From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [PATCH] dm-raid: add RAID discard support Date: Wed, 24 Sep 2014 11:11:21 -0400 Message-ID: References: <1411491106-23676-1-git-send-email-heinzm@redhat.com> <20140924142149.GA3858@infradead.org> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140924142149.GA3858@infradead.org> (Christoph Hellwig's message of "Wed, 24 Sep 2014 07:21:49 -0700") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Christoph Hellwig Cc: Heinz Mauelshagen , device-mapper development , "Martin K. Petersen" List-Id: dm-devel.ids >>>>> "Christoph" == Christoph Hellwig writes: Christoph> - start adding a whitelist for ATA As far as I know the sanity bits have been discussed in T13 but haven't been agreed upon yet. The hard part about the whitelist is that bad things only happen in rare circumstances. However, we may be able to take some hints from here: http://www.lsi.com/downloads/Public/RAID%20Controllers/RAID%20Controllers%20Common%20Files/MegaRAID_SAS3_936x-938x_Compatibility_List.pdf Christoph> Alternatively we could get rid of discard_zeroes_data and Christoph> stop the pretence of any sane behavior from discard, and Christoph> instead expose an unmap bit through the blkdev_issue_zeroout Christoph> stack for those callers who want to do a discard, but rely on Christoph> zeroes. The end effect will be the same, just a different Christoph> presentation. Yep. -- Martin K. Petersen Oracle Linux Engineering