| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 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 | */ |
| 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 | |
| 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 | */ |
| 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 | }; |