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 */
64 typedef struct QCowHeader
{
67 uint64_t backing_file_offset
;
68 uint32_t backing_file_size
;
69 uint32_t cluster_bits
;
70 uint64_t size
; /* in bytes */
71 uint32_t crypt_method
;
72 uint32_t l1_size
; /* XXX: save number of clusters instead ? */
73 uint64_t l1_table_offset
;
74 uint64_t refcount_table_offset
;
75 uint32_t refcount_table_clusters
;
76 uint32_t nb_snapshots
;
77 uint64_t snapshots_offset
;
80 typedef struct __attribute__((packed
)) QCowSnapshotHeader
{
81 /* header is 8 byte aligned */
82 uint64_t l1_table_offset
;
91 uint64_t vm_clock_nsec
;
93 uint32_t vm_state_size
;
94 uint32_t extra_data_size
; /* for extension */
95 /* extra data follows */
100 #define L2_CACHE_SIZE 16
102 typedef struct QCowSnapshot
{
103 uint64_t l1_table_offset
;
107 uint32_t vm_state_size
;
110 uint64_t vm_clock_nsec
;
113 typedef struct BDRVQcowState
{
114 BlockDriverState
*hd
;
121 int l1_vm_state_index
;
124 uint64_t cluster_offset_mask
;
125 uint64_t l1_table_offset
;
128 uint64_t l2_cache_offsets
[L2_CACHE_SIZE
];
129 uint32_t l2_cache_counts
[L2_CACHE_SIZE
];
130 uint8_t *cluster_cache
;
131 uint8_t *cluster_data
;
132 uint64_t cluster_cache_offset
;
134 uint64_t *refcount_table
;
135 uint64_t refcount_table_offset
;
136 uint32_t refcount_table_size
;
137 uint64_t refcount_block_cache_offset
;
138 uint16_t *refcount_block_cache
;
139 int64_t free_cluster_index
;
140 int64_t free_byte_offset
;
142 uint32_t crypt_method
; /* current crypt method, 0 if no key yet */
143 uint32_t crypt_method_header
;
144 AES_KEY aes_encrypt_key
;
145 AES_KEY aes_decrypt_key
;
147 int64_t highest_alloc
; /* highest cluester allocated (in clusters) */
149 uint64_t snapshots_offset
;
152 QCowSnapshot
*snapshots
;
155 static int decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
);
156 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
157 uint8_t *buf
, int nb_sectors
);
158 static int qcow_read_snapshots(BlockDriverState
*bs
);
159 static void qcow_free_snapshots(BlockDriverState
*bs
);
160 static int refcount_init(BlockDriverState
*bs
);
161 static void refcount_close(BlockDriverState
*bs
);
162 static int get_refcount(BlockDriverState
*bs
, int64_t cluster_index
);
163 static int update_cluster_refcount(BlockDriverState
*bs
,
164 int64_t cluster_index
,
166 static void update_refcount(BlockDriverState
*bs
,
167 int64_t offset
, int64_t length
,
169 static int64_t alloc_clusters(BlockDriverState
*bs
, int64_t size
);
170 static int64_t alloc_bytes(BlockDriverState
*bs
, int size
);
171 static void free_clusters(BlockDriverState
*bs
,
172 int64_t offset
, int64_t size
);
174 static void check_refcounts(BlockDriverState
*bs
);
176 static void scan_refcount(BlockDriverState
*bs
, int64_t *high
);
179 static int qcow_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
181 const QCowHeader
*cow_header
= (const void *)buf
;
183 if (buf_size
>= sizeof(QCowHeader
) &&
184 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
185 be32_to_cpu(cow_header
->version
) == QCOW_VERSION
)
191 static int qcow_open(BlockDriverState
*bs
, const char *filename
, int flags
)
193 BDRVQcowState
*s
= bs
->opaque
;
194 int len
, i
, shift
, ret
;
197 /* Performance is terrible right now with cache=writethrough due mainly
198 * to reference count updates. If the user does not explicitly specify
199 * a caching type, force to writeback caching.
201 if ((flags
& BDRV_O_CACHE_DEF
)) {
202 flags
|= BDRV_O_CACHE_WB
;
203 flags
&= ~BDRV_O_CACHE_DEF
;
205 ret
= bdrv_file_open(&s
->hd
, filename
, flags
);
208 if (bdrv_pread(s
->hd
, 0, &header
, sizeof(header
)) != sizeof(header
))
210 be32_to_cpus(&header
.magic
);
211 be32_to_cpus(&header
.version
);
212 be64_to_cpus(&header
.backing_file_offset
);
213 be32_to_cpus(&header
.backing_file_size
);
214 be64_to_cpus(&header
.size
);
215 be32_to_cpus(&header
.cluster_bits
);
216 be32_to_cpus(&header
.crypt_method
);
217 be64_to_cpus(&header
.l1_table_offset
);
218 be32_to_cpus(&header
.l1_size
);
219 be64_to_cpus(&header
.refcount_table_offset
);
220 be32_to_cpus(&header
.refcount_table_clusters
);
221 be64_to_cpus(&header
.snapshots_offset
);
222 be32_to_cpus(&header
.nb_snapshots
);
224 if (header
.magic
!= QCOW_MAGIC
|| header
.version
!= QCOW_VERSION
)
226 if (header
.size
<= 1 ||
227 header
.cluster_bits
< 9 ||
228 header
.cluster_bits
> 16)
230 if (header
.crypt_method
> QCOW_CRYPT_AES
)
232 s
->crypt_method_header
= header
.crypt_method
;
233 if (s
->crypt_method_header
)
235 s
->cluster_bits
= header
.cluster_bits
;
236 s
->cluster_size
= 1 << s
->cluster_bits
;
237 s
->cluster_sectors
= 1 << (s
->cluster_bits
- 9);
238 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
239 s
->l2_size
= 1 << s
->l2_bits
;
240 bs
->total_sectors
= header
.size
/ 512;
241 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
242 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
243 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
244 s
->refcount_table_offset
= header
.refcount_table_offset
;
245 s
->refcount_table_size
=
246 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
248 s
->snapshots_offset
= header
.snapshots_offset
;
249 s
->nb_snapshots
= header
.nb_snapshots
;
251 /* read the level 1 table */
252 s
->l1_size
= header
.l1_size
;
253 shift
= s
->cluster_bits
+ s
->l2_bits
;
254 s
->l1_vm_state_index
= (header
.size
+ (1LL << shift
) - 1) >> shift
;
255 /* the L1 table must contain at least enough entries to put
257 if (s
->l1_size
< s
->l1_vm_state_index
)
259 s
->l1_table_offset
= header
.l1_table_offset
;
260 s
->l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
261 if (bdrv_pread(s
->hd
, s
->l1_table_offset
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
262 s
->l1_size
* sizeof(uint64_t))
264 for(i
= 0;i
< s
->l1_size
; i
++) {
265 be64_to_cpus(&s
->l1_table
[i
]);
268 s
->l2_cache
= qemu_malloc(s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
269 s
->cluster_cache
= qemu_malloc(s
->cluster_size
);
270 /* one more sector for decompressed data alignment */
271 s
->cluster_data
= qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
273 s
->cluster_cache_offset
= -1;
275 if (refcount_init(bs
) < 0)
278 scan_refcount(bs
, &s
->highest_alloc
);
280 /* read the backing file name */
281 if (header
.backing_file_offset
!= 0) {
282 len
= header
.backing_file_size
;
285 if (bdrv_pread(s
->hd
, header
.backing_file_offset
, bs
->backing_file
, len
) != len
)
287 bs
->backing_file
[len
] = '\0';
289 if (qcow_read_snapshots(bs
) < 0)
298 qcow_free_snapshots(bs
);
300 qemu_free(s
->l1_table
);
301 qemu_free(s
->l2_cache
);
302 qemu_free(s
->cluster_cache
);
303 qemu_free(s
->cluster_data
);
308 static int qcow_set_key(BlockDriverState
*bs
, const char *key
)
310 BDRVQcowState
*s
= bs
->opaque
;
314 memset(keybuf
, 0, 16);
318 /* XXX: we could compress the chars to 7 bits to increase
320 for(i
= 0;i
< len
;i
++) {
323 s
->crypt_method
= s
->crypt_method_header
;
325 if (AES_set_encrypt_key(keybuf
, 128, &s
->aes_encrypt_key
) != 0)
327 if (AES_set_decrypt_key(keybuf
, 128, &s
->aes_decrypt_key
) != 0)
337 AES_encrypt(in
, tmp
, &s
->aes_encrypt_key
);
338 AES_decrypt(tmp
, out
, &s
->aes_decrypt_key
);
339 for(i
= 0; i
< 16; i
++)
340 printf(" %02x", tmp
[i
]);
342 for(i
= 0; i
< 16; i
++)
343 printf(" %02x", out
[i
]);
350 /* The crypt function is compatible with the linux cryptoloop
351 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
353 static void encrypt_sectors(BDRVQcowState
*s
, int64_t sector_num
,
354 uint8_t *out_buf
, const uint8_t *in_buf
,
355 int nb_sectors
, int enc
,
364 for(i
= 0; i
< nb_sectors
; i
++) {
365 ivec
.ll
[0] = cpu_to_le64(sector_num
);
367 AES_cbc_encrypt(in_buf
, out_buf
, 512, key
,
375 static int copy_sectors(BlockDriverState
*bs
, uint64_t start_sect
,
376 uint64_t cluster_offset
, int n_start
, int n_end
)
378 BDRVQcowState
*s
= bs
->opaque
;
384 ret
= qcow_read(bs
, start_sect
+ n_start
, s
->cluster_data
, n
);
387 if (s
->crypt_method
) {
388 encrypt_sectors(s
, start_sect
+ n_start
,
390 s
->cluster_data
, n
, 1,
391 &s
->aes_encrypt_key
);
393 ret
= bdrv_write(s
->hd
, (cluster_offset
>> 9) + n_start
,
400 static void l2_cache_reset(BlockDriverState
*bs
)
402 BDRVQcowState
*s
= bs
->opaque
;
404 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
405 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
406 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
409 static inline int l2_cache_new_entry(BlockDriverState
*bs
)
411 BDRVQcowState
*s
= bs
->opaque
;
415 /* find a new entry in the least used one */
417 min_count
= 0xffffffff;
418 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
419 if (s
->l2_cache_counts
[i
] < min_count
) {
420 min_count
= s
->l2_cache_counts
[i
];
427 static int64_t align_offset(int64_t offset
, int n
)
429 offset
= (offset
+ n
- 1) & ~(n
- 1);
433 static int grow_l1_table(BlockDriverState
*bs
, int min_size
)
435 BDRVQcowState
*s
= bs
->opaque
;
436 int new_l1_size
, new_l1_size2
, ret
, i
;
437 uint64_t *new_l1_table
;
438 uint64_t new_l1_table_offset
;
441 new_l1_size
= s
->l1_size
;
442 if (min_size
<= new_l1_size
)
444 while (min_size
> new_l1_size
) {
445 new_l1_size
= (new_l1_size
* 3 + 1) / 2;
448 printf("grow l1_table from %d to %d\n", s
->l1_size
, new_l1_size
);
451 new_l1_size2
= sizeof(uint64_t) * new_l1_size
;
452 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 cpu_to_be32w((uint32_t*)data
, new_l1_size
);
468 cpu_to_be64w((uint64_t*)(data
+ 4), new_l1_table_offset
);
469 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_size
), data
,
470 sizeof(data
)) != sizeof(data
))
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
;
479 qemu_free(s
->l1_table
);
486 * seek l2_offset in the l2_cache table
487 * if not found, return NULL,
489 * increments the l2 cache hit count of the entry,
490 * if counter overflow, divide by two all counters
491 * return the pointer to the l2 cache entry
495 static uint64_t *seek_l2_table(BDRVQcowState
*s
, uint64_t l2_offset
)
499 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
500 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
501 /* increment the hit count */
502 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
503 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
504 s
->l2_cache_counts
[j
] >>= 1;
507 return s
->l2_cache
+ (i
<< s
->l2_bits
);
516 * Loads a L2 table into memory. If the table is in the cache, the cache
517 * is used; otherwise the L2 table is loaded from the image file.
519 * Returns a pointer to the L2 table on success, or NULL if the read from
520 * the image file failed.
523 static uint64_t *l2_load(BlockDriverState
*bs
, uint64_t l2_offset
)
525 BDRVQcowState
*s
= bs
->opaque
;
529 /* seek if the table for the given offset is in the cache */
531 l2_table
= seek_l2_table(s
, l2_offset
);
532 if (l2_table
!= NULL
)
535 /* not found: load a new entry in the least used one */
537 min_index
= l2_cache_new_entry(bs
);
538 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
539 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
540 s
->l2_size
* sizeof(uint64_t))
542 s
->l2_cache_offsets
[min_index
] = l2_offset
;
543 s
->l2_cache_counts
[min_index
] = 1;
551 * Allocate a new l2 entry in the file. If l1_index points to an already
552 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
553 * table) copy the contents of the old L2 table into the newly allocated one.
554 * Otherwise the new table is initialized with zeros.
558 static uint64_t *l2_allocate(BlockDriverState
*bs
, int l1_index
)
560 BDRVQcowState
*s
= bs
->opaque
;
562 uint64_t old_l2_offset
, tmp
;
563 uint64_t *l2_table
, l2_offset
;
565 old_l2_offset
= s
->l1_table
[l1_index
];
567 /* allocate a new l2 entry */
569 l2_offset
= alloc_clusters(bs
, s
->l2_size
* sizeof(uint64_t));
571 /* update the L1 entry */
573 s
->l1_table
[l1_index
] = l2_offset
| QCOW_OFLAG_COPIED
;
575 tmp
= cpu_to_be64(l2_offset
| QCOW_OFLAG_COPIED
);
576 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
+ l1_index
* sizeof(tmp
),
577 &tmp
, sizeof(tmp
)) != sizeof(tmp
))
580 /* allocate a new entry in the l2 cache */
582 min_index
= l2_cache_new_entry(bs
);
583 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
585 if (old_l2_offset
== 0) {
586 /* if there was no old l2 table, clear the new table */
587 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
589 /* if there was an old l2 table, read it from the disk */
590 if (bdrv_pread(s
->hd
, old_l2_offset
,
591 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
592 s
->l2_size
* sizeof(uint64_t))
595 /* write the l2 table to the file */
596 if (bdrv_pwrite(s
->hd
, l2_offset
,
597 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
598 s
->l2_size
* sizeof(uint64_t))
601 /* update the l2 cache entry */
603 s
->l2_cache_offsets
[min_index
] = l2_offset
;
604 s
->l2_cache_counts
[min_index
] = 1;
609 static int size_to_clusters(BDRVQcowState
*s
, int64_t size
)
611 return (size
+ (s
->cluster_size
- 1)) >> s
->cluster_bits
;
614 static int count_contiguous_clusters(uint64_t nb_clusters
, int cluster_size
,
615 uint64_t *l2_table
, uint64_t start
, uint64_t mask
)
618 uint64_t offset
= be64_to_cpu(l2_table
[0]) & ~mask
;
623 for (i
= start
; i
< start
+ nb_clusters
; i
++)
624 if (offset
+ i
* cluster_size
!= (be64_to_cpu(l2_table
[i
]) & ~mask
))
630 static int count_contiguous_free_clusters(uint64_t nb_clusters
, uint64_t *l2_table
)
634 while(nb_clusters
-- && l2_table
[i
] == 0)
643 * For a given offset of the disk image, return cluster offset in
646 * on entry, *num is the number of contiguous clusters we'd like to
647 * access following offset.
649 * on exit, *num is the number of contiguous clusters we can read.
651 * Return 1, if the offset is found
652 * Return 0, otherwise.
656 static uint64_t get_cluster_offset(BlockDriverState
*bs
,
657 uint64_t offset
, int *num
)
659 BDRVQcowState
*s
= bs
->opaque
;
660 int l1_index
, l2_index
;
661 uint64_t l2_offset
, *l2_table
, cluster_offset
;
663 int index_in_cluster
, nb_available
, nb_needed
, nb_clusters
;
665 index_in_cluster
= (offset
>> 9) & (s
->cluster_sectors
- 1);
666 nb_needed
= *num
+ index_in_cluster
;
668 l1_bits
= s
->l2_bits
+ s
->cluster_bits
;
670 /* compute how many bytes there are between the offset and
671 * the end of the l1 entry
674 nb_available
= (1 << l1_bits
) - (offset
& ((1 << l1_bits
) - 1));
676 /* compute the number of available sectors */
678 nb_available
= (nb_available
>> 9) + index_in_cluster
;
682 /* seek the the l2 offset in the l1 table */
684 l1_index
= offset
>> l1_bits
;
685 if (l1_index
>= s
->l1_size
)
688 l2_offset
= s
->l1_table
[l1_index
];
690 /* seek the l2 table of the given l2 offset */
695 /* load the l2 table in memory */
697 l2_offset
&= ~QCOW_OFLAG_COPIED
;
698 l2_table
= l2_load(bs
, l2_offset
);
699 if (l2_table
== NULL
)
702 /* find the cluster offset for the given disk offset */
704 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
705 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
706 nb_clusters
= size_to_clusters(s
, nb_needed
<< 9);
708 if (!cluster_offset
) {
709 /* how many empty clusters ? */
710 c
= count_contiguous_free_clusters(nb_clusters
, &l2_table
[l2_index
]);
712 /* how many allocated clusters ? */
713 c
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
714 &l2_table
[l2_index
], 0, QCOW_OFLAG_COPIED
);
717 nb_available
= (c
* s
->cluster_sectors
);
719 if (nb_available
> nb_needed
)
720 nb_available
= nb_needed
;
722 *num
= nb_available
- index_in_cluster
;
724 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
730 * free clusters according to its type: compressed or not
734 static void free_any_clusters(BlockDriverState
*bs
,
735 uint64_t cluster_offset
, int nb_clusters
)
737 BDRVQcowState
*s
= bs
->opaque
;
739 /* free the cluster */
741 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
743 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) &
745 free_clusters(bs
, (cluster_offset
& s
->cluster_offset_mask
) & ~511,
750 free_clusters(bs
, cluster_offset
, nb_clusters
<< s
->cluster_bits
);
758 * for a given disk offset, load (and allocate if needed)
761 * the l2 table offset in the qcow2 file and the cluster index
762 * in the l2 table are given to the caller.
766 static int get_cluster_table(BlockDriverState
*bs
, uint64_t offset
,
767 uint64_t **new_l2_table
,
768 uint64_t *new_l2_offset
,
771 BDRVQcowState
*s
= bs
->opaque
;
772 int l1_index
, l2_index
, ret
;
773 uint64_t l2_offset
, *l2_table
;
775 /* seek the the l2 offset in the l1 table */
777 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
778 if (l1_index
>= s
->l1_size
) {
779 ret
= grow_l1_table(bs
, l1_index
+ 1);
783 l2_offset
= s
->l1_table
[l1_index
];
785 /* seek the l2 table of the given l2 offset */
787 if (l2_offset
& QCOW_OFLAG_COPIED
) {
788 /* load the l2 table in memory */
789 l2_offset
&= ~QCOW_OFLAG_COPIED
;
790 l2_table
= l2_load(bs
, l2_offset
);
791 if (l2_table
== NULL
)
795 free_clusters(bs
, l2_offset
, s
->l2_size
* sizeof(uint64_t));
796 l2_table
= l2_allocate(bs
, l1_index
);
797 if (l2_table
== NULL
)
799 l2_offset
= s
->l1_table
[l1_index
] & ~QCOW_OFLAG_COPIED
;
802 /* find the cluster offset for the given disk offset */
804 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
806 *new_l2_table
= l2_table
;
807 *new_l2_offset
= l2_offset
;
808 *new_l2_index
= l2_index
;
814 * alloc_compressed_cluster_offset
816 * For a given offset of the disk image, return cluster offset in
819 * If the offset is not found, allocate a new compressed cluster.
821 * Return the cluster offset if successful,
822 * Return 0, otherwise.
826 static uint64_t alloc_compressed_cluster_offset(BlockDriverState
*bs
,
830 BDRVQcowState
*s
= bs
->opaque
;
832 uint64_t l2_offset
, *l2_table
, cluster_offset
;
835 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
839 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
840 if (cluster_offset
& QCOW_OFLAG_COPIED
)
841 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
844 free_any_clusters(bs
, cluster_offset
, 1);
846 cluster_offset
= alloc_bytes(bs
, compressed_size
);
847 nb_csectors
= ((cluster_offset
+ compressed_size
- 1) >> 9) -
848 (cluster_offset
>> 9);
850 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
851 ((uint64_t)nb_csectors
<< s
->csize_shift
);
853 /* update L2 table */
855 /* compressed clusters never have the copied flag */
857 l2_table
[l2_index
] = cpu_to_be64(cluster_offset
);
858 if (bdrv_pwrite(s
->hd
,
859 l2_offset
+ l2_index
* sizeof(uint64_t),
861 sizeof(uint64_t)) != sizeof(uint64_t))
864 return cluster_offset
;
867 typedef struct QCowL2Meta
875 static int alloc_cluster_link_l2(BlockDriverState
*bs
, uint64_t cluster_offset
,
878 BDRVQcowState
*s
= bs
->opaque
;
879 int i
, j
= 0, l2_index
, ret
;
880 uint64_t *old_cluster
, start_sect
, l2_offset
, *l2_table
;
882 if (m
->nb_clusters
== 0)
885 old_cluster
= qemu_malloc(m
->nb_clusters
* sizeof(uint64_t));
887 /* copy content of unmodified sectors */
888 start_sect
= (m
->offset
& ~(s
->cluster_size
- 1)) >> 9;
890 ret
= copy_sectors(bs
, start_sect
, cluster_offset
, 0, m
->n_start
);
895 if (m
->nb_available
& (s
->cluster_sectors
- 1)) {
896 uint64_t end
= m
->nb_available
& ~(uint64_t)(s
->cluster_sectors
- 1);
897 ret
= copy_sectors(bs
, start_sect
+ end
, cluster_offset
+ (end
<< 9),
898 m
->nb_available
- end
, s
->cluster_sectors
);
904 /* update L2 table */
905 if (!get_cluster_table(bs
, m
->offset
, &l2_table
, &l2_offset
, &l2_index
))
908 for (i
= 0; i
< m
->nb_clusters
; i
++) {
909 if(l2_table
[l2_index
+ i
] != 0)
910 old_cluster
[j
++] = l2_table
[l2_index
+ i
];
912 l2_table
[l2_index
+ i
] = cpu_to_be64((cluster_offset
+
913 (i
<< s
->cluster_bits
)) | QCOW_OFLAG_COPIED
);
916 if (bdrv_pwrite(s
->hd
, l2_offset
+ l2_index
* sizeof(uint64_t),
917 l2_table
+ l2_index
, m
->nb_clusters
* sizeof(uint64_t)) !=
918 m
->nb_clusters
* sizeof(uint64_t))
921 for (i
= 0; i
< j
; i
++)
922 free_any_clusters(bs
, old_cluster
[i
], 1);
926 qemu_free(old_cluster
);
931 * alloc_cluster_offset
933 * For a given offset of the disk image, return cluster offset in
936 * If the offset is not found, allocate a new cluster.
938 * Return the cluster offset if successful,
939 * Return 0, otherwise.
943 static uint64_t alloc_cluster_offset(BlockDriverState
*bs
,
945 int n_start
, int n_end
,
946 int *num
, QCowL2Meta
*m
)
948 BDRVQcowState
*s
= bs
->opaque
;
950 uint64_t l2_offset
, *l2_table
, cluster_offset
;
951 int nb_clusters
, i
= 0;
953 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
957 nb_clusters
= size_to_clusters(s
, n_end
<< 9);
959 nb_clusters
= MIN(nb_clusters
, s
->l2_size
- l2_index
);
961 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
963 /* We keep all QCOW_OFLAG_COPIED clusters */
965 if (cluster_offset
& QCOW_OFLAG_COPIED
) {
966 nb_clusters
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
967 &l2_table
[l2_index
], 0, 0);
969 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
975 /* for the moment, multiple compressed clusters are not managed */
977 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
)
980 /* how many available clusters ? */
982 while (i
< nb_clusters
) {
983 i
+= count_contiguous_clusters(nb_clusters
- i
, s
->cluster_size
,
984 &l2_table
[l2_index
], i
, 0);
986 if(be64_to_cpu(l2_table
[l2_index
+ i
]))
989 i
+= count_contiguous_free_clusters(nb_clusters
- i
,
990 &l2_table
[l2_index
+ i
]);
992 cluster_offset
= be64_to_cpu(l2_table
[l2_index
+ i
]);
994 if ((cluster_offset
& QCOW_OFLAG_COPIED
) ||
995 (cluster_offset
& QCOW_OFLAG_COMPRESSED
))
1000 /* allocate a new cluster */
1002 cluster_offset
= alloc_clusters(bs
, nb_clusters
* s
->cluster_size
);
1004 /* save info needed for meta data update */
1006 m
->n_start
= n_start
;
1007 m
->nb_clusters
= nb_clusters
;
1010 m
->nb_available
= MIN(nb_clusters
<< (s
->cluster_bits
- 9), n_end
);
1012 *num
= m
->nb_available
- n_start
;
1014 return cluster_offset
;
1017 static int qcow_is_allocated(BlockDriverState
*bs
, int64_t sector_num
,
1018 int nb_sectors
, int *pnum
)
1020 uint64_t cluster_offset
;
1023 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, pnum
);
1025 return (cluster_offset
!= 0);
1028 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
1029 const uint8_t *buf
, int buf_size
)
1031 z_stream strm1
, *strm
= &strm1
;
1034 memset(strm
, 0, sizeof(*strm
));
1036 strm
->next_in
= (uint8_t *)buf
;
1037 strm
->avail_in
= buf_size
;
1038 strm
->next_out
= out_buf
;
1039 strm
->avail_out
= out_buf_size
;
1041 ret
= inflateInit2(strm
, -12);
1044 ret
= inflate(strm
, Z_FINISH
);
1045 out_len
= strm
->next_out
- out_buf
;
1046 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
1047 out_len
!= out_buf_size
) {
1055 static int decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
)
1057 int ret
, csize
, nb_csectors
, sector_offset
;
1060 coffset
= cluster_offset
& s
->cluster_offset_mask
;
1061 if (s
->cluster_cache_offset
!= coffset
) {
1062 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
1063 sector_offset
= coffset
& 511;
1064 csize
= nb_csectors
* 512 - sector_offset
;
1065 ret
= bdrv_read(s
->hd
, coffset
>> 9, s
->cluster_data
, nb_csectors
);
1069 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
1070 s
->cluster_data
+ sector_offset
, csize
) < 0) {
1073 s
->cluster_cache_offset
= coffset
;
1078 /* handle reading after the end of the backing file */
1079 static int backing_read1(BlockDriverState
*bs
,
1080 int64_t sector_num
, uint8_t *buf
, int nb_sectors
)
1083 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
1085 if (sector_num
>= bs
->total_sectors
)
1088 n1
= bs
->total_sectors
- sector_num
;
1089 memset(buf
+ n1
* 512, 0, 512 * (nb_sectors
- n1
));
1093 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
1094 uint8_t *buf
, int nb_sectors
)
1096 BDRVQcowState
*s
= bs
->opaque
;
1097 int ret
, index_in_cluster
, n
, n1
;
1098 uint64_t cluster_offset
;
1100 while (nb_sectors
> 0) {
1102 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, &n
);
1103 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1104 if (!cluster_offset
) {
1105 if (bs
->backing_hd
) {
1106 /* read from the base image */
1107 n1
= backing_read1(bs
->backing_hd
, sector_num
, buf
, n
);
1109 ret
= bdrv_read(bs
->backing_hd
, sector_num
, buf
, n1
);
1114 memset(buf
, 0, 512 * n
);
1116 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1117 if (decompress_cluster(s
, cluster_offset
) < 0)
1119 memcpy(buf
, s
->cluster_cache
+ index_in_cluster
* 512, 512 * n
);
1121 ret
= bdrv_pread(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1124 if (s
->crypt_method
) {
1125 encrypt_sectors(s
, sector_num
, buf
, buf
, n
, 0,
1126 &s
->aes_decrypt_key
);
1136 static int qcow_write(BlockDriverState
*bs
, int64_t sector_num
,
1137 const uint8_t *buf
, int nb_sectors
)
1139 BDRVQcowState
*s
= bs
->opaque
;
1140 int ret
, index_in_cluster
, n
;
1141 uint64_t cluster_offset
;
1145 while (nb_sectors
> 0) {
1146 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1147 n_end
= index_in_cluster
+ nb_sectors
;
1148 if (s
->crypt_method
&&
1149 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1150 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1151 cluster_offset
= alloc_cluster_offset(bs
, sector_num
<< 9,
1153 n_end
, &n
, &l2meta
);
1154 if (!cluster_offset
)
1156 if (s
->crypt_method
) {
1157 encrypt_sectors(s
, sector_num
, s
->cluster_data
, buf
, n
, 1,
1158 &s
->aes_encrypt_key
);
1159 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512,
1160 s
->cluster_data
, n
* 512);
1162 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1164 if (ret
!= n
* 512 || alloc_cluster_link_l2(bs
, cluster_offset
, &l2meta
) < 0) {
1165 free_any_clusters(bs
, cluster_offset
, l2meta
.nb_clusters
);
1172 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1176 typedef struct QCowAIOCB
{
1177 BlockDriverAIOCB common
;
1182 uint64_t cluster_offset
;
1183 uint8_t *cluster_data
;
1184 BlockDriverAIOCB
*hd_aiocb
;
1189 static void qcow_aio_read_cb(void *opaque
, int ret
);
1190 static void qcow_aio_read_bh(void *opaque
)
1192 QCowAIOCB
*acb
= opaque
;
1193 qemu_bh_delete(acb
->bh
);
1195 qcow_aio_read_cb(opaque
, 0);
1198 static int qcow_schedule_bh(QEMUBHFunc
*cb
, QCowAIOCB
*acb
)
1203 acb
->bh
= qemu_bh_new(cb
, acb
);
1207 qemu_bh_schedule(acb
->bh
);
1212 static void qcow_aio_read_cb(void *opaque
, int ret
)
1214 QCowAIOCB
*acb
= opaque
;
1215 BlockDriverState
*bs
= acb
->common
.bs
;
1216 BDRVQcowState
*s
= bs
->opaque
;
1217 int index_in_cluster
, n1
;
1219 acb
->hd_aiocb
= NULL
;
1222 acb
->common
.cb(acb
->common
.opaque
, ret
);
1223 qemu_aio_release(acb
);
1227 /* post process the read buffer */
1228 if (!acb
->cluster_offset
) {
1230 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1233 if (s
->crypt_method
) {
1234 encrypt_sectors(s
, acb
->sector_num
, acb
->buf
, acb
->buf
,
1236 &s
->aes_decrypt_key
);
1240 acb
->nb_sectors
-= acb
->n
;
1241 acb
->sector_num
+= acb
->n
;
1242 acb
->buf
+= acb
->n
* 512;
1244 if (acb
->nb_sectors
== 0) {
1245 /* request completed */
1246 acb
->common
.cb(acb
->common
.opaque
, 0);
1247 qemu_aio_release(acb
);
1251 /* prepare next AIO request */
1252 acb
->n
= acb
->nb_sectors
;
1253 acb
->cluster_offset
= get_cluster_offset(bs
, acb
->sector_num
<< 9, &acb
->n
);
1254 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1256 if (!acb
->cluster_offset
) {
1257 if (bs
->backing_hd
) {
1258 /* read from the base image */
1259 n1
= backing_read1(bs
->backing_hd
, acb
->sector_num
,
1262 acb
->hd_aiocb
= bdrv_aio_read(bs
->backing_hd
, acb
->sector_num
,
1263 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1264 if (acb
->hd_aiocb
== NULL
)
1267 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1272 /* Note: in this case, no need to wait */
1273 memset(acb
->buf
, 0, 512 * acb
->n
);
1274 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1278 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1279 /* add AIO support for compressed blocks ? */
1280 if (decompress_cluster(s
, acb
->cluster_offset
) < 0)
1283 s
->cluster_cache
+ index_in_cluster
* 512, 512 * acb
->n
);
1284 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1288 if ((acb
->cluster_offset
& 511) != 0) {
1292 acb
->hd_aiocb
= bdrv_aio_read(s
->hd
,
1293 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1294 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1295 if (acb
->hd_aiocb
== NULL
)
1300 static QCowAIOCB
*qcow_aio_setup(BlockDriverState
*bs
,
1301 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1302 BlockDriverCompletionFunc
*cb
, void *opaque
)
1306 acb
= qemu_aio_get(bs
, cb
, opaque
);
1309 acb
->hd_aiocb
= NULL
;
1310 acb
->sector_num
= sector_num
;
1312 acb
->nb_sectors
= nb_sectors
;
1314 acb
->cluster_offset
= 0;
1315 acb
->l2meta
.nb_clusters
= 0;
1319 static BlockDriverAIOCB
*qcow_aio_read(BlockDriverState
*bs
,
1320 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1321 BlockDriverCompletionFunc
*cb
, void *opaque
)
1325 acb
= qcow_aio_setup(bs
, sector_num
, buf
, nb_sectors
, cb
, opaque
);
1329 qcow_aio_read_cb(acb
, 0);
1330 return &acb
->common
;
1333 static void qcow_aio_write_cb(void *opaque
, int ret
)
1335 QCowAIOCB
*acb
= opaque
;
1336 BlockDriverState
*bs
= acb
->common
.bs
;
1337 BDRVQcowState
*s
= bs
->opaque
;
1338 int index_in_cluster
;
1339 const uint8_t *src_buf
;
1342 acb
->hd_aiocb
= NULL
;
1346 acb
->common
.cb(acb
->common
.opaque
, ret
);
1347 qemu_aio_release(acb
);
1351 if (alloc_cluster_link_l2(bs
, acb
->cluster_offset
, &acb
->l2meta
) < 0) {
1352 free_any_clusters(bs
, acb
->cluster_offset
, acb
->l2meta
.nb_clusters
);
1356 acb
->nb_sectors
-= acb
->n
;
1357 acb
->sector_num
+= acb
->n
;
1358 acb
->buf
+= acb
->n
* 512;
1360 if (acb
->nb_sectors
== 0) {
1361 /* request completed */
1362 acb
->common
.cb(acb
->common
.opaque
, 0);
1363 qemu_aio_release(acb
);
1367 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1368 n_end
= index_in_cluster
+ acb
->nb_sectors
;
1369 if (s
->crypt_method
&&
1370 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1371 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1373 acb
->cluster_offset
= alloc_cluster_offset(bs
, acb
->sector_num
<< 9,
1375 n_end
, &acb
->n
, &acb
->l2meta
);
1376 if (!acb
->cluster_offset
|| (acb
->cluster_offset
& 511) != 0) {
1380 if (s
->crypt_method
) {
1381 if (!acb
->cluster_data
) {
1382 acb
->cluster_data
= qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS
*
1385 encrypt_sectors(s
, acb
->sector_num
, acb
->cluster_data
, acb
->buf
,
1386 acb
->n
, 1, &s
->aes_encrypt_key
);
1387 src_buf
= acb
->cluster_data
;
1391 acb
->hd_aiocb
= bdrv_aio_write(s
->hd
,
1392 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1394 qcow_aio_write_cb
, acb
);
1395 if (acb
->hd_aiocb
== NULL
)
1399 static BlockDriverAIOCB
*qcow_aio_write(BlockDriverState
*bs
,
1400 int64_t sector_num
, const uint8_t *buf
, int nb_sectors
,
1401 BlockDriverCompletionFunc
*cb
, void *opaque
)
1403 BDRVQcowState
*s
= bs
->opaque
;
1406 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1408 acb
= qcow_aio_setup(bs
, sector_num
, (uint8_t*)buf
, nb_sectors
, cb
, opaque
);
1412 qcow_aio_write_cb(acb
, 0);
1413 return &acb
->common
;
1416 static void qcow_aio_cancel(BlockDriverAIOCB
*blockacb
)
1418 QCowAIOCB
*acb
= (QCowAIOCB
*)blockacb
;
1420 bdrv_aio_cancel(acb
->hd_aiocb
);
1421 qemu_aio_release(acb
);
1424 static void qcow_close(BlockDriverState
*bs
)
1426 BDRVQcowState
*s
= bs
->opaque
;
1427 qemu_free(s
->l1_table
);
1428 qemu_free(s
->l2_cache
);
1429 qemu_free(s
->cluster_cache
);
1430 qemu_free(s
->cluster_data
);
1435 /* XXX: use std qcow open function ? */
1436 typedef struct QCowCreateState
{
1439 uint16_t *refcount_block
;
1440 uint64_t *refcount_table
;
1441 int64_t l1_table_offset
;
1442 int64_t refcount_table_offset
;
1443 int64_t refcount_block_offset
;
1446 static void create_refcount_update(QCowCreateState
*s
,
1447 int64_t offset
, int64_t size
)
1450 int64_t start
, last
, cluster_offset
;
1453 start
= offset
& ~(s
->cluster_size
- 1);
1454 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
1455 for(cluster_offset
= start
; cluster_offset
<= last
;
1456 cluster_offset
+= s
->cluster_size
) {
1457 p
= &s
->refcount_block
[cluster_offset
>> s
->cluster_bits
];
1458 refcount
= be16_to_cpu(*p
);
1460 *p
= cpu_to_be16(refcount
);
1464 static int qcow_create(const char *filename
, int64_t total_size
,
1465 const char *backing_file
, int flags
)
1467 int fd
, header_size
, backing_filename_len
, l1_size
, i
, shift
, l2_bits
;
1469 uint64_t tmp
, offset
;
1470 QCowCreateState s1
, *s
= &s1
;
1472 memset(s
, 0, sizeof(*s
));
1474 fd
= open(filename
, O_WRONLY
| O_CREAT
| O_TRUNC
| O_BINARY
, 0644);
1477 memset(&header
, 0, sizeof(header
));
1478 header
.magic
= cpu_to_be32(QCOW_MAGIC
);
1479 header
.version
= cpu_to_be32(QCOW_VERSION
);
1480 header
.size
= cpu_to_be64(total_size
* 512);
1481 header_size
= sizeof(header
);
1482 backing_filename_len
= 0;
1484 header
.backing_file_offset
= cpu_to_be64(header_size
);
1485 backing_filename_len
= strlen(backing_file
);
1486 header
.backing_file_size
= cpu_to_be32(backing_filename_len
);
1487 header_size
+= backing_filename_len
;
1489 s
->cluster_bits
= 12; /* 4 KB clusters */
1490 s
->cluster_size
= 1 << s
->cluster_bits
;
1491 header
.cluster_bits
= cpu_to_be32(s
->cluster_bits
);
1492 header_size
= (header_size
+ 7) & ~7;
1493 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1494 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1496 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1498 l2_bits
= s
->cluster_bits
- 3;
1499 shift
= s
->cluster_bits
+ l2_bits
;
1500 l1_size
= (((total_size
* 512) + (1LL << shift
) - 1) >> shift
);
1501 offset
= align_offset(header_size
, s
->cluster_size
);
1502 s
->l1_table_offset
= offset
;
1503 header
.l1_table_offset
= cpu_to_be64(s
->l1_table_offset
);
1504 header
.l1_size
= cpu_to_be32(l1_size
);
1505 offset
+= align_offset(l1_size
* sizeof(uint64_t), s
->cluster_size
);
1507 s
->refcount_table
= qemu_mallocz(s
->cluster_size
);
1508 s
->refcount_block
= qemu_mallocz(s
->cluster_size
);
1510 s
->refcount_table_offset
= offset
;
1511 header
.refcount_table_offset
= cpu_to_be64(offset
);
1512 header
.refcount_table_clusters
= cpu_to_be32(1);
1513 offset
+= s
->cluster_size
;
1515 s
->refcount_table
[0] = cpu_to_be64(offset
);
1516 s
->refcount_block_offset
= offset
;
1517 offset
+= s
->cluster_size
;
1519 /* update refcounts */
1520 create_refcount_update(s
, 0, header_size
);
1521 create_refcount_update(s
, s
->l1_table_offset
, l1_size
* sizeof(uint64_t));
1522 create_refcount_update(s
, s
->refcount_table_offset
, s
->cluster_size
);
1523 create_refcount_update(s
, s
->refcount_block_offset
, s
->cluster_size
);
1525 /* write all the data */
1526 write(fd
, &header
, sizeof(header
));
1528 write(fd
, backing_file
, backing_filename_len
);
1530 lseek(fd
, s
->l1_table_offset
, SEEK_SET
);
1532 for(i
= 0;i
< l1_size
; i
++) {
1533 write(fd
, &tmp
, sizeof(tmp
));
1535 lseek(fd
, s
->refcount_table_offset
, SEEK_SET
);
1536 write(fd
, s
->refcount_table
, s
->cluster_size
);
1538 lseek(fd
, s
->refcount_block_offset
, SEEK_SET
);
1539 write(fd
, s
->refcount_block
, s
->cluster_size
);
1541 qemu_free(s
->refcount_table
);
1542 qemu_free(s
->refcount_block
);
1547 static int qcow_make_empty(BlockDriverState
*bs
)
1550 /* XXX: not correct */
1551 BDRVQcowState
*s
= bs
->opaque
;
1552 uint32_t l1_length
= s
->l1_size
* sizeof(uint64_t);
1555 memset(s
->l1_table
, 0, l1_length
);
1556 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
, s
->l1_table
, l1_length
) < 0)
1558 ret
= bdrv_truncate(s
->hd
, s
->l1_table_offset
+ l1_length
);
1567 /* XXX: put compressed sectors first, then all the cluster aligned
1568 tables to avoid losing bytes in alignment */
1569 static int qcow_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1570 const uint8_t *buf
, int nb_sectors
)
1572 BDRVQcowState
*s
= bs
->opaque
;
1576 uint64_t cluster_offset
;
1578 if (nb_sectors
== 0) {
1579 /* align end of file to a sector boundary to ease reading with
1580 sector based I/Os */
1581 cluster_offset
= bdrv_getlength(s
->hd
);
1582 cluster_offset
= (cluster_offset
+ 511) & ~511;
1583 bdrv_truncate(s
->hd
, cluster_offset
);
1587 if (nb_sectors
!= s
->cluster_sectors
)
1590 out_buf
= qemu_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
1592 /* best compression, small window, no zlib header */
1593 memset(&strm
, 0, sizeof(strm
));
1594 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1596 9, Z_DEFAULT_STRATEGY
);
1602 strm
.avail_in
= s
->cluster_size
;
1603 strm
.next_in
= (uint8_t *)buf
;
1604 strm
.avail_out
= s
->cluster_size
;
1605 strm
.next_out
= out_buf
;
1607 ret
= deflate(&strm
, Z_FINISH
);
1608 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1613 out_len
= strm
.next_out
- out_buf
;
1617 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1618 /* could not compress: write normal cluster */
1619 qcow_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
1621 cluster_offset
= alloc_compressed_cluster_offset(bs
, sector_num
<< 9,
1623 if (!cluster_offset
)
1625 cluster_offset
&= s
->cluster_offset_mask
;
1626 if (bdrv_pwrite(s
->hd
, cluster_offset
, out_buf
, out_len
) != out_len
) {
1636 static void qcow_flush(BlockDriverState
*bs
)
1638 BDRVQcowState
*s
= bs
->opaque
;
1642 static int qcow_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
1644 BDRVQcowState
*s
= bs
->opaque
;
1645 bdi
->cluster_size
= s
->cluster_size
;
1646 bdi
->vm_state_offset
= (int64_t)s
->l1_vm_state_index
<<
1647 (s
->cluster_bits
+ s
->l2_bits
);
1648 bdi
->highest_alloc
= s
->highest_alloc
<< s
->cluster_bits
;
1652 /*********************************************************/
1653 /* snapshot support */
1655 /* update the refcounts of snapshots and the copied flag */
1656 static int update_snapshot_refcount(BlockDriverState
*bs
,
1657 int64_t l1_table_offset
,
1661 BDRVQcowState
*s
= bs
->opaque
;
1662 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
, l1_allocated
;
1663 int64_t old_offset
, old_l2_offset
;
1664 int l2_size
, i
, j
, l1_modified
, l2_modified
, nb_csectors
, refcount
;
1670 l1_size2
= l1_size
* sizeof(uint64_t);
1672 if (l1_table_offset
!= s
->l1_table_offset
) {
1673 l1_table
= qemu_malloc(l1_size2
);
1675 if (bdrv_pread(s
->hd
, l1_table_offset
,
1676 l1_table
, l1_size2
) != l1_size2
)
1678 for(i
= 0;i
< l1_size
; i
++)
1679 be64_to_cpus(&l1_table
[i
]);
1681 assert(l1_size
== s
->l1_size
);
1682 l1_table
= s
->l1_table
;
1686 l2_size
= s
->l2_size
* sizeof(uint64_t);
1687 l2_table
= qemu_malloc(l2_size
);
1689 for(i
= 0; i
< l1_size
; i
++) {
1690 l2_offset
= l1_table
[i
];
1692 old_l2_offset
= l2_offset
;
1693 l2_offset
&= ~QCOW_OFLAG_COPIED
;
1695 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
1697 for(j
= 0; j
< s
->l2_size
; j
++) {
1698 offset
= be64_to_cpu(l2_table
[j
]);
1700 old_offset
= offset
;
1701 offset
&= ~QCOW_OFLAG_COPIED
;
1702 if (offset
& QCOW_OFLAG_COMPRESSED
) {
1703 nb_csectors
= ((offset
>> s
->csize_shift
) &
1706 update_refcount(bs
, (offset
& s
->cluster_offset_mask
) & ~511,
1707 nb_csectors
* 512, addend
);
1708 /* compressed clusters are never modified */
1712 refcount
= update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, addend
);
1714 refcount
= get_refcount(bs
, offset
>> s
->cluster_bits
);
1718 if (refcount
== 1) {
1719 offset
|= QCOW_OFLAG_COPIED
;
1721 if (offset
!= old_offset
) {
1722 l2_table
[j
] = cpu_to_be64(offset
);
1728 if (bdrv_pwrite(s
->hd
,
1729 l2_offset
, l2_table
, l2_size
) != l2_size
)
1734 refcount
= update_cluster_refcount(bs
, l2_offset
>> s
->cluster_bits
, addend
);
1736 refcount
= get_refcount(bs
, l2_offset
>> s
->cluster_bits
);
1738 if (refcount
== 1) {
1739 l2_offset
|= QCOW_OFLAG_COPIED
;
1741 if (l2_offset
!= old_l2_offset
) {
1742 l1_table
[i
] = l2_offset
;
1748 for(i
= 0; i
< l1_size
; i
++)
1749 cpu_to_be64s(&l1_table
[i
]);
1750 if (bdrv_pwrite(s
->hd
, l1_table_offset
, l1_table
,
1751 l1_size2
) != l1_size2
)
1753 for(i
= 0; i
< l1_size
; i
++)
1754 be64_to_cpus(&l1_table
[i
]);
1757 qemu_free(l1_table
);
1758 qemu_free(l2_table
);
1762 qemu_free(l1_table
);
1763 qemu_free(l2_table
);
1767 static void qcow_free_snapshots(BlockDriverState
*bs
)
1769 BDRVQcowState
*s
= bs
->opaque
;
1772 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1773 qemu_free(s
->snapshots
[i
].name
);
1774 qemu_free(s
->snapshots
[i
].id_str
);
1776 qemu_free(s
->snapshots
);
1777 s
->snapshots
= NULL
;
1778 s
->nb_snapshots
= 0;
1781 static int qcow_read_snapshots(BlockDriverState
*bs
)
1783 BDRVQcowState
*s
= bs
->opaque
;
1784 QCowSnapshotHeader h
;
1786 int i
, id_str_size
, name_size
;
1788 uint32_t extra_data_size
;
1790 if (!s
->nb_snapshots
) {
1791 s
->snapshots
= NULL
;
1792 s
->snapshots_size
= 0;
1796 offset
= s
->snapshots_offset
;
1797 s
->snapshots
= qemu_mallocz(s
->nb_snapshots
* sizeof(QCowSnapshot
));
1798 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1799 offset
= align_offset(offset
, 8);
1800 if (bdrv_pread(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1802 offset
+= sizeof(h
);
1803 sn
= s
->snapshots
+ i
;
1804 sn
->l1_table_offset
= be64_to_cpu(h
.l1_table_offset
);
1805 sn
->l1_size
= be32_to_cpu(h
.l1_size
);
1806 sn
->vm_state_size
= be32_to_cpu(h
.vm_state_size
);
1807 sn
->date_sec
= be32_to_cpu(h
.date_sec
);
1808 sn
->date_nsec
= be32_to_cpu(h
.date_nsec
);
1809 sn
->vm_clock_nsec
= be64_to_cpu(h
.vm_clock_nsec
);
1810 extra_data_size
= be32_to_cpu(h
.extra_data_size
);
1812 id_str_size
= be16_to_cpu(h
.id_str_size
);
1813 name_size
= be16_to_cpu(h
.name_size
);
1815 offset
+= extra_data_size
;
1817 sn
->id_str
= qemu_malloc(id_str_size
+ 1);
1818 if (bdrv_pread(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1820 offset
+= id_str_size
;
1821 sn
->id_str
[id_str_size
] = '\0';
1823 sn
->name
= qemu_malloc(name_size
+ 1);
1824 if (bdrv_pread(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1826 offset
+= name_size
;
1827 sn
->name
[name_size
] = '\0';
1829 s
->snapshots_size
= offset
- s
->snapshots_offset
;
1832 qcow_free_snapshots(bs
);
1836 /* add at the end of the file a new list of snapshots */
1837 static int qcow_write_snapshots(BlockDriverState
*bs
)
1839 BDRVQcowState
*s
= bs
->opaque
;
1841 QCowSnapshotHeader h
;
1842 int i
, name_size
, id_str_size
, snapshots_size
;
1845 int64_t offset
, snapshots_offset
;
1847 /* compute the size of the snapshots */
1849 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1850 sn
= s
->snapshots
+ i
;
1851 offset
= align_offset(offset
, 8);
1852 offset
+= sizeof(h
);
1853 offset
+= strlen(sn
->id_str
);
1854 offset
+= strlen(sn
->name
);
1856 snapshots_size
= offset
;
1858 snapshots_offset
= alloc_clusters(bs
, snapshots_size
);
1859 offset
= snapshots_offset
;
1861 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1862 sn
= s
->snapshots
+ i
;
1863 memset(&h
, 0, sizeof(h
));
1864 h
.l1_table_offset
= cpu_to_be64(sn
->l1_table_offset
);
1865 h
.l1_size
= cpu_to_be32(sn
->l1_size
);
1866 h
.vm_state_size
= cpu_to_be32(sn
->vm_state_size
);
1867 h
.date_sec
= cpu_to_be32(sn
->date_sec
);
1868 h
.date_nsec
= cpu_to_be32(sn
->date_nsec
);
1869 h
.vm_clock_nsec
= cpu_to_be64(sn
->vm_clock_nsec
);
1871 id_str_size
= strlen(sn
->id_str
);
1872 name_size
= strlen(sn
->name
);
1873 h
.id_str_size
= cpu_to_be16(id_str_size
);
1874 h
.name_size
= cpu_to_be16(name_size
);
1875 offset
= align_offset(offset
, 8);
1876 if (bdrv_pwrite(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1878 offset
+= sizeof(h
);
1879 if (bdrv_pwrite(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1881 offset
+= id_str_size
;
1882 if (bdrv_pwrite(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1884 offset
+= name_size
;
1887 /* update the various header fields */
1888 data64
= cpu_to_be64(snapshots_offset
);
1889 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, snapshots_offset
),
1890 &data64
, sizeof(data64
)) != sizeof(data64
))
1892 data32
= cpu_to_be32(s
->nb_snapshots
);
1893 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, nb_snapshots
),
1894 &data32
, sizeof(data32
)) != sizeof(data32
))
1897 /* free the old snapshot table */
1898 free_clusters(bs
, s
->snapshots_offset
, s
->snapshots_size
);
1899 s
->snapshots_offset
= snapshots_offset
;
1900 s
->snapshots_size
= snapshots_size
;
1906 static void find_new_snapshot_id(BlockDriverState
*bs
,
1907 char *id_str
, int id_str_size
)
1909 BDRVQcowState
*s
= bs
->opaque
;
1911 int i
, id
, id_max
= 0;
1913 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1914 sn
= s
->snapshots
+ i
;
1915 id
= strtoul(sn
->id_str
, NULL
, 10);
1919 snprintf(id_str
, id_str_size
, "%d", id_max
+ 1);
1922 static int find_snapshot_by_id(BlockDriverState
*bs
, const char *id_str
)
1924 BDRVQcowState
*s
= bs
->opaque
;
1927 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1928 if (!strcmp(s
->snapshots
[i
].id_str
, id_str
))
1934 static int find_snapshot_by_id_or_name(BlockDriverState
*bs
, const char *name
)
1936 BDRVQcowState
*s
= bs
->opaque
;
1939 ret
= find_snapshot_by_id(bs
, name
);
1942 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1943 if (!strcmp(s
->snapshots
[i
].name
, name
))
1949 /* if no id is provided, a new one is constructed */
1950 static int qcow_snapshot_create(BlockDriverState
*bs
,
1951 QEMUSnapshotInfo
*sn_info
)
1953 BDRVQcowState
*s
= bs
->opaque
;
1954 QCowSnapshot
*snapshots1
, sn1
, *sn
= &sn1
;
1956 uint64_t *l1_table
= NULL
;
1958 memset(sn
, 0, sizeof(*sn
));
1960 if (sn_info
->id_str
[0] == '\0') {
1961 /* compute a new id */
1962 find_new_snapshot_id(bs
, sn_info
->id_str
, sizeof(sn_info
->id_str
));
1965 /* check that the ID is unique */
1966 if (find_snapshot_by_id(bs
, sn_info
->id_str
) >= 0)
1969 sn
->id_str
= qemu_strdup(sn_info
->id_str
);
1972 sn
->name
= qemu_strdup(sn_info
->name
);
1975 sn
->vm_state_size
= sn_info
->vm_state_size
;
1976 sn
->date_sec
= sn_info
->date_sec
;
1977 sn
->date_nsec
= sn_info
->date_nsec
;
1978 sn
->vm_clock_nsec
= sn_info
->vm_clock_nsec
;
1980 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1);
1984 /* create the L1 table of the snapshot */
1985 sn
->l1_table_offset
= alloc_clusters(bs
, s
->l1_size
* sizeof(uint64_t));
1986 sn
->l1_size
= s
->l1_size
;
1988 l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
1989 for(i
= 0; i
< s
->l1_size
; i
++) {
1990 l1_table
[i
] = cpu_to_be64(s
->l1_table
[i
]);
1992 if (bdrv_pwrite(s
->hd
, sn
->l1_table_offset
,
1993 l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
1994 (s
->l1_size
* sizeof(uint64_t)))
1996 qemu_free(l1_table
);
1999 snapshots1
= qemu_malloc((s
->nb_snapshots
+ 1) * sizeof(QCowSnapshot
));
2001 memcpy(snapshots1
, s
->snapshots
, s
->nb_snapshots
* sizeof(QCowSnapshot
));
2002 qemu_free(s
->snapshots
);
2004 s
->snapshots
= snapshots1
;
2005 s
->snapshots
[s
->nb_snapshots
++] = *sn
;
2007 if (qcow_write_snapshots(bs
) < 0)
2010 check_refcounts(bs
);
2014 qemu_free(sn
->name
);
2015 qemu_free(l1_table
);
2019 /* copy the snapshot 'snapshot_name' into the current disk image */
2020 static int qcow_snapshot_goto(BlockDriverState
*bs
,
2021 const char *snapshot_id
)
2023 BDRVQcowState
*s
= bs
->opaque
;
2025 int i
, snapshot_index
, l1_size2
;
2027 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2028 if (snapshot_index
< 0)
2030 sn
= &s
->snapshots
[snapshot_index
];
2032 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, -1) < 0)
2035 if (grow_l1_table(bs
, sn
->l1_size
) < 0)
2038 s
->l1_size
= sn
->l1_size
;
2039 l1_size2
= s
->l1_size
* sizeof(uint64_t);
2040 /* copy the snapshot l1 table to the current l1 table */
2041 if (bdrv_pread(s
->hd
, sn
->l1_table_offset
,
2042 s
->l1_table
, l1_size2
) != l1_size2
)
2044 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
,
2045 s
->l1_table
, l1_size2
) != l1_size2
)
2047 for(i
= 0;i
< s
->l1_size
; i
++) {
2048 be64_to_cpus(&s
->l1_table
[i
]);
2051 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1) < 0)
2055 check_refcounts(bs
);
2062 static int qcow_snapshot_delete(BlockDriverState
*bs
, const char *snapshot_id
)
2064 BDRVQcowState
*s
= bs
->opaque
;
2066 int snapshot_index
, ret
;
2068 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2069 if (snapshot_index
< 0)
2071 sn
= &s
->snapshots
[snapshot_index
];
2073 ret
= update_snapshot_refcount(bs
, sn
->l1_table_offset
, sn
->l1_size
, -1);
2076 /* must update the copied flag on the current cluster offsets */
2077 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 0);
2080 free_clusters(bs
, sn
->l1_table_offset
, sn
->l1_size
* sizeof(uint64_t));
2082 qemu_free(sn
->id_str
);
2083 qemu_free(sn
->name
);
2084 memmove(sn
, sn
+ 1, (s
->nb_snapshots
- snapshot_index
- 1) * sizeof(*sn
));
2086 ret
= qcow_write_snapshots(bs
);
2088 /* XXX: restore snapshot if error ? */
2092 check_refcounts(bs
);
2097 static int qcow_snapshot_list(BlockDriverState
*bs
,
2098 QEMUSnapshotInfo
**psn_tab
)
2100 BDRVQcowState
*s
= bs
->opaque
;
2101 QEMUSnapshotInfo
*sn_tab
, *sn_info
;
2105 sn_tab
= qemu_mallocz(s
->nb_snapshots
* sizeof(QEMUSnapshotInfo
));
2106 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2107 sn_info
= sn_tab
+ i
;
2108 sn
= s
->snapshots
+ i
;
2109 pstrcpy(sn_info
->id_str
, sizeof(sn_info
->id_str
),
2111 pstrcpy(sn_info
->name
, sizeof(sn_info
->name
),
2113 sn_info
->vm_state_size
= sn
->vm_state_size
;
2114 sn_info
->date_sec
= sn
->date_sec
;
2115 sn_info
->date_nsec
= sn
->date_nsec
;
2116 sn_info
->vm_clock_nsec
= sn
->vm_clock_nsec
;
2119 return s
->nb_snapshots
;
2122 /*********************************************************/
2123 /* refcount handling */
2125 static int refcount_init(BlockDriverState
*bs
)
2127 BDRVQcowState
*s
= bs
->opaque
;
2128 int ret
, refcount_table_size2
, i
;
2130 s
->refcount_block_cache
= qemu_malloc(s
->cluster_size
);
2131 refcount_table_size2
= s
->refcount_table_size
* sizeof(uint64_t);
2132 s
->refcount_table
= qemu_malloc(refcount_table_size2
);
2133 if (s
->refcount_table_size
> 0) {
2134 ret
= bdrv_pread(s
->hd
, s
->refcount_table_offset
,
2135 s
->refcount_table
, refcount_table_size2
);
2136 if (ret
!= refcount_table_size2
)
2138 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2139 be64_to_cpus(&s
->refcount_table
[i
]);
2146 static void refcount_close(BlockDriverState
*bs
)
2148 BDRVQcowState
*s
= bs
->opaque
;
2149 qemu_free(s
->refcount_block_cache
);
2150 qemu_free(s
->refcount_table
);
2154 static int load_refcount_block(BlockDriverState
*bs
,
2155 int64_t refcount_block_offset
)
2157 BDRVQcowState
*s
= bs
->opaque
;
2159 ret
= bdrv_pread(s
->hd
, refcount_block_offset
, s
->refcount_block_cache
,
2161 if (ret
!= s
->cluster_size
)
2163 s
->refcount_block_cache_offset
= refcount_block_offset
;
2167 static void scan_refcount(BlockDriverState
*bs
, int64_t *high
)
2169 BDRVQcowState
*s
= bs
->opaque
;
2170 int64_t refcnt_index
, cluster_index
, cluster_end
, h
= 0;
2172 for (refcnt_index
=0; refcnt_index
< s
->refcount_table_size
; refcnt_index
++){
2173 if (s
->refcount_table
[refcnt_index
] == 0) {
2176 cluster_index
= refcnt_index
<< (s
->cluster_bits
- REFCOUNT_SHIFT
);
2177 cluster_end
= (refcnt_index
+ 1) << (s
->cluster_bits
- REFCOUNT_SHIFT
);
2178 for ( ; cluster_index
< cluster_end
; cluster_index
++) {
2179 if (get_refcount(bs
, cluster_index
) == 0)
2180 /* do nothing -- reserved for free counting */;
2190 static int get_refcount(BlockDriverState
*bs
, int64_t cluster_index
)
2192 BDRVQcowState
*s
= bs
->opaque
;
2193 int refcount_table_index
, block_index
;
2194 int64_t refcount_block_offset
;
2196 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2197 if (refcount_table_index
>= s
->refcount_table_size
)
2199 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2200 if (!refcount_block_offset
)
2202 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2203 /* better than nothing: return allocated if read error */
2204 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2207 block_index
= cluster_index
&
2208 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2209 return be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2212 /* return < 0 if error */
2213 static int64_t alloc_clusters_noref(BlockDriverState
*bs
, int64_t size
)
2215 BDRVQcowState
*s
= bs
->opaque
;
2218 nb_clusters
= size_to_clusters(s
, size
);
2220 for(i
= 0; i
< nb_clusters
; i
++) {
2221 int64_t i
= s
->free_cluster_index
++;
2222 if (get_refcount(bs
, i
) != 0)
2226 printf("alloc_clusters: size=%lld -> %lld\n",
2228 (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
);
2231 if (s
->highest_alloc
< s
->free_cluster_index
)
2232 s
->highest_alloc
= s
->free_cluster_index
;
2234 return (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
;
2237 static int64_t alloc_clusters(BlockDriverState
*bs
, int64_t size
)
2241 offset
= alloc_clusters_noref(bs
, size
);
2242 update_refcount(bs
, offset
, size
, 1);
2246 /* only used to allocate compressed sectors. We try to allocate
2247 contiguous sectors. size must be <= cluster_size */
2248 static int64_t alloc_bytes(BlockDriverState
*bs
, int size
)
2250 BDRVQcowState
*s
= bs
->opaque
;
2251 int64_t offset
, cluster_offset
;
2252 int free_in_cluster
;
2254 assert(size
> 0 && size
<= s
->cluster_size
);
2255 if (s
->free_byte_offset
== 0) {
2256 s
->free_byte_offset
= alloc_clusters(bs
, s
->cluster_size
);
2259 free_in_cluster
= s
->cluster_size
-
2260 (s
->free_byte_offset
& (s
->cluster_size
- 1));
2261 if (size
<= free_in_cluster
) {
2262 /* enough space in current cluster */
2263 offset
= s
->free_byte_offset
;
2264 s
->free_byte_offset
+= size
;
2265 free_in_cluster
-= size
;
2266 if (free_in_cluster
== 0)
2267 s
->free_byte_offset
= 0;
2268 if ((offset
& (s
->cluster_size
- 1)) != 0)
2269 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2271 offset
= alloc_clusters(bs
, s
->cluster_size
);
2272 cluster_offset
= s
->free_byte_offset
& ~(s
->cluster_size
- 1);
2273 if ((cluster_offset
+ s
->cluster_size
) == offset
) {
2274 /* we are lucky: contiguous data */
2275 offset
= s
->free_byte_offset
;
2276 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2277 s
->free_byte_offset
+= size
;
2279 s
->free_byte_offset
= offset
;
2286 static void free_clusters(BlockDriverState
*bs
,
2287 int64_t offset
, int64_t size
)
2289 update_refcount(bs
, offset
, size
, -1);
2292 static int grow_refcount_table(BlockDriverState
*bs
, int min_size
)
2294 BDRVQcowState
*s
= bs
->opaque
;
2295 int new_table_size
, new_table_size2
, refcount_table_clusters
, i
, ret
;
2296 uint64_t *new_table
;
2297 int64_t table_offset
;
2300 int64_t old_table_offset
;
2302 if (min_size
<= s
->refcount_table_size
)
2304 /* compute new table size */
2305 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
2307 if (refcount_table_clusters
== 0) {
2308 refcount_table_clusters
= 1;
2310 refcount_table_clusters
= (refcount_table_clusters
* 3 + 1) / 2;
2312 new_table_size
= refcount_table_clusters
<< (s
->cluster_bits
- 3);
2313 if (min_size
<= new_table_size
)
2317 printf("grow_refcount_table from %d to %d\n",
2318 s
->refcount_table_size
,
2321 new_table_size2
= new_table_size
* sizeof(uint64_t);
2322 new_table
= qemu_mallocz(new_table_size2
);
2323 memcpy(new_table
, s
->refcount_table
,
2324 s
->refcount_table_size
* sizeof(uint64_t));
2325 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2326 cpu_to_be64s(&new_table
[i
]);
2327 /* Note: we cannot update the refcount now to avoid recursion */
2328 table_offset
= alloc_clusters_noref(bs
, new_table_size2
);
2329 ret
= bdrv_pwrite(s
->hd
, table_offset
, new_table
, new_table_size2
);
2330 if (ret
!= new_table_size2
)
2332 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2333 be64_to_cpus(&new_table
[i
]);
2335 cpu_to_be64w((uint64_t*)data
, table_offset
);
2336 cpu_to_be32w((uint32_t*)(data
+ 8), refcount_table_clusters
);
2337 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, refcount_table_offset
),
2338 data
, sizeof(data
)) != sizeof(data
))
2340 qemu_free(s
->refcount_table
);
2341 old_table_offset
= s
->refcount_table_offset
;
2342 old_table_size
= s
->refcount_table_size
;
2343 s
->refcount_table
= new_table
;
2344 s
->refcount_table_size
= new_table_size
;
2345 s
->refcount_table_offset
= table_offset
;
2347 update_refcount(bs
, table_offset
, new_table_size2
, 1);
2348 free_clusters(bs
, old_table_offset
, old_table_size
* sizeof(uint64_t));
2351 free_clusters(bs
, table_offset
, new_table_size2
);
2352 qemu_free(new_table
);
2356 /* addend must be 1 or -1 */
2357 /* XXX: cache several refcount block clusters ? */
2358 static int update_cluster_refcount(BlockDriverState
*bs
,
2359 int64_t cluster_index
,
2362 BDRVQcowState
*s
= bs
->opaque
;
2363 int64_t offset
, refcount_block_offset
;
2364 int ret
, refcount_table_index
, block_index
, refcount
;
2367 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2368 if (refcount_table_index
>= s
->refcount_table_size
) {
2371 ret
= grow_refcount_table(bs
, refcount_table_index
+ 1);
2375 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2376 if (!refcount_block_offset
) {
2379 /* create a new refcount block */
2380 /* Note: we cannot update the refcount now to avoid recursion */
2381 offset
= alloc_clusters_noref(bs
, s
->cluster_size
);
2382 memset(s
->refcount_block_cache
, 0, s
->cluster_size
);
2383 ret
= bdrv_pwrite(s
->hd
, offset
, s
->refcount_block_cache
, s
->cluster_size
);
2384 if (ret
!= s
->cluster_size
)
2386 s
->refcount_table
[refcount_table_index
] = offset
;
2387 data64
= cpu_to_be64(offset
);
2388 ret
= bdrv_pwrite(s
->hd
, s
->refcount_table_offset
+
2389 refcount_table_index
* sizeof(uint64_t),
2390 &data64
, sizeof(data64
));
2391 if (ret
!= sizeof(data64
))
2394 refcount_block_offset
= offset
;
2395 s
->refcount_block_cache_offset
= offset
;
2396 update_refcount(bs
, offset
, s
->cluster_size
, 1);
2398 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2399 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2403 /* we can update the count and save it */
2404 block_index
= cluster_index
&
2405 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2406 refcount
= be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2408 if (refcount
< 0 || refcount
> 0xffff)
2410 if (refcount
== 0 && cluster_index
< s
->free_cluster_index
) {
2411 s
->free_cluster_index
= cluster_index
;
2413 s
->refcount_block_cache
[block_index
] = cpu_to_be16(refcount
);
2414 if (bdrv_pwrite(s
->hd
,
2415 refcount_block_offset
+ (block_index
<< REFCOUNT_SHIFT
),
2416 &s
->refcount_block_cache
[block_index
], 2) != 2)
2421 static void update_refcount(BlockDriverState
*bs
,
2422 int64_t offset
, int64_t length
,
2425 BDRVQcowState
*s
= bs
->opaque
;
2426 int64_t start
, last
, cluster_offset
;
2429 printf("update_refcount: offset=%lld size=%lld addend=%d\n",
2430 offset
, length
, addend
);
2434 start
= offset
& ~(s
->cluster_size
- 1);
2435 last
= (offset
+ length
- 1) & ~(s
->cluster_size
- 1);
2436 for(cluster_offset
= start
; cluster_offset
<= last
;
2437 cluster_offset
+= s
->cluster_size
) {
2438 update_cluster_refcount(bs
, cluster_offset
>> s
->cluster_bits
, addend
);
2443 static void inc_refcounts(BlockDriverState
*bs
,
2444 uint16_t *refcount_table
,
2445 int refcount_table_size
,
2446 int64_t offset
, int64_t size
)
2448 BDRVQcowState
*s
= bs
->opaque
;
2449 int64_t start
, last
, cluster_offset
;
2455 start
= offset
& ~(s
->cluster_size
- 1);
2456 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
2457 for(cluster_offset
= start
; cluster_offset
<= last
;
2458 cluster_offset
+= s
->cluster_size
) {
2459 k
= cluster_offset
>> s
->cluster_bits
;
2460 if (k
< 0 || k
>= refcount_table_size
) {
2461 printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset
);
2463 if (++refcount_table
[k
] == 0) {
2464 printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset
);
2470 static int check_refcounts_l1(BlockDriverState
*bs
,
2471 uint16_t *refcount_table
,
2472 int refcount_table_size
,
2473 int64_t l1_table_offset
, int l1_size
,
2476 BDRVQcowState
*s
= bs
->opaque
;
2477 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
;
2478 int l2_size
, i
, j
, nb_csectors
, refcount
;
2481 l1_size2
= l1_size
* sizeof(uint64_t);
2483 inc_refcounts(bs
, refcount_table
, refcount_table_size
,
2484 l1_table_offset
, l1_size2
);
2486 l1_table
= qemu_malloc(l1_size2
);
2487 if (bdrv_pread(s
->hd
, l1_table_offset
,
2488 l1_table
, l1_size2
) != l1_size2
)
2490 for(i
= 0;i
< l1_size
; i
++)
2491 be64_to_cpus(&l1_table
[i
]);
2493 l2_size
= s
->l2_size
* sizeof(uint64_t);
2494 l2_table
= qemu_malloc(l2_size
);
2495 for(i
= 0; i
< l1_size
; i
++) {
2496 l2_offset
= l1_table
[i
];
2499 refcount
= get_refcount(bs
, (l2_offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2500 if ((refcount
== 1) != ((l2_offset
& QCOW_OFLAG_COPIED
) != 0)) {
2501 printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
2502 l2_offset
, refcount
);
2505 l2_offset
&= ~QCOW_OFLAG_COPIED
;
2506 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
2508 for(j
= 0; j
< s
->l2_size
; j
++) {
2509 offset
= be64_to_cpu(l2_table
[j
]);
2511 if (offset
& QCOW_OFLAG_COMPRESSED
) {
2512 if (offset
& QCOW_OFLAG_COPIED
) {
2513 printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
2514 offset
>> s
->cluster_bits
);
2515 offset
&= ~QCOW_OFLAG_COPIED
;
2517 nb_csectors
= ((offset
>> s
->csize_shift
) &
2519 offset
&= s
->cluster_offset_mask
;
2520 inc_refcounts(bs
, refcount_table
,
2521 refcount_table_size
,
2522 offset
& ~511, nb_csectors
* 512);
2525 refcount
= get_refcount(bs
, (offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2526 if ((refcount
== 1) != ((offset
& QCOW_OFLAG_COPIED
) != 0)) {
2527 printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
2531 offset
&= ~QCOW_OFLAG_COPIED
;
2532 inc_refcounts(bs
, refcount_table
,
2533 refcount_table_size
,
2534 offset
, s
->cluster_size
);
2538 inc_refcounts(bs
, refcount_table
,
2539 refcount_table_size
,
2544 qemu_free(l1_table
);
2545 qemu_free(l2_table
);
2548 printf("ERROR: I/O error in check_refcounts_l1\n");
2549 qemu_free(l1_table
);
2550 qemu_free(l2_table
);
2554 static void check_refcounts(BlockDriverState
*bs
)
2556 BDRVQcowState
*s
= bs
->opaque
;
2558 int nb_clusters
, refcount1
, refcount2
, i
;
2560 uint16_t *refcount_table
;
2562 size
= bdrv_getlength(s
->hd
);
2563 nb_clusters
= size_to_clusters(s
, size
);
2564 refcount_table
= qemu_mallocz(nb_clusters
* sizeof(uint16_t));
2567 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2568 0, s
->cluster_size
);
2570 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2571 s
->l1_table_offset
, s
->l1_size
, 1);
2574 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2575 sn
= s
->snapshots
+ i
;
2576 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2577 sn
->l1_table_offset
, sn
->l1_size
, 0);
2579 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2580 s
->snapshots_offset
, s
->snapshots_size
);
2583 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2584 s
->refcount_table_offset
,
2585 s
->refcount_table_size
* sizeof(uint64_t));
2586 for(i
= 0; i
< s
->refcount_table_size
; i
++) {
2588 offset
= s
->refcount_table
[i
];
2590 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2591 offset
, s
->cluster_size
);
2595 /* compare ref counts */
2596 for(i
= 0; i
< nb_clusters
; i
++) {
2597 refcount1
= get_refcount(bs
, i
);
2598 refcount2
= refcount_table
[i
];
2599 if (refcount1
!= refcount2
)
2600 printf("ERROR cluster %d refcount=%d reference=%d\n",
2601 i
, refcount1
, refcount2
);
2604 qemu_free(refcount_table
);
2608 static void dump_refcounts(BlockDriverState
*bs
)
2610 BDRVQcowState
*s
= bs
->opaque
;
2611 int64_t nb_clusters
, k
, k1
, size
;
2614 size
= bdrv_getlength(s
->hd
);
2615 nb_clusters
= size_to_clusters(s
, size
);
2616 for(k
= 0; k
< nb_clusters
;) {
2618 refcount
= get_refcount(bs
, k
);
2620 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
2622 printf("%lld: refcount=%d nb=%lld\n", k
, refcount
, k
- k1
);
2628 BlockDriver bdrv_qcow2
= {
2629 .format_name
= "qcow2",
2630 .instance_size
= sizeof(BDRVQcowState
),
2631 .bdrv_probe
= qcow_probe
,
2632 .bdrv_open
= qcow_open
,
2633 .bdrv_close
= qcow_close
,
2634 .bdrv_create
= qcow_create
,
2635 .bdrv_flush
= qcow_flush
,
2636 .bdrv_is_allocated
= qcow_is_allocated
,
2637 .bdrv_set_key
= qcow_set_key
,
2638 .bdrv_make_empty
= qcow_make_empty
,
2640 .bdrv_aio_read
= qcow_aio_read
,
2641 .bdrv_aio_write
= qcow_aio_write
,
2642 .bdrv_aio_cancel
= qcow_aio_cancel
,
2643 .aiocb_size
= sizeof(QCowAIOCB
),
2644 .bdrv_write_compressed
= qcow_write_compressed
,
2646 .bdrv_snapshot_create
= qcow_snapshot_create
,
2647 .bdrv_snapshot_goto
= qcow_snapshot_goto
,
2648 .bdrv_snapshot_delete
= qcow_snapshot_delete
,
2649 .bdrv_snapshot_list
= qcow_snapshot_list
,
2650 .bdrv_get_info
= qcow_get_info
,