From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC556C433EF for ; Tue, 22 Feb 2022 19:16:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235185AbiBVTQp (ORCPT ); Tue, 22 Feb 2022 14:16:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235165AbiBVTQo (ORCPT ); Tue, 22 Feb 2022 14:16:44 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 294C715E6D4 for ; Tue, 22 Feb 2022 11:16:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645557377; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=T+GUkN0EwP3DJ0lx9lCnDa6Z8wiaRvOcLwpTDRLmnnU=; b=QDE01n6CkBFxaItVWG1/DbMwfd5kGbcGZR/Tcsxu59AzzdfIElWamAJJeJF8os3OjEc2ES JBQZFdwXthhHnLn66Y/nTp5lCkeMmCsmu9Fx6DWAqD5uvLt8rgor9cvwLZV30eMNj9w0kQ 7n1x06ohFnJ+Ik4mQBmmERPJwGurSKI= Received: from mail-qv1-f69.google.com (mail-qv1-f69.google.com [209.85.219.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-253-cx6FFd5PO0ObXeseIhVUtw-1; Tue, 22 Feb 2022 14:16:16 -0500 X-MC-Unique: cx6FFd5PO0ObXeseIhVUtw-1 Received: by mail-qv1-f69.google.com with SMTP id if3-20020a0562141c4300b0043147d6bacdso731165qvb.13 for ; Tue, 22 Feb 2022 11:16:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=T+GUkN0EwP3DJ0lx9lCnDa6Z8wiaRvOcLwpTDRLmnnU=; b=NVNOCl28Ta3zisF+0vl91db500915E5gaFIg5CGFzXBsEHUaXIrmGU6XBrIDlioTwU nUeYUIP/AmE5VMa/BbeNRv83QIdLKXy8ZZ1B6KUqKni7BJD0Ns3WCOPdXx10tQ93+Fty 1i4fv1Yo50SmuINs3Cs2/n+ltGF/Crq1+52JwooN0JyCeJZdrcwi7XpEBHL+r3OEg+XE F0TYlg8o706T25ZdpTZaKIICapIq72SGA/g62qOL+ipVLrfqD335wTW50HocxPlZX1JU B5+iu9GYJrg3bBd5JCe9p2DZZX4u6BWUWAust+8czCACqu/K964/EFc1DZPA9asb2WD8 XuRA== X-Gm-Message-State: AOAM53180zbV9P/BlIWkkukBqnOOuQA1txeFFhKCW5n6pWnBO4yuwNrO uvPYsU/hbMYB8TbbBJChL3M7frbB1+03MAusfRvpRRoJMYaEyaEQvi/0NIDr/0sdueOlMiH5QBW 0PPFlwjt4fS3V2nCAk/NQweM= X-Received: by 2002:a37:8602:0:b0:62c:de8f:ad74 with SMTP id i2-20020a378602000000b0062cde8fad74mr13357246qkd.142.1645557375261; Tue, 22 Feb 2022 11:16:15 -0800 (PST) X-Google-Smtp-Source: ABdhPJyoqR48S+c52tioZfwhQpWLjHci5jUdhUMN36vrY1CYw/3YuAqGThC/L/gVEu0PVsn1GFntaQ== X-Received: by 2002:a37:8602:0:b0:62c:de8f:ad74 with SMTP id i2-20020a378602000000b0062cde8fad74mr13357235qkd.142.1645557375068; Tue, 22 Feb 2022 11:16:15 -0800 (PST) Received: from localhost (pool-68-160-176-52.bstnma.fios.verizon.net. [68.160.176.52]) by smtp.gmail.com with ESMTPSA id b14sm426205qtk.44.2022.02.22.11.16.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Feb 2022 11:16:14 -0800 (PST) Date: Tue, 22 Feb 2022 14:16:13 -0500 From: Mike Snitzer To: Christoph Hellwig Cc: Brian Geffon , Alasdair Kergon , dm-devel@redhat.com, LKML Subject: Re: dm: introduce a DM_ENFORCE_OPEN_COUNT flag. Message-ID: References: <20220125002025.GA21887@agk-cloud1.hosts.prod.upshift.rdu2.redhat.com> <20220126192234.572058-1-bgeffon@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 02 2022 at 9:42P -0500, Christoph Hellwig wrote: > Withmy block hat on: nak to this. No block driver has any business at > all rejecting "too many openers". In fact any opener but the first of > a partition is already not counted as an opener, and I plan to complete > hide the open count from the device driver. I agree that this proposal exposes controls to userspace that simply shouldn't be meaningful given the arbitrary nature of openers. And preventing openers can result in a race where systemd or some other service opens before the intended primary consumer of the device. Seriously brittle and even if finely tuned to have a suitable value for some niche usecase like android: an absolute hack. Sorry, not interested in taking this.