[HBASE-20668] Avoid permission change if ExportSnapshot's copy fails

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.1.0
• Hadoop Flags: Reviewed
• Assignee: Ted Yu
• Reporter: Ted Yu
• Created: 01/Jun/18 09:36
• Updated: 21/Sep/18 20:53
• Resolved: 01/Jun/18 21:39

Description

The exception from FileSystem operation in the finally block of ExportSnapshot#doWork may hide the real exception from FileUtil.copy call.

I was debugging the following error romil.choksi saw during testing ExportSnapshot :

2018-06-01 02:40:52,363|INFO|MainThread|machine.py:167 - run()||GUID=1cacb7bc-f7cc-4710-82e0-4a4513f0c1f9|2018-06-01 02:40:52,358 ERROR [main] util.AbstractHBaseTool: Error      running command-line tool
2018-06-01 02:40:52,363|INFO|MainThread|machine.py:167 - run()||GUID=1cacb7bc-f7cc-4710-82e0-4a4513f0c1f9|java.io.FileNotFoundException: Directory/File does not exist /apps/     hbase/data/.hbase-snapshot/.tmp/snapshot_table_334546
2018-06-01 02:40:52,364|INFO|MainThread|machine.py:167 - run()||GUID=1cacb7bc-f7cc-4710-82e0-4a4513f0c1f9|at org.apache.hadoop.hdfs.server.namenode.FSDirectory.                  checkOwner(FSDirectory.java:1777)
2018-06-01 02:40:52,364|INFO|MainThread|machine.py:167 - run()||GUID=1cacb7bc-f7cc-4710-82e0-4a4513f0c1f9|at org.apache.hadoop.hdfs.server.namenode.FSDirAttrOp.                  setOwner(FSDirAttrOp.java:82)

Here is corresponding code (with extra log added):

    try {
      LOG.info("Copy Snapshot Manifest from " + snapshotDir + " to " + initialOutputSnapshotDir);
      boolean ret = FileUtil.copy(inputFs, snapshotDir, outputFs, initialOutputSnapshotDir, false,
          false, conf);
      LOG.info("return val = " + ret);
    } catch (IOException e) {
      LOG.warn("Failed to copy the snapshot directory: from=" +
          snapshotDir + " to=" + initialOutputSnapshotDir, e);
      throw new ExportSnapshotException("Failed to copy the snapshot directory: from=" +
        snapshotDir + " to=" + initialOutputSnapshotDir, e);
    } finally {
      if (filesUser != null || filesGroup != null) {
        LOG.warn((filesUser == null ? "" : "Change the owner of " + needSetOwnerDir + " to "
            + filesUser)
            + (filesGroup == null ? "" : ", Change the group of " + needSetOwnerDir + " to "
            + filesGroup));
        setOwner(outputFs, needSetOwnerDir, filesUser, filesGroup, true);
      }

"return val = " was not seen in rerun of the test.
This is what the additional log revealed:

2018-06-01 09:22:54,247|INFO|MainThread|machine.py:167 - run()||GUID=3961d249-9981-429d-81a8-39c7df53cf58|2018-06-01 09:22:54,241 WARN  [main] snapshot.ExportSnapshot: Failed to copy the snapshot directory: from=hdfs://ns1/apps/hbase/data/.hbase-snapshot/snapshot_table_157842 to=hdfs://ns3/apps/hbase/data/.hbase-snapshot/.tmp/snapshot_table_157842
2018-06-01 09:22:54,248|INFO|MainThread|machine.py:167 - run()||GUID=3961d249-9981-429d-81a8-39c7df53cf58|org.apache.hadoop.security.AccessControlException: Permission denied:   user=hbase, access=WRITE, inode="/apps/hbase/data/.hbase-snapshot/.tmp":hrt_qa:hadoop:dr----x-wT
2018-06-01 09:22:54,248|INFO|MainThread|machine.py:167 - run()||GUID=3961d249-9981-429d-81a8-39c7df53cf58|at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.          check(FSPermissionChecker.java:399)
2018-06-01 09:22:54,249|INFO|MainThread|machine.py:167 - run()||GUID=3961d249-9981-429d-81a8-39c7df53cf58|at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.          checkPermission(FSPermissionChecker.java:255)

It turned out that the exception from setOwner call in the finally block eclipsed the real exception.