Red Hat Bugzilla – Bug 116873
Timeouts Not Inherited by Submounts of Automount Daemon
Last modified: 2007-11-30 17:07:00 EST
Description of problem: It appears that submounts (automount --submount /path/subpath map_type ...) do not inherit the timeout parameter of their parent mounts (automount --timeout seconds /path map_type ...), so they expire according to the default timeout of 5 minutes rather than the user-specified number of seconds. Version-Release number of selected component (if applicable): autofs-3.1.7-41 How reproducible: Always. Steps to Reproduce: 1. In /etc/auto.master: /misc /etc/auto.misc --timeout=60 2. In /etc/auto.misc: sub -fstype=autofs /etc/auto.sub 3. In /etc/auto.sub: * some_valid_server:/some_valid_exported_path 4. Make sure that some_valid_server:/some_valid_exported_path is properly exported via /etc/exports on the appropriate server, and make sure that it can be manually mounted on the client where /etc/auto.sub has been installed 5. Restart autofs and cause /misc/sub/some_valid_exported_path to get mounted using the following command: ls /misc/sub/some_valid_exported_path 6. Wait at least 1 minute, but no more than 4 minutes, and check to see if /misc/sub/some_valid_exported_path is still mounted using the following command: df | grep /misc/sub/some_valid_exported_path Actual results: After 1 minute, the user-specified timeout in /etc/auto.master, the mounted path /misc/sub/some_valid_exported_path is still mounted. After 5 minutes, the autofs default timeout value, it gets unmounted. Looking at the process table reveals that the parent automount daemon has the "--timeout 60" flag, but its child only has a "--submount" flag with no explicit timeout. As a result, the parent remains mounted until the child gets unmounted after the default timeout period has elapsed. Expected results: All children of the parent automount daemon should inherit the "-- timeout 60" flag from their parents. If this means re-examining the /etc/auto.master file, so be it, but there must be a more elegant way to communicate this timeout from the parent daemon to its children, and from its children to all of their grandchildren. Additional info: Nada.
Step #6 of "Steps to Reproduce" was wrong. Correction: Do not use df as this will access the remote filesystem and prevent the automounter from unmounting. Instead, check /etc/mtab directly to see if the path is still mounted as follows: grep /misc/sub/some_valid_exported_path /etc/mtab Also, it seems to me that it would be very simple for the automount daemon to inclue the appropriate "--timeout" flag when it spawns each of its children with the "--submount" flag. This would be a quick, easy, and presumably safe fix.
I'll look into this.
Autofs4 takes care of this, and we'll be moving to this in the next update.
An errata has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2004-284.html