diff options
| -rw-r--r-- | block.c | 18 | ||||
| -rw-r--r-- | include/qemu/hbitmap.h | 10 | ||||
| -rw-r--r-- | util/hbitmap.c | 48 |
3 files changed, 76 insertions, 0 deletions
@@ -114,6 +114,7 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors); static void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors); +static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs); /* If non-zero, use only whitelisted block drivers */ static int use_bdrv_whitelist; @@ -3610,6 +3611,7 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset) ret = drv->bdrv_truncate(bs, offset); if (ret == 0) { ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS); + bdrv_dirty_bitmap_truncate(bs); if (bs->blk) { blk_dev_resize_cb(bs->blk); } @@ -5659,6 +5661,22 @@ BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs, return parent; } +/** + * Truncates _all_ bitmaps attached to a BDS. + */ +static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs) +{ + BdrvDirtyBitmap *bitmap; + uint64_t size = bdrv_nb_sectors(bs); + + QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) { + if (bdrv_dirty_bitmap_frozen(bitmap)) { + continue; + } + hbitmap_truncate(bitmap->bitmap, size); + } +} + void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap) { BdrvDirtyBitmap *bm, *next; diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h index 6cb2d0e6a7..f0a85f8649 100644 --- a/include/qemu/hbitmap.h +++ b/include/qemu/hbitmap.h @@ -65,6 +65,16 @@ struct HBitmapIter { HBitmap *hbitmap_alloc(uint64_t size, int granularity); /** + * hbitmap_truncate: + * @hb: The bitmap to change the size of. + * @size: The number of elements to change the bitmap to accommodate. + * + * truncate or grow an existing bitmap to accommodate a new number of elements. + * This may invalidate existing HBitmapIterators. + */ +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. diff --git a/util/hbitmap.c b/util/hbitmap.c index 150d6e98b7..a10c7aeeda 100644 --- a/util/hbitmap.c +++ b/util/hbitmap.c @@ -400,6 +400,54 @@ HBitmap *hbitmap_alloc(uint64_t size, int granularity) return hb; } +void hbitmap_truncate(HBitmap *hb, uint64_t size) +{ + bool shrink; + unsigned i; + uint64_t num_elements = size; + uint64_t old; + + /* Size comes in as logical elements, adjust for granularity. */ + size = (size + (1ULL << hb->granularity) - 1) >> hb->granularity; + assert(size <= ((uint64_t)1 << HBITMAP_LOG_MAX_SIZE)); + shrink = size < hb->size; + + /* bit sizes are identical; nothing to do. */ + if (size == hb->size) { + return; + } + + /* If we're losing bits, let's clear those bits before we invalidate all of + * our invariants. This helps keep the bitcount consistent, and will prevent + * us from carrying around garbage bits beyond the end of the map. + */ + if (shrink) { + /* Don't clear partial granularity groups; + * start at the first full one. */ + uint64_t start = QEMU_ALIGN_UP(num_elements, 1 << hb->granularity); + uint64_t fix_count = (hb->size << hb->granularity) - start; + + assert(fix_count); + hbitmap_reset(hb, start, fix_count); + } + + hb->size = size; + for (i = HBITMAP_LEVELS; i-- > 0; ) { + size = MAX(BITS_TO_LONGS(size), 1); + if (hb->sizes[i] == size) { + break; + } + old = hb->sizes[i]; + hb->sizes[i] = size; + hb->levels[i] = g_realloc(hb->levels[i], size * sizeof(unsigned long)); + if (!shrink) { + memset(&hb->levels[i][old], 0x00, + (size - old) * sizeof(*hb->levels[i])); + } + } +} + + /** * Given HBitmaps A and B, let A := A (BITOR) B. * Bitmap B will not be modified. |