Bug 220873 - Starting RPC idmapd: Error: RPC MTAB does not exist.
Starting RPC idmapd: Error: RPC MTAB does not exist.
Product: Fedora
Classification: Fedora
Component: util-linux (Show other bugs)
All Linux
medium Severity medium
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Assigned To: Karel Zak
Ben Levenson
Depends On:
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Reported: 2006-12-28 01:36 EST by Need Real Name
Modified: 2008-05-06 13:15 EDT (History)
2 users (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2008-05-06 13:15:17 EDT
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Description Need Real Name 2006-12-28 01:36:01 EST
Description of problem:

If you stop the 'rpcidmapd' service and then do something like 'umount -a', then
it will also umount the rpc_pipefs.

Then when you try to restart 'rpcidmapd' service (or the 'nfs' service which in
turn also starts the 'rpcidmapd' service), you get the error:
    Starting RPC idmapd: Error: RPC MTAB does not exist.

The reason is that the 'rpc_pipefs' filesystem has been unmounted. Now usually
loading the 'sunrpc' module will mount the 'rpc_pipefs'; however, in this case
'sunrpc' is already loaded and therefore not reloaded.

This is a confusing error that is not easy to decipher and solve.
Manually there are two solutions:
1. Unload and reload the 'sunrpc' module (which requires removing the modules
that depend on it and stopping the associated services)
2. Alternatively, mount the filesystem manually
      mount -t rpc_pipefs sunpc /var/lib/nfs/rpc_pipefs

Similarly, if you do 'umount -a'  but don't unload the 'nfsd' module, then the 
'nfsd' filesystem will be unmounted and not remounted when you restart the nfs
service. However, in this case, the init script doesn't even warn you that the
filesystem is not mounted.
Again, manually you have two options
1. Unload and reload the 'nfsd' module
2. Manually create the filesystem
     mount -t nfsd nfsd /proc/fs/nfsd

However, this is all NON-OBVIOUS and could trip people up (it took me many
wasted hours trying to figure out what is happening here :)

I think a better solution would be to test for the existence of the 'rpc_pipefs'
and 'nfsd' at the end of the init.d scrips starting the 'rpcidmapd' and 'nfs'

Then, if the filesystems are either pre-existing or were just created indirectly
by the loading of the 'sunrpc' and 'nfsd' modules then nothing would be
necessary. However, if the filesystems are not there, then the script would just
run the above 'mount' commands to create the filesystems.
Comment 1 Steve Dickson 2007-01-03 19:34:09 EST
This appears to be a bug in the umount code... the fstypes of
rpc_pipefs and nfsd need to be added to the types that are ignored
with the -a arg...
Comment 2 Karel Zak 2007-04-06 07:22:01 EDT
Fixed in util-linux-2.13-0.51.fc7.
Comment 3 Bug Zapper 2008-04-04 01:23:16 EDT
Fedora apologizes that these issues have not been resolved yet. We're
sorry it's taken so long for your bug to be properly triaged and acted
on. We appreciate the time you took to report this issue and want to
make sure no important bugs slip through the cracks.

If you're currently running a version of Fedora Core between 1 and 6,
please note that Fedora no longer maintains these releases. We strongly
encourage you to upgrade to a current Fedora release. In order to
refocus our efforts as a project we are flagging all of the open bugs
for releases which are no longer maintained and closing them.

If this bug is still open against Fedora Core 1 through 6, thirty days
from now, it will be closed 'WONTFIX'. If you can reporduce this bug in
the latest Fedora version, please change to the respective version. If
you are unable to do this, please add a comment to this bug requesting
the change.

Thanks for your help, and we apologize again that we haven't handled
these issues to this point.

The process we are following is outlined here:

We will be following the process here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping to ensure this
doesn't happen again.

And if you'd like to join the bug triage team to help make things
better, check out http://fedoraproject.org/wiki/BugZappers
Comment 4 Bug Zapper 2008-05-06 13:15:15 EDT
This bug is open for a Fedora version that is no longer maintained and
will not be fixed by Fedora. Therefore we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen thus bug against that version.

Thank you for reporting this bug and we are sorry it could not be fixed.

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