Add e2e test for quota-based eviction.

Positive test is skipped if quotas not available.

test/e2e_node/util_xfs_linux.go

@@ -0,0 +1,74 @@
+// +build linux
+
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package e2e_node
+
+import (
+	"path/filepath"
+	"syscall"
+
+	"k8s.io/kubernetes/pkg/util/mount"
+)
+
+func detectMountpoint(m mount.Interface, path string) string {
+	path, err := filepath.Abs(path)
+	if err == nil {
+		path, err = filepath.EvalSymlinks(path)
+	}
+	if err != nil {
+		return ""
+	}
+	for path != "" && path != "/" {
+		isNotMount, err := m.IsLikelyNotMountPoint(path)
+		if err != nil {
+			return ""
+		}
+		if !isNotMount {
+			return path
+		}
+		path = filepath.Dir(path)
+	}
+	return "/"
+}
+
+const (
+	xfsMagic = 0x58465342
+)
+
+// XFS over-allocates and then eventually removes that excess allocation.
+// That can lead to a file growing beyond its eventual size, causing
+// an unnecessary eviction:
+//
+// % ls -ls
+// total 32704
+// 32704 -rw-r--r-- 1 rkrawitz rkrawitz 20971520 Jan 15 13:16 foo.bin
+//
+// This issue can be hit regardless of the means used to count storage.
+// It is not present in ext4fs.
+func isXfs(dir string) bool {
+	mountpoint := detectMountpoint(mount.New(""), dir)
+	if mountpoint == "" {
+		return false
+	}
+	var buf syscall.Statfs_t
+	err := syscall.Statfs(mountpoint, &buf)
+	if err != nil {
+		return false
+	}
+	return buf.Type == xfsMagic
+}