xref: /linux/fs/nfs/fscache.h (revision 4c62e9764ab403d42f9b8871b1241fe7812f19d4)
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  */
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  * Invalidate the contents of fscache for this inode.  This will not sleep.
157  */
158 static inline void nfs_fscache_invalidate(struct inode *inode)
159 {
160 	fscache_invalidate(NFS_I(inode)->fscache);
161 }
162 
163 /*
164  * Wait for an object to finish being invalidated.
165  */
166 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
167 {
168 	fscache_wait_on_invalidate(NFS_I(inode)->fscache);
169 }
170 
171 /*
172  * indicate the client caching state as readable text
173  */
174 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
175 {
176 	if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
177 		return "yes";
178 	return "no ";
179 }
180 
181 #else /* CONFIG_NFS_FSCACHE */
182 static inline int nfs_fscache_register(void) { return 0; }
183 static inline void nfs_fscache_unregister(void) {}
184 
185 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
186 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
187 
188 static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
189 
190 static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {}
191 static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {}
192 static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {}
193 static inline void nfs_fscache_set_inode_cookie(struct inode *inode,
194 						struct file *filp) {}
195 static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}
196 
197 static inline int nfs_fscache_release_page(struct page *page, gfp_t gfp)
198 {
199 	return 1; /* True: may release page */
200 }
201 static inline void nfs_fscache_invalidate_page(struct page *page,
202 					       struct inode *inode) {}
203 static inline void nfs_fscache_wait_on_page_write(struct nfs_inode *nfsi,
204 						  struct page *page) {}
205 
206 static inline int nfs_readpage_from_fscache(struct nfs_open_context *ctx,
207 					    struct inode *inode,
208 					    struct page *page)
209 {
210 	return -ENOBUFS;
211 }
212 static inline int nfs_readpages_from_fscache(struct nfs_open_context *ctx,
213 					     struct inode *inode,
214 					     struct address_space *mapping,
215 					     struct list_head *pages,
216 					     unsigned *nr_pages)
217 {
218 	return -ENOBUFS;
219 }
220 static inline void nfs_readpage_to_fscache(struct inode *inode,
221 					   struct page *page, int sync) {}
222 
223 
224 static inline void nfs_fscache_invalidate(struct inode *inode) {}
225 static inline void nfs_fscache_wait_on_invalidate(struct inode *inode) {}
226 
227 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
228 {
229 	return "no ";
230 }
231 
232 #endif /* CONFIG_NFS_FSCACHE */
233 #endif /* _NFS_FSCACHE_H */
234