From: Anand Jain Date: Sat, 14 Oct 2017 00:34:02 +0000 (+0800) Subject: btrfs: fix false EIO for missing device X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4bcbfac98d517eae6d12257aed923347be16930c;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git btrfs: fix false EIO for missing device [ Upstream commit 102ed2c5ff932439bbbe74c7bd63e6d5baa9f732 ] When one of the device is missing, bbio_error() takes care of setting the error status. And if its only IO that is pending in that stripe, it fails to check the status of the other IO at %bbio_error before setting the error %bi_status for the %orig_bio. Fix this by checking if %bbio->error has exceeded the %bbio->max_errors. Reproducer as below fdatasync error is seen intermittently. mount -o degraded /dev/sdc /btrfs dd status=none if=/dev/zero of=$(mktemp /btrfs/XXX) bs=4096 count=1 conv=fdatasync dd: fdatasync failed for ‘/btrfs/LSe’: Input/output error The reason for the intermittences of the problem is because the following conditions have to be met, which depends on timing: In btrfs_map_bio() - the RAID1 the missing device has to be at %dev_nr = 1 In bbio_error() . before bbio_error() is called the bio of the not-missing device at %dev_nr = 0 must be completed so that the below condition is true if (atomic_dec_and_test(&bbio->stripes_pending)) { Signed-off-by: Anand Jain Reviewed-by: Liu Bo Signed-off-by: David Sterba Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index b39737568c22..abc57f7b2716 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -6144,7 +6144,10 @@ static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical) btrfs_io_bio(bio)->mirror_num = bbio->mirror_num; bio->bi_iter.bi_sector = logical >> 9; - bio->bi_status = BLK_STS_IOERR; + if (atomic_read(&bbio->error) > bbio->max_errors) + bio->bi_status = BLK_STS_IOERR; + else + bio->bi_status = BLK_STS_OK; btrfs_end_bbio(bbio, bio); } }