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 * @dir: inode of expected parent 21 * @name: expected name 22 * @dentry: dentry to revalidate 23 * @flags: lookup flags 24 * 25 * Called when the VFS needs to revalidate a dentry. This 26 * is called whenever a name lookup finds a dentry in the 27 * dcache. Most filesystems leave this as NULL, because all their 28 * dentries in the dcache are valid. 29 * 30 * Returns 1 if valid, 0 otherwise. 31 * 32 */ 33 static int ecryptfs_d_revalidate(struct inode *dir, const struct qstr *name, 34 struct dentry *dentry, unsigned int flags) 35 { 36 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); 37 int rc = 1; 38 39 if (flags & LOOKUP_RCU) 40 return -ECHILD; 41 42 if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE) { 43 struct inode *lower_dir = ecryptfs_inode_to_lower(dir); 44 struct name_snapshot n; 45 46 take_dentry_name_snapshot(&n, lower_dentry); 47 rc = lower_dentry->d_op->d_revalidate(lower_dir, &n.name, 48 lower_dentry, flags); 49 release_dentry_name_snapshot(&n); 50 } 51 52 if (d_really_is_positive(dentry)) { 53 struct inode *inode = d_inode(dentry); 54 55 fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode)); 56 if (!inode->i_nlink) 57 return 0; 58 } 59 return rc; 60 } 61 62 struct kmem_cache *ecryptfs_dentry_info_cache; 63 64 static void ecryptfs_dentry_free_rcu(struct rcu_head *head) 65 { 66 kmem_cache_free(ecryptfs_dentry_info_cache, 67 container_of(head, struct ecryptfs_dentry_info, rcu)); 68 } 69 70 /** 71 * ecryptfs_d_release 72 * @dentry: The ecryptfs dentry 73 * 74 * Called when a dentry is really deallocated. 75 */ 76 static void ecryptfs_d_release(struct dentry *dentry) 77 { 78 struct ecryptfs_dentry_info *p = dentry->d_fsdata; 79 if (p) { 80 path_put(&p->lower_path); 81 call_rcu(&p->rcu, ecryptfs_dentry_free_rcu); 82 } 83 } 84 85 const struct dentry_operations ecryptfs_dops = { 86 .d_revalidate = ecryptfs_d_revalidate, 87 .d_release = ecryptfs_d_release, 88 }; 89