On Monday, May 13th, 2024 at 5:34 AM, Brian Foster <[email protected]> wrote:

> 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 [email protected]
> > ---
> 
> 
> Seems reasonable:
> 
> Reviewed-by: Brian Foster [email protected]
> 
> 
> 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.

I worked with Kent to run his CI tests against the patch 
(https://evilpiepirate.org/~testdashboard/ci?branch=bcachefs-fideduperange&commit=1945149c8d7549b924cd88f57f0cd938b3bb7125)
 and also used xfs_io to do some basic sanity checks.

Specifically, I sanity checked that:
 1. fideduperange doesn’t dedupe if file content doesn’t match,
 2. fideduperange does dedupe stuff when they do (according to filefrag -v 
reporting shared extents), and
 3. That neither of the above operations changed file checksums.

I’d be happy to run more tests if anyone can suggest them?

> 
> 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

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