From 47b17dc1bbf56e956080f3f0e8b2fb9c2d49af7a Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Thu, 25 Jun 2020 14:14:44 +0100
Subject: [PATCH] b2: cancel in progress multipart uploads and copies on rclone
 exit #4300

---
 backend/b2/upload.go | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/backend/b2/upload.go b/backend/b2/upload.go
index bc179c714..f10b0e780 100644
--- a/backend/b2/upload.go
+++ b/backend/b2/upload.go
@@ -20,6 +20,7 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/accounting"
 	"github.com/rclone/rclone/fs/hash"
+	"github.com/rclone/rclone/lib/atexit"
 	"github.com/rclone/rclone/lib/rest"
 	"golang.org/x/sync/errgroup"
 )
@@ -330,6 +331,7 @@ func (up *largeUpload) finish(ctx context.Context) error {
 
 // cancel aborts the large upload
 func (up *largeUpload) cancel(ctx context.Context) error {
+	fs.Debugf(up.o, "Cancelling large file %s", up.what)
 	opts := rest.Opts{
 		Method: "POST",
 		Path:   "/b2_cancel_large_file",
@@ -342,28 +344,19 @@ func (up *largeUpload) cancel(ctx context.Context) error {
 		resp, err := up.f.srv.CallJSON(ctx, &opts, &request, &response)
 		return up.f.shouldRetry(ctx, resp, err)
 	})
+	if err != nil {
+		fs.Errorf(up.o, "Failed to cancel large file %s: %v", up.what, err)
+	}
 	return err
 }
 
-// If the error pointer is not nil then cancel the transfer
-func (up *largeUpload) cancelOnError(ctx context.Context, err *error) {
-	if *err == nil {
-		return
-	}
-	fs.Debugf(up.o, "Cancelling large file %s due to error: %v", up.what, *err)
-	cancelErr := up.cancel(ctx)
-	if cancelErr != nil {
-		fs.Errorf(up.o, "Failed to cancel large file %s: %v", up.what, cancelErr)
-	}
-}
-
 // Stream uploads the chunks from the input, starting with a required initial
 // chunk. Assumes the file size is unknown and will upload until the input
 // reaches EOF.
 //
 // Note that initialUploadBlock must be returned to f.putBuf()
 func (up *largeUpload) Stream(ctx context.Context, initialUploadBlock []byte) (err error) {
-	defer up.cancelOnError(ctx, &err)
+	defer atexit.OnError(&err, func() { _ = up.cancel(ctx) })()
 	fs.Debugf(up.o, "Starting streaming of large file (id %q)", up.id)
 	var (
 		g, gCtx      = errgroup.WithContext(ctx)
@@ -434,7 +427,7 @@ func (up *largeUpload) Stream(ctx context.Context, initialUploadBlock []byte) (e
 
 // Upload uploads the chunks from the input
 func (up *largeUpload) Upload(ctx context.Context) (err error) {
-	defer up.cancelOnError(ctx, &err)
+	defer atexit.OnError(&err, func() { _ = up.cancel(ctx) })()
 	fs.Debugf(up.o, "Starting %s of large file in %d chunks (id %q)", up.what, up.parts, up.id)
 	var (
 		g, gCtx   = errgroup.WithContext(ctx)