[linux-2.6-block.git] / fs / nfsd / cache.h

/*
 * Request reply cache. This was heavily inspired by the
 * implementation in 4.3BSD/4.4BSD.
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
 */

#ifndef NFSCACHE_H
#define NFSCACHE_H

#include <linux/sunrpc/svc.h>

/*
 * Representation of a reply cache entry.
 *
 * Note that we use a sockaddr_in6 to hold the address instead of the more
 * typical sockaddr_storage. This is for space reasons, since sockaddr_storage
 * is much larger than a sockaddr_in6.
 */
struct svc_cacherep {
	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_in6	c_addr;
	__be32			c_xid;
	u32			c_prot;
	u32			c_proc;
	u32			c_vers;
	unsigned int		c_len;
	__wsum			c_csum;
	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
};

/*
 * 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)

/* Cache entries expire after this time period */
#define RC_EXPIRE		(120 * HZ)

/* Checksum this amount of the request */
#define RC_CSUMLEN		(256U)

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 *);
int	nfsd_reply_cache_stats_open(struct inode *, struct file *);

#endif /* NFSCACHE_H */
Commit	Line	Data
	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	* Note that we use a sockaddr_in6 to hold the address instead of the more
	17	* typical sockaddr_storage. This is for space reasons, since sockaddr_storage
	18	* is much larger than a sockaddr_in6.
	19	*/
	20	struct svc_cacherep {
	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_in6 c_addr;
	27	__be32 c_xid;
	28	u32 c_prot;
	29	u32 c_proc;
	30	u32 c_vers;
	31	unsigned int c_len;
	32	__wsum c_csum;
	33	unsigned long c_timestamp;
	34	union {
	35	struct kvec u_vec;
	36	__be32 u_status;
	37	} c_u;
	38	};
	39
	40	#define c_replvec c_u.u_vec
	41	#define c_replstat c_u.u_status
	42
	43	/* cache entry states */
	44	enum {
	45	RC_UNUSED,
	46	RC_INPROG,
	47	RC_DONE
	48	};
	49
	50	/* return values */
	51	enum {
	52	RC_DROPIT,
	53	RC_REPLY,
	54	RC_DOIT
	55	};
	56
	57	/*
	58	* Cache types.
	59	* We may want to add more types one day, e.g. for diropres and
	60	* attrstat replies. Using cache entries with fixed length instead
	61	* of buffer pointers may be more efficient.
	62	*/
	63	enum {
	64	RC_NOCACHE,
	65	RC_REPLSTAT,
	66	RC_REPLBUFF,
	67	};
	68
	69	/*
	70	* If requests are retransmitted within this interval, they're dropped.
	71	*/
	72	#define RC_DELAY (HZ/5)
	73
	74	/* Cache entries expire after this time period */
	75	#define RC_EXPIRE (120 * HZ)
	76
	77	/* Checksum this amount of the request */
	78	#define RC_CSUMLEN (256U)
	79
	80	int nfsd_reply_cache_init(void);
	81	void nfsd_reply_cache_shutdown(void);
	82	int nfsd_cache_lookup(struct svc_rqst *);
	83	void nfsd_cache_update(struct svc_rqst , int, __be32 );
	84	int nfsd_reply_cache_stats_open(struct inode , struct file );
	85
	86	#endif /* NFSCACHE_H */