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 <linux/kref.h>
20
21/*
22 * Valid flags for a dirty buffer
23 */
24enum {
25	PG_BUSY = 0,
26	PG_MAPPED,
27	PG_CLEAN,
28	PG_NEED_COMMIT,
29	PG_NEED_RESCHED,
30	PG_PARTIAL_READ_FAILED,
31	PG_COMMIT_TO_DS,
32};
33
34struct nfs_inode;
35struct nfs_page {
36	struct list_head	wb_list;	/* Defines state of page: */
37	struct page		*wb_page;	/* page to read in/write out */
38	struct nfs_open_context	*wb_context;	/* File state context info */
39	struct nfs_lock_context	*wb_lock_context;	/* lock 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	struct kref		wb_kref;	/* reference count */
46	unsigned long		wb_flags;
47	struct nfs_writeverf	wb_verf;	/* Commit cookie */
48};
49
50struct nfs_pageio_descriptor;
51struct nfs_pageio_ops {
52	void	(*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
53	bool	(*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
54	int	(*pg_doio)(struct nfs_pageio_descriptor *);
55};
56
57struct nfs_pageio_descriptor {
58	struct list_head	pg_list;
59	unsigned long		pg_bytes_written;
60	size_t			pg_count;
61	size_t			pg_bsize;
62	unsigned int		pg_base;
63	unsigned char		pg_moreio : 1,
64				pg_recoalesce : 1;
65
66	struct inode		*pg_inode;
67	const struct nfs_pageio_ops *pg_ops;
68	int 			pg_ioflags;
69	int			pg_error;
70	const struct rpc_call_ops *pg_rpc_callops;
71	struct pnfs_layout_segment *pg_lseg;
72};
73
74#define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
75
76extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
77					    struct inode *inode,
78					    struct page *page,
79					    unsigned int offset,
80					    unsigned int count);
81extern	void nfs_release_request(struct nfs_page *req);
82
83
84extern	void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
85			     struct inode *inode,
86			     const struct nfs_pageio_ops *pg_ops,
87			     size_t bsize,
88			     int how);
89extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
90				   struct nfs_page *);
91extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
92extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
93extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
94				struct nfs_page *prev,
95				struct nfs_page *req);
96extern  int nfs_wait_on_request(struct nfs_page *);
97extern	void nfs_unlock_request(struct nfs_page *req);
98
99/*
100 * Lock the page of an asynchronous request without getting a new reference
101 */
102static inline int
103nfs_lock_request_dontget(struct nfs_page *req)
104{
105	return !test_and_set_bit(PG_BUSY, &req->wb_flags);
106}
107
108static inline int
109nfs_lock_request(struct nfs_page *req)
110{
111	if (test_and_set_bit(PG_BUSY, &req->wb_flags))
112		return 0;
113	kref_get(&req->wb_kref);
114	return 1;
115}
116
117
118/**
119 * nfs_list_add_request - Insert a request into a list
120 * @req: request
121 * @head: head of list into which to insert the request.
122 */
123static inline void
124nfs_list_add_request(struct nfs_page *req, struct list_head *head)
125{
126	list_add_tail(&req->wb_list, head);
127}
128
129
130/**
131 * nfs_list_remove_request - Remove a request from its wb_list
132 * @req: request
133 */
134static inline void
135nfs_list_remove_request(struct nfs_page *req)
136{
137	if (list_empty(&req->wb_list))
138		return;
139	list_del_init(&req->wb_list);
140}
141
142static inline struct nfs_page *
143nfs_list_entry(struct list_head *head)
144{
145	return list_entry(head, struct nfs_page, wb_list);
146}
147
148static inline
149loff_t req_offset(struct nfs_page *req)
150{
151	return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
152}
153
154#endif /* _LINUX_NFS_PAGE_H */
155