Linux-2.6.12-rc2v2.6.12-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!

1 files changed, 1045 insertions, 0 deletions

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
new file mode 100644
index 000000000000..a88ad2924851
--- /dev/null
+++ b/fs/hostfs/hostfs_kern.c
@@ -0,0 +1,1045 @@
+/*
+ * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ *
+ * Ported the filesystem routines to 2.5.
+ * 2003-02-10 Petr Baudis <pasky@ucw.cz>
+ */
+
+#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/list.h>
+#include <linux/root_dev.h>
+#include <linux/statfs.h>
+#include <linux/kdev_t.h>
+#include <asm/uaccess.h>
+#include "hostfs.h"
+#include "kern_util.h"
+#include "kern.h"
+#include "user_util.h"
+#include "2_5compat.h"
+#include "init.h"
+
+struct hostfs_inode_info {
+        char *host_filename;
+        int fd;
+        int mode;
+        struct inode vfs_inode;
+};
+
+static inline struct hostfs_inode_info *HOSTFS_I(struct inode *inode)
+{
+        return(list_entry(inode, struct hostfs_inode_info, vfs_inode));
+}
+
+#define FILE_HOSTFS_I(file) HOSTFS_I((file)->f_dentry->d_inode)
+
+int hostfs_d_delete(struct dentry *dentry)
+{
+        return(1);
+}
+
+struct dentry_operations hostfs_dentry_ops = {
+        .d_delete               = hostfs_d_delete,
+};
+
+/* Changed in hostfs_args before the kernel starts running */
+static char *root_ino = "/";
+static int append = 0;
+
+#define HOSTFS_SUPER_MAGIC 0x00c0ffee
+
+static struct inode_operations hostfs_iops;
+static struct inode_operations hostfs_dir_iops;
+static struct address_space_operations hostfs_link_aops;
+
+#ifndef MODULE
+static int __init hostfs_args(char *options, int *add)
+{
+        char *ptr;
+
+        ptr = strchr(options, ',');
+        if(ptr != NULL)
+                *ptr++ = '\0';
+        if(*options != '\0')
+                root_ino = options;
+
+        options = ptr;
+        while(options){
+                ptr = strchr(options, ',');
+                if(ptr != NULL)
+                        *ptr++ = '\0';
+                if(*options != '\0'){
+                        if(!strcmp(options, "append"))
+                                append = 1;
+                        else printf("hostfs_args - unsupported option - %s\n",
+                                    options);
+                }
+                options = ptr;
+        }
+        return(0);
+}
+
+__uml_setup("hostfs=", hostfs_args,
+"hostfs=<root dir>,<flags>,...\n"
+"    This is used to set hostfs parameters.  The root directory argument\n"
+"    is used to confine all hostfs mounts to within the specified directory\n"
+"    tree on the host.  If this isn't specified, then a user inside UML can\n"
+"    mount anything on the host that's accessible to the user that's running\n"
+"    it.\n"
+"    The only flag currently supported is 'append', which specifies that all\n"
+"    files opened by hostfs will be opened in append mode.\n\n"
+);
+#endif
+
+static char *dentry_name(struct dentry *dentry, int extra)
+{
+        struct dentry *parent;
+        char *root, *name;
+        int len;
+
+        len = 0;
+        parent = dentry;
+        while(parent->d_parent != parent){
+                len += parent->d_name.len + 1;
+                parent = parent->d_parent;
+        }
+
+        root = HOSTFS_I(parent->d_inode)->host_filename;
+        len += strlen(root);
+        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;
+        }
+        strncpy(name, root, strlen(root));
+        return(name);
+}
+
+static 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));
+}
+
+static int read_name(struct inode *ino, char *name)
+{
+        /* 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
+         */
+        int err;
+        int i_mode, i_nlink, i_blksize;
+        unsigned long long i_size;
+        unsigned long long i_ino;
+        unsigned long long i_blocks;
+
+        err = stat_file(name, &i_ino, &i_mode, &i_nlink, &ino->i_uid,
+                        &ino->i_gid, &i_size, &ino->i_atime, &ino->i_mtime,
+                        &ino->i_ctime, &i_blksize, &i_blocks);
+        if(err)
+                return(err);
+
+        ino->i_ino = i_ino;
+        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;
+        if((ino->i_sb->s_dev == ROOT_DEV) && (ino->i_uid == getuid()))
+                ino->i_uid = 0;
+        return(0);
+}
+
+static char *follow_link(char *link)
+{
+        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_readlink(link, name, len);
+                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);
+        kfree(link);
+        return(resolved);
+
+ out_free:
+        kfree(name);
+ out:
+        return(ERR_PTR(n));
+}
+
+static int read_inode(struct inode *ino)
+{
+        char *name;
+        int err = 0;
+
+        /* 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;
+
+        if(file_type(name, NULL, NULL) == OS_TYPE_SYMLINK){
+                name = follow_link(name);
+                if(IS_ERR(name)){
+                        err = PTR_ERR(name);
+                        goto out;
+                }
+        }
+
+        err = read_name(ino, name);
+        kfree(name);
+ out:
+        return(err);
+}
+
+int hostfs_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;
+
+        err = do_statfs(HOSTFS_I(sb->s_root->d_inode)->host_filename,
+                        &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);
+        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 = HOSTFS_SUPER_MAGIC;
+        return(0);
+}
+
+static struct inode *hostfs_alloc_inode(struct super_block *sb)
+{
+        struct hostfs_inode_info *hi;
+
+        hi = kmalloc(sizeof(*hi), GFP_KERNEL);
+        if(hi == NULL)
+                return(NULL);
+
+        *hi = ((struct hostfs_inode_info) { .host_filename      = NULL,
+                                            .fd                 = -1,
+                                            .mode               = 0 });
+        inode_init_once(&hi->vfs_inode);
+        return(&hi->vfs_inode);
+}
+
+static void hostfs_delete_inode(struct inode *inode)
+{
+        if(HOSTFS_I(inode)->fd != -1) {
+                close_file(&HOSTFS_I(inode)->fd);
+                HOSTFS_I(inode)->fd = -1;
+        }
+        clear_inode(inode);
+}
+
+static void hostfs_destroy_inode(struct inode *inode)
+{
+        if(HOSTFS_I(inode)->host_filename)
+                kfree(HOSTFS_I(inode)->host_filename);
+
+        /*XXX: This should not happen, probably. The check is here for
+         * additional safety.*/
+        if(HOSTFS_I(inode)->fd != -1) {
+                close_file(&HOSTFS_I(inode)->fd);
+                printk(KERN_DEBUG "Closing host fd in .destroy_inode\n");
+        }
+
+        kfree(HOSTFS_I(inode));
+}
+
+static void hostfs_read_inode(struct inode *inode)
+{
+        read_inode(inode);
+}
+
+static struct super_operations hostfs_sbops = {
+        .alloc_inode    = hostfs_alloc_inode,
+        .drop_inode     = generic_delete_inode,
+        .delete_inode   = hostfs_delete_inode,
+        .destroy_inode  = hostfs_destroy_inode,
+        .read_inode     = hostfs_read_inode,
+        .statfs         = hostfs_statfs,
+};
+
+int hostfs_readdir(struct file *file, void *ent, filldir_t filldir)
+{
+        void *dir;
+        char *name;
+        unsigned long long next, ino;
+        int error, len;
+
+        name = dentry_name(file->f_dentry, 0);
+        if(name == NULL) return(-ENOMEM);
+        dir = open_dir(name, &error);
+        kfree(name);
+        if(dir == NULL) return(-error);
+        next = file->f_pos;
+        while((name = read_dir(dir, &next, &ino, &len)) != NULL){
+                error = (*filldir)(ent, name, len, file->f_pos,
+                                   ino, DT_UNKNOWN);
+                if(error) break;
+                file->f_pos = next;
+        }
+        close_dir(dir);
+        return(0);
+}
+
+int hostfs_file_open(struct inode *ino, struct file *file)
+{
+        char *name;
+        int mode = 0, r = 0, w = 0, fd;
+
+        mode = file->f_mode & (FMODE_READ | FMODE_WRITE);
+        if((mode & HOSTFS_I(ino)->mode) == mode)
+                return(0);
+
+        /* The file may already have been opened, but with the wrong access,
+         * so this resets things and reopens the file with the new access.
+         */
+        if(HOSTFS_I(ino)->fd != -1){
+                close_file(&HOSTFS_I(ino)->fd);
+                HOSTFS_I(ino)->fd = -1;
+        }
+
+        HOSTFS_I(ino)->mode |= mode;
+        if(HOSTFS_I(ino)->mode & FMODE_READ)
+                r = 1;
+        if(HOSTFS_I(ino)->mode & FMODE_WRITE)
+                w = 1;
+        if(w)
+                r = 1;
+
+        name = dentry_name(file->f_dentry, 0);
+        if(name == NULL)
+                return(-ENOMEM);
+
+        fd = open_file(name, r, w, append);
+        kfree(name);
+        if(fd < 0) return(fd);
+        FILE_HOSTFS_I(file)->fd = fd;
+
+        return(0);
+}
+
+int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync)
+{
+        return(0);
+}
+
+static struct file_operations hostfs_file_fops = {
+        .llseek         = generic_file_llseek,
+        .read           = generic_file_read,
+        .sendfile       = generic_file_sendfile,
+        .aio_read       = generic_file_aio_read,
+        .aio_write      = generic_file_aio_write,
+        .readv          = generic_file_readv,
+        .writev         = generic_file_writev,
+        .write          = generic_file_write,
+        .mmap           = generic_file_mmap,
+        .open           = hostfs_file_open,
+        .release        = NULL,
+        .fsync          = hostfs_fsync,
+};
+
+static struct file_operations hostfs_dir_fops = {
+        .llseek         = generic_file_llseek,
+        .readdir        = hostfs_readdir,
+        .read           = generic_read_dir,
+};
+
+int hostfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+        struct address_space *mapping = page->mapping;
+        struct inode *inode = mapping->host;
+        char *buffer;
+        unsigned long long base;
+        int count = PAGE_CACHE_SIZE;
+        int end_index = inode->i_size >> PAGE_CACHE_SHIFT;
+        int err;
+
+        if (page->index >= end_index)
+                count = inode->i_size & (PAGE_CACHE_SIZE-1);
+
+        buffer = kmap(page);
+        base = ((unsigned long long) page->index) << PAGE_CACHE_SHIFT;
+
+        err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
+        if(err != count){
+                ClearPageUptodate(page);
+                goto out;
+        }
+
+        if (base > inode->i_size)
+                inode->i_size = base;
+
+        if (PageError(page))
+                ClearPageError(page);
+        err = 0;
+
+ out:
+        kunmap(page);
+
+        unlock_page(page);
+        return err;
+}
+
+int hostfs_readpage(struct file *file, struct page *page)
+{
+        char *buffer;
+        long long start;
+        int err = 0;
+
+        start = (long long) page->index << PAGE_CACHE_SHIFT;
+        buffer = kmap(page);
+        err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer,
+                        PAGE_CACHE_SIZE);
+        if(err < 0) goto out;
+
+        memset(&buffer[err], 0, PAGE_CACHE_SIZE - err);
+
+        flush_dcache_page(page);
+        SetPageUptodate(page);
+        if (PageError(page)) ClearPageError(page);
+        err = 0;
+ out:
+        kunmap(page);
+        unlock_page(page);
+        return(err);
+}
+
+int hostfs_prepare_write(struct file *file, struct page *page,
+                         unsigned int from, unsigned int to)
+{
+        char *buffer;
+        long long start, tmp;
+        int err;
+
+        start = (long long) page->index << PAGE_CACHE_SHIFT;
+        buffer = kmap(page);
+        if(from != 0){
+                tmp = start;
+                err = read_file(FILE_HOSTFS_I(file)->fd, &tmp, buffer,
+                                from);
+                if(err < 0) goto out;
+        }
+        if(to != PAGE_CACHE_SIZE){
+                start += to;
+                err = read_file(FILE_HOSTFS_I(file)->fd, &start, buffer + to,
+                                PAGE_CACHE_SIZE - to);
+                if(err < 0) goto out;
+        }
+        err = 0;
+ out:
+        kunmap(page);
+        return(err);
+}
+
+int hostfs_commit_write(struct file *file, struct page *page, unsigned from,
+                 unsigned to)
+{
+        struct address_space *mapping = page->mapping;
+        struct inode *inode = mapping->host;
+        char *buffer;
+        long long start;
+        int err = 0;
+
+        start = (long long) (page->index << PAGE_CACHE_SHIFT) + from;
+        buffer = kmap(page);
+        err = write_file(FILE_HOSTFS_I(file)->fd, &start, buffer + from,
+                         to - from);
+        if(err > 0) err = 0;
+        if(!err && (start > inode->i_size))
+                inode->i_size = start;
+
+        kunmap(page);
+        return(err);
+}
+
+static struct address_space_operations hostfs_aops = {
+        .writepage      = hostfs_writepage,
+        .readpage       = hostfs_readpage,
+/*      .set_page_dirty = __set_page_dirty_nobuffers, */
+        .prepare_write  = hostfs_prepare_write,
+        .commit_write   = hostfs_commit_write
+};
+
+static int init_inode(struct inode *inode, struct dentry *dentry)
+{
+        char *name;
+        int type, err = -ENOMEM;
+        int maj, min;
+        dev_t rdev = 0;
+
+        if(dentry){
+                name = dentry_name(dentry, 0);
+                if(name == NULL)
+                        goto out;
+                type = file_type(name, &maj, &min);
+                /*Reencode maj and min with the kernel encoding.*/
+                rdev = MKDEV(maj, min);
+                kfree(name);
+        }
+        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 = &hostfs_dir_iops;
+        else inode->i_op = &hostfs_iops;
+
+        if(type == OS_TYPE_DIR) inode->i_fop = &hostfs_dir_fops;
+        else inode->i_fop = &hostfs_file_fops;
+
+        if(type == OS_TYPE_SYMLINK)
+                inode->i_mapping->a_ops = &hostfs_link_aops;
+        else inode->i_mapping->a_ops = &hostfs_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;
+        }
+ out:
+        return(err);
+}
+
+int hostfs_create(struct inode *dir, struct dentry *dentry, int mode,
+                 struct nameidata *nd)
+{
+        struct inode *inode;
+        char *name;
+        int error, fd;
+
+        error = -ENOMEM;
+        inode = iget(dir->i_sb, 0);
+        if(inode == NULL) goto out;
+
+        error = init_inode(inode, dentry);
+        if(error)
+                goto out_put;
+
+        error = -ENOMEM;
+        name = dentry_name(dentry, 0);
+        if(name == NULL)
+                goto out_put;
+
+        fd = file_create(name,
+                         mode & S_IRUSR, mode & S_IWUSR, mode & S_IXUSR,
+                         mode & S_IRGRP, mode & S_IWGRP, mode & S_IXGRP,
+                         mode & S_IROTH, mode & S_IWOTH, mode & S_IXOTH);
+        if(fd < 0)
+                error = fd;
+        else error = read_name(inode, name);
+
+        kfree(name);
+        if(error)
+                goto out_put;
+
+        HOSTFS_I(inode)->fd = fd;
+        HOSTFS_I(inode)->mode = FMODE_READ | FMODE_WRITE;
+        d_instantiate(dentry, inode);
+        return(0);
+
+ out_put:
+        iput(inode);
+ out:
+        return(error);
+}
+
+struct dentry *hostfs_lookup(struct inode *ino, struct dentry *dentry,
+                            struct nameidata *nd)
+{
+        struct inode *inode;
+        char *name;
+        int err;
+
+        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 == -ENOENT){
+                iput(inode);
+                inode = NULL;
+        }
+        else if(err)
+                goto out_put;
+
+        d_add(dentry, inode);
+        dentry->d_op = &hostfs_dentry_ops;
+        return(NULL);
+
+ out_put:
+        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 hostfs_link(struct dentry *to, struct inode *ino, struct dentry *from)
+{
+        char *from_name, *to_name;
+        int err;
+
+        if((from_name = inode_dentry_name(ino, from)) == NULL)
+                return(-ENOMEM);
+        to_name = dentry_name(to, 0);
+        if(to_name == NULL){
+                kfree(from_name);
+                return(-ENOMEM);
+        }
+        err = link_file(to_name, from_name);
+        kfree(from_name);
+        kfree(to_name);
+        return(err);
+}
+
+int hostfs_unlink(struct inode *ino, struct dentry *dentry)
+{
+        char *file;
+        int err;
+
+        if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
+        if(append)
+                return(-EPERM);
+
+        err = unlink_file(file);
+        kfree(file);
+        return(err);
+}
+
+int hostfs_symlink(struct inode *ino, struct dentry *dentry, const char *to)
+{
+        char *file;
+        int err;
+
+        if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
+        err = make_symlink(file, to);
+        kfree(file);
+        return(err);
+}
+
+int hostfs_mkdir(struct inode *ino, struct dentry *dentry, int mode)
+{
+        char *file;
+        int err;
+
+        if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
+        err = do_mkdir(file, mode);
+        kfree(file);
+        return(err);
+}
+
+int hostfs_rmdir(struct inode *ino, struct dentry *dentry)
+{
+        char *file;
+        int err;
+
+        if((file = inode_dentry_name(ino, dentry)) == NULL) return(-ENOMEM);
+        err = do_rmdir(file);
+        kfree(file);
+        return(err);
+}
+
+int hostfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+        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 = do_mknod(name, mode, dev);
+        if(err)
+                goto out_free;
+
+        err = read_name(inode, name);
+        kfree(name);
+        if(err)
+                goto out_put;
+
+        d_instantiate(dentry, inode);
+        return(0);
+
+ out_free:
+        kfree(name);
+ out_put:
+        iput(inode);
+ out:
+        return(err);
+}
+
+int hostfs_rename(struct inode *from_ino, struct dentry *from,
+                  struct inode *to_ino, struct dentry *to)
+{
+        char *from_name, *to_name;
+        int err;
+
+        if((from_name = inode_dentry_name(from_ino, from)) == NULL)
+                return(-ENOMEM);
+        if((to_name = inode_dentry_name(to_ino, to)) == NULL){
+                kfree(from_name);
+                return(-ENOMEM);
+        }
+        err = rename_file(from_name, to_name);
+        kfree(from_name);
+        kfree(to_name);
+        return(err);
+}
+
+void hostfs_truncate(struct inode *ino)
+{
+        not_implemented();
+}
+
+int hostfs_permission(struct inode *ino, int desired, struct nameidata *nd)
+{
+        char *name;
+        int r = 0, w = 0, x = 0, err;
+
+        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);
+
+        if (S_ISCHR(ino->i_mode) || S_ISBLK(ino->i_mode) ||
+                        S_ISFIFO(ino->i_mode) || S_ISSOCK(ino->i_mode))
+                err = 0;
+        else
+                err = access_file(name, r, w, x);
+        kfree(name);
+        if(!err)
+                err = generic_permission(ino, desired, NULL);
+        return err;
+}
+
+int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+        struct hostfs_iattr attrs;
+        char *name;
+        int err;
+
+        err = inode_change_ok(dentry->d_inode, attr);
+        if (err)
+                return err;
+
+        if(append)
+                attr->ia_valid &= ~ATTR_SIZE;
+
+        attrs.ia_valid = 0;
+        if(attr->ia_valid & ATTR_MODE){
+                attrs.ia_valid |= HOSTFS_ATTR_MODE;
+                attrs.ia_mode = attr->ia_mode;
+        }
+        if(attr->ia_valid & ATTR_UID){
+                if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) &&
+                   (attr->ia_uid == 0))
+                        attr->ia_uid = getuid();
+                attrs.ia_valid |= HOSTFS_ATTR_UID;
+                attrs.ia_uid = attr->ia_uid;
+        }
+        if(attr->ia_valid & ATTR_GID){
+                if((dentry->d_inode->i_sb->s_dev == ROOT_DEV) &&
+                   (attr->ia_gid == 0))
+                        attr->ia_gid = getgid();
+                attrs.ia_valid |= HOSTFS_ATTR_GID;
+                attrs.ia_gid = attr->ia_gid;
+        }
+        if(attr->ia_valid & ATTR_SIZE){
+                attrs.ia_valid |= HOSTFS_ATTR_SIZE;
+                attrs.ia_size = attr->ia_size;
+        }
+        if(attr->ia_valid & ATTR_ATIME){
+                attrs.ia_valid |= HOSTFS_ATTR_ATIME;
+                attrs.ia_atime = attr->ia_atime;
+        }
+        if(attr->ia_valid & ATTR_MTIME){
+                attrs.ia_valid |= HOSTFS_ATTR_MTIME;
+                attrs.ia_mtime = attr->ia_mtime;
+        }
+        if(attr->ia_valid & ATTR_CTIME){
+                attrs.ia_valid |= HOSTFS_ATTR_CTIME;
+                attrs.ia_ctime = attr->ia_ctime;
+        }
+        if(attr->ia_valid & ATTR_ATIME_SET){
+                attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
+        }
+        if(attr->ia_valid & ATTR_MTIME_SET){
+                attrs.ia_valid |= HOSTFS_ATTR_MTIME_SET;
+        }
+        name = dentry_name(dentry, 0);
+        if(name == NULL) return(-ENOMEM);
+        err = set_attr(name, &attrs);
+        kfree(name);
+        if(err)
+                return(err);
+
+        return(inode_setattr(dentry->d_inode, attr));
+}
+
+int hostfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
+           struct kstat *stat)
+{
+        generic_fillattr(dentry->d_inode, stat);
+        return(0);
+}
+
+static struct inode_operations hostfs_iops = {
+        .create         = hostfs_create,
+        .link           = hostfs_link,
+        .unlink         = hostfs_unlink,
+        .symlink        = hostfs_symlink,
+        .mkdir          = hostfs_mkdir,
+        .rmdir          = hostfs_rmdir,
+        .mknod          = hostfs_mknod,
+        .rename         = hostfs_rename,
+        .truncate       = hostfs_truncate,
+        .permission     = hostfs_permission,
+        .setattr        = hostfs_setattr,
+        .getattr        = hostfs_getattr,
+};
+
+static struct inode_operations hostfs_dir_iops = {
+        .create         = hostfs_create,
+        .lookup         = hostfs_lookup,
+        .link           = hostfs_link,
+        .unlink         = hostfs_unlink,
+        .symlink        = hostfs_symlink,
+        .mkdir          = hostfs_mkdir,
+        .rmdir          = hostfs_rmdir,
+        .mknod          = hostfs_mknod,
+        .rename         = hostfs_rename,
+        .truncate       = hostfs_truncate,
+        .permission     = hostfs_permission,
+        .setattr        = hostfs_setattr,
+        .getattr        = hostfs_getattr,
+};
+
+int hostfs_link_readpage(struct file *file, struct page *page)
+{
+        char *buffer, *name;
+        long long start;
+        int err;
+
+        start = page->index << PAGE_CACHE_SHIFT;
+        buffer = kmap(page);
+        name = inode_name(page->mapping->host, 0);
+        if(name == NULL) return(-ENOMEM);
+        err = do_readlink(name, buffer, PAGE_CACHE_SIZE);
+        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 struct address_space_operations hostfs_link_aops = {
+        .readpage       = hostfs_link_readpage,
+};
+
+static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)
+{
+        struct inode *root_inode;
+        char *name, *data = d;
+        int err;
+
+        sb->s_blocksize = 1024;
+        sb->s_blocksize_bits = 10;
+        sb->s_magic = HOSTFS_SUPER_MAGIC;
+        sb->s_op = &hostfs_sbops;
+
+        if((data == NULL) || (*data == '\0'))
+                data = root_ino;
+
+        err = -ENOMEM;
+        name = kmalloc(strlen(data) + 1, GFP_KERNEL);
+        if(name == NULL)
+                goto out;
+
+        strcpy(name, data);
+
+        root_inode = iget(sb, 0);
+        if(root_inode == NULL)
+                goto out_free;
+
+        err = init_inode(root_inode, NULL);
+        if(err)
+                goto out_put;
+
+        HOSTFS_I(root_inode)->host_filename = name;
+
+        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;
+
+        return(0);
+
+ out_put:
+        iput(root_inode);
+ out_free:
+        kfree(name);
+ out:
+        return(err);
+}
+
+static struct super_block *hostfs_read_sb(struct file_system_type *type,
+                                             int flags, const char *dev_name,
+                                             void *data)
+{
+        return(get_sb_nodev(type, flags, data, hostfs_fill_sb_common));
+}
+
+static struct file_system_type hostfs_type = {
+        .owner          = THIS_MODULE,
+        .name           = "hostfs",
+        .get_sb         = hostfs_read_sb,
+        .kill_sb        = kill_anon_super,
+        .fs_flags       = 0,
+};
+
+static int __init init_hostfs(void)
+{
+        return(register_filesystem(&hostfs_type));
+}
+
+static void __exit exit_hostfs(void)
+{
+        unregister_filesystem(&hostfs_type);
+}
+
+module_init(init_hostfs)
+module_exit(exit_hostfs)
+MODULE_LICENSE("GPL");
+
+/*
+ * 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:
+ */