Commit 62de608d authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[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
......@@ -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]);
......
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