Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 39 insertions, 0 deletions

diff --git a/block/copy-before-write.h b/block/copy-before-write.h
new file mode 100644
index 000000000..51847e711
--- /dev/null
+++ b/block/copy-before-write.h
@@ -0,0 +1,39 @@
+/*
+ * copy-before-write filter driver
+ *
+ * The driver performs Copy-Before-Write (CBW) operation: it is injected above
+ * some node, and before each write it copies _old_ data to the target node.
+ *
+ * Copyright (c) 2018-2021 Virtuozzo International GmbH.
+ *
+ * Author:
+ *  Sementsov-Ogievskiy Vladimir <vsementsov@virtuozzo.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef COPY_BEFORE_WRITE_H
+#define COPY_BEFORE_WRITE_H
+
+#include "block/block_int.h"
+#include "block/block-copy.h"
+
+BlockDriverState *bdrv_cbw_append(BlockDriverState *source,
+                                  BlockDriverState *target,
+                                  const char *filter_node_name,
+                                  BlockCopyState **bcs,
+                                  Error **errp);
+void bdrv_cbw_drop(BlockDriverState *bs);
+
+#endif /* COPY_BEFORE_WRITE_H */