Quoting Jim Davis (jdavis@cs.arizona.edu):
Mail from a user on a linux Redhat 5.1 system mounting files from a F520 running 5.1.2R3, and getting some odd results with the .snapshot files. Sounds client-side to me, but I'm not real familiar with linux:
As Bruce said, it's impossible to tell without a full transcript. However, I have seen some code in the Linux kernel that seems to address the ill-defined issue of "snapshot confusion". Apparently this is a problem in Linux because they hash inodes (at least sometimes) by fileid, and the fileid for a directory and it's snapshot are the same. The most common manifestation of this problem, according to several people on the linux newsgroups, is a directory that suddenly becomes read-only because the attributes for the snapshot and the real directory got confused.
(For what it's worth, we have a number of Linux boxes mounting many Netapp filers here internally, and I've never seen either of these problems nor heard of anyone else seeing them.)
In any case, the Linux user may find the following information useful if he's seeing this often. A kernel-compile-time option, CONFIG_NFS_SNAPSHOT, was added to Linux around 2.1.130, and is in the 2.2.0-pre releases. This option can be flipped on with the kernel configurator and then compiled in. It sounds like it might help, but again, we have no data on this issue. If your user has success with this or wants to provide additional detail, I'd love to see it.
Thanks Paul Eastham NetApp Engineering