cache.h

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/*
 * Request reply cache. This was heavily inspired by the
 * implementation in 4.3BSD/4.4BSD.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
 */

#ifndef NFSCACHE_H
#define NFSCACHE_H

#include <linux/sunrpc/svc.h>

/*
 * Representation of a reply cache entry.
 */
struct svc_cacherep {
    struct hlist_node   c_hash;
    struct list_head    c_lru;

    unsigned char       c_state,    /* unused, inprog, done */
                c_type,     /* status, buffer */
                c_secure : 1;   /* req came from port < 1024 */
    struct sockaddr_in  c_addr;
    __be32          c_xid;
    u32         c_prot;
    u32         c_proc;
    u32         c_vers;
    unsigned long       c_timestamp;
    union {
        struct kvec u_vec;
        __be32      u_status;
    }           c_u;
};

#define c_replvec       c_u.u_vec
#define c_replstat      c_u.u_status

/* cache entry states */
enum {
    RC_UNUSED,
    RC_INPROG,
    RC_DONE
};

/* return values */
enum {
    RC_DROPIT,
    RC_REPLY,
    RC_DOIT,
    RC_INTR
};

/*
 * Cache types.
 * We may want to add more types one day, e.g. for diropres and
 * attrstat replies. Using cache entries with fixed length instead
 * of buffer pointers may be more efficient.
 */
enum {
    RC_NOCACHE,
    RC_REPLSTAT,
    RC_REPLBUFF,
};

/*
 * If requests are retransmitted within this interval, they're dropped.
 */
#define RC_DELAY        (HZ/5)

int nfsd_reply_cache_init(void);
void    nfsd_reply_cache_shutdown(void);
int nfsd_cache_lookup(struct svc_rqst *);
void    nfsd_cache_update(struct svc_rqst *, int, __be32 *);

#ifdef CONFIG_NFSD_V4
void    nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp);
#else  /* CONFIG_NFSD_V4 */
static inline void nfsd4_set_statp(struct svc_rqst *rqstp, __be32 *statp)
{
}
#endif /* CONFIG_NFSD_V4 */

#endif /* NFSCACHE_H */