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 * @flags: lookup flags 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 */ ecryptfs_d_revalidate(struct dentry * dentry,unsigned int flags)45 static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags) 46 { 47 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 48 int rc = 1; 49 50 if (flags & LOOKUP_RCU) 51 return -ECHILD; 52 53 if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE) 54 rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags); 55 56 if (d_really_is_positive(dentry)) { 57 struct inode *inode = d_inode(dentry); 58 59 fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode)); 60 if (!inode->i_nlink) 61 return 0; 62 } 63 return rc; 64 } 65 66 struct kmem_cache *ecryptfs_dentry_info_cache; 67 ecryptfs_dentry_free_rcu(struct rcu_head * head)68 static void ecryptfs_dentry_free_rcu(struct rcu_head *head) 69 { 70 kmem_cache_free(ecryptfs_dentry_info_cache, 71 container_of(head, struct ecryptfs_dentry_info, rcu)); 72 } 73 74 /** 75 * ecryptfs_d_release 76 * @dentry: The ecryptfs dentry 77 * 78 * Called when a dentry is really deallocated. 79 */ ecryptfs_d_release(struct dentry * dentry)80 static void ecryptfs_d_release(struct dentry *dentry) 81 { 82 struct ecryptfs_dentry_info *p = dentry->d_fsdata; 83 if (p) { 84 path_put(&p->lower_path); 85 call_rcu(&p->rcu, ecryptfs_dentry_free_rcu); 86 } 87 } 88 89 const struct dentry_operations ecryptfs_dops = { 90 .d_revalidate = ecryptfs_d_revalidate, 91 .d_release = ecryptfs_d_release, 92 }; 93