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

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

drivers/md/md.c

+10 −4
Original line number Diff line number Diff line
@@ -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)