From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm at linux-foundation.org Date: Thu, 28 Jul 2016 14:06:08 -0700 Subject: [Ocfs2-devel] [patch 5/5] ocfs2/dlm: continue to purge recovery lockres when recovery master goes down Message-ID: <579a73c0.oJg/IWMTrvYSga3x%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: 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 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/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; } _