[lxc-devel] [PATCH] snapshot: fix overlayfs restore
Stéphane Graber
stgraber at ubuntu.com
Tue Mar 4 22:40:01 UTC 2014
On Tue, Mar 04, 2014 at 02:54:04PM -0600, Serge Hallyn wrote:
> And add a testcase to catch regressions.
>
> Without this patch, restoring a snapshot of an overlayfs based
> container fails, because we do not pass in LXC_CLONE_SNAPSHOT,
> and overlayfs does not support clone without snapshot.
>
Acked-by: Stéphane Graber <stgraber at ubuntu.com>
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
> ---
> src/lxc/lxccontainer.c | 7 +++++--
> src/tests/snapshot.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 56 insertions(+), 4 deletions(-)
>
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index b0ae44b..877e491 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -3045,7 +3045,7 @@ out_free:
> static bool lxcapi_snapshot_restore(struct lxc_container *c, const char *snapname, const char *newname)
> {
> char clonelxcpath[MAXPATHLEN];
> - int ret;
> + int flags = 0,ret;
> struct lxc_container *snap, *rest;
> struct bdev *bdev;
> bool b = false;
> @@ -3083,7 +3083,10 @@ static bool lxcapi_snapshot_restore(struct lxc_container *c, const char *snapnam
> return false;
> }
>
> - rest = lxcapi_clone(snap, newname, c->config_path, 0, bdev->type, NULL, 0, NULL);
> + if (strcmp(bdev->type, "dir") != 0 && strcmp(bdev->type, "loop") != 0)
> + flags = LXC_CLONE_SNAPSHOT | LXC_CLONE_MAYBE_SNAPSHOT;
> + rest = lxcapi_clone(snap, newname, c->config_path, flags,
> + bdev->type, NULL, 0, NULL);
> bdev_put(bdev);
> if (rest && lxcapi_is_defined(rest))
> b = true;
> diff --git a/src/tests/snapshot.c b/src/tests/snapshot.c
> index fe06077..09cee1a 100644
> --- a/src/tests/snapshot.c
> +++ b/src/tests/snapshot.c
> @@ -26,6 +26,7 @@
> #include "lxc/lxc.h"
>
> #define MYNAME "snapxxx1"
> +#define MYNAME2 "snapxxx3"
> #define RESTNAME "snapxxx2"
>
> static void try_to_remove(void)
> @@ -45,6 +46,12 @@ static void try_to_remove(void)
> c->destroy(c);
> lxc_container_put(c);
> }
> + c = lxc_container_new(MYNAME2, NULL);
> + if (c) {
> + if (c->is_defined(c))
> + c->destroy(c);
> + lxc_container_put(c);
> + }
> c = lxc_container_new(MYNAME, NULL);
> if (c) {
> if (c->is_defined(c))
> @@ -55,7 +62,7 @@ static void try_to_remove(void)
>
> int main(int argc, char *argv[])
> {
> - struct lxc_container *c;
> + struct lxc_container *c, *c2 = NULL;
> char *template = "busybox";
>
> if (argc > 1)
> @@ -84,7 +91,7 @@ int main(int argc, char *argv[])
> c->load_config(c, NULL);
>
> if (c->snapshot(c, NULL) != 0) {
> - fprintf(stderr, "%s: %d: failed to create snapsot\n", __FILE__, __LINE__);
> + fprintf(stderr, "%s: %d: failed to create snapshot\n", __FILE__, __LINE__);
> goto err;
> }
>
> @@ -126,6 +133,48 @@ int main(int argc, char *argv[])
> goto err;
> }
>
> +
> + c2 = c->clone(c, MYNAME2, NULL, LXC_CLONE_SNAPSHOT, "overlayfs", NULL, 0, NULL);
> + if (!c2) {
> + fprintf(stderr, "%d: %s overlayfs clone failed\n", __LINE__, MYNAME2);
> + goto good;
> + }
> +
> + if (c2->snapshot(c2, NULL) != 0) {
> + fprintf(stderr, "%s: %d: failed to create snapshot\n", __FILE__, __LINE__);
> + goto err;
> + }
> +
> + n = c2->snapshot_list(c2, &s);
> + if (n < 1) {
> + fprintf(stderr, "%s: %d: failed listing containers\n", __FILE__, __LINE__);
> + goto err;
> + }
> + if (strcmp(s->name, "snap0") != 0) {
> + fprintf(stderr, "%s: %d: snapshot had bad name\n", __FILE__, __LINE__);
> + goto err;
> + }
> + for (i=0; i<n; i++) {
> + s[i].free(&s[i]);
> + }
> + free(s);
> +
> + if (!c2->snapshot_restore(c2, "snap0", NULL)) {
> + fprintf(stderr, "%s: %d: failed to restore overlayfs snapshot\n", __FILE__, __LINE__);
> + goto err;
> + }
> +
> + if (!c2->snapshot_destroy(c2, "snap0")) {
> + fprintf(stderr, "%s: %d: failed to destroy overlayfs snapshot\n", __FILE__, __LINE__);
> + goto err;
> + }
> +
> + if (!c2->destroy(c2)) {
> + fprintf(stderr, "%s: %d: failed to destroy container\n", __FILE__, __LINE__);
> + goto err;
> + }
> +
> +good:
> if (!c->destroy(c)) {
> fprintf(stderr, "%s: %d: failed to destroy container\n", __FILE__, __LINE__);
> goto err;
> --
> 1.9.0
>
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel
--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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