2 * Bitmaps for the QCOW version 2 format
4 * Copyright (c) 2014-2017 Vladimir Sementsov-Ogievskiy
6 * This file is derived from qcow2-snapshot.c, original copyright:
7 * Copyright (c) 2004-2006 Fabrice Bellard
9 * Permission is hereby granted, free of charge, to any person obtaining a copy
10 * of this software and associated documentation files (the "Software"), to deal
11 * in the Software without restriction, including without limitation the rights
12 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 * copies of the Software, and to permit persons to whom the Software is
14 * furnished to do so, subject to the following conditions:
16 * The above copyright notice and this permission notice shall be included in
17 * all copies or substantial portions of the Software.
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
28 #include "qemu/osdep.h"
29 #include "block/block-io.h"
30 #include "block/dirty-bitmap.h"
31 #include "qapi/error.h"
32 #include "qemu/cutils.h"
36 /* NOTICE: BME here means Bitmaps Extension and used as a namespace for
37 * _internal_ constants. Please do not use this _internal_ abbreviation for
38 * other needs and/or outside of this file. */
40 /* Bitmap directory entry constraints */
41 #define BME_MAX_TABLE_SIZE 0x8000000
42 #define BME_MAX_PHYS_SIZE 0x20000000 /* restrict BdrvDirtyBitmap size in RAM */
43 #define BME_MAX_GRANULARITY_BITS 31
44 #define BME_MIN_GRANULARITY_BITS 9
45 #define BME_MAX_NAME_SIZE 1023
47 /* Size of bitmap table entries */
48 #define BME_TABLE_ENTRY_SIZE (sizeof(uint64_t))
50 QEMU_BUILD_BUG_ON(BME_MAX_NAME_SIZE != BDRV_BITMAP_MAX_NAME_SIZE);
52 #if BME_MAX_TABLE_SIZE * 8ULL > INT_MAX
53 #error In the code bitmap table physical size assumed to fit into int
56 /* Bitmap directory entry flags */
57 #define BME_RESERVED_FLAGS 0xfffffffcU
58 #define BME_FLAG_IN_USE (1U << 0)
59 #define BME_FLAG_AUTO (1U << 1)
61 /* bits [1, 8] U [56, 63] are reserved */
62 #define BME_TABLE_ENTRY_RESERVED_MASK 0xff000000000001feULL
63 #define BME_TABLE_ENTRY_OFFSET_MASK 0x00fffffffffffe00ULL
64 #define BME_TABLE_ENTRY_FLAG_ALL_ONES (1ULL << 0)
66 typedef struct QEMU_PACKED Qcow2BitmapDirEntry {
67 /* header is 8 byte aligned */
68 uint64_t bitmap_table_offset;
70 uint32_t bitmap_table_size;
74 uint8_t granularity_bits;
76 uint32_t extra_data_size;
77 /* extra data follows */
79 } Qcow2BitmapDirEntry;
81 typedef struct Qcow2BitmapTable {
83 uint32_t size; /* number of 64bit entries */
84 QSIMPLEQ_ENTRY(Qcow2BitmapTable) entry;
87 typedef struct Qcow2Bitmap {
88 Qcow2BitmapTable table;
90 uint8_t granularity_bits;
93 BdrvDirtyBitmap *dirty_bitmap;
95 QSIMPLEQ_ENTRY(Qcow2Bitmap) entry;
97 typedef QSIMPLEQ_HEAD(Qcow2BitmapList, Qcow2Bitmap) Qcow2BitmapList;
99 typedef enum BitmapType {
100 BT_DIRTY_TRACKING_BITMAP = 1
103 static inline bool can_write(BlockDriverState *bs)
105 return !bdrv_is_read_only(bs) && !(bdrv_get_flags(bs) & BDRV_O_INACTIVE);
108 static int update_header_sync(BlockDriverState *bs)
112 ret = qcow2_update_header(bs);
117 return bdrv_flush(bs->file->bs);
120 static inline void bitmap_table_bswap_be(uint64_t *bitmap_table, size_t size)
124 for (i = 0; i < size; ++i) {
125 bitmap_table[i] = cpu_to_be64(bitmap_table[i]);
129 static int check_table_entry(uint64_t entry, int cluster_size)
133 if (entry & BME_TABLE_ENTRY_RESERVED_MASK) {
137 offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
139 /* if offset specified, bit 0 is reserved */
140 if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
144 if (offset % cluster_size != 0) {
152 static int64_t get_bitmap_bytes_needed(int64_t len, uint32_t granularity)
154 int64_t num_bits = DIV_ROUND_UP(len, granularity);
156 return DIV_ROUND_UP(num_bits, 8);
159 static int check_constraints_on_bitmap(BlockDriverState *bs,
161 uint32_t granularity,
164 BDRVQcow2State *s = bs->opaque;
165 int granularity_bits = ctz32(granularity);
166 int64_t len = bdrv_getlength(bs);
167 int64_t bitmap_bytes;
169 assume_graph_lock(); /* FIXME */
171 assert(granularity > 0);
172 assert((granularity & (granularity - 1)) == 0);
175 error_setg_errno(errp, -len, "Failed to get size of '%s'",
176 bdrv_get_device_or_node_name(bs));
180 if (granularity_bits > BME_MAX_GRANULARITY_BITS) {
181 error_setg(errp, "Granularity exceeds maximum (%llu bytes)",
182 1ULL << BME_MAX_GRANULARITY_BITS);
185 if (granularity_bits < BME_MIN_GRANULARITY_BITS) {
186 error_setg(errp, "Granularity is under minimum (%llu bytes)",
187 1ULL << BME_MIN_GRANULARITY_BITS);
191 bitmap_bytes = get_bitmap_bytes_needed(len, granularity);
192 if ((bitmap_bytes > (uint64_t)BME_MAX_PHYS_SIZE) ||
193 (bitmap_bytes > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size))
195 error_setg(errp, "Too much space will be occupied by the bitmap. "
196 "Use larger granularity");
200 if (strlen(name) > BME_MAX_NAME_SIZE) {
201 error_setg(errp, "Name length exceeds maximum (%u characters)",
209 static void clear_bitmap_table(BlockDriverState *bs, uint64_t *bitmap_table,
210 uint32_t bitmap_table_size)
212 BDRVQcow2State *s = bs->opaque;
215 for (i = 0; i < bitmap_table_size; ++i) {
216 uint64_t addr = bitmap_table[i] & BME_TABLE_ENTRY_OFFSET_MASK;
221 qcow2_free_clusters(bs, addr, s->cluster_size, QCOW2_DISCARD_ALWAYS);
226 static int bitmap_table_load(BlockDriverState *bs, Qcow2BitmapTable *tb,
227 uint64_t **bitmap_table)
230 BDRVQcow2State *s = bs->opaque;
234 assert(tb->size != 0);
235 table = g_try_new(uint64_t, tb->size);
240 assert(tb->size <= BME_MAX_TABLE_SIZE);
241 ret = bdrv_pread(bs->file, tb->offset, tb->size * BME_TABLE_ENTRY_SIZE,
247 for (i = 0; i < tb->size; ++i) {
248 table[i] = be64_to_cpu(table[i]);
249 ret = check_table_entry(table[i], s->cluster_size);
255 *bitmap_table = table;
264 static int free_bitmap_clusters(BlockDriverState *bs, Qcow2BitmapTable *tb)
267 uint64_t *bitmap_table;
269 ret = bitmap_table_load(bs, tb, &bitmap_table);
274 clear_bitmap_table(bs, bitmap_table, tb->size);
275 qcow2_free_clusters(bs, tb->offset, tb->size * BME_TABLE_ENTRY_SIZE,
276 QCOW2_DISCARD_OTHER);
277 g_free(bitmap_table);
286 * @bitmap_table entries must satisfy specification constraints.
287 * @bitmap must be cleared */
288 static int coroutine_fn GRAPH_RDLOCK
289 load_bitmap_data(BlockDriverState *bs, const uint64_t *bitmap_table,
290 uint32_t bitmap_table_size, BdrvDirtyBitmap *bitmap)
293 BDRVQcow2State *s = bs->opaque;
294 uint64_t offset, limit;
295 uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
297 uint64_t i, tab_size =
299 bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
301 if (tab_size != bitmap_table_size || tab_size > BME_MAX_TABLE_SIZE) {
305 buf = g_malloc(s->cluster_size);
306 limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap);
307 for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
308 uint64_t count = MIN(bm_size - offset, limit);
309 uint64_t entry = bitmap_table[i];
310 uint64_t data_offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
312 assert(check_table_entry(entry, s->cluster_size) == 0);
314 if (data_offset == 0) {
315 if (entry & BME_TABLE_ENTRY_FLAG_ALL_ONES) {
316 bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count,
319 /* No need to deserialize zeros because the dirty bitmap is
323 ret = bdrv_co_pread(bs->file, data_offset, s->cluster_size, buf, 0);
327 bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
333 bdrv_dirty_bitmap_deserialize_finish(bitmap);
341 static coroutine_fn GRAPH_RDLOCK
342 BdrvDirtyBitmap *load_bitmap(BlockDriverState *bs,
343 Qcow2Bitmap *bm, Error **errp)
346 uint64_t *bitmap_table = NULL;
347 uint32_t granularity;
348 BdrvDirtyBitmap *bitmap = NULL;
350 granularity = 1U << bm->granularity_bits;
351 bitmap = bdrv_create_dirty_bitmap(bs, granularity, bm->name, errp);
352 if (bitmap == NULL) {
356 if (bm->flags & BME_FLAG_IN_USE) {
357 /* Data is unusable, skip loading it */
361 ret = bitmap_table_load(bs, &bm->table, &bitmap_table);
363 error_setg_errno(errp, -ret,
364 "Could not read bitmap_table table from image for "
365 "bitmap '%s'", bm->name);
369 ret = load_bitmap_data(bs, bitmap_table, bm->table.size, bitmap);
371 error_setg_errno(errp, -ret, "Could not read bitmap '%s' from image",
376 g_free(bitmap_table);
380 g_free(bitmap_table);
381 if (bitmap != NULL) {
382 bdrv_release_dirty_bitmap(bitmap);
393 * Bitmap List private functions
394 * Only Bitmap List knows about bitmap directory structure in Qcow2.
397 static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry)
399 entry->bitmap_table_offset = be64_to_cpu(entry->bitmap_table_offset);
400 entry->bitmap_table_size = be32_to_cpu(entry->bitmap_table_size);
401 entry->flags = be32_to_cpu(entry->flags);
402 entry->name_size = be16_to_cpu(entry->name_size);
403 entry->extra_data_size = be32_to_cpu(entry->extra_data_size);
406 static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry)
408 entry->bitmap_table_offset = cpu_to_be64(entry->bitmap_table_offset);
409 entry->bitmap_table_size = cpu_to_be32(entry->bitmap_table_size);
410 entry->flags = cpu_to_be32(entry->flags);
411 entry->name_size = cpu_to_be16(entry->name_size);
412 entry->extra_data_size = cpu_to_be32(entry->extra_data_size);
415 static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size)
417 int size = sizeof(Qcow2BitmapDirEntry) + name_size + extra_data_size;
418 return ROUND_UP(size, 8);
421 static inline int dir_entry_size(Qcow2BitmapDirEntry *entry)
423 return calc_dir_entry_size(entry->name_size, entry->extra_data_size);
426 static inline const char *dir_entry_name_field(Qcow2BitmapDirEntry *entry)
428 return (const char *)(entry + 1) + entry->extra_data_size;
431 static inline char *dir_entry_copy_name(Qcow2BitmapDirEntry *entry)
433 const char *name_field = dir_entry_name_field(entry);
434 return g_strndup(name_field, entry->name_size);
437 static inline Qcow2BitmapDirEntry *next_dir_entry(Qcow2BitmapDirEntry *entry)
439 return (Qcow2BitmapDirEntry *)((uint8_t *)entry + dir_entry_size(entry));
442 static int check_dir_entry(BlockDriverState *bs, Qcow2BitmapDirEntry *entry)
444 BDRVQcow2State *s = bs->opaque;
445 uint64_t phys_bitmap_bytes;
448 bool fail = (entry->bitmap_table_size == 0) ||
449 (entry->bitmap_table_offset == 0) ||
450 (entry->bitmap_table_offset % s->cluster_size) ||
451 (entry->bitmap_table_size > BME_MAX_TABLE_SIZE) ||
452 (entry->granularity_bits > BME_MAX_GRANULARITY_BITS) ||
453 (entry->granularity_bits < BME_MIN_GRANULARITY_BITS) ||
454 (entry->flags & BME_RESERVED_FLAGS) ||
455 (entry->name_size > BME_MAX_NAME_SIZE) ||
456 (entry->type != BT_DIRTY_TRACKING_BITMAP);
462 phys_bitmap_bytes = (uint64_t)entry->bitmap_table_size * s->cluster_size;
463 len = bdrv_getlength(bs);
469 if (phys_bitmap_bytes > BME_MAX_PHYS_SIZE) {
473 if (!(entry->flags & BME_FLAG_IN_USE) &&
474 (len > ((phys_bitmap_bytes * 8) << entry->granularity_bits)))
477 * We've loaded a valid bitmap (IN_USE not set) or we are going to
478 * store a valid bitmap, but the allocated bitmap table size is not
479 * enough to store this bitmap.
481 * Note, that it's OK to have an invalid bitmap with invalid size due
482 * to a bitmap that was not correctly saved after image resize.
490 static inline void bitmap_directory_to_be(uint8_t *dir, size_t size)
492 uint8_t *end = dir + size;
494 Qcow2BitmapDirEntry *e = (Qcow2BitmapDirEntry *)dir;
495 dir += dir_entry_size(e);
497 bitmap_dir_entry_to_be(e);
502 * Bitmap List public functions
505 static void bitmap_free(Qcow2Bitmap *bm)
515 static void bitmap_list_free(Qcow2BitmapList *bm_list)
519 if (bm_list == NULL) {
523 while ((bm = QSIMPLEQ_FIRST(bm_list)) != NULL) {
524 QSIMPLEQ_REMOVE_HEAD(bm_list, entry);
531 static Qcow2BitmapList *bitmap_list_new(void)
533 Qcow2BitmapList *bm_list = g_new(Qcow2BitmapList, 1);
534 QSIMPLEQ_INIT(bm_list);
539 static uint32_t bitmap_list_count(Qcow2BitmapList *bm_list)
542 uint32_t nb_bitmaps = 0;
544 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
552 * Get bitmap list from qcow2 image. Actually reads bitmap directory,
553 * checks it and convert to bitmap list.
555 static Qcow2BitmapList *bitmap_list_load(BlockDriverState *bs, uint64_t offset,
556 uint64_t size, Error **errp)
559 BDRVQcow2State *s = bs->opaque;
560 uint8_t *dir, *dir_end;
561 Qcow2BitmapDirEntry *e;
562 uint32_t nb_dir_entries = 0;
563 Qcow2BitmapList *bm_list = NULL;
566 error_setg(errp, "Requested bitmap directory size is zero");
570 if (size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
571 error_setg(errp, "Requested bitmap directory size is too big");
575 dir = g_try_malloc(size);
577 error_setg(errp, "Failed to allocate space for bitmap directory");
580 dir_end = dir + size;
582 ret = bdrv_pread(bs->file, offset, size, dir, 0);
584 error_setg_errno(errp, -ret, "Failed to read bitmap directory");
588 bm_list = bitmap_list_new();
589 for (e = (Qcow2BitmapDirEntry *)dir;
590 e < (Qcow2BitmapDirEntry *)dir_end;
591 e = next_dir_entry(e))
595 if ((uint8_t *)(e + 1) > dir_end) {
599 if (++nb_dir_entries > s->nb_bitmaps) {
600 error_setg(errp, "More bitmaps found than specified in header"
604 bitmap_dir_entry_to_cpu(e);
606 if ((uint8_t *)next_dir_entry(e) > dir_end) {
610 if (e->extra_data_size != 0) {
611 error_setg(errp, "Bitmap extra data is not supported");
615 ret = check_dir_entry(bs, e);
617 error_setg(errp, "Bitmap '%.*s' doesn't satisfy the constraints",
618 e->name_size, dir_entry_name_field(e));
622 bm = g_new0(Qcow2Bitmap, 1);
623 bm->table.offset = e->bitmap_table_offset;
624 bm->table.size = e->bitmap_table_size;
625 bm->flags = e->flags;
626 bm->granularity_bits = e->granularity_bits;
627 bm->name = dir_entry_copy_name(e);
628 QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry);
631 if (nb_dir_entries != s->nb_bitmaps) {
632 error_setg(errp, "Less bitmaps found than specified in header"
637 if ((uint8_t *)e != dir_end) {
645 error_setg(errp, "Broken bitmap directory");
649 bitmap_list_free(bm_list);
655 qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
656 void **refcount_table,
657 int64_t *refcount_table_size)
660 BDRVQcow2State *s = bs->opaque;
661 Qcow2BitmapList *bm_list;
664 if (s->nb_bitmaps == 0) {
668 ret = qcow2_inc_refcounts_imrt(bs, res, refcount_table, refcount_table_size,
669 s->bitmap_directory_offset,
670 s->bitmap_directory_size);
675 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
676 s->bitmap_directory_size, NULL);
677 if (bm_list == NULL) {
682 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
683 uint64_t *bitmap_table = NULL;
686 ret = qcow2_inc_refcounts_imrt(bs, res,
687 refcount_table, refcount_table_size,
689 bm->table.size * BME_TABLE_ENTRY_SIZE);
694 ret = bitmap_table_load(bs, &bm->table, &bitmap_table);
700 for (i = 0; i < bm->table.size; ++i) {
701 uint64_t entry = bitmap_table[i];
702 uint64_t offset = entry & BME_TABLE_ENTRY_OFFSET_MASK;
704 if (check_table_entry(entry, s->cluster_size) < 0) {
713 ret = qcow2_inc_refcounts_imrt(bs, res,
714 refcount_table, refcount_table_size,
715 offset, s->cluster_size);
717 g_free(bitmap_table);
722 g_free(bitmap_table);
726 bitmap_list_free(bm_list);
732 * Store bitmap list to qcow2 image as a bitmap directory.
733 * Everything is checked.
735 static int bitmap_list_store(BlockDriverState *bs, Qcow2BitmapList *bm_list,
736 uint64_t *offset, uint64_t *size, bool in_place)
740 int64_t dir_offset = 0;
741 uint64_t dir_size = 0;
743 Qcow2BitmapDirEntry *e;
745 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
746 dir_size += calc_dir_entry_size(strlen(bm->name), 0);
749 if (dir_size == 0 || dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
754 if (*size != dir_size || *offset == 0) {
758 dir_offset = *offset;
761 dir = g_try_malloc0(dir_size);
766 e = (Qcow2BitmapDirEntry *)dir;
767 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
768 e->bitmap_table_offset = bm->table.offset;
769 e->bitmap_table_size = bm->table.size;
770 e->flags = bm->flags;
771 e->type = BT_DIRTY_TRACKING_BITMAP;
772 e->granularity_bits = bm->granularity_bits;
773 e->name_size = strlen(bm->name);
774 e->extra_data_size = 0;
775 memcpy(e + 1, bm->name, e->name_size);
777 if (check_dir_entry(bs, e) < 0) {
782 e = next_dir_entry(e);
785 bitmap_directory_to_be(dir, dir_size);
788 dir_offset = qcow2_alloc_clusters(bs, dir_size);
789 if (dir_offset < 0) {
795 /* Actually, even in the in-place case ignoring QCOW2_OL_BITMAP_DIRECTORY
796 * is not necessary, because we drop QCOW2_AUTOCLEAR_BITMAPS when updating
797 * bitmap directory in-place (actually, turn-off the extension), which is
798 * checked in qcow2_check_metadata_overlap() */
799 ret = qcow2_pre_write_overlap_check(
800 bs, in_place ? QCOW2_OL_BITMAP_DIRECTORY : 0, dir_offset, dir_size,
806 ret = bdrv_pwrite(bs->file, dir_offset, dir_size, dir, 0);
815 *offset = dir_offset;
823 if (!in_place && dir_offset > 0) {
824 qcow2_free_clusters(bs, dir_offset, dir_size, QCOW2_DISCARD_OTHER);
834 static int update_ext_header_and_dir_in_place(BlockDriverState *bs,
835 Qcow2BitmapList *bm_list)
837 BDRVQcow2State *s = bs->opaque;
840 if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS) ||
841 bm_list == NULL || QSIMPLEQ_EMPTY(bm_list) ||
842 bitmap_list_count(bm_list) != s->nb_bitmaps)
847 s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
848 ret = update_header_sync(bs);
850 /* Two variants are possible here:
851 * 1. Autoclear flag is dropped, all bitmaps will be lost.
852 * 2. Autoclear flag is not dropped, old state is left.
857 /* autoclear bit is not set, so we can safely update bitmap directory */
859 ret = bitmap_list_store(bs, bm_list, &s->bitmap_directory_offset,
860 &s->bitmap_directory_size, true);
862 /* autoclear bit is cleared, so all leaked clusters would be removed on
867 ret = update_header_sync(bs);
869 /* autoclear bit is cleared, so all leaked clusters would be removed on
874 s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
875 return update_header_sync(bs);
876 /* If final update_header_sync() fails, two variants are possible:
877 * 1. Autoclear flag is not set, all bitmaps will be lost.
878 * 2. Autoclear flag is set, header and directory are successfully updated.
882 static int update_ext_header_and_dir(BlockDriverState *bs,
883 Qcow2BitmapList *bm_list)
885 BDRVQcow2State *s = bs->opaque;
887 uint64_t new_offset = 0;
888 uint64_t new_size = 0;
889 uint32_t new_nb_bitmaps = 0;
890 uint64_t old_offset = s->bitmap_directory_offset;
891 uint64_t old_size = s->bitmap_directory_size;
892 uint32_t old_nb_bitmaps = s->nb_bitmaps;
893 uint64_t old_autocl = s->autoclear_features;
895 if (bm_list != NULL && !QSIMPLEQ_EMPTY(bm_list)) {
896 new_nb_bitmaps = bitmap_list_count(bm_list);
898 if (new_nb_bitmaps > QCOW2_MAX_BITMAPS) {
902 ret = bitmap_list_store(bs, bm_list, &new_offset, &new_size, false);
907 ret = qcow2_flush_caches(bs);
912 s->autoclear_features |= QCOW2_AUTOCLEAR_BITMAPS;
914 s->autoclear_features &= ~(uint64_t)QCOW2_AUTOCLEAR_BITMAPS;
917 s->bitmap_directory_offset = new_offset;
918 s->bitmap_directory_size = new_size;
919 s->nb_bitmaps = new_nb_bitmaps;
921 ret = update_header_sync(bs);
927 qcow2_free_clusters(bs, old_offset, old_size, QCOW2_DISCARD_OTHER);
933 if (new_offset > 0) {
934 qcow2_free_clusters(bs, new_offset, new_size, QCOW2_DISCARD_OTHER);
937 s->bitmap_directory_offset = old_offset;
938 s->bitmap_directory_size = old_size;
939 s->nb_bitmaps = old_nb_bitmaps;
940 s->autoclear_features = old_autocl;
945 /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */
946 static void release_dirty_bitmap_helper(gpointer bitmap,
949 bdrv_release_dirty_bitmap(bitmap);
952 /* for g_slist_foreach for GSList of BdrvDirtyBitmap* elements */
953 static void set_readonly_helper(gpointer bitmap, gpointer value)
955 bdrv_dirty_bitmap_set_readonly(bitmap, (bool)value);
959 * Return true on success, false on failure.
960 * If header_updated is not NULL then it is set appropriately regardless of
963 bool coroutine_fn GRAPH_RDLOCK
964 qcow2_load_dirty_bitmaps(BlockDriverState *bs,
965 bool *header_updated, Error **errp)
967 BDRVQcow2State *s = bs->opaque;
968 Qcow2BitmapList *bm_list;
970 GSList *created_dirty_bitmaps = NULL;
971 bool needs_update = false;
973 if (header_updated) {
974 *header_updated = false;
977 if (s->nb_bitmaps == 0) {
978 /* No bitmaps - nothing to do */
982 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
983 s->bitmap_directory_size, errp);
984 if (bm_list == NULL) {
988 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
989 BdrvDirtyBitmap *bitmap;
991 if ((bm->flags & BME_FLAG_IN_USE) &&
992 bdrv_find_dirty_bitmap(bs, bm->name))
995 * We already have corresponding BdrvDirtyBitmap, and bitmap in the
996 * image is marked IN_USE. Firstly, this state is valid, no reason
997 * to consider existing BdrvDirtyBitmap to be bad. Secondly it's
998 * absolutely possible, when we do migration with shared storage
999 * with dirty-bitmaps capability enabled: if the bitmap was loaded
1000 * from this storage before migration start, the storage will
1001 * of-course contain IN_USE outdated version of the bitmap, and we
1002 * should not load it on migration target, as we already have this
1003 * bitmap, being migrated.
1008 bitmap = load_bitmap(bs, bm, errp);
1009 if (bitmap == NULL) {
1013 bdrv_dirty_bitmap_set_persistence(bitmap, true);
1014 if (bm->flags & BME_FLAG_IN_USE) {
1015 bdrv_dirty_bitmap_set_inconsistent(bitmap);
1017 /* NB: updated flags only get written if can_write(bs) is true. */
1018 bm->flags |= BME_FLAG_IN_USE;
1019 needs_update = true;
1021 if (!(bm->flags & BME_FLAG_AUTO)) {
1022 bdrv_disable_dirty_bitmap(bitmap);
1024 created_dirty_bitmaps =
1025 g_slist_append(created_dirty_bitmaps, bitmap);
1028 if (needs_update && can_write(bs)) {
1029 /* in_use flags must be updated */
1030 int ret = update_ext_header_and_dir_in_place(bs, bm_list);
1032 error_setg_errno(errp, -ret, "Can't update bitmap directory");
1035 if (header_updated) {
1036 *header_updated = true;
1040 if (!can_write(bs)) {
1041 g_slist_foreach(created_dirty_bitmaps, set_readonly_helper,
1045 g_slist_free(created_dirty_bitmaps);
1046 bitmap_list_free(bm_list);
1051 g_slist_foreach(created_dirty_bitmaps, release_dirty_bitmap_helper, bs);
1052 g_slist_free(created_dirty_bitmaps);
1053 bitmap_list_free(bm_list);
1059 static Qcow2BitmapInfoFlagsList *get_bitmap_info_flags(uint32_t flags)
1061 Qcow2BitmapInfoFlagsList *list = NULL;
1062 Qcow2BitmapInfoFlagsList **tail = &list;
1065 static const struct {
1066 int bme; /* Bitmap directory entry flags */
1067 int info; /* The flags to report to the user */
1069 { BME_FLAG_IN_USE, QCOW2_BITMAP_INFO_FLAGS_IN_USE },
1070 { BME_FLAG_AUTO, QCOW2_BITMAP_INFO_FLAGS_AUTO },
1073 int map_size = ARRAY_SIZE(map);
1075 for (i = 0; i < map_size; ++i) {
1076 if (flags & map[i].bme) {
1077 QAPI_LIST_APPEND(tail, map[i].info);
1078 flags &= ~map[i].bme;
1081 /* Check if the BME_* mapping above is complete */
1088 * qcow2_get_bitmap_info_list()
1089 * Returns a list of QCOW2 bitmap details.
1090 * On success return true with info_list set (note, that if there are no
1091 * bitmaps, info_list is set to NULL).
1092 * On failure return false with errp set.
1094 bool qcow2_get_bitmap_info_list(BlockDriverState *bs,
1095 Qcow2BitmapInfoList **info_list, Error **errp)
1097 BDRVQcow2State *s = bs->opaque;
1098 Qcow2BitmapList *bm_list;
1100 Qcow2BitmapInfoList **tail;
1102 if (s->nb_bitmaps == 0) {
1107 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1108 s->bitmap_directory_size, errp);
1116 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1117 Qcow2BitmapInfo *info = g_new0(Qcow2BitmapInfo, 1);
1118 info->granularity = 1U << bm->granularity_bits;
1119 info->name = g_strdup(bm->name);
1120 info->flags = get_bitmap_info_flags(bm->flags & ~BME_RESERVED_FLAGS);
1121 QAPI_LIST_APPEND(tail, info);
1124 bitmap_list_free(bm_list);
1129 int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
1131 BDRVQcow2State *s = bs->opaque;
1132 Qcow2BitmapList *bm_list;
1134 GSList *ro_dirty_bitmaps = NULL;
1136 bool need_header_update = false;
1138 if (s->nb_bitmaps == 0) {
1139 /* No bitmaps - nothing to do */
1143 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1144 s->bitmap_directory_size, errp);
1145 if (bm_list == NULL) {
1149 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1150 BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name);
1153 error_setg(errp, "Unexpected bitmap '%s' in image '%s'",
1154 bm->name, bs->filename);
1158 if (!(bm->flags & BME_FLAG_IN_USE)) {
1159 if (!bdrv_dirty_bitmap_readonly(bitmap)) {
1160 error_setg(errp, "Corruption: bitmap '%s' is not marked IN_USE "
1161 "in the image '%s' and not marked readonly in RAM",
1162 bm->name, bs->filename);
1165 if (bdrv_dirty_bitmap_inconsistent(bitmap)) {
1166 error_setg(errp, "Corruption: bitmap '%s' is inconsistent but "
1167 "is not marked IN_USE in the image '%s'", bm->name,
1172 bm->flags |= BME_FLAG_IN_USE;
1173 need_header_update = true;
1176 * What if flags already has BME_FLAG_IN_USE ?
1178 * 1. if we are reopening RW -> RW it's OK, of course.
1179 * 2. if we are reopening RO -> RW:
1180 * 2.1 if @bitmap is inconsistent, it's OK. It means that it was
1181 * inconsistent (IN_USE) when we loaded it
1182 * 2.2 if @bitmap is not inconsistent. This seems to be impossible
1183 * and implies third party interaction. Let's error-out for
1186 if (bdrv_dirty_bitmap_readonly(bitmap) &&
1187 !bdrv_dirty_bitmap_inconsistent(bitmap))
1189 error_setg(errp, "Corruption: bitmap '%s' is marked IN_USE "
1190 "in the image '%s' but it is readonly and "
1191 "consistent in RAM",
1192 bm->name, bs->filename);
1197 if (bdrv_dirty_bitmap_readonly(bitmap)) {
1198 ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap);
1202 if (need_header_update) {
1203 if (!can_write(bs->file->bs) || !(bs->file->perm & BLK_PERM_WRITE)) {
1204 error_setg(errp, "Failed to reopen bitmaps rw: no write access "
1205 "the protocol file");
1209 /* in_use flags must be updated */
1210 ret = update_ext_header_and_dir_in_place(bs, bm_list);
1212 error_setg_errno(errp, -ret, "Cannot update bitmap directory");
1217 g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, (gpointer)false);
1221 g_slist_free(ro_dirty_bitmaps);
1222 bitmap_list_free(bm_list);
1227 /* Checks to see if it's safe to resize bitmaps */
1228 int coroutine_fn qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp)
1230 BDRVQcow2State *s = bs->opaque;
1231 Qcow2BitmapList *bm_list;
1235 if (s->nb_bitmaps == 0) {
1239 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1240 s->bitmap_directory_size, errp);
1241 if (bm_list == NULL) {
1245 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1246 BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name);
1247 if (bitmap == NULL) {
1249 * We rely on all bitmaps being in-memory to be able to resize them,
1250 * Otherwise, we'd need to resize them on disk explicitly
1252 error_setg(errp, "Cannot resize qcow2 with persistent bitmaps that "
1253 "were not loaded into memory");
1259 * The checks against readonly and busy are redundant, but certainly
1260 * do no harm. checks against inconsistent are crucial:
1262 if (bdrv_dirty_bitmap_check(bitmap, BDRV_BITMAP_DEFAULT, errp)) {
1269 bitmap_list_free(bm_list);
1273 /* store_bitmap_data()
1274 * Store bitmap to image, filling bitmap table accordingly.
1276 static uint64_t *store_bitmap_data(BlockDriverState *bs,
1277 BdrvDirtyBitmap *bitmap,
1278 uint32_t *bitmap_table_size, Error **errp)
1281 BDRVQcow2State *s = bs->opaque;
1284 uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
1285 const char *bm_name = bdrv_dirty_bitmap_name(bitmap);
1286 uint8_t *buf = NULL;
1290 bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size));
1292 if (tb_size > BME_MAX_TABLE_SIZE ||
1293 tb_size * s->cluster_size > BME_MAX_PHYS_SIZE)
1295 error_setg(errp, "Bitmap '%s' is too big", bm_name);
1299 tb = g_try_new0(uint64_t, tb_size);
1301 error_setg(errp, "No memory");
1305 buf = g_malloc(s->cluster_size);
1306 limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap);
1307 assert(DIV_ROUND_UP(bm_size, limit) == tb_size);
1310 while ((offset = bdrv_dirty_bitmap_next_dirty(bitmap, offset, INT64_MAX))
1313 uint64_t cluster = offset / limit;
1314 uint64_t end, write_size;
1318 * We found the first dirty offset, but want to write out the
1319 * entire cluster of the bitmap that includes that offset,
1320 * including any leading zero bits.
1322 offset = QEMU_ALIGN_DOWN(offset, limit);
1323 end = MIN(bm_size, offset + limit);
1324 write_size = bdrv_dirty_bitmap_serialization_size(bitmap, offset,
1326 assert(write_size <= s->cluster_size);
1328 off = qcow2_alloc_clusters(bs, s->cluster_size);
1330 error_setg_errno(errp, -off,
1331 "Failed to allocate clusters for bitmap '%s'",
1337 bdrv_dirty_bitmap_serialize_part(bitmap, buf, offset, end - offset);
1338 if (write_size < s->cluster_size) {
1339 memset(buf + write_size, 0, s->cluster_size - write_size);
1342 ret = qcow2_pre_write_overlap_check(bs, 0, off, s->cluster_size, false);
1344 error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
1348 ret = bdrv_pwrite(bs->file, off, s->cluster_size, buf, 0);
1350 error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file",
1358 *bitmap_table_size = tb_size;
1364 clear_bitmap_table(bs, tb, tb_size);
1372 * Store bm->dirty_bitmap to qcow2.
1373 * Set bm->table_offset and bm->table_size accordingly.
1375 static int store_bitmap(BlockDriverState *bs, Qcow2Bitmap *bm, Error **errp)
1381 BdrvDirtyBitmap *bitmap = bm->dirty_bitmap;
1382 const char *bm_name;
1384 assert(bitmap != NULL);
1386 bm_name = bdrv_dirty_bitmap_name(bitmap);
1388 tb = store_bitmap_data(bs, bitmap, &tb_size, errp);
1393 assert(tb_size <= BME_MAX_TABLE_SIZE);
1394 tb_offset = qcow2_alloc_clusters(bs, tb_size * sizeof(tb[0]));
1395 if (tb_offset < 0) {
1396 error_setg_errno(errp, -tb_offset,
1397 "Failed to allocate clusters for bitmap '%s'",
1403 ret = qcow2_pre_write_overlap_check(bs, 0, tb_offset,
1404 tb_size * sizeof(tb[0]), false);
1406 error_setg_errno(errp, -ret, "Qcow2 overlap check failed");
1410 bitmap_table_bswap_be(tb, tb_size);
1411 ret = bdrv_pwrite(bs->file, tb_offset, tb_size * sizeof(tb[0]), tb, 0);
1413 bitmap_table_bswap_be(tb, tb_size);
1414 error_setg_errno(errp, -ret, "Failed to write bitmap '%s' to file",
1421 bm->table.offset = tb_offset;
1422 bm->table.size = tb_size;
1427 clear_bitmap_table(bs, tb, tb_size);
1429 if (tb_offset > 0) {
1430 qcow2_free_clusters(bs, tb_offset, tb_size * sizeof(tb[0]),
1431 QCOW2_DISCARD_OTHER);
1439 static Qcow2Bitmap *find_bitmap_by_name(Qcow2BitmapList *bm_list,
1444 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1445 if (strcmp(name, bm->name) == 0) {
1453 int coroutine_fn qcow2_co_remove_persistent_dirty_bitmap(BlockDriverState *bs,
1458 BDRVQcow2State *s = bs->opaque;
1459 Qcow2Bitmap *bm = NULL;
1460 Qcow2BitmapList *bm_list;
1462 if (s->nb_bitmaps == 0) {
1464 * Absence of the bitmap is not an error: see explanation above
1465 * bdrv_co_remove_persistent_dirty_bitmap() definition.
1470 qemu_co_mutex_lock(&s->lock);
1472 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1473 s->bitmap_directory_size, errp);
1474 if (bm_list == NULL) {
1479 bm = find_bitmap_by_name(bm_list, name);
1481 /* Absence of the bitmap is not an error, see above. */
1486 QSIMPLEQ_REMOVE(bm_list, bm, Qcow2Bitmap, entry);
1488 ret = update_ext_header_and_dir(bs, bm_list);
1490 error_setg_errno(errp, -ret, "Failed to update bitmap extension");
1494 free_bitmap_clusters(bs, &bm->table);
1497 qemu_co_mutex_unlock(&s->lock);
1500 bitmap_list_free(bm_list);
1506 * qcow2_store_persistent_dirty_bitmaps
1508 * Stores persistent BdrvDirtyBitmap objects.
1510 * @release_stored: if true, release BdrvDirtyBitmap's after storing to the
1511 * image. This is used in two cases, both via qcow2_inactivate:
1512 * 1. bdrv_close: It's correct to remove bitmaps on close.
1513 * 2. migration: If bitmaps are migrated through migration channel via
1514 * 'dirty-bitmaps' migration capability they are not handled by this code.
1515 * Otherwise, it's OK to drop BdrvDirtyBitmap's and reload them on
1518 * Anyway, it's correct to remove BdrvDirtyBitmap's on inactivation, as
1519 * inactivation means that we lose control on disk, and therefore on bitmaps,
1520 * we should sync them and do not touch more.
1522 * Contrariwise, we don't want to release any bitmaps on just reopen-to-ro,
1523 * when we need to store them, as image is still under our control, and it's
1524 * good to keep all the bitmaps in read-only mode. Moreover, keeping them
1525 * read-only is correct because this is what would happen if we opened the node
1526 * readonly to begin with, and whether we opened directly or reopened to that
1527 * state shouldn't matter for the state we get afterward.
1529 bool qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs,
1530 bool release_stored, Error **errp)
1533 BdrvDirtyBitmap *bitmap;
1534 BDRVQcow2State *s = bs->opaque;
1535 uint32_t new_nb_bitmaps = s->nb_bitmaps;
1536 uint64_t new_dir_size = s->bitmap_directory_size;
1538 Qcow2BitmapList *bm_list;
1540 QSIMPLEQ_HEAD(, Qcow2BitmapTable) drop_tables;
1541 Qcow2BitmapTable *tb, *tb_next;
1542 bool need_write = false;
1544 QSIMPLEQ_INIT(&drop_tables);
1546 if (s->nb_bitmaps == 0) {
1547 bm_list = bitmap_list_new();
1549 bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
1550 s->bitmap_directory_size, errp);
1551 if (bm_list == NULL) {
1556 /* check constraints and names */
1557 FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
1558 const char *name = bdrv_dirty_bitmap_name(bitmap);
1559 uint32_t granularity = bdrv_dirty_bitmap_granularity(bitmap);
1561 if (!bdrv_dirty_bitmap_get_persistence(bitmap) ||
1562 bdrv_dirty_bitmap_inconsistent(bitmap)) {
1566 if (bdrv_dirty_bitmap_readonly(bitmap)) {
1568 * Store the bitmap in the associated Qcow2Bitmap so it
1569 * can be released later
1571 bm = find_bitmap_by_name(bm_list, name);
1573 bm->dirty_bitmap = bitmap;
1580 if (check_constraints_on_bitmap(bs, name, granularity, errp) < 0) {
1581 error_prepend(errp, "Bitmap '%s' doesn't satisfy the constraints: ",
1586 bm = find_bitmap_by_name(bm_list, name);
1588 if (++new_nb_bitmaps > QCOW2_MAX_BITMAPS) {
1589 error_setg(errp, "Too many persistent bitmaps");
1593 new_dir_size += calc_dir_entry_size(strlen(name), 0);
1594 if (new_dir_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
1595 error_setg(errp, "Bitmap directory is too large");
1599 bm = g_new0(Qcow2Bitmap, 1);
1600 bm->name = g_strdup(name);
1601 QSIMPLEQ_INSERT_TAIL(bm_list, bm, entry);
1603 if (!(bm->flags & BME_FLAG_IN_USE)) {
1604 error_setg(errp, "Bitmap '%s' already exists in the image",
1608 tb = g_memdup(&bm->table, sizeof(bm->table));
1609 bm->table.offset = 0;
1611 QSIMPLEQ_INSERT_TAIL(&drop_tables, tb, entry);
1613 bm->flags = bdrv_dirty_bitmap_enabled(bitmap) ? BME_FLAG_AUTO : 0;
1614 bm->granularity_bits = ctz32(bdrv_dirty_bitmap_granularity(bitmap));
1615 bm->dirty_bitmap = bitmap;
1622 if (!can_write(bs)) {
1623 error_setg(errp, "No write access");
1627 /* allocate clusters and store bitmaps */
1628 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1629 bitmap = bm->dirty_bitmap;
1631 if (bitmap == NULL || bdrv_dirty_bitmap_readonly(bitmap)) {
1635 ret = store_bitmap(bs, bm, errp);
1641 ret = update_ext_header_and_dir(bs, bm_list);
1643 error_setg_errno(errp, -ret, "Failed to update bitmap extension");
1647 /* Bitmap directory was successfully updated, so, old data can be dropped.
1648 * TODO it is better to reuse these clusters */
1649 QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) {
1650 free_bitmap_clusters(bs, tb);
1655 if (release_stored) {
1656 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1657 if (bm->dirty_bitmap == NULL) {
1661 bdrv_release_dirty_bitmap(bm->dirty_bitmap);
1665 bitmap_list_free(bm_list);
1669 QSIMPLEQ_FOREACH(bm, bm_list, entry) {
1670 if (bm->dirty_bitmap == NULL || bm->table.offset == 0 ||
1671 bdrv_dirty_bitmap_readonly(bm->dirty_bitmap))
1676 free_bitmap_clusters(bs, &bm->table);
1679 QSIMPLEQ_FOREACH_SAFE(tb, &drop_tables, entry, tb_next) {
1683 bitmap_list_free(bm_list);
1687 int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp)
1689 BdrvDirtyBitmap *bitmap;
1691 if (!qcow2_store_persistent_dirty_bitmaps(bs, false, errp)) {
1695 FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
1696 if (bdrv_dirty_bitmap_get_persistence(bitmap)) {
1697 bdrv_dirty_bitmap_set_readonly(bitmap, true);
1704 bool coroutine_fn qcow2_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
1706 uint32_t granularity,
1709 BDRVQcow2State *s = bs->opaque;
1710 BdrvDirtyBitmap *bitmap;
1711 uint64_t bitmap_directory_size = 0;
1712 uint32_t nb_bitmaps = 0;
1714 if (bdrv_find_dirty_bitmap(bs, name)) {
1715 error_setg(errp, "Bitmap already exists: %s", name);
1719 if (s->qcow_version < 3) {
1720 /* Without autoclear_features, we would always have to assume
1721 * that a program without persistent dirty bitmap support has
1722 * accessed this qcow2 file when opening it, and would thus
1723 * have to drop all dirty bitmaps (defeating their purpose).
1725 error_setg(errp, "Cannot store dirty bitmaps in qcow2 v2 files");
1729 if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) {
1733 FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
1734 if (bdrv_dirty_bitmap_get_persistence(bitmap)) {
1736 bitmap_directory_size +=
1737 calc_dir_entry_size(strlen(bdrv_dirty_bitmap_name(bitmap)), 0);
1741 bitmap_directory_size += calc_dir_entry_size(strlen(name), 0);
1743 if (nb_bitmaps > QCOW2_MAX_BITMAPS) {
1745 "Maximum number of persistent bitmaps is already reached");
1749 if (bitmap_directory_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) {
1750 error_setg(errp, "Not enough space in the bitmap directory");
1757 error_prepend(errp, "Can't make bitmap '%s' persistent in '%s': ",
1758 name, bdrv_get_device_or_node_name(bs));
1762 bool qcow2_supports_persistent_dirty_bitmap(BlockDriverState *bs)
1764 BDRVQcow2State *s = bs->opaque;
1766 return s->qcow_version >= 3;
1770 * Compute the space required to copy bitmaps from @in_bs.
1772 * The computation is based as if copying to a new image with the
1773 * given @cluster_size, which may differ from the cluster size in
1774 * @in_bs; in fact, @in_bs might be something other than qcow2.
1776 uint64_t qcow2_get_persistent_dirty_bitmap_size(BlockDriverState *in_bs,
1777 uint32_t cluster_size)
1779 uint64_t bitmaps_size = 0;
1780 BdrvDirtyBitmap *bm;
1781 size_t bitmap_dir_size = 0;
1783 FOR_EACH_DIRTY_BITMAP(in_bs, bm) {
1784 if (bdrv_dirty_bitmap_get_persistence(bm)) {
1785 const char *name = bdrv_dirty_bitmap_name(bm);
1786 uint32_t granularity = bdrv_dirty_bitmap_granularity(bm);
1788 get_bitmap_bytes_needed(bdrv_dirty_bitmap_size(bm),
1790 uint64_t bmclusters = DIV_ROUND_UP(bmbytes, cluster_size);
1792 /* Assume the entire bitmap is allocated */
1793 bitmaps_size += bmclusters * cluster_size;
1794 /* Also reserve space for the bitmap table entries */
1795 bitmaps_size += ROUND_UP(bmclusters * BME_TABLE_ENTRY_SIZE,
1797 /* And space for contribution to bitmap directory size */
1798 bitmap_dir_size += calc_dir_entry_size(strlen(name), 0);
1801 bitmaps_size += ROUND_UP(bitmap_dir_size, cluster_size);
1803 return bitmaps_size;