Red Hat Bugzilla – Bug 558181
nfsv4 opening file with O_CREAT|O_EXCL = -EPERM
Last modified: 2011-06-27 10:50:52 EDT
if a filesystem is mounted with nfsv4 (-t nfs4) on a fedora client, and that filesystem is being served on a fedora server, then I cannot logon to KDE. this is because both gdm and the KDE session attempt to create files upon login with O_EXCL on the home directory, and nfsv4 fails that operation (though it DOES create the files, with 0 permission)
exactly the same bug as here:
so nfsv4 is broken on fedora 12, even though there seems to be a patch for the kernel that would solve the problem.
(all fedora 12)
10.254.102.1:/home /home nfs4 _netdev 0 0
/export/home -fsid=1,mp,insecure,ro,no_root_squash vmopslaptop-eth(rw) vmopslaptop-wlan(rw)
The patch that fixed that in RHEL has been upstream for a long time. If you're seeing this problem then it's likely to be unrelated.
In fact, I suspect that the problem is more likely to be something with ID mapping. I'd start by checking that /etc/idmapd.conf are both using the same setting for "Domain =".
Are there any error message being logged to /var/log/messages?
No error messages at all. There is no problem with ID mapping -- idmapd correctly maps existing users on the server to existing users on the laptop that mounts the NFS share. The underlying filesystem is ZFS-FUSE (this should not make a difference, though). The patch MAY be in RHEL, but it is certainly not (or it is ineffective) in the Fedora kernel 184.108.40.206-174 (x86_64).
Oh, one more data point: nfsv3 works well.
Aside from the continuous stream of ESTALEs that I somehow suspect is caused by ZFS-FUSE. But that's a separate rabbit hole and I'm going in there with a shotgun myself later.
I'm stumped then...
It sounds like you're able to do a CREATE operation, but are maybe then failing to open the file and write to it afterward. My suspicion again would be a problem with ID mapping, but maybe it's something else. Maybe capturing some network traffic would help you to determine the cause?
Either way, I don't think it's related to the RHEL bug you referenced, even if the symptoms are similar...
OK open(O_EXCL|O_CREAT) operation fails, but the file itself is indeed created (albeit with zero permissions).
I will attempt to capture network traffic to see this issue from the NFS standpoint. Let's hope my machine doesn't freeze like it did when I ran wireshark last time.
try using tshark.... something like
tshark -o /tmp/data.pcap host <server>
then bzip2 the data.pcap file and post the file as
a data file
This bug appears to have been reported against 'rawhide' during the Fedora 13 development cycle.
Changing version to '13'.
More information and reason for this action is here:
The problem persists on Fedora 13. Ask me for more info if you need.
for the record, not even cp works from /path/somewhere to /nfs/mount/folder/where/i/have/write/permissions
A network trace would help debug this...
Here latest nfs-utils release
Please download test to see if you are still able to see this problem
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