Date: Tue, 17 Aug 1999 23:18:06 +0900 (JST) From: Michael Hancock <michaelh@cet.co.jp> To: Terry Lambert <tlambert@primenet.com> Cc: wrstuden@nas.nasa.gov, Matthew.Alton@anheuser-busch.com, Hackers@FreeBSD.ORG, fs@FreeBSD.ORG Subject: Re: BSD XFS Port & BSD VFS Rewrite Message-ID: <Pine.BSF.3.95LJ1.1b3.990817224323.17508B-100000@sv01.cet.co.jp> In-Reply-To: <199908170231.TAA08526@usr02.primenet.com>
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> > I'm not familiar with the VFS_default stuff. All the vop_default_desc > > routines in NetBSD point to error routines. > > In FreeBSD, they now point to default routines that are *not* error > routines. This is the problem. I admit the change was very well > intentioned, since it made the code a hell of a lot more readable, > but choosing between readable and additional function, I take function > over form (I think the way I would have "fixed" the readability is by > making the operations that result in the descriptor set for a mounted > FS instance be both discrete, and named for their specific function). As I recall most of FBSD's default routines are also error routines, if the exceptions were a problem it would would be trivial to fix. I think fixing resource allocation/deallocation for things like vnodes, cnbufs, and locks are a higher priority for now. There are examples such as in detached threading where it might make sense for the detached child to be responsible for releasing resources allocated to it by the parent, but in stacking this model is very messy and unnatural. This is why the purpose of VOP_ABORTOP appears to be to release cnbufs but this is really just an ugly side effect. With stacking the code that allocates should be the code that deallocates. Substitute, "code" with "layer" to be more correct. I fixed a lot of the vnode and locking cases, unfortunately the ones that remain are probably ugly cases where you have to reacquire locks that had to be unlocked somewhere in the executing layer. See VOP_RENAME for an example. Compare the number of WILLRELEs in vnode_if.src in FreeBSD and NetBSD, ideally there'd be none. Regards, Mike Hancock To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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