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 ret
= bdrv_pwrite(s
->hd
, offsetof(QCowHeader
, l1_size
), data
,sizeof(data
));
71 if (ret
!= sizeof(data
)) {
74 qemu_free(s
->l1_table
);
75 qcow2_free_clusters(bs
, s
->l1_table_offset
, s
->l1_size
* sizeof(uint64_t));
76 s
->l1_table_offset
= new_l1_table_offset
;
77 s
->l1_table
= new_l1_table
;
78 s
->l1_size
= new_l1_size
;
81 qemu_free(new_l1_table
);
82 qcow2_free_clusters(bs
, new_l1_table_offset
, new_l1_size2
);
83 return ret
< 0 ? ret
: -EIO
;
86 void qcow2_l2_cache_reset(BlockDriverState
*bs
)
88 BDRVQcowState
*s
= bs
->opaque
;
90 memset(s
->l2_cache
, 0, s
->l2_size
* L2_CACHE_SIZE
* sizeof(uint64_t));
91 memset(s
->l2_cache_offsets
, 0, L2_CACHE_SIZE
* sizeof(uint64_t));
92 memset(s
->l2_cache_counts
, 0, L2_CACHE_SIZE
* sizeof(uint32_t));
95 static inline int l2_cache_new_entry(BlockDriverState
*bs
)
97 BDRVQcowState
*s
= bs
->opaque
;
101 /* find a new entry in the least used one */
103 min_count
= 0xffffffff;
104 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
105 if (s
->l2_cache_counts
[i
] < min_count
) {
106 min_count
= s
->l2_cache_counts
[i
];
116 * seek l2_offset in the l2_cache table
117 * if not found, return NULL,
119 * increments the l2 cache hit count of the entry,
120 * if counter overflow, divide by two all counters
121 * return the pointer to the l2 cache entry
125 static uint64_t *seek_l2_table(BDRVQcowState
*s
, uint64_t l2_offset
)
129 for(i
= 0; i
< L2_CACHE_SIZE
; i
++) {
130 if (l2_offset
== s
->l2_cache_offsets
[i
]) {
131 /* increment the hit count */
132 if (++s
->l2_cache_counts
[i
] == 0xffffffff) {
133 for(j
= 0; j
< L2_CACHE_SIZE
; j
++) {
134 s
->l2_cache_counts
[j
] >>= 1;
137 return s
->l2_cache
+ (i
<< s
->l2_bits
);
146 * Loads a L2 table into memory. If the table is in the cache, the cache
147 * is used; otherwise the L2 table is loaded from the image file.
149 * Returns a pointer to the L2 table on success, or NULL if the read from
150 * the image file failed.
153 static uint64_t *l2_load(BlockDriverState
*bs
, uint64_t l2_offset
)
155 BDRVQcowState
*s
= bs
->opaque
;
159 /* seek if the table for the given offset is in the cache */
161 l2_table
= seek_l2_table(s
, l2_offset
);
162 if (l2_table
!= NULL
)
165 /* not found: load a new entry in the least used one */
167 min_index
= l2_cache_new_entry(bs
);
168 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
169 if (bdrv_pread(s
->hd
, l2_offset
, l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
170 s
->l2_size
* sizeof(uint64_t))
172 s
->l2_cache_offsets
[min_index
] = l2_offset
;
173 s
->l2_cache_counts
[min_index
] = 1;
179 * Writes one sector of the L1 table to the disk (can't update single entries
180 * and we really don't want bdrv_pread to perform a read-modify-write)
182 #define L1_ENTRIES_PER_SECTOR (512 / 8)
183 static int write_l1_entry(BDRVQcowState
*s
, int l1_index
)
185 uint64_t buf
[L1_ENTRIES_PER_SECTOR
];
189 l1_start_index
= l1_index
& ~(L1_ENTRIES_PER_SECTOR
- 1);
190 for (i
= 0; i
< L1_ENTRIES_PER_SECTOR
; i
++) {
191 buf
[i
] = cpu_to_be64(s
->l1_table
[l1_start_index
+ i
]);
194 if (bdrv_pwrite(s
->hd
, s
->l1_table_offset
+ 8 * l1_start_index
,
195 buf
, sizeof(buf
)) != sizeof(buf
))
206 * Allocate a new l2 entry in the file. If l1_index points to an already
207 * used entry in the L2 table (i.e. we are doing a copy on write for the L2
208 * table) copy the contents of the old L2 table into the newly allocated one.
209 * Otherwise the new table is initialized with zeros.
213 static uint64_t *l2_allocate(BlockDriverState
*bs
, int l1_index
)
215 BDRVQcowState
*s
= bs
->opaque
;
217 uint64_t old_l2_offset
;
218 uint64_t *l2_table
, l2_offset
;
220 old_l2_offset
= s
->l1_table
[l1_index
];
222 /* allocate a new l2 entry */
224 l2_offset
= qcow2_alloc_clusters(bs
, s
->l2_size
* sizeof(uint64_t));
226 /* update the L1 entry */
228 s
->l1_table
[l1_index
] = l2_offset
| QCOW_OFLAG_COPIED
;
229 if (write_l1_entry(s
, l1_index
) < 0) {
233 /* allocate a new entry in the l2 cache */
235 min_index
= l2_cache_new_entry(bs
);
236 l2_table
= s
->l2_cache
+ (min_index
<< s
->l2_bits
);
238 if (old_l2_offset
== 0) {
239 /* if there was no old l2 table, clear the new table */
240 memset(l2_table
, 0, s
->l2_size
* sizeof(uint64_t));
242 /* if there was an old l2 table, read it from the disk */
243 if (bdrv_pread(s
->hd
, old_l2_offset
,
244 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
245 s
->l2_size
* sizeof(uint64_t))
248 /* write the l2 table to the file */
249 if (bdrv_pwrite(s
->hd
, l2_offset
,
250 l2_table
, s
->l2_size
* sizeof(uint64_t)) !=
251 s
->l2_size
* sizeof(uint64_t))
254 /* update the l2 cache entry */
256 s
->l2_cache_offsets
[min_index
] = l2_offset
;
257 s
->l2_cache_counts
[min_index
] = 1;
262 static int count_contiguous_clusters(uint64_t nb_clusters
, int cluster_size
,
263 uint64_t *l2_table
, uint64_t start
, uint64_t mask
)
266 uint64_t offset
= be64_to_cpu(l2_table
[0]) & ~mask
;
271 for (i
= start
; i
< start
+ nb_clusters
; i
++)
272 if (offset
+ (uint64_t) i
* cluster_size
!= (be64_to_cpu(l2_table
[i
]) & ~mask
))
278 static int count_contiguous_free_clusters(uint64_t nb_clusters
, uint64_t *l2_table
)
282 while(nb_clusters
-- && l2_table
[i
] == 0)
288 /* The crypt function is compatible with the linux cryptoloop
289 algorithm for < 4 GB images. NOTE: out_buf == in_buf is
291 void qcow2_encrypt_sectors(BDRVQcowState
*s
, int64_t sector_num
,
292 uint8_t *out_buf
, const uint8_t *in_buf
,
293 int nb_sectors
, int enc
,
302 for(i
= 0; i
< nb_sectors
; i
++) {
303 ivec
.ll
[0] = cpu_to_le64(sector_num
);
305 AES_cbc_encrypt(in_buf
, out_buf
, 512, key
,
314 static int qcow_read(BlockDriverState
*bs
, int64_t sector_num
,
315 uint8_t *buf
, int nb_sectors
)
317 BDRVQcowState
*s
= bs
->opaque
;
318 int ret
, index_in_cluster
, n
, n1
;
319 uint64_t cluster_offset
;
321 while (nb_sectors
> 0) {
323 cluster_offset
= qcow2_get_cluster_offset(bs
, sector_num
<< 9, &n
);
324 index_in_cluster
= sector_num
& (s
->cluster_sectors
- 1);
325 if (!cluster_offset
) {
326 if (bs
->backing_hd
) {
327 /* read from the base image */
328 n1
= qcow2_backing_read1(bs
->backing_hd
, sector_num
, buf
, n
);
330 ret
= bdrv_read(bs
->backing_hd
, sector_num
, buf
, n1
);
335 memset(buf
, 0, 512 * n
);
337 } else if (cluster_offset
& QCOW_OFLAG_COMPRESSED
) {
338 if (qcow2_decompress_cluster(s
, cluster_offset
) < 0)
340 memcpy(buf
, s
->cluster_cache
+ index_in_cluster
* 512, 512 * n
);
342 ret
= bdrv_pread(s
->hd
, cluster_offset
+ index_in_cluster
* 512, buf
, n
* 512);
345 if (s
->crypt_method
) {
346 qcow2_encrypt_sectors(s
, sector_num
, buf
, buf
, n
, 0,
347 &s
->aes_decrypt_key
);
357 static int copy_sectors(BlockDriverState
*bs
, uint64_t start_sect
,
358 uint64_t cluster_offset
, int n_start
, int n_end
)
360 BDRVQcowState
*s
= bs
->opaque
;
366 ret
= qcow_read(bs
, start_sect
+ n_start
, s
->cluster_data
, n
);
369 if (s
->crypt_method
) {
370 qcow2_encrypt_sectors(s
, start_sect
+ n_start
,
372 s
->cluster_data
, n
, 1,
373 &s
->aes_encrypt_key
);
375 ret
= bdrv_write(s
->hd
, (cluster_offset
>> 9) + n_start
,
386 * For a given offset of the disk image, return cluster offset in
389 * on entry, *num is the number of contiguous clusters we'd like to
390 * access following offset.
392 * on exit, *num is the number of contiguous clusters we can read.
394 * Return 1, if the offset is found
395 * Return 0, otherwise.
399 uint64_t qcow2_get_cluster_offset(BlockDriverState
*bs
, uint64_t offset
,
402 BDRVQcowState
*s
= bs
->opaque
;
403 unsigned int l1_index
, l2_index
;
404 uint64_t l2_offset
, *l2_table
, cluster_offset
;
406 unsigned int index_in_cluster
, nb_clusters
;
407 uint64_t nb_available
, nb_needed
;
409 index_in_cluster
= (offset
>> 9) & (s
->cluster_sectors
- 1);
410 nb_needed
= *num
+ index_in_cluster
;
412 l1_bits
= s
->l2_bits
+ s
->cluster_bits
;
414 /* compute how many bytes there are between the offset and
415 * the end of the l1 entry
418 nb_available
= (1ULL << l1_bits
) - (offset
& ((1ULL << l1_bits
) - 1));
420 /* compute the number of available sectors */
422 nb_available
= (nb_available
>> 9) + index_in_cluster
;
424 if (nb_needed
> nb_available
) {
425 nb_needed
= nb_available
;
430 /* seek the the l2 offset in the l1 table */
432 l1_index
= offset
>> l1_bits
;
433 if (l1_index
>= s
->l1_size
)
436 l2_offset
= s
->l1_table
[l1_index
];
438 /* seek the l2 table of the given l2 offset */
443 /* load the l2 table in memory */
445 l2_offset
&= ~QCOW_OFLAG_COPIED
;
446 l2_table
= l2_load(bs
, l2_offset
);
447 if (l2_table
== NULL
)
450 /* find the cluster offset for the given disk offset */
452 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
453 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
454 nb_clusters
= size_to_clusters(s
, nb_needed
<< 9);
456 if (!cluster_offset
) {
457 /* how many empty clusters ? */
458 c
= count_contiguous_free_clusters(nb_clusters
, &l2_table
[l2_index
]);
460 /* how many allocated clusters ? */
461 c
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
462 &l2_table
[l2_index
], 0, QCOW_OFLAG_COPIED
);
465 nb_available
= (c
* s
->cluster_sectors
);
467 if (nb_available
> nb_needed
)
468 nb_available
= nb_needed
;
470 *num
= nb_available
- index_in_cluster
;
472 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
478 * for a given disk offset, load (and allocate if needed)
481 * the l2 table offset in the qcow2 file and the cluster index
482 * in the l2 table are given to the caller.
484 * Returns 0 on success, -errno in failure case
486 static int get_cluster_table(BlockDriverState
*bs
, uint64_t offset
,
487 uint64_t **new_l2_table
,
488 uint64_t *new_l2_offset
,
491 BDRVQcowState
*s
= bs
->opaque
;
492 unsigned int l1_index
, l2_index
;
493 uint64_t l2_offset
, *l2_table
;
496 /* seek the the l2 offset in the l1 table */
498 l1_index
= offset
>> (s
->l2_bits
+ s
->cluster_bits
);
499 if (l1_index
>= s
->l1_size
) {
500 ret
= qcow2_grow_l1_table(bs
, l1_index
+ 1);
505 l2_offset
= s
->l1_table
[l1_index
];
507 /* seek the l2 table of the given l2 offset */
509 if (l2_offset
& QCOW_OFLAG_COPIED
) {
510 /* load the l2 table in memory */
511 l2_offset
&= ~QCOW_OFLAG_COPIED
;
512 l2_table
= l2_load(bs
, l2_offset
);
513 if (l2_table
== NULL
) {
518 qcow2_free_clusters(bs
, l2_offset
, s
->l2_size
* sizeof(uint64_t));
519 l2_table
= l2_allocate(bs
, l1_index
);
520 if (l2_table
== NULL
) {
523 l2_offset
= s
->l1_table
[l1_index
] & ~QCOW_OFLAG_COPIED
;
526 /* find the cluster offset for the given disk offset */
528 l2_index
= (offset
>> s
->cluster_bits
) & (s
->l2_size
- 1);
530 *new_l2_table
= l2_table
;
531 *new_l2_offset
= l2_offset
;
532 *new_l2_index
= l2_index
;
538 * alloc_compressed_cluster_offset
540 * For a given offset of the disk image, return cluster offset in
543 * If the offset is not found, allocate a new compressed cluster.
545 * Return the cluster offset if successful,
546 * Return 0, otherwise.
550 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState
*bs
,
554 BDRVQcowState
*s
= bs
->opaque
;
556 uint64_t l2_offset
, *l2_table
, cluster_offset
;
559 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
564 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
565 if (cluster_offset
& QCOW_OFLAG_COPIED
)
566 return cluster_offset
& ~QCOW_OFLAG_COPIED
;
569 qcow2_free_any_clusters(bs
, cluster_offset
, 1);
571 cluster_offset
= qcow2_alloc_bytes(bs
, compressed_size
);
572 nb_csectors
= ((cluster_offset
+ compressed_size
- 1) >> 9) -
573 (cluster_offset
>> 9);
575 cluster_offset
|= QCOW_OFLAG_COMPRESSED
|
576 ((uint64_t)nb_csectors
<< s
->csize_shift
);
578 /* update L2 table */
580 /* compressed clusters never have the copied flag */
582 l2_table
[l2_index
] = cpu_to_be64(cluster_offset
);
583 if (bdrv_pwrite(s
->hd
,
584 l2_offset
+ l2_index
* sizeof(uint64_t),
586 sizeof(uint64_t)) != sizeof(uint64_t))
589 return cluster_offset
;
593 * Write L2 table updates to disk, writing whole sectors to avoid a
594 * read-modify-write in bdrv_pwrite
596 #define L2_ENTRIES_PER_SECTOR (512 / 8)
597 static int write_l2_entries(BDRVQcowState
*s
, uint64_t *l2_table
,
598 uint64_t l2_offset
, int l2_index
, int num
)
600 int l2_start_index
= l2_index
& ~(L1_ENTRIES_PER_SECTOR
- 1);
601 int start_offset
= (8 * l2_index
) & ~511;
602 int end_offset
= (8 * (l2_index
+ num
) + 511) & ~511;
603 size_t len
= end_offset
- start_offset
;
605 if (bdrv_pwrite(s
->hd
, l2_offset
+ start_offset
, &l2_table
[l2_start_index
],
614 int qcow2_alloc_cluster_link_l2(BlockDriverState
*bs
, QCowL2Meta
*m
)
616 BDRVQcowState
*s
= bs
->opaque
;
617 int i
, j
= 0, l2_index
, ret
;
618 uint64_t *old_cluster
, start_sect
, l2_offset
, *l2_table
;
619 uint64_t cluster_offset
= m
->cluster_offset
;
621 if (m
->nb_clusters
== 0)
624 old_cluster
= qemu_malloc(m
->nb_clusters
* sizeof(uint64_t));
626 /* copy content of unmodified sectors */
627 start_sect
= (m
->offset
& ~(s
->cluster_size
- 1)) >> 9;
629 ret
= copy_sectors(bs
, start_sect
, cluster_offset
, 0, m
->n_start
);
634 if (m
->nb_available
& (s
->cluster_sectors
- 1)) {
635 uint64_t end
= m
->nb_available
& ~(uint64_t)(s
->cluster_sectors
- 1);
636 ret
= copy_sectors(bs
, start_sect
+ end
, cluster_offset
+ (end
<< 9),
637 m
->nb_available
- end
, s
->cluster_sectors
);
642 /* update L2 table */
643 ret
= get_cluster_table(bs
, m
->offset
, &l2_table
, &l2_offset
, &l2_index
);
648 for (i
= 0; i
< m
->nb_clusters
; i
++) {
649 /* if two concurrent writes happen to the same unallocated cluster
650 * each write allocates separate cluster and writes data concurrently.
651 * The first one to complete updates l2 table with pointer to its
652 * cluster the second one has to do RMW (which is done above by
653 * copy_sectors()), update l2 table with its cluster pointer and free
654 * old cluster. This is what this loop does */
655 if(l2_table
[l2_index
+ i
] != 0)
656 old_cluster
[j
++] = l2_table
[l2_index
+ i
];
658 l2_table
[l2_index
+ i
] = cpu_to_be64((cluster_offset
+
659 (i
<< s
->cluster_bits
)) | QCOW_OFLAG_COPIED
);
662 if (write_l2_entries(s
, l2_table
, l2_offset
, l2_index
, m
->nb_clusters
) < 0) {
667 for (i
= 0; i
< j
; i
++)
668 qcow2_free_any_clusters(bs
,
669 be64_to_cpu(old_cluster
[i
]) & ~QCOW_OFLAG_COPIED
, 1);
673 qemu_free(old_cluster
);
678 * alloc_cluster_offset
680 * For a given offset of the disk image, return cluster offset in qcow2 file.
681 * If the offset is not found, allocate a new cluster.
683 * If the cluster was already allocated, m->nb_clusters is set to 0,
684 * m->depends_on is set to NULL and the other fields in m are meaningless.
686 * If the cluster is newly allocated, m->nb_clusters is set to the number of
687 * contiguous clusters that have been allocated. This may be 0 if the request
688 * conflict with another write request in flight; in this case, m->depends_on
689 * is set and the remaining fields of m are meaningless.
691 * If m->nb_clusters is non-zero, the other fields of m are valid and contain
692 * information about the first allocated cluster.
694 * Return 0 on success and -errno in error cases
696 uint64_t qcow2_alloc_cluster_offset(BlockDriverState
*bs
,
698 int n_start
, int n_end
,
699 int *num
, QCowL2Meta
*m
)
701 BDRVQcowState
*s
= bs
->opaque
;
703 uint64_t l2_offset
, *l2_table
, cluster_offset
;
704 unsigned int nb_clusters
, i
= 0;
705 QCowL2Meta
*old_alloc
;
707 ret
= get_cluster_table(bs
, offset
, &l2_table
, &l2_offset
, &l2_index
);
712 nb_clusters
= size_to_clusters(s
, n_end
<< 9);
714 nb_clusters
= MIN(nb_clusters
, s
->l2_size
- l2_index
);
716 cluster_offset
= be64_to_cpu(l2_table
[l2_index
]);
718 /* We keep all QCOW_OFLAG_COPIED clusters */
720 if (cluster_offset
& QCOW_OFLAG_COPIED
) {
721 nb_clusters
= count_contiguous_clusters(nb_clusters
, s
->cluster_size
,
722 &l2_table
[l2_index
], 0, 0);
724 cluster_offset
&= ~QCOW_OFLAG_COPIED
;
726 m
->depends_on
= NULL
;
731 /* for the moment, multiple compressed clusters are not managed */
733 if (cluster_offset
& QCOW_OFLAG_COMPRESSED
)
736 /* how many available clusters ? */
738 while (i
< nb_clusters
) {
739 i
+= count_contiguous_clusters(nb_clusters
- i
, s
->cluster_size
,
740 &l2_table
[l2_index
], i
, 0);
742 if(be64_to_cpu(l2_table
[l2_index
+ i
]))
745 i
+= count_contiguous_free_clusters(nb_clusters
- i
,
746 &l2_table
[l2_index
+ i
]);
748 cluster_offset
= be64_to_cpu(l2_table
[l2_index
+ i
]);
750 if ((cluster_offset
& QCOW_OFLAG_COPIED
) ||
751 (cluster_offset
& QCOW_OFLAG_COMPRESSED
))
757 * Check if there already is an AIO write request in flight which allocates
758 * the same cluster. In this case we need to wait until the previous
759 * request has completed and updated the L2 table accordingly.
761 QLIST_FOREACH(old_alloc
, &s
->cluster_allocs
, next_in_flight
) {
763 uint64_t end_offset
= offset
+ nb_clusters
* s
->cluster_size
;
764 uint64_t old_offset
= old_alloc
->offset
;
765 uint64_t old_end_offset
= old_alloc
->offset
+
766 old_alloc
->nb_clusters
* s
->cluster_size
;
768 if (end_offset
< old_offset
|| offset
> old_end_offset
) {
769 /* No intersection */
771 if (offset
< old_offset
) {
772 /* Stop at the start of a running allocation */
773 nb_clusters
= (old_offset
- offset
) >> s
->cluster_bits
;
778 if (nb_clusters
== 0) {
779 /* Set dependency and wait for a callback */
780 m
->depends_on
= old_alloc
;
792 QLIST_INSERT_HEAD(&s
->cluster_allocs
, m
, next_in_flight
);
794 /* allocate a new cluster */
796 cluster_offset
= qcow2_alloc_clusters(bs
, nb_clusters
* s
->cluster_size
);
798 /* save info needed for meta data update */
800 m
->n_start
= n_start
;
801 m
->nb_clusters
= nb_clusters
;
804 m
->nb_available
= MIN(nb_clusters
<< (s
->cluster_bits
- 9), n_end
);
805 m
->cluster_offset
= cluster_offset
;
807 *num
= m
->nb_available
- n_start
;
812 static int decompress_buffer(uint8_t *out_buf
, int out_buf_size
,
813 const uint8_t *buf
, int buf_size
)
815 z_stream strm1
, *strm
= &strm1
;
818 memset(strm
, 0, sizeof(*strm
));
820 strm
->next_in
= (uint8_t *)buf
;
821 strm
->avail_in
= buf_size
;
822 strm
->next_out
= out_buf
;
823 strm
->avail_out
= out_buf_size
;
825 ret
= inflateInit2(strm
, -12);
828 ret
= inflate(strm
, Z_FINISH
);
829 out_len
= strm
->next_out
- out_buf
;
830 if ((ret
!= Z_STREAM_END
&& ret
!= Z_BUF_ERROR
) ||
831 out_len
!= out_buf_size
) {
839 int qcow2_decompress_cluster(BDRVQcowState
*s
, uint64_t cluster_offset
)
841 int ret
, csize
, nb_csectors
, sector_offset
;
844 coffset
= cluster_offset
& s
->cluster_offset_mask
;
845 if (s
->cluster_cache_offset
!= coffset
) {
846 nb_csectors
= ((cluster_offset
>> s
->csize_shift
) & s
->csize_mask
) + 1;
847 sector_offset
= coffset
& 511;
848 csize
= nb_csectors
* 512 - sector_offset
;
849 ret
= bdrv_read(s
->hd
, coffset
>> 9, s
->cluster_data
, nb_csectors
);
853 if (decompress_buffer(s
->cluster_cache
, s
->cluster_size
,
854 s
->cluster_data
+ sector_offset
, csize
) < 0) {
857 s
->cluster_cache_offset
= coffset
;