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NeilBrown authored
md currently doesn't allow a 'sync_action' such as 'reshape' to be set while MD_RECOVERY_NEEDED is set. This s a problem, particularly since commit 738a2738 as that can cause ->check_shape to call mddev_resume() which sets MD_RECOVERY_NEEDED. So by the time we come to start 'reshape' it is very likely that MD_RECOVERY_NEEDED is still set. Testing for this flag is not really needed and is in any case very racy as it can be set at any moment - asynchronously. Any race between setting a sync_action and setting MD_RECOVERY_NEEDED must already be handled properly in some locked code, probably md_check_recovery(), so remove the test here. The test on MD_RECOVERY_RUNNING is also racy in the 'reshape' case so we should test it again after getting mddev_lock(). As this fixes a race and a regression which can cause 'reshape' to fail, it is suitable for -stable kernels since 4.1 Reported-by:
Xiao Ni <xni@redhat.com> Fixes: 738a2738 ("md/raid5: fix allocation of 'scribble' array.") Cc: stable@vger.kernel.org (v4.1+) Signed-off-by:
NeilBrown <neilb@suse.com>
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