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...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
