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) */
148 int64_t nc_free
; /* num of free clusters below highest_alloc */
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
);
177 static void scan_refcount(BlockDriverState
*bs
, int64_t *high
, int64_t *free
);
180 static int qcow_probe(const uint8_t *buf
, int buf_size
, const char *filename
)
182 const QCowHeader
*cow_header
= (const void *)buf
;
184 if (buf_size
>= sizeof(QCowHeader
) &&
185 be32_to_cpu(cow_header
->magic
) == QCOW_MAGIC
&&
186 be32_to_cpu(cow_header
->version
) == QCOW_VERSION
)
192 static int qcow_open(BlockDriverState
*bs
, const char *filename
, int flags
)
194 BDRVQcowState
*s
= bs
->opaque
;
195 int len
, i
, shift
, ret
;
198 /* Performance is terrible right now with cache=writethrough due mainly
199 * to reference count updates. If the user does not explicitly specify
200 * a caching type, force to writeback caching.
202 if ((flags
& BDRV_O_CACHE_DEF
)) {
203 flags
|= BDRV_O_CACHE_WB
;
204 flags
&= ~BDRV_O_CACHE_DEF
;
206 ret
= bdrv_file_open(&s
->hd
, filename
, flags
);
209 if (bdrv_pread(s
->hd
, 0, &header
, sizeof(header
)) != sizeof(header
))
211 be32_to_cpus(&header
.magic
);
212 be32_to_cpus(&header
.version
);
213 be64_to_cpus(&header
.backing_file_offset
);
214 be32_to_cpus(&header
.backing_file_size
);
215 be64_to_cpus(&header
.size
);
216 be32_to_cpus(&header
.cluster_bits
);
217 be32_to_cpus(&header
.crypt_method
);
218 be64_to_cpus(&header
.l1_table_offset
);
219 be32_to_cpus(&header
.l1_size
);
220 be64_to_cpus(&header
.refcount_table_offset
);
221 be32_to_cpus(&header
.refcount_table_clusters
);
222 be64_to_cpus(&header
.snapshots_offset
);
223 be32_to_cpus(&header
.nb_snapshots
);
225 if (header
.magic
!= QCOW_MAGIC
|| header
.version
!= QCOW_VERSION
)
227 if (header
.size
<= 1 ||
228 header
.cluster_bits
< 9 ||
229 header
.cluster_bits
> 16)
231 if (header
.crypt_method
> QCOW_CRYPT_AES
)
233 s
->crypt_method_header
= header
.crypt_method
;
234 if (s
->crypt_method_header
)
236 s
->cluster_bits
= header
.cluster_bits
;
237 s
->cluster_size
= 1 << s
->cluster_bits
;
238 s
->cluster_sectors
= 1 << (s
->cluster_bits
- 9);
239 s
->l2_bits
= s
->cluster_bits
- 3; /* L2 is always one cluster */
240 s
->l2_size
= 1 << s
->l2_bits
;
241 bs
->total_sectors
= header
.size
/ 512;
242 s
->csize_shift
= (62 - (s
->cluster_bits
- 8));
243 s
->csize_mask
= (1 << (s
->cluster_bits
- 8)) - 1;
244 s
->cluster_offset_mask
= (1LL << s
->csize_shift
) - 1;
245 s
->refcount_table_offset
= header
.refcount_table_offset
;
246 s
->refcount_table_size
=
247 header
.refcount_table_clusters
<< (s
->cluster_bits
- 3);
249 s
->snapshots_offset
= header
.snapshots_offset
;
250 s
->nb_snapshots
= header
.nb_snapshots
;
252 /* read the level 1 table */
253 s
->l1_size
= header
.l1_size
;
254 shift
= s
->cluster_bits
+ s
->l2_bits
;
255 s
->l1_vm_state_index
= (header
.size
+ (1LL << shift
) - 1) >> shift
;
256 /* the L1 table must contain at least enough entries to put
258 if (s
->l1_size
< s
->l1_vm_state_index
)
260 s
->l1_table_offset
= header
.l1_table_offset
;
261 s
->l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
262 if (bdrv_pread(s
->hd
, s
->l1_table_offset
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
263 s
->l1_size
* sizeof(uint64_t))
265 for(i
= 0;i
< s
->l1_size
; i
++) {
266 be64_to_cpus(&s
->l1_table
[i
]);
269 s
->l2_cache
= qemu_malloc(s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
270 s
->cluster_cache
= qemu_malloc(s
->cluster_size
);
271 /* one more sector for decompressed data alignment */
272 s
->cluster_data
= qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
274 s
->cluster_cache_offset
= -1;
276 if (refcount_init(bs
) < 0)
279 scan_refcount(bs
, &s
->highest_alloc
, &s
->nc_free
);
281 /* read the backing file name */
282 if (header
.backing_file_offset
!= 0) {
283 len
= header
.backing_file_size
;
286 if (bdrv_pread(s
->hd
, header
.backing_file_offset
, bs
->backing_file
, len
) != len
)
288 bs
->backing_file
[len
] = '\0';
290 if (qcow_read_snapshots(bs
) < 0)
299 qcow_free_snapshots(bs
);
301 qemu_free(s
->l1_table
);
302 qemu_free(s
->l2_cache
);
303 qemu_free(s
->cluster_cache
);
304 qemu_free(s
->cluster_data
);
309 static int qcow_set_key(BlockDriverState
*bs
, const char *key
)
311 BDRVQcowState
*s
= bs
->opaque
;
315 memset(keybuf
, 0, 16);
319 /* XXX: we could compress the chars to 7 bits to increase
321 for(i
= 0;i
< len
;i
++) {
324 s
->crypt_method
= s
->crypt_method_header
;
326 if (AES_set_encrypt_key(keybuf
, 128, &s
->aes_encrypt_key
) != 0)
328 if (AES_set_decrypt_key(keybuf
, 128, &s
->aes_decrypt_key
) != 0)
338 AES_encrypt(in
, tmp
, &s
->aes_encrypt_key
);
339 AES_decrypt(tmp
, out
, &s
->aes_decrypt_key
);
340 for(i
= 0; i
< 16; i
++)
341 printf(" %02x", tmp
[i
]);
343 for(i
= 0; i
< 16; i
++)
344 printf(" %02x", out
[i
]);
351 /* The crypt function is compatible with the linux cryptoloop
352 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
354 static void encrypt_sectors(BDRVQcowState
*s
, int64_t sector_num
,
355 uint8_t *out_buf
, const uint8_t *in_buf
,
356 int nb_sectors
, int enc
,
365 for(i
= 0; i
< nb_sectors
; i
++) {
366 ivec
.ll
[0] = cpu_to_le64(sector_num
);
368 AES_cbc_encrypt(in_buf
, out_buf
, 512, key
,
376 static int copy_sectors(BlockDriverState
*bs
, uint64_t start_sect
,
377 uint64_t cluster_offset
, int n_start
, int n_end
)
379 BDRVQcowState
*s
= bs
->opaque
;
385 ret
= qcow_read(bs
, start_sect
+ n_start
, s
->cluster_data
, n
);
388 if (s
->crypt_method
) {
389 encrypt_sectors(s
, start_sect
+ n_start
,
391 s
->cluster_data
, n
, 1,
392 &s
->aes_encrypt_key
);
394 ret
= bdrv_write(s
->hd
, (cluster_offset
>> 9) + n_start
,
401 static void l2_cache_reset(BlockDriverState
*bs
)
403 BDRVQcowState
*s
= bs
->opaque
;
405 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
406 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
407 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
410 static inline int l2_cache_new_entry(BlockDriverState
*bs
)
412 BDRVQcowState
*s
= bs
->opaque
;
416 /* find a new entry in the least used one */
418 min_count
= 0xffffffff;
419 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
420 if (s
->l2_cache_counts
[i
] < min_count
) {
421 min_count
= s
->l2_cache_counts
[i
];
428 static int64_t align_offset(int64_t offset
, int n
)
430 offset
= (offset
+ n
- 1) & ~(n
- 1);
434 static int grow_l1_table(BlockDriverState
*bs
, int min_size
)
436 BDRVQcowState
*s
= bs
->opaque
;
437 int new_l1_size
, new_l1_size2
, ret
, i
;
438 uint64_t *new_l1_table
;
439 uint64_t new_l1_table_offset
;
442 new_l1_size
= s
->l1_size
;
443 if (min_size
<= new_l1_size
)
445 while (min_size
> new_l1_size
) {
446 new_l1_size
= (new_l1_size
* 3 + 1) / 2;
449 printf("grow l1_table from %d to %d\n", s
->l1_size
, new_l1_size
);
452 new_l1_size2
= sizeof(uint64_t) * new_l1_size
;
453 new_l1_table
= qemu_mallocz(new_l1_size2
);
454 memcpy(new_l1_table
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t));
456 /* write new table (align to cluster) */
457 new_l1_table_offset
= alloc_clusters(bs
, new_l1_size2
);
459 for(i
= 0; i
< s
->l1_size
; i
++)
460 new_l1_table
[i
] = cpu_to_be64(new_l1_table
[i
]);
461 ret
= bdrv_pwrite(s
->hd
, new_l1_table_offset
, new_l1_table
, new_l1_size2
);
462 if (ret
!= new_l1_size2
)
464 for(i
= 0; i
< s
->l1_size
; i
++)
465 new_l1_table
[i
] = be64_to_cpu(new_l1_table
[i
]);
468 cpu_to_be32w((uint32_t*)data
, new_l1_size
);
469 cpu_to_be64w((uint64_t*)(data
+ 4), new_l1_table_offset
);
470 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_size
), data
,
471 sizeof(data
)) != sizeof(data
))
473 qemu_free(s
->l1_table
);
474 free_clusters(bs
, s
->l1_table_offset
, s
->l1_size
* sizeof(uint64_t));
475 s
->l1_table_offset
= new_l1_table_offset
;
476 s
->l1_table
= new_l1_table
;
477 s
->l1_size
= new_l1_size
;
480 qemu_free(s
->l1_table
);
487 * seek l2_offset in the l2_cache table
488 * if not found, return NULL,
490 * increments the l2 cache hit count of the entry,
491 * if counter overflow, divide by two all counters
492 * return the pointer to the l2 cache entry
496 static uint64_t *seek_l2_table(BDRVQcowState
*s
, uint64_t l2_offset
)
500 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
501 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
502 /* increment the hit count */
503 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
504 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
505 s
->l2_cache_counts
[j
] >>= 1;
508 return s
->l2_cache
+ (i
<< s
->l2_bits
);
517 * Loads a L2 table into memory. If the table is in the cache, the cache
518 * is used; otherwise the L2 table is loaded from the image file.
520 * Returns a pointer to the L2 table on success, or NULL if the read from
521 * the image file failed.
524 static uint64_t *l2_load(BlockDriverState
*bs
, uint64_t l2_offset
)
526 BDRVQcowState
*s
= bs
->opaque
;
530 /* seek if the table for the given offset is in the cache */
532 l2_table
= seek_l2_table(s
, l2_offset
);
533 if (l2_table
!= NULL
)
536 /* not found: load a new entry in the least used one */
538 min_index
= l2_cache_new_entry(bs
);
539 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
540 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
541 s
->l2_size
* sizeof(uint64_t))
543 s
->l2_cache_offsets
[min_index
] = l2_offset
;
544 s
->l2_cache_counts
[min_index
] = 1;
552 * Allocate a new l2 entry in the file. If l1_index points to an already
553 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
554 * table) copy the contents of the old L2 table into the newly allocated one.
555 * Otherwise the new table is initialized with zeros.
559 static uint64_t *l2_allocate(BlockDriverState
*bs
, int l1_index
)
561 BDRVQcowState
*s
= bs
->opaque
;
563 uint64_t old_l2_offset
, tmp
;
564 uint64_t *l2_table
, l2_offset
;
566 old_l2_offset
= s
->l1_table
[l1_index
];
568 /* allocate a new l2 entry */
570 l2_offset
= alloc_clusters(bs
, s
->l2_size
* sizeof(uint64_t));
572 /* update the L1 entry */
574 s
->l1_table
[l1_index
] = l2_offset
| QCOW_OFLAG_COPIED
;
576 tmp
= cpu_to_be64(l2_offset
| QCOW_OFLAG_COPIED
);
577 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
+ l1_index
* sizeof(tmp
),
578 &tmp
, sizeof(tmp
)) != sizeof(tmp
))
581 /* allocate a new entry in the l2 cache */
583 min_index
= l2_cache_new_entry(bs
);
584 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
586 if (old_l2_offset
== 0) {
587 /* if there was no old l2 table, clear the new table */
588 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
590 /* if there was an old l2 table, read it from the disk */
591 if (bdrv_pread(s
->hd
, old_l2_offset
,
592 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
593 s
->l2_size
* sizeof(uint64_t))
596 /* write the l2 table to the file */
597 if (bdrv_pwrite(s
->hd
, l2_offset
,
598 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
599 s
->l2_size
* sizeof(uint64_t))
602 /* update the l2 cache entry */
604 s
->l2_cache_offsets
[min_index
] = l2_offset
;
605 s
->l2_cache_counts
[min_index
] = 1;
610 static int size_to_clusters(BDRVQcowState
*s
, int64_t size
)
612 return (size
+ (s
->cluster_size
- 1)) >> s
->cluster_bits
;
615 static int count_contiguous_clusters(uint64_t nb_clusters
, int cluster_size
,
616 uint64_t *l2_table
, uint64_t start
, uint64_t mask
)
619 uint64_t offset
= be64_to_cpu(l2_table
[0]) & ~mask
;
624 for (i
= start
; i
< start
+ nb_clusters
; i
++)
625 if (offset
+ i
* cluster_size
!= (be64_to_cpu(l2_table
[i
]) & ~mask
))
631 static int count_contiguous_free_clusters(uint64_t nb_clusters
, uint64_t *l2_table
)
635 while(nb_clusters
-- && l2_table
[i
] == 0)
644 * For a given offset of the disk image, return cluster offset in
647 * on entry, *num is the number of contiguous clusters we'd like to
648 * access following offset.
650 * on exit, *num is the number of contiguous clusters we can read.
652 * Return 1, if the offset is found
653 * Return 0, otherwise.
657 static uint64_t get_cluster_offset(BlockDriverState
*bs
,
658 uint64_t offset
, int *num
)
660 BDRVQcowState
*s
= bs
->opaque
;
661 int l1_index
, l2_index
;
662 uint64_t l2_offset
, *l2_table
, cluster_offset
;
664 int index_in_cluster
, nb_available
, nb_needed
, nb_clusters
;
666 index_in_cluster
= (offset
>> 9) & (s
->cluster_sectors
- 1);
667 nb_needed
= *num
+ index_in_cluster
;
669 l1_bits
= s
->l2_bits
+ s
->cluster_bits
;
671 /* compute how many bytes there are between the offset and
672 * the end of the l1 entry
675 nb_available
= (1 << l1_bits
) - (offset
& ((1 << l1_bits
) - 1));
677 /* compute the number of available sectors */
679 nb_available
= (nb_available
>> 9) + index_in_cluster
;
683 /* seek the the l2 offset in the l1 table */
685 l1_index
= offset
>> l1_bits
;
686 if (l1_index
>= s
->l1_size
)
689 l2_offset
= s
->l1_table
[l1_index
];
691 /* seek the l2 table of the given l2 offset */
696 /* load the l2 table in memory */
698 l2_offset
&= ~QCOW_OFLAG_COPIED
;
699 l2_table
= l2_load(bs
, l2_offset
);
700 if (l2_table
== NULL
)
703 /* find the cluster offset for the given disk offset */
705 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
706 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
707 nb_clusters
= size_to_clusters(s
, nb_needed
<< 9);
709 if (!cluster_offset
) {
710 /* how many empty clusters ? */
711 c
= count_contiguous_free_clusters(nb_clusters
, &l2_table
[l2_index
]);
713 /* how many allocated clusters ? */
714 c
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
715 &l2_table
[l2_index
], 0, QCOW_OFLAG_COPIED
);
718 nb_available
= (c
* s
->cluster_sectors
);
720 if (nb_available
> nb_needed
)
721 nb_available
= nb_needed
;
723 *num
= nb_available
- index_in_cluster
;
725 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
731 * free clusters according to its type: compressed or not
735 static void free_any_clusters(BlockDriverState
*bs
,
736 uint64_t cluster_offset
, int nb_clusters
)
738 BDRVQcowState
*s
= bs
->opaque
;
740 /* free the cluster */
742 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
744 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) &
746 free_clusters(bs
, (cluster_offset
& s
->cluster_offset_mask
) & ~511,
751 free_clusters(bs
, cluster_offset
, nb_clusters
<< s
->cluster_bits
);
759 * for a given disk offset, load (and allocate if needed)
762 * the l2 table offset in the qcow2 file and the cluster index
763 * in the l2 table are given to the caller.
767 static int get_cluster_table(BlockDriverState
*bs
, uint64_t offset
,
768 uint64_t **new_l2_table
,
769 uint64_t *new_l2_offset
,
772 BDRVQcowState
*s
= bs
->opaque
;
773 int l1_index
, l2_index
, ret
;
774 uint64_t l2_offset
, *l2_table
;
776 /* seek the the l2 offset in the l1 table */
778 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
779 if (l1_index
>= s
->l1_size
) {
780 ret
= grow_l1_table(bs
, l1_index
+ 1);
784 l2_offset
= s
->l1_table
[l1_index
];
786 /* seek the l2 table of the given l2 offset */
788 if (l2_offset
& QCOW_OFLAG_COPIED
) {
789 /* load the l2 table in memory */
790 l2_offset
&= ~QCOW_OFLAG_COPIED
;
791 l2_table
= l2_load(bs
, l2_offset
);
792 if (l2_table
== NULL
)
796 free_clusters(bs
, l2_offset
, s
->l2_size
* sizeof(uint64_t));
797 l2_table
= l2_allocate(bs
, l1_index
);
798 if (l2_table
== NULL
)
800 l2_offset
= s
->l1_table
[l1_index
] & ~QCOW_OFLAG_COPIED
;
803 /* find the cluster offset for the given disk offset */
805 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
807 *new_l2_table
= l2_table
;
808 *new_l2_offset
= l2_offset
;
809 *new_l2_index
= l2_index
;
815 * alloc_compressed_cluster_offset
817 * For a given offset of the disk image, return cluster offset in
820 * If the offset is not found, allocate a new compressed cluster.
822 * Return the cluster offset if successful,
823 * Return 0, otherwise.
827 static uint64_t alloc_compressed_cluster_offset(BlockDriverState
*bs
,
831 BDRVQcowState
*s
= bs
->opaque
;
833 uint64_t l2_offset
, *l2_table
, cluster_offset
;
836 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
840 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
841 if (cluster_offset
& QCOW_OFLAG_COPIED
)
842 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
845 free_any_clusters(bs
, cluster_offset
, 1);
847 cluster_offset
= alloc_bytes(bs
, compressed_size
);
848 nb_csectors
= ((cluster_offset
+ compressed_size
- 1) >> 9) -
849 (cluster_offset
>> 9);
851 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
852 ((uint64_t)nb_csectors
<< s
->csize_shift
);
854 /* update L2 table */
856 /* compressed clusters never have the copied flag */
858 l2_table
[l2_index
] = cpu_to_be64(cluster_offset
);
859 if (bdrv_pwrite(s
->hd
,
860 l2_offset
+ l2_index
* sizeof(uint64_t),
862 sizeof(uint64_t)) != sizeof(uint64_t))
865 return cluster_offset
;
868 typedef struct QCowL2Meta
876 static int alloc_cluster_link_l2(BlockDriverState
*bs
, uint64_t cluster_offset
,
879 BDRVQcowState
*s
= bs
->opaque
;
880 int i
, j
= 0, l2_index
, ret
;
881 uint64_t *old_cluster
, start_sect
, l2_offset
, *l2_table
;
883 if (m
->nb_clusters
== 0)
886 old_cluster
= qemu_malloc(m
->nb_clusters
* sizeof(uint64_t));
888 /* copy content of unmodified sectors */
889 start_sect
= (m
->offset
& ~(s
->cluster_size
- 1)) >> 9;
891 ret
= copy_sectors(bs
, start_sect
, cluster_offset
, 0, m
->n_start
);
896 if (m
->nb_available
& (s
->cluster_sectors
- 1)) {
897 uint64_t end
= m
->nb_available
& ~(uint64_t)(s
->cluster_sectors
- 1);
898 ret
= copy_sectors(bs
, start_sect
+ end
, cluster_offset
+ (end
<< 9),
899 m
->nb_available
- end
, s
->cluster_sectors
);
905 /* update L2 table */
906 if (!get_cluster_table(bs
, m
->offset
, &l2_table
, &l2_offset
, &l2_index
))
909 for (i
= 0; i
< m
->nb_clusters
; i
++) {
910 if(l2_table
[l2_index
+ i
] != 0)
911 old_cluster
[j
++] = l2_table
[l2_index
+ i
];
913 l2_table
[l2_index
+ i
] = cpu_to_be64((cluster_offset
+
914 (i
<< s
->cluster_bits
)) | QCOW_OFLAG_COPIED
);
917 if (bdrv_pwrite(s
->hd
, l2_offset
+ l2_index
* sizeof(uint64_t),
918 l2_table
+ l2_index
, m
->nb_clusters
* sizeof(uint64_t)) !=
919 m
->nb_clusters
* sizeof(uint64_t))
922 for (i
= 0; i
< j
; i
++)
923 free_any_clusters(bs
, old_cluster
[i
], 1);
927 qemu_free(old_cluster
);
932 * alloc_cluster_offset
934 * For a given offset of the disk image, return cluster offset in
937 * If the offset is not found, allocate a new cluster.
939 * Return the cluster offset if successful,
940 * Return 0, otherwise.
944 static uint64_t alloc_cluster_offset(BlockDriverState
*bs
,
946 int n_start
, int n_end
,
947 int *num
, QCowL2Meta
*m
)
949 BDRVQcowState
*s
= bs
->opaque
;
951 uint64_t l2_offset
, *l2_table
, cluster_offset
;
952 int nb_clusters
, i
= 0;
954 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
958 nb_clusters
= size_to_clusters(s
, n_end
<< 9);
960 nb_clusters
= MIN(nb_clusters
, s
->l2_size
- l2_index
);
962 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
964 /* We keep all QCOW_OFLAG_COPIED clusters */
966 if (cluster_offset
& QCOW_OFLAG_COPIED
) {
967 nb_clusters
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
968 &l2_table
[l2_index
], 0, 0);
970 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
976 /* for the moment, multiple compressed clusters are not managed */
978 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
)
981 /* how many available clusters ? */
983 while (i
< nb_clusters
) {
984 i
+= count_contiguous_clusters(nb_clusters
- i
, s
->cluster_size
,
985 &l2_table
[l2_index
], i
, 0);
987 if(be64_to_cpu(l2_table
[l2_index
+ i
]))
990 i
+= count_contiguous_free_clusters(nb_clusters
- i
,
991 &l2_table
[l2_index
+ i
]);
993 cluster_offset
= be64_to_cpu(l2_table
[l2_index
+ i
]);
995 if ((cluster_offset
& QCOW_OFLAG_COPIED
) ||
996 (cluster_offset
& QCOW_OFLAG_COMPRESSED
))
1001 /* allocate a new cluster */
1003 cluster_offset
= alloc_clusters(bs
, nb_clusters
* s
->cluster_size
);
1005 /* save info needed for meta data update */
1007 m
->n_start
= n_start
;
1008 m
->nb_clusters
= nb_clusters
;
1011 m
->nb_available
= MIN(nb_clusters
<< (s
->cluster_bits
- 9), n_end
);
1013 *num
= m
->nb_available
- n_start
;
1015 return cluster_offset
;
1018 static int qcow_is_allocated(BlockDriverState
*bs
, int64_t sector_num
,
1019 int nb_sectors
, int *pnum
)
1021 uint64_t cluster_offset
;
1024 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, pnum
);
1026 return (cluster_offset
!= 0);
1029 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
1030 const uint8_t *buf
, int buf_size
)
1032 z_stream strm1
, *strm
= &strm1
;
1035 memset(strm
, 0, sizeof(*strm
));
1037 strm
->next_in
= (uint8_t *)buf
;
1038 strm
->avail_in
= buf_size
;
1039 strm
->next_out
= out_buf
;
1040 strm
->avail_out
= out_buf_size
;
1042 ret
= inflateInit2(strm
, -12);
1045 ret
= inflate(strm
, Z_FINISH
);
1046 out_len
= strm
->next_out
- out_buf
;
1047 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
1048 out_len
!= out_buf_size
) {
1056 static int decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
)
1058 int ret
, csize
, nb_csectors
, sector_offset
;
1061 coffset
= cluster_offset
& s
->cluster_offset_mask
;
1062 if (s
->cluster_cache_offset
!= coffset
) {
1063 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
1064 sector_offset
= coffset
& 511;
1065 csize
= nb_csectors
* 512 - sector_offset
;
1066 ret
= bdrv_read(s
->hd
, coffset
>> 9, s
->cluster_data
, nb_csectors
);
1070 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
1071 s
->cluster_data
+ sector_offset
, csize
) < 0) {
1074 s
->cluster_cache_offset
= coffset
;
1079 /* handle reading after the end of the backing file */
1080 static int backing_read1(BlockDriverState
*bs
,
1081 int64_t sector_num
, uint8_t *buf
, int nb_sectors
)
1084 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
1086 if (sector_num
>= bs
->total_sectors
)
1089 n1
= bs
->total_sectors
- sector_num
;
1090 memset(buf
+ n1
* 512, 0, 512 * (nb_sectors
- n1
));
1094 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
1095 uint8_t *buf
, int nb_sectors
)
1097 BDRVQcowState
*s
= bs
->opaque
;
1098 int ret
, index_in_cluster
, n
, n1
;
1099 uint64_t cluster_offset
;
1101 while (nb_sectors
> 0) {
1103 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, &n
);
1104 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1105 if (!cluster_offset
) {
1106 if (bs
->backing_hd
) {
1107 /* read from the base image */
1108 n1
= backing_read1(bs
->backing_hd
, sector_num
, buf
, n
);
1110 ret
= bdrv_read(bs
->backing_hd
, sector_num
, buf
, n1
);
1115 memset(buf
, 0, 512 * n
);
1117 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1118 if (decompress_cluster(s
, cluster_offset
) < 0)
1120 memcpy(buf
, s
->cluster_cache
+ index_in_cluster
* 512, 512 * n
);
1122 ret
= bdrv_pread(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1125 if (s
->crypt_method
) {
1126 encrypt_sectors(s
, sector_num
, buf
, buf
, n
, 0,
1127 &s
->aes_decrypt_key
);
1137 static int qcow_write(BlockDriverState
*bs
, int64_t sector_num
,
1138 const uint8_t *buf
, int nb_sectors
)
1140 BDRVQcowState
*s
= bs
->opaque
;
1141 int ret
, index_in_cluster
, n
;
1142 uint64_t cluster_offset
;
1146 while (nb_sectors
> 0) {
1147 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1148 n_end
= index_in_cluster
+ nb_sectors
;
1149 if (s
->crypt_method
&&
1150 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1151 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1152 cluster_offset
= alloc_cluster_offset(bs
, sector_num
<< 9,
1154 n_end
, &n
, &l2meta
);
1155 if (!cluster_offset
)
1157 if (s
->crypt_method
) {
1158 encrypt_sectors(s
, sector_num
, s
->cluster_data
, buf
, n
, 1,
1159 &s
->aes_encrypt_key
);
1160 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512,
1161 s
->cluster_data
, n
* 512);
1163 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1165 if (ret
!= n
* 512 || alloc_cluster_link_l2(bs
, cluster_offset
, &l2meta
) < 0) {
1166 free_any_clusters(bs
, cluster_offset
, l2meta
.nb_clusters
);
1173 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1177 typedef struct QCowAIOCB
{
1178 BlockDriverAIOCB common
;
1183 uint64_t cluster_offset
;
1184 uint8_t *cluster_data
;
1185 BlockDriverAIOCB
*hd_aiocb
;
1190 static void qcow_aio_read_cb(void *opaque
, int ret
);
1191 static void qcow_aio_read_bh(void *opaque
)
1193 QCowAIOCB
*acb
= opaque
;
1194 qemu_bh_delete(acb
->bh
);
1196 qcow_aio_read_cb(opaque
, 0);
1199 static int qcow_schedule_bh(QEMUBHFunc
*cb
, QCowAIOCB
*acb
)
1204 acb
->bh
= qemu_bh_new(cb
, acb
);
1208 qemu_bh_schedule(acb
->bh
);
1213 static void qcow_aio_read_cb(void *opaque
, int ret
)
1215 QCowAIOCB
*acb
= opaque
;
1216 BlockDriverState
*bs
= acb
->common
.bs
;
1217 BDRVQcowState
*s
= bs
->opaque
;
1218 int index_in_cluster
, n1
;
1220 acb
->hd_aiocb
= NULL
;
1223 acb
->common
.cb(acb
->common
.opaque
, ret
);
1224 qemu_aio_release(acb
);
1228 /* post process the read buffer */
1229 if (!acb
->cluster_offset
) {
1231 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1234 if (s
->crypt_method
) {
1235 encrypt_sectors(s
, acb
->sector_num
, acb
->buf
, acb
->buf
,
1237 &s
->aes_decrypt_key
);
1241 acb
->nb_sectors
-= acb
->n
;
1242 acb
->sector_num
+= acb
->n
;
1243 acb
->buf
+= acb
->n
* 512;
1245 if (acb
->nb_sectors
== 0) {
1246 /* request completed */
1247 acb
->common
.cb(acb
->common
.opaque
, 0);
1248 qemu_aio_release(acb
);
1252 /* prepare next AIO request */
1253 acb
->n
= acb
->nb_sectors
;
1254 acb
->cluster_offset
= get_cluster_offset(bs
, acb
->sector_num
<< 9, &acb
->n
);
1255 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1257 if (!acb
->cluster_offset
) {
1258 if (bs
->backing_hd
) {
1259 /* read from the base image */
1260 n1
= backing_read1(bs
->backing_hd
, acb
->sector_num
,
1263 acb
->hd_aiocb
= bdrv_aio_read(bs
->backing_hd
, acb
->sector_num
,
1264 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1265 if (acb
->hd_aiocb
== NULL
)
1268 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1273 /* Note: in this case, no need to wait */
1274 memset(acb
->buf
, 0, 512 * acb
->n
);
1275 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1279 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1280 /* add AIO support for compressed blocks ? */
1281 if (decompress_cluster(s
, acb
->cluster_offset
) < 0)
1284 s
->cluster_cache
+ index_in_cluster
* 512, 512 * acb
->n
);
1285 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1289 if ((acb
->cluster_offset
& 511) != 0) {
1293 acb
->hd_aiocb
= bdrv_aio_read(s
->hd
,
1294 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1295 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1296 if (acb
->hd_aiocb
== NULL
)
1301 static QCowAIOCB
*qcow_aio_setup(BlockDriverState
*bs
,
1302 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1303 BlockDriverCompletionFunc
*cb
, void *opaque
)
1307 acb
= qemu_aio_get(bs
, cb
, opaque
);
1310 acb
->hd_aiocb
= NULL
;
1311 acb
->sector_num
= sector_num
;
1313 acb
->nb_sectors
= nb_sectors
;
1315 acb
->cluster_offset
= 0;
1316 acb
->l2meta
.nb_clusters
= 0;
1320 static BlockDriverAIOCB
*qcow_aio_read(BlockDriverState
*bs
,
1321 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1322 BlockDriverCompletionFunc
*cb
, void *opaque
)
1326 acb
= qcow_aio_setup(bs
, sector_num
, buf
, nb_sectors
, cb
, opaque
);
1330 qcow_aio_read_cb(acb
, 0);
1331 return &acb
->common
;
1334 static void qcow_aio_write_cb(void *opaque
, int ret
)
1336 QCowAIOCB
*acb
= opaque
;
1337 BlockDriverState
*bs
= acb
->common
.bs
;
1338 BDRVQcowState
*s
= bs
->opaque
;
1339 int index_in_cluster
;
1340 const uint8_t *src_buf
;
1343 acb
->hd_aiocb
= NULL
;
1347 acb
->common
.cb(acb
->common
.opaque
, ret
);
1348 qemu_aio_release(acb
);
1352 if (alloc_cluster_link_l2(bs
, acb
->cluster_offset
, &acb
->l2meta
) < 0) {
1353 free_any_clusters(bs
, acb
->cluster_offset
, acb
->l2meta
.nb_clusters
);
1357 acb
->nb_sectors
-= acb
->n
;
1358 acb
->sector_num
+= acb
->n
;
1359 acb
->buf
+= acb
->n
* 512;
1361 if (acb
->nb_sectors
== 0) {
1362 /* request completed */
1363 acb
->common
.cb(acb
->common
.opaque
, 0);
1364 qemu_aio_release(acb
);
1368 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1369 n_end
= index_in_cluster
+ acb
->nb_sectors
;
1370 if (s
->crypt_method
&&
1371 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1372 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1374 acb
->cluster_offset
= alloc_cluster_offset(bs
, acb
->sector_num
<< 9,
1376 n_end
, &acb
->n
, &acb
->l2meta
);
1377 if (!acb
->cluster_offset
|| (acb
->cluster_offset
& 511) != 0) {
1381 if (s
->crypt_method
) {
1382 if (!acb
->cluster_data
) {
1383 acb
->cluster_data
= qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS
*
1386 encrypt_sectors(s
, acb
->sector_num
, acb
->cluster_data
, acb
->buf
,
1387 acb
->n
, 1, &s
->aes_encrypt_key
);
1388 src_buf
= acb
->cluster_data
;
1392 acb
->hd_aiocb
= bdrv_aio_write(s
->hd
,
1393 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1395 qcow_aio_write_cb
, acb
);
1396 if (acb
->hd_aiocb
== NULL
)
1400 static BlockDriverAIOCB
*qcow_aio_write(BlockDriverState
*bs
,
1401 int64_t sector_num
, const uint8_t *buf
, int nb_sectors
,
1402 BlockDriverCompletionFunc
*cb
, void *opaque
)
1404 BDRVQcowState
*s
= bs
->opaque
;
1407 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1409 acb
= qcow_aio_setup(bs
, sector_num
, (uint8_t*)buf
, nb_sectors
, cb
, opaque
);
1413 qcow_aio_write_cb(acb
, 0);
1414 return &acb
->common
;
1417 static void qcow_aio_cancel(BlockDriverAIOCB
*blockacb
)
1419 QCowAIOCB
*acb
= (QCowAIOCB
*)blockacb
;
1421 bdrv_aio_cancel(acb
->hd_aiocb
);
1422 qemu_aio_release(acb
);
1425 static void qcow_close(BlockDriverState
*bs
)
1427 BDRVQcowState
*s
= bs
->opaque
;
1428 qemu_free(s
->l1_table
);
1429 qemu_free(s
->l2_cache
);
1430 qemu_free(s
->cluster_cache
);
1431 qemu_free(s
->cluster_data
);
1436 /* XXX: use std qcow open function ? */
1437 typedef struct QCowCreateState
{
1440 uint16_t *refcount_block
;
1441 uint64_t *refcount_table
;
1442 int64_t l1_table_offset
;
1443 int64_t refcount_table_offset
;
1444 int64_t refcount_block_offset
;
1447 static void create_refcount_update(QCowCreateState
*s
,
1448 int64_t offset
, int64_t size
)
1451 int64_t start
, last
, cluster_offset
;
1454 start
= offset
& ~(s
->cluster_size
- 1);
1455 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
1456 for(cluster_offset
= start
; cluster_offset
<= last
;
1457 cluster_offset
+= s
->cluster_size
) {
1458 p
= &s
->refcount_block
[cluster_offset
>> s
->cluster_bits
];
1459 refcount
= be16_to_cpu(*p
);
1461 *p
= cpu_to_be16(refcount
);
1465 static int qcow_create(const char *filename
, int64_t total_size
,
1466 const char *backing_file
, int flags
)
1468 int fd
, header_size
, backing_filename_len
, l1_size
, i
, shift
, l2_bits
;
1470 uint64_t tmp
, offset
;
1471 QCowCreateState s1
, *s
= &s1
;
1473 memset(s
, 0, sizeof(*s
));
1475 fd
= open(filename
, O_WRONLY
| O_CREAT
| O_TRUNC
| O_BINARY
, 0644);
1478 memset(&header
, 0, sizeof(header
));
1479 header
.magic
= cpu_to_be32(QCOW_MAGIC
);
1480 header
.version
= cpu_to_be32(QCOW_VERSION
);
1481 header
.size
= cpu_to_be64(total_size
* 512);
1482 header_size
= sizeof(header
);
1483 backing_filename_len
= 0;
1485 header
.backing_file_offset
= cpu_to_be64(header_size
);
1486 backing_filename_len
= strlen(backing_file
);
1487 header
.backing_file_size
= cpu_to_be32(backing_filename_len
);
1488 header_size
+= backing_filename_len
;
1490 s
->cluster_bits
= 12; /* 4 KB clusters */
1491 s
->cluster_size
= 1 << s
->cluster_bits
;
1492 header
.cluster_bits
= cpu_to_be32(s
->cluster_bits
);
1493 header_size
= (header_size
+ 7) & ~7;
1494 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1495 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1497 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1499 l2_bits
= s
->cluster_bits
- 3;
1500 shift
= s
->cluster_bits
+ l2_bits
;
1501 l1_size
= (((total_size
* 512) + (1LL << shift
) - 1) >> shift
);
1502 offset
= align_offset(header_size
, s
->cluster_size
);
1503 s
->l1_table_offset
= offset
;
1504 header
.l1_table_offset
= cpu_to_be64(s
->l1_table_offset
);
1505 header
.l1_size
= cpu_to_be32(l1_size
);
1506 offset
+= align_offset(l1_size
* sizeof(uint64_t), s
->cluster_size
);
1508 s
->refcount_table
= qemu_mallocz(s
->cluster_size
);
1509 s
->refcount_block
= qemu_mallocz(s
->cluster_size
);
1511 s
->refcount_table_offset
= offset
;
1512 header
.refcount_table_offset
= cpu_to_be64(offset
);
1513 header
.refcount_table_clusters
= cpu_to_be32(1);
1514 offset
+= s
->cluster_size
;
1516 s
->refcount_table
[0] = cpu_to_be64(offset
);
1517 s
->refcount_block_offset
= offset
;
1518 offset
+= s
->cluster_size
;
1520 /* update refcounts */
1521 create_refcount_update(s
, 0, header_size
);
1522 create_refcount_update(s
, s
->l1_table_offset
, l1_size
* sizeof(uint64_t));
1523 create_refcount_update(s
, s
->refcount_table_offset
, s
->cluster_size
);
1524 create_refcount_update(s
, s
->refcount_block_offset
, s
->cluster_size
);
1526 /* write all the data */
1527 write(fd
, &header
, sizeof(header
));
1529 write(fd
, backing_file
, backing_filename_len
);
1531 lseek(fd
, s
->l1_table_offset
, SEEK_SET
);
1533 for(i
= 0;i
< l1_size
; i
++) {
1534 write(fd
, &tmp
, sizeof(tmp
));
1536 lseek(fd
, s
->refcount_table_offset
, SEEK_SET
);
1537 write(fd
, s
->refcount_table
, s
->cluster_size
);
1539 lseek(fd
, s
->refcount_block_offset
, SEEK_SET
);
1540 write(fd
, s
->refcount_block
, s
->cluster_size
);
1542 qemu_free(s
->refcount_table
);
1543 qemu_free(s
->refcount_block
);
1548 static int qcow_make_empty(BlockDriverState
*bs
)
1551 /* XXX: not correct */
1552 BDRVQcowState
*s
= bs
->opaque
;
1553 uint32_t l1_length
= s
->l1_size
* sizeof(uint64_t);
1556 memset(s
->l1_table
, 0, l1_length
);
1557 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
, s
->l1_table
, l1_length
) < 0)
1559 ret
= bdrv_truncate(s
->hd
, s
->l1_table_offset
+ l1_length
);
1568 /* XXX: put compressed sectors first, then all the cluster aligned
1569 tables to avoid losing bytes in alignment */
1570 static int qcow_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1571 const uint8_t *buf
, int nb_sectors
)
1573 BDRVQcowState
*s
= bs
->opaque
;
1577 uint64_t cluster_offset
;
1579 if (nb_sectors
== 0) {
1580 /* align end of file to a sector boundary to ease reading with
1581 sector based I/Os */
1582 cluster_offset
= bdrv_getlength(s
->hd
);
1583 cluster_offset
= (cluster_offset
+ 511) & ~511;
1584 bdrv_truncate(s
->hd
, cluster_offset
);
1588 if (nb_sectors
!= s
->cluster_sectors
)
1591 out_buf
= qemu_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
1593 /* best compression, small window, no zlib header */
1594 memset(&strm
, 0, sizeof(strm
));
1595 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1597 9, Z_DEFAULT_STRATEGY
);
1603 strm
.avail_in
= s
->cluster_size
;
1604 strm
.next_in
= (uint8_t *)buf
;
1605 strm
.avail_out
= s
->cluster_size
;
1606 strm
.next_out
= out_buf
;
1608 ret
= deflate(&strm
, Z_FINISH
);
1609 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1614 out_len
= strm
.next_out
- out_buf
;
1618 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1619 /* could not compress: write normal cluster */
1620 qcow_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
1622 cluster_offset
= alloc_compressed_cluster_offset(bs
, sector_num
<< 9,
1624 if (!cluster_offset
)
1626 cluster_offset
&= s
->cluster_offset_mask
;
1627 if (bdrv_pwrite(s
->hd
, cluster_offset
, out_buf
, out_len
) != out_len
) {
1637 static void qcow_flush(BlockDriverState
*bs
)
1639 BDRVQcowState
*s
= bs
->opaque
;
1643 static int qcow_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
1645 BDRVQcowState
*s
= bs
->opaque
;
1646 bdi
->cluster_size
= s
->cluster_size
;
1647 bdi
->vm_state_offset
= (int64_t)s
->l1_vm_state_index
<<
1648 (s
->cluster_bits
+ s
->l2_bits
);
1649 bdi
->highest_alloc
= s
->highest_alloc
<< s
->cluster_bits
;
1650 bdi
->num_free_bytes
= s
->nc_free
<< s
->cluster_bits
;
1654 /*********************************************************/
1655 /* snapshot support */
1657 /* update the refcounts of snapshots and the copied flag */
1658 static int update_snapshot_refcount(BlockDriverState
*bs
,
1659 int64_t l1_table_offset
,
1663 BDRVQcowState
*s
= bs
->opaque
;
1664 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
, l1_allocated
;
1665 int64_t old_offset
, old_l2_offset
;
1666 int l2_size
, i
, j
, l1_modified
, l2_modified
, nb_csectors
, refcount
;
1672 l1_size2
= l1_size
* sizeof(uint64_t);
1674 if (l1_table_offset
!= s
->l1_table_offset
) {
1675 l1_table
= qemu_malloc(l1_size2
);
1677 if (bdrv_pread(s
->hd
, l1_table_offset
,
1678 l1_table
, l1_size2
) != l1_size2
)
1680 for(i
= 0;i
< l1_size
; i
++)
1681 be64_to_cpus(&l1_table
[i
]);
1683 assert(l1_size
== s
->l1_size
);
1684 l1_table
= s
->l1_table
;
1688 l2_size
= s
->l2_size
* sizeof(uint64_t);
1689 l2_table
= qemu_malloc(l2_size
);
1691 for(i
= 0; i
< l1_size
; i
++) {
1692 l2_offset
= l1_table
[i
];
1694 old_l2_offset
= l2_offset
;
1695 l2_offset
&= ~QCOW_OFLAG_COPIED
;
1697 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
1699 for(j
= 0; j
< s
->l2_size
; j
++) {
1700 offset
= be64_to_cpu(l2_table
[j
]);
1702 old_offset
= offset
;
1703 offset
&= ~QCOW_OFLAG_COPIED
;
1704 if (offset
& QCOW_OFLAG_COMPRESSED
) {
1705 nb_csectors
= ((offset
>> s
->csize_shift
) &
1708 update_refcount(bs
, (offset
& s
->cluster_offset_mask
) & ~511,
1709 nb_csectors
* 512, addend
);
1710 /* compressed clusters are never modified */
1714 refcount
= update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, addend
);
1716 refcount
= get_refcount(bs
, offset
>> s
->cluster_bits
);
1720 if (refcount
== 1) {
1721 offset
|= QCOW_OFLAG_COPIED
;
1723 if (offset
!= old_offset
) {
1724 l2_table
[j
] = cpu_to_be64(offset
);
1730 if (bdrv_pwrite(s
->hd
,
1731 l2_offset
, l2_table
, l2_size
) != l2_size
)
1736 refcount
= update_cluster_refcount(bs
, l2_offset
>> s
->cluster_bits
, addend
);
1738 refcount
= get_refcount(bs
, l2_offset
>> s
->cluster_bits
);
1740 if (refcount
== 1) {
1741 l2_offset
|= QCOW_OFLAG_COPIED
;
1743 if (l2_offset
!= old_l2_offset
) {
1744 l1_table
[i
] = l2_offset
;
1750 for(i
= 0; i
< l1_size
; i
++)
1751 cpu_to_be64s(&l1_table
[i
]);
1752 if (bdrv_pwrite(s
->hd
, l1_table_offset
, l1_table
,
1753 l1_size2
) != l1_size2
)
1755 for(i
= 0; i
< l1_size
; i
++)
1756 be64_to_cpus(&l1_table
[i
]);
1759 qemu_free(l1_table
);
1760 qemu_free(l2_table
);
1764 qemu_free(l1_table
);
1765 qemu_free(l2_table
);
1769 static void qcow_free_snapshots(BlockDriverState
*bs
)
1771 BDRVQcowState
*s
= bs
->opaque
;
1774 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1775 qemu_free(s
->snapshots
[i
].name
);
1776 qemu_free(s
->snapshots
[i
].id_str
);
1778 qemu_free(s
->snapshots
);
1779 s
->snapshots
= NULL
;
1780 s
->nb_snapshots
= 0;
1783 static int qcow_read_snapshots(BlockDriverState
*bs
)
1785 BDRVQcowState
*s
= bs
->opaque
;
1786 QCowSnapshotHeader h
;
1788 int i
, id_str_size
, name_size
;
1790 uint32_t extra_data_size
;
1792 if (!s
->nb_snapshots
) {
1793 s
->snapshots
= NULL
;
1794 s
->snapshots_size
= 0;
1798 offset
= s
->snapshots_offset
;
1799 s
->snapshots
= qemu_mallocz(s
->nb_snapshots
* sizeof(QCowSnapshot
));
1800 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1801 offset
= align_offset(offset
, 8);
1802 if (bdrv_pread(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1804 offset
+= sizeof(h
);
1805 sn
= s
->snapshots
+ i
;
1806 sn
->l1_table_offset
= be64_to_cpu(h
.l1_table_offset
);
1807 sn
->l1_size
= be32_to_cpu(h
.l1_size
);
1808 sn
->vm_state_size
= be32_to_cpu(h
.vm_state_size
);
1809 sn
->date_sec
= be32_to_cpu(h
.date_sec
);
1810 sn
->date_nsec
= be32_to_cpu(h
.date_nsec
);
1811 sn
->vm_clock_nsec
= be64_to_cpu(h
.vm_clock_nsec
);
1812 extra_data_size
= be32_to_cpu(h
.extra_data_size
);
1814 id_str_size
= be16_to_cpu(h
.id_str_size
);
1815 name_size
= be16_to_cpu(h
.name_size
);
1817 offset
+= extra_data_size
;
1819 sn
->id_str
= qemu_malloc(id_str_size
+ 1);
1820 if (bdrv_pread(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1822 offset
+= id_str_size
;
1823 sn
->id_str
[id_str_size
] = '\0';
1825 sn
->name
= qemu_malloc(name_size
+ 1);
1826 if (bdrv_pread(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1828 offset
+= name_size
;
1829 sn
->name
[name_size
] = '\0';
1831 s
->snapshots_size
= offset
- s
->snapshots_offset
;
1834 qcow_free_snapshots(bs
);
1838 /* add at the end of the file a new list of snapshots */
1839 static int qcow_write_snapshots(BlockDriverState
*bs
)
1841 BDRVQcowState
*s
= bs
->opaque
;
1843 QCowSnapshotHeader h
;
1844 int i
, name_size
, id_str_size
, snapshots_size
;
1847 int64_t offset
, snapshots_offset
;
1849 /* compute the size of the snapshots */
1851 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1852 sn
= s
->snapshots
+ i
;
1853 offset
= align_offset(offset
, 8);
1854 offset
+= sizeof(h
);
1855 offset
+= strlen(sn
->id_str
);
1856 offset
+= strlen(sn
->name
);
1858 snapshots_size
= offset
;
1860 snapshots_offset
= alloc_clusters(bs
, snapshots_size
);
1861 offset
= snapshots_offset
;
1863 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1864 sn
= s
->snapshots
+ i
;
1865 memset(&h
, 0, sizeof(h
));
1866 h
.l1_table_offset
= cpu_to_be64(sn
->l1_table_offset
);
1867 h
.l1_size
= cpu_to_be32(sn
->l1_size
);
1868 h
.vm_state_size
= cpu_to_be32(sn
->vm_state_size
);
1869 h
.date_sec
= cpu_to_be32(sn
->date_sec
);
1870 h
.date_nsec
= cpu_to_be32(sn
->date_nsec
);
1871 h
.vm_clock_nsec
= cpu_to_be64(sn
->vm_clock_nsec
);
1873 id_str_size
= strlen(sn
->id_str
);
1874 name_size
= strlen(sn
->name
);
1875 h
.id_str_size
= cpu_to_be16(id_str_size
);
1876 h
.name_size
= cpu_to_be16(name_size
);
1877 offset
= align_offset(offset
, 8);
1878 if (bdrv_pwrite(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1880 offset
+= sizeof(h
);
1881 if (bdrv_pwrite(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1883 offset
+= id_str_size
;
1884 if (bdrv_pwrite(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1886 offset
+= name_size
;
1889 /* update the various header fields */
1890 data64
= cpu_to_be64(snapshots_offset
);
1891 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, snapshots_offset
),
1892 &data64
, sizeof(data64
)) != sizeof(data64
))
1894 data32
= cpu_to_be32(s
->nb_snapshots
);
1895 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, nb_snapshots
),
1896 &data32
, sizeof(data32
)) != sizeof(data32
))
1899 /* free the old snapshot table */
1900 free_clusters(bs
, s
->snapshots_offset
, s
->snapshots_size
);
1901 s
->snapshots_offset
= snapshots_offset
;
1902 s
->snapshots_size
= snapshots_size
;
1908 static void find_new_snapshot_id(BlockDriverState
*bs
,
1909 char *id_str
, int id_str_size
)
1911 BDRVQcowState
*s
= bs
->opaque
;
1913 int i
, id
, id_max
= 0;
1915 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1916 sn
= s
->snapshots
+ i
;
1917 id
= strtoul(sn
->id_str
, NULL
, 10);
1921 snprintf(id_str
, id_str_size
, "%d", id_max
+ 1);
1924 static int find_snapshot_by_id(BlockDriverState
*bs
, const char *id_str
)
1926 BDRVQcowState
*s
= bs
->opaque
;
1929 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1930 if (!strcmp(s
->snapshots
[i
].id_str
, id_str
))
1936 static int find_snapshot_by_id_or_name(BlockDriverState
*bs
, const char *name
)
1938 BDRVQcowState
*s
= bs
->opaque
;
1941 ret
= find_snapshot_by_id(bs
, name
);
1944 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1945 if (!strcmp(s
->snapshots
[i
].name
, name
))
1951 /* if no id is provided, a new one is constructed */
1952 static int qcow_snapshot_create(BlockDriverState
*bs
,
1953 QEMUSnapshotInfo
*sn_info
)
1955 BDRVQcowState
*s
= bs
->opaque
;
1956 QCowSnapshot
*snapshots1
, sn1
, *sn
= &sn1
;
1958 uint64_t *l1_table
= NULL
;
1960 memset(sn
, 0, sizeof(*sn
));
1962 if (sn_info
->id_str
[0] == '\0') {
1963 /* compute a new id */
1964 find_new_snapshot_id(bs
, sn_info
->id_str
, sizeof(sn_info
->id_str
));
1967 /* check that the ID is unique */
1968 if (find_snapshot_by_id(bs
, sn_info
->id_str
) >= 0)
1971 sn
->id_str
= qemu_strdup(sn_info
->id_str
);
1974 sn
->name
= qemu_strdup(sn_info
->name
);
1977 sn
->vm_state_size
= sn_info
->vm_state_size
;
1978 sn
->date_sec
= sn_info
->date_sec
;
1979 sn
->date_nsec
= sn_info
->date_nsec
;
1980 sn
->vm_clock_nsec
= sn_info
->vm_clock_nsec
;
1982 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1);
1986 /* create the L1 table of the snapshot */
1987 sn
->l1_table_offset
= alloc_clusters(bs
, s
->l1_size
* sizeof(uint64_t));
1988 sn
->l1_size
= s
->l1_size
;
1990 l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
1991 for(i
= 0; i
< s
->l1_size
; i
++) {
1992 l1_table
[i
] = cpu_to_be64(s
->l1_table
[i
]);
1994 if (bdrv_pwrite(s
->hd
, sn
->l1_table_offset
,
1995 l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
1996 (s
->l1_size
* sizeof(uint64_t)))
1998 qemu_free(l1_table
);
2001 snapshots1
= qemu_malloc((s
->nb_snapshots
+ 1) * sizeof(QCowSnapshot
));
2003 memcpy(snapshots1
, s
->snapshots
, s
->nb_snapshots
* sizeof(QCowSnapshot
));
2004 qemu_free(s
->snapshots
);
2006 s
->snapshots
= snapshots1
;
2007 s
->snapshots
[s
->nb_snapshots
++] = *sn
;
2009 if (qcow_write_snapshots(bs
) < 0)
2012 check_refcounts(bs
);
2016 qemu_free(sn
->name
);
2017 qemu_free(l1_table
);
2021 /* copy the snapshot 'snapshot_name' into the current disk image */
2022 static int qcow_snapshot_goto(BlockDriverState
*bs
,
2023 const char *snapshot_id
)
2025 BDRVQcowState
*s
= bs
->opaque
;
2027 int i
, snapshot_index
, l1_size2
;
2029 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2030 if (snapshot_index
< 0)
2032 sn
= &s
->snapshots
[snapshot_index
];
2034 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, -1) < 0)
2037 if (grow_l1_table(bs
, sn
->l1_size
) < 0)
2040 s
->l1_size
= sn
->l1_size
;
2041 l1_size2
= s
->l1_size
* sizeof(uint64_t);
2042 /* copy the snapshot l1 table to the current l1 table */
2043 if (bdrv_pread(s
->hd
, sn
->l1_table_offset
,
2044 s
->l1_table
, l1_size2
) != l1_size2
)
2046 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
,
2047 s
->l1_table
, l1_size2
) != l1_size2
)
2049 for(i
= 0;i
< s
->l1_size
; i
++) {
2050 be64_to_cpus(&s
->l1_table
[i
]);
2053 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1) < 0)
2057 check_refcounts(bs
);
2064 static int qcow_snapshot_delete(BlockDriverState
*bs
, const char *snapshot_id
)
2066 BDRVQcowState
*s
= bs
->opaque
;
2068 int snapshot_index
, ret
;
2070 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2071 if (snapshot_index
< 0)
2073 sn
= &s
->snapshots
[snapshot_index
];
2075 ret
= update_snapshot_refcount(bs
, sn
->l1_table_offset
, sn
->l1_size
, -1);
2078 /* must update the copied flag on the current cluster offsets */
2079 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 0);
2082 free_clusters(bs
, sn
->l1_table_offset
, sn
->l1_size
* sizeof(uint64_t));
2084 qemu_free(sn
->id_str
);
2085 qemu_free(sn
->name
);
2086 memmove(sn
, sn
+ 1, (s
->nb_snapshots
- snapshot_index
- 1) * sizeof(*sn
));
2088 ret
= qcow_write_snapshots(bs
);
2090 /* XXX: restore snapshot if error ? */
2094 check_refcounts(bs
);
2099 static int qcow_snapshot_list(BlockDriverState
*bs
,
2100 QEMUSnapshotInfo
**psn_tab
)
2102 BDRVQcowState
*s
= bs
->opaque
;
2103 QEMUSnapshotInfo
*sn_tab
, *sn_info
;
2107 sn_tab
= qemu_mallocz(s
->nb_snapshots
* sizeof(QEMUSnapshotInfo
));
2108 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2109 sn_info
= sn_tab
+ i
;
2110 sn
= s
->snapshots
+ i
;
2111 pstrcpy(sn_info
->id_str
, sizeof(sn_info
->id_str
),
2113 pstrcpy(sn_info
->name
, sizeof(sn_info
->name
),
2115 sn_info
->vm_state_size
= sn
->vm_state_size
;
2116 sn_info
->date_sec
= sn
->date_sec
;
2117 sn_info
->date_nsec
= sn
->date_nsec
;
2118 sn_info
->vm_clock_nsec
= sn
->vm_clock_nsec
;
2121 return s
->nb_snapshots
;
2124 /*********************************************************/
2125 /* refcount handling */
2127 static int refcount_init(BlockDriverState
*bs
)
2129 BDRVQcowState
*s
= bs
->opaque
;
2130 int ret
, refcount_table_size2
, i
;
2132 s
->refcount_block_cache
= qemu_malloc(s
->cluster_size
);
2133 refcount_table_size2
= s
->refcount_table_size
* sizeof(uint64_t);
2134 s
->refcount_table
= qemu_malloc(refcount_table_size2
);
2135 if (s
->refcount_table_size
> 0) {
2136 ret
= bdrv_pread(s
->hd
, s
->refcount_table_offset
,
2137 s
->refcount_table
, refcount_table_size2
);
2138 if (ret
!= refcount_table_size2
)
2140 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2141 be64_to_cpus(&s
->refcount_table
[i
]);
2148 static void refcount_close(BlockDriverState
*bs
)
2150 BDRVQcowState
*s
= bs
->opaque
;
2151 qemu_free(s
->refcount_block_cache
);
2152 qemu_free(s
->refcount_table
);
2156 static int load_refcount_block(BlockDriverState
*bs
,
2157 int64_t refcount_block_offset
)
2159 BDRVQcowState
*s
= bs
->opaque
;
2161 ret
= bdrv_pread(s
->hd
, refcount_block_offset
, s
->refcount_block_cache
,
2163 if (ret
!= s
->cluster_size
)
2165 s
->refcount_block_cache_offset
= refcount_block_offset
;
2169 static void scan_refcount(BlockDriverState
*bs
, int64_t *high
, int64_t *free
)
2171 BDRVQcowState
*s
= bs
->opaque
;
2172 int64_t refcnt_index
, cluster_index
, cluster_end
, h
= 0, f
= 0;
2173 int64_t tail
= 0; /* do not count last consecutive free entries */
2175 for (refcnt_index
=0; refcnt_index
< s
->refcount_table_size
; refcnt_index
++){
2176 if (s
->refcount_table
[refcnt_index
] == 0) {
2177 f
+= 1 << (s
->cluster_bits
- REFCOUNT_SHIFT
);
2178 tail
+= 1 << (s
->cluster_bits
- REFCOUNT_SHIFT
);
2181 cluster_index
= refcnt_index
<< (s
->cluster_bits
- REFCOUNT_SHIFT
);
2182 cluster_end
= (refcnt_index
+ 1) << (s
->cluster_bits
- REFCOUNT_SHIFT
);
2183 for ( ; cluster_index
< cluster_end
; cluster_index
++) {
2184 if (get_refcount(bs
, cluster_index
) == 0) {
2202 static int get_refcount(BlockDriverState
*bs
, int64_t cluster_index
)
2204 BDRVQcowState
*s
= bs
->opaque
;
2205 int refcount_table_index
, block_index
;
2206 int64_t refcount_block_offset
;
2208 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2209 if (refcount_table_index
>= s
->refcount_table_size
)
2211 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2212 if (!refcount_block_offset
)
2214 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2215 /* better than nothing: return allocated if read error */
2216 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2219 block_index
= cluster_index
&
2220 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2221 return be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2224 /* return < 0 if error */
2225 static int64_t alloc_clusters_noref(BlockDriverState
*bs
, int64_t size
)
2227 BDRVQcowState
*s
= bs
->opaque
;
2230 nb_clusters
= size_to_clusters(s
, size
);
2232 for(i
= 0; i
< nb_clusters
; i
++) {
2233 int64_t i
= s
->free_cluster_index
++;
2234 if (get_refcount(bs
, i
) != 0)
2238 printf("alloc_clusters: size=%lld -> %lld\n",
2240 (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
);
2243 if (s
->highest_alloc
< s
->free_cluster_index
) {
2244 s
->nc_free
+= (s
->free_cluster_index
- s
->highest_alloc
);
2245 s
->highest_alloc
= s
->free_cluster_index
;
2248 return (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
;
2251 static int64_t alloc_clusters(BlockDriverState
*bs
, int64_t size
)
2255 offset
= alloc_clusters_noref(bs
, size
);
2256 update_refcount(bs
, offset
, size
, 1);
2260 /* only used to allocate compressed sectors. We try to allocate
2261 contiguous sectors. size must be <= cluster_size */
2262 static int64_t alloc_bytes(BlockDriverState
*bs
, int size
)
2264 BDRVQcowState
*s
= bs
->opaque
;
2265 int64_t offset
, cluster_offset
;
2266 int free_in_cluster
;
2268 assert(size
> 0 && size
<= s
->cluster_size
);
2269 if (s
->free_byte_offset
== 0) {
2270 s
->free_byte_offset
= alloc_clusters(bs
, s
->cluster_size
);
2273 free_in_cluster
= s
->cluster_size
-
2274 (s
->free_byte_offset
& (s
->cluster_size
- 1));
2275 if (size
<= free_in_cluster
) {
2276 /* enough space in current cluster */
2277 offset
= s
->free_byte_offset
;
2278 s
->free_byte_offset
+= size
;
2279 free_in_cluster
-= size
;
2280 if (free_in_cluster
== 0)
2281 s
->free_byte_offset
= 0;
2282 if ((offset
& (s
->cluster_size
- 1)) != 0)
2283 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2285 offset
= alloc_clusters(bs
, s
->cluster_size
);
2286 cluster_offset
= s
->free_byte_offset
& ~(s
->cluster_size
- 1);
2287 if ((cluster_offset
+ s
->cluster_size
) == offset
) {
2288 /* we are lucky: contiguous data */
2289 offset
= s
->free_byte_offset
;
2290 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2291 s
->free_byte_offset
+= size
;
2293 s
->free_byte_offset
= offset
;
2300 static void free_clusters(BlockDriverState
*bs
,
2301 int64_t offset
, int64_t size
)
2303 update_refcount(bs
, offset
, size
, -1);
2306 static int grow_refcount_table(BlockDriverState
*bs
, int min_size
)
2308 BDRVQcowState
*s
= bs
->opaque
;
2309 int new_table_size
, new_table_size2
, refcount_table_clusters
, i
, ret
;
2310 uint64_t *new_table
;
2311 int64_t table_offset
;
2314 int64_t old_table_offset
;
2316 if (min_size
<= s
->refcount_table_size
)
2318 /* compute new table size */
2319 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
2321 if (refcount_table_clusters
== 0) {
2322 refcount_table_clusters
= 1;
2324 refcount_table_clusters
= (refcount_table_clusters
* 3 + 1) / 2;
2326 new_table_size
= refcount_table_clusters
<< (s
->cluster_bits
- 3);
2327 if (min_size
<= new_table_size
)
2331 printf("grow_refcount_table from %d to %d\n",
2332 s
->refcount_table_size
,
2335 new_table_size2
= new_table_size
* sizeof(uint64_t);
2336 new_table
= qemu_mallocz(new_table_size2
);
2337 memcpy(new_table
, s
->refcount_table
,
2338 s
->refcount_table_size
* sizeof(uint64_t));
2339 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2340 cpu_to_be64s(&new_table
[i
]);
2341 /* Note: we cannot update the refcount now to avoid recursion */
2342 table_offset
= alloc_clusters_noref(bs
, new_table_size2
);
2343 ret
= bdrv_pwrite(s
->hd
, table_offset
, new_table
, new_table_size2
);
2344 if (ret
!= new_table_size2
)
2346 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2347 be64_to_cpus(&new_table
[i
]);
2349 cpu_to_be64w((uint64_t*)data
, table_offset
);
2350 cpu_to_be32w((uint32_t*)(data
+ 8), refcount_table_clusters
);
2351 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, refcount_table_offset
),
2352 data
, sizeof(data
)) != sizeof(data
))
2354 qemu_free(s
->refcount_table
);
2355 old_table_offset
= s
->refcount_table_offset
;
2356 old_table_size
= s
->refcount_table_size
;
2357 s
->refcount_table
= new_table
;
2358 s
->refcount_table_size
= new_table_size
;
2359 s
->refcount_table_offset
= table_offset
;
2361 update_refcount(bs
, table_offset
, new_table_size2
, 1);
2362 free_clusters(bs
, old_table_offset
, old_table_size
* sizeof(uint64_t));
2365 free_clusters(bs
, table_offset
, new_table_size2
);
2366 qemu_free(new_table
);
2370 /* addend must be 1 or -1 */
2371 /* XXX: cache several refcount block clusters ? */
2372 static int update_cluster_refcount(BlockDriverState
*bs
,
2373 int64_t cluster_index
,
2376 BDRVQcowState
*s
= bs
->opaque
;
2377 int64_t offset
, refcount_block_offset
;
2378 int ret
, refcount_table_index
, block_index
, refcount
;
2381 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2382 if (refcount_table_index
>= s
->refcount_table_size
) {
2385 ret
= grow_refcount_table(bs
, refcount_table_index
+ 1);
2389 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2390 if (!refcount_block_offset
) {
2393 /* create a new refcount block */
2394 /* Note: we cannot update the refcount now to avoid recursion */
2395 offset
= alloc_clusters_noref(bs
, s
->cluster_size
);
2396 memset(s
->refcount_block_cache
, 0, s
->cluster_size
);
2397 ret
= bdrv_pwrite(s
->hd
, offset
, s
->refcount_block_cache
, s
->cluster_size
);
2398 if (ret
!= s
->cluster_size
)
2400 s
->refcount_table
[refcount_table_index
] = offset
;
2401 data64
= cpu_to_be64(offset
);
2402 ret
= bdrv_pwrite(s
->hd
, s
->refcount_table_offset
+
2403 refcount_table_index
* sizeof(uint64_t),
2404 &data64
, sizeof(data64
));
2405 if (ret
!= sizeof(data64
))
2408 refcount_block_offset
= offset
;
2409 s
->refcount_block_cache_offset
= offset
;
2410 update_refcount(bs
, offset
, s
->cluster_size
, 1);
2412 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2413 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2417 /* we can update the count and save it */
2418 block_index
= cluster_index
&
2419 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2420 refcount
= be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2422 if (refcount
== 1 && addend
== -1)
2424 else if (refcount
== 0 && addend
== 1)
2428 if (refcount
< 0 || refcount
> 0xffff)
2430 if (refcount
== 0 && cluster_index
< s
->free_cluster_index
) {
2431 s
->free_cluster_index
= cluster_index
;
2433 s
->refcount_block_cache
[block_index
] = cpu_to_be16(refcount
);
2434 if (bdrv_pwrite(s
->hd
,
2435 refcount_block_offset
+ (block_index
<< REFCOUNT_SHIFT
),
2436 &s
->refcount_block_cache
[block_index
], 2) != 2)
2441 static void update_refcount(BlockDriverState
*bs
,
2442 int64_t offset
, int64_t length
,
2445 BDRVQcowState
*s
= bs
->opaque
;
2446 int64_t start
, last
, cluster_offset
;
2449 printf("update_refcount: offset=%lld size=%lld addend=%d\n",
2450 offset
, length
, addend
);
2454 start
= offset
& ~(s
->cluster_size
- 1);
2455 last
= (offset
+ length
- 1) & ~(s
->cluster_size
- 1);
2456 for(cluster_offset
= start
; cluster_offset
<= last
;
2457 cluster_offset
+= s
->cluster_size
) {
2458 update_cluster_refcount(bs
, cluster_offset
>> s
->cluster_bits
, addend
);
2463 static void inc_refcounts(BlockDriverState
*bs
,
2464 uint16_t *refcount_table
,
2465 int refcount_table_size
,
2466 int64_t offset
, int64_t size
)
2468 BDRVQcowState
*s
= bs
->opaque
;
2469 int64_t start
, last
, cluster_offset
;
2475 start
= offset
& ~(s
->cluster_size
- 1);
2476 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
2477 for(cluster_offset
= start
; cluster_offset
<= last
;
2478 cluster_offset
+= s
->cluster_size
) {
2479 k
= cluster_offset
>> s
->cluster_bits
;
2480 if (k
< 0 || k
>= refcount_table_size
) {
2481 printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset
);
2483 if (++refcount_table
[k
] == 0) {
2484 printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset
);
2490 static int check_refcounts_l1(BlockDriverState
*bs
,
2491 uint16_t *refcount_table
,
2492 int refcount_table_size
,
2493 int64_t l1_table_offset
, int l1_size
,
2496 BDRVQcowState
*s
= bs
->opaque
;
2497 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
;
2498 int l2_size
, i
, j
, nb_csectors
, refcount
;
2501 l1_size2
= l1_size
* sizeof(uint64_t);
2503 inc_refcounts(bs
, refcount_table
, refcount_table_size
,
2504 l1_table_offset
, l1_size2
);
2506 l1_table
= qemu_malloc(l1_size2
);
2507 if (bdrv_pread(s
->hd
, l1_table_offset
,
2508 l1_table
, l1_size2
) != l1_size2
)
2510 for(i
= 0;i
< l1_size
; i
++)
2511 be64_to_cpus(&l1_table
[i
]);
2513 l2_size
= s
->l2_size
* sizeof(uint64_t);
2514 l2_table
= qemu_malloc(l2_size
);
2515 for(i
= 0; i
< l1_size
; i
++) {
2516 l2_offset
= l1_table
[i
];
2519 refcount
= get_refcount(bs
, (l2_offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2520 if ((refcount
== 1) != ((l2_offset
& QCOW_OFLAG_COPIED
) != 0)) {
2521 printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
2522 l2_offset
, refcount
);
2525 l2_offset
&= ~QCOW_OFLAG_COPIED
;
2526 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
2528 for(j
= 0; j
< s
->l2_size
; j
++) {
2529 offset
= be64_to_cpu(l2_table
[j
]);
2531 if (offset
& QCOW_OFLAG_COMPRESSED
) {
2532 if (offset
& QCOW_OFLAG_COPIED
) {
2533 printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
2534 offset
>> s
->cluster_bits
);
2535 offset
&= ~QCOW_OFLAG_COPIED
;
2537 nb_csectors
= ((offset
>> s
->csize_shift
) &
2539 offset
&= s
->cluster_offset_mask
;
2540 inc_refcounts(bs
, refcount_table
,
2541 refcount_table_size
,
2542 offset
& ~511, nb_csectors
* 512);
2545 refcount
= get_refcount(bs
, (offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2546 if ((refcount
== 1) != ((offset
& QCOW_OFLAG_COPIED
) != 0)) {
2547 printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
2551 offset
&= ~QCOW_OFLAG_COPIED
;
2552 inc_refcounts(bs
, refcount_table
,
2553 refcount_table_size
,
2554 offset
, s
->cluster_size
);
2558 inc_refcounts(bs
, refcount_table
,
2559 refcount_table_size
,
2564 qemu_free(l1_table
);
2565 qemu_free(l2_table
);
2568 printf("ERROR: I/O error in check_refcounts_l1\n");
2569 qemu_free(l1_table
);
2570 qemu_free(l2_table
);
2574 static void check_refcounts(BlockDriverState
*bs
)
2576 BDRVQcowState
*s
= bs
->opaque
;
2578 int nb_clusters
, refcount1
, refcount2
, i
;
2580 uint16_t *refcount_table
;
2582 size
= bdrv_getlength(s
->hd
);
2583 nb_clusters
= size_to_clusters(s
, size
);
2584 refcount_table
= qemu_mallocz(nb_clusters
* sizeof(uint16_t));
2587 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2588 0, s
->cluster_size
);
2590 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2591 s
->l1_table_offset
, s
->l1_size
, 1);
2594 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2595 sn
= s
->snapshots
+ i
;
2596 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2597 sn
->l1_table_offset
, sn
->l1_size
, 0);
2599 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2600 s
->snapshots_offset
, s
->snapshots_size
);
2603 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2604 s
->refcount_table_offset
,
2605 s
->refcount_table_size
* sizeof(uint64_t));
2606 for(i
= 0; i
< s
->refcount_table_size
; i
++) {
2608 offset
= s
->refcount_table
[i
];
2610 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2611 offset
, s
->cluster_size
);
2615 /* compare ref counts */
2616 for(i
= 0; i
< nb_clusters
; i
++) {
2617 refcount1
= get_refcount(bs
, i
);
2618 refcount2
= refcount_table
[i
];
2619 if (refcount1
!= refcount2
)
2620 printf("ERROR cluster %d refcount=%d reference=%d\n",
2621 i
, refcount1
, refcount2
);
2624 qemu_free(refcount_table
);
2628 static void dump_refcounts(BlockDriverState
*bs
)
2630 BDRVQcowState
*s
= bs
->opaque
;
2631 int64_t nb_clusters
, k
, k1
, size
;
2634 size
= bdrv_getlength(s
->hd
);
2635 nb_clusters
= size_to_clusters(s
, size
);
2636 for(k
= 0; k
< nb_clusters
;) {
2638 refcount
= get_refcount(bs
, k
);
2640 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
2642 printf("%lld: refcount=%d nb=%lld\n", k
, refcount
, k
- k1
);
2648 BlockDriver bdrv_qcow2
= {
2649 .format_name
= "qcow2",
2650 .instance_size
= sizeof(BDRVQcowState
),
2651 .bdrv_probe
= qcow_probe
,
2652 .bdrv_open
= qcow_open
,
2653 .bdrv_close
= qcow_close
,
2654 .bdrv_create
= qcow_create
,
2655 .bdrv_flush
= qcow_flush
,
2656 .bdrv_is_allocated
= qcow_is_allocated
,
2657 .bdrv_set_key
= qcow_set_key
,
2658 .bdrv_make_empty
= qcow_make_empty
,
2660 .bdrv_aio_read
= qcow_aio_read
,
2661 .bdrv_aio_write
= qcow_aio_write
,
2662 .bdrv_aio_cancel
= qcow_aio_cancel
,
2663 .aiocb_size
= sizeof(QCowAIOCB
),
2664 .bdrv_write_compressed
= qcow_write_compressed
,
2666 .bdrv_snapshot_create
= qcow_snapshot_create
,
2667 .bdrv_snapshot_goto
= qcow_snapshot_goto
,
2668 .bdrv_snapshot_delete
= qcow_snapshot_delete
,
2669 .bdrv_snapshot_list
= qcow_snapshot_list
,
2670 .bdrv_get_info
= qcow_get_info
,