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25#include "qemu/osdep.h"
26#include "sysemu/block-backend.h"
27#include "qapi/error.h"
28#include "qcow2.h"
29#include "qemu/bswap.h"
30#include "qemu/error-report.h"
31#include "qemu/cutils.h"
32#include "qemu/memalign.h"
33
34static void qcow2_free_single_snapshot(BlockDriverState *bs, int i)
35{
36 BDRVQcow2State *s = bs->opaque;
37
38 assert(i >= 0 && i < s->nb_snapshots);
39 g_free(s->snapshots[i].name);
40 g_free(s->snapshots[i].id_str);
41 g_free(s->snapshots[i].unknown_extra_data);
42 memset(&s->snapshots[i], 0, sizeof(s->snapshots[i]));
43}
44
45void qcow2_free_snapshots(BlockDriverState *bs)
46{
47 BDRVQcow2State *s = bs->opaque;
48 int i;
49
50 for(i = 0; i < s->nb_snapshots; i++) {
51 qcow2_free_single_snapshot(bs, i);
52 }
53 g_free(s->snapshots);
54 s->snapshots = NULL;
55 s->nb_snapshots = 0;
56}
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80static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair,
81 int *nb_clusters_reduced,
82 int *extra_data_dropped,
83 Error **errp)
84{
85 BDRVQcow2State *s = bs->opaque;
86 QCowSnapshotHeader h;
87 QCowSnapshotExtraData extra;
88 QCowSnapshot *sn;
89 int i, id_str_size, name_size;
90 int64_t offset, pre_sn_offset;
91 uint64_t table_length = 0;
92 int ret;
93
94 if (!s->nb_snapshots) {
95 s->snapshots = NULL;
96 s->snapshots_size = 0;
97 return 0;
98 }
99
100 offset = s->snapshots_offset;
101 s->snapshots = g_new0(QCowSnapshot, s->nb_snapshots);
102
103 for(i = 0; i < s->nb_snapshots; i++) {
104 bool truncate_unknown_extra_data = false;
105
106 pre_sn_offset = offset;
107 table_length = ROUND_UP(table_length, 8);
108
109
110 offset = ROUND_UP(offset, 8);
111 ret = bdrv_pread(bs->file, offset, &h, sizeof(h));
112 if (ret < 0) {
113 error_setg_errno(errp, -ret, "Failed to read snapshot table");
114 goto fail;
115 }
116
117 offset += sizeof(h);
118 sn = s->snapshots + i;
119 sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
120 sn->l1_size = be32_to_cpu(h.l1_size);
121 sn->vm_state_size = be32_to_cpu(h.vm_state_size);
122 sn->date_sec = be32_to_cpu(h.date_sec);
123 sn->date_nsec = be32_to_cpu(h.date_nsec);
124 sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
125 sn->extra_data_size = be32_to_cpu(h.extra_data_size);
126
127 id_str_size = be16_to_cpu(h.id_str_size);
128 name_size = be16_to_cpu(h.name_size);
129
130 if (sn->extra_data_size > QCOW_MAX_SNAPSHOT_EXTRA_DATA) {
131 if (!repair) {
132 ret = -EFBIG;
133 error_setg(errp, "Too much extra metadata in snapshot table "
134 "entry %i", i);
135 error_append_hint(errp, "You can force-remove this extra "
136 "metadata with qemu-img check -r all\n");
137 goto fail;
138 }
139
140 fprintf(stderr, "Discarding too much extra metadata in snapshot "
141 "table entry %i (%" PRIu32 " > %u)\n",
142 i, sn->extra_data_size, QCOW_MAX_SNAPSHOT_EXTRA_DATA);
143
144 (*extra_data_dropped)++;
145 truncate_unknown_extra_data = true;
146 }
147
148
149 ret = bdrv_pread(bs->file, offset, &extra,
150 MIN(sizeof(extra), sn->extra_data_size));
151 if (ret < 0) {
152 error_setg_errno(errp, -ret, "Failed to read snapshot table");
153 goto fail;
154 }
155 offset += MIN(sizeof(extra), sn->extra_data_size);
156
157 if (sn->extra_data_size >= endof(QCowSnapshotExtraData,
158 vm_state_size_large)) {
159 sn->vm_state_size = be64_to_cpu(extra.vm_state_size_large);
160 }
161
162 if (sn->extra_data_size >= endof(QCowSnapshotExtraData, disk_size)) {
163 sn->disk_size = be64_to_cpu(extra.disk_size);
164 } else {
165 sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
166 }
167
168 if (sn->extra_data_size >= endof(QCowSnapshotExtraData, icount)) {
169 sn->icount = be64_to_cpu(extra.icount);
170 } else {
171 sn->icount = -1ULL;
172 }
173
174 if (sn->extra_data_size > sizeof(extra)) {
175 uint64_t extra_data_end;
176 size_t unknown_extra_data_size;
177
178 extra_data_end = offset + sn->extra_data_size - sizeof(extra);
179
180 if (truncate_unknown_extra_data) {
181 sn->extra_data_size = QCOW_MAX_SNAPSHOT_EXTRA_DATA;
182 }
183
184
185 unknown_extra_data_size = sn->extra_data_size - sizeof(extra);
186 sn->unknown_extra_data = g_malloc(unknown_extra_data_size);
187 ret = bdrv_pread(bs->file, offset, sn->unknown_extra_data,
188 unknown_extra_data_size);
189 if (ret < 0) {
190 error_setg_errno(errp, -ret,
191 "Failed to read snapshot table");
192 goto fail;
193 }
194 offset = extra_data_end;
195 }
196
197
198 sn->id_str = g_malloc(id_str_size + 1);
199 ret = bdrv_pread(bs->file, offset, sn->id_str, id_str_size);
200 if (ret < 0) {
201 error_setg_errno(errp, -ret, "Failed to read snapshot table");
202 goto fail;
203 }
204 offset += id_str_size;
205 sn->id_str[id_str_size] = '\0';
206
207
208 sn->name = g_malloc(name_size + 1);
209 ret = bdrv_pread(bs->file, offset, sn->name, name_size);
210 if (ret < 0) {
211 error_setg_errno(errp, -ret, "Failed to read snapshot table");
212 goto fail;
213 }
214 offset += name_size;
215 sn->name[name_size] = '\0';
216
217
218 table_length += sizeof(h) + sn->extra_data_size + id_str_size +
219 name_size;
220 if (!repair) {
221 assert(table_length == offset - s->snapshots_offset);
222 }
223
224 if (table_length > QCOW_MAX_SNAPSHOTS_SIZE ||
225 offset - s->snapshots_offset > INT_MAX)
226 {
227 if (!repair) {
228 ret = -EFBIG;
229 error_setg(errp, "Snapshot table is too big");
230 error_append_hint(errp, "You can force-remove all %u "
231 "overhanging snapshots with qemu-img check "
232 "-r all\n", s->nb_snapshots - i);
233 goto fail;
234 }
235
236 fprintf(stderr, "Discarding %u overhanging snapshots (snapshot "
237 "table is too big)\n", s->nb_snapshots - i);
238
239 *nb_clusters_reduced += (s->nb_snapshots - i);
240
241
242 qcow2_free_single_snapshot(bs, i);
243
244
245
246
247
248
249 s->nb_snapshots = i;
250 offset = pre_sn_offset;
251 break;
252 }
253 }
254
255 assert(offset - s->snapshots_offset <= INT_MAX);
256 s->snapshots_size = offset - s->snapshots_offset;
257 return 0;
258
259fail:
260 qcow2_free_snapshots(bs);
261 return ret;
262}
263
264int qcow2_read_snapshots(BlockDriverState *bs, Error **errp)
265{
266 return qcow2_do_read_snapshots(bs, false, NULL, NULL, errp);
267}
268
269
270int qcow2_write_snapshots(BlockDriverState *bs)
271{
272 BDRVQcow2State *s = bs->opaque;
273 QCowSnapshot *sn;
274 QCowSnapshotHeader h;
275 QCowSnapshotExtraData extra;
276 int i, name_size, id_str_size, snapshots_size;
277 struct {
278 uint32_t nb_snapshots;
279 uint64_t snapshots_offset;
280 } QEMU_PACKED header_data;
281 int64_t offset, snapshots_offset = 0;
282 int ret;
283
284
285 offset = 0;
286 for(i = 0; i < s->nb_snapshots; i++) {
287 sn = s->snapshots + i;
288 offset = ROUND_UP(offset, 8);
289 offset += sizeof(h);
290 offset += MAX(sizeof(extra), sn->extra_data_size);
291 offset += strlen(sn->id_str);
292 offset += strlen(sn->name);
293
294 if (offset > QCOW_MAX_SNAPSHOTS_SIZE) {
295 ret = -EFBIG;
296 goto fail;
297 }
298 }
299
300 assert(offset <= INT_MAX);
301 snapshots_size = offset;
302
303
304 snapshots_offset = qcow2_alloc_clusters(bs, snapshots_size);
305 offset = snapshots_offset;
306 if (offset < 0) {
307 ret = offset;
308 goto fail;
309 }
310 ret = bdrv_flush(bs);
311 if (ret < 0) {
312 goto fail;
313 }
314
315
316
317 ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size, false);
318 if (ret < 0) {
319 goto fail;
320 }
321
322
323
324 for(i = 0; i < s->nb_snapshots; i++) {
325 sn = s->snapshots + i;
326 memset(&h, 0, sizeof(h));
327 h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
328 h.l1_size = cpu_to_be32(sn->l1_size);
329
330
331 if (sn->vm_state_size <= 0xffffffff) {
332 h.vm_state_size = cpu_to_be32(sn->vm_state_size);
333 }
334 h.date_sec = cpu_to_be32(sn->date_sec);
335 h.date_nsec = cpu_to_be32(sn->date_nsec);
336 h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
337 h.extra_data_size = cpu_to_be32(MAX(sizeof(extra),
338 sn->extra_data_size));
339
340 memset(&extra, 0, sizeof(extra));
341 extra.vm_state_size_large = cpu_to_be64(sn->vm_state_size);
342 extra.disk_size = cpu_to_be64(sn->disk_size);
343 extra.icount = cpu_to_be64(sn->icount);
344
345 id_str_size = strlen(sn->id_str);
346 name_size = strlen(sn->name);
347 assert(id_str_size <= UINT16_MAX && name_size <= UINT16_MAX);
348 h.id_str_size = cpu_to_be16(id_str_size);
349 h.name_size = cpu_to_be16(name_size);
350 offset = ROUND_UP(offset, 8);
351
352 ret = bdrv_pwrite(bs->file, offset, &h, sizeof(h));
353 if (ret < 0) {
354 goto fail;
355 }
356 offset += sizeof(h);
357
358 ret = bdrv_pwrite(bs->file, offset, &extra, sizeof(extra));
359 if (ret < 0) {
360 goto fail;
361 }
362 offset += sizeof(extra);
363
364 if (sn->extra_data_size > sizeof(extra)) {
365 size_t unknown_extra_data_size =
366 sn->extra_data_size - sizeof(extra);
367
368
369 assert(unknown_extra_data_size <= BDRV_REQUEST_MAX_BYTES);
370 assert(sn->unknown_extra_data);
371
372 ret = bdrv_pwrite(bs->file, offset, sn->unknown_extra_data,
373 unknown_extra_data_size);
374 if (ret < 0) {
375 goto fail;
376 }
377 offset += unknown_extra_data_size;
378 }
379
380 ret = bdrv_pwrite(bs->file, offset, sn->id_str, id_str_size);
381 if (ret < 0) {
382 goto fail;
383 }
384 offset += id_str_size;
385
386 ret = bdrv_pwrite(bs->file, offset, sn->name, name_size);
387 if (ret < 0) {
388 goto fail;
389 }
390 offset += name_size;
391 }
392
393
394
395
396
397 ret = bdrv_flush(bs);
398 if (ret < 0) {
399 goto fail;
400 }
401
402 QEMU_BUILD_BUG_ON(offsetof(QCowHeader, snapshots_offset) !=
403 endof(QCowHeader, nb_snapshots));
404
405 header_data.nb_snapshots = cpu_to_be32(s->nb_snapshots);
406 header_data.snapshots_offset = cpu_to_be64(snapshots_offset);
407
408 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
409 &header_data, sizeof(header_data));
410 if (ret < 0) {
411 goto fail;
412 }
413
414
415 qcow2_free_clusters(bs, s->snapshots_offset, s->snapshots_size,
416 QCOW2_DISCARD_SNAPSHOT);
417 s->snapshots_offset = snapshots_offset;
418 s->snapshots_size = snapshots_size;
419 return 0;
420
421fail:
422 if (snapshots_offset > 0) {
423 qcow2_free_clusters(bs, snapshots_offset, snapshots_size,
424 QCOW2_DISCARD_ALWAYS);
425 }
426 return ret;
427}
428
429int coroutine_fn qcow2_check_read_snapshot_table(BlockDriverState *bs,
430 BdrvCheckResult *result,
431 BdrvCheckMode fix)
432{
433 BDRVQcow2State *s = bs->opaque;
434 Error *local_err = NULL;
435 int nb_clusters_reduced = 0;
436 int extra_data_dropped = 0;
437 int ret;
438 struct {
439 uint32_t nb_snapshots;
440 uint64_t snapshots_offset;
441 } QEMU_PACKED snapshot_table_pointer;
442
443
444 ret = bdrv_pread(bs->file, offsetof(QCowHeader, nb_snapshots),
445 &snapshot_table_pointer, sizeof(snapshot_table_pointer));
446 if (ret < 0) {
447 result->check_errors++;
448 fprintf(stderr, "ERROR failed to read the snapshot table pointer from "
449 "the image header: %s\n", strerror(-ret));
450 return ret;
451 }
452
453 s->snapshots_offset = be64_to_cpu(snapshot_table_pointer.snapshots_offset);
454 s->nb_snapshots = be32_to_cpu(snapshot_table_pointer.nb_snapshots);
455
456 if (s->nb_snapshots > QCOW_MAX_SNAPSHOTS && (fix & BDRV_FIX_ERRORS)) {
457 fprintf(stderr, "Discarding %u overhanging snapshots\n",
458 s->nb_snapshots - QCOW_MAX_SNAPSHOTS);
459
460 nb_clusters_reduced += s->nb_snapshots - QCOW_MAX_SNAPSHOTS;
461 s->nb_snapshots = QCOW_MAX_SNAPSHOTS;
462 }
463
464 ret = qcow2_validate_table(bs, s->snapshots_offset, s->nb_snapshots,
465 sizeof(QCowSnapshotHeader),
466 sizeof(QCowSnapshotHeader) * QCOW_MAX_SNAPSHOTS,
467 "snapshot table", &local_err);
468 if (ret < 0) {
469 result->check_errors++;
470 error_reportf_err(local_err, "ERROR ");
471
472 if (s->nb_snapshots > QCOW_MAX_SNAPSHOTS) {
473 fprintf(stderr, "You can force-remove all %u overhanging snapshots "
474 "with qemu-img check -r all\n",
475 s->nb_snapshots - QCOW_MAX_SNAPSHOTS);
476 }
477
478
479 s->snapshots_offset = 0;
480 s->nb_snapshots = 0;
481
482 return ret;
483 }
484
485 qemu_co_mutex_unlock(&s->lock);
486 ret = qcow2_do_read_snapshots(bs, fix & BDRV_FIX_ERRORS,
487 &nb_clusters_reduced, &extra_data_dropped,
488 &local_err);
489 qemu_co_mutex_lock(&s->lock);
490 if (ret < 0) {
491 result->check_errors++;
492 error_reportf_err(local_err,
493 "ERROR failed to read the snapshot table: ");
494
495
496 s->snapshots_offset = 0;
497 s->nb_snapshots = 0;
498
499 return ret;
500 }
501 result->corruptions += nb_clusters_reduced + extra_data_dropped;
502
503 if (nb_clusters_reduced) {
504
505
506
507
508
509
510
511 assert(fix & BDRV_FIX_ERRORS);
512
513 snapshot_table_pointer.nb_snapshots = cpu_to_be32(s->nb_snapshots);
514 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
515 &snapshot_table_pointer.nb_snapshots,
516 sizeof(snapshot_table_pointer.nb_snapshots));
517 if (ret < 0) {
518 result->check_errors++;
519 fprintf(stderr, "ERROR failed to update the snapshot count in the "
520 "image header: %s\n", strerror(-ret));
521 return ret;
522 }
523
524 result->corruptions_fixed += nb_clusters_reduced;
525 result->corruptions -= nb_clusters_reduced;
526 }
527
528
529
530
531
532 if (s->qcow_version >= 3) {
533 int i;
534 for (i = 0; i < s->nb_snapshots; i++) {
535 if (s->snapshots[i].extra_data_size <
536 sizeof_field(QCowSnapshotExtraData, vm_state_size_large) +
537 sizeof_field(QCowSnapshotExtraData, disk_size))
538 {
539 result->corruptions++;
540 fprintf(stderr, "%s snapshot table entry %i is incomplete\n",
541 fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
542 }
543 }
544 }
545
546 return 0;
547}
548
549int coroutine_fn qcow2_check_fix_snapshot_table(BlockDriverState *bs,
550 BdrvCheckResult *result,
551 BdrvCheckMode fix)
552{
553 BDRVQcow2State *s = bs->opaque;
554 int ret;
555
556 if (result->corruptions && (fix & BDRV_FIX_ERRORS)) {
557 qemu_co_mutex_unlock(&s->lock);
558 ret = qcow2_write_snapshots(bs);
559 qemu_co_mutex_lock(&s->lock);
560 if (ret < 0) {
561 result->check_errors++;
562 fprintf(stderr, "ERROR failed to update snapshot table: %s\n",
563 strerror(-ret));
564 return ret;
565 }
566
567 result->corruptions_fixed += result->corruptions;
568 result->corruptions = 0;
569 }
570
571 return 0;
572}
573
574static void find_new_snapshot_id(BlockDriverState *bs,
575 char *id_str, int id_str_size)
576{
577 BDRVQcow2State *s = bs->opaque;
578 QCowSnapshot *sn;
579 int i;
580 unsigned long id, id_max = 0;
581
582 for(i = 0; i < s->nb_snapshots; i++) {
583 sn = s->snapshots + i;
584 id = strtoul(sn->id_str, NULL, 10);
585 if (id > id_max)
586 id_max = id;
587 }
588 snprintf(id_str, id_str_size, "%lu", id_max + 1);
589}
590
591static int find_snapshot_by_id_and_name(BlockDriverState *bs,
592 const char *id,
593 const char *name)
594{
595 BDRVQcow2State *s = bs->opaque;
596 int i;
597
598 if (id && name) {
599 for (i = 0; i < s->nb_snapshots; i++) {
600 if (!strcmp(s->snapshots[i].id_str, id) &&
601 !strcmp(s->snapshots[i].name, name)) {
602 return i;
603 }
604 }
605 } else if (id) {
606 for (i = 0; i < s->nb_snapshots; i++) {
607 if (!strcmp(s->snapshots[i].id_str, id)) {
608 return i;
609 }
610 }
611 } else if (name) {
612 for (i = 0; i < s->nb_snapshots; i++) {
613 if (!strcmp(s->snapshots[i].name, name)) {
614 return i;
615 }
616 }
617 }
618
619 return -1;
620}
621
622static int find_snapshot_by_id_or_name(BlockDriverState *bs,
623 const char *id_or_name)
624{
625 int ret;
626
627 ret = find_snapshot_by_id_and_name(bs, id_or_name, NULL);
628 if (ret >= 0) {
629 return ret;
630 }
631 return find_snapshot_by_id_and_name(bs, NULL, id_or_name);
632}
633
634
635int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
636{
637 BDRVQcow2State *s = bs->opaque;
638 QCowSnapshot *new_snapshot_list = NULL;
639 QCowSnapshot *old_snapshot_list = NULL;
640 QCowSnapshot sn1, *sn = &sn1;
641 int i, ret;
642 uint64_t *l1_table = NULL;
643 int64_t l1_table_offset;
644
645 if (s->nb_snapshots >= QCOW_MAX_SNAPSHOTS) {
646 return -EFBIG;
647 }
648
649 if (has_data_file(bs)) {
650 return -ENOTSUP;
651 }
652
653 memset(sn, 0, sizeof(*sn));
654
655
656 find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
657
658
659 sn->id_str = g_strdup(sn_info->id_str);
660 sn->name = g_strdup(sn_info->name);
661
662 sn->disk_size = bs->total_sectors * BDRV_SECTOR_SIZE;
663 sn->vm_state_size = sn_info->vm_state_size;
664 sn->date_sec = sn_info->date_sec;
665 sn->date_nsec = sn_info->date_nsec;
666 sn->vm_clock_nsec = sn_info->vm_clock_nsec;
667 sn->icount = sn_info->icount;
668 sn->extra_data_size = sizeof(QCowSnapshotExtraData);
669
670
671 l1_table_offset = qcow2_alloc_clusters(bs, s->l1_size * L1E_SIZE);
672 if (l1_table_offset < 0) {
673 ret = l1_table_offset;
674 goto fail;
675 }
676
677 sn->l1_table_offset = l1_table_offset;
678 sn->l1_size = s->l1_size;
679
680 l1_table = g_try_new(uint64_t, s->l1_size);
681 if (s->l1_size && l1_table == NULL) {
682 ret = -ENOMEM;
683 goto fail;
684 }
685
686 for(i = 0; i < s->l1_size; i++) {
687 l1_table[i] = cpu_to_be64(s->l1_table[i]);
688 }
689
690 ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
691 s->l1_size * L1E_SIZE, false);
692 if (ret < 0) {
693 goto fail;
694 }
695
696 ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
697 s->l1_size * L1E_SIZE);
698 if (ret < 0) {
699 goto fail;
700 }
701
702 g_free(l1_table);
703 l1_table = NULL;
704
705
706
707
708
709
710 ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
711 if (ret < 0) {
712 goto fail;
713 }
714
715
716 new_snapshot_list = g_new(QCowSnapshot, s->nb_snapshots + 1);
717 if (s->snapshots) {
718 memcpy(new_snapshot_list, s->snapshots,
719 s->nb_snapshots * sizeof(QCowSnapshot));
720 old_snapshot_list = s->snapshots;
721 }
722 s->snapshots = new_snapshot_list;
723 s->snapshots[s->nb_snapshots++] = *sn;
724
725 ret = qcow2_write_snapshots(bs);
726 if (ret < 0) {
727 g_free(s->snapshots);
728 s->snapshots = old_snapshot_list;
729 s->nb_snapshots--;
730 goto fail;
731 }
732
733 g_free(old_snapshot_list);
734
735
736
737 qcow2_cluster_discard(bs, qcow2_vm_state_offset(s),
738 ROUND_UP(sn->vm_state_size, s->cluster_size),
739 QCOW2_DISCARD_NEVER, false);
740
741#ifdef DEBUG_ALLOC
742 {
743 BdrvCheckResult result = {0};
744 qcow2_check_refcounts(bs, &result, 0);
745 }
746#endif
747 return 0;
748
749fail:
750 g_free(sn->id_str);
751 g_free(sn->name);
752 g_free(l1_table);
753
754 return ret;
755}
756
757
758int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
759{
760 BDRVQcow2State *s = bs->opaque;
761 QCowSnapshot *sn;
762 Error *local_err = NULL;
763 int i, snapshot_index;
764 int cur_l1_bytes, sn_l1_bytes;
765 int ret;
766 uint64_t *sn_l1_table = NULL;
767
768 if (has_data_file(bs)) {
769 return -ENOTSUP;
770 }
771
772
773 snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
774 if (snapshot_index < 0) {
775 return -ENOENT;
776 }
777 sn = &s->snapshots[snapshot_index];
778
779 ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
780 L1E_SIZE, QCOW_MAX_L1_SIZE,
781 "Snapshot L1 table", &local_err);
782 if (ret < 0) {
783 error_report_err(local_err);
784 goto fail;
785 }
786
787 if (sn->disk_size != bs->total_sectors * BDRV_SECTOR_SIZE) {
788 BlockBackend *blk = blk_new_with_bs(bs, BLK_PERM_RESIZE, BLK_PERM_ALL,
789 &local_err);
790 if (!blk) {
791 error_report_err(local_err);
792 ret = -ENOTSUP;
793 goto fail;
794 }
795
796 ret = blk_truncate(blk, sn->disk_size, true, PREALLOC_MODE_OFF, 0,
797 &local_err);
798 blk_unref(blk);
799 if (ret < 0) {
800 error_report_err(local_err);
801 goto fail;
802 }
803 }
804
805
806
807
808
809
810 ret = qcow2_grow_l1_table(bs, sn->l1_size, true);
811 if (ret < 0) {
812 goto fail;
813 }
814
815 cur_l1_bytes = s->l1_size * L1E_SIZE;
816 sn_l1_bytes = sn->l1_size * L1E_SIZE;
817
818
819
820
821
822
823
824
825
826 sn_l1_table = g_try_malloc0(cur_l1_bytes);
827 if (cur_l1_bytes && sn_l1_table == NULL) {
828 ret = -ENOMEM;
829 goto fail;
830 }
831
832 ret = bdrv_pread(bs->file, sn->l1_table_offset,
833 sn_l1_table, sn_l1_bytes);
834 if (ret < 0) {
835 goto fail;
836 }
837
838 ret = qcow2_update_snapshot_refcount(bs, sn->l1_table_offset,
839 sn->l1_size, 1);
840 if (ret < 0) {
841 goto fail;
842 }
843
844 ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
845 s->l1_table_offset, cur_l1_bytes,
846 false);
847 if (ret < 0) {
848 goto fail;
849 }
850
851 ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table,
852 cur_l1_bytes);
853 if (ret < 0) {
854 goto fail;
855 }
856
857
858
859
860
861
862
863
864
865
866
867 ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset,
868 s->l1_size, -1);
869
870
871
872
873
874 for(i = 0;i < s->l1_size; i++) {
875 s->l1_table[i] = be64_to_cpu(sn_l1_table[i]);
876 }
877
878 if (ret < 0) {
879 goto fail;
880 }
881
882 g_free(sn_l1_table);
883 sn_l1_table = NULL;
884
885
886
887
888
889 ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
890 if (ret < 0) {
891 goto fail;
892 }
893
894#ifdef DEBUG_ALLOC
895 {
896 BdrvCheckResult result = {0};
897 qcow2_check_refcounts(bs, &result, 0);
898 }
899#endif
900 return 0;
901
902fail:
903 g_free(sn_l1_table);
904 return ret;
905}
906
907int qcow2_snapshot_delete(BlockDriverState *bs,
908 const char *snapshot_id,
909 const char *name,
910 Error **errp)
911{
912 BDRVQcow2State *s = bs->opaque;
913 QCowSnapshot sn;
914 int snapshot_index, ret;
915
916 if (has_data_file(bs)) {
917 return -ENOTSUP;
918 }
919
920
921 snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
922 if (snapshot_index < 0) {
923 error_setg(errp, "Can't find the snapshot");
924 return -ENOENT;
925 }
926 sn = s->snapshots[snapshot_index];
927
928 ret = qcow2_validate_table(bs, sn.l1_table_offset, sn.l1_size,
929 L1E_SIZE, QCOW_MAX_L1_SIZE,
930 "Snapshot L1 table", errp);
931 if (ret < 0) {
932 return ret;
933 }
934
935
936 memmove(s->snapshots + snapshot_index,
937 s->snapshots + snapshot_index + 1,
938 (s->nb_snapshots - snapshot_index - 1) * sizeof(sn));
939 s->nb_snapshots--;
940 ret = qcow2_write_snapshots(bs);
941 if (ret < 0) {
942 error_setg_errno(errp, -ret,
943 "Failed to remove snapshot from snapshot list");
944 return ret;
945 }
946
947
948
949
950
951 g_free(sn.unknown_extra_data);
952 g_free(sn.id_str);
953 g_free(sn.name);
954
955
956
957
958
959 ret = qcow2_update_snapshot_refcount(bs, sn.l1_table_offset,
960 sn.l1_size, -1);
961 if (ret < 0) {
962 error_setg_errno(errp, -ret, "Failed to free the cluster and L1 table");
963 return ret;
964 }
965 qcow2_free_clusters(bs, sn.l1_table_offset, sn.l1_size * L1E_SIZE,
966 QCOW2_DISCARD_SNAPSHOT);
967
968
969 ret = qcow2_update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
970 if (ret < 0) {
971 error_setg_errno(errp, -ret,
972 "Failed to update snapshot status in disk");
973 return ret;
974 }
975
976#ifdef DEBUG_ALLOC
977 {
978 BdrvCheckResult result = {0};
979 qcow2_check_refcounts(bs, &result, 0);
980 }
981#endif
982 return 0;
983}
984
985int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
986{
987 BDRVQcow2State *s = bs->opaque;
988 QEMUSnapshotInfo *sn_tab, *sn_info;
989 QCowSnapshot *sn;
990 int i;
991
992 if (has_data_file(bs)) {
993 return -ENOTSUP;
994 }
995 if (!s->nb_snapshots) {
996 *psn_tab = NULL;
997 return s->nb_snapshots;
998 }
999
1000 sn_tab = g_new0(QEMUSnapshotInfo, s->nb_snapshots);
1001 for(i = 0; i < s->nb_snapshots; i++) {
1002 sn_info = sn_tab + i;
1003 sn = s->snapshots + i;
1004 pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
1005 sn->id_str);
1006 pstrcpy(sn_info->name, sizeof(sn_info->name),
1007 sn->name);
1008 sn_info->vm_state_size = sn->vm_state_size;
1009 sn_info->date_sec = sn->date_sec;
1010 sn_info->date_nsec = sn->date_nsec;
1011 sn_info->vm_clock_nsec = sn->vm_clock_nsec;
1012 sn_info->icount = sn->icount;
1013 }
1014 *psn_tab = sn_tab;
1015 return s->nb_snapshots;
1016}
1017
1018int qcow2_snapshot_load_tmp(BlockDriverState *bs,
1019 const char *snapshot_id,
1020 const char *name,
1021 Error **errp)
1022{
1023 int i, snapshot_index;
1024 BDRVQcow2State *s = bs->opaque;
1025 QCowSnapshot *sn;
1026 uint64_t *new_l1_table;
1027 int new_l1_bytes;
1028 int ret;
1029
1030 assert(bdrv_is_read_only(bs));
1031
1032
1033 snapshot_index = find_snapshot_by_id_and_name(bs, snapshot_id, name);
1034 if (snapshot_index < 0) {
1035 error_setg(errp,
1036 "Can't find snapshot");
1037 return -ENOENT;
1038 }
1039 sn = &s->snapshots[snapshot_index];
1040
1041
1042 ret = qcow2_validate_table(bs, sn->l1_table_offset, sn->l1_size,
1043 L1E_SIZE, QCOW_MAX_L1_SIZE,
1044 "Snapshot L1 table", errp);
1045 if (ret < 0) {
1046 return ret;
1047 }
1048 new_l1_bytes = sn->l1_size * L1E_SIZE;
1049 new_l1_table = qemu_try_blockalign(bs->file->bs, new_l1_bytes);
1050 if (new_l1_table == NULL) {
1051 return -ENOMEM;
1052 }
1053
1054 ret = bdrv_pread(bs->file, sn->l1_table_offset,
1055 new_l1_table, new_l1_bytes);
1056 if (ret < 0) {
1057 error_setg(errp, "Failed to read l1 table for snapshot");
1058 qemu_vfree(new_l1_table);
1059 return ret;
1060 }
1061
1062
1063 qemu_vfree(s->l1_table);
1064
1065 s->l1_size = sn->l1_size;
1066 s->l1_table_offset = sn->l1_table_offset;
1067 s->l1_table = new_l1_table;
1068
1069 for(i = 0;i < s->l1_size; i++) {
1070 be64_to_cpus(&s->l1_table[i]);
1071 }
1072
1073 return 0;
1074}
1075