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1/*
2 * include/linux/nfsd/cache.h
3 *
4 * Request reply cache. This was heavily inspired by the
5 * implementation in 4.3BSD/4.4BSD.
6 *
7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8 */
9
10#ifndef NFSCACHE_H
11#define NFSCACHE_H
12
13#include <linux/in.h>
14#include <linux/uio.h>
15
16/*
17 * Representation of a reply cache entry. The first two members *must*
18 * be hash_next and hash_prev.
19 */
20struct svc_cacherep {
21 struct hlist_node c_hash;
22 struct list_head c_lru;
23
24 unsigned char c_state, /* unused, inprog, done */
25 c_type, /* status, buffer */
26 c_secure : 1; /* req came from port < 1024 */
27 struct sockaddr_in c_addr;
28 __be32 c_xid;
29 u32 c_prot;
30 u32 c_proc;
31 u32 c_vers;
32 unsigned long c_timestamp;
33 union {
34 struct kvec u_vec;
35 __be32 u_status;
36 } c_u;
37};
38
39#define c_replvec c_u.u_vec
40#define c_replstat c_u.u_status
41
42/* cache entry states */
43enum {
44 RC_UNUSED,
45 RC_INPROG,
46 RC_DONE
47};
48
49/* return values */
50enum {
51 RC_DROPIT,
52 RC_REPLY,
53 RC_DOIT,
54 RC_INTR
55};
56
57/*
58 * Cache types.
59 * We may want to add more types one day, e.g. for diropres and
60 * attrstat replies. Using cache entries with fixed length instead
61 * of buffer pointers may be more efficient.
62 */
63enum {
64 RC_NOCACHE,
65 RC_REPLSTAT,
66 RC_REPLBUFF,
67};
68
69/*
70 * If requests are retransmitted within this interval, they're dropped.
71 */
72#define RC_DELAY (HZ/5)
73
74int nfsd_reply_cache_init(void);
75void nfsd_reply_cache_shutdown(void);
76int nfsd_cache_lookup(struct svc_rqst *, int);
77void nfsd_cache_update(struct svc_rqst *, int, __be32 *);
78
79#endif /* NFSCACHE_H */