In namex, drop the refs dirlookup returns

51e3d118 · Silas Boyd-Wickizer · 91c171fc · 51e3d118
--- a/kernel/fs.cc
+++ b/kernel/fs.cc
@@ -746,13 +746,15 @@ static struct inode*
 namex(inode *cwd, const char *path, int nameiparent, char *name)
 {
  struct inode *ip, *next;
+  bool drop_ref;
  int r;
-  scoped_gc_epoch e;

+  scoped_gc_epoch e;
  if(*path == '/') 
    ip = igetnoref(ROOTDEV, ROOTINO);
  else
    ip = cwd;
+  drop_ref = false;

  while((r = skipelem(&path, name)) == 1){
    // XXX Doing this here requires some annoying reasoning about all
@@ -765,20 +767,23 @@ namex(inode *cwd, const char *path, int nameiparent, char *name)
    // the caller declare the variables?  Would it help for the caller
    // to pass in an abstract scope?
    mtreadavar("inode:%x.%x", ip->dev, ip->inum);
-    next = 0;
-    if(next == 0){
-      if(ip->type == 0)
-        panic("namex");
-      if(ip->type != T_DIR)
-        return 0;
-      if(nameiparent && *path == '\0'){
-        // Stop one level early.
+    if(ip->type == 0)
+      panic("namex");
+    if(ip->type != T_DIR)
+      return 0;
+    if(nameiparent && *path == '\0'){
+      // Stop one level early.
+      if (!drop_ref)
        idup(ip);
-        return ip;
-      }
-      if((next = dirlookup(ip, name)) == 0)
-        return 0;
+      return ip;
    }
+
+    if((next = dirlookup(ip, name)) == 0)
+      return 0;
+    if (drop_ref)
+      iput(ip);
+
+    drop_ref = true;
    ip = next;
  }

@@ -792,7 +797,8 @@ namex(inode *cwd, const char *path, int nameiparent, char *name)
  // mtreadavar("inode:%x.%x", ip->dev, ip->inum);
  mtwriteavar("inode:%x.%x", ip->dev, ip->inum);

-  idup(ip);
+  if (!drop_ref)
+    idup(ip);
  return ip;
 }