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