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>

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index b2bd1eb..3afae9e 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1521,18 +1521,32 @@ fmode_t dm_table_get_mode(struct dm_table *t)
 }
 EXPORT_SYMBOL(dm_table_get_mode);
 
-static void suspend_targets(struct dm_table *t, unsigned postsuspend)
+enum suspend_mode {
+       PRESUSPEND,
+       PRESUSPEND_UNDO,
+       POSTSUSPEND,
+};
+
+static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
 {
        int i = t->num_targets;
        struct dm_target *ti = t->targets;
 
        while (i--) {
-               if (postsuspend) {
+               switch (mode) {
+               case PRESUSPEND:
+                       if (ti->type->presuspend)
+                               ti->type->presuspend(ti);
+                       break;
+               case PRESUSPEND_UNDO:
+                       if (ti->type->presuspend_undo)
+                               ti->type->presuspend_undo(ti);
+                       break;
+               case POSTSUSPEND:
                        if (ti->type->postsuspend)
                                ti->type->postsuspend(ti);
-               } else if (ti->type->presuspend)
-                       ti->type->presuspend(ti);
-
+                       break;
+               }
                ti++;
        }
 }
@@ -1542,7 +1556,15 @@ void dm_table_presuspend_targets(struct dm_table *t)
        if (!t)
                return;
 
-       suspend_targets(t, 0);
+       suspend_targets(t, PRESUSPEND);
+}
+
+void dm_table_presuspend_undo_targets(struct dm_table *t)
+{
+       if (!t)
+               return;
+
+       suspend_targets(t, PRESUSPEND_UNDO);
 }
 
 void dm_table_postsuspend_targets(struct dm_table *t)
@@ -1550,7 +1572,7 @@ void dm_table_postsuspend_targets(struct dm_table *t)
        if (!t)
                return;
 
-       suspend_targets(t, 1);
+       suspend_targets(t, POSTSUSPEND);
 }
 
 int dm_table_resume_targets(struct dm_table *t)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index f8cdd97..f84de32 100644 (file)
--- 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 */
        }
 

diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 988c7fb..7819940 100644 (file)
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -65,6 +65,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
                               struct queue_limits *limits);
 struct list_head *dm_table_get_devices(struct dm_table *t);
 void dm_table_presuspend_targets(struct dm_table *t);
+void dm_table_presuspend_undo_targets(struct dm_table *t);
 void dm_table_postsuspend_targets(struct dm_table *t);
 int dm_table_resume_targets(struct dm_table *t);
 int dm_table_any_congested(struct dm_table *t, int bdi_bits);

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index e1707de..ca6d2ac 100644 (file)
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -64,6 +64,7 @@ typedef int (*dm_request_endio_fn) (struct dm_target *ti,
                                    union map_info *map_context);
 
 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
+typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
 typedef int (*dm_preresume_fn) (struct dm_target *ti);
 typedef void (*dm_resume_fn) (struct dm_target *ti);
@@ -145,6 +146,7 @@ struct target_type {
        dm_endio_fn end_io;
        dm_request_endio_fn rq_end_io;
        dm_presuspend_fn presuspend;
+       dm_presuspend_undo_fn presuspend_undo;
        dm_postsuspend_fn postsuspend;
        dm_preresume_fn preresume;
        dm_resume_fn resume;

diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index 3315ab2..2be66f4 100644 (file)
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -267,9 +267,9 @@ enum {
 #define DM_DEV_SET_GEOMETRY    _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
 
 #define DM_VERSION_MAJOR       4
-#define DM_VERSION_MINOR       28
+#define DM_VERSION_MINOR       29
 #define DM_VERSION_PATCHLEVEL  0
-#define DM_VERSION_EXTRA       "-ioctl (2014-09-17)"
+#define DM_VERSION_EXTRA       "-ioctl (2014-10-28)"
 
 /* Status bits */
 #define DM_READONLY_FLAG       (1 << 0) /* In/Out */