[PATCH] ecryptfs: fs/Makefile and fs/Kconfig

eCryptfs is a stacked cryptographic filesystem for Linux.  It is derived from
Erez Zadok's Cryptfs, implemented through the FiST framework for generating
stacked filesystems.  eCryptfs extends Cryptfs to provide advanced key
management and policy features.  eCryptfs stores cryptographic metadata in the
header of each file written, so that encrypted files can be copied between
hosts; the file will be decryptable with the proper key, and there is no need
to keep track of any additional information aside from what is already in the
encrypted file itself.

[akpm@osdl.org: updates for ongoing API changes]
[bunk@stusta.de: cleanups]
[akpm@osdl.org: alpha build fix]
[akpm@osdl.org: cleanups]
[tytso@mit.edu: inode-diet updates]
[pbadari@us.ibm.com: generic_file_*_read/write() interface updates]
[rdunlap@xenotime.net: printk format fixes]
[akpm@osdl.org: make slab creation and teardown table-driven]
Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1079 insertions, 0 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
new file mode 100644
index 00000000000..efdd2b7b62d
--- /dev/null
+++ b/fs/ecryptfs/inode.c
@@ -0,0 +1,1079 @@
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompsion <mcthomps@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/file.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/crypto.h>
+#include "ecryptfs_kernel.h"
+
+static struct dentry *lock_parent(struct dentry *dentry)
+{
+	struct dentry *dir;
+
+	dir = dget(dentry->d_parent);
+	mutex_lock(&(dir->d_inode->i_mutex));
+	return dir;
+}
+
+static void unlock_parent(struct dentry *dentry)
+{
+	mutex_unlock(&(dentry->d_parent->d_inode->i_mutex));
+	dput(dentry->d_parent);
+}
+
+static void unlock_dir(struct dentry *dir)
+{
+	mutex_unlock(&dir->d_inode->i_mutex);
+	dput(dir);
+}
+
+void ecryptfs_copy_inode_size(struct inode *dst, const struct inode *src)
+{
+	i_size_write(dst, i_size_read((struct inode *)src));
+	dst->i_blocks = src->i_blocks;
+}
+
+void ecryptfs_copy_attr_atime(struct inode *dest, const struct inode *src)
+{
+	dest->i_atime = src->i_atime;
+}
+
+static void ecryptfs_copy_attr_times(struct inode *dest,
+				     const struct inode *src)
+{
+	dest->i_atime = src->i_atime;
+	dest->i_mtime = src->i_mtime;
+	dest->i_ctime = src->i_ctime;
+}
+
+static void ecryptfs_copy_attr_timesizes(struct inode *dest,
+					 const struct inode *src)
+{
+	dest->i_atime = src->i_atime;
+	dest->i_mtime = src->i_mtime;
+	dest->i_ctime = src->i_ctime;
+	ecryptfs_copy_inode_size(dest, src);
+}
+
+void ecryptfs_copy_attr_all(struct inode *dest, const struct inode *src)
+{
+	dest->i_mode = src->i_mode;
+	dest->i_nlink = src->i_nlink;
+	dest->i_uid = src->i_uid;
+	dest->i_gid = src->i_gid;
+	dest->i_rdev = src->i_rdev;
+	dest->i_atime = src->i_atime;
+	dest->i_mtime = src->i_mtime;
+	dest->i_ctime = src->i_ctime;
+	dest->i_blkbits = src->i_blkbits;
+	dest->i_flags = src->i_flags;
+}
+
+/**
+ * ecryptfs_create_underlying_file
+ * @lower_dir_inode: inode of the parent in the lower fs of the new file
+ * @lower_dentry: New file's dentry in the lower fs
+ * @ecryptfs_dentry: New file's dentry in ecryptfs
+ * @mode: The mode of the new file
+ * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
+ *
+ * Creates the file in the lower file system.
+ *
+ * Returns zero on success; non-zero on error condition
+ */
+static int
+ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
+				struct dentry *dentry, int mode,
+				struct nameidata *nd)
+{
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	struct dentry *dentry_save;
+	struct vfsmount *vfsmount_save;
+	int rc;
+
+	dentry_save = nd->dentry;
+	vfsmount_save = nd->mnt;
+	nd->dentry = lower_dentry;
+	nd->mnt = lower_mnt;
+	rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
+	nd->dentry = dentry_save;
+	nd->mnt = vfsmount_save;
+	return rc;
+}
+
+/**
+ * ecryptfs_do_create
+ * @directory_inode: inode of the new file's dentry's parent in ecryptfs
+ * @ecryptfs_dentry: New file's dentry in ecryptfs
+ * @mode: The mode of the new file
+ * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
+ *
+ * Creates the underlying file and the eCryptfs inode which will link to
+ * it. It will also update the eCryptfs directory inode to mimic the
+ * stat of the lower directory inode.
+ *
+ * Returns zero on success; non-zero on error condition
+ */
+static int
+ecryptfs_do_create(struct inode *directory_inode,
+		   struct dentry *ecryptfs_dentry, int mode,
+		   struct nameidata *nd)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct dentry *lower_dir_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+	lower_dir_dentry = lock_parent(lower_dentry);
+	if (unlikely(IS_ERR(lower_dir_dentry))) {
+		ecryptfs_printk(KERN_ERR, "Error locking directory of "
+				"dentry\n");
+		rc = PTR_ERR(lower_dir_dentry);
+		goto out;
+	}
+	rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
+					     ecryptfs_dentry, mode, nd);
+	if (unlikely(rc)) {
+		ecryptfs_printk(KERN_ERR,
+				"Failure to create underlying file\n");
+		goto out_lock;
+	}
+	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
+				directory_inode->i_sb, 0);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
+		goto out_lock;
+	}
+	ecryptfs_copy_attr_timesizes(directory_inode,
+				     lower_dir_dentry->d_inode);
+out_lock:
+	unlock_dir(lower_dir_dentry);
+out:
+	return rc;
+}
+
+/**
+ * grow_file
+ * @ecryptfs_dentry: the ecryptfs dentry
+ * @lower_file: The lower file
+ * @inode: The ecryptfs inode
+ * @lower_inode: The lower inode
+ *
+ * This is the code which will grow the file to its correct size.
+ */
+static int grow_file(struct dentry *ecryptfs_dentry, struct file *lower_file,
+		     struct inode *inode, struct inode *lower_inode)
+{
+	int rc = 0;
+	struct file fake_file;
+	struct ecryptfs_file_info tmp_file_info;
+
+	memset(&fake_file, 0, sizeof(fake_file));
+	fake_file.f_dentry = ecryptfs_dentry;
+	memset(&tmp_file_info, 0, sizeof(tmp_file_info));
+	ecryptfs_set_file_private(&fake_file, &tmp_file_info);
+	ecryptfs_set_file_lower(&fake_file, lower_file);
+	rc = ecryptfs_fill_zeros(&fake_file, 1);
+	if (rc) {
+		ECRYPTFS_SET_FLAG(
+			ecryptfs_inode_to_private(inode)->crypt_stat.flags,
+			ECRYPTFS_SECURITY_WARNING);
+		ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
+				"in file; rc = [%d]\n", rc);
+		goto out;
+	}
+	i_size_write(inode, 0);
+	ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
+	ECRYPTFS_SET_FLAG(ecryptfs_inode_to_private(inode)->crypt_stat.flags,
+			  ECRYPTFS_NEW_FILE);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_initialize_file
+ *
+ * Cause the file to be changed from a basic empty file to an ecryptfs
+ * file with a header and first data page.
+ *
+ * Returns zero on success
+ */
+static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
+{
+	int rc = 0;
+	int lower_flags;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	struct dentry *lower_dentry;
+	struct dentry *tlower_dentry = NULL;
+	struct file *lower_file;
+	struct inode *inode, *lower_inode;
+	struct vfsmount *lower_mnt;
+
+	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+	ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
+			lower_dentry->d_name.name);
+	inode = ecryptfs_dentry->d_inode;
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	tlower_dentry = dget(lower_dentry);
+	if (!tlower_dentry) {
+		rc = -ENOMEM;
+		ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry\n");
+		goto out;
+	}
+	lower_flags = ((O_CREAT | O_WRONLY | O_TRUNC) & O_ACCMODE) | O_RDWR;
+#if BITS_PER_LONG != 32
+	lower_flags |= O_LARGEFILE;
+#endif
+	lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
+	mntget(lower_mnt);
+	/* Corresponding fput() at end of this function */
+	lower_file = dentry_open(tlower_dentry, lower_mnt, lower_flags);
+	if (IS_ERR(lower_file)) {
+		rc = PTR_ERR(lower_file);
+		ecryptfs_printk(KERN_ERR,
+				"Error opening dentry; rc = [%i]\n", rc);
+		goto out;
+	}
+	/* fput(lower_file) should handle the puts if we do this */
+	lower_file->f_dentry = tlower_dentry;
+	lower_file->f_vfsmnt = lower_mnt;
+	lower_inode = tlower_dentry->d_inode;
+	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
+		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
+		ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
+		goto out_fput;
+	}
+	ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
+	ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
+	rc = ecryptfs_new_file_context(ecryptfs_dentry);
+	if (rc) {
+		ecryptfs_printk(KERN_DEBUG, "Error creating new file "
+				"context\n");
+		goto out_fput;
+	}
+	rc = ecryptfs_write_headers(ecryptfs_dentry, lower_file);
+	if (rc) {
+		ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
+		goto out_fput;
+	}
+	rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
+out_fput:
+	fput(lower_file);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_create
+ * @dir: The inode of the directory in which to create the file.
+ * @dentry: The eCryptfs dentry
+ * @mode: The mode of the new file.
+ * @nd: nameidata
+ *
+ * Creates a new file.
+ *
+ * Returns zero on success; non-zero on error condition
+ */
+static int
+ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
+		int mode, struct nameidata *nd)
+{
+	int rc;
+
+	rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
+	if (unlikely(rc)) {
+		ecryptfs_printk(KERN_WARNING, "Failed to create file in"
+				"lower filesystem\n");
+		goto out;
+	}
+	/* At this point, a file exists on "disk"; we need to make sure
+	 * that this on disk file is prepared to be an ecryptfs file */
+	rc = ecryptfs_initialize_file(ecryptfs_dentry);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_lookup
+ * @dir: inode
+ * @dentry: The dentry
+ * @nd: nameidata, may be NULL
+ *
+ * Find a file on disk. If the file does not exist, then we'll add it to the
+ * dentry cache and continue on to read it from the disk.
+ */
+static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
+				      struct nameidata *nd)
+{
+	int rc = 0;
+	struct dentry *lower_dir_dentry;
+	struct dentry *lower_dentry;
+	struct vfsmount *lower_mnt;
+	struct dentry *tlower_dentry = NULL;
+	char *encoded_name;
+	unsigned int encoded_namelen;
+	struct ecryptfs_crypt_stat *crypt_stat = NULL;
+	char *page_virt = NULL;
+	struct inode *lower_inode;
+	u64 file_size;
+
+	lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
+	dentry->d_op = &ecryptfs_dops;
+	if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
+	    || (dentry->d_name.len == 2 && !strcmp(dentry->d_name.name, "..")))
+		goto out_drop;
+	encoded_namelen = ecryptfs_encode_filename(crypt_stat,
+						   dentry->d_name.name,
+						   dentry->d_name.len,
+						   &encoded_name);
+	if (encoded_namelen < 0) {
+		rc = encoded_namelen;
+		goto out_drop;
+	}
+	ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
+			"= [%d]\n", encoded_name, encoded_namelen);
+	lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
+				      encoded_namelen - 1);
+	kfree(encoded_name);
+	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
+	if (IS_ERR(lower_dentry)) {
+		ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
+		rc = PTR_ERR(lower_dentry);
+		goto out_drop;
+	}
+	ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
+       		"d_name.name = [%s]\n", lower_dentry,
+		lower_dentry->d_name.name);
+	lower_inode = lower_dentry->d_inode;
+	ecryptfs_copy_attr_atime(dir, lower_dir_dentry->d_inode);
+	BUG_ON(!atomic_read(&lower_dentry->d_count));
+	ecryptfs_set_dentry_private(dentry,
+				    kmem_cache_alloc(ecryptfs_dentry_info_cache,
+						     SLAB_KERNEL));
+	if (!ecryptfs_dentry_to_private(dentry)) {
+		rc = -ENOMEM;
+		ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
+				"to allocate ecryptfs_dentry_info struct\n");
+		goto out_dput;
+	}
+	ecryptfs_set_dentry_lower(dentry, lower_dentry);
+	ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
+	if (!lower_dentry->d_inode) {
+		/* We want to add because we couldn't find in lower */
+		d_add(dentry, NULL);
+		goto out;
+	}
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 1);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error interposing\n");
+		goto out_dput;
+	}
+	if (S_ISDIR(lower_inode->i_mode)) {
+		ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
+		goto out;
+	}
+	if (S_ISLNK(lower_inode->i_mode)) {
+		ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
+		goto out;
+	}
+	if (!nd) {
+		ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
+				"as we *think* we are about to unlink\n");
+		goto out;
+	}
+	tlower_dentry = dget(lower_dentry);
+	if (!tlower_dentry || IS_ERR(tlower_dentry)) {
+		rc = -ENOMEM;
+		ecryptfs_printk(KERN_ERR, "Cannot dget lower_dentry\n");
+		goto out_dput;
+	}
+	/* Released in this function */
+	page_virt =
+	    (char *)kmem_cache_alloc(ecryptfs_header_cache_2,
+				     SLAB_USER);
+	if (!page_virt) {
+		rc = -ENOMEM;
+		ecryptfs_printk(KERN_ERR,
+				"Cannot ecryptfs_kmalloc a page\n");
+		goto out_dput;
+	}
+	memset(page_virt, 0, PAGE_CACHE_SIZE);
+	rc = ecryptfs_read_header_region(page_virt, tlower_dentry, nd->mnt);
+	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
+	if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED))
+		ecryptfs_set_default_sizes(crypt_stat);
+	if (rc) {
+		rc = 0;
+		ecryptfs_printk(KERN_WARNING, "Error reading header region;"
+				" assuming unencrypted\n");
+	} else {
+		if (!contains_ecryptfs_marker(page_virt
+					      + ECRYPTFS_FILE_SIZE_BYTES)) {
+			kmem_cache_free(ecryptfs_header_cache_2, page_virt);
+			goto out;
+		}
+		memcpy(&file_size, page_virt, sizeof(file_size));
+		file_size = be64_to_cpu(file_size);
+		i_size_write(dentry->d_inode, (loff_t)file_size);
+	}
+	kmem_cache_free(ecryptfs_header_cache_2, page_virt);
+	goto out;
+
+out_dput:
+	dput(lower_dentry);
+	if (tlower_dentry)
+		dput(tlower_dentry);
+out_drop:
+	d_drop(dentry);
+out:
+	return ERR_PTR(rc);
+}
+
+static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
+			 struct dentry *new_dentry)
+{
+	struct dentry *lower_old_dentry;
+	struct dentry *lower_new_dentry;
+	struct dentry *lower_dir_dentry;
+	u64 file_size_save;
+	int rc;
+
+	file_size_save = i_size_read(old_dentry->d_inode);
+	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
+	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
+	dget(lower_old_dentry);
+	dget(lower_new_dentry);
+	lower_dir_dentry = lock_parent(lower_new_dentry);
+	rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
+		      lower_new_dentry);
+	if (rc || !lower_new_dentry->d_inode)
+		goto out_lock;
+	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
+	if (rc)
+		goto out_lock;
+	ecryptfs_copy_attr_timesizes(dir, lower_new_dentry->d_inode);
+	old_dentry->d_inode->i_nlink =
+		ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
+	i_size_write(new_dentry->d_inode, file_size_save);
+out_lock:
+	unlock_dir(lower_dir_dentry);
+	dput(lower_new_dentry);
+	dput(lower_old_dentry);
+	if (!new_dentry->d_inode)
+		d_drop(new_dentry);
+	return rc;
+}
+
+static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int rc = 0;
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
+
+	lock_parent(lower_dentry);
+	rc = vfs_unlink(lower_dir_inode, lower_dentry);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error in vfs_unlink\n");
+		goto out_unlock;
+	}
+	ecryptfs_copy_attr_times(dir, lower_dir_inode);
+	dentry->d_inode->i_nlink =
+		ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
+	dentry->d_inode->i_ctime = dir->i_ctime;
+out_unlock:
+	unlock_parent(lower_dentry);
+	return rc;
+}
+
+static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
+			    const char *symname)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct dentry *lower_dir_dentry;
+	umode_t mode;
+	char *encoded_symname;
+	unsigned int encoded_symlen;
+	struct ecryptfs_crypt_stat *crypt_stat = NULL;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	dget(lower_dentry);
+	lower_dir_dentry = lock_parent(lower_dentry);
+	mode = S_IALLUGO;
+	encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
+						  strlen(symname),
+						  &encoded_symname);
+	if (encoded_symlen < 0) {
+		rc = encoded_symlen;
+		goto out_lock;
+	}
+	rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
+			 encoded_symname, mode);
+	kfree(encoded_symname);
+	if (rc || !lower_dentry->d_inode)
+		goto out_lock;
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+	if (rc)
+		goto out_lock;
+	ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
+out_lock:
+	unlock_dir(lower_dir_dentry);
+	dput(lower_dentry);
+	if (!dentry->d_inode)
+		d_drop(dentry);
+	return rc;
+}
+
+static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct dentry *lower_dir_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	lower_dir_dentry = lock_parent(lower_dentry);
+	rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
+	if (rc || !lower_dentry->d_inode)
+		goto out;
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+	if (rc)
+		goto out;
+	ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
+	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
+out:
+	unlock_dir(lower_dir_dentry);
+	if (!dentry->d_inode)
+		d_drop(dentry);
+	return rc;
+}
+
+static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	int rc = 0;
+	struct dentry *tdentry = NULL;
+	struct dentry *lower_dentry;
+	struct dentry *tlower_dentry = NULL;
+	struct dentry *lower_dir_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!(tdentry = dget(dentry))) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_ERR, "Error dget'ing dentry [%p]\n",
+				dentry);
+		goto out;
+	}
+	lower_dir_dentry = lock_parent(lower_dentry);
+	if (!(tlower_dentry = dget(lower_dentry))) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_ERR, "Error dget'ing lower_dentry "
+				"[%p]\n", lower_dentry);
+		goto out;
+	}
+	rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
+	if (!rc) {
+		d_delete(tlower_dentry);
+		tlower_dentry = NULL;
+	}
+	ecryptfs_copy_attr_times(dir, lower_dir_dentry->d_inode);
+	dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
+	unlock_dir(lower_dir_dentry);
+	if (!rc)
+		d_drop(dentry);
+out:
+	if (tdentry)
+		dput(tdentry);
+	if (tlower_dentry)
+		dput(tlower_dentry);
+	return rc;
+}
+
+static int
+ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct dentry *lower_dir_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	lower_dir_dentry = lock_parent(lower_dentry);
+	rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
+	if (rc || !lower_dentry->d_inode)
+		goto out;
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
+	if (rc)
+		goto out;
+	ecryptfs_copy_attr_timesizes(dir, lower_dir_dentry->d_inode);
+out:
+	unlock_dir(lower_dir_dentry);
+	if (!dentry->d_inode)
+		d_drop(dentry);
+	return rc;
+}
+
+static int
+ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+		struct inode *new_dir, struct dentry *new_dentry)
+{
+	int rc;
+	struct dentry *lower_old_dentry;
+	struct dentry *lower_new_dentry;
+	struct dentry *lower_old_dir_dentry;
+	struct dentry *lower_new_dir_dentry;
+
+	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
+	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
+	dget(lower_old_dentry);
+	dget(lower_new_dentry);
+	lower_old_dir_dentry = dget_parent(lower_old_dentry);
+	lower_new_dir_dentry = dget_parent(lower_new_dentry);
+	lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
+			lower_new_dir_dentry->d_inode, lower_new_dentry);
+	if (rc)
+		goto out_lock;
+	ecryptfs_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
+	if (new_dir != old_dir)
+		ecryptfs_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
+out_lock:
+	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	dput(lower_new_dentry);
+	dput(lower_old_dentry);
+	return rc;
+}
+
+static int
+ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	char *decoded_name;
+	char *lower_buf;
+	mm_segment_t old_fs;
+	struct ecryptfs_crypt_stat *crypt_stat;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!lower_dentry->d_inode->i_op ||
+	    !lower_dentry->d_inode->i_op->readlink) {
+		rc = -EINVAL;
+		goto out;
+	}
+	/* Released in this function */
+	lower_buf = kmalloc(bufsiz, GFP_KERNEL);
+	if (lower_buf == NULL) {
+		ecryptfs_printk(KERN_ERR, "Out of memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
+			"lower_dentry->d_name.name = [%s]\n",
+			lower_dentry->d_name.name);
+	rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
+						   (char __user *)lower_buf,
+						   bufsiz);
+	set_fs(old_fs);
+	if (rc >= 0) {
+		crypt_stat = NULL;
+		rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
+					      &decoded_name);
+		if (rc == -ENOMEM)
+			goto out_free_lower_buf;
+		if (rc > 0) {
+			ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
+					"to userspace: [%*s]\n", rc,
+					decoded_name);
+			if (copy_to_user(buf, decoded_name, rc))
+				rc = -EFAULT;
+		}
+		kfree(decoded_name);
+		ecryptfs_copy_attr_atime(dentry->d_inode,
+					 lower_dentry->d_inode);
+	}
+out_free_lower_buf:
+	kfree(lower_buf);
+out:
+	return rc;
+}
+
+static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	char *buf;
+	int len = PAGE_SIZE, rc;
+	mm_segment_t old_fs;
+
+	/* Released in ecryptfs_put_link(); only release here on error */
+	buf = kmalloc(len, GFP_KERNEL);
+	if (!buf) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
+			"dentry->d_name.name = [%s]\n", dentry->d_name.name);
+	rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
+	buf[rc] = '\0';
+	set_fs(old_fs);
+	if (rc < 0)
+		goto out_free;
+	rc = 0;
+	nd_set_link(nd, buf);
+	goto out;
+out_free:
+	kfree(buf);
+out:
+	return ERR_PTR(rc);
+}
+
+static void
+ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
+{
+	/* Free the char* */
+	kfree(nd_get_link(nd));
+}
+
+/**
+ * upper_size_to_lower_size
+ * @crypt_stat: Crypt_stat associated with file
+ * @upper_size: Size of the upper file
+ *
+ * Calculate the requried size of the lower file based on the
+ * specified size of the upper file. This calculation is based on the
+ * number of headers in the underlying file and the extent size.
+ *
+ * Returns Calculated size of the lower file.
+ */
+static loff_t
+upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
+			 loff_t upper_size)
+{
+	loff_t lower_size;
+
+	lower_size = ( crypt_stat->header_extent_size
+		       * crypt_stat->num_header_extents_at_front );
+	if (upper_size != 0) {
+		loff_t num_extents;
+
+		num_extents = upper_size >> crypt_stat->extent_shift;
+		if (upper_size & ~crypt_stat->extent_mask)
+			num_extents++;
+		lower_size += (num_extents * crypt_stat->extent_size);
+	}
+	return lower_size;
+}
+
+/**
+ * ecryptfs_truncate
+ * @dentry: The ecryptfs layer dentry
+ * @new_length: The length to expand the file to
+ *
+ * Function to handle truncations modifying the size of the file. Note
+ * that the file sizes are interpolated. When expanding, we are simply
+ * writing strings of 0's out. When truncating, we need to modify the
+ * underlying file size according to the page index interpolations.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
+{
+	int rc = 0;
+	struct inode *inode = dentry->d_inode;
+	struct dentry *lower_dentry;
+	struct vfsmount *lower_mnt;
+	struct file fake_ecryptfs_file, *lower_file = NULL;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	loff_t i_size = i_size_read(inode);
+	loff_t lower_size_before_truncate;
+	loff_t lower_size_after_truncate;
+
+	if (unlikely((new_length == i_size)))
+		goto out;
+	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
+	/* Set up a fake ecryptfs file, this is used to interface with
+	 * the file in the underlying filesystem so that the
+	 * truncation has an effect there as well. */
+	memset(&fake_ecryptfs_file, 0, sizeof(fake_ecryptfs_file));
+	fake_ecryptfs_file.f_dentry = dentry;
+	/* Released at out_free: label */
+	ecryptfs_set_file_private(&fake_ecryptfs_file,
+				  kmem_cache_alloc(ecryptfs_file_info_cache,
+						   SLAB_KERNEL));
+	if (unlikely(!ecryptfs_file_to_private(&fake_ecryptfs_file))) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	/* This dget & mntget is released through fput at out_fput: */
+	dget(lower_dentry);
+	lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
+	mntget(lower_mnt);
+	lower_file = dentry_open(lower_dentry, lower_mnt, O_RDWR);
+	if (unlikely(IS_ERR(lower_file))) {
+		rc = PTR_ERR(lower_file);
+		goto out_free;
+	}
+	ecryptfs_set_file_lower(&fake_ecryptfs_file, lower_file);
+	/* Switch on growing or shrinking file */
+	if (new_length > i_size) {
+		rc = ecryptfs_fill_zeros(&fake_ecryptfs_file, new_length);
+		if (rc) {
+			ecryptfs_printk(KERN_ERR,
+					"Problem with fill_zeros\n");
+			goto out_fput;
+		}
+		i_size_write(inode, new_length);
+		rc = ecryptfs_write_inode_size_to_header(lower_file,
+							 lower_dentry->d_inode,
+							 inode);
+		if (rc) {
+			ecryptfs_printk(KERN_ERR,
+					"Problem with ecryptfs_write"
+					"_inode_size\n");
+			goto out_fput;
+		}
+	} else { /* new_length < i_size_read(inode) */
+		vmtruncate(inode, new_length);
+		ecryptfs_write_inode_size_to_header(lower_file,
+						    lower_dentry->d_inode,
+						    inode);
+		/* We are reducing the size of the ecryptfs file, and need to
+		 * know if we need to reduce the size of the lower file. */
+		lower_size_before_truncate =
+		    upper_size_to_lower_size(crypt_stat, i_size);
+		lower_size_after_truncate =
+		    upper_size_to_lower_size(crypt_stat, new_length);
+		if (lower_size_after_truncate < lower_size_before_truncate)
+			vmtruncate(lower_dentry->d_inode,
+				   lower_size_after_truncate);
+	}
+	/* Update the access times */
+	lower_dentry->d_inode->i_mtime = lower_dentry->d_inode->i_ctime
+		= CURRENT_TIME;
+	mark_inode_dirty_sync(inode);
+out_fput:
+	fput(lower_file);
+out_free:
+	if (ecryptfs_file_to_private(&fake_ecryptfs_file))
+		kmem_cache_free(ecryptfs_file_info_cache,
+				ecryptfs_file_to_private(&fake_ecryptfs_file));
+out:
+	return rc;
+}
+
+static int
+ecryptfs_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+	int rc;
+
+        if (nd) {
+		struct vfsmount *vfsmnt_save = nd->mnt;
+		struct dentry *dentry_save = nd->dentry;
+
+		nd->mnt = ecryptfs_dentry_to_lower_mnt(nd->dentry);
+		nd->dentry = ecryptfs_dentry_to_lower(nd->dentry);
+		rc = permission(ecryptfs_inode_to_lower(inode), mask, nd);
+		nd->mnt = vfsmnt_save;
+		nd->dentry = dentry_save;
+        } else
+		rc = permission(ecryptfs_inode_to_lower(inode), mask, NULL);
+        return rc;
+}
+
+/**
+ * ecryptfs_setattr
+ * @dentry: dentry handle to the inode to modify
+ * @ia: Structure with flags of what to change and values
+ *
+ * Updates the metadata of an inode. If the update is to the size
+ * i.e. truncation, then ecryptfs_truncate will handle the size modification
+ * of both the ecryptfs inode and the lower inode.
+ *
+ * All other metadata changes will be passed right to the lower filesystem,
+ * and we will just update our inode to look like the lower.
+ */
+static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+	struct inode *inode;
+	struct inode *lower_inode;
+	struct ecryptfs_crypt_stat *crypt_stat;
+
+	crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	inode = dentry->d_inode;
+	lower_inode = ecryptfs_inode_to_lower(inode);
+	if (ia->ia_valid & ATTR_SIZE) {
+		ecryptfs_printk(KERN_DEBUG,
+				"ia->ia_valid = [0x%x] ATTR_SIZE" " = [0x%x]\n",
+				ia->ia_valid, ATTR_SIZE);
+		rc = ecryptfs_truncate(dentry, ia->ia_size);
+		/* ecryptfs_truncate handles resizing of the lower file */
+		ia->ia_valid &= ~ATTR_SIZE;
+		ecryptfs_printk(KERN_DEBUG, "ia->ia_valid = [%x]\n",
+				ia->ia_valid);
+		if (rc < 0)
+			goto out;
+	}
+	rc = notify_change(lower_dentry, ia);
+out:
+	ecryptfs_copy_attr_all(inode, lower_inode);
+	return rc;
+}
+
+static int
+ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
+		  size_t size, int flags)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!lower_dentry->d_inode->i_op->setxattr) {
+		rc = -ENOSYS;
+		goto out;
+	}
+	mutex_lock(&lower_dentry->d_inode->i_mutex);
+	rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, name, value,
+						   size, flags);
+	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+out:
+	return rc;
+}
+
+static ssize_t
+ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
+		  size_t size)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!lower_dentry->d_inode->i_op->getxattr) {
+		rc = -ENOSYS;
+		goto out;
+	}
+	mutex_lock(&lower_dentry->d_inode->i_mutex);
+	rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
+						   size);
+	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+out:
+	return rc;
+}
+
+static ssize_t
+ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!lower_dentry->d_inode->i_op->listxattr) {
+		rc = -ENOSYS;
+		goto out;
+	}
+	mutex_lock(&lower_dentry->d_inode->i_mutex);
+	rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
+	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+out:
+	return rc;
+}
+
+static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!lower_dentry->d_inode->i_op->removexattr) {
+		rc = -ENOSYS;
+		goto out;
+	}
+	mutex_lock(&lower_dentry->d_inode->i_mutex);
+	rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
+	mutex_unlock(&lower_dentry->d_inode->i_mutex);
+out:
+	return rc;
+}
+
+int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
+{
+	if ((ecryptfs_inode_to_lower(inode)
+	     == (struct inode *)candidate_lower_inode))
+		return 1;
+	else
+		return 0;
+}
+
+int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
+{
+	ecryptfs_init_inode(inode, (struct inode *)lower_inode);
+	return 0;
+}
+
+struct inode_operations ecryptfs_symlink_iops = {
+	.readlink = ecryptfs_readlink,
+	.follow_link = ecryptfs_follow_link,
+	.put_link = ecryptfs_put_link,
+	.permission = ecryptfs_permission,
+	.setattr = ecryptfs_setattr,
+	.setxattr = ecryptfs_setxattr,
+	.getxattr = ecryptfs_getxattr,
+	.listxattr = ecryptfs_listxattr,
+	.removexattr = ecryptfs_removexattr
+};
+
+struct inode_operations ecryptfs_dir_iops = {
+	.create = ecryptfs_create,
+	.lookup = ecryptfs_lookup,
+	.link = ecryptfs_link,
+	.unlink = ecryptfs_unlink,
+	.symlink = ecryptfs_symlink,
+	.mkdir = ecryptfs_mkdir,
+	.rmdir = ecryptfs_rmdir,
+	.mknod = ecryptfs_mknod,
+	.rename = ecryptfs_rename,
+	.permission = ecryptfs_permission,
+	.setattr = ecryptfs_setattr,
+	.setxattr = ecryptfs_setxattr,
+	.getxattr = ecryptfs_getxattr,
+	.listxattr = ecryptfs_listxattr,
+	.removexattr = ecryptfs_removexattr
+};
+
+struct inode_operations ecryptfs_main_iops = {
+	.permission = ecryptfs_permission,
+	.setattr = ecryptfs_setattr,
+	.setxattr = ecryptfs_setxattr,
+	.getxattr = ecryptfs_getxattr,
+	.listxattr = ecryptfs_listxattr,
+	.removexattr = ecryptfs_removexattr
+};