dm-era: fix shadowed superblock leak on take-snap failure

metadata_take_snap() bumps the live superblock refcount and then
dm_tm_shadow_block() allocates a new block for the metadata snapshot.
If the subsequent dm_sm_inc_block() of writeset_tree_root or
era_array_root fails, the function only unlocks the clone and
returns.  The newly allocated shadow block is never returned to the
metadata space map, so each failed take-snap permanently leaks one
metadata block.

Free the clone with dm_sm_dec_block() on those error paths, matching
the final step of metadata_drop_snap().

Fixes: eec40579d848 ("dm: add era target")
Cc: stable@vger.kernel.org
Signed-off-by: liyouhong <liyouhong@kylinos.cn>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

0 files changed, 0 insertions, 0 deletions