diff options
Diffstat (limited to 'db/hash/hash_buf.c')
| -rw-r--r-- | db/hash/hash_buf.c | 355 |
1 files changed, 0 insertions, 355 deletions
diff --git a/db/hash/hash_buf.c b/db/hash/hash_buf.c deleted file mode 100644 index 92e1f933ad..0000000000 --- a/db/hash/hash_buf.c +++ /dev/null @@ -1,355 +0,0 @@ -/*- - * 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. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by the University of - * California, Berkeley and its contributors. - * 4. 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. - */ - -#if defined(LIBC_SCCS) && !defined(lint) -static char sccsid[] = "@(#)hash_buf.c 8.5 (Berkeley) 7/15/94"; -#endif /* LIBC_SCCS and not lint */ - -/* - * PACKAGE: hash - * - * DESCRIPTION: - * Contains buffer management - * - * ROUTINES: - * External - * __buf_init - * __get_buf - * __buf_free - * __reclaim_buf - * Internal - * newbuf - */ - -#include <sys/param.h> - -#include <errno.h> -#include <stddef.h> -#include <stdio.h> -#include <stdlib.h> - -#ifdef DEBUG -#include <assert.h> -#endif - -#include <db.h> -#include "hash.h" -#include "page.h" -#include "extern.h" - -static BUFHEAD *newbuf __P((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. - */ -extern BUFHEAD * -__get_buf(hashp, addr, prev_bp, newpage) - HTAB *hashp; - u_int32_t addr; - BUFHEAD *prev_bp; - int newpage; /* If prev_bp set, indicates a new overflow page. */ -{ - register BUFHEAD *bp; - register u_int32_t is_disk_mask; - register int is_disk, segment_ndx; - SEGMENT segp; - - is_disk = 0; - is_disk_mask = 0; - 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(hashp, addr, prev_bp) - HTAB *hashp; - u_int32_t addr; - BUFHEAD *prev_bp; -{ - register BUFHEAD *bp; /* The buffer we're going to use */ - register BUFHEAD *xbp; /* Temp pointer */ - register 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 *)malloc(sizeof(BUFHEAD))) == NULL) - return (NULL); -#ifdef PURIFY - memset(bp, 0xff, sizeof(BUFHEAD)); -#endif - if ((bp->page = (char *)malloc(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 - (void)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 - (void)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(hashp, nbytes) - 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(hashp, do_free, to_disk) - HTAB *hashp; - int do_free, 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) - free(bp->page); - BUF_REMOVE(bp); - free(bp); - bp = LRU; - } else - bp = bp->prev; - } - return (0); -} - -extern void -__reclaim_buf(hashp, bp) - HTAB *hashp; - BUFHEAD *bp; -{ - bp->ovfl = 0; - bp->addr = 0; - bp->flags = 0; - BUF_REMOVE(bp); - LRU_INSERT(bp); -} |