[PATCH 1/4] nfs4.2: add nfs4_2.x to generate the UNCACHEABLE_FILE_DATA attribute

Introduce Documentation/sunrpc/xdr/nfs4_2.x for NFSv4.2 protocol
extensions and define the UNCACHEABLE_FILE_DATA attribute (attr 87)
there, verbatim from draft-ietf-nfsv4-uncacheable-files Section 7:

  typedef bool            fattr4_uncacheable_file_data;
  const FATTR4_UNCACHEABLE_FILE_DATA      = 87;

This mirrors how the sibling NFSv4.2 attributes (FATTR4_OFFLINE=83,
FATTR4_TIME_DELEG_*=84/85, FATTR4_OPEN_ARGUMENTS=86) are defined in
Documentation/sunrpc/xdr/nfs4_1.x and generated by
tools/net/sunrpc/xdrgen into <linux/sunrpc/xdrgen/nfs4_1.h>, which
nfs4.h already includes.

Wire the fs/nfsd "make xdrgen" target to generate the definitions header
<linux/sunrpc/xdrgen/nfs4_2.h> and include it from <linux/nfs4.h>, so the
generated FATTR4_UNCACHEABLE_FILE_DATA constant and the
NFS4_fattr4_uncacheable_file_data_sz size macro are available to the
NFSv4.2 client support that follows.

No functional change.

Signed-off-by: Mike Snitzer <[email protected]>
Assisted-by: Claude:claude-opus-4-8
---
 Documentation/sunrpc/xdr/nfs4_2.x    | 52 ++++++++++++++++++++++++++++
 fs/nfsd/Makefile                     |  5 ++-
 include/linux/nfs4.h                 |  1 +
 include/linux/sunrpc/xdrgen/nfs4_2.h | 19 ++++++++++
 4 files changed, 76 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/sunrpc/xdr/nfs4_2.x
 create mode 100644 include/linux/sunrpc/xdrgen/nfs4_2.h

diff --git a/Documentation/sunrpc/xdr/nfs4_2.x b/Documentation/sunrpc/xdr/nfs4_2.x
new file mode 100644
index 000000000000..d10a91d657b0
--- /dev/null
+++ b/Documentation/sunrpc/xdr/nfs4_2.x
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2026 IETF Trust and the persons identified
+ * as the document authors.  All rights reserved.
+ *
+ * The document authors are identified in RFC 7862 and
+ * draft-ietf-nfsv4-uncacheable-files.
+ *
+ * Redistribution and use in source and binary forms, with
+ * or without modification, are permitted provided that the
+ * following conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ *   copyright notice, this list of conditions and the
+ *   following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the
+ *   following disclaimer in the documentation and/or other
+ *   materials provided with the distribution.
+ *
+ * - Neither the name of Internet Society, IETF or IETF
+ *   Trust, nor the names of specific contributors, may be
+ *   used to endorse or promote products derived from this
+ *   software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
+ *   AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+ *   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ *   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
+ *   EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ *   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ *   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ *   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ *   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ *   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ *   IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ *   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+pragma header nfs4;
+
+/*
+ * The following content was extracted from
+ * draft-ietf-nfsv4-uncacheable-files
+ */
+
+typedef bool            fattr4_uncacheable_file_data;
+
+const FATTR4_UNCACHEABLE_FILE_DATA      = 87;
diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
index f0da4d69dc74..0ff198e102a3 100644
--- a/fs/nfsd/Makefile
+++ b/fs/nfsd/Makefile
@@ -37,11 +37,14 @@ nfsd-$(CONFIG_DEBUG_FS) += debugfs.o
 #
 .PHONY: xdrgen
 
-xdrgen: ../../include/linux/sunrpc/xdrgen/nfs4_1.h nfs4xdr_gen.h nfs4xdr_gen.c
+xdrgen: ../../include/linux/sunrpc/xdrgen/nfs4_1.h ../../include/linux/sunrpc/xdrgen/nfs4_2.h nfs4xdr_gen.h nfs4xdr_gen.c
 
 ../../include/linux/sunrpc/xdrgen/nfs4_1.h: ../../Documentation/sunrpc/xdr/nfs4_1.x
 	../../tools/net/sunrpc/xdrgen/xdrgen definitions $< > $@
 
+../../include/linux/sunrpc/xdrgen/nfs4_2.h: ../../Documentation/sunrpc/xdr/nfs4_2.x
+	../../tools/net/sunrpc/xdrgen/xdrgen definitions $< > $@
+
 nfs4xdr_gen.h: ../../Documentation/sunrpc/xdr/nfs4_1.x
 	../../tools/net/sunrpc/xdrgen/xdrgen declarations $< > $@
 
diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h
index 44e5e9fa12e1..34aa303354bc 100644
--- a/include/linux/nfs4.h
+++ b/include/linux/nfs4.h
@@ -18,6 +18,7 @@
 #include <uapi/linux/nfs4.h>
 #include <linux/sunrpc/msg_prot.h>
 #include <linux/sunrpc/xdrgen/nfs4_1.h>
+#include <linux/sunrpc/xdrgen/nfs4_2.h>
 
 enum nfs4_acl_whotype {
 	NFS4_ACL_WHO_NAMED = 0,
diff --git a/include/linux/sunrpc/xdrgen/nfs4_2.h b/include/linux/sunrpc/xdrgen/nfs4_2.h
new file mode 100644
index 000000000000..9441f6cefbff
--- /dev/null
+++ b/include/linux/sunrpc/xdrgen/nfs4_2.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Generated by xdrgen. Manual edits will be lost. */
+/* XDR specification file: ../../Documentation/sunrpc/xdr/nfs4_2.x */
+/* XDR specification modification time: Fri Jun 12 10:44:36 2026 */
+
+#ifndef _LINUX_XDRGEN_NFS4_2_DEF_H
+#define _LINUX_XDRGEN_NFS4_2_DEF_H
+
+#include <linux/types.h>
+#include <linux/sunrpc/xdrgen/_defs.h>
+
+typedef bool fattr4_uncacheable_file_data;
+
+enum { FATTR4_UNCACHEABLE_FILE_DATA = 87 };
+
+#define NFS4_fattr4_uncacheable_file_data_sz \
+	(XDR_bool)
+
+#endif /* _LINUX_XDRGEN_NFS4_2_DEF_H */
-- 
2.47.3