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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 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 */