From: Eric Mei <meijia@gmail.com>
To: linux-raid@vger.kernel.org
Subject: write barrier in RAID5
Date: Wed, 01 Apr 2015 12:24:38 -0600 [thread overview]
Message-ID: <551C37E6.6090201@gmail.com> (raw)
I can see how FUA is handled, but REQ_FLUSH seems problematic. My
understanding of REQ_FLUSH semantics: all requests before the flush
request must *complete* before the flush request complete. For IO remap
layer like MD, we need to guarantee all previous requests are
*submitted* to component devices before submitting the flush request. Is
that correct?
If so why I don't see the code which make sure the pending write
requests in stripe cache are processed & submitted before
submit_flushes() get called? Thanks
Eric
next reply other threads:[~2015-04-01 18:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-01 18:24 Eric Mei [this message]
2015-04-07 1:25 ` write barrier in RAID5 NeilBrown
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