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fscache.h
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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 ([email protected])
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  */
25 struct 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  * fscache-index.c
61  */
62 extern struct fscache_netfs nfs_fscache_netfs;
63 extern const struct fscache_cookie_def nfs_fscache_server_index_def;
64 extern const struct fscache_cookie_def nfs_fscache_super_index_def;
65 extern const struct fscache_cookie_def nfs_fscache_inode_object_def;
66 
67 extern int nfs_fscache_register(void);
68 extern void nfs_fscache_unregister(void);
69 
70 /*
71  * fscache.c
72  */
73 extern void nfs_fscache_get_client_cookie(struct nfs_client *);
74 extern void nfs_fscache_release_client_cookie(struct nfs_client *);
75 
76 extern void nfs_fscache_get_super_cookie(struct super_block *, const char *, int);
77 extern void nfs_fscache_release_super_cookie(struct super_block *);
78 
79 extern void nfs_fscache_init_inode_cookie(struct inode *);
80 extern void nfs_fscache_release_inode_cookie(struct inode *);
81 extern void nfs_fscache_zap_inode_cookie(struct inode *);
82 extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *);
83 extern void nfs_fscache_reset_inode_cookie(struct inode *);
84 
85 extern void __nfs_fscache_invalidate_page(struct page *, struct inode *);
86 extern int nfs_fscache_release_page(struct page *, gfp_t);
87 
88 extern int __nfs_readpage_from_fscache(struct nfs_open_context *,
89  struct inode *, struct page *);
90 extern int __nfs_readpages_from_fscache(struct nfs_open_context *,
91  struct inode *, struct address_space *,
92  struct list_head *, unsigned *);
93 extern void __nfs_readpage_to_fscache(struct inode *, struct page *, int);
94 
95 /*
96  * wait for a page to complete writing to the cache
97  */
98 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
99  struct page *page)
100 {
101  if (PageFsCache(page))
102  fscache_wait_on_page_write(nfsi->fscache, page);
103 }
104 
105 /*
106  * release the caching state associated with a page if undergoing complete page
107  * invalidation
108  */
109 static inline void nfs_fscache_invalidate_page(struct page *page,
110  struct inode *inode)
111 {
112  if (PageFsCache(page))
113  __nfs_fscache_invalidate_page(page, inode);
114 }
115 
116 /*
117  * Retrieve a page from an inode data storage object.
118  */
119 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
120  struct inode *inode,
121  struct page *page)
122 {
123  if (NFS_I(inode)->fscache)
124  return __nfs_readpage_from_fscache(ctx, inode, page);
125  return -ENOBUFS;
126 }
127 
128 /*
129  * Retrieve a set of pages from an inode data storage object.
130  */
131 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
132  struct inode *inode,
133  struct address_space *mapping,
134  struct list_head *pages,
135  unsigned *nr_pages)
136 {
137  if (NFS_I(inode)->fscache)
138  return __nfs_readpages_from_fscache(ctx, inode, mapping, pages,
139  nr_pages);
140  return -ENOBUFS;
141 }
142 
143 /*
144  * Store a page newly fetched from the server in an inode data storage object
145  * in the cache.
146  */
147 static inline void nfs_readpage_to_fscache(struct inode *inode,
148  struct page *page,
149  int sync)
150 {
151  if (PageFsCache(page))
152  __nfs_readpage_to_fscache(inode, page, sync);
153 }
154 
155 /*
156  * indicate the client caching state as readable text
157  */
158 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
159 {
160  if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
161  return "yes";
162  return "no ";
163 }
164 
165 
166 #else /* CONFIG_NFS_FSCACHE */
167 static inline int nfs_fscache_register(void) { return 0; }
168 static inline void nfs_fscache_unregister(void) {}
169 
170 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
171 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
172 
173 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
174 
175 static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {}
176 static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {}
177 static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {}
178 static inline void nfs_fscache_set_inode_cookie(struct inode *inode,
179  struct file *filp) {}
180 static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}
181 
182 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
183 {
184  return 1; /* True: may release page */
185 }
186 static inline void nfs_fscache_invalidate_page(struct page *page,
187  struct inode *inode) {}
188 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
189  struct page *page) {}
190 
191 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
192  struct inode *inode,
193  struct page *page)
194 {
195  return -ENOBUFS;
196 }
197 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
198  struct inode *inode,
199  struct address_space *mapping,
200  struct list_head *pages,
201  unsigned *nr_pages)
202 {
203  return -ENOBUFS;
204 }
205 static inline void nfs_readpage_to_fscache(struct inode *inode,
206  struct page *page, int sync) {}
207 
208 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
209 {
210  return "no ";
211 }
212 
213 #endif /* CONFIG_NFS_FSCACHE */
214 #endif /* _NFS_FSCACHE_H */
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