dm thin metadata: decrement counter after removing mapped block

Correct the number of mapped sectors shown on a thin device's
status line by decrementing td->mapped_blocks in __remove() each time
a block is removed.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 05b7ffc030ed..237571af77fd 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -1224,6 +1224,8 @@ static int __remove(struct dm_thin_device *td, dm_block_t block)
         if (r)
                 return r;
 
+        td->mapped_blocks--;
+        td->changed = 1;
         pmd->need_commit = 1;
 
         return 0;