# This adds the externfs facility without any users.  It allows host resources
# to be plugged in and mounted as Linux filesystems.  It takes care of 
# interacting with the kernel, leaving the userspace modules to interact
# with whatever host resources they import.
Index: um/arch/um/Kconfig
===================================================================
--- um.orig/arch/um/Kconfig	2004-08-06 15:17:22.000000000 -0400
+++ um/arch/um/Kconfig	2004-08-06 16:41:00.000000000 -0400
@@ -78,6 +78,9 @@
 
 source "fs/Kconfig.binfmt"
 
+config EXTERNFS
+	tristate "Support for host-based filesystems"
+
 config HOSTFS
 	tristate "Host filesystem"
 	help
Index: um/fs/Makefile
===================================================================
--- um.orig/fs/Makefile	2004-08-06 15:17:22.000000000 -0400
+++ um/fs/Makefile	2004-08-06 15:17:25.000000000 -0400
@@ -91,5 +91,4 @@
 obj-$(CONFIG_XFS_FS)		+= xfs/
 obj-$(CONFIG_AFS_FS)		+= afs/
 obj-$(CONFIG_BEFS_FS)		+= befs/
-obj-$(CONFIG_HOSTFS)		+= hostfs/
-obj-$(CONFIG_HPPFS)		+= hppfs/
+obj-$(CONFIG_EXTERNFS)		+= hostfs/
Index: um/fs/hostfs/Makefile
===================================================================
--- um.orig/fs/hostfs/Makefile	2004-08-06 15:17:22.000000000 -0400
+++ um/fs/hostfs/Makefile	2004-08-07 12:07:32.000000000 -0400
@@ -3,24 +3,13 @@
 # Licensed under the GPL
 #
 
-# struct stat64 changed the inode field name between 2.2 and 2.4 from st_ino
-# to __st_ino.  It stayed in the same place, so as long as the correct name
-# is used, hostfs compiled on 2.2 should work on 2.4 and vice versa.
-
-STAT64_INO_FIELD := $(shell grep -q __st_ino /usr/include/bits/stat.h && \
-				echo __)st_ino
-
-hostfs-objs := hostfs_kern.o hostfs_user.o
-
 obj-y = 
-obj-$(CONFIG_HOSTFS) += hostfs.o
+obj-$(CONFIG_EXTERNFS) += externfs.o
 
 SINGLE_OBJS = $(foreach f,$(patsubst %.o,%,$(obj-y) $(obj-m)),$($(f)-objs))
 
 USER_OBJS := $(filter %_user.o,$(obj-y) $(obj-m) $(SINGLE_OBJS))
 USER_OBJS := $(foreach file,$(USER_OBJS),$(obj)/$(file))
 
-USER_CFLAGS += -DSTAT64_INO_FIELD=$(STAT64_INO_FIELD)
-
 $(USER_OBJS) : %.o: %.c
 	$(CC) $(CFLAGS_$(notdir $@)) $(USER_CFLAGS) -c -o $@ $<
Index: um/fs/hostfs/externfs.c
===================================================================
--- um.orig/fs/hostfs/externfs.c	2003-09-15 09:40:47.000000000 -0400
+++ um/fs/hostfs/externfs.c	2004-08-07 12:03:50.000000000 -0400
@@ -0,0 +1,1317 @@
+/* 
+ * Copyright (C) 2000 - 2004 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/stddef.h>
+#include <linux/fs.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/statfs.h>
+#include <asm/uaccess.h>
+#include "hostfs.h"
+#include "kern_util.h"
+#include "kern.h"
+#include "user_util.h"
+#include "2_5compat.h"
+#include "mem.h"
+#include "filehandle.h"
+
+struct externfs {
+	struct list_head list;
+	struct externfs_mount_ops *mount_ops;
+	struct file_system_type type;
+};
+
+static inline struct externfs_inode *EXTERNFS_I(struct inode *inode)
+{
+	return(container_of(inode, struct externfs_inode, vfs_inode));
+}
+
+#define file_externfs_i(file) EXTERNFS_I((file)->f_dentry->d_inode)
+
+int externfs_d_delete(struct dentry *dentry)
+{
+	return(1);
+}
+
+struct dentry_operations externfs_dentry_ops = {
+};
+
+#define EXTERNFS_SUPER_MAGIC 0x00c0ffee
+
+static struct inode_operations externfs_iops;
+static struct inode_operations externfs_dir_iops;
+static struct address_space_operations externfs_link_aops;
+
+static char *dentry_name(struct dentry *dentry, int extra)
+{
+	struct dentry *parent;
+	char *name;
+	int len;
+
+	len = 0;
+	parent = dentry;
+	while(parent->d_parent != parent){
+		len += parent->d_name.len + 1;
+		parent = parent->d_parent;
+	}
+	
+	name = kmalloc(len + extra + 1, GFP_KERNEL);
+	if(name == NULL) return(NULL);
+
+	name[len] = '\0';
+	parent = dentry;
+	while(parent->d_parent != parent){
+		len -= parent->d_name.len + 1;
+		name[len] = '/';
+		strncpy(&name[len + 1], parent->d_name.name, 
+			parent->d_name.len);
+		parent = parent->d_parent;
+	}
+
+	return(name);
+}
+
+char *inode_name(struct inode *ino, int extra)
+{
+	struct dentry *dentry;
+
+	dentry = list_entry(ino->i_dentry.next, struct dentry, d_alias);
+	return(dentry_name(dentry, extra));
+}
+
+char *inode_name_prefix(struct inode *inode, char *prefix)
+{
+	int len;
+	char *name;
+
+	len = strlen(prefix);
+	name = inode_name(inode, len);
+	if(name == NULL)
+		return(name);
+
+	memmove(&name[len], name, strlen(name) + 1);
+	memcpy(name, prefix, strlen(prefix));
+	return(name);
+}
+
+static int read_name(struct inode *ino, char *name)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	/* The non-int inode fields are copied into ints by stat_file and
+	 * then copied into the inode because passing the actual pointers
+	 * in and having them treated as int * breaks on big-endian machines
+	 */
+	dev_t i_rdev;
+	int err;
+	int i_mode, i_nlink, i_blksize;
+	unsigned long atime, mtime, ctime;
+	unsigned long long i_size;
+	unsigned long long i_ino;
+	unsigned long long i_blocks;
+
+	err = (*ops->stat_file)(name, ino->i_sb->s_fs_info, &i_rdev, &i_ino,
+				&i_mode, &i_nlink, &ino->i_uid, &ino->i_gid,
+				&i_size, &atime, &mtime, &ctime, &i_blksize, 
+				&i_blocks);
+	if(err) return(err);
+
+	ino->i_atime.tv_sec = atime;
+	ino->i_atime.tv_nsec = 0;
+	
+	ino->i_ctime.tv_sec = ctime;
+	ino->i_ctime.tv_nsec = 0;
+	
+	ino->i_mtime.tv_sec = mtime;
+	ino->i_mtime.tv_nsec = 0;
+
+	ino->i_ino = i_ino;
+	ino->i_rdev = i_rdev;
+	ino->i_mode = i_mode;
+	ino->i_nlink = i_nlink;
+	ino->i_size = i_size;
+	ino->i_blksize = i_blksize;
+	ino->i_blocks = i_blocks;
+	return(0);
+}
+
+static char *follow_link(char *link, 
+			 int (*do_read_link)(char *path, int uid, int gid,
+					     char *buf, int size, 
+					     struct externfs_data *ed),
+			 int uid, int gid, struct externfs_data *ed)
+{
+	int len, n;
+	char *name, *resolved, *end;
+
+	len = 64;
+	while(1){
+		n = -ENOMEM;
+		name = kmalloc(len, GFP_KERNEL);
+		if(name == NULL)
+			goto out;
+
+		n = (*do_read_link)(link, uid, gid, name, len, ed);
+		if(n < len)
+			break;
+		len *= 2;
+		kfree(name);
+	}
+	if(n < 0)
+		goto out_free;
+
+	if(*name == '/')
+		return(name);
+
+	end = strrchr(link, '/');
+	if(end == NULL)
+		return(name);
+
+	*(end + 1) = '\0';
+	len = strlen(link) + strlen(name) + 1;
+
+	resolved = kmalloc(len, GFP_KERNEL);
+	if(resolved == NULL){
+		n = -ENOMEM;
+		goto out_free;
+	}
+
+	sprintf(resolved, "%s%s", link, name);
+	kfree(name);
+	return(resolved);
+
+ out_free:
+	kfree(name);
+ out:
+	return(ERR_PTR(n));
+}
+
+static int read_inode(struct inode *ino)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *name, *new;
+	int err = 0, type;
+
+	/* Unfortunately, we are called from iget() when we don't have a dentry
+	 * allocated yet.
+	 */
+	if(list_empty(&ino->i_dentry))
+		goto out;
+ 
+	err = -ENOMEM;
+	name = inode_name(ino, 0);
+	if(name == NULL) 
+		goto out;
+
+	type = (*ops->file_type)(name, NULL, ed);
+	if(type < 0){
+		err = type;
+		goto out_free;
+	}
+
+	if(type == OS_TYPE_SYMLINK){
+		new = follow_link(name, ops->read_link, current->fsuid,
+				  current->fsgid, ed);
+		if(IS_ERR(new)){
+			err = PTR_ERR(new);
+			goto out_free;
+		}
+		kfree(name);
+		name = new;
+	}
+	
+	err = read_name(ino, name);
+ out_free:
+	kfree(name);
+ out:
+	return(err);
+}
+
+int externfs_statfs(struct super_block *sb, struct kstatfs *sf)
+{
+	/* do_statfs uses struct statfs64 internally, but the linux kernel
+	 * struct statfs still has 32-bit versions for most of these fields,
+	 * so we convert them here
+	 */
+	int err;
+	long long f_blocks;
+	long long f_bfree;
+	long long f_bavail;
+	long long f_files;
+	long long f_ffree;
+	struct externfs_data *ed = sb->s_fs_info;
+	
+	err = (*ed->file_ops->statfs)(&sf->f_bsize, &f_blocks, &f_bfree, 
+				      &f_bavail, &f_files, &f_ffree, 
+				      &sf->f_fsid, sizeof(sf->f_fsid), 
+				      &sf->f_namelen, sf->f_spare, ed);
+	if(err)
+		return(err);
+
+	sf->f_blocks = f_blocks;
+	sf->f_bfree = f_bfree;
+	sf->f_bavail = f_bavail;
+	sf->f_files = f_files;
+	sf->f_ffree = f_ffree;
+	sf->f_type = EXTERNFS_SUPER_MAGIC;
+	return(0);
+}
+
+static struct inode *externfs_alloc_inode(struct super_block *sb)
+{
+	struct externfs_data *ed = sb->s_fs_info;
+	struct externfs_inode *ext;
+
+	ext = (*ed->mount_ops->init_file)(ed);
+	if(ext == NULL) 
+		return(NULL);
+
+	*ext = ((struct externfs_inode) { .ops	= ed->file_ops });
+
+	inode_init_once(&ext->vfs_inode);
+	return(&ext->vfs_inode);
+}
+
+static void externfs_destroy_inode(struct inode *inode)
+{
+	struct externfs_inode *ext = EXTERNFS_I(inode);
+
+	(*ext->ops->close_file)(ext, inode->i_size);
+}
+
+static void externfs_read_inode(struct inode *inode)
+{
+	read_inode(inode);
+}
+
+static struct super_operations externfs_sbops = { 
+	.alloc_inode	= externfs_alloc_inode,
+	.destroy_inode	= externfs_destroy_inode,
+	.read_inode	= externfs_read_inode,
+	.statfs		= externfs_statfs,
+};
+
+int externfs_readdir(struct file *file, void *ent, filldir_t filldir)
+{
+	void *dir;
+	char *name;
+	unsigned long long next, ino;
+	int error, len;
+	struct externfs_file_ops *ops = file_externfs_i(file)->ops;
+	struct externfs_data *ed = file->f_dentry->d_inode->i_sb->s_fs_info;
+
+	name = dentry_name(file->f_dentry, 0);
+	if(name == NULL) 
+		return(-ENOMEM);
+
+	dir = (*ops->open_dir)(name, current->fsuid, current->fsgid, ed);
+	kfree(name);
+	if(IS_ERR(dir)) 
+		return(PTR_ERR(dir));
+
+	next = file->f_pos;
+	while((name = (*ops->read_dir)(dir, &next, &ino, &len, ed)) != NULL){
+		error = (*filldir)(ent, name, len, file->f_pos, ino, 
+				   DT_UNKNOWN);
+		if(error) 
+			break;
+		file->f_pos = next;
+	}
+	(*ops->close_dir)(dir, ed);
+	return(0);
+}
+
+int externfs_file_open(struct inode *ino, struct file *file)
+{
+	ino->i_nlink++;
+	return(0);
+}
+
+int externfs_fsync(struct file *file, struct dentry *dentry, int datasync)
+{
+	struct externfs_file_ops *ops = file_externfs_i(file)->ops;
+	struct inode *inode = dentry->d_inode;
+	struct externfs_data *ed = inode->i_sb->s_fs_info;
+
+	return((*ops->truncate_file)(EXTERNFS_I(inode), inode->i_size, ed));
+}
+
+static struct file_operations externfs_file_fops = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_file_read,
+	.write		= generic_file_write,
+	.mmap		= generic_file_mmap,
+	.open		= externfs_file_open,
+	.release	= NULL,
+	.fsync		= externfs_fsync,
+};
+
+static struct file_operations externfs_dir_fops = {
+	.readdir	= externfs_readdir,
+	.read		= generic_read_dir,
+};
+
+struct wp_info {
+	struct page *page;
+	int count;
+	unsigned long long start;
+	unsigned long long size;
+	int (*truncate)(struct externfs_inode *ext, __u64 size, 
+			struct externfs_data *ed);
+	struct externfs_inode *ei;
+	struct externfs_data *ed;
+};
+
+static void externfs_finish_writepage(char *buffer, int res, void *arg)
+{
+	struct wp_info *wp = arg;
+
+	if(res == wp->count){
+		ClearPageError(wp->page);
+		if(wp->start + res > wp->size)
+			(*wp->truncate)(wp->ei, wp->size, wp->ed);
+	}
+	else {
+		SetPageError(wp->page);
+		ClearPageUptodate(wp->page);
+	}		
+
+	kunmap(wp->page);
+	unlock_page(wp->page);
+	kfree(wp);
+}
+
+int externfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct externfs_file_ops *ops = EXTERNFS_I(inode)->ops;
+	struct wp_info *wp;
+	struct externfs_data *ed = inode->i_sb->s_fs_info;
+	char *buffer;
+	unsigned long long base;
+	int count = PAGE_CACHE_SIZE;
+	int end_index = inode->i_size >> PAGE_CACHE_SHIFT;
+	int err, offset;
+
+	base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT;
+
+	/* If we are entirely outside the file, then return an error */
+	err = -EIO;
+	offset = inode->i_size & (PAGE_CACHE_SIZE-1);
+	if (page->index > end_index || 
+	    ((page->index == end_index) && !offset))
+		goto out_unlock;
+
+	err = -ENOMEM;
+	wp = kmalloc(sizeof(*wp), GFP_KERNEL);
+	if(wp == NULL)
+		goto out_unlock;
+
+	*wp = ((struct wp_info) { .page		= page,
+				  .count	= count,
+				  .start	= base,
+				  .size		= inode->i_size,
+				  .truncate	= ops->truncate_file,
+				  .ei		= EXTERNFS_I(inode),
+				  .ed		= ed });
+
+	buffer = kmap(page);
+	err = (*ops->write_file)(EXTERNFS_I(inode), base, buffer, 0, 
+				 count, externfs_finish_writepage, wp, ed);
+
+	return err;
+
+ out_unlock:
+	unlock_page(page);
+	return(err);
+}
+
+static void externfs_finish_readpage(char *buffer, int res, void *arg)
+{
+	struct page *page = arg;
+	struct inode *inode;
+
+	if(res < 0){
+		SetPageError(page);
+		goto out;
+	}
+
+	inode = page->mapping->host;
+	if(inode->i_size >> PAGE_CACHE_SHIFT == page->index)
+		res = inode->i_size % PAGE_CACHE_SIZE;
+
+	memset(&buffer[res], 0, PAGE_CACHE_SIZE - res);
+
+	flush_dcache_page(page);
+	SetPageUptodate(page);
+	if (PageError(page)) 
+		ClearPageError(page);
+ out:
+	kunmap(page);
+	unlock_page(page);
+}
+
+static int externfs_readpage(struct file *file, struct page *page)
+{
+	struct inode *ino = page->mapping->host;
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *buffer;
+	long long start;
+	int err = 0;
+
+	start = (long long) page->index << PAGE_CACHE_SHIFT;
+	buffer = kmap(page);
+
+	if(ops->map_file_page != NULL){
+		/* XXX What happens when PAGE_SIZE != PAGE_CACHE_SIZE? */
+		err = (*ops->map_file_page)(file_externfs_i(file), start, 
+					    buffer, file->f_mode & FMODE_WRITE,
+					    ed);
+		if(!err)
+			err = PAGE_CACHE_SIZE;
+	}
+	else err = (*ops->read_file)(file_externfs_i(file), start, buffer,
+				     PAGE_CACHE_SIZE, 0, 0, 
+				     externfs_finish_readpage, page, ed);
+
+	if(err > 0)
+		err = 0;
+	return(err);
+}
+
+struct writepage_info {
+	struct semaphore sem;
+	int res;
+};
+
+static void externfs_finish_prepare(char *buffer, int res, void *arg)
+{
+	struct writepage_info *wp = arg;
+
+	wp->res = res;
+	up(&wp->sem);
+}
+
+int externfs_prepare_write(struct file *file, struct page *page, 
+			 unsigned int from, unsigned int to)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct externfs_file_ops *ops = EXTERNFS_I(inode)->ops;
+	struct externfs_data *ed = inode->i_sb->s_fs_info;
+	char *buffer;
+	long long start;
+	int err;
+	struct writepage_info wp;
+
+	if(PageUptodate(page))
+		return(0);
+
+	start = (long long) page->index << PAGE_CACHE_SHIFT;
+	buffer = kmap(page);
+
+	if(ops->map_file_page != NULL){
+		err = (*ops->map_file_page)(file_externfs_i(file), start, 
+					    buffer, file->f_mode & FMODE_WRITE,
+					    ed);
+		goto out;
+		
+	}
+
+	init_MUTEX_LOCKED(&wp.sem);
+	err = (*ops->read_file)(file_externfs_i(file), start, buffer,
+				PAGE_CACHE_SIZE, from, to, 
+				externfs_finish_prepare, &wp, ed);
+	down(&wp.sem);
+	if(err < 0) 
+		goto out;
+
+	err = wp.res;
+	if(err < 0)
+		goto out;
+
+	if(from > 0)
+		memset(buffer, 0, from);
+	if(to < PAGE_CACHE_SIZE)
+		memset(buffer + to, 0, PAGE_CACHE_SIZE - to);
+
+	SetPageUptodate(page);
+	err = 0;
+ out:
+	kunmap(page);
+	return(err);
+}
+
+static int externfs_commit_write(struct file *file, struct page *page, 
+			       unsigned from, unsigned to)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct externfs_file_ops *ops = EXTERNFS_I(inode)->ops;
+	unsigned long long size;
+	long long start;
+	int err;
+
+	start = (long long) (page->index << PAGE_CACHE_SHIFT);
+
+	if(ops->map_file_page != NULL)
+		err = to - from;
+	else {
+		size = start + to;
+		if(size > inode->i_size){
+			inode->i_size = size;
+			mark_inode_dirty(inode);
+		}
+	}
+
+	set_page_dirty(page);
+	return(to - from);
+}
+
+static int externfs_removepage(struct page *page, int gfpmask)
+{
+	physmem_remove_mapping(page_address(page));
+	return(0);
+}
+
+static struct address_space_operations externfs_aops = {
+	.writepage 	= externfs_writepage,
+	.readpage	= externfs_readpage,
+	.releasepage	= externfs_removepage,
+/* 	.set_page_dirty = __set_page_dirty_nobuffers, */
+	.prepare_write	= externfs_prepare_write,
+	.commit_write	= externfs_commit_write
+};
+
+static int init_inode(struct inode *inode, struct dentry *dentry)
+{
+	char *name = NULL;
+	int type, err = -ENOMEM, rdev;
+	struct externfs_inode *ext = EXTERNFS_I(inode);
+	struct externfs_file_ops *ops = ext->ops;
+	struct externfs_data *ed = inode->i_sb->s_fs_info;	
+
+	if(dentry){
+		name = dentry_name(dentry, 0);
+		if(name == NULL)
+			goto out;
+		type = (*ops->file_type)(name, &rdev, ed);
+	}
+	else type = OS_TYPE_DIR;
+
+	err = 0;
+	if(type == OS_TYPE_SYMLINK)
+		inode->i_op = &page_symlink_inode_operations;
+	else if(type == OS_TYPE_DIR)
+		inode->i_op = &externfs_dir_iops;
+	else inode->i_op = &externfs_iops;
+
+	if(type == OS_TYPE_DIR) inode->i_fop = &externfs_dir_fops;
+	else inode->i_fop = &externfs_file_fops;
+
+	if(type == OS_TYPE_SYMLINK) 
+		inode->i_mapping->a_ops = &externfs_link_aops;
+	else inode->i_mapping->a_ops = &externfs_aops;
+
+	switch (type) {
+	case OS_TYPE_CHARDEV:
+		init_special_inode(inode, S_IFCHR, rdev);
+		break;
+	case OS_TYPE_BLOCKDEV:
+		init_special_inode(inode, S_IFBLK, rdev);
+		break;
+	case OS_TYPE_FIFO:
+		init_special_inode(inode, S_IFIFO, 0);
+		break;
+	case OS_TYPE_SOCK:
+		init_special_inode(inode, S_IFSOCK, 0);
+		break;
+	case OS_TYPE_SYMLINK:
+		inode->i_mode = S_IFLNK | S_IRWXUGO;
+	}
+
+	err = (*ops->open_file)(ext, name, current->fsuid, current->fsgid, 
+				inode, ed);
+	if((err != -EISDIR) && (err != -ENOENT) && (err != -ENXIO))
+		goto out_put;
+
+	err = 0;
+
+ out_free:
+	kfree(name);
+ out:
+	return(err);
+
+ out_put:
+	iput(inode);
+	goto out_free;
+}
+
+int externfs_create(struct inode *dir, struct dentry *dentry, int mode, 
+		  struct nameidata *nd)
+{
+	struct externfs_inode *ext = EXTERNFS_I(dir);
+	struct externfs_file_ops *ops = ext->ops;
+	struct inode *inode;
+	struct externfs_data *ed = dir->i_sb->s_fs_info;
+	char *name;
+	int err = -ENOMEM;
+
+	inode = iget(dir->i_sb, 0);
+	if(inode == NULL) 
+		goto out;
+
+	err = init_inode(inode, dentry);
+	if(err) 
+		goto out_put;
+	
+	err = -ENOMEM;
+	name = dentry_name(dentry, 0);
+	if(name == NULL)
+		goto out_put;
+
+	err = (*ops->create_file)(ext, name, mode, current->fsuid, 
+				  current->fsuid, inode, ed);
+	if(err)
+		goto out_free;
+
+	err = read_name(inode, name);
+	if(err)
+		goto out_rm;
+
+	inode->i_nlink++;
+	d_instantiate(dentry, inode);
+	kfree(name);
+ out:
+	return(err);
+
+ out_rm:
+	(*ops->unlink_file)(name, ed);
+ out_free:
+	kfree(name);
+ out_put:
+	inode->i_nlink = 0;
+	iput(inode);
+	goto out;
+}
+ 
+struct dentry *externfs_lookup(struct inode *ino, struct dentry *dentry, 
+			       struct nameidata *nd)
+{
+	struct inode *inode;
+	char *name;
+	int err = -ENOMEM;
+
+	inode = iget(ino->i_sb, 0);
+	if(inode == NULL) 
+		goto out;
+
+	err = init_inode(inode, dentry);
+	if(err) 
+		goto out_put;
+	
+	err = -ENOMEM;
+	name = dentry_name(dentry, 0);
+	if(name == NULL)
+		goto out_put;
+
+	err = read_name(inode, name);
+	kfree(name);
+	if(err){
+		if(err != -ENOENT)
+			goto out_put;
+
+		inode->i_nlink = 0;
+		iput(inode);
+		inode = NULL;
+	}
+	d_add(dentry, inode);
+	dentry->d_op = &externfs_dentry_ops;
+	return(NULL);
+
+ out_put:
+	inode->i_nlink = 0;
+	iput(inode);
+ out:
+	return(ERR_PTR(err));
+}
+
+static char *inode_dentry_name(struct inode *ino, struct dentry *dentry)
+{
+        char *file;
+	int len;
+
+	file = inode_name(ino, dentry->d_name.len + 1);
+	if(file == NULL) return(NULL);
+        strcat(file, "/");
+	len = strlen(file);
+        strncat(file, dentry->d_name.name, dentry->d_name.len);
+	file[len + dentry->d_name.len] = '\0';
+        return(file);
+}
+
+int externfs_link(struct dentry *to, struct inode *ino, struct dentry *from)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+        char *from_name, *to_name;
+        int err = -ENOMEM;
+
+        from_name = inode_dentry_name(ino, from); 
+        if(from_name == NULL) 
+		goto out;
+
+        to_name = dentry_name(to, 0);
+	if(to_name == NULL)
+		goto out_free_from;
+
+        err = (*ops->link_file)(to_name, from_name, current->fsuid, 
+				current->fsgid, ed);
+	if(err)
+		goto out_free_to;
+
+	d_instantiate(from, to->d_inode);
+	to->d_inode->i_nlink++;
+	atomic_inc(&to->d_inode->i_count);
+
+ out_free_to:
+        kfree(to_name);
+ out_free_from:
+        kfree(from_name);
+ out:
+        return(err);
+}
+
+int externfs_unlink(struct inode *ino, struct dentry *dentry)
+{
+	struct inode *inode;
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *file;
+	int err;
+
+	file = inode_dentry_name(ino, dentry);
+	if(file == NULL) 
+		return(-ENOMEM);
+
+	inode = dentry->d_inode;
+	if((inode->i_nlink == 1) && (ops->invisible != NULL))
+		(*ops->invisible)(EXTERNFS_I(inode));
+
+	err = (*ops->unlink_file)(file, ed);
+	kfree(file);
+
+	inode->i_nlink--;
+
+	return(err);
+}
+
+int externfs_symlink(struct inode *ino, struct dentry *dentry, const char *to)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct inode *inode;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *file;
+	int err;
+
+	file = inode_dentry_name(ino, dentry);
+	if(file == NULL) 
+		return(-ENOMEM);
+	err = (*ops->make_symlink)(file, to, current->fsuid, current->fsgid,
+				   ed);
+	kfree(file);
+	if(err) 
+		goto out;
+
+	err = -ENOMEM;
+	inode = iget(ino->i_sb, 0);
+	if(inode == NULL) 
+		goto out;
+
+	err = init_inode(inode, dentry);
+	if(err) 
+		goto out_put;
+	
+	d_instantiate(dentry, inode);
+	inode->i_nlink++;
+ out:
+	return(err);
+
+ out_put:
+	iput(inode);
+	goto out;
+}
+
+int externfs_make_dir(struct inode *ino, struct dentry *dentry, int mode)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct inode *inode;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *file;
+	int err = -ENOMEM;
+
+	file = inode_dentry_name(ino, dentry);
+	if(file == NULL) 
+		goto out;
+	err = (*ops->make_dir)(file, mode, current->fsuid, current->fsgid, ed);
+
+	err = -ENOMEM;
+	inode = iget(ino->i_sb, 0);
+	if(inode == NULL) 
+		goto out_free;
+
+	err = init_inode(inode, dentry);
+	if(err) 
+		goto out_put;
+	
+	err = read_name(inode, file);
+	if(err)
+		goto out_put;
+
+	kfree(file);
+	d_instantiate(dentry, inode);
+	inode->i_nlink = 2;
+	inode->i_mode = S_IFDIR | mode;
+
+	ino->i_nlink++;
+ out:
+	return(err);
+ out_put:
+	inode->i_nlink = 0;
+	iput(inode);
+ out_free:
+	kfree(file);
+	goto out;	
+}
+
+int externfs_remove_dir(struct inode *ino, struct dentry *dentry)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *file;
+	int err;
+
+	file = inode_dentry_name(ino, dentry);
+	if(file == NULL) 
+		return(-ENOMEM);
+	err = (*ops->remove_dir)(file, current->fsuid, current->fsgid, ed);
+	kfree(file);
+
+	dentry->d_inode->i_nlink = 0;
+	ino->i_nlink--;
+	return(err);
+}
+
+int externfs_make_node(struct inode *dir, struct dentry *dentry, int mode, 
+		     dev_t dev)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(dir)->ops;
+	struct externfs_data *ed = dir->i_sb->s_fs_info;
+	struct inode *inode;
+	char *name;
+	int err = -ENOMEM;
+ 
+	inode = iget(dir->i_sb, 0);
+	if(inode == NULL) 
+		goto out;
+
+	err = init_inode(inode, dentry);
+	if(err) 
+		goto out_put;
+
+	err = -ENOMEM;
+	name = dentry_name(dentry, 0);
+	if(name == NULL)
+		goto out_put;
+
+	init_special_inode(inode, mode, dev);
+	err = (*ops->make_node)(name, mode & S_IRWXUGO, current->fsuid, 
+				current->fsgid, mode & S_IFMT, MAJOR(dev), 
+				MINOR(dev), ed);
+	if(err)
+		goto out_free;
+	
+	err = read_name(inode, name);
+	if(err)
+		goto out_rm;
+
+	inode->i_nlink++;
+	d_instantiate(dentry, inode);
+	kfree(name);
+ out:
+	return(err);
+
+ out_rm:
+	(*ops->unlink_file)(name, ed);
+ out_free:
+	kfree(name);
+ out_put:
+	inode->i_nlink = 0;
+	iput(inode);
+	goto out;
+}
+
+int externfs_rename(struct inode *from_ino, struct dentry *from,
+		  struct inode *to_ino, struct dentry *to)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(from_ino)->ops;
+	struct externfs_data *ed = from_ino->i_sb->s_fs_info;
+	char *from_name, *to_name;
+	int err;
+
+	from_name = inode_dentry_name(from_ino, from);
+	if(from_name == NULL)
+		return(-ENOMEM);
+	to_name = inode_dentry_name(to_ino, to);
+	if(to_name == NULL){
+		kfree(from_name);
+		return(-ENOMEM);
+	}
+	err = (*ops->rename_file)(from_name, to_name, ed);
+	kfree(from_name);
+	kfree(to_name);
+
+	from_ino->i_nlink--;
+	to_ino->i_nlink++;
+	return(err);
+}
+
+void externfs_truncate(struct inode *ino)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+
+	(*ops->truncate_file)(EXTERNFS_I(ino), ino->i_size, ed);
+}
+
+int externfs_permission(struct inode *ino, int desired, struct nameidata *nd)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *name;
+	int r = 0, w = 0, x = 0, err;
+
+	if(ops->access_file == NULL)
+		return(vfs_permission(ino, desired));
+
+	if(desired & MAY_READ) r = 1;
+	if(desired & MAY_WRITE) w = 1;
+	if(desired & MAY_EXEC) x = 1;
+	name = inode_name(ino, 0);
+	if(name == NULL) 
+		return(-ENOMEM);
+
+	err = (*ops->access_file)(name, r, w, x, current->fsuid,
+				  current->fsgid, ed);
+	kfree(name);
+
+	if(!err) 
+		err = vfs_permission(ino, desired);
+	return(err);
+}
+
+int externfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct externfs_file_ops *ops = EXTERNFS_I(dentry->d_inode)->ops;
+	struct externfs_data *ed = dentry->d_inode->i_sb->s_fs_info;
+	struct externfs_iattr attrs;
+	char *name;
+	int err;
+	
+	attrs.ia_valid = 0;
+	if(attr->ia_valid & ATTR_MODE){
+		attrs.ia_valid |= EXTERNFS_ATTR_MODE;
+		attrs.ia_mode = attr->ia_mode;
+	}
+	if(attr->ia_valid & ATTR_UID){
+		attrs.ia_valid |= EXTERNFS_ATTR_UID;
+		attrs.ia_uid = attr->ia_uid;
+	}
+	if(attr->ia_valid & ATTR_GID){
+		attrs.ia_valid |= EXTERNFS_ATTR_GID;
+		attrs.ia_gid = attr->ia_gid;
+	}
+	if(attr->ia_valid & ATTR_SIZE){
+		attrs.ia_valid |= EXTERNFS_ATTR_SIZE;
+		attrs.ia_size = attr->ia_size;
+	}
+	if(attr->ia_valid & ATTR_ATIME){
+		attrs.ia_valid |= EXTERNFS_ATTR_ATIME;
+		attrs.ia_atime = attr->ia_atime.tv_sec;
+	}
+	if(attr->ia_valid & ATTR_MTIME){
+		attrs.ia_valid |= EXTERNFS_ATTR_MTIME;
+		attrs.ia_mtime = attr->ia_mtime.tv_sec;
+	}
+	if(attr->ia_valid & ATTR_CTIME){
+		attrs.ia_valid |= EXTERNFS_ATTR_CTIME;
+		attrs.ia_ctime = attr->ia_ctime.tv_sec;
+	}
+	if(attr->ia_valid & ATTR_ATIME_SET){
+		attrs.ia_valid |= EXTERNFS_ATTR_ATIME_SET;
+		attrs.ia_atime = attr->ia_atime.tv_sec;
+	}
+	if(attr->ia_valid & ATTR_MTIME_SET){
+		attrs.ia_valid |= EXTERNFS_ATTR_MTIME_SET;
+	}
+	name = dentry_name(dentry, 0);
+	if(name == NULL) 
+		return(-ENOMEM);
+	err = (*ops->set_attr)(name, &attrs, ed);
+	kfree(name);
+	if(err)
+		return(err);
+
+	return(inode_setattr(dentry->d_inode, attr));
+}
+
+int externfs_getattr(struct vfsmount *mnt, struct dentry *dentry, 
+		     struct kstat *stat)
+{
+	generic_fillattr(dentry->d_inode, stat);
+	return(0);
+}
+
+static struct inode_operations externfs_iops = {
+	.create		= externfs_create,
+	.link		= externfs_link,
+	.unlink		= externfs_unlink,
+	.symlink	= externfs_symlink,
+	.mkdir		= externfs_make_dir,
+	.rmdir		= externfs_remove_dir,
+	.mknod		= externfs_make_node,
+	.rename		= externfs_rename,
+	.truncate	= externfs_truncate,
+	.permission	= externfs_permission,
+	.setattr	= externfs_setattr,
+	.getattr	= externfs_getattr,
+};
+
+static struct inode_operations externfs_dir_iops = {
+	.create		= externfs_create,
+	.lookup		= externfs_lookup,
+	.link		= externfs_link,
+	.unlink		= externfs_unlink,
+	.symlink	= externfs_symlink,
+	.mkdir		= externfs_make_dir,
+	.rmdir		= externfs_remove_dir,
+	.mknod		= externfs_make_node,
+	.rename		= externfs_rename,
+	.truncate	= externfs_truncate,
+	.permission	= externfs_permission,
+	.setattr	= externfs_setattr,
+	.getattr	= externfs_getattr,
+};
+
+int externfs_link_readpage(struct file *file, struct page *page)
+{
+	struct inode *ino = page->mapping->host;
+	struct externfs_file_ops *ops = EXTERNFS_I(ino)->ops;
+	struct externfs_data *ed = ino->i_sb->s_fs_info;
+	char *buffer, *name;
+	long long start;
+	int err;
+
+	start = page->index << PAGE_CACHE_SHIFT;
+	buffer = kmap(page);
+	name = inode_name(ino, 0);
+	if(name == NULL) 
+		return(-ENOMEM);
+
+	err = (*ops->read_link)(name, current->fsuid, current->fsgid, buffer, 
+				PAGE_CACHE_SIZE, ed);
+
+	kfree(name);
+	if(err == PAGE_CACHE_SIZE)
+		err = -E2BIG;
+	else if(err > 0){
+		flush_dcache_page(page);
+		SetPageUptodate(page);
+		if (PageError(page)) ClearPageError(page);
+		err = 0;
+	}
+	kunmap(page);
+	unlock_page(page);
+	return(err);
+}
+
+static int externfs_flushpage(struct page *page, unsigned long offset)
+{
+	return(externfs_writepage(page, NULL));
+}
+
+struct externfs_data *inode_externfs_info(struct inode *inode)
+{
+	return(inode->i_sb->s_fs_info);
+}
+
+static struct address_space_operations externfs_link_aops = {
+	.readpage	= externfs_link_readpage,
+	.releasepage	= externfs_removepage,
+	.invalidatepage	= externfs_flushpage,
+};
+
+DECLARE_MUTEX(externfs_sem);
+struct list_head externfses = LIST_HEAD_INIT(externfses);
+
+static struct externfs *find_externfs(struct file_system_type *type)
+{
+	struct list_head *ele;
+	struct externfs *fs;
+
+	down(&externfs_sem);
+	list_for_each(ele, &externfses){
+		fs = list_entry(ele, struct externfs, list);
+		if(&fs->type == type)
+			goto out;
+	}
+	fs = NULL;
+ out:
+	up(&externfs_sem);
+	return(fs);
+}
+
+#define DEFAULT_ROOT "/"
+
+char *host_root_filename(char *mount_arg)
+{
+	char *root = DEFAULT_ROOT;
+
+	if((mount_arg != NULL) && (*mount_arg != '\0'))
+		root = mount_arg;
+
+	return(uml_strdup(root));
+}
+
+static int externfs_fill_sb(struct super_block *sb, void *data, int silent)
+{
+	struct externfs *fs;
+	struct inode *root_inode;
+	struct externfs_data *sb_data;
+	int err = -EINVAL;
+
+	sb->s_blocksize = 1024;
+	sb->s_blocksize_bits = 10;
+	sb->s_magic = EXTERNFS_SUPER_MAGIC;
+	sb->s_op = &externfs_sbops;
+
+	fs = find_externfs(sb->s_type);
+	if(fs == NULL){
+		printk("Couldn't find externfs for filesystem '%s'\n",
+		       sb->s_type->name);
+		goto out;
+	}
+
+	sb_data = (*fs->mount_ops->mount)(data);
+	if(IS_ERR(sb_data)){
+		err = PTR_ERR(sb_data);
+		goto out;
+	}
+		
+	sb->s_fs_info = sb_data;
+	sb_data->mount_ops = fs->mount_ops;
+
+	root_inode = iget(sb, 0);
+	if(root_inode == NULL)
+		goto out;
+
+	err = init_inode(root_inode, NULL);
+	if(err)
+		goto out_put;
+
+	err = -ENOMEM;
+	sb->s_root = d_alloc_root(root_inode);
+	if(sb->s_root == NULL)
+		goto out_put;
+
+	err = read_inode(root_inode);
+	if(err)
+		goto out_put;
+
+ out:
+	return(err);
+
+ out_put:
+	iput(root_inode);
+	goto out;
+}	
+
+struct super_block *externfs_read_super(struct file_system_type *type, 
+					int flags, const char *dev_name, 
+					void *data)
+{
+	return(get_sb_nodev(type, flags, data, externfs_fill_sb));
+}
+
+void init_externfs(struct externfs_data *ed, struct externfs_file_ops *ops)
+{
+	ed->file_ops = ops;
+}
+
+int register_externfs(char *name, struct externfs_mount_ops *mount_ops)
+{
+	struct externfs *new;
+	int err = -ENOMEM;
+
+	new = kmalloc(sizeof(*new), GFP_KERNEL);
+	if(new == NULL)
+		goto out;
+
+	memset(new, 0, sizeof(*new));
+	*new = ((struct externfs) { .list	= LIST_HEAD_INIT(new->list),
+				    .mount_ops	= mount_ops,
+				    .type = { .name	= name,
+					      .get_sb	= externfs_read_super,
+					      .kill_sb	= kill_anon_super,
+					      .fs_flags	= 0,
+					      .owner	= THIS_MODULE } });
+	list_add(&new->list, &externfses);
+
+	err = register_filesystem(&new->type);
+	if(err)
+		goto out_del;
+	return(0);
+
+ out_del:
+	list_del(&new->list);
+	kfree(new);
+ out:
+	return(err);
+}
+
+void unregister_externfs(char *name)
+{
+	struct list_head *ele;
+	struct externfs *fs;
+
+	down(&externfs_sem);
+	list_for_each(ele, &externfses){
+		fs = list_entry(ele, struct externfs, list);
+		if(!strcmp(fs->type.name, name)){
+			list_del(ele);
+			up(&externfs_sem);
+			return;
+		}
+	}
+	up(&externfs_sem);
+	printk("Unregister_externfs - filesystem '%s' not found\n", name);
+}
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */
Index: um/fs/hostfs/hostfs.h
===================================================================
--- um.orig/fs/hostfs/hostfs.h	2004-08-06 15:17:22.000000000 -0400
+++ um/fs/hostfs/hostfs.h	2004-08-07 12:07:06.000000000 -0400
@@ -1,69 +1,178 @@
+/* 
+ * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL
+ */
+
 #ifndef __UM_FS_HOSTFS
 #define __UM_FS_HOSTFS
 
+#include "linux/fs.h"
+#include "filehandle.h"
 #include "os.h"
 
 /* These are exactly the same definitions as in fs.h, but the names are 
  * changed so that this file can be included in both kernel and user files.
  */
 
-#define HOSTFS_ATTR_MODE	1
-#define HOSTFS_ATTR_UID 	2
-#define HOSTFS_ATTR_GID 	4
-#define HOSTFS_ATTR_SIZE	8
-#define HOSTFS_ATTR_ATIME	16
-#define HOSTFS_ATTR_MTIME	32
-#define HOSTFS_ATTR_CTIME	64
-#define HOSTFS_ATTR_ATIME_SET	128
-#define HOSTFS_ATTR_MTIME_SET	256
-#define HOSTFS_ATTR_FORCE	512	/* Not a change, but a change it */
-#define HOSTFS_ATTR_ATTR_FLAG	1024
+#define EXTERNFS_ATTR_MODE	1
+#define EXTERNFS_ATTR_UID 	2
+#define EXTERNFS_ATTR_GID 	4
+#define EXTERNFS_ATTR_SIZE	8
+#define EXTERNFS_ATTR_ATIME	16
+#define EXTERNFS_ATTR_MTIME	32
+#define EXTERNFS_ATTR_CTIME	64
+#define EXTERNFS_ATTR_ATIME_SET	128
+#define EXTERNFS_ATTR_MTIME_SET	256
+#define EXTERNFS_ATTR_FORCE	512	/* Not a change, but a change it */
+#define EXTERNFS_ATTR_ATTR_FLAG	1024
 
-struct hostfs_iattr {
+struct externfs_iattr {
 	unsigned int	ia_valid;
 	mode_t		ia_mode;
 	uid_t		ia_uid;
 	gid_t		ia_gid;
 	loff_t		ia_size;
-	struct timespec	ia_atime;
-	struct timespec	ia_mtime;
-	struct timespec	ia_ctime;
+	time_t		ia_atime;
+	time_t		ia_mtime;
+	time_t		ia_ctime;
 	unsigned int	ia_attr_flags;
 };
 
-extern int stat_file(const char *path, unsigned long long *inode_out, 
-		     int *mode_out, int *nlink_out, int *uid_out, int *gid_out,
-		     unsigned long long *size_out, struct timespec *atime_out, 
-		     struct timespec *mtime_out, struct timespec *ctime_out, 
-		     int *blksize_out, unsigned long long *blocks_out);
-extern int access_file(char *path, int r, int w, int x);
-extern int hostfs_open_file(char *path, int r, int w, int append);
-extern int file_type(const char *path, int *rdev);
-extern void *hostfs_open_dir(char *path, int *err_out);
-extern char *read_dir(void *stream, unsigned long long *pos, 
-		      unsigned long long *ino_out, int *len_out);
-extern void hostfs_close_file(void *stream);
-extern void close_dir(void *stream);
-extern int hostfs_read_file(int fd, unsigned long long *offset, char *buf, int len);
-extern int hostfs_write_file(int fd, unsigned long long *offset, const char *buf,
-		      int len);
-extern int lseek_file(int fd, long long offset, int whence);
-extern int file_create(char *name, int ur, int uw, int ux, int gr, 
-		       int gw, int gx, int or, int ow, int ox);
-extern int set_attr(const char *file, struct hostfs_iattr *attrs);
-extern int make_symlink(const char *from, const char *to);
-extern int unlink_file(const char *file);
-extern int do_mkdir(const char *file, int mode);
-extern int do_rmdir(const char *file);
-extern int do_mknod(const char *file, int mode, int dev);
-extern int link_file(const char *from, const char *to);
-extern int do_readlink(char *file, char *buf, int size);
-extern int rename_file(char *from, char *to);
-extern int do_statfs(char *root, long *bsize_out, long long *blocks_out, 
-		     long long *bfree_out, long long *bavail_out, 
-		     long long *files_out, long long *ffree_out, 
-		     void *fsid_out, int fsid_size, long *namelen_out, 
-		     long *spare_out);
+struct externfs_data {
+	struct externfs_file_ops *file_ops;
+	struct externfs_mount_ops *mount_ops;
+};
+
+struct externfs_inode {
+	struct inode vfs_inode;
+	struct externfs_file_ops *ops;
+};
+
+struct externfs_mount_ops {
+	struct externfs_data *(*mount)(char *mount_arg);
+	struct externfs_inode *(*init_file)(struct externfs_data *ed);
+};
+
+struct externfs_file_ops {
+	int (*stat_file)(const char *path, struct externfs_data *ed, 
+			 dev_t *dev_out, unsigned long long *inode_out, 
+			 int *mode_out, int *nlink_out, int *uid_out, 
+			 int *gid_out, unsigned long long *size_out, 
+			 unsigned long *atime_out, unsigned long *mtime_out,
+			 unsigned long *ctime_out, int *blksize_out, 
+			 unsigned long long *blocks_out);
+	int (*file_type)(const char *path, int *rdev, 
+			 struct externfs_data *ed);
+	int (*access_file)(char *path, int r, int w, int x, int uid, int gid, 
+			   struct externfs_data *ed);
+	int (*open_file)(struct externfs_inode *ext, char *file, 
+			 int uid, int gid, struct inode *inode, 
+			 struct externfs_data *ed);
+	void (*close_file)(struct externfs_inode *ext, 
+			   unsigned long long size);
+	void *(*open_dir)(char *path, int uid, int gid, 
+			  struct externfs_data *ed);
+	char *(*read_dir)(void *stream, unsigned long long *pos, 
+			  unsigned long long *ino_out, int *len_out, 
+			  struct externfs_data *ed);
+	int (*read_file)(struct externfs_inode *ext, 
+			 unsigned long long offset, char *buf, int len, 
+			 int ignore_start, int ignore_end,
+			 void (*completion)(char *, int, void *), void *arg, 
+			 struct externfs_data *ed);
+	int (*write_file)(struct externfs_inode *ext, 
+			  unsigned long long offset, const char *buf, 
+			  int start, int len, 
+			  void (*completion)(char *, int, void *), void *arg, 
+			  struct externfs_data *ed);
+	int (*map_file_page)(struct externfs_inode *ext, 
+			     unsigned long long offset, char *buf, int w, 
+			     struct externfs_data *ed);
+	void (*close_dir)(void *stream, struct externfs_data *ed);
+	void (*invisible)(struct externfs_inode *ext);
+	int (*create_file)(struct externfs_inode *ext, char *path, 
+			   int mode, int uid, int gid, struct inode *inode, 
+			   struct externfs_data *ed);
+	int (*set_attr)(const char *path, struct externfs_iattr *attrs, 
+			struct externfs_data *ed);
+	int (*make_symlink)(const char *from, const char *to, int uid, int gid,
+			    struct externfs_data *ed);
+	int (*unlink_file)(const char *path, struct externfs_data *ed);
+	int (*make_dir)(const char *path, int mode, int uid, int gid, 
+			struct externfs_data *ed);
+	int (*remove_dir)(const char *path, int uid, int gid, 
+			  struct externfs_data *ed);
+	int (*make_node)(const char *path, int mode, int uid, int gid, 
+			 int type, int maj, int min, struct externfs_data *ed);
+	int (*link_file)(const char *to, const char *from, int uid, int gid, 
+			 struct externfs_data *ed);
+	int (*read_link)(char *path, int uid, int gid, char *buf, int size, 
+			 struct externfs_data *ed);
+	int (*rename_file)(char *from, char *to, struct externfs_data *ed);
+	int (*statfs)(long *bsize_out, long long *blocks_out, 
+		      long long *bfree_out, long long *bavail_out, 
+		      long long *files_out, long long *ffree_out,
+		      void *fsid_out, int fsid_size, long *namelen_out, 
+		      long *spare_out, struct externfs_data *ed);
+	int (*truncate_file)(struct externfs_inode *ext, __u64 size, 
+			     struct externfs_data *ed);
+};
+
+#define HOSTFS_BUFSIZE 64
+
+extern int register_externfs(char *name, struct externfs_mount_ops *mount_ops);
+extern void unregister_externfs(char *name);
+extern void init_externfs(struct externfs_data *ed, 
+			  struct externfs_file_ops *ops);
+struct externfs_data *inode_externfs_info(struct inode *inode);
+
+extern char *generic_root_filename(char *mount_arg);
+extern void host_close_file(void *stream);
+extern int host_read_file(int fd, unsigned long long offset, char *buf, 
+			  int len);
+extern int host_open_file(const char *path[], int r, int w,
+			  struct file_handle *fh);
+extern void *host_open_dir(const char *path[]);
+extern char *host_read_dir(void *stream, unsigned long long *pos, 
+			   unsigned long long *ino_out, int *len_out);
+extern int host_file_type(const char *path[], int *rdev);
+extern char *host_root_filename(char *mount_arg);
+extern char *get_path(const char *path[], char *buf, int size);
+extern void free_path(const char *buf, char *tmp);
+extern int host_create_file(const char *path[], int mode, 
+			    struct file_handle *fh);
+extern int host_set_attr(const char *path[], struct externfs_iattr *attrs);
+extern int host_make_symlink(const char *from[], const char *to);
+extern int host_unlink_file(const char *path[]);
+extern int host_make_dir(const char *path[], int mode);
+extern int host_remove_dir(const char *path[]);
+extern int host_link_file(const char *to[], const char *from[]);
+extern int host_read_link(const char *path[], char *buf, int size);
+extern int host_rename_file(const char *from[], const char *to[]);
+extern int host_stat_fs(const char *path[], long *bsize_out, 
+			long long *blocks_out, long long *bfree_out, 
+			long long *bavail_out, long long *files_out, 
+			long long *ffree_out, void *fsid_out, int fsid_size, 
+			long *namelen_out, long *spare_out);
+extern int host_stat_file(const char *path[], int *dev_out, 
+			  unsigned long long *inode_out, int *mode_out, 
+			  int *nlink_out, int *uid_out, int *gid_out, 
+			  unsigned long long *size_out, 
+			  unsigned long *atime_out, unsigned long *mtime_out,
+			  unsigned long *ctime_out, int *blksize_out,
+			  unsigned long long *blocks_out);
+
+extern char *generic_host_read_dir(void *stream, unsigned long long *pos, 
+			      unsigned long long *ino_out, int *len_out, 
+			      void *mount);
+extern int generic_host_read_file(int fd, unsigned long long offset, char *buf,
+			     int len, void *mount);
+extern void generic_host_close_file(void *stream, unsigned long long size,
+				    void *mount);
+extern int generic_host_truncate_file(struct file_handle *fh, __u64 size, 
+				      void *m);
+
+extern char *inode_name_prefix(struct inode *inode, char *prefix);
 
 #endif