1.  do not assume that Maxblock is >= the kernel's iounit.
2.  set the name of the fsysproc.
3.  use erealloc not realloc.

Notes:
Fri Jan 25 13:39:55 EST 2013 geoff
    this can't be right; you're using t.msize before it's initialised.
    i think i know what you intended, though.


Reference: /n/sources/patch/applied/acme-iounit
Date: Fri Jan 25 05:46:43 CET 2013
Signed-off-by: quanstro@quanstro.net
Reviewed-by: geoff

--- /sys/src/cmd/acme/fsys.c	Fri Jan 25 05:43:10 2013
+++ /sys/src/cmd/acme/fsys.c	Fri Jan 25 05:43:09 2013
@@ -145,6 +145,8 @@
 	Fcall t;
 	uchar *buf;
 
+	threadsetname("fsysproc");
+
 	x = nil;
 	for(;;){
 		buf = emalloc(messagesize+UTFmax);	/* overflow for appending partial rune in xfidwrite */
@@ -323,8 +325,9 @@
 
 	if(x->msize < 256)
 		return respond(x, &t, "version: message size too small");
-	messagesize = x->msize;
-	t.msize = messagesize;
+	if(t.msize > Maxblock)
+		t.msize = Maxblock;
+	messagesize = t.msize + IOHDRSZ;
 	if(strncmp(x->version, "9P2000", 6) != 0)
 		return respond(x, &t, "unrecognized 9P version");
 	t.version = "9P2000";
@@ -625,7 +628,7 @@
 			for(j=0; j<row.ncol; j++){
 				c = row.col[j];
 				for(k=0; k<c->nw; k++){
-					ids = realloc(ids, (nids+1)*sizeof(int));
+					ids = erealloc(ids, (nids+1)*sizeof(int));
 					ids[nids++] = c->w[k]->id;
 				}
 			}