From 1877db75589a895bbdc4c4c3f23558e57b521141 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 5 Feb 2014 12:17:01 +1100 Subject: [PATCH] md/raid1: restore ability for check and repair to fix read errors. commit 30bc9b53878a9921b02e3b5bc4283ac1c6de102a md/raid1: fix bio handling problems in process_checks() Move the bio_reset() to a point before where BIO_UPTODATE is checked, so that check now always report that the bio is uptodate, even if it is not. This causes process_check() to sometimes treat read-errors as successful matches so the good data isn't written out. This patch preserves the flag until it is needed. Bug was introduced in 3.11, but backported to 3.10-stable (as it fixed an even worse bug). So suitable for any -stable since 3.10. Reported-and-tested-by: Michael Tokarev Cc: stable@vger.kernel.org (3.10+) Fixed: 30bc9b53878a9921b02e3b5bc4283ac1c6de102a Signed-off-by: NeilBrown --- drivers/md/raid1.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index fd3a2a14b587..4a6ca1cb2e78 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1953,11 +1953,15 @@ static int process_checks(struct r1bio *r1_bio) for (i = 0; i < conf->raid_disks * 2; i++) { int j; int size; + int uptodate; struct bio *b = r1_bio->bios[i]; if (b->bi_end_io != end_sync_read) continue; - /* fixup the bio for reuse */ + /* fixup the bio for reuse, but preserve BIO_UPTODATE */ + uptodate = test_bit(BIO_UPTODATE, &b->bi_flags); bio_reset(b); + if (!uptodate) + clear_bit(BIO_UPTODATE, &b->bi_flags); b->bi_vcnt = vcnt; b->bi_iter.bi_size = r1_bio->sectors << 9; b->bi_iter.bi_sector = r1_bio->sector + @@ -1990,11 +1994,14 @@ static int process_checks(struct r1bio *r1_bio) int j; struct bio *pbio = r1_bio->bios[primary]; struct bio *sbio = r1_bio->bios[i]; + int uptodate = test_bit(BIO_UPTODATE, &sbio->bi_flags); if (sbio->bi_end_io != end_sync_read) continue; + /* Now we can 'fixup' the BIO_UPTODATE flag */ + set_bit(BIO_UPTODATE, &sbio->bi_flags); - if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) { + if (uptodate) { for (j = vcnt; j-- ; ) { struct page *p, *s; p = pbio->bi_io_vec[j].bv_page; @@ -2009,7 +2016,7 @@ static int process_checks(struct r1bio *r1_bio) if (j >= 0) atomic64_add(r1_bio->sectors, &mddev->resync_mismatches); if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery) - && test_bit(BIO_UPTODATE, &sbio->bi_flags))) { + && uptodate)) { /* No need to write to this device. */ sbio->bi_end_io = NULL; rdev_dec_pending(conf->mirrors[i].rdev, mddev);