From: Xiubo Li <xiubli@xxxxxxxxxx>
The possible max rank, it maybe larger than the m->m_num_mds,
for example if the mds_max == 2 in the cluster, when the MDS(0)
was laggy and being replaced by a new MDS, we will temporarily
receive a new mds map with n_num_mds == 1 and the active MDS(1),
and the mds rank >= m->m_num_mds.
Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx>
---
fs/ceph/mdsmap.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
index 284d68646c40..a77e0ecb9a6b 100644
--- a/fs/ceph/mdsmap.c
+++ b/fs/ceph/mdsmap.c
@@ -129,6 +129,7 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
int err;
u8 mdsmap_v, mdsmap_cv;
u16 mdsmap_ev;
+ u32 possible_max_rank;
m = kzalloc(sizeof(*m), GFP_NOFS);
if (!m)
@@ -164,6 +165,15 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
m->m_num_mds = n = ceph_decode_32(p);
m->m_num_active_mds = m->m_num_mds;
+ /*
+ * the possible max rank, it maybe larger than the m->m_num_mds,
+ * for example if the mds_max == 2 in the cluster, when the MDS(0)
+ * was laggy and being replaced by a new MDS, we will temporarily
+ * receive a new mds map with n_num_mds == 1 and the active MDS(1),
+ * and the mds rank >= m->m_num_mds.
+ */
+ possible_max_rank = max((u32)m->m_num_mds, m->m_max_mds);
+
m->m_info = kcalloc(m->m_num_mds, sizeof(*m->m_info), GFP_NOFS);
if (!m->m_info)
goto nomem;
@@ -238,7 +248,7 @@ struct ceph_mdsmap *ceph_mdsmap_decode(void **p, void *end)
ceph_mds_state_name(state),
laggy ? "(laggy)" : "");
- if (mds < 0 || mds >= m->m_num_mds) {
+ if (mds < 0 || mds >= possible_max_rank) {
pr_warn("mdsmap_decode got incorrect mds(%d)\n", mds);
continue;
}
--
2.21.0
