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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 "block/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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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
1001
1002static int count_cow_clusters(BDRVQcow2State *s, int nb_clusters,
1003 uint64_t *l2_slice, int l2_index)
1004{
1005 int i;
1006
1007 for (i = 0; i < nb_clusters; i++) {
1008 uint64_t l2_entry = be64_to_cpu(l2_slice[l2_index + i]);
1009 QCow2ClusterType cluster_type = qcow2_get_cluster_type(l2_entry);
1010
1011 switch(cluster_type) {
1012 case QCOW2_CLUSTER_NORMAL:
1013 if (l2_entry & QCOW_OFLAG_COPIED) {
1014 goto out;
1015 }
1016 break;
1017 case QCOW2_CLUSTER_UNALLOCATED:
1018 case QCOW2_CLUSTER_COMPRESSED:
1019 case QCOW2_CLUSTER_ZERO_PLAIN:
1020 case QCOW2_CLUSTER_ZERO_ALLOC:
1021 break;
1022 default:
1023 abort();
1024 }
1025 }
1026
1027out:
1028 assert(i <= nb_clusters);
1029 return i;
1030}
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
1047 uint64_t *cur_bytes, QCowL2Meta **m)
1048{
1049 BDRVQcow2State *s = bs->opaque;
1050 QCowL2Meta *old_alloc;
1051 uint64_t bytes = *cur_bytes;
1052
1053 QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
1054
1055 uint64_t start = guest_offset;
1056 uint64_t end = start + bytes;
1057 uint64_t old_start = l2meta_cow_start(old_alloc);
1058 uint64_t old_end = l2meta_cow_end(old_alloc);
1059
1060 if (end <= old_start || start >= old_end) {
1061
1062 } else {
1063 if (start < old_start) {
1064
1065 bytes = old_start - start;
1066 } else {
1067 bytes = 0;
1068 }
1069
1070
1071
1072
1073
1074 if (bytes == 0 && *m) {
1075 *cur_bytes = 0;
1076 return 0;
1077 }
1078
1079 if (bytes == 0) {
1080
1081
1082 qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock);
1083 return -EAGAIN;
1084 }
1085 }
1086 }
1087
1088
1089
1090 *cur_bytes = bytes;
1091
1092 return 0;
1093}
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
1118 uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
1119{
1120 BDRVQcow2State *s = bs->opaque;
1121 int l2_index;
1122 uint64_t cluster_offset;
1123 uint64_t *l2_slice;
1124 uint64_t nb_clusters;
1125 unsigned int keep_clusters;
1126 int ret;
1127
1128 trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset,
1129 *bytes);
1130
1131 assert(*host_offset == 0 || offset_into_cluster(s, guest_offset)
1132 == offset_into_cluster(s, *host_offset));
1133
1134
1135
1136
1137
1138 nb_clusters =
1139 size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
1140
1141 l2_index = offset_to_l2_slice_index(s, guest_offset);
1142 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1143 assert(nb_clusters <= INT_MAX);
1144
1145
1146 ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
1147 if (ret < 0) {
1148 return ret;
1149 }
1150
1151 cluster_offset = be64_to_cpu(l2_slice[l2_index]);
1152
1153
1154 if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL
1155 && (cluster_offset & QCOW_OFLAG_COPIED))
1156 {
1157
1158 bool offset_matches =
1159 (cluster_offset & L2E_OFFSET_MASK) == *host_offset;
1160
1161 if (offset_into_cluster(s, cluster_offset & L2E_OFFSET_MASK)) {
1162 qcow2_signal_corruption(bs, true, -1, -1, "Data cluster offset "
1163 "%#llx unaligned (guest offset: %#" PRIx64
1164 ")", cluster_offset & L2E_OFFSET_MASK,
1165 guest_offset);
1166 ret = -EIO;
1167 goto out;
1168 }
1169
1170 if (*host_offset != 0 && !offset_matches) {
1171 *bytes = 0;
1172 ret = 0;
1173 goto out;
1174 }
1175
1176
1177 keep_clusters =
1178 count_contiguous_clusters(nb_clusters, s->cluster_size,
1179 &l2_slice[l2_index],
1180 QCOW_OFLAG_COPIED | QCOW_OFLAG_ZERO);
1181 assert(keep_clusters <= nb_clusters);
1182
1183 *bytes = MIN(*bytes,
1184 keep_clusters * s->cluster_size
1185 - offset_into_cluster(s, guest_offset));
1186
1187 ret = 1;
1188 } else {
1189 ret = 0;
1190 }
1191
1192
1193out:
1194 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1195
1196
1197
1198 if (ret > 0) {
1199 *host_offset = (cluster_offset & L2E_OFFSET_MASK)
1200 + offset_into_cluster(s, guest_offset);
1201 }
1202
1203 return ret;
1204}
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
1226 uint64_t *host_offset, uint64_t *nb_clusters)
1227{
1228 BDRVQcow2State *s = bs->opaque;
1229
1230 trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
1231 *host_offset, *nb_clusters);
1232
1233
1234 trace_qcow2_cluster_alloc_phys(qemu_coroutine_self());
1235 if (*host_offset == 0) {
1236 int64_t cluster_offset =
1237 qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size);
1238 if (cluster_offset < 0) {
1239 return cluster_offset;
1240 }
1241 *host_offset = cluster_offset;
1242 return 0;
1243 } else {
1244 int64_t ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
1245 if (ret < 0) {
1246 return ret;
1247 }
1248 *nb_clusters = ret;
1249 return 0;
1250 }
1251}
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
1274 uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
1275{
1276 BDRVQcow2State *s = bs->opaque;
1277 int l2_index;
1278 uint64_t *l2_slice;
1279 uint64_t entry;
1280 uint64_t nb_clusters;
1281 int ret;
1282 bool keep_old_clusters = false;
1283
1284 uint64_t alloc_cluster_offset = 0;
1285
1286 trace_qcow2_handle_alloc(qemu_coroutine_self(), guest_offset, *host_offset,
1287 *bytes);
1288 assert(*bytes > 0);
1289
1290
1291
1292
1293
1294 nb_clusters =
1295 size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
1296
1297 l2_index = offset_to_l2_slice_index(s, guest_offset);
1298 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1299 assert(nb_clusters <= INT_MAX);
1300
1301
1302 ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
1303 if (ret < 0) {
1304 return ret;
1305 }
1306
1307 entry = be64_to_cpu(l2_slice[l2_index]);
1308
1309
1310 if (entry & QCOW_OFLAG_COMPRESSED) {
1311 nb_clusters = 1;
1312 } else {
1313 nb_clusters = count_cow_clusters(s, nb_clusters, l2_slice, l2_index);
1314 }
1315
1316
1317
1318
1319 assert(nb_clusters > 0);
1320
1321 if (qcow2_get_cluster_type(entry) == QCOW2_CLUSTER_ZERO_ALLOC &&
1322 (entry & QCOW_OFLAG_COPIED) &&
1323 (!*host_offset ||
1324 start_of_cluster(s, *host_offset) == (entry & L2E_OFFSET_MASK)))
1325 {
1326 int preallocated_nb_clusters;
1327
1328 if (offset_into_cluster(s, entry & L2E_OFFSET_MASK)) {
1329 qcow2_signal_corruption(bs, true, -1, -1, "Preallocated zero "
1330 "cluster offset %#llx unaligned (guest "
1331 "offset: %#" PRIx64 ")",
1332 entry & L2E_OFFSET_MASK, guest_offset);
1333 ret = -EIO;
1334 goto fail;
1335 }
1336
1337
1338
1339
1340 preallocated_nb_clusters =
1341 count_contiguous_clusters(nb_clusters, s->cluster_size,
1342 &l2_slice[l2_index], QCOW_OFLAG_COPIED);
1343 assert(preallocated_nb_clusters > 0);
1344
1345 nb_clusters = preallocated_nb_clusters;
1346 alloc_cluster_offset = entry & L2E_OFFSET_MASK;
1347
1348
1349
1350 keep_old_clusters = true;
1351 }
1352
1353 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1354
1355 if (!alloc_cluster_offset) {
1356
1357 alloc_cluster_offset = start_of_cluster(s, *host_offset);
1358 ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset,
1359 &nb_clusters);
1360 if (ret < 0) {
1361 goto fail;
1362 }
1363
1364
1365 if (nb_clusters == 0) {
1366 *bytes = 0;
1367 return 0;
1368 }
1369
1370
1371
1372
1373
1374 if (!alloc_cluster_offset) {
1375 ret = qcow2_pre_write_overlap_check(bs, 0, alloc_cluster_offset,
1376 nb_clusters * s->cluster_size);
1377 assert(ret < 0);
1378 goto fail;
1379 }
1380 }
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396 uint64_t requested_bytes = *bytes + offset_into_cluster(s, guest_offset);
1397 int avail_bytes = MIN(INT_MAX, nb_clusters << s->cluster_bits);
1398 int nb_bytes = MIN(requested_bytes, avail_bytes);
1399 QCowL2Meta *old_m = *m;
1400
1401 *m = g_malloc0(sizeof(**m));
1402
1403 **m = (QCowL2Meta) {
1404 .next = old_m,
1405
1406 .alloc_offset = alloc_cluster_offset,
1407 .offset = start_of_cluster(s, guest_offset),
1408 .nb_clusters = nb_clusters,
1409
1410 .keep_old_clusters = keep_old_clusters,
1411
1412 .cow_start = {
1413 .offset = 0,
1414 .nb_bytes = offset_into_cluster(s, guest_offset),
1415 },
1416 .cow_end = {
1417 .offset = nb_bytes,
1418 .nb_bytes = avail_bytes - nb_bytes,
1419 },
1420 };
1421 qemu_co_queue_init(&(*m)->dependent_requests);
1422 QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
1423
1424 *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset);
1425 *bytes = MIN(*bytes, nb_bytes - offset_into_cluster(s, guest_offset));
1426 assert(*bytes != 0);
1427
1428 return 1;
1429
1430fail:
1431 if (*m && (*m)->nb_clusters > 0) {
1432 QLIST_REMOVE(*m, next_in_flight);
1433 }
1434 return ret;
1435}
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
1457 unsigned int *bytes, uint64_t *host_offset,
1458 QCowL2Meta **m)
1459{
1460 BDRVQcow2State *s = bs->opaque;
1461 uint64_t start, remaining;
1462 uint64_t cluster_offset;
1463 uint64_t cur_bytes;
1464 int ret;
1465
1466 trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *bytes);
1467
1468again:
1469 start = offset;
1470 remaining = *bytes;
1471 cluster_offset = 0;
1472 *host_offset = 0;
1473 cur_bytes = 0;
1474 *m = NULL;
1475
1476 while (true) {
1477
1478 if (!*host_offset) {
1479 *host_offset = start_of_cluster(s, cluster_offset);
1480 }
1481
1482 assert(remaining >= cur_bytes);
1483
1484 start += cur_bytes;
1485 remaining -= cur_bytes;
1486 cluster_offset += cur_bytes;
1487
1488 if (remaining == 0) {
1489 break;
1490 }
1491
1492 cur_bytes = remaining;
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512 ret = handle_dependencies(bs, start, &cur_bytes, m);
1513 if (ret == -EAGAIN) {
1514
1515
1516
1517 assert(*m == NULL);
1518 goto again;
1519 } else if (ret < 0) {
1520 return ret;
1521 } else if (cur_bytes == 0) {
1522 break;
1523 } else {
1524
1525
1526
1527 }
1528
1529
1530
1531
1532 ret = handle_copied(bs, start, &cluster_offset, &cur_bytes, m);
1533 if (ret < 0) {
1534 return ret;
1535 } else if (ret) {
1536 continue;
1537 } else if (cur_bytes == 0) {
1538 break;
1539 }
1540
1541
1542
1543
1544
1545 ret = handle_alloc(bs, start, &cluster_offset, &cur_bytes, m);
1546 if (ret < 0) {
1547 return ret;
1548 } else if (ret) {
1549 continue;
1550 } else {
1551 assert(cur_bytes == 0);
1552 break;
1553 }
1554 }
1555
1556 *bytes -= remaining;
1557 assert(*bytes > 0);
1558 assert(*host_offset != 0);
1559
1560 return 0;
1561}
1562
1563static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
1564 const uint8_t *buf, int buf_size)
1565{
1566 z_stream strm1, *strm = &strm1;
1567 int ret, out_len;
1568
1569 memset(strm, 0, sizeof(*strm));
1570
1571 strm->next_in = (uint8_t *)buf;
1572 strm->avail_in = buf_size;
1573 strm->next_out = out_buf;
1574 strm->avail_out = out_buf_size;
1575
1576 ret = inflateInit2(strm, -12);
1577 if (ret != Z_OK)
1578 return -1;
1579 ret = inflate(strm, Z_FINISH);
1580 out_len = strm->next_out - out_buf;
1581 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
1582 out_len != out_buf_size) {
1583 inflateEnd(strm);
1584 return -1;
1585 }
1586 inflateEnd(strm);
1587 return 0;
1588}
1589
1590int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
1591{
1592 BDRVQcow2State *s = bs->opaque;
1593 int ret, csize, nb_csectors, sector_offset;
1594 uint64_t coffset;
1595
1596 coffset = cluster_offset & s->cluster_offset_mask;
1597 if (s->cluster_cache_offset != coffset) {
1598 nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
1599 sector_offset = coffset & 511;
1600 csize = nb_csectors * 512 - sector_offset;
1601
1602
1603
1604
1605
1606 if (!s->cluster_data) {
1607
1608 s->cluster_data = qemu_try_blockalign(bs->file->bs,
1609 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size + 512);
1610 if (!s->cluster_data) {
1611 return -ENOMEM;
1612 }
1613 }
1614 if (!s->cluster_cache) {
1615 s->cluster_cache = g_malloc(s->cluster_size);
1616 }
1617
1618 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
1619 ret = bdrv_read(bs->file, coffset >> 9, s->cluster_data,
1620 nb_csectors);
1621 if (ret < 0) {
1622 return ret;
1623 }
1624 if (decompress_buffer(s->cluster_cache, s->cluster_size,
1625 s->cluster_data + sector_offset, csize) < 0) {
1626 return -EIO;
1627 }
1628 s->cluster_cache_offset = coffset;
1629 }
1630 return 0;
1631}
1632
1633
1634
1635
1636
1637
1638static int discard_in_l2_slice(BlockDriverState *bs, uint64_t offset,
1639 uint64_t nb_clusters,
1640 enum qcow2_discard_type type, bool full_discard)
1641{
1642 BDRVQcow2State *s = bs->opaque;
1643 uint64_t *l2_slice;
1644 int l2_index;
1645 int ret;
1646 int i;
1647
1648 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
1649 if (ret < 0) {
1650 return ret;
1651 }
1652
1653
1654 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1655 assert(nb_clusters <= INT_MAX);
1656
1657 for (i = 0; i < nb_clusters; i++) {
1658 uint64_t old_l2_entry;
1659
1660 old_l2_entry = be64_to_cpu(l2_slice[l2_index + i]);
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675 switch (qcow2_get_cluster_type(old_l2_entry)) {
1676 case QCOW2_CLUSTER_UNALLOCATED:
1677 if (full_discard || !bs->backing) {
1678 continue;
1679 }
1680 break;
1681
1682 case QCOW2_CLUSTER_ZERO_PLAIN:
1683 if (!full_discard) {
1684 continue;
1685 }
1686 break;
1687
1688 case QCOW2_CLUSTER_ZERO_ALLOC:
1689 case QCOW2_CLUSTER_NORMAL:
1690 case QCOW2_CLUSTER_COMPRESSED:
1691 break;
1692
1693 default:
1694 abort();
1695 }
1696
1697
1698 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
1699 if (!full_discard && s->qcow_version >= 3) {
1700 l2_slice[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
1701 } else {
1702 l2_slice[l2_index + i] = cpu_to_be64(0);
1703 }
1704
1705
1706 qcow2_free_any_clusters(bs, old_l2_entry, 1, type);
1707 }
1708
1709 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1710
1711 return nb_clusters;
1712}
1713
1714int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
1715 uint64_t bytes, enum qcow2_discard_type type,
1716 bool full_discard)
1717{
1718 BDRVQcow2State *s = bs->opaque;
1719 uint64_t end_offset = offset + bytes;
1720 uint64_t nb_clusters;
1721 int64_t cleared;
1722 int ret;
1723
1724
1725 assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
1726 assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) ||
1727 end_offset == bs->total_sectors << BDRV_SECTOR_BITS);
1728
1729 nb_clusters = size_to_clusters(s, bytes);
1730
1731 s->cache_discards = true;
1732
1733
1734 while (nb_clusters > 0) {
1735 cleared = discard_in_l2_slice(bs, offset, nb_clusters, type,
1736 full_discard);
1737 if (cleared < 0) {
1738 ret = cleared;
1739 goto fail;
1740 }
1741
1742 nb_clusters -= cleared;
1743 offset += (cleared * s->cluster_size);
1744 }
1745
1746 ret = 0;
1747fail:
1748 s->cache_discards = false;
1749 qcow2_process_discards(bs, ret);
1750
1751 return ret;
1752}
1753
1754
1755
1756
1757
1758
1759static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset,
1760 uint64_t nb_clusters, int flags)
1761{
1762 BDRVQcow2State *s = bs->opaque;
1763 uint64_t *l2_slice;
1764 int l2_index;
1765 int ret;
1766 int i;
1767 bool unmap = !!(flags & BDRV_REQ_MAY_UNMAP);
1768
1769 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
1770 if (ret < 0) {
1771 return ret;
1772 }
1773
1774
1775 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1776 assert(nb_clusters <= INT_MAX);
1777
1778 for (i = 0; i < nb_clusters; i++) {
1779 uint64_t old_offset;
1780 QCow2ClusterType cluster_type;
1781
1782 old_offset = be64_to_cpu(l2_slice[l2_index + i]);
1783
1784
1785
1786
1787
1788 cluster_type = qcow2_get_cluster_type(old_offset);
1789 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN ||
1790 (cluster_type == QCOW2_CLUSTER_ZERO_ALLOC && !unmap)) {
1791 continue;
1792 }
1793
1794 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
1795 if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) {
1796 l2_slice[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
1797 qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST);
1798 } else {
1799 l2_slice[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO);
1800 }
1801 }
1802
1803 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1804
1805 return nb_clusters;
1806}
1807
1808int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
1809 uint64_t bytes, int flags)
1810{
1811 BDRVQcow2State *s = bs->opaque;
1812 uint64_t end_offset = offset + bytes;
1813 uint64_t nb_clusters;
1814 int64_t cleared;
1815 int ret;
1816
1817
1818 assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
1819 assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) ||
1820 end_offset == bs->total_sectors << BDRV_SECTOR_BITS);
1821
1822
1823 if (s->qcow_version < 3) {
1824 return -ENOTSUP;
1825 }
1826
1827
1828 nb_clusters = size_to_clusters(s, bytes);
1829
1830 s->cache_discards = true;
1831
1832 while (nb_clusters > 0) {
1833 cleared = zero_in_l2_slice(bs, offset, nb_clusters, flags);
1834 if (cleared < 0) {
1835 ret = cleared;
1836 goto fail;
1837 }
1838
1839 nb_clusters -= cleared;
1840 offset += (cleared * s->cluster_size);
1841 }
1842
1843 ret = 0;
1844fail:
1845 s->cache_discards = false;
1846 qcow2_process_discards(bs, ret);
1847
1848 return ret;
1849}
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
1860 int l1_size, int64_t *visited_l1_entries,
1861 int64_t l1_entries,
1862 BlockDriverAmendStatusCB *status_cb,
1863 void *cb_opaque)
1864{
1865 BDRVQcow2State *s = bs->opaque;
1866 bool is_active_l1 = (l1_table == s->l1_table);
1867 uint64_t *l2_slice = NULL;
1868 unsigned slice, slice_size2, n_slices;
1869 int ret;
1870 int i, j;
1871
1872 slice_size2 = s->l2_slice_size * sizeof(uint64_t);
1873 n_slices = s->cluster_size / slice_size2;
1874
1875 if (!is_active_l1) {
1876
1877
1878 l2_slice = qemu_try_blockalign(bs->file->bs, slice_size2);
1879 if (l2_slice == NULL) {
1880 return -ENOMEM;
1881 }
1882 }
1883
1884 for (i = 0; i < l1_size; i++) {
1885 uint64_t l2_offset = l1_table[i] & L1E_OFFSET_MASK;
1886 uint64_t l2_refcount;
1887
1888 if (!l2_offset) {
1889
1890 (*visited_l1_entries)++;
1891 if (status_cb) {
1892 status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque);
1893 }
1894 continue;
1895 }
1896
1897 if (offset_into_cluster(s, l2_offset)) {
1898 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#"
1899 PRIx64 " unaligned (L1 index: %#x)",
1900 l2_offset, i);
1901 ret = -EIO;
1902 goto fail;
1903 }
1904
1905 ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits,
1906 &l2_refcount);
1907 if (ret < 0) {
1908 goto fail;
1909 }
1910
1911 for (slice = 0; slice < n_slices; slice++) {
1912 uint64_t slice_offset = l2_offset + slice * slice_size2;
1913 bool l2_dirty = false;
1914 if (is_active_l1) {
1915
1916 ret = qcow2_cache_get(bs, s->l2_table_cache, slice_offset,
1917 (void **)&l2_slice);
1918 } else {
1919
1920 ret = bdrv_pread(bs->file, slice_offset, l2_slice, slice_size2);
1921 }
1922 if (ret < 0) {
1923 goto fail;
1924 }
1925
1926 for (j = 0; j < s->l2_slice_size; j++) {
1927 uint64_t l2_entry = be64_to_cpu(l2_slice[j]);
1928 int64_t offset = l2_entry & L2E_OFFSET_MASK;
1929 QCow2ClusterType cluster_type =
1930 qcow2_get_cluster_type(l2_entry);
1931
1932 if (cluster_type != QCOW2_CLUSTER_ZERO_PLAIN &&
1933 cluster_type != QCOW2_CLUSTER_ZERO_ALLOC) {
1934 continue;
1935 }
1936
1937 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1938 if (!bs->backing) {
1939
1940
1941 l2_slice[j] = 0;
1942 l2_dirty = true;
1943 continue;
1944 }
1945
1946 offset = qcow2_alloc_clusters(bs, s->cluster_size);
1947 if (offset < 0) {
1948 ret = offset;
1949 goto fail;
1950 }
1951
1952 if (l2_refcount > 1) {
1953
1954
1955 ret = qcow2_update_cluster_refcount(
1956 bs, offset >> s->cluster_bits,
1957 refcount_diff(1, l2_refcount), false,
1958 QCOW2_DISCARD_OTHER);
1959 if (ret < 0) {
1960 qcow2_free_clusters(bs, offset, s->cluster_size,
1961 QCOW2_DISCARD_OTHER);
1962 goto fail;
1963 }
1964 }
1965 }
1966
1967 if (offset_into_cluster(s, offset)) {
1968 int l2_index = slice * s->l2_slice_size + j;
1969 qcow2_signal_corruption(
1970 bs, true, -1, -1,
1971 "Cluster allocation offset "
1972 "%#" PRIx64 " unaligned (L2 offset: %#"
1973 PRIx64 ", L2 index: %#x)", offset,
1974 l2_offset, l2_index);
1975 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1976 qcow2_free_clusters(bs, offset, s->cluster_size,
1977 QCOW2_DISCARD_ALWAYS);
1978 }
1979 ret = -EIO;
1980 goto fail;
1981 }
1982
1983 ret = qcow2_pre_write_overlap_check(bs, 0, offset,
1984 s->cluster_size);
1985 if (ret < 0) {
1986 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1987 qcow2_free_clusters(bs, offset, s->cluster_size,
1988 QCOW2_DISCARD_ALWAYS);
1989 }
1990 goto fail;
1991 }
1992
1993 ret = bdrv_pwrite_zeroes(bs->file, offset, s->cluster_size, 0);
1994 if (ret < 0) {
1995 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
1996 qcow2_free_clusters(bs, offset, s->cluster_size,
1997 QCOW2_DISCARD_ALWAYS);
1998 }
1999 goto fail;
2000 }
2001
2002 if (l2_refcount == 1) {
2003 l2_slice[j] = cpu_to_be64(offset | QCOW_OFLAG_COPIED);
2004 } else {
2005 l2_slice[j] = cpu_to_be64(offset);
2006 }
2007 l2_dirty = true;
2008 }
2009
2010 if (is_active_l1) {
2011 if (l2_dirty) {
2012 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
2013 qcow2_cache_depends_on_flush(s->l2_table_cache);
2014 }
2015 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2016 } else {
2017 if (l2_dirty) {
2018 ret = qcow2_pre_write_overlap_check(
2019 bs, QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2,
2020 slice_offset, slice_size2);
2021 if (ret < 0) {
2022 goto fail;
2023 }
2024
2025 ret = bdrv_pwrite(bs->file, slice_offset,
2026 l2_slice, slice_size2);
2027 if (ret < 0) {
2028 goto fail;
2029 }
2030 }
2031 }
2032 }
2033
2034 (*visited_l1_entries)++;
2035 if (status_cb) {
2036 status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque);
2037 }
2038 }
2039
2040 ret = 0;
2041
2042fail:
2043 if (l2_slice) {
2044 if (!is_active_l1) {
2045 qemu_vfree(l2_slice);
2046 } else {
2047 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2048 }
2049 }
2050 return ret;
2051}
2052
2053
2054
2055
2056
2057
2058
2059int qcow2_expand_zero_clusters(BlockDriverState *bs,
2060 BlockDriverAmendStatusCB *status_cb,
2061 void *cb_opaque)
2062{
2063 BDRVQcow2State *s = bs->opaque;
2064 uint64_t *l1_table = NULL;
2065 int64_t l1_entries = 0, visited_l1_entries = 0;
2066 int ret;
2067 int i, j;
2068
2069 if (status_cb) {
2070 l1_entries = s->l1_size;
2071 for (i = 0; i < s->nb_snapshots; i++) {
2072 l1_entries += s->snapshots[i].l1_size;
2073 }
2074 }
2075
2076 ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size,
2077 &visited_l1_entries, l1_entries,
2078 status_cb, cb_opaque);
2079 if (ret < 0) {
2080 goto fail;
2081 }
2082
2083
2084
2085
2086
2087
2088
2089
2090 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2091 if (ret < 0) {
2092 goto fail;
2093 }
2094
2095 for (i = 0; i < s->nb_snapshots; i++) {
2096 int l1_size2;
2097 uint64_t *new_l1_table;
2098 Error *local_err = NULL;
2099
2100 ret = qcow2_validate_table(bs, s->snapshots[i].l1_table_offset,
2101 s->snapshots[i].l1_size, sizeof(uint64_t),
2102 QCOW_MAX_L1_SIZE, "Snapshot L1 table",
2103 &local_err);
2104 if (ret < 0) {
2105 error_report_err(local_err);
2106 goto fail;
2107 }
2108
2109 l1_size2 = s->snapshots[i].l1_size * sizeof(uint64_t);
2110 new_l1_table = g_try_realloc(l1_table, l1_size2);
2111
2112 if (!new_l1_table) {
2113 ret = -ENOMEM;
2114 goto fail;
2115 }
2116
2117 l1_table = new_l1_table;
2118
2119 ret = bdrv_pread(bs->file, s->snapshots[i].l1_table_offset,
2120 l1_table, l1_size2);
2121 if (ret < 0) {
2122 goto fail;
2123 }
2124
2125 for (j = 0; j < s->snapshots[i].l1_size; j++) {
2126 be64_to_cpus(&l1_table[j]);
2127 }
2128
2129 ret = expand_zero_clusters_in_l1(bs, l1_table, s->snapshots[i].l1_size,
2130 &visited_l1_entries, l1_entries,
2131 status_cb, cb_opaque);
2132 if (ret < 0) {
2133 goto fail;
2134 }
2135 }
2136
2137 ret = 0;
2138
2139fail:
2140 g_free(l1_table);
2141 return ret;
2142}
2143