2 * Block driver for the QCOW version 2 format
4 * Copyright (c) 2004-2006 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 #include "qemu-common.h"
25 #include "block_int.h"
31 Differences with QCOW:
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
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.
47 //#define DEBUG_ALLOC2
49 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
50 #define QCOW_VERSION 2
52 #define QCOW_CRYPT_NONE 0
53 #define QCOW_CRYPT_AES 1
55 #define QCOW_MAX_CRYPT_CLUSTERS 32
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)
62 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
65 #define offsetof(type, field) ((size_t) &((type *)0)->field)
68 typedef struct QCowHeader
{
71 uint64_t backing_file_offset
;
72 uint32_t backing_file_size
;
73 uint32_t cluster_bits
;
74 uint64_t size
; /* in bytes */
75 uint32_t crypt_method
;
76 uint32_t l1_size
; /* XXX: save number of clusters instead ? */
77 uint64_t l1_table_offset
;
78 uint64_t refcount_table_offset
;
79 uint32_t refcount_table_clusters
;
80 uint32_t nb_snapshots
;
81 uint64_t snapshots_offset
;
84 typedef struct __attribute__((packed
)) QCowSnapshotHeader
{
85 /* header is 8 byte aligned */
86 uint64_t l1_table_offset
;
95 uint64_t vm_clock_nsec
;
97 uint32_t vm_state_size
;
98 uint32_t extra_data_size
; /* for extension */
99 /* extra data follows */
102 } QCowSnapshotHeader
;
104 #define L2_CACHE_SIZE 16
106 typedef struct QCowSnapshot
{
107 uint64_t l1_table_offset
;
111 uint32_t vm_state_size
;
114 uint64_t vm_clock_nsec
;
117 typedef struct BDRVQcowState
{
118 BlockDriverState
*hd
;
125 int l1_vm_state_index
;
128 uint64_t cluster_offset_mask
;
129 uint64_t l1_table_offset
;
132 uint64_t l2_cache_offsets
[L2_CACHE_SIZE
];
133 uint32_t l2_cache_counts
[L2_CACHE_SIZE
];
134 uint8_t *cluster_cache
;
135 uint8_t *cluster_data
;
136 uint64_t cluster_cache_offset
;
138 uint64_t *refcount_table
;
139 uint64_t refcount_table_offset
;
140 uint32_t refcount_table_size
;
141 uint64_t refcount_block_cache_offset
;
142 uint16_t *refcount_block_cache
;
143 int64_t free_cluster_index
;
144 int64_t free_byte_offset
;
146 uint32_t crypt_method
; /* current crypt method, 0 if no key yet */
147 uint32_t crypt_method_header
;
148 AES_KEY aes_encrypt_key
;
149 AES_KEY aes_decrypt_key
;
150 uint64_t snapshots_offset
;
153 QCowSnapshot
*snapshots
;
156 static int decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
);
157 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
158 uint8_t *buf
, int nb_sectors
);
159 static int qcow_read_snapshots(BlockDriverState
*bs
);
160 static void qcow_free_snapshots(BlockDriverState
*bs
);
161 static int refcount_init(BlockDriverState
*bs
);
162 static void refcount_close(BlockDriverState
*bs
);
163 static int get_refcount(BlockDriverState
*bs
, int64_t cluster_index
);
164 static int update_cluster_refcount(BlockDriverState
*bs
,
165 int64_t cluster_index
,
167 static void update_refcount(BlockDriverState
*bs
,
168 int64_t offset
, int64_t length
,
170 static int64_t alloc_clusters(BlockDriverState
*bs
, int64_t size
);
171 static int64_t alloc_bytes(BlockDriverState
*bs
, int size
);
172 static void free_clusters(BlockDriverState
*bs
,
173 int64_t offset
, int64_t size
);
175 static void check_refcounts(BlockDriverState
*bs
);
178 static int qcow_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
180 const QCowHeader
*cow_header
= (const void *)buf
;
182 if (buf_size
>= sizeof(QCowHeader
) &&
183 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
184 be32_to_cpu(cow_header
->version
) == QCOW_VERSION
)
190 static int qcow_open(BlockDriverState
*bs
, const char *filename
, int flags
)
192 BDRVQcowState
*s
= bs
->opaque
;
193 int len
, i
, shift
, ret
;
196 ret
= bdrv_file_open(&s
->hd
, filename
, flags
);
199 if (bdrv_pread(s
->hd
, 0, &header
, sizeof(header
)) != sizeof(header
))
201 be32_to_cpus(&header
.magic
);
202 be32_to_cpus(&header
.version
);
203 be64_to_cpus(&header
.backing_file_offset
);
204 be32_to_cpus(&header
.backing_file_size
);
205 be64_to_cpus(&header
.size
);
206 be32_to_cpus(&header
.cluster_bits
);
207 be32_to_cpus(&header
.crypt_method
);
208 be64_to_cpus(&header
.l1_table_offset
);
209 be32_to_cpus(&header
.l1_size
);
210 be64_to_cpus(&header
.refcount_table_offset
);
211 be32_to_cpus(&header
.refcount_table_clusters
);
212 be64_to_cpus(&header
.snapshots_offset
);
213 be32_to_cpus(&header
.nb_snapshots
);
215 if (header
.magic
!= QCOW_MAGIC
|| header
.version
!= QCOW_VERSION
)
217 if (header
.size
<= 1 ||
218 header
.cluster_bits
< 9 ||
219 header
.cluster_bits
> 16)
221 if (header
.crypt_method
> QCOW_CRYPT_AES
)
223 s
->crypt_method_header
= header
.crypt_method
;
224 if (s
->crypt_method_header
)
226 s
->cluster_bits
= header
.cluster_bits
;
227 s
->cluster_size
= 1 << s
->cluster_bits
;
228 s
->cluster_sectors
= 1 << (s
->cluster_bits
- 9);
229 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
230 s
->l2_size
= 1 << s
->l2_bits
;
231 bs
->total_sectors
= header
.size
/ 512;
232 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
233 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
234 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
235 s
->refcount_table_offset
= header
.refcount_table_offset
;
236 s
->refcount_table_size
=
237 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
239 s
->snapshots_offset
= header
.snapshots_offset
;
240 s
->nb_snapshots
= header
.nb_snapshots
;
242 /* read the level 1 table */
243 s
->l1_size
= header
.l1_size
;
244 shift
= s
->cluster_bits
+ s
->l2_bits
;
245 s
->l1_vm_state_index
= (header
.size
+ (1LL << shift
) - 1) >> shift
;
246 /* the L1 table must contain at least enough entries to put
248 if (s
->l1_size
< s
->l1_vm_state_index
)
250 s
->l1_table_offset
= header
.l1_table_offset
;
251 s
->l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
254 if (bdrv_pread(s
->hd
, s
->l1_table_offset
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
255 s
->l1_size
* sizeof(uint64_t))
257 for(i
= 0;i
< s
->l1_size
; i
++) {
258 be64_to_cpus(&s
->l1_table
[i
]);
261 s
->l2_cache
= qemu_malloc(s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
264 s
->cluster_cache
= qemu_malloc(s
->cluster_size
);
265 if (!s
->cluster_cache
)
267 /* one more sector for decompressed data alignment */
268 s
->cluster_data
= qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
270 if (!s
->cluster_data
)
272 s
->cluster_cache_offset
= -1;
274 if (refcount_init(bs
) < 0)
277 /* read the backing file name */
278 if (header
.backing_file_offset
!= 0) {
279 len
= header
.backing_file_size
;
282 if (bdrv_pread(s
->hd
, header
.backing_file_offset
, bs
->backing_file
, len
) != len
)
284 bs
->backing_file
[len
] = '\0';
286 if (qcow_read_snapshots(bs
) < 0)
295 qcow_free_snapshots(bs
);
297 qemu_free(s
->l1_table
);
298 qemu_free(s
->l2_cache
);
299 qemu_free(s
->cluster_cache
);
300 qemu_free(s
->cluster_data
);
305 static int qcow_set_key(BlockDriverState
*bs
, const char *key
)
307 BDRVQcowState
*s
= bs
->opaque
;
311 memset(keybuf
, 0, 16);
315 /* XXX: we could compress the chars to 7 bits to increase
317 for(i
= 0;i
< len
;i
++) {
320 s
->crypt_method
= s
->crypt_method_header
;
322 if (AES_set_encrypt_key(keybuf
, 128, &s
->aes_encrypt_key
) != 0)
324 if (AES_set_decrypt_key(keybuf
, 128, &s
->aes_decrypt_key
) != 0)
334 AES_encrypt(in
, tmp
, &s
->aes_encrypt_key
);
335 AES_decrypt(tmp
, out
, &s
->aes_decrypt_key
);
336 for(i
= 0; i
< 16; i
++)
337 printf(" %02x", tmp
[i
]);
339 for(i
= 0; i
< 16; i
++)
340 printf(" %02x", out
[i
]);
347 /* The crypt function is compatible with the linux cryptoloop
348 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
350 static void encrypt_sectors(BDRVQcowState
*s
, int64_t sector_num
,
351 uint8_t *out_buf
, const uint8_t *in_buf
,
352 int nb_sectors
, int enc
,
361 for(i
= 0; i
< nb_sectors
; i
++) {
362 ivec
.ll
[0] = cpu_to_le64(sector_num
);
364 AES_cbc_encrypt(in_buf
, out_buf
, 512, key
,
372 static int copy_sectors(BlockDriverState
*bs
, uint64_t start_sect
,
373 uint64_t cluster_offset
, int n_start
, int n_end
)
375 BDRVQcowState
*s
= bs
->opaque
;
381 ret
= qcow_read(bs
, start_sect
+ n_start
, s
->cluster_data
, n
);
384 if (s
->crypt_method
) {
385 encrypt_sectors(s
, start_sect
+ n_start
,
387 s
->cluster_data
, n
, 1,
388 &s
->aes_encrypt_key
);
390 ret
= bdrv_write(s
->hd
, (cluster_offset
>> 9) + n_start
,
397 static void l2_cache_reset(BlockDriverState
*bs
)
399 BDRVQcowState
*s
= bs
->opaque
;
401 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
402 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
403 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
406 static inline int l2_cache_new_entry(BlockDriverState
*bs
)
408 BDRVQcowState
*s
= bs
->opaque
;
412 /* find a new entry in the least used one */
414 min_count
= 0xffffffff;
415 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
416 if (s
->l2_cache_counts
[i
] < min_count
) {
417 min_count
= s
->l2_cache_counts
[i
];
424 static int64_t align_offset(int64_t offset
, int n
)
426 offset
= (offset
+ n
- 1) & ~(n
- 1);
430 static int grow_l1_table(BlockDriverState
*bs
, int min_size
)
432 BDRVQcowState
*s
= bs
->opaque
;
433 int new_l1_size
, new_l1_size2
, ret
, i
;
434 uint64_t *new_l1_table
;
435 uint64_t new_l1_table_offset
;
439 new_l1_size
= s
->l1_size
;
440 if (min_size
<= new_l1_size
)
442 while (min_size
> new_l1_size
) {
443 new_l1_size
= (new_l1_size
* 3 + 1) / 2;
446 printf("grow l1_table from %d to %d\n", s
->l1_size
, new_l1_size
);
449 new_l1_size2
= sizeof(uint64_t) * new_l1_size
;
450 new_l1_table
= qemu_mallocz(new_l1_size2
);
453 memcpy(new_l1_table
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t));
455 /* write new table (align to cluster) */
456 new_l1_table_offset
= alloc_clusters(bs
, new_l1_size2
);
458 for(i
= 0; i
< s
->l1_size
; i
++)
459 new_l1_table
[i
] = cpu_to_be64(new_l1_table
[i
]);
460 ret
= bdrv_pwrite(s
->hd
, new_l1_table_offset
, new_l1_table
, new_l1_size2
);
461 if (ret
!= new_l1_size2
)
463 for(i
= 0; i
< s
->l1_size
; i
++)
464 new_l1_table
[i
] = be64_to_cpu(new_l1_table
[i
]);
467 data64
= cpu_to_be64(new_l1_table_offset
);
468 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_table_offset
),
469 &data64
, sizeof(data64
)) != sizeof(data64
))
471 data32
= cpu_to_be32(new_l1_size
);
472 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_size
),
473 &data32
, sizeof(data32
)) != sizeof(data32
))
475 qemu_free(s
->l1_table
);
476 free_clusters(bs
, s
->l1_table_offset
, s
->l1_size
* sizeof(uint64_t));
477 s
->l1_table_offset
= new_l1_table_offset
;
478 s
->l1_table
= new_l1_table
;
479 s
->l1_size
= new_l1_size
;
482 qemu_free(s
->l1_table
);
489 * seek l2_offset in the l2_cache table
490 * if not found, return NULL,
492 * increments the l2 cache hit count of the entry,
493 * if counter overflow, divide by two all counters
494 * return the pointer to the l2 cache entry
498 static uint64_t *seek_l2_table(BDRVQcowState
*s
, uint64_t l2_offset
)
502 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
503 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
504 /* increment the hit count */
505 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
506 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
507 s
->l2_cache_counts
[j
] >>= 1;
510 return s
->l2_cache
+ (i
<< s
->l2_bits
);
519 * Loads a L2 table into memory. If the table is in the cache, the cache
520 * is used; otherwise the L2 table is loaded from the image file.
522 * Returns a pointer to the L2 table on success, or NULL if the read from
523 * the image file failed.
526 static uint64_t *l2_load(BlockDriverState
*bs
, uint64_t l2_offset
)
528 BDRVQcowState
*s
= bs
->opaque
;
532 /* seek if the table for the given offset is in the cache */
534 l2_table
= seek_l2_table(s
, l2_offset
);
535 if (l2_table
!= NULL
)
538 /* not found: load a new entry in the least used one */
540 min_index
= l2_cache_new_entry(bs
);
541 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
542 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
543 s
->l2_size
* sizeof(uint64_t))
545 s
->l2_cache_offsets
[min_index
] = l2_offset
;
546 s
->l2_cache_counts
[min_index
] = 1;
554 * Allocate a new l2 entry in the file. If l1_index points to an already
555 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
556 * table) copy the contents of the old L2 table into the newly allocated one.
557 * Otherwise the new table is initialized with zeros.
561 static uint64_t *l2_allocate(BlockDriverState
*bs
, int l1_index
)
563 BDRVQcowState
*s
= bs
->opaque
;
565 uint64_t old_l2_offset
, tmp
;
566 uint64_t *l2_table
, l2_offset
;
568 old_l2_offset
= s
->l1_table
[l1_index
];
570 /* allocate a new l2 entry */
572 l2_offset
= alloc_clusters(bs
, s
->l2_size
* sizeof(uint64_t));
574 /* update the L1 entry */
576 s
->l1_table
[l1_index
] = l2_offset
| QCOW_OFLAG_COPIED
;
578 tmp
= cpu_to_be64(l2_offset
| QCOW_OFLAG_COPIED
);
579 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
+ l1_index
* sizeof(tmp
),
580 &tmp
, sizeof(tmp
)) != sizeof(tmp
))
583 /* allocate a new entry in the l2 cache */
585 min_index
= l2_cache_new_entry(bs
);
586 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
588 if (old_l2_offset
== 0) {
589 /* if there was no old l2 table, clear the new table */
590 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
592 /* if there was an old l2 table, read it from the disk */
593 if (bdrv_pread(s
->hd
, old_l2_offset
,
594 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
595 s
->l2_size
* sizeof(uint64_t))
598 /* write the l2 table to the file */
599 if (bdrv_pwrite(s
->hd
, l2_offset
,
600 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
601 s
->l2_size
* sizeof(uint64_t))
604 /* update the l2 cache entry */
606 s
->l2_cache_offsets
[min_index
] = l2_offset
;
607 s
->l2_cache_counts
[min_index
] = 1;
615 * For a given offset of the disk image, return cluster offset in
618 * on entry, *num is the number of contiguous clusters we'd like to
619 * access following offset.
621 * on exit, *num is the number of contiguous clusters we can read.
623 * Return 1, if the offset is found
624 * Return 0, otherwise.
628 static uint64_t get_cluster_offset(BlockDriverState
*bs
,
629 uint64_t offset
, int *num
)
631 BDRVQcowState
*s
= bs
->opaque
;
632 int l1_index
, l2_index
;
633 uint64_t l2_offset
, *l2_table
, cluster_offset
, next
;
635 int index_in_cluster
, nb_available
, nb_needed
;
637 index_in_cluster
= (offset
>> 9) & (s
->cluster_sectors
- 1);
638 nb_needed
= *num
+ index_in_cluster
;
640 l1_bits
= s
->l2_bits
+ s
->cluster_bits
;
642 /* compute how many bytes there are between the offset and
643 * and the end of the l1 entry
646 nb_available
= (1 << l1_bits
) - (offset
& ((1 << l1_bits
) - 1));
648 /* compute the number of available sectors */
650 nb_available
= (nb_available
>> 9) + index_in_cluster
;
654 /* seek the the l2 offset in the l1 table */
656 l1_index
= offset
>> l1_bits
;
657 if (l1_index
>= s
->l1_size
)
660 l2_offset
= s
->l1_table
[l1_index
];
662 /* seek the l2 table of the given l2 offset */
667 /* load the l2 table in memory */
669 l2_offset
&= ~QCOW_OFLAG_COPIED
;
670 l2_table
= l2_load(bs
, l2_offset
);
671 if (l2_table
== NULL
)
674 /* find the cluster offset for the given disk offset */
676 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
677 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
678 nb_available
= s
->cluster_sectors
;
681 if (!cluster_offset
) {
683 /* how many empty clusters ? */
685 while (nb_available
< nb_needed
&& !l2_table
[l2_index
]) {
687 nb_available
+= s
->cluster_sectors
;
691 /* how many allocated clusters ? */
693 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
694 while (nb_available
< nb_needed
) {
695 next
= be64_to_cpu(l2_table
[l2_index
]) & ~QCOW_OFLAG_COPIED
;
696 if (next
!= cluster_offset
+ (nb_available
<< 9))
699 nb_available
+= s
->cluster_sectors
;
704 if (nb_available
> nb_needed
)
705 nb_available
= nb_needed
;
707 *num
= nb_available
- index_in_cluster
;
709 return cluster_offset
;
715 * free clusters according to its type: compressed or not
719 static void free_any_clusters(BlockDriverState
*bs
,
720 uint64_t cluster_offset
, int nb_clusters
)
722 BDRVQcowState
*s
= bs
->opaque
;
724 /* free the cluster */
726 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
728 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) &
730 free_clusters(bs
, (cluster_offset
& s
->cluster_offset_mask
) & ~511,
735 free_clusters(bs
, cluster_offset
, nb_clusters
<< s
->cluster_bits
);
743 * for a given disk offset, load (and allocate if needed)
746 * the l2 table offset in the qcow2 file and the cluster index
747 * in the l2 table are given to the caller.
751 static int get_cluster_table(BlockDriverState
*bs
, uint64_t offset
,
752 uint64_t **new_l2_table
,
753 uint64_t *new_l2_offset
,
756 BDRVQcowState
*s
= bs
->opaque
;
757 int l1_index
, l2_index
, ret
;
758 uint64_t l2_offset
, *l2_table
;
760 /* seek the the l2 offset in the l1 table */
762 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
763 if (l1_index
>= s
->l1_size
) {
764 ret
= grow_l1_table(bs
, l1_index
+ 1);
768 l2_offset
= s
->l1_table
[l1_index
];
770 /* seek the l2 table of the given l2 offset */
772 if (l2_offset
& QCOW_OFLAG_COPIED
) {
773 /* load the l2 table in memory */
774 l2_offset
&= ~QCOW_OFLAG_COPIED
;
775 l2_table
= l2_load(bs
, l2_offset
);
776 if (l2_table
== NULL
)
780 free_clusters(bs
, l2_offset
, s
->l2_size
* sizeof(uint64_t));
781 l2_table
= l2_allocate(bs
, l1_index
);
782 if (l2_table
== NULL
)
784 l2_offset
= s
->l1_table
[l1_index
] & ~QCOW_OFLAG_COPIED
;
787 /* find the cluster offset for the given disk offset */
789 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
791 *new_l2_table
= l2_table
;
792 *new_l2_offset
= l2_offset
;
793 *new_l2_index
= l2_index
;
799 * alloc_compressed_cluster_offset
801 * For a given offset of the disk image, return cluster offset in
804 * If the offset is not found, allocate a new compressed cluster.
806 * Return the cluster offset if successful,
807 * Return 0, otherwise.
811 static uint64_t alloc_compressed_cluster_offset(BlockDriverState
*bs
,
815 BDRVQcowState
*s
= bs
->opaque
;
817 uint64_t l2_offset
, *l2_table
, cluster_offset
;
820 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
824 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
825 if (cluster_offset
& QCOW_OFLAG_COPIED
)
826 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
829 free_any_clusters(bs
, cluster_offset
, 1);
831 cluster_offset
= alloc_bytes(bs
, compressed_size
);
832 nb_csectors
= ((cluster_offset
+ compressed_size
- 1) >> 9) -
833 (cluster_offset
>> 9);
835 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
836 ((uint64_t)nb_csectors
<< s
->csize_shift
);
838 /* update L2 table */
840 /* compressed clusters never have the copied flag */
842 l2_table
[l2_index
] = cpu_to_be64(cluster_offset
);
843 if (bdrv_pwrite(s
->hd
,
844 l2_offset
+ l2_index
* sizeof(uint64_t),
846 sizeof(uint64_t)) != sizeof(uint64_t))
849 return cluster_offset
;
853 * alloc_cluster_offset
855 * For a given offset of the disk image, return cluster offset in
858 * If the offset is not found, allocate a new cluster.
860 * Return the cluster offset if successful,
861 * Return 0, otherwise.
865 static uint64_t alloc_cluster_offset(BlockDriverState
*bs
,
867 int n_start
, int n_end
,
870 BDRVQcowState
*s
= bs
->opaque
;
872 uint64_t l2_offset
, *l2_table
, cluster_offset
;
873 int nb_available
, nb_clusters
, i
;
874 uint64_t start_sect
, current
;
876 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
880 nb_clusters
= ((n_end
<< 9) + s
->cluster_size
- 1) >>
882 if (nb_clusters
> s
->l2_size
- l2_index
)
883 nb_clusters
= s
->l2_size
- l2_index
;
885 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
887 /* We keep all QCOW_OFLAG_COPIED clusters */
889 if (cluster_offset
& QCOW_OFLAG_COPIED
) {
891 for (i
= 1; i
< nb_clusters
; i
++) {
892 current
= be64_to_cpu(l2_table
[l2_index
+ i
]);
893 if (cluster_offset
+ (i
<< s
->cluster_bits
) != current
)
898 nb_available
= nb_clusters
<< (s
->cluster_bits
- 9);
899 if (nb_available
> n_end
)
900 nb_available
= n_end
;
902 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
907 /* for the moment, multiple compressed clusters are not managed */
909 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
)
912 /* how many empty or how many to free ? */
914 if (!cluster_offset
) {
916 /* how many free clusters ? */
919 while (i
< nb_clusters
&&
920 l2_table
[l2_index
+ i
] == 0) {
927 /* how many contiguous clusters ? */
929 for (i
= 1; i
< nb_clusters
; i
++) {
930 current
= be64_to_cpu(l2_table
[l2_index
+ i
]);
931 if (cluster_offset
+ (i
<< s
->cluster_bits
) != current
)
936 free_any_clusters(bs
, cluster_offset
, i
);
939 /* allocate a new cluster */
941 cluster_offset
= alloc_clusters(bs
, nb_clusters
* s
->cluster_size
);
943 /* we must initialize the cluster content which won't be
946 nb_available
= nb_clusters
<< (s
->cluster_bits
- 9);
947 if (nb_available
> n_end
)
948 nb_available
= n_end
;
950 /* copy content of unmodified sectors */
952 start_sect
= (offset
& ~(s
->cluster_size
- 1)) >> 9;
954 ret
= copy_sectors(bs
, start_sect
, cluster_offset
, 0, n_start
);
959 if (nb_available
& (s
->cluster_sectors
- 1)) {
960 uint64_t end
= nb_available
& ~(uint64_t)(s
->cluster_sectors
- 1);
961 ret
= copy_sectors(bs
, start_sect
+ end
,
962 cluster_offset
+ (end
<< 9),
969 /* update L2 table */
971 for (i
= 0; i
< nb_clusters
; i
++)
972 l2_table
[l2_index
+ i
] = cpu_to_be64((cluster_offset
+
973 (i
<< s
->cluster_bits
)) |
976 if (bdrv_pwrite(s
->hd
,
977 l2_offset
+ l2_index
* sizeof(uint64_t),
979 nb_clusters
* sizeof(uint64_t)) !=
980 nb_clusters
* sizeof(uint64_t))
984 *num
= nb_available
- n_start
;
986 return cluster_offset
;
989 static int qcow_is_allocated(BlockDriverState
*bs
, int64_t sector_num
,
990 int nb_sectors
, int *pnum
)
992 uint64_t cluster_offset
;
995 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, pnum
);
997 return (cluster_offset
!= 0);
1000 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
1001 const uint8_t *buf
, int buf_size
)
1003 z_stream strm1
, *strm
= &strm1
;
1006 memset(strm
, 0, sizeof(*strm
));
1008 strm
->next_in
= (uint8_t *)buf
;
1009 strm
->avail_in
= buf_size
;
1010 strm
->next_out
= out_buf
;
1011 strm
->avail_out
= out_buf_size
;
1013 ret
= inflateInit2(strm
, -12);
1016 ret
= inflate(strm
, Z_FINISH
);
1017 out_len
= strm
->next_out
- out_buf
;
1018 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
1019 out_len
!= out_buf_size
) {
1027 static int decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
)
1029 int ret
, csize
, nb_csectors
, sector_offset
;
1032 coffset
= cluster_offset
& s
->cluster_offset_mask
;
1033 if (s
->cluster_cache_offset
!= coffset
) {
1034 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
1035 sector_offset
= coffset
& 511;
1036 csize
= nb_csectors
* 512 - sector_offset
;
1037 ret
= bdrv_read(s
->hd
, coffset
>> 9, s
->cluster_data
, nb_csectors
);
1041 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
1042 s
->cluster_data
+ sector_offset
, csize
) < 0) {
1045 s
->cluster_cache_offset
= coffset
;
1050 /* handle reading after the end of the backing file */
1051 static int backing_read1(BlockDriverState
*bs
,
1052 int64_t sector_num
, uint8_t *buf
, int nb_sectors
)
1055 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
1057 if (sector_num
>= bs
->total_sectors
)
1060 n1
= bs
->total_sectors
- sector_num
;
1061 memset(buf
+ n1
* 512, 0, 512 * (nb_sectors
- n1
));
1065 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
1066 uint8_t *buf
, int nb_sectors
)
1068 BDRVQcowState
*s
= bs
->opaque
;
1069 int ret
, index_in_cluster
, n
, n1
;
1070 uint64_t cluster_offset
;
1072 while (nb_sectors
> 0) {
1074 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, &n
);
1075 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1076 if (!cluster_offset
) {
1077 if (bs
->backing_hd
) {
1078 /* read from the base image */
1079 n1
= backing_read1(bs
->backing_hd
, sector_num
, buf
, n
);
1081 ret
= bdrv_read(bs
->backing_hd
, sector_num
, buf
, n1
);
1086 memset(buf
, 0, 512 * n
);
1088 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1089 if (decompress_cluster(s
, cluster_offset
) < 0)
1091 memcpy(buf
, s
->cluster_cache
+ index_in_cluster
* 512, 512 * n
);
1093 ret
= bdrv_pread(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1096 if (s
->crypt_method
) {
1097 encrypt_sectors(s
, sector_num
, buf
, buf
, n
, 0,
1098 &s
->aes_decrypt_key
);
1108 static int qcow_write(BlockDriverState
*bs
, int64_t sector_num
,
1109 const uint8_t *buf
, int nb_sectors
)
1111 BDRVQcowState
*s
= bs
->opaque
;
1112 int ret
, index_in_cluster
, n
;
1113 uint64_t cluster_offset
;
1116 while (nb_sectors
> 0) {
1117 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1118 n_end
= index_in_cluster
+ nb_sectors
;
1119 if (s
->crypt_method
&&
1120 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1121 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1122 cluster_offset
= alloc_cluster_offset(bs
, sector_num
<< 9,
1125 if (!cluster_offset
)
1127 if (s
->crypt_method
) {
1128 encrypt_sectors(s
, sector_num
, s
->cluster_data
, buf
, n
, 1,
1129 &s
->aes_encrypt_key
);
1130 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512,
1131 s
->cluster_data
, n
* 512);
1133 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1141 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1145 typedef struct QCowAIOCB
{
1146 BlockDriverAIOCB common
;
1151 uint64_t cluster_offset
;
1152 uint8_t *cluster_data
;
1153 BlockDriverAIOCB
*hd_aiocb
;
1156 static void qcow_aio_read_cb(void *opaque
, int ret
)
1158 QCowAIOCB
*acb
= opaque
;
1159 BlockDriverState
*bs
= acb
->common
.bs
;
1160 BDRVQcowState
*s
= bs
->opaque
;
1161 int index_in_cluster
, n1
;
1163 acb
->hd_aiocb
= NULL
;
1166 acb
->common
.cb(acb
->common
.opaque
, ret
);
1167 qemu_aio_release(acb
);
1172 /* post process the read buffer */
1173 if (!acb
->cluster_offset
) {
1175 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1178 if (s
->crypt_method
) {
1179 encrypt_sectors(s
, acb
->sector_num
, acb
->buf
, acb
->buf
,
1181 &s
->aes_decrypt_key
);
1185 acb
->nb_sectors
-= acb
->n
;
1186 acb
->sector_num
+= acb
->n
;
1187 acb
->buf
+= acb
->n
* 512;
1189 if (acb
->nb_sectors
== 0) {
1190 /* request completed */
1191 acb
->common
.cb(acb
->common
.opaque
, 0);
1192 qemu_aio_release(acb
);
1196 /* prepare next AIO request */
1197 acb
->n
= acb
->nb_sectors
;
1198 acb
->cluster_offset
= get_cluster_offset(bs
, acb
->sector_num
<< 9, &acb
->n
);
1199 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1201 if (!acb
->cluster_offset
) {
1202 if (bs
->backing_hd
) {
1203 /* read from the base image */
1204 n1
= backing_read1(bs
->backing_hd
, acb
->sector_num
,
1207 acb
->hd_aiocb
= bdrv_aio_read(bs
->backing_hd
, acb
->sector_num
,
1208 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1209 if (acb
->hd_aiocb
== NULL
)
1215 /* Note: in this case, no need to wait */
1216 memset(acb
->buf
, 0, 512 * acb
->n
);
1219 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1220 /* add AIO support for compressed blocks ? */
1221 if (decompress_cluster(s
, acb
->cluster_offset
) < 0)
1224 s
->cluster_cache
+ index_in_cluster
* 512, 512 * acb
->n
);
1227 if ((acb
->cluster_offset
& 511) != 0) {
1231 acb
->hd_aiocb
= bdrv_aio_read(s
->hd
,
1232 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1233 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1234 if (acb
->hd_aiocb
== NULL
)
1239 static QCowAIOCB
*qcow_aio_setup(BlockDriverState
*bs
,
1240 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1241 BlockDriverCompletionFunc
*cb
, void *opaque
)
1245 acb
= qemu_aio_get(bs
, cb
, opaque
);
1248 acb
->hd_aiocb
= NULL
;
1249 acb
->sector_num
= sector_num
;
1251 acb
->nb_sectors
= nb_sectors
;
1253 acb
->cluster_offset
= 0;
1257 static BlockDriverAIOCB
*qcow_aio_read(BlockDriverState
*bs
,
1258 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1259 BlockDriverCompletionFunc
*cb
, void *opaque
)
1263 acb
= qcow_aio_setup(bs
, sector_num
, buf
, nb_sectors
, cb
, opaque
);
1267 qcow_aio_read_cb(acb
, 0);
1268 return &acb
->common
;
1271 static void qcow_aio_write_cb(void *opaque
, int ret
)
1273 QCowAIOCB
*acb
= opaque
;
1274 BlockDriverState
*bs
= acb
->common
.bs
;
1275 BDRVQcowState
*s
= bs
->opaque
;
1276 int index_in_cluster
;
1277 uint64_t cluster_offset
;
1278 const uint8_t *src_buf
;
1281 acb
->hd_aiocb
= NULL
;
1285 acb
->common
.cb(acb
->common
.opaque
, ret
);
1286 qemu_aio_release(acb
);
1290 acb
->nb_sectors
-= acb
->n
;
1291 acb
->sector_num
+= acb
->n
;
1292 acb
->buf
+= acb
->n
* 512;
1294 if (acb
->nb_sectors
== 0) {
1295 /* request completed */
1296 acb
->common
.cb(acb
->common
.opaque
, 0);
1297 qemu_aio_release(acb
);
1301 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1302 n_end
= index_in_cluster
+ acb
->nb_sectors
;
1303 if (s
->crypt_method
&&
1304 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1305 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1307 cluster_offset
= alloc_cluster_offset(bs
, acb
->sector_num
<< 9,
1310 if (!cluster_offset
|| (cluster_offset
& 511) != 0) {
1314 if (s
->crypt_method
) {
1315 if (!acb
->cluster_data
) {
1316 acb
->cluster_data
= qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS
*
1318 if (!acb
->cluster_data
) {
1323 encrypt_sectors(s
, acb
->sector_num
, acb
->cluster_data
, acb
->buf
,
1324 acb
->n
, 1, &s
->aes_encrypt_key
);
1325 src_buf
= acb
->cluster_data
;
1329 acb
->hd_aiocb
= bdrv_aio_write(s
->hd
,
1330 (cluster_offset
>> 9) + index_in_cluster
,
1332 qcow_aio_write_cb
, acb
);
1333 if (acb
->hd_aiocb
== NULL
)
1337 static BlockDriverAIOCB
*qcow_aio_write(BlockDriverState
*bs
,
1338 int64_t sector_num
, const uint8_t *buf
, int nb_sectors
,
1339 BlockDriverCompletionFunc
*cb
, void *opaque
)
1341 BDRVQcowState
*s
= bs
->opaque
;
1344 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1346 acb
= qcow_aio_setup(bs
, sector_num
, (uint8_t*)buf
, nb_sectors
, cb
, opaque
);
1350 qcow_aio_write_cb(acb
, 0);
1351 return &acb
->common
;
1354 static void qcow_aio_cancel(BlockDriverAIOCB
*blockacb
)
1356 QCowAIOCB
*acb
= (QCowAIOCB
*)blockacb
;
1358 bdrv_aio_cancel(acb
->hd_aiocb
);
1359 qemu_aio_release(acb
);
1362 static void qcow_close(BlockDriverState
*bs
)
1364 BDRVQcowState
*s
= bs
->opaque
;
1365 qemu_free(s
->l1_table
);
1366 qemu_free(s
->l2_cache
);
1367 qemu_free(s
->cluster_cache
);
1368 qemu_free(s
->cluster_data
);
1373 /* XXX: use std qcow open function ? */
1374 typedef struct QCowCreateState
{
1377 uint16_t *refcount_block
;
1378 uint64_t *refcount_table
;
1379 int64_t l1_table_offset
;
1380 int64_t refcount_table_offset
;
1381 int64_t refcount_block_offset
;
1384 static void create_refcount_update(QCowCreateState
*s
,
1385 int64_t offset
, int64_t size
)
1388 int64_t start
, last
, cluster_offset
;
1391 start
= offset
& ~(s
->cluster_size
- 1);
1392 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
1393 for(cluster_offset
= start
; cluster_offset
<= last
;
1394 cluster_offset
+= s
->cluster_size
) {
1395 p
= &s
->refcount_block
[cluster_offset
>> s
->cluster_bits
];
1396 refcount
= be16_to_cpu(*p
);
1398 *p
= cpu_to_be16(refcount
);
1402 static int qcow_create(const char *filename
, int64_t total_size
,
1403 const char *backing_file
, int flags
)
1405 int fd
, header_size
, backing_filename_len
, l1_size
, i
, shift
, l2_bits
;
1407 uint64_t tmp
, offset
;
1408 QCowCreateState s1
, *s
= &s1
;
1410 memset(s
, 0, sizeof(*s
));
1412 fd
= open(filename
, O_WRONLY
| O_CREAT
| O_TRUNC
| O_BINARY
, 0644);
1415 memset(&header
, 0, sizeof(header
));
1416 header
.magic
= cpu_to_be32(QCOW_MAGIC
);
1417 header
.version
= cpu_to_be32(QCOW_VERSION
);
1418 header
.size
= cpu_to_be64(total_size
* 512);
1419 header_size
= sizeof(header
);
1420 backing_filename_len
= 0;
1422 header
.backing_file_offset
= cpu_to_be64(header_size
);
1423 backing_filename_len
= strlen(backing_file
);
1424 header
.backing_file_size
= cpu_to_be32(backing_filename_len
);
1425 header_size
+= backing_filename_len
;
1427 s
->cluster_bits
= 12; /* 4 KB clusters */
1428 s
->cluster_size
= 1 << s
->cluster_bits
;
1429 header
.cluster_bits
= cpu_to_be32(s
->cluster_bits
);
1430 header_size
= (header_size
+ 7) & ~7;
1431 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1432 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1434 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1436 l2_bits
= s
->cluster_bits
- 3;
1437 shift
= s
->cluster_bits
+ l2_bits
;
1438 l1_size
= (((total_size
* 512) + (1LL << shift
) - 1) >> shift
);
1439 offset
= align_offset(header_size
, s
->cluster_size
);
1440 s
->l1_table_offset
= offset
;
1441 header
.l1_table_offset
= cpu_to_be64(s
->l1_table_offset
);
1442 header
.l1_size
= cpu_to_be32(l1_size
);
1443 offset
+= align_offset(l1_size
* sizeof(uint64_t), s
->cluster_size
);
1445 s
->refcount_table
= qemu_mallocz(s
->cluster_size
);
1446 if (!s
->refcount_table
)
1448 s
->refcount_block
= qemu_mallocz(s
->cluster_size
);
1449 if (!s
->refcount_block
)
1452 s
->refcount_table_offset
= offset
;
1453 header
.refcount_table_offset
= cpu_to_be64(offset
);
1454 header
.refcount_table_clusters
= cpu_to_be32(1);
1455 offset
+= s
->cluster_size
;
1457 s
->refcount_table
[0] = cpu_to_be64(offset
);
1458 s
->refcount_block_offset
= offset
;
1459 offset
+= s
->cluster_size
;
1461 /* update refcounts */
1462 create_refcount_update(s
, 0, header_size
);
1463 create_refcount_update(s
, s
->l1_table_offset
, l1_size
* sizeof(uint64_t));
1464 create_refcount_update(s
, s
->refcount_table_offset
, s
->cluster_size
);
1465 create_refcount_update(s
, s
->refcount_block_offset
, s
->cluster_size
);
1467 /* write all the data */
1468 write(fd
, &header
, sizeof(header
));
1470 write(fd
, backing_file
, backing_filename_len
);
1472 lseek(fd
, s
->l1_table_offset
, SEEK_SET
);
1474 for(i
= 0;i
< l1_size
; i
++) {
1475 write(fd
, &tmp
, sizeof(tmp
));
1477 lseek(fd
, s
->refcount_table_offset
, SEEK_SET
);
1478 write(fd
, s
->refcount_table
, s
->cluster_size
);
1480 lseek(fd
, s
->refcount_block_offset
, SEEK_SET
);
1481 write(fd
, s
->refcount_block
, s
->cluster_size
);
1483 qemu_free(s
->refcount_table
);
1484 qemu_free(s
->refcount_block
);
1488 qemu_free(s
->refcount_table
);
1489 qemu_free(s
->refcount_block
);
1494 static int qcow_make_empty(BlockDriverState
*bs
)
1497 /* XXX: not correct */
1498 BDRVQcowState
*s
= bs
->opaque
;
1499 uint32_t l1_length
= s
->l1_size
* sizeof(uint64_t);
1502 memset(s
->l1_table
, 0, l1_length
);
1503 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
, s
->l1_table
, l1_length
) < 0)
1505 ret
= bdrv_truncate(s
->hd
, s
->l1_table_offset
+ l1_length
);
1514 /* XXX: put compressed sectors first, then all the cluster aligned
1515 tables to avoid losing bytes in alignment */
1516 static int qcow_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1517 const uint8_t *buf
, int nb_sectors
)
1519 BDRVQcowState
*s
= bs
->opaque
;
1523 uint64_t cluster_offset
;
1525 if (nb_sectors
== 0) {
1526 /* align end of file to a sector boundary to ease reading with
1527 sector based I/Os */
1528 cluster_offset
= bdrv_getlength(s
->hd
);
1529 cluster_offset
= (cluster_offset
+ 511) & ~511;
1530 bdrv_truncate(s
->hd
, cluster_offset
);
1534 if (nb_sectors
!= s
->cluster_sectors
)
1537 out_buf
= qemu_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
1541 /* best compression, small window, no zlib header */
1542 memset(&strm
, 0, sizeof(strm
));
1543 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1545 9, Z_DEFAULT_STRATEGY
);
1551 strm
.avail_in
= s
->cluster_size
;
1552 strm
.next_in
= (uint8_t *)buf
;
1553 strm
.avail_out
= s
->cluster_size
;
1554 strm
.next_out
= out_buf
;
1556 ret
= deflate(&strm
, Z_FINISH
);
1557 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1562 out_len
= strm
.next_out
- out_buf
;
1566 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1567 /* could not compress: write normal cluster */
1568 qcow_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
1570 cluster_offset
= alloc_compressed_cluster_offset(bs
, sector_num
<< 9,
1572 if (!cluster_offset
)
1574 cluster_offset
&= s
->cluster_offset_mask
;
1575 if (bdrv_pwrite(s
->hd
, cluster_offset
, out_buf
, out_len
) != out_len
) {
1585 static void qcow_flush(BlockDriverState
*bs
)
1587 BDRVQcowState
*s
= bs
->opaque
;
1591 static int qcow_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
1593 BDRVQcowState
*s
= bs
->opaque
;
1594 bdi
->cluster_size
= s
->cluster_size
;
1595 bdi
->vm_state_offset
= (int64_t)s
->l1_vm_state_index
<<
1596 (s
->cluster_bits
+ s
->l2_bits
);
1600 /*********************************************************/
1601 /* snapshot support */
1603 /* update the refcounts of snapshots and the copied flag */
1604 static int update_snapshot_refcount(BlockDriverState
*bs
,
1605 int64_t l1_table_offset
,
1609 BDRVQcowState
*s
= bs
->opaque
;
1610 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
, l1_allocated
;
1611 int64_t old_offset
, old_l2_offset
;
1612 int l2_size
, i
, j
, l1_modified
, l2_modified
, nb_csectors
, refcount
;
1618 l1_size2
= l1_size
* sizeof(uint64_t);
1620 if (l1_table_offset
!= s
->l1_table_offset
) {
1621 l1_table
= qemu_malloc(l1_size2
);
1625 if (bdrv_pread(s
->hd
, l1_table_offset
,
1626 l1_table
, l1_size2
) != l1_size2
)
1628 for(i
= 0;i
< l1_size
; i
++)
1629 be64_to_cpus(&l1_table
[i
]);
1631 assert(l1_size
== s
->l1_size
);
1632 l1_table
= s
->l1_table
;
1636 l2_size
= s
->l2_size
* sizeof(uint64_t);
1637 l2_table
= qemu_malloc(l2_size
);
1641 for(i
= 0; i
< l1_size
; i
++) {
1642 l2_offset
= l1_table
[i
];
1644 old_l2_offset
= l2_offset
;
1645 l2_offset
&= ~QCOW_OFLAG_COPIED
;
1647 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
1649 for(j
= 0; j
< s
->l2_size
; j
++) {
1650 offset
= be64_to_cpu(l2_table
[j
]);
1652 old_offset
= offset
;
1653 offset
&= ~QCOW_OFLAG_COPIED
;
1654 if (offset
& QCOW_OFLAG_COMPRESSED
) {
1655 nb_csectors
= ((offset
>> s
->csize_shift
) &
1658 update_refcount(bs
, (offset
& s
->cluster_offset_mask
) & ~511,
1659 nb_csectors
* 512, addend
);
1660 /* compressed clusters are never modified */
1664 refcount
= update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, addend
);
1666 refcount
= get_refcount(bs
, offset
>> s
->cluster_bits
);
1670 if (refcount
== 1) {
1671 offset
|= QCOW_OFLAG_COPIED
;
1673 if (offset
!= old_offset
) {
1674 l2_table
[j
] = cpu_to_be64(offset
);
1680 if (bdrv_pwrite(s
->hd
,
1681 l2_offset
, l2_table
, l2_size
) != l2_size
)
1686 refcount
= update_cluster_refcount(bs
, l2_offset
>> s
->cluster_bits
, addend
);
1688 refcount
= get_refcount(bs
, l2_offset
>> s
->cluster_bits
);
1690 if (refcount
== 1) {
1691 l2_offset
|= QCOW_OFLAG_COPIED
;
1693 if (l2_offset
!= old_l2_offset
) {
1694 l1_table
[i
] = l2_offset
;
1700 for(i
= 0; i
< l1_size
; i
++)
1701 cpu_to_be64s(&l1_table
[i
]);
1702 if (bdrv_pwrite(s
->hd
, l1_table_offset
, l1_table
,
1703 l1_size2
) != l1_size2
)
1705 for(i
= 0; i
< l1_size
; i
++)
1706 be64_to_cpus(&l1_table
[i
]);
1709 qemu_free(l1_table
);
1710 qemu_free(l2_table
);
1714 qemu_free(l1_table
);
1715 qemu_free(l2_table
);
1719 static void qcow_free_snapshots(BlockDriverState
*bs
)
1721 BDRVQcowState
*s
= bs
->opaque
;
1724 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1725 qemu_free(s
->snapshots
[i
].name
);
1726 qemu_free(s
->snapshots
[i
].id_str
);
1728 qemu_free(s
->snapshots
);
1729 s
->snapshots
= NULL
;
1730 s
->nb_snapshots
= 0;
1733 static int qcow_read_snapshots(BlockDriverState
*bs
)
1735 BDRVQcowState
*s
= bs
->opaque
;
1736 QCowSnapshotHeader h
;
1738 int i
, id_str_size
, name_size
;
1740 uint32_t extra_data_size
;
1742 offset
= s
->snapshots_offset
;
1743 s
->snapshots
= qemu_mallocz(s
->nb_snapshots
* sizeof(QCowSnapshot
));
1746 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1747 offset
= align_offset(offset
, 8);
1748 if (bdrv_pread(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1750 offset
+= sizeof(h
);
1751 sn
= s
->snapshots
+ i
;
1752 sn
->l1_table_offset
= be64_to_cpu(h
.l1_table_offset
);
1753 sn
->l1_size
= be32_to_cpu(h
.l1_size
);
1754 sn
->vm_state_size
= be32_to_cpu(h
.vm_state_size
);
1755 sn
->date_sec
= be32_to_cpu(h
.date_sec
);
1756 sn
->date_nsec
= be32_to_cpu(h
.date_nsec
);
1757 sn
->vm_clock_nsec
= be64_to_cpu(h
.vm_clock_nsec
);
1758 extra_data_size
= be32_to_cpu(h
.extra_data_size
);
1760 id_str_size
= be16_to_cpu(h
.id_str_size
);
1761 name_size
= be16_to_cpu(h
.name_size
);
1763 offset
+= extra_data_size
;
1765 sn
->id_str
= qemu_malloc(id_str_size
+ 1);
1768 if (bdrv_pread(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1770 offset
+= id_str_size
;
1771 sn
->id_str
[id_str_size
] = '\0';
1773 sn
->name
= qemu_malloc(name_size
+ 1);
1776 if (bdrv_pread(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1778 offset
+= name_size
;
1779 sn
->name
[name_size
] = '\0';
1781 s
->snapshots_size
= offset
- s
->snapshots_offset
;
1784 qcow_free_snapshots(bs
);
1788 /* add at the end of the file a new list of snapshots */
1789 static int qcow_write_snapshots(BlockDriverState
*bs
)
1791 BDRVQcowState
*s
= bs
->opaque
;
1793 QCowSnapshotHeader h
;
1794 int i
, name_size
, id_str_size
, snapshots_size
;
1797 int64_t offset
, snapshots_offset
;
1799 /* compute the size of the snapshots */
1801 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1802 sn
= s
->snapshots
+ i
;
1803 offset
= align_offset(offset
, 8);
1804 offset
+= sizeof(h
);
1805 offset
+= strlen(sn
->id_str
);
1806 offset
+= strlen(sn
->name
);
1808 snapshots_size
= offset
;
1810 snapshots_offset
= alloc_clusters(bs
, snapshots_size
);
1811 offset
= snapshots_offset
;
1813 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1814 sn
= s
->snapshots
+ i
;
1815 memset(&h
, 0, sizeof(h
));
1816 h
.l1_table_offset
= cpu_to_be64(sn
->l1_table_offset
);
1817 h
.l1_size
= cpu_to_be32(sn
->l1_size
);
1818 h
.vm_state_size
= cpu_to_be32(sn
->vm_state_size
);
1819 h
.date_sec
= cpu_to_be32(sn
->date_sec
);
1820 h
.date_nsec
= cpu_to_be32(sn
->date_nsec
);
1821 h
.vm_clock_nsec
= cpu_to_be64(sn
->vm_clock_nsec
);
1823 id_str_size
= strlen(sn
->id_str
);
1824 name_size
= strlen(sn
->name
);
1825 h
.id_str_size
= cpu_to_be16(id_str_size
);
1826 h
.name_size
= cpu_to_be16(name_size
);
1827 offset
= align_offset(offset
, 8);
1828 if (bdrv_pwrite(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1830 offset
+= sizeof(h
);
1831 if (bdrv_pwrite(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1833 offset
+= id_str_size
;
1834 if (bdrv_pwrite(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1836 offset
+= name_size
;
1839 /* update the various header fields */
1840 data64
= cpu_to_be64(snapshots_offset
);
1841 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, snapshots_offset
),
1842 &data64
, sizeof(data64
)) != sizeof(data64
))
1844 data32
= cpu_to_be32(s
->nb_snapshots
);
1845 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, nb_snapshots
),
1846 &data32
, sizeof(data32
)) != sizeof(data32
))
1849 /* free the old snapshot table */
1850 free_clusters(bs
, s
->snapshots_offset
, s
->snapshots_size
);
1851 s
->snapshots_offset
= snapshots_offset
;
1852 s
->snapshots_size
= snapshots_size
;
1858 static void find_new_snapshot_id(BlockDriverState
*bs
,
1859 char *id_str
, int id_str_size
)
1861 BDRVQcowState
*s
= bs
->opaque
;
1863 int i
, id
, id_max
= 0;
1865 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1866 sn
= s
->snapshots
+ i
;
1867 id
= strtoul(sn
->id_str
, NULL
, 10);
1871 snprintf(id_str
, id_str_size
, "%d", id_max
+ 1);
1874 static int find_snapshot_by_id(BlockDriverState
*bs
, const char *id_str
)
1876 BDRVQcowState
*s
= bs
->opaque
;
1879 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1880 if (!strcmp(s
->snapshots
[i
].id_str
, id_str
))
1886 static int find_snapshot_by_id_or_name(BlockDriverState
*bs
, const char *name
)
1888 BDRVQcowState
*s
= bs
->opaque
;
1891 ret
= find_snapshot_by_id(bs
, name
);
1894 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1895 if (!strcmp(s
->snapshots
[i
].name
, name
))
1901 /* if no id is provided, a new one is constructed */
1902 static int qcow_snapshot_create(BlockDriverState
*bs
,
1903 QEMUSnapshotInfo
*sn_info
)
1905 BDRVQcowState
*s
= bs
->opaque
;
1906 QCowSnapshot
*snapshots1
, sn1
, *sn
= &sn1
;
1908 uint64_t *l1_table
= NULL
;
1910 memset(sn
, 0, sizeof(*sn
));
1912 if (sn_info
->id_str
[0] == '\0') {
1913 /* compute a new id */
1914 find_new_snapshot_id(bs
, sn_info
->id_str
, sizeof(sn_info
->id_str
));
1917 /* check that the ID is unique */
1918 if (find_snapshot_by_id(bs
, sn_info
->id_str
) >= 0)
1921 sn
->id_str
= qemu_strdup(sn_info
->id_str
);
1924 sn
->name
= qemu_strdup(sn_info
->name
);
1927 sn
->vm_state_size
= sn_info
->vm_state_size
;
1928 sn
->date_sec
= sn_info
->date_sec
;
1929 sn
->date_nsec
= sn_info
->date_nsec
;
1930 sn
->vm_clock_nsec
= sn_info
->vm_clock_nsec
;
1932 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1);
1936 /* create the L1 table of the snapshot */
1937 sn
->l1_table_offset
= alloc_clusters(bs
, s
->l1_size
* sizeof(uint64_t));
1938 sn
->l1_size
= s
->l1_size
;
1940 l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
1943 for(i
= 0; i
< s
->l1_size
; i
++) {
1944 l1_table
[i
] = cpu_to_be64(s
->l1_table
[i
]);
1946 if (bdrv_pwrite(s
->hd
, sn
->l1_table_offset
,
1947 l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
1948 (s
->l1_size
* sizeof(uint64_t)))
1950 qemu_free(l1_table
);
1953 snapshots1
= qemu_malloc((s
->nb_snapshots
+ 1) * sizeof(QCowSnapshot
));
1956 memcpy(snapshots1
, s
->snapshots
, s
->nb_snapshots
* sizeof(QCowSnapshot
));
1957 s
->snapshots
= snapshots1
;
1958 s
->snapshots
[s
->nb_snapshots
++] = *sn
;
1960 if (qcow_write_snapshots(bs
) < 0)
1963 check_refcounts(bs
);
1967 qemu_free(sn
->name
);
1968 qemu_free(l1_table
);
1972 /* copy the snapshot 'snapshot_name' into the current disk image */
1973 static int qcow_snapshot_goto(BlockDriverState
*bs
,
1974 const char *snapshot_id
)
1976 BDRVQcowState
*s
= bs
->opaque
;
1978 int i
, snapshot_index
, l1_size2
;
1980 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
1981 if (snapshot_index
< 0)
1983 sn
= &s
->snapshots
[snapshot_index
];
1985 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, -1) < 0)
1988 if (grow_l1_table(bs
, sn
->l1_size
) < 0)
1991 s
->l1_size
= sn
->l1_size
;
1992 l1_size2
= s
->l1_size
* sizeof(uint64_t);
1993 /* copy the snapshot l1 table to the current l1 table */
1994 if (bdrv_pread(s
->hd
, sn
->l1_table_offset
,
1995 s
->l1_table
, l1_size2
) != l1_size2
)
1997 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
,
1998 s
->l1_table
, l1_size2
) != l1_size2
)
2000 for(i
= 0;i
< s
->l1_size
; i
++) {
2001 be64_to_cpus(&s
->l1_table
[i
]);
2004 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1) < 0)
2008 check_refcounts(bs
);
2015 static int qcow_snapshot_delete(BlockDriverState
*bs
, const char *snapshot_id
)
2017 BDRVQcowState
*s
= bs
->opaque
;
2019 int snapshot_index
, ret
;
2021 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2022 if (snapshot_index
< 0)
2024 sn
= &s
->snapshots
[snapshot_index
];
2026 ret
= update_snapshot_refcount(bs
, sn
->l1_table_offset
, sn
->l1_size
, -1);
2029 /* must update the copied flag on the current cluster offsets */
2030 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 0);
2033 free_clusters(bs
, sn
->l1_table_offset
, sn
->l1_size
* sizeof(uint64_t));
2035 qemu_free(sn
->id_str
);
2036 qemu_free(sn
->name
);
2037 memmove(sn
, sn
+ 1, (s
->nb_snapshots
- snapshot_index
- 1) * sizeof(*sn
));
2039 ret
= qcow_write_snapshots(bs
);
2041 /* XXX: restore snapshot if error ? */
2045 check_refcounts(bs
);
2050 static int qcow_snapshot_list(BlockDriverState
*bs
,
2051 QEMUSnapshotInfo
**psn_tab
)
2053 BDRVQcowState
*s
= bs
->opaque
;
2054 QEMUSnapshotInfo
*sn_tab
, *sn_info
;
2058 sn_tab
= qemu_mallocz(s
->nb_snapshots
* sizeof(QEMUSnapshotInfo
));
2061 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2062 sn_info
= sn_tab
+ i
;
2063 sn
= s
->snapshots
+ i
;
2064 pstrcpy(sn_info
->id_str
, sizeof(sn_info
->id_str
),
2066 pstrcpy(sn_info
->name
, sizeof(sn_info
->name
),
2068 sn_info
->vm_state_size
= sn
->vm_state_size
;
2069 sn_info
->date_sec
= sn
->date_sec
;
2070 sn_info
->date_nsec
= sn
->date_nsec
;
2071 sn_info
->vm_clock_nsec
= sn
->vm_clock_nsec
;
2074 return s
->nb_snapshots
;
2081 /*********************************************************/
2082 /* refcount handling */
2084 static int refcount_init(BlockDriverState
*bs
)
2086 BDRVQcowState
*s
= bs
->opaque
;
2087 int ret
, refcount_table_size2
, i
;
2089 s
->refcount_block_cache
= qemu_malloc(s
->cluster_size
);
2090 if (!s
->refcount_block_cache
)
2092 refcount_table_size2
= s
->refcount_table_size
* sizeof(uint64_t);
2093 s
->refcount_table
= qemu_malloc(refcount_table_size2
);
2094 if (!s
->refcount_table
)
2096 if (s
->refcount_table_size
> 0) {
2097 ret
= bdrv_pread(s
->hd
, s
->refcount_table_offset
,
2098 s
->refcount_table
, refcount_table_size2
);
2099 if (ret
!= refcount_table_size2
)
2101 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2102 be64_to_cpus(&s
->refcount_table
[i
]);
2109 static void refcount_close(BlockDriverState
*bs
)
2111 BDRVQcowState
*s
= bs
->opaque
;
2112 qemu_free(s
->refcount_block_cache
);
2113 qemu_free(s
->refcount_table
);
2117 static int load_refcount_block(BlockDriverState
*bs
,
2118 int64_t refcount_block_offset
)
2120 BDRVQcowState
*s
= bs
->opaque
;
2122 ret
= bdrv_pread(s
->hd
, refcount_block_offset
, s
->refcount_block_cache
,
2124 if (ret
!= s
->cluster_size
)
2126 s
->refcount_block_cache_offset
= refcount_block_offset
;
2130 static int get_refcount(BlockDriverState
*bs
, int64_t cluster_index
)
2132 BDRVQcowState
*s
= bs
->opaque
;
2133 int refcount_table_index
, block_index
;
2134 int64_t refcount_block_offset
;
2136 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2137 if (refcount_table_index
>= s
->refcount_table_size
)
2139 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2140 if (!refcount_block_offset
)
2142 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2143 /* better than nothing: return allocated if read error */
2144 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2147 block_index
= cluster_index
&
2148 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2149 return be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2152 /* return < 0 if error */
2153 static int64_t alloc_clusters_noref(BlockDriverState
*bs
, int64_t size
)
2155 BDRVQcowState
*s
= bs
->opaque
;
2158 nb_clusters
= (size
+ s
->cluster_size
- 1) >> s
->cluster_bits
;
2160 if (get_refcount(bs
, s
->free_cluster_index
) == 0) {
2161 s
->free_cluster_index
++;
2162 for(i
= 1; i
< nb_clusters
; i
++) {
2163 if (get_refcount(bs
, s
->free_cluster_index
) != 0)
2165 s
->free_cluster_index
++;
2168 printf("alloc_clusters: size=%lld -> %lld\n",
2170 (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
);
2172 return (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
;
2175 s
->free_cluster_index
++;
2180 static int64_t alloc_clusters(BlockDriverState
*bs
, int64_t size
)
2184 offset
= alloc_clusters_noref(bs
, size
);
2185 update_refcount(bs
, offset
, size
, 1);
2189 /* only used to allocate compressed sectors. We try to allocate
2190 contiguous sectors. size must be <= cluster_size */
2191 static int64_t alloc_bytes(BlockDriverState
*bs
, int size
)
2193 BDRVQcowState
*s
= bs
->opaque
;
2194 int64_t offset
, cluster_offset
;
2195 int free_in_cluster
;
2197 assert(size
> 0 && size
<= s
->cluster_size
);
2198 if (s
->free_byte_offset
== 0) {
2199 s
->free_byte_offset
= alloc_clusters(bs
, s
->cluster_size
);
2202 free_in_cluster
= s
->cluster_size
-
2203 (s
->free_byte_offset
& (s
->cluster_size
- 1));
2204 if (size
<= free_in_cluster
) {
2205 /* enough space in current cluster */
2206 offset
= s
->free_byte_offset
;
2207 s
->free_byte_offset
+= size
;
2208 free_in_cluster
-= size
;
2209 if (free_in_cluster
== 0)
2210 s
->free_byte_offset
= 0;
2211 if ((offset
& (s
->cluster_size
- 1)) != 0)
2212 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2214 offset
= alloc_clusters(bs
, s
->cluster_size
);
2215 cluster_offset
= s
->free_byte_offset
& ~(s
->cluster_size
- 1);
2216 if ((cluster_offset
+ s
->cluster_size
) == offset
) {
2217 /* we are lucky: contiguous data */
2218 offset
= s
->free_byte_offset
;
2219 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2220 s
->free_byte_offset
+= size
;
2222 s
->free_byte_offset
= offset
;
2229 static void free_clusters(BlockDriverState
*bs
,
2230 int64_t offset
, int64_t size
)
2232 update_refcount(bs
, offset
, size
, -1);
2235 static int grow_refcount_table(BlockDriverState
*bs
, int min_size
)
2237 BDRVQcowState
*s
= bs
->opaque
;
2238 int new_table_size
, new_table_size2
, refcount_table_clusters
, i
, ret
;
2239 uint64_t *new_table
;
2240 int64_t table_offset
;
2244 int64_t old_table_offset
;
2246 if (min_size
<= s
->refcount_table_size
)
2248 /* compute new table size */
2249 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
2251 if (refcount_table_clusters
== 0) {
2252 refcount_table_clusters
= 1;
2254 refcount_table_clusters
= (refcount_table_clusters
* 3 + 1) / 2;
2256 new_table_size
= refcount_table_clusters
<< (s
->cluster_bits
- 3);
2257 if (min_size
<= new_table_size
)
2261 printf("grow_refcount_table from %d to %d\n",
2262 s
->refcount_table_size
,
2265 new_table_size2
= new_table_size
* sizeof(uint64_t);
2266 new_table
= qemu_mallocz(new_table_size2
);
2269 memcpy(new_table
, s
->refcount_table
,
2270 s
->refcount_table_size
* sizeof(uint64_t));
2271 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2272 cpu_to_be64s(&new_table
[i
]);
2273 /* Note: we cannot update the refcount now to avoid recursion */
2274 table_offset
= alloc_clusters_noref(bs
, new_table_size2
);
2275 ret
= bdrv_pwrite(s
->hd
, table_offset
, new_table
, new_table_size2
);
2276 if (ret
!= new_table_size2
)
2278 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2279 be64_to_cpus(&new_table
[i
]);
2281 data64
= cpu_to_be64(table_offset
);
2282 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, refcount_table_offset
),
2283 &data64
, sizeof(data64
)) != sizeof(data64
))
2285 data32
= cpu_to_be32(refcount_table_clusters
);
2286 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, refcount_table_clusters
),
2287 &data32
, sizeof(data32
)) != sizeof(data32
))
2289 qemu_free(s
->refcount_table
);
2290 old_table_offset
= s
->refcount_table_offset
;
2291 old_table_size
= s
->refcount_table_size
;
2292 s
->refcount_table
= new_table
;
2293 s
->refcount_table_size
= new_table_size
;
2294 s
->refcount_table_offset
= table_offset
;
2296 update_refcount(bs
, table_offset
, new_table_size2
, 1);
2297 free_clusters(bs
, old_table_offset
, old_table_size
* sizeof(uint64_t));
2300 free_clusters(bs
, table_offset
, new_table_size2
);
2301 qemu_free(new_table
);
2305 /* addend must be 1 or -1 */
2306 /* XXX: cache several refcount block clusters ? */
2307 static int update_cluster_refcount(BlockDriverState
*bs
,
2308 int64_t cluster_index
,
2311 BDRVQcowState
*s
= bs
->opaque
;
2312 int64_t offset
, refcount_block_offset
;
2313 int ret
, refcount_table_index
, block_index
, refcount
;
2316 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2317 if (refcount_table_index
>= s
->refcount_table_size
) {
2320 ret
= grow_refcount_table(bs
, refcount_table_index
+ 1);
2324 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2325 if (!refcount_block_offset
) {
2328 /* create a new refcount block */
2329 /* Note: we cannot update the refcount now to avoid recursion */
2330 offset
= alloc_clusters_noref(bs
, s
->cluster_size
);
2331 memset(s
->refcount_block_cache
, 0, s
->cluster_size
);
2332 ret
= bdrv_pwrite(s
->hd
, offset
, s
->refcount_block_cache
, s
->cluster_size
);
2333 if (ret
!= s
->cluster_size
)
2335 s
->refcount_table
[refcount_table_index
] = offset
;
2336 data64
= cpu_to_be64(offset
);
2337 ret
= bdrv_pwrite(s
->hd
, s
->refcount_table_offset
+
2338 refcount_table_index
* sizeof(uint64_t),
2339 &data64
, sizeof(data64
));
2340 if (ret
!= sizeof(data64
))
2343 refcount_block_offset
= offset
;
2344 s
->refcount_block_cache_offset
= offset
;
2345 update_refcount(bs
, offset
, s
->cluster_size
, 1);
2347 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2348 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2352 /* we can update the count and save it */
2353 block_index
= cluster_index
&
2354 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2355 refcount
= be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2357 if (refcount
< 0 || refcount
> 0xffff)
2359 if (refcount
== 0 && cluster_index
< s
->free_cluster_index
) {
2360 s
->free_cluster_index
= cluster_index
;
2362 s
->refcount_block_cache
[block_index
] = cpu_to_be16(refcount
);
2363 if (bdrv_pwrite(s
->hd
,
2364 refcount_block_offset
+ (block_index
<< REFCOUNT_SHIFT
),
2365 &s
->refcount_block_cache
[block_index
], 2) != 2)
2370 static void update_refcount(BlockDriverState
*bs
,
2371 int64_t offset
, int64_t length
,
2374 BDRVQcowState
*s
= bs
->opaque
;
2375 int64_t start
, last
, cluster_offset
;
2378 printf("update_refcount: offset=%lld size=%lld addend=%d\n",
2379 offset
, length
, addend
);
2383 start
= offset
& ~(s
->cluster_size
- 1);
2384 last
= (offset
+ length
- 1) & ~(s
->cluster_size
- 1);
2385 for(cluster_offset
= start
; cluster_offset
<= last
;
2386 cluster_offset
+= s
->cluster_size
) {
2387 update_cluster_refcount(bs
, cluster_offset
>> s
->cluster_bits
, addend
);
2392 static void inc_refcounts(BlockDriverState
*bs
,
2393 uint16_t *refcount_table
,
2394 int refcount_table_size
,
2395 int64_t offset
, int64_t size
)
2397 BDRVQcowState
*s
= bs
->opaque
;
2398 int64_t start
, last
, cluster_offset
;
2404 start
= offset
& ~(s
->cluster_size
- 1);
2405 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
2406 for(cluster_offset
= start
; cluster_offset
<= last
;
2407 cluster_offset
+= s
->cluster_size
) {
2408 k
= cluster_offset
>> s
->cluster_bits
;
2409 if (k
< 0 || k
>= refcount_table_size
) {
2410 printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset
);
2412 if (++refcount_table
[k
] == 0) {
2413 printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset
);
2419 static int check_refcounts_l1(BlockDriverState
*bs
,
2420 uint16_t *refcount_table
,
2421 int refcount_table_size
,
2422 int64_t l1_table_offset
, int l1_size
,
2425 BDRVQcowState
*s
= bs
->opaque
;
2426 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
;
2427 int l2_size
, i
, j
, nb_csectors
, refcount
;
2430 l1_size2
= l1_size
* sizeof(uint64_t);
2432 inc_refcounts(bs
, refcount_table
, refcount_table_size
,
2433 l1_table_offset
, l1_size2
);
2435 l1_table
= qemu_malloc(l1_size2
);
2438 if (bdrv_pread(s
->hd
, l1_table_offset
,
2439 l1_table
, l1_size2
) != l1_size2
)
2441 for(i
= 0;i
< l1_size
; i
++)
2442 be64_to_cpus(&l1_table
[i
]);
2444 l2_size
= s
->l2_size
* sizeof(uint64_t);
2445 l2_table
= qemu_malloc(l2_size
);
2448 for(i
= 0; i
< l1_size
; i
++) {
2449 l2_offset
= l1_table
[i
];
2452 refcount
= get_refcount(bs
, (l2_offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2453 if ((refcount
== 1) != ((l2_offset
& QCOW_OFLAG_COPIED
) != 0)) {
2454 printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
2455 l2_offset
, refcount
);
2458 l2_offset
&= ~QCOW_OFLAG_COPIED
;
2459 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
2461 for(j
= 0; j
< s
->l2_size
; j
++) {
2462 offset
= be64_to_cpu(l2_table
[j
]);
2464 if (offset
& QCOW_OFLAG_COMPRESSED
) {
2465 if (offset
& QCOW_OFLAG_COPIED
) {
2466 printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
2467 offset
>> s
->cluster_bits
);
2468 offset
&= ~QCOW_OFLAG_COPIED
;
2470 nb_csectors
= ((offset
>> s
->csize_shift
) &
2472 offset
&= s
->cluster_offset_mask
;
2473 inc_refcounts(bs
, refcount_table
,
2474 refcount_table_size
,
2475 offset
& ~511, nb_csectors
* 512);
2478 refcount
= get_refcount(bs
, (offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2479 if ((refcount
== 1) != ((offset
& QCOW_OFLAG_COPIED
) != 0)) {
2480 printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
2484 offset
&= ~QCOW_OFLAG_COPIED
;
2485 inc_refcounts(bs
, refcount_table
,
2486 refcount_table_size
,
2487 offset
, s
->cluster_size
);
2491 inc_refcounts(bs
, refcount_table
,
2492 refcount_table_size
,
2497 qemu_free(l1_table
);
2498 qemu_free(l2_table
);
2501 printf("ERROR: I/O error in check_refcounts_l1\n");
2502 qemu_free(l1_table
);
2503 qemu_free(l2_table
);
2507 static void check_refcounts(BlockDriverState
*bs
)
2509 BDRVQcowState
*s
= bs
->opaque
;
2511 int nb_clusters
, refcount1
, refcount2
, i
;
2513 uint16_t *refcount_table
;
2515 size
= bdrv_getlength(s
->hd
);
2516 nb_clusters
= (size
+ s
->cluster_size
- 1) >> s
->cluster_bits
;
2517 refcount_table
= qemu_mallocz(nb_clusters
* sizeof(uint16_t));
2520 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2521 0, s
->cluster_size
);
2523 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2524 s
->l1_table_offset
, s
->l1_size
, 1);
2527 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2528 sn
= s
->snapshots
+ i
;
2529 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2530 sn
->l1_table_offset
, sn
->l1_size
, 0);
2532 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2533 s
->snapshots_offset
, s
->snapshots_size
);
2536 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2537 s
->refcount_table_offset
,
2538 s
->refcount_table_size
* sizeof(uint64_t));
2539 for(i
= 0; i
< s
->refcount_table_size
; i
++) {
2541 offset
= s
->refcount_table
[i
];
2543 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2544 offset
, s
->cluster_size
);
2548 /* compare ref counts */
2549 for(i
= 0; i
< nb_clusters
; i
++) {
2550 refcount1
= get_refcount(bs
, i
);
2551 refcount2
= refcount_table
[i
];
2552 if (refcount1
!= refcount2
)
2553 printf("ERROR cluster %d refcount=%d reference=%d\n",
2554 i
, refcount1
, refcount2
);
2557 qemu_free(refcount_table
);
2561 static void dump_refcounts(BlockDriverState
*bs
)
2563 BDRVQcowState
*s
= bs
->opaque
;
2564 int64_t nb_clusters
, k
, k1
, size
;
2567 size
= bdrv_getlength(s
->hd
);
2568 nb_clusters
= (size
+ s
->cluster_size
- 1) >> s
->cluster_bits
;
2569 for(k
= 0; k
< nb_clusters
;) {
2571 refcount
= get_refcount(bs
, k
);
2573 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
2575 printf("%lld: refcount=%d nb=%lld\n", k
, refcount
, k
- k1
);
2581 BlockDriver bdrv_qcow2
= {
2583 sizeof(BDRVQcowState
),
2595 .bdrv_aio_read
= qcow_aio_read
,
2596 .bdrv_aio_write
= qcow_aio_write
,
2597 .bdrv_aio_cancel
= qcow_aio_cancel
,
2598 .aiocb_size
= sizeof(QCowAIOCB
),
2599 .bdrv_write_compressed
= qcow_write_compressed
,
2601 .bdrv_snapshot_create
= qcow_snapshot_create
,
2602 .bdrv_snapshot_goto
= qcow_snapshot_goto
,
2603 .bdrv_snapshot_delete
= qcow_snapshot_delete
,
2604 .bdrv_snapshot_list
= qcow_snapshot_list
,
2605 .bdrv_get_info
= qcow_get_info
,