fs/9p: xattr: add trusted and security namespaces

Allow requests for security.* and trusted.* xattr name spaces
to pass through to server.

The new files are 99% cut and paste from fs/9p/xattr_user.c with the
namespaces changed.  It has the intended effect in superficial testing.
I do not know much detail about how these namespaces are used, but passing
them through to the server, which can decide whether to handle them or not,
seems reasonable.

I want to support a use case where an ext4 file system is mounted via 9P,
then re-exported via samba to windows clients in a cluster.  Windows wants
to store xattrs such as security.NTACL.  This works when ext4 directly
backs samba, but not when 9P is inserted.  This use case is documented here:
   http://code.google.com/p/diod/issues/detail?id=95

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index c45e016b190f..3c28cdfb8c47 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -167,9 +167,13 @@ ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
 
 const struct xattr_handler *v9fs_xattr_handlers[] = {
         &v9fs_xattr_user_handler,
+        &v9fs_xattr_trusted_handler,
 #ifdef CONFIG_9P_FS_POSIX_ACL
         &v9fs_xattr_acl_access_handler,
         &v9fs_xattr_acl_default_handler,
 #endif
+#ifdef CONFIG_9P_FS_SECURITY
+        &v9fs_xattr_security_handler,
+#endif
         NULL
 };