[Ocfs2-devel] [PATCH] ocfs2/dlm: remove BUG_ON in a rare case
Sunil Mushran
sunil.mushran at oracle.com
Wed Jul 14 18:37:57 PDT 2010
Signed-off-by: Sunil Mushran<sunil.mushran at oracle.com>
On 07/14/2010 07:38 AM, Wengang Wang wrote:
> For migration, we are waiting for DLM_LOCK_RES_MIGRATING flag to be set
> before sending DLM_MIG_LOCKRES_MSG message to the target. We are using
> dlm_migration_can_proceed() for that purpose. while, dlm_migration_can_proceed()
> also returns "go ahead" if target node is down. In this rare case, the
> DLM_LOCK_RES_MIGRATING maybe is not set yet. Remove the BUG_ON() in this case.
>
> Signed-off-by: Wengang Wang<wen.gang.wang at oracle.com>
> ---
> fs/ocfs2/dlm/dlmmaster.c | 22 ++++++++++++++--------
> 1 files changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
> index 4a7506a..94b97fc 100644
> --- a/fs/ocfs2/dlm/dlmmaster.c
> +++ b/fs/ocfs2/dlm/dlmmaster.c
> @@ -2808,14 +2808,8 @@ again:
> mlog(0, "trying again...\n");
> goto again;
> }
> - /* now that we are sure the MIGRATING state is there, drop
> - * the unneded state which blocked threads trying to DIRTY */
> - spin_lock(&res->spinlock);
> - BUG_ON(!(res->state& DLM_LOCK_RES_BLOCK_DIRTY));
> - BUG_ON(!(res->state& DLM_LOCK_RES_MIGRATING));
> - res->state&= ~DLM_LOCK_RES_BLOCK_DIRTY;
> - spin_unlock(&res->spinlock);
>
> + ret = 0;
> /* did the target go down or die? */
> spin_lock(&dlm->spinlock);
> if (!test_bit(target, dlm->domain_map)) {
> @@ -2826,9 +2820,21 @@ again:
> spin_unlock(&dlm->spinlock);
>
> /*
> + * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
> + * another try; otherwise, we are sure the MIGRATING state is there,
> + * drop the unneded state which blocked threads trying to DIRTY
> + */
> + spin_lock(&res->spinlock);
> + BUG_ON(!(res->state& DLM_LOCK_RES_BLOCK_DIRTY));
> + res->state&= ~DLM_LOCK_RES_BLOCK_DIRTY;
> + if (!ret)
> + BUG_ON(!(res->state& DLM_LOCK_RES_MIGRATING));
> + spin_unlock(&res->spinlock);
> +
> + /*
> * at this point:
> *
> - * o the DLM_LOCK_RES_MIGRATING flag is set
> + * o the DLM_LOCK_RES_MIGRATING flag is set if target not down
> * o there are no pending asts on this lockres
> * o all processes trying to reserve an ast on this
> * lockres must wait for the MIGRATING flag to clear
>
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