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_pgio_mirror;
59 struct nfs_pageio_descriptor;
60 struct nfs_pageio_ops {
61 	void	(*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
62 	size_t	(*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
63 			   struct nfs_page *);
64 	int	(*pg_doio)(struct nfs_pageio_descriptor *);
65 	unsigned int	(*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
66 				       struct nfs_page *);
67 	void	(*pg_cleanup)(struct nfs_pageio_descriptor *);
68 	struct nfs_pgio_mirror *
69 		(*pg_get_mirror)(struct nfs_pageio_descriptor *, u32);
70 	u32	(*pg_set_mirror)(struct nfs_pageio_descriptor *, u32);
71 };
72 
73 struct nfs_rw_ops {
74 	struct nfs_pgio_header *(*rw_alloc_header)(void);
75 	void (*rw_free_header)(struct nfs_pgio_header *);
76 	int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
77 			struct inode *);
78 	void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
79 	void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
80 			    const struct nfs_rpc_ops *,
81 			    struct rpc_task_setup *, int);
82 };
83 
84 struct nfs_pgio_mirror {
85 	struct list_head	pg_list;
86 	unsigned long		pg_bytes_written;
87 	size_t			pg_count;
88 	size_t			pg_bsize;
89 	unsigned int		pg_base;
90 	unsigned char		pg_recoalesce : 1;
91 };
92 
93 struct nfs_pageio_descriptor {
94 	struct inode		*pg_inode;
95 	const struct nfs_pageio_ops *pg_ops;
96 	const struct nfs_rw_ops *pg_rw_ops;
97 	int 			pg_ioflags;
98 	int			pg_error;
99 	const struct rpc_call_ops *pg_rpc_callops;
100 	const struct nfs_pgio_completion_ops *pg_completion_ops;
101 	struct pnfs_layout_segment *pg_lseg;
102 	struct nfs_io_completion *pg_io_completion;
103 	struct nfs_direct_req	*pg_dreq;
104 	unsigned int		pg_bsize;	/* default bsize for mirrors */
105 
106 	u32			pg_mirror_count;
107 	struct nfs_pgio_mirror	*pg_mirrors;
108 	struct nfs_pgio_mirror	pg_mirrors_static[1];
109 	struct nfs_pgio_mirror	*pg_mirrors_dynamic;
110 	u32			pg_mirror_idx;	/* current mirror */
111 	unsigned short		pg_maxretrans;
112 	unsigned char		pg_moreio : 1;
113 };
114 
115 /* arbitrarily selected limit to number of mirrors */
116 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
117 
118 #define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
119 
120 extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
121 					    struct page *page,
122 					    unsigned int offset,
123 					    unsigned int count);
124 extern	void nfs_release_request(struct nfs_page *);
125 
126 
127 extern	void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
128 			     struct inode *inode,
129 			     const struct nfs_pageio_ops *pg_ops,
130 			     const struct nfs_pgio_completion_ops *compl_ops,
131 			     const struct nfs_rw_ops *rw_ops,
132 			     size_t bsize,
133 			     int how);
134 extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
135 				   struct nfs_page *);
136 extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
137 			      struct nfs_pgio_header *);
138 extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
139 extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
140 extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
141 				struct nfs_page *prev,
142 				struct nfs_page *req);
143 extern  int nfs_wait_on_request(struct nfs_page *);
144 extern	void nfs_unlock_request(struct nfs_page *req);
145 extern	void nfs_unlock_and_release_request(struct nfs_page *);
146 extern	struct nfs_page *nfs_page_group_lock_head(struct nfs_page *req);
147 extern	int nfs_page_group_lock_subrequests(struct nfs_page *head);
148 extern	void nfs_join_page_group(struct nfs_page *head, struct inode *inode);
149 extern int nfs_page_group_lock(struct nfs_page *);
150 extern void nfs_page_group_unlock(struct nfs_page *);
151 extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
152 extern	int nfs_page_set_headlock(struct nfs_page *req);
153 extern void nfs_page_clear_headlock(struct nfs_page *req);
154 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
155 
156 /*
157  * Lock the page of an asynchronous request
158  */
159 static inline int
nfs_lock_request(struct nfs_page * req)160 nfs_lock_request(struct nfs_page *req)
161 {
162 	return !test_and_set_bit(PG_BUSY, &req->wb_flags);
163 }
164 
165 /**
166  * nfs_list_add_request - Insert a request into a list
167  * @req: request
168  * @head: head of list into which to insert the request.
169  */
170 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)171 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
172 {
173 	list_add_tail(&req->wb_list, head);
174 }
175 
176 /**
177  * nfs_list_move_request - Move a request to a new list
178  * @req: request
179  * @head: head of list into which to insert the request.
180  */
181 static inline void
nfs_list_move_request(struct nfs_page * req,struct list_head * head)182 nfs_list_move_request(struct nfs_page *req, struct list_head *head)
183 {
184 	list_move_tail(&req->wb_list, head);
185 }
186 
187 /**
188  * nfs_list_remove_request - Remove a request from its wb_list
189  * @req: request
190  */
191 static inline void
nfs_list_remove_request(struct nfs_page * req)192 nfs_list_remove_request(struct nfs_page *req)
193 {
194 	if (list_empty(&req->wb_list))
195 		return;
196 	list_del_init(&req->wb_list);
197 }
198 
199 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)200 nfs_list_entry(struct list_head *head)
201 {
202 	return list_entry(head, struct nfs_page, wb_list);
203 }
204 
req_offset(const struct nfs_page * req)205 static inline loff_t req_offset(const struct nfs_page *req)
206 {
207 	return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
208 }
209 
210 static inline struct nfs_open_context *
nfs_req_openctx(struct nfs_page * req)211 nfs_req_openctx(struct nfs_page *req)
212 {
213 	return req->wb_lock_context->open_context;
214 }
215 
216 #endif /* _LINUX_NFS_PAGE_H */
217