[lxc-devel] lxc-clone outputs some logs

[KATOH Yasufumi]

Hi,

>>> On Thu, 30 Oct 2014 14:35:16 +0000
    in message   "Re: [lxc-devel] lxc-clone outputs some logs"
                  Serge Hallyn-san wrote:

> > > > After applying commit edf7734 "overlay and aufs clone_paths: be more
> > > > robust", clone was completed successfully but lxc-clone on unpriv env
> > > > is now output the following log:
> > 
> > > >   $ lxc-clone -o ct02 -n test -s -B overlayfs
> > > >   lxc_container: conf.c: chown_mapped_root: 3649 Error stat /home/karma/.local/share/lxc/test/delta0
> > > >   Created container test as snapshot of ct02
> > > >   lxc_container: lxccontainer.c: copy_file: 2303 copy destination /home/karma/.local/share/lxc/test/lxc_rdepends exists
> > > >   Created container test as snapshot of ct02
> > 
> > > ct02 is the cloned container with overlayfs.
> > 
> > I find out other problem. After applying that patch, in part of the
> > beginning of overlayfs_clonepath function, new->dest variable is,
> > for example:
> >   "overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma/.local/share/lxc/ct02/delta0"
> > 
> > So, as the result, run "mkdir_p(new->dest, 0755)", and create dir in
> > current dir.
> > 
> > $ lxc-clone -o ct02 -n test -s -B overlayfs
> > lxc_container: conf.c: chown_mapped_root: 3649 Error stat /home/karma/.local/share/lxc/test/delta0
> > Created container test as snapshot of ct02
> > lxc_container: lxccontainer.c: copy_file: 2303 copy destination /home/karma/.local/share/lxc/test/lxc_rdepends exists
> > Created container test as snapshot of ct02
> > $ find overlayfs\:/
> > overlayfs:/
> > overlayfs:/home
> > overlayfs:/home/karma
> > overlayfs:/home/karma/.local
> > overlayfs:/home/karma/.local/share
> > overlayfs:/home/karma/.local/share/lxc
> > overlayfs:/home/karma/.local/share/lxc/ct01
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma/.local
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma/.local/share
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma/.local/share/lxc
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma/.local/share/lxc/test
> > overlayfs:/home/karma/.local/share/lxc/ct01/rootfs:/home/karma/.local/share/lxc/test/delta0

> Sorry, I'm not really following, and I guess I haven't been using overlayfs
> clones much lately.  Do you how to fix it, and can you send a patch?

This problem is also caused when clone by aufs. (between aufs/olfs)

This problem is caused by passing invalid argument as bdev *new to
(aufs|overlayfs)_clonepath.

I don't understand your patch edf7734 well. But how about revert a
part of the commit edf7734? as following:

---
 src/lxc/bdev.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/lxc/bdev.c b/src/lxc/bdev.c
index ae5c77c..a9f100c 100644
--- a/src/lxc/bdev.c
+++ b/src/lxc/bdev.c
@@ -3338,12 +3338,28 @@ struct bdev *bdev_copy(struct lxc_container *c0, const char *cname,
                return NULL;
        }
 
-       orig = bdev_init(c0->lxc_conf, src, src, NULL);
+       orig = bdev_init(c0->lxc_conf, src, NULL, NULL);
        if (!orig) {
                ERROR("failed to detect blockdev type for %s", src);
                return NULL;
        }
 
+       if (!orig->dest) {
+               int ret;
+               orig->dest = malloc(MAXPATHLEN);
+               if (!orig->dest) {
+                       ERROR("out of memory");
+                       bdev_put(orig);
+                       return NULL;
+               }
+               ret = snprintf(orig->dest, MAXPATHLEN, "%s/%s/rootfs", oldpath, oldname);
+               if (ret < 0 || ret >= MAXPATHLEN) {
+                       ERROR("rootfs path too long");
+                       bdev_put(orig);
+                       return NULL;
+               }
+       }
+
        /*
         * special case for snapshot - if caller requested maybe_snapshot and
         * keepbdevtype and backing store is directory, then proceed with a copy
-- 
2.1.1