1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Common helpers for stackable filesystems and backing files.
4 *
5 * Copyright (C) 2023 CTERA Networks.
6 */
7
8#ifndef _LINUX_BACKING_FILE_H
9#define _LINUX_BACKING_FILE_H
10
11#include <linux/file.h>
12#include <linux/uio.h>
13#include <linux/fs.h>
14
15struct backing_file_ctx {
16 const struct cred *cred;
17 struct file *user_file;
18 void (*accessed)(struct file *);
19 void (*end_write)(struct file *);
20};
21
22struct file *backing_file_open(const struct path *user_path, int flags,
23 const struct path *real_path,
24 const struct cred *cred);
25ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
26 struct kiocb *iocb, int flags,
27 struct backing_file_ctx *ctx);
28ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
29 struct kiocb *iocb, int flags,
30 struct backing_file_ctx *ctx);
31ssize_t backing_file_splice_read(struct file *in, loff_t *ppos,
32 struct pipe_inode_info *pipe, size_t len,
33 unsigned int flags,
34 struct backing_file_ctx *ctx);
35ssize_t backing_file_splice_write(struct pipe_inode_info *pipe,
36 struct file *out, loff_t *ppos, size_t len,
37 unsigned int flags,
38 struct backing_file_ctx *ctx);
39int backing_file_mmap(struct file *file, struct vm_area_struct *vma,
40 struct backing_file_ctx *ctx);
41
42#endif /* _LINUX_BACKING_FILE_H */
43

source code of linux/include/linux/backing-file.h