1 /*
2 * Block driver for the QCOW format
3 *
4 * Copyright (c) 2004-2006 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "qemu/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu/error-report.h"
28 #include "block/block_int.h"
29 #include "block/qdict.h"
30 #include "sysemu/block-backend.h"
31 #include "qemu/module.h"
32 #include "qemu/option.h"
33 #include "qemu/bswap.h"
34 #include "qemu/cutils.h"
35 #include "qemu/memalign.h"
36 #include <zlib.h>
37 #include "qapi/qmp/qdict.h"
38 #include "qapi/qmp/qstring.h"
39 #include "qapi/qobject-input-visitor.h"
40 #include "qapi/qapi-visit-block-core.h"
41 #include "crypto/block.h"
42 #include "migration/blocker.h"
43 #include "crypto.h"
44
45 /**************************************************************/
46 /* QEMU COW block driver with compression and encryption support */
47
48 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
49 #define QCOW_VERSION 1
50
51 #define QCOW_CRYPT_NONE 0
52 #define QCOW_CRYPT_AES 1
53
54 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
55
56 typedef struct QCowHeader {
57 uint32_t magic;
58 uint32_t version;
59 uint64_t backing_file_offset;
60 uint32_t backing_file_size;
61 uint32_t mtime;
62 uint64_t size; /* in bytes */
63 uint8_t cluster_bits;
64 uint8_t l2_bits;
65 uint16_t padding;
66 uint32_t crypt_method;
67 uint64_t l1_table_offset;
68 } QEMU_PACKED QCowHeader;
69
70 #define L2_CACHE_SIZE 16
71
72 typedef struct BDRVQcowState {
73 int cluster_bits;
74 int cluster_size;
75 int l2_bits;
76 int l2_size;
77 unsigned int l1_size;
78 uint64_t cluster_offset_mask;
79 uint64_t l1_table_offset;
80 uint64_t *l1_table;
81 uint64_t *l2_cache;
82 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
83 uint32_t l2_cache_counts[L2_CACHE_SIZE];
84 uint8_t *cluster_cache;
85 uint8_t *cluster_data;
86 uint64_t cluster_cache_offset;
87 QCryptoBlock *crypto; /* Disk encryption format driver */
88 uint32_t crypt_method_header;
89 CoMutex lock;
90 Error *migration_blocker;
91 } BDRVQcowState;
92
93 static QemuOptsList qcow_create_opts;
94
95 static int coroutine_fn GRAPH_RDLOCK
96 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
97
qcow_probe(const uint8_t * buf,int buf_size,const char * filename)98 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
99 {
100 const QCowHeader *cow_header = (const void *)buf;
101
102 if (buf_size >= sizeof(QCowHeader) &&
103 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
104 be32_to_cpu(cow_header->version) == QCOW_VERSION)
105 return 100;
106 else
107 return 0;
108 }
109
qcow_open(BlockDriverState * bs,QDict * options,int flags,Error ** errp)110 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
111 Error **errp)
112 {
113 BDRVQcowState *s = bs->opaque;
114 unsigned int len, i, shift;
115 int ret;
116 QCowHeader header;
117 QCryptoBlockOpenOptions *crypto_opts = NULL;
118 unsigned int cflags = 0;
119 QDict *encryptopts = NULL;
120 const char *encryptfmt;
121
122 qdict_extract_subqdict(options, &encryptopts, "encrypt.");
123 encryptfmt = qdict_get_try_str(encryptopts, "format");
124
125 ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
126 if (ret < 0) {
127 goto fail_unlocked;
128 }
129
130 bdrv_graph_rdlock_main_loop();
131
132 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0);
133 if (ret < 0) {
134 goto fail;
135 }
136 header.magic = be32_to_cpu(header.magic);
137 header.version = be32_to_cpu(header.version);
138 header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
139 header.backing_file_size = be32_to_cpu(header.backing_file_size);
140 header.mtime = be32_to_cpu(header.mtime);
141 header.size = be64_to_cpu(header.size);
142 header.crypt_method = be32_to_cpu(header.crypt_method);
143 header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
144
145 if (header.magic != QCOW_MAGIC) {
146 error_setg(errp, "Image not in qcow format");
147 ret = -EINVAL;
148 goto fail;
149 }
150 if (header.version != QCOW_VERSION) {
151 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32,
152 QCOW_VERSION, header.version);
153 if (header.version == 2 || header.version == 3) {
154 error_append_hint(errp, "Try the 'qcow2' driver instead.\n");
155 }
156
157 ret = -ENOTSUP;
158 goto fail;
159 }
160
161 if (header.size <= 1) {
162 error_setg(errp, "Image size is too small (must be at least 2 bytes)");
163 ret = -EINVAL;
164 goto fail;
165 }
166 if (header.cluster_bits < 9 || header.cluster_bits > 16) {
167 error_setg(errp, "Cluster size must be between 512 and 64k");
168 ret = -EINVAL;
169 goto fail;
170 }
171
172 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
173 * so bytes = num_entries << 3. */
174 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
175 error_setg(errp, "L2 table size must be between 512 and 64k");
176 ret = -EINVAL;
177 goto fail;
178 }
179
180 s->crypt_method_header = header.crypt_method;
181 if (s->crypt_method_header) {
182 if (bdrv_uses_whitelist() &&
183 s->crypt_method_header == QCOW_CRYPT_AES) {
184 error_setg(errp,
185 "Use of AES-CBC encrypted qcow images is no longer "
186 "supported in system emulators");
187 error_append_hint(errp,
188 "You can use 'qemu-img convert' to convert your "
189 "image to an alternative supported format, such "
190 "as unencrypted qcow, or raw with the LUKS "
191 "format instead.\n");
192 ret = -ENOSYS;
193 goto fail;
194 }
195 if (s->crypt_method_header == QCOW_CRYPT_AES) {
196 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
197 error_setg(errp,
198 "Header reported 'aes' encryption format but "
199 "options specify '%s'", encryptfmt);
200 ret = -EINVAL;
201 goto fail;
202 }
203 qdict_put_str(encryptopts, "format", "qcow");
204 crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
205 if (!crypto_opts) {
206 ret = -EINVAL;
207 goto fail;
208 }
209
210 if (flags & BDRV_O_NO_IO) {
211 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
212 }
213 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
214 NULL, NULL, cflags, errp);
215 if (!s->crypto) {
216 ret = -EINVAL;
217 goto fail;
218 }
219 } else {
220 error_setg(errp, "invalid encryption method in qcow header");
221 ret = -EINVAL;
222 goto fail;
223 }
224 bs->encrypted = true;
225 } else {
226 if (encryptfmt) {
227 error_setg(errp, "No encryption in image header, but options "
228 "specified format '%s'", encryptfmt);
229 ret = -EINVAL;
230 goto fail;
231 }
232 }
233 s->cluster_bits = header.cluster_bits;
234 s->cluster_size = 1 << s->cluster_bits;
235 s->l2_bits = header.l2_bits;
236 s->l2_size = 1 << s->l2_bits;
237 bs->total_sectors = header.size / 512;
238 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
239
240 /* read the level 1 table */
241 shift = s->cluster_bits + s->l2_bits;
242 if (header.size > UINT64_MAX - (1LL << shift)) {
243 error_setg(errp, "Image too large");
244 ret = -EINVAL;
245 goto fail;
246 } else {
247 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
248 if (l1_size > INT_MAX / sizeof(uint64_t)) {
249 error_setg(errp, "Image too large");
250 ret = -EINVAL;
251 goto fail;
252 }
253 s->l1_size = l1_size;
254 }
255
256 s->l1_table_offset = header.l1_table_offset;
257 s->l1_table = g_try_new(uint64_t, s->l1_size);
258 if (s->l1_table == NULL) {
259 error_setg(errp, "Could not allocate memory for L1 table");
260 ret = -ENOMEM;
261 goto fail;
262 }
263
264 ret = bdrv_pread(bs->file, s->l1_table_offset,
265 s->l1_size * sizeof(uint64_t), s->l1_table, 0);
266 if (ret < 0) {
267 goto fail;
268 }
269
270 for(i = 0;i < s->l1_size; i++) {
271 s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
272 }
273
274 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
275 s->l2_cache =
276 qemu_try_blockalign(bs->file->bs,
277 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
278 if (s->l2_cache == NULL) {
279 error_setg(errp, "Could not allocate L2 table cache");
280 ret = -ENOMEM;
281 goto fail;
282 }
283 s->cluster_cache = g_malloc(s->cluster_size);
284 s->cluster_data = g_malloc(s->cluster_size);
285 s->cluster_cache_offset = -1;
286
287 /* read the backing file name */
288 if (header.backing_file_offset != 0) {
289 len = header.backing_file_size;
290 if (len > 1023 || len >= sizeof(bs->backing_file)) {
291 error_setg(errp, "Backing file name too long");
292 ret = -EINVAL;
293 goto fail;
294 }
295 ret = bdrv_pread(bs->file, header.backing_file_offset, len,
296 bs->auto_backing_file, 0);
297 if (ret < 0) {
298 goto fail;
299 }
300 bs->auto_backing_file[len] = '\0';
301 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
302 bs->auto_backing_file);
303 }
304
305 /* Disable migration when qcow images are used */
306 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
307 "does not support live migration",
308 bdrv_get_device_or_node_name(bs));
309
310 ret = migrate_add_blocker_normal(&s->migration_blocker, errp);
311 if (ret < 0) {
312 goto fail;
313 }
314
315 qobject_unref(encryptopts);
316 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
317 qemu_co_mutex_init(&s->lock);
318 bdrv_graph_rdunlock_main_loop();
319 return 0;
320
321 fail:
322 bdrv_graph_rdunlock_main_loop();
323 fail_unlocked:
324 g_free(s->l1_table);
325 qemu_vfree(s->l2_cache);
326 g_free(s->cluster_cache);
327 g_free(s->cluster_data);
328 qcrypto_block_free(s->crypto);
329 qobject_unref(encryptopts);
330 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
331 return ret;
332 }
333
334
335 /* We have nothing to do for QCOW reopen, stubs just return
336 * success */
qcow_reopen_prepare(BDRVReopenState * state,BlockReopenQueue * queue,Error ** errp)337 static int qcow_reopen_prepare(BDRVReopenState *state,
338 BlockReopenQueue *queue, Error **errp)
339 {
340 return 0;
341 }
342
343
344 /* 'allocate' is:
345 *
346 * 0 to not allocate.
347 *
348 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
349 * to 'n_end' within the cluster)
350 *
351 * 2 to allocate a compressed cluster of size
352 * 'compressed_size'. 'compressed_size' must be > 0 and <
353 * cluster_size
354 *
355 * return 0 if not allocated, 1 if *result is assigned, and negative
356 * errno on failure.
357 */
358 static int coroutine_fn GRAPH_RDLOCK
get_cluster_offset(BlockDriverState * bs,uint64_t offset,int allocate,int compressed_size,int n_start,int n_end,uint64_t * result)359 get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate,
360 int compressed_size, int n_start, int n_end,
361 uint64_t *result)
362 {
363 BDRVQcowState *s = bs->opaque;
364 int min_index, i, j, l1_index, l2_index, ret;
365 int64_t l2_offset;
366 uint64_t *l2_table, cluster_offset, tmp;
367 uint32_t min_count;
368 int new_l2_table;
369
370 *result = 0;
371 l1_index = offset >> (s->l2_bits + s->cluster_bits);
372 l2_offset = s->l1_table[l1_index];
373 new_l2_table = 0;
374 if (!l2_offset) {
375 if (!allocate)
376 return 0;
377 /* allocate a new l2 entry */
378 l2_offset = bdrv_co_getlength(bs->file->bs);
379 if (l2_offset < 0) {
380 return l2_offset;
381 }
382 /* round to cluster size */
383 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
384 /* update the L1 entry */
385 s->l1_table[l1_index] = l2_offset;
386 tmp = cpu_to_be64(l2_offset);
387 BLKDBG_CO_EVENT(bs->file, BLKDBG_L1_UPDATE);
388 ret = bdrv_co_pwrite_sync(bs->file,
389 s->l1_table_offset + l1_index * sizeof(tmp),
390 sizeof(tmp), &tmp, 0);
391 if (ret < 0) {
392 return ret;
393 }
394 new_l2_table = 1;
395 }
396 for(i = 0; i < L2_CACHE_SIZE; i++) {
397 if (l2_offset == s->l2_cache_offsets[i]) {
398 /* increment the hit count */
399 if (++s->l2_cache_counts[i] == 0xffffffff) {
400 for(j = 0; j < L2_CACHE_SIZE; j++) {
401 s->l2_cache_counts[j] >>= 1;
402 }
403 }
404 l2_table = s->l2_cache + (i << s->l2_bits);
405 goto found;
406 }
407 }
408 /* not found: load a new entry in the least used one */
409 min_index = 0;
410 min_count = 0xffffffff;
411 for(i = 0; i < L2_CACHE_SIZE; i++) {
412 if (s->l2_cache_counts[i] < min_count) {
413 min_count = s->l2_cache_counts[i];
414 min_index = i;
415 }
416 }
417 l2_table = s->l2_cache + (min_index << s->l2_bits);
418 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_LOAD);
419 if (new_l2_table) {
420 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
421 ret = bdrv_co_pwrite_sync(bs->file, l2_offset,
422 s->l2_size * sizeof(uint64_t), l2_table, 0);
423 if (ret < 0) {
424 return ret;
425 }
426 } else {
427 ret = bdrv_co_pread(bs->file, l2_offset,
428 s->l2_size * sizeof(uint64_t), l2_table, 0);
429 if (ret < 0) {
430 return ret;
431 }
432 }
433 s->l2_cache_offsets[min_index] = l2_offset;
434 s->l2_cache_counts[min_index] = 1;
435 found:
436 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
437 cluster_offset = be64_to_cpu(l2_table[l2_index]);
438 if (!cluster_offset ||
439 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
440 if (!allocate)
441 return 0;
442 BLKDBG_CO_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
443 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
444 /* allocate a new cluster */
445 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
446 (n_end - n_start) < s->cluster_size) {
447 /* if the cluster is already compressed, we must
448 decompress it in the case it is not completely
449 overwritten */
450 if (decompress_cluster(bs, cluster_offset) < 0) {
451 return -EIO;
452 }
453 cluster_offset = bdrv_co_getlength(bs->file->bs);
454 if ((int64_t) cluster_offset < 0) {
455 return cluster_offset;
456 }
457 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
458 /* write the cluster content */
459 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
460 ret = bdrv_co_pwrite(bs->file, cluster_offset, s->cluster_size,
461 s->cluster_cache, 0);
462 if (ret < 0) {
463 return ret;
464 }
465 } else {
466 cluster_offset = bdrv_co_getlength(bs->file->bs);
467 if ((int64_t) cluster_offset < 0) {
468 return cluster_offset;
469 }
470 if (allocate == 1) {
471 /* round to cluster size */
472 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
473 if (cluster_offset + s->cluster_size > INT64_MAX) {
474 return -E2BIG;
475 }
476 ret = bdrv_co_truncate(bs->file,
477 cluster_offset + s->cluster_size,
478 false, PREALLOC_MODE_OFF, 0, NULL);
479 if (ret < 0) {
480 return ret;
481 }
482 /* if encrypted, we must initialize the cluster
483 content which won't be written */
484 if (bs->encrypted &&
485 (n_end - n_start) < s->cluster_size) {
486 uint64_t start_offset;
487 assert(s->crypto);
488 start_offset = offset & ~(s->cluster_size - 1);
489 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
490 if (i < n_start || i >= n_end) {
491 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
492 if (qcrypto_block_encrypt(s->crypto,
493 start_offset + i,
494 s->cluster_data,
495 BDRV_SECTOR_SIZE,
496 NULL) < 0) {
497 return -EIO;
498 }
499 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
500 ret = bdrv_co_pwrite(bs->file, cluster_offset + i,
501 BDRV_SECTOR_SIZE,
502 s->cluster_data, 0);
503 if (ret < 0) {
504 return ret;
505 }
506 }
507 }
508 }
509 } else if (allocate == 2) {
510 cluster_offset |= QCOW_OFLAG_COMPRESSED |
511 (uint64_t)compressed_size << (63 - s->cluster_bits);
512 }
513 }
514 /* update L2 table */
515 tmp = cpu_to_be64(cluster_offset);
516 l2_table[l2_index] = tmp;
517 if (allocate == 2) {
518 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
519 } else {
520 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE);
521 }
522 ret = bdrv_co_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
523 sizeof(tmp), &tmp, 0);
524 if (ret < 0) {
525 return ret;
526 }
527 }
528 *result = cluster_offset;
529 return 1;
530 }
531
532 static int coroutine_fn GRAPH_RDLOCK
qcow_co_block_status(BlockDriverState * bs,bool want_zero,int64_t offset,int64_t bytes,int64_t * pnum,int64_t * map,BlockDriverState ** file)533 qcow_co_block_status(BlockDriverState *bs, bool want_zero,
534 int64_t offset, int64_t bytes, int64_t *pnum,
535 int64_t *map, BlockDriverState **file)
536 {
537 BDRVQcowState *s = bs->opaque;
538 int index_in_cluster, ret;
539 int64_t n;
540 uint64_t cluster_offset;
541
542 qemu_co_mutex_lock(&s->lock);
543 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
544 qemu_co_mutex_unlock(&s->lock);
545 if (ret < 0) {
546 return ret;
547 }
548 index_in_cluster = offset & (s->cluster_size - 1);
549 n = s->cluster_size - index_in_cluster;
550 if (n > bytes) {
551 n = bytes;
552 }
553 *pnum = n;
554 if (!cluster_offset) {
555 return 0;
556 }
557 if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
558 return BDRV_BLOCK_DATA | BDRV_BLOCK_COMPRESSED;
559 }
560 if (s->crypto) {
561 return BDRV_BLOCK_DATA;
562 }
563 *map = cluster_offset | index_in_cluster;
564 *file = bs->file->bs;
565 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
566 }
567
decompress_buffer(uint8_t * out_buf,int out_buf_size,const uint8_t * buf,int buf_size)568 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
569 const uint8_t *buf, int buf_size)
570 {
571 z_stream strm1, *strm = &strm1;
572 int ret, out_len;
573
574 memset(strm, 0, sizeof(*strm));
575
576 strm->next_in = (uint8_t *)buf;
577 strm->avail_in = buf_size;
578 strm->next_out = out_buf;
579 strm->avail_out = out_buf_size;
580
581 ret = inflateInit2(strm, -12);
582 if (ret != Z_OK)
583 return -1;
584 ret = inflate(strm, Z_FINISH);
585 out_len = strm->next_out - out_buf;
586 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
587 out_len != out_buf_size) {
588 inflateEnd(strm);
589 return -1;
590 }
591 inflateEnd(strm);
592 return 0;
593 }
594
595 static int coroutine_fn GRAPH_RDLOCK
decompress_cluster(BlockDriverState * bs,uint64_t cluster_offset)596 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
597 {
598 BDRVQcowState *s = bs->opaque;
599 int ret, csize;
600 uint64_t coffset;
601
602 coffset = cluster_offset & s->cluster_offset_mask;
603 if (s->cluster_cache_offset != coffset) {
604 csize = cluster_offset >> (63 - s->cluster_bits);
605 csize &= (s->cluster_size - 1);
606 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
607 ret = bdrv_co_pread(bs->file, coffset, csize, s->cluster_data, 0);
608 if (ret < 0)
609 return -1;
610 if (decompress_buffer(s->cluster_cache, s->cluster_size,
611 s->cluster_data, csize) < 0) {
612 return -1;
613 }
614 s->cluster_cache_offset = coffset;
615 }
616 return 0;
617 }
618
qcow_refresh_limits(BlockDriverState * bs,Error ** errp)619 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
620 {
621 /* At least encrypted images require 512-byte alignment. Apply the
622 * limit universally, rather than just on encrypted images, as
623 * it's easier to let the block layer handle rounding than to
624 * audit this code further. */
625 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
626 }
627
628 static int coroutine_fn GRAPH_RDLOCK
qcow_co_preadv(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)629 qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
630 QEMUIOVector *qiov, BdrvRequestFlags flags)
631 {
632 BDRVQcowState *s = bs->opaque;
633 int offset_in_cluster;
634 int ret = 0, n;
635 uint64_t cluster_offset;
636 uint8_t *buf;
637 void *orig_buf;
638
639 if (qiov->niov > 1) {
640 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
641 if (buf == NULL) {
642 return -ENOMEM;
643 }
644 } else {
645 orig_buf = NULL;
646 buf = (uint8_t *)qiov->iov->iov_base;
647 }
648
649 qemu_co_mutex_lock(&s->lock);
650
651 while (bytes != 0) {
652 /* prepare next request */
653 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
654 if (ret < 0) {
655 break;
656 }
657 offset_in_cluster = offset & (s->cluster_size - 1);
658 n = s->cluster_size - offset_in_cluster;
659 if (n > bytes) {
660 n = bytes;
661 }
662
663 if (!cluster_offset) {
664 if (bs->backing) {
665 /* read from the base image */
666 qemu_co_mutex_unlock(&s->lock);
667 /* qcow2 emits this on bs->file instead of bs->backing */
668 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
669 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
670 qemu_co_mutex_lock(&s->lock);
671 if (ret < 0) {
672 break;
673 }
674 } else {
675 /* Note: in this case, no need to wait */
676 memset(buf, 0, n);
677 }
678 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
679 /* add AIO support for compressed blocks ? */
680 if (decompress_cluster(bs, cluster_offset) < 0) {
681 ret = -EIO;
682 break;
683 }
684 memcpy(buf, s->cluster_cache + offset_in_cluster, n);
685 } else {
686 if ((cluster_offset & 511) != 0) {
687 ret = -EIO;
688 break;
689 }
690 qemu_co_mutex_unlock(&s->lock);
691 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_AIO);
692 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
693 n, buf, 0);
694 qemu_co_mutex_lock(&s->lock);
695 if (ret < 0) {
696 break;
697 }
698 if (bs->encrypted) {
699 assert(s->crypto);
700 if (qcrypto_block_decrypt(s->crypto,
701 offset, buf, n, NULL) < 0) {
702 ret = -EIO;
703 break;
704 }
705 }
706 }
707 ret = 0;
708
709 bytes -= n;
710 offset += n;
711 buf += n;
712 }
713
714 qemu_co_mutex_unlock(&s->lock);
715
716 if (qiov->niov > 1) {
717 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
718 qemu_vfree(orig_buf);
719 }
720
721 return ret;
722 }
723
724 static int coroutine_fn GRAPH_RDLOCK
qcow_co_pwritev(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov,BdrvRequestFlags flags)725 qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
726 QEMUIOVector *qiov, BdrvRequestFlags flags)
727 {
728 BDRVQcowState *s = bs->opaque;
729 int offset_in_cluster;
730 uint64_t cluster_offset;
731 int ret = 0, n;
732 uint8_t *buf;
733 void *orig_buf;
734
735 s->cluster_cache_offset = -1; /* disable compressed cache */
736
737 /* We must always copy the iov when encrypting, so we
738 * don't modify the original data buffer during encryption */
739 if (bs->encrypted || qiov->niov > 1) {
740 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
741 if (buf == NULL) {
742 return -ENOMEM;
743 }
744 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
745 } else {
746 orig_buf = NULL;
747 buf = (uint8_t *)qiov->iov->iov_base;
748 }
749
750 qemu_co_mutex_lock(&s->lock);
751
752 while (bytes != 0) {
753 offset_in_cluster = offset & (s->cluster_size - 1);
754 n = s->cluster_size - offset_in_cluster;
755 if (n > bytes) {
756 n = bytes;
757 }
758 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
759 offset_in_cluster + n, &cluster_offset);
760 if (ret < 0) {
761 break;
762 }
763 if (!cluster_offset || (cluster_offset & 511) != 0) {
764 ret = -EIO;
765 break;
766 }
767 if (bs->encrypted) {
768 assert(s->crypto);
769 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
770 ret = -EIO;
771 break;
772 }
773 }
774
775 qemu_co_mutex_unlock(&s->lock);
776 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
777 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
778 n, buf, 0);
779 qemu_co_mutex_lock(&s->lock);
780 if (ret < 0) {
781 break;
782 }
783 ret = 0;
784
785 bytes -= n;
786 offset += n;
787 buf += n;
788 }
789 qemu_co_mutex_unlock(&s->lock);
790
791 qemu_vfree(orig_buf);
792
793 return ret;
794 }
795
qcow_close(BlockDriverState * bs)796 static void qcow_close(BlockDriverState *bs)
797 {
798 BDRVQcowState *s = bs->opaque;
799
800 qcrypto_block_free(s->crypto);
801 s->crypto = NULL;
802 g_free(s->l1_table);
803 qemu_vfree(s->l2_cache);
804 g_free(s->cluster_cache);
805 g_free(s->cluster_data);
806
807 migrate_del_blocker(&s->migration_blocker);
808 }
809
810 static int coroutine_fn GRAPH_UNLOCKED
qcow_co_create(BlockdevCreateOptions * opts,Error ** errp)811 qcow_co_create(BlockdevCreateOptions *opts, Error **errp)
812 {
813 BlockdevCreateOptionsQcow *qcow_opts;
814 int header_size, backing_filename_len, l1_size, shift, i;
815 QCowHeader header;
816 uint8_t *tmp;
817 int64_t total_size = 0;
818 int ret;
819 BlockDriverState *bs;
820 BlockBackend *qcow_blk;
821 QCryptoBlock *crypto = NULL;
822
823 assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
824 qcow_opts = &opts->u.qcow;
825
826 /* Sanity checks */
827 total_size = qcow_opts->size;
828 if (total_size == 0) {
829 error_setg(errp, "Image size is too small, cannot be zero length");
830 return -EINVAL;
831 }
832
833 if (qcow_opts->encrypt &&
834 qcow_opts->encrypt->format != QCRYPTO_BLOCK_FORMAT_QCOW)
835 {
836 error_setg(errp, "Unsupported encryption format");
837 return -EINVAL;
838 }
839
840 /* Create BlockBackend to write to the image */
841 bs = bdrv_co_open_blockdev_ref(qcow_opts->file, errp);
842 if (bs == NULL) {
843 return -EIO;
844 }
845
846 qcow_blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
847 BLK_PERM_ALL, errp);
848 if (!qcow_blk) {
849 ret = -EPERM;
850 goto exit;
851 }
852 blk_set_allow_write_beyond_eof(qcow_blk, true);
853
854 /* Create image format */
855 memset(&header, 0, sizeof(header));
856 header.magic = cpu_to_be32(QCOW_MAGIC);
857 header.version = cpu_to_be32(QCOW_VERSION);
858 header.size = cpu_to_be64(total_size);
859 header_size = sizeof(header);
860 backing_filename_len = 0;
861 if (qcow_opts->backing_file) {
862 if (strcmp(qcow_opts->backing_file, "fat:")) {
863 header.backing_file_offset = cpu_to_be64(header_size);
864 backing_filename_len = strlen(qcow_opts->backing_file);
865 header.backing_file_size = cpu_to_be32(backing_filename_len);
866 header_size += backing_filename_len;
867 } else {
868 /* special backing file for vvfat */
869 qcow_opts->backing_file = NULL;
870 }
871 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
872 unmodified sectors */
873 header.l2_bits = 12; /* 32 KB L2 tables */
874 } else {
875 header.cluster_bits = 12; /* 4 KB clusters */
876 header.l2_bits = 9; /* 4 KB L2 tables */
877 }
878 header_size = (header_size + 7) & ~7;
879 shift = header.cluster_bits + header.l2_bits;
880 l1_size = (total_size + (1LL << shift) - 1) >> shift;
881
882 header.l1_table_offset = cpu_to_be64(header_size);
883
884 if (qcow_opts->encrypt) {
885 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
886
887 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
888 NULL, NULL, NULL, 0, errp);
889 if (!crypto) {
890 ret = -EINVAL;
891 goto exit;
892 }
893 } else {
894 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
895 }
896
897 /* write all the data */
898 ret = blk_co_pwrite(qcow_blk, 0, sizeof(header), &header, 0);
899 if (ret < 0) {
900 goto exit;
901 }
902
903 if (qcow_opts->backing_file) {
904 ret = blk_co_pwrite(qcow_blk, sizeof(header), backing_filename_len,
905 qcow_opts->backing_file, 0);
906 if (ret < 0) {
907 goto exit;
908 }
909 }
910
911 tmp = g_malloc0(BDRV_SECTOR_SIZE);
912 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
913 i++) {
914 ret = blk_co_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
915 BDRV_SECTOR_SIZE, tmp, 0);
916 if (ret < 0) {
917 g_free(tmp);
918 goto exit;
919 }
920 }
921
922 g_free(tmp);
923 ret = 0;
924 exit:
925 blk_co_unref(qcow_blk);
926 bdrv_co_unref(bs);
927 qcrypto_block_free(crypto);
928 return ret;
929 }
930
931 static int coroutine_fn GRAPH_UNLOCKED
qcow_co_create_opts(BlockDriver * drv,const char * filename,QemuOpts * opts,Error ** errp)932 qcow_co_create_opts(BlockDriver *drv, const char *filename,
933 QemuOpts *opts, Error **errp)
934 {
935 BlockdevCreateOptions *create_options = NULL;
936 BlockDriverState *bs = NULL;
937 QDict *qdict = NULL;
938 Visitor *v;
939 const char *val;
940 int ret;
941 char *backing_fmt;
942
943 static const QDictRenames opt_renames[] = {
944 { BLOCK_OPT_BACKING_FILE, "backing-file" },
945 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
946 { NULL, NULL },
947 };
948
949 /*
950 * We can't actually store a backing format, but can check that
951 * the user's request made sense.
952 */
953 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
954 if (backing_fmt && !bdrv_find_format(backing_fmt)) {
955 error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
956 ret = -EINVAL;
957 goto fail;
958 }
959
960 /* Parse options and convert legacy syntax */
961 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
962
963 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
964 if (val && !strcmp(val, "on")) {
965 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
966 } else if (val && !strcmp(val, "off")) {
967 qdict_del(qdict, BLOCK_OPT_ENCRYPT);
968 }
969
970 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
971 if (val && !strcmp(val, "aes")) {
972 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
973 }
974
975 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
976 ret = -EINVAL;
977 goto fail;
978 }
979
980 /* Create and open the file (protocol layer) */
981 ret = bdrv_co_create_file(filename, opts, errp);
982 if (ret < 0) {
983 goto fail;
984 }
985
986 bs = bdrv_co_open(filename, NULL, NULL,
987 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
988 if (bs == NULL) {
989 ret = -EIO;
990 goto fail;
991 }
992
993 /* Now get the QAPI type BlockdevCreateOptions */
994 qdict_put_str(qdict, "driver", "qcow");
995 qdict_put_str(qdict, "file", bs->node_name);
996
997 v = qobject_input_visitor_new_flat_confused(qdict, errp);
998 if (!v) {
999 ret = -EINVAL;
1000 goto fail;
1001 }
1002
1003 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
1004 visit_free(v);
1005 if (!create_options) {
1006 ret = -EINVAL;
1007 goto fail;
1008 }
1009
1010 /* Silently round up size */
1011 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1012 create_options->u.qcow.size =
1013 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1014
1015 /* Create the qcow image (format layer) */
1016 ret = qcow_co_create(create_options, errp);
1017 if (ret < 0) {
1018 goto fail;
1019 }
1020
1021 ret = 0;
1022 fail:
1023 g_free(backing_fmt);
1024 qobject_unref(qdict);
1025 bdrv_co_unref(bs);
1026 qapi_free_BlockdevCreateOptions(create_options);
1027 return ret;
1028 }
1029
qcow_make_empty(BlockDriverState * bs)1030 static int GRAPH_RDLOCK qcow_make_empty(BlockDriverState *bs)
1031 {
1032 BDRVQcowState *s = bs->opaque;
1033 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1034 int ret;
1035
1036 memset(s->l1_table, 0, l1_length);
1037 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table,
1038 0) < 0)
1039 return -1;
1040 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1041 PREALLOC_MODE_OFF, 0, NULL);
1042 if (ret < 0)
1043 return ret;
1044
1045 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1046 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1047 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1048
1049 return 0;
1050 }
1051
1052 /* XXX: put compressed sectors first, then all the cluster aligned
1053 tables to avoid losing bytes in alignment */
1054 static int coroutine_fn GRAPH_RDLOCK
qcow_co_pwritev_compressed(BlockDriverState * bs,int64_t offset,int64_t bytes,QEMUIOVector * qiov)1055 qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes,
1056 QEMUIOVector *qiov)
1057 {
1058 BDRVQcowState *s = bs->opaque;
1059 z_stream strm;
1060 int ret, out_len;
1061 uint8_t *buf, *out_buf;
1062 uint64_t cluster_offset;
1063
1064 buf = qemu_blockalign(bs, s->cluster_size);
1065 if (bytes != s->cluster_size) {
1066 if (bytes > s->cluster_size ||
1067 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1068 {
1069 qemu_vfree(buf);
1070 return -EINVAL;
1071 }
1072 /* Zero-pad last write if image size is not cluster aligned */
1073 memset(buf + bytes, 0, s->cluster_size - bytes);
1074 }
1075 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1076
1077 out_buf = g_malloc(s->cluster_size);
1078
1079 /* best compression, small window, no zlib header */
1080 memset(&strm, 0, sizeof(strm));
1081 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1082 Z_DEFLATED, -12,
1083 9, Z_DEFAULT_STRATEGY);
1084 if (ret != 0) {
1085 ret = -EINVAL;
1086 goto fail;
1087 }
1088
1089 strm.avail_in = s->cluster_size;
1090 strm.next_in = (uint8_t *)buf;
1091 strm.avail_out = s->cluster_size;
1092 strm.next_out = out_buf;
1093
1094 ret = deflate(&strm, Z_FINISH);
1095 if (ret != Z_STREAM_END && ret != Z_OK) {
1096 deflateEnd(&strm);
1097 ret = -EINVAL;
1098 goto fail;
1099 }
1100 out_len = strm.next_out - out_buf;
1101
1102 deflateEnd(&strm);
1103
1104 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1105 /* could not compress: write normal cluster */
1106 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1107 if (ret < 0) {
1108 goto fail;
1109 }
1110 goto success;
1111 }
1112 qemu_co_mutex_lock(&s->lock);
1113 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1114 qemu_co_mutex_unlock(&s->lock);
1115 if (ret < 0) {
1116 goto fail;
1117 }
1118 if (cluster_offset == 0) {
1119 ret = -EIO;
1120 goto fail;
1121 }
1122 cluster_offset &= s->cluster_offset_mask;
1123
1124 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1125 ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1126 if (ret < 0) {
1127 goto fail;
1128 }
1129 success:
1130 ret = 0;
1131 fail:
1132 qemu_vfree(buf);
1133 g_free(out_buf);
1134 return ret;
1135 }
1136
1137 static int coroutine_fn
qcow_co_get_info(BlockDriverState * bs,BlockDriverInfo * bdi)1138 qcow_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1139 {
1140 BDRVQcowState *s = bs->opaque;
1141 bdi->cluster_size = s->cluster_size;
1142 return 0;
1143 }
1144
1145 static QemuOptsList qcow_create_opts = {
1146 .name = "qcow-create-opts",
1147 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1148 .desc = {
1149 {
1150 .name = BLOCK_OPT_SIZE,
1151 .type = QEMU_OPT_SIZE,
1152 .help = "Virtual disk size"
1153 },
1154 {
1155 .name = BLOCK_OPT_BACKING_FILE,
1156 .type = QEMU_OPT_STRING,
1157 .help = "File name of a base image"
1158 },
1159 {
1160 .name = BLOCK_OPT_BACKING_FMT,
1161 .type = QEMU_OPT_STRING,
1162 .help = "Format of the backing image",
1163 },
1164 {
1165 .name = BLOCK_OPT_ENCRYPT,
1166 .type = QEMU_OPT_BOOL,
1167 .help = "Encrypt the image with format 'aes'. (Deprecated "
1168 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1169 },
1170 {
1171 .name = BLOCK_OPT_ENCRYPT_FORMAT,
1172 .type = QEMU_OPT_STRING,
1173 .help = "Encrypt the image, format choices: 'aes'",
1174 },
1175 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1176 { /* end of list */ }
1177 }
1178 };
1179
1180 static const char *const qcow_strong_runtime_opts[] = {
1181 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1182
1183 NULL
1184 };
1185
1186 static BlockDriver bdrv_qcow = {
1187 .format_name = "qcow",
1188 .instance_size = sizeof(BDRVQcowState),
1189 .bdrv_probe = qcow_probe,
1190 .bdrv_open = qcow_open,
1191 .bdrv_close = qcow_close,
1192 .bdrv_child_perm = bdrv_default_perms,
1193 .bdrv_reopen_prepare = qcow_reopen_prepare,
1194 .bdrv_co_create = qcow_co_create,
1195 .bdrv_co_create_opts = qcow_co_create_opts,
1196 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1197 .is_format = true,
1198 .supports_backing = true,
1199 .bdrv_refresh_limits = qcow_refresh_limits,
1200
1201 .bdrv_co_preadv = qcow_co_preadv,
1202 .bdrv_co_pwritev = qcow_co_pwritev,
1203 .bdrv_co_block_status = qcow_co_block_status,
1204
1205 .bdrv_make_empty = qcow_make_empty,
1206 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1207 .bdrv_co_get_info = qcow_co_get_info,
1208
1209 .create_opts = &qcow_create_opts,
1210 .strong_runtime_opts = qcow_strong_runtime_opts,
1211 };
1212
bdrv_qcow_init(void)1213 static void bdrv_qcow_init(void)
1214 {
1215 bdrv_register(&bdrv_qcow);
1216 }
1217
1218 block_init(bdrv_qcow_init);
1219