[Ocfs2-devel] [patch 25/25] ocfs2/dlm: move lock to the tail of grant queue while doing in-place convert
Joseph Qi
joseph.qi at huawei.com
Wed Mar 23 17:21:04 PDT 2016
On 2016/3/24 4:12, akpm at linux-foundation.org wrote:
> From: xuejiufei <xuejiufei at huawei.com>
> Subject: ocfs2/dlm: move lock to the tail of grant queue while doing in-place convert
>
> We have found a bug when two nodes doing umount one after another.
>
> 1) Node 1 migrate a lockres that has 3 locks in grant queue such as
> N2(PR)<->N3(NL)<->N4(PR) to N2. After migration, lvb of the lock
> N3(NL) and N4(PR) are empty on node 2 because migration target do not
> copy lvb to these two lock.
>
> 2) Node 3 want to convert to PR, it can be granted in
> __dlmconvert_master(), and the order of these locks is unchanged. The
> lvb of the lock N3(PR) on node 2 is copyed from lockres in function
> dlm_update_lvb() while the lvb of lock N4(PR) is still empty.
>
> 3) Node 2 want to leave domain, it will migrate this lockres to node 3.
> Then node 2 will trigger the BUG in dlm_prepare_lvb_for_migration()
> when adding the lock N4(PR) to mres with the following message because
> the lvb of mres is already copied from lock N3(PR), but the lvb of lock
> N4(PR) is empty.
>
> "Mismatched lvb in lock cookie=%u:%llu, name=%.*s, node=%u"
>
> [akpm at linux-foundation.org: tweak comment]
> Signed-off-by: xuejiufei <xuejiufei at huawei.com>
Acked-by: Joseph Qi <joseph.qi 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>
> Cc: Joseph Qi <joseph.qi at huawei.com>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> ---
>
> fs/ocfs2/dlm/dlmconvert.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff -puN fs/ocfs2/dlm/dlmconvert.c~ocfs2-dlm-move-lock-to-the-tail-of-grant-queue-while-doing-in-place-convert fs/ocfs2/dlm/dlmconvert.c
> --- a/fs/ocfs2/dlm/dlmconvert.c~ocfs2-dlm-move-lock-to-the-tail-of-grant-queue-while-doing-in-place-convert
> +++ a/fs/ocfs2/dlm/dlmconvert.c
> @@ -212,6 +212,12 @@ grant:
> if (lock->lksb->flags & DLM_LKSB_PUT_LVB)
> memcpy(res->lvb, lock->lksb->lvb, DLM_LVB_LEN);
>
> + /*
> + * Move the lock to the tail because it may be the only lock which has
> + * an invalid lvb.
> + */
> + list_move_tail(&lock->list, &res->granted);
> +
> status = DLM_NORMAL;
> *call_ast = 1;
> goto unlock_exit;
> _
>
> .
>
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