From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-bw0-f49.google.com ([209.85.214.49]) by casper.infradead.org with esmtp (Exim 4.72 #1 (Red Hat Linux)) id 1POStN-0008G9-CQ for linux-mtd@lists.infradead.org; Fri, 03 Dec 2010 10:29:30 +0000 Received: by bwz5 with SMTP id 5so8492700bwz.36 for ; Fri, 03 Dec 2010 02:28:38 -0800 (PST) Subject: Re: UBIFS partition on NOR flash not mountable after power cut test From: Artem Bityutskiy To: Anatolij Gustschin In-Reply-To: <20101203110719.3a9d14f2@wker> References: <20101129195014.19224240@wker> <20101201130534.5b95ce83@wker> <20101201164447.2215bc58@wker> <1291264926.14534.32.camel@koala> <20101203110719.3a9d14f2@wker> Content-Type: text/plain; charset="UTF-8" Date: Fri, 03 Dec 2010 12:28:05 +0200 Message-ID: <1291372085.2365.49.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org, Detlev Zundel Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2010-12-03 at 11:07 +0100, Anatolij Gustschin wrote: > UBI: scrubbed PEB 149 (LEB 0:19), data moved to PEB 40 > > My question is: should this PEB really be preserved? I think, no. > It was prepared for erasure and would be entirely erased if no > interruption would occur. Well, in general, my thinking is, if only the EC header is corrupted, we do not know why - may be this was just because of some bit-flips or radiation, and UBI better preserves it, just in case. I mean, there is a risk to destroy useful data otherwise. Then the upper layer SW like UBIFS should know what it was erasing, and should re-issue the erasure. This is also a requirement made by the "unstable bits" problem Matthiew found on NAND, and challenged me with. To put is simple: I think it is saver for UBI to preserve it. Upper layers will erase it again if it is not needed. -- Best Regards, Artem Bityutskiy (Артём Битюцкий)