nodefs: get rid of recursiveConsiderDropInode

Instead, drop the node from all parents in OnForget.

Fixes issue #106, stress-loopback (from
https://github.com/rfjakob/fsstress) now passes 40+ iterations.

Change-Id: I9a6bc08b88fc4f5a8bb63d449b29430e5b24ee7a

fuse/nodefs/fsconnector.go

@@ -127,9 +127,17 @@ func (c *FileSystemConnector) forgetUpdate(nodeID uint64, forgetCount int) {
 
 	if forgotten, handled := c.inodeMap.Forget(nodeID, forgetCount); forgotten {
 		node := (*Inode)(unsafe.Pointer(handled))
+
 		node.mount.treeLock.Lock()
-		c.recursiveConsiderDropInode(node)
+		if len(node.children) > 0 || !node.Node().Deletable() ||
+			node == c.rootNode || node.mountPoint != nil {
+
+			node.mount.treeLock.Unlock()
+			return
+		}
 		node.mount.treeLock.Unlock()
+
+		node.fsInode.OnForget()
 	}
 	// TODO - try to drop children even forget was not successful.
 	c.verify()
@@ -140,39 +148,6 @@ func (c *FileSystemConnector) InodeHandleCount() int {
 	return c.inodeMap.Count()
 }
 
-// Must hold treeLock.
-
-func (c *FileSystemConnector) recursiveConsiderDropInode(n *Inode) (drop bool) {
-	delChildren := []string{}
-	for k, v := range n.children {
-		// Only consider children from the same mount, or
-		// already unmounted mountpoints.
-		if v.mountPoint == nil && c.recursiveConsiderDropInode(v) {
-			delChildren = append(delChildren, k)
-		}
-	}
-	for _, k := range delChildren {
-		ch := n.rmChild(k)
-		if ch == nil {
-			log.Panicf("trying to del child %q, but not present", k)
-		}
-		ch.fsInode.OnForget()
-	}
-
-	if len(n.children) > 0 || !n.Node().Deletable() {
-		return false
-	}
-	if n == c.rootNode || n.mountPoint != nil {
-		return false
-	}
-
-	n.openFilesMutex.Lock()
-	ok := len(n.openFiles) == 0
-	n.openFilesMutex.Unlock()
-
-	return ok
-}
-
 // Finds a node within the currently known inodes, returns the last
 // known node and the remaining unknown path components.  If parent is
 // nil, start from FUSE mountpoint.

fuse/pathfs/pathfs.go

@@ -417,8 +417,21 @@ func (n *pathInode) OnForget() {
 		return
 	}
 	n.pathFs.pathLock.Lock()
-	delete(n.pathFs.clientInodeMap, n.clientInode)
+	parents := make(map[parentData]struct{}, len(n.parents))
+	for k, v := range n.parents {
+		parents[k] = v
+	}
 	n.pathFs.pathLock.Unlock()
+
+	// Remove ourself from all parents. This will also remove the entry from
+	// clientInodeMap when the last parent is removed.
+	for p := range parents {
+		if ch := p.parent.Inode().GetChild(p.name); ch != nil && ch.Node() != n {
+			// Another node has taken our place - leave it alone.
+			continue
+		}
+		p.parent.Inode().RmChild(p.name)
+	}
 }
 
 ////////////////////////////////////////////////////////////////
@@ -521,7 +534,10 @@ func (n *pathInode) Rename(oldName string, newParent nodefs.Node, newName string
 	code = n.fs.Rename(oldPath, newPath, context)
 	if code.Ok() {
 		ch := n.Inode().RmChild(oldName)
-		p.Inode().AddChild(newName, ch)
+		if ch != nil {
+			// oldName may have been forgotten in the meantime.
+			p.Inode().AddChild(newName, ch)
+		}
 	}
 	return code
 }
@@ -609,7 +625,7 @@ func (n *pathInode) findChild(fi *fuse.Attr, name string, fullPath string) (out
 			out = v[0].node
 
 			if fi.Nlink == 1 {
-				log.Println("Found linked inode, but Nlink == 1", fullPath)
+				log.Println("Found linked inode, but Nlink == 1, ino=%d", fullPath, fi.Ino)
 			}
 		}
 		n.pathFs.pathLock.RUnlock()
@@ -619,7 +635,7 @@ func (n *pathInode) findChild(fi *fuse.Attr, name string, fullPath string) (out
 		out = n.createChild(name, fi.IsDir())
 		out.clientInode = fi.Ino
 	} else {
-		// should add 'out' as a child to n ?
+		n.Inode().AddChild(name, out.Inode())
 	}
 	return out
 }

unionfs/unionfs_test.go

@@ -1506,10 +1506,7 @@ func TestUnionFSBarf(t *testing.T) {
 	if err := os.Rename(wd+"/rw/dir/file", wd+"/rw/file"); err != nil {
 		t.Fatalf("os.Rename: %v", err)
 	}
-
-	err := os.Rename(wd+"/mnt/file", wd+"/mnt/dir2/file")
-	if fuse.ToStatus(err) != fuse.ENOENT {
-		// TODO - this should just succeed?
+	if err := os.Rename(wd+"/mnt/file", wd+"/mnt/dir2/file"); err != nil {
 		t.Fatalf("os.Rename: %v", err)
 	}
 }