From mboxrd@z Thu Jan 1 00:00:00 1970 From: Piergiorgio Sartor Subject: Re: Why does one get mismatches? Date: Fri, 19 Feb 2010 16:18:09 +0100 Message-ID: <20100219151809.GB4995@lazy.lzy> References: <869541.92104.qm@web51304.mail.re2.yahoo.com> <4B67451F.8040206@tmr.com> <20100202093738.44b4fece@notabene.brown> <4B684087.50001@tmr.com> <20100211161444.7a0ea7bb@notabene.brown> <20100211175133.GA30187@atlantis.cc.ndsu.nodak.edu> <4B7B0D45.7040801@tmr.com> <6db64f7872286165ac1fd3436e9d6476@localhost> <20100218100547.7aecdc34@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20100218100547.7aecdc34@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: Steven Haigh , Bill Davidsen , Bryan Mesich , Jon@eHardcastle.com, linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi, > When memory changes between being written to one device and to another, this > does not cause corruption, only inconsistency. Either the block will be > written again consistently soon, or it will never be read. well, is this for sure? I mean, by design of the md subsystem. Or it is like that because we trust the filesystem? And why it is like that? Why not to use the good old readers-writer mechanism to make sure all blocks are the same, when they're are written (namely lock). It seems to me, maybe I'm wrong, not a so safe design. I assume, it should not be possible to cause this situation, unless there is a crash or a bug in the md layer. What if a new filesystem will write a block, changing on the fly, i.e. during RAID-1 writes, and then, later, reading this block again? It will get, maybe, not the correct data. In other words, would it be better, for the md layer, to be robust against these kind of threats? bye, -- piergiorgio