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.netSigned-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>

fs/autofs/autofs_i.h

+/*
+ *  Copyright 1997-1998 Transmeta Corporation - All Rights Reserved
+ *  Copyright 2005-2006 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.
+ */
+
+/* Internal header file for autofs */
+
+#include <linux/auto_fs.h>
+#include <linux/auto_dev-ioctl.h>
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/string.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/uaccess.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/completion.h>
+#include <asm/current.h>
+
+/* This is the range of ioctl() numbers we claim as ours */
+#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
+#define AUTOFS_IOC_COUNT     32
+
+#define AUTOFS_DEV_IOCTL_IOC_FIRST	(AUTOFS_DEV_IOCTL_VERSION)
+#define AUTOFS_DEV_IOCTL_IOC_COUNT \
+	(AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD - AUTOFS_DEV_IOCTL_VERSION_CMD)
+
+#ifdef pr_fmt
+#undef pr_fmt
+#endif
+#define pr_fmt(fmt) KBUILD_MODNAME ":pid:%d:%s: " fmt, current->pid, __func__
+
+/*
+ * Unified info structure.  This is pointed to by both the dentry and
+ * inode structures.  Each file in the filesystem has an instance of this
+ * structure.  It holds a reference to the dentry, so dentries are never
+ * flushed while the file exists.  All name lookups are dealt with at the
+ * dentry level, although the filesystem can interfere in the validation
+ * process.  Readdir is implemented by traversing the dentry lists.
+ */
+struct autofs_info {
+	struct dentry	*dentry;
+	struct inode	*inode;
+
+	int		flags;
+
+	struct completion expire_complete;
+
+	struct list_head active;
+	int active_count;
+
+	struct list_head expiring;
+
+	struct autofs_sb_info *sbi;
+	unsigned long last_used;
+	atomic_t count;
+
+	kuid_t uid;
+	kgid_t gid;
+};
+
+#define AUTOFS_INF_EXPIRING	(1<<0) /* dentry in the process of expiring */
+#define AUTOFS_INF_WANT_EXPIRE	(1<<1) /* the dentry is being considered
+					* for expiry, so RCU_walk is
+					* not permitted.  If it progresses to
+					* actual expiry attempt, the flag is
+					* not cleared when EXPIRING is set -
+					* in that case it gets cleared only
+					* when it comes to clearing EXPIRING.
+					*/
+#define AUTOFS_INF_PENDING	(1<<2) /* dentry pending mount */
+
+struct autofs_wait_queue {
+	wait_queue_head_t queue;
+	struct autofs_wait_queue *next;
+	autofs_wqt_t wait_queue_token;
+	/* We use the following to see what we are waiting for */
+	struct qstr name;
+	u32 dev;
+	u64 ino;
+	kuid_t uid;
+	kgid_t gid;
+	pid_t pid;
+	pid_t tgid;
+	/* This is for status reporting upon return */
+	int status;
+	unsigned int wait_ctr;
+};
+
+#define AUTOFS_SBI_MAGIC 0x6d4a556d
+
+struct autofs_sb_info {
+	u32 magic;
+	int pipefd;
+	struct file *pipe;
+	struct pid *oz_pgrp;
+	int catatonic;
+	int version;
+	int sub_version;
+	int min_proto;
+	int max_proto;
+	unsigned long exp_timeout;
+	unsigned int type;
+	struct super_block *sb;
+	struct mutex wq_mutex;
+	struct mutex pipe_mutex;
+	spinlock_t fs_lock;
+	struct autofs_wait_queue *queues; /* Wait queue pointer */
+	spinlock_t lookup_lock;
+	struct list_head active_list;
+	struct list_head expiring_list;
+	struct rcu_head rcu;
+};
+
+static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb)
+{
+	return (struct autofs_sb_info *)(sb->s_fs_info);
+}
+
+static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry)
+{
+	return (struct autofs_info *)(dentry->d_fsdata);
+}
+
+/* autofs_oz_mode(): do we see the man behind the curtain?  (The
+ * processes which do manipulations for us in user space sees the raw
+ * filesystem without "magic".)
+ */
+static inline int autofs_oz_mode(struct autofs_sb_info *sbi)
+{
+	return sbi->catatonic || task_pgrp(current) == sbi->oz_pgrp;
+}
+
+struct inode *autofs_get_inode(struct super_block *, umode_t);
+void autofs_free_ino(struct autofs_info *);
+
+/* Expiration */
+int is_autofs_dentry(struct dentry *);
+int autofs_expire_wait(const struct path *path, int rcu_walk);
+int autofs_expire_run(struct super_block *, struct vfsmount *,
+		      struct autofs_sb_info *,
+		      struct autofs_packet_expire __user *);
+int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+			   struct autofs_sb_info *sbi, int when);
+int autofs_expire_multi(struct super_block *, struct vfsmount *,
+			struct autofs_sb_info *, int __user *);
+struct dentry *autofs_expire_direct(struct super_block *sb,
+				    struct vfsmount *mnt,
+				    struct autofs_sb_info *sbi, int how);
+struct dentry *autofs_expire_indirect(struct super_block *sb,
+				      struct vfsmount *mnt,
+				      struct autofs_sb_info *sbi, int how);
+
+/* Device node initialization */
+
+int autofs_dev_ioctl_init(void);
+void autofs_dev_ioctl_exit(void);
+
+/* Operations structures */
+
+extern const struct inode_operations autofs_symlink_inode_operations;
+extern const struct inode_operations autofs_dir_inode_operations;
+extern const struct file_operations autofs_dir_operations;
+extern const struct file_operations autofs_root_operations;
+extern const struct dentry_operations autofs_dentry_operations;
+
+/* VFS automount flags management functions */
+static inline void __managed_dentry_set_managed(struct dentry *dentry)
+{
+	dentry->d_flags |= (DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
+}
+
+static inline void managed_dentry_set_managed(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	__managed_dentry_set_managed(dentry);
+	spin_unlock(&dentry->d_lock);
+}
+
+static inline void __managed_dentry_clear_managed(struct dentry *dentry)
+{
+	dentry->d_flags &= ~(DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT);
+}
+
+static inline void managed_dentry_clear_managed(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	__managed_dentry_clear_managed(dentry);
+	spin_unlock(&dentry->d_lock);
+}
+
+/* Initializing function */
+
+int autofs_fill_super(struct super_block *, void *, int);
+struct autofs_info *autofs_new_ino(struct autofs_sb_info *);
+void autofs_clean_ino(struct autofs_info *);
+
+static inline int autofs_prepare_pipe(struct file *pipe)
+{
+	if (!(pipe->f_mode & FMODE_CAN_WRITE))
+		return -EINVAL;
+	if (!S_ISFIFO(file_inode(pipe)->i_mode))
+		return -EINVAL;
+	/* We want a packet pipe */
+	pipe->f_flags |= O_DIRECT;
+	return 0;
+}
+
+/* Queue management functions */
+
+int autofs_wait(struct autofs_sb_info *,
+		 const struct path *, enum autofs_notify);
+int autofs_wait_release(struct autofs_sb_info *, autofs_wqt_t, int);
+void autofs_catatonic_mode(struct autofs_sb_info *);
+
+static inline u32 autofs_get_dev(struct autofs_sb_info *sbi)
+{
+	return new_encode_dev(sbi->sb->s_dev);
+}
+
+static inline u64 autofs_get_ino(struct autofs_sb_info *sbi)
+{
+	return d_inode(sbi->sb->s_root)->i_ino;
+}
+
+static inline void __autofs_add_expiring(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+
+	if (ino) {
+		if (list_empty(&ino->expiring))
+			list_add(&ino->expiring, &sbi->expiring_list);
+	}
+}
+
+static inline void autofs_add_expiring(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+
+	if (ino) {
+		spin_lock(&sbi->lookup_lock);
+		if (list_empty(&ino->expiring))
+			list_add(&ino->expiring, &sbi->expiring_list);
+		spin_unlock(&sbi->lookup_lock);
+	}
+}
+
+static inline void autofs_del_expiring(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+
+	if (ino) {
+		spin_lock(&sbi->lookup_lock);
+		if (!list_empty(&ino->expiring))
+			list_del_init(&ino->expiring);
+		spin_unlock(&sbi->lookup_lock);
+	}
+}
+
+void autofs_kill_sb(struct super_block *);

fs/autofs/dev-ioctl.c

+/*
+ * Copyright 2008 Red Hat, Inc. All rights reserved.
+ * Copyright 2008 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/module.h>
+#include <linux/vmalloc.h>
+#include <linux/miscdevice.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/namei.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/compat.h>
+#include <linux/syscalls.h>
+#include <linux/magic.h>
+#include <linux/dcache.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+
+#include "autofs_i.h"
+
+/*
+ * This module implements an interface for routing autofs ioctl control
+ * commands via a miscellaneous device file.
+ *
+ * The alternate interface is needed because we need to be able open
+ * an ioctl file descriptor on an autofs mount that may be covered by
+ * another mount. This situation arises when starting automount(8)
+ * or other user space daemon which uses direct mounts or offset
+ * mounts (used for autofs lazy mount/umount of nested mount trees),
+ * which have been left busy at at service shutdown.
+ */
+
+typedef int (*ioctl_fn)(struct file *, struct autofs_sb_info *,
+			struct autofs_dev_ioctl *);
+
+static int check_name(const char *name)
+{
+	if (!strchr(name, '/'))
+		return -EINVAL;
+	return 0;
+}
+
+/*
+ * Check a string doesn't overrun the chunk of
+ * memory we copied from user land.
+ */
+static int invalid_str(char *str, size_t size)
+{
+	if (memchr(str, 0, size))
+		return 0;
+	return -EINVAL;
+}
+
+/*
+ * Check that the user compiled against correct version of autofs
+ * misc device code.
+ *
+ * As well as checking the version compatibility this always copies
+ * the kernel interface version out.
+ */
+static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
+{
+	int err = 0;
+
+	if ((param->ver_major != AUTOFS_DEV_IOCTL_VERSION_MAJOR) ||
+	    (param->ver_minor > AUTOFS_DEV_IOCTL_VERSION_MINOR)) {
+		pr_warn("ioctl control interface version mismatch: "
+			"kernel(%u.%u), user(%u.%u), cmd(0x%08x)\n",
+			AUTOFS_DEV_IOCTL_VERSION_MAJOR,
+			AUTOFS_DEV_IOCTL_VERSION_MINOR,
+			param->ver_major, param->ver_minor, cmd);
+		err = -EINVAL;
+	}
+
+	/* Fill in the kernel version. */
+	param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
+	param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
+
+	return err;
+}
+
+/*
+ * Copy parameter control struct, including a possible path allocated
+ * at the end of the struct.
+ */
+static struct autofs_dev_ioctl *
+copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
+{
+	struct autofs_dev_ioctl tmp, *res;
+
+	if (copy_from_user(&tmp, in, AUTOFS_DEV_IOCTL_SIZE))
+		return ERR_PTR(-EFAULT);
+
+	if (tmp.size < AUTOFS_DEV_IOCTL_SIZE)
+		return ERR_PTR(-EINVAL);
+
+	if (tmp.size > AUTOFS_DEV_IOCTL_SIZE + PATH_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	res = memdup_user(in, tmp.size);
+	if (!IS_ERR(res))
+		res->size = tmp.size;
+
+	return res;
+}
+
+static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
+{
+	kfree(param);
+}
+
+/*
+ * Check sanity of parameter control fields and if a path is present
+ * check that it is terminated and contains at least one "/".
+ */
+static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
+{
+	int err;
+
+	err = check_dev_ioctl_version(cmd, param);
+	if (err) {
+		pr_warn("invalid device control module version "
+			"supplied for cmd(0x%08x)\n", cmd);
+		goto out;
+	}
+
+	if (param->size > AUTOFS_DEV_IOCTL_SIZE) {
+		err = invalid_str(param->path, param->size - AUTOFS_DEV_IOCTL_SIZE);
+		if (err) {
+			pr_warn(
+			  "path string terminator missing for cmd(0x%08x)\n",
+			  cmd);
+			goto out;
+		}
+
+		err = check_name(param->path);
+		if (err) {
+			pr_warn("invalid path supplied for cmd(0x%08x)\n",
+				cmd);
+			goto out;
+		}
+	}
+
+	err = 0;
+out:
+	return err;
+}
+
+/*
+ * Get the autofs super block info struct from the file opened on
+ * the autofs mount point.
+ */
+static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
+{
+	struct autofs_sb_info *sbi = NULL;
+	struct inode *inode;
+
+	if (f) {
+		inode = file_inode(f);
+		sbi = autofs_sbi(inode->i_sb);
+	}
+	return sbi;
+}
+
+/* Return autofs dev ioctl version */
+static int autofs_dev_ioctl_version(struct file *fp,
+				    struct autofs_sb_info *sbi,
+				    struct autofs_dev_ioctl *param)
+{
+	/* This should have already been set. */
+	param->ver_major = AUTOFS_DEV_IOCTL_VERSION_MAJOR;
+	param->ver_minor = AUTOFS_DEV_IOCTL_VERSION_MINOR;
+	return 0;
+}
+
+/* Return autofs module protocol version */
+static int autofs_dev_ioctl_protover(struct file *fp,
+				     struct autofs_sb_info *sbi,
+				     struct autofs_dev_ioctl *param)
+{
+	param->protover.version = sbi->version;
+	return 0;
+}
+
+/* Return autofs module protocol sub version */
+static int autofs_dev_ioctl_protosubver(struct file *fp,
+					struct autofs_sb_info *sbi,
+					struct autofs_dev_ioctl *param)
+{
+	param->protosubver.sub_version = sbi->sub_version;
+	return 0;
+}
+
+/* Find the topmost mount satisfying test() */
+static int find_autofs_mount(const char *pathname,
+			     struct path *res,
+			     int test(const struct path *path, void *data),
+			     void *data)
+{
+	struct path path;
+	int err;
+
+	err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
+	if (err)
+		return err;
+	err = -ENOENT;
+	while (path.dentry == path.mnt->mnt_root) {
+		if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
+			if (test(&path, data)) {
+				path_get(&path);
+				*res = path;
+				err = 0;
+				break;
+			}
+		}
+		if (!follow_up(&path))
+			break;
+	}
+	path_put(&path);
+	return err;
+}
+
+static int test_by_dev(const struct path *path, void *p)
+{
+	return path->dentry->d_sb->s_dev == *(dev_t *)p;
+}
+
+static int test_by_type(const struct path *path, void *p)
+{
+	struct autofs_info *ino = autofs_dentry_ino(path->dentry);
+
+	return ino && ino->sbi->type & *(unsigned *)p;
+}
+
+/*
+ * Open a file descriptor on the autofs mount point corresponding
+ * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
+ */
+static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
+{
+	int err, fd;
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (likely(fd >= 0)) {
+		struct file *filp;
+		struct path path;
+
+		err = find_autofs_mount(name, &path, test_by_dev, &devid);
+		if (err)
+			goto out;
+
+		filp = dentry_open(&path, O_RDONLY, current_cred());
+		path_put(&path);
+		if (IS_ERR(filp)) {
+			err = PTR_ERR(filp);
+			goto out;
+		}
+
+		fd_install(fd, filp);
+	}
+
+	return fd;
+
+out:
+	put_unused_fd(fd);
+	return err;
+}
+
+/* Open a file descriptor on an autofs mount point */
+static int autofs_dev_ioctl_openmount(struct file *fp,
+				      struct autofs_sb_info *sbi,
+				      struct autofs_dev_ioctl *param)
+{
+	const char *path;
+	dev_t devid;
+	int err, fd;
+
+	/* param->path has already been checked */
+	if (!param->openmount.devid)
+		return -EINVAL;
+
+	param->ioctlfd = -1;
+
+	path = param->path;
+	devid = new_decode_dev(param->openmount.devid);
+
+	err = 0;
+	fd = autofs_dev_ioctl_open_mountpoint(path, devid);
+	if (unlikely(fd < 0)) {
+		err = fd;
+		goto out;
+	}
+
+	param->ioctlfd = fd;
+out:
+	return err;
+}
+
+/* Close file descriptor allocated above (user can also use close(2)). */
+static int autofs_dev_ioctl_closemount(struct file *fp,
+				       struct autofs_sb_info *sbi,
+				       struct autofs_dev_ioctl *param)
+{
+	return ksys_close(param->ioctlfd);
+}
+
+/*
+ * Send "ready" status for an existing wait (either a mount or an expire
+ * request).
+ */
+static int autofs_dev_ioctl_ready(struct file *fp,
+				  struct autofs_sb_info *sbi,
+				  struct autofs_dev_ioctl *param)
+{
+	autofs_wqt_t token;
+
+	token = (autofs_wqt_t) param->ready.token;
+	return autofs_wait_release(sbi, token, 0);
+}
+
+/*
+ * Send "fail" status for an existing wait (either a mount or an expire
+ * request).
+ */
+static int autofs_dev_ioctl_fail(struct file *fp,
+				 struct autofs_sb_info *sbi,
+				 struct autofs_dev_ioctl *param)
+{
+	autofs_wqt_t token;
+	int status;
+
+	token = (autofs_wqt_t) param->fail.token;
+	status = param->fail.status < 0 ? param->fail.status : -ENOENT;
+	return autofs_wait_release(sbi, token, status);
+}
+
+/*
+ * Set the pipe fd for kernel communication to the daemon.
+ *
+ * Normally this is set at mount using an option but if we
+ * are reconnecting to a busy mount then we need to use this
+ * to tell the autofs mount about the new kernel pipe fd. In
+ * order to protect mounts against incorrectly setting the
+ * pipefd we also require that the autofs mount be catatonic.
+ *
+ * This also sets the process group id used to identify the
+ * controlling process (eg. the owning automount(8) daemon).
+ */
+static int autofs_dev_ioctl_setpipefd(struct file *fp,
+				      struct autofs_sb_info *sbi,
+				      struct autofs_dev_ioctl *param)
+{
+	int pipefd;
+	int err = 0;
+	struct pid *new_pid = NULL;
+
+	if (param->setpipefd.pipefd == -1)
+		return -EINVAL;
+
+	pipefd = param->setpipefd.pipefd;
+
+	mutex_lock(&sbi->wq_mutex);
+	if (!sbi->catatonic) {
+		mutex_unlock(&sbi->wq_mutex);
+		return -EBUSY;
+	} else {
+		struct file *pipe;
+
+		new_pid = get_task_pid(current, PIDTYPE_PGID);
+
+		if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) {
+			pr_warn("not allowed to change PID namespace\n");
+			err = -EINVAL;
+			goto out;
+		}
+
+		pipe = fget(pipefd);
+		if (!pipe) {
+			err = -EBADF;
+			goto out;
+		}
+		if (autofs_prepare_pipe(pipe) < 0) {
+			err = -EPIPE;
+			fput(pipe);
+			goto out;
+		}
+		swap(sbi->oz_pgrp, new_pid);
+		sbi->pipefd = pipefd;
+		sbi->pipe = pipe;
+		sbi->catatonic = 0;
+	}
+out:
+	put_pid(new_pid);
+	mutex_unlock(&sbi->wq_mutex);
+	return err;
+}
+
+/*
+ * Make the autofs mount point catatonic, no longer responsive to
+ * mount requests. Also closes the kernel pipe file descriptor.
+ */
+static int autofs_dev_ioctl_catatonic(struct file *fp,
+				      struct autofs_sb_info *sbi,
+				      struct autofs_dev_ioctl *param)
+{
+	autofs_catatonic_mode(sbi);
+	return 0;
+}
+
+/* Set the autofs mount timeout */
+static int autofs_dev_ioctl_timeout(struct file *fp,
+				    struct autofs_sb_info *sbi,
+				    struct autofs_dev_ioctl *param)
+{
+	unsigned long timeout;
+
+	timeout = param->timeout.timeout;
+	param->timeout.timeout = sbi->exp_timeout / HZ;
+	sbi->exp_timeout = timeout * HZ;
+	return 0;
+}
+
+/*
+ * Return the uid and gid of the last request for the mount
+ *
+ * When reconstructing an autofs mount tree with active mounts
+ * we need to re-connect to mounts that may have used the original
+ * process uid and gid (or string variations of them) for mount
+ * lookups within the map entry.
+ */
+static int autofs_dev_ioctl_requester(struct file *fp,
+				      struct autofs_sb_info *sbi,
+				      struct autofs_dev_ioctl *param)
+{
+	struct autofs_info *ino;
+	struct path path;
+	dev_t devid;
+	int err = -ENOENT;
+
+	if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	devid = sbi->sb->s_dev;
+
+	param->requester.uid = param->requester.gid = -1;
+
+	err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
+	if (err)
+		goto out;
+
+	ino = autofs_dentry_ino(path.dentry);
+	if (ino) {
+		err = 0;
+		autofs_expire_wait(&path, 0);
+		spin_lock(&sbi->fs_lock);
+		param->requester.uid =
+			from_kuid_munged(current_user_ns(), ino->uid);
+		param->requester.gid =
+			from_kgid_munged(current_user_ns(), ino->gid);
+		spin_unlock(&sbi->fs_lock);
+	}
+	path_put(&path);
+out:
+	return err;
+}
+
+/*
+ * Call repeatedly until it returns -EAGAIN, meaning there's nothing
+ * more that can be done.
+ */
+static int autofs_dev_ioctl_expire(struct file *fp,
+				   struct autofs_sb_info *sbi,
+				   struct autofs_dev_ioctl *param)
+{
+	struct vfsmount *mnt;
+	int how;
+
+	how = param->expire.how;
+	mnt = fp->f_path.mnt;
+
+	return autofs_do_expire_multi(sbi->sb, mnt, sbi, how);
+}
+
+/* Check if autofs mount point is in use */
+static int autofs_dev_ioctl_askumount(struct file *fp,
+				      struct autofs_sb_info *sbi,
+				      struct autofs_dev_ioctl *param)
+{
+	param->askumount.may_umount = 0;
+	if (may_umount(fp->f_path.mnt))
+		param->askumount.may_umount = 1;
+	return 0;
+}
+
+/*
+ * Check if the given path is a mountpoint.
+ *
+ * If we are supplied with the file descriptor of an autofs
+ * mount we're looking for a specific mount. In this case
+ * the path is considered a mountpoint if it is itself a
+ * mountpoint or contains a mount, such as a multi-mount
+ * without a root mount. In this case we return 1 if the
+ * path is a mount point and the super magic of the covering
+ * mount if there is one or 0 if it isn't a mountpoint.
+ *
+ * If we aren't supplied with a file descriptor then we
+ * lookup the path and check if it is the root of a mount.
+ * If a type is given we are looking for a particular autofs
+ * mount and if we don't find a match we return fail. If the
+ * located path is the root of a mount we return 1 along with
+ * the super magic of the mount or 0 otherwise.
+ *
+ * In both cases the the device number (as returned by
+ * new_encode_dev()) is also returned.
+ */
+static int autofs_dev_ioctl_ismountpoint(struct file *fp,
+					 struct autofs_sb_info *sbi,
+					 struct autofs_dev_ioctl *param)
+{
+	struct path path;
+	const char *name;
+	unsigned int type;
+	unsigned int devid, magic;
+	int err = -ENOENT;
+
+	if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	name = param->path;
+	type = param->ismountpoint.in.type;
+
+	param->ismountpoint.out.devid = devid = 0;
+	param->ismountpoint.out.magic = magic = 0;
+
+	if (!fp || param->ioctlfd == -1) {
+		if (autofs_type_any(type))
+			err = kern_path_mountpoint(AT_FDCWD,
+						   name, &path, LOOKUP_FOLLOW);
+		else
+			err = find_autofs_mount(name, &path,
+						test_by_type, &type);
+		if (err)
+			goto out;
+		devid = new_encode_dev(path.dentry->d_sb->s_dev);
+		err = 0;
+		if (path.mnt->mnt_root == path.dentry) {
+			err = 1;
+			magic = path.dentry->d_sb->s_magic;
+		}
+	} else {
+		dev_t dev = sbi->sb->s_dev;
+
+		err = find_autofs_mount(name, &path, test_by_dev, &dev);
+		if (err)
+			goto out;
+
+		devid = new_encode_dev(dev);
+
+		err = path_has_submounts(&path);
+
+		if (follow_down_one(&path))
+			magic = path.dentry->d_sb->s_magic;
+	}
+
+	param->ismountpoint.out.devid = devid;
+	param->ismountpoint.out.magic = magic;
+	path_put(&path);
+out:
+	return err;
+}
+
+/*
+ * Our range of ioctl numbers isn't 0 based so we need to shift
+ * the array index by _IOC_NR(AUTOFS_CTL_IOC_FIRST) for the table
+ * lookup.
+ */
+#define cmd_idx(cmd)	(cmd - _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST))
+
+static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
+{
+	static ioctl_fn _ioctls[] = {
+		autofs_dev_ioctl_version,
+		autofs_dev_ioctl_protover,
+		autofs_dev_ioctl_protosubver,
+		autofs_dev_ioctl_openmount,
+		autofs_dev_ioctl_closemount,
+		autofs_dev_ioctl_ready,
+		autofs_dev_ioctl_fail,
+		autofs_dev_ioctl_setpipefd,
+		autofs_dev_ioctl_catatonic,
+		autofs_dev_ioctl_timeout,
+		autofs_dev_ioctl_requester,
+		autofs_dev_ioctl_expire,
+		autofs_dev_ioctl_askumount,
+		autofs_dev_ioctl_ismountpoint,
+	};
+	unsigned int idx = cmd_idx(cmd);
+
+	return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx];
+}
+
+/* ioctl dispatcher */
+static int _autofs_dev_ioctl(unsigned int command,
+			     struct autofs_dev_ioctl __user *user)
+{
+	struct autofs_dev_ioctl *param;
+	struct file *fp;
+	struct autofs_sb_info *sbi;
+	unsigned int cmd_first, cmd;
+	ioctl_fn fn = NULL;
+	int err = 0;
+
+	cmd_first = _IOC_NR(AUTOFS_DEV_IOCTL_IOC_FIRST);
+	cmd = _IOC_NR(command);
+
+	if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
+	    cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) {
+		return -ENOTTY;
+	}
+
+	/* Only root can use ioctls other than AUTOFS_DEV_IOCTL_VERSION_CMD
+	 * and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD
+	 */
+	if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
+	    cmd != AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD &&
+	    !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	/* Copy the parameters into kernel space. */
+	param = copy_dev_ioctl(user);
+	if (IS_ERR(param))
+		return PTR_ERR(param);
+
+	err = validate_dev_ioctl(command, param);
+	if (err)
+		goto out;
+
+	fn = lookup_dev_ioctl(cmd);
+	if (!fn) {
+		pr_warn("unknown command 0x%08x\n", command);
+		err = -ENOTTY;
+		goto out;
+	}
+
+	fp = NULL;
+	sbi = NULL;
+
+	/*
+	 * For obvious reasons the openmount can't have a file
+	 * descriptor yet. We don't take a reference to the
+	 * file during close to allow for immediate release,
+	 * and the same for retrieving ioctl version.
+	 */
+	if (cmd != AUTOFS_DEV_IOCTL_VERSION_CMD &&
+	    cmd != AUTOFS_DEV_IOCTL_OPENMOUNT_CMD &&
+	    cmd != AUTOFS_DEV_IOCTL_CLOSEMOUNT_CMD) {
+		fp = fget(param->ioctlfd);
+		if (!fp) {
+			if (cmd == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
+				goto cont;
+			err = -EBADF;
+			goto out;
+		}
+
+		sbi = autofs_dev_ioctl_sbi(fp);
+		if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
+			err = -EINVAL;
+			fput(fp);
+			goto out;
+		}
+
+		/*
+		 * Admin needs to be able to set the mount catatonic in
+		 * order to be able to perform the re-open.
+		 */
+		if (!autofs_oz_mode(sbi) &&
+		    cmd != AUTOFS_DEV_IOCTL_CATATONIC_CMD) {
+			err = -EACCES;
+			fput(fp);
+			goto out;
+		}
+	}
+cont:
+	err = fn(fp, sbi, param);
+
+	if (fp)
+		fput(fp);
+	if (err >= 0 && copy_to_user(user, param, AUTOFS_DEV_IOCTL_SIZE))
+		err = -EFAULT;
+out:
+	free_dev_ioctl(param);
+	return err;
+}
+
+static long autofs_dev_ioctl(struct file *file, unsigned int command,
+			     unsigned long u)
+{
+	int err;
+
+	err = _autofs_dev_ioctl(command, (struct autofs_dev_ioctl __user *) u);
+	return (long) err;
+}
+
+#ifdef CONFIG_COMPAT
+static long autofs_dev_ioctl_compat(struct file *file, unsigned int command,
+				    unsigned long u)
+{
+	return autofs_dev_ioctl(file, command, (unsigned long) compat_ptr(u));
+}
+#else
+#define autofs_dev_ioctl_compat NULL
+#endif
+
+static const struct file_operations _dev_ioctl_fops = {
+	.unlocked_ioctl	 = autofs_dev_ioctl,
+	.compat_ioctl = autofs_dev_ioctl_compat,
+	.owner	 = THIS_MODULE,
+	.llseek = noop_llseek,
+};
+
+static struct miscdevice _autofs_dev_ioctl_misc = {
+	.minor		= AUTOFS_MINOR,
+	.name		= AUTOFS_DEVICE_NAME,
+	.fops		= &_dev_ioctl_fops,
+	.mode           = 0644,
+};
+
+MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
+MODULE_ALIAS("devname:autofs");
+
+/* Register/deregister misc character device */
+int __init autofs_dev_ioctl_init(void)
+{
+	int r;
+
+	r = misc_register(&_autofs_dev_ioctl_misc);
+	if (r) {
+		pr_err("misc_register failed for control device\n");
+		return r;
+	}
+
+	return 0;
+}
+
+void autofs_dev_ioctl_exit(void)
+{
+	misc_deregister(&_autofs_dev_ioctl_misc);
+}

fs/autofs/expire.c

+/*
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
+ * 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 "autofs_i.h"
+
+static unsigned long now;
+
+/* Check if a dentry can be expired */
+static inline int autofs_can_expire(struct dentry *dentry,
+				    unsigned long timeout, int do_now)
+{
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+
+	/* dentry in the process of being deleted */
+	if (ino == NULL)
+		return 0;
+
+	if (!do_now) {
+		/* Too young to die */
+		if (!timeout || time_after(ino->last_used + timeout, now))
+			return 0;
+	}
+	return 1;
+}
+
+/* Check a mount point for busyness */
+static int autofs_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
+{
+	struct dentry *top = dentry;
+	struct path path = {.mnt = mnt, .dentry = dentry};
+	int status = 1;
+
+	pr_debug("dentry %p %pd\n", dentry, dentry);
+
+	path_get(&path);
+
+	if (!follow_down_one(&path))
+		goto done;
+
+	if (is_autofs_dentry(path.dentry)) {
+		struct autofs_sb_info *sbi = autofs_sbi(path.dentry->d_sb);
+
+		/* This is an autofs submount, we can't expire it */
+		if (autofs_type_indirect(sbi->type))
+			goto done;
+	}
+
+	/* Update the expiry counter if fs is busy */
+	if (!may_umount_tree(path.mnt)) {
+		struct autofs_info *ino;
+
+		ino = autofs_dentry_ino(top);
+		ino->last_used = jiffies;
+		goto done;
+	}
+
+	status = 0;
+done:
+	pr_debug("returning = %d\n", status);
+	path_put(&path);
+	return status;
+}
+
+/*
+ * Calculate and dget next entry in the subdirs list under root.
+ */
+static struct dentry *get_next_positive_subdir(struct dentry *prev,
+					       struct dentry *root)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
+	struct list_head *next;
+	struct dentry *q;
+
+	spin_lock(&sbi->lookup_lock);
+	spin_lock(&root->d_lock);
+
+	if (prev)
+		next = prev->d_child.next;
+	else {
+		prev = dget_dlock(root);
+		next = prev->d_subdirs.next;
+	}
+
+cont:
+	if (next == &root->d_subdirs) {
+		spin_unlock(&root->d_lock);
+		spin_unlock(&sbi->lookup_lock);
+		dput(prev);
+		return NULL;
+	}
+
+	q = list_entry(next, struct dentry, d_child);
+
+	spin_lock_nested(&q->d_lock, DENTRY_D_LOCK_NESTED);
+	/* Already gone or negative dentry (under construction) - try next */
+	if (!d_count(q) || !simple_positive(q)) {
+		spin_unlock(&q->d_lock);
+		next = q->d_child.next;
+		goto cont;
+	}
+	dget_dlock(q);
+	spin_unlock(&q->d_lock);
+	spin_unlock(&root->d_lock);
+	spin_unlock(&sbi->lookup_lock);
+
+	dput(prev);
+
+	return q;
+}
+
+/*
+ * Calculate and dget next entry in top down tree traversal.
+ */
+static struct dentry *get_next_positive_dentry(struct dentry *prev,
+					       struct dentry *root)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
+	struct list_head *next;
+	struct dentry *p, *ret;
+
+	if (prev == NULL)
+		return dget(root);
+
+	spin_lock(&sbi->lookup_lock);
+relock:
+	p = prev;
+	spin_lock(&p->d_lock);
+again:
+	next = p->d_subdirs.next;
+	if (next == &p->d_subdirs) {
+		while (1) {
+			struct dentry *parent;
+
+			if (p == root) {
+				spin_unlock(&p->d_lock);
+				spin_unlock(&sbi->lookup_lock);
+				dput(prev);
+				return NULL;
+			}
+
+			parent = p->d_parent;
+			if (!spin_trylock(&parent->d_lock)) {
+				spin_unlock(&p->d_lock);
+				cpu_relax();
+				goto relock;
+			}
+			spin_unlock(&p->d_lock);
+			next = p->d_child.next;
+			p = parent;
+			if (next != &parent->d_subdirs)
+				break;
+		}
+	}
+	ret = list_entry(next, struct dentry, d_child);
+
+	spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
+	/* Negative dentry - try next */
+	if (!simple_positive(ret)) {
+		spin_unlock(&p->d_lock);
+		lock_set_subclass(&ret->d_lock.dep_map, 0, _RET_IP_);
+		p = ret;
+		goto again;
+	}
+	dget_dlock(ret);
+	spin_unlock(&ret->d_lock);
+	spin_unlock(&p->d_lock);
+	spin_unlock(&sbi->lookup_lock);
+
+	dput(prev);
+
+	return ret;
+}
+
+/*
+ * Check a direct mount point for busyness.
+ * Direct mounts have similar expiry semantics to tree mounts.
+ * The tree is not busy iff no mountpoints are busy and there are no
+ * autofs submounts.
+ */
+static int autofs_direct_busy(struct vfsmount *mnt,
+			      struct dentry *top,
+			      unsigned long timeout,
+			      int do_now)
+{
+	pr_debug("top %p %pd\n", top, top);
+
+	/* If it's busy update the expiry counters */
+	if (!may_umount_tree(mnt)) {
+		struct autofs_info *ino;
+
+		ino = autofs_dentry_ino(top);
+		if (ino)
+			ino->last_used = jiffies;
+		return 1;
+	}
+
+	/* Timeout of a direct mount is determined by its top dentry */
+	if (!autofs_can_expire(top, timeout, do_now))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * Check a directory tree of mount points for busyness
+ * The tree is not busy iff no mountpoints are busy
+ */
+static int autofs_tree_busy(struct vfsmount *mnt,
+			    struct dentry *top,
+			    unsigned long timeout,
+			    int do_now)
+{
+	struct autofs_info *top_ino = autofs_dentry_ino(top);
+	struct dentry *p;
+
+	pr_debug("top %p %pd\n", top, top);
+
+	/* Negative dentry - give up */
+	if (!simple_positive(top))
+		return 1;
+
+	p = NULL;
+	while ((p = get_next_positive_dentry(p, top))) {
+		pr_debug("dentry %p %pd\n", p, p);
+
+		/*
+		 * Is someone visiting anywhere in the subtree ?
+		 * If there's no mount we need to check the usage
+		 * count for the autofs dentry.
+		 * If the fs is busy update the expiry counter.
+		 */
+		if (d_mountpoint(p)) {
+			if (autofs_mount_busy(mnt, p)) {
+				top_ino->last_used = jiffies;
+				dput(p);
+				return 1;
+			}
+		} else {
+			struct autofs_info *ino = autofs_dentry_ino(p);
+			unsigned int ino_count = atomic_read(&ino->count);
+
+			/* allow for dget above and top is already dgot */
+			if (p == top)
+				ino_count += 2;
+			else
+				ino_count++;
+
+			if (d_count(p) > ino_count) {
+				top_ino->last_used = jiffies;
+				dput(p);
+				return 1;
+			}
+		}
+	}
+
+	/* Timeout of a tree mount is ultimately determined by its top dentry */
+	if (!autofs_can_expire(top, timeout, do_now))
+		return 1;
+
+	return 0;
+}
+
+static struct dentry *autofs_check_leaves(struct vfsmount *mnt,
+					  struct dentry *parent,
+					  unsigned long timeout,
+					  int do_now)
+{
+	struct dentry *p;
+
+	pr_debug("parent %p %pd\n", parent, parent);
+
+	p = NULL;
+	while ((p = get_next_positive_dentry(p, parent))) {
+		pr_debug("dentry %p %pd\n", p, p);
+
+		if (d_mountpoint(p)) {
+			/* Can we umount this guy */
+			if (autofs_mount_busy(mnt, p))
+				continue;
+
+			/* Can we expire this guy */
+			if (autofs_can_expire(p, timeout, do_now))
+				return p;
+		}
+	}
+	return NULL;
+}
+
+/* Check if we can expire a direct mount (possibly a tree) */
+struct dentry *autofs_expire_direct(struct super_block *sb,
+				    struct vfsmount *mnt,
+				    struct autofs_sb_info *sbi,
+				    int how)
+{
+	unsigned long timeout;
+	struct dentry *root = dget(sb->s_root);
+	int do_now = how & AUTOFS_EXP_IMMEDIATE;
+	struct autofs_info *ino;
+
+	if (!root)
+		return NULL;
+
+	now = jiffies;
+	timeout = sbi->exp_timeout;
+
+	if (!autofs_direct_busy(mnt, root, timeout, do_now)) {
+		spin_lock(&sbi->fs_lock);
+		ino = autofs_dentry_ino(root);
+		/* No point expiring a pending mount */
+		if (ino->flags & AUTOFS_INF_PENDING) {
+			spin_unlock(&sbi->fs_lock);
+			goto out;
+		}
+		ino->flags |= AUTOFS_INF_WANT_EXPIRE;
+		spin_unlock(&sbi->fs_lock);
+		synchronize_rcu();
+		if (!autofs_direct_busy(mnt, root, timeout, do_now)) {
+			spin_lock(&sbi->fs_lock);
+			ino->flags |= AUTOFS_INF_EXPIRING;
+			init_completion(&ino->expire_complete);
+			spin_unlock(&sbi->fs_lock);
+			return root;
+		}
+		spin_lock(&sbi->fs_lock);
+		ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
+		spin_unlock(&sbi->fs_lock);
+	}
+out:
+	dput(root);
+
+	return NULL;
+}
+
+/* Check if 'dentry' should expire, or return a nearby
+ * dentry that is suitable.
+ * If returned dentry is different from arg dentry,
+ * then a dget() reference was taken, else not.
+ */
+static struct dentry *should_expire(struct dentry *dentry,
+				    struct vfsmount *mnt,
+				    unsigned long timeout,
+				    int how)
+{
+	int do_now = how & AUTOFS_EXP_IMMEDIATE;
+	int exp_leaves = how & AUTOFS_EXP_LEAVES;
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	unsigned int ino_count;
+
+	/* No point expiring a pending mount */
+	if (ino->flags & AUTOFS_INF_PENDING)
+		return NULL;
+
+	/*
+	 * Case 1: (i) indirect mount or top level pseudo direct mount
+	 *	   (autofs-4.1).
+	 *	   (ii) indirect mount with offset mount, check the "/"
+	 *	   offset (autofs-5.0+).
+	 */
+	if (d_mountpoint(dentry)) {
+		pr_debug("checking mountpoint %p %pd\n", dentry, dentry);
+
+		/* Can we umount this guy */
+		if (autofs_mount_busy(mnt, dentry))
+			return NULL;
+
+		/* Can we expire this guy */
+		if (autofs_can_expire(dentry, timeout, do_now))
+			return dentry;
+		return NULL;
+	}
+
+	if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
+		pr_debug("checking symlink %p %pd\n", dentry, dentry);
+		/*
+		 * A symlink can't be "busy" in the usual sense so
+		 * just check last used for expire timeout.
+		 */
+		if (autofs_can_expire(dentry, timeout, do_now))
+			return dentry;
+		return NULL;
+	}
+
+	if (simple_empty(dentry))
+		return NULL;
+
+	/* Case 2: tree mount, expire iff entire tree is not busy */
+	if (!exp_leaves) {
+		/* Path walk currently on this dentry? */
+		ino_count = atomic_read(&ino->count) + 1;
+		if (d_count(dentry) > ino_count)
+			return NULL;
+
+		if (!autofs_tree_busy(mnt, dentry, timeout, do_now))
+			return dentry;
+	/*
+	 * Case 3: pseudo direct mount, expire individual leaves
+	 *	   (autofs-4.1).
+	 */
+	} else {
+		/* Path walk currently on this dentry? */
+		struct dentry *expired;
+
+		ino_count = atomic_read(&ino->count) + 1;
+		if (d_count(dentry) > ino_count)
+			return NULL;
+
+		expired = autofs_check_leaves(mnt, dentry, timeout, do_now);
+		if (expired) {
+			if (expired == dentry)
+				dput(dentry);
+			return expired;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * Find an eligible tree to time-out
+ * A tree is eligible if :-
+ *  - it is unused by any user process
+ *  - it has been unused for exp_timeout time
+ */
+struct dentry *autofs_expire_indirect(struct super_block *sb,
+				      struct vfsmount *mnt,
+				      struct autofs_sb_info *sbi,
+				      int how)
+{
+	unsigned long timeout;
+	struct dentry *root = sb->s_root;
+	struct dentry *dentry;
+	struct dentry *expired;
+	struct dentry *found;
+	struct autofs_info *ino;
+
+	if (!root)
+		return NULL;
+
+	now = jiffies;
+	timeout = sbi->exp_timeout;
+
+	dentry = NULL;
+	while ((dentry = get_next_positive_subdir(dentry, root))) {
+		int flags = how;
+
+		spin_lock(&sbi->fs_lock);
+		ino = autofs_dentry_ino(dentry);
+		if (ino->flags & AUTOFS_INF_WANT_EXPIRE) {
+			spin_unlock(&sbi->fs_lock);
+			continue;
+		}
+		spin_unlock(&sbi->fs_lock);
+
+		expired = should_expire(dentry, mnt, timeout, flags);
+		if (!expired)
+			continue;
+
+		spin_lock(&sbi->fs_lock);
+		ino = autofs_dentry_ino(expired);
+		ino->flags |= AUTOFS_INF_WANT_EXPIRE;
+		spin_unlock(&sbi->fs_lock);
+		synchronize_rcu();
+
+		/* Make sure a reference is not taken on found if
+		 * things have changed.
+		 */
+		flags &= ~AUTOFS_EXP_LEAVES;
+		found = should_expire(expired, mnt, timeout, how);
+		if (!found || found != expired)
+			/* Something has changed, continue */
+			goto next;
+
+		if (expired != dentry)
+			dput(dentry);
+
+		spin_lock(&sbi->fs_lock);
+		goto found;
+next:
+		spin_lock(&sbi->fs_lock);
+		ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
+		spin_unlock(&sbi->fs_lock);
+		if (expired != dentry)
+			dput(expired);
+	}
+	return NULL;
+
+found:
+	pr_debug("returning %p %pd\n", expired, expired);
+	ino->flags |= AUTOFS_INF_EXPIRING;
+	init_completion(&ino->expire_complete);
+	spin_unlock(&sbi->fs_lock);
+	return expired;
+}
+
+int autofs_expire_wait(const struct path *path, int rcu_walk)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	int status;
+	int state;
+
+	/* Block on any pending expire */
+	if (!(ino->flags & AUTOFS_INF_WANT_EXPIRE))
+		return 0;
+	if (rcu_walk)
+		return -ECHILD;
+
+retry:
+	spin_lock(&sbi->fs_lock);
+	state = ino->flags & (AUTOFS_INF_WANT_EXPIRE | AUTOFS_INF_EXPIRING);
+	if (state == AUTOFS_INF_WANT_EXPIRE) {
+		spin_unlock(&sbi->fs_lock);
+		/*
+		 * Possibly being selected for expire, wait until
+		 * it's selected or not.
+		 */
+		schedule_timeout_uninterruptible(HZ/10);
+		goto retry;
+	}
+	if (state & AUTOFS_INF_EXPIRING) {
+		spin_unlock(&sbi->fs_lock);
+
+		pr_debug("waiting for expire %p name=%pd\n", dentry, dentry);
+
+		status = autofs_wait(sbi, path, NFY_NONE);
+		wait_for_completion(&ino->expire_complete);
+
+		pr_debug("expire done status=%d\n", status);
+
+		if (d_unhashed(dentry))
+			return -EAGAIN;
+
+		return status;
+	}
+	spin_unlock(&sbi->fs_lock);
+
+	return 0;
+}
+
+/* Perform an expiry operation */
+int autofs_expire_run(struct super_block *sb,
+		      struct vfsmount *mnt,
+		      struct autofs_sb_info *sbi,
+		      struct autofs_packet_expire __user *pkt_p)
+{
+	struct autofs_packet_expire pkt;
+	struct autofs_info *ino;
+	struct dentry *dentry;
+	int ret = 0;
+
+	memset(&pkt, 0, sizeof(pkt));
+
+	pkt.hdr.proto_version = sbi->version;
+	pkt.hdr.type = autofs_ptype_expire;
+
+	dentry = autofs_expire_indirect(sb, mnt, sbi, 0);
+	if (!dentry)
+		return -EAGAIN;
+
+	pkt.len = dentry->d_name.len;
+	memcpy(pkt.name, dentry->d_name.name, pkt.len);
+	pkt.name[pkt.len] = '\0';
+	dput(dentry);
+
+	if (copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)))
+		ret = -EFAULT;
+
+	spin_lock(&sbi->fs_lock);
+	ino = autofs_dentry_ino(dentry);
+	/* avoid rapid-fire expire attempts if expiry fails */
+	ino->last_used = now;
+	ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE);
+	complete_all(&ino->expire_complete);
+	spin_unlock(&sbi->fs_lock);
+
+	return ret;
+}
+
+int autofs_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+			   struct autofs_sb_info *sbi, int when)
+{
+	struct dentry *dentry;
+	int ret = -EAGAIN;
+
+	if (autofs_type_trigger(sbi->type))
+		dentry = autofs_expire_direct(sb, mnt, sbi, when);
+	else
+		dentry = autofs_expire_indirect(sb, mnt, sbi, when);
+
+	if (dentry) {
+		struct autofs_info *ino = autofs_dentry_ino(dentry);
+		const struct path path = { .mnt = mnt, .dentry = dentry };
+
+		/* This is synchronous because it makes the daemon a
+		 * little easier
+		 */
+		ret = autofs_wait(sbi, &path, NFY_EXPIRE);
+
+		spin_lock(&sbi->fs_lock);
+		/* avoid rapid-fire expire attempts if expiry fails */
+		ino->last_used = now;
+		ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE);
+		complete_all(&ino->expire_complete);
+		spin_unlock(&sbi->fs_lock);
+		dput(dentry);
+	}
+
+	return ret;
+}
+
+/*
+ * Call repeatedly until it returns -EAGAIN, meaning there's nothing
+ * more to be done.
+ */
+int autofs_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+			struct autofs_sb_info *sbi, int __user *arg)
+{
+	int do_now = 0;
+
+	if (arg && get_user(do_now, arg))
+		return -EFAULT;
+
+	return autofs_do_expire_multi(sb, mnt, sbi, do_now);
+}

fs/autofs/init.c

+/*
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include "autofs_i.h"
+
+static struct dentry *autofs_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_nodev(fs_type, flags, data, autofs_fill_super);
+}
+
+static struct file_system_type autofs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "autofs",
+	.mount		= autofs_mount,
+	.kill_sb	= autofs_kill_sb,
+};
+MODULE_ALIAS_FS("autofs");
+
+static int __init init_autofs_fs(void)
+{
+	int err;
+
+	autofs_dev_ioctl_init();
+
+	err = register_filesystem(&autofs_fs_type);
+	if (err)
+		autofs_dev_ioctl_exit();
+
+	return err;
+}
+
+static void __exit exit_autofs_fs(void)
+{
+	autofs_dev_ioctl_exit();
+	unregister_filesystem(&autofs_fs_type);
+}
+
+module_init(init_autofs_fs)
+module_exit(exit_autofs_fs)
+MODULE_LICENSE("GPL");

fs/autofs/inode.c

+/*
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ * Copyright 2005-2006 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/kernel.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/seq_file.h>
+#include <linux/pagemap.h>
+#include <linux/parser.h>
+#include <linux/bitops.h>
+#include <linux/magic.h>
+#include "autofs_i.h"
+#include <linux/module.h>
+
+struct autofs_info *autofs_new_ino(struct autofs_sb_info *sbi)
+{
+	struct autofs_info *ino;
+
+	ino = kzalloc(sizeof(*ino), GFP_KERNEL);
+	if (ino) {
+		INIT_LIST_HEAD(&ino->active);
+		INIT_LIST_HEAD(&ino->expiring);
+		ino->last_used = jiffies;
+		ino->sbi = sbi;
+	}
+	return ino;
+}
+
+void autofs_clean_ino(struct autofs_info *ino)
+{
+	ino->uid = GLOBAL_ROOT_UID;
+	ino->gid = GLOBAL_ROOT_GID;
+	ino->last_used = jiffies;
+}
+
+void autofs_free_ino(struct autofs_info *ino)
+{
+	kfree(ino);
+}
+
+void autofs_kill_sb(struct super_block *sb)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(sb);
+
+	/*
+	 * In the event of a failure in get_sb_nodev the superblock
+	 * info is not present so nothing else has been setup, so
+	 * just call kill_anon_super when we are called from
+	 * deactivate_super.
+	 */
+	if (sbi) {
+		/* Free wait queues, close pipe */
+		autofs_catatonic_mode(sbi);
+		put_pid(sbi->oz_pgrp);
+	}
+
+	pr_debug("shutting down\n");
+	kill_litter_super(sb);
+	if (sbi)
+		kfree_rcu(sbi, rcu);
+}
+
+static int autofs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(root->d_sb);
+	struct inode *root_inode = d_inode(root->d_sb->s_root);
+
+	if (!sbi)
+		return 0;
+
+	seq_printf(m, ",fd=%d", sbi->pipefd);
+	if (!uid_eq(root_inode->i_uid, GLOBAL_ROOT_UID))
+		seq_printf(m, ",uid=%u",
+			from_kuid_munged(&init_user_ns, root_inode->i_uid));
+	if (!gid_eq(root_inode->i_gid, GLOBAL_ROOT_GID))
+		seq_printf(m, ",gid=%u",
+			from_kgid_munged(&init_user_ns, root_inode->i_gid));
+	seq_printf(m, ",pgrp=%d", pid_vnr(sbi->oz_pgrp));
+	seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
+	seq_printf(m, ",minproto=%d", sbi->min_proto);
+	seq_printf(m, ",maxproto=%d", sbi->max_proto);
+
+	if (autofs_type_offset(sbi->type))
+		seq_printf(m, ",offset");
+	else if (autofs_type_direct(sbi->type))
+		seq_printf(m, ",direct");
+	else
+		seq_printf(m, ",indirect");
+#ifdef CONFIG_CHECKPOINT_RESTORE
+	if (sbi->pipe)
+		seq_printf(m, ",pipe_ino=%ld", file_inode(sbi->pipe)->i_ino);
+	else
+		seq_printf(m, ",pipe_ino=-1");
+#endif
+	return 0;
+}
+
+static void autofs_evict_inode(struct inode *inode)
+{
+	clear_inode(inode);
+	kfree(inode->i_private);
+}
+
+static const struct super_operations autofs_sops = {
+	.statfs		= simple_statfs,
+	.show_options	= autofs_show_options,
+	.evict_inode	= autofs_evict_inode,
+};
+
+enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
+	Opt_indirect, Opt_direct, Opt_offset};
+
+static const match_table_t tokens = {
+	{Opt_fd, "fd=%u"},
+	{Opt_uid, "uid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_pgrp, "pgrp=%u"},
+	{Opt_minproto, "minproto=%u"},
+	{Opt_maxproto, "maxproto=%u"},
+	{Opt_indirect, "indirect"},
+	{Opt_direct, "direct"},
+	{Opt_offset, "offset"},
+	{Opt_err, NULL}
+};
+
+static int parse_options(char *options, int *pipefd, kuid_t *uid, kgid_t *gid,
+			 int *pgrp, bool *pgrp_set, unsigned int *type,
+			 int *minproto, int *maxproto)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+
+	*uid = current_uid();
+	*gid = current_gid();
+
+	*minproto = AUTOFS_MIN_PROTO_VERSION;
+	*maxproto = AUTOFS_MAX_PROTO_VERSION;
+
+	*pipefd = -1;
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_fd:
+			if (match_int(args, pipefd))
+				return 1;
+			break;
+		case Opt_uid:
+			if (match_int(args, &option))
+				return 1;
+			*uid = make_kuid(current_user_ns(), option);
+			if (!uid_valid(*uid))
+				return 1;
+			break;
+		case Opt_gid:
+			if (match_int(args, &option))
+				return 1;
+			*gid = make_kgid(current_user_ns(), option);
+			if (!gid_valid(*gid))
+				return 1;
+			break;
+		case Opt_pgrp:
+			if (match_int(args, &option))
+				return 1;
+			*pgrp = option;
+			*pgrp_set = true;
+			break;
+		case Opt_minproto:
+			if (match_int(args, &option))
+				return 1;
+			*minproto = option;
+			break;
+		case Opt_maxproto:
+			if (match_int(args, &option))
+				return 1;
+			*maxproto = option;
+			break;
+		case Opt_indirect:
+			set_autofs_type_indirect(type);
+			break;
+		case Opt_direct:
+			set_autofs_type_direct(type);
+			break;
+		case Opt_offset:
+			set_autofs_type_offset(type);
+			break;
+		default:
+			return 1;
+		}
+	}
+	return (*pipefd < 0);
+}
+
+int autofs_fill_super(struct super_block *s, void *data, int silent)
+{
+	struct inode *root_inode;
+	struct dentry *root;
+	struct file *pipe;
+	int pipefd;
+	struct autofs_sb_info *sbi;
+	struct autofs_info *ino;
+	int pgrp = 0;
+	bool pgrp_set = false;
+	int ret = -EINVAL;
+
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+	pr_debug("starting up, sbi = %p\n", sbi);
+
+	s->s_fs_info = sbi;
+	sbi->magic = AUTOFS_SBI_MAGIC;
+	sbi->pipefd = -1;
+	sbi->pipe = NULL;
+	sbi->catatonic = 1;
+	sbi->exp_timeout = 0;
+	sbi->oz_pgrp = NULL;
+	sbi->sb = s;
+	sbi->version = 0;
+	sbi->sub_version = 0;
+	set_autofs_type_indirect(&sbi->type);
+	sbi->min_proto = 0;
+	sbi->max_proto = 0;
+	mutex_init(&sbi->wq_mutex);
+	mutex_init(&sbi->pipe_mutex);
+	spin_lock_init(&sbi->fs_lock);
+	sbi->queues = NULL;
+	spin_lock_init(&sbi->lookup_lock);
+	INIT_LIST_HEAD(&sbi->active_list);
+	INIT_LIST_HEAD(&sbi->expiring_list);
+	s->s_blocksize = 1024;
+	s->s_blocksize_bits = 10;
+	s->s_magic = AUTOFS_SUPER_MAGIC;
+	s->s_op = &autofs_sops;
+	s->s_d_op = &autofs_dentry_operations;
+	s->s_time_gran = 1;
+
+	/*
+	 * Get the root inode and dentry, but defer checking for errors.
+	 */
+	ino = autofs_new_ino(sbi);
+	if (!ino) {
+		ret = -ENOMEM;
+		goto fail_free;
+	}
+	root_inode = autofs_get_inode(s, S_IFDIR | 0755);
+	root = d_make_root(root_inode);
+	if (!root)
+		goto fail_ino;
+	pipe = NULL;
+
+	root->d_fsdata = ino;
+
+	/* Can this call block? */
+	if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
+			  &pgrp, &pgrp_set, &sbi->type, &sbi->min_proto,
+			  &sbi->max_proto)) {
+		pr_err("called with bogus options\n");
+		goto fail_dput;
+	}
+
+	/* Test versions first */
+	if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
+	    sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
+		pr_err("kernel does not match daemon version "
+		       "daemon (%d, %d) kernel (%d, %d)\n",
+		       sbi->min_proto, sbi->max_proto,
+		       AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
+		goto fail_dput;
+	}
+
+	/* Establish highest kernel protocol version */
+	if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
+		sbi->version = AUTOFS_MAX_PROTO_VERSION;
+	else
+		sbi->version = sbi->max_proto;
+	sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
+
+	if (pgrp_set) {
+		sbi->oz_pgrp = find_get_pid(pgrp);
+		if (!sbi->oz_pgrp) {
+			pr_err("could not find process group %d\n",
+				pgrp);
+			goto fail_dput;
+		}
+	} else {
+		sbi->oz_pgrp = get_task_pid(current, PIDTYPE_PGID);
+	}
+
+	if (autofs_type_trigger(sbi->type))
+		__managed_dentry_set_managed(root);
+
+	root_inode->i_fop = &autofs_root_operations;
+	root_inode->i_op = &autofs_dir_inode_operations;
+
+	pr_debug("pipe fd = %d, pgrp = %u\n", pipefd, pid_nr(sbi->oz_pgrp));
+	pipe = fget(pipefd);
+
+	if (!pipe) {
+		pr_err("could not open pipe file descriptor\n");
+		goto fail_put_pid;
+	}
+	ret = autofs_prepare_pipe(pipe);
+	if (ret < 0)
+		goto fail_fput;
+	sbi->pipe = pipe;
+	sbi->pipefd = pipefd;
+	sbi->catatonic = 0;
+
+	/*
+	 * Success! Install the root dentry now to indicate completion.
+	 */
+	s->s_root = root;
+	return 0;
+
+	/*
+	 * Failure ... clean up.
+	 */
+fail_fput:
+	pr_err("pipe file descriptor does not contain proper ops\n");
+	fput(pipe);
+fail_put_pid:
+	put_pid(sbi->oz_pgrp);
+fail_dput:
+	dput(root);
+	goto fail_free;
+fail_ino:
+	autofs_free_ino(ino);
+fail_free:
+	kfree(sbi);
+	s->s_fs_info = NULL;
+	return ret;
+}
+
+struct inode *autofs_get_inode(struct super_block *sb, umode_t mode)
+{
+	struct inode *inode = new_inode(sb);
+
+	if (inode == NULL)
+		return NULL;
+
+	inode->i_mode = mode;
+	if (sb->s_root) {
+		inode->i_uid = d_inode(sb->s_root)->i_uid;
+		inode->i_gid = d_inode(sb->s_root)->i_gid;
+	}
+	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+	inode->i_ino = get_next_ino();
+
+	if (S_ISDIR(mode)) {
+		set_nlink(inode, 2);
+		inode->i_op = &autofs_dir_inode_operations;
+		inode->i_fop = &autofs_dir_operations;
+	} else if (S_ISLNK(mode)) {
+		inode->i_op = &autofs_symlink_inode_operations;
+	} else
+		WARN_ON(1);
+
+	return inode;
+}

fs/autofs/root.c

+/*
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
+ * 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/capability.h>
+#include <linux/errno.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/param.h>
+#include <linux/time.h>
+#include <linux/compat.h>
+#include <linux/mutex.h>
+
+#include "autofs_i.h"
+
+static int autofs_dir_symlink(struct inode *, struct dentry *, const char *);
+static int autofs_dir_unlink(struct inode *, struct dentry *);
+static int autofs_dir_rmdir(struct inode *, struct dentry *);
+static int autofs_dir_mkdir(struct inode *, struct dentry *, umode_t);
+static long autofs_root_ioctl(struct file *, unsigned int, unsigned long);
+#ifdef CONFIG_COMPAT
+static long autofs_root_compat_ioctl(struct file *,
+				     unsigned int, unsigned long);
+#endif
+static int autofs_dir_open(struct inode *inode, struct file *file);
+static struct dentry *autofs_lookup(struct inode *,
+				    struct dentry *, unsigned int);
+static struct vfsmount *autofs_d_automount(struct path *);
+static int autofs_d_manage(const struct path *, bool);
+static void autofs_dentry_release(struct dentry *);
+
+const struct file_operations autofs_root_operations = {
+	.open		= dcache_dir_open,
+	.release	= dcache_dir_close,
+	.read		= generic_read_dir,
+	.iterate_shared	= dcache_readdir,
+	.llseek		= dcache_dir_lseek,
+	.unlocked_ioctl	= autofs_root_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= autofs_root_compat_ioctl,
+#endif
+};
+
+const struct file_operations autofs_dir_operations = {
+	.open		= autofs_dir_open,
+	.release	= dcache_dir_close,
+	.read		= generic_read_dir,
+	.iterate_shared	= dcache_readdir,
+	.llseek		= dcache_dir_lseek,
+};
+
+const struct inode_operations autofs_dir_inode_operations = {
+	.lookup		= autofs_lookup,
+	.unlink		= autofs_dir_unlink,
+	.symlink	= autofs_dir_symlink,
+	.mkdir		= autofs_dir_mkdir,
+	.rmdir		= autofs_dir_rmdir,
+};
+
+const struct dentry_operations autofs_dentry_operations = {
+	.d_automount	= autofs_d_automount,
+	.d_manage	= autofs_d_manage,
+	.d_release	= autofs_dentry_release,
+};
+
+static void autofs_add_active(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino;
+
+	ino = autofs_dentry_ino(dentry);
+	if (ino) {
+		spin_lock(&sbi->lookup_lock);
+		if (!ino->active_count) {
+			if (list_empty(&ino->active))
+				list_add(&ino->active, &sbi->active_list);
+		}
+		ino->active_count++;
+		spin_unlock(&sbi->lookup_lock);
+	}
+}
+
+static void autofs_del_active(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino;
+
+	ino = autofs_dentry_ino(dentry);
+	if (ino) {
+		spin_lock(&sbi->lookup_lock);
+		ino->active_count--;
+		if (!ino->active_count) {
+			if (!list_empty(&ino->active))
+				list_del_init(&ino->active);
+		}
+		spin_unlock(&sbi->lookup_lock);
+	}
+}
+
+static int autofs_dir_open(struct inode *inode, struct file *file)
+{
+	struct dentry *dentry = file->f_path.dentry;
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+
+	pr_debug("file=%p dentry=%p %pd\n", file, dentry, dentry);
+
+	if (autofs_oz_mode(sbi))
+		goto out;
+
+	/*
+	 * An empty directory in an autofs file system is always a
+	 * mount point. The daemon must have failed to mount this
+	 * during lookup so it doesn't exist. This can happen, for
+	 * example, if user space returns an incorrect status for a
+	 * mount request. Otherwise we're doing a readdir on the
+	 * autofs file system so just let the libfs routines handle
+	 * it.
+	 */
+	spin_lock(&sbi->lookup_lock);
+	if (!path_is_mountpoint(&file->f_path) && simple_empty(dentry)) {
+		spin_unlock(&sbi->lookup_lock);
+		return -ENOENT;
+	}
+	spin_unlock(&sbi->lookup_lock);
+
+out:
+	return dcache_dir_open(inode, file);
+}
+
+static void autofs_dentry_release(struct dentry *de)
+{
+	struct autofs_info *ino = autofs_dentry_ino(de);
+	struct autofs_sb_info *sbi = autofs_sbi(de->d_sb);
+
+	pr_debug("releasing %p\n", de);
+
+	if (!ino)
+		return;
+
+	if (sbi) {
+		spin_lock(&sbi->lookup_lock);
+		if (!list_empty(&ino->active))
+			list_del(&ino->active);
+		if (!list_empty(&ino->expiring))
+			list_del(&ino->expiring);
+		spin_unlock(&sbi->lookup_lock);
+	}
+
+	autofs_free_ino(ino);
+}
+
+static struct dentry *autofs_lookup_active(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct dentry *parent = dentry->d_parent;
+	const struct qstr *name = &dentry->d_name;
+	unsigned int len = name->len;
+	unsigned int hash = name->hash;
+	const unsigned char *str = name->name;
+	struct list_head *p, *head;
+
+	head = &sbi->active_list;
+	if (list_empty(head))
+		return NULL;
+	spin_lock(&sbi->lookup_lock);
+	list_for_each(p, head) {
+		struct autofs_info *ino;
+		struct dentry *active;
+		const struct qstr *qstr;
+
+		ino = list_entry(p, struct autofs_info, active);
+		active = ino->dentry;
+
+		spin_lock(&active->d_lock);
+
+		/* Already gone? */
+		if ((int) d_count(active) <= 0)
+			goto next;
+
+		qstr = &active->d_name;
+
+		if (active->d_name.hash != hash)
+			goto next;
+		if (active->d_parent != parent)
+			goto next;
+
+		if (qstr->len != len)
+			goto next;
+		if (memcmp(qstr->name, str, len))
+			goto next;
+
+		if (d_unhashed(active)) {
+			dget_dlock(active);
+			spin_unlock(&active->d_lock);
+			spin_unlock(&sbi->lookup_lock);
+			return active;
+		}
+next:
+		spin_unlock(&active->d_lock);
+	}
+	spin_unlock(&sbi->lookup_lock);
+
+	return NULL;
+}
+
+static struct dentry *autofs_lookup_expiring(struct dentry *dentry,
+					     bool rcu_walk)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct dentry *parent = dentry->d_parent;
+	const struct qstr *name = &dentry->d_name;
+	unsigned int len = name->len;
+	unsigned int hash = name->hash;
+	const unsigned char *str = name->name;
+	struct list_head *p, *head;
+
+	head = &sbi->expiring_list;
+	if (list_empty(head))
+		return NULL;
+	spin_lock(&sbi->lookup_lock);
+	list_for_each(p, head) {
+		struct autofs_info *ino;
+		struct dentry *expiring;
+		const struct qstr *qstr;
+
+		if (rcu_walk) {
+			spin_unlock(&sbi->lookup_lock);
+			return ERR_PTR(-ECHILD);
+		}
+
+		ino = list_entry(p, struct autofs_info, expiring);
+		expiring = ino->dentry;
+
+		spin_lock(&expiring->d_lock);
+
+		/* We've already been dentry_iput or unlinked */
+		if (d_really_is_negative(expiring))
+			goto next;
+
+		qstr = &expiring->d_name;
+
+		if (expiring->d_name.hash != hash)
+			goto next;
+		if (expiring->d_parent != parent)
+			goto next;
+
+		if (qstr->len != len)
+			goto next;
+		if (memcmp(qstr->name, str, len))
+			goto next;
+
+		if (d_unhashed(expiring)) {
+			dget_dlock(expiring);
+			spin_unlock(&expiring->d_lock);
+			spin_unlock(&sbi->lookup_lock);
+			return expiring;
+		}
+next:
+		spin_unlock(&expiring->d_lock);
+	}
+	spin_unlock(&sbi->lookup_lock);
+
+	return NULL;
+}
+
+static int autofs_mount_wait(const struct path *path, bool rcu_walk)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(path->dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(path->dentry);
+	int status = 0;
+
+	if (ino->flags & AUTOFS_INF_PENDING) {
+		if (rcu_walk)
+			return -ECHILD;
+		pr_debug("waiting for mount name=%pd\n", path->dentry);
+		status = autofs_wait(sbi, path, NFY_MOUNT);
+		pr_debug("mount wait done status=%d\n", status);
+	}
+	ino->last_used = jiffies;
+	return status;
+}
+
+static int do_expire_wait(const struct path *path, bool rcu_walk)
+{
+	struct dentry *dentry = path->dentry;
+	struct dentry *expiring;
+
+	expiring = autofs_lookup_expiring(dentry, rcu_walk);
+	if (IS_ERR(expiring))
+		return PTR_ERR(expiring);
+	if (!expiring)
+		return autofs_expire_wait(path, rcu_walk);
+	else {
+		const struct path this = { .mnt = path->mnt, .dentry = expiring };
+		/*
+		 * If we are racing with expire the request might not
+		 * be quite complete, but the directory has been removed
+		 * so it must have been successful, just wait for it.
+		 */
+		autofs_expire_wait(&this, 0);
+		autofs_del_expiring(expiring);
+		dput(expiring);
+	}
+	return 0;
+}
+
+static struct dentry *autofs_mountpoint_changed(struct path *path)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+
+	/*
+	 * If this is an indirect mount the dentry could have gone away
+	 * as a result of an expire and a new one created.
+	 */
+	if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
+		struct dentry *parent = dentry->d_parent;
+		struct autofs_info *ino;
+		struct dentry *new;
+
+		new = d_lookup(parent, &dentry->d_name);
+		if (!new)
+			return NULL;
+		ino = autofs_dentry_ino(new);
+		ino->last_used = jiffies;
+		dput(path->dentry);
+		path->dentry = new;
+	}
+	return path->dentry;
+}
+
+static struct vfsmount *autofs_d_automount(struct path *path)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	int status;
+
+	pr_debug("dentry=%p %pd\n", dentry, dentry);
+
+	/* The daemon never triggers a mount. */
+	if (autofs_oz_mode(sbi))
+		return NULL;
+
+	/*
+	 * If an expire request is pending everyone must wait.
+	 * If the expire fails we're still mounted so continue
+	 * the follow and return. A return of -EAGAIN (which only
+	 * happens with indirect mounts) means the expire completed
+	 * and the directory was removed, so just go ahead and try
+	 * the mount.
+	 */
+	status = do_expire_wait(path, 0);
+	if (status && status != -EAGAIN)
+		return NULL;
+
+	/* Callback to the daemon to perform the mount or wait */
+	spin_lock(&sbi->fs_lock);
+	if (ino->flags & AUTOFS_INF_PENDING) {
+		spin_unlock(&sbi->fs_lock);
+		status = autofs_mount_wait(path, 0);
+		if (status)
+			return ERR_PTR(status);
+		goto done;
+	}
+
+	/*
+	 * If the dentry is a symlink it's equivalent to a directory
+	 * having path_is_mountpoint() true, so there's no need to call
+	 * back to the daemon.
+	 */
+	if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
+		spin_unlock(&sbi->fs_lock);
+		goto done;
+	}
+
+	if (!path_is_mountpoint(path)) {
+		/*
+		 * It's possible that user space hasn't removed directories
+		 * after umounting a rootless multi-mount, although it
+		 * should. For v5 path_has_submounts() is sufficient to
+		 * handle this because the leaves of the directory tree under
+		 * the mount never trigger mounts themselves (they have an
+		 * autofs trigger mount mounted on them). But v4 pseudo direct
+		 * mounts do need the leaves to trigger mounts. In this case
+		 * we have no choice but to use the list_empty() check and
+		 * require user space behave.
+		 */
+		if (sbi->version > 4) {
+			if (path_has_submounts(path)) {
+				spin_unlock(&sbi->fs_lock);
+				goto done;
+			}
+		} else {
+			if (!simple_empty(dentry)) {
+				spin_unlock(&sbi->fs_lock);
+				goto done;
+			}
+		}
+		ino->flags |= AUTOFS_INF_PENDING;
+		spin_unlock(&sbi->fs_lock);
+		status = autofs_mount_wait(path, 0);
+		spin_lock(&sbi->fs_lock);
+		ino->flags &= ~AUTOFS_INF_PENDING;
+		if (status) {
+			spin_unlock(&sbi->fs_lock);
+			return ERR_PTR(status);
+		}
+	}
+	spin_unlock(&sbi->fs_lock);
+done:
+	/* Mount succeeded, check if we ended up with a new dentry */
+	dentry = autofs_mountpoint_changed(path);
+	if (!dentry)
+		return ERR_PTR(-ENOENT);
+
+	return NULL;
+}
+
+static int autofs_d_manage(const struct path *path, bool rcu_walk)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	int status;
+
+	pr_debug("dentry=%p %pd\n", dentry, dentry);
+
+	/* The daemon never waits. */
+	if (autofs_oz_mode(sbi)) {
+		if (!path_is_mountpoint(path))
+			return -EISDIR;
+		return 0;
+	}
+
+	/* Wait for pending expires */
+	if (do_expire_wait(path, rcu_walk) == -ECHILD)
+		return -ECHILD;
+
+	/*
+	 * This dentry may be under construction so wait on mount
+	 * completion.
+	 */
+	status = autofs_mount_wait(path, rcu_walk);
+	if (status)
+		return status;
+
+	if (rcu_walk) {
+		/* We don't need fs_lock in rcu_walk mode,
+		 * just testing 'AUTOFS_INFO_NO_RCU' is enough.
+		 * simple_empty() takes a spinlock, so leave it
+		 * to last.
+		 * We only return -EISDIR when certain this isn't
+		 * a mount-trap.
+		 */
+		struct inode *inode;
+
+		if (ino->flags & AUTOFS_INF_WANT_EXPIRE)
+			return 0;
+		if (path_is_mountpoint(path))
+			return 0;
+		inode = d_inode_rcu(dentry);
+		if (inode && S_ISLNK(inode->i_mode))
+			return -EISDIR;
+		if (list_empty(&dentry->d_subdirs))
+			return 0;
+		if (!simple_empty(dentry))
+			return -EISDIR;
+		return 0;
+	}
+
+	spin_lock(&sbi->fs_lock);
+	/*
+	 * If the dentry has been selected for expire while we slept
+	 * on the lock then it might go away. We'll deal with that in
+	 * ->d_automount() and wait on a new mount if the expire
+	 * succeeds or return here if it doesn't (since there's no
+	 * mount to follow with a rootless multi-mount).
+	 */
+	if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
+		/*
+		 * Any needed mounting has been completed and the path
+		 * updated so check if this is a rootless multi-mount so
+		 * we can avoid needless calls ->d_automount() and avoid
+		 * an incorrect ELOOP error return.
+		 */
+		if ((!path_is_mountpoint(path) && !simple_empty(dentry)) ||
+		    (d_really_is_positive(dentry) && d_is_symlink(dentry)))
+			status = -EISDIR;
+	}
+	spin_unlock(&sbi->fs_lock);
+
+	return status;
+}
+
+/* Lookups in the root directory */
+static struct dentry *autofs_lookup(struct inode *dir,
+				    struct dentry *dentry, unsigned int flags)
+{
+	struct autofs_sb_info *sbi;
+	struct autofs_info *ino;
+	struct dentry *active;
+
+	pr_debug("name = %pd\n", dentry);
+
+	/* File name too long to exist */
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	sbi = autofs_sbi(dir->i_sb);
+
+	pr_debug("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
+		 current->pid, task_pgrp_nr(current), sbi->catatonic,
+		 autofs_oz_mode(sbi));
+
+	active = autofs_lookup_active(dentry);
+	if (active)
+		return active;
+	else {
+		/*
+		 * A dentry that is not within the root can never trigger a
+		 * mount operation, unless the directory already exists, so we
+		 * can return fail immediately.  The daemon however does need
+		 * to create directories within the file system.
+		 */
+		if (!autofs_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
+			return ERR_PTR(-ENOENT);
+
+		/* Mark entries in the root as mount triggers */
+		if (IS_ROOT(dentry->d_parent) &&
+		    autofs_type_indirect(sbi->type))
+			__managed_dentry_set_managed(dentry);
+
+		ino = autofs_new_ino(sbi);
+		if (!ino)
+			return ERR_PTR(-ENOMEM);
+
+		dentry->d_fsdata = ino;
+		ino->dentry = dentry;
+
+		autofs_add_active(dentry);
+	}
+	return NULL;
+}
+
+static int autofs_dir_symlink(struct inode *dir,
+			       struct dentry *dentry,
+			       const char *symname)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	struct autofs_info *p_ino;
+	struct inode *inode;
+	size_t size = strlen(symname);
+	char *cp;
+
+	pr_debug("%s <- %pd\n", symname, dentry);
+
+	if (!autofs_oz_mode(sbi))
+		return -EACCES;
+
+	BUG_ON(!ino);
+
+	autofs_clean_ino(ino);
+
+	autofs_del_active(dentry);
+
+	cp = kmalloc(size + 1, GFP_KERNEL);
+	if (!cp)
+		return -ENOMEM;
+
+	strcpy(cp, symname);
+
+	inode = autofs_get_inode(dir->i_sb, S_IFLNK | 0555);
+	if (!inode) {
+		kfree(cp);
+		return -ENOMEM;
+	}
+	inode->i_private = cp;
+	inode->i_size = size;
+	d_add(dentry, inode);
+
+	dget(dentry);
+	atomic_inc(&ino->count);
+	p_ino = autofs_dentry_ino(dentry->d_parent);
+	if (p_ino && !IS_ROOT(dentry))
+		atomic_inc(&p_ino->count);
+
+	dir->i_mtime = current_time(dir);
+
+	return 0;
+}
+
+/*
+ * NOTE!
+ *
+ * Normal filesystems would do a "d_delete()" to tell the VFS dcache
+ * that the file no longer exists. However, doing that means that the
+ * VFS layer can turn the dentry into a negative dentry.  We don't want
+ * this, because the unlink is probably the result of an expire.
+ * We simply d_drop it and add it to a expiring list in the super block,
+ * which allows the dentry lookup to check for an incomplete expire.
+ *
+ * If a process is blocked on the dentry waiting for the expire to finish,
+ * it will invalidate the dentry and try to mount with a new one.
+ *
+ * Also see autofs_dir_rmdir()..
+ */
+static int autofs_dir_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	struct autofs_info *p_ino;
+
+	/* This allows root to remove symlinks */
+	if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (atomic_dec_and_test(&ino->count)) {
+		p_ino = autofs_dentry_ino(dentry->d_parent);
+		if (p_ino && !IS_ROOT(dentry))
+			atomic_dec(&p_ino->count);
+	}
+	dput(ino->dentry);
+
+	d_inode(dentry)->i_size = 0;
+	clear_nlink(d_inode(dentry));
+
+	dir->i_mtime = current_time(dir);
+
+	spin_lock(&sbi->lookup_lock);
+	__autofs_add_expiring(dentry);
+	d_drop(dentry);
+	spin_unlock(&sbi->lookup_lock);
+
+	return 0;
+}
+
+/*
+ * Version 4 of autofs provides a pseudo direct mount implementation
+ * that relies on directories at the leaves of a directory tree under
+ * an indirect mount to trigger mounts. To allow for this we need to
+ * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves
+ * of the directory tree. There is no need to clear the automount flag
+ * following a mount or restore it after an expire because these mounts
+ * are always covered. However, it is necessary to ensure that these
+ * flags are clear on non-empty directories to avoid unnecessary calls
+ * during path walks.
+ */
+static void autofs_set_leaf_automount_flags(struct dentry *dentry)
+{
+	struct dentry *parent;
+
+	/* root and dentrys in the root are already handled */
+	if (IS_ROOT(dentry->d_parent))
+		return;
+
+	managed_dentry_set_managed(dentry);
+
+	parent = dentry->d_parent;
+	/* only consider parents below dentrys in the root */
+	if (IS_ROOT(parent->d_parent))
+		return;
+	managed_dentry_clear_managed(parent);
+}
+
+static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
+{
+	struct list_head *d_child;
+	struct dentry *parent;
+
+	/* flags for dentrys in the root are handled elsewhere */
+	if (IS_ROOT(dentry->d_parent))
+		return;
+
+	managed_dentry_clear_managed(dentry);
+
+	parent = dentry->d_parent;
+	/* only consider parents below dentrys in the root */
+	if (IS_ROOT(parent->d_parent))
+		return;
+	d_child = &dentry->d_child;
+	/* Set parent managed if it's becoming empty */
+	if (d_child->next == &parent->d_subdirs &&
+	    d_child->prev == &parent->d_subdirs)
+		managed_dentry_set_managed(parent);
+}
+
+static int autofs_dir_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	struct autofs_info *p_ino;
+
+	pr_debug("dentry %p, removing %pd\n", dentry, dentry);
+
+	if (!autofs_oz_mode(sbi))
+		return -EACCES;
+
+	spin_lock(&sbi->lookup_lock);
+	if (!simple_empty(dentry)) {
+		spin_unlock(&sbi->lookup_lock);
+		return -ENOTEMPTY;
+	}
+	__autofs_add_expiring(dentry);
+	d_drop(dentry);
+	spin_unlock(&sbi->lookup_lock);
+
+	if (sbi->version < 5)
+		autofs_clear_leaf_automount_flags(dentry);
+
+	if (atomic_dec_and_test(&ino->count)) {
+		p_ino = autofs_dentry_ino(dentry->d_parent);
+		if (p_ino && dentry->d_parent != dentry)
+			atomic_dec(&p_ino->count);
+	}
+	dput(ino->dentry);
+	d_inode(dentry)->i_size = 0;
+	clear_nlink(d_inode(dentry));
+
+	if (dir->i_nlink)
+		drop_nlink(dir);
+
+	return 0;
+}
+
+static int autofs_dir_mkdir(struct inode *dir,
+			    struct dentry *dentry, umode_t mode)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs_dentry_ino(dentry);
+	struct autofs_info *p_ino;
+	struct inode *inode;
+
+	if (!autofs_oz_mode(sbi))
+		return -EACCES;
+
+	pr_debug("dentry %p, creating %pd\n", dentry, dentry);
+
+	BUG_ON(!ino);
+
+	autofs_clean_ino(ino);
+
+	autofs_del_active(dentry);
+
+	inode = autofs_get_inode(dir->i_sb, S_IFDIR | mode);
+	if (!inode)
+		return -ENOMEM;
+	d_add(dentry, inode);
+
+	if (sbi->version < 5)
+		autofs_set_leaf_automount_flags(dentry);
+
+	dget(dentry);
+	atomic_inc(&ino->count);
+	p_ino = autofs_dentry_ino(dentry->d_parent);
+	if (p_ino && !IS_ROOT(dentry))
+		atomic_inc(&p_ino->count);
+	inc_nlink(dir);
+	dir->i_mtime = current_time(dir);
+
+	return 0;
+}
+
+/* Get/set timeout ioctl() operation */
+#ifdef CONFIG_COMPAT
+static inline int autofs_compat_get_set_timeout(struct autofs_sb_info *sbi,
+						 compat_ulong_t __user *p)
+{
+	unsigned long ntimeout;
+	int rv;
+
+	rv = get_user(ntimeout, p);
+	if (rv)
+		goto error;
+
+	rv = put_user(sbi->exp_timeout/HZ, p);
+	if (rv)
+		goto error;
+
+	if (ntimeout > UINT_MAX/HZ)
+		sbi->exp_timeout = 0;
+	else
+		sbi->exp_timeout = ntimeout * HZ;
+
+	return 0;
+error:
+	return rv;
+}
+#endif
+
+static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
+					  unsigned long __user *p)
+{
+	unsigned long ntimeout;
+	int rv;
+
+	rv = get_user(ntimeout, p);
+	if (rv)
+		goto error;
+
+	rv = put_user(sbi->exp_timeout/HZ, p);
+	if (rv)
+		goto error;
+
+	if (ntimeout > ULONG_MAX/HZ)
+		sbi->exp_timeout = 0;
+	else
+		sbi->exp_timeout = ntimeout * HZ;
+
+	return 0;
+error:
+	return rv;
+}
+
+/* Return protocol version */
+static inline int autofs_get_protover(struct autofs_sb_info *sbi,
+				       int __user *p)
+{
+	return put_user(sbi->version, p);
+}
+
+/* Return protocol sub version */
+static inline int autofs_get_protosubver(struct autofs_sb_info *sbi,
+					  int __user *p)
+{
+	return put_user(sbi->sub_version, p);
+}
+
+/*
+* Tells the daemon whether it can umount the autofs mount.
+*/
+static inline int autofs_ask_umount(struct vfsmount *mnt, int __user *p)
+{
+	int status = 0;
+
+	if (may_umount(mnt))
+		status = 1;
+
+	pr_debug("may umount %d\n", status);
+
+	status = put_user(status, p);
+
+	return status;
+}
+
+/* Identify autofs_dentries - this is so we can tell if there's
+ * an extra dentry refcount or not.  We only hold a refcount on the
+ * dentry if its non-negative (ie, d_inode != NULL)
+ */
+int is_autofs_dentry(struct dentry *dentry)
+{
+	return dentry && d_really_is_positive(dentry) &&
+		dentry->d_op == &autofs_dentry_operations &&
+		dentry->d_fsdata != NULL;
+}
+
+/*
+ * ioctl()'s on the root directory is the chief method for the daemon to
+ * generate kernel reactions
+ */
+static int autofs_root_ioctl_unlocked(struct inode *inode, struct file *filp,
+				       unsigned int cmd, unsigned long arg)
+{
+	struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
+	void __user *p = (void __user *)arg;
+
+	pr_debug("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
+		 cmd, arg, sbi, task_pgrp_nr(current));
+
+	if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
+	     _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
+		return -ENOTTY;
+
+	if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	switch (cmd) {
+	case AUTOFS_IOC_READY:	/* Wait queue: go ahead and retry */
+		return autofs_wait_release(sbi, (autofs_wqt_t) arg, 0);
+	case AUTOFS_IOC_FAIL:	/* Wait queue: fail with ENOENT */
+		return autofs_wait_release(sbi, (autofs_wqt_t) arg, -ENOENT);
+	case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
+		autofs_catatonic_mode(sbi);
+		return 0;
+	case AUTOFS_IOC_PROTOVER: /* Get protocol version */
+		return autofs_get_protover(sbi, p);
+	case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
+		return autofs_get_protosubver(sbi, p);
+	case AUTOFS_IOC_SETTIMEOUT:
+		return autofs_get_set_timeout(sbi, p);
+#ifdef CONFIG_COMPAT
+	case AUTOFS_IOC_SETTIMEOUT32:
+		return autofs_compat_get_set_timeout(sbi, p);
+#endif
+
+	case AUTOFS_IOC_ASKUMOUNT:
+		return autofs_ask_umount(filp->f_path.mnt, p);
+
+	/* return a single thing to expire */
+	case AUTOFS_IOC_EXPIRE:
+		return autofs_expire_run(inode->i_sb, filp->f_path.mnt, sbi, p);
+	/* same as above, but can send multiple expires through pipe */
+	case AUTOFS_IOC_EXPIRE_MULTI:
+		return autofs_expire_multi(inode->i_sb,
+					   filp->f_path.mnt, sbi, p);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static long autofs_root_ioctl(struct file *filp,
+			       unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+
+	return autofs_root_ioctl_unlocked(inode, filp, cmd, arg);
+}
+
+#ifdef CONFIG_COMPAT
+static long autofs_root_compat_ioctl(struct file *filp,
+				      unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file_inode(filp);
+	int ret;
+
+	if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
+		ret = autofs_root_ioctl_unlocked(inode, filp, cmd, arg);
+	else
+		ret = autofs_root_ioctl_unlocked(inode, filp, cmd,
+					      (unsigned long) compat_ptr(arg));
+
+	return ret;
+}
+#endif

fs/autofs/symlink.c

+/*
+ * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *
+ * 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 "autofs_i.h"
+
+static const char *autofs_get_link(struct dentry *dentry,
+				   struct inode *inode,
+				   struct delayed_call *done)
+{
+	struct autofs_sb_info *sbi;
+	struct autofs_info *ino;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+	sbi = autofs_sbi(dentry->d_sb);
+	ino = autofs_dentry_ino(dentry);
+	if (ino && !autofs_oz_mode(sbi))
+		ino->last_used = jiffies;
+	return d_inode(dentry)->i_private;
+}
+
+const struct inode_operations autofs_symlink_inode_operations = {
+	.get_link	= autofs_get_link
+};

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/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;
+}