Re: [PATCH 14/14] xfs: enable non-blocking timestamp updates

Dave Chinner
2025-11-16T08:23:15Z

On Fri, Nov 14, 2025 at 07:26:17AM +0100, Christoph Hellwig wrote:
> The lazytime path using generic_update_time can never block in XFS
> because there is no ->dirty_inode method that could block. Allow
> non-blocking timestamp updates for this case.
>
> Fixes: 66fa3cedf16a ("fs: Add async write file modification handling.")
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/xfs_iops.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index bd0b7e81f6ab..3d7b89ffacde 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -1195,9 +1195,6 @@ xfs_vn_update_time(
>
> trace_xfs_update_time(ip);
>
> - if (flags & S_NOWAIT)
> - return -EAGAIN;
> -
> if (inode->i_sb->s_flags & SB_LAZYTIME) {
> if (!((flags & S_VERSION) &&
> inode_maybe_inc_iversion(inode, false)))
> @@ -1207,6 +1204,9 @@ xfs_vn_update_time(
> log_flags |= XFS_ILOG_CORE;
> }
>
> + if (flags & S_NOWAIT)
> + return -EAGAIN;
> +
> error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
> if (error)
> return error;

Not sure this is correct - this can now bump iversion and then
return -EAGAIN. That means S_VERSION likely won't be set on the
retry, and we'll go straight through the non-blocking path to
generic_update_time() and skip logging the iversion update....

-Dave.
--
Dave Chinner
david@fromorbit.com