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/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;
+	}
+}