Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

fs/autofs4/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the linux autofs-filesystem routines.
+#
+
+obj-$(CONFIG_AUTOFS4_FS) += autofs4.o
+
+autofs4-objs := init.o inode.o root.o symlink.o waitq.o expire.o

fs/autofs4/autofs_i.h

@@ -0,0 +1,193 @@
+/* -*- c -*- ------------------------------------------------------------- *
+ *   
+ * linux/fs/autofs/autofs_i.h
+ *
+ *   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.
+ *
+ * ----------------------------------------------------------------------- */
+
+/* Internal header file for autofs */
+
+#include <linux/auto_fs4.h>
+#include <linux/list.h>
+
+/* This is the range of ioctl() numbers we claim as ours */
+#define AUTOFS_IOC_FIRST     AUTOFS_IOC_READY
+#define AUTOFS_IOC_COUNT     32
+
+#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 <asm/current.h>
+#include <asm/uaccess.h>
+
+/* #define DEBUG */
+
+#ifdef DEBUG
+#define DPRINTK(fmt,args...) do { printk(KERN_DEBUG "pid %d: %s: " fmt "\n" , current->pid , __FUNCTION__ , ##args); } while(0)
+#else
+#define DPRINTK(fmt,args...) do {} while(0)
+#endif
+
+#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
+   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 autofs_sb_info *sbi;
+	unsigned long last_used;
+
+	mode_t	mode;
+	size_t	size;
+
+	void (*free)(struct autofs_info *);
+	union {
+		const char *symlink;
+	} u;
+};
+
+#define AUTOFS_INF_EXPIRING	(1<<0) /* dentry is in the process of expiring */
+
+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 */
+	int hash;
+	int len;
+	char *name;
+	/* This is for status reporting upon return */
+	int status;
+	atomic_t wait_ctr;
+};
+
+#define AUTOFS_SBI_MAGIC 0x6d4a556d
+
+struct autofs_sb_info {
+	u32 magic;
+	struct file *pipe;
+	pid_t oz_pgrp;
+	int catatonic;
+	int version;
+	int sub_version;
+	unsigned long exp_timeout;
+	int reghost_enabled;
+	int needs_reghost;
+	struct super_block *sb;
+	struct semaphore wq_sem;
+	struct autofs_wait_queue *queues; /* Wait queue pointer */
+};
+
+static inline struct autofs_sb_info *autofs4_sbi(struct super_block *sb)
+{
+	return (struct autofs_sb_info *)(sb->s_fs_info);
+}
+
+static inline struct autofs_info *autofs4_dentry_ino(struct dentry *dentry)
+{
+	return (struct autofs_info *)(dentry->d_fsdata);
+}
+
+/* autofs4_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 autofs4_oz_mode(struct autofs_sb_info *sbi) {
+	return sbi->catatonic || process_group(current) == sbi->oz_pgrp;
+}
+
+/* Does a dentry have some pending activity? */
+static inline int autofs4_ispending(struct dentry *dentry)
+{
+	struct autofs_info *inf = autofs4_dentry_ino(dentry);
+
+	return (dentry->d_flags & DCACHE_AUTOFS_PENDING) ||
+		(inf != NULL && inf->flags & AUTOFS_INF_EXPIRING);
+}
+
+static inline void autofs4_copy_atime(struct file *src, struct file *dst)
+{
+	dst->f_dentry->d_inode->i_atime = src->f_dentry->d_inode->i_atime;
+	return;
+}
+
+struct inode *autofs4_get_inode(struct super_block *, struct autofs_info *);
+void autofs4_free_ino(struct autofs_info *);
+
+/* Expiration */
+int is_autofs4_dentry(struct dentry *);
+int autofs4_expire_run(struct super_block *, struct vfsmount *,
+			struct autofs_sb_info *,
+			struct autofs_packet_expire __user *);
+int autofs4_expire_multi(struct super_block *, struct vfsmount *,
+			struct autofs_sb_info *, int __user *);
+
+/* Operations structures */
+
+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;
+
+/* Initializing function */
+
+int autofs4_fill_super(struct super_block *, void *, int);
+struct autofs_info *autofs4_init_ino(struct autofs_info *, struct autofs_sb_info *sbi, mode_t mode);
+
+/* 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 *);
+
+static inline int simple_positive(struct dentry *dentry)
+{
+	return dentry->d_inode && !d_unhashed(dentry);
+}
+
+static inline int simple_empty_nolock(struct dentry *dentry)
+{
+	struct dentry *child;
+	int ret = 0;
+
+	list_for_each_entry(child, &dentry->d_subdirs, d_child)
+		if (simple_positive(child))
+			goto out;
+	ret = 1;
+out:
+	return ret;
+}

fs/autofs4/expire.c

@@ -0,0 +1,358 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/fs/autofs/expire.c
+ *
+ *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
+ *  Copyright 2001-2003 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 return 1 if it can else return 0 */
+static inline int autofs4_can_expire(struct dentry *dentry,
+					unsigned long timeout, int do_now)
+{
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+
+	/* dentry in the process of being deleted */
+	if (ino == NULL)
+		return 0;
+
+	/* No point expiring a pending mount */
+	if (dentry->d_flags & DCACHE_AUTOFS_PENDING)
+		return 0;
+
+	if (!do_now) {
+		/* Too young to die */
+		if (time_after(ino->last_used + timeout, now))
+			return 0;
+
+		/* update last_used here :-
+		   - obviously makes sense if it is in use now
+		   - less obviously, prevents rapid-fire expire
+		     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)
+{
+	int status = 0;
+
+	DPRINTK("dentry %p %.*s",
+		dentry, (int)dentry->d_name.len, dentry->d_name.name);
+
+	mntget(mnt);
+	dget(dentry);
+
+	if (!follow_down(&mnt, &dentry))
+		goto done;
+
+	while (d_mountpoint(dentry) && follow_down(&mnt, &dentry))
+		;
+
+	/* This is an autofs submount, we can't expire it */
+	if (is_autofs4_dentry(dentry))
+		goto done;
+
+	/* The big question */
+	if (may_umount_tree(mnt) == 0)
+		status = 1;
+done:
+	DPRINTK("returning = %d", status);
+	mntput(mnt);
+	dput(dentry);
+	return status;
+}
+
+/* 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)
+{
+	struct dentry *this_parent = top;
+	struct list_head *next;
+
+	DPRINTK("parent %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;
+
+	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_child);
+
+		/* Negative dentry - give up */
+		if (!simple_positive(dentry)) {
+			next = next->next;
+			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;
+		}
+
+		dentry = dget(dentry);
+		spin_unlock(&dcache_lock);
+
+		if (d_mountpoint(dentry)) {
+			/* First busy => tree busy */
+			if (!autofs4_check_mount(mnt, dentry)) {
+				dput(dentry);
+				return 0;
+			}
+		}
+
+		dput(dentry);
+		spin_lock(&dcache_lock);
+		next = next->next;
+	}
+
+	if (this_parent != top) {
+		next = this_parent->d_child.next;
+		this_parent = this_parent->d_parent;
+		goto resume;
+	}
+	spin_unlock(&dcache_lock);
+
+	return 1;
+}
+
+static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
+					   struct dentry *parent,
+					   unsigned long timeout,
+					   int do_now)
+{
+	struct dentry *this_parent = parent;
+	struct list_head *next;
+
+	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_child);
+
+		/* Negative dentry - give up */
+		if (!simple_positive(dentry)) {
+			next = next->next;
+			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;
+		}
+
+		dentry = dget(dentry);
+		spin_unlock(&dcache_lock);
+
+		if (d_mountpoint(dentry)) {
+			/* Can we expire this guy */
+			if (!autofs4_can_expire(dentry, timeout, do_now))
+				goto cont;
+
+			/* Can we umount this guy */
+			if (autofs4_check_mount(mnt, dentry))
+				return dentry;
+
+		}
+cont:
+		dput(dentry);
+		spin_lock(&dcache_lock);
+		next = next->next;
+	}
+
+	if (this_parent != parent) {
+		next = this_parent->d_child.next;
+		this_parent = this_parent->d_parent;
+		goto resume;
+	}
+	spin_unlock(&dcache_lock);
+
+	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
+ */
+static struct dentry *autofs4_expire(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 *expired = NULL;
+	struct list_head *next;
+	int do_now = how & AUTOFS_EXP_IMMEDIATE;
+	int exp_leaves = how & AUTOFS_EXP_LEAVES;
+
+	if ( !sbi->exp_timeout || !root )
+		return NULL;
+
+	now = jiffies;
+	timeout = sbi->exp_timeout;
+
+	spin_lock(&dcache_lock);
+	next = root->d_subdirs.next;
+
+	/* On exit from the loop expire is set to a dgot dentry
+	 * to expire or it's NULL */
+	while ( next != &root->d_subdirs ) {
+		struct dentry *dentry = list_entry(next, struct dentry, d_child);
+
+		/* Negative dentry - give up */
+		if ( !simple_positive(dentry) ) {
+			next = next->next;
+			continue;
+		}
+
+		dentry = dget(dentry);
+		spin_unlock(&dcache_lock);
+
+		/* Case 1: indirect mount or top level direct mount */
+		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))
+				goto next;
+
+			/* Can we umount this guy */
+			if (autofs4_check_mount(mnt, dentry)) {
+				expired = dentry;
+				break;
+			}
+			goto next;
+		}
+
+		if ( simple_empty(dentry) )
+			goto next;
+
+		/* Case 2: tree mount, expire iff entire tree is not busy */
+		if (!exp_leaves) {
+			if (autofs4_check_tree(mnt, dentry, timeout, do_now)) {
+			expired = dentry;
+			break;
+			}
+		/* Case 3: direct mount, expire individual leaves */
+		} else {
+			expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
+			if (expired) {
+				dput(dentry);
+				break;
+			}
+		}
+next:
+		dput(dentry);
+		spin_lock(&dcache_lock);
+		next = next->next;
+	}
+
+	if ( expired ) {
+		DPRINTK("returning %p %.*s",
+			expired, (int)expired->d_name.len, expired->d_name.name);
+		spin_lock(&dcache_lock);
+		list_del(&expired->d_parent->d_subdirs);
+		list_add(&expired->d_parent->d_subdirs, &expired->d_child);
+		spin_unlock(&dcache_lock);
+		return expired;
+	}
+	spin_unlock(&dcache_lock);
+
+	return NULL;
+}
+
+/* Perform an expiry operation */
+int autofs4_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 dentry *dentry;
+
+	memset(&pkt,0,sizeof pkt);
+
+	pkt.hdr.proto_version = sbi->version;
+	pkt.hdr.type = autofs_ptype_expire;
+
+	if ((dentry = autofs4_expire(sb, mnt, sbi, 0)) == NULL)
+		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)) )
+		return -EFAULT;
+
+	return 0;
+}
+
+/* Call repeatedly until it returns -EAGAIN, meaning there's nothing
+   more to be done */
+int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
+			struct autofs_sb_info *sbi, int __user *arg)
+{
+	struct dentry *dentry;
+	int ret = -EAGAIN;
+	int do_now = 0;
+
+	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);
+
+		/* This is synchronous because it makes the daemon a
+                   little easier */
+		de_info->flags |= AUTOFS_INF_EXPIRING;
+		ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
+		de_info->flags &= ~AUTOFS_INF_EXPIRING;
+		dput(dentry);
+	}
+		
+	return ret;
+}
+

fs/autofs4/init.c

@@ -0,0 +1,42 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/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 super_block *autofs_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return get_sb_nodev(fs_type, flags, data, autofs4_fill_super);
+}
+
+static struct file_system_type autofs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "autofs",
+	.get_sb		= autofs_get_sb,
+	.kill_sb	= kill_anon_super,
+};
+
+static int __init init_autofs4_fs(void)
+{
+	return register_filesystem(&autofs_fs_type);
+}
+
+static void __exit exit_autofs4_fs(void)
+{
+	unregister_filesystem(&autofs_fs_type);
+}
+
+module_init(init_autofs4_fs) 
+module_exit(exit_autofs4_fs)
+MODULE_LICENSE("GPL");

fs/autofs4/inode.c

@@ -0,0 +1,324 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/fs/autofs/inode.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/kernel.h>
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/pagemap.h>
+#include <linux/parser.h>
+#include <linux/bitops.h>
+#include "autofs_i.h"
+#include <linux/module.h>
+
+static void ino_lnkfree(struct autofs_info *ino)
+{
+	if (ino->u.symlink) {
+		kfree(ino->u.symlink);
+		ino->u.symlink = NULL;
+	}
+}
+
+struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
+				     struct autofs_sb_info *sbi, mode_t mode)
+{
+	int reinit = 1;
+
+	if (ino == NULL) {
+		reinit = 0;
+		ino = kmalloc(sizeof(*ino), GFP_KERNEL);
+	}
+
+	if (ino == NULL)
+		return NULL;
+
+	ino->flags = 0;
+	ino->mode = mode;
+	ino->inode = NULL;
+	ino->dentry = NULL;
+	ino->size = 0;
+
+	ino->last_used = jiffies;
+
+	ino->sbi = sbi;
+
+	if (reinit && ino->free)
+		(ino->free)(ino);
+
+	memset(&ino->u, 0, sizeof(ino->u));
+
+	ino->free = NULL;
+
+	if (S_ISLNK(mode))
+		ino->free = ino_lnkfree;
+
+	return ino;
+}
+
+void autofs4_free_ino(struct autofs_info *ino)
+{
+	if (ino->dentry) {
+		ino->dentry->d_fsdata = NULL;
+		if (ino->dentry->d_inode)
+			dput(ino->dentry);
+		ino->dentry = NULL;
+	}
+	if (ino->free)
+		(ino->free)(ino);
+	kfree(ino);
+}
+
+static void autofs4_put_super(struct super_block *sb)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(sb);
+
+	sb->s_fs_info = NULL;
+
+	if ( !sbi->catatonic )
+		autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
+
+	kfree(sbi);
+
+	DPRINTK("shutting down");
+}
+
+static struct super_operations autofs4_sops = {
+	.put_super	= autofs4_put_super,
+	.statfs		= simple_statfs,
+};
+
+enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};
+
+static 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_err, NULL}
+};
+
+static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
+			 pid_t *pgrp, int *minproto, int *maxproto)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+
+	*uid = current->uid;
+	*gid = current->gid;
+	*pgrp = process_group(current);
+
+	*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 = option;
+			break;
+		case Opt_gid:
+			if (match_int(args, &option))
+				return 1;
+			*gid = option;
+			break;
+		case Opt_pgrp:
+			if (match_int(args, &option))
+				return 1;
+			*pgrp = option;
+			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;
+		default:
+			return 1;
+		}
+	}
+	return (*pipefd < 0);
+}
+
+static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
+{
+	struct autofs_info *ino;
+
+	ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
+	if (!ino)
+		return NULL;
+
+	return ino;
+}
+
+int autofs4_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 minproto, maxproto;
+
+	sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
+	if ( !sbi )
+		goto fail_unlock;
+	DPRINTK("starting up, sbi = %p",sbi);
+
+	memset(sbi, 0, sizeof(*sbi));
+
+	s->s_fs_info = sbi;
+	sbi->magic = AUTOFS_SBI_MAGIC;
+	sbi->catatonic = 0;
+	sbi->exp_timeout = 0;
+	sbi->oz_pgrp = process_group(current);
+	sbi->sb = s;
+	sbi->version = 0;
+	sbi->sub_version = 0;
+	init_MUTEX(&sbi->wq_sem);
+	sbi->queues = NULL;
+	s->s_blocksize = 1024;
+	s->s_blocksize_bits = 10;
+	s->s_magic = AUTOFS_SUPER_MAGIC;
+	s->s_op = &autofs4_sops;
+	s->s_time_gran = 1;
+
+	/*
+	 * Get the root inode and dentry, but defer checking for errors.
+	 */
+	ino = autofs4_mkroot(sbi);
+	if (!ino)
+		goto fail_free;
+	root_inode = autofs4_get_inode(s, ino);
+	kfree(ino);
+	if (!root_inode)
+		goto fail_free;
+
+	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;
+
+	/* Can this call block? */
+	if (parse_options(data, &pipefd,
+			  &root_inode->i_uid, &root_inode->i_gid,
+			  &sbi->oz_pgrp,
+			  &minproto, &maxproto)) {
+		printk("autofs: called with bogus options\n");
+		goto fail_dput;
+	}
+
+	/* Couldn't this be tested earlier? */
+	if (maxproto < AUTOFS_MIN_PROTO_VERSION ||
+	    minproto > AUTOFS_MAX_PROTO_VERSION) {
+		printk("autofs: kernel does not match daemon version "
+		       "daemon (%d, %d) kernel (%d, %d)\n",
+			minproto, maxproto,
+			AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
+		goto fail_dput;
+	}
+
+	sbi->version = maxproto > AUTOFS_MAX_PROTO_VERSION ? AUTOFS_MAX_PROTO_VERSION : maxproto;
+	sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
+
+	DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
+	pipe = fget(pipefd);
+	
+	if ( !pipe ) {
+		printk("autofs: could not open pipe file descriptor\n");
+		goto fail_dput;
+	}
+	if ( !pipe->f_op || !pipe->f_op->write )
+		goto fail_fput;
+	sbi->pipe = pipe;
+
+	/*
+	 * Success! Install the root dentry now to indicate completion.
+	 */
+	s->s_root = root;
+	return 0;
+	
+	/*
+	 * Failure ... clean up.
+	 */
+fail_fput:
+	printk("autofs: pipe file descriptor does not contain proper ops\n");
+	fput(pipe);
+	/* fall through */
+fail_dput:
+	dput(root);
+	goto fail_free;
+fail_iput:
+	printk("autofs: get root dentry failed\n");
+	iput(root_inode);
+fail_free:
+	kfree(sbi);
+fail_unlock:
+	return -EINVAL;
+}
+
+struct inode *autofs4_get_inode(struct super_block *sb,
+				struct autofs_info *inf)
+{
+	struct inode *inode = new_inode(sb);
+
+	if (inode == NULL)
+		return NULL;
+
+	inf->inode = inode;
+	inode->i_mode = inf->mode;
+	if (sb->s_root) {
+		inode->i_uid = sb->s_root->d_inode->i_uid;
+		inode->i_gid = sb->s_root->d_inode->i_gid;
+	} else {
+		inode->i_uid = 0;
+		inode->i_gid = 0;
+	}
+	inode->i_blksize = PAGE_CACHE_SIZE;
+	inode->i_blocks = 0;
+	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+
+	if (S_ISDIR(inf->mode)) {
+		inode->i_nlink = 2;
+		inode->i_op = &autofs4_dir_inode_operations;
+		inode->i_fop = &autofs4_dir_operations;
+	} else if (S_ISLNK(inf->mode)) {
+		inode->i_size = inf->size;
+		inode->i_op = &autofs4_symlink_inode_operations;
+	}
+
+	return inode;
+}

fs/autofs4/root.c

@@ -0,0 +1,808 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/fs/autofs/root.c
+ *
+ *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
+ *  Copyright 2001-2003 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/errno.h>
+#include <linux/stat.h>
+#include <linux/param.h>
+#include <linux/time.h>
+#include <linux/smp_lock.h>
+#include "autofs_i.h"
+
+static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
+static int autofs4_dir_unlink(struct inode *,struct dentry *);
+static int autofs4_dir_rmdir(struct inode *,struct dentry *);
+static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
+static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
+static int autofs4_dir_open(struct inode *inode, struct file *file);
+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);
+
+struct file_operations autofs4_root_operations = {
+	.open		= dcache_dir_open,
+	.release	= dcache_dir_close,
+	.read		= generic_read_dir,
+	.readdir	= autofs4_root_readdir,
+	.ioctl		= autofs4_root_ioctl,
+};
+
+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 = {
+	.lookup		= autofs4_lookup,
+	.unlink		= autofs4_dir_unlink,
+	.symlink	= autofs4_dir_symlink,
+	.mkdir		= autofs4_dir_mkdir,
+	.rmdir		= autofs4_dir_rmdir,
+};
+
+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,
+};
+
+static int autofs4_root_readdir(struct file *file, void *dirent,
+				filldir_t filldir)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb);
+	int oz_mode = autofs4_oz_mode(sbi);
+
+	DPRINTK("called, filp->f_pos = %lld", file->f_pos);
+
+	/*
+	 * Don't set reghost flag if:
+	 * 1) f_pos is larger than zero -- we've already been here.
+	 * 2) we haven't even enabled reghosting in the 1st place.
+	 * 3) this is the daemon doing a readdir
+	 */
+	if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
+		sbi->needs_reghost = 1;
+
+	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 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) {
+			update_atime(dentry->d_inode);
+			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_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;
+}
+
+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);
+	int status;
+
+	DPRINTK("file=%p dentry=%p %.*s",
+		file, dentry, dentry->d_name.len, dentry->d_name.name);
+
+	if (autofs4_oz_mode(sbi))
+		goto out;
+
+	if (autofs4_ispending(dentry)) {
+		DPRINTK("dentry busy");
+		return -EBUSY;
+	}
+
+	if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
+		struct nameidata nd;
+		int empty;
+
+		/* In case there are stale directory dentrys from a failed mount */
+		spin_lock(&dcache_lock);
+		empty = list_empty(&dentry->d_subdirs);
+		spin_unlock(&dcache_lock);
+
+		if (!empty)
+			d_invalidate(dentry);
+
+		nd.flags = LOOKUP_DIRECTORY;
+		status = (dentry->d_op->d_revalidate)(dentry, &nd);
+
+		if (!status)
+			return -ENOENT;
+	}
+
+	if (d_mountpoint(dentry)) {
+		struct file *fp = NULL;
+		struct vfsmount *fp_mnt = mntget(mnt);
+		struct dentry *fp_dentry = dget(dentry);
+
+		while (follow_down(&fp_mnt, &fp_dentry) && d_mountpoint(fp_dentry));
+
+		fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
+		status = PTR_ERR(fp);
+		if (IS_ERR(fp)) {
+			file->private_data = NULL;
+			return status;
+		}
+		file->private_data = fp;
+	}
+out:
+	return 0;
+}
+
+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);
+
+	DPRINTK("file=%p dentry=%p %.*s",
+		file, dentry, dentry->d_name.len, dentry->d_name.name);
+
+	if (autofs4_oz_mode(sbi))
+		goto out;
+
+	if (autofs4_ispending(dentry)) {
+		DPRINTK("dentry busy");
+		return -EBUSY;
+	}
+
+	if (d_mountpoint(dentry)) {
+		struct file *fp = file->private_data;
+
+		if (!fp)
+			return -ENOENT;
+
+		filp_close(fp, current->files);
+		file->private_data = NULL;
+	}
+out:
+	return 0;
+}
+
+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);
+	int status;
+
+	DPRINTK("file=%p dentry=%p %.*s",
+		file, dentry, dentry->d_name.len, dentry->d_name.name);
+
+	if (autofs4_oz_mode(sbi))
+		goto out;
+
+	if (autofs4_ispending(dentry)) {
+		DPRINTK("dentry busy");
+		return -EBUSY;
+	}
+
+	if (d_mountpoint(dentry)) {
+		struct file *fp = file->private_data;
+
+		if (!fp)
+			return -ENOENT;
+
+		if (!fp->f_op || !fp->f_op->readdir)
+			goto out;
+
+		status = vfs_readdir(fp, filldir, dirent);
+		file->f_pos = fp->f_pos;
+		if (status)
+			autofs4_copy_atime(file, fp);
+		return status;
+	}
+out:
+	return autofs4_dcache_readdir(file, dirent, filldir);
+}
+
+static int try_to_fill_dentry(struct dentry *dentry, 
+			      struct super_block *sb,
+			      struct autofs_sb_info *sbi, int flags)
+{
+	struct autofs_info *de_info = autofs4_dentry_ino(dentry);
+	int status = 0;
+
+	/* Block on any pending expiry here; invalidate the dentry
+           when expiration is done to trigger mount request with a new
+           dentry */
+	if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
+		DPRINTK("waiting for expire %p name=%.*s",
+			 dentry, dentry->d_name.len, dentry->d_name.name);
+
+		status = autofs4_wait(sbi, dentry, NFY_NONE);
+		
+		DPRINTK("expire done status=%d", status);
+		
+		return 0;
+	}
+
+	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);
+
+		if (status && dentry->d_inode)
+			return 0; /* Try to get the kernel to invalidate this dentry */
+		
+		/* Turn this into a real negative dentry? */
+		if (status == -ENOENT) {
+			dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
+			spin_lock(&dentry->d_lock);
+			dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
+			spin_unlock(&dentry->d_lock);
+			return 1;
+		} else if (status) {
+			/* Return a negative dentry, but leave it "pending" */
+			return 1;
+		}
+	/* Trigger mount for path component or follow link */
+	} else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
+			current->link_count) {
+		DPRINTK("waiting for mount name=%.*s",
+			dentry->d_name.len, dentry->d_name.name);
+
+		spin_lock(&dentry->d_lock);
+		dentry->d_flags |= DCACHE_AUTOFS_PENDING;
+		spin_unlock(&dentry->d_lock);
+		status = autofs4_wait(sbi, dentry, NFY_MOUNT);
+
+		DPRINTK("mount done status=%d", status);
+
+		if (status) {
+			spin_lock(&dentry->d_lock);
+			dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
+			spin_unlock(&dentry->d_lock);
+			return 0;
+		}
+	}
+
+	/* We don't update the usages for the autofs daemon itself, this
+	   is necessary for recursive autofs mounts */
+	if (!autofs4_oz_mode(sbi))
+		autofs4_update_usage(dentry);
+
+	spin_lock(&dentry->d_lock);
+	dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
+	spin_unlock(&dentry->d_lock);
+	return 1;
+}
+
+/*
+ * 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)
+{
+	struct inode * dir = dentry->d_parent->d_inode;
+	struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
+	int oz_mode = autofs4_oz_mode(sbi);
+	int flags = nd ? nd->flags : 0;
+	int status = 1;
+
+	/* Pending dentry */
+	if (autofs4_ispending(dentry)) {
+		if (!oz_mode)
+			status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags);
+		return status;
+	}
+
+	/* Negative dentry.. invalidate if "old" */
+	if (dentry->d_inode == NULL)
+		return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
+
+	/* Check for a non-mountpoint directory with no contents */
+	spin_lock(&dcache_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(&dcache_lock);
+		if (!oz_mode)
+			status = try_to_fill_dentry(dentry, dir->i_sb, sbi, flags);
+		return status;
+	}
+	spin_unlock(&dcache_lock);
+
+	/* Update the usage list */
+	if (!oz_mode)
+		autofs4_update_usage(dentry);
+
+	return 1;
+}
+
+static void autofs4_dentry_release(struct dentry *de)
+{
+	struct autofs_info *inf;
+
+	DPRINTK("releasing %p", de);
+
+	inf = autofs4_dentry_ino(de);
+	de->d_fsdata = NULL;
+
+	if (inf) {
+		inf->dentry = NULL;
+		inf->inode = NULL;
+
+		autofs4_free_ino(inf);
+	}
+}
+
+/* For dentries of directories in the root dir */
+static struct dentry_operations autofs4_root_dentry_operations = {
+	.d_revalidate	= autofs4_revalidate,
+	.d_release	= autofs4_dentry_release,
+};
+
+/* For other dentries */
+static struct dentry_operations autofs4_dentry_operations = {
+	.d_revalidate	= autofs4_revalidate,
+	.d_release	= autofs4_dentry_release,
+};
+
+/* Lookups in the root directory */
+static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+	struct autofs_sb_info *sbi;
+	int oz_mode;
+
+	DPRINTK("name = %.*s",
+		dentry->d_name.len, dentry->d_name.name);
+
+	if (dentry->d_name.len > NAME_MAX)
+		return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
+
+	sbi = autofs4_sbi(dir->i_sb);
+
+	oz_mode = autofs4_oz_mode(sbi);
+	DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
+		 current->pid, process_group(current), sbi->catatonic, oz_mode);
+
+	/*
+	 * Mark the dentry incomplete, but add it. This is needed so
+	 * that the VFS layer knows about the dentry, and we can count
+	 * on catching any lookups through the revalidate.
+	 *
+	 * Let all the hard work be done by the revalidate function that
+	 * needs to be able to do this anyway..
+	 *
+	 * We need to do this before we release the directory semaphore.
+	 */
+	dentry->d_op = &autofs4_root_dentry_operations;
+
+	if (!oz_mode) {
+		spin_lock(&dentry->d_lock);
+		dentry->d_flags |= DCACHE_AUTOFS_PENDING;
+		spin_unlock(&dentry->d_lock);
+	}
+	dentry->d_fsdata = NULL;
+	d_add(dentry, NULL);
+
+	if (dentry->d_op && dentry->d_op->d_revalidate) {
+		up(&dir->i_sem);
+		(dentry->d_op->d_revalidate)(dentry, nd);
+		down(&dir->i_sem);
+	}
+
+	/*
+	 * If we are still pending, check if we had to handle
+	 * a signal. If so we can force a restart..
+	 */
+	if (dentry->d_flags & DCACHE_AUTOFS_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)) {
+			    return ERR_PTR(-ERESTARTNOINTR);
+			}
+		}
+	}
+
+	/*
+	 * If this dentry is unhashed, then we shouldn't honour this
+	 * lookup even if the dentry is positive.  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 ( dentry->d_inode && d_unhashed(dentry) )
+		return ERR_PTR(-ENOENT);
+
+	return NULL;
+}
+
+static int autofs4_dir_symlink(struct inode *dir, 
+			       struct dentry *dentry,
+			       const char *symname)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	struct inode *inode;
+	char *cp;
+
+	DPRINTK("%s <- %.*s", symname,
+		dentry->d_name.len, dentry->d_name.name);
+
+	if (!autofs4_oz_mode(sbi))
+		return -EACCES;
+
+	ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
+	if (ino == NULL)
+		return -ENOSPC;
+
+	ino->size = strlen(symname);
+	ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
+
+	if (cp == NULL) {
+		kfree(ino);
+		return -ENOSPC;
+	}
+
+	strcpy(cp, symname);
+
+	inode = autofs4_get_inode(dir->i_sb, ino);
+	d_instantiate(dentry, inode);
+
+	if (dir == dir->i_sb->s_root->d_inode)
+		dentry->d_op = &autofs4_root_dentry_operations;
+	else
+		dentry->d_op = &autofs4_dentry_operations;
+
+	dentry->d_fsdata = ino;
+	ino->dentry = dget(dentry);
+	ino->inode = inode;
+
+	dir->i_mtime = CURRENT_TIME;
+
+	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 since the unlink is probably the result of an expire.
+ * We simply d_drop it, which allows the dentry lookup to remount it
+ * if necessary.
+ *
+ * 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 autofs4_dir_rmdir()..
+ */
+static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	
+	/* This allows root to remove symlinks */
+	if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
+		return -EACCES;
+
+	dput(ino->dentry);
+
+	dentry->d_inode->i_size = 0;
+	dentry->d_inode->i_nlink = 0;
+
+	dir->i_mtime = CURRENT_TIME;
+
+	d_drop(dentry);
+
+	return 0;
+}
+
+static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	
+	if (!autofs4_oz_mode(sbi))
+		return -EACCES;
+
+	spin_lock(&dcache_lock);
+	if (!list_empty(&dentry->d_subdirs)) {
+		spin_unlock(&dcache_lock);
+		return -ENOTEMPTY;
+	}
+	spin_lock(&dentry->d_lock);
+	__d_drop(dentry);
+	spin_unlock(&dentry->d_lock);
+	spin_unlock(&dcache_lock);
+
+	dput(ino->dentry);
+
+	dentry->d_inode->i_size = 0;
+	dentry->d_inode->i_nlink = 0;
+
+	if (dir->i_nlink)
+		dir->i_nlink--;
+
+	return 0;
+}
+
+static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	struct inode *inode;
+
+	if ( !autofs4_oz_mode(sbi) )
+		return -EACCES;
+
+	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 == NULL)
+		return -ENOSPC;
+
+	inode = autofs4_get_inode(dir->i_sb, ino);
+	d_instantiate(dentry, inode);
+
+	if (dir == dir->i_sb->s_root->d_inode)
+		dentry->d_op = &autofs4_root_dentry_operations;
+	else
+		dentry->d_op = &autofs4_dentry_operations;
+
+	dentry->d_fsdata = ino;
+	ino->dentry = dget(dentry);
+	ino->inode = inode;
+	dir->i_nlink++;
+	dir->i_mtime = CURRENT_TIME;
+
+	return 0;
+}
+
+/* Get/set timeout ioctl() operation */
+static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
+					 unsigned long __user *p)
+{
+	int rv;
+	unsigned long ntimeout;
+
+	if ( (rv = get_user(ntimeout, p)) ||
+	     (rv = put_user(sbi->exp_timeout/HZ, p)) )
+		return rv;
+
+	if ( ntimeout > ULONG_MAX/HZ )
+		sbi->exp_timeout = 0;
+	else
+		sbi->exp_timeout = ntimeout * HZ;
+
+	return 0;
+}
+
+/* Return protocol version */
+static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
+{
+	return put_user(sbi->version, p);
+}
+
+/* Return protocol sub version */
+static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
+{
+	return put_user(sbi->sub_version, p);
+}
+
+/*
+ * Tells the daemon whether we need to reghost or not. Also, clears
+ * the reghost_needed flag.
+ */
+static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
+{
+	int status;
+
+	DPRINTK("returning %d", sbi->needs_reghost);
+
+	status = put_user(sbi->needs_reghost, p);
+	if ( status )
+		return status;
+
+	sbi->needs_reghost = 0;
+	return 0;
+}
+
+/*
+ * Enable / Disable reghosting ioctl() operation
+ */
+static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
+{
+	int status;
+	int val;
+
+	status = get_user(val, p);
+
+	DPRINTK("reghost = %d", val);
+
+	if (status)
+		return status;
+
+	/* turn on/off reghosting, with the val */
+	sbi->reghost_enabled = val;
+	return 0;
+}
+
+/*
+* Tells the daemon whether it can umount the autofs mount.
+*/
+static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
+{
+	int status = 0;
+
+	if (may_umount(mnt) == 0)
+		status = 1;
+
+	DPRINTK("returning %d", status);
+
+	status = put_user(status, p);
+
+	return status;
+}
+
+/* Identify autofs4_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_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_fsdata != NULL;
+}
+
+/*
+ * ioctl()'s on the root directory is the chief method for the daemon to
+ * generate kernel reactions
+ */
+static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
+			     unsigned int cmd, unsigned long arg)
+{
+	struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
+	void __user *p = (void __user *)arg;
+
+	DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
+		cmd,arg,sbi,process_group(current));
+
+	if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
+	     _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
+		return -ENOTTY;
+	
+	if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
+		return -EPERM;
+	
+	switch(cmd) {
+	case AUTOFS_IOC_READY:	/* Wait queue: go ahead and retry */
+		return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
+	case AUTOFS_IOC_FAIL:	/* Wait queue: fail with ENOENT */
+		return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
+	case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
+		autofs4_catatonic_mode(sbi);
+		return 0;
+	case AUTOFS_IOC_PROTOVER: /* Get protocol version */
+		return autofs4_get_protover(sbi, p);
+	case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
+		return autofs4_get_protosubver(sbi, p);
+	case AUTOFS_IOC_SETTIMEOUT:
+		return autofs4_get_set_timeout(sbi, p);
+
+	case AUTOFS_IOC_TOGGLEREGHOST:
+		return autofs4_toggle_reghost(sbi, p);
+	case AUTOFS_IOC_ASKREGHOST:
+		return autofs4_ask_reghost(sbi, p);
+
+	case AUTOFS_IOC_ASKUMOUNT:
+		return autofs4_ask_umount(filp->f_vfsmnt, p);
+
+	/* return a single thing to expire */
+	case AUTOFS_IOC_EXPIRE:
+		return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
+	/* same as above, but can send multiple expires through pipe */
+	case AUTOFS_IOC_EXPIRE_MULTI:
+		return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);
+
+	default:
+		return -ENOSYS;
+	}
+}

fs/autofs4/symlink.c

@@ -0,0 +1,25 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/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 int autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	nd_set_link(nd, (char *)ino->u.symlink);
+	return 0;
+}
+
+struct inode_operations autofs4_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= autofs4_follow_link
+};

fs/autofs4/waitq.c

@@ -0,0 +1,303 @@
+/* -*- c -*- --------------------------------------------------------------- *
+ *
+ * linux/fs/autofs/waitq.c
+ *
+ *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
+ *  Copyright 2001-2003 Ian Kent <raven@themaw.net>
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * ------------------------------------------------------------------------- */
+
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/signal.h>
+#include <linux/file.h>
+#include "autofs_i.h"
+
+/* We make this a static variable rather than a part of the superblock; it
+   is better if we don't reassign numbers easily even across filesystems */
+static autofs_wqt_t autofs4_next_wait_queue = 1;
+
+/* These are the signals we allow interrupting a pending mount */
+#define SHUTDOWN_SIGS	(sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
+
+void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
+{
+	struct autofs_wait_queue *wq, *nwq;
+
+	DPRINTK("entering catatonic mode");
+
+	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);
+		wq->name = NULL;
+		wake_up_interruptible(&wq->queue);
+		wq = nwq;
+	}
+	if (sbi->pipe) {
+		fput(sbi->pipe);	/* Close the pipe */
+		sbi->pipe = NULL;
+	}
+
+	shrink_dcache_sb(sbi->sb);
+}
+
+static int autofs4_write(struct file *file, const void *addr, int bytes)
+{
+	unsigned long sigpipe, flags;
+	mm_segment_t fs;
+	const char *data = (const char *)addr;
+	ssize_t wr = 0;
+
+	/** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/
+
+	sigpipe = sigismember(&current->pending.signal, SIGPIPE);
+
+	/* Save pointer to user space and point back to kernel space */
+	fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	while (bytes &&
+	       (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) {
+		data += wr;
+		bytes -= wr;
+	}
+
+	set_fs(fs);
+
+	/* Keep the currently executing process from receiving a
+	   SIGPIPE unless it was already supposed to get one */
+	if (wr == -EPIPE && !sigpipe) {
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		sigdelset(&current->pending.signal, SIGPIPE);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	}
+
+	return (bytes > 0);
+}
+	
+static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
+				 struct autofs_wait_queue *wq,
+				 int type)
+{
+	union autofs_packet_union pkt;
+	size_t pktsz;
+
+	DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d",
+		wq->wait_queue_token, wq->len, wq->name, type);
+
+	memset(&pkt,0,sizeof pkt); /* For security reasons */
+
+	pkt.hdr.proto_version = sbi->version;
+	pkt.hdr.type = type;
+	if (type == autofs_ptype_missing) {
+		struct autofs_packet_missing *mp = &pkt.missing;
+
+		pktsz = sizeof(*mp);
+
+		mp->wait_queue_token = wq->wait_queue_token;
+		mp->len = wq->len;
+		memcpy(mp->name, wq->name, wq->len);
+		mp->name[wq->len] = '\0';
+	} else if (type == autofs_ptype_expire_multi) {
+		struct autofs_packet_expire_multi *ep = &pkt.expire_multi;
+
+		pktsz = sizeof(*ep);
+
+		ep->wait_queue_token = wq->wait_queue_token;
+		ep->len = wq->len;
+		memcpy(ep->name, wq->name, wq->len);
+		ep->name[wq->len] = '\0';
+	} else {
+		printk("autofs4_notify_daemon: bad type %d!\n", type);
+		return;
+	}
+
+	if (autofs4_write(sbi->pipe, &pkt, pktsz))
+		autofs4_catatonic_mode(sbi);
+}
+
+static int autofs4_getpath(struct autofs_sb_info *sbi,
+			   struct dentry *dentry, char **name)
+{
+	struct dentry *root = sbi->sb->s_root;
+	struct dentry *tmp;
+	char *buf = *name;
+	char *p;
+	int len = 0;
+
+	spin_lock(&dcache_lock);
+	for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
+		len += tmp->d_name.len + 1;
+
+	if (--len > NAME_MAX) {
+		spin_unlock(&dcache_lock);
+		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(&dcache_lock);
+
+	return len;
+}
+
+int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry,
+		enum autofs_notify notify)
+{
+	struct autofs_wait_queue *wq;
+	char *name;
+	int len, status;
+
+	/* In catatonic mode, we don't wait for nobody */
+	if ( sbi->catatonic )
+		return -ENOENT;
+	
+	name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	len = autofs4_getpath(sbi, dentry, &name);
+	if (!len) {
+		kfree(name);
+		return -ENOENT;
+	}
+
+	if (down_interruptible(&sbi->wq_sem)) {
+		kfree(name);
+		return -EINTR;
+	}
+
+	for (wq = sbi->queues ; wq ; wq = wq->next) {
+		if (wq->hash == dentry->d_name.hash &&
+		    wq->len == len &&
+		    wq->name && !memcmp(wq->name, name, len))
+			break;
+	}
+
+	if ( !wq ) {
+		/* Create a new wait queue */
+		wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL);
+		if ( !wq ) {
+			kfree(name);
+			up(&sbi->wq_sem);
+			return -ENOMEM;
+		}
+
+		wq->wait_queue_token = autofs4_next_wait_queue;
+		if (++autofs4_next_wait_queue == 0)
+			autofs4_next_wait_queue = 1;
+		wq->next = sbi->queues;
+		sbi->queues = wq;
+		init_waitqueue_head(&wq->queue);
+		wq->hash = dentry->d_name.hash;
+		wq->name = name;
+		wq->len = len;
+		wq->status = -EINTR; /* Status return if interrupted */
+		atomic_set(&wq->wait_ctr, 2);
+		up(&sbi->wq_sem);
+
+		DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d",
+			(unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
+		/* autofs4_notify_daemon() may block */
+		if (notify != NFY_NONE) {
+			autofs4_notify_daemon(sbi,wq, 
+					notify == NFY_MOUNT ?
+						  autofs_ptype_missing :
+						  autofs_ptype_expire_multi);
+		}
+	} else {
+		atomic_inc(&wq->wait_ctr);
+		up(&sbi->wq_sem);
+		kfree(name);
+		DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d",
+			(unsigned long) wq->wait_queue_token, wq->len, wq->name, notify);
+	}
+
+	/* wq->name is NULL if and only if the lock is already released */
+
+	if ( sbi->catatonic ) {
+		/* We might have slept, so check again for catatonic mode */
+		wq->status = -ENOENT;
+		if ( wq->name ) {
+			kfree(wq->name);
+			wq->name = NULL;
+		}
+	}
+
+	if ( wq->name ) {
+		/* Block all but "shutdown" signals while waiting */
+		sigset_t oldset;
+		unsigned long irqflags;
+
+		spin_lock_irqsave(&current->sighand->siglock, irqflags);
+		oldset = current->blocked;
+		siginitsetinv(&current->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
+
+		wait_event_interruptible(wq->queue, wq->name == NULL);
+
+		spin_lock_irqsave(&current->sighand->siglock, irqflags);
+		current->blocked = oldset;
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, irqflags);
+	} else {
+		DPRINTK("skipped sleeping");
+	}
+
+	status = wq->status;
+
+	/* Are we the last process to need status? */
+	if (atomic_dec_and_test(&wq->wait_ctr))
+		kfree(wq);
+
+	return status;
+}
+
+
+int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
+{
+	struct autofs_wait_queue *wq, **wql;
+
+	down(&sbi->wq_sem);
+	for ( wql = &sbi->queues ; (wq = *wql) != 0 ; wql = &wq->next ) {
+		if ( wq->wait_queue_token == wait_queue_token )
+			break;
+	}
+
+	if ( !wq ) {
+		up(&sbi->wq_sem);
+		return -EINVAL;
+	}
+
+	*wql = wq->next;	/* Unlink from chain */
+	up(&sbi->wq_sem);
+	kfree(wq->name);
+	wq->name = NULL;	/* Do not wait on this queue */
+
+	wq->status = status;
+
+	if (atomic_dec_and_test(&wq->wait_ctr))	/* Is anyone still waiting for this guy? */
+		kfree(wq);
+	else
+		wake_up_interruptible(&wq->queue);
+
+	return 0;
+}
+