cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dentry.c (2020B)

      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 */
     31static 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
     52struct kmem_cache *ecryptfs_dentry_info_cache;
     53
     54static 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 */
     66static 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
     75const struct dentry_operations ecryptfs_dops = {
     76	.d_revalidate = ecryptfs_d_revalidate,
     77	.d_release = ecryptfs_d_release,
     78};