Re: [PATCH 6/6] nfs: disable leases over NFS

["J. Bruce Fields" <bfields@fieldses.org>]

On Fri, Jun 29, 2007 at 05:16:19PM -0400, Peter Staubach wrote:
> First, there is already some support to disable leases for NFS mounted
> file systems in -mm, I think.

Oops, sorry; my fault for not checking -mm before sending....

> Are you planning on removing it?

I'd rather do that, yes.  Any objection?

> Second, it seems to me that EINVAL would be a better error to return
> than EOPNOTSUPP.  This is an invalid operation to apply to this file
> and might match POSIX style specs better.

I'm not sure what you mean by "might match POSIX style specs better"?

>From a quick check, other reasons we'd get EINVAL in this case:

	- attempt to get a lease on something other than a regular file.
	- leases disabled with /proc/sys/fs/leases-enable

So if the application calling fcntl knows it was calling it on a regular
file, then with your proposal an EINVAL return would mean leases were
disabled for one reason or another, and it could take that as a sign to
fall back on some other behavior.  And I can't see any reason it would
need to distinguish between those two remaining cases (filesystem
doesn't support leases, or leases are disabled by the sysctl).  So,
OK, EINVAL sounds fine to me.

But I don't have a really strong opinion.  I think the suggestion of
EOPNOTSUPP was from Steven Whitehouse; Steven, do you care?

--b.