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

[Dave Chinner <david@xxxxxxxxxxxxx>]

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@xxxxxxx>
> ---
> 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@xxxxxxxxxxxxx

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