[PATCH] RPC,NFS: new rpc_pipefs patch

 Currently rpc_mkdir/rpc_rmdir and rpc_mkpipe/mk_unlink have an API that's
 a little unfortunate.  They take a path relative to the rpc_pipefs root and
 thus need to perform a full lookup.  If you look at debugfs or usbfs they
 always store the dentry for directories they created and thus can pass in
 a dentry + single pathname component pair into their equivalents of the
 above functions.

 And in fact rpc_pipefs actually stores a dentry for all but one component so
 this change not only simplifies the core rpc_pipe code but also the callers.

 Unfortuntately this code path is only used by the NFS4 idmapper and
 AUTH_GSSAPI for which I don't have a test enviroment.  Could someone give
 it a spin?  It's the last bit needed before we can rework the
 lookup_hash API

 Signed-off-by: Christoph Hellwig <hch@lst.de>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 36 insertions, 17 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 5a8f01d726e9..63bf591310e0 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -67,26 +67,42 @@ static u32 *	call_verify(struct rpc_task *task);
 static int
 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
 {
-        static uint32_t clntid;
+        static unsigned int clntid;
+        char name[128];
         int error;
 
         if (dir_name == NULL)
                 return 0;
-        for (;;) {
-                snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
-                                "%s/clnt%x", dir_name,
-                                (unsigned int)clntid++);
-                clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
-                clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
-                if (!IS_ERR(clnt->cl_dentry))
-                        return 0;
+
+ retry_parent:
+        clnt->__cl_parent_dentry = rpc_mkdir(NULL, dir_name, NULL);
+        if (IS_ERR(clnt->__cl_parent_dentry)) {
+                error = PTR_ERR(clnt->__cl_parent_dentry);
+                if (error == -EEXIST)
+                        goto retry_parent; /* XXX(hch): WTF? */
+        
+                printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
+                                dir_name, error);
+                return error;
+        }
+
+
+ retry_child:
+        snprintf(name, sizeof(name), "clnt%x", clntid++);
+        name[sizeof(name) - 1] = '\0';
+
+        clnt->cl_dentry = rpc_mkdir(clnt->__cl_parent_dentry, name, clnt);
+        if (IS_ERR(clnt->cl_dentry)) {
                 error = PTR_ERR(clnt->cl_dentry);
-                if (error != -EEXIST) {
-                        printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
-                                        clnt->cl_pathname, error);
-                        return error;
-                }
+                if (error == -EEXIST)
+                        goto retry_child;
+                printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
+                                name, error);
+                rpc_rmdir(clnt->__cl_parent_dentry);
+                return error;
         }
+
+        return 0;
 }
 
 /*
@@ -174,7 +190,8 @@ rpc_new_client(struct rpc_xprt *xprt, char *servname,
         return clnt;
 
 out_no_auth:
-        rpc_rmdir(clnt->cl_pathname);
+        rpc_rmdir(clnt->cl_dentry);
+        rpc_rmdir(clnt->__cl_parent_dentry);
 out_no_path:
         if (clnt->cl_server != clnt->cl_inline_name)
                 kfree(clnt->cl_server);
@@ -302,8 +319,10 @@ rpc_destroy_client(struct rpc_clnt *clnt)
                 rpc_destroy_client(clnt->cl_parent);
                 goto out_free;
         }
-        if (clnt->cl_pathname[0])
-                rpc_rmdir(clnt->cl_pathname);
+        if (clnt->cl_dentry)
+                rpc_rmdir(clnt->cl_dentry);
+        if (clnt->__cl_parent_dentry)
+                rpc_rmdir(clnt->__cl_parent_dentry);
         if (clnt->cl_xprt) {
                 xprt_destroy(clnt->cl_xprt);
                 clnt->cl_xprt = NULL;