Re: [PATCH 1/3] xfsprog: add xfs sb v4 support for dirent filetype field

Dave Chinner
2013-09-19T22:52:55Z

On Thu, Sep 19, 2013 at 04:05:24PM -0500, Mark Tinguely wrote:
> Add xfsprog superblock v4 support for the directory inode type
> in xfs_sb.h.
>
> This support adds a feature bit for version 4 superblocks and
> leaves the original superblock 5 incompatibility bit.
>
> Signed-off-by: Mark Tinguely <tinguely@sgi.com>
> ---
> include/xfs_sb.h | 20 ++++++++++++--------
> include/xfs_sb.h | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> Index: b/include/xfs_sb.h
> ===================================================================
> --- a/include/xfs_sb.h
> +++ b/include/xfs_sb.h
> @@ -84,11 +84,13 @@ struct xfs_trans;
> #define XFS_SB_VERSION2_PARENTBIT 0x00000010 /* parent pointers */
> #define XFS_SB_VERSION2_PROJID32BIT 0x00000080 /* 32 bit project id */
> #define XFS_SB_VERSION2_CRCBIT 0x00000100 /* metadata CRCs */
> +#define XFS_SB_VERSION2_FTYPE 0x00000200 /* inode type in dir */
>
> #define XFS_SB_VERSION2_OKREALFBITS \
> (XFS_SB_VERSION2_LAZYSBCOUNTBIT | \
> XFS_SB_VERSION2_ATTR2BIT | \
> - XFS_SB_VERSION2_PROJID32BIT)
> + XFS_SB_VERSION2_PROJID32BIT | \
> + XFS_SB_VERSION2_FTYPE)
> #define XFS_SB_VERSION2_OKSASHFBITS \
> (0)
> #define XFS_SB_VERSION2_OKREALBITS \
> @@ -631,8 +633,10 @@ static inline int xfs_sb_version_has_pqu
>
> static inline int xfs_sb_version_hasftype(struct xfs_sb *sbp)
> {
> - return XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
> - xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_FTYPE);
> + return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
> + xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_FTYPE)) ||
> + (xfs_sb_version_hasmorebits(sbp) &&
> + (sbp->sb_features2 & XFS_SB_VERSION2_FTYPE));

This is kinda inefficient. Seeing as I didn't review the kernel
version, I'll review it now. Expand it out:

return (XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5 &&
xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_FTYPE)) ||
((XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_5) ||
(XFS_SB_VERSION_NUM(sbp) == XFS_SB_VERSION_4 &&
(sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT))) &&
(sbp->sb_features2 & XFS_SB_VERSION2_FTYPE));

so, really, the check could be refined to:

return XFS_SB_VERSION_NUM(sbp) >= XFS_SB_VERSION_4 &&
(xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_FTYPE) ||
((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) &&
(sbp->sb_features2 & XFS_SB_VERSION2_FTYPE)));

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com