dm: process requeue in dm_wq_work

If barrier request was returned with DM_ENDIO_REQUEUE,
requeue it in dm_wq_work instead of dec_pending.

This allows us to correctly handle a situation when some targets
are asking for a requeue and other targets signal an error.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e34d694ddd04..910bce85f443 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -536,9 +536,11 @@ static void dec_pending(struct dm_io *io, int error)
                          * Target requested pushing back the I/O.
                          */
                         spin_lock_irqsave(&md->deferred_lock, flags);
-                        if (__noflush_suspending(md))
-                                bio_list_add_head(&md->deferred, io->bio);
-                        else
+                        if (__noflush_suspending(md)) {
+                                if (!bio_barrier(io->bio))
+                                        bio_list_add_head(&md->deferred,
+                                                          io->bio);
+                        } else
                                 /* noflush suspend was interrupted. */
                                 io->error = -EIO;
                         spin_unlock_irqrestore(&md->deferred_lock, flags);
@@ -1458,6 +1460,11 @@ static void process_barrier(struct mapped_device *md, struct bio *bio)
 
         if (md->barrier_error != DM_ENDIO_REQUEUE)
                 bio_endio(bio, md->barrier_error);
+        else {
+                spin_lock_irq(&md->deferred_lock);
+                bio_list_add_head(&md->deferred, bio);
+                spin_unlock_irq(&md->deferred_lock);
+        }
 }
 
 /*