1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Request reply cache. This was heavily inspired by the
4 * implementation in 4.3BSD/4.4BSD.
5 *
6 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
7 */
8
9#ifndef NFSCACHE_H
10#define NFSCACHE_H
11
12#include <linux/sunrpc/svc.h>
13#include "netns.h"
14
15/*
16 * Representation of a reply cache entry.
17 *
18 * Note that we use a sockaddr_in6 to hold the address instead of the more
19 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage
20 * is much larger than a sockaddr_in6.
21 */
22struct nfsd_cacherep {
23 struct {
24 /* Keep often-read xid, csum in the same cache line: */
25 __be32 k_xid;
26 __wsum k_csum;
27 u32 k_proc;
28 u32 k_prot;
29 u32 k_vers;
30 unsigned int k_len;
31 struct sockaddr_in6 k_addr;
32 } c_key;
33
34 struct rb_node c_node;
35 struct list_head c_lru;
36 unsigned char c_state, /* unused, inprog, done */
37 c_type, /* status, buffer */
38 c_secure : 1; /* req came from port < 1024 */
39 unsigned long c_timestamp;
40 union {
41 struct kvec u_vec;
42 __be32 u_status;
43 } c_u;
44};
45
46#define c_replvec c_u.u_vec
47#define c_replstat c_u.u_status
48
49/* cache entry states */
50enum {
51 RC_UNUSED,
52 RC_INPROG,
53 RC_DONE
54};
55
56/* return values */
57enum {
58 RC_DROPIT,
59 RC_REPLY,
60 RC_DOIT
61};
62
63/*
64 * Cache types.
65 * We may want to add more types one day, e.g. for diropres and
66 * attrstat replies. Using cache entries with fixed length instead
67 * of buffer pointers may be more efficient.
68 */
69enum {
70 RC_NOCACHE,
71 RC_REPLSTAT,
72 RC_REPLBUFF,
73};
74
75/* Cache entries expire after this time period */
76#define RC_EXPIRE (120 * HZ)
77
78/* Checksum this amount of the request */
79#define RC_CSUMLEN (256U)
80
81int nfsd_drc_slab_create(void);
82void nfsd_drc_slab_free(void);
83int nfsd_net_reply_cache_init(struct nfsd_net *nn);
84void nfsd_net_reply_cache_destroy(struct nfsd_net *nn);
85int nfsd_reply_cache_init(struct nfsd_net *);
86void nfsd_reply_cache_shutdown(struct nfsd_net *);
87int nfsd_cache_lookup(struct svc_rqst *rqstp,
88 struct nfsd_cacherep **cacherep);
89void nfsd_cache_update(struct svc_rqst *rqstp, struct nfsd_cacherep *rp,
90 int cachetype, __be32 *statp);
91int nfsd_reply_cache_stats_show(struct seq_file *m, void *v);
92
93#endif /* NFSCACHE_H */
94

source code of linux/fs/nfsd/cache.h