From 9a308ed4a4d634d533ae598823ee1bdb5ab19307 Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@redhat.com>
Date: Tue, 3 Mar 2020 11:52:29 +0800
Subject: [PATCH] mds: don't add null dentry to frozen stray dir

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
---
 src/mds/MDCache.cc | 20 +-------------------
 src/mds/MDCache.h  |  1 -
 src/mds/Server.cc  | 26 +++++++++++++++++++++-----
 3 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index 214649467d5..6a1e1525f22 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -794,25 +794,6 @@ CDir *MDCache::get_stray_dir(CInode *in)
   return straydir;
 }
 
-CDentry *MDCache::get_or_create_stray_dentry(CInode *in)
-{
-  CDir *straydir = get_stray_dir(in);
-  string straydname;
-  in->name_stray_dentry(straydname);
-  CDentry *straydn = straydir->lookup(straydname);
-  if (!straydn) {
-    straydn = straydir->add_null_dentry(straydname);
-    straydn->mark_new();
-  } else {
-    ceph_assert(straydn->get_projected_linkage()->is_null());
-  }
-
-  straydn->state_set(CDentry::STATE_STRAY);
-  return straydn;
-}
-
-
-
 MDSCacheObject *MDCache::get_object(const MDSCacheObjectInfo &info)
 {
   // inode?
@@ -10813,6 +10794,7 @@ void MDCache::decode_replica_inode(CInode *&in, bufferlist::const_iterator& p, C
  
 void MDCache::encode_replica_stray(CDentry *straydn, mds_rank_t who, bufferlist& bl)
 {
+  ceph_assert(straydn->get_num_auth_pins());
   ENCODE_START(1, 1, bl);
   uint64_t features = mds->mdsmap->get_up_features();
   encode_replica_inode(get_myin(), who, bl, features);
diff --git a/src/mds/MDCache.h b/src/mds/MDCache.h
index 2c841481e32..6dd04f1bfb5 100644
--- a/src/mds/MDCache.h
+++ b/src/mds/MDCache.h
@@ -760,7 +760,6 @@ class MDCache {
 
   void open_foreign_mdsdir(inodeno_t ino, MDSContext *c);
   CDir *get_stray_dir(CInode *in);
-  CDentry *get_or_create_stray_dentry(CInode *in);
 
   /**
    * Find the given dentry (and whether it exists or not), its ancestors,
diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index ae5996e086f..a32babaa283 100644
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -3190,23 +3190,39 @@ bool Server::check_fragment_space(MDRequestRef &mdr, CDir *in)
 
 CDentry* Server::prepare_stray_dentry(MDRequestRef& mdr, CInode *in)
 {
+  string straydname;
+  in->name_stray_dentry(straydname);
+
   CDentry *straydn = mdr->straydn;
   if (straydn) {
-    string straydname;
-    in->name_stray_dentry(straydname);
     ceph_assert(straydn->get_name() == straydname);
     return straydn;
   }
-
   CDir *straydir = mdcache->get_stray_dir(in);
 
   if (!mdr->client_request->is_replay() &&
       !check_fragment_space(mdr, straydir))
-    return NULL;
+    return nullptr;
 
-  straydn = mdcache->get_or_create_stray_dentry(in);
+  straydn = straydir->lookup(straydname);
+  if (!straydn) {
+    if (straydir->is_frozen_dir()) {
+      dout(10) << __func__ << ": " << *straydir << " is frozen, waiting" << dendl;
+      mds->locker->drop_locks(mdr.get());
+      mdr->drop_local_auth_pins();
+      straydir->add_waiter(CInode::WAIT_UNFREEZE, new C_MDS_RetryRequest(mdcache, mdr));
+      return nullptr;
+    }
+    straydn = straydir->add_null_dentry(straydname);
+    straydn->mark_new();
+  } else {
+    ceph_assert(straydn->get_projected_linkage()->is_null());
+  }
+
+  straydn->state_set(CDentry::STATE_STRAY);
   mdr->straydn = straydn;
   mdr->pin(straydn);
+
   return straydn;
 }
 
-- 
2.47.3