mds: Avoid creating unnecessary snaprealm

When moving directory between snaprealms, we can avoid creating snaprealm
if the directory doesn't has its own snaprealm and directory was created
after both realms' newest snapshot.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>

diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index e16800ecebc69326437c18b70c881675fa675c6f..b706b5abf81ba24889c69f902e6757bb289a0638 100644 (file)
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -4577,7 +4577,8 @@ void Server::_unlink_local(MDRequest *mdr, CDentry *dn, CDentry *straydn)
     mdcache->predirty_journal_parents(mdr, &le->metablob, in, straydn->get_dir(), PREDIRTY_PRIMARY|PREDIRTY_DIR, 1);
 
     // project snaprealm, too
-    in->project_past_snaprealm_parent(straydn->get_dir()->inode->find_snaprealm());
+    if (in->snaprealm || follows + 1 > dn->first)
+      in->project_past_snaprealm_parent(straydn->get_dir()->inode->find_snaprealm());
 
     le->metablob.add_primary_dentry(straydn, true, in);
   } else {
@@ -5247,11 +5248,16 @@ void Server::handle_client_rename(MDRequest *mdr)
   }
 
   // moving between snaprealms?
-  if (srcdnl->is_primary() && !srci->snaprealm &&
-      srci->find_snaprealm() != destdn->get_dir()->inode->find_snaprealm()) {
-    dout(10) << " renaming between snaprealms, creating snaprealm for " << *srci << dendl;
-    mds->mdcache->snaprealm_create(mdr, srci);
-    return;
+  if (srcdnl->is_primary() && srci->is_multiversion() && !srci->snaprealm) {
+    SnapRealm *srcrealm = srci->find_snaprealm();
+    SnapRealm *destrealm = destdn->get_dir()->inode->find_snaprealm();
+    if (srcrealm != destrealm &&
+       (srcrealm->get_newest_seq() + 1 > srcdn->first ||
+        destrealm->get_newest_seq() + 1 > srcdn->first)) {
+      dout(10) << " renaming between snaprealms, creating snaprealm for " << *srci << dendl;
+      mds->mdcache->snaprealm_create(mdr, srci);
+      return;
+    }
   }
 
   assert(g_conf->mds_kill_rename_at != 1);
@@ -5650,6 +5656,7 @@ void Server::_rename_prepare(MDRequest *mdr,
   if (destdn->is_auth())
     mdcache->predirty_journal_parents(mdr, metablob, srci, destdn->get_dir(), flags, 1);
 
+  SnapRealm *src_realm = srci->find_snaprealm();
   SnapRealm *dest_realm = destdn->get_dir()->inode->find_snaprealm();
   snapid_t next_dest_snap = dest_realm->get_newest_seq() + 1;
 
@@ -5659,7 +5666,8 @@ void Server::_rename_prepare(MDRequest *mdr,
     if (destdnl->is_primary()) {
       if (destdn->is_auth()) {
        // project snaprealm, too
-       oldin->project_past_snaprealm_parent(straydn->get_dir()->inode->find_snaprealm());
+       if (oldin->snaprealm || src_realm->get_newest_seq() + 1 > srcdn->first)
+         oldin->project_past_snaprealm_parent(straydn->get_dir()->inode->find_snaprealm());
        straydn->first = MAX(oldin->first, next_dest_snap);
        metablob->add_primary_dentry(straydn, true, oldin);
       }
@@ -5703,7 +5711,8 @@ void Server::_rename_prepare(MDRequest *mdr,
     }
   } else if (srcdnl->is_primary()) {
     // project snap parent update?
-    if (destdn->is_auth() && srci->snaprealm)
+    if (destdn->is_auth() &&
+        (srci->snaprealm || src_realm->get_newest_seq() + 1 > srcdn->first))
       srci->project_past_snaprealm_parent(dest_realm);
     
     if (destdn->is_auth() && !destdnl->is_null())