md/raid0: fix restore to sector variable in raid0_make_request

commit a81157768a00e8cf8a7b43b5ea5cac931262374f upstream.

The variable "sector" in "raid0_make_request()" was improperly updated
by a call to "sector_div()" which modifies its first argument in place.
Commit 47d68979cc968535cb87f3e5f2e6a3533ea48fbd restored this variable
after the call for later re-use.  Unfortunetly the restore was done after
the referenced variable "bio" was advanced.  This lead to the original
value and the restored value being different.  Here we move this line to
the proper place.

One observed side effect of this bug was discarding a file though
unlinking would cause an unrelated file's contents to be discarded.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: 47d68979cc96 ("md/raid0: fix bug with chunksize not a power of 2.")
URL: https://bugzilla.kernel.org/show_bug.cgi?id=98501
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 3b5d7f704aa346ad27b4806c9e36ee9ba984edc7..903391ce93537a2292657fc5a6a901af2ffc0562 100644 (file)
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -517,6 +517,9 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
                         ? (sector & (chunk_sects-1))
                         : sector_div(sector, chunk_sects));
 
+               /* Restore due to sector_div */
+               sector = bio->bi_iter.bi_sector;
+
                if (sectors < bio_sectors(bio)) {
                        split = bio_split(bio, sectors, GFP_NOIO, fs_bio_set);
                        bio_chain(split, bio);
@@ -524,7 +527,6 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio)
                        split = bio;
                }
 
-               sector = bio->bi_iter.bi_sector;
                zone = find_zone(mddev->private, &sector);
                tmp_dev = map_sector(mddev, zone, sector, &sector);
                split->bi_bdev = tmp_dev->bdev;