[Ocfs2-devel] [PATCH] ocfs2/cluster: unlock the o2hb_live_lock before the o2nm_depend_item()
alex chen
alex.chen at huawei.com
Tue Oct 31 05:41:39 PDT 2017
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 at huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen at huawei.com>
Reviewed-by: Jun Piao <piaojun at huawei.com>
---
fs/ocfs2/cluster/heartbeat.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index d020604..f1142a9 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -2399,6 +2399,9 @@ 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);
if (!ret) {
@@ -2410,9 +2413,14 @@ static int o2hb_region_pin(const char *region_uuid)
else {
mlog(ML_ERROR, "Pin region %s fails with %d\n",
uuid, ret);
+ config_item_put(®->hr_item);
+ spin_lock(&o2hb_live_lock);
break;
}
}
+
+ config_item_put(®->hr_item);
+ spin_lock(&o2hb_live_lock);
skip_pin:
if (found)
break;
-- 1.9.5.msysgit.1
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