From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: bit flip From: David Woodhouse To: catboat@texas.net In-Reply-To: <1191439970.4703ee62083f1@webmail.texas.net> References: <1191439970.4703ee62083f1@webmail.texas.net> Content-Type: text/plain Date: Wed, 10 Oct 2007 00:48:17 -0400 Message-Id: <1191991698.578.92.camel@localhost.localdomain> Mime-Version: 1.0 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: , On Wed, 2007-10-03 at 14:32 -0500, catboat@texas.net wrote: > A NAND card flipped a bit and caused a data CRC problem in a data node. > When I cat the file, this region is zeroes. cat exits with rc 0. On NAND you should have ECC to prevent this failure mode. > I can simulate this. I made a jffs2 file system using mkfs.jffs2. > In a file with multiple data nodes, I manually flip a bit in one of them. > At mount time, I see a printk about it. cat exits with 0 and the file has a > chunk of zeroes in it. > > Seems incorrect to me. I expected jffs2 to return EIO somewhere. > > Does it seem incorrect to you? We could probably manage that -- there should never be any _holes_ in the file. It's not a panacea though, because sometimes if the latest node is corrupted you might just see 'old' dirty data from an earlier version, rather than a hole. -- dwmw2