[dragonfly.git] / lib / libc / db / hash / hash_buf.c

/*-
 * Copyright (c) 1990, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Margo Seltzer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/lib/libc/db/hash/hash_buf.c,v 1.4.8.1 2001/03/05 07:38:05 obrien Exp $
 * $DragonFly: src/lib/libc/db/hash/hash_buf.c,v 1.7 2005/11/19 20:46:32 swildner Exp $
 *
 * @(#)hash_buf.c	8.5 (Berkeley) 7/15/94
 */

/*
 * PACKAGE: hash
 *
 * DESCRIPTION:
 *	Contains buffer management
 *
 * ROUTINES:
 * External
 *	__buf_init
 *	__get_buf
 *	__buf_free
 *	__reclaim_buf
 * Internal
 *	newbuf
 */

#include <sys/param.h>

#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef DEBUG
#include <assert.h>
#endif

#include <db.h>
#include "hash.h"
#include "page.h"
#include "extern.h"

static BUFHEAD *newbuf (HTAB *, u_int32_t, BUFHEAD *);

/* Unlink B from its place in the lru */
#define BUF_REMOVE(B) { \
	(B)->prev->next = (B)->next; \
	(B)->next->prev = (B)->prev; \
}

/* Insert B after P */
#define BUF_INSERT(B, P) { \
	(B)->next = (P)->next; \
	(B)->prev = (P); \
	(P)->next = (B); \
	(B)->next->prev = (B); \
}

#define	MRU	hashp->bufhead.next
#define	LRU	hashp->bufhead.prev

#define MRU_INSERT(B)	BUF_INSERT((B), &hashp->bufhead)
#define LRU_INSERT(B)	BUF_INSERT((B), LRU)

/*
 * We are looking for a buffer with address "addr".  If prev_bp is NULL, then
 * address is a bucket index.  If prev_bp is not NULL, then it points to the
 * page previous to an overflow page that we are trying to find.
 *
 * CAVEAT:  The buffer header accessed via prev_bp's ovfl field may no longer
 * be valid.  Therefore, you must always verify that its address matches the
 * address you are seeking.
 *
 * Parameters:
 *	newpage:	If prev_bp set, indicates a new overflow page
 */
extern BUFHEAD *
__get_buf(HTAB *hashp, u_int32_t addr, BUFHEAD *prev_bp, int newpage)
{
	BUFHEAD *bp;
	u_int32_t is_disk_mask;
	int is_disk, segment_ndx;
	SEGMENT segp;

	is_disk = 0;
	is_disk_mask = 0;
	segment_ndx = 0;
	segp = NULL;
	if (prev_bp) {
		bp = prev_bp->ovfl;
		if (!bp || (bp->addr != addr))
			bp = NULL;
		if (!newpage)
			is_disk = BUF_DISK;
	} else {
		/* Grab buffer out of directory */
		segment_ndx = addr & (hashp->SGSIZE - 1);

		/* valid segment ensured by __call_hash() */
		segp = hashp->dir[addr >> hashp->SSHIFT];
#ifdef DEBUG
		assert(segp != NULL);
#endif
		bp = PTROF(segp[segment_ndx]);
		is_disk_mask = ISDISK(segp[segment_ndx]);
		is_disk = is_disk_mask || !hashp->new_file;
	}

	if (!bp) {
		bp = newbuf(hashp, addr, prev_bp);
		if (!bp ||
		    __get_page(hashp, bp->page, addr, !prev_bp, is_disk, 0))
			return (NULL);
		if (!prev_bp)
			segp[segment_ndx] =
			    (BUFHEAD *)((ptrdiff_t)bp | is_disk_mask);
	} else {
		BUF_REMOVE(bp);
		MRU_INSERT(bp);
	}
	return (bp);
}

/*
 * We need a buffer for this page. Either allocate one, or evict a resident
 * one (if we have as many buffers as we're allowed) and put this one in.
 *
 * If newbuf finds an error (returning NULL), it also sets errno.
 */
static BUFHEAD *
newbuf(HTAB *hashp, u_int32_t addr, BUFHEAD *prev_bp)
{
	BUFHEAD *bp;		/* The buffer we're going to use */
	BUFHEAD *xbp;		/* Temp pointer */
	BUFHEAD *next_xbp;
	SEGMENT segp;
	int segment_ndx;
	u_int16_t oaddr, *shortp;

	oaddr = 0;
	bp = LRU;
	/*
	 * If LRU buffer is pinned, the buffer pool is too small. We need to
	 * allocate more buffers.
	 */
	if (hashp->nbufs || (bp->flags & BUF_PIN)) {
		/* Allocate a new one */
		if ((bp = (BUFHEAD *)calloc(1, sizeof(BUFHEAD))) == NULL)
			return (NULL);
#ifdef PURIFY
		memset(bp, 0xff, sizeof(BUFHEAD));
#endif
		if ((bp->page = (char *)calloc(1, hashp->BSIZE)) == NULL) {
			free(bp);
			return (NULL);
		}
#ifdef PURIFY
		memset(bp->page, 0xff, hashp->BSIZE);
#endif
		if (hashp->nbufs)
			hashp->nbufs--;
	} else {
		/* Kick someone out */
		BUF_REMOVE(bp);
		/*
		 * If this is an overflow page with addr 0, it's already been
		 * flushed back in an overflow chain and initialized.
		 */
		if ((bp->addr != 0) || (bp->flags & BUF_BUCKET)) {
			/*
			 * Set oaddr before __put_page so that you get it
			 * before bytes are swapped.
			 */
			shortp = (u_int16_t *)bp->page;
			if (shortp[0])
				oaddr = shortp[shortp[0] - 1];
			if ((bp->flags & BUF_MOD) && __put_page(hashp, bp->page,
			    bp->addr, (int)IS_BUCKET(bp->flags), 0))
				return (NULL);
			/*
			 * Update the pointer to this page (i.e. invalidate it).
			 *
			 * If this is a new file (i.e. we created it at open
			 * time), make sure that we mark pages which have been
			 * written to disk so we retrieve them from disk later,
			 * rather than allocating new pages.
			 */
			if (IS_BUCKET(bp->flags)) {
				segment_ndx = bp->addr & (hashp->SGSIZE - 1);
				segp = hashp->dir[bp->addr >> hashp->SSHIFT];
#ifdef DEBUG
				assert(segp != NULL);
#endif

				if (hashp->new_file &&
				    ((bp->flags & BUF_MOD) ||
				    ISDISK(segp[segment_ndx])))
					segp[segment_ndx] = (BUFHEAD *)BUF_DISK;
				else
					segp[segment_ndx] = NULL;
			}
			/*
			 * Since overflow pages can only be access by means of
			 * their bucket, free overflow pages associated with
			 * this bucket.
			 */
			for (xbp = bp; xbp->ovfl;) {
				next_xbp = xbp->ovfl;
				xbp->ovfl = 0;
				xbp = next_xbp;

				/* Check that ovfl pointer is up date. */
				if (IS_BUCKET(xbp->flags) ||
				    (oaddr != xbp->addr))
					break;

				shortp = (u_int16_t *)xbp->page;
				if (shortp[0])
					/* set before __put_page */
					oaddr = shortp[shortp[0] - 1];
				if ((xbp->flags & BUF_MOD) && __put_page(hashp,
				    xbp->page, xbp->addr, 0, 0))
					return (NULL);
				xbp->addr = 0;
				xbp->flags = 0;
				BUF_REMOVE(xbp);
				LRU_INSERT(xbp);
			}
		}
	}

	/* Now assign this buffer */
	bp->addr = addr;
#ifdef DEBUG1
	fprintf(stderr, "NEWBUF1: %d->ovfl was %d is now %d\n",
	    bp->addr, (bp->ovfl ? bp->ovfl->addr : 0), 0);
#endif
	bp->ovfl = NULL;
	if (prev_bp) {
		/*
		 * If prev_bp is set, this is an overflow page, hook it in to
		 * the buffer overflow links.
		 */
#ifdef DEBUG1
		fprintf(stderr, "NEWBUF2: %d->ovfl was %d is now %d\n",
		    prev_bp->addr, (prev_bp->ovfl ? bp->ovfl->addr : 0),
		    (bp ? bp->addr : 0));
#endif
		prev_bp->ovfl = bp;
		bp->flags = 0;
	} else
		bp->flags = BUF_BUCKET;
	MRU_INSERT(bp);
	return (bp);
}

extern void
__buf_init(HTAB *hashp, int nbytes)
{
	BUFHEAD *bfp;
	int npages;

	bfp = &(hashp->bufhead);
	npages = (nbytes + hashp->BSIZE - 1) >> hashp->BSHIFT;
	npages = MAX(npages, MIN_BUFFERS);

	hashp->nbufs = npages;
	bfp->next = bfp;
	bfp->prev = bfp;
	/*
	 * This space is calloc'd so these are already null.
	 *
	 * bfp->ovfl = NULL;
	 * bfp->flags = 0;
	 * bfp->page = NULL;
	 * bfp->addr = 0;
	 */
}

extern int
__buf_free(HTAB *hashp, int do_free, int to_disk)
{
	BUFHEAD *bp;

	/* Need to make sure that buffer manager has been initialized */
	if (!LRU)
		return (0);
	for (bp = LRU; bp != &hashp->bufhead;) {
		/* Check that the buffer is valid */
		if (bp->addr || IS_BUCKET(bp->flags)) {
			if (to_disk && (bp->flags & BUF_MOD) &&
			    __put_page(hashp, bp->page,
			    bp->addr, IS_BUCKET(bp->flags), 0))
				return (-1);
		}
		/* Check if we are freeing stuff */
		if (do_free) {
			if (bp->page) {
				memset(bp->page, 0, hashp->BSIZE);
				free(bp->page);
			}
			BUF_REMOVE(bp);
			free(bp);
			bp = LRU;
		} else
			bp = bp->prev;
	}
	return (0);
}

extern void
__reclaim_buf(HTAB *hashp, BUFHEAD *bp)
{
	bp->ovfl = 0;
	bp->addr = 0;
	bp->flags = 0;
	BUF_REMOVE(bp);
	LRU_INSERT(bp);
}
Commit	Line	Data
984263bc MD	1	/*-
	2	* Copyright (c) 1990, 1993, 1994
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* Margo Seltzer.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
cbebfd39	16	* 3. Neither the name of the University nor the names of its contributors
984263bc MD	17	* may be used to endorse or promote products derived from this software
	18	* without specific prior written permission.
	19	*
	20	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	* SUCH DAMAGE.
	31	*
	32	* $FreeBSD: src/lib/libc/db/hash/hash_buf.c,v 1.4.8.1 2001/03/05 07:38:05 obrien Exp $
17d47efc	33	* $DragonFly: src/lib/libc/db/hash/hash_buf.c,v 1.7 2005/11/19 20:46:32 swildner Exp $
1de703da MD	34	*
1de703da MD	35	* @(#)hash_buf.c 8.5 (Berkeley) 7/15/94
984263bc	36	*/
984263bc MD	37
	38	/*
	39	* PACKAGE: hash
	40	*
	41	* DESCRIPTION:
	42	* Contains buffer management
	43	*
	44	* ROUTINES:
	45	* External
	46	* __buf_init
	47	* __get_buf
	48	* __buf_free
	49	* __reclaim_buf
	50	* Internal
	51	* newbuf
	52	*/
	53
	54	#include <sys/param.h>
	55
	56	#include <stddef.h>
	57	#include <stdio.h>
	58	#include <stdlib.h>
7895edcd	59	#include <string.h>
984263bc MD	60
	61	#ifdef DEBUG
	62	#include <assert.h>
	63	#endif
	64
	65	#include <db.h>
	66	#include "hash.h"
	67	#include "page.h"
	68	#include "extern.h"
	69
064e1fb3	70	static BUFHEAD newbuf (HTAB , u_int32_t, BUFHEAD *);
984263bc MD	71
	72	/* Unlink B from its place in the lru */
	73	#define BUF_REMOVE(B) { \
	74	(B)->prev->next = (B)->next; \
	75	(B)->next->prev = (B)->prev; \
	76	}
	77
	78	/* Insert B after P */
	79	#define BUF_INSERT(B, P) { \
	80	(B)->next = (P)->next; \
	81	(B)->prev = (P); \
	82	(P)->next = (B); \
	83	(B)->next->prev = (B); \
	84	}
	85
	86	#define MRU hashp->bufhead.next
	87	#define LRU hashp->bufhead.prev
	88
	89	#define MRU_INSERT(B) BUF_INSERT((B), &hashp->bufhead)
	90	#define LRU_INSERT(B) BUF_INSERT((B), LRU)
	91
	92	/*
	93	* We are looking for a buffer with address "addr". If prev_bp is NULL, then
	94	* address is a bucket index. If prev_bp is not NULL, then it points to the
	95	* page previous to an overflow page that we are trying to find.
	96	*
	97	* CAVEAT: The buffer header accessed via prev_bp's ovfl field may no longer
	98	* be valid. Therefore, you must always verify that its address matches the
	99	* address you are seeking.
17d47efc SW	100	*
	101	* Parameters:
	102	* newpage: If prev_bp set, indicates a new overflow page
984263bc MD	103	*/
984263bc MD	104	extern BUFHEAD *
17d47efc	105	__get_buf(HTAB hashp, u_int32_t addr, BUFHEAD prev_bp, int newpage)
984263bc	106	{
660c873b DR	107	BUFHEAD *bp;
	108	u_int32_t is_disk_mask;
	109	int is_disk, segment_ndx;
984263bc MD	110	SEGMENT segp;
	111
	112	is_disk = 0;
	113	is_disk_mask = 0;
17d47efc SW	114	segment_ndx = 0;
17d47efc SW	115	segp = NULL;
984263bc MD	116	if (prev_bp) {
	117	bp = prev_bp->ovfl;
	118	if (!bp \|\| (bp->addr != addr))
	119	bp = NULL;
	120	if (!newpage)
	121	is_disk = BUF_DISK;
	122	} else {
	123	/* Grab buffer out of directory */
	124	segment_ndx = addr & (hashp->SGSIZE - 1);
	125
	126	/* valid segment ensured by __call_hash() */
	127	segp = hashp->dir[addr >> hashp->SSHIFT];
	128	#ifdef DEBUG
	129	assert(segp != NULL);
	130	#endif
	131	bp = PTROF(segp[segment_ndx]);
	132	is_disk_mask = ISDISK(segp[segment_ndx]);
	133	is_disk = is_disk_mask \|\| !hashp->new_file;
	134	}
	135
	136	if (!bp) {
	137	bp = newbuf(hashp, addr, prev_bp);
	138	if (!bp \|\|
	139	__get_page(hashp, bp->page, addr, !prev_bp, is_disk, 0))
	140	return (NULL);
	141	if (!prev_bp)
	142	segp[segment_ndx] =
	143	(BUFHEAD *)((ptrdiff_t)bp \| is_disk_mask);
	144	} else {
	145	BUF_REMOVE(bp);
	146	MRU_INSERT(bp);
	147	}
	148	return (bp);
	149	}
	150
	151	/*
	152	* We need a buffer for this page. Either allocate one, or evict a resident
	153	* one (if we have as many buffers as we're allowed) and put this one in.
	154	*
	155	* If newbuf finds an error (returning NULL), it also sets errno.
	156	*/
	157	static BUFHEAD *
c9fbf0d3	158	newbuf(HTAB hashp, u_int32_t addr, BUFHEAD prev_bp)
984263bc	159	{
660c873b DR	160	BUFHEAD bp; / The buffer we're going to use */
	161	BUFHEAD xbp; / Temp pointer */
	162	BUFHEAD *next_xbp;
984263bc MD	163	SEGMENT segp;
	164	int segment_ndx;
	165	u_int16_t oaddr, *shortp;
	166
	167	oaddr = 0;
	168	bp = LRU;
	169	/*
	170	* If LRU buffer is pinned, the buffer pool is too small. We need to
	171	* allocate more buffers.
	172	*/
	173	if (hashp->nbufs \|\| (bp->flags & BUF_PIN)) {
	174	/* Allocate a new one */
7895edcd	175	if ((bp = (BUFHEAD *)calloc(1, sizeof(BUFHEAD))) == NULL)
984263bc MD	176	return (NULL);
	177	#ifdef PURIFY
	178	memset(bp, 0xff, sizeof(BUFHEAD));
	179	#endif
7895edcd	180	if ((bp->page = (char *)calloc(1, hashp->BSIZE)) == NULL) {
984263bc MD	181	free(bp);
	182	return (NULL);
	183	}
	184	#ifdef PURIFY
	185	memset(bp->page, 0xff, hashp->BSIZE);
	186	#endif
	187	if (hashp->nbufs)
	188	hashp->nbufs--;
	189	} else {
	190	/* Kick someone out */
	191	BUF_REMOVE(bp);
	192	/*
	193	* If this is an overflow page with addr 0, it's already been
	194	* flushed back in an overflow chain and initialized.
	195	*/
	196	if ((bp->addr != 0) \|\| (bp->flags & BUF_BUCKET)) {
	197	/*
	198	* Set oaddr before __put_page so that you get it
	199	* before bytes are swapped.
	200	*/
	201	shortp = (u_int16_t *)bp->page;
	202	if (shortp[0])
	203	oaddr = shortp[shortp[0] - 1];
	204	if ((bp->flags & BUF_MOD) && __put_page(hashp, bp->page,
	205	bp->addr, (int)IS_BUCKET(bp->flags), 0))
	206	return (NULL);
	207	/*
	208	* Update the pointer to this page (i.e. invalidate it).
	209	*
	210	* If this is a new file (i.e. we created it at open
	211	* time), make sure that we mark pages which have been
	212	* written to disk so we retrieve them from disk later,
	213	* rather than allocating new pages.
	214	*/
	215	if (IS_BUCKET(bp->flags)) {
	216	segment_ndx = bp->addr & (hashp->SGSIZE - 1);
	217	segp = hashp->dir[bp->addr >> hashp->SSHIFT];
	218	#ifdef DEBUG
	219	assert(segp != NULL);
	220	#endif
	221
	222	if (hashp->new_file &&
	223	((bp->flags & BUF_MOD) \|\|
	224	ISDISK(segp[segment_ndx])))
	225	segp[segment_ndx] = (BUFHEAD *)BUF_DISK;
	226	else
	227	segp[segment_ndx] = NULL;
	228	}
	229	/*
	230	* Since overflow pages can only be access by means of
	231	* their bucket, free overflow pages associated with
	232	* this bucket.
	233	*/
	234	for (xbp = bp; xbp->ovfl;) {
	235	next_xbp = xbp->ovfl;
	236	xbp->ovfl = 0;
	237	xbp = next_xbp;
	238
	239	/* Check that ovfl pointer is up date. */
	240	if (IS_BUCKET(xbp->flags) \|\|
	241	(oaddr != xbp->addr))
	242	break;
	243
	244	shortp = (u_int16_t *)xbp->page;
245	if (shortp[0])
246	/* set before __put_page */
247	oaddr = shortp[shortp[0] - 1];
248	if ((xbp->flags & BUF_MOD) && __put_page(hashp,
249	xbp->page, xbp->addr, 0, 0))
250	return (NULL);
251	xbp->addr = 0;
252	xbp->flags = 0;
253	BUF_REMOVE(xbp);
254	LRU_INSERT(xbp);
255	}
256	}
257	}
258
259	/* Now assign this buffer */
260	bp->addr = addr;
261	#ifdef DEBUG1
c9fbf0d3	262	fprintf(stderr, "NEWBUF1: %d->ovfl was %d is now %d\n",
984263bc MD	263	bp->addr, (bp->ovfl ? bp->ovfl->addr : 0), 0);
	264	#endif
	265	bp->ovfl = NULL;
	266	if (prev_bp) {
	267	/*
	268	* If prev_bp is set, this is an overflow page, hook it in to
	269	* the buffer overflow links.
	270	*/
	271	#ifdef DEBUG1
c9fbf0d3	272	fprintf(stderr, "NEWBUF2: %d->ovfl was %d is now %d\n",
984263bc MD	273	prev_bp->addr, (prev_bp->ovfl ? bp->ovfl->addr : 0),
	274	(bp ? bp->addr : 0));
	275	#endif
	276	prev_bp->ovfl = bp;
	277	bp->flags = 0;
	278	} else
	279	bp->flags = BUF_BUCKET;
	280	MRU_INSERT(bp);
	281	return (bp);
	282	}
	283
	284	extern void
c9fbf0d3	285	__buf_init(HTAB *hashp, int nbytes)
984263bc MD	286	{
	287	BUFHEAD *bfp;
	288	int npages;
	289
	290	bfp = &(hashp->bufhead);
	291	npages = (nbytes + hashp->BSIZE - 1) >> hashp->BSHIFT;
	292	npages = MAX(npages, MIN_BUFFERS);
	293
	294	hashp->nbufs = npages;
	295	bfp->next = bfp;
	296	bfp->prev = bfp;
	297	/*
	298	* This space is calloc'd so these are already null.
	299	*
	300	* bfp->ovfl = NULL;
	301	* bfp->flags = 0;
	302	* bfp->page = NULL;
	303	* bfp->addr = 0;
	304	*/
	305	}
	306
	307	extern int
c9fbf0d3	308	__buf_free(HTAB *hashp, int do_free, int to_disk)
984263bc MD	309	{
	310	BUFHEAD *bp;
	311
	312	/* Need to make sure that buffer manager has been initialized */
	313	if (!LRU)
	314	return (0);
	315	for (bp = LRU; bp != &hashp->bufhead;) {
	316	/* Check that the buffer is valid */
	317	if (bp->addr \|\| IS_BUCKET(bp->flags)) {
	318	if (to_disk && (bp->flags & BUF_MOD) &&
	319	__put_page(hashp, bp->page,
	320	bp->addr, IS_BUCKET(bp->flags), 0))
	321	return (-1);
	322	}
	323	/* Check if we are freeing stuff */
	324	if (do_free) {
7895edcd MD	325	if (bp->page) {
7895edcd MD	326	memset(bp->page, 0, hashp->BSIZE);
984263bc	327	free(bp->page);
7895edcd	328	}
984263bc MD	329	BUF_REMOVE(bp);
	330	free(bp);
	331	bp = LRU;
	332	} else
	333	bp = bp->prev;
	334	}
	335	return (0);
	336	}
	337
	338	extern void
c9fbf0d3	339	__reclaim_buf(HTAB hashp, BUFHEAD bp)
984263bc MD	340	{
	341	bp->ovfl = 0;
	342	bp->addr = 0;
	343	bp->flags = 0;
	344	BUF_REMOVE(bp);
	345	LRU_INSERT(bp);
	346	}