Re: [PATCH] btrfs: fix the folio leak on S390 hardware acceleration

[Mikhail Zaslonko <zaslonko@linux.ibm.com>]

Hello Qu,

Sorry for the late response. 
I ran some test on s390 including folio-leak verification. LGTM.

Tested-by:   Mikhail Zaslonko <zaslonko@linux.ibm.com>


On 20-Jan-26 23:52, Qu Wenruo wrote:
> Adding S390 to the mailing list, I got the incorrect address in the initial patch.
> 
> Much appreciated if S390 people can give it a test.
> 
> Thanks,
> Qu
> 
> 
> 在 2026/1/19 16:24, Qu Wenruo 写道:
>> [BUG]
>> After commit aa60fe12b4f4 ("btrfs: zlib: refactor S390x HW acceleration
>> buffer preparation"), we no longer release the folio of the page cache
>> of folio returned by btrfs_compress_filemap_get_folio() for S390
>> hardware accerlation path.
>>
>> [CAUSE]
>> Before that commit, we call kumap_local() and folio_put() after handling
>> each folio.
>>
>> Although the timing is not ideal (it release previous folio at the
>> beginning of the loop, and rely on some extra cleanup out of the loop),
>> it at least handles the folio release correctly.
>>
>> Meanwhile the refactored code is easier to read, it lacks the call to
>> release the filemap folio.
>>
>> [FIX]
>> Add the missing folio_put() for copy_data_into_buffer().
>>
>> Cc: linux-s390@vger.kernel.orgaa60fe12b4f49f49fc73e5023f8675e2df1f7805
>> Fixes: aa60fe12b4f4 ("btrfs: zlib: refactor S390x HW acceleration buffer preparation")
>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>> ---
>>   fs/btrfs/zlib.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
>> index 6caba8be7c84..10ed48d4a846 100644
>> --- a/fs/btrfs/zlib.c
>> +++ b/fs/btrfs/zlib.c
>> @@ -139,6 +139,7 @@ static int copy_data_into_buffer(struct address_space *mapping,
>>           data_in = kmap_local_folio(folio, offset);
>>           memcpy(workspace->buf + cur - filepos, data_in, copy_length);
>>           kunmap_local(data_in);
>> +        folio_put(folio);
>>           cur += copy_length;
>>       }
>>       return 0;
> 
>