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Message-ID: <bbe9e4a6-c206-45b8-bf5a-8d19a00740c1@oracle.com>
Date: Tue, 20 Feb 2024 09:40:17 +0000
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Subject: Re: [PATCH v4 04/11] fs: Add initial atomic write support info to
 statx
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To: Dave Chinner <david@fromorbit.com>
Cc: axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me,
        jejb@linux.ibm.com, martin.petersen@oracle.com, djwong@kernel.org,
        viro@zeniv.linux.org.uk, brauner@kernel.org, dchinner@redhat.com,
        jack@suse.cz, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
        linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com,
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        linux-btrfs@vger.kernel.org, io-uring@vger.kernel.org,
        nilay@linux.ibm.com, ritesh.list@gmail.com,
        Prasad Singamsetty <prasad.singamsetty@oracle.com>
References: <20240219130109.341523-1-john.g.garry@oracle.com>
 <20240219130109.341523-5-john.g.garry@oracle.com>
 <ZdPWGwntYMvstbpc@dread.disaster.area>
From: John Garry <john.g.garry@oracle.com>
Organization: Oracle Corporation
In-Reply-To: <ZdPWGwntYMvstbpc@dread.disaster.area>
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On 19/02/2024 22:28, Dave Chinner wrote:
>>   
>> +/**
>> + * generic_fill_statx_atomic_writes - Fill in the atomic writes statx attributes
>> + * @stat:	Where to fill in the attribute flags
>> + * @unit_min:	Minimum supported atomic write length
>> + * @unit_max:	Maximum supported atomic write length
>> + *
>> + * Fill in the STATX{_ATTR}_WRITE_ATOMIC flags in the kstat structure from
>> + * atomic write unit_min and unit_max values.
>> + */
>> +void generic_fill_statx_atomic_writes(struct kstat *stat,
>> +				      unsigned int unit_min,
>> +				      unsigned int unit_max)
>> +{
>> +	/* Confirm that the request type is known */
>> +	stat->result_mask |= STATX_WRITE_ATOMIC;
>> +
>> +	/* Confirm that the file attribute type is known */
>> +	stat->attributes_mask |= STATX_ATTR_WRITE_ATOMIC;
>> +
>> +	if (unit_min) {
>> +		stat->atomic_write_unit_min = unit_min;
>> +		stat->atomic_write_unit_max = unit_max;
>> +		/* Initially only allow 1x segment */
>> +		stat->atomic_write_segments_max = 1;
>> +
>> +		/* Confirm atomic writes are actually supported */
>> +		stat->attributes |= STATX_ATTR_WRITE_ATOMIC;
>> +	}
>> +}
>> +EXPORT_SYMBOL(generic_fill_statx_atomic_writes);
> What units are these in? Nothing in the patch or commit description
> tells us....

I can append the current comments to mention that the unit is bytes.

Thanks,
John