From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Can we please make 'allow_discards' the default for dm-crypt? Date: Tue, 13 Sep 2016 19:10:42 -0700 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Alasdair Kergon , Mike Snitzer Cc: "dm-devel@redhat.com" , Herbert Xu List-Id: dm-devel.ids I really detest our current dm-crypt policy of not allowing discard by default. It has this silly "but but security" reason behind it, but let's face it: if you don't want to do discards for security reasons, then JUST DON'T DO THEM. Or add a "no_discards" option. Because right now, the default behavior is wrong. It's geared toward the 0.1% crazy-anal people, and making a *default* option for those people is just silly. The whole argument that "you can see access patterns and how much free space there is" is just complete bullshit. It's not what any sane person would care about. The rest of us just want to encrypt our data on our laptops in case they get stolen, and we don't want to not be able to do the occasional "fstrim". Yes, good flash doesn't need trimming all that much, but it won't hurt. And right now we penalize people who want to do the sane good thing. Sure, we could say that distros should just add the "allow_discard" flag instead, and maybe have a checkbox to say "are you a crazy anal person" along with the "encrypt disk" checkbox. But EVEN IF the distro were to do that, that doesn't mean that the kernel default should be the wrong way around. Comments? Linus