This is v1 version, I sent out V2 patch set before to fix all code style
issue.

On 03/24/2016 04:12 AM, a...@linux-foundation.org wrote:
> From: Junxiao Bi <junxiao...@oracle.com>
> Subject: ocfs2: o2hb: add negotiate timer
> 
> This series of patches is to fix the issue that when storage down, all
> nodes will fence self due to write timeout.
> 
> With this patch set, all nodes will keep going until storage back online,
> except if the following issue happens, then all nodes will do as before to
> fence self.
> 
> 1. io error got
> 2. network between nodes down
> 3. nodes panic
> 
> 
> This patch (of 6):
> 
> When storage down, all nodes will fence self due to write timeout.  The
> negotiate timer is designed to avoid this, with it node will wait until
> storage up again.
> 
> Negotiate timer working in the following way:
> 
> 1. The timer expires before write timeout timer, its timeout is half
>    of write timeout now.  It is re-queued along with write timeout timer. 
>    If expires, it will send NEGO_TIMEOUT message to master node(node with
>    lowest node number).  This message does nothing but marks a bit in a
>    bitmap recording which nodes are negotiating timeout on master node.
> 
> 2. If storage down, nodes will send this message to master node, then
>    when master node finds its bitmap including all online nodes, it sends
>    NEGO_APPROVL message to all nodes one by one, this message will
>    re-queue write timeout timer and negotiate timer.  For any node doesn't
>    receive this message or meets some issue when handling this message, it
>    will be fenced.  If storage up at any time, o2hb_thread will run and
>    re-queue all the timer, nothing will be affected by these two steps.
> 
> Signed-off-by: Junxiao Bi <junxiao...@oracle.com>
> Reviewed-by: Ryan Ding <ryan.d...@oracle.com>
> Cc: Gang He <g...@suse.com>
> Cc: rwxybh <rwx...@126.com>
> Cc: Mark Fasheh <mfas...@suse.de>
> Cc: Joel Becker <jl...@evilplan.org>
> Cc: Joseph Qi <joseph...@huawei.com>
> Signed-off-by: Andrew Morton <a...@linux-foundation.org>
> ---
> 
>  fs/ocfs2/cluster/heartbeat.c |   52 ++++++++++++++++++++++++++++++---
>  1 file changed, 48 insertions(+), 4 deletions(-)
> 
> diff -puN fs/ocfs2/cluster/heartbeat.c~ocfs2-o2hb-add-negotiate-timer 
> fs/ocfs2/cluster/heartbeat.c
> --- a/fs/ocfs2/cluster/heartbeat.c~ocfs2-o2hb-add-negotiate-timer
> +++ a/fs/ocfs2/cluster/heartbeat.c
> @@ -272,6 +272,10 @@ struct o2hb_region {
>       struct delayed_work     hr_write_timeout_work;
>       unsigned long           hr_last_timeout_start;
>  
> +     /* negotiate timer, used to negotiate extending hb timeout. */
> +     struct delayed_work     hr_nego_timeout_work;
> +     unsigned long           
> hr_nego_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
> +
>       /* Used during o2hb_check_slot to hold a copy of the block
>        * being checked because we temporarily have to zero out the
>        * crc field. */
> @@ -319,7 +323,7 @@ static void o2hb_write_timeout(struct wo
>       o2quo_disk_timeout();
>  }
>  
> -static void o2hb_arm_write_timeout(struct o2hb_region *reg)
> +static void o2hb_arm_timeout(struct o2hb_region *reg)
>  {
>       /* Arm writeout only after thread reaches steady state */
>       if (atomic_read(&reg->hr_steady_iterations) != 0)
> @@ -337,11 +341,50 @@ static void o2hb_arm_write_timeout(struc
>       reg->hr_last_timeout_start = jiffies;
>       schedule_delayed_work(&reg->hr_write_timeout_work,
>                             msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
> +
> +     cancel_delayed_work(&reg->hr_nego_timeout_work);
> +     /* negotiate timeout must be less than write timeout. */
> +     schedule_delayed_work(&reg->hr_nego_timeout_work,
> +                           msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS)/2);
> +     memset(reg->hr_nego_node_bitmap, 0, sizeof(reg->hr_nego_node_bitmap));
>  }
>  
> -static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
> +static void o2hb_disarm_timeout(struct o2hb_region *reg)
>  {
>       cancel_delayed_work_sync(&reg->hr_write_timeout_work);
> +     cancel_delayed_work_sync(&reg->hr_nego_timeout_work);
> +}
> +
> +static void o2hb_nego_timeout(struct work_struct *work)
> +{
> +     struct o2hb_region *reg =
> +             container_of(work, struct o2hb_region,
> +                          hr_nego_timeout_work.work);
> +     unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
> +     int master_node;
> +
> +     o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
> +     /* lowest node as master node to make negotiate decision. */
> +     master_node = find_next_bit(live_node_bitmap, O2NM_MAX_NODES, 0);
> +
> +     if (master_node == o2nm_this_node()) {
> +             set_bit(master_node, reg->hr_nego_node_bitmap);
> +             if (memcmp(reg->hr_nego_node_bitmap, live_node_bitmap,
> +                             sizeof(reg->hr_nego_node_bitmap))) {
> +                     /* check negotiate bitmap every second to do timeout
> +                      * approve decision.
> +                      */
> +                     schedule_delayed_work(&reg->hr_nego_timeout_work,
> +                             msecs_to_jiffies(1000));
> +
> +                     return;
> +             }
> +
> +             /* approve negotiate timeout request. */
> +     } else {
> +             /* negotiate timeout with master node. */
> +     }
> +
>  }
>  
>  static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
> @@ -1032,7 +1075,7 @@ static int o2hb_do_disk_heartbeat(struct
>       /* Skip disarming the timeout if own slot has stale/bad data */
>       if (own_slot_ok) {
>               o2hb_set_quorum_device(reg);
> -             o2hb_arm_write_timeout(reg);
> +             o2hb_arm_timeout(reg);
>       }
>  
>  bail:
> @@ -1114,7 +1157,7 @@ static int o2hb_thread(void *data)
>               }
>       }
>  
> -     o2hb_disarm_write_timeout(reg);
> +     o2hb_disarm_timeout(reg);
>  
>       /* unclean stop is only used in very bad situation */
>       for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
> @@ -1763,6 +1806,7 @@ static ssize_t o2hb_region_dev_store(str
>       }
>  
>       INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
> +     INIT_DELAYED_WORK(&reg->hr_nego_timeout_work, o2hb_nego_timeout);
>  
>       /*
>        * A node is considered live after it has beat LIVE_THRESHOLD
> _
> 


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