Bug#950266: Each caja time started, mounts multiple extra copies of btrfs filesystem

[Anthony DeRobertis <anthony@derobert.net>]

Package: caja
Version: 1.22.3-1
Severity: important

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I have a 4-disk btrfs filesystem, which is stored on encrypted disks
(LUKS) if it matters. Before starting Caja, the disks have been unlocked
and the filesystem mounted (both done with udisksctl).

Caja does two weird things with this filesystem, one cosmetic and one a
problem:

1. It shows 4 (or more) times in the "Places" pane, initially one as
   mounted and 3 as not mounted. This would just be cosmetic, except...

2. Each time caja is mounted, it seems to ask udisks to mount the other
   three copies it sees. So each caja start results in another three
   mounts of the filesystem, and since I only have it running when
   needed... very quickly I get dozens of them. This makes all kinds of
   things slow — e.g., bringing up a "Save" dialog in many apps pegs the
   CPU for seconds, hanging the app until its done.

I tried turning on "Never prompt or start programs on media insertion"
and turning off "Browse media when inserted" in hopes that'd work around
the issue, but it doesn't. Caja still mounts three more copies each
start.

I'm pretty sure its asking udisks to do the mount because of systemd
journal entries which appear when caja starts:

Jan 30 13:45:11 Watt systemd[1]: Started Clean the /media/anthony/BigBackup18 mount point.
Jan 30 13:45:11 Watt systemd[1]: Started Clean the /media/anthony/BigBackup16 mount point.
Jan 30 13:45:11 Watt systemd[1]: Started Clean the /media/anthony/BigBackup17 mount point.
Jan 30 13:45:11 Watt udisksd[1154]: Mounted /dev/dm-15 at /media/anthony/BigBackup18 on behalf of uid 1000
Jan 30 13:45:11 Watt udisksd[1154]: Mounted /dev/dm-18 at /media/anthony/BigBackup16 on behalf of uid 1000
Jan 30 13:45:11 Watt udisksd[1154]: Mounted /dev/dm-17 at /media/anthony/BigBackup17 on behalf of uid 1000

I eventually worked around this issue by setting up a systemd timer to
unmount the extra ones every 10 minutes ☹

- --- /etc/systemd/system/local-umount-BBU-clones.service ---
[Unit]
ConditionPathExistsGlob=/media/anthony/BigBackup[0-9]*

[Service]
Type=oneshot
ExecStart=sh -c 'for m in /media/anthony/BigBackup[0-9]*; do umount "$m"; done'

- --- /etc/systemd/system/local-umount-BBU-clones.timer ---
[Unit]
Description=Kluge around udisks/caja mounting extra copies of BigBackup

[Install]
WantedBy=timers.target

[Timer]
OnBootSec=10m
OnUnitActiveSec=10m
RandomizedDelaySec=1m


- -- System Information:
Debian Release: bullseye/sid
  APT prefers testing-debug
  APT policy: (500, 'testing-debug'), (500, 'stable-updates'), (500, 'testing'), (500, 'stable'), (130, 'unstable-debug'), (130, 'unstable'), (120, 'experimental-debug'), (120, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.19.0-5-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages caja depends on:
ii  caja-common           1.22.3-1
ii  desktop-file-utils    0.24-1
ii  gvfs                  1.42.1-3
ii  libatk1.0-0           2.34.1-1
ii  libc6                 2.29-7
ii  libcairo-gobject2     1.16.0-4
ii  libcairo2             1.16.0-4
ii  libcaja-extension1    1.22.3-1
ii  libexempi8            2.5.1-1
ii  libexif12             0.6.21-5.1
ii  libgail-3-0           3.24.13-1
ii  libgdk-pixbuf2.0-0    2.40.0+dfsg-2
ii  libglib2.0-0          2.62.4-1
ii  libglib2.0-bin        2.62.4-1
ii  libglib2.0-data       2.62.4-1
ii  libgtk-3-0            3.24.13-1
ii  libice6               2:1.0.9-2
ii  libmate-desktop-2-17  1.22.2-1
ii  libnotify4            0.7.8-1
ii  libpango-1.0-0        1.42.4-7
ii  libpangocairo-1.0-0   1.42.4-7
ii  libselinux1           3.0-1
ii  libsm6                2:1.2.3-1
ii  libx11-6              2:1.6.8-1
ii  libxml2               2.9.4+dfsg1-8
ii  mate-desktop          1.22.2-1
ii  shared-mime-info      1.10-1

Versions of packages caja recommends:
ii  gvfs-backends  1.42.1-3

Versions of packages caja suggests:
ii  engrampa            1.22.3-1
ii  gstreamer1.0-tools  1.16.2-2
ii  meld                3.20.1-1

- -- no debconf information

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