Re: git: 2a58b312b62f - main - zfs: merge openzfs/zfs@431083f75

On April 12, 2023 8:51:09 AM PDT, Charlie Li <vishwin@freebsd.org> wrote:
>Cy Schubert wrote:
>> I have a "sandhbox" pool, called t, used for /usr/obj and ports wrkdirs, and other writes I can easily recreate on my laptop. Here are the results of my tests.
>> 
>> Method:
>> 
>> Initially I copied my /usr/obj from my two build machines (one amd64.amd64 and an i386.i386) to my "sandbox" zpool.
>> 
>> Next, with block_cloning disabled I did cp -R of the /usr/obj test files. Then a diff -qr. They source and target directories were the same.
>> 
>> Next, I cleaned up (rm -rf) the target directory to prepare for the
>> block_clone enabled test.
>> 
>> Next, I did zpool checkpoint t. After this, zpool upgrade t. Pool t now has block_cloning enabled.
>> 
>> I repeated the cp -R test from above followed by a diff -qr. Almost
>> every file was different. The pool was corrupted.
>> 
>> I restored the pool by the following removing the corruption:
>> 
>> 
>> slippy# zpool export t
>> slippy# zpool import --rewind-to-checkpoint t
>> slippy#
>> 
>> It is recommended that people avoid upgrading their zpools until the
>> problem is fixed.
>> 
>As of af7624ed3145, I just did this with an md(4)-backed test pool, though with the second `cp -R` landing in a separate dataset, created and destroyed for each test. No corruption either way. However, my poudriere builds still output/package corrupted files (particularly those with null characters), probably after install(1) invocations (not cp(1)).
>

You need to copy from/to the same dataset to reproduce the problem. Copying from a source dataset to a different dataset will avoid block_cloning.


-- 
Cheers,
Cy Schubert <Cy.Schubert@cschubert.com>
FreeBSD UNIX:  <cy@FreeBSD.org>  Web:  https://FreeBSD.org
NTP:                     <cy@nwtime.org>    Web:  https://nwtime.org
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Pardon the typos. Small keyboard in use.