[mirror_ubuntu-artful-kernel.git] / fs / autofs4 / 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;
	}

	pr_debug("entering catatonic mode\n");

	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 = __vfs_write(file, data, bytes, &file->f_pos);
		if (wr <= 0)
			break;
		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;

	pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
		 (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:
		pr_warn("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, const 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,
			    const struct qstr *qstr,
			    const struct path *path, enum autofs_notify notify)
{
	struct dentry *dentry = path->dentry;
	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;
		struct path this;
		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 (d_unhashed(dentry) &&
			    d_really_is_positive(dentry)) {
				struct dentry *parent = dentry->d_parent;

				new = d_lookup(parent, &dentry->d_name);
				if (new)
					dentry = new;
			}
		}
		this.mnt = path->mnt;
		this.dentry = dentry;
		if (path_has_submounts(&this))
			valid = 0;

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

	return 1;
}

int autofs4_wait(struct autofs_sb_info *sbi,
		 const struct path *path, enum autofs_notify notify)
{
	struct dentry *dentry = path->dentry;
	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 (d_really_is_negative(dentry)) {
		/*
		 * 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(dentry, name, qstr.len);

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

	ret = validate_request(&wq, sbi, &qstr, path, 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_real_cred()->uid;
		wq->gid = current_real_cred()->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;
		}

		pr_debug("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++;
		pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
			 (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 */
		unsigned long shutdown_sigs_mask;
		unsigned long irqflags;
		sigset_t oldset;

		spin_lock_irqsave(&current->sighand->siglock, irqflags);
		oldset = current->blocked;
		shutdown_sigs_mask = SHUTDOWN_SIGS & ~oldset.sig[0];
		siginitsetinv(&current->blocked, shutdown_sigs_mask);
		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 {
		pr_debug("skipped sleeping\n");
	}

	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
e9a7c2f1 IK	1	/*
	2	* Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
	3	* Copyright 2001-2006 Ian Kent <raven@themaw.net>
1da177e4 LT	4	*
	5	* This file is part of the Linux kernel and is made available under
	6	* the terms of the GNU General Public License, version 2, or at your
	7	* option, any later version, incorporated herein by reference.
e9a7c2f1	8	*/
1da177e4 LT	9
	10	#include <linux/slab.h>
	11	#include <linux/time.h>
	12	#include <linux/signal.h>
	13	#include <linux/file.h>
	14	#include "autofs_i.h"
	15
	16	/* We make this a static variable rather than a part of the superblock; it
e9a7c2f1 IK	17	* is better if we don't reassign numbers easily even across filesystems
e9a7c2f1 IK	18	*/
1da177e4 LT	19	static autofs_wqt_t autofs4_next_wait_queue = 1;
	20
	21	/* These are the signals we allow interrupting a pending mount */
	22	#define SHUTDOWN_SIGS (sigmask(SIGKILL) \| sigmask(SIGINT) \| sigmask(SIGQUIT))
	23
	24	void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
	25	{
	26	struct autofs_wait_queue wq, nwq;
	27
5a11d4d0 IK	28	mutex_lock(&sbi->wq_mutex);
	29	if (sbi->catatonic) {
	30	mutex_unlock(&sbi->wq_mutex);
	31	return;
	32	}
	33
8a78d593	34	pr_debug("entering catatonic mode\n");
1da177e4 LT	35
	36	sbi->catatonic = 1;
	37	wq = sbi->queues;
	38	sbi->queues = NULL; /* Erase all wait queues */
e77fbddf	39	while (wq) {
1da177e4 LT	40	nwq = wq->next;
1da177e4 LT	41	wq->status = -ENOENT; /* Magic is gone - report failure */
5140a8ce TG	42	kfree(wq->name.name);
5140a8ce TG	43	wq->name.name = NULL;
296f7bf7	44	wq->wait_ctr--;
1da177e4 LT	45	wake_up_interruptible(&wq->queue);
	46	wq = nwq;
	47	}
ba8df43c IK	48	fput(sbi->pipe); /* Close the pipe */
ba8df43c IK	49	sbi->pipe = NULL;
5a11d4d0 IK	50	sbi->pipefd = -1;
5a11d4d0 IK	51	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	52	}
1da177e4 LT	53
d668dc56 AV	54	static int autofs4_write(struct autofs_sb_info *sbi,
d668dc56 AV	55	struct file file, const void addr, int bytes)
1da177e4 LT	56	{
	57	unsigned long sigpipe, flags;
	58	mm_segment_t fs;
	59	const char data = (const char )addr;
	60	ssize_t wr = 0;
	61
1da177e4 LT	62	sigpipe = sigismember(&current->pending.signal, SIGPIPE);
	63
	64	/* Save pointer to user space and point back to kernel space */
	65	fs = get_fs();
	66	set_fs(KERNEL_DS);
	67
d668dc56	68	mutex_lock(&sbi->pipe_mutex);
5a9294e5 AV	69	while (bytes) {
	70	wr = __vfs_write(file, data, bytes, &file->f_pos);
	71	if (wr <= 0)
	72	break;
1da177e4 LT	73	data += wr;
	74	bytes -= wr;
	75	}
8638094e	76	mutex_unlock(&sbi->pipe_mutex);
1da177e4 LT	77
	78	set_fs(fs);
	79
	80	/* Keep the currently executing process from receiving a
e9a7c2f1 IK	81	* SIGPIPE unless it was already supposed to get one
e9a7c2f1 IK	82	*/
1da177e4 LT	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	}
0266725a	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;
1da177e4 LT	104
8a78d593 IK	105	pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
	106	(unsigned long) wq->wait_queue_token,
	107	wq->name.len, wq->name.name, type);
1da177e4	108
e9a7c2f1	109	memset(&pkt, 0, sizeof(pkt)); /* For security reasons */
1da177e4 LT	110
	111	pkt.hdr.proto_version = sbi->version;
	112	pkt.hdr.type = type;
87533332	113
5c0a32fc IK	114	switch (type) {
	115	/* Kernel protocol v4 missing and expire packets */
	116	case autofs_ptype_missing:
	117	{
e8514478	118	struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
1da177e4 LT	119
	120	pktsz = sizeof(*mp);
	121
	122	mp->wait_queue_token = wq->wait_queue_token;
70b52a0a JM	123	mp->len = wq->name.len;
	124	memcpy(mp->name, wq->name.name, wq->name.len);
	125	mp->name[wq->name.len] = '\0';
5c0a32fc IK	126	break;
	127	}
	128	case autofs_ptype_expire_multi:
	129	{
e9a7c2f1 IK	130	struct autofs_packet_expire_multi *ep =
e9a7c2f1 IK	131	&pkt.v4_pkt.expire_multi;
1da177e4 LT	132
	133	pktsz = sizeof(*ep);
	134
	135	ep->wait_queue_token = wq->wait_queue_token;
70b52a0a JM	136	ep->len = wq->name.len;
	137	memcpy(ep->name, wq->name.name, wq->name.len);
	138	ep->name[wq->name.len] = '\0';
5c0a32fc IK	139	break;
	140	}
	141	/*
	142	* Kernel protocol v5 packet for handling indirect and direct
	143	* mount missing and expire requests
	144	*/
	145	case autofs_ptype_missing_indirect:
	146	case autofs_ptype_expire_indirect:
	147	case autofs_ptype_missing_direct:
	148	case autofs_ptype_expire_direct:
	149	{
e8514478	150	struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
45634cd8	151	struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
5c0a32fc	152
fcbf94b9 LT	153	pktsz = sizeof(*packet);
fcbf94b9 LT	154
5c0a32fc	155	packet->wait_queue_token = wq->wait_queue_token;
70b52a0a JM	156	packet->len = wq->name.len;
	157	memcpy(packet->name, wq->name.name, wq->name.len);
	158	packet->name[wq->name.len] = '\0';
5c0a32fc IK	159	packet->dev = wq->dev;
5c0a32fc IK	160	packet->ino = wq->ino;
45634cd8 EB	161	packet->uid = from_kuid_munged(user_ns, wq->uid);
45634cd8 EB	162	packet->gid = from_kgid_munged(user_ns, wq->gid);
5c0a32fc IK	163	packet->pid = wq->pid;
	164	packet->tgid = wq->tgid;
	165	break;
	166	}
	167	default:
8a78d593	168	pr_warn("bad type %d!\n", type);
87533332	169	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	170	return;
	171	}
	172
cb0942b8	173	pipe = get_file(sbi->pipe);
87533332	174
e64be33c IK	175	mutex_unlock(&sbi->wq_mutex);
e64be33c IK	176
d668dc56	177	if (autofs4_write(sbi, pipe, &pkt, pktsz))
87533332 AV	178	autofs4_catatonic_mode(sbi);
87533332 AV	179	fput(pipe);
1da177e4 LT	180	}
	181
	182	static int autofs4_getpath(struct autofs_sb_info *sbi,
	183	struct dentry dentry, char *name)
	184	{
	185	struct dentry *root = sbi->sb->s_root;
	186	struct dentry *tmp;
949854d0	187	char *buf;
1da177e4	188	char *p;
949854d0 NP	189	int len;
	190	unsigned seq;
	191
	192	rename_retry:
	193	buf = *name;
	194	len = 0;
b5c84bf6	195
949854d0 NP	196	seq = read_seqbegin(&rename_lock);
949854d0 NP	197	rcu_read_lock();
e7854723	198	spin_lock(&sbi->fs_lock);
1da177e4 LT	199	for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
	200	len += tmp->d_name.len + 1;
	201
cab0936a	202	if (!len \|\| --len > NAME_MAX) {
e7854723	203	spin_unlock(&sbi->fs_lock);
949854d0 NP	204	rcu_read_unlock();
	205	if (read_seqretry(&rename_lock, seq))
	206	goto rename_retry;
1da177e4 LT	207	return 0;
	208	}
	209
	210	*(buf + len) = '\0';
	211	p = buf + len - dentry->d_name.len;
	212	strncpy(p, dentry->d_name.name, dentry->d_name.len);
	213
	214	for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
	215	*(--p) = '/';
	216	p -= tmp->d_name.len;
	217	strncpy(p, tmp->d_name.name, tmp->d_name.len);
	218	}
e7854723	219	spin_unlock(&sbi->fs_lock);
949854d0 NP	220	rcu_read_unlock();
	221	if (read_seqretry(&rename_lock, seq))
	222	goto rename_retry;
1da177e4 LT	223
	224	return len;
	225	}
	226
a5370553	227	static struct autofs_wait_queue *
8ac790f3	228	autofs4_find_wait(struct autofs_sb_info sbi, const struct qstr qstr)
a5370553 IK	229	{
	230	struct autofs_wait_queue *wq;
	231
	232	for (wq = sbi->queues; wq; wq = wq->next) {
70b52a0a JM	233	if (wq->name.hash == qstr->hash &&
	234	wq->name.len == qstr->len &&
	235	wq->name.name &&
e9a7c2f1	236	!memcmp(wq->name.name, qstr->name, qstr->len))
a5370553 IK	237	break;
	238	}
	239	return wq;
	240	}
	241
a1362fe9 IK	242	/*
	243	* Check if we have a valid request.
	244	* Returns
	245	* 1 if the request should continue.
	246	* In this case we can return an autofs_wait_queue entry if one is
	247	* found or NULL to idicate a new wait needs to be created.
	248	* 0 or a negative errno if the request shouldn't continue.
	249	*/
	250	static int validate_request(struct autofs_wait_queue **wait,
	251	struct autofs_sb_info *sbi,
8ac790f3	252	const struct qstr *qstr,
60359741	253	const struct path *path, enum autofs_notify notify)
a1362fe9	254	{
60359741	255	struct dentry *dentry = path->dentry;
a1362fe9 IK	256	struct autofs_wait_queue *wq;
	257	struct autofs_info *ino;
	258
4041bcdc AV	259	if (sbi->catatonic)
	260	return -ENOENT;
	261
a1362fe9 IK	262	/* Wait in progress, continue; */
	263	wq = autofs4_find_wait(sbi, qstr);
	264	if (wq) {
	265	*wait = wq;
	266	return 1;
	267	}
	268
	269	*wait = NULL;
	270
	271	/* If we don't yet have any info this is a new request */
	272	ino = autofs4_dentry_ino(dentry);
	273	if (!ino)
	274	return 1;
	275
	276	/*
	277	* If we've been asked to wait on an existing expire (NFY_NONE)
	278	* but there is no wait in the queue ...
	279	*/
	280	if (notify == NFY_NONE) {
	281	/*
	282	* Either we've betean the pending expire to post it's
	283	* wait or it finished while we waited on the mutex.
	284	* So we need to wait till either, the wait appears
	285	* or the expire finishes.
	286	*/
	287
	288	while (ino->flags & AUTOFS_INF_EXPIRING) {
	289	mutex_unlock(&sbi->wq_mutex);
	290	schedule_timeout_interruptible(HZ/10);
	291	if (mutex_lock_interruptible(&sbi->wq_mutex))
	292	return -EINTR;
	293
4041bcdc AV	294	if (sbi->catatonic)
	295	return -ENOENT;
	296
a1362fe9 IK	297	wq = autofs4_find_wait(sbi, qstr);
	298	if (wq) {
	299	*wait = wq;
	300	return 1;
	301	}
	302	}
	303
	304	/*
	305	* Not ideal but the status has already gone. Of the two
	306	* cases where we wait on NFY_NONE neither depend on the
	307	* return status of the wait.
	308	*/
	309	return 0;
	310	}
	311
	312	/*
	313	* If we've been asked to trigger a mount and the request
	314	* completed while we waited on the mutex ...
	315	*/
	316	if (notify == NFY_MOUNT) {
9e3fea16	317	struct dentry *new = NULL;
60359741	318	struct path this;
9e3fea16 IK	319	int valid = 1;
9e3fea16 IK	320
a1362fe9	321	/*
463aea1a IK	322	* If the dentry was successfully mounted while we slept
	323	* on the wait queue mutex we can return success. If it
	324	* isn't mounted (doesn't have submounts for the case of
	325	* a multi-mount with no mount at it's base) we can
	326	* continue on and create a new request.
	327	*/
9e3fea16	328	if (!IS_ROOT(dentry)) {
e9a7c2f1 IK	329	if (d_unhashed(dentry) &&
e9a7c2f1 IK	330	d_really_is_positive(dentry)) {
9e3fea16	331	struct dentry *parent = dentry->d_parent;
e9a7c2f1	332
9e3fea16 IK	333	new = d_lookup(parent, &dentry->d_name);
	334	if (new)
	335	dentry = new;
	336	}
	337	}
60359741 IK	338	this.mnt = path->mnt;
	339	this.dentry = dentry;
	340	if (path_has_submounts(&this))
9e3fea16 IK	341	valid = 0;
	342
	343	if (new)
	344	dput(new);
	345	return valid;
a1362fe9 IK	346	}
	347
	348	return 1;
	349	}
	350
e9a7c2f1	351	int autofs4_wait(struct autofs_sb_info *sbi,
dd36a882	352	const struct path *path, enum autofs_notify notify)
1da177e4	353	{
dd36a882	354	struct dentry *dentry = path->dentry;
1da177e4	355	struct autofs_wait_queue *wq;
70b52a0a	356	struct qstr qstr;
1da177e4	357	char *name;
a1362fe9	358	int status, ret, type;
fbff0870 MS	359	pid_t pid;
fbff0870 MS	360	pid_t tgid;
1da177e4 LT	361
1da177e4 LT	362	/* In catatonic mode, we don't wait for nobody */
e77fbddf	363	if (sbi->catatonic)
1da177e4	364	return -ENOENT;
a1362fe9	365
fbff0870 MS	366	/*
	367	* Try translating pids to the namespace of the daemon.
	368	*
	369	* Zero means failure: we are in an unrelated pid namespace.
	370	*/
	371	pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
	372	tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
	373	if (pid == 0 \|\| tgid == 0)
	374	return -ENOENT;
	375
2b0143b5	376	if (d_really_is_negative(dentry)) {
c72305b5 IK	377	/*
	378	* A wait for a negative dentry is invalid for certain
	379	* cases. A direct or offset mount "always" has its mount
	380	* point directory created and so the request dentry must
	381	* be positive or the map key doesn't exist. The situation
	382	* is very similar for indirect mounts except only dentrys
	383	* in the root of the autofs file system may be negative.
	384	*/
a92daf6b	385	if (autofs_type_trigger(sbi->type))
c72305b5 IK	386	return -ENOENT;
	387	else if (!IS_ROOT(dentry->d_parent))
	388	return -ENOENT;
	389	}
eb3b1767	390
1da177e4 LT	391	name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
	392	if (!name)
	393	return -ENOMEM;
	394
5c0a32fc	395	/* If this is a direct mount request create a dummy name */
a92daf6b	396	if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
70b52a0a	397	qstr.len = sprintf(name, "%p", dentry);
5c0a32fc	398	else {
70b52a0a JM	399	qstr.len = autofs4_getpath(sbi, dentry, &name);
70b52a0a JM	400	if (!qstr.len) {
5c0a32fc IK	401	kfree(name);
	402	return -ENOENT;
	403	}
1da177e4	404	}
70b52a0a	405	qstr.name = name;
8387ff25	406	qstr.hash = full_name_hash(dentry, name, qstr.len);
1da177e4	407
f4c7da02 IK	408	if (mutex_lock_interruptible(&sbi->wq_mutex)) {
f4c7da02 IK	409	kfree(qstr.name);
1da177e4	410	return -EINTR;
f4c7da02	411	}
a5370553	412
60359741	413	ret = validate_request(&wq, sbi, &qstr, path, notify);
a1362fe9	414	if (ret <= 0) {
4041bcdc	415	if (ret != -EINTR)
1d5599e3	416	mutex_unlock(&sbi->wq_mutex);
a1362fe9 IK	417	kfree(qstr.name);
a1362fe9 IK	418	return ret;
a5370553	419	}
cc9acc88	420
a5370553	421	if (!wq) {
1da177e4	422	/* Create a new wait queue */
e9a7c2f1	423	wq = kmalloc(sizeof(struct autofs_wait_queue), GFP_KERNEL);
e77fbddf	424	if (!wq) {
70b52a0a	425	kfree(qstr.name);
1d5599e3	426	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	427	return -ENOMEM;
	428	}
	429
	430	wq->wait_queue_token = autofs4_next_wait_queue;
	431	if (++autofs4_next_wait_queue == 0)
	432	autofs4_next_wait_queue = 1;
	433	wq->next = sbi->queues;
	434	sbi->queues = wq;
	435	init_waitqueue_head(&wq->queue);
70b52a0a	436	memcpy(&wq->name, &qstr, sizeof(struct qstr));
5c0a32fc IK	437	wq->dev = autofs4_get_dev(sbi);
5c0a32fc IK	438	wq->ino = autofs4_get_ino(sbi);
069d5ac9 EB	439	wq->uid = current_real_cred()->uid;
069d5ac9 EB	440	wq->gid = current_real_cred()->gid;
fbff0870 MS	441	wq->pid = pid;
fbff0870 MS	442	wq->tgid = tgid;
1da177e4	443	wq->status = -EINTR; /* Status return if interrupted */
296f7bf7	444	wq->wait_ctr = 2;
3e7b1919	445
5c0a32fc IK	446	if (sbi->version < 5) {
	447	if (notify == NFY_MOUNT)
	448	type = autofs_ptype_missing;
	449	else
	450	type = autofs_ptype_expire_multi;
	451	} else {
	452	if (notify == NFY_MOUNT)
a92daf6b	453	type = autofs_type_trigger(sbi->type) ?
5c0a32fc IK	454	autofs_ptype_missing_direct :
	455	autofs_ptype_missing_indirect;
	456	else
a92daf6b	457	type = autofs_type_trigger(sbi->type) ?
5c0a32fc IK	458	autofs_ptype_expire_direct :
	459	autofs_ptype_expire_indirect;
	460	}
4dcd00b1	461
8a78d593 IK	462	pr_debug("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
	463	(unsigned long) wq->wait_queue_token, wq->name.len,
	464	wq->name.name, notify);
4dcd00b1	465
e9a7c2f1 IK	466	/*
	467	* autofs4_notify_daemon() may block; it will unlock ->wq_mutex
	468	*/
4dcd00b1	469	autofs4_notify_daemon(sbi, wq, type);
a5370553	470	} else {
296f7bf7	471	wq->wait_ctr++;
8a78d593 IK	472	pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
	473	(unsigned long) wq->wait_queue_token, wq->name.len,
	474	wq->name.name, notify);
606035e7 AV	475	mutex_unlock(&sbi->wq_mutex);
606035e7 AV	476	kfree(qstr.name);
4dcd00b1 IK	477	}
4dcd00b1 IK	478
5a11d4d0 IK	479	/*
	480	* wq->name.name is NULL iff the lock is already released
	481	* or the mount has been made catatonic.
	482	*/
70b52a0a	483	if (wq->name.name) {
1da177e4	484	/* Block all but "shutdown" signals while waiting */
b3f67a98	485	unsigned long shutdown_sigs_mask;
1da177e4	486	unsigned long irqflags;
b3f67a98	487	sigset_t oldset;
1da177e4 LT	488
	489	spin_lock_irqsave(&current->sighand->siglock, irqflags);
	490	oldset = current->blocked;
b3f67a98 IK	491	shutdown_sigs_mask = SHUTDOWN_SIGS & ~oldset.sig[0];
b3f67a98 IK	492	siginitsetinv(&current->blocked, shutdown_sigs_mask);
1da177e4 LT	493	recalc_sigpending();
	494	spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
	495
70b52a0a	496	wait_event_interruptible(wq->queue, wq->name.name == NULL);
1da177e4 LT	497
	498	spin_lock_irqsave(&current->sighand->siglock, irqflags);
	499	current->blocked = oldset;
	500	recalc_sigpending();
	501	spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
	502	} else {
8a78d593	503	pr_debug("skipped sleeping\n");
1da177e4 LT	504	}
	505
	506	status = wq->status;
	507
c0f54d3e IK	508	/*
	509	* For direct and offset mounts we need to track the requester's
	510	* uid and gid in the dentry info struct. This is so it can be
	511	* supplied, on request, by the misc device ioctl interface.
	512	* This is needed during daemon resatart when reconnecting
	513	* to existing, active, autofs mounts. The uid and gid (and
	514	* related string values) may be used for macro substitution
	515	* in autofs mount maps.
	516	*/
	517	if (!status) {
	518	struct autofs_info *ino;
	519	struct dentry *de = NULL;
	520
	521	/* direct mount or browsable map */
	522	ino = autofs4_dentry_ino(dentry);
	523	if (!ino) {
	524	/* If not lookup actual dentry used */
	525	de = d_lookup(dentry->d_parent, &dentry->d_name);
	526	if (de)
	527	ino = autofs4_dentry_ino(de);
	528	}
	529
	530	/* Set mount requester */
	531	if (ino) {
	532	spin_lock(&sbi->fs_lock);
	533	ino->uid = wq->uid;
	534	ino->gid = wq->gid;
	535	spin_unlock(&sbi->fs_lock);
	536	}
	537
	538	if (de)
	539	dput(de);
	540	}
	541
1da177e4	542	/* Are we the last process to need status? */
296f7bf7 IK	543	mutex_lock(&sbi->wq_mutex);
296f7bf7 IK	544	if (!--wq->wait_ctr)
1da177e4	545	kfree(wq);
296f7bf7	546	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	547
	548	return status;
	549	}
	550
	551
	552	int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
	553	{
	554	struct autofs_wait_queue wq, *wql;
	555
1d5599e3	556	mutex_lock(&sbi->wq_mutex);
c80544dc	557	for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
e77fbddf	558	if (wq->wait_queue_token == wait_queue_token)
1da177e4 LT	559	break;
	560	}
	561
e77fbddf	562	if (!wq) {
1d5599e3	563	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	564	return -EINVAL;
	565	}
	566
	567	wql = wq->next; / Unlink from chain */
70b52a0a JM	568	kfree(wq->name.name);
70b52a0a JM	569	wq->name.name = NULL; /* Do not wait on this queue */
1da177e4	570	wq->status = status;
296f7bf7 IK	571	wake_up_interruptible(&wq->queue);
296f7bf7 IK	572	if (!--wq->wait_ctr)
1da177e4	573	kfree(wq);
296f7bf7	574	mutex_unlock(&sbi->wq_mutex);
1da177e4 LT	575
	576	return 0;
	577	}