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Commit 62de608d authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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[PATCH] md: Improve detection of lack of barrier support in raid1 



Move the test for 'do barrier work' down a bit so that if the first write to a
raid1 is a BIO_RW_BARRIER write, the checking done by superblock writes will
cause the right thing to happen.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bea27718

drivers/md/raid1.c

+11 −5
Original line number Diff line number Diff line
@@ -753,18 +753,24 @@ static int make_request(request_queue_t *q, struct bio * bio) 
	const int rw = bio_data_dir(bio);

	int do_barriers;



	if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {

		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);

		return 0;

	}



	/*

	 * Register the new request and wait if the reconstruction

	 * thread has put up a bar for new requests.

	 * Continue immediately if no resync is active currently.

	 * We test barriers_work *after* md_write_start as md_write_start

	 * may cause the first superblock write, and that will check out

	 * if barriers work.

	 */



	md_write_start(mddev, bio); /* wait on superblock update early */



	if (unlikely(!mddev->barriers_work && bio_barrier(bio))) {

		if (rw == WRITE)

			md_write_end(mddev);

		bio_endio(bio, bio->bi_size, -EOPNOTSUPP);

		return 0;

	}



	wait_barrier(conf);



	disk_stat_inc(mddev->gendisk, ios[rw]);