From: Eric Work Date: Mon, 18 May 2015 23:26:23 -0700 Subject: md/raid0: fix restore to sector variable in raid0_make_request Origin: http://git.neil.brown.name/?p=md.git;a=commitdiff;h=a81157768a00e8cf8a7b43b5ea5cac931262374f Bug: https://bugzilla.kernel.org/show_bug.cgi?id=98501 Bug-Debian: https://bugs.debian.org/786372 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 Fixes: 47d68979cc96 ("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 --- drivers/md/raid0.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -517,6 +517,9 @@ static void raid0_make_request(struct md ? (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 md split = bio; } - sector = bio->bi_iter.bi_sector; zone = find_zone(mddev->private, §or); tmp_dev = map_sector(mddev, zone, sector, §or); split->bi_bdev = tmp_dev->bdev;