From 41a336e011887f73e7c879b60e1e3544045435cb Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 14 Jan 2014 11:56:14 +1100 Subject: [PATCH] md/raid1: fix request counting bug in new 'barrier' code. The new iobarrier implementation in raid1 (which keeps normal writes and resync activity separate) counts every request what is not before the current resync point in either next_window_requests or current_window_requests. It flags that the request is counted by setting ->start_next_window. allow_barrier follows this model exactly and decrements one of the *_window_requests if and only if ->start_next_window is set. However wait_barrier(), which increments *_window_requests uses a slightly different test for setting -.start_next_window (which is set from the return value of this function). So there is a possibility of the counts getting out of sync, and this leads to the resync hanging. So change wait_barrier() to return a non-zero value in exactly the same cases that it increments *_window_requests. But was introduced in 3.13-rc1. Reported-by: Bruno Wolff III URL: https://bugzilla.kernel.org/show_bug.cgi?id=68061 Fixes: 79ef3a8aa1cb1523cc231c9a90a278333c21f761 Cc: majianpeng Signed-off-by: NeilBrown --- drivers/md/raid1.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 1e5a540995e9..a49cfcc7a343 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -924,9 +924,8 @@ static sector_t wait_barrier(struct r1conf *conf, struct bio *bio) conf->next_window_requests++; else conf->current_window_requests++; - } - if (bio->bi_sector >= conf->start_next_window) sector = conf->start_next_window; + } } conf->nr_pending++; -- 2.20.1