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(inode, 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(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(&p->rcu, 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