fs/ecryptfs/file.c - kernel/msm-4.19 - 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 "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,
 				struct iov_iter *to)
 {
 	ssize_t rc;
 	struct path *path;
 	struct file *file = iocb->ki_filp;

 	rc = generic_file_read_iter(iocb, to);
 	if (rc >= 0) {
 		path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
 		touch_atime(path);
 	}
 	return rc;
 }

 struct ecryptfs_getdents_callback {
 	struct dir_context ctx;
 	struct dir_context *caller;
 	struct super_block *sb;
 	int filldir_called;
 	int entries_written;
 };

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

 	buf->filldir_called++;
 	rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
 						  buf->sb, 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;
 	}
 	buf->caller->pos = buf->ctx.pos;
 	rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
 	kfree(name);
 	if (!rc)
 		buf->entries_written++;
 out:
 	return rc;
 }

 /**
  * ecryptfs_readdir
  * @file: The eCryptfs directory file
  * @ctx: The actor to feed the entries to
  */
 static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
 {
 	int rc;
 	struct file *lower_file;
 	struct inode *inode = file_inode(file);
 	struct ecryptfs_getdents_callback buf = {
 		.ctx.actor = ecryptfs_filldir,
 		.caller = ctx,
 		.sb = inode->i_sb,
 	};
 	lower_file = ecryptfs_file_to_lower(file);
 	rc = iterate_dir(lower_file, &buf.ctx);
 	ctx->pos = buf.ctx.pos;
 	if (rc < 0)
 		goto out;
 	if (buf.filldir_called && !buf.entries_written)
 		goto out;
 	if (rc >= 0)
 		fsstack_copy_attr_atime(inode,
 					file_inode(lower_file));
 out:
 	return rc;
 }

 struct kmem_cache *ecryptfs_file_info_cache;

 static int read_or_initialize_metadata(struct dentry *dentry)
 {
 	struct inode *inode = d_inode(dentry);
 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
 	struct ecryptfs_crypt_stat *crypt_stat;
 	int rc;

 	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
 	mount_crypt_stat = &ecryptfs_superblock_to_private(
 						inode->i_sb)->mount_crypt_stat;
 	mutex_lock(&crypt_stat->cs_mutex);

 	if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
 	    crypt_stat->flags & ECRYPTFS_KEY_VALID) {
 		rc = 0;
 		goto out;
 	}

 	rc = ecryptfs_read_metadata(dentry);
 	if (!rc)
 		goto out;

 	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
 		crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
 				       | ECRYPTFS_ENCRYPTED);
 		rc = 0;
 		goto out;
 	}

 	if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
 	    !i_size_read(ecryptfs_inode_to_lower(inode))) {
 		rc = ecryptfs_initialize_file(dentry, inode);
 		if (!rc)
 			goto out;
 	}

 	rc = -EIO;
 out:
 	mutex_unlock(&crypt_stat->cs_mutex);
 	return rc;
 }

 static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct file *lower_file = ecryptfs_file_to_lower(file);
 	/*
 	 * Don't allow mmap on top of file systems that don't support it
 	 * natively.  If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
 	 * allows recursive mounting, this will need to be extended.
 	 */
 	if (!lower_file->f_op->mmap)
 		return -ENODEV;
 	return generic_file_mmap(file, vma);
 }

 /**
  * ecryptfs_open
  * @inode: inode specifying 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 dentry *ecryptfs_dentry = file->f_path.dentry;
 	/* Private value of ecryptfs_dentry allocated in
 	 * ecryptfs_lookup() */
 	struct ecryptfs_file_info *file_info;

 	/* 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;
 	}
 	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);
 	rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
 	if (rc) {
 		printk(KERN_ERR "%s: Error attempting to initialize "
 			"the lower file for the dentry with name "
 			"[%pd]; rc = [%d]\n", __func__,
 			ecryptfs_dentry, rc);
 		goto out_free;
 	}
 	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
 	    == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
 		rc = -EPERM;
 		printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
 		       "file must hence be opened RO\n", __func__);
 		goto out_put;
 	}
 	ecryptfs_set_file_lower(
 		file, ecryptfs_inode_to_private(inode)->lower_file);
 	rc = read_or_initialize_metadata(ecryptfs_dentry);
 	if (rc)
 		goto out_put;
 	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
 			"[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
 			(unsigned long long)i_size_read(inode));
 	goto out;
 out_put:
 	ecryptfs_put_lower_file(inode);
 out_free:
 	kmem_cache_free(ecryptfs_file_info_cache,
 			ecryptfs_file_to_private(file));
 out:
 	return rc;
 }

 /**
  * ecryptfs_dir_open
  * @inode: inode specifying 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_dir_open(struct inode *inode, struct file *file)
 {
 	struct dentry *ecryptfs_dentry = file->f_path.dentry;
 	/* Private value of ecryptfs_dentry allocated in
 	 * ecryptfs_lookup() */
 	struct ecryptfs_file_info *file_info;
 	struct file *lower_file;

 	/* 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 (unlikely(!file_info)) {
 		ecryptfs_printk(KERN_ERR,
 				"Error attempting to allocate memory\n");
 		return -ENOMEM;
 	}
 	lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry),
 				 file->f_flags, current_cred());
 	if (IS_ERR(lower_file)) {
 		printk(KERN_ERR "%s: Error attempting to initialize "
 			"the lower file for the dentry with name "
 			"[%pd]; rc = [%ld]\n", __func__,
 			ecryptfs_dentry, PTR_ERR(lower_file));
 		kmem_cache_free(ecryptfs_file_info_cache, file_info);
 		return PTR_ERR(lower_file);
 	}
 	ecryptfs_set_file_lower(file, lower_file);
 	return 0;
 }

 static int ecryptfs_flush(struct file *file, fl_owner_t td)
 {
 	struct file *lower_file = ecryptfs_file_to_lower(file);

 	if (lower_file->f_op->flush) {
 		filemap_write_and_wait(file->f_mapping);
 		return lower_file->f_op->flush(lower_file, td);
 	}

 	return 0;
 }

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

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

 static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)
 {
 	return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);
 }

 static int
 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
 	int rc;

 	rc = file_write_and_wait(file);
 	if (rc)
 		return rc;

 	return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
 }

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

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

 static long
 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct file *lower_file = ecryptfs_file_to_lower(file);
 	long rc = -ENOTTY;

 	if (!lower_file->f_op->unlocked_ioctl)
 		return rc;

 	switch (cmd) {
 	case FITRIM:
 	case FS_IOC_GETFLAGS:
 	case FS_IOC_SETFLAGS:
 	case FS_IOC_GETVERSION:
 	case FS_IOC_SETVERSION:
 		rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
 		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));

 		return rc;
 	default:
 		return rc;
 	}
 }

 #ifdef CONFIG_COMPAT
 static long
 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct file *lower_file = ecryptfs_file_to_lower(file);
 	long rc = -ENOIOCTLCMD;

 	if (!lower_file->f_op->compat_ioctl)
 		return rc;

 	switch (cmd) {
 	case FS_IOC32_GETFLAGS:
 	case FS_IOC32_SETFLAGS:
 	case FS_IOC32_GETVERSION:
 	case FS_IOC32_SETVERSION:
 		rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
 		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));

 		return rc;
 	default:
 		return rc;
 	}
 }
 #endif

 const struct file_operations ecryptfs_dir_fops = {
 	.iterate_shared = ecryptfs_readdir,
 	.read = generic_read_dir,
 	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = ecryptfs_compat_ioctl,
 #endif
 	.open = ecryptfs_dir_open,
 	.release = ecryptfs_dir_release,
 	.fsync = ecryptfs_fsync,
 	.llseek = ecryptfs_dir_llseek,
 };

 const struct file_operations ecryptfs_main_fops = {
 	.llseek = generic_file_llseek,
 	.read_iter = ecryptfs_read_update_atime,
 	.write_iter = generic_file_write_iter,
 	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl = ecryptfs_compat_ioctl,
 #endif
 	.mmap = ecryptfs_mmap,
 	.open = ecryptfs_open,
 	.flush = ecryptfs_flush,
 	.release = ecryptfs_release,
 	.fsync = ecryptfs_fsync,
 	.fasync = ecryptfs_fasync,
 	.splice_read = generic_file_splice_read,
 };
	/**
	* 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 "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,
	struct iov_iter *to)
	{
	ssize_t rc;
	struct path *path;
	struct file *file = iocb->ki_filp;

	rc = generic_file_read_iter(iocb, to);
	if (rc >= 0) {
	path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
	touch_atime(path);
	}
	return rc;
	}

	struct ecryptfs_getdents_callback {
	struct dir_context ctx;
	struct dir_context *caller;
	struct super_block *sb;
	int filldir_called;
	int entries_written;
	};

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

	buf->filldir_called++;
	rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
	buf->sb, 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;
	}
	buf->caller->pos = buf->ctx.pos;
	rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
	kfree(name);
	if (!rc)
	buf->entries_written++;
	out:
	return rc;
	}

	/**
	* ecryptfs_readdir
	* @file: The eCryptfs directory file
	* @ctx: The actor to feed the entries to
	*/
	static int ecryptfs_readdir(struct file file, struct dir_context ctx)
	{
	int rc;
	struct file *lower_file;
	struct inode *inode = file_inode(file);
	struct ecryptfs_getdents_callback buf = {
	.ctx.actor = ecryptfs_filldir,
	.caller = ctx,
	.sb = inode->i_sb,
	};
	lower_file = ecryptfs_file_to_lower(file);
	rc = iterate_dir(lower_file, &buf.ctx);
	ctx->pos = buf.ctx.pos;
	if (rc < 0)
	goto out;
	if (buf.filldir_called && !buf.entries_written)
	goto out;
	if (rc >= 0)
	fsstack_copy_attr_atime(inode,
	file_inode(lower_file));
	out:
	return rc;
	}

	struct kmem_cache *ecryptfs_file_info_cache;

	static int read_or_initialize_metadata(struct dentry *dentry)
	{
	struct inode *inode = d_inode(dentry);
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
	struct ecryptfs_crypt_stat *crypt_stat;
	int rc;

	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
	mount_crypt_stat = &ecryptfs_superblock_to_private(
	inode->i_sb)->mount_crypt_stat;
	mutex_lock(&crypt_stat->cs_mutex);

	if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
	crypt_stat->flags & ECRYPTFS_KEY_VALID) {
	rc = 0;
	goto out;
	}

	rc = ecryptfs_read_metadata(dentry);
	if (!rc)
	goto out;

	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
	crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
	\| ECRYPTFS_ENCRYPTED);
	rc = 0;
	goto out;
	}

	if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
	!i_size_read(ecryptfs_inode_to_lower(inode))) {
	rc = ecryptfs_initialize_file(dentry, inode);
	if (!rc)
	goto out;
	}

	rc = -EIO;
	out:
	mutex_unlock(&crypt_stat->cs_mutex);
	return rc;
	}

	static int ecryptfs_mmap(struct file file, struct vm_area_struct vma)
	{
	struct file *lower_file = ecryptfs_file_to_lower(file);
	/*
	* Don't allow mmap on top of file systems that don't support it
	* natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
	* allows recursive mounting, this will need to be extended.
	*/
	if (!lower_file->f_op->mmap)
	return -ENODEV;
	return generic_file_mmap(file, vma);
	}

	/**
	* ecryptfs_open
	* @inode: inode specifying 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 dentry *ecryptfs_dentry = file->f_path.dentry;
	/* Private value of ecryptfs_dentry allocated in
	* ecryptfs_lookup() */
	struct ecryptfs_file_info *file_info;

	/* 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;
	}
	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);
	rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
	if (rc) {
	printk(KERN_ERR "%s: Error attempting to initialize "
	"the lower file for the dentry with name "
	"[%pd]; rc = [%d]\n", __func__,
	ecryptfs_dentry, rc);
	goto out_free;
	}
	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
	== O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
	rc = -EPERM;
	printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
	"file must hence be opened RO\n", __func__);
	goto out_put;
	}
	ecryptfs_set_file_lower(
	file, ecryptfs_inode_to_private(inode)->lower_file);
	rc = read_or_initialize_metadata(ecryptfs_dentry);
	if (rc)
	goto out_put;
	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
	"[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
	(unsigned long long)i_size_read(inode));
	goto out;
	out_put:
	ecryptfs_put_lower_file(inode);
	out_free:
	kmem_cache_free(ecryptfs_file_info_cache,
	ecryptfs_file_to_private(file));
	out:
	return rc;
	}

	/**
	* ecryptfs_dir_open
	* @inode: inode specifying 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_dir_open(struct inode inode, struct file file)
	{
	struct dentry *ecryptfs_dentry = file->f_path.dentry;
	/* Private value of ecryptfs_dentry allocated in
	* ecryptfs_lookup() */
	struct ecryptfs_file_info *file_info;
	struct file *lower_file;

	/* 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 (unlikely(!file_info)) {
	ecryptfs_printk(KERN_ERR,
	"Error attempting to allocate memory\n");
	return -ENOMEM;
	}
	lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry),
	file->f_flags, current_cred());
	if (IS_ERR(lower_file)) {
	printk(KERN_ERR "%s: Error attempting to initialize "
	"the lower file for the dentry with name "
	"[%pd]; rc = [%ld]\n", __func__,
	ecryptfs_dentry, PTR_ERR(lower_file));
	kmem_cache_free(ecryptfs_file_info_cache, file_info);
	return PTR_ERR(lower_file);
	}
	ecryptfs_set_file_lower(file, lower_file);
	return 0;
	}

	static int ecryptfs_flush(struct file *file, fl_owner_t td)
	{
	struct file *lower_file = ecryptfs_file_to_lower(file);

	if (lower_file->f_op->flush) {
	filemap_write_and_wait(file->f_mapping);
	return lower_file->f_op->flush(lower_file, td);
	}

	return 0;
	}

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

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

	static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)
	{
	return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);
	}

	static int
	ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
	{
	int rc;

	rc = file_write_and_wait(file);
	if (rc)
	return rc;

	return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
	}

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

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

	static long
	ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct file *lower_file = ecryptfs_file_to_lower(file);
	long rc = -ENOTTY;

	if (!lower_file->f_op->unlocked_ioctl)
	return rc;

	switch (cmd) {
	case FITRIM:
	case FS_IOC_GETFLAGS:
	case FS_IOC_SETFLAGS:
	case FS_IOC_GETVERSION:
	case FS_IOC_SETVERSION:
	rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
	fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));

	return rc;
	default:
	return rc;
	}
	}

	#ifdef CONFIG_COMPAT
	static long
	ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct file *lower_file = ecryptfs_file_to_lower(file);
	long rc = -ENOIOCTLCMD;

	if (!lower_file->f_op->compat_ioctl)
	return rc;

	switch (cmd) {
	case FS_IOC32_GETFLAGS:
	case FS_IOC32_SETFLAGS:
	case FS_IOC32_GETVERSION:
	case FS_IOC32_SETVERSION:
	rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
	fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));

	return rc;
	default:
	return rc;
	}
	}
	#endif

	const struct file_operations ecryptfs_dir_fops = {
	.iterate_shared = ecryptfs_readdir,
	.read = generic_read_dir,
	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
	#ifdef CONFIG_COMPAT
	.compat_ioctl = ecryptfs_compat_ioctl,
	#endif
	.open = ecryptfs_dir_open,
	.release = ecryptfs_dir_release,
	.fsync = ecryptfs_fsync,
	.llseek = ecryptfs_dir_llseek,
	};

	const struct file_operations ecryptfs_main_fops = {
	.llseek = generic_file_llseek,
	.read_iter = ecryptfs_read_update_atime,
	.write_iter = generic_file_write_iter,
	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
	#ifdef CONFIG_COMPAT
	.compat_ioctl = ecryptfs_compat_ioctl,
	#endif
	.mmap = ecryptfs_mmap,
	.open = ecryptfs_open,
	.flush = ecryptfs_flush,
	.release = ecryptfs_release,
	.fsync = ecryptfs_fsync,
	.fasync = ecryptfs_fasync,
	.splice_read = generic_file_splice_read,
	};