From 1ba55a6b1b8e90fd26a3baad496c47500e8147fa Mon Sep 17 00:00:00 2001
From: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
Date: Wed, 19 Jul 2017 18:15:28 +0200
Subject: [PATCH] Don't increment the wait count if the file is closing

This prevent a deadlock if `prepareIo()` is called on a closing file as
`Done()` would never been called afterwards.

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>
---
 file.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/file.go b/file.go
index 613f31b5..9c9ee5d2 100644
--- a/file.go
+++ b/file.go
@@ -127,10 +127,10 @@ func (f *win32File) Close() error {
 // prepareIo prepares for a new IO operation.
 // The caller must call f.wg.Done() when the IO is finished, prior to Close() returning.
 func (f *win32File) prepareIo() (*ioOperation, error) {
-	f.wg.Add(1)
 	if f.closing {
 		return nil, ErrFileClosed
 	}
+	f.wg.Add(1)
 	c := &ioOperation{}
 	c.ch = make(chan ioResult)
 	return c, nil