[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>

3 files changed, 133 insertions, 197 deletions

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index d2b08f16c257..bd2555139fa9 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -87,7 +87,6 @@ struct gss_auth {
         struct list_head upcalls;
         struct rpc_clnt *client;
         struct dentry *dentry;
-        char path[48];
         spinlock_t lock;
 };
 
@@ -690,10 +689,8 @@ gss_create(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
         if (err)
                 goto err_put_mech;
 
-        snprintf(gss_auth->path, sizeof(gss_auth->path), "%s/%s",
-                        clnt->cl_pathname,
-                        gss_auth->mech->gm_name);
-        gss_auth->dentry = rpc_mkpipe(gss_auth->path, clnt, &gss_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
+        gss_auth->dentry = rpc_mkpipe(clnt->cl_dentry, gss_auth->mech->gm_name,
+                        clnt, &gss_upcall_ops, RPC_PIPE_WAIT_FOR_OPEN);
         if (IS_ERR(gss_auth->dentry)) {
                 err = PTR_ERR(gss_auth->dentry);
                 goto err_put_mech;
@@ -718,7 +715,7 @@ gss_destroy(struct rpc_auth *auth)
                 auth, auth->au_flavor);
 
         gss_auth = container_of(auth, struct gss_auth, rpc_auth);
-        rpc_unlink(gss_auth->path);
+        rpc_unlink(gss_auth->dentry);
         gss_mech_put(gss_auth->mech);
 
         rpcauth_free_credcache(auth);
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;
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index ded6c63f11ec..b382809726d8 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -414,38 +414,6 @@ rpc_put_mount(void)
         simple_release_fs(&rpc_mount, &rpc_mount_count);
 }
 
-static int
-rpc_lookup_parent(char *path, struct nameidata *nd)
-{
-        if (path[0] == '\0')
-                return -ENOENT;
-        if (rpc_get_mount()) {
-                printk(KERN_WARNING "%s: %s failed to mount "
-                               "pseudofilesystem \n", __FILE__, __FUNCTION__);
-                return -ENODEV;
-        }
-        nd->mnt = mntget(rpc_mount);
-        nd->dentry = dget(rpc_mount->mnt_root);
-        nd->last_type = LAST_ROOT;
-        nd->flags = LOOKUP_PARENT;
-        nd->depth = 0;
-
-        if (path_walk(path, nd)) {
-                printk(KERN_WARNING "%s: %s failed to find path %s\n",
-                                __FILE__, __FUNCTION__, path);
-                rpc_put_mount();
-                return -ENOENT;
-        }
-        return 0;
-}
-
-static void
-rpc_release_path(struct nameidata *nd)
-{
-        path_release(nd);
-        rpc_put_mount();
-}
-
 static struct inode *
 rpc_get_inode(struct super_block *sb, int mode)
 {
@@ -550,197 +518,149 @@ out_bad:
         return -ENOMEM;
 }
 
-static int
-__rpc_mkdir(struct inode *dir, struct dentry *dentry)
+struct dentry *
+rpc_mkdir(struct dentry *parent, char *name, struct rpc_clnt *rpc_client)
 {
+        struct inode *dir;
+        struct dentry *dentry;
         struct inode *inode;
-
-        inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
-        if (!inode)
-                goto out_err;
-        inode->i_ino = iunique(dir->i_sb, 100);
-        d_instantiate(dentry, inode);
-        dir->i_nlink++;
-        inode_dir_notify(dir, DN_CREATE);
-        rpc_get_mount();
-        return 0;
-out_err:
-        printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
-                        __FILE__, __FUNCTION__, dentry->d_name.name);
-        return -ENOMEM;
-}
-
-static int
-__rpc_rmdir(struct inode *dir, struct dentry *dentry)
-{
         int error;
 
-        shrink_dcache_parent(dentry);
-        if (dentry->d_inode) {
-                rpc_close_pipes(dentry->d_inode);
-                rpc_inode_setowner(dentry->d_inode, NULL);
-        }
-        if ((error = simple_rmdir(dir, dentry)) != 0)
-                return error;
-        if (!error) {
-                inode_dir_notify(dir, DN_DELETE);
-                d_drop(dentry);
-                rpc_put_mount();
-        }
-        return 0;
-}
+        if (!parent)
+                parent = rpc_mount->mnt_root;
 
-static struct dentry *
-rpc_lookup_negative(char *path, struct nameidata *nd)
-{
-        struct dentry *dentry;
-        struct inode *dir;
-        int error;
-
-        if ((error = rpc_lookup_parent(path, nd)) != 0)
+        dir = parent->d_inode;
+        
+        error = rpc_get_mount();
+        if (error)
                 return ERR_PTR(error);
-        dir = nd->dentry->d_inode;
+
         down(&dir->i_sem);
-        dentry = lookup_hash(&nd->last, nd->dentry);
+        dentry = lookup_one_len(name, parent, strlen(name));
         if (IS_ERR(dentry))
-                goto out_err;
+                goto out_unlock;
         if (dentry->d_inode) {
-                dput(dentry);
                 dentry = ERR_PTR(-EEXIST);
-                goto out_err;
+                goto out_dput;
         }
-        return dentry;
-out_err:
-        up(&dir->i_sem);
-        rpc_release_path(nd);
-        return dentry;
-}
 
+        inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
+        if (!inode)
+                goto out_dput;
+        inode->i_ino = iunique(dir->i_sb, 100);
+        dir->i_nlink++;
+        RPC_I(dentry->d_inode)->private = rpc_client;
 
-struct dentry *
-rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
-{
-        struct nameidata nd;
-        struct dentry *dentry;
-        struct inode *dir;
-        int error;
+        d_instantiate(dentry, inode);
+        dget(dentry);
+        up(&dir->i_sem);
+
+        inode_dir_notify(dir, DN_CREATE);
 
-        dentry = rpc_lookup_negative(path, &nd);
-        if (IS_ERR(dentry))
-                return dentry;
-        dir = nd.dentry->d_inode;
-        if ((error = __rpc_mkdir(dir, dentry)) != 0)
-                goto err_dput;
-        RPC_I(dentry->d_inode)->private = rpc_client;
         error = rpc_populate(dentry, authfiles,
                         RPCAUTH_info, RPCAUTH_EOF);
         if (error)
-                goto err_depopulate;
-out:
-        up(&dir->i_sem);
-        rpc_release_path(&nd);
+                goto out_depopulate;
+
         return dentry;
-err_depopulate:
-        rpc_depopulate(dentry);
-        __rpc_rmdir(dir, dentry);
-err_dput:
+
+ out_depopulate:
+        rpc_rmdir(dentry);
+ out_dput:
         dput(dentry);
-        printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
-                        __FILE__, __FUNCTION__, path, error);
-        dentry = ERR_PTR(error);
-        goto out;
+ out_unlock:
+        up(&dir->i_sem);
+        rpc_put_mount();
+        return dentry;
 }
 
-int
-rpc_rmdir(char *path)
+void
+rpc_rmdir(struct dentry *dentry)
 {
-        struct nameidata nd;
-        struct dentry *dentry;
-        struct inode *dir;
-        int error;
+        struct dentry *parent = dentry->d_parent;
 
-        if ((error = rpc_lookup_parent(path, &nd)) != 0)
-                return error;
-        dir = nd.dentry->d_inode;
-        down(&dir->i_sem);
-        dentry = lookup_hash(&nd.last, nd.dentry);
-        if (IS_ERR(dentry)) {
-                error = PTR_ERR(dentry);
-                goto out_release;
-        }
         rpc_depopulate(dentry);
-        error = __rpc_rmdir(dir, dentry);
-        dput(dentry);
-out_release:
-        up(&dir->i_sem);
-        rpc_release_path(&nd);
-        return error;
+
+        down(&parent->d_inode->i_sem);
+        if (dentry->d_inode) {
+                rpc_close_pipes(dentry->d_inode);
+                rpc_inode_setowner(dentry->d_inode, NULL);
+                simple_rmdir(parent->d_inode, dentry);
+        }
+        up(&parent->d_inode->i_sem);
+
+        inode_dir_notify(parent->d_inode, DN_DELETE);
+        rpc_put_mount();
 }
 
 struct dentry *
-rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
+rpc_mkpipe(struct dentry *parent, char *name, void *private,
+           struct rpc_pipe_ops *ops, int flags)
 {
-        struct nameidata nd;
+        struct inode *dir = parent->d_inode;
         struct dentry *dentry;
-        struct inode *dir, *inode;
+        struct inode *inode;
         struct rpc_inode *rpci;
+        int error;
+
+        error = rpc_get_mount();
+        if (error)
+                return ERR_PTR(error);
 
-        dentry = rpc_lookup_negative(path, &nd);
+        down(&parent->d_inode->i_sem);
+        dentry = lookup_one_len(name, parent, strlen(name));
         if (IS_ERR(dentry))
-                return dentry;
-        dir = nd.dentry->d_inode;
-        inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
-        if (!inode)
-                goto err_dput;
+                goto out_unlock;
+        if (dentry->d_inode) {
+                dentry = ERR_PTR(-EEXIST);
+                goto out_dput;
+        }
+
+        inode = rpc_get_inode(parent->d_inode->i_sb,
+                        S_IFSOCK | S_IRUSR | S_IWUSR);
+        if (!inode) {
+                dentry = ERR_PTR(-ENOMEM);
+                goto out_dput;
+        }
+
         inode->i_ino = iunique(dir->i_sb, 100);
         inode->i_fop = &rpc_pipe_fops;
-        d_instantiate(dentry, inode);
+
         rpci = RPC_I(inode);
         rpci->private = private;
         rpci->flags = flags;
         rpci->ops = ops;
+
+        d_instantiate(dentry, inode);
+        dget(dentry);
+        up(&parent->d_inode->i_sem);
+
         inode_dir_notify(dir, DN_CREATE);
-out:
-        up(&dir->i_sem);
-        rpc_release_path(&nd);
         return dentry;
-err_dput:
+
+ out_dput:
         dput(dentry);
-        dentry = ERR_PTR(-ENOMEM);
-        printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
-                        __FILE__, __FUNCTION__, path, -ENOMEM);
-        goto out;
+ out_unlock:
+        up(&parent->d_inode->i_sem);
+        rpc_put_mount();
+        return dentry;
 }
 
-int
-rpc_unlink(char *path)
+void
+rpc_unlink(struct dentry *dentry)
 {
-        struct nameidata nd;
-        struct dentry *dentry;
-        struct inode *dir;
-        int error;
+        struct dentry *parent = dentry->d_parent;
 
-        if ((error = rpc_lookup_parent(path, &nd)) != 0)
-                return error;
-        dir = nd.dentry->d_inode;
-        down(&dir->i_sem);
-        dentry = lookup_hash(&nd.last, nd.dentry);
-        if (IS_ERR(dentry)) {
-                error = PTR_ERR(dentry);
-                goto out_release;
-        }
-        d_drop(dentry);
+        down(&parent->d_inode->i_sem);
         if (dentry->d_inode) {
                 rpc_close_pipes(dentry->d_inode);
                 rpc_inode_setowner(dentry->d_inode, NULL);
-                error = simple_unlink(dir, dentry);
+                simple_unlink(parent->d_inode, dentry);
         }
-        dput(dentry);
-        inode_dir_notify(dir, DN_DELETE);
-out_release:
-        up(&dir->i_sem);
-        rpc_release_path(&nd);
-        return error;
+        up(&parent->d_inode->i_sem);
+
+        inode_dir_notify(parent->d_inode, DN_DELETE);
+        rpc_put_mount();
 }
 
 /*