| Message ID | 1492132316-3076-1-git-send-email-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Apr 13, 2017 at 06:11:56PM -0700, Liu Bo wrote: > With raid1 profile, dio read isn't tolerating IO errors if read length is > less than the stripe length (64K). Can you please write more details why this is true? Some pointers to code etc, I'm lost. Eg. where the errors is tolerated. Thanks. > This fixes the problem by setting bio's error to 0 if a good copy has been > found. > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > --- > 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 632b616..4e1398e 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -8113,8 +8113,11 @@ 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); > -- > 2.5.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, May 05, 2017 at 06:52:45PM +0200, David Sterba wrote: > On Thu, Apr 13, 2017 at 06:11:56PM -0700, Liu Bo wrote: > > With raid1 profile, dio read isn't tolerating IO errors if read length is > > less than the stripe length (64K). > > Can you please write more details why this is true? Some pointers to > code etc, I'm lost. Eg. where the errors is tolerated. Thanks. Sure. Our bio didn't get split in btrfs_submit_direct_hook() if (dip->flags & BTRFS_DIO_ORIG_BIO_SUBMITTED) is true. 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. Thanks, -liubo > > > This fixes the problem by setting bio's error to 0 if a good copy has been > > found. > > > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > > --- > > 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 632b616..4e1398e 100644 > > --- a/fs/btrfs/inode.c > > +++ b/fs/btrfs/inode.c > > @@ -8113,8 +8113,11 @@ 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); > > -- > > 2.5.5 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, May 09, 2017 at 12:40:53PM -0700, Liu Bo wrote: > On Fri, May 05, 2017 at 06:52:45PM +0200, David Sterba wrote: > > On Thu, Apr 13, 2017 at 06:11:56PM -0700, Liu Bo wrote: > > > With raid1 profile, dio read isn't tolerating IO errors if read length is > > > less than the stripe length (64K). > > > > Can you please write more details why this is true? Some pointers to > > code etc, I'm lost. Eg. where the errors is tolerated. Thanks. > > Sure. > > Our bio didn't get split in btrfs_submit_direct_hook() if (dip->flags & > BTRFS_DIO_ORIG_BIO_SUBMITTED) is true. 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. Great, thanks. Please update the patch and resend. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 632b616..4e1398e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8113,8 +8113,11 @@ 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);
With raid1 profile, dio read isn't tolerating IO errors if read length is less than the stripe length (64K). This fixes the problem by setting bio's error to 0 if a good copy has been found. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/inode.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)