From owner-freebsd-arch@FreeBSD.ORG Wed Nov 19 22:15:36 2014 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 29AD1675; Wed, 19 Nov 2014 22:15:36 +0000 (UTC) Received: from dmz-mailsec-scanner-4.mit.edu (dmz-mailsec-scanner-4.mit.edu [18.9.25.15]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A7D25E06; Wed, 19 Nov 2014 22:15:34 +0000 (UTC) X-AuditID: 1209190f-f79cb6d000005422-54-546d1552ba61 Received: from mailhub-auth-3.mit.edu ( [18.9.21.43]) (using TLS with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by dmz-mailsec-scanner-4.mit.edu (Symantec Messaging Gateway) with SMTP id B5.87.21538.2551D645; Wed, 19 Nov 2014 17:10:26 -0500 (EST) Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) by mailhub-auth-3.mit.edu (8.13.8/8.9.2) with ESMTP id sAJMAPZi006095; Wed, 19 Nov 2014 17:10:26 -0500 Received: from multics.mit.edu (system-low-sipb.mit.edu [18.187.2.37]) (authenticated bits=56) (User authenticated as kaduk@ATHENA.MIT.EDU) by outgoing.mit.edu (8.13.8/8.12.4) with ESMTP id sAJMAN7g001385 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Wed, 19 Nov 2014 17:10:25 -0500 Received: (from kaduk@localhost) by multics.mit.edu (8.12.9.20060308) id sAJMANhQ010243; Wed, 19 Nov 2014 17:10:23 -0500 (EST) Date: Wed, 19 Nov 2014 17:10:23 -0500 (EST) From: Benjamin Kaduk To: John Baldwin Subject: Re: suspending threads before devices In-Reply-To: <1580793.3ynJAbfVom@ralph.baldwin.cx> Message-ID: References: <201203202037.q2KKbNfK037014@svn.freebsd.org> <201411181721.56505.jhb@freebsd.org> <87FFDA99-ADDC-4F56-A3E8-56CCAA544542@bsdimp.com> <1580793.3ynJAbfVom@ralph.baldwin.cx> User-Agent: Alpine 1.10 (GSO 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrCIsWRmVeSWpSXmKPExsUixCmqrRskmhticOuSoMXs6dOYLPYeuc7s wOQx49N8lgDGKC6blNSczLLUIn27BK6MS1uWsRTsYK34tfA2ewPjSpYuRk4OCQETicvHjzJD 2GISF+6tZ+ti5OIQEpjNJHFuylomCGcjo8Tb55fZQKqEBA4xSdw5mgGRaGCU2HL6Hlg7i4C2 xJftLUwgNpuAisTMNxuBGjg4RASUJKZ+UwMJMwtYSixdcJ4RxBYW0JOYemcrmM0pYCQx4/Ez VhCbV8BRomnaSmaI+dsYJQ5fXw1WJCqgI7F6/xQWiCJBiZMzn7BADNWSWD59G8sERsFZSFKz kKQWMDKtYpRNya3SzU3MzClOTdYtTk7My0st0jXRy80s0UtNKd3ECA5QSf4djN8OKh1iFOBg VOLhffE2O0SINbGsuDL3EKMkB5OSKG/Er5wQIb6k/JTKjMTijPii0pzU4kOMEhzMSiK87Jy5 IUK8KYmVValF+TApaQ4WJXHeTT/4QoQE0hNLUrNTUwtSi2CyMhwcShK8t4WBGgWLUtNTK9Iy c0oQ0kwcnCDDeYCG24mADC8uSMwtzkyHyJ9i1OVoaXrbyyTEkpeflyolzqsEUiQAUpRRmgc3 B5ZYXjGKA70lzMsBUsUDTEpwk14BLWECWjJnQybIkpJEhJRUA2OJ/a2kzfcY4zXWC69c7Ljf /Evbdp7frmm/HDv0BIz12qqZa2Y+Ozzz0IfuF56zn9SpTF7z9JzzrOmSMpP5WD8zfjwreUK4 dct7Qzs1QzFxrfo/aVdPMmg9e/+h58yU1xumP9Jr/WzI6m8nl8DOo7g36MVlb4PilJ8/Jz5/ GvXYQvXmKjnLmFlKLMUZiYZazEXFiQAay9zUBwMAAA== Cc: "freebsd-arch@freebsd.org" X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Nov 2014 22:15:36 -0000 On Wed, 19 Nov 2014, John Baldwin wrote: > Yes, there should have been quotes around unmount. I want a > VFS_SUSPEND/VFS_RESUME that for local filesystems (e.g. UFS) does the on-disk > equivalent of unmount. (Flush dirty buffers and mark filesystem as clean.) > You really want this for S4 and even for S3 so you don't have to fsck if > resume fails. BTW, I think for network or userland filesystems you just punt > on this (i.e. VFS_SUSPEND is a no-op or best-effort at most) Well, some network filesystems have things that could be done in this vein, but that would have to be at the filesystem layer, not in the VFS, I think. (E.g., OpenAFS has "disconnected mode".) -Ben