Re: [PATCH 1/3] xfs: add a xfs_valid_startblock helper

[Christoph Hellwig <hch@lst.de>]

On Fri, Aug 30, 2019 at 08:06:50AM -0700, Darrick J. Wong wrote:
> > --- a/fs/xfs/libxfs/xfs_bmap.h
> > +++ b/fs/xfs/libxfs/xfs_bmap.h
> > @@ -171,6 +171,9 @@ static inline bool xfs_bmap_is_real_extent(struct xfs_bmbt_irec *irec)
> >  		!isnullstartblock(irec->br_startblock);
> >  }
> >  
> > +#define xfs_valid_startblock(ip, startblock) \
> > +	((startblock) != 0 || XFS_IS_REALTIME_INODE(ip))
> 
> We have more robust validators for data/rtdev fsblock_t, so why not:
> 
> #define xfs_valid_startblock(ip, startblock) \
> 	(XFS_IS_REALTIME_INODE(ip) ? xfs_verify_rtbno(startblock) : \
> 				     xfs_verify_fsbno(startblock))
> 
> and why not make it a static inline function too?

I tried an inline function, but I could not find a header to place
it that would actually easily compile everywhere...  Maybe we should
just make that a xfs_verify_bno(mp, startblock) and move that out of
line such in a way that a smart compiler avoids the function call
overhead for xfs_verify_rtbno / xfs_verify_fsbno.  I'll take another
stab at this.