From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756915Ab3J2PS1 (ORCPT ); Tue, 29 Oct 2013 11:18:27 -0400 Received: from mga03.intel.com ([143.182.124.21]:55650 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751167Ab3J2PS0 (ORCPT ); Tue, 29 Oct 2013 11:18:26 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,535,1378882800"; d="scan'208";a="314282332" Message-ID: <1383059901.29619.52.camel@sauron.fi.intel.com> Subject: Re: [PATCH 1/1] MTD: UBI: try to avoid program data to NOR flash after erasure interrupted From: Artem Bityutskiy Reply-To: dedekind1@gmail.com To: Qi Wang =?UTF-8?Q?=E7=8E=8B=E8=B5=B7?= "(qiwang)" Cc: "linux-mtd@lists.infradead.org" , Adrian Hunter , "linux-kernel@vger.kernel.org" Date: Tue, 29 Oct 2013 17:18:21 +0200 In-Reply-To: <71CF8D7F32C5C24C9CD1D0E02D52498A770B1B97@NTXXIAMBX02.xacn.micron.com> References: <71CF8D7F32C5C24C9CD1D0E02D52498A77082AC5@NTXXIAMBX02.xacn.micron.com> <71CF8D7F32C5C24C9CD1D0E02D52498A77082DDB@NTXXIAMBX02.xacn.micron.com> <71CF8D7F32C5C24C9CD1D0E02D52498A770AED11@NTXXIAMBX02.xacn.micron.com> <71CF8D7F32C5C24C9CD1D0E02D52498A770AED44@NTXXIAMBX02.xacn.micron.com> <71CF8D7F32C5C24C9CD1D0E02D52498A770AED67@NTXXIAMBX02.xacn.micron.com> <1382779164.5901.1.camel@karhu.quadriga.com> <71CF8D7F32C5C24C9CD1D0E02D52498A770B1B97@NTXXIAMBX02.xacn.micron.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4 (3.6.4-3.fc18) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2013-10-28 at 04:54 +0000, Qi Wang 王起 (qiwang) wrote: > On Sa, 2013-10-26 at 05:19 +0000, Artem Bityutskiy wrote: > >On Thu, 2013-10-10 at 08:28 +0000, Qi Wang 王起 (qiwang) wrote: > >> But I want to say the potential risk is if low level driver program data to > >> this block, it will get “timeout error”. And the timeout period could be very > >> long(almost several minutes), during this period, any operation on NOR flash > >> cannot be accept. so program data to a erasure interrupted block isn’t a > >> sensible action. in order to avoid program a erasure interrupted block, > >> I suggest UBIFS can read this block before program data. the code changing as below: > > > >Yes, reading first sounds like a good idea. Would you please send a > >patch implementing it? > > From: Qi Wang > > nor_erase_prepare() will be called before erase a NOR flash, it will program '0' > into a block to mark this block. But program data into a erasure interrupted block > can cause program timtout(several minutes at most) error, could impact other > operation on NOR flash. So UBIFS can read this block first to avoid unneeded > program operation. > > This patch try to put read operation at at head of write operation in > nor_erase_prepare(), read out the data. > If the data is already corrupt, then no need to program any data into this block, > just go to erase this block. > > Signed-off-by: Qi Wang > --- > diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c > index bf79def..be6ab56 100644 > --- a/drivers/mtd/ubi/io.c > +++ b/drivers/mtd/ubi/io.c > @@ -509,26 +509,10 @@ static int nor_erase_prepare(struct ubi_device *ubi, int pnum) > struct ubi_vid_hdr vid_hdr; > > /* > - * It is important to first invalidate the EC header, and then the VID > - * header. Otherwise a power cut may lead to valid EC header and > - * invalid VID header, in which case UBI will treat this PEB as > - * corrupted and will try to preserve it, and print scary warnings. > - */ > - addr = (loff_t)pnum * ubi->peb_size; > - err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data); > - if (!err) { > - addr += ubi->vid_hdr_aloffset; > - err = mtd_write(ubi->mtd, addr, 4, &written, (void *)&data); > - if (!err) > - return 0; > - } How about structuring the code this way: if (EC header is good) invalidate EC header() if (VID header is good) invalidate VID header() Then you'll handle the case when only one of the headers is already corrupted. -- Best Regards, Artem Bityutskiy