nfsd: only register cld pipe notifier when CONFIG_NFSD_V4 is enabled

Otherwise, we get a warning or error similar to this when building with
CONFIG_NFSD_V4 disabled:

    ERROR: "nfsd4_cld_block" [fs/nfsd/nfsd.ko] undefined!

Fix this by wrapping the calls to rpc_pipefs_notifier_register and
..._unregister in another function and providing no-op replacements
when CONFIG_NFSD_V4 is disabled.

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
index 1d1e8589b4ce..1671429ffa66 100644
--- a/fs/nfsd/nfsd.h
+++ b/fs/nfsd/nfsd.h
@@ -364,12 +364,17 @@ static inline u32 nfsd_suppattrs2(u32 minorversion)
         NFSD_WRITEABLE_ATTRS_WORD2
 
 extern int nfsd4_is_junction(struct dentry *dentry);
-#else
+extern int register_cld_notifier(void);
+extern void unregister_cld_notifier(void);
+#else /* CONFIG_NFSD_V4 */
 static inline int nfsd4_is_junction(struct dentry *dentry)
 {
         return 0;
 }
 
+#define register_cld_notifier() 0
+#define unregister_cld_notifier() do { } while(0)
+
 #endif /* CONFIG_NFSD_V4 */
 
 #endif /* LINUX_NFSD_NFSD_H */