Funny thing happened just recently: two of the partitions on my external USB drive became read-only, and if I were to guess, I would say that this happened after updating to CL 42160 yesterday evening. Trouble is, I don’t seem to be able to re-gain ownership using chown.
Now, there are a bunch of partitions on that external drive, and only these two are read only. They are not Ext4, all the rest are Ext4. They are FAT and exFAT.
What can be done?
unmount/fsck/remount
I’m guessing you’ll have something in dmesg about being corrupted and remounted read-only.
Doesn’t seem to work:
dad@DadsGram~ $ sudo fsck /dev/sda1
Password:
fsck from util-linux 2.40.2
exfatprogs version : 1.2.5
/dev/sda1: clean. directories 9, files 29
dad@DadsGram~ $ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sda 8:0 0 3.6T 0 disk
├─sda1 8:1 0 991.6G 0 part /mnt/usb-Micron_CT4000Xxxxxx-0:0-part1
├─sda2 8:2 0 32M 0 part
├─sda3 8:3 0 233G 0 part /home/dad/Downloads/ExternalDwnlds
├─sda4 8:4 0 406.1G 0 part /mnt/usb-Micron_CT4000X8xxxxx-0:0-part4
├─sda5 8:5 0 1.4T 0 part /mnt/usb-Micron_CT4000Xxxxxx-0:0-part5
├─sda6 8:6 0 232.6G 0 part /home/dad/Documents/ExternalDocs
└─sda7 8:7 0 465.7G 0 part /home/dad/Pictures/ExternalPics
sdb 8:16 1 15G 0 disk
└─sdb1 8:17 1 15G 0 part /run/media/dad/OLDSD
sdc 8:32 1 29.7G 0 disk
└─sdc1 8:33 1 29.7G 0 part /run/media/dad/WYZECAM
sr0 11:0 1 43.4G 0 rom /run/media/dad/PINOCCHIO_SIGNATURE_COLLECTION
sr1 11:1 1 1024M 0 rom
nvme0n1 259:0 0 953.9G 0 disk
├─nvme0n1p1 259:1 0 149M 0 part
└─nvme0n1p2 259:2 0 953.7G 0 part /
dad@DadsGram~ $ sudo chown dad /dev/sda1
dad@DadsGram~ $ sudo chown dad /dev/sda
dad@DadsGram~ $ sudo chown dad /dev/sda -v
ownership of '/dev/sda' retained as dad
dad@DadsGram~ $ whoami
dad
Take a look here. You might need to adjust your fstab or mount command so that it gets mounted with the correct UID maps. It’s from an Ubuntu site, but the principles are common to any Linux.
