mds: don't cow a null dentry

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index b4cf76d7fb6552a2fb3e0cf61ed38d73826a2be0..c33b5731c7ccc5b7c3fc6faaf344b92cc8b973e1 100644 (file)
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -1135,7 +1135,8 @@ void MDCache::journal_cow_inode(Mutation *mut, EMetaBlob *metablob, CInode *in,
 inode_t *MDCache::journal_dirty_inode(Mutation *mut, EMetaBlob *metablob, CInode *in, snapid_t follows)
 {
   CDentry *dn = in->get_projected_parent_dn();
-  journal_cow_dentry(mut, metablob, dn, follows);
+  if (!dn->is_null())  // no need to cow a null dentry
+    journal_cow_dentry(mut, metablob, dn, follows);
   return metablob->add_primary_dentry(dn, true, in, in->get_projected_inode());
 }