From: Henrik Korkuc <henrik@uber.com>
Date: Sun, 19 Feb 2017 09:44:20 +0000 (+0200)
Subject: client/Client.cc: add feature to reconnect client after MDS reset
X-Git-Tag: v10.2.8~37^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=5b562145197833c6a6f48f006dfb13b6e38f9084;p=ceph.git

client/Client.cc: add feature to reconnect client after MDS reset

Client.cc marks session as stale instead of reconecting after received
reset from MDS. On MDS side session is closed so MDS is ignoring cap
renew. This adds option to reconnect stale client sessions instead of
just marking sessions stale.

Fixes: http://tracker.ceph.com/issues/18757

Signed-off-by: Henrik Korkuc <henrik@kirneh.eu>
(cherry picked from commit e0bbc704676ef4aed510daff075ef63c9e73b7b3)
---

diff --git a/doc/cephfs/client-config-ref.rst b/doc/cephfs/client-config-ref.rst
index a789a6d4d16c..ce5562fae406 100644
--- a/doc/cephfs/client-config-ref.rst
+++ b/doc/cephfs/client-config-ref.rst
@@ -147,6 +147,12 @@
 :Type: Integer
 :Default: ``131072`` (128KB)
 
+``client_reconnect_stale``
+
+:Description: Automatically reconnect stale session.
+:Type: Boolean
+:Default: ``false``
+
 ``client_snapdir``
 
 :Description: Set the snapshot directory name.
diff --git a/src/client/Client.cc b/src/client/Client.cc
index 2d3284b76dce..59bba676d9bf 100644
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -12059,8 +12059,16 @@ void Client::ms_handle_remote_reset(Connection *con)
 	  break;
 
 	case MetaSession::STATE_OPEN:
-	  ldout(cct, 1) << "reset from mds we were open; mark session as stale" << dendl;
-	  s->state = MetaSession::STATE_STALE;
+	  {
+	    const md_config_t *conf = cct->_conf;
+	    if (conf->client_reconnect_stale) {
+	      ldout(cct, 1) << "reset from mds we were open; close mds session for reconnect" << dendl;
+	      _closed_mds_session(s);
+	    } else {
+	      ldout(cct, 1) << "reset from mds we were open; mark session as stale" << dendl;
+	      s->state = MetaSession::STATE_STALE;
+	    }
+	  }
 	  break;
 
 	case MetaSession::STATE_NEW:
diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index 4eafaf7d4213..ca9141c6be04 100644
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -375,6 +375,7 @@ OPTION(client_trace, OPT_STR, "")
 OPTION(client_readahead_min, OPT_LONGLONG, 128*1024)  // readahead at _least_ this much.
 OPTION(client_readahead_max_bytes, OPT_LONGLONG, 0)  // default unlimited
 OPTION(client_readahead_max_periods, OPT_LONGLONG, 4)  // as multiple of file layout period (object size * num stripes)
+OPTION(client_reconnect_stale, OPT_BOOL, false)  // automatically reconnect stale session
 OPTION(client_snapdir, OPT_STR, ".snap")
 OPTION(client_mountpoint, OPT_STR, "/")
 OPTION(client_mount_uid, OPT_INT, -1)