diff options
Diffstat (limited to 'fs/ecryptfs/super.c')
| -rw-r--r-- | fs/ecryptfs/super.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c new file mode 100644 index 00000000000..c337c0410fb --- /dev/null +++ b/fs/ecryptfs/super.c @@ -0,0 +1,198 @@ +/** + * 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/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 *ecryptfs_inode; + struct inode *inode = NULL; + + ecryptfs_inode = kmem_cache_alloc(ecryptfs_inode_info_cache, + SLAB_KERNEL); + if (unlikely(!ecryptfs_inode)) + goto out; + ecryptfs_init_crypt_stat(&ecryptfs_inode->crypt_stat); + inode = &ecryptfs_inode->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. + * 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); + ecryptfs_destruct_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_destruct_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_umount_begin + * + * Called in do_umount(). + */ +static void ecryptfs_umount_begin(struct vfsmount *vfsmnt, int flags) +{ + struct vfsmount *lower_mnt = + ecryptfs_dentry_to_lower_mnt(vfsmnt->mnt_sb->s_root); + struct super_block *lower_sb; + + mntput(lower_mnt); + lower_sb = lower_mnt->mnt_sb; + if (lower_sb->s_op->umount_begin) + lower_sb->s_op->umount_begin(lower_mnt, flags); +} + +/** + * 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; +} + +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, + .umount_begin = ecryptfs_umount_begin, + .show_options = ecryptfs_show_options +}; |