From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: booked-page-flag.patch Date: Fri, 16 Feb 2007 00:06:06 -0800 Message-ID: <20070216000606.08372d6f.akpm@linux-foundation.org> References: <20070215004504.023a90f0.akpm@linux-foundation.org> <45D495EA.3060200@redhat.com> <20070215125654.b0f18ab3.akpm@linux-foundation.org> <20070215152352.6ddcfa92.akpm@linux-foundation.org> <20070215234640.d52e5908.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Eric Sandeen , "Theodore Ts'o" , "linux-ext4@vger.kernel.org" To: Alex Tomas Return-path: Received: from smtp.osdl.org ([65.172.181.24]:58926 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966176AbXBPIGp (ORCPT ); Fri, 16 Feb 2007 03:06:45 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri, 16 Feb 2007 10:56:55 +0300 Alex Tomas wrote: > >>>>> Andrew Morton (AM) writes: > > AM> Well, one could just assume that the page has no disk mapping and go and > AM> make the space reservation. Things will work out OK when we come to do > AM> writepage(). > > AM> Or one could do both: call get_block() only if the page was inside i_size. > > well, even so we need to reserve not that block ony, but > also needed metadata (for the worst case). Right. Reserve all the blocks for the page and all the metadata for a page at that file offset. Worst case. > probably this > is work for get_block or some different method? umm, when I did this I think I added a new ->reservepage address_space op and called that from within the VFS's delalloc_prepare_write(). > anyway, > we have to call it if the page is being written partial. Not necessarily. If we're operating in nobh mode that page is brought uptodate in prepare_write().