From bb5ebd395f0831fd6d02d514ea1ec14f6bddbc9f Mon Sep 17 00:00:00 2001
From: "Yan, Zheng" <zyan@redhat.com>
Date: Fri, 7 Aug 2020 23:58:19 +0800
Subject: [PATCH] mds: distribute dirfrags for ephemeral distributed directory

Instead of distribute individual dir inodes inside the ephemeral
distributed dir. Distributing dirfrags can limit number of subtrees
created by the ephemeral dist pin.

This patch also unifies codes that handle export pin and ephemeral pin.

Fixes: https://tracker.ceph.com/issues/46696
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
---
 src/common/options.cc |   6 +
 src/mds/CDir.cc       |  36 ++++-
 src/mds/CDir.h        |   8 +-
 src/mds/CInode.cc     | 324 +++++++++++++++++-------------------------
 src/mds/CInode.h      |  21 +--
 src/mds/MDBalancer.cc | 110 +++++++++-----
 src/mds/MDCache.cc    |  79 +++++-----
 src/mds/MDCache.h     |   9 +-
 src/mds/MDSRank.cc    |  12 +-
 src/mds/Migrator.cc   |   3 +-
 src/mds/Server.cc     |   3 +-
 src/mds/journal.cc    |   4 +-
 src/mds/mdstypes.h    |   4 +-
 13 files changed, 304 insertions(+), 315 deletions(-)

diff --git a/src/common/options.cc b/src/common/options.cc
index 5ff3093996853..ee79029e9730d 100644
--- a/src/common/options.cc
+++ b/src/common/options.cc
@@ -8113,6 +8113,12 @@ std::vector<Option> get_mds_options() {
     .set_description("allow ephemeral distributed pinning of the loaded subtrees")
     .set_long_description("pin the immediate child directories of the loaded directory inode based on the consistent hash of the child's inode number. "),
 
+    Option("mds_export_ephemeral_distributed_factor", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
+    .set_default(2.0)
+    .set_min_max(1.0, 100.0)
+    .set_flag(Option::FLAG_RUNTIME)
+    .set_description("multiple of max_mds for splitting and distributing directory"),
+
     Option("mds_bal_sample_interval", Option::TYPE_FLOAT, Option::LEVEL_ADVANCED)
     .set_default(3.0)
     .set_description("interval in seconds between balancer ticks"),
diff --git a/src/mds/CDir.cc b/src/mds/CDir.cc
index d53d59dc6e6d5..3eedef3d1c1ed 100644
--- a/src/mds/CDir.cc
+++ b/src/mds/CDir.cc
@@ -1888,7 +1888,7 @@ CDentry *CDir::_load_dentry(
         if (in->get_inode()->is_dirty_rstat())
           in->mark_dirty_rstat();
 
-        in->maybe_ephemeral_rand(true, rand_threshold);
+        in->maybe_ephemeral_rand(rand_threshold);
         //in->hack_accessed = false;
         //in->hack_load_stamp = ceph_clock_now();
         //num_new_inodes_loaded++;
@@ -2635,6 +2635,26 @@ void CDir::_committed(int r, version_t v)
 
 // IMPORT/EXPORT
 
+mds_rank_t CDir::get_export_pin(bool inherit) const
+{
+  mds_rank_t export_pin = inode->get_export_pin(inherit);
+  if (export_pin == MDS_RANK_EPHEMERAL_DIST)
+    export_pin = mdcache->hash_into_rank_bucket(ino(), get_frag());
+  else if (export_pin == MDS_RANK_EPHEMERAL_RAND)
+    export_pin = mdcache->hash_into_rank_bucket(ino());
+  return export_pin;
+}
+
+bool CDir::is_exportable(mds_rank_t dest) const
+{
+  mds_rank_t export_pin = get_export_pin();
+  if (export_pin == dest)
+    return true;
+  if (export_pin >= 0)
+    return false;
+  return true;
+}
+
 void CDir::encode_export(bufferlist& bl)
 {
   ENCODE_START(1, 1, bl);
@@ -3701,5 +3721,19 @@ bool CDir::should_split_fast() const
   return effective_size > fast_limit;
 }
 
+bool CDir::should_merge() const
+{
+  if (get_frag() == frag_t())
+    return false;
+
+  if (inode->is_ephemeral_dist()) {
+    unsigned min_frag_bits = mdcache->get_ephemeral_dist_frag_bits();
+    if (min_frag_bits > 0 && get_frag().bits() < min_frag_bits + 1)
+      return false;
+  }
+
+  return (int)get_frag_size() < g_conf()->mds_bal_merge_size;
+}
+
 MEMPOOL_DEFINE_OBJECT_FACTORY(CDir, co_dir, mds_co);
 MEMPOOL_DEFINE_OBJECT_FACTORY(CDir::scrub_info_t, scrub_info_t, mds_co)
diff --git a/src/mds/CDir.h b/src/mds/CDir.h
index 952e108da0597..ad56749bb2695 100644
--- a/src/mds/CDir.h
+++ b/src/mds/CDir.h
@@ -439,10 +439,7 @@ public:
            (int)get_frag_size() > g_conf()->mds_bal_split_size;
   }
   bool should_split_fast() const;
-  bool should_merge() const {
-    return get_frag() != frag_t() &&
-	   (int)get_frag_size() < g_conf()->mds_bal_merge_size;
-  }
+  bool should_merge() const;
 
   mds_authority_t authority() const override;
   mds_authority_t get_dir_auth() const { return dir_auth; }
@@ -546,6 +543,9 @@ public:
   void finish_waiting(uint64_t mask, int result = 0);    // ditto
 
   // -- import/export --
+  mds_rank_t get_export_pin(bool inherit=true) const;
+  bool is_exportable(mds_rank_t dest) const;
+
   void encode_export(ceph::buffer::list& bl);
   void finish_export();
   void abort_export() {
diff --git a/src/mds/CInode.cc b/src/mds/CInode.cc
index 2d410e6d17a3b..b2c25d5783127 100644
--- a/src/mds/CInode.cc
+++ b/src/mds/CInode.cc
@@ -184,10 +184,12 @@ ostream& operator<<(ostream& out, const CInode& in)
     out << " snaprealm=" << in.snaprealm;
 
   if (in.state_test(CInode::STATE_AMBIGUOUSAUTH)) out << " AMBIGAUTH";
-  if (in.state_test(CInode::STATE_NEEDSRECOVER)) out << " needsrecover";
-  if (in.state_test(CInode::STATE_RECOVERING)) out << " recovering";
-  if (in.state_test(CInode::STATE_DIRTYPARENT)) out << " dirtyparent";
-  if (in.state_test(CInode::STATE_MISSINGOBJS)) out << " missingobjs";
+  if (in.state_test(CInode::STATE_NEEDSRECOVER)) out << " NEEDSRECOVER";
+  if (in.state_test(CInode::STATE_RECOVERING)) out << " RECOVERING";
+  if (in.state_test(CInode::STATE_DIRTYPARENT)) out << " DIRTYPARENT";
+  if (in.state_test(CInode::STATE_MISSINGOBJS)) out << " MISSINGOBJS";
+  if (in.is_ephemeral_dist()) out << " DISTEPHEMERALPIN";
+  if (in.is_ephemeral_rand()) out << " RANDEPHEMERALPIN";
   if (in.is_freezing_inode()) out << " FREEZING=" << in.auth_pin_freeze_allowance;
   if (in.is_frozen_inode()) out << " FROZEN";
   if (in.is_frozen_auth_pin()) out << " FROZEN_AUTHPIN";
@@ -487,10 +489,10 @@ void CInode::pop_and_dirty_projected_inode(LogSegment *ls, const MutationRef& mu
   if (mut)
     mut->remove_projected_node(this);
 
-  bool pool_update = get_inode()->layout.pool_id != front.inode->layout.pool_id;
-  bool pin_update = get_inode()->export_pin != front.inode->export_pin;
-  bool dist_update = get_inode()->export_ephemeral_distributed_pin !=
-		     front.inode->export_ephemeral_distributed_pin;
+  bool pool_updated = get_inode()->layout.pool_id != front.inode->layout.pool_id;
+  bool pin_updated = (get_inode()->export_pin != front.inode->export_pin) ||
+		     (get_inode()->export_ephemeral_distributed_pin !=
+		      front.inode->export_ephemeral_distributed_pin);
 
   reset_inode(std::move(front.inode));
   if (front.xattrs != get_xattrs())
@@ -503,12 +505,10 @@ void CInode::pop_and_dirty_projected_inode(LogSegment *ls, const MutationRef& mu
 
   mark_dirty(ls);
   if (get_inode()->is_backtrace_updated())
-    mark_dirty_parent(ls, pool_update);
+    mark_dirty_parent(ls, pool_updated);
 
-  if (pin_update)
+  if (pin_updated)
     maybe_export_pin(true);
-  if (dist_update)
-    maybe_ephemeral_dist_children(true);
 }
 
 sr_t *CInode::prepare_new_srnode(snapid_t snapid)
@@ -815,7 +815,7 @@ CDir *CInode::add_dirfrag(CDir *dir)
     dir->get(CDir::PIN_STICKY);
   }
 
-  maybe_pin();
+  maybe_export_pin();
 
   return dir;
 }
@@ -2145,11 +2145,12 @@ void CInode::decode_lock_ipolicy(bufferlist::const_iterator& p)
     }
   }
   DECODE_FINISH(p);
-  mds_rank_t old_export_pin = get_inode()->export_pin;
-  bool old_ephemeral_pin = get_inode()->export_ephemeral_distributed_pin;
+
+  bool pin_updated = (get_inode()->export_pin != _inode->export_pin) ||
+		     (get_inode()->export_ephemeral_distributed_pin !=
+		      _inode->export_ephemeral_distributed_pin);
   reset_inode(std::move(_inode));
-  maybe_export_pin(old_export_pin != get_inode()->export_pin);
-  maybe_ephemeral_dist_children(old_ephemeral_pin != get_inode()->export_ephemeral_distributed_pin);
+  maybe_export_pin(pin_updated);
 }
 
 void CInode::encode_lock_state(int type, bufferlist& bl)
@@ -4404,13 +4405,8 @@ void CInode::decode_import(bufferlist::const_iterator& p,
     decode(s, p);
     s &= MASK_STATE_EXPORTED;
 
-    if (s & STATE_RANDEPHEMERALPIN) {
-      set_ephemeral_rand(true);
-    }
-    if (s & STATE_DISTEPHEMERALPIN) {
-      set_ephemeral_dist(true);
-    }
-
+    set_ephemeral_pin((s & STATE_DISTEPHEMERALPIN),
+		      (s & STATE_RANDEPHEMERALPIN));
     state_set(STATE_AUTH | s);
   }
 
@@ -5336,16 +5332,35 @@ int64_t CInode::get_backtrace_pool() const
   }
 }
 
-void CInode::queue_export_pin(mds_rank_t target)
+void CInode::queue_export_pin(mds_rank_t export_pin)
 {
   if (state_test(CInode::STATE_QUEUEDEXPORTPIN))
     return;
 
+  mds_rank_t target;
+  if (export_pin >= 0)
+    target = export_pin;
+  else if (export_pin == MDS_RANK_EPHEMERAL_RAND)
+    target = mdcache->hash_into_rank_bucket(ino());
+  else
+    target = MDS_RANK_NONE;
+
+  unsigned min_frag_bits = mdcache->get_ephemeral_dist_frag_bits();
   bool queue = false;
   for (auto& p : dirfrags) {
     CDir *dir = p.second;
     if (!dir->is_auth())
       continue;
+
+    if (export_pin == MDS_RANK_EPHEMERAL_DIST) {
+      if (dir->get_frag().bits() < min_frag_bits) {
+	// needs split
+	queue = true;
+	break;
+      }
+      target = mdcache->hash_into_rank_bucket(ino(), dir->get_frag());
+    }
+
     if (target != MDS_RANK_NONE) {
       if (dir->is_subtree_root()) {
 	// set auxsubtree bit or export it
@@ -5360,11 +5375,13 @@ void CInode::queue_export_pin(mds_rank_t target)
       // clear aux subtrees ?
       queue = dir->state_test(CDir::STATE_AUXSUBTREE);
     }
-    if (queue) {
-      state_set(CInode::STATE_QUEUEDEXPORTPIN);
-      mdcache->export_pin_queue.insert(this);
+
+    if (queue)
       break;
-    }
+  }
+  if (queue) {
+    state_set(CInode::STATE_QUEUEDEXPORTPIN);
+    mdcache->export_pin_queue.insert(this);
   }
 }
 
@@ -5377,145 +5394,71 @@ void CInode::maybe_export_pin(bool update)
 
   dout(15) << __func__ << " update=" << update << " " << *this << dendl;
 
-  mds_rank_t export_pin = get_export_pin(false, false);
-  if (export_pin == MDS_RANK_NONE && !update) {
+  mds_rank_t export_pin = get_export_pin(false);
+  if (export_pin == MDS_RANK_NONE && !update)
     return;
-  }
 
-  /* disable ephemeral pins */
-  set_ephemeral_dist(false);
-  set_ephemeral_rand(false);
+  check_pin_policy(export_pin);
   queue_export_pin(export_pin);
 }
 
-void CInode::set_ephemeral_dist(bool yes)
-{
-  if (yes) {
-    if (!state_test(CInode::STATE_DISTEPHEMERALPIN)) {
-      state_set(CInode::STATE_DISTEPHEMERALPIN);
-      auto p = mdcache->dist_ephemeral_pins.insert(this);
-      ceph_assert(p.second);
-    }
-  } else {
-    /* avoid std::set::erase if unnecessary */
-    if (state_test(CInode::STATE_DISTEPHEMERALPIN)) {
-      dout(10) << "clearing ephemeral distributed pin on " << *this << dendl;
-      state_clear(CInode::STATE_DISTEPHEMERALPIN);
-      auto count = mdcache->dist_ephemeral_pins.erase(this);
-      ceph_assert(count == 1);
-      queue_export_pin(MDS_RANK_NONE);
-    }
-  }
-}
-
-void CInode::maybe_ephemeral_dist(bool update)
+void CInode::set_ephemeral_pin(bool dist, bool rand)
 {
-  if (!mdcache->get_export_ephemeral_distributed_config()) {
-    dout(15) << __func__ << " config false: cannot ephemeral distributed pin " << *this << dendl;
-    set_ephemeral_dist(false);
-    return;
-  } else if (!is_dir() || !is_normal()) {
-    dout(15) << __func__ << " !dir or !normal: cannot ephemeral distributed pin " << *this << dendl;
-    set_ephemeral_dist(false);
-    return;
-  } else if (get_inode()->nlink == 0) {
-    dout(15) << __func__ << " unlinked directory: cannot ephemeral distributed pin " << *this << dendl;
-    set_ephemeral_dist(false);
-    return;
-  } else if (!update && state_test(CInode::STATE_DISTEPHEMERALPIN)) {
-    dout(15) << __func__ << " requeueing already pinned " << *this << dendl;
-    queue_export_pin(mdcache->hash_into_rank_bucket(ino()));
-    return;
-  }
-
-  dout(15) << __func__ << " update=" << update << " " << *this << dendl;
-
-  auto dir = get_parent_dir();
-  if (!dir) {
-    return;
-  }
-
-  bool pin = dir->get_inode()->get_inode()->export_ephemeral_distributed_pin;
-  if (pin) {
-    dout(10) << __func__ << "  ephemeral distributed pinning " << *this << dendl;
-    set_ephemeral_dist(true);
-    queue_export_pin(mdcache->hash_into_rank_bucket(ino()));
-  } else if (update) {
-    set_ephemeral_dist(false);
-    queue_export_pin(MDS_RANK_NONE);
-  }
-}
-
-void CInode::maybe_ephemeral_dist_children(bool update)
-{
-  if (!mdcache->get_export_ephemeral_distributed_config()) {
-    dout(15) << __func__ << " config false: cannot ephemeral distributed pin " << *this << dendl;
-    return;
-  } else if (!is_dir() || !is_normal()) {
-    dout(15) << __func__ << " !dir or !normal: cannot ephemeral distributed pin " << *this << dendl;
-    return;
-  } else if (get_inode()->nlink == 0) {
-    dout(15) << __func__ << " unlinked directory: cannot ephemeral distributed pin " << *this << dendl;
-    return;
-  }
-
-  bool pin = get_inode()->export_ephemeral_distributed_pin;
-  /* FIXME: expensive to iterate children when not updating */
-  if (!pin && !update) {
+  unsigned state = 0;
+  if (dist)
+    state |= STATE_DISTEPHEMERALPIN;
+  if (rand)
+    state |= STATE_RANDEPHEMERALPIN;
+  if (!state)
     return;
-  }
 
-  dout(10) << __func__ << " maybe ephemerally pinning children of " << *this << dendl;
-  for (auto& p : dirfrags) {
-    auto& dir = p.second;
-    for (auto& q : *dir) {
-      auto& dn = q.second;
-      auto&& in = dn->get_linkage()->get_inode();
-      if (in && in->is_dir()) {
-        in->maybe_ephemeral_dist(update);
-      }
+  if (state_test(state) != state) {
+    dout(10) << "set ephemeral (" << (dist ? "dist" : "")
+	     << (rand ? " rand" : "") << ") pin on " << *this << dendl;
+    if (!is_ephemerally_pinned()) {
+      auto p = mdcache->export_ephemeral_pins.insert(this);
+      ceph_assert(p.second);
     }
+    state_set(state);
   }
 }
 
-void CInode::set_ephemeral_rand(bool yes)
+void CInode::clear_ephemeral_pin(bool dist, bool rand)
 {
-  if (yes) {
-    if (!state_test(CInode::STATE_RANDEPHEMERALPIN)) {
-      state_set(CInode::STATE_RANDEPHEMERALPIN);
-      auto p = mdcache->rand_ephemeral_pins.insert(this);
-      ceph_assert(p.second);
-    }
-  } else {
-    if (state_test(CInode::STATE_RANDEPHEMERALPIN)) {
-      dout(10) << "clearing ephemeral random pin on " << *this << dendl;
-      state_clear(CInode::STATE_RANDEPHEMERALPIN);
-      auto count = mdcache->rand_ephemeral_pins.erase(this);
+  unsigned state = 0;
+  if (dist)
+    state |= STATE_DISTEPHEMERALPIN;
+  if (rand)
+    state |= STATE_RANDEPHEMERALPIN;
+
+  if (state_test(state)) {
+    dout(10) << "clear ephemeral (" << (dist ? "dist" : "")
+	     << (rand ? " rand" : "") << ") pin on " << *this << dendl;
+    state_clear(state);
+    if (!is_ephemerally_pinned()) {
+      auto count = mdcache->export_ephemeral_pins.erase(this);
       ceph_assert(count == 1);
-      queue_export_pin(MDS_RANK_NONE);
     }
   }
 }
 
-void CInode::maybe_ephemeral_rand(bool fresh, double threshold)
+void CInode::maybe_ephemeral_rand(double threshold)
 {
   if (!mdcache->get_export_ephemeral_random_config()) {
     dout(15) << __func__ << " config false: cannot ephemeral random pin " << *this << dendl;
-    set_ephemeral_rand(false);
+    clear_ephemeral_pin(false, true);
     return;
   } else if (!is_dir() || !is_normal()) {
     dout(15) << __func__ << " !dir or !normal: cannot ephemeral random pin " << *this << dendl;
-    set_ephemeral_rand(false);
+    clear_ephemeral_pin(false, true);
     return;
   } else if (get_inode()->nlink == 0) {
     dout(15) << __func__ << " unlinked directory: cannot ephemeral random pin " << *this << dendl;
-    set_ephemeral_rand(false);
+    clear_ephemeral_pin(false, true);
     return;
   } else if (state_test(CInode::STATE_RANDEPHEMERALPIN)) {
     dout(10) << __func__ << " already ephemeral random pinned: requeueing " << *this << dendl;
-    queue_export_pin(mdcache->hash_into_rank_bucket(ino()));
-    return;
-  } else if (!fresh) {
+    queue_export_pin(MDS_RANK_EPHEMERAL_RAND);
     return;
   }
 
@@ -5533,8 +5476,8 @@ void CInode::maybe_ephemeral_rand(bool fresh, double threshold)
 
   if (n <= threshold) {
     dout(10) << __func__ << " randomly export pinning " << *this << dendl;
-    set_ephemeral_rand(true);
-    queue_export_pin(mdcache->hash_into_rank_bucket(ino()));
+    set_ephemeral_pin(false, true);
+    queue_export_pin(MDS_RANK_EPHEMERAL_RAND);
   }
 }
 
@@ -5557,43 +5500,19 @@ void CInode::set_export_pin(mds_rank_t rank)
   maybe_export_pin(true);
 }
 
-void CInode::check_pin_policy()
+mds_rank_t CInode::get_export_pin(bool inherit) const
 {
-  const CInode *in = this;
-  mds_rank_t etarget = MDS_RANK_NONE;
-  while (true) {
-    if (in->is_system())
-      break;
-    const CDentry *pdn = in->get_parent_dn();
-    if (!pdn)
-      break;
-    if (in->get_inode()->nlink == 0) {
-      // ignore export pin for unlinked directory
-      return;
-    } else if (etarget != MDS_RANK_NONE && in->has_ephemeral_policy()) {
-      return;
-    } else if (in->get_inode()->export_pin >= 0) {
-      /* clear any epin policy */
-      set_ephemeral_dist(false);
-      set_ephemeral_rand(false);
-      return;
-    } else if (etarget == MDS_RANK_NONE && in->is_ephemerally_pinned()) {
-      /* If a parent overrides a grandparent ephemeral pin policy with an export pin, we use that export pin instead. */
-      etarget = mdcache->hash_into_rank_bucket(in->ino());
-    }
-    in = pdn->get_dir()->inode;
-  }
-}
+  if (!g_conf()->mds_bal_export_pin)
+    return MDS_RANK_NONE;
 
-mds_rank_t CInode::get_export_pin(bool inherit, bool ephemeral) const
-{
   /* An inode that is export pinned may not necessarily be a subtree root, we
    * need to traverse the parents. A base or system inode cannot be pinned.
    * N.B. inodes not yet linked into a dir (i.e. anonymous inodes) will not
    * have a parent yet.
    */
+  mds_rank_t r_target = MDS_RANK_NONE;
   const CInode *in = this;
-  mds_rank_t etarget = MDS_RANK_NONE;
+  const CDir *dir = nullptr;
   while (true) {
     if (in->is_system())
       break;
@@ -5602,26 +5521,54 @@ mds_rank_t CInode::get_export_pin(bool inherit, bool ephemeral) const
       break;
     if (in->get_inode()->nlink == 0) {
       // ignore export pin for unlinked directory
-      return MDS_RANK_NONE;
-    } else if (etarget != MDS_RANK_NONE && in->has_ephemeral_policy()) {
-      return etarget;
-    } else if (in->get_inode()->export_pin >= 0) {
+      break;
+    }
+
+    if (in->get_inode()->export_pin >= 0) {
       return in->get_inode()->export_pin;
-    } else if (etarget == MDS_RANK_NONE && ephemeral && in->is_ephemerally_pinned()) {
+    } else if (in->get_inode()->export_ephemeral_distributed_pin &&
+	       mdcache->get_export_ephemeral_distributed_config()) {
+      if (in != this)
+	return mdcache->hash_into_rank_bucket(in->ino(), dir->get_frag());
+      return MDS_RANK_EPHEMERAL_DIST;
+    } else if (r_target != MDS_RANK_NONE && in->get_inode()->export_ephemeral_random_pin > 0.0) {
+      return r_target;
+    } else if (r_target == MDS_RANK_NONE && in->is_ephemeral_rand() &&
+	       mdcache->get_export_ephemeral_random_config()) {
       /* If a parent overrides a grandparent ephemeral pin policy with an export pin, we use that export pin instead. */
-      etarget = mdcache->hash_into_rank_bucket(in->ino());
-      if (!inherit) return etarget;
+      if (!inherit)
+	return MDS_RANK_EPHEMERAL_RAND;
+      if (in == this)
+	r_target = MDS_RANK_EPHEMERAL_RAND;
+      else
+	r_target = mdcache->hash_into_rank_bucket(in->ino());
     }
 
-    if (!inherit) {
+    if (!inherit)
       break;
-    }
-    in = pdn->get_dir()->inode;
+    dir = pdn->get_dir();
+    in = dir->inode;
   }
   return MDS_RANK_NONE;
 }
 
-double CInode::get_ephemeral_rand(bool inherit) const
+void CInode::check_pin_policy(mds_rank_t export_pin)
+{
+  if (export_pin == MDS_RANK_EPHEMERAL_DIST) {
+    set_ephemeral_pin(true, false);
+    clear_ephemeral_pin(false, true);
+  } else if (export_pin == MDS_RANK_EPHEMERAL_RAND) {
+    set_ephemeral_pin(false, true);
+    clear_ephemeral_pin(true, false);
+  } else if (is_ephemerally_pinned()) {
+    // export_pin >= 0 || export_pin == MDS_RANK_NONE
+    clear_ephemeral_pin(true, true);
+    if (export_pin != get_inode()->export_pin) // inherited export_pin
+      queue_export_pin(MDS_RANK_NONE);
+  }
+}
+
+double CInode::get_ephemeral_rand() const
 {
   /* N.B. inodes not yet linked into a dir (i.e. anonymous inodes) will not
    * have a parent yet.
@@ -5644,28 +5591,15 @@ double CInode::get_ephemeral_rand(bool inherit) const
     /* An export_pin overrides only if no closer parent (incl. this one) has a
      * random pin set.
      */
-    if (in->get_inode()->export_pin >= 0)
+    if (in->get_inode()->export_pin >= 0 ||
+	in->get_inode()->export_ephemeral_distributed_pin)
       return 0.0;
 
-    if (!inherit)
-      break;
     in = pdn->get_dir()->inode;
   }
   return 0.0;
 }
 
-bool CInode::is_exportable(mds_rank_t dest) const
-{
-  mds_rank_t pin = get_export_pin();
-  if (pin == dest) {
-    return true;
-  } else if (pin >= 0) {
-    return false;
-  } else {
-    return true;
-  }
-}
-
 void CInode::get_nested_dirfrags(std::vector<CDir*>& v) const
 {
   for (const auto &p : dirfrags) {
diff --git a/src/mds/CInode.h b/src/mds/CInode.h
index 33698fe01a2a6..f792e9f133e31 100644
--- a/src/mds/CInode.h
+++ b/src/mds/CInode.h
@@ -1052,24 +1052,22 @@ class CInode : public MDSCacheObject, public InodeStoreBase, public Counter<CIno
     return !projected_parent.empty();
   }
 
-  mds_rank_t get_export_pin(bool inherit=true, bool ephemeral=true) const;
+  mds_rank_t get_export_pin(bool inherit=true) const;
+  void check_pin_policy(mds_rank_t target);
   void set_export_pin(mds_rank_t rank);
   void queue_export_pin(mds_rank_t target);
   void maybe_export_pin(bool update=false);
 
-  void check_pin_policy();
+  void set_ephemeral_pin(bool dist, bool rand);
+  void clear_ephemeral_pin(bool dist, bool rand);
 
-  void set_ephemeral_dist(bool yes);
-  void maybe_ephemeral_dist(bool update=false);
-  void maybe_ephemeral_dist_children(bool update=false);
   void setxattr_ephemeral_dist(bool val=false);
   bool is_ephemeral_dist() const {
     return state_test(STATE_DISTEPHEMERALPIN);
   }
 
-  double get_ephemeral_rand(bool inherit=true) const;
-  void set_ephemeral_rand(bool yes);
-  void maybe_ephemeral_rand(bool fresh=false, double threshold=-1.0);
+  double get_ephemeral_rand() const;
+  void maybe_ephemeral_rand(double threshold=-1.0);
   void setxattr_ephemeral_rand(double prob=0.0);
   bool is_ephemeral_rand() const {
     return state_test(STATE_RANDEPHEMERALPIN);
@@ -1083,13 +1081,6 @@ class CInode : public MDSCacheObject, public InodeStoreBase, public Counter<CIno
     return state_test(STATE_DISTEPHEMERALPIN) ||
            state_test(STATE_RANDEPHEMERALPIN);
   }
-  bool is_exportable(mds_rank_t dest) const;
-
-  void maybe_pin() {
-    maybe_export_pin();
-    maybe_ephemeral_dist();
-    maybe_ephemeral_rand();
-  }
 
   void print(std::ostream& out) override;
   void dump(ceph::Formatter *f, int flags = DUMP_DEFAULT) const;
diff --git a/src/mds/MDBalancer.cc b/src/mds/MDBalancer.cc
index 2fd700228cb18..f57661f0a355f 100644
--- a/src/mds/MDBalancer.cc
+++ b/src/mds/MDBalancer.cc
@@ -92,7 +92,10 @@ void MDBalancer::handle_conf_change(const std::set<std::string>& changed, const
 
 void MDBalancer::handle_export_pins(void)
 {
-  auto &q = mds->mdcache->export_pin_queue;
+  const mds_rank_t max_mds = mds->mdsmap->get_max_mds();
+  auto mdcache = mds->mdcache;
+
+  auto &q = mdcache->export_pin_queue;
   auto it = q.begin();
   dout(20) << "export_pin_queue size=" << q.size() << dendl;
   while (it != q.end()) {
@@ -100,26 +103,47 @@ void MDBalancer::handle_export_pins(void)
     CInode *in = *cur;
     ceph_assert(in->is_dir());
 
-    in->check_pin_policy();
     mds_rank_t export_pin = in->get_export_pin(false);
-    if (export_pin >= mds->mdsmap->get_max_mds()) {
+    in->check_pin_policy(export_pin);
+
+    if (export_pin >= max_mds) {
       dout(20) << " delay export_pin=" << export_pin << " on " << *in << dendl;
       in->state_clear(CInode::STATE_QUEUEDEXPORTPIN);
       q.erase(cur);
 
       in->state_set(CInode::STATE_DELAYEDEXPORTPIN);
-      mds->mdcache->export_pin_delayed_queue.insert(in);
+      mdcache->export_pin_delayed_queue.insert(in);
       continue;
-    } else {
-      dout(20) << " executing export_pin=" << export_pin << " on " << *in << dendl;
     }
 
+    dout(20) << " executing export_pin=" << export_pin << " on " << *in << dendl;
+    unsigned min_frag_bits = 0;
+    mds_rank_t target = MDS_RANK_NONE;
+    if (export_pin >= 0)
+      target = export_pin;
+    else if (export_pin == MDS_RANK_EPHEMERAL_RAND)
+      target = mdcache->hash_into_rank_bucket(in->ino());
+    else if (export_pin == MDS_RANK_EPHEMERAL_DIST)
+      min_frag_bits = mdcache->get_ephemeral_dist_frag_bits();
+
     bool remove = true;
     for (auto&& dir : in->get_dirfrags()) {
       if (!dir->is_auth())
 	continue;
 
-      if (export_pin == MDS_RANK_NONE) {
+      if (export_pin == MDS_RANK_EPHEMERAL_DIST) {
+	if (dir->get_frag().bits() < min_frag_bits) {
+	  if (!dir->state_test(CDir::STATE_CREATING) &&
+	      !dir->is_frozen() && !dir->is_freezing()) {
+	    queue_split(dir, true);
+	  }
+	  remove = false;
+	  continue;
+	}
+	target = mdcache->hash_into_rank_bucket(in->ino(), dir->get_frag());
+      }
+
+      if (target == MDS_RANK_NONE) {
 	if (dir->state_test(CDir::STATE_AUXSUBTREE)) {
 	  if (dir->is_frozen() || dir->is_freezing()) {
 	    // try again later
@@ -130,7 +154,7 @@ void MDBalancer::handle_export_pins(void)
 	  dir->state_clear(CDir::STATE_AUXSUBTREE);
 	  mds->mdcache->try_subtree_merge(dir);
 	}
-      } else if (export_pin == mds->get_nodeid()) {
+      } else if (target == mds->get_nodeid()) {
         if (dir->state_test(CDir::STATE_AUXSUBTREE)) {
           ceph_assert(dir->is_subtree_root());
         } else if (dir->state_test(CDir::STATE_CREATING) ||
@@ -151,7 +175,7 @@ void MDBalancer::handle_export_pins(void)
          * be sent back by the importer.
          */
         if (dir->get_num_head_items() > 0) {
-	  mds->mdcache->migrator->export_dir(dir, export_pin);
+	  mds->mdcache->migrator->export_dir(dir, target);
         }
 	remove = false;
       }
@@ -163,7 +187,7 @@ void MDBalancer::handle_export_pins(void)
     }
   }
 
-  std::vector<CDir *> authsubs = mds->mdcache->get_auth_subtrees();
+  std::vector<CDir*> authsubs = mdcache->get_auth_subtrees();
   bool print_auth_subtrees = true;
 
   if (authsubs.size() > AUTH_TREES_THRESHOLD &&
@@ -175,18 +199,20 @@ void MDBalancer::handle_export_pins(void)
 
   for (auto &cd : authsubs) {
     mds_rank_t export_pin = cd->inode->get_export_pin();
+    cd->inode->check_pin_policy(export_pin);
 
-    if (print_auth_subtrees) {
-      dout(25) << "auth tree " << *cd << " export_pin=" << export_pin <<
-		  dendl;
+    if (export_pin == MDS_RANK_EPHEMERAL_DIST) {
+      export_pin = mdcache->hash_into_rank_bucket(cd->ino(), cd->get_frag());
+    } else if (export_pin == MDS_RANK_EPHEMERAL_RAND) {
+      export_pin = mdcache->hash_into_rank_bucket(cd->ino());
     }
 
-    if (export_pin >= 0 && export_pin < mds->mdsmap->get_max_mds()) {
-      if (export_pin == mds->get_nodeid()) {
-        cd->get_inode()->check_pin_policy();
-      } else {
-        mds->mdcache->migrator->export_dir(cd, export_pin);
-      }
+    if (print_auth_subtrees)
+      dout(25) << "auth tree " << *cd << " export_pin=" << export_pin << dendl;
+
+    if (export_pin >= 0 && export_pin != mds->get_nodeid() &&
+	export_pin < mds->mdsmap->get_max_mds()) {
+      mdcache->migrator->export_dir(cd, export_pin);
     }
   }
 }
@@ -521,10 +547,10 @@ void MDBalancer::queue_split(const CDir *dir, bool fast)
   dout(10) << __func__ << " enqueuing " << *dir
                        << " (fast=" << fast << ")" << dendl;
 
-  const dirfrag_t frag = dir->dirfrag();
+  const dirfrag_t df = dir->dirfrag();
 
-  auto callback = [this, frag](int r) {
-    if (split_pending.erase(frag) == 0) {
+  auto callback = [this, df](int r) {
+    if (split_pending.erase(df) == 0) {
       // Someone beat me to it.  This can happen in the fast splitting
       // path, because we spawn two contexts, one with mds->timer and
       // one with mds->queue_waiter.  The loser can safely just drop
@@ -532,27 +558,32 @@ void MDBalancer::queue_split(const CDir *dir, bool fast)
       return;
     }
 
-    CDir *split_dir = mds->mdcache->get_dirfrag(frag);
-    if (!split_dir) {
-      dout(10) << "drop split on " << frag << " because not in cache" << dendl;
+    auto mdcache = mds->mdcache;
+
+    CDir *dir = mdcache->get_dirfrag(df);
+    if (!dir) {
+      dout(10) << "drop split on " << df << " because not in cache" << dendl;
       return;
     }
-    if (!split_dir->is_auth()) {
-      dout(10) << "drop split on " << frag << " because non-auth" << dendl;
+    if (!dir->is_auth()) {
+      dout(10) << "drop split on " << df << " because non-auth" << dendl;
       return;
     }
 
     // Pass on to MDCache: note that the split might still not
     // happen if the checks in MDCache::can_fragment fail.
-    dout(10) << __func__ << " splitting " << *split_dir << dendl;
-    mds->mdcache->split_dir(split_dir, g_conf()->mds_bal_split_bits);
+    dout(10) << __func__ << " splitting " << *dir << dendl;
+    int bits = g_conf()->mds_bal_split_bits;
+    if (dir->inode->is_ephemeral_dist()) {
+      unsigned min_frag_bits = mdcache->get_ephemeral_dist_frag_bits();
+      if (df.frag.bits() + bits < min_frag_bits)
+	bits = min_frag_bits - df.frag.bits();
+    }
+    mdcache->split_dir(dir, bits);
   };
 
-  bool is_new = false;
-  if (split_pending.count(frag) == 0) {
-    split_pending.insert(frag);
-    is_new = true;
-  }
+  auto ret = split_pending.insert(df);
+  bool is_new = ret.second;
 
   if (fast) {
     // Do the split ASAP: enqueue it in the MDSRank waiters which are
@@ -579,7 +610,8 @@ void MDBalancer::queue_merge(CDir *dir)
     // starting one), and this context is the only one that erases it.
     merge_pending.erase(frag);
 
-    CDir *dir = mds->mdcache->get_dirfrag(frag);
+    auto mdcache = mds->mdcache;
+    CDir *dir = mdcache->get_dirfrag(frag);
     if (!dir) {
       dout(10) << "drop merge on " << frag << " because not in cache" << dendl;
       return;
@@ -595,8 +627,12 @@ void MDBalancer::queue_merge(CDir *dir)
 
     CInode *diri = dir->get_inode();
 
+    unsigned min_frag_bits = 0;
+    if (diri->is_ephemeral_dist())
+      min_frag_bits = mdcache->get_ephemeral_dist_frag_bits();
+
     frag_t fg = dir->get_frag();
-    while (fg != frag_t()) {
+    while (fg.bits() > min_frag_bits) {
       frag_t sibfg = fg.get_sibling();
       auto&& [complete, sibs] = diri->get_dirfrags_under(sibfg);
       if (!complete) {
@@ -619,7 +655,7 @@ void MDBalancer::queue_merge(CDir *dir)
     }
 
     if (fg != dir->get_frag())
-      mds->mdcache->merge_dir(diri, fg);
+      mdcache->merge_dir(diri, fg);
   };
 
   if (merge_pending.count(frag) == 0) {
diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index 76fb22c4ccafe..eb2802671c720 100644
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -221,27 +221,26 @@ void MDCache::handle_conf_change(const std::set<std::string>& changed, const MDS
     cache_memory_limit = g_conf().get_val<Option::size_t>("mds_cache_memory_limit");
   if (changed.count("mds_cache_reservation"))
     cache_reservation = g_conf().get_val<double>("mds_cache_reservation");
+
+  bool ephemeral_pin_config_changed = false;
   if (changed.count("mds_export_ephemeral_distributed")) {
     export_ephemeral_distributed_config = g_conf().get_val<bool>("mds_export_ephemeral_distributed");
     dout(10) << "Migrating any ephemeral distributed pinned inodes" << dendl;
     /* copy to vector to avoid removals during iteration */
-    std::vector<CInode*> migrate;
-    migrate.assign(dist_ephemeral_pins.begin(), dist_ephemeral_pins.end());
-    for (auto& in : migrate) {
-      in->maybe_ephemeral_dist();
-    }
-    mds->balancer->handle_export_pins();
+    ephemeral_pin_config_changed = true;
   }
   if (changed.count("mds_export_ephemeral_random")) {
     export_ephemeral_random_config = g_conf().get_val<bool>("mds_export_ephemeral_random");
     dout(10) << "Migrating any ephemeral random pinned inodes" << dendl;
     /* copy to vector to avoid removals during iteration */
+    ephemeral_pin_config_changed = true;
+  }
+  if (ephemeral_pin_config_changed) {
     std::vector<CInode*> migrate;
-    migrate.assign(rand_ephemeral_pins.begin(), rand_ephemeral_pins.end());
+    migrate.assign(export_ephemeral_pins.begin(), export_ephemeral_pins.end());
     for (auto& in : migrate) {
-      in->maybe_ephemeral_rand();
+      in->maybe_export_pin(true);
     }
-    mds->balancer->handle_export_pins();
   }
   if (changed.count("mds_export_ephemeral_random_max")) {
     export_ephemeral_random_max = g_conf().get_val<double>("mds_export_ephemeral_random_max");
@@ -327,8 +326,6 @@ void MDCache::add_inode(CInode *in)
   if (cache_toofull()) {
     exceeded_size_limit = true;
   }
-
-  in->maybe_ephemeral_dist(false);
 }
 
 void MDCache::remove_inode(CInode *o) 
@@ -359,8 +356,7 @@ void MDCache::remove_inode(CInode *o)
   if (o->state_test(CInode::STATE_DELAYEDEXPORTPIN))
     export_pin_delayed_queue.erase(o);
 
-  o->set_ephemeral_dist(false);
-  o->set_ephemeral_rand(false);
+  o->clear_ephemeral_pin(true, true);
 
   // remove from inode map
   if (o->last == CEPH_NOSNAP) {
@@ -900,10 +896,13 @@ MDSCacheObject *MDCache::get_object(const MDSCacheObjectInfo &info)
 /*
  * hashing implementation based on Lamping and Veach's Jump Consistent Hash: https://arxiv.org/pdf/1406.2294.pdf
 */
-mds_rank_t MDCache::hash_into_rank_bucket(inodeno_t ino)
+mds_rank_t MDCache::hash_into_rank_bucket(inodeno_t ino, frag_t fg)
 {
   const mds_rank_t max_mds = mds->mdsmap->get_max_mds();
   uint64_t hash = rjhash64(ino);
+  if (fg)
+    hash = rjhash64(hash + rjhash64(fg.value()));
+
   int64_t b = -1, j = 0;
   while (j < max_mds) {
     b = j;
@@ -990,11 +989,6 @@ void MDCache::adjust_subtree_auth(CDir *dir, mds_authority_t auth, bool adjust_p
     }
   }
 
-  if (dir->is_auth()) {
-    /* do this now that we are auth for the CDir */
-    dir->inode->maybe_pin();
-  }
-
   show_subtrees();
 }
 
@@ -7848,22 +7842,6 @@ bool MDCache::shutdown_pass()
   trim(UINT64_MAX);
   dout(5) << "lru size now " << lru.lru_get_size() << "/" << bottom_lru.lru_get_size() << dendl;
 
-
-  {
-    dout(10) << "Migrating any ephemerally pinned inodes" << dendl;
-    /* copy to vector to avoid removals during iteration */
-    std::vector<CInode*> migrate;
-    migrate.assign(rand_ephemeral_pins.begin(), rand_ephemeral_pins.end());
-    for (auto& in : migrate) {
-      in->maybe_ephemeral_rand();
-    }
-    migrate.assign(dist_ephemeral_pins.begin(), dist_ephemeral_pins.end());
-    for (auto& in : migrate) {
-      in->maybe_ephemeral_dist();
-    }
-    mds->balancer->handle_export_pins();
-  }
-
   // Export all subtrees to another active (usually rank 0) if not rank 0
   int num_auth_subtree = 0;
   if (!subtrees.empty() && mds->get_nodeid() != 0) {
@@ -7885,7 +7863,8 @@ bool MDCache::shutdown_pass()
     }
 
     migrator->clear_export_queue();
-
+    // stopping mds does not call MDBalancer::tick()
+    mds->balancer->handle_export_pins();
     for (const auto& dir : ls) {
       mds_rank_t dest = dir->get_inode()->authority().first;
       if (dest > 0 && !mds->mdsmap->is_active(dest))
@@ -10847,7 +10826,7 @@ void MDCache::decode_replica_inode(CInode *&in, bufferlist::const_iterator& p, C
     s &= CInode::MASK_STATE_REPLICATED;
     if (s & CInode::STATE_RANDEPHEMERALPIN) {
       dout(10) << "replica inode is random ephemeral pinned" << dendl;
-      in->set_ephemeral_rand(true);
+      in->set_ephemeral_pin(false, true);
     }
   }
 
@@ -13239,16 +13218,15 @@ bool MDCache::dump_inode(Formatter *f, uint64_t number) {
 }
 
 void MDCache::handle_mdsmap(const MDSMap &mdsmap, const MDSMap &oldmap) {
+  const mds_rank_t max_mds = mdsmap.get_max_mds();
+
   // process export_pin_delayed_queue whenever a new MDSMap received
   auto &q = export_pin_delayed_queue;
   for (auto it = q.begin(); it != q.end(); ) {
     auto *in = *it;
     mds_rank_t export_pin = in->get_export_pin(false);
-    if (in->is_ephemerally_pinned()) {
-      dout(10) << "ephemeral export pin to " << export_pin << " for " << *in << dendl;
-    }
     dout(10) << " delayed export_pin=" << export_pin << " on " << *in 
-      << " max_mds=" << mdsmap.get_max_mds() << dendl;
+             << " max_mds=" << max_mds << dendl;
     if (export_pin >= mdsmap.get_max_mds()) {
       it++;
       continue;
@@ -13263,13 +13241,20 @@ void MDCache::handle_mdsmap(const MDSMap &mdsmap, const MDSMap &oldmap) {
     dout(10) << "Checking ephemerally pinned directories for redistribute due to max_mds change." << dendl;
     /* copy to vector to avoid removals during iteration */
     std::vector<CInode*> migrate;
-    migrate.assign(rand_ephemeral_pins.begin(), rand_ephemeral_pins.end());
-    for (auto& in : migrate) {
-      in->maybe_ephemeral_rand();
-    }
-    migrate.assign(dist_ephemeral_pins.begin(), dist_ephemeral_pins.end());
+    migrate.assign(export_ephemeral_pins.begin(), export_ephemeral_pins.end());
     for (auto& in : migrate) {
-      in->maybe_ephemeral_dist();
+      in->maybe_export_pin();
     }
   }
+
+  if (max_mds <= 1) {
+    export_ephemeral_dist_frag_bits = 0;
+  } else {
+    double want = g_conf().get_val<double>("mds_export_ephemeral_distributed_factor");
+    want *= max_mds;
+    unsigned n = 0;
+    while ((1U << n) < (unsigned)want)
+      ++n;
+    export_ephemeral_dist_frag_bits = n;
+  }
 }
diff --git a/src/mds/MDCache.h b/src/mds/MDCache.h
index 3dab7fba81cdc..8c0957646ad4e 100644
--- a/src/mds/MDCache.h
+++ b/src/mds/MDCache.h
@@ -212,6 +212,9 @@ class MDCache {
 
   void advance_stray();
 
+  unsigned get_ephemeral_dist_frag_bits() const {
+    return export_ephemeral_dist_frag_bits;
+  }
   bool get_export_ephemeral_distributed_config(void) const {
     return export_ephemeral_distributed_config;
   }
@@ -232,7 +235,7 @@ class MDCache {
     stray_manager.eval_stray(dn);
   }
 
-  mds_rank_t hash_into_rank_bucket(inodeno_t ino);
+  mds_rank_t hash_into_rank_bucket(inodeno_t ino, frag_t fg=0);
 
   void maybe_eval_stray(CInode *in, bool delay=false);
   void clear_dirty_bits_for_stray(CInode* diri);
@@ -991,8 +994,7 @@ class MDCache {
   /* Because exports may fail, this set lets us keep track of inodes that need exporting. */
   std::set<CInode *> export_pin_queue;
   std::set<CInode *> export_pin_delayed_queue;
-  std::set<CInode *> rand_ephemeral_pins;
-  std::set<CInode *> dist_ephemeral_pins;
+  std::set<CInode *> export_ephemeral_pins;
 
   OpenFileTable open_file_table;
 
@@ -1308,6 +1310,7 @@ class MDCache {
 
   bool export_ephemeral_distributed_config;
   bool export_ephemeral_random_config;
+  unsigned export_ephemeral_dist_frag_bits;
 
   // File size recovery
   RecoveryQueue recovery_queue;
diff --git a/src/mds/MDSRank.cc b/src/mds/MDSRank.cc
index 1811a1546cc39..faec88ceb9931 100644
--- a/src/mds/MDSRank.cc
+++ b/src/mds/MDSRank.cc
@@ -2944,11 +2944,13 @@ void MDSRank::command_get_subtrees(Formatter *f)
     {
       f->dump_bool("is_auth", dir->is_auth());
       f->dump_int("auth_first", dir->get_dir_auth().first);
-      f->dump_int("auth_second", dir->get_dir_auth().second);
-      f->dump_int("export_pin", dir->inode->get_export_pin(false, false));
-      f->dump_bool("distributed_ephemeral_pin", dir->inode->is_ephemeral_dist());
-      f->dump_bool("random_ephemeral_pin", dir->inode->is_ephemeral_rand());
-      f->dump_int("ephemeral_pin", mdcache->hash_into_rank_bucket(dir->inode->ino()));
+      f->dump_int("auth_second", dir->get_dir_auth().second); {
+	mds_rank_t export_pin = dir->inode->get_export_pin(false);
+	f->dump_int("export_pin", export_pin >= 0 ? export_pin : -1);
+	f->dump_bool("distributed_ephemeral_pin", export_pin == MDS_RANK_EPHEMERAL_DIST);
+	f->dump_bool("random_ephemeral_pin", export_pin == MDS_RANK_EPHEMERAL_RAND);
+      }
+      f->dump_int("export_pin_target", dir->get_export_pin(false));
       f->open_object_section("dir");
       dir->dump(f);
       f->close_section();
diff --git a/src/mds/Migrator.cc b/src/mds/Migrator.cc
index 9a6d90bf9bdf6..c6ee67b24dc72 100644
--- a/src/mds/Migrator.cc
+++ b/src/mds/Migrator.cc
@@ -790,7 +790,7 @@ void Migrator::export_dir(CDir *dir, mds_rank_t dest)
   ceph_assert(dest != mds->get_nodeid());
    
   CDir* parent = dir->inode->get_projected_parent_dir();
-  if (!mds->is_stopping() && !dir->inode->is_exportable(dest) && dir->get_num_head_items() > 0) {
+  if (!mds->is_stopping() && !dir->is_exportable(dest) && dir->get_num_head_items() > 0) {
     dout(7) << "Cannot export to mds." << dest << " " << *dir << ": dir is export pinned" << dendl;
     return;
   } else if (!(mds->is_active() || mds->is_stopping())) {
@@ -3472,7 +3472,6 @@ void Migrator::decode_import_dir(bufferlist::const_iterator& blp,
     dir->verify_fragstat();
 #endif
 
-  dir->inode->maybe_ephemeral_dist();
   dir->inode->maybe_export_pin();
 
   dout(7) << " done " << *dir << dendl;
diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index eb9e253c33fec..2cf9c7f611c4f 100644
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -6022,8 +6022,7 @@ public:
       get_mds()->locker->share_inode_max_size(newi);
     } else if (newi->is_dir()) {
       // We do this now so that the linkages on the new directory are stable.
-      newi->maybe_ephemeral_dist();
-      newi->maybe_ephemeral_rand(true);
+      newi->maybe_ephemeral_rand();
     }
 
     // hit pop
diff --git a/src/mds/journal.cc b/src/mds/journal.cc
index 61176a6007855..5f1253037cead 100644
--- a/src/mds/journal.cc
+++ b/src/mds/journal.cc
@@ -566,10 +566,8 @@ void EMetaBlob::fullbit::update_inode(MDSRank *mds, CInode *in)
   if (in->is_dir()) {
     if (is_export_ephemeral_random()) {
       dout(15) << "random ephemeral pin on " << *in << dendl;
-      in->set_ephemeral_rand(true);
-      in->maybe_ephemeral_rand(true);
+      in->set_ephemeral_pin(false, true);
     }
-    in->maybe_ephemeral_dist();
     in->maybe_export_pin();
     if (!(in->dirfragtree == dirfragtree)) {
       dout(10) << "EMetaBlob::fullbit::update_inode dft " << in->dirfragtree << " -> "
diff --git a/src/mds/mdstypes.h b/src/mds/mdstypes.h
index 9c4104fa6b963..736cceaa8133d 100644
--- a/src/mds/mdstypes.h
+++ b/src/mds/mdstypes.h
@@ -71,7 +71,9 @@
 #define MDS_INO_STRAY_INDEX(i) (((unsigned (i)) - MDS_INO_STRAY_OFFSET) % NUM_STRAY)
 
 typedef int32_t mds_rank_t;
-constexpr mds_rank_t MDS_RANK_NONE = -1;
+constexpr mds_rank_t MDS_RANK_NONE		= -1;
+constexpr mds_rank_t MDS_RANK_EPHEMERAL_DIST	= -2;
+constexpr mds_rank_t MDS_RANK_EPHEMERAL_RAND	= -3;
 
 BOOST_STRONG_TYPEDEF(uint64_t, mds_gid_t)
 extern const mds_gid_t MDS_GID_NONE;
-- 
2.39.5