Root/fs/nfsd/cache.h

1/*
2 * Request reply cache. This was heavily inspired by the
3 * implementation in 4.3BSD/4.4BSD.
4 *
5 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6 */
7
8#ifndef NFSCACHE_H
9#define NFSCACHE_H
10
11#include <linux/sunrpc/svc.h>
12
13/*
14 * Representation of a reply cache entry.
15 */
16struct svc_cacherep {
17    struct hlist_node c_hash;
18    struct list_head c_lru;
19
20    unsigned char c_state, /* unused, inprog, done */
21                c_type, /* status, buffer */
22                c_secure : 1; /* req came from port < 1024 */
23    struct sockaddr_in c_addr;
24    __be32 c_xid;
25    u32 c_prot;
26    u32 c_proc;
27    u32 c_vers;
28    unsigned long c_timestamp;
29    union {
30        struct kvec u_vec;
31        __be32 u_status;
32    } c_u;
33};
34
35#define c_replvec c_u.u_vec
36#define c_replstat c_u.u_status
37
38/* cache entry states */
39enum {
40    RC_UNUSED,
41    RC_INPROG,
42    RC_DONE
43};
44
45/* return values */
46enum {
47    RC_DROPIT,
48    RC_REPLY,
49    RC_DOIT,
50    RC_INTR
51};
52
53/*
54 * Cache types.
55 * We may want to add more types one day, e.g. for diropres and
56 * attrstat replies. Using cache entries with fixed length instead
57 * of buffer pointers may be more efficient.
58 */
59enum {
60    RC_NOCACHE,
61    RC_REPLSTAT,
62    RC_REPLBUFF,
63};
64
65/*
66 * If requests are retransmitted within this interval, they're dropped.
67 */
68#define RC_DELAY (HZ/5)
69
70int nfsd_reply_cache_init(void);
71void nfsd_reply_cache_shutdown(void);
72int nfsd_cache_lookup(struct svc_rqst *, int);
73void nfsd_cache_update(struct svc_rqst *, int, __be32 *);
74
75#ifdef CONFIG_NFSD_V4
76void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp);
77#else /* CONFIG_NFSD_V4 */
78static inline void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
79{
80}
81#endif /* CONFIG_NFSD_V4 */
82
83#endif /* NFSCACHE_H */
84

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