Added method vfs_asynchronous_write_pages(), which, unsurprisingly,

writes the given page iovecs asynchronously. The new class
AsyncIOCallback is used to inform the caller when the request has been
finished.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@27055 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/vfs.h

@@ -251,10 +251,44 @@ extern status_t		_user_socketpair(int family, int type, int protocol,
 extern status_t		_user_get_next_socket_stat(int family, uint32 *cookie,
 						struct net_stat *stat);
 
-/* vfs entry points... */
-
 #ifdef __cplusplus
 }
 #endif
 
+
+#ifdef __cplusplus
+
+class AsyncIOCallback {
+public:
+	virtual						~AsyncIOCallback();
+
+	virtual	void				IOFinished(status_t status,
+									bool partialTransfer,
+									size_t bytesTransferred) = 0;
+
+			void				operator delete(void* address, size_t size);
+
+	static	status_t 			IORequestCallback(void* data,
+									io_request* request, status_t status,
+									bool partialTransfer,
+									size_t transferEndOffset);
+};
+
+
+class StackableAsyncIOCallback : public AsyncIOCallback {
+public:
+								StackableAsyncIOCallback(AsyncIOCallback* next);
+
+protected:
+			AsyncIOCallback*	fNextCallback;
+};
+
+
+status_t vfs_asynchronous_write_pages(struct vnode* vnode, void* cookie,
+			off_t pos, const iovec* vecs, size_t count, size_t numBytes,
+			uint32 flags, AsyncIOCallback* callback);
+
+
+#endif	// __cplusplus
+
 #endif	/* _KERNEL_VFS_H */

src/system/kernel/fs/vfs_request_io.cpp

@@ -14,6 +14,44 @@
 #endif
 
 
+// #pragma mark - AsyncIOCallback
+
+
+AsyncIOCallback::~AsyncIOCallback()
+{
+}
+
+
+void
+AsyncIOCallback::operator delete(void* address, size_t size)
+{
+	io_request_free(address);
+}
+
+
+/* static */ status_t
+AsyncIOCallback::IORequestCallback(void* data, io_request* request,
+	status_t status, bool partialTransfer, size_t transferEndOffset)
+{
+	((AsyncIOCallback*)data)->IOFinished(status, partialTransfer,
+		transferEndOffset);
+	return B_OK;
+}
+
+
+// #pragma mark - StackableAsyncIOCallback
+
+
+StackableAsyncIOCallback::StackableAsyncIOCallback(AsyncIOCallback* next)
+	:
+	fNextCallback(next)
+{
+}
+
+
+// #pragma mark -
+
+
 struct iterative_io_cookie {
 	struct vnode*					vnode;
 	file_descriptor*				descriptor;
@@ -379,6 +417,32 @@ vfs_synchronous_io(io_request* request,
 }
 
 
+status_t
+vfs_asynchronous_write_pages(struct vnode* vnode, void* cookie, off_t pos,
+	const iovec* vecs, size_t count, size_t numBytes, uint32 flags,
+	AsyncIOCallback* callback)
+{
+	IORequest* request = IORequest::Create((flags & B_VIP_IO_REQUEST) != 0);
+	if (request == NULL) {
+		callback->IOFinished(B_NO_MEMORY, true, 0);
+		return B_NO_MEMORY;
+	}
+
+	status_t status = request->Init(pos, vecs, count, numBytes, true,
+		flags | B_DELETE_IO_REQUEST);
+	if (status != B_OK) {
+		delete request;
+		callback->IOFinished(status, true, 0);
+		return status;
+	}
+
+	request->SetFinishedCallback(&AsyncIOCallback::IORequestCallback,
+		callback);
+
+	return vfs_vnode_io(vnode, cookie, request);
+}
+
+
 // #pragma mark - public API