From: NeilBrown Date: Tue, 16 Jul 2013 06:50:47 +0000 (+1000) Subject: md/raid10: fix two problems with RAID10 resync. X-Git-Tag: v3.10.3~51 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2dc04d3333049098691eb652e06d52fbd80771d2;p=platform%2Fkernel%2Flinux-3.10.git md/raid10: fix two problems with RAID10 resync. 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 Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index d7bad6b..d61eb7e 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2075,11 +2075,17 @@ 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); @@ -3385,6 +3391,7 @@ 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); } }