We actually don't restore anything just yet, so this commit message is a little off I think.
On 07/06/2018 07:36 AM, Vladimir Sementsov-Ogievskiy wrote: > Add backup parameter to bdrv_merge_dirty_bitmap() and refactor > bdrv_undo_clear_dirty_bitmap() to use it both for undo clean and merge. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> > --- > include/block/block_int.h | 2 +- > include/block/dirty-bitmap.h | 2 +- > include/qemu/hbitmap.h | 25 ++++++++++++++++--------- > block/dirty-bitmap.c | 21 ++++++++++++++++----- > blockdev.c | 4 ++-- > util/hbitmap.c | 11 ++++++++--- > 6 files changed, 44 insertions(+), 21 deletions(-) > > diff --git a/include/block/block_int.h b/include/block/block_int.h > index af71b414be..64e38b4fae 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -1144,7 +1144,7 @@ bool blk_dev_is_medium_locked(BlockBackend *blk); > void bdrv_set_dirty(BlockDriverState *bs, int64_t offset, int64_t bytes); > > void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap **out); > -void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in); > +void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup); > > void bdrv_inc_in_flight(BlockDriverState *bs); > void bdrv_dec_in_flight(BlockDriverState *bs); > diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h > index 259bd27c40..201ff7f20b 100644 > --- a/include/block/dirty-bitmap.h > +++ b/include/block/dirty-bitmap.h > @@ -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); > diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h > index ddca52c48e..a7cb780592 100644 > --- a/include/qemu/hbitmap.h > +++ b/include/qemu/hbitmap.h > @@ -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, > - * false if it was not attempted. > - * > - * Merge two bitmaps together. > - * A := A (BITOR) B. > - * B is left unmodified. > + * > + * 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); I wonder if this confuses any optimization or analysis tools. I'll assume it's safe. > + > +/** > + * hbitmap_can_merge: > + * > + * hbitmap_can_merge(a, b) && hbitmap_can_merge(a, result) is sufficient and > + * necessary for hbitmap_merge will not fail. > + * > */ > -bool hbitmap_merge(HBitmap *a, const HBitmap *b); > +bool hbitmap_can_merge(const HBitmap *a, const HBitmap *b); > > /** > * hbitmap_empty: > diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c > index 6c8761e027..8ac933cf1c 100644 > --- a/block/dirty-bitmap.c > +++ b/block/dirty-bitmap.c > @@ -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; > } > @@ -633,12 +633,12 @@ void bdrv_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, > HBitmap **out) > bdrv_dirty_bitmap_unlock(bitmap); > } > > -void bdrv_undo_clear_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *in) > +void bdrv_restore_dirty_bitmap(BdrvDirtyBitmap *bitmap, HBitmap *backup) > { > HBitmap *tmp = bitmap->bitmap; > assert(bdrv_dirty_bitmap_enabled(bitmap)); > assert(!bdrv_dirty_bitmap_readonly(bitmap)); > - bitmap->bitmap = in; > + bitmap->bitmap = backup; > hbitmap_free(tmp); > } > > @@ -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); > } > diff --git a/blockdev.c b/blockdev.c > index 902338e815..9cb29ca63e 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -2032,7 +2032,7 @@ static void > block_dirty_bitmap_clear_abort(BlkActionState *common) > common, common); > > if (state->backup) { > - bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup); > + bdrv_restore_dirty_bitmap(state->bitmap, state->backup); > } > } > > @@ -2961,7 +2961,7 @@ 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, > diff --git a/util/hbitmap.c b/util/hbitmap.c > index bcd304041a..d5aca5159f 100644 > --- a/util/hbitmap.c > +++ b/util/hbitmap.c > @@ -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)); This line might really be overkill, but I suppose it doesn't take long to check, so no harm. > > 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]; > } > } > > This patch really does two things; Refactors undo_clear and adds the new merge functionality, but not worth respinning just to separate two trivial changes. Only minor comments, so: Reviewed-by: John Snow <js...@redhat.com>