From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [PATCH 1/4] vfs: vfs-level fiemap interface Date: Tue, 7 Oct 2008 14:24:36 +0100 Message-ID: <20081007132436.GC3503@shareable.org> References: <1223071147-27180-1-git-send-email-tytso@mit.edu> <1223071147-27180-2-git-send-email-tytso@mit.edu> <20081004021251.GA29174@mit.edu> <48EA55AC.2060102@hp.com> <20081006210706.GB8139@mit.edu> <20081007101207.GA10406@infradead.org> <20081007130008.GA3503@shareable.org> <20081007130218.GA4316@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Tso , jim owens , linux-fsdevel@vger.kernel.org, Mark Fasheh , Michael Kerrisk , linux-abi@vger.kernel.org To: Christoph Hellwig Return-path: Received: from mail2.shareable.org ([80.68.89.115]:35915 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753350AbYJGNYn (ORCPT ); Tue, 7 Oct 2008 09:24:43 -0400 Content-Disposition: inline In-Reply-To: <20081007130218.GA4316@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Christoph Hellwig wrote: > > Shared blocks must not be overwritten to the block device when > > unmounted - but they might be safe to *read*, e.g. by LILO. > > I guess my terminalogy wasn't clear enough. I didn't mean shared by > multiple files, but different areas in one block used by different > files, e.g. reiserfs tail merging or ufs fragments. These things always > were a pain in the neck for lilo. Fair enough. Ok, without getting in the way any more :-) it would be good to clarify in the description whether !(flags & FIEMAP_EXTENT_ENCODED) means only reading is allowed, or if it means writing over the data blocks is safe too. Just so that filesystems will know whether to set the flag for blocks which can be read but not written. This may include tail-merged blocks. -- Jamie