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 unsigned int (*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
62 struct nfs_page *);
63 void (*pg_cleanup)(struct nfs_pageio_descriptor *);
64 };
65
66 struct nfs_rw_ops {
67 const fmode_t rw_mode;
68 struct nfs_pgio_header *(*rw_alloc_header)(void);
69 void (*rw_free_header)(struct nfs_pgio_header *);
70 void (*rw_release)(struct nfs_pgio_header *);
71 int (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
72 struct inode *);
73 void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
74 void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
75 const struct nfs_rpc_ops *,
76 struct rpc_task_setup *, int);
77 };
78
79 struct nfs_pgio_mirror {
80 struct list_head pg_list;
81 unsigned long pg_bytes_written;
82 size_t pg_count;
83 size_t pg_bsize;
84 unsigned int pg_base;
85 unsigned char pg_recoalesce : 1;
86 };
87
88 struct nfs_pageio_descriptor {
89 unsigned char pg_moreio : 1;
90 struct inode *pg_inode;
91 const struct nfs_pageio_ops *pg_ops;
92 const struct nfs_rw_ops *pg_rw_ops;
93 int pg_ioflags;
94 int pg_error;
95 const struct rpc_call_ops *pg_rpc_callops;
96 const struct nfs_pgio_completion_ops *pg_completion_ops;
97 struct pnfs_layout_segment *pg_lseg;
98 struct nfs_direct_req *pg_dreq;
99 void *pg_layout_private;
100 unsigned int pg_bsize; /* default bsize for mirrors */
101
102 u32 pg_mirror_count;
103 struct nfs_pgio_mirror *pg_mirrors;
104 struct nfs_pgio_mirror pg_mirrors_static[1];
105 struct nfs_pgio_mirror *pg_mirrors_dynamic;
106 u32 pg_mirror_idx; /* current mirror */
107 };
108
109 /* arbitrarily selected limit to number of mirrors */
110 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
111
112 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
113
114 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
115 struct page *page,
116 struct nfs_page *last,
117 unsigned int offset,
118 unsigned int count);
119 extern void nfs_release_request(struct nfs_page *);
120
121
122 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
123 struct inode *inode,
124 const struct nfs_pageio_ops *pg_ops,
125 const struct nfs_pgio_completion_ops *compl_ops,
126 const struct nfs_rw_ops *rw_ops,
127 size_t bsize,
128 int how);
129 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
130 struct nfs_page *);
131 extern int nfs_pageio_resend(struct nfs_pageio_descriptor *,
132 struct nfs_pgio_header *);
133 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
134 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
135 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
136 struct nfs_page *prev,
137 struct nfs_page *req);
138 extern int nfs_wait_on_request(struct nfs_page *);
139 extern void nfs_unlock_request(struct nfs_page *req);
140 extern void nfs_unlock_and_release_request(struct nfs_page *);
141 extern int nfs_page_group_lock(struct nfs_page *, bool);
142 extern void nfs_page_group_lock_wait(struct nfs_page *);
143 extern void nfs_page_group_unlock(struct nfs_page *);
144 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
145
146 /*
147 * Lock the page of an asynchronous request
148 */
149 static inline int
nfs_lock_request(struct nfs_page * req)150 nfs_lock_request(struct nfs_page *req)
151 {
152 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
153 }
154
155 /**
156 * nfs_list_add_request - Insert a request into a list
157 * @req: request
158 * @head: head of list into which to insert the request.
159 */
160 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)161 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
162 {
163 list_add_tail(&req->wb_list, head);
164 }
165
166
167 /**
168 * nfs_list_remove_request - Remove a request from its wb_list
169 * @req: request
170 */
171 static inline void
nfs_list_remove_request(struct nfs_page * req)172 nfs_list_remove_request(struct nfs_page *req)
173 {
174 if (list_empty(&req->wb_list))
175 return;
176 list_del_init(&req->wb_list);
177 }
178
179 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)180 nfs_list_entry(struct list_head *head)
181 {
182 return list_entry(head, struct nfs_page, wb_list);
183 }
184
185 static inline
req_offset(struct nfs_page * req)186 loff_t req_offset(struct nfs_page *req)
187 {
188 return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
189 }
190
191 #endif /* _LINUX_NFS_PAGE_H */
192