From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.122.233] helo=mgw-mx06.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1Nzn2U-0006Dq-A8 for linux-mtd@lists.infradead.org; Thu, 08 Apr 2010 08:24:39 +0000 Subject: Re: UBIFS and MLC NAND Flash From: Artem Bityutskiy To: "Pedro I. Sanchez" In-Reply-To: <4BA7A183.7040206@fosstel.com> References: <4BA7A183.7040206@fosstel.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 08 Apr 2010 11:22:41 +0300 Message-ID: <1270714961.6754.107.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: linux-mtd@lists.infradead.org Reply-To: dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, On Mon, 2010-03-22 at 12:57 -0400, Pedro I. Sanchez wrote: > Hello, > > I have a few questions regarding this topic. > > 1. The UBIFS FAQ has a summary of the state of the support for MLC NAND > flash here: > > http://www.linux-mtd.infradead.org/faq/ubifs.html#L_ubifs_mlc > > The question is, is this still the case? Does the FAQ reflect the > current state of affairs? I think so. > 2. I have several boards with MLC NAND flash running the Linux kernel > 2.6.29 and UBIFS. I am seeing a fairly large rate of file "corruption" > errors, files that all of a sudden become unreadable. Curiously enough, > they have been read-only files in all cases, program executables and > shared libraries. Hmm. Do you do unclean power cuts? > Would upgrading to a more recent kernel, or back porting the latest > UBIFS code, help? Shall I expect better support for MLC NAND flash in > the latest UBIFS code? You did not specify whether you pulled the ubifs-v2.6.29.git tree. If you did this, then your UBI/UBIFS should be the same as in the latest kernels. Please, do this, although this will probably not solve your corruption problems, but you'll have other bug-fixes we have made since 2.6.29 times. Please, take a look here as well: http://www.linux-mtd.infradead.org/doc/ubifs.html#L_how_send_bugreport Did you run MTD tests? If no, run them. You may have issues on driver/HW levels. Vs. "Shall I expect better support" - not as far as I know, because I have not heard if anyone is working on this. But you could do that and contribute. > 3. I am also seeing other errors where it is the U-Boot or the Kernel > partitions that become corrupted. UBIFS is not involved there directly > since these partitions are at the mtd level and outside the UBI layer. > > More specifically, my flash is partitioned as mtd0, mtd1, mtd2, mtd3, > mtd4. Only mtd4 has UBI/UBIFS on top. Is it possible that some flash > handling problems in UBIFS (mtd4) "spill over" other non-UBIFS mtd > partitions? May be. Start with validating your MTD driver using MTD tests. This may help you to narrow down the problem. > 4. Other than minimizing flash writes, is there any other suggestion on > what to do to improve on the failure rate I see in the file system? Not sure. You should carefully investigate you problems and find out the nature of the failures, and then we can discuss that. -- Best Regards, Artem Bityutskiy (Артём Битюцкий)