[PATCH 8/12: eCryptfs] Dentry operations

[Phillip Hellewell <phillip@hellewell.homeip.net>]

eCryptfs dentry operations.

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

---

 dentry.c |  105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 105 insertions(+)
--- linux-2.6.15-rc1-mm1/fs/ecryptfs/dentry.c	1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.15-rc1-mm1-ecryptfs/fs/ecryptfs/dentry.c	2005-11-18 11:20:09.000000000 -0600
@@ -0,0 +1,105 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (c) 1997-2003 Erez Zadok
+ * Copyright (c) 2001-2003 Stony Brook University
+ * Copyright (c) 2005 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"
+
+/**
+ * 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.
+ *
+ *
+ * @param dentry	ecryptfs dentry
+ * @param nd		
+ * @return 		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;
+
+	ecryptfs_printk(1, KERN_NOTICE, "Enter; dentry->d_name.name = [%s]\n",
+			dentry->d_name.name);
+	lower_dentry = ecryptfs_lower_dentry(dentry);
+	if (!lower_dentry) {
+		err = 0;
+		goto out;
+	}
+	if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
+		goto out;
+	/* Call the lower dentry's d_revalidate (assuming it has one) */
+	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:
+	ecryptfs_printk(1, KERN_NOTICE, "Exit; err = [%d]\n", err);
+	return err;
+}
+
+kmem_cache_t *ecryptfs_dentry_info_cache;
+
+/* Notes:
+ * Called when a dentry is really deallocated
+ * Sanity check? wrapper around ecryptfs_dput()
+ */
+static void ecryptfs_d_release(struct dentry *dentry)
+{
+	struct dentry *lower_dentry;
+
+	ecryptfs_printk(1, KERN_NOTICE, "Enter; dentry->d_name->name = [%s]\n",
+			dentry->d_name.name);
+	if (!dentry) {
+		ecryptfs_printk(0, KERN_ERR, "NULL dentry\n");
+		goto out;
+	}
+	if (!ECRYPTFS_DENTRY_TO_PRIVATE(dentry)) {
+		ecryptfs_printk(1, KERN_ERR, "dentry without private data: "
+				"[%*s]\n", dentry->d_name.len,
+				dentry->d_name.name);
+		goto out;
+	}
+	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);
+out:
+	ecryptfs_printk(1, KERN_NOTICE, "Exit\n");
+	return;
+}
+
+struct dentry_operations ecryptfs_dops = {
+	.d_revalidate = ecryptfs_d_revalidate,
+	.d_release = ecryptfs_d_release,
+};