nfs: add client side only definitions for user xattrs

Add client-side only definitions for user extended
attributes (RFC8276). These are the access bits
as used by the client code, and the CLNT procedure
number definition.
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/nfs4.h

@@ -553,6 +553,11 @@ enum {
 	NFSPROC4_CLNT_LAYOUTERROR,
 
 	NFSPROC4_CLNT_COPY_NOTIFY,
+
+	NFSPROC4_CLNT_GETXATTR,
+	NFSPROC4_CLNT_SETXATTR,
+	NFSPROC4_CLNT_LISTXATTRS,
+	NFSPROC4_CLNT_REMOVEXATTR,
 };
 
 /* nfs41 types */

include/linux/nfs_fs.h

@@ -212,6 +212,9 @@ struct nfs4_copy_state {
 #define NFS_ACCESS_EXTEND      0x0008
 #define NFS_ACCESS_DELETE      0x0010
 #define NFS_ACCESS_EXECUTE     0x0020
+#define NFS_ACCESS_XAREAD      0x0040
+#define NFS_ACCESS_XAWRITE     0x0080
+#define NFS_ACCESS_XALIST      0x0100
 
 /*
  * Cache validity bit flags