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_FOLIO, /* Tracking a folio (unset for O_DIRECT) */
29 PG_CLEAN, /* write succeeded */
30 PG_COMMIT_TO_DS, /* used by pnfs layouts */
31 PG_INODE_REF, /* extra ref held by inode when in writeback */
32 PG_HEADLOCK, /* page group lock of wb_head */
33 PG_TEARDOWN, /* page group sync for destroy */
34 PG_UNLOCKPAGE, /* page group sync bit in read path */
35 PG_UPTODATE, /* page group sync bit in read path */
36 PG_WB_END, /* page group sync bit in write path */
37 PG_REMOVE, /* page group sync bit in write path */
38 PG_CONTENDED1, /* Is someone waiting for a lock? */
39 PG_CONTENDED2, /* Is someone waiting for a lock? */
40 };
41
42 struct nfs_inode;
43 struct nfs_page {
44 struct list_head wb_list; /* Defines state of page: */
45 union {
46 struct page *wb_page; /* page to read in/write out */
47 struct folio *wb_folio;
48 };
49 struct nfs_lock_context *wb_lock_context; /* lock context info */
50 pgoff_t wb_index; /* Offset >> PAGE_SHIFT */
51 unsigned int wb_offset, /* Offset & ~PAGE_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_write_verifier wb_verf; /* Commit cookie */
57 struct nfs_page *wb_this_page; /* list of reqs for this page */
58 struct nfs_page *wb_head; /* head pointer for req list */
59 unsigned short wb_nio; /* Number of I/O attempts */
60 };
61
62 struct nfs_pgio_mirror;
63 struct nfs_pageio_descriptor;
64 struct nfs_pageio_ops {
65 void (*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
66 size_t (*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
67 struct nfs_page *);
68 int (*pg_doio)(struct nfs_pageio_descriptor *);
69 unsigned int (*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
70 struct nfs_page *);
71 void (*pg_cleanup)(struct nfs_pageio_descriptor *);
72 struct nfs_pgio_mirror *
73 (*pg_get_mirror)(struct nfs_pageio_descriptor *, u32);
74 u32 (*pg_set_mirror)(struct nfs_pageio_descriptor *, u32);
75 };
76
77 struct nfs_rw_ops {
78 struct nfs_pgio_header *(*rw_alloc_header)(void);
79 void (*rw_free_header)(struct nfs_pgio_header *);
80 int (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
81 struct inode *);
82 void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
83 void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
84 const struct nfs_rpc_ops *,
85 struct rpc_task_setup *, int);
86 };
87
88 struct nfs_pgio_mirror {
89 struct list_head pg_list;
90 unsigned long pg_bytes_written;
91 size_t pg_count;
92 size_t pg_bsize;
93 unsigned int pg_base;
94 unsigned char pg_recoalesce : 1;
95 };
96
97 struct nfs_pageio_descriptor {
98 struct inode *pg_inode;
99 const struct nfs_pageio_ops *pg_ops;
100 const struct nfs_rw_ops *pg_rw_ops;
101 int pg_ioflags;
102 int pg_error;
103 const struct rpc_call_ops *pg_rpc_callops;
104 const struct nfs_pgio_completion_ops *pg_completion_ops;
105 struct pnfs_layout_segment *pg_lseg;
106 struct nfs_io_completion *pg_io_completion;
107 struct nfs_direct_req *pg_dreq;
108 #ifdef CONFIG_NFS_FSCACHE
109 void *pg_netfs;
110 #endif
111 unsigned int pg_bsize; /* default bsize for mirrors */
112
113 u32 pg_mirror_count;
114 struct nfs_pgio_mirror *pg_mirrors;
115 struct nfs_pgio_mirror pg_mirrors_static[1];
116 struct nfs_pgio_mirror *pg_mirrors_dynamic;
117 u32 pg_mirror_idx; /* current mirror */
118 unsigned short pg_maxretrans;
119 unsigned char pg_moreio : 1;
120 };
121
122 /* arbitrarily selected limit to number of mirrors */
123 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
124
125 #define NFS_WBACK_BUSY(req) (test_bit(PG_BUSY,&(req)->wb_flags))
126
127 extern struct nfs_page *nfs_page_create_from_page(struct nfs_open_context *ctx,
128 struct page *page,
129 unsigned int pgbase,
130 loff_t offset,
131 unsigned int count);
132 extern struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx,
133 struct folio *folio,
134 unsigned int offset,
135 unsigned int count);
136 extern void nfs_release_request(struct nfs_page *);
137
138
139 extern void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
140 struct inode *inode,
141 const struct nfs_pageio_ops *pg_ops,
142 const struct nfs_pgio_completion_ops *compl_ops,
143 const struct nfs_rw_ops *rw_ops,
144 size_t bsize,
145 int how);
146 extern int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
147 struct nfs_page *);
148 extern int nfs_pageio_resend(struct nfs_pageio_descriptor *,
149 struct nfs_pgio_header *);
150 extern void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
151 extern void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
152 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
153 struct nfs_page *prev,
154 struct nfs_page *req);
155 extern int nfs_wait_on_request(struct nfs_page *);
156 extern void nfs_unlock_request(struct nfs_page *req);
157 extern void nfs_unlock_and_release_request(struct nfs_page *);
158 extern struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req);
159 extern int nfs_page_group_lock_subrequests(struct nfs_page *head);
160 extern void nfs_join_page_group(struct nfs_page *head,
161 struct nfs_commit_info *cinfo,
162 struct inode *inode);
163 extern int nfs_page_group_lock(struct nfs_page *);
164 extern void nfs_page_group_unlock(struct nfs_page *);
165 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
166 extern int nfs_page_set_headlock(struct nfs_page *req);
167 extern void nfs_page_clear_headlock(struct nfs_page *req);
168 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
169
170 /**
171 * nfs_page_to_folio - Retrieve a struct folio for the request
172 * @req: pointer to a struct nfs_page
173 *
174 * If a folio was assigned to @req, then return it, otherwise return NULL.
175 */
nfs_page_to_folio(const struct nfs_page * req)176 static inline struct folio *nfs_page_to_folio(const struct nfs_page *req)
177 {
178 if (test_bit(PG_FOLIO, &req->wb_flags))
179 return req->wb_folio;
180 return NULL;
181 }
182
183 /**
184 * nfs_page_to_page - Retrieve a struct page for the request
185 * @req: pointer to a struct nfs_page
186 * @pgbase: folio byte offset
187 *
188 * Return the page containing the byte that is at offset @pgbase relative
189 * to the start of the folio.
190 * Note: The request starts at offset @req->wb_pgbase.
191 */
nfs_page_to_page(const struct nfs_page * req,size_t pgbase)192 static inline struct page *nfs_page_to_page(const struct nfs_page *req,
193 size_t pgbase)
194 {
195 struct folio *folio = nfs_page_to_folio(req);
196
197 if (folio == NULL)
198 return req->wb_page;
199 return folio_page(folio, pgbase >> PAGE_SHIFT);
200 }
201
202 /**
203 * nfs_page_to_inode - Retrieve an inode for the request
204 * @req: pointer to a struct nfs_page
205 */
nfs_page_to_inode(const struct nfs_page * req)206 static inline struct inode *nfs_page_to_inode(const struct nfs_page *req)
207 {
208 struct folio *folio = nfs_page_to_folio(req);
209
210 if (folio == NULL)
211 return page_file_mapping(req->wb_page)->host;
212 return folio_file_mapping(folio)->host;
213 }
214
215 /**
216 * nfs_page_max_length - Retrieve the maximum possible length for a request
217 * @req: pointer to a struct nfs_page
218 *
219 * Returns the maximum possible length of a request
220 */
nfs_page_max_length(const struct nfs_page * req)221 static inline size_t nfs_page_max_length(const struct nfs_page *req)
222 {
223 struct folio *folio = nfs_page_to_folio(req);
224
225 if (folio == NULL)
226 return PAGE_SIZE;
227 return folio_size(folio);
228 }
229
230 /*
231 * Lock the page of an asynchronous request
232 */
233 static inline int
nfs_lock_request(struct nfs_page * req)234 nfs_lock_request(struct nfs_page *req)
235 {
236 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
237 }
238
239 /**
240 * nfs_list_add_request - Insert a request into a list
241 * @req: request
242 * @head: head of list into which to insert the request.
243 */
244 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)245 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
246 {
247 list_add_tail(&req->wb_list, head);
248 }
249
250 /**
251 * nfs_list_move_request - Move a request to a new list
252 * @req: request
253 * @head: head of list into which to insert the request.
254 */
255 static inline void
nfs_list_move_request(struct nfs_page * req,struct list_head * head)256 nfs_list_move_request(struct nfs_page *req, struct list_head *head)
257 {
258 list_move_tail(&req->wb_list, head);
259 }
260
261 /**
262 * nfs_list_remove_request - Remove a request from its wb_list
263 * @req: request
264 */
265 static inline void
nfs_list_remove_request(struct nfs_page * req)266 nfs_list_remove_request(struct nfs_page *req)
267 {
268 if (list_empty(&req->wb_list))
269 return;
270 list_del_init(&req->wb_list);
271 }
272
273 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)274 nfs_list_entry(struct list_head *head)
275 {
276 return list_entry(head, struct nfs_page, wb_list);
277 }
278
req_offset(const struct nfs_page * req)279 static inline loff_t req_offset(const struct nfs_page *req)
280 {
281 return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
282 }
283
284 static inline struct nfs_open_context *
nfs_req_openctx(struct nfs_page * req)285 nfs_req_openctx(struct nfs_page *req)
286 {
287 return req->wb_lock_context->open_context;
288 }
289
290 #endif /* _LINUX_NFS_PAGE_H */
291