?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
qemu:virtio-net: Check return size on the correct sg list (Alex Williamson)
[qemu.git] / block-qcow.c
blob91c53b1b8eb17d344961d97424d85c7a97b45ee7
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 <zlib.h>
27 #include "aes.h"
28
29 /**************************************************************/
30 /* QEMU COW block driver with compression and encryption support */
31
32 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
33 #define QCOW_VERSION 1
34
35 #define QCOW_CRYPT_NONE 0
36 #define QCOW_CRYPT_AES 1
37
38 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
39
40 typedef struct QCowHeader {
41 uint32_t magic;
42 uint32_t version;
43 uint64_t backing_file_offset;
44 uint32_t backing_file_size;
45 uint32_t mtime;
46 uint64_t size; /* in bytes */
47 uint8_t cluster_bits;
48 uint8_t l2_bits;
49 uint32_t crypt_method;
50 uint64_t l1_table_offset;
51 } QCowHeader;
52
53 #define L2_CACHE_SIZE 16
54
55 typedef struct BDRVQcowState {
56 BlockDriverState *hd;
57 int cluster_bits;
58 int cluster_size;
59 int cluster_sectors;
60 int l2_bits;
61 int l2_size;
62 int l1_size;
63 uint64_t cluster_offset_mask;
64 uint64_t l1_table_offset;
65 uint64_t *l1_table;
66 uint64_t *l2_cache;
67 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
68 uint32_t l2_cache_counts[L2_CACHE_SIZE];
69 uint8_t *cluster_cache;
70 uint8_t *cluster_data;
71 uint64_t cluster_cache_offset;
72 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
73 uint32_t crypt_method_header;
74 AES_KEY aes_encrypt_key;
75 AES_KEY aes_decrypt_key;
76 } BDRVQcowState;
77
78 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
79
80 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
81 {
82 const QCowHeader *cow_header = (const void *)buf;
83
84 if (buf_size >= sizeof(QCowHeader) &&
85 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
86 be32_to_cpu(cow_header->version) == QCOW_VERSION)
87 return 100;
88 else
89 return 0;
90 }
91
92 static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
93 {
94 BDRVQcowState *s = bs->opaque;
95 int len, i, shift, ret;
96 QCowHeader header;
97
98 ret = bdrv_file_open(&s->hd, filename, flags);
99 if (ret < 0)
100 return ret;
101 if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
102 goto fail;
103 be32_to_cpus(&header.magic);
104 be32_to_cpus(&header.version);
105 be64_to_cpus(&header.backing_file_offset);
106 be32_to_cpus(&header.backing_file_size);
107 be32_to_cpus(&header.mtime);
108 be64_to_cpus(&header.size);
109 be32_to_cpus(&header.crypt_method);
110 be64_to_cpus(&header.l1_table_offset);
111
112 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
113 goto fail;
114 if (header.size <= 1 || header.cluster_bits < 9)
115 goto fail;
116 if (header.crypt_method > QCOW_CRYPT_AES)
117 goto fail;
118 s->crypt_method_header = header.crypt_method;
119 if (s->crypt_method_header)
120 bs->encrypted = 1;
121 s->cluster_bits = header.cluster_bits;
122 s->cluster_size = 1 << s->cluster_bits;
123 s->cluster_sectors = 1 << (s->cluster_bits - 9);
124 s->l2_bits = header.l2_bits;
125 s->l2_size = 1 << s->l2_bits;
126 bs->total_sectors = header.size / 512;
127 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
128
129 /* read the level 1 table */
130 shift = s->cluster_bits + s->l2_bits;
131 s->l1_size = (header.size + (1LL << shift) - 1) >> shift;
132
133 s->l1_table_offset = header.l1_table_offset;
134 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
135 if (!s->l1_table)
136 goto fail;
137 if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
138 s->l1_size * sizeof(uint64_t))
139 goto fail;
140 for(i = 0;i < s->l1_size; i++) {
141 be64_to_cpus(&s->l1_table[i]);
142 }
143 /* alloc L2 cache */
144 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
145 if (!s->l2_cache)
146 goto fail;
147 s->cluster_cache = qemu_malloc(s->cluster_size);
148 if (!s->cluster_cache)
149 goto fail;
150 s->cluster_data = qemu_malloc(s->cluster_size);
151 if (!s->cluster_data)
152 goto fail;
153 s->cluster_cache_offset = -1;
154
155 /* read the backing file name */
156 if (header.backing_file_offset != 0) {
157 len = header.backing_file_size;
158 if (len > 1023)
159 len = 1023;
160 if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
161 goto fail;
162 bs->backing_file[len] = '\0';
163 }
164 return 0;
165
166 fail:
167 qemu_free(s->l1_table);
168 qemu_free(s->l2_cache);
169 qemu_free(s->cluster_cache);
170 qemu_free(s->cluster_data);
171 bdrv_delete(s->hd);
172 return -1;
173 }
174
175 static int qcow_set_key(BlockDriverState *bs, const char *key)
176 {
177 BDRVQcowState *s = bs->opaque;
178 uint8_t keybuf[16];
179 int len, i;
180
181 memset(keybuf, 0, 16);
182 len = strlen(key);
183 if (len > 16)
184 len = 16;
185 /* XXX: we could compress the chars to 7 bits to increase
186 entropy */
187 for(i = 0;i < len;i++) {
188 keybuf[i] = key[i];
189 }
190 s->crypt_method = s->crypt_method_header;
191
192 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
193 return -1;
194 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
195 return -1;
196 #if 0
197 /* test */
198 {
199 uint8_t in[16];
200 uint8_t out[16];
201 uint8_t tmp[16];
202 for(i=0;i<16;i++)
203 in[i] = i;
204 AES_encrypt(in, tmp, &s->aes_encrypt_key);
205 AES_decrypt(tmp, out, &s->aes_decrypt_key);
206 for(i = 0; i < 16; i++)
207 printf(" %02x", tmp[i]);
208 printf("\n");
209 for(i = 0; i < 16; i++)
210 printf(" %02x", out[i]);
211 printf("\n");
212 }
213 #endif
214 return 0;
215 }
216
217 /* The crypt function is compatible with the linux cryptoloop
218 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
219 supported */
220 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
221 uint8_t *out_buf, const uint8_t *in_buf,
222 int nb_sectors, int enc,
223 const AES_KEY *key)
224 {
225 union {
226 uint64_t ll[2];
227 uint8_t b[16];
228 } ivec;
229 int i;
230
231 for(i = 0; i < nb_sectors; i++) {
232 ivec.ll[0] = cpu_to_le64(sector_num);
233 ivec.ll[1] = 0;
234 AES_cbc_encrypt(in_buf, out_buf, 512, key,
235 ivec.b, enc);
236 sector_num++;
237 in_buf += 512;
238 out_buf += 512;
239 }
240 }
241
242 /* 'allocate' is:
243 *
244 * 0 to not allocate.
245 *
246 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
247 * 'n_end')
248 *
249 * 2 to allocate a compressed cluster of size
250 * 'compressed_size'. 'compressed_size' must be > 0 and <
251 * cluster_size
252 *
253 * return 0 if not allocated.
254 */
255 static uint64_t get_cluster_offset(BlockDriverState *bs,
256 uint64_t offset, int allocate,
257 int compressed_size,
258 int n_start, int n_end)
259 {
260 BDRVQcowState *s = bs->opaque;
261 int min_index, i, j, l1_index, l2_index;
262 uint64_t l2_offset, *l2_table, cluster_offset, tmp;
263 uint32_t min_count;
264 int new_l2_table;
265
266 l1_index = offset >> (s->l2_bits + s->cluster_bits);
267 l2_offset = s->l1_table[l1_index];
268 new_l2_table = 0;
269 if (!l2_offset) {
270 if (!allocate)
271 return 0;
272 /* allocate a new l2 entry */
273 l2_offset = bdrv_getlength(s->hd);
274 /* round to cluster size */
275 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
276 /* update the L1 entry */
277 s->l1_table[l1_index] = l2_offset;
278 tmp = cpu_to_be64(l2_offset);
279 if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
280 &tmp, sizeof(tmp)) != sizeof(tmp))
281 return 0;
282 new_l2_table = 1;
283 }
284 for(i = 0; i < L2_CACHE_SIZE; i++) {
285 if (l2_offset == s->l2_cache_offsets[i]) {
286 /* increment the hit count */
287 if (++s->l2_cache_counts[i] == 0xffffffff) {
288 for(j = 0; j < L2_CACHE_SIZE; j++) {
289 s->l2_cache_counts[j] >>= 1;
290 }
291 }
292 l2_table = s->l2_cache + (i << s->l2_bits);
293 goto found;
294 }
295 }
296 /* not found: load a new entry in the least used one */
297 min_index = 0;
298 min_count = 0xffffffff;
299 for(i = 0; i < L2_CACHE_SIZE; i++) {
300 if (s->l2_cache_counts[i] < min_count) {
301 min_count = s->l2_cache_counts[i];
302 min_index = i;
303 }
304 }
305 l2_table = s->l2_cache + (min_index << s->l2_bits);
306 if (new_l2_table) {
307 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
308 if (bdrv_pwrite(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
309 s->l2_size * sizeof(uint64_t))
310 return 0;
311 } else {
312 if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
313 s->l2_size * sizeof(uint64_t))
314 return 0;
315 }
316 s->l2_cache_offsets[min_index] = l2_offset;
317 s->l2_cache_counts[min_index] = 1;
318 found:
319 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
320 cluster_offset = be64_to_cpu(l2_table[l2_index]);
321 if (!cluster_offset ||
322 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
323 if (!allocate)
324 return 0;
325 /* allocate a new cluster */
326 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
327 (n_end - n_start) < s->cluster_sectors) {
328 /* if the cluster is already compressed, we must
329 decompress it in the case it is not completely
330 overwritten */
331 if (decompress_cluster(s, cluster_offset) < 0)
332 return 0;
333 cluster_offset = bdrv_getlength(s->hd);
334 cluster_offset = (cluster_offset + s->cluster_size - 1) &
335 ~(s->cluster_size - 1);
336 /* write the cluster content */
337 if (bdrv_pwrite(s->hd, cluster_offset, s->cluster_cache, s->cluster_size) !=
338 s->cluster_size)
339 return -1;
340 } else {
341 cluster_offset = bdrv_getlength(s->hd);
342 if (allocate == 1) {
343 /* round to cluster size */
344 cluster_offset = (cluster_offset + s->cluster_size - 1) &
345 ~(s->cluster_size - 1);
346 bdrv_truncate(s->hd, cluster_offset + s->cluster_size);
347 /* if encrypted, we must initialize the cluster
348 content which won't be written */
349 if (s->crypt_method &&
350 (n_end - n_start) < s->cluster_sectors) {
351 uint64_t start_sect;
352 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
353 memset(s->cluster_data + 512, 0x00, 512);
354 for(i = 0; i < s->cluster_sectors; i++) {
355 if (i < n_start || i >= n_end) {
356 encrypt_sectors(s, start_sect + i,
357 s->cluster_data,
358 s->cluster_data + 512, 1, 1,
359 &s->aes_encrypt_key);
360 if (bdrv_pwrite(s->hd, cluster_offset + i * 512,
361 s->cluster_data, 512) != 512)
362 return -1;
363 }
364 }
365 }
366 } else if (allocate == 2) {
367 cluster_offset |= QCOW_OFLAG_COMPRESSED |
368 (uint64_t)compressed_size << (63 - s->cluster_bits);
369 }
370 }
371 /* update L2 table */
372 tmp = cpu_to_be64(cluster_offset);
373 l2_table[l2_index] = tmp;
374 if (bdrv_pwrite(s->hd,
375 l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
376 return 0;
377 }
378 return cluster_offset;
379 }
380
381 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
382 int nb_sectors, int *pnum)
383 {
384 BDRVQcowState *s = bs->opaque;
385 int index_in_cluster, n;
386 uint64_t cluster_offset;
387
388 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
389 index_in_cluster = sector_num & (s->cluster_sectors - 1);
390 n = s->cluster_sectors - index_in_cluster;
391 if (n > nb_sectors)
392 n = nb_sectors;
393 *pnum = n;
394 return (cluster_offset != 0);
395 }
396
397 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
398 const uint8_t *buf, int buf_size)
399 {
400 z_stream strm1, *strm = &strm1;
401 int ret, out_len;
402
403 memset(strm, 0, sizeof(*strm));
404
405 strm->next_in = (uint8_t *)buf;
406 strm->avail_in = buf_size;
407 strm->next_out = out_buf;
408 strm->avail_out = out_buf_size;
409
410 ret = inflateInit2(strm, -12);
411 if (ret != Z_OK)
412 return -1;
413 ret = inflate(strm, Z_FINISH);
414 out_len = strm->next_out - out_buf;
415 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
416 out_len != out_buf_size) {
417 inflateEnd(strm);
418 return -1;
419 }
420 inflateEnd(strm);
421 return 0;
422 }
423
424 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
425 {
426 int ret, csize;
427 uint64_t coffset;
428
429 coffset = cluster_offset & s->cluster_offset_mask;
430 if (s->cluster_cache_offset != coffset) {
431 csize = cluster_offset >> (63 - s->cluster_bits);
432 csize &= (s->cluster_size - 1);
433 ret = bdrv_pread(s->hd, coffset, s->cluster_data, csize);
434 if (ret != csize)
435 return -1;
436 if (decompress_buffer(s->cluster_cache, s->cluster_size,
437 s->cluster_data, csize) < 0) {
438 return -1;
439 }
440 s->cluster_cache_offset = coffset;
441 }
442 return 0;
443 }
444
445 #if 0
446
447 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
448 uint8_t *buf, int nb_sectors)
449 {
450 BDRVQcowState *s = bs->opaque;
451 int ret, index_in_cluster, n;
452 uint64_t cluster_offset;
453
454 while (nb_sectors > 0) {
455 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
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 if (!cluster_offset) {
461 if (bs->backing_hd) {
462 /* read from the base image */
463 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
464 if (ret < 0)
465 return -1;
466 } else {
467 memset(buf, 0, 512 * n);
468 }
469 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
470 if (decompress_cluster(s, cluster_offset) < 0)
471 return -1;
472 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
473 } else {
474 ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
475 if (ret != n * 512)
476 return -1;
477 if (s->crypt_method) {
478 encrypt_sectors(s, sector_num, buf, buf, n, 0,
479 &s->aes_decrypt_key);
480 }
481 }
482 nb_sectors -= n;
483 sector_num += n;
484 buf += n * 512;
485 }
486 return 0;
487 }
488 #endif
489
490 static int qcow_write(BlockDriverState *bs, int64_t sector_num,
491 const uint8_t *buf, int nb_sectors)
492 {
493 BDRVQcowState *s = bs->opaque;
494 int ret, index_in_cluster, n;
495 uint64_t cluster_offset;
496
497 while (nb_sectors > 0) {
498 index_in_cluster = sector_num & (s->cluster_sectors - 1);
499 n = s->cluster_sectors - index_in_cluster;
500 if (n > nb_sectors)
501 n = nb_sectors;
502 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
503 index_in_cluster,
504 index_in_cluster + n);
505 if (!cluster_offset)
506 return -1;
507 if (s->crypt_method) {
508 encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
509 &s->aes_encrypt_key);
510 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
511 s->cluster_data, n * 512);
512 } else {
513 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
514 }
515 if (ret != n * 512)
516 return -1;
517 nb_sectors -= n;
518 sector_num += n;
519 buf += n * 512;
520 }
521 s->cluster_cache_offset = -1; /* disable compressed cache */
522 return 0;
523 }
524
525 typedef struct QCowAIOCB {
526 BlockDriverAIOCB common;
527 int64_t sector_num;
528 uint8_t *buf;
529 int nb_sectors;
530 int n;
531 uint64_t cluster_offset;
532 uint8_t *cluster_data;
533 BlockDriverAIOCB *hd_aiocb;
534 } QCowAIOCB;
535
536 static void qcow_aio_read_cb(void *opaque, int ret)
537 {
538 QCowAIOCB *acb = opaque;
539 BlockDriverState *bs = acb->common.bs;
540 BDRVQcowState *s = bs->opaque;
541 int index_in_cluster;
542
543 acb->hd_aiocb = NULL;
544 if (ret < 0) {
545 fail:
546 acb->common.cb(acb->common.opaque, ret);
547 qemu_aio_release(acb);
548 return;
549 }
550
551 redo:
552 /* post process the read buffer */
553 if (!acb->cluster_offset) {
554 /* nothing to do */
555 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
556 /* nothing to do */
557 } else {
558 if (s->crypt_method) {
559 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
560 acb->n, 0,
561 &s->aes_decrypt_key);
562 }
563 }
564
565 acb->nb_sectors -= acb->n;
566 acb->sector_num += acb->n;
567 acb->buf += acb->n * 512;
568
569 if (acb->nb_sectors == 0) {
570 /* request completed */
571 acb->common.cb(acb->common.opaque, 0);
572 qemu_aio_release(acb);
573 return;
574 }
575
576 /* prepare next AIO request */
577 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
578 0, 0, 0, 0);
579 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
580 acb->n = s->cluster_sectors - index_in_cluster;
581 if (acb->n > acb->nb_sectors)
582 acb->n = acb->nb_sectors;
583
584 if (!acb->cluster_offset) {
585 if (bs->backing_hd) {
586 /* read from the base image */
587 acb->hd_aiocb = bdrv_aio_read(bs->backing_hd,
588 acb->sector_num, acb->buf, acb->n, qcow_aio_read_cb, acb);
589 if (acb->hd_aiocb == NULL)
590 goto fail;
591 } else {
592 /* Note: in this case, no need to wait */
593 memset(acb->buf, 0, 512 * acb->n);
594 goto redo;
595 }
596 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
597 /* add AIO support for compressed blocks ? */
598 if (decompress_cluster(s, acb->cluster_offset) < 0)
599 goto fail;
600 memcpy(acb->buf,
601 s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
602 goto redo;
603 } else {
604 if ((acb->cluster_offset & 511) != 0) {
605 ret = -EIO;
606 goto fail;
607 }
608 acb->hd_aiocb = bdrv_aio_read(s->hd,
609 (acb->cluster_offset >> 9) + index_in_cluster,
610 acb->buf, acb->n, qcow_aio_read_cb, acb);
611 if (acb->hd_aiocb == NULL)
612 goto fail;
613 }
614 }
615
616 static BlockDriverAIOCB *qcow_aio_read(BlockDriverState *bs,
617 int64_t sector_num, uint8_t *buf, int nb_sectors,
618 BlockDriverCompletionFunc *cb, void *opaque)
619 {
620 QCowAIOCB *acb;
621
622 acb = qemu_aio_get(bs, cb, opaque);
623 if (!acb)
624 return NULL;
625 acb->hd_aiocb = NULL;
626 acb->sector_num = sector_num;
627 acb->buf = buf;
628 acb->nb_sectors = nb_sectors;
629 acb->n = 0;
630 acb->cluster_offset = 0;
631
632 qcow_aio_read_cb(acb, 0);
633 return &acb->common;
634 }
635
636 static void qcow_aio_write_cb(void *opaque, int ret)
637 {
638 QCowAIOCB *acb = opaque;
639 BlockDriverState *bs = acb->common.bs;
640 BDRVQcowState *s = bs->opaque;
641 int index_in_cluster;
642 uint64_t cluster_offset;
643 const uint8_t *src_buf;
644
645 acb->hd_aiocb = NULL;
646
647 if (ret < 0) {
648 fail:
649 acb->common.cb(acb->common.opaque, ret);
650 qemu_aio_release(acb);
651 return;
652 }
653
654 acb->nb_sectors -= acb->n;
655 acb->sector_num += acb->n;
656 acb->buf += acb->n * 512;
657
658 if (acb->nb_sectors == 0) {
659 /* request completed */
660 acb->common.cb(acb->common.opaque, 0);
661 qemu_aio_release(acb);
662 return;
663 }
664
665 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
666 acb->n = s->cluster_sectors - index_in_cluster;
667 if (acb->n > acb->nb_sectors)
668 acb->n = acb->nb_sectors;
669 cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
670 index_in_cluster,
671 index_in_cluster + acb->n);
672 if (!cluster_offset || (cluster_offset & 511) != 0) {
673 ret = -EIO;
674 goto fail;
675 }
676 if (s->crypt_method) {
677 if (!acb->cluster_data) {
678 acb->cluster_data = qemu_mallocz(s->cluster_size);
679 if (!acb->cluster_data) {
680 ret = -ENOMEM;
681 goto fail;
682 }
683 }
684 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
685 acb->n, 1, &s->aes_encrypt_key);
686 src_buf = acb->cluster_data;
687 } else {
688 src_buf = acb->buf;
689 }
690 acb->hd_aiocb = bdrv_aio_write(s->hd,
691 (cluster_offset >> 9) + index_in_cluster,
692 src_buf, acb->n,
693 qcow_aio_write_cb, acb);
694 if (acb->hd_aiocb == NULL)
695 goto fail;
696 }
697
698 static BlockDriverAIOCB *qcow_aio_write(BlockDriverState *bs,
699 int64_t sector_num, const uint8_t *buf, int nb_sectors,
700 BlockDriverCompletionFunc *cb, void *opaque)
701 {
702 BDRVQcowState *s = bs->opaque;
703 QCowAIOCB *acb;
704
705 s->cluster_cache_offset = -1; /* disable compressed cache */
706
707 acb = qemu_aio_get(bs, cb, opaque);
708 if (!acb)
709 return NULL;
710 acb->hd_aiocb = NULL;
711 acb->sector_num = sector_num;
712 acb->buf = (uint8_t *)buf;
713 acb->nb_sectors = nb_sectors;
714 acb->n = 0;
715
716 qcow_aio_write_cb(acb, 0);
717 return &acb->common;
718 }
719
720 static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
721 {
722 QCowAIOCB *acb = (QCowAIOCB *)blockacb;
723 if (acb->hd_aiocb)
724 bdrv_aio_cancel(acb->hd_aiocb);
725 qemu_aio_release(acb);
726 }
727
728 static void qcow_close(BlockDriverState *bs)
729 {
730 BDRVQcowState *s = bs->opaque;
731 qemu_free(s->l1_table);
732 qemu_free(s->l2_cache);
733 qemu_free(s->cluster_cache);
734 qemu_free(s->cluster_data);
735 bdrv_delete(s->hd);
736 }
737
738 static int qcow_create(const char *filename, int64_t total_size,
739 const char *backing_file, int flags)
740 {
741 int fd, header_size, backing_filename_len, l1_size, i, shift;
742 QCowHeader header;
743 uint64_t tmp;
744
745 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
746 if (fd < 0)
747 return -1;
748 memset(&header, 0, sizeof(header));
749 header.magic = cpu_to_be32(QCOW_MAGIC);
750 header.version = cpu_to_be32(QCOW_VERSION);
751 header.size = cpu_to_be64(total_size * 512);
752 header_size = sizeof(header);
753 backing_filename_len = 0;
754 if (backing_file) {
755 if (strcmp(backing_file, "fat:")) {
756 header.backing_file_offset = cpu_to_be64(header_size);
757 backing_filename_len = strlen(backing_file);
758 header.backing_file_size = cpu_to_be32(backing_filename_len);
759 header_size += backing_filename_len;
760 } else {
761 /* special backing file for vvfat */
762 backing_file = NULL;
763 }
764 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
765 unmodifyed sectors */
766 header.l2_bits = 12; /* 32 KB L2 tables */
767 } else {
768 header.cluster_bits = 12; /* 4 KB clusters */
769 header.l2_bits = 9; /* 4 KB L2 tables */
770 }
771 header_size = (header_size + 7) & ~7;
772 shift = header.cluster_bits + header.l2_bits;
773 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
774
775 header.l1_table_offset = cpu_to_be64(header_size);
776 if (flags & BLOCK_FLAG_ENCRYPT) {
777 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
778 } else {
779 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
780 }
781
782 /* write all the data */
783 write(fd, &header, sizeof(header));
784 if (backing_file) {
785 write(fd, backing_file, backing_filename_len);
786 }
787 lseek(fd, header_size, SEEK_SET);
788 tmp = 0;
789 for(i = 0;i < l1_size; i++) {
790 write(fd, &tmp, sizeof(tmp));
791 }
792 close(fd);
793 return 0;
794 }
795
796 static int qcow_make_empty(BlockDriverState *bs)
797 {
798 BDRVQcowState *s = bs->opaque;
799 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
800 int ret;
801
802 memset(s->l1_table, 0, l1_length);
803 if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
804 return -1;
805 ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
806 if (ret < 0)
807 return ret;
808
809 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
810 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
811 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
812
813 return 0;
814 }
815
816 /* XXX: put compressed sectors first, then all the cluster aligned
817 tables to avoid losing bytes in alignment */
818 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
819 const uint8_t *buf, int nb_sectors)
820 {
821 BDRVQcowState *s = bs->opaque;
822 z_stream strm;
823 int ret, out_len;
824 uint8_t *out_buf;
825 uint64_t cluster_offset;
826
827 if (nb_sectors != s->cluster_sectors)
828 return -EINVAL;
829
830 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
831 if (!out_buf)
832 return -1;
833
834 /* best compression, small window, no zlib header */
835 memset(&strm, 0, sizeof(strm));
836 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
837 Z_DEFLATED, -12,
838 9, Z_DEFAULT_STRATEGY);
839 if (ret != 0) {
840 qemu_free(out_buf);
841 return -1;
842 }
843
844 strm.avail_in = s->cluster_size;
845 strm.next_in = (uint8_t *)buf;
846 strm.avail_out = s->cluster_size;
847 strm.next_out = out_buf;
848
849 ret = deflate(&strm, Z_FINISH);
850 if (ret != Z_STREAM_END && ret != Z_OK) {
851 qemu_free(out_buf);
852 deflateEnd(&strm);
853 return -1;
854 }
855 out_len = strm.next_out - out_buf;
856
857 deflateEnd(&strm);
858
859 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
860 /* could not compress: write normal cluster */
861 qcow_write(bs, sector_num, buf, s->cluster_sectors);
862 } else {
863 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
864 out_len, 0, 0);
865 cluster_offset &= s->cluster_offset_mask;
866 if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
867 qemu_free(out_buf);
868 return -1;
869 }
870 }
871
872 qemu_free(out_buf);
873 return 0;
874 }
875
876 static void qcow_flush(BlockDriverState *bs)
877 {
878 BDRVQcowState *s = bs->opaque;
879 bdrv_flush(s->hd);
880 }
881
882 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
883 {
884 BDRVQcowState *s = bs->opaque;
885 bdi->cluster_size = s->cluster_size;
886 return 0;
887 }
888
889 BlockDriver bdrv_qcow = {
890 "qcow",
891 sizeof(BDRVQcowState),
892 qcow_probe,
893 qcow_open,
894 NULL,
895 NULL,
896 qcow_close,
897 qcow_create,
898 qcow_flush,
899 qcow_is_allocated,
900 qcow_set_key,
901 qcow_make_empty,
902
903 .bdrv_aio_read = qcow_aio_read,
904 .bdrv_aio_write = qcow_aio_write,
905 .bdrv_aio_cancel = qcow_aio_cancel,
906 .aiocb_size = sizeof(QCowAIOCB),
907 .bdrv_write_compressed = qcow_write_compressed,
908 .bdrv_get_info = qcow_get_info,
909 };
QEmu