On Mon, 15 Jul 2013 10:35:07 -0500 Brassow Jonathan <jbrassow@xxxxxxxxxx>
wrote:
>
> On Jun 25, 2013, at 1:32 AM, NeilBrown wrote:
>
> > On Tue, 25 Jun 2013 01:19:20 -0500 Jonathan Brassow <jbrassow@xxxxxxxxxx>
> > wrote:
> >
> >> Neil,
> >>
> >> I've noticed that the "check" operation no longer works for RAID10. It
> >> works just fine for the other RAIDs. The ("data-check") sync_thread
> >> kicks off just fine, sync_request_write() is called, but it never gets
> >> past:
> >> if (i == conf->copies)
> >> goto done;
> >> The test I am performing creates a RAID array, waits for it to sync,
> >> shuts it down, writes random data to one of the devices, assembles the
> >> array, and then runs a "check" - there should be descrepancies. The
> >> descrepancies are found and recorded in resync_mismatches for all RAIDs
> >> <= 3.9 and only for non-RAID10 3.10-rc1+.
> >
> > I just tried on 3.10-rc5+ and it works as expected.
> > If you can provide a test script that fails, I'll look into it.
>
> Just tried 3.10 - it fails for me there too. I'll send you the script I use shortly.
>
> thanks,
> brassow
>
> (vacation ends soon.)
:-)
Thanks. This patch seems to fix it.
NeilBrown
From b0b0ac3ecf1e54dd6a429294082c47f1e52db41d Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@xxxxxxx>
Date: Tue, 16 Jul 2013 16:50:47 +1000
Subject: [PATCH] md/raid10: fix two problems with RAID10 resync.
1/ When an different between blocks is found, data is copied from
one bio to the other. However bv_len is used as the length to
copy and this could be zero. So use r10_bio->sectors to calculate
length instead.
Using bv_len was probably always a bit dubious, but the introduction
of bio_advance made it much more likely to be a problem.
2/ When preparing some blocks for sync, we don't set BIO_UPTODATE
except on bios that we schedule for a read. This ensures that
missing/failed devices don't confuse the loop at the top of
sync_request write.
Commit 8be185f2c9d54d6 "raid10: Use bio_reset()"
removed a loop which set BIO_UPTDATE on all appropriate bios.
So we need to re-add that flag.
Reported-by: Brassow Jonathan <jbrassow@xxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index cd066b6..957a719 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2097,11 +2097,17 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
* both 'first' and 'i', so we just compare them.
* All vec entries are PAGE_SIZE;
*/
- for (j = 0; j < vcnt; j++)
+ int sectors = r10_bio->sectors;
+ for (j = 0; j < vcnt; j++) {
+ int len = PAGE_SIZE;
+ if (sectors < (len / 512))
+ len = sectors * 512;
if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
page_address(tbio->bi_io_vec[j].bv_page),
- fbio->bi_io_vec[j].bv_len))
+ len))
break;
+ sectors -= len/512;
+ }
if (j == vcnt)
continue;
atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
@@ -3407,6 +3413,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
if (bio->bi_end_io == end_sync_read) {
md_sync_acct(bio->bi_bdev, nr_sectors);
+ set_bit(BIO_UPTODATE, &bio->bi_flags);
generic_make_request(bio);
}
}
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