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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/nfs_fs_sb.h>
17#include <linux/sunrpc/auth.h>
18#include <linux/nfs_xdr.h>
19
20#include <asm/atomic.h>
21
22/*
23 * Valid flags for the radix tree
24 */
25#define NFS_PAGE_TAG_DIRTY 0
26#define NFS_PAGE_TAG_WRITEBACK 1
27
28/*
29 * Valid flags for a dirty buffer
30 */
31#define PG_BUSY 0
32#define PG_NEED_COMMIT 1
33#define PG_NEED_RESCHED 2
34
35struct nfs_inode;
36struct nfs_page {
37 struct list_head wb_list, /* Defines state of page: */
38 *wb_list_head; /* read/write/commit */
39 struct page *wb_page; /* page to read in/write out */
40 struct nfs_open_context *wb_context; /* File state context info */
41 atomic_t wb_complete; /* i/os we're waiting for */
42 unsigned long wb_index; /* Offset >> PAGE_CACHE_SHIFT */
43 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
44 wb_pgbase, /* Start of page data */
45 wb_bytes; /* Length of request */
46 atomic_t wb_count; /* reference count */
47 unsigned long wb_flags;
48 struct nfs_writeverf wb_verf; /* Commit cookie */
49};
50
51#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
52#define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
53#define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(req)->wb_flags))
54
55extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
56 struct inode *inode,
57 struct page *page,
58 unsigned int offset,
59 unsigned int count);
60extern void nfs_clear_request(struct nfs_page *req);
61extern void nfs_release_request(struct nfs_page *req);
62
63
64extern int nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
65 unsigned long idx_start, unsigned int npages);
66extern int nfs_scan_list(struct list_head *, struct list_head *,
67 unsigned long, unsigned int);
68extern int nfs_coalesce_requests(struct list_head *, struct list_head *,
69 unsigned int);
70extern int nfs_wait_on_request(struct nfs_page *);
71extern void nfs_unlock_request(struct nfs_page *req);
72extern int nfs_set_page_writeback_locked(struct nfs_page *req);
73extern void nfs_clear_page_writeback(struct nfs_page *req);
74
75
76/*
77 * Lock the page of an asynchronous request without incrementing the wb_count
78 */
79static inline int
80nfs_lock_request_dontget(struct nfs_page *req)
81{
82 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
83 return 0;
84 return 1;
85}
86
87/*
88 * Lock the page of an asynchronous request
89 */
90static inline int
91nfs_lock_request(struct nfs_page *req)
92{
93 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
94 return 0;
95 atomic_inc(&req->wb_count);
96 return 1;
97}
98
99/**
100 * nfs_list_add_request - Insert a request into a list
101 * @req: request
102 * @head: head of list into which to insert the request.
103 */
104static inline void
105nfs_list_add_request(struct nfs_page *req, struct list_head *head)
106{
107 list_add_tail(&req->wb_list, head);
108 req->wb_list_head = head;
109}
110
111
112/**
113 * nfs_list_remove_request - Remove a request from its wb_list
114 * @req: request
115 */
116static inline void
117nfs_list_remove_request(struct nfs_page *req)
118{
119 if (list_empty(&req->wb_list))
120 return;
121 list_del_init(&req->wb_list);
122 req->wb_list_head = NULL;
123}
124
125static inline int
126nfs_defer_commit(struct nfs_page *req)
127{
128 if (test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags))
129 return 0;
130 return 1;
131}
132
133static inline void
134nfs_clear_commit(struct nfs_page *req)
135{
136 smp_mb__before_clear_bit();
137 clear_bit(PG_NEED_COMMIT, &req->wb_flags);
138 smp_mb__after_clear_bit();
139}
140
141static inline int
142nfs_defer_reschedule(struct nfs_page *req)
143{
144 if (test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags))
145 return 0;
146 return 1;
147}
148
149static inline void
150nfs_clear_reschedule(struct nfs_page *req)
151{
152 smp_mb__before_clear_bit();
153 clear_bit(PG_NEED_RESCHED, &req->wb_flags);
154 smp_mb__after_clear_bit();
155}
156
157static inline struct nfs_page *
158nfs_list_entry(struct list_head *head)
159{
160 return list_entry(head, struct nfs_page, wb_list);
161}
162
163static inline
164loff_t req_offset(struct nfs_page *req)
165{
166 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
167}
168
169#endif /* _LINUX_NFS_PAGE_H */