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block/iscsi: use the allocationmap also if cache.direct=on
[qemu/cris-port.git] / block / qcow.c
blobab893284d24b586b6e5f381cbd55714231b718ed
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-common.h"
25 #include "block/block_int.h"
26 #include "qemu/module.h"
27 #include <zlib.h>
28 #include "qemu/aes.h"
29 #include "migration/migration.h"
30
31 /**************************************************************/
32 /* QEMU COW block driver with compression and encryption support */
33
34 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
35 #define QCOW_VERSION 1
36
37 #define QCOW_CRYPT_NONE 0
38 #define QCOW_CRYPT_AES 1
39
40 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
41
42 typedef struct QCowHeader {
43 uint32_t magic;
44 uint32_t version;
45 uint64_t backing_file_offset;
46 uint32_t backing_file_size;
47 uint32_t mtime;
48 uint64_t size; /* in bytes */
49 uint8_t cluster_bits;
50 uint8_t l2_bits;
51 uint16_t padding;
52 uint32_t crypt_method;
53 uint64_t l1_table_offset;
54 } QEMU_PACKED QCowHeader;
55
56 #define L2_CACHE_SIZE 16
57
58 typedef struct BDRVQcowState {
59 int cluster_bits;
60 int cluster_size;
61 int cluster_sectors;
62 int l2_bits;
63 int l2_size;
64 unsigned int l1_size;
65 uint64_t cluster_offset_mask;
66 uint64_t l1_table_offset;
67 uint64_t *l1_table;
68 uint64_t *l2_cache;
69 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
70 uint32_t l2_cache_counts[L2_CACHE_SIZE];
71 uint8_t *cluster_cache;
72 uint8_t *cluster_data;
73 uint64_t cluster_cache_offset;
74 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
75 uint32_t crypt_method_header;
76 AES_KEY aes_encrypt_key;
77 AES_KEY aes_decrypt_key;
78 CoMutex lock;
79 Error *migration_blocker;
80 } BDRVQcowState;
81
82 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
83
84 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
85 {
86 const QCowHeader *cow_header = (const void *)buf;
87
88 if (buf_size >= sizeof(QCowHeader) &&
89 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
90 be32_to_cpu(cow_header->version) == QCOW_VERSION)
91 return 100;
92 else
93 return 0;
94 }
95
96 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
97 Error **errp)
98 {
99 BDRVQcowState *s = bs->opaque;
100 unsigned int len, i, shift;
101 int ret;
102 QCowHeader header;
103
104 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
105 if (ret < 0) {
106 goto fail;
107 }
108 be32_to_cpus(&header.magic);
109 be32_to_cpus(&header.version);
110 be64_to_cpus(&header.backing_file_offset);
111 be32_to_cpus(&header.backing_file_size);
112 be32_to_cpus(&header.mtime);
113 be64_to_cpus(&header.size);
114 be32_to_cpus(&header.crypt_method);
115 be64_to_cpus(&header.l1_table_offset);
116
117 if (header.magic != QCOW_MAGIC) {
118 error_setg(errp, "Image not in qcow format");
119 ret = -EINVAL;
120 goto fail;
121 }
122 if (header.version != QCOW_VERSION) {
123 char version[64];
124 snprintf(version, sizeof(version), "QCOW version %" PRIu32,
125 header.version);
126 error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
127 bdrv_get_device_or_node_name(bs), "qcow", 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 s->crypt_method_header = header.crypt_method;
157 if (s->crypt_method_header) {
158 bs->encrypted = 1;
159 }
160 s->cluster_bits = header.cluster_bits;
161 s->cluster_size = 1 << s->cluster_bits;
162 s->cluster_sectors = 1 << (s->cluster_bits - 9);
163 s->l2_bits = header.l2_bits;
164 s->l2_size = 1 << s->l2_bits;
165 bs->total_sectors = header.size / 512;
166 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
167
168 /* read the level 1 table */
169 shift = s->cluster_bits + s->l2_bits;
170 if (header.size > UINT64_MAX - (1LL << shift)) {
171 error_setg(errp, "Image too large");
172 ret = -EINVAL;
173 goto fail;
174 } else {
175 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
176 if (l1_size > INT_MAX / sizeof(uint64_t)) {
177 error_setg(errp, "Image too large");
178 ret = -EINVAL;
179 goto fail;
180 }
181 s->l1_size = l1_size;
182 }
183
184 s->l1_table_offset = header.l1_table_offset;
185 s->l1_table = g_try_new(uint64_t, s->l1_size);
186 if (s->l1_table == NULL) {
187 error_setg(errp, "Could not allocate memory for L1 table");
188 ret = -ENOMEM;
189 goto fail;
190 }
191
192 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
193 s->l1_size * sizeof(uint64_t));
194 if (ret < 0) {
195 goto fail;
196 }
197
198 for(i = 0;i < s->l1_size; i++) {
199 be64_to_cpus(&s->l1_table[i]);
200 }
201
202 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
203 s->l2_cache =
204 qemu_try_blockalign(bs->file,
205 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
206 if (s->l2_cache == NULL) {
207 error_setg(errp, "Could not allocate L2 table cache");
208 ret = -ENOMEM;
209 goto fail;
210 }
211 s->cluster_cache = g_malloc(s->cluster_size);
212 s->cluster_data = g_malloc(s->cluster_size);
213 s->cluster_cache_offset = -1;
214
215 /* read the backing file name */
216 if (header.backing_file_offset != 0) {
217 len = header.backing_file_size;
218 if (len > 1023 || len >= sizeof(bs->backing_file)) {
219 error_setg(errp, "Backing file name too long");
220 ret = -EINVAL;
221 goto fail;
222 }
223 ret = bdrv_pread(bs->file, header.backing_file_offset,
224 bs->backing_file, len);
225 if (ret < 0) {
226 goto fail;
227 }
228 bs->backing_file[len] = '\0';
229 }
230
231 /* Disable migration when qcow images are used */
232 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
233 "does not support live migration",
234 bdrv_get_device_or_node_name(bs));
235 migrate_add_blocker(s->migration_blocker);
236
237 qemu_co_mutex_init(&s->lock);
238 return 0;
239
240 fail:
241 g_free(s->l1_table);
242 qemu_vfree(s->l2_cache);
243 g_free(s->cluster_cache);
244 g_free(s->cluster_data);
245 return ret;
246 }
247
248
249 /* We have nothing to do for QCOW reopen, stubs just return
250 * success */
251 static int qcow_reopen_prepare(BDRVReopenState *state,
252 BlockReopenQueue *queue, Error **errp)
253 {
254 return 0;
255 }
256
257 static int qcow_set_key(BlockDriverState *bs, const char *key)
258 {
259 BDRVQcowState *s = bs->opaque;
260 uint8_t keybuf[16];
261 int len, i;
262
263 memset(keybuf, 0, 16);
264 len = strlen(key);
265 if (len > 16)
266 len = 16;
267 /* XXX: we could compress the chars to 7 bits to increase
268 entropy */
269 for(i = 0;i < len;i++) {
270 keybuf[i] = key[i];
271 }
272 s->crypt_method = s->crypt_method_header;
273
274 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
275 return -1;
276 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
277 return -1;
278 return 0;
279 }
280
281 /* The crypt function is compatible with the linux cryptoloop
282 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
283 supported */
284 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
285 uint8_t *out_buf, const uint8_t *in_buf,
286 int nb_sectors, int enc,
287 const AES_KEY *key)
288 {
289 union {
290 uint64_t ll[2];
291 uint8_t b[16];
292 } ivec;
293 int i;
294
295 for(i = 0; i < nb_sectors; i++) {
296 ivec.ll[0] = cpu_to_le64(sector_num);
297 ivec.ll[1] = 0;
298 AES_cbc_encrypt(in_buf, out_buf, 512, key,
299 ivec.b, enc);
300 sector_num++;
301 in_buf += 512;
302 out_buf += 512;
303 }
304 }
305
306 /* 'allocate' is:
307 *
308 * 0 to not allocate.
309 *
310 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
311 * 'n_end')
312 *
313 * 2 to allocate a compressed cluster of size
314 * 'compressed_size'. 'compressed_size' must be > 0 and <
315 * cluster_size
316 *
317 * return 0 if not allocated.
318 */
319 static uint64_t get_cluster_offset(BlockDriverState *bs,
320 uint64_t offset, int allocate,
321 int compressed_size,
322 int n_start, int n_end)
323 {
324 BDRVQcowState *s = bs->opaque;
325 int min_index, i, j, l1_index, l2_index;
326 uint64_t l2_offset, *l2_table, cluster_offset, tmp;
327 uint32_t min_count;
328 int new_l2_table;
329
330 l1_index = offset >> (s->l2_bits + s->cluster_bits);
331 l2_offset = s->l1_table[l1_index];
332 new_l2_table = 0;
333 if (!l2_offset) {
334 if (!allocate)
335 return 0;
336 /* allocate a new l2 entry */
337 l2_offset = bdrv_getlength(bs->file);
338 /* round to cluster size */
339 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
340 /* update the L1 entry */
341 s->l1_table[l1_index] = l2_offset;
342 tmp = cpu_to_be64(l2_offset);
343 if (bdrv_pwrite_sync(bs->file,
344 s->l1_table_offset + l1_index * sizeof(tmp),
345 &tmp, sizeof(tmp)) < 0)
346 return 0;
347 new_l2_table = 1;
348 }
349 for(i = 0; i < L2_CACHE_SIZE; i++) {
350 if (l2_offset == s->l2_cache_offsets[i]) {
351 /* increment the hit count */
352 if (++s->l2_cache_counts[i] == 0xffffffff) {
353 for(j = 0; j < L2_CACHE_SIZE; j++) {
354 s->l2_cache_counts[j] >>= 1;
355 }
356 }
357 l2_table = s->l2_cache + (i << s->l2_bits);
358 goto found;
359 }
360 }
361 /* not found: load a new entry in the least used one */
362 min_index = 0;
363 min_count = 0xffffffff;
364 for(i = 0; i < L2_CACHE_SIZE; i++) {
365 if (s->l2_cache_counts[i] < min_count) {
366 min_count = s->l2_cache_counts[i];
367 min_index = i;
368 }
369 }
370 l2_table = s->l2_cache + (min_index << s->l2_bits);
371 if (new_l2_table) {
372 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
373 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
374 s->l2_size * sizeof(uint64_t)) < 0)
375 return 0;
376 } else {
377 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
378 s->l2_size * sizeof(uint64_t))
379 return 0;
380 }
381 s->l2_cache_offsets[min_index] = l2_offset;
382 s->l2_cache_counts[min_index] = 1;
383 found:
384 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
385 cluster_offset = be64_to_cpu(l2_table[l2_index]);
386 if (!cluster_offset ||
387 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
388 if (!allocate)
389 return 0;
390 /* allocate a new cluster */
391 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
392 (n_end - n_start) < s->cluster_sectors) {
393 /* if the cluster is already compressed, we must
394 decompress it in the case it is not completely
395 overwritten */
396 if (decompress_cluster(bs, cluster_offset) < 0)
397 return 0;
398 cluster_offset = bdrv_getlength(bs->file);
399 cluster_offset = (cluster_offset + s->cluster_size - 1) &
400 ~(s->cluster_size - 1);
401 /* write the cluster content */
402 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
403 s->cluster_size)
404 return -1;
405 } else {
406 cluster_offset = bdrv_getlength(bs->file);
407 if (allocate == 1) {
408 /* round to cluster size */
409 cluster_offset = (cluster_offset + s->cluster_size - 1) &
410 ~(s->cluster_size - 1);
411 bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
412 /* if encrypted, we must initialize the cluster
413 content which won't be written */
414 if (s->crypt_method &&
415 (n_end - n_start) < s->cluster_sectors) {
416 uint64_t start_sect;
417 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
418 memset(s->cluster_data + 512, 0x00, 512);
419 for(i = 0; i < s->cluster_sectors; i++) {
420 if (i < n_start || i >= n_end) {
421 encrypt_sectors(s, start_sect + i,
422 s->cluster_data,
423 s->cluster_data + 512, 1, 1,
424 &s->aes_encrypt_key);
425 if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
426 s->cluster_data, 512) != 512)
427 return -1;
428 }
429 }
430 }
431 } else if (allocate == 2) {
432 cluster_offset |= QCOW_OFLAG_COMPRESSED |
433 (uint64_t)compressed_size << (63 - s->cluster_bits);
434 }
435 }
436 /* update L2 table */
437 tmp = cpu_to_be64(cluster_offset);
438 l2_table[l2_index] = tmp;
439 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
440 &tmp, sizeof(tmp)) < 0)
441 return 0;
442 }
443 return cluster_offset;
444 }
445
446 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
447 int64_t sector_num, int nb_sectors, int *pnum)
448 {
449 BDRVQcowState *s = bs->opaque;
450 int index_in_cluster, n;
451 uint64_t cluster_offset;
452
453 qemu_co_mutex_lock(&s->lock);
454 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
455 qemu_co_mutex_unlock(&s->lock);
456 index_in_cluster = sector_num & (s->cluster_sectors - 1);
457 n = s->cluster_sectors - index_in_cluster;
458 if (n > nb_sectors)
459 n = nb_sectors;
460 *pnum = n;
461 if (!cluster_offset) {
462 return 0;
463 }
464 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) {
465 return BDRV_BLOCK_DATA;
466 }
467 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
468 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset;
469 }
470
471 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
472 const uint8_t *buf, int buf_size)
473 {
474 z_stream strm1, *strm = &strm1;
475 int ret, out_len;
476
477 memset(strm, 0, sizeof(*strm));
478
479 strm->next_in = (uint8_t *)buf;
480 strm->avail_in = buf_size;
481 strm->next_out = out_buf;
482 strm->avail_out = out_buf_size;
483
484 ret = inflateInit2(strm, -12);
485 if (ret != Z_OK)
486 return -1;
487 ret = inflate(strm, Z_FINISH);
488 out_len = strm->next_out - out_buf;
489 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
490 out_len != out_buf_size) {
491 inflateEnd(strm);
492 return -1;
493 }
494 inflateEnd(strm);
495 return 0;
496 }
497
498 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
499 {
500 BDRVQcowState *s = bs->opaque;
501 int ret, csize;
502 uint64_t coffset;
503
504 coffset = cluster_offset & s->cluster_offset_mask;
505 if (s->cluster_cache_offset != coffset) {
506 csize = cluster_offset >> (63 - s->cluster_bits);
507 csize &= (s->cluster_size - 1);
508 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
509 if (ret != csize)
510 return -1;
511 if (decompress_buffer(s->cluster_cache, s->cluster_size,
512 s->cluster_data, csize) < 0) {
513 return -1;
514 }
515 s->cluster_cache_offset = coffset;
516 }
517 return 0;
518 }
519
520 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
521 int nb_sectors, QEMUIOVector *qiov)
522 {
523 BDRVQcowState *s = bs->opaque;
524 int index_in_cluster;
525 int ret = 0, n;
526 uint64_t cluster_offset;
527 struct iovec hd_iov;
528 QEMUIOVector hd_qiov;
529 uint8_t *buf;
530 void *orig_buf;
531
532 if (qiov->niov > 1) {
533 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
534 if (buf == NULL) {
535 return -ENOMEM;
536 }
537 } else {
538 orig_buf = NULL;
539 buf = (uint8_t *)qiov->iov->iov_base;
540 }
541
542 qemu_co_mutex_lock(&s->lock);
543
544 while (nb_sectors != 0) {
545 /* prepare next request */
546 cluster_offset = get_cluster_offset(bs, sector_num << 9,
547 0, 0, 0, 0);
548 index_in_cluster = sector_num & (s->cluster_sectors - 1);
549 n = s->cluster_sectors - index_in_cluster;
550 if (n > nb_sectors) {
551 n = nb_sectors;
552 }
553
554 if (!cluster_offset) {
555 if (bs->backing_hd) {
556 /* read from the base image */
557 hd_iov.iov_base = (void *)buf;
558 hd_iov.iov_len = n * 512;
559 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
560 qemu_co_mutex_unlock(&s->lock);
561 ret = bdrv_co_readv(bs->backing_hd, sector_num,
562 n, &hd_qiov);
563 qemu_co_mutex_lock(&s->lock);
564 if (ret < 0) {
565 goto fail;
566 }
567 } else {
568 /* Note: in this case, no need to wait */
569 memset(buf, 0, 512 * n);
570 }
571 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
572 /* add AIO support for compressed blocks ? */
573 if (decompress_cluster(bs, cluster_offset) < 0) {
574 goto fail;
575 }
576 memcpy(buf,
577 s->cluster_cache + index_in_cluster * 512, 512 * n);
578 } else {
579 if ((cluster_offset & 511) != 0) {
580 goto fail;
581 }
582 hd_iov.iov_base = (void *)buf;
583 hd_iov.iov_len = n * 512;
584 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
585 qemu_co_mutex_unlock(&s->lock);
586 ret = bdrv_co_readv(bs->file,
587 (cluster_offset >> 9) + index_in_cluster,
588 n, &hd_qiov);
589 qemu_co_mutex_lock(&s->lock);
590 if (ret < 0) {
591 break;
592 }
593 if (s->crypt_method) {
594 encrypt_sectors(s, sector_num, buf, buf,
595 n, 0,
596 &s->aes_decrypt_key);
597 }
598 }
599 ret = 0;
600
601 nb_sectors -= n;
602 sector_num += n;
603 buf += n * 512;
604 }
605
606 done:
607 qemu_co_mutex_unlock(&s->lock);
608
609 if (qiov->niov > 1) {
610 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
611 qemu_vfree(orig_buf);
612 }
613
614 return ret;
615
616 fail:
617 ret = -EIO;
618 goto done;
619 }
620
621 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
622 int nb_sectors, QEMUIOVector *qiov)
623 {
624 BDRVQcowState *s = bs->opaque;
625 int index_in_cluster;
626 uint64_t cluster_offset;
627 const uint8_t *src_buf;
628 int ret = 0, n;
629 uint8_t *cluster_data = NULL;
630 struct iovec hd_iov;
631 QEMUIOVector hd_qiov;
632 uint8_t *buf;
633 void *orig_buf;
634
635 s->cluster_cache_offset = -1; /* disable compressed cache */
636
637 if (qiov->niov > 1) {
638 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
639 if (buf == NULL) {
640 return -ENOMEM;
641 }
642 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
643 } else {
644 orig_buf = NULL;
645 buf = (uint8_t *)qiov->iov->iov_base;
646 }
647
648 qemu_co_mutex_lock(&s->lock);
649
650 while (nb_sectors != 0) {
651
652 index_in_cluster = sector_num & (s->cluster_sectors - 1);
653 n = s->cluster_sectors - index_in_cluster;
654 if (n > nb_sectors) {
655 n = nb_sectors;
656 }
657 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
658 index_in_cluster,
659 index_in_cluster + n);
660 if (!cluster_offset || (cluster_offset & 511) != 0) {
661 ret = -EIO;
662 break;
663 }
664 if (s->crypt_method) {
665 if (!cluster_data) {
666 cluster_data = g_malloc0(s->cluster_size);
667 }
668 encrypt_sectors(s, sector_num, cluster_data, buf,
669 n, 1, &s->aes_encrypt_key);
670 src_buf = cluster_data;
671 } else {
672 src_buf = buf;
673 }
674
675 hd_iov.iov_base = (void *)src_buf;
676 hd_iov.iov_len = n * 512;
677 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
678 qemu_co_mutex_unlock(&s->lock);
679 ret = bdrv_co_writev(bs->file,
680 (cluster_offset >> 9) + index_in_cluster,
681 n, &hd_qiov);
682 qemu_co_mutex_lock(&s->lock);
683 if (ret < 0) {
684 break;
685 }
686 ret = 0;
687
688 nb_sectors -= n;
689 sector_num += n;
690 buf += n * 512;
691 }
692 qemu_co_mutex_unlock(&s->lock);
693
694 if (qiov->niov > 1) {
695 qemu_vfree(orig_buf);
696 }
697 g_free(cluster_data);
698
699 return ret;
700 }
701
702 static void qcow_close(BlockDriverState *bs)
703 {
704 BDRVQcowState *s = bs->opaque;
705
706 g_free(s->l1_table);
707 qemu_vfree(s->l2_cache);
708 g_free(s->cluster_cache);
709 g_free(s->cluster_data);
710
711 migrate_del_blocker(s->migration_blocker);
712 error_free(s->migration_blocker);
713 }
714
715 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
716 {
717 int header_size, backing_filename_len, l1_size, shift, i;
718 QCowHeader header;
719 uint8_t *tmp;
720 int64_t total_size = 0;
721 char *backing_file = NULL;
722 int flags = 0;
723 Error *local_err = NULL;
724 int ret;
725 BlockDriverState *qcow_bs;
726
727 /* Read out options */
728 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
729 BDRV_SECTOR_SIZE);
730 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
731 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
732 flags |= BLOCK_FLAG_ENCRYPT;
733 }
734
735 ret = bdrv_create_file(filename, opts, &local_err);
736 if (ret < 0) {
737 error_propagate(errp, local_err);
738 goto cleanup;
739 }
740
741 qcow_bs = NULL;
742 ret = bdrv_open(&qcow_bs, filename, NULL, NULL,
743 BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err);
744 if (ret < 0) {
745 error_propagate(errp, local_err);
746 goto cleanup;
747 }
748
749 ret = bdrv_truncate(qcow_bs, 0);
750 if (ret < 0) {
751 goto exit;
752 }
753
754 memset(&header, 0, sizeof(header));
755 header.magic = cpu_to_be32(QCOW_MAGIC);
756 header.version = cpu_to_be32(QCOW_VERSION);
757 header.size = cpu_to_be64(total_size);
758 header_size = sizeof(header);
759 backing_filename_len = 0;
760 if (backing_file) {
761 if (strcmp(backing_file, "fat:")) {
762 header.backing_file_offset = cpu_to_be64(header_size);
763 backing_filename_len = strlen(backing_file);
764 header.backing_file_size = cpu_to_be32(backing_filename_len);
765 header_size += backing_filename_len;
766 } else {
767 /* special backing file for vvfat */
768 backing_file = NULL;
769 }
770 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
771 unmodified sectors */
772 header.l2_bits = 12; /* 32 KB L2 tables */
773 } else {
774 header.cluster_bits = 12; /* 4 KB clusters */
775 header.l2_bits = 9; /* 4 KB L2 tables */
776 }
777 header_size = (header_size + 7) & ~7;
778 shift = header.cluster_bits + header.l2_bits;
779 l1_size = (total_size + (1LL << shift) - 1) >> shift;
780
781 header.l1_table_offset = cpu_to_be64(header_size);
782 if (flags & BLOCK_FLAG_ENCRYPT) {
783 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
784 } else {
785 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
786 }
787
788 /* write all the data */
789 ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header));
790 if (ret != sizeof(header)) {
791 goto exit;
792 }
793
794 if (backing_file) {
795 ret = bdrv_pwrite(qcow_bs, sizeof(header),
796 backing_file, backing_filename_len);
797 if (ret != backing_filename_len) {
798 goto exit;
799 }
800 }
801
802 tmp = g_malloc0(BDRV_SECTOR_SIZE);
803 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/
804 BDRV_SECTOR_SIZE); i++) {
805 ret = bdrv_pwrite(qcow_bs, header_size +
806 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE);
807 if (ret != BDRV_SECTOR_SIZE) {
808 g_free(tmp);
809 goto exit;
810 }
811 }
812
813 g_free(tmp);
814 ret = 0;
815 exit:
816 bdrv_unref(qcow_bs);
817 cleanup:
818 g_free(backing_file);
819 return ret;
820 }
821
822 static int qcow_make_empty(BlockDriverState *bs)
823 {
824 BDRVQcowState *s = bs->opaque;
825 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
826 int ret;
827
828 memset(s->l1_table, 0, l1_length);
829 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
830 l1_length) < 0)
831 return -1;
832 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
833 if (ret < 0)
834 return ret;
835
836 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
837 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
838 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
839
840 return 0;
841 }
842
843 /* XXX: put compressed sectors first, then all the cluster aligned
844 tables to avoid losing bytes in alignment */
845 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
846 const uint8_t *buf, int nb_sectors)
847 {
848 BDRVQcowState *s = bs->opaque;
849 z_stream strm;
850 int ret, out_len;
851 uint8_t *out_buf;
852 uint64_t cluster_offset;
853
854 if (nb_sectors != s->cluster_sectors) {
855 ret = -EINVAL;
856
857 /* Zero-pad last write if image size is not cluster aligned */
858 if (sector_num + nb_sectors == bs->total_sectors &&
859 nb_sectors < s->cluster_sectors) {
860 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
861 memset(pad_buf, 0, s->cluster_size);
862 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
863 ret = qcow_write_compressed(bs, sector_num,
864 pad_buf, s->cluster_sectors);
865 qemu_vfree(pad_buf);
866 }
867 return ret;
868 }
869
870 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
871
872 /* best compression, small window, no zlib header */
873 memset(&strm, 0, sizeof(strm));
874 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
875 Z_DEFLATED, -12,
876 9, Z_DEFAULT_STRATEGY);
877 if (ret != 0) {
878 ret = -EINVAL;
879 goto fail;
880 }
881
882 strm.avail_in = s->cluster_size;
883 strm.next_in = (uint8_t *)buf;
884 strm.avail_out = s->cluster_size;
885 strm.next_out = out_buf;
886
887 ret = deflate(&strm, Z_FINISH);
888 if (ret != Z_STREAM_END && ret != Z_OK) {
889 deflateEnd(&strm);
890 ret = -EINVAL;
891 goto fail;
892 }
893 out_len = strm.next_out - out_buf;
894
895 deflateEnd(&strm);
896
897 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
898 /* could not compress: write normal cluster */
899 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
900 if (ret < 0) {
901 goto fail;
902 }
903 } else {
904 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
905 out_len, 0, 0);
906 if (cluster_offset == 0) {
907 ret = -EIO;
908 goto fail;
909 }
910
911 cluster_offset &= s->cluster_offset_mask;
912 ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
913 if (ret < 0) {
914 goto fail;
915 }
916 }
917
918 ret = 0;
919 fail:
920 g_free(out_buf);
921 return ret;
922 }
923
924 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
925 {
926 BDRVQcowState *s = bs->opaque;
927 bdi->cluster_size = s->cluster_size;
928 return 0;
929 }
930
931 static QemuOptsList qcow_create_opts = {
932 .name = "qcow-create-opts",
933 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
934 .desc = {
935 {
936 .name = BLOCK_OPT_SIZE,
937 .type = QEMU_OPT_SIZE,
938 .help = "Virtual disk size"
939 },
940 {
941 .name = BLOCK_OPT_BACKING_FILE,
942 .type = QEMU_OPT_STRING,
943 .help = "File name of a base image"
944 },
945 {
946 .name = BLOCK_OPT_ENCRYPT,
947 .type = QEMU_OPT_BOOL,
948 .help = "Encrypt the image",
949 .def_value_str = "off"
950 },
951 { /* end of list */ }
952 }
953 };
954
955 static BlockDriver bdrv_qcow = {
956 .format_name = "qcow",
957 .instance_size = sizeof(BDRVQcowState),
958 .bdrv_probe = qcow_probe,
959 .bdrv_open = qcow_open,
960 .bdrv_close = qcow_close,
961 .bdrv_reopen_prepare = qcow_reopen_prepare,
962 .bdrv_create = qcow_create,
963 .bdrv_has_zero_init = bdrv_has_zero_init_1,
964 .supports_backing = true,
965
966 .bdrv_co_readv = qcow_co_readv,
967 .bdrv_co_writev = qcow_co_writev,
968 .bdrv_co_get_block_status = qcow_co_get_block_status,
969
970 .bdrv_set_key = qcow_set_key,
971 .bdrv_make_empty = qcow_make_empty,
972 .bdrv_write_compressed = qcow_write_compressed,
973 .bdrv_get_info = qcow_get_info,
974
975 .create_opts = &qcow_create_opts,
976 };
977
978 static void bdrv_qcow_init(void)
979 {
980 bdrv_register(&bdrv_qcow);
981 }
982
983 block_init(bdrv_qcow_init);
CRIS target port of Qemu