Commit fa000f2f authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by John Snow
Browse files

dirty-bitmap: make it possible to restore bitmap after merge 



Add backup parameter to bdrv_merge_dirty_bitmap() to be used then with
bdrv_restore_dirty_bitmap() if it needed to restore the bitmap after
merge operation.

This is needed to implement bitmap merge transaction action in further
commit.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarJohn Snow <jsnow@redhat.com>
parent 56bd6624

block/dirty-bitmap.c

+14 −3
Original line number Diff line number Diff line
@@ -314,7 +314,7 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs, 
        return NULL;

    }



    if (!hbitmap_merge(parent->bitmap, successor->bitmap)) {

    if (!hbitmap_merge(parent->bitmap, successor->bitmap, parent->bitmap)) {

        error_setg(errp, "Merging of parent and successor bitmap failed");

        return NULL;

    }
@@ -791,8 +791,10 @@ int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, uint64_t offset) 
}



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

                             Error **errp)

                             HBitmap **backup, Error **errp)

{

    bool ret;



    /* only bitmaps from one bds are supported */

    assert(dest->mutex == src->mutex);
@@ -810,11 +812,20 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src, 
        goto out;

    }



    if (!hbitmap_merge(dest->bitmap, src->bitmap)) {

    if (!hbitmap_can_merge(dest->bitmap, src->bitmap)) {

        error_setg(errp, "Bitmaps are incompatible and can't be merged");

        goto out;

    }



    if (backup) {

        *backup = dest->bitmap;

        dest->bitmap = hbitmap_alloc(dest->size, hbitmap_granularity(*backup));

        ret = hbitmap_merge(*backup, src->bitmap, dest->bitmap);

    } else {

        ret = hbitmap_merge(dest->bitmap, src->bitmap, dest->bitmap);

    }

    assert(ret);



out:

    qemu_mutex_unlock(dest->mutex);

}

blockdev.c

+1 −1
Original line number Diff line number Diff line
@@ -2968,7 +2968,7 @@ void qmp_x_block_dirty_bitmap_merge(const char *node, const char *dst_name, 
        return;

    }



    bdrv_merge_dirty_bitmap(dst, src, errp);

    bdrv_merge_dirty_bitmap(dst, src, NULL, errp);

}



BlockDirtyBitmapSha256 *qmp_x_debug_block_dirty_bitmap_sha256(const char *node,

include/block/dirty-bitmap.h

+1 −1
Original line number Diff line number Diff line
@@ -71,7 +71,7 @@ void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap, 
                                       bool persistent);

void bdrv_dirty_bitmap_set_qmp_locked(BdrvDirtyBitmap *bitmap, bool qmp_locked);

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

                             Error **errp);

                             HBitmap **backup, Error **errp);



/* Functions that require manual locking.  */

void bdrv_dirty_bitmap_lock(BdrvDirtyBitmap *bitmap);

include/qemu/hbitmap.h

+16 −9
Original line number Diff line number Diff line
@@ -73,16 +73,23 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size); 


/**

 * hbitmap_merge:

 * @a: The bitmap to store the result in.

 * @b: The bitmap to merge into @a.

 * @return true if the merge was successful,

 *

 * Store result of merging @a and @b into @result.

 * @result is allowed to be equal to @a or @b.

 *

 * Return true if the merge was successful,

 *        false if it was not attempted.

 */

bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result);



/**

 * hbitmap_can_merge:

 *

 * hbitmap_can_merge(a, b) && hbitmap_can_merge(a, result) is sufficient and

 * necessary for hbitmap_merge will not fail.

 *

 * Merge two bitmaps together.

 * A := A (BITOR) B.

 * B is left unmodified.

 */

bool hbitmap_merge(HBitmap *a, const HBitmap *b);

bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b);



/**

 * hbitmap_empty:

util/hbitmap.c

+8 −3
Original line number Diff line number Diff line
@@ -723,6 +723,10 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size) 
    }

}



bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b)

{

    return (a->size == b->size) && (a->granularity == b->granularity);

}



/**

 * Given HBitmaps A and B, let A := A (BITOR) B.
@@ -731,14 +735,15 @@ void hbitmap_truncate(HBitmap *hb, uint64_t size) 
 * @return true if the merge was successful,

 *         false if it was not attempted.

 */

bool hbitmap_merge(HBitmap *a, const HBitmap *b)

bool hbitmap_merge(const HBitmap *a, const HBitmap *b, HBitmap *result)

{

    int i;

    uint64_t j;



    if ((a->size != b->size) || (a->granularity != b->granularity)) {

    if (!hbitmap_can_merge(a, b) || !hbitmap_can_merge(a, result)) {

        return false;

    }

    assert(hbitmap_can_merge(b, result));



    if (hbitmap_count(b) == 0) {

        return true;
@@ -750,7 +755,7 @@ bool hbitmap_merge(HBitmap *a, const HBitmap *b) 
     */

    for (i = HBITMAP_LEVELS - 1; i >= 0; i--) {

        for (j = 0; j < a->sizes[i]; j++) {

            a->levels[i][j] |= b->levels[i][j];

            result->levels[i][j] = a->levels[i][j] | b->levels[i][j];

        }

    }