Re: [PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

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

On Mon, Apr 06, 2020 at 08:14:37AM -0400, Brian Foster wrote:
> On Fri, Apr 03, 2020 at 02:55:22PM +0200, Christoph Hellwig wrote:
> > Reflink should force the log out to disk if the filesystem was mounted
> > with wsync, the same as most other operations in xfs.
> > 
> 
> Isn't WSYNC for namespace operations? Why is this needed for reflink?

The manpage says that 'wsync' (the mount option) is for making namespace
operations synchronous.

However, xfs_init_fs_context sets XFS_MOUNT_WSYNC if the admin set
the 'sync' mount option, which makes all IO synchronous.

> > Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
> 
> At a glance this looks like a refactoring patch. What does this fix?

It probably ought to be 862bb360ef569f ("xfs: reflink extents from one
file to another") but so much of that was refactored for 5.0 that
backporting this fix will require changing a totally different function
(xfs_reflink_remap_range) in a totally different file (xfs_reflink.c).

--D

> Brian
> 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > ---
> >  fs/xfs/xfs_file.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > index 68e1cbb3cfcc..4b8bdecc3863 100644
> > --- a/fs/xfs/xfs_file.c
> > +++ b/fs/xfs/xfs_file.c
> > @@ -1059,7 +1059,11 @@ xfs_file_remap_range(
> >  
> >  	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
> >  			remap_flags);
> > +	if (ret)
> > +		goto out_unlock;
> >  
> > +	if (mp->m_flags & XFS_MOUNT_WSYNC)
> > +		xfs_log_force_inode(dest);
> >  out_unlock:
> >  	xfs_reflink_remap_unlock(file_in, file_out);
> >  	if (ret)
> > -- 
> > 2.25.1
> > 
>