Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757327AbYFYNd0 (ORCPT ); Wed, 25 Jun 2008 09:33:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755790AbYFYNdS (ORCPT ); Wed, 25 Jun 2008 09:33:18 -0400 Received: from fxip-0047f.externet.hu ([88.209.222.127]:36271 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755552AbYFYNdR (ORCPT ); Wed, 25 Jun 2008 09:33:17 -0400 To: johnpol@2ka.mipt.ru CC: miklos@szeredi.hu, jens.axboe@oracle.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, hugh@veritas.com, nickpiggin@yahoo.com.au In-reply-to: <20080625131117.GA28136@2ka.mipt.ru> (message from Evgeniy Polyakov on Wed, 25 Jun 2008 17:11:17 +0400) Subject: Re: [patch 1/2] mm: dont clear PG_uptodate in invalidate_complete_page2() References: <20080625124038.103406301@szeredi.hu> <20080625124121.839734708@szeredi.hu> <20080625131117.GA28136@2ka.mipt.ru> Message-Id: From: Miklos Szeredi Date: Wed, 25 Jun 2008 15:32:55 +0200 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1913 Lines: 50 > > I haven't done an audit of all code that checks the PG_uptodate flags, > > but I suspect, that this change won't have any harmful effects. Most > > code checks page->mapping to see if the page was truncated or > > invalidated, before using it, and retries the find/read on the page if > > it wasn't. The page_cache_pipe_buf_confirm() code is an exception in > > this regard. > > What about writing path, when page is written after some previous write? page->mapping should be checked in the write paths as well. > Like __block_prepare_write()? That's called with the page locked and page->mapping verified. > > Signed-off-by: Miklos Szeredi > > --- > > mm/truncate.c | 1 - > > 1 file changed, 1 deletion(-) > > > > Index: linux-2.6/mm/truncate.c > > =================================================================== > > --- linux-2.6.orig/mm/truncate.c 2008-06-24 20:49:25.000000000 +0200 > > +++ linux-2.6/mm/truncate.c 2008-06-24 23:28:32.000000000 +0200 > > @@ -356,7 +356,6 @@ invalidate_complete_page2(struct address > > BUG_ON(PagePrivate(page)); > > __remove_from_page_cache(page); > > write_unlock_irq(&mapping->tree_lock); > > - ClearPageUptodate(page); > > page_cache_release(page); /* pagecache ref */ > > return 1; > > failed: > > Don't do that, add new function instead which will do exactly that, if > you do need exactly this behaviour. I don't see any point in doing that. > Also why isn't invalidate_complete_page() enough, if you want to have > that page to be half invalidated? I want the page fully invalidated, and I also want splice and nfs exporting to work as for other filesystems. Miklos -- 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/