initial_commit

1 files changed, 1086 insertions, 0 deletions

diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
new file mode 100644
index 00000000..72bc5368
--- /dev/null
+++ b/net/sunrpc/rpc_pipe.c
@@ -0,0 +1,1086 @@
+/*
+ * net/sunrpc/rpc_pipe.c
+ *
+ * Userland/kernel interface for rpcauth_gss.
+ * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
+ * and fs/sysfs/inode.c
+ *
+ * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
+ *
+ */
+#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/fsnotify.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>
+#include <linux/sunrpc/cache.h>
+
+static struct vfsmount *rpc_mnt __read_mostly;
+static int rpc_mount_count;
+
+static struct file_system_type rpc_pipe_fs_type;
+
+
+static struct kmem_cache *rpc_inode_cachep __read_mostly;
+
+#define RPC_UPCALL_TIMEOUT (30*HZ)
+
+static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
+		void (*destroy_msg)(struct rpc_pipe_msg *), int err)
+{
+	struct rpc_pipe_msg *msg;
+
+	if (list_empty(head))
+		return;
+	do {
+		msg = list_entry(head->next, struct rpc_pipe_msg, list);
+		list_del_init(&msg->list);
+		msg->errno = err;
+		destroy_msg(msg);
+	} while (!list_empty(head));
+	wake_up(&rpci->waitq);
+}
+
+static void
+rpc_timeout_upcall_queue(struct work_struct *work)
+{
+	LIST_HEAD(free_list);
+	struct rpc_inode *rpci =
+		container_of(work, struct rpc_inode, queue_timeout.work);
+	struct inode *inode = &rpci->vfs_inode;
+	void (*destroy_msg)(struct rpc_pipe_msg *);
+
+	spin_lock(&inode->i_lock);
+	if (rpci->ops == NULL) {
+		spin_unlock(&inode->i_lock);
+		return;
+	}
+	destroy_msg = rpci->ops->destroy_msg;
+	if (rpci->nreaders == 0) {
+		list_splice_init(&rpci->pipe, &free_list);
+		rpci->pipelen = 0;
+	}
+	spin_unlock(&inode->i_lock);
+	rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
+}
+
+/**
+ * rpc_queue_upcall - queue an upcall message to userspace
+ * @inode: inode of upcall pipe on which to queue given message
+ * @msg: message to queue
+ *
+ * Call with an @inode created by rpc_mkpipe() to queue an upcall.
+ * A userspace process may then later read the upcall by performing a
+ * read on an open file for this inode.  It is up to the caller to
+ * initialize the fields of @msg (other than @msg->list) appropriately.
+ */
+int
+rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	int res = -EPIPE;
+
+	spin_lock(&inode->i_lock);
+	if (rpci->ops == NULL)
+		goto out;
+	if (rpci->nreaders) {
+		list_add_tail(&msg->list, &rpci->pipe);
+		rpci->pipelen += msg->len;
+		res = 0;
+	} else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
+		if (list_empty(&rpci->pipe))
+			queue_delayed_work(rpciod_workqueue,
+					&rpci->queue_timeout,
+					RPC_UPCALL_TIMEOUT);
+		list_add_tail(&msg->list, &rpci->pipe);
+		rpci->pipelen += msg->len;
+		res = 0;
+	}
+out:
+	spin_unlock(&inode->i_lock);
+	wake_up(&rpci->waitq);
+	return res;
+}
+EXPORT_SYMBOL_GPL(rpc_queue_upcall);
+
+static inline void
+rpc_inode_setowner(struct inode *inode, void *private)
+{
+	RPC_I(inode)->private = private;
+}
+
+static void
+rpc_close_pipes(struct inode *inode)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	const struct rpc_pipe_ops *ops;
+	int need_release;
+
+	mutex_lock(&inode->i_mutex);
+	ops = rpci->ops;
+	if (ops != NULL) {
+		LIST_HEAD(free_list);
+		spin_lock(&inode->i_lock);
+		need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
+		rpci->nreaders = 0;
+		list_splice_init(&rpci->in_upcall, &free_list);
+		list_splice_init(&rpci->pipe, &free_list);
+		rpci->pipelen = 0;
+		rpci->ops = NULL;
+		spin_unlock(&inode->i_lock);
+		rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
+		rpci->nwriters = 0;
+		if (need_release && ops->release_pipe)
+			ops->release_pipe(inode);
+		cancel_delayed_work_sync(&rpci->queue_timeout);
+	}
+	rpc_inode_setowner(inode, NULL);
+	mutex_unlock(&inode->i_mutex);
+}
+
+static struct inode *
+rpc_alloc_inode(struct super_block *sb)
+{
+	struct rpc_inode *rpci;
+	rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
+	if (!rpci)
+		return NULL;
+	return &rpci->vfs_inode;
+}
+
+static void
+rpc_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	INIT_LIST_HEAD(&inode->i_dentry);
+	kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
+}
+
+static void
+rpc_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, rpc_i_callback);
+}
+
+static int
+rpc_pipe_open(struct inode *inode, struct file *filp)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	int first_open;
+	int res = -ENXIO;
+
+	mutex_lock(&inode->i_mutex);
+	if (rpci->ops == NULL)
+		goto out;
+	first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
+	if (first_open && rpci->ops->open_pipe) {
+		res = rpci->ops->open_pipe(inode);
+		if (res)
+			goto out;
+	}
+	if (filp->f_mode & FMODE_READ)
+		rpci->nreaders++;
+	if (filp->f_mode & FMODE_WRITE)
+		rpci->nwriters++;
+	res = 0;
+out:
+	mutex_unlock(&inode->i_mutex);
+	return res;
+}
+
+static int
+rpc_pipe_release(struct inode *inode, struct file *filp)
+{
+	struct rpc_inode *rpci = RPC_I(inode);
+	struct rpc_pipe_msg *msg;
+	int last_close;
+
+	mutex_lock(&inode->i_mutex);
+	if (rpci->ops == NULL)
+		goto out;
+	msg = filp->private_data;
+	if (msg != NULL) {
+		spin_lock(&inode->i_lock);
+		msg->errno = -EAGAIN;
+		list_del_init(&msg->list);
+		spin_unlock(&inode->i_lock);
+		rpci->ops->destroy_msg(msg);
+	}
+	if (filp->f_mode & FMODE_WRITE)
+		rpci->nwriters --;
+	if (filp->f_mode & FMODE_READ) {
+		rpci->nreaders --;
+		if (rpci->nreaders == 0) {
+			LIST_HEAD(free_list);
+			spin_lock(&inode->i_lock);
+			list_splice_init(&rpci->pipe, &free_list);
+			rpci->pipelen = 0;
+			spin_unlock(&inode->i_lock);
+			rpc_purge_list(rpci, &free_list,
+					rpci->ops->destroy_msg, -EAGAIN);
+		}
+	}
+	last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
+	if (last_close && rpci->ops->release_pipe)
+		rpci->ops->release_pipe(inode);
+out:
+	mutex_unlock(&inode->i_mutex);
+	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_path.dentry->d_inode;
+	struct rpc_inode *rpci = RPC_I(inode);
+	struct rpc_pipe_msg *msg;
+	int res = 0;
+
+	mutex_lock(&inode->i_mutex);
+	if (rpci->ops == NULL) {
+		res = -EPIPE;
+		goto out_unlock;
+	}
+	msg = filp->private_data;
+	if (msg == NULL) {
+		spin_lock(&inode->i_lock);
+		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;
+		}
+		spin_unlock(&inode->i_lock);
+		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;
+		spin_lock(&inode->i_lock);
+		list_del_init(&msg->list);
+		spin_unlock(&inode->i_lock);
+		rpci->ops->destroy_msg(msg);
+	}
+out_unlock:
+	mutex_unlock(&inode->i_mutex);
+	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_path.dentry->d_inode;
+	struct rpc_inode *rpci = RPC_I(inode);
+	int res;
+
+	mutex_lock(&inode->i_mutex);
+	res = -EPIPE;
+	if (rpci->ops != NULL)
+		res = rpci->ops->downcall(filp, buf, len);
+	mutex_unlock(&inode->i_mutex);
+	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_path.dentry->d_inode);
+	poll_wait(filp, &rpci->waitq, wait);
+
+	mask = POLLOUT | POLLWRNORM;
+	if (rpci->ops == NULL)
+		mask |= POLLERR | POLLHUP;
+	if (filp->private_data || !list_empty(&rpci->pipe))
+		mask |= POLLIN | POLLRDNORM;
+	return mask;
+}
+
+static long
+rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct rpc_inode *rpci = RPC_I(inode);
+	int len;
+
+	switch (cmd) {
+	case FIONREAD:
+		spin_lock(&inode->i_lock);
+		if (rpci->ops == NULL) {
+			spin_unlock(&inode->i_lock);
+			return -EPIPE;
+		}
+		len = rpci->pipelen;
+		if (filp->private_data) {
+			struct rpc_pipe_msg *msg;
+			msg = filp->private_data;
+			len += msg->len - msg->copied;
+		}
+		spin_unlock(&inode->i_lock);
+		return put_user(len, (int __user *)arg);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct file_operations rpc_pipe_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.read		= rpc_pipe_read,
+	.write		= rpc_pipe_write,
+	.poll		= rpc_pipe_poll,
+	.unlocked_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: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
+	seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
+	seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
+	return 0;
+}
+
+static int
+rpc_info_open(struct inode *inode, struct file *file)
+{
+	struct rpc_clnt *clnt = NULL;
+	int ret = single_open(file, rpc_show_info, NULL);
+
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+
+		spin_lock(&file->f_path.dentry->d_lock);
+		if (!d_unhashed(file->f_path.dentry))
+			clnt = RPC_I(inode)->private;
+		if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
+			spin_unlock(&file->f_path.dentry->d_lock);
+			m->private = clnt;
+		} else {
+			spin_unlock(&file->f_path.dentry->d_lock);
+			single_release(inode, file);
+			ret = -EINVAL;
+		}
+	}
+	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 const struct file_operations rpc_info_operations = {
+	.owner		= THIS_MODULE,
+	.open		= rpc_info_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= rpc_info_release,
+};
+
+
+/*
+ * Description of fs contents.
+ */
+struct rpc_filelist {
+	const char *name;
+	const struct file_operations *i_fop;
+	umode_t mode;
+};
+
+struct vfsmount *rpc_get_mount(void)
+{
+	int err;
+
+	err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mnt, &rpc_mount_count);
+	if (err != 0)
+		return ERR_PTR(err);
+	return rpc_mnt;
+}
+EXPORT_SYMBOL_GPL(rpc_get_mount);
+
+void rpc_put_mount(void)
+{
+	simple_release_fs(&rpc_mnt, &rpc_mount_count);
+}
+EXPORT_SYMBOL_GPL(rpc_put_mount);
+
+static int rpc_delete_dentry(const struct dentry *dentry)
+{
+	return 1;
+}
+
+static const struct dentry_operations rpc_dentry_operations = {
+	.d_delete = rpc_delete_dentry,
+};
+
+static struct inode *
+rpc_get_inode(struct super_block *sb, umode_t mode)
+{
+	struct inode *inode = new_inode(sb);
+	if (!inode)
+		return NULL;
+	inode->i_ino = get_next_ino();
+	inode->i_mode = mode;
+	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;
+			inc_nlink(inode);
+		default:
+			break;
+	}
+	return inode;
+}
+
+static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
+			       umode_t mode,
+			       const struct file_operations *i_fop,
+			       void *private)
+{
+	struct inode *inode;
+
+	d_drop(dentry);
+	inode = rpc_get_inode(dir->i_sb, mode);
+	if (!inode)
+		goto out_err;
+	inode->i_ino = iunique(dir->i_sb, 100);
+	if (i_fop)
+		inode->i_fop = i_fop;
+	if (private)
+		rpc_inode_setowner(inode, private);
+	d_add(dentry, inode);
+	return 0;
+out_err:
+	printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
+			__FILE__, __func__, dentry->d_name.name);
+	dput(dentry);
+	return -ENOMEM;
+}
+
+static int __rpc_create(struct inode *dir, struct dentry *dentry,
+			umode_t mode,
+			const struct file_operations *i_fop,
+			void *private)
+{
+	int err;
+
+	err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
+	if (err)
+		return err;
+	fsnotify_create(dir, dentry);
+	return 0;
+}
+
+static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
+		       umode_t mode,
+		       const struct file_operations *i_fop,
+		       void *private)
+{
+	int err;
+
+	err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
+	if (err)
+		return err;
+	inc_nlink(dir);
+	fsnotify_mkdir(dir, dentry);
+	return 0;
+}
+
+static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
+			umode_t mode,
+			const struct file_operations *i_fop,
+			void *private,
+			const struct rpc_pipe_ops *ops,
+			int flags)
+{
+	struct rpc_inode *rpci;
+	int err;
+
+	err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
+	if (err)
+		return err;
+	rpci = RPC_I(dentry->d_inode);
+	rpci->nkern_readwriters = 1;
+	rpci->private = private;
+	rpci->flags = flags;
+	rpci->ops = ops;
+	fsnotify_create(dir, dentry);
+	return 0;
+}
+
+static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int ret;
+
+	dget(dentry);
+	ret = simple_rmdir(dir, dentry);
+	d_delete(dentry);
+	dput(dentry);
+	return ret;
+}
+
+static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int ret;
+
+	dget(dentry);
+	ret = simple_unlink(dir, dentry);
+	d_delete(dentry);
+	dput(dentry);
+	return ret;
+}
+
+static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct rpc_inode *rpci = RPC_I(inode);
+
+	rpci->nkern_readwriters--;
+	if (rpci->nkern_readwriters != 0)
+		return 0;
+	rpc_close_pipes(inode);
+	return __rpc_unlink(dir, dentry);
+}
+
+static struct dentry *__rpc_lookup_create(struct dentry *parent,
+					  struct qstr *name)
+{
+	struct dentry *dentry;
+
+	dentry = d_lookup(parent, name);
+	if (!dentry) {
+		dentry = d_alloc(parent, name);
+		if (!dentry) {
+			dentry = ERR_PTR(-ENOMEM);
+			goto out_err;
+		}
+	}
+	if (!dentry->d_inode)
+		d_set_d_op(dentry, &rpc_dentry_operations);
+out_err:
+	return dentry;
+}
+
+static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
+					  struct qstr *name)
+{
+	struct dentry *dentry;
+
+	dentry = __rpc_lookup_create(parent, name);
+	if (IS_ERR(dentry))
+		return dentry;
+	if (dentry->d_inode == NULL)
+		return dentry;
+	dput(dentry);
+	return ERR_PTR(-EEXIST);
+}
+
+/*
+ * FIXME: This probably has races.
+ */
+static void __rpc_depopulate(struct dentry *parent,
+			     const struct rpc_filelist *files,
+			     int start, int eof)
+{
+	struct inode *dir = parent->d_inode;
+	struct dentry *dentry;
+	struct qstr name;
+	int i;
+
+	for (i = start; i < eof; i++) {
+		name.name = files[i].name;
+		name.len = strlen(files[i].name);
+		name.hash = full_name_hash(name.name, name.len);
+		dentry = d_lookup(parent, &name);
+
+		if (dentry == NULL)
+			continue;
+		if (dentry->d_inode == NULL)
+			goto next;
+		switch (dentry->d_inode->i_mode & S_IFMT) {
+			default:
+				BUG();
+			case S_IFREG:
+				__rpc_unlink(dir, dentry);
+				break;
+			case S_IFDIR:
+				__rpc_rmdir(dir, dentry);
+		}
+next:
+		dput(dentry);
+	}
+}
+
+static void rpc_depopulate(struct dentry *parent,
+			   const struct rpc_filelist *files,
+			   int start, int eof)
+{
+	struct inode *dir = parent->d_inode;
+
+	mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
+	__rpc_depopulate(parent, files, start, eof);
+	mutex_unlock(&dir->i_mutex);
+}
+
+static int rpc_populate(struct dentry *parent,
+			const struct rpc_filelist *files,
+			int start, int eof,
+			void *private)
+{
+	struct inode *dir = parent->d_inode;
+	struct dentry *dentry;
+	int i, err;
+
+	mutex_lock(&dir->i_mutex);
+	for (i = start; i < eof; i++) {
+		struct qstr q;
+
+		q.name = files[i].name;
+		q.len = strlen(files[i].name);
+		q.hash = full_name_hash(q.name, q.len);
+		dentry = __rpc_lookup_create_exclusive(parent, &q);
+		err = PTR_ERR(dentry);
+		if (IS_ERR(dentry))
+			goto out_bad;
+		switch (files[i].mode & S_IFMT) {
+			default:
+				BUG();
+			case S_IFREG:
+				err = __rpc_create(dir, dentry,
+						files[i].mode,
+						files[i].i_fop,
+						private);
+				break;
+			case S_IFDIR:
+				err = __rpc_mkdir(dir, dentry,
+						files[i].mode,
+						NULL,
+						private);
+		}
+		if (err != 0)
+			goto out_bad;
+	}
+	mutex_unlock(&dir->i_mutex);
+	return 0;
+out_bad:
+	__rpc_depopulate(parent, files, start, eof);
+	mutex_unlock(&dir->i_mutex);
+	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
+			__FILE__, __func__, parent->d_name.name);
+	return err;
+}
+
+static struct dentry *rpc_mkdir_populate(struct dentry *parent,
+		struct qstr *name, umode_t mode, void *private,
+		int (*populate)(struct dentry *, void *), void *args_populate)
+{
+	struct dentry *dentry;
+	struct inode *dir = parent->d_inode;
+	int error;
+
+	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+	dentry = __rpc_lookup_create_exclusive(parent, name);
+	if (IS_ERR(dentry))
+		goto out;
+	error = __rpc_mkdir(dir, dentry, mode, NULL, private);
+	if (error != 0)
+		goto out_err;
+	if (populate != NULL) {
+		error = populate(dentry, args_populate);
+		if (error)
+			goto err_rmdir;
+	}
+out:
+	mutex_unlock(&dir->i_mutex);
+	return dentry;
+err_rmdir:
+	__rpc_rmdir(dir, dentry);
+out_err:
+	dentry = ERR_PTR(error);
+	goto out;
+}
+
+static int rpc_rmdir_depopulate(struct dentry *dentry,
+		void (*depopulate)(struct dentry *))
+{
+	struct dentry *parent;
+	struct inode *dir;
+	int error;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+	if (depopulate != NULL)
+		depopulate(dentry);
+	error = __rpc_rmdir(dir, dentry);
+	mutex_unlock(&dir->i_mutex);
+	dput(parent);
+	return error;
+}
+
+/**
+ * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
+ * @parent: dentry of directory to create new "pipe" in
+ * @name: name of pipe
+ * @private: private data to associate with the pipe, for the caller's use
+ * @ops: operations defining the behavior of the pipe: upcall, downcall,
+ *	release_pipe, open_pipe, and destroy_msg.
+ * @flags: rpc_inode flags
+ *
+ * Data is made available for userspace to read by calls to
+ * rpc_queue_upcall().  The actual reads will result in calls to
+ * @ops->upcall, which will be called with the file pointer,
+ * message, and userspace buffer to copy to.
+ *
+ * Writes can come at any time, and do not necessarily have to be
+ * responses to upcalls.  They will result in calls to @msg->downcall.
+ *
+ * The @private argument passed here will be available to all these methods
+ * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
+ */
+struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
+			  void *private, const struct rpc_pipe_ops *ops,
+			  int flags)
+{
+	struct dentry *dentry;
+	struct inode *dir = parent->d_inode;
+	umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
+	struct qstr q;
+	int err;
+
+	if (ops->upcall == NULL)
+		umode &= ~S_IRUGO;
+	if (ops->downcall == NULL)
+		umode &= ~S_IWUGO;
+
+	q.name = name;
+	q.len = strlen(name);
+	q.hash = full_name_hash(q.name, q.len),
+
+	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+	dentry = __rpc_lookup_create(parent, &q);
+	if (IS_ERR(dentry))
+		goto out;
+	if (dentry->d_inode) {
+		struct rpc_inode *rpci = RPC_I(dentry->d_inode);
+		if (rpci->private != private ||
+				rpci->ops != ops ||
+				rpci->flags != flags) {
+			dput (dentry);
+			err = -EBUSY;
+			goto out_err;
+		}
+		rpci->nkern_readwriters++;
+		goto out;
+	}
+
+	err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
+			   private, ops, flags);
+	if (err)
+		goto out_err;
+out:
+	mutex_unlock(&dir->i_mutex);
+	return dentry;
+out_err:
+	dentry = ERR_PTR(err);
+	printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
+			__FILE__, __func__, parent->d_name.name, name,
+			err);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(rpc_mkpipe);
+
+/**
+ * rpc_unlink - remove a pipe
+ * @dentry: dentry for the pipe, as returned from rpc_mkpipe
+ *
+ * After this call, lookups will no longer find the pipe, and any
+ * attempts to read or write using preexisting opens of the pipe will
+ * return -EPIPE.
+ */
+int
+rpc_unlink(struct dentry *dentry)
+{
+	struct dentry *parent;
+	struct inode *dir;
+	int error = 0;
+
+	parent = dget_parent(dentry);
+	dir = parent->d_inode;
+	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
+	error = __rpc_rmpipe(dir, dentry);
+	mutex_unlock(&dir->i_mutex);
+	dput(parent);
+	return error;
+}
+EXPORT_SYMBOL_GPL(rpc_unlink);
+
+enum {
+	RPCAUTH_info,
+	RPCAUTH_EOF
+};
+
+static const struct rpc_filelist authfiles[] = {
+	[RPCAUTH_info] = {
+		.name = "info",
+		.i_fop = &rpc_info_operations,
+		.mode = S_IFREG | S_IRUSR,
+	},
+};
+
+static int rpc_clntdir_populate(struct dentry *dentry, void *private)
+{
+	return rpc_populate(dentry,
+			    authfiles, RPCAUTH_info, RPCAUTH_EOF,
+			    private);
+}
+
+static void rpc_clntdir_depopulate(struct dentry *dentry)
+{
+	rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
+}
+
+/**
+ * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
+ * @dentry: dentry from the rpc_pipefs root to the new directory
+ * @name: &struct qstr for the name
+ * @rpc_client: rpc client to associate with this directory
+ *
+ * This creates a directory at the given @path associated with
+ * @rpc_clnt, which will contain a file named "info" with some basic
+ * information about the client, together with any "pipes" that may
+ * later be created using rpc_mkpipe().
+ */
+struct dentry *rpc_create_client_dir(struct dentry *dentry,
+				   struct qstr *name,
+				   struct rpc_clnt *rpc_client)
+{
+	return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
+			rpc_clntdir_populate, rpc_client);
+}
+
+/**
+ * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
+ * @dentry: directory to remove
+ */
+int rpc_remove_client_dir(struct dentry *dentry)
+{
+	return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
+}
+
+static const struct rpc_filelist cache_pipefs_files[3] = {
+	[0] = {
+		.name = "channel",
+		.i_fop = &cache_file_operations_pipefs,
+		.mode = S_IFREG|S_IRUSR|S_IWUSR,
+	},
+	[1] = {
+		.name = "content",
+		.i_fop = &content_file_operations_pipefs,
+		.mode = S_IFREG|S_IRUSR,
+	},
+	[2] = {
+		.name = "flush",
+		.i_fop = &cache_flush_operations_pipefs,
+		.mode = S_IFREG|S_IRUSR|S_IWUSR,
+	},
+};
+
+static int rpc_cachedir_populate(struct dentry *dentry, void *private)
+{
+	return rpc_populate(dentry,
+			    cache_pipefs_files, 0, 3,
+			    private);
+}
+
+static void rpc_cachedir_depopulate(struct dentry *dentry)
+{
+	rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
+}
+
+struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
+				    mode_t umode, struct cache_detail *cd)
+{
+	return rpc_mkdir_populate(parent, name, umode, NULL,
+			rpc_cachedir_populate, cd);
+}
+
+void rpc_remove_cache_dir(struct dentry *dentry)
+{
+	rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
+}
+
+/*
+ * populate the filesystem
+ */
+static const struct super_operations s_ops = {
+	.alloc_inode	= rpc_alloc_inode,
+	.destroy_inode	= rpc_destroy_inode,
+	.statfs		= simple_statfs,
+};
+
+#define RPCAUTH_GSSMAGIC 0x67596969
+
+/*
+ * We have a single directory with 1 node in it.
+ */
+enum {
+	RPCAUTH_lockd,
+	RPCAUTH_mount,
+	RPCAUTH_nfs,
+	RPCAUTH_portmap,
+	RPCAUTH_statd,
+	RPCAUTH_nfsd4_cb,
+	RPCAUTH_cache,
+	RPCAUTH_RootEOF
+};
+
+static const 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,
+	},
+	[RPCAUTH_nfsd4_cb] = {
+		.name = "nfsd4_cb",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+	[RPCAUTH_cache] = {
+		.name = "cache",
+		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
+	},
+};
+
+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;
+	sb->s_root = root = d_alloc_root(inode);
+	if (!root) {
+		iput(inode);
+		return -ENOMEM;
+	}
+	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
+		return -ENOMEM;
+	return 0;
+}
+
+static struct dentry *
+rpc_mount(struct file_system_type *fs_type,
+		int flags, const char *dev_name, void *data)
+{
+	return mount_single(fs_type, flags, data, rpc_fill_super);
+}
+
+static struct file_system_type rpc_pipe_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "rpc_pipefs",
+	.mount		= rpc_mount,
+	.kill_sb	= kill_litter_super,
+};
+
+static void
+init_once(void *foo)
+{
+	struct rpc_inode *rpci = (struct rpc_inode *) foo;
+
+	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->in_downcall);
+	INIT_LIST_HEAD(&rpci->pipe);
+	rpci->pipelen = 0;
+	init_waitqueue_head(&rpci->waitq);
+	INIT_DELAYED_WORK(&rpci->queue_timeout,
+			    rpc_timeout_upcall_queue);
+	rpci->ops = NULL;
+}
+
+int register_rpc_pipefs(void)
+{
+	int err;
+
+	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
+				sizeof(struct rpc_inode),
+				0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD),
+				init_once);
+	if (!rpc_inode_cachep)
+		return -ENOMEM;
+	err = register_filesystem(&rpc_pipe_fs_type);
+	if (err) {
+		kmem_cache_destroy(rpc_inode_cachep);
+		return err;
+	}
+
+	return 0;
+}
+
+void unregister_rpc_pipefs(void)
+{
+	kmem_cache_destroy(rpc_inode_cachep);
+	unregister_filesystem(&rpc_pipe_fs_type);
+}