Re: [PATCH v2 02/11] xfs: Switch atomic write size check in xfs_file_write_iter()

Darrick J. Wong
2025-02-24T20:24:57Z

On Thu, Feb 13, 2025 at 01:56:10PM +0000, John Garry wrote:
> Currently the size of atomic write allowed is fixed at the blocksize.
>
> To start to lift this restriction, refactor xfs_get_atomic_write_attr()
> to into a helper - xfs_report_atomic_write() - and use that helper to
> find the per-inode atomic write limits and check according to that.
>
> Signed-off-by: John Garry <john.g.garry@oracle.com>

Looks fine,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
> fs/xfs/xfs_file.c | 12 +++++-------
> fs/xfs/xfs_iops.c | 20 +++++++++++++++++---
> fs/xfs/xfs_iops.h | 3 +++
> 3 files changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index f7a7d89c345e..258c82cbce12 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -853,14 +853,12 @@ 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 40289fe6f5b2..ea79fb246e33 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -600,15 +600,29 @@ xfs_report_dioalign(
> stat->dio_offset_align = stat->dio_read_offset_align;
> }
>
> +void
> +xfs_get_atomic_write_attr(
> + struct xfs_inode *ip,
> + unsigned int *unit_min,
> + unsigned int *unit_max)
> +{
> + if (!xfs_inode_can_atomicwrite(ip)) {
> + *unit_min = *unit_max = 0;
> + return;
> + }
> +
> + *unit_min = *unit_max = ip->i_mount->m_sb.sb_blocksize;
> +}
> +
> static void
> xfs_report_atomic_write(
> struct xfs_inode *ip,
> struct kstat *stat)
> {
> - unsigned int unit_min = 0, unit_max = 0;
> + unsigned int unit_min, unit_max;
> +
> + xfs_get_atomic_write_attr(ip, &unit_min, &unit_max);
>
> - if (xfs_inode_can_atomicwrite(ip))
> - unit_min = unit_max = ip->i_mount->m_sb.sb_blocksize;
> generic_fill_statx_atomic_writes(stat, unit_min, unit_max);
> }
>
> diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
> index 3c1a2605ffd2..ce7bdeb9a79c 100644
> --- a/fs/xfs/xfs_iops.h
> +++ b/fs/xfs/xfs_iops.h
> @@ -19,5 +19,8 @@ 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);
> +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
>
>