[PATCH 1/3] mm: Don't blindly assign fallback_migrate_page()

[Richard Weinberger]

Am 17.06.2016 um 01:11 schrieb Andrew Morton:
> On Thu, 16 Jun 2016 23:26:13 +0200 Richard Weinberger <richard at nod.at> wrote:
> 
>> While block oriented filesystems use buffer_migrate_page()
>> as page migration function other filesystems which don't
>> implement ->migratepage() will automatically get fallback_migrate_page()
>> assigned. fallback_migrate_page() is not as generic as is should
>> be. Page migration is filesystem specific and a one-fits-all function
>> is hard to achieve. UBIFS leaned this lection the hard way.
>> It uses various page flags and fallback_migrate_page() does not
>> handle these flags as UBIFS expected.
>>
>> To make sure that no further filesystem will get confused by
>> fallback_migrate_page() disable the automatic assignment and
>> allow filesystems to use this function explicitly if it is
>> really suitable.
> 
> hm, is there really much point in doing this?  I assume it doesn't
> actually affect any current filesystems?
> 
> [2/3] is of course OK - please add it to the UBIFS tree.

Pushed 2/3 and 3/3 into UBIFS next tree.

Thanks,
//richard