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linux-user: Check sigsetsize argument to syscalls
[qemu/kevin.git] / block / qcow.c
blob0c7b75bc76638944d4522f3705d37309ab07784b
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 #include "qemu/osdep.h"
25 #include "qapi/error.h"
26 #include "qemu-common.h"
27 #include "qemu/error-report.h"
28 #include "block/block_int.h"
29 #include "sysemu/block-backend.h"
30 #include "qemu/module.h"
31 #include "qemu/bswap.h"
32 #include <zlib.h>
33 #include "qapi/qmp/qerror.h"
34 #include "crypto/cipher.h"
35 #include "migration/migration.h"
36
37 /**************************************************************/
38 /* QEMU COW block driver with compression and encryption support */
39
40 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
41 #define QCOW_VERSION 1
42
43 #define QCOW_CRYPT_NONE 0
44 #define QCOW_CRYPT_AES 1
45
46 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
47
48 typedef struct QCowHeader {
49 uint32_t magic;
50 uint32_t version;
51 uint64_t backing_file_offset;
52 uint32_t backing_file_size;
53 uint32_t mtime;
54 uint64_t size; /* in bytes */
55 uint8_t cluster_bits;
56 uint8_t l2_bits;
57 uint16_t padding;
58 uint32_t crypt_method;
59 uint64_t l1_table_offset;
60 } QEMU_PACKED QCowHeader;
61
62 #define L2_CACHE_SIZE 16
63
64 typedef struct BDRVQcowState {
65 int cluster_bits;
66 int cluster_size;
67 int cluster_sectors;
68 int l2_bits;
69 int l2_size;
70 unsigned int l1_size;
71 uint64_t cluster_offset_mask;
72 uint64_t l1_table_offset;
73 uint64_t *l1_table;
74 uint64_t *l2_cache;
75 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
76 uint32_t l2_cache_counts[L2_CACHE_SIZE];
77 uint8_t *cluster_cache;
78 uint8_t *cluster_data;
79 uint64_t cluster_cache_offset;
80 QCryptoCipher *cipher; /* NULL if no key yet */
81 uint32_t crypt_method_header;
82 CoMutex lock;
83 Error *migration_blocker;
84 } BDRVQcowState;
85
86 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
87
88 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
89 {
90 const QCowHeader *cow_header = (const void *)buf;
91
92 if (buf_size >= sizeof(QCowHeader) &&
93 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
94 be32_to_cpu(cow_header->version) == QCOW_VERSION)
95 return 100;
96 else
97 return 0;
98 }
99
100 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
101 Error **errp)
102 {
103 BDRVQcowState *s = bs->opaque;
104 unsigned int len, i, shift;
105 int ret;
106 QCowHeader header;
107
108 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
109 if (ret < 0) {
110 goto fail;
111 }
112 be32_to_cpus(&header.magic);
113 be32_to_cpus(&header.version);
114 be64_to_cpus(&header.backing_file_offset);
115 be32_to_cpus(&header.backing_file_size);
116 be32_to_cpus(&header.mtime);
117 be64_to_cpus(&header.size);
118 be32_to_cpus(&header.crypt_method);
119 be64_to_cpus(&header.l1_table_offset);
120
121 if (header.magic != QCOW_MAGIC) {
122 error_setg(errp, "Image not in qcow format");
123 ret = -EINVAL;
124 goto fail;
125 }
126 if (header.version != QCOW_VERSION) {
127 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version);
128 ret = -ENOTSUP;
129 goto fail;
130 }
131
132 if (header.size <= 1) {
133 error_setg(errp, "Image size is too small (must be at least 2 bytes)");
134 ret = -EINVAL;
135 goto fail;
136 }
137 if (header.cluster_bits < 9 || header.cluster_bits > 16) {
138 error_setg(errp, "Cluster size must be between 512 and 64k");
139 ret = -EINVAL;
140 goto fail;
141 }
142
143 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
144 * so bytes = num_entries << 3. */
145 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
146 error_setg(errp, "L2 table size must be between 512 and 64k");
147 ret = -EINVAL;
148 goto fail;
149 }
150
151 if (header.crypt_method > QCOW_CRYPT_AES) {
152 error_setg(errp, "invalid encryption method in qcow header");
153 ret = -EINVAL;
154 goto fail;
155 }
156 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
157 error_setg(errp, "AES cipher not available");
158 ret = -EINVAL;
159 goto fail;
160 }
161 s->crypt_method_header = header.crypt_method;
162 if (s->crypt_method_header) {
163 if (bdrv_uses_whitelist() &&
164 s->crypt_method_header == QCOW_CRYPT_AES) {
165 error_setg(errp,
166 "Use of AES-CBC encrypted qcow images is no longer "
167 "supported in system emulators");
168 error_append_hint(errp,
169 "You can use 'qemu-img convert' to convert your "
170 "image to an alternative supported format, such "
171 "as unencrypted qcow, or raw with the LUKS "
172 "format instead.\n");
173 ret = -ENOSYS;
174 goto fail;
175 }
176
177 bs->encrypted = true;
178 }
179 s->cluster_bits = header.cluster_bits;
180 s->cluster_size = 1 << s->cluster_bits;
181 s->cluster_sectors = 1 << (s->cluster_bits - 9);
182 s->l2_bits = header.l2_bits;
183 s->l2_size = 1 << s->l2_bits;
184 bs->total_sectors = header.size / 512;
185 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
186
187 /* read the level 1 table */
188 shift = s->cluster_bits + s->l2_bits;
189 if (header.size > UINT64_MAX - (1LL << shift)) {
190 error_setg(errp, "Image too large");
191 ret = -EINVAL;
192 goto fail;
193 } else {
194 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
195 if (l1_size > INT_MAX / sizeof(uint64_t)) {
196 error_setg(errp, "Image too large");
197 ret = -EINVAL;
198 goto fail;
199 }
200 s->l1_size = l1_size;
201 }
202
203 s->l1_table_offset = header.l1_table_offset;
204 s->l1_table = g_try_new(uint64_t, s->l1_size);
205 if (s->l1_table == NULL) {
206 error_setg(errp, "Could not allocate memory for L1 table");
207 ret = -ENOMEM;
208 goto fail;
209 }
210
211 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
212 s->l1_size * sizeof(uint64_t));
213 if (ret < 0) {
214 goto fail;
215 }
216
217 for(i = 0;i < s->l1_size; i++) {
218 be64_to_cpus(&s->l1_table[i]);
219 }
220
221 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
222 s->l2_cache =
223 qemu_try_blockalign(bs->file->bs,
224 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
225 if (s->l2_cache == NULL) {
226 error_setg(errp, "Could not allocate L2 table cache");
227 ret = -ENOMEM;
228 goto fail;
229 }
230 s->cluster_cache = g_malloc(s->cluster_size);
231 s->cluster_data = g_malloc(s->cluster_size);
232 s->cluster_cache_offset = -1;
233
234 /* read the backing file name */
235 if (header.backing_file_offset != 0) {
236 len = header.backing_file_size;
237 if (len > 1023 || len >= sizeof(bs->backing_file)) {
238 error_setg(errp, "Backing file name too long");
239 ret = -EINVAL;
240 goto fail;
241 }
242 ret = bdrv_pread(bs->file, header.backing_file_offset,
243 bs->backing_file, len);
244 if (ret < 0) {
245 goto fail;
246 }
247 bs->backing_file[len] = '\0';
248 }
249
250 /* Disable migration when qcow images are used */
251 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
252 "does not support live migration",
253 bdrv_get_device_or_node_name(bs));
254 migrate_add_blocker(s->migration_blocker);
255
256 qemu_co_mutex_init(&s->lock);
257 return 0;
258
259 fail:
260 g_free(s->l1_table);
261 qemu_vfree(s->l2_cache);
262 g_free(s->cluster_cache);
263 g_free(s->cluster_data);
264 return ret;
265 }
266
267
268 /* We have nothing to do for QCOW reopen, stubs just return
269 * success */
270 static int qcow_reopen_prepare(BDRVReopenState *state,
271 BlockReopenQueue *queue, Error **errp)
272 {
273 return 0;
274 }
275
276 static int qcow_set_key(BlockDriverState *bs, const char *key)
277 {
278 BDRVQcowState *s = bs->opaque;
279 uint8_t keybuf[16];
280 int len, i;
281 Error *err;
282
283 memset(keybuf, 0, 16);
284 len = strlen(key);
285 if (len > 16)
286 len = 16;
287 /* XXX: we could compress the chars to 7 bits to increase
288 entropy */
289 for(i = 0;i < len;i++) {
290 keybuf[i] = key[i];
291 }
292 assert(bs->encrypted);
293
294 qcrypto_cipher_free(s->cipher);
295 s->cipher = qcrypto_cipher_new(
296 QCRYPTO_CIPHER_ALG_AES_128,
297 QCRYPTO_CIPHER_MODE_CBC,
298 keybuf, G_N_ELEMENTS(keybuf),
299 &err);
300
301 if (!s->cipher) {
302 /* XXX would be nice if errors in this method could
303 * be properly propagate to the caller. Would need
304 * the bdrv_set_key() API signature to be fixed. */
305 error_free(err);
306 return -1;
307 }
308 return 0;
309 }
310
311 /* The crypt function is compatible with the linux cryptoloop
312 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
313 supported */
314 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
315 uint8_t *out_buf, const uint8_t *in_buf,
316 int nb_sectors, bool enc, Error **errp)
317 {
318 union {
319 uint64_t ll[2];
320 uint8_t b[16];
321 } ivec;
322 int i;
323 int ret;
324
325 for(i = 0; i < nb_sectors; i++) {
326 ivec.ll[0] = cpu_to_le64(sector_num);
327 ivec.ll[1] = 0;
328 if (qcrypto_cipher_setiv(s->cipher,
329 ivec.b, G_N_ELEMENTS(ivec.b),
330 errp) < 0) {
331 return -1;
332 }
333 if (enc) {
334 ret = qcrypto_cipher_encrypt(s->cipher,
335 in_buf,
336 out_buf,
337 512,
338 errp);
339 } else {
340 ret = qcrypto_cipher_decrypt(s->cipher,
341 in_buf,
342 out_buf,
343 512,
344 errp);
345 }
346 if (ret < 0) {
347 return -1;
348 }
349 sector_num++;
350 in_buf += 512;
351 out_buf += 512;
352 }
353 return 0;
354 }
355
356 /* 'allocate' is:
357 *
358 * 0 to not allocate.
359 *
360 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
361 * 'n_end')
362 *
363 * 2 to allocate a compressed cluster of size
364 * 'compressed_size'. 'compressed_size' must be > 0 and <
365 * cluster_size
366 *
367 * return 0 if not allocated.
368 */
369 static uint64_t get_cluster_offset(BlockDriverState *bs,
370 uint64_t offset, int allocate,
371 int compressed_size,
372 int n_start, int n_end)
373 {
374 BDRVQcowState *s = bs->opaque;
375 int min_index, i, j, l1_index, l2_index;
376 uint64_t l2_offset, *l2_table, cluster_offset, tmp;
377 uint32_t min_count;
378 int new_l2_table;
379
380 l1_index = offset >> (s->l2_bits + s->cluster_bits);
381 l2_offset = s->l1_table[l1_index];
382 new_l2_table = 0;
383 if (!l2_offset) {
384 if (!allocate)
385 return 0;
386 /* allocate a new l2 entry */
387 l2_offset = bdrv_getlength(bs->file->bs);
388 /* round to cluster size */
389 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
390 /* update the L1 entry */
391 s->l1_table[l1_index] = l2_offset;
392 tmp = cpu_to_be64(l2_offset);
393 if (bdrv_pwrite_sync(bs->file,
394 s->l1_table_offset + l1_index * sizeof(tmp),
395 &tmp, sizeof(tmp)) < 0)
396 return 0;
397 new_l2_table = 1;
398 }
399 for(i = 0; i < L2_CACHE_SIZE; i++) {
400 if (l2_offset == s->l2_cache_offsets[i]) {
401 /* increment the hit count */
402 if (++s->l2_cache_counts[i] == 0xffffffff) {
403 for(j = 0; j < L2_CACHE_SIZE; j++) {
404 s->l2_cache_counts[j] >>= 1;
405 }
406 }
407 l2_table = s->l2_cache + (i << s->l2_bits);
408 goto found;
409 }
410 }
411 /* not found: load a new entry in the least used one */
412 min_index = 0;
413 min_count = 0xffffffff;
414 for(i = 0; i < L2_CACHE_SIZE; i++) {
415 if (s->l2_cache_counts[i] < min_count) {
416 min_count = s->l2_cache_counts[i];
417 min_index = i;
418 }
419 }
420 l2_table = s->l2_cache + (min_index << s->l2_bits);
421 if (new_l2_table) {
422 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
423 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
424 s->l2_size * sizeof(uint64_t)) < 0)
425 return 0;
426 } else {
427 if (bdrv_pread(bs->file, l2_offset, l2_table,
428 s->l2_size * sizeof(uint64_t)) !=
429 s->l2_size * sizeof(uint64_t))
430 return 0;
431 }
432 s->l2_cache_offsets[min_index] = l2_offset;
433 s->l2_cache_counts[min_index] = 1;
434 found:
435 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
436 cluster_offset = be64_to_cpu(l2_table[l2_index]);
437 if (!cluster_offset ||
438 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
439 if (!allocate)
440 return 0;
441 /* allocate a new cluster */
442 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
443 (n_end - n_start) < s->cluster_sectors) {
444 /* if the cluster is already compressed, we must
445 decompress it in the case it is not completely
446 overwritten */
447 if (decompress_cluster(bs, cluster_offset) < 0)
448 return 0;
449 cluster_offset = bdrv_getlength(bs->file->bs);
450 cluster_offset = (cluster_offset + s->cluster_size - 1) &
451 ~(s->cluster_size - 1);
452 /* write the cluster content */
453 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache,
454 s->cluster_size) !=
455 s->cluster_size)
456 return -1;
457 } else {
458 cluster_offset = bdrv_getlength(bs->file->bs);
459 if (allocate == 1) {
460 /* round to cluster size */
461 cluster_offset = (cluster_offset + s->cluster_size - 1) &
462 ~(s->cluster_size - 1);
463 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size);
464 /* if encrypted, we must initialize the cluster
465 content which won't be written */
466 if (bs->encrypted &&
467 (n_end - n_start) < s->cluster_sectors) {
468 uint64_t start_sect;
469 assert(s->cipher);
470 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
471 memset(s->cluster_data + 512, 0x00, 512);
472 for(i = 0; i < s->cluster_sectors; i++) {
473 if (i < n_start || i >= n_end) {
474 Error *err = NULL;
475 if (encrypt_sectors(s, start_sect + i,
476 s->cluster_data,
477 s->cluster_data + 512, 1,
478 true, &err) < 0) {
479 error_free(err);
480 errno = EIO;
481 return -1;
482 }
483 if (bdrv_pwrite(bs->file,
484 cluster_offset + i * 512,
485 s->cluster_data, 512) != 512)
486 return -1;
487 }
488 }
489 }
490 } else if (allocate == 2) {
491 cluster_offset |= QCOW_OFLAG_COMPRESSED |
492 (uint64_t)compressed_size << (63 - s->cluster_bits);
493 }
494 }
495 /* update L2 table */
496 tmp = cpu_to_be64(cluster_offset);
497 l2_table[l2_index] = tmp;
498 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
499 &tmp, sizeof(tmp)) < 0)
500 return 0;
501 }
502 return cluster_offset;
503 }
504
505 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
506 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
507 {
508 BDRVQcowState *s = bs->opaque;
509 int index_in_cluster, n;
510 uint64_t cluster_offset;
511
512 qemu_co_mutex_lock(&s->lock);
513 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
514 qemu_co_mutex_unlock(&s->lock);
515 index_in_cluster = sector_num & (s->cluster_sectors - 1);
516 n = s->cluster_sectors - index_in_cluster;
517 if (n > nb_sectors)
518 n = nb_sectors;
519 *pnum = n;
520 if (!cluster_offset) {
521 return 0;
522 }
523 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) {
524 return BDRV_BLOCK_DATA;
525 }
526 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
527 *file = bs->file->bs;
528 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset;
529 }
530
531 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
532 const uint8_t *buf, int buf_size)
533 {
534 z_stream strm1, *strm = &strm1;
535 int ret, out_len;
536
537 memset(strm, 0, sizeof(*strm));
538
539 strm->next_in = (uint8_t *)buf;
540 strm->avail_in = buf_size;
541 strm->next_out = out_buf;
542 strm->avail_out = out_buf_size;
543
544 ret = inflateInit2(strm, -12);
545 if (ret != Z_OK)
546 return -1;
547 ret = inflate(strm, Z_FINISH);
548 out_len = strm->next_out - out_buf;
549 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
550 out_len != out_buf_size) {
551 inflateEnd(strm);
552 return -1;
553 }
554 inflateEnd(strm);
555 return 0;
556 }
557
558 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
559 {
560 BDRVQcowState *s = bs->opaque;
561 int ret, csize;
562 uint64_t coffset;
563
564 coffset = cluster_offset & s->cluster_offset_mask;
565 if (s->cluster_cache_offset != coffset) {
566 csize = cluster_offset >> (63 - s->cluster_bits);
567 csize &= (s->cluster_size - 1);
568 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
569 if (ret != csize)
570 return -1;
571 if (decompress_buffer(s->cluster_cache, s->cluster_size,
572 s->cluster_data, csize) < 0) {
573 return -1;
574 }
575 s->cluster_cache_offset = coffset;
576 }
577 return 0;
578 }
579
580 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
581 int nb_sectors, QEMUIOVector *qiov)
582 {
583 BDRVQcowState *s = bs->opaque;
584 int index_in_cluster;
585 int ret = 0, n;
586 uint64_t cluster_offset;
587 struct iovec hd_iov;
588 QEMUIOVector hd_qiov;
589 uint8_t *buf;
590 void *orig_buf;
591 Error *err = NULL;
592
593 if (qiov->niov > 1) {
594 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
595 if (buf == NULL) {
596 return -ENOMEM;
597 }
598 } else {
599 orig_buf = NULL;
600 buf = (uint8_t *)qiov->iov->iov_base;
601 }
602
603 qemu_co_mutex_lock(&s->lock);
604
605 while (nb_sectors != 0) {
606 /* prepare next request */
607 cluster_offset = get_cluster_offset(bs, sector_num << 9,
608 0, 0, 0, 0);
609 index_in_cluster = sector_num & (s->cluster_sectors - 1);
610 n = s->cluster_sectors - index_in_cluster;
611 if (n > nb_sectors) {
612 n = nb_sectors;
613 }
614
615 if (!cluster_offset) {
616 if (bs->backing) {
617 /* read from the base image */
618 hd_iov.iov_base = (void *)buf;
619 hd_iov.iov_len = n * 512;
620 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
621 qemu_co_mutex_unlock(&s->lock);
622 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov);
623 qemu_co_mutex_lock(&s->lock);
624 if (ret < 0) {
625 goto fail;
626 }
627 } else {
628 /* Note: in this case, no need to wait */
629 memset(buf, 0, 512 * n);
630 }
631 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
632 /* add AIO support for compressed blocks ? */
633 if (decompress_cluster(bs, cluster_offset) < 0) {
634 goto fail;
635 }
636 memcpy(buf,
637 s->cluster_cache + index_in_cluster * 512, 512 * n);
638 } else {
639 if ((cluster_offset & 511) != 0) {
640 goto fail;
641 }
642 hd_iov.iov_base = (void *)buf;
643 hd_iov.iov_len = n * 512;
644 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
645 qemu_co_mutex_unlock(&s->lock);
646 ret = bdrv_co_readv(bs->file,
647 (cluster_offset >> 9) + index_in_cluster,
648 n, &hd_qiov);
649 qemu_co_mutex_lock(&s->lock);
650 if (ret < 0) {
651 break;
652 }
653 if (bs->encrypted) {
654 assert(s->cipher);
655 if (encrypt_sectors(s, sector_num, buf, buf,
656 n, false, &err) < 0) {
657 goto fail;
658 }
659 }
660 }
661 ret = 0;
662
663 nb_sectors -= n;
664 sector_num += n;
665 buf += n * 512;
666 }
667
668 done:
669 qemu_co_mutex_unlock(&s->lock);
670
671 if (qiov->niov > 1) {
672 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
673 qemu_vfree(orig_buf);
674 }
675
676 return ret;
677
678 fail:
679 error_free(err);
680 ret = -EIO;
681 goto done;
682 }
683
684 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
685 int nb_sectors, QEMUIOVector *qiov)
686 {
687 BDRVQcowState *s = bs->opaque;
688 int index_in_cluster;
689 uint64_t cluster_offset;
690 const uint8_t *src_buf;
691 int ret = 0, n;
692 uint8_t *cluster_data = NULL;
693 struct iovec hd_iov;
694 QEMUIOVector hd_qiov;
695 uint8_t *buf;
696 void *orig_buf;
697
698 s->cluster_cache_offset = -1; /* disable compressed cache */
699
700 if (qiov->niov > 1) {
701 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
702 if (buf == NULL) {
703 return -ENOMEM;
704 }
705 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
706 } else {
707 orig_buf = NULL;
708 buf = (uint8_t *)qiov->iov->iov_base;
709 }
710
711 qemu_co_mutex_lock(&s->lock);
712
713 while (nb_sectors != 0) {
714
715 index_in_cluster = sector_num & (s->cluster_sectors - 1);
716 n = s->cluster_sectors - index_in_cluster;
717 if (n > nb_sectors) {
718 n = nb_sectors;
719 }
720 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
721 index_in_cluster,
722 index_in_cluster + n);
723 if (!cluster_offset || (cluster_offset & 511) != 0) {
724 ret = -EIO;
725 break;
726 }
727 if (bs->encrypted) {
728 Error *err = NULL;
729 assert(s->cipher);
730 if (!cluster_data) {
731 cluster_data = g_malloc0(s->cluster_size);
732 }
733 if (encrypt_sectors(s, sector_num, cluster_data, buf,
734 n, true, &err) < 0) {
735 error_free(err);
736 ret = -EIO;
737 break;
738 }
739 src_buf = cluster_data;
740 } else {
741 src_buf = buf;
742 }
743
744 hd_iov.iov_base = (void *)src_buf;
745 hd_iov.iov_len = n * 512;
746 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
747 qemu_co_mutex_unlock(&s->lock);
748 ret = bdrv_co_writev(bs->file,
749 (cluster_offset >> 9) + index_in_cluster,
750 n, &hd_qiov);
751 qemu_co_mutex_lock(&s->lock);
752 if (ret < 0) {
753 break;
754 }
755 ret = 0;
756
757 nb_sectors -= n;
758 sector_num += n;
759 buf += n * 512;
760 }
761 qemu_co_mutex_unlock(&s->lock);
762
763 if (qiov->niov > 1) {
764 qemu_vfree(orig_buf);
765 }
766 g_free(cluster_data);
767
768 return ret;
769 }
770
771 static void qcow_close(BlockDriverState *bs)
772 {
773 BDRVQcowState *s = bs->opaque;
774
775 qcrypto_cipher_free(s->cipher);
776 s->cipher = NULL;
777 g_free(s->l1_table);
778 qemu_vfree(s->l2_cache);
779 g_free(s->cluster_cache);
780 g_free(s->cluster_data);
781
782 migrate_del_blocker(s->migration_blocker);
783 error_free(s->migration_blocker);
784 }
785
786 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
787 {
788 int header_size, backing_filename_len, l1_size, shift, i;
789 QCowHeader header;
790 uint8_t *tmp;
791 int64_t total_size = 0;
792 char *backing_file = NULL;
793 int flags = 0;
794 Error *local_err = NULL;
795 int ret;
796 BlockBackend *qcow_blk;
797
798 /* Read out options */
799 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
800 BDRV_SECTOR_SIZE);
801 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
802 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
803 flags |= BLOCK_FLAG_ENCRYPT;
804 }
805
806 ret = bdrv_create_file(filename, opts, &local_err);
807 if (ret < 0) {
808 error_propagate(errp, local_err);
809 goto cleanup;
810 }
811
812 qcow_blk = blk_new_open(filename, NULL, NULL,
813 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
814 if (qcow_blk == NULL) {
815 error_propagate(errp, local_err);
816 ret = -EIO;
817 goto cleanup;
818 }
819
820 blk_set_allow_write_beyond_eof(qcow_blk, true);
821
822 ret = blk_truncate(qcow_blk, 0);
823 if (ret < 0) {
824 goto exit;
825 }
826
827 memset(&header, 0, sizeof(header));
828 header.magic = cpu_to_be32(QCOW_MAGIC);
829 header.version = cpu_to_be32(QCOW_VERSION);
830 header.size = cpu_to_be64(total_size);
831 header_size = sizeof(header);
832 backing_filename_len = 0;
833 if (backing_file) {
834 if (strcmp(backing_file, "fat:")) {
835 header.backing_file_offset = cpu_to_be64(header_size);
836 backing_filename_len = strlen(backing_file);
837 header.backing_file_size = cpu_to_be32(backing_filename_len);
838 header_size += backing_filename_len;
839 } else {
840 /* special backing file for vvfat */
841 backing_file = NULL;
842 }
843 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
844 unmodified sectors */
845 header.l2_bits = 12; /* 32 KB L2 tables */
846 } else {
847 header.cluster_bits = 12; /* 4 KB clusters */
848 header.l2_bits = 9; /* 4 KB L2 tables */
849 }
850 header_size = (header_size + 7) & ~7;
851 shift = header.cluster_bits + header.l2_bits;
852 l1_size = (total_size + (1LL << shift) - 1) >> shift;
853
854 header.l1_table_offset = cpu_to_be64(header_size);
855 if (flags & BLOCK_FLAG_ENCRYPT) {
856 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
857 } else {
858 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
859 }
860
861 /* write all the data */
862 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0);
863 if (ret != sizeof(header)) {
864 goto exit;
865 }
866
867 if (backing_file) {
868 ret = blk_pwrite(qcow_blk, sizeof(header),
869 backing_file, backing_filename_len, 0);
870 if (ret != backing_filename_len) {
871 goto exit;
872 }
873 }
874
875 tmp = g_malloc0(BDRV_SECTOR_SIZE);
876 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
877 i++) {
878 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
879 tmp, BDRV_SECTOR_SIZE, 0);
880 if (ret != BDRV_SECTOR_SIZE) {
881 g_free(tmp);
882 goto exit;
883 }
884 }
885
886 g_free(tmp);
887 ret = 0;
888 exit:
889 blk_unref(qcow_blk);
890 cleanup:
891 g_free(backing_file);
892 return ret;
893 }
894
895 static int qcow_make_empty(BlockDriverState *bs)
896 {
897 BDRVQcowState *s = bs->opaque;
898 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
899 int ret;
900
901 memset(s->l1_table, 0, l1_length);
902 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
903 l1_length) < 0)
904 return -1;
905 ret = bdrv_truncate(bs->file->bs, s->l1_table_offset + l1_length);
906 if (ret < 0)
907 return ret;
908
909 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
910 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
911 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
912
913 return 0;
914 }
915
916 typedef struct QcowWriteCo {
917 BlockDriverState *bs;
918 int64_t sector_num;
919 const uint8_t *buf;
920 int nb_sectors;
921 int ret;
922 } QcowWriteCo;
923
924 static void qcow_write_co_entry(void *opaque)
925 {
926 QcowWriteCo *co = opaque;
927 QEMUIOVector qiov;
928
929 struct iovec iov = (struct iovec) {
930 .iov_base = (uint8_t*) co->buf,
931 .iov_len = co->nb_sectors * BDRV_SECTOR_SIZE,
932 };
933 qemu_iovec_init_external(&qiov, &iov, 1);
934
935 co->ret = qcow_co_writev(co->bs, co->sector_num, co->nb_sectors, &qiov);
936 }
937
938 /* Wrapper for non-coroutine contexts */
939 static int qcow_write(BlockDriverState *bs, int64_t sector_num,
940 const uint8_t *buf, int nb_sectors)
941 {
942 Coroutine *co;
943 AioContext *aio_context = bdrv_get_aio_context(bs);
944 QcowWriteCo data = {
945 .bs = bs,
946 .sector_num = sector_num,
947 .buf = buf,
948 .nb_sectors = nb_sectors,
949 .ret = -EINPROGRESS,
950 };
951 co = qemu_coroutine_create(qcow_write_co_entry, &data);
952 qemu_coroutine_enter(co);
953 while (data.ret == -EINPROGRESS) {
954 aio_poll(aio_context, true);
955 }
956 return data.ret;
957 }
958
959 /* XXX: put compressed sectors first, then all the cluster aligned
960 tables to avoid losing bytes in alignment */
961 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
962 const uint8_t *buf, int nb_sectors)
963 {
964 BDRVQcowState *s = bs->opaque;
965 z_stream strm;
966 int ret, out_len;
967 uint8_t *out_buf;
968 uint64_t cluster_offset;
969
970 if (nb_sectors != s->cluster_sectors) {
971 ret = -EINVAL;
972
973 /* Zero-pad last write if image size is not cluster aligned */
974 if (sector_num + nb_sectors == bs->total_sectors &&
975 nb_sectors < s->cluster_sectors) {
976 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
977 memset(pad_buf, 0, s->cluster_size);
978 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
979 ret = qcow_write_compressed(bs, sector_num,
980 pad_buf, s->cluster_sectors);
981 qemu_vfree(pad_buf);
982 }
983 return ret;
984 }
985
986 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
987
988 /* best compression, small window, no zlib header */
989 memset(&strm, 0, sizeof(strm));
990 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
991 Z_DEFLATED, -12,
992 9, Z_DEFAULT_STRATEGY);
993 if (ret != 0) {
994 ret = -EINVAL;
995 goto fail;
996 }
997
998 strm.avail_in = s->cluster_size;
999 strm.next_in = (uint8_t *)buf;
1000 strm.avail_out = s->cluster_size;
1001 strm.next_out = out_buf;
1002
1003 ret = deflate(&strm, Z_FINISH);
1004 if (ret != Z_STREAM_END && ret != Z_OK) {
1005 deflateEnd(&strm);
1006 ret = -EINVAL;
1007 goto fail;
1008 }
1009 out_len = strm.next_out - out_buf;
1010
1011 deflateEnd(&strm);
1012
1013 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1014 /* could not compress: write normal cluster */
1015 ret = qcow_write(bs, sector_num, buf, s->cluster_sectors);
1016 if (ret < 0) {
1017 goto fail;
1018 }
1019 } else {
1020 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
1021 out_len, 0, 0);
1022 if (cluster_offset == 0) {
1023 ret = -EIO;
1024 goto fail;
1025 }
1026
1027 cluster_offset &= s->cluster_offset_mask;
1028 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
1029 if (ret < 0) {
1030 goto fail;
1031 }
1032 }
1033
1034 ret = 0;
1035 fail:
1036 g_free(out_buf);
1037 return ret;
1038 }
1039
1040 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1041 {
1042 BDRVQcowState *s = bs->opaque;
1043 bdi->cluster_size = s->cluster_size;
1044 return 0;
1045 }
1046
1047 static QemuOptsList qcow_create_opts = {
1048 .name = "qcow-create-opts",
1049 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1050 .desc = {
1051 {
1052 .name = BLOCK_OPT_SIZE,
1053 .type = QEMU_OPT_SIZE,
1054 .help = "Virtual disk size"
1055 },
1056 {
1057 .name = BLOCK_OPT_BACKING_FILE,
1058 .type = QEMU_OPT_STRING,
1059 .help = "File name of a base image"
1060 },
1061 {
1062 .name = BLOCK_OPT_ENCRYPT,
1063 .type = QEMU_OPT_BOOL,
1064 .help = "Encrypt the image",
1065 .def_value_str = "off"
1066 },
1067 { /* end of list */ }
1068 }
1069 };
1070
1071 static BlockDriver bdrv_qcow = {
1072 .format_name = "qcow",
1073 .instance_size = sizeof(BDRVQcowState),
1074 .bdrv_probe = qcow_probe,
1075 .bdrv_open = qcow_open,
1076 .bdrv_close = qcow_close,
1077 .bdrv_reopen_prepare = qcow_reopen_prepare,
1078 .bdrv_create = qcow_create,
1079 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1080 .supports_backing = true,
1081
1082 .bdrv_co_readv = qcow_co_readv,
1083 .bdrv_co_writev = qcow_co_writev,
1084 .bdrv_co_get_block_status = qcow_co_get_block_status,
1085
1086 .bdrv_set_key = qcow_set_key,
1087 .bdrv_make_empty = qcow_make_empty,
1088 .bdrv_write_compressed = qcow_write_compressed,
1089 .bdrv_get_info = qcow_get_info,
1090
1091 .create_opts = &qcow_create_opts,
1092 };
1093
1094 static void bdrv_qcow_init(void)
1095 {
1096 bdrv_register(&bdrv_qcow);
1097 }
1098
1099 block_init(bdrv_qcow_init);
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