[v4,08/18] block/dirty-bitmap: introduce bdrv_dirty_bitmap_status()

Commit Message

Vladimir Sementsov-Ogievskiy Feb. 16, 2022, 7:46 p.m. UTC

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

Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
---
 include/block/dirty-bitmap.h |  2 ++
 include/qemu/hbitmap.h       | 12 ++++++++++++
 block/dirty-bitmap.c         |  6 ++++++
 util/hbitmap.c               | 33 +++++++++++++++++++++++++++++++++
 4 files changed, 53 insertions(+)

Comments

Hanna Czenczek Feb. 24, 2022, 12:20 p.m. UTC | #1

On 16.02.22 20:46, Vladimir Sementsov-Ogievskiy wrote:
> Add a convenient function similar with bdrv_block_status() to get
> status of dirty bitmap.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <[e-mail]>
> ---
>   include/block/dirty-bitmap.h |  2 ++
>   include/qemu/hbitmap.h       | 12 ++++++++++++
>   block/dirty-bitmap.c         |  6 ++++++
>   util/hbitmap.c               | 33 +++++++++++++++++++++++++++++++++
>   4 files changed, 53 insertions(+)

Reviewed-by: Hanna Reitz <[e-mail]>

Patch

diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index f95d350b70..6528336c4c 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -115,6 +115,8 @@  int64_t bdrv_dirty_bitmap_next_zero(BdrvDirtyBitmap *bitmap, int64_t offset,
 bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,
         int64_t start, int64_t end, int64_t max_dirty_count,
         int64_t *dirty_start, int64_t *dirty_count);
+bool bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap, int64_t offset,
+                              int64_t bytes, int64_t *count);
 BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap,
                                                   Error **errp);
 
diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h
index 5e71b6d6f7..5bd986aa44 100644
--- a/include/qemu/hbitmap.h
+++ b/include/qemu/hbitmap.h
@@ -340,6 +340,18 @@  bool hbitmap_next_dirty_area(const HBitmap *hb, int64_t start, int64_t end,
                              int64_t max_dirty_count,
                              int64_t *dirty_start, int64_t *dirty_count);
 
+/*
+ * bdrv_dirty_bitmap_status:
+ * @hb: The HBitmap to operate on
+ * @start: The bit to start from
+ * @count: Number of bits to proceed
+ * @pnum: Out-parameter. How many bits has same value starting from @start
+ *
+ * Returns true if bitmap is dirty at @start, false otherwise.
+ */
+bool hbitmap_status(const HBitmap *hb, int64_t start, int64_t count,
+                    int64_t *pnum);
+
 /**
  * hbitmap_iter_next:
  * @hbi: HBitmapIter to operate on.
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 94a0276833..08d56845ad 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -875,6 +875,12 @@  bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap *bitmap,
                                    dirty_start, dirty_count);
 }
 
+bool bdrv_dirty_bitmap_status(BdrvDirtyBitmap *bitmap, int64_t offset,
+                              int64_t bytes, int64_t *count)
+{
+    return hbitmap_status(bitmap->bitmap, offset, bytes, count);
+}
+
 /**
  * bdrv_merge_dirty_bitmap: merge src into dest.
  * Ensures permissions on bitmaps are reasonable; use for public API.
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;