nautilus: cephfs: mds: cleanup unneeded client_snap_caps when splitting snap inode

src/mds/CInode.cc

@@ -335,23 +335,28 @@ void CInode::remove_need_snapflush(CInode *snapin, snapid_t snapid, client_t cli
   }
 }
 
-bool CInode::split_need_snapflush(CInode *cowin, CInode *in)
+pair<bool,bool> CInode::split_need_snapflush(CInode *cowin, CInode *in)
 {
   dout(10) << __func__ << " [" << cowin->first << "," << cowin->last << "] for " << *cowin << dendl;
-  bool need_flush = false;
-  for (auto it = client_need_snapflush.lower_bound(cowin->first);
-       it != client_need_snapflush.end() && it->first < in->first; ) {
+  bool cowin_need_flush = false;
+  bool orig_need_flush = false;
+  auto it = client_need_snapflush.lower_bound(cowin->first);
+  while (it != client_need_snapflush.end() && it->first < in->first) {
     ceph_assert(!it->second.empty());
     if (cowin->last >= it->first) {
       cowin->auth_pin(this);
-      need_flush = true;
+      cowin_need_flush = true;
       ++it;
     } else {
       it = client_need_snapflush.erase(it);
     }
     in->auth_unpin(this);
   }
-  return need_flush;
+
+  if (it != client_need_snapflush.end() && it->first <= in->last)
+    orig_need_flush = true;
+
+  return make_pair(cowin_need_flush, orig_need_flush);
 }
 
 void CInode::mark_dirty_rstat()

src/mds/CInode.h

@@ -631,7 +631,7 @@ class CInode : public MDSCacheObject, public InodeStoreBase, public Counter<CIno
 
   void add_need_snapflush(CInode *snapin, snapid_t snapid, client_t client);
   void remove_need_snapflush(CInode *snapin, snapid_t snapid, client_t client);
-  bool split_need_snapflush(CInode *cowin, CInode *in);
+  pair<bool,bool> split_need_snapflush(CInode *cowin, CInode *in);
 
 protected:
 

src/mds/MDCache.cc

@@ -1465,19 +1465,41 @@ CInode *MDCache::cow_inode(CInode *in, snapid_t last)
   if (in->last != CEPH_NOSNAP) {
     CInode *head_in = get_inode(in->ino());
     ceph_assert(head_in);
-    if (head_in->split_need_snapflush(oldin, in)) {
+    auto ret = head_in->split_need_snapflush(oldin, in);
+    if (ret.first) {
       oldin->client_snap_caps = in->client_snap_caps;
-      for (const auto &p : in->client_snap_caps) {
+      for (const auto &p : oldin->client_snap_caps) {
 	SimpleLock *lock = oldin->get_lock(p.first);
 	ceph_assert(lock);
 	for (const auto &q : p.second) {
-	  oldin->auth_pin(lock);
-	  lock->set_state(LOCK_SNAP_SYNC);  // gathering
+	  if (lock->get_state() != LOCK_SNAP_SYNC) {
+	    ceph_assert(lock->is_stable());
+	    lock->set_state(LOCK_SNAP_SYNC);  // gathering
+	    oldin->auth_pin(lock);
+	  }
 	  lock->get_wrlock(true);
-          (void)q; /* unused */
+	  (void)q; /* unused */
 	}
       }
     }
+    if (!ret.second) {
+      auto client_snap_caps = std::move(in->client_snap_caps);
+      in->client_snap_caps.clear();
+      in->item_open_file.remove_myself();
+      in->item_caps.remove_myself();
+      for (const auto &p : client_snap_caps) {
+	SimpleLock *lock = in->get_lock(p.first);
+	ceph_assert(lock);
+	ceph_assert(lock->get_state() == LOCK_SNAP_SYNC); // gathering
+	for (const auto &q : p.second) {
+	  lock->put_wrlock();
+	  (void)q; /* unused */
+	}
+	ceph_assert(!lock->get_num_wrlocks());
+	lock->set_state(LOCK_SYNC);
+	in->auth_unpin(lock);
+      }
+    }
     return oldin;
   }
 
@@ -1496,10 +1518,13 @@ CInode *MDCache::cow_inode(CInode *in, snapid_t last)
 	    int lockid = cinode_lock_info[i].lock;
 	    SimpleLock *lock = oldin->get_lock(lockid);
 	    ceph_assert(lock);
-	    oldin->client_snap_caps[lockid].insert(client);
-	    oldin->auth_pin(lock);
-	    lock->set_state(LOCK_SNAP_SYNC);  // gathering
+	    if (lock->get_state() != LOCK_SNAP_SYNC) {
+	      ceph_assert(lock->is_stable());
+	      lock->set_state(LOCK_SNAP_SYNC);  // gathering
+	      oldin->auth_pin(lock);
+	    }
 	    lock->get_wrlock(true);
+	    oldin->client_snap_caps[lockid].insert(client);
 	    dout(10) << " client." << client << " cap " << ccap_string(issued & cinode_lock_info[i].wr_caps)
 		     << " wrlock lock " << *lock << " on " << *oldin << dendl;
 	  }