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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Mon, 15 Mar 2021 14:14:35 +0100
Message-ID: <CAJfpegsb9XrUct5zawN+kS_DSfowBf2BnrZzG+cQXUvsGZZuow@mail.gmail.com>
Subject: Re: [RFC][PATCH 0/3] vfs: Use an xarray instead of inserted bookmarks
 to scan mount list
To:     David Howells <dhowells@redhat.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Matthew Wilcox <willy@infradead.org>,
        Ian Kent <raven@themaw.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
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On Mon, Mar 15, 2021 at 1:07 PM David Howells <dhowells@redhat.com> wrote:
>
>
> Hi Al, Mikl=C3=B3s,
>
> Can we consider replacing the "insert cursor" approach we're currently
> using for proc files to scan the current namespace's mount list[1] with
> something that uses an xarray of mounts indexed by mnt_id?
>
> This has some advantages:
>
>  (1) It's simpler.  We don't need to insert dummy mount objects as
>      bookmarks into the mount list and code that's walking the list doesn=
't
>      have to carefully step over them.
>
>  (2) We can use the file position to represent the mnt_id and can jump to
>      it directly - ie. using seek() to jump to a mount object by its ID.

What happens if the mount at the current position is removed?

Thanks,
Miklos