From: Sage Weil <sage@newdream.net>
Date: Thu, 3 Dec 2009 23:16:08 +0000 (-0800)
Subject: mds: avoid scatter writebehind from predirty_*
X-Git-Tag: v0.18~2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=dc2435118762bb4531407641217d055e7962a56a;p=ceph.git

mds: avoid scatter writebehind from predirty_*

predirty_journal_parents does wrlock_start with
nowait=true.  Make sure we don't then simple_lock if
lock->is_updated(), as that will call scatter_writebehind,
which will barf if a log event is currently open (which
it is in this case).
---

diff --git a/src/mds/Locker.cc b/src/mds/Locker.cc
index b3f29089f19a..9f31eb461f41 100644
--- a/src/mds/Locker.cc
+++ b/src/mds/Locker.cc
@@ -813,8 +813,11 @@ bool Locker::wrlock_start(SimpleLock *lock, MDRequest *mut, bool nowait)
     if (in->is_auth()) {
       if (want_scatter)
 	file_mixed((ScatterLock*)lock);
-      else 
+      else {
+	if (nowait && lock->is_updated())
+	  return false;   // don't do nested lock, as that may scatter_writebehind in simple_lock!
 	simple_lock(lock);
+      }
 
       if (nowait && !lock->can_wrlock(client))
 	return false;