From: NeilBrown <neilb@suse.de>
Date: Wed, 21 Nov 2012 05:33:40 +0000 (+1100)
Subject: md/raid5: Make sure we clear R5_Discard when discard is finished.
X-Git-Tag: v3.7-rc7~8^2~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ca64cae96037de16e4af92678814f5d4bf0c1c65;p=pandora-kernel.git

md/raid5: Make sure we clear R5_Discard when discard is finished.

commit 9e44476851e91c86c98eb92b9bc27fb801f89072
    MD: raid5 avoid unnecessary zero page for trim

change raid5 to clear R5_Discard when the complete request is
handled rather than when submitting the per-device discard request.
However it did not clear R5_Discard for the parity device.

This means that if the stripe_head was reused before it expired from
the cache, the setting would be wrong and a hang would result.

Also if the R5_Uptodate bit happens to be set, R5_Discard again
won't be cleared.  But R5_Uptodate really should be clear at this point.

So make sure R5_Discard is cleared in all cases, and clear
R5_Uptodate when a 'discard' completes.

Signed-off-by: NeilBrown <neilb@suse.de>
---

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