Import sources from 2011-03-30 iso image

1 files changed, 316 insertions, 0 deletions

diff --git a/sys/src/cmd/dossrv/iotrack.c b/sys/src/cmd/dossrv/iotrack.c
new file mode 100755
index 000000000..2815fa8c7
--- /dev/null
+++ b/sys/src/cmd/dossrv/iotrack.c
@@ -0,0 +1,316 @@
+#include <u.h>
+#include <libc.h>
+#include "iotrack.h"
+#include "dat.h"
+#include "fns.h"
+
+#define	HIOB		31	/* a prime */
+#define	NIOBUF		80
+
+static Iotrack	hiob[HIOB+1];		/* hash buckets + lru list */
+static Iotrack	iobuf[NIOBUF];		/* the real ones */
+
+#define	UNLINK(p, nx, pr)	((p)->pr->nx = (p)->nx, (p)->nx->pr = (p)->pr)
+
+#define	LINK(h, p, nx, pr)	((p)->nx = (h)->nx, (p)->pr = (h), \
+				 (h)->nx->pr = (p), (h)->nx = (p))
+
+#define	HTOFRONT(h, p)	((h)->hnext != (p) && (UNLINK(p,hnext,hprev), LINK(h,p,hnext,hprev)))
+
+#define	TOFRONT(h, p)	((h)->next  != (p) && (UNLINK(p, next, prev), LINK(h,p, next, prev)))
+
+Iosect *
+getsect(Xfs *xf, long addr)
+{
+	return getiosect(xf, addr, 1);
+}
+
+Iosect *
+getosect(Xfs *xf, long addr)
+{
+	return getiosect(xf, addr, 0);
+}
+
+Iosect *
+getiosect(Xfs *xf, long addr, int rflag)
+{
+	Iotrack *t;
+	long taddr;
+	int toff;
+	Iosect *p;
+
+	toff = addr % Sect2trk;
+	taddr = addr - toff;
+	t = getiotrack(xf, taddr);
+	if(rflag && (t->flags&BSTALE)){
+		if(tread(t) < 0){
+			unmlock(&t->lock);
+			return 0;
+		}
+		t->flags &= ~BSTALE;
+	}
+	t->ref++;
+	p = t->tp->p[toff];
+	if(p == 0){
+		p = newsect();
+		t->tp->p[toff] = p;
+		p->flags = t->flags&BSTALE;
+		p->lock.key = 0;
+		p->t = t;
+		p->iobuf = t->tp->buf[toff];
+	}
+	unmlock(&t->lock);
+	mlock(&p->lock);
+	return p;
+}
+
+void
+putsect(Iosect *p)
+{
+	Iotrack *t;
+
+	if(canmlock(&p->lock))
+		panic("putsect");
+	t = p->t;
+	mlock(&t->lock);
+	t->flags |= p->flags;
+	p->flags = 0;
+	t->ref--;
+	if(t->flags & BIMM){
+		if(t->flags & BMOD)
+			twrite(t);
+		t->flags &= ~(BMOD|BIMM);
+	}
+	unmlock(&t->lock);
+	unmlock(&p->lock);
+}
+
+Iotrack *
+getiotrack(Xfs *xf, long addr)
+{
+	Iotrack *hp, *p;
+	Iotrack *mp = &hiob[HIOB];
+	long h;
+/*
+ *	chat("iotrack %d,%d...", dev, addr);
+ */
+	h = (xf->dev<<24) ^ addr;
+	if(h < 0)
+		h = ~h;
+	h %= HIOB;
+	hp = &hiob[h];
+
+loop:
+
+/*
+ * look for it in the active list
+ */
+	mlock(&hp->lock);
+	for(p=hp->hnext; p != hp; p=p->hnext){
+		if(p->addr != addr || p->xf != xf)
+			continue;
+		unmlock(&hp->lock);
+		mlock(&p->lock);
+		if(p->addr == addr && p->xf == xf)
+			goto out;
+		unmlock(&p->lock);
+		goto loop;
+	}
+	unmlock(&hp->lock);
+/*
+ * not found
+ * take oldest unref'd entry
+ */
+	mlock(&mp->lock);
+	for(p=mp->prev; p != mp; p=p->prev)
+		if(p->ref == 0 && canmlock(&p->lock)){
+			if(p->ref == 0)
+				break;
+			unmlock(&p->lock);
+		}
+	unmlock(&mp->lock);
+	if(p == mp){
+		print("iotrack all ref'd\n");
+		goto loop;
+	}
+	if(p->flags & BMOD){
+		twrite(p);
+		p->flags &= ~(BMOD|BIMM);
+		unmlock(&p->lock);
+		goto loop;
+	}
+	purgetrack(p);
+	p->addr = addr;
+	p->xf = xf;
+	p->flags = BSTALE;
+out:
+	mlock(&hp->lock);
+	HTOFRONT(hp, p);
+	unmlock(&hp->lock);
+	mlock(&mp->lock);
+	TOFRONT(mp, p);
+	unmlock(&mp->lock);
+	return p;
+}
+
+void
+purgetrack(Iotrack *t)
+{
+	int i, ref = Sect2trk;
+	Iosect *p;
+
+	for(i=0; i<Sect2trk; i++){
+		p = t->tp->p[i];
+		if(p == 0){
+			--ref;
+			continue;
+		}
+		if(canmlock(&p->lock)){
+			freesect(p);
+			--ref;
+			t->tp->p[i] = 0;
+		}
+	}
+	if(t->ref != ref)
+		panic("purgetrack");
+}
+
+int
+twrite(Iotrack *t)
+{
+	int i, ref;
+
+	chat("[twrite %ld...", t->addr);
+	if(t->flags & BSTALE){
+		for(ref=0,i=0; i<Sect2trk; i++)
+			if(t->tp->p[i])
+				++ref;
+		if(ref < Sect2trk){
+			if(tread(t) < 0){
+				chat("error]");
+				return -1;
+			}
+		}else
+			t->flags &= ~BSTALE;
+	}
+	if(devwrite(t->xf, t->addr, t->tp->buf, Trksize) < 0){
+		chat("error]");
+		return -1;
+	}
+	chat(" done]");
+	return 0;
+}
+
+int
+tread(Iotrack *t)
+{
+	int i, ref = 0;
+	uchar buf[Sect2trk][Sectorsize];
+
+	for(i=0; i<Sect2trk; i++)
+		if(t->tp->p[i])
+			++ref;
+	chat("[tread %ld+%ld...", t->addr, t->xf->offset);
+	if(ref == 0){
+		if(devread(t->xf, t->addr, t->tp->buf, Trksize) < 0){
+			chat("error]");
+			return -1;
+		}
+		chat("done]");
+		t->flags &= ~BSTALE;
+		return 0;
+	}
+	if(devread(t->xf, t->addr, buf, Trksize) < 0){
+		chat("error]");
+		return -1;
+	}
+	for(i=0; i<Sect2trk; i++)
+		if(t->tp->p[i] == 0){
+			memmove(t->tp->buf[i], buf[i], Sectorsize);
+			chat("%d ", i);
+		}
+	chat("done]");
+	t->flags &= ~BSTALE;
+	return 0;
+}
+
+void
+purgebuf(Xfs *xf)
+{
+	Iotrack *p;
+
+	for(p=&iobuf[0]; p<&iobuf[NIOBUF]; p++){
+		if(p->xf != xf)
+			continue;
+		mlock(&p->lock);
+		if(p->xf == xf){
+			if(p->flags & BMOD)
+				twrite(p);
+			p->flags = BSTALE;
+			purgetrack(p);
+		}
+		unmlock(&p->lock);
+	}
+}
+
+void
+sync(void)
+{
+	Iotrack *p;
+
+	for(p=&iobuf[0]; p<&iobuf[NIOBUF]; p++){
+		if(!(p->flags & BMOD))
+			continue;
+		mlock(&p->lock);
+		if(p->flags & BMOD){
+			twrite(p);
+			p->flags &= ~(BMOD|BIMM);
+		}
+		unmlock(&p->lock);
+	}
+}
+
+void
+iotrack_init(void)
+{
+	Iotrack *mp, *p;
+
+	for (mp=&hiob[0]; mp<&hiob[HIOB]; mp++)
+		mp->hprev = mp->hnext = mp;
+	mp->prev = mp->next = mp;
+
+	for (p=&iobuf[0]; p<&iobuf[NIOBUF]; p++) {
+		p->hprev = p->hnext = p;
+		p->prev = p->next = p;
+		TOFRONT(mp, p);
+		p->tp = sbrk(sizeof(Track));
+		memset(p->tp->p, 0, sizeof p->tp->p);
+	}
+}
+
+static MLock	freelock;
+static Iosect *	freelist;
+
+Iosect *
+newsect(void)
+{
+	Iosect *p;
+
+	mlock(&freelock);
+	if(p = freelist)	/* assign = */
+		freelist = p->next;
+	else
+		p = malloc(sizeof(Iosect));
+	unmlock(&freelock);
+	p->next = 0;
+	return p;
+}
+
+void
+freesect(Iosect *p)
+{
+	mlock(&freelock);
+	p->next = freelist;
+	freelist = p;
+	unmlock(&freelock);
+}