[dm-devel] [PATCH RESEND 1/2 block#for-linus] bio, fs: update READA and SWRITE to match the corresponding BIO_RW_* bits

[Vladislav Bolkhovitin]

Jeff Moyer, on 08/05/2010 10:45 PM wrote:
> Tejun Heo<tj at kernel.org>  writes:
>
>> Commit a82afdf (block: use the same failfast bits for bio and request)
>> moved BIO_RW_* bits around such that they match up with REQ_* bits.
>> Unfortunately, fs.h hard coded READ, WRITE, READA and SWRITE as 0, 1,
>> 2 and 3, and expected them to match with BIO_RW_* bits.  READ/WRITE
>> didn't change but BIO_RW_AHEAD was moved to bit 4 instead of bit 1,
>> breaking READA and SWRITE.
>>
>> This patch updates READA and SWRITE such that they match the BIO_RW_*
>> bits again.  A follow up patch will update the definitions to directly
>> use BIO_RW_* bits so that this kind of breakage won't happen again.
>>
>> Stable: The offending commit a82afdf was released with v2.6.32, so
>> this patch should be applied to all kernels since then but it must
>> _NOT_ be applied to kernels earlier than that.
>
> Would someone be so kind as to remind me how this problem manifests
> itself?  I know I read this recently, but my memory and googling skills
> are both failing me.  :(

See http://lkml.org/lkml/2010/7/28/315 and link inside.

Vlad