dm mpath: hold io until all pg_inits completed

m->queue_io is set to block processing I/Os, and it needs to be kept
while pg-init, which issues multiple path activations, is in progress.
But m->queue is cleared when a path activation completes without error
in pg_init_done(), even while other path activations are in progress.
That may cause undesired -EIO on paths which are not complete activation.

This patch fixes that by not clearing m->queue_io until all path
activations complete.

(Before the hardware handlers were moved into the SCSI layer, pg_init
only used one path.)

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 11 insertions, 6 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 8fa0c955eeb5..ae187e5d7d58 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1181,14 +1181,19 @@ static void pg_init_done(void *data, int errors)
                         m->current_pgpath = NULL;
                         m->current_pg = NULL;
                 }
-        } else if (!m->pg_init_required) {
-                m->queue_io = 0;
+        } else if (!m->pg_init_required)
                 pg->bypassed = 0;
-        }
 
-        m->pg_init_in_progress--;
-        if (!m->pg_init_in_progress)
-                queue_work(kmultipathd, &m->process_queued_ios);
+        if (--m->pg_init_in_progress)
+                /* Activations of other paths are still on going */
+                goto out;
+
+        if (!m->pg_init_required)
+                m->queue_io = 0;
+
+        queue_work(kmultipathd, &m->process_queued_ios);
+
+out:
         spin_unlock_irqrestore(&m->lock, flags);
 }