Attached is a copy of the 99-btrfs.rules file that I created, as
discussed in this bug
The version of the package released in wheezy was 0.19+20120328-7.1 -
without the bug fix
The bug fix installs the file as /lib/udev/rules.d/80-btrfs-lvm.rules -
not the same filename that was discussed in this bug report
This was included in version 3.17-1.1 in jessie
Anybody who created the file manually may have had two copies of it on
their system after upgrading to jessie
Running jessie, I observed intermittent problems with non-Btrfs
filesystems failing to mount on every boot on the system where this udev
file was created manually[1]
In some later version of the btrfs-tools package (or its successor,
btrfs-progs), the udev files were removed from the package (see
debian/changelog). After upgrading to one of these newer versions of
the package, either from jessie-backports or stretch, the manually
created 99-btrfs.rules file was left on the system even after the
80-btrfs-lvm.rules was removed by the package upgrade.
The existence of this file as a potential source of the mount problem
only became apparent after upgrading the system to stretch. Running
stretch, the journalctl logs appear to be more verbose than jessie and
they show the 'btrfs scan' commands between attempted and failing around
the same time that the ext4 mounts are attempted and failing with EBUSY.
1. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=829180
SUBSYSTEM!="block", GOTO="btrfs_lvm_end"
ENV{DM_UUID}!="LVM-?*", GOTO="btrfs_lvm_end"
RUN+="/sbin/modprobe btrfs"
RUN+="/sbin/btrfs device scan $env{DEVNAME}"
LABEL="btrfs_lvm_end"
