From: Sage Weil <sage@redhat.com>
Date: Mon, 4 Aug 2014 07:01:54 -0700
Subject: libceph: gracefully handle large reply messages from the mon
Git-commit: 73c3d4812b4c755efeca0140f606f83772a39ce4
Patch-mainline: v3.17-rc5
References: FATE#318328 bsc#917884

We preallocate a few of the message types we get back from the mon.  If we
get a larger message than we are expecting, fall back to trying to allocate
a new one instead of blindly using the one we have.

CC: stable@vger.kernel.org
Signed-off-by: Sage Weil <sage@redhat.com>
Reviewed-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Acked-by: Lee Duncan <lduncan@suse.com> <lduncan@suse.com>
---
 net/ceph/mon_client.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/net/ceph/mon_client.c
+++ b/net/ceph/mon_client.c
@@ -1041,7 +1041,15 @@ static struct ceph_msg *mon_alloc_msg(st
 	if (!m) {
 		pr_info("alloc_msg unknown type %d\n", type);
 		*skip = 1;
+	} else if (front_len > m->front_alloc_len) {
+		pr_warning("mon_alloc_msg front %d > prealloc %d (%u#%llu)\n",
+			   front_len, m->front_alloc_len,
+			   (unsigned int)con->peer_name.type,
+			   le64_to_cpu(con->peer_name.num));
+		ceph_msg_put(m);
+		m = ceph_msg_new(type, front_len, GFP_NOFS, false);
 	}
+
 	return m;
 }
 
