akpm at linux-foundation.org
2016-Jul-28 21:06 UTC
[Ocfs2-devel] [patch 5/5] ocfs2/dlm: continue to purge recovery lockres when recovery master goes down
From: piaojun <piaojun at huawei.com>
Subject: ocfs2/dlm: continue to purge recovery lockres when recovery master goes
down
We found a dlm-blocked situation caused by continuous breakdown of
recovery masters described below. To solve this problem, we should purge
recovery lock once detecting recovery master goes down.
N3 N2 N1(reco master)
go down
pick up recovery lock and
begin recoverying for N2
go down
pick up recovery
lock failed, then
purge it:
dlm_purge_lockres
->DROPPING_REF is set
send deref to N1 failed,
recovery lock is not purged
find N1 go down, begin
recoverying for N1, but
blocked in dlm_do_recovery
as DROPPING_REF is set:
dlm_do_recovery
->dlm_pick_recovery_master
->dlmlock
->dlm_get_lock_resource
->__dlm_wait_on_lockres_flags(tmpres,
DLM_LOCK_RES_DROPPING_REF);
Fixes: 8c0343968163 ("ocfs2/dlm: clear DROPPING_REF flag when the master
goes down")
Link: http://lkml.kernel.org/r/578453AF.8030404 at huawei.com
Signed-off-by: Jun Piao <piaojun at huawei.com>
Reviewed-by: Joseph Qi <joseph.qi at huawei.com>
Reviewed-by: Jiufei Xue <xuejiufei at huawei.com>
Cc: Mark Fasheh <mfasheh at suse.de>
Cc: Joel Becker <jlbec at evilplan.org>
Cc: Junxiao Bi <junxiao.bi at oracle.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
---
fs/ocfs2/dlm/dlmcommon.h | 2 +
fs/ocfs2/dlm/dlmmaster.c | 37 ++----------------------
fs/ocfs2/dlm/dlmrecovery.c | 29 ++++++++++++++-----
fs/ocfs2/dlm/dlmthread.c | 52 ++++++++++++++++++++++++++++++++---
4 files changed, 74 insertions(+), 46 deletions(-)
diff -puN
fs/ocfs2/dlm/dlmcommon.h~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
fs/ocfs2/dlm/dlmcommon.h
---
a/fs/ocfs2/dlm/dlmcommon.h~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
+++ a/fs/ocfs2/dlm/dlmcommon.h
@@ -1004,6 +1004,8 @@ int dlm_finalize_reco_handler(struct o2n
int dlm_do_master_requery(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
u8 nodenum, u8 *real_master);
+void __dlm_do_purge_lockres(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res);
int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res,
diff -puN
fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
fs/ocfs2/dlm/dlmmaster.c
---
a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
+++ a/fs/ocfs2/dlm/dlmmaster.c
@@ -2425,51 +2425,20 @@ int dlm_deref_lockres_done_handler(struc
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);
- list_del_init(&res->purge);
- dlm_lockres_put(res);
- dlm->purge_count--;
- }
-
- if (!__dlm_lockres_unused(res)) {
- mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
- dlm->name, res->lockname.len, res->lockname.name);
- __dlm_print_one_lock_resource(res);
- BUG();
- }
-
- __dlm_unhash_lockres(dlm, res);
-
- spin_lock(&dlm->track_lock);
- if (!list_empty(&res->tracking))
- list_del_init(&res->tracking);
- else {
- mlog(ML_ERROR, "%s: Resource %.*s not on the Tracking list\n",
- dlm->name, res->lockname.len, res->lockname.name);
- __dlm_print_one_lock_resource(res);
- }
- spin_unlock(&dlm->track_lock);
-
- /* lockres is not in the hash now. drop the flag and wake up
- * any processes waiting in dlm_get_lock_resource.
- */
- res->state &= ~DLM_LOCK_RES_DROPPING_REF;
+ __dlm_do_purge_lockres(dlm, res);
spin_unlock(&res->spinlock);
wake_up(&res->wq);
- dlm_lockres_put(res);
-
spin_unlock(&dlm->spinlock);
ret = 0;
done:
+ if (res)
+ dlm_lockres_put(res);
dlm_put(dlm);
return ret;
}
diff -puN
fs/ocfs2/dlm/dlmrecovery.c~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
fs/ocfs2/dlm/dlmrecovery.c
---
a/fs/ocfs2/dlm/dlmrecovery.c~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
+++ a/fs/ocfs2/dlm/dlmrecovery.c
@@ -2343,6 +2343,7 @@ static void dlm_do_local_recovery_cleanu
struct dlm_lock_resource *res;
int i;
struct hlist_head *bucket;
+ struct hlist_node *tmp;
struct dlm_lock *lock;
@@ -2365,7 +2366,7 @@ static void dlm_do_local_recovery_cleanu
*/
for (i = 0; i < DLM_HASH_BUCKETS; i++) {
bucket = dlm_lockres_hash(dlm, i);
- hlist_for_each_entry(res, bucket, hash_node) {
+ hlist_for_each_entry_safe(res, tmp, bucket, hash_node) {
/* always prune any $RECOVERY entries for dead nodes,
* otherwise hangs can occur during later recovery */
if (dlm_is_recovery_lock(res->lockname.name,
@@ -2386,8 +2387,17 @@ static void dlm_do_local_recovery_cleanu
break;
}
}
- dlm_lockres_clear_refmap_bit(dlm, res,
- dead_node);
+
+ if ((res->owner == dead_node) &&
+ (res->state & DLM_LOCK_RES_DROPPING_REF)) {
+ dlm_lockres_get(res);
+ __dlm_do_purge_lockres(dlm, res);
+ spin_unlock(&res->spinlock);
+ wake_up(&res->wq);
+ dlm_lockres_put(res);
+ continue;
+ } else if (res->owner == dlm->node_num)
+ dlm_lockres_clear_refmap_bit(dlm, res, dead_node);
spin_unlock(&res->spinlock);
continue;
}
@@ -2398,14 +2408,17 @@ static void dlm_do_local_recovery_cleanu
if (res->state & DLM_LOCK_RES_DROPPING_REF) {
mlog(0, "%s:%.*s: owned by "
"dead node %u, this node was "
- "dropping its ref when it died. "
- "continue, dropping the flag.\n",
+ "dropping its ref when master died. "
+ "continue, purging the lockres.\n",
dlm->name, res->lockname.len,
res->lockname.name, dead_node);
+ dlm_lockres_get(res);
+ __dlm_do_purge_lockres(dlm, res);
+ spin_unlock(&res->spinlock);
+ wake_up(&res->wq);
+ dlm_lockres_put(res);
+ continue;
}
- res->state &= ~DLM_LOCK_RES_DROPPING_REF;
- dlm_move_lockres_to_recovery_list(dlm,
- res);
} else if (res->owner == dlm->node_num) {
dlm_free_dead_locks(dlm, res, dead_node);
__dlm_lockres_calc_usage(dlm, res);
diff -puN
fs/ocfs2/dlm/dlmthread.c~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
fs/ocfs2/dlm/dlmthread.c
---
a/fs/ocfs2/dlm/dlmthread.c~ocfs2-dlm-continue-to-purge-recovery-lockres-when-recovery-master-goes-down
+++ a/fs/ocfs2/dlm/dlmthread.c
@@ -160,6 +160,52 @@ void dlm_lockres_calc_usage(struct dlm_c
spin_unlock(&dlm->spinlock);
}
+/*
+ * Do the real purge work:
+ * unhash the lockres, and
+ * clear flag DLM_LOCK_RES_DROPPING_REF.
+ * It requires dlm and lockres spinlock to be taken.
+ */
+void __dlm_do_purge_lockres(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res)
+{
+ assert_spin_locked(&dlm->spinlock);
+ assert_spin_locked(&res->spinlock);
+
+ if (!list_empty(&res->purge)) {
+ mlog(0, "%s: Removing res %.*s from purgelist\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ list_del_init(&res->purge);
+ dlm_lockres_put(res);
+ dlm->purge_count--;
+ }
+
+ if (!__dlm_lockres_unused(res)) {
+ mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ __dlm_print_one_lock_resource(res);
+ BUG();
+ }
+
+ __dlm_unhash_lockres(dlm, res);
+
+ spin_lock(&dlm->track_lock);
+ if (!list_empty(&res->tracking))
+ list_del_init(&res->tracking);
+ else {
+ mlog(ML_ERROR, "%s: Resource %.*s not on the Tracking list\n",
+ dlm->name, res->lockname.len, res->lockname.name);
+ __dlm_print_one_lock_resource(res);
+ }
+ spin_unlock(&dlm->track_lock);
+
+ /*
+ * lockres is not in the hash now. drop the flag and wake up
+ * any processes waiting in dlm_get_lock_resource.
+ */
+ res->state &= ~DLM_LOCK_RES_DROPPING_REF;
+}
+
static void dlm_purge_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
@@ -176,10 +222,8 @@ static void dlm_purge_lockres(struct dlm
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);
+ 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;
}
_
Mark Fasheh
2016-Jul-28 22:23 UTC
[Ocfs2-devel] [patch 5/5] ocfs2/dlm: continue to purge recovery lockres when recovery master goes down
On Thu, Jul 28, 2016 at 02:06:08PM -0700, Andrew Morton wrote:> From: piaojun <piaojun at huawei.com> > Subject: ocfs2/dlm: continue to purge recovery lockres when recovery master goes down > > We found a dlm-blocked situation caused by continuous breakdown of > recovery masters described below. To solve this problem, we should purge > recovery lock once detecting recovery master goes down. > > N3 N2 N1(reco master) > go down > pick up recovery lock and > begin recoverying for N2 > > go down > > pick up recovery > lock failed, then > purge it: > dlm_purge_lockres > ->DROPPING_REF is set > > send deref to N1 failed, > recovery lock is not purged > > find N1 go down, begin > recoverying for N1, but > blocked in dlm_do_recovery > as DROPPING_REF is set: > dlm_do_recovery > ->dlm_pick_recovery_master > ->dlmlock > ->dlm_get_lock_resource > ->__dlm_wait_on_lockres_flags(tmpres, > DLM_LOCK_RES_DROPPING_REF); > > Fixes: 8c0343968163 ("ocfs2/dlm: clear DROPPING_REF flag when the master goes down") > Link: http://lkml.kernel.org/r/578453AF.8030404 at huawei.com > Signed-off-by: Jun Piao <piaojun at huawei.com> > Reviewed-by: Joseph Qi <joseph.qi at huawei.com> > Reviewed-by: Jiufei Xue <xuejiufei at huawei.com>Reviewed-by: Mark Fasheh <mfasheh at suse.de> --Mark -- Mark Fasheh