From: Chuck Lever <chuck.lever@oracle.com>
Date: Sat, 8 Mar 2025 20:14:37 +0000 (-0500)
Subject: NFSD: Add /sys/kernel/debug/nfsd
X-Git-Tag: v6.16-rc1~138^2~50
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9fe5ea760e64f04412dbed51645a0dac7220d40a;p=thirdparty%2Fkernel%2Flinux.git

NFSD: Add /sys/kernel/debug/nfsd

Create a small sandbox under /sys/kernel/debug for experimental NFS
server feature settings. There is no API/ABI compatibility guarantee
for these settings.

The only documentation for such settings, if any documentation exists,
is in the kernel source code.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---

diff --git a/fs/nfsd/Makefile b/fs/nfsd/Makefile
index 2f687619f65b3..55744bb786c9a 100644
--- a/fs/nfsd/Makefile
+++ b/fs/nfsd/Makefile
@@ -24,6 +24,7 @@ nfsd-$(CONFIG_NFSD_BLOCKLAYOUT) += blocklayout.o blocklayoutxdr.o
 nfsd-$(CONFIG_NFSD_SCSILAYOUT) += blocklayout.o blocklayoutxdr.o
 nfsd-$(CONFIG_NFSD_FLEXFILELAYOUT) += flexfilelayout.o flexfilelayoutxdr.o
 nfsd-$(CONFIG_NFS_LOCALIO) += localio.o
+nfsd-$(CONFIG_DEBUG_FS) += debugfs.o
 
 
 .PHONY: xdrgen
diff --git a/fs/nfsd/debugfs.c b/fs/nfsd/debugfs.c
new file mode 100644
index 0000000000000..e913268d9c2da
--- /dev/null
+++ b/fs/nfsd/debugfs.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/debugfs.h>
+
+#include "nfsd.h"
+
+static struct dentry *nfsd_top_dir __read_mostly;
+
+void nfsd_debugfs_exit(void)
+{
+	debugfs_remove_recursive(nfsd_top_dir);
+	nfsd_top_dir = NULL;
+}
+
+void nfsd_debugfs_init(void)
+{
+	nfsd_top_dir = debugfs_create_dir("nfsd", NULL);
+}
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index f9763ced743d2..3f3e9f6c42501 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -2281,6 +2281,8 @@ static int __init init_nfsd(void)
 {
 	int retval;
 
+	nfsd_debugfs_init();
+
 	retval = nfsd4_init_slabs();
 	if (retval)
 		return retval;
@@ -2329,6 +2331,7 @@ out_free_pnfs:
 	nfsd4_exit_pnfs();
 out_free_slabs:
 	nfsd4_free_slabs();
+	nfsd_debugfs_exit();
 	return retval;
 }
 
@@ -2345,6 +2348,7 @@ static void __exit exit_nfsd(void)
 	nfsd_lockd_shutdown();
 	nfsd4_free_slabs();
 	nfsd4_exit_pnfs();
+	nfsd_debugfs_exit();
 }
 
 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index e2997f0ffbc53..8a53ddab5df01 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -156,6 +156,14 @@ void nfsd_reset_versions(struct nfsd_net *nn);
 int nfsd_create_serv(struct net *net);
 void nfsd_destroy_serv(struct net *net);
 
+#ifdef CONFIG_DEBUG_FS
+void nfsd_debugfs_init(void);
+void nfsd_debugfs_exit(void);
+#else
+static inline void nfsd_debugfs_init(void) {}
+static inline void nfsd_debugfs_exit(void) {}
+#endif
+
 extern int nfsd_max_blksize;
 
 static inline int nfsd_v4client(struct svc_rqst *rq)