[Qemu-devel] [PATCH 5/8] block: add bdrv_load_dirty_bitmap

[Vladimir Sementsov-Ogievskiy]

The funcion loads dirty bitmap from file, using underlying driver
function.

Note: the function doesn't change BdrvDirtyBitmap.file field. This field
is only used by bdrv_store_dirty_bitmap() function and is ONLY written
by bdrv_dirty_bitmap_set_file() function.

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 block.c               | 37 +++++++++++++++++++++++++++++++++++++
 include/block/block.h |  5 +++++
 2 files changed, 42 insertions(+)

diff --git a/block.c b/block.c
index 7237b95..77419e9 100644
--- a/block.c
+++ b/block.c
@@ -5384,6 +5384,43 @@ BdrvDirtyBitmap 
*bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
     return originator;
 }
 
+BdrvDirtyBitmap *bdrv_load_dirty_bitmap(BlockDriverState *bs,
+                                        BlockDriverState *file,
+                                        int granularity,
+                                        const char *name,
+                                        Error **errp)
+{
+    BlockDriver *drv = file->drv;
+    if (!drv) {
+        return NULL;
+    }
+    if (drv->bdrv_dirty_bitmap_load) {
+        BdrvDirtyBitmap *bitmap;
+        uint64_t bitmap_size = bdrv_nb_sectors(bs);
+        uint8_t *buf = drv->bdrv_dirty_bitmap_load(file, name, bitmap_size,
+                                                   granularity);
+        if (buf == NULL) {
+            return NULL;
+        }
+
+        bitmap = bdrv_create_dirty_bitmap(bs, granularity, name, errp);
+        if (bitmap == NULL) {
+            g_free(buf);
+            return NULL;
+        }
+
+        hbitmap_restore_data(bitmap->bitmap, buf, 0, bitmap_size);
+        hbitmap_restore_finish(bitmap->bitmap);
+
+        return bitmap;
+    }
+    if (file->file)  {
+        return bdrv_load_dirty_bitmap(bs, file->file, granularity, name,
+                                      errp);
+    }
+    return NULL;
+}
+
 int bdrv_store_dirty_bitmap(BdrvDirtyBitmap *bitmap)
 {
     BlockDriverState *bs = bitmap->file;
diff --git a/include/block/block.h b/include/block/block.h
index 0dfefe3..f36557f 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -460,6 +460,11 @@ void bdrv_dirty_iter_init(BlockDriverState *bs,
                           BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
 void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
 int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
+BdrvDirtyBitmap *bdrv_load_dirty_bitmap(BlockDriverState *bs,
+                                        BlockDriverState *file,
+                                        int granularity,
+                                        const char *name,
+                                        Error **errp);
 int bdrv_store_dirty_bitmap(BdrvDirtyBitmap *bitmap);
 
 void bdrv_enable_copy_on_read(BlockDriverState *bs);
-- 
1.9.1