3 files changed, 43 insertions, 3 deletions

diff --git a/fs/nfs/cache_lib.c b/fs/nfs/cache_lib.c
index 5dd017bbb7a2..5905a31211e5 100644
--- a/fs/nfs/cache_lib.c
+++ b/fs/nfs/cache_lib.c
@@ -112,7 +112,7 @@ int nfs_cache_wait_for_upcall(struct nfs_cache_defer_req *dreq)
         return 0;
 }
 
-static int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
+int nfs_cache_register_sb(struct super_block *sb, struct cache_detail *cd)
 {
         int ret;
         struct dentry *dir;
@@ -147,7 +147,7 @@ err:
         return ret;
 }
 
-static void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
+void nfs_cache_unregister_sb(struct super_block *sb, struct cache_detail *cd)
 {
         if (cd->u.pipefs.dir)
                 sunrpc_cache_unregister_pipefs(cd);
diff --git a/fs/nfs/cache_lib.h b/fs/nfs/cache_lib.h
index e0a6cc4b01b9..317db95e37f8 100644
--- a/fs/nfs/cache_lib.h
+++ b/fs/nfs/cache_lib.h
@@ -27,3 +27,7 @@ extern void nfs_cache_init(struct cache_detail *cd);
 extern void nfs_cache_destroy(struct cache_detail *cd);
 extern int nfs_cache_register_net(struct net *net, struct cache_detail *cd);
 extern void nfs_cache_unregister_net(struct net *net, struct cache_detail *cd);
+extern int nfs_cache_register_sb(struct super_block *sb,
+                                 struct cache_detail *cd);
+extern void nfs_cache_unregister_sb(struct super_block *sb,
+                                    struct cache_detail *cd);
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index 9aea78ab86ac..200eb67c95d9 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -40,6 +40,7 @@ ssize_t nfs_dns_resolve_name(struct net *net, char *name, size_t namelen,
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/cache.h>
 #include <linux/sunrpc/svcauth.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
 
 #include "dns_resolve.h"
 #include "cache_lib.h"
@@ -400,12 +401,47 @@ void nfs_dns_resolver_cache_destroy(struct net *net)
         kfree(cd);
 }
 
+static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
+                           void *ptr)
+{
+        struct super_block *sb = ptr;
+        struct net *net = sb->s_fs_info;
+        struct nfs_net *nn = net_generic(net, nfs_net_id);
+        struct cache_detail *cd = nn->nfs_dns_resolve;
+        int ret = 0;
+
+        if (cd == NULL)
+                return 0;
+
+        if (!try_module_get(THIS_MODULE))
+                return 0;
+
+        switch (event) {
+        case RPC_PIPEFS_MOUNT:
+                ret = nfs_cache_register_sb(sb, cd);
+                break;
+        case RPC_PIPEFS_UMOUNT:
+                nfs_cache_unregister_sb(sb, cd);
+                break;
+        default:
+                ret = -ENOTSUPP;
+                break;
+        }
+        module_put(THIS_MODULE);
+        return ret;
+}
+
+static struct notifier_block nfs_dns_resolver_block = {
+        .notifier_call  = rpc_pipefs_event,
+};
+
 int nfs_dns_resolver_init(void)
 {
-        return 0;
+        return rpc_pipefs_notifier_register(&nfs_dns_resolver_block);
 }
 
 void nfs_dns_resolver_destroy(void)
 {
+        rpc_pipefs_notifier_unregister(&nfs_dns_resolver_block);
 }
 #endif