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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 "vl.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, 0xaa, 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 {
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 {
526
    int64_t sector_num;
527
    uint8_t *buf;
528
    int nb_sectors;
529
    int n;
530
    uint64_t cluster_offset;
531
    uint8_t *cluster_data; 
532
    BlockDriverAIOCB *hd_aiocb;
533
    BlockDriverAIOCB *backing_hd_aiocb;
534
} QCowAIOCB;
535

    
536
static void qcow_aio_delete(BlockDriverAIOCB *acb);
537

    
538
static int qcow_aio_new(BlockDriverAIOCB *acb)
539
{
540
    BlockDriverState *bs = acb->bs;
541
    BDRVQcowState *s = bs->opaque;
542
    QCowAIOCB *acb1;
543
    acb1 = qemu_mallocz(sizeof(QCowAIOCB));
544
    if (!acb1)
545
        return -1;
546
    acb->opaque = acb1;
547
    acb1->hd_aiocb = bdrv_aio_new(s->hd);
548
    if (!acb1->hd_aiocb)
549
        goto fail;
550
    if (bs->backing_hd) {
551
        acb1->backing_hd_aiocb = bdrv_aio_new(bs->backing_hd);
552
        if (!acb1->backing_hd_aiocb)
553
            goto fail;
554
    }
555
    return 0;
556
 fail:
557
    qcow_aio_delete(acb);
558
    return -1;
559
}
560

    
561
static void qcow_aio_read_cb(void *opaque, int ret)
562
{
563
    BlockDriverAIOCB *acb = opaque;
564
    BlockDriverState *bs = acb->bs;
565
    BDRVQcowState *s = bs->opaque;
566
    QCowAIOCB *acb1 = acb->opaque;
567
    int index_in_cluster;
568

    
569
    if (ret < 0) {
570
    fail:
571
        acb->cb(acb->cb_opaque, ret);
572
        return;
573
    }
574

    
575
 redo:
576
    /* post process the read buffer */
577
    if (!acb1->cluster_offset) {
578
        /* nothing to do */
579
    } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) {
580
        /* nothing to do */
581
    } else {
582
        if (s->crypt_method) {
583
            encrypt_sectors(s, acb1->sector_num, acb1->buf, acb1->buf, 
584
                            acb1->n, 0, 
585
                            &s->aes_decrypt_key);
586
        }
587
    }
588

    
589
    acb1->nb_sectors -= acb1->n;
590
    acb1->sector_num += acb1->n;
591
    acb1->buf += acb1->n * 512;
592

    
593
    if (acb1->nb_sectors == 0) {
594
        /* request completed */
595
        acb->cb(acb->cb_opaque, 0);
596
        return;
597
    }
598
    
599
    /* prepare next AIO request */
600
    acb1->cluster_offset = get_cluster_offset(bs, 
601
                                              acb1->sector_num << 9, 
602
                                              0, 0, 0, 0);
603
    index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1);
604
    acb1->n = s->cluster_sectors - index_in_cluster;
605
    if (acb1->n > acb1->nb_sectors)
606
        acb1->n = acb1->nb_sectors;
607

    
608
    if (!acb1->cluster_offset) {
609
        if (bs->backing_hd) {
610
            /* read from the base image */
611
            ret = bdrv_aio_read(acb1->backing_hd_aiocb, acb1->sector_num, 
612
                                acb1->buf, acb1->n, qcow_aio_read_cb, acb);
613
            if (ret < 0)
614
                goto fail;
615
        } else {
616
            /* Note: in this case, no need to wait */
617
            memset(acb1->buf, 0, 512 * acb1->n);
618
            goto redo;
619
        }
620
    } else if (acb1->cluster_offset & QCOW_OFLAG_COMPRESSED) {
621
        /* add AIO support for compressed blocks ? */
622
        if (decompress_cluster(s, acb1->cluster_offset) < 0)
623
            goto fail;
624
        memcpy(acb1->buf, 
625
               s->cluster_cache + index_in_cluster * 512, 512 * acb1->n);
626
        goto redo;
627
    } else {
628
        if ((acb1->cluster_offset & 511) != 0) {
629
            ret = -EIO;
630
            goto fail;
631
        }
632
        ret = bdrv_aio_read(acb1->hd_aiocb, 
633
                            (acb1->cluster_offset >> 9) + index_in_cluster, 
634
                            acb1->buf, acb1->n, qcow_aio_read_cb, acb);
635
        if (ret < 0)
636
            goto fail;
637
    }
638
}
639

    
640
static int qcow_aio_read(BlockDriverAIOCB *acb, int64_t sector_num, 
641
                         uint8_t *buf, int nb_sectors)
642
{
643
    QCowAIOCB *acb1 = acb->opaque;
644
    
645
    acb1->sector_num = sector_num;
646
    acb1->buf = buf;
647
    acb1->nb_sectors = nb_sectors;
648
    acb1->n = 0;
649
    acb1->cluster_offset = 0;    
650

    
651
    qcow_aio_read_cb(acb, 0);
652
}
653

    
654
static void qcow_aio_write_cb(void *opaque, int ret)
655
{
656
    BlockDriverAIOCB *acb = opaque;
657
    BlockDriverState *bs = acb->bs;
658
    BDRVQcowState *s = bs->opaque;
659
    QCowAIOCB *acb1 = acb->opaque;
660
    int index_in_cluster;
661
    uint64_t cluster_offset;
662
    const uint8_t *src_buf;
663
    
664
    if (ret < 0) {
665
    fail:
666
        acb->cb(acb->cb_opaque, ret);
667
        return;
668
    }
669

    
670
    acb1->nb_sectors -= acb1->n;
671
    acb1->sector_num += acb1->n;
672
    acb1->buf += acb1->n * 512;
673

    
674
    if (acb1->nb_sectors == 0) {
675
        /* request completed */
676
        acb->cb(acb->cb_opaque, 0);
677
        return;
678
    }
679
    
680
    index_in_cluster = acb1->sector_num & (s->cluster_sectors - 1);
681
    acb1->n = s->cluster_sectors - index_in_cluster;
682
    if (acb1->n > acb1->nb_sectors)
683
        acb1->n = acb1->nb_sectors;
684
    cluster_offset = get_cluster_offset(bs, acb1->sector_num << 9, 1, 0, 
685
                                        index_in_cluster, 
686
                                        index_in_cluster + acb1->n);
687
    if (!cluster_offset || (cluster_offset & 511) != 0) {
688
        ret = -EIO;
689
        goto fail;
690
    }
691
    if (s->crypt_method) {
692
        if (!acb1->cluster_data) {
693
            acb1->cluster_data = qemu_mallocz(s->cluster_size);
694
            if (!acb1->cluster_data) {
695
                ret = -ENOMEM;
696
                goto fail;
697
            }
698
        }
699
        encrypt_sectors(s, acb1->sector_num, acb1->cluster_data, acb1->buf, 
700
                        acb1->n, 1, &s->aes_encrypt_key);
701
        src_buf = acb1->cluster_data;
702
    } else {
703
        src_buf = acb1->buf;
704
    }
705
    ret = bdrv_aio_write(acb1->hd_aiocb, 
706
                         (cluster_offset >> 9) + index_in_cluster, 
707
                         src_buf, acb1->n, 
708
                         qcow_aio_write_cb, acb);
709
    if (ret < 0)
710
        goto fail;
711
}
712

    
713
static int qcow_aio_write(BlockDriverAIOCB *acb, int64_t sector_num, 
714
                          const uint8_t *buf, int nb_sectors)
715
{
716
    QCowAIOCB *acb1 = acb->opaque;
717
    BlockDriverState *bs = acb->bs;
718
    BDRVQcowState *s = bs->opaque;
719
    
720
    s->cluster_cache_offset = -1; /* disable compressed cache */
721

    
722
    acb1->sector_num = sector_num;
723
    acb1->buf = (uint8_t *)buf;
724
    acb1->nb_sectors = nb_sectors;
725
    acb1->n = 0;
726
    
727
    qcow_aio_write_cb(acb, 0);
728
}
729

    
730
static void qcow_aio_cancel(BlockDriverAIOCB *acb)
731
{
732
    QCowAIOCB *acb1 = acb->opaque;
733
    if (acb1->hd_aiocb)
734
        bdrv_aio_cancel(acb1->hd_aiocb);
735
    if (acb1->backing_hd_aiocb)
736
        bdrv_aio_cancel(acb1->backing_hd_aiocb);
737
}
738

    
739
static void qcow_aio_delete(BlockDriverAIOCB *acb)
740
{
741
    QCowAIOCB *acb1 = acb->opaque;
742
    if (acb1->hd_aiocb)
743
        bdrv_aio_delete(acb1->hd_aiocb);
744
    if (acb1->backing_hd_aiocb)
745
        bdrv_aio_delete(acb1->backing_hd_aiocb);
746
    qemu_free(acb1->cluster_data);
747
    qemu_free(acb1);
748
}
749

    
750
static void qcow_close(BlockDriverState *bs)
751
{
752
    BDRVQcowState *s = bs->opaque;
753
    qemu_free(s->l1_table);
754
    qemu_free(s->l2_cache);
755
    qemu_free(s->cluster_cache);
756
    qemu_free(s->cluster_data);
757
    bdrv_delete(s->hd);
758
}
759

    
760
static int qcow_create(const char *filename, int64_t total_size,
761
                      const char *backing_file, int flags)
762
{
763
    int fd, header_size, backing_filename_len, l1_size, i, shift;
764
    QCowHeader header;
765
    uint64_t tmp;
766

    
767
    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
768
    if (fd < 0)
769
        return -1;
770
    memset(&header, 0, sizeof(header));
771
    header.magic = cpu_to_be32(QCOW_MAGIC);
772
    header.version = cpu_to_be32(QCOW_VERSION);
773
    header.size = cpu_to_be64(total_size * 512);
774
    header_size = sizeof(header);
775
    backing_filename_len = 0;
776
    if (backing_file) {
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
        header.mtime = cpu_to_be32(0);
782
        header.cluster_bits = 9; /* 512 byte cluster to avoid copying
783
                                    unmodifyed sectors */
784
        header.l2_bits = 12; /* 32 KB L2 tables */
785
    } else {
786
        header.cluster_bits = 12; /* 4 KB clusters */
787
        header.l2_bits = 9; /* 4 KB L2 tables */
788
    }
789
    header_size = (header_size + 7) & ~7;
790
    shift = header.cluster_bits + header.l2_bits;
791
    l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
792

    
793
    header.l1_table_offset = cpu_to_be64(header_size);
794
    if (flags) {
795
        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
796
    } else {
797
        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
798
    }
799
    
800
    /* write all the data */
801
    write(fd, &header, sizeof(header));
802
    if (backing_file) {
803
        write(fd, backing_file, backing_filename_len);
804
    }
805
    lseek(fd, header_size, SEEK_SET);
806
    tmp = 0;
807
    for(i = 0;i < l1_size; i++) {
808
        write(fd, &tmp, sizeof(tmp));
809
    }
810
    close(fd);
811
    return 0;
812
}
813

    
814
int qcow_make_empty(BlockDriverState *bs)
815
{
816
    BDRVQcowState *s = bs->opaque;
817
    uint32_t l1_length = s->l1_size * sizeof(uint64_t);
818
    int ret;
819

    
820
    memset(s->l1_table, 0, l1_length);
821
    if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
822
        return -1;
823
    ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
824
    if (ret < 0)
825
        return ret;
826

    
827
    memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
828
    memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
829
    memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
830

    
831
    return 0;
832
}
833

    
834
int qcow_get_cluster_size(BlockDriverState *bs)
835
{
836
    BDRVQcowState *s = bs->opaque;
837
    if (bs->drv != &bdrv_qcow)
838
        return -1;
839
    return s->cluster_size;
840
}
841

    
842
/* XXX: put compressed sectors first, then all the cluster aligned
843
   tables to avoid losing bytes in alignment */
844
int qcow_compress_cluster(BlockDriverState *bs, int64_t sector_num, 
845
                          const uint8_t *buf)
846
{
847
    BDRVQcowState *s = bs->opaque;
848
    z_stream strm;
849
    int ret, out_len;
850
    uint8_t *out_buf;
851
    uint64_t cluster_offset;
852

    
853
    if (bs->drv != &bdrv_qcow)
854
        return -1;
855

    
856
    out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
857
    if (!out_buf)
858
        return -1;
859

    
860
    /* best compression, small window, no zlib header */
861
    memset(&strm, 0, sizeof(strm));
862
    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
863
                       Z_DEFLATED, -12, 
864
                       9, Z_DEFAULT_STRATEGY);
865
    if (ret != 0) {
866
        qemu_free(out_buf);
867
        return -1;
868
    }
869

    
870
    strm.avail_in = s->cluster_size;
871
    strm.next_in = (uint8_t *)buf;
872
    strm.avail_out = s->cluster_size;
873
    strm.next_out = out_buf;
874

    
875
    ret = deflate(&strm, Z_FINISH);
876
    if (ret != Z_STREAM_END && ret != Z_OK) {
877
        qemu_free(out_buf);
878
        deflateEnd(&strm);
879
        return -1;
880
    }
881
    out_len = strm.next_out - out_buf;
882

    
883
    deflateEnd(&strm);
884

    
885
    if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
886
        /* could not compress: write normal cluster */
887
        qcow_write(bs, sector_num, buf, s->cluster_sectors);
888
    } else {
889
        cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 
890
                                            out_len, 0, 0);
891
        cluster_offset &= s->cluster_offset_mask;
892
        if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
893
            qemu_free(out_buf);
894
            return -1;
895
        }
896
    }
897
    
898
    qemu_free(out_buf);
899
    return 0;
900
}
901

    
902
static void qcow_flush(BlockDriverState *bs)
903
{
904
    BDRVQcowState *s = bs->opaque;
905
    bdrv_flush(s->hd);
906
}
907

    
908
BlockDriver bdrv_qcow = {
909
    "qcow",
910
    sizeof(BDRVQcowState),
911
    qcow_probe,
912
    qcow_open,
913
    NULL,
914
    NULL,
915
    qcow_close,
916
    qcow_create,
917
    qcow_flush,
918
    qcow_is_allocated,
919
    qcow_set_key,
920
    qcow_make_empty,
921

    
922
    .bdrv_aio_new = qcow_aio_new,
923
    .bdrv_aio_read = qcow_aio_read,
924
    .bdrv_aio_write = qcow_aio_write,
925
    .bdrv_aio_cancel = qcow_aio_cancel,
926
    .bdrv_aio_delete = qcow_aio_delete,
927
};
928

    
929