ocfs2: skip uninitialized lockres in ocfs2_mark_lockres_freeing()

A hard readonly mount skips ocfs2_dlm_init(), so the per-osb lock
resources are never initialized and osb->cconn stays NULL.  Before commit
550842cc60 ("ocfs2: fix freeing uninitialized resource on
ocfs2_dlm_shutdown") ocfs2_dismount_volume() only called
ocfs2_dlm_shutdown() when osb->cconn was set.  It now calls it
unconditionally, so unmounting a hard readonly mount drops the osb locks
and takes the never initialized l_lock in ocfs2_mark_lockres_freeing(). 
With lockdep enabled this triggers:

INFO: trying to register non-static key.  The code is fine but needs
lockdep annotation, or maybe you didn't initialize this object before use?
turning off the locking correctness validator.

ocfs2_drop_lock() and ocfs2_lock_res_free() already skip lock resources
without OCFS2_LOCK_INITIALIZED.  Add the same check to
ocfs2_mark_lockres_freeing(), which is reachable before them through
ocfs2_simple_drop_lockres(), so an uninitialized lockres is never touched.

Link: https://lore.kernel.org/20260903104744.2164235-1-joseph.qi@linux.alibaba.com
Fixes: 550842cc60 ("ocfs2: fix freeing uninitialized resource on ocfs2_dlm_shutdown")
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: ZW Tang <tangzw515@gmail.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Heming Zhao <heming.zhao@suse.com>
Cc: <stable@vger.kernel.org>

fs/ocfs2/dlmglue.c

@@ -3525,6 +3525,10 @@ void ocfs2_mark_lockres_freeing(struct ocfs2_super *osb,
 	struct ocfs2_mask_waiter mw;
 	unsigned long flags, flags2;
 
+	/* We didn't get anywhere near actually using this lockres. */
+	if (!(lockres->l_flags & OCFS2_LOCK_INITIALIZED))
+		return;
+
 	ocfs2_init_mask_waiter(&mw);
 
 	spin_lock_irqsave(&lockres->l_lock, flags);