From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from web52703.mail.yahoo.com ([206.190.39.154]) by canuck.infradead.org with smtp (Exim 4.42 #1 (Red Hat Linux)) id 1CK1nE-0006e2-JY for linux-mtd@lists.infradead.org; Tue, 19 Oct 2004 17:45:22 -0400 Message-ID: <20041019214518.26339.qmail@web52703.mail.yahoo.com> Date: Tue, 19 Oct 2004 14:45:18 -0700 (PDT) From: Michael Moedt To: tglx@linutronix.de, simon@baydel.com In-Reply-To: <1098186608.12223.857.camel@thomas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-mtd@lists.infradead.org Subject: Re: Bad Blocks On JFFS2/NAND List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --- Thomas Gleixner wrote: > On Tue, 2004-10-19 at 13:22, Simon Haynes wrote: > > I have experienced a problem in which a JFF2 filesystem on NAND > > became full. > > This is a root file system and constant writes to a logfile > > filled the filesystem. On investigation it was found that the > > NAND device now had hundreds of bad blocks. > > > > I started to investigate this and found that JFFS2 was announcing > > > > Newly-erased block contained word 0x1985e002 at offset 0x020f7e00 > > > > Messages which result in my mtd/jffs2 code marking the block bad. > > What I find strange is that a subsequent scan list the new block > > at a different 16k offset when the device erasesize is 16k, in > > this case 0x020f0000. > > Is that because my device is 128Mb and JFFS2 is using this > > 'virtual erase size' of 32k ? > > Yes. The bad block code scans/marks physical blocks and JFFS2 > operates > on virtual ones, if the device size is big enough. > > > I have observed this now on several different NAND devices and it > > seems to be more prominent while performing small writes. > > > > I am currently trying to work out if the erase is not completing, > > or this is the wrong block or something else. > > Hmm, are you using Ready/Busy Pin or the timeout ? > > tglx > Hi guys. This topic has given me a little bit of concern. Could you try to answer a few questions for me? 1. Do you know what usually causes the "Newly-erased block contained word "... error? Is it caused by a interrupted (or otherwise failed) erase? Would power-fail cause this? 2. Would this cause good blocks to be incorrectly [and permanently] marked as bad? I think I may have seen something similar on my system. I'm considering writing a test to see if this is a problem for me, but I'd like to learn more about this also. Thanks, Mike