From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 1/4] vfs: vfs-level fiemap interface Date: Tue, 7 Oct 2008 16:31:09 -0400 Message-ID: <20081007203109.GA25653@infradead.org> References: <48EA55AC.2060102@hp.com> <20081006210706.GB8139@mit.edu> <20081007101207.GA10406@infradead.org> <20081007130008.GA3503@shareable.org> <20081007130218.GA4316@infradead.org> <20081007132436.GC3503@shareable.org> <20081007132854.GA15953@infradead.org> <20081007154523.GA15929@mit.edu> <48EB87DE.4090607@hp.com> <20081007185219.GD15929@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20081007185219.GD15929-3s7WtUTddSA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Theodore Tso Cc: jim owens , Christoph Hellwig , Jamie Lokier , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mark Fasheh , Michael Kerrisk , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-api@vger.kernel.org On Tue, Oct 07, 2008 at 02:52:19PM -0400, Theodore Tso wrote: > Right, thanks. This time in proper English. :-) > > * FIEMAP_EXTENT_ENCODED > > This extent does not consist of plain filesystem blocks but is > encoded (e.g. encrypted or compressed). Reading the data in this > extent via I/O to the block device will have undefined results. > > Note that it is *always* undefined to try to update the data > in-place by writing to the indicated location without the > assistance of the filesystem, or to access the data using the > information returned by the FIEMAP interface while the filesystem > is mounted. In other words, user applications may only read the > extent data via I/O to the block device while the filesystem is > unmounted, and then only if the FIEMAP_EXTENT_ENCODED flag is > clear; user applications must not try reading or writing to the > filesystem via the block device under any other circumstances. Looks good! -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html