From: Sage Weil <sage@redhat.com>
Date: Mon, 20 Apr 2015 19:48:38 +0000 (-0700)
Subject: os/newstore: a few comments about wal
X-Git-Tag: v9.1.0~242^2~53
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=e580a827290eb05b086b04591523345ee004ccae;p=ceph.git

os/newstore: a few comments about wal

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/os/newstore/NewStore.cc b/src/os/newstore/NewStore.cc
index 6cbbef8cbdd6..8dd10d6c5a9a 100644
--- a/src/os/newstore/NewStore.cc
+++ b/src/os/newstore/NewStore.cc
@@ -2420,13 +2420,19 @@ int NewStore::_do_wal_transaction(wal_transaction_t& wt)
 	       << cpp_strerror(r) << dendl;
 	  return r;
 	}
-	//sync_fds.push_back(fd);  // do we care?
+	// note: we are not syncing this truncate.  instead, we are
+	// careful about only reading as much of the fragment as we
+	// know is valid, and truncating to expected size before
+	// extending the file.
       }
       break;
 
     case wal_op_t::OP_REMOVE:
       dout(20) << __func__ << " remove " << p->fid << dendl;
       _remove_fid(p->fid);
+      // note: we do not fsync the directory.  instead, we tolerate
+      // leaked fragments in a crash.  in practice, this will be
+      // exceedingly rare.
       break;
 
     default: