From 0986fe9b50f425ec81f25a1a85aaf3574b31d801 Mon Sep 17 00:00:00 2001 From: Joseph Qi Date: Thu, 5 Nov 2015 18:44:07 -0800 Subject: [PATCH] ocfs2: fix race between mount and delete node/cluster There is a race case between mount and delete node/cluster, which will lead o2hb_thread to malfunctioning dead loop. o2hb_thread { o2nm_depend_this_node(); <<<<<< race window, node may have already been deleted, and then enter the loop, o2hb thread will be malfunctioning because of no configured nodes found. while (!kthread_should_stop() && !reg->hr_unclean_stop && !reg->hr_aborted_start) { } So check the return value of o2nm_depend_this_node() is needed. If node has been deleted, do not enter the loop and let mount fail. Signed-off-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/cluster/heartbeat.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c index fa15debcc02b..ddddef0021a0 100644 --- a/fs/ocfs2/cluster/heartbeat.c +++ b/fs/ocfs2/cluster/heartbeat.c @@ -219,7 +219,8 @@ struct o2hb_region { unsigned hr_unclean_stop:1, hr_aborted_start:1, hr_item_pinned:1, - hr_item_dropped:1; + hr_item_dropped:1, + hr_node_deleted:1; /* protected by the hr_callback_sem */ struct task_struct *hr_task; @@ -1078,7 +1079,13 @@ static int o2hb_thread(void *data) set_user_nice(current, MIN_NICE); /* Pin node */ - o2nm_depend_this_node(); + ret = o2nm_depend_this_node(); + if (ret) { + mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret); + reg->hr_node_deleted = 1; + wake_up(&o2hb_steady_queue); + return 0; + } while (!kthread_should_stop() && !reg->hr_unclean_stop && !reg->hr_aborted_start) { @@ -1787,7 +1794,8 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, spin_unlock(&o2hb_live_lock); ret = wait_event_interruptible(o2hb_steady_queue, - atomic_read(®->hr_steady_iterations) == 0); + atomic_read(®->hr_steady_iterations) == 0 || + reg->hr_node_deleted); if (ret) { atomic_set(®->hr_steady_iterations, 0); reg->hr_aborted_start = 1; @@ -1798,6 +1806,11 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg, goto out3; } + if (reg->hr_node_deleted) { + ret = -EINVAL; + goto out3; + } + /* Ok, we were woken. Make sure it wasn't by drop_item() */ spin_lock(&o2hb_live_lock); hb_task = reg->hr_task; -- GitLab