overlayfs_mount: create delta dir if it doesn't exist

(This *should* fix the lxc-test-snapshot testcase, but doesn't seem
to by itself.)

If it doesn't exist, we may as well start with an empty one.  This
is needed when creating an overlayfs snapshot.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

diff --git a/src/lxc/bdev.c b/src/lxc/bdev.c
index 64e88322a9bc5580ca056f6640babc777fa95e22..b81827eaedb26c9090dbd3b5c72e524a5666e8a4 100644 (file)
--- a/src/lxc/bdev.c
+++ b/src/lxc/bdev.c
@@ -2224,6 +2224,10 @@ static int overlayfs_mount(struct bdev *bdev)
        *upper = '\0';
        upper++;
 
+       // if delta doesn't yet exist, create it
+       if (mkdir_p(upper, 0755) < 0 && errno != EEXIST)
+               return -22;
+
        // overlayfs.v22 or higher needs workdir option
        // if upper is /var/lib/lxc/c2/delta0,
        // then workdir is /var/lib/lxc/c2/olwork