From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Polyakov Subject: Re: [WTF] ... is going on with current->fs->{root,mnt} accesses in pohmelfs Date: Wed, 10 Feb 2010 13:12:46 +0300 Message-ID: <20100210101246.GA3509@ioremap.net> References: <20100210100428.GL30031@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Al Viro Return-path: Content-Disposition: inline In-Reply-To: <20100210100428.GL30031@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Feb 10, 2010 at 10:04:28AM +0000, Al Viro (viro@ZenIV.linux.org.uk) wrote: > a) pohmelfs_construct_path_string() will do interesting things if you > call it while chrooted into jail and pohmelfs mounted deeper in that > jail. Try it. Should it walk upto mountpoint? > b) just why do we care about root of chroot jail in pohmelfs_path_length()? > Not to mention anything else, current->fs->root/mnt may be changed under > you if you share current->fs with another thread, but even aside of that, > why does filesystem care about chroot of caller at all? > > What's going on there? It tries to construct a full path upto mountpoint. Effectively it should do similar to non-exported dentry_path() things. There is a race between getting buffer size and filling with the actual path, but we take care about that by restarting if needed. -- Evgeniy Polyakov