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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 "qemu-timer.h"
16
#include "trace.h"
17
#include "qed.h"
18
#include "qerror.h"
19
#include "migration.h"
20

    
21
static void qed_aio_cancel(BlockDriverAIOCB *blockacb)
22
{
23
    QEDAIOCB *acb = (QEDAIOCB *)blockacb;
24
    bool finished = false;
25

    
26
    /* Wait for the request to finish */
27
    acb->finished = &finished;
28
    while (!finished) {
29
        qemu_aio_wait();
30
    }
31
}
32

    
33
static AIOPool qed_aio_pool = {
34
    .aiocb_size         = sizeof(QEDAIOCB),
35
    .cancel             = qed_aio_cancel,
36
};
37

    
38
static int bdrv_qed_probe(const uint8_t *buf, int buf_size,
39
                          const char *filename)
40
{
41
    const QEDHeader *header = (const QEDHeader *)buf;
42

    
43
    if (buf_size < sizeof(*header)) {
44
        return 0;
45
    }
46
    if (le32_to_cpu(header->magic) != QED_MAGIC) {
47
        return 0;
48
    }
49
    return 100;
50
}
51

    
52
/**
53
 * Check whether an image format is raw
54
 *
55
 * @fmt:    Backing file format, may be NULL
56
 */
57
static bool qed_fmt_is_raw(const char *fmt)
58
{
59
    return fmt && strcmp(fmt, "raw") == 0;
60
}
61

    
62
static void qed_header_le_to_cpu(const QEDHeader *le, QEDHeader *cpu)
63
{
64
    cpu->magic = le32_to_cpu(le->magic);
65
    cpu->cluster_size = le32_to_cpu(le->cluster_size);
66
    cpu->table_size = le32_to_cpu(le->table_size);
67
    cpu->header_size = le32_to_cpu(le->header_size);
68
    cpu->features = le64_to_cpu(le->features);
69
    cpu->compat_features = le64_to_cpu(le->compat_features);
70
    cpu->autoclear_features = le64_to_cpu(le->autoclear_features);
71
    cpu->l1_table_offset = le64_to_cpu(le->l1_table_offset);
72
    cpu->image_size = le64_to_cpu(le->image_size);
73
    cpu->backing_filename_offset = le32_to_cpu(le->backing_filename_offset);
74
    cpu->backing_filename_size = le32_to_cpu(le->backing_filename_size);
75
}
76

    
77
static void qed_header_cpu_to_le(const QEDHeader *cpu, QEDHeader *le)
78
{
79
    le->magic = cpu_to_le32(cpu->magic);
80
    le->cluster_size = cpu_to_le32(cpu->cluster_size);
81
    le->table_size = cpu_to_le32(cpu->table_size);
82
    le->header_size = cpu_to_le32(cpu->header_size);
83
    le->features = cpu_to_le64(cpu->features);
84
    le->compat_features = cpu_to_le64(cpu->compat_features);
85
    le->autoclear_features = cpu_to_le64(cpu->autoclear_features);
86
    le->l1_table_offset = cpu_to_le64(cpu->l1_table_offset);
87
    le->image_size = cpu_to_le64(cpu->image_size);
88
    le->backing_filename_offset = cpu_to_le32(cpu->backing_filename_offset);
89
    le->backing_filename_size = cpu_to_le32(cpu->backing_filename_size);
90
}
91

    
92
int qed_write_header_sync(BDRVQEDState *s)
93
{
94
    QEDHeader le;
95
    int ret;
96

    
97
    qed_header_cpu_to_le(&s->header, &le);
98
    ret = bdrv_pwrite(s->bs->file, 0, &le, sizeof(le));
99
    if (ret != sizeof(le)) {
100
        return ret;
101
    }
102
    return 0;
103
}
104

    
105
typedef struct {
106
    GenericCB gencb;
107
    BDRVQEDState *s;
108
    struct iovec iov;
109
    QEMUIOVector qiov;
110
    int nsectors;
111
    uint8_t *buf;
112
} QEDWriteHeaderCB;
113

    
114
static void qed_write_header_cb(void *opaque, int ret)
115
{
116
    QEDWriteHeaderCB *write_header_cb = opaque;
117

    
118
    qemu_vfree(write_header_cb->buf);
119
    gencb_complete(write_header_cb, ret);
120
}
121

    
122
static void qed_write_header_read_cb(void *opaque, int ret)
123
{
124
    QEDWriteHeaderCB *write_header_cb = opaque;
125
    BDRVQEDState *s = write_header_cb->s;
126

    
127
    if (ret) {
128
        qed_write_header_cb(write_header_cb, ret);
129
        return;
130
    }
131

    
132
    /* Update header */
133
    qed_header_cpu_to_le(&s->header, (QEDHeader *)write_header_cb->buf);
134

    
135
    bdrv_aio_writev(s->bs->file, 0, &write_header_cb->qiov,
136
                    write_header_cb->nsectors, qed_write_header_cb,
137
                    write_header_cb);
138
}
139

    
140
/**
141
 * Update header in-place (does not rewrite backing filename or other strings)
142
 *
143
 * This function only updates known header fields in-place and does not affect
144
 * extra data after the QED header.
145
 */
146
static void qed_write_header(BDRVQEDState *s, BlockDriverCompletionFunc cb,
147
                             void *opaque)
148
{
149
    /* We must write full sectors for O_DIRECT but cannot necessarily generate
150
     * the data following the header if an unrecognized compat feature is
151
     * active.  Therefore, first read the sectors containing the header, update
152
     * them, and write back.
153
     */
154

    
155
    int nsectors = (sizeof(QEDHeader) + BDRV_SECTOR_SIZE - 1) /
156
                   BDRV_SECTOR_SIZE;
157
    size_t len = nsectors * BDRV_SECTOR_SIZE;
158
    QEDWriteHeaderCB *write_header_cb = gencb_alloc(sizeof(*write_header_cb),
159
                                                    cb, opaque);
160

    
161
    write_header_cb->s = s;
162
    write_header_cb->nsectors = nsectors;
163
    write_header_cb->buf = qemu_blockalign(s->bs, len);
164
    write_header_cb->iov.iov_base = write_header_cb->buf;
165
    write_header_cb->iov.iov_len = len;
166
    qemu_iovec_init_external(&write_header_cb->qiov, &write_header_cb->iov, 1);
167

    
168
    bdrv_aio_readv(s->bs->file, 0, &write_header_cb->qiov, nsectors,
169
                   qed_write_header_read_cb, write_header_cb);
170
}
171

    
172
static uint64_t qed_max_image_size(uint32_t cluster_size, uint32_t table_size)
173
{
174
    uint64_t table_entries;
175
    uint64_t l2_size;
176

    
177
    table_entries = (table_size * cluster_size) / sizeof(uint64_t);
178
    l2_size = table_entries * cluster_size;
179

    
180
    return l2_size * table_entries;
181
}
182

    
183
static bool qed_is_cluster_size_valid(uint32_t cluster_size)
184
{
185
    if (cluster_size < QED_MIN_CLUSTER_SIZE ||
186
        cluster_size > QED_MAX_CLUSTER_SIZE) {
187
        return false;
188
    }
189
    if (cluster_size & (cluster_size - 1)) {
190
        return false; /* not power of 2 */
191
    }
192
    return true;
193
}
194

    
195
static bool qed_is_table_size_valid(uint32_t table_size)
196
{
197
    if (table_size < QED_MIN_TABLE_SIZE ||
198
        table_size > QED_MAX_TABLE_SIZE) {
199
        return false;
200
    }
201
    if (table_size & (table_size - 1)) {
202
        return false; /* not power of 2 */
203
    }
204
    return true;
205
}
206

    
207
static bool qed_is_image_size_valid(uint64_t image_size, uint32_t cluster_size,
208
                                    uint32_t table_size)
209
{
210
    if (image_size % BDRV_SECTOR_SIZE != 0) {
211
        return false; /* not multiple of sector size */
212
    }
213
    if (image_size > qed_max_image_size(cluster_size, table_size)) {
214
        return false; /* image is too large */
215
    }
216
    return true;
217
}
218

    
219
/**
220
 * Read a string of known length from the image file
221
 *
222
 * @file:       Image file
223
 * @offset:     File offset to start of string, in bytes
224
 * @n:          String length in bytes
225
 * @buf:        Destination buffer
226
 * @buflen:     Destination buffer length in bytes
227
 * @ret:        0 on success, -errno on failure
228
 *
229
 * The string is NUL-terminated.
230
 */
231
static int qed_read_string(BlockDriverState *file, uint64_t offset, size_t n,
232
                           char *buf, size_t buflen)
233
{
234
    int ret;
235
    if (n >= buflen) {
236
        return -EINVAL;
237
    }
238
    ret = bdrv_pread(file, offset, buf, n);
239
    if (ret < 0) {
240
        return ret;
241
    }
242
    buf[n] = '\0';
243
    return 0;
244
}
245

    
246
/**
247
 * Allocate new clusters
248
 *
249
 * @s:          QED state
250
 * @n:          Number of contiguous clusters to allocate
251
 * @ret:        Offset of first allocated cluster
252
 *
253
 * This function only produces the offset where the new clusters should be
254
 * written.  It updates BDRVQEDState but does not make any changes to the image
255
 * file.
256
 */
257
static uint64_t qed_alloc_clusters(BDRVQEDState *s, unsigned int n)
258
{
259
    uint64_t offset = s->file_size;
260
    s->file_size += n * s->header.cluster_size;
261
    return offset;
262
}
263

    
264
QEDTable *qed_alloc_table(BDRVQEDState *s)
265
{
266
    /* Honor O_DIRECT memory alignment requirements */
267
    return qemu_blockalign(s->bs,
268
                           s->header.cluster_size * s->header.table_size);
269
}
270

    
271
/**
272
 * Allocate a new zeroed L2 table
273
 */
274
static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
275
{
276
    CachedL2Table *l2_table = qed_alloc_l2_cache_entry(&s->l2_cache);
277

    
278
    l2_table->table = qed_alloc_table(s);
279
    l2_table->offset = qed_alloc_clusters(s, s->header.table_size);
280

    
281
    memset(l2_table->table->offsets, 0,
282
           s->header.cluster_size * s->header.table_size);
283
    return l2_table;
284
}
285

    
286
static void qed_aio_next_io(void *opaque, int ret);
287

    
288
static void qed_plug_allocating_write_reqs(BDRVQEDState *s)
289
{
290
    assert(!s->allocating_write_reqs_plugged);
291

    
292
    s->allocating_write_reqs_plugged = true;
293
}
294

    
295
static void qed_unplug_allocating_write_reqs(BDRVQEDState *s)
296
{
297
    QEDAIOCB *acb;
298

    
299
    assert(s->allocating_write_reqs_plugged);
300

    
301
    s->allocating_write_reqs_plugged = false;
302

    
303
    acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
304
    if (acb) {
305
        qed_aio_next_io(acb, 0);
306
    }
307
}
308

    
309
static void qed_finish_clear_need_check(void *opaque, int ret)
310
{
311
    /* Do nothing */
312
}
313

    
314
static void qed_flush_after_clear_need_check(void *opaque, int ret)
315
{
316
    BDRVQEDState *s = opaque;
317

    
318
    bdrv_aio_flush(s->bs, qed_finish_clear_need_check, s);
319

    
320
    /* No need to wait until flush completes */
321
    qed_unplug_allocating_write_reqs(s);
322
}
323

    
324
static void qed_clear_need_check(void *opaque, int ret)
325
{
326
    BDRVQEDState *s = opaque;
327

    
328
    if (ret) {
329
        qed_unplug_allocating_write_reqs(s);
330
        return;
331
    }
332

    
333
    s->header.features &= ~QED_F_NEED_CHECK;
334
    qed_write_header(s, qed_flush_after_clear_need_check, s);
335
}
336

    
337
static void qed_need_check_timer_cb(void *opaque)
338
{
339
    BDRVQEDState *s = opaque;
340

    
341
    /* The timer should only fire when allocating writes have drained */
342
    assert(!QSIMPLEQ_FIRST(&s->allocating_write_reqs));
343

    
344
    trace_qed_need_check_timer_cb(s);
345

    
346
    qed_plug_allocating_write_reqs(s);
347

    
348
    /* Ensure writes are on disk before clearing flag */
349
    bdrv_aio_flush(s->bs, qed_clear_need_check, s);
350
}
351

    
352
static void qed_start_need_check_timer(BDRVQEDState *s)
353
{
354
    trace_qed_start_need_check_timer(s);
355

    
356
    /* Use vm_clock so we don't alter the image file while suspended for
357
     * migration.
358
     */
359
    qemu_mod_timer(s->need_check_timer, qemu_get_clock_ns(vm_clock) +
360
                   get_ticks_per_sec() * QED_NEED_CHECK_TIMEOUT);
361
}
362

    
363
/* It's okay to call this multiple times or when no timer is started */
364
static void qed_cancel_need_check_timer(BDRVQEDState *s)
365
{
366
    trace_qed_cancel_need_check_timer(s);
367
    qemu_del_timer(s->need_check_timer);
368
}
369

    
370
static void bdrv_qed_rebind(BlockDriverState *bs)
371
{
372
    BDRVQEDState *s = bs->opaque;
373
    s->bs = bs;
374
}
375

    
376
static int bdrv_qed_open(BlockDriverState *bs, int flags)
377
{
378
    BDRVQEDState *s = bs->opaque;
379
    QEDHeader le_header;
380
    int64_t file_size;
381
    int ret;
382

    
383
    s->bs = bs;
384
    QSIMPLEQ_INIT(&s->allocating_write_reqs);
385

    
386
    ret = bdrv_pread(bs->file, 0, &le_header, sizeof(le_header));
387
    if (ret < 0) {
388
        return ret;
389
    }
390
    qed_header_le_to_cpu(&le_header, &s->header);
391

    
392
    if (s->header.magic != QED_MAGIC) {
393
        return -EINVAL;
394
    }
395
    if (s->header.features & ~QED_FEATURE_MASK) {
396
        /* image uses unsupported feature bits */
397
        char buf[64];
398
        snprintf(buf, sizeof(buf), "%" PRIx64,
399
            s->header.features & ~QED_FEATURE_MASK);
400
        qerror_report(QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
401
            bs->device_name, "QED", buf);
402
        return -ENOTSUP;
403
    }
404
    if (!qed_is_cluster_size_valid(s->header.cluster_size)) {
405
        return -EINVAL;
406
    }
407

    
408
    /* Round down file size to the last cluster */
409
    file_size = bdrv_getlength(bs->file);
410
    if (file_size < 0) {
411
        return file_size;
412
    }
413
    s->file_size = qed_start_of_cluster(s, file_size);
414

    
415
    if (!qed_is_table_size_valid(s->header.table_size)) {
416
        return -EINVAL;
417
    }
418
    if (!qed_is_image_size_valid(s->header.image_size,
419
                                 s->header.cluster_size,
420
                                 s->header.table_size)) {
421
        return -EINVAL;
422
    }
423
    if (!qed_check_table_offset(s, s->header.l1_table_offset)) {
424
        return -EINVAL;
425
    }
426

    
427
    s->table_nelems = (s->header.cluster_size * s->header.table_size) /
428
                      sizeof(uint64_t);
429
    s->l2_shift = ffs(s->header.cluster_size) - 1;
430
    s->l2_mask = s->table_nelems - 1;
431
    s->l1_shift = s->l2_shift + ffs(s->table_nelems) - 1;
432

    
433
    if ((s->header.features & QED_F_BACKING_FILE)) {
434
        if ((uint64_t)s->header.backing_filename_offset +
435
            s->header.backing_filename_size >
436
            s->header.cluster_size * s->header.header_size) {
437
            return -EINVAL;
438
        }
439

    
440
        ret = qed_read_string(bs->file, s->header.backing_filename_offset,
441
                              s->header.backing_filename_size, bs->backing_file,
442
                              sizeof(bs->backing_file));
443
        if (ret < 0) {
444
            return ret;
445
        }
446

    
447
        if (s->header.features & QED_F_BACKING_FORMAT_NO_PROBE) {
448
            pstrcpy(bs->backing_format, sizeof(bs->backing_format), "raw");
449
        }
450
    }
451

    
452
    /* Reset unknown autoclear feature bits.  This is a backwards
453
     * compatibility mechanism that allows images to be opened by older
454
     * programs, which "knock out" unknown feature bits.  When an image is
455
     * opened by a newer program again it can detect that the autoclear
456
     * feature is no longer valid.
457
     */
458
    if ((s->header.autoclear_features & ~QED_AUTOCLEAR_FEATURE_MASK) != 0 &&
459
        !bdrv_is_read_only(bs->file) && !(flags & BDRV_O_INCOMING)) {
460
        s->header.autoclear_features &= QED_AUTOCLEAR_FEATURE_MASK;
461

    
462
        ret = qed_write_header_sync(s);
463
        if (ret) {
464
            return ret;
465
        }
466

    
467
        /* From here on only known autoclear feature bits are valid */
468
        bdrv_flush(bs->file);
469
    }
470

    
471
    s->l1_table = qed_alloc_table(s);
472
    qed_init_l2_cache(&s->l2_cache);
473

    
474
    ret = qed_read_l1_table_sync(s);
475
    if (ret) {
476
        goto out;
477
    }
478

    
479
    /* If image was not closed cleanly, check consistency */
480
    if (!(flags & BDRV_O_CHECK) && (s->header.features & QED_F_NEED_CHECK)) {
481
        /* Read-only images cannot be fixed.  There is no risk of corruption
482
         * since write operations are not possible.  Therefore, allow
483
         * potentially inconsistent images to be opened read-only.  This can
484
         * aid data recovery from an otherwise inconsistent image.
485
         */
486
        if (!bdrv_is_read_only(bs->file) &&
487
            !(flags & BDRV_O_INCOMING)) {
488
            BdrvCheckResult result = {0};
489

    
490
            ret = qed_check(s, &result, true);
491
            if (ret) {
492
                goto out;
493
            }
494
        }
495
    }
496

    
497
    s->need_check_timer = qemu_new_timer_ns(vm_clock,
498
                                            qed_need_check_timer_cb, s);
499

    
500
out:
501
    if (ret) {
502
        qed_free_l2_cache(&s->l2_cache);
503
        qemu_vfree(s->l1_table);
504
    }
505
    return ret;
506
}
507

    
508
static void bdrv_qed_close(BlockDriverState *bs)
509
{
510
    BDRVQEDState *s = bs->opaque;
511

    
512
    qed_cancel_need_check_timer(s);
513
    qemu_free_timer(s->need_check_timer);
514

    
515
    /* Ensure writes reach stable storage */
516
    bdrv_flush(bs->file);
517

    
518
    /* Clean shutdown, no check required on next open */
519
    if (s->header.features & QED_F_NEED_CHECK) {
520
        s->header.features &= ~QED_F_NEED_CHECK;
521
        qed_write_header_sync(s);
522
    }
523

    
524
    qed_free_l2_cache(&s->l2_cache);
525
    qemu_vfree(s->l1_table);
526
}
527

    
528
static int qed_create(const char *filename, uint32_t cluster_size,
529
                      uint64_t image_size, uint32_t table_size,
530
                      const char *backing_file, const char *backing_fmt)
531
{
532
    QEDHeader header = {
533
        .magic = QED_MAGIC,
534
        .cluster_size = cluster_size,
535
        .table_size = table_size,
536
        .header_size = 1,
537
        .features = 0,
538
        .compat_features = 0,
539
        .l1_table_offset = cluster_size,
540
        .image_size = image_size,
541
    };
542
    QEDHeader le_header;
543
    uint8_t *l1_table = NULL;
544
    size_t l1_size = header.cluster_size * header.table_size;
545
    int ret = 0;
546
    BlockDriverState *bs = NULL;
547

    
548
    ret = bdrv_create_file(filename, NULL);
549
    if (ret < 0) {
550
        return ret;
551
    }
552

    
553
    ret = bdrv_file_open(&bs, filename, BDRV_O_RDWR | BDRV_O_CACHE_WB);
554
    if (ret < 0) {
555
        return ret;
556
    }
557

    
558
    /* File must start empty and grow, check truncate is supported */
559
    ret = bdrv_truncate(bs, 0);
560
    if (ret < 0) {
561
        goto out;
562
    }
563

    
564
    if (backing_file) {
565
        header.features |= QED_F_BACKING_FILE;
566
        header.backing_filename_offset = sizeof(le_header);
567
        header.backing_filename_size = strlen(backing_file);
568

    
569
        if (qed_fmt_is_raw(backing_fmt)) {
570
            header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
571
        }
572
    }
573

    
574
    qed_header_cpu_to_le(&header, &le_header);
575
    ret = bdrv_pwrite(bs, 0, &le_header, sizeof(le_header));
576
    if (ret < 0) {
577
        goto out;
578
    }
579
    ret = bdrv_pwrite(bs, sizeof(le_header), backing_file,
580
                      header.backing_filename_size);
581
    if (ret < 0) {
582
        goto out;
583
    }
584

    
585
    l1_table = g_malloc0(l1_size);
586
    ret = bdrv_pwrite(bs, header.l1_table_offset, l1_table, l1_size);
587
    if (ret < 0) {
588
        goto out;
589
    }
590

    
591
    ret = 0; /* success */
592
out:
593
    g_free(l1_table);
594
    bdrv_delete(bs);
595
    return ret;
596
}
597

    
598
static int bdrv_qed_create(const char *filename, QEMUOptionParameter *options)
599
{
600
    uint64_t image_size = 0;
601
    uint32_t cluster_size = QED_DEFAULT_CLUSTER_SIZE;
602
    uint32_t table_size = QED_DEFAULT_TABLE_SIZE;
603
    const char *backing_file = NULL;
604
    const char *backing_fmt = NULL;
605

    
606
    while (options && options->name) {
607
        if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
608
            image_size = options->value.n;
609
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
610
            backing_file = options->value.s;
611
        } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
612
            backing_fmt = options->value.s;
613
        } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
614
            if (options->value.n) {
615
                cluster_size = options->value.n;
616
            }
617
        } else if (!strcmp(options->name, BLOCK_OPT_TABLE_SIZE)) {
618
            if (options->value.n) {
619
                table_size = options->value.n;
620
            }
621
        }
622
        options++;
623
    }
624

    
625
    if (!qed_is_cluster_size_valid(cluster_size)) {
626
        fprintf(stderr, "QED cluster size must be within range [%u, %u] and power of 2\n",
627
                QED_MIN_CLUSTER_SIZE, QED_MAX_CLUSTER_SIZE);
628
        return -EINVAL;
629
    }
630
    if (!qed_is_table_size_valid(table_size)) {
631
        fprintf(stderr, "QED table size must be within range [%u, %u] and power of 2\n",
632
                QED_MIN_TABLE_SIZE, QED_MAX_TABLE_SIZE);
633
        return -EINVAL;
634
    }
635
    if (!qed_is_image_size_valid(image_size, cluster_size, table_size)) {
636
        fprintf(stderr, "QED image size must be a non-zero multiple of "
637
                        "cluster size and less than %" PRIu64 " bytes\n",
638
                qed_max_image_size(cluster_size, table_size));
639
        return -EINVAL;
640
    }
641

    
642
    return qed_create(filename, cluster_size, image_size, table_size,
643
                      backing_file, backing_fmt);
644
}
645

    
646
typedef struct {
647
    Coroutine *co;
648
    int is_allocated;
649
    int *pnum;
650
} QEDIsAllocatedCB;
651

    
652
static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t len)
653
{
654
    QEDIsAllocatedCB *cb = opaque;
655
    *cb->pnum = len / BDRV_SECTOR_SIZE;
656
    cb->is_allocated = (ret == QED_CLUSTER_FOUND || ret == QED_CLUSTER_ZERO);
657
    if (cb->co) {
658
        qemu_coroutine_enter(cb->co, NULL);
659
    }
660
}
661

    
662
static int coroutine_fn bdrv_qed_co_is_allocated(BlockDriverState *bs,
663
                                                 int64_t sector_num,
664
                                                 int nb_sectors, int *pnum)
665
{
666
    BDRVQEDState *s = bs->opaque;
667
    uint64_t pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
668
    size_t len = (size_t)nb_sectors * BDRV_SECTOR_SIZE;
669
    QEDIsAllocatedCB cb = {
670
        .is_allocated = -1,
671
        .pnum = pnum,
672
    };
673
    QEDRequest request = { .l2_table = NULL };
674

    
675
    qed_find_cluster(s, &request, pos, len, qed_is_allocated_cb, &cb);
676

    
677
    /* Now sleep if the callback wasn't invoked immediately */
678
    while (cb.is_allocated == -1) {
679
        cb.co = qemu_coroutine_self();
680
        qemu_coroutine_yield();
681
    }
682

    
683
    qed_unref_l2_cache_entry(request.l2_table);
684

    
685
    return cb.is_allocated;
686
}
687

    
688
static int bdrv_qed_make_empty(BlockDriverState *bs)
689
{
690
    return -ENOTSUP;
691
}
692

    
693
static BDRVQEDState *acb_to_s(QEDAIOCB *acb)
694
{
695
    return acb->common.bs->opaque;
696
}
697

    
698
/**
699
 * Read from the backing file or zero-fill if no backing file
700
 *
701
 * @s:          QED state
702
 * @pos:        Byte position in device
703
 * @qiov:       Destination I/O vector
704
 * @cb:         Completion function
705
 * @opaque:     User data for completion function
706
 *
707
 * This function reads qiov->size bytes starting at pos from the backing file.
708
 * If there is no backing file then zeroes are read.
709
 */
710
static void qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
711
                                  QEMUIOVector *qiov,
712
                                  BlockDriverCompletionFunc *cb, void *opaque)
713
{
714
    uint64_t backing_length = 0;
715
    size_t size;
716

    
717
    /* If there is a backing file, get its length.  Treat the absence of a
718
     * backing file like a zero length backing file.
719
     */
720
    if (s->bs->backing_hd) {
721
        int64_t l = bdrv_getlength(s->bs->backing_hd);
722
        if (l < 0) {
723
            cb(opaque, l);
724
            return;
725
        }
726
        backing_length = l;
727
    }
728

    
729
    /* Zero all sectors if reading beyond the end of the backing file */
730
    if (pos >= backing_length ||
731
        pos + qiov->size > backing_length) {
732
        qemu_iovec_memset(qiov, 0, 0, qiov->size);
733
    }
734

    
735
    /* Complete now if there are no backing file sectors to read */
736
    if (pos >= backing_length) {
737
        cb(opaque, 0);
738
        return;
739
    }
740

    
741
    /* If the read straddles the end of the backing file, shorten it */
742
    size = MIN((uint64_t)backing_length - pos, qiov->size);
743

    
744
    BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO);
745
    bdrv_aio_readv(s->bs->backing_hd, pos / BDRV_SECTOR_SIZE,
746
                   qiov, size / BDRV_SECTOR_SIZE, cb, opaque);
747
}
748

    
749
typedef struct {
750
    GenericCB gencb;
751
    BDRVQEDState *s;
752
    QEMUIOVector qiov;
753
    struct iovec iov;
754
    uint64_t offset;
755
} CopyFromBackingFileCB;
756

    
757
static void qed_copy_from_backing_file_cb(void *opaque, int ret)
758
{
759
    CopyFromBackingFileCB *copy_cb = opaque;
760
    qemu_vfree(copy_cb->iov.iov_base);
761
    gencb_complete(&copy_cb->gencb, ret);
762
}
763

    
764
static void qed_copy_from_backing_file_write(void *opaque, int ret)
765
{
766
    CopyFromBackingFileCB *copy_cb = opaque;
767
    BDRVQEDState *s = copy_cb->s;
768

    
769
    if (ret) {
770
        qed_copy_from_backing_file_cb(copy_cb, ret);
771
        return;
772
    }
773

    
774
    BLKDBG_EVENT(s->bs->file, BLKDBG_COW_WRITE);
775
    bdrv_aio_writev(s->bs->file, copy_cb->offset / BDRV_SECTOR_SIZE,
776
                    &copy_cb->qiov, copy_cb->qiov.size / BDRV_SECTOR_SIZE,
777
                    qed_copy_from_backing_file_cb, copy_cb);
778
}
779

    
780
/**
781
 * Copy data from backing file into the image
782
 *
783
 * @s:          QED state
784
 * @pos:        Byte position in device
785
 * @len:        Number of bytes
786
 * @offset:     Byte offset in image file
787
 * @cb:         Completion function
788
 * @opaque:     User data for completion function
789
 */
790
static void qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos,
791
                                       uint64_t len, uint64_t offset,
792
                                       BlockDriverCompletionFunc *cb,
793
                                       void *opaque)
794
{
795
    CopyFromBackingFileCB *copy_cb;
796

    
797
    /* Skip copy entirely if there is no work to do */
798
    if (len == 0) {
799
        cb(opaque, 0);
800
        return;
801
    }
802

    
803
    copy_cb = gencb_alloc(sizeof(*copy_cb), cb, opaque);
804
    copy_cb->s = s;
805
    copy_cb->offset = offset;
806
    copy_cb->iov.iov_base = qemu_blockalign(s->bs, len);
807
    copy_cb->iov.iov_len = len;
808
    qemu_iovec_init_external(&copy_cb->qiov, &copy_cb->iov, 1);
809

    
810
    qed_read_backing_file(s, pos, &copy_cb->qiov,
811
                          qed_copy_from_backing_file_write, copy_cb);
812
}
813

    
814
/**
815
 * Link one or more contiguous clusters into a table
816
 *
817
 * @s:              QED state
818
 * @table:          L2 table
819
 * @index:          First cluster index
820
 * @n:              Number of contiguous clusters
821
 * @cluster:        First cluster offset
822
 *
823
 * The cluster offset may be an allocated byte offset in the image file, the
824
 * zero cluster marker, or the unallocated cluster marker.
825
 */
826
static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index,
827
                                unsigned int n, uint64_t cluster)
828
{
829
    int i;
830
    for (i = index; i < index + n; i++) {
831
        table->offsets[i] = cluster;
832
        if (!qed_offset_is_unalloc_cluster(cluster) &&
833
            !qed_offset_is_zero_cluster(cluster)) {
834
            cluster += s->header.cluster_size;
835
        }
836
    }
837
}
838

    
839
static void qed_aio_complete_bh(void *opaque)
840
{
841
    QEDAIOCB *acb = opaque;
842
    BlockDriverCompletionFunc *cb = acb->common.cb;
843
    void *user_opaque = acb->common.opaque;
844
    int ret = acb->bh_ret;
845
    bool *finished = acb->finished;
846

    
847
    qemu_bh_delete(acb->bh);
848
    qemu_aio_release(acb);
849

    
850
    /* Invoke callback */
851
    cb(user_opaque, ret);
852

    
853
    /* Signal cancel completion */
854
    if (finished) {
855
        *finished = true;
856
    }
857
}
858

    
859
static void qed_aio_complete(QEDAIOCB *acb, int ret)
860
{
861
    BDRVQEDState *s = acb_to_s(acb);
862

    
863
    trace_qed_aio_complete(s, acb, ret);
864

    
865
    /* Free resources */
866
    qemu_iovec_destroy(&acb->cur_qiov);
867
    qed_unref_l2_cache_entry(acb->request.l2_table);
868

    
869
    /* Free the buffer we may have allocated for zero writes */
870
    if (acb->flags & QED_AIOCB_ZERO) {
871
        qemu_vfree(acb->qiov->iov[0].iov_base);
872
        acb->qiov->iov[0].iov_base = NULL;
873
    }
874

    
875
    /* Arrange for a bh to invoke the completion function */
876
    acb->bh_ret = ret;
877
    acb->bh = qemu_bh_new(qed_aio_complete_bh, acb);
878
    qemu_bh_schedule(acb->bh);
879

    
880
    /* Start next allocating write request waiting behind this one.  Note that
881
     * requests enqueue themselves when they first hit an unallocated cluster
882
     * but they wait until the entire request is finished before waking up the
883
     * next request in the queue.  This ensures that we don't cycle through
884
     * requests multiple times but rather finish one at a time completely.
885
     */
886
    if (acb == QSIMPLEQ_FIRST(&s->allocating_write_reqs)) {
887
        QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next);
888
        acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
889
        if (acb) {
890
            qed_aio_next_io(acb, 0);
891
        } else if (s->header.features & QED_F_NEED_CHECK) {
892
            qed_start_need_check_timer(s);
893
        }
894
    }
895
}
896

    
897
/**
898
 * Commit the current L2 table to the cache
899
 */
900
static void qed_commit_l2_update(void *opaque, int ret)
901
{
902
    QEDAIOCB *acb = opaque;
903
    BDRVQEDState *s = acb_to_s(acb);
904
    CachedL2Table *l2_table = acb->request.l2_table;
905
    uint64_t l2_offset = l2_table->offset;
906

    
907
    qed_commit_l2_cache_entry(&s->l2_cache, l2_table);
908

    
909
    /* This is guaranteed to succeed because we just committed the entry to the
910
     * cache.
911
     */
912
    acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
913
    assert(acb->request.l2_table != NULL);
914

    
915
    qed_aio_next_io(opaque, ret);
916
}
917

    
918
/**
919
 * Update L1 table with new L2 table offset and write it out
920
 */
921
static void qed_aio_write_l1_update(void *opaque, int ret)
922
{
923
    QEDAIOCB *acb = opaque;
924
    BDRVQEDState *s = acb_to_s(acb);
925
    int index;
926

    
927
    if (ret) {
928
        qed_aio_complete(acb, ret);
929
        return;
930
    }
931

    
932
    index = qed_l1_index(s, acb->cur_pos);
933
    s->l1_table->offsets[index] = acb->request.l2_table->offset;
934

    
935
    qed_write_l1_table(s, index, 1, qed_commit_l2_update, acb);
936
}
937

    
938
/**
939
 * Update L2 table with new cluster offsets and write them out
940
 */
941
static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset)
942
{
943
    BDRVQEDState *s = acb_to_s(acb);
944
    bool need_alloc = acb->find_cluster_ret == QED_CLUSTER_L1;
945
    int index;
946

    
947
    if (ret) {
948
        goto err;
949
    }
950

    
951
    if (need_alloc) {
952
        qed_unref_l2_cache_entry(acb->request.l2_table);
953
        acb->request.l2_table = qed_new_l2_table(s);
954
    }
955

    
956
    index = qed_l2_index(s, acb->cur_pos);
957
    qed_update_l2_table(s, acb->request.l2_table->table, index, acb->cur_nclusters,
958
                         offset);
959

    
960
    if (need_alloc) {
961
        /* Write out the whole new L2 table */
962
        qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true,
963
                            qed_aio_write_l1_update, acb);
964
    } else {
965
        /* Write out only the updated part of the L2 table */
966
        qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false,
967
                            qed_aio_next_io, acb);
968
    }
969
    return;
970

    
971
err:
972
    qed_aio_complete(acb, ret);
973
}
974

    
975
static void qed_aio_write_l2_update_cb(void *opaque, int ret)
976
{
977
    QEDAIOCB *acb = opaque;
978
    qed_aio_write_l2_update(acb, ret, acb->cur_cluster);
979
}
980

    
981
/**
982
 * Flush new data clusters before updating the L2 table
983
 *
984
 * This flush is necessary when a backing file is in use.  A crash during an
985
 * allocating write could result in empty clusters in the image.  If the write
986
 * only touched a subregion of the cluster, then backing image sectors have
987
 * been lost in the untouched region.  The solution is to flush after writing a
988
 * new data cluster and before updating the L2 table.
989
 */
990
static void qed_aio_write_flush_before_l2_update(void *opaque, int ret)
991
{
992
    QEDAIOCB *acb = opaque;
993
    BDRVQEDState *s = acb_to_s(acb);
994

    
995
    if (!bdrv_aio_flush(s->bs->file, qed_aio_write_l2_update_cb, opaque)) {
996
        qed_aio_complete(acb, -EIO);
997
    }
998
}
999

    
1000
/**
1001
 * Write data to the image file
1002
 */
1003
static void qed_aio_write_main(void *opaque, int ret)
1004
{
1005
    QEDAIOCB *acb = opaque;
1006
    BDRVQEDState *s = acb_to_s(acb);
1007
    uint64_t offset = acb->cur_cluster +
1008
                      qed_offset_into_cluster(s, acb->cur_pos);
1009
    BlockDriverCompletionFunc *next_fn;
1010

    
1011
    trace_qed_aio_write_main(s, acb, ret, offset, acb->cur_qiov.size);
1012

    
1013
    if (ret) {
1014
        qed_aio_complete(acb, ret);
1015
        return;
1016
    }
1017

    
1018
    if (acb->find_cluster_ret == QED_CLUSTER_FOUND) {
1019
        next_fn = qed_aio_next_io;
1020
    } else {
1021
        if (s->bs->backing_hd) {
1022
            next_fn = qed_aio_write_flush_before_l2_update;
1023
        } else {
1024
            next_fn = qed_aio_write_l2_update_cb;
1025
        }
1026
    }
1027

    
1028
    BLKDBG_EVENT(s->bs->file, BLKDBG_WRITE_AIO);
1029
    bdrv_aio_writev(s->bs->file, offset / BDRV_SECTOR_SIZE,
1030
                    &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE,
1031
                    next_fn, acb);
1032
}
1033

    
1034
/**
1035
 * Populate back untouched region of new data cluster
1036
 */
1037
static void qed_aio_write_postfill(void *opaque, int ret)
1038
{
1039
    QEDAIOCB *acb = opaque;
1040
    BDRVQEDState *s = acb_to_s(acb);
1041
    uint64_t start = acb->cur_pos + acb->cur_qiov.size;
1042
    uint64_t len =
1043
        qed_start_of_cluster(s, start + s->header.cluster_size - 1) - start;
1044
    uint64_t offset = acb->cur_cluster +
1045
                      qed_offset_into_cluster(s, acb->cur_pos) +
1046
                      acb->cur_qiov.size;
1047

    
1048
    if (ret) {
1049
        qed_aio_complete(acb, ret);
1050
        return;
1051
    }
1052

    
1053
    trace_qed_aio_write_postfill(s, acb, start, len, offset);
1054
    qed_copy_from_backing_file(s, start, len, offset,
1055
                                qed_aio_write_main, acb);
1056
}
1057

    
1058
/**
1059
 * Populate front untouched region of new data cluster
1060
 */
1061
static void qed_aio_write_prefill(void *opaque, int ret)
1062
{
1063
    QEDAIOCB *acb = opaque;
1064
    BDRVQEDState *s = acb_to_s(acb);
1065
    uint64_t start = qed_start_of_cluster(s, acb->cur_pos);
1066
    uint64_t len = qed_offset_into_cluster(s, acb->cur_pos);
1067

    
1068
    trace_qed_aio_write_prefill(s, acb, start, len, acb->cur_cluster);
1069
    qed_copy_from_backing_file(s, start, len, acb->cur_cluster,
1070
                                qed_aio_write_postfill, acb);
1071
}
1072

    
1073
/**
1074
 * Check if the QED_F_NEED_CHECK bit should be set during allocating write
1075
 */
1076
static bool qed_should_set_need_check(BDRVQEDState *s)
1077
{
1078
    /* The flush before L2 update path ensures consistency */
1079
    if (s->bs->backing_hd) {
1080
        return false;
1081
    }
1082

    
1083
    return !(s->header.features & QED_F_NEED_CHECK);
1084
}
1085

    
1086
static void qed_aio_write_zero_cluster(void *opaque, int ret)
1087
{
1088
    QEDAIOCB *acb = opaque;
1089

    
1090
    if (ret) {
1091
        qed_aio_complete(acb, ret);
1092
        return;
1093
    }
1094

    
1095
    qed_aio_write_l2_update(acb, 0, 1);
1096
}
1097

    
1098
/**
1099
 * Write new data cluster
1100
 *
1101
 * @acb:        Write request
1102
 * @len:        Length in bytes
1103
 *
1104
 * This path is taken when writing to previously unallocated clusters.
1105
 */
1106
static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
1107
{
1108
    BDRVQEDState *s = acb_to_s(acb);
1109
    BlockDriverCompletionFunc *cb;
1110

    
1111
    /* Cancel timer when the first allocating request comes in */
1112
    if (QSIMPLEQ_EMPTY(&s->allocating_write_reqs)) {
1113
        qed_cancel_need_check_timer(s);
1114
    }
1115

    
1116
    /* Freeze this request if another allocating write is in progress */
1117
    if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs)) {
1118
        QSIMPLEQ_INSERT_TAIL(&s->allocating_write_reqs, acb, next);
1119
    }
1120
    if (acb != QSIMPLEQ_FIRST(&s->allocating_write_reqs) ||
1121
        s->allocating_write_reqs_plugged) {
1122
        return; /* wait for existing request to finish */
1123
    }
1124

    
1125
    acb->cur_nclusters = qed_bytes_to_clusters(s,
1126
            qed_offset_into_cluster(s, acb->cur_pos) + len);
1127
    qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
1128

    
1129
    if (acb->flags & QED_AIOCB_ZERO) {
1130
        /* Skip ahead if the clusters are already zero */
1131
        if (acb->find_cluster_ret == QED_CLUSTER_ZERO) {
1132
            qed_aio_next_io(acb, 0);
1133
            return;
1134
        }
1135

    
1136
        cb = qed_aio_write_zero_cluster;
1137
    } else {
1138
        cb = qed_aio_write_prefill;
1139
        acb->cur_cluster = qed_alloc_clusters(s, acb->cur_nclusters);
1140
    }
1141

    
1142
    if (qed_should_set_need_check(s)) {
1143
        s->header.features |= QED_F_NEED_CHECK;
1144
        qed_write_header(s, cb, acb);
1145
    } else {
1146
        cb(acb, 0);
1147
    }
1148
}
1149

    
1150
/**
1151
 * Write data cluster in place
1152
 *
1153
 * @acb:        Write request
1154
 * @offset:     Cluster offset in bytes
1155
 * @len:        Length in bytes
1156
 *
1157
 * This path is taken when writing to already allocated clusters.
1158
 */
1159
static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
1160
{
1161
    /* Allocate buffer for zero writes */
1162
    if (acb->flags & QED_AIOCB_ZERO) {
1163
        struct iovec *iov = acb->qiov->iov;
1164

    
1165
        if (!iov->iov_base) {
1166
            iov->iov_base = qemu_blockalign(acb->common.bs, iov->iov_len);
1167
            memset(iov->iov_base, 0, iov->iov_len);
1168
        }
1169
    }
1170

    
1171
    /* Calculate the I/O vector */
1172
    acb->cur_cluster = offset;
1173
    qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
1174

    
1175
    /* Do the actual write */
1176
    qed_aio_write_main(acb, 0);
1177
}
1178

    
1179
/**
1180
 * Write data cluster
1181
 *
1182
 * @opaque:     Write request
1183
 * @ret:        QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1,
1184
 *              or -errno
1185
 * @offset:     Cluster offset in bytes
1186
 * @len:        Length in bytes
1187
 *
1188
 * Callback from qed_find_cluster().
1189
 */
1190
static void qed_aio_write_data(void *opaque, int ret,
1191
                               uint64_t offset, size_t len)
1192
{
1193
    QEDAIOCB *acb = opaque;
1194

    
1195
    trace_qed_aio_write_data(acb_to_s(acb), acb, ret, offset, len);
1196

    
1197
    acb->find_cluster_ret = ret;
1198

    
1199
    switch (ret) {
1200
    case QED_CLUSTER_FOUND:
1201
        qed_aio_write_inplace(acb, offset, len);
1202
        break;
1203

    
1204
    case QED_CLUSTER_L2:
1205
    case QED_CLUSTER_L1:
1206
    case QED_CLUSTER_ZERO:
1207
        qed_aio_write_alloc(acb, len);
1208
        break;
1209

    
1210
    default:
1211
        qed_aio_complete(acb, ret);
1212
        break;
1213
    }
1214
}
1215

    
1216
/**
1217
 * Read data cluster
1218
 *
1219
 * @opaque:     Read request
1220
 * @ret:        QED_CLUSTER_FOUND, QED_CLUSTER_L2, QED_CLUSTER_L1,
1221
 *              or -errno
1222
 * @offset:     Cluster offset in bytes
1223
 * @len:        Length in bytes
1224
 *
1225
 * Callback from qed_find_cluster().
1226
 */
1227
static void qed_aio_read_data(void *opaque, int ret,
1228
                              uint64_t offset, size_t len)
1229
{
1230
    QEDAIOCB *acb = opaque;
1231
    BDRVQEDState *s = acb_to_s(acb);
1232
    BlockDriverState *bs = acb->common.bs;
1233

    
1234
    /* Adjust offset into cluster */
1235
    offset += qed_offset_into_cluster(s, acb->cur_pos);
1236

    
1237
    trace_qed_aio_read_data(s, acb, ret, offset, len);
1238

    
1239
    if (ret < 0) {
1240
        goto err;
1241
    }
1242

    
1243
    qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
1244

    
1245
    /* Handle zero cluster and backing file reads */
1246
    if (ret == QED_CLUSTER_ZERO) {
1247
        qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size);
1248
        qed_aio_next_io(acb, 0);
1249
        return;
1250
    } else if (ret != QED_CLUSTER_FOUND) {
1251
        qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov,
1252
                              qed_aio_next_io, acb);
1253
        return;
1254
    }
1255

    
1256
    BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
1257
    bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE,
1258
                   &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE,
1259
                   qed_aio_next_io, acb);
1260
    return;
1261

    
1262
err:
1263
    qed_aio_complete(acb, ret);
1264
}
1265

    
1266
/**
1267
 * Begin next I/O or complete the request
1268
 */
1269
static void qed_aio_next_io(void *opaque, int ret)
1270
{
1271
    QEDAIOCB *acb = opaque;
1272
    BDRVQEDState *s = acb_to_s(acb);
1273
    QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ?
1274
                                qed_aio_write_data : qed_aio_read_data;
1275

    
1276
    trace_qed_aio_next_io(s, acb, ret, acb->cur_pos + acb->cur_qiov.size);
1277

    
1278
    /* Handle I/O error */
1279
    if (ret) {
1280
        qed_aio_complete(acb, ret);
1281
        return;
1282
    }
1283

    
1284
    acb->qiov_offset += acb->cur_qiov.size;
1285
    acb->cur_pos += acb->cur_qiov.size;
1286
    qemu_iovec_reset(&acb->cur_qiov);
1287

    
1288
    /* Complete request */
1289
    if (acb->cur_pos >= acb->end_pos) {
1290
        qed_aio_complete(acb, 0);
1291
        return;
1292
    }
1293

    
1294
    /* Find next cluster and start I/O */
1295
    qed_find_cluster(s, &acb->request,
1296
                      acb->cur_pos, acb->end_pos - acb->cur_pos,
1297
                      io_fn, acb);
1298
}
1299

    
1300
static BlockDriverAIOCB *qed_aio_setup(BlockDriverState *bs,
1301
                                       int64_t sector_num,
1302
                                       QEMUIOVector *qiov, int nb_sectors,
1303
                                       BlockDriverCompletionFunc *cb,
1304
                                       void *opaque, int flags)
1305
{
1306
    QEDAIOCB *acb = qemu_aio_get(&qed_aio_pool, bs, cb, opaque);
1307

    
1308
    trace_qed_aio_setup(bs->opaque, acb, sector_num, nb_sectors,
1309
                        opaque, flags);
1310

    
1311
    acb->flags = flags;
1312
    acb->finished = NULL;
1313
    acb->qiov = qiov;
1314
    acb->qiov_offset = 0;
1315
    acb->cur_pos = (uint64_t)sector_num * BDRV_SECTOR_SIZE;
1316
    acb->end_pos = acb->cur_pos + nb_sectors * BDRV_SECTOR_SIZE;
1317
    acb->request.l2_table = NULL;
1318
    qemu_iovec_init(&acb->cur_qiov, qiov->niov);
1319

    
1320
    /* Start request */
1321
    qed_aio_next_io(acb, 0);
1322
    return &acb->common;
1323
}
1324

    
1325
static BlockDriverAIOCB *bdrv_qed_aio_readv(BlockDriverState *bs,
1326
                                            int64_t sector_num,
1327
                                            QEMUIOVector *qiov, int nb_sectors,
1328
                                            BlockDriverCompletionFunc *cb,
1329
                                            void *opaque)
1330
{
1331
    return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
1332
}
1333

    
1334
static BlockDriverAIOCB *bdrv_qed_aio_writev(BlockDriverState *bs,
1335
                                             int64_t sector_num,
1336
                                             QEMUIOVector *qiov, int nb_sectors,
1337
                                             BlockDriverCompletionFunc *cb,
1338
                                             void *opaque)
1339
{
1340
    return qed_aio_setup(bs, sector_num, qiov, nb_sectors, cb,
1341
                         opaque, QED_AIOCB_WRITE);
1342
}
1343

    
1344
typedef struct {
1345
    Coroutine *co;
1346
    int ret;
1347
    bool done;
1348
} QEDWriteZeroesCB;
1349

    
1350
static void coroutine_fn qed_co_write_zeroes_cb(void *opaque, int ret)
1351
{
1352
    QEDWriteZeroesCB *cb = opaque;
1353

    
1354
    cb->done = true;
1355
    cb->ret = ret;
1356
    if (cb->co) {
1357
        qemu_coroutine_enter(cb->co, NULL);
1358
    }
1359
}
1360

    
1361
static int coroutine_fn bdrv_qed_co_write_zeroes(BlockDriverState *bs,
1362
                                                 int64_t sector_num,
1363
                                                 int nb_sectors)
1364
{
1365
    BlockDriverAIOCB *blockacb;
1366
    BDRVQEDState *s = bs->opaque;
1367
    QEDWriteZeroesCB cb = { .done = false };
1368
    QEMUIOVector qiov;
1369
    struct iovec iov;
1370

    
1371
    /* Refuse if there are untouched backing file sectors */
1372
    if (bs->backing_hd) {
1373
        if (qed_offset_into_cluster(s, sector_num * BDRV_SECTOR_SIZE) != 0) {
1374
            return -ENOTSUP;
1375
        }
1376
        if (qed_offset_into_cluster(s, nb_sectors * BDRV_SECTOR_SIZE) != 0) {
1377
            return -ENOTSUP;
1378
        }
1379
    }
1380

    
1381
    /* Zero writes start without an I/O buffer.  If a buffer becomes necessary
1382
     * then it will be allocated during request processing.
1383
     */
1384
    iov.iov_base = NULL,
1385
    iov.iov_len  = nb_sectors * BDRV_SECTOR_SIZE,
1386

    
1387
    qemu_iovec_init_external(&qiov, &iov, 1);
1388
    blockacb = qed_aio_setup(bs, sector_num, &qiov, nb_sectors,
1389
                             qed_co_write_zeroes_cb, &cb,
1390
                             QED_AIOCB_WRITE | QED_AIOCB_ZERO);
1391
    if (!blockacb) {
1392
        return -EIO;
1393
    }
1394
    if (!cb.done) {
1395
        cb.co = qemu_coroutine_self();
1396
        qemu_coroutine_yield();
1397
    }
1398
    assert(cb.done);
1399
    return cb.ret;
1400
}
1401

    
1402
static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
1403
{
1404
    BDRVQEDState *s = bs->opaque;
1405
    uint64_t old_image_size;
1406
    int ret;
1407

    
1408
    if (!qed_is_image_size_valid(offset, s->header.cluster_size,
1409
                                 s->header.table_size)) {
1410
        return -EINVAL;
1411
    }
1412

    
1413
    /* Shrinking is currently not supported */
1414
    if ((uint64_t)offset < s->header.image_size) {
1415
        return -ENOTSUP;
1416
    }
1417

    
1418
    old_image_size = s->header.image_size;
1419
    s->header.image_size = offset;
1420
    ret = qed_write_header_sync(s);
1421
    if (ret < 0) {
1422
        s->header.image_size = old_image_size;
1423
    }
1424
    return ret;
1425
}
1426

    
1427
static int64_t bdrv_qed_getlength(BlockDriverState *bs)
1428
{
1429
    BDRVQEDState *s = bs->opaque;
1430
    return s->header.image_size;
1431
}
1432

    
1433
static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1434
{
1435
    BDRVQEDState *s = bs->opaque;
1436

    
1437
    memset(bdi, 0, sizeof(*bdi));
1438
    bdi->cluster_size = s->header.cluster_size;
1439
    bdi->is_dirty = s->header.features & QED_F_NEED_CHECK;
1440
    return 0;
1441
}
1442

    
1443
static int bdrv_qed_change_backing_file(BlockDriverState *bs,
1444
                                        const char *backing_file,
1445
                                        const char *backing_fmt)
1446
{
1447
    BDRVQEDState *s = bs->opaque;
1448
    QEDHeader new_header, le_header;
1449
    void *buffer;
1450
    size_t buffer_len, backing_file_len;
1451
    int ret;
1452

    
1453
    /* Refuse to set backing filename if unknown compat feature bits are
1454
     * active.  If the image uses an unknown compat feature then we may not
1455
     * know the layout of data following the header structure and cannot safely
1456
     * add a new string.
1457
     */
1458
    if (backing_file && (s->header.compat_features &
1459
                         ~QED_COMPAT_FEATURE_MASK)) {
1460
        return -ENOTSUP;
1461
    }
1462

    
1463
    memcpy(&new_header, &s->header, sizeof(new_header));
1464

    
1465
    new_header.features &= ~(QED_F_BACKING_FILE |
1466
                             QED_F_BACKING_FORMAT_NO_PROBE);
1467

    
1468
    /* Adjust feature flags */
1469
    if (backing_file) {
1470
        new_header.features |= QED_F_BACKING_FILE;
1471

    
1472
        if (qed_fmt_is_raw(backing_fmt)) {
1473
            new_header.features |= QED_F_BACKING_FORMAT_NO_PROBE;
1474
        }
1475
    }
1476

    
1477
    /* Calculate new header size */
1478
    backing_file_len = 0;
1479

    
1480
    if (backing_file) {
1481
        backing_file_len = strlen(backing_file);
1482
    }
1483

    
1484
    buffer_len = sizeof(new_header);
1485
    new_header.backing_filename_offset = buffer_len;
1486
    new_header.backing_filename_size = backing_file_len;
1487
    buffer_len += backing_file_len;
1488

    
1489
    /* Make sure we can rewrite header without failing */
1490
    if (buffer_len > new_header.header_size * new_header.cluster_size) {
1491
        return -ENOSPC;
1492
    }
1493

    
1494
    /* Prepare new header */
1495
    buffer = g_malloc(buffer_len);
1496

    
1497
    qed_header_cpu_to_le(&new_header, &le_header);
1498
    memcpy(buffer, &le_header, sizeof(le_header));
1499
    buffer_len = sizeof(le_header);
1500

    
1501
    if (backing_file) {
1502
        memcpy(buffer + buffer_len, backing_file, backing_file_len);
1503
        buffer_len += backing_file_len;
1504
    }
1505

    
1506
    /* Write new header */
1507
    ret = bdrv_pwrite_sync(bs->file, 0, buffer, buffer_len);
1508
    g_free(buffer);
1509
    if (ret == 0) {
1510
        memcpy(&s->header, &new_header, sizeof(new_header));
1511
    }
1512
    return ret;
1513
}
1514

    
1515
static void bdrv_qed_invalidate_cache(BlockDriverState *bs)
1516
{
1517
    BDRVQEDState *s = bs->opaque;
1518

    
1519
    bdrv_qed_close(bs);
1520
    memset(s, 0, sizeof(BDRVQEDState));
1521
    bdrv_qed_open(bs, bs->open_flags);
1522
}
1523

    
1524
static int bdrv_qed_check(BlockDriverState *bs, BdrvCheckResult *result,
1525
                          BdrvCheckMode fix)
1526
{
1527
    BDRVQEDState *s = bs->opaque;
1528

    
1529
    return qed_check(s, result, !!fix);
1530
}
1531

    
1532
static QEMUOptionParameter qed_create_options[] = {
1533
    {
1534
        .name = BLOCK_OPT_SIZE,
1535
        .type = OPT_SIZE,
1536
        .help = "Virtual disk size (in bytes)"
1537
    }, {
1538
        .name = BLOCK_OPT_BACKING_FILE,
1539
        .type = OPT_STRING,
1540
        .help = "File name of a base image"
1541
    }, {
1542
        .name = BLOCK_OPT_BACKING_FMT,
1543
        .type = OPT_STRING,
1544
        .help = "Image format of the base image"
1545
    }, {
1546
        .name = BLOCK_OPT_CLUSTER_SIZE,
1547
        .type = OPT_SIZE,
1548
        .help = "Cluster size (in bytes)",
1549
        .value = { .n = QED_DEFAULT_CLUSTER_SIZE },
1550
    }, {
1551
        .name = BLOCK_OPT_TABLE_SIZE,
1552
        .type = OPT_SIZE,
1553
        .help = "L1/L2 table size (in clusters)"
1554
    },
1555
    { /* end of list */ }
1556
};
1557

    
1558
static BlockDriver bdrv_qed = {
1559
    .format_name              = "qed",
1560
    .instance_size            = sizeof(BDRVQEDState),
1561
    .create_options           = qed_create_options,
1562

    
1563
    .bdrv_probe               = bdrv_qed_probe,
1564
    .bdrv_rebind              = bdrv_qed_rebind,
1565
    .bdrv_open                = bdrv_qed_open,
1566
    .bdrv_close               = bdrv_qed_close,
1567
    .bdrv_create              = bdrv_qed_create,
1568
    .bdrv_co_is_allocated     = bdrv_qed_co_is_allocated,
1569
    .bdrv_make_empty          = bdrv_qed_make_empty,
1570
    .bdrv_aio_readv           = bdrv_qed_aio_readv,
1571
    .bdrv_aio_writev          = bdrv_qed_aio_writev,
1572
    .bdrv_co_write_zeroes     = bdrv_qed_co_write_zeroes,
1573
    .bdrv_truncate            = bdrv_qed_truncate,
1574
    .bdrv_getlength           = bdrv_qed_getlength,
1575
    .bdrv_get_info            = bdrv_qed_get_info,
1576
    .bdrv_change_backing_file = bdrv_qed_change_backing_file,
1577
    .bdrv_invalidate_cache    = bdrv_qed_invalidate_cache,
1578
    .bdrv_check               = bdrv_qed_check,
1579
};
1580

    
1581
static void bdrv_qed_init(void)
1582
{
1583
    bdrv_register(&bdrv_qed);
1584
}
1585

    
1586
block_init(bdrv_qed_init);