Re: regression introduced by "block: Add support for DAX reads/writes to block devices"

From: Jeff Moyer <jmoyer@redhat.com>
To: Boaz Harrosh <boaz@plexistor.com>
Cc: "Wilcox\, Matthew R" <matthew.r.wilcox@intel.com>,
	"linda.knippers\@hp.com" <linda.knippers@hp.com>,
	"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-fsdevel\@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: regression introduced by "block: Add support for DAX reads/writes to block devices"
Date: Wed, 12 Aug 2015 17:11:36 -0400	[thread overview]
Message-ID: <x49k2t05i0n.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <55C855D5.1070001@plexistor.com> (Boaz Harrosh's message of "Mon, 10 Aug 2015 10:42:13 +0300")

Boaz Harrosh <boaz@plexistor.com> writes:

> On 08/07/2015 11:41 PM, Jeff Moyer wrote:
> <>
>> 
>>> We need to cope with the case where the end of a partition isn't on a
>>> page boundary though.
>> 
>> Well, that's usually done by falling back to buffered I/O.  I gave that
>> a try and panicked the box.  :)  I'll keep looking into it, but probably
>> won't have another patch until next week.
>> 
>
> lets slow down for a sec, please.
>
> We have all established that an unaligned partition start is BAD and not supported?

No.  Unaligned partitions on RAID arrays or 512e devices are bad because
they result in suboptimal performance.  They are most certainly still
supported, though.

-Jeff