From: JP Abgrall Subject: Re: [PATCH] ext4: Add support for SFITRIM, an ioctl for secure FITRIM. Date: Tue, 17 Jun 2014 10:35:50 -0700 Message-ID: References: <20140613031538.GR4453@dastard> <20140613033029.GS4453@dastard> <20140613050703.GT4453@dastard> <20140613142054.GA23180@thunk.org> <20140613143157.GB23180@thunk.org> <20140613234134.GC5036@thunk.org> <20140617024953.GG9508@dastard> <20140617124629.GA13868@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "Theodore Ts'o" , Dave Chinner , Eric Sandeen , linux-ext4@vger.kernel.org, Geremy Condra , "linux-fsdevel@vger.kernel.org" To: =?UTF-8?B?THVrw6HFoSBDemVybmVy?= Return-path: In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Jun 17, 2014 at 6:00 AM, Luk=C3=A1=C5=A1 Czerner wrote: > > What is the difference between -o discard mount option ? Android will not mount -o discard because of the overall penalty. > I guess > that this way you can do it selectively on certain files, but I > wonder how useful it is going to be anyway ? =46or certain files only. Useful enough. > If they are ok with only best effort, then we can have FISTRIM ioctl > which would use the same internal file system functionality as > FITRIM but we would add a flag to be able to call sb_issue_discard() > with BLKDEV_DISCARD_SECURE flag, I think this was the idea of the original patch. > disable the optimization to skip > already discarded groups and call sync on the file system before we > start doing any actuall work. That would need adding to the original patch. > If we do this though we should not add word "security" anywhere for > the use to see :) We can live with that. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html