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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 */
30enum {
31 PG_BUSY = 0,
32 PG_MAPPED,
33 PG_CLEAN,
34 PG_NEED_COMMIT,
35 PG_NEED_RESCHED,
36 PG_PNFS_COMMIT,
37};
38
39struct nfs_inode;
40struct nfs_page {
41 union {
42 struct list_head wb_list; /* Defines state of page: */
43 struct pnfs_layout_segment *wb_commit_lseg; /* Used when PG_PNFS_COMMIT set */
44 };
45 struct page *wb_page; /* page to read in/write out */
46 struct nfs_open_context *wb_context; /* File state context info */
47 struct nfs_lock_context *wb_lock_context; /* lock context info */
48 atomic_t wb_complete; /* i/os we're waiting for */
49 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
50 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
51 wb_pgbase, /* Start of page data */
52 wb_bytes; /* Length of request */
53 struct kref wb_kref; /* reference count */
54 unsigned long wb_flags;
55 struct nfs_writeverf wb_verf; /* Commit cookie */
56};
57
58struct nfs_pageio_descriptor {
59 struct list_head pg_list;
60 unsigned long pg_bytes_written;
61 size_t pg_count;
62 size_t pg_bsize;
63 unsigned int pg_base;
64 char pg_moreio;
65
66 struct inode *pg_inode;
67 int (*pg_doio)(struct nfs_pageio_descriptor *);
68 int pg_ioflags;
69 int pg_error;
70 struct pnfs_layout_segment *pg_lseg;
71 bool (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
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 int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
85 pgoff_t idx_start, unsigned int npages, int tag);
86extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
87 struct inode *inode,
88 int (*doio)(struct nfs_pageio_descriptor *desc),
89 size_t bsize,
90 int how);
91extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
92 struct nfs_page *);
93extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
94extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
95extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
96 struct nfs_page *prev,
97 struct nfs_page *req);
98extern int nfs_wait_on_request(struct nfs_page *);
99extern void nfs_unlock_request(struct nfs_page *req);
100extern int nfs_set_page_tag_locked(struct nfs_page *req);
101extern void nfs_clear_page_tag_locked(struct nfs_page *req);
102
103
104/*
105 * Lock the page of an asynchronous request without getting a new reference
106 */
107static inline int
108nfs_lock_request_dontget(struct nfs_page *req)
109{
110 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
111}
112
113/**
114 * nfs_list_add_request - Insert a request into a list
115 * @req: request
116 * @head: head of list into which to insert the request.
117 */
118static inline void
119nfs_list_add_request(struct nfs_page *req, struct list_head *head)
120{
121 list_add_tail(&req->wb_list, head);
122}
123
124
125/**
126 * nfs_list_remove_request - Remove a request from its wb_list
127 * @req: request
128 */
129static inline void
130nfs_list_remove_request(struct nfs_page *req)
131{
132 if (list_empty(&req->wb_list))
133 return;
134 list_del_init(&req->wb_list);
135}
136
137static inline struct nfs_page *
138nfs_list_entry(struct list_head *head)
139{
140 return list_entry(head, struct nfs_page, wb_list);
141}
142
143static inline
144loff_t req_offset(struct nfs_page *req)
145{
146 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
147}
148
149#endif /* _LINUX_NFS_PAGE_H */