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, 96 insertions, 0 deletions

diff --git a/include/block/block-copy.h b/include/block/block-copy.h
new file mode 100644
index 000000000..99370fa38
--- /dev/null
+++ b/include/block/block-copy.h
@@ -0,0 +1,96 @@
+/*
+ * block_copy API
+ *
+ * Copyright (C) 2013 Proxmox Server Solutions
+ * Copyright (c) 2019 Virtuozzo International GmbH.
+ *
+ * Authors:
+ *  Dietmar Maurer (dietmar@proxmox.com)
+ *  Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef BLOCK_COPY_H
+#define BLOCK_COPY_H
+
+#include "block/block.h"
+#include "qemu/co-shared-resource.h"
+
+/* All APIs are thread-safe */
+
+typedef void (*BlockCopyAsyncCallbackFunc)(void *opaque);
+typedef struct BlockCopyState BlockCopyState;
+typedef struct BlockCopyCallState BlockCopyCallState;
+
+BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
+                                     Error **errp);
+
+/* Function should be called prior any actual copy request */
+void block_copy_set_copy_opts(BlockCopyState *s, bool use_copy_range,
+                              bool compress);
+void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm);
+
+void block_copy_state_free(BlockCopyState *s);
+
+int64_t block_copy_reset_unallocated(BlockCopyState *s,
+                                     int64_t offset, int64_t *count);
+
+int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
+                            bool ignore_ratelimit);
+
+/*
+ * Run block-copy in a coroutine, create corresponding BlockCopyCallState
+ * object and return pointer to it. Never returns NULL.
+ *
+ * Caller is responsible to call block_copy_call_free() to free
+ * BlockCopyCallState object.
+ *
+ * @max_workers means maximum of parallel coroutines to execute sub-requests,
+ * must be > 0.
+ *
+ * @max_chunk means maximum length for one IO operation. Zero means unlimited.
+ */
+BlockCopyCallState *block_copy_async(BlockCopyState *s,
+                                     int64_t offset, int64_t bytes,
+                                     int max_workers, int64_t max_chunk,
+                                     BlockCopyAsyncCallbackFunc cb,
+                                     void *cb_opaque);
+
+/*
+ * Free finished BlockCopyCallState. Trying to free running
+ * block-copy will crash.
+ */
+void block_copy_call_free(BlockCopyCallState *call_state);
+
+/*
+ * Note, that block-copy call is marked finished prior to calling
+ * the callback.
+ */
+bool block_copy_call_finished(BlockCopyCallState *call_state);
+bool block_copy_call_succeeded(BlockCopyCallState *call_state);
+bool block_copy_call_failed(BlockCopyCallState *call_state);
+bool block_copy_call_cancelled(BlockCopyCallState *call_state);
+int block_copy_call_status(BlockCopyCallState *call_state, bool *error_is_read);
+
+void block_copy_set_speed(BlockCopyState *s, uint64_t speed);
+void block_copy_kick(BlockCopyCallState *call_state);
+
+/*
+ * Cancel running block-copy call.
+ *
+ * Cancel leaves block-copy state valid: dirty bits are correct and you may use
+ * cancel + <run block_copy with same parameters> to emulate pause/resume.
+ *
+ * Note also, that the cancel is async: it only marks block-copy call to be
+ * cancelled. So, the call may be cancelled (block_copy_call_cancelled() reports
+ * true) but not yet finished (block_copy_call_finished() reports false).
+ */
+void block_copy_call_cancel(BlockCopyCallState *call_state);
+
+BdrvDirtyBitmap *block_copy_dirty_bitmap(BlockCopyState *s);
+int64_t block_copy_cluster_size(BlockCopyState *s);
+void block_copy_set_skip_unallocated(BlockCopyState *s, bool skip);
+
+#endif /* BLOCK_COPY_H */