Re: [PATCH v3 5/7] xfs: Switch atomic write size check in xfs_file_write_iter()

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Jan 02, 2025 at 02:04:09PM +0000, John Garry wrote:
> Currently atomic writes size permitted is fixed at the blocksize.
> 
> To start to remove this restriction, use xfs_get_atomic_write_attr() to
> find the per-inode atomic write limits and check according to that.
> 
> Signed-off-by: John Garry <john.g.garry@oracle.com>

Seems reasonable to me.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  fs/xfs/xfs_file.c | 12 +++++-------
>  fs/xfs/xfs_iops.c |  2 +-
>  fs/xfs/xfs_iops.h |  2 ++
>  3 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 2c810f75dbbd..68c22c0ab235 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -949,14 +949,12 @@ xfs_file_write_iter(
>  		return xfs_file_dax_write(iocb, from);
>  
>  	if (iocb->ki_flags & IOCB_ATOMIC) {
> -		/*
> -		 * Currently only atomic writing of a single FS block is
> -		 * supported. It would be possible to atomic write smaller than
> -		 * a FS block, but there is no requirement to support this.
> -		 * Note that iomap also does not support this yet.
> -		 */
> -		if (ocount != ip->i_mount->m_sb.sb_blocksize)
> +		unsigned int unit_min, unit_max;
> +
> +		xfs_get_atomic_write_attr(ip, &unit_min, &unit_max);
> +		if (ocount < unit_min || ocount > unit_max)
>  			return -EINVAL;
> +
>  		ret = generic_atomic_write_valid(iocb, from);
>  		if (ret)
>  			return ret;
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 207e0dadffc3..883ec45ae708 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -572,7 +572,7 @@ xfs_stat_blksize(
>  	return max_t(uint32_t, PAGE_SIZE, mp->m_sb.sb_blocksize);
>  }
>  
> -static void
> +void
>  xfs_get_atomic_write_attr(
>  	struct xfs_inode	*ip,
>  	unsigned int		*unit_min,
> diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
> index 3c1a2605ffd2..82d3ffbf7024 100644
> --- a/fs/xfs/xfs_iops.h
> +++ b/fs/xfs/xfs_iops.h
> @@ -19,5 +19,7 @@ int xfs_inode_init_security(struct inode *inode, struct inode *dir,
>  extern void xfs_setup_inode(struct xfs_inode *ip);
>  extern void xfs_setup_iops(struct xfs_inode *ip);
>  extern void xfs_diflags_to_iflags(struct xfs_inode *ip, bool init);
> +extern void xfs_get_atomic_write_attr(struct xfs_inode	*ip,
> +		unsigned int *unit_min, unsigned int *unit_max);
>  
>  #endif /* __XFS_IOPS_H__ */
> -- 
> 2.31.1
> 
>