Re: [PATCH 07/21] xfs: add scrub cross-referencing helpers for the inode btrees

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Jan 05, 2018 at 12:36:06PM +1100, Dave Chinner wrote:
> On Fri, Dec 22, 2017 at 04:43:35PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Add a couple of functions to the inode btrees that will be used
> > to cross-reference metadata against the inobt.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  fs/xfs/libxfs/xfs_ialloc.c |   99 ++++++++++++++++++++++++++++++++++++++++++++
> >  fs/xfs/libxfs/xfs_ialloc.h |    6 +++
> >  2 files changed, 105 insertions(+)
> 
> Some minor things.
> 
> > diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> > index 3b57ef0..5de1ef3 100644
> > --- a/fs/xfs/libxfs/xfs_ialloc.c
> > +++ b/fs/xfs/libxfs/xfs_ialloc.c
> > @@ -2751,3 +2751,102 @@ xfs_verify_dir_ino(
> >  		return false;
> >  	return xfs_verify_ino(mp, ino);
> >  }
> > +
> > +/* Is there an inode record covering a given range of inode numbers? */
> > +int
> > +xfs_ialloc_has_inode_record(
> > +	struct xfs_btree_cur	*cur,
> > +	xfs_agino_t		low,
> > +	xfs_agino_t		high,
> > +	bool			*exists)
> > +{
> > +	struct xfs_inobt_rec_incore	irec;
> > +	xfs_agino_t		agino;
> > +	uint16_t		holemask;
> > +	int			has;
> 
> has_record

Fixed.

> > +	int			i;
> > +	int			error;
> > +
> > +	*exists = false;
> > +	error = xfs_inobt_lookup(cur, low, XFS_LOOKUP_LE, &has);
> > +	while (error == 0 && has) {
> > +		error = xfs_inobt_get_rec(cur, &irec, &has);
> > +		if (error || irec.ir_startino > high)
> > +			break;
> > +
> > +		agino = irec.ir_startino;
> > +		holemask = irec.ir_holemask;
> > +		for (i = 0; i < XFS_INOBT_HOLEMASK_BITS; holemask >>= 1,
> > +				i++, agino += XFS_INODES_PER_HOLEMASK_BIT) {
> > +			if (holemask & 1)
> > +				continue;
> > +			if (agino + XFS_INODES_PER_HOLEMASK_BIT > low &&
> > +					agino <= high) {
> > +				*exists = true;
> > +				goto out;
> 
> return 0;
> 
> Then the out label can go away.

Fixed.

> > +			}
> > +		}
> > +
> > +		error = xfs_btree_increment(cur, 0, &has);
> > +	}
> > +out:
> > +	return error;
> > +}
> > +
> > +/* Is there an inode record covering a given extent? */
> > +int
> > +xfs_ialloc_has_inodes_at_extent(
> > +	struct xfs_btree_cur	*cur,
> > +	xfs_agblock_t		bno,
> > +	xfs_extlen_t		len,
> > +	bool			*exists)
> > +{
> > +	xfs_agino_t		low;
> > +	xfs_agino_t		high;
> > +
> > +	low = XFS_OFFBNO_TO_AGINO(cur->bc_mp, bno, 0);
> > +	high = XFS_OFFBNO_TO_AGINO(cur->bc_mp, bno + len, 0) - 1;
> > +
> > +	return xfs_ialloc_has_inode_record(cur, low, high, exists);
> > +}
> > +
> > +struct xfs_ialloc_count_inodes {
> > +	xfs_agino_t			count;
> > +	xfs_agino_t			freecount;
> > +};
> > +
> > +/* Record inode counts across all inobt records. */
> > +STATIC int
> > +xfs_ialloc_count_inodes_helper(
> > +	struct xfs_btree_cur		*cur,
> > +	union xfs_btree_rec		*rec,
> > +	void				*priv)
> > +{
> > +	struct xfs_inobt_rec_incore	irec;
> > +	struct xfs_ialloc_count_inodes	*ci = priv;
> > +
> > +	xfs_inobt_btrec_to_irec(cur->bc_mp, rec, &irec);
> > +	ci->count += irec.ir_count;
> > +	ci->freecount += irec.ir_freecount;
> > +
> > +	return 0;
> > +}
> > +
> > +/* Count allocated and free inodes under an inobt. */
> > +int
> > +xfs_ialloc_count_inodes(
> > +	struct xfs_btree_cur		*cur,
> > +	xfs_agino_t			*count,
> > +	xfs_agino_t			*freecount)
> > +{
> > +	struct xfs_ialloc_count_inodes	ci = {0};
> > +	int				error;
> > +
> > +	ASSERT(cur->bc_btnum == XFS_BTNUM_INO);
> > +	error = xfs_btree_query_all(cur, xfs_ialloc_count_inodes_helper, &ci);
> > +	if (!error) {
> > +		*count = ci.count;
> > +		*freecount = ci.freecount;
> > +	}
> > +	return error;
> 
> Took me a minute to release that the branch was run when !error.
> I'd be more obvious if it used typical error handling:
> 
> 	if (error)
> 		return error;
> 	*count = ci.count;
> 	*freecount = ci.freecount;
> 	return 0;

Fixed.

--D

> Cheers,
> 
> Dave.
> 
> -- 
> Dave Chinner
> david@fromorbit.com
> --
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