GFS2: let spectator mount do read only recovery

Previously, a spectator mount would not even attempt to do
journal recovery for a failed node.  This meant that if all
mounted nodes were spectators, everyone would be stuck after
a node failed, all waiting for recovery to be performed.
This is unnecessary since the failed node had a clean journal.

Instead, allow a spectator mount to do a partial "read only"
recovery, which means it will check if the failed journal is
clean, and if so, report a successful recovery.  If the failed
journal is not clean, it reports that journal recovery failed.
This makes it work the same as a read only mount on a read only
block device.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index af49e8f..80701d1 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -516,7 +516,9 @@
 		if (error)
 			goto fail_gunlock_ji;
 
-		if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
+		if (test_bit(SDF_RORECOVERY, &sdp->sd_flags)) {
+			ro = 1;
+		} else if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
 			if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
 				ro = 1;
 		} else {