multi-device btrfs filesystem automatically mounted once for each device

[Glyph Lefkowitz]

If I have a multi-device btrfs filesystem, and I plug it in via some removable interface (for example, USB3), it will automatically mount on the desktop multiple times. For example, if I have a filesystem labeled FooBar on /dev/sdb /dev/sdc /dev/sdd and /dev/sde, it will be mounted as /media/FooBar, /media/FooBar1, /media/FooBar2, and /media/FooBar3. It should show up only once.

It seems like everything still basically works, but I didn't test writing to said filesystem under the different aliases.

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

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[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Dimitri John Ledkov (xnox)]

btrfs package doesn't exist for a long time now.
I don't see any obvious problems with udev rules shipped in btrfs-tools.
udev & udisks are left to inspect.

[Rolf Leggewie (r0lf)]

I can confirm the problem

[Rolf Leggewie (r0lf)]

This is still present in trusty and xenial as confirmed by a DM (me) and a DD -> bug 1550831

[Rolf Leggewie (r0lf)]

moving udisks tasks to udisks2 (udisks was dropped in after vivid, trusty had both udisks and udisks2)

[Rolf Leggewie (r0lf)]

Interestingly enough, one of my trusty computers apparently does not exhibit this behaviour, even though udisks2 is installed. Partitions get mounted via udisks2, too.

Unfortunately, the problem seems to have gotten much worse in the latest development release. Whereas previously, each btrfs device of the btrfs FS would be mounted once, it seems that in artful, one new mount happens every few minutes. I came back to over 20 mounts on a three-device btrfs FS after a few hours. This was on a very recent live CD.

[Alfonso R. Reyes (alfonso-r-reyes)]

The problem is not confined to Ubuntu.
I am seeing the same problem in Fedora SilverBlue 38 and Fedora SilverBlue 39.

The problem is restricted to `btrfs` only; other partitions such as ext3, ext4, NTFS look fine.