Re: "Failed to preserve ownership" exit(1) bug in mv?

[Jim Minter]

On 03/06/17 05:56, Pádraig Brady wrote:
> On 02/06/17 09:07, Jim Minter wrote:
> > Hello,
> >
> > A behaviour that surprised me with mv, moving files to an NFS-mounted
> > filesystem with all_squash set (in a Vagrant box running Fedora 25,
> > coreutils 8.25).
> >
> > (/vagrant is NFS-mounted as described in the example below).
> >
> > ==== 8< ====
> > [vagrant@default ~]$ sudo -i
> > [root@default ~]# ln -s thing symlink
> > [root@default /]# mv symlink /vagrant
> > mv: failed to preserve ownership for /vagrant/symlink: Operation not
> > permitted
> > [root@default /]# echo $?
> > 1
> > [root@default /]# ls . /vagrant
> > .:
> > symlink
> >
> > /vagrant:
> > symlink
> > ==== 8< ====
> >
> > The surprise to me is that mv exits early in this case (after copying
> > the symlink across volumes, before removing the source symlink).
> >
> > Doing the same operation as root but with a regular file, I get the same
> > warning message, but the move completes as expected, and mv returns exit
> > status 0.  I had expected the same behaviour when moving a symlink.
> >
> > (As non-root, mv works as expected both for a file and for a symlink -
> > object moved, chown syscall fails, no warning message).
> >
> > The knock-on effect I've seen which is particularly problematic, is that
> > this issue causes mv to fail when moving an entire directory tree as
> > root to an NFS-mounted filesystem, if that directory tree contains a
> > symlink anywhere within it.  Can the exit(1) in this case be considered
> > a bug?
>
> That indeed looks like a bug that has been present since the initial 
> implementation!
> The attached should fix it up.
>
> thanks!
> Pádraig

Hi Pádraig,

Many thanks for the quick reply.  I've checked and confirm that your 
patch resolves the problem for me.

Cheers,

Jim