On Sun, Sep 01, 2019 at 09:36:34AM +0200, Christoph Hellwig wrote: > On Fri, Aug 30, 2019 at 05:32:53PM +0200, Christoph Hellwig wrote: > > 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. > > So I looked into your suggestion, but xfs_verify_rtbno / xfs_verify_fsbno > do a lot of validity checking, but they don't actually contain the > check that was in the existing code. The bmap code just checks that > there is a startblock of 0 for non-rt devices, probably this was added > to find some old bug where a irec structure that was zeroed was returned. > > So replacing it with xfs_verify_rtbno / xfs_verify_fsbno would not help > in any way. But the big question is if keeping the 0 check is even > worth it. It's been mildly helpful for noticing when my online/offline repair prototype code totally screws up, but at that point so much magic smoke is already pouring out everywhere that it's hard not to notice. :) --D
