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io: use bind() to check for IPv4/6 availability
[qemu.git] / block / qcow2.c
blob8babecdab242b8421cad8b649734784ce22e7732
1 /*
2 * Block driver for the QCOW version 2 format
3 *
4 * Copyright (c) 2004-2006 Fabrice Bellard
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24 #include "qemu/osdep.h"
25 #include "qemu-common.h"
26 #include "block/block_int.h"
27 #include "qemu/module.h"
28 #include <zlib.h>
29 #include "block/qcow2.h"
30 #include "qemu/error-report.h"
31 #include "qapi/qmp/qerror.h"
32 #include "qapi/qmp/qbool.h"
33 #include "qapi/util.h"
34 #include "qapi/qmp/types.h"
35 #include "qapi-event.h"
36 #include "trace.h"
37 #include "qemu/option_int.h"
38
39 /*
40 Differences with QCOW:
41
42 - Support for multiple incremental snapshots.
43 - Memory management by reference counts.
44 - Clusters which have a reference count of one have the bit
45 QCOW_OFLAG_COPIED to optimize write performance.
46 - Size of compressed clusters is stored in sectors to reduce bit usage
47 in the cluster offsets.
48 - Support for storing additional data (such as the VM state) in the
49 snapshots.
50 - If a backing store is used, the cluster size is not constrained
51 (could be backported to QCOW).
52 - L2 tables have always a size of one cluster.
53 */
54
55
56 typedef struct {
57 uint32_t magic;
58 uint32_t len;
59 } QEMU_PACKED QCowExtension;
60
61 #define QCOW2_EXT_MAGIC_END 0
62 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
63 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
64
65 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
66 {
67 const QCowHeader *cow_header = (const void *)buf;
68
69 if (buf_size >= sizeof(QCowHeader) &&
70 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
71 be32_to_cpu(cow_header->version) >= 2)
72 return 100;
73 else
74 return 0;
75 }
76
77
78 /*
79 * read qcow2 extension and fill bs
80 * start reading from start_offset
81 * finish reading upon magic of value 0 or when end_offset reached
82 * unknown magic is skipped (future extension this version knows nothing about)
83 * return 0 upon success, non-0 otherwise
84 */
85 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
86 uint64_t end_offset, void **p_feature_table,
87 Error **errp)
88 {
89 BDRVQcow2State *s = bs->opaque;
90 QCowExtension ext;
91 uint64_t offset;
92 int ret;
93
94 #ifdef DEBUG_EXT
95 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
96 #endif
97 offset = start_offset;
98 while (offset < end_offset) {
99
100 #ifdef DEBUG_EXT
101 /* Sanity check */
102 if (offset > s->cluster_size)
103 printf("qcow2_read_extension: suspicious offset %lu\n", offset);
104
105 printf("attempting to read extended header in offset %lu\n", offset);
106 #endif
107
108 ret = bdrv_pread(bs->file->bs, offset, &ext, sizeof(ext));
109 if (ret < 0) {
110 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: "
111 "pread fail from offset %" PRIu64, offset);
112 return 1;
113 }
114 be32_to_cpus(&ext.magic);
115 be32_to_cpus(&ext.len);
116 offset += sizeof(ext);
117 #ifdef DEBUG_EXT
118 printf("ext.magic = 0x%x\n", ext.magic);
119 #endif
120 if (offset > end_offset || ext.len > end_offset - offset) {
121 error_setg(errp, "Header extension too large");
122 return -EINVAL;
123 }
124
125 switch (ext.magic) {
126 case QCOW2_EXT_MAGIC_END:
127 return 0;
128
129 case QCOW2_EXT_MAGIC_BACKING_FORMAT:
130 if (ext.len >= sizeof(bs->backing_format)) {
131 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32
132 " too large (>=%zu)", ext.len,
133 sizeof(bs->backing_format));
134 return 2;
135 }
136 ret = bdrv_pread(bs->file->bs, offset, bs->backing_format, ext.len);
137 if (ret < 0) {
138 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: "
139 "Could not read format name");
140 return 3;
141 }
142 bs->backing_format[ext.len] = '\0';
143 s->image_backing_format = g_strdup(bs->backing_format);
144 #ifdef DEBUG_EXT
145 printf("Qcow2: Got format extension %s\n", bs->backing_format);
146 #endif
147 break;
148
149 case QCOW2_EXT_MAGIC_FEATURE_TABLE:
150 if (p_feature_table != NULL) {
151 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature));
152 ret = bdrv_pread(bs->file->bs, offset , feature_table, ext.len);
153 if (ret < 0) {
154 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
155 "Could not read table");
156 return ret;
157 }
158
159 *p_feature_table = feature_table;
160 }
161 break;
162
163 default:
164 /* unknown magic - save it in case we need to rewrite the header */
165 {
166 Qcow2UnknownHeaderExtension *uext;
167
168 uext = g_malloc0(sizeof(*uext) + ext.len);
169 uext->magic = ext.magic;
170 uext->len = ext.len;
171 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next);
172
173 ret = bdrv_pread(bs->file->bs, offset , uext->data, uext->len);
174 if (ret < 0) {
175 error_setg_errno(errp, -ret, "ERROR: unknown extension: "
176 "Could not read data");
177 return ret;
178 }
179 }
180 break;
181 }
182
183 offset += ((ext.len + 7) & ~7);
184 }
185
186 return 0;
187 }
188
189 static void cleanup_unknown_header_ext(BlockDriverState *bs)
190 {
191 BDRVQcow2State *s = bs->opaque;
192 Qcow2UnknownHeaderExtension *uext, *next;
193
194 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) {
195 QLIST_REMOVE(uext, next);
196 g_free(uext);
197 }
198 }
199
200 static void GCC_FMT_ATTR(3, 4) report_unsupported(BlockDriverState *bs,
201 Error **errp, const char *fmt, ...)
202 {
203 char msg[64];
204 va_list ap;
205
206 va_start(ap, fmt);
207 vsnprintf(msg, sizeof(msg), fmt, ap);
208 va_end(ap);
209
210 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
211 bdrv_get_device_or_node_name(bs), "qcow2", msg);
212 }
213
214 static void report_unsupported_feature(BlockDriverState *bs,
215 Error **errp, Qcow2Feature *table, uint64_t mask)
216 {
217 char *features = g_strdup("");
218 char *old;
219
220 while (table && table->name[0] != '\0') {
221 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
222 if (mask & (1ULL << table->bit)) {
223 old = features;
224 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
225 table->name);
226 g_free(old);
227 mask &= ~(1ULL << table->bit);
228 }
229 }
230 table++;
231 }
232
233 if (mask) {
234 old = features;
235 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
236 old, *old ? ", " : "", mask);
237 g_free(old);
238 }
239
240 report_unsupported(bs, errp, "%s", features);
241 g_free(features);
242 }
243
244 /*
245 * Sets the dirty bit and flushes afterwards if necessary.
246 *
247 * The incompatible_features bit is only set if the image file header was
248 * updated successfully. Therefore it is not required to check the return
249 * value of this function.
250 */
251 int qcow2_mark_dirty(BlockDriverState *bs)
252 {
253 BDRVQcow2State *s = bs->opaque;
254 uint64_t val;
255 int ret;
256
257 assert(s->qcow_version >= 3);
258
259 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
260 return 0; /* already dirty */
261 }
262
263 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY);
264 ret = bdrv_pwrite(bs->file->bs, offsetof(QCowHeader, incompatible_features),
265 &val, sizeof(val));
266 if (ret < 0) {
267 return ret;
268 }
269 ret = bdrv_flush(bs->file->bs);
270 if (ret < 0) {
271 return ret;
272 }
273
274 /* Only treat image as dirty if the header was updated successfully */
275 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY;
276 return 0;
277 }
278
279 /*
280 * Clears the dirty bit and flushes before if necessary. Only call this
281 * function when there are no pending requests, it does not guard against
282 * concurrent requests dirtying the image.
283 */
284 static int qcow2_mark_clean(BlockDriverState *bs)
285 {
286 BDRVQcow2State *s = bs->opaque;
287
288 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
289 int ret;
290
291 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY;
292
293 ret = bdrv_flush(bs);
294 if (ret < 0) {
295 return ret;
296 }
297
298 return qcow2_update_header(bs);
299 }
300 return 0;
301 }
302
303 /*
304 * Marks the image as corrupt.
305 */
306 int qcow2_mark_corrupt(BlockDriverState *bs)
307 {
308 BDRVQcow2State *s = bs->opaque;
309
310 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
311 return qcow2_update_header(bs);
312 }
313
314 /*
315 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
316 * before if necessary.
317 */
318 int qcow2_mark_consistent(BlockDriverState *bs)
319 {
320 BDRVQcow2State *s = bs->opaque;
321
322 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
323 int ret = bdrv_flush(bs);
324 if (ret < 0) {
325 return ret;
326 }
327
328 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
329 return qcow2_update_header(bs);
330 }
331 return 0;
332 }
333
334 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result,
335 BdrvCheckMode fix)
336 {
337 int ret = qcow2_check_refcounts(bs, result, fix);
338 if (ret < 0) {
339 return ret;
340 }
341
342 if (fix && result->check_errors == 0 && result->corruptions == 0) {
343 ret = qcow2_mark_clean(bs);
344 if (ret < 0) {
345 return ret;
346 }
347 return qcow2_mark_consistent(bs);
348 }
349 return ret;
350 }
351
352 static int validate_table_offset(BlockDriverState *bs, uint64_t offset,
353 uint64_t entries, size_t entry_len)
354 {
355 BDRVQcow2State *s = bs->opaque;
356 uint64_t size;
357
358 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
359 * because values will be passed to qemu functions taking int64_t. */
360 if (entries > INT64_MAX / entry_len) {
361 return -EINVAL;
362 }
363
364 size = entries * entry_len;
365
366 if (INT64_MAX - size < offset) {
367 return -EINVAL;
368 }
369
370 /* Tables must be cluster aligned */
371 if (offset & (s->cluster_size - 1)) {
372 return -EINVAL;
373 }
374
375 return 0;
376 }
377
378 static QemuOptsList qcow2_runtime_opts = {
379 .name = "qcow2",
380 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
381 .desc = {
382 {
383 .name = QCOW2_OPT_LAZY_REFCOUNTS,
384 .type = QEMU_OPT_BOOL,
385 .help = "Postpone refcount updates",
386 },
387 {
388 .name = QCOW2_OPT_DISCARD_REQUEST,
389 .type = QEMU_OPT_BOOL,
390 .help = "Pass guest discard requests to the layer below",
391 },
392 {
393 .name = QCOW2_OPT_DISCARD_SNAPSHOT,
394 .type = QEMU_OPT_BOOL,
395 .help = "Generate discard requests when snapshot related space "
396 "is freed",
397 },
398 {
399 .name = QCOW2_OPT_DISCARD_OTHER,
400 .type = QEMU_OPT_BOOL,
401 .help = "Generate discard requests when other clusters are freed",
402 },
403 {
404 .name = QCOW2_OPT_OVERLAP,
405 .type = QEMU_OPT_STRING,
406 .help = "Selects which overlap checks to perform from a range of "
407 "templates (none, constant, cached, all)",
408 },
409 {
410 .name = QCOW2_OPT_OVERLAP_TEMPLATE,
411 .type = QEMU_OPT_STRING,
412 .help = "Selects which overlap checks to perform from a range of "
413 "templates (none, constant, cached, all)",
414 },
415 {
416 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER,
417 .type = QEMU_OPT_BOOL,
418 .help = "Check for unintended writes into the main qcow2 header",
419 },
420 {
421 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1,
422 .type = QEMU_OPT_BOOL,
423 .help = "Check for unintended writes into the active L1 table",
424 },
425 {
426 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2,
427 .type = QEMU_OPT_BOOL,
428 .help = "Check for unintended writes into an active L2 table",
429 },
430 {
431 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
432 .type = QEMU_OPT_BOOL,
433 .help = "Check for unintended writes into the refcount table",
434 },
435 {
436 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
437 .type = QEMU_OPT_BOOL,
438 .help = "Check for unintended writes into a refcount block",
439 },
440 {
441 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
442 .type = QEMU_OPT_BOOL,
443 .help = "Check for unintended writes into the snapshot table",
444 },
445 {
446 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1,
447 .type = QEMU_OPT_BOOL,
448 .help = "Check for unintended writes into an inactive L1 table",
449 },
450 {
451 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2,
452 .type = QEMU_OPT_BOOL,
453 .help = "Check for unintended writes into an inactive L2 table",
454 },
455 {
456 .name = QCOW2_OPT_CACHE_SIZE,
457 .type = QEMU_OPT_SIZE,
458 .help = "Maximum combined metadata (L2 tables and refcount blocks) "
459 "cache size",
460 },
461 {
462 .name = QCOW2_OPT_L2_CACHE_SIZE,
463 .type = QEMU_OPT_SIZE,
464 .help = "Maximum L2 table cache size",
465 },
466 {
467 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE,
468 .type = QEMU_OPT_SIZE,
469 .help = "Maximum refcount block cache size",
470 },
471 {
472 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL,
473 .type = QEMU_OPT_NUMBER,
474 .help = "Clean unused cache entries after this time (in seconds)",
475 },
476 { /* end of list */ }
477 },
478 };
479
480 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = {
481 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER,
482 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1,
483 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2,
484 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
485 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
486 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
487 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1,
488 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2,
489 };
490
491 static void cache_clean_timer_cb(void *opaque)
492 {
493 BlockDriverState *bs = opaque;
494 BDRVQcow2State *s = bs->opaque;
495 qcow2_cache_clean_unused(bs, s->l2_table_cache);
496 qcow2_cache_clean_unused(bs, s->refcount_block_cache);
497 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
498 (int64_t) s->cache_clean_interval * 1000);
499 }
500
501 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context)
502 {
503 BDRVQcow2State *s = bs->opaque;
504 if (s->cache_clean_interval > 0) {
505 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL,
506 SCALE_MS, cache_clean_timer_cb,
507 bs);
508 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
509 (int64_t) s->cache_clean_interval * 1000);
510 }
511 }
512
513 static void cache_clean_timer_del(BlockDriverState *bs)
514 {
515 BDRVQcow2State *s = bs->opaque;
516 if (s->cache_clean_timer) {
517 timer_del(s->cache_clean_timer);
518 timer_free(s->cache_clean_timer);
519 s->cache_clean_timer = NULL;
520 }
521 }
522
523 static void qcow2_detach_aio_context(BlockDriverState *bs)
524 {
525 cache_clean_timer_del(bs);
526 }
527
528 static void qcow2_attach_aio_context(BlockDriverState *bs,
529 AioContext *new_context)
530 {
531 cache_clean_timer_init(bs, new_context);
532 }
533
534 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
535 uint64_t *l2_cache_size,
536 uint64_t *refcount_cache_size, Error **errp)
537 {
538 BDRVQcow2State *s = bs->opaque;
539 uint64_t combined_cache_size;
540 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
541
542 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
543 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
544 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
545
546 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
547 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0);
548 *refcount_cache_size = qemu_opt_get_size(opts,
549 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
550
551 if (combined_cache_size_set) {
552 if (l2_cache_size_set && refcount_cache_size_set) {
553 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
554 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
555 "the same time");
556 return;
557 } else if (*l2_cache_size > combined_cache_size) {
558 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
559 QCOW2_OPT_CACHE_SIZE);
560 return;
561 } else if (*refcount_cache_size > combined_cache_size) {
562 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed "
563 QCOW2_OPT_CACHE_SIZE);
564 return;
565 }
566
567 if (l2_cache_size_set) {
568 *refcount_cache_size = combined_cache_size - *l2_cache_size;
569 } else if (refcount_cache_size_set) {
570 *l2_cache_size = combined_cache_size - *refcount_cache_size;
571 } else {
572 *refcount_cache_size = combined_cache_size
573 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1);
574 *l2_cache_size = combined_cache_size - *refcount_cache_size;
575 }
576 } else {
577 if (!l2_cache_size_set && !refcount_cache_size_set) {
578 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE,
579 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
580 * s->cluster_size);
581 *refcount_cache_size = *l2_cache_size
582 / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
583 } else if (!l2_cache_size_set) {
584 *l2_cache_size = *refcount_cache_size
585 * DEFAULT_L2_REFCOUNT_SIZE_RATIO;
586 } else if (!refcount_cache_size_set) {
587 *refcount_cache_size = *l2_cache_size
588 / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
589 }
590 }
591 }
592
593 typedef struct Qcow2ReopenState {
594 Qcow2Cache *l2_table_cache;
595 Qcow2Cache *refcount_block_cache;
596 bool use_lazy_refcounts;
597 int overlap_check;
598 bool discard_passthrough[QCOW2_DISCARD_MAX];
599 uint64_t cache_clean_interval;
600 } Qcow2ReopenState;
601
602 static int qcow2_update_options_prepare(BlockDriverState *bs,
603 Qcow2ReopenState *r,
604 QDict *options, int flags,
605 Error **errp)
606 {
607 BDRVQcow2State *s = bs->opaque;
608 QemuOpts *opts = NULL;
609 const char *opt_overlap_check, *opt_overlap_check_template;
610 int overlap_check_template = 0;
611 uint64_t l2_cache_size, refcount_cache_size;
612 int i;
613 Error *local_err = NULL;
614 int ret;
615
616 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
617 qemu_opts_absorb_qdict(opts, options, &local_err);
618 if (local_err) {
619 error_propagate(errp, local_err);
620 ret = -EINVAL;
621 goto fail;
622 }
623
624 /* get L2 table/refcount block cache size from command line options */
625 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size,
626 &local_err);
627 if (local_err) {
628 error_propagate(errp, local_err);
629 ret = -EINVAL;
630 goto fail;
631 }
632
633 l2_cache_size /= s->cluster_size;
634 if (l2_cache_size < MIN_L2_CACHE_SIZE) {
635 l2_cache_size = MIN_L2_CACHE_SIZE;
636 }
637 if (l2_cache_size > INT_MAX) {
638 error_setg(errp, "L2 cache size too big");
639 ret = -EINVAL;
640 goto fail;
641 }
642
643 refcount_cache_size /= s->cluster_size;
644 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) {
645 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE;
646 }
647 if (refcount_cache_size > INT_MAX) {
648 error_setg(errp, "Refcount cache size too big");
649 ret = -EINVAL;
650 goto fail;
651 }
652
653 /* alloc new L2 table/refcount block cache, flush old one */
654 if (s->l2_table_cache) {
655 ret = qcow2_cache_flush(bs, s->l2_table_cache);
656 if (ret) {
657 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache");
658 goto fail;
659 }
660 }
661
662 if (s->refcount_block_cache) {
663 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
664 if (ret) {
665 error_setg_errno(errp, -ret,
666 "Failed to flush the refcount block cache");
667 goto fail;
668 }
669 }
670
671 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size);
672 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size);
673 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) {
674 error_setg(errp, "Could not allocate metadata caches");
675 ret = -ENOMEM;
676 goto fail;
677 }
678
679 /* New interval for cache cleanup timer */
680 r->cache_clean_interval =
681 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL,
682 s->cache_clean_interval);
683 if (r->cache_clean_interval > UINT_MAX) {
684 error_setg(errp, "Cache clean interval too big");
685 ret = -EINVAL;
686 goto fail;
687 }
688
689 /* lazy-refcounts; flush if going from enabled to disabled */
690 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
691 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
692 if (r->use_lazy_refcounts && s->qcow_version < 3) {
693 error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
694 "qemu 1.1 compatibility level");
695 ret = -EINVAL;
696 goto fail;
697 }
698
699 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) {
700 ret = qcow2_mark_clean(bs);
701 if (ret < 0) {
702 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts");
703 goto fail;
704 }
705 }
706
707 /* Overlap check options */
708 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
709 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
710 if (opt_overlap_check_template && opt_overlap_check &&
711 strcmp(opt_overlap_check_template, opt_overlap_check))
712 {
713 error_setg(errp, "Conflicting values for qcow2 options '"
714 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
715 "' ('%s')", opt_overlap_check, opt_overlap_check_template);
716 ret = -EINVAL;
717 goto fail;
718 }
719 if (!opt_overlap_check) {
720 opt_overlap_check = opt_overlap_check_template ?: "cached";
721 }
722
723 if (!strcmp(opt_overlap_check, "none")) {
724 overlap_check_template = 0;
725 } else if (!strcmp(opt_overlap_check, "constant")) {
726 overlap_check_template = QCOW2_OL_CONSTANT;
727 } else if (!strcmp(opt_overlap_check, "cached")) {
728 overlap_check_template = QCOW2_OL_CACHED;
729 } else if (!strcmp(opt_overlap_check, "all")) {
730 overlap_check_template = QCOW2_OL_ALL;
731 } else {
732 error_setg(errp, "Unsupported value '%s' for qcow2 option "
733 "'overlap-check'. Allowed are any of the following: "
734 "none, constant, cached, all", opt_overlap_check);
735 ret = -EINVAL;
736 goto fail;
737 }
738
739 r->overlap_check = 0;
740 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
741 /* overlap-check defines a template bitmask, but every flag may be
742 * overwritten through the associated boolean option */
743 r->overlap_check |=
744 qemu_opt_get_bool(opts, overlap_bool_option_names[i],
745 overlap_check_template & (1 << i)) << i;
746 }
747
748 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
749 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
750 r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
751 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
752 flags & BDRV_O_UNMAP);
753 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
754 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
755 r->discard_passthrough[QCOW2_DISCARD_OTHER] =
756 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
757
758 ret = 0;
759 fail:
760 qemu_opts_del(opts);
761 opts = NULL;
762 return ret;
763 }
764
765 static void qcow2_update_options_commit(BlockDriverState *bs,
766 Qcow2ReopenState *r)
767 {
768 BDRVQcow2State *s = bs->opaque;
769 int i;
770
771 if (s->l2_table_cache) {
772 qcow2_cache_destroy(bs, s->l2_table_cache);
773 }
774 if (s->refcount_block_cache) {
775 qcow2_cache_destroy(bs, s->refcount_block_cache);
776 }
777 s->l2_table_cache = r->l2_table_cache;
778 s->refcount_block_cache = r->refcount_block_cache;
779
780 s->overlap_check = r->overlap_check;
781 s->use_lazy_refcounts = r->use_lazy_refcounts;
782
783 for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
784 s->discard_passthrough[i] = r->discard_passthrough[i];
785 }
786
787 if (s->cache_clean_interval != r->cache_clean_interval) {
788 cache_clean_timer_del(bs);
789 s->cache_clean_interval = r->cache_clean_interval;
790 cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
791 }
792 }
793
794 static void qcow2_update_options_abort(BlockDriverState *bs,
795 Qcow2ReopenState *r)
796 {
797 if (r->l2_table_cache) {
798 qcow2_cache_destroy(bs, r->l2_table_cache);
799 }
800 if (r->refcount_block_cache) {
801 qcow2_cache_destroy(bs, r->refcount_block_cache);
802 }
803 }
804
805 static int qcow2_update_options(BlockDriverState *bs, QDict *options,
806 int flags, Error **errp)
807 {
808 Qcow2ReopenState r = {};
809 int ret;
810
811 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
812 if (ret >= 0) {
813 qcow2_update_options_commit(bs, &r);
814 } else {
815 qcow2_update_options_abort(bs, &r);
816 }
817
818 return ret;
819 }
820
821 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
822 Error **errp)
823 {
824 BDRVQcow2State *s = bs->opaque;
825 unsigned int len, i;
826 int ret = 0;
827 QCowHeader header;
828 Error *local_err = NULL;
829 uint64_t ext_end;
830 uint64_t l1_vm_state_index;
831
832 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header));
833 if (ret < 0) {
834 error_setg_errno(errp, -ret, "Could not read qcow2 header");
835 goto fail;
836 }
837 be32_to_cpus(&header.magic);
838 be32_to_cpus(&header.version);
839 be64_to_cpus(&header.backing_file_offset);
840 be32_to_cpus(&header.backing_file_size);
841 be64_to_cpus(&header.size);
842 be32_to_cpus(&header.cluster_bits);
843 be32_to_cpus(&header.crypt_method);
844 be64_to_cpus(&header.l1_table_offset);
845 be32_to_cpus(&header.l1_size);
846 be64_to_cpus(&header.refcount_table_offset);
847 be32_to_cpus(&header.refcount_table_clusters);
848 be64_to_cpus(&header.snapshots_offset);
849 be32_to_cpus(&header.nb_snapshots);
850
851 if (header.magic != QCOW_MAGIC) {
852 error_setg(errp, "Image is not in qcow2 format");
853 ret = -EINVAL;
854 goto fail;
855 }
856 if (header.version < 2 || header.version > 3) {
857 report_unsupported(bs, errp, "QCOW version %" PRIu32, header.version);
858 ret = -ENOTSUP;
859 goto fail;
860 }
861
862 s->qcow_version = header.version;
863
864 /* Initialise cluster size */
865 if (header.cluster_bits < MIN_CLUSTER_BITS ||
866 header.cluster_bits > MAX_CLUSTER_BITS) {
867 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
868 header.cluster_bits);
869 ret = -EINVAL;
870 goto fail;
871 }
872
873 s->cluster_bits = header.cluster_bits;
874 s->cluster_size = 1 << s->cluster_bits;
875 s->cluster_sectors = 1 << (s->cluster_bits - 9);
876
877 /* Initialise version 3 header fields */
878 if (header.version == 2) {
879 header.incompatible_features = 0;
880 header.compatible_features = 0;
881 header.autoclear_features = 0;
882 header.refcount_order = 4;
883 header.header_length = 72;
884 } else {
885 be64_to_cpus(&header.incompatible_features);
886 be64_to_cpus(&header.compatible_features);
887 be64_to_cpus(&header.autoclear_features);
888 be32_to_cpus(&header.refcount_order);
889 be32_to_cpus(&header.header_length);
890
891 if (header.header_length < 104) {
892 error_setg(errp, "qcow2 header too short");
893 ret = -EINVAL;
894 goto fail;
895 }
896 }
897
898 if (header.header_length > s->cluster_size) {
899 error_setg(errp, "qcow2 header exceeds cluster size");
900 ret = -EINVAL;
901 goto fail;
902 }
903
904 if (header.header_length > sizeof(header)) {
905 s->unknown_header_fields_size = header.header_length - sizeof(header);
906 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
907 ret = bdrv_pread(bs->file->bs, sizeof(header), s->unknown_header_fields,
908 s->unknown_header_fields_size);
909 if (ret < 0) {
910 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
911 "fields");
912 goto fail;
913 }
914 }
915
916 if (header.backing_file_offset > s->cluster_size) {
917 error_setg(errp, "Invalid backing file offset");
918 ret = -EINVAL;
919 goto fail;
920 }
921
922 if (header.backing_file_offset) {
923 ext_end = header.backing_file_offset;
924 } else {
925 ext_end = 1 << header.cluster_bits;
926 }
927
928 /* Handle feature bits */
929 s->incompatible_features = header.incompatible_features;
930 s->compatible_features = header.compatible_features;
931 s->autoclear_features = header.autoclear_features;
932
933 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
934 void *feature_table = NULL;
935 qcow2_read_extensions(bs, header.header_length, ext_end,
936 &feature_table, NULL);
937 report_unsupported_feature(bs, errp, feature_table,
938 s->incompatible_features &
939 ~QCOW2_INCOMPAT_MASK);
940 ret = -ENOTSUP;
941 g_free(feature_table);
942 goto fail;
943 }
944
945 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
946 /* Corrupt images may not be written to unless they are being repaired
947 */
948 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
949 error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
950 "read/write");
951 ret = -EACCES;
952 goto fail;
953 }
954 }
955
956 /* Check support for various header values */
957 if (header.refcount_order > 6) {
958 error_setg(errp, "Reference count entry width too large; may not "
959 "exceed 64 bits");
960 ret = -EINVAL;
961 goto fail;
962 }
963 s->refcount_order = header.refcount_order;
964 s->refcount_bits = 1 << s->refcount_order;
965 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
966 s->refcount_max += s->refcount_max - 1;
967
968 if (header.crypt_method > QCOW_CRYPT_AES) {
969 error_setg(errp, "Unsupported encryption method: %" PRIu32,
970 header.crypt_method);
971 ret = -EINVAL;
972 goto fail;
973 }
974 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
975 error_setg(errp, "AES cipher not available");
976 ret = -EINVAL;
977 goto fail;
978 }
979 s->crypt_method_header = header.crypt_method;
980 if (s->crypt_method_header) {
981 bs->encrypted = 1;
982 }
983
984 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
985 s->l2_size = 1 << s->l2_bits;
986 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
987 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
988 s->refcount_block_size = 1 << s->refcount_block_bits;
989 bs->total_sectors = header.size / 512;
990 s->csize_shift = (62 - (s->cluster_bits - 8));
991 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
992 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
993
994 s->refcount_table_offset = header.refcount_table_offset;
995 s->refcount_table_size =
996 header.refcount_table_clusters << (s->cluster_bits - 3);
997
998 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) {
999 error_setg(errp, "Reference count table too large");
1000 ret = -EINVAL;
1001 goto fail;
1002 }
1003
1004 ret = validate_table_offset(bs, s->refcount_table_offset,
1005 s->refcount_table_size, sizeof(uint64_t));
1006 if (ret < 0) {
1007 error_setg(errp, "Invalid reference count table offset");
1008 goto fail;
1009 }
1010
1011 /* Snapshot table offset/length */
1012 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) {
1013 error_setg(errp, "Too many snapshots");
1014 ret = -EINVAL;
1015 goto fail;
1016 }
1017
1018 ret = validate_table_offset(bs, header.snapshots_offset,
1019 header.nb_snapshots,
1020 sizeof(QCowSnapshotHeader));
1021 if (ret < 0) {
1022 error_setg(errp, "Invalid snapshot table offset");
1023 goto fail;
1024 }
1025
1026 /* read the level 1 table */
1027 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
1028 error_setg(errp, "Active L1 table too large");
1029 ret = -EFBIG;
1030 goto fail;
1031 }
1032 s->l1_size = header.l1_size;
1033
1034 l1_vm_state_index = size_to_l1(s, header.size);
1035 if (l1_vm_state_index > INT_MAX) {
1036 error_setg(errp, "Image is too big");
1037 ret = -EFBIG;
1038 goto fail;
1039 }
1040 s->l1_vm_state_index = l1_vm_state_index;
1041
1042 /* the L1 table must contain at least enough entries to put
1043 header.size bytes */
1044 if (s->l1_size < s->l1_vm_state_index) {
1045 error_setg(errp, "L1 table is too small");
1046 ret = -EINVAL;
1047 goto fail;
1048 }
1049
1050 ret = validate_table_offset(bs, header.l1_table_offset,
1051 header.l1_size, sizeof(uint64_t));
1052 if (ret < 0) {
1053 error_setg(errp, "Invalid L1 table offset");
1054 goto fail;
1055 }
1056 s->l1_table_offset = header.l1_table_offset;
1057
1058
1059 if (s->l1_size > 0) {
1060 s->l1_table = qemu_try_blockalign(bs->file->bs,
1061 align_offset(s->l1_size * sizeof(uint64_t), 512));
1062 if (s->l1_table == NULL) {
1063 error_setg(errp, "Could not allocate L1 table");
1064 ret = -ENOMEM;
1065 goto fail;
1066 }
1067 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table,
1068 s->l1_size * sizeof(uint64_t));
1069 if (ret < 0) {
1070 error_setg_errno(errp, -ret, "Could not read L1 table");
1071 goto fail;
1072 }
1073 for(i = 0;i < s->l1_size; i++) {
1074 be64_to_cpus(&s->l1_table[i]);
1075 }
1076 }
1077
1078 /* Parse driver-specific options */
1079 ret = qcow2_update_options(bs, options, flags, errp);
1080 if (ret < 0) {
1081 goto fail;
1082 }
1083
1084 s->cluster_cache = g_malloc(s->cluster_size);
1085 /* one more sector for decompressed data alignment */
1086 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS
1087 * s->cluster_size + 512);
1088 if (s->cluster_data == NULL) {
1089 error_setg(errp, "Could not allocate temporary cluster buffer");
1090 ret = -ENOMEM;
1091 goto fail;
1092 }
1093
1094 s->cluster_cache_offset = -1;
1095 s->flags = flags;
1096
1097 ret = qcow2_refcount_init(bs);
1098 if (ret != 0) {
1099 error_setg_errno(errp, -ret, "Could not initialize refcount handling");
1100 goto fail;
1101 }
1102
1103 QLIST_INIT(&s->cluster_allocs);
1104 QTAILQ_INIT(&s->discards);
1105
1106 /* read qcow2 extensions */
1107 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
1108 &local_err)) {
1109 error_propagate(errp, local_err);
1110 ret = -EINVAL;
1111 goto fail;
1112 }
1113
1114 /* read the backing file name */
1115 if (header.backing_file_offset != 0) {
1116 len = header.backing_file_size;
1117 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
1118 len >= sizeof(bs->backing_file)) {
1119 error_setg(errp, "Backing file name too long");
1120 ret = -EINVAL;
1121 goto fail;
1122 }
1123 ret = bdrv_pread(bs->file->bs, header.backing_file_offset,
1124 bs->backing_file, len);
1125 if (ret < 0) {
1126 error_setg_errno(errp, -ret, "Could not read backing file name");
1127 goto fail;
1128 }
1129 bs->backing_file[len] = '\0';
1130 s->image_backing_file = g_strdup(bs->backing_file);
1131 }
1132
1133 /* Internal snapshots */
1134 s->snapshots_offset = header.snapshots_offset;
1135 s->nb_snapshots = header.nb_snapshots;
1136
1137 ret = qcow2_read_snapshots(bs);
1138 if (ret < 0) {
1139 error_setg_errno(errp, -ret, "Could not read snapshots");
1140 goto fail;
1141 }
1142
1143 /* Clear unknown autoclear feature bits */
1144 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) {
1145 s->autoclear_features = 0;
1146 ret = qcow2_update_header(bs);
1147 if (ret < 0) {
1148 error_setg_errno(errp, -ret, "Could not update qcow2 header");
1149 goto fail;
1150 }
1151 }
1152
1153 /* Initialise locks */
1154 qemu_co_mutex_init(&s->lock);
1155
1156 /* Repair image if dirty */
1157 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
1158 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
1159 BdrvCheckResult result = {0};
1160
1161 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
1162 if (ret < 0) {
1163 error_setg_errno(errp, -ret, "Could not repair dirty image");
1164 goto fail;
1165 }
1166 }
1167
1168 #ifdef DEBUG_ALLOC
1169 {
1170 BdrvCheckResult result = {0};
1171 qcow2_check_refcounts(bs, &result, 0);
1172 }
1173 #endif
1174 return ret;
1175
1176 fail:
1177 g_free(s->unknown_header_fields);
1178 cleanup_unknown_header_ext(bs);
1179 qcow2_free_snapshots(bs);
1180 qcow2_refcount_close(bs);
1181 qemu_vfree(s->l1_table);
1182 /* else pre-write overlap checks in cache_destroy may crash */
1183 s->l1_table = NULL;
1184 cache_clean_timer_del(bs);
1185 if (s->l2_table_cache) {
1186 qcow2_cache_destroy(bs, s->l2_table_cache);
1187 }
1188 if (s->refcount_block_cache) {
1189 qcow2_cache_destroy(bs, s->refcount_block_cache);
1190 }
1191 g_free(s->cluster_cache);
1192 qemu_vfree(s->cluster_data);
1193 return ret;
1194 }
1195
1196 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
1197 {
1198 BDRVQcow2State *s = bs->opaque;
1199
1200 bs->bl.write_zeroes_alignment = s->cluster_sectors;
1201 }
1202
1203 static int qcow2_set_key(BlockDriverState *bs, const char *key)
1204 {
1205 BDRVQcow2State *s = bs->opaque;
1206 uint8_t keybuf[16];
1207 int len, i;
1208 Error *err = NULL;
1209
1210 memset(keybuf, 0, 16);
1211 len = strlen(key);
1212 if (len > 16)
1213 len = 16;
1214 /* XXX: we could compress the chars to 7 bits to increase
1215 entropy */
1216 for(i = 0;i < len;i++) {
1217 keybuf[i] = key[i];
1218 }
1219 assert(bs->encrypted);
1220
1221 qcrypto_cipher_free(s->cipher);
1222 s->cipher = qcrypto_cipher_new(
1223 QCRYPTO_CIPHER_ALG_AES_128,
1224 QCRYPTO_CIPHER_MODE_CBC,
1225 keybuf, G_N_ELEMENTS(keybuf),
1226 &err);
1227
1228 if (!s->cipher) {
1229 /* XXX would be nice if errors in this method could
1230 * be properly propagate to the caller. Would need
1231 * the bdrv_set_key() API signature to be fixed. */
1232 error_free(err);
1233 return -1;
1234 }
1235 return 0;
1236 }
1237
1238 static int qcow2_reopen_prepare(BDRVReopenState *state,
1239 BlockReopenQueue *queue, Error **errp)
1240 {
1241 Qcow2ReopenState *r;
1242 int ret;
1243
1244 r = g_new0(Qcow2ReopenState, 1);
1245 state->opaque = r;
1246
1247 ret = qcow2_update_options_prepare(state->bs, r, state->options,
1248 state->flags, errp);
1249 if (ret < 0) {
1250 goto fail;
1251 }
1252
1253 /* We need to write out any unwritten data if we reopen read-only. */
1254 if ((state->flags & BDRV_O_RDWR) == 0) {
1255 ret = bdrv_flush(state->bs);
1256 if (ret < 0) {
1257 goto fail;
1258 }
1259
1260 ret = qcow2_mark_clean(state->bs);
1261 if (ret < 0) {
1262 goto fail;
1263 }
1264 }
1265
1266 return 0;
1267
1268 fail:
1269 qcow2_update_options_abort(state->bs, r);
1270 g_free(r);
1271 return ret;
1272 }
1273
1274 static void qcow2_reopen_commit(BDRVReopenState *state)
1275 {
1276 qcow2_update_options_commit(state->bs, state->opaque);
1277 g_free(state->opaque);
1278 }
1279
1280 static void qcow2_reopen_abort(BDRVReopenState *state)
1281 {
1282 qcow2_update_options_abort(state->bs, state->opaque);
1283 g_free(state->opaque);
1284 }
1285
1286 static void qcow2_join_options(QDict *options, QDict *old_options)
1287 {
1288 bool has_new_overlap_template =
1289 qdict_haskey(options, QCOW2_OPT_OVERLAP) ||
1290 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);
1291 bool has_new_total_cache_size =
1292 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);
1293 bool has_all_cache_options;
1294
1295 /* New overlap template overrides all old overlap options */
1296 if (has_new_overlap_template) {
1297 qdict_del(old_options, QCOW2_OPT_OVERLAP);
1298 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);
1299 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);
1300 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);
1301 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);
1302 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);
1303 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);
1304 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);
1305 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);
1306 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);
1307 }
1308
1309 /* New total cache size overrides all old options */
1310 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {
1311 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);
1312 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1313 }
1314
1315 qdict_join(options, old_options, false);
1316
1317 /*
1318 * If after merging all cache size options are set, an old total size is
1319 * overwritten. Do keep all options, however, if all three are new. The
1320 * resulting error message is what we want to happen.
1321 */
1322 has_all_cache_options =
1323 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||
1324 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||
1325 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1326
1327 if (has_all_cache_options && !has_new_total_cache_size) {
1328 qdict_del(options, QCOW2_OPT_CACHE_SIZE);
1329 }
1330 }
1331
1332 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
1333 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
1334 {
1335 BDRVQcow2State *s = bs->opaque;
1336 uint64_t cluster_offset;
1337 int index_in_cluster, ret;
1338 int64_t status = 0;
1339
1340 *pnum = nb_sectors;
1341 qemu_co_mutex_lock(&s->lock);
1342 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
1343 qemu_co_mutex_unlock(&s->lock);
1344 if (ret < 0) {
1345 return ret;
1346 }
1347
1348 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED &&
1349 !s->cipher) {
1350 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1351 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
1352 *file = bs->file->bs;
1353 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset;
1354 }
1355 if (ret == QCOW2_CLUSTER_ZERO) {
1356 status |= BDRV_BLOCK_ZERO;
1357 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
1358 status |= BDRV_BLOCK_DATA;
1359 }
1360 return status;
1361 }
1362
1363 /* handle reading after the end of the backing file */
1364 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
1365 int64_t sector_num, int nb_sectors)
1366 {
1367 int n1;
1368 if ((sector_num + nb_sectors) <= bs->total_sectors)
1369 return nb_sectors;
1370 if (sector_num >= bs->total_sectors)
1371 n1 = 0;
1372 else
1373 n1 = bs->total_sectors - sector_num;
1374
1375 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1));
1376
1377 return n1;
1378 }
1379
1380 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
1381 int remaining_sectors, QEMUIOVector *qiov)
1382 {
1383 BDRVQcow2State *s = bs->opaque;
1384 int index_in_cluster, n1;
1385 int ret;
1386 int cur_nr_sectors; /* number of sectors in current iteration */
1387 uint64_t cluster_offset = 0;
1388 uint64_t bytes_done = 0;
1389 QEMUIOVector hd_qiov;
1390 uint8_t *cluster_data = NULL;
1391
1392 qemu_iovec_init(&hd_qiov, qiov->niov);
1393
1394 qemu_co_mutex_lock(&s->lock);
1395
1396 while (remaining_sectors != 0) {
1397
1398 /* prepare next request */
1399 cur_nr_sectors = remaining_sectors;
1400 if (s->cipher) {
1401 cur_nr_sectors = MIN(cur_nr_sectors,
1402 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
1403 }
1404
1405 ret = qcow2_get_cluster_offset(bs, sector_num << 9,
1406 &cur_nr_sectors, &cluster_offset);
1407 if (ret < 0) {
1408 goto fail;
1409 }
1410
1411 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1412
1413 qemu_iovec_reset(&hd_qiov);
1414 qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1415 cur_nr_sectors * 512);
1416
1417 switch (ret) {
1418 case QCOW2_CLUSTER_UNALLOCATED:
1419
1420 if (bs->backing) {
1421 /* read from the base image */
1422 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov,
1423 sector_num, cur_nr_sectors);
1424 if (n1 > 0) {
1425 QEMUIOVector local_qiov;
1426
1427 qemu_iovec_init(&local_qiov, hd_qiov.niov);
1428 qemu_iovec_concat(&local_qiov, &hd_qiov, 0,
1429 n1 * BDRV_SECTOR_SIZE);
1430
1431 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
1432 qemu_co_mutex_unlock(&s->lock);
1433 ret = bdrv_co_readv(bs->backing->bs, sector_num,
1434 n1, &local_qiov);
1435 qemu_co_mutex_lock(&s->lock);
1436
1437 qemu_iovec_destroy(&local_qiov);
1438
1439 if (ret < 0) {
1440 goto fail;
1441 }
1442 }
1443 } else {
1444 /* Note: in this case, no need to wait */
1445 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
1446 }
1447 break;
1448
1449 case QCOW2_CLUSTER_ZERO:
1450 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
1451 break;
1452
1453 case QCOW2_CLUSTER_COMPRESSED:
1454 /* add AIO support for compressed blocks ? */
1455 ret = qcow2_decompress_cluster(bs, cluster_offset);
1456 if (ret < 0) {
1457 goto fail;
1458 }
1459
1460 qemu_iovec_from_buf(&hd_qiov, 0,
1461 s->cluster_cache + index_in_cluster * 512,
1462 512 * cur_nr_sectors);
1463 break;
1464
1465 case QCOW2_CLUSTER_NORMAL:
1466 if ((cluster_offset & 511) != 0) {
1467 ret = -EIO;
1468 goto fail;
1469 }
1470
1471 if (bs->encrypted) {
1472 assert(s->cipher);
1473
1474 /*
1475 * For encrypted images, read everything into a temporary
1476 * contiguous buffer on which the AES functions can work.
1477 */
1478 if (!cluster_data) {
1479 cluster_data =
1480 qemu_try_blockalign(bs->file->bs,
1481 QCOW_MAX_CRYPT_CLUSTERS
1482 * s->cluster_size);
1483 if (cluster_data == NULL) {
1484 ret = -ENOMEM;
1485 goto fail;
1486 }
1487 }
1488
1489 assert(cur_nr_sectors <=
1490 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
1491 qemu_iovec_reset(&hd_qiov);
1492 qemu_iovec_add(&hd_qiov, cluster_data,
1493 512 * cur_nr_sectors);
1494 }
1495
1496 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
1497 qemu_co_mutex_unlock(&s->lock);
1498 ret = bdrv_co_readv(bs->file->bs,
1499 (cluster_offset >> 9) + index_in_cluster,
1500 cur_nr_sectors, &hd_qiov);
1501 qemu_co_mutex_lock(&s->lock);
1502 if (ret < 0) {
1503 goto fail;
1504 }
1505 if (bs->encrypted) {
1506 assert(s->cipher);
1507 Error *err = NULL;
1508 if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
1509 cluster_data, cur_nr_sectors, false,
1510 &err) < 0) {
1511 error_free(err);
1512 ret = -EIO;
1513 goto fail;
1514 }
1515 qemu_iovec_from_buf(qiov, bytes_done,
1516 cluster_data, 512 * cur_nr_sectors);
1517 }
1518 break;
1519
1520 default:
1521 g_assert_not_reached();
1522 ret = -EIO;
1523 goto fail;
1524 }
1525
1526 remaining_sectors -= cur_nr_sectors;
1527 sector_num += cur_nr_sectors;
1528 bytes_done += cur_nr_sectors * 512;
1529 }
1530 ret = 0;
1531
1532 fail:
1533 qemu_co_mutex_unlock(&s->lock);
1534
1535 qemu_iovec_destroy(&hd_qiov);
1536 qemu_vfree(cluster_data);
1537
1538 return ret;
1539 }
1540
1541 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
1542 int64_t sector_num,
1543 int remaining_sectors,
1544 QEMUIOVector *qiov)
1545 {
1546 BDRVQcow2State *s = bs->opaque;
1547 int index_in_cluster;
1548 int ret;
1549 int cur_nr_sectors; /* number of sectors in current iteration */
1550 uint64_t cluster_offset;
1551 QEMUIOVector hd_qiov;
1552 uint64_t bytes_done = 0;
1553 uint8_t *cluster_data = NULL;
1554 QCowL2Meta *l2meta = NULL;
1555
1556 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num,
1557 remaining_sectors);
1558
1559 qemu_iovec_init(&hd_qiov, qiov->niov);
1560
1561 s->cluster_cache_offset = -1; /* disable compressed cache */
1562
1563 qemu_co_mutex_lock(&s->lock);
1564
1565 while (remaining_sectors != 0) {
1566
1567 l2meta = NULL;
1568
1569 trace_qcow2_writev_start_part(qemu_coroutine_self());
1570 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1571 cur_nr_sectors = remaining_sectors;
1572 if (bs->encrypted &&
1573 cur_nr_sectors >
1574 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) {
1575 cur_nr_sectors =
1576 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster;
1577 }
1578
1579 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,
1580 &cur_nr_sectors, &cluster_offset, &l2meta);
1581 if (ret < 0) {
1582 goto fail;
1583 }
1584
1585 assert((cluster_offset & 511) == 0);
1586
1587 qemu_iovec_reset(&hd_qiov);
1588 qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1589 cur_nr_sectors * 512);
1590
1591 if (bs->encrypted) {
1592 Error *err = NULL;
1593 assert(s->cipher);
1594 if (!cluster_data) {
1595 cluster_data = qemu_try_blockalign(bs->file->bs,
1596 QCOW_MAX_CRYPT_CLUSTERS
1597 * s->cluster_size);
1598 if (cluster_data == NULL) {
1599 ret = -ENOMEM;
1600 goto fail;
1601 }
1602 }
1603
1604 assert(hd_qiov.size <=
1605 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1606 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
1607
1608 if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
1609 cluster_data, cur_nr_sectors,
1610 true, &err) < 0) {
1611 error_free(err);
1612 ret = -EIO;
1613 goto fail;
1614 }
1615
1616 qemu_iovec_reset(&hd_qiov);
1617 qemu_iovec_add(&hd_qiov, cluster_data,
1618 cur_nr_sectors * 512);
1619 }
1620
1621 ret = qcow2_pre_write_overlap_check(bs, 0,
1622 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE,
1623 cur_nr_sectors * BDRV_SECTOR_SIZE);
1624 if (ret < 0) {
1625 goto fail;
1626 }
1627
1628 qemu_co_mutex_unlock(&s->lock);
1629 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
1630 trace_qcow2_writev_data(qemu_coroutine_self(),
1631 (cluster_offset >> 9) + index_in_cluster);
1632 ret = bdrv_co_writev(bs->file->bs,
1633 (cluster_offset >> 9) + index_in_cluster,
1634 cur_nr_sectors, &hd_qiov);
1635 qemu_co_mutex_lock(&s->lock);
1636 if (ret < 0) {
1637 goto fail;
1638 }
1639
1640 while (l2meta != NULL) {
1641 QCowL2Meta *next;
1642
1643 ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
1644 if (ret < 0) {
1645 goto fail;
1646 }
1647
1648 /* Take the request off the list of running requests */
1649 if (l2meta->nb_clusters != 0) {
1650 QLIST_REMOVE(l2meta, next_in_flight);
1651 }
1652
1653 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1654
1655 next = l2meta->next;
1656 g_free(l2meta);
1657 l2meta = next;
1658 }
1659
1660 remaining_sectors -= cur_nr_sectors;
1661 sector_num += cur_nr_sectors;
1662 bytes_done += cur_nr_sectors * 512;
1663 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors);
1664 }
1665 ret = 0;
1666
1667 fail:
1668 qemu_co_mutex_unlock(&s->lock);
1669
1670 while (l2meta != NULL) {
1671 QCowL2Meta *next;
1672
1673 if (l2meta->nb_clusters != 0) {
1674 QLIST_REMOVE(l2meta, next_in_flight);
1675 }
1676 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1677
1678 next = l2meta->next;
1679 g_free(l2meta);
1680 l2meta = next;
1681 }
1682
1683 qemu_iovec_destroy(&hd_qiov);
1684 qemu_vfree(cluster_data);
1685 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
1686
1687 return ret;
1688 }
1689
1690 static int qcow2_inactivate(BlockDriverState *bs)
1691 {
1692 BDRVQcow2State *s = bs->opaque;
1693 int ret, result = 0;
1694
1695 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1696 if (ret) {
1697 result = ret;
1698 error_report("Failed to flush the L2 table cache: %s",
1699 strerror(-ret));
1700 }
1701
1702 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1703 if (ret) {
1704 result = ret;
1705 error_report("Failed to flush the refcount block cache: %s",
1706 strerror(-ret));
1707 }
1708
1709 if (result == 0) {
1710 qcow2_mark_clean(bs);
1711 }
1712
1713 return result;
1714 }
1715
1716 static void qcow2_close(BlockDriverState *bs)
1717 {
1718 BDRVQcow2State *s = bs->opaque;
1719 qemu_vfree(s->l1_table);
1720 /* else pre-write overlap checks in cache_destroy may crash */
1721 s->l1_table = NULL;
1722
1723 if (!(s->flags & BDRV_O_INACTIVE)) {
1724 qcow2_inactivate(bs);
1725 }
1726
1727 cache_clean_timer_del(bs);
1728 qcow2_cache_destroy(bs, s->l2_table_cache);
1729 qcow2_cache_destroy(bs, s->refcount_block_cache);
1730
1731 qcrypto_cipher_free(s->cipher);
1732 s->cipher = NULL;
1733
1734 g_free(s->unknown_header_fields);
1735 cleanup_unknown_header_ext(bs);
1736
1737 g_free(s->image_backing_file);
1738 g_free(s->image_backing_format);
1739
1740 g_free(s->cluster_cache);
1741 qemu_vfree(s->cluster_data);
1742 qcow2_refcount_close(bs);
1743 qcow2_free_snapshots(bs);
1744 }
1745
1746 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
1747 {
1748 BDRVQcow2State *s = bs->opaque;
1749 int flags = s->flags;
1750 QCryptoCipher *cipher = NULL;
1751 QDict *options;
1752 Error *local_err = NULL;
1753 int ret;
1754
1755 /*
1756 * Backing files are read-only which makes all of their metadata immutable,
1757 * that means we don't have to worry about reopening them here.
1758 */
1759
1760 cipher = s->cipher;
1761 s->cipher = NULL;
1762
1763 qcow2_close(bs);
1764
1765 bdrv_invalidate_cache(bs->file->bs, &local_err);
1766 if (local_err) {
1767 error_propagate(errp, local_err);
1768 bs->drv = NULL;
1769 return;
1770 }
1771
1772 memset(s, 0, sizeof(BDRVQcow2State));
1773 options = qdict_clone_shallow(bs->options);
1774
1775 flags &= ~BDRV_O_INACTIVE;
1776 ret = qcow2_open(bs, options, flags, &local_err);
1777 QDECREF(options);
1778 if (local_err) {
1779 error_propagate(errp, local_err);
1780 error_prepend(errp, "Could not reopen qcow2 layer: ");
1781 bs->drv = NULL;
1782 return;
1783 } else if (ret < 0) {
1784 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
1785 bs->drv = NULL;
1786 return;
1787 }
1788
1789 s->cipher = cipher;
1790 }
1791
1792 static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
1793 size_t len, size_t buflen)
1794 {
1795 QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
1796 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
1797
1798 if (buflen < ext_len) {
1799 return -ENOSPC;
1800 }
1801
1802 *ext_backing_fmt = (QCowExtension) {
1803 .magic = cpu_to_be32(magic),
1804 .len = cpu_to_be32(len),
1805 };
1806 memcpy(buf + sizeof(QCowExtension), s, len);
1807
1808 return ext_len;
1809 }
1810
1811 /*
1812 * Updates the qcow2 header, including the variable length parts of it, i.e.
1813 * the backing file name and all extensions. qcow2 was not designed to allow
1814 * such changes, so if we run out of space (we can only use the first cluster)
1815 * this function may fail.
1816 *
1817 * Returns 0 on success, -errno in error cases.
1818 */
1819 int qcow2_update_header(BlockDriverState *bs)
1820 {
1821 BDRVQcow2State *s = bs->opaque;
1822 QCowHeader *header;
1823 char *buf;
1824 size_t buflen = s->cluster_size;
1825 int ret;
1826 uint64_t total_size;
1827 uint32_t refcount_table_clusters;
1828 size_t header_length;
1829 Qcow2UnknownHeaderExtension *uext;
1830
1831 buf = qemu_blockalign(bs, buflen);
1832
1833 /* Header structure */
1834 header = (QCowHeader*) buf;
1835
1836 if (buflen < sizeof(*header)) {
1837 ret = -ENOSPC;
1838 goto fail;
1839 }
1840
1841 header_length = sizeof(*header) + s->unknown_header_fields_size;
1842 total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
1843 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
1844
1845 *header = (QCowHeader) {
1846 /* Version 2 fields */
1847 .magic = cpu_to_be32(QCOW_MAGIC),
1848 .version = cpu_to_be32(s->qcow_version),
1849 .backing_file_offset = 0,
1850 .backing_file_size = 0,
1851 .cluster_bits = cpu_to_be32(s->cluster_bits),
1852 .size = cpu_to_be64(total_size),
1853 .crypt_method = cpu_to_be32(s->crypt_method_header),
1854 .l1_size = cpu_to_be32(s->l1_size),
1855 .l1_table_offset = cpu_to_be64(s->l1_table_offset),
1856 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
1857 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
1858 .nb_snapshots = cpu_to_be32(s->nb_snapshots),
1859 .snapshots_offset = cpu_to_be64(s->snapshots_offset),
1860
1861 /* Version 3 fields */
1862 .incompatible_features = cpu_to_be64(s->incompatible_features),
1863 .compatible_features = cpu_to_be64(s->compatible_features),
1864 .autoclear_features = cpu_to_be64(s->autoclear_features),
1865 .refcount_order = cpu_to_be32(s->refcount_order),
1866 .header_length = cpu_to_be32(header_length),
1867 };
1868
1869 /* For older versions, write a shorter header */
1870 switch (s->qcow_version) {
1871 case 2:
1872 ret = offsetof(QCowHeader, incompatible_features);
1873 break;
1874 case 3:
1875 ret = sizeof(*header);
1876 break;
1877 default:
1878 ret = -EINVAL;
1879 goto fail;
1880 }
1881
1882 buf += ret;
1883 buflen -= ret;
1884 memset(buf, 0, buflen);
1885
1886 /* Preserve any unknown field in the header */
1887 if (s->unknown_header_fields_size) {
1888 if (buflen < s->unknown_header_fields_size) {
1889 ret = -ENOSPC;
1890 goto fail;
1891 }
1892
1893 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
1894 buf += s->unknown_header_fields_size;
1895 buflen -= s->unknown_header_fields_size;
1896 }
1897
1898 /* Backing file format header extension */
1899 if (s->image_backing_format) {
1900 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
1901 s->image_backing_format,
1902 strlen(s->image_backing_format),
1903 buflen);
1904 if (ret < 0) {
1905 goto fail;
1906 }
1907
1908 buf += ret;
1909 buflen -= ret;
1910 }
1911
1912 /* Feature table */
1913 if (s->qcow_version >= 3) {
1914 Qcow2Feature features[] = {
1915 {
1916 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1917 .bit = QCOW2_INCOMPAT_DIRTY_BITNR,
1918 .name = "dirty bit",
1919 },
1920 {
1921 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1922 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
1923 .name = "corrupt bit",
1924 },
1925 {
1926 .type = QCOW2_FEAT_TYPE_COMPATIBLE,
1927 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
1928 .name = "lazy refcounts",
1929 },
1930 };
1931
1932 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
1933 features, sizeof(features), buflen);
1934 if (ret < 0) {
1935 goto fail;
1936 }
1937 buf += ret;
1938 buflen -= ret;
1939 }
1940
1941 /* Keep unknown header extensions */
1942 QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
1943 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
1944 if (ret < 0) {
1945 goto fail;
1946 }
1947
1948 buf += ret;
1949 buflen -= ret;
1950 }
1951
1952 /* End of header extensions */
1953 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
1954 if (ret < 0) {
1955 goto fail;
1956 }
1957
1958 buf += ret;
1959 buflen -= ret;
1960
1961 /* Backing file name */
1962 if (s->image_backing_file) {
1963 size_t backing_file_len = strlen(s->image_backing_file);
1964
1965 if (buflen < backing_file_len) {
1966 ret = -ENOSPC;
1967 goto fail;
1968 }
1969
1970 /* Using strncpy is ok here, since buf is not NUL-terminated. */
1971 strncpy(buf, s->image_backing_file, buflen);
1972
1973 header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
1974 header->backing_file_size = cpu_to_be32(backing_file_len);
1975 }
1976
1977 /* Write the new header */
1978 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size);
1979 if (ret < 0) {
1980 goto fail;
1981 }
1982
1983 ret = 0;
1984 fail:
1985 qemu_vfree(header);
1986 return ret;
1987 }
1988
1989 static int qcow2_change_backing_file(BlockDriverState *bs,
1990 const char *backing_file, const char *backing_fmt)
1991 {
1992 BDRVQcow2State *s = bs->opaque;
1993
1994 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
1995 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
1996
1997 g_free(s->image_backing_file);
1998 g_free(s->image_backing_format);
1999
2000 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
2001 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
2002
2003 return qcow2_update_header(bs);
2004 }
2005
2006 static int preallocate(BlockDriverState *bs)
2007 {
2008 uint64_t nb_sectors;
2009 uint64_t offset;
2010 uint64_t host_offset = 0;
2011 int num;
2012 int ret;
2013 QCowL2Meta *meta;
2014
2015 nb_sectors = bdrv_nb_sectors(bs);
2016 offset = 0;
2017
2018 while (nb_sectors) {
2019 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS);
2020 ret = qcow2_alloc_cluster_offset(bs, offset, &num,
2021 &host_offset, &meta);
2022 if (ret < 0) {
2023 return ret;
2024 }
2025
2026 while (meta) {
2027 QCowL2Meta *next = meta->next;
2028
2029 ret = qcow2_alloc_cluster_link_l2(bs, meta);
2030 if (ret < 0) {
2031 qcow2_free_any_clusters(bs, meta->alloc_offset,
2032 meta->nb_clusters, QCOW2_DISCARD_NEVER);
2033 return ret;
2034 }
2035
2036 /* There are no dependent requests, but we need to remove our
2037 * request from the list of in-flight requests */
2038 QLIST_REMOVE(meta, next_in_flight);
2039
2040 g_free(meta);
2041 meta = next;
2042 }
2043
2044 /* TODO Preallocate data if requested */
2045
2046 nb_sectors -= num;
2047 offset += num << BDRV_SECTOR_BITS;
2048 }
2049
2050 /*
2051 * It is expected that the image file is large enough to actually contain
2052 * all of the allocated clusters (otherwise we get failing reads after
2053 * EOF). Extend the image to the last allocated sector.
2054 */
2055 if (host_offset != 0) {
2056 uint8_t buf[BDRV_SECTOR_SIZE];
2057 memset(buf, 0, BDRV_SECTOR_SIZE);
2058 ret = bdrv_write(bs->file->bs,
2059 (host_offset >> BDRV_SECTOR_BITS) + num - 1,
2060 buf, 1);
2061 if (ret < 0) {
2062 return ret;
2063 }
2064 }
2065
2066 return 0;
2067 }
2068
2069 static int qcow2_create2(const char *filename, int64_t total_size,
2070 const char *backing_file, const char *backing_format,
2071 int flags, size_t cluster_size, PreallocMode prealloc,
2072 QemuOpts *opts, int version, int refcount_order,
2073 Error **errp)
2074 {
2075 int cluster_bits;
2076 QDict *options;
2077
2078 /* Calculate cluster_bits */
2079 cluster_bits = ctz32(cluster_size);
2080 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
2081 (1 << cluster_bits) != cluster_size)
2082 {
2083 error_setg(errp, "Cluster size must be a power of two between %d and "
2084 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
2085 return -EINVAL;
2086 }
2087
2088 /*
2089 * Open the image file and write a minimal qcow2 header.
2090 *
2091 * We keep things simple and start with a zero-sized image. We also
2092 * do without refcount blocks or a L1 table for now. We'll fix the
2093 * inconsistency later.
2094 *
2095 * We do need a refcount table because growing the refcount table means
2096 * allocating two new refcount blocks - the seconds of which would be at
2097 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
2098 * size for any qcow2 image.
2099 */
2100 BlockDriverState* bs;
2101 QCowHeader *header;
2102 uint64_t* refcount_table;
2103 Error *local_err = NULL;
2104 int ret;
2105
2106 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
2107 /* Note: The following calculation does not need to be exact; if it is a
2108 * bit off, either some bytes will be "leaked" (which is fine) or we
2109 * will need to increase the file size by some bytes (which is fine,
2110 * too, as long as the bulk is allocated here). Therefore, using
2111 * floating point arithmetic is fine. */
2112 int64_t meta_size = 0;
2113 uint64_t nreftablee, nrefblocke, nl1e, nl2e;
2114 int64_t aligned_total_size = align_offset(total_size, cluster_size);
2115 int refblock_bits, refblock_size;
2116 /* refcount entry size in bytes */
2117 double rces = (1 << refcount_order) / 8.;
2118
2119 /* see qcow2_open() */
2120 refblock_bits = cluster_bits - (refcount_order - 3);
2121 refblock_size = 1 << refblock_bits;
2122
2123 /* header: 1 cluster */
2124 meta_size += cluster_size;
2125
2126 /* total size of L2 tables */
2127 nl2e = aligned_total_size / cluster_size;
2128 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
2129 meta_size += nl2e * sizeof(uint64_t);
2130
2131 /* total size of L1 tables */
2132 nl1e = nl2e * sizeof(uint64_t) / cluster_size;
2133 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t));
2134 meta_size += nl1e * sizeof(uint64_t);
2135
2136 /* total size of refcount blocks
2137 *
2138 * note: every host cluster is reference-counted, including metadata
2139 * (even refcount blocks are recursively included).
2140 * Let:
2141 * a = total_size (this is the guest disk size)
2142 * m = meta size not including refcount blocks and refcount tables
2143 * c = cluster size
2144 * y1 = number of refcount blocks entries
2145 * y2 = meta size including everything
2146 * rces = refcount entry size in bytes
2147 * then,
2148 * y1 = (y2 + a)/c
2149 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m
2150 * we can get y1:
2151 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c)
2152 */
2153 nrefblocke = (aligned_total_size + meta_size + cluster_size)
2154 / (cluster_size - rces - rces * sizeof(uint64_t)
2155 / cluster_size);
2156 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size;
2157
2158 /* total size of refcount tables */
2159 nreftablee = nrefblocke / refblock_size;
2160 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t));
2161 meta_size += nreftablee * sizeof(uint64_t);
2162
2163 qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
2164 aligned_total_size + meta_size, &error_abort);
2165 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc],
2166 &error_abort);
2167 }
2168
2169 ret = bdrv_create_file(filename, opts, &local_err);
2170 if (ret < 0) {
2171 error_propagate(errp, local_err);
2172 return ret;
2173 }
2174
2175 bs = NULL;
2176 ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
2177 &local_err);
2178 if (ret < 0) {
2179 error_propagate(errp, local_err);
2180 return ret;
2181 }
2182
2183 /* Write the header */
2184 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
2185 header = g_malloc0(cluster_size);
2186 *header = (QCowHeader) {
2187 .magic = cpu_to_be32(QCOW_MAGIC),
2188 .version = cpu_to_be32(version),
2189 .cluster_bits = cpu_to_be32(cluster_bits),
2190 .size = cpu_to_be64(0),
2191 .l1_table_offset = cpu_to_be64(0),
2192 .l1_size = cpu_to_be32(0),
2193 .refcount_table_offset = cpu_to_be64(cluster_size),
2194 .refcount_table_clusters = cpu_to_be32(1),
2195 .refcount_order = cpu_to_be32(refcount_order),
2196 .header_length = cpu_to_be32(sizeof(*header)),
2197 };
2198
2199 if (flags & BLOCK_FLAG_ENCRYPT) {
2200 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
2201 } else {
2202 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
2203 }
2204
2205 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) {
2206 header->compatible_features |=
2207 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
2208 }
2209
2210 ret = bdrv_pwrite(bs, 0, header, cluster_size);
2211 g_free(header);
2212 if (ret < 0) {
2213 error_setg_errno(errp, -ret, "Could not write qcow2 header");
2214 goto out;
2215 }
2216
2217 /* Write a refcount table with one refcount block */
2218 refcount_table = g_malloc0(2 * cluster_size);
2219 refcount_table[0] = cpu_to_be64(2 * cluster_size);
2220 ret = bdrv_pwrite(bs, cluster_size, refcount_table, 2 * cluster_size);
2221 g_free(refcount_table);
2222
2223 if (ret < 0) {
2224 error_setg_errno(errp, -ret, "Could not write refcount table");
2225 goto out;
2226 }
2227
2228 bdrv_unref(bs);
2229 bs = NULL;
2230
2231 /*
2232 * And now open the image and make it consistent first (i.e. increase the
2233 * refcount of the cluster that is occupied by the header and the refcount
2234 * table)
2235 */
2236 options = qdict_new();
2237 qdict_put(options, "driver", qstring_from_str("qcow2"));
2238 ret = bdrv_open(&bs, filename, NULL, options,
2239 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH,
2240 &local_err);
2241 if (ret < 0) {
2242 error_propagate(errp, local_err);
2243 goto out;
2244 }
2245
2246 ret = qcow2_alloc_clusters(bs, 3 * cluster_size);
2247 if (ret < 0) {
2248 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
2249 "header and refcount table");
2250 goto out;
2251
2252 } else if (ret != 0) {
2253 error_report("Huh, first cluster in empty image is already in use?");
2254 abort();
2255 }
2256
2257 /* Create a full header (including things like feature table) */
2258 ret = qcow2_update_header(bs);
2259 if (ret < 0) {
2260 error_setg_errno(errp, -ret, "Could not update qcow2 header");
2261 goto out;
2262 }
2263
2264 /* Okay, now that we have a valid image, let's give it the right size */
2265 ret = bdrv_truncate(bs, total_size);
2266 if (ret < 0) {
2267 error_setg_errno(errp, -ret, "Could not resize image");
2268 goto out;
2269 }
2270
2271 /* Want a backing file? There you go.*/
2272 if (backing_file) {
2273 ret = bdrv_change_backing_file(bs, backing_file, backing_format);
2274 if (ret < 0) {
2275 error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
2276 "with format '%s'", backing_file, backing_format);
2277 goto out;
2278 }
2279 }
2280
2281 /* And if we're supposed to preallocate metadata, do that now */
2282 if (prealloc != PREALLOC_MODE_OFF) {
2283 BDRVQcow2State *s = bs->opaque;
2284 qemu_co_mutex_lock(&s->lock);
2285 ret = preallocate(bs);
2286 qemu_co_mutex_unlock(&s->lock);
2287 if (ret < 0) {
2288 error_setg_errno(errp, -ret, "Could not preallocate metadata");
2289 goto out;
2290 }
2291 }
2292
2293 bdrv_unref(bs);
2294 bs = NULL;
2295
2296 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
2297 options = qdict_new();
2298 qdict_put(options, "driver", qstring_from_str("qcow2"));
2299 ret = bdrv_open(&bs, filename, NULL, options,
2300 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING,
2301 &local_err);
2302 if (local_err) {
2303 error_propagate(errp, local_err);
2304 goto out;
2305 }
2306
2307 ret = 0;
2308 out:
2309 if (bs) {
2310 bdrv_unref(bs);
2311 }
2312 return ret;
2313 }
2314
2315 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
2316 {
2317 char *backing_file = NULL;
2318 char *backing_fmt = NULL;
2319 char *buf = NULL;
2320 uint64_t size = 0;
2321 int flags = 0;
2322 size_t cluster_size = DEFAULT_CLUSTER_SIZE;
2323 PreallocMode prealloc;
2324 int version = 3;
2325 uint64_t refcount_bits = 16;
2326 int refcount_order;
2327 Error *local_err = NULL;
2328 int ret;
2329
2330 /* Read out options */
2331 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
2332 BDRV_SECTOR_SIZE);
2333 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
2334 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
2335 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
2336 flags |= BLOCK_FLAG_ENCRYPT;
2337 }
2338 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
2339 DEFAULT_CLUSTER_SIZE);
2340 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
2341 prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
2342 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF,
2343 &local_err);
2344 if (local_err) {
2345 error_propagate(errp, local_err);
2346 ret = -EINVAL;
2347 goto finish;
2348 }
2349 g_free(buf);
2350 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
2351 if (!buf) {
2352 /* keep the default */
2353 } else if (!strcmp(buf, "0.10")) {
2354 version = 2;
2355 } else if (!strcmp(buf, "1.1")) {
2356 version = 3;
2357 } else {
2358 error_setg(errp, "Invalid compatibility level: '%s'", buf);
2359 ret = -EINVAL;
2360 goto finish;
2361 }
2362
2363 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) {
2364 flags |= BLOCK_FLAG_LAZY_REFCOUNTS;
2365 }
2366
2367 if (backing_file && prealloc != PREALLOC_MODE_OFF) {
2368 error_setg(errp, "Backing file and preallocation cannot be used at "
2369 "the same time");
2370 ret = -EINVAL;
2371 goto finish;
2372 }
2373
2374 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) {
2375 error_setg(errp, "Lazy refcounts only supported with compatibility "
2376 "level 1.1 and above (use compat=1.1 or greater)");
2377 ret = -EINVAL;
2378 goto finish;
2379 }
2380
2381 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS,
2382 refcount_bits);
2383 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
2384 error_setg(errp, "Refcount width must be a power of two and may not "
2385 "exceed 64 bits");
2386 ret = -EINVAL;
2387 goto finish;
2388 }
2389
2390 if (version < 3 && refcount_bits != 16) {
2391 error_setg(errp, "Different refcount widths than 16 bits require "
2392 "compatibility level 1.1 or above (use compat=1.1 or "
2393 "greater)");
2394 ret = -EINVAL;
2395 goto finish;
2396 }
2397
2398 refcount_order = ctz32(refcount_bits);
2399
2400 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags,
2401 cluster_size, prealloc, opts, version, refcount_order,
2402 &local_err);
2403 if (local_err) {
2404 error_propagate(errp, local_err);
2405 }
2406
2407 finish:
2408 g_free(backing_file);
2409 g_free(backing_fmt);
2410 g_free(buf);
2411 return ret;
2412 }
2413
2414 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs,
2415 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
2416 {
2417 int ret;
2418 BDRVQcow2State *s = bs->opaque;
2419
2420 /* Emulate misaligned zero writes */
2421 if (sector_num % s->cluster_sectors || nb_sectors % s->cluster_sectors) {
2422 return -ENOTSUP;
2423 }
2424
2425 /* Whatever is left can use real zero clusters */
2426 qemu_co_mutex_lock(&s->lock);
2427 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS,
2428 nb_sectors);
2429 qemu_co_mutex_unlock(&s->lock);
2430
2431 return ret;
2432 }
2433
2434 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs,
2435 int64_t sector_num, int nb_sectors)
2436 {
2437 int ret;
2438 BDRVQcow2State *s = bs->opaque;
2439
2440 qemu_co_mutex_lock(&s->lock);
2441 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS,
2442 nb_sectors, QCOW2_DISCARD_REQUEST, false);
2443 qemu_co_mutex_unlock(&s->lock);
2444 return ret;
2445 }
2446
2447 static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
2448 {
2449 BDRVQcow2State *s = bs->opaque;
2450 int64_t new_l1_size;
2451 int ret;
2452
2453 if (offset & 511) {
2454 error_report("The new size must be a multiple of 512");
2455 return -EINVAL;
2456 }
2457
2458 /* cannot proceed if image has snapshots */
2459 if (s->nb_snapshots) {
2460 error_report("Can't resize an image which has snapshots");
2461 return -ENOTSUP;
2462 }
2463
2464 /* shrinking is currently not supported */
2465 if (offset < bs->total_sectors * 512) {
2466 error_report("qcow2 doesn't support shrinking images yet");
2467 return -ENOTSUP;
2468 }
2469
2470 new_l1_size = size_to_l1(s, offset);
2471 ret = qcow2_grow_l1_table(bs, new_l1_size, true);
2472 if (ret < 0) {
2473 return ret;
2474 }
2475
2476 /* write updated header.size */
2477 offset = cpu_to_be64(offset);
2478 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size),
2479 &offset, sizeof(uint64_t));
2480 if (ret < 0) {
2481 return ret;
2482 }
2483
2484 s->l1_vm_state_index = new_l1_size;
2485 return 0;
2486 }
2487
2488 /* XXX: put compressed sectors first, then all the cluster aligned
2489 tables to avoid losing bytes in alignment */
2490 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
2491 const uint8_t *buf, int nb_sectors)
2492 {
2493 BDRVQcow2State *s = bs->opaque;
2494 z_stream strm;
2495 int ret, out_len;
2496 uint8_t *out_buf;
2497 uint64_t cluster_offset;
2498
2499 if (nb_sectors == 0) {
2500 /* align end of file to a sector boundary to ease reading with
2501 sector based I/Os */
2502 cluster_offset = bdrv_getlength(bs->file->bs);
2503 return bdrv_truncate(bs->file->bs, cluster_offset);
2504 }
2505
2506 if (nb_sectors != s->cluster_sectors) {
2507 ret = -EINVAL;
2508
2509 /* Zero-pad last write if image size is not cluster aligned */
2510 if (sector_num + nb_sectors == bs->total_sectors &&
2511 nb_sectors < s->cluster_sectors) {
2512 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
2513 memset(pad_buf, 0, s->cluster_size);
2514 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
2515 ret = qcow2_write_compressed(bs, sector_num,
2516 pad_buf, s->cluster_sectors);
2517 qemu_vfree(pad_buf);
2518 }
2519 return ret;
2520 }
2521
2522 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
2523
2524 /* best compression, small window, no zlib header */
2525 memset(&strm, 0, sizeof(strm));
2526 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
2527 Z_DEFLATED, -12,
2528 9, Z_DEFAULT_STRATEGY);
2529 if (ret != 0) {
2530 ret = -EINVAL;
2531 goto fail;
2532 }
2533
2534 strm.avail_in = s->cluster_size;
2535 strm.next_in = (uint8_t *)buf;
2536 strm.avail_out = s->cluster_size;
2537 strm.next_out = out_buf;
2538
2539 ret = deflate(&strm, Z_FINISH);
2540 if (ret != Z_STREAM_END && ret != Z_OK) {
2541 deflateEnd(&strm);
2542 ret = -EINVAL;
2543 goto fail;
2544 }
2545 out_len = strm.next_out - out_buf;
2546
2547 deflateEnd(&strm);
2548
2549 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
2550 /* could not compress: write normal cluster */
2551 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
2552 if (ret < 0) {
2553 goto fail;
2554 }
2555 } else {
2556 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
2557 sector_num << 9, out_len);
2558 if (!cluster_offset) {
2559 ret = -EIO;
2560 goto fail;
2561 }
2562 cluster_offset &= s->cluster_offset_mask;
2563
2564 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
2565 if (ret < 0) {
2566 goto fail;
2567 }
2568
2569 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
2570 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len);
2571 if (ret < 0) {
2572 goto fail;
2573 }
2574 }
2575
2576 ret = 0;
2577 fail:
2578 g_free(out_buf);
2579 return ret;
2580 }
2581
2582 static int make_completely_empty(BlockDriverState *bs)
2583 {
2584 BDRVQcow2State *s = bs->opaque;
2585 int ret, l1_clusters;
2586 int64_t offset;
2587 uint64_t *new_reftable = NULL;
2588 uint64_t rt_entry, l1_size2;
2589 struct {
2590 uint64_t l1_offset;
2591 uint64_t reftable_offset;
2592 uint32_t reftable_clusters;
2593 } QEMU_PACKED l1_ofs_rt_ofs_cls;
2594
2595 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2596 if (ret < 0) {
2597 goto fail;
2598 }
2599
2600 ret = qcow2_cache_empty(bs, s->refcount_block_cache);
2601 if (ret < 0) {
2602 goto fail;
2603 }
2604
2605 /* Refcounts will be broken utterly */
2606 ret = qcow2_mark_dirty(bs);
2607 if (ret < 0) {
2608 goto fail;
2609 }
2610
2611 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2612
2613 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2614 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t);
2615
2616 /* After this call, neither the in-memory nor the on-disk refcount
2617 * information accurately describe the actual references */
2618
2619 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE,
2620 l1_clusters * s->cluster_sectors, 0);
2621 if (ret < 0) {
2622 goto fail_broken_refcounts;
2623 }
2624 memset(s->l1_table, 0, l1_size2);
2625
2626 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
2627
2628 /* Overwrite enough clusters at the beginning of the sectors to place
2629 * the refcount table, a refcount block and the L1 table in; this may
2630 * overwrite parts of the existing refcount and L1 table, which is not
2631 * an issue because the dirty flag is set, complete data loss is in fact
2632 * desired and partial data loss is consequently fine as well */
2633 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE,
2634 (2 + l1_clusters) * s->cluster_size /
2635 BDRV_SECTOR_SIZE, 0);
2636 /* This call (even if it failed overall) may have overwritten on-disk
2637 * refcount structures; in that case, the in-memory refcount information
2638 * will probably differ from the on-disk information which makes the BDS
2639 * unusable */
2640 if (ret < 0) {
2641 goto fail_broken_refcounts;
2642 }
2643
2644 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2645 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
2646
2647 /* "Create" an empty reftable (one cluster) directly after the image
2648 * header and an empty L1 table three clusters after the image header;
2649 * the cluster between those two will be used as the first refblock */
2650 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size);
2651 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size);
2652 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1);
2653 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset),
2654 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
2655 if (ret < 0) {
2656 goto fail_broken_refcounts;
2657 }
2658
2659 s->l1_table_offset = 3 * s->cluster_size;
2660
2661 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t));
2662 if (!new_reftable) {
2663 ret = -ENOMEM;
2664 goto fail_broken_refcounts;
2665 }
2666
2667 s->refcount_table_offset = s->cluster_size;
2668 s->refcount_table_size = s->cluster_size / sizeof(uint64_t);
2669
2670 g_free(s->refcount_table);
2671 s->refcount_table = new_reftable;
2672 new_reftable = NULL;
2673
2674 /* Now the in-memory refcount information again corresponds to the on-disk
2675 * information (reftable is empty and no refblocks (the refblock cache is
2676 * empty)); however, this means some clusters (e.g. the image header) are
2677 * referenced, but not refcounted, but the normal qcow2 code assumes that
2678 * the in-memory information is always correct */
2679
2680 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
2681
2682 /* Enter the first refblock into the reftable */
2683 rt_entry = cpu_to_be64(2 * s->cluster_size);
2684 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size,
2685 &rt_entry, sizeof(rt_entry));
2686 if (ret < 0) {
2687 goto fail_broken_refcounts;
2688 }
2689 s->refcount_table[0] = 2 * s->cluster_size;
2690
2691 s->free_cluster_index = 0;
2692 assert(3 + l1_clusters <= s->refcount_block_size);
2693 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
2694 if (offset < 0) {
2695 ret = offset;
2696 goto fail_broken_refcounts;
2697 } else if (offset > 0) {
2698 error_report("First cluster in emptied image is in use");
2699 abort();
2700 }
2701
2702 /* Now finally the in-memory information corresponds to the on-disk
2703 * structures and is correct */
2704 ret = qcow2_mark_clean(bs);
2705 if (ret < 0) {
2706 goto fail;
2707 }
2708
2709 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size);
2710 if (ret < 0) {
2711 goto fail;
2712 }
2713
2714 return 0;
2715
2716 fail_broken_refcounts:
2717 /* The BDS is unusable at this point. If we wanted to make it usable, we
2718 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
2719 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
2720 * again. However, because the functions which could have caused this error
2721 * path to be taken are used by those functions as well, it's very likely
2722 * that that sequence will fail as well. Therefore, just eject the BDS. */
2723 bs->drv = NULL;
2724
2725 fail:
2726 g_free(new_reftable);
2727 return ret;
2728 }
2729
2730 static int qcow2_make_empty(BlockDriverState *bs)
2731 {
2732 BDRVQcow2State *s = bs->opaque;
2733 uint64_t start_sector;
2734 int sector_step = INT_MAX / BDRV_SECTOR_SIZE;
2735 int l1_clusters, ret = 0;
2736
2737 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2738
2739 if (s->qcow_version >= 3 && !s->snapshots &&
2740 3 + l1_clusters <= s->refcount_block_size) {
2741 /* The following function only works for qcow2 v3 images (it requires
2742 * the dirty flag) and only as long as there are no snapshots (because
2743 * it completely empties the image). Furthermore, the L1 table and three
2744 * additional clusters (image header, refcount table, one refcount
2745 * block) have to fit inside one refcount block. */
2746 return make_completely_empty(bs);
2747 }
2748
2749 /* This fallback code simply discards every active cluster; this is slow,
2750 * but works in all cases */
2751 for (start_sector = 0; start_sector < bs->total_sectors;
2752 start_sector += sector_step)
2753 {
2754 /* As this function is generally used after committing an external
2755 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
2756 * default action for this kind of discard is to pass the discard,
2757 * which will ideally result in an actually smaller image file, as
2758 * is probably desired. */
2759 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE,
2760 MIN(sector_step,
2761 bs->total_sectors - start_sector),
2762 QCOW2_DISCARD_SNAPSHOT, true);
2763 if (ret < 0) {
2764 break;
2765 }
2766 }
2767
2768 return ret;
2769 }
2770
2771 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
2772 {
2773 BDRVQcow2State *s = bs->opaque;
2774 int ret;
2775
2776 qemu_co_mutex_lock(&s->lock);
2777 ret = qcow2_cache_flush(bs, s->l2_table_cache);
2778 if (ret < 0) {
2779 qemu_co_mutex_unlock(&s->lock);
2780 return ret;
2781 }
2782
2783 if (qcow2_need_accurate_refcounts(s)) {
2784 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
2785 if (ret < 0) {
2786 qemu_co_mutex_unlock(&s->lock);
2787 return ret;
2788 }
2789 }
2790 qemu_co_mutex_unlock(&s->lock);
2791
2792 return 0;
2793 }
2794
2795 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2796 {
2797 BDRVQcow2State *s = bs->opaque;
2798 bdi->unallocated_blocks_are_zero = true;
2799 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
2800 bdi->cluster_size = s->cluster_size;
2801 bdi->vm_state_offset = qcow2_vm_state_offset(s);
2802 return 0;
2803 }
2804
2805 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
2806 {
2807 BDRVQcow2State *s = bs->opaque;
2808 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1);
2809
2810 *spec_info = (ImageInfoSpecific){
2811 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
2812 .u.qcow2 = g_new(ImageInfoSpecificQCow2, 1),
2813 };
2814 if (s->qcow_version == 2) {
2815 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){
2816 .compat = g_strdup("0.10"),
2817 .refcount_bits = s->refcount_bits,
2818 };
2819 } else if (s->qcow_version == 3) {
2820 *spec_info->u.qcow2 = (ImageInfoSpecificQCow2){
2821 .compat = g_strdup("1.1"),
2822 .lazy_refcounts = s->compatible_features &
2823 QCOW2_COMPAT_LAZY_REFCOUNTS,
2824 .has_lazy_refcounts = true,
2825 .corrupt = s->incompatible_features &
2826 QCOW2_INCOMPAT_CORRUPT,
2827 .has_corrupt = true,
2828 .refcount_bits = s->refcount_bits,
2829 };
2830 } else {
2831 /* if this assertion fails, this probably means a new version was
2832 * added without having it covered here */
2833 assert(false);
2834 }
2835
2836 return spec_info;
2837 }
2838
2839 #if 0
2840 static void dump_refcounts(BlockDriverState *bs)
2841 {
2842 BDRVQcow2State *s = bs->opaque;
2843 int64_t nb_clusters, k, k1, size;
2844 int refcount;
2845
2846 size = bdrv_getlength(bs->file->bs);
2847 nb_clusters = size_to_clusters(s, size);
2848 for(k = 0; k < nb_clusters;) {
2849 k1 = k;
2850 refcount = get_refcount(bs, k);
2851 k++;
2852 while (k < nb_clusters && get_refcount(bs, k) == refcount)
2853 k++;
2854 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
2855 k - k1);
2856 }
2857 }
2858 #endif
2859
2860 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
2861 int64_t pos)
2862 {
2863 BDRVQcow2State *s = bs->opaque;
2864 int64_t total_sectors = bs->total_sectors;
2865 bool zero_beyond_eof = bs->zero_beyond_eof;
2866 int ret;
2867
2868 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
2869 bs->zero_beyond_eof = false;
2870 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
2871 bs->zero_beyond_eof = zero_beyond_eof;
2872
2873 /* bdrv_co_do_writev will have increased the total_sectors value to include
2874 * the VM state - the VM state is however not an actual part of the block
2875 * device, therefore, we need to restore the old value. */
2876 bs->total_sectors = total_sectors;
2877
2878 return ret;
2879 }
2880
2881 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
2882 int64_t pos, int size)
2883 {
2884 BDRVQcow2State *s = bs->opaque;
2885 bool zero_beyond_eof = bs->zero_beyond_eof;
2886 int ret;
2887
2888 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
2889 bs->zero_beyond_eof = false;
2890 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
2891 bs->zero_beyond_eof = zero_beyond_eof;
2892
2893 return ret;
2894 }
2895
2896 /*
2897 * Downgrades an image's version. To achieve this, any incompatible features
2898 * have to be removed.
2899 */
2900 static int qcow2_downgrade(BlockDriverState *bs, int target_version,
2901 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
2902 {
2903 BDRVQcow2State *s = bs->opaque;
2904 int current_version = s->qcow_version;
2905 int ret;
2906
2907 if (target_version == current_version) {
2908 return 0;
2909 } else if (target_version > current_version) {
2910 return -EINVAL;
2911 } else if (target_version != 2) {
2912 return -EINVAL;
2913 }
2914
2915 if (s->refcount_order != 4) {
2916 error_report("compat=0.10 requires refcount_bits=16");
2917 return -ENOTSUP;
2918 }
2919
2920 /* clear incompatible features */
2921 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
2922 ret = qcow2_mark_clean(bs);
2923 if (ret < 0) {
2924 return ret;
2925 }
2926 }
2927
2928 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
2929 * the first place; if that happens nonetheless, returning -ENOTSUP is the
2930 * best thing to do anyway */
2931
2932 if (s->incompatible_features) {
2933 return -ENOTSUP;
2934 }
2935
2936 /* since we can ignore compatible features, we can set them to 0 as well */
2937 s->compatible_features = 0;
2938 /* if lazy refcounts have been used, they have already been fixed through
2939 * clearing the dirty flag */
2940
2941 /* clearing autoclear features is trivial */
2942 s->autoclear_features = 0;
2943
2944 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
2945 if (ret < 0) {
2946 return ret;
2947 }
2948
2949 s->qcow_version = target_version;
2950 ret = qcow2_update_header(bs);
2951 if (ret < 0) {
2952 s->qcow_version = current_version;
2953 return ret;
2954 }
2955 return 0;
2956 }
2957
2958 typedef enum Qcow2AmendOperation {
2959 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
2960 * statically initialized to so that the helper CB can discern the first
2961 * invocation from an operation change */
2962 QCOW2_NO_OPERATION = 0,
2963
2964 QCOW2_CHANGING_REFCOUNT_ORDER,
2965 QCOW2_DOWNGRADING,
2966 } Qcow2AmendOperation;
2967
2968 typedef struct Qcow2AmendHelperCBInfo {
2969 /* The code coordinating the amend operations should only modify
2970 * these four fields; the rest will be managed by the CB */
2971 BlockDriverAmendStatusCB *original_status_cb;
2972 void *original_cb_opaque;
2973
2974 Qcow2AmendOperation current_operation;
2975
2976 /* Total number of operations to perform (only set once) */
2977 int total_operations;
2978
2979 /* The following fields are managed by the CB */
2980
2981 /* Number of operations completed */
2982 int operations_completed;
2983
2984 /* Cumulative offset of all completed operations */
2985 int64_t offset_completed;
2986
2987 Qcow2AmendOperation last_operation;
2988 int64_t last_work_size;
2989 } Qcow2AmendHelperCBInfo;
2990
2991 static void qcow2_amend_helper_cb(BlockDriverState *bs,
2992 int64_t operation_offset,
2993 int64_t operation_work_size, void *opaque)
2994 {
2995 Qcow2AmendHelperCBInfo *info = opaque;
2996 int64_t current_work_size;
2997 int64_t projected_work_size;
2998
2999 if (info->current_operation != info->last_operation) {
3000 if (info->last_operation != QCOW2_NO_OPERATION) {
3001 info->offset_completed += info->last_work_size;
3002 info->operations_completed++;
3003 }
3004
3005 info->last_operation = info->current_operation;
3006 }
3007
3008 assert(info->total_operations > 0);
3009 assert(info->operations_completed < info->total_operations);
3010
3011 info->last_work_size = operation_work_size;
3012
3013 current_work_size = info->offset_completed + operation_work_size;
3014
3015 /* current_work_size is the total work size for (operations_completed + 1)
3016 * operations (which includes this one), so multiply it by the number of
3017 * operations not covered and divide it by the number of operations
3018 * covered to get a projection for the operations not covered */
3019 projected_work_size = current_work_size * (info->total_operations -
3020 info->operations_completed - 1)
3021 / (info->operations_completed + 1);
3022
3023 info->original_status_cb(bs, info->offset_completed + operation_offset,
3024 current_work_size + projected_work_size,
3025 info->original_cb_opaque);
3026 }
3027
3028 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
3029 BlockDriverAmendStatusCB *status_cb,
3030 void *cb_opaque)
3031 {
3032 BDRVQcow2State *s = bs->opaque;
3033 int old_version = s->qcow_version, new_version = old_version;
3034 uint64_t new_size = 0;
3035 const char *backing_file = NULL, *backing_format = NULL;
3036 bool lazy_refcounts = s->use_lazy_refcounts;
3037 const char *compat = NULL;
3038 uint64_t cluster_size = s->cluster_size;
3039 bool encrypt;
3040 int refcount_bits = s->refcount_bits;
3041 int ret;
3042 QemuOptDesc *desc = opts->list->desc;
3043 Qcow2AmendHelperCBInfo helper_cb_info;
3044
3045 while (desc && desc->name) {
3046 if (!qemu_opt_find(opts, desc->name)) {
3047 /* only change explicitly defined options */
3048 desc++;
3049 continue;
3050 }
3051
3052 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
3053 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
3054 if (!compat) {
3055 /* preserve default */
3056 } else if (!strcmp(compat, "0.10")) {
3057 new_version = 2;
3058 } else if (!strcmp(compat, "1.1")) {
3059 new_version = 3;
3060 } else {
3061 error_report("Unknown compatibility level %s", compat);
3062 return -EINVAL;
3063 }
3064 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) {
3065 error_report("Cannot change preallocation mode");
3066 return -ENOTSUP;
3067 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
3068 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3069 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
3070 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3071 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
3072 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3073 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
3074 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
3075 !!s->cipher);
3076
3077 if (encrypt != !!s->cipher) {
3078 error_report("Changing the encryption flag is not supported");
3079 return -ENOTSUP;
3080 }
3081 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
3082 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
3083 cluster_size);
3084 if (cluster_size != s->cluster_size) {
3085 error_report("Changing the cluster size is not supported");
3086 return -ENOTSUP;
3087 }
3088 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
3089 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
3090 lazy_refcounts);
3091 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
3092 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS,
3093 refcount_bits);
3094
3095 if (refcount_bits <= 0 || refcount_bits > 64 ||
3096 !is_power_of_2(refcount_bits))
3097 {
3098 error_report("Refcount width must be a power of two and may "
3099 "not exceed 64 bits");
3100 return -EINVAL;
3101 }
3102 } else {
3103 /* if this point is reached, this probably means a new option was
3104 * added without having it covered here */
3105 abort();
3106 }
3107
3108 desc++;
3109 }
3110
3111 helper_cb_info = (Qcow2AmendHelperCBInfo){
3112 .original_status_cb = status_cb,
3113 .original_cb_opaque = cb_opaque,
3114 .total_operations = (new_version < old_version)
3115 + (s->refcount_bits != refcount_bits)
3116 };
3117
3118 /* Upgrade first (some features may require compat=1.1) */
3119 if (new_version > old_version) {
3120 s->qcow_version = new_version;
3121 ret = qcow2_update_header(bs);
3122 if (ret < 0) {
3123 s->qcow_version = old_version;
3124 return ret;
3125 }
3126 }
3127
3128 if (s->refcount_bits != refcount_bits) {
3129 int refcount_order = ctz32(refcount_bits);
3130 Error *local_error = NULL;
3131
3132 if (new_version < 3 && refcount_bits != 16) {
3133 error_report("Different refcount widths than 16 bits require "
3134 "compatibility level 1.1 or above (use compat=1.1 or "
3135 "greater)");
3136 return -EINVAL;
3137 }
3138
3139 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER;
3140 ret = qcow2_change_refcount_order(bs, refcount_order,
3141 &qcow2_amend_helper_cb,
3142 &helper_cb_info, &local_error);
3143 if (ret < 0) {
3144 error_report_err(local_error);
3145 return ret;
3146 }
3147 }
3148
3149 if (backing_file || backing_format) {
3150 ret = qcow2_change_backing_file(bs,
3151 backing_file ?: s->image_backing_file,
3152 backing_format ?: s->image_backing_format);
3153 if (ret < 0) {
3154 return ret;
3155 }
3156 }
3157
3158 if (s->use_lazy_refcounts != lazy_refcounts) {
3159 if (lazy_refcounts) {
3160 if (new_version < 3) {
3161 error_report("Lazy refcounts only supported with compatibility "
3162 "level 1.1 and above (use compat=1.1 or greater)");
3163 return -EINVAL;
3164 }
3165 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3166 ret = qcow2_update_header(bs);
3167 if (ret < 0) {
3168 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3169 return ret;
3170 }
3171 s->use_lazy_refcounts = true;
3172 } else {
3173 /* make image clean first */
3174 ret = qcow2_mark_clean(bs);
3175 if (ret < 0) {
3176 return ret;
3177 }
3178 /* now disallow lazy refcounts */
3179 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3180 ret = qcow2_update_header(bs);
3181 if (ret < 0) {
3182 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3183 return ret;
3184 }
3185 s->use_lazy_refcounts = false;
3186 }
3187 }
3188
3189 if (new_size) {
3190 ret = bdrv_truncate(bs, new_size);
3191 if (ret < 0) {
3192 return ret;
3193 }
3194 }
3195
3196 /* Downgrade last (so unsupported features can be removed before) */
3197 if (new_version < old_version) {
3198 helper_cb_info.current_operation = QCOW2_DOWNGRADING;
3199 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb,
3200 &helper_cb_info);
3201 if (ret < 0) {
3202 return ret;
3203 }
3204 }
3205
3206 return 0;
3207 }
3208
3209 /*
3210 * If offset or size are negative, respectively, they will not be included in
3211 * the BLOCK_IMAGE_CORRUPTED event emitted.
3212 * fatal will be ignored for read-only BDS; corruptions found there will always
3213 * be considered non-fatal.
3214 */
3215 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
3216 int64_t size, const char *message_format, ...)
3217 {
3218 BDRVQcow2State *s = bs->opaque;
3219 const char *node_name;
3220 char *message;
3221 va_list ap;
3222
3223 fatal = fatal && !bs->read_only;
3224
3225 if (s->signaled_corruption &&
3226 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
3227 {
3228 return;
3229 }
3230
3231 va_start(ap, message_format);
3232 message = g_strdup_vprintf(message_format, ap);
3233 va_end(ap);
3234
3235 if (fatal) {
3236 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
3237 "corruption events will be suppressed\n", message);
3238 } else {
3239 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
3240 "corruption events will be suppressed\n", message);
3241 }
3242
3243 node_name = bdrv_get_node_name(bs);
3244 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
3245 *node_name != '\0', node_name,
3246 message, offset >= 0, offset,
3247 size >= 0, size,
3248 fatal, &error_abort);
3249 g_free(message);
3250
3251 if (fatal) {
3252 qcow2_mark_corrupt(bs);
3253 bs->drv = NULL; /* make BDS unusable */
3254 }
3255
3256 s->signaled_corruption = true;
3257 }
3258
3259 static QemuOptsList qcow2_create_opts = {
3260 .name = "qcow2-create-opts",
3261 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
3262 .desc = {
3263 {
3264 .name = BLOCK_OPT_SIZE,
3265 .type = QEMU_OPT_SIZE,
3266 .help = "Virtual disk size"
3267 },
3268 {
3269 .name = BLOCK_OPT_COMPAT_LEVEL,
3270 .type = QEMU_OPT_STRING,
3271 .help = "Compatibility level (0.10 or 1.1)"
3272 },
3273 {
3274 .name = BLOCK_OPT_BACKING_FILE,
3275 .type = QEMU_OPT_STRING,
3276 .help = "File name of a base image"
3277 },
3278 {
3279 .name = BLOCK_OPT_BACKING_FMT,
3280 .type = QEMU_OPT_STRING,
3281 .help = "Image format of the base image"
3282 },
3283 {
3284 .name = BLOCK_OPT_ENCRYPT,
3285 .type = QEMU_OPT_BOOL,
3286 .help = "Encrypt the image",
3287 .def_value_str = "off"
3288 },
3289 {
3290 .name = BLOCK_OPT_CLUSTER_SIZE,
3291 .type = QEMU_OPT_SIZE,
3292 .help = "qcow2 cluster size",
3293 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
3294 },
3295 {
3296 .name = BLOCK_OPT_PREALLOC,
3297 .type = QEMU_OPT_STRING,
3298 .help = "Preallocation mode (allowed values: off, metadata, "
3299 "falloc, full)"
3300 },
3301 {
3302 .name = BLOCK_OPT_LAZY_REFCOUNTS,
3303 .type = QEMU_OPT_BOOL,
3304 .help = "Postpone refcount updates",
3305 .def_value_str = "off"
3306 },
3307 {
3308 .name = BLOCK_OPT_REFCOUNT_BITS,
3309 .type = QEMU_OPT_NUMBER,
3310 .help = "Width of a reference count entry in bits",
3311 .def_value_str = "16"
3312 },
3313 { /* end of list */ }
3314 }
3315 };
3316
3317 BlockDriver bdrv_qcow2 = {
3318 .format_name = "qcow2",
3319 .instance_size = sizeof(BDRVQcow2State),
3320 .bdrv_probe = qcow2_probe,
3321 .bdrv_open = qcow2_open,
3322 .bdrv_close = qcow2_close,
3323 .bdrv_reopen_prepare = qcow2_reopen_prepare,
3324 .bdrv_reopen_commit = qcow2_reopen_commit,
3325 .bdrv_reopen_abort = qcow2_reopen_abort,
3326 .bdrv_join_options = qcow2_join_options,
3327 .bdrv_create = qcow2_create,
3328 .bdrv_has_zero_init = bdrv_has_zero_init_1,
3329 .bdrv_co_get_block_status = qcow2_co_get_block_status,
3330 .bdrv_set_key = qcow2_set_key,
3331
3332 .bdrv_co_readv = qcow2_co_readv,
3333 .bdrv_co_writev = qcow2_co_writev,
3334 .bdrv_co_flush_to_os = qcow2_co_flush_to_os,
3335
3336 .bdrv_co_write_zeroes = qcow2_co_write_zeroes,
3337 .bdrv_co_discard = qcow2_co_discard,
3338 .bdrv_truncate = qcow2_truncate,
3339 .bdrv_write_compressed = qcow2_write_compressed,
3340 .bdrv_make_empty = qcow2_make_empty,
3341
3342 .bdrv_snapshot_create = qcow2_snapshot_create,
3343 .bdrv_snapshot_goto = qcow2_snapshot_goto,
3344 .bdrv_snapshot_delete = qcow2_snapshot_delete,
3345 .bdrv_snapshot_list = qcow2_snapshot_list,
3346 .bdrv_snapshot_load_tmp = qcow2_snapshot_load_tmp,
3347 .bdrv_get_info = qcow2_get_info,
3348 .bdrv_get_specific_info = qcow2_get_specific_info,
3349
3350 .bdrv_save_vmstate = qcow2_save_vmstate,
3351 .bdrv_load_vmstate = qcow2_load_vmstate,
3352
3353 .supports_backing = true,
3354 .bdrv_change_backing_file = qcow2_change_backing_file,
3355
3356 .bdrv_refresh_limits = qcow2_refresh_limits,
3357 .bdrv_invalidate_cache = qcow2_invalidate_cache,
3358 .bdrv_inactivate = qcow2_inactivate,
3359
3360 .create_opts = &qcow2_create_opts,
3361 .bdrv_check = qcow2_check,
3362 .bdrv_amend_options = qcow2_amend_options,
3363
3364 .bdrv_detach_aio_context = qcow2_detach_aio_context,
3365 .bdrv_attach_aio_context = qcow2_attach_aio_context,
3366 };
3367
3368 static void bdrv_qcow2_init(void)
3369 {
3370 bdrv_register(&bdrv_qcow2);
3371 }
3372
3373 block_init(bdrv_qcow2_init);
QEmu