Date: Mon, 22 Feb 1999 06:28:56 -0800 From: Don Lewis <Don.Lewis@tsc.tdk.com> To: Terry Lambert <tlambert@primenet.com>, dfr@nlsystems.com (Doug Rabson) Cc: dillon@apollo.backplane.com, freebsd-hackers@FreeBSD.ORG Subject: Re: Panic in FFS/4.0 as of yesterday Message-ID: <199902221428.GAA28942@salsa.gv.tsc.tdk.com> In-Reply-To: Terry Lambert <tlambert@primenet.com> "Re: Panic in FFS/4.0 as of yesterday" (Feb 20, 10:52pm)
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On Feb 20, 10:52pm, Terry Lambert wrote: } Subject: Re: Panic in FFS/4.0 as of yesterday } > If it works, then changing lookup to not require locks on both vnodes at } > the same time would be a good thing. One of the reasons that NFS doesn't } > have proper node locks is that a dead NFS server can lead to a hung } > machine though a lock cascade from the NFS mount point. I suggested doing something like this, but only at mount points, which should be sufficient to fix the NFS problem. The only race conditions that would open would be for things you probably don't want to do at mountpoints anyway. } The correct way to do this, IMO, is a back-off/retry, which would } unlock the lock and queue the operation for retry, which would } reacquire the lock. Wouldn't you have to relock the parent before unlocking the lock (nasty because it reverses the locking order and might cause a deadlock). To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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