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Date:   Tue, 29 Jun 2021 14:37:41 -0400
From:   "J. Bruce Fields" <bfields@fieldses.org>
To:     Dave Chinner <david@fromorbit.com>
Cc:     linux-fsdevel@vger.kernel.org, dai.ngo@oracle.com,
        linux-nfs@vger.kernel.org
Subject: Re: automatic freeing of space on ENOSPC
Message-ID: <20210629183741.GC1926@fieldses.org>
References: <20210628194908.GB6776@fieldses.org>
 <20210629051149.GP2419729@dread.disaster.area>
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On Tue, Jun 29, 2021 at 03:11:49PM +1000, Dave Chinner wrote:
> On Mon, Jun 28, 2021 at 03:49:08PM -0400, J. Bruce Fields wrote:
> > The NFS server currently revokes a client's state if the client fails to
> > contact it within a lease period (90 seconds by default).  That's
> > harsher than necessary--if a network partition lasts longer than a lease
> > period, but if nobody else needs that client's resources, it'd be nice
> > to be able to hang on to them so that the client could resume normal
> > operation after the network comes back.  So we'd delay revoking the
> > client's state until there's an actual conflict.  But that means we need
> > a way to clean up the client as soon as there is a conflict, to avoid
> > unnecessarily failing operations that conflict with resources held by an
> > expired client.
> 
> I'm not sure what you are asking for filesystems to do here.  This
> seems like an application problem - revoking the client's open file
> state and cleaning up silly rename files is application level
> garbage collection, not filesystem level stuff.

Right, the "application" in this case is knfsd.  It may be keeping some
unlinked files around that it doesn't really need to.  So I'm basically
wondering if I could get a notification from the filesystem that now
would be a good time to close those files.

I think Neil's convinced me this isn't a priority, though....

--b.