kernel: mnt cache rework

avoid double entries in the cache for copen() and properly handle
locking so we wont just give up if we cant lock the Mntcache entry,
but drop the cache lock, qlock the Mntcache entry, and then recheck
the cache.

general cleanup (cdev -> ccache, use eqchantdqid())

1 files changed, 36 insertions, 0 deletions

diff --git a/sys/lib/acid/kernel b/sys/lib/acid/kernel
index 68c484b5d..7d082ec12 100644
--- a/sys/lib/acid/kernel
+++ b/sys/lib/acid/kernel
@@ -74,6 +74,20 @@ defn chans() {
 	}
 }
 
+defn findchan(dev,type,path) {
+	local c;
+
+	c = (Chan)chanalloc.list;
+	while c != 0 do {
+		if c.ref != 0 then {
+			if c.dev == dev && c.type == type && c.qid.path == path then
+				return c;
+		}
+		c=(Chan)c.link;
+	}
+	return 0;
+}
+
 defn nchans() {
 	local c, n;
 	
@@ -159,6 +173,27 @@ defn badchans() {
 	}
 }
 
+NHASH=128;
+defn mntcache() {
+	local i, m, c;
+
+	i=0; loop 1,NHASH do {
+		m = cache.hash[i];
+		while m != 0 do {
+			complex Mntcache m;
+			print(m\X, " dev ", m.dev\D, " type ", m.type, " qid (", 
+				m.qid.path, " ", m.qid.vers\D, ")\n");
+			c = findchan(m.dev, m.type, m.qid.path);
+			if c != 0 then {
+				print("	");
+				chan(c);
+			}
+			m = m.hash;
+		}
+		i = i+1;
+	}
+}
+
 // manipulate processes
 defn proctab(x) {
 	return procalloc.arena+sizeofProc*x;
@@ -379,5 +414,6 @@ if (map()[2]) != {} then {	// map has more than two elements -> active proc
 	needacid("proc");
 	needacid("chan");
 	needacid("segment");
+	needacid("cache");
 }
 }