Is NFSv4 mount interruptible?

[Rick Macklem]

Slawa wrote:
>I have autofs NFSv4 mount with /etc/nfs.map:
>
>/NFS    -nfsv4,intr,soft,sec=krb5i,gssname=host storage01:/
>
>Currently I am see NFS hung and I am can't kill shell and can't
>unmount /NFS.
>
>Is NFSv4 mount interruptible?
>Or intr support only by NFSv3?
Well, in the BUGS section of "man mount_nfs" it notes that soft and intr cannot be
safely used with NFSv4. The problem is that, if an RPC that updates state (Open, Close,...)
terminates, then the state is no longer usable.

You can "umount -f" the file system, but only if no other "umount" is already in progress.
(I am working on a new umount option that will allow "umount -f" to succeed when another
 umount is stuck. It requires "umount(8)" to avoid all the path checking, etc.)

Personally, I would never use "soft" for any mount (except read-only maybe), since it can
result in a write failure when the NFS server is slow. Using "intr" should be ok for NFSv3,
since it is stateless.

rick

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