From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm at linux-foundation.org Date: Thu, 28 Jul 2016 14:06:05 -0700 Subject: [Ocfs2-devel] [patch 4/5] ocfs2/dlm: solve a BUG when deref failed in dlm_drop_lockres_ref Message-ID: <579a73bd.aWzQ0Rkjfu9OwqME%akpm@linux-foundation.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com From: piaojun Subject: ocfs2/dlm: solve a BUG when deref failed in dlm_drop_lockres_ref We found a BUG situation that lockres is migrated during deref described below. To solve the BUG, we could purge lockres directly when other node says I did not have a ref. Additionally, we'd better purge lockres if master goes down, as no one will response deref done. Node 1 Node 2(old master) Node3(new master) dlm_purge_lockres send deref to N2 leave domain migrate lockres to N3 finish migration send do assert master to N1 receive do assert msg form N3, but can not find lockres because DROPPING_REF is set, so the owner is still N2. receive deref from N1 and response -EINVAL because lockres is migrated BUG when receive -EINVAL in dlm_drop_lockres_ref Fixes: 842b90b62461d ("ocfs2/dlm: return in progress if master can not clear the refmap bit right now") Link: http://lkml.kernel.org/r/57845103.3070406 at huawei.com Signed-off-by: Jun Piao Reviewed-by: Joseph Qi Reviewed-by: Jiufei Xue Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Signed-off-by: Andrew Morton --- fs/ocfs2/dlm/dlmmaster.c | 9 ++++++--- fs/ocfs2/dlm/dlmthread.c | 13 +++++++++++-- 2 files changed, 17 insertions(+), 5 deletions(-) diff -puN fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-solve-a-bug-when-deref-failed-in-dlm_drop_lockres_ref fs/ocfs2/dlm/dlmmaster.c --- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-solve-a-bug-when-deref-failed-in-dlm_drop_lockres_ref +++ a/fs/ocfs2/dlm/dlmmaster.c @@ -2276,9 +2276,12 @@ int dlm_drop_lockres_ref(struct dlm_ctxt mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n", dlm->name, namelen, lockname, res->owner, r); dlm_print_one_lock_resource(res); - BUG(); - } - return ret ? ret : r; + if (r == -ENOMEM) + BUG(); + } else + ret = r; + + return ret; } int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data, diff -puN fs/ocfs2/dlm/dlmthread.c~ocfs2-dlm-solve-a-bug-when-deref-failed-in-dlm_drop_lockres_ref fs/ocfs2/dlm/dlmthread.c --- a/fs/ocfs2/dlm/dlmthread.c~ocfs2-dlm-solve-a-bug-when-deref-failed-in-dlm_drop_lockres_ref +++ a/fs/ocfs2/dlm/dlmthread.c @@ -175,6 +175,15 @@ static void dlm_purge_lockres(struct dlm res->lockname.len, res->lockname.name, master); if (!master) { + if (res->state & DLM_LOCK_RES_DROPPING_REF) { + mlog(ML_NOTICE, "%s: res %.*s already in " + "DLM_LOCK_RES_DROPPING_REF state\n", + dlm->name, res->lockname.len, + res->lockname.name); + spin_unlock(&res->spinlock); + return; + } + res->state |= DLM_LOCK_RES_DROPPING_REF; /* drop spinlock... retake below */ spin_unlock(&res->spinlock); @@ -203,8 +212,8 @@ static void dlm_purge_lockres(struct dlm dlm->purge_count--; } - if (!master && ret != 0) { - mlog(0, "%s: deref %.*s in progress or master goes down\n", + if (!master && ret == DLM_DEREF_RESPONSE_INPROG) { + mlog(0, "%s: deref %.*s in progress\n", dlm->name, res->lockname.len, res->lockname.name); spin_unlock(&res->spinlock); return; _