[Bug 1243367] Re: tar complains about changed directory which hasn't changed

[Don Hirst]

It is now going on 5 years and this bug is still alive and well.  I'm
trying to migrate off of 14.04.5, and need to use tar for creating
backups of folders and files to analyze for migration purposes.  This
bug is getting in the way of my work.  I copied the live folder / files
to an intermediate folder / files, and tried to use tar on that, no
luck; it errors out almost immediately.

I am running as root and trying to create an archive of /etc.  
The error says:  tar: ./.: file changed as we read it

My instance is running as a VM in VBox

SCP:  Ubuntu 14.04.5, up-to-date
TAR:  tar --version says:  tar (GNU tar) 1.27.1

Suggestions welcomed.

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https://bugs.launchpad.net/bugs/1243367

Title:
  tar complains about changed directory which hasn't changed

Status in tar package in Ubuntu:
  Confirmed

Bug description:
  I'm using Ubuntu 14.04 dev with tar 1.26+dfsg-8 and sometimes I'm
  seeing the message "tar: .: file changed as we read it" which seems to
  not be true. This bugs seems to be very difficult to reproduce and
  even the reproducing behavior is really annoying. As I got today on
  testing the chance for easy reproducing I have made a look with
  inotifywait what is happening:

  sworddragon at ubuntu:~$ mkdir tmp
  sworddragon at ubuntu:~$ inotifywait -mr tmp &
  [1] 12445
  sworddragon at ubuntu:~$ Setting up watches.  Beware: since -r was given, this may take a while!
  Watches established.
  ^C
  sworddragon at ubuntu:~$ cd tmp
  sworddragon at ubuntu:~/tmp$ tar --exclude "*\.tar" -zcf test.tar .
  tmp/ OPEN,ISDIR 
  tmp/ CREATE test.tar
  tmp/ OPEN test.tar
  tar: .: file changed as we read it
  tmp/ CLOSE_NOWRITE,CLOSE,ISDIR 
  tmp/ MODIFY test.tar
  tmp/ CLOSE_WRITE,CLOSE test.tar
  sworddragon at ubuntu:~/tmp$ rm test.tar
  tmp/ DELETE test.tar
  sworddragon at ubuntu:~/tmp$ tar --exclude "*\.tar" -cf test.tar .
  tmp/ CREATE test.tar
  tmp/ OPEN test.tar
  tmp/ OPEN,ISDIR 
  tmp/ CLOSE_NOWRITE,CLOSE,ISDIR 
  tmp/ MODIFY test.tar
  tmp/ CLOSE_WRITE,CLOSE test.tar
  sworddragon at ubuntu:~/tmp$ rm test.tar
  tmp/ DELETE test.tar
  sworddragon at ubuntu:~/tmp$ tar --exclude "*\.tar" -zcf test.tar .
  tmp/ OPEN,ISDIR 
  tmp/ CREATE test.tar
  tmp/ OPEN test.tar
  tar: .: file changed as we read it
  tmp/ CLOSE_NOWRITE,CLOSE,ISDIR 
  tmp/ MODIFY test.tar
  tmp/ CLOSE_WRITE,CLOSE test.tar
  sworddragon at ubuntu:~/tmp$ tar --exclude "*\.tar" -zcf test.tar .
  tmp/ OPEN,ISDIR 
  tmp/ MODIFY test.tar
  tmp/ OPEN test.tar
  tmp/ CLOSE_NOWRITE,CLOSE,ISDIR 
  tmp/ MODIFY test.tar
  tmp/ CLOSE_WRITE,CLOSE test.tar

  
  The bug only appears if a compression is activated (even with -J) and the tar archive doesn't already exist (tested both multiple times). The curious is if I'm closing the terminal and open it again I'm not able to reproduce this anymore. The bug will then randomly appear whenever I'm using tar.

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