diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index e85b1ccf81be..77b8f0363e94 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -311,11 +311,25 @@ int ocfs2_lock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
 	spin_unlock(&dq_data_lock);
 	if (ex) {
 		inode_lock(oinfo->dqi_gqinode);
-		down_write(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
+		if (!down_write_trylock(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem)) {
+			inode_unlock(oinfo->dqi_gqinode);
+			status = -EBUSY;
+			goto bail;
+		}
 	} else {
 		down_read(&OCFS2_I(oinfo->dqi_gqinode)->ip_alloc_sem);
 	}
 	return 0;
+
+bail:
+	/* does a similar job as ocfs2_unlock_global_qf */
+	ocfs2_inode_unlock(oinfo->dqi_gqinode, ex);
+	brelse(oinfo->dqi_gqi_bh);
+	spin_lock(&dq_data_lock);
+	if (!--oinfo->dqi_gqi_count)
+		oinfo->dqi_gqi_bh = NULL;
+	spin_unlock(&dq_data_lock);
+	return status;
 }
 
 void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index c4e0117d8977..e749cd064c87 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -1224,7 +1224,9 @@ int ocfs2_create_local_dquot(struct dquot *dquot)
 	int status;
 	u64 pcount;
 
-	down_write(&OCFS2_I(lqinode)->ip_alloc_sem);
+	if (!down_write_trylock(&OCFS2_I(lqinode)->ip_alloc_sem))
+		return -EBUSY;
+
 	chunk = ocfs2_find_free_entry(sb, type, &offset);
 	if (!chunk) {
 		chunk = ocfs2_extend_local_quota_file(sb, type, &offset);