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Linux kernel mirror (for testing)
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linux
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_DIRTY 0
25#define NFS_PAGE_TAG_WRITEBACK 1
26
27/*
28 * Valid flags for a dirty buffer
29 */
30#define PG_BUSY 0
31#define PG_NEED_COMMIT 1
32#define PG_NEED_RESCHED 2
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 unsigned long 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
50#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
51#define NFS_NEED_COMMIT(req) (test_bit(PG_NEED_COMMIT,&(req)->wb_flags))
52#define NFS_NEED_RESCHED(req) (test_bit(PG_NEED_RESCHED,&(req)->wb_flags))
53
54extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
55 struct inode *inode,
56 struct page *page,
57 unsigned int offset,
58 unsigned int count);
59extern void nfs_clear_request(struct nfs_page *req);
60extern void nfs_release_request(struct nfs_page *req);
61
62
63extern int nfs_scan_lock_dirty(struct nfs_inode *nfsi, struct list_head *dst,
64 unsigned long idx_start, unsigned int npages);
65extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *head, struct list_head *dst,
66 unsigned long idx_start, unsigned int npages);
67extern int nfs_coalesce_requests(struct list_head *, struct list_head *,
68 unsigned int);
69extern int nfs_wait_on_request(struct nfs_page *);
70extern void nfs_unlock_request(struct nfs_page *req);
71extern int nfs_set_page_writeback_locked(struct nfs_page *req);
72extern void nfs_clear_page_writeback(struct nfs_page *req);
73
74
75/*
76 * Lock the page of an asynchronous request without incrementing the wb_count
77 */
78static inline int
79nfs_lock_request_dontget(struct nfs_page *req)
80{
81 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
82}
83
84/*
85 * Lock the page of an asynchronous request
86 */
87static inline int
88nfs_lock_request(struct nfs_page *req)
89{
90 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
91 return 0;
92 atomic_inc(&req->wb_count);
93 return 1;
94}
95
96/**
97 * nfs_list_add_request - Insert a request into a list
98 * @req: request
99 * @head: head of list into which to insert the request.
100 */
101static inline void
102nfs_list_add_request(struct nfs_page *req, struct list_head *head)
103{
104 list_add_tail(&req->wb_list, head);
105 req->wb_list_head = head;
106}
107
108
109/**
110 * nfs_list_remove_request - Remove a request from its wb_list
111 * @req: request
112 */
113static inline void
114nfs_list_remove_request(struct nfs_page *req)
115{
116 if (list_empty(&req->wb_list))
117 return;
118 list_del_init(&req->wb_list);
119 req->wb_list_head = NULL;
120}
121
122static inline int
123nfs_defer_commit(struct nfs_page *req)
124{
125 return !test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags);
126}
127
128static inline void
129nfs_clear_commit(struct nfs_page *req)
130{
131 smp_mb__before_clear_bit();
132 clear_bit(PG_NEED_COMMIT, &req->wb_flags);
133 smp_mb__after_clear_bit();
134}
135
136static inline int
137nfs_defer_reschedule(struct nfs_page *req)
138{
139 return !test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags);
140}
141
142static inline void
143nfs_clear_reschedule(struct nfs_page *req)
144{
145 smp_mb__before_clear_bit();
146 clear_bit(PG_NEED_RESCHED, &req->wb_flags);
147 smp_mb__after_clear_bit();
148}
149
150static inline struct nfs_page *
151nfs_list_entry(struct list_head *head)
152{
153 return list_entry(head, struct nfs_page, wb_list);
154}
155
156static inline
157loff_t req_offset(struct nfs_page *req)
158{
159 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
160}
161
162#endif /* _LINUX_NFS_PAGE_H */