From e8337269eec5eefe7888a0cecc530febfb47bad2 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Tue, 6 Feb 1996 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1996-02-06

---
 port/devtinyfs.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/port/devtinyfs.c b/port/devtinyfs.c
index 9f12616f9cd80d1e8fe45275597bd866a04e068c..035364e5977c2bc0de79845844be6e23cd91323e 100644
--- a/port/devtinyfs.c
+++ b/port/devtinyfs.c
@@ -55,6 +55,7 @@ struct Mdata {
 
 typedef struct Tfile Tfile;
 struct Tfile {
+	Lock;
 	int	r;
 	char	name[NAMELEN];
 	ushort	bno;
@@ -182,6 +183,17 @@ validdata(Tfs *fs, uchar *p)
 	return md;
 }
 
+static Mdata*
+readdata(Tfs *fs, ulong bno, uchar *buf)
+{
+	if(bno >= fs->nblocks)
+		return 0;
+	n = devtab[fs->c->type].read(fs->c, buf, Blen, Blen*bno);
+	if(n != Blen)
+		return 0;
+	return validdata(fs, buf);
+}
+
 static int
 writedir(Tfs *fs, Tfile *f)
 {
@@ -603,6 +615,9 @@ tinyfsread(Chan *c, void *a, long n, ulong offset)
 	Tfs *fs;
 	Tfile *f;
 	int sofar, i;
+	ulong bno, tbno;
+	Mdata *md;
+	uchar buf[Blen];
 
 	if(c->qid.path & CHDIR)
 		return devdirread(c, a, n, tinyfstab, Ntinyfstab, tinyfsgen);
@@ -614,6 +629,22 @@ tinyfsread(Chan *c, void *a, long n, ulong offset)
 	if(n + offset >= f->length)
 		n = f->length - offset;
 
+	/* walk to first data block */
+	bno = f->dbno;
+	for(sofar = 0; sofar < offset; sofar += Blen){
+		md = readdata(fs, bno, buf);
+		if(md == 0)
+			error(Eio);
+		bno = GETS(md->bno);
+	}
+
+	/* read first block */
+	i = offset%Blen;
+
+	/* read data */
+	for(sofar = 0; sofar+Blen < offset; sofar += Blen){
+	
+
 	return n;
 }