dm thin: suspend/resume active thin devices when reloading thin-pool

Before this change it was expected that userspace would first suspend
all active thin devices, reload/resize the thin-pool target, then resume
all active thin devices.  Now the thin-pool suspend/resume will trigger
the suspend/resume of all active thins via appropriate calls to
dm_internal_suspend and dm_internal_resume.

Store the mapped_device for each thin device in struct thin_c to make
these calls possible.

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

1 files changed, 38 insertions, 2 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index f1b53e31d868..e9e9584fe769 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -292,6 +292,8 @@ struct thin_c {
 
         struct pool *pool;
         struct dm_thin_device *td;
+        struct mapped_device *thin_md;
+
         bool requeue_mode:1;
         spinlock_t lock;
         struct list_head deferred_cells;
@@ -3113,19 +3115,48 @@ static int pool_preresume(struct dm_target *ti)
         return 0;
 }
 
+static void pool_suspend_active_thins(struct pool *pool)
+{
+        struct thin_c *tc;
+
+        /* Suspend all active thin devices */
+        tc = get_first_thin(pool);
+        while (tc) {
+                dm_internal_suspend_noflush(tc->thin_md);
+                tc = get_next_thin(pool, tc);
+        }
+}
+
+static void pool_resume_active_thins(struct pool *pool)
+{
+        struct thin_c *tc;
+
+        /* Resume all active thin devices */
+        tc = get_first_thin(pool);
+        while (tc) {
+                dm_internal_resume(tc->thin_md);
+                tc = get_next_thin(pool, tc);
+        }
+}
+
 static void pool_resume(struct dm_target *ti)
 {
         struct pool_c *pt = ti->private;
         struct pool *pool = pt->pool;
         unsigned long flags;
 
+        /*
+         * Must requeue active_thins' bios and then resume
+         * active_thins _before_ clearing 'suspend' flag.
+         */
+        requeue_bios(pool);
+        pool_resume_active_thins(pool);
+
         spin_lock_irqsave(&pool->lock, flags);
         pool->low_water_triggered = false;
         pool->suspended = false;
         spin_unlock_irqrestore(&pool->lock, flags);
 
-        requeue_bios(pool);
-
         do_waker(&pool->waker.work);
 }
 
@@ -3138,6 +3169,8 @@ static void pool_presuspend(struct dm_target *ti)
         spin_lock_irqsave(&pool->lock, flags);
         pool->suspended = true;
         spin_unlock_irqrestore(&pool->lock, flags);
+
+        pool_suspend_active_thins(pool);
 }
 
 static void pool_presuspend_undo(struct dm_target *ti)
@@ -3146,6 +3179,8 @@ static void pool_presuspend_undo(struct dm_target *ti)
         struct pool *pool = pt->pool;
         unsigned long flags;
 
+        pool_resume_active_thins(pool);
+
         spin_lock_irqsave(&pool->lock, flags);
         pool->suspended = false;
         spin_unlock_irqrestore(&pool->lock, flags);
@@ -3703,6 +3738,7 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
                 r = -ENOMEM;
                 goto out_unlock;
         }
+        tc->thin_md = dm_table_get_md(ti->table);
         spin_lock_init(&tc->lock);
         INIT_LIST_HEAD(&tc->deferred_cells);
         bio_list_init(&tc->deferred_bio_list);