Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751246AbWHKXCi (ORCPT ); Fri, 11 Aug 2006 19:02:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751248AbWHKXCi (ORCPT ); Fri, 11 Aug 2006 19:02:38 -0400 Received: from nf-out-0910.google.com ([64.233.182.191]:7612 "EHLO nf-out-0910.google.com") by vger.kernel.org with ESMTP id S1751246AbWHKXCi (ORCPT ); Fri, 11 Aug 2006 19:02:38 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=DQ8e0NIgUYu49Iy7DoGHNFiDDZerMkgIQk5o9RpK5rstBmC51lmJZDfirQoXpOuH2i+OeRKBYjiIdfeFEEYTHSHOtML7S1QT/dC1VFfMfvdWb1WzNRVK8ASD6F4mwwwdvAgU2n/dmTjhmTA5VPyV357OfdkCRV50U6Uz0Harq2E= Message-ID: <5c49b0ed0608111602g78448347v77b10be2ef1db7f6@mail.gmail.com> Date: Fri, 11 Aug 2006 16:02:35 -0700 From: "Nate Diller" To: "Hans Reiser" Subject: Re: partial reiser4 review comments Cc: "Christoph Hellwig" , "Alexander Zarochentsev" , "Andrew Morton" , reiserfs-dev@namesys.com, linux-kernel@vger.kernel.org In-Reply-To: <44DCC49C.3020304@namesys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20060803001741.4ee9ff72.akpm@osdl.org> <20060803142644.GC20405@infradead.org> <200608061838.35004.zam@namesys.com> <20060809085946.GA6177@infradead.org> <44D9A86F.3010304@namesys.com> <5c49b0ed0608101131h55f1505eo44b78603e2e8d3c2@mail.gmail.com> <44DCC49C.3020304@namesys.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4065 Lines: 104 On 8/11/06, Hans Reiser wrote: > Nate Diller wrote: > > > On 8/9/06, Hans Reiser wrote: > > > >> Christoph Hellwig wrote: > >> > >> > I must admit that standalone code snipplet doesn't really tell me a > >> lot. > >> > > >> >Do you mean the possibility to pass around a filesystem-defined > >> structure > >> >to multiple allocator calls? I'm pretty sure can add that, I though it > >> >would be useful multiple times in the past but always found ways around > >> >it. > >> > > >> > > >> > > >> Assuming I understand your discussion, I see two ways to go, one is to > >> pass around fs specific state and continue to call into the FS many > >> times, and the other is to instead provide the fs with helper functions > >> that accomplish readahead calculation, page allocation, etc., and let > >> the FS keep its state naturally without having to preserve it in some fs > >> defined structure. The second approach would be cleaner code design, > >> that would also ease cross-os porting of filesystems, in my view. > > > > > > the second approach is the one i was heading towards with my > > unfinished a_ops patches. *please* won't someone pay me to do that > > work... > > > > NATE > > > > > You might describe it in a paragraph or so instead of just mentioning > it.....;-) > start by making tree_lock (write) private, using the interface detailed below. No one should be able to add/remove pages from the address space without going through the a_ops interface. this patch is part of a (much) larger unfinished, and outdated, set intended to put this interface in place. people familiar with this code will immediately note that there are a few hard problems to solve here, most notably the various {truncate|invalidate}_mapping_pages calls, and the locking involved. Cleaning up the inode reclaim paths a bit should help this, and that work is unfinished as well. I'm always hesitant to post stuff like this, because -ENOPATCH is really an appropriate response here. NATE diff -urpN linux-2.6.15-rc5-mm1/include/linux/fs.h linux-extent/include/linux/fs.h --- linux-2.6.15-rc5-mm1/include/linux/fs.h 2005-12-10 16:49:30.000000000 -0800 +++ linux-extent/include/linux/fs.h 2006-08-11 15:47:19.000000000 -0700 @@ -340,18 +340,33 @@ struct address_space; struct writeback_control; struct address_space_operations { - int (*writepage)(struct page *page, struct writeback_control *wbc); - int (*readpage)(struct file *, struct page *); - int (*sync_page)(struct page *); - - /* Write back some dirty pages from this mapping. */ - int (*writepages)(struct address_space *, struct writeback_control *); - /* Set a page dirty */ + /* takes lock to move lists, update counts */ int (*set_page_dirty)(struct page *page); + /* get rid of this, all it does is unplug blkdev */ + int (*sync_page)(struct page *); + /* + * Write back dirty pages / invalidate all pages that fall within + * the given page range (end byte inclusive). These only affect + * pages already cached in this mapping. + */ + int (*writepages)(struct address_space *mapping, + struct writeback_control *wbc); + int (*invalidate_range)(struct address_space *mapping, + pgoff_t index, unsigned nr_pages); + + /* + * Read / create pages within the given index extent. These + * silently skip any pages which are already cached in this mapping. + * + * Return the number of pages allocated within the range, or an error. + */ + /* filp here is wierd */ int (*readpages)(struct file *filp, struct address_space *mapping, - struct list_head *pages, unsigned nr_pages); + pgoff_t index, unsigned nr_pages); + int (*instantiate_range)(struct address_space *mapping, pgoff_t index, + unsigned nr_pages); /* * ext3 requires that a successful prepare_write() call be followed - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/