[PATCH 5/6] NFS: handle NFS idmap pipe PipeFS dentries by network namespace aware routines

[Stanislav Kinsbursky <skinsbursky@parallels.com>]

This patch makes NFS idmap pipes dentries allocated and destroyed in network
namespace context by PipeFS network namespace aware routines.
Network namespace context is obtained from nfs_client structure.

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

---
 fs/nfs/idmap.c |   61 +++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 60698a1..0680f63 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -350,6 +350,56 @@ static const struct rpc_pipe_ops idmap_upcall_ops = {
 	.destroy_msg	= idmap_pipe_destroy_msg,
 };
 
+static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
+{
+	if (pipe->dentry)
+		rpc_unlink(pipe->dentry);
+}
+
+static int __nfs_idmap_register(struct dentry *dir,
+				     struct idmap *idmap,
+				     struct rpc_pipe *pipe)
+{
+	struct dentry *dentry;
+
+	dentry = rpc_mkpipe_dentry(dir, "idmap", idmap, pipe);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	pipe->dentry = dentry;
+	return 0;
+}
+
+static void nfs_idmap_unregister(struct nfs_client *clp,
+				      struct rpc_pipe *pipe)
+{
+	struct net *net = clp->net;
+	struct super_block *pipefs_sb;
+
+	pipefs_sb = rpc_get_sb_net(net);
+	if (pipefs_sb) {
+		__nfs_idmap_unregister(pipe);
+		rpc_put_sb_net(net);
+	}
+}
+
+static int nfs_idmap_register(struct nfs_client *clp,
+				   struct idmap *idmap,
+				   struct rpc_pipe *pipe)
+{
+	struct net *net = clp->net;
+	struct super_block *pipefs_sb;
+	int err = 0;
+
+	pipefs_sb = rpc_get_sb_net(net);
+	if (pipefs_sb) {
+		if (clp->cl_rpcclient->cl_dentry)
+			err = __nfs_idmap_register(clp->cl_rpcclient->cl_dentry,
+						   idmap, pipe);
+		rpc_put_sb_net(net);
+	}
+	return err;
+}
+
 int
 nfs_idmap_new(struct nfs_client *clp)
 {
@@ -369,12 +419,8 @@ nfs_idmap_new(struct nfs_client *clp)
 		kfree(idmap);
 		return error;
 	}
-
-	if (clp->cl_rpcclient->cl_dentry)
-		pipe->dentry = rpc_mkpipe_dentry(clp->cl_rpcclient->cl_dentry,
-				"idmap", idmap, pipe);
-	if (IS_ERR(pipe->dentry)) {
-		error = PTR_ERR(pipe->dentry);
+	error = nfs_idmap_register(clp, idmap, pipe);
+	if (error) {
 		rpc_destroy_pipe_data(pipe);
 		kfree(idmap);
 		return error;
@@ -397,8 +443,7 @@ nfs_idmap_delete(struct nfs_client *clp)
 
 	if (!idmap)
 		return;
-	if (idmap->idmap_pipe->dentry)
-		rpc_unlink(idmap->idmap_pipe->dentry);
+	nfs_idmap_unregister(clp, idmap->idmap_pipe);
 	rpc_destroy_pipe_data(idmap->idmap_pipe);
 	clp->cl_idmap = NULL;
 	kfree(idmap);