From d0852df543e5aa7db34c1ad26d053782bcbf48f1 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 27 May 2015 08:43:45 +1000 Subject: [PATCH] md/raid5: close race between STRIPE_BIT_DELAY and batching. When we add a write to a stripe we need to make sure the bitmap bit is set. While doing that the stripe is not locked so it could be added to a batch after which further changes to STRIPE_BIT_DELAY and ->bm_seq are ineffective. So we need to hold off adding to a stripe until bitmap_startwrite has completed at least once, and we need to avoid further changes to STRIPE_BIT_DELAY once the stripe has been added to a batch. If a bitmap_startwrite() completes after the stripe was added to a batch, it will not have set the bit, only incremented a counter, so no extra delay of the stripe is needed. Reported-by: Shaohua Li Signed-off-by: NeilBrown --- Reading git-format-patch failed