From: akpm at linux-foundation.org <akpm@linux-foundation.org>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] [patch 5/8] ocfs2: do not return DLM_MIGRATE_RESPONSE_MASTERY_REF to avoid endless, loop during umount
Date: Wed, 19 Mar 2014 14:10:03 -0700 [thread overview]
Message-ID: <20140319211004.23C7F31C1E1@corp2gmr1-1.hot.corp.google.com> (raw)
From: jiangyiwen <jiangyiwen@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@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Xue jiufei <xuejiufei@huawei.com>
Signed-off-by: Andrew Morton <akpm@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
@@ -3084,11 +3084,15 @@ 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);
}
_
next reply other threads:[~2014-03-19 21:10 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-19 21:10 akpm at linux-foundation.org [this message]
2014-03-31 2:23 ` [Ocfs2-devel] [patch 5/8] ocfs2: do not return DLM_MIGRATE_RESPONSE_MASTERY_REF to avoid endless, loop during umount Mark Fasheh
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