On Thu, Jul 15, 2021 at 09:35:54AM +1000, Dave Chinner wrote:
> On Wed, Jul 14, 2021 at 04:15:49PM -0700, Darrick J. Wong wrote:
> > On Wed, Jul 14, 2021 at 02:19:06PM +1000, Dave Chinner wrote:
> > > From: Dave Chinner <dchinner@xxxxxxxxxx>
> > >
> > > Reporting filesystem features to userspace is currently superblock
> > > based. Now we have a general mount-based feature infrastructure,
> > > switch to using the xfs_mount rather than the superblock directly.
> > >
> > > This reduces the size of the function by over 300 bytes.
> > >
> > > $ size -t fs/xfs/built-in.a
> > > text data bss dec hex filename
> > > before 1127855 311352 484 1439691 15f7cb (TOTALS)
> > > after 1127535 311352 484 1439371 15f68b (TOTALS)
> > >
> > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> > > ---
> > > fs/xfs/libxfs/xfs_sb.c | 46 ++++++++++++++++++++++--------------------
> > > fs/xfs/libxfs/xfs_sb.h | 2 +-
> > > fs/xfs/xfs_ioctl.c | 2 +-
> > > fs/xfs/xfs_ioctl32.c | 2 +-
> > > 4 files changed, 27 insertions(+), 25 deletions(-)
> > >
> > > diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> > > index baaec7e6a975..5eaf14b6fe3c 100644
> > > --- a/fs/xfs/libxfs/xfs_sb.c
> > > +++ b/fs/xfs/libxfs/xfs_sb.c
> > > @@ -1016,10 +1016,12 @@ xfs_sync_sb_buf(
> > >
> > > void
> > > xfs_fs_geometry(
> > > - struct xfs_sb *sbp,
> > > + struct xfs_mount *mp,
> >
> > Hmm. I /think/ this won't cause problems in userspace, because db
> > passes in &mp->m_sb, and mkfs passes in sbp, which points to &mp->m_sb,
> > and mp itself points to &mbuf...
>
> Yes, AFAICT that is correct. mkfs.xfs has the same setup so it
> should work there, too.
>
> > > struct xfs_fsop_geom *geo,
> > > int struct_version)
> > > {
> > > + struct xfs_sb *sbp = &mp->m_sb;
> > > +
> > > memset(geo, 0, sizeof(struct xfs_fsop_geom));
> > >
> > > geo->blocksize = sbp->sb_blocksize;
> > > @@ -1050,51 +1052,51 @@ xfs_fs_geometry(
> > > geo->flags = XFS_FSOP_GEOM_FLAGS_NLINK |
> > > XFS_FSOP_GEOM_FLAGS_DIRV2 |
> > > XFS_FSOP_GEOM_FLAGS_EXTFLG;
> > > - if (xfs_sb_version_hasattr(sbp))
> > > + if (xfs_has_attr(mp))
> >
> > ...provided those utilities set m_features before we get to this point,
> > right? And provided that libxfs_init will take care of that, I think
> > only mkfs would need special consideration, right?
>
> Yup, that's how I read the usrespace situation - the superblock we
> pass to xfs_fs_geometry() is always attached to a mount structure,
> and we'll set up the features field in the mount when we first read
> in the superblock in libxfs_init(). mkfs might require a specific
> call to set up the m_features field after the superblock is
> finalised (i.e in initialise_mount()), but other than that I
> think it all just works...
Ok. I'm glad you thought about userspace too!
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx
