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 
15 struct backing_file_ctx {
16 	const struct cred *cred;
17 	void (*accessed)(struct file *file);
18 	void (*end_write)(struct kiocb *iocb, ssize_t);
19 };
20 
21 struct file *backing_file_open(const struct path *user_path, int flags,
22 			       const struct path *real_path,
23 			       const struct cred *cred);
24 struct file *backing_tmpfile_open(const struct path *user_path, int flags,
25 				  const struct path *real_parentpath,
26 				  umode_t mode, const struct cred *cred);
27 ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter,
28 			       struct kiocb *iocb, int flags,
29 			       struct backing_file_ctx *ctx);
30 ssize_t backing_file_write_iter(struct file *file, struct iov_iter *iter,
31 				struct kiocb *iocb, int flags,
32 				struct backing_file_ctx *ctx);
33 ssize_t backing_file_splice_read(struct file *in, struct kiocb *iocb,
34 				 struct pipe_inode_info *pipe, size_t len,
35 				 unsigned int flags,
36 				 struct backing_file_ctx *ctx);
37 ssize_t backing_file_splice_write(struct pipe_inode_info *pipe,
38 				  struct file *out, struct kiocb *iocb,
39 				  size_t len, unsigned int flags,
40 				  struct backing_file_ctx *ctx);
41 int backing_file_mmap(struct file *file, struct vm_area_struct *vma,
42 		      struct backing_file_ctx *ctx);
43 
44 #endif /* _LINUX_BACKING_FILE_H */
45