On Sat, Sep 16, 2017 at 01:58:34PM +0200, Goffredo Baroncelli wrote:
> On 09/15/2017 11:06 PM, Liu Bo wrote:
> > commit 4246a0b63bd8 ("block: add a bi_error field to struct bio")
> > changed the logic of how dio read endio reports errors.
> >
> > For single stripe dio read, %bio->bi_status reflects the error before
> > verifying checksum, and now we're updating it when data block matches
> > with its checksum, while in the mismatching case, %bio->bi_status is
> > not updated to relfect that.
> >
> > When some blocks in a file have been corrupted on disk, reading such a
> > file ends up with
> >
> > 1) checksum errros are reported in kernel log
> > 2) read(2) returns successfully with some content being 0x01.
> >
> > In order to fix it, we need to report its checksum mismatch error to
> > the upper layer (dio layer in this case) as well.
>
> I tested it, and now it works: even using O_DIRECT -EIO is returned if the
> file is corrupted.
>
> ghigo@venice:~/btrfs/crash-o-direct/t$ ls -li
> total 16384
> 257 -rw-r--r-- 1 root root 16777216 Sep 15 20:51 abcd
> ghigo@venice:~/btrfs/crash-o-direct/t$ date
> Sat Sep 16 13:56:26 CEST 2017
>
> ghigo@venice:~/btrfs/crash-o-direct/t$ cat abcd
> cat: abcd: Input/output error
> ghigo@venice:~/btrfs/crash-o-direct/t$ dmesg -T | tail -1
> [Sat Sep 16 13:56:29 2017] BTRFS warning (device sdd5): csum failed root 5
> ino 257 off 0 csum 0x98f94189 expected csum 0x0ab6be80 mirror 1
>
> ghigo@venice:~/btrfs/crash-o-direct/t$ dd if=abcd iflag=direct
> dd: error reading 'abcd': Input/output error
> 0+0 records in
> 0+0 records out
> 0 bytes copied, 0.000404156 s, 0.0 kB/s
> ghigo@venice:~/btrfs/crash-o-direct/t$ dmesg -T | tail -1
> [Sat Sep 16 13:56:41 2017] BTRFS warning (device sdd5): csum failed root 5
> ino 257 off 0 csum 0x98f94189 expected csum 0x0ab6be80 mirror 1
>
Thanks a lot, any chance I can get your 'Tested-by' tag?
Thanks,
-liubo
>
>
>
> >
> > Signed-off-by: Liu Bo <bo.li....@oracle.com>
> > Reported-by: Goffredo Baroncelli <kreij...@inwind.it>
> > cc: Goffredo Baroncelli <kreij...@inwind.it>
> > ---
> > fs/btrfs/inode.c | 7 ++-----
> > 1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> > index 24bcd5c..a46799e 100644
> > --- a/fs/btrfs/inode.c
> > +++ b/fs/btrfs/inode.c
> > @@ -8267,11 +8267,8 @@ static void btrfs_endio_direct_read(struct bio *bio)
> > struct btrfs_io_bio *io_bio = btrfs_io_bio(bio);
> > blk_status_t err = bio->bi_status;
> >
> > - 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_status = 0;
> > - }
> >
> > unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
> > dip->logical_offset + dip->bytes - 1);
> > @@ -8279,7 +8276,7 @@ static void btrfs_endio_direct_read(struct bio *bio)
> >
> > kfree(dip);
> >
> > - dio_bio->bi_status = bio->bi_status;
> > + dio_bio->bi_status = err;
> > dio_end_io(dio_bio);
> >
> > if (io_bio->end_io)
> >
>
>
> --
> gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it>
> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
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