From 6997c5c32d753435bed2b89c11ff019a5581487d Mon Sep 17 00:00:00 2001
From: Derek McGowan <derek@mcgstyle.net>
Date: Wed, 22 Mar 2017 10:58:45 -0700
Subject: [PATCH] Update btrfs undo logic

Ensure undo failures are logged in a consistent way.
Remove created subvolume on commit failure on create.
Ensure that removed value get logged on delete failure.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
---
 snapshot/btrfs/btrfs.go | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/snapshot/btrfs/btrfs.go b/snapshot/btrfs/btrfs.go
index 9c9ae75..ab0904d 100644
--- a/snapshot/btrfs/btrfs.go
+++ b/snapshot/btrfs/btrfs.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/Sirupsen/logrus"
 	"github.com/docker/containerd"
 	"github.com/docker/containerd/log"
 	"github.com/docker/containerd/plugin"
@@ -138,6 +139,9 @@ func (b *Snapshotter) makeActive(ctx context.Context, key, parent string, readon
 	err = t.Commit()
 	t = nil
 	if err != nil {
+		if derr := btrfs.SubvolDelete(target); derr != nil {
+			log.G(ctx).WithError(derr).WithField("subvolume", target).Error("Failed to delete subvolume")
+		}
 		return nil, err
 	}
 
@@ -199,13 +203,14 @@ func (b *Snapshotter) Commit(ctx context.Context, name, key string) (err error)
 	t = nil
 	if err != nil {
 		if derr := btrfs.SubvolDelete(target); derr != nil {
-			log.G(ctx).WithError(derr).Error("Failed to clean up new snapshot: %v", target)
+			log.G(ctx).WithError(derr).WithField("subvolume", target).Error("Failed to delete subvolume")
 		}
 		return err
 	}
 
 	if derr := btrfs.SubvolDelete(source); derr != nil {
-		log.G(ctx).WithError(derr).Warn("Failed to clean up active snapshot: %v", source)
+		// Log as warning, only needed for cleanup, will not cause name collision
+		log.G(ctx).WithError(derr).WithField("subvolume", source).Warn("Failed to delete subvolume")
 	}
 
 	return nil
@@ -250,7 +255,7 @@ func (b *Snapshotter) Remove(ctx context.Context, key string) (err error) {
 
 		if removed != "" {
 			if derr := btrfs.SubvolDelete(removed); derr != nil {
-				log.G(ctx).WithError(derr).Warn("Failed to clean up removed snapshot: %v", removed)
+				log.G(ctx).WithError(derr).WithField("subvolume", removed).Warn("Failed to delete subvolume")
 			}
 		}
 	}()
@@ -291,9 +296,13 @@ func (b *Snapshotter) Remove(ctx context.Context, key string) (err error) {
 	if err != nil {
 		// Attempt to restore source
 		if err1 := btrfs.SubvolSnapshot(source, removed, readonly); err1 != nil {
+			log.G(ctx).WithFields(logrus.Fields{
+				logrus.ErrorKey: err1,
+				"subvolume":     source,
+				"renamed":       removed,
+			}).Error("Failed to restore subvolume from renamed")
 			// Keep removed to allow for manual restore
 			removed = ""
-			log.G(ctx).WithError(err1).Error("Failed to restore source snapshot %v from %v", source, removed)
 		}
 		return err
 	}