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meson: move keyutils dependency check
[qemu/kevin.git] / block / qcow.c
blobe514a86fe5e2f5fa4c68f7248898c2799075876d
1 /*
2 * Block driver for the QCOW 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
25 #include "qemu/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu/error-report.h"
28 #include "block/block_int.h"
29 #include "block/qdict.h"
30 #include "sysemu/block-backend.h"
31 #include "qemu/module.h"
32 #include "qemu/option.h"
33 #include "qemu/bswap.h"
34 #include "qemu/cutils.h"
35 #include <zlib.h>
36 #include "qapi/qmp/qdict.h"
37 #include "qapi/qmp/qstring.h"
38 #include "qapi/qobject-input-visitor.h"
39 #include "qapi/qapi-visit-block-core.h"
40 #include "crypto/block.h"
41 #include "migration/blocker.h"
42 #include "crypto.h"
43
44 /**************************************************************/
45 /* QEMU COW block driver with compression and encryption support */
46
47 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
48 #define QCOW_VERSION 1
49
50 #define QCOW_CRYPT_NONE 0
51 #define QCOW_CRYPT_AES 1
52
53 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
54
55 typedef struct QCowHeader {
56 uint32_t magic;
57 uint32_t version;
58 uint64_t backing_file_offset;
59 uint32_t backing_file_size;
60 uint32_t mtime;
61 uint64_t size; /* in bytes */
62 uint8_t cluster_bits;
63 uint8_t l2_bits;
64 uint16_t padding;
65 uint32_t crypt_method;
66 uint64_t l1_table_offset;
67 } QEMU_PACKED QCowHeader;
68
69 #define L2_CACHE_SIZE 16
70
71 typedef struct BDRVQcowState {
72 int cluster_bits;
73 int cluster_size;
74 int l2_bits;
75 int l2_size;
76 unsigned int l1_size;
77 uint64_t cluster_offset_mask;
78 uint64_t l1_table_offset;
79 uint64_t *l1_table;
80 uint64_t *l2_cache;
81 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
82 uint32_t l2_cache_counts[L2_CACHE_SIZE];
83 uint8_t *cluster_cache;
84 uint8_t *cluster_data;
85 uint64_t cluster_cache_offset;
86 QCryptoBlock *crypto; /* Disk encryption format driver */
87 uint32_t crypt_method_header;
88 CoMutex lock;
89 Error *migration_blocker;
90 } BDRVQcowState;
91
92 static QemuOptsList qcow_create_opts;
93
94 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
95
96 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
97 {
98 const QCowHeader *cow_header = (const void *)buf;
99
100 if (buf_size >= sizeof(QCowHeader) &&
101 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
102 be32_to_cpu(cow_header->version) == QCOW_VERSION)
103 return 100;
104 else
105 return 0;
106 }
107
108 static QemuOptsList qcow_runtime_opts = {
109 .name = "qcow",
110 .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head),
111 .desc = {
112 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
113 { /* end of list */ }
114 },
115 };
116
117 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
118 Error **errp)
119 {
120 BDRVQcowState *s = bs->opaque;
121 unsigned int len, i, shift;
122 int ret;
123 QCowHeader header;
124 QCryptoBlockOpenOptions *crypto_opts = NULL;
125 unsigned int cflags = 0;
126 QDict *encryptopts = NULL;
127 const char *encryptfmt;
128
129 qdict_extract_subqdict(options, &encryptopts, "encrypt.");
130 encryptfmt = qdict_get_try_str(encryptopts, "format");
131
132 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
133 BDRV_CHILD_IMAGE, false, errp);
134 if (!bs->file) {
135 ret = -EINVAL;
136 goto fail;
137 }
138
139 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
140 if (ret < 0) {
141 goto fail;
142 }
143 header.magic = be32_to_cpu(header.magic);
144 header.version = be32_to_cpu(header.version);
145 header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
146 header.backing_file_size = be32_to_cpu(header.backing_file_size);
147 header.mtime = be32_to_cpu(header.mtime);
148 header.size = be64_to_cpu(header.size);
149 header.crypt_method = be32_to_cpu(header.crypt_method);
150 header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
151
152 if (header.magic != QCOW_MAGIC) {
153 error_setg(errp, "Image not in qcow format");
154 ret = -EINVAL;
155 goto fail;
156 }
157 if (header.version != QCOW_VERSION) {
158 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32,
159 QCOW_VERSION, header.version);
160 if (header.version == 2 || header.version == 3) {
161 error_append_hint(errp, "Try the 'qcow2' driver instead.\n");
162 }
163
164 ret = -ENOTSUP;
165 goto fail;
166 }
167
168 if (header.size <= 1) {
169 error_setg(errp, "Image size is too small (must be at least 2 bytes)");
170 ret = -EINVAL;
171 goto fail;
172 }
173 if (header.cluster_bits < 9 || header.cluster_bits > 16) {
174 error_setg(errp, "Cluster size must be between 512 and 64k");
175 ret = -EINVAL;
176 goto fail;
177 }
178
179 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
180 * so bytes = num_entries << 3. */
181 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
182 error_setg(errp, "L2 table size must be between 512 and 64k");
183 ret = -EINVAL;
184 goto fail;
185 }
186
187 s->crypt_method_header = header.crypt_method;
188 if (s->crypt_method_header) {
189 if (bdrv_uses_whitelist() &&
190 s->crypt_method_header == QCOW_CRYPT_AES) {
191 error_setg(errp,
192 "Use of AES-CBC encrypted qcow images is no longer "
193 "supported in system emulators");
194 error_append_hint(errp,
195 "You can use 'qemu-img convert' to convert your "
196 "image to an alternative supported format, such "
197 "as unencrypted qcow, or raw with the LUKS "
198 "format instead.\n");
199 ret = -ENOSYS;
200 goto fail;
201 }
202 if (s->crypt_method_header == QCOW_CRYPT_AES) {
203 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
204 error_setg(errp,
205 "Header reported 'aes' encryption format but "
206 "options specify '%s'", encryptfmt);
207 ret = -EINVAL;
208 goto fail;
209 }
210 qdict_put_str(encryptopts, "format", "qcow");
211 crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
212 if (!crypto_opts) {
213 ret = -EINVAL;
214 goto fail;
215 }
216
217 if (flags & BDRV_O_NO_IO) {
218 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
219 }
220 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
221 NULL, NULL, cflags, 1, errp);
222 if (!s->crypto) {
223 ret = -EINVAL;
224 goto fail;
225 }
226 } else {
227 error_setg(errp, "invalid encryption method in qcow header");
228 ret = -EINVAL;
229 goto fail;
230 }
231 bs->encrypted = true;
232 } else {
233 if (encryptfmt) {
234 error_setg(errp, "No encryption in image header, but options "
235 "specified format '%s'", encryptfmt);
236 ret = -EINVAL;
237 goto fail;
238 }
239 }
240 s->cluster_bits = header.cluster_bits;
241 s->cluster_size = 1 << s->cluster_bits;
242 s->l2_bits = header.l2_bits;
243 s->l2_size = 1 << s->l2_bits;
244 bs->total_sectors = header.size / 512;
245 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
246
247 /* read the level 1 table */
248 shift = s->cluster_bits + s->l2_bits;
249 if (header.size > UINT64_MAX - (1LL << shift)) {
250 error_setg(errp, "Image too large");
251 ret = -EINVAL;
252 goto fail;
253 } else {
254 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
255 if (l1_size > INT_MAX / sizeof(uint64_t)) {
256 error_setg(errp, "Image too large");
257 ret = -EINVAL;
258 goto fail;
259 }
260 s->l1_size = l1_size;
261 }
262
263 s->l1_table_offset = header.l1_table_offset;
264 s->l1_table = g_try_new(uint64_t, s->l1_size);
265 if (s->l1_table == NULL) {
266 error_setg(errp, "Could not allocate memory for L1 table");
267 ret = -ENOMEM;
268 goto fail;
269 }
270
271 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
272 s->l1_size * sizeof(uint64_t));
273 if (ret < 0) {
274 goto fail;
275 }
276
277 for(i = 0;i < s->l1_size; i++) {
278 s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
279 }
280
281 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
282 s->l2_cache =
283 qemu_try_blockalign(bs->file->bs,
284 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
285 if (s->l2_cache == NULL) {
286 error_setg(errp, "Could not allocate L2 table cache");
287 ret = -ENOMEM;
288 goto fail;
289 }
290 s->cluster_cache = g_malloc(s->cluster_size);
291 s->cluster_data = g_malloc(s->cluster_size);
292 s->cluster_cache_offset = -1;
293
294 /* read the backing file name */
295 if (header.backing_file_offset != 0) {
296 len = header.backing_file_size;
297 if (len > 1023 || len >= sizeof(bs->backing_file)) {
298 error_setg(errp, "Backing file name too long");
299 ret = -EINVAL;
300 goto fail;
301 }
302 ret = bdrv_pread(bs->file, header.backing_file_offset,
303 bs->auto_backing_file, len);
304 if (ret < 0) {
305 goto fail;
306 }
307 bs->auto_backing_file[len] = '\0';
308 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
309 bs->auto_backing_file);
310 }
311
312 /* Disable migration when qcow images are used */
313 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
314 "does not support live migration",
315 bdrv_get_device_or_node_name(bs));
316 ret = migrate_add_blocker(s->migration_blocker, errp);
317 if (ret < 0) {
318 error_free(s->migration_blocker);
319 goto fail;
320 }
321
322 qobject_unref(encryptopts);
323 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
324 qemu_co_mutex_init(&s->lock);
325 return 0;
326
327 fail:
328 g_free(s->l1_table);
329 qemu_vfree(s->l2_cache);
330 g_free(s->cluster_cache);
331 g_free(s->cluster_data);
332 qcrypto_block_free(s->crypto);
333 qobject_unref(encryptopts);
334 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
335 return ret;
336 }
337
338
339 /* We have nothing to do for QCOW reopen, stubs just return
340 * success */
341 static int qcow_reopen_prepare(BDRVReopenState *state,
342 BlockReopenQueue *queue, Error **errp)
343 {
344 return 0;
345 }
346
347
348 /* 'allocate' is:
349 *
350 * 0 to not allocate.
351 *
352 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
353 * to 'n_end' within the cluster)
354 *
355 * 2 to allocate a compressed cluster of size
356 * 'compressed_size'. 'compressed_size' must be > 0 and <
357 * cluster_size
358 *
359 * return 0 if not allocated, 1 if *result is assigned, and negative
360 * errno on failure.
361 */
362 static int get_cluster_offset(BlockDriverState *bs,
363 uint64_t offset, int allocate,
364 int compressed_size,
365 int n_start, int n_end, uint64_t *result)
366 {
367 BDRVQcowState *s = bs->opaque;
368 int min_index, i, j, l1_index, l2_index, ret;
369 int64_t l2_offset;
370 uint64_t *l2_table, cluster_offset, tmp;
371 uint32_t min_count;
372 int new_l2_table;
373
374 *result = 0;
375 l1_index = offset >> (s->l2_bits + s->cluster_bits);
376 l2_offset = s->l1_table[l1_index];
377 new_l2_table = 0;
378 if (!l2_offset) {
379 if (!allocate)
380 return 0;
381 /* allocate a new l2 entry */
382 l2_offset = bdrv_getlength(bs->file->bs);
383 if (l2_offset < 0) {
384 return l2_offset;
385 }
386 /* round to cluster size */
387 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
388 /* update the L1 entry */
389 s->l1_table[l1_index] = l2_offset;
390 tmp = cpu_to_be64(l2_offset);
391 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
392 ret = bdrv_pwrite_sync(bs->file,
393 s->l1_table_offset + l1_index * sizeof(tmp),
394 &tmp, sizeof(tmp));
395 if (ret < 0) {
396 return ret;
397 }
398 new_l2_table = 1;
399 }
400 for(i = 0; i < L2_CACHE_SIZE; i++) {
401 if (l2_offset == s->l2_cache_offsets[i]) {
402 /* increment the hit count */
403 if (++s->l2_cache_counts[i] == 0xffffffff) {
404 for(j = 0; j < L2_CACHE_SIZE; j++) {
405 s->l2_cache_counts[j] >>= 1;
406 }
407 }
408 l2_table = s->l2_cache + (i << s->l2_bits);
409 goto found;
410 }
411 }
412 /* not found: load a new entry in the least used one */
413 min_index = 0;
414 min_count = 0xffffffff;
415 for(i = 0; i < L2_CACHE_SIZE; i++) {
416 if (s->l2_cache_counts[i] < min_count) {
417 min_count = s->l2_cache_counts[i];
418 min_index = i;
419 }
420 }
421 l2_table = s->l2_cache + (min_index << s->l2_bits);
422 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
423 if (new_l2_table) {
424 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
425 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
426 s->l2_size * sizeof(uint64_t));
427 if (ret < 0) {
428 return ret;
429 }
430 } else {
431 ret = bdrv_pread(bs->file, l2_offset, l2_table,
432 s->l2_size * sizeof(uint64_t));
433 if (ret < 0) {
434 return ret;
435 }
436 }
437 s->l2_cache_offsets[min_index] = l2_offset;
438 s->l2_cache_counts[min_index] = 1;
439 found:
440 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
441 cluster_offset = be64_to_cpu(l2_table[l2_index]);
442 if (!cluster_offset ||
443 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
444 if (!allocate)
445 return 0;
446 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
447 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
448 /* allocate a new cluster */
449 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
450 (n_end - n_start) < s->cluster_size) {
451 /* if the cluster is already compressed, we must
452 decompress it in the case it is not completely
453 overwritten */
454 if (decompress_cluster(bs, cluster_offset) < 0) {
455 return -EIO;
456 }
457 cluster_offset = bdrv_getlength(bs->file->bs);
458 if ((int64_t) cluster_offset < 0) {
459 return cluster_offset;
460 }
461 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
462 /* write the cluster content */
463 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
464 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache,
465 s->cluster_size);
466 if (ret < 0) {
467 return ret;
468 }
469 } else {
470 cluster_offset = bdrv_getlength(bs->file->bs);
471 if ((int64_t) cluster_offset < 0) {
472 return cluster_offset;
473 }
474 if (allocate == 1) {
475 /* round to cluster size */
476 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
477 if (cluster_offset + s->cluster_size > INT64_MAX) {
478 return -E2BIG;
479 }
480 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size,
481 false, PREALLOC_MODE_OFF, 0, NULL);
482 if (ret < 0) {
483 return ret;
484 }
485 /* if encrypted, we must initialize the cluster
486 content which won't be written */
487 if (bs->encrypted &&
488 (n_end - n_start) < s->cluster_size) {
489 uint64_t start_offset;
490 assert(s->crypto);
491 start_offset = offset & ~(s->cluster_size - 1);
492 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
493 if (i < n_start || i >= n_end) {
494 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
495 if (qcrypto_block_encrypt(s->crypto,
496 start_offset + i,
497 s->cluster_data,
498 BDRV_SECTOR_SIZE,
499 NULL) < 0) {
500 return -EIO;
501 }
502 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
503 ret = bdrv_pwrite(bs->file,
504 cluster_offset + i,
505 s->cluster_data,
506 BDRV_SECTOR_SIZE);
507 if (ret < 0) {
508 return ret;
509 }
510 }
511 }
512 }
513 } else if (allocate == 2) {
514 cluster_offset |= QCOW_OFLAG_COMPRESSED |
515 (uint64_t)compressed_size << (63 - s->cluster_bits);
516 }
517 }
518 /* update L2 table */
519 tmp = cpu_to_be64(cluster_offset);
520 l2_table[l2_index] = tmp;
521 if (allocate == 2) {
522 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
523 } else {
524 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
525 }
526 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
527 &tmp, sizeof(tmp));
528 if (ret < 0) {
529 return ret;
530 }
531 }
532 *result = cluster_offset;
533 return 1;
534 }
535
536 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs,
537 bool want_zero,
538 int64_t offset, int64_t bytes,
539 int64_t *pnum, int64_t *map,
540 BlockDriverState **file)
541 {
542 BDRVQcowState *s = bs->opaque;
543 int index_in_cluster, ret;
544 int64_t n;
545 uint64_t cluster_offset;
546
547 qemu_co_mutex_lock(&s->lock);
548 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
549 qemu_co_mutex_unlock(&s->lock);
550 if (ret < 0) {
551 return ret;
552 }
553 index_in_cluster = offset & (s->cluster_size - 1);
554 n = s->cluster_size - index_in_cluster;
555 if (n > bytes) {
556 n = bytes;
557 }
558 *pnum = n;
559 if (!cluster_offset) {
560 return 0;
561 }
562 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) {
563 return BDRV_BLOCK_DATA;
564 }
565 *map = cluster_offset | index_in_cluster;
566 *file = bs->file->bs;
567 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
568 }
569
570 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
571 const uint8_t *buf, int buf_size)
572 {
573 z_stream strm1, *strm = &strm1;
574 int ret, out_len;
575
576 memset(strm, 0, sizeof(*strm));
577
578 strm->next_in = (uint8_t *)buf;
579 strm->avail_in = buf_size;
580 strm->next_out = out_buf;
581 strm->avail_out = out_buf_size;
582
583 ret = inflateInit2(strm, -12);
584 if (ret != Z_OK)
585 return -1;
586 ret = inflate(strm, Z_FINISH);
587 out_len = strm->next_out - out_buf;
588 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
589 out_len != out_buf_size) {
590 inflateEnd(strm);
591 return -1;
592 }
593 inflateEnd(strm);
594 return 0;
595 }
596
597 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
598 {
599 BDRVQcowState *s = bs->opaque;
600 int ret, csize;
601 uint64_t coffset;
602
603 coffset = cluster_offset & s->cluster_offset_mask;
604 if (s->cluster_cache_offset != coffset) {
605 csize = cluster_offset >> (63 - s->cluster_bits);
606 csize &= (s->cluster_size - 1);
607 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
608 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
609 if (ret != csize)
610 return -1;
611 if (decompress_buffer(s->cluster_cache, s->cluster_size,
612 s->cluster_data, csize) < 0) {
613 return -1;
614 }
615 s->cluster_cache_offset = coffset;
616 }
617 return 0;
618 }
619
620 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
621 {
622 /* At least encrypted images require 512-byte alignment. Apply the
623 * limit universally, rather than just on encrypted images, as
624 * it's easier to let the block layer handle rounding than to
625 * audit this code further. */
626 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
627 }
628
629 static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset,
630 uint64_t bytes, QEMUIOVector *qiov,
631 int flags)
632 {
633 BDRVQcowState *s = bs->opaque;
634 int offset_in_cluster;
635 int ret = 0, n;
636 uint64_t cluster_offset;
637 uint8_t *buf;
638 void *orig_buf;
639
640 assert(!flags);
641 if (qiov->niov > 1) {
642 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
643 if (buf == NULL) {
644 return -ENOMEM;
645 }
646 } else {
647 orig_buf = NULL;
648 buf = (uint8_t *)qiov->iov->iov_base;
649 }
650
651 qemu_co_mutex_lock(&s->lock);
652
653 while (bytes != 0) {
654 /* prepare next request */
655 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
656 if (ret < 0) {
657 break;
658 }
659 offset_in_cluster = offset & (s->cluster_size - 1);
660 n = s->cluster_size - offset_in_cluster;
661 if (n > bytes) {
662 n = bytes;
663 }
664
665 if (!cluster_offset) {
666 if (bs->backing) {
667 /* read from the base image */
668 qemu_co_mutex_unlock(&s->lock);
669 /* qcow2 emits this on bs->file instead of bs->backing */
670 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
671 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
672 qemu_co_mutex_lock(&s->lock);
673 if (ret < 0) {
674 break;
675 }
676 } else {
677 /* Note: in this case, no need to wait */
678 memset(buf, 0, n);
679 }
680 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
681 /* add AIO support for compressed blocks ? */
682 if (decompress_cluster(bs, cluster_offset) < 0) {
683 ret = -EIO;
684 break;
685 }
686 memcpy(buf, s->cluster_cache + offset_in_cluster, n);
687 } else {
688 if ((cluster_offset & 511) != 0) {
689 ret = -EIO;
690 break;
691 }
692 qemu_co_mutex_unlock(&s->lock);
693 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
694 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
695 n, buf, 0);
696 qemu_co_mutex_lock(&s->lock);
697 if (ret < 0) {
698 break;
699 }
700 if (bs->encrypted) {
701 assert(s->crypto);
702 if (qcrypto_block_decrypt(s->crypto,
703 offset, buf, n, NULL) < 0) {
704 ret = -EIO;
705 break;
706 }
707 }
708 }
709 ret = 0;
710
711 bytes -= n;
712 offset += n;
713 buf += n;
714 }
715
716 qemu_co_mutex_unlock(&s->lock);
717
718 if (qiov->niov > 1) {
719 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
720 qemu_vfree(orig_buf);
721 }
722
723 return ret;
724 }
725
726 static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, uint64_t offset,
727 uint64_t bytes, QEMUIOVector *qiov,
728 int flags)
729 {
730 BDRVQcowState *s = bs->opaque;
731 int offset_in_cluster;
732 uint64_t cluster_offset;
733 int ret = 0, n;
734 uint8_t *buf;
735 void *orig_buf;
736
737 assert(!flags);
738 s->cluster_cache_offset = -1; /* disable compressed cache */
739
740 /* We must always copy the iov when encrypting, so we
741 * don't modify the original data buffer during encryption */
742 if (bs->encrypted || qiov->niov > 1) {
743 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
744 if (buf == NULL) {
745 return -ENOMEM;
746 }
747 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
748 } else {
749 orig_buf = NULL;
750 buf = (uint8_t *)qiov->iov->iov_base;
751 }
752
753 qemu_co_mutex_lock(&s->lock);
754
755 while (bytes != 0) {
756 offset_in_cluster = offset & (s->cluster_size - 1);
757 n = s->cluster_size - offset_in_cluster;
758 if (n > bytes) {
759 n = bytes;
760 }
761 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
762 offset_in_cluster + n, &cluster_offset);
763 if (ret < 0) {
764 break;
765 }
766 if (!cluster_offset || (cluster_offset & 511) != 0) {
767 ret = -EIO;
768 break;
769 }
770 if (bs->encrypted) {
771 assert(s->crypto);
772 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
773 ret = -EIO;
774 break;
775 }
776 }
777
778 qemu_co_mutex_unlock(&s->lock);
779 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
780 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
781 n, buf, 0);
782 qemu_co_mutex_lock(&s->lock);
783 if (ret < 0) {
784 break;
785 }
786 ret = 0;
787
788 bytes -= n;
789 offset += n;
790 buf += n;
791 }
792 qemu_co_mutex_unlock(&s->lock);
793
794 qemu_vfree(orig_buf);
795
796 return ret;
797 }
798
799 static void qcow_close(BlockDriverState *bs)
800 {
801 BDRVQcowState *s = bs->opaque;
802
803 qcrypto_block_free(s->crypto);
804 s->crypto = NULL;
805 g_free(s->l1_table);
806 qemu_vfree(s->l2_cache);
807 g_free(s->cluster_cache);
808 g_free(s->cluster_data);
809
810 migrate_del_blocker(s->migration_blocker);
811 error_free(s->migration_blocker);
812 }
813
814 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts,
815 Error **errp)
816 {
817 BlockdevCreateOptionsQcow *qcow_opts;
818 int header_size, backing_filename_len, l1_size, shift, i;
819 QCowHeader header;
820 uint8_t *tmp;
821 int64_t total_size = 0;
822 int ret;
823 BlockDriverState *bs;
824 BlockBackend *qcow_blk;
825 QCryptoBlock *crypto = NULL;
826
827 assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
828 qcow_opts = &opts->u.qcow;
829
830 /* Sanity checks */
831 total_size = qcow_opts->size;
832 if (total_size == 0) {
833 error_setg(errp, "Image size is too small, cannot be zero length");
834 return -EINVAL;
835 }
836
837 if (qcow_opts->has_encrypt &&
838 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
839 {
840 error_setg(errp, "Unsupported encryption format");
841 return -EINVAL;
842 }
843
844 /* Create BlockBackend to write to the image */
845 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp);
846 if (bs == NULL) {
847 return -EIO;
848 }
849
850 qcow_blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
851 BLK_PERM_ALL, errp);
852 if (!qcow_blk) {
853 ret = -EPERM;
854 goto exit;
855 }
856 blk_set_allow_write_beyond_eof(qcow_blk, true);
857
858 /* Create image format */
859 memset(&header, 0, sizeof(header));
860 header.magic = cpu_to_be32(QCOW_MAGIC);
861 header.version = cpu_to_be32(QCOW_VERSION);
862 header.size = cpu_to_be64(total_size);
863 header_size = sizeof(header);
864 backing_filename_len = 0;
865 if (qcow_opts->has_backing_file) {
866 if (strcmp(qcow_opts->backing_file, "fat:")) {
867 header.backing_file_offset = cpu_to_be64(header_size);
868 backing_filename_len = strlen(qcow_opts->backing_file);
869 header.backing_file_size = cpu_to_be32(backing_filename_len);
870 header_size += backing_filename_len;
871 } else {
872 /* special backing file for vvfat */
873 qcow_opts->has_backing_file = false;
874 }
875 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
876 unmodified sectors */
877 header.l2_bits = 12; /* 32 KB L2 tables */
878 } else {
879 header.cluster_bits = 12; /* 4 KB clusters */
880 header.l2_bits = 9; /* 4 KB L2 tables */
881 }
882 header_size = (header_size + 7) & ~7;
883 shift = header.cluster_bits + header.l2_bits;
884 l1_size = (total_size + (1LL << shift) - 1) >> shift;
885
886 header.l1_table_offset = cpu_to_be64(header_size);
887
888 if (qcow_opts->has_encrypt) {
889 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
890
891 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
892 NULL, NULL, NULL, errp);
893 if (!crypto) {
894 ret = -EINVAL;
895 goto exit;
896 }
897 } else {
898 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
899 }
900
901 /* write all the data */
902 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0);
903 if (ret != sizeof(header)) {
904 goto exit;
905 }
906
907 if (qcow_opts->has_backing_file) {
908 ret = blk_pwrite(qcow_blk, sizeof(header),
909 qcow_opts->backing_file, backing_filename_len, 0);
910 if (ret != backing_filename_len) {
911 goto exit;
912 }
913 }
914
915 tmp = g_malloc0(BDRV_SECTOR_SIZE);
916 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
917 i++) {
918 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
919 tmp, BDRV_SECTOR_SIZE, 0);
920 if (ret != BDRV_SECTOR_SIZE) {
921 g_free(tmp);
922 goto exit;
923 }
924 }
925
926 g_free(tmp);
927 ret = 0;
928 exit:
929 blk_unref(qcow_blk);
930 bdrv_unref(bs);
931 qcrypto_block_free(crypto);
932 return ret;
933 }
934
935 static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,
936 const char *filename,
937 QemuOpts *opts, Error **errp)
938 {
939 BlockdevCreateOptions *create_options = NULL;
940 BlockDriverState *bs = NULL;
941 QDict *qdict = NULL;
942 Visitor *v;
943 const char *val;
944 int ret;
945 char *backing_fmt;
946
947 static const QDictRenames opt_renames[] = {
948 { BLOCK_OPT_BACKING_FILE, "backing-file" },
949 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
950 { NULL, NULL },
951 };
952
953 /*
954 * We can't actually store a backing format, but can check that
955 * the user's request made sense.
956 */
957 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
958 if (backing_fmt && !bdrv_find_format(backing_fmt)) {
959 error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
960 ret = -EINVAL;
961 goto fail;
962 }
963
964 /* Parse options and convert legacy syntax */
965 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
966
967 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
968 if (val && !strcmp(val, "on")) {
969 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
970 } else if (val && !strcmp(val, "off")) {
971 qdict_del(qdict, BLOCK_OPT_ENCRYPT);
972 }
973
974 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
975 if (val && !strcmp(val, "aes")) {
976 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
977 }
978
979 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
980 ret = -EINVAL;
981 goto fail;
982 }
983
984 /* Create and open the file (protocol layer) */
985 ret = bdrv_create_file(filename, opts, errp);
986 if (ret < 0) {
987 goto fail;
988 }
989
990 bs = bdrv_open(filename, NULL, NULL,
991 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
992 if (bs == NULL) {
993 ret = -EIO;
994 goto fail;
995 }
996
997 /* Now get the QAPI type BlockdevCreateOptions */
998 qdict_put_str(qdict, "driver", "qcow");
999 qdict_put_str(qdict, "file", bs->node_name);
1000
1001 v = qobject_input_visitor_new_flat_confused(qdict, errp);
1002 if (!v) {
1003 ret = -EINVAL;
1004 goto fail;
1005 }
1006
1007 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
1008 visit_free(v);
1009 if (!create_options) {
1010 ret = -EINVAL;
1011 goto fail;
1012 }
1013
1014 /* Silently round up size */
1015 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1016 create_options->u.qcow.size =
1017 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1018
1019 /* Create the qcow image (format layer) */
1020 ret = qcow_co_create(create_options, errp);
1021 if (ret < 0) {
1022 goto fail;
1023 }
1024
1025 ret = 0;
1026 fail:
1027 g_free(backing_fmt);
1028 qobject_unref(qdict);
1029 bdrv_unref(bs);
1030 qapi_free_BlockdevCreateOptions(create_options);
1031 return ret;
1032 }
1033
1034 static int qcow_make_empty(BlockDriverState *bs)
1035 {
1036 BDRVQcowState *s = bs->opaque;
1037 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1038 int ret;
1039
1040 memset(s->l1_table, 0, l1_length);
1041 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
1042 l1_length) < 0)
1043 return -1;
1044 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1045 PREALLOC_MODE_OFF, 0, NULL);
1046 if (ret < 0)
1047 return ret;
1048
1049 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1050 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1051 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1052
1053 return 0;
1054 }
1055
1056 /* XXX: put compressed sectors first, then all the cluster aligned
1057 tables to avoid losing bytes in alignment */
1058 static coroutine_fn int
1059 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
1060 uint64_t bytes, QEMUIOVector *qiov)
1061 {
1062 BDRVQcowState *s = bs->opaque;
1063 z_stream strm;
1064 int ret, out_len;
1065 uint8_t *buf, *out_buf;
1066 uint64_t cluster_offset;
1067
1068 buf = qemu_blockalign(bs, s->cluster_size);
1069 if (bytes != s->cluster_size) {
1070 if (bytes > s->cluster_size ||
1071 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1072 {
1073 qemu_vfree(buf);
1074 return -EINVAL;
1075 }
1076 /* Zero-pad last write if image size is not cluster aligned */
1077 memset(buf + bytes, 0, s->cluster_size - bytes);
1078 }
1079 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1080
1081 out_buf = g_malloc(s->cluster_size);
1082
1083 /* best compression, small window, no zlib header */
1084 memset(&strm, 0, sizeof(strm));
1085 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1086 Z_DEFLATED, -12,
1087 9, Z_DEFAULT_STRATEGY);
1088 if (ret != 0) {
1089 ret = -EINVAL;
1090 goto fail;
1091 }
1092
1093 strm.avail_in = s->cluster_size;
1094 strm.next_in = (uint8_t *)buf;
1095 strm.avail_out = s->cluster_size;
1096 strm.next_out = out_buf;
1097
1098 ret = deflate(&strm, Z_FINISH);
1099 if (ret != Z_STREAM_END && ret != Z_OK) {
1100 deflateEnd(&strm);
1101 ret = -EINVAL;
1102 goto fail;
1103 }
1104 out_len = strm.next_out - out_buf;
1105
1106 deflateEnd(&strm);
1107
1108 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1109 /* could not compress: write normal cluster */
1110 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1111 if (ret < 0) {
1112 goto fail;
1113 }
1114 goto success;
1115 }
1116 qemu_co_mutex_lock(&s->lock);
1117 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1118 qemu_co_mutex_unlock(&s->lock);
1119 if (ret < 0) {
1120 goto fail;
1121 }
1122 if (cluster_offset == 0) {
1123 ret = -EIO;
1124 goto fail;
1125 }
1126 cluster_offset &= s->cluster_offset_mask;
1127
1128 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1129 ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1130 if (ret < 0) {
1131 goto fail;
1132 }
1133 success:
1134 ret = 0;
1135 fail:
1136 qemu_vfree(buf);
1137 g_free(out_buf);
1138 return ret;
1139 }
1140
1141 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1142 {
1143 BDRVQcowState *s = bs->opaque;
1144 bdi->cluster_size = s->cluster_size;
1145 return 0;
1146 }
1147
1148 static QemuOptsList qcow_create_opts = {
1149 .name = "qcow-create-opts",
1150 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1151 .desc = {
1152 {
1153 .name = BLOCK_OPT_SIZE,
1154 .type = QEMU_OPT_SIZE,
1155 .help = "Virtual disk size"
1156 },
1157 {
1158 .name = BLOCK_OPT_BACKING_FILE,
1159 .type = QEMU_OPT_STRING,
1160 .help = "File name of a base image"
1161 },
1162 {
1163 .name = BLOCK_OPT_BACKING_FMT,
1164 .type = QEMU_OPT_STRING,
1165 .help = "Format of the backing image",
1166 },
1167 {
1168 .name = BLOCK_OPT_ENCRYPT,
1169 .type = QEMU_OPT_BOOL,
1170 .help = "Encrypt the image with format 'aes'. (Deprecated "
1171 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1172 },
1173 {
1174 .name = BLOCK_OPT_ENCRYPT_FORMAT,
1175 .type = QEMU_OPT_STRING,
1176 .help = "Encrypt the image, format choices: 'aes'",
1177 },
1178 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1179 { /* end of list */ }
1180 }
1181 };
1182
1183 static const char *const qcow_strong_runtime_opts[] = {
1184 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1185
1186 NULL
1187 };
1188
1189 static BlockDriver bdrv_qcow = {
1190 .format_name = "qcow",
1191 .instance_size = sizeof(BDRVQcowState),
1192 .bdrv_probe = qcow_probe,
1193 .bdrv_open = qcow_open,
1194 .bdrv_close = qcow_close,
1195 .bdrv_child_perm = bdrv_default_perms,
1196 .bdrv_reopen_prepare = qcow_reopen_prepare,
1197 .bdrv_co_create = qcow_co_create,
1198 .bdrv_co_create_opts = qcow_co_create_opts,
1199 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1200 .is_format = true,
1201 .supports_backing = true,
1202 .bdrv_refresh_limits = qcow_refresh_limits,
1203
1204 .bdrv_co_preadv = qcow_co_preadv,
1205 .bdrv_co_pwritev = qcow_co_pwritev,
1206 .bdrv_co_block_status = qcow_co_block_status,
1207
1208 .bdrv_make_empty = qcow_make_empty,
1209 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1210 .bdrv_get_info = qcow_get_info,
1211
1212 .create_opts = &qcow_create_opts,
1213 .strong_runtime_opts = qcow_strong_runtime_opts,
1214 };
1215
1216 static void bdrv_qcow_init(void)
1217 {
1218 bdrv_register(&bdrv_qcow);
1219 }
1220
1221 block_init(bdrv_qcow_init);
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