rpc_pipe.c 24.9 KB
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/*
 * net/sunrpc/rpc_pipe.c
 *
 * Userland/kernel interface for rpcauth_gss.
 * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
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 * and fs/sysfs/inode.c
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 *
 * 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>
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#include <linux/fsnotify.h>
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#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>
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#include <linux/sunrpc/cache.h>
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#include <linux/smp_lock.h>
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static struct vfsmount *rpc_mount __read_mostly;
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static int rpc_mount_count;

static struct file_system_type rpc_pipe_fs_type;


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static struct kmem_cache *rpc_inode_cachep __read_mostly;
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#define RPC_UPCALL_TIMEOUT (30*HZ)

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static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
		void (*destroy_msg)(struct rpc_pipe_msg *), int err)
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{
	struct rpc_pipe_msg *msg;

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	if (list_empty(head))
		return;
	do {
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		msg = list_entry(head->next, struct rpc_pipe_msg, list);
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		list_del_init(&msg->list);
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		msg->errno = err;
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		destroy_msg(msg);
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	} while (!list_empty(head));
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	wake_up(&rpci->waitq);
}

static void
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rpc_timeout_upcall_queue(struct work_struct *work)
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{
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	LIST_HEAD(free_list);
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	struct rpc_inode *rpci =
		container_of(work, struct rpc_inode, queue_timeout.work);
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	struct inode *inode = &rpci->vfs_inode;
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	void (*destroy_msg)(struct rpc_pipe_msg *);
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	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);
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}

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/**
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 * rpc_queue_upcall - queue an upcall message to userspace
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 * @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.
 */
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int
rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
{
	struct rpc_inode *rpci = RPC_I(inode);
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	int res = -EPIPE;
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	spin_lock(&inode->i_lock);
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	if (rpci->ops == NULL)
		goto out;
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	if (rpci->nreaders) {
		list_add_tail(&msg->list, &rpci->pipe);
		rpci->pipelen += msg->len;
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		res = 0;
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	} else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
		if (list_empty(&rpci->pipe))
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			queue_delayed_work(rpciod_workqueue,
					&rpci->queue_timeout,
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					RPC_UPCALL_TIMEOUT);
		list_add_tail(&msg->list, &rpci->pipe);
		rpci->pipelen += msg->len;
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		res = 0;
	}
out:
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	spin_unlock(&inode->i_lock);
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	wake_up(&rpci->waitq);
	return res;
}
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EXPORT_SYMBOL_GPL(rpc_queue_upcall);
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static inline void
rpc_inode_setowner(struct inode *inode, void *private)
{
	RPC_I(inode)->private = private;
}

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static void
rpc_close_pipes(struct inode *inode)
{
	struct rpc_inode *rpci = RPC_I(inode);
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	const struct rpc_pipe_ops *ops;
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	int need_release;
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	mutex_lock(&inode->i_mutex);
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	ops = rpci->ops;
	if (ops != NULL) {
		LIST_HEAD(free_list);
		spin_lock(&inode->i_lock);
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		need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
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		rpci->nreaders = 0;
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		list_splice_init(&rpci->in_upcall, &free_list);
		list_splice_init(&rpci->pipe, &free_list);
		rpci->pipelen = 0;
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		rpci->ops = NULL;
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		spin_unlock(&inode->i_lock);
		rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
		rpci->nwriters = 0;
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		if (need_release && ops->release_pipe)
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			ops->release_pipe(inode);
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		cancel_delayed_work_sync(&rpci->queue_timeout);
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	}
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	rpc_inode_setowner(inode, NULL);
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	mutex_unlock(&inode->i_mutex);
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}

static struct inode *
rpc_alloc_inode(struct super_block *sb)
{
	struct rpc_inode *rpci;
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	rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
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	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);
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	int first_open;
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	int res = -ENXIO;

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	mutex_lock(&inode->i_mutex);
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	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;
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	}
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	if (filp->f_mode & FMODE_READ)
		rpci->nreaders++;
	if (filp->f_mode & FMODE_WRITE)
		rpci->nwriters++;
	res = 0;
out:
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	mutex_unlock(&inode->i_mutex);
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	return res;
}

static int
rpc_pipe_release(struct inode *inode, struct file *filp)
{
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	struct rpc_inode *rpci = RPC_I(inode);
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	struct rpc_pipe_msg *msg;
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	int last_close;
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	mutex_lock(&inode->i_mutex);
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	if (rpci->ops == NULL)
		goto out;
	msg = (struct rpc_pipe_msg *)filp->private_data;
	if (msg != NULL) {
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		spin_lock(&inode->i_lock);
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		msg->errno = -EAGAIN;
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		list_del_init(&msg->list);
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		spin_unlock(&inode->i_lock);
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		rpci->ops->destroy_msg(msg);
	}
	if (filp->f_mode & FMODE_WRITE)
		rpci->nwriters --;
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	if (filp->f_mode & FMODE_READ) {
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		rpci->nreaders --;
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		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);
		}
	}
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	last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
	if (last_close && rpci->ops->release_pipe)
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		rpci->ops->release_pipe(inode);
out:
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	mutex_unlock(&inode->i_mutex);
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	return 0;
}

static ssize_t
rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
{
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	struct inode *inode = filp->f_path.dentry->d_inode;
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	struct rpc_inode *rpci = RPC_I(inode);
	struct rpc_pipe_msg *msg;
	int res = 0;

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	mutex_lock(&inode->i_mutex);
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	if (rpci->ops == NULL) {
		res = -EPIPE;
		goto out_unlock;
	}
	msg = filp->private_data;
	if (msg == NULL) {
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		spin_lock(&inode->i_lock);
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		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;
		}
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		spin_unlock(&inode->i_lock);
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		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;
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		spin_lock(&inode->i_lock);
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		list_del_init(&msg->list);
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		spin_unlock(&inode->i_lock);
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		rpci->ops->destroy_msg(msg);
	}
out_unlock:
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	mutex_unlock(&inode->i_mutex);
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	return res;
}

static ssize_t
rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
{
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	struct inode *inode = filp->f_path.dentry->d_inode;
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	struct rpc_inode *rpci = RPC_I(inode);
	int res;

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	mutex_lock(&inode->i_mutex);
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	res = -EPIPE;
	if (rpci->ops != NULL)
		res = rpci->ops->downcall(filp, buf, len);
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	mutex_unlock(&inode->i_mutex);
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	return res;
}

static unsigned int
rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
{
	struct rpc_inode *rpci;
	unsigned int mask = 0;

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	rpci = RPC_I(filp->f_path.dentry->d_inode);
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	poll_wait(filp, &rpci->waitq, wait);

	mask = POLLOUT | POLLWRNORM;
	if (rpci->ops == NULL)
		mask |= POLLERR | POLLHUP;
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	if (filp->private_data || !list_empty(&rpci->pipe))
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		mask |= POLLIN | POLLRDNORM;
	return mask;
}

static int
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rpc_pipe_ioctl_unlocked(struct file *filp, unsigned int cmd, unsigned long arg)
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{
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	struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
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	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;
	}
}

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static long
rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	long ret;

	lock_kernel();
	ret = rpc_pipe_ioctl_unlocked(filp, cmd, arg);
	unlock_kernel();

	return ret;
}

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static const struct file_operations rpc_pipe_fops = {
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	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= rpc_pipe_read,
	.write		= rpc_pipe_write,
	.poll		= rpc_pipe_poll,
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	.unlocked_ioctl	= rpc_pipe_ioctl,
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	.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);
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	seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
	seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
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	seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
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	return 0;
}

static int
rpc_info_open(struct inode *inode, struct file *file)
{
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	struct rpc_clnt *clnt = NULL;
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	int ret = single_open(file, rpc_show_info, NULL);

	if (!ret) {
		struct seq_file *m = file->private_data;
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		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);
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			m->private = clnt;
		} else {
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			spin_unlock(&file->f_path.dentry->d_lock);
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			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);
}

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static const struct file_operations rpc_info_operations = {
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	.owner		= THIS_MODULE,
	.open		= rpc_info_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= rpc_info_release,
};


/*
 * Description of fs contents.
 */
struct rpc_filelist {
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	const char *name;
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	const struct file_operations *i_fop;
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	umode_t mode;
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};

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struct vfsmount *rpc_get_mount(void)
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{
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	int err;

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	err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
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	if (err != 0)
		return ERR_PTR(err);
	return rpc_mount;
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}
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EXPORT_SYMBOL_GPL(rpc_get_mount);
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void rpc_put_mount(void)
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{
	simple_release_fs(&rpc_mount, &rpc_mount_count);
}
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EXPORT_SYMBOL_GPL(rpc_put_mount);
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static int rpc_delete_dentry(struct dentry *dentry)
{
	return 1;
}

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static const struct dentry_operations rpc_dentry_operations = {
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	.d_delete = rpc_delete_dentry,
};

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static struct inode *
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rpc_get_inode(struct super_block *sb, umode_t mode)
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{
	struct inode *inode = new_inode(sb);
	if (!inode)
		return NULL;
	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;
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			inc_nlink(inode);
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		default:
			break;
	}
	return inode;
}

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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;

	BUG_ON(!d_unhashed(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;
}

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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;
}

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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;
}

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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;
}

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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);
}

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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)
		dentry->d_op = &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);
604 605
	if (IS_ERR(dentry))
		return dentry;
606 607 608 609 610 611
	if (dentry->d_inode == NULL)
		return dentry;
	dput(dentry);
	return ERR_PTR(-EEXIST);
}

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/*
 * FIXME: This probably has races.
 */
615 616 617
static void __rpc_depopulate(struct dentry *parent,
			     const struct rpc_filelist *files,
			     int start, int eof)
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{
	struct inode *dir = parent->d_inode;
620 621 622
	struct dentry *dentry;
	struct qstr name;
	int i;
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624 625 626 627 628 629 630
	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)
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			continue;
632 633 634 635 636 637 638
		if (dentry->d_inode == NULL)
			goto next;
		switch (dentry->d_inode->i_mode & S_IFMT) {
			default:
				BUG();
			case S_IFREG:
				__rpc_unlink(dir, dentry);
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				break;
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			case S_IFDIR:
				__rpc_rmdir(dir, dentry);
		}
next:
		dput(dentry);
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	}
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}

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);
656
	mutex_unlock(&dir->i_mutex);
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}

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static int rpc_populate(struct dentry *parent,
			const struct rpc_filelist *files,
			int start, int eof,
			void *private)
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{
664
	struct inode *dir = parent->d_inode;
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	struct dentry *dentry;
666
	int i, err;
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668
	mutex_lock(&dir->i_mutex);
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	for (i = start; i < eof; i++) {
670 671 672 673 674 675 676 677
		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))
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			goto out_bad;
679 680 681 682 683 684 685 686 687 688 689 690 691 692
		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);
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		}
694 695
		if (err != 0)
			goto out_bad;
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	}
697
	mutex_unlock(&dir->i_mutex);
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	return 0;
out_bad:
700
	__rpc_depopulate(parent, files, start, eof);
701
	mutex_unlock(&dir->i_mutex);
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	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
703
			__FILE__, __func__, parent->d_name.name);
704
	return err;
705
}
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707 708 709
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)
710 711
{
	struct dentry *dentry;
712
	struct inode *dir = parent->d_inode;
713 714
	int error;

715 716
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
	dentry = __rpc_lookup_create_exclusive(parent, name);
717
	if (IS_ERR(dentry))
718 719
		goto out;
	error = __rpc_mkdir(dir, dentry, mode, NULL, private);
720 721
	if (error != 0)
		goto out_err;
722 723 724 725 726
	if (populate != NULL) {
		error = populate(dentry, args_populate);
		if (error)
			goto err_rmdir;
	}
727
out:
728
	mutex_unlock(&dir->i_mutex);
729
	return dentry;
730
err_rmdir:
731
	__rpc_rmdir(dir, dentry);
732
out_err:
733 734
	dentry = ERR_PTR(error);
	goto out;
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}

737 738
static int rpc_rmdir_depopulate(struct dentry *dentry,
		void (*depopulate)(struct dentry *))
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{
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	struct dentry *parent;
741 742
	struct inode *dir;
	int error;
743

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	parent = dget_parent(dentry);
	dir = parent->d_inode;
746
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
747 748
	if (depopulate != NULL)
		depopulate(dentry);
749
	error = __rpc_rmdir(dir, dentry);
750
	mutex_unlock(&dir->i_mutex);
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	dput(parent);
752
	return error;
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}

755 756 757 758 759 760
/**
 * 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,
761
 *	release_pipe, open_pipe, and destroy_msg.
762
 * @flags: rpc_inode flags
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 *
 * 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.
 */
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struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
			  void *private, const struct rpc_pipe_ops *ops,
			  int flags)
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{
	struct dentry *dentry;
780
	struct inode *dir = parent->d_inode;
781
	umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
782
	struct qstr q;
783
	int err;
784 785 786 787 788

	if (ops->upcall == NULL)
		umode &= ~S_IRUGO;
	if (ops->downcall == NULL)
		umode &= ~S_IWUGO;
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	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);
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	if (IS_ERR(dentry))
797
		goto out;
798
	if (dentry->d_inode) {
799
		struct rpc_inode *rpci = RPC_I(dentry->d_inode);
800 801 802 803
		if (rpci->private != private ||
				rpci->ops != ops ||
				rpci->flags != flags) {
			dput (dentry);
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			err = -EBUSY;
			goto out_err;
806
		}
807
		rpci->nkern_readwriters++;
808 809
		goto out;
	}
810 811

	err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
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			   private, ops, flags);
813 814
	if (err)
		goto out_err;
815
out:
816
	mutex_unlock(&dir->i_mutex);
817
	return dentry;
818 819
out_err:
	dentry = ERR_PTR(err);
820
	printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
821
			__FILE__, __func__, parent->d_name.name, name,
822
			err);
823
	goto out;
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}
825
EXPORT_SYMBOL_GPL(rpc_mkpipe);
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827 828 829 830 831 832 833 834
/**
 * 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.
 */
835
int
836
rpc_unlink(struct dentry *dentry)
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{
838
	struct dentry *parent;
839
	struct inode *dir;
840
	int error = 0;
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842 843
	parent = dget_parent(dentry);
	dir = parent->d_inode;
844
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
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	error = __rpc_rmpipe(dir, dentry);
846
	mutex_unlock(&dir->i_mutex);
847
	dput(parent);
848
	return error;
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}
850
EXPORT_SYMBOL_GPL(rpc_unlink);
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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);
}

877 878
/**
 * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
879 880
 * @dentry: dentry from the rpc_pipefs root to the new directory
 * @name: &struct qstr for the name
881 882 883 884 885 886 887
 * @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().
 */
888
struct dentry *rpc_create_client_dir(struct dentry *dentry,
889 890 891 892 893 894 895 896 897 898 899 900
				   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)
901
{
902
	return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
903 904
}

905 906 907 908
static const struct rpc_filelist cache_pipefs_files[3] = {
	[0] = {
		.name = "channel",
		.i_fop = &cache_file_operations_pipefs,
909
		.mode = S_IFREG|S_IRUSR|S_IWUSR,
910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946
	},
	[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);
}

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/*
 * populate the filesystem
 */
950
static const struct super_operations s_ops = {
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	.alloc_inode	= rpc_alloc_inode,
	.destroy_inode	= rpc_destroy_inode,
	.statfs		= simple_statfs,
};

#define RPCAUTH_GSSMAGIC 0x67596969

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/*
 * We have a single directory with 1 node in it.
 */
enum {
	RPCAUTH_lockd,
	RPCAUTH_mount,
	RPCAUTH_nfs,
	RPCAUTH_portmap,
	RPCAUTH_statd,
	RPCAUTH_nfsd4_cb,
968
	RPCAUTH_cache,
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	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,
	},
997 998 999 1000
	[RPCAUTH_cache] = {
		.name = "cache",
		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
	},
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};

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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;
1018
	sb->s_root = root = d_alloc_root(inode);
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	if (!root) {
		iput(inode);
		return -ENOMEM;
	}
1023
	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1024
		return -ENOMEM;
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	return 0;
}

1028
static int
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rpc_get_sb(struct file_system_type *fs_type,
1030
		int flags, const char *dev_name, void *data, struct vfsmount *mnt)
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1031
{
1032
	return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
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}

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
1043
init_once(void *foo)
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{
	struct rpc_inode *rpci = (struct rpc_inode *) foo;

C
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	inode_init_once(&rpci->vfs_inode);
	rpci->private = NULL;
	rpci->nreaders = 0;
	rpci->nwriters = 0;
	INIT_LIST_HEAD(&rpci->in_upcall);
1052
	INIT_LIST_HEAD(&rpci->in_downcall);
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1053 1054 1055 1056 1057 1058
	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;
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}

int register_rpc_pipefs(void)
{
1063 1064
	int err;

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	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1066 1067 1068
				sizeof(struct rpc_inode),
				0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
						SLAB_MEM_SPREAD),
1069
				init_once);
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	if (!rpc_inode_cachep)
		return -ENOMEM;
1072 1073 1074 1075 1076 1077
	err = register_filesystem(&rpc_pipe_fs_type);
	if (err) {
		kmem_cache_destroy(rpc_inode_cachep);
		return err;
	}

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	return 0;
}

void unregister_rpc_pipefs(void)
{
1083
	kmem_cache_destroy(rpc_inode_cachep);
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	unregister_filesystem(&rpc_pipe_fs_type);
}