Re: [PATCH 07/11] xfs: refactor eofb matching into a single helper

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

On Wed, May 20, 2020 at 08:42:11AM +0200, Christoph Hellwig wrote:
> On Tue, May 19, 2020 at 06:46:02PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Refactor the two eofb-matching logics into a single helper so that we
> > don't repeat ourselves.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  fs/xfs/xfs_icache.c |   59 +++++++++++++++++++++++++++------------------------
> >  1 file changed, 31 insertions(+), 28 deletions(-)
> > 
> > 
> > diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> > index ac66e7d8698d..1f12c6a0c48e 100644
> > --- a/fs/xfs/xfs_icache.c
> > +++ b/fs/xfs/xfs_icache.c
> > @@ -1436,6 +1436,33 @@ xfs_inode_match_id_union(
> >  	return 0;
> >  }
> >  
> > +/*
> > + * Is this inode @ip eligible for eof/cow block reclamation, given some
> > + * filtering parameters @eofb?  The inode is eligible if @eofb is null or
> > + * if the predicate functions match.
> > + */
> > +static bool
> > +xfs_inode_matches_eofb(
> > +	struct xfs_inode	*ip,
> > +	struct xfs_eofblocks	*eofb)
> > +{
> > +	int			match;
> > +
> > +	if (!eofb)
> > +		return true;
> > +
> > +	if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
> > +		match = xfs_inode_match_id_union(ip, eofb);
> > +	else
> > +		match = xfs_inode_match_id(ip, eofb);
> > +	if (match)
> > +		return true;
> > +
> > +	/* skip the inode if the file size is too small */
> > +	return !(eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE &&
> > +		 XFS_ISIZE(ip) < eofb->eof_min_file_size);
> 
> This looks wrong - the size check should be applied if we did already
> find a match and not override it based on the current code, e.g.:
> 
> 	if (eofb->eof_flags & XFS_EOF_FLAGS_UNION)
> 		match = xfs_inode_match_id_union(ip, eofb);
> 	else
> 		match = xfs_inode_match_id(ip, eofb);
> 
> 	if (match) {
> 		/* skip the inode if the file size is too small */
> 		if ((eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE) &&
> 		    XFS_ISIZE(ip) < eofb->eof_min_file_size)
> 			return false;
> 	}
> 
> 	return match;

Ah, I see what I did wrong here; the size check was another opportunity
for us to say no even if the inode matched.  Ok, I'll go fix it.

--D