On Wed, Nov 29, 2006 at 10:25:07AM +0000, Steven Whitehouse wrote:
quoted text
> I agree that this is a good plan, but I'd been looking at this idea from
> a different direction recently. The in kernel NFS server calls
> vfs_getattr from its filldir routine for readdirplus and this means not
> only are we unable to optimise performance by (for example) sorting
> groups of getattr calls so that we read the inodes in disk block order,
> but also that its effectively enforcing a locking order of the inodes on
> us too. Since we can have async locking in GFS2, we should be able to do
> "lockahead" with readdirplus too.
> 
> I had been considering proposing a readdirplus export operation, but
> since this thread has come up, perhaps a file operation would be
> preferable as it could solve two problems with one operation?

Doing this as an export operation is wrong.  Even if it's only used
for nfsd for now the logical level this should be on are the file operations.
If you do it you could probably prototype a syscall for it aswell - once
we have the infrastructure the syscall should be no more than about 20
lines of code.
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