[Ocfs2-devel] [patch 7/8] ocfs2: do not return DLM_MIGRATE_RESPONSE_MASTERY_REF to avoid endless, loop during umount
jiangyiwen
jiangyiwen at huawei.com
Fri Jun 13 02:21:04 PDT 2014
Mark:
Please help me to review following patch, Thank you very much!
----jiangyiwen
On 2014/6/10 4:04, akpm at linux-foundation.org wrote:
> From: jiangyiwen <jiangyiwen at huawei.com>
> Subject: ocfs2: do not return DLM_MIGRATE_RESPONSE_MASTERY_REF to avoid endless,loop during umount
>
> The following case may lead to endless loop during umount.
>
> node A node B node C node D
> umount volume,
> migrate lockres1
> to B
> want to lock lockres1,
> send
> MASTER_REQUEST_MSG
> to C
> init block mle
> send
> MIGRATE_REQUEST_MSG
> to C
> find a block
> mle, and then
> return
> DLM_MIGRATE_RESPONSE_MASTERY_REF
> to B
> set C in refmap
> umount successfully
> try to umount, endless
> loop occurs when migrate
> lockres1 since C is in
> refmap
>
> So we can fix this endless loop case by only returning
> DLM_MIGRATE_RESPONSE_MASTERY_REF if it has a mastery mle when receiving
> MIGRATE_REQUEST_MSG.
>
> [akpm at linux-foundation.org: coding-style fixes]
> Signed-off-by: jiangyiwen <jiangyiwen at huawei.com>
> Cc: Mark Fasheh <mfasheh at suse.com>
> Cc: Joel Becker <jlbec at evilplan.org>
> Cc: Xue jiufei <xuejiufei at huawei.com>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> ---
>
> fs/ocfs2/dlm/dlmmaster.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff -puN fs/ocfs2/dlm/dlmmaster.c~ocfs2-do-not-return-dlm_migrate_response_mastery_ref-to-avoid-endlessloop-during-umount fs/ocfs2/dlm/dlmmaster.c
> --- a/fs/ocfs2/dlm/dlmmaster.c~ocfs2-do-not-return-dlm_migrate_response_mastery_ref-to-avoid-endlessloop-during-umount
> +++ a/fs/ocfs2/dlm/dlmmaster.c
> @@ -3088,11 +3088,15 @@ static int dlm_add_migration_mle(struct
> /* remove it so that only one mle will be found */
> __dlm_unlink_mle(dlm, tmp);
> __dlm_mle_detach_hb_events(dlm, tmp);
> - ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
> - mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
> - "telling master to get ref for cleared out mle "
> - "during migration\n", dlm->name, namelen, name,
> - master, new_master);
> + if (tmp->type == DLM_MLE_MASTER) {
> + ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
> + mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
> + "telling master to get ref "
> + "for cleared out mle during "
> + "migration\n", dlm->name,
> + namelen, name, master,
> + new_master);
> + }
> }
> spin_unlock(&tmp->spinlock);
> }
> _
>
> .
>
More information about the Ocfs2-devel
mailing list