Subject: + ocfs2-dlmlock_master-should-return-dlm_normal-after-adding-lock-to-blocked-list.patch added to -mm tree
To: xuejiufei@xxxxxxxxxx,jeff.liu@xxxxxxxxxx,jlbec@xxxxxxxxxxxx,mfasheh@xxxxxxxx,shencanquan@xxxxxxxxxx,sunil.mushran@xxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 25 Jun 2013 16:39:58 -0700
The patch titled
Subject: ocfs2: dlmlock_master() should return DLM_NORMAL after adding lock to blocked list
has been added to the -mm tree. Its filename is
ocfs2-dlmlock_master-should-return-dlm_normal-after-adding-lock-to-blocked-list.patch
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From: Xue jiufei <xuejiufei@xxxxxxxxxx>
Subject: ocfs2: dlmlock_master() should return DLM_NORMAL after adding lock to blocked list
dlmlock_master() returns DLM_RECOVERING/DLM_MIGRATING/ DLM_FORWAR after
adding lock to blocked list if lockres has the state
DLM_LOCK_RES_RECOVERING/DLM_LOCK_RES_MIGRATING/ DLM_LOCK_RES_IN_PROGRESS.
so it will retry in dlmlock(). And this may cause dlm_thread fall into an
infinite loop
Thread1 dlm_thread
calls dlm_lock->dlmlock_master,
if lockresA is in state
DLM_LOCK_RES_RECOVERING, calls
__dlm_wait_on_lockres() and waits
until others threads clear this
state;
If cannot grant this lock,
adding lock to blocked list,
and return DLM_RECOVERING;
Grant this lock and move it to
grant list;
After a while, retry and
calls list_add_tail(), adding lock
to blocked list again.
Granted and blocked list of this lockres will become the following
conditions:
lock_res->granted.next = dlm_lock->list_head;
lock_res->blocked.next = dlm_lock->list_head;
dlm_lock->list_head.next = dlm_lock_resource->blocked;
When dlm_thread traverses the granted list, it will fall into an endless
loop, checking dlm_lock.list_head, dlm_lock->list_head.next
(i.e.lock_res->blocked), lock_res->blocked.next(i.e.dlm_lock.list_head
again) .....
Signed-off-by: joyce <xuejiufei@xxxxxxxxxx>
Reviewed-by: jensen <shencanquan@xxxxxxxxxx>
Cc: Jeff Liu <jeff.liu@xxxxxxxxxx>
Cc: Sunil Mushran <sunil.mushran@xxxxxxxxx>
Cc: Mark Fasheh <mfasheh@xxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/dlm/dlmlock.c | 1 +
1 file changed, 1 insertion(+)
diff -puN fs/ocfs2/dlm/dlmlock.c~ocfs2-dlmlock_master-should-return-dlm_normal-after-adding-lock-to-blocked-list fs/ocfs2/dlm/dlmlock.c
--- a/fs/ocfs2/dlm/dlmlock.c~ocfs2-dlmlock_master-should-return-dlm_normal-after-adding-lock-to-blocked-list
+++ a/fs/ocfs2/dlm/dlmlock.c
@@ -178,6 +178,7 @@ static enum dlm_status dlmlock_master(st
lock->ml.node);
}
} else {
+ status = DLM_NORMAL;
dlm_lock_get(lock);
list_add_tail(&lock->list, &res->blocked);
kick_thread = 1;
_
Patches currently in -mm which might be from xuejiufei@xxxxxxxxxx are
linux-next.patch
ocfs2-add-missing-dlm_put-in-dlm_begin_reco_handler.patch
ocfs2-dlmlock_master-should-return-dlm_normal-after-adding-lock-to-blocked-list.patch
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