Date: Thu, 24 Aug 2000 07:00:15 -0700 (PDT) From: Robert Watson <rwatson@FreeBSD.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/20804: deadlocking when using vnode disk file and quotas Message-ID: <200008241400.HAA79917@freefall.freebsd.org>
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The following reply was made to PR kern/20804; it has been noted by GNATS. From: Robert Watson <rwatson@FreeBSD.org> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: freebsd-gnats-submit@FreeBSD.org, Sheldon Hearn <sheldonh@uunet.co.za> Subject: Re: kern/20804: deadlocking when using vnode disk file and quotas Date: Thu, 24 Aug 2000 09:56:34 -0400 (EDT) On Thu, 24 Aug 2000, Poul-Henning Kamp wrote: > In message <Pine.NEB.3.96L.1000824093709.31571B-100000@fledge.watson.org>, Robe > rt Watson writes: > > > >Poul-Henning, > > > >Do you have a chance to look at this bug, which was raised on -fs > >recently? It has to do, I believe, with a recursive lock/deadlock issue > >relating to the md device and the UFS quota implementation, presumably a > >lock ordering issue relating to the md device vnode lock and the vnode > >lock for the quota data file on that file system. I haven't had a chance > >to look much further, and apparently it mostly manifests in jail (I'm not > >sure I understand why that might be the case -- possibly having to do with > >the starting point (root) for recursive name lookups with lock requests). > > No I haven't even looked at it. The jail stuff doesn't even know > what a lock is, much less touch one, so the jail involvement was > not enough to make me put it on my busy schedule... My impression was that the bug had more to do with "md" -- is md yours, or someone else's? The reason I'm looking at the jail issue is that that's how the reporter of the bug described it. The interaction with jail() has to do with chroot() and recursive name lookup and locking: when a process is jailed, the name lookup, and hence tree walking and lock handling, starts at a different point in the tree, probably with a root in the md file system, which could affect the locking issues. Robert N M Watson robert@fledge.watson.org http://www.watson.org/~robert/ PGP key fingerprint: AF B5 5F FF A6 4A 79 37 ED 5F 55 E9 58 04 6A B1 TIS Labs at Network Associates, Safeport Network Services To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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