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[qemu.git] / block-qcow2.c
CommitLineData
585f8587
FB		 1/*
2 * Block driver for the QCOW version 2 format
5fafdf24 3 *
585f8587 4 * Copyright (c) 2004-2006 Fabrice Bellard
5fafdf24 5 *
585f8587
FB		 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 */
faf07963 24#include "qemu-common.h"
585f8587
FB		 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.
5fafdf24 37 - Size of compressed clusters is stored in sectors to reduce bit usage
585f8587
FB		 38 in the cluster offsets.
39 - Support for storing additional data (such as the VM state) in the
3b46e624 40 snapshots.
585f8587
FB		 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
5fafdf24 48
585f8587
FB		 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/* indicate that the refcount of the referenced cluster is exactly one. */
56#define QCOW_OFLAG_COPIED (1LL << 63)
57/* indicate that the cluster is compressed (they never have the copied flag) */
58#define QCOW_OFLAG_COMPRESSED (1LL << 62)
59
60#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
61
62#ifndef offsetof
63#define offsetof(type, field) ((size_t) &((type *)0)->field)
64#endif
65
66typedef struct QCowHeader {
67 uint32_t magic;
68 uint32_t version;
69 uint64_t backing_file_offset;
70 uint32_t backing_file_size;
71 uint32_t cluster_bits;
72 uint64_t size; /* in bytes */
73 uint32_t crypt_method;
74 uint32_t l1_size; /* XXX: save number of clusters instead ? */
75 uint64_t l1_table_offset;
76 uint64_t refcount_table_offset;
77 uint32_t refcount_table_clusters;
78 uint32_t nb_snapshots;
79 uint64_t snapshots_offset;
80} QCowHeader;
81
82typedef struct __attribute__((packed)) QCowSnapshotHeader {
83 /* header is 8 byte aligned */
84 uint64_t l1_table_offset;
85
86 uint32_t l1_size;
87 uint16_t id_str_size;
88 uint16_t name_size;
89
90 uint32_t date_sec;
91 uint32_t date_nsec;
92
93 uint64_t vm_clock_nsec;
94
95 uint32_t vm_state_size;
96 uint32_t extra_data_size; /* for extension */
97 /* extra data follows */
98 /* id_str follows */
99 /* name follows */
100} QCowSnapshotHeader;
101
102#define L2_CACHE_SIZE 16
103
104typedef struct QCowSnapshot {
105 uint64_t l1_table_offset;
106 uint32_t l1_size;
107 char *id_str;
108 char *name;
109 uint32_t vm_state_size;
110 uint32_t date_sec;
111 uint32_t date_nsec;
112 uint64_t vm_clock_nsec;
113} QCowSnapshot;
114
115typedef struct BDRVQcowState {
116 BlockDriverState *hd;
117 int cluster_bits;
118 int cluster_size;
119 int cluster_sectors;
120 int l2_bits;
121 int l2_size;
122 int l1_size;
123 int l1_vm_state_index;
124 int csize_shift;
125 int csize_mask;
126 uint64_t cluster_offset_mask;
127 uint64_t l1_table_offset;
128 uint64_t *l1_table;
129 uint64_t *l2_cache;
130 uint64_t l2_cache_offsets[L2_CACHE_SIZE];
131 uint32_t l2_cache_counts[L2_CACHE_SIZE];
132 uint8_t *cluster_cache;
133 uint8_t *cluster_data;
134 uint64_t cluster_cache_offset;
135
136 uint64_t *refcount_table;
137 uint64_t refcount_table_offset;
138 uint32_t refcount_table_size;
139 uint64_t refcount_block_cache_offset;
140 uint16_t *refcount_block_cache;
141 int64_t free_cluster_index;
142 int64_t free_byte_offset;
143
144 uint32_t crypt_method; /* current crypt method, 0 if no key yet */
145 uint32_t crypt_method_header;
146 AES_KEY aes_encrypt_key;
147 AES_KEY aes_decrypt_key;
148 uint64_t snapshots_offset;
149 int snapshots_size;
150 int nb_snapshots;
151 QCowSnapshot *snapshots;
152} BDRVQcowState;
153
154static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
5fafdf24 155static int qcow_read(BlockDriverState *bs, int64_t sector_num,
585f8587
FB		 156 uint8_t *buf, int nb_sectors);
157static int qcow_read_snapshots(BlockDriverState *bs);
158static void qcow_free_snapshots(BlockDriverState *bs);
159static int refcount_init(BlockDriverState *bs);
160static void refcount_close(BlockDriverState *bs);
161static int get_refcount(BlockDriverState *bs, int64_t cluster_index);
5fafdf24 162static int update_cluster_refcount(BlockDriverState *bs,
585f8587
FB		 163 int64_t cluster_index,
164 int addend);
5fafdf24
TS		 165static void update_refcount(BlockDriverState *bs,
166 int64_t offset, int64_t length,
585f8587
FB		 167 int addend);
168static int64_t alloc_clusters(BlockDriverState *bs, int64_t size);
169static int64_t alloc_bytes(BlockDriverState *bs, int size);
5fafdf24 170static void free_clusters(BlockDriverState *bs,
585f8587
FB		 171 int64_t offset, int64_t size);
172#ifdef DEBUG_ALLOC
173static void check_refcounts(BlockDriverState *bs);
174#endif
175
176static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
177{
178 const QCowHeader *cow_header = (const void *)buf;
3b46e624 179
585f8587
FB		 180 if (buf_size >= sizeof(QCowHeader) &&
181 be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
5fafdf24 182 be32_to_cpu(cow_header->version) == QCOW_VERSION)
585f8587
FB		 183 return 100;
184 else
185 return 0;
186}
187
188static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
189{
190 BDRVQcowState *s = bs->opaque;
191 int len, i, shift, ret;
192 QCowHeader header;
193
b5eff355 194 ret = bdrv_file_open(&s->hd, filename, flags);
585f8587
FB		 195 if (ret < 0)
196 return ret;
197 if (bdrv_pread(s->hd, 0, &header, sizeof(header)) != sizeof(header))
198 goto fail;
199 be32_to_cpus(&header.magic);
200 be32_to_cpus(&header.version);
201 be64_to_cpus(&header.backing_file_offset);
202 be32_to_cpus(&header.backing_file_size);
203 be64_to_cpus(&header.size);
204 be32_to_cpus(&header.cluster_bits);
205 be32_to_cpus(&header.crypt_method);
206 be64_to_cpus(&header.l1_table_offset);
207 be32_to_cpus(&header.l1_size);
208 be64_to_cpus(&header.refcount_table_offset);
209 be32_to_cpus(&header.refcount_table_clusters);
210 be64_to_cpus(&header.snapshots_offset);
211 be32_to_cpus(&header.nb_snapshots);
3b46e624 212
585f8587
FB		 213 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
214 goto fail;
5fafdf24
TS		 215 if (header.size <= 1 ||
216 header.cluster_bits < 9 ||
585f8587
FB		 217 header.cluster_bits > 16)
218 goto fail;
219 if (header.crypt_method > QCOW_CRYPT_AES)
220 goto fail;
221 s->crypt_method_header = header.crypt_method;
222 if (s->crypt_method_header)
223 bs->encrypted = 1;
224 s->cluster_bits = header.cluster_bits;
225 s->cluster_size = 1 << s->cluster_bits;
226 s->cluster_sectors = 1 << (s->cluster_bits - 9);
227 s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
228 s->l2_size = 1 << s->l2_bits;
229 bs->total_sectors = header.size / 512;
230 s->csize_shift = (62 - (s->cluster_bits - 8));
231 s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
232 s->cluster_offset_mask = (1LL << s->csize_shift) - 1;
233 s->refcount_table_offset = header.refcount_table_offset;
5fafdf24 234 s->refcount_table_size =
585f8587
FB		 235 header.refcount_table_clusters << (s->cluster_bits - 3);
236
237 s->snapshots_offset = header.snapshots_offset;
238 s->nb_snapshots = header.nb_snapshots;
239
240 /* read the level 1 table */
241 s->l1_size = header.l1_size;
242 shift = s->cluster_bits + s->l2_bits;
243 s->l1_vm_state_index = (header.size + (1LL << shift) - 1) >> shift;
244 /* the L1 table must contain at least enough entries to put
245 header.size bytes */
246 if (s->l1_size < s->l1_vm_state_index)
247 goto fail;
248 s->l1_table_offset = header.l1_table_offset;
249 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
250 if (!s->l1_table)
251 goto fail;
5fafdf24 252 if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) !=
585f8587
FB		 253 s->l1_size * sizeof(uint64_t))
254 goto fail;
255 for(i = 0;i < s->l1_size; i++) {
256 be64_to_cpus(&s->l1_table[i]);
257 }
258 /* alloc L2 cache */
259 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
260 if (!s->l2_cache)
261 goto fail;
262 s->cluster_cache = qemu_malloc(s->cluster_size);
263 if (!s->cluster_cache)
264 goto fail;
265 /* one more sector for decompressed data alignment */
266 s->cluster_data = qemu_malloc(s->cluster_size + 512);
267 if (!s->cluster_data)
268 goto fail;
269 s->cluster_cache_offset = -1;
3b46e624 270
585f8587
FB		 271 if (refcount_init(bs) < 0)
272 goto fail;
273
274 /* read the backing file name */
275 if (header.backing_file_offset != 0) {
276 len = header.backing_file_size;
277 if (len > 1023)
278 len = 1023;
279 if (bdrv_pread(s->hd, header.backing_file_offset, bs->backing_file, len) != len)
280 goto fail;
281 bs->backing_file[len] = '\0';
282 }
283 if (qcow_read_snapshots(bs) < 0)
284 goto fail;
285
286#ifdef DEBUG_ALLOC
287 check_refcounts(bs);
288#endif
289 return 0;
290
291 fail:
292 qcow_free_snapshots(bs);
293 refcount_close(bs);
294 qemu_free(s->l1_table);
295 qemu_free(s->l2_cache);
296 qemu_free(s->cluster_cache);
297 qemu_free(s->cluster_data);
298 bdrv_delete(s->hd);
299 return -1;
300}
301
302static int qcow_set_key(BlockDriverState *bs, const char *key)
303{
304 BDRVQcowState *s = bs->opaque;
305 uint8_t keybuf[16];
306 int len, i;
3b46e624 307
585f8587
FB		 308 memset(keybuf, 0, 16);
309 len = strlen(key);
310 if (len > 16)
311 len = 16;
312 /* XXX: we could compress the chars to 7 bits to increase
313 entropy */
314 for(i = 0;i < len;i++) {
315 keybuf[i] = key[i];
316 }
317 s->crypt_method = s->crypt_method_header;
318
319 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
320 return -1;
321 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
322 return -1;
323#if 0
324 /* test */
325 {
326 uint8_t in[16];
327 uint8_t out[16];
328 uint8_t tmp[16];
329 for(i=0;i<16;i++)
330 in[i] = i;
331 AES_encrypt(in, tmp, &s->aes_encrypt_key);
332 AES_decrypt(tmp, out, &s->aes_decrypt_key);
333 for(i = 0; i < 16; i++)
334 printf(" %02x", tmp[i]);
335 printf("\n");
336 for(i = 0; i < 16; i++)
337 printf(" %02x", out[i]);
338 printf("\n");
339 }
340#endif
341 return 0;
342}
343
344/* The crypt function is compatible with the linux cryptoloop
345 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
346 supported */
347static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
348 uint8_t *out_buf, const uint8_t *in_buf,
349 int nb_sectors, int enc,
350 const AES_KEY *key)
351{
352 union {
353 uint64_t ll[2];
354 uint8_t b[16];
355 } ivec;
356 int i;
357
358 for(i = 0; i < nb_sectors; i++) {
359 ivec.ll[0] = cpu_to_le64(sector_num);
360 ivec.ll[1] = 0;
5fafdf24 361 AES_cbc_encrypt(in_buf, out_buf, 512, key,
585f8587
FB		 362 ivec.b, enc);
363 sector_num++;
364 in_buf += 512;
365 out_buf += 512;
366 }
367}
368
369static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
370 uint64_t cluster_offset, int n_start, int n_end)
371{
372 BDRVQcowState *s = bs->opaque;
373 int n, ret;
374
375 n = n_end - n_start;
376 if (n <= 0)
377 return 0;
378 ret = qcow_read(bs, start_sect + n_start, s->cluster_data, n);
379 if (ret < 0)
380 return ret;
381 if (s->crypt_method) {
5fafdf24
TS		 382 encrypt_sectors(s, start_sect + n_start,
383 s->cluster_data,
585f8587
FB		 384 s->cluster_data, n, 1,
385 &s->aes_encrypt_key);
386 }
5fafdf24 387 ret = bdrv_write(s->hd, (cluster_offset >> 9) + n_start,
585f8587
FB		 388 s->cluster_data, n);
389 if (ret < 0)
390 return ret;
391 return 0;
392}
393
394static void l2_cache_reset(BlockDriverState *bs)
395{
396 BDRVQcowState *s = bs->opaque;
397
398 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
399 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
400 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
401}
402
403static inline int l2_cache_new_entry(BlockDriverState *bs)
404{
405 BDRVQcowState *s = bs->opaque;
406 uint32_t min_count;
407 int min_index, i;
408
409 /* find a new entry in the least used one */
410 min_index = 0;
411 min_count = 0xffffffff;
412 for(i = 0; i < L2_CACHE_SIZE; i++) {
413 if (s->l2_cache_counts[i] < min_count) {
414 min_count = s->l2_cache_counts[i];
415 min_index = i;
416 }
417 }
418 return min_index;
419}
420
421static int64_t align_offset(int64_t offset, int n)
422{
423 offset = (offset + n - 1) & ~(n - 1);
424 return offset;
425}
426
427static int grow_l1_table(BlockDriverState *bs, int min_size)
428{
429 BDRVQcowState *s = bs->opaque;
430 int new_l1_size, new_l1_size2, ret, i;
431 uint64_t *new_l1_table;
432 uint64_t new_l1_table_offset;
433 uint64_t data64;
434 uint32_t data32;
435
436 new_l1_size = s->l1_size;
437 if (min_size <= new_l1_size)
438 return 0;
439 while (min_size > new_l1_size) {
440 new_l1_size = (new_l1_size * 3 + 1) / 2;
441 }
442#ifdef DEBUG_ALLOC2
443 printf("grow l1_table from %d to %d\n", s->l1_size, new_l1_size);
444#endif
445
446 new_l1_size2 = sizeof(uint64_t) * new_l1_size;
447 new_l1_table = qemu_mallocz(new_l1_size2);
448 if (!new_l1_table)
449 return -ENOMEM;
450 memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
451
452 /* write new table (align to cluster) */
453 new_l1_table_offset = alloc_clusters(bs, new_l1_size2);
3b46e624 454
585f8587
FB		 455 for(i = 0; i < s->l1_size; i++)
456 new_l1_table[i] = cpu_to_be64(new_l1_table[i]);
457 ret = bdrv_pwrite(s->hd, new_l1_table_offset, new_l1_table, new_l1_size2);
458 if (ret != new_l1_size2)
459 goto fail;
460 for(i = 0; i < s->l1_size; i++)
461 new_l1_table[i] = be64_to_cpu(new_l1_table[i]);
3b46e624 462
585f8587
FB		 463 /* set new table */
464 data64 = cpu_to_be64(new_l1_table_offset);
465 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_table_offset),
466 &data64, sizeof(data64)) != sizeof(data64))
467 goto fail;
468 data32 = cpu_to_be32(new_l1_size);
469 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, l1_size),
470 &data32, sizeof(data32)) != sizeof(data32))
471 goto fail;
472 qemu_free(s->l1_table);
473 free_clusters(bs, s->l1_table_offset, s->l1_size * sizeof(uint64_t));
474 s->l1_table_offset = new_l1_table_offset;
475 s->l1_table = new_l1_table;
476 s->l1_size = new_l1_size;
477 return 0;
478 fail:
479 qemu_free(s->l1_table);
480 return -EIO;
481}
482
483/* 'allocate' is:
484 *
485 * 0 not to allocate.
486 *
487 * 1 to allocate a normal cluster (for sector indexes 'n_start' to
488 * 'n_end')
489 *
490 * 2 to allocate a compressed cluster of size
491 * 'compressed_size'. 'compressed_size' must be > 0 and <
5fafdf24 492 * cluster_size
585f8587
FB		 493 *
494 * return 0 if not allocated.
495 */
496static uint64_t get_cluster_offset(BlockDriverState *bs,
497 uint64_t offset, int allocate,
498 int compressed_size,
499 int n_start, int n_end)
500{
501 BDRVQcowState *s = bs->opaque;
502 int min_index, i, j, l1_index, l2_index, ret;
503 uint64_t l2_offset, *l2_table, cluster_offset, tmp, old_l2_offset;
3b46e624 504
585f8587
FB		 505 l1_index = offset >> (s->l2_bits + s->cluster_bits);
506 if (l1_index >= s->l1_size) {
507 /* outside l1 table is allowed: we grow the table if needed */
508 if (!allocate)
509 return 0;
510 if (grow_l1_table(bs, l1_index + 1) < 0)
511 return 0;
512 }
513 l2_offset = s->l1_table[l1_index];
514 if (!l2_offset) {
515 if (!allocate)
516 return 0;
517 l2_allocate:
518 old_l2_offset = l2_offset;
519 /* allocate a new l2 entry */
520 l2_offset = alloc_clusters(bs, s->l2_size * sizeof(uint64_t));
521 /* update the L1 entry */
522 s->l1_table[l1_index] = l2_offset | QCOW_OFLAG_COPIED;
523 tmp = cpu_to_be64(l2_offset | QCOW_OFLAG_COPIED);
5fafdf24 524 if (bdrv_pwrite(s->hd, s->l1_table_offset + l1_index * sizeof(tmp),
585f8587
FB		 525 &tmp, sizeof(tmp)) != sizeof(tmp))
526 return 0;
527 min_index = l2_cache_new_entry(bs);
528 l2_table = s->l2_cache + (min_index << s->l2_bits);
529
530 if (old_l2_offset == 0) {
531 memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
532 } else {
5fafdf24 533 if (bdrv_pread(s->hd, old_l2_offset,
585f8587
FB		 534 l2_table, s->l2_size * sizeof(uint64_t)) !=
535 s->l2_size * sizeof(uint64_t))
536 return 0;
537 }
5fafdf24 538 if (bdrv_pwrite(s->hd, l2_offset,
585f8587
FB		 539 l2_table, s->l2_size * sizeof(uint64_t)) !=
540 s->l2_size * sizeof(uint64_t))
541 return 0;
542 } else {
543 if (!(l2_offset & QCOW_OFLAG_COPIED)) {
544 if (allocate) {
545 free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
546 goto l2_allocate;
547 }
548 } else {
549 l2_offset &= ~QCOW_OFLAG_COPIED;
550 }
551 for(i = 0; i < L2_CACHE_SIZE; i++) {
552 if (l2_offset == s->l2_cache_offsets[i]) {
553 /* increment the hit count */
554 if (++s->l2_cache_counts[i] == 0xffffffff) {
555 for(j = 0; j < L2_CACHE_SIZE; j++) {
556 s->l2_cache_counts[j] >>= 1;
557 }
558 }
559 l2_table = s->l2_cache + (i << s->l2_bits);
560 goto found;
561 }
562 }
563 /* not found: load a new entry in the least used one */
564 min_index = l2_cache_new_entry(bs);
565 l2_table = s->l2_cache + (min_index << s->l2_bits);
5fafdf24 566 if (bdrv_pread(s->hd, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
585f8587
FB		 567 s->l2_size * sizeof(uint64_t))
568 return 0;
569 }
570 s->l2_cache_offsets[min_index] = l2_offset;
571 s->l2_cache_counts[min_index] = 1;
572 found:
573 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
574 cluster_offset = be64_to_cpu(l2_table[l2_index]);
575 if (!cluster_offset) {
576 if (!allocate)
577 return cluster_offset;
578 } else if (!(cluster_offset & QCOW_OFLAG_COPIED)) {
579 if (!allocate)
580 return cluster_offset;
581 /* free the cluster */
582 if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
583 int nb_csectors;
5fafdf24 584 nb_csectors = ((cluster_offset >> s->csize_shift) &
585f8587
FB		 585 s->csize_mask) + 1;
586 free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
587 nb_csectors * 512);
588 } else {
589 free_clusters(bs, cluster_offset, s->cluster_size);
590 }
591 } else {
592 cluster_offset &= ~QCOW_OFLAG_COPIED;
593 return cluster_offset;
594 }
595 if (allocate == 1) {
596 /* allocate a new cluster */
597 cluster_offset = alloc_clusters(bs, s->cluster_size);
598
599 /* we must initialize the cluster content which won't be
600 written */
601 if ((n_end - n_start) < s->cluster_sectors) {
602 uint64_t start_sect;
3b46e624 603
585f8587
FB		 604 start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
605 ret = copy_sectors(bs, start_sect,
606 cluster_offset, 0, n_start);
607 if (ret < 0)
608 return 0;
609 ret = copy_sectors(bs, start_sect,
610 cluster_offset, n_end, s->cluster_sectors);
611 if (ret < 0)
612 return 0;
613 }
614 tmp = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED);
615 } else {
616 int nb_csectors;
617 cluster_offset = alloc_bytes(bs, compressed_size);
5fafdf24 618 nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
585f8587 619 (cluster_offset >> 9);
5fafdf24 620 cluster_offset |= QCOW_OFLAG_COMPRESSED |
585f8587
FB		 621 ((uint64_t)nb_csectors << s->csize_shift);
622 /* compressed clusters never have the copied flag */
623 tmp = cpu_to_be64(cluster_offset);
624 }
625 /* update L2 table */
626 l2_table[l2_index] = tmp;
5fafdf24 627 if (bdrv_pwrite(s->hd,
585f8587
FB		 628 l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
629 return 0;
630 return cluster_offset;
631}
632
5fafdf24 633static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
585f8587
FB		 634 int nb_sectors, int *pnum)
635{
636 BDRVQcowState *s = bs->opaque;
637 int index_in_cluster, n;
638 uint64_t cluster_offset;
639
640 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
641 index_in_cluster = sector_num & (s->cluster_sectors - 1);
642 n = s->cluster_sectors - index_in_cluster;
643 if (n > nb_sectors)
644 n = nb_sectors;
645 *pnum = n;
646 return (cluster_offset != 0);
647}
648
649static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
650 const uint8_t *buf, int buf_size)
651{
652 z_stream strm1, *strm = &strm1;
653 int ret, out_len;
654
655 memset(strm, 0, sizeof(*strm));
656
657 strm->next_in = (uint8_t *)buf;
658 strm->avail_in = buf_size;
659 strm->next_out = out_buf;
660 strm->avail_out = out_buf_size;
661
662 ret = inflateInit2(strm, -12);
663 if (ret != Z_OK)
664 return -1;
665 ret = inflate(strm, Z_FINISH);
666 out_len = strm->next_out - out_buf;
667 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
668 out_len != out_buf_size) {
669 inflateEnd(strm);
670 return -1;
671 }
672 inflateEnd(strm);
673 return 0;
674}
3b46e624 675
585f8587
FB		 676static int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset)
677{
678 int ret, csize, nb_csectors, sector_offset;
679 uint64_t coffset;
680
681 coffset = cluster_offset & s->cluster_offset_mask;
682 if (s->cluster_cache_offset != coffset) {
683 nb_csectors = ((cluster_offset >> s->csize_shift) & s->csize_mask) + 1;
684 sector_offset = coffset & 511;
685 csize = nb_csectors * 512 - sector_offset;
686 ret = bdrv_read(s->hd, coffset >> 9, s->cluster_data, nb_csectors);
687 if (ret < 0) {
688 return -1;
689 }
690 if (decompress_buffer(s->cluster_cache, s->cluster_size,
691 s->cluster_data + sector_offset, csize) < 0) {
692 return -1;
693 }
694 s->cluster_cache_offset = coffset;
695 }
696 return 0;
697}
698
a9465922 699/* handle reading after the end of the backing file */
5fafdf24 700static int backing_read1(BlockDriverState *bs,
a9465922
FB		 701 int64_t sector_num, uint8_t *buf, int nb_sectors)
702{
703 int n1;
704 if ((sector_num + nb_sectors) <= bs->total_sectors)
705 return nb_sectors;
706 if (sector_num >= bs->total_sectors)
707 n1 = 0;
708 else
709 n1 = bs->total_sectors - sector_num;
710 memset(buf + n1 * 512, 0, 512 * (nb_sectors - n1));
711 return n1;
712}
713
5fafdf24 714static int qcow_read(BlockDriverState *bs, int64_t sector_num,
585f8587
FB		 715 uint8_t *buf, int nb_sectors)
716{
717 BDRVQcowState *s = bs->opaque;
a9465922 718 int ret, index_in_cluster, n, n1;
585f8587 719 uint64_t cluster_offset;
3b46e624 720
585f8587
FB		 721 while (nb_sectors > 0) {
722 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
723 index_in_cluster = sector_num & (s->cluster_sectors - 1);
724 n = s->cluster_sectors - index_in_cluster;
725 if (n > nb_sectors)
726 n = nb_sectors;
727 if (!cluster_offset) {
728 if (bs->backing_hd) {
729 /* read from the base image */
a9465922
FB		 730 n1 = backing_read1(bs->backing_hd, sector_num, buf, n);
731 if (n1 > 0) {
732 ret = bdrv_read(bs->backing_hd, sector_num, buf, n1);
733 if (ret < 0)
734 return -1;
735 }
585f8587
FB		 736 } else {
737 memset(buf, 0, 512 * n);
738 }
739 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
740 if (decompress_cluster(s, cluster_offset) < 0)
741 return -1;
742 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
743 } else {
744 ret = bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
5fafdf24 745 if (ret != n * 512)
585f8587
FB		 746 return -1;
747 if (s->crypt_method) {
5fafdf24 748 encrypt_sectors(s, sector_num, buf, buf, n, 0,
585f8587
FB		 749 &s->aes_decrypt_key);
750 }
751 }
752 nb_sectors -= n;
753 sector_num += n;
754 buf += n * 512;
755 }
756 return 0;
757}
758
5fafdf24 759static int qcow_write(BlockDriverState *bs, int64_t sector_num,
585f8587
FB		 760 const uint8_t *buf, int nb_sectors)
761{
762 BDRVQcowState *s = bs->opaque;
763 int ret, index_in_cluster, n;
764 uint64_t cluster_offset;
3b46e624 765
585f8587
FB		 766 while (nb_sectors > 0) {
767 index_in_cluster = sector_num & (s->cluster_sectors - 1);
768 n = s->cluster_sectors - index_in_cluster;
769 if (n > nb_sectors)
770 n = nb_sectors;
5fafdf24
TS		 771 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
772 index_in_cluster,
585f8587
FB		 773 index_in_cluster + n);
774 if (!cluster_offset)
775 return -1;
776 if (s->crypt_method) {
777 encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
778 &s->aes_encrypt_key);
5fafdf24 779 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
585f8587
FB		 780 s->cluster_data, n * 512);
781 } else {
782 ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
783 }
5fafdf24 784 if (ret != n * 512)
585f8587
FB		 785 return -1;
786 nb_sectors -= n;
787 sector_num += n;
788 buf += n * 512;
789 }
790 s->cluster_cache_offset = -1; /* disable compressed cache */
791 return 0;
792}
793
ce1a14dc
PB		 794typedef struct QCowAIOCB {
795 BlockDriverAIOCB common;
585f8587
FB		 796 int64_t sector_num;
797 uint8_t *buf;
798 int nb_sectors;
799 int n;
800 uint64_t cluster_offset;
5fafdf24 801 uint8_t *cluster_data;
585f8587 802 BlockDriverAIOCB *hd_aiocb;
585f8587
FB		 803} QCowAIOCB;
804
585f8587
FB		 805static void qcow_aio_read_cb(void *opaque, int ret)
806{
ce1a14dc
PB		 807 QCowAIOCB *acb = opaque;
808 BlockDriverState *bs = acb->common.bs;
585f8587 809 BDRVQcowState *s = bs->opaque;
a9465922 810 int index_in_cluster, n1;
585f8587 811
ce1a14dc 812 acb->hd_aiocb = NULL;
585f8587
FB		 813 if (ret < 0) {
814 fail:
ce1a14dc
PB		 815 acb->common.cb(acb->common.opaque, ret);
816 qemu_aio_release(acb);
585f8587
FB		 817 return;
818 }
819
820 redo:
821 /* post process the read buffer */
ce1a14dc 822 if (!acb->cluster_offset) {
585f8587 823 /* nothing to do */
ce1a14dc 824 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
585f8587
FB		 825 /* nothing to do */
826 } else {
827 if (s->crypt_method) {
5fafdf24
TS		 828 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
829 acb->n, 0,
585f8587
FB		 830 &s->aes_decrypt_key);
831 }
832 }
833
ce1a14dc
PB		 834 acb->nb_sectors -= acb->n;
835 acb->sector_num += acb->n;
836 acb->buf += acb->n * 512;
585f8587 837
ce1a14dc 838 if (acb->nb_sectors == 0) {
585f8587 839 /* request completed */
ce1a14dc
PB		 840 acb->common.cb(acb->common.opaque, 0);
841 qemu_aio_release(acb);
585f8587
FB		 842 return;
843 }
3b46e624 844
585f8587 845 /* prepare next AIO request */
5fafdf24 846 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
ce1a14dc
PB		 847 0, 0, 0, 0);
848 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
849 acb->n = s->cluster_sectors - index_in_cluster;
850 if (acb->n > acb->nb_sectors)
851 acb->n = acb->nb_sectors;
852
853 if (!acb->cluster_offset) {
585f8587
FB		 854 if (bs->backing_hd) {
855 /* read from the base image */
5fafdf24 856 n1 = backing_read1(bs->backing_hd, acb->sector_num,
ce1a14dc 857 acb->buf, acb->n);
a9465922 858 if (n1 > 0) {
5fafdf24 859 acb->hd_aiocb = bdrv_aio_read(bs->backing_hd, acb->sector_num,
ce1a14dc
PB		 860 acb->buf, acb->n, qcow_aio_read_cb, acb);
861 if (acb->hd_aiocb == NULL)
a9465922
FB		 862 goto fail;
863 } else {
864 goto redo;
865 }
585f8587
FB		 866 } else {
867 /* Note: in this case, no need to wait */
ce1a14dc 868 memset(acb->buf, 0, 512 * acb->n);
585f8587
FB		 869 goto redo;
870 }
ce1a14dc 871 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
585f8587 872 /* add AIO support for compressed blocks ? */
ce1a14dc 873 if (decompress_cluster(s, acb->cluster_offset) < 0)
585f8587 874 goto fail;
5fafdf24 875 memcpy(acb->buf,
ce1a14dc 876 s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
585f8587
FB		 877 goto redo;
878 } else {
ce1a14dc 879 if ((acb->cluster_offset & 511) != 0) {
585f8587
FB		 880 ret = -EIO;
881 goto fail;
882 }
ce1a14dc 883 acb->hd_aiocb = bdrv_aio_read(s->hd,
5fafdf24 884 (acb->cluster_offset >> 9) + index_in_cluster,
ce1a14dc
PB		 885 acb->buf, acb->n, qcow_aio_read_cb, acb);
886 if (acb->hd_aiocb == NULL)
585f8587
FB		 887 goto fail;
888 }
889}
890
ce1a14dc
PB		 891static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
892 int64_t sector_num, uint8_t *buf, int nb_sectors,
893 BlockDriverCompletionFunc *cb, void *opaque)
585f8587 894{
ce1a14dc
PB		 895 QCowAIOCB *acb;
896
897 acb = qemu_aio_get(bs, cb, opaque);
898 if (!acb)
899 return NULL;
900 acb->hd_aiocb = NULL;
901 acb->sector_num = sector_num;
902 acb->buf = buf;
903 acb->nb_sectors = nb_sectors;
904 acb->n = 0;
905 acb->cluster_offset = 0;
906 return acb;
907}
908
909static BlockDriverAIOCB *qcow_aio_read(BlockDriverState *bs,
910 int64_t sector_num, uint8_t *buf, int nb_sectors,
911 BlockDriverCompletionFunc *cb, void *opaque)
912{
913 QCowAIOCB *acb;
914
915 acb = qcow_aio_setup(bs, sector_num, buf, nb_sectors, cb, opaque);
916 if (!acb)
917 return NULL;
585f8587
FB		 918
919 qcow_aio_read_cb(acb, 0);
ce1a14dc 920 return &acb->common;
585f8587
FB		 921}
922
923static void qcow_aio_write_cb(void *opaque, int ret)
924{
ce1a14dc
PB		 925 QCowAIOCB *acb = opaque;
926 BlockDriverState *bs = acb->common.bs;
585f8587 927 BDRVQcowState *s = bs->opaque;
585f8587
FB		 928 int index_in_cluster;
929 uint64_t cluster_offset;
930 const uint8_t *src_buf;
ce1a14dc
PB		 931
932 acb->hd_aiocb = NULL;
933
585f8587
FB		 934 if (ret < 0) {
935 fail:
ce1a14dc
PB		 936 acb->common.cb(acb->common.opaque, ret);
937 qemu_aio_release(acb);
585f8587
FB		 938 return;
939 }
940
ce1a14dc
PB		 941 acb->nb_sectors -= acb->n;
942 acb->sector_num += acb->n;
943 acb->buf += acb->n * 512;
585f8587 944
ce1a14dc 945 if (acb->nb_sectors == 0) {
585f8587 946 /* request completed */
ce1a14dc
PB		 947 acb->common.cb(acb->common.opaque, 0);
948 qemu_aio_release(acb);
585f8587
FB		 949 return;
950 }
3b46e624 951
ce1a14dc
PB		 952 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
953 acb->n = s->cluster_sectors - index_in_cluster;
954 if (acb->n > acb->nb_sectors)
955 acb->n = acb->nb_sectors;
5fafdf24
TS		 956 cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
957 index_in_cluster,
ce1a14dc 958 index_in_cluster + acb->n);
585f8587
FB		 959 if (!cluster_offset || (cluster_offset & 511) != 0) {
960 ret = -EIO;
961 goto fail;
962 }
963 if (s->crypt_method) {
ce1a14dc
PB		 964 if (!acb->cluster_data) {
965 acb->cluster_data = qemu_mallocz(s->cluster_size);
966 if (!acb->cluster_data) {
585f8587
FB		 967 ret = -ENOMEM;
968 goto fail;
969 }
970 }
5fafdf24 971 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
ce1a14dc
PB		 972 acb->n, 1, &s->aes_encrypt_key);
973 src_buf = acb->cluster_data;
585f8587 974 } else {
ce1a14dc 975 src_buf = acb->buf;
585f8587 976 }
ce1a14dc 977 acb->hd_aiocb = bdrv_aio_write(s->hd,
5fafdf24
TS		 978 (cluster_offset >> 9) + index_in_cluster,
979 src_buf, acb->n,
ce1a14dc
PB		 980 qcow_aio_write_cb, acb);
981 if (acb->hd_aiocb == NULL)
585f8587
FB		 982 goto fail;
983}
984
ce1a14dc
PB		 985static BlockDriverAIOCB *qcow_aio_write(BlockDriverState *bs,
986 int64_t sector_num, const uint8_t *buf, int nb_sectors,
987 BlockDriverCompletionFunc *cb, void *opaque)
585f8587 988{
585f8587 989 BDRVQcowState *s = bs->opaque;
ce1a14dc 990 QCowAIOCB *acb;
3b46e624 991
585f8587
FB		 992 s->cluster_cache_offset = -1; /* disable compressed cache */
993
ce1a14dc
PB		 994 acb = qcow_aio_setup(bs, sector_num, (uint8_t*)buf, nb_sectors, cb, opaque);
995 if (!acb)
996 return NULL;
3b46e624 997
585f8587 998 qcow_aio_write_cb(acb, 0);
ce1a14dc 999 return &acb->common;
585f8587
FB		 1000}
1001
ce1a14dc 1002static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
585f8587 1003{
ce1a14dc
PB		 1004 QCowAIOCB *acb = (QCowAIOCB *)blockacb;
1005 if (acb->hd_aiocb)
1006 bdrv_aio_cancel(acb->hd_aiocb);
1007 qemu_aio_release(acb);
585f8587
FB		 1008}
1009
1010static void qcow_close(BlockDriverState *bs)
1011{
1012 BDRVQcowState *s = bs->opaque;
1013 qemu_free(s->l1_table);
1014 qemu_free(s->l2_cache);
1015 qemu_free(s->cluster_cache);
1016 qemu_free(s->cluster_data);
1017 refcount_close(bs);
1018 bdrv_delete(s->hd);
1019}
1020
1021/* XXX: use std qcow open function ? */
1022typedef struct QCowCreateState {
1023 int cluster_size;
1024 int cluster_bits;
1025 uint16_t *refcount_block;
1026 uint64_t *refcount_table;
1027 int64_t l1_table_offset;
1028 int64_t refcount_table_offset;
1029 int64_t refcount_block_offset;
1030} QCowCreateState;
1031
1032static void create_refcount_update(QCowCreateState *s,
1033 int64_t offset, int64_t size)
1034{
1035 int refcount;
1036 int64_t start, last, cluster_offset;
1037 uint16_t *p;
1038
1039 start = offset & ~(s->cluster_size - 1);
1040 last = (offset + size - 1) & ~(s->cluster_size - 1);
5fafdf24 1041 for(cluster_offset = start; cluster_offset <= last;
585f8587
FB		 1042 cluster_offset += s->cluster_size) {
1043 p = &s->refcount_block[cluster_offset >> s->cluster_bits];
1044 refcount = be16_to_cpu(*p);
1045 refcount++;
1046 *p = cpu_to_be16(refcount);
1047 }
1048}
1049
1050static int qcow_create(const char *filename, int64_t total_size,
1051 const char *backing_file, int flags)
1052{
1053 int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
1054 QCowHeader header;
1055 uint64_t tmp, offset;
1056 QCowCreateState s1, *s = &s1;
3b46e624 1057
585f8587
FB		 1058 memset(s, 0, sizeof(*s));
1059
1060 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
1061 if (fd < 0)
1062 return -1;
1063 memset(&header, 0, sizeof(header));
1064 header.magic = cpu_to_be32(QCOW_MAGIC);
1065 header.version = cpu_to_be32(QCOW_VERSION);
1066 header.size = cpu_to_be64(total_size * 512);
1067 header_size = sizeof(header);
1068 backing_filename_len = 0;
1069 if (backing_file) {
1070 header.backing_file_offset = cpu_to_be64(header_size);
1071 backing_filename_len = strlen(backing_file);
1072 header.backing_file_size = cpu_to_be32(backing_filename_len);
1073 header_size += backing_filename_len;
1074 }
1075 s->cluster_bits = 12; /* 4 KB clusters */
1076 s->cluster_size = 1 << s->cluster_bits;
1077 header.cluster_bits = cpu_to_be32(s->cluster_bits);
1078 header_size = (header_size + 7) & ~7;
ec36ba14 1079 if (flags & BLOCK_FLAG_ENCRYPT) {
585f8587
FB		 1080 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
1081 } else {
1082 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
1083 }
1084 l2_bits = s->cluster_bits - 3;
1085 shift = s->cluster_bits + l2_bits;
1086 l1_size = (((total_size * 512) + (1LL << shift) - 1) >> shift);
1087 offset = align_offset(header_size, s->cluster_size);
1088 s->l1_table_offset = offset;
1089 header.l1_table_offset = cpu_to_be64(s->l1_table_offset);
1090 header.l1_size = cpu_to_be32(l1_size);
15e6690a 1091 offset += align_offset(l1_size * sizeof(uint64_t), s->cluster_size);
585f8587
FB		 1092
1093 s->refcount_table = qemu_mallocz(s->cluster_size);
1094 if (!s->refcount_table)
1095 goto fail;
1096 s->refcount_block = qemu_mallocz(s->cluster_size);
1097 if (!s->refcount_block)
1098 goto fail;
3b46e624 1099
585f8587
FB		 1100 s->refcount_table_offset = offset;
1101 header.refcount_table_offset = cpu_to_be64(offset);
1102 header.refcount_table_clusters = cpu_to_be32(1);
1103 offset += s->cluster_size;
1104
1105 s->refcount_table[0] = cpu_to_be64(offset);
1106 s->refcount_block_offset = offset;
1107 offset += s->cluster_size;
1108
1109 /* update refcounts */
1110 create_refcount_update(s, 0, header_size);
15e6690a 1111 create_refcount_update(s, s->l1_table_offset, l1_size * sizeof(uint64_t));
585f8587
FB		 1112 create_refcount_update(s, s->refcount_table_offset, s->cluster_size);
1113 create_refcount_update(s, s->refcount_block_offset, s->cluster_size);
3b46e624 1114
585f8587
FB		 1115 /* write all the data */
1116 write(fd, &header, sizeof(header));
1117 if (backing_file) {
1118 write(fd, backing_file, backing_filename_len);
1119 }
1120 lseek(fd, s->l1_table_offset, SEEK_SET);
1121 tmp = 0;
1122 for(i = 0;i < l1_size; i++) {
1123 write(fd, &tmp, sizeof(tmp));
1124 }
1125 lseek(fd, s->refcount_table_offset, SEEK_SET);
1126 write(fd, s->refcount_table, s->cluster_size);
3b46e624 1127
585f8587
FB		 1128 lseek(fd, s->refcount_block_offset, SEEK_SET);
1129 write(fd, s->refcount_block, s->cluster_size);
1130
1131 qemu_free(s->refcount_table);
1132 qemu_free(s->refcount_block);
1133 close(fd);
1134 return 0;
1135 fail:
1136 qemu_free(s->refcount_table);
1137 qemu_free(s->refcount_block);
1138 close(fd);
1139 return -ENOMEM;
1140}
1141
1142static int qcow_make_empty(BlockDriverState *bs)
1143{
1144#if 0
1145 /* XXX: not correct */
1146 BDRVQcowState *s = bs->opaque;
1147 uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1148 int ret;
1149
1150 memset(s->l1_table, 0, l1_length);
1151 if (bdrv_pwrite(s->hd, s->l1_table_offset, s->l1_table, l1_length) < 0)
1152 return -1;
1153 ret = bdrv_truncate(s->hd, s->l1_table_offset + l1_length);
1154 if (ret < 0)
1155 return ret;
3b46e624 1156
585f8587
FB		 1157 l2_cache_reset(bs);
1158#endif
1159 return 0;
1160}
1161
1162/* XXX: put compressed sectors first, then all the cluster aligned
1163 tables to avoid losing bytes in alignment */
5fafdf24 1164static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
585f8587
FB		 1165 const uint8_t *buf, int nb_sectors)
1166{
1167 BDRVQcowState *s = bs->opaque;
1168 z_stream strm;
1169 int ret, out_len;
1170 uint8_t *out_buf;
1171 uint64_t cluster_offset;
1172
1173 if (nb_sectors == 0) {
1174 /* align end of file to a sector boundary to ease reading with
1175 sector based I/Os */
1176 cluster_offset = bdrv_getlength(s->hd);
1177 cluster_offset = (cluster_offset + 511) & ~511;
1178 bdrv_truncate(s->hd, cluster_offset);
1179 return 0;
1180 }
1181
1182 if (nb_sectors != s->cluster_sectors)
1183 return -EINVAL;
1184
1185 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
1186 if (!out_buf)
1187 return -ENOMEM;
1188
1189 /* best compression, small window, no zlib header */
1190 memset(&strm, 0, sizeof(strm));
1191 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
5fafdf24 1192 Z_DEFLATED, -12,
585f8587
FB		 1193 9, Z_DEFAULT_STRATEGY);
1194 if (ret != 0) {
1195 qemu_free(out_buf);
1196 return -1;
1197 }
1198
1199 strm.avail_in = s->cluster_size;
1200 strm.next_in = (uint8_t *)buf;
1201 strm.avail_out = s->cluster_size;
1202 strm.next_out = out_buf;
1203
1204 ret = deflate(&strm, Z_FINISH);
1205 if (ret != Z_STREAM_END && ret != Z_OK) {
1206 qemu_free(out_buf);
1207 deflateEnd(&strm);
1208 return -1;
1209 }
1210 out_len = strm.next_out - out_buf;
1211
1212 deflateEnd(&strm);
1213
1214 if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1215 /* could not compress: write normal cluster */
1216 qcow_write(bs, sector_num, buf, s->cluster_sectors);
1217 } else {
5fafdf24 1218 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
585f8587
FB		 1219 out_len, 0, 0);
1220 cluster_offset &= s->cluster_offset_mask;
1221 if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
1222 qemu_free(out_buf);
1223 return -1;
1224 }
1225 }
3b46e624 1226
585f8587
FB		 1227 qemu_free(out_buf);
1228 return 0;
1229}
1230
1231static void qcow_flush(BlockDriverState *bs)
1232{
1233 BDRVQcowState *s = bs->opaque;
1234 bdrv_flush(s->hd);
1235}
1236
1237static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1238{
1239 BDRVQcowState *s = bs->opaque;
1240 bdi->cluster_size = s->cluster_size;
5fafdf24 1241 bdi->vm_state_offset = (int64_t)s->l1_vm_state_index <<
585f8587
FB		 1242 (s->cluster_bits + s->l2_bits);
1243 return 0;
1244}
1245
1246/*********************************************************/
1247/* snapshot support */
1248
1249/* update the refcounts of snapshots and the copied flag */
5fafdf24 1250static int update_snapshot_refcount(BlockDriverState *bs,
585f8587
FB		 1251 int64_t l1_table_offset,
1252 int l1_size,
1253 int addend)
1254{
1255 BDRVQcowState *s = bs->opaque;
1256 uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
1257 int64_t old_offset, old_l2_offset;
1258 int l2_size, i, j, l1_modified, l2_modified, nb_csectors, refcount;
3b46e624 1259
585f8587
FB		 1260 l2_cache_reset(bs);
1261
1262 l2_table = NULL;
1263 l1_table = NULL;
1264 l1_size2 = l1_size * sizeof(uint64_t);
1265 l1_allocated = 0;
1266 if (l1_table_offset != s->l1_table_offset) {
1267 l1_table = qemu_malloc(l1_size2);
1268 if (!l1_table)
1269 goto fail;
1270 l1_allocated = 1;
5fafdf24 1271 if (bdrv_pread(s->hd, l1_table_offset,
585f8587
FB		 1272 l1_table, l1_size2) != l1_size2)
1273 goto fail;
1274 for(i = 0;i < l1_size; i++)
1275 be64_to_cpus(&l1_table[i]);
1276 } else {
1277 assert(l1_size == s->l1_size);
1278 l1_table = s->l1_table;
1279 l1_allocated = 0;
1280 }
3b46e624 1281
585f8587
FB		 1282 l2_size = s->l2_size * sizeof(uint64_t);
1283 l2_table = qemu_malloc(l2_size);
1284 if (!l2_table)
1285 goto fail;
1286 l1_modified = 0;
1287 for(i = 0; i < l1_size; i++) {
1288 l2_offset = l1_table[i];
1289 if (l2_offset) {
1290 old_l2_offset = l2_offset;
1291 l2_offset &= ~QCOW_OFLAG_COPIED;
1292 l2_modified = 0;
1293 if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
1294 goto fail;
1295 for(j = 0; j < s->l2_size; j++) {
1296 offset = be64_to_cpu(l2_table[j]);
1297 if (offset != 0) {
1298 old_offset = offset;
1299 offset &= ~QCOW_OFLAG_COPIED;
1300 if (offset & QCOW_OFLAG_COMPRESSED) {
5fafdf24 1301 nb_csectors = ((offset >> s->csize_shift) &
585f8587
FB		 1302 s->csize_mask) + 1;
1303 if (addend != 0)
1304 update_refcount(bs, (offset & s->cluster_offset_mask) & ~511,
1305 nb_csectors * 512, addend);
1306 /* compressed clusters are never modified */
5fafdf24 1307 refcount = 2;
585f8587
FB		 1308 } else {
1309 if (addend != 0) {
1310 refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend);
1311 } else {
1312 refcount = get_refcount(bs, offset >> s->cluster_bits);
1313 }
1314 }
1315
1316 if (refcount == 1) {
1317 offset |= QCOW_OFLAG_COPIED;
1318 }
1319 if (offset != old_offset) {
1320 l2_table[j] = cpu_to_be64(offset);
1321 l2_modified = 1;
1322 }
1323 }
1324 }
1325 if (l2_modified) {
5fafdf24 1326 if (bdrv_pwrite(s->hd,
585f8587
FB		 1327 l2_offset, l2_table, l2_size) != l2_size)
1328 goto fail;
1329 }
1330
1331 if (addend != 0) {
1332 refcount = update_cluster_refcount(bs, l2_offset >> s->cluster_bits, addend);
1333 } else {
1334 refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
1335 }
1336 if (refcount == 1) {
1337 l2_offset |= QCOW_OFLAG_COPIED;
1338 }
1339 if (l2_offset != old_l2_offset) {
1340 l1_table[i] = l2_offset;
1341 l1_modified = 1;
1342 }
1343 }
1344 }
1345 if (l1_modified) {
1346 for(i = 0; i < l1_size; i++)
1347 cpu_to_be64s(&l1_table[i]);
5fafdf24 1348 if (bdrv_pwrite(s->hd, l1_table_offset, l1_table,
585f8587
FB		 1349 l1_size2) != l1_size2)
1350 goto fail;
1351 for(i = 0; i < l1_size; i++)
1352 be64_to_cpus(&l1_table[i]);
1353 }
1354 if (l1_allocated)
1355 qemu_free(l1_table);
1356 qemu_free(l2_table);
1357 return 0;
1358 fail:
1359 if (l1_allocated)
1360 qemu_free(l1_table);
1361 qemu_free(l2_table);
1362 return -EIO;
1363}
1364
1365static void qcow_free_snapshots(BlockDriverState *bs)
1366{
1367 BDRVQcowState *s = bs->opaque;
1368 int i;
1369
1370 for(i = 0; i < s->nb_snapshots; i++) {
1371 qemu_free(s->snapshots[i].name);
1372 qemu_free(s->snapshots[i].id_str);
1373 }
1374 qemu_free(s->snapshots);
1375 s->snapshots = NULL;
1376 s->nb_snapshots = 0;
1377}
1378
1379static int qcow_read_snapshots(BlockDriverState *bs)
1380{
1381 BDRVQcowState *s = bs->opaque;
1382 QCowSnapshotHeader h;
1383 QCowSnapshot *sn;
1384 int i, id_str_size, name_size;
1385 int64_t offset;
1386 uint32_t extra_data_size;
1387
1388 offset = s->snapshots_offset;
1389 s->snapshots = qemu_mallocz(s->nb_snapshots * sizeof(QCowSnapshot));
1390 if (!s->snapshots)
1391 goto fail;
1392 for(i = 0; i < s->nb_snapshots; i++) {
1393 offset = align_offset(offset, 8);
1394 if (bdrv_pread(s->hd, offset, &h, sizeof(h)) != sizeof(h))
1395 goto fail;
1396 offset += sizeof(h);
1397 sn = s->snapshots + i;
1398 sn->l1_table_offset = be64_to_cpu(h.l1_table_offset);
1399 sn->l1_size = be32_to_cpu(h.l1_size);
1400 sn->vm_state_size = be32_to_cpu(h.vm_state_size);
1401 sn->date_sec = be32_to_cpu(h.date_sec);
1402 sn->date_nsec = be32_to_cpu(h.date_nsec);
1403 sn->vm_clock_nsec = be64_to_cpu(h.vm_clock_nsec);
1404 extra_data_size = be32_to_cpu(h.extra_data_size);
1405
1406 id_str_size = be16_to_cpu(h.id_str_size);
1407 name_size = be16_to_cpu(h.name_size);
1408
1409 offset += extra_data_size;
1410
1411 sn->id_str = qemu_malloc(id_str_size + 1);
1412 if (!sn->id_str)
1413 goto fail;
1414 if (bdrv_pread(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
1415 goto fail;
1416 offset += id_str_size;
1417 sn->id_str[id_str_size] = '\0';
1418
1419 sn->name = qemu_malloc(name_size + 1);
1420 if (!sn->name)
1421 goto fail;
1422 if (bdrv_pread(s->hd, offset, sn->name, name_size) != name_size)
1423 goto fail;
1424 offset += name_size;
1425 sn->name[name_size] = '\0';
1426 }
1427 s->snapshots_size = offset - s->snapshots_offset;
1428 return 0;
1429 fail:
1430 qcow_free_snapshots(bs);
1431 return -1;
1432}
1433
1434/* add at the end of the file a new list of snapshots */
1435static int qcow_write_snapshots(BlockDriverState *bs)
1436{
1437 BDRVQcowState *s = bs->opaque;
1438 QCowSnapshot *sn;
1439 QCowSnapshotHeader h;
1440 int i, name_size, id_str_size, snapshots_size;
1441 uint64_t data64;
1442 uint32_t data32;
1443 int64_t offset, snapshots_offset;
1444
1445 /* compute the size of the snapshots */
1446 offset = 0;
1447 for(i = 0; i < s->nb_snapshots; i++) {
1448 sn = s->snapshots + i;
1449 offset = align_offset(offset, 8);
1450 offset += sizeof(h);
1451 offset += strlen(sn->id_str);
1452 offset += strlen(sn->name);
1453 }
1454 snapshots_size = offset;
1455
1456 snapshots_offset = alloc_clusters(bs, snapshots_size);
1457 offset = snapshots_offset;
3b46e624 1458
585f8587
FB		 1459 for(i = 0; i < s->nb_snapshots; i++) {
1460 sn = s->snapshots + i;
1461 memset(&h, 0, sizeof(h));
1462 h.l1_table_offset = cpu_to_be64(sn->l1_table_offset);
1463 h.l1_size = cpu_to_be32(sn->l1_size);
1464 h.vm_state_size = cpu_to_be32(sn->vm_state_size);
1465 h.date_sec = cpu_to_be32(sn->date_sec);
1466 h.date_nsec = cpu_to_be32(sn->date_nsec);
1467 h.vm_clock_nsec = cpu_to_be64(sn->vm_clock_nsec);
3b46e624 1468
585f8587
FB		 1469 id_str_size = strlen(sn->id_str);
1470 name_size = strlen(sn->name);
1471 h.id_str_size = cpu_to_be16(id_str_size);
1472 h.name_size = cpu_to_be16(name_size);
1473 offset = align_offset(offset, 8);
1474 if (bdrv_pwrite(s->hd, offset, &h, sizeof(h)) != sizeof(h))
1475 goto fail;
1476 offset += sizeof(h);
1477 if (bdrv_pwrite(s->hd, offset, sn->id_str, id_str_size) != id_str_size)
1478 goto fail;
1479 offset += id_str_size;
1480 if (bdrv_pwrite(s->hd, offset, sn->name, name_size) != name_size)
1481 goto fail;
1482 offset += name_size;
1483 }
1484
1485 /* update the various header fields */
1486 data64 = cpu_to_be64(snapshots_offset);
1487 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, snapshots_offset),
1488 &data64, sizeof(data64)) != sizeof(data64))
1489 goto fail;
1490 data32 = cpu_to_be32(s->nb_snapshots);
1491 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, nb_snapshots),
1492 &data32, sizeof(data32)) != sizeof(data32))
1493 goto fail;
1494
1495 /* free the old snapshot table */
1496 free_clusters(bs, s->snapshots_offset, s->snapshots_size);
1497 s->snapshots_offset = snapshots_offset;
1498 s->snapshots_size = snapshots_size;
1499 return 0;
1500 fail:
1501 return -1;
1502}
1503
1504static void find_new_snapshot_id(BlockDriverState *bs,
1505 char *id_str, int id_str_size)
1506{
1507 BDRVQcowState *s = bs->opaque;
1508 QCowSnapshot *sn;
1509 int i, id, id_max = 0;
1510
1511 for(i = 0; i < s->nb_snapshots; i++) {
1512 sn = s->snapshots + i;
1513 id = strtoul(sn->id_str, NULL, 10);
1514 if (id > id_max)
1515 id_max = id;
1516 }
1517 snprintf(id_str, id_str_size, "%d", id_max + 1);
1518}
1519
1520static int find_snapshot_by_id(BlockDriverState *bs, const char *id_str)
1521{
1522 BDRVQcowState *s = bs->opaque;
1523 int i;
1524
1525 for(i = 0; i < s->nb_snapshots; i++) {
1526 if (!strcmp(s->snapshots[i].id_str, id_str))
1527 return i;
1528 }
1529 return -1;
1530}
1531
1532static int find_snapshot_by_id_or_name(BlockDriverState *bs, const char *name)
1533{
1534 BDRVQcowState *s = bs->opaque;
1535 int i, ret;
3b46e624 1536
585f8587
FB		 1537 ret = find_snapshot_by_id(bs, name);
1538 if (ret >= 0)
1539 return ret;
1540 for(i = 0; i < s->nb_snapshots; i++) {
1541 if (!strcmp(s->snapshots[i].name, name))
1542 return i;
1543 }
1544 return -1;
1545}
1546
1547/* if no id is provided, a new one is constructed */
5fafdf24 1548static int qcow_snapshot_create(BlockDriverState *bs,
585f8587
FB		 1549 QEMUSnapshotInfo *sn_info)
1550{
1551 BDRVQcowState *s = bs->opaque;
1552 QCowSnapshot *snapshots1, sn1, *sn = &sn1;
1553 int i, ret;
1554 uint64_t *l1_table = NULL;
3b46e624 1555
585f8587
FB		 1556 memset(sn, 0, sizeof(*sn));
1557
1558 if (sn_info->id_str[0] == '\0') {
1559 /* compute a new id */
1560 find_new_snapshot_id(bs, sn_info->id_str, sizeof(sn_info->id_str));
1561 }
1562
1563 /* check that the ID is unique */
1564 if (find_snapshot_by_id(bs, sn_info->id_str) >= 0)
1565 return -ENOENT;
1566
1567 sn->id_str = qemu_strdup(sn_info->id_str);
1568 if (!sn->id_str)
1569 goto fail;
1570 sn->name = qemu_strdup(sn_info->name);
1571 if (!sn->name)
1572 goto fail;
1573 sn->vm_state_size = sn_info->vm_state_size;
1574 sn->date_sec = sn_info->date_sec;
1575 sn->date_nsec = sn_info->date_nsec;
1576 sn->vm_clock_nsec = sn_info->vm_clock_nsec;
1577
1578 ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1);
1579 if (ret < 0)
1580 goto fail;
1581
1582 /* create the L1 table of the snapshot */
1583 sn->l1_table_offset = alloc_clusters(bs, s->l1_size * sizeof(uint64_t));
1584 sn->l1_size = s->l1_size;
1585
1586 l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t));
1587 if (!l1_table)
1588 goto fail;
1589 for(i = 0; i < s->l1_size; i++) {
1590 l1_table[i] = cpu_to_be64(s->l1_table[i]);
1591 }
1592 if (bdrv_pwrite(s->hd, sn->l1_table_offset,
5fafdf24 1593 l1_table, s->l1_size * sizeof(uint64_t)) !=
585f8587
FB		 1594 (s->l1_size * sizeof(uint64_t)))
1595 goto fail;
1596 qemu_free(l1_table);
1597 l1_table = NULL;
1598
1599 snapshots1 = qemu_malloc((s->nb_snapshots + 1) * sizeof(QCowSnapshot));
1600 if (!snapshots1)
1601 goto fail;
1602 memcpy(snapshots1, s->snapshots, s->nb_snapshots * sizeof(QCowSnapshot));
1603 s->snapshots = snapshots1;
1604 s->snapshots[s->nb_snapshots++] = *sn;
1605
1606 if (qcow_write_snapshots(bs) < 0)
1607 goto fail;
1608#ifdef DEBUG_ALLOC
1609 check_refcounts(bs);
1610#endif
1611 return 0;
1612 fail:
1613 qemu_free(sn->name);
1614 qemu_free(l1_table);
1615 return -1;
1616}
1617
1618/* copy the snapshot 'snapshot_name' into the current disk image */
5fafdf24 1619static int qcow_snapshot_goto(BlockDriverState *bs,
585f8587
FB		 1620 const char *snapshot_id)
1621{
1622 BDRVQcowState *s = bs->opaque;
1623 QCowSnapshot *sn;
1624 int i, snapshot_index, l1_size2;
1625
1626 snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
1627 if (snapshot_index < 0)
1628 return -ENOENT;
1629 sn = &s->snapshots[snapshot_index];
1630
1631 if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, -1) < 0)
1632 goto fail;
1633
1634 if (grow_l1_table(bs, sn->l1_size) < 0)
1635 goto fail;
1636
1637 s->l1_size = sn->l1_size;
1638 l1_size2 = s->l1_size * sizeof(uint64_t);
1639 /* copy the snapshot l1 table to the current l1 table */
5fafdf24 1640 if (bdrv_pread(s->hd, sn->l1_table_offset,
585f8587
FB		 1641 s->l1_table, l1_size2) != l1_size2)
1642 goto fail;
1643 if (bdrv_pwrite(s->hd, s->l1_table_offset,
1644 s->l1_table, l1_size2) != l1_size2)
1645 goto fail;
1646 for(i = 0;i < s->l1_size; i++) {
1647 be64_to_cpus(&s->l1_table[i]);
1648 }
1649
1650 if (update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 1) < 0)
1651 goto fail;
1652
1653#ifdef DEBUG_ALLOC
1654 check_refcounts(bs);
1655#endif
1656 return 0;
1657 fail:
1658 return -EIO;
1659}
1660
1661static int qcow_snapshot_delete(BlockDriverState *bs, const char *snapshot_id)
1662{
1663 BDRVQcowState *s = bs->opaque;
1664 QCowSnapshot *sn;
1665 int snapshot_index, ret;
3b46e624 1666
585f8587
FB		 1667 snapshot_index = find_snapshot_by_id_or_name(bs, snapshot_id);
1668 if (snapshot_index < 0)
1669 return -ENOENT;
1670 sn = &s->snapshots[snapshot_index];
1671
1672 ret = update_snapshot_refcount(bs, sn->l1_table_offset, sn->l1_size, -1);
1673 if (ret < 0)
1674 return ret;
1675 /* must update the copied flag on the current cluster offsets */
1676 ret = update_snapshot_refcount(bs, s->l1_table_offset, s->l1_size, 0);
1677 if (ret < 0)
1678 return ret;
1679 free_clusters(bs, sn->l1_table_offset, sn->l1_size * sizeof(uint64_t));
1680
1681 qemu_free(sn->id_str);
1682 qemu_free(sn->name);
1683 memmove(sn, sn + 1, (s->nb_snapshots - snapshot_index - 1) * sizeof(*sn));
1684 s->nb_snapshots--;
1685 ret = qcow_write_snapshots(bs);
1686 if (ret < 0) {
1687 /* XXX: restore snapshot if error ? */
1688 return ret;
1689 }
1690#ifdef DEBUG_ALLOC
1691 check_refcounts(bs);
1692#endif
1693 return 0;
1694}
1695
5fafdf24 1696static int qcow_snapshot_list(BlockDriverState *bs,
585f8587
FB		 1697 QEMUSnapshotInfo **psn_tab)
1698{
1699 BDRVQcowState *s = bs->opaque;
1700 QEMUSnapshotInfo *sn_tab, *sn_info;
1701 QCowSnapshot *sn;
1702 int i;
1703
1704 sn_tab = qemu_mallocz(s->nb_snapshots * sizeof(QEMUSnapshotInfo));
1705 if (!sn_tab)
1706 goto fail;
1707 for(i = 0; i < s->nb_snapshots; i++) {
1708 sn_info = sn_tab + i;
1709 sn = s->snapshots + i;
1710 pstrcpy(sn_info->id_str, sizeof(sn_info->id_str),
1711 sn->id_str);
1712 pstrcpy(sn_info->name, sizeof(sn_info->name),
1713 sn->name);
1714 sn_info->vm_state_size = sn->vm_state_size;
1715 sn_info->date_sec = sn->date_sec;
1716 sn_info->date_nsec = sn->date_nsec;
1717 sn_info->vm_clock_nsec = sn->vm_clock_nsec;
1718 }
1719 *psn_tab = sn_tab;
1720 return s->nb_snapshots;
1721 fail:
1722 qemu_free(sn_tab);
1723 *psn_tab = NULL;
1724 return -ENOMEM;
1725}
1726
1727/*********************************************************/
1728/* refcount handling */
1729
1730static int refcount_init(BlockDriverState *bs)
1731{
1732 BDRVQcowState *s = bs->opaque;
1733 int ret, refcount_table_size2, i;
3b46e624 1734
585f8587
FB		 1735 s->refcount_block_cache = qemu_malloc(s->cluster_size);
1736 if (!s->refcount_block_cache)
1737 goto fail;
1738 refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
1739 s->refcount_table = qemu_malloc(refcount_table_size2);
1740 if (!s->refcount_table)
1741 goto fail;
1742 if (s->refcount_table_size > 0) {
1743 ret = bdrv_pread(s->hd, s->refcount_table_offset,
1744 s->refcount_table, refcount_table_size2);
1745 if (ret != refcount_table_size2)
1746 goto fail;
1747 for(i = 0; i < s->refcount_table_size; i++)
1748 be64_to_cpus(&s->refcount_table[i]);
1749 }
1750 return 0;
1751 fail:
1752 return -ENOMEM;
1753}
1754
1755static void refcount_close(BlockDriverState *bs)
1756{
1757 BDRVQcowState *s = bs->opaque;
1758 qemu_free(s->refcount_block_cache);
1759 qemu_free(s->refcount_table);
1760}
1761
1762
5fafdf24 1763static int load_refcount_block(BlockDriverState *bs,
585f8587
FB		 1764 int64_t refcount_block_offset)
1765{
1766 BDRVQcowState *s = bs->opaque;
1767 int ret;
5fafdf24 1768 ret = bdrv_pread(s->hd, refcount_block_offset, s->refcount_block_cache,
585f8587
FB		 1769 s->cluster_size);
1770 if (ret != s->cluster_size)
1771 return -EIO;
1772 s->refcount_block_cache_offset = refcount_block_offset;
1773 return 0;
1774}
1775
1776static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
1777{
1778 BDRVQcowState *s = bs->opaque;
1779 int refcount_table_index, block_index;
1780 int64_t refcount_block_offset;
1781
1782 refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
1783 if (refcount_table_index >= s->refcount_table_size)
1784 return 0;
1785 refcount_block_offset = s->refcount_table[refcount_table_index];
1786 if (!refcount_block_offset)
1787 return 0;
1788 if (refcount_block_offset != s->refcount_block_cache_offset) {
1789 /* better than nothing: return allocated if read error */
1790 if (load_refcount_block(bs, refcount_block_offset) < 0)
1791 return 1;
1792 }
5fafdf24 1793 block_index = cluster_index &
585f8587
FB		 1794 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
1795 return be16_to_cpu(s->refcount_block_cache[block_index]);
1796}
1797
1798/* return < 0 if error */
1799static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size)
1800{
1801 BDRVQcowState *s = bs->opaque;
1802 int i, nb_clusters;
1803
1804 nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
1805 for(;;) {
1806 if (get_refcount(bs, s->free_cluster_index) == 0) {
1807 s->free_cluster_index++;
1808 for(i = 1; i < nb_clusters; i++) {
1809 if (get_refcount(bs, s->free_cluster_index) != 0)
1810 goto not_found;
1811 s->free_cluster_index++;
1812 }
1813#ifdef DEBUG_ALLOC2
1814 printf("alloc_clusters: size=%lld -> %lld\n",
5fafdf24 1815 size,
585f8587
FB		 1816 (s->free_cluster_index - nb_clusters) << s->cluster_bits);
1817#endif
1818 return (s->free_cluster_index - nb_clusters) << s->cluster_bits;
1819 } else {
1820 not_found:
1821 s->free_cluster_index++;
1822 }
1823 }
1824}
1825
1826static int64_t alloc_clusters(BlockDriverState *bs, int64_t size)
1827{
1828 int64_t offset;
1829
1830 offset = alloc_clusters_noref(bs, size);
1831 update_refcount(bs, offset, size, 1);
1832 return offset;
1833}
1834
1835/* only used to allocate compressed sectors. We try to allocate
1836 contiguous sectors. size must be <= cluster_size */
1837static int64_t alloc_bytes(BlockDriverState *bs, int size)
1838{
1839 BDRVQcowState *s = bs->opaque;
1840 int64_t offset, cluster_offset;
1841 int free_in_cluster;
3b46e624 1842
585f8587
FB		 1843 assert(size > 0 && size <= s->cluster_size);
1844 if (s->free_byte_offset == 0) {
1845 s->free_byte_offset = alloc_clusters(bs, s->cluster_size);
1846 }
1847 redo:
5fafdf24 1848 free_in_cluster = s->cluster_size -
585f8587
FB		 1849 (s->free_byte_offset & (s->cluster_size - 1));
1850 if (size <= free_in_cluster) {
1851 /* enough space in current cluster */
1852 offset = s->free_byte_offset;
1853 s->free_byte_offset += size;
1854 free_in_cluster -= size;
1855 if (free_in_cluster == 0)
1856 s->free_byte_offset = 0;
1857 if ((offset & (s->cluster_size - 1)) != 0)
1858 update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
1859 } else {
1860 offset = alloc_clusters(bs, s->cluster_size);
1861 cluster_offset = s->free_byte_offset & ~(s->cluster_size - 1);
1862 if ((cluster_offset + s->cluster_size) == offset) {
1863 /* we are lucky: contiguous data */
1864 offset = s->free_byte_offset;
1865 update_cluster_refcount(bs, offset >> s->cluster_bits, 1);
1866 s->free_byte_offset += size;
1867 } else {
1868 s->free_byte_offset = offset;
1869 goto redo;
1870 }
1871 }
1872 return offset;
1873}
1874
5fafdf24 1875static void free_clusters(BlockDriverState *bs,
585f8587
FB		 1876 int64_t offset, int64_t size)
1877{
1878 update_refcount(bs, offset, size, -1);
1879}
1880
1881static int grow_refcount_table(BlockDriverState *bs, int min_size)
1882{
1883 BDRVQcowState *s = bs->opaque;
1884 int new_table_size, new_table_size2, refcount_table_clusters, i, ret;
1885 uint64_t *new_table;
1886 int64_t table_offset;
1887 uint64_t data64;
1888 uint32_t data32;
23be50f1
TS		 1889 int old_table_size;
1890 int64_t old_table_offset;
585f8587
FB		 1891
1892 if (min_size <= s->refcount_table_size)
1893 return 0;
1894 /* compute new table size */
1895 refcount_table_clusters = s->refcount_table_size >> (s->cluster_bits - 3);
1896 for(;;) {
1897 if (refcount_table_clusters == 0) {
1898 refcount_table_clusters = 1;
1899 } else {
1900 refcount_table_clusters = (refcount_table_clusters * 3 + 1) / 2;
1901 }
1902 new_table_size = refcount_table_clusters << (s->cluster_bits - 3);
1903 if (min_size <= new_table_size)
1904 break;
1905 }
15e6690a
FB		 1906#ifdef DEBUG_ALLOC2
1907 printf("grow_refcount_table from %d to %d\n",
1908 s->refcount_table_size,
1909 new_table_size);
1910#endif
585f8587
FB		 1911 new_table_size2 = new_table_size * sizeof(uint64_t);
1912 new_table = qemu_mallocz(new_table_size2);
1913 if (!new_table)
1914 return -ENOMEM;
5fafdf24 1915 memcpy(new_table, s->refcount_table,
585f8587
FB		 1916 s->refcount_table_size * sizeof(uint64_t));
1917 for(i = 0; i < s->refcount_table_size; i++)
1918 cpu_to_be64s(&new_table[i]);
1919 /* Note: we cannot update the refcount now to avoid recursion */
1920 table_offset = alloc_clusters_noref(bs, new_table_size2);
1921 ret = bdrv_pwrite(s->hd, table_offset, new_table, new_table_size2);
5fafdf24 1922 if (ret != new_table_size2)
585f8587
FB		 1923 goto fail;
1924 for(i = 0; i < s->refcount_table_size; i++)
1925 be64_to_cpus(&new_table[i]);
1926
1927 data64 = cpu_to_be64(table_offset);
1928 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_offset),
1929 &data64, sizeof(data64)) != sizeof(data64))
1930 goto fail;
1931 data32 = cpu_to_be32(refcount_table_clusters);
1932 if (bdrv_pwrite(s->hd, offsetof(QCowHeader, refcount_table_clusters),
1933 &data32, sizeof(data32)) != sizeof(data32))
1934 goto fail;
1935 qemu_free(s->refcount_table);
23be50f1
TS		 1936 old_table_offset = s->refcount_table_offset;
1937 old_table_size = s->refcount_table_size;
585f8587
FB		 1938 s->refcount_table = new_table;
1939 s->refcount_table_size = new_table_size;
a4080ece 1940 s->refcount_table_offset = table_offset;
585f8587
FB		 1941
1942 update_refcount(bs, table_offset, new_table_size2, 1);
23be50f1 1943 free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
585f8587
FB		 1944 return 0;
1945 fail:
1946 free_clusters(bs, table_offset, new_table_size2);
1947 qemu_free(new_table);
1948 return -EIO;
1949}
1950
1951/* addend must be 1 or -1 */
1952/* XXX: cache several refcount block clusters ? */
5fafdf24 1953static int update_cluster_refcount(BlockDriverState *bs,
585f8587
FB		 1954 int64_t cluster_index,
1955 int addend)
1956{
1957 BDRVQcowState *s = bs->opaque;
1958 int64_t offset, refcount_block_offset;
1959 int ret, refcount_table_index, block_index, refcount;
1960 uint64_t data64;
1961
1962 refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
1963 if (refcount_table_index >= s->refcount_table_size) {
1964 if (addend < 0)
1965 return -EINVAL;
1966 ret = grow_refcount_table(bs, refcount_table_index + 1);
1967 if (ret < 0)
1968 return ret;
1969 }
1970 refcount_block_offset = s->refcount_table[refcount_table_index];
1971 if (!refcount_block_offset) {
1972 if (addend < 0)
1973 return -EINVAL;
1974 /* create a new refcount block */
1975 /* Note: we cannot update the refcount now to avoid recursion */
1976 offset = alloc_clusters_noref(bs, s->cluster_size);
1977 memset(s->refcount_block_cache, 0, s->cluster_size);
1978 ret = bdrv_pwrite(s->hd, offset, s->refcount_block_cache, s->cluster_size);
1979 if (ret != s->cluster_size)
1980 return -EINVAL;
1981 s->refcount_table[refcount_table_index] = offset;
1982 data64 = cpu_to_be64(offset);
5fafdf24
TS		 1983 ret = bdrv_pwrite(s->hd, s->refcount_table_offset +
1984 refcount_table_index * sizeof(uint64_t),
585f8587
FB		 1985 &data64, sizeof(data64));
1986 if (ret != sizeof(data64))
1987 return -EINVAL;
1988
1989 refcount_block_offset = offset;
1990 s->refcount_block_cache_offset = offset;
1991 update_refcount(bs, offset, s->cluster_size, 1);
1992 } else {
1993 if (refcount_block_offset != s->refcount_block_cache_offset) {
1994 if (load_refcount_block(bs, refcount_block_offset) < 0)
1995 return -EIO;
1996 }
1997 }
1998 /* we can update the count and save it */
5fafdf24 1999 block_index = cluster_index &
585f8587
FB		 2000 ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
2001 refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
2002 refcount += addend;
2003 if (refcount < 0 || refcount > 0xffff)
2004 return -EINVAL;
2005 if (refcount == 0 && cluster_index < s->free_cluster_index) {
2006 s->free_cluster_index = cluster_index;
2007 }
2008 s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
5fafdf24
TS		 2009 if (bdrv_pwrite(s->hd,
2010 refcount_block_offset + (block_index << REFCOUNT_SHIFT),
585f8587
FB		 2011 &s->refcount_block_cache[block_index], 2) != 2)
2012 return -EIO;
2013 return refcount;
2014}
2015
5fafdf24
TS		 2016static void update_refcount(BlockDriverState *bs,
2017 int64_t offset, int64_t length,
585f8587
FB		 2018 int addend)
2019{
2020 BDRVQcowState *s = bs->opaque;
2021 int64_t start, last, cluster_offset;
2022
2023#ifdef DEBUG_ALLOC2
5fafdf24 2024 printf("update_refcount: offset=%lld size=%lld addend=%d\n",
585f8587
FB		 2025 offset, length, addend);
2026#endif
2027 if (length <= 0)
2028 return;
2029 start = offset & ~(s->cluster_size - 1);
2030 last = (offset + length - 1) & ~(s->cluster_size - 1);
5fafdf24 2031 for(cluster_offset = start; cluster_offset <= last;
585f8587
FB		 2032 cluster_offset += s->cluster_size) {
2033 update_cluster_refcount(bs, cluster_offset >> s->cluster_bits, addend);
2034 }
2035}
2036
2037#ifdef DEBUG_ALLOC
5fafdf24
TS		 2038static void inc_refcounts(BlockDriverState *bs,
2039 uint16_t *refcount_table,
585f8587
FB		 2040 int refcount_table_size,
2041 int64_t offset, int64_t size)
2042{
2043 BDRVQcowState *s = bs->opaque;
2044 int64_t start, last, cluster_offset;
2045 int k;
3b46e624 2046
585f8587
FB		 2047 if (size <= 0)
2048 return;
2049
2050 start = offset & ~(s->cluster_size - 1);
2051 last = (offset + size - 1) & ~(s->cluster_size - 1);
5fafdf24 2052 for(cluster_offset = start; cluster_offset <= last;
585f8587
FB		 2053 cluster_offset += s->cluster_size) {
2054 k = cluster_offset >> s->cluster_bits;
2055 if (k < 0 || k >= refcount_table_size) {
2056 printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset);
2057 } else {
2058 if (++refcount_table[k] == 0) {
2059 printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset);
2060 }
2061 }
2062 }
2063}
2064
5fafdf24
TS		 2065static int check_refcounts_l1(BlockDriverState *bs,
2066 uint16_t *refcount_table,
585f8587
FB		 2067 int refcount_table_size,
2068 int64_t l1_table_offset, int l1_size,
2069 int check_copied)
2070{
2071 BDRVQcowState *s = bs->opaque;
2072 uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
2073 int l2_size, i, j, nb_csectors, refcount;
2074
2075 l2_table = NULL;
2076 l1_size2 = l1_size * sizeof(uint64_t);
2077
2078 inc_refcounts(bs, refcount_table, refcount_table_size,
2079 l1_table_offset, l1_size2);
2080
2081 l1_table = qemu_malloc(l1_size2);
2082 if (!l1_table)
2083 goto fail;
5fafdf24 2084 if (bdrv_pread(s->hd, l1_table_offset,
585f8587
FB		 2085 l1_table, l1_size2) != l1_size2)
2086 goto fail;
2087 for(i = 0;i < l1_size; i++)
2088 be64_to_cpus(&l1_table[i]);
3b46e624 2089
585f8587
FB		 2090 l2_size = s->l2_size * sizeof(uint64_t);
2091 l2_table = qemu_malloc(l2_size);
2092 if (!l2_table)
2093 goto fail;
2094 for(i = 0; i < l1_size; i++) {
2095 l2_offset = l1_table[i];
2096 if (l2_offset) {
2097 if (check_copied) {
2098 refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
2099 if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
2100 printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
2101 l2_offset, refcount);
2102 }
2103 }
2104 l2_offset &= ~QCOW_OFLAG_COPIED;
2105 if (bdrv_pread(s->hd, l2_offset, l2_table, l2_size) != l2_size)
2106 goto fail;
2107 for(j = 0; j < s->l2_size; j++) {
2108 offset = be64_to_cpu(l2_table[j]);
2109 if (offset != 0) {
2110 if (offset & QCOW_OFLAG_COMPRESSED) {
2111 if (offset & QCOW_OFLAG_COPIED) {
2112 printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
2113 offset >> s->cluster_bits);
2114 offset &= ~QCOW_OFLAG_COPIED;
2115 }
5fafdf24 2116 nb_csectors = ((offset >> s->csize_shift) &
585f8587
FB		 2117 s->csize_mask) + 1;
2118 offset &= s->cluster_offset_mask;
5fafdf24 2119 inc_refcounts(bs, refcount_table,
585f8587
FB		 2120 refcount_table_size,
2121 offset & ~511, nb_csectors * 512);
2122 } else {
2123 if (check_copied) {
2124 refcount = get_refcount(bs, (offset & ~QCOW_OFLAG_COPIED) >> s->cluster_bits);
2125 if ((refcount == 1) != ((offset & QCOW_OFLAG_COPIED) != 0)) {
2126 printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
2127 offset, refcount);
2128 }
2129 }
2130 offset &= ~QCOW_OFLAG_COPIED;
5fafdf24 2131 inc_refcounts(bs, refcount_table,
585f8587
FB		 2132 refcount_table_size,
2133 offset, s->cluster_size);
2134 }
2135 }
2136 }
5fafdf24 2137 inc_refcounts(bs, refcount_table,
585f8587
FB		 2138 refcount_table_size,
2139 l2_offset,
2140 s->cluster_size);
2141 }
2142 }
2143 qemu_free(l1_table);
2144 qemu_free(l2_table);
2145 return 0;
2146 fail:
2147 printf("ERROR: I/O error in check_refcounts_l1\n");
2148 qemu_free(l1_table);
2149 qemu_free(l2_table);
2150 return -EIO;
2151}
2152
2153static void check_refcounts(BlockDriverState *bs)
2154{
2155 BDRVQcowState *s = bs->opaque;
2156 int64_t size;
2157 int nb_clusters, refcount1, refcount2, i;
2158 QCowSnapshot *sn;
2159 uint16_t *refcount_table;
2160
2161 size = bdrv_getlength(s->hd);
2162 nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
2163 refcount_table = qemu_mallocz(nb_clusters * sizeof(uint16_t));
15e6690a 2164
585f8587
FB		 2165 /* header */
2166 inc_refcounts(bs, refcount_table, nb_clusters,
2167 0, s->cluster_size);
3b46e624 2168
585f8587
FB		 2169 check_refcounts_l1(bs, refcount_table, nb_clusters,
2170 s->l1_table_offset, s->l1_size, 1);
2171
2172 /* snapshots */
2173 for(i = 0; i < s->nb_snapshots; i++) {
2174 sn = s->snapshots + i;
2175 check_refcounts_l1(bs, refcount_table, nb_clusters,
2176 sn->l1_table_offset, sn->l1_size, 0);
2177 }
2178 inc_refcounts(bs, refcount_table, nb_clusters,
2179 s->snapshots_offset, s->snapshots_size);
2180
2181 /* refcount data */
2182 inc_refcounts(bs, refcount_table, nb_clusters,
5fafdf24 2183 s->refcount_table_offset,
585f8587
FB		 2184 s->refcount_table_size * sizeof(uint64_t));
2185 for(i = 0; i < s->refcount_table_size; i++) {
2186 int64_t offset;
2187 offset = s->refcount_table[i];
2188 if (offset != 0) {
2189 inc_refcounts(bs, refcount_table, nb_clusters,
2190 offset, s->cluster_size);
2191 }
2192 }
2193
2194 /* compare ref counts */
2195 for(i = 0; i < nb_clusters; i++) {
2196 refcount1 = get_refcount(bs, i);
2197 refcount2 = refcount_table[i];
2198 if (refcount1 != refcount2)
2199 printf("ERROR cluster %d refcount=%d reference=%d\n",
2200 i, refcount1, refcount2);
2201 }
2202
2203 qemu_free(refcount_table);
2204}
2205
2206#if 0
2207static void dump_refcounts(BlockDriverState *bs)
2208{
2209 BDRVQcowState *s = bs->opaque;
2210 int64_t nb_clusters, k, k1, size;
2211 int refcount;
2212
2213 size = bdrv_getlength(s->hd);
2214 nb_clusters = (size + s->cluster_size - 1) >> s->cluster_bits;
2215 for(k = 0; k < nb_clusters;) {
2216 k1 = k;
2217 refcount = get_refcount(bs, k);
2218 k++;
2219 while (k < nb_clusters && get_refcount(bs, k) == refcount)
2220 k++;
2221 printf("%lld: refcount=%d nb=%lld\n", k, refcount, k - k1);
2222 }
2223}
2224#endif
2225#endif
2226
2227BlockDriver bdrv_qcow2 = {
2228 "qcow2",
2229 sizeof(BDRVQcowState),
2230 qcow_probe,
2231 qcow_open,
2232 NULL,
2233 NULL,
2234 qcow_close,
2235 qcow_create,
2236 qcow_flush,
2237 qcow_is_allocated,
2238 qcow_set_key,
2239 qcow_make_empty,
2240
585f8587
FB		 2241 .bdrv_aio_read = qcow_aio_read,
2242 .bdrv_aio_write = qcow_aio_write,
2243 .bdrv_aio_cancel = qcow_aio_cancel,
ce1a14dc 2244 .aiocb_size = sizeof(QCowAIOCB),
585f8587
FB		 2245 .bdrv_write_compressed = qcow_write_compressed,
2246
2247 .bdrv_snapshot_create = qcow_snapshot_create,
2248 .bdrv_snapshot_goto = qcow_snapshot_goto,
2249 .bdrv_snapshot_delete = qcow_snapshot_delete,
2250 .bdrv_snapshot_list = qcow_snapshot_list,
2251 .bdrv_get_info = qcow_get_info,
2252};
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