dm: add presuspend_undo hook to target_type

The DM thin-pool target now must undo the changes performed during
pool_presuspend() so introduce presuspend_undo hook in target_type.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f8cdd97c28a7..f84de3215982 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2756,7 +2756,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
         if (noflush)
                 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
 
-        /* This does not get reverted if there's an error later. */
+        /*
+         * This gets reverted if there's an error later and the targets
+         * provide the .presuspend_undo hook.
+         */
         dm_table_presuspend_targets(map);
 
         /*
@@ -2767,8 +2770,10 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
          */
         if (!noflush && do_lockfs) {
                 r = lock_fs(md);
-                if (r)
+                if (r) {
+                        dm_table_presuspend_undo_targets(map);
                         goto out_unlock;
+                }
         }
 
         /*
@@ -2816,6 +2821,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
                         start_queue(md->queue);
 
                 unlock_fs(md);
+                dm_table_presuspend_undo_targets(map);
                 goto out_unlock; /* pushback list is already flushed, so skip flush */
         }