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  */
  16 struct 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 */
  39 enum {
  40         RC_UNUSED,
  41         RC_INPROG,
  42         RC_DONE
  43 };
  44
  45 /* return values */
  46 enum {
  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  */
  59 enum {
  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
  70 int     nfsd_reply_cache_init(void);
  71 void    nfsd_reply_cache_shutdown(void);
  72 int     nfsd_cache_lookup(struct svc_rqst *, int);
  73 void    nfsd_cache_update(struct svc_rqst *, int, __be32 *);
  74
  75 #ifdef CONFIG_NFSD_V4
  76 void    nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp);
  77 #else  /* CONFIG_NFSD_V4 */
  78 static inline void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
  79 {
  80 }
  81 #endif /* CONFIG_NFSD_V4 */
  82
  83 #endif /* NFSCACHE_H */