[PATCH 3.13 047/163] libceph: gracefully handle large reply messages from the mon

From: Kamal Mostafa
Date: Thu Oct 09 2014 - 17:08:15 EST -stable review patch. If anyone has any objections, please let me know.


From: Sage Weil <sage@xxxxxxxxxx>

commit 73c3d4812b4c755efeca0140f606f83772a39ce4 upstream.

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.

Signed-off-by: Sage Weil <sage@xxxxxxxxxx>
Reviewed-by: Ilya Dryomov <ilya.dryomov@xxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
net/ceph/mon_client.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
index 2ac9ef3..dbcbf5a 100644
--- a/net/ceph/mon_client.c
+++ b/net/ceph/mon_client.c
@@ -1041,7 +1041,15 @@ static struct ceph_msg *mon_alloc_msg(struct ceph_connection *con,
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;


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