ceph: tolerate (and warn on) extraneous dentry from mds

If the MDS gives us a dentry and we weren't prepared to handle it,
WARN_ON_ONCE instead of crashing.

Reported-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 9fff9f3..4b5762e 100644 (file)
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -992,11 +992,15 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
        if (rinfo->head->is_dentry) {
                struct inode *dir = req->r_locked_dir;
 
-               err = fill_inode(dir, &rinfo->diri, rinfo->dirfrag,
-                                session, req->r_request_started, -1,
-                                &req->r_caps_reservation);
-               if (err < 0)
-                       return err;
+               if (dir) {
+                       err = fill_inode(dir, &rinfo->diri, rinfo->dirfrag,
+                                        session, req->r_request_started, -1,
+                                        &req->r_caps_reservation);
+                       if (err < 0)
+                               return err;
+               } else {
+                       WARN_ON_ONCE(1);
+               }
        }
 
        /*
@@ -1004,6 +1008,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
         * will have trouble splicing in the virtual snapdir later
         */
        if (rinfo->head->is_dentry && !req->r_aborted &&
+           req->r_locked_dir &&
            (rinfo->head->is_target || strncmp(req->r_dentry->d_name.name,
                                               fsc->mount_options->snapdir_name,
                                               req->r_dentry->d_name.len))) {