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1/* NFS filesystem cache interface definitions
2 *
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#ifndef _NFS_FSCACHE_H
13#define _NFS_FSCACHE_H
14
15#include <linux/nfs_fs.h>
16#include <linux/nfs_mount.h>
17#include <linux/nfs4_mount.h>
18#include <linux/fscache.h>
19
20#ifdef CONFIG_NFS_FSCACHE
21
22/*
23 * set of NFS FS-Cache objects that form a superblock key
24 */
25struct nfs_fscache_key {
26 struct rb_node node;
27 struct nfs_client *nfs_client; /* the server */
28
29 /* the elements of the unique key - as used by nfs_compare_super() and
30 * nfs_compare_mount_options() to distinguish superblocks */
31 struct {
32 struct {
33 unsigned long s_flags; /* various flags
34 * (& NFS_MS_MASK) */
35 } super;
36
37 struct {
38 struct nfs_fsid fsid;
39 int flags;
40 unsigned int rsize; /* read size */
41 unsigned int wsize; /* write size */
42 unsigned int acregmin; /* attr cache timeouts */
43 unsigned int acregmax;
44 unsigned int acdirmin;
45 unsigned int acdirmax;
46 } nfs_server;
47
48 struct {
49 rpc_authflavor_t au_flavor;
50 } rpc_auth;
51
52 /* uniquifier - can be used if nfs_server.flags includes
53 * NFS_MOUNT_UNSHARED */
54 u8 uniq_len;
55 char uniquifier[0];
56 } key;
57};
58
59/*
60 * Definition of the auxiliary data attached to NFS inode storage objects
61 * within the cache.
62 *
63 * The contents of this struct are recorded in the on-disk local cache in the
64 * auxiliary data attached to the data storage object backing an inode. This
65 * permits coherency to be managed when a new inode binds to an already extant
66 * cache object.
67 */
68struct nfs_fscache_inode_auxdata {
69 struct timespec mtime;
70 struct timespec ctime;
71 u64 change_attr;
72};
73
74/*
75 * fscache-index.c
76 */
77extern struct fscache_netfs nfs_fscache_netfs;
78extern const struct fscache_cookie_def nfs_fscache_server_index_def;
79extern const struct fscache_cookie_def nfs_fscache_super_index_def;
80extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
81
82extern int nfs_fscache_register(void);
83extern void nfs_fscache_unregister(void);
84
85/*
86 * fscache.c
87 */
88extern void nfs_fscache_get_client_cookie(struct nfs_client *);
89extern void nfs_fscache_release_client_cookie(struct nfs_client *);
90
91extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
92extern void nfs_fscache_release_super_cookie(struct super_block *);
93
94extern void nfs_fscache_init_inode(struct inode *);
95extern void nfs_fscache_clear_inode(struct inode *);
96extern void nfs_fscache_open_file(struct inode *, struct file *);
97
98extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
99extern int nfs_fscache_release_page(struct page *, gfp_t);
100
101extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
102 struct inode *, struct page *);
103extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
104 struct inode *, struct address_space *,
105 struct list_head *, unsigned *);
106extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
107
108/*
109 * wait for a page to complete writing to the cache
110 */
111static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
112 struct page *page)
113{
114 if (PageFsCache(page))
115 fscache_wait_on_page_write(nfsi->fscache, page);
116}
117
118/*
119 * release the caching state associated with a page if undergoing complete page
120 * invalidation
121 */
122static inline void nfs_fscache_invalidate_page(struct page *page,
123 struct inode *inode)
124{
125 if (PageFsCache(page))
126 __nfs_fscache_invalidate_page(page, inode);
127}
128
129/*
130 * Retrieve a page from an inode data storage object.
131 */
132static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
133 struct inode *inode,
134 struct page *page)
135{
136 if (NFS_I(inode)->fscache)
137 return __nfs_readpage_from_fscache(ctx, inode, page);
138 return -ENOBUFS;
139}
140
141/*
142 * Retrieve a set of pages from an inode data storage object.
143 */
144static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
145 struct inode *inode,
146 struct address_space *mapping,
147 struct list_head *pages,
148 unsigned *nr_pages)
149{
150 if (NFS_I(inode)->fscache)
151 return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
152 nr_pages);
153 return -ENOBUFS;
154}
155
156/*
157 * Store a page newly fetched from the server in an inode data storage object
158 * in the cache.
159 */
160static inline void nfs_readpage_to_fscache(struct inode *inode,
161 struct page *page,
162 int sync)
163{
164 if (PageFsCache(page))
165 __nfs_readpage_to_fscache(inode, page, sync);
166}
167
168/*
169 * Invalidate the contents of fscache for this inode. This will not sleep.
170 */
171static inline void nfs_fscache_invalidate(struct inode *inode)
172{
173 fscache_invalidate(NFS_I(inode)->fscache);
174}
175
176/*
177 * Wait for an object to finish being invalidated.
178 */
179static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
180{
181 fscache_wait_on_invalidate(NFS_I(inode)->fscache);
182}
183
184/*
185 * indicate the client caching state as readable text
186 */
187static inline const char *nfs_server_fscache_state(struct nfs_server *server)
188{
189 if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
190 return "yes";
191 return "no ";
192}
193
194#else /* CONFIG_NFS_FSCACHE */
195static inline int nfs_fscache_register(void) { return 0; }
196static inline void nfs_fscache_unregister(void) {}
197
198static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
199static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
200
201static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
202
203static inline void nfs_fscache_init_inode(struct inode *inode) {}
204static inline void nfs_fscache_clear_inode(struct inode *inode) {}
205static inline void nfs_fscache_open_file(struct inode *inode,
206 struct file *filp) {}
207
208static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
209{
210 return 1; /* True: may release page */
211}
212static inline void nfs_fscache_invalidate_page(struct page *page,
213 struct inode *inode) {}
214static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
215 struct page *page) {}
216
217static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
218 struct inode *inode,
219 struct page *page)
220{
221 return -ENOBUFS;
222}
223static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
224 struct inode *inode,
225 struct address_space *mapping,
226 struct list_head *pages,
227 unsigned *nr_pages)
228{
229 return -ENOBUFS;
230}
231static inline void nfs_readpage_to_fscache(struct inode *inode,
232 struct page *page, int sync) {}
233
234
235static inline void nfs_fscache_invalidate(struct inode *inode) {}
236static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
237
238static inline const char *nfs_server_fscache_state(struct nfs_server *server)
239{
240 return "no ";
241}
242
243#endif /* CONFIG_NFS_FSCACHE */
244#endif /* _NFS_FSCACHE_H */