[PATCH 7/13: eCryptfs] Dentry operations

Phillip Hellewell
2006-05-13T03:45:07Z

This is the 7th patch in a series of 13 constituting the kernel
components of the eCryptfs cryptographic filesystem.

eCryptfs dentry operations.

Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>

---

dentry.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 91 insertions(+)

Index: linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/dentry.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.17-rc3-mm1-ecryptfs/fs/ecryptfs/dentry.c 2006-05-12 20:00:26.000000000 -0600
@@ -0,0 +1,91 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
+ * @dentry: The ecryptfs dentry
+ * @nd: The associated nameidata
+ *
+ * Called when the VFS needs to revalidate a dentry. This
+ * is called whenever a name lookup finds a dentry in the
+ * dcache. Most filesystems leave this as NULL, because all their
+ * dentries in the dcache are valid.
+ *
+ * Returns 1 if valid, 0 otherwise.
+ *
+ */
+static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+ int err = 1;
+ struct dentry *lower_dentry;
+ struct dentry *saved_dentry;
+ struct vfsmount *saved_vfsmount;
+
+ lower_dentry = ecryptfs_dentry_to_lower(dentry);
+ if (!lower_dentry) {
+ err = 0;
+ goto out;
+ }
+ if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
+ goto out;
+ saved_dentry = nd->dentry;
+ saved_vfsmount = nd->mnt;
+ nd->dentry = lower_dentry;
+ nd->mnt = ecryptfs_superblock_to_private(dentry->d_sb)->lower_mnt;
+ err = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
+ nd->dentry = saved_dentry;
+ nd->mnt = saved_vfsmount;
+out:
+ return err;
+}
+
+struct kmem_cache *ecryptfs_dentry_info_cache;
+
+/**
+ * ecryptfs_d_release
+ * @dentry: The ecryptfs dentry
+ *
+ * Called when a dentry is really deallocated.
+ */
+static void ecryptfs_d_release(struct dentry *dentry)
+{
+ struct dentry *lower_dentry;
+
+ lower_dentry = ecryptfs_dentry_to_lower(dentry);
+ if (ecryptfs_dentry_to_private(dentry))
+ kmem_cache_free(ecryptfs_dentry_info_cache,
+ ecryptfs_dentry_to_private(dentry));
+ if (lower_dentry)
+ dput(lower_dentry);
+ return;
+}
+
+struct dentry_operations ecryptfs_dops = {
+ .d_revalidate = ecryptfs_d_revalidate,
+ .d_release = ecryptfs_d_release,
+};