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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static struct vfsmount *rpc_mnt __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
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rpc_i_callback(struct rcu_head *head)
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{
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	struct inode *inode = container_of(head, struct inode, i_rcu);
	INIT_LIST_HEAD(&inode->i_dentry);
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	kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
}

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static void
rpc_destroy_inode(struct inode *inode)
{
	call_rcu(&inode->i_rcu, rpc_i_callback);
}

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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;
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	msg = filp->private_data;
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	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;
}

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

	switch (cmd) {
	case FIONREAD:
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		spin_lock(&inode->i_lock);
		if (rpci->ops == NULL) {
			spin_unlock(&inode->i_lock);
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			return -EPIPE;
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		}
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		len = rpci->pipelen;
		if (filp->private_data) {
			struct rpc_pipe_msg *msg;
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			msg = filp->private_data;
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			len += msg->len - msg->copied;
		}
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		spin_unlock(&inode->i_lock);
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		return put_user(len, (int __user *)arg);
	default:
		return -EINVAL;
	}
}

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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_mnt, &rpc_mount_count);
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	if (err != 0)
		return ERR_PTR(err);
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	return rpc_mnt;
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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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{
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	simple_release_fs(&rpc_mnt, &rpc_mount_count);
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}
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EXPORT_SYMBOL_GPL(rpc_put_mount);
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static int rpc_delete_dentry(const struct dentry *dentry)
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{
	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;
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	inode->i_ino = get_next_ino();
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	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);
}

580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604
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);
605 606
	if (IS_ERR(dentry))
		return dentry;
607 608 609 610 611 612
	if (dentry->d_inode == NULL)
		return dentry;
	dput(dentry);
	return ERR_PTR(-EEXIST);
}

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/*
 * FIXME: This probably has races.
 */
616 617 618
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;
621 622 623
	struct dentry *dentry;
	struct qstr name;
	int i;
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625 626 627 628 629 630 631
	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)
T
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			continue;
633 634 635 636 637 638 639
		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;
641 642 643 644 645
			case S_IFDIR:
				__rpc_rmdir(dir, dentry);
		}
next:
		dput(dentry);
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	}
647 648 649 650 651 652 653 654 655 656
}

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);
657
	mutex_unlock(&dir->i_mutex);
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}

660 661 662 663
static int rpc_populate(struct dentry *parent,
			const struct rpc_filelist *files,
			int start, int eof,
			void *private)
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{
665
	struct inode *dir = parent->d_inode;
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	struct dentry *dentry;
667
	int i, err;
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669
	mutex_lock(&dir->i_mutex);
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	for (i = start; i < eof; i++) {
671 672 673 674 675 676 677 678
		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;
680 681 682 683 684 685 686 687 688 689 690 691 692 693
		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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		}
695 696
		if (err != 0)
			goto out_bad;
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	}
698
	mutex_unlock(&dir->i_mutex);
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	return 0;
out_bad:
701
	__rpc_depopulate(parent, files, start, eof);
702
	mutex_unlock(&dir->i_mutex);
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	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
704
			__FILE__, __func__, parent->d_name.name);
705
	return err;
706
}
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708 709 710
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)
711 712
{
	struct dentry *dentry;
713
	struct inode *dir = parent->d_inode;
714 715
	int error;

716 717
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
	dentry = __rpc_lookup_create_exclusive(parent, name);
718
	if (IS_ERR(dentry))
719 720
		goto out;
	error = __rpc_mkdir(dir, dentry, mode, NULL, private);
721 722
	if (error != 0)
		goto out_err;
723 724 725 726 727
	if (populate != NULL) {
		error = populate(dentry, args_populate);
		if (error)
			goto err_rmdir;
	}
728
out:
729
	mutex_unlock(&dir->i_mutex);
730
	return dentry;
731
err_rmdir:
732
	__rpc_rmdir(dir, dentry);
733
out_err:
734 735
	dentry = ERR_PTR(error);
	goto out;
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}

738 739
static int rpc_rmdir_depopulate(struct dentry *dentry,
		void (*depopulate)(struct dentry *))
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{
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	struct dentry *parent;
742 743
	struct inode *dir;
	int error;
744

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	parent = dget_parent(dentry);
	dir = parent->d_inode;
747
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
748 749
	if (depopulate != NULL)
		depopulate(dentry);
750
	error = __rpc_rmdir(dir, dentry);
751
	mutex_unlock(&dir->i_mutex);
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	dput(parent);
753
	return error;
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}

756 757 758 759 760 761
/**
 * 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,
762
 *	release_pipe, open_pipe, and destroy_msg.
763
 * @flags: rpc_inode flags
764 765 766 767 768 769 770 771 772 773 774 775
 *
 * 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;
781
	struct inode *dir = parent->d_inode;
782
	umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
783
	struct qstr q;
784
	int err;
785 786 787 788 789

	if (ops->upcall == NULL)
		umode &= ~S_IRUGO;
	if (ops->downcall == NULL)
		umode &= ~S_IWUGO;
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791 792 793 794 795 796
	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))
798
		goto out;
799
	if (dentry->d_inode) {
800
		struct rpc_inode *rpci = RPC_I(dentry->d_inode);
801 802 803 804
		if (rpci->private != private ||
				rpci->ops != ops ||
				rpci->flags != flags) {
			dput (dentry);
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			err = -EBUSY;
			goto out_err;
807
		}
808
		rpci->nkern_readwriters++;
809 810
		goto out;
	}
811 812

	err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
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			   private, ops, flags);
814 815
	if (err)
		goto out_err;
816
out:
817
	mutex_unlock(&dir->i_mutex);
818
	return dentry;
819 820
out_err:
	dentry = ERR_PTR(err);
821
	printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
822
			__FILE__, __func__, parent->d_name.name, name,
823
			err);
824
	goto out;
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}
826
EXPORT_SYMBOL_GPL(rpc_mkpipe);
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828 829 830 831 832 833 834 835
/**
 * 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.
 */
836
int
837
rpc_unlink(struct dentry *dentry)
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{
839
	struct dentry *parent;
840
	struct inode *dir;
841
	int error = 0;
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843 844
	parent = dget_parent(dentry);
	dir = parent->d_inode;
845
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
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	error = __rpc_rmpipe(dir, dentry);
847
	mutex_unlock(&dir->i_mutex);
848
	dput(parent);
849
	return error;
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}
851
EXPORT_SYMBOL_GPL(rpc_unlink);
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853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877
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);
}

878 879
/**
 * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
880 881
 * @dentry: dentry from the rpc_pipefs root to the new directory
 * @name: &struct qstr for the name
882 883 884 885 886 887 888
 * @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().
 */
889
struct dentry *rpc_create_client_dir(struct dentry *dentry,
890 891 892 893 894 895 896 897 898 899 900 901
				   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)
902
{
903
	return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
904 905
}

906 907 908 909
static const struct rpc_filelist cache_pipefs_files[3] = {
	[0] = {
		.name = "channel",
		.i_fop = &cache_file_operations_pipefs,
910
		.mode = S_IFREG|S_IRUSR|S_IWUSR,
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947
	},
	[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
 */
951
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,
969
	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,
	},
998 999 1000 1001
	[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;
1019
	sb->s_root = root = d_alloc_root(inode);
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	if (!root) {
		iput(inode);
		return -ENOMEM;
	}
1024
	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1025
		return -ENOMEM;
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	return 0;
}

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static struct dentry *
rpc_mount(struct file_system_type *fs_type,
		int flags, const char *dev_name, void *data)
L
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1032
{
A
Al Viro 已提交
1033
	return mount_single(fs_type, flags, data, rpc_fill_super);
L
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}

static struct file_system_type rpc_pipe_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "rpc_pipefs",
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1039
	.mount		= rpc_mount,
L
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1040 1041 1042 1043
	.kill_sb	= kill_litter_super,
};

static void
1044
init_once(void *foo)
L
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1045 1046 1047
{
	struct rpc_inode *rpci = (struct rpc_inode *) foo;

C
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1048 1049 1050 1051 1052
	inode_init_once(&rpci->vfs_inode);
	rpci->private = NULL;
	rpci->nreaders = 0;
	rpci->nwriters = 0;
	INIT_LIST_HEAD(&rpci->in_upcall);
1053
	INIT_LIST_HEAD(&rpci->in_downcall);
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Christoph Lameter 已提交
1054 1055 1056 1057 1058 1059
	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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1060 1061 1062 1063
}

int register_rpc_pipefs(void)
{
1064 1065
	int err;

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	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1067 1068 1069
				sizeof(struct rpc_inode),
				0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
						SLAB_MEM_SPREAD),
1070
				init_once);
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	if (!rpc_inode_cachep)
		return -ENOMEM;
1073 1074 1075 1076 1077 1078
	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)
{
1084
	kmem_cache_destroy(rpc_inode_cachep);
L
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1085 1086
	unregister_filesystem(&rpc_pipe_fs_type);
}