From owner-freebsd-questions@FreeBSD.ORG Thu May 31 13:16:13 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 187951065672 for ; Thu, 31 May 2012 13:16:13 +0000 (UTC) (envelope-from wblock@wonkity.com) Received: from wonkity.com (wonkity.com [67.158.26.137]) by mx1.freebsd.org (Postfix) with ESMTP id C8CD58FC1E for ; Thu, 31 May 2012 13:16:12 +0000 (UTC) Received: from wonkity.com (localhost [127.0.0.1]) by wonkity.com (8.14.5/8.14.5) with ESMTP id q4VDG9rf082291; Thu, 31 May 2012 07:16:09 -0600 (MDT) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.14.5/8.14.5/Submit) with ESMTP id q4VDG965082288; Thu, 31 May 2012 07:16:09 -0600 (MDT) (envelope-from wblock@wonkity.com) Date: Thu, 31 May 2012 07:16:09 -0600 (MDT) From: Warren Block To: Polytropon In-Reply-To: <20120531134636.e070cef2.freebsd@edvax.de> Message-ID: References: <546749752.20120531141933@zhigulinet.ru> <20120531134636.e070cef2.freebsd@edvax.de> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (wonkity.com [127.0.0.1]); Thu, 31 May 2012 07:16:09 -0600 (MDT) Cc: dmitry@zhigulinet.ru, freebsd-questions@freebsd.org Subject: Re: fsck on a mounted fs as read-only X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 31 May 2012 13:16:13 -0000 On Thu, 31 May 2012, Polytropon wrote: > On Thu, 31 May 2012 14:19:33 +0400, dmitry@zhigulinet.ru wrote: >> Good afternoon. >> Could not tell whether you can run fsck on checking mounted >> file system as read-only, if prior to that with which the parameters >> >> >> ftp # mount >> ... >> / dev/aacd0 on / var / ftp (ufs, NFS exported, local, read-only) >> >> Launched with these parameters and this is what gives >> >> ftp # fsck -yf / dev/aacd0 >> ** / Dev/aacd0 (NO WRITE) >> ** Last Mounted on / var / ftp >> ** Phase 1 - Check Blocks and Sizes >> >> As I understand it does not fix the fsck filesystem. > > Correct. For file system modifications the file system may not > be mounted because "lower level operations" maybe will take > place. In your current setting, only checks will be performed, > but _if_ something needs to be modified, it will not happen. > The reason: It _might_ affect the file system to change, even > if it's "just" in read-only state. > > Solution: Unmount the file system and re-run fsck. fsck(8) can work on filesystems mounted read only. If, say, graphics/cairo causes X to crash the machine, rebooting into single-user mode and running # fsck -y -t ufs will clean up the read-only mounted / also. Agreed that this should be avoided if possible, but sometimes it is necessary.