On Thu, Jun 07, 2018 at 07:42:05AM -0400, Brian Foster wrote:
> On Thu, Jun 07, 2018 at 03:27:50PM +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@xxxxxxxxxx>
> >
> > do_mod() is a hold-over from when we have different sizes for file
> > offsets and and other internal values for 40 bit XFS filesystems.
> > Hence depending on build flags variables passed to do_mod() could
> > change size. We no longer support those small format filesystems and
> > hence everything is of fixed size theses days, even on 32 bit
> > platforms.
> >
> > As such, we can convert all the do_mod() callers to platform
> > optimised modulus operations as defined by linux/math64.h.
> > Individual conversions depend on the types of variables being used.
> >
> > Signed-Off-By: Dave Chinner <dchinner@xxxxxxxxxx>
> > ---
> > fs/xfs/libxfs/xfs_bmap.c | 37 +++++++++++++++++++++++--------------
> > fs/xfs/xfs_bmap_util.c | 14 +++++++++-----
> > fs/xfs/xfs_inode.c | 2 +-
> > fs/xfs/xfs_iomap.h | 4 ++--
> > fs/xfs/xfs_linux.h | 19 -------------------
> > fs/xfs/xfs_log_recover.c | 32 +++++++++++++++++++++++++-------
> > fs/xfs/xfs_rtalloc.c | 15 +++++++++++----
> > 7 files changed, 71 insertions(+), 52 deletions(-)
> >
> ...
> > diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
> > index 7d897c58b0c8..4405ff21f9a9 100644
> > --- a/fs/xfs/xfs_log_recover.c
> > +++ b/fs/xfs/xfs_log_recover.c
> > @@ -1235,6 +1235,25 @@ xlog_verify_head(
> > be32_to_cpu((*rhead)->h_size));
> > }
> >
> > +/*
> > + * We need to make sure we handle log wrapping properly, so we can't use teh
> > + * calculated logbno directly. Make sure it wraps to teh correct bno inside teh
> > + * log.
> > + *
>
> s/teh/the/
>
> > + * The log is limited to 32 bit sizes, so we use the appropriate modulus
> > + * operation here and cast it back to a 64 bit daddr on return.
> > + */
> > +static inline xfs_daddr_t
> > +xlog_wrap_logbno(
> > + struct xlog *log,
> > + xfs_daddr_t bno)
> > +{
> > + int mod;
> > +
> > + div_s64_rem(bno, log->l_logBBsize, &mod);
> > + return mod;
> > +}
> > +
> > /*
> > * Check whether the head of the log points to an unmount record. In other
> > * words, determine whether the log is clean. If so, update the in-core state
> ...
> > diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
> > index 80bbfe604ce0..776502a5dcb7 100644
> > --- a/fs/xfs/xfs_rtalloc.c
> > +++ b/fs/xfs/xfs_rtalloc.c
> ...
> > @@ -1262,8 +1266,11 @@ xfs_rtpick_extent(
> > resid = seq - (1ULL << log2);
> > b = (mp->m_sb.sb_rextents * ((resid << 1) + 1ULL)) >>
> > (log2 + 1);
> > - if (b >= mp->m_sb.sb_rextents)
> > - b = do_mod(b, mp->m_sb.sb_rextents);
> > + if (b >= mp->m_sb.sb_rextents) {
> > + xfs_rtblock_t mod;
> > + div64_u64_rem(b, mp->m_sb.sb_rextents, &mod);
> > + b = mod;
> > + }
>
> Shouldn't we be able to do 'div64_u64_rem(b, mp->m_sb.sb_rextents, &b)'
> here? Otherwise looks fine:
I think Dave is trying to avoid aliasing the arguments in case
div64_u64_rem ever gets turned into a horrible macro (or over-optimized
by gcc)
--D
>
> Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
>
> > if (b + len > mp->m_sb.sb_rextents)
> > b = mp->m_sb.sb_rextents - len;
> > }
> > --
> > 2.17.0
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
