1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * eCryptfs: Linux filesystem encryption layer |
4 | * |
5 | * Copyright (C) 1997-2003 Erez Zadok |
6 | * Copyright (C) 2001-2003 Stony Brook University |
7 | * Copyright (C) 2004-2006 International Business Machines Corp. |
8 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
9 | */ |
10 | |
11 | #include <linux/dcache.h> |
12 | #include <linux/namei.h> |
13 | #include <linux/mount.h> |
14 | #include <linux/fs_stack.h> |
15 | #include <linux/slab.h> |
16 | #include "ecryptfs_kernel.h" |
17 | |
18 | /** |
19 | * ecryptfs_d_revalidate - revalidate an ecryptfs dentry |
20 | * @dentry: The ecryptfs dentry |
21 | * @flags: lookup flags |
22 | * |
23 | * Called when the VFS needs to revalidate a dentry. This |
24 | * is called whenever a name lookup finds a dentry in the |
25 | * dcache. Most filesystems leave this as NULL, because all their |
26 | * dentries in the dcache are valid. |
27 | * |
28 | * Returns 1 if valid, 0 otherwise. |
29 | * |
30 | */ |
31 | static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags) |
32 | { |
33 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); |
34 | int rc = 1; |
35 | |
36 | if (flags & LOOKUP_RCU) |
37 | return -ECHILD; |
38 | |
39 | if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE) |
40 | rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags); |
41 | |
42 | if (d_really_is_positive(dentry)) { |
43 | struct inode *inode = d_inode(dentry); |
44 | |
45 | fsstack_copy_attr_all(dest: inode, src: ecryptfs_inode_to_lower(inode)); |
46 | if (!inode->i_nlink) |
47 | return 0; |
48 | } |
49 | return rc; |
50 | } |
51 | |
52 | struct kmem_cache *ecryptfs_dentry_info_cache; |
53 | |
54 | static void ecryptfs_dentry_free_rcu(struct rcu_head *head) |
55 | { |
56 | kmem_cache_free(s: ecryptfs_dentry_info_cache, |
57 | container_of(head, struct ecryptfs_dentry_info, rcu)); |
58 | } |
59 | |
60 | /** |
61 | * ecryptfs_d_release |
62 | * @dentry: The ecryptfs dentry |
63 | * |
64 | * Called when a dentry is really deallocated. |
65 | */ |
66 | static void ecryptfs_d_release(struct dentry *dentry) |
67 | { |
68 | struct ecryptfs_dentry_info *p = dentry->d_fsdata; |
69 | if (p) { |
70 | path_put(&p->lower_path); |
71 | call_rcu(head: &p->rcu, func: ecryptfs_dentry_free_rcu); |
72 | } |
73 | } |
74 | |
75 | const struct dentry_operations ecryptfs_dops = { |
76 | .d_revalidate = ecryptfs_d_revalidate, |
77 | .d_release = ecryptfs_d_release, |
78 | }; |
79 | |