diff --git a/plugin/fugitive.vim b/plugin/fugitive.vim
index 970d158..dafe109 100644
--- a/plugin/fugitive.vim
+++ b/plugin/fugitive.vim
@@ -108,7 +108,7 @@ function! s:ExtractGitDir(path) abort
   let ofn = ""
   let nfn = fn
   while fn != ofn
-    if isdirectory(fn . '/.git')
+    if filereadable(fn . '/.git/HEAD')
       return s:sub(simplify(fnamemodify(fn . '/.git',':p')),'\W$','')
     elseif fn =~ '\.git$' && filereadable(fn . '/HEAD')
       return s:sub(simplify(fnamemodify(fn,':p')),'\W$','')