From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from a2s40.a2hosting.com ([74.126.24.200]) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1O40lr-0007iD-OT for linux-mtd@lists.infradead.org; Mon, 19 Apr 2010 23:52:56 +0000 Message-ID: <4BCCECC7.8000006@fosstel.com> Date: Mon, 19 Apr 2010 19:52:39 -0400 From: "Pedro I. Sanchez" MIME-Version: 1.0 To: twebb Subject: Re: UBIFS and MLC NAND Flash References: <4BA7A183.7040206@fosstel.com> <1270714961.6754.107.camel@localhost> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org, dedekind1@gmail.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , twebb wrote: >>> 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. >> >> > > Pedro, > I'm seeing very similar issues with MLC+UBIFS, though not only with > read-only files. Have you made any progress in your investigation or > while trying Artem's suggestions? I'm about to start digging into > this and would be interested to hear about any issues you may have > come across. Do you have any opinion on whether this "corruption" is > related to the information posted on the linux-mtd site at... > http://www.linux-mtd.infradead.org/faq/ubifs.html#L_ubifs_mlc ? > > A few notes: > - I do occasionally have power cuts, but my understanding was that > UBI/UBIFS was very tolerant of that condition. > - I use CONFIG_MTD_UBI_WL_THRESHOLD=256 > - I'm using linux-2.6.29 > > Thanks, > twebb I haven't had the opportunity to use 2.6.29 with the ubifs backport yet. However, I run my devices over an extended operational test and couldn't reproduce the errors. In this test I avoided any power cuts on purpose because I wanted to verify that the boards' software was not at fault during normal conditions. I still see the errors in the deployed boards and these ones are subject to random power cuts. After analyzing the logs I conclude that there is a strong correlation between the power cuts and the corruption errors. The typical scenario is a board running fine for two months without interruption, then a power cut, and then upon reboot a myriad of UBIFS error messages show up (see sample following my signature) I'm almost convinced now that power cuts are the culprit. I will be conducting test in the next few days to fully verify this. I'll post my results. Thanks, -- Pedro Mar 16 00:58:22 blazepoint kernel: uncorrectable error : <3>UBI error: ubi_io_re ad: error -74 while reading 2560 bytes from PEB 376:213720, read 2560 bytes Mar 16 00:58:22 blazepoint kernel: UBIFS error (pid 1507): try_read_node: cannot read node type 1 from LEB 322:209624, error -74 Mar 16 00:58:22 blazepoint kernel: uncorrectable error : <3>UBI error: ubi_io_re ad: error -74 while reading 2560 bytes from PEB 376:213720, read 2560 bytes Mar 16 00:58:22 blazepoint kernel: UBIFS error (pid 1507): ubifs_check_node: bad CRC: calculated 0x5edaa128, read 0xacfe20eb Mar 16 00:58:22 blazepoint kernel: UBIFS error (pid 1507): ubifs_check_node: bad node at LEB 322:209624 Mar 16 00:58:22 blazepoint kernel: UBIFS error (pid 1507): ubifs_read_node: expe cted node type 1 Mar 16 00:58:22 blazepoint kernel: UBIFS error (pid 1507): do_readpage: cannot r ead page 261 of inode 3463, error -117 Mar 16 00:58:22 blazepoint kernel: uncorrectable error : <3>UBI error: ubi_io_re ad: error -74 while reading 2560 bytes from PEB 376:213720, read 2560 bytes