From: Eric Sandeen Subject: Re: Mentor for a GSoC application wanted (Online ext2/3 filesystem checker) Date: Tue, 22 Apr 2008 12:02:55 -0500 Message-ID: <480E1A3F.9030103@redhat.com> References: <20080419012952.GE25797@mit.edu> <20080419185603.GA30449@mit.edu> <480A42F6.2030005@redhat.com> <804dabb00804220954s67d56cacj89098d88697565aa@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Theodore Tso , Alexey Zaytsev , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, Rik van Riel To: Peter Teoh Return-path: In-Reply-To: <804dabb00804220954s67d56cacj89098d88697565aa@mail.gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Peter Teoh wrote: > On Sun, Apr 20, 2008 at 3:07 AM, Eric Sandeen wrote: >> Theodore Tso wrote: >> > On Sat, Apr 19, 2008 at 01:44:51PM +0400, Alexey Zaytsev wrote: >> >> If it is a block containing a metadata object fsck has already read, >> >> than we already know what kind of object it is (there must be a way >> >> to quickly find all cached objects derived from a given block), and >> >> can update the cached version. And if fsck has not yet read the >> >> block, it can just be ignored, no matter what kind of data it >> >> contains. If it contains metadata and fsck is intrested in it, it >> >> will read it sooner or later anyway. If it contains file data, why >> >> should fsck even care? >> >> It seems to me that what the proposed project really does, in essence, >> is a read-only check of a filesystem snapshot. It's just that the >> snapshot is proposed to be constructed in a complex and non-generic (and >> maybe impossible) way. >> >> If you really just want to verify a snapshot of the fs at a point in >> time, surely there are simpler ways. If the device is on lvm, there's >> already a script floating around to do it in automated fasion. (I'd >> pondered the idea of introducing META_WRITE (to go with META_READ) and >> maybe lvm could do a "metadata-only" snapshot to be lighter weight?) >> > > Can I know where is this script? Or if u cannot locate it, does it > have any resemblance to all the stuff mentioned below?. Google for "lvcheck" and find it buried in a thread "forced fsck (again?)" on the ext3-users list - I'm not sure if it has an upstream home anywhere yet... -Eric