GUI console goes "Error 500: unable to open file '/var/tmp/pve-reserved-ports.tmp.791677' - Read-only file system)"


May 16, 2023
PVE 8.0.4, single node, my homelab. After four months of perfect uptime, today I can't enter the console via GUI due to "Error 500: unable to open file '/var/tmp/pve-reserved-ports.tmp.791677' - Read-only file system)"

dmesg reveals a bunch of these:

EXT4-fs warning (device dm-3): ext4_dirblock_csum_verify:404: inode #1835765: comm rm: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs error (device dm-3): htree_dirblock_to_tree:1080: inode #1835765: comm rm: Directory block failed checksum

smartctl -a /dev/sda and sdb reveals no errors.

df reveals this (doesn't look like a full disk, does it?):

root@pve:~# df
Filesystem 1K-blocks Used Available Use% Mounted on

udev 8107064 0 8107064 0% /dev
tmpfs 1629024 1912 1627112 1% /run
/dev/mapper/pve-root 40606184 17761160 20750128 47% /
tmpfs 8145112 45648 8099464 1% /dev/shm
tmpfs 5120 4 5116 1% /run/lock
/dev/sda2 1046508 348 1046160 1% /boot/efi
/dev/fuse 131072 108 130964 1% /etc/pve
tmpfs 1629020 0 1629020 0% /run/user/0

The system is up and running, VMs and LXCs are on a different NVMe drive and writable. There has NOT been a blackout nor any reboot in 4 months, the error just appeared today.

I'm afraid to reboot the system. Anything I can do first? Thanks!
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e2fsck -n /dev/sda
Warning! /dev/sda is in use.
ext2fs_open2: Bad magic number in super-block
e2fsck: Superblock invalid, trying backup blocks...
e2fsck: Bad magic number in super-block while trying to open /dev/sda

The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem. If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
e2fsck -b 32768 <device>

Found a gpt partition table in /dev/sda
In fact ALL e2fsck checks of drives return "ext2fs_open2: Bad magic number in super-block", including the NVMe that holds the VMs.
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You need to run the fsck on your partition, not the disk itself, in your case /dev/mapper/pve-root, yet you need to run it in a recovery environment. I hope you have up-to-date backups.
I was able to fix it from Proxmox Rescue USB. There was a lot of errors but second pass of fsck did not reveal any more errors. Do you think it's okay? A complete wipe or even replacement of the (new! 120 GB Apacer SSD) drive would be better, right? Data is on a different NVMe (and mostly backed up).
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