1993/1014/port/cache.c (diff list | history)

1993/1013/sys/src/9/port/cache.c:8,19 – 1993/1014/sys/src/9/port/cache.c:8,27 (short | long | prev | next)
1993/1011
1993/1013		Image fscache; typedef Extent Extent;
1993/1014		enum { NHASH = 128, MAXCACHE = 1024*1024, NFILE = 4096, }; typedef struct Extent Extent;
1993/1013		struct Extent
1993/1011		{
1993/1013		int bid; ulong start; int len;
1993/1014		Page *cache;
1993/1013		Extent *next; };
1993/1013/sys/src/9/port/cache.c:23,29 – 1993/1014/sys/src/9/port/cache.c:31,37
1993/1011		Qid;
1993/1013		int dev; int type; Qlock;
1993/1014		QLock;
1993/1013		Extent *list; Mntcache *hash; Mntcache *prev;
1993/1013/sys/src/9/port/cache.c:40,55 – 1993/1014/sys/src/9/port/cache.c:48,85
1993/1011		};
1993/1013		Cache cache;
1993/1011
1993/1014		void cinit(void) { int i; Mntcache *m; cache.ref = 1; cache.head = xalloc(sizeof(Mntcache)*NFILE); m = cache.head; for(i = NFILE; i > 0; i++) { m->next = m+1; m->prev = m-1; m++; } cache.tail = m; cache.tail->next = 0; cache.head->prev = 0; }
1993/1013		Mntcache* clook(Chan *c)
1993/1011		{
1993/1013		int h;
1993/1014		Mntcache *m;
1993/1011
1993/1013		h = c->qid.path%NHASH; lock(&cache); for(m = cache.hash[h]; m; m = m->hash) { if(m->path == c->path) {
1993/1014		if(m->path == c->qid.path) {
1993/1013		qlock(m); if(m->path == c->qid.path) if(m->dev == c->dev)
1993/1013/sys/src/9/port/cache.c:65,70 – 1993/1014/sys/src/9/port/cache.c:95,122
1993/1013		} void
1993/1014		cprint(Mntcache *m) { Extent *e; print("%lux.%lux %d %d\n", m->path, m->vers, m->type, m->dev); while(e) print("\t%4d %5d %4d %lux\n", e->bid, e->start, e->len, e->cache); } Page* cpage(Extent *e) { /* Easy consistency check */ if(e->cache->daddr != e->bid) return 0; return lookpage(&fscache, e->bid); } void
1993/1013		cnodata(Mntcache *m) { Extent *e, *n;
1993/1013/sys/src/9/port/cache.c:74,80 – 1993/1014/sys/src/9/port/cache.c:126,132
1993/1013		* Image lru will waste the pages */ for(e = m->list; e; e = n) { n = e->list;
1993/1014		n = e->next;
1993/1013		free(e); } }
1993/1013/sys/src/9/port/cache.c:116,122 – 1993/1014/sys/src/9/port/cache.c:168,174
1993/1013		m = clook(c); if(m != 0) { /* File was updated */ if(m->vers != c->vers)
1993/1014		if(m->vers != c->qid.vers)
1993/1013		cnodata(m); ctail(m);
1993/1013/sys/src/9/port/cache.c:127,134 – 1993/1014/sys/src/9/port/cache.c:179,186
1993/1013		/* LRU the cache headers */ m = cache.head; qlock(m); lock(cache); l = &cache.hash[m->qid.path%NHASH];
1993/1014		lock(&cache); l = &cache.hash[m->path%NHASH];
1993/1013		for(f = *l; f; f = f->next) { if(f == m) { *l = f->next;
1993/1013/sys/src/9/port/cache.c:139,146 – 1993/1014/sys/src/9/port/cache.c:191,198
1993/1013		l = &cache.hash[c->qid.path%NHASH]; m->hash = *l; *l = m; unlock(cache); m->qid = c->qid;
1993/1014		unlock(&cache); m->Qid = c->qid;
1993/1013		m->dev = c->dev; m->type = c->type; cnodata(m);
1993/1013/sys/src/9/port/cache.c:152,160 – 1993/1014/sys/src/9/port/cache.c:204,212
1993/1013		static int cdev(Mntcache *m, Chan *c) { if(m->path != c->path)
1993/1014		if(m->path != c->qid.path)
1993/1013		return 0; if(m->vers != c->vers)
1993/1014		if(m->vers != c->qid.vers)
1993/1013		return 0; if(m->dev != c->dev) return 0;
1993/1013/sys/src/9/port/cache.c:164,176 – 1993/1014/sys/src/9/port/cache.c:216,228
1993/1013		} int cread(Chan *c, uchar *buf, int len, long offset)
1993/1014		cread(Chan *c, uchar *buf, int len, ulong offset)
1993/1013		{ KMap *k; Page *p; Mntcache *m; Extent *e, **l; int o, l, total;
1993/1014		Extent *e, **t; int o, l, total, end;
1993/1013		m = c->mcp; if(m == 0)
1993/1013/sys/src/9/port/cache.c:182,192 – 1993/1014/sys/src/9/port/cache.c:234,244
1993/1013		} end = offset+len; l = &m->list; for(e = *l; e; e = e->next) {
1993/1014		t = &m->list; for(e = *t; e; e = e->next) {
1993/1013		if(e->start >= offset && e->start+e->len < end) break; l = &e->next;
1993/1014		t = &e->next;
1993/1013		} if(e == 0) {
1993/1013/sys/src/9/port/cache.c:196,204 – 1993/1014/sys/src/9/port/cache.c:248,256
1993/1013		total = 0; while(len) { p = lookpage(&fscache, e->bid);
1993/1014		p = cpage(e);
1993/1013		if(p == 0) { *l = e->next;
1993/1014		*t = e->next;
1993/1013		free(e); qunlock(m); return total;
1993/1013/sys/src/9/port/cache.c:217,224 – 1993/1014/sys/src/9/port/cache.c:269,275
1993/1013		if(l > e->len-o) l = e->len-o; p = (uchar*)VA(k) + o; memset(buf, p, l);
1993/1014		memmove(buf, (uchar*)VA(k) + o, l);
1993/1013		kunmap(k); putpage(p);
1993/1013/sys/src/9/port/cache.c:226,245 – 1993/1014/sys/src/9/port/cache.c:277,361
1993/1013		len -= l; offset += l; total += l; l = &e->next;
1993/1014		t = &e->next;
1993/1013		e = e->next; if(e == 0 || e->start != offset) break; } qunlock(m)
1993/1014		qunlock(m);
1993/1013		return total; }
1993/1014		Extent* cchain(uchar *buf, ulong offset, int len, Extent **tail) { int l; Page *p; KMap *k; Extent *e, *start, **t; start = 0; t = &start; while(len) { e = malloc(sizeof(Extent)); if(e == 0) break; p = auxpage(); if(p == 0) { free(e); break; } e->cache = p; e->start = offset; l = len; if(l > BY2PG) l = BY2PG; e->bid = incref(&cache); p->daddr = e->bid; k = kmap(p); memmove((void*)VA(k), buf, l); kunmap(k); cachepage(p, &fscache); putpage(p); buf += l; offset += l; len -= l; *t = e; *tail = e; t = &e->next; } return start; } int cpgmove(Extent *e, uchar *buf, int boff, int len) { Page *p; KMap *k; p = cpage(e); if(p == 0) return 0; k = kmap(p); memmove((uchar*)VA(k)+boff, buf, len); kunmap(k); putpage(p); return 1; }
1993/1013		void cwrite(Chan *c, uchar *buf, int len, long offset)
1993/1014		cupdate(Chan *c, uchar *buf, int len, ulong offset)
1993/1013		{ Extent *e; Mntcache *m;
1993/1014		Extent *tail; Extent *e, *f, *p; int o, ee, eblock;
1993/1013		if(offset > MAXCACHE) return;
1993/1013/sys/src/9/port/cache.c:253,274 – 1993/1014/sys/src/9/port/cache.c:369,459
1993/1013		return; } if(m->list == 0) { e = malloc(sizeof(Extent)); if(e == 0)
1993/1014		/* * Find the insertion point */ p = 0; for(f = m->list; f; f = f->next) { if(f->start >= offset) break; p = f; } if(p == 0) { /* at the head */ eblock = offset+len; /* trim if there is a successor */ if(f != 0 && eblock >= f->start) { len -= (eblock - f->start); if(len <= 0) { qunlock(m); return; } } e = cchain(buf, offset, len, &tail); m->list = e; if(tail != 0) tail->next = f; qunlock(m); return; } /* trim to the predecessor */ ee = p->start+p->len; if(offset < ee) { o = ee - offset; len -= o; if(len <= 0) { qunlock(m);
1993/1013		return; e->start = offset; l = len; if(l > BY2PG) l = BY2PG; p = auxpage(); if(p == 0)
1993/1014		} buf += o; offset += o; } /* try and pack data into the predecessor */ if(offset == ee && p->len < BY2PG) { o = len; if(o > BY2PG - p->len) o = BY2PG - p->len; if(len <= 0) { qunlock(m);
1993/1013		return; e->bid = incref(&cache); p->daddr = e->bid; cachepage(p, fscache); k = kmap(p);                  kunmap(p);
1993/1014		} if(cpgmove(e, buf, p->len, o)) { e->len += o; buf += o; len -= o; offset += o; if(len <= 0) { qunlock(m); return; } }
1993/1013		}
1993/1014		/* append to extent list */ if(f == 0) { p->next = cchain(buf, offset, len, &tail); qunlock(m); return; } /* trim data against successor */ eblock = offset+len; if(eblock > f->start) { o = eblock - f->start; if(o < 0) { qunlock(m); return; } len -= o; } /* Insert a middle block */ p->next = cchain(buf, offset, len, &tail); if(p->next == 0) p->next = f; else tail->next = f; qunlock(m);
1993/1011		}