From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754471AbZBRN0d (ORCPT ); Wed, 18 Feb 2009 08:26:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752368AbZBRN0G (ORCPT ); Wed, 18 Feb 2009 08:26:06 -0500 Received: from 36-99-st.zelcom.ru ([80.92.99.36]:60991 "EHLO edward.zelnet.ru" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752052AbZBRN0D (ORCPT ); Wed, 18 Feb 2009 08:26:03 -0500 From: Edward Shishkin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18844.3242.540724.320644@edward.zelnet.ru> Date: Wed, 18 Feb 2009 16:27:06 +0300 To: Andrew Morton Cc: Edward Shishkin , peterz@infradead.org, npiggin@suse.de, rmh3093@gmail.com, randy.dunlap@oracle.com, linux-kernel@vger.kernel.org, reiserfs-devel@vger.kernel.org Subject: [patch 2/2] vfs: (take 2)add set_page_dirty_notag In-Reply-To: <20090217163820.48a2ce68.akpm@linux-foundation.org> References: <18837.24581.181196.569183@edward.zelnet.ru> <1234530519.6519.46.camel@twins> <49957C43.7050701@gmail.com> <1234534150.6519.101.camel@twins> <18838.49922.215481.399653@edward.zelnet.ru> <1234645893.4695.8.camel@laptop> <18841.60432.329341.514726@edward.zelnet.ru> <20090217143506.f6899342.akpm@linux-foundation.org> <499B55A8.50103@gmail.com> <20090217163820.48a2ce68.akpm@linux-foundation.org> X-Mailer: VM 7.17 under 21.5 (beta28) "fuki" (+CVS-20070806) XEmacs Lucid Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In accordance with reiser4 transactional model every dirty page should be "captured" by some atom. However, outside reiser4 context dirty page can not be captured in some cases, as it is accompanied with specific work (jnode creation, etc). Reiser4 recognizes such "anonymous" pages (i.e. pages that were dirtied outside of reiser4) by the tag PAGECACHE_TAG_DIRTY. Pages dirtied inside reiser4 context are not tagged at all: we don't need this. Indeed, once page is dirtied and captured, it is attached to a jnode (a special header to keep a track of transactions). reiser4_set_page_dirty_internal() was the internal reiser4 function that set dirty bit without tagging the page. Having such internal function led to real problems (incorrect task io accounting, etc. because of not updating this internal "friend"). Solution: The following patch adds a core library function that sets a dirty bit without tagging the page. Signed-off-by: Edward Shishkin --- include/linux/mm.h | 1 + mm/page-writeback.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+) --- mmotm.orig/include/linux/mm.h +++ mmotm/include/linux/mm.h @@ -842,6 +842,7 @@ int redirty_page_for_writepage(struct wr void update_page_accounting(struct page *page, struct address_space *mapping); int set_page_dirty(struct page *page); int set_page_dirty_lock(struct page *page); +int set_page_dirty_notag(struct page *page); int clear_page_dirty_for_io(struct page *page); extern unsigned long move_page_tables(struct vm_area_struct *vma, --- mmotm.orig/mm/page-writeback.c +++ mmotm/mm/page-writeback.c @@ -1256,6 +1256,32 @@ int __set_page_dirty_nobuffers(struct pa EXPORT_SYMBOL(__set_page_dirty_nobuffers); /* + * set_page_dirty_notag() -- similar to __set_page_dirty_nobuffers() + * except it doesn't tag the page dirty in the page-cache radix tree. + * This means that the address space using this cannot use the regular + * filemap ->writepages() helpers and must provide its own means of + * tracking and finding non-tagged dirty pages. + * + * NOTE: furthermore, this version also doesn't handle truncate races. + */ +int set_page_dirty_notag(struct page *page) +{ + struct address_space *mapping = page->mapping; + + if (!TestSetPageDirty(page)) { + unsigned long flags; + WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page)); + local_irq_save(flags); + update_page_accounting(page, mapping); + local_irq_restore(flags); + __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); + return 1; + } + return 0; +} +EXPORT_SYMBOL(set_page_dirty_notag); + +/* * When a writepage implementation decides that it doesn't want to write this * page for some reason, it should redirty the locked page via * redirty_page_for_writepage() and it should then unlock the page and return 0