all btrfss on removable drives fail to mount with 25.10

[jlittle]

Before release upgrading to 25.10, at the beginning of the month, I used btrfs send -p/receive to revise all my backups, with no incident. They mount through USB3 ports. On Monday I thought is was about time to do a backup, but the backup volume would not mount cleanly. Normally when I plug in such a removable drive, the removable drive system pops up and offers to mount and open. But now

[ 1170.406704] I/O error, dev sdd, sector 291470176 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406736] sd 6:0:0:0: [sdd] tag#1 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406743] sd 6:0:0:0: [sdd] tag#1 CDB: Read(10) 28 00 12 03 bf e0 00 00 20 00
[ 1170.406746] I/O error, dev sdd, sector 302235616 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406767] sd 6:0:0:0: [sdd] tag#2 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406773] sd 6:0:0:0: [sdd] tag#2 CDB: Read(10) 28 00 12 04 c5 60 00 00 20 00
[ 1170.406776] I/O error, dev sdd, sector 302302560 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406791] device offline error, dev sdd, sector 302303136 op 0x0:(READ) flags 0x80700 phys_seg 12 prio class 2
[ 1170.406796] sd 6:0:0:0: [sdd] tag#3 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406801] sd 6:0:0:0: [sdd] tag#3 CDB: Read(10) 28 00 12 04 c0 a0 00 00 80 00
[ 1170.406805] I/O error, dev sdd, sector 302301344 op 0x0:(READ) flags 0x80700 phys_seg 16 prio class 2
[ 1170.406814] device offline error, dev sdd, sector 302303264 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406825] sd 6:0:0:0: [sdd] tag#4 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406825] device offline error, dev sdd, sector 302314368 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406828] device offline error, dev sdd, sector 302314432 op 0x0:(READ) flags 0x80700 phys_seg 8 prio class 2
[ 1170.406834] sd 6:0:0:0: [sdd] tag#4 CDB: Read(10) 28 00 12 03 f3 40 00 00 20 00
[ 1170.406837] device offline error, dev sdd, sector 302385088 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406837] I/O error, dev sdd, sector 302248768 op 0x0:(READ) flags 0x80700 phys_seg 4 prio class 2
[ 1170.406860] sd 6:0:0:0: [sdd] tag#5 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406866] sd 6:0:0:0: [sdd] tag#5 CDB: Read(10) 28 00 12 03 bf 40 00 00 20 00
[ 1170.406881] sd 6:0:0:0: [sdd] tag#6 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406887] sd 6:0:0:0: [sdd] tag#6 CDB: Read(10) 28 00 12 04 2f 80 00 00 20 00
[ 1170.406901] sd 6:0:0:0: [sdd] tag#7 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406907] sd 6:0:0:0: [sdd] tag#7 CDB: Read(10) 28 00 11 5f 7f e0 00 00 20 00
[ 1170.406917] Buffer I/O error on dev sdd1, logical block 0, async page read
[ 1170.406922] sd 6:0:0:0: [sdd] tag#8 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406927] sd 6:0:0:0: [sdd] tag#8 CDB: Read(10) 28 00 12 03 e9 60 00 00 20 00
[ 1170.406941] sd 6:0:0:0: [sdd] tag#9 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=36s
[ 1170.406948] sd 6:0:0:0: [sdd] tag#9 CDB: Read(10) 28 00 12 03 c0 60 00 00 20 00
[ 1170.407604] /dev/sdd1: Can't open blockdev
[ 1170.426809] Buffer I/O error on dev sdd1, logical block 36429080, async page read zz0.licdk07j14ezz

• it does not
• if I click on the removable drives icon, I see a mount and open option, if clicked it says checking for a while, but does nothing
• persisting with mount ans open, the partition now says "You are not authorized to mount this device".
• attempting to use

• • sudo mount /dev/sdd1 /mnt/scratch
    • mount: /mnt/scratch: /dev/sdd1 is not a valid block device
    • dmesg(1) may have more information after failed mount system call.
  • running sudo dmesg produces a bunch on errors
• I found some unallocated space on the end of the drive, and used the partition manager to create a new btrfs there. It behave the same way.
• Now, at first I thought I had some kind of drive failure, but then I tried another, to get the same errors.
• If I persist with a fresh boot and going directly to sudo mount, it seems to work, but fails soon after trying to copy files.
• Then a medical issue intervened, and now on Friday I'm looking in to it.
• I have a vanilla fresh install of 25.10; it fails the same way.
• No problems accessing a btrfs that's an internal drive.
• No problems mounting a NTFS removable drive.
• I have a 25.04 install, which has no trouble mounting the drives normally.

So 25.10 has a big problem on my hardware. I'd have thought there'd be lots of users reporting this problem, so why me, especially with the fresh install?

Using 25.04, I can complete my backups, I think, but my confidence has been shaken.

Can anyone on 25.10 report whether they can mount via USB a removable drive that has a btrfs on it?

I'll be lucky if someone here on KFN has answers, but maybe someone has ideas on what to do next.

[Snowhog]

Just formatted a 32GB USB thumb drive on my Desktop PC (running Kubuntu 24.04 with btrfs as the FS) as btrfs using KDE Partition Manager. Inserted the drive in my Laptop (running Kubuntu 25.10 with btrfs as the FS) and selected Mount and Open in the Disks & Devices popup window. Dolphin opened with the device. I created a text file. No issues.

When I formatted the thumb drive I specified that Everyone would have access.

[jlittle]

Thank you, you put me on to something.

When I formatted the thumb drive I specified that Everyone would have access.

If I do the same, it works. However, chmod 777 on a failing btrfs does not change anything.

Investigation on the issue is complicated by the fact that the mount failure poisons Linux's view of the device, and if the light on the drive is flashing, on the drive too. sometimes the device disappears from /dev, and unplugging and plugging in doesn't bring it back. I have to power off both computer and device. Powering of the computer often gets stuck, even with the device unplugged, requiring use of the power off button. This means that I should be able to mount the drives using sudo mount, so long as I haven't previously failed to mount since power on.

If you would do the exercise again, this time specifying "root access only", I'd appreciate it.

Does anyone no where this permission that stops a normal udisks mount is? It's not just the permission of /mnt/x.

[jlittle]

This means that I should be able to mount the drives using sudo mount, so long as I haven't previously failed to mount since power on.

Indeed, by having a clean mount using sudo, I have done the send/receive I tried on Monday.

[Snowhog]

If you would do the exercise again, this time specifying "root access only", I'd appreciate it.

Just did. Dolphin sees the plugged in thumb drives just fine. I can open it (it's empty, being just formatted), but "I" can't do anything else; it is owned by root. Right-clicking on the drive, the + Create New entry is greyed out.

The device mounts to /media/paul/a21ed928-8447-4197-b466-22b38655174a/
The a21ed.. directory is owned by root.
I open a terminal at that location and create an empty text file: sudo touch text.txt
The file is owned by root.
I change ownership of the file to paul: sudo chown paul:paul test.txt

In Dolphin, the file appears, but that doesn't give me "non-root user" access to the directory it is in. Expected.
I return to the location in the terminal and cd to /media/paul and chown the a21ed.. directory to myself: sudo chown paul:paul a21ed928-8447-4197-b466-22b38655174a

The drive is now owned by me and I can manage it as expected.

[jlittle]

My latest workaround is to use an /etc/fstab entry with noauto,user. So long as udisks does not attempt a mount, it works fine. I'll set up entries for all the btrfs external drives; since I use labels this is clean and easy.

I'll investigate further, at a more relaxed pace.

[oshunluvr]

Seems like /usr/lib/udev/rules.d/80-udisks2.rules might be a good place to start looking.