Revision 75411d23

b/Makefile.objs
20 20

  
21 21
block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat.o
22 22
block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
23
block-nested-y += qed.o
23 24
block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o
24 25
block-nested-$(CONFIG_WIN32) += raw-win32.o
25 26
block-nested-$(CONFIG_POSIX) += raw-posix.o
b/block/qed.c
1
/*
2
 * QEMU Enhanced Disk Format
3
 *
4
 * Copyright IBM, Corp. 2010
5
 *
6
 * Authors:
7
 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
8
 *  Anthony Liguori   <aliguori@us.ibm.com>
9
 *
10
 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
11
 * See the COPYING.LIB file in the top-level directory.
12
 *
13
 */
14

  
15
#include "qed.h"
16

  
17
static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
18
                          const char *filename)
19
{
20
    const QEDHeader *header = (const QEDHeader *)buf;
21

  
22
    if (buf_size < sizeof(*header)) {
23
        return 0;
24
    }
25
    if (le32_to_cpu(header->magic) != QED_MAGIC) {
26
        return 0;
27
    }
28
    return 100;
29
}
30

  
31
/**
32
 * Check whether an image format is raw
33
 *
34
 * @fmt:    Backing file format, may be NULL
35
 */
36
static bool qed_fmt_is_raw(const char *fmt)
37
{
38
    return fmt && strcmp(fmt, "raw") == 0;
39
}
40

  
41
static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu)
42
{
43
    cpu->magic = le32_to_cpu(le->magic);
44
    cpu->cluster_size = le32_to_cpu(le->cluster_size);
45
    cpu->table_size = le32_to_cpu(le->table_size);
46
    cpu->header_size = le32_to_cpu(le->header_size);
47
    cpu->features = le64_to_cpu(le->features);
48
    cpu->compat_features = le64_to_cpu(le->compat_features);
49
    cpu->autoclear_features = le64_to_cpu(le->autoclear_features);
50
    cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset);
51
    cpu->image_size = le64_to_cpu(le->image_size);
52
    cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset);
53
    cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size);
54
}
55

  
56
static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le)
57
{
58
    le->magic = cpu_to_le32(cpu->magic);
59
    le->cluster_size = cpu_to_le32(cpu->cluster_size);
60
    le->table_size = cpu_to_le32(cpu->table_size);
61
    le->header_size = cpu_to_le32(cpu->header_size);
62
    le->features = cpu_to_le64(cpu->features);
63
    le->compat_features = cpu_to_le64(cpu->compat_features);
64
    le->autoclear_features = cpu_to_le64(cpu->autoclear_features);
65
    le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset);
66
    le->image_size = cpu_to_le64(cpu->image_size);
67
    le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset);
68
    le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size);
69
}
70

  
71
static int qed_write_header_sync(BDRVQEDState *s)
72
{
73
    QEDHeader le;
74
    int ret;
75

  
76
    qed_header_cpu_to_le(&s->header, &le);
77
    ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le));
78
    if (ret != sizeof(le)) {
79
        return ret;
80
    }
81
    return 0;
82
}
83

  
84
static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size)
85
{
86
    uint64_t table_entries;
87
    uint64_t l2_size;
88

  
89
    table_entries = (table_size * cluster_size) / sizeof(uint64_t);
90
    l2_size = table_entries * cluster_size;
91

  
92
    return l2_size * table_entries;
93
}
94

  
95
static bool qed_is_cluster_size_valid(uint32_t cluster_size)
96
{
97
    if (cluster_size < QED_MIN_CLUSTER_SIZE ||
98
        cluster_size > QED_MAX_CLUSTER_SIZE) {
99
        return false;
100
    }
101
    if (cluster_size & (cluster_size - 1)) {
102
        return false; /* not power of 2 */
103
    }
104
    return true;
105
}
106

  
107
static bool qed_is_table_size_valid(uint32_t table_size)
108
{
109
    if (table_size < QED_MIN_TABLE_SIZE ||
110
        table_size > QED_MAX_TABLE_SIZE) {
111
        return false;
112
    }
113
    if (table_size & (table_size - 1)) {
114
        return false; /* not power of 2 */
115
    }
116
    return true;
117
}
118

  
119
static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size,
120
                                    uint32_t table_size)
121
{
122
    if (image_size % BDRV_SECTOR_SIZE != 0) {
123
        return false; /* not multiple of sector size */
124
    }
125
    if (image_size > qed_max_image_size(cluster_size, table_size)) {
126
        return false; /* image is too large */
127
    }
128
    return true;
129
}
130

  
131
/**
132
 * Read a string of known length from the image file
133
 *
134
 * @file:       Image file
135
 * @offset:     File offset to start of string, in bytes
136
 * @n:          String length in bytes
137
 * @buf:        Destination buffer
138
 * @buflen:     Destination buffer length in bytes
139
 * @ret:        0 on success, -errno on failure
140
 *
141
 * The string is NUL-terminated.
142
 */
143
static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
144
                           char *buf, size_t buflen)
145
{
146
    int ret;
147
    if (n >= buflen) {
148
        return -EINVAL;
149
    }
150
    ret = bdrv_pread(file, offset, buf, n);
151
    if (ret < 0) {
152
        return ret;
153
    }
154
    buf[n] = '\0';
155
    return 0;
156
}
157

  
158
static int bdrv_qed_open(BlockDriverState *bs, int flags)
159
{
160
    BDRVQEDState *s = bs->opaque;
161
    QEDHeader le_header;
162
    int64_t file_size;
163
    int ret;
164

  
165
    s->bs = bs;
166

  
167
    ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
168
    if (ret < 0) {
169
        return ret;
170
    }
171
    ret = 0; /* ret should always be 0 or -errno */
172
    qed_header_le_to_cpu(&le_header, &s->header);
173

  
174
    if (s->header.magic != QED_MAGIC) {
175
        return -EINVAL;
176
    }
177
    if (s->header.features & ~QED_FEATURE_MASK) {
178
        return -ENOTSUP; /* image uses unsupported feature bits */
179
    }
180
    if (!qed_is_cluster_size_valid(s->header.cluster_size)) {
181
        return -EINVAL;
182
    }
183

  
184
    /* Round down file size to the last cluster */
185
    file_size = bdrv_getlength(bs->file);
186
    if (file_size < 0) {
187
        return file_size;
188
    }
189
    s->file_size = qed_start_of_cluster(s, file_size);
190

  
191
    if (!qed_is_table_size_valid(s->header.table_size)) {
192
        return -EINVAL;
193
    }
194
    if (!qed_is_image_size_valid(s->header.image_size,
195
                                 s->header.cluster_size,
196
                                 s->header.table_size)) {
197
        return -EINVAL;
198
    }
199
    if (!qed_check_table_offset(s, s->header.l1_table_offset)) {
200
        return -EINVAL;
201
    }
202

  
203
    s->table_nelems = (s->header.cluster_size * s->header.table_size) /
204
                      sizeof(uint64_t);
205
    s->l2_shift = ffs(s->header.cluster_size) - 1;
206
    s->l2_mask = s->table_nelems - 1;
207
    s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1;
208

  
209
    if ((s->header.features & QED_F_BACKING_FILE)) {
210
        if ((uint64_t)s->header.backing_filename_offset +
211
            s->header.backing_filename_size >
212
            s->header.cluster_size * s->header.header_size) {
213
            return -EINVAL;
214
        }
215

  
216
        ret = qed_read_string(bs->file, s->header.backing_filename_offset,
217
                              s->header.backing_filename_size, bs->backing_file,
218
                              sizeof(bs->backing_file));
219
        if (ret < 0) {
220
            return ret;
221
        }
222

  
223
        if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) {
224
            pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw");
225
        }
226
    }
227

  
228
    /* Reset unknown autoclear feature bits.  This is a backwards
229
     * compatibility mechanism that allows images to be opened by older
230
     * programs, which "knock out" unknown feature bits.  When an image is
231
     * opened by a newer program again it can detect that the autoclear
232
     * feature is no longer valid.
233
     */
234
    if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 &&
235
        !bdrv_is_read_only(bs->file)) {
236
        s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK;
237

  
238
        ret = qed_write_header_sync(s);
239
        if (ret) {
240
            return ret;
241
        }
242

  
243
        /* From here on only known autoclear feature bits are valid */
244
        bdrv_flush(bs->file);
245
    }
246

  
247
    return ret;
248
}
249

  
250
static void bdrv_qed_close(BlockDriverState *bs)
251
{
252
}
253

  
254
static int bdrv_qed_flush(BlockDriverState *bs)
255
{
256
    return bdrv_flush(bs->file);
257
}
258

  
259
static int qed_create(const char *filename, uint32_t cluster_size,
260
                      uint64_t image_size, uint32_t table_size,
261
                      const char *backing_file, const char *backing_fmt)
262
{
263
    QEDHeader header = {
264
        .magic = QED_MAGIC,
265
        .cluster_size = cluster_size,
266
        .table_size = table_size,
267
        .header_size = 1,
268
        .features = 0,
269
        .compat_features = 0,
270
        .l1_table_offset = cluster_size,
271
        .image_size = image_size,
272
    };
273
    QEDHeader le_header;
274
    uint8_t *l1_table = NULL;
275
    size_t l1_size = header.cluster_size * header.table_size;
276
    int ret = 0;
277
    BlockDriverState *bs = NULL;
278

  
279
    ret = bdrv_create_file(filename, NULL);
280
    if (ret < 0) {
281
        return ret;
282
    }
283

  
284
    ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR | BDRV_O_CACHE_WB);
285
    if (ret < 0) {
286
        return ret;
287
    }
288

  
289
    if (backing_file) {
290
        header.features |= QED_F_BACKING_FILE;
291
        header.backing_filename_offset = sizeof(le_header);
292
        header.backing_filename_size = strlen(backing_file);
293

  
294
        if (qed_fmt_is_raw(backing_fmt)) {
295
            header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
296
        }
297
    }
298

  
299
    qed_header_cpu_to_le(&header, &le_header);
300
    ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header));
301
    if (ret < 0) {
302
        goto out;
303
    }
304
    ret = bdrv_pwrite(bs, sizeof(le_header), backing_file,
305
                      header.backing_filename_size);
306
    if (ret < 0) {
307
        goto out;
308
    }
309

  
310
    l1_table = qemu_mallocz(l1_size);
311
    ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size);
312
    if (ret < 0) {
313
        goto out;
314
    }
315

  
316
    ret = 0; /* success */
317
out:
318
    qemu_free(l1_table);
319
    bdrv_delete(bs);
320
    return ret;
321
}
322

  
323
static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options)
324
{
325
    uint64_t image_size = 0;
326
    uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE;
327
    uint32_t table_size = QED_DEFAULT_TABLE_SIZE;
328
    const char *backing_file = NULL;
329
    const char *backing_fmt = NULL;
330

  
331
    while (options && options->name) {
332
        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
333
            image_size = options->value.n;
334
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
335
            backing_file = options->value.s;
336
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
337
            backing_fmt = options->value.s;
338
        } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
339
            if (options->value.n) {
340
                cluster_size = options->value.n;
341
            }
342
        } else if (!strcmp(options->name, BLOCK_OPT_TABLE_SIZE)) {
343
            if (options->value.n) {
344
                table_size = options->value.n;
345
            }
346
        }
347
        options++;
348
    }
349

  
350
    if (!qed_is_cluster_size_valid(cluster_size)) {
351
        fprintf(stderr, "QED cluster size must be within range [%u, %u] and power of 2\n",
352
                QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE);
353
        return -EINVAL;
354
    }
355
    if (!qed_is_table_size_valid(table_size)) {
356
        fprintf(stderr, "QED table size must be within range [%u, %u] and power of 2\n",
357
                QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE);
358
        return -EINVAL;
359
    }
360
    if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) {
361
        fprintf(stderr, "QED image size must be a non-zero multiple of "
362
                        "cluster size and less than %" PRIu64 " bytes\n",
363
                qed_max_image_size(cluster_size, table_size));
364
        return -EINVAL;
365
    }
366

  
367
    return qed_create(filename, cluster_size, image_size, table_size,
368
                      backing_file, backing_fmt);
369
}
370

  
371
static int bdrv_qed_is_allocated(BlockDriverState *bs, int64_t sector_num,
372
                                  int nb_sectors, int *pnum)
373
{
374
    return -ENOTSUP;
375
}
376

  
377
static int bdrv_qed_make_empty(BlockDriverState *bs)
378
{
379
    return -ENOTSUP;
380
}
381

  
382
static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs,
383
                                            int64_t sector_num,
384
                                            QEMUIOVector *qiov, int nb_sectors,
385
                                            BlockDriverCompletionFunc *cb,
386
                                            void *opaque)
387
{
388
    return NULL;
389
}
390

  
391
static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs,
392
                                             int64_t sector_num,
393
                                             QEMUIOVector *qiov, int nb_sectors,
394
                                             BlockDriverCompletionFunc *cb,
395
                                             void *opaque)
396
{
397
    return NULL;
398
}
399

  
400
static BlockDriverAIOCB *bdrv_qed_aio_flush(BlockDriverState *bs,
401
                                            BlockDriverCompletionFunc *cb,
402
                                            void *opaque)
403
{
404
    return bdrv_aio_flush(bs->file, cb, opaque);
405
}
406

  
407
static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
408
{
409
    return -ENOTSUP;
410
}
411

  
412
static int64_t bdrv_qed_getlength(BlockDriverState *bs)
413
{
414
    BDRVQEDState *s = bs->opaque;
415
    return s->header.image_size;
416
}
417

  
418
static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
419
{
420
    BDRVQEDState *s = bs->opaque;
421

  
422
    memset(bdi, 0, sizeof(*bdi));
423
    bdi->cluster_size = s->header.cluster_size;
424
    return 0;
425
}
426

  
427
static int bdrv_qed_change_backing_file(BlockDriverState *bs,
428
                                        const char *backing_file,
429
                                        const char *backing_fmt)
430
{
431
    BDRVQEDState *s = bs->opaque;
432
    QEDHeader new_header, le_header;
433
    void *buffer;
434
    size_t buffer_len, backing_file_len;
435
    int ret;
436

  
437
    /* Refuse to set backing filename if unknown compat feature bits are
438
     * active.  If the image uses an unknown compat feature then we may not
439
     * know the layout of data following the header structure and cannot safely
440
     * add a new string.
441
     */
442
    if (backing_file && (s->header.compat_features &
443
                         ~QED_COMPAT_FEATURE_MASK)) {
444
        return -ENOTSUP;
445
    }
446

  
447
    memcpy(&new_header, &s->header, sizeof(new_header));
448

  
449
    new_header.features &= ~(QED_F_BACKING_FILE |
450
                             QED_F_BACKING_FORMAT_NO_PROBE);
451

  
452
    /* Adjust feature flags */
453
    if (backing_file) {
454
        new_header.features |= QED_F_BACKING_FILE;
455

  
456
        if (qed_fmt_is_raw(backing_fmt)) {
457
            new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
458
        }
459
    }
460

  
461
    /* Calculate new header size */
462
    backing_file_len = 0;
463

  
464
    if (backing_file) {
465
        backing_file_len = strlen(backing_file);
466
    }
467

  
468
    buffer_len = sizeof(new_header);
469
    new_header.backing_filename_offset = buffer_len;
470
    new_header.backing_filename_size = backing_file_len;
471
    buffer_len += backing_file_len;
472

  
473
    /* Make sure we can rewrite header without failing */
474
    if (buffer_len > new_header.header_size * new_header.cluster_size) {
475
        return -ENOSPC;
476
    }
477

  
478
    /* Prepare new header */
479
    buffer = qemu_malloc(buffer_len);
480

  
481
    qed_header_cpu_to_le(&new_header, &le_header);
482
    memcpy(buffer, &le_header, sizeof(le_header));
483
    buffer_len = sizeof(le_header);
484

  
485
    memcpy(buffer + buffer_len, backing_file, backing_file_len);
486
    buffer_len += backing_file_len;
487

  
488
    /* Write new header */
489
    ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
490
    qemu_free(buffer);
491
    if (ret == 0) {
492
        memcpy(&s->header, &new_header, sizeof(new_header));
493
    }
494
    return ret;
495
}
496

  
497
static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result)
498
{
499
    return -ENOTSUP;
500
}
501

  
502
static QEMUOptionParameter qed_create_options[] = {
503
    {
504
        .name = BLOCK_OPT_SIZE,
505
        .type = OPT_SIZE,
506
        .help = "Virtual disk size (in bytes)"
507
    }, {
508
        .name = BLOCK_OPT_BACKING_FILE,
509
        .type = OPT_STRING,
510
        .help = "File name of a base image"
511
    }, {
512
        .name = BLOCK_OPT_BACKING_FMT,
513
        .type = OPT_STRING,
514
        .help = "Image format of the base image"
515
    }, {
516
        .name = BLOCK_OPT_CLUSTER_SIZE,
517
        .type = OPT_SIZE,
518
        .help = "Cluster size (in bytes)"
519
    }, {
520
        .name = BLOCK_OPT_TABLE_SIZE,
521
        .type = OPT_SIZE,
522
        .help = "L1/L2 table size (in clusters)"
523
    },
524
    { /* end of list */ }
525
};
526

  
527
static BlockDriver bdrv_qed = {
528
    .format_name              = "qed",
529
    .instance_size            = sizeof(BDRVQEDState),
530
    .create_options           = qed_create_options,
531

  
532
    .bdrv_probe               = bdrv_qed_probe,
533
    .bdrv_open                = bdrv_qed_open,
534
    .bdrv_close               = bdrv_qed_close,
535
    .bdrv_create              = bdrv_qed_create,
536
    .bdrv_flush               = bdrv_qed_flush,
537
    .bdrv_is_allocated        = bdrv_qed_is_allocated,
538
    .bdrv_make_empty          = bdrv_qed_make_empty,
539
    .bdrv_aio_readv           = bdrv_qed_aio_readv,
540
    .bdrv_aio_writev          = bdrv_qed_aio_writev,
541
    .bdrv_aio_flush           = bdrv_qed_aio_flush,
542
    .bdrv_truncate            = bdrv_qed_truncate,
543
    .bdrv_getlength           = bdrv_qed_getlength,
544
    .bdrv_get_info            = bdrv_qed_get_info,
545
    .bdrv_change_backing_file = bdrv_qed_change_backing_file,
546
    .bdrv_check               = bdrv_qed_check,
547
};
548

  
549
static void bdrv_qed_init(void)
550
{
551
    bdrv_register(&bdrv_qed);
552
}
553

  
554
block_init(bdrv_qed_init);
b/block/qed.h
1
/*
2
 * QEMU Enhanced Disk Format
3
 *
4
 * Copyright IBM, Corp. 2010
5
 *
6
 * Authors:
7
 *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
8
 *  Anthony Liguori   <aliguori@us.ibm.com>
9
 *
10
 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
11
 * See the COPYING.LIB file in the top-level directory.
12
 *
13
 */
14

  
15
#ifndef BLOCK_QED_H
16
#define BLOCK_QED_H
17

  
18
#include "block_int.h"
19

  
20
/* The layout of a QED file is as follows:
21
 *
22
 * +--------+----------+----------+----------+-----+
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 * | header | L1 table | cluster0 | cluster1 | ... |
24
 * +--------+----------+----------+----------+-----+
25
 *
26
 * There is a 2-level pagetable for cluster allocation:
27
 *
28
 *                     +----------+
29
 *                     | L1 table |
30
 *                     +----------+
31
 *                ,------'  |  '------.
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 *           +----------+   |    +----------+
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 *           | L2 table |  ...   | L2 table |
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 *           +----------+        +----------+
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 *       ,------'  |  '------.
36
 *  +----------+   |    +----------+
37
 *  |   Data   |  ...   |   Data   |
38
 *  +----------+        +----------+
39
 *
40
 * The L1 table is fixed size and always present.  L2 tables are allocated on
41
 * demand.  The L1 table size determines the maximum possible image size; it
42
 * can be influenced using the cluster_size and table_size values.
43
 *
44
 * All fields are little-endian on disk.
45
 */
46

  
47
enum {
48
    QED_MAGIC = 'Q' | 'E' << 8 | 'D' << 16 | '\0' << 24,
49

  
50
    /* The image supports a backing file */
51
    QED_F_BACKING_FILE = 0x01,
52

  
53
    /* The backing file format must not be probed, treat as raw image */
54
    QED_F_BACKING_FORMAT_NO_PROBE = 0x04,
55

  
56
    /* Feature bits must be used when the on-disk format changes */
57
    QED_FEATURE_MASK = QED_F_BACKING_FILE | /* supported feature bits */
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                       QED_F_BACKING_FORMAT_NO_PROBE,
59
    QED_COMPAT_FEATURE_MASK = 0,            /* supported compat feature bits */
60
    QED_AUTOCLEAR_FEATURE_MASK = 0,         /* supported autoclear feature bits */
61

  
62
    /* Data is stored in groups of sectors called clusters.  Cluster size must
63
     * be large to avoid keeping too much metadata.  I/O requests that have
64
     * sub-cluster size will require read-modify-write.
65
     */
66
    QED_MIN_CLUSTER_SIZE = 4 * 1024, /* in bytes */
67
    QED_MAX_CLUSTER_SIZE = 64 * 1024 * 1024,
68
    QED_DEFAULT_CLUSTER_SIZE = 64 * 1024,
69

  
70
    /* Allocated clusters are tracked using a 2-level pagetable.  Table size is
71
     * a multiple of clusters so large maximum image sizes can be supported
72
     * without jacking up the cluster size too much.
73
     */
74
    QED_MIN_TABLE_SIZE = 1,        /* in clusters */
75
    QED_MAX_TABLE_SIZE = 16,
76
    QED_DEFAULT_TABLE_SIZE = 4,
77
};
78

  
79
typedef struct {
80
    uint32_t magic;                 /* QED\0 */
81

  
82
    uint32_t cluster_size;          /* in bytes */
83
    uint32_t table_size;            /* for L1 and L2 tables, in clusters */
84
    uint32_t header_size;           /* in clusters */
85

  
86
    uint64_t features;              /* format feature bits */
87
    uint64_t compat_features;       /* compatible feature bits */
88
    uint64_t autoclear_features;    /* self-resetting feature bits */
89

  
90
    uint64_t l1_table_offset;       /* in bytes */
91
    uint64_t image_size;            /* total logical image size, in bytes */
92

  
93
    /* if (features & QED_F_BACKING_FILE) */
94
    uint32_t backing_filename_offset; /* in bytes from start of header */
95
    uint32_t backing_filename_size;   /* in bytes */
96
} QEDHeader;
97

  
98
typedef struct {
99
    BlockDriverState *bs;           /* device */
100
    uint64_t file_size;             /* length of image file, in bytes */
101

  
102
    QEDHeader header;               /* always cpu-endian */
103
    uint32_t table_nelems;
104
    uint32_t l1_shift;
105
    uint32_t l2_shift;
106
    uint32_t l2_mask;
107
} BDRVQEDState;
108

  
109
/**
110
 * Round down to the start of a cluster
111
 */
112
static inline uint64_t qed_start_of_cluster(BDRVQEDState *s, uint64_t offset)
113
{
114
    return offset & ~(uint64_t)(s->header.cluster_size - 1);
115
}
116

  
117
/**
118
 * Test if a cluster offset is valid
119
 */
120
static inline bool qed_check_cluster_offset(BDRVQEDState *s, uint64_t offset)
121
{
122
    uint64_t header_size = (uint64_t)s->header.header_size *
123
                           s->header.cluster_size;
124

  
125
    if (offset & (s->header.cluster_size - 1)) {
126
        return false;
127
    }
128
    return offset >= header_size && offset < s->file_size;
129
}
130

  
131
/**
132
 * Test if a table offset is valid
133
 */
134
static inline bool qed_check_table_offset(BDRVQEDState *s, uint64_t offset)
135
{
136
    uint64_t end_offset = offset + (s->header.table_size - 1) *
137
                          s->header.cluster_size;
138

  
139
    /* Overflow check */
140
    if (end_offset <= offset) {
141
        return false;
142
    }
143

  
144
    return qed_check_cluster_offset(s, offset) &&
145
           qed_check_cluster_offset(s, end_offset);
146
}
147

  
148
#endif /* BLOCK_QED_H */
b/block_int.h
37 37
#define BLOCK_OPT_BACKING_FILE  "backing_file"
38 38
#define BLOCK_OPT_BACKING_FMT   "backing_fmt"
39 39
#define BLOCK_OPT_CLUSTER_SIZE  "cluster_size"
40
#define BLOCK_OPT_TABLE_SIZE    "table_size"
40 41
#define BLOCK_OPT_PREALLOC      "preallocation"
41 42

  
42 43
typedef struct AIOPool {

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