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));
263 if (bdrv_pread(s
->hd
, s
->l1_table_offset
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
264 s
->l1_size
* sizeof(uint64_t))
266 for(i
= 0;i
< s
->l1_size
; i
++) {
267 be64_to_cpus(&s
->l1_table
[i
]);
270 s
->l2_cache
= qemu_malloc(s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
273 s
->cluster_cache
= qemu_malloc(s
->cluster_size
);
274 if (!s
->cluster_cache
)
276 /* one more sector for decompressed data alignment */
277 s
->cluster_data
= qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_size
279 if (!s
->cluster_data
)
281 s
->cluster_cache_offset
= -1;
283 if (refcount_init(bs
) < 0)
286 scan_refcount(bs
, &s
->highest_alloc
);
288 /* read the backing file name */
289 if (header
.backing_file_offset
!= 0) {
290 len
= header
.backing_file_size
;
293 if (bdrv_pread(s
->hd
, header
.backing_file_offset
, bs
->backing_file
, len
) != len
)
295 bs
->backing_file
[len
] = '\0';
297 if (qcow_read_snapshots(bs
) < 0)
306 qcow_free_snapshots(bs
);
308 qemu_free(s
->l1_table
);
309 qemu_free(s
->l2_cache
);
310 qemu_free(s
->cluster_cache
);
311 qemu_free(s
->cluster_data
);
316 static int qcow_set_key(BlockDriverState
*bs
, const char *key
)
318 BDRVQcowState
*s
= bs
->opaque
;
322 memset(keybuf
, 0, 16);
326 /* XXX: we could compress the chars to 7 bits to increase
328 for(i
= 0;i
< len
;i
++) {
331 s
->crypt_method
= s
->crypt_method_header
;
333 if (AES_set_encrypt_key(keybuf
, 128, &s
->aes_encrypt_key
) != 0)
335 if (AES_set_decrypt_key(keybuf
, 128, &s
->aes_decrypt_key
) != 0)
345 AES_encrypt(in
, tmp
, &s
->aes_encrypt_key
);
346 AES_decrypt(tmp
, out
, &s
->aes_decrypt_key
);
347 for(i
= 0; i
< 16; i
++)
348 printf(" %02x", tmp
[i
]);
350 for(i
= 0; i
< 16; i
++)
351 printf(" %02x", out
[i
]);
358 /* The crypt function is compatible with the linux cryptoloop
359 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
361 static void encrypt_sectors(BDRVQcowState
*s
, int64_t sector_num
,
362 uint8_t *out_buf
, const uint8_t *in_buf
,
363 int nb_sectors
, int enc
,
372 for(i
= 0; i
< nb_sectors
; i
++) {
373 ivec
.ll
[0] = cpu_to_le64(sector_num
);
375 AES_cbc_encrypt(in_buf
, out_buf
, 512, key
,
383 static int copy_sectors(BlockDriverState
*bs
, uint64_t start_sect
,
384 uint64_t cluster_offset
, int n_start
, int n_end
)
386 BDRVQcowState
*s
= bs
->opaque
;
392 ret
= qcow_read(bs
, start_sect
+ n_start
, s
->cluster_data
, n
);
395 if (s
->crypt_method
) {
396 encrypt_sectors(s
, start_sect
+ n_start
,
398 s
->cluster_data
, n
, 1,
399 &s
->aes_encrypt_key
);
401 ret
= bdrv_write(s
->hd
, (cluster_offset
>> 9) + n_start
,
408 static void l2_cache_reset(BlockDriverState
*bs
)
410 BDRVQcowState
*s
= bs
->opaque
;
412 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
413 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
414 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
417 static inline int l2_cache_new_entry(BlockDriverState
*bs
)
419 BDRVQcowState
*s
= bs
->opaque
;
423 /* find a new entry in the least used one */
425 min_count
= 0xffffffff;
426 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
427 if (s
->l2_cache_counts
[i
] < min_count
) {
428 min_count
= s
->l2_cache_counts
[i
];
435 static int64_t align_offset(int64_t offset
, int n
)
437 offset
= (offset
+ n
- 1) & ~(n
- 1);
441 static int grow_l1_table(BlockDriverState
*bs
, int min_size
)
443 BDRVQcowState
*s
= bs
->opaque
;
444 int new_l1_size
, new_l1_size2
, ret
, i
;
445 uint64_t *new_l1_table
;
446 uint64_t new_l1_table_offset
;
449 new_l1_size
= s
->l1_size
;
450 if (min_size
<= new_l1_size
)
452 while (min_size
> new_l1_size
) {
453 new_l1_size
= (new_l1_size
* 3 + 1) / 2;
456 printf("grow l1_table from %d to %d\n", s
->l1_size
, new_l1_size
);
459 new_l1_size2
= sizeof(uint64_t) * new_l1_size
;
460 new_l1_table
= qemu_mallocz(new_l1_size2
);
463 memcpy(new_l1_table
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t));
465 /* write new table (align to cluster) */
466 new_l1_table_offset
= alloc_clusters(bs
, new_l1_size2
);
468 for(i
= 0; i
< s
->l1_size
; i
++)
469 new_l1_table
[i
] = cpu_to_be64(new_l1_table
[i
]);
470 ret
= bdrv_pwrite(s
->hd
, new_l1_table_offset
, new_l1_table
, new_l1_size2
);
471 if (ret
!= new_l1_size2
)
473 for(i
= 0; i
< s
->l1_size
; i
++)
474 new_l1_table
[i
] = be64_to_cpu(new_l1_table
[i
]);
477 cpu_to_be32w((uint32_t*)data
, new_l1_size
);
478 cpu_to_be64w((uint64_t*)(data
+ 4), new_l1_table_offset
);
479 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_size
), data
,
480 sizeof(data
)) != sizeof(data
))
482 qemu_free(s
->l1_table
);
483 free_clusters(bs
, s
->l1_table_offset
, s
->l1_size
* sizeof(uint64_t));
484 s
->l1_table_offset
= new_l1_table_offset
;
485 s
->l1_table
= new_l1_table
;
486 s
->l1_size
= new_l1_size
;
489 qemu_free(s
->l1_table
);
496 * seek l2_offset in the l2_cache table
497 * if not found, return NULL,
499 * increments the l2 cache hit count of the entry,
500 * if counter overflow, divide by two all counters
501 * return the pointer to the l2 cache entry
505 static uint64_t *seek_l2_table(BDRVQcowState
*s
, uint64_t l2_offset
)
509 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
510 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
511 /* increment the hit count */
512 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
513 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
514 s
->l2_cache_counts
[j
] >>= 1;
517 return s
->l2_cache
+ (i
<< s
->l2_bits
);
526 * Loads a L2 table into memory. If the table is in the cache, the cache
527 * is used; otherwise the L2 table is loaded from the image file.
529 * Returns a pointer to the L2 table on success, or NULL if the read from
530 * the image file failed.
533 static uint64_t *l2_load(BlockDriverState
*bs
, uint64_t l2_offset
)
535 BDRVQcowState
*s
= bs
->opaque
;
539 /* seek if the table for the given offset is in the cache */
541 l2_table
= seek_l2_table(s
, l2_offset
);
542 if (l2_table
!= NULL
)
545 /* not found: load a new entry in the least used one */
547 min_index
= l2_cache_new_entry(bs
);
548 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
549 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
550 s
->l2_size
* sizeof(uint64_t))
552 s
->l2_cache_offsets
[min_index
] = l2_offset
;
553 s
->l2_cache_counts
[min_index
] = 1;
561 * Allocate a new l2 entry in the file. If l1_index points to an already
562 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
563 * table) copy the contents of the old L2 table into the newly allocated one.
564 * Otherwise the new table is initialized with zeros.
568 static uint64_t *l2_allocate(BlockDriverState
*bs
, int l1_index
)
570 BDRVQcowState
*s
= bs
->opaque
;
572 uint64_t old_l2_offset
, tmp
;
573 uint64_t *l2_table
, l2_offset
;
575 old_l2_offset
= s
->l1_table
[l1_index
];
577 /* allocate a new l2 entry */
579 l2_offset
= alloc_clusters(bs
, s
->l2_size
* sizeof(uint64_t));
581 /* update the L1 entry */
583 s
->l1_table
[l1_index
] = l2_offset
| QCOW_OFLAG_COPIED
;
585 tmp
= cpu_to_be64(l2_offset
| QCOW_OFLAG_COPIED
);
586 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
+ l1_index
* sizeof(tmp
),
587 &tmp
, sizeof(tmp
)) != sizeof(tmp
))
590 /* allocate a new entry in the l2 cache */
592 min_index
= l2_cache_new_entry(bs
);
593 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
595 if (old_l2_offset
== 0) {
596 /* if there was no old l2 table, clear the new table */
597 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
599 /* if there was an old l2 table, read it from the disk */
600 if (bdrv_pread(s
->hd
, old_l2_offset
,
601 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
602 s
->l2_size
* sizeof(uint64_t))
605 /* write the l2 table to the file */
606 if (bdrv_pwrite(s
->hd
, l2_offset
,
607 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
608 s
->l2_size
* sizeof(uint64_t))
611 /* update the l2 cache entry */
613 s
->l2_cache_offsets
[min_index
] = l2_offset
;
614 s
->l2_cache_counts
[min_index
] = 1;
619 static int size_to_clusters(BDRVQcowState
*s
, int64_t size
)
621 return (size
+ (s
->cluster_size
- 1)) >> s
->cluster_bits
;
624 static int count_contiguous_clusters(uint64_t nb_clusters
, int cluster_size
,
625 uint64_t *l2_table
, uint64_t start
, uint64_t mask
)
628 uint64_t offset
= be64_to_cpu(l2_table
[0]) & ~mask
;
633 for (i
= start
; i
< start
+ nb_clusters
; i
++)
634 if (offset
+ i
* cluster_size
!= (be64_to_cpu(l2_table
[i
]) & ~mask
))
640 static int count_contiguous_free_clusters(uint64_t nb_clusters
, uint64_t *l2_table
)
644 while(nb_clusters
-- && l2_table
[i
] == 0)
653 * For a given offset of the disk image, return cluster offset in
656 * on entry, *num is the number of contiguous clusters we'd like to
657 * access following offset.
659 * on exit, *num is the number of contiguous clusters we can read.
661 * Return 1, if the offset is found
662 * Return 0, otherwise.
666 static uint64_t get_cluster_offset(BlockDriverState
*bs
,
667 uint64_t offset
, int *num
)
669 BDRVQcowState
*s
= bs
->opaque
;
670 int l1_index
, l2_index
;
671 uint64_t l2_offset
, *l2_table
, cluster_offset
;
673 int index_in_cluster
, nb_available
, nb_needed
, nb_clusters
;
675 index_in_cluster
= (offset
>> 9) & (s
->cluster_sectors
- 1);
676 nb_needed
= *num
+ index_in_cluster
;
678 l1_bits
= s
->l2_bits
+ s
->cluster_bits
;
680 /* compute how many bytes there are between the offset and
681 * the end of the l1 entry
684 nb_available
= (1 << l1_bits
) - (offset
& ((1 << l1_bits
) - 1));
686 /* compute the number of available sectors */
688 nb_available
= (nb_available
>> 9) + index_in_cluster
;
692 /* seek the the l2 offset in the l1 table */
694 l1_index
= offset
>> l1_bits
;
695 if (l1_index
>= s
->l1_size
)
698 l2_offset
= s
->l1_table
[l1_index
];
700 /* seek the l2 table of the given l2 offset */
705 /* load the l2 table in memory */
707 l2_offset
&= ~QCOW_OFLAG_COPIED
;
708 l2_table
= l2_load(bs
, l2_offset
);
709 if (l2_table
== NULL
)
712 /* find the cluster offset for the given disk offset */
714 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
715 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
716 nb_clusters
= size_to_clusters(s
, nb_needed
<< 9);
718 if (!cluster_offset
) {
719 /* how many empty clusters ? */
720 c
= count_contiguous_free_clusters(nb_clusters
, &l2_table
[l2_index
]);
722 /* how many allocated clusters ? */
723 c
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
724 &l2_table
[l2_index
], 0, QCOW_OFLAG_COPIED
);
727 nb_available
= (c
* s
->cluster_sectors
);
729 if (nb_available
> nb_needed
)
730 nb_available
= nb_needed
;
732 *num
= nb_available
- index_in_cluster
;
734 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
740 * free clusters according to its type: compressed or not
744 static void free_any_clusters(BlockDriverState
*bs
,
745 uint64_t cluster_offset
, int nb_clusters
)
747 BDRVQcowState
*s
= bs
->opaque
;
749 /* free the cluster */
751 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
753 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) &
755 free_clusters(bs
, (cluster_offset
& s
->cluster_offset_mask
) & ~511,
760 free_clusters(bs
, cluster_offset
, nb_clusters
<< s
->cluster_bits
);
768 * for a given disk offset, load (and allocate if needed)
771 * the l2 table offset in the qcow2 file and the cluster index
772 * in the l2 table are given to the caller.
776 static int get_cluster_table(BlockDriverState
*bs
, uint64_t offset
,
777 uint64_t **new_l2_table
,
778 uint64_t *new_l2_offset
,
781 BDRVQcowState
*s
= bs
->opaque
;
782 int l1_index
, l2_index
, ret
;
783 uint64_t l2_offset
, *l2_table
;
785 /* seek the the l2 offset in the l1 table */
787 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
788 if (l1_index
>= s
->l1_size
) {
789 ret
= grow_l1_table(bs
, l1_index
+ 1);
793 l2_offset
= s
->l1_table
[l1_index
];
795 /* seek the l2 table of the given l2 offset */
797 if (l2_offset
& QCOW_OFLAG_COPIED
) {
798 /* load the l2 table in memory */
799 l2_offset
&= ~QCOW_OFLAG_COPIED
;
800 l2_table
= l2_load(bs
, l2_offset
);
801 if (l2_table
== NULL
)
805 free_clusters(bs
, l2_offset
, s
->l2_size
* sizeof(uint64_t));
806 l2_table
= l2_allocate(bs
, l1_index
);
807 if (l2_table
== NULL
)
809 l2_offset
= s
->l1_table
[l1_index
] & ~QCOW_OFLAG_COPIED
;
812 /* find the cluster offset for the given disk offset */
814 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
816 *new_l2_table
= l2_table
;
817 *new_l2_offset
= l2_offset
;
818 *new_l2_index
= l2_index
;
824 * alloc_compressed_cluster_offset
826 * For a given offset of the disk image, return cluster offset in
829 * If the offset is not found, allocate a new compressed cluster.
831 * Return the cluster offset if successful,
832 * Return 0, otherwise.
836 static uint64_t alloc_compressed_cluster_offset(BlockDriverState
*bs
,
840 BDRVQcowState
*s
= bs
->opaque
;
842 uint64_t l2_offset
, *l2_table
, cluster_offset
;
845 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
849 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
850 if (cluster_offset
& QCOW_OFLAG_COPIED
)
851 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
854 free_any_clusters(bs
, cluster_offset
, 1);
856 cluster_offset
= alloc_bytes(bs
, compressed_size
);
857 nb_csectors
= ((cluster_offset
+ compressed_size
- 1) >> 9) -
858 (cluster_offset
>> 9);
860 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
861 ((uint64_t)nb_csectors
<< s
->csize_shift
);
863 /* update L2 table */
865 /* compressed clusters never have the copied flag */
867 l2_table
[l2_index
] = cpu_to_be64(cluster_offset
);
868 if (bdrv_pwrite(s
->hd
,
869 l2_offset
+ l2_index
* sizeof(uint64_t),
871 sizeof(uint64_t)) != sizeof(uint64_t))
874 return cluster_offset
;
877 typedef struct QCowL2Meta
885 static int alloc_cluster_link_l2(BlockDriverState
*bs
, uint64_t cluster_offset
,
888 BDRVQcowState
*s
= bs
->opaque
;
889 int i
, j
= 0, l2_index
, ret
;
890 uint64_t *old_cluster
, start_sect
, l2_offset
, *l2_table
;
892 if (m
->nb_clusters
== 0)
895 if (!(old_cluster
= qemu_malloc(m
->nb_clusters
* sizeof(uint64_t))))
898 /* copy content of unmodified sectors */
899 start_sect
= (m
->offset
& ~(s
->cluster_size
- 1)) >> 9;
901 ret
= copy_sectors(bs
, start_sect
, cluster_offset
, 0, m
->n_start
);
906 if (m
->nb_available
& (s
->cluster_sectors
- 1)) {
907 uint64_t end
= m
->nb_available
& ~(uint64_t)(s
->cluster_sectors
- 1);
908 ret
= copy_sectors(bs
, start_sect
+ end
, cluster_offset
+ (end
<< 9),
909 m
->nb_available
- end
, s
->cluster_sectors
);
915 /* update L2 table */
916 if (!get_cluster_table(bs
, m
->offset
, &l2_table
, &l2_offset
, &l2_index
))
919 for (i
= 0; i
< m
->nb_clusters
; i
++) {
920 if(l2_table
[l2_index
+ i
] != 0)
921 old_cluster
[j
++] = l2_table
[l2_index
+ i
];
923 l2_table
[l2_index
+ i
] = cpu_to_be64((cluster_offset
+
924 (i
<< s
->cluster_bits
)) | QCOW_OFLAG_COPIED
);
927 if (bdrv_pwrite(s
->hd
, l2_offset
+ l2_index
* sizeof(uint64_t),
928 l2_table
+ l2_index
, m
->nb_clusters
* sizeof(uint64_t)) !=
929 m
->nb_clusters
* sizeof(uint64_t))
932 for (i
= 0; i
< j
; i
++)
933 free_any_clusters(bs
, old_cluster
[i
], 1);
937 qemu_free(old_cluster
);
942 * alloc_cluster_offset
944 * For a given offset of the disk image, return cluster offset in
947 * If the offset is not found, allocate a new cluster.
949 * Return the cluster offset if successful,
950 * Return 0, otherwise.
954 static uint64_t alloc_cluster_offset(BlockDriverState
*bs
,
956 int n_start
, int n_end
,
957 int *num
, QCowL2Meta
*m
)
959 BDRVQcowState
*s
= bs
->opaque
;
961 uint64_t l2_offset
, *l2_table
, cluster_offset
;
962 int nb_clusters
, i
= 0;
964 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
968 nb_clusters
= size_to_clusters(s
, n_end
<< 9);
970 nb_clusters
= MIN(nb_clusters
, s
->l2_size
- l2_index
);
972 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
974 /* We keep all QCOW_OFLAG_COPIED clusters */
976 if (cluster_offset
& QCOW_OFLAG_COPIED
) {
977 nb_clusters
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
978 &l2_table
[l2_index
], 0, 0);
980 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
986 /* for the moment, multiple compressed clusters are not managed */
988 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
)
991 /* how many available clusters ? */
993 while (i
< nb_clusters
) {
994 i
+= count_contiguous_clusters(nb_clusters
- i
, s
->cluster_size
,
995 &l2_table
[l2_index
], i
, 0);
997 if(be64_to_cpu(l2_table
[l2_index
+ i
]))
1000 i
+= count_contiguous_free_clusters(nb_clusters
- i
,
1001 &l2_table
[l2_index
+ i
]);
1003 cluster_offset
= be64_to_cpu(l2_table
[l2_index
+ i
]);
1005 if ((cluster_offset
& QCOW_OFLAG_COPIED
) ||
1006 (cluster_offset
& QCOW_OFLAG_COMPRESSED
))
1011 /* allocate a new cluster */
1013 cluster_offset
= alloc_clusters(bs
, nb_clusters
* s
->cluster_size
);
1015 /* save info needed for meta data update */
1017 m
->n_start
= n_start
;
1018 m
->nb_clusters
= nb_clusters
;
1021 m
->nb_available
= MIN(nb_clusters
<< (s
->cluster_bits
- 9), n_end
);
1023 *num
= m
->nb_available
- n_start
;
1025 return cluster_offset
;
1028 static int qcow_is_allocated(BlockDriverState
*bs
, int64_t sector_num
,
1029 int nb_sectors
, int *pnum
)
1031 uint64_t cluster_offset
;
1034 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, pnum
);
1036 return (cluster_offset
!= 0);
1039 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
1040 const uint8_t *buf
, int buf_size
)
1042 z_stream strm1
, *strm
= &strm1
;
1045 memset(strm
, 0, sizeof(*strm
));
1047 strm
->next_in
= (uint8_t *)buf
;
1048 strm
->avail_in
= buf_size
;
1049 strm
->next_out
= out_buf
;
1050 strm
->avail_out
= out_buf_size
;
1052 ret
= inflateInit2(strm
, -12);
1055 ret
= inflate(strm
, Z_FINISH
);
1056 out_len
= strm
->next_out
- out_buf
;
1057 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
1058 out_len
!= out_buf_size
) {
1066 static int decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
)
1068 int ret
, csize
, nb_csectors
, sector_offset
;
1071 coffset
= cluster_offset
& s
->cluster_offset_mask
;
1072 if (s
->cluster_cache_offset
!= coffset
) {
1073 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
1074 sector_offset
= coffset
& 511;
1075 csize
= nb_csectors
* 512 - sector_offset
;
1076 ret
= bdrv_read(s
->hd
, coffset
>> 9, s
->cluster_data
, nb_csectors
);
1080 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
1081 s
->cluster_data
+ sector_offset
, csize
) < 0) {
1084 s
->cluster_cache_offset
= coffset
;
1089 /* handle reading after the end of the backing file */
1090 static int backing_read1(BlockDriverState
*bs
,
1091 int64_t sector_num
, uint8_t *buf
, int nb_sectors
)
1094 if ((sector_num
+ nb_sectors
) <= bs
->total_sectors
)
1096 if (sector_num
>= bs
->total_sectors
)
1099 n1
= bs
->total_sectors
- sector_num
;
1100 memset(buf
+ n1
* 512, 0, 512 * (nb_sectors
- n1
));
1104 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
1105 uint8_t *buf
, int nb_sectors
)
1107 BDRVQcowState
*s
= bs
->opaque
;
1108 int ret
, index_in_cluster
, n
, n1
;
1109 uint64_t cluster_offset
;
1111 while (nb_sectors
> 0) {
1113 cluster_offset
= get_cluster_offset(bs
, sector_num
<< 9, &n
);
1114 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1115 if (!cluster_offset
) {
1116 if (bs
->backing_hd
) {
1117 /* read from the base image */
1118 n1
= backing_read1(bs
->backing_hd
, sector_num
, buf
, n
);
1120 ret
= bdrv_read(bs
->backing_hd
, sector_num
, buf
, n1
);
1125 memset(buf
, 0, 512 * n
);
1127 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1128 if (decompress_cluster(s
, cluster_offset
) < 0)
1130 memcpy(buf
, s
->cluster_cache
+ index_in_cluster
* 512, 512 * n
);
1132 ret
= bdrv_pread(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1135 if (s
->crypt_method
) {
1136 encrypt_sectors(s
, sector_num
, buf
, buf
, n
, 0,
1137 &s
->aes_decrypt_key
);
1147 static int qcow_write(BlockDriverState
*bs
, int64_t sector_num
,
1148 const uint8_t *buf
, int nb_sectors
)
1150 BDRVQcowState
*s
= bs
->opaque
;
1151 int ret
, index_in_cluster
, n
;
1152 uint64_t cluster_offset
;
1156 while (nb_sectors
> 0) {
1157 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
1158 n_end
= index_in_cluster
+ nb_sectors
;
1159 if (s
->crypt_method
&&
1160 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1161 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1162 cluster_offset
= alloc_cluster_offset(bs
, sector_num
<< 9,
1164 n_end
, &n
, &l2meta
);
1165 if (!cluster_offset
)
1167 if (s
->crypt_method
) {
1168 encrypt_sectors(s
, sector_num
, s
->cluster_data
, buf
, n
, 1,
1169 &s
->aes_encrypt_key
);
1170 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512,
1171 s
->cluster_data
, n
* 512);
1173 ret
= bdrv_pwrite(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
1175 if (ret
!= n
* 512 || alloc_cluster_link_l2(bs
, cluster_offset
, &l2meta
) < 0) {
1176 free_any_clusters(bs
, cluster_offset
, l2meta
.nb_clusters
);
1183 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1187 typedef struct QCowAIOCB
{
1188 BlockDriverAIOCB common
;
1193 uint64_t cluster_offset
;
1194 uint8_t *cluster_data
;
1195 BlockDriverAIOCB
*hd_aiocb
;
1200 static void qcow_aio_read_cb(void *opaque
, int ret
);
1201 static void qcow_aio_read_bh(void *opaque
)
1203 QCowAIOCB
*acb
= opaque
;
1204 qemu_bh_delete(acb
->bh
);
1206 qcow_aio_read_cb(opaque
, 0);
1209 static int qcow_schedule_bh(QEMUBHFunc
*cb
, QCowAIOCB
*acb
)
1214 acb
->bh
= qemu_bh_new(cb
, acb
);
1218 qemu_bh_schedule(acb
->bh
);
1223 static void qcow_aio_read_cb(void *opaque
, int ret
)
1225 QCowAIOCB
*acb
= opaque
;
1226 BlockDriverState
*bs
= acb
->common
.bs
;
1227 BDRVQcowState
*s
= bs
->opaque
;
1228 int index_in_cluster
, n1
;
1230 acb
->hd_aiocb
= NULL
;
1233 acb
->common
.cb(acb
->common
.opaque
, ret
);
1234 qemu_aio_release(acb
);
1238 /* post process the read buffer */
1239 if (!acb
->cluster_offset
) {
1241 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1244 if (s
->crypt_method
) {
1245 encrypt_sectors(s
, acb
->sector_num
, acb
->buf
, acb
->buf
,
1247 &s
->aes_decrypt_key
);
1251 acb
->nb_sectors
-= acb
->n
;
1252 acb
->sector_num
+= acb
->n
;
1253 acb
->buf
+= acb
->n
* 512;
1255 if (acb
->nb_sectors
== 0) {
1256 /* request completed */
1257 acb
->common
.cb(acb
->common
.opaque
, 0);
1258 qemu_aio_release(acb
);
1262 /* prepare next AIO request */
1263 acb
->n
= acb
->nb_sectors
;
1264 acb
->cluster_offset
= get_cluster_offset(bs
, acb
->sector_num
<< 9, &acb
->n
);
1265 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1267 if (!acb
->cluster_offset
) {
1268 if (bs
->backing_hd
) {
1269 /* read from the base image */
1270 n1
= backing_read1(bs
->backing_hd
, acb
->sector_num
,
1273 acb
->hd_aiocb
= bdrv_aio_read(bs
->backing_hd
, acb
->sector_num
,
1274 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1275 if (acb
->hd_aiocb
== NULL
)
1278 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1283 /* Note: in this case, no need to wait */
1284 memset(acb
->buf
, 0, 512 * acb
->n
);
1285 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1289 } else if (acb
->cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
1290 /* add AIO support for compressed blocks ? */
1291 if (decompress_cluster(s
, acb
->cluster_offset
) < 0)
1294 s
->cluster_cache
+ index_in_cluster
* 512, 512 * acb
->n
);
1295 ret
= qcow_schedule_bh(qcow_aio_read_bh
, acb
);
1299 if ((acb
->cluster_offset
& 511) != 0) {
1303 acb
->hd_aiocb
= bdrv_aio_read(s
->hd
,
1304 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1305 acb
->buf
, acb
->n
, qcow_aio_read_cb
, acb
);
1306 if (acb
->hd_aiocb
== NULL
)
1311 static QCowAIOCB
*qcow_aio_setup(BlockDriverState
*bs
,
1312 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1313 BlockDriverCompletionFunc
*cb
, void *opaque
)
1317 acb
= qemu_aio_get(bs
, cb
, opaque
);
1320 acb
->hd_aiocb
= NULL
;
1321 acb
->sector_num
= sector_num
;
1323 acb
->nb_sectors
= nb_sectors
;
1325 acb
->cluster_offset
= 0;
1326 acb
->l2meta
.nb_clusters
= 0;
1330 static BlockDriverAIOCB
*qcow_aio_read(BlockDriverState
*bs
,
1331 int64_t sector_num
, uint8_t *buf
, int nb_sectors
,
1332 BlockDriverCompletionFunc
*cb
, void *opaque
)
1336 acb
= qcow_aio_setup(bs
, sector_num
, buf
, nb_sectors
, cb
, opaque
);
1340 qcow_aio_read_cb(acb
, 0);
1341 return &acb
->common
;
1344 static void qcow_aio_write_cb(void *opaque
, int ret
)
1346 QCowAIOCB
*acb
= opaque
;
1347 BlockDriverState
*bs
= acb
->common
.bs
;
1348 BDRVQcowState
*s
= bs
->opaque
;
1349 int index_in_cluster
;
1350 const uint8_t *src_buf
;
1353 acb
->hd_aiocb
= NULL
;
1357 acb
->common
.cb(acb
->common
.opaque
, ret
);
1358 qemu_aio_release(acb
);
1362 if (alloc_cluster_link_l2(bs
, acb
->cluster_offset
, &acb
->l2meta
) < 0) {
1363 free_any_clusters(bs
, acb
->cluster_offset
, acb
->l2meta
.nb_clusters
);
1367 acb
->nb_sectors
-= acb
->n
;
1368 acb
->sector_num
+= acb
->n
;
1369 acb
->buf
+= acb
->n
* 512;
1371 if (acb
->nb_sectors
== 0) {
1372 /* request completed */
1373 acb
->common
.cb(acb
->common
.opaque
, 0);
1374 qemu_aio_release(acb
);
1378 index_in_cluster
= acb
->sector_num
& (s
->cluster_sectors
- 1);
1379 n_end
= index_in_cluster
+ acb
->nb_sectors
;
1380 if (s
->crypt_method
&&
1381 n_end
> QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
)
1382 n_end
= QCOW_MAX_CRYPT_CLUSTERS
* s
->cluster_sectors
;
1384 acb
->cluster_offset
= alloc_cluster_offset(bs
, acb
->sector_num
<< 9,
1386 n_end
, &acb
->n
, &acb
->l2meta
);
1387 if (!acb
->cluster_offset
|| (acb
->cluster_offset
& 511) != 0) {
1391 if (s
->crypt_method
) {
1392 if (!acb
->cluster_data
) {
1393 acb
->cluster_data
= qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS
*
1395 if (!acb
->cluster_data
) {
1400 encrypt_sectors(s
, acb
->sector_num
, acb
->cluster_data
, acb
->buf
,
1401 acb
->n
, 1, &s
->aes_encrypt_key
);
1402 src_buf
= acb
->cluster_data
;
1406 acb
->hd_aiocb
= bdrv_aio_write(s
->hd
,
1407 (acb
->cluster_offset
>> 9) + index_in_cluster
,
1409 qcow_aio_write_cb
, acb
);
1410 if (acb
->hd_aiocb
== NULL
)
1414 static BlockDriverAIOCB
*qcow_aio_write(BlockDriverState
*bs
,
1415 int64_t sector_num
, const uint8_t *buf
, int nb_sectors
,
1416 BlockDriverCompletionFunc
*cb
, void *opaque
)
1418 BDRVQcowState
*s
= bs
->opaque
;
1421 s
->cluster_cache_offset
= -1; /* disable compressed cache */
1423 acb
= qcow_aio_setup(bs
, sector_num
, (uint8_t*)buf
, nb_sectors
, cb
, opaque
);
1427 qcow_aio_write_cb(acb
, 0);
1428 return &acb
->common
;
1431 static void qcow_aio_cancel(BlockDriverAIOCB
*blockacb
)
1433 QCowAIOCB
*acb
= (QCowAIOCB
*)blockacb
;
1435 bdrv_aio_cancel(acb
->hd_aiocb
);
1436 qemu_aio_release(acb
);
1439 static void qcow_close(BlockDriverState
*bs
)
1441 BDRVQcowState
*s
= bs
->opaque
;
1442 qemu_free(s
->l1_table
);
1443 qemu_free(s
->l2_cache
);
1444 qemu_free(s
->cluster_cache
);
1445 qemu_free(s
->cluster_data
);
1450 /* XXX: use std qcow open function ? */
1451 typedef struct QCowCreateState
{
1454 uint16_t *refcount_block
;
1455 uint64_t *refcount_table
;
1456 int64_t l1_table_offset
;
1457 int64_t refcount_table_offset
;
1458 int64_t refcount_block_offset
;
1461 static void create_refcount_update(QCowCreateState
*s
,
1462 int64_t offset
, int64_t size
)
1465 int64_t start
, last
, cluster_offset
;
1468 start
= offset
& ~(s
->cluster_size
- 1);
1469 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
1470 for(cluster_offset
= start
; cluster_offset
<= last
;
1471 cluster_offset
+= s
->cluster_size
) {
1472 p
= &s
->refcount_block
[cluster_offset
>> s
->cluster_bits
];
1473 refcount
= be16_to_cpu(*p
);
1475 *p
= cpu_to_be16(refcount
);
1479 static int qcow_create(const char *filename
, int64_t total_size
,
1480 const char *backing_file
, int flags
)
1482 int fd
, header_size
, backing_filename_len
, l1_size
, i
, shift
, l2_bits
;
1484 uint64_t tmp
, offset
;
1485 QCowCreateState s1
, *s
= &s1
;
1487 memset(s
, 0, sizeof(*s
));
1489 fd
= open(filename
, O_WRONLY
| O_CREAT
| O_TRUNC
| O_BINARY
, 0644);
1492 memset(&header
, 0, sizeof(header
));
1493 header
.magic
= cpu_to_be32(QCOW_MAGIC
);
1494 header
.version
= cpu_to_be32(QCOW_VERSION
);
1495 header
.size
= cpu_to_be64(total_size
* 512);
1496 header_size
= sizeof(header
);
1497 backing_filename_len
= 0;
1499 header
.backing_file_offset
= cpu_to_be64(header_size
);
1500 backing_filename_len
= strlen(backing_file
);
1501 header
.backing_file_size
= cpu_to_be32(backing_filename_len
);
1502 header_size
+= backing_filename_len
;
1504 s
->cluster_bits
= 12; /* 4 KB clusters */
1505 s
->cluster_size
= 1 << s
->cluster_bits
;
1506 header
.cluster_bits
= cpu_to_be32(s
->cluster_bits
);
1507 header_size
= (header_size
+ 7) & ~7;
1508 if (flags
& BLOCK_FLAG_ENCRYPT
) {
1509 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_AES
);
1511 header
.crypt_method
= cpu_to_be32(QCOW_CRYPT_NONE
);
1513 l2_bits
= s
->cluster_bits
- 3;
1514 shift
= s
->cluster_bits
+ l2_bits
;
1515 l1_size
= (((total_size
* 512) + (1LL << shift
) - 1) >> shift
);
1516 offset
= align_offset(header_size
, s
->cluster_size
);
1517 s
->l1_table_offset
= offset
;
1518 header
.l1_table_offset
= cpu_to_be64(s
->l1_table_offset
);
1519 header
.l1_size
= cpu_to_be32(l1_size
);
1520 offset
+= align_offset(l1_size
* sizeof(uint64_t), s
->cluster_size
);
1522 s
->refcount_table
= qemu_mallocz(s
->cluster_size
);
1523 if (!s
->refcount_table
)
1525 s
->refcount_block
= qemu_mallocz(s
->cluster_size
);
1526 if (!s
->refcount_block
)
1529 s
->refcount_table_offset
= offset
;
1530 header
.refcount_table_offset
= cpu_to_be64(offset
);
1531 header
.refcount_table_clusters
= cpu_to_be32(1);
1532 offset
+= s
->cluster_size
;
1534 s
->refcount_table
[0] = cpu_to_be64(offset
);
1535 s
->refcount_block_offset
= offset
;
1536 offset
+= s
->cluster_size
;
1538 /* update refcounts */
1539 create_refcount_update(s
, 0, header_size
);
1540 create_refcount_update(s
, s
->l1_table_offset
, l1_size
* sizeof(uint64_t));
1541 create_refcount_update(s
, s
->refcount_table_offset
, s
->cluster_size
);
1542 create_refcount_update(s
, s
->refcount_block_offset
, s
->cluster_size
);
1544 /* write all the data */
1545 write(fd
, &header
, sizeof(header
));
1547 write(fd
, backing_file
, backing_filename_len
);
1549 lseek(fd
, s
->l1_table_offset
, SEEK_SET
);
1551 for(i
= 0;i
< l1_size
; i
++) {
1552 write(fd
, &tmp
, sizeof(tmp
));
1554 lseek(fd
, s
->refcount_table_offset
, SEEK_SET
);
1555 write(fd
, s
->refcount_table
, s
->cluster_size
);
1557 lseek(fd
, s
->refcount_block_offset
, SEEK_SET
);
1558 write(fd
, s
->refcount_block
, s
->cluster_size
);
1560 qemu_free(s
->refcount_table
);
1561 qemu_free(s
->refcount_block
);
1565 qemu_free(s
->refcount_table
);
1566 qemu_free(s
->refcount_block
);
1571 static int qcow_make_empty(BlockDriverState
*bs
)
1574 /* XXX: not correct */
1575 BDRVQcowState
*s
= bs
->opaque
;
1576 uint32_t l1_length
= s
->l1_size
* sizeof(uint64_t);
1579 memset(s
->l1_table
, 0, l1_length
);
1580 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
, s
->l1_table
, l1_length
) < 0)
1582 ret
= bdrv_truncate(s
->hd
, s
->l1_table_offset
+ l1_length
);
1591 /* XXX: put compressed sectors first, then all the cluster aligned
1592 tables to avoid losing bytes in alignment */
1593 static int qcow_write_compressed(BlockDriverState
*bs
, int64_t sector_num
,
1594 const uint8_t *buf
, int nb_sectors
)
1596 BDRVQcowState
*s
= bs
->opaque
;
1600 uint64_t cluster_offset
;
1602 if (nb_sectors
== 0) {
1603 /* align end of file to a sector boundary to ease reading with
1604 sector based I/Os */
1605 cluster_offset
= bdrv_getlength(s
->hd
);
1606 cluster_offset
= (cluster_offset
+ 511) & ~511;
1607 bdrv_truncate(s
->hd
, cluster_offset
);
1611 if (nb_sectors
!= s
->cluster_sectors
)
1614 out_buf
= qemu_malloc(s
->cluster_size
+ (s
->cluster_size
/ 1000) + 128);
1618 /* best compression, small window, no zlib header */
1619 memset(&strm
, 0, sizeof(strm
));
1620 ret
= deflateInit2(&strm
, Z_DEFAULT_COMPRESSION
,
1622 9, Z_DEFAULT_STRATEGY
);
1628 strm
.avail_in
= s
->cluster_size
;
1629 strm
.next_in
= (uint8_t *)buf
;
1630 strm
.avail_out
= s
->cluster_size
;
1631 strm
.next_out
= out_buf
;
1633 ret
= deflate(&strm
, Z_FINISH
);
1634 if (ret
!= Z_STREAM_END
&& ret
!= Z_OK
) {
1639 out_len
= strm
.next_out
- out_buf
;
1643 if (ret
!= Z_STREAM_END
|| out_len
>= s
->cluster_size
) {
1644 /* could not compress: write normal cluster */
1645 qcow_write(bs
, sector_num
, buf
, s
->cluster_sectors
);
1647 cluster_offset
= alloc_compressed_cluster_offset(bs
, sector_num
<< 9,
1649 if (!cluster_offset
)
1651 cluster_offset
&= s
->cluster_offset_mask
;
1652 if (bdrv_pwrite(s
->hd
, cluster_offset
, out_buf
, out_len
) != out_len
) {
1662 static void qcow_flush(BlockDriverState
*bs
)
1664 BDRVQcowState
*s
= bs
->opaque
;
1668 static int qcow_get_info(BlockDriverState
*bs
, BlockDriverInfo
*bdi
)
1670 BDRVQcowState
*s
= bs
->opaque
;
1671 bdi
->cluster_size
= s
->cluster_size
;
1672 bdi
->vm_state_offset
= (int64_t)s
->l1_vm_state_index
<<
1673 (s
->cluster_bits
+ s
->l2_bits
);
1674 bdi
->highest_alloc
= s
->highest_alloc
<< s
->cluster_bits
;
1678 /*********************************************************/
1679 /* snapshot support */
1681 /* update the refcounts of snapshots and the copied flag */
1682 static int update_snapshot_refcount(BlockDriverState
*bs
,
1683 int64_t l1_table_offset
,
1687 BDRVQcowState
*s
= bs
->opaque
;
1688 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
, l1_allocated
;
1689 int64_t old_offset
, old_l2_offset
;
1690 int l2_size
, i
, j
, l1_modified
, l2_modified
, nb_csectors
, refcount
;
1696 l1_size2
= l1_size
* sizeof(uint64_t);
1698 if (l1_table_offset
!= s
->l1_table_offset
) {
1699 l1_table
= qemu_malloc(l1_size2
);
1703 if (bdrv_pread(s
->hd
, l1_table_offset
,
1704 l1_table
, l1_size2
) != l1_size2
)
1706 for(i
= 0;i
< l1_size
; i
++)
1707 be64_to_cpus(&l1_table
[i
]);
1709 assert(l1_size
== s
->l1_size
);
1710 l1_table
= s
->l1_table
;
1714 l2_size
= s
->l2_size
* sizeof(uint64_t);
1715 l2_table
= qemu_malloc(l2_size
);
1719 for(i
= 0; i
< l1_size
; i
++) {
1720 l2_offset
= l1_table
[i
];
1722 old_l2_offset
= l2_offset
;
1723 l2_offset
&= ~QCOW_OFLAG_COPIED
;
1725 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
1727 for(j
= 0; j
< s
->l2_size
; j
++) {
1728 offset
= be64_to_cpu(l2_table
[j
]);
1730 old_offset
= offset
;
1731 offset
&= ~QCOW_OFLAG_COPIED
;
1732 if (offset
& QCOW_OFLAG_COMPRESSED
) {
1733 nb_csectors
= ((offset
>> s
->csize_shift
) &
1736 update_refcount(bs
, (offset
& s
->cluster_offset_mask
) & ~511,
1737 nb_csectors
* 512, addend
);
1738 /* compressed clusters are never modified */
1742 refcount
= update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, addend
);
1744 refcount
= get_refcount(bs
, offset
>> s
->cluster_bits
);
1748 if (refcount
== 1) {
1749 offset
|= QCOW_OFLAG_COPIED
;
1751 if (offset
!= old_offset
) {
1752 l2_table
[j
] = cpu_to_be64(offset
);
1758 if (bdrv_pwrite(s
->hd
,
1759 l2_offset
, l2_table
, l2_size
) != l2_size
)
1764 refcount
= update_cluster_refcount(bs
, l2_offset
>> s
->cluster_bits
, addend
);
1766 refcount
= get_refcount(bs
, l2_offset
>> s
->cluster_bits
);
1768 if (refcount
== 1) {
1769 l2_offset
|= QCOW_OFLAG_COPIED
;
1771 if (l2_offset
!= old_l2_offset
) {
1772 l1_table
[i
] = l2_offset
;
1778 for(i
= 0; i
< l1_size
; i
++)
1779 cpu_to_be64s(&l1_table
[i
]);
1780 if (bdrv_pwrite(s
->hd
, l1_table_offset
, l1_table
,
1781 l1_size2
) != l1_size2
)
1783 for(i
= 0; i
< l1_size
; i
++)
1784 be64_to_cpus(&l1_table
[i
]);
1787 qemu_free(l1_table
);
1788 qemu_free(l2_table
);
1792 qemu_free(l1_table
);
1793 qemu_free(l2_table
);
1797 static void qcow_free_snapshots(BlockDriverState
*bs
)
1799 BDRVQcowState
*s
= bs
->opaque
;
1802 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1803 qemu_free(s
->snapshots
[i
].name
);
1804 qemu_free(s
->snapshots
[i
].id_str
);
1806 qemu_free(s
->snapshots
);
1807 s
->snapshots
= NULL
;
1808 s
->nb_snapshots
= 0;
1811 static int qcow_read_snapshots(BlockDriverState
*bs
)
1813 BDRVQcowState
*s
= bs
->opaque
;
1814 QCowSnapshotHeader h
;
1816 int i
, id_str_size
, name_size
;
1818 uint32_t extra_data_size
;
1820 if (!s
->nb_snapshots
) {
1821 s
->snapshots
= NULL
;
1822 s
->snapshots_size
= 0;
1826 offset
= s
->snapshots_offset
;
1827 s
->snapshots
= qemu_mallocz(s
->nb_snapshots
* sizeof(QCowSnapshot
));
1830 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1831 offset
= align_offset(offset
, 8);
1832 if (bdrv_pread(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1834 offset
+= sizeof(h
);
1835 sn
= s
->snapshots
+ i
;
1836 sn
->l1_table_offset
= be64_to_cpu(h
.l1_table_offset
);
1837 sn
->l1_size
= be32_to_cpu(h
.l1_size
);
1838 sn
->vm_state_size
= be32_to_cpu(h
.vm_state_size
);
1839 sn
->date_sec
= be32_to_cpu(h
.date_sec
);
1840 sn
->date_nsec
= be32_to_cpu(h
.date_nsec
);
1841 sn
->vm_clock_nsec
= be64_to_cpu(h
.vm_clock_nsec
);
1842 extra_data_size
= be32_to_cpu(h
.extra_data_size
);
1844 id_str_size
= be16_to_cpu(h
.id_str_size
);
1845 name_size
= be16_to_cpu(h
.name_size
);
1847 offset
+= extra_data_size
;
1849 sn
->id_str
= qemu_malloc(id_str_size
+ 1);
1852 if (bdrv_pread(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1854 offset
+= id_str_size
;
1855 sn
->id_str
[id_str_size
] = '\0';
1857 sn
->name
= qemu_malloc(name_size
+ 1);
1860 if (bdrv_pread(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1862 offset
+= name_size
;
1863 sn
->name
[name_size
] = '\0';
1865 s
->snapshots_size
= offset
- s
->snapshots_offset
;
1868 qcow_free_snapshots(bs
);
1872 /* add at the end of the file a new list of snapshots */
1873 static int qcow_write_snapshots(BlockDriverState
*bs
)
1875 BDRVQcowState
*s
= bs
->opaque
;
1877 QCowSnapshotHeader h
;
1878 int i
, name_size
, id_str_size
, snapshots_size
;
1881 int64_t offset
, snapshots_offset
;
1883 /* compute the size of the snapshots */
1885 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1886 sn
= s
->snapshots
+ i
;
1887 offset
= align_offset(offset
, 8);
1888 offset
+= sizeof(h
);
1889 offset
+= strlen(sn
->id_str
);
1890 offset
+= strlen(sn
->name
);
1892 snapshots_size
= offset
;
1894 snapshots_offset
= alloc_clusters(bs
, snapshots_size
);
1895 offset
= snapshots_offset
;
1897 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1898 sn
= s
->snapshots
+ i
;
1899 memset(&h
, 0, sizeof(h
));
1900 h
.l1_table_offset
= cpu_to_be64(sn
->l1_table_offset
);
1901 h
.l1_size
= cpu_to_be32(sn
->l1_size
);
1902 h
.vm_state_size
= cpu_to_be32(sn
->vm_state_size
);
1903 h
.date_sec
= cpu_to_be32(sn
->date_sec
);
1904 h
.date_nsec
= cpu_to_be32(sn
->date_nsec
);
1905 h
.vm_clock_nsec
= cpu_to_be64(sn
->vm_clock_nsec
);
1907 id_str_size
= strlen(sn
->id_str
);
1908 name_size
= strlen(sn
->name
);
1909 h
.id_str_size
= cpu_to_be16(id_str_size
);
1910 h
.name_size
= cpu_to_be16(name_size
);
1911 offset
= align_offset(offset
, 8);
1912 if (bdrv_pwrite(s
->hd
, offset
, &h
, sizeof(h
)) != sizeof(h
))
1914 offset
+= sizeof(h
);
1915 if (bdrv_pwrite(s
->hd
, offset
, sn
->id_str
, id_str_size
) != id_str_size
)
1917 offset
+= id_str_size
;
1918 if (bdrv_pwrite(s
->hd
, offset
, sn
->name
, name_size
) != name_size
)
1920 offset
+= name_size
;
1923 /* update the various header fields */
1924 data64
= cpu_to_be64(snapshots_offset
);
1925 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, snapshots_offset
),
1926 &data64
, sizeof(data64
)) != sizeof(data64
))
1928 data32
= cpu_to_be32(s
->nb_snapshots
);
1929 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, nb_snapshots
),
1930 &data32
, sizeof(data32
)) != sizeof(data32
))
1933 /* free the old snapshot table */
1934 free_clusters(bs
, s
->snapshots_offset
, s
->snapshots_size
);
1935 s
->snapshots_offset
= snapshots_offset
;
1936 s
->snapshots_size
= snapshots_size
;
1942 static void find_new_snapshot_id(BlockDriverState
*bs
,
1943 char *id_str
, int id_str_size
)
1945 BDRVQcowState
*s
= bs
->opaque
;
1947 int i
, id
, id_max
= 0;
1949 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1950 sn
= s
->snapshots
+ i
;
1951 id
= strtoul(sn
->id_str
, NULL
, 10);
1955 snprintf(id_str
, id_str_size
, "%d", id_max
+ 1);
1958 static int find_snapshot_by_id(BlockDriverState
*bs
, const char *id_str
)
1960 BDRVQcowState
*s
= bs
->opaque
;
1963 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1964 if (!strcmp(s
->snapshots
[i
].id_str
, id_str
))
1970 static int find_snapshot_by_id_or_name(BlockDriverState
*bs
, const char *name
)
1972 BDRVQcowState
*s
= bs
->opaque
;
1975 ret
= find_snapshot_by_id(bs
, name
);
1978 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
1979 if (!strcmp(s
->snapshots
[i
].name
, name
))
1985 /* if no id is provided, a new one is constructed */
1986 static int qcow_snapshot_create(BlockDriverState
*bs
,
1987 QEMUSnapshotInfo
*sn_info
)
1989 BDRVQcowState
*s
= bs
->opaque
;
1990 QCowSnapshot
*snapshots1
, sn1
, *sn
= &sn1
;
1992 uint64_t *l1_table
= NULL
;
1994 memset(sn
, 0, sizeof(*sn
));
1996 if (sn_info
->id_str
[0] == '\0') {
1997 /* compute a new id */
1998 find_new_snapshot_id(bs
, sn_info
->id_str
, sizeof(sn_info
->id_str
));
2001 /* check that the ID is unique */
2002 if (find_snapshot_by_id(bs
, sn_info
->id_str
) >= 0)
2005 sn
->id_str
= qemu_strdup(sn_info
->id_str
);
2008 sn
->name
= qemu_strdup(sn_info
->name
);
2011 sn
->vm_state_size
= sn_info
->vm_state_size
;
2012 sn
->date_sec
= sn_info
->date_sec
;
2013 sn
->date_nsec
= sn_info
->date_nsec
;
2014 sn
->vm_clock_nsec
= sn_info
->vm_clock_nsec
;
2016 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1);
2020 /* create the L1 table of the snapshot */
2021 sn
->l1_table_offset
= alloc_clusters(bs
, s
->l1_size
* sizeof(uint64_t));
2022 sn
->l1_size
= s
->l1_size
;
2024 l1_table
= qemu_malloc(s
->l1_size
* sizeof(uint64_t));
2027 for(i
= 0; i
< s
->l1_size
; i
++) {
2028 l1_table
[i
] = cpu_to_be64(s
->l1_table
[i
]);
2030 if (bdrv_pwrite(s
->hd
, sn
->l1_table_offset
,
2031 l1_table
, s
->l1_size
* sizeof(uint64_t)) !=
2032 (s
->l1_size
* sizeof(uint64_t)))
2034 qemu_free(l1_table
);
2037 snapshots1
= qemu_malloc((s
->nb_snapshots
+ 1) * sizeof(QCowSnapshot
));
2041 memcpy(snapshots1
, s
->snapshots
, s
->nb_snapshots
* sizeof(QCowSnapshot
));
2042 qemu_free(s
->snapshots
);
2044 s
->snapshots
= snapshots1
;
2045 s
->snapshots
[s
->nb_snapshots
++] = *sn
;
2047 if (qcow_write_snapshots(bs
) < 0)
2050 check_refcounts(bs
);
2054 qemu_free(sn
->name
);
2055 qemu_free(l1_table
);
2059 /* copy the snapshot 'snapshot_name' into the current disk image */
2060 static int qcow_snapshot_goto(BlockDriverState
*bs
,
2061 const char *snapshot_id
)
2063 BDRVQcowState
*s
= bs
->opaque
;
2065 int i
, snapshot_index
, l1_size2
;
2067 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2068 if (snapshot_index
< 0)
2070 sn
= &s
->snapshots
[snapshot_index
];
2072 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, -1) < 0)
2075 if (grow_l1_table(bs
, sn
->l1_size
) < 0)
2078 s
->l1_size
= sn
->l1_size
;
2079 l1_size2
= s
->l1_size
* sizeof(uint64_t);
2080 /* copy the snapshot l1 table to the current l1 table */
2081 if (bdrv_pread(s
->hd
, sn
->l1_table_offset
,
2082 s
->l1_table
, l1_size2
) != l1_size2
)
2084 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
,
2085 s
->l1_table
, l1_size2
) != l1_size2
)
2087 for(i
= 0;i
< s
->l1_size
; i
++) {
2088 be64_to_cpus(&s
->l1_table
[i
]);
2091 if (update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 1) < 0)
2095 check_refcounts(bs
);
2102 static int qcow_snapshot_delete(BlockDriverState
*bs
, const char *snapshot_id
)
2104 BDRVQcowState
*s
= bs
->opaque
;
2106 int snapshot_index
, ret
;
2108 snapshot_index
= find_snapshot_by_id_or_name(bs
, snapshot_id
);
2109 if (snapshot_index
< 0)
2111 sn
= &s
->snapshots
[snapshot_index
];
2113 ret
= update_snapshot_refcount(bs
, sn
->l1_table_offset
, sn
->l1_size
, -1);
2116 /* must update the copied flag on the current cluster offsets */
2117 ret
= update_snapshot_refcount(bs
, s
->l1_table_offset
, s
->l1_size
, 0);
2120 free_clusters(bs
, sn
->l1_table_offset
, sn
->l1_size
* sizeof(uint64_t));
2122 qemu_free(sn
->id_str
);
2123 qemu_free(sn
->name
);
2124 memmove(sn
, sn
+ 1, (s
->nb_snapshots
- snapshot_index
- 1) * sizeof(*sn
));
2126 ret
= qcow_write_snapshots(bs
);
2128 /* XXX: restore snapshot if error ? */
2132 check_refcounts(bs
);
2137 static int qcow_snapshot_list(BlockDriverState
*bs
,
2138 QEMUSnapshotInfo
**psn_tab
)
2140 BDRVQcowState
*s
= bs
->opaque
;
2141 QEMUSnapshotInfo
*sn_tab
, *sn_info
;
2145 sn_tab
= qemu_mallocz(s
->nb_snapshots
* sizeof(QEMUSnapshotInfo
));
2148 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2149 sn_info
= sn_tab
+ i
;
2150 sn
= s
->snapshots
+ i
;
2151 pstrcpy(sn_info
->id_str
, sizeof(sn_info
->id_str
),
2153 pstrcpy(sn_info
->name
, sizeof(sn_info
->name
),
2155 sn_info
->vm_state_size
= sn
->vm_state_size
;
2156 sn_info
->date_sec
= sn
->date_sec
;
2157 sn_info
->date_nsec
= sn
->date_nsec
;
2158 sn_info
->vm_clock_nsec
= sn
->vm_clock_nsec
;
2161 return s
->nb_snapshots
;
2168 /*********************************************************/
2169 /* refcount handling */
2171 static int refcount_init(BlockDriverState
*bs
)
2173 BDRVQcowState
*s
= bs
->opaque
;
2174 int ret
, refcount_table_size2
, i
;
2176 s
->refcount_block_cache
= qemu_malloc(s
->cluster_size
);
2177 if (!s
->refcount_block_cache
)
2179 refcount_table_size2
= s
->refcount_table_size
* sizeof(uint64_t);
2180 s
->refcount_table
= qemu_malloc(refcount_table_size2
);
2181 if (!s
->refcount_table
)
2183 if (s
->refcount_table_size
> 0) {
2184 ret
= bdrv_pread(s
->hd
, s
->refcount_table_offset
,
2185 s
->refcount_table
, refcount_table_size2
);
2186 if (ret
!= refcount_table_size2
)
2188 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2189 be64_to_cpus(&s
->refcount_table
[i
]);
2196 static void refcount_close(BlockDriverState
*bs
)
2198 BDRVQcowState
*s
= bs
->opaque
;
2199 qemu_free(s
->refcount_block_cache
);
2200 qemu_free(s
->refcount_table
);
2204 static int load_refcount_block(BlockDriverState
*bs
,
2205 int64_t refcount_block_offset
)
2207 BDRVQcowState
*s
= bs
->opaque
;
2209 ret
= bdrv_pread(s
->hd
, refcount_block_offset
, s
->refcount_block_cache
,
2211 if (ret
!= s
->cluster_size
)
2213 s
->refcount_block_cache_offset
= refcount_block_offset
;
2217 static void scan_refcount(BlockDriverState
*bs
, int64_t *high
)
2219 BDRVQcowState
*s
= bs
->opaque
;
2220 int64_t refcnt_index
, cluster_index
, cluster_end
, h
= 0;
2222 for (refcnt_index
=0; refcnt_index
< s
->refcount_table_size
; refcnt_index
++){
2223 if (s
->refcount_table
[refcnt_index
] == 0) {
2226 cluster_index
= refcnt_index
<< (s
->cluster_bits
- REFCOUNT_SHIFT
);
2227 cluster_end
= (refcnt_index
+ 1) << (s
->cluster_bits
- REFCOUNT_SHIFT
);
2228 for ( ; cluster_index
< cluster_end
; cluster_index
++) {
2229 if (get_refcount(bs
, cluster_index
) == 0)
2230 /* do nothing -- reserved for free counting */;
2240 static int get_refcount(BlockDriverState
*bs
, int64_t cluster_index
)
2242 BDRVQcowState
*s
= bs
->opaque
;
2243 int refcount_table_index
, block_index
;
2244 int64_t refcount_block_offset
;
2246 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2247 if (refcount_table_index
>= s
->refcount_table_size
)
2249 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2250 if (!refcount_block_offset
)
2252 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2253 /* better than nothing: return allocated if read error */
2254 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2257 block_index
= cluster_index
&
2258 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2259 return be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2262 /* return < 0 if error */
2263 static int64_t alloc_clusters_noref(BlockDriverState
*bs
, int64_t size
)
2265 BDRVQcowState
*s
= bs
->opaque
;
2268 nb_clusters
= size_to_clusters(s
, size
);
2270 for(i
= 0; i
< nb_clusters
; i
++) {
2271 int64_t i
= s
->free_cluster_index
++;
2272 if (get_refcount(bs
, i
) != 0)
2276 printf("alloc_clusters: size=%lld -> %lld\n",
2278 (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
);
2281 if (s
->highest_alloc
< s
->free_cluster_index
)
2282 s
->highest_alloc
= s
->free_cluster_index
;
2284 return (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
;
2287 static int64_t alloc_clusters(BlockDriverState
*bs
, int64_t size
)
2291 offset
= alloc_clusters_noref(bs
, size
);
2292 update_refcount(bs
, offset
, size
, 1);
2296 /* only used to allocate compressed sectors. We try to allocate
2297 contiguous sectors. size must be <= cluster_size */
2298 static int64_t alloc_bytes(BlockDriverState
*bs
, int size
)
2300 BDRVQcowState
*s
= bs
->opaque
;
2301 int64_t offset
, cluster_offset
;
2302 int free_in_cluster
;
2304 assert(size
> 0 && size
<= s
->cluster_size
);
2305 if (s
->free_byte_offset
== 0) {
2306 s
->free_byte_offset
= alloc_clusters(bs
, s
->cluster_size
);
2309 free_in_cluster
= s
->cluster_size
-
2310 (s
->free_byte_offset
& (s
->cluster_size
- 1));
2311 if (size
<= free_in_cluster
) {
2312 /* enough space in current cluster */
2313 offset
= s
->free_byte_offset
;
2314 s
->free_byte_offset
+= size
;
2315 free_in_cluster
-= size
;
2316 if (free_in_cluster
== 0)
2317 s
->free_byte_offset
= 0;
2318 if ((offset
& (s
->cluster_size
- 1)) != 0)
2319 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2321 offset
= alloc_clusters(bs
, s
->cluster_size
);
2322 cluster_offset
= s
->free_byte_offset
& ~(s
->cluster_size
- 1);
2323 if ((cluster_offset
+ s
->cluster_size
) == offset
) {
2324 /* we are lucky: contiguous data */
2325 offset
= s
->free_byte_offset
;
2326 update_cluster_refcount(bs
, offset
>> s
->cluster_bits
, 1);
2327 s
->free_byte_offset
+= size
;
2329 s
->free_byte_offset
= offset
;
2336 static void free_clusters(BlockDriverState
*bs
,
2337 int64_t offset
, int64_t size
)
2339 update_refcount(bs
, offset
, size
, -1);
2342 static int grow_refcount_table(BlockDriverState
*bs
, int min_size
)
2344 BDRVQcowState
*s
= bs
->opaque
;
2345 int new_table_size
, new_table_size2
, refcount_table_clusters
, i
, ret
;
2346 uint64_t *new_table
;
2347 int64_t table_offset
;
2350 int64_t old_table_offset
;
2352 if (min_size
<= s
->refcount_table_size
)
2354 /* compute new table size */
2355 refcount_table_clusters
= s
->refcount_table_size
>> (s
->cluster_bits
- 3);
2357 if (refcount_table_clusters
== 0) {
2358 refcount_table_clusters
= 1;
2360 refcount_table_clusters
= (refcount_table_clusters
* 3 + 1) / 2;
2362 new_table_size
= refcount_table_clusters
<< (s
->cluster_bits
- 3);
2363 if (min_size
<= new_table_size
)
2367 printf("grow_refcount_table from %d to %d\n",
2368 s
->refcount_table_size
,
2371 new_table_size2
= new_table_size
* sizeof(uint64_t);
2372 new_table
= qemu_mallocz(new_table_size2
);
2375 memcpy(new_table
, s
->refcount_table
,
2376 s
->refcount_table_size
* sizeof(uint64_t));
2377 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2378 cpu_to_be64s(&new_table
[i
]);
2379 /* Note: we cannot update the refcount now to avoid recursion */
2380 table_offset
= alloc_clusters_noref(bs
, new_table_size2
);
2381 ret
= bdrv_pwrite(s
->hd
, table_offset
, new_table
, new_table_size2
);
2382 if (ret
!= new_table_size2
)
2384 for(i
= 0; i
< s
->refcount_table_size
; i
++)
2385 be64_to_cpus(&new_table
[i
]);
2387 cpu_to_be64w((uint64_t*)data
, table_offset
);
2388 cpu_to_be32w((uint32_t*)(data
+ 8), refcount_table_clusters
);
2389 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, refcount_table_offset
),
2390 data
, sizeof(data
)) != sizeof(data
))
2392 qemu_free(s
->refcount_table
);
2393 old_table_offset
= s
->refcount_table_offset
;
2394 old_table_size
= s
->refcount_table_size
;
2395 s
->refcount_table
= new_table
;
2396 s
->refcount_table_size
= new_table_size
;
2397 s
->refcount_table_offset
= table_offset
;
2399 update_refcount(bs
, table_offset
, new_table_size2
, 1);
2400 free_clusters(bs
, old_table_offset
, old_table_size
* sizeof(uint64_t));
2403 free_clusters(bs
, table_offset
, new_table_size2
);
2404 qemu_free(new_table
);
2408 /* addend must be 1 or -1 */
2409 /* XXX: cache several refcount block clusters ? */
2410 static int update_cluster_refcount(BlockDriverState
*bs
,
2411 int64_t cluster_index
,
2414 BDRVQcowState
*s
= bs
->opaque
;
2415 int64_t offset
, refcount_block_offset
;
2416 int ret
, refcount_table_index
, block_index
, refcount
;
2419 refcount_table_index
= cluster_index
>> (s
->cluster_bits
- REFCOUNT_SHIFT
);
2420 if (refcount_table_index
>= s
->refcount_table_size
) {
2423 ret
= grow_refcount_table(bs
, refcount_table_index
+ 1);
2427 refcount_block_offset
= s
->refcount_table
[refcount_table_index
];
2428 if (!refcount_block_offset
) {
2431 /* create a new refcount block */
2432 /* Note: we cannot update the refcount now to avoid recursion */
2433 offset
= alloc_clusters_noref(bs
, s
->cluster_size
);
2434 memset(s
->refcount_block_cache
, 0, s
->cluster_size
);
2435 ret
= bdrv_pwrite(s
->hd
, offset
, s
->refcount_block_cache
, s
->cluster_size
);
2436 if (ret
!= s
->cluster_size
)
2438 s
->refcount_table
[refcount_table_index
] = offset
;
2439 data64
= cpu_to_be64(offset
);
2440 ret
= bdrv_pwrite(s
->hd
, s
->refcount_table_offset
+
2441 refcount_table_index
* sizeof(uint64_t),
2442 &data64
, sizeof(data64
));
2443 if (ret
!= sizeof(data64
))
2446 refcount_block_offset
= offset
;
2447 s
->refcount_block_cache_offset
= offset
;
2448 update_refcount(bs
, offset
, s
->cluster_size
, 1);
2450 if (refcount_block_offset
!= s
->refcount_block_cache_offset
) {
2451 if (load_refcount_block(bs
, refcount_block_offset
) < 0)
2455 /* we can update the count and save it */
2456 block_index
= cluster_index
&
2457 ((1 << (s
->cluster_bits
- REFCOUNT_SHIFT
)) - 1);
2458 refcount
= be16_to_cpu(s
->refcount_block_cache
[block_index
]);
2460 if (refcount
< 0 || refcount
> 0xffff)
2462 if (refcount
== 0 && cluster_index
< s
->free_cluster_index
) {
2463 s
->free_cluster_index
= cluster_index
;
2465 s
->refcount_block_cache
[block_index
] = cpu_to_be16(refcount
);
2466 if (bdrv_pwrite(s
->hd
,
2467 refcount_block_offset
+ (block_index
<< REFCOUNT_SHIFT
),
2468 &s
->refcount_block_cache
[block_index
], 2) != 2)
2473 static void update_refcount(BlockDriverState
*bs
,
2474 int64_t offset
, int64_t length
,
2477 BDRVQcowState
*s
= bs
->opaque
;
2478 int64_t start
, last
, cluster_offset
;
2481 printf("update_refcount: offset=%lld size=%lld addend=%d\n",
2482 offset
, length
, addend
);
2486 start
= offset
& ~(s
->cluster_size
- 1);
2487 last
= (offset
+ length
- 1) & ~(s
->cluster_size
- 1);
2488 for(cluster_offset
= start
; cluster_offset
<= last
;
2489 cluster_offset
+= s
->cluster_size
) {
2490 update_cluster_refcount(bs
, cluster_offset
>> s
->cluster_bits
, addend
);
2495 static void inc_refcounts(BlockDriverState
*bs
,
2496 uint16_t *refcount_table
,
2497 int refcount_table_size
,
2498 int64_t offset
, int64_t size
)
2500 BDRVQcowState
*s
= bs
->opaque
;
2501 int64_t start
, last
, cluster_offset
;
2507 start
= offset
& ~(s
->cluster_size
- 1);
2508 last
= (offset
+ size
- 1) & ~(s
->cluster_size
- 1);
2509 for(cluster_offset
= start
; cluster_offset
<= last
;
2510 cluster_offset
+= s
->cluster_size
) {
2511 k
= cluster_offset
>> s
->cluster_bits
;
2512 if (k
< 0 || k
>= refcount_table_size
) {
2513 printf("ERROR: invalid cluster offset=0x%llx\n", cluster_offset
);
2515 if (++refcount_table
[k
] == 0) {
2516 printf("ERROR: overflow cluster offset=0x%llx\n", cluster_offset
);
2522 static int check_refcounts_l1(BlockDriverState
*bs
,
2523 uint16_t *refcount_table
,
2524 int refcount_table_size
,
2525 int64_t l1_table_offset
, int l1_size
,
2528 BDRVQcowState
*s
= bs
->opaque
;
2529 uint64_t *l1_table
, *l2_table
, l2_offset
, offset
, l1_size2
;
2530 int l2_size
, i
, j
, nb_csectors
, refcount
;
2533 l1_size2
= l1_size
* sizeof(uint64_t);
2535 inc_refcounts(bs
, refcount_table
, refcount_table_size
,
2536 l1_table_offset
, l1_size2
);
2538 l1_table
= qemu_malloc(l1_size2
);
2541 if (bdrv_pread(s
->hd
, l1_table_offset
,
2542 l1_table
, l1_size2
) != l1_size2
)
2544 for(i
= 0;i
< l1_size
; i
++)
2545 be64_to_cpus(&l1_table
[i
]);
2547 l2_size
= s
->l2_size
* sizeof(uint64_t);
2548 l2_table
= qemu_malloc(l2_size
);
2551 for(i
= 0; i
< l1_size
; i
++) {
2552 l2_offset
= l1_table
[i
];
2555 refcount
= get_refcount(bs
, (l2_offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2556 if ((refcount
== 1) != ((l2_offset
& QCOW_OFLAG_COPIED
) != 0)) {
2557 printf("ERROR OFLAG_COPIED: l2_offset=%llx refcount=%d\n",
2558 l2_offset
, refcount
);
2561 l2_offset
&= ~QCOW_OFLAG_COPIED
;
2562 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, l2_size
) != l2_size
)
2564 for(j
= 0; j
< s
->l2_size
; j
++) {
2565 offset
= be64_to_cpu(l2_table
[j
]);
2567 if (offset
& QCOW_OFLAG_COMPRESSED
) {
2568 if (offset
& QCOW_OFLAG_COPIED
) {
2569 printf("ERROR: cluster %lld: copied flag must never be set for compressed clusters\n",
2570 offset
>> s
->cluster_bits
);
2571 offset
&= ~QCOW_OFLAG_COPIED
;
2573 nb_csectors
= ((offset
>> s
->csize_shift
) &
2575 offset
&= s
->cluster_offset_mask
;
2576 inc_refcounts(bs
, refcount_table
,
2577 refcount_table_size
,
2578 offset
& ~511, nb_csectors
* 512);
2581 refcount
= get_refcount(bs
, (offset
& ~QCOW_OFLAG_COPIED
) >> s
->cluster_bits
);
2582 if ((refcount
== 1) != ((offset
& QCOW_OFLAG_COPIED
) != 0)) {
2583 printf("ERROR OFLAG_COPIED: offset=%llx refcount=%d\n",
2587 offset
&= ~QCOW_OFLAG_COPIED
;
2588 inc_refcounts(bs
, refcount_table
,
2589 refcount_table_size
,
2590 offset
, s
->cluster_size
);
2594 inc_refcounts(bs
, refcount_table
,
2595 refcount_table_size
,
2600 qemu_free(l1_table
);
2601 qemu_free(l2_table
);
2604 printf("ERROR: I/O error in check_refcounts_l1\n");
2605 qemu_free(l1_table
);
2606 qemu_free(l2_table
);
2610 static void check_refcounts(BlockDriverState
*bs
)
2612 BDRVQcowState
*s
= bs
->opaque
;
2614 int nb_clusters
, refcount1
, refcount2
, i
;
2616 uint16_t *refcount_table
;
2618 size
= bdrv_getlength(s
->hd
);
2619 nb_clusters
= size_to_clusters(s
, size
);
2620 refcount_table
= qemu_mallocz(nb_clusters
* sizeof(uint16_t));
2623 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2624 0, s
->cluster_size
);
2626 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2627 s
->l1_table_offset
, s
->l1_size
, 1);
2630 for(i
= 0; i
< s
->nb_snapshots
; i
++) {
2631 sn
= s
->snapshots
+ i
;
2632 check_refcounts_l1(bs
, refcount_table
, nb_clusters
,
2633 sn
->l1_table_offset
, sn
->l1_size
, 0);
2635 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2636 s
->snapshots_offset
, s
->snapshots_size
);
2639 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2640 s
->refcount_table_offset
,
2641 s
->refcount_table_size
* sizeof(uint64_t));
2642 for(i
= 0; i
< s
->refcount_table_size
; i
++) {
2644 offset
= s
->refcount_table
[i
];
2646 inc_refcounts(bs
, refcount_table
, nb_clusters
,
2647 offset
, s
->cluster_size
);
2651 /* compare ref counts */
2652 for(i
= 0; i
< nb_clusters
; i
++) {
2653 refcount1
= get_refcount(bs
, i
);
2654 refcount2
= refcount_table
[i
];
2655 if (refcount1
!= refcount2
)
2656 printf("ERROR cluster %d refcount=%d reference=%d\n",
2657 i
, refcount1
, refcount2
);
2660 qemu_free(refcount_table
);
2664 static void dump_refcounts(BlockDriverState
*bs
)
2666 BDRVQcowState
*s
= bs
->opaque
;
2667 int64_t nb_clusters
, k
, k1
, size
;
2670 size
= bdrv_getlength(s
->hd
);
2671 nb_clusters
= size_to_clusters(s
, size
);
2672 for(k
= 0; k
< nb_clusters
;) {
2674 refcount
= get_refcount(bs
, k
);
2676 while (k
< nb_clusters
&& get_refcount(bs
, k
) == refcount
)
2678 printf("%lld: refcount=%d nb=%lld\n", k
, refcount
, k
- k1
);
2684 BlockDriver bdrv_qcow2
= {
2686 sizeof(BDRVQcowState
),
2698 .bdrv_aio_read
= qcow_aio_read
,
2699 .bdrv_aio_write
= qcow_aio_write
,
2700 .bdrv_aio_cancel
= qcow_aio_cancel
,
2701 .aiocb_size
= sizeof(QCowAIOCB
),
2702 .bdrv_write_compressed
= qcow_write_compressed
,
2704 .bdrv_snapshot_create
= qcow_snapshot_create
,
2705 .bdrv_snapshot_goto
= qcow_snapshot_goto
,
2706 .bdrv_snapshot_delete
= qcow_snapshot_delete
,
2707 .bdrv_snapshot_list
= qcow_snapshot_list
,
2708 .bdrv_get_info
= qcow_get_info
,