1 files changed, 315 insertions, 428 deletions

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 651e4ef563b..014e7aba3b0 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -35,10 +35,9 @@ static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long);
 #endif
 static int autofs4_dir_open(struct inode *inode, struct file *file);
 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
-static void *autofs4_follow_link(struct dentry *, struct nameidata *);
-
-#define TRIGGER_FLAGS   (LOOKUP_CONTINUE | LOOKUP_DIRECTORY)
-#define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE)
+static struct vfsmount *autofs4_d_automount(struct path *);
+static int autofs4_d_manage(struct dentry *, bool, bool);
+static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
 	.open		= dcache_dir_open,
@@ -60,7 +59,7 @@ const struct file_operations autofs4_dir_operations = {
 	.llseek		= dcache_dir_lseek,
 };
 
-const struct inode_operations autofs4_indirect_root_inode_operations = {
+const struct inode_operations autofs4_dir_inode_operations = {
 	.lookup		= autofs4_lookup,
 	.unlink		= autofs4_dir_unlink,
 	.symlink	= autofs4_dir_symlink,
@@ -68,20 +67,10 @@ const struct inode_operations autofs4_indirect_root_inode_operations = {
 	.rmdir		= autofs4_dir_rmdir,
 };
 
-const struct inode_operations autofs4_direct_root_inode_operations = {
-	.lookup		= autofs4_lookup,
-	.unlink		= autofs4_dir_unlink,
-	.mkdir		= autofs4_dir_mkdir,
-	.rmdir		= autofs4_dir_rmdir,
-	.follow_link	= autofs4_follow_link,
-};
-
-const struct inode_operations autofs4_dir_inode_operations = {
-	.lookup		= autofs4_lookup,
-	.unlink		= autofs4_dir_unlink,
-	.symlink	= autofs4_dir_symlink,
-	.mkdir		= autofs4_dir_mkdir,
-	.rmdir		= autofs4_dir_rmdir,
+const struct dentry_operations autofs4_dentry_operations = {
+	.d_automount	= autofs4_d_automount,
+	.d_manage	= autofs4_d_manage,
+	.d_release	= autofs4_dentry_release,
 };
 
 static void autofs4_add_active(struct dentry *dentry)
@@ -116,14 +105,6 @@ static void autofs4_del_active(struct dentry *dentry)
 	return;
 }
 
-static unsigned int autofs4_need_mount(unsigned int flags)
-{
-	unsigned int res = 0;
-	if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS))
-		res = 1;
-	return res;
-}
-
 static int autofs4_dir_open(struct inode *inode, struct file *file)
 {
 	struct dentry *dentry = file->f_path.dentry;
@@ -158,278 +139,27 @@ out:
 	return dcache_dir_open(inode, file);
 }
 
-static int try_to_fill_dentry(struct dentry *dentry, int flags)
-{
-	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
-	struct autofs_info *ino = autofs4_dentry_ino(dentry);
-	int status;
-
-	DPRINTK("dentry=%p %.*s ino=%p",
-		 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
-
-	/*
-	 * Wait for a pending mount, triggering one if there
-	 * isn't one already
-	 */
-	if (dentry->d_inode == NULL) {
-		DPRINTK("waiting for mount name=%.*s",
-			 dentry->d_name.len, dentry->d_name.name);
-
-		status = autofs4_wait(sbi, dentry, NFY_MOUNT);
-
-		DPRINTK("mount done status=%d", status);
-
-		/* Turn this into a real negative dentry? */
-		if (status == -ENOENT) {
-			spin_lock(&sbi->fs_lock);
-			ino->flags &= ~AUTOFS_INF_PENDING;
-			spin_unlock(&sbi->fs_lock);
-			return status;
-		} else if (status) {
-			/* Return a negative dentry, but leave it "pending" */
-			return status;
-		}
-	/* Trigger mount for path component or follow link */
-	} else if (ino->flags & AUTOFS_INF_PENDING ||
-			autofs4_need_mount(flags)) {
-		DPRINTK("waiting for mount name=%.*s",
-			dentry->d_name.len, dentry->d_name.name);
-
-		spin_lock(&sbi->fs_lock);
-		ino->flags |= AUTOFS_INF_PENDING;
-		spin_unlock(&sbi->fs_lock);
-		status = autofs4_wait(sbi, dentry, NFY_MOUNT);
-
-		DPRINTK("mount done status=%d", status);
-
-		if (status) {
-			spin_lock(&sbi->fs_lock);
-			ino->flags &= ~AUTOFS_INF_PENDING;
-			spin_unlock(&sbi->fs_lock);
-			return status;
-		}
-	}
-
-	/* Initialize expiry counter after successful mount */
-	ino->last_used = jiffies;
-
-	spin_lock(&sbi->fs_lock);
-	ino->flags &= ~AUTOFS_INF_PENDING;
-	spin_unlock(&sbi->fs_lock);
-
-	return 0;
-}
-
-/* For autofs direct mounts the follow link triggers the mount */
-static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
-	struct autofs_info *ino = autofs4_dentry_ino(dentry);
-	int oz_mode = autofs4_oz_mode(sbi);
-	unsigned int lookup_type;
-	int status;
-
-	DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
-		dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
-		nd->flags);
-	/*
-	 * For an expire of a covered direct or offset mount we need
-	 * to break out of follow_down() at the autofs mount trigger
-	 * (d_mounted--), so we can see the expiring flag, and manage
-	 * the blocking and following here until the expire is completed.
-	 */
-	if (oz_mode) {
-		spin_lock(&sbi->fs_lock);
-		if (ino->flags & AUTOFS_INF_EXPIRING) {
-			spin_unlock(&sbi->fs_lock);
-			/* Follow down to our covering mount. */
-			if (!follow_down(&nd->path))
-				goto done;
-			goto follow;
-		}
-		spin_unlock(&sbi->fs_lock);
-		goto done;
-	}
-
-	/* If an expire request is pending everyone must wait. */
-	autofs4_expire_wait(dentry);
-
-	/* We trigger a mount for almost all flags */
-	lookup_type = autofs4_need_mount(nd->flags);
-	spin_lock(&sbi->fs_lock);
-	spin_lock(&autofs4_lock);
-	spin_lock(&dentry->d_lock);
-	if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) {
-		spin_unlock(&dentry->d_lock);
-		spin_unlock(&autofs4_lock);
-		spin_unlock(&sbi->fs_lock);
-		goto follow;
-	}
-
-	/*
-	 * If the dentry contains directories then it is an autofs
-	 * multi-mount with no root mount offset. So don't try to
-	 * mount it again.
-	 */
-	if (ino->flags & AUTOFS_INF_PENDING ||
-	    (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) {
-		spin_unlock(&dentry->d_lock);
-		spin_unlock(&autofs4_lock);
-		spin_unlock(&sbi->fs_lock);
-
-		status = try_to_fill_dentry(dentry, nd->flags);
-		if (status)
-			goto out_error;
-
-		goto follow;
-	}
-	spin_unlock(&dentry->d_lock);
-	spin_unlock(&autofs4_lock);
-	spin_unlock(&sbi->fs_lock);
-follow:
-	/*
-	 * If there is no root mount it must be an autofs
-	 * multi-mount with no root offset so we don't need
-	 * to follow it.
-	 */
-	if (d_mountpoint(dentry)) {
-		if (!autofs4_follow_mount(&nd->path)) {
-			status = -ENOENT;
-			goto out_error;
-		}
-	}
-
-done:
-	return NULL;
-
-out_error:
-	path_put(&nd->path);
-	return ERR_PTR(status);
-}
-
-/*
- * Revalidate is called on every cache lookup.  Some of those
- * cache lookups may actually happen while the dentry is not
- * yet completely filled in, and revalidate has to delay such
- * lookups..
- */
-static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
+static void autofs4_dentry_release(struct dentry *de)
 {
-	struct inode *dir;
-	struct autofs_sb_info *sbi;
-	int oz_mode;
-	int flags = nd ? nd->flags : 0;
-	int status = 1;
-
-	if (flags & LOOKUP_RCU)
-		return -ECHILD;
-
-	dir = dentry->d_parent->d_inode;
-	sbi = autofs4_sbi(dir->i_sb);
-	oz_mode = autofs4_oz_mode(sbi);
-
-	/* Pending dentry */
-	spin_lock(&sbi->fs_lock);
-	if (autofs4_ispending(dentry)) {
-		/* The daemon never causes a mount to trigger */
-		spin_unlock(&sbi->fs_lock);
-
-		if (oz_mode)
-			return 1;
-
-		/*
-		 * If the directory has gone away due to an expire
-		 * we have been called as ->d_revalidate() and so
-		 * we need to return false and proceed to ->lookup().
-		 */
-		if (autofs4_expire_wait(dentry) == -EAGAIN)
-			return 0;
-
-		/*
-		 * A zero status is success otherwise we have a
-		 * negative error code.
-		 */
-		status = try_to_fill_dentry(dentry, flags);
-		if (status == 0)
-			return 1;
-
-		return status;
-	}
-	spin_unlock(&sbi->fs_lock);
-
-	/* Negative dentry.. invalidate if "old" */
-	if (dentry->d_inode == NULL)
-		return 0;
-
-	/* Check for a non-mountpoint directory with no contents */
-	spin_lock(&autofs4_lock);
-	spin_lock(&dentry->d_lock);
-	if (S_ISDIR(dentry->d_inode->i_mode) &&
-	    !d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
-		DPRINTK("dentry=%p %.*s, emptydir",
-			 dentry, dentry->d_name.len, dentry->d_name.name);
-		spin_unlock(&dentry->d_lock);
-		spin_unlock(&autofs4_lock);
-
-		/* The daemon never causes a mount to trigger */
-		if (oz_mode)
-			return 1;
-
-		/*
-		 * A zero status is success otherwise we have a
-		 * negative error code.
-		 */
-		status = try_to_fill_dentry(dentry, flags);
-		if (status == 0)
-			return 1;
-
-		return status;
-	}
-	spin_unlock(&dentry->d_lock);
-	spin_unlock(&autofs4_lock);
-
-	return 1;
-}
-
-void autofs4_dentry_release(struct dentry *de)
-{
-	struct autofs_info *inf;
+	struct autofs_info *ino = autofs4_dentry_ino(de);
+	struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
 
 	DPRINTK("releasing %p", de);
 
-	inf = autofs4_dentry_ino(de);
-	de->d_fsdata = NULL;
-
-	if (inf) {
-		struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
-
-		if (sbi) {
-			spin_lock(&sbi->lookup_lock);
-			if (!list_empty(&inf->active))
-				list_del(&inf->active);
-			if (!list_empty(&inf->expiring))
-				list_del(&inf->expiring);
-			spin_unlock(&sbi->lookup_lock);
-		}
-
-		inf->dentry = NULL;
-		inf->inode = NULL;
+	if (!ino)
+		return;
 
-		autofs4_free_ino(inf);
+	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);
 	}
-}
 
-/* For dentries of directories in the root dir */
-static const struct dentry_operations autofs4_root_dentry_operations = {
-	.d_revalidate	= autofs4_revalidate,
-	.d_release	= autofs4_dentry_release,
-};
-
-/* For other dentries */
-static const struct dentry_operations autofs4_dentry_operations = {
-	.d_revalidate	= autofs4_revalidate,
-	.d_release	= autofs4_dentry_release,
-};
+	autofs4_free_ino(ino);
+}
 
 static struct dentry *autofs4_lookup_active(struct dentry *dentry)
 {
@@ -541,51 +271,246 @@ next:
 	return NULL;
 }
 
+static int autofs4_mount_wait(struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	int status;
+
+	if (ino->flags & AUTOFS_INF_PENDING) {
+		DPRINTK("waiting for mount name=%.*s",
+			dentry->d_name.len, dentry->d_name.name);
+		status = autofs4_wait(sbi, dentry, NFY_MOUNT);
+		DPRINTK("mount wait done status=%d", status);
+		ino->last_used = jiffies;
+		return status;
+	}
+	return 0;
+}
+
+static int do_expire_wait(struct dentry *dentry)
+{
+	struct dentry *expiring;
+
+	expiring = autofs4_lookup_expiring(dentry);
+	if (!expiring)
+		return autofs4_expire_wait(dentry);
+	else {
+		/*
+		 * 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.
+		 */
+		autofs4_expire_wait(expiring);
+		autofs4_del_expiring(expiring);
+		dput(expiring);
+	}
+	return 0;
+}
+
+static struct dentry *autofs4_mountpoint_changed(struct path *path)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_sb_info *sbi = autofs4_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 dentry *new = d_lookup(parent, &dentry->d_name);
+		if (!new)
+			return NULL;
+		dput(path->dentry);
+		path->dentry = new;
+	}
+	return path->dentry;
+}
+
+static struct vfsmount *autofs4_d_automount(struct path *path)
+{
+	struct dentry *dentry = path->dentry;
+	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	int status;
+
+	DPRINTK("dentry=%p %.*s",
+		dentry, dentry->d_name.len, dentry->d_name.name);
+
+	/*
+	 * Someone may have manually umounted this or it was a submount
+	 * that has gone away.
+	 */
+	spin_lock(&dentry->d_lock);
+	if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
+		if (!(dentry->d_flags & DCACHE_MANAGE_TRANSIT) &&
+		     (dentry->d_flags & DCACHE_NEED_AUTOMOUNT))
+			__managed_dentry_set_transit(path->dentry);
+	}
+	spin_unlock(&dentry->d_lock);
+
+	/* The daemon never triggers a mount. */
+	if (autofs4_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(dentry);
+	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 = autofs4_mount_wait(dentry);
+		if (status)
+			return ERR_PTR(status);
+		spin_lock(&sbi->fs_lock);
+		goto done;
+	}
+
+	/*
+	 * If the dentry is a symlink it's equivalent to a directory
+	 * having d_mountpoint() true, so there's no need to call back
+	 * to the daemon.
+	 */
+	if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))
+		goto done;
+	if (!d_mountpoint(dentry)) {
+		/*
+		 * It's possible that user space hasn't removed directories
+		 * after umounting a rootless multi-mount, although it
+		 * should. For v5 have_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 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 (have_submounts(dentry))
+				goto done;
+		} else {
+			spin_lock(&dentry->d_lock);
+			if (!list_empty(&dentry->d_subdirs)) {
+				spin_unlock(&dentry->d_lock);
+				goto done;
+			}
+			spin_unlock(&dentry->d_lock);
+		}
+		ino->flags |= AUTOFS_INF_PENDING;
+		spin_unlock(&sbi->fs_lock);
+		status = autofs4_mount_wait(dentry);
+		if (status)
+			return ERR_PTR(status);
+		spin_lock(&sbi->fs_lock);
+		ino->flags &= ~AUTOFS_INF_PENDING;
+	}
+done:
+	if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
+		/*
+		 * Any needed mounting has been completed and the path updated
+		 * so turn this into a normal dentry so we don't continually
+		 * call ->d_automount() and ->d_manage().
+		 */
+		spin_lock(&dentry->d_lock);
+		__managed_dentry_clear_transit(dentry);
+		/*
+		 * Only clear DMANAGED_AUTOMOUNT for rootless multi-mounts and
+		 * symlinks as in all other cases the dentry will be covered by
+		 * an actual mount so ->d_automount() won't be called during
+		 * the follow.
+		 */
+		if ((!d_mountpoint(dentry) &&
+		    !list_empty(&dentry->d_subdirs)) ||
+		    (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)))
+			__managed_dentry_clear_automount(dentry);
+		spin_unlock(&dentry->d_lock);
+	}
+	spin_unlock(&sbi->fs_lock);
+
+	/* Mount succeeded, check if we ended up with a new dentry */
+	dentry = autofs4_mountpoint_changed(path);
+	if (!dentry)
+		return ERR_PTR(-ENOENT);
+
+	return NULL;
+}
+
+int autofs4_d_manage(struct dentry *dentry, bool mounting_here, bool rcu_walk)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+
+	DPRINTK("dentry=%p %.*s",
+		dentry, dentry->d_name.len, dentry->d_name.name);
+
+	/* The daemon never waits. */
+	if (autofs4_oz_mode(sbi) || mounting_here) {
+		if (!d_mountpoint(dentry))
+			return -EISDIR;
+		return 0;
+	}
+
+	/* We need to sleep, so we need pathwalk to be in ref-mode */
+	if (rcu_walk)
+		return -ECHILD;
+
+	/* Wait for pending expires */
+	do_expire_wait(dentry);
+
+	/*
+	 * This dentry may be under construction so wait on mount
+	 * completion.
+	 */
+	return autofs4_mount_wait(dentry);
+}
+
 /* Lookups in the root directory */
 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
 	struct autofs_sb_info *sbi;
 	struct autofs_info *ino;
-	struct dentry *expiring, *active;
-	int oz_mode;
+	struct dentry *active;
 
-	DPRINTK("name = %.*s",
-		dentry->d_name.len, dentry->d_name.name);
+	DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name);
 
 	/* File name too long to exist */
 	if (dentry->d_name.len > NAME_MAX)
 		return ERR_PTR(-ENAMETOOLONG);
 
 	sbi = autofs4_sbi(dir->i_sb);
-	oz_mode = autofs4_oz_mode(sbi);
 
 	DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
-		 current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
+		current->pid, task_pgrp_nr(current), sbi->catatonic,
+		autofs4_oz_mode(sbi));
 
 	active = autofs4_lookup_active(dentry);
 	if (active) {
-		dentry = active;
-		ino = autofs4_dentry_ino(dentry);
+		return active;
 	} else {
 		/*
-		 * Mark the dentry incomplete but don't hash it. We do this
-		 * to serialize our inode creation operations (symlink and
-		 * mkdir) which prevents deadlock during the callback to
-		 * the daemon. Subsequent user space lookups for the same
-		 * dentry are placed on the wait queue while the daemon
-		 * itself is allowed passage unresticted so the create
-		 * operation itself can then hash the dentry. Finally,
-		 * we check for the hashed dentry and return the newly
-		 * hashed dentry.
+		 * 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.
 		 */
-		d_set_d_op(dentry, &autofs4_root_dentry_operations);
+		if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
+			return ERR_PTR(-ENOENT);
 
-		/*
-		 * And we need to ensure that the same dentry is used for
-		 * all following lookup calls until it is hashed so that
-		 * the dentry flags are persistent throughout the request.
-		 */
-		ino = autofs4_init_ino(NULL, sbi, 0555);
+		/* Mark entries in the root as mount triggers */
+		if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent))
+			__managed_dentry_set_managed(dentry);
+
+		ino = autofs4_new_ino(sbi);
 		if (!ino)
 			return ERR_PTR(-ENOMEM);
 
@@ -596,82 +521,6 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
 
 		d_instantiate(dentry, NULL);
 	}
-
-	if (!oz_mode) {
-		mutex_unlock(&dir->i_mutex);
-		expiring = autofs4_lookup_expiring(dentry);
-		if (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, so just wait for it.
-			 */
-			autofs4_expire_wait(expiring);
-			autofs4_del_expiring(expiring);
-			dput(expiring);
-		}
-
-		spin_lock(&sbi->fs_lock);
-		ino->flags |= AUTOFS_INF_PENDING;
-		spin_unlock(&sbi->fs_lock);
-		if (dentry->d_op && dentry->d_op->d_revalidate)
-			(dentry->d_op->d_revalidate)(dentry, nd);
-		mutex_lock(&dir->i_mutex);
-	}
-
-	/*
-	 * If we are still pending, check if we had to handle
-	 * a signal. If so we can force a restart..
-	 */
-	if (ino->flags & AUTOFS_INF_PENDING) {
-		/* See if we were interrupted */
-		if (signal_pending(current)) {
-			sigset_t *sigset = &current->pending.signal;
-			if (sigismember (sigset, SIGKILL) ||
-			    sigismember (sigset, SIGQUIT) ||
-			    sigismember (sigset, SIGINT)) {
-			    if (active)
-				dput(active);
-			    return ERR_PTR(-ERESTARTNOINTR);
-			}
-		}
-		if (!oz_mode) {
-			spin_lock(&sbi->fs_lock);
-			ino->flags &= ~AUTOFS_INF_PENDING;
-			spin_unlock(&sbi->fs_lock);
-		}
-	}
-
-	/*
-	 * If this dentry is unhashed, then we shouldn't honour this
-	 * lookup.  Returning ENOENT here doesn't do the right thing
-	 * for all system calls, but it should be OK for the operations
-	 * we permit from an autofs.
-	 */
-	if (!oz_mode && d_unhashed(dentry)) {
-		/*
-		 * A user space application can (and has done in the past)
-		 * remove and re-create this directory during the callback.
-		 * This can leave us with an unhashed dentry, but a
-		 * successful mount!  So we need to perform another
-		 * cached lookup in case the dentry now exists.
-		 */
-		struct dentry *parent = dentry->d_parent;
-		struct dentry *new = d_lookup(parent, &dentry->d_name);
-		if (new != NULL)
-			dentry = new;
-		else
-			dentry = ERR_PTR(-ENOENT);
-
-		if (active)
-			dput(active);
-
-		return dentry;
-	}
-
-	if (active)
-		return active;
-
 	return NULL;
 }
 
@@ -683,6 +532,7 @@ static int autofs4_dir_symlink(struct inode *dir,
 	struct autofs_info *ino = autofs4_dentry_ino(dentry);
 	struct autofs_info *p_ino;
 	struct inode *inode;
+	size_t size = strlen(symname);
 	char *cp;
 
 	DPRINTK("%s <- %.*s", symname,
@@ -691,45 +541,35 @@ static int autofs4_dir_symlink(struct inode *dir,
 	if (!autofs4_oz_mode(sbi))
 		return -EACCES;
 
-	ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
-	if (!ino)
-		return -ENOMEM;
+	BUG_ON(!ino);
+
+	autofs4_clean_ino(ino);
 
 	autofs4_del_active(dentry);
 
-	ino->size = strlen(symname);
-	cp = kmalloc(ino->size + 1, GFP_KERNEL);
-	if (!cp) {
-		if (!dentry->d_fsdata)
-			kfree(ino);
+	cp = kmalloc(size + 1, GFP_KERNEL);
+	if (!cp)
 		return -ENOMEM;
-	}
 
 	strcpy(cp, symname);
 
-	inode = autofs4_get_inode(dir->i_sb, ino);
+	inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555);
 	if (!inode) {
 		kfree(cp);
 		if (!dentry->d_fsdata)
 			kfree(ino);
 		return -ENOMEM;
 	}
+	inode->i_private = cp;
+	inode->i_size = size;
 	d_add(dentry, inode);
 
-	if (dir == dir->i_sb->s_root->d_inode)
-		d_set_d_op(dentry, &autofs4_root_dentry_operations);
-	else
-		d_set_d_op(dentry, &autofs4_dentry_operations);
-
-	dentry->d_fsdata = ino;
-	ino->dentry = dget(dentry);
+	dget(dentry);
 	atomic_inc(&ino->count);
 	p_ino = autofs4_dentry_ino(dentry->d_parent);
 	if (p_ino && dentry->d_parent != dentry)
 		atomic_inc(&p_ino->count);
-	ino->inode = inode;
 
-	ino->u.symlink = cp;
 	dir->i_mtime = CURRENT_TIME;
 
 	return 0;
@@ -782,6 +622,58 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 	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 neccessary 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);
+	return;
+}
+
+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_u.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);
+	return;
+}
+
 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 {
 	struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
@@ -809,6 +701,9 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 	spin_unlock(&dentry->d_lock);
 	spin_unlock(&autofs4_lock);
 
+	if (sbi->version < 5)
+		autofs_clear_leaf_automount_flags(dentry);
+
 	if (atomic_dec_and_test(&ino->count)) {
 		p_ino = autofs4_dentry_ino(dentry->d_parent);
 		if (p_ino && dentry->d_parent != dentry)
@@ -837,32 +732,25 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 	DPRINTK("dentry %p, creating %.*s",
 		dentry, dentry->d_name.len, dentry->d_name.name);
 
-	ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
-	if (!ino)
-		return -ENOMEM;
+	BUG_ON(!ino);
+
+	autofs4_clean_ino(ino);
 
 	autofs4_del_active(dentry);
 
-	inode = autofs4_get_inode(dir->i_sb, ino);
-	if (!inode) {
-		if (!dentry->d_fsdata)
-			kfree(ino);
+	inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555);
+	if (!inode)
 		return -ENOMEM;
-	}
 	d_add(dentry, inode);
 
-	if (dir == dir->i_sb->s_root->d_inode)
-		d_set_d_op(dentry, &autofs4_root_dentry_operations);
-	else
-		d_set_d_op(dentry, &autofs4_dentry_operations);
+	if (sbi->version < 5)
+		autofs_set_leaf_automount_flags(dentry);
 
-	dentry->d_fsdata = ino;
-	ino->dentry = dget(dentry);
+	dget(dentry);
 	atomic_inc(&ino->count);
 	p_ino = autofs4_dentry_ino(dentry->d_parent);
 	if (p_ino && dentry->d_parent != dentry)
 		atomic_inc(&p_ino->count);
-	ino->inode = inode;
 	inc_nlink(dir);
 	dir->i_mtime = CURRENT_TIME;
 
@@ -944,8 +832,7 @@ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 int is_autofs4_dentry(struct dentry *dentry)
 {
 	return dentry && dentry->d_inode &&
-		(dentry->d_op == &autofs4_root_dentry_operations ||
-		 dentry->d_op == &autofs4_dentry_operations) &&
+		dentry->d_op == &autofs4_dentry_operations &&
 		dentry->d_fsdata != NULL;
 }