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-common.h"
25 #include "block_int.h"
26 #include <zlib.h>
27 #include "aes.h"
28 #include <assert.h>
29
30 /*
31 Differences with QCOW:
32
33 - Support for multiple incremental snapshots.
34 - Memory management by reference counts.
35 - Clusters which have a reference count of one have the bit
36 QCOW_OFLAG_COPIED to optimize write performance.
37 - Size of compressed clusters is stored in sectors to reduce bit usage
38 in the cluster offsets.
39 - Support for storing additional data (such as the VM state) in the
40 snapshots.
41 - If a backing store is used, the cluster size is not constrained
42 (could be backported to QCOW).
43 - L2 tables have always a size of one cluster.
44 */
45
46 //#define DEBUG_ALLOC
47 //#define DEBUG_ALLOC2
48
49 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
50 #define QCOW_VERSION 2
51
52 #define QCOW_CRYPT_NONE 0
53 #define QCOW_CRYPT_AES 1
54
55 #define QCOW_MAX_CRYPT_CLUSTERS 32
56
57 /* indicate that the refcount of the referenced cluster is exactly one. */
58 #define QCOW_OFLAG_COPIED (1LL << 63)
59 /* indicate that the cluster is compressed (they never have the copied flag) */
60 #define QCOW_OFLAG_COMPRESSED (1LL << 62)
61
62 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
63
64 typedef struct QCowHeader {
65 uint32_t magic;
66 uint32_t version;
67 uint64_t backing_file_offset;
68 uint32_t backing_file_size;
69 uint32_t cluster_bits;
70 uint64_t size; /* in bytes */
71 uint32_t crypt_method;
72 uint32_t l1_size; /* XXX: save number of clusters instead ? */
73 uint64_t l1_table_offset;
74 uint64_t refcount_table_offset;
75 uint32_t refcount_table_clusters;
76 uint32_t nb_snapshots;
77 uint64_t snapshots_offset;
78 } QCowHeader;
79
80 typedef struct __attribute__((packed)) QCowSnapshotHeader {
81 /* header is 8 byte aligned */
82 uint64_t l1_table_offset;
83
84 uint32_t l1_size;
85 uint16_t id_str_size;
86 uint16_t name_size;
87
88 uint32_t date_sec;
89 uint32_t date_nsec;
90
91 uint64_t vm_clock_nsec;
92
93 uint32_t vm_state_size;
94 uint32_t extra_data_size; /* for extension */
95 /* extra data follows */
96 /* id_str follows */
97 /* name follows */
98 } QCowSnapshotHeader;
99
100 #define L2_CACHE_SIZE 16
101
102 typedef struct QCowSnapshot {
103 uint64_t l1_table_offset;
104 uint32_t l1_size;
105 char *id_str;
106 char *name;
107 uint32_t vm_state_size;
108 uint32_t date_sec;
109 uint32_t date_nsec;
110 uint64_t vm_clock_nsec;
111 } QCowSnapshot;
112
113 typedef struct BDRVQcowState {
114 BlockDriverState *hd;
115 int cluster_bits;
116 int cluster_size;
117 int cluster_sectors;
118 int l2_bits;
119 int l2_size;
120 int l1_size;
121 int l1_vm_state_index;
122 int csize_shift;
123 int csize_mask;
124 uint64_t cluster_offset_mask;
125 uint64_t l1_table_offset;
126 uint64_t *l1_table;
127 uint64_t *l2_cache;
128 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
129 uint32_t l2_cache_counts[L2_CACHE_SIZE];
130 uint8_t *cluster_cache;
131 uint8_t *cluster_data;
132 uint64_t cluster_cache_offset;
133
134 uint64_t *refcount_table;
135 uint64_t refcount_table_offset;
136 uint32_t refcount_table_size;
137 uint64_t refcount_block_cache_offset;
138 uint16_t *refcount_block_cache;
139 int64_t free_cluster_index;
140 int64_t free_byte_offset;
141
142 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
143 uint32_t crypt_method_header;
144 AES_KEY aes_encrypt_key;
145 AES_KEY aes_decrypt_key;
146 uint64_t snapshots_offset;
147 int snapshots_size;
148 int nb_snapshots;
149 QCowSnapshot *snapshots;
150 } BDRVQcowState;
151
152 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
153 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
154 uint8_t *buf, int nb_sectors);
155 static int qcow_read_snapshots(BlockDriverState *bs);
156 static void qcow_free_snapshots(BlockDriverState *bs);
157 static int refcount_init(BlockDriverState *bs);
158 static void refcount_close(BlockDriverState *bs);
159 static int get_refcount(BlockDriverState *bs, int64_t cluster_index);
160 static int update_cluster_refcount(BlockDriverState *bs,
161 int64_t cluster_index,
162 int addend);
163 static void update_refcount(BlockDriverState *bs,
164 int64_t offset, int64_t length,
165 int addend);
166 static int64_t alloc_clusters(BlockDriverState *bs, int64_t size);
167 static int64_t alloc_bytes(BlockDriverState *bs, int size);
168 static void free_clusters(BlockDriverState *bs,
169 int64_t offset, int64_t size);
170 #ifdef DEBUG_ALLOC
171 static void check_refcounts(BlockDriverState *bs);
172 #endif
173
qcow_probe(const uint8_t * buf,int buf_size,const char * filename)174 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
175 {
176 const QCowHeader *cow_header = (const void *)buf;
177
178 if (buf_size >= sizeof(QCowHeader) &&
179 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
180 be32_to_cpu(cow_header->version) == QCOW_VERSION)
181 return 100;
182 else
183 return 0;
184 }
185
qcow_open(BlockDriverState * bs,const char * filename,int flags)186 static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
187 {
188 BDRVQcowState *s = bs->opaque;
189 int len, i, shift, ret;
190 QCowHeader header;
191
192 ret = bdrv_file_open(&s->hd, filename, flags);
193 if (ret < 0)
194 return ret;
195 if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
196 goto fail;
197 be32_to_cpus(&header.magic);
198 be32_to_cpus(&header.version);
199 be64_to_cpus(&header.backing_file_offset);
200 be32_to_cpus(&header.backing_file_size);
201 be64_to_cpus(&header.size);
202 be32_to_cpus(&header.cluster_bits);
203 be32_to_cpus(&header.crypt_method);
204 be64_to_cpus(&header.l1_table_offset);
205 be32_to_cpus(&header.l1_size);
206 be64_to_cpus(&header.refcount_table_offset);
207 be32_to_cpus(&header.refcount_table_clusters);
208 be64_to_cpus(&header.snapshots_offset);
209 be32_to_cpus(&header.nb_snapshots);
210
211 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
212 goto fail;
213 if (header.size <= 1 ||
214 header.cluster_bits < 9 ||
215 header.cluster_bits > 16)
216 goto fail;
217 if (header.crypt_method > QCOW_CRYPT_AES)
218 goto fail;
219 s->crypt_method_header = header.crypt_method;
220 if (s->crypt_method_header)
221 bs->encrypted = 1;
222 s->cluster_bits = header.cluster_bits;
223 s->cluster_size = 1 << s->cluster_bits;
224 s->cluster_sectors = 1 << (s->cluster_bits - 9);
225 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
226 s->l2_size = 1 << s->l2_bits;
227 bs->total_sectors = header.size / 512;
228 s->csize_shift = (62 - (s->cluster_bits - 8));
229 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
230 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
231 s->refcount_table_offset = header.refcount_table_offset;
232 s->refcount_table_size =
233 header.refcount_table_clusters << (s->cluster_bits - 3);
234
235 s->snapshots_offset = header.snapshots_offset;
236 s->nb_snapshots = header.nb_snapshots;
237
238 /* read the level 1 table */
239 s->l1_size = header.l1_size;
240 shift = s->cluster_bits + s->l2_bits;
241 s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift;
242 /* the L1 table must contain at least enough entries to put
243 header.size bytes */
244 if (s->l1_size < s->l1_vm_state_index)
245 goto fail;
246 s->l1_table_offset = header.l1_table_offset;
247 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
248 if (!s->l1_table)
249 goto fail;
250 if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
251 s->l1_size * sizeof(uint64_t))
252 goto fail;
253 for(i = 0;i < s->l1_size; i++) {
254 be64_to_cpus(&s->l1_table[i]);
255 }
256 /* alloc L2 cache */
257 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
258 if (!s->l2_cache)
259 goto fail;
260 s->cluster_cache = qemu_malloc(s->cluster_size);
261 if (!s->cluster_cache)
262 goto fail;
263 /* one more sector for decompressed data alignment */
264 s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
265 + 512);
266 if (!s->cluster_data)
267 goto fail;
268 s->cluster_cache_offset = -1;
269
270 if (refcount_init(bs) < 0)
271 goto fail;
272
273 /* read the backing file name */
274 if (header.backing_file_offset != 0) {
275 len = header.backing_file_size;
276 if (len > 1023)
277 len = 1023;
278 if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
279 goto fail;
280 bs->backing_file[len] = '\0';
281 }
282 if (qcow_read_snapshots(bs) < 0)
283 goto fail;
284
285 #ifdef DEBUG_ALLOC
286 check_refcounts(bs);
287 #endif
288 return 0;
289
290 fail:
291 qcow_free_snapshots(bs);
292 refcount_close(bs);
293 qemu_free(s->l1_table);
294 qemu_free(s->l2_cache);
295 qemu_free(s->cluster_cache);
296 qemu_free(s->cluster_data);
297 bdrv_delete(s->hd);
298 return -1;
299 }
300
qcow_set_key(BlockDriverState * bs,const char * key)301 static int qcow_set_key(BlockDriverState *bs, const char *key)
302 {
303 BDRVQcowState *s = bs->opaque;
304 uint8_t keybuf[16];
305 int len, i;
306
307 memset(keybuf, 0, 16);
308 len = strlen(key);
309 if (len > 16)
310 len = 16;
311 /* XXX: we could compress the chars to 7 bits to increase
312 entropy */
313 for(i = 0;i < len;i++) {
314 keybuf[i] = key[i];
315 }
316 s->crypt_method = s->crypt_method_header;
317
318 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
319 return -1;
320 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
321 return -1;
322 #if 0
323 /* test */
324 {
325 uint8_t in[16];
326 uint8_t out[16];
327 uint8_t tmp[16];
328 for(i=0;i<16;i++)
329 in[i] = i;
330 AES_encrypt(in, tmp, &s->aes_encrypt_key);
331 AES_decrypt(tmp, out, &s->aes_decrypt_key);
332 for(i = 0; i < 16; i++)
333 printf(" %02x", tmp[i]);
334 printf("\n");
335 for(i = 0; i < 16; i++)
336 printf(" %02x", out[i]);
337 printf("\n");
338 }
339 #endif
340 return 0;
341 }
342
343 /* The crypt function is compatible with the linux cryptoloop
344 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
345 supported */
encrypt_sectors(BDRVQcowState * s,int64_t sector_num,uint8_t * out_buf,const uint8_t * in_buf,int nb_sectors,int enc,const AES_KEY * key)346 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
347 uint8_t *out_buf, const uint8_t *in_buf,
348 int nb_sectors, int enc,
349 const AES_KEY *key)
350 {
351 union {
352 uint64_t ll[2];
353 uint8_t b[16];
354 } ivec;
355 int i;
356
357 for(i = 0; i < nb_sectors; i++) {
358 ivec.ll[0] = cpu_to_le64(sector_num);
359 ivec.ll[1] = 0;
360 AES_cbc_encrypt(in_buf, out_buf, 512, key,
361 ivec.b, enc);
362 sector_num++;
363 in_buf += 512;
364 out_buf += 512;
365 }
366 }
367
copy_sectors(BlockDriverState * bs,uint64_t start_sect,uint64_t cluster_offset,int n_start,int n_end)368 static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
369 uint64_t cluster_offset, int n_start, int n_end)
370 {
371 BDRVQcowState *s = bs->opaque;
372 int n, ret;
373
374 n = n_end - n_start;
375 if (n <= 0)
376 return 0;
377 ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
378 if (ret < 0)
379 return ret;
380 if (s->crypt_method) {
381 encrypt_sectors(s, start_sect + n_start,
382 s->cluster_data,
383 s->cluster_data, n, 1,
384 &s->aes_encrypt_key);
385 }
386 ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
387 s->cluster_data, n);
388 if (ret < 0)
389 return ret;
390 return 0;
391 }
392
l2_cache_reset(BlockDriverState * bs)393 static void l2_cache_reset(BlockDriverState *bs)
394 {
395 BDRVQcowState *s = bs->opaque;
396
397 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
398 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
399 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
400 }
401
l2_cache_new_entry(BlockDriverState * bs)402 static inline int l2_cache_new_entry(BlockDriverState *bs)
403 {
404 BDRVQcowState *s = bs->opaque;
405 uint32_t min_count;
406 int min_index, i;
407
408 /* find a new entry in the least used one */
409 min_index = 0;
410 min_count = 0xffffffff;
411 for(i = 0; i < L2_CACHE_SIZE; i++) {
412 if (s->l2_cache_counts[i] < min_count) {
413 min_count = s->l2_cache_counts[i];
414 min_index = i;
415 }
416 }
417 return min_index;
418 }
419
align_offset(int64_t offset,int n)420 static int64_t align_offset(int64_t offset, int n)
421 {
422 offset = (offset + n - 1) & ~(n - 1);
423 return offset;
424 }
425
grow_l1_table(BlockDriverState * bs,int min_size)426 static int grow_l1_table(BlockDriverState *bs, int min_size)
427 {
428 BDRVQcowState *s = bs->opaque;
429 int new_l1_size, new_l1_size2, ret, i;
430 uint64_t *new_l1_table;
431 uint64_t new_l1_table_offset;
432 uint64_t data64;
433 uint32_t data32;
434
435 new_l1_size = s->l1_size;
436 if (min_size <= new_l1_size)
437 return 0;
438 while (min_size > new_l1_size) {
439 new_l1_size = (new_l1_size * 3 + 1) / 2;
440 }
441 #ifdef DEBUG_ALLOC2
442 printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
443 #endif
444
445 new_l1_size2 = sizeof(uint64_t) * new_l1_size;
446 new_l1_table = qemu_mallocz(new_l1_size2);
447 if (!new_l1_table)
448 return -ENOMEM;
449 memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
450
451 /* write new table (align to cluster) */
452 new_l1_table_offset = alloc_clusters(bs, new_l1_size2);
453
454 for(i = 0; i < s->l1_size; i++)
455 new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
456 ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
457 if (ret != new_l1_size2)
458 goto fail;
459 for(i = 0; i < s->l1_size; i++)
460 new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
461
462 /* set new table */
463 data64 = cpu_to_be64(new_l1_table_offset);
464 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_table_offset),
465 &data64, sizeof(data64)) != sizeof(data64))
466 goto fail;
467 data32 = cpu_to_be32(new_l1_size);
468 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size),
469 &data32, sizeof(data32)) != sizeof(data32))
470 goto fail;
471 qemu_free(s->l1_table);
472 free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
473 s->l1_table_offset = new_l1_table_offset;
474 s->l1_table = new_l1_table;
475 s->l1_size = new_l1_size;
476 return 0;
477 fail:
478 qemu_free(s->l1_table);
479 return -EIO;
480 }
481
482 /*
483 * seek_l2_table
484 *
485 * seek l2_offset in the l2_cache table
486 * if not found, return NULL,
487 * if found,
488 * increments the l2 cache hit count of the entry,
489 * if counter overflow, divide by two all counters
490 * return the pointer to the l2 cache entry
491 *
492 */
493
seek_l2_table(BDRVQcowState * s,uint64_t l2_offset)494 static uint64_t *seek_l2_table(BDRVQcowState *s, uint64_t l2_offset)
495 {
496 int i, j;
497
498 for(i = 0; i < L2_CACHE_SIZE; i++) {
499 if (l2_offset == s->l2_cache_offsets[i]) {
500 /* increment the hit count */
501 if (++s->l2_cache_counts[i] == 0xffffffff) {
502 for(j = 0; j < L2_CACHE_SIZE; j++) {
503 s->l2_cache_counts[j] >>= 1;
504 }
505 }
506 return s->l2_cache + (i << s->l2_bits);
507 }
508 }
509 return NULL;
510 }
511
512 /*
513 * l2_load
514 *
515 * Loads a L2 table into memory. If the table is in the cache, the cache
516 * is used; otherwise the L2 table is loaded from the image file.
517 *
518 * Returns a pointer to the L2 table on success, or NULL if the read from
519 * the image file failed.
520 */
521
l2_load(BlockDriverState * bs,uint64_t l2_offset)522 static uint64_t *l2_load(BlockDriverState *bs, uint64_t l2_offset)
523 {
524 BDRVQcowState *s = bs->opaque;
525 int min_index;
526 uint64_t *l2_table;
527
528 /* seek if the table for the given offset is in the cache */
529
530 l2_table = seek_l2_table(s, l2_offset);
531 if (l2_table != NULL)
532 return l2_table;
533
534 /* not found: load a new entry in the least used one */
535
536 min_index = l2_cache_new_entry(bs);
537 l2_table = s->l2_cache + (min_index << s->l2_bits);
538 if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
539 s->l2_size * sizeof(uint64_t))
540 return NULL;
541 s->l2_cache_offsets[min_index] = l2_offset;
542 s->l2_cache_counts[min_index] = 1;
543
544 return l2_table;
545 }
546
547 /*
548 * l2_allocate
549 *
550 * Allocate a new l2 entry in the file. If l1_index points to an already
551 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
552 * table) copy the contents of the old L2 table into the newly allocated one.
553 * Otherwise the new table is initialized with zeros.
554 *
555 */
556
l2_allocate(BlockDriverState * bs,int l1_index)557 static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
558 {
559 BDRVQcowState *s = bs->opaque;
560 int min_index;
561 uint64_t old_l2_offset, tmp;
562 uint64_t *l2_table, l2_offset;
563
564 old_l2_offset = s->l1_table[l1_index];
565
566 /* allocate a new l2 entry */
567
568 l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
569
570 /* update the L1 entry */
571
572 s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
573
574 tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED);
575 if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
576 &tmp, sizeof(tmp)) != sizeof(tmp))
577 return NULL;
578
579 /* allocate a new entry in the l2 cache */
580
581 min_index = l2_cache_new_entry(bs);
582 l2_table = s->l2_cache + (min_index << s->l2_bits);
583
584 if (old_l2_offset == 0) {
585 /* if there was no old l2 table, clear the new table */
586 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
587 } else {
588 /* if there was an old l2 table, read it from the disk */
589 if (bdrv_pread(s->hd, old_l2_offset,
590 l2_table, s->l2_size * sizeof(uint64_t)) !=
591 s->l2_size * sizeof(uint64_t))
592 return NULL;
593 }
594 /* write the l2 table to the file */
595 if (bdrv_pwrite(s->hd, l2_offset,
596 l2_table, s->l2_size * sizeof(uint64_t)) !=
597 s->l2_size * sizeof(uint64_t))
598 return NULL;
599
600 /* update the l2 cache entry */
601
602 s->l2_cache_offsets[min_index] = l2_offset;
603 s->l2_cache_counts[min_index] = 1;
604
605 return l2_table;
606 }
607
608 /*
609 * get_cluster_offset
610 *
611 * For a given offset of the disk image, return cluster offset in
612 * qcow2 file.
613 *
614 * on entry, *num is the number of contiguous clusters we'd like to
615 * access following offset.
616 *
617 * on exit, *num is the number of contiguous clusters we can read.
618 *
619 * Return 1, if the offset is found
620 * Return 0, otherwise.
621 *
622 */
623
get_cluster_offset(BlockDriverState * bs,uint64_t offset,int * num)624 static uint64_t get_cluster_offset(BlockDriverState *bs,
625 uint64_t offset, int *num)
626 {
627 BDRVQcowState *s = bs->opaque;
628 int l1_index, l2_index;
629 uint64_t l2_offset, *l2_table, cluster_offset, next;
630 int l1_bits;
631 int index_in_cluster, nb_available, nb_needed;
632
633 index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
634 nb_needed = *num + index_in_cluster;
635
636 l1_bits = s->l2_bits + s->cluster_bits;
637
638 /* compute how many bytes there are between the offset and
639 * and the end of the l1 entry
640 */
641
642 nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1));
643
644 /* compute the number of available sectors */
645
646 nb_available = (nb_available >> 9) + index_in_cluster;
647
648 cluster_offset = 0;
649
650 /* seek the the l2 offset in the l1 table */
651
652 l1_index = offset >> l1_bits;
653 if (l1_index >= s->l1_size)
654 goto out;
655
656 l2_offset = s->l1_table[l1_index];
657
658 /* seek the l2 table of the given l2 offset */
659
660 if (!l2_offset)
661 goto out;
662
663 /* load the l2 table in memory */
664
665 l2_offset &= ~QCOW_OFLAG_COPIED;
666 l2_table = l2_load(bs, l2_offset);
667 if (l2_table == NULL)
668 return 0;
669
670 /* find the cluster offset for the given disk offset */
671
672 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
673 cluster_offset = be64_to_cpu(l2_table[l2_index]);
674 nb_available = s->cluster_sectors;
675 l2_index++;
676
677 if (!cluster_offset) {
678
679 /* how many empty clusters ? */
680
681 while (nb_available < nb_needed && !l2_table[l2_index]) {
682 l2_index++;
683 nb_available += s->cluster_sectors;
684 }
685 } else {
686
687 /* how many allocated clusters ? */
688
689 cluster_offset &= ~QCOW_OFLAG_COPIED;
690 while (nb_available < nb_needed) {
691 next = be64_to_cpu(l2_table[l2_index]) & ~QCOW_OFLAG_COPIED;
692 if (next != cluster_offset + (nb_available << 9))
693 break;
694 l2_index++;
695 nb_available += s->cluster_sectors;
696 }
697 }
698
699 out:
700 if (nb_available > nb_needed)
701 nb_available = nb_needed;
702
703 *num = nb_available - index_in_cluster;
704
705 return cluster_offset;
706 }
707
708 /*
709 * free_any_clusters
710 *
711 * free clusters according to its type: compressed or not
712 *
713 */
714
free_any_clusters(BlockDriverState * bs,uint64_t cluster_offset,int nb_clusters)715 static void free_any_clusters(BlockDriverState *bs,
716 uint64_t cluster_offset, int nb_clusters)
717 {
718 BDRVQcowState *s = bs->opaque;
719
720 /* free the cluster */
721
722 if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
723 int nb_csectors;
724 nb_csectors = ((cluster_offset >> s->csize_shift) &
725 s->csize_mask) + 1;
726 free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
727 nb_csectors * 512);
728 return;
729 }
730
731 free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
732
733 return;
734 }
735
736 /*
737 * get_cluster_table
738 *
739 * for a given disk offset, load (and allocate if needed)
740 * the l2 table.
741 *
742 * the l2 table offset in the qcow2 file and the cluster index
743 * in the l2 table are given to the caller.
744 *
745 */
746
get_cluster_table(BlockDriverState * bs,uint64_t offset,uint64_t ** new_l2_table,uint64_t * new_l2_offset,int * new_l2_index)747 static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
748 uint64_t **new_l2_table,
749 uint64_t *new_l2_offset,
750 int *new_l2_index)
751 {
752 BDRVQcowState *s = bs->opaque;
753 int l1_index, l2_index, ret;
754 uint64_t l2_offset, *l2_table;
755
756 /* seek the the l2 offset in the l1 table */
757
758 l1_index = offset >> (s->l2_bits + s->cluster_bits);
759 if (l1_index >= s->l1_size) {
760 ret = grow_l1_table(bs, l1_index + 1);
761 if (ret < 0)
762 return 0;
763 }
764 l2_offset = s->l1_table[l1_index];
765
766 /* seek the l2 table of the given l2 offset */
767
768 if (l2_offset & QCOW_OFLAG_COPIED) {
769 /* load the l2 table in memory */
770 l2_offset &= ~QCOW_OFLAG_COPIED;
771 l2_table = l2_load(bs, l2_offset);
772 if (l2_table == NULL)
773 return 0;
774 } else {
775 if (l2_offset)
776 free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
777 l2_table = l2_allocate(bs, l1_index);
778 if (l2_table == NULL)
779 return 0;
780 l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
781 }
782
783 /* find the cluster offset for the given disk offset */
784
785 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
786
787 *new_l2_table = l2_table;
788 *new_l2_offset = l2_offset;
789 *new_l2_index = l2_index;
790
791 return 1;
792 }
793
794 /*
795 * alloc_compressed_cluster_offset
796 *
797 * For a given offset of the disk image, return cluster offset in
798 * qcow2 file.
799 *
800 * If the offset is not found, allocate a new compressed cluster.
801 *
802 * Return the cluster offset if successful,
803 * Return 0, otherwise.
804 *
805 */
806
alloc_compressed_cluster_offset(BlockDriverState * bs,uint64_t offset,int compressed_size)807 static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
808 uint64_t offset,
809 int compressed_size)
810 {
811 BDRVQcowState *s = bs->opaque;
812 int l2_index, ret;
813 uint64_t l2_offset, *l2_table, cluster_offset;
814 int nb_csectors;
815
816 ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
817 if (ret == 0)
818 return 0;
819
820 cluster_offset = be64_to_cpu(l2_table[l2_index]);
821 if (cluster_offset & QCOW_OFLAG_COPIED)
822 return cluster_offset & ~QCOW_OFLAG_COPIED;
823
824 if (cluster_offset)
825 free_any_clusters(bs, cluster_offset, 1);
826
827 cluster_offset = alloc_bytes(bs, compressed_size);
828 nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
829 (cluster_offset >> 9);
830
831 cluster_offset |= QCOW_OFLAG_COMPRESSED |
832 ((uint64_t)nb_csectors << s->csize_shift);
833
834 /* update L2 table */
835
836 /* compressed clusters never have the copied flag */
837
838 l2_table[l2_index] = cpu_to_be64(cluster_offset);
839 if (bdrv_pwrite(s->hd,
840 l2_offset + l2_index * sizeof(uint64_t),
841 l2_table + l2_index,
842 sizeof(uint64_t)) != sizeof(uint64_t))
843 return 0;
844
845 return cluster_offset;
846 }
847
848 /*
849 * alloc_cluster_offset
850 *
851 * For a given offset of the disk image, return cluster offset in
852 * qcow2 file.
853 *
854 * If the offset is not found, allocate a new cluster.
855 *
856 * Return the cluster offset if successful,
857 * Return 0, otherwise.
858 *
859 */
860
alloc_cluster_offset(BlockDriverState * bs,uint64_t offset,int n_start,int n_end,int * num)861 static uint64_t alloc_cluster_offset(BlockDriverState *bs,
862 uint64_t offset,
863 int n_start, int n_end,
864 int *num)
865 {
866 BDRVQcowState *s = bs->opaque;
867 int l2_index, ret;
868 uint64_t l2_offset, *l2_table, cluster_offset;
869 int nb_available, nb_clusters, i, j;
870 uint64_t start_sect, current;
871
872 ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
873 if (ret == 0)
874 return 0;
875
876 nb_clusters = ((n_end << 9) + s->cluster_size - 1) >>
877 s->cluster_bits;
878 if (nb_clusters > s->l2_size - l2_index)
879 nb_clusters = s->l2_size - l2_index;
880
881 cluster_offset = be64_to_cpu(l2_table[l2_index]);
882
883 /* We keep all QCOW_OFLAG_COPIED clusters */
884
885 if (cluster_offset & QCOW_OFLAG_COPIED) {
886
887 for (i = 1; i < nb_clusters; i++) {
888 current = be64_to_cpu(l2_table[l2_index + i]);
889 if (cluster_offset + (i << s->cluster_bits) != current)
890 break;
891 }
892 nb_clusters = i;
893
894 nb_available = nb_clusters << (s->cluster_bits - 9);
895 if (nb_available > n_end)
896 nb_available = n_end;
897
898 cluster_offset &= ~QCOW_OFLAG_COPIED;
899
900 goto out;
901 }
902
903 /* for the moment, multiple compressed clusters are not managed */
904
905 if (cluster_offset & QCOW_OFLAG_COMPRESSED)
906 nb_clusters = 1;
907
908 /* how many available clusters ? */
909
910 i = 0;
911 while (i < nb_clusters) {
912
913 i++;
914
915 if (!cluster_offset) {
916
917 /* how many free clusters ? */
918
919 while (i < nb_clusters) {
920 cluster_offset = l2_table[l2_index + i];
921 if (cluster_offset != 0)
922 break;
923 i++;
924 }
925
926 if ((cluster_offset & QCOW_OFLAG_COPIED) ||
927 (cluster_offset & QCOW_OFLAG_COMPRESSED))
928 break;
929
930 } else {
931
932 /* how many contiguous clusters ? */
933
934 j = 1;
935 current = 0;
936 while (i < nb_clusters) {
937 current = be64_to_cpu(l2_table[l2_index + i]);
938 if (cluster_offset + (j << s->cluster_bits) != current)
939 break;
940
941 i++;
942 j++;
943 }
944
945 free_any_clusters(bs, cluster_offset, j);
946 if (current)
947 break;
948 cluster_offset = current;
949 }
950 }
951 nb_clusters = i;
952
953 /* allocate a new cluster */
954
955 cluster_offset = alloc_clusters(bs, nb_clusters * s->cluster_size);
956
957 /* we must initialize the cluster content which won't be
958 written */
959
960 nb_available = nb_clusters << (s->cluster_bits - 9);
961 if (nb_available > n_end)
962 nb_available = n_end;
963
964 /* copy content of unmodified sectors */
965
966 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
967 if (n_start) {
968 ret = copy_sectors(bs, start_sect, cluster_offset, 0, n_start);
969 if (ret < 0)
970 return 0;
971 }
972
973 if (nb_available & (s->cluster_sectors - 1)) {
974 uint64_t end = nb_available & ~(uint64_t)(s->cluster_sectors - 1);
975 ret = copy_sectors(bs, start_sect + end,
976 cluster_offset + (end << 9),
977 nb_available - end,
978 s->cluster_sectors);
979 if (ret < 0)
980 return 0;
981 }
982
983 /* update L2 table */
984
985 for (i = 0; i < nb_clusters; i++)
986 l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
987 (i << s->cluster_bits)) |
988 QCOW_OFLAG_COPIED);
989
990 if (bdrv_pwrite(s->hd,
991 l2_offset + l2_index * sizeof(uint64_t),
992 l2_table + l2_index,
993 nb_clusters * sizeof(uint64_t)) !=
994 nb_clusters * sizeof(uint64_t))
995 return 0;
996
997 out:
998 *num = nb_available - n_start;
999
1000 return cluster_offset;
1001 }
1002
qcow_is_allocated(BlockDriverState * bs,int64_t sector_num,int nb_sectors,int * pnum)1003 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
1004 int nb_sectors, int *pnum)
1005 {
1006 uint64_t cluster_offset;
1007
1008 *pnum = nb_sectors;
1009 cluster_offset = get_cluster_offset(bs, sector_num << 9, pnum);
1010
1011 return (cluster_offset != 0);
1012 }
1013
decompress_buffer(uint8_t * out_buf,int out_buf_size,const uint8_t * buf,int buf_size)1014 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
1015 const uint8_t *buf, int buf_size)
1016 {
1017 z_stream strm1, *strm = &strm1;
1018 int ret, out_len;
1019
1020 memset(strm, 0, sizeof(*strm));
1021
1022 strm->next_in = (uint8_t *)buf;
1023 strm->avail_in = buf_size;
1024 strm->next_out = out_buf;
1025 strm->avail_out = out_buf_size;
1026
1027 ret = inflateInit2(strm, -12);
1028 if (ret != Z_OK)
1029 return -1;
1030 ret = inflate(strm, Z_FINISH);
1031 out_len = strm->next_out - out_buf;
1032 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
1033 out_len != out_buf_size) {
1034 inflateEnd(strm);
1035 return -1;
1036 }
1037 inflateEnd(strm);
1038 return 0;
1039 }
1040
decompress_cluster(BDRVQcowState * s,uint64_t cluster_offset)1041 static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
1042 {
1043 int ret, csize, nb_csectors, sector_offset;
1044 uint64_t coffset;
1045
1046 coffset = cluster_offset & s->cluster_offset_mask;
1047 if (s->cluster_cache_offset != coffset) {
1048 nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
1049 sector_offset = coffset & 511;
1050 csize = nb_csectors * 512 - sector_offset;
1051 ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors);
1052 if (ret < 0) {
1053 return -1;
1054 }
1055 if (decompress_buffer(s->cluster_cache, s->cluster_size,
1056 s->cluster_data + sector_offset, csize) < 0) {
1057 return -1;
1058 }
1059 s->cluster_cache_offset = coffset;
1060 }
1061 return 0;
1062 }
1063
1064 /* handle reading after the end of the backing file */
backing_read1(BlockDriverState * bs,int64_t sector_num,uint8_t * buf,int nb_sectors)1065 static int backing_read1(BlockDriverState *bs,
1066 int64_t sector_num, uint8_t *buf, int nb_sectors)
1067 {
1068 int n1;
1069 if ((sector_num + nb_sectors) <= bs->total_sectors)
1070 return nb_sectors;
1071 if (sector_num >= bs->total_sectors)
1072 n1 = 0;
1073 else
1074 n1 = bs->total_sectors - sector_num;
1075 memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1));
1076 return n1;
1077 }
1078
qcow_read(BlockDriverState * bs,int64_t sector_num,uint8_t * buf,int nb_sectors)1079 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
1080 uint8_t *buf, int nb_sectors)
1081 {
1082 BDRVQcowState *s = bs->opaque;
1083 int ret, index_in_cluster, n, n1;
1084 uint64_t cluster_offset;
1085
1086 while (nb_sectors > 0) {
1087 n = nb_sectors;
1088 cluster_offset = get_cluster_offset(bs, sector_num << 9, &n);
1089 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1090 if (!cluster_offset) {
1091 if (bs->backing_hd) {
1092 /* read from the base image */
1093 n1 = backing_read1(bs->backing_hd, sector_num, buf, n);
1094 if (n1 > 0) {
1095 ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
1096 if (ret < 0)
1097 return -1;
1098 }
1099 } else {
1100 memset(buf, 0, 512 * n);
1101 }
1102 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
1103 if (decompress_cluster(s, cluster_offset) < 0)
1104 return -1;
1105 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
1106 } else {
1107 ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
1108 if (ret != n * 512)
1109 return -1;
1110 if (s->crypt_method) {
1111 encrypt_sectors(s, sector_num, buf, buf, n, 0,
1112 &s->aes_decrypt_key);
1113 }
1114 }
1115 nb_sectors -= n;
1116 sector_num += n;
1117 buf += n * 512;
1118 }
1119 return 0;
1120 }
1121
qcow_write(BlockDriverState * bs,int64_t sector_num,const uint8_t * buf,int nb_sectors)1122 static int qcow_write(BlockDriverState *bs, int64_t sector_num,
1123 const uint8_t *buf, int nb_sectors)
1124 {
1125 BDRVQcowState *s = bs->opaque;
1126 int ret, index_in_cluster, n;
1127 uint64_t cluster_offset;
1128 int n_end;
1129
1130 while (nb_sectors > 0) {
1131 index_in_cluster = sector_num & (s->cluster_sectors - 1);
1132 n_end = index_in_cluster + nb_sectors;
1133 if (s->crypt_method &&
1134 n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
1135 n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
1136 cluster_offset = alloc_cluster_offset(bs, sector_num << 9,
1137 index_in_cluster,
1138 n_end, &n);
1139 if (!cluster_offset)
1140 return -1;
1141 if (s->crypt_method) {
1142 encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
1143 &s->aes_encrypt_key);
1144 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
1145 s->cluster_data, n * 512);
1146 } else {
1147 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
1148 }
1149 if (ret != n * 512)
1150 return -1;
1151 nb_sectors -= n;
1152 sector_num += n;
1153 buf += n * 512;
1154 }
1155 s->cluster_cache_offset = -1; /* disable compressed cache */
1156 return 0;
1157 }
1158
1159 typedef struct QCowAIOCB {
1160 BlockDriverAIOCB common;
1161 int64_t sector_num;
1162 uint8_t *buf;
1163 int nb_sectors;
1164 int n;
1165 uint64_t cluster_offset;
1166 uint8_t *cluster_data;
1167 BlockDriverAIOCB *hd_aiocb;
1168 } QCowAIOCB;
1169
qcow_aio_read_cb(void * opaque,int ret)1170 static void qcow_aio_read_cb(void *opaque, int ret)
1171 {
1172 QCowAIOCB *acb = opaque;
1173 BlockDriverState *bs = acb->common.bs;
1174 BDRVQcowState *s = bs->opaque;
1175 int index_in_cluster, n1;
1176
1177 acb->hd_aiocb = NULL;
1178 if (ret < 0) {
1179 fail:
1180 acb->common.cb(acb->common.opaque, ret);
1181 qemu_aio_release(acb);
1182 return;
1183 }
1184
1185 redo:
1186 /* post process the read buffer */
1187 if (!acb->cluster_offset) {
1188 /* nothing to do */
1189 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
1190 /* nothing to do */
1191 } else {
1192 if (s->crypt_method) {
1193 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
1194 acb->n, 0,
1195 &s->aes_decrypt_key);
1196 }
1197 }
1198
1199 acb->nb_sectors -= acb->n;
1200 acb->sector_num += acb->n;
1201 acb->buf += acb->n * 512;
1202
1203 if (acb->nb_sectors == 0) {
1204 /* request completed */
1205 acb->common.cb(acb->common.opaque, 0);
1206 qemu_aio_release(acb);
1207 return;
1208 }
1209
1210 /* prepare next AIO request */
1211 acb->n = acb->nb_sectors;
1212 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
1213 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
1214
1215 if (!acb->cluster_offset) {
1216 if (bs->backing_hd) {
1217 /* read from the base image */
1218 n1 = backing_read1(bs->backing_hd, acb->sector_num,
1219 acb->buf, acb->n);
1220 if (n1 > 0) {
1221 acb->hd_aiocb = bdrv_aio_read(bs->backing_hd, acb->sector_num,
1222 acb->buf, acb->n, qcow_aio_read_cb, acb);
1223 if (acb->hd_aiocb == NULL)
1224 goto fail;
1225 } else {
1226 goto redo;
1227 }
1228 } else {
1229 /* Note: in this case, no need to wait */
1230 memset(acb->buf, 0, 512 * acb->n);
1231 goto redo;
1232 }
1233 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
1234 /* add AIO support for compressed blocks ? */
1235 if (decompress_cluster(s, acb->cluster_offset) < 0)
1236 goto fail;
1237 memcpy(acb->buf,
1238 s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
1239 goto redo;
1240 } else {
1241 if ((acb->cluster_offset & 511) != 0) {
1242 ret = -EIO;
1243 goto fail;
1244 }
1245 acb->hd_aiocb = bdrv_aio_read(s->hd,
1246 (acb->cluster_offset >> 9) + index_in_cluster,
1247 acb->buf, acb->n, qcow_aio_read_cb, acb);
1248 if (acb->hd_aiocb == NULL)
1249 goto fail;
1250 }
1251 }
1252
qcow_aio_setup(BlockDriverState * bs,int64_t sector_num,uint8_t * buf,int nb_sectors,BlockDriverCompletionFunc * cb,void * opaque)1253 static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
1254 int64_t sector_num, uint8_t *buf, int nb_sectors,
1255 BlockDriverCompletionFunc *cb, void *opaque)
1256 {
1257 QCowAIOCB *acb;
1258
1259 acb = qemu_aio_get(bs, cb, opaque);
1260 if (!acb)
1261 return NULL;
1262 acb->hd_aiocb = NULL;
1263 acb->sector_num = sector_num;
1264 acb->buf = buf;
1265 acb->nb_sectors = nb_sectors;
1266 acb->n = 0;
1267 acb->cluster_offset = 0;
1268 return acb;
1269 }
1270
qcow_aio_read(BlockDriverState * bs,int64_t sector_num,uint8_t * buf,int nb_sectors,BlockDriverCompletionFunc * cb,void * opaque)1271 static BlockDriverAIOCB *qcow_aio_read(BlockDriverState *bs,
1272 int64_t sector_num, uint8_t *buf, int nb_sectors,
1273 BlockDriverCompletionFunc *cb, void *opaque)
1274 {
1275 QCowAIOCB *acb;
1276
1277 acb = qcow_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque);
1278 if (!acb)
1279 return NULL;
1280
1281 qcow_aio_read_cb(acb, 0);
1282 return &acb->common;
1283 }
1284
qcow_aio_write_cb(void * opaque,int ret)1285 static void qcow_aio_write_cb(void *opaque, int ret)
1286 {
1287 QCowAIOCB *acb = opaque;
1288 BlockDriverState *bs = acb->common.bs;
1289 BDRVQcowState *s = bs->opaque;
1290 int index_in_cluster;
1291 uint64_t cluster_offset;
1292 const uint8_t *src_buf;
1293 int n_end;
1294
1295 acb->hd_aiocb = NULL;
1296
1297 if (ret < 0) {
1298 fail:
1299 acb->common.cb(acb->common.opaque, ret);
1300 qemu_aio_release(acb);
1301 return;
1302 }
1303
1304 acb->nb_sectors -= acb->n;
1305 acb->sector_num += acb->n;
1306 acb->buf += acb->n * 512;
1307
1308 if (acb->nb_sectors == 0) {
1309 /* request completed */
1310 acb->common.cb(acb->common.opaque, 0);
1311 qemu_aio_release(acb);
1312 return;
1313 }
1314
1315 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
1316 n_end = index_in_cluster + acb->nb_sectors;
1317 if (s->crypt_method &&
1318 n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
1319 n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
1320
1321 cluster_offset = alloc_cluster_offset(bs, acb->sector_num << 9,
1322 index_in_cluster,
1323 n_end, &acb->n);
1324 if (!cluster_offset || (cluster_offset & 511) != 0) {
1325 ret = -EIO;
1326 goto fail;
1327 }
1328 if (s->crypt_method) {
1329 if (!acb->cluster_data) {
1330 acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
1331 s->cluster_size);
1332 if (!acb->cluster_data) {
1333 ret = -ENOMEM;
1334 goto fail;
1335 }
1336 }
1337 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
1338 acb->n, 1, &s->aes_encrypt_key);
1339 src_buf = acb->cluster_data;
1340 } else {
1341 src_buf = acb->buf;
1342 }
1343 acb->hd_aiocb = bdrv_aio_write(s->hd,
1344 (cluster_offset >> 9) + index_in_cluster,
1345 src_buf, acb->n,
1346 qcow_aio_write_cb, acb);
1347 if (acb->hd_aiocb == NULL)
1348 goto fail;
1349 }
1350
qcow_aio_write(BlockDriverState * bs,int64_t sector_num,const uint8_t * buf,int nb_sectors,BlockDriverCompletionFunc * cb,void * opaque)1351 static BlockDriverAIOCB *qcow_aio_write(BlockDriverState *bs,
1352 int64_t sector_num, const uint8_t *buf, int nb_sectors,
1353 BlockDriverCompletionFunc *cb, void *opaque)
1354 {
1355 BDRVQcowState *s = bs->opaque;
1356 QCowAIOCB *acb;
1357
1358 s->cluster_cache_offset = -1; /* disable compressed cache */
1359
1360 acb = qcow_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque);
1361 if (!acb)
1362 return NULL;
1363
1364 qcow_aio_write_cb(acb, 0);
1365 return &acb->common;
1366 }
1367
qcow_aio_cancel(BlockDriverAIOCB * blockacb)1368 static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
1369 {
1370 QCowAIOCB *acb = (QCowAIOCB *)blockacb;
1371 if (acb->hd_aiocb)
1372 bdrv_aio_cancel(acb->hd_aiocb);
1373 qemu_aio_release(acb);
1374 }
1375
qcow_close(BlockDriverState * bs)1376 static void qcow_close(BlockDriverState *bs)
1377 {
1378 BDRVQcowState *s = bs->opaque;
1379 qemu_free(s->l1_table);
1380 qemu_free(s->l2_cache);
1381 qemu_free(s->cluster_cache);
1382 qemu_free(s->cluster_data);
1383 refcount_close(bs);
1384 bdrv_delete(s->hd);
1385 }
1386
1387 /* XXX: use std qcow open function ? */
1388 typedef struct QCowCreateState {
1389 int cluster_size;
1390 int cluster_bits;
1391 uint16_t *refcount_block;
1392 uint64_t *refcount_table;
1393 int64_t l1_table_offset;
1394 int64_t refcount_table_offset;
1395 int64_t refcount_block_offset;
1396 } QCowCreateState;
1397
create_refcount_update(QCowCreateState * s,int64_t offset,int64_t size)1398 static void create_refcount_update(QCowCreateState *s,
1399 int64_t offset, int64_t size)
1400 {
1401 int refcount;
1402 int64_t start, last, cluster_offset;
1403 uint16_t *p;
1404
1405 start = offset & ~(s->cluster_size - 1);
1406 last = (offset + size - 1) & ~(s->cluster_size - 1);
1407 for(cluster_offset = start; cluster_offset <= last;
1408 cluster_offset += s->cluster_size) {
1409 p = &s->refcount_block[cluster_offset >> s->cluster_bits];
1410 refcount = be16_to_cpu(*p);
1411 refcount++;
1412 *p = cpu_to_be16(refcount);
1413 }
1414 }
1415
qcow_create(const char * filename,int64_t total_size,const char * backing_file,int flags)1416 static int qcow_create(const char *filename, int64_t total_size,
1417 const char *backing_file, int flags)
1418 {
1419 int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
1420 QCowHeader header;
1421 uint64_t tmp, offset;
1422 QCowCreateState s1, *s = &s1;
1423
1424 memset(s, 0, sizeof(*s));
1425
1426 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
1427 if (fd < 0)
1428 return -1;
1429 memset(&header, 0, sizeof(header));
1430 header.magic = cpu_to_be32(QCOW_MAGIC);
1431 header.version = cpu_to_be32(QCOW_VERSION);
1432 header.size = cpu_to_be64(total_size * 512);
1433 header_size = sizeof(header);
1434 backing_filename_len = 0;
1435 if (backing_file) {
1436 header.backing_file_offset = cpu_to_be64(header_size);
1437 backing_filename_len = strlen(backing_file);
1438 header.backing_file_size = cpu_to_be32(backing_filename_len);
1439 header_size += backing_filename_len;
1440 }
1441 s->cluster_bits = 12; /* 4 KB clusters */
1442 s->cluster_size = 1 << s->cluster_bits;
1443 header.cluster_bits = cpu_to_be32(s->cluster_bits);
1444 header_size = (header_size + 7) & ~7;
1445 if (flags & BLOCK_FLAG_ENCRYPT) {
1446 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
1447 } else {
1448 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
1449 }
1450 l2_bits = s->cluster_bits - 3;
1451 shift = s->cluster_bits + l2_bits;
1452 l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
1453 offset = align_offset(header_size, s->cluster_size);
1454 s->l1_table_offset = offset;
1455 header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
1456 header.l1_size = cpu_to_be32(l1_size);
1457 offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
1458
1459 s->refcount_table = qemu_mallocz(s->cluster_size);
1460 if (!s->refcount_table)
1461 goto fail;
1462 s->refcount_block = qemu_mallocz(s->cluster_size);
1463 if (!s->refcount_block)
1464 goto fail;
1465
1466 s->refcount_table_offset = offset;
1467 header.refcount_table_offset = cpu_to_be64(offset);
1468 header.refcount_table_clusters = cpu_to_be32(1);
1469 offset += s->cluster_size;
1470
1471 s->refcount_table[0] = cpu_to_be64(offset);
1472 s->refcount_block_offset = offset;
1473 offset += s->cluster_size;
1474
1475 /* update refcounts */
1476 create_refcount_update(s, 0, header_size);
1477 create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t));
1478 create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
1479 create_refcount_update(s, s->refcount_block_offset, s->cluster_size);
1480
1481 /* write all the data */
1482 write(fd, &header, sizeof(header));
1483 if (backing_file) {
1484 write(fd, backing_file, backing_filename_len);
1485 }
1486 lseek(fd, s->l1_table_offset, SEEK_SET);
1487 tmp = 0;
1488 for(i = 0;i < l1_size; i++) {
1489 write(fd, &tmp, sizeof(tmp));
1490 }
1491 lseek(fd, s->refcount_table_offset, SEEK_SET);
1492 write(fd, s->refcount_table, s->cluster_size);
1493
1494 lseek(fd, s->refcount_block_offset, SEEK_SET);
1495 write(fd, s->refcount_block, s->cluster_size);
1496
1497 qemu_free(s->refcount_table);
1498 qemu_free(s->refcount_block);
1499 close(fd);
1500 return 0;
1501 fail:
1502 qemu_free(s->refcount_table);
1503 qemu_free(s->refcount_block);
1504 close(fd);
1505 return -ENOMEM;
1506 }
1507
qcow_make_empty(BlockDriverState * bs)1508 static int qcow_make_empty(BlockDriverState *bs)
1509 {
1510 #if 0
1511 /* XXX: not correct */
1512 BDRVQcowState *s = bs->opaque;
1513 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1514 int ret;
1515
1516 memset(s->l1_table, 0, l1_length);
1517 if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
1518 return -1;
1519 ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
1520 if (ret < 0)
1521 return ret;
1522
1523 l2_cache_reset(bs);
1524 #endif
1525 return 0;
1526 }
1527
1528 /* XXX: put compressed sectors first, then all the cluster aligned
1529 tables to avoid losing bytes in alignment */
qcow_write_compressed(BlockDriverState * bs,int64_t sector_num,const uint8_t * buf,int nb_sectors)1530 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
1531 const uint8_t *buf, int nb_sectors)
1532 {
1533 BDRVQcowState *s = bs->opaque;
1534 z_stream strm;
1535 int ret, out_len;
1536 uint8_t *out_buf;
1537 uint64_t cluster_offset;
1538
1539 if (nb_sectors == 0) {
1540 /* align end of file to a sector boundary to ease reading with
1541 sector based I/Os */
1542 cluster_offset = bdrv_getlength(s->hd);
1543 cluster_offset = (cluster_offset + 511) & ~511;
1544 bdrv_truncate(s->hd, cluster_offset);
1545 return 0;
1546 }
1547
1548 if (nb_sectors != s->cluster_sectors)
1549 return -EINVAL;
1550
1551 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
1552 if (!out_buf)
1553 return -ENOMEM;
1554
1555 /* best compression, small window, no zlib header */
1556 memset(&strm, 0, sizeof(strm));
1557 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1558 Z_DEFLATED, -12,
1559 9, Z_DEFAULT_STRATEGY);
1560 if (ret != 0) {
1561 qemu_free(out_buf);
1562 return -1;
1563 }
1564
1565 strm.avail_in = s->cluster_size;
1566 strm.next_in = (uint8_t *)buf;
1567 strm.avail_out = s->cluster_size;
1568 strm.next_out = out_buf;
1569
1570 ret = deflate(&strm, Z_FINISH);
1571 if (ret != Z_STREAM_END && ret != Z_OK) {
1572 qemu_free(out_buf);
1573 deflateEnd(&strm);
1574 return -1;
1575 }
1576 out_len = strm.next_out - out_buf;
1577
1578 deflateEnd(&strm);
1579
1580 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1581 /* could not compress: write normal cluster */
1582 qcow_write(bs, sector_num, buf, s->cluster_sectors);
1583 } else {
1584 cluster_offset = alloc_compressed_cluster_offset(bs, sector_num << 9,
1585 out_len);
1586 if (!cluster_offset)
1587 return -1;
1588 cluster_offset &= s->cluster_offset_mask;
1589 if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
1590 qemu_free(out_buf);
1591 return -1;
1592 }
1593 }
1594
1595 qemu_free(out_buf);
1596 return 0;
1597 }
1598
qcow_flush(BlockDriverState * bs)1599 static void qcow_flush(BlockDriverState *bs)
1600 {
1601 BDRVQcowState *s = bs->opaque;
1602 bdrv_flush(s->hd);
1603 }
1604
qcow_get_info(BlockDriverState * bs,BlockDriverInfo * bdi)1605 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1606 {
1607 BDRVQcowState *s = bs->opaque;
1608 bdi->cluster_size = s->cluster_size;
1609 bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
1610 (s->cluster_bits + s->l2_bits);
1611 return 0;
1612 }
1613
1614 /*********************************************************/
1615 /* snapshot support */
1616
1617 /* update the refcounts of snapshots and the copied flag */
update_snapshot_refcount(BlockDriverState * bs,int64_t l1_table_offset,int l1_size,int addend)1618 static int update_snapshot_refcount(BlockDriverState *bs,
1619 int64_t l1_table_offset,
1620 int l1_size,
1621 int addend)
1622 {
1623 BDRVQcowState *s = bs->opaque;
1624 uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
1625 int64_t old_offset, old_l2_offset;
1626 int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
1627
1628 l2_cache_reset(bs);
1629
1630 l2_table = NULL;
1631 l1_table = NULL;
1632 l1_size2 = l1_size * sizeof(uint64_t);
1633 l1_allocated = 0;
1634 if (l1_table_offset != s->l1_table_offset) {
1635 l1_table = qemu_malloc(l1_size2);
1636 if (!l1_table)
1637 goto fail;
1638 l1_allocated = 1;
1639 if (bdrv_pread(s->hd, l1_table_offset,
1640 l1_table, l1_size2) != l1_size2)
1641 goto fail;
1642 for(i = 0;i < l1_size; i++)
1643 be64_to_cpus(&l1_table[i]);
1644 } else {
1645 assert(l1_size == s->l1_size);
1646 l1_table = s->l1_table;
1647 l1_allocated = 0;
1648 }
1649
1650 l2_size = s->l2_size * sizeof(uint64_t);
1651 l2_table = qemu_malloc(l2_size);
1652 if (!l2_table)
1653 goto fail;
1654 l1_modified = 0;
1655 for(i = 0; i < l1_size; i++) {
1656 l2_offset = l1_table[i];
1657 if (l2_offset) {
1658 old_l2_offset = l2_offset;
1659 l2_offset &= ~QCOW_OFLAG_COPIED;
1660 l2_modified = 0;
1661 if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
1662 goto fail;
1663 for(j = 0; j < s->l2_size; j++) {
1664 offset = be64_to_cpu(l2_table[j]);
1665 if (offset != 0) {
1666 old_offset = offset;
1667 offset &= ~QCOW_OFLAG_COPIED;
1668 if (offset & QCOW_OFLAG_COMPRESSED) {
1669 nb_csectors = ((offset >> s->csize_shift) &
1670 s->csize_mask) + 1;
1671 if (addend != 0)
1672 update_refcount(bs, (offset & s->cluster_offset_mask) & ~511,
1673 nb_csectors * 512, addend);
1674 /* compressed clusters are never modified */
1675 refcount = 2;
1676 } else {
1677 if (addend != 0) {
1678 refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend);
1679 } else {
1680 refcount = get_refcount(bs, offset >> s->cluster_bits);
1681 }
1682 }
1683
1684 if (refcount == 1) {
1685 offset |= QCOW_OFLAG_COPIED;
1686 }
1687 if (offset != old_offset) {
1688 l2_table[j] = cpu_to_be64(offset);
1689 l2_modified = 1;
1690 }
1691 }
1692 }
1693 if (l2_modified) {
1694 if (bdrv_pwrite(s->hd,
1695 l2_offset, l2_table, l2_size) != l2_size)
1696 goto fail;
1697 }
1698
1699 if (addend != 0) {
1700 refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend);
1701 } else {
1702 refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
1703 }
1704 if (refcount == 1) {
1705 l2_offset |= QCOW_OFLAG_COPIED;
1706 }
1707 if (l2_offset != old_l2_offset) {
1708 l1_table[i] = l2_offset;
1709 l1_modified = 1;
1710 }
1711 }
1712 }
1713 if (l1_modified) {
1714 for(i = 0; i < l1_size; i++)
1715 cpu_to_be64s(&l1_table[i]);
1716 if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
1717 l1_size2) != l1_size2)
1718 goto fail;
1719 for(i = 0; i < l1_size; i++)
1720 be64_to_cpus(&l1_table[i]);
1721 }
1722 if (l1_allocated)
1723 qemu_free(l1_table);
1724 qemu_free(l2_table);
1725 return 0;
1726 fail:
1727 if (l1_allocated)
1728 qemu_free(l1_table);
1729 qemu_free(l2_table);
1730 return -EIO;
1731 }
1732
qcow_free_snapshots(BlockDriverState * bs)1733 static void qcow_free_snapshots(BlockDriverState *bs)
1734 {
1735 BDRVQcowState *s = bs->opaque;
1736 int i;
1737
1738 for(i = 0; i < s->nb_snapshots; i++) {
1739 qemu_free(s->snapshots[i].name);
1740 qemu_free(s->snapshots[i].id_str);
1741 }
1742 qemu_free(s->snapshots);
1743 s->snapshots = NULL;
1744 s->nb_snapshots = 0;
1745 }
1746
qcow_read_snapshots(BlockDriverState * bs)1747 static int qcow_read_snapshots(BlockDriverState *bs)
1748 {
1749 BDRVQcowState *s = bs->opaque;
1750 QCowSnapshotHeader h;
1751 QCowSnapshot *sn;
1752 int i, id_str_size, name_size;
1753 int64_t offset;
1754 uint32_t extra_data_size;
1755
1756 offset = s->snapshots_offset;
1757 s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
1758 if (!s->snapshots)
1759 goto fail;
1760 for(i = 0; i < s->nb_snapshots; i++) {
1761 offset = align_offset(offset, 8);
1762 if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h))
1763 goto fail;
1764 offset += sizeof(h);
1765 sn = s->snapshots + i;
1766 sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
1767 sn->l1_size = be32_to_cpu(h.l1_size);
1768 sn->vm_state_size = be32_to_cpu(h.vm_state_size);
1769 sn->date_sec = be32_to_cpu(h.date_sec);
1770 sn->date_nsec = be32_to_cpu(h.date_nsec);
1771 sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
1772 extra_data_size = be32_to_cpu(h.extra_data_size);
1773
1774 id_str_size = be16_to_cpu(h.id_str_size);
1775 name_size = be16_to_cpu(h.name_size);
1776
1777 offset += extra_data_size;
1778
1779 sn->id_str = qemu_malloc(id_str_size + 1);
1780 if (!sn->id_str)
1781 goto fail;
1782 if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
1783 goto fail;
1784 offset += id_str_size;
1785 sn->id_str[id_str_size] = '\0';
1786
1787 sn->name = qemu_malloc(name_size + 1);
1788 if (!sn->name)
1789 goto fail;
1790 if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size)
1791 goto fail;
1792 offset += name_size;
1793 sn->name[name_size] = '\0';
1794 }
1795 s->snapshots_size = offset - s->snapshots_offset;
1796 return 0;
1797 fail:
1798 qcow_free_snapshots(bs);
1799 return -1;
1800 }
1801
1802 /* add at the end of the file a new list of snapshots */
qcow_write_snapshots(BlockDriverState * bs)1803 static int qcow_write_snapshots(BlockDriverState *bs)
1804 {
1805 BDRVQcowState *s = bs->opaque;
1806 QCowSnapshot *sn;
1807 QCowSnapshotHeader h;
1808 int i, name_size, id_str_size, snapshots_size;
1809 uint64_t data64;
1810 uint32_t data32;
1811 int64_t offset, snapshots_offset;
1812
1813 /* compute the size of the snapshots */
1814 offset = 0;
1815 for(i = 0; i < s->nb_snapshots; i++) {
1816 sn = s->snapshots + i;
1817 offset = align_offset(offset, 8);
1818 offset += sizeof(h);
1819 offset += strlen(sn->id_str);
1820 offset += strlen(sn->name);
1821 }
1822 snapshots_size = offset;
1823
1824 snapshots_offset = alloc_clusters(bs, snapshots_size);
1825 offset = snapshots_offset;
1826
1827 for(i = 0; i < s->nb_snapshots; i++) {
1828 sn = s->snapshots + i;
1829 memset(&h, 0, sizeof(h));
1830 h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
1831 h.l1_size = cpu_to_be32(sn->l1_size);
1832 h.vm_state_size = cpu_to_be32(sn->vm_state_size);
1833 h.date_sec = cpu_to_be32(sn->date_sec);
1834 h.date_nsec = cpu_to_be32(sn->date_nsec);
1835 h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
1836
1837 id_str_size = strlen(sn->id_str);
1838 name_size = strlen(sn->name);
1839 h.id_str_size = cpu_to_be16(id_str_size);
1840 h.name_size = cpu_to_be16(name_size);
1841 offset = align_offset(offset, 8);
1842 if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h))
1843 goto fail;
1844 offset += sizeof(h);
1845 if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
1846 goto fail;
1847 offset += id_str_size;
1848 if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size)
1849 goto fail;
1850 offset += name_size;
1851 }
1852
1853 /* update the various header fields */
1854 data64 = cpu_to_be64(snapshots_offset);
1855 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset),
1856 &data64, sizeof(data64)) != sizeof(data64))
1857 goto fail;
1858 data32 = cpu_to_be32(s->nb_snapshots);
1859 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots),
1860 &data32, sizeof(data32)) != sizeof(data32))
1861 goto fail;
1862
1863 /* free the old snapshot table */
1864 free_clusters(bs, s->snapshots_offset, s->snapshots_size);
1865 s->snapshots_offset = snapshots_offset;
1866 s->snapshots_size = snapshots_size;
1867 return 0;
1868 fail:
1869 return -1;
1870 }
1871
find_new_snapshot_id(BlockDriverState * bs,char * id_str,int id_str_size)1872 static void find_new_snapshot_id(BlockDriverState *bs,
1873 char *id_str, int id_str_size)
1874 {
1875 BDRVQcowState *s = bs->opaque;
1876 QCowSnapshot *sn;
1877 int i, id, id_max = 0;
1878
1879 for(i = 0; i < s->nb_snapshots; i++) {
1880 sn = s->snapshots + i;
1881 id = strtoul(sn->id_str, NULL, 10);
1882 if (id > id_max)
1883 id_max = id;
1884 }
1885 snprintf(id_str, id_str_size, "%d", id_max + 1);
1886 }
1887
find_snapshot_by_id(BlockDriverState * bs,const char * id_str)1888 static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
1889 {
1890 BDRVQcowState *s = bs->opaque;
1891 int i;
1892
1893 for(i = 0; i < s->nb_snapshots; i++) {
1894 if (!strcmp(s->snapshots[i].id_str, id_str))
1895 return i;
1896 }
1897 return -1;
1898 }
1899
find_snapshot_by_id_or_name(BlockDriverState * bs,const char * name)1900 static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
1901 {
1902 BDRVQcowState *s = bs->opaque;
1903 int i, ret;
1904
1905 ret = find_snapshot_by_id(bs, name);
1906 if (ret >= 0)
1907 return ret;
1908 for(i = 0; i < s->nb_snapshots; i++) {
1909 if (!strcmp(s->snapshots[i].name, name))
1910 return i;
1911 }
1912 return -1;
1913 }
1914
1915 /* if no id is provided, a new one is constructed */
qcow_snapshot_create(BlockDriverState * bs,QEMUSnapshotInfo * sn_info)1916 static int qcow_snapshot_create(BlockDriverState *bs,
1917 QEMUSnapshotInfo *sn_info)
1918 {
1919 BDRVQcowState *s = bs->opaque;
1920 QCowSnapshot *snapshots1, sn1, *sn = &sn1;
1921 int i, ret;
1922 uint64_t *l1_table = NULL;
1923
1924 memset(sn, 0, sizeof(*sn));
1925
1926 if (sn_info->id_str[0] == '\0') {
1927 /* compute a new id */
1928 find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
1929 }
1930
1931 /* check that the ID is unique */
1932 if (find_snapshot_by_id(bs, sn_info->id_str) >= 0)
1933 return -ENOENT;
1934
1935 sn->id_str = qemu_strdup(sn_info->id_str);
1936 if (!sn->id_str)
1937 goto fail;
1938 sn->name = qemu_strdup(sn_info->name);
1939 if (!sn->name)
1940 goto fail;
1941 sn->vm_state_size = sn_info->vm_state_size;
1942 sn->date_sec = sn_info->date_sec;
1943 sn->date_nsec = sn_info->date_nsec;
1944 sn->vm_clock_nsec = sn_info->vm_clock_nsec;
1945
1946 ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
1947 if (ret < 0)
1948 goto fail;
1949
1950 /* create the L1 table of the snapshot */
1951 sn->l1_table_offset = alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
1952 sn->l1_size = s->l1_size;
1953
1954 l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
1955 if (!l1_table)
1956 goto fail;
1957 for(i = 0; i < s->l1_size; i++) {
1958 l1_table[i] = cpu_to_be64(s->l1_table[i]);
1959 }
1960 if (bdrv_pwrite(s->hd, sn->l1_table_offset,
1961 l1_table, s->l1_size * sizeof(uint64_t)) !=
1962 (s->l1_size * sizeof(uint64_t)))
1963 goto fail;
1964 qemu_free(l1_table);
1965 l1_table = NULL;
1966
1967 snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
1968 if (!snapshots1)
1969 goto fail;
1970 memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
1971 s->snapshots = snapshots1;
1972 s->snapshots[s->nb_snapshots++] = *sn;
1973
1974 if (qcow_write_snapshots(bs) < 0)
1975 goto fail;
1976 #ifdef DEBUG_ALLOC
1977 check_refcounts(bs);
1978 #endif
1979 return 0;
1980 fail:
1981 qemu_free(sn->name);
1982 qemu_free(l1_table);
1983 return -1;
1984 }
1985
1986 /* copy the snapshot 'snapshot_name' into the current disk image */
qcow_snapshot_goto(BlockDriverState * bs,const char * snapshot_id)1987 static int qcow_snapshot_goto(BlockDriverState *bs,
1988 const char *snapshot_id)
1989 {
1990 BDRVQcowState *s = bs->opaque;
1991 QCowSnapshot *sn;
1992 int i, snapshot_index, l1_size2;
1993
1994 snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
1995 if (snapshot_index < 0)
1996 return -ENOENT;
1997 sn = &s->snapshots[snapshot_index];
1998
1999 if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
2000 goto fail;
2001
2002 if (grow_l1_table(bs, sn->l1_size) < 0)
2003 goto fail;
2004
2005 s->l1_size = sn->l1_size;
2006 l1_size2 = s->l1_size * sizeof(uint64_t);
2007 /* copy the snapshot l1 table to the current l1 table */
2008 if (bdrv_pread(s->hd, sn->l1_table_offset,
2009 s->l1_table, l1_size2) != l1_size2)
2010 goto fail;
2011 if (bdrv_pwrite(s->hd, s->l1_table_offset,
2012 s->l1_table, l1_size2) != l1_size2)
2013 goto fail;
2014 for(i = 0;i < s->l1_size; i++) {
2015 be64_to_cpus(&s->l1_table[i]);
2016 }
2017
2018 if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
2019 goto fail;
2020
2021 #ifdef DEBUG_ALLOC
2022 check_refcounts(bs);
2023 #endif
2024 return 0;
2025 fail:
2026 return -EIO;
2027 }
2028
qcow_snapshot_delete(BlockDriverState * bs,const char * snapshot_id)2029 static int qcow_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
2030 {
2031 BDRVQcowState *s = bs->opaque;
2032 QCowSnapshot *sn;
2033 int snapshot_index, ret;
2034
2035 snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
2036 if (snapshot_index < 0)
2037 return -ENOENT;
2038 sn = &s->snapshots[snapshot_index];
2039
2040 ret = update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
2041 if (ret < 0)
2042 return ret;
2043 /* must update the copied flag on the current cluster offsets */
2044 ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
2045 if (ret < 0)
2046 return ret;
2047 free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
2048
2049 qemu_free(sn->id_str);
2050 qemu_free(sn->name);
2051 memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
2052 s->nb_snapshots--;
2053 ret = qcow_write_snapshots(bs);
2054 if (ret < 0) {
2055 /* XXX: restore snapshot if error ? */
2056 return ret;
2057 }
2058 #ifdef DEBUG_ALLOC
2059 check_refcounts(bs);
2060 #endif
2061 return 0;
2062 }
2063
qcow_snapshot_list(BlockDriverState * bs,QEMUSnapshotInfo ** psn_tab)2064 static int qcow_snapshot_list(BlockDriverState *bs,
2065 QEMUSnapshotInfo **psn_tab)
2066 {
2067 BDRVQcowState *s = bs->opaque;
2068 QEMUSnapshotInfo *sn_tab, *sn_info;
2069 QCowSnapshot *sn;
2070 int i;
2071
2072 sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
2073 if (!sn_tab)
2074 goto fail;
2075 for(i = 0; i < s->nb_snapshots; i++) {
2076 sn_info = sn_tab + i;
2077 sn = s->snapshots + i;
2078 pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
2079 sn->id_str);
2080 pstrcpy(sn_info->name, sizeof(sn_info->name),
2081 sn->name);
2082 sn_info->vm_state_size = sn->vm_state_size;
2083 sn_info->date_sec = sn->date_sec;
2084 sn_info->date_nsec = sn->date_nsec;
2085 sn_info->vm_clock_nsec = sn->vm_clock_nsec;
2086 }
2087 *psn_tab = sn_tab;
2088 return s->nb_snapshots;
2089 fail:
2090 qemu_free(sn_tab);
2091 *psn_tab = NULL;
2092 return -ENOMEM;
2093 }
2094
2095 /*********************************************************/
2096 /* refcount handling */
2097
refcount_init(BlockDriverState * bs)2098 static int refcount_init(BlockDriverState *bs)
2099 {
2100 BDRVQcowState *s = bs->opaque;
2101 int ret, refcount_table_size2, i;
2102
2103 s->refcount_block_cache = qemu_malloc(s->cluster_size);
2104 if (!s->refcount_block_cache)
2105 goto fail;
2106 refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
2107 s->refcount_table = qemu_malloc(refcount_table_size2);
2108 if (!s->refcount_table)
2109 goto fail;
2110 if (s->refcount_table_size > 0) {
2111 ret = bdrv_pread(s->hd, s->refcount_table_offset,
2112 s->refcount_table, refcount_table_size2);
2113 if (ret != refcount_table_size2)
2114 goto fail;
2115 for(i = 0; i < s->refcount_table_size; i++)
2116 be64_to_cpus(&s->refcount_table[i]);
2117 }
2118 return 0;
2119 fail:
2120 return -ENOMEM;
2121 }
2122
refcount_close(BlockDriverState * bs)2123 static void refcount_close(BlockDriverState *bs)
2124 {
2125 BDRVQcowState *s = bs->opaque;
2126 qemu_free(s->refcount_block_cache);
2127 qemu_free(s->refcount_table);
2128 }
2129
2130
load_refcount_block(BlockDriverState * bs,int64_t refcount_block_offset)2131 static int load_refcount_block(BlockDriverState *bs,
2132 int64_t refcount_block_offset)
2133 {
2134 BDRVQcowState *s = bs->opaque;
2135 int ret;
2136 ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache,
2137 s->cluster_size);
2138 if (ret != s->cluster_size)
2139 return -EIO;
2140 s->refcount_block_cache_offset = refcount_block_offset;
2141 return 0;
2142 }
2143
get_refcount(BlockDriverState * bs,int64_t cluster_index)2144 static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
2145 {
2146 BDRVQcowState *s = bs->opaque;
2147 int refcount_table_index, block_index;
2148 int64_t refcount_block_offset;
2149
2150 refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
2151 if (refcount_table_index >= s->refcount_table_size)
2152 return 0;
2153 refcount_block_offset = s->refcount_table[refcount_table_index];
2154 if (!refcount_block_offset)
2155 return 0;
2156 if (refcount_block_offset != s->refcount_block_cache_offset) {
2157 /* better than nothing: return allocated if read error */
2158 if (load_refcount_block(bs, refcount_block_offset) < 0)
2159 return 1;
2160 }
2161 block_index = cluster_index &
2162 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
2163 return be16_to_cpu(s->refcount_block_cache[block_index]);
2164 }
2165
2166 /* return < 0 if error */
alloc_clusters_noref(BlockDriverState * bs,int64_t size)2167 static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
2168 {
2169 BDRVQcowState *s = bs->opaque;
2170 int i, nb_clusters;
2171
2172 nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
2173 for(;;) {
2174 if (get_refcount(bs, s->free_cluster_index) == 0) {
2175 s->free_cluster_index++;
2176 for(i = 1; i < nb_clusters; i++) {
2177 if (get_refcount(bs, s->free_cluster_index) != 0)
2178 goto not_found;
2179 s->free_cluster_index++;
2180 }
2181 #ifdef DEBUG_ALLOC2
2182 printf("alloc_clusters: size=%lld -> %lld\n",
2183 size,
2184 (s->free_cluster_index - nb_clusters) << s->cluster_bits);
2185 #endif
2186 return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
2187 } else {
2188 not_found:
2189 s->free_cluster_index++;
2190 }
2191 }
2192 }
2193
alloc_clusters(BlockDriverState * bs,int64_t size)2194 static int64_t alloc_clusters(BlockDriverState *bs, int64_t size)
2195 {
2196 int64_t offset;
2197
2198 offset = alloc_clusters_noref(bs, size);
2199 update_refcount(bs, offset, size, 1);
2200 return offset;
2201 }
2202
2203 /* only used to allocate compressed sectors. We try to allocate
2204 contiguous sectors. size must be <= cluster_size */
alloc_bytes(BlockDriverState * bs,int size)2205 static int64_t alloc_bytes(BlockDriverState *bs, int size)
2206 {
2207 BDRVQcowState *s = bs->opaque;
2208 int64_t offset, cluster_offset;
2209 int free_in_cluster;
2210
2211 assert(size > 0 && size <= s->cluster_size);
2212 if (s->free_byte_offset == 0) {
2213 s->free_byte_offset = alloc_clusters(bs, s->cluster_size);
2214 }
2215 redo:
2216 free_in_cluster = s->cluster_size -
2217 (s->free_byte_offset & (s->cluster_size - 1));
2218 if (size <= free_in_cluster) {
2219 /* enough space in current cluster */
2220 offset = s->free_byte_offset;
2221 s->free_byte_offset += size;
2222 free_in_cluster -= size;
2223 if (free_in_cluster == 0)
2224 s->free_byte_offset = 0;
2225 if ((offset & (s->cluster_size - 1)) != 0)
2226 update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
2227 } else {
2228 offset = alloc_clusters(bs, s->cluster_size);
2229 cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
2230 if ((cluster_offset + s->cluster_size) == offset) {
2231 /* we are lucky: contiguous data */
2232 offset = s->free_byte_offset;
2233 update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
2234 s->free_byte_offset += size;
2235 } else {
2236 s->free_byte_offset = offset;
2237 goto redo;
2238 }
2239 }
2240 return offset;
2241 }
2242
free_clusters(BlockDriverState * bs,int64_t offset,int64_t size)2243 static void free_clusters(BlockDriverState *bs,
2244 int64_t offset, int64_t size)
2245 {
2246 update_refcount(bs, offset, size, -1);
2247 }
2248
grow_refcount_table(BlockDriverState * bs,int min_size)2249 static int grow_refcount_table(BlockDriverState *bs, int min_size)
2250 {
2251 BDRVQcowState *s = bs->opaque;
2252 int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
2253 uint64_t *new_table;
2254 int64_t table_offset;
2255 uint64_t data64;
2256 uint32_t data32;
2257 int old_table_size;
2258 int64_t old_table_offset;
2259
2260 if (min_size <= s->refcount_table_size)
2261 return 0;
2262 /* compute new table size */
2263 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
2264 for(;;) {
2265 if (refcount_table_clusters == 0) {
2266 refcount_table_clusters = 1;
2267 } else {
2268 refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2;
2269 }
2270 new_table_size = refcount_table_clusters << (s->cluster_bits - 3);
2271 if (min_size <= new_table_size)
2272 break;
2273 }
2274 #ifdef DEBUG_ALLOC2
2275 printf("grow_refcount_table from %d to %d\n",
2276 s->refcount_table_size,
2277 new_table_size);
2278 #endif
2279 new_table_size2 = new_table_size * sizeof(uint64_t);
2280 new_table = qemu_mallocz(new_table_size2);
2281 if (!new_table)
2282 return -ENOMEM;
2283 memcpy(new_table, s->refcount_table,
2284 s->refcount_table_size * sizeof(uint64_t));
2285 for(i = 0; i < s->refcount_table_size; i++)
2286 cpu_to_be64s(&new_table[i]);
2287 /* Note: we cannot update the refcount now to avoid recursion */
2288 table_offset = alloc_clusters_noref(bs, new_table_size2);
2289 ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2);
2290 if (ret != new_table_size2)
2291 goto fail;
2292 for(i = 0; i < s->refcount_table_size; i++)
2293 be64_to_cpus(&new_table[i]);
2294
2295 data64 = cpu_to_be64(table_offset);
2296 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset),
2297 &data64, sizeof(data64)) != sizeof(data64))
2298 goto fail;
2299 data32 = cpu_to_be32(refcount_table_clusters);
2300 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_clusters),
2301 &data32, sizeof(data32)) != sizeof(data32))
2302 goto fail;
2303 qemu_free(s->refcount_table);
2304 old_table_offset = s->refcount_table_offset;
2305 old_table_size = s->refcount_table_size;
2306 s->refcount_table = new_table;
2307 s->refcount_table_size = new_table_size;
2308 s->refcount_table_offset = table_offset;
2309
2310 update_refcount(bs, table_offset, new_table_size2, 1);
2311 free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
2312 return 0;
2313 fail:
2314 free_clusters(bs, table_offset, new_table_size2);
2315 qemu_free(new_table);
2316 return -EIO;
2317 }
2318
2319 /* addend must be 1 or -1 */
2320 /* XXX: cache several refcount block clusters ? */
update_cluster_refcount(BlockDriverState * bs,int64_t cluster_index,int addend)2321 static int update_cluster_refcount(BlockDriverState *bs,
2322 int64_t cluster_index,
2323 int addend)
2324 {
2325 BDRVQcowState *s = bs->opaque;
2326 int64_t offset, refcount_block_offset;
2327 int ret, refcount_table_index, block_index, refcount;
2328 uint64_t data64;
2329
2330 refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
2331 if (refcount_table_index >= s->refcount_table_size) {
2332 if (addend < 0)
2333 return -EINVAL;
2334 ret = grow_refcount_table(bs, refcount_table_index + 1);
2335 if (ret < 0)
2336 return ret;
2337 }
2338 refcount_block_offset = s->refcount_table[refcount_table_index];
2339 if (!refcount_block_offset) {
2340 if (addend < 0)
2341 return -EINVAL;
2342 /* create a new refcount block */
2343 /* Note: we cannot update the refcount now to avoid recursion */
2344 offset = alloc_clusters_noref(bs, s->cluster_size);
2345 memset(s->refcount_block_cache, 0, s->cluster_size);
2346 ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size);
2347 if (ret != s->cluster_size)
2348 return -EINVAL;
2349 s->refcount_table[refcount_table_index] = offset;
2350 data64 = cpu_to_be64(offset);
2351 ret = bdrv_pwrite(s->hd, s->refcount_table_offset +
2352 refcount_table_index * sizeof(uint64_t),
2353 &data64, sizeof(data64));
2354 if (ret != sizeof(data64))
2355 return -EINVAL;
2356
2357 refcount_block_offset = offset;
2358 s->refcount_block_cache_offset = offset;
2359 update_refcount(bs, offset, s->cluster_size, 1);
2360 } else {
2361 if (refcount_block_offset != s->refcount_block_cache_offset) {
2362 if (load_refcount_block(bs, refcount_block_offset) < 0)
2363 return -EIO;
2364 }
2365 }
2366 /* we can update the count and save it */
2367 block_index = cluster_index &
2368 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
2369 refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
2370 refcount += addend;
2371 if (refcount < 0 || refcount > 0xffff)
2372 return -EINVAL;
2373 if (refcount == 0 && cluster_index < s->free_cluster_index) {
2374 s->free_cluster_index = cluster_index;
2375 }
2376 s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
2377 if (bdrv_pwrite(s->hd,
2378 refcount_block_offset + (block_index << REFCOUNT_SHIFT),
2379 &s->refcount_block_cache[block_index], 2) != 2)
2380 return -EIO;
2381 return refcount;
2382 }
2383
update_refcount(BlockDriverState * bs,int64_t offset,int64_t length,int addend)2384 static void update_refcount(BlockDriverState *bs,
2385 int64_t offset, int64_t length,
2386 int addend)
2387 {
2388 BDRVQcowState *s = bs->opaque;
2389 int64_t start, last, cluster_offset;
2390
2391 #ifdef DEBUG_ALLOC2
2392 printf("update_refcount: offset=%lld size=%lld addend=%d\n",
2393 offset, length, addend);
2394 #endif
2395 if (length <= 0)
2396 return;
2397 start = offset & ~(s->cluster_size - 1);
2398 last = (offset + length - 1) & ~(s->cluster_size - 1);
2399 for(cluster_offset = start; cluster_offset <= last;
2400 cluster_offset += s->cluster_size) {
2401 update_cluster_refcount(bs, cluster_offset >> s->cluster_bits, addend);
2402 }
2403 }
2404
2405 #ifdef DEBUG_ALLOC
inc_refcounts(BlockDriverState * bs,uint16_t * refcount_table,int refcount_table_size,int64_t offset,int64_t size)2406 static void inc_refcounts(BlockDriverState *bs,
2407 uint16_t *refcount_table,
2408 int refcount_table_size,
2409 int64_t offset, int64_t size)
2410 {
2411 BDRVQcowState *s = bs->opaque;
2412 int64_t start, last, cluster_offset;
2413 int k;
2414
2415 if (size <= 0)
2416 return;
2417
2418 start = offset & ~(s->cluster_size - 1);
2419 last = (offset + size - 1) & ~(s->cluster_size - 1);
2420 for(cluster_offset = start; cluster_offset <= last;
2421 cluster_offset += s->cluster_size) {
2422 k = cluster_offset >> s->cluster_bits;
2423 if (k < 0 || k >= refcount_table_size) {
2424 printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset);
2425 } else {
2426 if (++refcount_table[k] == 0) {
2427 printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset);
2428 }
2429 }
2430 }
2431 }
2432
check_refcounts_l1(BlockDriverState * bs,uint16_t * refcount_table,int refcount_table_size,int64_t l1_table_offset,int l1_size,int check_copied)2433 static int check_refcounts_l1(BlockDriverState *bs,
2434 uint16_t *refcount_table,
2435 int refcount_table_size,
2436 int64_t l1_table_offset, int l1_size,
2437 int check_copied)
2438 {
2439 BDRVQcowState *s = bs->opaque;
2440 uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
2441 int l2_size, i, j, nb_csectors, refcount;
2442
2443 l2_table = NULL;
2444 l1_size2 = l1_size * sizeof(uint64_t);
2445
2446 inc_refcounts(bs, refcount_table, refcount_table_size,
2447 l1_table_offset, l1_size2);
2448
2449 l1_table = qemu_malloc(l1_size2);
2450 if (!l1_table)
2451 goto fail;
2452 if (bdrv_pread(s->hd, l1_table_offset,
2453 l1_table, l1_size2) != l1_size2)
2454 goto fail;
2455 for(i = 0;i < l1_size; i++)
2456 be64_to_cpus(&l1_table[i]);
2457
2458 l2_size = s->l2_size * sizeof(uint64_t);
2459 l2_table = qemu_malloc(l2_size);
2460 if (!l2_table)
2461 goto fail;
2462 for(i = 0; i < l1_size; i++) {
2463 l2_offset = l1_table[i];
2464 if (l2_offset) {
2465 if (check_copied) {
2466 refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
2467 if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
2468 printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
2469 l2_offset, refcount);
2470 }
2471 }
2472 l2_offset &= ~QCOW_OFLAG_COPIED;
2473 if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
2474 goto fail;
2475 for(j = 0; j < s->l2_size; j++) {
2476 offset = be64_to_cpu(l2_table[j]);
2477 if (offset != 0) {
2478 if (offset & QCOW_OFLAG_COMPRESSED) {
2479 if (offset & QCOW_OFLAG_COPIED) {
2480 printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
2481 offset >> s->cluster_bits);
2482 offset &= ~QCOW_OFLAG_COPIED;
2483 }
2484 nb_csectors = ((offset >> s->csize_shift) &
2485 s->csize_mask) + 1;
2486 offset &= s->cluster_offset_mask;
2487 inc_refcounts(bs, refcount_table,
2488 refcount_table_size,
2489 offset & ~511, nb_csectors * 512);
2490 } else {
2491 if (check_copied) {
2492 refcount = get_refcount(bs, (offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
2493 if ((refcount == 1) != ((offset & QCOW_OFLAG_COPIED) != 0)) {
2494 printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
2495 offset, refcount);
2496 }
2497 }
2498 offset &= ~QCOW_OFLAG_COPIED;
2499 inc_refcounts(bs, refcount_table,
2500 refcount_table_size,
2501 offset, s->cluster_size);
2502 }
2503 }
2504 }
2505 inc_refcounts(bs, refcount_table,
2506 refcount_table_size,
2507 l2_offset,
2508 s->cluster_size);
2509 }
2510 }
2511 qemu_free(l1_table);
2512 qemu_free(l2_table);
2513 return 0;
2514 fail:
2515 printf("ERROR: I/O error in check_refcounts_l1\n");
2516 qemu_free(l1_table);
2517 qemu_free(l2_table);
2518 return -EIO;
2519 }
2520
check_refcounts(BlockDriverState * bs)2521 static void check_refcounts(BlockDriverState *bs)
2522 {
2523 BDRVQcowState *s = bs->opaque;
2524 int64_t size;
2525 int nb_clusters, refcount1, refcount2, i;
2526 QCowSnapshot *sn;
2527 uint16_t *refcount_table;
2528
2529 size = bdrv_getlength(s->hd);
2530 nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
2531 refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
2532
2533 /* header */
2534 inc_refcounts(bs, refcount_table, nb_clusters,
2535 0, s->cluster_size);
2536
2537 check_refcounts_l1(bs, refcount_table, nb_clusters,
2538 s->l1_table_offset, s->l1_size, 1);
2539
2540 /* snapshots */
2541 for(i = 0; i < s->nb_snapshots; i++) {
2542 sn = s->snapshots + i;
2543 check_refcounts_l1(bs, refcount_table, nb_clusters,
2544 sn->l1_table_offset, sn->l1_size, 0);
2545 }
2546 inc_refcounts(bs, refcount_table, nb_clusters,
2547 s->snapshots_offset, s->snapshots_size);
2548
2549 /* refcount data */
2550 inc_refcounts(bs, refcount_table, nb_clusters,
2551 s->refcount_table_offset,
2552 s->refcount_table_size * sizeof(uint64_t));
2553 for(i = 0; i < s->refcount_table_size; i++) {
2554 int64_t offset;
2555 offset = s->refcount_table[i];
2556 if (offset != 0) {
2557 inc_refcounts(bs, refcount_table, nb_clusters,
2558 offset, s->cluster_size);
2559 }
2560 }
2561
2562 /* compare ref counts */
2563 for(i = 0; i < nb_clusters; i++) {
2564 refcount1 = get_refcount(bs, i);
2565 refcount2 = refcount_table[i];
2566 if (refcount1 != refcount2)
2567 printf("ERROR cluster %d refcount=%d reference=%d\n",
2568 i, refcount1, refcount2);
2569 }
2570
2571 qemu_free(refcount_table);
2572 }
2573
2574 #if 0
2575 static void dump_refcounts(BlockDriverState *bs)
2576 {
2577 BDRVQcowState *s = bs->opaque;
2578 int64_t nb_clusters, k, k1, size;
2579 int refcount;
2580
2581 size = bdrv_getlength(s->hd);
2582 nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
2583 for(k = 0; k < nb_clusters;) {
2584 k1 = k;
2585 refcount = get_refcount(bs, k);
2586 k++;
2587 while (k < nb_clusters && get_refcount(bs, k) == refcount)
2588 k++;
2589 printf("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
2590 }
2591 }
2592 #endif
2593 #endif
2594
2595 BlockDriver bdrv_qcow2 = {
2596 "qcow2",
2597 sizeof(BDRVQcowState),
2598 qcow_probe,
2599 qcow_open,
2600 NULL,
2601 NULL,
2602 qcow_close,
2603 qcow_create,
2604 qcow_flush,
2605 qcow_is_allocated,
2606 qcow_set_key,
2607 qcow_make_empty,
2608
2609 .bdrv_aio_read = qcow_aio_read,
2610 .bdrv_aio_write = qcow_aio_write,
2611 .bdrv_aio_cancel = qcow_aio_cancel,
2612 .aiocb_size = sizeof(QCowAIOCB),
2613 .bdrv_write_compressed = qcow_write_compressed,
2614
2615 .bdrv_snapshot_create = qcow_snapshot_create,
2616 .bdrv_snapshot_goto = qcow_snapshot_goto,
2617 .bdrv_snapshot_delete = qcow_snapshot_delete,
2618 .bdrv_snapshot_list = qcow_snapshot_list,
2619 .bdrv_get_info = qcow_get_info,
2620 };
2621