From: NeilBrown Date: Sun, 1 Feb 2015 23:44:29 +0000 (+1100) Subject: md/raid5: fix another livelock caused by non-aligned writes. X-Git-Tag: fixes-v4.0-rc1~209^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1b02fe97f75b12ab34b2303bfd4e3526d903a58;p=pandora-kernel.git md/raid5: fix another livelock caused by non-aligned writes. If a non-page-aligned write is destined for a device which is missing/faulty, we can deadlock. As the target device is missing, a read-modify-write cycle is not possible. As the write is not for a full-page, a recontruct-write cycle is not possible. This should be handled by logic in fetch_block() which notices there is a non-R5_OVERWRITE write to a missing device, and so loads all blocks. However since commit 67f455486d2ea2, that code requires STRIPE_PREREAD_ACTIVE before it will active, and those circumstances never set STRIPE_PREREAD_ACTIVE. So: in handle_stripe_dirtying, if neither rmw or rcw was possible, set STRIPE_DELAYED, which will cause STRIPE_PREREAD_ACTIVE be set after a suitable delay. Fixes: 67f455486d2ea20b2d94d6adf5b9b783d079e321 Cc: stable@vger.kernel.org (v3.16+) Reported-by: Mikulas Patocka Tested-by: Heinz Mauelshagen Signed-off-by: NeilBrown --- Reading git-diff-tree failed