Re: [PATCH v6 5/7] xfs: switch to multigrain timestamps

Darrick J. Wong
2023-08-02T17:50:03Z

On Tue, Jul 25, 2023 at 10:58:18AM -0400, Jeff Layton wrote:
> Enable multigrain timestamps, which should ensure that there is an
> apparent change to the timestamp whenever it has been written after
> being actively observed via getattr.
>
> Also, anytime the mtime changes, the ctime must also change, and those
> are now the only two options for xfs_trans_ichgtime. Have that function
> unconditionally bump the ctime, and ASSERT that XFS_ICHGTIME_CHG is
> always set.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/xfs/libxfs/xfs_trans_inode.c | 6 +++---
> fs/xfs/xfs_iops.c | 4 ++--
> fs/xfs/xfs_super.c | 2 +-
> 3 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
> index 6b2296ff248a..ad22656376d3 100644
> --- a/fs/xfs/libxfs/xfs_trans_inode.c
> +++ b/fs/xfs/libxfs/xfs_trans_inode.c
> @@ -62,12 +62,12 @@ xfs_trans_ichgtime(
> ASSERT(tp);
> ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
>
> - tv = current_time(inode);
> + /* If the mtime changes, then ctime must also change */
> + ASSERT(flags & XFS_ICHGTIME_CHG);
>
> + tv = inode_set_ctime_current(inode);
> if (flags & XFS_ICHGTIME_MOD)
> inode->i_mtime = tv;
> - if (flags & XFS_ICHGTIME_CHG)
> - inode_set_ctime_to_ts(inode, tv);
> if (flags & XFS_ICHGTIME_CREATE)
> ip->i_crtime = tv;
> }
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 3a9363953ef2..3f89ef5a2820 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -573,10 +573,10 @@ xfs_vn_getattr(
> stat->gid = vfsgid_into_kgid(vfsgid);
> stat->ino = ip->i_ino;
> stat->atime = inode->i_atime;
> - stat->mtime = inode->i_mtime;
> - stat->ctime = inode_get_ctime(inode);
> stat->blocks = XFS_FSB_TO_BB(mp, ip->i_nblocks + ip->i_delayed_blks);
>
> + fill_mg_cmtime(request_mask, inode, stat);

Huh. I would've thought @stat would come first since that's what we're
acting upon, but ... eh. :)

If everyone else is ok with the fill_mg_cmtime signature,
Acked-by: Darrick J. Wong <djwong@kernel.org>

--D

> +
> if (xfs_has_v3inodes(mp)) {
> if (request_mask & STATX_BTIME) {
> stat->result_mask |= STATX_BTIME;
> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
> index 818510243130..4b10edb2c972 100644
> --- a/fs/xfs/xfs_super.c
> +++ b/fs/xfs/xfs_super.c
> @@ -2009,7 +2009,7 @@ static struct file_system_type xfs_fs_type = {
> .init_fs_context = xfs_init_fs_context,
> .parameters = xfs_fs_parameters,
> .kill_sb = kill_block_super,
> - .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
> + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME,
> };
> MODULE_ALIAS_FS("xfs");
>
>
> --
> 2.41.0
>