// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>
#include <linux/fsnotify.h>

#include <uapi/linux/io_uring.h>

#include "io_uring.h"
#include "sync.h"

struct io_sync {
	struct file			*file;
	loff_t				len;
	loff_t				off;
	int				flags;
	int				mode;
};

int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
	struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);

	if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in))
		return -EINVAL;

	sync->off = READ_ONCE(sqe->off);
	sync->len = READ_ONCE(sqe->len);
	sync->flags = READ_ONCE(sqe->sync_range_flags);
	return 0;
}

int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags)
{
	struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
	int ret;

	/* sync_file_range always requires a blocking context */
	if (issue_flags & IO_URING_F_NONBLOCK)
		return -EAGAIN;

	ret = sync_file_range(req->file, sync->off, sync->len, sync->flags);
	io_req_set_res(req, ret, 0);
	return IOU_OK;
}

int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
	struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);

	if (unlikely(sqe->addr || sqe->buf_index || sqe->splice_fd_in))
		return -EINVAL;

	sync->flags = READ_ONCE(sqe->fsync_flags);
	if (unlikely(sync->flags & ~IORING_FSYNC_DATASYNC))
		return -EINVAL;

	sync->off = READ_ONCE(sqe->off);
	sync->len = READ_ONCE(sqe->len);
	return 0;
}

int io_fsync(struct io_kiocb *req, unsigned int issue_flags)
{
	struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
	loff_t end = sync->off + sync->len;
	int ret;

	/* fsync always requires a blocking context */
	if (issue_flags & IO_URING_F_NONBLOCK)
		return -EAGAIN;

	ret = vfs_fsync_range(req->file, sync->off, end > 0 ? end : LLONG_MAX,
				sync->flags & IORING_FSYNC_DATASYNC);
	io_req_set_res(req, ret, 0);
	return IOU_OK;
}

int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
	struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);

	if (sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in)
		return -EINVAL;

	sync->off = READ_ONCE(sqe->off);
	sync->len = READ_ONCE(sqe->addr);
	sync->mode = READ_ONCE(sqe->len);
	return 0;
}

int io_fallocate(struct io_kiocb *req, unsigned int issue_flags)
{
	struct io_sync *sync = io_kiocb_to_cmd(req, struct io_sync);
	int ret;

	/* fallocate always requiring blocking context */
	if (issue_flags & IO_URING_F_NONBLOCK)
		return -EAGAIN;
	ret = vfs_fallocate(req->file, sync->mode, sync->off, sync->len);
	if (ret >= 0)
		fsnotify_modify(req->file);
	io_req_set_res(req, ret, 0);
	return IOU_OK;
}