1/*
2 * linux/include/linux/nfs_page.h
3 *
4 * Copyright (C) 2000 Trond Myklebust
5 *
6 * NFS page cache wrapper.
7 */
8
9#ifndef _LINUX_NFS_PAGE_H
10#define _LINUX_NFS_PAGE_H
11
12
13#include <linux/list.h>
14#include <linux/pagemap.h>
15#include <linux/wait.h>
16#include <linux/sunrpc/auth.h>
17#include <linux/nfs_xdr.h>
18
19#include <linux/kref.h>
20
21/*
22 * Valid flags for a dirty buffer
23 */
24enum {
25	PG_BUSY = 0,		/* nfs_{un}lock_request */
26	PG_MAPPED,		/* page private set for buffered io */
27	PG_CLEAN,		/* write succeeded */
28	PG_COMMIT_TO_DS,	/* used by pnfs layouts */
29	PG_INODE_REF,		/* extra ref held by inode when in writeback */
30	PG_HEADLOCK,		/* page group lock of wb_head */
31	PG_TEARDOWN,		/* page group sync for destroy */
32	PG_UNLOCKPAGE,		/* page group sync bit in read path */
33	PG_UPTODATE,		/* page group sync bit in read path */
34	PG_WB_END,		/* page group sync bit in write path */
35	PG_REMOVE,		/* page group sync bit in write path */
36};
37
38struct nfs_inode;
39struct nfs_page {
40	struct list_head	wb_list;	/* Defines state of page: */
41	struct page		*wb_page;	/* page to read in/write out */
42	struct nfs_open_context	*wb_context;	/* File state context info */
43	struct nfs_lock_context	*wb_lock_context;	/* lock context info */
44	pgoff_t			wb_index;	/* Offset >> PAGE_CACHE_SHIFT */
45	unsigned int		wb_offset,	/* Offset & ~PAGE_CACHE_MASK */
46				wb_pgbase,	/* Start of page data */
47				wb_bytes;	/* Length of request */
48	struct kref		wb_kref;	/* reference count */
49	unsigned long		wb_flags;
50	struct nfs_write_verifier	wb_verf;	/* Commit cookie */
51	struct nfs_page		*wb_this_page;  /* list of reqs for this page */
52	struct nfs_page		*wb_head;       /* head pointer for req list */
53};
54
55struct nfs_pageio_descriptor;
56struct nfs_pageio_ops {
57	void	(*pg_init)(struct nfs_pageio_descriptor *, struct nfs_page *);
58	size_t	(*pg_test)(struct nfs_pageio_descriptor *, struct nfs_page *,
59			   struct nfs_page *);
60	int	(*pg_doio)(struct nfs_pageio_descriptor *);
61	unsigned int	(*pg_get_mirror_count)(struct nfs_pageio_descriptor *,
62				       struct nfs_page *);
63	void	(*pg_cleanup)(struct nfs_pageio_descriptor *);
64};
65
66struct nfs_rw_ops {
67	const fmode_t rw_mode;
68	struct nfs_pgio_header *(*rw_alloc_header)(void);
69	void (*rw_free_header)(struct nfs_pgio_header *);
70	void (*rw_release)(struct nfs_pgio_header *);
71	int  (*rw_done)(struct rpc_task *, struct nfs_pgio_header *,
72			struct inode *);
73	void (*rw_result)(struct rpc_task *, struct nfs_pgio_header *);
74	void (*rw_initiate)(struct nfs_pgio_header *, struct rpc_message *,
75			    const struct nfs_rpc_ops *,
76			    struct rpc_task_setup *, int);
77};
78
79struct nfs_pgio_mirror {
80	struct list_head	pg_list;
81	unsigned long		pg_bytes_written;
82	size_t			pg_count;
83	size_t			pg_bsize;
84	unsigned int		pg_base;
85	unsigned char		pg_recoalesce : 1;
86};
87
88struct nfs_pageio_descriptor {
89	unsigned char		pg_moreio : 1;
90	struct inode		*pg_inode;
91	const struct nfs_pageio_ops *pg_ops;
92	const struct nfs_rw_ops *pg_rw_ops;
93	int 			pg_ioflags;
94	int			pg_error;
95	const struct rpc_call_ops *pg_rpc_callops;
96	const struct nfs_pgio_completion_ops *pg_completion_ops;
97	struct pnfs_layout_segment *pg_lseg;
98	struct nfs_direct_req	*pg_dreq;
99	void			*pg_layout_private;
100	unsigned int		pg_bsize;	/* default bsize for mirrors */
101
102	u32			pg_mirror_count;
103	struct nfs_pgio_mirror	*pg_mirrors;
104	struct nfs_pgio_mirror	pg_mirrors_static[1];
105	struct nfs_pgio_mirror	*pg_mirrors_dynamic;
106	u32			pg_mirror_idx;	/* current mirror */
107};
108
109/* arbitrarily selected limit to number of mirrors */
110#define NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX 16
111
112#define NFS_WBACK_BUSY(req)	(test_bit(PG_BUSY,&(req)->wb_flags))
113
114extern	struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
115					    struct page *page,
116					    struct nfs_page *last,
117					    unsigned int offset,
118					    unsigned int count);
119extern	void nfs_release_request(struct nfs_page *);
120
121
122extern	void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
123			     struct inode *inode,
124			     const struct nfs_pageio_ops *pg_ops,
125			     const struct nfs_pgio_completion_ops *compl_ops,
126			     const struct nfs_rw_ops *rw_ops,
127			     size_t bsize,
128			     int how);
129extern	int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
130				   struct nfs_page *);
131extern  int nfs_pageio_resend(struct nfs_pageio_descriptor *,
132			      struct nfs_pgio_header *);
133extern	void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
134extern	void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
135extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
136				struct nfs_page *prev,
137				struct nfs_page *req);
138extern  int nfs_wait_on_request(struct nfs_page *);
139extern	void nfs_unlock_request(struct nfs_page *req);
140extern	void nfs_unlock_and_release_request(struct nfs_page *);
141extern int nfs_page_group_lock(struct nfs_page *, bool);
142extern void nfs_page_group_lock_wait(struct nfs_page *);
143extern void nfs_page_group_unlock(struct nfs_page *);
144extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
145
146/*
147 * Lock the page of an asynchronous request
148 */
149static inline int
150nfs_lock_request(struct nfs_page *req)
151{
152	return !test_and_set_bit(PG_BUSY, &req->wb_flags);
153}
154
155/**
156 * nfs_list_add_request - Insert a request into a list
157 * @req: request
158 * @head: head of list into which to insert the request.
159 */
160static inline void
161nfs_list_add_request(struct nfs_page *req, struct list_head *head)
162{
163	list_add_tail(&req->wb_list, head);
164}
165
166
167/**
168 * nfs_list_remove_request - Remove a request from its wb_list
169 * @req: request
170 */
171static inline void
172nfs_list_remove_request(struct nfs_page *req)
173{
174	if (list_empty(&req->wb_list))
175		return;
176	list_del_init(&req->wb_list);
177}
178
179static inline struct nfs_page *
180nfs_list_entry(struct list_head *head)
181{
182	return list_entry(head, struct nfs_page, wb_list);
183}
184
185static inline
186loff_t req_offset(struct nfs_page *req)
187{
188	return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
189}
190
191#endif /* _LINUX_NFS_PAGE_H */
192