rpc_pipe.c 23.9 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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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(&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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/**
 * rpc_queue_upcall
 * @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(&msg->list);
		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);
		list_del(&msg->list);
		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
rpc_pipe_ioctl(struct inode *ino, struct file *filp,
		unsigned int cmd, unsigned long arg)
{
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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 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,
	.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);
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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)
{
	struct rpc_clnt *clnt;
	int ret = single_open(file, rpc_show_info, NULL);

	if (!ret) {
		struct seq_file *m = file->private_data;
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		mutex_lock(&inode->i_mutex);
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		clnt = RPC_I(inode)->private;
		if (clnt) {
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			kref_get(&clnt->cl_kref);
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			m->private = clnt;
		} else {
			single_release(inode, file);
			ret = -EINVAL;
		}
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		mutex_unlock(&inode->i_mutex);
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	}
	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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};

enum {
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	RPCAUTH_info,
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	RPCAUTH_EOF
};

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static const struct rpc_filelist authfiles[] = {
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	[RPCAUTH_info] = {
		.name = "info",
		.i_fop = &rpc_info_operations,
		.mode = S_IFREG | S_IRUSR,
	},
};

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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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void rpc_put_mount(void)
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{
	simple_release_fs(&rpc_mount, &rpc_mount_count);
}

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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 int __rpc_lookup_path(const char *pathname, unsigned flags,
			     struct nameidata *nd)
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{
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	struct vfsmount *mnt;

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	if (pathname[0] == '\0')
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		return -ENOENT;
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	mnt = rpc_get_mount();
	if (IS_ERR(mnt)) {
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		printk(KERN_WARNING "%s: %s failed to mount "
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			       "pseudofilesystem \n", __FILE__, __func__);
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		return PTR_ERR(mnt);
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	}

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	if (vfs_path_lookup(mnt->mnt_root, mnt, pathname, flags, nd)) {
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		printk(KERN_WARNING "%s: %s failed to find path %s\n",
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				__FILE__, __func__, pathname);
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		rpc_put_mount();
		return -ENOENT;
	}
	return 0;
}

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static int rpc_lookup_parent(const char *pathname, struct nameidata *nd)
{
	return __rpc_lookup_path(pathname, LOOKUP_PARENT, nd);
}

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static void
rpc_release_path(struct nameidata *nd)
{
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	path_put(&nd->path);
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	rpc_put_mount();
}

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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);
}

611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641
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);
	if (dentry->d_inode == NULL)
		return dentry;
	dput(dentry);
	return ERR_PTR(-EEXIST);
}

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/*
 * FIXME: This probably has races.
 */
645 646 647
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;
650 651 652
	struct dentry *dentry;
	struct qstr name;
	int i;
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654 655 656 657 658 659 660
	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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661
			continue;
662 663 664 665 666 667 668
		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;
670 671 672 673 674
			case S_IFDIR:
				__rpc_rmdir(dir, dentry);
		}
next:
		dput(dentry);
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	}
676 677 678 679 680 681 682 683 684 685
}

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);
686
	mutex_unlock(&dir->i_mutex);
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}

689 690 691 692
static int rpc_populate(struct dentry *parent,
			const struct rpc_filelist *files,
			int start, int eof,
			void *private)
L
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693
{
694
	struct inode *dir = parent->d_inode;
L
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695
	struct dentry *dentry;
696
	int i, err;
L
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698
	mutex_lock(&dir->i_mutex);
L
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699
	for (i = start; i < eof; i++) {
700 701 702 703 704 705 706 707
		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;
709 710 711 712 713 714 715 716 717 718 719 720 721 722
		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);
L
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723
		}
724 725
		if (err != 0)
			goto out_bad;
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726
	}
727
	mutex_unlock(&dir->i_mutex);
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	return 0;
out_bad:
730
	__rpc_depopulate(parent, files, start, eof);
731
	mutex_unlock(&dir->i_mutex);
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	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
733
			__FILE__, __func__, parent->d_name.name);
734
	return err;
735
}
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737 738
struct dentry *rpc_mkdir_populate(struct dentry *parent,
		struct qstr *name, umode_t mode, void *private)
739 740
{
	struct dentry *dentry;
741
	struct inode *dir = parent->d_inode;
742 743
	int error;

744 745
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
	dentry = __rpc_lookup_create_exclusive(parent, name);
746
	if (IS_ERR(dentry))
747 748
		goto out;
	error = __rpc_mkdir(dir, dentry, mode, NULL, private);
749 750
	if (error != 0)
		goto out_err;
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	error = rpc_populate(dentry, authfiles,
752
			RPCAUTH_info, RPCAUTH_EOF, private);
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	if (error)
754
		goto err_rmdir;
755
out:
756
	mutex_unlock(&dir->i_mutex);
757
	return dentry;
758
err_rmdir:
759
	__rpc_rmdir(dir, dentry);
760
out_err:
761 762
	dentry = ERR_PTR(error);
	goto out;
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}

765
/**
766
 * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
767 768
 * @dentry: directory to remove
 */
769
int rpc_remove_client_dir(struct dentry *dentry)
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770
{
T
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771
	struct dentry *parent;
772 773
	struct inode *dir;
	int error;
774

T
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775 776
	parent = dget_parent(dentry);
	dir = parent->d_inode;
777
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
778
	rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
779
	error = __rpc_rmdir(dir, dentry);
780
	mutex_unlock(&dir->i_mutex);
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	dput(parent);
782
	return error;
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}

785 786 787 788 789 790
/**
 * 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,
791
 *	release_pipe, open_pipe, and destroy_msg.
792
 * @flags: rpc_inode flags
793 794 795 796 797 798 799 800 801 802 803 804
 *
 * 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.
 */
805 806 807
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;
810
	struct inode *dir = parent->d_inode;
811
	umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
812
	struct qstr q;
813
	int err;
814 815 816 817 818

	if (ops->upcall == NULL)
		umode &= ~S_IRUGO;
	if (ops->downcall == NULL)
		umode &= ~S_IWUGO;
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820 821 822 823 824 825
	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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826
	if (IS_ERR(dentry))
827
		goto out;
828
	if (dentry->d_inode) {
829
		struct rpc_inode *rpci = RPC_I(dentry->d_inode);
830 831 832 833
		if (rpci->private != private ||
				rpci->ops != ops ||
				rpci->flags != flags) {
			dput (dentry);
T
Trond Myklebust 已提交
834 835
			err = -EBUSY;
			goto out_err;
836
		}
837
		rpci->nkern_readwriters++;
838 839
		goto out;
	}
840 841

	err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
T
Trond Myklebust 已提交
842
			   private, ops, flags);
843 844
	if (err)
		goto out_err;
845
out:
846
	mutex_unlock(&dir->i_mutex);
847
	return dentry;
848 849
out_err:
	dentry = ERR_PTR(err);
850
	printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
851
			__FILE__, __func__, parent->d_name.name, name,
852
			err);
853
	goto out;
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854
}
855
EXPORT_SYMBOL_GPL(rpc_mkpipe);
L
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856

857 858 859 860 861 862 863 864
/**
 * 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.
 */
865
int
866
rpc_unlink(struct dentry *dentry)
L
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867
{
868
	struct dentry *parent;
869
	struct inode *dir;
870
	int error = 0;
L
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871

872 873
	parent = dget_parent(dentry);
	dir = parent->d_inode;
874
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
T
Trond Myklebust 已提交
875
	error = __rpc_rmpipe(dir, dentry);
876
	mutex_unlock(&dir->i_mutex);
877
	dput(parent);
878
	return error;
L
Linus Torvalds 已提交
879
}
880
EXPORT_SYMBOL_GPL(rpc_unlink);
L
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882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914
/**
 * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 * @path: path from the rpc_pipefs root to the new directory
 * @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(const char *path,
				     struct rpc_clnt *rpc_client)
{
	struct nameidata nd;
	struct dentry *ret;
	struct inode *dir;

	ret = ERR_PTR(rpc_lookup_parent(path, &nd));
	if (IS_ERR(ret))
		goto out_err;
	dir = nd.path.dentry->d_inode;

	ret = rpc_mkdir_populate(nd.path.dentry, &nd.last,
			S_IRUGO | S_IXUGO, rpc_client);
	rpc_release_path(&nd);
	if (!IS_ERR(ret))
		return ret;
out_err:
	printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %ld)\n",
			__FILE__, __func__, path, PTR_ERR(ret));
	return ret;
}

L
Linus Torvalds 已提交
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/*
 * populate the filesystem
 */
static struct super_operations s_ops = {
	.alloc_inode	= rpc_alloc_inode,
	.destroy_inode	= rpc_destroy_inode,
	.statfs		= simple_statfs,
};

#define RPCAUTH_GSSMAGIC 0x67596969

T
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926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965
/*
 * 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_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,
	},
};

L
Linus Torvalds 已提交
966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985
static int
rpc_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *inode;
	struct dentry *root;

	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = RPCAUTH_GSSMAGIC;
	sb->s_op = &s_ops;
	sb->s_time_gran = 1;

	inode = rpc_get_inode(sb, S_IFDIR | 0755);
	if (!inode)
		return -ENOMEM;
	root = d_alloc_root(inode);
	if (!root) {
		iput(inode);
		return -ENOMEM;
	}
986
	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
L
Linus Torvalds 已提交
987 988 989 990 991 992 993 994 995
		goto out;
	sb->s_root = root;
	return 0;
out:
	d_genocide(root);
	dput(root);
	return -ENOMEM;
}

996
static int
L
Linus Torvalds 已提交
997
rpc_get_sb(struct file_system_type *fs_type,
998
		int flags, const char *dev_name, void *data, struct vfsmount *mnt)
L
Linus Torvalds 已提交
999
{
1000
	return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
L
Linus Torvalds 已提交
1001 1002 1003 1004 1005 1006 1007 1008 1009 1010
}

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
1011
init_once(void *foo)
L
Linus Torvalds 已提交
1012 1013 1014
{
	struct rpc_inode *rpci = (struct rpc_inode *) foo;

C
Christoph Lameter 已提交
1015 1016 1017 1018 1019
	inode_init_once(&rpci->vfs_inode);
	rpci->private = NULL;
	rpci->nreaders = 0;
	rpci->nwriters = 0;
	INIT_LIST_HEAD(&rpci->in_upcall);
1020
	INIT_LIST_HEAD(&rpci->in_downcall);
C
Christoph Lameter 已提交
1021 1022 1023 1024 1025 1026
	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;
L
Linus Torvalds 已提交
1027 1028 1029 1030
}

int register_rpc_pipefs(void)
{
1031 1032
	int err;

L
Linus Torvalds 已提交
1033
	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1034 1035 1036
				sizeof(struct rpc_inode),
				0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
						SLAB_MEM_SPREAD),
1037
				init_once);
L
Linus Torvalds 已提交
1038 1039
	if (!rpc_inode_cachep)
		return -ENOMEM;
1040 1041 1042 1043 1044 1045
	err = register_filesystem(&rpc_pipe_fs_type);
	if (err) {
		kmem_cache_destroy(rpc_inode_cachep);
		return err;
	}

L
Linus Torvalds 已提交
1046 1047 1048 1049 1050
	return 0;
}

void unregister_rpc_pipefs(void)
{
1051
	kmem_cache_destroy(rpc_inode_cachep);
L
Linus Torvalds 已提交
1052 1053
	unregister_filesystem(&rpc_pipe_fs_type);
}