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From: Amir Goldstein <amir73il@gmail.com>
Date: Fri, 20 Oct 2017 06:18:38 +0300
Message-ID: <CAOQ4uxiHDWJBcqxPjznP2oyNRruGreM7J8AUoRHr_FDk3VVajQ@mail.gmail.com>
Subject: Re: [PATCH 17/17] Add the parent pointer support to the superblock
 version 5.
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To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Allison Henderson <allison.henderson@oracle.com>, linux-xfs <linux-xfs@vger.kernel.org>, Mark Tinguely <tinguely@sgi.com>, Dave Chinner <dchinner@redhat.com>

On Thu, Oct 19, 2017 at 11:06 PM, Darrick J. Wong
<darrick.wong@oracle.com> wrote:
> On Thu, Oct 19, 2017 at 06:57:04AM +0300, Amir Goldstein wrote:
>> On Thu, Oct 19, 2017 at 1:55 AM, Allison Henderson
>> <allison.henderson@oracle.com> wrote:
>> > [dchinner: forward ported and cleaned up]
>> > [achender: rebased and added parent pointer attribute to
>> >            compatible attributes mask]
>> >
>> > Signed-off-by: Mark Tinguely <tinguely@sgi.com>
>> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
>> > Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> > ---
>> > v2: remove unrelated type clean up in xfs_format.h
>>
>> I'm curious how XFS_SB_VERSION2_PARENTBIT fits into the picture?
>> old relic?
>
> A feature bit most probably used by the SGI XFS parent pointer
> implementation.  We don't want to reuse that bit and thereby crash into
> their code.
>

Ah, I was not aware that parallel universe exists.
Perhaps worth a comment near definition of XFS_SB_VERSION2_PARENTBIT
so it won't be confused with Linux parent pointers.

Amir.