/**
* eCryptfs: Linux filesystem encryption layer
*
* Copyright (C) 1997-2003 Erez Zadok
* Copyright (C) 2001-2003 Stony Brook University
* Copyright (C) 2004-2006 International Business Machines Corp.
* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
* Michael C. Thompson <mcthomps@us.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/key.h>
#include <linux/seq_file.h>
#include <linux/file.h>
#include <linux/crypto.h>
#include "ecryptfs_kernel.h"
struct kmem_cache *ecryptfs_inode_info_cache;
/**
* ecryptfs_alloc_inode - allocate an ecryptfs inode
* @sb: Pointer to the ecryptfs super block
*
* Called to bring an inode into existence.
*
* Only handle allocation, setting up structures should be done in
* ecryptfs_read_inode. This is because the kernel, between now and
* then, will 0 out the private data pointer.
*
* Returns a pointer to a newly allocated inode, NULL otherwise
*/
static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
{
struct ecryptfs_inode_info *inode_info;
struct inode *inode = NULL;
inode_info = kmem_cache_alloc(ecryptfs_inode_info_cache, GFP_KERNEL);
if (unlikely(!inode_info))
goto out;
ecryptfs_init_crypt_stat(&inode_info->crypt_stat);
mutex_init(&inode_info->lower_file_mutex);
inode_info->lower_file = NULL;
inode = &inode_info->vfs_inode;
out:
return inode;
}
/**
* ecryptfs_destroy_inode
* @inode: The ecryptfs inode
*
* This is used during the final destruction of the inode. All
* allocation of memory related to the inode, including allocated
* memory in the crypt_stat struct, will be released here. This
* function also fput()'s the persistent file for the lower inode.
* There should be no chance that this deallocation will be missed.
*/
static void ecryptfs_destroy_inode(struct inode *inode)
{
struct ecryptfs_inode_info *inode_info;
inode_info = ecryptfs_inode_to_private(inode);
mutex_lock(&inode_info->lower_file_mutex);
if (inode_info->lower_file) {
struct dentry *lower_dentry =
inode_info->lower_file->f_dentry;
BUG_ON(!lower_dentry);
if (lower_dentry->d_inode) {
fput(inode_info->lower_file);
inode_info->lower_file = NULL;
d_drop(lower_dentry);
d_delete(lower_dentry);
}
}
mutex_unlock(&inode_info->lower_file_mutex);
ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
}
/**
* ecryptfs_init_inode
* @inode: The ecryptfs inode
*
* Set up the ecryptfs inode.
*/
void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode)
{
ecryptfs_set_inode_lower(inode, lower_inode);
inode->i_ino = lower_inode->i_ino;
inode->i_version++;
inode->i_op = &ecryptfs_main_iops;
inode->i_fop = &ecryptfs_main_fops;
inode->i_mapping->a_ops = &ecryptfs_aops;
}
/**
* ecryptfs_put_super
* @sb: Pointer to the ecryptfs super block
*
* Final actions when unmounting a file system.
* This will handle deallocation and release of our private data.
*/
static void ecryptfs_put_super(struct super_block *sb)
{
struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
ecryptfs_set_superblock_private(sb, NULL);
}
/**
* ecryptfs_statfs
* @sb: The ecryptfs super block
* @buf: The struct kstatfs to fill in with stats
*
* Get the filesystem statistics. Currently, we let this pass right through
* to the lower filesystem and take no action ourselves.
*/
static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
return vfs_statfs(ecryptfs_dentry_to_lower(dentry), buf);
}
/**
* ecryptfs_clear_inode
* @inode - The ecryptfs inode
*
* Called by iput() when the inode reference count reached zero
* and the inode is not hashed anywhere. Used to clear anything
* that needs to be, before the inode is completely destroyed and put
* on the inode free list. We use this to drop out reference to the
* lower inode.
*/
static void ecryptfs_clear_inode(struct inode *inode)
{
iput(ecryptfs_inode_to_lower(inode));
}
/**
* ecryptfs_show_options
*
* Prints the directory we are currently mounted over.
* Returns zero on success; non-zero otherwise
*/
static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
{
struct super_block *sb = mnt->mnt_sb;
struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root);
struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root);
char *tmp_page;
char *path;
int rc = 0;
tmp_page = (char *)__get_free_page(GFP_KERNEL);
if (!tmp_page) {
rc = -ENOMEM;
goto out;
}
path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE);
if (IS_ERR(path)) {
rc = PTR_ERR(path);
goto out;
}
seq_printf(m, ",dir=%s", path);
free_page((unsigned long)tmp_page);
out:
return rc;
}
const struct super_operations ecryptfs_sops = {
.alloc_inode = ecryptfs_alloc_inode,
.destroy_inode = ecryptfs_destroy_inode,
.drop_inode = generic_delete_inode,
.put_super = ecryptfs_put_super,
.statfs = ecryptfs_statfs,
.remount_fs = NULL,
.clear_inode = ecryptfs_clear_inode,
.show_options = ecryptfs_show_options
};
