Commit b9aaac5a authored Jun 23, 2014 by jiangyiwen Committed by Linus Torvalds Jun 23, 2014

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@linux-foundation.org: coding-style fixes]
Signed-off-by: jiangyiwen <jiangyiwen@huawei.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Xue jiufei <xuejiufei@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 595297a8

fs/ocfs2/dlm/dlmmaster.c

+9 −5

Original line number	Diff line number	Diff line
		@@ -3088,11 +3088,15 @@ static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
		/* remove it so that only one mle will be found */
		__dlm_unlink_mle(dlm, tmp);
		__dlm_mle_detach_hb_events(dlm, tmp);
		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);
		"telling master to get ref "
		"for cleared out mle during "
		"migration\n", dlm->name,
		namelen, name, master,
		new_master);
		}
		}
		spin_unlock(&tmp->spinlock);
		}

Admin message