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 */
25enum {
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
42struct nfs_inode;
43struct 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
62struct nfs_pgio_mirror;
63struct nfs_pageio_descriptor;
64struct 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
77struct 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
88struct 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
97struct 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
127extern 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);
132extern 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);
136extern	void nfs_release_request(struct nfs_page *);
137
138
139extern	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);
146extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
147				   struct nfs_page *);
148extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
149			      struct nfs_pgio_header *);
150extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
151extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
152extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
153				struct nfs_page *prev,
154				struct nfs_page *req);
155extern  int nfs_wait_on_request(struct nfs_page *);
156extern	void nfs_unlock_request(struct nfs_page *req);
157extern	void nfs_unlock_and_release_request(struct nfs_page *);
158extern	struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req);
159extern	int nfs_page_group_lock_subrequests(struct nfs_page *head);
160extern void nfs_join_page_group(struct nfs_page *head,
161				struct nfs_commit_info *cinfo,
162				struct inode *inode);
163extern int nfs_page_group_lock(struct nfs_page *);
164extern void nfs_page_group_unlock(struct nfs_page *);
165extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
166extern	int nfs_page_set_headlock(struct nfs_page *req);
167extern void nfs_page_clear_headlock(struct nfs_page *req);
168extern 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 */
176static 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 */
192static 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 */
206static 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 */
221static 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 */
233static inline int
234nfs_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 */
244static inline void
245nfs_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 */
255static inline void
256nfs_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 */
265static inline void
266nfs_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
273static inline struct nfs_page *
274nfs_list_entry(struct list_head *head)
275{
276	return list_entry(head, struct nfs_page, wb_list);
277}
278
279static 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
284static inline struct nfs_open_context *
285nfs_req_openctx(struct nfs_page *req)
286{
287	return req->wb_lock_context->open_context;
288}
289
290#endif /* _LINUX_NFS_PAGE_H */
291