Re: [dm-devel] [node-devel] [ovirt-devel] blockdev --flushbufs required [was: parted issue/question

[Jim Meyering <jim meyering net>]

Alan Pevec wrote:

>> On Wed, 2012-01-18 at 14:44 +0100, Jim Meyering wrote:
>>> [Following up on this thread:
>>>  http://thread.gmane.org/gmane.linux.kernel.device-mapper.devel/14999]
>>> Alasdair G Kergon wrote:
>>> > Try
>>> >   blkdev --flushbufs
>>> > after any cmd that writes to a dev to see if that makes any difference.
>>>
>>> Thanks for the work-around.
>>> Using "blockdev --flushbufs $dev" does indeed make parted
>>> behave the same with dm-backed storage as with other devices.
>
> Thanks Jim!
> That reminds me we've already seen something similar and there's still
> workaround with drop_caches in ovirt-config-boot installer:
>             # flush to sync DM and blockdev, workaround from rhbz#623846#c14
>             echo 3 > /proc/sys/vm/drop_caches
>
> But 623846 was supposed to be fixed in RHEL 6.0 ?

FYI, Niels de Vos has just posted a patch that should fix this:

  http://thread.gmane.org/gmane.linux.kernel/1241227

With that, maybe you'll be able to remove that other work-around.