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
25 #include "qemu/osdep.h"
26 #include "qapi/error.h"
27 #include "qemu-common.h"
28 #include "block/block_int.h"
30 #include "qemu/range.h"
31 #include "qemu/bswap.h"
32 #include "qemu/cutils.h"
34 static int64_t alloc_clusters_noref(BlockDriverState
*bs
, uint64_t size
,
36 static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState
*bs
,
37 int64_t offset
, int64_t length
, uint64_t addend
,
38 bool decrease
, enum qcow2_discard_type type
);
40 static uint64_t get_refcount_ro0(const void *refcount_array
, uint64_t index
);
41 static uint64_t get_refcount_ro1(const void *refcount_array
, uint64_t index
);
42 static uint64_t get_refcount_ro2(const void *refcount_array
, uint64_t index
);
43 static uint64_t get_refcount_ro3(const void *refcount_array
, uint64_t index
);
44 static uint64_t get_refcount_ro4(const void *refcount_array
, uint64_t index
);
45 static uint64_t get_refcount_ro5(const void *refcount_array
, uint64_t index
);
46 static uint64_t get_refcount_ro6(const void *refcount_array
, uint64_t index
);
48 static void set_refcount_ro0(void *refcount_array
, uint64_t index
,
50 static void set_refcount_ro1(void *refcount_array
, uint64_t index
,
52 static void set_refcount_ro2(void *refcount_array
, uint64_t index
,
54 static void set_refcount_ro3(void *refcount_array
, uint64_t index
,
56 static void set_refcount_ro4(void *refcount_array
, uint64_t index
,
58 static void set_refcount_ro5(void *refcount_array
, uint64_t index
,
60 static void set_refcount_ro6(void *refcount_array
, uint64_t index
,
64 static Qcow2GetRefcountFunc
*const get_refcount_funcs
[] = {
74 static Qcow2SetRefcountFunc
*const set_refcount_funcs
[] = {
85 /*********************************************************/
86 /* refcount handling */
88 static void update_max_refcount_table_index(BDRVQcow2State
*s
)
90 unsigned i
= s
->refcount_table_size
- 1;
91 while (i
> 0 && (s
->refcount_table
[i
] & REFT_OFFSET_MASK
) == 0) {
94 /* Set s->max_refcount_table_index to the index of the last used entry */
95 s
->max_refcount_table_index
= i
;
98 int qcow2_refcount_init(BlockDriverState
*bs
)
100 BDRVQcow2State
*s
= bs
->opaque
;
101 unsigned int refcount_table_size2
, i
;
104 assert(s
->refcount_order
>= 0 && s
->refcount_order
<= 6);
106 s
->get_refcount
= get_refcount_funcs
[s
->refcount_order
];
107 s
->set_refcount
= set_refcount_funcs
[s
->refcount_order
];
109 assert(s
->refcount_table_size
<= INT_MAX
/ sizeof(uint64_t));
110 refcount_table_size2
= s
->refcount_table_size
* sizeof(uint64_t);
111 s
->refcount_table
= g_try_malloc(refcount_table_size2
);
113 if (s
->refcount_table_size
> 0) {
114 if (s
->refcount_table
== NULL
) {
118 BLKDBG_EVENT(bs
->file
, BLKDBG_REFTABLE_LOAD
);
119 ret
= bdrv_pread(bs
->file
, s
->refcount_table_offset
,
120 s
->refcount_table
, refcount_table_size2
);
124 for(i
= 0; i
< s
->refcount_table_size
; i
++)
125 be64_to_cpus(&s
->refcount_table
[i
]);
126 update_max_refcount_table_index(s
);
133 void qcow2_refcount_close(BlockDriverState
*bs
)
135 BDRVQcow2State
*s
= bs
->opaque
;
136 g_free(s
->refcount_table
);
140 static uint64_t get_refcount_ro0(const void *refcount_array
, uint64_t index
)
142 return (((const uint8_t *)refcount_array
)[index
/ 8] >> (index
% 8)) & 0x1;
145 static void set_refcount_ro0(void *refcount_array
, uint64_t index
,
148 assert(!(value
>> 1));
149 ((uint8_t *)refcount_array
)[index
/ 8] &= ~(0x1 << (index
% 8));
150 ((uint8_t *)refcount_array
)[index
/ 8] |= value
<< (index
% 8);
153 static uint64_t get_refcount_ro1(const void *refcount_array
, uint64_t index
)
155 return (((const uint8_t *)refcount_array
)[index
/ 4] >> (2 * (index
% 4)))
159 static void set_refcount_ro1(void *refcount_array
, uint64_t index
,
162 assert(!(value
>> 2));
163 ((uint8_t *)refcount_array
)[index
/ 4] &= ~(0x3 << (2 * (index
% 4)));
164 ((uint8_t *)refcount_array
)[index
/ 4] |= value
<< (2 * (index
% 4));
167 static uint64_t get_refcount_ro2(const void *refcount_array
, uint64_t index
)
169 return (((const uint8_t *)refcount_array
)[index
/ 2] >> (4 * (index
% 2)))
173 static void set_refcount_ro2(void *refcount_array
, uint64_t index
,
176 assert(!(value
>> 4));
177 ((uint8_t *)refcount_array
)[index
/ 2] &= ~(0xf << (4 * (index
% 2)));
178 ((uint8_t *)refcount_array
)[index
/ 2] |= value
<< (4 * (index
% 2));
181 static uint64_t get_refcount_ro3(const void *refcount_array
, uint64_t index
)
183 return ((const uint8_t *)refcount_array
)[index
];
186 static void set_refcount_ro3(void *refcount_array
, uint64_t index
,
189 assert(!(value
>> 8));
190 ((uint8_t *)refcount_array
)[index
] = value
;
193 static uint64_t get_refcount_ro4(const void *refcount_array
, uint64_t index
)
195 return be16_to_cpu(((const uint16_t *)refcount_array
)[index
]);
198 static void set_refcount_ro4(void *refcount_array
, uint64_t index
,
201 assert(!(value
>> 16));
202 ((uint16_t *)refcount_array
)[index
] = cpu_to_be16(value
);
205 static uint64_t get_refcount_ro5(const void *refcount_array
, uint64_t index
)
207 return be32_to_cpu(((const uint32_t *)refcount_array
)[index
]);
210 static void set_refcount_ro5(void *refcount_array
, uint64_t index
,
213 assert(!(value
>> 32));
214 ((uint32_t *)refcount_array
)[index
] = cpu_to_be32(value
);
217 static uint64_t get_refcount_ro6(const void *refcount_array
, uint64_t index
)
219 return be64_to_cpu(((const uint64_t *)refcount_array
)[index
]);
222 static void set_refcount_ro6(void *refcount_array
, uint64_t index
,
225 ((uint64_t *)refcount_array
)[index
] = cpu_to_be64(value
);
229 static int load_refcount_block(BlockDriverState
*bs
,
230 int64_t refcount_block_offset
,
231 void **refcount_block
)
233 BDRVQcow2State
*s
= bs
->opaque
;
235 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_LOAD
);
236 return qcow2_cache_get(bs
, s
->refcount_block_cache
, refcount_block_offset
,
241 * Retrieves the refcount of the cluster given by its index and stores it in
242 * *refcount. Returns 0 on success and -errno on failure.
244 int qcow2_get_refcount(BlockDriverState
*bs
, int64_t cluster_index
,
247 BDRVQcow2State
*s
= bs
->opaque
;
248 uint64_t refcount_table_index
, block_index
;
249 int64_t refcount_block_offset
;
251 void *refcount_block
;
253 refcount_table_index
= cluster_index
>> s
->refcount_block_bits
;
254 if (refcount_table_index
>= s
->refcount_table_size
) {
258 refcount_block_offset
=
259 s
->refcount_table
[refcount_table_index
] & REFT_OFFSET_MASK
;
260 if (!refcount_block_offset
) {
265 if (offset_into_cluster(s
, refcount_block_offset
)) {
266 qcow2_signal_corruption(bs
, true, -1, -1, "Refblock offset %#" PRIx64
267 " unaligned (reftable index: %#" PRIx64
")",
268 refcount_block_offset
, refcount_table_index
);
272 ret
= qcow2_cache_get(bs
, s
->refcount_block_cache
, refcount_block_offset
,
278 block_index
= cluster_index
& (s
->refcount_block_size
- 1);
279 *refcount
= s
->get_refcount(refcount_block
, block_index
);
281 qcow2_cache_put(s
->refcount_block_cache
, &refcount_block
);
286 /* Checks if two offsets are described by the same refcount block */
287 static int in_same_refcount_block(BDRVQcow2State
*s
, uint64_t offset_a
,
290 uint64_t block_a
= offset_a
>> (s
->cluster_bits
+ s
->refcount_block_bits
);
291 uint64_t block_b
= offset_b
>> (s
->cluster_bits
+ s
->refcount_block_bits
);
293 return (block_a
== block_b
);
297 * Loads a refcount block. If it doesn't exist yet, it is allocated first
298 * (including growing the refcount table if needed).
300 * Returns 0 on success or -errno in error case
302 static int alloc_refcount_block(BlockDriverState
*bs
,
303 int64_t cluster_index
, void **refcount_block
)
305 BDRVQcow2State
*s
= bs
->opaque
;
306 unsigned int refcount_table_index
;
309 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC
);
311 /* Find the refcount block for the given cluster */
312 refcount_table_index
= cluster_index
>> s
->refcount_block_bits
;
314 if (refcount_table_index
< s
->refcount_table_size
) {
316 uint64_t refcount_block_offset
=
317 s
->refcount_table
[refcount_table_index
] & REFT_OFFSET_MASK
;
319 /* If it's already there, we're done */
320 if (refcount_block_offset
) {
321 if (offset_into_cluster(s
, refcount_block_offset
)) {
322 qcow2_signal_corruption(bs
, true, -1, -1, "Refblock offset %#"
323 PRIx64
" unaligned (reftable index: "
324 "%#x)", refcount_block_offset
,
325 refcount_table_index
);
329 return load_refcount_block(bs
, refcount_block_offset
,
335 * If we came here, we need to allocate something. Something is at least
336 * a cluster for the new refcount block. It may also include a new refcount
337 * table if the old refcount table is too small.
339 * Note that allocating clusters here needs some special care:
341 * - We can't use the normal qcow2_alloc_clusters(), it would try to
342 * increase the refcount and very likely we would end up with an endless
343 * recursion. Instead we must place the refcount blocks in a way that
344 * they can describe them themselves.
346 * - We need to consider that at this point we are inside update_refcounts
347 * and potentially doing an initial refcount increase. This means that
348 * some clusters have already been allocated by the caller, but their
349 * refcount isn't accurate yet. If we allocate clusters for metadata, we
350 * need to return -EAGAIN to signal the caller that it needs to restart
351 * the search for free clusters.
353 * - alloc_clusters_noref and qcow2_free_clusters may load a different
354 * refcount block into the cache
357 *refcount_block
= NULL
;
359 /* We write to the refcount table, so we might depend on L2 tables */
360 ret
= qcow2_cache_flush(bs
, s
->l2_table_cache
);
365 /* Allocate the refcount block itself and mark it as used */
366 int64_t new_block
= alloc_clusters_noref(bs
, s
->cluster_size
, INT64_MAX
);
371 /* The offset must fit in the offset field of the refcount table entry */
372 assert((new_block
& REFT_OFFSET_MASK
) == new_block
);
374 /* If we're allocating the block at offset 0 then something is wrong */
375 if (new_block
== 0) {
376 qcow2_signal_corruption(bs
, true, -1, -1, "Preventing invalid "
377 "allocation of refcount block at offset 0");
382 fprintf(stderr
, "qcow2: Allocate refcount block %d for %" PRIx64
384 refcount_table_index
, cluster_index
<< s
->cluster_bits
, new_block
);
387 if (in_same_refcount_block(s
, new_block
, cluster_index
<< s
->cluster_bits
)) {
388 /* Zero the new refcount block before updating it */
389 ret
= qcow2_cache_get_empty(bs
, s
->refcount_block_cache
, new_block
,
395 memset(*refcount_block
, 0, s
->cluster_size
);
397 /* The block describes itself, need to update the cache */
398 int block_index
= (new_block
>> s
->cluster_bits
) &
399 (s
->refcount_block_size
- 1);
400 s
->set_refcount(*refcount_block
, block_index
, 1);
402 /* Described somewhere else. This can recurse at most twice before we
403 * arrive at a block that describes itself. */
404 ret
= update_refcount(bs
, new_block
, s
->cluster_size
, 1, false,
405 QCOW2_DISCARD_NEVER
);
410 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
415 /* Initialize the new refcount block only after updating its refcount,
416 * update_refcount uses the refcount cache itself */
417 ret
= qcow2_cache_get_empty(bs
, s
->refcount_block_cache
, new_block
,
423 memset(*refcount_block
, 0, s
->cluster_size
);
426 /* Now the new refcount block needs to be written to disk */
427 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC_WRITE
);
428 qcow2_cache_entry_mark_dirty(s
->refcount_block_cache
, *refcount_block
);
429 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
434 /* If the refcount table is big enough, just hook the block up there */
435 if (refcount_table_index
< s
->refcount_table_size
) {
436 uint64_t data64
= cpu_to_be64(new_block
);
437 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC_HOOKUP
);
438 ret
= bdrv_pwrite_sync(bs
->file
,
439 s
->refcount_table_offset
+ refcount_table_index
* sizeof(uint64_t),
440 &data64
, sizeof(data64
));
445 s
->refcount_table
[refcount_table_index
] = new_block
;
446 /* If there's a hole in s->refcount_table then it can happen
447 * that refcount_table_index < s->max_refcount_table_index */
448 s
->max_refcount_table_index
=
449 MAX(s
->max_refcount_table_index
, refcount_table_index
);
451 /* The new refcount block may be where the caller intended to put its
452 * data, so let it restart the search. */
456 qcow2_cache_put(s
->refcount_block_cache
, refcount_block
);
459 * If we come here, we need to grow the refcount table. Again, a new
460 * refcount table needs some space and we can't simply allocate to avoid
463 * Therefore let's grab new refcount blocks at the end of the image, which
464 * will describe themselves and the new refcount table. This way we can
465 * reference them only in the new table and do the switch to the new
466 * refcount table at once without producing an inconsistent state in
469 BLKDBG_EVENT(bs
->file
, BLKDBG_REFTABLE_GROW
);
471 /* Calculate the number of refcount blocks needed so far; this will be the
472 * basis for calculating the index of the first cluster used for the
473 * self-describing refcount structures which we are about to create.
475 * Because we reached this point, there cannot be any refcount entries for
476 * cluster_index or higher indices yet. However, because new_block has been
477 * allocated to describe that cluster (and it will assume this role later
478 * on), we cannot use that index; also, new_block may actually have a higher
479 * cluster index than cluster_index, so it needs to be taken into account
480 * here (and 1 needs to be added to its value because that cluster is used).
482 uint64_t blocks_used
= DIV_ROUND_UP(MAX(cluster_index
+ 1,
483 (new_block
>> s
->cluster_bits
) + 1),
484 s
->refcount_block_size
);
486 /* Create the new refcount table and blocks */
487 uint64_t meta_offset
= (blocks_used
* s
->refcount_block_size
) *
490 ret
= qcow2_refcount_area(bs
, meta_offset
, 0, false,
491 refcount_table_index
, new_block
);
496 ret
= load_refcount_block(bs
, new_block
, refcount_block
);
501 /* If we were trying to do the initial refcount update for some cluster
502 * allocation, we might have used the same clusters to store newly
503 * allocated metadata. Make the caller search some new space. */
507 if (*refcount_block
!= NULL
) {
508 qcow2_cache_put(s
->refcount_block_cache
, refcount_block
);
514 * Starting at @start_offset, this function creates new self-covering refcount
515 * structures: A new refcount table and refcount blocks which cover all of
516 * themselves, and a number of @additional_clusters beyond their end.
517 * @start_offset must be at the end of the image file, that is, there must be
518 * only empty space beyond it.
519 * If @exact_size is false, the refcount table will have 50 % more entries than
520 * necessary so it will not need to grow again soon.
521 * If @new_refblock_offset is not zero, it contains the offset of a refcount
522 * block that should be entered into the new refcount table at index
523 * @new_refblock_index.
525 * Returns: The offset after the new refcount structures (i.e. where the
526 * @additional_clusters may be placed) on success, -errno on error.
528 int64_t qcow2_refcount_area(BlockDriverState
*bs
, uint64_t start_offset
,
529 uint64_t additional_clusters
, bool exact_size
,
530 int new_refblock_index
,
531 uint64_t new_refblock_offset
)
533 BDRVQcow2State
*s
= bs
->opaque
;
534 uint64_t total_refblock_count_u64
, additional_refblock_count
;
535 int total_refblock_count
, table_size
, area_reftable_index
, table_clusters
;
537 uint64_t table_offset
, block_offset
, end_offset
;
541 assert(!(start_offset
% s
->cluster_size
));
543 qcow2_refcount_metadata_size(start_offset
/ s
->cluster_size
+
545 s
->cluster_size
, s
->refcount_order
,
546 !exact_size
, &total_refblock_count_u64
);
547 if (total_refblock_count_u64
> QCOW_MAX_REFTABLE_SIZE
) {
550 total_refblock_count
= total_refblock_count_u64
;
552 /* Index in the refcount table of the first refcount block to cover the area
553 * of refcount structures we are about to create; we know that
554 * @total_refblock_count can cover @start_offset, so this will definitely
555 * fit into an int. */
556 area_reftable_index
= (start_offset
/ s
->cluster_size
) /
557 s
->refcount_block_size
;
560 table_size
= total_refblock_count
;
562 table_size
= total_refblock_count
+
563 DIV_ROUND_UP(total_refblock_count
, 2);
565 /* The qcow2 file can only store the reftable size in number of clusters */
566 table_size
= ROUND_UP(table_size
, s
->cluster_size
/ sizeof(uint64_t));
567 table_clusters
= (table_size
* sizeof(uint64_t)) / s
->cluster_size
;
569 if (table_size
> QCOW_MAX_REFTABLE_SIZE
) {
573 new_table
= g_try_new0(uint64_t, table_size
);
575 assert(table_size
> 0);
576 if (new_table
== NULL
) {
581 /* Fill the new refcount table */
582 if (table_size
> s
->max_refcount_table_index
) {
583 /* We're actually growing the reftable */
584 memcpy(new_table
, s
->refcount_table
,
585 (s
->max_refcount_table_index
+ 1) * sizeof(uint64_t));
587 /* Improbable case: We're shrinking the reftable. However, the caller
588 * has assured us that there is only empty space beyond @start_offset,
589 * so we can simply drop all of the refblocks that won't fit into the
591 memcpy(new_table
, s
->refcount_table
, table_size
* sizeof(uint64_t));
594 if (new_refblock_offset
) {
595 assert(new_refblock_index
< total_refblock_count
);
596 new_table
[new_refblock_index
] = new_refblock_offset
;
599 /* Count how many new refblocks we have to create */
600 additional_refblock_count
= 0;
601 for (i
= area_reftable_index
; i
< total_refblock_count
; i
++) {
603 additional_refblock_count
++;
607 table_offset
= start_offset
+ additional_refblock_count
* s
->cluster_size
;
608 end_offset
= table_offset
+ table_clusters
* s
->cluster_size
;
610 /* Fill the refcount blocks, and create new ones, if necessary */
611 block_offset
= start_offset
;
612 for (i
= area_reftable_index
; i
< total_refblock_count
; i
++) {
614 uint64_t first_offset_covered
;
616 /* Reuse an existing refblock if possible, create a new one otherwise */
618 ret
= qcow2_cache_get(bs
, s
->refcount_block_cache
, new_table
[i
],
624 ret
= qcow2_cache_get_empty(bs
, s
->refcount_block_cache
,
625 block_offset
, &refblock_data
);
629 memset(refblock_data
, 0, s
->cluster_size
);
630 qcow2_cache_entry_mark_dirty(s
->refcount_block_cache
,
633 new_table
[i
] = block_offset
;
634 block_offset
+= s
->cluster_size
;
637 /* First host offset covered by this refblock */
638 first_offset_covered
= (uint64_t)i
* s
->refcount_block_size
*
640 if (first_offset_covered
< end_offset
) {
643 /* Set the refcount of all of the new refcount structures to 1 */
645 if (first_offset_covered
< start_offset
) {
646 assert(i
== area_reftable_index
);
647 j
= (start_offset
- first_offset_covered
) / s
->cluster_size
;
648 assert(j
< s
->refcount_block_size
);
653 end_index
= MIN((end_offset
- first_offset_covered
) /
655 s
->refcount_block_size
);
657 for (; j
< end_index
; j
++) {
658 /* The caller guaranteed us this space would be empty */
659 assert(s
->get_refcount(refblock_data
, j
) == 0);
660 s
->set_refcount(refblock_data
, j
, 1);
663 qcow2_cache_entry_mark_dirty(s
->refcount_block_cache
,
667 qcow2_cache_put(s
->refcount_block_cache
, &refblock_data
);
670 assert(block_offset
== table_offset
);
672 /* Write refcount blocks to disk */
673 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC_WRITE_BLOCKS
);
674 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
679 /* Write refcount table to disk */
680 for (i
= 0; i
< total_refblock_count
; i
++) {
681 cpu_to_be64s(&new_table
[i
]);
684 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC_WRITE_TABLE
);
685 ret
= bdrv_pwrite_sync(bs
->file
, table_offset
, new_table
,
686 table_size
* sizeof(uint64_t));
691 for (i
= 0; i
< total_refblock_count
; i
++) {
692 be64_to_cpus(&new_table
[i
]);
695 /* Hook up the new refcount table in the qcow2 header */
700 data
.d64
= cpu_to_be64(table_offset
);
701 data
.d32
= cpu_to_be32(table_clusters
);
702 BLKDBG_EVENT(bs
->file
, BLKDBG_REFBLOCK_ALLOC_SWITCH_TABLE
);
703 ret
= bdrv_pwrite_sync(bs
->file
,
704 offsetof(QCowHeader
, refcount_table_offset
),
705 &data
, sizeof(data
));
710 /* And switch it in memory */
711 uint64_t old_table_offset
= s
->refcount_table_offset
;
712 uint64_t old_table_size
= s
->refcount_table_size
;
714 g_free(s
->refcount_table
);
715 s
->refcount_table
= new_table
;
716 s
->refcount_table_size
= table_size
;
717 s
->refcount_table_offset
= table_offset
;
718 update_max_refcount_table_index(s
);
720 /* Free old table. */
721 qcow2_free_clusters(bs
, old_table_offset
, old_table_size
* sizeof(uint64_t),
722 QCOW2_DISCARD_OTHER
);
731 void qcow2_process_discards(BlockDriverState
*bs
, int ret
)
733 BDRVQcow2State
*s
= bs
->opaque
;
734 Qcow2DiscardRegion
*d
, *next
;
736 QTAILQ_FOREACH_SAFE(d
, &s
->discards
, next
, next
) {
737 QTAILQ_REMOVE(&s
->discards
, d
, next
);
739 /* Discard is optional, ignore the return value */
741 bdrv_pdiscard(bs
->file
, d
->offset
, d
->bytes
);
748 static void update_refcount_discard(BlockDriverState
*bs
,
749 uint64_t offset
, uint64_t length
)
751 BDRVQcow2State
*s
= bs
->opaque
;
752 Qcow2DiscardRegion
*d
, *p
, *next
;
754 QTAILQ_FOREACH(d
, &s
->discards
, next
) {
755 uint64_t new_start
= MIN(offset
, d
->offset
);
756 uint64_t new_end
= MAX(offset
+ length
, d
->offset
+ d
->bytes
);
758 if (new_end
- new_start
<= length
+ d
->bytes
) {
759 /* There can't be any overlap, areas ending up here have no
760 * references any more and therefore shouldn't get freed another
762 assert(d
->bytes
+ length
== new_end
- new_start
);
763 d
->offset
= new_start
;
764 d
->bytes
= new_end
- new_start
;
769 d
= g_malloc(sizeof(*d
));
770 *d
= (Qcow2DiscardRegion
) {
775 QTAILQ_INSERT_TAIL(&s
->discards
, d
, next
);
778 /* Merge discard requests if they are adjacent now */
779 QTAILQ_FOREACH_SAFE(p
, &s
->discards
, next
, next
) {
781 || p
->offset
> d
->offset
+ d
->bytes
782 || d
->offset
> p
->offset
+ p
->bytes
)
787 /* Still no overlap possible */
788 assert(p
->offset
== d
->offset
+ d
->bytes
789 || d
->offset
== p
->offset
+ p
->bytes
);
791 QTAILQ_REMOVE(&s
->discards
, p
, next
);
792 d
->offset
= MIN(d
->offset
, p
->offset
);
793 d
->bytes
+= p
->bytes
;
798 /* XXX: cache several refcount block clusters ? */
799 /* @addend is the absolute value of the addend; if @decrease is set, @addend
800 * will be subtracted from the current refcount, otherwise it will be added */
801 static int QEMU_WARN_UNUSED_RESULT
update_refcount(BlockDriverState
*bs
,
806 enum qcow2_discard_type type
)
808 BDRVQcow2State
*s
= bs
->opaque
;
809 int64_t start
, last
, cluster_offset
;
810 void *refcount_block
= NULL
;
811 int64_t old_table_index
= -1;
815 fprintf(stderr
, "update_refcount: offset=%" PRId64
" size=%" PRId64
816 " addend=%s%" PRIu64
"\n", offset
, length
, decrease
? "-" : "",
821 } else if (length
== 0) {
826 qcow2_cache_set_dependency(bs
, s
->refcount_block_cache
,
830 start
= start_of_cluster(s
, offset
);
831 last
= start_of_cluster(s
, offset
+ length
- 1);
832 for(cluster_offset
= start
; cluster_offset
<= last
;
833 cluster_offset
+= s
->cluster_size
)
837 int64_t cluster_index
= cluster_offset
>> s
->cluster_bits
;
838 int64_t table_index
= cluster_index
>> s
->refcount_block_bits
;
840 /* Load the refcount block and allocate it if needed */
841 if (table_index
!= old_table_index
) {
842 if (refcount_block
) {
843 qcow2_cache_put(s
->refcount_block_cache
, &refcount_block
);
845 ret
= alloc_refcount_block(bs
, cluster_index
, &refcount_block
);
846 /* If the caller needs to restart the search for free clusters,
847 * try the same ones first to see if they're still free. */
848 if (ret
== -EAGAIN
) {
849 if (s
->free_cluster_index
> (start
>> s
->cluster_bits
)) {
850 s
->free_cluster_index
= (start
>> s
->cluster_bits
);
857 old_table_index
= table_index
;
859 qcow2_cache_entry_mark_dirty(s
->refcount_block_cache
, refcount_block
);
861 /* we can update the count and save it */
862 block_index
= cluster_index
& (s
->refcount_block_size
- 1);
864 refcount
= s
->get_refcount(refcount_block
, block_index
);
865 if (decrease
? (refcount
- addend
> refcount
)
866 : (refcount
+ addend
< refcount
||
867 refcount
+ addend
> s
->refcount_max
))
877 if (refcount
== 0 && cluster_index
< s
->free_cluster_index
) {
878 s
->free_cluster_index
= cluster_index
;
880 s
->set_refcount(refcount_block
, block_index
, refcount
);
885 table
= qcow2_cache_is_table_offset(s
->refcount_block_cache
,
888 qcow2_cache_put(s
->refcount_block_cache
, &refcount_block
);
889 qcow2_cache_discard(s
->refcount_block_cache
, table
);
892 table
= qcow2_cache_is_table_offset(s
->l2_table_cache
, offset
);
894 qcow2_cache_discard(s
->l2_table_cache
, table
);
897 if (s
->discard_passthrough
[type
]) {
898 update_refcount_discard(bs
, cluster_offset
, s
->cluster_size
);
905 if (!s
->cache_discards
) {
906 qcow2_process_discards(bs
, ret
);
909 /* Write last changed block to disk */
910 if (refcount_block
) {
911 qcow2_cache_put(s
->refcount_block_cache
, &refcount_block
);
915 * Try do undo any updates if an error is returned (This may succeed in
916 * some cases like ENOSPC for allocating a new refcount block)
920 dummy
= update_refcount(bs
, offset
, cluster_offset
- offset
, addend
,
921 !decrease
, QCOW2_DISCARD_NEVER
);
929 * Increases or decreases the refcount of a given cluster.
931 * @addend is the absolute value of the addend; if @decrease is set, @addend
932 * will be subtracted from the current refcount, otherwise it will be added.
934 * On success 0 is returned; on failure -errno is returned.
936 int qcow2_update_cluster_refcount(BlockDriverState
*bs
,
937 int64_t cluster_index
,
938 uint64_t addend
, bool decrease
,
939 enum qcow2_discard_type type
)
941 BDRVQcow2State
*s
= bs
->opaque
;
944 ret
= update_refcount(bs
, cluster_index
<< s
->cluster_bits
, 1, addend
,
955 /*********************************************************/
956 /* cluster allocation functions */
960 /* return < 0 if error */
961 static int64_t alloc_clusters_noref(BlockDriverState
*bs
, uint64_t size
,
964 BDRVQcow2State
*s
= bs
->opaque
;
965 uint64_t i
, nb_clusters
, refcount
;
968 /* We can't allocate clusters if they may still be queued for discard. */
969 if (s
->cache_discards
) {
970 qcow2_process_discards(bs
, 0);
973 nb_clusters
= size_to_clusters(s
, size
);
975 for(i
= 0; i
< nb_clusters
; i
++) {
976 uint64_t next_cluster_index
= s
->free_cluster_index
++;
977 ret
= qcow2_get_refcount(bs
, next_cluster_index
, &refcount
);
981 } else if (refcount
!= 0) {
986 /* Make sure that all offsets in the "allocated" range are representable
987 * in the requested max */
988 if (s
->free_cluster_index
> 0 &&
989 s
->free_cluster_index
- 1 > (max
>> s
->cluster_bits
))
995 fprintf(stderr
, "alloc_clusters: size=%" PRId64
" -> %" PRId64
"\n",
997 (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
);
999 return (s
->free_cluster_index
- nb_clusters
) << s
->cluster_bits
;
1002 int64_t qcow2_alloc_clusters(BlockDriverState
*bs
, uint64_t size
)
1007 BLKDBG_EVENT(bs
->file
, BLKDBG_CLUSTER_ALLOC
);
1009 offset
= alloc_clusters_noref(bs
, size
, QCOW_MAX_CLUSTER_OFFSET
);
1014 ret
= update_refcount(bs
, offset
, size
, 1, false, QCOW2_DISCARD_NEVER
);
1015 } while (ret
== -EAGAIN
);
1024 int64_t qcow2_alloc_clusters_at(BlockDriverState
*bs
, uint64_t offset
,
1025 int64_t nb_clusters
)
1027 BDRVQcow2State
*s
= bs
->opaque
;
1028 uint64_t cluster_index
, refcount
;
1032 assert(nb_clusters
>= 0);
1033 if (nb_clusters
== 0) {
1038 /* Check how many clusters there are free */
1039 cluster_index
= offset
>> s
->cluster_bits
;
1040 for(i
= 0; i
< nb_clusters
; i
++) {
1041 ret
= qcow2_get_refcount(bs
, cluster_index
++, &refcount
);
1044 } else if (refcount
!= 0) {
1049 /* And then allocate them */
1050 ret
= update_refcount(bs
, offset
, i
<< s
->cluster_bits
, 1, false,
1051 QCOW2_DISCARD_NEVER
);
1052 } while (ret
== -EAGAIN
);
1061 /* only used to allocate compressed sectors. We try to allocate
1062 contiguous sectors. size must be <= cluster_size */
1063 int64_t qcow2_alloc_bytes(BlockDriverState
*bs
, int size
)
1065 BDRVQcow2State
*s
= bs
->opaque
;
1067 size_t free_in_cluster
;
1070 BLKDBG_EVENT(bs
->file
, BLKDBG_CLUSTER_ALLOC_BYTES
);
1071 assert(size
> 0 && size
<= s
->cluster_size
);
1072 assert(!s
->free_byte_offset
|| offset_into_cluster(s
, s
->free_byte_offset
));
1074 offset
= s
->free_byte_offset
;
1078 ret
= qcow2_get_refcount(bs
, offset
>> s
->cluster_bits
, &refcount
);
1083 if (refcount
== s
->refcount_max
) {
1088 free_in_cluster
= s
->cluster_size
- offset_into_cluster(s
, offset
);
1090 if (!offset
|| free_in_cluster
< size
) {
1091 int64_t new_cluster
;
1093 new_cluster
= alloc_clusters_noref(bs
, s
->cluster_size
,
1094 MIN(s
->cluster_offset_mask
,
1095 QCOW_MAX_CLUSTER_OFFSET
));
1096 if (new_cluster
< 0) {
1100 if (new_cluster
== 0) {
1101 qcow2_signal_corruption(bs
, true, -1, -1, "Preventing invalid "
1102 "allocation of compressed cluster "
1107 if (!offset
|| ROUND_UP(offset
, s
->cluster_size
) != new_cluster
) {
1108 offset
= new_cluster
;
1109 free_in_cluster
= s
->cluster_size
;
1111 free_in_cluster
+= s
->cluster_size
;
1116 ret
= update_refcount(bs
, offset
, size
, 1, false, QCOW2_DISCARD_NEVER
);
1120 } while (ret
== -EAGAIN
);
1125 /* The cluster refcount was incremented; refcount blocks must be flushed
1126 * before the caller's L2 table updates. */
1127 qcow2_cache_set_dependency(bs
, s
->l2_table_cache
, s
->refcount_block_cache
);
1129 s
->free_byte_offset
= offset
+ size
;
1130 if (!offset_into_cluster(s
, s
->free_byte_offset
)) {
1131 s
->free_byte_offset
= 0;
1137 void qcow2_free_clusters(BlockDriverState
*bs
,
1138 int64_t offset
, int64_t size
,
1139 enum qcow2_discard_type type
)
1143 BLKDBG_EVENT(bs
->file
, BLKDBG_CLUSTER_FREE
);
1144 ret
= update_refcount(bs
, offset
, size
, 1, true, type
);
1146 fprintf(stderr
, "qcow2_free_clusters failed: %s\n", strerror(-ret
));
1147 /* TODO Remember the clusters to free them later and avoid leaking */
1152 * Free a cluster using its L2 entry (handles clusters of all types, e.g.
1153 * normal cluster, compressed cluster, etc.)
1155 void qcow2_free_any_clusters(BlockDriverState
*bs
, uint64_t l2_entry
,
1156 int nb_clusters
, enum qcow2_discard_type type
)
1158 BDRVQcow2State
*s
= bs
->opaque
;
1160 switch (qcow2_get_cluster_type(l2_entry
)) {
1161 case QCOW2_CLUSTER_COMPRESSED
:
1164 nb_csectors
= ((l2_entry
>> s
->csize_shift
) &
1166 qcow2_free_clusters(bs
,
1167 (l2_entry
& s
->cluster_offset_mask
) & ~511,
1168 nb_csectors
* 512, type
);
1171 case QCOW2_CLUSTER_NORMAL
:
1172 case QCOW2_CLUSTER_ZERO_ALLOC
:
1173 if (offset_into_cluster(s
, l2_entry
& L2E_OFFSET_MASK
)) {
1174 qcow2_signal_corruption(bs
, false, -1, -1,
1175 "Cannot free unaligned cluster %#llx",
1176 l2_entry
& L2E_OFFSET_MASK
);
1178 qcow2_free_clusters(bs
, l2_entry
& L2E_OFFSET_MASK
,
1179 nb_clusters
<< s
->cluster_bits
, type
);
1182 case QCOW2_CLUSTER_ZERO_PLAIN
:
1183 case QCOW2_CLUSTER_UNALLOCATED
:
1190 int coroutine_fn
qcow2_write_caches(BlockDriverState
*bs
)
1192 BDRVQcow2State
*s
= bs
->opaque
;
1195 ret
= qcow2_cache_write(bs
, s
->l2_table_cache
);
1200 if (qcow2_need_accurate_refcounts(s
)) {
1201 ret
= qcow2_cache_write(bs
, s
->refcount_block_cache
);
1210 int coroutine_fn
qcow2_flush_caches(BlockDriverState
*bs
)
1212 int ret
= qcow2_write_caches(bs
);
1217 return bdrv_flush(bs
->file
->bs
);
1220 /*********************************************************/
1221 /* snapshots and image creation */
1225 /* update the refcounts of snapshots and the copied flag */
1226 int qcow2_update_snapshot_refcount(BlockDriverState
*bs
,
1227 int64_t l1_table_offset
, int l1_size
, int addend
)
1229 BDRVQcow2State
*s
= bs
->opaque
;
1230 uint64_t *l1_table
, *l2_slice
, l2_offset
, entry
, l1_size2
, refcount
;
1231 bool l1_allocated
= false;
1232 int64_t old_entry
, old_l2_offset
;
1233 unsigned slice
, slice_size2
, n_slices
;
1234 int i
, j
, l1_modified
= 0, nb_csectors
;
1237 assert(addend
>= -1 && addend
<= 1);
1241 l1_size2
= l1_size
* sizeof(uint64_t);
1242 slice_size2
= s
->l2_slice_size
* sizeof(uint64_t);
1243 n_slices
= s
->cluster_size
/ slice_size2
;
1245 s
->cache_discards
= true;
1247 /* WARNING: qcow2_snapshot_goto relies on this function not using the
1248 * l1_table_offset when it is the current s->l1_table_offset! Be careful
1249 * when changing this! */
1250 if (l1_table_offset
!= s
->l1_table_offset
) {
1251 l1_table
= g_try_malloc0(ROUND_UP(l1_size2
, 512));
1252 if (l1_size2
&& l1_table
== NULL
) {
1256 l1_allocated
= true;
1258 ret
= bdrv_pread(bs
->file
, l1_table_offset
, l1_table
, l1_size2
);
1263 for (i
= 0; i
< l1_size
; i
++) {
1264 be64_to_cpus(&l1_table
[i
]);
1267 assert(l1_size
== s
->l1_size
);
1268 l1_table
= s
->l1_table
;
1269 l1_allocated
= false;
1272 for (i
= 0; i
< l1_size
; i
++) {
1273 l2_offset
= l1_table
[i
];
1275 old_l2_offset
= l2_offset
;
1276 l2_offset
&= L1E_OFFSET_MASK
;
1278 if (offset_into_cluster(s
, l2_offset
)) {
1279 qcow2_signal_corruption(bs
, true, -1, -1, "L2 table offset %#"
1280 PRIx64
" unaligned (L1 index: %#x)",
1286 for (slice
= 0; slice
< n_slices
; slice
++) {
1287 ret
= qcow2_cache_get(bs
, s
->l2_table_cache
,
1288 l2_offset
+ slice
* slice_size2
,
1289 (void **) &l2_slice
);
1294 for (j
= 0; j
< s
->l2_slice_size
; j
++) {
1295 uint64_t cluster_index
;
1298 entry
= be64_to_cpu(l2_slice
[j
]);
1300 entry
&= ~QCOW_OFLAG_COPIED
;
1301 offset
= entry
& L2E_OFFSET_MASK
;
1303 switch (qcow2_get_cluster_type(entry
)) {
1304 case QCOW2_CLUSTER_COMPRESSED
:
1305 nb_csectors
= ((entry
>> s
->csize_shift
) &
1308 ret
= update_refcount(
1309 bs
, (entry
& s
->cluster_offset_mask
) & ~511,
1310 nb_csectors
* 512, abs(addend
), addend
< 0,
1311 QCOW2_DISCARD_SNAPSHOT
);
1316 /* compressed clusters are never modified */
1320 case QCOW2_CLUSTER_NORMAL
:
1321 case QCOW2_CLUSTER_ZERO_ALLOC
:
1322 if (offset_into_cluster(s
, offset
)) {
1323 /* Here l2_index means table (not slice) index */
1324 int l2_index
= slice
* s
->l2_slice_size
+ j
;
1325 qcow2_signal_corruption(
1326 bs
, true, -1, -1, "Cluster "
1327 "allocation offset %#" PRIx64
1328 " unaligned (L2 offset: %#"
1329 PRIx64
", L2 index: %#x)",
1330 offset
, l2_offset
, l2_index
);
1335 cluster_index
= offset
>> s
->cluster_bits
;
1336 assert(cluster_index
);
1338 ret
= qcow2_update_cluster_refcount(
1339 bs
, cluster_index
, abs(addend
), addend
< 0,
1340 QCOW2_DISCARD_SNAPSHOT
);
1346 ret
= qcow2_get_refcount(bs
, cluster_index
, &refcount
);
1352 case QCOW2_CLUSTER_ZERO_PLAIN
:
1353 case QCOW2_CLUSTER_UNALLOCATED
:
1361 if (refcount
== 1) {
1362 entry
|= QCOW_OFLAG_COPIED
;
1364 if (entry
!= old_entry
) {
1366 qcow2_cache_set_dependency(bs
, s
->l2_table_cache
,
1367 s
->refcount_block_cache
);
1369 l2_slice
[j
] = cpu_to_be64(entry
);
1370 qcow2_cache_entry_mark_dirty(s
->l2_table_cache
,
1375 qcow2_cache_put(s
->l2_table_cache
, (void **) &l2_slice
);
1379 ret
= qcow2_update_cluster_refcount(bs
, l2_offset
>>
1381 abs(addend
), addend
< 0,
1382 QCOW2_DISCARD_SNAPSHOT
);
1387 ret
= qcow2_get_refcount(bs
, l2_offset
>> s
->cluster_bits
,
1391 } else if (refcount
== 1) {
1392 l2_offset
|= QCOW_OFLAG_COPIED
;
1394 if (l2_offset
!= old_l2_offset
) {
1395 l1_table
[i
] = l2_offset
;
1401 ret
= bdrv_flush(bs
);
1404 qcow2_cache_put(s
->l2_table_cache
, (void **) &l2_slice
);
1407 s
->cache_discards
= false;
1408 qcow2_process_discards(bs
, ret
);
1410 /* Update L1 only if it isn't deleted anyway (addend = -1) */
1411 if (ret
== 0 && addend
>= 0 && l1_modified
) {
1412 for (i
= 0; i
< l1_size
; i
++) {
1413 cpu_to_be64s(&l1_table
[i
]);
1416 ret
= bdrv_pwrite_sync(bs
->file
, l1_table_offset
,
1417 l1_table
, l1_size2
);
1419 for (i
= 0; i
< l1_size
; i
++) {
1420 be64_to_cpus(&l1_table
[i
]);
1431 /*********************************************************/
1432 /* refcount checking functions */
1435 static uint64_t refcount_array_byte_size(BDRVQcow2State
*s
, uint64_t entries
)
1437 /* This assertion holds because there is no way we can address more than
1438 * 2^(64 - 9) clusters at once (with cluster size 512 = 2^9, and because
1439 * offsets have to be representable in bytes); due to every cluster
1440 * corresponding to one refcount entry, we are well below that limit */
1441 assert(entries
< (UINT64_C(1) << (64 - 9)));
1443 /* Thanks to the assertion this will not overflow, because
1444 * s->refcount_order < 7.
1445 * (note: x << s->refcount_order == x * s->refcount_bits) */
1446 return DIV_ROUND_UP(entries
<< s
->refcount_order
, 8);
1450 * Reallocates *array so that it can hold new_size entries. *size must contain
1451 * the current number of entries in *array. If the reallocation fails, *array
1452 * and *size will not be modified and -errno will be returned. If the
1453 * reallocation is successful, *array will be set to the new buffer, *size
1454 * will be set to new_size and 0 will be returned. The size of the reallocated
1455 * refcount array buffer will be aligned to a cluster boundary, and the newly
1456 * allocated area will be zeroed.
1458 static int realloc_refcount_array(BDRVQcow2State
*s
, void **array
,
1459 int64_t *size
, int64_t new_size
)
1461 int64_t old_byte_size
, new_byte_size
;
1464 /* Round to clusters so the array can be directly written to disk */
1465 old_byte_size
= size_to_clusters(s
, refcount_array_byte_size(s
, *size
))
1467 new_byte_size
= size_to_clusters(s
, refcount_array_byte_size(s
, new_size
))
1470 if (new_byte_size
== old_byte_size
) {
1475 assert(new_byte_size
> 0);
1477 if (new_byte_size
> SIZE_MAX
) {
1481 new_ptr
= g_try_realloc(*array
, new_byte_size
);
1486 if (new_byte_size
> old_byte_size
) {
1487 memset((char *)new_ptr
+ old_byte_size
, 0,
1488 new_byte_size
- old_byte_size
);
1498 * Increases the refcount for a range of clusters in a given refcount table.
1499 * This is used to construct a temporary refcount table out of L1 and L2 tables
1500 * which can be compared to the refcount table saved in the image.
1502 * Modifies the number of errors in res.
1504 int qcow2_inc_refcounts_imrt(BlockDriverState
*bs
, BdrvCheckResult
*res
,
1505 void **refcount_table
,
1506 int64_t *refcount_table_size
,
1507 int64_t offset
, int64_t size
)
1509 BDRVQcow2State
*s
= bs
->opaque
;
1510 uint64_t start
, last
, cluster_offset
, k
, refcount
;
1517 start
= start_of_cluster(s
, offset
);
1518 last
= start_of_cluster(s
, offset
+ size
- 1);
1519 for(cluster_offset
= start
; cluster_offset
<= last
;
1520 cluster_offset
+= s
->cluster_size
) {
1521 k
= cluster_offset
>> s
->cluster_bits
;
1522 if (k
>= *refcount_table_size
) {
1523 ret
= realloc_refcount_array(s
, refcount_table
,
1524 refcount_table_size
, k
+ 1);
1526 res
->check_errors
++;
1531 refcount
= s
->get_refcount(*refcount_table
, k
);
1532 if (refcount
== s
->refcount_max
) {
1533 fprintf(stderr
, "ERROR: overflow cluster offset=0x%" PRIx64
1534 "\n", cluster_offset
);
1535 fprintf(stderr
, "Use qemu-img amend to increase the refcount entry "
1536 "width or qemu-img convert to create a clean copy if the "
1537 "image cannot be opened for writing\n");
1541 s
->set_refcount(*refcount_table
, k
, refcount
+ 1);
1547 /* Flags for check_refcounts_l1() and check_refcounts_l2() */
1549 CHECK_FRAG_INFO
= 0x2, /* update BlockFragInfo counters */
1553 * Increases the refcount in the given refcount table for the all clusters
1554 * referenced in the L2 table. While doing so, performs some checks on L2
1557 * Returns the number of errors found by the checks or -errno if an internal
1560 static int check_refcounts_l2(BlockDriverState
*bs
, BdrvCheckResult
*res
,
1561 void **refcount_table
,
1562 int64_t *refcount_table_size
, int64_t l2_offset
,
1563 int flags
, BdrvCheckMode fix
)
1565 BDRVQcow2State
*s
= bs
->opaque
;
1566 uint64_t *l2_table
, l2_entry
;
1567 uint64_t next_contiguous_offset
= 0;
1568 int i
, l2_size
, nb_csectors
, ret
;
1570 /* Read L2 table from disk */
1571 l2_size
= s
->l2_size
* sizeof(uint64_t);
1572 l2_table
= g_malloc(l2_size
);
1574 ret
= bdrv_pread(bs
->file
, l2_offset
, l2_table
, l2_size
);
1576 fprintf(stderr
, "ERROR: I/O error in check_refcounts_l2\n");
1577 res
->check_errors
++;
1581 /* Do the actual checks */
1582 for(i
= 0; i
< s
->l2_size
; i
++) {
1583 l2_entry
= be64_to_cpu(l2_table
[i
]);
1585 switch (qcow2_get_cluster_type(l2_entry
)) {
1586 case QCOW2_CLUSTER_COMPRESSED
:
1587 /* Compressed clusters don't have QCOW_OFLAG_COPIED */
1588 if (l2_entry
& QCOW_OFLAG_COPIED
) {
1589 fprintf(stderr
, "ERROR: coffset=0x%" PRIx64
": "
1590 "copied flag must never be set for compressed "
1591 "clusters\n", l2_entry
& s
->cluster_offset_mask
);
1592 l2_entry
&= ~QCOW_OFLAG_COPIED
;
1596 /* Mark cluster as used */
1597 nb_csectors
= ((l2_entry
>> s
->csize_shift
) &
1599 l2_entry
&= s
->cluster_offset_mask
;
1600 ret
= qcow2_inc_refcounts_imrt(bs
, res
,
1601 refcount_table
, refcount_table_size
,
1602 l2_entry
& ~511, nb_csectors
* 512);
1607 if (flags
& CHECK_FRAG_INFO
) {
1608 res
->bfi
.allocated_clusters
++;
1609 res
->bfi
.compressed_clusters
++;
1611 /* Compressed clusters are fragmented by nature. Since they
1612 * take up sub-sector space but we only have sector granularity
1613 * I/O we need to re-read the same sectors even for adjacent
1614 * compressed clusters.
1616 res
->bfi
.fragmented_clusters
++;
1620 case QCOW2_CLUSTER_ZERO_ALLOC
:
1621 case QCOW2_CLUSTER_NORMAL
:
1623 uint64_t offset
= l2_entry
& L2E_OFFSET_MASK
;
1625 if (flags
& CHECK_FRAG_INFO
) {
1626 res
->bfi
.allocated_clusters
++;
1627 if (next_contiguous_offset
&&
1628 offset
!= next_contiguous_offset
) {
1629 res
->bfi
.fragmented_clusters
++;
1631 next_contiguous_offset
= offset
+ s
->cluster_size
;
1634 /* Correct offsets are cluster aligned */
1635 if (offset_into_cluster(s
, offset
)) {
1636 if (qcow2_get_cluster_type(l2_entry
) ==
1637 QCOW2_CLUSTER_ZERO_ALLOC
)
1639 fprintf(stderr
, "%s offset=%" PRIx64
": Preallocated zero "
1640 "cluster is not properly aligned; L2 entry "
1642 fix
& BDRV_FIX_ERRORS
? "Repairing" : "ERROR",
1644 if (fix
& BDRV_FIX_ERRORS
) {
1645 uint64_t l2e_offset
=
1646 l2_offset
+ (uint64_t)i
* sizeof(uint64_t);
1648 l2_entry
= QCOW_OFLAG_ZERO
;
1649 l2_table
[i
] = cpu_to_be64(l2_entry
);
1650 ret
= qcow2_pre_write_overlap_check(bs
,
1651 QCOW2_OL_ACTIVE_L2
| QCOW2_OL_INACTIVE_L2
,
1652 l2e_offset
, sizeof(uint64_t));
1654 fprintf(stderr
, "ERROR: Overlap check failed\n");
1655 res
->check_errors
++;
1656 /* Something is seriously wrong, so abort checking
1661 ret
= bdrv_pwrite_sync(bs
->file
, l2e_offset
,
1662 &l2_table
[i
], sizeof(uint64_t));
1664 fprintf(stderr
, "ERROR: Failed to overwrite L2 "
1665 "table entry: %s\n", strerror(-ret
));
1666 res
->check_errors
++;
1667 /* Do not abort, continue checking the rest of this
1668 * L2 table's entries */
1670 res
->corruptions_fixed
++;
1671 /* Skip marking the cluster as used
1672 * (it is unused now) */
1679 fprintf(stderr
, "ERROR offset=%" PRIx64
": Data cluster is "
1680 "not properly aligned; L2 entry corrupted.\n", offset
);
1685 /* Mark cluster as used */
1686 ret
= qcow2_inc_refcounts_imrt(bs
, res
,
1687 refcount_table
, refcount_table_size
,
1688 offset
, s
->cluster_size
);
1695 case QCOW2_CLUSTER_ZERO_PLAIN
:
1696 case QCOW2_CLUSTER_UNALLOCATED
:
1713 * Increases the refcount for the L1 table, its L2 tables and all referenced
1714 * clusters in the given refcount table. While doing so, performs some checks
1715 * on L1 and L2 entries.
1717 * Returns the number of errors found by the checks or -errno if an internal
1720 static int check_refcounts_l1(BlockDriverState
*bs
,
1721 BdrvCheckResult
*res
,
1722 void **refcount_table
,
1723 int64_t *refcount_table_size
,
1724 int64_t l1_table_offset
, int l1_size
,
1725 int flags
, BdrvCheckMode fix
)
1727 BDRVQcow2State
*s
= bs
->opaque
;
1728 uint64_t *l1_table
= NULL
, l2_offset
, l1_size2
;
1731 l1_size2
= l1_size
* sizeof(uint64_t);
1733 /* Mark L1 table as used */
1734 ret
= qcow2_inc_refcounts_imrt(bs
, res
, refcount_table
, refcount_table_size
,
1735 l1_table_offset
, l1_size2
);
1740 /* Read L1 table entries from disk */
1742 l1_table
= g_try_malloc(l1_size2
);
1743 if (l1_table
== NULL
) {
1745 res
->check_errors
++;
1748 ret
= bdrv_pread(bs
->file
, l1_table_offset
, l1_table
, l1_size2
);
1750 fprintf(stderr
, "ERROR: I/O error in check_refcounts_l1\n");
1751 res
->check_errors
++;
1754 for(i
= 0;i
< l1_size
; i
++)
1755 be64_to_cpus(&l1_table
[i
]);
1758 /* Do the actual checks */
1759 for(i
= 0; i
< l1_size
; i
++) {
1760 l2_offset
= l1_table
[i
];
1762 /* Mark L2 table as used */
1763 l2_offset
&= L1E_OFFSET_MASK
;
1764 ret
= qcow2_inc_refcounts_imrt(bs
, res
,
1765 refcount_table
, refcount_table_size
,
1766 l2_offset
, s
->cluster_size
);
1771 /* L2 tables are cluster aligned */
1772 if (offset_into_cluster(s
, l2_offset
)) {
1773 fprintf(stderr
, "ERROR l2_offset=%" PRIx64
": Table is not "
1774 "cluster aligned; L1 entry corrupted\n", l2_offset
);
1778 /* Process and check L2 entries */
1779 ret
= check_refcounts_l2(bs
, res
, refcount_table
,
1780 refcount_table_size
, l2_offset
, flags
,
1796 * Checks the OFLAG_COPIED flag for all L1 and L2 entries.
1798 * This function does not print an error message nor does it increment
1799 * check_errors if qcow2_get_refcount fails (this is because such an error will
1800 * have been already detected and sufficiently signaled by the calling function
1801 * (qcow2_check_refcounts) by the time this function is called).
1803 static int check_oflag_copied(BlockDriverState
*bs
, BdrvCheckResult
*res
,
1806 BDRVQcow2State
*s
= bs
->opaque
;
1807 uint64_t *l2_table
= qemu_blockalign(bs
, s
->cluster_size
);
1813 if (fix
& BDRV_FIX_ERRORS
) {
1816 } else if (fix
& BDRV_FIX_LEAKS
) {
1817 /* Repair only if that seems safe: This function is always
1818 * called after the refcounts have been fixed, so the refcount
1819 * is accurate if that repair was successful */
1820 repair
= !res
->check_errors
&& !res
->corruptions
&& !res
->leaks
;
1825 for (i
= 0; i
< s
->l1_size
; i
++) {
1826 uint64_t l1_entry
= s
->l1_table
[i
];
1827 uint64_t l2_offset
= l1_entry
& L1E_OFFSET_MASK
;
1828 bool l2_dirty
= false;
1834 ret
= qcow2_get_refcount(bs
, l2_offset
>> s
->cluster_bits
,
1837 /* don't print message nor increment check_errors */
1840 if ((refcount
== 1) != ((l1_entry
& QCOW_OFLAG_COPIED
) != 0)) {
1841 fprintf(stderr
, "%s OFLAG_COPIED L2 cluster: l1_index=%d "
1842 "l1_entry=%" PRIx64
" refcount=%" PRIu64
"\n",
1843 repair
? "Repairing" : "ERROR", i
, l1_entry
, refcount
);
1845 s
->l1_table
[i
] = refcount
== 1
1846 ? l1_entry
| QCOW_OFLAG_COPIED
1847 : l1_entry
& ~QCOW_OFLAG_COPIED
;
1848 ret
= qcow2_write_l1_entry(bs
, i
);
1850 res
->check_errors
++;
1853 res
->corruptions_fixed
++;
1859 ret
= bdrv_pread(bs
->file
, l2_offset
, l2_table
,
1860 s
->l2_size
* sizeof(uint64_t));
1862 fprintf(stderr
, "ERROR: Could not read L2 table: %s\n",
1864 res
->check_errors
++;
1868 for (j
= 0; j
< s
->l2_size
; j
++) {
1869 uint64_t l2_entry
= be64_to_cpu(l2_table
[j
]);
1870 uint64_t data_offset
= l2_entry
& L2E_OFFSET_MASK
;
1871 QCow2ClusterType cluster_type
= qcow2_get_cluster_type(l2_entry
);
1873 if (cluster_type
== QCOW2_CLUSTER_NORMAL
||
1874 cluster_type
== QCOW2_CLUSTER_ZERO_ALLOC
) {
1875 ret
= qcow2_get_refcount(bs
,
1876 data_offset
>> s
->cluster_bits
,
1879 /* don't print message nor increment check_errors */
1882 if ((refcount
== 1) != ((l2_entry
& QCOW_OFLAG_COPIED
) != 0)) {
1883 fprintf(stderr
, "%s OFLAG_COPIED data cluster: "
1884 "l2_entry=%" PRIx64
" refcount=%" PRIu64
"\n",
1885 repair
? "Repairing" : "ERROR", l2_entry
, refcount
);
1887 l2_table
[j
] = cpu_to_be64(refcount
== 1
1888 ? l2_entry
| QCOW_OFLAG_COPIED
1889 : l2_entry
& ~QCOW_OFLAG_COPIED
);
1891 res
->corruptions_fixed
++;
1900 ret
= qcow2_pre_write_overlap_check(bs
, QCOW2_OL_ACTIVE_L2
,
1901 l2_offset
, s
->cluster_size
);
1903 fprintf(stderr
, "ERROR: Could not write L2 table; metadata "
1904 "overlap check failed: %s\n", strerror(-ret
));
1905 res
->check_errors
++;
1909 ret
= bdrv_pwrite(bs
->file
, l2_offset
, l2_table
,
1912 fprintf(stderr
, "ERROR: Could not write L2 table: %s\n",
1914 res
->check_errors
++;
1923 qemu_vfree(l2_table
);
1928 * Checks consistency of refblocks and accounts for each refblock in
1931 static int check_refblocks(BlockDriverState
*bs
, BdrvCheckResult
*res
,
1932 BdrvCheckMode fix
, bool *rebuild
,
1933 void **refcount_table
, int64_t *nb_clusters
)
1935 BDRVQcow2State
*s
= bs
->opaque
;
1939 for(i
= 0; i
< s
->refcount_table_size
; i
++) {
1940 uint64_t offset
, cluster
;
1941 offset
= s
->refcount_table
[i
];
1942 cluster
= offset
>> s
->cluster_bits
;
1944 /* Refcount blocks are cluster aligned */
1945 if (offset_into_cluster(s
, offset
)) {
1946 fprintf(stderr
, "ERROR refcount block %" PRId64
" is not "
1947 "cluster aligned; refcount table entry corrupted\n", i
);
1953 if (cluster
>= *nb_clusters
) {
1954 fprintf(stderr
, "%s refcount block %" PRId64
" is outside image\n",
1955 fix
& BDRV_FIX_ERRORS
? "Repairing" : "ERROR", i
);
1957 if (fix
& BDRV_FIX_ERRORS
) {
1958 int64_t new_nb_clusters
;
1959 Error
*local_err
= NULL
;
1961 if (offset
> INT64_MAX
- s
->cluster_size
) {
1966 ret
= bdrv_truncate(bs
->file
, offset
+ s
->cluster_size
,
1967 PREALLOC_MODE_OFF
, &local_err
);
1969 error_report_err(local_err
);
1972 size
= bdrv_getlength(bs
->file
->bs
);
1978 new_nb_clusters
= size_to_clusters(s
, size
);
1979 assert(new_nb_clusters
>= *nb_clusters
);
1981 ret
= realloc_refcount_array(s
, refcount_table
,
1982 nb_clusters
, new_nb_clusters
);
1984 res
->check_errors
++;
1988 if (cluster
>= *nb_clusters
) {
1993 res
->corruptions_fixed
++;
1994 ret
= qcow2_inc_refcounts_imrt(bs
, res
,
1995 refcount_table
, nb_clusters
,
1996 offset
, s
->cluster_size
);
2000 /* No need to check whether the refcount is now greater than 1:
2001 * This area was just allocated and zeroed, so it can only be
2002 * exactly 1 after qcow2_inc_refcounts_imrt() */
2008 fprintf(stderr
, "ERROR could not resize image: %s\n",
2017 ret
= qcow2_inc_refcounts_imrt(bs
, res
, refcount_table
, nb_clusters
,
2018 offset
, s
->cluster_size
);
2022 if (s
->get_refcount(*refcount_table
, cluster
) != 1) {
2023 fprintf(stderr
, "ERROR refcount block %" PRId64
2024 " refcount=%" PRIu64
"\n", i
,
2025 s
->get_refcount(*refcount_table
, cluster
));
2036 * Calculates an in-memory refcount table.
2038 static int calculate_refcounts(BlockDriverState
*bs
, BdrvCheckResult
*res
,
2039 BdrvCheckMode fix
, bool *rebuild
,
2040 void **refcount_table
, int64_t *nb_clusters
)
2042 BDRVQcow2State
*s
= bs
->opaque
;
2047 if (!*refcount_table
) {
2048 int64_t old_size
= 0;
2049 ret
= realloc_refcount_array(s
, refcount_table
,
2050 &old_size
, *nb_clusters
);
2052 res
->check_errors
++;
2058 ret
= qcow2_inc_refcounts_imrt(bs
, res
, refcount_table
, nb_clusters
,
2059 0, s
->cluster_size
);
2064 /* current L1 table */
2065 ret
= check_refcounts_l1(bs
, res
, refcount_table
, nb_clusters
,
2066 s
->l1_table_offset
, s
->l1_size
, CHECK_FRAG_INFO
,
2073 for (i
= 0; i
< s
->nb_snapshots
; i
++) {
2074 sn
= s
->snapshots
+ i
;
2075 if (offset_into_cluster(s
, sn
->l1_table_offset
)) {
2076 fprintf(stderr
, "ERROR snapshot %s (%s) l1_offset=%#" PRIx64
": "
2077 "L1 table is not cluster aligned; snapshot table entry "
2078 "corrupted\n", sn
->id_str
, sn
->name
, sn
->l1_table_offset
);
2082 if (sn
->l1_size
> QCOW_MAX_L1_SIZE
/ sizeof(uint64_t)) {
2083 fprintf(stderr
, "ERROR snapshot %s (%s) l1_size=%#" PRIx32
": "
2084 "L1 table is too large; snapshot table entry corrupted\n",
2085 sn
->id_str
, sn
->name
, sn
->l1_size
);
2089 ret
= check_refcounts_l1(bs
, res
, refcount_table
, nb_clusters
,
2090 sn
->l1_table_offset
, sn
->l1_size
, 0, fix
);
2095 ret
= qcow2_inc_refcounts_imrt(bs
, res
, refcount_table
, nb_clusters
,
2096 s
->snapshots_offset
, s
->snapshots_size
);
2102 ret
= qcow2_inc_refcounts_imrt(bs
, res
, refcount_table
, nb_clusters
,
2103 s
->refcount_table_offset
,
2104 s
->refcount_table_size
* sizeof(uint64_t));
2110 if (s
->crypto_header
.length
) {
2111 ret
= qcow2_inc_refcounts_imrt(bs
, res
, refcount_table
, nb_clusters
,
2112 s
->crypto_header
.offset
,
2113 s
->crypto_header
.length
);
2120 ret
= qcow2_check_bitmaps_refcounts(bs
, res
, refcount_table
, nb_clusters
);
2125 return check_refblocks(bs
, res
, fix
, rebuild
, refcount_table
, nb_clusters
);
2129 * Compares the actual reference count for each cluster in the image against the
2130 * refcount as reported by the refcount structures on-disk.
2132 static void compare_refcounts(BlockDriverState
*bs
, BdrvCheckResult
*res
,
2133 BdrvCheckMode fix
, bool *rebuild
,
2134 int64_t *highest_cluster
,
2135 void *refcount_table
, int64_t nb_clusters
)
2137 BDRVQcow2State
*s
= bs
->opaque
;
2139 uint64_t refcount1
, refcount2
;
2142 for (i
= 0, *highest_cluster
= 0; i
< nb_clusters
; i
++) {
2143 ret
= qcow2_get_refcount(bs
, i
, &refcount1
);
2145 fprintf(stderr
, "Can't get refcount for cluster %" PRId64
": %s\n",
2147 res
->check_errors
++;
2151 refcount2
= s
->get_refcount(refcount_table
, i
);
2153 if (refcount1
> 0 || refcount2
> 0) {
2154 *highest_cluster
= i
;
2157 if (refcount1
!= refcount2
) {
2158 /* Check if we're allowed to fix the mismatch */
2159 int *num_fixed
= NULL
;
2160 if (refcount1
== 0) {
2162 } else if (refcount1
> refcount2
&& (fix
& BDRV_FIX_LEAKS
)) {
2163 num_fixed
= &res
->leaks_fixed
;
2164 } else if (refcount1
< refcount2
&& (fix
& BDRV_FIX_ERRORS
)) {
2165 num_fixed
= &res
->corruptions_fixed
;
2168 fprintf(stderr
, "%s cluster %" PRId64
" refcount=%" PRIu64
2169 " reference=%" PRIu64
"\n",
2170 num_fixed
!= NULL
? "Repairing" :
2171 refcount1
< refcount2
? "ERROR" :
2173 i
, refcount1
, refcount2
);
2176 ret
= update_refcount(bs
, i
<< s
->cluster_bits
, 1,
2177 refcount_diff(refcount1
, refcount2
),
2178 refcount1
> refcount2
,
2179 QCOW2_DISCARD_ALWAYS
);
2186 /* And if we couldn't, print an error */
2187 if (refcount1
< refcount2
) {
2197 * Allocates clusters using an in-memory refcount table (IMRT) in contrast to
2198 * the on-disk refcount structures.
2200 * On input, *first_free_cluster tells where to start looking, and need not
2201 * actually be a free cluster; the returned offset will not be before that
2202 * cluster. On output, *first_free_cluster points to the first gap found, even
2203 * if that gap was too small to be used as the returned offset.
2205 * Note that *first_free_cluster is a cluster index whereas the return value is
2208 static int64_t alloc_clusters_imrt(BlockDriverState
*bs
,
2210 void **refcount_table
,
2211 int64_t *imrt_nb_clusters
,
2212 int64_t *first_free_cluster
)
2214 BDRVQcow2State
*s
= bs
->opaque
;
2215 int64_t cluster
= *first_free_cluster
, i
;
2216 bool first_gap
= true;
2217 int contiguous_free_clusters
;
2220 /* Starting at *first_free_cluster, find a range of at least cluster_count
2221 * continuously free clusters */
2222 for (contiguous_free_clusters
= 0;
2223 cluster
< *imrt_nb_clusters
&&
2224 contiguous_free_clusters
< cluster_count
;
2227 if (!s
->get_refcount(*refcount_table
, cluster
)) {
2228 contiguous_free_clusters
++;
2230 /* If this is the first free cluster found, update
2231 * *first_free_cluster accordingly */
2232 *first_free_cluster
= cluster
;
2235 } else if (contiguous_free_clusters
) {
2236 contiguous_free_clusters
= 0;
2240 /* If contiguous_free_clusters is greater than zero, it contains the number
2241 * of continuously free clusters until the current cluster; the first free
2242 * cluster in the current "gap" is therefore
2243 * cluster - contiguous_free_clusters */
2245 /* If no such range could be found, grow the in-memory refcount table
2246 * accordingly to append free clusters at the end of the image */
2247 if (contiguous_free_clusters
< cluster_count
) {
2248 /* contiguous_free_clusters clusters are already empty at the image end;
2249 * we need cluster_count clusters; therefore, we have to allocate
2250 * cluster_count - contiguous_free_clusters new clusters at the end of
2251 * the image (which is the current value of cluster; note that cluster
2252 * may exceed old_imrt_nb_clusters if *first_free_cluster pointed beyond
2254 ret
= realloc_refcount_array(s
, refcount_table
, imrt_nb_clusters
,
2255 cluster
+ cluster_count
2256 - contiguous_free_clusters
);
2262 /* Go back to the first free cluster */
2263 cluster
-= contiguous_free_clusters
;
2264 for (i
= 0; i
< cluster_count
; i
++) {
2265 s
->set_refcount(*refcount_table
, cluster
+ i
, 1);
2268 return cluster
<< s
->cluster_bits
;
2272 * Creates a new refcount structure based solely on the in-memory information
2273 * given through *refcount_table. All necessary allocations will be reflected
2276 * On success, the old refcount structure is leaked (it will be covered by the
2277 * new refcount structure).
2279 static int rebuild_refcount_structure(BlockDriverState
*bs
,
2280 BdrvCheckResult
*res
,
2281 void **refcount_table
,
2282 int64_t *nb_clusters
)
2284 BDRVQcow2State
*s
= bs
->opaque
;
2285 int64_t first_free_cluster
= 0, reftable_offset
= -1, cluster
= 0;
2286 int64_t refblock_offset
, refblock_start
, refblock_index
;
2287 uint32_t reftable_size
= 0;
2288 uint64_t *on_disk_reftable
= NULL
;
2289 void *on_disk_refblock
;
2292 uint64_t reftable_offset
;
2293 uint32_t reftable_clusters
;
2294 } QEMU_PACKED reftable_offset_and_clusters
;
2296 qcow2_cache_empty(bs
, s
->refcount_block_cache
);
2299 for (; cluster
< *nb_clusters
; cluster
++) {
2300 if (!s
->get_refcount(*refcount_table
, cluster
)) {
2304 refblock_index
= cluster
>> s
->refcount_block_bits
;
2305 refblock_start
= refblock_index
<< s
->refcount_block_bits
;
2307 /* Don't allocate a cluster in a refblock already written to disk */
2308 if (first_free_cluster
< refblock_start
) {
2309 first_free_cluster
= refblock_start
;
2311 refblock_offset
= alloc_clusters_imrt(bs
, 1, refcount_table
,
2312 nb_clusters
, &first_free_cluster
);
2313 if (refblock_offset
< 0) {
2314 fprintf(stderr
, "ERROR allocating refblock: %s\n",
2315 strerror(-refblock_offset
));
2316 res
->check_errors
++;
2317 ret
= refblock_offset
;
2321 if (reftable_size
<= refblock_index
) {
2322 uint32_t old_reftable_size
= reftable_size
;
2323 uint64_t *new_on_disk_reftable
;
2325 reftable_size
= ROUND_UP((refblock_index
+ 1) * sizeof(uint64_t),
2326 s
->cluster_size
) / sizeof(uint64_t);
2327 new_on_disk_reftable
= g_try_realloc(on_disk_reftable
,
2330 if (!new_on_disk_reftable
) {
2331 res
->check_errors
++;
2335 on_disk_reftable
= new_on_disk_reftable
;
2337 memset(on_disk_reftable
+ old_reftable_size
, 0,
2338 (reftable_size
- old_reftable_size
) * sizeof(uint64_t));
2340 /* The offset we have for the reftable is now no longer valid;
2341 * this will leak that range, but we can easily fix that by running
2342 * a leak-fixing check after this rebuild operation */
2343 reftable_offset
= -1;
2345 assert(on_disk_reftable
);
2347 on_disk_reftable
[refblock_index
] = refblock_offset
;
2349 /* If this is apparently the last refblock (for now), try to squeeze the
2351 if (refblock_index
== (*nb_clusters
- 1) >> s
->refcount_block_bits
&&
2352 reftable_offset
< 0)
2354 uint64_t reftable_clusters
= size_to_clusters(s
, reftable_size
*
2356 reftable_offset
= alloc_clusters_imrt(bs
, reftable_clusters
,
2357 refcount_table
, nb_clusters
,
2358 &first_free_cluster
);
2359 if (reftable_offset
< 0) {
2360 fprintf(stderr
, "ERROR allocating reftable: %s\n",
2361 strerror(-reftable_offset
));
2362 res
->check_errors
++;
2363 ret
= reftable_offset
;
2368 ret
= qcow2_pre_write_overlap_check(bs
, 0, refblock_offset
,
2371 fprintf(stderr
, "ERROR writing refblock: %s\n", strerror(-ret
));
2375 /* The size of *refcount_table is always cluster-aligned, therefore the
2376 * write operation will not overflow */
2377 on_disk_refblock
= (void *)((char *) *refcount_table
+
2378 refblock_index
* s
->cluster_size
);
2380 ret
= bdrv_write(bs
->file
, refblock_offset
/ BDRV_SECTOR_SIZE
,
2381 on_disk_refblock
, s
->cluster_sectors
);
2383 fprintf(stderr
, "ERROR writing refblock: %s\n", strerror(-ret
));
2387 /* Go to the end of this refblock */
2388 cluster
= refblock_start
+ s
->refcount_block_size
- 1;
2391 if (reftable_offset
< 0) {
2392 uint64_t post_refblock_start
, reftable_clusters
;
2394 post_refblock_start
= ROUND_UP(*nb_clusters
, s
->refcount_block_size
);
2395 reftable_clusters
= size_to_clusters(s
,
2396 reftable_size
* sizeof(uint64_t));
2397 /* Not pretty but simple */
2398 if (first_free_cluster
< post_refblock_start
) {
2399 first_free_cluster
= post_refblock_start
;
2401 reftable_offset
= alloc_clusters_imrt(bs
, reftable_clusters
,
2402 refcount_table
, nb_clusters
,
2403 &first_free_cluster
);
2404 if (reftable_offset
< 0) {
2405 fprintf(stderr
, "ERROR allocating reftable: %s\n",
2406 strerror(-reftable_offset
));
2407 res
->check_errors
++;
2408 ret
= reftable_offset
;
2412 goto write_refblocks
;
2415 for (refblock_index
= 0; refblock_index
< reftable_size
; refblock_index
++) {
2416 cpu_to_be64s(&on_disk_reftable
[refblock_index
]);
2419 ret
= qcow2_pre_write_overlap_check(bs
, 0, reftable_offset
,
2420 reftable_size
* sizeof(uint64_t));
2422 fprintf(stderr
, "ERROR writing reftable: %s\n", strerror(-ret
));
2426 assert(reftable_size
< INT_MAX
/ sizeof(uint64_t));
2427 ret
= bdrv_pwrite(bs
->file
, reftable_offset
, on_disk_reftable
,
2428 reftable_size
* sizeof(uint64_t));
2430 fprintf(stderr
, "ERROR writing reftable: %s\n", strerror(-ret
));
2434 /* Enter new reftable into the image header */
2435 reftable_offset_and_clusters
.reftable_offset
= cpu_to_be64(reftable_offset
);
2436 reftable_offset_and_clusters
.reftable_clusters
=
2437 cpu_to_be32(size_to_clusters(s
, reftable_size
* sizeof(uint64_t)));
2438 ret
= bdrv_pwrite_sync(bs
->file
,
2439 offsetof(QCowHeader
, refcount_table_offset
),
2440 &reftable_offset_and_clusters
,
2441 sizeof(reftable_offset_and_clusters
));
2443 fprintf(stderr
, "ERROR setting reftable: %s\n", strerror(-ret
));
2447 for (refblock_index
= 0; refblock_index
< reftable_size
; refblock_index
++) {
2448 be64_to_cpus(&on_disk_reftable
[refblock_index
]);
2450 s
->refcount_table
= on_disk_reftable
;
2451 s
->refcount_table_offset
= reftable_offset
;
2452 s
->refcount_table_size
= reftable_size
;
2453 update_max_refcount_table_index(s
);
2458 g_free(on_disk_reftable
);
2463 * Checks an image for refcount consistency.
2465 * Returns 0 if no errors are found, the number of errors in case the image is
2466 * detected as corrupted, and -errno when an internal error occurred.
2468 int qcow2_check_refcounts(BlockDriverState
*bs
, BdrvCheckResult
*res
,
2471 BDRVQcow2State
*s
= bs
->opaque
;
2472 BdrvCheckResult pre_compare_res
;
2473 int64_t size
, highest_cluster
, nb_clusters
;
2474 void *refcount_table
= NULL
;
2475 bool rebuild
= false;
2478 size
= bdrv_getlength(bs
->file
->bs
);
2480 res
->check_errors
++;
2484 nb_clusters
= size_to_clusters(s
, size
);
2485 if (nb_clusters
> INT_MAX
) {
2486 res
->check_errors
++;
2490 res
->bfi
.total_clusters
=
2491 size_to_clusters(s
, bs
->total_sectors
* BDRV_SECTOR_SIZE
);
2493 ret
= calculate_refcounts(bs
, res
, fix
, &rebuild
, &refcount_table
,
2499 /* In case we don't need to rebuild the refcount structure (but want to fix
2500 * something), this function is immediately called again, in which case the
2501 * result should be ignored */
2502 pre_compare_res
= *res
;
2503 compare_refcounts(bs
, res
, 0, &rebuild
, &highest_cluster
, refcount_table
,
2506 if (rebuild
&& (fix
& BDRV_FIX_ERRORS
)) {
2507 BdrvCheckResult old_res
= *res
;
2508 int fresh_leaks
= 0;
2510 fprintf(stderr
, "Rebuilding refcount structure\n");
2511 ret
= rebuild_refcount_structure(bs
, res
, &refcount_table
,
2517 res
->corruptions
= 0;
2520 /* Because the old reftable has been exchanged for a new one the
2521 * references have to be recalculated */
2523 memset(refcount_table
, 0, refcount_array_byte_size(s
, nb_clusters
));
2524 ret
= calculate_refcounts(bs
, res
, 0, &rebuild
, &refcount_table
,
2530 if (fix
& BDRV_FIX_LEAKS
) {
2531 /* The old refcount structures are now leaked, fix it; the result
2532 * can be ignored, aside from leaks which were introduced by
2533 * rebuild_refcount_structure() that could not be fixed */
2534 BdrvCheckResult saved_res
= *res
;
2535 *res
= (BdrvCheckResult
){ 0 };
2537 compare_refcounts(bs
, res
, BDRV_FIX_LEAKS
, &rebuild
,
2538 &highest_cluster
, refcount_table
, nb_clusters
);
2540 fprintf(stderr
, "ERROR rebuilt refcount structure is still "
2544 /* Any leaks accounted for here were introduced by
2545 * rebuild_refcount_structure() because that function has created a
2546 * new refcount structure from scratch */
2547 fresh_leaks
= res
->leaks
;
2551 if (res
->corruptions
< old_res
.corruptions
) {
2552 res
->corruptions_fixed
+= old_res
.corruptions
- res
->corruptions
;
2554 if (res
->leaks
< old_res
.leaks
) {
2555 res
->leaks_fixed
+= old_res
.leaks
- res
->leaks
;
2557 res
->leaks
+= fresh_leaks
;
2560 fprintf(stderr
, "ERROR need to rebuild refcount structures\n");
2561 res
->check_errors
++;
2566 if (res
->leaks
|| res
->corruptions
) {
2567 *res
= pre_compare_res
;
2568 compare_refcounts(bs
, res
, fix
, &rebuild
, &highest_cluster
,
2569 refcount_table
, nb_clusters
);
2573 /* check OFLAG_COPIED */
2574 ret
= check_oflag_copied(bs
, res
, fix
);
2579 res
->image_end_offset
= (highest_cluster
+ 1) * s
->cluster_size
;
2583 g_free(refcount_table
);
2588 #define overlaps_with(ofs, sz) \
2589 ranges_overlap(offset, size, ofs, sz)
2592 * Checks if the given offset into the image file is actually free to use by
2593 * looking for overlaps with important metadata sections (L1/L2 tables etc.),
2594 * i.e. a sanity check without relying on the refcount tables.
2596 * The ign parameter specifies what checks not to perform (being a bitmask of
2597 * QCow2MetadataOverlap values), i.e., what sections to ignore.
2600 * - 0 if writing to this offset will not affect the mentioned metadata
2601 * - a positive QCow2MetadataOverlap value indicating one overlapping section
2602 * - a negative value (-errno) indicating an error while performing a check,
2603 * e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2
2605 int qcow2_check_metadata_overlap(BlockDriverState
*bs
, int ign
, int64_t offset
,
2608 BDRVQcow2State
*s
= bs
->opaque
;
2609 int chk
= s
->overlap_check
& ~ign
;
2616 if (chk
& QCOW2_OL_MAIN_HEADER
) {
2617 if (offset
< s
->cluster_size
) {
2618 return QCOW2_OL_MAIN_HEADER
;
2622 /* align range to test to cluster boundaries */
2623 size
= ROUND_UP(offset_into_cluster(s
, offset
) + size
, s
->cluster_size
);
2624 offset
= start_of_cluster(s
, offset
);
2626 if ((chk
& QCOW2_OL_ACTIVE_L1
) && s
->l1_size
) {
2627 if (overlaps_with(s
->l1_table_offset
, s
->l1_size
* sizeof(uint64_t))) {
2628 return QCOW2_OL_ACTIVE_L1
;
2632 if ((chk
& QCOW2_OL_REFCOUNT_TABLE
) && s
->refcount_table_size
) {
2633 if (overlaps_with(s
->refcount_table_offset
,
2634 s
->refcount_table_size
* sizeof(uint64_t))) {
2635 return QCOW2_OL_REFCOUNT_TABLE
;
2639 if ((chk
& QCOW2_OL_SNAPSHOT_TABLE
) && s
->snapshots_size
) {
2640 if (overlaps_with(s
->snapshots_offset
, s
->snapshots_size
)) {
2641 return QCOW2_OL_SNAPSHOT_TABLE
;
2645 if ((chk
& QCOW2_OL_INACTIVE_L1
) && s
->snapshots
) {
2646 for (i
= 0; i
< s
->nb_snapshots
; i
++) {
2647 if (s
->snapshots
[i
].l1_size
&&
2648 overlaps_with(s
->snapshots
[i
].l1_table_offset
,
2649 s
->snapshots
[i
].l1_size
* sizeof(uint64_t))) {
2650 return QCOW2_OL_INACTIVE_L1
;
2655 if ((chk
& QCOW2_OL_ACTIVE_L2
) && s
->l1_table
) {
2656 for (i
= 0; i
< s
->l1_size
; i
++) {
2657 if ((s
->l1_table
[i
] & L1E_OFFSET_MASK
) &&
2658 overlaps_with(s
->l1_table
[i
] & L1E_OFFSET_MASK
,
2660 return QCOW2_OL_ACTIVE_L2
;
2665 if ((chk
& QCOW2_OL_REFCOUNT_BLOCK
) && s
->refcount_table
) {
2666 unsigned last_entry
= s
->max_refcount_table_index
;
2667 assert(last_entry
< s
->refcount_table_size
);
2668 assert(last_entry
+ 1 == s
->refcount_table_size
||
2669 (s
->refcount_table
[last_entry
+ 1] & REFT_OFFSET_MASK
) == 0);
2670 for (i
= 0; i
<= last_entry
; i
++) {
2671 if ((s
->refcount_table
[i
] & REFT_OFFSET_MASK
) &&
2672 overlaps_with(s
->refcount_table
[i
] & REFT_OFFSET_MASK
,
2674 return QCOW2_OL_REFCOUNT_BLOCK
;
2679 if ((chk
& QCOW2_OL_INACTIVE_L2
) && s
->snapshots
) {
2680 for (i
= 0; i
< s
->nb_snapshots
; i
++) {
2681 uint64_t l1_ofs
= s
->snapshots
[i
].l1_table_offset
;
2682 uint32_t l1_sz
= s
->snapshots
[i
].l1_size
;
2683 uint64_t l1_sz2
= l1_sz
* sizeof(uint64_t);
2687 ret
= qcow2_validate_table(bs
, l1_ofs
, l1_sz
, sizeof(uint64_t),
2688 QCOW_MAX_L1_SIZE
, "", NULL
);
2693 l1
= g_try_malloc(l1_sz2
);
2695 if (l1_sz2
&& l1
== NULL
) {
2699 ret
= bdrv_pread(bs
->file
, l1_ofs
, l1
, l1_sz2
);
2705 for (j
= 0; j
< l1_sz
; j
++) {
2706 uint64_t l2_ofs
= be64_to_cpu(l1
[j
]) & L1E_OFFSET_MASK
;
2707 if (l2_ofs
&& overlaps_with(l2_ofs
, s
->cluster_size
)) {
2709 return QCOW2_OL_INACTIVE_L2
;
2717 if ((chk
& QCOW2_OL_BITMAP_DIRECTORY
) &&
2718 (s
->autoclear_features
& QCOW2_AUTOCLEAR_BITMAPS
))
2720 if (overlaps_with(s
->bitmap_directory_offset
,
2721 s
->bitmap_directory_size
))
2723 return QCOW2_OL_BITMAP_DIRECTORY
;
2730 static const char *metadata_ol_names
[] = {
2731 [QCOW2_OL_MAIN_HEADER_BITNR
] = "qcow2_header",
2732 [QCOW2_OL_ACTIVE_L1_BITNR
] = "active L1 table",
2733 [QCOW2_OL_ACTIVE_L2_BITNR
] = "active L2 table",
2734 [QCOW2_OL_REFCOUNT_TABLE_BITNR
] = "refcount table",
2735 [QCOW2_OL_REFCOUNT_BLOCK_BITNR
] = "refcount block",
2736 [QCOW2_OL_SNAPSHOT_TABLE_BITNR
] = "snapshot table",
2737 [QCOW2_OL_INACTIVE_L1_BITNR
] = "inactive L1 table",
2738 [QCOW2_OL_INACTIVE_L2_BITNR
] = "inactive L2 table",
2739 [QCOW2_OL_BITMAP_DIRECTORY_BITNR
] = "bitmap directory",
2741 QEMU_BUILD_BUG_ON(QCOW2_OL_MAX_BITNR
!= ARRAY_SIZE(metadata_ol_names
));
2744 * First performs a check for metadata overlaps (through
2745 * qcow2_check_metadata_overlap); if that fails with a negative value (error
2746 * while performing a check), that value is returned. If an impending overlap
2747 * is detected, the BDS will be made unusable, the qcow2 file marked corrupt
2748 * and -EIO returned.
2750 * Returns 0 if there were neither overlaps nor errors while checking for
2751 * overlaps; or a negative value (-errno) on error.
2753 int qcow2_pre_write_overlap_check(BlockDriverState
*bs
, int ign
, int64_t offset
,
2756 int ret
= qcow2_check_metadata_overlap(bs
, ign
, offset
, size
);
2760 } else if (ret
> 0) {
2761 int metadata_ol_bitnr
= ctz32(ret
);
2762 assert(metadata_ol_bitnr
< QCOW2_OL_MAX_BITNR
);
2764 qcow2_signal_corruption(bs
, true, offset
, size
, "Preventing invalid "
2765 "write on metadata (overlaps with %s)",
2766 metadata_ol_names
[metadata_ol_bitnr
]);
2773 /* A pointer to a function of this type is given to walk_over_reftable(). That
2774 * function will create refblocks and pass them to a RefblockFinishOp once they
2775 * are completed (@refblock). @refblock_empty is set if the refblock is
2778 * Along with the refblock, a corresponding reftable entry is passed, in the
2779 * reftable @reftable (which may be reallocated) at @reftable_index.
2781 * @allocated should be set to true if a new cluster has been allocated.
2783 typedef int (RefblockFinishOp
)(BlockDriverState
*bs
, uint64_t **reftable
,
2784 uint64_t reftable_index
, uint64_t *reftable_size
,
2785 void *refblock
, bool refblock_empty
,
2786 bool *allocated
, Error
**errp
);
2789 * This "operation" for walk_over_reftable() allocates the refblock on disk (if
2790 * it is not empty) and inserts its offset into the new reftable. The size of
2791 * this new reftable is increased as required.
2793 static int alloc_refblock(BlockDriverState
*bs
, uint64_t **reftable
,
2794 uint64_t reftable_index
, uint64_t *reftable_size
,
2795 void *refblock
, bool refblock_empty
, bool *allocated
,
2798 BDRVQcow2State
*s
= bs
->opaque
;
2801 if (!refblock_empty
&& reftable_index
>= *reftable_size
) {
2802 uint64_t *new_reftable
;
2803 uint64_t new_reftable_size
;
2805 new_reftable_size
= ROUND_UP(reftable_index
+ 1,
2806 s
->cluster_size
/ sizeof(uint64_t));
2807 if (new_reftable_size
> QCOW_MAX_REFTABLE_SIZE
/ sizeof(uint64_t)) {
2809 "This operation would make the refcount table grow "
2810 "beyond the maximum size supported by QEMU, aborting");
2814 new_reftable
= g_try_realloc(*reftable
, new_reftable_size
*
2816 if (!new_reftable
) {
2817 error_setg(errp
, "Failed to increase reftable buffer size");
2821 memset(new_reftable
+ *reftable_size
, 0,
2822 (new_reftable_size
- *reftable_size
) * sizeof(uint64_t));
2824 *reftable
= new_reftable
;
2825 *reftable_size
= new_reftable_size
;
2828 if (!refblock_empty
&& !(*reftable
)[reftable_index
]) {
2829 offset
= qcow2_alloc_clusters(bs
, s
->cluster_size
);
2831 error_setg_errno(errp
, -offset
, "Failed to allocate refblock");
2834 (*reftable
)[reftable_index
] = offset
;
2842 * This "operation" for walk_over_reftable() writes the refblock to disk at the
2843 * offset specified by the new reftable's entry. It does not modify the new
2844 * reftable or change any refcounts.
2846 static int flush_refblock(BlockDriverState
*bs
, uint64_t **reftable
,
2847 uint64_t reftable_index
, uint64_t *reftable_size
,
2848 void *refblock
, bool refblock_empty
, bool *allocated
,
2851 BDRVQcow2State
*s
= bs
->opaque
;
2855 if (reftable_index
< *reftable_size
&& (*reftable
)[reftable_index
]) {
2856 offset
= (*reftable
)[reftable_index
];
2858 ret
= qcow2_pre_write_overlap_check(bs
, 0, offset
, s
->cluster_size
);
2860 error_setg_errno(errp
, -ret
, "Overlap check failed");
2864 ret
= bdrv_pwrite(bs
->file
, offset
, refblock
, s
->cluster_size
);
2866 error_setg_errno(errp
, -ret
, "Failed to write refblock");
2870 assert(refblock_empty
);
2877 * This function walks over the existing reftable and every referenced refblock;
2878 * if @new_set_refcount is non-NULL, it is called for every refcount entry to
2879 * create an equal new entry in the passed @new_refblock. Once that
2880 * @new_refblock is completely filled, @operation will be called.
2882 * @status_cb and @cb_opaque are used for the amend operation's status callback.
2883 * @index is the index of the walk_over_reftable() calls and @total is the total
2884 * number of walk_over_reftable() calls per amend operation. Both are used for
2885 * calculating the parameters for the status callback.
2887 * @allocated is set to true if a new cluster has been allocated.
2889 static int walk_over_reftable(BlockDriverState
*bs
, uint64_t **new_reftable
,
2890 uint64_t *new_reftable_index
,
2891 uint64_t *new_reftable_size
,
2892 void *new_refblock
, int new_refblock_size
,
2893 int new_refcount_bits
,
2894 RefblockFinishOp
*operation
, bool *allocated
,
2895 Qcow2SetRefcountFunc
*new_set_refcount
,
2896 BlockDriverAmendStatusCB
*status_cb
,
2897 void *cb_opaque
, int index
, int total
,
2900 BDRVQcow2State
*s
= bs
->opaque
;
2901 uint64_t reftable_index
;
2902 bool new_refblock_empty
= true;
2904 int new_refblock_index
= 0;
2907 for (reftable_index
= 0; reftable_index
< s
->refcount_table_size
;
2910 uint64_t refblock_offset
= s
->refcount_table
[reftable_index
]
2913 status_cb(bs
, (uint64_t)index
* s
->refcount_table_size
+ reftable_index
,
2914 (uint64_t)total
* s
->refcount_table_size
, cb_opaque
);
2916 if (refblock_offset
) {
2919 if (offset_into_cluster(s
, refblock_offset
)) {
2920 qcow2_signal_corruption(bs
, true, -1, -1, "Refblock offset %#"
2921 PRIx64
" unaligned (reftable index: %#"
2922 PRIx64
")", refblock_offset
,
2925 "Image is corrupt (unaligned refblock offset)");
2929 ret
= qcow2_cache_get(bs
, s
->refcount_block_cache
, refblock_offset
,
2932 error_setg_errno(errp
, -ret
, "Failed to retrieve refblock");
2936 for (refblock_index
= 0; refblock_index
< s
->refcount_block_size
;
2941 if (new_refblock_index
>= new_refblock_size
) {
2942 /* new_refblock is now complete */
2943 ret
= operation(bs
, new_reftable
, *new_reftable_index
,
2944 new_reftable_size
, new_refblock
,
2945 new_refblock_empty
, allocated
, errp
);
2947 qcow2_cache_put(s
->refcount_block_cache
, &refblock
);
2951 (*new_reftable_index
)++;
2952 new_refblock_index
= 0;
2953 new_refblock_empty
= true;
2956 refcount
= s
->get_refcount(refblock
, refblock_index
);
2957 if (new_refcount_bits
< 64 && refcount
>> new_refcount_bits
) {
2960 qcow2_cache_put(s
->refcount_block_cache
, &refblock
);
2962 offset
= ((reftable_index
<< s
->refcount_block_bits
)
2963 + refblock_index
) << s
->cluster_bits
;
2965 error_setg(errp
, "Cannot decrease refcount entry width to "
2966 "%i bits: Cluster at offset %#" PRIx64
" has a "
2967 "refcount of %" PRIu64
, new_refcount_bits
,
2972 if (new_set_refcount
) {
2973 new_set_refcount(new_refblock
, new_refblock_index
++,
2976 new_refblock_index
++;
2978 new_refblock_empty
= new_refblock_empty
&& refcount
== 0;
2981 qcow2_cache_put(s
->refcount_block_cache
, &refblock
);
2983 /* No refblock means every refcount is 0 */
2984 for (refblock_index
= 0; refblock_index
< s
->refcount_block_size
;
2987 if (new_refblock_index
>= new_refblock_size
) {
2988 /* new_refblock is now complete */
2989 ret
= operation(bs
, new_reftable
, *new_reftable_index
,
2990 new_reftable_size
, new_refblock
,
2991 new_refblock_empty
, allocated
, errp
);
2996 (*new_reftable_index
)++;
2997 new_refblock_index
= 0;
2998 new_refblock_empty
= true;
3001 if (new_set_refcount
) {
3002 new_set_refcount(new_refblock
, new_refblock_index
++, 0);
3004 new_refblock_index
++;
3010 if (new_refblock_index
> 0) {
3011 /* Complete the potentially existing partially filled final refblock */
3012 if (new_set_refcount
) {
3013 for (; new_refblock_index
< new_refblock_size
;
3014 new_refblock_index
++)
3016 new_set_refcount(new_refblock
, new_refblock_index
, 0);
3020 ret
= operation(bs
, new_reftable
, *new_reftable_index
,
3021 new_reftable_size
, new_refblock
, new_refblock_empty
,
3027 (*new_reftable_index
)++;
3030 status_cb(bs
, (uint64_t)(index
+ 1) * s
->refcount_table_size
,
3031 (uint64_t)total
* s
->refcount_table_size
, cb_opaque
);
3036 int qcow2_change_refcount_order(BlockDriverState
*bs
, int refcount_order
,
3037 BlockDriverAmendStatusCB
*status_cb
,
3038 void *cb_opaque
, Error
**errp
)
3040 BDRVQcow2State
*s
= bs
->opaque
;
3041 Qcow2GetRefcountFunc
*new_get_refcount
;
3042 Qcow2SetRefcountFunc
*new_set_refcount
;
3043 void *new_refblock
= qemu_blockalign(bs
->file
->bs
, s
->cluster_size
);
3044 uint64_t *new_reftable
= NULL
, new_reftable_size
= 0;
3045 uint64_t *old_reftable
, old_reftable_size
, old_reftable_offset
;
3046 uint64_t new_reftable_index
= 0;
3048 int64_t new_reftable_offset
= 0, allocated_reftable_size
= 0;
3049 int new_refblock_size
, new_refcount_bits
= 1 << refcount_order
;
3050 int old_refcount_order
;
3053 bool new_allocation
;
3055 assert(s
->qcow_version
>= 3);
3056 assert(refcount_order
>= 0 && refcount_order
<= 6);
3058 /* see qcow2_open() */
3059 new_refblock_size
= 1 << (s
->cluster_bits
- (refcount_order
- 3));
3061 new_get_refcount
= get_refcount_funcs
[refcount_order
];
3062 new_set_refcount
= set_refcount_funcs
[refcount_order
];
3068 new_allocation
= false;
3070 /* At least we have to do this walk and the one which writes the
3071 * refblocks; also, at least we have to do this loop here at least
3072 * twice (normally), first to do the allocations, and second to
3073 * determine that everything is correctly allocated, this then makes
3074 * three walks in total */
3075 total_walks
= MAX(walk_index
+ 2, 3);
3077 /* First, allocate the structures so they are present in the refcount
3079 ret
= walk_over_reftable(bs
, &new_reftable
, &new_reftable_index
,
3080 &new_reftable_size
, NULL
, new_refblock_size
,
3081 new_refcount_bits
, &alloc_refblock
,
3082 &new_allocation
, NULL
, status_cb
, cb_opaque
,
3083 walk_index
++, total_walks
, errp
);
3088 new_reftable_index
= 0;
3090 if (new_allocation
) {
3091 if (new_reftable_offset
) {
3092 qcow2_free_clusters(bs
, new_reftable_offset
,
3093 allocated_reftable_size
* sizeof(uint64_t),
3094 QCOW2_DISCARD_NEVER
);
3097 new_reftable_offset
= qcow2_alloc_clusters(bs
, new_reftable_size
*
3099 if (new_reftable_offset
< 0) {
3100 error_setg_errno(errp
, -new_reftable_offset
,
3101 "Failed to allocate the new reftable");
3102 ret
= new_reftable_offset
;
3105 allocated_reftable_size
= new_reftable_size
;
3107 } while (new_allocation
);
3109 /* Second, write the new refblocks */
3110 ret
= walk_over_reftable(bs
, &new_reftable
, &new_reftable_index
,
3111 &new_reftable_size
, new_refblock
,
3112 new_refblock_size
, new_refcount_bits
,
3113 &flush_refblock
, &new_allocation
, new_set_refcount
,
3114 status_cb
, cb_opaque
, walk_index
, walk_index
+ 1,
3119 assert(!new_allocation
);
3122 /* Write the new reftable */
3123 ret
= qcow2_pre_write_overlap_check(bs
, 0, new_reftable_offset
,
3124 new_reftable_size
* sizeof(uint64_t));
3126 error_setg_errno(errp
, -ret
, "Overlap check failed");
3130 for (i
= 0; i
< new_reftable_size
; i
++) {
3131 cpu_to_be64s(&new_reftable
[i
]);
3134 ret
= bdrv_pwrite(bs
->file
, new_reftable_offset
, new_reftable
,
3135 new_reftable_size
* sizeof(uint64_t));
3137 for (i
= 0; i
< new_reftable_size
; i
++) {
3138 be64_to_cpus(&new_reftable
[i
]);
3142 error_setg_errno(errp
, -ret
, "Failed to write the new reftable");
3147 /* Empty the refcount cache */
3148 ret
= qcow2_cache_flush(bs
, s
->refcount_block_cache
);
3150 error_setg_errno(errp
, -ret
, "Failed to flush the refblock cache");
3154 /* Update the image header to point to the new reftable; this only updates
3155 * the fields which are relevant to qcow2_update_header(); other fields
3156 * such as s->refcount_table or s->refcount_bits stay stale for now
3157 * (because we have to restore everything if qcow2_update_header() fails) */
3158 old_refcount_order
= s
->refcount_order
;
3159 old_reftable_size
= s
->refcount_table_size
;
3160 old_reftable_offset
= s
->refcount_table_offset
;
3162 s
->refcount_order
= refcount_order
;
3163 s
->refcount_table_size
= new_reftable_size
;
3164 s
->refcount_table_offset
= new_reftable_offset
;
3166 ret
= qcow2_update_header(bs
);
3168 s
->refcount_order
= old_refcount_order
;
3169 s
->refcount_table_size
= old_reftable_size
;
3170 s
->refcount_table_offset
= old_reftable_offset
;
3171 error_setg_errno(errp
, -ret
, "Failed to update the qcow2 header");
3175 /* Now update the rest of the in-memory information */
3176 old_reftable
= s
->refcount_table
;
3177 s
->refcount_table
= new_reftable
;
3178 update_max_refcount_table_index(s
);
3180 s
->refcount_bits
= 1 << refcount_order
;
3181 s
->refcount_max
= UINT64_C(1) << (s
->refcount_bits
- 1);
3182 s
->refcount_max
+= s
->refcount_max
- 1;
3184 s
->refcount_block_bits
= s
->cluster_bits
- (refcount_order
- 3);
3185 s
->refcount_block_size
= 1 << s
->refcount_block_bits
;
3187 s
->get_refcount
= new_get_refcount
;
3188 s
->set_refcount
= new_set_refcount
;
3190 /* For cleaning up all old refblocks and the old reftable below the "done"
3192 new_reftable
= old_reftable
;
3193 new_reftable_size
= old_reftable_size
;
3194 new_reftable_offset
= old_reftable_offset
;
3198 /* On success, new_reftable actually points to the old reftable (and
3199 * new_reftable_size is the old reftable's size); but that is just
3201 for (i
= 0; i
< new_reftable_size
; i
++) {
3202 uint64_t offset
= new_reftable
[i
] & REFT_OFFSET_MASK
;
3204 qcow2_free_clusters(bs
, offset
, s
->cluster_size
,
3205 QCOW2_DISCARD_OTHER
);
3208 g_free(new_reftable
);
3210 if (new_reftable_offset
> 0) {
3211 qcow2_free_clusters(bs
, new_reftable_offset
,
3212 new_reftable_size
* sizeof(uint64_t),
3213 QCOW2_DISCARD_OTHER
);
3217 qemu_vfree(new_refblock
);
3221 static int64_t get_refblock_offset(BlockDriverState
*bs
, uint64_t offset
)
3223 BDRVQcow2State
*s
= bs
->opaque
;
3224 uint32_t index
= offset_to_reftable_index(s
, offset
);
3225 int64_t covering_refblock_offset
= 0;
3227 if (index
< s
->refcount_table_size
) {
3228 covering_refblock_offset
= s
->refcount_table
[index
] & REFT_OFFSET_MASK
;
3230 if (!covering_refblock_offset
) {
3231 qcow2_signal_corruption(bs
, true, -1, -1, "Refblock at %#" PRIx64
" is "
3232 "not covered by the refcount structures",
3237 return covering_refblock_offset
;
3240 static int qcow2_discard_refcount_block(BlockDriverState
*bs
,
3241 uint64_t discard_block_offs
)
3243 BDRVQcow2State
*s
= bs
->opaque
;
3244 int64_t refblock_offs
;
3245 uint64_t cluster_index
= discard_block_offs
>> s
->cluster_bits
;
3246 uint32_t block_index
= cluster_index
& (s
->refcount_block_size
- 1);
3250 refblock_offs
= get_refblock_offset(bs
, discard_block_offs
);
3251 if (refblock_offs
< 0) {
3252 return refblock_offs
;
3255 assert(discard_block_offs
!= 0);
3257 ret
= qcow2_cache_get(bs
, s
->refcount_block_cache
, refblock_offs
,
3263 if (s
->get_refcount(refblock
, block_index
) != 1) {
3264 qcow2_signal_corruption(bs
, true, -1, -1, "Invalid refcount:"
3265 " refblock offset %#" PRIx64
3266 ", reftable index %u"
3267 ", block offset %#" PRIx64
3268 ", refcount %#" PRIx64
,
3270 offset_to_reftable_index(s
, discard_block_offs
),
3272 s
->get_refcount(refblock
, block_index
));
3273 qcow2_cache_put(s
->refcount_block_cache
, &refblock
);
3276 s
->set_refcount(refblock
, block_index
, 0);
3278 qcow2_cache_entry_mark_dirty(s
->refcount_block_cache
, refblock
);
3280 qcow2_cache_put(s
->refcount_block_cache
, &refblock
);
3282 if (cluster_index
< s
->free_cluster_index
) {
3283 s
->free_cluster_index
= cluster_index
;
3286 refblock
= qcow2_cache_is_table_offset(s
->refcount_block_cache
,
3287 discard_block_offs
);
3289 /* discard refblock from the cache if refblock is cached */
3290 qcow2_cache_discard(s
->refcount_block_cache
, refblock
);
3292 update_refcount_discard(bs
, discard_block_offs
, s
->cluster_size
);
3297 int qcow2_shrink_reftable(BlockDriverState
*bs
)
3299 BDRVQcow2State
*s
= bs
->opaque
;
3300 uint64_t *reftable_tmp
=
3301 g_malloc(s
->refcount_table_size
* sizeof(uint64_t));
3304 for (i
= 0; i
< s
->refcount_table_size
; i
++) {
3305 int64_t refblock_offs
= s
->refcount_table
[i
] & REFT_OFFSET_MASK
;
3309 if (refblock_offs
== 0) {
3310 reftable_tmp
[i
] = 0;
3313 ret
= qcow2_cache_get(bs
, s
->refcount_block_cache
, refblock_offs
,
3319 /* the refblock has own reference */
3320 if (i
== offset_to_reftable_index(s
, refblock_offs
)) {
3321 uint64_t block_index
= (refblock_offs
>> s
->cluster_bits
) &
3322 (s
->refcount_block_size
- 1);
3323 uint64_t refcount
= s
->get_refcount(refblock
, block_index
);
3325 s
->set_refcount(refblock
, block_index
, 0);
3327 unused_block
= buffer_is_zero(refblock
, s
->cluster_size
);
3329 s
->set_refcount(refblock
, block_index
, refcount
);
3331 unused_block
= buffer_is_zero(refblock
, s
->cluster_size
);
3333 qcow2_cache_put(s
->refcount_block_cache
, &refblock
);
3335 reftable_tmp
[i
] = unused_block
? 0 : cpu_to_be64(s
->refcount_table
[i
]);
3338 ret
= bdrv_pwrite_sync(bs
->file
, s
->refcount_table_offset
, reftable_tmp
,
3339 s
->refcount_table_size
* sizeof(uint64_t));
3341 * If the write in the reftable failed the image may contain a partially
3342 * overwritten reftable. In this case it would be better to clear the
3343 * reftable in memory to avoid possible image corruption.
3345 for (i
= 0; i
< s
->refcount_table_size
; i
++) {
3346 if (s
->refcount_table
[i
] && !reftable_tmp
[i
]) {
3348 ret
= qcow2_discard_refcount_block(bs
, s
->refcount_table
[i
] &
3351 s
->refcount_table
[i
] = 0;
3355 if (!s
->cache_discards
) {
3356 qcow2_process_discards(bs
, ret
);
3360 g_free(reftable_tmp
);
3364 int64_t qcow2_get_last_cluster(BlockDriverState
*bs
, int64_t size
)
3366 BDRVQcow2State
*s
= bs
->opaque
;
3369 for (i
= size_to_clusters(s
, size
) - 1; i
>= 0; i
--) {
3371 int ret
= qcow2_get_refcount(bs
, i
, &refcount
);
3373 fprintf(stderr
, "Can't get refcount for cluster %" PRId64
": %s\n",
3381 qcow2_signal_corruption(bs
, true, -1, -1,
3382 "There are no references in the refcount table.");