From: Ray Van Dolson <rvandolson@esri.com>
To: linux-nfs@vger.kernel.org
Subject: NFS server responds to SYN with ACK only
Date: Wed, 20 Jul 2011 12:23:42 -0700 [thread overview]
Message-ID: <20110720192341.GA18167@esri.com> (raw)
We have a couple legacy CentOS (RHEL)-based appliances with slightly
dated NFS implementations.
Server (CentOS 4 based):
nfs-utils-1.0.6-70.EL4
Kernel 2.6.9-42.0.10.plus.c4smp
Client (CentOS 5 based):
nfs-utils-1.0.9-42.el5.x86_64
Kernel 2.6.18-164.15.1.el5
The client has a long-lived NFSv3 mount to the server that sometimes
stops responding (blocks). We can lazy unmount it, but subsequent
mount requests hang and the following is observed via tcpdump:
1. Client GETPORT for NFS service succeeds.
2. Client GETPORT for MOUNT succeeds
3. Client MNT call succeeds (server gives valid response including
file handle)
4. Client sends a SYN packet to NFS port on server
5. Server responds with ACK *only*
When we bounce the NFS daemon on the server, everything starts working
and in step 5 above, we get a SYN,ACK as expected in response to #4,
and everything proceeds along nicely.
Does this jog anybody on a long-ago fixed bug? I'm thinking updating
the kernel and nfs-utils on the server will likely help, but would love
to find where behavior like the above is referenced as a "bug".
Thanks,
Ray
next reply other threads:[~2011-07-20 19:43 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-20 19:23 Ray Van Dolson [this message]
2011-07-21 16:51 ` NFS server responds to SYN with ACK only Ray Van Dolson
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