From 30bc9b53878a9921b02e3b5bc4283ac1c6de102a Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 17 Jul 2013 15:19:29 +1000 Subject: [PATCH] md/raid1: fix bio handling problems in process_checks() Recent change to use bio_copy_data() in raid1 when repairing an array is faulty. The underlying may have changed the bio in various ways using bio_advance and these need to be undone not just for the 'sbio' which is being copied to, but also the 'pbio' (primary) which is being copied from. So perform the reset on all bios that were read from and do it early. This also ensure that the sbio->bi_io_vec[j].bv_len passed to memcmp is correct. This fixes a crash during a 'check' of a RAID1 array. The crash was introduced in 3.10 so this is suitable for 3.10-stable. Cc: stable@vger.kernel.org (3.10) Reported-by: Joe Lawrence Signed-off-by: NeilBrown --- drivers/md/raid1.c | 53 ++++++++++++++++++++++++++-------------------- 1 file changed, 30 insertions(+), 23 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index ec734588a1c6..d60412c7f995 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1849,6 +1849,36 @@ static int process_checks(struct r1bio *r1_bio) int i; int vcnt; + /* Fix variable parts of all bios */ + vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9); + for (i = 0; i < conf->raid_disks * 2; i++) { + int j; + int size; + struct bio *b = r1_bio->bios[i]; + if (b->bi_end_io != end_sync_read) + continue; + /* fixup the bio for reuse */ + bio_reset(b); + b->bi_vcnt = vcnt; + b->bi_size = r1_bio->sectors << 9; + b->bi_sector = r1_bio->sector + + conf->mirrors[i].rdev->data_offset; + b->bi_bdev = conf->mirrors[i].rdev->bdev; + b->bi_end_io = end_sync_read; + b->bi_private = r1_bio; + + size = b->bi_size; + for (j = 0; j < vcnt ; j++) { + struct bio_vec *bi; + bi = &b->bi_io_vec[j]; + bi->bv_offset = 0; + if (size > PAGE_SIZE) + bi->bv_len = PAGE_SIZE; + else + bi->bv_len = size; + size -= PAGE_SIZE; + } + } for (primary = 0; primary < conf->raid_disks * 2; primary++) if (r1_bio->bios[primary]->bi_end_io == end_sync_read && test_bit(BIO_UPTODATE, &r1_bio->bios[primary]->bi_flags)) { @@ -1857,12 +1887,10 @@ static int process_checks(struct r1bio *r1_bio) break; } r1_bio->read_disk = primary; - vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9); for (i = 0; i < conf->raid_disks * 2; i++) { int j; struct bio *pbio = r1_bio->bios[primary]; struct bio *sbio = r1_bio->bios[i]; - int size; if (sbio->bi_end_io != end_sync_read) continue; @@ -1888,27 +1916,6 @@ static int process_checks(struct r1bio *r1_bio) rdev_dec_pending(conf->mirrors[i].rdev, mddev); continue; } - /* fixup the bio for reuse */ - bio_reset(sbio); - sbio->bi_vcnt = vcnt; - sbio->bi_size = r1_bio->sectors << 9; - sbio->bi_sector = r1_bio->sector + - conf->mirrors[i].rdev->data_offset; - sbio->bi_bdev = conf->mirrors[i].rdev->bdev; - sbio->bi_end_io = end_sync_read; - sbio->bi_private = r1_bio; - - size = sbio->bi_size; - for (j = 0; j < vcnt ; j++) { - struct bio_vec *bi; - bi = &sbio->bi_io_vec[j]; - bi->bv_offset = 0; - if (size > PAGE_SIZE) - bi->bv_len = PAGE_SIZE; - else - bi->bv_len = size; - size -= PAGE_SIZE; - } bio_copy_data(sbio, pbio); } -- 2.20.1