Re: [PATCH] dm thin metadata: fix superblock refcount leak on snapshot shadow failure

[genjian zhang]

At 2026-07-13 10:40:48, "Ming Hung Tsai" <mtsai@xxxxxxxxxx> wrote:
>On Sat, Jul 11, 2026 at 6:16 PM Genjian <zhanggenjian@xxxxxxx> wrote:
>>
>> From: Genjian Zhang <zhanggenjian@xxxxxxxxxx>
>>
>> __reserve_metadata_snap() increments THIN_SUPERBLOCK_LOCATION in the
>> metadata space map before shadowing it. When dm_tm_shadow_block()
>> fails, a reference is leaked in the metadata space map.
>>
>> Fix by adding the missing dm_sm_dec_block().
>>
>> Fixes: cc8394d86f04 ("dm thin: provide userspace access to pool metadata")
>> Signed-off-by: Genjian Zhang <zhanggenjian@xxxxxxxxxx>
>> ---
>
>The fix looks reasonable as a best-effort cleanup for the immediate
>refcount leak.

Thanks for the review.

Thanks,
Genjian