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
27 #include "qemu-common.h"
28 #include "block_int.h"
29 #include "block/qcow2.h"
31 int qcow2_grow_l1_table(BlockDriverState
*bs
, int min_size
)
33 BDRVQcowState
*s
= bs
->opaque
;
34 int new_l1_size
, new_l1_size2
, ret
, i
;
35 uint64_t *new_l1_table
;
36 uint64_t new_l1_table_offset
;
39 new_l1_size
= s
->l1_size
;
40 if (min_size
<= new_l1_size
)
42 if (new_l1_size
== 0) {
45 while (min_size
> new_l1_size
) {
46 new_l1_size
= (new_l1_size
* 3 + 1) / 2;
49 printf("grow l1_table from %d to %d\n", s
->l1_size
, new_l1_size
);
52 new_l1_size2
= sizeof(uint64_t) * new_l1_size
;
53 new_l1_table
= qemu_mallocz(align_offset(new_l1_size2
, 512));
54 memcpy(new_l1_table
, s
->l1_table
, s
->l1_size
* sizeof(uint64_t));
56 /* write new table (align to cluster) */
57 new_l1_table_offset
= qcow2_alloc_clusters(bs
, new_l1_size2
);
59 for(i
= 0; i
< s
->l1_size
; i
++)
60 new_l1_table
[i
] = cpu_to_be64(new_l1_table
[i
]);
61 ret
= bdrv_pwrite(s
->hd
, new_l1_table_offset
, new_l1_table
, new_l1_size2
);
62 if (ret
!= new_l1_size2
)
64 for(i
= 0; i
< s
->l1_size
; i
++)
65 new_l1_table
[i
] = be64_to_cpu(new_l1_table
[i
]);
68 cpu_to_be32w((uint32_t*)data
, new_l1_size
);
69 cpu_to_be64w((uint64_t*)(data
+ 4), new_l1_table_offset
);
70 if (bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_size
), data
,
71 sizeof(data
)) != sizeof(data
))
73 qemu_free(s
->l1_table
);
74 qcow2_free_clusters(bs
, s
->l1_table_offset
, s
->l1_size
* sizeof(uint64_t));
75 s
->l1_table_offset
= new_l1_table_offset
;
76 s
->l1_table
= new_l1_table
;
77 s
->l1_size
= new_l1_size
;
80 qemu_free(s
->l1_table
);
84 void qcow2_l2_cache_reset(BlockDriverState
*bs
)
86 BDRVQcowState
*s
= bs
->opaque
;
88 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
89 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
90 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
93 static inline int l2_cache_new_entry(BlockDriverState
*bs
)
95 BDRVQcowState
*s
= bs
->opaque
;
99 /* find a new entry in the least used one */
101 min_count
= 0xffffffff;
102 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
103 if (s
->l2_cache_counts
[i
] < min_count
) {
104 min_count
= s
->l2_cache_counts
[i
];
114 * seek l2_offset in the l2_cache table
115 * if not found, return NULL,
117 * increments the l2 cache hit count of the entry,
118 * if counter overflow, divide by two all counters
119 * return the pointer to the l2 cache entry
123 static uint64_t *seek_l2_table(BDRVQcowState
*s
, uint64_t l2_offset
)
127 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
128 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
129 /* increment the hit count */
130 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
131 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
132 s
->l2_cache_counts
[j
] >>= 1;
135 return s
->l2_cache
+ (i
<< s
->l2_bits
);
144 * Loads a L2 table into memory. If the table is in the cache, the cache
145 * is used; otherwise the L2 table is loaded from the image file.
147 * Returns a pointer to the L2 table on success, or NULL if the read from
148 * the image file failed.
151 static uint64_t *l2_load(BlockDriverState
*bs
, uint64_t l2_offset
)
153 BDRVQcowState
*s
= bs
->opaque
;
157 /* seek if the table for the given offset is in the cache */
159 l2_table
= seek_l2_table(s
, l2_offset
);
160 if (l2_table
!= NULL
)
163 /* not found: load a new entry in the least used one */
165 min_index
= l2_cache_new_entry(bs
);
166 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
167 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
168 s
->l2_size
* sizeof(uint64_t))
170 s
->l2_cache_offsets
[min_index
] = l2_offset
;
171 s
->l2_cache_counts
[min_index
] = 1;
177 * Writes one sector of the L1 table to the disk (can't update single entries
178 * and we really don't want bdrv_pread to perform a read-modify-write)
180 #define L1_ENTRIES_PER_SECTOR (512 / 8)
181 static int write_l1_entry(BDRVQcowState
*s
, int l1_index
)
183 uint64_t buf
[L1_ENTRIES_PER_SECTOR
];
187 l1_start_index
= l1_index
& ~(L1_ENTRIES_PER_SECTOR
- 1);
188 for (i
= 0; i
< L1_ENTRIES_PER_SECTOR
; i
++) {
189 buf
[i
] = cpu_to_be64(s
->l1_table
[l1_start_index
+ i
]);
192 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
+ 8 * l1_start_index
,
193 buf
, sizeof(buf
)) != sizeof(buf
))
204 * Allocate a new l2 entry in the file. If l1_index points to an already
205 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
206 * table) copy the contents of the old L2 table into the newly allocated one.
207 * Otherwise the new table is initialized with zeros.
211 static uint64_t *l2_allocate(BlockDriverState
*bs
, int l1_index
)
213 BDRVQcowState
*s
= bs
->opaque
;
215 uint64_t old_l2_offset
;
216 uint64_t *l2_table
, l2_offset
;
218 old_l2_offset
= s
->l1_table
[l1_index
];
220 /* allocate a new l2 entry */
222 l2_offset
= qcow2_alloc_clusters(bs
, s
->l2_size
* sizeof(uint64_t));
224 /* update the L1 entry */
226 s
->l1_table
[l1_index
] = l2_offset
| QCOW_OFLAG_COPIED
;
227 if (write_l1_entry(s
, l1_index
) < 0) {
231 /* allocate a new entry in the l2 cache */
233 min_index
= l2_cache_new_entry(bs
);
234 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
236 if (old_l2_offset
== 0) {
237 /* if there was no old l2 table, clear the new table */
238 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
240 /* if there was an old l2 table, read it from the disk */
241 if (bdrv_pread(s
->hd
, old_l2_offset
,
242 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
243 s
->l2_size
* sizeof(uint64_t))
246 /* write the l2 table to the file */
247 if (bdrv_pwrite(s
->hd
, l2_offset
,
248 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
249 s
->l2_size
* sizeof(uint64_t))
252 /* update the l2 cache entry */
254 s
->l2_cache_offsets
[min_index
] = l2_offset
;
255 s
->l2_cache_counts
[min_index
] = 1;
260 static int count_contiguous_clusters(uint64_t nb_clusters
, int cluster_size
,
261 uint64_t *l2_table
, uint64_t start
, uint64_t mask
)
264 uint64_t offset
= be64_to_cpu(l2_table
[0]) & ~mask
;
269 for (i
= start
; i
< start
+ nb_clusters
; i
++)
270 if (offset
+ (uint64_t) i
* cluster_size
!= (be64_to_cpu(l2_table
[i
]) & ~mask
))
276 static int count_contiguous_free_clusters(uint64_t nb_clusters
, uint64_t *l2_table
)
280 while(nb_clusters
-- && l2_table
[i
] == 0)
286 /* The crypt function is compatible with the linux cryptoloop
287 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
289 void qcow2_encrypt_sectors(BDRVQcowState
*s
, int64_t sector_num
,
290 uint8_t *out_buf
, const uint8_t *in_buf
,
291 int nb_sectors
, int enc
,
300 for(i
= 0; i
< nb_sectors
; i
++) {
301 ivec
.ll
[0] = cpu_to_le64(sector_num
);
303 AES_cbc_encrypt(in_buf
, out_buf
, 512, key
,
312 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
313 uint8_t *buf
, int nb_sectors
)
315 BDRVQcowState
*s
= bs
->opaque
;
316 int ret
, index_in_cluster
, n
, n1
;
317 uint64_t cluster_offset
;
319 while (nb_sectors
> 0) {
321 cluster_offset
= qcow2_get_cluster_offset(bs
, sector_num
<< 9, &n
);
322 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
323 if (!cluster_offset
) {
324 if (bs
->backing_hd
) {
325 /* read from the base image */
326 n1
= qcow2_backing_read1(bs
->backing_hd
, sector_num
, buf
, n
);
328 ret
= bdrv_read(bs
->backing_hd
, sector_num
, buf
, n1
);
333 memset(buf
, 0, 512 * n
);
335 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
336 if (qcow2_decompress_cluster(s
, cluster_offset
) < 0)
338 memcpy(buf
, s
->cluster_cache
+ index_in_cluster
* 512, 512 * n
);
340 ret
= bdrv_pread(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
343 if (s
->crypt_method
) {
344 qcow2_encrypt_sectors(s
, sector_num
, buf
, buf
, n
, 0,
345 &s
->aes_decrypt_key
);
355 static int copy_sectors(BlockDriverState
*bs
, uint64_t start_sect
,
356 uint64_t cluster_offset
, int n_start
, int n_end
)
358 BDRVQcowState
*s
= bs
->opaque
;
364 ret
= qcow_read(bs
, start_sect
+ n_start
, s
->cluster_data
, n
);
367 if (s
->crypt_method
) {
368 qcow2_encrypt_sectors(s
, start_sect
+ n_start
,
370 s
->cluster_data
, n
, 1,
371 &s
->aes_encrypt_key
);
373 ret
= bdrv_write(s
->hd
, (cluster_offset
>> 9) + n_start
,
384 * For a given offset of the disk image, return cluster offset in
387 * on entry, *num is the number of contiguous clusters we'd like to
388 * access following offset.
390 * on exit, *num is the number of contiguous clusters we can read.
392 * Return 1, if the offset is found
393 * Return 0, otherwise.
397 uint64_t qcow2_get_cluster_offset(BlockDriverState
*bs
, uint64_t offset
,
400 BDRVQcowState
*s
= bs
->opaque
;
401 unsigned int l1_index
, l2_index
;
402 uint64_t l2_offset
, *l2_table
, cluster_offset
;
404 unsigned int index_in_cluster
, nb_clusters
;
405 uint64_t nb_available
, nb_needed
;
407 index_in_cluster
= (offset
>> 9) & (s
->cluster_sectors
- 1);
408 nb_needed
= *num
+ index_in_cluster
;
410 l1_bits
= s
->l2_bits
+ s
->cluster_bits
;
412 /* compute how many bytes there are between the offset and
413 * the end of the l1 entry
416 nb_available
= (1ULL << l1_bits
) - (offset
& ((1ULL << l1_bits
) - 1));
418 /* compute the number of available sectors */
420 nb_available
= (nb_available
>> 9) + index_in_cluster
;
422 if (nb_needed
> nb_available
) {
423 nb_needed
= nb_available
;
428 /* seek the the l2 offset in the l1 table */
430 l1_index
= offset
>> l1_bits
;
431 if (l1_index
>= s
->l1_size
)
434 l2_offset
= s
->l1_table
[l1_index
];
436 /* seek the l2 table of the given l2 offset */
441 /* load the l2 table in memory */
443 l2_offset
&= ~QCOW_OFLAG_COPIED
;
444 l2_table
= l2_load(bs
, l2_offset
);
445 if (l2_table
== NULL
)
448 /* find the cluster offset for the given disk offset */
450 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
451 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
452 nb_clusters
= size_to_clusters(s
, nb_needed
<< 9);
454 if (!cluster_offset
) {
455 /* how many empty clusters ? */
456 c
= count_contiguous_free_clusters(nb_clusters
, &l2_table
[l2_index
]);
458 /* how many allocated clusters ? */
459 c
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
460 &l2_table
[l2_index
], 0, QCOW_OFLAG_COPIED
);
463 nb_available
= (c
* s
->cluster_sectors
);
465 if (nb_available
> nb_needed
)
466 nb_available
= nb_needed
;
468 *num
= nb_available
- index_in_cluster
;
470 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
476 * for a given disk offset, load (and allocate if needed)
479 * the l2 table offset in the qcow2 file and the cluster index
480 * in the l2 table are given to the caller.
484 static int get_cluster_table(BlockDriverState
*bs
, uint64_t offset
,
485 uint64_t **new_l2_table
,
486 uint64_t *new_l2_offset
,
489 BDRVQcowState
*s
= bs
->opaque
;
490 unsigned int l1_index
, l2_index
;
491 uint64_t l2_offset
, *l2_table
;
494 /* seek the the l2 offset in the l1 table */
496 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
497 if (l1_index
>= s
->l1_size
) {
498 ret
= qcow2_grow_l1_table(bs
, l1_index
+ 1);
502 l2_offset
= s
->l1_table
[l1_index
];
504 /* seek the l2 table of the given l2 offset */
506 if (l2_offset
& QCOW_OFLAG_COPIED
) {
507 /* load the l2 table in memory */
508 l2_offset
&= ~QCOW_OFLAG_COPIED
;
509 l2_table
= l2_load(bs
, l2_offset
);
510 if (l2_table
== NULL
)
514 qcow2_free_clusters(bs
, l2_offset
, s
->l2_size
* sizeof(uint64_t));
515 l2_table
= l2_allocate(bs
, l1_index
);
516 if (l2_table
== NULL
)
518 l2_offset
= s
->l1_table
[l1_index
] & ~QCOW_OFLAG_COPIED
;
521 /* find the cluster offset for the given disk offset */
523 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
525 *new_l2_table
= l2_table
;
526 *new_l2_offset
= l2_offset
;
527 *new_l2_index
= l2_index
;
533 * alloc_compressed_cluster_offset
535 * For a given offset of the disk image, return cluster offset in
538 * If the offset is not found, allocate a new compressed cluster.
540 * Return the cluster offset if successful,
541 * Return 0, otherwise.
545 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState
*bs
,
549 BDRVQcowState
*s
= bs
->opaque
;
551 uint64_t l2_offset
, *l2_table
, cluster_offset
;
554 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
558 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
559 if (cluster_offset
& QCOW_OFLAG_COPIED
)
560 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
563 qcow2_free_any_clusters(bs
, cluster_offset
, 1);
565 cluster_offset
= qcow2_alloc_bytes(bs
, compressed_size
);
566 nb_csectors
= ((cluster_offset
+ compressed_size
- 1) >> 9) -
567 (cluster_offset
>> 9);
569 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
570 ((uint64_t)nb_csectors
<< s
->csize_shift
);
572 /* update L2 table */
574 /* compressed clusters never have the copied flag */
576 l2_table
[l2_index
] = cpu_to_be64(cluster_offset
);
577 if (bdrv_pwrite(s
->hd
,
578 l2_offset
+ l2_index
* sizeof(uint64_t),
580 sizeof(uint64_t)) != sizeof(uint64_t))
583 return cluster_offset
;
587 * Write L2 table updates to disk, writing whole sectors to avoid a
588 * read-modify-write in bdrv_pwrite
590 #define L2_ENTRIES_PER_SECTOR (512 / 8)
591 static int write_l2_entries(BDRVQcowState
*s
, uint64_t *l2_table
,
592 uint64_t l2_offset
, int l2_index
, int num
)
594 int l2_start_index
= l2_index
& ~(L1_ENTRIES_PER_SECTOR
- 1);
595 int start_offset
= (8 * l2_index
) & ~511;
596 int end_offset
= (8 * (l2_index
+ num
) + 511) & ~511;
597 size_t len
= end_offset
- start_offset
;
599 if (bdrv_pwrite(s
->hd
, l2_offset
+ start_offset
, &l2_table
[l2_start_index
],
608 int qcow2_alloc_cluster_link_l2(BlockDriverState
*bs
, uint64_t cluster_offset
,
611 BDRVQcowState
*s
= bs
->opaque
;
612 int i
, j
= 0, l2_index
, ret
;
613 uint64_t *old_cluster
, start_sect
, l2_offset
, *l2_table
;
615 if (m
->nb_clusters
== 0)
618 old_cluster
= qemu_malloc(m
->nb_clusters
* sizeof(uint64_t));
620 /* copy content of unmodified sectors */
621 start_sect
= (m
->offset
& ~(s
->cluster_size
- 1)) >> 9;
623 ret
= copy_sectors(bs
, start_sect
, cluster_offset
, 0, m
->n_start
);
628 if (m
->nb_available
& (s
->cluster_sectors
- 1)) {
629 uint64_t end
= m
->nb_available
& ~(uint64_t)(s
->cluster_sectors
- 1);
630 ret
= copy_sectors(bs
, start_sect
+ end
, cluster_offset
+ (end
<< 9),
631 m
->nb_available
- end
, s
->cluster_sectors
);
637 /* update L2 table */
638 if (!get_cluster_table(bs
, m
->offset
, &l2_table
, &l2_offset
, &l2_index
))
641 for (i
= 0; i
< m
->nb_clusters
; i
++) {
642 /* if two concurrent writes happen to the same unallocated cluster
643 * each write allocates separate cluster and writes data concurrently.
644 * The first one to complete updates l2 table with pointer to its
645 * cluster the second one has to do RMW (which is done above by
646 * copy_sectors()), update l2 table with its cluster pointer and free
647 * old cluster. This is what this loop does */
648 if(l2_table
[l2_index
+ i
] != 0)
649 old_cluster
[j
++] = l2_table
[l2_index
+ i
];
651 l2_table
[l2_index
+ i
] = cpu_to_be64((cluster_offset
+
652 (i
<< s
->cluster_bits
)) | QCOW_OFLAG_COPIED
);
655 if (write_l2_entries(s
, l2_table
, l2_offset
, l2_index
, m
->nb_clusters
) < 0) {
660 for (i
= 0; i
< j
; i
++)
661 qcow2_free_any_clusters(bs
,
662 be64_to_cpu(old_cluster
[i
]) & ~QCOW_OFLAG_COPIED
, 1);
666 qemu_free(old_cluster
);
671 * alloc_cluster_offset
673 * For a given offset of the disk image, return cluster offset in
676 * If the offset is not found, allocate a new cluster.
678 * Return the cluster offset if successful,
679 * Return 0, otherwise.
683 uint64_t qcow2_alloc_cluster_offset(BlockDriverState
*bs
,
685 int n_start
, int n_end
,
686 int *num
, QCowL2Meta
*m
)
688 BDRVQcowState
*s
= bs
->opaque
;
690 uint64_t l2_offset
, *l2_table
, cluster_offset
;
691 unsigned int nb_clusters
, i
= 0;
692 QCowL2Meta
*old_alloc
;
694 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
698 nb_clusters
= size_to_clusters(s
, n_end
<< 9);
700 nb_clusters
= MIN(nb_clusters
, s
->l2_size
- l2_index
);
702 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
704 /* We keep all QCOW_OFLAG_COPIED clusters */
706 if (cluster_offset
& QCOW_OFLAG_COPIED
) {
707 nb_clusters
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
708 &l2_table
[l2_index
], 0, 0);
710 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
716 /* for the moment, multiple compressed clusters are not managed */
718 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
)
721 /* how many available clusters ? */
723 while (i
< nb_clusters
) {
724 i
+= count_contiguous_clusters(nb_clusters
- i
, s
->cluster_size
,
725 &l2_table
[l2_index
], i
, 0);
727 if(be64_to_cpu(l2_table
[l2_index
+ i
]))
730 i
+= count_contiguous_free_clusters(nb_clusters
- i
,
731 &l2_table
[l2_index
+ i
]);
733 cluster_offset
= be64_to_cpu(l2_table
[l2_index
+ i
]);
735 if ((cluster_offset
& QCOW_OFLAG_COPIED
) ||
736 (cluster_offset
& QCOW_OFLAG_COMPRESSED
))
742 * Check if there already is an AIO write request in flight which allocates
743 * the same cluster. In this case we need to wait until the previous
744 * request has completed and updated the L2 table accordingly.
746 QLIST_FOREACH(old_alloc
, &s
->cluster_allocs
, next_in_flight
) {
748 uint64_t end_offset
= offset
+ nb_clusters
* s
->cluster_size
;
749 uint64_t old_offset
= old_alloc
->offset
;
750 uint64_t old_end_offset
= old_alloc
->offset
+
751 old_alloc
->nb_clusters
* s
->cluster_size
;
753 if (end_offset
< old_offset
|| offset
> old_end_offset
) {
754 /* No intersection */
756 if (offset
< old_offset
) {
757 /* Stop at the start of a running allocation */
758 nb_clusters
= (old_offset
- offset
) >> s
->cluster_bits
;
763 if (nb_clusters
== 0) {
764 /* Set dependency and wait for a callback */
765 m
->depends_on
= old_alloc
;
777 QLIST_INSERT_HEAD(&s
->cluster_allocs
, m
, next_in_flight
);
779 /* allocate a new cluster */
781 cluster_offset
= qcow2_alloc_clusters(bs
, nb_clusters
* s
->cluster_size
);
783 /* save info needed for meta data update */
785 m
->n_start
= n_start
;
786 m
->nb_clusters
= nb_clusters
;
789 m
->nb_available
= MIN(nb_clusters
<< (s
->cluster_bits
- 9), n_end
);
791 *num
= m
->nb_available
- n_start
;
793 return cluster_offset
;
796 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
797 const uint8_t *buf
, int buf_size
)
799 z_stream strm1
, *strm
= &strm1
;
802 memset(strm
, 0, sizeof(*strm
));
804 strm
->next_in
= (uint8_t *)buf
;
805 strm
->avail_in
= buf_size
;
806 strm
->next_out
= out_buf
;
807 strm
->avail_out
= out_buf_size
;
809 ret
= inflateInit2(strm
, -12);
812 ret
= inflate(strm
, Z_FINISH
);
813 out_len
= strm
->next_out
- out_buf
;
814 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
815 out_len
!= out_buf_size
) {
823 int qcow2_decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
)
825 int ret
, csize
, nb_csectors
, sector_offset
;
828 coffset
= cluster_offset
& s
->cluster_offset_mask
;
829 if (s
->cluster_cache_offset
!= coffset
) {
830 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
831 sector_offset
= coffset
& 511;
832 csize
= nb_csectors
* 512 - sector_offset
;
833 ret
= bdrv_read(s
->hd
, coffset
>> 9, s
->cluster_data
, nb_csectors
);
837 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
838 s
->cluster_data
+ sector_offset
, csize
) < 0) {
841 s
->cluster_cache_offset
= coffset
;