Re: current status of zfs block_cloning on CURRENT?

On 4/24/23 21:30, Warner Losh wrote:
>
>
> On Mon, Apr 24, 2023 at 9:49 PM Charlie Li <vishwin@freebsd.org> wrote:
>
>     Charlie Li wrote:
>     > Pete Wright wrote:
>     >> i've seen a few threads about the block_cloning feature causing
>     data
>     >> corruption issues on CURRENT and have been keen to avoid
>     enabling it
>     >> until the dust settles.  i was under the impression that we either
>     >> reverted or disabled block_cloning on CURRENT, but when i ran
>     "zpool
>     >> upgrade" on a pool today it reported block_cloning was
>     enabled.  this
>     >> is on a system i rebuilt yesterday.
>     >>
>     > The dust has settled.
>     Barely...
>     >> i was hoping to get some clarity on the effect of having this
>     feature
>     >> enabled, is this enough to trigger the data corruption bug or does
>     >> something on the zfs filesystem itself have to be enabled to
>     trigger
>     >> this?
>     >>
>     > The initial problem with block_cloning [0][1] was fixed in commits
>     > e0bb199925565a3770733afd1a4d8bb2d4d0ce31 and
>     > 1959e122d9328b31a62ff7508e1746df2857b592, with a sysctl added in
>     commit
>     > 068913e4ba3dd9b3067056e832cefc5ed264b5cc. A different data
>     corruption
>     > problem [2][3] was fixed in commit
>     > 63ee747febbf024be0aace61161241b53245449e. All were committed
>     between
>     > 15-17 April.
>     >
>     > [0]
>     https://github.com/openzfs/zfs/pull/13392#issuecomment-1504239103
>     > [1] https://github.com/openzfs/zfs/pull/14739
>     > [2] https://github.com/openzfs/zfs/issues/14753
>     > [3] https://github.com/openzfs/zfs/pull/14761
>     >
>     Given mjg@'s thread reporting further crashes/panics, you may want to
>     keep the sysctl disabled if you upgraded the pool already.
>
>
> I thought the plan was to keep it disabled until after 14. And even then,
> when it comes back in, it will be a new feature It should never be 
> enabled.
>

that was my reading of things too - thanks for the tip on disabling the 
sysctl knob Charlie, I'll do that.

if this is really intended to be live i'd like to suggest we update 
zpool-features(7) at the least so others aren't caught by surprise. i'd 
propose a PR myself, but I'm not %100 clear on what its intent is.

-pete

-- 
Pete Wright
pete@nomadlogic.org
@nomadlogicLA