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-rw-r--r--include/block/block.h32
1 files changed, 32 insertions, 0 deletions
diff --git a/include/block/block.h b/include/block/block.h
index 3894edda9d..6cc6c7e699 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -611,4 +611,36 @@ bool bdrv_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
*/
void bdrv_register_buf(BlockDriverState *bs, void *host, size_t size);
void bdrv_unregister_buf(BlockDriverState *bs, void *host);
+
+/**
+ *
+ * bdrv_co_copy_range:
+ *
+ * Do offloaded copy between two children. If the operation is not implemented
+ * by the driver, or if the backend storage doesn't support it, a negative
+ * error code will be returned.
+ *
+ * Note: block layer doesn't emulate or fallback to a bounce buffer approach
+ * because usually the caller shouldn't attempt offloaded copy any more (e.g.
+ * calling copy_file_range(2)) after the first error, thus it should fall back
+ * to a read+write path in the caller level.
+ *
+ * @src: Source child to copy data from
+ * @src_offset: offset in @src image to read data
+ * @dst: Destination child to copy data to
+ * @dst_offset: offset in @dst image to write data
+ * @bytes: number of bytes to copy
+ * @flags: request flags. Must be one of:
+ * 0 - actually read data from src;
+ * BDRV_REQ_ZERO_WRITE - treat the @src range as zero data and do zero
+ * write on @dst as if bdrv_co_pwrite_zeroes is
+ * called. Used to simplify caller code, or
+ * during BlockDriver.bdrv_co_copy_range_from()
+ * recursion.
+ *
+ * Returns: 0 if succeeded; negative error code if failed.
+ **/
+int coroutine_fn bdrv_co_copy_range(BdrvChild *src, uint64_t src_offset,
+ BdrvChild *dst, uint64_t dst_offset,
+ uint64_t bytes, BdrvRequestFlags flags);
#endif