Hi Joseph,
On 09/17/2015 09:17 PM, Joseph Qi wrote:
> There is a race window between dlmconvert_remote and
> dlm_move_lockres_to_recovery_list, which will cause a lock with
> OCFS2_LOCK_BUSY in grant list, thus system hangs.
>
> dlmconvert_remote
> {
> spin_lock(&res->spinlock);
> list_move_tail(&lock->list, &res->converting);
> lock->convert_pending = 1;
> spin_unlock(&res->spinlock);
>
> status = dlm_send_remote_convert_request();
> >>>>>> race window, master has queued ast and return DLM_NORMAL,
> and then down before sending ast.
> this node detects master down and call
> dlm_move_lockres_to_recovery_list, which will revert the
> lock to grant list.
> Then OCFS2_LOCK_BUSY won't be cleared as new master won't
> send ast any more because it thinks already be authorized.
>
> spin_lock(&res->spinlock);
> lock->convert_pending = 0;
> if (status != DLM_NORMAL)
> dlm_revert_pending_convert(res, lock);
> spin_unlock(&res->spinlock);
> }
>
> In this case, just leave it in convert list and new master will take
> care of it after recovery. And if convert request returns other than
> DLM_NORMAL, convert thread will do the revert itself.
> So remove the revert logic in dlm_move_lockres_to_recovery_list.
Yes, looks good. The lock was already in convert list. Recovery process
will shuffle the list and send ast again. So why not clean up
convert_pending, it is useless now?
The same thing happen for lock_pending, the lock was already in block
list. I think it can also be removed.
Thanks,
Junxiao.
>
> Reported-by: Yiwen Jiang <jiangyi...@huawei.com>
> Signed-off-by: Joseph Qi <joseph...@huawei.com>
> Cc: <sta...@vger.kernel.org>
> ---
> fs/ocfs2/dlm/dlmrecovery.c | 10 +---------
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
> index ce12e0b..d797d49 100644
> --- a/fs/ocfs2/dlm/dlmrecovery.c
> +++ b/fs/ocfs2/dlm/dlmrecovery.c
> @@ -2058,15 +2058,7 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt
> *dlm,
> queue = dlm_list_idx_to_ptr(res, i);
> list_for_each_entry_safe(lock, next, queue, list) {
> dlm_lock_get(lock);
> - if (lock->convert_pending) {
> - /* move converting lock back to granted */
> - BUG_ON(i != DLM_CONVERTING_LIST);
> - mlog(0, "node died with convert pending "
> - "on %.*s. move back to granted list.\n",
> - res->lockname.len, res->lockname.name);
> - dlm_revert_pending_convert(res, lock);
> - lock->convert_pending = 0;
> - } else if (lock->lock_pending) {
> + if (lock->lock_pending) {
> /* remove pending lock requests completely */
> BUG_ON(i != DLM_BLOCKED_LIST);
> mlog(0, "node died with lock pending "
>
_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
https://oss.oracle.com/mailman/listinfo/ocfs2-devel
