NFSv4.2: Fix NFS4ERR_STALE error when doing inter server copy

NFS_FS=y as dependency of CONFIG_NFSD_V4_2_INTER_SSC still have
build errors and some configs with NFSD=m to get NFS4ERR_STALE
error when doing inter server copy.

Added ops table in nfs_common for knfsd to access NFS client modules.

Fixes: 3ac3711adb88 ("NFSD: Fix NFS server build errors")
Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

3 files changed, 54 insertions, 6 deletions

diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index fdfc77486ace..984938024011 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -9,6 +9,7 @@
 #include <linux/falloc.h>
 #include <linux/mount.h>
 #include <linux/nfs_fs.h>
+#include <linux/nfs_ssc.h>
 #include "delegation.h"
 #include "internal.h"
 #include "iostat.h"
@@ -314,9 +315,8 @@ out:
 static int read_name_gen = 1;
 #define SSC_READ_NAME_BODY "ssc_read_%d"
 
-struct file *
-nfs42_ssc_open(struct vfsmount *ss_mnt, struct nfs_fh *src_fh,
-		nfs4_stateid *stateid)
+static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
+		struct nfs_fh *src_fh, nfs4_stateid *stateid)
 {
 	struct nfs_fattr fattr;
 	struct file *filep, *res;
@@ -398,14 +398,40 @@ out_filep:
 	fput(filep);
 	goto out_free_name;
 }
-EXPORT_SYMBOL_GPL(nfs42_ssc_open);
-void nfs42_ssc_close(struct file *filep)
+
+static void __nfs42_ssc_close(struct file *filep)
 {
 	struct nfs_open_context *ctx = nfs_file_open_context(filep);
 
 	ctx->state->flags = 0;
 }
-EXPORT_SYMBOL_GPL(nfs42_ssc_close);
+
+static const struct nfs4_ssc_client_ops nfs4_ssc_clnt_ops_tbl = {
+	.sco_open = __nfs42_ssc_open,
+	.sco_close = __nfs42_ssc_close,
+};
+
+/**
+ * nfs42_ssc_register_ops - Wrapper to register NFS_V4 ops in nfs_common
+ *
+ * Return values:
+ *   None
+ */
+void nfs42_ssc_register_ops(void)
+{
+	nfs42_ssc_register(&nfs4_ssc_clnt_ops_tbl);
+}
+
+/**
+ * nfs42_ssc_unregister_ops - wrapper to un-register NFS_V4 ops in nfs_common
+ *
+ * Return values:
+ *   None.
+ */
+void nfs42_ssc_unregister_ops(void)
+{
+	nfs42_ssc_unregister(&nfs4_ssc_clnt_ops_tbl);
+}
 #endif /* CONFIG_NFS_V4_2 */
 
 const struct file_operations nfs4_file_operations = {
diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c
index 0c1ab846b83d..93f5c1678ec2 100644
--- a/fs/nfs/nfs4super.c
+++ b/fs/nfs/nfs4super.c
@@ -7,6 +7,7 @@
 #include <linux/mount.h>
 #include <linux/nfs4_mount.h>
 #include <linux/nfs_fs.h>
+#include <linux/nfs_ssc.h>
 #include "delegation.h"
 #include "internal.h"
 #include "nfs4_fs.h"
@@ -279,6 +280,9 @@ static int __init init_nfs_v4(void)
 	if (err)
 		goto out2;
 
+#ifdef CONFIG_NFS_V4_2
+	nfs42_ssc_register_ops();
+#endif
 	register_nfs_version(&nfs_v4);
 	return 0;
 out2:
@@ -297,6 +301,7 @@ static void __exit exit_nfs_v4(void)
 	unregister_nfs_version(&nfs_v4);
 #ifdef CONFIG_NFS_V4_2
 	nfs4_xattr_cache_exit();
+	nfs42_ssc_unregister_ops();
 #endif
 	nfs4_unregister_sysctl();
 	nfs_idmap_quit();
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 7a70287f21a2..f7dad8227a5f 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -57,6 +57,7 @@
 #include <linux/rcupdate.h>
 
 #include <linux/uaccess.h>
+#include <linux/nfs_ssc.h>
 
 #include "nfs4_fs.h"
 #include "callback.h"
@@ -85,6 +86,10 @@ const struct super_operations nfs_sops = {
 };
 EXPORT_SYMBOL_GPL(nfs_sops);
 
+static const struct nfs_ssc_client_ops nfs_ssc_clnt_ops_tbl = {
+	.sco_sb_deactive = nfs_sb_deactive,
+};
+
 #if IS_ENABLED(CONFIG_NFS_V4)
 static int __init register_nfs4_fs(void)
 {
@@ -106,6 +111,16 @@ static void unregister_nfs4_fs(void)
 }
 #endif
 
+static void nfs_ssc_register_ops(void)
+{
+	nfs_ssc_register(&nfs_ssc_clnt_ops_tbl);
+}
+
+static void nfs_ssc_unregister_ops(void)
+{
+	nfs_ssc_unregister(&nfs_ssc_clnt_ops_tbl);
+}
+
 static struct shrinker acl_shrinker = {
 	.count_objects	= nfs_access_cache_count,
 	.scan_objects	= nfs_access_cache_scan,
@@ -133,6 +148,7 @@ int __init register_nfs_fs(void)
 	ret = register_shrinker(&acl_shrinker);
 	if (ret < 0)
 		goto error_3;
+	nfs_ssc_register_ops();
 	return 0;
 error_3:
 	nfs_unregister_sysctl();
@@ -152,6 +168,7 @@ void __exit unregister_nfs_fs(void)
 	unregister_shrinker(&acl_shrinker);
 	nfs_unregister_sysctl();
 	unregister_nfs4_fs();
+	nfs_ssc_unregister_ops();
 	unregister_filesystem(&nfs_fs_type);
 }