Meta bitmap is a 'dirty bitmap' for the BdrvDirtyBitmap. It tracks changes (set/unset) of this BdrvDirtyBitmap. It is needed for live migration of block dirty bitmaps.
Reviewed-by: John Snow <js...@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- block.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ include/block/block.h | 7 +++++++ 2 files changed, 51 insertions(+) diff --git a/block.c b/block.c index 1171dbb..05307bc 100644 --- a/block.c +++ b/block.c @@ -61,9 +61,15 @@ * (3) successor is set: frozen mode. * A frozen bitmap cannot be renamed, deleted, anonymized, cleared, set, * or enabled. A frozen bitmap can only abdicate() or reclaim(). + * + * Meta bitmap: + * Meta bitmap is a 'dirty bitmap' for the BdrvDirtyBitmap. It tracks changes + * (set/unset) of this BdrvDirtyBitmap. It is needed for live migration of + * block dirty bitmaps. */ struct BdrvDirtyBitmap { HBitmap *bitmap; /* Dirty sector bitmap implementation */ + HBitmap *meta_bitmap; /* Meta 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) */ @@ -3145,6 +3151,35 @@ void bdrv_dirty_bitmap_make_anon(BdrvDirtyBitmap *bitmap) bitmap->name = NULL; } +HBitmap *bdrv_create_meta_bitmap(BdrvDirtyBitmap *bitmap, + uint64_t chunk_size) +{ + uint64_t sector_granularity; + + assert((chunk_size & (chunk_size - 1)) == 0); + + /* one chunk is corresponding to one bit of the meta bitmap, and each bit + * of the chunk is corresponding to 'bdrv_dirty_bitmap_granularity(bitmap)' + * bytes of the node */ + sector_granularity = + (chunk_size * 8 * bdrv_dirty_bitmap_granularity(bitmap)) + >> BDRV_SECTOR_BITS; + assert(sector_granularity); + + bitmap->meta_bitmap = + hbitmap_alloc(bitmap->size, ctz64(sector_granularity)); + + return bitmap->meta_bitmap; +} + +void bdrv_release_meta_bitmap(BdrvDirtyBitmap *bitmap) +{ + if (bitmap->meta_bitmap) { + hbitmap_free(bitmap->meta_bitmap); + bitmap->meta_bitmap = NULL; + } +} + BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, uint32_t granularity, const char *name, @@ -3305,6 +3340,9 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) assert(!bdrv_dirty_bitmap_frozen(bm)); QLIST_REMOVE(bitmap, list); hbitmap_free(bitmap->bitmap); + if (bitmap->meta_bitmap) { + hbitmap_free(bitmap->meta_bitmap); + } g_free(bitmap->name); g_free(bitmap); return; @@ -3390,6 +3428,9 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap, { assert(bdrv_dirty_bitmap_enabled(bitmap)); hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors); + if (bitmap->meta_bitmap) { + hbitmap_set(bitmap->meta_bitmap, cur_sector, nr_sectors); + } } void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap, @@ -3397,6 +3438,9 @@ void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap, { assert(bdrv_dirty_bitmap_enabled(bitmap)); hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors); + if (bitmap->meta_bitmap) { + hbitmap_set(bitmap->meta_bitmap, cur_sector, nr_sectors); + } } void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap) diff --git a/include/block/block.h b/include/block/block.h index 5b9c2d6..7deb8e8 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -5,6 +5,7 @@ #include "qemu-common.h" #include "qemu/option.h" #include "qemu/coroutine.h" +#include "qemu/hbitmap.h" #include "block/accounting.h" #include "qapi/qmp/qobject.h" #include "qapi-types.h" @@ -511,6 +512,12 @@ void bdrv_dirty_bitmap_deserialize_zeroes(BdrvDirtyBitmap *bitmap, uint64_t start, uint64_t count); void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap); +/* chunk size here is number of bytes of the @bitmap data per one bit of the + * meta bitmap being created */ +HBitmap *bdrv_create_meta_bitmap(BdrvDirtyBitmap *bitmap, + uint64_t granularity); +void bdrv_release_meta_bitmap(BdrvDirtyBitmap *bitmap); + void bdrv_enable_copy_on_read(BlockDriverState *bs); void bdrv_disable_copy_on_read(BlockDriverState *bs); -- 2.1.4