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Date:   Wed, 13 Dec 2023 13:31:10 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     John Garry <john.g.garry@oracle.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,
        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-xfs@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, tytso@mit.edu, jbongio@google.com,
        linux-scsi@vger.kernel.org, ming.lei@redhat.com,
        jaswin@linux.ibm.com, bvanassche@acm.org,
        Prasad Singamsetty <prasad.singamsetty@oracle.com>
Subject: Re: [PATCH v2 05/16] fs: Add RWF_ATOMIC and IOCB_ATOMIC flags for
 atomic write support
Message-ID: <20231213133110.GL1674809@ZenIV>
References: <20231212110844.19698-1-john.g.garry@oracle.com>
 <20231212110844.19698-6-john.g.garry@oracle.com>
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Sender: Al Viro <viro@ftp.linux.org.uk>
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On Tue, Dec 12, 2023 at 11:08:33AM +0000, John Garry wrote:

> Add file mode flag FMODE_CAN_ATOMIC_WRITE, so files which do not have the
> flag set will have RWF_ATOMIC rejected and not just ignored.
> 
> Signed-off-by: Prasad Singamsetty <prasad.singamsetty@oracle.com>
> Signed-off-by: John Garry <john.g.garry@oracle.com>
> ---
>  include/linux/fs.h      | 8 ++++++++
>  include/uapi/linux/fs.h | 5 ++++-
>  2 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 70329c81be31..d725c194243c 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -185,6 +185,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
>  /* File supports async nowait buffered writes */
>  #define FMODE_BUF_WASYNC	((__force fmode_t)0x80000000)
>  
> +/* File supports atomic writes */
> +#define FMODE_CAN_ATOMIC_WRITE	((__force fmode_t)0x100000000)

Have you even tried to compile that on e.g. arm?