From owner-freebsd-questions@FreeBSD.ORG Sat Apr 28 17:52:03 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 B2FB7106564A for ; Sat, 28 Apr 2012 17:52:03 +0000 (UTC) (envelope-from aimass@yabarana.com) Received: from mail-iy0-f182.google.com (mail-iy0-f182.google.com [209.85.210.182]) by mx1.freebsd.org (Postfix) with ESMTP id 773B58FC14 for ; Sat, 28 Apr 2012 17:52:03 +0000 (UTC) Received: by iahk25 with SMTP id k25so3280466iah.13 for ; Sat, 28 Apr 2012 10:52:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type :content-transfer-encoding:x-gm-message-state; bh=ALGpeWklPTVIgnIj4zaqRE0s8tqu8SAZPu9tRgCUhhY=; b=aLiMTh9TUg/znVLv1NQ1G04H6f+n6AaJ1sK1pLip9GE2T3owYEAadO4FivncbPTDql /jIJZrhaGq2hzZWZ1Wuq6jE7+F1gYc8oqaRFgLRLsH0kIvDAlo5JSLQsfkcIImLWjqwf nPKEkLAECyumGWjEMISIDMXex4IVdkBJ+PwTL5gaG0aGsVVN27uMe6DPWaQ376kPsNL1 Iz7+acCJJaHDbXHyMGe27AwH+u0MitnwchSvnKgCJhIt8R+zWnc62P9+ACH0vhPU7bCF sjfrwHi3UYqhFnTIGrlXLh66FimGzxOss5Xdke5an3ziItz56RmiWkJ/VEcAcN3RX+c6 8AXg== MIME-Version: 1.0 Received: by 10.50.197.233 with SMTP id ix9mr6230907igc.26.1335635522860; Sat, 28 Apr 2012 10:52:02 -0700 (PDT) Sender: aimass@yabarana.com Received: by 10.231.74.138 with HTTP; Sat, 28 Apr 2012 10:52:02 -0700 (PDT) In-Reply-To: <201204281731.q3SHVaiM061997@mail.r-bonomi.com> References: <201204281731.q3SHVaiM061997@mail.r-bonomi.com> Date: Sat, 28 Apr 2012 13:52:02 -0400 X-Google-Sender-Auth: 3TdgvcRn2FxmUbjhX91rw9DYIug Message-ID: From: Alejandro Imass To: freebsd-questions@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Gm-Message-State: ALoCoQmTxT/9ZsOh0Laxk4OBDxQI8ZriRH/XNmTO1khGHMW5OyvFXAvHwt9dFOLlTZTI1yG+ywMI Subject: Re: UFS Crash and directories now missing 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: Sat, 28 Apr 2012 17:52:03 -0000 On Sat, Apr 28, 2012 at 1:31 PM, Robert Bonomi w= rote: > > Alejandro Imass wrote: >> On Sat, Apr 28, 2012 at 11:39 AM, Robert Bonomi >> wrote: >> > =A0Alejandro Imass wrote: >> >> After a little more research, ___it it NOT unlikely at all___ that >> >> under high distress and a hard boot, UFS could have somehow corrupted >> >> the directory structure, whilst maintaining the data intact. >> > >> > This is techically accurate, *BUT* the specifics of the quote "corrupt= ion" >> > unquote in the case under discussion make it *EXTREMELY* unlikely that= this >> > is what happened. >> > >> > 99.99+++% of all UFS filesystem "corruption' issues are the result of = a >> > system crash _between_ the time cached 'meta-data' is updated in memor= y >> > and that data is flushed to disk (a deferred write). >> > >> > The second most common (and vanishingly rare) failure mode is a powerf= ail >> > _as_ a sector of disk is being written -- resulting in 'garbage data' >> > being written to disk. >> > >> > The next possibility is 'cosmic rays'. =A0If running on 'cheap' hardwa= re >> > (i.e., without 'ECC' memory), this can cause a *SINGLE-BIT* error in >> > data being output. >> > >> > The fact that the 'corrupted' filesystem passed fsck -without- any rep= orted >> > errors shows that everything in the filesystem meta-data was consisten= t >> > >> [...] >> >> > I think it is safe to conclude that the probabilities -greatly- favor >> > alternative #1. >> > >> >> OK. So after your comments and further research I concur with you on >> the mv but if it wasn't a human, then this might be exposing a serious >> security flaw in the jail system or the way EzJail implements it. > > BOGON ALERT!!! > I admit my ignorance on how the filesystem works but I don't think your condescending remarks add a lot of value. The issue here is this actually happened and there is a flaw somewhere other than "the stupid administrator did it".