On Jun 30, 2012, at 9:53 PM, Charles 'Boyo wrote: > Hello. > > I have repeatedly had Linux NFS clients hang while trying to access > files on a NFSv4 mount (Solaris). > Investigations revealed that this client is using a delegation that it > has already returned, resulting in the BAD_STATEID error. > Unfortunately, it then proceeds to hammer the server with these > "doomed" requests, resulting in the client-side unresponsiveness and > constant network traffic. > > A sample trace can be found at http://pastebin.centos.org/39046 > As shown, the READ in frame 10 (line 112) follows the DELEGRETURN in > frame 9 which results in the error. This READ was then repeated > infinitely until either the server or client was restarted. > Disabling delegations on the server-side caused the problem to cease. > So what is wrong with delegations on the client-side? Usually we see this behavior because of a race between an OPEN with delegation and a delegation recall. In this case, however, the client is actively returning a READ delegation, then proceeding to use it anyway. I don't see the server's recall callback, though, and there are other indications that this trace is not complete. So it's hard to be 100% confident. As far as I know, the EL6.2 client does not have support for recovering a single bad STATEID, which is why it is looping. That support is available in mainline kernels 3.0 and later. However, it seems to me that it is a bug for the client to continue using a delegation that it has returned. You have already found one work-around: disable delegations on the NFS server. Or you could mount with NFSv3. Or, if feasible, your application could be modified to use fcntl() locking. > I am using the latest nfs-utils packages and my mount options are as > shown below: > > # cat /etc/redhat-release > CentOS release 6.2 (Final) > > # uname -r > 2.6.32-220.4.1.el6.x86_64 > > # rpm -qa '*nfs*' > nfs-utils-lib-1.1.5-4.el6.x86_64 > nfs-utils-1.2.3-15.el6_2.1.x86_64 > > # grep nfs4 /proc/mounts > 10.51.1.6:/SharedFolder/ /var/LocalMountPoint nfs4 > rw,relatime,vers=4,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=10.51.1.34,minorversion=0,local_lock=none,addr=10.51.1.6 > 0 0 > > Regards, > > Charles > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
