[Lustre-devel] Queries regarding LDLM_ENQUEUE

Andreas Dilger andreas.dilger at oracle.com
Wed Oct 20 10:30:24 PDT 2010


On 2010-10-20, at 11:13, Nicolas Williams wrote:
> Well, if we're going to add openg() (or whatever its name), we might as
> well add variants of stat() that don't require getting the size when the
> app doesn't need it

That is "stat_lite" (or various different names), and was also under discussion for adding to the Linux kernel, until it turned from being a sensible API to a Linux-designed-by-committee API from hell (IMHO, of course) and has stopped dead in its tracks.

> Another possibility is to say that a handle is only good as long as the
> original file descriptor remains open (recovery issues here), and that
> client can tell the MDS that it will be sharing its handle with other
> clients.

That is partly what the MDS open lock does.  It was intended for NFS servers to allow them to open and close a file locally for its clients w/o MDS RPCs.

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.




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