/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.hadoop.hbase.master.cleaner;
import java.io.IOException;
import java.util.LinkedList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.io.HFileLink;
import org.apache.hadoop.hbase.util.FSUtils;
import org.apache.hadoop.hbase.util.HFileArchiveUtil;
import org.apache.hadoop.hbase.master.cleaner.BaseHFileCleanerDelegate;
/**
* HFileLink cleaner that determines if a hfile should be deleted.
* HFiles can be deleted only if there're no links to them.
*
* When a HFileLink is created a back reference file is created in:
* /hbase/archive/table/region/cf/.links-hfile/ref-region.ref-table
* To check if the hfile can be deleted the back references folder must be empty.
*/
@InterfaceAudience.Private
public class HFileLinkCleaner extends BaseHFileCleanerDelegate {
private static final Log LOG = LogFactory.getLog(HFileLinkCleaner.class);
private FileSystem fs = null;
@Override
public synchronized boolean isFileDeletable(Path filePath) {
if (this.fs == null) return false;
// HFile Link is always deletable
if (HFileLink.isHFileLink(filePath)) return true;
// If the file is inside a link references directory, means that is a back ref link.
// The back ref can be deleted only if the referenced file doesn't exists.
Path parentDir = filePath.getParent();
if (HFileLink.isBackReferencesDir(parentDir)) {
try {
Path hfilePath = HFileLink.getHFileFromBackReference(getConf(), filePath);
return !fs.exists(hfilePath);
} catch (IOException e) {
LOG.error("Couldn't verify if the referenced file still exists, keep it just in case");
return false;
}
}
// HFile is deletable only if has no links
try {
Path backRefDir = HFileLink.getBackReferencesDir(parentDir, filePath.getName());
return FSUtils.listStatus(fs, backRefDir) == null;
} catch (IOException e) {
LOG.error("Couldn't get the references, not deleting file, just in case");
return false;
}
}
@Override
public void setConf(Configuration conf) {
super.setConf(conf);
// setup filesystem
try {
this.fs = FileSystem.get(this.getConf());
} catch (IOException e) {
LOG.error("Couldn't instantiate the file system, not deleting file, just in case");
}
}
}