ceph: fix bad pointer dereference in ceph_fill_trace

We dereference *in a few lines down, but only set it on rename.  It is
apparently pretty rare for this to trigger, but I have been hitting it
with a clustered MDSs.

Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 1d6a45b5a04c..cd0432c03d2f 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1055,7 +1055,8 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
                 ininfo = rinfo->targeti.in;
                 vino.ino = le64_to_cpu(ininfo->ino);
                 vino.snap = le64_to_cpu(ininfo->snapid);
-                if (!dn->d_inode) {
+                in = dn->d_inode;
+                if (!in) {
                         in = ceph_get_inode(sb, vino);
                         if (IS_ERR(in)) {
                                 pr_err("fill_trace bad get_inode "