/**
 * 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)
{
	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 = 1;

	if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
		goto out;
	dentry_save = nd->dentry;
	vfsmount_save = nd->mnt;
	nd->dentry = lower_dentry;
	nd->mnt = lower_mnt;
	rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
	nd->dentry = dentry_save;
	nd->mnt = vfsmount_save;
	if (dentry->d_inode) {
		struct inode *lower_inode =
			ecryptfs_inode_to_lower(dentry->d_inode);

		fsstack_copy_attr_all(dentry->d_inode, lower_inode, NULL);
	}
out:
	return rc;
}

static int ecryptfs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
{
	struct dentry *lower_dentry;
	struct vfsmount *lower_mnt;
	struct dentry *dentry_save = NULL;
	struct vfsmount *vfsmount_save = NULL;
	int rc = 1;

	if (nd && nd->flags & LOOKUP_RCU)
		return -ECHILD;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
	if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
		goto out;
	if (nd) {
		dentry_save = nd->path.dentry;
		vfsmount_save = nd->path.mnt;
		nd->path.dentry = lower_dentry;
		nd->path.mnt = lower_mnt;
	}
	rc = lower_dentry->d_op->d_revalidate(lower_dentry, nd);
	if (nd) {
		nd->path.dentry = dentry_save;
		nd->path.mnt = vfsmount_save;
	}
	if (dentry->d_inode) {
		struct inode *lower_inode =
			ecryptfs_inode_to_lower(dentry->d_inode);

		fsstack_copy_attr_all(dentry->d_inode, lower_inode);
	}
out:
	return rc;
}

/**
 * ecryptfs_do_create2
 * @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 the new eCryptfs inode on success; an ERR_PTR on error condition
 */
static struct inode *
ecryptfs_do_create2(struct inode *directory_inode,
		   struct dentry *ecryptfs_dentry, umode_t mode, struct nameidata *nd)
{
	int rc;
	struct dentry *lower_dentry;
	struct dentry *lower_dir_dentry;
	struct vfsmount *lower_mnt = NULL;
	struct inode *inode = NULL;

	struct dentry *dentry_save = NULL;
	struct vfsmount *vfsmount_save = NULL;

	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
	if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
		goto out;

	lower_dir_dentry = lock_parent(lower_dentry);
	if (IS_ERR(lower_dir_dentry)) {
		ecryptfs_printk(KERN_ERR, "Error locking directory of "
				"dentry\n");
		inode = ERR_CAST(lower_dir_dentry);
		goto out;
	}
	if (nd) {
		dentry_save = nd->path.dentry;
		vfsmount_save = nd->path.mnt;
		nd->path.dentry = lower_dentry;
		nd->path.mnt = lower_mnt;
	}
	rc = vfs_create(lower_dir_dentry->d_inode, lower_dentry, mode, nd);
	if (nd) {
		nd->path.dentry = dentry_save;
		nd->path.mnt = vfsmount_save;
	}
	if (rc) {
		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
		       "rc = [%d]\n", __func__, rc);
		inode = ERR_PTR(rc);
		goto out_lock;
	}
	inode = __ecryptfs_get_inode(lower_dentry->d_inode,
				     directory_inode->i_sb);
	if (IS_ERR(inode)) {
		vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
		goto out_lock;
	}
	fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
	fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
out_lock:
	unlock_dir(lower_dir_dentry);
out:
	return inode;
}

/**
 * ecryptfs_d_release
 * @dentry: The ecryptfs dentry
 *
 * Called when a dentry is really deallocated.
 */
static void ecryptfs_d_release(struct dentry *dentry)
{
	if (ecryptfs_dentry_to_private(dentry)) {
		if (ecryptfs_dentry_to_lower(dentry)) {
			dput(ecryptfs_dentry_to_lower(dentry));
			mntput(ecryptfs_dentry_to_lower_mnt(dentry));
		}
		kmem_cache_free(ecryptfs_dentry_info_cache,
				ecryptfs_dentry_to_private(dentry));
	}
	return;
}

/**
 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 */
static int ecryptfs_lookup_interpose(struct dentry *dentry,
				     struct dentry *lower_dentry,
				     struct inode *dir_inode)
{
	struct inode *inode, *lower_inode = lower_dentry->d_inode;
	struct ecryptfs_dentry_info *dentry_info;
	struct vfsmount *lower_mnt;
	int rc = 0;

	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
	fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
	BUG_ON(!lower_dentry->d_count);

	dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
	ecryptfs_set_dentry_private(dentry, dentry_info);
	if (!dentry_info) {
		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to allocate ecryptfs_dentry_info struct\n",
			__func__);
		dput(lower_dentry);
		mntput(lower_mnt);
		d_drop(dentry);
		return -ENOMEM;
	}
	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);
		return 0;
	}
	inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
	if (IS_ERR(inode)) {
		printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
		       __func__, PTR_ERR(inode));
		return PTR_ERR(inode);
	}
	if (S_ISREG(inode->i_mode)) {
		rc = ecryptfs_i_size_read(dentry, inode);
		if (rc) {
			make_bad_inode(inode);
			return rc;
		}
	}

	if (inode->i_state & I_NEW)
		unlock_new_inode(inode);
	d_add(dentry, inode);

	return rc;
}

/**
 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 */
static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
				     struct dentry *lower_dentry)
{
	struct inode *inode, *lower_inode = d_inode(lower_dentry);
	struct ecryptfs_dentry_info *dentry_info;
	struct vfsmount *lower_mnt;
	int rc = 0;

	dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
	if (!dentry_info) {
		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to allocate ecryptfs_dentry_info struct\n",
			__func__);
		dput(lower_dentry);
		return ERR_PTR(-ENOMEM);
	}

	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
	fsstack_copy_attr_atime(d_inode(dentry->d_parent),
				d_inode(lower_dentry->d_parent));
	BUG_ON(!d_count(lower_dentry));

	ecryptfs_set_dentry_private(dentry, dentry_info);
	dentry_info->lower_path.mnt = lower_mnt;
	dentry_info->lower_path.dentry = lower_dentry;

	if (d_really_is_negative(lower_dentry)) {
		/* We want to add because we couldn't find in lower */
		d_add(dentry, NULL);
		return NULL;
	}
	inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
	if (IS_ERR(inode)) {
		printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
		       __func__, PTR_ERR(inode));
		return ERR_CAST(inode);
	}
	if (S_ISREG(inode->i_mode)) {
		rc = ecryptfs_i_size_read(dentry, inode);
		if (rc) {
			make_bad_inode(inode);
			return ERR_PTR(rc);
		}
	}

	if (inode->i_state & I_NEW)
		unlock_new_inode(inode);
	return d_splice_alias(inode, dentry);
}

/**
 * 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) {
		struct vfsmount *lower_mnt =
			ecryptfs_dentry_to_lower_mnt(dentry);

		mntput(lower_mnt);
		dput(lower_dentry);
	}
	return;
}

/**
 * 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)
{
	ssize_t 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;
}

/**
 * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
 * @dentry: The ecryptfs dentry
 * @flags: lookup flags
 *
 * 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, unsigned int flags)
{
	struct dentry *lower_dentry;
	struct vfsmount *lower_mnt;
	int rc = 1;

	if (flags & LOOKUP_RCU)
		return -ECHILD;

	lower_dentry = ecryptfs_dentry_to_lower(dentry);
	lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
	if (!lower_dentry->d_op || !lower_dentry->d_op->d_revalidate)
		goto out;
	rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
	if (dentry->d_inode) {
		struct inode *lower_inode =
			ecryptfs_inode_to_lower(dentry->d_inode);

		fsstack_copy_attr_all(dentry->d_inode, lower_inode);
	}
out:
	return rc;
}

/**
 * ecryptfs_show_options
 *
 * Prints the directory we are currently mounted over.
 * Returns zero on success; non-zero otherwise
 */
static int ecryptfs_show_options(struct seq_file *m, struct vfsmount *mnt)
{
	struct super_block *sb = mnt->mnt_sb;
	struct dentry *lower_root_dentry = ecryptfs_dentry_to_lower(sb->s_root);
	struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(sb->s_root);
	char *tmp_page;
	char *path;
	int rc = 0;

	tmp_page = (char *)__get_free_page(GFP_KERNEL);
	if (!tmp_page) {
		rc = -ENOMEM;
		goto out;
	}
	path = d_path(lower_root_dentry, lower_mnt, tmp_page, PAGE_SIZE);
	if (IS_ERR(path)) {
		rc = PTR_ERR(path);
		goto out;
	}
	seq_printf(m, ",dir=%s", path);
	free_page((unsigned long)tmp_page);
out:
	return rc;
}

/**
 * ecryptfs_lookup_interpose - Dentry interposition for a lookup
 */
static int ecryptfs_lookup_interpose(struct dentry *dentry,
				     struct dentry *lower_dentry,
				     struct inode *dir_inode)
{
	struct inode *inode, *lower_inode = lower_dentry->d_inode;
	struct ecryptfs_dentry_info *dentry_info;
	struct vfsmount *lower_mnt;
	int rc = 0;

	dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
	if (!dentry_info) {
		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to allocate ecryptfs_dentry_info struct\n",
			__func__);
		dput(lower_dentry);
		return -ENOMEM;
	}

	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
	fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
	BUG_ON(!lower_dentry->d_count);

	ecryptfs_set_dentry_private(dentry, dentry_info);
	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);
		return 0;
	}
	inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
	if (IS_ERR(inode)) {
		printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
		       __func__, PTR_ERR(inode));
		return PTR_ERR(inode);
	}
	if (S_ISREG(inode->i_mode)) {
		rc = ecryptfs_i_size_read(dentry, inode);
		if (rc) {
			make_bad_inode(inode);
			return rc;
		}
	}

#ifdef CONFIG_SDP
	if (S_ISDIR(inode->i_mode) && dentry) {
	    if(IS_UNDER_ROOT(dentry)) {
	        struct ecryptfs_mount_crypt_stat *mount_crypt_stat  =
	                &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
	        printk("Lookup a directoy under root directory of current partition.\n");

	        if(is_chamber_directory(mount_crypt_stat, (char *)dentry->d_name.name)) {
	            /*
	             * When this directory is under ROOT directory and the name is registered
	             * as Chamber.
	             */
	            printk("This is a chamber directory\n");
	            set_chamber_flag(inode);
	        }
	    } else if(IS_SENSITIVE_DENTRY(dentry->d_parent)) {
	        /*
	         * When parent directory is sensitive
	         */
	        struct ecryptfs_crypt_stat *crypt_stat =
	                &ecryptfs_inode_to_private(inode)->crypt_stat;

	        printk("Parent %s is sensitive. so this directory is sensitive too\n",
	                dentry->d_parent->d_name.name);
	        crypt_stat->flags |= ECRYPTFS_DEK_IS_SENSITIVE;
	    }
	}
#endif

	if (inode->i_state & I_NEW)
		unlock_new_inode(inode);
	d_add(dentry, inode);

	return rc;
}

/**
 * ecryptfs_lookup_and_interpose_lower - Perform a lookup
 */
int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
					struct dentry *lower_dentry,
					struct inode *ecryptfs_dir_inode)
{
	struct dentry *lower_dir_dentry;
	struct vfsmount *lower_mnt;
	struct inode *lower_inode;
	struct ecryptfs_crypt_stat *crypt_stat;
	char *page_virt = NULL;
	int put_lower = 0, rc = 0;

	lower_dir_dentry = lower_dentry->d_parent;
	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
				   ecryptfs_dentry->d_parent));
	lower_inode = lower_dentry->d_inode;
	fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
	BUG_ON(!lower_dentry->d_count);
	ecryptfs_set_dentry_private(ecryptfs_dentry,
				    kmem_cache_alloc(ecryptfs_dentry_info_cache,
						     GFP_KERNEL));
	if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
		rc = -ENOMEM;
		printk(KERN_ERR "%s: Out of memory whilst attempting "
		       "to allocate ecryptfs_dentry_info struct\n",
			__func__);
		goto out_put;
	}
	ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
	ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
	if (!lower_dentry->d_inode) {
		/* We want to add because we couldn't find in lower */
		d_add(ecryptfs_dentry, NULL);
		goto out;
	}
	rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
				ecryptfs_dir_inode->i_sb,
				ECRYPTFS_INTERPOSE_FLAG_D_ADD);
	if (rc) {
		printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
		       __func__, rc);
		goto out;
	}
	if (S_ISDIR(lower_inode->i_mode))
		goto out;
	if (S_ISLNK(lower_inode->i_mode))
		goto out;
	if (special_file(lower_inode->i_mode))
		goto out;
	/* Released in this function */
	page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
	if (!page_virt) {
		printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
		       __func__);
		rc = -ENOMEM;
		goto out;
	}
	rc = ecryptfs_get_lower_file(ecryptfs_dentry);
	if (rc) {
		printk(KERN_ERR "%s: Error attempting to initialize "
			"the lower file for the dentry with name "
			"[%s]; rc = [%d]\n", __func__,
			ecryptfs_dentry->d_name.name, rc);
		goto out_free_kmem;
	}
	put_lower = 1;
	crypt_stat = &ecryptfs_inode_to_private(
					ecryptfs_dentry->d_inode)->crypt_stat;
	/* TODO: lock for crypt_stat comparison */
	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
			ecryptfs_set_default_sizes(crypt_stat);
	rc = ecryptfs_read_and_validate_header_region(page_virt,
						      ecryptfs_dentry->d_inode);
	if (rc) {
		memset(page_virt, 0, PAGE_CACHE_SIZE);
		rc = ecryptfs_read_and_validate_xattr_region(page_virt,
							     ecryptfs_dentry);
		if (rc) {
			rc = 0;
			goto out_free_kmem;
		}
		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
	}
	ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
out_free_kmem:
	kmem_cache_free(ecryptfs_header_cache_2, page_virt);
	goto out;
out_put:
	dput(lower_dentry);
	mntput(lower_mnt);
	d_drop(ecryptfs_dentry);
out:
	if (put_lower)
		ecryptfs_put_lower_file(ecryptfs_dentry->d_inode);
	return rc;
}

/**
 * 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 = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	struct inode *lower_inode = NULL;
	struct file *lower_file = NULL;
	struct vfsmount *lower_mnt;
	struct ecryptfs_file_info *file_info;
	int lower_flags;

	/* Released in ecryptfs_release or end of function if failure */
	file_info = kmem_cache_alloc(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;
	}
	memset(file_info, 0, sizeof(*file_info));
	lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
	mount_crypt_stat = &ecryptfs_superblock_to_private(
		ecryptfs_dentry->d_sb)->mount_crypt_stat;
	mutex_lock(&crypt_stat->cs_mutex);
	if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED)) {
		ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
		/* Policy code enabled in future release */
		ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED);
		ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
	}
	mutex_unlock(&crypt_stat->cs_mutex);
	lower_flags = file->f_flags;
	if ((lower_flags & O_ACCMODE) == O_WRONLY)
		lower_flags = (lower_flags & O_ACCMODE) | O_RDWR;
	if (file->f_flags & O_APPEND)
		lower_flags &= ~O_APPEND;
	lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
	/* Corresponding fput() in ecryptfs_release() */
	if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
					   lower_flags))) {
		ecryptfs_printk(KERN_ERR, "Error opening lower file\n");
		goto out_puts;
	}
	ecryptfs_set_file_lower(file, lower_file);
	/* Isn't this check the same as the one in lookup? */
	lower_inode = lower_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);
		rc = 0;
		goto out;
	}
	mutex_lock(&crypt_stat->cs_mutex);
	if (i_size_read(lower_inode) < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
		if (!(mount_crypt_stat->flags
		      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
			rc = -EIO;
			printk(KERN_WARNING "Attempt to read file that is "
			       "not in a valid eCryptfs format, and plaintext "
			       "passthrough mode is not enabled; returning "
			       "-EIO\n");
			mutex_unlock(&crypt_stat->cs_mutex);
			goto out_puts;
		}
		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
		rc = 0;
		mutex_unlock(&crypt_stat->cs_mutex);
		goto out;
	} else if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
					ECRYPTFS_POLICY_APPLIED)
		   || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
					   ECRYPTFS_KEY_VALID)) {
		rc = ecryptfs_read_headers(ecryptfs_dentry, lower_file);
		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 "Attempt to read file that "
				       "is not in a valid eCryptfs format, "
				       "and plaintext passthrough mode is not "
				       "enabled; returning -EIO\n");
				mutex_unlock(&crypt_stat->cs_mutex);
				goto out_puts;
//.........这里部分代码省略.........

/**
 * 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;
	char *encoded_name;
	int encoded_namelen;
	struct ecryptfs_crypt_stat *crypt_stat = NULL;
	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
	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, ".."))) {
		d_drop(dentry);
		goto out;
	}
	encoded_namelen = ecryptfs_encode_filename(crypt_stat,
						   dentry->d_name.name,
						   dentry->d_name.len,
						   &encoded_name);
	if (encoded_namelen < 0) {
		rc = encoded_namelen;
		d_drop(dentry);
		goto out;
	}
	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);
	if (IS_ERR(lower_dentry)) {
		ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
		rc = PTR_ERR(lower_dentry);
		d_drop(dentry);
		goto out;
	}
	lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
	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;
	fsstack_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,
						     GFP_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,
				ECRYPTFS_INTERPOSE_FLAG_D_ADD);
	if (rc) {
		ecryptfs_printk(KERN_ERR, "Error interposing\n");
		goto out;
	}
	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 (special_file(lower_inode->i_mode)) {
		ecryptfs_printk(KERN_DEBUG, "Is a special file; 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;
	}
	/* Released in this function */
	page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
//.........这里部分代码省略.........