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  1. Jenkins
  2. JENKINS-20610

FileAlreadyExistsException upon "deleted" symlink while (re)creating it

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    Details

    • Type: Bug
    • Status: Closed (View Workflow)
    • Priority: Major
    • Resolution: Fixed
    • Component/s: core
    • Labels:
      None
    • Similar Issues:

      Description

      Some Jenkins instances of ours do log FileAlreadyExistsException-s from time to time:

      java.nio.file.FileAlreadyExistsException: (path2onesJob)/lastSuccessful
      at sun.nio.fs.UnixException.translateToIOException(UnixException.java:88)
      (..) at hudson.Util.createSymlinkJava7(Util.java:1122)
      (..)

      -Above trace mapping to 1.509.2.
      Code shows "proper" deletion of symlink prior to (re)creating it:
      (..)
      filesC.getMethod("deleteIfExists", pathC).invoke(null, path);
      Object noAttrs = Array.newInstance(Class.forName("java.nio.file.attribute.FileAttribute"), 0);
      filesC.getMethod("createSymbolicLink", pathC, pathC, noAttrs.getClass()).invoke(null, path, target, noAttrs);

      -Looking at that code and around,
      I suspect some occasional race condition by lack of concurrency safeness:
      1. thread-A deletes any existing lastSuccessful symlink (so far so good)
      2. thread-B deletes it too but that is a no-op by now, given 1.
      3. thread-A (re)creates the symlink (no problem yet)
      4. thread-B recreates the symlink, but that throws our hereby exception, given 3. (problematic).

      -Unless such initial deletion fails because of this:
      "On some operating systems it may not be possible to remove a file when it is open and in use by this Java virtual machine or other programs."
      http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#deleteIfExists(java.nio.file.Path)

      -Assuming the above threading hypothesis and solving it to be hard & risky.

        Attachments

          Activity

          marcomiller Marco Miller created issue -
          marcomiller Marco Miller made changes -
          Field Original Value New Value
          Status Open [ 1 ] In Progress [ 3 ]
          scm_issue_link SCM/JIRA link daemon made changes -
          Resolution Fixed [ 1 ]
          Status In Progress [ 3 ] Resolved [ 5 ]
          marcomiller Marco Miller made changes -
          Status Resolved [ 5 ] Closed [ 6 ]
          rtyler R. Tyler Croy made changes -
          Workflow JNJira [ 152135 ] JNJira + In-Review [ 207160 ]

            People

            Assignee:
            marcomiller Marco Miller
            Reporter:
            marcomiller Marco Miller
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              Dates

              Created:
              Updated:
              Resolved: