Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422923AbWLUJVz (ORCPT ); Thu, 21 Dec 2006 04:21:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422920AbWLUJVy (ORCPT ); Thu, 21 Dec 2006 04:21:54 -0500 Received: from amsfep16-int.chello.nl ([62.179.120.11]:35959 "EHLO amsfep16-int.chello.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422908AbWLUJVx (ORCPT ); Thu, 21 Dec 2006 04:21:53 -0500 Subject: Re: [PATCH] mm: fix page_mkclean_one (was: 2.6.19 file content corruption on ext3) From: Peter Zijlstra To: schwidefsky@de.ibm.com Cc: Linus Torvalds , Martin Michlmayr , Hugh Dickins , Nick Piggin , Arjan van de Ven , Andrei Popa , Andrew Morton , Linux Kernel Mailing List , Florian Weimer , Marc Haber , Heiko Carstens , Arnd Bergmann , gordonfarquharson@gmail.com In-Reply-To: <1166692586.27750.4.camel@localhost> References: <1166571749.10372.178.camel@twins> <1166605296.10372.191.camel@twins> <1166607554.3365.1354.camel@laptopd505.fenrus.org> <1166614001.10372.205.camel@twins> <1166622979.10372.224.camel@twins> <20061220170323.GA12989@deprecation.cyrius.com> <20061220175309.GT30106@deprecation.cyrius.com> <1166652901.30008.1.camel@twins> <1166655805.30008.18.camel@twins> <1166692586.27750.4.camel@localhost> Content-Type: text/plain Date: Thu, 21 Dec 2006 10:20:12 +0100 Message-Id: <1166692812.32117.2.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1717 Lines: 52 On Thu, 2006-12-21 at 10:16 +0100, Martin Schwidefsky wrote: > On Thu, 2006-12-21 at 00:03 +0100, Peter Zijlstra wrote: > > current version > > Nitpicking .. > > > @@ -444,17 +444,18 @@ static int page_mkclean_one(struct page > > if (!pte) > > goto out; > > > > - if (!pte_dirty(*pte) && !pte_write(*pte)) > > - goto unlock; > > + while (pte_dirty(*pte) || pte_write(*pte)) { > > + pte_t entry; > > > > - entry = ptep_get_and_clear(mm, address, pte); > > - entry = pte_mkclean(entry); > > - entry = pte_wrprotect(entry); > > - ptep_establish(vma, address, pte, entry); > > - lazy_mmu_prot_update(entry); > > - ret = 1; > > + flush_cache_page(vma, address, pte_pfn(*pte)); > > + entry = ptep_clear_flush(vma, address, pte); > > + entry = pte_wrprotect(entry); > > + entry = pte_mkclean(entry); > > + ptep_establish(vma, address, pte, entry); > > Now you are flushing the tlb twice. ptep_clear_flush clears the pte and > flushes the tlb, ptep_establish sets the new pte and flushes the tlb. > Not good. Use set_pte_at instead of the ptep_establish. Yeah, sorry, I already noticed and corrected that :-| Also, I'm dubious about the while thing and stuck a WARN_ON(ret) thing at the beginning of the loop. flush_tlb_page() does IPI the other cpus to flush their tlb too, so there should not be a SMP race, Arjan? > > + lazy_mmu_prot_update(entry); > > + ret = 1; > > + } > > > > -unlock: > > pte_unmap_unlock(pte, ptl); > > out: > > return ret; > - 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/