Message ID | 579a73ba.w6r/vSvvhIAjJAxY%akpm@linux-foundation.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On Thu, Jul 28, 2016 at 02:06:02PM -0700, Andrew Morton wrote: > From: piaojun <piaojun@huawei.com> > Subject: ocfs2/dlm: disable BUG_ON when DLM_LOCK_RES_DROPPING_REF is cleared before dlm_deref_lockres_done_handler > > We found a BUG situation in which DLM_LOCK_RES_DROPPING_REF is cleared > unexpected that described below. To solve the bug, we disable the BUG_ON > and purge lockres in dlm_do_local_recovery_cleanup. > > Node 1 Node 2(master) > dlm_purge_lockres > dlm_deref_lockres_handler > > DLM_LOCK_RES_SETREF_INPROG is set > response DLM_DEREF_RESPONSE_INPROG > > receive DLM_DEREF_RESPONSE_INPROG > stop puring in dlm_purge_lockres > and wait for DLM_DEREF_RESPONSE_DONE > > dispatch dlm_deref_lockres_worker > response DLM_DEREF_RESPONSE_DONE > > receive DLM_DEREF_RESPONSE_DONE and > prepare to purge lockres > > Node 2 goes down > > find Node2 down and do local > clean up for Node2: > dlm_do_local_recovery_cleanup > -> clear DLM_LOCK_RES_DROPPING_REF > > when purging lockres, BUG_ON happens > because DLM_LOCK_RES_DROPPING_REF is clear: > dlm_deref_lockres_done_handler > ->BUG_ON(!(res->state & DLM_LOCK_RES_DROPPING_REF)); Thanks Piaojun, Reviewed-by: Mark Fasheh <mfasheh@suse.de> --Mark -- Mark Fasheh
diff -puN fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-disable-bug_on-when-dlm_lock_res_dropping_ref-is-cleared-before-dlm_deref_lockres_done_handler fs/ocfs2/dlm/dlmmaster.c --- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-disable-bug_on-when-dlm_lock_res_dropping_ref-is-cleared-before-dlm_deref_lockres_done_handler +++ a/fs/ocfs2/dlm/dlmmaster.c @@ -2416,7 +2416,17 @@ int dlm_deref_lockres_done_handler(struc } spin_lock(&res->spinlock); - BUG_ON(!(res->state & DLM_LOCK_RES_DROPPING_REF)); + if (!(res->state & DLM_LOCK_RES_DROPPING_REF)) { + spin_unlock(&res->spinlock); + spin_unlock(&dlm->spinlock); + mlog(ML_NOTICE, "%s:%.*s: node %u sends deref done " + "but it is already derefed!\n", dlm->name, + res->lockname.len, res->lockname.name, node); + dlm_lockres_put(res); + ret = 0; + goto done; + } + if (!list_empty(&res->purge)) { mlog(0, "%s: Removing res %.*s from purgelist\n", dlm->name, res->lockname.len, res->lockname.name); @@ -2456,7 +2466,6 @@ int dlm_deref_lockres_done_handler(struc spin_unlock(&dlm->spinlock); ret = 0; - done: dlm_put(dlm); return ret;