Commit a8115776 authored May 18, 2015 by Eric Work Committed by NeilBrown May 21, 2015

md/raid0: fix restore to sector variable in raid0_make_request



The variable "sector" in "raid0_make_request()" was improperly updated
by a call to "sector_div()" which modifies its first argument in place.
Commit 47d68979 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: 47d68979 ("md/raid0: fix bug with chunksize not a power of 2.")
Cc: stable@vger.kernel.org (any that received above backport)
URL: https://bugzilla.kernel.org/show_bug.cgi?id=98501

parent 48769695

drivers/md/raid0.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -524,6 +524,9 @@ 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);
		@@ -531,7 +534,6 @@ 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;