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1
/*
2
 * Block driver for the QCOW version 2 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
#include "block/qcow2.h"
30
#include "qemu-error.h"
31

    
32
/*
33
  Differences with QCOW:
34

35
  - Support for multiple incremental snapshots.
36
  - Memory management by reference counts.
37
  - Clusters which have a reference count of one have the bit
38
    QCOW_OFLAG_COPIED to optimize write performance.
39
  - Size of compressed clusters is stored in sectors to reduce bit usage
40
    in the cluster offsets.
41
  - Support for storing additional data (such as the VM state) in the
42
    snapshots.
43
  - If a backing store is used, the cluster size is not constrained
44
    (could be backported to QCOW).
45
  - L2 tables have always a size of one cluster.
46
*/
47

    
48

    
49
typedef struct {
50
    uint32_t magic;
51
    uint32_t len;
52
} QCowExtension;
53
#define  QCOW_EXT_MAGIC_END 0
54
#define  QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
55

    
56
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
57
{
58
    const QCowHeader *cow_header = (const void *)buf;
59

    
60
    if (buf_size >= sizeof(QCowHeader) &&
61
        be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
62
        be32_to_cpu(cow_header->version) == QCOW_VERSION)
63
        return 100;
64
    else
65
        return 0;
66
}
67

    
68

    
69
/* 
70
 * read qcow2 extension and fill bs
71
 * start reading from start_offset
72
 * finish reading upon magic of value 0 or when end_offset reached
73
 * unknown magic is skipped (future extension this version knows nothing about)
74
 * return 0 upon success, non-0 otherwise
75
 */
76
static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset,
77
                                uint64_t end_offset)
78
{
79
    QCowExtension ext;
80
    uint64_t offset;
81

    
82
#ifdef DEBUG_EXT
83
    printf("qcow_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
84
#endif
85
    offset = start_offset;
86
    while (offset < end_offset) {
87

    
88
#ifdef DEBUG_EXT
89
        /* Sanity check */
90
        if (offset > s->cluster_size)
91
            printf("qcow_handle_extension: suspicious offset %lu\n", offset);
92

    
93
        printf("attemting to read extended header in offset %lu\n", offset);
94
#endif
95

    
96
        if (bdrv_pread(bs->file, offset, &ext, sizeof(ext)) != sizeof(ext)) {
97
            fprintf(stderr, "qcow_handle_extension: ERROR: "
98
                    "pread fail from offset %" PRIu64 "\n",
99
                    offset);
100
            return 1;
101
        }
102
        be32_to_cpus(&ext.magic);
103
        be32_to_cpus(&ext.len);
104
        offset += sizeof(ext);
105
#ifdef DEBUG_EXT
106
        printf("ext.magic = 0x%x\n", ext.magic);
107
#endif
108
        switch (ext.magic) {
109
        case QCOW_EXT_MAGIC_END:
110
            return 0;
111

    
112
        case QCOW_EXT_MAGIC_BACKING_FORMAT:
113
            if (ext.len >= sizeof(bs->backing_format)) {
114
                fprintf(stderr, "ERROR: ext_backing_format: len=%u too large"
115
                        " (>=%zu)\n",
116
                        ext.len, sizeof(bs->backing_format));
117
                return 2;
118
            }
119
            if (bdrv_pread(bs->file, offset , bs->backing_format,
120
                           ext.len) != ext.len)
121
                return 3;
122
            bs->backing_format[ext.len] = '\0';
123
#ifdef DEBUG_EXT
124
            printf("Qcow2: Got format extension %s\n", bs->backing_format);
125
#endif
126
            offset = ((offset + ext.len + 7) & ~7);
127
            break;
128

    
129
        default:
130
            /* unknown magic -- just skip it */
131
            offset = ((offset + ext.len + 7) & ~7);
132
            break;
133
        }
134
    }
135

    
136
    return 0;
137
}
138

    
139

    
140
static int qcow_open(BlockDriverState *bs, int flags)
141
{
142
    BDRVQcowState *s = bs->opaque;
143
    int len, i;
144
    QCowHeader header;
145
    uint64_t ext_end;
146

    
147
    if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header))
148
        goto fail;
149
    be32_to_cpus(&header.magic);
150
    be32_to_cpus(&header.version);
151
    be64_to_cpus(&header.backing_file_offset);
152
    be32_to_cpus(&header.backing_file_size);
153
    be64_to_cpus(&header.size);
154
    be32_to_cpus(&header.cluster_bits);
155
    be32_to_cpus(&header.crypt_method);
156
    be64_to_cpus(&header.l1_table_offset);
157
    be32_to_cpus(&header.l1_size);
158
    be64_to_cpus(&header.refcount_table_offset);
159
    be32_to_cpus(&header.refcount_table_clusters);
160
    be64_to_cpus(&header.snapshots_offset);
161
    be32_to_cpus(&header.nb_snapshots);
162

    
163
    if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
164
        goto fail;
165
    if (header.cluster_bits < MIN_CLUSTER_BITS ||
166
        header.cluster_bits > MAX_CLUSTER_BITS)
167
        goto fail;
168
    if (header.crypt_method > QCOW_CRYPT_AES)
169
        goto fail;
170
    s->crypt_method_header = header.crypt_method;
171
    if (s->crypt_method_header)
172
        bs->encrypted = 1;
173
    s->cluster_bits = header.cluster_bits;
174
    s->cluster_size = 1 << s->cluster_bits;
175
    s->cluster_sectors = 1 << (s->cluster_bits - 9);
176
    s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
177
    s->l2_size = 1 << s->l2_bits;
178
    bs->total_sectors = header.size / 512;
179
    s->csize_shift = (62 - (s->cluster_bits - 8));
180
    s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
181
    s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
182
    s->refcount_table_offset = header.refcount_table_offset;
183
    s->refcount_table_size =
184
        header.refcount_table_clusters << (s->cluster_bits - 3);
185

    
186
    s->snapshots_offset = header.snapshots_offset;
187
    s->nb_snapshots = header.nb_snapshots;
188

    
189
    /* read the level 1 table */
190
    s->l1_size = header.l1_size;
191
    s->l1_vm_state_index = size_to_l1(s, header.size);
192
    /* the L1 table must contain at least enough entries to put
193
       header.size bytes */
194
    if (s->l1_size < s->l1_vm_state_index)
195
        goto fail;
196
    s->l1_table_offset = header.l1_table_offset;
197
    if (s->l1_size > 0) {
198
        s->l1_table = qemu_mallocz(
199
            align_offset(s->l1_size * sizeof(uint64_t), 512));
200
        if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
201
            s->l1_size * sizeof(uint64_t))
202
            goto fail;
203
        for(i = 0;i < s->l1_size; i++) {
204
            be64_to_cpus(&s->l1_table[i]);
205
        }
206
    }
207
    /* alloc L2 cache */
208
    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
209
    s->cluster_cache = qemu_malloc(s->cluster_size);
210
    /* one more sector for decompressed data alignment */
211
    s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
212
                                  + 512);
213
    s->cluster_cache_offset = -1;
214

    
215
    if (qcow2_refcount_init(bs) < 0)
216
        goto fail;
217

    
218
    QLIST_INIT(&s->cluster_allocs);
219

    
220
    /* read qcow2 extensions */
221
    if (header.backing_file_offset)
222
        ext_end = header.backing_file_offset;
223
    else
224
        ext_end = s->cluster_size;
225
    if (qcow_read_extensions(bs, sizeof(header), ext_end))
226
        goto fail;
227

    
228
    /* read the backing file name */
229
    if (header.backing_file_offset != 0) {
230
        len = header.backing_file_size;
231
        if (len > 1023)
232
            len = 1023;
233
        if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len)
234
            goto fail;
235
        bs->backing_file[len] = '\0';
236
    }
237
    if (qcow2_read_snapshots(bs) < 0)
238
        goto fail;
239

    
240
#ifdef DEBUG_ALLOC
241
    qcow2_check_refcounts(bs);
242
#endif
243
    return 0;
244

    
245
 fail:
246
    qcow2_free_snapshots(bs);
247
    qcow2_refcount_close(bs);
248
    qemu_free(s->l1_table);
249
    qemu_free(s->l2_cache);
250
    qemu_free(s->cluster_cache);
251
    qemu_free(s->cluster_data);
252
    return -1;
253
}
254

    
255
static int qcow_set_key(BlockDriverState *bs, const char *key)
256
{
257
    BDRVQcowState *s = bs->opaque;
258
    uint8_t keybuf[16];
259
    int len, i;
260

    
261
    memset(keybuf, 0, 16);
262
    len = strlen(key);
263
    if (len > 16)
264
        len = 16;
265
    /* XXX: we could compress the chars to 7 bits to increase
266
       entropy */
267
    for(i = 0;i < len;i++) {
268
        keybuf[i] = key[i];
269
    }
270
    s->crypt_method = s->crypt_method_header;
271

    
272
    if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
273
        return -1;
274
    if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
275
        return -1;
276
#if 0
277
    /* test */
278
    {
279
        uint8_t in[16];
280
        uint8_t out[16];
281
        uint8_t tmp[16];
282
        for(i=0;i<16;i++)
283
            in[i] = i;
284
        AES_encrypt(in, tmp, &s->aes_encrypt_key);
285
        AES_decrypt(tmp, out, &s->aes_decrypt_key);
286
        for(i = 0; i < 16; i++)
287
            printf(" %02x", tmp[i]);
288
        printf("\n");
289
        for(i = 0; i < 16; i++)
290
            printf(" %02x", out[i]);
291
        printf("\n");
292
    }
293
#endif
294
    return 0;
295
}
296

    
297
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
298
                             int nb_sectors, int *pnum)
299
{
300
    uint64_t cluster_offset;
301
    int ret;
302

    
303
    *pnum = nb_sectors;
304
    /* FIXME We can get errors here, but the bdrv_is_allocated interface can't
305
     * pass them on today */
306
    ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
307
    if (ret < 0) {
308
        *pnum = 0;
309
    }
310

    
311
    return (cluster_offset != 0);
312
}
313

    
314
/* handle reading after the end of the backing file */
315
int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
316
                  int64_t sector_num, int nb_sectors)
317
{
318
    int n1;
319
    if ((sector_num + nb_sectors) <= bs->total_sectors)
320
        return nb_sectors;
321
    if (sector_num >= bs->total_sectors)
322
        n1 = 0;
323
    else
324
        n1 = bs->total_sectors - sector_num;
325

    
326
    qemu_iovec_memset(qiov, 0, 512 * (nb_sectors - n1));
327

    
328
    return n1;
329
}
330

    
331
typedef struct QCowAIOCB {
332
    BlockDriverAIOCB common;
333
    int64_t sector_num;
334
    QEMUIOVector *qiov;
335
    int remaining_sectors;
336
    int cur_nr_sectors;        /* number of sectors in current iteration */
337
    uint64_t bytes_done;
338
    uint64_t cluster_offset;
339
    uint8_t *cluster_data;
340
    BlockDriverAIOCB *hd_aiocb;
341
    QEMUIOVector hd_qiov;
342
    QEMUBH *bh;
343
    QCowL2Meta l2meta;
344
    QLIST_ENTRY(QCowAIOCB) next_depend;
345
} QCowAIOCB;
346

    
347
static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
348
{
349
    QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common);
350
    if (acb->hd_aiocb)
351
        bdrv_aio_cancel(acb->hd_aiocb);
352
    qemu_aio_release(acb);
353
}
354

    
355
static AIOPool qcow_aio_pool = {
356
    .aiocb_size         = sizeof(QCowAIOCB),
357
    .cancel             = qcow_aio_cancel,
358
};
359

    
360
static void qcow_aio_read_cb(void *opaque, int ret);
361
static void qcow_aio_read_bh(void *opaque)
362
{
363
    QCowAIOCB *acb = opaque;
364
    qemu_bh_delete(acb->bh);
365
    acb->bh = NULL;
366
    qcow_aio_read_cb(opaque, 0);
367
}
368

    
369
static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
370
{
371
    if (acb->bh)
372
        return -EIO;
373

    
374
    acb->bh = qemu_bh_new(cb, acb);
375
    if (!acb->bh)
376
        return -EIO;
377

    
378
    qemu_bh_schedule(acb->bh);
379

    
380
    return 0;
381
}
382

    
383
static void qcow_aio_read_cb(void *opaque, int ret)
384
{
385
    QCowAIOCB *acb = opaque;
386
    BlockDriverState *bs = acb->common.bs;
387
    BDRVQcowState *s = bs->opaque;
388
    int index_in_cluster, n1;
389

    
390
    acb->hd_aiocb = NULL;
391
    if (ret < 0)
392
        goto done;
393

    
394
    /* post process the read buffer */
395
    if (!acb->cluster_offset) {
396
        /* nothing to do */
397
    } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
398
        /* nothing to do */
399
    } else {
400
        if (s->crypt_method) {
401
            qcow2_encrypt_sectors(s, acb->sector_num,  acb->cluster_data,
402
                acb->cluster_data, acb->cur_nr_sectors, 0, &s->aes_decrypt_key);
403
            qemu_iovec_reset(&acb->hd_qiov);
404
            qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done,
405
                acb->cur_nr_sectors * 512);
406
            qemu_iovec_from_buffer(&acb->hd_qiov, acb->cluster_data,
407
                512 * acb->cur_nr_sectors);
408
        }
409
    }
410

    
411
    acb->remaining_sectors -= acb->cur_nr_sectors;
412
    acb->sector_num += acb->cur_nr_sectors;
413
    acb->bytes_done += acb->cur_nr_sectors * 512;
414

    
415
    if (acb->remaining_sectors == 0) {
416
        /* request completed */
417
        ret = 0;
418
        goto done;
419
    }
420

    
421
    /* prepare next AIO request */
422
    acb->cur_nr_sectors = acb->remaining_sectors;
423
    if (s->crypt_method) {
424
        acb->cur_nr_sectors = MIN(acb->cur_nr_sectors,
425
            QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
426
    }
427

    
428
    ret = qcow2_get_cluster_offset(bs, acb->sector_num << 9,
429
        &acb->cur_nr_sectors, &acb->cluster_offset);
430
    if (ret < 0) {
431
        goto done;
432
    }
433

    
434
    index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
435

    
436
    qemu_iovec_reset(&acb->hd_qiov);
437
    qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done,
438
        acb->cur_nr_sectors * 512);
439

    
440
    if (!acb->cluster_offset) {
441

    
442
        if (bs->backing_hd) {
443
            /* read from the base image */
444
            n1 = qcow2_backing_read1(bs->backing_hd, &acb->hd_qiov,
445
                acb->sector_num, acb->cur_nr_sectors);
446
            if (n1 > 0) {
447
                BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
448
                acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
449
                                    &acb->hd_qiov, acb->cur_nr_sectors,
450
                                    qcow_aio_read_cb, acb);
451
                if (acb->hd_aiocb == NULL)
452
                    goto done;
453
            } else {
454
                ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
455
                if (ret < 0)
456
                    goto done;
457
            }
458
        } else {
459
            /* Note: in this case, no need to wait */
460
            qemu_iovec_memset(&acb->hd_qiov, 0, 512 * acb->cur_nr_sectors);
461
            ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
462
            if (ret < 0)
463
                goto done;
464
        }
465
    } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
466
        /* add AIO support for compressed blocks ? */
467
        if (qcow2_decompress_cluster(bs, acb->cluster_offset) < 0)
468
            goto done;
469

    
470
        qemu_iovec_from_buffer(&acb->hd_qiov,
471
            s->cluster_cache + index_in_cluster * 512,
472
            512 * acb->cur_nr_sectors);
473

    
474
        ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
475
        if (ret < 0)
476
            goto done;
477
    } else {
478
        if ((acb->cluster_offset & 511) != 0) {
479
            ret = -EIO;
480
            goto done;
481
        }
482

    
483
        if (s->crypt_method) {
484
            /*
485
             * For encrypted images, read everything into a temporary
486
             * contiguous buffer on which the AES functions can work.
487
             */
488
            if (!acb->cluster_data) {
489
                acb->cluster_data =
490
                    qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
491
            }
492

    
493
            assert(acb->cur_nr_sectors <=
494
                QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
495
            qemu_iovec_reset(&acb->hd_qiov);
496
            qemu_iovec_add(&acb->hd_qiov, acb->cluster_data,
497
                512 * acb->cur_nr_sectors);
498
        }
499

    
500
        BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
501
        acb->hd_aiocb = bdrv_aio_readv(bs->file,
502
                            (acb->cluster_offset >> 9) + index_in_cluster,
503
                            &acb->hd_qiov, acb->cur_nr_sectors,
504
                            qcow_aio_read_cb, acb);
505
        if (acb->hd_aiocb == NULL) {
506
            ret = -EIO;
507
            goto done;
508
        }
509
    }
510

    
511
    return;
512
done:
513
    acb->common.cb(acb->common.opaque, ret);
514
    qemu_iovec_destroy(&acb->hd_qiov);
515
    qemu_aio_release(acb);
516
}
517

    
518
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
519
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
520
        BlockDriverCompletionFunc *cb, void *opaque, int is_write)
521
{
522
    QCowAIOCB *acb;
523

    
524
    acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
525
    if (!acb)
526
        return NULL;
527
    acb->hd_aiocb = NULL;
528
    acb->sector_num = sector_num;
529
    acb->qiov = qiov;
530

    
531
    qemu_iovec_init(&acb->hd_qiov, qiov->niov);
532

    
533
    acb->bytes_done = 0;
534
    acb->remaining_sectors = nb_sectors;
535
    acb->cur_nr_sectors = 0;
536
    acb->cluster_offset = 0;
537
    acb->l2meta.nb_clusters = 0;
538
    QLIST_INIT(&acb->l2meta.dependent_requests);
539
    return acb;
540
}
541

    
542
static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
543
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
544
        BlockDriverCompletionFunc *cb, void *opaque)
545
{
546
    QCowAIOCB *acb;
547

    
548
    acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
549
    if (!acb)
550
        return NULL;
551

    
552
    qcow_aio_read_cb(acb, 0);
553
    return &acb->common;
554
}
555

    
556
static void qcow_aio_write_cb(void *opaque, int ret);
557

    
558
static void run_dependent_requests(QCowL2Meta *m)
559
{
560
    QCowAIOCB *req;
561
    QCowAIOCB *next;
562

    
563
    /* Take the request off the list of running requests */
564
    if (m->nb_clusters != 0) {
565
        QLIST_REMOVE(m, next_in_flight);
566
    }
567

    
568
    /* Restart all dependent requests */
569
    QLIST_FOREACH_SAFE(req, &m->dependent_requests, next_depend, next) {
570
        qcow_aio_write_cb(req, 0);
571
    }
572

    
573
    /* Empty the list for the next part of the request */
574
    QLIST_INIT(&m->dependent_requests);
575
}
576

    
577
static void qcow_aio_write_cb(void *opaque, int ret)
578
{
579
    QCowAIOCB *acb = opaque;
580
    BlockDriverState *bs = acb->common.bs;
581
    BDRVQcowState *s = bs->opaque;
582
    int index_in_cluster;
583
    int n_end;
584

    
585
    acb->hd_aiocb = NULL;
586

    
587
    if (ret >= 0) {
588
        ret = qcow2_alloc_cluster_link_l2(bs, &acb->l2meta);
589
    }
590

    
591
    run_dependent_requests(&acb->l2meta);
592

    
593
    if (ret < 0)
594
        goto done;
595

    
596
    acb->remaining_sectors -= acb->cur_nr_sectors;
597
    acb->sector_num += acb->cur_nr_sectors;
598
    acb->bytes_done += acb->cur_nr_sectors * 512;
599

    
600
    if (acb->remaining_sectors == 0) {
601
        /* request completed */
602
        ret = 0;
603
        goto done;
604
    }
605

    
606
    index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
607
    n_end = index_in_cluster + acb->remaining_sectors;
608
    if (s->crypt_method &&
609
        n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
610
        n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
611

    
612
    ret = qcow2_alloc_cluster_offset(bs, acb->sector_num << 9,
613
        index_in_cluster, n_end, &acb->cur_nr_sectors, &acb->l2meta);
614
    if (ret < 0) {
615
        goto done;
616
    }
617

    
618
    acb->cluster_offset = acb->l2meta.cluster_offset;
619

    
620
    /* Need to wait for another request? If so, we are done for now. */
621
    if (acb->l2meta.nb_clusters == 0 && acb->l2meta.depends_on != NULL) {
622
        QLIST_INSERT_HEAD(&acb->l2meta.depends_on->dependent_requests,
623
            acb, next_depend);
624
        return;
625
    }
626

    
627
    assert((acb->cluster_offset & 511) == 0);
628

    
629
    qemu_iovec_reset(&acb->hd_qiov);
630
    qemu_iovec_copy(&acb->hd_qiov, acb->qiov, acb->bytes_done,
631
        acb->cur_nr_sectors * 512);
632

    
633
    if (s->crypt_method) {
634
        if (!acb->cluster_data) {
635
            acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
636
                                             s->cluster_size);
637
        }
638

    
639
        assert(acb->hd_qiov.size <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
640
        qemu_iovec_to_buffer(&acb->hd_qiov, acb->cluster_data);
641

    
642
        qcow2_encrypt_sectors(s, acb->sector_num, acb->cluster_data,
643
            acb->cluster_data, acb->cur_nr_sectors, 1, &s->aes_encrypt_key);
644

    
645
        qemu_iovec_reset(&acb->hd_qiov);
646
        qemu_iovec_add(&acb->hd_qiov, acb->cluster_data,
647
            acb->cur_nr_sectors * 512);
648
    }
649

    
650
    BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
651
    acb->hd_aiocb = bdrv_aio_writev(bs->file,
652
                                    (acb->cluster_offset >> 9) + index_in_cluster,
653
                                    &acb->hd_qiov, acb->cur_nr_sectors,
654
                                    qcow_aio_write_cb, acb);
655
    if (acb->hd_aiocb == NULL) {
656
        ret = -EIO;
657
        goto fail;
658
    }
659

    
660
    return;
661

    
662
fail:
663
    if (acb->l2meta.nb_clusters != 0) {
664
        QLIST_REMOVE(&acb->l2meta, next_in_flight);
665
    }
666
done:
667
    acb->common.cb(acb->common.opaque, ret);
668
    qemu_iovec_destroy(&acb->hd_qiov);
669
    qemu_aio_release(acb);
670
}
671

    
672
static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
673
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
674
        BlockDriverCompletionFunc *cb, void *opaque)
675
{
676
    BDRVQcowState *s = bs->opaque;
677
    QCowAIOCB *acb;
678

    
679
    s->cluster_cache_offset = -1; /* disable compressed cache */
680

    
681
    acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
682
    if (!acb)
683
        return NULL;
684

    
685
    qcow_aio_write_cb(acb, 0);
686
    return &acb->common;
687
}
688

    
689
static void qcow_close(BlockDriverState *bs)
690
{
691
    BDRVQcowState *s = bs->opaque;
692
    qemu_free(s->l1_table);
693
    qemu_free(s->l2_cache);
694
    qemu_free(s->cluster_cache);
695
    qemu_free(s->cluster_data);
696
    qcow2_refcount_close(bs);
697
}
698

    
699
/*
700
 * Updates the variable length parts of the qcow2 header, i.e. the backing file
701
 * name and all extensions. qcow2 was not designed to allow such changes, so if
702
 * we run out of space (we can only use the first cluster) this function may
703
 * fail.
704
 *
705
 * Returns 0 on success, -errno in error cases.
706
 */
707
static int qcow2_update_ext_header(BlockDriverState *bs,
708
    const char *backing_file, const char *backing_fmt)
709
{
710
    size_t backing_file_len = 0;
711
    size_t backing_fmt_len = 0;
712
    BDRVQcowState *s = bs->opaque;
713
    QCowExtension ext_backing_fmt = {0, 0};
714
    int ret;
715

    
716
    /* Backing file format doesn't make sense without a backing file */
717
    if (backing_fmt && !backing_file) {
718
        return -EINVAL;
719
    }
720

    
721
    /* Prepare the backing file format extension if needed */
722
    if (backing_fmt) {
723
        ext_backing_fmt.len = cpu_to_be32(strlen(backing_fmt));
724
        ext_backing_fmt.magic = cpu_to_be32(QCOW_EXT_MAGIC_BACKING_FORMAT);
725
        backing_fmt_len = ((sizeof(ext_backing_fmt)
726
            + strlen(backing_fmt) + 7) & ~7);
727
    }
728

    
729
    /* Check if we can fit the new header into the first cluster */
730
    if (backing_file) {
731
        backing_file_len = strlen(backing_file);
732
    }
733

    
734
    size_t header_size = sizeof(QCowHeader) + backing_file_len
735
        + backing_fmt_len;
736

    
737
    if (header_size > s->cluster_size) {
738
        return -ENOSPC;
739
    }
740

    
741
    /* Rewrite backing file name and qcow2 extensions */
742
    size_t ext_size = header_size - sizeof(QCowHeader);
743
    uint8_t buf[ext_size];
744
    size_t offset = 0;
745
    size_t backing_file_offset = 0;
746

    
747
    if (backing_file) {
748
        if (backing_fmt) {
749
            int padding = backing_fmt_len -
750
                (sizeof(ext_backing_fmt) + strlen(backing_fmt));
751

    
752
            memcpy(buf + offset, &ext_backing_fmt, sizeof(ext_backing_fmt));
753
            offset += sizeof(ext_backing_fmt);
754

    
755
            memcpy(buf + offset, backing_fmt, strlen(backing_fmt));
756
            offset += strlen(backing_fmt);
757

    
758
            memset(buf + offset, 0, padding);
759
            offset += padding;
760
        }
761

    
762
        memcpy(buf + offset, backing_file, backing_file_len);
763
        backing_file_offset = sizeof(QCowHeader) + offset;
764
    }
765

    
766
    ret = bdrv_pwrite_sync(bs->file, sizeof(QCowHeader), buf, ext_size);
767
    if (ret < 0) {
768
        goto fail;
769
    }
770

    
771
    /* Update header fields */
772
    uint64_t be_backing_file_offset = cpu_to_be64(backing_file_offset);
773
    uint32_t be_backing_file_size = cpu_to_be32(backing_file_len);
774

    
775
    ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_offset),
776
        &be_backing_file_offset, sizeof(uint64_t));
777
    if (ret < 0) {
778
        goto fail;
779
    }
780

    
781
    ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, backing_file_size),
782
        &be_backing_file_size, sizeof(uint32_t));
783
    if (ret < 0) {
784
        goto fail;
785
    }
786

    
787
    ret = 0;
788
fail:
789
    return ret;
790
}
791

    
792
static int qcow2_change_backing_file(BlockDriverState *bs,
793
    const char *backing_file, const char *backing_fmt)
794
{
795
    return qcow2_update_ext_header(bs, backing_file, backing_fmt);
796
}
797

    
798
static int preallocate(BlockDriverState *bs)
799
{
800
    uint64_t nb_sectors;
801
    uint64_t offset;
802
    int num;
803
    int ret;
804
    QCowL2Meta meta;
805

    
806
    nb_sectors = bdrv_getlength(bs) >> 9;
807
    offset = 0;
808
    QLIST_INIT(&meta.dependent_requests);
809
    meta.cluster_offset = 0;
810

    
811
    while (nb_sectors) {
812
        num = MIN(nb_sectors, INT_MAX >> 9);
813
        ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, &meta);
814
        if (ret < 0) {
815
            return ret;
816
        }
817

    
818
        ret = qcow2_alloc_cluster_link_l2(bs, &meta);
819
        if (ret < 0) {
820
            qcow2_free_any_clusters(bs, meta.cluster_offset, meta.nb_clusters);
821
            return ret;
822
        }
823

    
824
        /* There are no dependent requests, but we need to remove our request
825
         * from the list of in-flight requests */
826
        run_dependent_requests(&meta);
827

    
828
        /* TODO Preallocate data if requested */
829

    
830
        nb_sectors -= num;
831
        offset += num << 9;
832
    }
833

    
834
    /*
835
     * It is expected that the image file is large enough to actually contain
836
     * all of the allocated clusters (otherwise we get failing reads after
837
     * EOF). Extend the image to the last allocated sector.
838
     */
839
    if (meta.cluster_offset != 0) {
840
        uint8_t buf[512];
841
        memset(buf, 0, 512);
842
        ret = bdrv_write(bs->file, (meta.cluster_offset >> 9) + num - 1, buf, 1);
843
        if (ret < 0) {
844
            return ret;
845
        }
846
    }
847

    
848
    return 0;
849
}
850

    
851
static int qcow_create2(const char *filename, int64_t total_size,
852
                        const char *backing_file, const char *backing_format,
853
                        int flags, size_t cluster_size, int prealloc,
854
                        QEMUOptionParameter *options)
855
{
856
    /* Calulate cluster_bits */
857
    int cluster_bits;
858
    cluster_bits = ffs(cluster_size) - 1;
859
    if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
860
        (1 << cluster_bits) != cluster_size)
861
    {
862
        error_report(
863
            "Cluster size must be a power of two between %d and %dk\n",
864
            1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
865
        return -EINVAL;
866
    }
867

    
868
    /*
869
     * Open the image file and write a minimal qcow2 header.
870
     *
871
     * We keep things simple and start with a zero-sized image. We also
872
     * do without refcount blocks or a L1 table for now. We'll fix the
873
     * inconsistency later.
874
     *
875
     * We do need a refcount table because growing the refcount table means
876
     * allocating two new refcount blocks - the seconds of which would be at
877
     * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
878
     * size for any qcow2 image.
879
     */
880
    BlockDriverState* bs;
881
    QCowHeader header;
882
    uint8_t* refcount_table;
883
    int ret;
884

    
885
    ret = bdrv_create_file(filename, options);
886
    if (ret < 0) {
887
        return ret;
888
    }
889

    
890
    ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR);
891
    if (ret < 0) {
892
        return ret;
893
    }
894

    
895
    /* Write the header */
896
    memset(&header, 0, sizeof(header));
897
    header.magic = cpu_to_be32(QCOW_MAGIC);
898
    header.version = cpu_to_be32(QCOW_VERSION);
899
    header.cluster_bits = cpu_to_be32(cluster_bits);
900
    header.size = cpu_to_be64(0);
901
    header.l1_table_offset = cpu_to_be64(0);
902
    header.l1_size = cpu_to_be32(0);
903
    header.refcount_table_offset = cpu_to_be64(cluster_size);
904
    header.refcount_table_clusters = cpu_to_be32(1);
905

    
906
    if (flags & BLOCK_FLAG_ENCRYPT) {
907
        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
908
    } else {
909
        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
910
    }
911

    
912
    ret = bdrv_pwrite(bs, 0, &header, sizeof(header));
913
    if (ret < 0) {
914
        goto out;
915
    }
916

    
917
    /* Write an empty refcount table */
918
    refcount_table = qemu_mallocz(cluster_size);
919
    ret = bdrv_pwrite(bs, cluster_size, refcount_table, cluster_size);
920
    qemu_free(refcount_table);
921

    
922
    if (ret < 0) {
923
        goto out;
924
    }
925

    
926
    bdrv_close(bs);
927

    
928
    /*
929
     * And now open the image and make it consistent first (i.e. increase the
930
     * refcount of the cluster that is occupied by the header and the refcount
931
     * table)
932
     */
933
    BlockDriver* drv = bdrv_find_format("qcow2");
934
    assert(drv != NULL);
935
    ret = bdrv_open(bs, filename, BDRV_O_RDWR | BDRV_O_NO_FLUSH, drv);
936
    if (ret < 0) {
937
        goto out;
938
    }
939

    
940
    ret = qcow2_alloc_clusters(bs, 2 * cluster_size);
941
    if (ret < 0) {
942
        goto out;
943

    
944
    } else if (ret != 0) {
945
        error_report("Huh, first cluster in empty image is already in use?");
946
        abort();
947
    }
948

    
949
    /* Okay, now that we have a valid image, let's give it the right size */
950
    ret = bdrv_truncate(bs, total_size * BDRV_SECTOR_SIZE);
951
    if (ret < 0) {
952
        goto out;
953
    }
954

    
955
    /* Want a backing file? There you go.*/
956
    if (backing_file) {
957
        ret = bdrv_change_backing_file(bs, backing_file, backing_format);
958
        if (ret < 0) {
959
            goto out;
960
        }
961
    }
962

    
963
    /* And if we're supposed to preallocate metadata, do that now */
964
    if (prealloc) {
965
        ret = preallocate(bs);
966
        if (ret < 0) {
967
            goto out;
968
        }
969
    }
970

    
971
    ret = 0;
972
out:
973
    bdrv_delete(bs);
974
    return ret;
975
}
976

    
977
static int qcow_create(const char *filename, QEMUOptionParameter *options)
978
{
979
    const char *backing_file = NULL;
980
    const char *backing_fmt = NULL;
981
    uint64_t sectors = 0;
982
    int flags = 0;
983
    size_t cluster_size = 65536;
984
    int prealloc = 0;
985

    
986
    /* Read out options */
987
    while (options && options->name) {
988
        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
989
            sectors = options->value.n / 512;
990
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
991
            backing_file = options->value.s;
992
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
993
            backing_fmt = options->value.s;
994
        } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
995
            flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
996
        } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
997
            if (options->value.n) {
998
                cluster_size = options->value.n;
999
            }
1000
        } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) {
1001
            if (!options->value.s || !strcmp(options->value.s, "off")) {
1002
                prealloc = 0;
1003
            } else if (!strcmp(options->value.s, "metadata")) {
1004
                prealloc = 1;
1005
            } else {
1006
                fprintf(stderr, "Invalid preallocation mode: '%s'\n",
1007
                    options->value.s);
1008
                return -EINVAL;
1009
            }
1010
        }
1011
        options++;
1012
    }
1013

    
1014
    if (backing_file && prealloc) {
1015
        fprintf(stderr, "Backing file and preallocation cannot be used at "
1016
            "the same time\n");
1017
        return -EINVAL;
1018
    }
1019

    
1020
    return qcow_create2(filename, sectors, backing_file, backing_fmt, flags,
1021
        cluster_size, prealloc, options);
1022
}
1023

    
1024
static int qcow_make_empty(BlockDriverState *bs)
1025
{
1026
#if 0
1027
    /* XXX: not correct */
1028
    BDRVQcowState *s = bs->opaque;
1029
    uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1030
    int ret;
1031

1032
    memset(s->l1_table, 0, l1_length);
1033
    if (bdrv_pwrite(bs->file, s->l1_table_offset, s->l1_table, l1_length) < 0)
1034
        return -1;
1035
    ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
1036
    if (ret < 0)
1037
        return ret;
1038

1039
    l2_cache_reset(bs);
1040
#endif
1041
    return 0;
1042
}
1043

    
1044
static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
1045
{
1046
    BDRVQcowState *s = bs->opaque;
1047
    int ret, new_l1_size;
1048

    
1049
    if (offset & 511) {
1050
        return -EINVAL;
1051
    }
1052

    
1053
    /* cannot proceed if image has snapshots */
1054
    if (s->nb_snapshots) {
1055
        return -ENOTSUP;
1056
    }
1057

    
1058
    /* shrinking is currently not supported */
1059
    if (offset < bs->total_sectors * 512) {
1060
        return -ENOTSUP;
1061
    }
1062

    
1063
    new_l1_size = size_to_l1(s, offset);
1064
    ret = qcow2_grow_l1_table(bs, new_l1_size, true);
1065
    if (ret < 0) {
1066
        return ret;
1067
    }
1068

    
1069
    /* write updated header.size */
1070
    offset = cpu_to_be64(offset);
1071
    ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
1072
                           &offset, sizeof(uint64_t));
1073
    if (ret < 0) {
1074
        return ret;
1075
    }
1076

    
1077
    s->l1_vm_state_index = new_l1_size;
1078
    return 0;
1079
}
1080

    
1081
/* XXX: put compressed sectors first, then all the cluster aligned
1082
   tables to avoid losing bytes in alignment */
1083
static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
1084
                                 const uint8_t *buf, int nb_sectors)
1085
{
1086
    BDRVQcowState *s = bs->opaque;
1087
    z_stream strm;
1088
    int ret, out_len;
1089
    uint8_t *out_buf;
1090
    uint64_t cluster_offset;
1091

    
1092
    if (nb_sectors == 0) {
1093
        /* align end of file to a sector boundary to ease reading with
1094
           sector based I/Os */
1095
        cluster_offset = bdrv_getlength(bs->file);
1096
        cluster_offset = (cluster_offset + 511) & ~511;
1097
        bdrv_truncate(bs->file, cluster_offset);
1098
        return 0;
1099
    }
1100

    
1101
    if (nb_sectors != s->cluster_sectors)
1102
        return -EINVAL;
1103

    
1104
    out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
1105

    
1106
    /* best compression, small window, no zlib header */
1107
    memset(&strm, 0, sizeof(strm));
1108
    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1109
                       Z_DEFLATED, -12,
1110
                       9, Z_DEFAULT_STRATEGY);
1111
    if (ret != 0) {
1112
        qemu_free(out_buf);
1113
        return -1;
1114
    }
1115

    
1116
    strm.avail_in = s->cluster_size;
1117
    strm.next_in = (uint8_t *)buf;
1118
    strm.avail_out = s->cluster_size;
1119
    strm.next_out = out_buf;
1120

    
1121
    ret = deflate(&strm, Z_FINISH);
1122
    if (ret != Z_STREAM_END && ret != Z_OK) {
1123
        qemu_free(out_buf);
1124
        deflateEnd(&strm);
1125
        return -1;
1126
    }
1127
    out_len = strm.next_out - out_buf;
1128

    
1129
    deflateEnd(&strm);
1130

    
1131
    if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1132
        /* could not compress: write normal cluster */
1133
        bdrv_write(bs, sector_num, buf, s->cluster_sectors);
1134
    } else {
1135
        cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
1136
            sector_num << 9, out_len);
1137
        if (!cluster_offset)
1138
            return -1;
1139
        cluster_offset &= s->cluster_offset_mask;
1140
        BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1141
        if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
1142
            qemu_free(out_buf);
1143
            return -1;
1144
        }
1145
    }
1146

    
1147
    qemu_free(out_buf);
1148
    return 0;
1149
}
1150

    
1151
static int qcow_flush(BlockDriverState *bs)
1152
{
1153
    return bdrv_flush(bs->file);
1154
}
1155

    
1156
static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs,
1157
         BlockDriverCompletionFunc *cb, void *opaque)
1158
{
1159
    return bdrv_aio_flush(bs->file, cb, opaque);
1160
}
1161

    
1162
static int64_t qcow_vm_state_offset(BDRVQcowState *s)
1163
{
1164
        return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
1165
}
1166

    
1167
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1168
{
1169
    BDRVQcowState *s = bs->opaque;
1170
    bdi->cluster_size = s->cluster_size;
1171
    bdi->vm_state_offset = qcow_vm_state_offset(s);
1172
    return 0;
1173
}
1174

    
1175

    
1176
static int qcow_check(BlockDriverState *bs, BdrvCheckResult *result)
1177
{
1178
    return qcow2_check_refcounts(bs, result);
1179
}
1180

    
1181
#if 0
1182
static void dump_refcounts(BlockDriverState *bs)
1183
{
1184
    BDRVQcowState *s = bs->opaque;
1185
    int64_t nb_clusters, k, k1, size;
1186
    int refcount;
1187

1188
    size = bdrv_getlength(bs->file);
1189
    nb_clusters = size_to_clusters(s, size);
1190
    for(k = 0; k < nb_clusters;) {
1191
        k1 = k;
1192
        refcount = get_refcount(bs, k);
1193
        k++;
1194
        while (k < nb_clusters && get_refcount(bs, k) == refcount)
1195
            k++;
1196
        printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
1197
               k - k1);
1198
    }
1199
}
1200
#endif
1201

    
1202
static int qcow_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
1203
                           int64_t pos, int size)
1204
{
1205
    BDRVQcowState *s = bs->opaque;
1206
    int growable = bs->growable;
1207
    int ret;
1208

    
1209
    BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
1210
    bs->growable = 1;
1211
    ret = bdrv_pwrite(bs, qcow_vm_state_offset(s) + pos, buf, size);
1212
    bs->growable = growable;
1213

    
1214
    return ret;
1215
}
1216

    
1217
static int qcow_load_vmstate(BlockDriverState *bs, uint8_t *buf,
1218
                           int64_t pos, int size)
1219
{
1220
    BDRVQcowState *s = bs->opaque;
1221
    int growable = bs->growable;
1222
    int ret;
1223

    
1224
    BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
1225
    bs->growable = 1;
1226
    ret = bdrv_pread(bs, qcow_vm_state_offset(s) + pos, buf, size);
1227
    bs->growable = growable;
1228

    
1229
    return ret;
1230
}
1231

    
1232
static QEMUOptionParameter qcow_create_options[] = {
1233
    {
1234
        .name = BLOCK_OPT_SIZE,
1235
        .type = OPT_SIZE,
1236
        .help = "Virtual disk size"
1237
    },
1238
    {
1239
        .name = BLOCK_OPT_BACKING_FILE,
1240
        .type = OPT_STRING,
1241
        .help = "File name of a base image"
1242
    },
1243
    {
1244
        .name = BLOCK_OPT_BACKING_FMT,
1245
        .type = OPT_STRING,
1246
        .help = "Image format of the base image"
1247
    },
1248
    {
1249
        .name = BLOCK_OPT_ENCRYPT,
1250
        .type = OPT_FLAG,
1251
        .help = "Encrypt the image"
1252
    },
1253
    {
1254
        .name = BLOCK_OPT_CLUSTER_SIZE,
1255
        .type = OPT_SIZE,
1256
        .help = "qcow2 cluster size"
1257
    },
1258
    {
1259
        .name = BLOCK_OPT_PREALLOC,
1260
        .type = OPT_STRING,
1261
        .help = "Preallocation mode (allowed values: off, metadata)"
1262
    },
1263
    { NULL }
1264
};
1265

    
1266
static BlockDriver bdrv_qcow2 = {
1267
    .format_name        = "qcow2",
1268
    .instance_size        = sizeof(BDRVQcowState),
1269
    .bdrv_probe                = qcow_probe,
1270
    .bdrv_open                = qcow_open,
1271
    .bdrv_close                = qcow_close,
1272
    .bdrv_create        = qcow_create,
1273
    .bdrv_flush                = qcow_flush,
1274
    .bdrv_is_allocated        = qcow_is_allocated,
1275
    .bdrv_set_key        = qcow_set_key,
1276
    .bdrv_make_empty        = qcow_make_empty,
1277

    
1278
    .bdrv_aio_readv        = qcow_aio_readv,
1279
    .bdrv_aio_writev        = qcow_aio_writev,
1280
    .bdrv_aio_flush        = qcow_aio_flush,
1281

    
1282
    .bdrv_truncate          = qcow2_truncate,
1283
    .bdrv_write_compressed  = qcow_write_compressed,
1284

    
1285
    .bdrv_snapshot_create   = qcow2_snapshot_create,
1286
    .bdrv_snapshot_goto     = qcow2_snapshot_goto,
1287
    .bdrv_snapshot_delete   = qcow2_snapshot_delete,
1288
    .bdrv_snapshot_list     = qcow2_snapshot_list,
1289
    .bdrv_snapshot_load_tmp     = qcow2_snapshot_load_tmp,
1290
    .bdrv_get_info        = qcow_get_info,
1291

    
1292
    .bdrv_save_vmstate    = qcow_save_vmstate,
1293
    .bdrv_load_vmstate    = qcow_load_vmstate,
1294

    
1295
    .bdrv_change_backing_file   = qcow2_change_backing_file,
1296

    
1297
    .create_options = qcow_create_options,
1298
    .bdrv_check = qcow_check,
1299
};
1300

    
1301
static void bdrv_qcow2_init(void)
1302
{
1303
    bdrv_register(&bdrv_qcow2);
1304
}
1305

    
1306
block_init(bdrv_qcow2_init);