The patch titled
Subject: ocfs2/dlm: return DLM_CANCELGRANT if the lock is on granted list and the operation is canceled
has been added to the -mm tree. Its filename is
ocfs2-dlm-return-dlm_cancelgrant-if-the-lock-is-on-granted-list-and-the-operation-is-canceled.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/ocfs2-dlm-return-dlm_cancelgrant-if-the-lock-is-on-granted-list-and-the-operation-is-canceled.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/ocfs2-dlm-return-dlm_cancelgrant-if-the-lock-is-on-granted-list-and-the-operation-is-canceled.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: wangjian <wangjian161@xxxxxxxxxx>
Subject: ocfs2/dlm: return DLM_CANCELGRANT if the lock is on granted list and the operation is canceled
In dlm_move_lockres_to_recovery_list(), if the lock is in the granted
queue and cancel_pending is set, it will encounter a BUG. I think this is
a meaningless BUG, so be prepared to remove it. A scenario that causes
this BUG will be given below.
At the beginning, Node 1 is the master and has NL lock, Node 2 has PR
lock, Node 3 has PR lock too.
Node 1 Node 2 Node 3
want to get EX lock.
want to get EX lock.
Node 3 hinder
Node 2 to get
EX lock, send
Node 3 a BAST.
receive BAST from
Node 1. downconvert
thread begin to
cancel PR to EX conversion.
In dlmunlock_common function,
downconvert thread has set
lock->cancel_pending,
but did not enter
dlm_send_remote_unlock_request
function.
Node2 dies because
the host is powered down.
In recovery process,
clean the lock that
related to Node2.
then finish Node 3
PR to EX request.
give Node 3 a AST.
receive AST from Node 1.
change lock level to EX,
move lock to granted list.
Node1 dies because
the host is powered down.
In dlm_move_lockres_to_recovery_list
function. the lock is in the
granted queue and cancel_pending
is set. BUG_ON.
But after clearing this BUG, process will encounter
the second BUG in the ocfs2_unlock_ast function.
Here is a scenario that will cause the second BUG
in ocfs2_unlock_ast as follows:
At the beginning, Node 1 is the master and has NL lock,
Node 2 has PR lock, Node 3 has PR lock too.
Node 1 Node 2 Node 3
want to get EX lock.
want to get EX lock.
Node 3 hinder
Node 2 to get
EX lock, send
Node 3 a BAST.
receive BAST from
Node 1. downconvert
thread begin to
cancel PR to EX conversion.
In dlmunlock_common function,
downconvert thread has released
lock->spinlock and res->spinlock,
but did not enter
dlm_send_remote_unlock_request
function.
Node2 dies because
the host is powered down.
In recovery process,
clean the lock that
related to Node2.
then finish Node 3
PR to EX request.
give Node 3 a AST.
receive AST from Node 1.
change lock level to EX,
move lock to granted list,
set lockres->l_unlock_action
as OCFS2_UNLOCK_INVALID
in ocfs2_locking_ast function.
Node2 dies because
the host is powered down.
Node 3 realize that Node 1
is dead, remove Node 1 from
domain_map. downconvert thread
get DLM_NORMAL from
dlm_send_remote_unlock_request
function and set *call_ast as 1.
Then downconvert thread meet
BUG in ocfs2_unlock_ast function.
To avoid meet the second BUG, dlmunlock_common() should return
DLM_CANCELGRANT if the lock is on granted list and the operation is
canceled.
Link: http://lkml.kernel.org/r/98f0e80c-9c13-dbb6-047c-b40e100082b1@xxxxxxxxxx
Signed-off-by: Jian Wang <wangjian161@xxxxxxxxxx>
Reviewed-by: Yiwen Jiang <jiangyiwen@xxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Joseph Qi <jiangqi903@xxxxxxxxx>
Cc: Changwei Ge <ge.changwei@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/dlm/dlmrecovery.c | 1 -
fs/ocfs2/dlm/dlmunlock.c | 5 +++++
2 files changed, 5 insertions(+), 1 deletion(-)
--- a/fs/ocfs2/dlm/dlmrecovery.c~ocfs2-dlm-return-dlm_cancelgrant-if-the-lock-is-on-granted-list-and-the-operation-is-canceled
+++ a/fs/ocfs2/dlm/dlmrecovery.c
@@ -2134,7 +2134,6 @@ void dlm_move_lockres_to_recovery_list(s
* if this had completed successfully
* before sending this lock state to the
* new master */
- BUG_ON(i != DLM_CONVERTING_LIST);
mlog(0, "node died with cancel pending "
"on %.*s. move back to granted list.\n",
res->lockname.len, res->lockname.name);
--- a/fs/ocfs2/dlm/dlmunlock.c~ocfs2-dlm-return-dlm_cancelgrant-if-the-lock-is-on-granted-list-and-the-operation-is-canceled
+++ a/fs/ocfs2/dlm/dlmunlock.c
@@ -183,6 +183,11 @@ static enum dlm_status dlmunlock_common(
flags, owner);
spin_lock(&res->spinlock);
spin_lock(&lock->spinlock);
+
+ if ((flags & LKM_CANCEL) &&
+ dlm_lock_on_list(&res->granted, lock))
+ status = DLM_CANCELGRANT;
+
/* if the master told us the lock was already granted,
* let the ast handle all of these actions */
if (status == DLM_CANCELGRANT) {
_
Patches currently in -mm which might be from wangjian161@xxxxxxxxxx are
ocfs2-dlm-clean-dlm_lksb_get_lvb-and-dlm_lksb_put_lvb-when-the-cancel_pending-is-set.patch
ocfs2-dlm-return-dlm_cancelgrant-if-the-lock-is-on-granted-list-and-the-operation-is-canceled.patch
