Re: linux-next: manual merge of the pidfd tree with the xfs tree

[Christian Brauner <christian.brauner@ubuntu.com>]

On Tue, Jan 26, 2021 at 07:11:15PM -0800, Darrick J. Wong wrote:
> On Wed, Jan 27, 2021 at 11:24:41AM +1100, Stephen Rothwell wrote:
> > Hi all,
> > 
> > On Mon, 25 Jan 2021 17:14:14 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> > >
> > > Today's linux-next merge of the pidfd tree got a conflict in:
> > > 
> > >   fs/xfs/xfs_inode.c
> > > 
> > > between commit:
> > > 
> > >   01ea173e103e ("xfs: fix up non-directory creation in SGID directories")
> > > 
> > > from the xfs tree and commit:
> > > 
> > >   f736d93d76d3 ("xfs: support idmapped mounts")
> > > 
> > > from the pidfd tree.
> > > 
> > > I fixed it up (see below) and can carry the fix as necessary. This
> > > is now fixed as far as linux-next is concerned, but any non trivial
> > > conflicts should be mentioned to your upstream maintainer when your tree
> > > is submitted for merging.  You may also want to consider cooperating
> > > with the maintainer of the conflicting tree to minimise any particularly
> > > complex conflicts.
> > > 
> > > diff --cc fs/xfs/xfs_inode.c
> > > index e2a1db4cee43,95b7f2ba4e06..000000000000
> > > --- a/fs/xfs/xfs_inode.c
> > > +++ b/fs/xfs/xfs_inode.c
> > > @@@ -809,13 -810,13 +810,13 @@@ xfs_init_new_inode
> > >   	inode->i_rdev = rdev;
> > >   	ip->i_d.di_projid = prid;
> > >   
> > >  -	if (pip && XFS_INHERIT_GID(pip)) {
> > >  -		inode->i_gid = VFS_I(pip)->i_gid;
> > >  -		if ((VFS_I(pip)->i_mode & S_ISGID) && S_ISDIR(mode))
> > >  -			inode->i_mode |= S_ISGID;
> > >  +	if (dir && !(dir->i_mode & S_ISGID) &&
> > >  +	    (mp->m_flags & XFS_MOUNT_GRPID)) {
> > >  +		inode->i_uid = current_fsuid();
> > 
> > Looking a bit harder, I replaced the above line with
> > 		inode->i_uid = fsuid_into_mnt(mnt_userns);
> 
> I think that looks good, though Mr. Brauner is probably better equipped
> to tell if that change is correct.

This is on top of the setgid fixup. Yes, this looks good! :)

I think what I'll do is to simply build -next for every release up until
the merge window and run the xfstests I added on the kernel. That should
reveal regressions very quickly.

> 
> (He says watching kernel.org mail take nearly a day to come through...)

Yeah, it had crazy delays (> 1 day). I chased down a few missing mails
from yesterday. Jon took that opportunity to make vger behave a little
better I believe, so delivery should be faster today, hopefully.

Christian