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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/sunrpc/auth.h>
17#include <linux/nfs_xdr.h>
18
19#include <linux/kref.h>
20
21/*
22 * Valid flags for the radix tree
23 */
24#define NFS_PAGE_TAG_LOCKED 0
25#define NFS_PAGE_TAG_COMMIT 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 struct page *wb_page; /* page to read in/write out */
38 struct nfs_open_context *wb_context; /* File state context info */
39 atomic_t wb_complete; /* i/os we're waiting for */
40 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
41 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
42 wb_pgbase, /* Start of page data */
43 wb_bytes; /* Length of request */
44 struct kref wb_kref; /* reference count */
45 unsigned long wb_flags;
46 struct nfs_writeverf wb_verf; /* Commit cookie */
47};
48
49struct nfs_pageio_descriptor {
50 struct list_head pg_list;
51 unsigned long pg_bytes_written;
52 size_t pg_count;
53 size_t pg_bsize;
54 unsigned int pg_base;
55
56 struct inode *pg_inode;
57 int (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
58 int pg_ioflags;
59 int pg_error;
60};
61
62#define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
63
64extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
65 struct inode *inode,
66 struct page *page,
67 unsigned int offset,
68 unsigned int count);
69extern void nfs_clear_request(struct nfs_page *req);
70extern void nfs_release_request(struct nfs_page *req);
71
72
73extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
74 pgoff_t idx_start, unsigned int npages, int tag);
75extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
76 struct inode *inode,
77 int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
78 size_t bsize,
79 int how);
80extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
81 struct nfs_page *);
82extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
83extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
84extern int nfs_wait_on_request(struct nfs_page *);
85extern void nfs_unlock_request(struct nfs_page *req);
86extern void nfs_clear_page_tag_locked(struct nfs_page *req);
87
88
89/*
90 * Lock the page of an asynchronous request without getting a new reference
91 */
92static inline int
93nfs_lock_request_dontget(struct nfs_page *req)
94{
95 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
96}
97
98/*
99 * Lock the page of an asynchronous request and take a reference
100 */
101static inline int
102nfs_lock_request(struct nfs_page *req)
103{
104 if (test_and_set_bit(PG_BUSY, &req->wb_flags))
105 return 0;
106 kref_get(&req->wb_kref);
107 return 1;
108}
109
110/**
111 * nfs_list_add_request - Insert a request into a list
112 * @req: request
113 * @head: head of list into which to insert the request.
114 */
115static inline void
116nfs_list_add_request(struct nfs_page *req, struct list_head *head)
117{
118 list_add_tail(&req->wb_list, head);
119}
120
121
122/**
123 * nfs_list_remove_request - Remove a request from its wb_list
124 * @req: request
125 */
126static inline void
127nfs_list_remove_request(struct nfs_page *req)
128{
129 if (list_empty(&req->wb_list))
130 return;
131 list_del_init(&req->wb_list);
132}
133
134static inline struct nfs_page *
135nfs_list_entry(struct list_head *head)
136{
137 return list_entry(head, struct nfs_page, wb_list);
138}
139
140static inline
141loff_t req_offset(struct nfs_page *req)
142{
143 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
144}
145
146#endif /* _LINUX_NFS_PAGE_H */