client: more precise cap trimming

Two fixes:
 * Client would unlink everything it could, instead of just
   meeting its goal, because caps.size() doesn't change until
   dentries are cleaned up later.  Take account of the trimmed
   count in the while() condition to fix that.
 * Don't count the root ino as trimmed, as although it has no
   dentries (of course), we will never give up the cap.

With this change, the client will now precisely achieve the number
of caps requested in CEPH_SESSION_RECALL_STATE messages.

Signed-off-by: John Spray <john.spray@redhat.com>

diff --git a/src/client/Client.cc b/src/client/Client.cc
index d749dd05a3835977cc0ff50ca3f83f83a062089d..840b55257a94898169904fe1412dfb51da2d8b68 100644 (file)
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -3152,10 +3152,11 @@ void Client::trim_caps(MetaSession *s, int max)
 
   int trimmed = 0;
   xlist<Cap*>::iterator p = s->caps.begin();
-  while (s->caps.size() > max && !p.end()) {
+  while ((s->caps.size() - trimmed) > max && !p.end()) {
     Cap *cap = *p;
     s->s_cap_iterator = cap;
     Inode *in = cap->inode;
+
     if (in->caps.size() > 1 && cap != in->auth_cap) {
       int mine = cap->issued | cap->implemented;
       int oissued = in->auth_cap ? in->auth_cap->issued : 0;
@@ -3178,8 +3179,10 @@ void Client::trim_caps(MetaSession *s, int max)
          all = false;
         }
       }
-      if (all)
+      if (all && in->ino != MDS_INO_ROOT) {
+        ldout(cct, 20) << __func__ << " counting as trimmed: " << *in << dendl;
        trimmed++;
+      }
     }
 
     ++p;