autofs: copy autofs4 to autofs

Copy source files from the autofs4 directory to the autofs directory.

Link: http://lkml.kernel.org/r/152626705013.28589.931913083997578251.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 559 insertions, 0 deletions

diff --git a/fs/autofs/waitq.c b/fs/autofs/waitq.c
new file mode 100644
index 000000000000..8a566fa66afe
--- /dev/null
+++ b/fs/autofs/waitq.c
@@ -0,0 +1,559 @@
+/*
+ * 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/sched/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 autofs_next_wait_queue = 1;
+
+void autofs_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 autofs_write(struct autofs_sb_info *sbi,
+			struct file *file, const void *addr, int bytes)
+{
+	unsigned long sigpipe, flags;
+	const char *data = (const char *)addr;
+	ssize_t wr = 0;
+
+	sigpipe = sigismember(&current->pending.signal, SIGPIPE);
+
+	mutex_lock(&sbi->pipe_mutex);
+	while (bytes) {
+		wr = __kernel_write(file, data, bytes, &file->f_pos);
+		if (wr <= 0)
+			break;
+		data += wr;
+		bytes -= wr;
+	}
+	mutex_unlock(&sbi->pipe_mutex);
+
+	/* 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);
+	}
+
+	/* if 'wr' returned 0 (impossible) we assume -EIO (safe) */
+	return bytes == 0 ? 0 : wr < 0 ? wr : -EIO;
+}
+
+static void autofs_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;
+	int ret;
+
+	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);
+
+	switch (ret = autofs_write(sbi, pipe, &pkt, pktsz)) {
+	case 0:
+		break;
+	case -ENOMEM:
+	case -ERESTARTSYS:
+		/* Just fail this one */
+		autofs_wait_release(sbi, wq->wait_queue_token, ret);
+		break;
+	default:
+		autofs_catatonic_mode(sbi);
+		break;
+	}
+	fput(pipe);
+}
+
+static int autofs_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 *
+autofs_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 = autofs_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 = autofs_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 = autofs_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 autofs_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 = autofs_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 = autofs_next_wait_queue;
+		if (++autofs_next_wait_queue == 0)
+			autofs_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 = autofs_get_dev(sbi);
+		wq->ino = autofs_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;
+		}
+
+		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);
+
+		/*
+		 * autofs_notify_daemon() may block; it will unlock ->wq_mutex
+		 */
+		autofs_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.
+	 */
+	wait_event_killable(wq->queue, wq->name.name == NULL);
+	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 = autofs_dentry_ino(dentry);
+		if (!ino) {
+			/* If not lookup actual dentry used */
+			de = d_lookup(dentry->d_parent, &dentry->d_name);
+			if (de)
+				ino = autofs_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 autofs_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(&wq->queue);
+	if (!--wq->wait_ctr)
+		kfree(wq);
+	mutex_unlock(&sbi->wq_mutex);
+
+	return 0;
+}