ocfs2: kill EBUSY from dlmfs_evict_inode

When unlinking a dlmfs, first it will invoke dlmfs_unlink(), and then
invoke dlmfs_evict_inode(), user_dlm_destroy_lock() is invoked in both
places, the second one from dlmfs_evict_inode() will get EBUSY error
because USER_LOCK_IN_TEARDOWN is already set in lockres.  This doesn't
affect any function, just the error log is annoying.

Link: https://lkml.kernel.org/r/20220607171226.86672-1-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.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: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/dlmfs/dlmfs.c

@@ -296,17 +296,25 @@ static void dlmfs_evict_inode(struct inode *inode)
 {
 	int status;
 	struct dlmfs_inode_private *ip;
+	struct user_lock_res *lockres;
+	int teardown;
 
 	clear_inode(inode);
 
 	mlog(0, "inode %lu\n", inode->i_ino);
 
 	ip = DLMFS_I(inode);
+	lockres = &ip->ip_lockres;
 
 	if (S_ISREG(inode->i_mode)) {
-		status = user_dlm_destroy_lock(&ip->ip_lockres);
-		if (status < 0)
-			mlog_errno(status);
+		spin_lock(&lockres->l_lock);
+		teardown = !!(lockres->l_flags & USER_LOCK_IN_TEARDOWN);
+		spin_unlock(&lockres->l_lock);
+		if (!teardown) {
+			status = user_dlm_destroy_lock(lockres);
+			if (status < 0)
+				mlog_errno(status);
+		}
 		iput(ip->ip_parent);
 		goto clear_fields;
 	}