mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-27 08:40:23 +00:00
50 lines
1.6 KiB
Go
50 lines
1.6 KiB
Go
|
/*
|
||
|
|
* cache.go - Handles cache clearing and management.
|
||
|
|
*
|
||
|
|
* Copyright 2017 Google Inc.
|
||
|
|
* Author: Joe Richey (joerichey@google.com)
|
||
|
|
*
|
||
|
|
* 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 security
|
||
|
|
|
||
|
|
import (
|
||
|
|
"log"
|
||
|
|
"os"
|
||
|
|
|
||
|
|
"golang.org/x/sys/unix"
|
||
|
|
)
|
||
|
|
|
||
|
|
// DropFilesystemCache instructs the kernel to free the reclaimable inodes and
|
||
|
|
// dentries. This has the effect of making encrypted directories whose keys are
|
||
|
|
// not present no longer accessible. Requires root privileges.
|
||
|
|
func DropFilesystemCache() error {
|
||
|
|
// Dirty reclaimable inodes must be synced so that they will be freed.
|
||
|
|
log.Print("syncing changes to filesystem")
|
||
|
|
unix.Sync()
|
||
|
|
|
||
|
|
// See: https://www.kernel.org/doc/Documentation/sysctl/vm.txt
|
||
|
|
log.Print("freeing reclaimable inodes and dentries")
|
||
|
|
file, err := os.OpenFile("/proc/sys/vm/drop_caches", os.O_WRONLY|os.O_SYNC, 0)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
defer file.Close()
|
||
|
|
// "2" just frees the reclaimable inodes and dentries. The associated
|
||
|
|
// pages to these inodes will be freed. We do not need to free the
|
||
|
|
// entire pagecache (as this will severely impact performance).
|
||
|
|
_, err = file.WriteString("2")
|
||
|
|
return err
|
||
|
|
}
|