NFS client broken in Linus' tip

On Feb 3, 2014, at 9:57, Christoph Hellwig [off-list ref] wrote:

On Mon, Feb 03, 2014 at 09:17:30AM -0500, Trond Myklebust wrote:

quoted

As I said above, that causes posix_acl_xattr_get() to return the wrong answer (ENODATA instead of EOPNOTSUPP).

Is it really the wrong answer?  How does userspace care wether this
server doesn't support ACLs at all or none is set?  The resulting
behavior is the same.

It will certainly cause acl_get_file() to behave differently than previously. I?ve no idea how that will affect applications, though.

If there's a good reason to care we might have to go with your patch,
but if we can avoid it I'd prefer to keep things simple.

One alternative is to simply wrap posix_acl_xattr_get() in fs/nfs/nfs3acl.c, and have it check the value of nfs_server_capable(inode, NFS_CAP_ACLS) before returning ENODATA. That?s rather ugly too...

--
Trond Myklebust
Linux NFS client maintainer