Commit a78a1a48 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by John Snow
Browse files

dirty-bitmap: add bdrv_dirty_bitmap_next_dirty_area 



The function alters bdrv_dirty_iter_next_area(), which is wrong and
less efficient (see further commit
"block/mirror: fix and improve do_sync_target_write" for description).

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
parent fa9c2da2

block/dirty-bitmap.c

+6 −0
Original line number Diff line number Diff line
@@ -787,6 +787,12 @@ int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset, 
    return hbitmap_next_zero(bitmap->bitmap, offset, bytes);

}



bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,

                                       uint64_t *offset, uint64_t *bytes)

{

    return hbitmap_next_dirty_area(bitmap->bitmap, offset, bytes);

}



void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,

                             HBitmap **backup, Error **errp)

{

include/block/dirty-bitmap.h

+2 −0
Original line number Diff line number Diff line
@@ -101,6 +101,8 @@ BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs, 
char *bdrv_dirty_bitmap_sha256(const BdrvDirtyBitmap *bitmap, Error **errp);

int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset,

                                    uint64_t bytes);

bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,

                                       uint64_t *offset, uint64_t *bytes);

BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs,

                                                  BdrvDirtyBitmap *bitmap,

                                                  Error **errp);

include/qemu/hbitmap.h

+16 −0
Original line number Diff line number Diff line
@@ -311,6 +311,22 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi); 
 */

int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count);



/* hbitmap_next_dirty_area:

 * @hb: The HBitmap to operate on

 * @start: in-out parameter.

 *         in: the offset to start from

 *         out: (if area found) start of found area

 * @count: in-out parameter.

 *         in: length of requested region

 *         out: length of found area

 *

 * If dirty area found within [@start, @start + @count), returns true and sets

 * @offset and @bytes appropriately. Otherwise returns false and leaves @offset

 * and @bytes unchanged.

 */

bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *start,

                             uint64_t *count);



/* hbitmap_create_meta:

 * Create a "meta" hbitmap to track dirtiness of the bits in this HBitmap.

 * The caller owns the created bitmap and must call hbitmap_free_meta(hb) to

util/hbitmap.c

+39 −0
Original line number Diff line number Diff line
@@ -246,6 +246,45 @@ int64_t hbitmap_next_zero(const HBitmap *hb, uint64_t start, uint64_t count) 
    return res;

}



bool hbitmap_next_dirty_area(const HBitmap *hb, uint64_t *start,

                             uint64_t *count)

{

    HBitmapIter hbi;

    int64_t firt_dirty_off, area_end;

    uint32_t granularity = 1UL << hb->granularity;

    uint64_t end;



    if (*start >= hb->orig_size || *count == 0) {

        return false;

    }



    end = *count > hb->orig_size - *start ? hb->orig_size : *start + *count;



    hbitmap_iter_init(&hbi, hb, *start);

    firt_dirty_off = hbitmap_iter_next(&hbi, false);



    if (firt_dirty_off < 0 || firt_dirty_off >= end) {

        return false;

    }



    if (firt_dirty_off + granularity >= end) {

        area_end = end;

    } else {

        area_end = hbitmap_next_zero(hb, firt_dirty_off + granularity,

                                     end - firt_dirty_off - granularity);

        if (area_end < 0) {

            area_end = end;

        }

    }



    if (firt_dirty_off > *start) {

        *start = firt_dirty_off;

    }

    *count = area_end - *start;



    return true;

}



bool hbitmap_empty(const HBitmap *hb)

{

    return hb->count == 0;