tests: virtio-9p: rename PCI configuration test
[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, 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, 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, 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, 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, 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 #ifndef CONFIG_LINUX
672 if (r->cache_clean_interval != 0) {
673 error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL
674 " not supported on this host");
675 ret = -EINVAL;
676 goto fail;
677 }
678 #endif
679 if (r->cache_clean_interval > UINT_MAX) {
680 error_setg(errp, "Cache clean interval too big");
681 ret = -EINVAL;
682 goto fail;
683 }
684
685 /* lazy-refcounts; flush if going from enabled to disabled */
686 r->use_lazy_refcounts = qemu_opt_get_bool(opts, QCOW2_OPT_LAZY_REFCOUNTS,
687 (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS));
688 if (r->use_lazy_refcounts && s->qcow_version < 3) {
689 error_setg(errp, "Lazy refcounts require a qcow2 image with at least "
690 "qemu 1.1 compatibility level");
691 ret = -EINVAL;
692 goto fail;
693 }
694
695 if (s->use_lazy_refcounts && !r->use_lazy_refcounts) {
696 ret = qcow2_mark_clean(bs);
697 if (ret < 0) {
698 error_setg_errno(errp, -ret, "Failed to disable lazy refcounts");
699 goto fail;
700 }
701 }
702
703 /* Overlap check options */
704 opt_overlap_check = qemu_opt_get(opts, QCOW2_OPT_OVERLAP);
705 opt_overlap_check_template = qemu_opt_get(opts, QCOW2_OPT_OVERLAP_TEMPLATE);
706 if (opt_overlap_check_template && opt_overlap_check &&
707 strcmp(opt_overlap_check_template, opt_overlap_check))
708 {
709 error_setg(errp, "Conflicting values for qcow2 options '"
710 QCOW2_OPT_OVERLAP "' ('%s') and '" QCOW2_OPT_OVERLAP_TEMPLATE
711 "' ('%s')", opt_overlap_check, opt_overlap_check_template);
712 ret = -EINVAL;
713 goto fail;
714 }
715 if (!opt_overlap_check) {
716 opt_overlap_check = opt_overlap_check_template ?: "cached";
717 }
718
719 if (!strcmp(opt_overlap_check, "none")) {
720 overlap_check_template = 0;
721 } else if (!strcmp(opt_overlap_check, "constant")) {
722 overlap_check_template = QCOW2_OL_CONSTANT;
723 } else if (!strcmp(opt_overlap_check, "cached")) {
724 overlap_check_template = QCOW2_OL_CACHED;
725 } else if (!strcmp(opt_overlap_check, "all")) {
726 overlap_check_template = QCOW2_OL_ALL;
727 } else {
728 error_setg(errp, "Unsupported value '%s' for qcow2 option "
729 "'overlap-check'. Allowed are any of the following: "
730 "none, constant, cached, all", opt_overlap_check);
731 ret = -EINVAL;
732 goto fail;
733 }
734
735 r->overlap_check = 0;
736 for (i = 0; i < QCOW2_OL_MAX_BITNR; i++) {
737 /* overlap-check defines a template bitmask, but every flag may be
738 * overwritten through the associated boolean option */
739 r->overlap_check |=
740 qemu_opt_get_bool(opts, overlap_bool_option_names[i],
741 overlap_check_template & (1 << i)) << i;
742 }
743
744 r->discard_passthrough[QCOW2_DISCARD_NEVER] = false;
745 r->discard_passthrough[QCOW2_DISCARD_ALWAYS] = true;
746 r->discard_passthrough[QCOW2_DISCARD_REQUEST] =
747 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_REQUEST,
748 flags & BDRV_O_UNMAP);
749 r->discard_passthrough[QCOW2_DISCARD_SNAPSHOT] =
750 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_SNAPSHOT, true);
751 r->discard_passthrough[QCOW2_DISCARD_OTHER] =
752 qemu_opt_get_bool(opts, QCOW2_OPT_DISCARD_OTHER, false);
753
754 ret = 0;
755 fail:
756 qemu_opts_del(opts);
757 opts = NULL;
758 return ret;
759 }
760
761 static void qcow2_update_options_commit(BlockDriverState *bs,
762 Qcow2ReopenState *r)
763 {
764 BDRVQcow2State *s = bs->opaque;
765 int i;
766
767 if (s->l2_table_cache) {
768 qcow2_cache_destroy(bs, s->l2_table_cache);
769 }
770 if (s->refcount_block_cache) {
771 qcow2_cache_destroy(bs, s->refcount_block_cache);
772 }
773 s->l2_table_cache = r->l2_table_cache;
774 s->refcount_block_cache = r->refcount_block_cache;
775
776 s->overlap_check = r->overlap_check;
777 s->use_lazy_refcounts = r->use_lazy_refcounts;
778
779 for (i = 0; i < QCOW2_DISCARD_MAX; i++) {
780 s->discard_passthrough[i] = r->discard_passthrough[i];
781 }
782
783 if (s->cache_clean_interval != r->cache_clean_interval) {
784 cache_clean_timer_del(bs);
785 s->cache_clean_interval = r->cache_clean_interval;
786 cache_clean_timer_init(bs, bdrv_get_aio_context(bs));
787 }
788 }
789
790 static void qcow2_update_options_abort(BlockDriverState *bs,
791 Qcow2ReopenState *r)
792 {
793 if (r->l2_table_cache) {
794 qcow2_cache_destroy(bs, r->l2_table_cache);
795 }
796 if (r->refcount_block_cache) {
797 qcow2_cache_destroy(bs, r->refcount_block_cache);
798 }
799 }
800
801 static int qcow2_update_options(BlockDriverState *bs, QDict *options,
802 int flags, Error **errp)
803 {
804 Qcow2ReopenState r = {};
805 int ret;
806
807 ret = qcow2_update_options_prepare(bs, &r, options, flags, errp);
808 if (ret >= 0) {
809 qcow2_update_options_commit(bs, &r);
810 } else {
811 qcow2_update_options_abort(bs, &r);
812 }
813
814 return ret;
815 }
816
817 static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
818 Error **errp)
819 {
820 BDRVQcow2State *s = bs->opaque;
821 unsigned int len, i;
822 int ret = 0;
823 QCowHeader header;
824 Error *local_err = NULL;
825 uint64_t ext_end;
826 uint64_t l1_vm_state_index;
827
828 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
829 if (ret < 0) {
830 error_setg_errno(errp, -ret, "Could not read qcow2 header");
831 goto fail;
832 }
833 be32_to_cpus(&header.magic);
834 be32_to_cpus(&header.version);
835 be64_to_cpus(&header.backing_file_offset);
836 be32_to_cpus(&header.backing_file_size);
837 be64_to_cpus(&header.size);
838 be32_to_cpus(&header.cluster_bits);
839 be32_to_cpus(&header.crypt_method);
840 be64_to_cpus(&header.l1_table_offset);
841 be32_to_cpus(&header.l1_size);
842 be64_to_cpus(&header.refcount_table_offset);
843 be32_to_cpus(&header.refcount_table_clusters);
844 be64_to_cpus(&header.snapshots_offset);
845 be32_to_cpus(&header.nb_snapshots);
846
847 if (header.magic != QCOW_MAGIC) {
848 error_setg(errp, "Image is not in qcow2 format");
849 ret = -EINVAL;
850 goto fail;
851 }
852 if (header.version < 2 || header.version > 3) {
853 error_setg(errp, "Unsupported qcow2 version %" PRIu32, header.version);
854 ret = -ENOTSUP;
855 goto fail;
856 }
857
858 s->qcow_version = header.version;
859
860 /* Initialise cluster size */
861 if (header.cluster_bits < MIN_CLUSTER_BITS ||
862 header.cluster_bits > MAX_CLUSTER_BITS) {
863 error_setg(errp, "Unsupported cluster size: 2^%" PRIu32,
864 header.cluster_bits);
865 ret = -EINVAL;
866 goto fail;
867 }
868
869 s->cluster_bits = header.cluster_bits;
870 s->cluster_size = 1 << s->cluster_bits;
871 s->cluster_sectors = 1 << (s->cluster_bits - 9);
872
873 /* Initialise version 3 header fields */
874 if (header.version == 2) {
875 header.incompatible_features = 0;
876 header.compatible_features = 0;
877 header.autoclear_features = 0;
878 header.refcount_order = 4;
879 header.header_length = 72;
880 } else {
881 be64_to_cpus(&header.incompatible_features);
882 be64_to_cpus(&header.compatible_features);
883 be64_to_cpus(&header.autoclear_features);
884 be32_to_cpus(&header.refcount_order);
885 be32_to_cpus(&header.header_length);
886
887 if (header.header_length < 104) {
888 error_setg(errp, "qcow2 header too short");
889 ret = -EINVAL;
890 goto fail;
891 }
892 }
893
894 if (header.header_length > s->cluster_size) {
895 error_setg(errp, "qcow2 header exceeds cluster size");
896 ret = -EINVAL;
897 goto fail;
898 }
899
900 if (header.header_length > sizeof(header)) {
901 s->unknown_header_fields_size = header.header_length - sizeof(header);
902 s->unknown_header_fields = g_malloc(s->unknown_header_fields_size);
903 ret = bdrv_pread(bs->file, sizeof(header), s->unknown_header_fields,
904 s->unknown_header_fields_size);
905 if (ret < 0) {
906 error_setg_errno(errp, -ret, "Could not read unknown qcow2 header "
907 "fields");
908 goto fail;
909 }
910 }
911
912 if (header.backing_file_offset > s->cluster_size) {
913 error_setg(errp, "Invalid backing file offset");
914 ret = -EINVAL;
915 goto fail;
916 }
917
918 if (header.backing_file_offset) {
919 ext_end = header.backing_file_offset;
920 } else {
921 ext_end = 1 << header.cluster_bits;
922 }
923
924 /* Handle feature bits */
925 s->incompatible_features = header.incompatible_features;
926 s->compatible_features = header.compatible_features;
927 s->autoclear_features = header.autoclear_features;
928
929 if (s->incompatible_features & ~QCOW2_INCOMPAT_MASK) {
930 void *feature_table = NULL;
931 qcow2_read_extensions(bs, header.header_length, ext_end,
932 &feature_table, NULL);
933 report_unsupported_feature(errp, feature_table,
934 s->incompatible_features &
935 ~QCOW2_INCOMPAT_MASK);
936 ret = -ENOTSUP;
937 g_free(feature_table);
938 goto fail;
939 }
940
941 if (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT) {
942 /* Corrupt images may not be written to unless they are being repaired
943 */
944 if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
945 error_setg(errp, "qcow2: Image is corrupt; cannot be opened "
946 "read/write");
947 ret = -EACCES;
948 goto fail;
949 }
950 }
951
952 /* Check support for various header values */
953 if (header.refcount_order > 6) {
954 error_setg(errp, "Reference count entry width too large; may not "
955 "exceed 64 bits");
956 ret = -EINVAL;
957 goto fail;
958 }
959 s->refcount_order = header.refcount_order;
960 s->refcount_bits = 1 << s->refcount_order;
961 s->refcount_max = UINT64_C(1) << (s->refcount_bits - 1);
962 s->refcount_max += s->refcount_max - 1;
963
964 if (header.crypt_method > QCOW_CRYPT_AES) {
965 error_setg(errp, "Unsupported encryption method: %" PRIu32,
966 header.crypt_method);
967 ret = -EINVAL;
968 goto fail;
969 }
970 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128,
971 QCRYPTO_CIPHER_MODE_CBC)) {
972 error_setg(errp, "AES cipher not available");
973 ret = -EINVAL;
974 goto fail;
975 }
976 s->crypt_method_header = header.crypt_method;
977 if (s->crypt_method_header) {
978 if (bdrv_uses_whitelist() &&
979 s->crypt_method_header == QCOW_CRYPT_AES) {
980 error_setg(errp,
981 "Use of AES-CBC encrypted qcow2 images is no longer "
982 "supported in system emulators");
983 error_append_hint(errp,
984 "You can use 'qemu-img convert' to convert your "
985 "image to an alternative supported format, such "
986 "as unencrypted qcow2, or raw with the LUKS "
987 "format instead.\n");
988 ret = -ENOSYS;
989 goto fail;
990 }
991
992 bs->encrypted = true;
993 }
994
995 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
996 s->l2_size = 1 << s->l2_bits;
997 /* 2^(s->refcount_order - 3) is the refcount width in bytes */
998 s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
999 s->refcount_block_size = 1 << s->refcount_block_bits;
1000 bs->total_sectors = header.size / 512;
1001 s->csize_shift = (62 - (s->cluster_bits - 8));
1002 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
1003 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
1004
1005 s->refcount_table_offset = header.refcount_table_offset;
1006 s->refcount_table_size =
1007 header.refcount_table_clusters << (s->cluster_bits - 3);
1008
1009 if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) {
1010 error_setg(errp, "Reference count table too large");
1011 ret = -EINVAL;
1012 goto fail;
1013 }
1014
1015 ret = validate_table_offset(bs, s->refcount_table_offset,
1016 s->refcount_table_size, sizeof(uint64_t));
1017 if (ret < 0) {
1018 error_setg(errp, "Invalid reference count table offset");
1019 goto fail;
1020 }
1021
1022 /* Snapshot table offset/length */
1023 if (header.nb_snapshots > QCOW_MAX_SNAPSHOTS) {
1024 error_setg(errp, "Too many snapshots");
1025 ret = -EINVAL;
1026 goto fail;
1027 }
1028
1029 ret = validate_table_offset(bs, header.snapshots_offset,
1030 header.nb_snapshots,
1031 sizeof(QCowSnapshotHeader));
1032 if (ret < 0) {
1033 error_setg(errp, "Invalid snapshot table offset");
1034 goto fail;
1035 }
1036
1037 /* read the level 1 table */
1038 if (header.l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
1039 error_setg(errp, "Active L1 table too large");
1040 ret = -EFBIG;
1041 goto fail;
1042 }
1043 s->l1_size = header.l1_size;
1044
1045 l1_vm_state_index = size_to_l1(s, header.size);
1046 if (l1_vm_state_index > INT_MAX) {
1047 error_setg(errp, "Image is too big");
1048 ret = -EFBIG;
1049 goto fail;
1050 }
1051 s->l1_vm_state_index = l1_vm_state_index;
1052
1053 /* the L1 table must contain at least enough entries to put
1054 header.size bytes */
1055 if (s->l1_size < s->l1_vm_state_index) {
1056 error_setg(errp, "L1 table is too small");
1057 ret = -EINVAL;
1058 goto fail;
1059 }
1060
1061 ret = validate_table_offset(bs, header.l1_table_offset,
1062 header.l1_size, sizeof(uint64_t));
1063 if (ret < 0) {
1064 error_setg(errp, "Invalid L1 table offset");
1065 goto fail;
1066 }
1067 s->l1_table_offset = header.l1_table_offset;
1068
1069
1070 if (s->l1_size > 0) {
1071 s->l1_table = qemu_try_blockalign(bs->file->bs,
1072 align_offset(s->l1_size * sizeof(uint64_t), 512));
1073 if (s->l1_table == NULL) {
1074 error_setg(errp, "Could not allocate L1 table");
1075 ret = -ENOMEM;
1076 goto fail;
1077 }
1078 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
1079 s->l1_size * sizeof(uint64_t));
1080 if (ret < 0) {
1081 error_setg_errno(errp, -ret, "Could not read L1 table");
1082 goto fail;
1083 }
1084 for(i = 0;i < s->l1_size; i++) {
1085 be64_to_cpus(&s->l1_table[i]);
1086 }
1087 }
1088
1089 /* Parse driver-specific options */
1090 ret = qcow2_update_options(bs, options, flags, errp);
1091 if (ret < 0) {
1092 goto fail;
1093 }
1094
1095 s->cluster_cache = g_malloc(s->cluster_size);
1096 /* one more sector for decompressed data alignment */
1097 s->cluster_data = qemu_try_blockalign(bs->file->bs, QCOW_MAX_CRYPT_CLUSTERS
1098 * s->cluster_size + 512);
1099 if (s->cluster_data == NULL) {
1100 error_setg(errp, "Could not allocate temporary cluster buffer");
1101 ret = -ENOMEM;
1102 goto fail;
1103 }
1104
1105 s->cluster_cache_offset = -1;
1106 s->flags = flags;
1107
1108 ret = qcow2_refcount_init(bs);
1109 if (ret != 0) {
1110 error_setg_errno(errp, -ret, "Could not initialize refcount handling");
1111 goto fail;
1112 }
1113
1114 QLIST_INIT(&s->cluster_allocs);
1115 QTAILQ_INIT(&s->discards);
1116
1117 /* read qcow2 extensions */
1118 if (qcow2_read_extensions(bs, header.header_length, ext_end, NULL,
1119 &local_err)) {
1120 error_propagate(errp, local_err);
1121 ret = -EINVAL;
1122 goto fail;
1123 }
1124
1125 /* read the backing file name */
1126 if (header.backing_file_offset != 0) {
1127 len = header.backing_file_size;
1128 if (len > MIN(1023, s->cluster_size - header.backing_file_offset) ||
1129 len >= sizeof(bs->backing_file)) {
1130 error_setg(errp, "Backing file name too long");
1131 ret = -EINVAL;
1132 goto fail;
1133 }
1134 ret = bdrv_pread(bs->file, header.backing_file_offset,
1135 bs->backing_file, len);
1136 if (ret < 0) {
1137 error_setg_errno(errp, -ret, "Could not read backing file name");
1138 goto fail;
1139 }
1140 bs->backing_file[len] = '\0';
1141 s->image_backing_file = g_strdup(bs->backing_file);
1142 }
1143
1144 /* Internal snapshots */
1145 s->snapshots_offset = header.snapshots_offset;
1146 s->nb_snapshots = header.nb_snapshots;
1147
1148 ret = qcow2_read_snapshots(bs);
1149 if (ret < 0) {
1150 error_setg_errno(errp, -ret, "Could not read snapshots");
1151 goto fail;
1152 }
1153
1154 /* Clear unknown autoclear feature bits */
1155 if (!bs->read_only && !(flags & BDRV_O_INACTIVE) && s->autoclear_features) {
1156 s->autoclear_features = 0;
1157 ret = qcow2_update_header(bs);
1158 if (ret < 0) {
1159 error_setg_errno(errp, -ret, "Could not update qcow2 header");
1160 goto fail;
1161 }
1162 }
1163
1164 /* Initialise locks */
1165 qemu_co_mutex_init(&s->lock);
1166 bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
1167
1168 /* Repair image if dirty */
1169 if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
1170 (s->incompatible_features & QCOW2_INCOMPAT_DIRTY)) {
1171 BdrvCheckResult result = {0};
1172
1173 ret = qcow2_check(bs, &result, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
1174 if (ret < 0) {
1175 error_setg_errno(errp, -ret, "Could not repair dirty image");
1176 goto fail;
1177 }
1178 }
1179
1180 #ifdef DEBUG_ALLOC
1181 {
1182 BdrvCheckResult result = {0};
1183 qcow2_check_refcounts(bs, &result, 0);
1184 }
1185 #endif
1186 return ret;
1187
1188 fail:
1189 g_free(s->unknown_header_fields);
1190 cleanup_unknown_header_ext(bs);
1191 qcow2_free_snapshots(bs);
1192 qcow2_refcount_close(bs);
1193 qemu_vfree(s->l1_table);
1194 /* else pre-write overlap checks in cache_destroy may crash */
1195 s->l1_table = NULL;
1196 cache_clean_timer_del(bs);
1197 if (s->l2_table_cache) {
1198 qcow2_cache_destroy(bs, s->l2_table_cache);
1199 }
1200 if (s->refcount_block_cache) {
1201 qcow2_cache_destroy(bs, s->refcount_block_cache);
1202 }
1203 g_free(s->cluster_cache);
1204 qemu_vfree(s->cluster_data);
1205 return ret;
1206 }
1207
1208 static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp)
1209 {
1210 BDRVQcow2State *s = bs->opaque;
1211
1212 if (bs->encrypted) {
1213 /* Encryption works on a sector granularity */
1214 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
1215 }
1216 bs->bl.pwrite_zeroes_alignment = s->cluster_size;
1217 bs->bl.pdiscard_alignment = s->cluster_size;
1218 }
1219
1220 static int qcow2_set_key(BlockDriverState *bs, const char *key)
1221 {
1222 BDRVQcow2State *s = bs->opaque;
1223 uint8_t keybuf[16];
1224 int len, i;
1225 Error *err = NULL;
1226
1227 memset(keybuf, 0, 16);
1228 len = strlen(key);
1229 if (len > 16)
1230 len = 16;
1231 /* XXX: we could compress the chars to 7 bits to increase
1232 entropy */
1233 for(i = 0;i < len;i++) {
1234 keybuf[i] = key[i];
1235 }
1236 assert(bs->encrypted);
1237
1238 qcrypto_cipher_free(s->cipher);
1239 s->cipher = qcrypto_cipher_new(
1240 QCRYPTO_CIPHER_ALG_AES_128,
1241 QCRYPTO_CIPHER_MODE_CBC,
1242 keybuf, G_N_ELEMENTS(keybuf),
1243 &err);
1244
1245 if (!s->cipher) {
1246 /* XXX would be nice if errors in this method could
1247 * be properly propagate to the caller. Would need
1248 * the bdrv_set_key() API signature to be fixed. */
1249 error_free(err);
1250 return -1;
1251 }
1252 return 0;
1253 }
1254
1255 static int qcow2_reopen_prepare(BDRVReopenState *state,
1256 BlockReopenQueue *queue, Error **errp)
1257 {
1258 Qcow2ReopenState *r;
1259 int ret;
1260
1261 r = g_new0(Qcow2ReopenState, 1);
1262 state->opaque = r;
1263
1264 ret = qcow2_update_options_prepare(state->bs, r, state->options,
1265 state->flags, errp);
1266 if (ret < 0) {
1267 goto fail;
1268 }
1269
1270 /* We need to write out any unwritten data if we reopen read-only. */
1271 if ((state->flags & BDRV_O_RDWR) == 0) {
1272 ret = bdrv_flush(state->bs);
1273 if (ret < 0) {
1274 goto fail;
1275 }
1276
1277 ret = qcow2_mark_clean(state->bs);
1278 if (ret < 0) {
1279 goto fail;
1280 }
1281 }
1282
1283 return 0;
1284
1285 fail:
1286 qcow2_update_options_abort(state->bs, r);
1287 g_free(r);
1288 return ret;
1289 }
1290
1291 static void qcow2_reopen_commit(BDRVReopenState *state)
1292 {
1293 qcow2_update_options_commit(state->bs, state->opaque);
1294 g_free(state->opaque);
1295 }
1296
1297 static void qcow2_reopen_abort(BDRVReopenState *state)
1298 {
1299 qcow2_update_options_abort(state->bs, state->opaque);
1300 g_free(state->opaque);
1301 }
1302
1303 static void qcow2_join_options(QDict *options, QDict *old_options)
1304 {
1305 bool has_new_overlap_template =
1306 qdict_haskey(options, QCOW2_OPT_OVERLAP) ||
1307 qdict_haskey(options, QCOW2_OPT_OVERLAP_TEMPLATE);
1308 bool has_new_total_cache_size =
1309 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE);
1310 bool has_all_cache_options;
1311
1312 /* New overlap template overrides all old overlap options */
1313 if (has_new_overlap_template) {
1314 qdict_del(old_options, QCOW2_OPT_OVERLAP);
1315 qdict_del(old_options, QCOW2_OPT_OVERLAP_TEMPLATE);
1316 qdict_del(old_options, QCOW2_OPT_OVERLAP_MAIN_HEADER);
1317 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L1);
1318 qdict_del(old_options, QCOW2_OPT_OVERLAP_ACTIVE_L2);
1319 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_TABLE);
1320 qdict_del(old_options, QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK);
1321 qdict_del(old_options, QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE);
1322 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L1);
1323 qdict_del(old_options, QCOW2_OPT_OVERLAP_INACTIVE_L2);
1324 }
1325
1326 /* New total cache size overrides all old options */
1327 if (qdict_haskey(options, QCOW2_OPT_CACHE_SIZE)) {
1328 qdict_del(old_options, QCOW2_OPT_L2_CACHE_SIZE);
1329 qdict_del(old_options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1330 }
1331
1332 qdict_join(options, old_options, false);
1333
1334 /*
1335 * If after merging all cache size options are set, an old total size is
1336 * overwritten. Do keep all options, however, if all three are new. The
1337 * resulting error message is what we want to happen.
1338 */
1339 has_all_cache_options =
1340 qdict_haskey(options, QCOW2_OPT_CACHE_SIZE) ||
1341 qdict_haskey(options, QCOW2_OPT_L2_CACHE_SIZE) ||
1342 qdict_haskey(options, QCOW2_OPT_REFCOUNT_CACHE_SIZE);
1343
1344 if (has_all_cache_options && !has_new_total_cache_size) {
1345 qdict_del(options, QCOW2_OPT_CACHE_SIZE);
1346 }
1347 }
1348
1349 static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
1350 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
1351 {
1352 BDRVQcow2State *s = bs->opaque;
1353 uint64_t cluster_offset;
1354 int index_in_cluster, ret;
1355 unsigned int bytes;
1356 int64_t status = 0;
1357
1358 bytes = MIN(INT_MAX, nb_sectors * BDRV_SECTOR_SIZE);
1359 qemu_co_mutex_lock(&s->lock);
1360 ret = qcow2_get_cluster_offset(bs, sector_num << 9, &bytes,
1361 &cluster_offset);
1362 qemu_co_mutex_unlock(&s->lock);
1363 if (ret < 0) {
1364 return ret;
1365 }
1366
1367 *pnum = bytes >> BDRV_SECTOR_BITS;
1368
1369 if (cluster_offset != 0 && ret != QCOW2_CLUSTER_COMPRESSED &&
1370 !s->cipher) {
1371 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1372 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
1373 *file = bs->file->bs;
1374 status |= BDRV_BLOCK_OFFSET_VALID | cluster_offset;
1375 }
1376 if (ret == QCOW2_CLUSTER_ZERO) {
1377 status |= BDRV_BLOCK_ZERO;
1378 } else if (ret != QCOW2_CLUSTER_UNALLOCATED) {
1379 status |= BDRV_BLOCK_DATA;
1380 }
1381 return status;
1382 }
1383
1384 /* handle reading after the end of the backing file */
1385 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
1386 int64_t offset, int bytes)
1387 {
1388 uint64_t bs_size = bs->total_sectors * BDRV_SECTOR_SIZE;
1389 int n1;
1390
1391 if ((offset + bytes) <= bs_size) {
1392 return bytes;
1393 }
1394
1395 if (offset >= bs_size) {
1396 n1 = 0;
1397 } else {
1398 n1 = bs_size - offset;
1399 }
1400
1401 qemu_iovec_memset(qiov, n1, 0, bytes - n1);
1402
1403 return n1;
1404 }
1405
1406 static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
1407 uint64_t bytes, QEMUIOVector *qiov,
1408 int flags)
1409 {
1410 BDRVQcow2State *s = bs->opaque;
1411 int offset_in_cluster, n1;
1412 int ret;
1413 unsigned int cur_bytes; /* number of bytes in current iteration */
1414 uint64_t cluster_offset = 0;
1415 uint64_t bytes_done = 0;
1416 QEMUIOVector hd_qiov;
1417 uint8_t *cluster_data = NULL;
1418
1419 qemu_iovec_init(&hd_qiov, qiov->niov);
1420
1421 qemu_co_mutex_lock(&s->lock);
1422
1423 while (bytes != 0) {
1424
1425 /* prepare next request */
1426 cur_bytes = MIN(bytes, INT_MAX);
1427 if (s->cipher) {
1428 cur_bytes = MIN(cur_bytes,
1429 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1430 }
1431
1432 ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset);
1433 if (ret < 0) {
1434 goto fail;
1435 }
1436
1437 offset_in_cluster = offset_into_cluster(s, offset);
1438
1439 qemu_iovec_reset(&hd_qiov);
1440 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
1441
1442 switch (ret) {
1443 case QCOW2_CLUSTER_UNALLOCATED:
1444
1445 if (bs->backing) {
1446 /* read from the base image */
1447 n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov,
1448 offset, cur_bytes);
1449 if (n1 > 0) {
1450 QEMUIOVector local_qiov;
1451
1452 qemu_iovec_init(&local_qiov, hd_qiov.niov);
1453 qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1);
1454
1455 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
1456 qemu_co_mutex_unlock(&s->lock);
1457 ret = bdrv_co_preadv(bs->backing, offset, n1,
1458 &local_qiov, 0);
1459 qemu_co_mutex_lock(&s->lock);
1460
1461 qemu_iovec_destroy(&local_qiov);
1462
1463 if (ret < 0) {
1464 goto fail;
1465 }
1466 }
1467 } else {
1468 /* Note: in this case, no need to wait */
1469 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
1470 }
1471 break;
1472
1473 case QCOW2_CLUSTER_ZERO:
1474 qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
1475 break;
1476
1477 case QCOW2_CLUSTER_COMPRESSED:
1478 /* add AIO support for compressed blocks ? */
1479 ret = qcow2_decompress_cluster(bs, cluster_offset);
1480 if (ret < 0) {
1481 goto fail;
1482 }
1483
1484 qemu_iovec_from_buf(&hd_qiov, 0,
1485 s->cluster_cache + offset_in_cluster,
1486 cur_bytes);
1487 break;
1488
1489 case QCOW2_CLUSTER_NORMAL:
1490 if ((cluster_offset & 511) != 0) {
1491 ret = -EIO;
1492 goto fail;
1493 }
1494
1495 if (bs->encrypted) {
1496 assert(s->cipher);
1497
1498 /*
1499 * For encrypted images, read everything into a temporary
1500 * contiguous buffer on which the AES functions can work.
1501 */
1502 if (!cluster_data) {
1503 cluster_data =
1504 qemu_try_blockalign(bs->file->bs,
1505 QCOW_MAX_CRYPT_CLUSTERS
1506 * s->cluster_size);
1507 if (cluster_data == NULL) {
1508 ret = -ENOMEM;
1509 goto fail;
1510 }
1511 }
1512
1513 assert(cur_bytes <= QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1514 qemu_iovec_reset(&hd_qiov);
1515 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
1516 }
1517
1518 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
1519 qemu_co_mutex_unlock(&s->lock);
1520 ret = bdrv_co_preadv(bs->file,
1521 cluster_offset + offset_in_cluster,
1522 cur_bytes, &hd_qiov, 0);
1523 qemu_co_mutex_lock(&s->lock);
1524 if (ret < 0) {
1525 goto fail;
1526 }
1527 if (bs->encrypted) {
1528 assert(s->cipher);
1529 assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
1530 assert((cur_bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
1531 Error *err = NULL;
1532 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS,
1533 cluster_data, cluster_data,
1534 cur_bytes >> BDRV_SECTOR_BITS,
1535 false, &err) < 0) {
1536 error_free(err);
1537 ret = -EIO;
1538 goto fail;
1539 }
1540 qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
1541 }
1542 break;
1543
1544 default:
1545 g_assert_not_reached();
1546 ret = -EIO;
1547 goto fail;
1548 }
1549
1550 bytes -= cur_bytes;
1551 offset += cur_bytes;
1552 bytes_done += cur_bytes;
1553 }
1554 ret = 0;
1555
1556 fail:
1557 qemu_co_mutex_unlock(&s->lock);
1558
1559 qemu_iovec_destroy(&hd_qiov);
1560 qemu_vfree(cluster_data);
1561
1562 return ret;
1563 }
1564
1565 static coroutine_fn int qcow2_co_pwritev(BlockDriverState *bs, uint64_t offset,
1566 uint64_t bytes, QEMUIOVector *qiov,
1567 int flags)
1568 {
1569 BDRVQcow2State *s = bs->opaque;
1570 int offset_in_cluster;
1571 int ret;
1572 unsigned int cur_bytes; /* number of sectors in current iteration */
1573 uint64_t cluster_offset;
1574 QEMUIOVector hd_qiov;
1575 uint64_t bytes_done = 0;
1576 uint8_t *cluster_data = NULL;
1577 QCowL2Meta *l2meta = NULL;
1578
1579 trace_qcow2_writev_start_req(qemu_coroutine_self(), offset, bytes);
1580
1581 qemu_iovec_init(&hd_qiov, qiov->niov);
1582
1583 s->cluster_cache_offset = -1; /* disable compressed cache */
1584
1585 qemu_co_mutex_lock(&s->lock);
1586
1587 while (bytes != 0) {
1588
1589 l2meta = NULL;
1590
1591 trace_qcow2_writev_start_part(qemu_coroutine_self());
1592 offset_in_cluster = offset_into_cluster(s, offset);
1593 cur_bytes = MIN(bytes, INT_MAX);
1594 if (bs->encrypted) {
1595 cur_bytes = MIN(cur_bytes,
1596 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
1597 - offset_in_cluster);
1598 }
1599
1600 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
1601 &cluster_offset, &l2meta);
1602 if (ret < 0) {
1603 goto fail;
1604 }
1605
1606 assert((cluster_offset & 511) == 0);
1607
1608 qemu_iovec_reset(&hd_qiov);
1609 qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
1610
1611 if (bs->encrypted) {
1612 Error *err = NULL;
1613 assert(s->cipher);
1614 if (!cluster_data) {
1615 cluster_data = qemu_try_blockalign(bs->file->bs,
1616 QCOW_MAX_CRYPT_CLUSTERS
1617 * s->cluster_size);
1618 if (cluster_data == NULL) {
1619 ret = -ENOMEM;
1620 goto fail;
1621 }
1622 }
1623
1624 assert(hd_qiov.size <=
1625 QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
1626 qemu_iovec_to_buf(&hd_qiov, 0, cluster_data, hd_qiov.size);
1627
1628 if (qcow2_encrypt_sectors(s, offset >> BDRV_SECTOR_BITS,
1629 cluster_data, cluster_data,
1630 cur_bytes >>BDRV_SECTOR_BITS,
1631 true, &err) < 0) {
1632 error_free(err);
1633 ret = -EIO;
1634 goto fail;
1635 }
1636
1637 qemu_iovec_reset(&hd_qiov);
1638 qemu_iovec_add(&hd_qiov, cluster_data, cur_bytes);
1639 }
1640
1641 ret = qcow2_pre_write_overlap_check(bs, 0,
1642 cluster_offset + offset_in_cluster, cur_bytes);
1643 if (ret < 0) {
1644 goto fail;
1645 }
1646
1647 qemu_co_mutex_unlock(&s->lock);
1648 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
1649 trace_qcow2_writev_data(qemu_coroutine_self(),
1650 cluster_offset + offset_in_cluster);
1651 ret = bdrv_co_pwritev(bs->file,
1652 cluster_offset + offset_in_cluster,
1653 cur_bytes, &hd_qiov, 0);
1654 qemu_co_mutex_lock(&s->lock);
1655 if (ret < 0) {
1656 goto fail;
1657 }
1658
1659 while (l2meta != NULL) {
1660 QCowL2Meta *next;
1661
1662 ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
1663 if (ret < 0) {
1664 goto fail;
1665 }
1666
1667 /* Take the request off the list of running requests */
1668 if (l2meta->nb_clusters != 0) {
1669 QLIST_REMOVE(l2meta, next_in_flight);
1670 }
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 bytes -= cur_bytes;
1680 offset += cur_bytes;
1681 bytes_done += cur_bytes;
1682 trace_qcow2_writev_done_part(qemu_coroutine_self(), cur_bytes);
1683 }
1684 ret = 0;
1685
1686 fail:
1687 qemu_co_mutex_unlock(&s->lock);
1688
1689 while (l2meta != NULL) {
1690 QCowL2Meta *next;
1691
1692 if (l2meta->nb_clusters != 0) {
1693 QLIST_REMOVE(l2meta, next_in_flight);
1694 }
1695 qemu_co_queue_restart_all(&l2meta->dependent_requests);
1696
1697 next = l2meta->next;
1698 g_free(l2meta);
1699 l2meta = next;
1700 }
1701
1702 qemu_iovec_destroy(&hd_qiov);
1703 qemu_vfree(cluster_data);
1704 trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
1705
1706 return ret;
1707 }
1708
1709 static int qcow2_inactivate(BlockDriverState *bs)
1710 {
1711 BDRVQcow2State *s = bs->opaque;
1712 int ret, result = 0;
1713
1714 ret = qcow2_cache_flush(bs, s->l2_table_cache);
1715 if (ret) {
1716 result = ret;
1717 error_report("Failed to flush the L2 table cache: %s",
1718 strerror(-ret));
1719 }
1720
1721 ret = qcow2_cache_flush(bs, s->refcount_block_cache);
1722 if (ret) {
1723 result = ret;
1724 error_report("Failed to flush the refcount block cache: %s",
1725 strerror(-ret));
1726 }
1727
1728 if (result == 0) {
1729 qcow2_mark_clean(bs);
1730 }
1731
1732 return result;
1733 }
1734
1735 static void qcow2_close(BlockDriverState *bs)
1736 {
1737 BDRVQcow2State *s = bs->opaque;
1738 qemu_vfree(s->l1_table);
1739 /* else pre-write overlap checks in cache_destroy may crash */
1740 s->l1_table = NULL;
1741
1742 if (!(s->flags & BDRV_O_INACTIVE)) {
1743 qcow2_inactivate(bs);
1744 }
1745
1746 cache_clean_timer_del(bs);
1747 qcow2_cache_destroy(bs, s->l2_table_cache);
1748 qcow2_cache_destroy(bs, s->refcount_block_cache);
1749
1750 qcrypto_cipher_free(s->cipher);
1751 s->cipher = NULL;
1752
1753 g_free(s->unknown_header_fields);
1754 cleanup_unknown_header_ext(bs);
1755
1756 g_free(s->image_backing_file);
1757 g_free(s->image_backing_format);
1758
1759 g_free(s->cluster_cache);
1760 qemu_vfree(s->cluster_data);
1761 qcow2_refcount_close(bs);
1762 qcow2_free_snapshots(bs);
1763 }
1764
1765 static void qcow2_invalidate_cache(BlockDriverState *bs, Error **errp)
1766 {
1767 BDRVQcow2State *s = bs->opaque;
1768 int flags = s->flags;
1769 QCryptoCipher *cipher = NULL;
1770 QDict *options;
1771 Error *local_err = NULL;
1772 int ret;
1773
1774 /*
1775 * Backing files are read-only which makes all of their metadata immutable,
1776 * that means we don't have to worry about reopening them here.
1777 */
1778
1779 cipher = s->cipher;
1780 s->cipher = NULL;
1781
1782 qcow2_close(bs);
1783
1784 memset(s, 0, sizeof(BDRVQcow2State));
1785 options = qdict_clone_shallow(bs->options);
1786
1787 flags &= ~BDRV_O_INACTIVE;
1788 ret = qcow2_open(bs, options, flags, &local_err);
1789 QDECREF(options);
1790 if (local_err) {
1791 error_propagate(errp, local_err);
1792 error_prepend(errp, "Could not reopen qcow2 layer: ");
1793 bs->drv = NULL;
1794 return;
1795 } else if (ret < 0) {
1796 error_setg_errno(errp, -ret, "Could not reopen qcow2 layer");
1797 bs->drv = NULL;
1798 return;
1799 }
1800
1801 s->cipher = cipher;
1802 }
1803
1804 static size_t header_ext_add(char *buf, uint32_t magic, const void *s,
1805 size_t len, size_t buflen)
1806 {
1807 QCowExtension *ext_backing_fmt = (QCowExtension*) buf;
1808 size_t ext_len = sizeof(QCowExtension) + ((len + 7) & ~7);
1809
1810 if (buflen < ext_len) {
1811 return -ENOSPC;
1812 }
1813
1814 *ext_backing_fmt = (QCowExtension) {
1815 .magic = cpu_to_be32(magic),
1816 .len = cpu_to_be32(len),
1817 };
1818
1819 if (len) {
1820 memcpy(buf + sizeof(QCowExtension), s, len);
1821 }
1822
1823 return ext_len;
1824 }
1825
1826 /*
1827 * Updates the qcow2 header, including the variable length parts of it, i.e.
1828 * the backing file name and all extensions. qcow2 was not designed to allow
1829 * such changes, so if we run out of space (we can only use the first cluster)
1830 * this function may fail.
1831 *
1832 * Returns 0 on success, -errno in error cases.
1833 */
1834 int qcow2_update_header(BlockDriverState *bs)
1835 {
1836 BDRVQcow2State *s = bs->opaque;
1837 QCowHeader *header;
1838 char *buf;
1839 size_t buflen = s->cluster_size;
1840 int ret;
1841 uint64_t total_size;
1842 uint32_t refcount_table_clusters;
1843 size_t header_length;
1844 Qcow2UnknownHeaderExtension *uext;
1845
1846 buf = qemu_blockalign(bs, buflen);
1847
1848 /* Header structure */
1849 header = (QCowHeader*) buf;
1850
1851 if (buflen < sizeof(*header)) {
1852 ret = -ENOSPC;
1853 goto fail;
1854 }
1855
1856 header_length = sizeof(*header) + s->unknown_header_fields_size;
1857 total_size = bs->total_sectors * BDRV_SECTOR_SIZE;
1858 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
1859
1860 *header = (QCowHeader) {
1861 /* Version 2 fields */
1862 .magic = cpu_to_be32(QCOW_MAGIC),
1863 .version = cpu_to_be32(s->qcow_version),
1864 .backing_file_offset = 0,
1865 .backing_file_size = 0,
1866 .cluster_bits = cpu_to_be32(s->cluster_bits),
1867 .size = cpu_to_be64(total_size),
1868 .crypt_method = cpu_to_be32(s->crypt_method_header),
1869 .l1_size = cpu_to_be32(s->l1_size),
1870 .l1_table_offset = cpu_to_be64(s->l1_table_offset),
1871 .refcount_table_offset = cpu_to_be64(s->refcount_table_offset),
1872 .refcount_table_clusters = cpu_to_be32(refcount_table_clusters),
1873 .nb_snapshots = cpu_to_be32(s->nb_snapshots),
1874 .snapshots_offset = cpu_to_be64(s->snapshots_offset),
1875
1876 /* Version 3 fields */
1877 .incompatible_features = cpu_to_be64(s->incompatible_features),
1878 .compatible_features = cpu_to_be64(s->compatible_features),
1879 .autoclear_features = cpu_to_be64(s->autoclear_features),
1880 .refcount_order = cpu_to_be32(s->refcount_order),
1881 .header_length = cpu_to_be32(header_length),
1882 };
1883
1884 /* For older versions, write a shorter header */
1885 switch (s->qcow_version) {
1886 case 2:
1887 ret = offsetof(QCowHeader, incompatible_features);
1888 break;
1889 case 3:
1890 ret = sizeof(*header);
1891 break;
1892 default:
1893 ret = -EINVAL;
1894 goto fail;
1895 }
1896
1897 buf += ret;
1898 buflen -= ret;
1899 memset(buf, 0, buflen);
1900
1901 /* Preserve any unknown field in the header */
1902 if (s->unknown_header_fields_size) {
1903 if (buflen < s->unknown_header_fields_size) {
1904 ret = -ENOSPC;
1905 goto fail;
1906 }
1907
1908 memcpy(buf, s->unknown_header_fields, s->unknown_header_fields_size);
1909 buf += s->unknown_header_fields_size;
1910 buflen -= s->unknown_header_fields_size;
1911 }
1912
1913 /* Backing file format header extension */
1914 if (s->image_backing_format) {
1915 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_BACKING_FORMAT,
1916 s->image_backing_format,
1917 strlen(s->image_backing_format),
1918 buflen);
1919 if (ret < 0) {
1920 goto fail;
1921 }
1922
1923 buf += ret;
1924 buflen -= ret;
1925 }
1926
1927 /* Feature table */
1928 if (s->qcow_version >= 3) {
1929 Qcow2Feature features[] = {
1930 {
1931 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1932 .bit = QCOW2_INCOMPAT_DIRTY_BITNR,
1933 .name = "dirty bit",
1934 },
1935 {
1936 .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
1937 .bit = QCOW2_INCOMPAT_CORRUPT_BITNR,
1938 .name = "corrupt bit",
1939 },
1940 {
1941 .type = QCOW2_FEAT_TYPE_COMPATIBLE,
1942 .bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
1943 .name = "lazy refcounts",
1944 },
1945 };
1946
1947 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_FEATURE_TABLE,
1948 features, sizeof(features), buflen);
1949 if (ret < 0) {
1950 goto fail;
1951 }
1952 buf += ret;
1953 buflen -= ret;
1954 }
1955
1956 /* Keep unknown header extensions */
1957 QLIST_FOREACH(uext, &s->unknown_header_ext, next) {
1958 ret = header_ext_add(buf, uext->magic, uext->data, uext->len, buflen);
1959 if (ret < 0) {
1960 goto fail;
1961 }
1962
1963 buf += ret;
1964 buflen -= ret;
1965 }
1966
1967 /* End of header extensions */
1968 ret = header_ext_add(buf, QCOW2_EXT_MAGIC_END, NULL, 0, buflen);
1969 if (ret < 0) {
1970 goto fail;
1971 }
1972
1973 buf += ret;
1974 buflen -= ret;
1975
1976 /* Backing file name */
1977 if (s->image_backing_file) {
1978 size_t backing_file_len = strlen(s->image_backing_file);
1979
1980 if (buflen < backing_file_len) {
1981 ret = -ENOSPC;
1982 goto fail;
1983 }
1984
1985 /* Using strncpy is ok here, since buf is not NUL-terminated. */
1986 strncpy(buf, s->image_backing_file, buflen);
1987
1988 header->backing_file_offset = cpu_to_be64(buf - ((char*) header));
1989 header->backing_file_size = cpu_to_be32(backing_file_len);
1990 }
1991
1992 /* Write the new header */
1993 ret = bdrv_pwrite(bs->file, 0, header, s->cluster_size);
1994 if (ret < 0) {
1995 goto fail;
1996 }
1997
1998 ret = 0;
1999 fail:
2000 qemu_vfree(header);
2001 return ret;
2002 }
2003
2004 static int qcow2_change_backing_file(BlockDriverState *bs,
2005 const char *backing_file, const char *backing_fmt)
2006 {
2007 BDRVQcow2State *s = bs->opaque;
2008
2009 if (backing_file && strlen(backing_file) > 1023) {
2010 return -EINVAL;
2011 }
2012
2013 pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
2014 pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
2015
2016 g_free(s->image_backing_file);
2017 g_free(s->image_backing_format);
2018
2019 s->image_backing_file = backing_file ? g_strdup(bs->backing_file) : NULL;
2020 s->image_backing_format = backing_fmt ? g_strdup(bs->backing_format) : NULL;
2021
2022 return qcow2_update_header(bs);
2023 }
2024
2025 static int preallocate(BlockDriverState *bs)
2026 {
2027 uint64_t bytes;
2028 uint64_t offset;
2029 uint64_t host_offset = 0;
2030 unsigned int cur_bytes;
2031 int ret;
2032 QCowL2Meta *meta;
2033
2034 bytes = bdrv_getlength(bs);
2035 offset = 0;
2036
2037 while (bytes) {
2038 cur_bytes = MIN(bytes, INT_MAX);
2039 ret = qcow2_alloc_cluster_offset(bs, offset, &cur_bytes,
2040 &host_offset, &meta);
2041 if (ret < 0) {
2042 return ret;
2043 }
2044
2045 while (meta) {
2046 QCowL2Meta *next = meta->next;
2047
2048 ret = qcow2_alloc_cluster_link_l2(bs, meta);
2049 if (ret < 0) {
2050 qcow2_free_any_clusters(bs, meta->alloc_offset,
2051 meta->nb_clusters, QCOW2_DISCARD_NEVER);
2052 return ret;
2053 }
2054
2055 /* There are no dependent requests, but we need to remove our
2056 * request from the list of in-flight requests */
2057 QLIST_REMOVE(meta, next_in_flight);
2058
2059 g_free(meta);
2060 meta = next;
2061 }
2062
2063 /* TODO Preallocate data if requested */
2064
2065 bytes -= cur_bytes;
2066 offset += cur_bytes;
2067 }
2068
2069 /*
2070 * It is expected that the image file is large enough to actually contain
2071 * all of the allocated clusters (otherwise we get failing reads after
2072 * EOF). Extend the image to the last allocated sector.
2073 */
2074 if (host_offset != 0) {
2075 uint8_t data = 0;
2076 ret = bdrv_pwrite(bs->file, (host_offset + cur_bytes) - 1,
2077 &data, 1);
2078 if (ret < 0) {
2079 return ret;
2080 }
2081 }
2082
2083 return 0;
2084 }
2085
2086 static int qcow2_create2(const char *filename, int64_t total_size,
2087 const char *backing_file, const char *backing_format,
2088 int flags, size_t cluster_size, PreallocMode prealloc,
2089 QemuOpts *opts, int version, int refcount_order,
2090 Error **errp)
2091 {
2092 int cluster_bits;
2093 QDict *options;
2094
2095 /* Calculate cluster_bits */
2096 cluster_bits = ctz32(cluster_size);
2097 if (cluster_bits < MIN_CLUSTER_BITS || cluster_bits > MAX_CLUSTER_BITS ||
2098 (1 << cluster_bits) != cluster_size)
2099 {
2100 error_setg(errp, "Cluster size must be a power of two between %d and "
2101 "%dk", 1 << MIN_CLUSTER_BITS, 1 << (MAX_CLUSTER_BITS - 10));
2102 return -EINVAL;
2103 }
2104
2105 /*
2106 * Open the image file and write a minimal qcow2 header.
2107 *
2108 * We keep things simple and start with a zero-sized image. We also
2109 * do without refcount blocks or a L1 table for now. We'll fix the
2110 * inconsistency later.
2111 *
2112 * We do need a refcount table because growing the refcount table means
2113 * allocating two new refcount blocks - the seconds of which would be at
2114 * 2 GB for 64k clusters, and we don't want to have a 2 GB initial file
2115 * size for any qcow2 image.
2116 */
2117 BlockBackend *blk;
2118 QCowHeader *header;
2119 uint64_t* refcount_table;
2120 Error *local_err = NULL;
2121 int ret;
2122
2123 if (prealloc == PREALLOC_MODE_FULL || prealloc == PREALLOC_MODE_FALLOC) {
2124 /* Note: The following calculation does not need to be exact; if it is a
2125 * bit off, either some bytes will be "leaked" (which is fine) or we
2126 * will need to increase the file size by some bytes (which is fine,
2127 * too, as long as the bulk is allocated here). Therefore, using
2128 * floating point arithmetic is fine. */
2129 int64_t meta_size = 0;
2130 uint64_t nreftablee, nrefblocke, nl1e, nl2e;
2131 int64_t aligned_total_size = align_offset(total_size, cluster_size);
2132 int refblock_bits, refblock_size;
2133 /* refcount entry size in bytes */
2134 double rces = (1 << refcount_order) / 8.;
2135
2136 /* see qcow2_open() */
2137 refblock_bits = cluster_bits - (refcount_order - 3);
2138 refblock_size = 1 << refblock_bits;
2139
2140 /* header: 1 cluster */
2141 meta_size += cluster_size;
2142
2143 /* total size of L2 tables */
2144 nl2e = aligned_total_size / cluster_size;
2145 nl2e = align_offset(nl2e, cluster_size / sizeof(uint64_t));
2146 meta_size += nl2e * sizeof(uint64_t);
2147
2148 /* total size of L1 tables */
2149 nl1e = nl2e * sizeof(uint64_t) / cluster_size;
2150 nl1e = align_offset(nl1e, cluster_size / sizeof(uint64_t));
2151 meta_size += nl1e * sizeof(uint64_t);
2152
2153 /* total size of refcount blocks
2154 *
2155 * note: every host cluster is reference-counted, including metadata
2156 * (even refcount blocks are recursively included).
2157 * Let:
2158 * a = total_size (this is the guest disk size)
2159 * m = meta size not including refcount blocks and refcount tables
2160 * c = cluster size
2161 * y1 = number of refcount blocks entries
2162 * y2 = meta size including everything
2163 * rces = refcount entry size in bytes
2164 * then,
2165 * y1 = (y2 + a)/c
2166 * y2 = y1 * rces + y1 * rces * sizeof(u64) / c + m
2167 * we can get y1:
2168 * y1 = (a + m) / (c - rces - rces * sizeof(u64) / c)
2169 */
2170 nrefblocke = (aligned_total_size + meta_size + cluster_size)
2171 / (cluster_size - rces - rces * sizeof(uint64_t)
2172 / cluster_size);
2173 meta_size += DIV_ROUND_UP(nrefblocke, refblock_size) * cluster_size;
2174
2175 /* total size of refcount tables */
2176 nreftablee = nrefblocke / refblock_size;
2177 nreftablee = align_offset(nreftablee, cluster_size / sizeof(uint64_t));
2178 meta_size += nreftablee * sizeof(uint64_t);
2179
2180 qemu_opt_set_number(opts, BLOCK_OPT_SIZE,
2181 aligned_total_size + meta_size, &error_abort);
2182 qemu_opt_set(opts, BLOCK_OPT_PREALLOC, PreallocMode_lookup[prealloc],
2183 &error_abort);
2184 }
2185
2186 ret = bdrv_create_file(filename, opts, &local_err);
2187 if (ret < 0) {
2188 error_propagate(errp, local_err);
2189 return ret;
2190 }
2191
2192 blk = blk_new_open(filename, NULL, NULL,
2193 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
2194 if (blk == NULL) {
2195 error_propagate(errp, local_err);
2196 return -EIO;
2197 }
2198
2199 blk_set_allow_write_beyond_eof(blk, true);
2200
2201 /* Write the header */
2202 QEMU_BUILD_BUG_ON((1 << MIN_CLUSTER_BITS) < sizeof(*header));
2203 header = g_malloc0(cluster_size);
2204 *header = (QCowHeader) {
2205 .magic = cpu_to_be32(QCOW_MAGIC),
2206 .version = cpu_to_be32(version),
2207 .cluster_bits = cpu_to_be32(cluster_bits),
2208 .size = cpu_to_be64(0),
2209 .l1_table_offset = cpu_to_be64(0),
2210 .l1_size = cpu_to_be32(0),
2211 .refcount_table_offset = cpu_to_be64(cluster_size),
2212 .refcount_table_clusters = cpu_to_be32(1),
2213 .refcount_order = cpu_to_be32(refcount_order),
2214 .header_length = cpu_to_be32(sizeof(*header)),
2215 };
2216
2217 if (flags & BLOCK_FLAG_ENCRYPT) {
2218 header->crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
2219 } else {
2220 header->crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
2221 }
2222
2223 if (flags & BLOCK_FLAG_LAZY_REFCOUNTS) {
2224 header->compatible_features |=
2225 cpu_to_be64(QCOW2_COMPAT_LAZY_REFCOUNTS);
2226 }
2227
2228 ret = blk_pwrite(blk, 0, header, cluster_size, 0);
2229 g_free(header);
2230 if (ret < 0) {
2231 error_setg_errno(errp, -ret, "Could not write qcow2 header");
2232 goto out;
2233 }
2234
2235 /* Write a refcount table with one refcount block */
2236 refcount_table = g_malloc0(2 * cluster_size);
2237 refcount_table[0] = cpu_to_be64(2 * cluster_size);
2238 ret = blk_pwrite(blk, cluster_size, refcount_table, 2 * cluster_size, 0);
2239 g_free(refcount_table);
2240
2241 if (ret < 0) {
2242 error_setg_errno(errp, -ret, "Could not write refcount table");
2243 goto out;
2244 }
2245
2246 blk_unref(blk);
2247 blk = NULL;
2248
2249 /*
2250 * And now open the image and make it consistent first (i.e. increase the
2251 * refcount of the cluster that is occupied by the header and the refcount
2252 * table)
2253 */
2254 options = qdict_new();
2255 qdict_put(options, "driver", qstring_from_str("qcow2"));
2256 blk = blk_new_open(filename, NULL, options,
2257 BDRV_O_RDWR | BDRV_O_NO_FLUSH, &local_err);
2258 if (blk == NULL) {
2259 error_propagate(errp, local_err);
2260 ret = -EIO;
2261 goto out;
2262 }
2263
2264 ret = qcow2_alloc_clusters(blk_bs(blk), 3 * cluster_size);
2265 if (ret < 0) {
2266 error_setg_errno(errp, -ret, "Could not allocate clusters for qcow2 "
2267 "header and refcount table");
2268 goto out;
2269
2270 } else if (ret != 0) {
2271 error_report("Huh, first cluster in empty image is already in use?");
2272 abort();
2273 }
2274
2275 /* Create a full header (including things like feature table) */
2276 ret = qcow2_update_header(blk_bs(blk));
2277 if (ret < 0) {
2278 error_setg_errno(errp, -ret, "Could not update qcow2 header");
2279 goto out;
2280 }
2281
2282 /* Okay, now that we have a valid image, let's give it the right size */
2283 ret = blk_truncate(blk, total_size);
2284 if (ret < 0) {
2285 error_setg_errno(errp, -ret, "Could not resize image");
2286 goto out;
2287 }
2288
2289 /* Want a backing file? There you go.*/
2290 if (backing_file) {
2291 ret = bdrv_change_backing_file(blk_bs(blk), backing_file, backing_format);
2292 if (ret < 0) {
2293 error_setg_errno(errp, -ret, "Could not assign backing file '%s' "
2294 "with format '%s'", backing_file, backing_format);
2295 goto out;
2296 }
2297 }
2298
2299 /* And if we're supposed to preallocate metadata, do that now */
2300 if (prealloc != PREALLOC_MODE_OFF) {
2301 BDRVQcow2State *s = blk_bs(blk)->opaque;
2302 qemu_co_mutex_lock(&s->lock);
2303 ret = preallocate(blk_bs(blk));
2304 qemu_co_mutex_unlock(&s->lock);
2305 if (ret < 0) {
2306 error_setg_errno(errp, -ret, "Could not preallocate metadata");
2307 goto out;
2308 }
2309 }
2310
2311 blk_unref(blk);
2312 blk = NULL;
2313
2314 /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */
2315 options = qdict_new();
2316 qdict_put(options, "driver", qstring_from_str("qcow2"));
2317 blk = blk_new_open(filename, NULL, options,
2318 BDRV_O_RDWR | BDRV_O_NO_BACKING, &local_err);
2319 if (blk == NULL) {
2320 error_propagate(errp, local_err);
2321 ret = -EIO;
2322 goto out;
2323 }
2324
2325 ret = 0;
2326 out:
2327 if (blk) {
2328 blk_unref(blk);
2329 }
2330 return ret;
2331 }
2332
2333 static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
2334 {
2335 char *backing_file = NULL;
2336 char *backing_fmt = NULL;
2337 char *buf = NULL;
2338 uint64_t size = 0;
2339 int flags = 0;
2340 size_t cluster_size = DEFAULT_CLUSTER_SIZE;
2341 PreallocMode prealloc;
2342 int version = 3;
2343 uint64_t refcount_bits = 16;
2344 int refcount_order;
2345 Error *local_err = NULL;
2346 int ret;
2347
2348 /* Read out options */
2349 size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
2350 BDRV_SECTOR_SIZE);
2351 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
2352 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
2353 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
2354 flags |= BLOCK_FLAG_ENCRYPT;
2355 }
2356 cluster_size = qemu_opt_get_size_del(opts, BLOCK_OPT_CLUSTER_SIZE,
2357 DEFAULT_CLUSTER_SIZE);
2358 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
2359 prealloc = qapi_enum_parse(PreallocMode_lookup, buf,
2360 PREALLOC_MODE__MAX, PREALLOC_MODE_OFF,
2361 &local_err);
2362 if (local_err) {
2363 error_propagate(errp, local_err);
2364 ret = -EINVAL;
2365 goto finish;
2366 }
2367 g_free(buf);
2368 buf = qemu_opt_get_del(opts, BLOCK_OPT_COMPAT_LEVEL);
2369 if (!buf) {
2370 /* keep the default */
2371 } else if (!strcmp(buf, "0.10")) {
2372 version = 2;
2373 } else if (!strcmp(buf, "1.1")) {
2374 version = 3;
2375 } else {
2376 error_setg(errp, "Invalid compatibility level: '%s'", buf);
2377 ret = -EINVAL;
2378 goto finish;
2379 }
2380
2381 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_LAZY_REFCOUNTS, false)) {
2382 flags |= BLOCK_FLAG_LAZY_REFCOUNTS;
2383 }
2384
2385 if (backing_file && prealloc != PREALLOC_MODE_OFF) {
2386 error_setg(errp, "Backing file and preallocation cannot be used at "
2387 "the same time");
2388 ret = -EINVAL;
2389 goto finish;
2390 }
2391
2392 if (version < 3 && (flags & BLOCK_FLAG_LAZY_REFCOUNTS)) {
2393 error_setg(errp, "Lazy refcounts only supported with compatibility "
2394 "level 1.1 and above (use compat=1.1 or greater)");
2395 ret = -EINVAL;
2396 goto finish;
2397 }
2398
2399 refcount_bits = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_BITS,
2400 refcount_bits);
2401 if (refcount_bits > 64 || !is_power_of_2(refcount_bits)) {
2402 error_setg(errp, "Refcount width must be a power of two and may not "
2403 "exceed 64 bits");
2404 ret = -EINVAL;
2405 goto finish;
2406 }
2407
2408 if (version < 3 && refcount_bits != 16) {
2409 error_setg(errp, "Different refcount widths than 16 bits require "
2410 "compatibility level 1.1 or above (use compat=1.1 or "
2411 "greater)");
2412 ret = -EINVAL;
2413 goto finish;
2414 }
2415
2416 refcount_order = ctz32(refcount_bits);
2417
2418 ret = qcow2_create2(filename, size, backing_file, backing_fmt, flags,
2419 cluster_size, prealloc, opts, version, refcount_order,
2420 &local_err);
2421 error_propagate(errp, local_err);
2422
2423 finish:
2424 g_free(backing_file);
2425 g_free(backing_fmt);
2426 g_free(buf);
2427 return ret;
2428 }
2429
2430
2431 static bool is_zero_sectors(BlockDriverState *bs, int64_t start,
2432 uint32_t count)
2433 {
2434 int nr;
2435 BlockDriverState *file;
2436 int64_t res;
2437
2438 if (!count) {
2439 return true;
2440 }
2441 res = bdrv_get_block_status_above(bs, NULL, start, count,
2442 &nr, &file);
2443 return res >= 0 && (res & BDRV_BLOCK_ZERO) && nr == count;
2444 }
2445
2446 static coroutine_fn int qcow2_co_pwrite_zeroes(BlockDriverState *bs,
2447 int64_t offset, int count, BdrvRequestFlags flags)
2448 {
2449 int ret;
2450 BDRVQcow2State *s = bs->opaque;
2451
2452 uint32_t head = offset % s->cluster_size;
2453 uint32_t tail = (offset + count) % s->cluster_size;
2454
2455 trace_qcow2_pwrite_zeroes_start_req(qemu_coroutine_self(), offset, count);
2456
2457 if (head || tail) {
2458 int64_t cl_start = (offset - head) >> BDRV_SECTOR_BITS;
2459 uint64_t off;
2460 unsigned int nr;
2461
2462 assert(head + count <= s->cluster_size);
2463
2464 /* check whether remainder of cluster already reads as zero */
2465 if (!(is_zero_sectors(bs, cl_start,
2466 DIV_ROUND_UP(head, BDRV_SECTOR_SIZE)) &&
2467 is_zero_sectors(bs, (offset + count) >> BDRV_SECTOR_BITS,
2468 DIV_ROUND_UP(-tail & (s->cluster_size - 1),
2469 BDRV_SECTOR_SIZE)))) {
2470 return -ENOTSUP;
2471 }
2472
2473 qemu_co_mutex_lock(&s->lock);
2474 /* We can have new write after previous check */
2475 offset = cl_start << BDRV_SECTOR_BITS;
2476 count = s->cluster_size;
2477 nr = s->cluster_size;
2478 ret = qcow2_get_cluster_offset(bs, offset, &nr, &off);
2479 if (ret != QCOW2_CLUSTER_UNALLOCATED && ret != QCOW2_CLUSTER_ZERO) {
2480 qemu_co_mutex_unlock(&s->lock);
2481 return -ENOTSUP;
2482 }
2483 } else {
2484 qemu_co_mutex_lock(&s->lock);
2485 }
2486
2487 trace_qcow2_pwrite_zeroes(qemu_coroutine_self(), offset, count);
2488
2489 /* Whatever is left can use real zero clusters */
2490 ret = qcow2_zero_clusters(bs, offset, count >> BDRV_SECTOR_BITS, flags);
2491 qemu_co_mutex_unlock(&s->lock);
2492
2493 return ret;
2494 }
2495
2496 static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
2497 int64_t offset, int count)
2498 {
2499 int ret;
2500 BDRVQcow2State *s = bs->opaque;
2501
2502 if (!QEMU_IS_ALIGNED(offset | count, s->cluster_size)) {
2503 assert(count < s->cluster_size);
2504 return -ENOTSUP;
2505 }
2506
2507 qemu_co_mutex_lock(&s->lock);
2508 ret = qcow2_discard_clusters(bs, offset, count >> BDRV_SECTOR_BITS,
2509 QCOW2_DISCARD_REQUEST, false);
2510 qemu_co_mutex_unlock(&s->lock);
2511 return ret;
2512 }
2513
2514 static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
2515 {
2516 BDRVQcow2State *s = bs->opaque;
2517 int64_t new_l1_size;
2518 int ret;
2519
2520 if (offset & 511) {
2521 error_report("The new size must be a multiple of 512");
2522 return -EINVAL;
2523 }
2524
2525 /* cannot proceed if image has snapshots */
2526 if (s->nb_snapshots) {
2527 error_report("Can't resize an image which has snapshots");
2528 return -ENOTSUP;
2529 }
2530
2531 /* shrinking is currently not supported */
2532 if (offset < bs->total_sectors * 512) {
2533 error_report("qcow2 doesn't support shrinking images yet");
2534 return -ENOTSUP;
2535 }
2536
2537 new_l1_size = size_to_l1(s, offset);
2538 ret = qcow2_grow_l1_table(bs, new_l1_size, true);
2539 if (ret < 0) {
2540 return ret;
2541 }
2542
2543 /* write updated header.size */
2544 offset = cpu_to_be64(offset);
2545 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
2546 &offset, sizeof(uint64_t));
2547 if (ret < 0) {
2548 return ret;
2549 }
2550
2551 s->l1_vm_state_index = new_l1_size;
2552 return 0;
2553 }
2554
2555 /* XXX: put compressed sectors first, then all the cluster aligned
2556 tables to avoid losing bytes in alignment */
2557 static coroutine_fn int
2558 qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
2559 uint64_t bytes, QEMUIOVector *qiov)
2560 {
2561 BDRVQcow2State *s = bs->opaque;
2562 QEMUIOVector hd_qiov;
2563 struct iovec iov;
2564 z_stream strm;
2565 int ret, out_len;
2566 uint8_t *buf, *out_buf;
2567 uint64_t cluster_offset;
2568
2569 if (bytes == 0) {
2570 /* align end of file to a sector boundary to ease reading with
2571 sector based I/Os */
2572 cluster_offset = bdrv_getlength(bs->file->bs);
2573 return bdrv_truncate(bs->file->bs, cluster_offset);
2574 }
2575
2576 buf = qemu_blockalign(bs, s->cluster_size);
2577 if (bytes != s->cluster_size) {
2578 if (bytes > s->cluster_size ||
2579 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
2580 {
2581 qemu_vfree(buf);
2582 return -EINVAL;
2583 }
2584 /* Zero-pad last write if image size is not cluster aligned */
2585 memset(buf + bytes, 0, s->cluster_size - bytes);
2586 }
2587 qemu_iovec_to_buf(qiov, 0, buf, bytes);
2588
2589 out_buf = g_malloc(s->cluster_size);
2590
2591 /* best compression, small window, no zlib header */
2592 memset(&strm, 0, sizeof(strm));
2593 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
2594 Z_DEFLATED, -12,
2595 9, Z_DEFAULT_STRATEGY);
2596 if (ret != 0) {
2597 ret = -EINVAL;
2598 goto fail;
2599 }
2600
2601 strm.avail_in = s->cluster_size;
2602 strm.next_in = (uint8_t *)buf;
2603 strm.avail_out = s->cluster_size;
2604 strm.next_out = out_buf;
2605
2606 ret = deflate(&strm, Z_FINISH);
2607 if (ret != Z_STREAM_END && ret != Z_OK) {
2608 deflateEnd(&strm);
2609 ret = -EINVAL;
2610 goto fail;
2611 }
2612 out_len = strm.next_out - out_buf;
2613
2614 deflateEnd(&strm);
2615
2616 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
2617 /* could not compress: write normal cluster */
2618 ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);
2619 if (ret < 0) {
2620 goto fail;
2621 }
2622 goto success;
2623 }
2624
2625 qemu_co_mutex_lock(&s->lock);
2626 cluster_offset =
2627 qcow2_alloc_compressed_cluster_offset(bs, offset, out_len);
2628 if (!cluster_offset) {
2629 qemu_co_mutex_unlock(&s->lock);
2630 ret = -EIO;
2631 goto fail;
2632 }
2633 cluster_offset &= s->cluster_offset_mask;
2634
2635 ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
2636 qemu_co_mutex_unlock(&s->lock);
2637 if (ret < 0) {
2638 goto fail;
2639 }
2640
2641 iov = (struct iovec) {
2642 .iov_base = out_buf,
2643 .iov_len = out_len,
2644 };
2645 qemu_iovec_init_external(&hd_qiov, &iov, 1);
2646
2647 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
2648 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);
2649 if (ret < 0) {
2650 goto fail;
2651 }
2652 success:
2653 ret = 0;
2654 fail:
2655 qemu_vfree(buf);
2656 g_free(out_buf);
2657 return ret;
2658 }
2659
2660 static int make_completely_empty(BlockDriverState *bs)
2661 {
2662 BDRVQcow2State *s = bs->opaque;
2663 int ret, l1_clusters;
2664 int64_t offset;
2665 uint64_t *new_reftable = NULL;
2666 uint64_t rt_entry, l1_size2;
2667 struct {
2668 uint64_t l1_offset;
2669 uint64_t reftable_offset;
2670 uint32_t reftable_clusters;
2671 } QEMU_PACKED l1_ofs_rt_ofs_cls;
2672
2673 ret = qcow2_cache_empty(bs, s->l2_table_cache);
2674 if (ret < 0) {
2675 goto fail;
2676 }
2677
2678 ret = qcow2_cache_empty(bs, s->refcount_block_cache);
2679 if (ret < 0) {
2680 goto fail;
2681 }
2682
2683 /* Refcounts will be broken utterly */
2684 ret = qcow2_mark_dirty(bs);
2685 if (ret < 0) {
2686 goto fail;
2687 }
2688
2689 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2690
2691 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2692 l1_size2 = (uint64_t)s->l1_size * sizeof(uint64_t);
2693
2694 /* After this call, neither the in-memory nor the on-disk refcount
2695 * information accurately describe the actual references */
2696
2697 ret = bdrv_pwrite_zeroes(bs->file, s->l1_table_offset,
2698 l1_clusters * s->cluster_size, 0);
2699 if (ret < 0) {
2700 goto fail_broken_refcounts;
2701 }
2702 memset(s->l1_table, 0, l1_size2);
2703
2704 BLKDBG_EVENT(bs->file, BLKDBG_EMPTY_IMAGE_PREPARE);
2705
2706 /* Overwrite enough clusters at the beginning of the sectors to place
2707 * the refcount table, a refcount block and the L1 table in; this may
2708 * overwrite parts of the existing refcount and L1 table, which is not
2709 * an issue because the dirty flag is set, complete data loss is in fact
2710 * desired and partial data loss is consequently fine as well */
2711 ret = bdrv_pwrite_zeroes(bs->file, s->cluster_size,
2712 (2 + l1_clusters) * s->cluster_size, 0);
2713 /* This call (even if it failed overall) may have overwritten on-disk
2714 * refcount structures; in that case, the in-memory refcount information
2715 * will probably differ from the on-disk information which makes the BDS
2716 * unusable */
2717 if (ret < 0) {
2718 goto fail_broken_refcounts;
2719 }
2720
2721 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
2722 BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_UPDATE);
2723
2724 /* "Create" an empty reftable (one cluster) directly after the image
2725 * header and an empty L1 table three clusters after the image header;
2726 * the cluster between those two will be used as the first refblock */
2727 l1_ofs_rt_ofs_cls.l1_offset = cpu_to_be64(3 * s->cluster_size);
2728 l1_ofs_rt_ofs_cls.reftable_offset = cpu_to_be64(s->cluster_size);
2729 l1_ofs_rt_ofs_cls.reftable_clusters = cpu_to_be32(1);
2730 ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, l1_table_offset),
2731 &l1_ofs_rt_ofs_cls, sizeof(l1_ofs_rt_ofs_cls));
2732 if (ret < 0) {
2733 goto fail_broken_refcounts;
2734 }
2735
2736 s->l1_table_offset = 3 * s->cluster_size;
2737
2738 new_reftable = g_try_new0(uint64_t, s->cluster_size / sizeof(uint64_t));
2739 if (!new_reftable) {
2740 ret = -ENOMEM;
2741 goto fail_broken_refcounts;
2742 }
2743
2744 s->refcount_table_offset = s->cluster_size;
2745 s->refcount_table_size = s->cluster_size / sizeof(uint64_t);
2746
2747 g_free(s->refcount_table);
2748 s->refcount_table = new_reftable;
2749 new_reftable = NULL;
2750
2751 /* Now the in-memory refcount information again corresponds to the on-disk
2752 * information (reftable is empty and no refblocks (the refblock cache is
2753 * empty)); however, this means some clusters (e.g. the image header) are
2754 * referenced, but not refcounted, but the normal qcow2 code assumes that
2755 * the in-memory information is always correct */
2756
2757 BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC);
2758
2759 /* Enter the first refblock into the reftable */
2760 rt_entry = cpu_to_be64(2 * s->cluster_size);
2761 ret = bdrv_pwrite_sync(bs->file, s->cluster_size,
2762 &rt_entry, sizeof(rt_entry));
2763 if (ret < 0) {
2764 goto fail_broken_refcounts;
2765 }
2766 s->refcount_table[0] = 2 * s->cluster_size;
2767
2768 s->free_cluster_index = 0;
2769 assert(3 + l1_clusters <= s->refcount_block_size);
2770 offset = qcow2_alloc_clusters(bs, 3 * s->cluster_size + l1_size2);
2771 if (offset < 0) {
2772 ret = offset;
2773 goto fail_broken_refcounts;
2774 } else if (offset > 0) {
2775 error_report("First cluster in emptied image is in use");
2776 abort();
2777 }
2778
2779 /* Now finally the in-memory information corresponds to the on-disk
2780 * structures and is correct */
2781 ret = qcow2_mark_clean(bs);
2782 if (ret < 0) {
2783 goto fail;
2784 }
2785
2786 ret = bdrv_truncate(bs->file->bs, (3 + l1_clusters) * s->cluster_size);
2787 if (ret < 0) {
2788 goto fail;
2789 }
2790
2791 return 0;
2792
2793 fail_broken_refcounts:
2794 /* The BDS is unusable at this point. If we wanted to make it usable, we
2795 * would have to call qcow2_refcount_close(), qcow2_refcount_init(),
2796 * qcow2_check_refcounts(), qcow2_refcount_close() and qcow2_refcount_init()
2797 * again. However, because the functions which could have caused this error
2798 * path to be taken are used by those functions as well, it's very likely
2799 * that that sequence will fail as well. Therefore, just eject the BDS. */
2800 bs->drv = NULL;
2801
2802 fail:
2803 g_free(new_reftable);
2804 return ret;
2805 }
2806
2807 static int qcow2_make_empty(BlockDriverState *bs)
2808 {
2809 BDRVQcow2State *s = bs->opaque;
2810 uint64_t start_sector;
2811 int sector_step = (QEMU_ALIGN_DOWN(INT_MAX, s->cluster_size) /
2812 BDRV_SECTOR_SIZE);
2813 int l1_clusters, ret = 0;
2814
2815 l1_clusters = DIV_ROUND_UP(s->l1_size, s->cluster_size / sizeof(uint64_t));
2816
2817 if (s->qcow_version >= 3 && !s->snapshots &&
2818 3 + l1_clusters <= s->refcount_block_size) {
2819 /* The following function only works for qcow2 v3 images (it requires
2820 * the dirty flag) and only as long as there are no snapshots (because
2821 * it completely empties the image). Furthermore, the L1 table and three
2822 * additional clusters (image header, refcount table, one refcount
2823 * block) have to fit inside one refcount block. */
2824 return make_completely_empty(bs);
2825 }
2826
2827 /* This fallback code simply discards every active cluster; this is slow,
2828 * but works in all cases */
2829 for (start_sector = 0; start_sector < bs->total_sectors;
2830 start_sector += sector_step)
2831 {
2832 /* As this function is generally used after committing an external
2833 * snapshot, QCOW2_DISCARD_SNAPSHOT seems appropriate. Also, the
2834 * default action for this kind of discard is to pass the discard,
2835 * which will ideally result in an actually smaller image file, as
2836 * is probably desired. */
2837 ret = qcow2_discard_clusters(bs, start_sector * BDRV_SECTOR_SIZE,
2838 MIN(sector_step,
2839 bs->total_sectors - start_sector),
2840 QCOW2_DISCARD_SNAPSHOT, true);
2841 if (ret < 0) {
2842 break;
2843 }
2844 }
2845
2846 return ret;
2847 }
2848
2849 static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs)
2850 {
2851 BDRVQcow2State *s = bs->opaque;
2852 int ret;
2853
2854 qemu_co_mutex_lock(&s->lock);
2855 ret = qcow2_cache_write(bs, s->l2_table_cache);
2856 if (ret < 0) {
2857 qemu_co_mutex_unlock(&s->lock);
2858 return ret;
2859 }
2860
2861 if (qcow2_need_accurate_refcounts(s)) {
2862 ret = qcow2_cache_write(bs, s->refcount_block_cache);
2863 if (ret < 0) {
2864 qemu_co_mutex_unlock(&s->lock);
2865 return ret;
2866 }
2867 }
2868 qemu_co_mutex_unlock(&s->lock);
2869
2870 return 0;
2871 }
2872
2873 static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
2874 {
2875 BDRVQcow2State *s = bs->opaque;
2876 bdi->unallocated_blocks_are_zero = true;
2877 bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
2878 bdi->cluster_size = s->cluster_size;
2879 bdi->vm_state_offset = qcow2_vm_state_offset(s);
2880 return 0;
2881 }
2882
2883 static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
2884 {
2885 BDRVQcow2State *s = bs->opaque;
2886 ImageInfoSpecific *spec_info = g_new(ImageInfoSpecific, 1);
2887
2888 *spec_info = (ImageInfoSpecific){
2889 .type = IMAGE_INFO_SPECIFIC_KIND_QCOW2,
2890 .u.qcow2.data = g_new(ImageInfoSpecificQCow2, 1),
2891 };
2892 if (s->qcow_version == 2) {
2893 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
2894 .compat = g_strdup("0.10"),
2895 .refcount_bits = s->refcount_bits,
2896 };
2897 } else if (s->qcow_version == 3) {
2898 *spec_info->u.qcow2.data = (ImageInfoSpecificQCow2){
2899 .compat = g_strdup("1.1"),
2900 .lazy_refcounts = s->compatible_features &
2901 QCOW2_COMPAT_LAZY_REFCOUNTS,
2902 .has_lazy_refcounts = true,
2903 .corrupt = s->incompatible_features &
2904 QCOW2_INCOMPAT_CORRUPT,
2905 .has_corrupt = true,
2906 .refcount_bits = s->refcount_bits,
2907 };
2908 } else {
2909 /* if this assertion fails, this probably means a new version was
2910 * added without having it covered here */
2911 assert(false);
2912 }
2913
2914 return spec_info;
2915 }
2916
2917 #if 0
2918 static void dump_refcounts(BlockDriverState *bs)
2919 {
2920 BDRVQcow2State *s = bs->opaque;
2921 int64_t nb_clusters, k, k1, size;
2922 int refcount;
2923
2924 size = bdrv_getlength(bs->file->bs);
2925 nb_clusters = size_to_clusters(s, size);
2926 for(k = 0; k < nb_clusters;) {
2927 k1 = k;
2928 refcount = get_refcount(bs, k);
2929 k++;
2930 while (k < nb_clusters && get_refcount(bs, k) == refcount)
2931 k++;
2932 printf("%" PRId64 ": refcount=%d nb=%" PRId64 "\n", k, refcount,
2933 k - k1);
2934 }
2935 }
2936 #endif
2937
2938 static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
2939 int64_t pos)
2940 {
2941 BDRVQcow2State *s = bs->opaque;
2942
2943 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_SAVE);
2944 return bs->drv->bdrv_co_pwritev(bs, qcow2_vm_state_offset(s) + pos,
2945 qiov->size, qiov, 0);
2946 }
2947
2948 static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
2949 int64_t pos)
2950 {
2951 BDRVQcow2State *s = bs->opaque;
2952
2953 BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
2954 return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
2955 qiov->size, qiov, 0);
2956 }
2957
2958 /*
2959 * Downgrades an image's version. To achieve this, any incompatible features
2960 * have to be removed.
2961 */
2962 static int qcow2_downgrade(BlockDriverState *bs, int target_version,
2963 BlockDriverAmendStatusCB *status_cb, void *cb_opaque)
2964 {
2965 BDRVQcow2State *s = bs->opaque;
2966 int current_version = s->qcow_version;
2967 int ret;
2968
2969 if (target_version == current_version) {
2970 return 0;
2971 } else if (target_version > current_version) {
2972 return -EINVAL;
2973 } else if (target_version != 2) {
2974 return -EINVAL;
2975 }
2976
2977 if (s->refcount_order != 4) {
2978 error_report("compat=0.10 requires refcount_bits=16");
2979 return -ENOTSUP;
2980 }
2981
2982 /* clear incompatible features */
2983 if (s->incompatible_features & QCOW2_INCOMPAT_DIRTY) {
2984 ret = qcow2_mark_clean(bs);
2985 if (ret < 0) {
2986 return ret;
2987 }
2988 }
2989
2990 /* with QCOW2_INCOMPAT_CORRUPT, it is pretty much impossible to get here in
2991 * the first place; if that happens nonetheless, returning -ENOTSUP is the
2992 * best thing to do anyway */
2993
2994 if (s->incompatible_features) {
2995 return -ENOTSUP;
2996 }
2997
2998 /* since we can ignore compatible features, we can set them to 0 as well */
2999 s->compatible_features = 0;
3000 /* if lazy refcounts have been used, they have already been fixed through
3001 * clearing the dirty flag */
3002
3003 /* clearing autoclear features is trivial */
3004 s->autoclear_features = 0;
3005
3006 ret = qcow2_expand_zero_clusters(bs, status_cb, cb_opaque);
3007 if (ret < 0) {
3008 return ret;
3009 }
3010
3011 s->qcow_version = target_version;
3012 ret = qcow2_update_header(bs);
3013 if (ret < 0) {
3014 s->qcow_version = current_version;
3015 return ret;
3016 }
3017 return 0;
3018 }
3019
3020 typedef enum Qcow2AmendOperation {
3021 /* This is the value Qcow2AmendHelperCBInfo::last_operation will be
3022 * statically initialized to so that the helper CB can discern the first
3023 * invocation from an operation change */
3024 QCOW2_NO_OPERATION = 0,
3025
3026 QCOW2_CHANGING_REFCOUNT_ORDER,
3027 QCOW2_DOWNGRADING,
3028 } Qcow2AmendOperation;
3029
3030 typedef struct Qcow2AmendHelperCBInfo {
3031 /* The code coordinating the amend operations should only modify
3032 * these four fields; the rest will be managed by the CB */
3033 BlockDriverAmendStatusCB *original_status_cb;
3034 void *original_cb_opaque;
3035
3036 Qcow2AmendOperation current_operation;
3037
3038 /* Total number of operations to perform (only set once) */
3039 int total_operations;
3040
3041 /* The following fields are managed by the CB */
3042
3043 /* Number of operations completed */
3044 int operations_completed;
3045
3046 /* Cumulative offset of all completed operations */
3047 int64_t offset_completed;
3048
3049 Qcow2AmendOperation last_operation;
3050 int64_t last_work_size;
3051 } Qcow2AmendHelperCBInfo;
3052
3053 static void qcow2_amend_helper_cb(BlockDriverState *bs,
3054 int64_t operation_offset,
3055 int64_t operation_work_size, void *opaque)
3056 {
3057 Qcow2AmendHelperCBInfo *info = opaque;
3058 int64_t current_work_size;
3059 int64_t projected_work_size;
3060
3061 if (info->current_operation != info->last_operation) {
3062 if (info->last_operation != QCOW2_NO_OPERATION) {
3063 info->offset_completed += info->last_work_size;
3064 info->operations_completed++;
3065 }
3066
3067 info->last_operation = info->current_operation;
3068 }
3069
3070 assert(info->total_operations > 0);
3071 assert(info->operations_completed < info->total_operations);
3072
3073 info->last_work_size = operation_work_size;
3074
3075 current_work_size = info->offset_completed + operation_work_size;
3076
3077 /* current_work_size is the total work size for (operations_completed + 1)
3078 * operations (which includes this one), so multiply it by the number of
3079 * operations not covered and divide it by the number of operations
3080 * covered to get a projection for the operations not covered */
3081 projected_work_size = current_work_size * (info->total_operations -
3082 info->operations_completed - 1)
3083 / (info->operations_completed + 1);
3084
3085 info->original_status_cb(bs, info->offset_completed + operation_offset,
3086 current_work_size + projected_work_size,
3087 info->original_cb_opaque);
3088 }
3089
3090 static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
3091 BlockDriverAmendStatusCB *status_cb,
3092 void *cb_opaque)
3093 {
3094 BDRVQcow2State *s = bs->opaque;
3095 int old_version = s->qcow_version, new_version = old_version;
3096 uint64_t new_size = 0;
3097 const char *backing_file = NULL, *backing_format = NULL;
3098 bool lazy_refcounts = s->use_lazy_refcounts;
3099 const char *compat = NULL;
3100 uint64_t cluster_size = s->cluster_size;
3101 bool encrypt;
3102 int refcount_bits = s->refcount_bits;
3103 int ret;
3104 QemuOptDesc *desc = opts->list->desc;
3105 Qcow2AmendHelperCBInfo helper_cb_info;
3106
3107 while (desc && desc->name) {
3108 if (!qemu_opt_find(opts, desc->name)) {
3109 /* only change explicitly defined options */
3110 desc++;
3111 continue;
3112 }
3113
3114 if (!strcmp(desc->name, BLOCK_OPT_COMPAT_LEVEL)) {
3115 compat = qemu_opt_get(opts, BLOCK_OPT_COMPAT_LEVEL);
3116 if (!compat) {
3117 /* preserve default */
3118 } else if (!strcmp(compat, "0.10")) {
3119 new_version = 2;
3120 } else if (!strcmp(compat, "1.1")) {
3121 new_version = 3;
3122 } else {
3123 error_report("Unknown compatibility level %s", compat);
3124 return -EINVAL;
3125 }
3126 } else if (!strcmp(desc->name, BLOCK_OPT_PREALLOC)) {
3127 error_report("Cannot change preallocation mode");
3128 return -ENOTSUP;
3129 } else if (!strcmp(desc->name, BLOCK_OPT_SIZE)) {
3130 new_size = qemu_opt_get_size(opts, BLOCK_OPT_SIZE, 0);
3131 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FILE)) {
3132 backing_file = qemu_opt_get(opts, BLOCK_OPT_BACKING_FILE);
3133 } else if (!strcmp(desc->name, BLOCK_OPT_BACKING_FMT)) {
3134 backing_format = qemu_opt_get(opts, BLOCK_OPT_BACKING_FMT);
3135 } else if (!strcmp(desc->name, BLOCK_OPT_ENCRYPT)) {
3136 encrypt = qemu_opt_get_bool(opts, BLOCK_OPT_ENCRYPT,
3137 !!s->cipher);
3138
3139 if (encrypt != !!s->cipher) {
3140 error_report("Changing the encryption flag is not supported");
3141 return -ENOTSUP;
3142 }
3143 } else if (!strcmp(desc->name, BLOCK_OPT_CLUSTER_SIZE)) {
3144 cluster_size = qemu_opt_get_size(opts, BLOCK_OPT_CLUSTER_SIZE,
3145 cluster_size);
3146 if (cluster_size != s->cluster_size) {
3147 error_report("Changing the cluster size is not supported");
3148 return -ENOTSUP;
3149 }
3150 } else if (!strcmp(desc->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
3151 lazy_refcounts = qemu_opt_get_bool(opts, BLOCK_OPT_LAZY_REFCOUNTS,
3152 lazy_refcounts);
3153 } else if (!strcmp(desc->name, BLOCK_OPT_REFCOUNT_BITS)) {
3154 refcount_bits = qemu_opt_get_number(opts, BLOCK_OPT_REFCOUNT_BITS,
3155 refcount_bits);
3156
3157 if (refcount_bits <= 0 || refcount_bits > 64 ||
3158 !is_power_of_2(refcount_bits))
3159 {
3160 error_report("Refcount width must be a power of two and may "
3161 "not exceed 64 bits");
3162 return -EINVAL;
3163 }
3164 } else {
3165 /* if this point is reached, this probably means a new option was
3166 * added without having it covered here */
3167 abort();
3168 }
3169
3170 desc++;
3171 }
3172
3173 helper_cb_info = (Qcow2AmendHelperCBInfo){
3174 .original_status_cb = status_cb,
3175 .original_cb_opaque = cb_opaque,
3176 .total_operations = (new_version < old_version)
3177 + (s->refcount_bits != refcount_bits)
3178 };
3179
3180 /* Upgrade first (some features may require compat=1.1) */
3181 if (new_version > old_version) {
3182 s->qcow_version = new_version;
3183 ret = qcow2_update_header(bs);
3184 if (ret < 0) {
3185 s->qcow_version = old_version;
3186 return ret;
3187 }
3188 }
3189
3190 if (s->refcount_bits != refcount_bits) {
3191 int refcount_order = ctz32(refcount_bits);
3192 Error *local_error = NULL;
3193
3194 if (new_version < 3 && refcount_bits != 16) {
3195 error_report("Different refcount widths than 16 bits require "
3196 "compatibility level 1.1 or above (use compat=1.1 or "
3197 "greater)");
3198 return -EINVAL;
3199 }
3200
3201 helper_cb_info.current_operation = QCOW2_CHANGING_REFCOUNT_ORDER;
3202 ret = qcow2_change_refcount_order(bs, refcount_order,
3203 &qcow2_amend_helper_cb,
3204 &helper_cb_info, &local_error);
3205 if (ret < 0) {
3206 error_report_err(local_error);
3207 return ret;
3208 }
3209 }
3210
3211 if (backing_file || backing_format) {
3212 ret = qcow2_change_backing_file(bs,
3213 backing_file ?: s->image_backing_file,
3214 backing_format ?: s->image_backing_format);
3215 if (ret < 0) {
3216 return ret;
3217 }
3218 }
3219
3220 if (s->use_lazy_refcounts != lazy_refcounts) {
3221 if (lazy_refcounts) {
3222 if (new_version < 3) {
3223 error_report("Lazy refcounts only supported with compatibility "
3224 "level 1.1 and above (use compat=1.1 or greater)");
3225 return -EINVAL;
3226 }
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 = true;
3234 } else {
3235 /* make image clean first */
3236 ret = qcow2_mark_clean(bs);
3237 if (ret < 0) {
3238 return ret;
3239 }
3240 /* now disallow lazy refcounts */
3241 s->compatible_features &= ~QCOW2_COMPAT_LAZY_REFCOUNTS;
3242 ret = qcow2_update_header(bs);
3243 if (ret < 0) {
3244 s->compatible_features |= QCOW2_COMPAT_LAZY_REFCOUNTS;
3245 return ret;
3246 }
3247 s->use_lazy_refcounts = false;
3248 }
3249 }
3250
3251 if (new_size) {
3252 ret = bdrv_truncate(bs, new_size);
3253 if (ret < 0) {
3254 return ret;
3255 }
3256 }
3257
3258 /* Downgrade last (so unsupported features can be removed before) */
3259 if (new_version < old_version) {
3260 helper_cb_info.current_operation = QCOW2_DOWNGRADING;
3261 ret = qcow2_downgrade(bs, new_version, &qcow2_amend_helper_cb,
3262 &helper_cb_info);
3263 if (ret < 0) {
3264 return ret;
3265 }
3266 }
3267
3268 return 0;
3269 }
3270
3271 /*
3272 * If offset or size are negative, respectively, they will not be included in
3273 * the BLOCK_IMAGE_CORRUPTED event emitted.
3274 * fatal will be ignored for read-only BDS; corruptions found there will always
3275 * be considered non-fatal.
3276 */
3277 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
3278 int64_t size, const char *message_format, ...)
3279 {
3280 BDRVQcow2State *s = bs->opaque;
3281 const char *node_name;
3282 char *message;
3283 va_list ap;
3284
3285 fatal = fatal && !bs->read_only;
3286
3287 if (s->signaled_corruption &&
3288 (!fatal || (s->incompatible_features & QCOW2_INCOMPAT_CORRUPT)))
3289 {
3290 return;
3291 }
3292
3293 va_start(ap, message_format);
3294 message = g_strdup_vprintf(message_format, ap);
3295 va_end(ap);
3296
3297 if (fatal) {
3298 fprintf(stderr, "qcow2: Marking image as corrupt: %s; further "
3299 "corruption events will be suppressed\n", message);
3300 } else {
3301 fprintf(stderr, "qcow2: Image is corrupt: %s; further non-fatal "
3302 "corruption events will be suppressed\n", message);
3303 }
3304
3305 node_name = bdrv_get_node_name(bs);
3306 qapi_event_send_block_image_corrupted(bdrv_get_device_name(bs),
3307 *node_name != '\0', node_name,
3308 message, offset >= 0, offset,
3309 size >= 0, size,
3310 fatal, &error_abort);
3311 g_free(message);
3312
3313 if (fatal) {
3314 qcow2_mark_corrupt(bs);
3315 bs->drv = NULL; /* make BDS unusable */
3316 }
3317
3318 s->signaled_corruption = true;
3319 }
3320
3321 static QemuOptsList qcow2_create_opts = {
3322 .name = "qcow2-create-opts",
3323 .head = QTAILQ_HEAD_INITIALIZER(qcow2_create_opts.head),
3324 .desc = {
3325 {
3326 .name = BLOCK_OPT_SIZE,
3327 .type = QEMU_OPT_SIZE,
3328 .help = "Virtual disk size"
3329 },
3330 {
3331 .name = BLOCK_OPT_COMPAT_LEVEL,
3332 .type = QEMU_OPT_STRING,
3333 .help = "Compatibility level (0.10 or 1.1)"
3334 },
3335 {
3336 .name = BLOCK_OPT_BACKING_FILE,
3337 .type = QEMU_OPT_STRING,
3338 .help = "File name of a base image"
3339 },
3340 {
3341 .name = BLOCK_OPT_BACKING_FMT,
3342 .type = QEMU_OPT_STRING,
3343 .help = "Image format of the base image"
3344 },
3345 {
3346 .name = BLOCK_OPT_ENCRYPT,
3347 .type = QEMU_OPT_BOOL,
3348 .help = "Encrypt the image",
3349 .def_value_str = "off"
3350 },
3351 {
3352 .name = BLOCK_OPT_CLUSTER_SIZE,
3353 .type = QEMU_OPT_SIZE,
3354 .help = "qcow2 cluster size",
3355 .def_value_str = stringify(DEFAULT_CLUSTER_SIZE)
3356 },
3357 {
3358 .name = BLOCK_OPT_PREALLOC,
3359 .type = QEMU_OPT_STRING,
3360 .help = "Preallocation mode (allowed values: off, metadata, "
3361 "falloc, full)"
3362 },
3363 {
3364 .name = BLOCK_OPT_LAZY_REFCOUNTS,
3365 .type = QEMU_OPT_BOOL,
3366 .help = "Postpone refcount updates",
3367 .def_value_str = "off"
3368 },
3369 {
3370 .name = BLOCK_OPT_REFCOUNT_BITS,
3371 .type = QEMU_OPT_NUMBER,
3372 .help = "Width of a reference count entry in bits",
3373 .def_value_str = "16"
3374 },
3375 { /* end of list */ }
3376 }
3377 };
3378
3379 BlockDriver bdrv_qcow2 = {
3380 .format_name = "qcow2",
3381 .instance_size = sizeof(BDRVQcow2State),
3382 .bdrv_probe = qcow2_probe,
3383 .bdrv_open = qcow2_open,
3384 .bdrv_close = qcow2_close,
3385 .bdrv_reopen_prepare = qcow2_reopen_prepare,
3386 .bdrv_reopen_commit = qcow2_reopen_commit,
3387 .bdrv_reopen_abort = qcow2_reopen_abort,
3388 .bdrv_join_options = qcow2_join_options,
3389 .bdrv_create = qcow2_create,
3390 .bdrv_has_zero_init = bdrv_has_zero_init_1,
3391 .bdrv_co_get_block_status = qcow2_co_get_block_status,
3392 .bdrv_set_key = qcow2_set_key,