From e3d37faba2eb19a1d459917bbf54ac1c65711510 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Wed, 17 May 2017 15:42:00 -0600 Subject: [PATCH] Btrfs: tolerate errors if we have retried successfully With raid1 profile, dio read isn't tolerating IO errors if read length is less than the stripe length (64K). Our bio didn't get split in btrfs_submit_direct_hook() if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED) is true and that happens when the read length is less than 64k. In this case, if the underlying device returns error somehow, bio->bi_error has recorded that error. If we could recover the correct data from another copy in profile raid1/10/5/6, with btrfs_subio_endio_read() returning 0, bio would have the correct data in its vector, but bio->bi_error is not updated accordingly so that the following dio_end_io(dio_bio, bio->bi_error) makes directIO think this read has failed. This fixes the problem by setting bio's error to 0 if a good copy has been found. Signed-off-by: Liu Bo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 96bbc836d071..147bafdb8628 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8261,8 +8261,11 @@ static void btrfs_endio_direct_read(struct bio *bio) struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); int err = bio->bi_error; - if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED) + if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED) { err = btrfs_subio_endio_read(inode, io_bio, err); + if (!err) + bio->bi_error = 0; + } unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset, dip->logical_offset + dip->bytes - 1); -- 2.20.1