/**
 * debugfs_remove_recursive - recursively removes a directory
 * @dentry: a pointer to a the dentry of the directory to be removed.
 *
 * This function recursively removes a directory tree in debugfs that
 * was previously created with a call to another debugfs function
 * (like debugfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed, no automatic cleanup of files will happen when a module is
 * removed, you are responsible here.
 */
void debugfs_remove_recursive(struct dentry *dentry)
{
	struct dentry *child;
	struct dentry *parent;

	if (!dentry)
		return;

	parent = dentry->d_parent;
	if (!parent || !parent->d_inode)
		return;

	parent = dentry;
	mutex_lock(&parent->d_inode->i_mutex);

	while (1) {
		/*
		 * When all dentries under "parent" has been removed,
		 * walk up the tree until we reach our starting point.
		 */
		if (list_empty(&parent->d_subdirs)) {
			mutex_unlock(&parent->d_inode->i_mutex);
			if (parent == dentry)
				break;
			parent = parent->d_parent;
			mutex_lock(&parent->d_inode->i_mutex);
		}
		child = list_entry(parent->d_subdirs.next, struct dentry,
				d_u.d_child);

		/*
		 * If "child" isn't empty, walk down the tree and
		 * remove all its descendants first.
		 */
		if (!list_empty(&child->d_subdirs)) {
			mutex_unlock(&parent->d_inode->i_mutex);
			parent = child;
			mutex_lock(&parent->d_inode->i_mutex);
			continue;
		}
		__debugfs_remove(child, parent);
		if (parent->d_subdirs.next == &child->d_u.d_child) {
			/*
			 * Avoid infinite loop if we fail to remove
			 * one dentry.
			 */
			mutex_unlock(&parent->d_inode->i_mutex);
			break;
		}
		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
	}

	parent = dentry->d_parent;
	mutex_lock(&parent->d_inode->i_mutex);
	__debugfs_remove(dentry, parent);
	mutex_unlock(&parent->d_inode->i_mutex);
	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}

static void drm_fs_inode_free(struct inode *inode)
{
	if (inode) {
		iput(inode);
		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
	}
}

static void __exit myfs_exit(void)
{
	myfs_registered = false;

	simple_release_fs(&myfs_mount, &myfs_mount_count);
	unregister_filesystem(&my_fs_type);
}

/**
 * debugfs_create_file - create a file in the debugfs filesystem
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this paramater is NULL, then the
 *          file will be created in the root of the debugfs filesystem.
 * @data: a pointer to something that the caller will want to get to later
 *        on.  The inode.i_private pointer will point to this value on
 *        the open() call.
 * @fops: a pointer to a struct file_operations that should be used for
 *        this file.
 *
 * This is the basic "create a file" function for debugfs.  It allows for a
 * wide range of flexibility in createing a file, or a directory (if you
 * want to create a directory, the debugfs_create_dir() function is
 * recommended to be used instead.)
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the debugfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, %NULL will be returned.
 *
 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
 * returned.
 */
struct dentry *debugfs_create_file(const char *name, mode_t mode,
				   struct dentry *parent, void *data,
				   const struct file_operations *fops)
{
	struct dentry *dentry = NULL;
	int error;

	pr_debug("debugfs: creating file '%s'\n",name);

	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
			      &debugfs_mount_count);
	if (error)
		goto exit;

	error = debugfs_create_by_name(name, mode, parent, &dentry);
	if (error) {
		dentry = NULL;
		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
		goto exit;
	}

	if (dentry->d_inode) {
		if (data)
			dentry->d_inode->i_private = data;
		if (fops)
			dentry->d_inode->i_fop = fops;
	}
exit:
	return dentry;
}

/**
 * debugfs_remove - removes a file or directory from the debugfs filesystem
 * @dentry: a pointer to a the dentry of the file or directory to be
 *          removed.
 *
 * This function removes a file or directory in debugfs that was previously
 * created with a call to another debugfs function (like
 * debugfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed, no automatic cleanup of files will happen when a module is
 * removed, you are responsible here.
 */
void debugfs_remove(struct dentry *dentry)
{
	struct dentry *parent;
	int ret = 0;
	
	if (!dentry)
		return;

	parent = dentry->d_parent;
	if (!parent || !parent->d_inode)
		return;

	mutex_lock(&parent->d_inode->i_mutex);
	if (debugfs_positive(dentry)) {
		if (dentry->d_inode) {
			dget(dentry);
			switch (dentry->d_inode->i_mode & S_IFMT) {
			case S_IFDIR:
				ret = simple_rmdir(parent->d_inode, dentry);
				break;
			case S_IFLNK:
				kfree(dentry->d_inode->i_private);
				/* fall through */
			default:
				simple_unlink(parent->d_inode, dentry);
				break;
			}
			if (!ret)
				d_delete(dentry);
			dput(dentry);
		}
	}
	mutex_unlock(&parent->d_inode->i_mutex);
	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}

/**
 * securityfs_create_file - create a file in the securityfs filesystem
 *
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this paramater is NULL, then the
 *          file will be created in the root of the securityfs filesystem.
 * @data: a pointer to something that the caller will want to get to later
 *        on.  The inode.u.generic_ip pointer will point to this value on
 *        the open() call.
 * @fops: a pointer to a struct file_operations that should be used for
 *        this file.
 *
 * This is the basic "create a file" function for securityfs.  It allows for a
 * wide range of flexibility in createing a file, or a directory (if you
 * want to create a directory, the securityfs_create_dir() function is
 * recommended to be used instead.)
 *
 * This function will return a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the securityfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here.)  If an error occurs, NULL will be returned.
 *
 * If securityfs is not enabled in the kernel, the value -ENODEV will be
 * returned.  It is not wise to check for this value, but rather, check for
 * NULL or !NULL instead as to eliminate the need for #ifdef in the calling
 * code.
 */
struct dentry *securityfs_create_file(const char *name, mode_t mode,
				   struct dentry *parent, void *data,
				   struct file_operations *fops)
{
	struct dentry *dentry = NULL;
	int error;

	pr_debug("securityfs: creating file '%s'\n",name);

	error = simple_pin_fs("securityfs", &mount, &mount_count);
	if (error) {
		dentry = ERR_PTR(error);
		goto exit;
	}

	error = create_by_name(name, mode, parent, &dentry);
	if (error) {
		dentry = ERR_PTR(error);
		simple_release_fs(&mount, &mount_count);
		goto exit;
	}

	if (dentry->d_inode) {
		if (fops)
			dentry->d_inode->i_fop = fops;
		if (data)
			dentry->d_inode->u.generic_ip = data;
	}
exit:
	return dentry;
}

static void __exit debugfs_exit(void)
{
	debugfs_registered = false;

	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
	unregister_filesystem(&debug_fs_type);
	kobject_put(debug_kobj);
}

struct dentry *__create_file(const char *name, umode_t mode,
				   struct dentry *parent, void *data,
				   const struct file_operations *fops)
{
	struct dentry *dentry = NULL;
	int error;

	pr_debug("debugfs: creating file '%s'\n",name);

	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
			      &debugfs_mount_count);
	if (error)
		goto exit;

	/* If the parent is not specified, we create it in the root.
	 * We need the root dentry to do this, which is in the super 
	 * block. A pointer to that is in the struct vfsmount that we
	 * have around.
	 */
	if (!parent)
		parent = debugfs_mount->mnt_root;

	dentry = NULL;
	mutex_lock(&parent->d_inode->i_mutex);
	dentry = lookup_one_len(name, parent, strlen(name));
	if (!IS_ERR(dentry)) {
		switch (mode & S_IFMT) {
		case S_IFDIR:
			error = debugfs_mkdir(parent->d_inode, dentry, mode);
					      
			break;
		case S_IFLNK:
			error = debugfs_link(parent->d_inode, dentry, mode,
					     data);
			break;
		default:
			error = debugfs_create(parent->d_inode, dentry, mode,
					       data, fops);
			break;
		}
		dput(dentry);
	} else
		error = PTR_ERR(dentry);
	mutex_unlock(&parent->d_inode->i_mutex);

	if (error) {
		dentry = NULL;
		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
	}
exit:
	return dentry;
}

struct dentry *capifs_new_ncci(unsigned int number, dev_t device)
{
	struct dentry *dentry;

	if (simple_pin_fs(&capifs_fs_type, &capifs_mnt, &capifs_mnt_count) < 0)
		return NULL;

	dentry = new_ncci(number, device);
	if (!dentry)
		simple_release_fs(&capifs_mnt, &capifs_mnt_count);

	return dentry;
}

/**
 * debugfs_remove - removes a file or directory from the debugfs filesystem
 * @dentry: a pointer to a the dentry of the file or directory to be
 *          removed.
 *
 * This function removes a file or directory in debugfs that was previously
 * created with a call to another debugfs function (like
 * debugfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed, no automatic cleanup of files will happen when a module is
 * removed, you are responsible here.
 */
void debugfs_remove(struct dentry *dentry)
{
	struct dentry *parent;
	
	if (!dentry)
		return;

	parent = dentry->d_parent;
	if (!parent || !parent->d_inode)
		return;

	mutex_lock(&parent->d_inode->i_mutex);
	__debugfs_remove(dentry, parent);
	mutex_unlock(&parent->d_inode->i_mutex);
	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}

static struct inode *drm_fs_inode_new(void)
{
	struct inode *inode;
	int r;

	r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
	if (r < 0) {
		DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
		return ERR_PTR(r);
	}

	inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
	if (IS_ERR(inode))
		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);

	return inode;
}

/**
 * debugfs_remove - removes a file or directory from the debugfs filesystem
 * @dentry: a pointer to a the dentry of the file or directory to be
 *          removed.
 *
 * This function removes a file or directory in debugfs that was previously
 * created with a call to another debugfs function (like
 * debugfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed, no automatic cleanup of files will happen when a module is
 * removed, you are responsible here.
 */
void debugfs_remove(struct dentry *dentry)
{
	struct dentry *parent;
	int ret;

	if (IS_ERR_OR_NULL(dentry))
		return;

	parent = dentry->d_parent;
	if (!parent || !parent->d_inode)
		return;

	mutex_lock(&parent->d_inode->i_mutex);
	ret = __debugfs_remove(dentry, parent);
	mutex_unlock(&parent->d_inode->i_mutex);
	if (!ret)
		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}

/**
 * securityfs_remove - removes a file or directory from the securityfs filesystem
 *
 * @dentry: a pointer to a the dentry of the file or directory to be removed.
 *
 * This function removes a file or directory in securityfs that was previously
 * created with a call to another securityfs function (like
 * securityfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed. No automatic cleanup of files will happen when a module is
 * removed; you are responsible here.
 */
void securityfs_remove(struct dentry *dentry)
{
	struct inode *dir;

	if (!dentry || IS_ERR(dentry))
		return;

	dir = d_inode(dentry->d_parent);
	inode_lock(dir);
	if (simple_positive(dentry)) {
		if (d_is_dir(dentry))
			simple_rmdir(dir, dentry);
		else
			simple_unlink(dir, dentry);
		dput(dentry);
	}
	inode_unlock(dir);
	simple_release_fs(&mount, &mount_count);
}

static struct file *cxl_getfile(const char *name,
				const struct file_operations *fops,
				void *priv, int flags)
{
	struct file *file;
	struct inode *inode;
	int rc;

	/* strongly inspired by anon_inode_getfile() */

	if (fops->owner && !try_module_get(fops->owner))
		return ERR_PTR(-ENOENT);

	rc = simple_pin_fs(&cxl_fs_type, &cxl_vfs_mount, &cxl_fs_cnt);
	if (rc < 0) {
		pr_err("Cannot mount cxl pseudo filesystem: %d\n", rc);
		file = ERR_PTR(rc);
		goto err_module;
	}

	inode = alloc_anon_inode(cxl_vfs_mount->mnt_sb);
	if (IS_ERR(inode)) {
		file = ERR_CAST(inode);
		goto err_fs;
	}

	file = alloc_file_pseudo(inode, cxl_vfs_mount, name,
				 flags & (O_ACCMODE | O_NONBLOCK), fops);
	if (IS_ERR(file))
		goto err_inode;

	file->private_data = priv;

	return file;

err_inode:
	iput(inode);
err_fs:
	simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
err_module:
	module_put(fops->owner);
	return file;
}

/**
 * securityfs_remove - removes a file or directory from the securityfs filesystem
 *
 * @dentry: a pointer to a the dentry of the file or directory to be removed.
 *
 * This function removes a file or directory in securityfs that was previously
 * created with a call to another securityfs function (like
 * securityfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed. No automatic cleanup of files will happen when a module is
 * removed; you are responsible here.
 */
void securityfs_remove(struct dentry *dentry)
{
	struct dentry *parent;

	if (!dentry || IS_ERR(dentry))
		return;

	parent = dentry->d_parent;
	if (!parent || d_really_is_negative(parent))
		return;

	inode_lock(d_inode(parent));
	if (simple_positive(dentry)) {
		if (d_is_dir(dentry))
			simple_rmdir(d_inode(parent), dentry);
		else
			simple_unlink(d_inode(parent), dentry);
		dput(dentry);
	}
	inode_unlock(d_inode(parent));
	simple_release_fs(&mount, &mount_count);
}

void capifs_free_ncci(struct dentry *dentry)
{
	struct dentry *root = capifs_mnt->mnt_sb->s_root;
	struct inode *inode;

	if (!dentry)
		return;

	mutex_lock(&root->d_inode->i_mutex);

	inode = dentry->d_inode;
	if (inode) {
		drop_nlink(inode);
		d_delete(dentry);
		dput(dentry);
	}
	dput(dentry);

	mutex_unlock(&root->d_inode->i_mutex);

	simple_release_fs(&capifs_mnt, &capifs_mnt_count);
}

/**
 * securityfs_remove - removes a file or directory from the securityfs filesystem
 *
 * @dentry: a pointer to a the dentry of the file or directory to be removed.
 *
 * This function removes a file or directory in securityfs that was previously
 * created with a call to another securityfs function (like
 * securityfs_create_file() or variants thereof.)
 *
 * This function is required to be called in order for the file to be
 * removed. No automatic cleanup of files will happen when a module is
 * removed; you are responsible here.
 */
void securityfs_remove(struct dentry *dentry)
{
	struct dentry *parent;

	if (!dentry || IS_ERR(dentry))
		return;

	parent = dentry->d_parent;
	if (!parent || !parent->d_inode)
		return;

	mutex_lock(&parent->d_inode->i_mutex);
	if (positive(dentry)) {
		if (dentry->d_inode) {
			if (S_ISDIR(dentry->d_inode->i_mode))
				simple_rmdir(parent->d_inode, dentry);
			else
				simple_unlink(parent->d_inode, dentry);
			dput(dentry);
		}
	}
	mutex_unlock(&parent->d_inode->i_mutex);
	simple_release_fs(&mount, &mount_count);
}

/**
 * securityfs_create_file - create a file in the securityfs filesystem
 *
 * @name: a pointer to a string containing the name of the file to create.
 * @mode: the permission that the file should have
 * @parent: a pointer to the parent dentry for this file.  This should be a
 *          directory dentry if set.  If this parameter is %NULL, then the
 *          file will be created in the root of the securityfs filesystem.
 * @data: a pointer to something that the caller will want to get to later
 *        on.  The inode.i_private pointer will point to this value on
 *        the open() call.
 * @fops: a pointer to a struct file_operations that should be used for
 *        this file.
 *
 * This is the basic "create a file" function for securityfs.  It allows for a
 * wide range of flexibility in creating a file, or a directory (if you
 * want to create a directory, the securityfs_create_dir() function is
 * recommended to be used instead).
 *
 * This function returns a pointer to a dentry if it succeeds.  This
 * pointer must be passed to the securityfs_remove() function when the file is
 * to be removed (no automatic cleanup happens if your module is unloaded,
 * you are responsible here).  If an error occurs, the function will return
 * the erorr value (via ERR_PTR).
 *
 * If securityfs is not enabled in the kernel, the value %-ENODEV is
 * returned.
 */
struct dentry *securityfs_create_file(const char *name, umode_t mode,
				   struct dentry *parent, void *data,
				   const struct file_operations *fops)
{
	struct dentry *dentry;
	int is_dir = S_ISDIR(mode);
	struct inode *dir, *inode;
	int error;

	if (!is_dir) {
		BUG_ON(!fops);
		mode = (mode & S_IALLUGO) | S_IFREG;
	}

	pr_debug("securityfs: creating file '%s'\n",name);

	error = simple_pin_fs(&fs_type, &mount, &mount_count);
	if (error)
		return ERR_PTR(error);

	if (!parent)
		parent = mount->mnt_root;

	dir = parent->d_inode;

	mutex_lock(&dir->i_mutex);
	dentry = lookup_one_len(name, parent, strlen(name));
	if (IS_ERR(dentry))
		goto out;

	if (dentry->d_inode) {
		error = -EEXIST;
		goto out1;
	}

	inode = new_inode(dir->i_sb);
	if (!inode) {
		error = -ENOMEM;
		goto out1;
	}

	inode->i_ino = get_next_ino();
	inode->i_mode = mode;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
	inode->i_private = data;
	if (is_dir) {
		inode->i_op = &simple_dir_inode_operations;
		inode->i_fop = &simple_dir_operations;
		inc_nlink(inode);
		inc_nlink(dir);
	} else {
		inode->i_fop = fops;
	}
	d_instantiate(dentry, inode);
	dget(dentry);
	mutex_unlock(&dir->i_mutex);
	return dentry;

out1:
	dput(dentry);
	dentry = ERR_PTR(error);
out:
	mutex_unlock(&dir->i_mutex);
	simple_release_fs(&mount, &mount_count);
	return dentry;
}

void cxl_release_mapping(struct cxl_context *ctx)
{
	if (ctx->kernelapi && ctx->mapping)
		simple_release_fs(&cxl_vfs_mount, &cxl_fs_cnt);
}

static void __exit aufs_exit(void)
{
	simple_release_fs(&aufs_mount,&aufs_mount_count);
	unregister_filesystem(&au_fs_type);
}