Re: [PATCH] bcachefs: support REMAP_FILE_DEDUP in bch2_remap_file_range

[Brian Foster <bfoster@redhat.com>]

On Sat, May 11, 2024 at 12:20:12AM +0000, Reed Riley wrote:
> By removing the early-exit when REMAP_FILE_DEDUP is set, we should be
> able to support the fideduperange ioctl, albeit less efficiently than if
> we handled some of the extent locking and comparison logic inside
> bcachefs.  Extent comparison logic already exists inside of
> `__generic_remap_file_range_prep`.
> 
> Signed-off-by: Reed Riley <reed@riley.engineer>
> ---

Seems reasonable:

Reviewed-by: Brian Foster <bfoster@redhat.com>

Have you run any tests just to make sure there are no surprises? If not,
it looks like xfs_io has a 'dedupe' command that would make it easy to
run a quick test or two from the command line. fstests has a bunch of
tests in the dedupe group (which I presume this patch should now allow
to run on bcachefs) as well.

Brian

>  fs/bcachefs/fs-io.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/fs/bcachefs/fs-io.c b/fs/bcachefs/fs-io.c
> index 20b40477425f..4f513f22a66a 100644
> --- a/fs/bcachefs/fs-io.c
> +++ b/fs/bcachefs/fs-io.c
> @@ -857,9 +857,6 @@ loff_t bch2_remap_file_range(struct file *file_src, loff_t pos_src,
>         if (remap_flags & ~(REMAP_FILE_DEDUP|REMAP_FILE_ADVISORY))
>                 return -EINVAL;
>  
> -       if (remap_flags & REMAP_FILE_DEDUP)
> -               return -EOPNOTSUPP;
> -
>         if ((pos_src & (block_bytes(c) - 1)) ||
>             (pos_dst & (block_bytes(c) - 1)))
>                 return -EINVAL;
> -- 
> 2.44.0
> 
>