From mboxrd@z Thu Jan 1 00:00:00 1970 From: piaojun Date: Fri, 15 Feb 2019 16:36:03 +0800 Subject: [Ocfs2-devel] [PATCH] ocfs2: wait for recovering done after direct unlock request In-Reply-To: <63ADC13FD55D6546B7DECE290D39E3730127854170@H3CMLB14-EX.srv.huawei-3com.com> References: <1550124866-20367-1-git-send-email-ge.changwei@h3c.com> <5C6659FA.2000100@huawei.com> <63ADC13FD55D6546B7DECE290D39E3730127854170@H3CMLB14-EX.srv.huawei-3com.com> Message-ID: <5C6679F3.3020306@huawei.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com Hi Changwei, Thanks for your explaination, and I still have a question below. On 2019/2/15 14:29, Changwei Ge wrote: > Hi Jun, > > On 2019/2/15 14:20, piaojun wrote: >> Hi Changwei, >> >> The DLM process is a little bit complex, so I suggest pasting the code >> path. And I wonder if my code is right? >> >> Thanks, >> Jun >> >> On 2019/2/14 14:14, Changwei Ge wrote: >>> There is scenario causing ocfs2 umount hang when multiple hosts are >>> rebooting at the same time. >>> >>> NODE1 NODE2 NODE3 >>> send unlock requset to NODE2 >>> dies >>> become recovery master >>> recover NODE2 >>> find NODE2 dead >>> mark resource RECOVERING >>> directly remove lock from grant list >> dlm_do_local_recovery_cleanup >> dlm_move_lockres_to_recovery_list >> res->state |= DLM_LOCK_RES_RECOVERING; >> list_add_tail(&res->recovering, &dlm->reco.resources); >> >>> calculate usage but RECOVERING marked >>> **miss the window of purging >> dlmunlock >> dlmunlock_remote >> dlmunlock_common // unlock successfully directly >> >> dlm_lockres_calc_usage >> __dlm_lockres_calc_usage >> __dlm_lockres_unused >> if (res->state & (DLM_LOCK_RES_RECOVERING| // won't purge lock as DLM_LOCK_RES_RECOVERING is set > > True. > >> >>> clear RECOVERING >> dlm_finish_local_lockres_recovery >> res->state &= ~DLM_LOCK_RES_RECOVERING; >> >> Could you help explaining where getting stuck? > > Sure, > As dlm missed the window to purge lock resource, it can't be unhashed. > > During umount: > dlm_unregister_domain > dlm_migrate_all_locks -> there is always a lock resource hashed, so can't return from dlm_migrate_all_locks() thus hang during umount. In dlm_migrate_all_locks, lockres will be move to purge_list and purged again: dlm_migrate_all_locks __dlm_lockres_calc_usage list_add_tail(&res->purge, &dlm->purge_list); Do you mean this process does not work? > > Thanks, > Changwei > > >> >>> >>> To reproduce this iusse, crash a host and then umount ocfs2 >>> from another node. >>> >>> To sovle this, just let unlock progress wait for recovery done. >>> >>> Signed-off-by: Changwei Ge >>> --- >>> fs/ocfs2/dlm/dlmunlock.c | 23 +++++++++++++++++++---- >>> 1 file changed, 19 insertions(+), 4 deletions(-) >>> >>> diff --git a/fs/ocfs2/dlm/dlmunlock.c b/fs/ocfs2/dlm/dlmunlock.c >>> index 63d701c..c8e9b70 100644 >>> --- a/fs/ocfs2/dlm/dlmunlock.c >>> +++ b/fs/ocfs2/dlm/dlmunlock.c >>> @@ -105,7 +105,8 @@ static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm, >>> enum dlm_status status; >>> int actions = 0; >>> int in_use; >>> - u8 owner; >>> + u8 owner; >>> + int recovery_wait = 0; >>> >>> mlog(0, "master_node = %d, valblk = %d\n", master_node, >>> flags & LKM_VALBLK); >>> @@ -208,9 +209,12 @@ static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm, >>> } >>> if (flags & LKM_CANCEL) >>> lock->cancel_pending = 0; >>> - else >>> - lock->unlock_pending = 0; >>> - >>> + else { >>> + if (!lock->unlock_pending) >>> + recovery_wait = 1; >>> + else >>> + lock->unlock_pending = 0; >>> + } >>> } >>> >>> /* get an extra ref on lock. if we are just switching >>> @@ -244,6 +248,17 @@ static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm, >>> spin_unlock(&res->spinlock); >>> wake_up(&res->wq); >>> >>> + if (recovery_wait) { >>> + spin_lock(&res->spinlock); >>> + /* Unlock request will directly succeed after owner dies, >>> + * and the lock is already removed from grant list. We have to >>> + * wait for RECOVERING done or we miss the chance to purge it >>> + * since the removement is much faster than RECOVERING proc. >>> + */ >>> + __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_RECOVERING); >>> + spin_unlock(&res->spinlock); >>> + } >>> + >>> /* let the caller's final dlm_lock_put handle the actual kfree */ >>> if (actions & DLM_UNLOCK_FREE_LOCK) { >>> /* this should always be coupled with list removal */ >>> >> > . >