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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/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 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
83}
84
85/*
86 * Lock the page of an asynchronous request
87 */
88static inline int
89nfs_lock_request(struct nfs_page *req)
90{
91 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
92 return 0;
93 atomic_inc(&req->wb_count);
94 return 1;
95}
96
97/**
98 * nfs_list_add_request - Insert a request into a list
99 * @req: request
100 * @head: head of list into which to insert the request.
101 */
102static inline void
103nfs_list_add_request(struct nfs_page *req, struct list_head *head)
104{
105 list_add_tail(&req->wb_list, head);
106 req->wb_list_head = head;
107}
108
109
110/**
111 * nfs_list_remove_request - Remove a request from its wb_list
112 * @req: request
113 */
114static inline void
115nfs_list_remove_request(struct nfs_page *req)
116{
117 if (list_empty(&req->wb_list))
118 return;
119 list_del_init(&req->wb_list);
120 req->wb_list_head = NULL;
121}
122
123static inline int
124nfs_defer_commit(struct nfs_page *req)
125{
126 return !test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags);
127}
128
129static inline void
130nfs_clear_commit(struct nfs_page *req)
131{
132 smp_mb__before_clear_bit();
133 clear_bit(PG_NEED_COMMIT, &req->wb_flags);
134 smp_mb__after_clear_bit();
135}
136
137static inline int
138nfs_defer_reschedule(struct nfs_page *req)
139{
140 return !test_and_set_bit(PG_NEED_RESCHED, &req->wb_flags);
141}
142
143static inline void
144nfs_clear_reschedule(struct nfs_page *req)
145{
146 smp_mb__before_clear_bit();
147 clear_bit(PG_NEED_RESCHED, &req->wb_flags);
148 smp_mb__after_clear_bit();
149}
150
151static inline struct nfs_page *
152nfs_list_entry(struct list_head *head)
153{
154 return list_entry(head, struct nfs_page, wb_list);
155}
156
157static inline
158loff_t req_offset(struct nfs_page *req)
159{
160 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
161}
162
163#endif /* _LINUX_NFS_PAGE_H */