storage/nfs: add timeout

NEWS

@@ -4,6 +4,8 @@ ver 0.19.7 (not yet released)
   - nfs: fix memory leak on connection failure
   - nfs: fix reconnect after mount failure
   - nfs: implement mount timeout (60 seconds)
+* storage
+  - nfs: implement I/O timeout (60 seconds)
 * playlist
   - don't skip non-existent songs in "listplaylist"
 * fix memory allocator bug on Windows

src/lib/nfs/Blocking.cxx

@@ -20,7 +20,9 @@
 #include "config.h"
 #include "Blocking.hxx"
 #include "Connection.hxx"
+#include "Domain.hxx"
 #include "event/Call.hxx"
+#include "util/Error.hxx"
 
 bool
 BlockingNfsOperation::Run(Error &_error)
@@ -31,7 +33,10 @@ BlockingNfsOperation::Run(Error &_error)
 		    [this](){ connection.AddLease(*this); });
 
 	/* wait for completion */
-	LockWaitFinished();
+	if (!LockWaitFinished()) {
+		_error.Set(nfs_domain, 0, "Timeout");
+		return false;
+	}
 
 	/* check for error */
 	if (error.IsDefined()) {

src/lib/nfs/Blocking.hxx

@@ -35,6 +35,8 @@ class NfsConnection;
  * thread, and method Run() waits for completion.
  */
 class BlockingNfsOperation : protected NfsCallback, NfsLease {
+	static constexpr unsigned timeout_ms = 60000;
+
 	Mutex mutex;
 	Cond cond;
 
@@ -52,10 +54,13 @@ public:
 	bool Run(Error &error);
 
 private:
-	void LockWaitFinished() {
+	bool LockWaitFinished() {
 		const ScopeLock protect(mutex);
 		while (!finished)
-			cond.wait(mutex);
+			if (!cond.timed_wait(mutex, timeout_ms))
+				return false;
+
+		return true;
 	}
 
 	/**