tree ab603f3e1e05e398a9460f672e95930db4bce953
parent 3526f6d330874b1e3f955c71af3ea6e84421fc07
author Joel Hockey <joelhockey@chromium.org> 1543968999 -0800
committer Commit Bot <commit-bot@chromium.org> 1596846395 +0000

vm_tools: seneschal: Force unmount MNT_DETACH for MyFiles if EBUSY

MyFiles has Downloads bind-mounted within it.  When MyFiles is shared
and mounted, the Downloads mount propagates.

When we unshare MyFiles, we first try to unmount MyFiles/Downloads, but
it fails with EINVAL.  If we then continue and unmount MyFiles, it fails
with EBUSY regardless of whether any files are open.

This fixes by ignoring the first error for MyFiles/Downloads, and then
reattempting to unmount with MNT_DETACH set if unmounting MyFiles fails
with EBUSY.

BUG=chromium:1112190
TEST=share then unshare MyFiles root

Change-Id: Ib3995d8f867928c451eab3ff987b391cce795f84
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/1404454
Tested-by: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>