From owner-freebsd-fs@freebsd.org Tue Apr 12 19:19:53 2016 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0F304B0DA3C for ; Tue, 12 Apr 2016 19:19:53 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id F3F9117C7 for ; Tue, 12 Apr 2016 19:19:52 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id u3CJJqZs045404 for ; Tue, 12 Apr 2016 19:19:52 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-fs@FreeBSD.org Subject: [Bug 208691] "panic: ffs_valloc: dup alloc" as soon as UFS root partition is mounted Date: Tue, 12 Apr 2016 19:19:53 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 10.2-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: mckusick@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-fs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Apr 2016 19:19:53 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D208691 --- Comment #3 from Kirk McKusick --- To your question of recovering when you have a corrupted root filesystem, t= hat is not a problem because the kernel always comes up with the root filesystem read-only. The panics that you can get will only happen when attempting to write the filesystem. So if you are single-user, you will have the opportun= ity to fix the filesystem while it is mounted read-only. It only switches to read-write as it exits single-user and goes to multi-user. The long-term fix is to note in the superblock when the filesystem has pani= c'ed and to force a full fsck when finding this flag set. This is part of a bigg= er project that reduces the number of panics in the filesystem that should be coming in over the next year. As a general rule, you should run with write cache disabled if you want full recoverability after a crash. --=20 You are receiving this mail because: You are the assignee for the bug.=