[Qemu-devel] [PATCH 11/25] block: introduce persistent dirty bitmaps

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

New field BdrvDirtyBitmap.persistent means, that bitmap should be saved
on bdrv_close, using format driver. Format driver should maintain bitmap
storing.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
---
 block.c                      | 32 ++++++++++++++++++++++++++++++++
 block/dirty-bitmap.c         | 26 ++++++++++++++++++++++++++
 block/qcow2-bitmap.c         |  1 +
 include/block/block.h        |  1 +
 include/block/block_int.h    |  2 ++
 include/block/dirty-bitmap.h |  6 ++++++
 6 files changed, 68 insertions(+)

diff --git a/block.c b/block.c
index 56f030c..970e4ca 100644
--- a/block.c
+++ b/block.c
@@ -2321,6 +2321,7 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state)
 static void bdrv_close(BlockDriverState *bs)
 {
     BdrvAioNotifier *ban, *ban_next;
+    Error *local_err = NULL;
 
     assert(!bs->job);
     assert(!bs->refcnt);
@@ -2329,6 +2330,12 @@ static void bdrv_close(BlockDriverState *bs)
     bdrv_flush(bs);
     bdrv_drain(bs); /* in case flush left pending I/O */
 
+    bdrv_store_persistent_dirty_bitmaps(bs, &local_err);
+    if (local_err != NULL) {
+        error_report_err(local_err);
+        error_report("Persistent bitmaps are lost for node '%s'",
+                     bdrv_get_device_or_node_name(bs));
+    }
     bdrv_release_named_dirty_bitmaps(bs);
     assert(QLIST_EMPTY(&bs->dirty_bitmaps));
 
@@ -4107,3 +4114,28 @@ void bdrv_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp)
         bs->drv->bdrv_load_autoloading_dirty_bitmaps(bs, errp);
     }
 }
+
+void bdrv_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp)
+{
+    BlockDriver *drv = bs->drv;
+
+    if (!bdrv_has_persistent_bitmaps(bs)) {
+        return;
+    }
+
+    if (!drv) {
+        error_setg_errno(errp, ENOMEDIUM,
+                         "Can't store persistent bitmaps to %s",
+                         bdrv_get_device_or_node_name(bs));
+        return;
+    }
+
+    if (!drv->bdrv_store_persistent_dirty_bitmaps) {
+        error_setg_errno(errp, ENOTSUP,
+                         "Can't store persistent bitmaps to %s",
+                         bdrv_get_device_or_node_name(bs));
+        return;
+    }
+
+    drv->bdrv_store_persistent_dirty_bitmaps(bs, errp);
+}
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index a9dfce8..d2fbf55 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -44,6 +44,7 @@ struct BdrvDirtyBitmap {
     int64_t size;               /* Size of the bitmap (Number of sectors) */
     bool disabled;              /* Bitmap is read-only */
     int active_iterators;       /* How many iterators are active */
+    bool persistent;            /* bitmap must be saved to owner disk image */
     bool autoload;              /* For persistent bitmaps: bitmap must be
                                    autoloaded on image opening */
     QLIST_ENTRY(BdrvDirtyBitmap) list;
@@ -72,6 +73,7 @@ void bdrv_dirty_bitmap_make_anon(BdrvDirtyBitmap *bitmap)
     assert(!bdrv_dirty_bitmap_frozen(bitmap));
     g_free(bitmap->name);
     bitmap->name = NULL;
+    bitmap->persistent = false;
     bitmap->autoload = false;
 }
 
@@ -241,6 +243,8 @@ BdrvDirtyBitmap *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs,
     bitmap->name = NULL;
     successor->name = name;
     bitmap->successor = NULL;
+    successor->persistent = bitmap->persistent;
+    bitmap->persistent = false;
     successor->autoload = bitmap->autoload;
     bitmap->autoload = false;
     bdrv_release_dirty_bitmap(bs, bitmap);
@@ -555,3 +559,25 @@ bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap)
 {
     return bitmap->autoload;
 }
+
+void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap, bool persistent)
+{
+    bitmap->persistent = persistent;
+}
+
+bool bdrv_dirty_bitmap_get_persistance(BdrvDirtyBitmap *bitmap)
+{
+    return bitmap->persistent;
+}
+
+bool bdrv_has_persistent_bitmaps(BlockDriverState *bs)
+{
+    BdrvDirtyBitmap *bm;
+    QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
+        if (bm->persistent) {
+            return true;
+        }
+    }
+
+    return false;
+}
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index f1ca799..1b5ae2d 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -698,6 +698,7 @@ void qcow2_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp)
                 goto fail;
             }
 
+            bdrv_dirty_bitmap_set_persistance(bitmap, true);
             bdrv_dirty_bitmap_set_autoload(bitmap, true);
             bm->flags |= BME_FLAG_IN_USE;
             created_dirty_bitmaps =
diff --git a/include/block/block.h b/include/block/block.h
index 154ac7f..0a20d68 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -552,5 +552,6 @@ void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
 void bdrv_del_child(BlockDriverState *parent, BdrvChild *child, Error **errp);
 
 void bdrv_load_autoloading_dirty_bitmaps(BlockDriverState *bs, Error **errp);
+void bdrv_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 
 #endif
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 6b2b50c..c3505da 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -322,6 +322,8 @@ struct BlockDriver {
 
     void (*bdrv_load_autoloading_dirty_bitmaps)(BlockDriverState *bs,
                                                 Error **errp);
+    void (*bdrv_store_persistent_dirty_bitmaps)(BlockDriverState *bs,
+                                                Error **errp);
 
     QLIST_ENTRY(BlockDriver) list;
 };
diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
index 45a389a..8dbd16b 100644
--- a/include/block/dirty-bitmap.h
+++ b/include/block/dirty-bitmap.h
@@ -77,4 +77,10 @@ void bdrv_dirty_bitmap_deserialize_finish(BdrvDirtyBitmap *bitmap);
 
 void bdrv_dirty_bitmap_set_autoload(BdrvDirtyBitmap *bitmap, bool autoload);
 bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap);
+void bdrv_dirty_bitmap_set_persistance(BdrvDirtyBitmap *bitmap,
+                                                bool persistent);
+bool bdrv_dirty_bitmap_get_persistance(BdrvDirtyBitmap *bitmap);
+
+bool bdrv_has_persistent_bitmaps(BlockDriverState *bs);
+
 #endif
-- 
1.8.3.1