cifs: wait for tcon resource_id before getting fscache super

The logic for initializing tcon->resource_id is done inside
cifs_root_iget. fscache super cookie relies on this for aux
data. So we need to push the fscache initialization to this
later point during mount.
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/connect.c

@@ -3046,12 +3046,6 @@ static int mount_get_conns(struct mount_ctx *mnt_ctx)
 				cifs_dbg(VFS, "read only mount of RW share\n");
 			/* no need to log a RW mount of a typical RW share */
 		}
-		/*
-		 * The cookie is initialized from volume info returned above.
-		 * Inside cifs_fscache_get_super_cookie it checks
-		 * that we do not get super cookie twice.
-		 */
-		cifs_fscache_get_super_cookie(tcon);
 	}
 
 	/*

fs/cifs/fscache.c

@@ -92,7 +92,7 @@ void cifs_fscache_get_super_cookie(struct cifs_tcon *tcon)
 	 * In the future, as we integrate with newer fscache features,
 	 * we may want to instead add a check if cookie has changed
 	 */
-	if (tcon->fscache == NULL)
+	if (tcon->fscache)
 		return;
 
 	sharename = extract_sharename(tcon->treeName);

fs/cifs/inode.c

@@ -1376,6 +1376,13 @@ struct inode *cifs_root_iget(struct super_block *sb)
 		inode = ERR_PTR(rc);
 	}
 
+	/*
+	 * The cookie is initialized from volume info returned above.
+	 * Inside cifs_fscache_get_super_cookie it checks
+	 * that we do not get super cookie twice.
+	 */
+	cifs_fscache_get_super_cookie(tcon);
+
 out:
 	kfree(path);
 	free_xid(xid);