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virtio-blk: Create exit function to unregister savevm
[qemu/kevin.git] / block / qcow.c
blob816103d395aecd68d6ace43df8477f79f1ce0624
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(BlockDriverState *bs, 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, int flags)
94 {
95 BDRVQcowState *s = bs->opaque;
96 int len, i, shift;
97 QCowHeader header;
98
99 if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header))
100 goto fail;
101 be32_to_cpus(&header.magic);
102 be32_to_cpus(&header.version);
103 be64_to_cpus(&header.backing_file_offset);
104 be32_to_cpus(&header.backing_file_size);
105 be32_to_cpus(&header.mtime);
106 be64_to_cpus(&header.size);
107 be32_to_cpus(&header.crypt_method);
108 be64_to_cpus(&header.l1_table_offset);
109
110 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
111 goto fail;
112 if (header.size <= 1 || header.cluster_bits < 9)
113 goto fail;
114 if (header.crypt_method > QCOW_CRYPT_AES)
115 goto fail;
116 s->crypt_method_header = header.crypt_method;
117 if (s->crypt_method_header)
118 bs->encrypted = 1;
119 s->cluster_bits = header.cluster_bits;
120 s->cluster_size = 1 << s->cluster_bits;
121 s->cluster_sectors = 1 << (s->cluster_bits - 9);
122 s->l2_bits = header.l2_bits;
123 s->l2_size = 1 << s->l2_bits;
124 bs->total_sectors = header.size / 512;
125 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
126
127 /* read the level 1 table */
128 shift = s->cluster_bits + s->l2_bits;
129 s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
130
131 s->l1_table_offset = header.l1_table_offset;
132 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
133 if (!s->l1_table)
134 goto fail;
135 if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
136 s->l1_size * sizeof(uint64_t))
137 goto fail;
138 for(i = 0;i < s->l1_size; i++) {
139 be64_to_cpus(&s->l1_table[i]);
140 }
141 /* alloc L2 cache */
142 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
143 if (!s->l2_cache)
144 goto fail;
145 s->cluster_cache = qemu_malloc(s->cluster_size);
146 if (!s->cluster_cache)
147 goto fail;
148 s->cluster_data = qemu_malloc(s->cluster_size);
149 if (!s->cluster_data)
150 goto fail;
151 s->cluster_cache_offset = -1;
152
153 /* read the backing file name */
154 if (header.backing_file_offset != 0) {
155 len = header.backing_file_size;
156 if (len > 1023)
157 len = 1023;
158 if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len)
159 goto fail;
160 bs->backing_file[len] = '\0';
161 }
162 return 0;
163
164 fail:
165 qemu_free(s->l1_table);
166 qemu_free(s->l2_cache);
167 qemu_free(s->cluster_cache);
168 qemu_free(s->cluster_data);
169 return -1;
170 }
171
172 static int qcow_set_key(BlockDriverState *bs, const char *key)
173 {
174 BDRVQcowState *s = bs->opaque;
175 uint8_t keybuf[16];
176 int len, i;
177
178 memset(keybuf, 0, 16);
179 len = strlen(key);
180 if (len > 16)
181 len = 16;
182 /* XXX: we could compress the chars to 7 bits to increase
183 entropy */
184 for(i = 0;i < len;i++) {
185 keybuf[i] = key[i];
186 }
187 s->crypt_method = s->crypt_method_header;
188
189 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
190 return -1;
191 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
192 return -1;
193 #if 0
194 /* test */
195 {
196 uint8_t in[16];
197 uint8_t out[16];
198 uint8_t tmp[16];
199 for(i=0;i<16;i++)
200 in[i] = i;
201 AES_encrypt(in, tmp, &s->aes_encrypt_key);
202 AES_decrypt(tmp, out, &s->aes_decrypt_key);
203 for(i = 0; i < 16; i++)
204 printf(" %02x", tmp[i]);
205 printf("\n");
206 for(i = 0; i < 16; i++)
207 printf(" %02x", out[i]);
208 printf("\n");
209 }
210 #endif
211 return 0;
212 }
213
214 /* The crypt function is compatible with the linux cryptoloop
215 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
216 supported */
217 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
218 uint8_t *out_buf, const uint8_t *in_buf,
219 int nb_sectors, int enc,
220 const AES_KEY *key)
221 {
222 union {
223 uint64_t ll[2];
224 uint8_t b[16];
225 } ivec;
226 int i;
227
228 for(i = 0; i < nb_sectors; i++) {
229 ivec.ll[0] = cpu_to_le64(sector_num);
230 ivec.ll[1] = 0;
231 AES_cbc_encrypt(in_buf, out_buf, 512, key,
232 ivec.b, enc);
233 sector_num++;
234 in_buf += 512;
235 out_buf += 512;
236 }
237 }
238
239 /* 'allocate' is:
240 *
241 * 0 to not allocate.
242 *
243 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
244 * 'n_end')
245 *
246 * 2 to allocate a compressed cluster of size
247 * 'compressed_size'. 'compressed_size' must be > 0 and <
248 * cluster_size
249 *
250 * return 0 if not allocated.
251 */
252 static uint64_t get_cluster_offset(BlockDriverState *bs,
253 uint64_t offset, int allocate,
254 int compressed_size,
255 int n_start, int n_end)
256 {
257 BDRVQcowState *s = bs->opaque;
258 int min_index, i, j, l1_index, l2_index;
259 uint64_t l2_offset, *l2_table, cluster_offset, tmp;
260 uint32_t min_count;
261 int new_l2_table;
262
263 l1_index = offset >> (s->l2_bits + s->cluster_bits);
264 l2_offset = s->l1_table[l1_index];
265 new_l2_table = 0;
266 if (!l2_offset) {
267 if (!allocate)
268 return 0;
269 /* allocate a new l2 entry */
270 l2_offset = bdrv_getlength(bs->file);
271 /* round to cluster size */
272 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
273 /* update the L1 entry */
274 s->l1_table[l1_index] = l2_offset;
275 tmp = cpu_to_be64(l2_offset);
276 if (bdrv_pwrite_sync(bs->file,
277 s->l1_table_offset + l1_index * sizeof(tmp),
278 &tmp, sizeof(tmp)) < 0)
279 return 0;
280 new_l2_table = 1;
281 }
282 for(i = 0; i < L2_CACHE_SIZE; i++) {
283 if (l2_offset == s->l2_cache_offsets[i]) {
284 /* increment the hit count */
285 if (++s->l2_cache_counts[i] == 0xffffffff) {
286 for(j = 0; j < L2_CACHE_SIZE; j++) {
287 s->l2_cache_counts[j] >>= 1;
288 }
289 }
290 l2_table = s->l2_cache + (i << s->l2_bits);
291 goto found;
292 }
293 }
294 /* not found: load a new entry in the least used one */
295 min_index = 0;
296 min_count = 0xffffffff;
297 for(i = 0; i < L2_CACHE_SIZE; i++) {
298 if (s->l2_cache_counts[i] < min_count) {
299 min_count = s->l2_cache_counts[i];
300 min_index = i;
301 }
302 }
303 l2_table = s->l2_cache + (min_index << s->l2_bits);
304 if (new_l2_table) {
305 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
306 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
307 s->l2_size * sizeof(uint64_t)) < 0)
308 return 0;
309 } else {
310 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
311 s->l2_size * sizeof(uint64_t))
312 return 0;
313 }
314 s->l2_cache_offsets[min_index] = l2_offset;
315 s->l2_cache_counts[min_index] = 1;
316 found:
317 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
318 cluster_offset = be64_to_cpu(l2_table[l2_index]);
319 if (!cluster_offset ||
320 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
321 if (!allocate)
322 return 0;
323 /* allocate a new cluster */
324 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
325 (n_end - n_start) < s->cluster_sectors) {
326 /* if the cluster is already compressed, we must
327 decompress it in the case it is not completely
328 overwritten */
329 if (decompress_cluster(bs, cluster_offset) < 0)
330 return 0;
331 cluster_offset = bdrv_getlength(bs->file);
332 cluster_offset = (cluster_offset + s->cluster_size - 1) &
333 ~(s->cluster_size - 1);
334 /* write the cluster content */
335 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
336 s->cluster_size)
337 return -1;
338 } else {
339 cluster_offset = bdrv_getlength(bs->file);
340 if (allocate == 1) {
341 /* round to cluster size */
342 cluster_offset = (cluster_offset + s->cluster_size - 1) &
343 ~(s->cluster_size - 1);
344 bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
345 /* if encrypted, we must initialize the cluster
346 content which won't be written */
347 if (s->crypt_method &&
348 (n_end - n_start) < s->cluster_sectors) {
349 uint64_t start_sect;
350 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
351 memset(s->cluster_data + 512, 0x00, 512);
352 for(i = 0; i < s->cluster_sectors; i++) {
353 if (i < n_start || i >= n_end) {
354 encrypt_sectors(s, start_sect + i,
355 s->cluster_data,
356 s->cluster_data + 512, 1, 1,
357 &s->aes_encrypt_key);
358 if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
359 s->cluster_data, 512) != 512)
360 return -1;
361 }
362 }
363 }
364 } else if (allocate == 2) {
365 cluster_offset |= QCOW_OFLAG_COMPRESSED |
366 (uint64_t)compressed_size << (63 - s->cluster_bits);
367 }
368 }
369 /* update L2 table */
370 tmp = cpu_to_be64(cluster_offset);
371 l2_table[l2_index] = tmp;
372 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
373 &tmp, sizeof(tmp)) < 0)
374 return 0;
375 }
376 return cluster_offset;
377 }
378
379 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
380 int nb_sectors, int *pnum)
381 {
382 BDRVQcowState *s = bs->opaque;
383 int index_in_cluster, n;
384 uint64_t cluster_offset;
385
386 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
387 index_in_cluster = sector_num & (s->cluster_sectors - 1);
388 n = s->cluster_sectors - index_in_cluster;
389 if (n > nb_sectors)
390 n = nb_sectors;
391 *pnum = n;
392 return (cluster_offset != 0);
393 }
394
395 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
396 const uint8_t *buf, int buf_size)
397 {
398 z_stream strm1, *strm = &strm1;
399 int ret, out_len;
400
401 memset(strm, 0, sizeof(*strm));
402
403 strm->next_in = (uint8_t *)buf;
404 strm->avail_in = buf_size;
405 strm->next_out = out_buf;
406 strm->avail_out = out_buf_size;
407
408 ret = inflateInit2(strm, -12);
409 if (ret != Z_OK)
410 return -1;
411 ret = inflate(strm, Z_FINISH);
412 out_len = strm->next_out - out_buf;
413 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
414 out_len != out_buf_size) {
415 inflateEnd(strm);
416 return -1;
417 }
418 inflateEnd(strm);
419 return 0;
420 }
421
422 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
423 {
424 BDRVQcowState *s = bs->opaque;
425 int ret, csize;
426 uint64_t coffset;
427
428 coffset = cluster_offset & s->cluster_offset_mask;
429 if (s->cluster_cache_offset != coffset) {
430 csize = cluster_offset >> (63 - s->cluster_bits);
431 csize &= (s->cluster_size - 1);
432 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
433 if (ret != csize)
434 return -1;
435 if (decompress_buffer(s->cluster_cache, s->cluster_size,
436 s->cluster_data, csize) < 0) {
437 return -1;
438 }
439 s->cluster_cache_offset = coffset;
440 }
441 return 0;
442 }
443
444 #if 0
445
446 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
447 uint8_t *buf, int nb_sectors)
448 {
449 BDRVQcowState *s = bs->opaque;
450 int ret, index_in_cluster, n;
451 uint64_t cluster_offset;
452
453 while (nb_sectors > 0) {
454 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
455 index_in_cluster = sector_num & (s->cluster_sectors - 1);
456 n = s->cluster_sectors - index_in_cluster;
457 if (n > nb_sectors)
458 n = nb_sectors;
459 if (!cluster_offset) {
460 if (bs->backing_hd) {
461 /* read from the base image */
462 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
463 if (ret < 0)
464 return -1;
465 } else {
466 memset(buf, 0, 512 * n);
467 }
468 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
469 if (decompress_cluster(bs, cluster_offset) < 0)
470 return -1;
471 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
472 } else {
473 ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
474 if (ret != n * 512)
475 return -1;
476 if (s->crypt_method) {
477 encrypt_sectors(s, sector_num, buf, buf, n, 0,
478 &s->aes_decrypt_key);
479 }
480 }
481 nb_sectors -= n;
482 sector_num += n;
483 buf += n * 512;
484 }
485 return 0;
486 }
487 #endif
488
489 typedef struct QCowAIOCB {
490 BlockDriverAIOCB common;
491 int64_t sector_num;
492 QEMUIOVector *qiov;
493 uint8_t *buf;
494 void *orig_buf;
495 int nb_sectors;
496 int n;
497 uint64_t cluster_offset;
498 uint8_t *cluster_data;
499 struct iovec hd_iov;
500 QEMUIOVector hd_qiov;
501 BlockDriverAIOCB *hd_aiocb;
502 } QCowAIOCB;
503
504 static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
505 {
506 QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common);
507 if (acb->hd_aiocb)
508 bdrv_aio_cancel(acb->hd_aiocb);
509 qemu_aio_release(acb);
510 }
511
512 static AIOPool qcow_aio_pool = {
513 .aiocb_size = sizeof(QCowAIOCB),
514 .cancel = qcow_aio_cancel,
515 };
516
517 static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
518 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
519 BlockDriverCompletionFunc *cb, void *opaque, int is_write)
520 {
521 QCowAIOCB *acb;
522
523 acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
524 if (!acb)
525 return NULL;
526 acb->hd_aiocb = NULL;
527 acb->sector_num = sector_num;
528 acb->qiov = qiov;
529 if (qiov->niov > 1) {
530 acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
531 if (is_write)
532 qemu_iovec_to_buffer(qiov, acb->buf);
533 } else {
534 acb->buf = (uint8_t *)qiov->iov->iov_base;
535 }
536 acb->nb_sectors = nb_sectors;
537 acb->n = 0;
538 acb->cluster_offset = 0;
539 return acb;
540 }
541
542 static void qcow_aio_read_cb(void *opaque, int ret)
543 {
544 QCowAIOCB *acb = opaque;
545 BlockDriverState *bs = acb->common.bs;
546 BDRVQcowState *s = bs->opaque;
547 int index_in_cluster;
548
549 acb->hd_aiocb = NULL;
550 if (ret < 0)
551 goto done;
552
553 redo:
554 /* post process the read buffer */
555 if (!acb->cluster_offset) {
556 /* nothing to do */
557 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
558 /* nothing to do */
559 } else {
560 if (s->crypt_method) {
561 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
562 acb->n, 0,
563 &s->aes_decrypt_key);
564 }
565 }
566
567 acb->nb_sectors -= acb->n;
568 acb->sector_num += acb->n;
569 acb->buf += acb->n * 512;
570
571 if (acb->nb_sectors == 0) {
572 /* request completed */
573 ret = 0;
574 goto done;
575 }
576
577 /* prepare next AIO request */
578 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
579 0, 0, 0, 0);
580 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
581 acb->n = s->cluster_sectors - index_in_cluster;
582 if (acb->n > acb->nb_sectors)
583 acb->n = acb->nb_sectors;
584
585 if (!acb->cluster_offset) {
586 if (bs->backing_hd) {
587 /* read from the base image */
588 acb->hd_iov.iov_base = (void *)acb->buf;
589 acb->hd_iov.iov_len = acb->n * 512;
590 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
591 acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
592 &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
593 if (acb->hd_aiocb == NULL)
594 goto done;
595 } else {
596 /* Note: in this case, no need to wait */
597 memset(acb->buf, 0, 512 * acb->n);
598 goto redo;
599 }
600 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
601 /* add AIO support for compressed blocks ? */
602 if (decompress_cluster(bs, acb->cluster_offset) < 0)
603 goto done;
604 memcpy(acb->buf,
605 s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
606 goto redo;
607 } else {
608 if ((acb->cluster_offset & 511) != 0) {
609 ret = -EIO;
610 goto done;
611 }
612 acb->hd_iov.iov_base = (void *)acb->buf;
613 acb->hd_iov.iov_len = acb->n * 512;
614 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
615 acb->hd_aiocb = bdrv_aio_readv(bs->file,
616 (acb->cluster_offset >> 9) + index_in_cluster,
617 &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
618 if (acb->hd_aiocb == NULL)
619 goto done;
620 }
621
622 return;
623
624 done:
625 if (acb->qiov->niov > 1) {
626 qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
627 qemu_vfree(acb->orig_buf);
628 }
629 acb->common.cb(acb->common.opaque, ret);
630 qemu_aio_release(acb);
631 }
632
633 static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
634 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
635 BlockDriverCompletionFunc *cb, void *opaque)
636 {
637 QCowAIOCB *acb;
638
639 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
640 if (!acb)
641 return NULL;
642
643 qcow_aio_read_cb(acb, 0);
644 return &acb->common;
645 }
646
647 static void qcow_aio_write_cb(void *opaque, int ret)
648 {
649 QCowAIOCB *acb = opaque;
650 BlockDriverState *bs = acb->common.bs;
651 BDRVQcowState *s = bs->opaque;
652 int index_in_cluster;
653 uint64_t cluster_offset;
654 const uint8_t *src_buf;
655
656 acb->hd_aiocb = NULL;
657
658 if (ret < 0)
659 goto done;
660
661 acb->nb_sectors -= acb->n;
662 acb->sector_num += acb->n;
663 acb->buf += acb->n * 512;
664
665 if (acb->nb_sectors == 0) {
666 /* request completed */
667 ret = 0;
668 goto done;
669 }
670
671 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
672 acb->n = s->cluster_sectors - index_in_cluster;
673 if (acb->n > acb->nb_sectors)
674 acb->n = acb->nb_sectors;
675 cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
676 index_in_cluster,
677 index_in_cluster + acb->n);
678 if (!cluster_offset || (cluster_offset & 511) != 0) {
679 ret = -EIO;
680 goto done;
681 }
682 if (s->crypt_method) {
683 if (!acb->cluster_data) {
684 acb->cluster_data = qemu_mallocz(s->cluster_size);
685 if (!acb->cluster_data) {
686 ret = -ENOMEM;
687 goto done;
688 }
689 }
690 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
691 acb->n, 1, &s->aes_encrypt_key);
692 src_buf = acb->cluster_data;
693 } else {
694 src_buf = acb->buf;
695 }
696
697 acb->hd_iov.iov_base = (void *)src_buf;
698 acb->hd_iov.iov_len = acb->n * 512;
699 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
700 acb->hd_aiocb = bdrv_aio_writev(bs->file,
701 (cluster_offset >> 9) + index_in_cluster,
702 &acb->hd_qiov, acb->n,
703 qcow_aio_write_cb, acb);
704 if (acb->hd_aiocb == NULL)
705 goto done;
706 return;
707
708 done:
709 if (acb->qiov->niov > 1)
710 qemu_vfree(acb->orig_buf);
711 acb->common.cb(acb->common.opaque, ret);
712 qemu_aio_release(acb);
713 }
714
715 static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
716 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
717 BlockDriverCompletionFunc *cb, void *opaque)
718 {
719 BDRVQcowState *s = bs->opaque;
720 QCowAIOCB *acb;
721
722 s->cluster_cache_offset = -1; /* disable compressed cache */
723
724 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
725 if (!acb)
726 return NULL;
727
728
729 qcow_aio_write_cb(acb, 0);
730 return &acb->common;
731 }
732
733 static void qcow_close(BlockDriverState *bs)
734 {
735 BDRVQcowState *s = bs->opaque;
736 qemu_free(s->l1_table);
737 qemu_free(s->l2_cache);
738 qemu_free(s->cluster_cache);
739 qemu_free(s->cluster_data);
740 }
741
742 static int qcow_create(const char *filename, QEMUOptionParameter *options)
743 {
744 int fd, header_size, backing_filename_len, l1_size, i, shift;
745 QCowHeader header;
746 uint64_t tmp;
747 int64_t total_size = 0;
748 const char *backing_file = NULL;
749 int flags = 0;
750 int ret;
751
752 /* Read out options */
753 while (options && options->name) {
754 if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
755 total_size = options->value.n / 512;
756 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
757 backing_file = options->value.s;
758 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
759 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
760 }
761 options++;
762 }
763
764 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
765 if (fd < 0)
766 return -errno;
767 memset(&header, 0, sizeof(header));
768 header.magic = cpu_to_be32(QCOW_MAGIC);
769 header.version = cpu_to_be32(QCOW_VERSION);
770 header.size = cpu_to_be64(total_size * 512);
771 header_size = sizeof(header);
772 backing_filename_len = 0;
773 if (backing_file) {
774 if (strcmp(backing_file, "fat:")) {
775 header.backing_file_offset = cpu_to_be64(header_size);
776 backing_filename_len = strlen(backing_file);
777 header.backing_file_size = cpu_to_be32(backing_filename_len);
778 header_size += backing_filename_len;
779 } else {
780 /* special backing file for vvfat */
781 backing_file = NULL;
782 }
783 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
784 unmodifyed sectors */
785 header.l2_bits = 12; /* 32 KB L2 tables */
786 } else {
787 header.cluster_bits = 12; /* 4 KB clusters */
788 header.l2_bits = 9; /* 4 KB L2 tables */
789 }
790 header_size = (header_size + 7) & ~7;
791 shift = header.cluster_bits + header.l2_bits;
792 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
793
794 header.l1_table_offset = cpu_to_be64(header_size);
795 if (flags & BLOCK_FLAG_ENCRYPT) {
796 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
797 } else {
798 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
799 }
800
801 /* write all the data */
802 ret = qemu_write_full(fd, &header, sizeof(header));
803 if (ret != sizeof(header)) {
804 ret = -errno;
805 goto exit;
806 }
807
808 if (backing_file) {
809 ret = qemu_write_full(fd, backing_file, backing_filename_len);
810 if (ret != backing_filename_len) {
811 ret = -errno;
812 goto exit;
813 }
814
815 }
816 lseek(fd, header_size, SEEK_SET);
817 tmp = 0;
818 for(i = 0;i < l1_size; i++) {
819 ret = qemu_write_full(fd, &tmp, sizeof(tmp));
820 if (ret != sizeof(tmp)) {
821 ret = -errno;
822 goto exit;
823 }
824 }
825
826 ret = 0;
827 exit:
828 close(fd);
829 return ret;
830 }
831
832 static int qcow_make_empty(BlockDriverState *bs)
833 {
834 BDRVQcowState *s = bs->opaque;
835 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
836 int ret;
837
838 memset(s->l1_table, 0, l1_length);
839 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
840 l1_length) < 0)
841 return -1;
842 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
843 if (ret < 0)
844 return ret;
845
846 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
847 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
848 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
849
850 return 0;
851 }
852
853 /* XXX: put compressed sectors first, then all the cluster aligned
854 tables to avoid losing bytes in alignment */
855 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
856 const uint8_t *buf, int nb_sectors)
857 {
858 BDRVQcowState *s = bs->opaque;
859 z_stream strm;
860 int ret, out_len;
861 uint8_t *out_buf;
862 uint64_t cluster_offset;
863
864 if (nb_sectors != s->cluster_sectors)
865 return -EINVAL;
866
867 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
868 if (!out_buf)
869 return -1;
870
871 /* best compression, small window, no zlib header */
872 memset(&strm, 0, sizeof(strm));
873 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
874 Z_DEFLATED, -12,
875 9, Z_DEFAULT_STRATEGY);
876 if (ret != 0) {
877 qemu_free(out_buf);
878 return -1;
879 }
880
881 strm.avail_in = s->cluster_size;
882 strm.next_in = (uint8_t *)buf;
883 strm.avail_out = s->cluster_size;
884 strm.next_out = out_buf;
885
886 ret = deflate(&strm, Z_FINISH);
887 if (ret != Z_STREAM_END && ret != Z_OK) {
888 qemu_free(out_buf);
889 deflateEnd(&strm);
890 return -1;
891 }
892 out_len = strm.next_out - out_buf;
893
894 deflateEnd(&strm);
895
896 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
897 /* could not compress: write normal cluster */
898 bdrv_write(bs, sector_num, buf, s->cluster_sectors);
899 } else {
900 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
901 out_len, 0, 0);
902 cluster_offset &= s->cluster_offset_mask;
903 if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
904 qemu_free(out_buf);
905 return -1;
906 }
907 }
908
909 qemu_free(out_buf);
910 return 0;
911 }
912
913 static void qcow_flush(BlockDriverState *bs)
914 {
915 bdrv_flush(bs->file);
916 }
917
918 static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs,
919 BlockDriverCompletionFunc *cb, void *opaque)
920 {
921 return bdrv_aio_flush(bs->file, cb, opaque);
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
932 static QEMUOptionParameter qcow_create_options[] = {
933 {
934 .name = BLOCK_OPT_SIZE,
935 .type = OPT_SIZE,
936 .help = "Virtual disk size"
937 },
938 {
939 .name = BLOCK_OPT_BACKING_FILE,
940 .type = OPT_STRING,
941 .help = "File name of a base image"
942 },
943 {
944 .name = BLOCK_OPT_ENCRYPT,
945 .type = OPT_FLAG,
946 .help = "Encrypt the image"
947 },
948 { NULL }
949 };
950
951 static BlockDriver bdrv_qcow = {
952 .format_name = "qcow",
953 .instance_size = sizeof(BDRVQcowState),
954 .bdrv_probe = qcow_probe,
955 .bdrv_open = qcow_open,
956 .bdrv_close = qcow_close,
957 .bdrv_create = qcow_create,
958 .bdrv_flush = qcow_flush,
959 .bdrv_is_allocated = qcow_is_allocated,
960 .bdrv_set_key = qcow_set_key,
961 .bdrv_make_empty = qcow_make_empty,
962 .bdrv_aio_readv = qcow_aio_readv,
963 .bdrv_aio_writev = qcow_aio_writev,
964 .bdrv_aio_flush = qcow_aio_flush,
965 .bdrv_write_compressed = qcow_write_compressed,
966 .bdrv_get_info = qcow_get_info,
967
968 .create_options = qcow_create_options,
969 };
970
971 static void bdrv_qcow_init(void)
972 {
973 bdrv_register(&bdrv_qcow);
974 }
975
976 block_init(bdrv_qcow_init);
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