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https://issues.apache.org/jira/browse/HADOOP-16112?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16859949#comment-16859949
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Lisheng Sun edited comment on HADOOP-16112 at 6/10/19 11:55 AM:
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[~hexiaoqiao] , thanks for the reply.
Reproduce it as follow:
{code:java}
try {
fs -mkdir /user/test
fs -mkdir /user/test/a
fs -mkdir /user/test/a/b
}
catch (FileAlreadyExistsException e) {
fs -rm -r/user/test/a (another thread)
fs -mkdir /user/test/a/b
}
{code}
The current code is intented to mkdir /user/test/a+timestamp/b, but in actual
mkdir /user/test+timestamp/a/b.
The race condition is reproduced hard by Unit Test.
was (Author: leosun08):
[~hexiaoqiao] , thanks for the reply.
{code:java}
fs -mkdir /user/test
fs -mkdir /user/test/a
fs -mkdir /user/test/a/b fail
catch
fs -rm -r/user/test/a (another thread)
fs -mkdir /user/test/a/b
{code}
The current code is intented to mkdir /user/test/a+timestamp/b, but in actual
mkdir /user/test+timestamp/a/b.
The race condition is reproduced hard by Unit Test.
> Delete the baseTrashPath's subDir leads to don't modify baseTrashPath
> ---------------------------------------------------------------------
>
> Key: HADOOP-16112
> URL: https://issues.apache.org/jira/browse/HADOOP-16112
> Project: Hadoop Common
> Issue Type: Bug
> Components: common
> Affects Versions: 3.2.0
> Reporter: Lisheng Sun
> Priority: Major
> Attachments: HADOOP-16112.001.patch, HADOOP-16112.002.patch
>
>
> There is race condition in TrashPolicyDefault#moveToTrash
> 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(); }
> {color:#ff0000}// case{color}
> {color:#ff0000} other thread deletes existsFilePath here ，the results
> doesn't meet expectation{color}
> {color:#ff0000} for example{color}
> {color:#ff0000} there is
> /user/u_sunlisheng/.Trash/Current/user/u_sunlisheng/b{color}
> {color:#ff0000} 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{color}
> {color:#ff0000} so when existsFilePath is deleted, don't modify
> baseTrashPath. {color}
> 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; }
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