[HADOOP-15893] fs.TrashPolicyDefault: can't create trash directory and race condition

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Component/s: common
• Assignee: sunlisheng
• Reporter: sunlisheng
• Created: 31/Oct/18 09:53
• Updated: 12/Jun/23 21:45

Description

there is race condition in method moveToTrash class TrashPolicyDefault

try {
if (!fs.mkdirs(baseTrashPath, PERMISSION))

{ // create current LOG.warn("Can't create(mkdir) trash directory: " + baseTrashPath); return false; }

} catch (FileAlreadyExistsException e) {
// find the path which is not a directory, and modify baseTrashPath
// & trashPath, then mkdirs
Path existsFilePath = baseTrashPath;
while (!fs.exists(existsFilePath))

{ existsFilePath = existsFilePath.getParent(); }

// case

  other thread deletes existsFilePath here ，the results doesn't  meet expectation

 for example

   there is /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng/b

   when delete /user/u_sunlisheng/b/a. if existsFilePath is deleted, the result is /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng+timstamp/b/a

  so  when existsFilePath is deleted, don't modify baseTrashPath.    

baseTrashPath = new Path(baseTrashPath.toString().replace(
existsFilePath.toString(), existsFilePath.toString() + Time.now())
);

trashPath = new Path(baseTrashPath, trashPath.getName());
// retry, ignore current failure
--i;
continue;
} catch (IOException e)

{ LOG.warn("Can't create trash directory: " + baseTrashPath, e); cause = e; break; }

 

Issue Links

• Blocked: HADOOP-15633 fs.TrashPolicyDefault: Can't create trash directory