rpc_pipe.c 24.5 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_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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};

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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);
	if (dentry->d_inode == NULL)
		return dentry;
	dput(dentry);
	return ERR_PTR(-EEXIST);
}

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/*
 * FIXME: This probably has races.
 */
599 600 601
static void __rpc_depopulate(struct dentry *parent,
			     const struct rpc_filelist *files,
			     int start, int eof)
L
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{
	struct inode *dir = parent->d_inode;
604 605 606
	struct dentry *dentry;
	struct qstr name;
	int i;
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608 609 610 611 612 613 614
	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;
616 617 618 619 620 621 622
		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;
624 625 626 627 628
			case S_IFDIR:
				__rpc_rmdir(dir, dentry);
		}
next:
		dput(dentry);
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	}
630 631 632 633 634 635 636 637 638 639
}

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);
640
	mutex_unlock(&dir->i_mutex);
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}

643 644 645 646
static int rpc_populate(struct dentry *parent,
			const struct rpc_filelist *files,
			int start, int eof,
			void *private)
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{
648
	struct inode *dir = parent->d_inode;
L
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	struct dentry *dentry;
650
	int i, err;
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652
	mutex_lock(&dir->i_mutex);
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	for (i = start; i < eof; i++) {
654 655 656 657 658 659 660 661
		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;
663 664 665 666 667 668 669 670 671 672 673 674 675 676
		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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677
		}
678 679
		if (err != 0)
			goto out_bad;
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680
	}
681
	mutex_unlock(&dir->i_mutex);
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	return 0;
out_bad:
684
	__rpc_depopulate(parent, files, start, eof);
685
	mutex_unlock(&dir->i_mutex);
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	printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
687
			__FILE__, __func__, parent->d_name.name);
688
	return err;
689
}
L
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691 692 693
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)
694 695
{
	struct dentry *dentry;
696
	struct inode *dir = parent->d_inode;
697 698
	int error;

699 700
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
	dentry = __rpc_lookup_create_exclusive(parent, name);
701
	if (IS_ERR(dentry))
702 703
		goto out;
	error = __rpc_mkdir(dir, dentry, mode, NULL, private);
704 705
	if (error != 0)
		goto out_err;
706 707 708 709 710
	if (populate != NULL) {
		error = populate(dentry, args_populate);
		if (error)
			goto err_rmdir;
	}
711
out:
712
	mutex_unlock(&dir->i_mutex);
713
	return dentry;
714
err_rmdir:
715
	__rpc_rmdir(dir, dentry);
716
out_err:
717 718
	dentry = ERR_PTR(error);
	goto out;
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}

721 722
static int rpc_rmdir_depopulate(struct dentry *dentry,
		void (*depopulate)(struct dentry *))
L
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{
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724
	struct dentry *parent;
725 726
	struct inode *dir;
	int error;
727

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	parent = dget_parent(dentry);
	dir = parent->d_inode;
730
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
731 732
	if (depopulate != NULL)
		depopulate(dentry);
733
	error = __rpc_rmdir(dir, dentry);
734
	mutex_unlock(&dir->i_mutex);
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	dput(parent);
736
	return error;
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}

739 740 741 742 743 744
/**
 * 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,
745
 *	release_pipe, open_pipe, and destroy_msg.
746
 * @flags: rpc_inode flags
747 748 749 750 751 752 753 754 755 756 757 758
 *
 * 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.
 */
759 760 761
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;
764
	struct inode *dir = parent->d_inode;
765
	umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
766
	struct qstr q;
767
	int err;
768 769 770 771 772

	if (ops->upcall == NULL)
		umode &= ~S_IRUGO;
	if (ops->downcall == NULL)
		umode &= ~S_IWUGO;
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774 775 776 777 778 779
	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))
781
		goto out;
782
	if (dentry->d_inode) {
783
		struct rpc_inode *rpci = RPC_I(dentry->d_inode);
784 785 786 787
		if (rpci->private != private ||
				rpci->ops != ops ||
				rpci->flags != flags) {
			dput (dentry);
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			err = -EBUSY;
			goto out_err;
790
		}
791
		rpci->nkern_readwriters++;
792 793
		goto out;
	}
794 795

	err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
T
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			   private, ops, flags);
797 798
	if (err)
		goto out_err;
799
out:
800
	mutex_unlock(&dir->i_mutex);
801
	return dentry;
802 803
out_err:
	dentry = ERR_PTR(err);
804
	printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
805
			__FILE__, __func__, parent->d_name.name, name,
806
			err);
807
	goto out;
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808
}
809
EXPORT_SYMBOL_GPL(rpc_mkpipe);
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811 812 813 814 815 816 817 818
/**
 * 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.
 */
819
int
820
rpc_unlink(struct dentry *dentry)
L
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821
{
822
	struct dentry *parent;
823
	struct inode *dir;
824
	int error = 0;
L
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826 827
	parent = dget_parent(dentry);
	dir = parent->d_inode;
828
	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
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	error = __rpc_rmpipe(dir, dentry);
830
	mutex_unlock(&dir->i_mutex);
831
	dput(parent);
832
	return error;
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}
834
EXPORT_SYMBOL_GPL(rpc_unlink);
L
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836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860
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);
}

861 862 863 864 865 866 867 868 869 870
/**
 * 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().
 */
871
struct dentry *rpc_create_client_dir(struct dentry *dentry,
872 873 874 875 876 877 878 879 880 881 882 883
				   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)
884
{
885
	return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
886 887
}

888 889 890 891
static const struct rpc_filelist cache_pipefs_files[3] = {
	[0] = {
		.name = "channel",
		.i_fop = &cache_file_operations_pipefs,
892
		.mode = S_IFREG|S_IRUSR|S_IWUSR,
893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929
	},
	[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
 */
static struct super_operations s_ops = {
	.alloc_inode	= rpc_alloc_inode,
	.destroy_inode	= rpc_destroy_inode,
	.statfs		= simple_statfs,
};

#define RPCAUTH_GSSMAGIC 0x67596969

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941 942 943 944 945 946 947 948 949 950
/*
 * We have a single directory with 1 node in it.
 */
enum {
	RPCAUTH_lockd,
	RPCAUTH_mount,
	RPCAUTH_nfs,
	RPCAUTH_portmap,
	RPCAUTH_statd,
	RPCAUTH_nfsd4_cb,
951
	RPCAUTH_cache,
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952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
	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,
	},
980 981 982 983
	[RPCAUTH_cache] = {
		.name = "cache",
		.mode = S_IFDIR | S_IRUGO | S_IXUGO,
	},
T
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};

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986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005
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;
	}
1006
	if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
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		goto out;
	sb->s_root = root;
	return 0;
out:
	d_genocide(root);
	dput(root);
	return -ENOMEM;
}

1016
static int
L
Linus Torvalds 已提交
1017
rpc_get_sb(struct file_system_type *fs_type,
1018
		int flags, const char *dev_name, void *data, struct vfsmount *mnt)
L
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1019
{
1020
	return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
L
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1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
}

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
1031
init_once(void *foo)
L
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1032 1033 1034
{
	struct rpc_inode *rpci = (struct rpc_inode *) foo;

C
Christoph Lameter 已提交
1035 1036 1037 1038 1039
	inode_init_once(&rpci->vfs_inode);
	rpci->private = NULL;
	rpci->nreaders = 0;
	rpci->nwriters = 0;
	INIT_LIST_HEAD(&rpci->in_upcall);
1040
	INIT_LIST_HEAD(&rpci->in_downcall);
C
Christoph Lameter 已提交
1041 1042 1043 1044 1045 1046
	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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1047 1048 1049 1050
}

int register_rpc_pipefs(void)
{
1051 1052
	int err;

L
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1053
	rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1054 1055 1056
				sizeof(struct rpc_inode),
				0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
						SLAB_MEM_SPREAD),
1057
				init_once);
L
Linus Torvalds 已提交
1058 1059
	if (!rpc_inode_cachep)
		return -ENOMEM;
1060 1061 1062 1063 1064 1065
	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)
{
1071
	kmem_cache_destroy(rpc_inode_cachep);
L
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1072 1073
	unregister_filesystem(&rpc_pipe_fs_type);
}