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Date: Thu, 3 Oct 2024 15:02:58 +0200
From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: axboe@kernel.dk, brauner@kernel.org, djwong@kernel.org,
	viro@zeniv.linux.org.uk, jack@suse.cz, dchinner@redhat.com,
	hch@lst.de, cem@kernel.org, linux-block@vger.kernel.org,
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	martin.petersen@oracle.com, catherine.hoang@oracle.com,
	mcgrof@kernel.org, ritesh.list@gmail.com, ojaswin@linux.ibm.com
Subject: Re: [PATCH v6 4/7] xfs: Support FS_XFLAG_ATOMICWRITES
Message-ID: <20241003130258.GA18099@lst.de>
References: <20240930125438.2501050-1-john.g.garry@oracle.com> <20240930125438.2501050-5-john.g.garry@oracle.com> <06344e9f-a625-4f6e-8b23-329ee8ebf67f@oracle.com>
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On Thu, Oct 03, 2024 at 01:48:41PM +0100, John Garry wrote:
> On 30/09/2024 13:54, John Garry wrote:
>> @@ -352,11 +352,15 @@ xfs_sb_has_compat_feature(
>>   #define XFS_SB_FEAT_RO_COMPAT_RMAPBT   (1 << 1)		/* reverse map btree */
>>   #define XFS_SB_FEAT_RO_COMPAT_REFLINK  (1 << 2)		/* reflinked files */
>>   #define XFS_SB_FEAT_RO_COMPAT_INOBTCNT (1 << 3)		/* inobt block counts */
>> +#define XFS_SB_FEAT_RO_COMPAT_ATOMICWRITES (1 << 31)	/* atomicwrites enabled */
>> +
>
> BTW, Darrick, as you questioned previously, this does make xfs/270 fail... 
> until the change to a not use the top bit.

With the large block size based atomic writes we shoudn't even need
a feature flag, or am I missing something?