Commit 79bf31a3 authored by Shaohua Li's avatar Shaohua Li

md: fix a race condition for flush request handling

md_submit_flush_data calls pers->make_request, which missed the suspend check.
Fix it with the new md_handle_request API.
Reported-by: default avatarNate Dailey <nate.dailey@stratus.com>
Tested-by: default avatarNate Dailey <nate.dailey@stratus.com>
Fix: cc27b0c7(md: fix deadlock between mddev_suspend() and md_write_start())
Cc: stable@vger.kernel.org
Reviewed-by: default avatarNeilBrown <neilb@suse.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 393debc2
......@@ -447,16 +447,22 @@ static void md_submit_flush_data(struct work_struct *ws)
struct mddev *mddev = container_of(ws, struct mddev, flush_work);
struct bio *bio = mddev->flush_bio;
/*
* must reset flush_bio before calling into md_handle_request to avoid a
* deadlock, because other bios passed md_handle_request suspend check
* could wait for this and below md_handle_request could wait for those
* bios because of suspend check
*/
mddev->flush_bio = NULL;
wake_up(&mddev->sb_wait);
if (bio->bi_iter.bi_size == 0)
/* an empty barrier - all done */
bio_endio(bio);
else {
bio->bi_opf &= ~REQ_PREFLUSH;
mddev->pers->make_request(mddev, bio);
md_handle_request(mddev, bio);
}
mddev->flush_bio = NULL;
wake_up(&mddev->sb_wait);
}
void md_flush_request(struct mddev *mddev, struct bio *bio)
......
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