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25#include "qemu/osdep.h"
26#include <zlib.h>
27
28#include "qapi/error.h"
29#include "qemu-common.h"
30#include "block/block_int.h"
31#include "qcow2.h"
32#include "qemu/bswap.h"
33#include "trace.h"
34
35int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t exact_size)
36{
37 BDRVQcow2State *s = bs->opaque;
38 int new_l1_size, i, ret;
39
40 if (exact_size >= s->l1_size) {
41 return 0;
42 }
43
44 new_l1_size = exact_size;
45
46#ifdef DEBUG_ALLOC2
47 fprintf(stderr, "shrink l1_table from %d to %d\n", s->l1_size, new_l1_size);
48#endif
49
50 BLKDBG_EVENT(bs->file, BLKDBG_L1_SHRINK_WRITE_TABLE);
51 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset +
52 new_l1_size * sizeof(uint64_t),
53 (s->l1_size - new_l1_size) * sizeof(uint64_t), 0);
54 if (ret < 0) {
55 goto fail;
56 }
57
58 ret = bdrv_flush(bs->file->bs);
59 if (ret < 0) {
60 goto fail;
61 }
62
63 BLKDBG_EVENT(bs->file, BLKDBG_L1_SHRINK_FREE_L2_CLUSTERS);
64 for (i = s->l1_size - 1; i > new_l1_size - 1; i--) {
65 if ((s->l1_table[i] & L1E_OFFSET_MASK) == 0) {
66 continue;
67 }
68 qcow2_free_clusters(bs, s->l1_table[i] & L1E_OFFSET_MASK,
69 s->cluster_size, QCOW2_DISCARD_ALWAYS);
70 s->l1_table[i] = 0;
71 }
72 return 0;
73
74fail:
75
76
77
78
79
80 memset(s->l1_table + new_l1_size, 0,
81 (s->l1_size - new_l1_size) * sizeof(uint64_t));
82 return ret;
83}
84
85int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
86 bool exact_size)
87{
88 BDRVQcow2State *s = bs->opaque;
89 int new_l1_size2, ret, i;
90 uint64_t *new_l1_table;
91 int64_t old_l1_table_offset, old_l1_size;
92 int64_t new_l1_table_offset, new_l1_size;
93 uint8_t data[12];
94
95 if (min_size <= s->l1_size)
96 return 0;
97
98
99
100
101 if (min_size > INT_MAX / sizeof(uint64_t)) {
102 return -EFBIG;
103 }
104
105 if (exact_size) {
106 new_l1_size = min_size;
107 } else {
108
109 new_l1_size = s->l1_size;
110 if (new_l1_size == 0) {
111 new_l1_size = 1;
112 }
113 while (min_size > new_l1_size) {
114 new_l1_size = DIV_ROUND_UP(new_l1_size * 3, 2);
115 }
116 }
117
118 QEMU_BUILD_BUG_ON(QCOW_MAX_L1_SIZE > INT_MAX);
119 if (new_l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
120 return -EFBIG;
121 }
122
123#ifdef DEBUG_ALLOC2
124 fprintf(stderr, "grow l1_table from %d to %" PRId64 "\n",
125 s->l1_size, new_l1_size);
126#endif
127
128 new_l1_size2 = sizeof(uint64_t) * new_l1_size;
129 new_l1_table = qemu_try_blockalign(bs->file->bs,
130 ROUND_UP(new_l1_size2, 512));
131 if (new_l1_table == NULL) {
132 return -ENOMEM;
133 }
134 memset(new_l1_table, 0, ROUND_UP(new_l1_size2, 512));
135
136 if (s->l1_size) {
137 memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
138 }
139
140
141 BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
142 new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
143 if (new_l1_table_offset < 0) {
144 qemu_vfree(new_l1_table);
145 return new_l1_table_offset;
146 }
147
148 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
149 if (ret < 0) {
150 goto fail;
151 }
152
153
154
155 ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset,
156 new_l1_size2);
157 if (ret < 0) {
158 goto fail;
159 }
160
161 BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
162 for(i = 0; i < s->l1_size; i++)
163 new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
164 ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset,
165 new_l1_table, new_l1_size2);
166 if (ret < 0)
167 goto fail;
168 for(i = 0; i < s->l1_size; i++)
169 new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
170
171
172 BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE);
173 stl_be_p(data, new_l1_size);
174 stq_be_p(data + 4, new_l1_table_offset);
175 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size),
176 data, sizeof(data));
177 if (ret < 0) {
178 goto fail;
179 }
180 qemu_vfree(s->l1_table);
181 old_l1_table_offset = s->l1_table_offset;
182 s->l1_table_offset = new_l1_table_offset;
183 s->l1_table = new_l1_table;
184 old_l1_size = s->l1_size;
185 s->l1_size = new_l1_size;
186 qcow2_free_clusters(bs, old_l1_table_offset, old_l1_size * sizeof(uint64_t),
187 QCOW2_DISCARD_OTHER);
188 return 0;
189 fail:
190 qemu_vfree(new_l1_table);
191 qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2,
192 QCOW2_DISCARD_OTHER);
193 return ret;
194}
195
196
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208
209
210static int l2_load(BlockDriverState *bs, uint64_t offset,
211 uint64_t l2_offset, uint64_t **l2_slice)
212{
213 BDRVQcow2State *s = bs->opaque;
214 int start_of_slice = sizeof(uint64_t) *
215 (offset_to_l2_index(s, offset) - offset_to_l2_slice_index(s, offset));
216
217 return qcow2_cache_get(bs, s->l2_table_cache, l2_offset + start_of_slice,
218 (void **)l2_slice);
219}
220
221
222
223
224
225#define L1_ENTRIES_PER_SECTOR (512 / 8)
226int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
227{
228 BDRVQcow2State *s = bs->opaque;
229 uint64_t buf[L1_ENTRIES_PER_SECTOR] = { 0 };
230 int l1_start_index;
231 int i, ret;
232
233 l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
234 for (i = 0; i < L1_ENTRIES_PER_SECTOR && l1_start_index + i < s->l1_size;
235 i++)
236 {
237 buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
238 }
239
240 ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
241 s->l1_table_offset + 8 * l1_start_index, sizeof(buf));
242 if (ret < 0) {
243 return ret;
244 }
245
246 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
247 ret = bdrv_pwrite_sync(bs->file,
248 s->l1_table_offset + 8 * l1_start_index,
249 buf, sizeof(buf));
250 if (ret < 0) {
251 return ret;
252 }
253
254 return 0;
255}
256
257
258
259
260
261
262
263
264
265
266
267static int l2_allocate(BlockDriverState *bs, int l1_index)
268{
269 BDRVQcow2State *s = bs->opaque;
270 uint64_t old_l2_offset;
271 uint64_t *l2_slice = NULL;
272 unsigned slice, slice_size2, n_slices;
273 int64_t l2_offset;
274 int ret;
275
276 old_l2_offset = s->l1_table[l1_index];
277
278 trace_qcow2_l2_allocate(bs, l1_index);
279
280
281
282 l2_offset = qcow2_alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
283 if (l2_offset < 0) {
284 ret = l2_offset;
285 goto fail;
286 }
287
288
289 if (l2_offset == 0) {
290 qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid "
291 "allocation of L2 table at offset 0");
292 ret = -EIO;
293 goto fail;
294 }
295
296 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
297 if (ret < 0) {
298 goto fail;
299 }
300
301
302
303 slice_size2 = s->l2_slice_size * sizeof(uint64_t);
304 n_slices = s->cluster_size / slice_size2;
305
306 trace_qcow2_l2_allocate_get_empty(bs, l1_index);
307 for (slice = 0; slice < n_slices; slice++) {
308 ret = qcow2_cache_get_empty(bs, s->l2_table_cache,
309 l2_offset + slice * slice_size2,
310 (void **) &l2_slice);
311 if (ret < 0) {
312 goto fail;
313 }
314
315 if ((old_l2_offset & L1E_OFFSET_MASK) == 0) {
316
317 memset(l2_slice, 0, slice_size2);
318 } else {
319 uint64_t *old_slice;
320 uint64_t old_l2_slice_offset =
321 (old_l2_offset & L1E_OFFSET_MASK) + slice * slice_size2;
322
323
324 BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
325 ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_slice_offset,
326 (void **) &old_slice);
327 if (ret < 0) {
328 goto fail;
329 }
330
331 memcpy(l2_slice, old_slice, slice_size2);
332
333 qcow2_cache_put(s->l2_table_cache, (void **) &old_slice);
334 }
335
336
337 BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
338
339 trace_qcow2_l2_allocate_write_l2(bs, l1_index);
340 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
341 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
342 }
343
344 ret = qcow2_cache_flush(bs, s->l2_table_cache);
345 if (ret < 0) {
346 goto fail;
347 }
348
349
350 trace_qcow2_l2_allocate_write_l1(bs, l1_index);
351 s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
352 ret = qcow2_write_l1_entry(bs, l1_index);
353 if (ret < 0) {
354 goto fail;
355 }
356
357 trace_qcow2_l2_allocate_done(bs, l1_index, 0);
358 return 0;
359
360fail:
361 trace_qcow2_l2_allocate_done(bs, l1_index, ret);
362 if (l2_slice != NULL) {
363 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
364 }
365 s->l1_table[l1_index] = old_l2_offset;
366 if (l2_offset > 0) {
367 qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t),
368 QCOW2_DISCARD_ALWAYS);
369 }
370 return ret;
371}
372
373
374
375
376
377
378
379
380static int count_contiguous_clusters(int nb_clusters, int cluster_size,
381 uint64_t *l2_slice, uint64_t stop_flags)
382{
383 int i;
384 QCow2ClusterType first_cluster_type;
385 uint64_t mask = stop_flags | L2E_OFFSET_MASK | QCOW_OFLAG_COMPRESSED;
386 uint64_t first_entry = be64_to_cpu(l2_slice[0]);
387 uint64_t offset = first_entry & mask;
388
389 if (!offset) {
390 return 0;
391 }
392
393
394 first_cluster_type = qcow2_get_cluster_type(first_entry);
395 assert(first_cluster_type == QCOW2_CLUSTER_NORMAL ||
396 first_cluster_type == QCOW2_CLUSTER_ZERO_ALLOC);
397
398 for (i = 0; i < nb_clusters; i++) {
399 uint64_t l2_entry = be64_to_cpu(l2_slice[i]) & mask;
400 if (offset + (uint64_t) i * cluster_size != l2_entry) {
401 break;
402 }
403 }
404
405 return i;
406}
407
408
409
410
411
412static int count_contiguous_clusters_unallocated(int nb_clusters,
413 uint64_t *l2_slice,
414 QCow2ClusterType wanted_type)
415{
416 int i;
417
418 assert(wanted_type == QCOW2_CLUSTER_ZERO_PLAIN ||
419 wanted_type == QCOW2_CLUSTER_UNALLOCATED);
420 for (i = 0; i < nb_clusters; i++) {
421 uint64_t entry = be64_to_cpu(l2_slice[i]);
422 QCow2ClusterType type = qcow2_get_cluster_type(entry);
423
424 if (type != wanted_type) {
425 break;
426 }
427 }
428
429 return i;
430}
431
432static int coroutine_fn do_perform_cow_read(BlockDriverState *bs,
433 uint64_t src_cluster_offset,
434 unsigned offset_in_cluster,
435 QEMUIOVector *qiov)
436{
437 int ret;
438
439 if (qiov->size == 0) {
440 return 0;
441 }
442
443 BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
444
445 if (!bs->drv) {
446 return -ENOMEDIUM;
447 }
448
449
450
451
452
453 ret = bs->drv->bdrv_co_preadv(bs, src_cluster_offset + offset_in_cluster,
454 qiov->size, qiov, 0);
455 if (ret < 0) {
456 return ret;
457 }
458
459 return 0;
460}
461
462static bool coroutine_fn do_perform_cow_encrypt(BlockDriverState *bs,
463 uint64_t src_cluster_offset,
464 uint64_t cluster_offset,
465 unsigned offset_in_cluster,
466 uint8_t *buffer,
467 unsigned bytes)
468{
469 if (bytes && bs->encrypted) {
470 BDRVQcow2State *s = bs->opaque;
471 int64_t offset = (s->crypt_physical_offset ?
472 (cluster_offset + offset_in_cluster) :
473 (src_cluster_offset + offset_in_cluster));
474 assert((offset_in_cluster & ~BDRV_SECTOR_MASK) == 0);
475 assert((bytes & ~BDRV_SECTOR_MASK) == 0);
476 assert(s->crypto);
477 if (qcrypto_block_encrypt(s->crypto, offset, buffer, bytes, NULL) < 0) {
478 return false;
479 }
480 }
481 return true;
482}
483
484static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,
485 uint64_t cluster_offset,
486 unsigned offset_in_cluster,
487 QEMUIOVector *qiov)
488{
489 int ret;
490
491 if (qiov->size == 0) {
492 return 0;
493 }
494
495 ret = qcow2_pre_write_overlap_check(bs, 0,
496 cluster_offset + offset_in_cluster, qiov->size);
497 if (ret < 0) {
498 return ret;
499 }
500
501 BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
502 ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster,
503 qiov->size, qiov, 0);
504 if (ret < 0) {
505 return ret;
506 }
507
508 return 0;
509}
510
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526
527
528int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
529 unsigned int *bytes, uint64_t *cluster_offset)
530{
531 BDRVQcow2State *s = bs->opaque;
532 unsigned int l2_index;
533 uint64_t l1_index, l2_offset, *l2_slice;
534 int c;
535 unsigned int offset_in_cluster;
536 uint64_t bytes_available, bytes_needed, nb_clusters;
537 QCow2ClusterType type;
538 int ret;
539
540 offset_in_cluster = offset_into_cluster(s, offset);
541 bytes_needed = (uint64_t) *bytes + offset_in_cluster;
542
543
544
545
546 bytes_available =
547 ((uint64_t) (s->l2_slice_size - offset_to_l2_slice_index(s, offset)))
548 << s->cluster_bits;
549
550 if (bytes_needed > bytes_available) {
551 bytes_needed = bytes_available;
552 }
553
554 *cluster_offset = 0;
555
556
557
558 l1_index = offset_to_l1_index(s, offset);
559 if (l1_index >= s->l1_size) {
560 type = QCOW2_CLUSTER_UNALLOCATED;
561 goto out;
562 }
563
564 l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
565 if (!l2_offset) {
566 type = QCOW2_CLUSTER_UNALLOCATED;
567 goto out;
568 }
569
570 if (offset_into_cluster(s, l2_offset)) {
571 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64
572 " unaligned (L1 index: %#" PRIx64 ")",
573 l2_offset, l1_index);
574 return -EIO;
575 }
576
577
578
579 ret = l2_load(bs, offset, l2_offset, &l2_slice);
580 if (ret < 0) {
581 return ret;
582 }
583
584
585
586 l2_index = offset_to_l2_slice_index(s, offset);
587 *cluster_offset = be64_to_cpu(l2_slice[l2_index]);
588
589 nb_clusters = size_to_clusters(s, bytes_needed);
590
591
592
593 assert(nb_clusters <= INT_MAX);
594
595 type = qcow2_get_cluster_type(*cluster_offset);
596 if (s->qcow_version < 3 && (type == QCOW2_CLUSTER_ZERO_PLAIN ||
597 type == QCOW2_CLUSTER_ZERO_ALLOC)) {
598 qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry found"
599 " in pre-v3 image (L2 offset: %#" PRIx64
600 ", L2 index: %#x)", l2_offset, l2_index);
601 ret = -EIO;
602 goto fail;
603 }
604 switch (type) {
605 case QCOW2_CLUSTER_COMPRESSED:
606
607 c = 1;
608 *cluster_offset &= L2E_COMPRESSED_OFFSET_SIZE_MASK;
609 break;
610 case QCOW2_CLUSTER_ZERO_PLAIN:
611 case QCOW2_CLUSTER_UNALLOCATED:
612
613 c = count_contiguous_clusters_unallocated(nb_clusters,
614 &l2_slice[l2_index], type);
615 *cluster_offset = 0;
616 break;
617 case QCOW2_CLUSTER_ZERO_ALLOC:
618 case QCOW2_CLUSTER_NORMAL:
619
620 c = count_contiguous_clusters(nb_clusters, s->cluster_size,
621 &l2_slice[l2_index], QCOW_OFLAG_ZERO);
622 *cluster_offset &= L2E_OFFSET_MASK;
623 if (offset_into_cluster(s, *cluster_offset)) {
624 qcow2_signal_corruption(bs, true, -1, -1,
625 "Cluster allocation offset %#"
626 PRIx64 " unaligned (L2 offset: %#" PRIx64
627 ", L2 index: %#x)", *cluster_offset,
628 l2_offset, l2_index);
629 ret = -EIO;
630 goto fail;
631 }
632 break;
633 default:
634 abort();
635 }
636
637 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
638
639 bytes_available = (int64_t)c * s->cluster_size;
640
641out:
642 if (bytes_available > bytes_needed) {
643 bytes_available = bytes_needed;
644 }
645
646
647
648
649 assert(bytes_available - offset_in_cluster <= UINT_MAX);
650 *bytes = bytes_available - offset_in_cluster;
651
652 return type;
653
654fail:
655 qcow2_cache_put(s->l2_table_cache, (void **)&l2_slice);
656 return ret;
657}
658
659
660
661
662
663
664
665
666
667
668
669static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
670 uint64_t **new_l2_slice,
671 int *new_l2_index)
672{
673 BDRVQcow2State *s = bs->opaque;
674 unsigned int l2_index;
675 uint64_t l1_index, l2_offset;
676 uint64_t *l2_slice = NULL;
677 int ret;
678
679
680
681 l1_index = offset_to_l1_index(s, offset);
682 if (l1_index >= s->l1_size) {
683 ret = qcow2_grow_l1_table(bs, l1_index + 1, false);
684 if (ret < 0) {
685 return ret;
686 }
687 }
688
689 assert(l1_index < s->l1_size);
690 l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
691 if (offset_into_cluster(s, l2_offset)) {
692 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64
693 " unaligned (L1 index: %#" PRIx64 ")",
694 l2_offset, l1_index);
695 return -EIO;
696 }
697
698 if (!(s->l1_table[l1_index] & QCOW_OFLAG_COPIED)) {
699
700 ret = l2_allocate(bs, l1_index);
701 if (ret < 0) {
702 return ret;
703 }
704
705
706 if (l2_offset) {
707 qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t),
708 QCOW2_DISCARD_OTHER);
709 }
710
711
712 l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
713 assert(offset_into_cluster(s, l2_offset) == 0);
714 }
715
716
717 ret = l2_load(bs, offset, l2_offset, &l2_slice);
718 if (ret < 0) {
719 return ret;
720 }
721
722
723
724 l2_index = offset_to_l2_slice_index(s, offset);
725
726 *new_l2_slice = l2_slice;
727 *new_l2_index = l2_index;
728
729 return 0;
730}
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
746 uint64_t offset,
747 int compressed_size)
748{
749 BDRVQcow2State *s = bs->opaque;
750 int l2_index, ret;
751 uint64_t *l2_slice;
752 int64_t cluster_offset;
753 int nb_csectors;
754
755 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
756 if (ret < 0) {
757 return 0;
758 }
759
760
761
762 cluster_offset = be64_to_cpu(l2_slice[l2_index]);
763 if (cluster_offset & L2E_OFFSET_MASK) {
764 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
765 return 0;
766 }
767
768 cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
769 if (cluster_offset < 0) {
770 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
771 return 0;
772 }
773
774 nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
775 (cluster_offset >> 9);
776
777 cluster_offset |= QCOW_OFLAG_COMPRESSED |
778 ((uint64_t)nb_csectors << s->csize_shift);
779
780
781
782
783
784 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
785 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
786 l2_slice[l2_index] = cpu_to_be64(cluster_offset);
787 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
788
789 return cluster_offset;
790}
791
792static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
793{
794 BDRVQcow2State *s = bs->opaque;
795 Qcow2COWRegion *start = &m->cow_start;
796 Qcow2COWRegion *end = &m->cow_end;
797 unsigned buffer_size;
798 unsigned data_bytes = end->offset - (start->offset + start->nb_bytes);
799 bool merge_reads;
800 uint8_t *start_buffer, *end_buffer;
801 QEMUIOVector qiov;
802 int ret;
803
804 assert(start->nb_bytes <= UINT_MAX - end->nb_bytes);
805 assert(start->nb_bytes + end->nb_bytes <= UINT_MAX - data_bytes);
806 assert(start->offset + start->nb_bytes <= end->offset);
807 assert(!m->data_qiov || m->data_qiov->size == data_bytes);
808
809 if (start->nb_bytes == 0 && end->nb_bytes == 0) {
810 return 0;
811 }
812
813
814
815
816 merge_reads = start->nb_bytes && end->nb_bytes && data_bytes <= 16384;
817 if (merge_reads) {
818 buffer_size = start->nb_bytes + data_bytes + end->nb_bytes;
819 } else {
820
821
822
823 size_t align = bdrv_opt_mem_align(bs);
824 assert(align > 0 && align <= UINT_MAX);
825 assert(QEMU_ALIGN_UP(start->nb_bytes, align) <=
826 UINT_MAX - end->nb_bytes);
827 buffer_size = QEMU_ALIGN_UP(start->nb_bytes, align) + end->nb_bytes;
828 }
829
830
831
832 start_buffer = qemu_try_blockalign(bs, buffer_size);
833 if (start_buffer == NULL) {
834 return -ENOMEM;
835 }
836
837 end_buffer = start_buffer + buffer_size - end->nb_bytes;
838
839 qemu_iovec_init(&qiov, 2 + (m->data_qiov ? m->data_qiov->niov : 0));
840
841 qemu_co_mutex_unlock(&s->lock);
842
843
844
845 if (merge_reads) {
846 qemu_iovec_add(&qiov, start_buffer, buffer_size);
847 ret = do_perform_cow_read(bs, m->offset, start->offset, &qiov);
848 } else {
849 qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
850 ret = do_perform_cow_read(bs, m->offset, start->offset, &qiov);
851 if (ret < 0) {
852 goto fail;
853 }
854
855 qemu_iovec_reset(&qiov);
856 qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
857 ret = do_perform_cow_read(bs, m->offset, end->offset, &qiov);
858 }
859 if (ret < 0) {
860 goto fail;
861 }
862
863
864 if (bs->encrypted) {
865 if (!do_perform_cow_encrypt(bs, m->offset, m->alloc_offset,
866 start->offset, start_buffer,
867 start->nb_bytes) ||
868 !do_perform_cow_encrypt(bs, m->offset, m->alloc_offset,
869 end->offset, end_buffer, end->nb_bytes)) {
870 ret = -EIO;
871 goto fail;
872 }
873 }
874
875
876
877 if (m->data_qiov) {
878 qemu_iovec_reset(&qiov);
879 if (start->nb_bytes) {
880 qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
881 }
882 qemu_iovec_concat(&qiov, m->data_qiov, 0, data_bytes);
883 if (end->nb_bytes) {
884 qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
885 }
886
887
888
889 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
890 ret = do_perform_cow_write(bs, m->alloc_offset, start->offset, &qiov);
891 } else {
892
893 qemu_iovec_reset(&qiov);
894 qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
895 ret = do_perform_cow_write(bs, m->alloc_offset, start->offset, &qiov);
896 if (ret < 0) {
897 goto fail;
898 }
899
900 qemu_iovec_reset(&qiov);
901 qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
902 ret = do_perform_cow_write(bs, m->alloc_offset, end->offset, &qiov);
903 }
904
905fail:
906 qemu_co_mutex_lock(&s->lock);
907
908
909
910
911
912
913 if (ret == 0) {
914 qcow2_cache_depends_on_flush(s->l2_table_cache);
915 }
916
917 qemu_vfree(start_buffer);
918 qemu_iovec_destroy(&qiov);
919 return ret;
920}
921
922int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
923{
924 BDRVQcow2State *s = bs->opaque;
925 int i, j = 0, l2_index, ret;
926 uint64_t *old_cluster, *l2_slice;
927 uint64_t cluster_offset = m->alloc_offset;
928
929 trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
930 assert(m->nb_clusters > 0);
931
932 old_cluster = g_try_new(uint64_t, m->nb_clusters);
933 if (old_cluster == NULL) {
934 ret = -ENOMEM;
935 goto err;
936 }
937
938
939 ret = perform_cow(bs, m);
940 if (ret < 0) {
941 goto err;
942 }
943
944
945 if (s->use_lazy_refcounts) {
946 qcow2_mark_dirty(bs);
947 }
948 if (qcow2_need_accurate_refcounts(s)) {
949 qcow2_cache_set_dependency(bs, s->l2_table_cache,
950 s->refcount_block_cache);
951 }
952
953 ret = get_cluster_table(bs, m->offset, &l2_slice, &l2_index);
954 if (ret < 0) {
955 goto err;
956 }
957 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
958
959 assert(l2_index + m->nb_clusters <= s->l2_slice_size);
960 for (i = 0; i < m->nb_clusters; i++) {
961
962
963
964
965
966
967 if (l2_slice[l2_index + i] != 0) {
968 old_cluster[j++] = l2_slice[l2_index + i];
969 }
970
971 l2_slice[l2_index + i] = cpu_to_be64((cluster_offset +
972 (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
973 }
974
975
976 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
977
978
979
980
981
982
983
984 if (!m->keep_old_clusters && j != 0) {
985 for (i = 0; i < j; i++) {
986 qcow2_free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1,
987 QCOW2_DISCARD_NEVER);
988 }
989 }
990
991 ret = 0;
992err:
993 g_free(old_cluster);
994 return ret;
995 }
996
997
998
999
1000
1001void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m)
1002{
1003 BDRVQcow2State *s = bs->opaque;
1004 qcow2_free_clusters(bs, m->alloc_offset, m->nb_clusters << s->cluster_bits,
1005 QCOW2_DISCARD_NEVER);
1006}
1007
1008
1009
1010
1011
1012
1013static int count_cow_clusters(BDRVQcow2State *s, int nb_clusters,
1014 uint64_t *l2_slice, int l2_index)
1015{
1016 int i;
1017
1018 for (i = 0; i < nb_clusters; i++) {
1019 uint64_t l2_entry = be64_to_cpu(l2_slice[l2_index + i]);
1020 QCow2ClusterType cluster_type = qcow2_get_cluster_type(l2_entry);
1021
1022 switch(cluster_type) {
1023 case QCOW2_CLUSTER_NORMAL:
1024 if (l2_entry & QCOW_OFLAG_COPIED) {
1025 goto out;
1026 }
1027 break;
1028 case QCOW2_CLUSTER_UNALLOCATED:
1029 case QCOW2_CLUSTER_COMPRESSED:
1030 case QCOW2_CLUSTER_ZERO_PLAIN:
1031 case QCOW2_CLUSTER_ZERO_ALLOC:
1032 break;
1033 default:
1034 abort();
1035 }
1036 }
1037
1038out:
1039 assert(i <= nb_clusters);
1040 return i;
1041}
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
1058 uint64_t *cur_bytes, QCowL2Meta **m)
1059{
1060 BDRVQcow2State *s = bs->opaque;
1061 QCowL2Meta *old_alloc;
1062 uint64_t bytes = *cur_bytes;
1063
1064 QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
1065
1066 uint64_t start = guest_offset;
1067 uint64_t end = start + bytes;
1068 uint64_t old_start = l2meta_cow_start(old_alloc);
1069 uint64_t old_end = l2meta_cow_end(old_alloc);
1070
1071 if (end <= old_start || start >= old_end) {
1072
1073 } else {
1074 if (start < old_start) {
1075
1076 bytes = old_start - start;
1077 } else {
1078 bytes = 0;
1079 }
1080
1081
1082
1083
1084
1085 if (bytes == 0 && *m) {
1086 *cur_bytes = 0;
1087 return 0;
1088 }
1089
1090 if (bytes == 0) {
1091
1092
1093 qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock);
1094 return -EAGAIN;
1095 }
1096 }
1097 }
1098
1099
1100
1101 *cur_bytes = bytes;
1102
1103 return 0;
1104}
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
1129 uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
1130{
1131 BDRVQcow2State *s = bs->opaque;
1132 int l2_index;
1133 uint64_t cluster_offset;
1134 uint64_t *l2_slice;
1135 uint64_t nb_clusters;
1136 unsigned int keep_clusters;
1137 int ret;
1138
1139 trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset,
1140 *bytes);
1141
1142 assert(*host_offset == 0 || offset_into_cluster(s, guest_offset)
1143 == offset_into_cluster(s, *host_offset));
1144
1145
1146
1147
1148
1149 nb_clusters =
1150 size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
1151
1152 l2_index = offset_to_l2_slice_index(s, guest_offset);
1153 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1154 assert(nb_clusters <= INT_MAX);
1155
1156
1157 ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
1158 if (ret < 0) {
1159 return ret;
1160 }
1161
1162 cluster_offset = be64_to_cpu(l2_slice[l2_index]);
1163
1164
1165 if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL
1166 && (cluster_offset & QCOW_OFLAG_COPIED))
1167 {
1168
1169 bool offset_matches =
1170 (cluster_offset & L2E_OFFSET_MASK) == *host_offset;
1171
1172 if (offset_into_cluster(s, cluster_offset & L2E_OFFSET_MASK)) {
1173 qcow2_signal_corruption(bs, true, -1, -1, "Data cluster offset "
1174 "%#llx unaligned (guest offset: %#" PRIx64
1175 ")", cluster_offset & L2E_OFFSET_MASK,
1176 guest_offset);
1177 ret = -EIO;
1178 goto out;
1179 }
1180
1181 if (*host_offset != 0 && !offset_matches) {
1182 *bytes = 0;
1183 ret = 0;
1184 goto out;
1185 }
1186
1187
1188 keep_clusters =
1189 count_contiguous_clusters(nb_clusters, s->cluster_size,
1190 &l2_slice[l2_index],
1191 QCOW_OFLAG_COPIED | QCOW_OFLAG_ZERO);
1192 assert(keep_clusters <= nb_clusters);
1193
1194 *bytes = MIN(*bytes,
1195 keep_clusters * s->cluster_size
1196 - offset_into_cluster(s, guest_offset));
1197
1198 ret = 1;
1199 } else {
1200 ret = 0;
1201 }
1202
1203
1204out:
1205 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1206
1207
1208
1209 if (ret > 0) {
1210 *host_offset = (cluster_offset & L2E_OFFSET_MASK)
1211 + offset_into_cluster(s, guest_offset);
1212 }
1213
1214 return ret;
1215}
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
1237 uint64_t *host_offset, uint64_t *nb_clusters)
1238{
1239 BDRVQcow2State *s = bs->opaque;
1240
1241 trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
1242 *host_offset, *nb_clusters);
1243
1244
1245 trace_qcow2_cluster_alloc_phys(qemu_coroutine_self());
1246 if (*host_offset == 0) {
1247 int64_t cluster_offset =
1248 qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size);
1249 if (cluster_offset < 0) {
1250 return cluster_offset;
1251 }
1252 *host_offset = cluster_offset;
1253 return 0;
1254 } else {
1255 int64_t ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
1256 if (ret < 0) {
1257 return ret;
1258 }
1259 *nb_clusters = ret;
1260 return 0;
1261 }
1262}
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
1285 uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
1286{
1287 BDRVQcow2State *s = bs->opaque;
1288 int l2_index;
1289 uint64_t *l2_slice;
1290 uint64_t entry;
1291 uint64_t nb_clusters;
1292 int ret;
1293 bool keep_old_clusters = false;
1294
1295 uint64_t alloc_cluster_offset = 0;
1296
1297 trace_qcow2_handle_alloc(qemu_coroutine_self(), guest_offset, *host_offset,
1298 *bytes);
1299 assert(*bytes > 0);
1300
1301
1302
1303
1304
1305 nb_clusters =
1306 size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
1307
1308 l2_index = offset_to_l2_slice_index(s, guest_offset);
1309 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1310 assert(nb_clusters <= INT_MAX);
1311
1312
1313 ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
1314 if (ret < 0) {
1315 return ret;
1316 }
1317
1318 entry = be64_to_cpu(l2_slice[l2_index]);
1319
1320
1321 if (entry & QCOW_OFLAG_COMPRESSED) {
1322 nb_clusters = 1;
1323 } else {
1324 nb_clusters = count_cow_clusters(s, nb_clusters, l2_slice, l2_index);
1325 }
1326
1327
1328
1329
1330 assert(nb_clusters > 0);
1331
1332 if (qcow2_get_cluster_type(entry) == QCOW2_CLUSTER_ZERO_ALLOC &&
1333 (entry & QCOW_OFLAG_COPIED) &&
1334 (!*host_offset ||
1335 start_of_cluster(s, *host_offset) == (entry & L2E_OFFSET_MASK)))
1336 {
1337 int preallocated_nb_clusters;
1338
1339 if (offset_into_cluster(s, entry & L2E_OFFSET_MASK)) {
1340 qcow2_signal_corruption(bs, true, -1, -1, "Preallocated zero "
1341 "cluster offset %#llx unaligned (guest "
1342 "offset: %#" PRIx64 ")",
1343 entry & L2E_OFFSET_MASK, guest_offset);
1344 ret = -EIO;
1345 goto fail;
1346 }
1347
1348
1349
1350
1351 preallocated_nb_clusters =
1352 count_contiguous_clusters(nb_clusters, s->cluster_size,
1353 &l2_slice[l2_index], QCOW_OFLAG_COPIED);
1354 assert(preallocated_nb_clusters > 0);
1355
1356 nb_clusters = preallocated_nb_clusters;
1357 alloc_cluster_offset = entry & L2E_OFFSET_MASK;
1358
1359
1360
1361 keep_old_clusters = true;
1362 }
1363
1364 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1365
1366 if (!alloc_cluster_offset) {
1367
1368 alloc_cluster_offset = start_of_cluster(s, *host_offset);
1369 ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset,
1370 &nb_clusters);
1371 if (ret < 0) {
1372 goto fail;
1373 }
1374
1375
1376 if (nb_clusters == 0) {
1377 *bytes = 0;
1378 return 0;
1379 }
1380
1381
1382
1383
1384
1385 if (!alloc_cluster_offset) {
1386 ret = qcow2_pre_write_overlap_check(bs, 0, alloc_cluster_offset,
1387 nb_clusters * s->cluster_size);
1388 assert(ret < 0);
1389 goto fail;
1390 }
1391 }
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407 uint64_t requested_bytes = *bytes + offset_into_cluster(s, guest_offset);
1408 int avail_bytes = MIN(INT_MAX, nb_clusters << s->cluster_bits);
1409 int nb_bytes = MIN(requested_bytes, avail_bytes);
1410 QCowL2Meta *old_m = *m;
1411
1412 *m = g_malloc0(sizeof(**m));
1413
1414 **m = (QCowL2Meta) {
1415 .next = old_m,
1416
1417 .alloc_offset = alloc_cluster_offset,
1418 .offset = start_of_cluster(s, guest_offset),
1419 .nb_clusters = nb_clusters,
1420
1421 .keep_old_clusters = keep_old_clusters,
1422
1423 .cow_start = {
1424 .offset = 0,
1425 .nb_bytes = offset_into_cluster(s, guest_offset),
1426 },
1427 .cow_end = {
1428 .offset = nb_bytes,
1429 .nb_bytes = avail_bytes - nb_bytes,
1430 },
1431 };
1432 qemu_co_queue_init(&(*m)->dependent_requests);
1433 QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
1434
1435 *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset);
1436 *bytes = MIN(*bytes, nb_bytes - offset_into_cluster(s, guest_offset));
1437 assert(*bytes != 0);
1438
1439 return 1;
1440
1441fail:
1442 if (*m && (*m)->nb_clusters > 0) {
1443 QLIST_REMOVE(*m, next_in_flight);
1444 }
1445 return ret;
1446}
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
1468 unsigned int *bytes, uint64_t *host_offset,
1469 QCowL2Meta **m)
1470{
1471 BDRVQcow2State *s = bs->opaque;
1472 uint64_t start, remaining;
1473 uint64_t cluster_offset;
1474 uint64_t cur_bytes;
1475 int ret;
1476
1477 trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *bytes);
1478
1479again:
1480 start = offset;
1481 remaining = *bytes;
1482 cluster_offset = 0;
1483 *host_offset = 0;
1484 cur_bytes = 0;
1485 *m = NULL;
1486
1487 while (true) {
1488
1489 if (!*host_offset) {
1490 *host_offset = start_of_cluster(s, cluster_offset);
1491 }
1492
1493 assert(remaining >= cur_bytes);
1494
1495 start += cur_bytes;
1496 remaining -= cur_bytes;
1497 cluster_offset += cur_bytes;
1498
1499 if (remaining == 0) {
1500 break;
1501 }
1502
1503 cur_bytes = remaining;
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523 ret = handle_dependencies(bs, start, &cur_bytes, m);
1524 if (ret == -EAGAIN) {
1525
1526
1527
1528 assert(*m == NULL);
1529 goto again;
1530 } else if (ret < 0) {
1531 return ret;
1532 } else if (cur_bytes == 0) {
1533 break;
1534 } else {
1535
1536
1537
1538 }
1539
1540
1541
1542
1543 ret = handle_copied(bs, start, &cluster_offset, &cur_bytes, m);
1544 if (ret < 0) {
1545 return ret;
1546 } else if (ret) {
1547 continue;
1548 } else if (cur_bytes == 0) {
1549 break;
1550 }
1551
1552
1553
1554
1555
1556 ret = handle_alloc(bs, start, &cluster_offset, &cur_bytes, m);
1557 if (ret < 0) {
1558 return ret;
1559 } else if (ret) {
1560 continue;
1561 } else {
1562 assert(cur_bytes == 0);
1563 break;
1564 }
1565 }
1566
1567 *bytes -= remaining;
1568 assert(*bytes > 0);
1569 assert(*host_offset != 0);
1570
1571 return 0;
1572}
1573
1574static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
1575 const uint8_t *buf, int buf_size)
1576{
1577 z_stream strm1, *strm = &strm1;
1578 int ret, out_len;
1579
1580 memset(strm, 0, sizeof(*strm));
1581
1582 strm->next_in = (uint8_t *)buf;
1583 strm->avail_in = buf_size;
1584 strm->next_out = out_buf;
1585 strm->avail_out = out_buf_size;
1586
1587 ret = inflateInit2(strm, -12);
1588 if (ret != Z_OK)
1589 return -1;
1590 ret = inflate(strm, Z_FINISH);
1591 out_len = strm->next_out - out_buf;
1592 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
1593 out_len != out_buf_size) {
1594 inflateEnd(strm);
1595 return -1;
1596 }
1597 inflateEnd(strm);
1598 return 0;
1599}
1600
1601int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
1602{
1603 BDRVQcow2State *s = bs->opaque;
1604 int ret, csize, nb_csectors, sector_offset;
1605 uint64_t coffset;
1606
1607 coffset = cluster_offset & s->cluster_offset_mask;
1608 if (s->cluster_cache_offset != coffset) {
1609 nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
1610 sector_offset = coffset & 511;
1611 csize = nb_csectors * 512 - sector_offset;
1612
1613
1614
1615
1616
1617 if (!s->cluster_data) {
1618
1619 s->cluster_data = qemu_try_blockalign(bs->file->bs,
1620 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size + 512);
1621 if (!s->cluster_data) {
1622 return -ENOMEM;
1623 }
1624 }
1625 if (!s->cluster_cache) {
1626 s->cluster_cache = g_malloc(s->cluster_size);
1627 }
1628
1629 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
1630 ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data,
1631 nb_csectors);
1632 if (ret < 0) {
1633 return ret;
1634 }
1635 if (decompress_buffer(s->cluster_cache, s->cluster_size,
1636 s->cluster_data + sector_offset, csize) < 0) {
1637 return -EIO;
1638 }
1639 s->cluster_cache_offset = coffset;
1640 }
1641 return 0;
1642}
1643
1644
1645
1646
1647
1648
1649static int discard_in_l2_slice(BlockDriverState *bs, uint64_t offset,
1650 uint64_t nb_clusters,
1651 enum qcow2_discard_type type, bool full_discard)
1652{
1653 BDRVQcow2State *s = bs->opaque;
1654 uint64_t *l2_slice;
1655 int l2_index;
1656 int ret;
1657 int i;
1658
1659 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
1660 if (ret < 0) {
1661 return ret;
1662 }
1663
1664
1665 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1666 assert(nb_clusters <= INT_MAX);
1667
1668 for (i = 0; i < nb_clusters; i++) {
1669 uint64_t old_l2_entry;
1670
1671 old_l2_entry = be64_to_cpu(l2_slice[l2_index + i]);
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686 switch (qcow2_get_cluster_type(old_l2_entry)) {
1687 case QCOW2_CLUSTER_UNALLOCATED:
1688 if (full_discard || !bs->backing) {
1689 continue;
1690 }
1691 break;
1692
1693 case QCOW2_CLUSTER_ZERO_PLAIN:
1694 if (!full_discard) {
1695 continue;
1696 }
1697 break;
1698
1699 case QCOW2_CLUSTER_ZERO_ALLOC:
1700 case QCOW2_CLUSTER_NORMAL:
1701 case QCOW2_CLUSTER_COMPRESSED:
1702 break;
1703
1704 default:
1705 abort();
1706 }
1707
1708
1709 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
1710 if (!full_discard && s->qcow_version >= 3) {
1711 l2_slice[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
1712 } else {
1713 l2_slice[l2_index + i] = cpu_to_be64(0);
1714 }
1715
1716
1717 qcow2_free_any_clusters(bs, old_l2_entry, 1, type);
1718 }
1719
1720 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1721
1722 return nb_clusters;
1723}
1724
1725int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
1726 uint64_t bytes, enum qcow2_discard_type type,
1727 bool full_discard)
1728{
1729 BDRVQcow2State *s = bs->opaque;
1730 uint64_t end_offset = offset + bytes;
1731 uint64_t nb_clusters;
1732 int64_t cleared;
1733 int ret;
1734
1735
1736 assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
1737 assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) ||
1738 end_offset == bs->total_sectors << BDRV_SECTOR_BITS);
1739
1740 nb_clusters = size_to_clusters(s, bytes);
1741
1742 s->cache_discards = true;
1743
1744
1745 while (nb_clusters > 0) {
1746 cleared = discard_in_l2_slice(bs, offset, nb_clusters, type,
1747 full_discard);
1748 if (cleared < 0) {
1749 ret = cleared;
1750 goto fail;
1751 }
1752
1753 nb_clusters -= cleared;
1754 offset += (cleared * s->cluster_size);
1755 }
1756
1757 ret = 0;
1758fail:
1759 s->cache_discards = false;
1760 qcow2_process_discards(bs, ret);
1761
1762 return ret;
1763}
1764
1765
1766
1767
1768
1769
1770static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset,
1771 uint64_t nb_clusters, int flags)
1772{
1773 BDRVQcow2State *s = bs->opaque;
1774 uint64_t *l2_slice;
1775 int l2_index;
1776 int ret;
1777 int i;
1778 bool unmap = !!(flags & BDRV_REQ_MAY_UNMAP);
1779
1780 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
1781 if (ret < 0) {
1782 return ret;
1783 }
1784
1785
1786 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1787 assert(nb_clusters <= INT_MAX);
1788
1789 for (i = 0; i < nb_clusters; i++) {
1790 uint64_t old_offset;
1791 QCow2ClusterType cluster_type;
1792
1793 old_offset = be64_to_cpu(l2_slice[l2_index + i]);
1794
1795
1796
1797
1798
1799 cluster_type = qcow2_get_cluster_type(old_offset);
1800 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN ||
1801 (cluster_type == QCOW2_CLUSTER_ZERO_ALLOC && !unmap)) {
1802 continue;
1803 }
1804
1805 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
1806 if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) {
1807 l2_slice[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
1808 qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST);
1809 } else {
1810 l2_slice[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO);
1811 }
1812 }
1813
1814 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1815
1816 return nb_clusters;
1817}
1818
1819int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
1820 uint64_t bytes, int flags)
1821{
1822 BDRVQcow2State *s = bs->opaque;
1823 uint64_t end_offset = offset + bytes;
1824 uint64_t nb_clusters;
1825 int64_t cleared;
1826 int ret;
1827
1828
1829 assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
1830 assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) ||
1831 end_offset == bs->total_sectors << BDRV_SECTOR_BITS);
1832
1833
1834 if (s->qcow_version < 3) {
1835 return -ENOTSUP;
1836 }
1837
1838
1839 nb_clusters = size_to_clusters(s, bytes);
1840
1841 s->cache_discards = true;
1842
1843 while (nb_clusters > 0) {
1844 cleared = zero_in_l2_slice(bs, offset, nb_clusters, flags);
1845 if (cleared < 0) {
1846 ret = cleared;
1847 goto fail;
1848 }
1849
1850 nb_clusters -= cleared;
1851 offset += (cleared * s->cluster_size);
1852 }
1853
1854 ret = 0;
1855fail:
1856 s->cache_discards = false;
1857 qcow2_process_discards(bs, ret);
1858
1859 return ret;
1860}
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
1871 int l1_size, int64_t *visited_l1_entries,
1872 int64_t l1_entries,
1873 BlockDriverAmendStatusCB *status_cb,
1874 void *cb_opaque)
1875{
1876 BDRVQcow2State *s = bs->opaque;
1877 bool is_active_l1 = (l1_table == s->l1_table);
1878 uint64_t *l2_slice = NULL;
1879 unsigned slice, slice_size2, n_slices;
1880 int ret;
1881 int i, j;
1882
1883 slice_size2 = s->l2_slice_size * sizeof(uint64_t);
1884 n_slices = s->cluster_size / slice_size2;
1885
1886 if (!is_active_l1) {
1887
1888
1889 l2_slice = qemu_try_blockalign(bs->file->bs, slice_size2);
1890 if (l2_slice == NULL) {
1891 return -ENOMEM;
1892 }
1893 }
1894
1895 for (i = 0; i < l1_size; i++) {
1896 uint64_t l2_offset = l1_table[i] & L1E_OFFSET_MASK;
1897 uint64_t l2_refcount;
1898
1899 if (!l2_offset) {
1900
1901 (*visited_l1_entries)++;
1902 if (status_cb) {
1903 status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque);
1904 }
1905 continue;
1906 }
1907
1908 if (offset_into_cluster(s, l2_offset)) {
1909 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#"
1910 PRIx64 " unaligned (L1 index: %#x)",
1911 l2_offset, i);
1912 ret = -EIO;
1913 goto fail;
1914 }
1915
1916 ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits,
1917 &l2_refcount);
1918 if (ret < 0) {
1919 goto fail;
1920 }
1921
1922 for (slice = 0; slice < n_slices; slice++) {
1923 uint64_t slice_offset = l2_offset + slice * slice_size2;
1924 bool l2_dirty = false;
1925 if (is_active_l1) {
1926
1927 ret = qcow2_cache_get(bs, s->l2_table_cache, slice_offset,
1928 (void **)&l2_slice);
1929 } else {
1930
1931 ret = bdrv_pread(bs->file, slice_offset, l2_slice, slice_size2);
1932 }
1933 if (ret < 0) {
1934 goto fail;
1935 }
1936
1937 for (j = 0; j < s->l2_slice_size; j++) {
1938 uint64_t l2_entry = be64_to_cpu(l2_slice[j]);
1939 int64_t offset = l2_entry & L2E_OFFSET_MASK;
1940 QCow2ClusterType cluster_type =
1941 qcow2_get_cluster_type(l2_entry);
1942
1943 if (cluster_type != QCOW2_CLUSTER_ZERO_PLAIN &&
1944 cluster_type != QCOW2_CLUSTER_ZERO_ALLOC) {
1945 continue;
1946 }
1947
1948 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1949 if (!bs->backing) {
1950
1951
1952 l2_slice[j] = 0;
1953 l2_dirty = true;
1954 continue;
1955 }
1956
1957 offset = qcow2_alloc_clusters(bs, s->cluster_size);
1958 if (offset < 0) {
1959 ret = offset;
1960 goto fail;
1961 }
1962
1963 if (l2_refcount > 1) {
1964
1965
1966 ret = qcow2_update_cluster_refcount(
1967 bs, offset >> s->cluster_bits,
1968 refcount_diff(1, l2_refcount), false,
1969 QCOW2_DISCARD_OTHER);
1970 if (ret < 0) {
1971 qcow2_free_clusters(bs, offset, s->cluster_size,
1972 QCOW2_DISCARD_OTHER);
1973 goto fail;
1974 }
1975 }
1976 }
1977
1978 if (offset_into_cluster(s, offset)) {
1979 int l2_index = slice * s->l2_slice_size + j;
1980 qcow2_signal_corruption(
1981 bs, true, -1, -1,
1982 "Cluster allocation offset "
1983 "%#" PRIx64 " unaligned (L2 offset: %#"
1984 PRIx64 ", L2 index: %#x)", offset,
1985 l2_offset, l2_index);
1986 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1987 qcow2_free_clusters(bs, offset, s->cluster_size,
1988 QCOW2_DISCARD_ALWAYS);
1989 }
1990 ret = -EIO;
1991 goto fail;
1992 }
1993
1994 ret = qcow2_pre_write_overlap_check(bs, 0, offset,
1995 s->cluster_size);
1996 if (ret < 0) {
1997 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1998 qcow2_free_clusters(bs, offset, s->cluster_size,
1999 QCOW2_DISCARD_ALWAYS);
2000 }
2001 goto fail;
2002 }
2003
2004 ret = bdrv_pwrite_zeroes(bs->file, offset, s->cluster_size, 0);
2005 if (ret < 0) {
2006 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
2007 qcow2_free_clusters(bs, offset, s->cluster_size,
2008 QCOW2_DISCARD_ALWAYS);
2009 }
2010 goto fail;
2011 }
2012
2013 if (l2_refcount == 1) {
2014 l2_slice[j] = cpu_to_be64(offset | QCOW_OFLAG_COPIED);
2015 } else {
2016 l2_slice[j] = cpu_to_be64(offset);
2017 }
2018 l2_dirty = true;
2019 }
2020
2021 if (is_active_l1) {
2022 if (l2_dirty) {
2023 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
2024 qcow2_cache_depends_on_flush(s->l2_table_cache);
2025 }
2026 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2027 } else {
2028 if (l2_dirty) {
2029 ret = qcow2_pre_write_overlap_check(
2030 bs, QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2,
2031 slice_offset, slice_size2);
2032 if (ret < 0) {
2033 goto fail;
2034 }
2035
2036 ret = bdrv_pwrite(bs->file, slice_offset,
2037 l2_slice, slice_size2);
2038 if (ret < 0) {
2039 goto fail;
2040 }
2041 }
2042 }
2043 }
2044
2045 (*visited_l1_entries)++;
2046 if (status_cb) {
2047 status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque);
2048 }
2049 }
2050
2051 ret = 0;
2052
2053fail:
2054 if (l2_slice) {
2055 if (!is_active_l1) {
2056 qemu_vfree(l2_slice);
2057 } else {
2058 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2059 }
2060 }
2061 return ret;
2062}
2063
2064
2065
2066
2067
2068
2069
2070int qcow2_expand_zero_clusters(BlockDriverState *bs,
2071 BlockDriverAmendStatusCB *status_cb,
2072 void *cb_opaque)
2073{
2074 BDRVQcow2State *s = bs->opaque;
2075 uint64_t *l1_table = NULL;
2076 int64_t l1_entries = 0, visited_l1_entries = 0;
2077 int ret;
2078 int i, j;
2079
2080 if (status_cb) {
2081 l1_entries = s->l1_size;
2082 for (i = 0; i < s->nb_snapshots; i++) {
2083 l1_entries += s->snapshots[i].l1_size;
2084 }
2085 }
2086
2087 ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size,
2088 &visited_l1_entries, l1_entries,
2089 status_cb, cb_opaque);
2090 if (ret < 0) {
2091 goto fail;
2092 }
2093
2094
2095
2096
2097
2098
2099
2100
2101 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2102 if (ret < 0) {
2103 goto fail;
2104 }
2105
2106 for (i = 0; i < s->nb_snapshots; i++) {
2107 int l1_size2;
2108 uint64_t *new_l1_table;
2109 Error *local_err = NULL;
2110
2111 ret = qcow2_validate_table(bs, s->snapshots[i].l1_table_offset,
2112 s->snapshots[i].l1_size, sizeof(uint64_t),
2113 QCOW_MAX_L1_SIZE, "Snapshot L1 table",
2114 &local_err);
2115 if (ret < 0) {
2116 error_report_err(local_err);
2117 goto fail;
2118 }
2119
2120 l1_size2 = s->snapshots[i].l1_size * sizeof(uint64_t);
2121 new_l1_table = g_try_realloc(l1_table, l1_size2);
2122
2123 if (!new_l1_table) {
2124 ret = -ENOMEM;
2125 goto fail;
2126 }
2127
2128 l1_table = new_l1_table;
2129
2130 ret = bdrv_pread(bs->file, s->snapshots[i].l1_table_offset,
2131 l1_table, l1_size2);
2132 if (ret < 0) {
2133 goto fail;
2134 }
2135
2136 for (j = 0; j < s->snapshots[i].l1_size; j++) {
2137 be64_to_cpus(&l1_table[j]);
2138 }
2139
2140 ret = expand_zero_clusters_in_l1(bs, l1_table, s->snapshots[i].l1_size,
2141 &visited_l1_entries, l1_entries,
2142 status_cb, cb_opaque);
2143 if (ret < 0) {
2144 goto fail;
2145 }
2146 }
2147
2148 ret = 0;
2149
2150fail:
2151 g_free(l1_table);
2152 return ret;
2153}
2154