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_CLEAN,
33 PG_NEED_COMMIT,
34 PG_NEED_RESCHED,
35 };
36
37 struct nfs_inode;
38 struct nfs_page {
39 struct list_head wb_list; /* Defines state of page: */
40 struct page *wb_page; /* page to read in/write out */
41 struct nfs_open_context *wb_context; /* File state context info */
42 atomic_t wb_complete; /* i/os we're waiting for */
43 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
44 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
45 wb_pgbase, /* Start of page data */
46 wb_bytes; /* Length of request */
47 struct kref wb_kref; /* reference count */
48 unsigned long wb_flags;
49 struct nfs_writeverf wb_verf; /* Commit cookie */
50 };
51
52 struct nfs_pageio_descriptor {
53 struct list_head pg_list;
54 unsigned long pg_bytes_written;
55 size_t pg_count;
56 size_t pg_bsize;
57 unsigned int pg_base;
58
59 struct inode *pg_inode;
60 int (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
61 int pg_ioflags;
62 int pg_error;
63 };
64
65 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
66
67 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
68 struct inode *inode,
69 struct page *page,
70 unsigned int offset,
71 unsigned int count);
72 extern void nfs_clear_request(struct nfs_page *req);
73 extern void nfs_release_request(struct nfs_page *req);
74
75
76 extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
77 pgoff_t idx_start, unsigned int npages, int tag);
78 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
79 struct inode *inode,
80 int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
81 size_t bsize,
82 int how);
83 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
84 struct nfs_page *);
85 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
86 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
87 extern int nfs_wait_on_request(struct nfs_page *);
88 extern void nfs_unlock_request(struct nfs_page *req);
89 extern int nfs_set_page_tag_locked(struct nfs_page *req);
90 extern void nfs_clear_page_tag_locked(struct nfs_page *req);
91
92
93 /*
94 * Lock the page of an asynchronous request without getting a new reference
95 */
96 static inline int
nfs_lock_request_dontget(struct nfs_page * req)97 nfs_lock_request_dontget(struct nfs_page *req)
98 {
99 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
100 }
101
102 /**
103 * nfs_list_add_request - Insert a request into a list
104 * @req: request
105 * @head: head of list into which to insert the request.
106 */
107 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)108 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
109 {
110 list_add_tail(&req->wb_list, head);
111 }
112
113
114 /**
115 * nfs_list_remove_request - Remove a request from its wb_list
116 * @req: request
117 */
118 static inline void
nfs_list_remove_request(struct nfs_page * req)119 nfs_list_remove_request(struct nfs_page *req)
120 {
121 if (list_empty(&req->wb_list))
122 return;
123 list_del_init(&req->wb_list);
124 }
125
126 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)127 nfs_list_entry(struct list_head *head)
128 {
129 return list_entry(head, struct nfs_page, wb_list);
130 }
131
132 static inline
req_offset(struct nfs_page * req)133 loff_t req_offset(struct nfs_page *req)
134 {
135 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
136 }
137
138 #endif /* _LINUX_NFS_PAGE_H */
139