1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * 4 * Copyright (C) 1997-2003 Erez Zadok 5 * Copyright (C) 2001-2003 Stony Brook University 6 * Copyright (C) 2004-2006 International Business Machines Corp. 7 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License as 11 * published by the Free Software Foundation; either version 2 of the 12 * License, or (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 22 * 02111-1307, USA. 23 */ 24 25 #include <linux/dcache.h> 26 #include <linux/namei.h> 27 #include <linux/mount.h> 28 #include <linux/fs_stack.h> 29 #include <linux/slab.h> 30 #include "ecryptfs_kernel.h" 31 32 /** 33 * ecryptfs_d_revalidate - revalidate an ecryptfs dentry 34 * @dentry: The ecryptfs dentry 35 * @nd: The associated nameidata 36 * 37 * Called when the VFS needs to revalidate a dentry. This 38 * is called whenever a name lookup finds a dentry in the 39 * dcache. Most filesystems leave this as NULL, because all their 40 * dentries in the dcache are valid. 41 * 42 * Returns 1 if valid, 0 otherwise. 43 * 44 */ 45 static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd) 46 { 47 struct dentry *lower_dentry; 48 struct vfsmount *lower_mnt; 49 struct dentry *dentry_save; 50 struct vfsmount *vfsmount_save; 51 int rc = 1; 52 53 if (nd->flags & LOOKUP_RCU) 54 return -ECHILD; 55 56 lower_dentry = ecryptfs_dentry_to_lower(dentry); 57 lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry); 58 if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate) 59 goto out; 60 dentry_save = nd->path.dentry; 61 vfsmount_save = nd->path.mnt; 62 nd->path.dentry = lower_dentry; 63 nd->path.mnt = lower_mnt; 64 rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd); 65 nd->path.dentry = dentry_save; 66 nd->path.mnt = vfsmount_save; 67 if (dentry->d_inode) { 68 struct inode *lower_inode = 69 ecryptfs_inode_to_lower(dentry->d_inode); 70 71 fsstack_copy_attr_all(dentry->d_inode, lower_inode); 72 } 73 out: 74 return rc; 75 } 76 77 struct kmem_cache *ecryptfs_dentry_info_cache; 78 79 /** 80 * ecryptfs_d_release 81 * @dentry: The ecryptfs dentry 82 * 83 * Called when a dentry is really deallocated. 84 */ 85 static void ecryptfs_d_release(struct dentry *dentry) 86 { 87 if (ecryptfs_dentry_to_private(dentry)) { 88 if (ecryptfs_dentry_to_lower(dentry)) { 89 dput(ecryptfs_dentry_to_lower(dentry)); 90 mntput(ecryptfs_dentry_to_lower_mnt(dentry)); 91 } 92 kmem_cache_free(ecryptfs_dentry_info_cache, 93 ecryptfs_dentry_to_private(dentry)); 94 } 95 return; 96 } 97 98 const struct dentry_operations ecryptfs_dops = { 99 .d_revalidate = ecryptfs_d_revalidate, 100 .d_release = ecryptfs_d_release, 101 }; 102