From c2555390a7adf239b7bf436567e1e8d330473daf Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Tue, 22 Sep 1998 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1998-09-22

---
 pc/devata.c    |  9 +++++----
 port/qio.c     | 33 ++++++++++++++++++++++-----------
 port/sysfile.c | 23 ++++++++++++++++++-----
 3 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/pc/devata.c b/pc/devata.c
index 71734a4274b47d85e13069f0bd66b594452dc840..57d0a413201b4c149fb0c0e0c5c1b2e1c9dd4d27 100644
--- a/pc/devata.c
+++ b/pc/devata.c
@@ -1825,7 +1825,8 @@ atapiexec(Drive *dp)
 		nexterror();
 
 	if(cp->status & Serr){
-		DPRINT("%s: Bad packet command %ux, error %ux\n", dp->vol, cp->cmdblk[0], cp->error);
+		DPRINT("%s: Bad packet command 0x%ux, error 0x%ux\n",
+			dp->vol, cp->cmdblk[0], cp->error);
 		error(Eio);
 	}
 }
@@ -1985,7 +1986,7 @@ atapipart(Drive *dp)
 	retrycount = 2;
 retry:
 	if(waserror()){
-		DPRINT("atapipart: cmd %uX error %uX\n", cp->cmdblk[0], cp->error);
+		DPRINT("atapipart: cmd 0x%uX error 0x%uX\n", cp->cmdblk[0], cp->error);
 		if((cp->status & Serr) && (cp->error & 0xF0) == 0x60){
 			dp->vers++;
 			if(retrycount){
@@ -2015,7 +2016,7 @@ retry:
 	cp->cmdblk[4] = 18;
 	atapiexec(dp);
 	if(cp->count != 18){
-		print("cmd=%2.2uX, lastcmd=%2.2uX ", cp->cmd, cp->lastcmd);
+		print("cmd=0x%2.2uX, lastcmd=0x%2.2uX ", cp->cmd, cp->lastcmd);
 		print("cdsize count %d, status 0x%2.2uX, error 0x%2.2uX\n",
 			cp->count, cp->status, cp->error);
 		error(Eio);
@@ -2027,7 +2028,7 @@ retry:
 	cp->cmdblk[0] = Ccapacity;
 	atapiexec(dp);
 	if(cp->count != 8){
-		print("cmd=%2.2uX, lastcmd=%2.2uX ", cp->cmd, cp->lastcmd);
+		print("cmd=0x%2.2uX, lastcmd=0x%2.2uX ", cp->cmd, cp->lastcmd);
 		print("cdsize count %d, status 0x%2.2uX, error 0x%2.2uX\n",
 			cp->count, cp->status, cp->error);
 		error(Eio);
diff --git a/port/qio.c b/port/qio.c
index 0a5207d334ae2f5c12cc5ef9a67ca56a2ae8ecca..390f7546ddcd84a0f953dc90cfa668c991f51704 100644
--- a/port/qio.c
+++ b/port/qio.c
@@ -35,7 +35,8 @@ struct Queue
 	Block*	bfirst;		/* buffer */
 	Block*	blast;
 
-	int	len;		/* bytes in queue */
+	int	len;		/* bytes allocated to queue */
+	int	dlen;		/* data bytes in queue */
 	int	limit;		/* max bytes in queue */
 	int	inilim;		/* initial limit */
 	int	state;
@@ -531,6 +532,7 @@ qget(Queue *q)
 	q->bfirst = b->next;
 	b->next = 0;
 	q->len -= BALLOC(b);
+	q->dlen -= BLEN(b);
 	QDEBUG checkb(b, "qget");
 
 	/* if writer flow controlled, restart */
@@ -568,10 +570,12 @@ qdiscard(Queue *q, int len)
 			q->bfirst = b->next;
 			b->next = 0;
 			q->len -= BALLOC(b);
+			q->dlen -= BLEN(b);
 			freeb(b);
 		} else {
 			n = len - sofar;
 			b->rp += n;
+			q->dlen -= n;
 		}
 	}
 
@@ -625,6 +629,7 @@ qconsume(Queue *q, void *vp, int len)
 	if((q->state & Qmsg) || len == n)
 		q->bfirst = b->next;
 	b->rp += len;
+	q->dlen -= len;
 
 	/* if writer flow controlled, restart */
 	if((q->state & Qflow) && q->len < q->limit/2){
@@ -643,6 +648,7 @@ qconsume(Queue *q, void *vp, int len)
 	if((q->state & Qmsg) || len == n){
 		b->next = 0;
 		q->len -= BALLOC(b);
+		q->dlen -= BLEN(b);
 		freeb(b);
 	}
 	return len;
@@ -651,7 +657,7 @@ qconsume(Queue *q, void *vp, int len)
 int
 qpass(Queue *q, Block *b)
 {
-	int len, dowakeup;
+	int dlen, len, dowakeup;
 
 	/* sync with qread */
 	dowakeup = 0;
@@ -668,14 +674,17 @@ qpass(Queue *q, Block *b)
 	else
 		q->bfirst = b;
 	len = BALLOC(b);
+	dlen = BLEN(b);
 	QDEBUG checkb(b, "qpass");
 	while(b->next){
 		b = b->next;
 		QDEBUG checkb(b, "qpass");
 		len += BALLOC(b);
+		dlen += BLEN(b);
 	}
 	q->blast = b;
 	q->len += len;
+	q->dlen += dlen;
 
 	if(q->len >= q->limit/2)
 		q->state |= Qflow;
@@ -696,7 +705,7 @@ checkqlen(q);
 int
 qpassnolim(Queue *q, Block *b)
 {
-	int len, dowakeup;
+	int dlen, len, dowakeup;
 
 	/* sync with qread */
 	dowakeup = 0;
@@ -708,14 +717,17 @@ qpassnolim(Queue *q, Block *b)
 	else
 		q->bfirst = b;
 	len = BALLOC(b);
+	dlen = BLEN(b);
 	QDEBUG checkb(b, "qpass");
 	while(b->next){
 		b = b->next;
 		QDEBUG checkb(b, "qpass");
 		len += BALLOC(b);
+		dlen += BLEN(b);
 	}
 	q->blast = b;
 	q->len += len;
+	q->dlen += dlen;
 
 	if(q->len >= q->limit/2)
 		q->state |= Qflow;
@@ -792,6 +804,7 @@ qproduce(Queue *q, void *vp, int len)
 	q->blast = b;
 	/* b->next = 0; done by iallocb() */
 	q->len += BALLOC(b);
+	q->dlen += BLEN(b);
 	QDEBUG checkb(b, "qproduce");
 
 	if(q->state & Qstarve){
@@ -935,6 +948,7 @@ qbread(Queue *q, int len)
 	q->bfirst = b->next;
 	b->next = 0;
 	n = BLEN(b);
+	q->dlen -= n;
 	q->len -= BALLOC(b);
 	QDEBUG checkb(b, "qbread 1");
 
@@ -962,6 +976,7 @@ qbread(Queue *q, int len)
 				q->blast = b;
 			q->bfirst = b;
 			q->len += BALLOC(b);
+			q->dlen += n;
 		}
 		nb->wp = nb->rp + len;
 	}
@@ -1018,7 +1033,6 @@ qbwrite(Queue *q, Block *b)
 
 	dowakeup = 0;
 	n = BLEN(b);
-
 	qlock(&q->wlock);
 	if(waserror()){
 		qunlock(&q->wlock);
@@ -1058,6 +1072,7 @@ qbwrite(Queue *q, Block *b)
 	q->blast = b;
 	b->next = 0;
 	q->len += BALLOC(b);
+	q->dlen += n;
 	QDEBUG checkb(b, "qbwrite");
 
 	if(q->state & Qstarve){
@@ -1147,6 +1162,7 @@ qiwrite(Queue *q, void *vp, int len)
 			q->bfirst = b;
 		q->blast = b;
 		q->len += BALLOC(b);
+		q->dlen += n;
 
 		if(q->state & Qstarve){
 			q->state &= ~Qstarve;
@@ -1251,13 +1267,7 @@ qreopen(Queue *q)
 int
 qlen(Queue *q)
 {
-	int len;
-	Block *b;
-
-	len = 0;
-	for(b = q->bfirst; b; b= b->next)
-		len += BLEN(b);
-	return len;
+	return q->dlen;
 }
 
 /*
@@ -1314,6 +1324,7 @@ qflush(Queue *q)
 	bfirst = q->bfirst;
 	q->bfirst = 0;
 	q->len = 0;
+	q->dlen = 0;
 	iunlock(q);
 
 	/* free queued blocks */
diff --git a/port/sysfile.c b/port/sysfile.c
index 39d09918b0dd1bc616d2b1cf2dd8dc7000e230bb..13cc5dd47cd8f7fd1f17b92d7fb163f8e4be0c74 100644
--- a/port/sysfile.c
+++ b/port/sysfile.c
@@ -378,14 +378,15 @@ sysread(ulong *arg)
 	long n;
 	Chan *c;
 
-	validaddr(arg[1], arg[2], 1);
+	n = arg[2];
+	validaddr(arg[1], n, 1);
 	c = fdtochan(arg[0], OREAD, 1, 1);
+
 	if(waserror()) {
 		cclose(c);
 		nexterror();
 	}
 
-	n = arg[2];
 	dir = c->qid.path&CHDIR;
 
 	if(dir) {
@@ -443,24 +444,36 @@ long
 syswrite(ulong *arg)
 {
 	Chan *c;
-	long n;
+	long m, n;
+	uvlong oo;
 
 	validaddr(arg[1], arg[2], 0);
+	n = arg[2];
 	c = fdtochan(arg[0], OWRITE, 1, 1);
 	if(waserror()) {
 		cclose(c);
+		lock(c);
+		c->offset -= n;
+		unlock(c);
 		nexterror();
 	}
 
 	if(c->qid.path & CHDIR)
 		error(Eisdir);
 
-	n = devtab[c->type]->write(c, (void*)arg[1], arg[2], c->offset);
-
 	lock(c);
+	oo = c->offset;
 	c->offset += n;
 	unlock(c);
 
+	m = devtab[c->type]->write(c, (void*)arg[1], n, oo);
+
+	if(m < n){
+		lock(c);
+		c->offset = oo + m;
+		unlock(c);
+	}
+
 	poperror();
 	cclose(c);