[PATCH 2/4] xfs: dirent dtype presence is dependent on directory magic numbers

[Ben Myers]

On Mon, Sep 30, 2013 at 09:37:04AM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner at redhat.com>
> 
> The determination of whether a directory entry contains a dtype
> field originally was dependent on the filesystem having CRCs
> enabled. This meant that the format for dtype beign enabled could be
> determined by checking the directory block magic number rather than
> doing a feature bit check. This was useful in that it meant that we
> didn't need to pass a struct xfs_mount around to functions that
> were already supplied with a directory block header.
> 
> Unfortunately, the introduction of dtype fields into the v4
> structure via a feature bit meant this "use the directory block
> magic number" method of discriminating the dirent entry sizes is
> broken. Hence we need to convert the places that use magic number
> checks to use feature bit checks so that they work correctly and not
> by chance.
> 
> The current code works on v4 filesystems only because the dirent
> size roundup covers the extra byte needed by the dtype field in the
> places where this problem occurs.
> 
> Signed-off-by: Dave Chinner <dchinner at redhat.com>

Looks fine to me.

Reviewed-by: Ben Myers <bpm at sgi.com>