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Linux kernel mirror (for testing)
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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, struct inode *inode);
161extern int nfs_page_group_lock(struct nfs_page *);
162extern void nfs_page_group_unlock(struct nfs_page *);
163extern bool nfs_page_group_sync_on_bit(struct nfs_page *, unsigned int);
164extern int nfs_page_set_headlock(struct nfs_page *req);
165extern void nfs_page_clear_headlock(struct nfs_page *req);
166extern bool nfs_async_iocounter_wait(struct rpc_task *, struct nfs_lock_context *);
167
168/**
169 * nfs_page_to_folio - Retrieve a struct folio for the request
170 * @req: pointer to a struct nfs_page
171 *
172 * If a folio was assigned to @req, then return it, otherwise return NULL.
173 */
174static inline struct folio *nfs_page_to_folio(const struct nfs_page *req)
175{
176 if (test_bit(PG_FOLIO, &req->wb_flags))
177 return req->wb_folio;
178 return NULL;
179}
180
181/**
182 * nfs_page_to_page - Retrieve a struct page for the request
183 * @req: pointer to a struct nfs_page
184 * @pgbase: folio byte offset
185 *
186 * Return the page containing the byte that is at offset @pgbase relative
187 * to the start of the folio.
188 * Note: The request starts at offset @req->wb_pgbase.
189 */
190static inline struct page *nfs_page_to_page(const struct nfs_page *req,
191 size_t pgbase)
192{
193 struct folio *folio = nfs_page_to_folio(req);
194
195 if (folio == NULL)
196 return req->wb_page;
197 return folio_page(folio, pgbase >> PAGE_SHIFT);
198}
199
200/**
201 * nfs_page_to_inode - Retrieve an inode for the request
202 * @req: pointer to a struct nfs_page
203 */
204static inline struct inode *nfs_page_to_inode(const struct nfs_page *req)
205{
206 struct folio *folio = nfs_page_to_folio(req);
207
208 if (folio == NULL)
209 return page_file_mapping(req->wb_page)->host;
210 return folio_file_mapping(folio)->host;
211}
212
213/**
214 * nfs_page_max_length - Retrieve the maximum possible length for a request
215 * @req: pointer to a struct nfs_page
216 *
217 * Returns the maximum possible length of a request
218 */
219static inline size_t nfs_page_max_length(const struct nfs_page *req)
220{
221 struct folio *folio = nfs_page_to_folio(req);
222
223 if (folio == NULL)
224 return PAGE_SIZE;
225 return folio_size(folio);
226}
227
228/*
229 * Lock the page of an asynchronous request
230 */
231static inline int
232nfs_lock_request(struct nfs_page *req)
233{
234 return !test_and_set_bit(PG_BUSY, &req->wb_flags);
235}
236
237/**
238 * nfs_list_add_request - Insert a request into a list
239 * @req: request
240 * @head: head of list into which to insert the request.
241 */
242static inline void
243nfs_list_add_request(struct nfs_page *req, struct list_head *head)
244{
245 list_add_tail(&req->wb_list, head);
246}
247
248/**
249 * nfs_list_move_request - Move a request to a new list
250 * @req: request
251 * @head: head of list into which to insert the request.
252 */
253static inline void
254nfs_list_move_request(struct nfs_page *req, struct list_head *head)
255{
256 list_move_tail(&req->wb_list, head);
257}
258
259/**
260 * nfs_list_remove_request - Remove a request from its wb_list
261 * @req: request
262 */
263static inline void
264nfs_list_remove_request(struct nfs_page *req)
265{
266 if (list_empty(&req->wb_list))
267 return;
268 list_del_init(&req->wb_list);
269}
270
271static inline struct nfs_page *
272nfs_list_entry(struct list_head *head)
273{
274 return list_entry(head, struct nfs_page, wb_list);
275}
276
277static inline loff_t req_offset(const struct nfs_page *req)
278{
279 return (((loff_t)req->wb_index) << PAGE_SHIFT) + req->wb_offset;
280}
281
282static inline struct nfs_open_context *
283nfs_req_openctx(struct nfs_page *req)
284{
285 return req->wb_lock_context->open_context;
286}
287
288#endif /* _LINUX_NFS_PAGE_H */