ceph: d_alloc_root() may fail

... and ceph_init_dentry(NULL) will oops

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 11 insertions, 4 deletions

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 11bd0fc4853f..48f61a12af66 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -636,19 +636,26 @@ static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
         req->r_num_caps = 2;
         err = ceph_mdsc_do_request(mdsc, NULL, req);
         if (err == 0) {
+                struct inode *inode = req->r_target_inode;
+                req->r_target_inode = NULL;
                 dout("open_root_inode success\n");
-                if (ceph_ino(req->r_target_inode) == CEPH_INO_ROOT &&
+                if (ceph_ino(inode) == CEPH_INO_ROOT &&
                     fsc->sb->s_root == NULL) {
-                        root = d_alloc_root(req->r_target_inode);
+                        root = d_alloc_root(inode);
+                        if (!root) {
+                                iput(inode);
+                                root = ERR_PTR(-ENOMEM);
+                                goto out;
+                        }
                         ceph_init_dentry(root);
                 } else {
-                        root = d_obtain_alias(req->r_target_inode);
+                        root = d_obtain_alias(inode);
                 }
-                req->r_target_inode = NULL;
                 dout("open_root_inode success, root dentry is %p\n", root);
         } else {
                 root = ERR_PTR(err);
         }
+out:
         ceph_mdsc_put_request(req);
         return root;
 }