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From: Eric Sandeen <sandeen@sandeen.net>
To: "Darrick J. Wong" <darrick.wong@oracle.com>,
	Christoph Hellwig <hch@lst.de>
Cc: Brian Foster <bfoster@redhat.com>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH] xfs: revert 1baa2800e62d ("xfs: remove the unused XFS_ALLOC_USERDATA flag")
Date: Wed, 4 Dec 2019 10:59:28 -0600
Message-ID: <368e49a7-3f7f-6270-dde4-ea110bbcaf67@sandeen.net> (raw)
In-Reply-To: <20190923235224.GW2229799@magnolia>

On 9/23/19 6:52 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Revert this commit, as it caused periodic regressions in xfs/173 w/
> 1k blocks[1].
> 
> [1] https://lore.kernel.org/lkml/20190919014602.GN15734@shao2-debian/
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Came across this randomly ... since there's no explanation in the changelog
as to /why/ this broke things, I think it's due to:

static inline bool
xfs_alloc_is_userdata(int datatype)
{
        return (datatype & ~XFS_ALLOC_NOBUSY) != 0;
}

which would previously have returned true if (datatype & XFS_ALLOC_USERDATA),
but without the any flag set returned false.  So failing to set
XFS_ALLOC_USERDATA indirectly changed the result of this test.

So, you're welcome, future code archaeologists.  :)

-Eric

      parent reply index

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-23 23:52 Darrick J. Wong
2019-09-24  9:39 ` Brian Foster
2019-09-24 21:30 ` Christoph Hellwig
2019-12-04 16:59 ` Eric Sandeen [this message]

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