[linux-2.6-block.git] / fs / autofs4 / waitq.c

/* -*- c -*- --------------------------------------------------------------- *
 *
 * linux/fs/autofs/waitq.c
 *
 *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
 *  Copyright 2001-2006 Ian Kent <raven@themaw.net>
 *
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
 *
 * ------------------------------------------------------------------------- */

#include <linux/slab.h>
#include <linux/time.h>
#include <linux/signal.h>
#include <linux/file.h>
#include "autofs_i.h"

/* We make this a static variable rather than a part of the superblock; it
   is better if we don't reassign numbers easily even across filesystems */
static autofs_wqt_t autofs4_next_wait_queue = 1;

/* These are the signals we allow interrupting a pending mount */
#define SHUTDOWN_SIGS	(sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))

void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
{
	struct autofs_wait_queue *wq, *nwq;

	mutex_lock(&sbi->wq_mutex);
	if (sbi->catatonic) {
		mutex_unlock(&sbi->wq_mutex);
		return;
	}

	DPRINTK("entering catatonic mode");

	sbi->catatonic = 1;
	wq = sbi->queues;
	sbi->queues = NULL;	/* Erase all wait queues */
	while (wq) {
		nwq = wq->next;
		wq->status = -ENOENT; /* Magic is gone - report failure */
		kfree(wq->name.name);
		wq->name.name = NULL;
		wq->wait_ctr--;
		wake_up_interruptible(&wq->queue);
		wq = nwq;
	}
	fput(sbi->pipe);	/* Close the pipe */
	sbi->pipe = NULL;
	sbi->pipefd = -1;
	mutex_unlock(&sbi->wq_mutex);
}

static int autofs4_write(struct autofs_sb_info *sbi,
			 struct file *file, const void *addr, int bytes)
{
	unsigned long sigpipe, flags;
	mm_segment_t fs;
	const char *data = (const char *)addr;
	ssize_t wr = 0;

	sigpipe = sigismember(&current->pending.signal, SIGPIPE);

	/* Save pointer to user space and point back to kernel space */
	fs = get_fs();
	set_fs(KERNEL_DS);

	mutex_lock(&sbi->pipe_mutex);
	while (bytes &&
	       (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
		data += wr;
		bytes -= wr;
	}
	mutex_unlock(&sbi->pipe_mutex);

	set_fs(fs);

	/* Keep the currently executing process from receiving a
	   SIGPIPE unless it was already supposed to get one */
	if (wr == -EPIPE && !sigpipe) {
		spin_lock_irqsave(&current->sighand->siglock, flags);
		sigdelset(&current->pending.signal, SIGPIPE);
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, flags);
	}

	return (bytes > 0);
}
	
static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
				 struct autofs_wait_queue *wq,
				 int type)
{
	union {
		struct autofs_packet_hdr hdr;
		union autofs_packet_union v4_pkt;
		union autofs_v5_packet_union v5_pkt;
	} pkt;
	struct file *pipe = NULL;
	size_t pktsz;

	DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
		(unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);

	memset(&pkt,0,sizeof pkt); /* For security reasons */

	pkt.hdr.proto_version = sbi->version;
	pkt.hdr.type = type;

	switch (type) {
	/* Kernel protocol v4 missing and expire packets */
	case autofs_ptype_missing:
	{
		struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;

		pktsz = sizeof(*mp);

		mp->wait_queue_token = wq->wait_queue_token;
		mp->len = wq->name.len;
		memcpy(mp->name, wq->name.name, wq->name.len);
		mp->name[wq->name.len] = '\0';
		break;
	}
	case autofs_ptype_expire_multi:
	{
		struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;

		pktsz = sizeof(*ep);

		ep->wait_queue_token = wq->wait_queue_token;
		ep->len = wq->name.len;
		memcpy(ep->name, wq->name.name, wq->name.len);
		ep->name[wq->name.len] = '\0';
		break;
	}
	/*
	 * Kernel protocol v5 packet for handling indirect and direct
	 * mount missing and expire requests
	 */
	case autofs_ptype_missing_indirect:
	case autofs_ptype_expire_indirect:
	case autofs_ptype_missing_direct:
	case autofs_ptype_expire_direct:
	{
		struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
		struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;

		pktsz = sizeof(*packet);

		packet->wait_queue_token = wq->wait_queue_token;
		packet->len = wq->name.len;
		memcpy(packet->name, wq->name.name, wq->name.len);
		packet->name[wq->name.len] = '\0';
		packet->dev = wq->dev;
		packet->ino = wq->ino;
		packet->uid = from_kuid_munged(user_ns, wq->uid);
		packet->gid = from_kgid_munged(user_ns, wq->gid);
		packet->pid = wq->pid;
		packet->tgid = wq->tgid;
		break;
	}
	default:
		printk("autofs4_notify_daemon: bad type %d!\n", type);
		mutex_unlock(&sbi->wq_mutex);
		return;
	}

	pipe = get_file(sbi->pipe);

	mutex_unlock(&sbi->wq_mutex);

	if (autofs4_write(sbi, pipe, &pkt, pktsz))
		autofs4_catatonic_mode(sbi);
	fput(pipe);
}

static int autofs4_getpath(struct autofs_sb_info *sbi,
			   struct dentry *dentry, char **name)
{
	struct dentry *root = sbi->sb->s_root;
	struct dentry *tmp;
	char *buf;
	char *p;
	int len;
	unsigned seq;

rename_retry:
	buf = *name;
	len = 0;

	seq = read_seqbegin(&rename_lock);
	rcu_read_lock();
	spin_lock(&sbi->fs_lock);
	for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
		len += tmp->d_name.len + 1;

	if (!len || --len > NAME_MAX) {
		spin_unlock(&sbi->fs_lock);
		rcu_read_unlock();
		if (read_seqretry(&rename_lock, seq))
			goto rename_retry;
		return 0;
	}

	*(buf + len) = '\0';
	p = buf + len - dentry->d_name.len;
	strncpy(p, dentry->d_name.name, dentry->d_name.len);

	for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
		*(--p) = '/';
		p -= tmp->d_name.len;
		strncpy(p, tmp->d_name.name, tmp->d_name.len);
	}
	spin_unlock(&sbi->fs_lock);
	rcu_read_unlock();
	if (read_seqretry(&rename_lock, seq))
		goto rename_retry;

	return len;
}

static struct autofs_wait_queue *
autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr)
{
	struct autofs_wait_queue *wq;

	for (wq = sbi->queues; wq; wq = wq->next) {
		if (wq->name.hash == qstr->hash &&
		    wq->name.len == qstr->len &&
		    wq->name.name &&
			 !memcmp(wq->name.name, qstr->name, qstr->len))
			break;
	}
	return wq;
}

/*
 * Check if we have a valid request.
 * Returns
 * 1 if the request should continue.
 *   In this case we can return an autofs_wait_queue entry if one is
 *   found or NULL to idicate a new wait needs to be created.
 * 0 or a negative errno if the request shouldn't continue.
 */
static int validate_request(struct autofs_wait_queue **wait,
			    struct autofs_sb_info *sbi,
			    struct qstr *qstr,
			    struct dentry*dentry, enum autofs_notify notify)
{
	struct autofs_wait_queue *wq;
	struct autofs_info *ino;

	if (sbi->catatonic)
		return -ENOENT;

	/* Wait in progress, continue; */
	wq = autofs4_find_wait(sbi, qstr);
	if (wq) {
		*wait = wq;
		return 1;
	}

	*wait = NULL;

	/* If we don't yet have any info this is a new request */
	ino = autofs4_dentry_ino(dentry);
	if (!ino)
		return 1;

	/*
	 * If we've been asked to wait on an existing expire (NFY_NONE)
	 * but there is no wait in the queue ...
	 */
	if (notify == NFY_NONE) {
		/*
		 * Either we've betean the pending expire to post it's
		 * wait or it finished while we waited on the mutex.
		 * So we need to wait till either, the wait appears
		 * or the expire finishes.
		 */

		while (ino->flags & AUTOFS_INF_EXPIRING) {
			mutex_unlock(&sbi->wq_mutex);
			schedule_timeout_interruptible(HZ/10);
			if (mutex_lock_interruptible(&sbi->wq_mutex))
				return -EINTR;

			if (sbi->catatonic)
				return -ENOENT;

			wq = autofs4_find_wait(sbi, qstr);
			if (wq) {
				*wait = wq;
				return 1;
			}
		}

		/*
		 * Not ideal but the status has already gone. Of the two
		 * cases where we wait on NFY_NONE neither depend on the
		 * return status of the wait.
		 */
		return 0;
	}

	/*
	 * If we've been asked to trigger a mount and the request
	 * completed while we waited on the mutex ...
	 */
	if (notify == NFY_MOUNT) {
		struct dentry *new = NULL;
		int valid = 1;

		/*
		 * If the dentry was successfully mounted while we slept
		 * on the wait queue mutex we can return success. If it
		 * isn't mounted (doesn't have submounts for the case of
		 * a multi-mount with no mount at it's base) we can
		 * continue on and create a new request.
		 */
		if (!IS_ROOT(dentry)) {
			if (dentry->d_inode && d_unhashed(dentry)) {
				struct dentry *parent = dentry->d_parent;
				new = d_lookup(parent, &dentry->d_name);
				if (new)
					dentry = new;
			}
		}
		if (have_submounts(dentry))
			valid = 0;

		if (new)
			dput(new);
		return valid;
	}

	return 1;
}

int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
		enum autofs_notify notify)
{
	struct autofs_wait_queue *wq;
	struct qstr qstr;
	char *name;
	int status, ret, type;
	pid_t pid;
	pid_t tgid;

	/* In catatonic mode, we don't wait for nobody */
	if (sbi->catatonic)
		return -ENOENT;

	/*
	 * Try translating pids to the namespace of the daemon.
	 *
	 * Zero means failure: we are in an unrelated pid namespace.
	 */
	pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
	tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
	if (pid == 0 || tgid == 0)
		return -ENOENT;

	if (!dentry->d_inode) {
		/*
		 * A wait for a negative dentry is invalid for certain
		 * cases. A direct or offset mount "always" has its mount
		 * point directory created and so the request dentry must
		 * be positive or the map key doesn't exist. The situation
		 * is very similar for indirect mounts except only dentrys
		 * in the root of the autofs file system may be negative.
		 */
		if (autofs_type_trigger(sbi->type))
			return -ENOENT;
		else if (!IS_ROOT(dentry->d_parent))
			return -ENOENT;
	}

	name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
	if (!name)
		return -ENOMEM;

	/* If this is a direct mount request create a dummy name */
	if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
		qstr.len = sprintf(name, "%p", dentry);
	else {
		qstr.len = autofs4_getpath(sbi, dentry, &name);
		if (!qstr.len) {
			kfree(name);
			return -ENOENT;
		}
	}
	qstr.name = name;
	qstr.hash = full_name_hash(name, qstr.len);

	if (mutex_lock_interruptible(&sbi->wq_mutex)) {
		kfree(qstr.name);
		return -EINTR;
	}

	ret = validate_request(&wq, sbi, &qstr, dentry, notify);
	if (ret <= 0) {
		if (ret != -EINTR)
			mutex_unlock(&sbi->wq_mutex);
		kfree(qstr.name);
		return ret;
	}

	if (!wq) {
		/* Create a new wait queue */
		wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
		if (!wq) {
			kfree(qstr.name);
			mutex_unlock(&sbi->wq_mutex);
			return -ENOMEM;
		}

		wq->wait_queue_token = autofs4_next_wait_queue;
		if (++autofs4_next_wait_queue == 0)
			autofs4_next_wait_queue = 1;
		wq->next = sbi->queues;
		sbi->queues = wq;
		init_waitqueue_head(&wq->queue);
		memcpy(&wq->name, &qstr, sizeof(struct qstr));
		wq->dev = autofs4_get_dev(sbi);
		wq->ino = autofs4_get_ino(sbi);
		wq->uid = current_uid();
		wq->gid = current_gid();
		wq->pid = pid;
		wq->tgid = tgid;
		wq->status = -EINTR; /* Status return if interrupted */
		wq->wait_ctr = 2;

		if (sbi->version < 5) {
			if (notify == NFY_MOUNT)
				type = autofs_ptype_missing;
			else
				type = autofs_ptype_expire_multi;
		} else {
			if (notify == NFY_MOUNT)
				type = autofs_type_trigger(sbi->type) ?
					autofs_ptype_missing_direct :
					 autofs_ptype_missing_indirect;
			else
				type = autofs_type_trigger(sbi->type) ?
					autofs_ptype_expire_direct :
					autofs_ptype_expire_indirect;
		}

		DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
			(unsigned long) wq->wait_queue_token, wq->name.len,
			wq->name.name, notify);

		/* autofs4_notify_daemon() may block; it will unlock ->wq_mutex */
		autofs4_notify_daemon(sbi, wq, type);
	} else {
		wq->wait_ctr++;
		DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
			(unsigned long) wq->wait_queue_token, wq->name.len,
			wq->name.name, notify);
		mutex_unlock(&sbi->wq_mutex);
		kfree(qstr.name);
	}

	/*
	 * wq->name.name is NULL iff the lock is already released
	 * or the mount has been made catatonic.
	 */
	if (wq->name.name) {
		/* Block all but "shutdown" signals while waiting */
		sigset_t oldset;
		unsigned long irqflags;

		spin_lock_irqsave(&current->sighand->siglock, irqflags);
		oldset = current->blocked;
		siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);

		wait_event_interruptible(wq->queue, wq->name.name == NULL);

		spin_lock_irqsave(&current->sighand->siglock, irqflags);
		current->blocked = oldset;
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
	} else {
		DPRINTK("skipped sleeping");
	}

	status = wq->status;

	/*
	 * For direct and offset mounts we need to track the requester's
	 * uid and gid in the dentry info struct. This is so it can be
	 * supplied, on request, by the misc device ioctl interface.
	 * This is needed during daemon resatart when reconnecting
	 * to existing, active, autofs mounts. The uid and gid (and
	 * related string values) may be used for macro substitution
	 * in autofs mount maps.
	 */
	if (!status) {
		struct autofs_info *ino;
		struct dentry *de = NULL;

		/* direct mount or browsable map */
		ino = autofs4_dentry_ino(dentry);
		if (!ino) {
			/* If not lookup actual dentry used */
			de = d_lookup(dentry->d_parent, &dentry->d_name);
			if (de)
				ino = autofs4_dentry_ino(de);
		}

		/* Set mount requester */
		if (ino) {
			spin_lock(&sbi->fs_lock);
			ino->uid = wq->uid;
			ino->gid = wq->gid;
			spin_unlock(&sbi->fs_lock);
		}

		if (de)
			dput(de);
	}

	/* Are we the last process to need status? */
	mutex_lock(&sbi->wq_mutex);
	if (!--wq->wait_ctr)
		kfree(wq);
	mutex_unlock(&sbi->wq_mutex);

	return status;
}


int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
{
	struct autofs_wait_queue *wq, **wql;

	mutex_lock(&sbi->wq_mutex);
	for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
		if (wq->wait_queue_token == wait_queue_token)
			break;
	}

	if (!wq) {
		mutex_unlock(&sbi->wq_mutex);
		return -EINVAL;
	}

	*wql = wq->next;	/* Unlink from chain */
	kfree(wq->name.name);
	wq->name.name = NULL;	/* Do not wait on this queue */
	wq->status = status;
	wake_up_interruptible(&wq->queue);
	if (!--wq->wait_ctr)
		kfree(wq);
	mutex_unlock(&sbi->wq_mutex);

	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/* -- c -- --------------------------------------------------------------- *
	2	*
	3	* linux/fs/autofs/waitq.c
	4	*
	5	* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
5c0a32fc	6	* Copyright 2001-2006 Ian Kent <raven@themaw.net>
1da177e4 LT	7	*
	8	* This file is part of the Linux kernel and is made available under
	9	* the terms of the GNU General Public License, version 2, or at your
	10	* option, any later version, incorporated herein by reference.
	11	*
	12	* ------------------------------------------------------------------------- */
	13
	14	#include <linux/slab.h>
	15	#include <linux/time.h>
	16	#include <linux/signal.h>
	17	#include <linux/file.h>
	18	#include "autofs_i.h"
	19
	20	/* We make this a static variable rather than a part of the superblock; it
	21	is better if we don't reassign numbers easily even across filesystems */
	22	static autofs_wqt_t autofs4_next_wait_queue = 1;
	23
	24	/* These are the signals we allow interrupting a pending mount */
	25	#define SHUTDOWN_SIGS (sigmask(SIGKILL) \| sigmask(SIGINT) \| sigmask(SIGQUIT))
	26
	27	void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
	28	{
	29	struct autofs_wait_queue wq, nwq;
	30
5a11d4d0 IK	31	mutex_lock(&sbi->wq_mutex);
	32	if (sbi->catatonic) {
	33	mutex_unlock(&sbi->wq_mutex);
	34	return;
	35	}
	36
1da177e4 LT	37	DPRINTK("entering catatonic mode");
	38
	39	sbi->catatonic = 1;
	40	wq = sbi->queues;
	41	sbi->queues = NULL; /* Erase all wait queues */
e77fbddf	42	while (wq) {
1da177e4 LT	43	nwq = wq->next;
1da177e4 LT	44	wq->status = -ENOENT; /* Magic is gone - report failure */
5140a8ce TG	45	kfree(wq->name.name);
5140a8ce TG	46	wq->name.name = NULL;
296f7bf7	47	wq->wait_ctr--;
1da177e4 LT	48	wake_up_interruptible(&wq->queue);
	49	wq = nwq;
	50	}
ba8df43c IK	51	fput(sbi->pipe); /* Close the pipe */
ba8df43c IK	52	sbi->pipe = NULL;
5a11d4d0 IK	53	sbi->pipefd = -1;
5a11d4d0 IK	54	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	55	}
1da177e4 LT	56
d668dc56 AV	57	static int autofs4_write(struct autofs_sb_info *sbi,
d668dc56 AV	58	struct file file, const void addr, int bytes)
1da177e4 LT	59	{
	60	unsigned long sigpipe, flags;
	61	mm_segment_t fs;
	62	const char data = (const char )addr;
	63	ssize_t wr = 0;
	64
1da177e4 LT	65	sigpipe = sigismember(&current->pending.signal, SIGPIPE);
	66
	67	/* Save pointer to user space and point back to kernel space */
	68	fs = get_fs();
	69	set_fs(KERNEL_DS);
	70
d668dc56	71	mutex_lock(&sbi->pipe_mutex);
1da177e4 LT	72	while (bytes &&
	73	(wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
	74	data += wr;
	75	bytes -= wr;
	76	}
8638094e	77	mutex_unlock(&sbi->pipe_mutex);
1da177e4 LT	78
	79	set_fs(fs);
	80
	81	/* Keep the currently executing process from receiving a
	82	SIGPIPE unless it was already supposed to get one */
	83	if (wr == -EPIPE && !sigpipe) {
	84	spin_lock_irqsave(&current->sighand->siglock, flags);
	85	sigdelset(&current->pending.signal, SIGPIPE);
	86	recalc_sigpending();
	87	spin_unlock_irqrestore(&current->sighand->siglock, flags);
	88	}
	89
	90	return (bytes > 0);
	91	}
fcbf94b9	92
1da177e4 LT	93	static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
	94	struct autofs_wait_queue *wq,
	95	int type)
	96	{
e8514478 IK	97	union {
	98	struct autofs_packet_hdr hdr;
	99	union autofs_packet_union v4_pkt;
	100	union autofs_v5_packet_union v5_pkt;
	101	} pkt;
e64be33c	102	struct file *pipe = NULL;
1da177e4 LT	103	size_t pktsz;
	104
	105	DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
2f84dd70	106	(unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type);
1da177e4 LT	107
	108	memset(&pkt,0,sizeof pkt); /* For security reasons */
	109
	110	pkt.hdr.proto_version = sbi->version;
	111	pkt.hdr.type = type;
87533332	112
5c0a32fc IK	113	switch (type) {
	114	/* Kernel protocol v4 missing and expire packets */
	115	case autofs_ptype_missing:
	116	{
e8514478	117	struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
1da177e4 LT	118
	119	pktsz = sizeof(*mp);
	120
	121	mp->wait_queue_token = wq->wait_queue_token;
70b52a0a JM	122	mp->len = wq->name.len;
	123	memcpy(mp->name, wq->name.name, wq->name.len);
	124	mp->name[wq->name.len] = '\0';
5c0a32fc IK	125	break;
	126	}
	127	case autofs_ptype_expire_multi:
	128	{
e8514478	129	struct autofs_packet_expire_multi *ep = &pkt.v4_pkt.expire_multi;
1da177e4 LT	130
	131	pktsz = sizeof(*ep);
	132
	133	ep->wait_queue_token = wq->wait_queue_token;
70b52a0a JM	134	ep->len = wq->name.len;
	135	memcpy(ep->name, wq->name.name, wq->name.len);
	136	ep->name[wq->name.len] = '\0';
5c0a32fc IK	137	break;
	138	}
	139	/*
	140	* Kernel protocol v5 packet for handling indirect and direct
	141	* mount missing and expire requests
	142	*/
	143	case autofs_ptype_missing_indirect:
	144	case autofs_ptype_expire_indirect:
	145	case autofs_ptype_missing_direct:
	146	case autofs_ptype_expire_direct:
	147	{
e8514478	148	struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
45634cd8	149	struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
5c0a32fc	150
fcbf94b9 LT	151	pktsz = sizeof(*packet);
fcbf94b9 LT	152
5c0a32fc	153	packet->wait_queue_token = wq->wait_queue_token;
70b52a0a JM	154	packet->len = wq->name.len;
	155	memcpy(packet->name, wq->name.name, wq->name.len);
	156	packet->name[wq->name.len] = '\0';
5c0a32fc IK	157	packet->dev = wq->dev;
5c0a32fc IK	158	packet->ino = wq->ino;
45634cd8 EB	159	packet->uid = from_kuid_munged(user_ns, wq->uid);
45634cd8 EB	160	packet->gid = from_kgid_munged(user_ns, wq->gid);
5c0a32fc IK	161	packet->pid = wq->pid;
	162	packet->tgid = wq->tgid;
	163	break;
	164	}
	165	default:
1da177e4	166	printk("autofs4_notify_daemon: bad type %d!\n", type);
87533332	167	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	168	return;
	169	}
	170
cb0942b8	171	pipe = get_file(sbi->pipe);
87533332	172
e64be33c IK	173	mutex_unlock(&sbi->wq_mutex);
e64be33c IK	174
d668dc56	175	if (autofs4_write(sbi, pipe, &pkt, pktsz))
87533332 AV	176	autofs4_catatonic_mode(sbi);
87533332 AV	177	fput(pipe);
1da177e4 LT	178	}
	179
	180	static int autofs4_getpath(struct autofs_sb_info *sbi,
	181	struct dentry dentry, char *name)
	182	{
	183	struct dentry *root = sbi->sb->s_root;
	184	struct dentry *tmp;
949854d0	185	char *buf;
1da177e4	186	char *p;
949854d0 NP	187	int len;
	188	unsigned seq;
	189
	190	rename_retry:
	191	buf = *name;
	192	len = 0;
b5c84bf6	193
949854d0 NP	194	seq = read_seqbegin(&rename_lock);
949854d0 NP	195	rcu_read_lock();
e7854723	196	spin_lock(&sbi->fs_lock);
1da177e4 LT	197	for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
	198	len += tmp->d_name.len + 1;
	199
cab0936a	200	if (!len \|\| --len > NAME_MAX) {
e7854723	201	spin_unlock(&sbi->fs_lock);
949854d0 NP	202	rcu_read_unlock();
	203	if (read_seqretry(&rename_lock, seq))
	204	goto rename_retry;
1da177e4 LT	205	return 0;
	206	}
	207
	208	*(buf + len) = '\0';
	209	p = buf + len - dentry->d_name.len;
	210	strncpy(p, dentry->d_name.name, dentry->d_name.len);
	211
	212	for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
	213	*(--p) = '/';
	214	p -= tmp->d_name.len;
	215	strncpy(p, tmp->d_name.name, tmp->d_name.len);
	216	}
e7854723	217	spin_unlock(&sbi->fs_lock);
949854d0 NP	218	rcu_read_unlock();
	219	if (read_seqretry(&rename_lock, seq))
	220	goto rename_retry;
1da177e4 LT	221
	222	return len;
	223	}
	224
a5370553	225	static struct autofs_wait_queue *
70b52a0a	226	autofs4_find_wait(struct autofs_sb_info sbi, struct qstr qstr)
a5370553 IK	227	{
	228	struct autofs_wait_queue *wq;
	229
	230	for (wq = sbi->queues; wq; wq = wq->next) {
70b52a0a JM	231	if (wq->name.hash == qstr->hash &&
	232	wq->name.len == qstr->len &&
	233	wq->name.name &&
	234	!memcmp(wq->name.name, qstr->name, qstr->len))
a5370553 IK	235	break;
	236	}
	237	return wq;
	238	}
	239
a1362fe9 IK	240	/*
	241	* Check if we have a valid request.
	242	* Returns
	243	* 1 if the request should continue.
	244	* In this case we can return an autofs_wait_queue entry if one is
	245	* found or NULL to idicate a new wait needs to be created.
	246	* 0 or a negative errno if the request shouldn't continue.
	247	*/
	248	static int validate_request(struct autofs_wait_queue **wait,
	249	struct autofs_sb_info *sbi,
	250	struct qstr *qstr,
	251	struct dentry*dentry, enum autofs_notify notify)
	252	{
	253	struct autofs_wait_queue *wq;
	254	struct autofs_info *ino;
	255
4041bcdc AV	256	if (sbi->catatonic)
	257	return -ENOENT;
	258
a1362fe9 IK	259	/* Wait in progress, continue; */
	260	wq = autofs4_find_wait(sbi, qstr);
	261	if (wq) {
	262	*wait = wq;
	263	return 1;
	264	}
	265
	266	*wait = NULL;
	267
	268	/* If we don't yet have any info this is a new request */
	269	ino = autofs4_dentry_ino(dentry);
	270	if (!ino)
	271	return 1;
	272
	273	/*
	274	* If we've been asked to wait on an existing expire (NFY_NONE)
	275	* but there is no wait in the queue ...
	276	*/
	277	if (notify == NFY_NONE) {
	278	/*
	279	* Either we've betean the pending expire to post it's
	280	* wait or it finished while we waited on the mutex.
	281	* So we need to wait till either, the wait appears
	282	* or the expire finishes.
	283	*/
	284
	285	while (ino->flags & AUTOFS_INF_EXPIRING) {
	286	mutex_unlock(&sbi->wq_mutex);
	287	schedule_timeout_interruptible(HZ/10);
	288	if (mutex_lock_interruptible(&sbi->wq_mutex))
	289	return -EINTR;
	290
4041bcdc AV	291	if (sbi->catatonic)
	292	return -ENOENT;
	293
a1362fe9 IK	294	wq = autofs4_find_wait(sbi, qstr);
	295	if (wq) {
	296	*wait = wq;
	297	return 1;
	298	}
	299	}
	300
	301	/*
	302	* Not ideal but the status has already gone. Of the two
	303	* cases where we wait on NFY_NONE neither depend on the
	304	* return status of the wait.
	305	*/
	306	return 0;
	307	}
	308
	309	/*
	310	* If we've been asked to trigger a mount and the request
	311	* completed while we waited on the mutex ...
	312	*/
	313	if (notify == NFY_MOUNT) {
9e3fea16 IK	314	struct dentry *new = NULL;
	315	int valid = 1;
	316
a1362fe9	317	/*
463aea1a IK	318	* If the dentry was successfully mounted while we slept
	319	* on the wait queue mutex we can return success. If it
	320	* isn't mounted (doesn't have submounts for the case of
	321	* a multi-mount with no mount at it's base) we can
	322	* continue on and create a new request.
	323	*/
9e3fea16 IK	324	if (!IS_ROOT(dentry)) {
	325	if (dentry->d_inode && d_unhashed(dentry)) {
	326	struct dentry *parent = dentry->d_parent;
	327	new = d_lookup(parent, &dentry->d_name);
	328	if (new)
	329	dentry = new;
	330	}
	331	}
463aea1a	332	if (have_submounts(dentry))
9e3fea16 IK	333	valid = 0;
	334
	335	if (new)
	336	dput(new);
	337	return valid;
a1362fe9 IK	338	}
	339
	340	return 1;
	341	}
	342
1da177e4 LT	343	int autofs4_wait(struct autofs_sb_info sbi, struct dentry dentry,
	344	enum autofs_notify notify)
	345	{
	346	struct autofs_wait_queue *wq;
70b52a0a	347	struct qstr qstr;
1da177e4	348	char *name;
a1362fe9	349	int status, ret, type;
fbff0870 MS	350	pid_t pid;
fbff0870 MS	351	pid_t tgid;
1da177e4 LT	352
1da177e4 LT	353	/* In catatonic mode, we don't wait for nobody */
e77fbddf	354	if (sbi->catatonic)
1da177e4	355	return -ENOENT;
a1362fe9	356
fbff0870 MS	357	/*
	358	* Try translating pids to the namespace of the daemon.
	359	*
	360	* Zero means failure: we are in an unrelated pid namespace.
	361	*/
	362	pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
	363	tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
	364	if (pid == 0 \|\| tgid == 0)
	365	return -ENOENT;
	366
c72305b5 IK	367	if (!dentry->d_inode) {
	368	/*
	369	* A wait for a negative dentry is invalid for certain
	370	* cases. A direct or offset mount "always" has its mount
	371	* point directory created and so the request dentry must
	372	* be positive or the map key doesn't exist. The situation
	373	* is very similar for indirect mounts except only dentrys
	374	* in the root of the autofs file system may be negative.
	375	*/
a92daf6b	376	if (autofs_type_trigger(sbi->type))
c72305b5 IK	377	return -ENOENT;
	378	else if (!IS_ROOT(dentry->d_parent))
	379	return -ENOENT;
	380	}
eb3b1767	381
1da177e4 LT	382	name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
	383	if (!name)
	384	return -ENOMEM;
	385
5c0a32fc	386	/* If this is a direct mount request create a dummy name */
a92daf6b	387	if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
70b52a0a	388	qstr.len = sprintf(name, "%p", dentry);
5c0a32fc	389	else {
70b52a0a JM	390	qstr.len = autofs4_getpath(sbi, dentry, &name);
70b52a0a JM	391	if (!qstr.len) {
5c0a32fc IK	392	kfree(name);
	393	return -ENOENT;
	394	}
1da177e4	395	}
70b52a0a JM	396	qstr.name = name;
70b52a0a JM	397	qstr.hash = full_name_hash(name, qstr.len);
1da177e4	398
f4c7da02 IK	399	if (mutex_lock_interruptible(&sbi->wq_mutex)) {
f4c7da02 IK	400	kfree(qstr.name);
1da177e4	401	return -EINTR;
f4c7da02	402	}
a5370553	403
a1362fe9 IK	404	ret = validate_request(&wq, sbi, &qstr, dentry, notify);
a1362fe9 IK	405	if (ret <= 0) {
4041bcdc	406	if (ret != -EINTR)
1d5599e3	407	mutex_unlock(&sbi->wq_mutex);
a1362fe9 IK	408	kfree(qstr.name);
a1362fe9 IK	409	return ret;
a5370553	410	}
cc9acc88	411
a5370553	412	if (!wq) {
1da177e4 LT	413	/* Create a new wait queue */
1da177e4 LT	414	wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
e77fbddf	415	if (!wq) {
70b52a0a	416	kfree(qstr.name);
1d5599e3	417	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	418	return -ENOMEM;
	419	}
	420
	421	wq->wait_queue_token = autofs4_next_wait_queue;
	422	if (++autofs4_next_wait_queue == 0)
	423	autofs4_next_wait_queue = 1;
	424	wq->next = sbi->queues;
	425	sbi->queues = wq;
	426	init_waitqueue_head(&wq->queue);
70b52a0a	427	memcpy(&wq->name, &qstr, sizeof(struct qstr));
5c0a32fc IK	428	wq->dev = autofs4_get_dev(sbi);
5c0a32fc IK	429	wq->ino = autofs4_get_ino(sbi);
0eb790e3 DH	430	wq->uid = current_uid();
0eb790e3 DH	431	wq->gid = current_gid();
fbff0870 MS	432	wq->pid = pid;
fbff0870 MS	433	wq->tgid = tgid;
1da177e4	434	wq->status = -EINTR; /* Status return if interrupted */
296f7bf7	435	wq->wait_ctr = 2;
3e7b1919	436
5c0a32fc IK	437	if (sbi->version < 5) {
	438	if (notify == NFY_MOUNT)
	439	type = autofs_ptype_missing;
	440	else
	441	type = autofs_ptype_expire_multi;
	442	} else {
	443	if (notify == NFY_MOUNT)
a92daf6b	444	type = autofs_type_trigger(sbi->type) ?
5c0a32fc IK	445	autofs_ptype_missing_direct :
	446	autofs_ptype_missing_indirect;
	447	else
a92daf6b	448	type = autofs_type_trigger(sbi->type) ?
5c0a32fc IK	449	autofs_ptype_expire_direct :
	450	autofs_ptype_expire_indirect;
	451	}
4dcd00b1	452
682d4fc9	453	DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
70b52a0a JM	454	(unsigned long) wq->wait_queue_token, wq->name.len,
70b52a0a JM	455	wq->name.name, notify);
4dcd00b1	456
606035e7	457	/* autofs4_notify_daemon() may block; it will unlock ->wq_mutex */
4dcd00b1	458	autofs4_notify_daemon(sbi, wq, type);
a5370553	459	} else {
296f7bf7	460	wq->wait_ctr++;
a5370553	461	DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
70b52a0a JM	462	(unsigned long) wq->wait_queue_token, wq->name.len,
70b52a0a JM	463	wq->name.name, notify);
606035e7 AV	464	mutex_unlock(&sbi->wq_mutex);
606035e7 AV	465	kfree(qstr.name);
4dcd00b1 IK	466	}
4dcd00b1 IK	467
5a11d4d0 IK	468	/*
	469	* wq->name.name is NULL iff the lock is already released
	470	* or the mount has been made catatonic.
	471	*/
70b52a0a	472	if (wq->name.name) {
1da177e4 LT	473	/* Block all but "shutdown" signals while waiting */
	474	sigset_t oldset;
	475	unsigned long irqflags;
	476
	477	spin_lock_irqsave(&current->sighand->siglock, irqflags);
	478	oldset = current->blocked;
	479	siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
	480	recalc_sigpending();
	481	spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
	482
70b52a0a	483	wait_event_interruptible(wq->queue, wq->name.name == NULL);
1da177e4 LT	484
	485	spin_lock_irqsave(&current->sighand->siglock, irqflags);
	486	current->blocked = oldset;
	487	recalc_sigpending();
	488	spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
	489	} else {
	490	DPRINTK("skipped sleeping");
	491	}
	492
	493	status = wq->status;
	494
c0f54d3e IK	495	/*
	496	* For direct and offset mounts we need to track the requester's
	497	* uid and gid in the dentry info struct. This is so it can be
	498	* supplied, on request, by the misc device ioctl interface.
	499	* This is needed during daemon resatart when reconnecting
	500	* to existing, active, autofs mounts. The uid and gid (and
	501	* related string values) may be used for macro substitution
	502	* in autofs mount maps.
	503	*/
	504	if (!status) {
	505	struct autofs_info *ino;
	506	struct dentry *de = NULL;
	507
	508	/* direct mount or browsable map */
	509	ino = autofs4_dentry_ino(dentry);
	510	if (!ino) {
	511	/* If not lookup actual dentry used */
	512	de = d_lookup(dentry->d_parent, &dentry->d_name);
	513	if (de)
	514	ino = autofs4_dentry_ino(de);
	515	}
	516
	517	/* Set mount requester */
	518	if (ino) {
	519	spin_lock(&sbi->fs_lock);
	520	ino->uid = wq->uid;
	521	ino->gid = wq->gid;
	522	spin_unlock(&sbi->fs_lock);
	523	}
	524
	525	if (de)
	526	dput(de);
	527	}
	528
1da177e4	529	/* Are we the last process to need status? */
296f7bf7 IK	530	mutex_lock(&sbi->wq_mutex);
296f7bf7 IK	531	if (!--wq->wait_ctr)
1da177e4	532	kfree(wq);
296f7bf7	533	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	534
	535	return status;
	536	}
	537
	538
	539	int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
	540	{
	541	struct autofs_wait_queue wq, *wql;
	542
1d5599e3	543	mutex_lock(&sbi->wq_mutex);
c80544dc	544	for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
e77fbddf	545	if (wq->wait_queue_token == wait_queue_token)
1da177e4 LT	546	break;
	547	}
	548
e77fbddf	549	if (!wq) {
1d5599e3	550	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	551	return -EINVAL;
	552	}
	553
	554	wql = wq->next; / Unlink from chain */
70b52a0a JM	555	kfree(wq->name.name);
70b52a0a JM	556	wq->name.name = NULL; /* Do not wait on this queue */
1da177e4	557	wq->status = status;
296f7bf7 IK	558	wake_up_interruptible(&wq->queue);
296f7bf7 IK	559	if (!--wq->wait_ctr)
1da177e4	560	kfree(wq);
296f7bf7	561	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	562
	563	return 0;
	564	}
	565