mds: avoid journal unnessary dirfrags in ESubtreeMap

EMetaBlob::add_dir_contex() skips adding inodes that has already
been journaled in the last ESubtreeMap. The log replay code only
replays the first ESubtreeMap. For the rest ESubtreeMap, it just
verifies subtree map in the cache matches the ESubtreeMap. If
unnessary inodes were included in non-first ESubtreeMap, these
inodes do not get added to the cache, the log replay code can
find these inodes are missing when replaying the rest events in
the log segment.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index 3beae2ea7a12299bfc6897563e16ebb40d695470..8f278fdde8d44d0e7ef579f90bfdce86ac6675bc 100644 (file)
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -2506,6 +2506,8 @@ ESubtreeMap *MDCache::create_subtree_map()
     mydir = myin->get_dirfrag(frag_t());
   }
 
+  list<CDir*> maybe;
+
   // include all auth subtrees, and their bounds.
   // and a spanning tree to tie it to the root.
   for (map<CDir*, set<CDir*> >::iterator p = subtrees.begin();
@@ -2532,6 +2534,15 @@ ESubtreeMap *MDCache::create_subtree_map()
     }
 
     le->subtrees[dir->dirfrag()].clear();
+
+    if (dir->get_dir_auth().second != CDIR_AUTH_UNKNOWN &&
+       le->ambiguous_subtrees.count(dir->dirfrag()) == 0 &&
+       p->second.empty()) {
+      dout(10) << " maybe journal " << *dir << dendl;
+      maybe.push_back(dir);
+      continue;
+    }
+
     le->metablob.add_dir_context(dir, EMetaBlob::TO_ROOT);
     le->metablob.add_dir(dir, false);
 
@@ -2643,6 +2654,18 @@ ESubtreeMap *MDCache::create_subtree_map()
       }
     }
   }
+
+  for (list<CDir*>::iterator p = maybe.begin(); p != maybe.end(); ++p) {
+    CDir *dir = *p;
+    if (le->subtrees.count(dir->dirfrag())) {
+      // not swallowed by above code
+      le->metablob.add_dir_context(dir, EMetaBlob::TO_ROOT);
+      le->metablob.add_dir(dir, false);
+    } else {
+      dout(10) << "simplify: not journal " << *dir << dendl;
+    }
+  }
+
   dout(15) << " subtrees " << le->subtrees << dendl;
   dout(15) << " ambiguous_subtrees " << le->ambiguous_subtrees << dendl;