ceph: d_alloc_root() may fail

... and ceph_init_dentry(NULL) will oops

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

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 11bd0fc4853fbbcbbceb3b2b1cd424a16d17de32..48f61a12af66eecdd57f792c2b5da44d5c86468f 100644 (file)
--- 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;
 }