piaojun
2016-Jul-10 10:03 UTC
[Ocfs2-devel] 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...")
Signed-off-by: Jun Piao <piaojun at huawei.com>
---
fs/ocfs2/dlm/dlmmaster.c | 9 ++++++---
fs/ocfs2/dlm/dlmthread.c | 13 +++++++++++--
2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index f72e7ae..8c84641 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -2276,9 +2276,12 @@ int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct
dlm_lock_resource *res)
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 --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
index 68d239b..ce39722 100644
--- a/fs/ocfs2/dlm/dlmthread.c
+++ b/fs/ocfs2/dlm/dlmthread.c
@@ -175,6 +175,15 @@ static void dlm_purge_lockres(struct dlm_ctxt *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_ctxt *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;
--
1.8.4.3
Joseph Qi
2016-Jul-11 02:07 UTC
[Ocfs2-devel] ocfs2/dlm: solve a BUG when deref failed in dlm_drop_lockres_ref
On 2016/7/10 18:03, piaojun wrote:> 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...") > Signed-off-by: Jun Piao <piaojun at huawei.com>Use full patch title please. Others looks well. Thanks, Joseph> --- > fs/ocfs2/dlm/dlmmaster.c | 9 ++++++--- > fs/ocfs2/dlm/dlmthread.c | 13 +++++++++++-- > 2 files changed, 17 insertions(+), 5 deletions(-) > > diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c > index f72e7ae..8c84641 100644 > --- a/fs/ocfs2/dlm/dlmmaster.c > +++ b/fs/ocfs2/dlm/dlmmaster.c > @@ -2276,9 +2276,12 @@ int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) > 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 --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c > index 68d239b..ce39722 100644 > --- a/fs/ocfs2/dlm/dlmthread.c > +++ b/fs/ocfs2/dlm/dlmthread.c > @@ -175,6 +175,15 @@ static void dlm_purge_lockres(struct dlm_ctxt *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_ctxt *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; >