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Date:   Mon, 2 Dec 2019 10:29:04 +1100
From:   Dave Chinner <david@fromorbit.com>
To:     Alex Lyakas <alex@zadara.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Eric Sandeen <sandeen@sandeen.net>,
        Brian Foster <bfoster@redhat.com>, linux-xfs@vger.kernel.org
Subject: Re: [RFC-PATCH] xfs: do not update sunit/swidth in the superblock to
 match those provided during mount
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On Sun, Dec 01, 2019 at 11:00:32AM +0200, Alex Lyakas wrote:
> We can definitely adhere to the recommended behavior of setting
> sunit/swidth=1 during mkfs, provided the repair still works after
> mounting with different sunit/swidth.

FWIW, sunit/sw=1fsb doesn't work reliably either, if you grow the
sunit by a large enough value that it changes the alignment of the
root inode....

Essentially, there is no magic bullet here. We need to ensure that
the kernel doesn't do something that breaks assumptions about root
inode location, and we need to fix xfs_repair not to trash the root
inode without first checking that the current root inode pointer is
invalid...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com