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nfs_page.h
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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  */
24 enum {
25  PG_BUSY = 0,
26  PG_MAPPED,
27  PG_CLEAN,
28  PG_NEED_COMMIT,
29  PG_NEED_RESCHED,
30  PG_COMMIT_TO_DS,
31 };
32 
33 struct nfs_inode;
34 struct nfs_page {
35  struct list_head wb_list; /* Defines state of page: */
36  struct page *wb_page; /* page to read in/write out */
37  struct nfs_open_context *wb_context; /* File state context info */
38  struct nfs_lock_context *wb_lock_context; /* lock context info */
39  pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
40  unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
41  wb_pgbase, /* Start of page data */
42  wb_bytes; /* Length of request */
43  struct kref wb_kref; /* reference count */
44  unsigned long wb_flags;
45  struct nfs_write_verifier wb_verf; /* Commit cookie */
46 };
47 
48 struct nfs_pageio_descriptor;
49 struct nfs_pageio_ops {
50  void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
51  bool (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
52  int (*pg_doio)(struct nfs_pageio_descriptor *);
53 };
54 
55 struct nfs_pageio_descriptor {
56  struct list_head pg_list;
57  unsigned long pg_bytes_written;
58  size_t pg_count;
59  size_t pg_bsize;
60  unsigned int pg_base;
61  unsigned char pg_moreio : 1,
62  pg_recoalesce : 1;
63 
64  struct inode *pg_inode;
65  const struct nfs_pageio_ops *pg_ops;
66  int pg_ioflags;
67  int pg_error;
68  const struct rpc_call_ops *pg_rpc_callops;
69  const struct nfs_pgio_completion_ops *pg_completion_ops;
70  struct pnfs_layout_segment *pg_lseg;
71  struct nfs_direct_req *pg_dreq;
72  void *pg_layout_private;
73 };
74 
75 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
76 
77 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
78  struct inode *inode,
79  struct page *page,
80  unsigned int offset,
81  unsigned int count);
82 extern void nfs_release_request(struct nfs_page *req);
83 
84 
85 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
86  struct inode *inode,
87  const struct nfs_pageio_ops *pg_ops,
88  const struct nfs_pgio_completion_ops *compl_ops,
89  size_t bsize,
90  int how);
91 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
92  struct nfs_page *);
93 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
94 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
95 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
96  struct nfs_page *prev,
97  struct nfs_page *req);
98 extern int nfs_wait_on_request(struct nfs_page *);
99 extern void nfs_unlock_request(struct nfs_page *req);
100 extern void nfs_unlock_and_release_request(struct nfs_page *req);
101 
102 /*
103  * Lock the page of an asynchronous request
104  */
105 static inline int
106 nfs_lock_request(struct nfs_page *req)
107 {
108  return !test_and_set_bit(PG_BUSY, &req->wb_flags);
109 }
110 
116 static inline void
117 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
118 {
119  list_add_tail(&req->wb_list, head);
120 }
121 
122 
127 static inline void
128 nfs_list_remove_request(struct nfs_page *req)
129 {
130  if (list_empty(&req->wb_list))
131  return;
132  list_del_init(&req->wb_list);
133 }
134 
135 static inline struct nfs_page *
136 nfs_list_entry(struct list_head *head)
137 {
138  return list_entry(head, struct nfs_page, wb_list);
139 }
140 
141 static inline
142 loff_t req_offset(struct nfs_page *req)
143 {
144  return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
145 }
146 
147 #endif /* _LINUX_NFS_PAGE_H */
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