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[qemu/ar7.git] / block / qcow.c
blob55a68a698ade76346880b92feb12f0352490829a
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_int.h"
26 #include "module.h"
27 #include <zlib.h>
28 #include "aes.h"
29
30 /**************************************************************/
31 /* QEMU COW block driver with compression and encryption support */
32
33 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
34 #define QCOW_VERSION 1
35
36 #define QCOW_CRYPT_NONE 0
37 #define QCOW_CRYPT_AES 1
38
39 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
40
41 typedef struct QCowHeader {
42 uint32_t magic;
43 uint32_t version;
44 uint64_t backing_file_offset;
45 uint32_t backing_file_size;
46 uint32_t mtime;
47 uint64_t size; /* in bytes */
48 uint8_t cluster_bits;
49 uint8_t l2_bits;
50 uint32_t crypt_method;
51 uint64_t l1_table_offset;
52 } QCowHeader;
53
54 #define L2_CACHE_SIZE 16
55
56 typedef struct BDRVQcowState {
57 BlockDriverState *hd;
58 int cluster_bits;
59 int cluster_size;
60 int cluster_sectors;
61 int l2_bits;
62 int l2_size;
63 int l1_size;
64 uint64_t cluster_offset_mask;
65 uint64_t l1_table_offset;
66 uint64_t *l1_table;
67 uint64_t *l2_cache;
68 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
69 uint32_t l2_cache_counts[L2_CACHE_SIZE];
70 uint8_t *cluster_cache;
71 uint8_t *cluster_data;
72 uint64_t cluster_cache_offset;
73 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
74 uint32_t crypt_method_header;
75 AES_KEY aes_encrypt_key;
76 AES_KEY aes_decrypt_key;
77 } BDRVQcowState;
78
79 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
80
81 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
82 {
83 const QCowHeader *cow_header = (const void *)buf;
84
85 if (buf_size >= sizeof(QCowHeader) &&
86 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
87 be32_to_cpu(cow_header->version) == QCOW_VERSION)
88 return 100;
89 else
90 return 0;
91 }
92
93 static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
94 {
95 BDRVQcowState *s = bs->opaque;
96 int len, i, shift, ret;
97 QCowHeader header;
98
99 ret = bdrv_file_open(&s->hd, filename, flags);
100 if (ret < 0)
101 return ret;
102 if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
103 goto fail;
104 be32_to_cpus(&header.magic);
105 be32_to_cpus(&header.version);
106 be64_to_cpus(&header.backing_file_offset);
107 be32_to_cpus(&header.backing_file_size);
108 be32_to_cpus(&header.mtime);
109 be64_to_cpus(&header.size);
110 be32_to_cpus(&header.crypt_method);
111 be64_to_cpus(&header.l1_table_offset);
112
113 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
114 goto fail;
115 if (header.size <= 1 || header.cluster_bits < 9)
116 goto fail;
117 if (header.crypt_method > QCOW_CRYPT_AES)
118 goto fail;
119 s->crypt_method_header = header.crypt_method;
120 if (s->crypt_method_header)
121 bs->encrypted = 1;
122 s->cluster_bits = header.cluster_bits;
123 s->cluster_size = 1 << s->cluster_bits;
124 s->cluster_sectors = 1 << (s->cluster_bits - 9);
125 s->l2_bits = header.l2_bits;
126 s->l2_size = 1 << s->l2_bits;
127 bs->total_sectors = header.size / 512;
128 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
129
130 /* read the level 1 table */
131 shift = s->cluster_bits + s->l2_bits;
132 s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
133
134 s->l1_table_offset = header.l1_table_offset;
135 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
136 if (!s->l1_table)
137 goto fail;
138 if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
139 s->l1_size * sizeof(uint64_t))
140 goto fail;
141 for(i = 0;i < s->l1_size; i++) {
142 be64_to_cpus(&s->l1_table[i]);
143 }
144 /* alloc L2 cache */
145 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
146 if (!s->l2_cache)
147 goto fail;
148 s->cluster_cache = qemu_malloc(s->cluster_size);
149 if (!s->cluster_cache)
150 goto fail;
151 s->cluster_data = qemu_malloc(s->cluster_size);
152 if (!s->cluster_data)
153 goto fail;
154 s->cluster_cache_offset = -1;
155
156 /* read the backing file name */
157 if (header.backing_file_offset != 0) {
158 len = header.backing_file_size;
159 if (len > 1023)
160 len = 1023;
161 if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
162 goto fail;
163 bs->backing_file[len] = '\0';
164 }
165 return 0;
166
167 fail:
168 qemu_free(s->l1_table);
169 qemu_free(s->l2_cache);
170 qemu_free(s->cluster_cache);
171 qemu_free(s->cluster_data);
172 bdrv_delete(s->hd);
173 return -1;
174 }
175
176 static int qcow_set_key(BlockDriverState *bs, const char *key)
177 {
178 BDRVQcowState *s = bs->opaque;
179 uint8_t keybuf[16];
180 int len, i;
181
182 memset(keybuf, 0, 16);
183 len = strlen(key);
184 if (len > 16)
185 len = 16;
186 /* XXX: we could compress the chars to 7 bits to increase
187 entropy */
188 for(i = 0;i < len;i++) {
189 keybuf[i] = key[i];
190 }
191 s->crypt_method = s->crypt_method_header;
192
193 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
194 return -1;
195 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
196 return -1;
197 #if 0
198 /* test */
199 {
200 uint8_t in[16];
201 uint8_t out[16];
202 uint8_t tmp[16];
203 for(i=0;i<16;i++)
204 in[i] = i;
205 AES_encrypt(in, tmp, &s->aes_encrypt_key);
206 AES_decrypt(tmp, out, &s->aes_decrypt_key);
207 for(i = 0; i < 16; i++)
208 printf(" %02x", tmp[i]);
209 printf("\n");
210 for(i = 0; i < 16; i++)
211 printf(" %02x", out[i]);
212 printf("\n");
213 }
214 #endif
215 return 0;
216 }
217
218 /* The crypt function is compatible with the linux cryptoloop
219 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
220 supported */
221 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
222 uint8_t *out_buf, const uint8_t *in_buf,
223 int nb_sectors, int enc,
224 const AES_KEY *key)
225 {
226 union {
227 uint64_t ll[2];
228 uint8_t b[16];
229 } ivec;
230 int i;
231
232 for(i = 0; i < nb_sectors; i++) {
233 ivec.ll[0] = cpu_to_le64(sector_num);
234 ivec.ll[1] = 0;
235 AES_cbc_encrypt(in_buf, out_buf, 512, key,
236 ivec.b, enc);
237 sector_num++;
238 in_buf += 512;
239 out_buf += 512;
240 }
241 }
242
243 /* 'allocate' is:
244 *
245 * 0 to not allocate.
246 *
247 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
248 * 'n_end')
249 *
250 * 2 to allocate a compressed cluster of size
251 * 'compressed_size'. 'compressed_size' must be > 0 and <
252 * cluster_size
253 *
254 * return 0 if not allocated.
255 */
256 static uint64_t get_cluster_offset(BlockDriverState *bs,
257 uint64_t offset, int allocate,
258 int compressed_size,
259 int n_start, int n_end)
260 {
261 BDRVQcowState *s = bs->opaque;
262 int min_index, i, j, l1_index, l2_index;
263 uint64_t l2_offset, *l2_table, cluster_offset, tmp;
264 uint32_t min_count;
265 int new_l2_table;
266
267 l1_index = offset >> (s->l2_bits + s->cluster_bits);
268 l2_offset = s->l1_table[l1_index];
269 new_l2_table = 0;
270 if (!l2_offset) {
271 if (!allocate)
272 return 0;
273 /* allocate a new l2 entry */
274 l2_offset = bdrv_getlength(s->hd);
275 /* round to cluster size */
276 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
277 /* update the L1 entry */
278 s->l1_table[l1_index] = l2_offset;
279 tmp = cpu_to_be64(l2_offset);
280 if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
281 &tmp, sizeof(tmp)) != sizeof(tmp))
282 return 0;
283 new_l2_table = 1;
284 }
285 for(i = 0; i < L2_CACHE_SIZE; i++) {
286 if (l2_offset == s->l2_cache_offsets[i]) {
287 /* increment the hit count */
288 if (++s->l2_cache_counts[i] == 0xffffffff) {
289 for(j = 0; j < L2_CACHE_SIZE; j++) {
290 s->l2_cache_counts[j] >>= 1;
291 }
292 }
293 l2_table = s->l2_cache + (i << s->l2_bits);
294 goto found;
295 }
296 }
297 /* not found: load a new entry in the least used one */
298 min_index = 0;
299 min_count = 0xffffffff;
300 for(i = 0; i < L2_CACHE_SIZE; i++) {
301 if (s->l2_cache_counts[i] < min_count) {
302 min_count = s->l2_cache_counts[i];
303 min_index = i;
304 }
305 }
306 l2_table = s->l2_cache + (min_index << s->l2_bits);
307 if (new_l2_table) {
308 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
309 if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
310 s->l2_size * sizeof(uint64_t))
311 return 0;
312 } else {
313 if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
314 s->l2_size * sizeof(uint64_t))
315 return 0;
316 }
317 s->l2_cache_offsets[min_index] = l2_offset;
318 s->l2_cache_counts[min_index] = 1;
319 found:
320 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
321 cluster_offset = be64_to_cpu(l2_table[l2_index]);
322 if (!cluster_offset ||
323 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
324 if (!allocate)
325 return 0;
326 /* allocate a new cluster */
327 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
328 (n_end - n_start) < s->cluster_sectors) {
329 /* if the cluster is already compressed, we must
330 decompress it in the case it is not completely
331 overwritten */
332 if (decompress_cluster(s, cluster_offset) < 0)
333 return 0;
334 cluster_offset = bdrv_getlength(s->hd);
335 cluster_offset = (cluster_offset + s->cluster_size - 1) &
336 ~(s->cluster_size - 1);
337 /* write the cluster content */
338 if (bdrv_pwrite(s->hd, cluster_offset, s->cluster_cache, s->cluster_size) !=
339 s->cluster_size)
340 return -1;
341 } else {
342 cluster_offset = bdrv_getlength(s->hd);
343 if (allocate == 1) {
344 /* round to cluster size */
345 cluster_offset = (cluster_offset + s->cluster_size - 1) &
346 ~(s->cluster_size - 1);
347 bdrv_truncate(s->hd, cluster_offset + s->cluster_size);
348 /* if encrypted, we must initialize the cluster
349 content which won't be written */
350 if (s->crypt_method &&
351 (n_end - n_start) < s->cluster_sectors) {
352 uint64_t start_sect;
353 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
354 memset(s->cluster_data + 512, 0x00, 512);
355 for(i = 0; i < s->cluster_sectors; i++) {
356 if (i < n_start || i >= n_end) {
357 encrypt_sectors(s, start_sect + i,
358 s->cluster_data,
359 s->cluster_data + 512, 1, 1,
360 &s->aes_encrypt_key);
361 if (bdrv_pwrite(s->hd, cluster_offset + i * 512,
362 s->cluster_data, 512) != 512)
363 return -1;
364 }
365 }
366 }
367 } else if (allocate == 2) {
368 cluster_offset |= QCOW_OFLAG_COMPRESSED |
369 (uint64_t)compressed_size << (63 - s->cluster_bits);
370 }
371 }
372 /* update L2 table */
373 tmp = cpu_to_be64(cluster_offset);
374 l2_table[l2_index] = tmp;
375 if (bdrv_pwrite(s->hd,
376 l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
377 return 0;
378 }
379 return cluster_offset;
380 }
381
382 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
383 int nb_sectors, int *pnum)
384 {
385 BDRVQcowState *s = bs->opaque;
386 int index_in_cluster, n;
387 uint64_t cluster_offset;
388
389 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
390 index_in_cluster = sector_num & (s->cluster_sectors - 1);
391 n = s->cluster_sectors - index_in_cluster;
392 if (n > nb_sectors)
393 n = nb_sectors;
394 *pnum = n;
395 return (cluster_offset != 0);
396 }
397
398 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
399 const uint8_t *buf, int buf_size)
400 {
401 z_stream strm1, *strm = &strm1;
402 int ret, out_len;
403
404 memset(strm, 0, sizeof(*strm));
405
406 strm->next_in = (uint8_t *)buf;
407 strm->avail_in = buf_size;
408 strm->next_out = out_buf;
409 strm->avail_out = out_buf_size;
410
411 ret = inflateInit2(strm, -12);
412 if (ret != Z_OK)
413 return -1;
414 ret = inflate(strm, Z_FINISH);
415 out_len = strm->next_out - out_buf;
416 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
417 out_len != out_buf_size) {
418 inflateEnd(strm);
419 return -1;
420 }
421 inflateEnd(strm);
422 return 0;
423 }
424
425 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
426 {
427 int ret, csize;
428 uint64_t coffset;
429
430 coffset = cluster_offset & s->cluster_offset_mask;
431 if (s->cluster_cache_offset != coffset) {
432 csize = cluster_offset >> (63 - s->cluster_bits);
433 csize &= (s->cluster_size - 1);
434 ret = bdrv_pread(s->hd, coffset, s->cluster_data, csize);
435 if (ret != csize)
436 return -1;
437 if (decompress_buffer(s->cluster_cache, s->cluster_size,
438 s->cluster_data, csize) < 0) {
439 return -1;
440 }
441 s->cluster_cache_offset = coffset;
442 }
443 return 0;
444 }
445
446 #if 0
447
448 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
449 uint8_t *buf, int nb_sectors)
450 {
451 BDRVQcowState *s = bs->opaque;
452 int ret, index_in_cluster, n;
453 uint64_t cluster_offset;
454
455 while (nb_sectors > 0) {
456 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
457 index_in_cluster = sector_num & (s->cluster_sectors - 1);
458 n = s->cluster_sectors - index_in_cluster;
459 if (n > nb_sectors)
460 n = nb_sectors;
461 if (!cluster_offset) {
462 if (bs->backing_hd) {
463 /* read from the base image */
464 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
465 if (ret < 0)
466 return -1;
467 } else {
468 memset(buf, 0, 512 * n);
469 }
470 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
471 if (decompress_cluster(s, cluster_offset) < 0)
472 return -1;
473 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
474 } else {
475 ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
476 if (ret != n * 512)
477 return -1;
478 if (s->crypt_method) {
479 encrypt_sectors(s, sector_num, buf, buf, n, 0,
480 &s->aes_decrypt_key);
481 }
482 }
483 nb_sectors -= n;
484 sector_num += n;
485 buf += n * 512;
486 }
487 return 0;
488 }
489 #endif
490
491 typedef struct QCowAIOCB {
492 BlockDriverAIOCB common;
493 int64_t sector_num;
494 QEMUIOVector *qiov;
495 uint8_t *buf;
496 void *orig_buf;
497 int nb_sectors;
498 int n;
499 uint64_t cluster_offset;
500 uint8_t *cluster_data;
501 struct iovec hd_iov;
502 QEMUIOVector hd_qiov;
503 BlockDriverAIOCB *hd_aiocb;
504 } QCowAIOCB;
505
506 static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
507 {
508 QCowAIOCB *acb = (QCowAIOCB *)blockacb;
509 if (acb->hd_aiocb)
510 bdrv_aio_cancel(acb->hd_aiocb);
511 qemu_aio_release(acb);
512 }
513
514 static AIOPool qcow_aio_pool = {
515 .aiocb_size = sizeof(QCowAIOCB),
516 .cancel = qcow_aio_cancel,
517 };
518
519 static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
520 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
521 BlockDriverCompletionFunc *cb, void *opaque, int is_write)
522 {
523 QCowAIOCB *acb;
524
525 acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
526 if (!acb)
527 return NULL;
528 acb->hd_aiocb = NULL;
529 acb->sector_num = sector_num;
530 acb->qiov = qiov;
531 if (qiov->niov > 1) {
532 acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
533 if (is_write)
534 qemu_iovec_to_buffer(qiov, acb->buf);
535 } else {
536 acb->buf = (uint8_t *)qiov->iov->iov_base;
537 }
538 acb->nb_sectors = nb_sectors;
539 acb->n = 0;
540 acb->cluster_offset = 0;
541 return acb;
542 }
543
544 static void qcow_aio_read_cb(void *opaque, int ret)
545 {
546 QCowAIOCB *acb = opaque;
547 BlockDriverState *bs = acb->common.bs;
548 BDRVQcowState *s = bs->opaque;
549 int index_in_cluster;
550
551 acb->hd_aiocb = NULL;
552 if (ret < 0)
553 goto done;
554
555 redo:
556 /* post process the read buffer */
557 if (!acb->cluster_offset) {
558 /* nothing to do */
559 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
560 /* nothing to do */
561 } else {
562 if (s->crypt_method) {
563 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
564 acb->n, 0,
565 &s->aes_decrypt_key);
566 }
567 }
568
569 acb->nb_sectors -= acb->n;
570 acb->sector_num += acb->n;
571 acb->buf += acb->n * 512;
572
573 if (acb->nb_sectors == 0) {
574 /* request completed */
575 ret = 0;
576 goto done;
577 }
578
579 /* prepare next AIO request */
580 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
581 0, 0, 0, 0);
582 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
583 acb->n = s->cluster_sectors - index_in_cluster;
584 if (acb->n > acb->nb_sectors)
585 acb->n = acb->nb_sectors;
586
587 if (!acb->cluster_offset) {
588 if (bs->backing_hd) {
589 /* read from the base image */
590 acb->hd_iov.iov_base = (void *)acb->buf;
591 acb->hd_iov.iov_len = acb->n * 512;
592 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
593 acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
594 &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
595 if (acb->hd_aiocb == NULL)
596 goto done;
597 } else {
598 /* Note: in this case, no need to wait */
599 memset(acb->buf, 0, 512 * acb->n);
600 goto redo;
601 }
602 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
603 /* add AIO support for compressed blocks ? */
604 if (decompress_cluster(s, acb->cluster_offset) < 0)
605 goto done;
606 memcpy(acb->buf,
607 s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
608 goto redo;
609 } else {
610 if ((acb->cluster_offset & 511) != 0) {
611 ret = -EIO;
612 goto done;
613 }
614 acb->hd_iov.iov_base = (void *)acb->buf;
615 acb->hd_iov.iov_len = acb->n * 512;
616 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
617 acb->hd_aiocb = bdrv_aio_readv(s->hd,
618 (acb->cluster_offset >> 9) + index_in_cluster,
619 &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
620 if (acb->hd_aiocb == NULL)
621 goto done;
622 }
623
624 return;
625
626 done:
627 if (acb->qiov->niov > 1) {
628 qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
629 qemu_vfree(acb->orig_buf);
630 }
631 acb->common.cb(acb->common.opaque, ret);
632 qemu_aio_release(acb);
633 }
634
635 static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
636 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
637 BlockDriverCompletionFunc *cb, void *opaque)
638 {
639 QCowAIOCB *acb;
640
641 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
642 if (!acb)
643 return NULL;
644
645 qcow_aio_read_cb(acb, 0);
646 return &acb->common;
647 }
648
649 static void qcow_aio_write_cb(void *opaque, int ret)
650 {
651 QCowAIOCB *acb = opaque;
652 BlockDriverState *bs = acb->common.bs;
653 BDRVQcowState *s = bs->opaque;
654 int index_in_cluster;
655 uint64_t cluster_offset;
656 const uint8_t *src_buf;
657
658 acb->hd_aiocb = NULL;
659
660 if (ret < 0)
661 goto done;
662
663 acb->nb_sectors -= acb->n;
664 acb->sector_num += acb->n;
665 acb->buf += acb->n * 512;
666
667 if (acb->nb_sectors == 0) {
668 /* request completed */
669 ret = 0;
670 goto done;
671 }
672
673 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
674 acb->n = s->cluster_sectors - index_in_cluster;
675 if (acb->n > acb->nb_sectors)
676 acb->n = acb->nb_sectors;
677 cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
678 index_in_cluster,
679 index_in_cluster + acb->n);
680 if (!cluster_offset || (cluster_offset & 511) != 0) {
681 ret = -EIO;
682 goto done;
683 }
684 if (s->crypt_method) {
685 if (!acb->cluster_data) {
686 acb->cluster_data = qemu_mallocz(s->cluster_size);
687 if (!acb->cluster_data) {
688 ret = -ENOMEM;
689 goto done;
690 }
691 }
692 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
693 acb->n, 1, &s->aes_encrypt_key);
694 src_buf = acb->cluster_data;
695 } else {
696 src_buf = acb->buf;
697 }
698
699 acb->hd_iov.iov_base = (void *)src_buf;
700 acb->hd_iov.iov_len = acb->n * 512;
701 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
702 acb->hd_aiocb = bdrv_aio_writev(s->hd,
703 (cluster_offset >> 9) + index_in_cluster,
704 &acb->hd_qiov, acb->n,
705 qcow_aio_write_cb, acb);
706 if (acb->hd_aiocb == NULL)
707 goto done;
708 return;
709
710 done:
711 if (acb->qiov->niov > 1)
712 qemu_vfree(acb->orig_buf);
713 acb->common.cb(acb->common.opaque, ret);
714 qemu_aio_release(acb);
715 }
716
717 static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
718 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
719 BlockDriverCompletionFunc *cb, void *opaque)
720 {
721 BDRVQcowState *s = bs->opaque;
722 QCowAIOCB *acb;
723
724 s->cluster_cache_offset = -1; /* disable compressed cache */
725
726 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
727 if (!acb)
728 return NULL;
729
730
731 qcow_aio_write_cb(acb, 0);
732 return &acb->common;
733 }
734
735 static void qcow_close(BlockDriverState *bs)
736 {
737 BDRVQcowState *s = bs->opaque;
738 qemu_free(s->l1_table);
739 qemu_free(s->l2_cache);
740 qemu_free(s->cluster_cache);
741 qemu_free(s->cluster_data);
742 bdrv_delete(s->hd);
743 }
744
745 static int qcow_create(const char *filename, QEMUOptionParameter *options)
746 {
747 int fd, header_size, backing_filename_len, l1_size, i, shift;
748 QCowHeader header;
749 uint64_t tmp;
750 int64_t total_size = 0;
751 const char *backing_file = NULL;
752 int flags = 0;
753
754 /* Read out options */
755 while (options && options->name) {
756 if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
757 total_size = options->value.n / 512;
758 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
759 backing_file = options->value.s;
760 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
761 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
762 }
763 options++;
764 }
765
766 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
767 if (fd < 0)
768 return -1;
769 memset(&header, 0, sizeof(header));
770 header.magic = cpu_to_be32(QCOW_MAGIC);
771 header.version = cpu_to_be32(QCOW_VERSION);
772 header.size = cpu_to_be64(total_size * 512);
773 header_size = sizeof(header);
774 backing_filename_len = 0;
775 if (backing_file) {
776 if (strcmp(backing_file, "fat:")) {
777 header.backing_file_offset = cpu_to_be64(header_size);
778 backing_filename_len = strlen(backing_file);
779 header.backing_file_size = cpu_to_be32(backing_filename_len);
780 header_size += backing_filename_len;
781 } else {
782 /* special backing file for vvfat */
783 backing_file = NULL;
784 }
785 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
786 unmodifyed sectors */
787 header.l2_bits = 12; /* 32 KB L2 tables */
788 } else {
789 header.cluster_bits = 12; /* 4 KB clusters */
790 header.l2_bits = 9; /* 4 KB L2 tables */
791 }
792 header_size = (header_size + 7) & ~7;
793 shift = header.cluster_bits + header.l2_bits;
794 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
795
796 header.l1_table_offset = cpu_to_be64(header_size);
797 if (flags & BLOCK_FLAG_ENCRYPT) {
798 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
799 } else {
800 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
801 }
802
803 /* write all the data */
804 write(fd, &header, sizeof(header));
805 if (backing_file) {
806 write(fd, backing_file, backing_filename_len);
807 }
808 lseek(fd, header_size, SEEK_SET);
809 tmp = 0;
810 for(i = 0;i < l1_size; i++) {
811 write(fd, &tmp, sizeof(tmp));
812 }
813 close(fd);
814 return 0;
815 }
816
817 static int qcow_make_empty(BlockDriverState *bs)
818 {
819 BDRVQcowState *s = bs->opaque;
820 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
821 int ret;
822
823 memset(s->l1_table, 0, l1_length);
824 if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
825 return -1;
826 ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
827 if (ret < 0)
828 return ret;
829
830 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
831 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
832 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
833
834 return 0;
835 }
836
837 /* XXX: put compressed sectors first, then all the cluster aligned
838 tables to avoid losing bytes in alignment */
839 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
840 const uint8_t *buf, int nb_sectors)
841 {
842 BDRVQcowState *s = bs->opaque;
843 z_stream strm;
844 int ret, out_len;
845 uint8_t *out_buf;
846 uint64_t cluster_offset;
847
848 if (nb_sectors != s->cluster_sectors)
849 return -EINVAL;
850
851 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
852 if (!out_buf)
853 return -1;
854
855 /* best compression, small window, no zlib header */
856 memset(&strm, 0, sizeof(strm));
857 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
858 Z_DEFLATED, -12,
859 9, Z_DEFAULT_STRATEGY);
860 if (ret != 0) {
861 qemu_free(out_buf);
862 return -1;
863 }
864
865 strm.avail_in = s->cluster_size;
866 strm.next_in = (uint8_t *)buf;
867 strm.avail_out = s->cluster_size;
868 strm.next_out = out_buf;
869
870 ret = deflate(&strm, Z_FINISH);
871 if (ret != Z_STREAM_END && ret != Z_OK) {
872 qemu_free(out_buf);
873 deflateEnd(&strm);
874 return -1;
875 }
876 out_len = strm.next_out - out_buf;
877
878 deflateEnd(&strm);
879
880 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
881 /* could not compress: write normal cluster */
882 bdrv_write(bs, sector_num, buf, s->cluster_sectors);
883 } else {
884 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
885 out_len, 0, 0);
886 cluster_offset &= s->cluster_offset_mask;
887 if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
888 qemu_free(out_buf);
889 return -1;
890 }
891 }
892
893 qemu_free(out_buf);
894 return 0;
895 }
896
897 static void qcow_flush(BlockDriverState *bs)
898 {
899 BDRVQcowState *s = bs->opaque;
900 bdrv_flush(s->hd);
901 }
902
903 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
904 {
905 BDRVQcowState *s = bs->opaque;
906 bdi->cluster_size = s->cluster_size;
907 return 0;
908 }
909
910
911 static QEMUOptionParameter qcow_create_options[] = {
912 {
913 .name = BLOCK_OPT_SIZE,
914 .type = OPT_SIZE,
915 .help = "Virtual disk size"
916 },
917 {
918 .name = BLOCK_OPT_BACKING_FILE,
919 .type = OPT_STRING,
920 .help = "File name of a base image"
921 },
922 {
923 .name = BLOCK_OPT_ENCRYPT,
924 .type = OPT_FLAG,
925 .help = "Encrypt the image"
926 },
927 { NULL }
928 };
929
930 static BlockDriver bdrv_qcow = {
931 .format_name = "qcow",
932 .instance_size = sizeof(BDRVQcowState),
933 .bdrv_probe = qcow_probe,
934 .bdrv_open = qcow_open,
935 .bdrv_close = qcow_close,
936 .bdrv_create = qcow_create,
937 .bdrv_flush = qcow_flush,
938 .bdrv_is_allocated = qcow_is_allocated,
939 .bdrv_set_key = qcow_set_key,
940 .bdrv_make_empty = qcow_make_empty,
941 .bdrv_aio_readv = qcow_aio_readv,
942 .bdrv_aio_writev = qcow_aio_writev,
943 .bdrv_write_compressed = qcow_write_compressed,
944 .bdrv_get_info = qcow_get_info,
945
946 .create_options = qcow_create_options,
947 };
948
949 static void bdrv_qcow_init(void)
950 {
951 bdrv_register(&bdrv_qcow);
952 }
953
954 block_init(bdrv_qcow_init);
AR7 emulation for QEMU