Merge ../linux-2.6

5 files changed, 570 insertions, 318 deletions

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index f54c5b21f87..57c4903614e 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -3,6 +3,7 @@
  * linux/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
@@ -41,14 +42,6 @@
 
 #define AUTOFS_SUPER_MAGIC 0x0187
 
-/*
- * If the daemon returns a negative response (AUTOFS_IOC_FAIL) then the
- * kernel will keep the negative response cached for up to the time given
- * here, although the time can be shorter if the kernel throws the dcache
- * entry away.  This probably should be settable from user space.
- */
-#define AUTOFS_NEGATIVE_TIMEOUT (60*HZ)	/* 1 minute */
-
 /* 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
@@ -63,6 +56,7 @@ struct autofs_info {
 
 	struct autofs_sb_info *sbi;
 	unsigned long last_used;
+	atomic_t count;
 
 	mode_t	mode;
 	size_t	size;
@@ -83,23 +77,37 @@ struct autofs_wait_queue {
 	int hash;
 	int len;
 	char *name;
+	u32 dev;
+	u64 ino;
+	uid_t uid;
+	gid_t gid;
+	pid_t pid;
+	pid_t tgid;
 	/* This is for status reporting upon return */
 	int status;
-	atomic_t notified;
+	atomic_t notify;
 	atomic_t wait_ctr;
 };
 
 #define AUTOFS_SBI_MAGIC 0x6d4a556d
 
+#define AUTOFS_TYPE_INDIRECT     0x0001
+#define AUTOFS_TYPE_DIRECT       0x0002
+#define AUTOFS_TYPE_OFFSET       0x0004
+
 struct autofs_sb_info {
 	u32 magic;
 	struct dentry *root;
+	int pipefd;
 	struct file *pipe;
 	pid_t oz_pgrp;
 	int catatonic;
 	int version;
 	int sub_version;
+	int min_proto;
+	int max_proto;
 	unsigned long exp_timeout;
+	unsigned int type;
 	int reghost_enabled;
 	int needs_reghost;
 	struct super_block *sb;
@@ -166,8 +174,10 @@ int autofs4_expire_multi(struct super_block *, struct vfsmount *,
 extern struct inode_operations autofs4_symlink_inode_operations;
 extern struct inode_operations autofs4_dir_inode_operations;
 extern struct inode_operations autofs4_root_inode_operations;
-extern struct file_operations autofs4_dir_operations;
-extern struct file_operations autofs4_root_operations;
+extern struct inode_operations autofs4_indirect_root_inode_operations;
+extern struct inode_operations autofs4_direct_root_inode_operations;
+extern const struct file_operations autofs4_dir_operations;
+extern const struct file_operations autofs4_root_operations;
 
 /* Initializing function */
 
@@ -176,13 +186,6 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info
 
 /* Queue management functions */
 
-enum autofs_notify
-{
-	NFY_NONE,
-	NFY_MOUNT,
-	NFY_EXPIRE
-};
-
 int autofs4_wait(struct autofs_sb_info *,struct dentry *, enum autofs_notify);
 int autofs4_wait_release(struct autofs_sb_info *,autofs_wqt_t,int);
 void autofs4_catatonic_mode(struct autofs_sb_info *);
@@ -200,12 +203,22 @@ static inline int autofs4_follow_mount(struct vfsmount **mnt, struct dentry **de
 	return res;
 }
 
+static inline u32 autofs4_get_dev(struct autofs_sb_info *sbi)
+{
+	return new_encode_dev(sbi->sb->s_dev);
+}
+
+static inline u64 autofs4_get_ino(struct autofs_sb_info *sbi)
+{
+	return sbi->sb->s_root->d_inode->i_ino;
+}
+
 static inline int simple_positive(struct dentry *dentry)
 {
 	return dentry->d_inode && !d_unhashed(dentry);
 }
 
-static inline int simple_empty_nolock(struct dentry *dentry)
+static inline int __simple_empty(struct dentry *dentry)
 {
 	struct dentry *child;
 	int ret = 0;
@@ -217,3 +230,6 @@ static inline int simple_empty_nolock(struct dentry *dentry)
 out:
 	return ret;
 }
+
+void autofs4_dentry_release(struct dentry *);
+
diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index dc39589df16..b8ce02607d6 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -4,7 +4,7 @@
  *
  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
  *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
- *  Copyright 2001-2003 Ian Kent <raven@themaw.net>
+ *  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
@@ -16,7 +16,7 @@
 
 static unsigned long now;
 
-/* Check if a dentry can be expired return 1 if it can else return 0 */
+/* Check if a dentry can be expired */
 static inline int autofs4_can_expire(struct dentry *dentry,
 					unsigned long timeout, int do_now)
 {
@@ -41,14 +41,14 @@ static inline int autofs4_can_expire(struct dentry *dentry,
 		     attempts if expire fails the first time */
 		ino->last_used = now;
 	}
-
 	return 1;
 }
 
-/* Check a mount point for busyness return 1 if not busy, otherwise */
-static int autofs4_check_mount(struct vfsmount *mnt, struct dentry *dentry)
+/* Check a mount point for busyness */
+static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
 {
-	int status = 0;
+	struct dentry *top = dentry;
+	int status = 1;
 
 	DPRINTK("dentry %p %.*s",
 		dentry, (int)dentry->d_name.len, dentry->d_name.name);
@@ -63,9 +63,14 @@ static int autofs4_check_mount(struct vfsmount *mnt, struct dentry *dentry)
 	if (is_autofs4_dentry(dentry))
 		goto done;
 
-	/* The big question */
-	if (may_umount_tree(mnt) == 0)
-		status = 1;
+	/* Update the expiry counter if fs is busy */
+	if (!may_umount_tree(mnt)) {
+		struct autofs_info *ino = autofs4_dentry_ino(top);
+		ino->last_used = jiffies;
+		goto done;
+	}
+
+	status = 0;
 done:
 	DPRINTK("returning = %d", status);
 	mntput(mnt);
@@ -73,78 +78,124 @@ done:
 	return status;
 }
 
+/*
+ * Calculate next entry in top down tree traversal.
+ * From next_mnt in namespace.c - elegant.
+ */
+static struct dentry *next_dentry(struct dentry *p, struct dentry *root)
+{
+	struct list_head *next = p->d_subdirs.next;
+
+	if (next == &p->d_subdirs) {
+		while (1) {
+			if (p == root)
+				return NULL;
+			next = p->d_u.d_child.next;
+			if (next != &p->d_parent->d_subdirs)
+				break;
+			p = p->d_parent;
+		}
+	}
+	return list_entry(next, struct dentry, d_u.d_child);
+}
+
+/*
+ * 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 autofs4_direct_busy(struct vfsmount *mnt,
+				struct dentry *top,
+				unsigned long timeout,
+				int do_now)
+{
+	DPRINTK("top %p %.*s",
+		top, (int) top->d_name.len, top->d_name.name);
+
+	/* If it's busy update the expiry counters */
+	if (!may_umount_tree(mnt)) {
+		struct autofs_info *ino = autofs4_dentry_ino(top);
+		if (ino)
+			ino->last_used = jiffies;
+		return 1;
+	}
+
+	/* Timeout of a direct mount is determined by its top dentry */
+	if (!autofs4_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
- * Return 1 if the tree is busy or 0 otherwise
  */
-static int autofs4_check_tree(struct vfsmount *mnt,
-	       		      struct dentry *top,
-			      unsigned long timeout,
-			      int do_now)
+static int autofs4_tree_busy(struct vfsmount *mnt,
+	       		     struct dentry *top,
+			     unsigned long timeout,
+			     int do_now)
 {
-	struct dentry *this_parent = top;
-	struct list_head *next;
+	struct autofs_info *top_ino = autofs4_dentry_ino(top);
+	struct dentry *p;
 
-	DPRINTK("parent %p %.*s",
+	DPRINTK("top %p %.*s",
 		top, (int)top->d_name.len, top->d_name.name);
 
 	/* Negative dentry - give up */
 	if (!simple_positive(top))
-		return 0;
-
-	/* Timeout of a tree mount is determined by its top dentry */
-	if (!autofs4_can_expire(top, timeout, do_now))
-		return 0;
-
-	/* Is someone visiting anywhere in the tree ? */
-	if (may_umount_tree(mnt))
-		return 0;
+		return 1;
 
 	spin_lock(&dcache_lock);
-repeat:
-	next = this_parent->d_subdirs.next;
-resume:
-	while (next != &this_parent->d_subdirs) {
-		struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
-
+	for (p = top; p; p = next_dentry(p, top)) {
 		/* Negative dentry - give up */
-		if (!simple_positive(dentry)) {
-			next = next->next;
+		if (!simple_positive(p))
 			continue;
-		}
 
 		DPRINTK("dentry %p %.*s",
-			dentry, (int)dentry->d_name.len, dentry->d_name.name);
-
-		if (!simple_empty_nolock(dentry)) {
-			this_parent = dentry;
-			goto repeat;
-		}
+			p, (int) p->d_name.len, p->d_name.name);
 
-		dentry = dget(dentry);
+		p = dget(p);
 		spin_unlock(&dcache_lock);
 
-		if (d_mountpoint(dentry)) {
-			/* First busy => tree busy */
-			if (!autofs4_check_mount(mnt, dentry)) {
-				dput(dentry);
-				return 0;
+		/*
+		 * 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 (autofs4_mount_busy(mnt, p)) {
+				top_ino->last_used = jiffies;
+				dput(p);
+				return 1;
+			}
+		} else {
+			struct autofs_info *ino = autofs4_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 (atomic_read(&p->d_count) > ino_count) {
+				top_ino->last_used = jiffies;
+				dput(p);
+				return 1;
 			}
 		}
-
-		dput(dentry);
+		dput(p);
 		spin_lock(&dcache_lock);
-		next = next->next;
-	}
-
-	if (this_parent != top) {
-		next = this_parent->d_u.d_child.next;
-		this_parent = this_parent->d_parent;
-		goto resume;
 	}
 	spin_unlock(&dcache_lock);
 
-	return 1;
+	/* Timeout of a tree mount is ultimately determined by its top dentry */
+	if (!autofs4_can_expire(top, timeout, do_now))
+		return 1;
+
+	return 0;
 }
 
 static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
@@ -152,58 +203,68 @@ static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
 					   unsigned long timeout,
 					   int do_now)
 {
-	struct dentry *this_parent = parent;
-	struct list_head *next;
+	struct dentry *p;
 
 	DPRINTK("parent %p %.*s",
 		parent, (int)parent->d_name.len, parent->d_name.name);
 
 	spin_lock(&dcache_lock);
-repeat:
-	next = this_parent->d_subdirs.next;
-resume:
-	while (next != &this_parent->d_subdirs) {
-		struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
-
+	for (p = parent; p; p = next_dentry(p, parent)) {
 		/* Negative dentry - give up */
-		if (!simple_positive(dentry)) {
-			next = next->next;
+		if (!simple_positive(p))
 			continue;
-		}
 
 		DPRINTK("dentry %p %.*s",
-			dentry, (int)dentry->d_name.len, dentry->d_name.name);
-
-		if (!list_empty(&dentry->d_subdirs)) {
-			this_parent = dentry;
-			goto repeat;
-		}
+			p, (int) p->d_name.len, p->d_name.name);
 
-		dentry = dget(dentry);
+		p = dget(p);
 		spin_unlock(&dcache_lock);
 
-		if (d_mountpoint(dentry)) {
-			/* Can we expire this guy */
-			if (!autofs4_can_expire(dentry, timeout, do_now))
-				goto cont;
-
+		if (d_mountpoint(p)) {
 			/* Can we umount this guy */
-			if (autofs4_check_mount(mnt, dentry))
-				return dentry;
+			if (autofs4_mount_busy(mnt, p))
+				goto cont;
 
+			/* Can we expire this guy */
+			if (autofs4_can_expire(p, timeout, do_now))
+				return p;
 		}
 cont:
-		dput(dentry);
+		dput(p);
 		spin_lock(&dcache_lock);
-		next = next->next;
 	}
+	spin_unlock(&dcache_lock);
+	return NULL;
+}
+
+/* Check if we can expire a direct mount (possibly a tree) */
+static struct dentry *autofs4_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;
+
+	if (!sbi->exp_timeout || !root)
+		return NULL;
+
+	now = jiffies;
+	timeout = sbi->exp_timeout;
+
+	/* Lock the tree as we must expire as a whole */
+	spin_lock(&sbi->fs_lock);
+	if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
+		struct autofs_info *ino = autofs4_dentry_ino(root);
 
-	if (this_parent != parent) {
-		next = this_parent->d_u.d_child.next;
-		this_parent = this_parent->d_parent;
-		goto resume;
+		/* Set this flag early to catch sys_chdir and the like */
+		ino->flags |= AUTOFS_INF_EXPIRING;
+		spin_unlock(&sbi->fs_lock);
+		return root;
 	}
-	spin_unlock(&dcache_lock);
+	spin_unlock(&sbi->fs_lock);
+	dput(root);
 
 	return NULL;
 }
@@ -214,10 +275,10 @@ cont:
  *  - it is unused by any user process
  *  - it has been unused for exp_timeout time
  */
-static struct dentry *autofs4_expire(struct super_block *sb,
-				     struct vfsmount *mnt,
-				     struct autofs_sb_info *sbi,
-				     int how)
+static struct dentry *autofs4_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;
@@ -241,7 +302,7 @@ static struct dentry *autofs4_expire(struct super_block *sb,
 		struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
 
 		/* Negative dentry - give up */
-		if ( !simple_positive(dentry) ) {
+		if (!simple_positive(dentry)) {
 			next = next->next;
 			continue;
 		}
@@ -249,31 +310,36 @@ static struct dentry *autofs4_expire(struct super_block *sb,
 		dentry = dget(dentry);
 		spin_unlock(&dcache_lock);
 
-		/* Case 1: indirect mount or top level direct mount */
+		/*
+		 * 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)) {
 			DPRINTK("checking mountpoint %p %.*s",
 				dentry, (int)dentry->d_name.len, dentry->d_name.name);
 
-			/* Can we expire this guy */
-			if (!autofs4_can_expire(dentry, timeout, do_now))
+			/* Can we umount this guy */
+			if (autofs4_mount_busy(mnt, dentry))
 				goto next;
 
-			/* Can we umount this guy */
-			if (autofs4_check_mount(mnt, dentry)) {
+			/* Can we expire this guy */
+			if (autofs4_can_expire(dentry, timeout, do_now)) {
 				expired = dentry;
 				break;
 			}
 			goto next;
 		}
 
-		if ( simple_empty(dentry) )
+		if (simple_empty(dentry))
 			goto next;
 
 		/* Case 2: tree mount, expire iff entire tree is not busy */
 		if (!exp_leaves) {
 			/* Lock the tree as we must expire as a whole */
 			spin_lock(&sbi->fs_lock);
-			if (autofs4_check_tree(mnt, dentry, timeout, do_now)) {
+			if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
 				struct autofs_info *inf = autofs4_dentry_ino(dentry);
 
 				/* Set this flag early to catch sys_chdir and the like */
@@ -283,7 +349,10 @@ static struct dentry *autofs4_expire(struct super_block *sb,
 				break;
 			}
 			spin_unlock(&sbi->fs_lock);
-		/* Case 3: direct mount, expire individual leaves */
+		/*
+		 * Case 3: pseudo direct mount, expire individual leaves
+		 *	   (autofs-4.1).
+		 */
 		} else {
 			expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
 			if (expired) {
@@ -297,7 +366,7 @@ next:
 		next = next->next;
 	}
 
-	if ( expired ) {
+	if (expired) {
 		DPRINTK("returning %p %.*s",
 			expired, (int)expired->d_name.len, expired->d_name.name);
 		spin_lock(&dcache_lock);
@@ -325,7 +394,7 @@ int autofs4_expire_run(struct super_block *sb,
 	pkt.hdr.proto_version = sbi->version;
 	pkt.hdr.type = autofs_ptype_expire;
 
-	if ((dentry = autofs4_expire(sb, mnt, sbi, 0)) == NULL)
+	if ((dentry = autofs4_expire_indirect(sb, mnt, sbi, 0)) == NULL)
 		return -EAGAIN;
 
 	pkt.len = dentry->d_name.len;
@@ -351,17 +420,22 @@ int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
 	if (arg && get_user(do_now, arg))
 		return -EFAULT;
 
-	if ((dentry = autofs4_expire(sb, mnt, sbi, do_now)) != NULL) {
-		struct autofs_info *de_info = autofs4_dentry_ino(dentry);
+	if (sbi->type & AUTOFS_TYPE_DIRECT)
+		dentry = autofs4_expire_direct(sb, mnt, sbi, do_now);
+	else
+		dentry = autofs4_expire_indirect(sb, mnt, sbi, do_now);
+
+	if (dentry) {
+		struct autofs_info *ino = autofs4_dentry_ino(dentry);
 
 		/* This is synchronous because it makes the daemon a
                    little easier */
-		de_info->flags |= AUTOFS_INF_EXPIRING;
+		ino->flags |= AUTOFS_INF_EXPIRING;
 		ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
-		de_info->flags &= ~AUTOFS_INF_EXPIRING;
+		ino->flags &= ~AUTOFS_INF_EXPIRING;
 		dput(dentry);
 	}
-		
+
 	return ret;
 }
 
diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c
index 1ad98d48e55..fde78b110dd 100644
--- a/fs/autofs4/inode.c
+++ b/fs/autofs4/inode.c
@@ -3,6 +3,7 @@
  * linux/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
@@ -13,6 +14,7 @@
 #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>
@@ -46,6 +48,7 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
 	ino->size = 0;
 
 	ino->last_used = jiffies;
+	atomic_set(&ino->count, 0);
 
 	ino->sbi = sbi;
 
@@ -64,10 +67,19 @@ struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
 
 void autofs4_free_ino(struct autofs_info *ino)
 {
+	struct autofs_info *p_ino;
+
 	if (ino->dentry) {
 		ino->dentry->d_fsdata = NULL;
-		if (ino->dentry->d_inode)
+		if (ino->dentry->d_inode) {
+			struct dentry *parent = ino->dentry->d_parent;
+			if (atomic_dec_and_test(&ino->count)) {
+				p_ino = autofs4_dentry_ino(parent);
+				if (p_ino && parent != ino->dentry)
+					atomic_dec(&p_ino->count);
+			}
 			dput(ino->dentry);
+		}
 		ino->dentry = NULL;
 	}
 	if (ino->free)
@@ -145,20 +157,44 @@ static void autofs4_put_super(struct super_block *sb)
 		autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
 
 	/* Clean up and release dangling references */
-	if (sbi)
-		autofs4_force_release(sbi);
+	autofs4_force_release(sbi);
 
 	kfree(sbi);
 
 	DPRINTK("shutting down");
 }
 
+static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
+
+	if (!sbi)
+		return 0;
+
+	seq_printf(m, ",fd=%d", sbi->pipefd);
+	seq_printf(m, ",pgrp=%d", 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 (sbi->type & AUTOFS_TYPE_OFFSET)
+		seq_printf(m, ",offset");
+	else if (sbi->type & AUTOFS_TYPE_DIRECT)
+		seq_printf(m, ",direct");
+	else
+		seq_printf(m, ",indirect");
+
+	return 0;
+}
+
 static struct super_operations autofs4_sops = {
 	.put_super	= autofs4_put_super,
 	.statfs		= simple_statfs,
+	.show_options	= autofs4_show_options,
 };
 
-enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
+enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
+	Opt_indirect, Opt_direct, Opt_offset};
 
 static match_table_t tokens = {
 	{Opt_fd, "fd=%u"},
@@ -167,11 +203,15 @@ static match_table_t tokens = {
 	{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, uid_t *uid, gid_t *gid,
-			 pid_t *pgrp, int *minproto, int *maxproto)
+			 pid_t *pgrp, unsigned int *type,
+			 int *minproto, int *maxproto)
 {
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
@@ -225,6 +265,15 @@ static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
 				return 1;
 			*maxproto = option;
 			break;
+		case Opt_indirect:
+			*type = AUTOFS_TYPE_INDIRECT;
+			break;
+		case Opt_direct:
+			*type = AUTOFS_TYPE_DIRECT;
+			break;
+		case Opt_offset:
+			*type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
+			break;
 		default:
 			return 1;
 		}
@@ -243,6 +292,10 @@ static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
 	return ino;
 }
 
+static struct dentry_operations autofs4_sb_dentry_operations = {
+	.d_release      = autofs4_dentry_release,
+};
+
 int autofs4_fill_super(struct super_block *s, void *data, int silent)
 {
 	struct inode * root_inode;
@@ -251,7 +304,6 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
 	int pipefd;
 	struct autofs_sb_info *sbi;
 	struct autofs_info *ino;
-	int minproto, maxproto;
 
 	sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
 	if ( !sbi )
@@ -263,12 +315,16 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
 	s->s_fs_info = sbi;
 	sbi->magic = AUTOFS_SBI_MAGIC;
 	sbi->root = NULL;
+	sbi->pipefd = -1;
 	sbi->catatonic = 0;
 	sbi->exp_timeout = 0;
 	sbi->oz_pgrp = process_group(current);
 	sbi->sb = s;
 	sbi->version = 0;
 	sbi->sub_version = 0;
+	sbi->type = 0;
+	sbi->min_proto = 0;
+	sbi->max_proto = 0;
 	mutex_init(&sbi->wq_mutex);
 	spin_lock_init(&sbi->fs_lock);
 	sbi->queues = NULL;
@@ -285,38 +341,46 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
 	if (!ino)
 		goto fail_free;
 	root_inode = autofs4_get_inode(s, ino);
-	kfree(ino);
 	if (!root_inode)
-		goto fail_free;
+		goto fail_ino;
 
-	root_inode->i_op = &autofs4_root_inode_operations;
-	root_inode->i_fop = &autofs4_root_operations;
 	root = d_alloc_root(root_inode);
-	pipe = NULL;
-
 	if (!root)
 		goto fail_iput;
+	pipe = NULL;
+
+	root->d_op = &autofs4_sb_dentry_operations;
+	root->d_fsdata = ino;
 
 	/* Can this call block? */
 	if (parse_options(data, &pipefd,
 			  &root_inode->i_uid, &root_inode->i_gid,
-			  &sbi->oz_pgrp,
-			  &minproto, &maxproto)) {
+			  &sbi->oz_pgrp, &sbi->type,
+			  &sbi->min_proto, &sbi->max_proto)) {
 		printk("autofs: called with bogus options\n");
 		goto fail_dput;
 	}
 
+	root_inode->i_fop = &autofs4_root_operations;
+	root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
+			&autofs4_direct_root_inode_operations :
+			&autofs4_indirect_root_inode_operations;
+
 	/* Couldn't this be tested earlier? */
-	if (maxproto < AUTOFS_MIN_PROTO_VERSION ||
-	    minproto > AUTOFS_MAX_PROTO_VERSION) {
+	if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
+	    sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
 		printk("autofs: kernel does not match daemon version "
 		       "daemon (%d, %d) kernel (%d, %d)\n",
-			minproto, maxproto,
+			sbi->min_proto, sbi->max_proto,
 			AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
 		goto fail_dput;
 	}
 
-	sbi->version = maxproto > AUTOFS_MAX_PROTO_VERSION ? AUTOFS_MAX_PROTO_VERSION : maxproto;
+	/* 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;
 
 	DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
@@ -329,6 +393,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent)
 	if ( !pipe->f_op || !pipe->f_op->write )
 		goto fail_fput;
 	sbi->pipe = pipe;
+	sbi->pipefd = pipefd;
 
 	/*
 	 * Take a reference to the root dentry so we get a chance to
@@ -356,6 +421,8 @@ fail_dput:
 fail_iput:
 	printk("autofs: get root dentry failed\n");
 	iput(root_inode);
+fail_ino:
+	kfree(ino);
 fail_free:
 	kfree(sbi);
 fail_unlock:
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 62d8d4acb8b..84e030c8ddd 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -4,7 +4,7 @@
  *
  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
  *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
- *  Copyright 2001-2003 Ian Kent <raven@themaw.net>
+ *  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
@@ -30,9 +30,9 @@ static int autofs4_dir_close(struct inode *inode, struct file *file);
 static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
 static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
-static int autofs4_dcache_readdir(struct file *, void *, filldir_t);
+static void *autofs4_follow_link(struct dentry *, struct nameidata *);
 
-struct file_operations autofs4_root_operations = {
+const struct file_operations autofs4_root_operations = {
 	.open		= dcache_dir_open,
 	.release	= dcache_dir_close,
 	.read		= generic_read_dir,
@@ -40,14 +40,14 @@ struct file_operations autofs4_root_operations = {
 	.ioctl		= autofs4_root_ioctl,
 };
 
-struct file_operations autofs4_dir_operations = {
+const struct file_operations autofs4_dir_operations = {
 	.open		= autofs4_dir_open,
 	.release	= autofs4_dir_close,
 	.read		= generic_read_dir,
 	.readdir	= autofs4_dir_readdir,
 };
 
-struct inode_operations autofs4_root_inode_operations = {
+struct inode_operations autofs4_indirect_root_inode_operations = {
 	.lookup		= autofs4_lookup,
 	.unlink		= autofs4_dir_unlink,
 	.symlink	= autofs4_dir_symlink,
@@ -55,6 +55,14 @@ struct inode_operations autofs4_root_inode_operations = {
 	.rmdir		= autofs4_dir_rmdir,
 };
 
+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,
+};
+
 struct inode_operations autofs4_dir_inode_operations = {
 	.lookup		= autofs4_lookup,
 	.unlink		= autofs4_dir_unlink,
@@ -82,87 +90,7 @@ static int autofs4_root_readdir(struct file *file, void *dirent,
 
 	DPRINTK("needs_reghost = %d", sbi->needs_reghost);
 
-	return autofs4_dcache_readdir(file, dirent, filldir);
-}
-
-/* Update usage from here to top of tree, so that scan of
-   top-level directories will give a useful result */
-static void autofs4_update_usage(struct vfsmount *mnt, struct dentry *dentry)
-{
-	struct dentry *top = dentry->d_sb->s_root;
-
-	spin_lock(&dcache_lock);
-	for(; dentry != top; dentry = dentry->d_parent) {
-		struct autofs_info *ino = autofs4_dentry_ino(dentry);
-
-		if (ino) {
-			touch_atime(mnt, dentry);
-			ino->last_used = jiffies;
-		}
-	}
-	spin_unlock(&dcache_lock);
-}
-
-/*
- * From 2.4 kernel readdir.c
- */
-static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
-{
-	int i;
-	struct dentry *dentry = filp->f_dentry;
-
-	i = filp->f_pos;
-	switch (i) {
-		case 0:
-			if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0)
-				break;
-			i++;
-			filp->f_pos++;
-			/* fallthrough */
-		case 1:
-			if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0)
-				break;
-			i++;
-			filp->f_pos++;
-			/* fallthrough */
-		default: {
-			struct list_head *list;
-			int j = i-2;
-
-			spin_lock(&dcache_lock);
-			list = dentry->d_subdirs.next;
-
-			for (;;) {
-				if (list == &dentry->d_subdirs) {
-					spin_unlock(&dcache_lock);
-					return 0;
-				}
-				if (!j)
-					break;
-				j--;
-				list = list->next;
-			}
-
-			while(1) {
-				struct dentry *de = list_entry(list,
-						struct dentry, d_u.d_child);
-
-				if (!d_unhashed(de) && de->d_inode) {
-					spin_unlock(&dcache_lock);
-					if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0)
-						break;
-					spin_lock(&dcache_lock);
-				}
-				filp->f_pos++;
-				list = list->next;
-				if (list != &dentry->d_subdirs)
-					continue;
-				spin_unlock(&dcache_lock);
-				break;
-			}
-		}
-	}
-	return 0;
+	return dcache_readdir(file, dirent, filldir);
 }
 
 static int autofs4_dir_open(struct inode *inode, struct file *file)
@@ -170,8 +98,16 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
 	struct dentry *dentry = file->f_dentry;
 	struct vfsmount *mnt = file->f_vfsmnt;
 	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct dentry *cursor;
 	int status;
 
+	status = dcache_dir_open(inode, file);
+	if (status)
+		goto out;
+
+	cursor = file->private_data;
+	cursor->d_fsdata = NULL;
+
 	DPRINTK("file=%p dentry=%p %.*s",
 		file, dentry, dentry->d_name.len, dentry->d_name.name);
 
@@ -180,12 +116,15 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
 
 	if (autofs4_ispending(dentry)) {
 		DPRINTK("dentry busy");
-		return -EBUSY;
+		dcache_dir_close(inode, file);
+		status = -EBUSY;
+		goto out;
 	}
 
+	status = -ENOENT;
 	if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
 		struct nameidata nd;
-		int empty;
+		int empty, ret;
 
 		/* In case there are stale directory dentrys from a failed mount */
 		spin_lock(&dcache_lock);
@@ -195,13 +134,13 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
 		if (!empty)
 			d_invalidate(dentry);
 
-		nd.dentry = dentry;
-		nd.mnt = mnt;
 		nd.flags = LOOKUP_DIRECTORY;
-		status = (dentry->d_op->d_revalidate)(dentry, &nd);
+		ret = (dentry->d_op->d_revalidate)(dentry, &nd);
 
-		if (!status)
-			return -ENOENT;
+		if (!ret) {
+			dcache_dir_close(inode, file);
+			goto out;
+		}
 	}
 
 	if (d_mountpoint(dentry)) {
@@ -212,25 +151,29 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
 		if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
 			dput(fp_dentry);
 			mntput(fp_mnt);
-			return -ENOENT;
+			dcache_dir_close(inode, file);
+			goto out;
 		}
 
 		fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
 		status = PTR_ERR(fp);
 		if (IS_ERR(fp)) {
-			file->private_data = NULL;
-			return status;
+			dcache_dir_close(inode, file);
+			goto out;
 		}
-		file->private_data = fp;
+		cursor->d_fsdata = fp;
 	}
-out:
 	return 0;
+out:
+	return status;
 }
 
 static int autofs4_dir_close(struct inode *inode, struct file *file)
 {
 	struct dentry *dentry = file->f_dentry;
 	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct dentry *cursor = file->private_data;
+	int status = 0;
 
 	DPRINTK("file=%p dentry=%p %.*s",
 		file, dentry, dentry->d_name.len, dentry->d_name.name);
@@ -240,26 +183,28 @@ static int autofs4_dir_close(struct inode *inode, struct file *file)
 
 	if (autofs4_ispending(dentry)) {
 		DPRINTK("dentry busy");
-		return -EBUSY;
+		status = -EBUSY;
+		goto out;
 	}
 
 	if (d_mountpoint(dentry)) {
-		struct file *fp = file->private_data;
-
-		if (!fp)
-			return -ENOENT;
-
+		struct file *fp = cursor->d_fsdata;
+		if (!fp) {
+			status = -ENOENT;
+			goto out;
+		}
 		filp_close(fp, current->files);
-		file->private_data = NULL;
 	}
 out:
-	return 0;
+	dcache_dir_close(inode, file);
+	return status;
 }
 
 static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
 {
 	struct dentry *dentry = file->f_dentry;
 	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+	struct dentry *cursor = file->private_data;
 	int status;
 
 	DPRINTK("file