From: NeilBrown <neilb@suse.de>
Date: Thu, 14 Nov 2013 04:16:15 +0000 (+1100)
Subject: md: fix calculation of stacking limits on level change.
X-Git-Tag: v3.13-rc1~31^2~17
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=02e5f5c0a0f726e66e3d8506ea1691e344277969;p=pandora-kernel.git

md: fix calculation of stacking limits on level change.

The various ->run routines of md personalities assume that the 'queue'
has been initialised by the blk_set_stacking_limits() call in
md_alloc().

However when the level is changed (by level_store()) the ->run routine
for the new level is called for an array which has already had the
stacking limits modified.  This can result in incorrect final
settings.

So call blk_set_stacking_limits() before ->run in level_store().

A specific consequence of this bug is that it causes
discard_granularity to be set incorrectly when reshaping a RAID4 to a
RAID0.

This is suitable for any -stable kernel since 3.3 in which
blk_set_stacking_limits() was introduced.

Cc: stable@vger.kernel.org (3.3+)
Reported-and-tested-by: "Baldysiak, Pawel" <pawel.baldysiak@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
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