_SIZE_MAX) {
797 ret = -ENOTSUP;
798 error_setg(errp, "Unsupported VDI image size (size is 0x%" PRIx64
799 ", max supported is 0x%" PRIx64 ")",
800 bytes, VDI_DISK_SIZE_MAX);
801 goto exit;
802 }
803
804 /* Create BlockBackend to write to the image */
805 bs_file = bdrv_co_open_blockdev_ref(vdi_opts->file, errp);
806 if (!bs_file) {
807 ret = -EIO;
808 goto exit;
809 }
810
811 blk = blk_co_new_with_bs(bs_file, BLK_PERM_WRITE | BLK_PERM_RESIZE,
812 BLK_PERM_ALL, errp);
813 if (!blk) {
814 ret = -EPERM;
815 goto exit;
816 }
817
818 blk_set_allow_write_beyond_eof(blk, true);
819
820 /* We need enough blocks to store the given disk size,
821 so always round up. */
822 blocks = DIV_ROUND_UP(bytes, block_size);
823
824 bmap_size = blocks * sizeof(uint32_t);
825 bmap_size = ROUND_UP(bmap_size, SECTOR_SIZE);
826
827 memset(&header, 0, sizeof(header));
828 pstrcpy(header.text, sizeof(header.text), VDI_TEXT);
829 header.signature = VDI_SIGNATURE;
830 header.version = VDI_VERSION_1_1;
831 header.header_size = 0x180;
832 header.image_type = image_type;
833 header.offset_bmap = 0x200;
834 header.offset_data = 0x200 + bmap_size;
835 header.sector_size = SECTOR_SIZE;
836 header.disk_size = bytes;
837 header.block_size = block_size;
838 header.blocks_in_image = blocks;
839 if (image_type == VDI_TYPE_STATIC) {
840 header.blocks_allocated = blocks;
841 }
842 qemu_uuid_generate(&uuid);
843 header.uuid_image = uuid;
844 qemu_uuid_generate(&uuid);
845 header.uuid_last_snap = uuid;
846 /* There is no need to set header.uuid_link or header.uuid_parent here. */
847 if (VDI_DEBUG) {
848 vdi_header_print(&header);
849 }
850 vdi_header_to_le(&header);
851 ret = blk_co_pwrite(blk, offset, sizeof(header), &header, 0);
852 if (ret < 0) {
853 error_setg(errp, "Error writing header");
854 goto exit;
855 }
856 offset += sizeof(header);
857
858 if (bmap_size > 0) {
859 bmap = g_try_malloc0(bmap_size);
860 if (bmap == NULL) {
861 ret = -ENOMEM;
862 error_setg(errp, "Could not allocate bmap");
863 goto exit;
864 }
865 for (i = 0; i < blocks; i++) {
866 if (image_type == VDI_TYPE_STATIC) {
867 bmap[i] = i;
868 } else {
869 bmap[i] = VDI_UNALLOCATED;
870 }
871 }
872 ret = blk_co_pwrite(blk, offset, bmap_size, bmap, 0);
873 if (ret < 0) {
874 error_setg(errp, "Error writing bmap");
875 goto exit;
876 }
877 offset += bmap_size;
878 }
879
880 if (image_type == VDI_TYPE_STATIC) {
881 ret = blk_co_truncate(blk, offset + blocks * block_size, false,
882 PREALLOC_MODE_OFF, 0, errp);
883 if (ret < 0) {
884 error_prepend(errp, "Failed to statically allocate file");
885 goto exit;
886 }
887 }
888
889 ret = 0;
890 exit:
891 blk_co_unref(blk);
892 bdrv_co_unref(bs_file);
893 g_free(bmap);
894 return ret;
895 }
896
897 static int coroutine_fn GRAPH_UNLOCKED
vdi_co_create(BlockdevCreateOptions * create_options,Error ** errp)898 vdi_co_create(BlockdevCreateOptions *create_options, Error **errp)
899 {
900 return vdi_co_do_create(create_options, DEFAULT_CLUSTER_SIZE, errp);
901 }
902
903 static int coroutine_fn GRAPH_UNLOCKED
vdi_co_create_opts(BlockDriver * drv,const char * filename,QemuOpts * opts,Error ** errp)904 vdi_co_create_opts(BlockDriver *drv, const char *filename,
905 QemuOpts *opts, Error **errp)
906 {
907 QDict *qdict = NULL;
908 BlockdevCreateOptions *create_options = NULL;
909 BlockDriverState *bs_file = NULL;
910 uint64_t block_size = DEFAULT_CLUSTER_SIZE;
911 bool is_static = false;
912 Visitor *v;
913 int ret;
914
915 /* Parse options and convert legacy syntax.
916 *
917 * Since CONFIG_VDI_BLOCK_SIZE is disabled by default,
918 * cluster-size is not part of the QAPI schema; therefore we have
919 * to parse it before creating the QAPI object. */
920 #if defined(CONFIG_VDI_BLOCK_SIZE)
921 block_size = qemu_opt_get_size_del(opts,
922 BLOCK_OPT_CLUSTER_SIZE,
923 DEFAULT_CLUSTER_SIZE);
924 if (block_size < BDRV_SECTOR_SIZE || block_size > UINT32_MAX ||
925 !is_power_of_2(block_size))
926 {
927 error_setg(errp, "Invalid cluster size");
928 ret = -EINVAL;
929 goto done;
930 }
931 #endif
932 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_STATIC, false)) {
933 is_static = true;
934 }
935
936 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &vdi_create_opts, true);
937
938 /* Create and open the file (protocol layer) */
939 ret = bdrv_co_create_file(filename, opts, errp);
940 if (ret < 0) {
941 goto done;
942 }
943
944 bs_file = bdrv_co_open(filename, NULL, NULL,
945 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
946 if (!bs_file) {
947 ret = -EIO;
948 goto done;
949 }
950
951 qdict_put_str(qdict, "driver", "vdi");
952 qdict_put_str(qdict, "file", bs_file->node_name);
953 if (is_static) {
954 qdict_put_str(qdict, "preallocation", "metadata");
955 }
956
957 /* Get the QAPI object */
958 v = qobject_input_visitor_new_flat_confused(qdict, errp);
959 if (!v) {
960 ret = -EINVAL;
961 goto done;
962 }
963 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
964 visit_free(v);
965 if (!create_options) {
966 ret = -EINVAL;
967 goto done;
968 }
969
970 /* Silently round up size */
971 assert(create_options->driver == BLOCKDEV_DRIVER_VDI);
972 create_options->u.vdi.size = ROUND_UP(create_options->u.vdi.size,
973 BDRV_SECTOR_SIZE);
974
975 /* Create the vdi image (format layer) */
976 ret = vdi_co_do_create(create_options, block_size, errp);
977 done:
978 qobject_unref(qdict);
979 qapi_free_BlockdevCreateOptions(create_options);
980 bdrv_co_unref(bs_file);
981 return ret;
982 }
983
vdi_close(BlockDriverState * bs)984 static void vdi_close(BlockDriverState *bs)
985 {
986 BDRVVdiState *s = bs->opaque;
987
988 qemu_vfree(s->bmap);
989
990 migrate_del_blocker(&s->migration_blocker);
991 }
992
vdi_has_zero_init(BlockDriverState * bs)993 static int GRAPH_RDLOCK vdi_has_zero_init(BlockDriverState *bs)
994 {
995 BDRVVdiState *s = bs->opaque;
996
997 if (s->header.image_type == VDI_TYPE_STATIC) {
998 return bdrv_has_zero_init(bs->file->bs);
999 } else {
1000 return 1;
1001 }
1002 }
1003
1004 static QemuOptsList vdi_create_opts = {
1005 .name = "vdi-create-opts",
1006 .head = QTAILQ_HEAD_INITIALIZER(vdi_create_opts.head),
1007 .desc = {
1008 {
1009 .name = BLOCK_OPT_SIZE,
1010 .type = QEMU_OPT_SIZE,
1011 .help = "Virtual disk size"
1012 },
1013 #if defined(CONFIG_VDI_BLOCK_SIZE)
1014 {
1015 .name = BLOCK_OPT_CLUSTER_SIZE,
1016 .type = QEMU_OPT_SIZE,
1017 .help = "VDI cluster (block) size",
1018 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
1019 },
1020 #endif
1021 #if defined(CONFIG_VDI_STATIC_IMAGE)
1022 {
1023 .name = BLOCK_OPT_STATIC,
1024 .type = QEMU_OPT_BOOL,
1025 .help = "VDI static (pre-allocated) image",
1026 .def_value_str = "off"
1027 },
1028 #endif
1029 /* TODO: An additional option to set UUID values might be useful. */
1030 { /* end of list */ }
1031 }
1032 };
1033
1034 static BlockDriver bdrv_vdi = {
1035 .format_name = "vdi",
1036 .instance_size = sizeof(BDRVVdiState),
1037 .bdrv_probe = vdi_probe,
1038 .bdrv_open = vdi_open,
1039 .bdrv_close = vdi_close,
1040 .bdrv_reopen_prepare = vdi_reopen_prepare,
1041 .bdrv_child_perm = bdrv_default_perms,
1042 .bdrv_co_create = vdi_co_create,
1043 .bdrv_co_create_opts = vdi_co_create_opts,
1044 .bdrv_has_zero_init = vdi_has_zero_init,
1045 .bdrv_co_block_status = vdi_co_block_status,
1046 .bdrv_make_empty = vdi_make_empty,
1047
1048 .bdrv_co_preadv = vdi_co_preadv,
1049 #if defined(CONFIG_VDI_WRITE)
1050 .bdrv_co_pwritev = vdi_co_pwritev,
1051 #endif
1052
1053 .bdrv_co_get_info = vdi_co_get_info,
1054
1055 .is_format = true,
1056 .create_opts = &vdi_create_opts,
1057 .bdrv_co_check = vdi_co_check,
1058 };
1059
bdrv_vdi_init(void)1060 static void bdrv_vdi_init(void)
1061 {
1062 logout("\n");
1063 bdrv_register(&bdrv_vdi);
1064 }
1065
1066 block_init(bdrv_vdi_init);
1067