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From: Matthew Wilcox <willy@infradead.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: David Howells <dhowells@redhat.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Ian Kent <raven@themaw.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 0/3] vfs: Use an xarray instead of inserted bookmarks to scan mount list
Date: Mon, 15 Mar 2021 13:17:23 +0000	[thread overview]
Message-ID: <20210315131723.GW2577561@casper.infradead.org> (raw)
In-Reply-To: <CAJfpegsb9XrUct5zawN+kS_DSfowBf2BnrZzG+cQXUvsGZZuow@mail.gmail.com>

On Mon, Mar 15, 2021 at 02:14:35PM +0100, Miklos Szeredi wrote:
> On Mon, Mar 15, 2021 at 1:07 PM David Howells <dhowells@redhat.com> wrote:
> >
> >
> > Hi Al, Miklós,
> >
> > 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?

xa_find() will move to the next one.

  reply	other threads:[~2021-03-15 13:18 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-15 12:07 [RFC][PATCH 0/3] vfs: Use an xarray instead of inserted bookmarks to scan mount list David Howells
2021-03-15 12:07 ` [PATCH 1/3] vfs: Use an xarray in the mount namespace to handle /proc/mounts list David Howells
2021-03-15 12:07 ` [PATCH 2/3] vfs: Use the mounts_to_id array to do /proc/mounts and co David Howells
2021-03-15 12:54   ` Matthew Wilcox
2021-03-15 12:08 ` [PATCH 3/3] vfs: Remove mount list trawling cursor stuff David Howells
2021-03-15 12:46 ` [RFC][PATCH 0/3] vfs: Use an xarray instead of inserted bookmarks to scan mount list Matthew Wilcox
2021-03-15 13:14 ` Miklos Szeredi
2021-03-15 13:17   ` Matthew Wilcox [this message]
2021-03-15 13:41 ` David Howells
2021-03-15 14:22   ` Miklos Szeredi

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