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Date:   Thu, 20 Apr 2023 22:35:29 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     NeilBrown <neilb@suse.de>
Cc:     Christian Brauner <brauner@kernel.org>,
        Jeff Layton <jlayton@kernel.org>,
        Dave Wysochanski <dwysocha@redhat.com>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-nfs <linux-nfs@vger.kernel.org>,
        David Howells <dhowells@redhat.com>,
        Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH/RFC] VFS: LOOKUP_MOUNTPOINT should used cached info
 whenever possible.
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On Tue, Apr 18, 2023 at 07:26:34AM +1000, NeilBrown wrote:

> MNT_FORCE is, I think, a good idea and a needed functionality that has
> never been implemented well.
> MNT_FORCE causes nfs_umount_begin to be called as you noted, which
> aborts all pending RPCs on that filesystem.

Suppose it happens to be mounted in another namespace as well.  Or bound
at different mountpoint, for that matter.  What should MNT_FORCE do?