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block: Support meta dirty bitmap 

The added group of operations enables tracking of the changed bits in
the dirty bitmap.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 1476395910-8697-5-git-send-email-jsnow@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Fam Zheng 2016-10-13 17:58:24 -04:00 committed by Max Reitz
parent 4b62818a4f
commit fb933437de
2 changed files with 61 additions and 0 deletions
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52
block/dirty-bitmap.c
View File

@ -38,6 +38,7 @@
*/
struct BdrvDirtyBitmap {
HBitmap *bitmap; /* Dirty sector bitmap implementation */
HBitmap *meta; /* Meta dirty bitmap */
BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
char *name; /* Optional non-empty unique ID */
int64_t size; /* Size of the bitmap (Number of sectors) */
@ -103,6 +104,56 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
return bitmap;
}
/* bdrv_create_meta_dirty_bitmap
*
* Create a meta dirty bitmap that tracks the changes of bits in @bitmap. I.e.
* when a dirty status bit in @bitmap is changed (either from reset to set or
* the other way around), its respective meta dirty bitmap bit will be marked
* dirty as well.
*
* @bitmap: the block dirty bitmap for which to create a meta dirty bitmap.
* @chunk_size: how many bytes of bitmap data does each bit in the meta bitmap
* track.
*/
void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,
int chunk_size)
{
assert(!bitmap->meta);
bitmap->meta = hbitmap_create_meta(bitmap->bitmap,
chunk_size * BITS_PER_BYTE);
}
void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)
{
assert(bitmap->meta);
hbitmap_free_meta(bitmap->bitmap);
bitmap->meta = NULL;
}
int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap, int64_t sector,
int nb_sectors)
{
uint64_t i;
int sectors_per_bit = 1 << hbitmap_granularity(bitmap->meta);
/* To optimize: we can make hbitmap to internally check the range in a
* coarse level, or at least do it word by word. */
for (i = sector; i < sector + nb_sectors; i += sectors_per_bit) {
if (hbitmap_get(bitmap->meta, i)) {
return true;
}
}
return false;
}
void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap, int64_t sector,
int nb_sectors)
{
hbitmap_reset(bitmap->meta, sector, nb_sectors);
}
bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap)
{
return bitmap->successor;
@ -233,6 +284,7 @@ static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
assert(!bm->active_iterators);
assert(!bdrv_dirty_bitmap_frozen(bm));
assert(!bm->meta);
QLIST_REMOVE(bm, list);
hbitmap_free(bm->bitmap);
g_free(bm->name);

9
include/block/dirty-bitmap.h
View File

@ -8,6 +8,9 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
uint32_t granularity,
const char *name,
Error **errp);
void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,
int chunk_size);
void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap);
int bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap,
Error **errp);
@ -36,6 +39,12 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
int64_t cur_sector, int64_t nr_sectors);
void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
int64_t cur_sector, int64_t nr_sectors);
int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap, int64_t sector,
int nb_sectors);
void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
BdrvDirtyBitmap *bitmap, int64_t sector,
int nb_sectors);
BdrvDirtyBitmapIter *bdrv_dirty_iter_new(BdrvDirtyBitmap *bitmap,
uint64_t first_sector);
void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter);