linux-kernel - Re: [RFC PATCH] afs: Create a mountpoint through symlink() and remove through rmdir()

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Message-ID: <426585.1582185125@warthog.procyon.org.uk>
Date:   Thu, 20 Feb 2020 07:52:05 +0000
From:   David Howells <dhowells@...hat.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     dhowells@...hat.com, Al Viro <viro@...iv.linux.org.uk>,
        linux-afs@...ts.infradead.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH] afs: Create a mountpoint through symlink() and remove through rmdir()

Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> Your argument that if the prefix is made really long it couldn't be a
> valid symlink at all on AFS is fair, but seems somewhat excessive.

Normally, mountpoint creation and removal would be hidden behind the
appropriate command line tool and not done directly with ln/rmdir.

> The only issue I see with this interface is that you can now create
> these kinds of things by untarring a tar-ball etc.

That would be true with mknod approach too.  Even if tar couldn't do the
second-stage write, it could still create a lot of half-formed mountpoints
by extracting chardevs.

David