From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 2/4] sysfs: Implement sysfs manged shadow directory support. Date: Tue, 31 Jul 2007 12:51:57 +0900 Message-ID: <46AEB1DD.5080304@suse.de> References: <1182446577.8138.29.camel@localhost> <20070621211637.GB10583@suse.de> <20070622001328.GA14113@suse.de> <20070625212339.GA13398@kroah.com> <46A3B449.3090409@gmail.com> <20070722202508.GA18018@suse.de> <46A425F9.1030008@gmail.com> <46AD8E92.7080002@suse.de> <46ADDC7F.1090306@sw.ru> <46ADE24E.8020502@suse.de> <46ADEE35.8000109@sw.ru> <46ADF003.3010100@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "Eric W. Biederman" Cc: Linux Containers , Greg KH , Greg KH , Dave Hansen List-Id: containers.vger.kernel.org Hello, Eric W. Biederman wrote: > How close are we to the point where we can get mount sysfs multiple > times and get multiple dentry trees with different super blocks? Yeah, that sounds much better. We only have to pay attention to getting sysfs_dirent tree correct. The rest can be done by just looking up the correct sysfs_dirent in sysfs_lookup(). We would still need to pin all shadows to keep sysfs_get_dentry() working. > That really does sound like the right way to go. Especially as it > simplifies the monitoring of containers. If you want to watch what > the view looks like in some container your bind mount his sysfs and > look at that. > > If we can do that the dcache side at least will be beautiful. And > with a little care we may be able to reduce the work to a special case > in lookup, some extra handling to mark directories as belonging only > to a certain mount of sysfs. > > If we can find something that is stupid and simple I'm all for that. Amen. > To reach the no-kobj utopia we may also need a special device_migrate > that is a super set of device_rename (because sometimes we need to > rename devices when we move them between namespaces). One thing I'm curious about is which semantic is appropriate behavior when a node is migrated from one namespace to another - renaming or deactivation followed by activation in new name space. I guess it doesn't really matter. > So are we close to having a sysfs that we can have multiple super > blocks for? Sorry but I dunno. It sounds much more appealing than other approaches tho. -- tejun