From 8326d934d357f96eed694d59e47200e09462d2bb Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sun, 16 Apr 1995 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1995-04-16

---
 port/devsd.c | 50 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/port/devsd.c b/port/devsd.c
index 07e5c6ac9b4baa9b620d21a9118ca76162c69f57..31b1a09f32ba6350e6994cc63d4968eb90e17c5d 100644
--- a/port/devsd.c
+++ b/port/devsd.c
@@ -184,11 +184,36 @@ sdinit(void)
 Chan*
 sdattach(char *spec)
 {
-	int i;
+	int i, nfound;
+	Disk *d;
 
-	for(i = 0; i < ndisk; i++)
-		sdrdpart(&disk[i]);
-	
+	/*
+	 * If the drive wasn't ready when we tried to do a
+	 * read-capacity earlier (in sdinit()), try again.
+	 * It might be possible to be smarter here, and look at the
+	 * response from a test-unit-ready which would show if the
+	 * target was in the process of becoming ready.
+	 */
+	nfound = 0;
+	for(i = 0; i < ndisk; i++){	
+		d = &disk[i];
+		if(waserror()){
+			poperror();
+			continue;
+		}
+		if(d->size == 0 || d->bsize == 0){
+			if(scsicap(d->t, d->lun, &d->size, &d->bsize) != STok){
+				d->size = d->bsize = 0;
+				continue;
+			}
+		}
+		sdrdpart(d);
+		nfound++;
+		poperror();
+	}
+
+	if(nfound == 0)
+		return 0;
 	return devattach('w', spec);
 }
 
@@ -284,20 +309,6 @@ sdrdpart(Disk *d)
 	char *b, *line[Npart+2], *field[3];
 	static char MAGIC[] = "plan9 partitions";
 
-	/*
-	 * If the drive wasn't ready when we tried to do a
-	 * read-capacity earlier (in sdinit()), try again.
-	 * It might be possible to be smarter here, and look at the
-	 * response from a test-unit-ready which would show if the
-	 * target was in the process of becoming ready.
-	 */
-	if(d->size == 0 || d->bsize == 0){
-		if(scsicap(d->t, d->lun, &d->size, &d->bsize) != STok){
-			d->size = d->bsize = 0;
-			error(Eio);
-		}
-	}
-
 	b = scsialloc(d->bsize);
 	if(b == 0)
 		error(Enomem);
@@ -363,6 +374,9 @@ sdio(Chan *c, int write, char *a, ulong len, ulong offset)
 	d = &disk[DRIVE(c->qid)];
 	p = &d->table[PART(c->qid)];
 
+	if(d->bsize == 0)
+		error(Eio);
+
 	if(write && (d->inquire[0] & 0x1F) == TypeCD)
 		error(Eperm);