This is a note to let you know that I've just added the patch titled
md/raid10: fix two problems with RAID10 resync.
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-raid10-fix-two-problems-with-raid10-resync.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 7bb23c4934059c64cbee2e41d5d24ce122285176 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@xxxxxxx>
Date: Tue, 16 Jul 2013 16:50:47 +1000
Subject: md/raid10: fix two problems with RAID10 resync.
From: NeilBrown <neilb@xxxxxxx>
commit 7bb23c4934059c64cbee2e41d5d24ce122285176 upstream.
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.
These bugs were introduced in 3.10, so this patch is suitable for
3.10-stable, and can remove a potential for data corruption.
Reported-by: Brassow Jonathan <jbrassow@xxxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/md/raid10.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2075,11 +2075,17 @@ static void sync_request_write(struct md
* 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);
@@ -3385,6 +3391,7 @@ static sector_t sync_request(struct mdde
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);
}
}
Patches currently in stable-queue which might be from neilb@xxxxxxx are
queue-3.10/md-raid10-fix-two-problems-with-raid10-resync.patch
queue-3.10/md-raid10-fix-two-bugs-affecting-raid10-reshape.patch
queue-3.10/md-raid10-fix-bug-which-causes-all-raid10-reshapes-to-move-no-data.patch
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