Re: NFS Force Unmounting

[NeilBrown <neilb@suse.com>]

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On Thu, Nov 09 2017, Joshua Watt wrote:

> On Wed, 2017-11-08 at 23:52 +0000, Trond Myklebust wrote:
>> On Thu, 2017-11-09 at 09:34 +1100, NeilBrown wrote:
>> > On Wed, Nov 08 2017, J. Bruce Fields wrote:
>> > 
>> > > 
>> > > I'd be nervous about making "umount -f" do it.  I think
>> > > administrators
>> > > could be unpleasantly surprised in some cases if an "umount -f"
>> > > affects
>> > > other mounts of the same server.
>> > 
>> > I was all set to tell you that it already does, but then tested and
>> > found it doesn't and ....
>
> I tried mounting two different remote paths from an NFS4 server, and
> when I did 'remount,retrans=0', it changed the parameter for both of
> them meaning they are indeed shaing the struct nfs_server (which based
> on my reading of the code is what I would have expected). What
> procedure did you use to test this?

I was using nosharecache, because I was thinking "of course it will
affect all mounts that use sharecache, that is really the same as
a bind-mount".  But I should have been explicit.

With nosharecache, "umount -f" or remount only affects the one mount.
With sharecache (the default) or bind mounts, "umount -f" and remount
affects the underlying superblock which might be mounted at multiple places.

NeilBrown

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