Statistics
| Branch: | Revision:

root / block / qcow2.c @ 9ccb258e

History | View | Annotate | Download (91.9 kB)

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

    
30
/*
31
  Differences with QCOW:
32

33
  - Support for multiple incremental snapshots.
34
  - Memory management by reference counts.
35
  - Clusters which have a reference count of one have the bit
36
    QCOW_OFLAG_COPIED to optimize write performance.
37
  - Size of compressed clusters is stored in sectors to reduce bit usage
38
    in the cluster offsets.
39
  - Support for storing additional data (such as the VM state) in the
40
    snapshots.
41
  - If a backing store is used, the cluster size is not constrained
42
    (could be backported to QCOW).
43
  - L2 tables have always a size of one cluster.
44
*/
45

    
46
//#define DEBUG_ALLOC
47
//#define DEBUG_ALLOC2
48
//#define DEBUG_EXT
49

    
50
#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
51
#define QCOW_VERSION 2
52

    
53
#define QCOW_CRYPT_NONE 0
54
#define QCOW_CRYPT_AES  1
55

    
56
#define QCOW_MAX_CRYPT_CLUSTERS 32
57

    
58
/* indicate that the refcount of the referenced cluster is exactly one. */
59
#define QCOW_OFLAG_COPIED     (1LL << 63)
60
/* indicate that the cluster is compressed (they never have the copied flag) */
61
#define QCOW_OFLAG_COMPRESSED (1LL << 62)
62

    
63
#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
64

    
65
#define MIN_CLUSTER_BITS 9
66
#define MAX_CLUSTER_BITS 16
67

    
68
typedef struct QCowHeader {
69
    uint32_t magic;
70
    uint32_t version;
71
    uint64_t backing_file_offset;
72
    uint32_t backing_file_size;
73
    uint32_t cluster_bits;
74
    uint64_t size; /* in bytes */
75
    uint32_t crypt_method;
76
    uint32_t l1_size; /* XXX: save number of clusters instead ? */
77
    uint64_t l1_table_offset;
78
    uint64_t refcount_table_offset;
79
    uint32_t refcount_table_clusters;
80
    uint32_t nb_snapshots;
81
    uint64_t snapshots_offset;
82
} QCowHeader;
83

    
84

    
85
typedef struct {
86
    uint32_t magic;
87
    uint32_t len;
88
} QCowExtension;
89
#define  QCOW_EXT_MAGIC_END 0
90
#define  QCOW_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
91

    
92

    
93
typedef struct __attribute__((packed)) QCowSnapshotHeader {
94
    /* header is 8 byte aligned */
95
    uint64_t l1_table_offset;
96

    
97
    uint32_t l1_size;
98
    uint16_t id_str_size;
99
    uint16_t name_size;
100

    
101
    uint32_t date_sec;
102
    uint32_t date_nsec;
103

    
104
    uint64_t vm_clock_nsec;
105

    
106
    uint32_t vm_state_size;
107
    uint32_t extra_data_size; /* for extension */
108
    /* extra data follows */
109
    /* id_str follows */
110
    /* name follows  */
111
} QCowSnapshotHeader;
112

    
113
#define L2_CACHE_SIZE 16
114

    
115
typedef struct QCowSnapshot {
116
    uint64_t l1_table_offset;
117
    uint32_t l1_size;
118
    char *id_str;
119
    char *name;
120
    uint32_t vm_state_size;
121
    uint32_t date_sec;
122
    uint32_t date_nsec;
123
    uint64_t vm_clock_nsec;
124
} QCowSnapshot;
125

    
126
typedef struct BDRVQcowState {
127
    BlockDriverState *hd;
128
    int cluster_bits;
129
    int cluster_size;
130
    int cluster_sectors;
131
    int l2_bits;
132
    int l2_size;
133
    int l1_size;
134
    int l1_vm_state_index;
135
    int csize_shift;
136
    int csize_mask;
137
    uint64_t cluster_offset_mask;
138
    uint64_t l1_table_offset;
139
    uint64_t *l1_table;
140
    uint64_t *l2_cache;
141
    uint64_t l2_cache_offsets[L2_CACHE_SIZE];
142
    uint32_t l2_cache_counts[L2_CACHE_SIZE];
143
    uint8_t *cluster_cache;
144
    uint8_t *cluster_data;
145
    uint64_t cluster_cache_offset;
146

    
147
    uint64_t *refcount_table;
148
    uint64_t refcount_table_offset;
149
    uint32_t refcount_table_size;
150
    uint64_t refcount_block_cache_offset;
151
    uint16_t *refcount_block_cache;
152
    int64_t free_cluster_index;
153
    int64_t free_byte_offset;
154

    
155
    uint32_t crypt_method; /* current crypt method, 0 if no key yet */
156
    uint32_t crypt_method_header;
157
    AES_KEY aes_encrypt_key;
158
    AES_KEY aes_decrypt_key;
159
    uint64_t snapshots_offset;
160
    int snapshots_size;
161
    int nb_snapshots;
162
    QCowSnapshot *snapshots;
163
} BDRVQcowState;
164

    
165
static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
166
static int qcow_read(BlockDriverState *bs, int64_t sector_num,
167
                     uint8_t *buf, int nb_sectors);
168
static int qcow_read_snapshots(BlockDriverState *bs);
169
static void qcow_free_snapshots(BlockDriverState *bs);
170
static int refcount_init(BlockDriverState *bs);
171
static void refcount_close(BlockDriverState *bs);
172
static int get_refcount(BlockDriverState *bs, int64_t cluster_index);
173
static int update_cluster_refcount(BlockDriverState *bs,
174
                                   int64_t cluster_index,
175
                                   int addend);
176
static int update_refcount(BlockDriverState *bs,
177
                            int64_t offset, int64_t length,
178
                            int addend);
179
static int64_t alloc_clusters(BlockDriverState *bs, int64_t size);
180
static int64_t alloc_bytes(BlockDriverState *bs, int size);
181
static void free_clusters(BlockDriverState *bs,
182
                          int64_t offset, int64_t size);
183
static int check_refcounts(BlockDriverState *bs);
184

    
185
static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
186
{
187
    const QCowHeader *cow_header = (const void *)buf;
188

    
189
    if (buf_size >= sizeof(QCowHeader) &&
190
        be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
191
        be32_to_cpu(cow_header->version) == QCOW_VERSION)
192
        return 100;
193
    else
194
        return 0;
195
}
196

    
197

    
198
/* 
199
 * read qcow2 extension and fill bs
200
 * start reading from start_offset
201
 * finish reading upon magic of value 0 or when end_offset reached
202
 * unknown magic is skipped (future extension this version knows nothing about)
203
 * return 0 upon success, non-0 otherwise
204
 */
205
static int qcow_read_extensions(BlockDriverState *bs, uint64_t start_offset,
206
                                uint64_t end_offset)
207
{
208
    BDRVQcowState *s = bs->opaque;
209
    QCowExtension ext;
210
    uint64_t offset;
211

    
212
#ifdef DEBUG_EXT
213
    printf("qcow_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
214
#endif
215
    offset = start_offset;
216
    while (offset < end_offset) {
217

    
218
#ifdef DEBUG_EXT
219
        /* Sanity check */
220
        if (offset > s->cluster_size)
221
            printf("qcow_handle_extension: suspicious offset %lu\n", offset);
222

    
223
        printf("attemting to read extended header in offset %lu\n", offset);
224
#endif
225

    
226
        if (bdrv_pread(s->hd, offset, &ext, sizeof(ext)) != sizeof(ext)) {
227
            fprintf(stderr, "qcow_handle_extension: ERROR: pread fail from offset %llu\n",
228
                    (unsigned long long)offset);
229
            return 1;
230
        }
231
        be32_to_cpus(&ext.magic);
232
        be32_to_cpus(&ext.len);
233
        offset += sizeof(ext);
234
#ifdef DEBUG_EXT
235
        printf("ext.magic = 0x%x\n", ext.magic);
236
#endif
237
        switch (ext.magic) {
238
        case QCOW_EXT_MAGIC_END:
239
            return 0;
240

    
241
        case QCOW_EXT_MAGIC_BACKING_FORMAT:
242
            if (ext.len >= sizeof(bs->backing_format)) {
243
                fprintf(stderr, "ERROR: ext_backing_format: len=%u too large"
244
                        " (>=%zu)\n",
245
                        ext.len, sizeof(bs->backing_format));
246
                return 2;
247
            }
248
            if (bdrv_pread(s->hd, offset , bs->backing_format,
249
                           ext.len) != ext.len)
250
                return 3;
251
            bs->backing_format[ext.len] = '\0';
252
#ifdef DEBUG_EXT
253
            printf("Qcow2: Got format extension %s\n", bs->backing_format);
254
#endif
255
            offset += ((ext.len + 7) & ~7);
256
            break;
257

    
258
        default:
259
            /* unknown magic -- just skip it */
260
            offset += ((ext.len + 7) & ~7);
261
            break;
262
        }
263
    }
264

    
265
    return 0;
266
}
267

    
268

    
269
static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
270
{
271
    BDRVQcowState *s = bs->opaque;
272
    int len, i, shift, ret;
273
    QCowHeader header;
274
    uint64_t ext_end;
275

    
276
    /* Performance is terrible right now with cache=writethrough due mainly
277
     * to reference count updates.  If the user does not explicitly specify
278
     * a caching type, force to writeback caching.
279
     */
280
    if ((flags & BDRV_O_CACHE_DEF)) {
281
        flags |= BDRV_O_CACHE_WB;
282
        flags &= ~BDRV_O_CACHE_DEF;
283
    }
284
    ret = bdrv_file_open(&s->hd, filename, flags);
285
    if (ret < 0)
286
        return ret;
287
    if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
288
        goto fail;
289
    be32_to_cpus(&header.magic);
290
    be32_to_cpus(&header.version);
291
    be64_to_cpus(&header.backing_file_offset);
292
    be32_to_cpus(&header.backing_file_size);
293
    be64_to_cpus(&header.size);
294
    be32_to_cpus(&header.cluster_bits);
295
    be32_to_cpus(&header.crypt_method);
296
    be64_to_cpus(&header.l1_table_offset);
297
    be32_to_cpus(&header.l1_size);
298
    be64_to_cpus(&header.refcount_table_offset);
299
    be32_to_cpus(&header.refcount_table_clusters);
300
    be64_to_cpus(&header.snapshots_offset);
301
    be32_to_cpus(&header.nb_snapshots);
302

    
303
    if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
304
        goto fail;
305
    if (header.size <= 1 ||
306
        header.cluster_bits < MIN_CLUSTER_BITS ||
307
        header.cluster_bits > MAX_CLUSTER_BITS)
308
        goto fail;
309
    if (header.crypt_method > QCOW_CRYPT_AES)
310
        goto fail;
311
    s->crypt_method_header = header.crypt_method;
312
    if (s->crypt_method_header)
313
        bs->encrypted = 1;
314
    s->cluster_bits = header.cluster_bits;
315
    s->cluster_size = 1 << s->cluster_bits;
316
    s->cluster_sectors = 1 << (s->cluster_bits - 9);
317
    s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
318
    s->l2_size = 1 << s->l2_bits;
319
    bs->total_sectors = header.size / 512;
320
    s->csize_shift = (62 - (s->cluster_bits - 8));
321
    s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
322
    s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
323
    s->refcount_table_offset = header.refcount_table_offset;
324
    s->refcount_table_size =
325
        header.refcount_table_clusters << (s->cluster_bits - 3);
326

    
327
    s->snapshots_offset = header.snapshots_offset;
328
    s->nb_snapshots = header.nb_snapshots;
329

    
330
    /* read the level 1 table */
331
    s->l1_size = header.l1_size;
332
    shift = s->cluster_bits + s->l2_bits;
333
    s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift;
334
    /* the L1 table must contain at least enough entries to put
335
       header.size bytes */
336
    if (s->l1_size < s->l1_vm_state_index)
337
        goto fail;
338
    s->l1_table_offset = header.l1_table_offset;
339
    s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
340
    if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
341
        s->l1_size * sizeof(uint64_t))
342
        goto fail;
343
    for(i = 0;i < s->l1_size; i++) {
344
        be64_to_cpus(&s->l1_table[i]);
345
    }
346
    /* alloc L2 cache */
347
    s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
348
    s->cluster_cache = qemu_malloc(s->cluster_size);
349
    /* one more sector for decompressed data alignment */
350
    s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
351
                                  + 512);
352
    s->cluster_cache_offset = -1;
353

    
354
    if (refcount_init(bs) < 0)
355
        goto fail;
356

    
357
    /* read qcow2 extensions */
358
    if (header.backing_file_offset)
359
        ext_end = header.backing_file_offset;
360
    else
361
        ext_end = s->cluster_size;
362
    if (qcow_read_extensions(bs, sizeof(header), ext_end))
363
        goto fail;
364

    
365
    /* read the backing file name */
366
    if (header.backing_file_offset != 0) {
367
        len = header.backing_file_size;
368
        if (len > 1023)
369
            len = 1023;
370
        if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
371
            goto fail;
372
        bs->backing_file[len] = '\0';
373
    }
374
    if (qcow_read_snapshots(bs) < 0)
375
        goto fail;
376

    
377
#ifdef DEBUG_ALLOC
378
    check_refcounts(bs);
379
#endif
380
    return 0;
381

    
382
 fail:
383
    qcow_free_snapshots(bs);
384
    refcount_close(bs);
385
    qemu_free(s->l1_table);
386
    qemu_free(s->l2_cache);
387
    qemu_free(s->cluster_cache);
388
    qemu_free(s->cluster_data);
389
    bdrv_delete(s->hd);
390
    return -1;
391
}
392

    
393
static int qcow_set_key(BlockDriverState *bs, const char *key)
394
{
395
    BDRVQcowState *s = bs->opaque;
396
    uint8_t keybuf[16];
397
    int len, i;
398

    
399
    memset(keybuf, 0, 16);
400
    len = strlen(key);
401
    if (len > 16)
402
        len = 16;
403
    /* XXX: we could compress the chars to 7 bits to increase
404
       entropy */
405
    for(i = 0;i < len;i++) {
406
        keybuf[i] = key[i];
407
    }
408
    s->crypt_method = s->crypt_method_header;
409

    
410
    if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
411
        return -1;
412
    if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
413
        return -1;
414
#if 0
415
    /* test */
416
    {
417
        uint8_t in[16];
418
        uint8_t out[16];
419
        uint8_t tmp[16];
420
        for(i=0;i<16;i++)
421
            in[i] = i;
422
        AES_encrypt(in, tmp, &s->aes_encrypt_key);
423
        AES_decrypt(tmp, out, &s->aes_decrypt_key);
424
        for(i = 0; i < 16; i++)
425
            printf(" %02x", tmp[i]);
426
        printf("\n");
427
        for(i = 0; i < 16; i++)
428
            printf(" %02x", out[i]);
429
        printf("\n");
430
    }
431
#endif
432
    return 0;
433
}
434

    
435
/* The crypt function is compatible with the linux cryptoloop
436
   algorithm for < 4 GB images. NOTE: out_buf == in_buf is
437
   supported */
438
static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
439
                            uint8_t *out_buf, const uint8_t *in_buf,
440
                            int nb_sectors, int enc,
441
                            const AES_KEY *key)
442
{
443
    union {
444
        uint64_t ll[2];
445
        uint8_t b[16];
446
    } ivec;
447
    int i;
448

    
449
    for(i = 0; i < nb_sectors; i++) {
450
        ivec.ll[0] = cpu_to_le64(sector_num);
451
        ivec.ll[1] = 0;
452
        AES_cbc_encrypt(in_buf, out_buf, 512, key,
453
                        ivec.b, enc);
454
        sector_num++;
455
        in_buf += 512;
456
        out_buf += 512;
457
    }
458
}
459

    
460
static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
461
                        uint64_t cluster_offset, int n_start, int n_end)
462
{
463
    BDRVQcowState *s = bs->opaque;
464
    int n, ret;
465

    
466
    n = n_end - n_start;
467
    if (n <= 0)
468
        return 0;
469
    ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
470
    if (ret < 0)
471
        return ret;
472
    if (s->crypt_method) {
473
        encrypt_sectors(s, start_sect + n_start,
474
                        s->cluster_data,
475
                        s->cluster_data, n, 1,
476
                        &s->aes_encrypt_key);
477
    }
478
    ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
479
                     s->cluster_data, n);
480
    if (ret < 0)
481
        return ret;
482
    return 0;
483
}
484

    
485
static void l2_cache_reset(BlockDriverState *bs)
486
{
487
    BDRVQcowState *s = bs->opaque;
488

    
489
    memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
490
    memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
491
    memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
492
}
493

    
494
static inline int l2_cache_new_entry(BlockDriverState *bs)
495
{
496
    BDRVQcowState *s = bs->opaque;
497
    uint32_t min_count;
498
    int min_index, i;
499

    
500
    /* find a new entry in the least used one */
501
    min_index = 0;
502
    min_count = 0xffffffff;
503
    for(i = 0; i < L2_CACHE_SIZE; i++) {
504
        if (s->l2_cache_counts[i] < min_count) {
505
            min_count = s->l2_cache_counts[i];
506
            min_index = i;
507
        }
508
    }
509
    return min_index;
510
}
511

    
512
static int64_t align_offset(int64_t offset, int n)
513
{
514
    offset = (offset + n - 1) & ~(n - 1);
515
    return offset;
516
}
517

    
518
static int grow_l1_table(BlockDriverState *bs, int min_size)
519
{
520
    BDRVQcowState *s = bs->opaque;
521
    int new_l1_size, new_l1_size2, ret, i;
522
    uint64_t *new_l1_table;
523
    uint64_t new_l1_table_offset;
524
    uint8_t data[12];
525

    
526
    new_l1_size = s->l1_size;
527
    if (min_size <= new_l1_size)
528
        return 0;
529
    while (min_size > new_l1_size) {
530
        new_l1_size = (new_l1_size * 3 + 1) / 2;
531
    }
532
#ifdef DEBUG_ALLOC2
533
    printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
534
#endif
535

    
536
    new_l1_size2 = sizeof(uint64_t) * new_l1_size;
537
    new_l1_table = qemu_mallocz(new_l1_size2);
538
    memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
539

    
540
    /* write new table (align to cluster) */
541
    new_l1_table_offset = alloc_clusters(bs, new_l1_size2);
542

    
543
    for(i = 0; i < s->l1_size; i++)
544
        new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
545
    ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
546
    if (ret != new_l1_size2)
547
        goto fail;
548
    for(i = 0; i < s->l1_size; i++)
549
        new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
550

    
551
    /* set new table */
552
    cpu_to_be32w((uint32_t*)data, new_l1_size);
553
    cpu_to_be64w((uint64_t*)(data + 4), new_l1_table_offset);
554
    if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size), data,
555
                sizeof(data)) != sizeof(data))
556
        goto fail;
557
    qemu_free(s->l1_table);
558
    free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
559
    s->l1_table_offset = new_l1_table_offset;
560
    s->l1_table = new_l1_table;
561
    s->l1_size = new_l1_size;
562
    return 0;
563
 fail:
564
    qemu_free(s->l1_table);
565
    return -EIO;
566
}
567

    
568
/*
569
 * seek_l2_table
570
 *
571
 * seek l2_offset in the l2_cache table
572
 * if not found, return NULL,
573
 * if found,
574
 *   increments the l2 cache hit count of the entry,
575
 *   if counter overflow, divide by two all counters
576
 *   return the pointer to the l2 cache entry
577
 *
578
 */
579

    
580
static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset)
581
{
582
    int i, j;
583

    
584
    for(i = 0; i < L2_CACHE_SIZE; i++) {
585
        if (l2_offset == s->l2_cache_offsets[i]) {
586
            /* increment the hit count */
587
            if (++s->l2_cache_counts[i] == 0xffffffff) {
588
                for(j = 0; j < L2_CACHE_SIZE; j++) {
589
                    s->l2_cache_counts[j] >>= 1;
590
                }
591
            }
592
            return s->l2_cache + (i << s->l2_bits);
593
        }
594
    }
595
    return NULL;
596
}
597

    
598
/*
599
 * l2_load
600
 *
601
 * Loads a L2 table into memory. If the table is in the cache, the cache
602
 * is used; otherwise the L2 table is loaded from the image file.
603
 *
604
 * Returns a pointer to the L2 table on success, or NULL if the read from
605
 * the image file failed.
606
 */
607

    
608
static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset)
609
{
610
    BDRVQcowState *s = bs->opaque;
611
    int min_index;
612
    uint64_t *l2_table;
613

    
614
    /* seek if the table for the given offset is in the cache */
615

    
616
    l2_table = seek_l2_table(s, l2_offset);
617
    if (l2_table != NULL)
618
        return l2_table;
619

    
620
    /* not found: load a new entry in the least used one */
621

    
622
    min_index = l2_cache_new_entry(bs);
623
    l2_table = s->l2_cache + (min_index << s->l2_bits);
624
    if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
625
        s->l2_size * sizeof(uint64_t))
626
        return NULL;
627
    s->l2_cache_offsets[min_index] = l2_offset;
628
    s->l2_cache_counts[min_index] = 1;
629

    
630
    return l2_table;
631
}
632

    
633
/*
634
 * l2_allocate
635
 *
636
 * Allocate a new l2 entry in the file. If l1_index points to an already
637
 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
638
 * table) copy the contents of the old L2 table into the newly allocated one.
639
 * Otherwise the new table is initialized with zeros.
640
 *
641
 */
642

    
643
static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
644
{
645
    BDRVQcowState *s = bs->opaque;
646
    int min_index;
647
    uint64_t old_l2_offset, tmp;
648
    uint64_t *l2_table, l2_offset;
649

    
650
    old_l2_offset = s->l1_table[l1_index];
651

    
652
    /* allocate a new l2 entry */
653

    
654
    l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
655

    
656
    /* update the L1 entry */
657

    
658
    s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
659

    
660
    tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED);
661
    if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
662
                    &tmp, sizeof(tmp)) != sizeof(tmp))
663
        return NULL;
664

    
665
    /* allocate a new entry in the l2 cache */
666

    
667
    min_index = l2_cache_new_entry(bs);
668
    l2_table = s->l2_cache + (min_index << s->l2_bits);
669

    
670
    if (old_l2_offset == 0) {
671
        /* if there was no old l2 table, clear the new table */
672
        memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
673
    } else {
674
        /* if there was an old l2 table, read it from the disk */
675
        if (bdrv_pread(s->hd, old_l2_offset,
676
                       l2_table, s->l2_size * sizeof(uint64_t)) !=
677
            s->l2_size * sizeof(uint64_t))
678
            return NULL;
679
    }
680
    /* write the l2 table to the file */
681
    if (bdrv_pwrite(s->hd, l2_offset,
682
                    l2_table, s->l2_size * sizeof(uint64_t)) !=
683
        s->l2_size * sizeof(uint64_t))
684
        return NULL;
685

    
686
    /* update the l2 cache entry */
687

    
688
    s->l2_cache_offsets[min_index] = l2_offset;
689
    s->l2_cache_counts[min_index] = 1;
690

    
691
    return l2_table;
692
}
693

    
694
static int size_to_clusters(BDRVQcowState *s, int64_t size)
695
{
696
    return (size + (s->cluster_size - 1)) >> s->cluster_bits;
697
}
698

    
699
static int count_contiguous_clusters(uint64_t nb_clusters, int cluster_size,
700
        uint64_t *l2_table, uint64_t start, uint64_t mask)
701
{
702
    int i;
703
    uint64_t offset = be64_to_cpu(l2_table[0]) & ~mask;
704

    
705
    if (!offset)
706
        return 0;
707

    
708
    for (i = start; i < start + nb_clusters; i++)
709
        if (offset + i * cluster_size != (be64_to_cpu(l2_table[i]) & ~mask))
710
            break;
711

    
712
        return (i - start);
713
}
714

    
715
static int count_contiguous_free_clusters(uint64_t nb_clusters, uint64_t *l2_table)
716
{
717
    int i = 0;
718

    
719
    while(nb_clusters-- && l2_table[i] == 0)
720
        i++;
721

    
722
    return i;
723
}
724

    
725
/*
726
 * get_cluster_offset
727
 *
728
 * For a given offset of the disk image, return cluster offset in
729
 * qcow2 file.
730
 *
731
 * on entry, *num is the number of contiguous clusters we'd like to
732
 * access following offset.
733
 *
734
 * on exit, *num is the number of contiguous clusters we can read.
735
 *
736
 * Return 1, if the offset is found
737
 * Return 0, otherwise.
738
 *
739
 */
740

    
741
static uint64_t get_cluster_offset(BlockDriverState *bs,
742
                                   uint64_t offset, int *num)
743
{
744
    BDRVQcowState *s = bs->opaque;
745
    int l1_index, l2_index;
746
    uint64_t l2_offset, *l2_table, cluster_offset;
747
    int l1_bits, c;
748
    int index_in_cluster, nb_available, nb_needed, nb_clusters;
749

    
750
    index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
751
    nb_needed = *num + index_in_cluster;
752

    
753
    l1_bits = s->l2_bits + s->cluster_bits;
754

    
755
    /* compute how many bytes there are between the offset and
756
     * the end of the l1 entry
757
     */
758

    
759
    nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1));
760

    
761
    /* compute the number of available sectors */
762

    
763
    nb_available = (nb_available >> 9) + index_in_cluster;
764

    
765
    if (nb_needed > nb_available) {
766
        nb_needed = nb_available;
767
    }
768

    
769
    cluster_offset = 0;
770

    
771
    /* seek the the l2 offset in the l1 table */
772

    
773
    l1_index = offset >> l1_bits;
774
    if (l1_index >= s->l1_size)
775
        goto out;
776

    
777
    l2_offset = s->l1_table[l1_index];
778

    
779
    /* seek the l2 table of the given l2 offset */
780

    
781
    if (!l2_offset)
782
        goto out;
783

    
784
    /* load the l2 table in memory */
785

    
786
    l2_offset &= ~QCOW_OFLAG_COPIED;
787
    l2_table = l2_load(bs, l2_offset);
788
    if (l2_table == NULL)
789
        return 0;
790

    
791
    /* find the cluster offset for the given disk offset */
792

    
793
    l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
794
    cluster_offset = be64_to_cpu(l2_table[l2_index]);
795
    nb_clusters = size_to_clusters(s, nb_needed << 9);
796

    
797
    if (!cluster_offset) {
798
        /* how many empty clusters ? */
799
        c = count_contiguous_free_clusters(nb_clusters, &l2_table[l2_index]);
800
    } else {
801
        /* how many allocated clusters ? */
802
        c = count_contiguous_clusters(nb_clusters, s->cluster_size,
803
                &l2_table[l2_index], 0, QCOW_OFLAG_COPIED);
804
    }
805

    
806
   nb_available = (c * s->cluster_sectors);
807
out:
808
    if (nb_available > nb_needed)
809
        nb_available = nb_needed;
810

    
811
    *num = nb_available - index_in_cluster;
812

    
813
    return cluster_offset & ~QCOW_OFLAG_COPIED;
814
}
815

    
816
/*
817
 * free_any_clusters
818
 *
819
 * free clusters according to its type: compressed or not
820
 *
821
 */
822

    
823
static void free_any_clusters(BlockDriverState *bs,
824
                              uint64_t cluster_offset, int nb_clusters)
825
{
826
    BDRVQcowState *s = bs->opaque;
827

    
828
    /* free the cluster */
829

    
830
    if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
831
        int nb_csectors;
832
        nb_csectors = ((cluster_offset >> s->csize_shift) &
833
                       s->csize_mask) + 1;
834
        free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
835
                      nb_csectors * 512);
836
        return;
837
    }
838

    
839
    free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
840

    
841
    return;
842
}
843

    
844
/*
845
 * get_cluster_table
846
 *
847
 * for a given disk offset, load (and allocate if needed)
848
 * the l2 table.
849
 *
850
 * the l2 table offset in the qcow2 file and the cluster index
851
 * in the l2 table are given to the caller.
852
 *
853
 */
854

    
855
static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
856
                             uint64_t **new_l2_table,
857
                             uint64_t *new_l2_offset,
858
                             int *new_l2_index)
859
{
860
    BDRVQcowState *s = bs->opaque;
861
    int l1_index, l2_index, ret;
862
    uint64_t l2_offset, *l2_table;
863

    
864
    /* seek the the l2 offset in the l1 table */
865

    
866
    l1_index = offset >> (s->l2_bits + s->cluster_bits);
867
    if (l1_index >= s->l1_size) {
868
        ret = grow_l1_table(bs, l1_index + 1);
869
        if (ret < 0)
870
            return 0;
871
    }
872
    l2_offset = s->l1_table[l1_index];
873

    
874
    /* seek the l2 table of the given l2 offset */
875

    
876
    if (l2_offset & QCOW_OFLAG_COPIED) {
877
        /* load the l2 table in memory */
878
        l2_offset &= ~QCOW_OFLAG_COPIED;
879
        l2_table = l2_load(bs, l2_offset);
880
        if (l2_table == NULL)
881
            return 0;
882
    } else {
883
        if (l2_offset)
884
            free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
885
        l2_table = l2_allocate(bs, l1_index);
886
        if (l2_table == NULL)
887
            return 0;
888
        l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
889
    }
890

    
891
    /* find the cluster offset for the given disk offset */
892

    
893
    l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
894

    
895
    *new_l2_table = l2_table;
896
    *new_l2_offset = l2_offset;
897
    *new_l2_index = l2_index;
898

    
899
    return 1;
900
}
901

    
902
/*
903
 * alloc_compressed_cluster_offset
904
 *
905
 * For a given offset of the disk image, return cluster offset in
906
 * qcow2 file.
907
 *
908
 * If the offset is not found, allocate a new compressed cluster.
909
 *
910
 * Return the cluster offset if successful,
911
 * Return 0, otherwise.
912
 *
913
 */
914

    
915
static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
916
                                                uint64_t offset,
917
                                                int compressed_size)
918
{
919
    BDRVQcowState *s = bs->opaque;
920
    int l2_index, ret;
921
    uint64_t l2_offset, *l2_table, cluster_offset;
922
    int nb_csectors;
923

    
924
    ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
925
    if (ret == 0)
926
        return 0;
927

    
928
    cluster_offset = be64_to_cpu(l2_table[l2_index]);
929
    if (cluster_offset & QCOW_OFLAG_COPIED)
930
        return cluster_offset & ~QCOW_OFLAG_COPIED;
931

    
932
    if (cluster_offset)
933
        free_any_clusters(bs, cluster_offset, 1);
934

    
935
    cluster_offset = alloc_bytes(bs, compressed_size);
936
    nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
937
                  (cluster_offset >> 9);
938

    
939
    cluster_offset |= QCOW_OFLAG_COMPRESSED |
940
                      ((uint64_t)nb_csectors << s->csize_shift);
941

    
942
    /* update L2 table */
943

    
944
    /* compressed clusters never have the copied flag */
945

    
946
    l2_table[l2_index] = cpu_to_be64(cluster_offset);
947
    if (bdrv_pwrite(s->hd,
948
                    l2_offset + l2_index * sizeof(uint64_t),
949
                    l2_table + l2_index,
950
                    sizeof(uint64_t)) != sizeof(uint64_t))
951
        return 0;
952

    
953
    return cluster_offset;
954
}
955

    
956
typedef struct QCowL2Meta
957
{
958
    uint64_t offset;
959
    int n_start;
960
    int nb_available;
961
    int nb_clusters;
962
} QCowL2Meta;
963

    
964
static int alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset,
965
        QCowL2Meta *m)
966
{
967
    BDRVQcowState *s = bs->opaque;
968
    int i, j = 0, l2_index, ret;
969
    uint64_t *old_cluster, start_sect, l2_offset, *l2_table;
970

    
971
    if (m->nb_clusters == 0)
972
        return 0;
973

    
974
    old_cluster = qemu_malloc(m->nb_clusters * sizeof(uint64_t));
975

    
976
    /* copy content of unmodified sectors */
977
    start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
978
    if (m->n_start) {
979
        ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
980
        if (ret < 0)
981
            goto err;
982
    }
983

    
984
    if (m->nb_available & (s->cluster_sectors - 1)) {
985
        uint64_t end = m->nb_available & ~(uint64_t)(s->cluster_sectors - 1);
986
        ret = copy_sectors(bs, start_sect + end, cluster_offset + (end << 9),
987
                m->nb_available - end, s->cluster_sectors);
988
        if (ret < 0)
989
            goto err;
990
    }
991

    
992
    ret = -EIO;
993
    /* update L2 table */
994
    if (!get_cluster_table(bs, m->offset, &l2_table, &l2_offset, &l2_index))
995
        goto err;
996

    
997
    for (i = 0; i < m->nb_clusters; i++) {
998
        /* if two concurrent writes happen to the same unallocated cluster
999
         * each write allocates separate cluster and writes data concurrently.
1000
         * The first one to complete updates l2 table with pointer to its
1001
         * cluster the second one has to do RMW (which is done above by
1002
         * copy_sectors()), update l2 table with its cluster pointer and free
1003
         * old cluster. This is what this loop does */
1004
        if(l2_table[l2_index + i] != 0)
1005
            old_cluster[j++] = l2_table[l2_index + i];
1006

    
1007
        l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
1008
                    (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
1009
     }
1010

    
1011
    if (bdrv_pwrite(s->hd, l2_offset + l2_index * sizeof(uint64_t),
1012
                l2_table + l2_index, m->nb_clusters * sizeof(uint64_t)) !=
1013
            m->nb_clusters * sizeof(uint64_t))
1014
        goto err;
1015

    
1016
    for (i = 0; i < j; i++)
1017
        free_any_clusters(bs, be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED,
1018
                          1);
1019

    
1020
    ret = 0;
1021
err:
1022
    qemu_free(old_cluster);
1023
    return ret;
1024
 }
1025

    
1026
/*
1027
 * alloc_cluster_offset
1028
 *
1029
 * For a given offset of the disk image, return cluster offset in
1030
 * qcow2 file.
1031
 *
1032
 * If the offset is not found, allocate a new cluster.
1033
 *
1034
 * Return the cluster offset if successful,
1035
 * Return 0, otherwise.
1036
 *
1037
 */
1038

    
1039
static uint64_t alloc_cluster_offset(BlockDriverState *bs,
1040
                                     uint64_t offset,
1041
                                     int n_start, int n_end,
1042
                                     int *num, QCowL2Meta *m)
1043
{
1044
    BDRVQcowState *s = bs->opaque;
1045
    int l2_index, ret;
1046
    uint64_t l2_offset, *l2_table, cluster_offset;
1047
    int nb_clusters, i = 0;
1048

    
1049
    ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
1050
    if (ret == 0)
1051
        return 0;
1052

    
1053
    nb_clusters = size_to_clusters(s, n_end << 9);
1054

    
1055
    nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
1056

    
1057
    cluster_offset = be64_to_cpu(l2_table[l2_index]);
1058

    
1059
    /* We keep all QCOW_OFLAG_COPIED clusters */
1060

    
1061
    if (cluster_offset & QCOW_OFLAG_COPIED) {
1062
        nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size,
1063
                &l2_table[l2_index], 0, 0);
1064

    
1065
        cluster_offset &= ~QCOW_OFLAG_COPIED;
1066
        m->nb_clusters = 0;
1067

    
1068
        goto out;
1069
    }
1070

    
1071
    /* for the moment, multiple compressed clusters are not managed */
1072

    
1073
    if (cluster_offset & QCOW_OFLAG_COMPRESSED)
1074
        nb_clusters = 1;
1075

    
1076
    /* how many available clusters ? */
1077

    
1078
    while (i < nb_clusters) {
1079
        i += count_contiguous_clusters(nb_clusters - i, s->cluster_size,
1080
                &l2_table[l2_index], i, 0);
1081

    
1082
        if(be64_to_cpu(l2_table[l2_index + i]))
1083
            break;
1084

    
1085
        i += count_contiguous_free_clusters(nb_clusters - i,
1086
                &l2_table[l2_index + i]);
1087

    
1088
        cluster_offset = be64_to_cpu(l2_table[l2_index + i]);
1089

    
1090
        if ((cluster_offset & QCOW_OFLAG_COPIED) ||
1091
                (cluster_offset & QCOW_OFLAG_COMPRESSED))
1092
            break;
1093
    }
1094
    nb_clusters = i;
1095

    
1096
    /* allocate a new cluster */
1097

    
1098
    cluster_offset = alloc_clusters(bs, nb_clusters * s->cluster_size);
1099

    
1100
    /* save info needed for meta data update */
1101
    m->offset = offset;
1102
    m->n_start = n_start;
1103
    m->nb_clusters = nb_clusters;
1104

    
1105
out:
1106
    m->nb_available = MIN(nb_clusters << (s->cluster_bits - 9), n_end);
1107

    
1108
    *num = m->nb_available - n_start;
1109

    
1110
    return cluster_offset;
1111
}
1112

    
1113
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
1114
                             int nb_sectors, int *pnum)
1115
{
1116
    uint64_t cluster_offset;
1117

    
1118
    *pnum = nb_sectors;
1119
    cluster_offset = get_cluster_offset(bs, sector_num << 9, pnum);
1120

    
1121
    return (cluster_offset != 0);
1122
}
1123

    
1124
static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
1125
                             const uint8_t *buf, int buf_size)
1126
{
1127
    z_stream strm1, *strm = &strm1;
1128
    int ret, out_len;
1129

    
1130
    memset(strm, 0, sizeof(*strm));
1131

    
1132
    strm->next_in = (uint8_t *)buf;
1133
    strm->avail_in = buf_size;
1134
    strm->next_out = out_buf;
1135
    strm->avail_out = out_buf_size;
1136

    
1137
    ret = inflateInit2(strm, -12);
1138
    if (ret != Z_OK)
1139
        return -1;
1140
    ret = inflate(strm, Z_FINISH);
1141
    out_len = strm->next_out - out_buf;
1142
    if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
1143
        out_len != out_buf_size) {
1144
        inflateEnd(strm);
1145
        return -1;
1146
    }
1147
    inflateEnd(strm);
1148
    return 0;
1149
}
1150

    
1151
static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
1152
{
1153
    int ret, csize, nb_csectors, sector_offset;
1154
    uint64_t coffset;
1155

    
1156
    coffset = cluster_offset & s->cluster_offset_mask;
1157
    if (s->cluster_cache_offset != coffset) {
1158
        nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
1159
        sector_offset = coffset & 511;
1160
        csize = nb_csectors * 512 - sector_offset;
1161
        ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors);
1162
        if (ret < 0) {
1163
            return -1;
1164
        }
1165
        if (decompress_buffer(s->cluster_cache, s->cluster_size,
1166
                              s->cluster_data + sector_offset, csize) < 0) {
1167
            return -1;
1168
        }
1169
        s->cluster_cache_offset = coffset;
1170
    }
1171
    return 0;
1172
}
1173

    
1174
/* handle reading after the end of the backing file */
1175
static int backing_read1(BlockDriverState *bs,
1176
                         int64_t sector_num, uint8_t *buf, int nb_sectors)
1177
{
1178
    int n1;
1179
    if ((sector_num + nb_sectors) <= bs->total_sectors)
1180
        return nb_sectors;
1181
    if (sector_num >= bs->total_sectors)
1182
        n1 = 0;
1183
    else
1184
        n1 = bs->total_sectors - sector_num;
1185
    memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1));
1186
    return n1;
1187
}
1188

    
1189
static int qcow_read(BlockDriverState *bs, int64_t sector_num,
1190
                     uint8_t *buf, int nb_sectors)
1191
{
1192
    BDRVQcowState *s = bs->opaque;
1193
    int ret, index_in_cluster, n, n1;
1194
    uint64_t cluster_offset;
1195

    
1196
    while (nb_sectors > 0) {
1197
        n = nb_sectors;
1198
        cluster_offset = get_cluster_offset(bs, sector_num << 9, &n);
1199
        index_in_cluster = sector_num & (s->cluster_sectors - 1);
1200
        if (!cluster_offset) {
1201
            if (bs->backing_hd) {
1202
                /* read from the base image */
1203
                n1 = backing_read1(bs->backing_hd, sector_num, buf, n);
1204
                if (n1 > 0) {
1205
                    ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
1206
                    if (ret < 0)
1207
                        return -1;
1208
                }
1209
            } else {
1210
                memset(buf, 0, 512 * n);
1211
            }
1212
        } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
1213
            if (decompress_cluster(s, cluster_offset) < 0)
1214
                return -1;
1215
            memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
1216
        } else {
1217
            ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
1218
            if (ret != n * 512)
1219
                return -1;
1220
            if (s->crypt_method) {
1221
                encrypt_sectors(s, sector_num, buf, buf, n, 0,
1222
                                &s->aes_decrypt_key);
1223
            }
1224
        }
1225
        nb_sectors -= n;
1226
        sector_num += n;
1227
        buf += n * 512;
1228
    }
1229
    return 0;
1230
}
1231

    
1232
typedef struct QCowAIOCB {
1233
    BlockDriverAIOCB common;
1234
    int64_t sector_num;
1235
    QEMUIOVector *qiov;
1236
    uint8_t *buf;
1237
    void *orig_buf;
1238
    int nb_sectors;
1239
    int n;
1240
    uint64_t cluster_offset;
1241
    uint8_t *cluster_data;
1242
    BlockDriverAIOCB *hd_aiocb;
1243
    struct iovec hd_iov;
1244
    QEMUIOVector hd_qiov;
1245
    QEMUBH *bh;
1246
    QCowL2Meta l2meta;
1247
} QCowAIOCB;
1248

    
1249
static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
1250
{
1251
    QCowAIOCB *acb = (QCowAIOCB *)blockacb;
1252
    if (acb->hd_aiocb)
1253
        bdrv_aio_cancel(acb->hd_aiocb);
1254
    qemu_aio_release(acb);
1255
}
1256

    
1257
static AIOPool qcow_aio_pool = {
1258
    .aiocb_size         = sizeof(QCowAIOCB),
1259
    .cancel             = qcow_aio_cancel,
1260
};
1261

    
1262
static void qcow_aio_read_cb(void *opaque, int ret);
1263
static void qcow_aio_read_bh(void *opaque)
1264
{
1265
    QCowAIOCB *acb = opaque;
1266
    qemu_bh_delete(acb->bh);
1267
    acb->bh = NULL;
1268
    qcow_aio_read_cb(opaque, 0);
1269
}
1270

    
1271
static int qcow_schedule_bh(QEMUBHFunc *cb, QCowAIOCB *acb)
1272
{
1273
    if (acb->bh)
1274
        return -EIO;
1275

    
1276
    acb->bh = qemu_bh_new(cb, acb);
1277
    if (!acb->bh)
1278
        return -EIO;
1279

    
1280
    qemu_bh_schedule(acb->bh);
1281

    
1282
    return 0;
1283
}
1284

    
1285
static void qcow_aio_read_cb(void *opaque, int ret)
1286
{
1287
    QCowAIOCB *acb = opaque;
1288
    BlockDriverState *bs = acb->common.bs;
1289
    BDRVQcowState *s = bs->opaque;
1290
    int index_in_cluster, n1;
1291

    
1292
    acb->hd_aiocb = NULL;
1293
    if (ret < 0)
1294
        goto done;
1295

    
1296
    /* post process the read buffer */
1297
    if (!acb->cluster_offset) {
1298
        /* nothing to do */
1299
    } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
1300
        /* nothing to do */
1301
    } else {
1302
        if (s->crypt_method) {
1303
            encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
1304
                            acb->n, 0,
1305
                            &s->aes_decrypt_key);
1306
        }
1307
    }
1308

    
1309
    acb->nb_sectors -= acb->n;
1310
    acb->sector_num += acb->n;
1311
    acb->buf += acb->n * 512;
1312

    
1313
    if (acb->nb_sectors == 0) {
1314
        /* request completed */
1315
        ret = 0;
1316
        goto done;
1317
    }
1318

    
1319
    /* prepare next AIO request */
1320
    acb->n = acb->nb_sectors;
1321
    acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
1322
    index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
1323

    
1324
    if (!acb->cluster_offset) {
1325
        if (bs->backing_hd) {
1326
            /* read from the base image */
1327
            n1 = backing_read1(bs->backing_hd, acb->sector_num,
1328
                               acb->buf, acb->n);
1329
            if (n1 > 0) {
1330
                acb->hd_iov.iov_base = (void *)acb->buf;
1331
                acb->hd_iov.iov_len = acb->n * 512;
1332
                qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
1333
                acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num,
1334
                                    &acb->hd_qiov, acb->n,
1335
                                    qcow_aio_read_cb, acb);
1336
                if (acb->hd_aiocb == NULL)
1337
                    goto done;
1338
            } else {
1339
                ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
1340
                if (ret < 0)
1341
                    goto done;
1342
            }
1343
        } else {
1344
            /* Note: in this case, no need to wait */
1345
            memset(acb->buf, 0, 512 * acb->n);
1346
            ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
1347
            if (ret < 0)
1348
                goto done;
1349
        }
1350
    } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
1351
        /* add AIO support for compressed blocks ? */
1352
        if (decompress_cluster(s, acb->cluster_offset) < 0)
1353
            goto done;
1354
        memcpy(acb->buf,
1355
               s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
1356
        ret = qcow_schedule_bh(qcow_aio_read_bh, acb);
1357
        if (ret < 0)
1358
            goto done;
1359
    } else {
1360
        if ((acb->cluster_offset & 511) != 0) {
1361
            ret = -EIO;
1362
            goto done;
1363
        }
1364

    
1365
        acb->hd_iov.iov_base = (void *)acb->buf;
1366
        acb->hd_iov.iov_len = acb->n * 512;
1367
        qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
1368
        acb->hd_aiocb = bdrv_aio_readv(s->hd,
1369
                            (acb->cluster_offset >> 9) + index_in_cluster,
1370
                            &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb);
1371
        if (acb->hd_aiocb == NULL)
1372
            goto done;
1373
    }
1374

    
1375
    return;
1376
done:
1377
    if (acb->qiov->niov > 1) {
1378
        qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size);
1379
        qemu_vfree(acb->orig_buf);
1380
    }
1381
    acb->common.cb(acb->common.opaque, ret);
1382
    qemu_aio_release(acb);
1383
}
1384

    
1385
static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
1386
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
1387
        BlockDriverCompletionFunc *cb, void *opaque, int is_write)
1388
{
1389
    QCowAIOCB *acb;
1390

    
1391
    acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
1392
    if (!acb)
1393
        return NULL;
1394
    acb->hd_aiocb = NULL;
1395
    acb->sector_num = sector_num;
1396
    acb->qiov = qiov;
1397
    if (qiov->niov > 1) {
1398
        acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
1399
        if (is_write)
1400
            qemu_iovec_to_buffer(qiov, acb->buf);
1401
    } else {
1402
        acb->buf = (uint8_t *)qiov->iov->iov_base;
1403
    }
1404
    acb->nb_sectors = nb_sectors;
1405
    acb->n = 0;
1406
    acb->cluster_offset = 0;
1407
    acb->l2meta.nb_clusters = 0;
1408
    return acb;
1409
}
1410

    
1411
static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs,
1412
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
1413
        BlockDriverCompletionFunc *cb, void *opaque)
1414
{
1415
    QCowAIOCB *acb;
1416

    
1417
    acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
1418
    if (!acb)
1419
        return NULL;
1420

    
1421
    qcow_aio_read_cb(acb, 0);
1422
    return &acb->common;
1423
}
1424

    
1425
static void qcow_aio_write_cb(void *opaque, int ret)
1426
{
1427
    QCowAIOCB *acb = opaque;
1428
    BlockDriverState *bs = acb->common.bs;
1429
    BDRVQcowState *s = bs->opaque;
1430
    int index_in_cluster;
1431
    const uint8_t *src_buf;
1432
    int n_end;
1433

    
1434
    acb->hd_aiocb = NULL;
1435

    
1436
    if (ret < 0)
1437
        goto done;
1438

    
1439
    if (alloc_cluster_link_l2(bs, acb->cluster_offset, &acb->l2meta) < 0) {
1440
        free_any_clusters(bs, acb->cluster_offset, acb->l2meta.nb_clusters);
1441
        goto done;
1442
    }
1443

    
1444
    acb->nb_sectors -= acb->n;
1445
    acb->sector_num += acb->n;
1446
    acb->buf += acb->n * 512;
1447

    
1448
    if (acb->nb_sectors == 0) {
1449
        /* request completed */
1450
        ret = 0;
1451
        goto done;
1452
    }
1453

    
1454
    index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
1455
    n_end = index_in_cluster + acb->nb_sectors;
1456
    if (s->crypt_method &&
1457
        n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
1458
        n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
1459

    
1460
    acb->cluster_offset = alloc_cluster_offset(bs, acb->sector_num << 9,
1461
                                          index_in_cluster,
1462
                                          n_end, &acb->n, &acb->l2meta);
1463
    if (!acb->cluster_offset || (acb->cluster_offset & 511) != 0) {
1464
        ret = -EIO;
1465
        goto done;
1466
    }
1467
    if (s->crypt_method) {
1468
        if (!acb->cluster_data) {
1469
            acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
1470
                                             s->cluster_size);
1471
        }
1472
        encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
1473
                        acb->n, 1, &s->aes_encrypt_key);
1474
        src_buf = acb->cluster_data;
1475
    } else {
1476
        src_buf = acb->buf;
1477
    }
1478
    acb->hd_iov.iov_base = (void *)src_buf;
1479
    acb->hd_iov.iov_len = acb->n * 512;
1480
    qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
1481
    acb->hd_aiocb = bdrv_aio_writev(s->hd,
1482
                                    (acb->cluster_offset >> 9) + index_in_cluster,
1483
                                    &acb->hd_qiov, acb->n,
1484
                                    qcow_aio_write_cb, acb);
1485
    if (acb->hd_aiocb == NULL)
1486
        goto done;
1487

    
1488
    return;
1489

    
1490
done:
1491
    if (acb->qiov->niov > 1)
1492
        qemu_vfree(acb->orig_buf);
1493
    acb->common.cb(acb->common.opaque, ret);
1494
    qemu_aio_release(acb);
1495
}
1496

    
1497
static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs,
1498
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
1499
        BlockDriverCompletionFunc *cb, void *opaque)
1500
{
1501
    BDRVQcowState *s = bs->opaque;
1502
    QCowAIOCB *acb;
1503

    
1504
    s->cluster_cache_offset = -1; /* disable compressed cache */
1505

    
1506
    acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
1507
    if (!acb)
1508
        return NULL;
1509

    
1510
    qcow_aio_write_cb(acb, 0);
1511
    return &acb->common;
1512
}
1513

    
1514
static void qcow_close(BlockDriverState *bs)
1515
{
1516
    BDRVQcowState *s = bs->opaque;
1517
    qemu_free(s->l1_table);
1518
    qemu_free(s->l2_cache);
1519
    qemu_free(s->cluster_cache);
1520
    qemu_free(s->cluster_data);
1521
    refcount_close(bs);
1522
    bdrv_delete(s->hd);
1523
}
1524

    
1525
/* XXX: use std qcow open function ? */
1526
typedef struct QCowCreateState {
1527
    int cluster_size;
1528
    int cluster_bits;
1529
    uint16_t *refcount_block;
1530
    uint64_t *refcount_table;
1531
    int64_t l1_table_offset;
1532
    int64_t refcount_table_offset;
1533
    int64_t refcount_block_offset;
1534
} QCowCreateState;
1535

    
1536
static void create_refcount_update(QCowCreateState *s,
1537
                                   int64_t offset, int64_t size)
1538
{
1539
    int refcount;
1540
    int64_t start, last, cluster_offset;
1541
    uint16_t *p;
1542

    
1543
    start = offset & ~(s->cluster_size - 1);
1544
    last = (offset + size - 1)  & ~(s->cluster_size - 1);
1545
    for(cluster_offset = start; cluster_offset <= last;
1546
        cluster_offset += s->cluster_size) {
1547
        p = &s->refcount_block[cluster_offset >> s->cluster_bits];
1548
        refcount = be16_to_cpu(*p);
1549
        refcount++;
1550
        *p = cpu_to_be16(refcount);
1551
    }
1552
}
1553

    
1554
static int get_bits_from_size(size_t size)
1555
{
1556
    int res = 0;
1557

    
1558
    if (size == 0) {
1559
        return -1;
1560
    }
1561

    
1562
    while (size != 1) {
1563
        /* Not a power of two */
1564
        if (size & 1) {
1565
            return -1;
1566
        }
1567

    
1568
        size >>= 1;
1569
        res++;
1570
    }
1571

    
1572
    return res;
1573
}
1574

    
1575
static int qcow_create2(const char *filename, int64_t total_size,
1576
                        const char *backing_file, const char *backing_format,
1577
                        int flags, size_t cluster_size)
1578
{
1579

    
1580
    int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
1581
    int ref_clusters, backing_format_len = 0;
1582
    QCowHeader header;
1583
    uint64_t tmp, offset;
1584
    QCowCreateState s1, *s = &s1;
1585
    QCowExtension ext_bf = {0, 0};
1586

    
1587

    
1588
    memset(s, 0, sizeof(*s));
1589

    
1590
    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
1591
    if (fd < 0)
1592
        return -1;
1593
    memset(&header, 0, sizeof(header));
1594
    header.magic = cpu_to_be32(QCOW_MAGIC);
1595
    header.version = cpu_to_be32(QCOW_VERSION);
1596
    header.size = cpu_to_be64(total_size * 512);
1597
    header_size = sizeof(header);
1598
    backing_filename_len = 0;
1599
    if (backing_file) {
1600
        if (backing_format) {
1601
            ext_bf.magic = QCOW_EXT_MAGIC_BACKING_FORMAT;
1602
            backing_format_len = strlen(backing_format);
1603
            ext_bf.len = (backing_format_len + 7) & ~7;
1604
            header_size += ((sizeof(ext_bf) + ext_bf.len + 7) & ~7);
1605
        }
1606
        header.backing_file_offset = cpu_to_be64(header_size);
1607
        backing_filename_len = strlen(backing_file);
1608
        header.backing_file_size = cpu_to_be32(backing_filename_len);
1609
        header_size += backing_filename_len;
1610
    }
1611

    
1612
    /* Cluster size */
1613
    s->cluster_bits = get_bits_from_size(cluster_size);
1614
    if (s->cluster_bits < MIN_CLUSTER_BITS ||
1615
        s->cluster_bits > MAX_CLUSTER_BITS)
1616
    {
1617
        fprintf(stderr, "Cluster size must be a power of two between "
1618
            "%d and %dk\n",
1619
            1 << MIN_CLUSTER_BITS,
1620
            1 << (MAX_CLUSTER_BITS - 10));
1621
        return -EINVAL;
1622
    }
1623
    s->cluster_size = 1 << s->cluster_bits;
1624

    
1625
    header.cluster_bits = cpu_to_be32(s->cluster_bits);
1626
    header_size = (header_size + 7) & ~7;
1627
    if (flags & BLOCK_FLAG_ENCRYPT) {
1628
        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
1629
    } else {
1630
        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
1631
    }
1632
    l2_bits = s->cluster_bits - 3;
1633
    shift = s->cluster_bits + l2_bits;
1634
    l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
1635
    offset = align_offset(header_size, s->cluster_size);
1636
    s->l1_table_offset = offset;
1637
    header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
1638
    header.l1_size = cpu_to_be32(l1_size);
1639
    offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
1640

    
1641
    s->refcount_table = qemu_mallocz(s->cluster_size);
1642

    
1643
    s->refcount_table_offset = offset;
1644
    header.refcount_table_offset = cpu_to_be64(offset);
1645
    header.refcount_table_clusters = cpu_to_be32(1);
1646
    offset += s->cluster_size;
1647
    s->refcount_block_offset = offset;
1648

    
1649
    /* count how many refcount blocks needed */
1650
    tmp = offset >> s->cluster_bits;
1651
    ref_clusters = (tmp >> (s->cluster_bits - REFCOUNT_SHIFT)) + 1;
1652
    for (i=0; i < ref_clusters; i++) {
1653
        s->refcount_table[i] = cpu_to_be64(offset);
1654
        offset += s->cluster_size;
1655
    }
1656

    
1657
    s->refcount_block = qemu_mallocz(ref_clusters * s->cluster_size);
1658

    
1659
    /* update refcounts */
1660
    create_refcount_update(s, 0, header_size);
1661
    create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t));
1662
    create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
1663
    create_refcount_update(s, s->refcount_block_offset, ref_clusters * s->cluster_size);
1664

    
1665
    /* write all the data */
1666
    write(fd, &header, sizeof(header));
1667
    if (backing_file) {
1668
        if (backing_format_len) {
1669
            char zero[16];
1670
            int d = ext_bf.len - backing_format_len;
1671

    
1672
            memset(zero, 0, sizeof(zero));
1673
            cpu_to_be32s(&ext_bf.magic);
1674
            cpu_to_be32s(&ext_bf.len);
1675
            write(fd, &ext_bf, sizeof(ext_bf));
1676
            write(fd, backing_format, backing_format_len);
1677
            if (d>0) {
1678
                write(fd, zero, d);
1679
            }
1680
        }
1681
        write(fd, backing_file, backing_filename_len);
1682
    }
1683
    lseek(fd, s->l1_table_offset, SEEK_SET);
1684
    tmp = 0;
1685
    for(i = 0;i < l1_size; i++) {
1686
        write(fd, &tmp, sizeof(tmp));
1687
    }
1688
    lseek(fd, s->refcount_table_offset, SEEK_SET);
1689
    write(fd, s->refcount_table, s->cluster_size);
1690

    
1691
    lseek(fd, s->refcount_block_offset, SEEK_SET);
1692
    write(fd, s->refcount_block, ref_clusters * s->cluster_size);
1693

    
1694
    qemu_free(s->refcount_table);
1695
    qemu_free(s->refcount_block);
1696
    close(fd);
1697
    return 0;
1698
}
1699

    
1700
static int qcow_create(const char *filename, QEMUOptionParameter *options)
1701
{
1702
    const char *backing_file = NULL;
1703
    const char *backing_fmt = NULL;
1704
    uint64_t sectors = 0;
1705
    int flags = 0;
1706
    size_t cluster_size = 65536;
1707

    
1708
    /* Read out options */
1709
    while (options && options->name) {
1710
        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
1711
            sectors = options->value.n / 512;
1712
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
1713
            backing_file = options->value.s;
1714
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
1715
            backing_fmt = options->value.s;
1716
        } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
1717
            flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
1718
        } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
1719
            if (options->value.n) {
1720
                cluster_size = options->value.n;
1721
            }
1722
        }
1723
        options++;
1724
    }
1725

    
1726
    return qcow_create2(filename, sectors, backing_file, backing_fmt, flags,
1727
        cluster_size);
1728
}
1729

    
1730
static int qcow_make_empty(BlockDriverState *bs)
1731
{
1732
#if 0
1733
    /* XXX: not correct */
1734
    BDRVQcowState *s = bs->opaque;
1735
    uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1736
    int ret;
1737

1738
    memset(s->l1_table, 0, l1_length);
1739
    if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
1740
        return -1;
1741
    ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
1742
    if (ret < 0)
1743
        return ret;
1744

1745
    l2_cache_reset(bs);
1746
#endif
1747
    return 0;
1748
}
1749

    
1750
/* XXX: put compressed sectors first, then all the cluster aligned
1751
   tables to avoid losing bytes in alignment */
1752
static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
1753
                                 const uint8_t *buf, int nb_sectors)
1754
{
1755
    BDRVQcowState *s = bs->opaque;
1756
    z_stream strm;
1757
    int ret, out_len;
1758
    uint8_t *out_buf;
1759
    uint64_t cluster_offset;
1760

    
1761
    if (nb_sectors == 0) {
1762
        /* align end of file to a sector boundary to ease reading with
1763
           sector based I/Os */
1764
        cluster_offset = bdrv_getlength(s->hd);
1765
        cluster_offset = (cluster_offset + 511) & ~511;
1766
        bdrv_truncate(s->hd, cluster_offset);
1767
        return 0;
1768
    }
1769

    
1770
    if (nb_sectors != s->cluster_sectors)
1771
        return -EINVAL;
1772

    
1773
    out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
1774

    
1775
    /* best compression, small window, no zlib header */
1776
    memset(&strm, 0, sizeof(strm));
1777
    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1778
                       Z_DEFLATED, -12,
1779
                       9, Z_DEFAULT_STRATEGY);
1780
    if (ret != 0) {
1781
        qemu_free(out_buf);
1782
        return -1;
1783
    }
1784

    
1785
    strm.avail_in = s->cluster_size;
1786
    strm.next_in = (uint8_t *)buf;
1787
    strm.avail_out = s->cluster_size;
1788
    strm.next_out = out_buf;
1789

    
1790
    ret = deflate(&strm, Z_FINISH);
1791
    if (ret != Z_STREAM_END && ret != Z_OK) {
1792
        qemu_free(out_buf);
1793
        deflateEnd(&strm);
1794
        return -1;
1795
    }
1796
    out_len = strm.next_out - out_buf;
1797

    
1798
    deflateEnd(&strm);
1799

    
1800
    if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1801
        /* could not compress: write normal cluster */
1802
        bdrv_write(bs, sector_num, buf, s->cluster_sectors);
1803
    } else {
1804
        cluster_offset = alloc_compressed_cluster_offset(bs, sector_num << 9,
1805
                                              out_len);
1806
        if (!cluster_offset)
1807
            return -1;
1808
        cluster_offset &= s->cluster_offset_mask;
1809
        if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
1810
            qemu_free(out_buf);
1811
            return -1;
1812
        }
1813
    }
1814

    
1815
    qemu_free(out_buf);
1816
    return 0;
1817
}
1818

    
1819
static void qcow_flush(BlockDriverState *bs)
1820
{
1821
    BDRVQcowState *s = bs->opaque;
1822
    bdrv_flush(s->hd);
1823
}
1824

    
1825
static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1826
{
1827
    BDRVQcowState *s = bs->opaque;
1828
    bdi->cluster_size = s->cluster_size;
1829
    bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
1830
        (s->cluster_bits + s->l2_bits);
1831
    return 0;
1832
}
1833

    
1834
/*********************************************************/
1835
/* snapshot support */
1836

    
1837
/* update the refcounts of snapshots and the copied flag */
1838
static int update_snapshot_refcount(BlockDriverState *bs,
1839
                                    int64_t l1_table_offset,
1840
                                    int l1_size,
1841
                                    int addend)
1842
{
1843
    BDRVQcowState *s = bs->opaque;
1844
    uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
1845
    int64_t old_offset, old_l2_offset;
1846
    int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
1847

    
1848
    l2_cache_reset(bs);
1849

    
1850
    l2_table = NULL;
1851
    l1_table = NULL;
1852
    l1_size2 = l1_size * sizeof(uint64_t);
1853
    l1_allocated = 0;
1854
    if (l1_table_offset != s->l1_table_offset) {
1855
        l1_table = qemu_malloc(l1_size2);
1856
        l1_allocated = 1;
1857
        if (bdrv_pread(s->hd, l1_table_offset,
1858
                       l1_table, l1_size2) != l1_size2)
1859
            goto fail;
1860
        for(i = 0;i < l1_size; i++)
1861
            be64_to_cpus(&l1_table[i]);
1862
    } else {
1863
        assert(l1_size == s->l1_size);
1864
        l1_table = s->l1_table;
1865
        l1_allocated = 0;
1866
    }
1867

    
1868
    l2_size = s->l2_size * sizeof(uint64_t);
1869
    l2_table = qemu_malloc(l2_size);
1870
    l1_modified = 0;
1871
    for(i = 0; i < l1_size; i++) {
1872
        l2_offset = l1_table[i];
1873
        if (l2_offset) {
1874
            old_l2_offset = l2_offset;
1875
            l2_offset &= ~QCOW_OFLAG_COPIED;
1876
            l2_modified = 0;
1877
            if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
1878
                goto fail;
1879
            for(j = 0; j < s->l2_size; j++) {
1880
                offset = be64_to_cpu(l2_table[j]);
1881
                if (offset != 0) {
1882
                    old_offset = offset;
1883
                    offset &= ~QCOW_OFLAG_COPIED;
1884
                    if (offset & QCOW_OFLAG_COMPRESSED) {
1885
                        nb_csectors = ((offset >> s->csize_shift) &
1886
                                       s->csize_mask) + 1;
1887
                        if (addend != 0)
1888
                            update_refcount(bs, (offset & s->cluster_offset_mask) & ~511,
1889
                                            nb_csectors * 512, addend);
1890
                        /* compressed clusters are never modified */
1891
                        refcount = 2;
1892
                    } else {
1893
                        if (addend != 0) {
1894
                            refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend);
1895
                        } else {
1896
                            refcount = get_refcount(bs, offset >> s->cluster_bits);
1897
                        }
1898
                    }
1899

    
1900
                    if (refcount == 1) {
1901
                        offset |= QCOW_OFLAG_COPIED;
1902
                    }
1903
                    if (offset != old_offset) {
1904
                        l2_table[j] = cpu_to_be64(offset);
1905
                        l2_modified = 1;
1906
                    }
1907
                }
1908
            }
1909
            if (l2_modified) {
1910
                if (bdrv_pwrite(s->hd,
1911
                                l2_offset, l2_table, l2_size) != l2_size)
1912
                    goto fail;
1913
            }
1914

    
1915
            if (addend != 0) {
1916
                refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend);
1917
            } else {
1918
                refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
1919
            }
1920
            if (refcount == 1) {
1921
                l2_offset |= QCOW_OFLAG_COPIED;
1922
            }
1923
            if (l2_offset != old_l2_offset) {
1924
                l1_table[i] = l2_offset;
1925
                l1_modified = 1;
1926
            }
1927
        }
1928
    }
1929
    if (l1_modified) {
1930
        for(i = 0; i < l1_size; i++)
1931
            cpu_to_be64s(&l1_table[i]);
1932
        if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
1933
                        l1_size2) != l1_size2)
1934
            goto fail;
1935
        for(i = 0; i < l1_size; i++)
1936
            be64_to_cpus(&l1_table[i]);
1937
    }
1938
    if (l1_allocated)
1939
        qemu_free(l1_table);
1940
    qemu_free(l2_table);
1941
    return 0;
1942
 fail:
1943
    if (l1_allocated)
1944
        qemu_free(l1_table);
1945
    qemu_free(l2_table);
1946
    return -EIO;
1947
}
1948

    
1949
static void qcow_free_snapshots(BlockDriverState *bs)
1950
{
1951
    BDRVQcowState *s = bs->opaque;
1952
    int i;
1953

    
1954
    for(i = 0; i < s->nb_snapshots; i++) {
1955
        qemu_free(s->snapshots[i].name);
1956
        qemu_free(s->snapshots[i].id_str);
1957
    }
1958
    qemu_free(s->snapshots);
1959
    s->snapshots = NULL;
1960
    s->nb_snapshots = 0;
1961
}
1962

    
1963
static int qcow_read_snapshots(BlockDriverState *bs)
1964
{
1965
    BDRVQcowState *s = bs->opaque;
1966
    QCowSnapshotHeader h;
1967
    QCowSnapshot *sn;
1968
    int i, id_str_size, name_size;
1969
    int64_t offset;
1970
    uint32_t extra_data_size;
1971

    
1972
    if (!s->nb_snapshots) {
1973
        s->snapshots = NULL;
1974
        s->snapshots_size = 0;
1975
        return 0;
1976
    }
1977

    
1978
    offset = s->snapshots_offset;
1979
    s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
1980
    for(i = 0; i < s->nb_snapshots; i++) {
1981
        offset = align_offset(offset, 8);
1982
        if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h))
1983
            goto fail;
1984
        offset += sizeof(h);
1985
        sn = s->snapshots + i;
1986
        sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
1987
        sn->l1_size = be32_to_cpu(h.l1_size);
1988
        sn->vm_state_size = be32_to_cpu(h.vm_state_size);
1989
        sn->date_sec = be32_to_cpu(h.date_sec);
1990
        sn->date_nsec = be32_to_cpu(h.date_nsec);
1991
        sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
1992
        extra_data_size = be32_to_cpu(h.extra_data_size);
1993

    
1994
        id_str_size = be16_to_cpu(h.id_str_size);
1995
        name_size = be16_to_cpu(h.name_size);
1996

    
1997
        offset += extra_data_size;
1998

    
1999
        sn->id_str = qemu_malloc(id_str_size + 1);
2000
        if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
2001
            goto fail;
2002
        offset += id_str_size;
2003
        sn->id_str[id_str_size] = '\0';
2004

    
2005
        sn->name = qemu_malloc(name_size + 1);
2006
        if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size)
2007
            goto fail;
2008
        offset += name_size;
2009
        sn->name[name_size] = '\0';
2010
    }
2011
    s->snapshots_size = offset - s->snapshots_offset;
2012
    return 0;
2013
 fail:
2014
    qcow_free_snapshots(bs);
2015
    return -1;
2016
}
2017

    
2018
/* add at the end of the file a new list of snapshots */
2019
static int qcow_write_snapshots(BlockDriverState *bs)
2020
{
2021
    BDRVQcowState *s = bs->opaque;
2022
    QCowSnapshot *sn;
2023
    QCowSnapshotHeader h;
2024
    int i, name_size, id_str_size, snapshots_size;
2025
    uint64_t data64;
2026
    uint32_t data32;
2027
    int64_t offset, snapshots_offset;
2028

    
2029
    /* compute the size of the snapshots */
2030
    offset = 0;
2031
    for(i = 0; i < s->nb_snapshots; i++) {
2032
        sn = s->snapshots + i;
2033
        offset = align_offset(offset, 8);
2034
        offset += sizeof(h);
2035
        offset += strlen(sn->id_str);
2036
        offset += strlen(sn->name);
2037
    }
2038
    snapshots_size = offset;
2039

    
2040
    snapshots_offset = alloc_clusters(bs, snapshots_size);
2041
    offset = snapshots_offset;
2042

    
2043
    for(i = 0; i < s->nb_snapshots; i++) {
2044
        sn = s->snapshots + i;
2045
        memset(&h, 0, sizeof(h));
2046
        h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
2047
        h.l1_size = cpu_to_be32(sn->l1_size);
2048
        h.vm_state_size = cpu_to_be32(sn->vm_state_size);
2049
        h.date_sec = cpu_to_be32(sn->date_sec);
2050
        h.date_nsec = cpu_to_be32(sn->date_nsec);
2051
        h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
2052

    
2053
        id_str_size = strlen(sn->id_str);
2054
        name_size = strlen(sn->name);
2055
        h.id_str_size = cpu_to_be16(id_str_size);
2056
        h.name_size = cpu_to_be16(name_size);
2057
        offset = align_offset(offset, 8);
2058
        if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h))
2059
            goto fail;
2060
        offset += sizeof(h);
2061
        if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
2062
            goto fail;
2063
        offset += id_str_size;
2064
        if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size)
2065
            goto fail;
2066
        offset += name_size;
2067
    }
2068

    
2069
    /* update the various header fields */
2070
    data64 = cpu_to_be64(snapshots_offset);
2071
    if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset),
2072
                    &data64, sizeof(data64)) != sizeof(data64))
2073
        goto fail;
2074
    data32 = cpu_to_be32(s->nb_snapshots);
2075
    if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots),
2076
                    &data32, sizeof(data32)) != sizeof(data32))
2077
        goto fail;
2078

    
2079
    /* free the old snapshot table */
2080
    free_clusters(bs, s->snapshots_offset, s->snapshots_size);
2081
    s->snapshots_offset = snapshots_offset;
2082
    s->snapshots_size = snapshots_size;
2083
    return 0;
2084
 fail:
2085
    return -1;
2086
}
2087

    
2088
static void find_new_snapshot_id(BlockDriverState *bs,
2089
                                 char *id_str, int id_str_size)
2090
{
2091
    BDRVQcowState *s = bs->opaque;
2092
    QCowSnapshot *sn;
2093
    int i, id, id_max = 0;
2094

    
2095
    for(i = 0; i < s->nb_snapshots; i++) {
2096
        sn = s->snapshots + i;
2097
        id = strtoul(sn->id_str, NULL, 10);
2098
        if (id > id_max)
2099
            id_max = id;
2100
    }
2101
    snprintf(id_str, id_str_size, "%d", id_max + 1);
2102
}
2103

    
2104
static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
2105
{
2106
    BDRVQcowState *s = bs->opaque;
2107
    int i;
2108

    
2109
    for(i = 0; i < s->nb_snapshots; i++) {
2110
        if (!strcmp(s->snapshots[i].id_str, id_str))
2111
            return i;
2112
    }
2113
    return -1;
2114
}
2115

    
2116
static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
2117
{
2118
    BDRVQcowState *s = bs->opaque;
2119
    int i, ret;
2120

    
2121
    ret = find_snapshot_by_id(bs, name);
2122
    if (ret >= 0)
2123
        return ret;
2124
    for(i = 0; i < s->nb_snapshots; i++) {
2125
        if (!strcmp(s->snapshots[i].name, name))
2126
            return i;
2127
    }
2128
    return -1;
2129
}
2130

    
2131
/* if no id is provided, a new one is constructed */
2132
static int qcow_snapshot_create(BlockDriverState *bs,
2133
                                QEMUSnapshotInfo *sn_info)
2134
{
2135
    BDRVQcowState *s = bs->opaque;
2136
    QCowSnapshot *snapshots1, sn1, *sn = &sn1;
2137
    int i, ret;
2138
    uint64_t *l1_table = NULL;
2139

    
2140
    memset(sn, 0, sizeof(*sn));
2141

    
2142
    if (sn_info->id_str[0] == '\0') {
2143
        /* compute a new id */
2144
        find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
2145
    }
2146

    
2147
    /* check that the ID is unique */
2148
    if (find_snapshot_by_id(bs, sn_info->id_str) >= 0)
2149
        return -ENOENT;
2150

    
2151
    sn->id_str = qemu_strdup(sn_info->id_str);
2152
    if (!sn->id_str)
2153
        goto fail;
2154
    sn->name = qemu_strdup(sn_info->name);
2155
    if (!sn->name)
2156
        goto fail;
2157
    sn->vm_state_size = sn_info->vm_state_size;
2158
    sn->date_sec = sn_info->date_sec;
2159
    sn->date_nsec = sn_info->date_nsec;
2160
    sn->vm_clock_nsec = sn_info->vm_clock_nsec;
2161

    
2162
    ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
2163
    if (ret < 0)
2164
        goto fail;
2165

    
2166
    /* create the L1 table of the snapshot */
2167
    sn->l1_table_offset = alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
2168
    sn->l1_size = s->l1_size;
2169

    
2170
    l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
2171
    for(i = 0; i < s->l1_size; i++) {
2172
        l1_table[i] = cpu_to_be64(s->l1_table[i]);
2173
    }
2174
    if (bdrv_pwrite(s->hd, sn->l1_table_offset,
2175
                    l1_table, s->l1_size * sizeof(uint64_t)) !=
2176
        (s->l1_size * sizeof(uint64_t)))
2177
        goto fail;
2178
    qemu_free(l1_table);
2179
    l1_table = NULL;
2180

    
2181
    snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
2182
    if (s->snapshots) {
2183
        memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
2184
        qemu_free(s->snapshots);
2185
    }
2186
    s->snapshots = snapshots1;
2187
    s->snapshots[s->nb_snapshots++] = *sn;
2188

    
2189
    if (qcow_write_snapshots(bs) < 0)
2190
        goto fail;
2191
#ifdef DEBUG_ALLOC
2192
    check_refcounts(bs);
2193
#endif
2194
    return 0;
2195
 fail:
2196
    qemu_free(sn->name);
2197
    qemu_free(l1_table);
2198
    return -1;
2199
}
2200

    
2201
/* copy the snapshot 'snapshot_name' into the current disk image */
2202
static int qcow_snapshot_goto(BlockDriverState *bs,
2203
                              const char *snapshot_id)
2204
{
2205
    BDRVQcowState *s = bs->opaque;
2206
    QCowSnapshot *sn;
2207
    int i, snapshot_index, l1_size2;
2208

    
2209
    snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
2210
    if (snapshot_index < 0)
2211
        return -ENOENT;
2212
    sn = &s->snapshots[snapshot_index];
2213

    
2214
    if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
2215
        goto fail;
2216

    
2217
    if (grow_l1_table(bs, sn->l1_size) < 0)
2218
        goto fail;
2219

    
2220
    s->l1_size = sn->l1_size;
2221
    l1_size2 = s->l1_size * sizeof(uint64_t);
2222
    /* copy the snapshot l1 table to the current l1 table */
2223
    if (bdrv_pread(s->hd, sn->l1_table_offset,
2224
                   s->l1_table, l1_size2) != l1_size2)
2225
        goto fail;
2226
    if (bdrv_pwrite(s->hd, s->l1_table_offset,
2227
                    s->l1_table, l1_size2) != l1_size2)
2228
        goto fail;
2229
    for(i = 0;i < s->l1_size; i++) {
2230
        be64_to_cpus(&s->l1_table[i]);
2231
    }
2232

    
2233
    if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
2234
        goto fail;
2235

    
2236
#ifdef DEBUG_ALLOC
2237
    check_refcounts(bs);
2238
#endif
2239
    return 0;
2240
 fail:
2241
    return -EIO;
2242
}
2243

    
2244
static int qcow_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
2245
{
2246
    BDRVQcowState *s = bs->opaque;
2247
    QCowSnapshot *sn;
2248
    int snapshot_index, ret;
2249

    
2250
    snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
2251
    if (snapshot_index < 0)
2252
        return -ENOENT;
2253
    sn = &s->snapshots[snapshot_index];
2254

    
2255
    ret = update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
2256
    if (ret < 0)
2257
        return ret;
2258
    /* must update the copied flag on the current cluster offsets */
2259
    ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
2260
    if (ret < 0)
2261
        return ret;
2262
    free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
2263

    
2264
    qemu_free(sn->id_str);
2265
    qemu_free(sn->name);
2266
    memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
2267
    s->nb_snapshots--;
2268
    ret = qcow_write_snapshots(bs);
2269
    if (ret < 0) {
2270
        /* XXX: restore snapshot if error ? */
2271
        return ret;
2272
    }
2273
#ifdef DEBUG_ALLOC
2274
    check_refcounts(bs);
2275
#endif
2276
    return 0;
2277
}
2278

    
2279
static int qcow_snapshot_list(BlockDriverState *bs,
2280
                              QEMUSnapshotInfo **psn_tab)
2281
{
2282
    BDRVQcowState *s = bs->opaque;
2283
    QEMUSnapshotInfo *sn_tab, *sn_info;
2284
    QCowSnapshot *sn;
2285
    int i;
2286

    
2287
    if (!s->nb_snapshots) {
2288
        *psn_tab = NULL;
2289
        return s->nb_snapshots;
2290
    }
2291

    
2292
    sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
2293
    for(i = 0; i < s->nb_snapshots; i++) {
2294
        sn_info = sn_tab + i;
2295
        sn = s->snapshots + i;
2296
        pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
2297
                sn->id_str);
2298
        pstrcpy(sn_info->name, sizeof(sn_info->name),
2299
                sn->name);
2300
        sn_info->vm_state_size = sn->vm_state_size;
2301
        sn_info->date_sec = sn->date_sec;
2302
        sn_info->date_nsec = sn->date_nsec;
2303
        sn_info->vm_clock_nsec = sn->vm_clock_nsec;
2304
    }
2305
    *psn_tab = sn_tab;
2306
    return s->nb_snapshots;
2307
}
2308

    
2309
/*********************************************************/
2310
/* refcount handling */
2311

    
2312
static int refcount_init(BlockDriverState *bs)
2313
{
2314
    BDRVQcowState *s = bs->opaque;
2315
    int ret, refcount_table_size2, i;
2316

    
2317
    s->refcount_block_cache = qemu_malloc(s->cluster_size);
2318
    refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
2319
    s->refcount_table = qemu_malloc(refcount_table_size2);
2320
    if (s->refcount_table_size > 0) {
2321
        ret = bdrv_pread(s->hd, s->refcount_table_offset,
2322
                         s->refcount_table, refcount_table_size2);
2323
        if (ret != refcount_table_size2)
2324
            goto fail;
2325
        for(i = 0; i < s->refcount_table_size; i++)
2326
            be64_to_cpus(&s->refcount_table[i]);
2327
    }
2328
    return 0;
2329
 fail:
2330
    return -ENOMEM;
2331
}
2332

    
2333
static void refcount_close(BlockDriverState *bs)
2334
{
2335
    BDRVQcowState *s = bs->opaque;
2336
    qemu_free(s->refcount_block_cache);
2337
    qemu_free(s->refcount_table);
2338
}
2339

    
2340

    
2341
static int load_refcount_block(BlockDriverState *bs,
2342
                               int64_t refcount_block_offset)
2343
{
2344
    BDRVQcowState *s = bs->opaque;
2345
    int ret;
2346
    ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache,
2347
                     s->cluster_size);
2348
    if (ret != s->cluster_size)
2349
        return -EIO;
2350
    s->refcount_block_cache_offset = refcount_block_offset;
2351
    return 0;
2352
}
2353

    
2354
static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
2355
{
2356
    BDRVQcowState *s = bs->opaque;
2357
    int refcount_table_index, block_index;
2358
    int64_t refcount_block_offset;
2359

    
2360
    refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
2361
    if (refcount_table_index >= s->refcount_table_size)
2362
        return 0;
2363
    refcount_block_offset = s->refcount_table[refcount_table_index];
2364
    if (!refcount_block_offset)
2365
        return 0;
2366
    if (refcount_block_offset != s->refcount_block_cache_offset) {
2367
        /* better than nothing: return allocated if read error */
2368
        if (load_refcount_block(bs, refcount_block_offset) < 0)
2369
            return 1;
2370
    }
2371
    block_index = cluster_index &
2372
        ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
2373
    return be16_to_cpu(s->refcount_block_cache[block_index]);
2374
}
2375

    
2376
/* return < 0 if error */
2377
static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
2378
{
2379
    BDRVQcowState *s = bs->opaque;
2380
    int i, nb_clusters;
2381

    
2382
    nb_clusters = size_to_clusters(s, size);
2383
retry:
2384
    for(i = 0; i < nb_clusters; i++) {
2385
        int64_t i = s->free_cluster_index++;
2386
        if (get_refcount(bs, i) != 0)
2387
            goto retry;
2388
    }
2389
#ifdef DEBUG_ALLOC2
2390
    printf("alloc_clusters: size=%lld -> %lld\n",
2391
            size,
2392
            (s->free_cluster_index - nb_clusters) << s->cluster_bits);
2393
#endif
2394
    return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
2395
}
2396

    
2397
static int64_t alloc_clusters(BlockDriverState *bs, int64_t size)
2398
{
2399
    int64_t offset;
2400

    
2401
    offset = alloc_clusters_noref(bs, size);
2402
    update_refcount(bs, offset, size, 1);
2403
    return offset;
2404
}
2405

    
2406
/* only used to allocate compressed sectors. We try to allocate
2407
   contiguous sectors. size must be <= cluster_size */
2408
static int64_t alloc_bytes(BlockDriverState *bs, int size)
2409
{
2410
    BDRVQcowState *s = bs->opaque;
2411
    int64_t offset, cluster_offset;
2412
    int free_in_cluster;
2413

    
2414
    assert(size > 0 && size <= s->cluster_size);
2415
    if (s->free_byte_offset == 0) {
2416
        s->free_byte_offset = alloc_clusters(bs, s->cluster_size);
2417
    }
2418
 redo:
2419
    free_in_cluster = s->cluster_size -
2420
        (s->free_byte_offset & (s->cluster_size - 1));
2421
    if (size <= free_in_cluster) {
2422
        /* enough space in current cluster */
2423
        offset = s->free_byte_offset;
2424
        s->free_byte_offset += size;
2425
        free_in_cluster -= size;
2426
        if (free_in_cluster == 0)
2427
            s->free_byte_offset = 0;
2428
        if ((offset & (s->cluster_size - 1)) != 0)
2429
            update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
2430
    } else {
2431
        offset = alloc_clusters(bs, s->cluster_size);
2432
        cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
2433
        if ((cluster_offset + s->cluster_size) == offset) {
2434
            /* we are lucky: contiguous data */
2435
            offset = s->free_byte_offset;
2436
            update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
2437
            s->free_byte_offset += size;
2438
        } else {
2439
            s->free_byte_offset = offset;
2440
            goto redo;
2441
        }
2442
    }
2443
    return offset;
2444
}
2445

    
2446
static void free_clusters(BlockDriverState *bs,
2447
                          int64_t offset, int64_t size)
2448
{
2449
    update_refcount(bs, offset, size, -1);
2450
}
2451

    
2452
static int grow_refcount_table(BlockDriverState *bs, int min_size)
2453
{
2454
    BDRVQcowState *s = bs->opaque;
2455
    int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
2456
    uint64_t *new_table;
2457
    int64_t table_offset;
2458
    uint8_t data[12];
2459
    int old_table_size;
2460
    int64_t old_table_offset;
2461

    
2462
    if (min_size <= s->refcount_table_size)
2463
        return 0;
2464
    /* compute new table size */
2465
    refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
2466
    for(;;) {
2467
        if (refcount_table_clusters == 0) {
2468
            refcount_table_clusters = 1;
2469
        } else {
2470
            refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2;
2471
        }
2472
        new_table_size = refcount_table_clusters << (s->cluster_bits - 3);
2473
        if (min_size <= new_table_size)
2474
            break;
2475
    }
2476
#ifdef DEBUG_ALLOC2
2477
    printf("grow_refcount_table from %d to %d\n",
2478
           s->refcount_table_size,
2479
           new_table_size);
2480
#endif
2481
    new_table_size2 = new_table_size * sizeof(uint64_t);
2482
    new_table = qemu_mallocz(new_table_size2);
2483
    memcpy(new_table, s->refcount_table,
2484
           s->refcount_table_size * sizeof(uint64_t));
2485
    for(i = 0; i < s->refcount_table_size; i++)
2486
        cpu_to_be64s(&new_table[i]);
2487
    /* Note: we cannot update the refcount now to avoid recursion */
2488
    table_offset = alloc_clusters_noref(bs, new_table_size2);
2489
    ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2);
2490
    if (ret != new_table_size2)
2491
        goto fail;
2492
    for(i = 0; i < s->refcount_table_size; i++)
2493
        be64_to_cpus(&new_table[i]);
2494

    
2495
    cpu_to_be64w((uint64_t*)data, table_offset);
2496
    cpu_to_be32w((uint32_t*)(data + 8), refcount_table_clusters);
2497
    if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset),
2498
                    data, sizeof(data)) != sizeof(data))
2499
        goto fail;
2500
    qemu_free(s->refcount_table);
2501
    old_table_offset = s->refcount_table_offset;
2502
    old_table_size = s->refcount_table_size;
2503
    s->refcount_table = new_table;
2504
    s->refcount_table_size = new_table_size;
2505
    s->refcount_table_offset = table_offset;
2506

    
2507
    update_refcount(bs, table_offset, new_table_size2, 1);
2508
    free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
2509
    return 0;
2510
 fail:
2511
    free_clusters(bs, table_offset, new_table_size2);
2512
    qemu_free(new_table);
2513
    return -EIO;
2514
}
2515

    
2516

    
2517
static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
2518
{
2519
    BDRVQcowState *s = bs->opaque;
2520
    int64_t offset, refcount_block_offset;
2521
    int ret, refcount_table_index;
2522
    uint64_t data64;
2523

    
2524
    /* Find L1 index and grow refcount table if needed */
2525
    refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
2526
    if (refcount_table_index >= s->refcount_table_size) {
2527
        ret = grow_refcount_table(bs, refcount_table_index + 1);
2528
        if (ret < 0)
2529
            return ret;
2530
    }
2531

    
2532
    /* Load or allocate the refcount block */
2533
    refcount_block_offset = s->refcount_table[refcount_table_index];
2534
    if (!refcount_block_offset) {
2535
        /* create a new refcount block */
2536
        /* Note: we cannot update the refcount now to avoid recursion */
2537
        offset = alloc_clusters_noref(bs, s->cluster_size);
2538
        memset(s->refcount_block_cache, 0, s->cluster_size);
2539
        ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size);
2540
        if (ret != s->cluster_size)
2541
            return -EINVAL;
2542
        s->refcount_table[refcount_table_index] = offset;
2543
        data64 = cpu_to_be64(offset);
2544
        ret = bdrv_pwrite(s->hd, s->refcount_table_offset +
2545
                          refcount_table_index * sizeof(uint64_t),
2546
                          &data64, sizeof(data64));
2547
        if (ret != sizeof(data64))
2548
            return -EINVAL;
2549

    
2550
        refcount_block_offset = offset;
2551
        s->refcount_block_cache_offset = offset;
2552
        update_refcount(bs, offset, s->cluster_size, 1);
2553
    } else {
2554
        if (refcount_block_offset != s->refcount_block_cache_offset) {
2555
            if (load_refcount_block(bs, refcount_block_offset) < 0)
2556
                return -EIO;
2557
        }
2558
    }
2559

    
2560
    return refcount_block_offset;
2561
}
2562

    
2563
/* addend must be 1 or -1 */
2564
static int update_cluster_refcount(BlockDriverState *bs,
2565
                                   int64_t cluster_index,
2566
                                   int addend)
2567
{
2568
    BDRVQcowState *s = bs->opaque;
2569
    int ret;
2570

    
2571
    ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend);
2572
    if (ret < 0) {
2573
        return ret;
2574
    }
2575

    
2576
    return get_refcount(bs, cluster_index);
2577
}
2578

    
2579
/* XXX: cache several refcount block clusters ? */
2580
static int update_refcount(BlockDriverState *bs,
2581
                            int64_t offset, int64_t length,
2582
                            int addend)
2583
{
2584
    BDRVQcowState *s = bs->opaque;
2585
    int64_t start, last, cluster_offset;
2586
    int64_t refcount_block_offset = 0;
2587
    int64_t table_index = -1, old_table_index;
2588
    int first_index = -1, last_index = -1;
2589

    
2590
#ifdef DEBUG_ALLOC2
2591
    printf("update_refcount: offset=%lld size=%lld addend=%d\n",
2592
           offset, length, addend);
2593
#endif
2594
    if (length <= 0)
2595
        return -EINVAL;
2596
    start = offset & ~(s->cluster_size - 1);
2597
    last = (offset + length - 1) & ~(s->cluster_size - 1);
2598
    for(cluster_offset = start; cluster_offset <= last;
2599
        cluster_offset += s->cluster_size)
2600
    {
2601
        int block_index, refcount;
2602
        int64_t cluster_index = cluster_offset >> s->cluster_bits;
2603

    
2604
        /* Only write refcount block to disk when we are done with it */
2605
        old_table_index = table_index;
2606
        table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
2607
        if ((old_table_index >= 0) && (table_index != old_table_index)) {
2608
            size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
2609
            if (bdrv_pwrite(s->hd,
2610
                refcount_block_offset + (first_index << REFCOUNT_SHIFT),
2611
                &s->refcount_block_cache[first_index], size) != size)
2612
            {
2613
                return -EIO;
2614
            }
2615

    
2616
            first_index = -1;
2617
            last_index = -1;
2618
        }
2619

    
2620
        /* Load the refcount block and allocate it if needed */
2621
        refcount_block_offset = alloc_refcount_block(bs, cluster_index);
2622
        if (refcount_block_offset < 0) {
2623
            return refcount_block_offset;
2624
        }
2625

    
2626
        /* we can update the count and save it */
2627
        block_index = cluster_index &
2628
            ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
2629
        if (first_index == -1 || block_index < first_index) {
2630
            first_index = block_index;
2631
        }
2632
        if (block_index > last_index) {
2633
            last_index = block_index;
2634
        }
2635

    
2636
        refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
2637
        refcount += addend;
2638
        if (refcount < 0 || refcount > 0xffff)
2639
            return -EINVAL;
2640
        if (refcount == 0 && cluster_index < s->free_cluster_index) {
2641
            s->free_cluster_index = cluster_index;
2642
        }
2643
        s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
2644
    }
2645

    
2646
    /* Write last changed block to disk */
2647
    if (refcount_block_offset != 0) {
2648
        size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
2649
        if (bdrv_pwrite(s->hd,
2650
            refcount_block_offset + (first_index << REFCOUNT_SHIFT),
2651
            &s->refcount_block_cache[first_index], size) != size)
2652
        {
2653
            return -EIO;
2654
        }
2655
    }
2656

    
2657
    return 0;
2658
}
2659

    
2660
/*
2661
 * Increases the refcount for a range of clusters in a given refcount table.
2662
 * This is used to construct a temporary refcount table out of L1 and L2 tables
2663
 * which can be compared the the refcount table saved in the image.
2664
 *
2665
 * Returns the number of errors in the image that were found
2666
 */
2667
static int inc_refcounts(BlockDriverState *bs,
2668
                          uint16_t *refcount_table,
2669
                          int refcount_table_size,
2670
                          int64_t offset, int64_t size)
2671
{
2672
    BDRVQcowState *s = bs->opaque;
2673
    int64_t start, last, cluster_offset;
2674
    int k;
2675
    int errors = 0;
2676

    
2677
    if (size <= 0)
2678
        return 0;
2679

    
2680
    start = offset & ~(s->cluster_size - 1);
2681
    last = (offset + size - 1) & ~(s->cluster_size - 1);
2682
    for(cluster_offset = start; cluster_offset <= last;
2683
        cluster_offset += s->cluster_size) {
2684
        k = cluster_offset >> s->cluster_bits;
2685
        if (k < 0 || k >= refcount_table_size) {
2686
            fprintf(stderr, "ERROR: invalid cluster offset=0x%" PRIx64 "\n",
2687
                cluster_offset);
2688
            errors++;
2689
        } else {
2690
            if (++refcount_table[k] == 0) {
2691
                fprintf(stderr, "ERROR: overflow cluster offset=0x%" PRIx64
2692
                    "\n", cluster_offset);
2693
                errors++;
2694
            }
2695
        }
2696
    }
2697

    
2698
    return errors;
2699
}
2700

    
2701
/*
2702
 * Increases the refcount in the given refcount table for the all clusters
2703
 * referenced in the L2 table. While doing so, performs some checks on L2
2704
 * entries.
2705
 *
2706
 * Returns the number of errors found by the checks or -errno if an internal
2707
 * error occurred.
2708
 */
2709
static int check_refcounts_l2(BlockDriverState *bs,
2710
    uint16_t *refcount_table, int refcount_table_size, int64_t l2_offset,
2711
    int check_copied)
2712
{
2713
    BDRVQcowState *s = bs->opaque;
2714
    uint64_t *l2_table, offset;
2715
    int i, l2_size, nb_csectors, refcount;
2716
    int errors = 0;
2717

    
2718
    /* Read L2 table from disk */
2719
    l2_size = s->l2_size * sizeof(uint64_t);
2720
    l2_table = qemu_malloc(l2_size);
2721

    
2722
    if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
2723
        goto fail;
2724

    
2725
    /* Do the actual checks */
2726
    for(i = 0; i < s->l2_size; i++) {
2727
        offset = be64_to_cpu(l2_table[i]);
2728
        if (offset != 0) {
2729
            if (offset & QCOW_OFLAG_COMPRESSED) {
2730
                /* Compressed clusters don't have QCOW_OFLAG_COPIED */
2731
                if (offset & QCOW_OFLAG_COPIED) {
2732
                    fprintf(stderr, "ERROR: cluster %" PRId64 ": "
2733
                        "copied flag must never be set for compressed "
2734
                        "clusters\n", offset >> s->cluster_bits);
2735
                    offset &= ~QCOW_OFLAG_COPIED;
2736
                    errors++;
2737
                }
2738

    
2739
                /* Mark cluster as used */
2740
                nb_csectors = ((offset >> s->csize_shift) &
2741
                               s->csize_mask) + 1;
2742
                offset &= s->cluster_offset_mask;
2743
                errors += inc_refcounts(bs, refcount_table,
2744
                              refcount_table_size,
2745
                              offset & ~511, nb_csectors * 512);
2746
            } else {
2747
                /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
2748
                if (check_copied) {
2749
                    uint64_t entry = offset;
2750
                    offset &= ~QCOW_OFLAG_COPIED;
2751
                    refcount = get_refcount(bs, offset >> s->cluster_bits);
2752
                    if ((refcount == 1) != ((entry & QCOW_OFLAG_COPIED) != 0)) {
2753
                        fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
2754
                            PRIx64 " refcount=%d\n", entry, refcount);
2755
                        errors++;
2756
                    }
2757
                }
2758

    
2759
                /* Mark cluster as used */
2760
                offset &= ~QCOW_OFLAG_COPIED;
2761
                errors += inc_refcounts(bs, refcount_table,
2762
                              refcount_table_size,
2763
                              offset, s->cluster_size);
2764

    
2765
                /* Correct offsets are cluster aligned */
2766
                if (offset & (s->cluster_size - 1)) {
2767
                    fprintf(stderr, "ERROR offset=%" PRIx64 ": Cluster is not "
2768
                        "properly aligned; L2 entry corrupted.\n", offset);
2769
                    errors++;
2770
                }
2771
            }
2772
        }
2773
    }
2774

    
2775
    qemu_free(l2_table);
2776
    return errors;
2777

    
2778
fail:
2779
    fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
2780
    qemu_free(l2_table);
2781
    return -EIO;
2782
}
2783

    
2784
/*
2785
 * Increases the refcount for the L1 table, its L2 tables and all referenced
2786
 * clusters in the given refcount table. While doing so, performs some checks
2787
 * on L1 and L2 entries.
2788
 *
2789
 * Returns the number of errors found by the checks or -errno if an internal
2790
 * error occurred.
2791
 */
2792
static int check_refcounts_l1(BlockDriverState *bs,
2793
                              uint16_t *refcount_table,
2794
                              int refcount_table_size,
2795
                              int64_t l1_table_offset, int l1_size,
2796
                              int check_copied)
2797
{
2798
    BDRVQcowState *s = bs->opaque;
2799
    uint64_t *l1_table, l2_offset, l1_size2;
2800
    int i, refcount, ret;
2801
    int errors = 0;
2802

    
2803
    l1_size2 = l1_size * sizeof(uint64_t);
2804

    
2805
    /* Mark L1 table as used */
2806
    errors += inc_refcounts(bs, refcount_table, refcount_table_size,
2807
                  l1_table_offset, l1_size2);
2808

    
2809
    /* Read L1 table entries from disk */
2810
    l1_table = qemu_malloc(l1_size2);
2811
    if (bdrv_pread(s->hd, l1_table_offset,
2812
                   l1_table, l1_size2) != l1_size2)
2813
        goto fail;
2814
    for(i = 0;i < l1_size; i++)
2815
        be64_to_cpus(&l1_table[i]);
2816

    
2817
    /* Do the actual checks */
2818
    for(i = 0; i < l1_size; i++) {
2819
        l2_offset = l1_table[i];
2820
        if (l2_offset) {
2821
            /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
2822
            if (check_copied) {
2823
                refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
2824
                    >> s->cluster_bits);
2825
                if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
2826
                    fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
2827
                        " refcount=%d\n", l2_offset, refcount);
2828
                    errors++;
2829
                }
2830
            }
2831

    
2832
            /* Mark L2 table as used */
2833
            l2_offset &= ~QCOW_OFLAG_COPIED;
2834
            errors += inc_refcounts(bs, refcount_table,
2835
                          refcount_table_size,
2836
                          l2_offset,
2837
                          s->cluster_size);
2838

    
2839
            /* L2 tables are cluster aligned */
2840
            if (l2_offset & (s->cluster_size - 1)) {
2841
                fprintf(stderr, "ERROR l2_offset=%" PRIx64 ": Table is not "
2842
                    "cluster aligned; L1 entry corrupted\n", l2_offset);
2843
                errors++;
2844
            }
2845

    
2846
            /* Process and check L2 entries */
2847
            ret = check_refcounts_l2(bs, refcount_table, refcount_table_size,
2848
                l2_offset, check_copied);
2849
            if (ret < 0) {
2850
                goto fail;
2851
            }
2852
            errors += ret;
2853
        }
2854
    }
2855
    qemu_free(l1_table);
2856
    return errors;
2857

    
2858
fail:
2859
    fprintf(stderr, "ERROR: I/O error in check_refcounts_l1\n");
2860
    qemu_free(l1_table);
2861
    return -EIO;
2862
}
2863

    
2864
/*
2865
 * Checks an image for refcount consistency.
2866
 *
2867
 * Returns 0 if no errors are found, the number of errors in case the image is
2868
 * detected as corrupted, and -errno when an internal error occured.
2869
 */
2870
static int check_refcounts(BlockDriverState *bs)
2871
{
2872
    BDRVQcowState *s = bs->opaque;
2873
    int64_t size;
2874
    int nb_clusters, refcount1, refcount2, i;
2875
    QCowSnapshot *sn;
2876
    uint16_t *refcount_table;
2877
    int ret, errors = 0;
2878

    
2879
    size = bdrv_getlength(s->hd);
2880
    nb_clusters = size_to_clusters(s, size);
2881
    refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
2882

    
2883
    /* header */
2884
    errors += inc_refcounts(bs, refcount_table, nb_clusters,
2885
                  0, s->cluster_size);
2886

    
2887
    /* current L1 table */
2888
    ret = check_refcounts_l1(bs, refcount_table, nb_clusters,
2889
                       s->l1_table_offset, s->l1_size, 1);
2890
    if (ret < 0) {
2891
        return ret;
2892
    }
2893
    errors += ret;
2894

    
2895
    /* snapshots */
2896
    for(i = 0; i < s->nb_snapshots; i++) {
2897
        sn = s->snapshots + i;
2898
        check_refcounts_l1(bs, refcount_table, nb_clusters,
2899
                           sn->l1_table_offset, sn->l1_size, 0);
2900
    }
2901
    errors += inc_refcounts(bs, refcount_table, nb_clusters,
2902
                  s->snapshots_offset, s->snapshots_size);
2903

    
2904
    /* refcount data */
2905
    errors += inc_refcounts(bs, refcount_table, nb_clusters,
2906
                  s->refcount_table_offset,
2907
                  s->refcount_table_size * sizeof(uint64_t));
2908
    for(i = 0; i < s->refcount_table_size; i++) {
2909
        int64_t offset;
2910
        offset = s->refcount_table[i];
2911
        if (offset != 0) {
2912
            errors += inc_refcounts(bs, refcount_table, nb_clusters,
2913
                          offset, s->cluster_size);
2914
        }
2915
    }
2916

    
2917
    /* compare ref counts */
2918
    for(i = 0; i < nb_clusters; i++) {
2919
        refcount1 = get_refcount(bs, i);
2920
        refcount2 = refcount_table[i];
2921
        if (refcount1 != refcount2) {
2922
            fprintf(stderr, "ERROR cluster %d refcount=%d reference=%d\n",
2923
                   i, refcount1, refcount2);
2924
            errors++;
2925
        }
2926
    }
2927

    
2928
    qemu_free(refcount_table);
2929

    
2930
    return errors;
2931
}
2932

    
2933
static int qcow_check(BlockDriverState *bs)
2934
{
2935
    return check_refcounts(bs);
2936
}
2937

    
2938
#if 0
2939
static void dump_refcounts(BlockDriverState *bs)
2940
{
2941
    BDRVQcowState *s = bs->opaque;
2942
    int64_t nb_clusters, k, k1, size;
2943
    int refcount;
2944

2945
    size = bdrv_getlength(s->hd);
2946
    nb_clusters = size_to_clusters(s, size);
2947
    for(k = 0; k < nb_clusters;) {
2948
        k1 = k;
2949
        refcount = get_refcount(bs, k);
2950
        k++;
2951
        while (k < nb_clusters && get_refcount(bs, k) == refcount)
2952
            k++;
2953
        printf("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
2954
    }
2955
}
2956
#endif
2957

    
2958
static int qcow_put_buffer(BlockDriverState *bs, const uint8_t *buf,
2959
                           int64_t pos, int size)
2960
{
2961
    int growable = bs->growable;
2962

    
2963
    bs->growable = 1;
2964
    bdrv_pwrite(bs, pos, buf, size);
2965
    bs->growable = growable;
2966

    
2967
    return size;
2968
}
2969

    
2970
static int qcow_get_buffer(BlockDriverState *bs, uint8_t *buf,
2971
                           int64_t pos, int size)
2972
{
2973
    int growable = bs->growable;
2974
    int ret;
2975

    
2976
    bs->growable = 1;
2977
    ret = bdrv_pread(bs, pos, buf, size);
2978
    bs->growable = growable;
2979

    
2980
    return ret;
2981
}
2982

    
2983
static QEMUOptionParameter qcow_create_options[] = {
2984
    {
2985
        .name = BLOCK_OPT_SIZE,
2986
        .type = OPT_SIZE,
2987
        .help = "Virtual disk size"
2988
    },
2989
    {
2990
        .name = BLOCK_OPT_BACKING_FILE,
2991
        .type = OPT_STRING,
2992
        .help = "File name of a base image"
2993
    },
2994
    {
2995
        .name = BLOCK_OPT_BACKING_FMT,
2996
        .type = OPT_STRING,
2997
        .help = "Image format of the base image"
2998
    },
2999
    {
3000
        .name = BLOCK_OPT_ENCRYPT,
3001
        .type = OPT_FLAG,
3002
        .help = "Encrypt the image"
3003
    },
3004
    {
3005
        .name = BLOCK_OPT_CLUSTER_SIZE,
3006
        .type = OPT_SIZE,
3007
        .help = "qcow2 cluster size"
3008
    },
3009
    { NULL }
3010
};
3011

    
3012
static BlockDriver bdrv_qcow2 = {
3013
    .format_name        = "qcow2",
3014
    .instance_size        = sizeof(BDRVQcowState),
3015
    .bdrv_probe                = qcow_probe,
3016
    .bdrv_open                = qcow_open,
3017
    .bdrv_close                = qcow_close,
3018
    .bdrv_create        = qcow_create,
3019
    .bdrv_flush                = qcow_flush,
3020
    .bdrv_is_allocated        = qcow_is_allocated,
3021
    .bdrv_set_key        = qcow_set_key,
3022
    .bdrv_make_empty        = qcow_make_empty,
3023

    
3024
    .bdrv_aio_readv        = qcow_aio_readv,
3025
    .bdrv_aio_writev        = qcow_aio_writev,
3026
    .bdrv_write_compressed = qcow_write_compressed,
3027

    
3028
    .bdrv_snapshot_create = qcow_snapshot_create,
3029
    .bdrv_snapshot_goto        = qcow_snapshot_goto,
3030
    .bdrv_snapshot_delete = qcow_snapshot_delete,
3031
    .bdrv_snapshot_list        = qcow_snapshot_list,
3032
    .bdrv_get_info        = qcow_get_info,
3033

    
3034
    .bdrv_put_buffer    = qcow_put_buffer,
3035
    .bdrv_get_buffer    = qcow_get_buffer,
3036

    
3037
    .create_options = qcow_create_options,
3038
    .bdrv_check = qcow_check,
3039
};
3040

    
3041
static void bdrv_qcow2_init(void)
3042
{
3043
    bdrv_register(&bdrv_qcow2);
3044
}
3045

    
3046
block_init(bdrv_qcow2_init);