/* [<][>][^][v][top][bottom][index][help] */
DEFINITIONS
This source file includes following definitions.
- HOSTFS_I
- hostfs_d_delete
- hostfs_args
- dentry_name
- inode_name
- read_name
- follow_link
- hostfs_read_inode
- hostfs_iget
- hostfs_statfs
- hostfs_alloc_inode
- hostfs_delete_inode
- hostfs_destroy_inode
- hostfs_show_options
- hostfs_readdir
- hostfs_file_open
- hostfs_fsync
- hostfs_writepage
- hostfs_readpage
- hostfs_write_begin
- hostfs_write_end
- init_inode
- hostfs_create
- hostfs_lookup
- inode_dentry_name
- hostfs_link
- hostfs_unlink
- hostfs_symlink
- hostfs_mkdir
- hostfs_rmdir
- hostfs_mknod
- hostfs_rename
- hostfs_permission
- hostfs_setattr
- hostfs_link_readpage
- hostfs_fill_sb_common
- hostfs_read_sb
- init_hostfs
- exit_hostfs
/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*
* Ported the filesystem routines to 2.5.
* 2003-02-10 Petr Baudis <pasky@ucw.cz>
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include "hostfs.h"
#include "init.h"
#include "kern.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_path.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 const struct inode_operations hostfs_iops;
static const struct inode_operations hostfs_dir_iops;
static const 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, -1);
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_blocks = i_blocks;
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 hostfs_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;
}
static struct inode *hostfs_iget(struct super_block *sb)
{
struct inode *inode;
long ret;
inode = iget_locked(sb, 0);
if (!inode)
return ERR_PTR(-ENOMEM);
if (inode->i_state & I_NEW) {
ret = hostfs_read_inode(inode);
if (ret < 0) {
iget_failed(inode);
return ERR_PTR(ret);
}
unlock_new_inode(inode);
}
return inode;
}
int hostfs_statfs(struct dentry *dentry, 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(dentry->d_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)
{
truncate_inode_pages(&inode->i_data, 0);
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)
{
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 int hostfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
{
struct inode *root = vfs->mnt_sb->s_root->d_inode;
const char *root_path = HOSTFS_I(root)->host_filename;
size_t offset = strlen(root_ino) + 1;
if (strlen(root_path) > offset)
seq_printf(seq, ",%s", root_path + offset);
return 0;
}
static const 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,
.statfs = hostfs_statfs,
.show_options = hostfs_show_options,
};
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_path.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_path.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 fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync);
}
static const struct file_operations hostfs_file_fops = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.splice_read = generic_file_splice_read,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.write = do_sync_write,
.mmap = generic_file_mmap,
.open = hostfs_file_open,
.release = NULL,
.fsync = hostfs_fsync,
};
static const 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_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
*pagep = __grab_cache_page(mapping, index);
if (!*pagep)
return -ENOMEM;
return 0;
}
int hostfs_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
struct inode *inode = mapping->host;
void *buffer;
unsigned from = pos & (PAGE_CACHE_SIZE - 1);
int err;
buffer = kmap(page);
err = write_file(FILE_HOSTFS_I(file)->fd, &pos, buffer + from, copied);
kunmap(page);
if (!PageUptodate(page) && err == PAGE_CACHE_SIZE)
SetPageUptodate(page);
/*
* If err > 0, write_file has added err to pos, so we are comparing
* i_size against the last byte written.
*/
if (err > 0 && (pos > inode->i_size))
inode->i_size = pos;
unlock_page(page);
page_cache_release(page);
return err;
}
static const struct address_space_operations hostfs_aops = {
.writepage = hostfs_writepage,
.readpage = hostfs_readpage,
.set_page_dirty = __set_page_dirty_nobuffers,
.write_begin = hostfs_write_begin,
.write_end = hostfs_write_end,
};
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;
inode = hostfs_iget(dir->i_sb);
if (IS_ERR(inode)) {
error = PTR_ERR(inode);
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;
inode = hostfs_iget(ino->i_sb);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
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;
inode = hostfs_iget(dir->i_sb);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
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, MAJOR(dev), MINOR(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;
}
int hostfs_permission(struct inode *ino, int desired)
{
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;
int fd = HOSTFS_I(dentry->d_inode)->fd;
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) {
attrs.ia_valid |= HOSTFS_ATTR_UID;
attrs.ia_uid = attr->ia_uid;
}
if (attr->ia_valid & ATTR_GID) {
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, fd);
kfree(name);
if (err)
return err;
return inode_setattr(dentry->d_inode, attr);
}
static const 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,
.permission = hostfs_permission,
.setattr = hostfs_setattr,
};
static const 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,
.permission = hostfs_permission,
.setattr = hostfs_setattr,
};
int hostfs_link_readpage(struct file *file, struct page *page)
{
char *buffer, *name;
int err;
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 const 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 *host_root_path, *req_root = d;
int err;
sb->s_blocksize = 1024;
sb->s_blocksize_bits = 10;
sb->s_magic = HOSTFS_SUPER_MAGIC;
sb->s_op = &hostfs_sbops;
/* NULL is printed as <NULL> by sprintf: avoid that. */
if (req_root == NULL)
req_root = "";
err = -ENOMEM;
host_root_path = kmalloc(strlen(root_ino) + 1
+ strlen(req_root) + 1, GFP_KERNEL);
if (host_root_path == NULL)
goto out;
sprintf(host_root_path, "%s/%s", root_ino, req_root);
root_inode = hostfs_iget(sb);
if (IS_ERR(root_inode)) {
err = PTR_ERR(root_inode);
goto out_free;
}
err = init_inode(root_inode, NULL);
if (err)
goto out_put;
HOSTFS_I(root_inode)->host_filename = host_root_path;
/*
* Avoid that in the error path, iput(root_inode) frees again
* host_root_path through hostfs_destroy_inode!
*/
host_root_path = NULL;
err = -ENOMEM;
sb->s_root = d_alloc_root(root_inode);
if (sb->s_root == NULL)
goto out_put;
err = hostfs_read_inode(root_inode);
if (err) {
/* No iput in this case because the dput does that for us */
dput(sb->s_root);
sb->s_root = NULL;
goto out;
}
return 0;
out_put:
iput(root_inode);
out_free:
kfree(host_root_path);
out:
return err;
}
static int hostfs_read_sb(struct file_system_type *type,
int flags, const char *dev_name,
void *data, struct vfsmount *mnt)
{
return get_sb_nodev(type, flags, data, hostfs_fill_sb_common, mnt);
}
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");