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, /* nfs_{un}lock_request */
26 PG_MAPPED, /* page private set for buffered io */
27 PG_CLEAN, /* write succeeded */
28 PG_COMMIT_TO_DS, /* used by pnfs layouts */
29 PG_INODE_REF, /* extra ref held by inode when in writeback */
30 PG_HEADLOCK, /* page group lock of wb_head */
31 PG_TEARDOWN, /* page group sync for destroy */
32 PG_UNLOCKPAGE, /* page group sync bit in read path */
33 PG_UPTODATE, /* page group sync bit in read path */
34 PG_WB_END, /* page group sync bit in write path */
35 PG_REMOVE, /* page group sync bit in write path */
36 };
37
38 struct nfs_inode;
39 struct nfs_page {
40 struct list_head wb_list; /* Defines state of page: */
41 struct page *wb_page; /* page to read in/write out */
42 struct nfs_open_context *wb_context; /* File state context info */
43 struct nfs_lock_context *wb_lock_context; /* lock context info */
44 pgoff_t wb_index; /* Offset >> PAGE_CACHE_SHIFT */
45 unsigned int wb_offset, /* Offset & ~PAGE_CACHE_MASK */
46 wb_pgbase, /* Start of page data */
47 wb_bytes; /* Length of request */
48 struct kref wb_kref; /* reference count */
49 unsigned long wb_flags;
50 struct nfs_write_verifier wb_verf; /* Commit cookie */
51 struct nfs_page *wb_this_page; /* list of reqs for this page */
52 struct nfs_page *wb_head; /* head pointer for req list */
53 };
54
55 struct nfs_pageio_descriptor;
56 struct nfs_pageio_ops {
57 void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
58 size_t (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
59 struct nfs_page *);
60 int (*pg_doio)(struct nfs_pageio_descriptor *);
61 };
62
63 struct nfs_rw_ops {
64 const fmode_t rw_mode;
65 struct nfs_pgio_header *(*rw_alloc_header)(void);
66 void (*rw_free_header)(struct nfs_pgio_header *);
67 void (*rw_release)(struct nfs_pgio_header *);
68 int (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
69 struct inode *);
70 void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
71 void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
72 struct rpc_task_setup *, int);
73 };
74
75 struct nfs_pageio_descriptor {
76 struct list_head pg_list;
77 unsigned long pg_bytes_written;
78 size_t pg_count;
79 size_t pg_bsize;
80 unsigned int pg_base;
81 unsigned char pg_moreio : 1,
82 pg_recoalesce : 1;
83
84 struct inode *pg_inode;
85 const struct nfs_pageio_ops *pg_ops;
86 const struct nfs_rw_ops *pg_rw_ops;
87 int pg_ioflags;
88 int pg_error;
89 const struct rpc_call_ops *pg_rpc_callops;
90 const struct nfs_pgio_completion_ops *pg_completion_ops;
91 struct pnfs_layout_segment *pg_lseg;
92 struct nfs_direct_req *pg_dreq;
93 void *pg_layout_private;
94 };
95
96 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
97
98 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
99 struct page *page,
100 struct nfs_page *last,
101 unsigned int offset,
102 unsigned int count);
103 extern void nfs_release_request(struct nfs_page *);
104
105
106 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
107 struct inode *inode,
108 const struct nfs_pageio_ops *pg_ops,
109 const struct nfs_pgio_completion_ops *compl_ops,
110 const struct nfs_rw_ops *rw_ops,
111 size_t bsize,
112 int how);
113 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
114 struct nfs_page *);
115 extern int nfs_pageio_resend(struct nfs_pageio_descriptor *,
116 struct nfs_pgio_header *);
117 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
118 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
119 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
120 struct nfs_page *prev,
121 struct nfs_page *req);
122 extern int nfs_wait_on_request(struct nfs_page *);
123 extern void nfs_unlock_request(struct nfs_page *req);
124 extern void nfs_unlock_and_release_request(struct nfs_page *);
125 extern int nfs_page_group_lock(struct nfs_page *, bool);
126 extern void nfs_page_group_lock_wait(struct nfs_page *);
127 extern void nfs_page_group_unlock(struct nfs_page *);
128 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
129
130 /*
131 * Lock the page of an asynchronous request
132 */
133 static inline int
nfs_lock_request(struct nfs_page * req)134 nfs_lock_request(struct nfs_page *req)
135 {
136 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
137 }
138
139 /**
140 * nfs_list_add_request - Insert a request into a list
141 * @req: request
142 * @head: head of list into which to insert the request.
143 */
144 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)145 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
146 {
147 list_add_tail(&req->wb_list, head);
148 }
149
150
151 /**
152 * nfs_list_remove_request - Remove a request from its wb_list
153 * @req: request
154 */
155 static inline void
nfs_list_remove_request(struct nfs_page * req)156 nfs_list_remove_request(struct nfs_page *req)
157 {
158 if (list_empty(&req->wb_list))
159 return;
160 list_del_init(&req->wb_list);
161 }
162
163 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)164 nfs_list_entry(struct list_head *head)
165 {
166 return list_entry(head, struct nfs_page, wb_list);
167 }
168
169 static inline
req_offset(struct nfs_page * req)170 loff_t req_offset(struct nfs_page *req)
171 {
172 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
173 }
174
175 #endif /* _LINUX_NFS_PAGE_H */
176