1 files changed, 83 insertions, 0 deletions
diff --git a/volume/store/restore.go b/volume/store/restore.go
new file mode 100644
index 0000000..c0c5b51
--- /dev/null
+++ b/volume/store/restore.go
@@ -0,0 +1,83 @@
+package store
+
+import (
+	"sync"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/boltdb/bolt"
+	"github.com/docker/docker/volume"
+	"github.com/docker/docker/volume/drivers"
+)
+
+// restore is called when a new volume store is created.
+// It's primary purpose is to ensure that all drivers' refcounts are set based
+// on known volumes after a restart.
+// This only attempts to track volumes that are actually stored in the on-disk db.
+// It does not probe the available drivers to find anything that may have been added
+// out of band.
+func (s *VolumeStore) restore() {
+	var ls []volumeMetadata
+	s.db.View(func(tx *bolt.Tx) error {
+		ls = listMeta(tx)
+		return nil
+	})
+
+	chRemove := make(chan *volumeMetadata, len(ls))
+	var wg sync.WaitGroup
+	for _, meta := range ls {
+		wg.Add(1)
+		// this is potentially a very slow operation, so do it in a goroutine
+		go func(meta volumeMetadata) {
+			defer wg.Done()
+
+			var v volume.Volume
+			var err error
+			if meta.Driver != "" {
+				v, err = lookupVolume(meta.Driver, meta.Name)
+				if err != nil && err != errNoSuchVolume {
+					logrus.WithError(err).WithField("driver", meta.Driver).WithField("volume", meta.Name).Warn("Error restoring volume")
+					return
+				}
+				if v == nil {
+					// doesn't exist in the driver, remove it from the db
+					chRemove <- &meta
+					return
+				}
+			} else {
+				v, err = s.getVolume(meta.Name)
+				if err != nil {
+					if err == errNoSuchVolume {
+						chRemove <- &meta
+					}
+					return
+				}
+
+				meta.Driver = v.DriverName()
+				if err := s.setMeta(v.Name(), meta); err != nil {
+					logrus.WithError(err).WithField("driver", meta.Driver).WithField("volume", v.Name()).Warn("Error updating volume metadata on restore")
+				}
+			}
+
+			// increment driver refcount
+			volumedrivers.CreateDriver(meta.Driver)
+
+			// cache the volume
+			s.globalLock.Lock()
+			s.options[v.Name()] = meta.Options
+			s.labels[v.Name()] = meta.Labels
+			s.names[v.Name()] = v
+			s.globalLock.Unlock()
+		}(meta)
+	}
+
+	wg.Wait()
+	close(chRemove)
+	s.db.Update(func(tx *bolt.Tx) error {
+		for meta := range chRemove {
+			if err := removeMeta(tx, meta.Name); err != nil {
+				logrus.WithField("volume", meta.Name).Warnf("Error removing stale entry from volume db: %v", err)
+			}
+		}
+		return nil
+	})
+}