SUNRPC: hold current network namespace while pipefs superblock is active

We want to be sure that network namespace is still alive while we have pipefs
mounted.
This will be required later, when RPC pipefs will be mounting only from
user-space context.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index e32e6b8c006..f628b0f48a8 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -27,6 +27,9 @@
 #include <linux/workqueue.h>
 #include <linux/sunrpc/rpc_pipe_fs.h>
 #include <linux/sunrpc/cache.h>
+#include <linux/nsproxy.h>
+
+#include "netns.h"
 
 static struct vfsmount *rpc_mnt __read_mostly;
 static int rpc_mount_count;
@@ -1011,6 +1014,7 @@ rpc_fill_super(struct super_block *sb, void *data, int silent)
         }
         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
                 return -ENOMEM;
+        sb->s_fs_info = get_net(net);
         return 0;
 }
 
@@ -1021,11 +1025,19 @@ rpc_mount(struct file_system_type *fs_type,
         return mount_ns(fs_type, flags, current->nsproxy->net_ns, rpc_fill_super);
 }
 
+void rpc_kill_sb(struct super_block *sb)
+{
+        struct net *net = sb->s_fs_info;
+
+        put_net(net);
+        kill_litter_super(sb);
+}
+
 static struct file_system_type rpc_pipe_fs_type = {
         .owner          = THIS_MODULE,
         .name           = "rpc_pipefs",
         .mount          = rpc_mount,
-        .kill_sb        = kill_litter_super,
+        .kill_sb        = rpc_kill_sb,
 };
 
 static void