Red Hat Bugzilla – Bug 176303
exportfs -u does not remove individual entries from /var/lib/nfs/xtab or /proc/fs/nfs/exports, and umount fails
Last modified: 2007-11-30 17:07:09 EST
Description of problem:
We have an nfs server exporting 2 filesystems, which should not be interrupted
(hence we cannot simply restart the nfs service).
I have configured further ext3 filesystems to export, for the moment read only,
and exportfs presents these to clients as expected. However, after mounting an
exported filesystem from a client, then unmounting it, exportfs -u does not
completely remove export entries. References are removed from:-
but do not go from:-
Because the kernel entry is still there (is that because of the xtab entries
still there, or causing the xtab entries to still be there?), we are unable to
umount it. Restarting nfs does fix the problem, but doing so interferes with
an important application.
Version-Release number of selected component (if applicable):
nfs-utils-1.0.6-42EL with kernel-smp-2.4.21-37.EL
Steps to Reproduce:
1. (server): exportfs -o mp,ro,no_root_squash \*:/stage/test
2. (client): mount server:/stage/test /mnt/test ; umount /mnt/test
3. (server): exportfs -u \*:/stage/test
4. umount /stage/test
# fuser -v /stage/test
USER PID ACCESS COMMAND
root kernel mount /stage/test
# umount /stage/test
umount: /stage/test: device is busy
This remains the case until nfs is restarted on the server.
Filesystem should have umounted properly. I would also expect xtab references
for the unexported share to disappear.
If the filesystem is simply exported and then unexported, without being mounted
at all then there is no problem. But once the entries appear
in /var/lib/nfs/xtab and /proc/fs/nfs/exports then those entries will not go
until nfs is restarted on the server.
Hi, if you downgrade to 1.0.6-38 or older, does the problem go away? I.e., can
you unmount the file system?
Sorry - clarification - if you downgrade nfs-utils to version 1.0.6-38 or older
(for example, 1.0.6-33 is known to make this problem go away), can you unmount
the file system?
The patch for this problem is in Bug# 172100
*** This bug has been marked as a duplicate of 172100 ***
The answer to this is I don't know, I don't have the older package, and this
is a production system I can't play with anyway. However, I suspect that is
the case. The problem was resolved in bug 172100 with the nfs-utils-1.0.6-
Go the 1 line patch!