block/dirty-bitmap: introduce bdrv_dirty_bitmap_status()

Add a convenient function similar with bdrv_block_status() to get
status of dirty bitmap.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220303194349.2304213-9-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/util/hbitmap.c b/util/hbitmap.c
index 305b894a63..dd0501d9a7 100644
--- a/util/hbitmap.c
+++ b/util/hbitmap.c
@@ -301,6 +301,39 @@ bool hbitmap_next_dirty_area(const HBitmap *hb, int64_t start, int64_t end,
     return true;
 }
 
+bool hbitmap_status(const HBitmap *hb, int64_t start, int64_t count,
+                    int64_t *pnum)
+{
+    int64_t next_dirty, next_zero;
+
+    assert(start >= 0);
+    assert(count > 0);
+    assert(start + count <= hb->orig_size);
+
+    next_dirty = hbitmap_next_dirty(hb, start, count);
+    if (next_dirty == -1) {
+        *pnum = count;
+        return false;
+    }
+
+    if (next_dirty > start) {
+        *pnum = next_dirty - start;
+        return false;
+    }
+
+    assert(next_dirty == start);
+
+    next_zero = hbitmap_next_zero(hb, start, count);
+    if (next_zero == -1) {
+        *pnum = count;
+        return true;
+    }
+
+    assert(next_zero > start);
+    *pnum = next_zero - start;
+    return false;
+}
+
 bool hbitmap_empty(const HBitmap *hb)
 {
     return hb->count == 0;