From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx.dave-tech.it ([88.37.112.223]) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1JKwRY-0001av-BL for linux-mtd@lists.infradead.org; Fri, 01 Feb 2008 14:01:11 +0000 Message-ID: <47A32600.9000807@dave-tech.it> Date: Fri, 01 Feb 2008 15:00:32 +0100 From: llandre MIME-Version: 1.0 To: "Korolev, Alexey" , mattjreimer@gmail.com, jamie@shareable.org Subject: Re: JFFS2: file contents in case of data CRC error References: <47A1FD3F.2020102@dave-tech.it> <523F3D8D8C97554AA47E53DF1A05466A01880831@nnsmsx411.ccr.corp.intel.com> In-Reply-To: <523F3D8D8C97554AA47E53DF1A05466A01880831@nnsmsx411.ccr.corp.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Alexey, Matt and Jamie, thank you all for the precious information. > Could you please give information about how you can get this error? I > need to know use case. The issue has been reported by a customer working on PPC405EP-based system running linux 2.4.20. The device under test has run a temperature cycle test. The temperature has been varied in the whole industrial range (-40/+85 deg C). After completing the test, the files stored on NAND have been read back and compared to the original ones - written on NAND before starting the temperature test - and the difference in the file f.img previously described arose. >> to NAND. In fact, in the middle of the file, I see a 4-kByte "hole" >> where all bytes are 0. > > It is Ok. NAND error correction could return that data is correct even > if it is not correct. It finds the issues with guarantee only in case of > 1 or 2 bits errors. About this point I agree with catboat (http://article.gmane.org/gmane.linux.drivers.mtd/19463). In my opinion in this case JFFS2 should report an error code != 0 in order to warn the userland that something did not work perfectly. >> bash-2.05# mount -t jffs2 -o ro /dev/mtdblock0 /mnt/nand0 >> mtdblock_open >> ok >> bash-2.05# cp -v /mnt/nand0/f.img /tmp/ >> jffs2_get_inode_nodes(): Data CRC failed on node at 0x01d55544: Read >> 0x80b8997f, calculated 0x57f0ea8e >> `/mnt/nand0/f.img' -> `/tmp/f.img' > > This is a bad error! How obtained you this? What you did before getting > this? See previous description. -- llandre DAVE Electronics System House - R&D Department web: http://www.dave.eu email: r&d2@dave-tech.it