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25#include "qemu/osdep.h"
26#include <zlib.h>
27
28#include "qapi/error.h"
29#include "qcow2.h"
30#include "qemu/bswap.h"
31#include "trace.h"
32
33int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t exact_size)
34{
35 BDRVQcow2State *s = bs->opaque;
36 int new_l1_size, i, ret;
37
38 if (exact_size >= s->l1_size) {
39 return 0;
40 }
41
42 new_l1_size = exact_size;
43
44#ifdef DEBUG_ALLOC2
45 fprintf(stderr, "shrink l1_table from %d to %d\n", s->l1_size, new_l1_size);
46#endif
47
48 BLKDBG_EVENT(bs->file, BLKDBG_L1_SHRINK_WRITE_TABLE);
49 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset +
50 new_l1_size * L1E_SIZE,
51 (s->l1_size - new_l1_size) * L1E_SIZE, 0);
52 if (ret < 0) {
53 goto fail;
54 }
55
56 ret = bdrv_flush(bs->file->bs);
57 if (ret < 0) {
58 goto fail;
59 }
60
61 BLKDBG_EVENT(bs->file, BLKDBG_L1_SHRINK_FREE_L2_CLUSTERS);
62 for (i = s->l1_size - 1; i > new_l1_size - 1; i--) {
63 if ((s->l1_table[i] & L1E_OFFSET_MASK) == 0) {
64 continue;
65 }
66 qcow2_free_clusters(bs, s->l1_table[i] & L1E_OFFSET_MASK,
67 s->cluster_size, QCOW2_DISCARD_ALWAYS);
68 s->l1_table[i] = 0;
69 }
70 return 0;
71
72fail:
73
74
75
76
77
78 memset(s->l1_table + new_l1_size, 0,
79 (s->l1_size - new_l1_size) * L1E_SIZE);
80 return ret;
81}
82
83int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
84 bool exact_size)
85{
86 BDRVQcow2State *s = bs->opaque;
87 int new_l1_size2, ret, i;
88 uint64_t *new_l1_table;
89 int64_t old_l1_table_offset, old_l1_size;
90 int64_t new_l1_table_offset, new_l1_size;
91 uint8_t data[12];
92
93 if (min_size <= s->l1_size)
94 return 0;
95
96
97
98
99 if (min_size > INT_MAX / L1E_SIZE) {
100 return -EFBIG;
101 }
102
103 if (exact_size) {
104 new_l1_size = min_size;
105 } else {
106
107 new_l1_size = s->l1_size;
108 if (new_l1_size == 0) {
109 new_l1_size = 1;
110 }
111 while (min_size > new_l1_size) {
112 new_l1_size = DIV_ROUND_UP(new_l1_size * 3, 2);
113 }
114 }
115
116 QEMU_BUILD_BUG_ON(QCOW_MAX_L1_SIZE > INT_MAX);
117 if (new_l1_size > QCOW_MAX_L1_SIZE / L1E_SIZE) {
118 return -EFBIG;
119 }
120
121#ifdef DEBUG_ALLOC2
122 fprintf(stderr, "grow l1_table from %d to %" PRId64 "\n",
123 s->l1_size, new_l1_size);
124#endif
125
126 new_l1_size2 = L1E_SIZE * new_l1_size;
127 new_l1_table = qemu_try_blockalign(bs->file->bs, new_l1_size2);
128 if (new_l1_table == NULL) {
129 return -ENOMEM;
130 }
131 memset(new_l1_table, 0, new_l1_size2);
132
133 if (s->l1_size) {
134 memcpy(new_l1_table, s->l1_table, s->l1_size * L1E_SIZE);
135 }
136
137
138 BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
139 new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
140 if (new_l1_table_offset < 0) {
141 qemu_vfree(new_l1_table);
142 return new_l1_table_offset;
143 }
144
145 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
146 if (ret < 0) {
147 goto fail;
148 }
149
150
151
152 ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset,
153 new_l1_size2, false);
154 if (ret < 0) {
155 goto fail;
156 }
157
158 BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE);
159 for(i = 0; i < s->l1_size; i++)
160 new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
161 ret = bdrv_pwrite_sync(bs->file, new_l1_table_offset,
162 new_l1_table, new_l1_size2);
163 if (ret < 0)
164 goto fail;
165 for(i = 0; i < s->l1_size; i++)
166 new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
167
168
169 BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ACTIVATE_TABLE);
170 stl_be_p(data, new_l1_size);
171 stq_be_p(data + 4, new_l1_table_offset);
172 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_size),
173 data, sizeof(data));
174 if (ret < 0) {
175 goto fail;
176 }
177 qemu_vfree(s->l1_table);
178 old_l1_table_offset = s->l1_table_offset;
179 s->l1_table_offset = new_l1_table_offset;
180 s->l1_table = new_l1_table;
181 old_l1_size = s->l1_size;
182 s->l1_size = new_l1_size;
183 qcow2_free_clusters(bs, old_l1_table_offset, old_l1_size * L1E_SIZE,
184 QCOW2_DISCARD_OTHER);
185 return 0;
186 fail:
187 qemu_vfree(new_l1_table);
188 qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2,
189 QCOW2_DISCARD_OTHER);
190 return ret;
191}
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206
207static int l2_load(BlockDriverState *bs, uint64_t offset,
208 uint64_t l2_offset, uint64_t **l2_slice)
209{
210 BDRVQcow2State *s = bs->opaque;
211 int start_of_slice = l2_entry_size(s) *
212 (offset_to_l2_index(s, offset) - offset_to_l2_slice_index(s, offset));
213
214 return qcow2_cache_get(bs, s->l2_table_cache, l2_offset + start_of_slice,
215 (void **)l2_slice);
216}
217
218
219
220
221
222
223int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
224{
225 BDRVQcow2State *s = bs->opaque;
226 int l1_start_index;
227 int i, ret;
228 int bufsize = MAX(L1E_SIZE,
229 MIN(bs->file->bs->bl.request_alignment, s->cluster_size));
230 int nentries = bufsize / L1E_SIZE;
231 g_autofree uint64_t *buf = g_try_new0(uint64_t, nentries);
232
233 if (buf == NULL) {
234 return -ENOMEM;
235 }
236
237 l1_start_index = QEMU_ALIGN_DOWN(l1_index, nentries);
238 for (i = 0; i < MIN(nentries, s->l1_size - l1_start_index); i++) {
239 buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
240 }
241
242 ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
243 s->l1_table_offset + L1E_SIZE * l1_start_index, bufsize, false);
244 if (ret < 0) {
245 return ret;
246 }
247
248 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
249 ret = bdrv_pwrite_sync(bs->file,
250 s->l1_table_offset + L1E_SIZE * l1_start_index,
251 buf, bufsize);
252 if (ret < 0) {
253 return ret;
254 }
255
256 return 0;
257}
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268
269static int l2_allocate(BlockDriverState *bs, int l1_index)
270{
271 BDRVQcow2State *s = bs->opaque;
272 uint64_t old_l2_offset;
273 uint64_t *l2_slice = NULL;
274 unsigned slice, slice_size2, n_slices;
275 int64_t l2_offset;
276 int ret;
277
278 old_l2_offset = s->l1_table[l1_index];
279
280 trace_qcow2_l2_allocate(bs, l1_index);
281
282
283
284 l2_offset = qcow2_alloc_clusters(bs, s->l2_size * l2_entry_size(s));
285 if (l2_offset < 0) {
286 ret = l2_offset;
287 goto fail;
288 }
289
290
291 assert((l2_offset & L1E_OFFSET_MASK) == l2_offset);
292
293
294 if (l2_offset == 0) {
295 qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid "
296 "allocation of L2 table at offset 0");
297 ret = -EIO;
298 goto fail;
299 }
300
301 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
302 if (ret < 0) {
303 goto fail;
304 }
305
306
307
308 slice_size2 = s->l2_slice_size * l2_entry_size(s);
309 n_slices = s->cluster_size / slice_size2;
310
311 trace_qcow2_l2_allocate_get_empty(bs, l1_index);
312 for (slice = 0; slice < n_slices; slice++) {
313 ret = qcow2_cache_get_empty(bs, s->l2_table_cache,
314 l2_offset + slice * slice_size2,
315 (void **) &l2_slice);
316 if (ret < 0) {
317 goto fail;
318 }
319
320 if ((old_l2_offset & L1E_OFFSET_MASK) == 0) {
321
322 memset(l2_slice, 0, slice_size2);
323 } else {
324 uint64_t *old_slice;
325 uint64_t old_l2_slice_offset =
326 (old_l2_offset & L1E_OFFSET_MASK) + slice * slice_size2;
327
328
329 BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
330 ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_slice_offset,
331 (void **) &old_slice);
332 if (ret < 0) {
333 goto fail;
334 }
335
336 memcpy(l2_slice, old_slice, slice_size2);
337
338 qcow2_cache_put(s->l2_table_cache, (void **) &old_slice);
339 }
340
341
342 BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
343
344 trace_qcow2_l2_allocate_write_l2(bs, l1_index);
345 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
346 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
347 }
348
349 ret = qcow2_cache_flush(bs, s->l2_table_cache);
350 if (ret < 0) {
351 goto fail;
352 }
353
354
355 trace_qcow2_l2_allocate_write_l1(bs, l1_index);
356 s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
357 ret = qcow2_write_l1_entry(bs, l1_index);
358 if (ret < 0) {
359 goto fail;
360 }
361
362 trace_qcow2_l2_allocate_done(bs, l1_index, 0);
363 return 0;
364
365fail:
366 trace_qcow2_l2_allocate_done(bs, l1_index, ret);
367 if (l2_slice != NULL) {
368 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
369 }
370 s->l1_table[l1_index] = old_l2_offset;
371 if (l2_offset > 0) {
372 qcow2_free_clusters(bs, l2_offset, s->l2_size * l2_entry_size(s),
373 QCOW2_DISCARD_ALWAYS);
374 }
375 return ret;
376}
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389
390static int qcow2_get_subcluster_range_type(BlockDriverState *bs,
391 uint64_t l2_entry,
392 uint64_t l2_bitmap,
393 unsigned sc_from,
394 QCow2SubclusterType *type)
395{
396 BDRVQcow2State *s = bs->opaque;
397 uint32_t val;
398
399 *type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_from);
400
401 if (*type == QCOW2_SUBCLUSTER_INVALID) {
402 return -EINVAL;
403 } else if (!has_subclusters(s) || *type == QCOW2_SUBCLUSTER_COMPRESSED) {
404 return s->subclusters_per_cluster - sc_from;
405 }
406
407 switch (*type) {
408 case QCOW2_SUBCLUSTER_NORMAL:
409 val = l2_bitmap | QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from);
410 return cto32(val) - sc_from;
411
412 case QCOW2_SUBCLUSTER_ZERO_PLAIN:
413 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
414 val = (l2_bitmap | QCOW_OFLAG_SUB_ZERO_RANGE(0, sc_from)) >> 32;
415 return cto32(val) - sc_from;
416
417 case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
418 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
419 val = ((l2_bitmap >> 32) | l2_bitmap)
420 & ~QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from);
421 return ctz32(val) - sc_from;
422
423 default:
424 g_assert_not_reached();
425 }
426}
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441static int count_contiguous_subclusters(BlockDriverState *bs, int nb_clusters,
442 unsigned sc_index, uint64_t *l2_slice,
443 unsigned *l2_index)
444{
445 BDRVQcow2State *s = bs->opaque;
446 int i, count = 0;
447 bool check_offset = false;
448 uint64_t expected_offset = 0;
449 QCow2SubclusterType expected_type = QCOW2_SUBCLUSTER_NORMAL, type;
450
451 assert(*l2_index + nb_clusters <= s->l2_slice_size);
452
453 for (i = 0; i < nb_clusters; i++) {
454 unsigned first_sc = (i == 0) ? sc_index : 0;
455 uint64_t l2_entry = get_l2_entry(s, l2_slice, *l2_index + i);
456 uint64_t l2_bitmap = get_l2_bitmap(s, l2_slice, *l2_index + i);
457 int ret = qcow2_get_subcluster_range_type(bs, l2_entry, l2_bitmap,
458 first_sc, &type);
459 if (ret < 0) {
460 *l2_index += i;
461 return -EIO;
462 }
463 if (i == 0) {
464 if (type == QCOW2_SUBCLUSTER_COMPRESSED) {
465
466 return ret;
467 }
468 expected_type = type;
469 expected_offset = l2_entry & L2E_OFFSET_MASK;
470 check_offset = (type == QCOW2_SUBCLUSTER_NORMAL ||
471 type == QCOW2_SUBCLUSTER_ZERO_ALLOC ||
472 type == QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC);
473 } else if (type != expected_type) {
474 break;
475 } else if (check_offset) {
476 expected_offset += s->cluster_size;
477 if (expected_offset != (l2_entry & L2E_OFFSET_MASK)) {
478 break;
479 }
480 }
481 count += ret;
482
483 if (first_sc + ret < s->subclusters_per_cluster) {
484 break;
485 }
486 }
487
488 return count;
489}
490
491static int coroutine_fn do_perform_cow_read(BlockDriverState *bs,
492 uint64_t src_cluster_offset,
493 unsigned offset_in_cluster,
494 QEMUIOVector *qiov)
495{
496 int ret;
497
498 if (qiov->size == 0) {
499 return 0;
500 }
501
502 BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
503
504 if (!bs->drv) {
505 return -ENOMEDIUM;
506 }
507
508
509
510
511
512
513
514 assert(src_cluster_offset <= INT64_MAX);
515 assert(src_cluster_offset + offset_in_cluster <= INT64_MAX);
516
517 assert((uint64_t)qiov->size <= INT64_MAX);
518 bdrv_check_qiov_request(src_cluster_offset + offset_in_cluster, qiov->size,
519 qiov, 0, &error_abort);
520
521
522
523
524
525 ret = bs->drv->bdrv_co_preadv_part(bs,
526 src_cluster_offset + offset_in_cluster,
527 qiov->size, qiov, 0, 0);
528 if (ret < 0) {
529 return ret;
530 }
531
532 return 0;
533}
534
535static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,
536 uint64_t cluster_offset,
537 unsigned offset_in_cluster,
538 QEMUIOVector *qiov)
539{
540 BDRVQcow2State *s = bs->opaque;
541 int ret;
542
543 if (qiov->size == 0) {
544 return 0;
545 }
546
547 ret = qcow2_pre_write_overlap_check(bs, 0,
548 cluster_offset + offset_in_cluster, qiov->size, true);
549 if (ret < 0) {
550 return ret;
551 }
552
553 BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
554 ret = bdrv_co_pwritev(s->data_file, cluster_offset + offset_in_cluster,
555 qiov->size, qiov, 0);
556 if (ret < 0) {
557 return ret;
558 }
559
560 return 0;
561}
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583
584int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset,
585 unsigned int *bytes, uint64_t *host_offset,
586 QCow2SubclusterType *subcluster_type)
587{
588 BDRVQcow2State *s = bs->opaque;
589 unsigned int l2_index, sc_index;
590 uint64_t l1_index, l2_offset, *l2_slice, l2_entry, l2_bitmap;
591 int sc;
592 unsigned int offset_in_cluster;
593 uint64_t bytes_available, bytes_needed, nb_clusters;
594 QCow2SubclusterType type;
595 int ret;
596
597 offset_in_cluster = offset_into_cluster(s, offset);
598 bytes_needed = (uint64_t) *bytes + offset_in_cluster;
599
600
601
602
603 bytes_available =
604 ((uint64_t) (s->l2_slice_size - offset_to_l2_slice_index(s, offset)))
605 << s->cluster_bits;
606
607 if (bytes_needed > bytes_available) {
608 bytes_needed = bytes_available;
609 }
610
611 *host_offset = 0;
612
613
614
615 l1_index = offset_to_l1_index(s, offset);
616 if (l1_index >= s->l1_size) {
617 type = QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN;
618 goto out;
619 }
620
621 l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
622 if (!l2_offset) {
623 type = QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN;
624 goto out;
625 }
626
627 if (offset_into_cluster(s, l2_offset)) {
628 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64
629 " unaligned (L1 index: %#" PRIx64 ")",
630 l2_offset, l1_index);
631 return -EIO;
632 }
633
634
635
636 ret = l2_load(bs, offset, l2_offset, &l2_slice);
637 if (ret < 0) {
638 return ret;
639 }
640
641
642
643 l2_index = offset_to_l2_slice_index(s, offset);
644 sc_index = offset_to_sc_index(s, offset);
645 l2_entry = get_l2_entry(s, l2_slice, l2_index);
646 l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index);
647
648 nb_clusters = size_to_clusters(s, bytes_needed);
649
650
651
652 assert(nb_clusters <= INT_MAX);
653
654 type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index);
655 if (s->qcow_version < 3 && (type == QCOW2_SUBCLUSTER_ZERO_PLAIN ||
656 type == QCOW2_SUBCLUSTER_ZERO_ALLOC)) {
657 qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry found"
658 " in pre-v3 image (L2 offset: %#" PRIx64
659 ", L2 index: %#x)", l2_offset, l2_index);
660 ret = -EIO;
661 goto fail;
662 }
663 switch (type) {
664 case QCOW2_SUBCLUSTER_INVALID:
665 break;
666 case QCOW2_SUBCLUSTER_COMPRESSED:
667 if (has_data_file(bs)) {
668 qcow2_signal_corruption(bs, true, -1, -1, "Compressed cluster "
669 "entry found in image with external data "
670 "file (L2 offset: %#" PRIx64 ", L2 index: "
671 "%#x)", l2_offset, l2_index);
672 ret = -EIO;
673 goto fail;
674 }
675 *host_offset = l2_entry;
676 break;
677 case QCOW2_SUBCLUSTER_ZERO_PLAIN:
678 case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
679 break;
680 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
681 case QCOW2_SUBCLUSTER_NORMAL:
682 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: {
683 uint64_t host_cluster_offset = l2_entry & L2E_OFFSET_MASK;
684 *host_offset = host_cluster_offset + offset_in_cluster;
685 if (offset_into_cluster(s, host_cluster_offset)) {
686 qcow2_signal_corruption(bs, true, -1, -1,
687 "Cluster allocation offset %#"
688 PRIx64 " unaligned (L2 offset: %#" PRIx64
689 ", L2 index: %#x)", host_cluster_offset,
690 l2_offset, l2_index);
691 ret = -EIO;
692 goto fail;
693 }
694 if (has_data_file(bs) && *host_offset != offset) {
695 qcow2_signal_corruption(bs, true, -1, -1,
696 "External data file host cluster offset %#"
697 PRIx64 " does not match guest cluster "
698 "offset: %#" PRIx64
699 ", L2 index: %#x)", host_cluster_offset,
700 offset - offset_in_cluster, l2_index);
701 ret = -EIO;
702 goto fail;
703 }
704 break;
705 }
706 default:
707 abort();
708 }
709
710 sc = count_contiguous_subclusters(bs, nb_clusters, sc_index,
711 l2_slice, &l2_index);
712 if (sc < 0) {
713 qcow2_signal_corruption(bs, true, -1, -1, "Invalid cluster entry found "
714 " (L2 offset: %#" PRIx64 ", L2 index: %#x)",
715 l2_offset, l2_index);
716 ret = -EIO;
717 goto fail;
718 }
719 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
720
721 bytes_available = ((int64_t)sc + sc_index) << s->subcluster_bits;
722
723out:
724 if (bytes_available > bytes_needed) {
725 bytes_available = bytes_needed;
726 }
727
728
729
730
731 assert(bytes_available - offset_in_cluster <= UINT_MAX);
732 *bytes = bytes_available - offset_in_cluster;
733
734 *subcluster_type = type;
735
736 return 0;
737
738fail:
739 qcow2_cache_put(s->l2_table_cache, (void **)&l2_slice);
740 return ret;
741}
742
743
744
745
746
747
748
749
750
751
752
753static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
754 uint64_t **new_l2_slice,
755 int *new_l2_index)
756{
757 BDRVQcow2State *s = bs->opaque;
758 unsigned int l2_index;
759 uint64_t l1_index, l2_offset;
760 uint64_t *l2_slice = NULL;
761 int ret;
762
763
764
765 l1_index = offset_to_l1_index(s, offset);
766 if (l1_index >= s->l1_size) {
767 ret = qcow2_grow_l1_table(bs, l1_index + 1, false);
768 if (ret < 0) {
769 return ret;
770 }
771 }
772
773 assert(l1_index < s->l1_size);
774 l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
775 if (offset_into_cluster(s, l2_offset)) {
776 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#" PRIx64
777 " unaligned (L1 index: %#" PRIx64 ")",
778 l2_offset, l1_index);
779 return -EIO;
780 }
781
782 if (!(s->l1_table[l1_index] & QCOW_OFLAG_COPIED)) {
783
784 ret = l2_allocate(bs, l1_index);
785 if (ret < 0) {
786 return ret;
787 }
788
789
790 if (l2_offset) {
791 qcow2_free_clusters(bs, l2_offset, s->l2_size * l2_entry_size(s),
792 QCOW2_DISCARD_OTHER);
793 }
794
795
796 l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
797 assert(offset_into_cluster(s, l2_offset) == 0);
798 }
799
800
801 ret = l2_load(bs, offset, l2_offset, &l2_slice);
802 if (ret < 0) {
803 return ret;
804 }
805
806
807
808 l2_index = offset_to_l2_slice_index(s, offset);
809
810 *new_l2_slice = l2_slice;
811 *new_l2_index = l2_index;
812
813 return 0;
814}
815
816
817
818
819
820
821
822
823
824
825int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
826 uint64_t offset,
827 int compressed_size,
828 uint64_t *host_offset)
829{
830 BDRVQcow2State *s = bs->opaque;
831 int l2_index, ret;
832 uint64_t *l2_slice;
833 int64_t cluster_offset;
834 int nb_csectors;
835
836 if (has_data_file(bs)) {
837 return 0;
838 }
839
840 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
841 if (ret < 0) {
842 return ret;
843 }
844
845
846
847 cluster_offset = get_l2_entry(s, l2_slice, l2_index);
848 if (cluster_offset & L2E_OFFSET_MASK) {
849 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
850 return -EIO;
851 }
852
853 cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
854 if (cluster_offset < 0) {
855 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
856 return cluster_offset;
857 }
858
859 nb_csectors =
860 (cluster_offset + compressed_size - 1) / QCOW2_COMPRESSED_SECTOR_SIZE -
861 (cluster_offset / QCOW2_COMPRESSED_SECTOR_SIZE);
862
863
864 assert((cluster_offset & s->cluster_offset_mask) == cluster_offset);
865 assert((nb_csectors & s->csize_mask) == nb_csectors);
866
867 cluster_offset |= QCOW_OFLAG_COMPRESSED |
868 ((uint64_t)nb_csectors << s->csize_shift);
869
870
871
872
873
874 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
875 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
876 set_l2_entry(s, l2_slice, l2_index, cluster_offset);
877 if (has_subclusters(s)) {
878 set_l2_bitmap(s, l2_slice, l2_index, 0);
879 }
880 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
881
882 *host_offset = cluster_offset & s->cluster_offset_mask;
883 return 0;
884}
885
886static int perform_cow(BlockDriverState *bs, QCowL2Meta *m)
887{
888 BDRVQcow2State *s = bs->opaque;
889 Qcow2COWRegion *start = &m->cow_start;
890 Qcow2COWRegion *end = &m->cow_end;
891 unsigned buffer_size;
892 unsigned data_bytes = end->offset - (start->offset + start->nb_bytes);
893 bool merge_reads;
894 uint8_t *start_buffer, *end_buffer;
895 QEMUIOVector qiov;
896 int ret;
897
898 assert(start->nb_bytes <= UINT_MAX - end->nb_bytes);
899 assert(start->nb_bytes + end->nb_bytes <= UINT_MAX - data_bytes);
900 assert(start->offset + start->nb_bytes <= end->offset);
901
902 if ((start->nb_bytes == 0 && end->nb_bytes == 0) || m->skip_cow) {
903 return 0;
904 }
905
906
907
908
909 merge_reads = start->nb_bytes && end->nb_bytes && data_bytes <= 16384;
910 if (merge_reads) {
911 buffer_size = start->nb_bytes + data_bytes + end->nb_bytes;
912 } else {
913
914
915
916 size_t align = bdrv_opt_mem_align(bs);
917 assert(align > 0 && align <= UINT_MAX);
918 assert(QEMU_ALIGN_UP(start->nb_bytes, align) <=
919 UINT_MAX - end->nb_bytes);
920 buffer_size = QEMU_ALIGN_UP(start->nb_bytes, align) + end->nb_bytes;
921 }
922
923
924
925 start_buffer = qemu_try_blockalign(bs, buffer_size);
926 if (start_buffer == NULL) {
927 return -ENOMEM;
928 }
929
930 end_buffer = start_buffer + buffer_size - end->nb_bytes;
931
932 qemu_iovec_init(&qiov, 2 + (m->data_qiov ?
933 qemu_iovec_subvec_niov(m->data_qiov,
934 m->data_qiov_offset,
935 data_bytes)
936 : 0));
937
938 qemu_co_mutex_unlock(&s->lock);
939
940
941
942 if (merge_reads) {
943 qemu_iovec_add(&qiov, start_buffer, buffer_size);
944 ret = do_perform_cow_read(bs, m->offset, start->offset, &qiov);
945 } else {
946 qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
947 ret = do_perform_cow_read(bs, m->offset, start->offset, &qiov);
948 if (ret < 0) {
949 goto fail;
950 }
951
952 qemu_iovec_reset(&qiov);
953 qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
954 ret = do_perform_cow_read(bs, m->offset, end->offset, &qiov);
955 }
956 if (ret < 0) {
957 goto fail;
958 }
959
960
961 if (bs->encrypted) {
962 ret = qcow2_co_encrypt(bs,
963 m->alloc_offset + start->offset,
964 m->offset + start->offset,
965 start_buffer, start->nb_bytes);
966 if (ret < 0) {
967 goto fail;
968 }
969
970 ret = qcow2_co_encrypt(bs,
971 m->alloc_offset + end->offset,
972 m->offset + end->offset,
973 end_buffer, end->nb_bytes);
974 if (ret < 0) {
975 goto fail;
976 }
977 }
978
979
980
981 if (m->data_qiov) {
982 qemu_iovec_reset(&qiov);
983 if (start->nb_bytes) {
984 qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
985 }
986 qemu_iovec_concat(&qiov, m->data_qiov, m->data_qiov_offset, data_bytes);
987 if (end->nb_bytes) {
988 qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
989 }
990
991
992
993 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
994 ret = do_perform_cow_write(bs, m->alloc_offset, start->offset, &qiov);
995 } else {
996
997 qemu_iovec_reset(&qiov);
998 qemu_iovec_add(&qiov, start_buffer, start->nb_bytes);
999 ret = do_perform_cow_write(bs, m->alloc_offset, start->offset, &qiov);
1000 if (ret < 0) {
1001 goto fail;
1002 }
1003
1004 qemu_iovec_reset(&qiov);
1005 qemu_iovec_add(&qiov, end_buffer, end->nb_bytes);
1006 ret = do_perform_cow_write(bs, m->alloc_offset, end->offset, &qiov);
1007 }
1008
1009fail:
1010 qemu_co_mutex_lock(&s->lock);
1011
1012
1013
1014
1015
1016
1017 if (ret == 0) {
1018 qcow2_cache_depends_on_flush(s->l2_table_cache);
1019 }
1020
1021 qemu_vfree(start_buffer);
1022 qemu_iovec_destroy(&qiov);
1023 return ret;
1024}
1025
1026int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
1027{
1028 BDRVQcow2State *s = bs->opaque;
1029 int i, j = 0, l2_index, ret;
1030 uint64_t *old_cluster, *l2_slice;
1031 uint64_t cluster_offset = m->alloc_offset;
1032
1033 trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
1034 assert(m->nb_clusters > 0);
1035
1036 old_cluster = g_try_new(uint64_t, m->nb_clusters);
1037 if (old_cluster == NULL) {
1038 ret = -ENOMEM;
1039 goto err;
1040 }
1041
1042
1043 ret = perform_cow(bs, m);
1044 if (ret < 0) {
1045 goto err;
1046 }
1047
1048
1049 if (s->use_lazy_refcounts) {
1050 qcow2_mark_dirty(bs);
1051 }
1052 if (qcow2_need_accurate_refcounts(s)) {
1053 qcow2_cache_set_dependency(bs, s->l2_table_cache,
1054 s->refcount_block_cache);
1055 }
1056
1057 ret = get_cluster_table(bs, m->offset, &l2_slice, &l2_index);
1058 if (ret < 0) {
1059 goto err;
1060 }
1061 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
1062
1063 assert(l2_index + m->nb_clusters <= s->l2_slice_size);
1064 assert(m->cow_end.offset + m->cow_end.nb_bytes <=
1065 m->nb_clusters << s->cluster_bits);
1066 for (i = 0; i < m->nb_clusters; i++) {
1067 uint64_t offset = cluster_offset + ((uint64_t)i << s->cluster_bits);
1068
1069
1070
1071
1072
1073
1074 if (get_l2_entry(s, l2_slice, l2_index + i) != 0) {
1075 old_cluster[j++] = get_l2_entry(s, l2_slice, l2_index + i);
1076 }
1077
1078
1079 assert((offset & L2E_OFFSET_MASK) == offset);
1080
1081 set_l2_entry(s, l2_slice, l2_index + i, offset | QCOW_OFLAG_COPIED);
1082
1083
1084 if (has_subclusters(s) && !m->prealloc) {
1085 uint64_t l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i);
1086 unsigned written_from = m->cow_start.offset;
1087 unsigned written_to = m->cow_end.offset + m->cow_end.nb_bytes;
1088 int first_sc, last_sc;
1089
1090 written_from = MAX(written_from, i << s->cluster_bits);
1091 written_to = MIN(written_to, (i + 1) << s->cluster_bits);
1092 assert(written_from < written_to);
1093 first_sc = offset_to_sc_index(s, written_from);
1094 last_sc = offset_to_sc_index(s, written_to - 1);
1095 l2_bitmap |= QCOW_OFLAG_SUB_ALLOC_RANGE(first_sc, last_sc + 1);
1096 l2_bitmap &= ~QCOW_OFLAG_SUB_ZERO_RANGE(first_sc, last_sc + 1);
1097 set_l2_bitmap(s, l2_slice, l2_index + i, l2_bitmap);
1098 }
1099 }
1100
1101
1102 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1103
1104
1105
1106
1107
1108
1109
1110 if (!m->keep_old_clusters && j != 0) {
1111 for (i = 0; i < j; i++) {
1112 qcow2_free_any_cluster(bs, old_cluster[i], QCOW2_DISCARD_NEVER);
1113 }
1114 }
1115
1116 ret = 0;
1117err:
1118 g_free(old_cluster);
1119 return ret;
1120 }
1121
1122
1123
1124
1125
1126void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m)
1127{
1128 BDRVQcow2State *s = bs->opaque;
1129 if (!has_data_file(bs) && !m->keep_old_clusters) {
1130 qcow2_free_clusters(bs, m->alloc_offset,
1131 m->nb_clusters << s->cluster_bits,
1132 QCOW2_DISCARD_NEVER);
1133 }
1134}
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156static int calculate_l2_meta(BlockDriverState *bs, uint64_t host_cluster_offset,
1157 uint64_t guest_offset, unsigned bytes,
1158 uint64_t *l2_slice, QCowL2Meta **m, bool keep_old)
1159{
1160 BDRVQcow2State *s = bs->opaque;
1161 int sc_index, l2_index = offset_to_l2_slice_index(s, guest_offset);
1162 uint64_t l2_entry, l2_bitmap;
1163 unsigned cow_start_from, cow_end_to;
1164 unsigned cow_start_to = offset_into_cluster(s, guest_offset);
1165 unsigned cow_end_from = cow_start_to + bytes;
1166 unsigned nb_clusters = size_to_clusters(s, cow_end_from);
1167 QCowL2Meta *old_m = *m;
1168 QCow2SubclusterType type;
1169 int i;
1170 bool skip_cow = keep_old;
1171
1172 assert(nb_clusters <= s->l2_slice_size - l2_index);
1173
1174
1175 for (i = 0; i < nb_clusters; i++) {
1176 l2_entry = get_l2_entry(s, l2_slice, l2_index + i);
1177 l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i);
1178 if (skip_cow) {
1179 unsigned write_from = MAX(cow_start_to, i << s->cluster_bits);
1180 unsigned write_to = MIN(cow_end_from, (i + 1) << s->cluster_bits);
1181 int first_sc = offset_to_sc_index(s, write_from);
1182 int last_sc = offset_to_sc_index(s, write_to - 1);
1183 int cnt = qcow2_get_subcluster_range_type(bs, l2_entry, l2_bitmap,
1184 first_sc, &type);
1185
1186 if (type != QCOW2_SUBCLUSTER_NORMAL || first_sc + cnt <= last_sc) {
1187 skip_cow = false;
1188 }
1189 } else {
1190
1191 type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, 0);
1192 }
1193 if (type == QCOW2_SUBCLUSTER_INVALID) {
1194 int l1_index = offset_to_l1_index(s, guest_offset);
1195 uint64_t l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
1196 qcow2_signal_corruption(bs, true, -1, -1, "Invalid cluster "
1197 "entry found (L2 offset: %#" PRIx64
1198 ", L2 index: %#x)",
1199 l2_offset, l2_index + i);
1200 return -EIO;
1201 }
1202 }
1203
1204 if (skip_cow) {
1205 return 0;
1206 }
1207
1208
1209 l2_entry = get_l2_entry(s, l2_slice, l2_index);
1210 l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index);
1211 sc_index = offset_to_sc_index(s, guest_offset);
1212 type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index);
1213
1214 if (!keep_old) {
1215 switch (type) {
1216 case QCOW2_SUBCLUSTER_COMPRESSED:
1217 cow_start_from = 0;
1218 break;
1219 case QCOW2_SUBCLUSTER_NORMAL:
1220 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
1221 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
1222 if (has_subclusters(s)) {
1223
1224 uint32_t alloc_bitmap = l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC;
1225 cow_start_from =
1226 MIN(sc_index, ctz32(alloc_bitmap)) << s->subcluster_bits;
1227 } else {
1228 cow_start_from = 0;
1229 }
1230 break;
1231 case QCOW2_SUBCLUSTER_ZERO_PLAIN:
1232 case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
1233 cow_start_from = sc_index << s->subcluster_bits;
1234 break;
1235 default:
1236 g_assert_not_reached();
1237 }
1238 } else {
1239 switch (type) {
1240 case QCOW2_SUBCLUSTER_NORMAL:
1241 cow_start_from = cow_start_to;
1242 break;
1243 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
1244 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
1245 cow_start_from = sc_index << s->subcluster_bits;
1246 break;
1247 default:
1248 g_assert_not_reached();
1249 }
1250 }
1251
1252
1253 l2_index += nb_clusters - 1;
1254 l2_entry = get_l2_entry(s, l2_slice, l2_index);
1255 l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index);
1256 sc_index = offset_to_sc_index(s, guest_offset + bytes - 1);
1257 type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index);
1258
1259 if (!keep_old) {
1260 switch (type) {
1261 case QCOW2_SUBCLUSTER_COMPRESSED:
1262 cow_end_to = ROUND_UP(cow_end_from, s->cluster_size);
1263 break;
1264 case QCOW2_SUBCLUSTER_NORMAL:
1265 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
1266 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
1267 cow_end_to = ROUND_UP(cow_end_from, s->cluster_size);
1268 if (has_subclusters(s)) {
1269
1270 uint32_t alloc_bitmap = l2_bitmap & QCOW_L2_BITMAP_ALL_ALLOC;
1271 cow_end_to -=
1272 MIN(s->subclusters_per_cluster - sc_index - 1,
1273 clz32(alloc_bitmap)) << s->subcluster_bits;
1274 }
1275 break;
1276 case QCOW2_SUBCLUSTER_ZERO_PLAIN:
1277 case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
1278 cow_end_to = ROUND_UP(cow_end_from, s->subcluster_size);
1279 break;
1280 default:
1281 g_assert_not_reached();
1282 }
1283 } else {
1284 switch (type) {
1285 case QCOW2_SUBCLUSTER_NORMAL:
1286 cow_end_to = cow_end_from;
1287 break;
1288 case QCOW2_SUBCLUSTER_ZERO_ALLOC:
1289 case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
1290 cow_end_to = ROUND_UP(cow_end_from, s->subcluster_size);
1291 break;
1292 default:
1293 g_assert_not_reached();
1294 }
1295 }
1296
1297 *m = g_malloc0(sizeof(**m));
1298 **m = (QCowL2Meta) {
1299 .next = old_m,
1300
1301 .alloc_offset = host_cluster_offset,
1302 .offset = start_of_cluster(s, guest_offset),
1303 .nb_clusters = nb_clusters,
1304
1305 .keep_old_clusters = keep_old,
1306
1307 .cow_start = {
1308 .offset = cow_start_from,
1309 .nb_bytes = cow_start_to - cow_start_from,
1310 },
1311 .cow_end = {
1312 .offset = cow_end_from,
1313 .nb_bytes = cow_end_to - cow_end_from,
1314 },
1315 };
1316
1317 qemu_co_queue_init(&(*m)->dependent_requests);
1318 QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
1319
1320 return 0;
1321}
1322
1323
1324
1325
1326
1327
1328static bool cluster_needs_new_alloc(BlockDriverState *bs, uint64_t l2_entry)
1329{
1330 switch (qcow2_get_cluster_type(bs, l2_entry)) {
1331 case QCOW2_CLUSTER_NORMAL:
1332 case QCOW2_CLUSTER_ZERO_ALLOC:
1333 if (l2_entry & QCOW_OFLAG_COPIED) {
1334 return false;
1335 }
1336
1337 case QCOW2_CLUSTER_UNALLOCATED:
1338 case QCOW2_CLUSTER_COMPRESSED:
1339 case QCOW2_CLUSTER_ZERO_PLAIN:
1340 return true;
1341 default:
1342 abort();
1343 }
1344}
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359static int count_single_write_clusters(BlockDriverState *bs, int nb_clusters,
1360 uint64_t *l2_slice, int l2_index,
1361 bool new_alloc)
1362{
1363 BDRVQcow2State *s = bs->opaque;
1364 uint64_t l2_entry = get_l2_entry(s, l2_slice, l2_index);
1365 uint64_t expected_offset = l2_entry & L2E_OFFSET_MASK;
1366 int i;
1367
1368 for (i = 0; i < nb_clusters; i++) {
1369 l2_entry = get_l2_entry(s, l2_slice, l2_index + i);
1370 if (cluster_needs_new_alloc(bs, l2_entry) != new_alloc) {
1371 break;
1372 }
1373 if (!new_alloc) {
1374 if (expected_offset != (l2_entry & L2E_OFFSET_MASK)) {
1375 break;
1376 }
1377 expected_offset += s->cluster_size;
1378 }
1379 }
1380
1381 assert(i <= nb_clusters);
1382 return i;
1383}
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
1400 uint64_t *cur_bytes, QCowL2Meta **m)
1401{
1402 BDRVQcow2State *s = bs->opaque;
1403 QCowL2Meta *old_alloc;
1404 uint64_t bytes = *cur_bytes;
1405
1406 QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
1407
1408 uint64_t start = guest_offset;
1409 uint64_t end = start + bytes;
1410 uint64_t old_start = start_of_cluster(s, l2meta_cow_start(old_alloc));
1411 uint64_t old_end = ROUND_UP(l2meta_cow_end(old_alloc), s->cluster_size);
1412
1413 if (end <= old_start || start >= old_end) {
1414
1415 continue;
1416 }
1417
1418 if (old_alloc->keep_old_clusters &&
1419 (end <= l2meta_cow_start(old_alloc) ||
1420 start >= l2meta_cow_end(old_alloc)))
1421 {
1422
1423
1424
1425
1426 continue;
1427 }
1428
1429
1430
1431 if (start < old_start) {
1432
1433 bytes = old_start - start;
1434 } else {
1435 bytes = 0;
1436 }
1437
1438
1439
1440
1441
1442
1443
1444 if (bytes == 0 && *m) {
1445 *cur_bytes = 0;
1446 return 0;
1447 }
1448
1449 if (bytes == 0) {
1450
1451
1452
1453
1454 qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock);
1455 return -EAGAIN;
1456 }
1457 }
1458
1459
1460
1461 *cur_bytes = bytes;
1462
1463 return 0;
1464}
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
1489 uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
1490{
1491 BDRVQcow2State *s = bs->opaque;
1492 int l2_index;
1493 uint64_t l2_entry, cluster_offset;
1494 uint64_t *l2_slice;
1495 uint64_t nb_clusters;
1496 unsigned int keep_clusters;
1497 int ret;
1498
1499 trace_qcow2_handle_copied(qemu_coroutine_self(), guest_offset, *host_offset,
1500 *bytes);
1501
1502 assert(*host_offset == INV_OFFSET || offset_into_cluster(s, guest_offset)
1503 == offset_into_cluster(s, *host_offset));
1504
1505
1506
1507
1508
1509 nb_clusters =
1510 size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
1511
1512 l2_index = offset_to_l2_slice_index(s, guest_offset);
1513 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1514
1515 nb_clusters = MIN(nb_clusters, BDRV_REQUEST_MAX_BYTES >> s->cluster_bits);
1516
1517
1518 ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
1519 if (ret < 0) {
1520 return ret;
1521 }
1522
1523 l2_entry = get_l2_entry(s, l2_slice, l2_index);
1524 cluster_offset = l2_entry & L2E_OFFSET_MASK;
1525
1526 if (!cluster_needs_new_alloc(bs, l2_entry)) {
1527 if (offset_into_cluster(s, cluster_offset)) {
1528 qcow2_signal_corruption(bs, true, -1, -1, "%s cluster offset "
1529 "%#" PRIx64 " unaligned (guest offset: %#"
1530 PRIx64 ")", l2_entry & QCOW_OFLAG_ZERO ?
1531 "Preallocated zero" : "Data",
1532 cluster_offset, guest_offset);
1533 ret = -EIO;
1534 goto out;
1535 }
1536
1537
1538 if (*host_offset != INV_OFFSET && cluster_offset != *host_offset) {
1539 *bytes = 0;
1540 ret = 0;
1541 goto out;
1542 }
1543
1544
1545 keep_clusters = count_single_write_clusters(bs, nb_clusters, l2_slice,
1546 l2_index, false);
1547 assert(keep_clusters <= nb_clusters);
1548
1549 *bytes = MIN(*bytes,
1550 keep_clusters * s->cluster_size
1551 - offset_into_cluster(s, guest_offset));
1552 assert(*bytes != 0);
1553
1554 ret = calculate_l2_meta(bs, cluster_offset, guest_offset,
1555 *bytes, l2_slice, m, true);
1556 if (ret < 0) {
1557 goto out;
1558 }
1559
1560 ret = 1;
1561 } else {
1562 ret = 0;
1563 }
1564
1565
1566out:
1567 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1568
1569
1570
1571 if (ret > 0) {
1572 *host_offset = cluster_offset + offset_into_cluster(s, guest_offset);
1573 }
1574
1575 return ret;
1576}
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
1598 uint64_t *host_offset, uint64_t *nb_clusters)
1599{
1600 BDRVQcow2State *s = bs->opaque;
1601
1602 trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
1603 *host_offset, *nb_clusters);
1604
1605 if (has_data_file(bs)) {
1606 assert(*host_offset == INV_OFFSET ||
1607 *host_offset == start_of_cluster(s, guest_offset));
1608 *host_offset = start_of_cluster(s, guest_offset);
1609 return 0;
1610 }
1611
1612
1613 trace_qcow2_cluster_alloc_phys(qemu_coroutine_self());
1614 if (*host_offset == INV_OFFSET) {
1615 int64_t cluster_offset =
1616 qcow2_alloc_clusters(bs, *nb_clusters * s->cluster_size);
1617 if (cluster_offset < 0) {
1618 return cluster_offset;
1619 }
1620 *host_offset = cluster_offset;
1621 return 0;
1622 } else {
1623 int64_t ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
1624 if (ret < 0) {
1625 return ret;
1626 }
1627 *nb_clusters = ret;
1628 return 0;
1629 }
1630}
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
1654 uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
1655{
1656 BDRVQcow2State *s = bs->opaque;
1657 int l2_index;
1658 uint64_t *l2_slice;
1659 uint64_t nb_clusters;
1660 int ret;
1661
1662 uint64_t alloc_cluster_offset;
1663
1664 trace_qcow2_handle_alloc(qemu_coroutine_self(), guest_offset, *host_offset,
1665 *bytes);
1666 assert(*bytes > 0);
1667
1668
1669
1670
1671
1672 nb_clusters =
1673 size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
1674
1675 l2_index = offset_to_l2_slice_index(s, guest_offset);
1676 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1677
1678 nb_clusters = MIN(nb_clusters, BDRV_REQUEST_MAX_BYTES >> s->cluster_bits);
1679
1680
1681 ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
1682 if (ret < 0) {
1683 return ret;
1684 }
1685
1686 nb_clusters = count_single_write_clusters(bs, nb_clusters,
1687 l2_slice, l2_index, true);
1688
1689
1690
1691
1692 assert(nb_clusters > 0);
1693
1694
1695 alloc_cluster_offset = *host_offset == INV_OFFSET ? INV_OFFSET :
1696 start_of_cluster(s, *host_offset);
1697 ret = do_alloc_cluster_offset(bs, guest_offset, &alloc_cluster_offset,
1698 &nb_clusters);
1699 if (ret < 0) {
1700 goto out;
1701 }
1702
1703
1704 if (nb_clusters == 0) {
1705 *bytes = 0;
1706 ret = 0;
1707 goto out;
1708 }
1709
1710 assert(alloc_cluster_offset != INV_OFFSET);
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726 uint64_t requested_bytes = *bytes + offset_into_cluster(s, guest_offset);
1727 int avail_bytes = nb_clusters << s->cluster_bits;
1728 int nb_bytes = MIN(requested_bytes, avail_bytes);
1729
1730 *host_offset = alloc_cluster_offset + offset_into_cluster(s, guest_offset);
1731 *bytes = MIN(*bytes, nb_bytes - offset_into_cluster(s, guest_offset));
1732 assert(*bytes != 0);
1733
1734 ret = calculate_l2_meta(bs, alloc_cluster_offset, guest_offset, *bytes,
1735 l2_slice, m, false);
1736 if (ret < 0) {
1737 goto out;
1738 }
1739
1740 ret = 1;
1741
1742out:
1743 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1744 return ret;
1745}
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774int qcow2_alloc_host_offset(BlockDriverState *bs, uint64_t offset,
1775 unsigned int *bytes, uint64_t *host_offset,
1776 QCowL2Meta **m)
1777{
1778 BDRVQcow2State *s = bs->opaque;
1779 uint64_t start, remaining;
1780 uint64_t cluster_offset;
1781 uint64_t cur_bytes;
1782 int ret;
1783
1784 trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *bytes);
1785
1786again:
1787 start = offset;
1788 remaining = *bytes;
1789 cluster_offset = INV_OFFSET;
1790 *host_offset = INV_OFFSET;
1791 cur_bytes = 0;
1792 *m = NULL;
1793
1794 while (true) {
1795
1796 if (*host_offset == INV_OFFSET && cluster_offset != INV_OFFSET) {
1797 *host_offset = cluster_offset;
1798 }
1799
1800 assert(remaining >= cur_bytes);
1801
1802 start += cur_bytes;
1803 remaining -= cur_bytes;
1804
1805 if (cluster_offset != INV_OFFSET) {
1806 cluster_offset += cur_bytes;
1807 }
1808
1809 if (remaining == 0) {
1810 break;
1811 }
1812
1813 cur_bytes = remaining;
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833 ret = handle_dependencies(bs, start, &cur_bytes, m);
1834 if (ret == -EAGAIN) {
1835
1836
1837
1838 assert(*m == NULL);
1839 goto again;
1840 } else if (ret < 0) {
1841 return ret;
1842 } else if (cur_bytes == 0) {
1843 break;
1844 } else {
1845
1846
1847
1848 }
1849
1850
1851
1852
1853 ret = handle_copied(bs, start, &cluster_offset, &cur_bytes, m);
1854 if (ret < 0) {
1855 return ret;
1856 } else if (ret) {
1857 continue;
1858 } else if (cur_bytes == 0) {
1859 break;
1860 }
1861
1862
1863
1864
1865
1866 ret = handle_alloc(bs, start, &cluster_offset, &cur_bytes, m);
1867 if (ret < 0) {
1868 return ret;
1869 } else if (ret) {
1870 continue;
1871 } else {
1872 assert(cur_bytes == 0);
1873 break;
1874 }
1875 }
1876
1877 *bytes -= remaining;
1878 assert(*bytes > 0);
1879 assert(*host_offset != INV_OFFSET);
1880 assert(offset_into_cluster(s, *host_offset) ==
1881 offset_into_cluster(s, offset));
1882
1883 return 0;
1884}
1885
1886
1887
1888
1889
1890
1891static int discard_in_l2_slice(BlockDriverState *bs, uint64_t offset,
1892 uint64_t nb_clusters,
1893 enum qcow2_discard_type type, bool full_discard)
1894{
1895 BDRVQcow2State *s = bs->opaque;
1896 uint64_t *l2_slice;
1897 int l2_index;
1898 int ret;
1899 int i;
1900
1901 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
1902 if (ret < 0) {
1903 return ret;
1904 }
1905
1906
1907 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
1908 assert(nb_clusters <= INT_MAX);
1909
1910 for (i = 0; i < nb_clusters; i++) {
1911 uint64_t old_l2_entry = get_l2_entry(s, l2_slice, l2_index + i);
1912 uint64_t old_l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i);
1913 uint64_t new_l2_entry = old_l2_entry;
1914 uint64_t new_l2_bitmap = old_l2_bitmap;
1915 QCow2ClusterType cluster_type =
1916 qcow2_get_cluster_type(bs, old_l2_entry);
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931 if (full_discard) {
1932 new_l2_entry = new_l2_bitmap = 0;
1933 } else if (bs->backing || qcow2_cluster_is_allocated(cluster_type)) {
1934 if (has_subclusters(s)) {
1935 new_l2_entry = 0;
1936 new_l2_bitmap = QCOW_L2_BITMAP_ALL_ZEROES;
1937 } else {
1938 new_l2_entry = s->qcow_version >= 3 ? QCOW_OFLAG_ZERO : 0;
1939 }
1940 }
1941
1942 if (old_l2_entry == new_l2_entry && old_l2_bitmap == new_l2_bitmap) {
1943 continue;
1944 }
1945
1946
1947 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
1948 set_l2_entry(s, l2_slice, l2_index + i, new_l2_entry);
1949 if (has_subclusters(s)) {
1950 set_l2_bitmap(s, l2_slice, l2_index + i, new_l2_bitmap);
1951 }
1952
1953 qcow2_free_any_cluster(bs, old_l2_entry, type);
1954 }
1955
1956 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
1957
1958 return nb_clusters;
1959}
1960
1961int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
1962 uint64_t bytes, enum qcow2_discard_type type,
1963 bool full_discard)
1964{
1965 BDRVQcow2State *s = bs->opaque;
1966 uint64_t end_offset = offset + bytes;
1967 uint64_t nb_clusters;
1968 int64_t cleared;
1969 int ret;
1970
1971
1972 assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
1973 assert(QEMU_IS_ALIGNED(end_offset, s->cluster_size) ||
1974 end_offset == bs->total_sectors << BDRV_SECTOR_BITS);
1975
1976 nb_clusters = size_to_clusters(s, bytes);
1977
1978 s->cache_discards = true;
1979
1980
1981 while (nb_clusters > 0) {
1982 cleared = discard_in_l2_slice(bs, offset, nb_clusters, type,
1983 full_discard);
1984 if (cleared < 0) {
1985 ret = cleared;
1986 goto fail;
1987 }
1988
1989 nb_clusters -= cleared;
1990 offset += (cleared * s->cluster_size);
1991 }
1992
1993 ret = 0;
1994fail:
1995 s->cache_discards = false;
1996 qcow2_process_discards(bs, ret);
1997
1998 return ret;
1999}
2000
2001
2002
2003
2004
2005
2006static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset,
2007 uint64_t nb_clusters, int flags)
2008{
2009 BDRVQcow2State *s = bs->opaque;
2010 uint64_t *l2_slice;
2011 int l2_index;
2012 int ret;
2013 int i;
2014
2015 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
2016 if (ret < 0) {
2017 return ret;
2018 }
2019
2020
2021 nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
2022 assert(nb_clusters <= INT_MAX);
2023
2024 for (i = 0; i < nb_clusters; i++) {
2025 uint64_t old_l2_entry = get_l2_entry(s, l2_slice, l2_index + i);
2026 uint64_t old_l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i);
2027 QCow2ClusterType type = qcow2_get_cluster_type(bs, old_l2_entry);
2028 bool unmap = (type == QCOW2_CLUSTER_COMPRESSED) ||
2029 ((flags & BDRV_REQ_MAY_UNMAP) && qcow2_cluster_is_allocated(type));
2030 uint64_t new_l2_entry = unmap ? 0 : old_l2_entry;
2031 uint64_t new_l2_bitmap = old_l2_bitmap;
2032
2033 if (has_subclusters(s)) {
2034 new_l2_bitmap = QCOW_L2_BITMAP_ALL_ZEROES;
2035 } else {
2036 new_l2_entry |= QCOW_OFLAG_ZERO;
2037 }
2038
2039 if (old_l2_entry == new_l2_entry && old_l2_bitmap == new_l2_bitmap) {
2040 continue;
2041 }
2042
2043
2044 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
2045 set_l2_entry(s, l2_slice, l2_index + i, new_l2_entry);
2046 if (has_subclusters(s)) {
2047 set_l2_bitmap(s, l2_slice, l2_index + i, new_l2_bitmap);
2048 }
2049
2050
2051 if (unmap) {
2052 qcow2_free_any_cluster(bs, old_l2_entry, QCOW2_DISCARD_REQUEST);
2053 }
2054 }
2055
2056 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2057
2058 return nb_clusters;
2059}
2060
2061static int zero_l2_subclusters(BlockDriverState *bs, uint64_t offset,
2062 unsigned nb_subclusters)
2063{
2064 BDRVQcow2State *s = bs->opaque;
2065 uint64_t *l2_slice;
2066 uint64_t old_l2_bitmap, l2_bitmap;
2067 int l2_index, ret, sc = offset_to_sc_index(s, offset);
2068
2069
2070 assert(nb_subclusters > 0 && nb_subclusters < s->subclusters_per_cluster);
2071 assert(sc + nb_subclusters <= s->subclusters_per_cluster);
2072 assert(offset_into_subcluster(s, offset) == 0);
2073
2074 ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
2075 if (ret < 0) {
2076 return ret;
2077 }
2078
2079 switch (qcow2_get_cluster_type(bs, get_l2_entry(s, l2_slice, l2_index))) {
2080 case QCOW2_CLUSTER_COMPRESSED:
2081 ret = -ENOTSUP;
2082 goto out;
2083 case QCOW2_CLUSTER_NORMAL:
2084 case QCOW2_CLUSTER_UNALLOCATED:
2085 break;
2086 default:
2087 g_assert_not_reached();
2088 }
2089
2090 old_l2_bitmap = l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index);
2091
2092 l2_bitmap |= QCOW_OFLAG_SUB_ZERO_RANGE(sc, sc + nb_subclusters);
2093 l2_bitmap &= ~QCOW_OFLAG_SUB_ALLOC_RANGE(sc, sc + nb_subclusters);
2094
2095 if (old_l2_bitmap != l2_bitmap) {
2096 set_l2_bitmap(s, l2_slice, l2_index, l2_bitmap);
2097 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
2098 }
2099
2100 ret = 0;
2101out:
2102 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2103
2104 return ret;
2105}
2106
2107int qcow2_subcluster_zeroize(BlockDriverState *bs, uint64_t offset,
2108 uint64_t bytes, int flags)
2109{
2110 BDRVQcow2State *s = bs->opaque;
2111 uint64_t end_offset = offset + bytes;
2112 uint64_t nb_clusters;
2113 unsigned head, tail;
2114 int64_t cleared;
2115 int ret;
2116
2117
2118
2119 if (data_file_is_raw(bs)) {
2120 assert(has_data_file(bs));
2121 ret = bdrv_co_pwrite_zeroes(s->data_file, offset, bytes, flags);
2122 if (ret < 0) {
2123 return ret;
2124 }
2125 }
2126
2127
2128 assert(offset_into_subcluster(s, offset) == 0);
2129 assert(offset_into_subcluster(s, end_offset) == 0 ||
2130 end_offset >= bs->total_sectors << BDRV_SECTOR_BITS);
2131
2132
2133
2134
2135
2136 if (s->qcow_version < 3) {
2137 if (!bs->backing) {
2138 return qcow2_cluster_discard(bs, offset, bytes,
2139 QCOW2_DISCARD_REQUEST, false);
2140 }
2141 return -ENOTSUP;
2142 }
2143
2144 head = MIN(end_offset, ROUND_UP(offset, s->cluster_size)) - offset;
2145 offset += head;
2146
2147 tail = (end_offset >= bs->total_sectors << BDRV_SECTOR_BITS) ? 0 :
2148 end_offset - MAX(offset, start_of_cluster(s, end_offset));
2149 end_offset -= tail;
2150
2151 s->cache_discards = true;
2152
2153 if (head) {
2154 ret = zero_l2_subclusters(bs, offset - head,
2155 size_to_subclusters(s, head));
2156 if (ret < 0) {
2157 goto fail;
2158 }
2159 }
2160
2161
2162 nb_clusters = size_to_clusters(s, end_offset - offset);
2163
2164 while (nb_clusters > 0) {
2165 cleared = zero_in_l2_slice(bs, offset, nb_clusters, flags);
2166 if (cleared < 0) {
2167 ret = cleared;
2168 goto fail;
2169 }
2170
2171 nb_clusters -= cleared;
2172 offset += (cleared * s->cluster_size);
2173 }
2174
2175 if (tail) {
2176 ret = zero_l2_subclusters(bs, end_offset, size_to_subclusters(s, tail));
2177 if (ret < 0) {
2178 goto fail;
2179 }
2180 }
2181
2182 ret = 0;
2183fail:
2184 s->cache_discards = false;
2185 qcow2_process_discards(bs, ret);
2186
2187 return ret;
2188}
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
2199 int l1_size, int64_t *visited_l1_entries,
2200 int64_t l1_entries,
2201 BlockDriverAmendStatusCB *status_cb,
2202 void *cb_opaque)
2203{
2204 BDRVQcow2State *s = bs->opaque;
2205 bool is_active_l1 = (l1_table == s->l1_table);
2206 uint64_t *l2_slice = NULL;
2207 unsigned slice, slice_size2, n_slices;
2208 int ret;
2209 int i, j;
2210
2211
2212 assert(!has_subclusters(s));
2213
2214 slice_size2 = s->l2_slice_size * l2_entry_size(s);
2215 n_slices = s->cluster_size / slice_size2;
2216
2217 if (!is_active_l1) {
2218
2219
2220 l2_slice = qemu_try_blockalign(bs->file->bs, slice_size2);
2221 if (l2_slice == NULL) {
2222 return -ENOMEM;
2223 }
2224 }
2225
2226 for (i = 0; i < l1_size; i++) {
2227 uint64_t l2_offset = l1_table[i] & L1E_OFFSET_MASK;
2228 uint64_t l2_refcount;
2229
2230 if (!l2_offset) {
2231
2232 (*visited_l1_entries)++;
2233 if (status_cb) {
2234 status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque);
2235 }
2236 continue;
2237 }
2238
2239 if (offset_into_cluster(s, l2_offset)) {
2240 qcow2_signal_corruption(bs, true, -1, -1, "L2 table offset %#"
2241 PRIx64 " unaligned (L1 index: %#x)",
2242 l2_offset, i);
2243 ret = -EIO;
2244 goto fail;
2245 }
2246
2247 ret = qcow2_get_refcount(bs, l2_offset >> s->cluster_bits,
2248 &l2_refcount);
2249 if (ret < 0) {
2250 goto fail;
2251 }
2252
2253 for (slice = 0; slice < n_slices; slice++) {
2254 uint64_t slice_offset = l2_offset + slice * slice_size2;
2255 bool l2_dirty = false;
2256 if (is_active_l1) {
2257
2258 ret = qcow2_cache_get(bs, s->l2_table_cache, slice_offset,
2259 (void **)&l2_slice);
2260 } else {
2261
2262 ret = bdrv_pread(bs->file, slice_offset, l2_slice, slice_size2);
2263 }
2264 if (ret < 0) {
2265 goto fail;
2266 }
2267
2268 for (j = 0; j < s->l2_slice_size; j++) {
2269 uint64_t l2_entry = get_l2_entry(s, l2_slice, j);
2270 int64_t offset = l2_entry & L2E_OFFSET_MASK;
2271 QCow2ClusterType cluster_type =
2272 qcow2_get_cluster_type(bs, l2_entry);
2273
2274 if (cluster_type != QCOW2_CLUSTER_ZERO_PLAIN &&
2275 cluster_type != QCOW2_CLUSTER_ZERO_ALLOC) {
2276 continue;
2277 }
2278
2279 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
2280 if (!bs->backing) {
2281
2282
2283
2284
2285
2286 set_l2_entry(s, l2_slice, j, 0);
2287 l2_dirty = true;
2288 continue;
2289 }
2290
2291 offset = qcow2_alloc_clusters(bs, s->cluster_size);
2292 if (offset < 0) {
2293 ret = offset;
2294 goto fail;
2295 }
2296
2297
2298 assert((offset & L2E_OFFSET_MASK) == offset);
2299
2300 if (l2_refcount > 1) {
2301
2302
2303 ret = qcow2_update_cluster_refcount(
2304 bs, offset >> s->cluster_bits,
2305 refcount_diff(1, l2_refcount), false,
2306 QCOW2_DISCARD_OTHER);
2307 if (ret < 0) {
2308 qcow2_free_clusters(bs, offset, s->cluster_size,
2309 QCOW2_DISCARD_OTHER);
2310 goto fail;
2311 }
2312 }
2313 }
2314
2315 if (offset_into_cluster(s, offset)) {
2316 int l2_index = slice * s->l2_slice_size + j;
2317 qcow2_signal_corruption(
2318 bs, true, -1, -1,
2319 "Cluster allocation offset "
2320 "%#" PRIx64 " unaligned (L2 offset: %#"
2321 PRIx64 ", L2 index: %#x)", offset,
2322 l2_offset, l2_index);
2323 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
2324 qcow2_free_clusters(bs, offset, s->cluster_size,
2325 QCOW2_DISCARD_ALWAYS);
2326 }
2327 ret = -EIO;
2328 goto fail;
2329 }
2330
2331 ret = qcow2_pre_write_overlap_check(bs, 0, offset,
2332 s->cluster_size, true);
2333 if (ret < 0) {
2334 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
2335 qcow2_free_clusters(bs, offset, s->cluster_size,
2336 QCOW2_DISCARD_ALWAYS);
2337 }
2338 goto fail;
2339 }
2340
2341 ret = bdrv_pwrite_zeroes(s->data_file, offset,
2342 s->cluster_size, 0);
2343 if (ret < 0) {
2344 if (cluster_type == QCOW2_CLUSTER_ZERO_PLAIN) {
2345 qcow2_free_clusters(bs, offset, s->cluster_size,
2346 QCOW2_DISCARD_ALWAYS);
2347 }
2348 goto fail;
2349 }
2350
2351 if (l2_refcount == 1) {
2352 set_l2_entry(s, l2_slice, j, offset | QCOW_OFLAG_COPIED);
2353 } else {
2354 set_l2_entry(s, l2_slice, j, offset);
2355 }
2356
2357
2358
2359
2360 l2_dirty = true;
2361 }
2362
2363 if (is_active_l1) {
2364 if (l2_dirty) {
2365 qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
2366 qcow2_cache_depends_on_flush(s->l2_table_cache);
2367 }
2368 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2369 } else {
2370 if (l2_dirty) {
2371 ret = qcow2_pre_write_overlap_check(
2372 bs, QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2,
2373 slice_offset, slice_size2, false);
2374 if (ret < 0) {
2375 goto fail;
2376 }
2377
2378 ret = bdrv_pwrite(bs->file, slice_offset,
2379 l2_slice, slice_size2);
2380 if (ret < 0) {
2381 goto fail;
2382 }
2383 }
2384 }
2385 }
2386
2387 (*visited_l1_entries)++;
2388 if (status_cb) {
2389 status_cb(bs, *visited_l1_entries, l1_entries, cb_opaque);
2390 }
2391 }
2392
2393 ret = 0;
2394
2395fail:
2396 if (l2_slice) {
2397 if (!is_active_l1) {
2398 qemu_vfree(l2_slice);
2399 } else {
2400 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
2401 }
2402 }
2403 return ret;
2404}
2405
2406
2407
2408
2409
2410
2411
2412int qcow2_expand_zero_clusters(BlockDriverState *bs,
2413 BlockDriverAmendStatusCB *status_cb,
2414 void *cb_opaque)
2415{
2416 BDRVQcow2State *s = bs->opaque;
2417 uint64_t *l1_table = NULL;
2418 int64_t l1_entries = 0, visited_l1_entries = 0;
2419 int ret;
2420 int i, j;
2421
2422 if (status_cb) {
2423 l1_entries = s->l1_size;
2424 for (i = 0; i < s->nb_snapshots; i++) {
2425 l1_entries += s->snapshots[i].l1_size;
2426 }
2427 }
2428
2429 ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size,
2430 &visited_l1_entries, l1_entries,
2431 status_cb, cb_opaque);
2432 if (ret < 0) {
2433 goto fail;
2434 }
2435
2436
2437
2438
2439
2440
2441
2442
2443 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2444 if (ret < 0) {
2445 goto fail;
2446 }
2447
2448 for (i = 0; i < s->nb_snapshots; i++) {
2449 int l1_size2;
2450 uint64_t *new_l1_table;
2451 Error *local_err = NULL;
2452
2453 ret = qcow2_validate_table(bs, s->snapshots[i].l1_table_offset,
2454 s->snapshots[i].l1_size, L1E_SIZE,
2455 QCOW_MAX_L1_SIZE, "Snapshot L1 table",
2456 &local_err);
2457 if (ret < 0) {
2458 error_report_err(local_err);
2459 goto fail;
2460 }
2461
2462 l1_size2 = s->snapshots[i].l1_size * L1E_SIZE;
2463 new_l1_table = g_try_realloc(l1_table, l1_size2);
2464
2465 if (!new_l1_table) {
2466 ret = -ENOMEM;
2467 goto fail;
2468 }
2469
2470 l1_table = new_l1_table;
2471
2472 ret = bdrv_pread(bs->file, s->snapshots[i].l1_table_offset,
2473 l1_table, l1_size2);
2474 if (ret < 0) {
2475 goto fail;
2476 }
2477
2478 for (j = 0; j < s->snapshots[i].l1_size; j++) {
2479 be64_to_cpus(&l1_table[j]);
2480 }
2481
2482 ret = expand_zero_clusters_in_l1(bs, l1_table, s->snapshots[i].l1_size,
2483 &visited_l1_entries, l1_entries,
2484 status_cb, cb_opaque);
2485 if (ret < 0) {
2486 goto fail;
2487 }
2488 }
2489
2490 ret = 0;
2491
2492fail:
2493 g_free(l1_table);
2494 return ret;
2495}
2496
2497void qcow2_parse_compressed_l2_entry(BlockDriverState *bs, uint64_t l2_entry,
2498 uint64_t *coffset, int *csize)
2499{
2500 BDRVQcow2State *s = bs->opaque;
2501 int nb_csectors;
2502
2503 assert(qcow2_get_cluster_type(bs, l2_entry) == QCOW2_CLUSTER_COMPRESSED);
2504
2505 *coffset = l2_entry & s->cluster_offset_mask;
2506
2507 nb_csectors = ((l2_entry >> s->csize_shift) & s->csize_mask) + 1;
2508 *csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE -
2509 (*coffset & (QCOW2_COMPRESSED_SECTOR_SIZE - 1));
2510}
2511