From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [RFC PATCH] file as directory Date: Wed, 23 May 2007 12:39:25 +0100 Message-ID: <20070523113925.GT4095@ftp.linux.org.uk> References: <20070523095127.GQ4095@ftp.linux.org.uk> <20070523102437.GS4095@ftp.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org To: Miklos Szeredi Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:57505 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758938AbXEWLj0 (ORCPT ); Wed, 23 May 2007 07:39:26 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org > When the real superblock is created. It could even be the _same_ > super block as the real one. There'd be just the problem of anchoring > the dir-on-file dentries somewhere... > > Or with fuse the dir-on-file mount can just come from any mounted > filesystem, again possibly the same one as the parent. I do actually > test with this. The userspace filesystem supplies a file descriptor, > from which the struct path is extracted and returned from ->enter(). Then I do not understand what this mechanism could be used for, other than an odd way to twist POSIX behaviour and see how much of the userland would survive that. Certainly not useful for your "look into tarball as a tree", unless you seriously want to scan the entire damn fs for tarballs at mount time and set up a superblock for each. And for per-file extended attributes/forks/whatever-you-call-that-abomination it also obviously doesn't help, since you lose them for directories. IOW, what uses do you have in mind? Complete scenario, please...