[PATCH] dm table: store md

Store an up-pointer to the owning struct mapped_device in every table when it
is created.

Access it with:
  struct mapped_device *dm_table_get_md(struct dm_table *t)

Tables linked to md must be destroyed before the md itself.

Signed-off-by: Mike Anderson <andmike@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 21 insertions, 11 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 0693b6f54b7d..65826bdac00c 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -244,9 +244,9 @@ static void __hash_remove(struct hash_cell *hc)
                 dm_table_put(table);
         }
 
-        dm_put(hc->md);
         if (hc->new_map)
                 dm_table_put(hc->new_map);
+        dm_put(hc->md);
         free_cell(hc);
 }
 
@@ -985,33 +985,43 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
         int r;
         struct hash_cell *hc;
         struct dm_table *t;
+        struct mapped_device *md;
+
+        md = find_device(param);
+        if (!md)
+                return -ENXIO;
 
-        r = dm_table_create(&t, get_mode(param), param->target_count);
+        r = dm_table_create(&t, get_mode(param), param->target_count, md);
         if (r)
-                return r;
+                goto out;
 
         r = populate_table(t, param, param_size);
         if (r) {
                 dm_table_put(t);
-                return r;
+                goto out;
         }
 
         down_write(&_hash_lock);
-        hc = __find_device_hash_cell(param);
-        if (!hc) {
-                DMWARN("device doesn't appear to be in the dev hash table.");
-                up_write(&_hash_lock);
+        hc = dm_get_mdptr(md);
+        if (!hc || hc->md != md) {
+                DMWARN("device has been removed from the dev hash table.");
                 dm_table_put(t);
-                return -ENXIO;
+                up_write(&_hash_lock);
+                r = -ENXIO;
+                goto out;
         }
 
         if (hc->new_map)
                 dm_table_put(hc->new_map);
         hc->new_map = t;
+        up_write(&_hash_lock);
+
         param->flags |= DM_INACTIVE_PRESENT_FLAG;
+        r = __dev_status(md, param);
+
+out:
+        dm_put(md);
 
-        r = __dev_status(hc->md, param);
-        up_write(&_hash_lock);
         return r;
 }