1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * linux/include/linux/nfs_page.h
4 *
5 * Copyright (C) 2000 Trond Myklebust
6 *
7 * NFS page cache wrapper.
8 */
9
10 #ifndef _LINUX_NFS_PAGE_H
11 #define _LINUX_NFS_PAGE_H
12
13
14 #include <linux/list.h>
15 #include <linux/pagemap.h>
16 #include <linux/wait.h>
17 #include <linux/sunrpc/auth.h>
18 #include <linux/nfs_xdr.h>
19
20 #include <linux/kref.h>
21
22 /*
23 * Valid flags for a dirty buffer
24 */
25 enum {
26 PG_BUSY = 0, /* nfs_{un}lock_request */
27 PG_MAPPED, /* page private set for buffered io */
28 PG_CLEAN, /* write succeeded */
29 PG_COMMIT_TO_DS, /* used by pnfs layouts */
30 PG_INODE_REF, /* extra ref held by inode when in writeback */
31 PG_HEADLOCK, /* page group lock of wb_head */
32 PG_TEARDOWN, /* page group sync for destroy */
33 PG_UNLOCKPAGE, /* page group sync bit in read path */
34 PG_UPTODATE, /* page group sync bit in read path */
35 PG_WB_END, /* page group sync bit in write path */
36 PG_REMOVE, /* page group sync bit in write path */
37 PG_CONTENDED1, /* Is someone waiting for a lock? */
38 PG_CONTENDED2, /* Is someone waiting for a lock? */
39 };
40
41 struct nfs_inode;
42 struct nfs_page {
43 struct list_head wb_list; /* Defines state of page: */
44 struct page *wb_page; /* page to read in/write out */
45 struct nfs_lock_context *wb_lock_context; /* lock context info */
46 pgoff_t wb_index; /* Offset >> PAGE_SHIFT */
47 unsigned int wb_offset, /* Offset & ~PAGE_MASK */
48 wb_pgbase, /* Start of page data */
49 wb_bytes; /* Length of request */
50 struct kref wb_kref; /* reference count */
51 unsigned long wb_flags;
52 struct nfs_write_verifier wb_verf; /* Commit cookie */
53 struct nfs_page *wb_this_page; /* list of reqs for this page */
54 struct nfs_page *wb_head; /* head pointer for req list */
55 unsigned short wb_nio; /* Number of I/O attempts */
56 };
57
58 struct nfs_pageio_descriptor;
59 struct nfs_pageio_ops {
60 void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
61 size_t (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
62 struct nfs_page *);
63 int (*pg_doio)(struct nfs_pageio_descriptor *);
64 unsigned int (*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
65 struct nfs_page *);
66 void (*pg_cleanup)(struct nfs_pageio_descriptor *);
67 };
68
69 struct nfs_rw_ops {
70 struct nfs_pgio_header *(*rw_alloc_header)(void);
71 void (*rw_free_header)(struct nfs_pgio_header *);
72 int (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
73 struct inode *);
74 void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
75 void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
76 const struct nfs_rpc_ops *,
77 struct rpc_task_setup *, int);
78 };
79
80 struct nfs_pgio_mirror {
81 struct list_head pg_list;
82 unsigned long pg_bytes_written;
83 size_t pg_count;
84 size_t pg_bsize;
85 unsigned int pg_base;
86 unsigned char pg_recoalesce : 1;
87 };
88
89 struct nfs_pageio_descriptor {
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_io_completion *pg_io_completion;
99 struct nfs_direct_req *pg_dreq;
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 unsigned short pg_maxretrans;
108 unsigned char pg_moreio : 1;
109 };
110
111 /* arbitrarily selected limit to number of mirrors */
112 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
113
114 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
115
116 extern struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
117 struct page *page,
118 unsigned int offset,
119 unsigned int count);
120 extern void nfs_release_request(struct nfs_page *);
121
122
123 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
124 struct inode *inode,
125 const struct nfs_pageio_ops *pg_ops,
126 const struct nfs_pgio_completion_ops *compl_ops,
127 const struct nfs_rw_ops *rw_ops,
128 size_t bsize,
129 int how);
130 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
131 struct nfs_page *);
132 extern int nfs_pageio_resend(struct nfs_pageio_descriptor *,
133 struct nfs_pgio_header *);
134 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
135 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
136 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
137 struct nfs_page *prev,
138 struct nfs_page *req);
139 extern int nfs_wait_on_request(struct nfs_page *);
140 extern void nfs_unlock_request(struct nfs_page *req);
141 extern void nfs_unlock_and_release_request(struct nfs_page *);
142 extern int nfs_page_group_lock(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 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
146
147 /*
148 * Lock the page of an asynchronous request
149 */
150 static inline int
nfs_lock_request(struct nfs_page * req)151 nfs_lock_request(struct nfs_page *req)
152 {
153 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
154 }
155
156 /**
157 * nfs_list_add_request - Insert a request into a list
158 * @req: request
159 * @head: head of list into which to insert the request.
160 */
161 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)162 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
163 {
164 list_add_tail(&req->wb_list, head);
165 }
166
167 /**
168 * nfs_list_move_request - Move a request to a new list
169 * @req: request
170 * @head: head of list into which to insert the request.
171 */
172 static inline void
nfs_list_move_request(struct nfs_page * req,struct list_head * head)173 nfs_list_move_request(struct nfs_page *req, struct list_head *head)
174 {
175 list_move_tail(&req->wb_list, head);
176 }
177
178 /**
179 * nfs_list_remove_request - Remove a request from its wb_list
180 * @req: request
181 */
182 static inline void
nfs_list_remove_request(struct nfs_page * req)183 nfs_list_remove_request(struct nfs_page *req)
184 {
185 if (list_empty(&req->wb_list))
186 return;
187 list_del_init(&req->wb_list);
188 }
189
190 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)191 nfs_list_entry(struct list_head *head)
192 {
193 return list_entry(head, struct nfs_page, wb_list);
194 }
195
196 static inline
req_offset(struct nfs_page * req)197 loff_t req_offset(struct nfs_page *req)
198 {
199 return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
200 }
201
202 static inline struct nfs_open_context *
nfs_req_openctx(struct nfs_page * req)203 nfs_req_openctx(struct nfs_page *req)
204 {
205 return req->wb_lock_context->open_context;
206 }
207
208 #endif /* _LINUX_NFS_PAGE_H */
209
