The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/bc7301a2fdd495c9b59699f425e99655fde4c822

commit bc7301a2fdd495c9b59699f425e99655fde4c822
Author: Allen Webb <allenwebb@google.com>
Date: Tue Dec 04 08:11:39 2018

biod: add MS_REC to daemon-store bind mount.

This fixes a potential issue where if biod crashes after a user signs in
biod will not be able to access the user specific data.

BUG= chromium:910775 
TEST=Restart biod after signing in and verify fingerprint auth works.

Change-Id: I5a21e649529330ad6bce1306f7df6892d6a4cd4b
Reviewed-on: https://chromium-review.googlesource.com/1357317
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Allen Webb <allenwebb@google.com>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Nicolas Norvez <norvez@chromium.org>

[modify] https://crrev.com/bc7301a2fdd495c9b59699f425e99655fde4c822/biod/init/biod.conf

I think this may still be broken due to biod's SetDiskAccesses() control, which prevents reading templates from storage unless set.

Repro case:
1) Log in
2) Add fingerprint
3) restart biod: initctl restart biod
4) Lock device
5) Unlocking with fingerprint fails

biod logs (/var/log/biod/biod.LATEST) show:

[1206/153955.661999:INFO:biometrics_daemon.cc(482)] Primary user updated to 0227a7d5fb677150af3d793c079fcb8c87d2e510.
[1206/153955.666021:ERROR:biod_storage.cc(114)] Access to the storage mounts not yet allowed.

If I modify biod to SetDiskAccess(true) after retrieving the primary user session, the templates appear to load:

[1206/153611.457061:INFO:biometrics_daemon.cc(482)] Primary user updated to 0227a7d5fb677150af3d793c079fcb8c87d2e510.
[1206/153611.462325:INFO:cros_fp_biometrics_manager.cc(623)] Upload record ad022114_2efc_48a7_9745_6a8a9a1d7789

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/aba492a46e047201da225e7489cbed2450539f70

commit aba492a46e047201da225e7489cbed2450539f70
Author: Allen Webb <allenwebb@google.com>
Date: Sat Dec 08 02:14:26 2018

biod: add MS_REC to daemon-store bind mount.

This fixes a potential issue where if biod crashes after a user signs in
biod will not be able to access the user specific data.

BUG= chromium:910775 
TEST=Restart biod after signing in and verify fingerprint auth works.

Change-Id: I5a21e649529330ad6bce1306f7df6892d6a4cd4b
Reviewed-on: https://chromium-review.googlesource.com/1357317
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Allen Webb <allenwebb@google.com>
Reviewed-by: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Nicolas Norvez <norvez@chromium.org>
(cherry picked from commit bc7301a2fdd495c9b59699f425e99655fde4c822)
Reviewed-on: https://chromium-review.googlesource.com/c/1363539
Reviewed-by: YH Lin <yueherngl@chromium.org>
Commit-Queue: YH Lin <yueherngl@chromium.org>
Tested-by: YH Lin <yueherngl@chromium.org>

[modify] https://crrev.com/aba492a46e047201da225e7489cbed2450539f70/biod/init/biod.conf