diff options
Diffstat (limited to 'block/qcow2-bitmap.c')
-rw-r--r-- | block/qcow2-bitmap.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index 1cf6d2a..7bf1250 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -1755,3 +1755,39 @@ bool qcow2_supports_persistent_dirty_bitmap(BlockDriverState *bs) return s->qcow_version >= 3; } + +/* + * Compute the space required for bitmaps in @bs. + * + * The computation is based as if copying to a new image with the + * given @cluster_size, which may differ from the cluster size in @bs. + */ +uint64_t qcow2_get_persistent_dirty_bitmap_size(BlockDriverState *bs, + uint32_t cluster_size) +{ + uint64_t bitmaps_size = 0; + BdrvDirtyBitmap *bm; + size_t bitmap_dir_size = 0; + + FOR_EACH_DIRTY_BITMAP(bs, bm) { + if (bdrv_dirty_bitmap_get_persistence(bm)) { + const char *name = bdrv_dirty_bitmap_name(bm); + uint32_t granularity = bdrv_dirty_bitmap_granularity(bm); + uint64_t bmbytes = + get_bitmap_bytes_needed(bdrv_dirty_bitmap_size(bm), + granularity); + uint64_t bmclusters = DIV_ROUND_UP(bmbytes, cluster_size); + + /* Assume the entire bitmap is allocated */ + bitmaps_size += bmclusters * cluster_size; + /* Also reserve space for the bitmap table entries */ + bitmaps_size += ROUND_UP(bmclusters * sizeof(uint64_t), + cluster_size); + /* And space for contribution to bitmap directory size */ + bitmap_dir_size += calc_dir_entry_size(strlen(name), 0); + } + } + bitmaps_size += ROUND_UP(bitmap_dir_size, cluster_size); + + return bitmaps_size; +} |