Commit a39953dd authored by Wengang Wang's avatar Wengang Wang Committed by Joel Becker
Browse files

ocfs2/dlm: Remove BUG_ON from migration in the rare case of a down node 



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.  However, if the node is
down, dlm_migration_can_proceed() will also return "go ahead".  In this
rare case, the DLM_LOCK_RES_MIGRATING flag might not be set yet. Remove
the BUG_ON() that trips over this condition.

Signed-off-by: default avatarWengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
parent f5e27b6d

fs/ocfs2/dlm/dlmmaster.c

+14 −8
Original line number Diff line number Diff line
@@ -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)) {
@@ -2825,10 +2819,22 @@ 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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