On Fri, Sep 29, 2017 at 11:22 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > Enforcing exclusive ownership on upper/work dirs caused a docker > regression: https://github.com/moby/moby/issues/34672. > > Euan spotted the regression and pointed to the offending commit. > Vivek has brought the regression to my attention and provided this > reproducer: > > Terminal 1: > > mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none > merged/ > > Terminal 2: > > unshare -m > > Terminal 1: > > umount merged > mount -t overlay -o workdir=work,lowerdir=lower,upperdir=upper none > merged/ > mount: /root/overlay-testing/merged: none already mounted or mount point > busy > > To fix the regression, I replaced the error with an alarming warning. > With index feature enabled, mount does fail, but logs a suggestion to > override exclusive dir protection by disabling index. > Note that index=off mount does take the inuse locks, so a concurrent > index=off will issue the warning and a concurrent index=on mount will fail. > > Documentation was updated to reflect this change. > > Fixes: 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs") > Cc: <stable@xxxxxxxxxxxxxxx> # v4.13 > Reported-by: Euan Kemp <euank@xxxxxxxxx> > Reported-by: Vivek Goyal <vgoyal@xxxxxxxxxx> Euan, Vivek Apparently, git send-email doesn't pick up the Reported-by tags, so did not CC you. Care to test this patch? I am going to update xfstest overlay/036 to reflect this change: https://github.com/amir73il/xfstests/commit/c8098b949a0f3338e6f45e94e28ee6b7baa284e7 Vivek, Do you mind making your reproducer into an xfstest? If you do, please note that there is currently no _require_namespace in xfstests and the only test that does use unshare (overlay/020) just fails when kernel has no namespaces support, so this will have to be fixed. Thanks! Amir. -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
