From: alex chen <alex.chen@huawei.com>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [PATCH v2] ocfs2/cluster: unlock the o2hb_live_lock before the o2nm_depend_item()
Date: Thu, 2 Nov 2017 14:00:12 +0800 [thread overview]
Message-ID: <59FAB46C.9050703@huawei.com> (raw)
In the following situation, the down_write() will be called under
the spin_lock(), which may lead a soft lockup:
o2hb_region_inc_user
spin_lock(&o2hb_live_lock)
o2hb_region_pin
o2nm_depend_item
configfs_depend_item
inode_lock
down_write
-->here may sleep and reschedule
So we should unlock the o2hb_live_lock before the o2nm_depend_item(), and
get item reference in advance to prevent the region to be released.
Signed-off-by: Alex Chen <alex.chen@huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: Jun Piao <piaojun@huawei.com>
---
fs/ocfs2/cluster/heartbeat.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index d020604..07b2fdc 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -2399,8 +2399,15 @@ static int o2hb_region_pin(const char *region_uuid)
if (reg->hr_item_pinned || reg->hr_item_dropped)
goto skip_pin;
+ config_item_get(®->hr_item);
+ spin_unlock(&o2hb_live_lock);
+
/* Ignore ENOENT only for local hb (userdlm domain) */
ret = o2nm_depend_item(®->hr_item);
+
+ config_item_put(®->hr_item);
+ spin_lock(&o2hb_live_lock);
+
if (!ret) {
mlog(ML_CLUSTER, "Pin region %s\n", uuid);
reg->hr_item_pinned = 1;
--
1.9.5.msysgit.1
next reply other threads:[~2017-11-02 6:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-02 6:00 alex chen [this message]
2017-11-06 9:37 ` [Ocfs2-devel] [PATCH v2] ocfs2/cluster: unlock the o2hb_live_lock before the o2nm_depend_item() Joseph Qi
2017-11-07 2:30 ` alex chen
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