[lxc-devel] [PATCH] c/r: force users to provide a fresh directory for criu images
Tycho Andersen
tycho.andersen at canonical.com
Wed Apr 22 19:27:04 UTC 2015
On Wed, Apr 22, 2015 at 01:16:08PM -0600, Tycho Andersen wrote:
> CRIU can get confused if more than one c/r is done in the same directory, so we
> should require lxcapi so that it refuses to dump to a directory with criu
> images already in it.
Hmm, actually I'm not sure this is the best way to do this. If users
(e.g. LXD) use some sort of mechanism to generate a temporary
directory name we could race if the same name is tried twice in a row.
Instead, maybe it's just best to stat() for the key criu image file
(inventory.img), and die if it's there.
Thoughts?
> This won't help if the user copies a checkpoint over another, but at least the
> common case will be caught.
>
> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
> ---
> src/lxc/lxccontainer.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index dbcee99..4a290f1 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -3687,8 +3687,13 @@ static bool do_lxcapi_checkpoint(struct lxc_container *c, char *directory, bool
> if (!criu_ok(c))
> return false;
>
> - if (mkdir(directory, 0700) < 0 && errno != EEXIST)
> + if (mkdir(directory, 0700) < 0) {
> + if (errno == EEXIST)
> + ERROR("please use a new directory for criu state");
> + else
> + SYSERROR("mkdir failed");
> return false;
> + }
>
> if (!dump_net_info(c, directory))
> return false;
> --
> 2.1.4
>
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