Re: [PATCH 25/63] xfs: return work remaining at the end of a bunmapi operation

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

On Mon, Oct 03, 2016 at 03:04:31PM -0400, Brian Foster wrote:
> On Thu, Sep 29, 2016 at 08:08:23PM -0700, Darrick J. Wong wrote:
> > Return the range of file blocks that bunmapi didn't free.  This hint
> > is used by CoW and reflink to figure out what part of an extent
> > actually got freed so that it can set up the appropriate atomic
> > remapping of just the freed range.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  fs/xfs/libxfs/xfs_bmap.c |   36 ++++++++++++++++++++++++++++++------
> >  fs/xfs/libxfs/xfs_bmap.h |    4 ++++
> >  2 files changed, 34 insertions(+), 6 deletions(-)
> > 
> > 
> > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> > index a5e429e..1e4f1a1 100644
> > --- a/fs/xfs/libxfs/xfs_bmap.c
> > +++ b/fs/xfs/libxfs/xfs_bmap.c
> ...
> > @@ -5478,6 +5481,27 @@ xfs_bunmapi(
> >  	return error;
> >  }
> >  
> > +/* Unmap a range of a file. */
> > +int
> > +xfs_bunmapi(
> > +	xfs_trans_t		*tp,
> > +	struct xfs_inode	*ip,
> > +	xfs_fileoff_t		bno,
> > +	xfs_filblks_t		len,
> > +	int			flags,
> > +	xfs_extnum_t		nexts,
> > +	xfs_fsblock_t		*firstblock,
> > +	struct xfs_defer_ops	*dfops,
> > +	int			*done)
> > +{
> > +	int			error;
> > +
> > +	error = __xfs_bunmapi(tp, ip, bno, &len, flags, nexts, firstblock,
> > +			dfops);
> > +	*done = (len == 0);
> > +	return error;
> > +}
> > +
> 
> I wonder if we really need such a wrapper for this. There aren't too
> many xfs_bunmapi() callers and at least a couple of the few that I
> checked don't even use 'done.' That can always get fixed up later
> though.

Perhaps not, but hch said he'll probably end up refactoring the bunmapi code
soon anyway.

--D

> 
> Brian
> 
> >  /*
> >   * Determine whether an extent shift can be accomplished by a merge with the
> >   * extent that precedes the target hole of the shift.
> > diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
> > index 53970b1..48ba3ed 100644
> > --- a/fs/xfs/libxfs/xfs_bmap.h
> > +++ b/fs/xfs/libxfs/xfs_bmap.h
> > @@ -197,6 +197,10 @@ int	xfs_bmapi_write(struct xfs_trans *tp, struct xfs_inode *ip,
> >  		xfs_fsblock_t *firstblock, xfs_extlen_t total,
> >  		struct xfs_bmbt_irec *mval, int *nmap,
> >  		struct xfs_defer_ops *dfops);
> > +int	__xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
> > +		xfs_fileoff_t bno, xfs_filblks_t *rlen, int flags,
> > +		xfs_extnum_t nexts, xfs_fsblock_t *firstblock,
> > +		struct xfs_defer_ops *dfops);
> >  int	xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
> >  		xfs_fileoff_t bno, xfs_filblks_t len, int flags,
> >  		xfs_extnum_t nexts, xfs_fsblock_t *firstblock,
> > 
> > --
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