On Mon, 2022-08-22 at 09:57 +1000, NeilBrown wrote:
> On Fri, 19 Aug 2022, Jeff Layton wrote:
> > xfs will update the i_version when updating only the atime value, which
> > is not desirable for any of the current consumers of i_version. Doing so
> > leads to unnecessary cache invalidations on NFS and extra measurement
> > activity in IMA.
> >
> > Add a new XFS_ILOG_NOIVER flag, and use that to indicate that the
> > transaction should not update the i_version. Set that value in
> > xfs_vn_update_time if we're only updating the atime.
> >
> > Cc: Dave Chinner <david@xxxxxxxxxxxxx>
> > Cc: NeilBrown <neilb@xxxxxxx>
> > Cc: Trond Myklebust <trondmy@xxxxxxxxxxxxxxx>
> > Cc: David Wysochanski <dwysocha@xxxxxxxxxx>
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > ---
> > fs/xfs/libxfs/xfs_log_format.h | 2 +-
> > fs/xfs/libxfs/xfs_trans_inode.c | 2 +-
> > fs/xfs/xfs_iops.c | 10 +++++++---
> > 3 files changed, 9 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h
> > index b351b9dc6561..866a4c5cf70c 100644
> > --- a/fs/xfs/libxfs/xfs_log_format.h
> > +++ b/fs/xfs/libxfs/xfs_log_format.h
> > @@ -323,7 +323,7 @@ struct xfs_inode_log_format_32 {
> > #define XFS_ILOG_ABROOT 0x100 /* log i_af.i_broot */
> > #define XFS_ILOG_DOWNER 0x200 /* change the data fork owner on replay */
> > #define XFS_ILOG_AOWNER 0x400 /* change the attr fork owner on replay */
> > -
> > +#define XFS_ILOG_NOIVER 0x800 /* don't bump i_version */
> >
> > /*
> > * The timestamps are dirty, but not necessarily anything else in the inode
> > diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
> > index 8b5547073379..ffe6d296e7f9 100644
> > --- a/fs/xfs/libxfs/xfs_trans_inode.c
> > +++ b/fs/xfs/libxfs/xfs_trans_inode.c
> > @@ -126,7 +126,7 @@ xfs_trans_log_inode(
> > * unconditionally.
> > */
> > if (!test_and_set_bit(XFS_LI_DIRTY, &iip->ili_item.li_flags)) {
> > - if (IS_I_VERSION(inode) &&
> > + if (!(flags & XFS_ILOG_NOIVER) && IS_I_VERSION(inode) &&
> > inode_maybe_inc_iversion(inode, flags & XFS_ILOG_CORE))
> > iversion_flags = XFS_ILOG_CORE;
> > }
> > diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> > index 45518b8c613c..54db85a43dfb 100644
> > --- a/fs/xfs/xfs_iops.c
> > +++ b/fs/xfs/xfs_iops.c
> > @@ -1021,7 +1021,7 @@ xfs_vn_update_time(
> > {
> > struct xfs_inode *ip = XFS_I(inode);
> > struct xfs_mount *mp = ip->i_mount;
> > - int log_flags = XFS_ILOG_TIMESTAMP;
> > + int log_flags = XFS_ILOG_TIMESTAMP|XFS_ILOG_NOIVER;
> > struct xfs_trans *tp;
> > int error;
> >
> > @@ -1041,10 +1041,14 @@ xfs_vn_update_time(
> > return error;
> >
> > xfs_ilock(ip, XFS_ILOCK_EXCL);
> > - if (flags & S_CTIME)
> > + if (flags & S_CTIME) {
> > inode->i_ctime = *now;
> > - if (flags & S_MTIME)
> > + log_flags &= ~XFS_ILOG_NOIVER;
> > + }
> > + if (flags & S_MTIME) {
> > inode->i_mtime = *now;
> > + log_flags &= ~XFS_ILOG_NOIVER;
> > + }
> > if (flags & S_ATIME)
> > inode->i_atime = *now;
>
> I think you should also clear XFS_ILOG_NOIVER is S_VERSION is set, but
> otherwise this looks sane to me.
>
> Thanks,
> NeilBrown
Good point. I'll spin up a v2.
Thanks,
--
Jeff Layton <jlayton@xxxxxxxxxx>
