Re: [PATCH 2/4] loop: Enable correct physical blocksize

[Ming Lei]

On Fri, Aug 7, 2015 at 4:54 AM, Hannes Reinecke <hare@xxxxxxx> wrote:
> When running on files the physical blocksize is actually 4k,
> so we should be announcing it as such. This is enabled with
> a new LO_FLAGS_BLOCKSIZE flag value to the existing ioctl.
>
> Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
> ---
>  drivers/block/loop.c      | 9 ++++++++-
>  include/uapi/linux/loop.h | 1 +
>  2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index b9e12a0..fce13bd 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -177,6 +177,8 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
>                 lo->lo_offset = offset;
>         if (lo->lo_sizelimit != sizelimit)
>                 lo->lo_sizelimit = sizelimit;
> +       if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
> +               blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
>         set_capacity(lo->lo_disk, x);
>         bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
>         /* let user-space know about the new size */
> @@ -758,7 +760,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
>
>         lo->lo_blocksize = lo_blocksize;
>         lo->lo_device = bdev;
> -       lo->lo_flags = lo_flags;
> +       lo->lo_flags |= lo_flags;

lo->lo_flags is cleared in loop_clr_fd(), and set_status() can only
be done when loop's state is bound, so why do you want to
keep previous zero flag?

>         lo->lo_backing_file = file;
>         lo->transfer = NULL;
>         lo->ioctl = NULL;
> @@ -769,6 +771,8 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
>         if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
>                 blk_queue_flush(lo->lo_queue, REQ_FLUSH);
>
> +       if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
> +               blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
>         set_capacity(lo->lo_disk, size);
>         bd_set_size(bdev, size << 9);
>         loop_sysfs_init(lo);
> @@ -951,6 +955,9 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
>         if (err)
>                 return err;
>
> +       if (info->lo_flags & LO_FLAGS_BLOCKSIZE)
> +               lo->lo_flags |= LO_FLAGS_BLOCKSIZE;
> +
>         if (lo->lo_offset != info->lo_offset ||
>             lo->lo_sizelimit != info->lo_sizelimit)
>                 if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
> diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h
> index e0cecd2..caec9d3 100644
> --- a/include/uapi/linux/loop.h
> +++ b/include/uapi/linux/loop.h
> @@ -21,6 +21,7 @@ enum {
>         LO_FLAGS_READ_ONLY      = 1,
>         LO_FLAGS_AUTOCLEAR      = 4,
>         LO_FLAGS_PARTSCAN       = 8,
> +       LO_FLAGS_BLOCKSIZE      = 16,
>  };
>
>  #include <asm/posix_types.h>   /* for __kernel_old_dev_t */
> --
> 1.8.4.5
>



-- 
Ming Lei
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/