From: Nate Dailey Date: Mon, 29 Feb 2016 15:43:58 +0000 (-0500) Subject: raid1: include bio_end_io_list in nr_queued to prevent freeze_array hang X-Git-Tag: v3.2.80~73 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11266d296f0376640b67a28847e613961159d907;p=pandora-kernel.git raid1: include bio_end_io_list in nr_queued to prevent freeze_array hang commit ccfc7bf1f09d6190ef86693ddc761d5fe3fa47cb upstream. If raid1d is handling a mix of read and write errors, handle_read_error's call to freeze_array can get stuck. This can happen because, though the bio_end_io_list is initially drained, writes can be added to it via handle_write_finished as the retry_list is processed. These writes contribute to nr_pending but are not included in nr_queued. If a later entry on the retry_list triggers a call to handle_read_error, freeze array hangs waiting for nr_pending == nr_queued+extra. The writes on the bio_end_io_list aren't included in nr_queued so the condition will never be satisfied. To prevent the hang, include bio_end_io_list writes in nr_queued. There's probably a better way to handle decrementing nr_queued, but this seemed like the safest way to avoid breaking surrounding code. I'm happy to supply the script I used to repro this hang. Fixes: 55ce74d4bfe1b(md/raid1: ensure device failure recorded before write request returns.) Signed-off-by: Nate Dailey Signed-off-by: Shaohua Li Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed