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>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e34d694..910bce8 100644 (file)
--- 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);
+       }
 }
 
 /*