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_open_context	*wb_context;	/* File state context info */
46 	struct nfs_lock_context	*wb_lock_context;	/* lock context info */
47 	pgoff_t			wb_index;	/* Offset >> PAGE_SHIFT */
48 	unsigned int		wb_offset,	/* Offset & ~PAGE_MASK */
49 				wb_pgbase,	/* Start of page data */
50 				wb_bytes;	/* Length of request */
51 	struct kref		wb_kref;	/* reference count */
52 	unsigned long		wb_flags;
53 	struct nfs_write_verifier	wb_verf;	/* Commit cookie */
54 	struct nfs_page		*wb_this_page;  /* list of reqs for this page */
55 	struct nfs_page		*wb_head;       /* head pointer for req list */
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 	unsigned char		pg_moreio : 1;
91 	struct inode		*pg_inode;
92 	const struct nfs_pageio_ops *pg_ops;
93 	const struct nfs_rw_ops *pg_rw_ops;
94 	int 			pg_ioflags;
95 	int			pg_error;
96 	const struct rpc_call_ops *pg_rpc_callops;
97 	const struct nfs_pgio_completion_ops *pg_completion_ops;
98 	struct pnfs_layout_segment *pg_lseg;
99 	struct nfs_io_completion *pg_io_completion;
100 	struct nfs_direct_req	*pg_dreq;
101 	unsigned int		pg_bsize;	/* default bsize for mirrors */
102 
103 	u32			pg_mirror_count;
104 	struct nfs_pgio_mirror	*pg_mirrors;
105 	struct nfs_pgio_mirror	pg_mirrors_static[1];
106 	struct nfs_pgio_mirror	*pg_mirrors_dynamic;
107 	u32			pg_mirror_idx;	/* current mirror */
108 };
109 
110 /* arbitrarily selected limit to number of mirrors */
111 #define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
112 
113 #define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
114 
115 extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
116 					    struct page *page,
117 					    struct nfs_page *last,
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	int nfs_page_set_headlock(struct nfs_page *req);
146 extern void nfs_page_clear_headlock(struct nfs_page *req);
147 extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
148 
149 /*
150  * Lock the page of an asynchronous request
151  */
152 static inline int
nfs_lock_request(struct nfs_page * req)153 nfs_lock_request(struct nfs_page *req)
154 {
155 	return !test_and_set_bit(PG_BUSY, &req->wb_flags);
156 }
157 
158 /**
159  * nfs_list_add_request - Insert a request into a list
160  * @req: request
161  * @head: head of list into which to insert the request.
162  */
163 static inline void
nfs_list_add_request(struct nfs_page * req,struct list_head * head)164 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
165 {
166 	list_add_tail(&req->wb_list, head);
167 }
168 
169 /**
170  * nfs_list_move_request - Move a request to a new list
171  * @req: request
172  * @head: head of list into which to insert the request.
173  */
174 static inline void
nfs_list_move_request(struct nfs_page * req,struct list_head * head)175 nfs_list_move_request(struct nfs_page *req, struct list_head *head)
176 {
177 	list_move_tail(&req->wb_list, head);
178 }
179 
180 /**
181  * nfs_list_remove_request - Remove a request from its wb_list
182  * @req: request
183  */
184 static inline void
nfs_list_remove_request(struct nfs_page * req)185 nfs_list_remove_request(struct nfs_page *req)
186 {
187 	if (list_empty(&req->wb_list))
188 		return;
189 	list_del_init(&req->wb_list);
190 }
191 
192 static inline struct nfs_page *
nfs_list_entry(struct list_head * head)193 nfs_list_entry(struct list_head *head)
194 {
195 	return list_entry(head, struct nfs_page, wb_list);
196 }
197 
198 static inline
req_offset(struct nfs_page * req)199 loff_t req_offset(struct nfs_page *req)
200 {
201 	return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
202 }
203 
204 #endif /* _LINUX_NFS_PAGE_H */
205