1/*
2 * linux/include/linux/nfs_page.h
3 *
4 * Copyright (C) 2000 Trond Myklebust
5 *
6 * NFS page cache wrapper.
7 */
8
9#ifndef _LINUX_NFS_PAGE_H
10#define _LINUX_NFS_PAGE_H
11
12
13#include <linux/list.h>
14#include <linux/pagemap.h>
15#include <linux/wait.h>
16#include <linux/sunrpc/auth.h>
17#include <linux/nfs_xdr.h>
18
19#include <asm/atomic.h>
20
21/*
22 * Valid flags for the radix tree
23 */
24#define NFS_PAGE_TAG_WRITEBACK	0
25
26/*
27 * Valid flags for a dirty buffer
28 */
29#define PG_BUSY			0
30#define PG_NEED_COMMIT		1
31#define PG_NEED_RESCHED		2
32#define PG_NEED_FLUSH		3
33
34struct nfs_inode;
35struct nfs_page {
36	struct list_head	wb_list,	/* Defines state of page: */
37				*wb_list_head;	/*      read/write/commit */
38	struct page		*wb_page;	/* page to read in/write out */
39	struct nfs_open_context	*wb_context;	/* File state context info */
40	atomic_t		wb_complete;	/* i/os we're waiting for */
41	pgoff_t			wb_index;	/* Offset >> PAGE_CACHE_SHIFT */
42	unsigned int		wb_offset,	/* Offset & ~PAGE_CACHE_MASK */
43				wb_pgbase,	/* Start of page data */
44				wb_bytes;	/* Length of request */
45	atomic_t		wb_count;	/* reference count */
46	unsigned long		wb_flags;
47	struct nfs_writeverf	wb_verf;	/* Commit cookie */
48};
49
50struct nfs_pageio_descriptor {
51	struct list_head	pg_list;
52	unsigned long		pg_bytes_written;
53	size_t			pg_count;
54	size_t			pg_bsize;
55	unsigned int		pg_base;
56
57	struct inode		*pg_inode;
58	int			(*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
59	int 			pg_ioflags;
60	int			pg_error;
61};
62
63#define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
64
65extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
66					    struct inode *inode,
67					    struct page *page,
68					    unsigned int offset,
69					    unsigned int count);
70extern	void nfs_clear_request(struct nfs_page *req);
71extern	void nfs_release_request(struct nfs_page *req);
72
73
74extern	int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
75			  pgoff_t idx_start, unsigned int npages);
76extern	void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
77			     struct inode *inode,
78			     int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
79			     size_t bsize,
80			     int how);
81extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
82				   struct nfs_page *);
83extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
84extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
85extern  int nfs_wait_on_request(struct nfs_page *);
86extern	void nfs_unlock_request(struct nfs_page *req);
87extern  int nfs_set_page_writeback_locked(struct nfs_page *req);
88extern  void nfs_clear_page_writeback(struct nfs_page *req);
89
90
91/*
92 * Lock the page of an asynchronous request without incrementing the wb_count
93 */
94static inline int
95nfs_lock_request_dontget(struct nfs_page *req)
96{
97	return !test_and_set_bit(PG_BUSY, &req->wb_flags);
98}
99
100/*
101 * Lock the page of an asynchronous request
102 */
103static inline int
104nfs_lock_request(struct nfs_page *req)
105{
106	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
107		return 0;
108	atomic_inc(&req->wb_count);
109	return 1;
110}
111
112/**
113 * nfs_list_add_request - Insert a request into a list
114 * @req: request
115 * @head: head of list into which to insert the request.
116 */
117static inline void
118nfs_list_add_request(struct nfs_page *req, struct list_head *head)
119{
120	list_add_tail(&req->wb_list, head);
121	req->wb_list_head = head;
122}
123
124
125/**
126 * nfs_list_remove_request - Remove a request from its wb_list
127 * @req: request
128 */
129static inline void
130nfs_list_remove_request(struct nfs_page *req)
131{
132	if (list_empty(&req->wb_list))
133		return;
134	list_del_init(&req->wb_list);
135	req->wb_list_head = NULL;
136}
137
138static inline struct nfs_page *
139nfs_list_entry(struct list_head *head)
140{
141	return list_entry(head, struct nfs_page, wb_list);
142}
143
144static inline
145loff_t req_offset(struct nfs_page *req)
146{
147	return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
148}
149
150#endif /* _LINUX_NFS_PAGE_H */
151