From 39460be89e946c9fbce3c4553b1d9d24d310365d Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 5 Apr 2016 19:23:12 +0200 Subject: [PATCH] set lxc.rootfs.backend on container creation Since specifying lxc.rootfs.backend can lead to performance improvements we always set it during container creation. This also fixes a bug. do_bdev_create() tried to be smart and retrieve the lower directory when bdev->type == overlayfs or aufs thereby cutting the path. However, this operation is done in ovl_mount() and aufs_mount() and both functions need the full src path for this. The bug didn't show before because when creating a overlayfs container with e.g.: lxc-create -n c -t busybox -B overlayfs still left bdev->type set to dir and so the code for retrieving the lower dir in do_bdev_create() was skipped. But by setting lxc.rootfs.backend on container creation we force bdev->type to be set to e.g. overlayfs and the code gets executed thereby exposing the bug. Signed-off-by: Christian Brauner --- src/lxc/lxccontainer.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c index 5c6d49933..29cbd330c 100644 --- a/src/lxc/lxccontainer.c +++ b/src/lxc/lxccontainer.c @@ -1037,6 +1037,7 @@ static struct bdev *do_bdev_create(struct lxc_container *c, const char *type, } do_lxcapi_set_config_item(c, "lxc.rootfs", bdev->src); + do_lxcapi_set_config_item(c, "lxc.rootfs.backend", bdev->type); /* if we are not root, chown the rootfs dir to root in the * target uidmap */ @@ -1076,7 +1077,7 @@ static bool create_run_template(struct lxc_container *c, char *tpath, bool need_ } if (pid == 0) { // child - char *patharg, *namearg, *rootfsarg, *src; + char *patharg, *namearg, *rootfsarg; struct bdev *bdev = NULL; int i; int ret, len, nargs = 0; @@ -1087,18 +1088,7 @@ static bool create_run_template(struct lxc_container *c, char *tpath, bool need_ exit(1); } - src = c->lxc_conf->rootfs.path; - /* - * for an overlay create, what the user wants is the template to fill - * in what will become the readonly lower layer. So don't mount for - * the template - */ - if (strncmp(src, "overlayfs:", 10) == 0) - src = ovl_getlower(src+10); - if (strncmp(src, "aufs:", 5) == 0) - src = ovl_getlower(src+5); - - bdev = bdev_init(c->lxc_conf, src, c->lxc_conf->rootfs.mount, NULL); + bdev = bdev_init(c->lxc_conf, c->lxc_conf->rootfs.path, c->lxc_conf->rootfs.mount, NULL); if (!bdev) { ERROR("Error opening rootfs"); exit(1);