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