fs/ecryptfs/file.c - kernel/msm-4.9 - Gitiles

 /**
  * eCryptfs: Linux filesystem encryption layer
  *
  * Copyright (C) 1997-2004 Erez Zadok
  * Copyright (C) 2001-2004 Stony Brook University
  * Copyright (C) 2004-2007 International Business Machines Corp.
  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
  *   		Michael C. Thompson <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/poll.h>
 #include <linux/slab.h>
 #include <linux/mount.h>
 #include <linux/pagemap.h>
 #include <linux/security.h>
 #include <linux/compat.h>
 #include <linux/fs_stack.h>
 #include <linux/smp_lock.h>
 #include "ecryptfs_kernel.h"

 /**
  * ecryptfs_read_update_atime
  *
  * generic_file_read updates the atime of upper layer inode.  But, it
  * doesn't give us a chance to update the atime of the lower layer
  * inode.  This function is a wrapper to generic_file_read.  It
  * updates the atime of the lower level inode if generic_file_read
  * returns without any errors. This is to be used only for file reads.
  * The function to be used for directory reads is ecryptfs_read.
  */
 static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
 				const struct iovec *iov,
 				unsigned long nr_segs, loff_t pos)
 {
 	int rc;
 	struct dentry *lower_dentry;
 	struct vfsmount *lower_vfsmount;
 	struct file *file = iocb->ki_filp;

 	rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
 	/*
 	 * Even though this is a async interface, we need to wait
 	 * for IO to finish to update atime
 	 */
 	if (-EIOCBQUEUED == rc)
 		rc = wait_on_sync_kiocb(iocb);
 	if (rc >= 0) {
 		lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
 		lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
 		touch_atime(lower_vfsmount, lower_dentry);
 	}
 	return rc;
 }

 struct ecryptfs_getdents_callback {
 	void *dirent;
 	struct dentry *dentry;
 	filldir_t filldir;
 	int filldir_called;
 	int entries_written;
 };

 /* Inspired by generic filldir in fs/readdir.c */
 static int
 ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
 		 loff_t offset, u64 ino, unsigned int d_type)
 {
 	struct ecryptfs_getdents_callback *buf =
 	    (struct ecryptfs_getdents_callback *)dirent;
 	size_t name_size;
 	char *name;
 	int rc;

 	buf->filldir_called++;
 	rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
 						  buf->dentry, lower_name,
 						  lower_namelen);
 	if (rc) {
 		printk(KERN_ERR "%s: Error attempting to decode and decrypt "
 		       "filename [%s]; rc = [%d]\n", __func__, lower_name,
 		       rc);
 		goto out;
 	}
 	rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
 	kfree(name);
 	if (rc >= 0)
 		buf->entries_written++;
 out:
 	return rc;
 }

 /**
  * ecryptfs_readdir
  * @file: The eCryptfs directory file
  * @dirent: Directory entry handle
  * @filldir: The filldir callback function
  */
 static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 {
 	int rc;
 	struct file *lower_file;
 	struct inode *inode;
 	struct ecryptfs_getdents_callback buf;

 	lower_file = ecryptfs_file_to_lower(file);
 	lower_file->f_pos = file->f_pos;
 	inode = file->f_path.dentry->d_inode;
 	memset(&buf, 0, sizeof(buf));
 	buf.dirent = dirent;
 	buf.dentry = file->f_path.dentry;
 	buf.filldir = filldir;
 	buf.filldir_called = 0;
 	buf.entries_written = 0;
 	rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
 	file->f_pos = lower_file->f_pos;
 	if (rc < 0)
 		goto out;
 	if (buf.filldir_called && !buf.entries_written)
 		goto out;
 	if (rc >= 0)
 		fsstack_copy_attr_atime(inode,
 					lower_file->f_path.dentry->d_inode);
 out:
 	return rc;
 }

 struct kmem_cache *ecryptfs_file_info_cache;

 /**
  * ecryptfs_open
  * @inode: inode speciying file to open
  * @file: Structure to return filled in
  *
  * Opens the file specified by inode.
  *
  * Returns zero on success; non-zero otherwise
  */
 static int ecryptfs_open(struct inode *inode, struct file *file)
 {
 	int rc = 0;
 	struct ecryptfs_crypt_stat *crypt_stat = NULL;
 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 	struct dentry *ecryptfs_dentry = file->f_path.dentry;
 	/* Private value of ecryptfs_dentry allocated in
 	 * ecryptfs_lookup() */
 	struct dentry *lower_dentry;
 	struct ecryptfs_file_info *file_info;

 	mount_crypt_stat = &ecryptfs_superblock_to_private(
 		ecryptfs_dentry->d_sb)->mount_crypt_stat;
 	if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 	    && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
 		|| (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
 		|| (file->f_flags & O_APPEND))) {
 		printk(KERN_WARNING "Mount has encrypted view enabled; "
 		       "files may only be read\n");
 		rc = -EPERM;
 		goto out;
 	}
 	/* Released in ecryptfs_release or end of function if failure */
 	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
 	ecryptfs_set_file_private(file, file_info);
 	if (!file_info) {
 		ecryptfs_printk(KERN_ERR,
 				"Error attempting to allocate memory\n");
 		rc = -ENOMEM;
 		goto out;
 	}
 	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
 	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 	mutex_lock(&crypt_stat->cs_mutex);
 	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
 		ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
 		/* Policy code enabled in future release */
 		crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
 				      | ECRYPTFS_ENCRYPTED);
 	}
 	mutex_unlock(&crypt_stat->cs_mutex);
 	if (!ecryptfs_inode_to_private(inode)->lower_file) {
 		rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
 		if (rc) {
 			printk(KERN_ERR "%s: Error attempting to initialize "
 			       "the persistent file for the dentry with name "
 			       "[%s]; rc = [%d]\n", __func__,
 			       ecryptfs_dentry->d_name.name, rc);
 			goto out;
 		}
 	}
 	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
 	    && !(file->f_flags & O_RDONLY)) {
 		rc = -EPERM;
 		printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
 		       "file must hence be opened RO\n", __func__);
 		goto out;
 	}
 	ecryptfs_set_file_lower(
 		file, ecryptfs_inode_to_private(inode)->lower_file);
 	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
 		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
 		mutex_lock(&crypt_stat->cs_mutex);
 		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 		mutex_unlock(&crypt_stat->cs_mutex);
 		rc = 0;
 		goto out;
 	}
 	mutex_lock(&crypt_stat->cs_mutex);
 	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
 	    || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
 		rc = ecryptfs_read_metadata(ecryptfs_dentry);
 		if (rc) {
 			ecryptfs_printk(KERN_DEBUG,
 					"Valid headers not found\n");
 			if (!(mount_crypt_stat->flags
 			      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
 				rc = -EIO;
 				printk(KERN_WARNING "Either the lower file "
 				       "is not in a valid eCryptfs format, "
 				       "or the key could not be retrieved. "
 				       "Plaintext passthrough mode is not "
 				       "enabled; returning -EIO\n");
 				mutex_unlock(&crypt_stat->cs_mutex);
 				goto out_free;
 			}
 			rc = 0;
 			crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
 			mutex_unlock(&crypt_stat->cs_mutex);
 			goto out;
 		}
 	}
 	mutex_unlock(&crypt_stat->cs_mutex);
 	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
 			"size: [0x%.16x]\n", inode, inode->i_ino,
 			i_size_read(inode));
 	goto out;
 out_free:
 	kmem_cache_free(ecryptfs_file_info_cache,
 			ecryptfs_file_to_private(file));
 out:
 	return rc;
 }

 static int ecryptfs_flush(struct file *file, fl_owner_t td)
 {
 	int rc = 0;
 	struct file *lower_file = NULL;

 	lower_file = ecryptfs_file_to_lower(file);
 	if (lower_file->f_op && lower_file->f_op->flush)
 		rc = lower_file->f_op->flush(lower_file, td);
 	return rc;
 }

 static int ecryptfs_release(struct inode *inode, struct file *file)
 {
 	kmem_cache_free(ecryptfs_file_info_cache,
 			ecryptfs_file_to_private(file));
 	return 0;
 }

 static int
 ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 {
 	return vfs_fsync(ecryptfs_file_to_lower(file),
 			 ecryptfs_dentry_to_lower(dentry),
 			 datasync);
 }

 static int ecryptfs_fasync(int fd, struct file *file, int flag)
 {
 	int rc = 0;
 	struct file *lower_file = NULL;

 	lock_kernel();
 	lower_file = ecryptfs_file_to_lower(file);
 	if (lower_file->f_op && lower_file->f_op->fasync)
 		rc = lower_file->f_op->fasync(fd, lower_file, flag);
 	unlock_kernel();
 	return rc;
 }

 static int ecryptfs_ioctl(struct inode *inode, struct file *file,
 			  unsigned int cmd, unsigned long arg);

 const struct file_operations ecryptfs_dir_fops = {
 	.readdir = ecryptfs_readdir,
 	.ioctl = ecryptfs_ioctl,
 	.open = ecryptfs_open,
 	.flush = ecryptfs_flush,
 	.release = ecryptfs_release,
 	.fsync = ecryptfs_fsync,
 	.fasync = ecryptfs_fasync,
 	.splice_read = generic_file_splice_read,
 };

 const struct file_operations ecryptfs_main_fops = {
 	.llseek = generic_file_llseek,
 	.read = do_sync_read,
 	.aio_read = ecryptfs_read_update_atime,
 	.write = do_sync_write,
 	.aio_write = generic_file_aio_write,
 	.readdir = ecryptfs_readdir,
 	.ioctl = ecryptfs_ioctl,
 	.mmap = generic_file_mmap,
 	.open = ecryptfs_open,
 	.flush = ecryptfs_flush,
 	.release = ecryptfs_release,
 	.fsync = ecryptfs_fsync,
 	.fasync = ecryptfs_fasync,
 	.splice_read = generic_file_splice_read,
 };

 static int
 ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	       unsigned long arg)
 {
 	int rc = 0;
 	struct file *lower_file = NULL;

 	if (ecryptfs_file_to_private(file))
 		lower_file = ecryptfs_file_to_lower(file);
 	if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
 		rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
 					     lower_file, cmd, arg);
 	else
 		rc = -ENOTTY;
 	return rc;
 }
	/**
	* eCryptfs: Linux filesystem encryption layer
	*
	* Copyright (C) 1997-2004 Erez Zadok
	* Copyright (C) 2001-2004 Stony Brook University
	* Copyright (C) 2004-2007 International Business Machines Corp.
	* Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
	* Michael C. Thompson <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/poll.h>
	#include <linux/slab.h>
	#include <linux/mount.h>
	#include <linux/pagemap.h>
	#include <linux/security.h>
	#include <linux/compat.h>
	#include <linux/fs_stack.h>
	#include <linux/smp_lock.h>
	#include "ecryptfs_kernel.h"

	/**
	* ecryptfs_read_update_atime
	*
	* generic_file_read updates the atime of upper layer inode. But, it
	* doesn't give us a chance to update the atime of the lower layer
	* inode. This function is a wrapper to generic_file_read. It
	* updates the atime of the lower level inode if generic_file_read
	* returns without any errors. This is to be used only for file reads.
	* The function to be used for directory reads is ecryptfs_read.
	*/
	static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
	const struct iovec *iov,
	unsigned long nr_segs, loff_t pos)
	{
	int rc;
	struct dentry *lower_dentry;
	struct vfsmount *lower_vfsmount;
	struct file *file = iocb->ki_filp;

	rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
	/*
	* Even though this is a async interface, we need to wait
	* for IO to finish to update atime
	*/
	if (-EIOCBQUEUED == rc)
	rc = wait_on_sync_kiocb(iocb);
	if (rc >= 0) {
	lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
	lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
	touch_atime(lower_vfsmount, lower_dentry);
	}
	return rc;
	}

	struct ecryptfs_getdents_callback {
	void *dirent;
	struct dentry *dentry;
	filldir_t filldir;
	int filldir_called;
	int entries_written;
	};

	/* Inspired by generic filldir in fs/readdir.c */
	static int
	ecryptfs_filldir(void dirent, const char lower_name, int lower_namelen,
	loff_t offset, u64 ino, unsigned int d_type)
	{
	struct ecryptfs_getdents_callback *buf =
	(struct ecryptfs_getdents_callback *)dirent;
	size_t name_size;
	char *name;
	int rc;

	buf->filldir_called++;
	rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
	buf->dentry, lower_name,
	lower_namelen);
	if (rc) {
	printk(KERN_ERR "%s: Error attempting to decode and decrypt "
	"filename [%s]; rc = [%d]\n", __func__, lower_name,
	rc);
	goto out;
	}
	rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
	kfree(name);
	if (rc >= 0)
	buf->entries_written++;
	out:
	return rc;
	}

	/**
	* ecryptfs_readdir
	* @file: The eCryptfs directory file
	* @dirent: Directory entry handle
	* @filldir: The filldir callback function
	*/
	static int ecryptfs_readdir(struct file file, void dirent, filldir_t filldir)
	{
	int rc;
	struct file *lower_file;
	struct inode *inode;
	struct ecryptfs_getdents_callback buf;

	lower_file = ecryptfs_file_to_lower(file);
	lower_file->f_pos = file->f_pos;
	inode = file->f_path.dentry->d_inode;
	memset(&buf, 0, sizeof(buf));
	buf.dirent = dirent;
	buf.dentry = file->f_path.dentry;
	buf.filldir = filldir;
	buf.filldir_called = 0;
	buf.entries_written = 0;
	rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
	file->f_pos = lower_file->f_pos;
	if (rc < 0)
	goto out;
	if (buf.filldir_called && !buf.entries_written)
	goto out;
	if (rc >= 0)
	fsstack_copy_attr_atime(inode,
	lower_file->f_path.dentry->d_inode);
	out:
	return rc;
	}

	struct kmem_cache *ecryptfs_file_info_cache;

	/**
	* ecryptfs_open
	* @inode: inode speciying file to open
	* @file: Structure to return filled in
	*
	* Opens the file specified by inode.
	*
	* Returns zero on success; non-zero otherwise
	*/
	static int ecryptfs_open(struct inode inode, struct file file)
	{
	int rc = 0;
	struct ecryptfs_crypt_stat *crypt_stat = NULL;
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
	struct dentry *ecryptfs_dentry = file->f_path.dentry;
	/* Private value of ecryptfs_dentry allocated in
	* ecryptfs_lookup() */
	struct dentry *lower_dentry;
	struct ecryptfs_file_info *file_info;

	mount_crypt_stat = &ecryptfs_superblock_to_private(
	ecryptfs_dentry->d_sb)->mount_crypt_stat;
	if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
	&& ((file->f_flags & O_WRONLY) \|\| (file->f_flags & O_RDWR)
	\|\| (file->f_flags & O_CREAT) \|\| (file->f_flags & O_TRUNC)
	\|\| (file->f_flags & O_APPEND))) {
	printk(KERN_WARNING "Mount has encrypted view enabled; "
	"files may only be read\n");
	rc = -EPERM;
	goto out;
	}
	/* Released in ecryptfs_release or end of function if failure */
	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
	ecryptfs_set_file_private(file, file_info);
	if (!file_info) {
	ecryptfs_printk(KERN_ERR,
	"Error attempting to allocate memory\n");
	rc = -ENOMEM;
	goto out;
	}
	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
	mutex_lock(&crypt_stat->cs_mutex);
	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
	ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
	/* Policy code enabled in future release */
	crypt_stat->flags \|= (ECRYPTFS_POLICY_APPLIED
	\| ECRYPTFS_ENCRYPTED);
	}
	mutex_unlock(&crypt_stat->cs_mutex);
	if (!ecryptfs_inode_to_private(inode)->lower_file) {
	rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
	if (rc) {
	printk(KERN_ERR "%s: Error attempting to initialize "
	"the persistent file for the dentry with name "
	"[%s]; rc = [%d]\n", __func__,
	ecryptfs_dentry->d_name.name, rc);
	goto out;
	}
	}
	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
	&& !(file->f_flags & O_RDONLY)) {
	rc = -EPERM;
	printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
	"file must hence be opened RO\n", __func__);
	goto out;
	}
	ecryptfs_set_file_lower(
	file, ecryptfs_inode_to_private(inode)->lower_file);
	if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
	ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
	mutex_lock(&crypt_stat->cs_mutex);
	crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
	mutex_unlock(&crypt_stat->cs_mutex);
	rc = 0;
	goto out;
	}
	mutex_lock(&crypt_stat->cs_mutex);
	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
	\|\| !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
	rc = ecryptfs_read_metadata(ecryptfs_dentry);
	if (rc) {
	ecryptfs_printk(KERN_DEBUG,
	"Valid headers not found\n");
	if (!(mount_crypt_stat->flags
	& ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
	rc = -EIO;
	printk(KERN_WARNING "Either the lower file "
	"is not in a valid eCryptfs format, "
	"or the key could not be retrieved. "
	"Plaintext passthrough mode is not "
	"enabled; returning -EIO\n");
	mutex_unlock(&crypt_stat->cs_mutex);
	goto out_free;
	}
	rc = 0;
	crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
	mutex_unlock(&crypt_stat->cs_mutex);
	goto out;
	}
	}
	mutex_unlock(&crypt_stat->cs_mutex);
	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
	"size: [0x%.16x]\n", inode, inode->i_ino,
	i_size_read(inode));
	goto out;
	out_free:
	kmem_cache_free(ecryptfs_file_info_cache,
	ecryptfs_file_to_private(file));
	out:
	return rc;
	}

	static int ecryptfs_flush(struct file *file, fl_owner_t td)
	{
	int rc = 0;
	struct file *lower_file = NULL;

	lower_file = ecryptfs_file_to_lower(file);
	if (lower_file->f_op && lower_file->f_op->flush)
	rc = lower_file->f_op->flush(lower_file, td);
	return rc;
	}

	static int ecryptfs_release(struct inode inode, struct file file)
	{
	kmem_cache_free(ecryptfs_file_info_cache,
	ecryptfs_file_to_private(file));
	return 0;
	}

	static int
	ecryptfs_fsync(struct file file, struct dentry dentry, int datasync)
	{
	return vfs_fsync(ecryptfs_file_to_lower(file),
	ecryptfs_dentry_to_lower(dentry),
	datasync);
	}

	static int ecryptfs_fasync(int fd, struct file *file, int flag)
	{
	int rc = 0;
	struct file *lower_file = NULL;

	lock_kernel();
	lower_file = ecryptfs_file_to_lower(file);
	if (lower_file->f_op && lower_file->f_op->fasync)
	rc = lower_file->f_op->fasync(fd, lower_file, flag);
	unlock_kernel();
	return rc;
	}

	static int ecryptfs_ioctl(struct inode inode, struct file file,
	unsigned int cmd, unsigned long arg);

	const struct file_operations ecryptfs_dir_fops = {
	.readdir = ecryptfs_readdir,
	.ioctl = ecryptfs_ioctl,
	.open = ecryptfs_open,
	.flush = ecryptfs_flush,
	.release = ecryptfs_release,
	.fsync = ecryptfs_fsync,
	.fasync = ecryptfs_fasync,
	.splice_read = generic_file_splice_read,
	};

	const struct file_operations ecryptfs_main_fops = {
	.llseek = generic_file_llseek,
	.read = do_sync_read,
	.aio_read = ecryptfs_read_update_atime,
	.write = do_sync_write,
	.aio_write = generic_file_aio_write,
	.readdir = ecryptfs_readdir,
	.ioctl = ecryptfs_ioctl,
	.mmap = generic_file_mmap,
	.open = ecryptfs_open,
	.flush = ecryptfs_flush,
	.release = ecryptfs_release,
	.fsync = ecryptfs_fsync,
	.fasync = ecryptfs_fasync,
	.splice_read = generic_file_splice_read,
	};

	static int
	ecryptfs_ioctl(struct inode inode, struct file file, unsigned int cmd,
	unsigned long arg)
	{
	int rc = 0;
	struct file *lower_file = NULL;

	if (ecryptfs_file_to_private(file))
	lower_file = ecryptfs_file_to_lower(file);
	if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
	rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
	lower_file, cmd, arg);
	else
	rc = -ENOTTY;
	return rc;
	}