Btrfs: Filesystem remounted Read-Only with no apparent reason

fofe1123 · 2025-02-07 20:47:54

Hello everyone,

Today I encountered an issue with my Arch Linux system running on Btrfs. While working (specifically during an exam), my system suddenly remounted the filesystem in read-only mode due to a corruption error. However, after running diagnostics, I couldn’t find any actual issues with the filesystem, nor the disk.

System Information:

Distro: Arch Linux (fully updated)
Kernel: 6.13.1-zen
Filesystem: Btrfs (on a single NVMe SSD, no RAID)

What Happened:

The system became read-only without any apparent cause.

Checking dmesg I found the following log:

[Fri Feb  7 19:02:58 2025] BTRFS info (device nvme0n1p3): bdev /dev/nvme0n1p3 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0

Running

btrfs device stats /

also reported:

bdev /dev/nvme0n1p3 errs: wr 0, rd 0, flush 0, corrupt 1, gen 0

However, a full

 btrfs scrub

completed successfully with no error reported.
Running

btrfs check --readonly --force /dev/nvme0n1p3

found no corruption.

smartctl

also reports no issues with the drive.
It seems also that the filesystem tree was regenerated at the next boot.

Possible Theories:

A transient issue with the Btrfs log tree that caused a false positive corruption report.
A kernel bug affecting Btrfs.
An inconsistency that was resolved by the log replay at mount time.
A temporary problem with the SSD firmware or cache that did not persist.

Questions:

Has anyone else experienced similar behavior?
Could this be a known issue with the kernel / Btrfs?
Are there any additional checks I should run to further diagnose the cause?

I’d appreciate any insights! Thanks in advance.

Last edited by fofe1123 (2025-02-07 20:49:14)

seth · 2025-02-08 15:04:05

Trimming (discard mount option) or APST caused?
Are there any errors pertaining the nvme in the journal?

okram · 2025-02-18 15:41:03

I've had this problem for a long time (over a year). Over time I've tried very many different solution candidates: so far nothing has worked. What makes this very hard for me to debug is the fact that my system is btrfs-only. So, when it happens: no logs...

Edit: I often see this upon resume.

Last edited by okram (2025-02-18 15:42:46)

Mahtan · 2025-08-18 11:10:46

It seems like stats never gets cleaned unless you run

btrfs device stats --reset /mnt/your-array

I got the information from here https://unix.stackexchange.com/question … trfs-devic

Edit: The system suddenly remounting as read-only when using btrfs is a sign that the hardware disk is failing according to a lot of people claiming to know about this issue.

Last edited by Mahtan (2025-08-18 17:53:34)

c>rust · 2025-09-14 07:51:08

I have similar issue with my faulty dell inspiron laptop, where the hard drive will some time disconnect and the filesystem will become readonly and some command will show "input/output error", I have never able to run the scrub command in the senario due to the error above, but running scrub after give no error either

topcat01 · 2025-09-14 18:31:44

In btrfs, due to normal operations, some extents can become unreachable (e.g., bookend extents). If there is a corruption detected in this, then scrub won't show it because it only scans reachable data. The corruption is real (but has not yet affected reachable data), however, and points to either a disk or memory problem.

Last edited by topcat01 (2025-09-14 18:32:29)

c>rust · 2025-10-15 05:33:09

I over heat my asus pc in my bag-pack due to (some suspend fail which probably caused by the Btrfs read only it self (funny cause I originally think it was the other way around))
jounalctl --list-boots https://gist.githubusercontent.com/iamb … tfile1.txt
the first boot with error
https://gist.githubusercontent.com/iamb … tfile1.txt
https://gist.githubusercontent.com/iamb … tfile1.txt
now it show
"EFI stub: WARNING: Failed to measure data for event 1: 0x800000000000000b" after plymouth and before dmcrypt in every boot
- the message apper out of place and dont show up in
/var/boot/log https://gist.githubusercontent.com/iamb … tfile1.txt
and btrfs read-only issue start to appear
and major slowdown
no error scrub
btrfs-check https://gist.githubusercontent.com/iamb … tfile1.txt
and running it a second time show a 200MB error file
it crash again and I got a giant qr https://gist.githubusercontent.com/iamb … tfile1.txt
the boot partition disappear once
install another new identical ssd and boot from it but the
"EFI stub: WARNING: Failed to measure data for event 1: 0x800000000000000b" still appear
boot in linux-lts always show "ASUS" logo when the warning normally appear in linux boot
#It only happen the day I made this post, strange cause all I did was swap the ssd and update and the "EFI stub" messange still appear
edit never mind it happen again:
- every thing slow down at first (might not be relevant)
- froze and crash -> hard shudown
- on reboot only reconize the other disk(I have two disk plug on a thing and then that thing plug on the mother board) the unrecognized disk is brand new btw
- btrfs check give no error(i think, should have taken a photo)
- reboot a gain -> got emergency console (because filesystem become readonly but not the boot partition)

Last edited by c>rust (Yesterday 11:53:59)

seth · 2025-10-15 06:20:50

https://gist.github.com/iambadwithname/ … 9173e8d4ab

Why is that full of escape sequences?
Please post your complete system journal for the boot:

sudo journalctl -b | curl -F 'file=@-' 0x0.st

sudo btrfs check --force /dev/mapper/root                                                                                  3.13.7  12:35 
Opening filesystem to check...
WARNING: filesystem mounted, continuing because of --force

Have you somehow lost your mind? Don't operate on an open FS, let alone non-readonly btrfs-check

c>rust · 2025-10-15 09:20:38

sorry I was editing when it my ASUS crash(again), I'm currently on my DELL, some of them are not final.

Last edited by c>rust (2025-10-15 09:20:56)

seth · 2025-10-15 12:22:25

Ok, but whatever you do: no not run btrfs check on an open filesystem. Certainly not in writing mode. You're risking to make thins much MUCH worse.

zakklol · 2025-10-25 23:04:06

I'm seeing the same behavior, which I initially attributed to the drive in this HP laptop failing. I swapped the nvme drive and I'm seeing the same thing. I even tried ext4 and it eventually gets errors and fails too. With both linux and linux-lts.
All of the laptop's built in memory/storage/mainboard etc tests pass. SMART shows no issues with either nvme I used.

Here's the weird thing: I'm tried Fedora (6.14.0 kernel) and Ubuntu (even using mainline kernel, 6 .17) on the same hardware and they don't have issues.

The laptop was previously running an older un-updated arch install, probably around kernel 6.8. I did a full update and these issues started coming up after. Reinstalled numerous times and every install would eventually run into this (sometimes immediately on first boot).

I'm going to continue to monitor the current Fedora install on it just to make sure the issue isn't just delayed; then I'll see if I can figure out if there's an older arch kernel where it doesn't happen.

topcat01 · 2025-10-25 23:26:03

Likely a hardware issue. I would try disabling the write cache, and perhaps also power management for the disk. If the firmware has updates, then apply them.

seth · Yesterday 10:05:59

SMART shows no issues with either nvme I used.

Please don't paraphrase, https://bbs.archlinux.org/viewtopic.php?id=57855
Also try to disable APST on nvme's, https://wiki.archlinux.org/title/Solid_ … leshooting and ALPM on SSDs, https://wiki.archlinux.org/title/Power_ … Management (choose medium_power if the disk is optimistically awarded med_power_with_dipm)

Arch Linux

#1 2025-02-07 20:47:54

Btrfs: Filesystem remounted Read-Only with no apparent reason

#2 2025-02-08 15:04:05

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#3 2025-02-18 15:41:03

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#4 2025-08-18 11:10:46

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#5 2025-09-14 07:51:08

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#6 2025-09-14 18:31:44

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#7 2025-10-15 05:33:09

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#8 2025-10-15 06:20:50

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#9 2025-10-15 09:20:38

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#10 2025-10-15 12:22:25

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#11 2025-10-25 23:04:06

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#12 2025-10-25 23:26:03

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

#13 Yesterday 10:05:59

Re: Btrfs: Filesystem remounted Read-Only with no apparent reason

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