nfs4: Avoid deleting nodes when unlinking

* Stop deleting Inode objects in VnodeToInode::Unlink().
* Allow ~VnodeToInode() to do this in nfs4_remove_vnode(), instead.

At the time the unlink hook is called, other threads could still have
the file open.

With this change, the nfs4 driver can pass the open/unlink test in the
Connectathon NFS testsuite.

Change-Id: I6e4f67fbafad73dd2eeb285dbd2b9fa9670bf5b5
Reviewed-on: https://review.haiku-os.org/c/haiku/+/9282
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

src/add-ons/kernel/file_systems/nfs4/VnodeToInode.cpp

@@ -39,13 +39,8 @@ VnodeToInode::Unlink(InodeNames* parent, const char* name)
 {
 	WriteLocker _(fLock);
 	if (fInode != NULL && !IsRoot()) {
-		bool removed = fInode->GetFileSystem()->InoIdMap()->RemoveName(fID,
-			parent, name);
-		if (removed) {
-			delete fInode;
-			fInode = NULL;
-		}
-		return removed;
+		return fInode->GetFileSystem()->InoIdMap()->RemoveName(fID, parent,
+			name);
 	}
 
 	return false;

src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp

@@ -341,13 +341,10 @@ nfs4_remove_vnode(fs_volume* volume, fs_vnode* vnode, bool reenter)
 	if (node == fs->Root())
 		return B_OK;
 
-	if (node != NULL && node->IsStale()) {
-		// in the case of a stale node, VnodeToInode::Unlink was never called by the client,
-		// so the Inode hasn't been deleted yet
-		vti->Clear();
-	}
+	// Verify that all known names have been unlinked.
+	FileInfo fileInfo;
+	ASSERT(fs->InoIdMap()->GetFileInfo(&fileInfo, vti->ID()) == B_ENTRY_NOT_FOUND);
 
-	ASSERT(vti->GetPointer() == NULL);
 	delete vti;
 
 	return B_OK;