Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging
[qemu/ar7.git] / block / qcow.c
blobf8919a44d1935b18b545bbd8bbf4a007d000d75a
1 /*
2 * Block driver for the QCOW format
4 * Copyright (c) 2004-2006 Fabrice Bellard
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:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
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.
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"
44 /**************************************************************/
45 /* QEMU COW block driver with compression and encryption support */
47 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
48 #define QCOW_VERSION 1
50 #define QCOW_CRYPT_NONE 0
51 #define QCOW_CRYPT_AES 1
53 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
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;
69 #define L2_CACHE_SIZE 16
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;
92 static QemuOptsList qcow_create_opts;
94 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
96 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
98 const QCowHeader *cow_header = (const void *)buf;
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;
108 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
109 Error **errp)
111 BDRVQcowState *s = bs->opaque;
112 unsigned int len, i, shift;
113 int ret;
114 QCowHeader header;
115 QCryptoBlockOpenOptions *crypto_opts = NULL;
116 unsigned int cflags = 0;
117 QDict *encryptopts = NULL;
118 const char *encryptfmt;
120 qdict_extract_subqdict(options, &encryptopts, "encrypt.");
121 encryptfmt = qdict_get_try_str(encryptopts, "format");
123 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
124 BDRV_CHILD_IMAGE, false, errp);
125 if (!bs->file) {
126 ret = -EINVAL;
127 goto fail;
130 ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
131 if (ret < 0) {
132 goto fail;
134 header.magic = be32_to_cpu(header.magic);
135 header.version = be32_to_cpu(header.version);
136 header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
137 header.backing_file_size = be32_to_cpu(header.backing_file_size);
138 header.mtime = be32_to_cpu(header.mtime);
139 header.size = be64_to_cpu(header.size);
140 header.crypt_method = be32_to_cpu(header.crypt_method);
141 header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
143 if (header.magic != QCOW_MAGIC) {
144 error_setg(errp, "Image not in qcow format");
145 ret = -EINVAL;
146 goto fail;
148 if (header.version != QCOW_VERSION) {
149 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32,
150 QCOW_VERSION, header.version);
151 if (header.version == 2 || header.version == 3) {
152 error_append_hint(errp, "Try the 'qcow2' driver instead.\n");
155 ret = -ENOTSUP;
156 goto fail;
159 if (header.size <= 1) {
160 error_setg(errp, "Image size is too small (must be at least 2 bytes)");
161 ret = -EINVAL;
162 goto fail;
164 if (header.cluster_bits < 9 || header.cluster_bits > 16) {
165 error_setg(errp, "Cluster size must be between 512 and 64k");
166 ret = -EINVAL;
167 goto fail;
170 /* l2_bits specifies number of entries; storing a uint64_t in each entry,
171 * so bytes = num_entries << 3. */
172 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
173 error_setg(errp, "L2 table size must be between 512 and 64k");
174 ret = -EINVAL;
175 goto fail;
178 s->crypt_method_header = header.crypt_method;
179 if (s->crypt_method_header) {
180 if (bdrv_uses_whitelist() &&
181 s->crypt_method_header == QCOW_CRYPT_AES) {
182 error_setg(errp,
183 "Use of AES-CBC encrypted qcow images is no longer "
184 "supported in system emulators");
185 error_append_hint(errp,
186 "You can use 'qemu-img convert' to convert your "
187 "image to an alternative supported format, such "
188 "as unencrypted qcow, or raw with the LUKS "
189 "format instead.\n");
190 ret = -ENOSYS;
191 goto fail;
193 if (s->crypt_method_header == QCOW_CRYPT_AES) {
194 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
195 error_setg(errp,
196 "Header reported 'aes' encryption format but "
197 "options specify '%s'", encryptfmt);
198 ret = -EINVAL;
199 goto fail;
201 qdict_put_str(encryptopts, "format", "qcow");
202 crypto_opts = block_crypto_open_opts_init(encryptopts, errp);
203 if (!crypto_opts) {
204 ret = -EINVAL;
205 goto fail;
208 if (flags & BDRV_O_NO_IO) {
209 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
211 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
212 NULL, NULL, cflags, 1, errp);
213 if (!s->crypto) {
214 ret = -EINVAL;
215 goto fail;
217 } else {
218 error_setg(errp, "invalid encryption method in qcow header");
219 ret = -EINVAL;
220 goto fail;
222 bs->encrypted = true;
223 } else {
224 if (encryptfmt) {
225 error_setg(errp, "No encryption in image header, but options "
226 "specified format '%s'", encryptfmt);
227 ret = -EINVAL;
228 goto fail;
231 s->cluster_bits = header.cluster_bits;
232 s->cluster_size = 1 << s->cluster_bits;
233 s->l2_bits = header.l2_bits;
234 s->l2_size = 1 << s->l2_bits;
235 bs->total_sectors = header.size / 512;
236 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
238 /* read the level 1 table */
239 shift = s->cluster_bits + s->l2_bits;
240 if (header.size > UINT64_MAX - (1LL << shift)) {
241 error_setg(errp, "Image too large");
242 ret = -EINVAL;
243 goto fail;
244 } else {
245 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
246 if (l1_size > INT_MAX / sizeof(uint64_t)) {
247 error_setg(errp, "Image too large");
248 ret = -EINVAL;
249 goto fail;
251 s->l1_size = l1_size;
254 s->l1_table_offset = header.l1_table_offset;
255 s->l1_table = g_try_new(uint64_t, s->l1_size);
256 if (s->l1_table == NULL) {
257 error_setg(errp, "Could not allocate memory for L1 table");
258 ret = -ENOMEM;
259 goto fail;
262 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
263 s->l1_size * sizeof(uint64_t));
264 if (ret < 0) {
265 goto fail;
268 for(i = 0;i < s->l1_size; i++) {
269 s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
272 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
273 s->l2_cache =
274 qemu_try_blockalign(bs->file->bs,
275 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
276 if (s->l2_cache == NULL) {
277 error_setg(errp, "Could not allocate L2 table cache");
278 ret = -ENOMEM;
279 goto fail;
281 s->cluster_cache = g_malloc(s->cluster_size);
282 s->cluster_data = g_malloc(s->cluster_size);
283 s->cluster_cache_offset = -1;
285 /* read the backing file name */
286 if (header.backing_file_offset != 0) {
287 len = header.backing_file_size;
288 if (len > 1023 || len >= sizeof(bs->backing_file)) {
289 error_setg(errp, "Backing file name too long");
290 ret = -EINVAL;
291 goto fail;
293 ret = bdrv_pread(bs->file, header.backing_file_offset,
294 bs->auto_backing_file, len);
295 if (ret < 0) {
296 goto fail;
298 bs->auto_backing_file[len] = '\0';
299 pstrcpy(bs->backing_file, sizeof(bs->backing_file),
300 bs->auto_backing_file);
303 /* Disable migration when qcow images are used */
304 error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
305 "does not support live migration",
306 bdrv_get_device_or_node_name(bs));
307 ret = migrate_add_blocker(s->migration_blocker, errp);
308 if (ret < 0) {
309 error_free(s->migration_blocker);
310 goto fail;
313 qobject_unref(encryptopts);
314 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
315 qemu_co_mutex_init(&s->lock);
316 return 0;
318 fail:
319 g_free(s->l1_table);
320 qemu_vfree(s->l2_cache);
321 g_free(s->cluster_cache);
322 g_free(s->cluster_data);
323 qcrypto_block_free(s->crypto);
324 qobject_unref(encryptopts);
325 qapi_free_QCryptoBlockOpenOptions(crypto_opts);
326 return ret;
330 /* We have nothing to do for QCOW reopen, stubs just return
331 * success */
332 static int qcow_reopen_prepare(BDRVReopenState *state,
333 BlockReopenQueue *queue, Error **errp)
335 return 0;
339 /* 'allocate' is:
341 * 0 to not allocate.
343 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
344 * to 'n_end' within the cluster)
346 * 2 to allocate a compressed cluster of size
347 * 'compressed_size'. 'compressed_size' must be > 0 and <
348 * cluster_size
350 * return 0 if not allocated, 1 if *result is assigned, and negative
351 * errno on failure.
353 static int get_cluster_offset(BlockDriverState *bs,
354 uint64_t offset, int allocate,
355 int compressed_size,
356 int n_start, int n_end, uint64_t *result)
358 BDRVQcowState *s = bs->opaque;
359 int min_index, i, j, l1_index, l2_index, ret;
360 int64_t l2_offset;
361 uint64_t *l2_table, cluster_offset, tmp;
362 uint32_t min_count;
363 int new_l2_table;
365 *result = 0;
366 l1_index = offset >> (s->l2_bits + s->cluster_bits);
367 l2_offset = s->l1_table[l1_index];
368 new_l2_table = 0;
369 if (!l2_offset) {
370 if (!allocate)
371 return 0;
372 /* allocate a new l2 entry */
373 l2_offset = bdrv_getlength(bs->file->bs);
374 if (l2_offset < 0) {
375 return l2_offset;
377 /* round to cluster size */
378 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
379 /* update the L1 entry */
380 s->l1_table[l1_index] = l2_offset;
381 tmp = cpu_to_be64(l2_offset);
382 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
383 ret = bdrv_pwrite_sync(bs->file,
384 s->l1_table_offset + l1_index * sizeof(tmp),
385 &tmp, sizeof(tmp));
386 if (ret < 0) {
387 return ret;
389 new_l2_table = 1;
391 for(i = 0; i < L2_CACHE_SIZE; i++) {
392 if (l2_offset == s->l2_cache_offsets[i]) {
393 /* increment the hit count */
394 if (++s->l2_cache_counts[i] == 0xffffffff) {
395 for(j = 0; j < L2_CACHE_SIZE; j++) {
396 s->l2_cache_counts[j] >>= 1;
399 l2_table = s->l2_cache + (i << s->l2_bits);
400 goto found;
403 /* not found: load a new entry in the least used one */
404 min_index = 0;
405 min_count = 0xffffffff;
406 for(i = 0; i < L2_CACHE_SIZE; i++) {
407 if (s->l2_cache_counts[i] < min_count) {
408 min_count = s->l2_cache_counts[i];
409 min_index = i;
412 l2_table = s->l2_cache + (min_index << s->l2_bits);
413 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
414 if (new_l2_table) {
415 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
416 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
417 s->l2_size * sizeof(uint64_t));
418 if (ret < 0) {
419 return ret;
421 } else {
422 ret = bdrv_pread(bs->file, l2_offset, l2_table,
423 s->l2_size * sizeof(uint64_t));
424 if (ret < 0) {
425 return ret;
428 s->l2_cache_offsets[min_index] = l2_offset;
429 s->l2_cache_counts[min_index] = 1;
430 found:
431 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
432 cluster_offset = be64_to_cpu(l2_table[l2_index]);
433 if (!cluster_offset ||
434 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
435 if (!allocate)
436 return 0;
437 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
438 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
439 /* allocate a new cluster */
440 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
441 (n_end - n_start) < s->cluster_size) {
442 /* if the cluster is already compressed, we must
443 decompress it in the case it is not completely
444 overwritten */
445 if (decompress_cluster(bs, cluster_offset) < 0) {
446 return -EIO;
448 cluster_offset = bdrv_getlength(bs->file->bs);
449 if ((int64_t) cluster_offset < 0) {
450 return cluster_offset;
452 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
453 /* write the cluster content */
454 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
455 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache,
456 s->cluster_size);
457 if (ret < 0) {
458 return ret;
460 } else {
461 cluster_offset = bdrv_getlength(bs->file->bs);
462 if ((int64_t) cluster_offset < 0) {
463 return cluster_offset;
465 if (allocate == 1) {
466 /* round to cluster size */
467 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
468 if (cluster_offset + s->cluster_size > INT64_MAX) {
469 return -E2BIG;
471 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size,
472 false, PREALLOC_MODE_OFF, 0, NULL);
473 if (ret < 0) {
474 return ret;
476 /* if encrypted, we must initialize the cluster
477 content which won't be written */
478 if (bs->encrypted &&
479 (n_end - n_start) < s->cluster_size) {
480 uint64_t start_offset;
481 assert(s->crypto);
482 start_offset = offset & ~(s->cluster_size - 1);
483 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
484 if (i < n_start || i >= n_end) {
485 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
486 if (qcrypto_block_encrypt(s->crypto,
487 start_offset + i,
488 s->cluster_data,
489 BDRV_SECTOR_SIZE,
490 NULL) < 0) {
491 return -EIO;
493 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
494 ret = bdrv_pwrite(bs->file,
495 cluster_offset + i,
496 s->cluster_data,
497 BDRV_SECTOR_SIZE);
498 if (ret < 0) {
499 return ret;
504 } else if (allocate == 2) {
505 cluster_offset |= QCOW_OFLAG_COMPRESSED |
506 (uint64_t)compressed_size << (63 - s->cluster_bits);
509 /* update L2 table */
510 tmp = cpu_to_be64(cluster_offset);
511 l2_table[l2_index] = tmp;
512 if (allocate == 2) {
513 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
514 } else {
515 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
517 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
518 &tmp, sizeof(tmp));
519 if (ret < 0) {
520 return ret;
523 *result = cluster_offset;
524 return 1;
527 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs,
528 bool want_zero,
529 int64_t offset, int64_t bytes,
530 int64_t *pnum, int64_t *map,
531 BlockDriverState **file)
533 BDRVQcowState *s = bs->opaque;
534 int index_in_cluster, ret;
535 int64_t n;
536 uint64_t cluster_offset;
538 qemu_co_mutex_lock(&s->lock);
539 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
540 qemu_co_mutex_unlock(&s->lock);
541 if (ret < 0) {
542 return ret;
544 index_in_cluster = offset & (s->cluster_size - 1);
545 n = s->cluster_size - index_in_cluster;
546 if (n > bytes) {
547 n = bytes;
549 *pnum = n;
550 if (!cluster_offset) {
551 return 0;
553 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) {
554 return BDRV_BLOCK_DATA;
556 *map = cluster_offset | index_in_cluster;
557 *file = bs->file->bs;
558 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
561 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
562 const uint8_t *buf, int buf_size)
564 z_stream strm1, *strm = &strm1;
565 int ret, out_len;
567 memset(strm, 0, sizeof(*strm));
569 strm->next_in = (uint8_t *)buf;
570 strm->avail_in = buf_size;
571 strm->next_out = out_buf;
572 strm->avail_out = out_buf_size;
574 ret = inflateInit2(strm, -12);
575 if (ret != Z_OK)
576 return -1;
577 ret = inflate(strm, Z_FINISH);
578 out_len = strm->next_out - out_buf;
579 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
580 out_len != out_buf_size) {
581 inflateEnd(strm);
582 return -1;
584 inflateEnd(strm);
585 return 0;
588 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
590 BDRVQcowState *s = bs->opaque;
591 int ret, csize;
592 uint64_t coffset;
594 coffset = cluster_offset & s->cluster_offset_mask;
595 if (s->cluster_cache_offset != coffset) {
596 csize = cluster_offset >> (63 - s->cluster_bits);
597 csize &= (s->cluster_size - 1);
598 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
599 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
600 if (ret != csize)
601 return -1;
602 if (decompress_buffer(s->cluster_cache, s->cluster_size,
603 s->cluster_data, csize) < 0) {
604 return -1;
606 s->cluster_cache_offset = coffset;
608 return 0;
611 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
613 /* At least encrypted images require 512-byte alignment. Apply the
614 * limit universally, rather than just on encrypted images, as
615 * it's easier to let the block layer handle rounding than to
616 * audit this code further. */
617 bs->bl.request_alignment = BDRV_SECTOR_SIZE;
620 static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset,
621 uint64_t bytes, QEMUIOVector *qiov,
622 int flags)
624 BDRVQcowState *s = bs->opaque;
625 int offset_in_cluster;
626 int ret = 0, n;
627 uint64_t cluster_offset;
628 uint8_t *buf;
629 void *orig_buf;
631 assert(!flags);
632 if (qiov->niov > 1) {
633 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
634 if (buf == NULL) {
635 return -ENOMEM;
637 } else {
638 orig_buf = NULL;
639 buf = (uint8_t *)qiov->iov->iov_base;
642 qemu_co_mutex_lock(&s->lock);
644 while (bytes != 0) {
645 /* prepare next request */
646 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
647 if (ret < 0) {
648 break;
650 offset_in_cluster = offset & (s->cluster_size - 1);
651 n = s->cluster_size - offset_in_cluster;
652 if (n > bytes) {
653 n = bytes;
656 if (!cluster_offset) {
657 if (bs->backing) {
658 /* read from the base image */
659 qemu_co_mutex_unlock(&s->lock);
660 /* qcow2 emits this on bs->file instead of bs->backing */
661 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
662 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
663 qemu_co_mutex_lock(&s->lock);
664 if (ret < 0) {
665 break;
667 } else {
668 /* Note: in this case, no need to wait */
669 memset(buf, 0, n);
671 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
672 /* add AIO support for compressed blocks ? */
673 if (decompress_cluster(bs, cluster_offset) < 0) {
674 ret = -EIO;
675 break;
677 memcpy(buf, s->cluster_cache + offset_in_cluster, n);
678 } else {
679 if ((cluster_offset & 511) != 0) {
680 ret = -EIO;
681 break;
683 qemu_co_mutex_unlock(&s->lock);
684 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
685 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
686 n, buf, 0);
687 qemu_co_mutex_lock(&s->lock);
688 if (ret < 0) {
689 break;
691 if (bs->encrypted) {
692 assert(s->crypto);
693 if (qcrypto_block_decrypt(s->crypto,
694 offset, buf, n, NULL) < 0) {
695 ret = -EIO;
696 break;
700 ret = 0;
702 bytes -= n;
703 offset += n;
704 buf += n;
707 qemu_co_mutex_unlock(&s->lock);
709 if (qiov->niov > 1) {
710 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
711 qemu_vfree(orig_buf);
714 return ret;
717 static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, uint64_t offset,
718 uint64_t bytes, QEMUIOVector *qiov,
719 int flags)
721 BDRVQcowState *s = bs->opaque;
722 int offset_in_cluster;
723 uint64_t cluster_offset;
724 int ret = 0, n;
725 uint8_t *buf;
726 void *orig_buf;
728 assert(!flags);
729 s->cluster_cache_offset = -1; /* disable compressed cache */
731 /* We must always copy the iov when encrypting, so we
732 * don't modify the original data buffer during encryption */
733 if (bs->encrypted || qiov->niov > 1) {
734 buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
735 if (buf == NULL) {
736 return -ENOMEM;
738 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
739 } else {
740 orig_buf = NULL;
741 buf = (uint8_t *)qiov->iov->iov_base;
744 qemu_co_mutex_lock(&s->lock);
746 while (bytes != 0) {
747 offset_in_cluster = offset & (s->cluster_size - 1);
748 n = s->cluster_size - offset_in_cluster;
749 if (n > bytes) {
750 n = bytes;
752 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
753 offset_in_cluster + n, &cluster_offset);
754 if (ret < 0) {
755 break;
757 if (!cluster_offset || (cluster_offset & 511) != 0) {
758 ret = -EIO;
759 break;
761 if (bs->encrypted) {
762 assert(s->crypto);
763 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
764 ret = -EIO;
765 break;
769 qemu_co_mutex_unlock(&s->lock);
770 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
771 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
772 n, buf, 0);
773 qemu_co_mutex_lock(&s->lock);
774 if (ret < 0) {
775 break;
777 ret = 0;
779 bytes -= n;
780 offset += n;
781 buf += n;
783 qemu_co_mutex_unlock(&s->lock);
785 qemu_vfree(orig_buf);
787 return ret;
790 static void qcow_close(BlockDriverState *bs)
792 BDRVQcowState *s = bs->opaque;
794 qcrypto_block_free(s->crypto);
795 s->crypto = NULL;
796 g_free(s->l1_table);
797 qemu_vfree(s->l2_cache);
798 g_free(s->cluster_cache);
799 g_free(s->cluster_data);
801 migrate_del_blocker(s->migration_blocker);
802 error_free(s->migration_blocker);
805 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts,
806 Error **errp)
808 BlockdevCreateOptionsQcow *qcow_opts;
809 int header_size, backing_filename_len, l1_size, shift, i;
810 QCowHeader header;
811 uint8_t *tmp;
812 int64_t total_size = 0;
813 int ret;
814 BlockDriverState *bs;
815 BlockBackend *qcow_blk;
816 QCryptoBlock *crypto = NULL;
818 assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
819 qcow_opts = &opts->u.qcow;
821 /* Sanity checks */
822 total_size = qcow_opts->size;
823 if (total_size == 0) {
824 error_setg(errp, "Image size is too small, cannot be zero length");
825 return -EINVAL;
828 if (qcow_opts->has_encrypt &&
829 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
831 error_setg(errp, "Unsupported encryption format");
832 return -EINVAL;
835 /* Create BlockBackend to write to the image */
836 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp);
837 if (bs == NULL) {
838 return -EIO;
841 qcow_blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
842 BLK_PERM_ALL, errp);
843 if (!qcow_blk) {
844 ret = -EPERM;
845 goto exit;
847 blk_set_allow_write_beyond_eof(qcow_blk, true);
849 /* Create image format */
850 memset(&header, 0, sizeof(header));
851 header.magic = cpu_to_be32(QCOW_MAGIC);
852 header.version = cpu_to_be32(QCOW_VERSION);
853 header.size = cpu_to_be64(total_size);
854 header_size = sizeof(header);
855 backing_filename_len = 0;
856 if (qcow_opts->has_backing_file) {
857 if (strcmp(qcow_opts->backing_file, "fat:")) {
858 header.backing_file_offset = cpu_to_be64(header_size);
859 backing_filename_len = strlen(qcow_opts->backing_file);
860 header.backing_file_size = cpu_to_be32(backing_filename_len);
861 header_size += backing_filename_len;
862 } else {
863 /* special backing file for vvfat */
864 qcow_opts->has_backing_file = false;
866 header.cluster_bits = 9; /* 512 byte cluster to avoid copying
867 unmodified sectors */
868 header.l2_bits = 12; /* 32 KB L2 tables */
869 } else {
870 header.cluster_bits = 12; /* 4 KB clusters */
871 header.l2_bits = 9; /* 4 KB L2 tables */
873 header_size = (header_size + 7) & ~7;
874 shift = header.cluster_bits + header.l2_bits;
875 l1_size = (total_size + (1LL << shift) - 1) >> shift;
877 header.l1_table_offset = cpu_to_be64(header_size);
879 if (qcow_opts->has_encrypt) {
880 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
882 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
883 NULL, NULL, NULL, errp);
884 if (!crypto) {
885 ret = -EINVAL;
886 goto exit;
888 } else {
889 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
892 /* write all the data */
893 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0);
894 if (ret != sizeof(header)) {
895 goto exit;
898 if (qcow_opts->has_backing_file) {
899 ret = blk_pwrite(qcow_blk, sizeof(header),
900 qcow_opts->backing_file, backing_filename_len, 0);
901 if (ret != backing_filename_len) {
902 goto exit;
906 tmp = g_malloc0(BDRV_SECTOR_SIZE);
907 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
908 i++) {
909 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
910 tmp, BDRV_SECTOR_SIZE, 0);
911 if (ret != BDRV_SECTOR_SIZE) {
912 g_free(tmp);
913 goto exit;
917 g_free(tmp);
918 ret = 0;
919 exit:
920 blk_unref(qcow_blk);
921 bdrv_unref(bs);
922 qcrypto_block_free(crypto);
923 return ret;
926 static int coroutine_fn qcow_co_create_opts(BlockDriver *drv,
927 const char *filename,
928 QemuOpts *opts, Error **errp)
930 BlockdevCreateOptions *create_options = NULL;
931 BlockDriverState *bs = NULL;
932 QDict *qdict = NULL;
933 Visitor *v;
934 const char *val;
935 int ret;
936 char *backing_fmt;
938 static const QDictRenames opt_renames[] = {
939 { BLOCK_OPT_BACKING_FILE, "backing-file" },
940 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT },
941 { NULL, NULL },
945 * We can't actually store a backing format, but can check that
946 * the user's request made sense.
948 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
949 if (backing_fmt && !bdrv_find_format(backing_fmt)) {
950 error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
951 ret = -EINVAL;
952 goto fail;
955 /* Parse options and convert legacy syntax */
956 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
958 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
959 if (val && !strcmp(val, "on")) {
960 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
961 } else if (val && !strcmp(val, "off")) {
962 qdict_del(qdict, BLOCK_OPT_ENCRYPT);
965 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
966 if (val && !strcmp(val, "aes")) {
967 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
970 if (!qdict_rename_keys(qdict, opt_renames, errp)) {
971 ret = -EINVAL;
972 goto fail;
975 /* Create and open the file (protocol layer) */
976 ret = bdrv_create_file(filename, opts, errp);
977 if (ret < 0) {
978 goto fail;
981 bs = bdrv_open(filename, NULL, NULL,
982 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
983 if (bs == NULL) {
984 ret = -EIO;
985 goto fail;
988 /* Now get the QAPI type BlockdevCreateOptions */
989 qdict_put_str(qdict, "driver", "qcow");
990 qdict_put_str(qdict, "file", bs->node_name);
992 v = qobject_input_visitor_new_flat_confused(qdict, errp);
993 if (!v) {
994 ret = -EINVAL;
995 goto fail;
998 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
999 visit_free(v);
1000 if (!create_options) {
1001 ret = -EINVAL;
1002 goto fail;
1005 /* Silently round up size */
1006 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1007 create_options->u.qcow.size =
1008 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1010 /* Create the qcow image (format layer) */
1011 ret = qcow_co_create(create_options, errp);
1012 if (ret < 0) {
1013 goto fail;
1016 ret = 0;
1017 fail:
1018 g_free(backing_fmt);
1019 qobject_unref(qdict);
1020 bdrv_unref(bs);
1021 qapi_free_BlockdevCreateOptions(create_options);
1022 return ret;
1025 static int qcow_make_empty(BlockDriverState *bs)
1027 BDRVQcowState *s = bs->opaque;
1028 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1029 int ret;
1031 memset(s->l1_table, 0, l1_length);
1032 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
1033 l1_length) < 0)
1034 return -1;
1035 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1036 PREALLOC_MODE_OFF, 0, NULL);
1037 if (ret < 0)
1038 return ret;
1040 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1041 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1042 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1044 return 0;
1047 /* XXX: put compressed sectors first, then all the cluster aligned
1048 tables to avoid losing bytes in alignment */
1049 static coroutine_fn int
1050 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
1051 uint64_t bytes, QEMUIOVector *qiov)
1053 BDRVQcowState *s = bs->opaque;
1054 z_stream strm;
1055 int ret, out_len;
1056 uint8_t *buf, *out_buf;
1057 uint64_t cluster_offset;
1059 buf = qemu_blockalign(bs, s->cluster_size);
1060 if (bytes != s->cluster_size) {
1061 if (bytes > s->cluster_size ||
1062 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1064 qemu_vfree(buf);
1065 return -EINVAL;
1067 /* Zero-pad last write if image size is not cluster aligned */
1068 memset(buf + bytes, 0, s->cluster_size - bytes);
1070 qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1072 out_buf = g_malloc(s->cluster_size);
1074 /* best compression, small window, no zlib header */
1075 memset(&strm, 0, sizeof(strm));
1076 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1077 Z_DEFLATED, -12,
1078 9, Z_DEFAULT_STRATEGY);
1079 if (ret != 0) {
1080 ret = -EINVAL;
1081 goto fail;
1084 strm.avail_in = s->cluster_size;
1085 strm.next_in = (uint8_t *)buf;
1086 strm.avail_out = s->cluster_size;
1087 strm.next_out = out_buf;
1089 ret = deflate(&strm, Z_FINISH);
1090 if (ret != Z_STREAM_END && ret != Z_OK) {
1091 deflateEnd(&strm);
1092 ret = -EINVAL;
1093 goto fail;
1095 out_len = strm.next_out - out_buf;
1097 deflateEnd(&strm);
1099 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1100 /* could not compress: write normal cluster */
1101 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1102 if (ret < 0) {
1103 goto fail;
1105 goto success;
1107 qemu_co_mutex_lock(&s->lock);
1108 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1109 qemu_co_mutex_unlock(&s->lock);
1110 if (ret < 0) {
1111 goto fail;
1113 if (cluster_offset == 0) {
1114 ret = -EIO;
1115 goto fail;
1117 cluster_offset &= s->cluster_offset_mask;
1119 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1120 ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1121 if (ret < 0) {
1122 goto fail;
1124 success:
1125 ret = 0;
1126 fail:
1127 qemu_vfree(buf);
1128 g_free(out_buf);
1129 return ret;
1132 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1134 BDRVQcowState *s = bs->opaque;
1135 bdi->cluster_size = s->cluster_size;
1136 return 0;
1139 static QemuOptsList qcow_create_opts = {
1140 .name = "qcow-create-opts",
1141 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1142 .desc = {
1144 .name = BLOCK_OPT_SIZE,
1145 .type = QEMU_OPT_SIZE,
1146 .help = "Virtual disk size"
1149 .name = BLOCK_OPT_BACKING_FILE,
1150 .type = QEMU_OPT_STRING,
1151 .help = "File name of a base image"
1154 .name = BLOCK_OPT_BACKING_FMT,
1155 .type = QEMU_OPT_STRING,
1156 .help = "Format of the backing image",
1159 .name = BLOCK_OPT_ENCRYPT,
1160 .type = QEMU_OPT_BOOL,
1161 .help = "Encrypt the image with format 'aes'. (Deprecated "
1162 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1165 .name = BLOCK_OPT_ENCRYPT_FORMAT,
1166 .type = QEMU_OPT_STRING,
1167 .help = "Encrypt the image, format choices: 'aes'",
1169 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1170 { /* end of list */ }
1174 static const char *const qcow_strong_runtime_opts[] = {
1175 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1177 NULL
1180 static BlockDriver bdrv_qcow = {
1181 .format_name = "qcow",
1182 .instance_size = sizeof(BDRVQcowState),
1183 .bdrv_probe = qcow_probe,
1184 .bdrv_open = qcow_open,
1185 .bdrv_close = qcow_close,
1186 .bdrv_child_perm = bdrv_default_perms,
1187 .bdrv_reopen_prepare = qcow_reopen_prepare,
1188 .bdrv_co_create = qcow_co_create,
1189 .bdrv_co_create_opts = qcow_co_create_opts,
1190 .bdrv_has_zero_init = bdrv_has_zero_init_1,
1191 .is_format = true,
1192 .supports_backing = true,
1193 .bdrv_refresh_limits = qcow_refresh_limits,
1195 .bdrv_co_preadv = qcow_co_preadv,
1196 .bdrv_co_pwritev = qcow_co_pwritev,
1197 .bdrv_co_block_status = qcow_co_block_status,
1199 .bdrv_make_empty = qcow_make_empty,
1200 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1201 .bdrv_get_info = qcow_get_info,
1203 .create_opts = &qcow_create_opts,
1204 .strong_runtime_opts = qcow_strong_runtime_opts,
1207 static void bdrv_qcow_init(void)
1209 bdrv_register(&bdrv_qcow);
1212 block_init(bdrv_qcow_init);