37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] =
"@(#)hash_buf.c 8.5 (Berkeley) 7/15/94";
57 #include <sys/param.h>
68 #include "../include/db.h"
76 #define BUF_REMOVE(B) { \
77 (B)->prev->next = (B)->next; \
78 (B)->next->prev = (B)->prev; \
82 #define BUF_INSERT(B, P) { \
83 (B)->next = (P)->next; \
86 (B)->next->prev = (B); \
89 #define MRU hashp->bufhead.next
90 #define LRU hashp->bufhead.prev
92 #define MRU_INSERT(B) BUF_INSERT((B), &hashp->bufhead)
93 #define LRU_INSERT(B) BUF_INSERT((B), LRU)
105 __get_buf(hashp, addr, prev_bp, newpage)
112 register u_int32_t is_disk_mask;
113 register int is_disk, segment_ndx = 0;
120 if (!bp || (bp->addr != addr))
126 segment_ndx = addr & (hashp->SGSIZE - 1);
129 segp = hashp->dir[addr >> hashp->SSHIFT];
131 assert(segp != NULL);
133 bp = PTROF(segp[segment_ndx]);
134 is_disk_mask = ISDISK(segp[segment_ndx]);
135 is_disk = is_disk_mask || !hashp->new_file;
139 bp = newbuf(hashp, addr, prev_bp);
141 __get_page(hashp, bp->page, addr, !prev_bp, is_disk, 0))
145 (
BUFHEAD *)((ptrdiff_t)bp | is_disk_mask);
160 newbuf(hashp, addr, prev_bp)
170 u_int16_t oaddr, *shortp;
178 if (hashp->nbufs || (bp->flags & BUF_PIN)) {
183 memset(bp, 0xff,
sizeof(
BUFHEAD));
185 if ((bp->page = (
char *)malloc(hashp->BSIZE)) == NULL) {
190 memset(bp->page, 0xff, hashp->BSIZE);
201 if ((bp->addr != 0) || (bp->flags & BUF_BUCKET)) {
206 shortp = (u_int16_t *)bp->page;
208 oaddr = shortp[shortp[0] - 1];
209 if ((bp->flags & BUF_MOD) && __put_page(hashp, bp->page,
210 bp->addr, (
int)IS_BUCKET(bp->flags), 0))
220 if (IS_BUCKET(bp->flags)) {
221 segment_ndx = bp->addr & (hashp->SGSIZE - 1);
222 segp = hashp->dir[bp->addr >> hashp->SSHIFT];
224 assert(segp != NULL);
227 if (hashp->new_file &&
228 ((bp->flags & BUF_MOD) ||
229 ISDISK(segp[segment_ndx])))
230 segp[segment_ndx] = (
BUFHEAD *)BUF_DISK;
232 segp[segment_ndx] = NULL;
239 for (xbp = bp; xbp->ovfl;) {
240 next_xbp = xbp->ovfl;
245 if (IS_BUCKET(xbp->flags) ||
246 (oaddr != xbp->addr))
249 shortp = (u_int16_t *)xbp->page;
252 oaddr = shortp[shortp[0] - 1];
253 if ((xbp->flags & BUF_MOD) && __put_page(hashp,
254 xbp->page, xbp->addr, 0, 0))
267 (void)fprintf(stderr,
"NEWBUF1: %d->ovfl was %d is now %d\n",
268 bp->addr, (bp->ovfl ? bp->ovfl->addr : 0), 0);
277 (void)fprintf(stderr,
"NEWBUF2: %d->ovfl was %d is now %d\n",
278 prev_bp->addr, (prev_bp->ovfl ? bp->ovfl->addr : 0),
279 (bp ? bp->addr : 0));
284 bp->flags = BUF_BUCKET;
290 __buf_init(hashp, nbytes)
297 bfp = &(hashp->bufhead);
298 npages = (nbytes + hashp->BSIZE - 1) >> hashp->BSHIFT;
299 npages = MAX(npages, MIN_BUFFERS);
301 hashp->nbufs = npages;
315 __buf_free(hashp, do_free, to_disk)
317 int do_free, to_disk;
324 for (bp = LRU; bp != &hashp->bufhead;) {
326 if (bp->addr || IS_BUCKET(bp->flags)) {
327 if (to_disk && (bp->flags & BUF_MOD) &&
328 __put_page(hashp, bp->page,
329 bp->addr, IS_BUCKET(bp->flags), 0))
346 __reclaim_buf(hashp, bp)