From: David Howells <dhowells@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: dhowells@redhat.com, Michal Suchanek <hramrach@centrum.cz>,
Ian Kent <ikent@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Ric Wheeler <rwheeler@redhat.com>,
Alexander Viro <aviro@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Jeff Moyer <jmoyer@redhat.com>
Subject: Re: Union mount and lockdep design issues
Date: Wed, 13 Jul 2011 13:02:05 +0100 [thread overview]
Message-ID: <30216.1310558525@redhat.com> (raw)
In-Reply-To: <87tyar6gv8.fsf@tucsk.pomaz.szeredi.hu>
Miklos Szeredi <miklos@szeredi.hu> wrote:
> Overlayfs never locks both upper and lower at the same time, which means
> there's no AB-BA locking dependency. The lock orderings are:
What you're talking about is not analogous to the situation I'm seeing with
unionmount.
You actually have three filesystems in overlayfs. The interaction between
overlayfs-and-upperfs and overlayfs-and-lowerfs is the equivalent in
unionmount terms to upperfs-and-lowerfs. This is where the lockdep issue
lies.
David
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: dhowells@redhat.com, Michal Suchanek <hramrach@centrum.cz>,
Ian Kent <ikent@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Ric Wheeler <rwheeler@redhat.com>,
Alexander Viro <aviro@redhat.com>,
Christoph Hellwig <hch@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Jeff Moyer <jmoyer@redhat.com>
Subject: Re: Union mount and lockdep design issues
Date: Wed, 13 Jul 2011 13:02:05 +0100 [thread overview]
Message-ID: <30216.1310558525@redhat.com> (raw)
In-Reply-To: <87tyar6gv8.fsf@tucsk.pomaz.szeredi.hu>
Miklos Szeredi <miklos@szeredi.hu> wrote:
> Overlayfs never locks both upper and lower at the same time, which means
> there's no AB-BA locking dependency. The lock orderings are:
What you're talking about is not analogous to the situation I'm seeing with
unionmount.
You actually have three filesystems in overlayfs. The interaction between
overlayfs-and-upperfs and overlayfs-and-lowerfs is the equivalent in
unionmount terms to upperfs-and-lowerfs. This is where the lockdep issue
lies.
David
next prev parent reply other threads:[~2011-07-13 12:02 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 15:00 Unionmount status? Michal Suchanek
2011-04-12 20:31 ` Ric Wheeler
2011-04-12 21:36 ` Michal Suchanek
2011-04-13 14:18 ` Jiri Kosina
2011-04-13 15:13 ` Michal Suchanek
2011-04-14 8:38 ` Miklos Szeredi
2011-04-14 9:48 ` Sedat Dilek
2011-04-14 9:58 ` Miklos Szeredi
2011-04-15 11:22 ` Michal Suchanek
2011-04-15 11:31 ` Miklos Szeredi
2011-04-15 11:51 ` Michal Suchanek
2011-04-15 12:29 ` Miklos Szeredi
2011-04-15 12:34 ` Michal Suchanek
2011-04-15 12:34 ` Michal Suchanek
2011-04-15 12:48 ` Miklos Szeredi
2011-04-15 21:48 ` Hugh Dickins
2011-04-15 22:18 ` Andreas Dilger
2011-04-18 13:31 ` Michal Suchanek
2011-04-18 13:31 ` Michal Suchanek
2011-04-19 20:04 ` [PATCH] tmpfs: implement generic xattr support Miklos Szeredi
2011-04-20 2:18 ` Phillip Lougher
2011-04-20 2:18 ` Phillip Lougher
2011-04-20 13:43 ` Miklos Szeredi
2011-04-21 6:59 ` Michal Suchanek
2011-04-21 9:08 ` Miklos Szeredi
2011-04-21 10:59 ` Michal Suchanek
2011-04-21 14:58 ` Jordi Pujol
2011-04-21 15:22 ` Michal Suchanek
2011-04-21 15:43 ` Michal Suchanek
2011-04-21 17:26 ` Miklos Szeredi
2011-04-21 19:17 ` Michal Suchanek
2011-04-20 16:00 ` Serge E. Hallyn
2011-05-12 4:20 ` Hugh Dickins
2011-05-12 7:52 ` Michal Suchanek
2011-05-12 12:27 ` Miklos Szeredi
2011-05-12 14:00 ` Miklos Szeredi
2011-05-12 16:52 ` Hugh Dickins
2011-04-18 13:34 ` Unionmount status? Michal Suchanek
2011-04-18 13:34 ` Michal Suchanek
2011-04-18 13:37 ` Michal Suchanek
2011-04-18 13:37 ` Michal Suchanek
2011-04-13 17:26 ` Ric Wheeler
2011-04-13 18:58 ` Michal Suchanek
2011-04-13 19:11 ` Ric Wheeler
2011-04-13 19:47 ` Michal Suchanek
2011-04-14 4:50 ` Ian Kent
2011-04-14 9:32 ` Michal Suchanek
2011-04-14 9:40 ` Miklos Szeredi
2011-04-14 13:21 ` Ric Wheeler
2011-04-14 14:54 ` Michal Suchanek
2011-04-15 16:31 ` Ric Wheeler
2011-04-14 19:14 ` David Howells
2011-06-29 9:39 ` Union mount and overlayfs bake off? Ric Wheeler
2011-06-29 10:17 ` David Howells
2011-06-30 12:44 ` Miklos Szeredi
2011-07-10 8:28 ` Union mount and lockdep design issues Ric Wheeler
2011-07-10 13:48 ` Peter Zijlstra
2011-07-11 8:35 ` Michal Suchanek
2011-07-11 11:01 ` David Howells
2011-07-11 12:00 ` Peter Zijlstra
2011-07-11 13:36 ` Michal Suchanek
2011-07-11 13:36 ` Michal Suchanek
2011-07-11 13:50 ` Ian Kent
2011-07-11 16:17 ` Michal Suchanek
2011-07-11 17:23 ` Ian Kent
2011-07-11 18:08 ` Michal Suchanek
2011-07-12 8:30 ` Miklos Szeredi
2011-07-12 9:58 ` Michal Suchanek
2011-07-12 11:45 ` Miklos Szeredi
2011-07-12 18:49 ` Michal Suchanek
2011-07-13 9:49 ` Miklos Szeredi
2011-07-13 12:02 ` David Howells [this message]
2011-07-13 12:02 ` David Howells
2011-07-13 13:20 ` Miklos Szeredi
2011-07-14 0:57 ` David Howells
2011-07-14 0:57 ` David Howells
2011-07-11 13:54 ` David Howells
2011-07-11 14:02 ` Peter Zijlstra
2011-07-11 14:50 ` [PATCH 1/2] VFS: Pass mount flags to sget() David Howells
2011-07-11 14:50 ` [PATCH 2/2] union-mount: Duplicate the i_{, dir_}mutex lock classes and use for upper layer David Howells
2011-06-29 11:40 ` Union mount and overlayfs bake off? Michal Suchanek
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