vmxnet3: Use common MAC address tracing macros
[qemu.git] / block / qcow2.c
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 "block/block_int.h"
26 #include "sysemu/block-backend.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 #include "qemu/cutils.h"
39 #include "qemu/bswap.h"
40
41 /*
42 Differences with QCOW:
43
44 - Support for multiple incremental snapshots.
45 - Memory management by reference counts.
46 - Clusters which have a reference count of one have the bit
47 QCOW_OFLAG_COPIED to optimize write performance.
48 - Size of compressed clusters is stored in sectors to reduce bit usage
49 in the cluster offsets.
50 - Support for storing additional data (such as the VM state) in the
51 snapshots.
52 - If a backing store is used, the cluster size is not constrained
53 (could be backported to QCOW).
54 - L2 tables have always a size of one cluster.
55 */
56
57
58 typedef struct {
59 uint32_t magic;
60 uint32_t len;
61 } QEMU_PACKED QCowExtension;
62
63 #define QCOW2_EXT_MAGIC_END 0
64 #define QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
65 #define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
66
67 static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
68 {
69 const QCowHeader *cow_header = (const void *)buf;
70
71 if (buf_size >= sizeof(QCowHeader) &&
72 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
73 be32_to_cpu(cow_header->version) >= 2)
74 return 100;
75 else
76 return 0;
77 }
78
79
80 /*
81 * read qcow2 extension and fill bs
82 * start reading from start_offset
83 * finish reading upon magic of value 0 or when end_offset reached
84 * unknown magic is skipped (future extension this version knows nothing about)
85 * return 0 upon success, non-0 otherwise
86 */
87 static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
88 uint64_t end_offset, void **p_feature_table,
89 Error **errp)
90 {
91 BDRVQcow2State *s = bs->opaque;
92 QCowExtension ext;
93 uint64_t offset;
94 int ret;
95
96 #ifdef DEBUG_EXT
97 printf("qcow2_read_extensions: start=%ld end=%ld\n", start_offset, end_offset);
98 #endif
99 offset = start_offset;
100 while (offset < end_offset) {
101
102 #ifdef DEBUG_EXT
103 /* Sanity check */
104 if (offset > s->cluster_size)
105 printf("qcow2_read_extension: suspicious offset %lu\n", offset);
106
107 printf("attempting to read extended header in offset %lu\n", offset);
108 #endif
109
110 ret = bdrv_pread(bs->file->bs, offset, &ext, sizeof(ext));
111 if (ret < 0) {
112 error_setg_errno(errp, -ret, "qcow2_read_extension: ERROR: "
113 "pread fail from offset %" PRIu64, offset);
114 return 1;
115 }
116 be32_to_cpus(&ext.magic);
117 be32_to_cpus(&ext.len);
118 offset += sizeof(ext);
119 #ifdef DEBUG_EXT
120 printf("ext.magic = 0x%x\n", ext.magic);
121 #endif
122 if (offset > end_offset || ext.len > end_offset - offset) {
123 error_setg(errp, "Header extension too large");
124 return -EINVAL;
125 }
126
127 switch (ext.magic) {
128 case QCOW2_EXT_MAGIC_END:
129 return 0;
130
131 case QCOW2_EXT_MAGIC_BACKING_FORMAT:
132 if (ext.len >= sizeof(bs->backing_format)) {
133 error_setg(errp, "ERROR: ext_backing_format: len=%" PRIu32
134 " too large (>=%zu)", ext.len,
135 sizeof(bs->backing_format));
136 return 2;
137 }
138 ret = bdrv_pread(bs->file->bs, offset, bs->backing_format, ext.len);
139 if (ret < 0) {
140 error_setg_errno(errp, -ret, "ERROR: ext_backing_format: "
141 "Could not read format name");
142 return 3;
143 }
144 bs->backing_format[ext.len] = '\0';
145 s->image_backing_format = g_strdup(bs->backing_format);
146 #ifdef DEBUG_EXT
147 printf("Qcow2: Got format extension %s\n", bs->backing_format);
148 #endif
149 break;
150
151 case QCOW2_EXT_MAGIC_FEATURE_TABLE:
152 if (p_feature_table != NULL) {
153 void* feature_table = g_malloc0(ext.len + 2 * sizeof(Qcow2Feature));
154 ret = bdrv_pread(bs->file->bs, offset , feature_table, ext.len);
155 if (ret < 0) {
156 error_setg_errno(errp, -ret, "ERROR: ext_feature_table: "
157 "Could not read table");
158 return ret;
159 }
160
161 *p_feature_table = feature_table;
162 }
163 break;
164
165 default:
166 /* unknown magic - save it in case we need to rewrite the header */
167 {
168 Qcow2UnknownHeaderExtension *uext;
169
170 uext = g_malloc0(sizeof(*uext) + ext.len);
171 uext->magic = ext.magic;
172 uext->len = ext.len;
173 QLIST_INSERT_HEAD(&s->unknown_header_ext, uext, next);
174
175 ret = bdrv_pread(bs->file->bs, offset , uext->data, uext->len);
176 if (ret < 0) {
177 error_setg_errno(errp, -ret, "ERROR: unknown extension: "
178 "Could not read data");
179 return ret;
180 }
181 }
182 break;
183 }
184
185 offset += ((ext.len + 7) & ~7);
186 }
187
188 return 0;
189 }
190
191 static void cleanup_unknown_header_ext(BlockDriverState *bs)
192 {
193 BDRVQcow2State *s = bs->opaque;
194 Qcow2UnknownHeaderExtension *uext, *next;
195
196 QLIST_FOREACH_SAFE(uext, &s->unknown_header_ext, next, next) {
197 QLIST_REMOVE(uext, next);
198 g_free(uext);
199 }
200 }
201
202 static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
203 uint64_t mask)
204 {
205 char *features = g_strdup("");
206 char *old;
207
208 while (table && table->name[0] != '\0') {
209 if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
210 if (mask & (1ULL << table->bit)) {
211 old = features;
212 features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
213 table->name);
214 g_free(old);
215 mask &= ~(1ULL << table->bit);
216 }
217 }
218 table++;
219 }
220
221 if (mask) {
222 old = features;
223 features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
224 old, *old ? ", " : "", mask);
225 g_free(old);
226 }
227
228 error_setg(errp, "Unsupported qcow2 feature(s): %s", features);
229 g_free(features);
230 }
231
232 /*
233 * Sets the dirty bit and flushes afterwards if necessary.
234 *
235 * The incompatible_features bit is only set if the image file header was
236 * updated successfully. Therefore it is not required to check the return
237 * value of this function.
238 */
239 int qcow2_mark_dirty(BlockDriverState *bs)
240 {
241 BDRVQcow2State *s = bs->opaque;
242 uint64_t val;
243 int ret;
244
245 assert(s->qcow_version >= 3);
246
247 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
248 return 0; /* already dirty */
249 }
250
251 val = cpu_to_be64(s->incompatible_features | QCOW2_INCOMPAT_DIRTY);
252 ret = bdrv_pwrite(bs->file->bs, offsetof(QCowHeader, incompatible_features),
253 &val, sizeof(val));
254 if (ret < 0) {
255 return ret;
256 }
257 ret = bdrv_flush(bs->file->bs);
258 if (ret < 0) {
259 return ret;
260 }
261
262 /* Only treat image as dirty if the header was updated successfully */
263 s->incompatible_features |= QCOW2_INCOMPAT_DIRTY;
264 return 0;
265 }
266
267 /*
268 * Clears the dirty bit and flushes before if necessary. Only call this
269 * function when there are no pending requests, it does not guard against
270 * concurrent requests dirtying the image.
271 */
272 static int qcow2_mark_clean(BlockDriverState *bs)
273 {
274 BDRVQcow2State *s = bs->opaque;
275
276 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
277 int ret;
278
279 s->incompatible_features &= ~QCOW2_INCOMPAT_DIRTY;
280
281 ret = bdrv_flush(bs);
282 if (ret < 0) {
283 return ret;
284 }
285
286 return qcow2_update_header(bs);
287 }
288 return 0;
289 }
290
291 /*
292 * Marks the image as corrupt.
293 */
294 int qcow2_mark_corrupt(BlockDriverState *bs)
295 {
296 BDRVQcow2State *s = bs->opaque;
297
298 s->incompatible_features |= QCOW2_INCOMPAT_CORRUPT;
299 return qcow2_update_header(bs);
300 }
301
302 /*
303 * Marks the image as consistent, i.e., unsets the corrupt bit, and flushes
304 * before if necessary.
305 */
306 int qcow2_mark_consistent(BlockDriverState *bs)
307 {
308 BDRVQcow2State *s = bs->opaque;
309
310 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
311 int ret = bdrv_flush(bs);
312 if (ret < 0) {
313 return ret;
314 }
315
316 s->incompatible_features &= ~QCOW2_INCOMPAT_CORRUPT;
317 return qcow2_update_header(bs);
318 }
319 return 0;
320 }
321
322 static int qcow2_check(BlockDriverState *bs, BdrvCheckResult *result,
323 BdrvCheckMode fix)
324 {
325 int ret = qcow2_check_refcounts(bs, result, fix);
326 if (ret < 0) {
327 return ret;
328 }
329
330 if (fix && result->check_errors == 0 && result->corruptions == 0) {
331 ret = qcow2_mark_clean(bs);
332 if (ret < 0) {
333 return ret;
334 }
335 return qcow2_mark_consistent(bs);
336 }
337 return ret;
338 }
339
340 static int validate_table_offset(BlockDriverState *bs, uint64_t offset,
341 uint64_t entries, size_t entry_len)
342 {
343 BDRVQcow2State *s = bs->opaque;
344 uint64_t size;
345
346 /* Use signed INT64_MAX as the maximum even for uint64_t header fields,
347 * because values will be passed to qemu functions taking int64_t. */
348 if (entries > INT64_MAX / entry_len) {
349 return -EINVAL;
350 }
351
352 size = entries * entry_len;
353
354 if (INT64_MAX - size < offset) {
355 return -EINVAL;
356 }
357
358 /* Tables must be cluster aligned */
359 if (offset & (s->cluster_size - 1)) {
360 return -EINVAL;
361 }
362
363 return 0;
364 }
365
366 static QemuOptsList qcow2_runtime_opts = {
367 .name = "qcow2",
368 .head = QTAILQ_HEAD_INITIALIZER(qcow2_runtime_opts.head),
369 .desc = {
370 {
371 .name = QCOW2_OPT_LAZY_REFCOUNTS,
372 .type = QEMU_OPT_BOOL,
373 .help = "Postpone refcount updates",
374 },
375 {
376 .name = QCOW2_OPT_DISCARD_REQUEST,
377 .type = QEMU_OPT_BOOL,
378 .help = "Pass guest discard requests to the layer below",
379 },
380 {
381 .name = QCOW2_OPT_DISCARD_SNAPSHOT,
382 .type = QEMU_OPT_BOOL,
383 .help = "Generate discard requests when snapshot related space "
384 "is freed",
385 },
386 {
387 .name = QCOW2_OPT_DISCARD_OTHER,
388 .type = QEMU_OPT_BOOL,
389 .help = "Generate discard requests when other clusters are freed",
390 },
391 {
392 .name = QCOW2_OPT_OVERLAP,
393 .type = QEMU_OPT_STRING,
394 .help = "Selects which overlap checks to perform from a range of "
395 "templates (none, constant, cached, all)",
396 },
397 {
398 .name = QCOW2_OPT_OVERLAP_TEMPLATE,
399 .type = QEMU_OPT_STRING,
400 .help = "Selects which overlap checks to perform from a range of "
401 "templates (none, constant, cached, all)",
402 },
403 {
404 .name = QCOW2_OPT_OVERLAP_MAIN_HEADER,
405 .type = QEMU_OPT_BOOL,
406 .help = "Check for unintended writes into the main qcow2 header",
407 },
408 {
409 .name = QCOW2_OPT_OVERLAP_ACTIVE_L1,
410 .type = QEMU_OPT_BOOL,
411 .help = "Check for unintended writes into the active L1 table",
412 },
413 {
414 .name = QCOW2_OPT_OVERLAP_ACTIVE_L2,
415 .type = QEMU_OPT_BOOL,
416 .help = "Check for unintended writes into an active L2 table",
417 },
418 {
419 .name = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
420 .type = QEMU_OPT_BOOL,
421 .help = "Check for unintended writes into the refcount table",
422 },
423 {
424 .name = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
425 .type = QEMU_OPT_BOOL,
426 .help = "Check for unintended writes into a refcount block",
427 },
428 {
429 .name = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
430 .type = QEMU_OPT_BOOL,
431 .help = "Check for unintended writes into the snapshot table",
432 },
433 {
434 .name = QCOW2_OPT_OVERLAP_INACTIVE_L1,
435 .type = QEMU_OPT_BOOL,
436 .help = "Check for unintended writes into an inactive L1 table",
437 },
438 {
439 .name = QCOW2_OPT_OVERLAP_INACTIVE_L2,
440 .type = QEMU_OPT_BOOL,
441 .help = "Check for unintended writes into an inactive L2 table",
442 },
443 {
444 .name = QCOW2_OPT_CACHE_SIZE,
445 .type = QEMU_OPT_SIZE,
446 .help = "Maximum combined metadata (L2 tables and refcount blocks) "
447 "cache size",
448 },
449 {
450 .name = QCOW2_OPT_L2_CACHE_SIZE,
451 .type = QEMU_OPT_SIZE,
452 .help = "Maximum L2 table cache size",
453 },
454 {
455 .name = QCOW2_OPT_REFCOUNT_CACHE_SIZE,
456 .type = QEMU_OPT_SIZE,
457 .help = "Maximum refcount block cache size",
458 },
459 {
460 .name = QCOW2_OPT_CACHE_CLEAN_INTERVAL,
461 .type = QEMU_OPT_NUMBER,
462 .help = "Clean unused cache entries after this time (in seconds)",
463 },
464 { /* end of list */ }
465 },
466 };
467
468 static const char *overlap_bool_option_names[QCOW2_OL_MAX_BITNR] = {
469 [QCOW2_OL_MAIN_HEADER_BITNR] = QCOW2_OPT_OVERLAP_MAIN_HEADER,
470 [QCOW2_OL_ACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L1,
471 [QCOW2_OL_ACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_ACTIVE_L2,
472 [QCOW2_OL_REFCOUNT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_TABLE,
473 [QCOW2_OL_REFCOUNT_BLOCK_BITNR] = QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK,
474 [QCOW2_OL_SNAPSHOT_TABLE_BITNR] = QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE,
475 [QCOW2_OL_INACTIVE_L1_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L1,
476 [QCOW2_OL_INACTIVE_L2_BITNR] = QCOW2_OPT_OVERLAP_INACTIVE_L2,
477 };
478
479 static void cache_clean_timer_cb(void *opaque)
480 {
481 BlockDriverState *bs = opaque;
482 BDRVQcow2State *s = bs->opaque;
483 qcow2_cache_clean_unused(bs, s->l2_table_cache);
484 qcow2_cache_clean_unused(bs, s->refcount_block_cache);
485 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
486 (int64_t) s->cache_clean_interval * 1000);
487 }
488
489 static void cache_clean_timer_init(BlockDriverState *bs, AioContext *context)
490 {
491 BDRVQcow2State *s = bs->opaque;
492 if (s->cache_clean_interval > 0) {
493 s->cache_clean_timer = aio_timer_new(context, QEMU_CLOCK_VIRTUAL,
494 SCALE_MS, cache_clean_timer_cb,
495 bs);
496 timer_mod(s->cache_clean_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
497 (int64_t) s->cache_clean_interval * 1000);
498 }
499 }
500
501 static void cache_clean_timer_del(BlockDriverState *bs)
502 {
503 BDRVQcow2State *s = bs->opaque;
504 if (s->cache_clean_timer) {
505 timer_del(s->cache_clean_timer);
506 timer_free(s->cache_clean_timer);
507 s->cache_clean_timer = NULL;
508 }
509 }
510
511 static void qcow2_detach_aio_context(BlockDriverState *bs)
512 {
513 cache_clean_timer_del(bs);
514 }
515
516 static void qcow2_attach_aio_context(BlockDriverState *bs,
517 AioContext *new_context)
518 {
519 cache_clean_timer_init(bs, new_context);
520 }
521
522 static void read_cache_sizes(BlockDriverState *bs, QemuOpts *opts,
523 uint64_t *l2_cache_size,
524 uint64_t *refcount_cache_size, Error **errp)
525 {
526 BDRVQcow2State *s = bs->opaque;
527 uint64_t combined_cache_size;
528 bool l2_cache_size_set, refcount_cache_size_set, combined_cache_size_set;
529
530 combined_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_CACHE_SIZE);
531 l2_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_L2_CACHE_SIZE);
532 refcount_cache_size_set = qemu_opt_get(opts, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
533
534 combined_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_CACHE_SIZE, 0);
535 *l2_cache_size = qemu_opt_get_size(opts, QCOW2_OPT_L2_CACHE_SIZE, 0);
536 *refcount_cache_size = qemu_opt_get_size(opts,
537 QCOW2_OPT_REFCOUNT_CACHE_SIZE, 0);
538
539 if (combined_cache_size_set) {
540 if (l2_cache_size_set && refcount_cache_size_set) {
541 error_setg(errp, QCOW2_OPT_CACHE_SIZE ", " QCOW2_OPT_L2_CACHE_SIZE
542 " and " QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not be set "
543 "the same time");
544 return;
545 } else if (*l2_cache_size > combined_cache_size) {
546 error_setg(errp, QCOW2_OPT_L2_CACHE_SIZE " may not exceed "
547 QCOW2_OPT_CACHE_SIZE);
548 return;
549 } else if (*refcount_cache_size > combined_cache_size) {
550 error_setg(errp, QCOW2_OPT_REFCOUNT_CACHE_SIZE " may not exceed "
551 QCOW2_OPT_CACHE_SIZE);
552 return;
553 }
554
555 if (l2_cache_size_set) {
556 *refcount_cache_size = combined_cache_size - *l2_cache_size;
557 } else if (refcount_cache_size_set) {
558 *l2_cache_size = combined_cache_size - *refcount_cache_size;
559 } else {
560 *refcount_cache_size = combined_cache_size
561 / (DEFAULT_L2_REFCOUNT_SIZE_RATIO + 1);
562 *l2_cache_size = combined_cache_size - *refcount_cache_size;
563 }
564 } else {
565 if (!l2_cache_size_set && !refcount_cache_size_set) {
566 *l2_cache_size = MAX(DEFAULT_L2_CACHE_BYTE_SIZE,
567 (uint64_t)DEFAULT_L2_CACHE_CLUSTERS
568 * s->cluster_size);
569 *refcount_cache_size = *l2_cache_size
570 / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
571 } else if (!l2_cache_size_set) {
572 *l2_cache_size = *refcount_cache_size
573 * DEFAULT_L2_REFCOUNT_SIZE_RATIO;
574 } else if (!refcount_cache_size_set) {
575 *refcount_cache_size = *l2_cache_size
576 / DEFAULT_L2_REFCOUNT_SIZE_RATIO;
577 }
578 }
579 }
580
581 typedef struct Qcow2ReopenState {
582 Qcow2Cache *l2_table_cache;
583 Qcow2Cache *refcount_block_cache;
584 bool use_lazy_refcounts;
585 int overlap_check;
586 bool discard_passthrough[QCOW2_DISCARD_MAX];
587 uint64_t cache_clean_interval;
588 } Qcow2ReopenState;
589
590 static int qcow2_update_options_prepare(BlockDriverState *bs,
591 Qcow2ReopenState *r,
592 QDict *options, int flags,
593 Error **errp)
594 {
595 BDRVQcow2State *s = bs->opaque;
596 QemuOpts *opts = NULL;
597 const char *opt_overlap_check, *opt_overlap_check_template;
598 int overlap_check_template = 0;
599 uint64_t l2_cache_size, refcount_cache_size;
600 int i;
601 Error *local_err = NULL;
602 int ret;
603
604 opts = qemu_opts_create(&qcow2_runtime_opts, NULL, 0, &error_abort);
605 qemu_opts_absorb_qdict(opts, options, &local_err);
606 if (local_err) {
607 error_propagate(errp, local_err);
608 ret = -EINVAL;
609 goto fail;
610 }
611
612 /* get L2 table/refcount block cache size from command line options */
613 read_cache_sizes(bs, opts, &l2_cache_size, &refcount_cache_size,
614 &local_err);
615 if (local_err) {
616 error_propagate(errp, local_err);
617 ret = -EINVAL;
618 goto fail;
619 }
620
621 l2_cache_size /= s->cluster_size;
622 if (l2_cache_size < MIN_L2_CACHE_SIZE) {
623 l2_cache_size = MIN_L2_CACHE_SIZE;
624 }
625 if (l2_cache_size > INT_MAX) {
626 error_setg(errp, "L2 cache size too big");
627 ret = -EINVAL;
628 goto fail;
629 }
630
631 refcount_cache_size /= s->cluster_size;
632 if (refcount_cache_size < MIN_REFCOUNT_CACHE_SIZE) {
633 refcount_cache_size = MIN_REFCOUNT_CACHE_SIZE;
634 }
635 if (refcount_cache_size > INT_MAX) {
636 error_setg(errp, "Refcount cache size too big");
637 ret = -EINVAL;
638 goto fail;
639 }
640
641 /* alloc new L2 table/refcount block cache, flush old one */
642 if (s->l2_table_cache) {
643 ret = qcow2_cache_flush(bs, s->l2_table_cache);
644 if (ret) {
645 error_setg_errno(errp, -ret, "Failed to flush the L2 table cache");
646 goto fail;
647 }
648 }
649
650 if (s->refcount_block_cache) {
651 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
652 if (ret) {
653 error_setg_errno(errp, -ret,
654 "Failed to flush the refcount block cache");
655 goto fail;
656 }
657 }
658
659 r->l2_table_cache = qcow2_cache_create(bs, l2_cache_size);
660 r->refcount_block_cache = qcow2_cache_create(bs, refcount_cache_size);
661 if (r->l2_table_cache == NULL || r->refcount_block_cache == NULL) {
662 error_setg(errp, "Could not allocate metadata caches");
663 ret = -ENOMEM;
664 goto fail;
665 }
666
667 /* New interval for cache cleanup timer */
668 r->cache_clean_interval =
669 qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL,
670 s->cache_clean_interval);
671 if (r->cache_clean_interval > UINT_MAX) {
672 error_setg(errp, "Cache clean interval too big");
673 ret = -EINVAL;
674 goto fail;
675 }
676
677 /* lazy-refcounts; flush if going from enabled to disabled */
678 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
679 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
680 if (r->use_lazy_refcounts && s->qcow_version < 3) {
681 error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
682 "qemu 1.1 compatibility level");
683 ret = -EINVAL;
684 goto fail;
685 }
686
687 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) {
688 ret = qcow2_mark_clean(bs);
689 if (ret < 0) {
690 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts");
691 goto fail;
692 }
693 }
694
695 /* Overlap check options */
696 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
697 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
698 if (opt_overlap_check_template && opt_overlap_check &&
699 strcmp(opt_overlap_check_template, opt_overlap_check))
700 {
701 error_setg(errp, "Conflicting values for qcow2 options '"
702 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
703 "' ('%s')", opt_overlap_check, opt_overlap_check_template);
704 ret = -EINVAL;
705 goto fail;
706 }
707 if (!opt_overlap_check) {
708 opt_overlap_check = opt_overlap_check_template ?: "cached";
709 }
710
711 if (!strcmp(opt_overlap_check, "none")) {
712 overlap_check_template = 0;
713 } else if (!strcmp(opt_overlap_check, "constant")) {
714 overlap_check_template = QCOW2_OL_CONSTANT;
715 } else if (!strcmp(opt_overlap_check, "cached")) {
716 overlap_check_template = QCOW2_OL_CACHED;
717 } else if (!strcmp(opt_overlap_check, "all")) {
718 overlap_check_template = QCOW2_OL_ALL;
719 } else {
720 error_setg(errp, "Unsupported value '%s' for qcow2 option "
721 "'overlap-check'. Allowed are any of the following: "
722 "none, constant, cached, all", opt_overlap_check);
723 ret = -EINVAL;
724 goto fail;
725 }
726
727 r->overlap_check = 0;
728 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
729 /* overlap-check defines a template bitmask, but every flag may be
730 * overwritten through the associated boolean option */
731 r->overlap_check |=
732 qemu_opt_get_bool(opts, overlap_bool_option_names[i],
733 overlap_check_template & (1 << i)) << i;
734 }
735
736 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
737 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
738 r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
739 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
740 flags & BDRV_O_UNMAP);
741 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
742 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
743 r->discard_passthrough[QCOW2_DISCARD_OTHER] =
744 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
745
746 ret = 0;
747 fail:
748 qemu_opts_del(opts);
749 opts = NULL;
750 return ret;
751 }
752
753 static void qcow2_update_options_commit(BlockDriverState *bs,
754 Qcow2ReopenState *r)
755 {
756 BDRVQcow2State *s = bs->opaque;
757 int i;
758
759 if (s->l2_table_cache) {
760 qcow2_cache_destroy(bs, s->l2_table_cache);
761 }
762 if (s->refcount_block_cache) {
763 qcow2_cache_destroy(bs, s->refcount_block_cache);
764 }
765 s->l2_table_cache = r->l2_table_cache;
766 s->refcount_block_cache = r->refcount_block_cache;
767
768 s->overlap_check = r->overlap_check;
769 s->use_lazy_refcounts = r->use_lazy_refcounts;
770
771 for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
772 s->discard_passthrough[i] = r->discard_passthrough[i];
773 }
774
775 if (s->cache_clean_interval != r->cache_clean_interval) {
776 cache_clean_timer_del(bs);
777 s->cache_clean_interval = r->cache_clean_interval;
778 cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
779 }
780 }
781
782 static void qcow2_update_options_abort(BlockDriverState *bs,
783 Qcow2ReopenState *r)
784 {
785 if (r->l2_table_cache) {
786 qcow2_cache_destroy(bs, r->l2_table_cache);
787 }
788 if (r->refcount_block_cache) {
789 qcow2_cache_destroy(bs, r->refcount_block_cache);
790 }
791 }
792
793 static int qcow2_update_options(BlockDriverState *bs, QDict *options,
794 int flags, Error **errp)
795 {
796 Qcow2ReopenState r = {};
797 int ret;
798
799 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
800 if (ret >= 0) {
801 qcow2_update_options_commit(bs, &r);
802 } else {
803 qcow2_update_options_abort(bs, &r);
804 }
805
806 return ret;
807 }
808
809 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
810 Error **errp)
811 {
812 BDRVQcow2State *s = bs->opaque;
813 unsigned int len, i;
814 int ret = 0;
815 QCowHeader header;
816 Error *local_err = NULL;
817 uint64_t ext_end;
818 uint64_t l1_vm_state_index;
819
820 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header));
821 if (ret < 0) {
822 error_setg_errno(errp, -ret, "Could not read qcow2 header");
823 goto fail;
824 }
825 be32_to_cpus(&header.magic);
826 be32_to_cpus(&header.version);
827 be64_to_cpus(&header.backing_file_offset);
828 be32_to_cpus(&header.backing_file_size);
829 be64_to_cpus(&header.size);
830 be32_to_cpus(&header.cluster_bits);
831 be32_to_cpus(&header.crypt_method);
832 be64_to_cpus(&header.l1_table_offset);
833 be32_to_cpus(&header.l1_size);
834 be64_to_cpus(&header.refcount_table_offset);
835 be32_to_cpus(&header.refcount_table_clusters);
836 be64_to_cpus(&header.snapshots_offset);
837 be32_to_cpus(&header.nb_snapshots);
838
839 if (header.magic != QCOW_MAGIC) {
840 error_setg(errp, "Image is not in qcow2 format");
841 ret = -EINVAL;
842 goto fail;
843 }
844 if (header.version < 2 || header.version > 3) {
845 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version);
846 ret = -ENOTSUP;
847 goto fail;
848 }
849
850 s->qcow_version = header.version;
851
852 /* Initialise cluster size */
853 if (header.cluster_bits < MIN_CLUSTER_BITS ||
854 header.cluster_bits > MAX_CLUSTER_BITS) {
855 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
856 header.cluster_bits);
857 ret = -EINVAL;
858 goto fail;
859 }
860
861 s->cluster_bits = header.cluster_bits;
862 s->cluster_size = 1 << s->cluster_bits;
863 s->cluster_sectors = 1 << (s->cluster_bits - 9);
864
865 /* Initialise version 3 header fields */
866 if (header.version == 2) {
867 header.incompatible_features = 0;
868 header.compatible_features = 0;
869 header.autoclear_features = 0;
870 header.refcount_order = 4;
871 header.header_length = 72;
872 } else {
873 be64_to_cpus(&header.incompatible_features);
874 be64_to_cpus(&header.compatible_features);
875 be64_to_cpus(&header.autoclear_features);
876 be32_to_cpus(&header.refcount_order);
877 be32_to_cpus(&header.header_length);
878
879 if (header.header_length < 104) {
880 error_setg(errp, "qcow2 header too short");
881 ret = -EINVAL;
882 goto fail;
883 }
884 }
885
886 if (header.header_length > s->cluster_size) {
887 error_setg(errp, "qcow2 header exceeds cluster size");
888 ret = -EINVAL;
889 goto fail;
890 }
891
892 if (header.header_length > sizeof(header)) {
893 s->unknown_header_fields_size = header.header_length - sizeof(header);
894 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
895 ret = bdrv_pread(bs->file->bs, sizeof(header), s->unknown_header_fields,
896 s->unknown_header_fields_size);
897 if (ret < 0) {
898 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
899 "fields");
900 goto fail;
901 }
902 }
903
904 if (header.backing_file_offset > s->cluster_size) {
905 error_setg(errp, "Invalid backing file offset");
906 ret = -EINVAL;
907 goto fail;
908 }
909
910 if (header.backing_file_offset) {
911 ext_end = header.backing_file_offset;
912 } else {
913 ext_end = 1 << header.cluster_bits;
914 }
915
916 /* Handle feature bits */
917 s->incompatible_features = header.incompatible_features;
918 s->compatible_features = header.compatible_features;
919 s->autoclear_features = header.autoclear_features;
920
921 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
922 void *feature_table = NULL;
923 qcow2_read_extensions(bs, header.header_length, ext_end,
924 &feature_table, NULL);
925 report_unsupported_feature(errp, feature_table,
926 s->incompatible_features &
927 ~QCOW2_INCOMPAT_MASK);
928 ret = -ENOTSUP;
929 g_free(feature_table);
930 goto fail;
931 }
932
933 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
934 /* Corrupt images may not be written to unless they are being repaired
935 */
936 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
937 error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
938 "read/write");
939 ret = -EACCES;
940 goto fail;
941 }
942 }
943
944 /* Check support for various header values */
945 if (header.refcount_order > 6) {
946 error_setg(errp, "Reference count entry width too large; may not "
947 "exceed 64 bits");
948 ret = -EINVAL;
949 goto fail;
950 }
951 s->refcount_order = header.refcount_order;
952 s->refcount_bits = 1 << s->refcount_order;
953 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
954 s->refcount_max += s->refcount_max - 1;
955
956 if (header.crypt_method > QCOW_CRYPT_AES) {
957 error_setg(errp, "Unsupported encryption method: %" PRIu32,
958 header.crypt_method);
959 ret = -EINVAL;
960 goto fail;
961 }
962 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
963 error_setg(errp, "AES cipher not available");
964 ret = -EINVAL;
965 goto fail;
966 }
967 s->crypt_method_header = header.crypt_method;
968 if (s->crypt_method_header) {
969 if (bdrv_uses_whitelist() &&
970 s->crypt_method_header == QCOW_CRYPT_AES) {
971 error_report("qcow2 built-in AES encryption is deprecated");
972 error_printf("Support for it will be removed in a future release.\n"
973 "You can use 'qemu-img convert' to switch to an\n"
974 "unencrypted qcow2 image, or a LUKS raw image.\n");
975 }
976
977 bs->encrypted = 1;
978 }
979
980 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
981 s->l2_size = 1 << s->l2_bits;
982 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
983 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
984 s->refcount_block_size = 1 << s->refcount_block_bits;
985 bs->total_sectors = header.size / 512;
986 s->csize_shift = (62 - (s->cluster_bits - 8));
987 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
988 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
989
990 s->refcount_table_offset = header.refcount_table_offset;
991 s->refcount_table_size =
992 header.refcount_table_clusters << (s->cluster_bits - 3);
993
994 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) {
995 error_setg(errp, "Reference count table too large");
996 ret = -EINVAL;
997 goto fail;
998 }
999
1000 ret = validate_table_offset(bs, s->refcount_table_offset,
1001 s->refcount_table_size, sizeof(uint64_t));
1002 if (ret < 0) {
1003 error_setg(errp, "Invalid reference count table offset");
1004 goto fail;
1005 }
1006
1007 /* Snapshot table offset/length */
1008 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) {
1009 error_setg(errp, "Too many snapshots");
1010 ret = -EINVAL;
1011 goto fail;
1012 }
1013
1014 ret = validate_table_offset(bs, header.snapshots_offset,
1015 header.nb_snapshots,
1016 sizeof(QCowSnapshotHeader));
1017 if (ret < 0) {
1018 error_setg(errp, "Invalid snapshot table offset");
1019 goto fail;
1020 }
1021
1022 /* read the level 1 table */
1023 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
1024 error_setg(errp, "Active L1 table too large");
1025 ret = -EFBIG;
1026 goto fail;
1027 }
1028 s->l1_size = header.l1_size;
1029
1030 l1_vm_state_index = size_to_l1(s, header.size);
1031 if (l1_vm_state_index > INT_MAX) {
1032 error_setg(errp, "Image is too big");
1033 ret = -EFBIG;
1034 goto fail;
1035 }
1036 s->l1_vm_state_index = l1_vm_state_index;
1037
1038 /* the L1 table must contain at least enough entries to put
1039 header.size bytes */
1040 if (s->l1_size < s->l1_vm_state_index) {
1041 error_setg(errp, "L1 table is too small");
1042 ret = -EINVAL;
1043 goto fail;
1044 }
1045
1046 ret = validate_table_offset(bs, header.l1_table_offset,
1047 header.l1_size, sizeof(uint64_t));
1048 if (ret < 0) {
1049 error_setg(errp, "Invalid L1 table offset");
1050 goto fail;
1051 }
1052 s->l1_table_offset = header.l1_table_offset;
1053
1054
1055 if (s->l1_size > 0) {
1056 s->l1_table = qemu_try_blockalign(bs->file->bs,
1057 align_offset(s->l1_size * sizeof(uint64_t), 512));
1058 if (s->l1_table == NULL) {
1059 error_setg(errp, "Could not allocate L1 table");
1060 ret = -ENOMEM;
1061 goto fail;
1062 }
1063 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table,
1064 s->l1_size * sizeof(uint64_t));
1065 if (ret < 0) {
1066 error_setg_errno(errp, -ret, "Could not read L1 table");
1067 goto fail;
1068 }
1069 for(i = 0;i < s->l1_size; i++) {
1070 be64_to_cpus(&s->l1_table[i]);
1071 }
1072 }
1073
1074 /* Parse driver-specific options */
1075 ret = qcow2_update_options(bs, options, flags, errp);
1076 if (ret < 0) {
1077 goto fail;
1078 }
1079
1080 s->cluster_cache = g_malloc(s->cluster_size);
1081 /* one more sector for decompressed data alignment */
1082 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS
1083 * s->cluster_size + 512);
1084 if (s->cluster_data == NULL) {
1085 error_setg(errp, "Could not allocate temporary cluster buffer");
1086 ret = -ENOMEM;
1087 goto fail;
1088 }
1089
1090 s->cluster_cache_offset = -1;
1091 s->flags = flags;
1092
1093 ret = qcow2_refcount_init(bs);
1094 if (ret != 0) {
1095 error_setg_errno(errp, -ret, "Could not initialize refcount handling");
1096 goto fail;
1097 }
1098
1099 QLIST_INIT(&s->cluster_allocs);
1100 QTAILQ_INIT(&s->discards);
1101
1102 /* read qcow2 extensions */
1103 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
1104 &local_err)) {
1105 error_propagate(errp, local_err);
1106 ret = -EINVAL;
1107 goto fail;
1108 }
1109
1110 /* read the backing file name */
1111 if (header.backing_file_offset != 0) {
1112 len = header.backing_file_size;
1113 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
1114 len >= sizeof(bs->backing_file)) {
1115 error_setg(errp, "Backing file name too long");
1116 ret = -EINVAL;
1117 goto fail;
1118 }
1119 ret = bdrv_pread(bs->file->bs, header.backing_file_offset,
1120 bs->backing_file, len);
1121 if (ret < 0) {
1122 error_setg_errno(errp, -ret, "Could not read backing file name");
1123 goto fail;
1124 }
1125 bs->backing_file[len] = '\0';
1126 s->image_backing_file = g_strdup(bs->backing_file);
1127 }
1128
1129 /* Internal snapshots */
1130 s->snapshots_offset = header.snapshots_offset;
1131 s->nb_snapshots = header.nb_snapshots;
1132
1133 ret = qcow2_read_snapshots(bs);
1134 if (ret < 0) {
1135 error_setg_errno(errp, -ret, "Could not read snapshots");
1136 goto fail;
1137 }
1138
1139 /* Clear unknown autoclear feature bits */
1140 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) {
1141 s->autoclear_features = 0;
1142 ret = qcow2_update_header(bs);
1143 if (ret < 0) {
1144 error_setg_errno(errp, -ret, "Could not update qcow2 header");
1145 goto fail;
1146 }
1147 }
1148
1149 /* Initialise locks */
1150 qemu_co_mutex_init(&s->lock);
1151
1152 /* Repair image if dirty */
1153 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
1154 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
1155 BdrvCheckResult result = {0};
1156
1157 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
1158 if (ret < 0) {
1159 error_setg_errno(errp, -ret, "Could not repair dirty image");
1160 goto fail;
1161 }
1162 }
1163
1164 #ifdef DEBUG_ALLOC
1165 {
1166 BdrvCheckResult result = {0};
1167 qcow2_check_refcounts(bs, &result, 0);
1168 }
1169 #endif
1170 return ret;
1171
1172 fail:
1173 g_free(s->unknown_header_fields);
1174 cleanup_unknown_header_ext(bs);
1175 qcow2_free_snapshots(bs);
1176 qcow2_refcount_close(bs);
1177 qemu_vfree(s->l1_table);
1178 /* else pre-write overlap checks in cache_destroy may crash */
1179 s->l1_table = NULL;
1180 cache_clean_timer_del(bs);
1181 if (s->l2_table_cache) {
1182 qcow2_cache_destroy(bs, s->l2_table_cache);
1183 }
1184 if (s->refcount_block_cache) {
1185 qcow2_cache_destroy(bs, s->refcount_block_cache);
1186 }
1187 g_free(s->cluster_cache);
1188 qemu_vfree(s->cluster_data);
1189 return ret;
1190 }
1191
1192 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
1193 {
1194 BDRVQcow2State *s = bs->opaque;
1195
1196 bs->bl.write_zeroes_alignment = s->cluster_sectors;
1197 }
1198
1199 static int qcow2_set_key(BlockDriverState *bs, const char *key)
1200 {
1201 BDRVQcow2State *s = bs->opaque;
1202 uint8_t keybuf[16];
1203 int len, i;
1204 Error *err = NULL;
1205
1206 memset(keybuf, 0, 16);
1207 len = strlen(key);
1208 if (len > 16)
1209 len = 16;
1210 /* XXX: we could compress the chars to 7 bits to increase
1211 entropy */
1212 for(i = 0;i < len;i++) {
1213 keybuf[i] = key[i];
1214 }
1215 assert(bs->encrypted);
1216
1217 qcrypto_cipher_free(s->cipher);
1218 s->cipher = qcrypto_cipher_new(
1219 QCRYPTO_CIPHER_ALG_AES_128,
1220 QCRYPTO_CIPHER_MODE_CBC,
1221 keybuf, G_N_ELEMENTS(keybuf),
1222 &err);
1223
1224 if (!s->cipher) {
1225 /* XXX would be nice if errors in this method could
1226 * be properly propagate to the caller. Would need
1227 * the bdrv_set_key() API signature to be fixed. */
1228 error_free(err);
1229 return -1;
1230 }
1231 return 0;
1232 }
1233
1234 static int qcow2_reopen_prepare(BDRVReopenState *state,
1235 BlockReopenQueue *queue, Error **errp)
1236 {
1237 Qcow2ReopenState *r;
1238 int ret;
1239
1240 r = g_new0(Qcow2ReopenState, 1);
1241 state->opaque = r;
1242
1243 ret = qcow2_update_options_prepare(state->bs, r, state->options,
1244 state->flags, errp);
1245 if (ret < 0) {
1246 goto fail;
1247 }
1248
1249 /* We need to write out any unwritten data if we reopen read-only. */
1250 if ((state->flags & BDRV_O_RDWR) == 0) {
1251 ret = bdrv_flush(state->bs);
1252 if (ret < 0) {
1253 goto fail;
1254 }
1255
1256 ret = qcow2_mark_clean(state->bs);
1257 if (ret < 0) {
1258 goto fail;
1259 }
1260 }
1261
1262 return 0;
1263
1264 fail:
1265 qcow2_update_options_abort(state->bs, r);
1266 g_free(r);
1267 return ret;
1268 }
1269
1270 static void qcow2_reopen_commit(BDRVReopenState *state)
1271 {
1272 qcow2_update_options_commit(state->bs, state->opaque);
1273 g_free(state->opaque);
1274 }
1275
1276 static void qcow2_reopen_abort(BDRVReopenState *state)
1277 {
1278 qcow2_update_options_abort(state->bs, state->opaque);
1279 g_free(state->opaque);
1280 }
1281
1282 static void qcow2_join_options(QDict *options, QDict *old_options)
1283 {
1284 bool has_new_overlap_template =
1285 qdict_haskey(options, QCOW2_OPT_OVERLAP) ||
1286 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);
1287 bool has_new_total_cache_size =
1288 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);
1289 bool has_all_cache_options;
1290
1291 /* New overlap template overrides all old overlap options */
1292 if (has_new_overlap_template) {
1293 qdict_del(old_options, QCOW2_OPT_OVERLAP);
1294 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);
1295 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);
1296 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);
1297 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);
1298 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);
1299 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);
1300 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);
1301 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);
1302 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);
1303 }
1304
1305 /* New total cache size overrides all old options */
1306 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {
1307 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);
1308 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1309 }
1310
1311 qdict_join(options, old_options, false);
1312
1313 /*
1314 * If after merging all cache size options are set, an old total size is
1315 * overwritten. Do keep all options, however, if all three are new. The
1316 * resulting error message is what we want to happen.
1317 */
1318 has_all_cache_options =
1319 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||
1320 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||
1321 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1322
1323 if (has_all_cache_options && !has_new_total_cache_size) {
1324 qdict_del(options, QCOW2_OPT_CACHE_SIZE);
1325 }
1326 }
1327
1328 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
1329 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
1330 {
1331 BDRVQcow2State *s = bs->opaque;
1332 uint64_t cluster_offset;
1333 int index_in_cluster, ret;
1334 int64_t status = 0;
1335
1336 *pnum = nb_sectors;
1337 qemu_co_mutex_lock(&s->lock);
1338 ret = qcow2_get_cluster_offset(bs, sector_num << 9, pnum, &cluster_offset);
1339 qemu_co_mutex_unlock(&s->lock);
1340 if (ret < 0) {
1341 return ret;
1342 }
1343
1344 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED &&
1345 !s->cipher) {
1346 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1347 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
1348 *file = bs->file->bs;
1349 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset;
1350 }
1351 if (ret == QCOW2_CLUSTER_ZERO) {
1352 status |= BDRV_BLOCK_ZERO;
1353 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
1354 status |= BDRV_BLOCK_DATA;
1355 }
1356 return status;
1357 }
1358
1359 /* handle reading after the end of the backing file */
1360 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
1361 int64_t sector_num, int nb_sectors)
1362 {
1363 int n1;
1364 if ((sector_num + nb_sectors) <= bs->total_sectors)
1365 return nb_sectors;
1366 if (sector_num >= bs->total_sectors)
1367 n1 = 0;
1368 else
1369 n1 = bs->total_sectors - sector_num;
1370
1371 qemu_iovec_memset(qiov, 512 * n1, 0, 512 * (nb_sectors - n1));
1372
1373 return n1;
1374 }
1375
1376 static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
1377 int remaining_sectors, QEMUIOVector *qiov)
1378 {
1379 BDRVQcow2State *s = bs->opaque;
1380 int index_in_cluster, n1;
1381 int ret;
1382 int cur_nr_sectors; /* number of sectors in current iteration */
1383 uint64_t cluster_offset = 0;
1384 uint64_t bytes_done = 0;
1385 QEMUIOVector hd_qiov;
1386 uint8_t *cluster_data = NULL;
1387
1388 qemu_iovec_init(&hd_qiov, qiov->niov);
1389
1390 qemu_co_mutex_lock(&s->lock);
1391
1392 while (remaining_sectors != 0) {
1393
1394 /* prepare next request */
1395 cur_nr_sectors = remaining_sectors;
1396 if (s->cipher) {
1397 cur_nr_sectors = MIN(cur_nr_sectors,
1398 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
1399 }
1400
1401 ret = qcow2_get_cluster_offset(bs, sector_num << 9,
1402 &cur_nr_sectors, &cluster_offset);
1403 if (ret < 0) {
1404 goto fail;
1405 }
1406
1407 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1408
1409 qemu_iovec_reset(&hd_qiov);
1410 qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1411 cur_nr_sectors * 512);
1412
1413 switch (ret) {
1414 case QCOW2_CLUSTER_UNALLOCATED:
1415
1416 if (bs->backing) {
1417 /* read from the base image */
1418 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov,
1419 sector_num, cur_nr_sectors);
1420 if (n1 > 0) {
1421 QEMUIOVector local_qiov;
1422
1423 qemu_iovec_init(&local_qiov, hd_qiov.niov);
1424 qemu_iovec_concat(&local_qiov, &hd_qiov, 0,
1425 n1 * BDRV_SECTOR_SIZE);
1426
1427 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
1428 qemu_co_mutex_unlock(&s->lock);
1429 ret = bdrv_co_readv(bs->backing->bs, sector_num,
1430 n1, &local_qiov);
1431 qemu_co_mutex_lock(&s->lock);
1432
1433 qemu_iovec_destroy(&local_qiov);
1434
1435 if (ret < 0) {
1436 goto fail;
1437 }
1438 }
1439 } else {
1440 /* Note: in this case, no need to wait */
1441 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
1442 }
1443 break;
1444
1445 case QCOW2_CLUSTER_ZERO:
1446 qemu_iovec_memset(&hd_qiov, 0, 0, 512 * cur_nr_sectors);
1447 break;
1448
1449 case QCOW2_CLUSTER_COMPRESSED:
1450 /* add AIO support for compressed blocks ? */
1451 ret = qcow2_decompress_cluster(bs, cluster_offset);
1452 if (ret < 0) {
1453 goto fail;
1454 }
1455
1456 qemu_iovec_from_buf(&hd_qiov, 0,
1457 s->cluster_cache + index_in_cluster * 512,
1458 512 * cur_nr_sectors);
1459 break;
1460
1461 case QCOW2_CLUSTER_NORMAL:
1462 if ((cluster_offset & 511) != 0) {
1463 ret = -EIO;
1464 goto fail;
1465 }
1466
1467 if (bs->encrypted) {
1468 assert(s->cipher);
1469
1470 /*
1471 * For encrypted images, read everything into a temporary
1472 * contiguous buffer on which the AES functions can work.
1473 */
1474 if (!cluster_data) {
1475 cluster_data =
1476 qemu_try_blockalign(bs->file->bs,
1477 QCOW_MAX_CRYPT_CLUSTERS
1478 * s->cluster_size);
1479 if (cluster_data == NULL) {
1480 ret = -ENOMEM;
1481 goto fail;
1482 }
1483 }
1484
1485 assert(cur_nr_sectors <=
1486 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors);
1487 qemu_iovec_reset(&hd_qiov);
1488 qemu_iovec_add(&hd_qiov, cluster_data,
1489 512 * cur_nr_sectors);
1490 }
1491
1492 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
1493 qemu_co_mutex_unlock(&s->lock);
1494 ret = bdrv_co_readv(bs->file->bs,
1495 (cluster_offset >> 9) + index_in_cluster,
1496 cur_nr_sectors, &hd_qiov);
1497 qemu_co_mutex_lock(&s->lock);
1498 if (ret < 0) {
1499 goto fail;
1500 }
1501 if (bs->encrypted) {
1502 assert(s->cipher);
1503 Error *err = NULL;
1504 if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
1505 cluster_data, cur_nr_sectors, false,
1506 &err) < 0) {
1507 error_free(err);
1508 ret = -EIO;
1509 goto fail;
1510 }
1511 qemu_iovec_from_buf(qiov, bytes_done,
1512 cluster_data, 512 * cur_nr_sectors);
1513 }
1514 break;
1515
1516 default:
1517 g_assert_not_reached();
1518 ret = -EIO;
1519 goto fail;
1520 }
1521
1522 remaining_sectors -= cur_nr_sectors;
1523 sector_num += cur_nr_sectors;
1524 bytes_done += cur_nr_sectors * 512;
1525 }
1526 ret = 0;
1527
1528 fail:
1529 qemu_co_mutex_unlock(&s->lock);
1530
1531 qemu_iovec_destroy(&hd_qiov);
1532 qemu_vfree(cluster_data);
1533
1534 return ret;
1535 }
1536
1537 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
1538 int64_t sector_num,
1539 int remaining_sectors,
1540 QEMUIOVector *qiov)
1541 {
1542 BDRVQcow2State *s = bs->opaque;
1543 int index_in_cluster;
1544 int ret;
1545 int cur_nr_sectors; /* number of sectors in current iteration */
1546 uint64_t cluster_offset;
1547 QEMUIOVector hd_qiov;
1548 uint64_t bytes_done = 0;
1549 uint8_t *cluster_data = NULL;
1550 QCowL2Meta *l2meta = NULL;
1551
1552 trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num,
1553 remaining_sectors);
1554
1555 qemu_iovec_init(&hd_qiov, qiov->niov);
1556
1557 s->cluster_cache_offset = -1; /* disable compressed cache */
1558
1559 qemu_co_mutex_lock(&s->lock);
1560
1561 while (remaining_sectors != 0) {
1562
1563 l2meta = NULL;
1564
1565 trace_qcow2_writev_start_part(qemu_coroutine_self());
1566 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1567 cur_nr_sectors = remaining_sectors;
1568 if (bs->encrypted &&
1569 cur_nr_sectors >
1570 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) {
1571 cur_nr_sectors =
1572 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster;
1573 }
1574
1575 ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,
1576 &cur_nr_sectors, &cluster_offset, &l2meta);
1577 if (ret < 0) {
1578 goto fail;
1579 }
1580
1581 assert((cluster_offset & 511) == 0);
1582
1583 qemu_iovec_reset(&hd_qiov);
1584 qemu_iovec_concat(&hd_qiov, qiov, bytes_done,
1585 cur_nr_sectors * 512);
1586
1587 if (bs->encrypted) {
1588 Error *err = NULL;
1589 assert(s->cipher);
1590 if (!cluster_data) {
1591 cluster_data = qemu_try_blockalign(bs->file->bs,
1592 QCOW_MAX_CRYPT_CLUSTERS
1593 * s->cluster_size);
1594 if (cluster_data == NULL) {
1595 ret = -ENOMEM;
1596 goto fail;
1597 }
1598 }
1599
1600 assert(hd_qiov.size <=
1601 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1602 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
1603
1604 if (qcow2_encrypt_sectors(s, sector_num, cluster_data,
1605 cluster_data, cur_nr_sectors,
1606 true, &err) < 0) {
1607 error_free(err);
1608 ret = -EIO;
1609 goto fail;
1610 }
1611
1612 qemu_iovec_reset(&hd_qiov);
1613 qemu_iovec_add(&hd_qiov, cluster_data,
1614 cur_nr_sectors * 512);
1615 }
1616
1617 ret = qcow2_pre_write_overlap_check(bs, 0,
1618 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE,
1619 cur_nr_sectors * BDRV_SECTOR_SIZE);
1620 if (ret < 0) {
1621 goto fail;
1622 }
1623
1624 qemu_co_mutex_unlock(&s->lock);
1625 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
1626 trace_qcow2_writev_data(qemu_coroutine_self(),
1627 (cluster_offset >> 9) + index_in_cluster);
1628 ret = bdrv_co_writev(bs->file->bs,
1629 (cluster_offset >> 9) + index_in_cluster,
1630 cur_nr_sectors, &hd_qiov);
1631 qemu_co_mutex_lock(&s->lock);
1632 if (ret < 0) {
1633 goto fail;
1634 }
1635
1636 while (l2meta != NULL) {
1637 QCowL2Meta *next;
1638
1639 ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
1640 if (ret < 0) {
1641 goto fail;
1642 }
1643
1644 /* Take the request off the list of running requests */
1645 if (l2meta->nb_clusters != 0) {
1646 QLIST_REMOVE(l2meta, next_in_flight);
1647 }
1648
1649 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1650
1651 next = l2meta->next;
1652 g_free(l2meta);
1653 l2meta = next;
1654 }
1655
1656 remaining_sectors -= cur_nr_sectors;
1657 sector_num += cur_nr_sectors;
1658 bytes_done += cur_nr_sectors * 512;
1659 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_nr_sectors);
1660 }
1661 ret = 0;
1662
1663 fail:
1664 qemu_co_mutex_unlock(&s->lock);
1665
1666 while (l2meta != NULL) {
1667 QCowL2Meta *next;
1668
1669 if (l2meta->nb_clusters != 0) {
1670 QLIST_REMOVE(l2meta, next_in_flight);
1671 }
1672 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1673
1674 next = l2meta->next;
1675 g_free(l2meta);
1676 l2meta = next;
1677 }
1678
1679 qemu_iovec_destroy(&hd_qiov);
1680 qemu_vfree(cluster_data);
1681 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
1682
1683 return ret;
1684 }
1685
1686 static int qcow2_inactivate(BlockDriverState *bs)
1687 {
1688 BDRVQcow2State *s = bs->opaque;
1689 int ret, result = 0;
1690
1691 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1692 if (ret) {
1693 result = ret;
1694 error_report("Failed to flush the L2 table cache: %s",
1695 strerror(-ret));
1696 }
1697
1698 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1699 if (ret) {
1700 result = ret;
1701 error_report("Failed to flush the refcount block cache: %s",
1702 strerror(-ret));
1703 }
1704
1705 if (result == 0) {
1706 qcow2_mark_clean(bs);
1707 }
1708
1709 return result;
1710 }
1711
1712 static void qcow2_close(BlockDriverState *bs)
1713 {
1714 BDRVQcow2State *s = bs->opaque;
1715 qemu_vfree(s->l1_table);
1716 /* else pre-write overlap checks in cache_destroy may crash */
1717 s->l1_table = NULL;
1718
1719 if (!(s->flags & BDRV_O_INACTIVE)) {
1720 qcow2_inactivate(bs);
1721 }
1722
1723 cache_clean_timer_del(bs);
1724 qcow2_cache_destroy(bs, s->l2_table_cache);
1725 qcow2_cache_destroy(bs, s->refcount_block_cache);
1726
1727 qcrypto_cipher_free(s->cipher);
1728 s->cipher = NULL;
1729
1730 g_free(s->unknown_header_fields);
1731 cleanup_unknown_header_ext(bs);
1732
1733 g_free(s->image_backing_file);
1734 g_free(s->image_backing_format);
1735
1736 g_free(s->cluster_cache);
1737 qemu_vfree(s->cluster_data);
1738 qcow2_refcount_close(bs);
1739 qcow2_free_snapshots(bs);
1740 }
1741
1742 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
1743 {
1744 BDRVQcow2State *s = bs->opaque;
1745 int flags = s->flags;
1746 QCryptoCipher *cipher = NULL;
1747 QDict *options;
1748 Error *local_err = NULL;
1749 int ret;
1750
1751 /*
1752 * Backing files are read-only which makes all of their metadata immutable,
1753 * that means we don't have to worry about reopening them here.
1754 */
1755
1756 cipher = s->cipher;
1757 s->cipher = NULL;
1758
1759 qcow2_close(bs);
1760
1761 memset(s, 0, sizeof(BDRVQcow2State));
1762 options = qdict_clone_shallow(bs->options);
1763
1764 flags &= ~BDRV_O_INACTIVE;
1765 ret = qcow2_open(bs, options, flags, &local_err);
1766 QDECREF(options);
1767 if (local_err) {
1768 error_propagate(errp, local_err);
1769 error_prepend(errp, "Could not reopen qcow2 layer: ");
1770 bs->drv = NULL;
1771 return;
1772 } else if (ret < 0) {
1773 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
1774 bs->drv = NULL;
1775 return;
1776 }
1777
1778 s->cipher = cipher;
1779 }
1780
1781 static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
1782 size_t len, size_t buflen)
1783 {
1784 QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
1785 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
1786
1787 if (buflen < ext_len) {
1788 return -ENOSPC;
1789 }
1790
1791 *ext_backing_fmt = (QCowExtension) {
1792 .magic = cpu_to_be32(magic),
1793 .len = cpu_to_be32(len),
1794 };
1795 memcpy(buf + sizeof(QCowExtension), s, len);
1796
1797 return ext_len;
1798 }
1799
1800 /*
1801 * Updates the qcow2 header, including the variable length parts of it, i.e.
1802 * the backing file name and all extensions. qcow2 was not designed to allow
1803 * such changes, so if we run out of space (we can only use the first cluster)
1804 * this function may fail.
1805 *
1806 * Returns 0 on success, -errno in error cases.
1807 */
1808 int qcow2_update_header(BlockDriverState *bs)
1809 {
1810 BDRVQcow2State *s = bs->opaque;
1811 QCowHeader *header;
1812 char *buf;
1813 size_t buflen = s->cluster_size;
1814 int ret;
1815 uint64_t total_size;
1816 uint32_t refcount_table_clusters;
1817 size_t header_length;
1818 Qcow2UnknownHeaderExtension *uext;
1819
1820 buf = qemu_blockalign(bs, buflen);
1821
1822 /* Header structure */
1823 header = (QCowHeader*) buf;
1824
1825 if (buflen < sizeof(*header)) {
1826 ret = -ENOSPC;
1827 goto fail;
1828 }
1829
1830 header_length = sizeof(*header) + s->unknown_header_fields_size;
1831 total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
1832 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
1833
1834 *header = (QCowHeader) {
1835 /* Version 2 fields */
1836 .magic = cpu_to_be32(QCOW_MAGIC),
1837 .version = cpu_to_be32(s->qcow_version),
1838 .backing_file_offset = 0,
1839 .backing_file_size = 0,
1840 .cluster_bits = cpu_to_be32(s->cluster_bits),
1841 .size = cpu_to_be64(total_size),
1842 .crypt_method = cpu_to_be32(s->crypt_method_header),
1843 .l1_size = cpu_to_be32(s->l1_size),
1844 .l1_table_offset = cpu_to_be64(s->l1_table_offset),
1845 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
1846 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
1847 .nb_snapshots = cpu_to_be32(s->nb_snapshots),
1848 .snapshots_offset = cpu_to_be64(s->snapshots_offset),
1849
1850 /* Version 3 fields */
1851 .incompatible_features = cpu_to_be64(s->incompatible_features),
1852 .compatible_features = cpu_to_be64(s->compatible_features),
1853 .autoclear_features = cpu_to_be64(s->autoclear_features),
1854 .refcount_order = cpu_to_be32(s->refcount_order),
1855 .header_length = cpu_to_be32(header_length),
1856 };
1857
1858 /* For older versions, write a shorter header */
1859 switch (s->qcow_version) {
1860 case 2:
1861 ret = offsetof(QCowHeader, incompatible_features);
1862 break;
1863 case 3:
1864 ret = sizeof(*header);
1865 break;
1866 default:
1867 ret = -EINVAL;
1868 goto fail;
1869 }
1870
1871 buf += ret;
1872 buflen -= ret;
1873 memset(buf, 0, buflen);
1874
1875 /* Preserve any unknown field in the header */
1876 if (s->unknown_header_fields_size) {
1877 if (buflen < s->unknown_header_fields_size) {
1878 ret = -ENOSPC;
1879 goto fail;
1880 }
1881
1882 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
1883 buf += s->unknown_header_fields_size;
1884 buflen -= s->unknown_header_fields_size;
1885 }
1886
1887 /* Backing file format header extension */
1888 if (s->image_backing_format) {
1889 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
1890 s->image_backing_format,
1891 strlen(s->image_backing_format),
1892 buflen);
1893 if (ret < 0) {
1894 goto fail;
1895 }
1896
1897 buf += ret;
1898 buflen -= ret;
1899 }
1900
1901 /* Feature table */
1902 if (s->qcow_version >= 3) {
1903 Qcow2Feature features[] = {
1904 {
1905 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1906 .bit = QCOW2_INCOMPAT_DIRTY_BITNR,
1907 .name = "dirty bit",
1908 },
1909 {
1910 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1911 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
1912 .name = "corrupt bit",
1913 },
1914 {
1915 .type = QCOW2_FEAT_TYPE_COMPATIBLE,
1916 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
1917 .name = "lazy refcounts",
1918 },
1919 };
1920
1921 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
1922 features, sizeof(features), buflen);
1923 if (ret < 0) {
1924 goto fail;
1925 }
1926 buf += ret;
1927 buflen -= ret;
1928 }
1929
1930 /* Keep unknown header extensions */
1931 QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
1932 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
1933 if (ret < 0) {
1934 goto fail;
1935 }
1936
1937 buf += ret;
1938 buflen -= ret;
1939 }
1940
1941 /* End of header extensions */
1942 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
1943 if (ret < 0) {
1944 goto fail;
1945 }
1946
1947 buf += ret;
1948 buflen -= ret;
1949
1950 /* Backing file name */
1951 if (s->image_backing_file) {
1952 size_t backing_file_len = strlen(s->image_backing_file);
1953
1954 if (buflen < backing_file_len) {
1955 ret = -ENOSPC;
1956 goto fail;
1957 }
1958
1959 /* Using strncpy is ok here, since buf is not NUL-terminated. */
1960 strncpy(buf, s->image_backing_file, buflen);
1961
1962 header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
1963 header->backing_file_size = cpu_to_be32(backing_file_len);
1964 }
1965
1966 /* Write the new header */
1967 ret = bdrv_pwrite(bs->file->bs, 0, header, s->cluster_size);
1968 if (ret < 0) {
1969 goto fail;
1970 }
1971
1972 ret = 0;
1973 fail:
1974 qemu_vfree(header);
1975 return ret;
1976 }
1977
1978 static int qcow2_change_backing_file(BlockDriverState *bs,
1979 const char *backing_file, const char *backing_fmt)
1980 {
1981 BDRVQcow2State *s = bs->opaque;
1982
1983 if (backing_file && strlen(backing_file) > 1023) {
1984 return -EINVAL;
1985 }
1986
1987 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
1988 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
1989
1990 g_free(s->image_backing_file);
1991 g_free(s->image_backing_format);
1992
1993 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
1994 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
1995
1996 return qcow2_update_header(bs);
1997 }
1998
1999 static int preallocate(BlockDriverState *bs)
2000 {
2001 uint64_t nb_sectors;
2002 uint64_t offset;
2003 uint64_t host_offset = 0;
2004 int num;
2005 int ret;
2006 QCowL2Meta *meta;
2007
2008 nb_sectors = bdrv_nb_sectors(bs);
2009 offset = 0;
2010
2011 while (nb_sectors) {
2012 num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS);
2013 ret = qcow2_alloc_cluster_offset(bs, offset, &num,
2014 &host_offset, &meta);
2015 if (ret < 0) {
2016 return ret;
2017 }
2018
2019 while (meta) {
2020 QCowL2Meta *next = meta->next;
2021
2022 ret = qcow2_alloc_cluster_link_l2(bs, meta);
2023 if (ret < 0) {
2024 qcow2_free_any_clusters(bs, meta->alloc_offset,
2025 meta->nb_clusters, QCOW2_DISCARD_NEVER);
2026 return ret;
2027 }
2028
2029 /* There are no dependent requests, but we need to remove our
2030 * request from the list of in-flight requests */
2031 QLIST_REMOVE(meta, next_in_flight);
2032
2033 g_free(meta);
2034 meta = next;
2035 }
2036
2037 /* TODO Preallocate data if requested */
2038
2039 nb_sectors -= num;
2040 offset += num << BDRV_SECTOR_BITS;
2041 }
2042
2043 /*
2044 * It is expected that the image file is large enough to actually contain
2045 * all of the allocated clusters (otherwise we get failing reads after
2046 * EOF). Extend the image to the last allocated sector.
2047 */
2048 if (host_offset != 0) {
2049 uint8_t buf[BDRV_SECTOR_SIZE];
2050 memset(buf, 0, BDRV_SECTOR_SIZE);
2051 ret = bdrv_write(bs->file->bs,
2052 (host_offset >> BDRV_SECTOR_BITS) + num - 1,
2053 buf, 1);
2054 if (ret < 0) {
2055 return ret;
2056 }
2057 }
2058
2059 return 0;
2060 }
2061
2062 static int qcow2_create2(const char *filename, int64_t total_size,
2063 const char *backing_file, const char *backing_format,
2064 int flags, size_t cluster_size, PreallocMode prealloc,
2065 QemuOpts *opts, int version, int refcount_order,
2066 Error **errp)
2067 {
2068 int cluster_bits;
2069 QDict *options;
2070
2071 /* Calculate cluster_bits */
2072 cluster_bits = ctz32(cluster_size);
2073 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
2074 (1 << cluster_bits) != cluster_size)
2075 {
2076 error_setg(errp, "Cluster size must be a power of two between %d and "
2077 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
2078 return -EINVAL;
2079 }
2080
2081 /*
2082 * Open the image file and write a minimal qcow2 header.
2083 *
2084 * We keep things simple and start with a zero-sized image. We also
2085 * do without refcount blocks or a L1 table for now. We'll fix the
2086 * inconsistency later.
2087 *
2088 * We do need a refcount table because growing the refcount table means
2089 * allocating two new refcount blocks - the seconds of which would be at
2090 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
2091 * size for any qcow2 image.
2092 */
2093 BlockBackend *blk;
2094 QCowHeader *header;
2095 uint64_t* refcount_table;
2096 Error *local_err = NULL;
2097 int ret;
2098
2099 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
2100 /* Note: The following calculation does not need to be exact; if it is a
2101 * bit off, either some bytes will be "leaked" (which is fine) or we
2102 * will need to increase the file size by some bytes (which is fine,
2103 * too, as long as the bulk is allocated here). Therefore, using
2104 * floating point arithmetic is fine. */
2105 int64_t meta_size = 0;
2106 uint64_t nreftablee, nrefblocke, nl1e, nl2e;
2107 int64_t aligned_total_size = align_offset(total_size, cluster_size);
2108 int refblock_bits, refblock_size;
2109 /* refcount entry size in bytes */
2110 double rces = (1 << refcount_order) / 8.;
2111
2112 /* see qcow2_open() */
2113 refblock_bits = cluster_bits - (refcount_order - 3);
2114 refblock_size = 1 << refblock_bits;
2115
2116 /* header: 1 cluster */
2117 meta_size += cluster_size;
2118
2119 /* total size of L2 tables */
2120 nl2e = aligned_total_size / cluster_size;
2121 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
2122 meta_size += nl2e * sizeof(uint64_t);
2123
2124 /* total size of L1 tables */
2125 nl1e = nl2e * sizeof(uint64_t) / cluster_size;
2126 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t));
2127 meta_size += nl1e * sizeof(uint64_t);
2128
2129 /* total size of refcount blocks
2130 *
2131 * note: every host cluster is reference-counted, including metadata
2132 * (even refcount blocks are recursively included).
2133 * Let:
2134 * a = total_size (this is the guest disk size)
2135 * m = meta size not including refcount blocks and refcount tables
2136 * c = cluster size
2137 * y1 = number of refcount blocks entries
2138 * y2 = meta size including everything
2139 * rces = refcount entry size in bytes
2140 * then,
2141 * y1 = (y2 + a)/c
2142 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m
2143 * we can get y1:
2144 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c)
2145 */
2146 nrefblocke = (aligned_total_size + meta_size + cluster_size)
2147 / (cluster_size - rces - rces * sizeof(uint64_t)
2148 / cluster_size);
2149 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size;
2150
2151 /* total size of refcount tables */
2152 nreftablee = nrefblocke / refblock_size;
2153 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t));
2154 meta_size += nreftablee * sizeof(uint64_t);
2155
2156 qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
2157 aligned_total_size + meta_size, &error_abort);
2158 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc],
2159 &error_abort);
2160 }
2161
2162 ret = bdrv_create_file(filename, opts, &local_err);
2163 if (ret < 0) {
2164 error_propagate(errp, local_err);
2165 return ret;
2166 }
2167
2168 blk = blk_new_open(filename, NULL, NULL,
2169 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
2170 if (blk == NULL) {
2171 error_propagate(errp, local_err);
2172 return -EIO;
2173 }
2174
2175 blk_set_allow_write_beyond_eof(blk, true);
2176
2177 /* Write the header */
2178 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
2179 header = g_malloc0(cluster_size);
2180 *header = (QCowHeader) {
2181 .magic = cpu_to_be32(QCOW_MAGIC),
2182 .version = cpu_to_be32(version),
2183 .cluster_bits = cpu_to_be32(cluster_bits),
2184 .size = cpu_to_be64(0),
2185 .l1_table_offset = cpu_to_be64(0),
2186 .l1_size = cpu_to_be32(0),
2187 .refcount_table_offset = cpu_to_be64(cluster_size),
2188 .refcount_table_clusters = cpu_to_be32(1),
2189 .refcount_order = cpu_to_be32(refcount_order),
2190 .header_length = cpu_to_be32(sizeof(*header)),
2191 };
2192
2193 if (flags & BLOCK_FLAG_ENCRYPT) {
2194 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
2195 } else {
2196 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
2197 }
2198
2199 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) {
2200 header->compatible_features |=
2201 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
2202 }
2203
2204 ret = blk_pwrite(blk, 0, header, cluster_size, 0);
2205 g_free(header);
2206 if (ret < 0) {
2207 error_setg_errno(errp, -ret, "Could not write qcow2 header");
2208 goto out;
2209 }
2210
2211 /* Write a refcount table with one refcount block */
2212 refcount_table = g_malloc0(2 * cluster_size);
2213 refcount_table[0] = cpu_to_be64(2 * cluster_size);
2214 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0);
2215 g_free(refcount_table);
2216
2217 if (ret < 0) {
2218 error_setg_errno(errp, -ret, "Could not write refcount table");
2219 goto out;
2220 }
2221
2222 blk_unref(blk);
2223 blk = NULL;
2224
2225 /*
2226 * And now open the image and make it consistent first (i.e. increase the
2227 * refcount of the cluster that is occupied by the header and the refcount
2228 * table)
2229 */
2230 options = qdict_new();
2231 qdict_put(options, "driver", qstring_from_str("qcow2"));
2232 blk = blk_new_open(filename, NULL, options,
2233 BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err);
2234 if (blk == NULL) {
2235 error_propagate(errp, local_err);
2236 ret = -EIO;
2237 goto out;
2238 }
2239
2240 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size);
2241 if (ret < 0) {
2242 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
2243 "header and refcount table");
2244 goto out;
2245
2246 } else if (ret != 0) {
2247 error_report("Huh, first cluster in empty image is already in use?");
2248 abort();
2249 }
2250
2251 /* Create a full header (including things like feature table) */
2252 ret = qcow2_update_header(blk_bs(blk));
2253 if (ret < 0) {
2254 error_setg_errno(errp, -ret, "Could not update qcow2 header");
2255 goto out;
2256 }
2257
2258 /* Okay, now that we have a valid image, let's give it the right size */
2259 ret = blk_truncate(blk, total_size);
2260 if (ret < 0) {
2261 error_setg_errno(errp, -ret, "Could not resize image");
2262 goto out;
2263 }
2264
2265 /* Want a backing file? There you go.*/
2266 if (backing_file) {
2267 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format);
2268 if (ret < 0) {
2269 error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
2270 "with format '%s'", backing_file, backing_format);
2271 goto out;
2272 }
2273 }
2274
2275 /* And if we're supposed to preallocate metadata, do that now */
2276 if (prealloc != PREALLOC_MODE_OFF) {
2277 BDRVQcow2State *s = blk_bs(blk)->opaque;
2278 qemu_co_mutex_lock(&s->lock);
2279 ret = preallocate(blk_bs(blk));
2280 qemu_co_mutex_unlock(&s->lock);
2281 if (ret < 0) {
2282 error_setg_errno(errp, -ret, "Could not preallocate metadata");
2283 goto out;
2284 }
2285 }
2286
2287 blk_unref(blk);
2288 blk = NULL;
2289
2290 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
2291 options = qdict_new();
2292 qdict_put(options, "driver", qstring_from_str("qcow2"));
2293 blk = blk_new_open(filename, NULL, options,
2294 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err);
2295 if (blk == NULL) {
2296 error_propagate(errp, local_err);
2297 ret = -EIO;
2298 goto out;
2299 }
2300
2301 ret = 0;
2302 out:
2303 if (blk) {
2304 blk_unref(blk);
2305 }
2306 return ret;
2307 }
2308
2309 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
2310 {
2311 char *backing_file = NULL;
2312 char *backing_fmt = NULL;
2313 char *buf = NULL;
2314 uint64_t size = 0;
2315 int flags = 0;
2316 size_t cluster_size = DEFAULT_CLUSTER_SIZE;
2317 PreallocMode prealloc;
2318 int version = 3;
2319 uint64_t refcount_bits = 16;
2320 int refcount_order;
2321 Error *local_err = NULL;
2322 int ret;
2323
2324 /* Read out options */
2325 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
2326 BDRV_SECTOR_SIZE);
2327 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
2328 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
2329 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
2330 flags |= BLOCK_FLAG_ENCRYPT;
2331 }
2332 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
2333 DEFAULT_CLUSTER_SIZE);
2334 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
2335 prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
2336 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF,
2337 &local_err);
2338 if (local_err) {
2339 error_propagate(errp, local_err);
2340 ret = -EINVAL;
2341 goto finish;
2342 }
2343 g_free(buf);
2344 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
2345 if (!buf) {
2346 /* keep the default */
2347 } else if (!strcmp(buf, "0.10")) {
2348 version = 2;
2349 } else if (!strcmp(buf, "1.1")) {
2350 version = 3;
2351 } else {
2352 error_setg(errp, "Invalid compatibility level: '%s'", buf);
2353 ret = -EINVAL;
2354 goto finish;
2355 }
2356
2357 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) {
2358 flags |= BLOCK_FLAG_LAZY_REFCOUNTS;
2359 }
2360
2361 if (backing_file && prealloc != PREALLOC_MODE_OFF) {
2362 error_setg(errp, "Backing file and preallocation cannot be used at "
2363 "the same time");
2364 ret = -EINVAL;
2365 goto finish;
2366 }
2367
2368 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) {
2369 error_setg(errp, "Lazy refcounts only supported with compatibility "
2370 "level 1.1 and above (use compat=1.1 or greater)");
2371 ret = -EINVAL;
2372 goto finish;
2373 }
2374
2375 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS,
2376 refcount_bits);
2377 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
2378 error_setg(errp, "Refcount width must be a power of two and may not "
2379 "exceed 64 bits");
2380 ret = -EINVAL;
2381 goto finish;
2382 }
2383
2384 if (version < 3 && refcount_bits != 16) {
2385 error_setg(errp, "Different refcount widths than 16 bits require "
2386 "compatibility level 1.1 or above (use compat=1.1 or "
2387 "greater)");
2388 ret = -EINVAL;
2389 goto finish;
2390 }
2391
2392 refcount_order = ctz32(refcount_bits);
2393
2394 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags,
2395 cluster_size, prealloc, opts, version, refcount_order,
2396 &local_err);
2397 if (local_err) {
2398 error_propagate(errp, local_err);
2399 }
2400
2401 finish:
2402 g_free(backing_file);
2403 g_free(backing_fmt);
2404 g_free(buf);
2405 return ret;
2406 }
2407
2408
2409 static bool is_zero_cluster(BlockDriverState *bs, int64_t start)
2410 {
2411 BDRVQcow2State *s = bs->opaque;
2412 int nr;
2413 BlockDriverState *file;
2414 int64_t res = bdrv_get_block_status_above(bs, NULL, start,
2415 s->cluster_sectors, &nr, &file);
2416 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == s->cluster_sectors;
2417 }
2418
2419 static bool is_zero_cluster_top_locked(BlockDriverState *bs, int64_t start)
2420 {
2421 BDRVQcow2State *s = bs->opaque;
2422 int nr = s->cluster_sectors;
2423 uint64_t off;
2424 int ret;
2425
2426 ret = qcow2_get_cluster_offset(bs, start << BDRV_SECTOR_BITS, &nr, &off);
2427 assert(nr == s->cluster_sectors);
2428 return ret == QCOW2_CLUSTER_UNALLOCATED || ret == QCOW2_CLUSTER_ZERO;
2429 }
2430
2431 static coroutine_fn int qcow2_co_write_zeroes(BlockDriverState *bs,
2432 int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
2433 {
2434 int ret;
2435 BDRVQcow2State *s = bs->opaque;
2436
2437 int head = sector_num % s->cluster_sectors;
2438 int tail = (sector_num + nb_sectors) % s->cluster_sectors;
2439
2440 if (head != 0 || tail != 0) {
2441 int64_t cl_end = -1;
2442
2443 sector_num -= head;
2444 nb_sectors += head;
2445
2446 if (tail != 0) {
2447 nb_sectors += s->cluster_sectors - tail;
2448 }
2449
2450 if (!is_zero_cluster(bs, sector_num)) {
2451 return -ENOTSUP;
2452 }
2453
2454 if (nb_sectors > s->cluster_sectors) {
2455 /* Technically the request can cover 2 clusters, f.e. 4k write
2456 at s->cluster_sectors - 2k offset. One of these cluster can
2457 be zeroed, one unallocated */
2458 cl_end = sector_num + nb_sectors - s->cluster_sectors;
2459 if (!is_zero_cluster(bs, cl_end)) {
2460 return -ENOTSUP;
2461 }
2462 }
2463
2464 qemu_co_mutex_lock(&s->lock);
2465 /* We can have new write after previous check */
2466 if (!is_zero_cluster_top_locked(bs, sector_num) ||
2467 (cl_end > 0 && !is_zero_cluster_top_locked(bs, cl_end))) {
2468 qemu_co_mutex_unlock(&s->lock);
2469 return -ENOTSUP;
2470 }
2471 } else {
2472 qemu_co_mutex_lock(&s->lock);
2473 }
2474
2475 /* Whatever is left can use real zero clusters */
2476 ret = qcow2_zero_clusters(bs, sector_num << BDRV_SECTOR_BITS, nb_sectors);
2477 qemu_co_mutex_unlock(&s->lock);
2478
2479 return ret;
2480 }
2481
2482 static coroutine_fn int qcow2_co_discard(BlockDriverState *bs,
2483 int64_t sector_num, int nb_sectors)
2484 {
2485 int ret;
2486 BDRVQcow2State *s = bs->opaque;
2487
2488 qemu_co_mutex_lock(&s->lock);
2489 ret = qcow2_discard_clusters(bs, sector_num << BDRV_SECTOR_BITS,
2490 nb_sectors, QCOW2_DISCARD_REQUEST, false);
2491 qemu_co_mutex_unlock(&s->lock);
2492 return ret;
2493 }
2494
2495 static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
2496 {
2497 BDRVQcow2State *s = bs->opaque;
2498 int64_t new_l1_size;
2499 int ret;
2500
2501 if (offset & 511) {
2502 error_report("The new size must be a multiple of 512");
2503 return -EINVAL;
2504 }
2505
2506 /* cannot proceed if image has snapshots */
2507 if (s->nb_snapshots) {
2508 error_report("Can't resize an image which has snapshots");
2509 return -ENOTSUP;
2510 }
2511
2512 /* shrinking is currently not supported */
2513 if (offset < bs->total_sectors * 512) {
2514 error_report("qcow2 doesn't support shrinking images yet");
2515 return -ENOTSUP;
2516 }
2517
2518 new_l1_size = size_to_l1(s, offset);
2519 ret = qcow2_grow_l1_table(bs, new_l1_size, true);
2520 if (ret < 0) {
2521 return ret;
2522 }
2523
2524 /* write updated header.size */
2525 offset = cpu_to_be64(offset);
2526 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, size),
2527 &offset, sizeof(uint64_t));
2528 if (ret < 0) {
2529 return ret;
2530 }
2531
2532 s->l1_vm_state_index = new_l1_size;
2533 return 0;
2534 }
2535
2536 /* XXX: put compressed sectors first, then all the cluster aligned
2537 tables to avoid losing bytes in alignment */
2538 static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
2539 const uint8_t *buf, int nb_sectors)
2540 {
2541 BDRVQcow2State *s = bs->opaque;
2542 z_stream strm;
2543 int ret, out_len;
2544 uint8_t *out_buf;
2545 uint64_t cluster_offset;
2546
2547 if (nb_sectors == 0) {
2548 /* align end of file to a sector boundary to ease reading with
2549 sector based I/Os */
2550 cluster_offset = bdrv_getlength(bs->file->bs);
2551 return bdrv_truncate(bs->file->bs, cluster_offset);
2552 }
2553
2554 if (nb_sectors != s->cluster_sectors) {
2555 ret = -EINVAL;
2556
2557 /* Zero-pad last write if image size is not cluster aligned */
2558 if (sector_num + nb_sectors == bs->total_sectors &&
2559 nb_sectors < s->cluster_sectors) {
2560 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
2561 memset(pad_buf, 0, s->cluster_size);
2562 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
2563 ret = qcow2_write_compressed(bs, sector_num,
2564 pad_buf, s->cluster_sectors);
2565 qemu_vfree(pad_buf);
2566 }
2567 return ret;
2568 }
2569
2570 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
2571
2572 /* best compression, small window, no zlib header */
2573 memset(&strm, 0, sizeof(strm));
2574 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
2575 Z_DEFLATED, -12,
2576 9, Z_DEFAULT_STRATEGY);
2577 if (ret != 0) {
2578 ret = -EINVAL;
2579 goto fail;
2580 }
2581
2582 strm.avail_in = s->cluster_size;
2583 strm.next_in = (uint8_t *)buf;
2584 strm.avail_out = s->cluster_size;
2585 strm.next_out = out_buf;
2586
2587 ret = deflate(&strm, Z_FINISH);
2588 if (ret != Z_STREAM_END && ret != Z_OK) {
2589 deflateEnd(&strm);
2590 ret = -EINVAL;
2591 goto fail;
2592 }
2593 out_len = strm.next_out - out_buf;
2594
2595 deflateEnd(&strm);
2596
2597 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
2598 /* could not compress: write normal cluster */
2599 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
2600 if (ret < 0) {
2601 goto fail;
2602 }
2603 } else {
2604 cluster_offset = qcow2_alloc_compressed_cluster_offset(bs,
2605 sector_num << 9, out_len);
2606 if (!cluster_offset) {
2607 ret = -EIO;
2608 goto fail;
2609 }
2610 cluster_offset &= s->cluster_offset_mask;
2611
2612 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
2613 if (ret < 0) {
2614 goto fail;
2615 }
2616
2617 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
2618 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len);
2619 if (ret < 0) {
2620 goto fail;
2621 }
2622 }
2623
2624 ret = 0;
2625 fail:
2626 g_free(out_buf);
2627 return ret;
2628 }
2629
2630 static int make_completely_empty(BlockDriverState *bs)
2631 {
2632 BDRVQcow2State *s = bs->opaque;
2633 int ret, l1_clusters;
2634 int64_t offset;
2635 uint64_t *new_reftable = NULL;
2636 uint64_t rt_entry, l1_size2;
2637 struct {
2638 uint64_t l1_offset;
2639 uint64_t reftable_offset;
2640 uint32_t reftable_clusters;
2641 } QEMU_PACKED l1_ofs_rt_ofs_cls;
2642
2643 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2644 if (ret < 0) {
2645 goto fail;
2646 }
2647
2648 ret = qcow2_cache_empty(bs, s->refcount_block_cache);
2649 if (ret < 0) {
2650 goto fail;
2651 }
2652
2653 /* Refcounts will be broken utterly */
2654 ret = qcow2_mark_dirty(bs);
2655 if (ret < 0) {
2656 goto fail;
2657 }
2658
2659 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2660
2661 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2662 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t);
2663
2664 /* After this call, neither the in-memory nor the on-disk refcount
2665 * information accurately describe the actual references */
2666
2667 ret = bdrv_write_zeroes(bs->file->bs, s->l1_table_offset / BDRV_SECTOR_SIZE,
2668 l1_clusters * s->cluster_sectors, 0);
2669 if (ret < 0) {
2670 goto fail_broken_refcounts;
2671 }
2672 memset(s->l1_table, 0, l1_size2);
2673
2674 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
2675
2676 /* Overwrite enough clusters at the beginning of the sectors to place
2677 * the refcount table, a refcount block and the L1 table in; this may
2678 * overwrite parts of the existing refcount and L1 table, which is not
2679 * an issue because the dirty flag is set, complete data loss is in fact
2680 * desired and partial data loss is consequently fine as well */
2681 ret = bdrv_write_zeroes(bs->file->bs, s->cluster_size / BDRV_SECTOR_SIZE,
2682 (2 + l1_clusters) * s->cluster_size /
2683 BDRV_SECTOR_SIZE, 0);
2684 /* This call (even if it failed overall) may have overwritten on-disk
2685 * refcount structures; in that case, the in-memory refcount information
2686 * will probably differ from the on-disk information which makes the BDS
2687 * unusable */
2688 if (ret < 0) {
2689 goto fail_broken_refcounts;
2690 }
2691
2692 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2693 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
2694
2695 /* "Create" an empty reftable (one cluster) directly after the image
2696 * header and an empty L1 table three clusters after the image header;
2697 * the cluster between those two will be used as the first refblock */
2698 cpu_to_be64w(&l1_ofs_rt_ofs_cls.l1_offset, 3 * s->cluster_size);
2699 cpu_to_be64w(&l1_ofs_rt_ofs_cls.reftable_offset, s->cluster_size);
2700 cpu_to_be32w(&l1_ofs_rt_ofs_cls.reftable_clusters, 1);
2701 ret = bdrv_pwrite_sync(bs->file->bs, offsetof(QCowHeader, l1_table_offset),
2702 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
2703 if (ret < 0) {
2704 goto fail_broken_refcounts;
2705 }
2706
2707 s->l1_table_offset = 3 * s->cluster_size;
2708
2709 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t));
2710 if (!new_reftable) {
2711 ret = -ENOMEM;
2712 goto fail_broken_refcounts;
2713 }
2714
2715 s->refcount_table_offset = s->cluster_size;
2716 s->refcount_table_size = s->cluster_size / sizeof(uint64_t);
2717
2718 g_free(s->refcount_table);
2719 s->refcount_table = new_reftable;
2720 new_reftable = NULL;
2721
2722 /* Now the in-memory refcount information again corresponds to the on-disk
2723 * information (reftable is empty and no refblocks (the refblock cache is
2724 * empty)); however, this means some clusters (e.g. the image header) are
2725 * referenced, but not refcounted, but the normal qcow2 code assumes that
2726 * the in-memory information is always correct */
2727
2728 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
2729
2730 /* Enter the first refblock into the reftable */
2731 rt_entry = cpu_to_be64(2 * s->cluster_size);
2732 ret = bdrv_pwrite_sync(bs->file->bs, s->cluster_size,
2733 &rt_entry, sizeof(rt_entry));
2734 if (ret < 0) {
2735 goto fail_broken_refcounts;
2736 }
2737 s->refcount_table[0] = 2 * s->cluster_size;
2738
2739 s->free_cluster_index = 0;
2740 assert(3 + l1_clusters <= s->refcount_block_size);
2741 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
2742 if (offset < 0) {
2743 ret = offset;
2744 goto fail_broken_refcounts;
2745 } else if (offset > 0) {
2746 error_report("First cluster in emptied image is in use");
2747 abort();
2748 }
2749
2750 /* Now finally the in-memory information corresponds to the on-disk
2751 * structures and is correct */
2752 ret = qcow2_mark_clean(bs);
2753 if (ret < 0) {
2754 goto fail;
2755 }
2756
2757 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size);
2758 if (ret < 0) {
2759 goto fail;
2760 }
2761
2762 return 0;
2763
2764 fail_broken_refcounts:
2765 /* The BDS is unusable at this point. If we wanted to make it usable, we
2766 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
2767 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
2768 * again. However, because the functions which could have caused this error
2769 * path to be taken are used by those functions as well, it's very likely
2770 * that that sequence will fail as well. Therefore, just eject the BDS. */
2771 bs->drv = NULL;
2772
2773 fail:
2774 g_free(new_reftable);
2775 return ret;
2776 }
2777
2778 static int qcow2_make_empty(BlockDriverState *bs)
2779 {
2780 BDRVQcow2State *s = bs->opaque;
2781 uint64_t start_sector;
2782 int sector_step = INT_MAX / BDRV_SECTOR_SIZE;
2783 int l1_clusters, ret = 0;
2784
2785 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2786
2787 if (s->qcow_version >= 3 && !s->snapshots &&
2788 3 + l1_clusters <= s->refcount_block_size) {
2789 /* The following function only works for qcow2 v3 images (it requires
2790 * the dirty flag) and only as long as there are no snapshots (because
2791 * it completely empties the image). Furthermore, the L1 table and three
2792 * additional clusters (image header, refcount table, one refcount
2793 * block) have to fit inside one refcount block. */
2794 return make_completely_empty(bs);
2795 }
2796
2797 /* This fallback code simply discards every active cluster; this is slow,
2798 * but works in all cases */
2799 for (start_sector = 0; start_sector < bs->total_sectors;
2800 start_sector += sector_step)
2801 {
2802 /* As this function is generally used after committing an external
2803 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
2804 * default action for this kind of discard is to pass the discard,
2805 * which will ideally result in an actually smaller image file, as
2806 * is probably desired. */
2807 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE,
2808 MIN(sector_step,
2809 bs->total_sectors - start_sector),
2810 QCOW2_DISCARD_SNAPSHOT, true);
2811 if (ret < 0) {
2812 break;
2813 }
2814 }
2815
2816 return ret;
2817 }
2818
2819 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
2820 {
2821 BDRVQcow2State *s = bs->opaque;
2822 int ret;
2823
2824 qemu_co_mutex_lock(&s->lock);
2825 ret = qcow2_cache_flush(bs, s->l2_table_cache);
2826 if (ret < 0) {
2827 qemu_co_mutex_unlock(&s->lock);
2828 return ret;
2829 }
2830
2831 if (qcow2_need_accurate_refcounts(s)) {
2832 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
2833 if (ret < 0) {
2834 qemu_co_mutex_unlock(&s->lock);
2835 return ret;
2836 }
2837 }
2838 qemu_co_mutex_unlock(&s->lock);
2839
2840 return 0;
2841 }
2842
2843 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2844 {
2845 BDRVQcow2State *s = bs->opaque;
2846 bdi->unallocated_blocks_are_zero = true;
2847 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
2848 bdi->cluster_size = s->cluster_size;
2849 bdi->vm_state_offset = qcow2_vm_state_offset(s);
2850 return 0;
2851 }
2852
2853 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
2854 {
2855 BDRVQcow2State *s = bs->opaque;
2856 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1);
2857
2858 *spec_info = (ImageInfoSpecific){
2859 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
2860 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1),
2861 };
2862 if (s->qcow_version == 2) {
2863 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
2864 .compat = g_strdup("0.10"),
2865 .refcount_bits = s->refcount_bits,
2866 };
2867 } else if (s->qcow_version == 3) {
2868 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
2869 .compat = g_strdup("1.1"),
2870 .lazy_refcounts = s->compatible_features &
2871 QCOW2_COMPAT_LAZY_REFCOUNTS,
2872 .has_lazy_refcounts = true,
2873 .corrupt = s->incompatible_features &
2874 QCOW2_INCOMPAT_CORRUPT,
2875 .has_corrupt = true,
2876 .refcount_bits = s->refcount_bits,
2877 };
2878 } else {
2879 /* if this assertion fails, this probably means a new version was
2880 * added without having it covered here */
2881 assert(false);
2882 }
2883
2884 return spec_info;
2885 }
2886
2887 #if 0
2888 static void dump_refcounts(BlockDriverState *bs)
2889 {
2890 BDRVQcow2State *s = bs->opaque;
2891 int64_t nb_clusters, k, k1, size;
2892 int refcount;
2893
2894 size = bdrv_getlength(bs->file->bs);
2895 nb_clusters = size_to_clusters(s, size);
2896 for(k = 0; k < nb_clusters;) {
2897 k1 = k;
2898 refcount = get_refcount(bs, k);
2899 k++;
2900 while (k < nb_clusters && get_refcount(bs, k) == refcount)
2901 k++;
2902 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
2903 k - k1);
2904 }
2905 }
2906 #endif
2907
2908 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
2909 int64_t pos)
2910 {
2911 BDRVQcow2State *s = bs->opaque;
2912 int64_t total_sectors = bs->total_sectors;
2913 bool zero_beyond_eof = bs->zero_beyond_eof;
2914 int ret;
2915
2916 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
2917 bs->zero_beyond_eof = false;
2918 ret = bdrv_pwritev(bs, qcow2_vm_state_offset(s) + pos, qiov);
2919 bs->zero_beyond_eof = zero_beyond_eof;
2920
2921 /* bdrv_co_do_writev will have increased the total_sectors value to include
2922 * the VM state - the VM state is however not an actual part of the block
2923 * device, therefore, we need to restore the old value. */
2924 bs->total_sectors = total_sectors;
2925
2926 return ret;
2927 }
2928
2929 static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
2930 int64_t pos, int size)
2931 {
2932 BDRVQcow2State *s = bs->opaque;
2933 bool zero_beyond_eof = bs->zero_beyond_eof;
2934 int ret;
2935
2936 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
2937 bs->zero_beyond_eof = false;
2938 ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
2939 bs->zero_beyond_eof = zero_beyond_eof;
2940
2941 return ret;
2942 }
2943
2944 /*
2945 * Downgrades an image's version. To achieve this, any incompatible features
2946 * have to be removed.
2947 */
2948 static int qcow2_downgrade(BlockDriverState *bs, int target_version,
2949 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
2950 {
2951 BDRVQcow2State *s = bs->opaque;
2952 int current_version = s->qcow_version;
2953 int ret;
2954
2955 if (target_version == current_version) {
2956 return 0;
2957 } else if (target_version > current_version) {
2958 return -EINVAL;
2959 } else if (target_version != 2) {
2960 return -EINVAL;
2961 }
2962
2963 if (s->refcount_order != 4) {
2964 error_report("compat=0.10 requires refcount_bits=16");
2965 return -ENOTSUP;
2966 }
2967
2968 /* clear incompatible features */
2969 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
2970 ret = qcow2_mark_clean(bs);
2971 if (ret < 0) {
2972 return ret;
2973 }
2974 }
2975
2976 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
2977 * the first place; if that happens nonetheless, returning -ENOTSUP is the
2978 * best thing to do anyway */
2979
2980 if (s->incompatible_features) {
2981 return -ENOTSUP;
2982 }
2983
2984 /* since we can ignore compatible features, we can set them to 0 as well */
2985 s->compatible_features = 0;
2986 /* if lazy refcounts have been used, they have already been fixed through
2987 * clearing the dirty flag */
2988
2989 /* clearing autoclear features is trivial */
2990 s->autoclear_features = 0;
2991
2992 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
2993 if (ret < 0) {
2994 return ret;
2995 }
2996
2997 s->qcow_version = target_version;
2998 ret = qcow2_update_header(bs);
2999 if (ret < 0) {
3000 s->qcow_version = current_version;
3001 return ret;
3002 }
3003 return 0;
3004 }
3005
3006 typedef enum Qcow2AmendOperation {
3007 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
3008 * statically initialized to so that the helper CB can discern the first
3009 * invocation from an operation change */
3010 QCOW2_NO_OPERATION = 0,
3011
3012 QCOW2_CHANGING_REFCOUNT_ORDER,
3013 QCOW2_DOWNGRADING,
3014 } Qcow2AmendOperation;
3015
3016 typedef struct Qcow2AmendHelperCBInfo {
3017 /* The code coordinating the amend operations should only modify
3018 * these four fields; the rest will be managed by the CB */
3019 BlockDriverAmendStatusCB *original_status_cb;
3020 void *original_cb_opaque;
3021
3022 Qcow2AmendOperation current_operation;
3023
3024 /* Total number of operations to perform (only set once) */
3025 int total_operations;
3026
3027 /* The following fields are managed by the CB */
3028
3029 /* Number of operations completed */
3030 int operations_completed;
3031
3032 /* Cumulative offset of all completed operations */
3033 int64_t offset_completed;
3034
3035 Qcow2AmendOperation last_operation;
3036 int64_t last_work_size;
3037 } Qcow2AmendHelperCBInfo;
3038
3039 static void qcow2_amend_helper_cb(BlockDriverState *bs,
3040 int64_t operation_offset,
3041 int64_t operation_work_size, void *opaque)
3042 {
3043 Qcow2AmendHelperCBInfo *info = opaque;
3044 int64_t current_work_size;
3045 int64_t projected_work_size;
3046
3047 if (info->current_operation != info->last_operation) {
3048 if (info->last_operation != QCOW2_NO_OPERATION) {
3049 info->offset_completed += info->last_work_size;
3050 info->operations_completed++;
3051 }
3052
3053 info->last_operation = info->current_operation;
3054 }
3055
3056 assert(info->total_operations > 0);
3057 assert(info->operations_completed < info->total_operations);
3058
3059 info->last_work_size = operation_work_size;
3060
3061 current_work_size = info->offset_completed + operation_work_size;
3062
3063 /* current_work_size is the total work size for (operations_completed + 1)
3064 * operations (which includes this one), so multiply it by the number of
3065 * operations not covered and divide it by the number of operations
3066 * covered to get a projection for the operations not covered */
3067 projected_work_size = current_work_size * (info->total_operations -
3068 info->operations_completed - 1)
3069 / (info->operations_completed + 1);
3070
3071 info->original_status_cb(bs, info->offset_completed + operation_offset,
3072 current_work_size + projected_work_size,
3073 info->original_cb_opaque);
3074 }
3075
3076 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
3077 BlockDriverAmendStatusCB *status_cb,
3078 void *cb_opaque)
3079 {
3080 BDRVQcow2State *s = bs->opaque;
3081 int old_version = s->qcow_version, new_version = old_version;
3082 uint64_t new_size = 0;
3083 const char *backing_file = NULL, *backing_format = NULL;
3084 bool lazy_refcounts = s->use_lazy_refcounts;
3085 const char *compat = NULL;
3086 uint64_t cluster_size = s->cluster_size;
3087 bool encrypt;
3088 int refcount_bits = s->refcount_bits;
3089 int ret;
3090 QemuOptDesc *desc = opts->list->desc;
3091 Qcow2AmendHelperCBInfo helper_cb_info;
3092
3093 while (desc && desc->name) {
3094 if (!qemu_opt_find(opts, desc->name)) {
3095 /* only change explicitly defined options */
3096 desc++;
3097 continue;
3098 }
3099
3100 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
3101 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
3102 if (!compat) {
3103 /* preserve default */
3104 } else if (!strcmp(compat, "0.10")) {
3105 new_version = 2;
3106 } else if (!strcmp(compat, "1.1")) {
3107 new_version = 3;
3108 } else {
3109 error_report("Unknown compatibility level %s", compat);
3110 return -EINVAL;
3111 }
3112 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) {
3113 error_report("Cannot change preallocation mode");
3114 return -ENOTSUP;
3115 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
3116 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3117 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
3118 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3119 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
3120 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3121 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
3122 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
3123 !!s->cipher);
3124
3125 if (encrypt != !!s->cipher) {
3126 error_report("Changing the encryption flag is not supported");
3127 return -ENOTSUP;
3128 }
3129 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
3130 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
3131 cluster_size);
3132 if (cluster_size != s->cluster_size) {
3133 error_report("Changing the cluster size is not supported");
3134 return -ENOTSUP;
3135 }
3136 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
3137 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
3138 lazy_refcounts);
3139 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
3140 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS,
3141 refcount_bits);
3142
3143 if (refcount_bits <= 0 || refcount_bits > 64 ||
3144 !is_power_of_2(refcount_bits))
3145 {
3146 error_report("Refcount width must be a power of two and may "
3147 "not exceed 64 bits");
3148 return -EINVAL;
3149 }
3150 } else {
3151 /* if this point is reached, this probably means a new option was
3152 * added without having it covered here */
3153 abort();
3154 }
3155
3156 desc++;
3157 }
3158
3159 helper_cb_info = (Qcow2AmendHelperCBInfo){
3160 .original_status_cb = status_cb,
3161 .original_cb_opaque = cb_opaque,
3162 .total_operations = (new_version < old_version)
3163 + (s->refcount_bits != refcount_bits)
3164 };
3165
3166 /* Upgrade first (some features may require compat=1.1) */
3167 if (new_version > old_version) {
3168 s->qcow_version = new_version;
3169 ret = qcow2_update_header(bs);
3170 if (ret < 0) {
3171 s->qcow_version = old_version;
3172 return ret;
3173 }
3174 }
3175
3176 if (s->refcount_bits != refcount_bits) {
3177 int refcount_order = ctz32(refcount_bits);
3178 Error *local_error = NULL;
3179
3180 if (new_version < 3 && refcount_bits != 16) {
3181 error_report("Different refcount widths than 16 bits require "
3182 "compatibility level 1.1 or above (use compat=1.1 or "
3183 "greater)");
3184 return -EINVAL;
3185 }
3186
3187 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER;
3188 ret = qcow2_change_refcount_order(bs, refcount_order,
3189 &qcow2_amend_helper_cb,
3190 &helper_cb_info, &local_error);
3191 if (ret < 0) {
3192 error_report_err(local_error);
3193 return ret;
3194 }
3195 }
3196
3197 if (backing_file || backing_format) {
3198 ret = qcow2_change_backing_file(bs,
3199 backing_file ?: s->image_backing_file,
3200 backing_format ?: s->image_backing_format);
3201 if (ret < 0) {
3202 return ret;
3203 }
3204 }
3205
3206 if (s->use_lazy_refcounts != lazy_refcounts) {
3207 if (lazy_refcounts) {
3208 if (new_version < 3) {
3209 error_report("Lazy refcounts only supported with compatibility "
3210 "level 1.1 and above (use compat=1.1 or greater)");
3211 return -EINVAL;
3212 }
3213 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3214 ret = qcow2_update_header(bs);
3215 if (ret < 0) {
3216 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3217 return ret;
3218 }
3219 s->use_lazy_refcounts = true;
3220 } else {
3221 /* make image clean first */
3222 ret = qcow2_mark_clean(bs);
3223 if (ret < 0) {
3224 return ret;
3225 }
3226 /* now disallow lazy refcounts */
3227 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3228 ret = qcow2_update_header(bs);
3229 if (ret < 0) {
3230 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3231 return ret;
3232 }
3233 s->use_lazy_refcounts = false;
3234 }
3235 }
3236
3237 if (new_size) {
3238 ret = bdrv_truncate(bs, new_size);
3239 if (ret < 0) {
3240 return ret;
3241 }
3242 }
3243
3244 /* Downgrade last (so unsupported features can be removed before) */
3245 if (new_version < old_version) {
3246 helper_cb_info.current_operation = QCOW2_DOWNGRADING;
3247 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb,
3248 &helper_cb_info);
3249 if (ret < 0) {
3250 return ret;
3251 }
3252 }
3253
3254 return 0;
3255 }
3256
3257 /*
3258 * If offset or size are negative, respectively, they will not be included in
3259 * the BLOCK_IMAGE_CORRUPTED event emitted.
3260 * fatal will be ignored for read-only BDS; corruptions found there will always
3261 * be considered non-fatal.
3262 */
3263 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
3264 int64_t size, const char *message_format, ...)
3265 {
3266 BDRVQcow2State *s = bs->opaque;
3267 const char *node_name;
3268 char *message;
3269 va_list ap;
3270
3271 fatal = fatal && !bs->read_only;
3272
3273 if (s->signaled_corruption &&
3274 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
3275 {
3276 return;
3277 }
3278
3279 va_start(ap, message_format);
3280 message = g_strdup_vprintf(message_format, ap);
3281 va_end(ap);
3282
3283 if (fatal) {
3284 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
3285 "corruption events will be suppressed\n", message);
3286 } else {
3287 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
3288 "corruption events will be suppressed\n", message);
3289 }
3290
3291 node_name = bdrv_get_node_name(bs);
3292 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
3293 *node_name != '\0', node_name,
3294 message, offset >= 0, offset,
3295 size >= 0, size,
3296 fatal, &error_abort);
3297 g_free(message);
3298
3299 if (fatal) {
3300 qcow2_mark_corrupt(bs);
3301 bs->drv = NULL; /* make BDS unusable */
3302 }
3303
3304 s->signaled_corruption = true;
3305 }
3306
3307 static QemuOptsList qcow2_create_opts = {
3308 .name = "qcow2-create-opts",
3309 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
3310 .desc = {
3311 {
3312 .name = BLOCK_OPT_SIZE,
3313 .type = QEMU_OPT_SIZE,
3314 .help = "Virtual disk size"
3315 },
3316 {
3317 .name = BLOCK_OPT_COMPAT_LEVEL,
3318 .type = QEMU_OPT_STRING,
3319 .help = "Compatibility level (0.10 or 1.1)"
3320 },
3321 {
3322 .name = BLOCK_OPT_BACKING_FILE,
3323 .type = QEMU_OPT_STRING,
3324 .help = "File name of a base image"
3325 },
3326 {
3327 .name = BLOCK_OPT_BACKING_FMT,
3328 .type = QEMU_OPT_STRING,
3329 .help = "Image format of the base image"
3330 },
3331 {
3332 .name = BLOCK_OPT_ENCRYPT,
3333 .type = QEMU_OPT_BOOL,
3334 .help = "Encrypt the image",
3335 .def_value_str = "off"
3336 },
3337 {
3338 .name = BLOCK_OPT_CLUSTER_SIZE,
3339 .type = QEMU_OPT_SIZE,
3340 .help = "qcow2 cluster size",
3341 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
3342 },
3343 {
3344 .name = BLOCK_OPT_PREALLOC,
3345 .type = QEMU_OPT_STRING,
3346 .help = "Preallocation mode (allowed values: off, metadata, "
3347 "falloc, full)"
3348 },
3349 {
3350 .name = BLOCK_OPT_LAZY_REFCOUNTS,
3351 .type = QEMU_OPT_BOOL,
3352 .help = "Postpone refcount updates",
3353 .def_value_str = "off"
3354 },
3355 {
3356 .name = BLOCK_OPT_REFCOUNT_BITS,
3357 .type = QEMU_OPT_NUMBER,
3358 .help = "Width of a reference count entry in bits",
3359 .def_value_str = "16"
3360 },
3361 { /* end of list */ }
3362 }
3363 };
3364
3365 BlockDriver bdrv_qcow2 = {
3366 .format_name = "qcow2",
3367 .instance_size = sizeof(BDRVQcow2State),
3368 .bdrv_probe = qcow2_probe,
3369 .bdrv_open = qcow2_open,
3370 .bdrv_close = qcow2_close,
3371 .bdrv_reopen_prepare = qcow2_reopen_prepare,
3372 .bdrv_reopen_commit = qcow2_reopen_commit,
3373 .bdrv_reopen_abort = qcow2_reopen_abort,
3374 .bdrv_join_options = qcow2_join_options,
3375 .bdrv_create = qcow2_create,
3376 .bdrv_has_zero_init = bdrv_has_zero_init_1,
3377 .bdrv_co_get_block_status = qcow2_co_get_block_status,
3378 .bdrv_set_key = qcow2_set_key,
3379
3380 .bdrv_co_readv = qcow2_co_readv,
3381 .bdrv_co_writev = qcow2_co_writev,
3382 .bdrv_co_flush_to_os = qcow2_co_flush_to_os,
3383
3384 .bdrv_co_write_zeroes = qcow2_co_write_zeroes,
3385 .bdrv_co_discard = qcow2_co_discard,
3386 .bdrv_truncate = qcow2_truncate,
3387 .bdrv_write_compressed = qcow2_write_compressed,
3388