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 14:00:08 +0100 Message-ID: <20081007130008.GA3503@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> 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]:57666 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753353AbYJGNAY (ORCPT ); Tue, 7 Oct 2008 09:00:24 -0400 Content-Disposition: inline In-Reply-To: <20081007101207.GA10406@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Christoph Hellwig wrote: > * FIEMAP_EXTENT_ENCODED I like this name better, it seems clearer what it means. > This extent does not consistant of plain filesystem blocks but is > encoded (e.g. encrypted or compressed) or shared with other data by the ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > filesystem. ^^^^^^^^^^ Shared blocks must not be overwritten to the block device when unmounted - but they might be safe to *read*, e.g. by LILO. Shared data is not the only situation where it's unsafe to overwrite blocks in place but they can be read: anything wich data-dependent metadata, such as checksums, data version numbers or indexing. Thus: FIEMAP_EXTENT_READ_ENCODED FIEMAP_EXTENT_WRITE_ENCODED where #define FIEMAP_EXTENT_ENCODED \ (FIEMAP_EXTENT_READ_ENCODED | FIEMAP_EXTENT_WRITE_ENCODED) > Except for continuous nitpicking about this flag which could be > continued in mainline before a release this patch looks good to me. I agree, if there are remaining nits they can be continued in mainline. -- Jamie