include/linux/nfsd/cache.h

   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.
  18  */
  19 struct svc_cacherep {
  20         struct hlist_node       c_hash;
  21         struct list_head        c_lru;
  22
  23         unsigned char           c_state,        /* unused, inprog, done */
  24                                 c_type,         /* status, buffer */
  25                                 c_secure : 1;   /* req came from port < 1024 */
  26         struct sockaddr_in      c_addr;
  27         __be32                  c_xid;
  28         u32                     c_prot;
  29         u32                     c_proc;
  30         u32                     c_vers;
  31         unsigned long           c_timestamp;
  32         union {
  33                 struct kvec     u_vec;
  34                 __be32          u_status;
  35         }                       c_u;
  36 };
  37
  38 #define c_replvec               c_u.u_vec
  39 #define c_replstat              c_u.u_status
  40
  41 /* cache entry states */
  42 enum {
  43         RC_UNUSED,
  44         RC_INPROG,
  45         RC_DONE
  46 };
  47
  48 /* return values */
  49 enum {
  50         RC_DROPIT,
  51         RC_REPLY,
  52         RC_DOIT,
  53         RC_INTR
  54 };
  55
  56 /*
  57  * Cache types.
  58  * We may want to add more types one day, e.g. for diropres and
  59  * attrstat replies. Using cache entries with fixed length instead
  60  * of buffer pointers may be more efficient.
  61  */
  62 enum {
  63         RC_NOCACHE,
  64         RC_REPLSTAT,
  65         RC_REPLBUFF,
  66 };
  67
  68 /*
  69  * If requests are retransmitted within this interval, they're dropped.
  70  */
  71 #define RC_DELAY                (HZ/5)
  72
  73 int     nfsd_reply_cache_init(void);
  74 void    nfsd_reply_cache_shutdown(void);
  75 int     nfsd_cache_lookup(struct svc_rqst *, int);
  76 void    nfsd_cache_update(struct svc_rqst *, int, __be32 *);
  77
  78 #ifdef CONFIG_NFSD_V4
  79 void    nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp);
  80 #else  /* CONFIG_NFSD_V4 */
  81 static inline void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
  82 {
  83 }
  84 #endif /* CONFIG_NFSD_V4 */
  85
  86 #endif /* NFSCACHE_H */