1 files changed, 838 insertions, 0 deletions

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
new file mode 100644
index 00000000000..554f224c044
--- /dev/null
+++ b/net/sunrpc/rpc_pipe.c
@@ -0,0 +1,838 @@
+/*
+ * net/sunrpc/rpc_pipe.c
+ *
+ * Userland/kernel interface for rpcauth_gss.
+ * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
+ * and fs/driverfs/inode.c
+ *
+ * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
+ *
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/dnotify.h>
+#include <linux/kernel.h>
+
+#include <asm/ioctls.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/wait.h>
+#include <linux/seq_file.h>
+
+#include <linux/sunrpc/clnt.h>
+#include <linux/workqueue.h>
+#include <linux/sunrpc/rpc_pipe_fs.h>
+
+static struct vfsmount *rpc_mount;
+static int rpc_mount_count;
+
+static struct file_system_type rpc_pipe_fs_type;
+
+
+static kmem_cache_t *rpc_inode_cachep;
+
+#define RPC_UPCALL_TIMEOUT (30*HZ)
+
+static void
+__rpc_purge_upcall(struct inode *inode, int err)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	struct rpc_pipe_msg *msg;
+
+	while (!list_empty(&rpci->pipe)) {
+		msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
+		list_del_init(&msg->list);
+		msg->errno = err;
+		rpci->ops->destroy_msg(msg);
+	}
+	while (!list_empty(&rpci->in_upcall)) {
+		msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
+		list_del_init(&msg->list);
+		msg->errno = err;
+		rpci->ops->destroy_msg(msg);
+	}
+	rpci->pipelen = 0;
+	wake_up(&rpci->waitq);
+}
+
+static void
+rpc_timeout_upcall_queue(void *data)
+{
+	struct rpc_inode *rpci = (struct rpc_inode *)data;
+	struct inode *inode = &rpci->vfs_inode;
+
+	down(&inode->i_sem);
+	if (rpci->nreaders == 0 && !list_empty(&rpci->pipe))
+		__rpc_purge_upcall(inode, -ETIMEDOUT);
+	up(&inode->i_sem);
+}
+
+int
+rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	int res = 0;
+
+	down(&inode->i_sem);
+	if (rpci->nreaders) {
+		list_add_tail(&msg->list, &rpci->pipe);
+		rpci->pipelen += msg->len;
+	} else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
+		if (list_empty(&rpci->pipe))
+			schedule_delayed_work(&rpci->queue_timeout,
+					RPC_UPCALL_TIMEOUT);
+		list_add_tail(&msg->list, &rpci->pipe);
+		rpci->pipelen += msg->len;
+	} else
+		res = -EPIPE;
+	up(&inode->i_sem);
+	wake_up(&rpci->waitq);
+	return res;
+}
+
+static void
+rpc_close_pipes(struct inode *inode)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+
+	cancel_delayed_work(&rpci->queue_timeout);
+	flush_scheduled_work();
+	down(&inode->i_sem);
+	if (rpci->ops != NULL) {
+		rpci->nreaders = 0;
+		__rpc_purge_upcall(inode, -EPIPE);
+		rpci->nwriters = 0;
+		if (rpci->ops->release_pipe)
+			rpci->ops->release_pipe(inode);
+		rpci->ops = NULL;
+	}
+	up(&inode->i_sem);
+}
+
+static inline void
+rpc_inode_setowner(struct inode *inode, void *private)
+{
+	RPC_I(inode)->private = private;
+}
+
+static struct inode *
+rpc_alloc_inode(struct super_block *sb)
+{
+	struct rpc_inode *rpci;
+	rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, SLAB_KERNEL);
+	if (!rpci)
+		return NULL;
+	return &rpci->vfs_inode;
+}
+
+static void
+rpc_destroy_inode(struct inode *inode)
+{
+	kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
+}
+
+static int
+rpc_pipe_open(struct inode *inode, struct file *filp)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	int res = -ENXIO;
+
+	down(&inode->i_sem);
+	if (rpci->ops != NULL) {
+		if (filp->f_mode & FMODE_READ)
+			rpci->nreaders ++;
+		if (filp->f_mode & FMODE_WRITE)
+			rpci->nwriters ++;
+		res = 0;
+	}
+	up(&inode->i_sem);
+	return res;
+}
+
+static int
+rpc_pipe_release(struct inode *inode, struct file *filp)
+{
+	struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
+	struct rpc_pipe_msg *msg;
+
+	down(&inode->i_sem);
+	if (rpci->ops == NULL)
+		goto out;
+	msg = (struct rpc_pipe_msg *)filp->private_data;
+	if (msg != NULL) {
+		msg->errno = -EPIPE;
+		list_del_init(&msg->list);
+		rpci->ops->destroy_msg(msg);
+	}
+	if (filp->f_mode & FMODE_WRITE)
+		rpci->nwriters --;
+	if (filp->f_mode & FMODE_READ)
+		rpci->nreaders --;
+	if (!rpci->nreaders)
+		__rpc_purge_upcall(inode, -EPIPE);
+	if (rpci->ops->release_pipe)
+		rpci->ops->release_pipe(inode);
+out:
+	up(&inode->i_sem);
+	return 0;
+}
+
+static ssize_t
+rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct rpc_inode *rpci = RPC_I(inode);
+	struct rpc_pipe_msg *msg;
+	int res = 0;
+
+	down(&inode->i_sem);
+	if (rpci->ops == NULL) {
+		res = -EPIPE;
+		goto out_unlock;
+	}
+	msg = filp->private_data;
+	if (msg == NULL) {
+		if (!list_empty(&rpci->pipe)) {
+			msg = list_entry(rpci->pipe.next,
+					struct rpc_pipe_msg,
+					list);
+			list_move(&msg->list, &rpci->in_upcall);
+			rpci->pipelen -= msg->len;
+			filp->private_data = msg;
+			msg->copied = 0;
+		}
+		if (msg == NULL)
+			goto out_unlock;
+	}
+	/* NOTE: it is up to the callback to update msg->copied */
+	res = rpci->ops->upcall(filp, msg, buf, len);
+	if (res < 0 || msg->len == msg->copied) {
+		filp->private_data = NULL;
+		list_del_init(&msg->list);
+		rpci->ops->destroy_msg(msg);
+	}
+out_unlock:
+	up(&inode->i_sem);
+	return res;
+}
+
+static ssize_t
+rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct rpc_inode *rpci = RPC_I(inode);
+	int res;
+
+	down(&inode->i_sem);
+	res = -EPIPE;
+	if (rpci->ops != NULL)
+		res = rpci->ops->downcall(filp, buf, len);
+	up(&inode->i_sem);
+	return res;
+}
+
+static unsigned int
+rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
+{
+	struct rpc_inode *rpci;
+	unsigned int mask = 0;
+
+	rpci = RPC_I(filp->f_dentry->d_inode);
+	poll_wait(filp, &rpci->waitq, wait);
+
+	mask = POLLOUT | POLLWRNORM;
+	if (rpci->ops == NULL)
+		mask |= POLLERR | POLLHUP;
+	if (!list_empty(&rpci->pipe))
+		mask |= POLLIN | POLLRDNORM;
+	return mask;
+}
+
+static int
+rpc_pipe_ioctl(struct inode *ino, struct file *filp,
+		unsigned int cmd, unsigned long arg)
+{
+	struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
+	int len;
+
+	switch (cmd) {
+	case FIONREAD:
+		if (rpci->ops == NULL)
+			return -EPIPE;
+		len = rpci->pipelen;
+		if (filp->private_data) {
+			struct rpc_pipe_msg *msg;
+			msg = (struct rpc_pipe_msg *)filp->private_data;
+			len += msg->len - msg->copied;
+		}
+		return put_user(len, (int __user *)arg);
+	default:
+		return -EINVAL;
+	}
+}
+
+static struct file_operations rpc_pipe_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.read		= rpc_pipe_read,
+	.write		= rpc_pipe_write,
+	.poll		= rpc_pipe_poll,
+	.ioctl		= rpc_pipe_ioctl,
+	.open		= rpc_pipe_open,
+	.release	= rpc_pipe_release,
+};
+
+static int
+rpc_show_info(struct seq_file *m, void *v)
+{
+	struct rpc_clnt *clnt = m->private;
+
+	seq_printf(m, "RPC server: %s\n", clnt->cl_server);
+	seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
+			clnt->cl_prog, clnt->cl_vers);
+	seq_printf(m, "address: %u.%u.%u.%u\n",
+			NIPQUAD(clnt->cl_xprt->addr.sin_addr.s_addr));
+	seq_printf(m, "protocol: %s\n",
+			clnt->cl_xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
+	return 0;
+}
+
+static int
+rpc_info_open(struct inode *inode, struct file *file)
+{
+	struct rpc_clnt *clnt;
+	int ret = single_open(file, rpc_show_info, NULL);
+
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+		down(&inode->i_sem);
+		clnt = RPC_I(inode)->private;
+		if (clnt) {
+			atomic_inc(&clnt->cl_users);
+			m->private = clnt;
+		} else {
+			single_release(inode, file);
+			ret = -EINVAL;
+		}
+		up(&inode->i_sem);
+	}
+	return ret;
+}
+
+static int
+rpc_info_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+	struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
+
+	if (clnt)
+		rpc_release_client(clnt);
+	return single_release(inode, file);
+}
+
+static struct file_operations rpc_info_operations = {
+	.owner		= THIS_MODULE,
+	.open		= rpc_info_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= rpc_info_release,
+};
+
+
+/*
+ * We have a single directory with 1 node in it.
+ */
+enum {
+	RPCAUTH_Root = 1,
+	RPCAUTH_lockd,
+	RPCAUTH_mount,
+	RPCAUTH_nfs,
+	RPCAUTH_portmap,
+	RPCAUTH_statd,
+	RPCAUTH_RootEOF
+};
+
+/*
+ * Description of fs contents.
+ */
+struct rpc_filelist {
+	char *name;
+	struct file_operations *i_fop;
+	int mode;
+};
+
+static struct rpc_filelist files[] = {
+	[RPCAUTH_lockd] = {
+		.name = "lockd",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+	[RPCAUTH_mount] = {
+		.name = "mount",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+	[RPCAUTH_nfs] = {
+		.name = "nfs",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+	[RPCAUTH_portmap] = {
+		.name = "portmap",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+	[RPCAUTH_statd] = {
+		.name = "statd",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+};
+
+enum {
+	RPCAUTH_info = 2,
+	RPCAUTH_EOF
+};
+
+static struct rpc_filelist authfiles[] = {
+	[RPCAUTH_info] = {
+		.name = "info",
+		.i_fop = &rpc_info_operations,
+		.mode = S_IFREG | S_IRUSR,
+	},
+};
+
+static int
+rpc_get_mount(void)
+{
+	return simple_pin_fs("rpc_pipefs", &rpc_mount, &rpc_mount_count);
+}
+
+static void
+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)
+{
+	struct inode *inode = new_inode(sb);
+	if (!inode)
+		return NULL;
+	inode->i_mode = mode;
+	inode->i_uid = inode->i_gid = 0;
+	inode->i_blksize = PAGE_CACHE_SIZE;
+	inode->i_blocks = 0;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	switch(mode & S_IFMT) {
+		case S_IFDIR:
+			inode->i_fop = &simple_dir_operations;
+			inode->i_op = &simple_dir_inode_operations;
+			inode->i_nlink++;
+		default:
+			break;
+	}
+	return inode;
+}
+
+/*
+ * FIXME: This probably has races.
+ */
+static void
+rpc_depopulate(struct dentry *parent)
+{
+	struct inode *dir = parent->d_inode;
+	struct list_head *pos, *next;
+	struct dentry *dentry, *dvec[10];
+	int n = 0;
+
+	down(&dir->i_sem);
+repeat:
+	spin_lock(&dcache_lock);
+	list_for_each_safe(pos, next, &parent->d_subdirs) {
+		dentry = list_entry(pos, struct dentry, d_child);
+		spin_lock(&dentry->d_lock);
+		if (!d_unhashed(dentry)) {
+			dget_locked(dentry);
+			__d_drop(dentry);
+			spin_unlock(&dentry->d_lock);
+			dvec[n++] = dentry;
+			if (n == ARRAY_SIZE(dvec))
+				break;
+		} else
+			spin_unlock(&dentry->d_lock);
+	}
+	spin_unlock(&dcache_lock);
+	if (n) {
+		do {
+			dentry = dvec[--n];
+			if (dentry->d_inode) {
+				rpc_close_pipes(dentry->d_inode);
+				rpc_inode_setowner(dentry->d_inode, NULL);
+				simple_unlink(dir, dentry);
+			}
+			dput(dentry);
+		} while (n);
+		goto repeat;
+	}
+	up(&dir->i_sem);
+}
+
+static int
+rpc_populate(struct dentry *parent,
+		struct rpc_filelist *files,
+		int start, int eof)
+{
+	struct inode *inode, *dir = parent->d_inode;
+	void *private = RPC_I(dir)->private;
+	struct dentry *dentry;
+	int mode, i;
+
+	down(&dir->i_sem);
+	for (i = start; i < eof; i++) {
+		dentry = d_alloc_name(parent, files[i].name);
+		if (!dentry)
+			goto out_bad;
+		mode = files[i].mode;
+		inode = rpc_get_inode(dir->i_sb, mode);
+		if (!inode) {
+			dput(dentry);
+			goto out_bad;
+		}
+		inode->i_ino = i;
+		if (files[i].i_fop)
+			inode->i_fop = files[i].i_fop;
+		if (private)
+			rpc_inode_setowner(inode, private);
+		if (S_ISDIR(mode))
+			dir->i_nlink++;
+		d_add(dentry, inode);
+	}
+	up(&dir->i_sem);
+	return 0;
+out_bad:
+	up(&dir->i_sem);
+	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
+			__FILE__, __FUNCTION__, parent->d_name.name);
+	return -ENOMEM;
+}
+
+static int
+__rpc_mkdir(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;
+}
+
+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)
+		return ERR_PTR(error);
+	dir = nd->dentry->d_inode;
+	down(&dir->i_sem);
+	dentry = lookup_hash(&nd->last, nd->dentry);
+	if (IS_ERR(dentry))
+		goto out_err;
+	if (dentry->d_inode) {
+		dput(dentry);
+		dentry = ERR_PTR(-EEXIST);
+		goto out_err;
+	}
+	return dentry;
+out_err:
+	up(&dir->i_sem);
+	rpc_release_path(nd);
+	return dentry;
+}
+
+
+struct dentry *
+rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
+{
+	struct nameidata nd;
+	struct dentry *dentry;
+	struct inode *dir;
+	int error;
+
+	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);
+	return dentry;
+err_depopulate:
+	rpc_depopulate(dentry);
+	__rpc_rmdir(dir, dentry);
+err_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;
+}
+
+int
+rpc_rmdir(char *path)
+{
+	struct nameidata nd;
+	struct dentry *dentry;
+	struct inode *dir;
+	int error;
+
+	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;
+}
+
+struct dentry *
+rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
+{
+	struct nameidata nd;
+	struct dentry *dentry;
+	struct inode *dir, *inode;
+	struct rpc_inode *rpci;
+
+	dentry = rpc_lookup_negative(path, &nd);
+	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;
+	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;
+	inode_dir_notify(dir, DN_CREATE);
+out:
+	up(&dir->i_sem);
+	rpc_release_path(&nd);
+	return dentry;
+err_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;
+}
+
+int
+rpc_unlink(char *path)
+{
+	struct nameidata nd;
+	struct dentry *dentry;
+	struct inode *dir;
+	int error;
+
+	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);
+	if (dentry->d_inode) {
+		rpc_close_pipes(dentry->d_inode);
+		rpc_inode_setowner(dentry->d_inode, NULL);
+		error = simple_unlink(dir, dentry);
+	}
+	dput(dentry);
+	inode_dir_notify(dir, DN_DELETE);
+out_release:
+	up(&dir->i_sem);
+	rpc_release_path(&nd);
+	return error;
+}
+
+/*
+ * populate the filesystem
+ */
+static struct super_operations s_ops = {
+	.alloc_inode	= rpc_alloc_inode,
+	.destroy_inode	= rpc_destroy_inode,
+	.statfs		= simple_statfs,
+};
+
+#define RPCAUTH_GSSMAGIC 0x67596969
+
+static int
+rpc_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct inode *inode;
+	struct dentry *root;
+
+	sb->s_blocksize = PAGE_CACHE_SIZE;
+	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+	sb->s_magic = RPCAUTH_GSSMAGIC;
+	sb->s_op = &s_ops;
+	sb->s_time_gran = 1;
+
+	inode = rpc_get_inode(sb, S_IFDIR | 0755);
+	if (!inode)
+		return -ENOMEM;
+	root = d_alloc_root(inode);
+	if (!root) {
+		iput(inode);
+		return -ENOMEM;
+	}
+	if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
+		goto out;
+	sb->s_root = root;
+	return 0;
+out:
+	d_genocide(root);
+	dput(root);
+	return -ENOMEM;
+}
+
+static struct super_block *
+rpc_get_sb(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *data)
+{
+	return get_sb_single(fs_type, flags, data, rpc_fill_super);
+}
+
+static struct file_system_type rpc_pipe_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "rpc_pipefs",
+	.get_sb		= rpc_get_sb,
+	.kill_sb	= kill_litter_super,
+};
+
+static void
+init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
+{
+	struct rpc_inode *rpci = (struct rpc_inode *) foo;
+
+	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR) {
+		inode_init_once(&rpci->vfs_inode);
+		rpci->private = NULL;
+		rpci->nreaders = 0;
+		rpci->nwriters = 0;
+		INIT_LIST_HEAD(&rpci->in_upcall);
+		INIT_LIST_HEAD(&rpci->pipe);
+		rpci->pipelen = 0;
+		init_waitqueue_head(&rpci->waitq);
+		INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
+		rpci->ops = NULL;
+	}
+}
+
+int register_rpc_pipefs(void)
+{
+	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
+                                             sizeof(struct rpc_inode),
+                                             0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
+                                             init_once, NULL);
+	if (!rpc_inode_cachep)
+		return -ENOMEM;
+	register_filesystem(&rpc_pipe_fs_type);
+	return 0;
+}
+
+void unregister_rpc_pipefs(void)
+{
+	if (kmem_cache_destroy(rpc_inode_cachep))
+		printk(KERN_WARNING "RPC: unable to free inode cache\n");
+	unregister_filesystem(&rpc_pipe_fs_type);
+}