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 enum {
31 PG_BUSY = 0,
32 PG_MAPPED,
33 PG_CLEAN,
34 PG_NEED_COMMIT,
35 PG_NEED_RESCHED,
36 PG_PNFS_COMMIT,
37 };
38
39 struct nfs_inode;
40 struct 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
58 struct 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 int (*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
76 extern 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);
81 extern void nfs_release_request(struct nfs_page *req);
82
83
84 extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
85 pgoff_t idx_start, unsigned int npages, int tag);
86 extern 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);
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 int nfs_wait_on_request(struct nfs_page *);
96 extern void nfs_unlock_request(struct nfs_page *req);
97 extern int nfs_set_page_tag_locked(struct nfs_page *req);
98 extern void nfs_clear_page_tag_locked(struct nfs_page *req);
99
100
101 /*
102 * Lock the page of an asynchronous request without getting a new reference
103 */
104 static inline int
nfs_lock_request_dontget(struct nfs_page * req)105 nfs_lock_request_dontget(struct nfs_page *req)
106 {
107 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
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 */
115 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)116 nfs_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 */
126 static inline void
nfs_list_remove_request(struct nfs_page * req)127 nfs_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
134 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)135 nfs_list_entry(struct list_head *head)
136 {
137 return list_entry(head, struct nfs_page, wb_list);
138 }
139
140 static inline
req_offset(struct nfs_page * req)141 loff_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 */
147