From 65665ab807513547062244bd57eebe0f94ab12d0 Mon Sep 17 00:00:00 2001
From: Daniel Nephin <dnephin@gmail.com>
Date: Thu, 7 Dec 2017 16:03:00 -0500
Subject: [PATCH] Always Cancel before Close

Document this contract.

Signed-off-by: Daniel Nephin <dnephin@gmail.com>
---
 cio/io.go  | 7 ++++---
 process.go | 1 +
 task.go    | 1 +
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/cio/io.go b/cio/io.go
index 25e398147..c5e112d9c 100644
--- a/cio/io.go
+++ b/cio/io.go
@@ -24,11 +24,12 @@ type Config struct {
 type IO interface {
 	// Config returns the IO configuration.
 	Config() Config
-	// Cancel aborts all current io operations
+	// Cancel aborts all current io operations.
 	Cancel()
-	// Wait blocks until all io copy operations have completed
+	// Wait blocks until all io copy operations have completed.
 	Wait()
-	// Close cleans up all open io resources
+	// Close cleans up all open io resources. Cancel() is always called before
+	// Close()
 	Close() error
 }
 
diff --git a/process.go b/process.go
index ad1a2a1f4..32049cf07 100644
--- a/process.go
+++ b/process.go
@@ -191,6 +191,7 @@ func (p *process) Delete(ctx context.Context, opts ...ProcessDeleteOpts) (*ExitS
 		return nil, errdefs.FromGRPC(err)
 	}
 	if p.io != nil {
+		p.io.Cancel()
 		p.io.Wait()
 		p.io.Close()
 	}
diff --git a/task.go b/task.go
index 8d256834f..28f49fa6c 100644
--- a/task.go
+++ b/task.go
@@ -163,6 +163,7 @@ func (t *task) Start(ctx context.Context) error {
 		ContainerID: t.id,
 	})
 	if err != nil {
+		t.io.Cancel()
 		t.io.Close()
 		return errdefs.FromGRPC(err)
 	}