From ce5c9502aa374b55ce73bea3eea33645a306e9c4 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Wed, 25 Oct 2017 18:05:09 +0100
Subject: Implement background (file) writes

---
 netfs/fuse/fuseApp.h     |  4 ++++
 netfs/fuse/fuseFiles.cpp | 53 +++++++++++++++++++++++++++++++++++++++++-------
 2 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/netfs/fuse/fuseApp.h b/netfs/fuse/fuseApp.h
index a15d150..c37ba6d 100644
--- a/netfs/fuse/fuseApp.h
+++ b/netfs/fuse/fuseApp.h
@@ -32,9 +32,13 @@ namespace NetFS {
 				public:
 					OpenFile(FilePrx remote, const std::string & path, int flags);
 
+					void flush();
+					void wait() const;
+
 					FilePrx remote;
 					const std::string path;
 					const int flags;
+					std::list<Ice::AsyncResultPtr> bg;
 			};
 			typedef IceUtil::Handle<OpenFile> OpenFilePtr;
 			typedef std::map<int, OpenFilePtr> OpenFiles;
diff --git a/netfs/fuse/fuseFiles.cpp b/netfs/fuse/fuseFiles.cpp
index 5268f4a..e31b4db 100644
--- a/netfs/fuse/fuseFiles.cpp
+++ b/netfs/fuse/fuseFiles.cpp
@@ -36,6 +36,25 @@ NetFS::FuseApp::clearFileProxy(uint64_t localID)
 	openFiles.erase(localID);
 }
 
+void
+NetFS::FuseApp::OpenFile::wait() const
+{
+	for (const auto & w : bg) {
+		w->waitForCompleted();
+	}
+}
+
+void
+NetFS::FuseApp::OpenFile::flush()
+{
+	while (!bg.empty()) {
+		auto w = bg.front();
+		bg.pop_front();
+		// bg operations are void, so no need to actually get the return value
+		w->throwLocalException();
+	}
+}
+
 int
 NetFS::FuseApp::open(const char * p, struct fuse_file_info * fi)
 {
@@ -66,12 +85,19 @@ int
 NetFS::FuseApp::release(const char *, struct fuse_file_info * fi)
 {
 	try {
-		auto remote = getFileProxy(fi->fh)->remote;
+		auto of = getFileProxy(fi->fh);
+		auto remote = of->remote;
+		try {
+			of->flush();
+		}
+		catch (NetFS::SystemError & e) {
+		}
 		remote->close();
 		clearFileProxy(fi->fh);
 		return 0;
 	}
 	catch (NetFS::SystemError & e) {
+		clearFileProxy(fi->fh);
 		return -e.syserrno;
 	}
 }
@@ -80,7 +106,7 @@ int
 NetFS::FuseApp::flush(const char *, struct fuse_file_info * fi)
 {
 	try {
-		(void)fi;
+		getFileProxy(fi->fh)->flush();
 		return 0;
 	}
 	catch (NetFS::SystemError & e) {
@@ -92,7 +118,9 @@ int
 NetFS::FuseApp::read(const char *, char * buf, size_t s, off_t o, struct fuse_file_info * fi)
 {
 	try {
-		auto remote = getFileProxy(fi->fh)->remote;
+		auto of = getFileProxy(fi->fh);
+		of->wait();
+		auto remote = of->remote;
 		NetFS::Buffer data = remote->read(o, s);
 		memcpy(buf, &data.front(), data.size());
 		return data.size();
@@ -106,8 +134,15 @@ int
 NetFS::FuseApp::write(const char *, const char * buf, size_t s, off_t o, struct fuse_file_info * fi)
 {
 	try {
-		auto remote = getFileProxy(fi->fh)->remote;
-		remote->write(o, s, NetFS::Buffer(buf, buf + s));
+		auto of = getFileProxy(fi->fh);
+		auto remote = of->remote;
+		auto r = remote->begin_write(o, s, NetFS::Buffer(buf, buf + s));
+		if (fcr->Async) {
+			of->bg.push_back(r);
+		}
+		else {
+			r->throwLocalException();
+		}
 		return s;
 	}
 	catch (NetFS::SystemError & e) {
@@ -131,7 +166,9 @@ int
 NetFS::FuseApp::ftruncate(const char *, off_t o, fuse_file_info * fi)
 {
 	try {
-		auto remote = getFileProxy(fi->fh)->remote;
+		auto of = getFileProxy(fi->fh);
+		of->wait();
+		auto remote = of->remote;
 		remote->ftruncate(reqEnv(), o);
 		return 0;
 	}
@@ -144,7 +181,9 @@ int
 NetFS::FuseApp::fgetattr(const char *, struct stat * s, fuse_file_info * fi)
 {
 	try {
-		auto remote = getFileProxy(fi->fh)->remote;
+		auto of = getFileProxy(fi->fh);
+		of->wait();
+		auto remote = of->remote;
 		*s = converter.convert(remote->fgetattr(reqEnv()));
 		return 0;
 	}
-- 
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