Date: Wed, 3 May 2006 09:54:50 +0200 (CEST) From: "Peter Holm" <peter@holm.cc> To: "Kris Kennaway" <kris@obsecurity.org> Cc: freebsd-fs@freebsd.org, Kris Kennaway <kris@obsecurity.org> Subject: Re: Stress testing the UFS2 filesystem Message-ID: <18034.193.3.141.124.1146642890.squirrel@webmail7.pair.com> In-Reply-To: <20060503072013.GA2926@xor.obsecurity.org> References: <20060502193900.GA94069@peter.osted.lan> <1541458526.20060503003229@merdin.com> <20060502221306.GD95348@xor.obsecurity.org> <44584421.3000807@cs.tu-berlin.de> <20060503072013.GA2926@xor.obsecurity.org>
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> On Wed, May 03, 2006 at 07:48:17AM +0200, Bj?rn K?nig wrote: >> Kris Kennaway schrieb: >> >On Wed, May 03, 2006 at 12:32:29AM +0400, Pavel Merdine wrote: >> >>Of course I think we could do patches to overcome corrupting panics, >> >>but the core FreeBSD team would not accept this, as they are happy >> >>with panics and corruptions they make to other filesystems. >> > >> >Of course not, don't make silly accusations :-) >> > >> >The problem is much more difficult to solve than "making the panic an >> >error return". >> >> I'm interested in more information about this issue. Do you have a >> reference to an old discussion about this topic or do you like to >> explain it a little bit further for me (and probably others)? > > See the URL that Peter provided in his original post. > > The issue that he is testing is how well the filesystem behaves when > you arbitrarily damage it and then run fsck (ideally, fsck should > detect all of the damage and repair it). He seems to have found cases > where fsck does not detect and repair the damage, leading to panics at > runtime. > Actually the filesystems mounts without any problems if fsck is run first. The objective of this exercise was to show that background fsck may lead to panics. This was a problem I saw a lot a year ago when I did some testing of patches and in the cause of a working day saw two or three panics. With background fsck I would from time to time get a secondary panic, which typically zapped the original crash dump. - Peter - Peter > You can ignore Pavel's reply since he didn't have anything to add to > the discussion :-) > > Kris > - Peter Holm
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