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 PG_PARTIAL_READ_FAILED,
38 };
39
40 struct nfs_inode;
41 struct nfs_page {
42 union {
43 struct list_head wb_list; /* Defines state of page: */
44 struct pnfs_layout_segment *wb_commit_lseg; /* Used when PG_PNFS_COMMIT set */
45 };
46 struct page *wb_page; /* page to read in/write out */
47 struct nfs_open_context *wb_context; /* File state context info */
48 struct nfs_lock_context *wb_lock_context; /* lock context info */
49 atomic_t wb_complete; /* i/os we're waiting for */
50 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
51 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
52 wb_pgbase, /* Start of page data */
53 wb_bytes; /* Length of request */
54 struct kref wb_kref; /* reference count */
55 unsigned long wb_flags;
56 struct nfs_writeverf wb_verf; /* Commit cookie */
57 };
58
59 struct nfs_pageio_descriptor;
60 struct nfs_pageio_ops {
61 void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
62 bool (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *, struct nfs_page *);
63 int (*pg_doio)(struct nfs_pageio_descriptor *);
64 };
65
66 struct nfs_pageio_descriptor {
67 struct list_head pg_list;
68 unsigned long pg_bytes_written;
69 size_t pg_count;
70 size_t pg_bsize;
71 unsigned int pg_base;
72 unsigned char pg_moreio : 1,
73 pg_recoalesce : 1;
74
75 struct inode *pg_inode;
76 const struct nfs_pageio_ops *pg_ops;
77 int pg_ioflags;
78 int pg_error;
79 const struct rpc_call_ops *pg_rpc_callops;
80 struct pnfs_layout_segment *pg_lseg;
81 };
82
83 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
84
85 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
86 struct inode *inode,
87 struct page *page,
88 unsigned int offset,
89 unsigned int count);
90 extern void nfs_release_request(struct nfs_page *req);
91
92
93 extern int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
94 pgoff_t idx_start, unsigned int npages, int tag);
95 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
96 struct inode *inode,
97 const struct nfs_pageio_ops *pg_ops,
98 size_t bsize,
99 int how);
100 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
101 struct nfs_page *);
102 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
103 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
104 extern bool nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
105 struct nfs_page *prev,
106 struct nfs_page *req);
107 extern int nfs_wait_on_request(struct nfs_page *);
108 extern void nfs_unlock_request(struct nfs_page *req);
109 extern int nfs_set_page_tag_locked(struct nfs_page *req);
110 extern void nfs_clear_page_tag_locked(struct nfs_page *req);
111
112 /*
113 * Lock the page of an asynchronous request without getting a new reference
114 */
115 static inline int
nfs_lock_request_dontget(struct nfs_page * req)116 nfs_lock_request_dontget(struct nfs_page *req)
117 {
118 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
119 }
120
121 /**
122 * nfs_list_add_request - Insert a request into a list
123 * @req: request
124 * @head: head of list into which to insert the request.
125 */
126 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)127 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
128 {
129 list_add_tail(&req->wb_list, head);
130 }
131
132
133 /**
134 * nfs_list_remove_request - Remove a request from its wb_list
135 * @req: request
136 */
137 static inline void
nfs_list_remove_request(struct nfs_page * req)138 nfs_list_remove_request(struct nfs_page *req)
139 {
140 if (list_empty(&req->wb_list))
141 return;
142 list_del_init(&req->wb_list);
143 }
144
145 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)146 nfs_list_entry(struct list_head *head)
147 {
148 return list_entry(head, struct nfs_page, wb_list);
149 }
150
151 static inline
req_offset(struct nfs_page * req)152 loff_t req_offset(struct nfs_page *req)
153 {
154 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
155 }
156
157 #endif /* _LINUX_NFS_PAGE_H */
158