/*      $NetBSD: coda_namecache.h,v 1.12 2009/03/18 15:14:30 cegger Exp $       */

/*
 *
 *             Coda: an Experimental Distributed File System
 *                              Release 3.1
 *
 *           Copyright (c) 1987-1998 Carnegie Mellon University
 *                          All Rights Reserved
 *
 * Permission  to  use, copy, modify and distribute this software and its
 * documentation is hereby granted,  provided  that  both  the  copyright
 * notice  and  this  permission  notice  appear  in  all  copies  of the
 * software, derivative works or  modified  versions,  and  any  portions
 * thereof, and that both notices appear in supporting documentation, and
 * that credit is given to Carnegie Mellon University  in  all  documents
 * and publicity pertaining to direct or indirect use of this code or its
 * derivatives.
 *
 * CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS  KNOWN  TO  HAVE  BUGS,
 * SOME  OF  WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON ALLOWS
 * FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION.   CARNEGIE  MELLON
 * DISCLAIMS  ANY  LIABILITY  OF  ANY  KIND  FOR  ANY  DAMAGES WHATSOEVER
 * RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE  OR  OF
 * ANY DERIVATIVE WORK.
 *
 * Carnegie  Mellon  encourages  users  of  this  software  to return any
 * improvements or extensions that  they  make,  and  to  grant  Carnegie
 * Mellon the rights to redistribute these changes without encumbrance.
 *
 *      @(#) coda/coda_namecache.h,v 1.1.1.1 1998/08/29 21:26:46 rvb Exp $
 */

/*
 * Mach Operating System
 * Copyright (c) 1990 Carnegie-Mellon University
 * Copyright (c) 1989 Carnegie-Mellon University
 * All rights reserved.  The CMU software License Agreement specifies
 * the terms and conditions for use and redistribution.
 */

/*
 * This code was written for the Coda file system at Carnegie Mellon University.
 * Contributers include David Steere, James Kistler, and M. Satyanarayanan.
 */

#ifndef _CODA_NC_HEADER_
#define _CODA_NC_HEADER_

/*
 * Coda constants
 */
#define CODA_NC_NAMELEN         15              /* longest name stored in cache */
#define CODA_NC_CACHESIZE        256            /* Default cache size */
#define CODA_NC_HASHSIZE        64              /* Must be multiple of 2 */

/*
 * Hash function for the primary hash.
 */

/*
 * First try -- (first + last letters + length + (int)cp) mod size
 * 2nd try -- same, except dir fid.vnode instead of cp
 */

#ifdef  oldhash
#define CODA_NC_HASH(name, namelen, cp) \
        ((name[0] + name[namelen-1] + namelen + (int)(long)(cp)) \
          & (coda_nc_hashsize-1))
#else
#define CODA_NC_HASH(name, namelen, cp) \
        ((name[0] + (name[namelen-1]<<4) + namelen + (((int)(long)cp)>>8)) \
          & (coda_nc_hashsize-1))
#endif

#define CODA_NAMEMATCH(cp, name, namelen, dcp) \
        ((namelen == cp->namelen) && (dcp == cp->dcp) && \
                 (memcmp(cp->name,name,namelen) == 0))

#define CODA_NC_VALID(cncp)     (cncp->dcp != (struct cnode *)0)

#define DATA_PART(cncp) (&((cncp)->cp))
#define DATA_SIZE       (sizeof(struct coda_cache) - offsetof(struct coda_cache, cp))

/*
 * Structure for an element in the CODA Name Cache.
 */

struct coda_cache {
        LIST_ENTRY(coda_cache)  hash;           /* Hash list */
        TAILQ_ENTRY(coda_cache) lru;            /* LRU list */
        struct cnode    *cp;                    /* vnode of the file */
        struct cnode    *dcp;                   /* parent's cnode */
        kauth_cred_t    cred;                   /* user credentials */
        char            name[CODA_NC_NAMELEN];  /* segment name */
        int             namelen;                /* length of name */
};

struct  coda_lru {              /* Start of LRU chain */
        TAILQ_HEAD(,coda_cache) head;
};


struct coda_hash {              /* Start of Hash chain */
        LIST_HEAD(,coda_cache)  head;
        int                     length; /* used for tuning purposes */
};


/*
 * Symbols to aid in debugging the namecache code. Assumes the existence
 * of the variable coda_nc_debug, which is defined in cfs_namecache.c
 */
#define CODA_NC_DEBUG(N, STMT)     { if (coda_nc_debug & (1 <<N)) { STMT } }

/* Prototypes of functions exported within cfs */
extern void coda_nc_init(void);
extern void coda_nc_enter(struct cnode *, const char *, int,
    kauth_cred_t, struct cnode *);
extern struct cnode *coda_nc_lookup(struct cnode *, const char *, int, 
    kauth_cred_t);

extern void coda_nc_zapParentfid(CodaFid *, enum dc_status);
extern void coda_nc_zapfid(CodaFid *, enum dc_status);
extern void coda_nc_zapvnode(CodaFid *, kauth_cred_t, enum dc_status);
extern void coda_nc_zapfile(struct cnode *, const char *, int);
extern void coda_nc_purge_user(uid_t, enum dc_status);
extern void coda_nc_flush(enum dc_status);

extern void print_coda_nc(void);
extern void coda_nc_gather_stats(void);
extern int  coda_nc_resize(int, int, enum dc_status);
extern void coda_nc_name(struct cnode *cp);

/*
 * Structure to contain statistics on the cache usage
 */

struct coda_nc_statistics {
        unsigned        hits;
        unsigned        misses;
        unsigned        enters;
        unsigned        dbl_enters;
        unsigned        long_name_enters;
        unsigned        long_name_lookups;
        unsigned        long_remove;
        unsigned        lru_rm;
        unsigned        zapPfids;
        unsigned        zapFids;
        unsigned        zapFile;
        unsigned        zapUsers;
        unsigned        Flushes;
        unsigned        Sum_bucket_len;
        unsigned        Sum2_bucket_len;
        unsigned        Max_bucket_len;
        unsigned        Num_zero_len;
        unsigned        Search_len;
};

#define CODA_NC_FIND            ((u_long) 1)
#define CODA_NC_REMOVE          ((u_long) 2)
#define CODA_NC_INIT            ((u_long) 3)
#define CODA_NC_ENTER           ((u_long) 4)
#define CODA_NC_LOOKUP          ((u_long) 5)
#define CODA_NC_ZAPPFID         ((u_long) 6)
#define CODA_NC_ZAPFID          ((u_long) 7)
#define CODA_NC_ZAPVNODE                ((u_long) 8)
#define CODA_NC_ZAPFILE         ((u_long) 9)
#define CODA_NC_PURGEUSER               ((u_long) 10)
#define CODA_NC_FLUSH           ((u_long) 11)
#define CODA_NC_PRINTCODA_NC    ((u_long) 12)
#define CODA_NC_PRINTSTATS      ((u_long) 13)

#endif /* _CFSNC_HEADER_ */