container: Use wrapper to ensure commit/abort happens

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

container/view.go

@@ -139,18 +139,28 @@ func (db *memDB) Snapshot() View {
 	}
 }
 
+func (db *memDB) withTxn(cb func(*memdb.Txn) error) error {
+	txn := db.store.Txn(true)
+	err := cb(txn)
+	if err != nil {
+		txn.Abort()
+		return err
+	}
+	txn.Commit()
+	return nil
+}
+
 // Save atomically updates the in-memory store state for a Container.
 // Only read only (deep) copies of containers may be passed in.
 func (db *memDB) Save(c *Container) error {
-	txn := db.store.Txn(true)
-	defer txn.Commit()
+	return db.withTxn(func(txn *memdb.Txn) error {
 		return txn.Insert(memdbContainersTable, c)
+	})
 }
 
 // Delete removes an item by ID
 func (db *memDB) Delete(c *Container) error {
-	txn := db.store.Txn(true)
-
+	return db.withTxn(func(txn *memdb.Txn) error {
 		view := &memdbView{txn: txn}
 		names := view.getNames(c.ID)
 
@@ -159,11 +169,10 @@ func (db *memDB) Delete(c *Container) error {
 		}
 
 		if err := txn.Delete(memdbContainersTable, NewBaseContainer(c.ID, c.Root)); err != nil {
-		txn.Abort()
 			return err
 		}
-	txn.Commit()
 		return nil
+	})
 }
 
 // ReserveName registers a container ID to a name
@@ -171,15 +180,12 @@ func (db *memDB) Delete(c *Container) error {
 // Attempting to reserve a container ID to a name that already exists results in an `ErrNameReserved`
 // A name reservation is globally unique
 func (db *memDB) ReserveName(name, containerID string) error {
-	txn := db.store.Txn(true)
-
+	return db.withTxn(func(txn *memdb.Txn) error {
 		s, err := txn.First(memdbNamesTable, memdbIDIndex, name)
 		if err != nil {
-		txn.Abort()
 			return err
 		}
 		if s != nil {
-		txn.Abort()
 			if s.(nameAssociation).containerID != containerID {
 				return ErrNameReserved
 			}
@@ -187,23 +193,21 @@ func (db *memDB) ReserveName(name, containerID string) error {
 		}
 
 		if err := txn.Insert(memdbNamesTable, nameAssociation{name: name, containerID: containerID}); err != nil {
-		txn.Abort()
 			return err
 		}
-	txn.Commit()
 		return nil
+	})
 }
 
 // ReleaseName releases the reserved name
 // Once released, a name can be reserved again
 func (db *memDB) ReleaseName(name string) error {
-	txn := db.store.Txn(true)
+	return db.withTxn(func(txn *memdb.Txn) error {
 		if err := txn.Delete(memdbNamesTable, nameAssociation{name: name}); err != nil {
-		txn.Abort()
 			return err
 		}
-	txn.Commit()
 		return nil
+	})
 }
 
 type memdbView struct {