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: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
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 @@
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 @@
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