dm space map disk: fix some book keeping in the disk space map

commit 0377a07c7a035e0d033cd8b29f0cb15244c0916a upstream.

When decrementing the reference count for a block, the free count wasn't
being updated if the reference count went to zero.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/md/persistent-data/dm-space-map-disk.c b/drivers/md/persistent-data/dm-space-map-disk.c
index cfbf9617e4658bd6aa84f45c840bda6f56a8402a..8d0a6a23438b7cdd685ea5a7c100a02c7feb84f6 100644 (file)
--- a/drivers/md/persistent-data/dm-space-map-disk.c
+++ b/drivers/md/persistent-data/dm-space-map-disk.c
@@ -140,10 +140,23 @@ static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
 
 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
 {
+       int r;
+       uint32_t old_count;
        enum allocation_event ev;
        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 
-       return sm_ll_dec(&smd->ll, b, &ev);
+       r = sm_ll_dec(&smd->ll, b, &ev);
+       if (!r && (ev == SM_FREE)) {
+               /*
+                * It's only free if it's also free in the last
+                * transaction.
+                */
+               r = sm_ll_lookup(&smd->old_ll, b, &old_count);
+               if (!r && !old_count)
+                       smd->nr_allocated_this_transaction--;
+       }
+
+       return r;
 }
 
 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)