mount -o remount,rw doesn't stick

[Michael Giuffrida]

I have a Pixel in dev mode. Suddenly I'm having trouble writing to files in /sbin. I cannot mount the filesystem R/W after making a change.

I've removed rootfs verification (and have been able to deploy Chrome from my Ubuntu machine). Upon booting, I can change one file, but then the file system locks down:

# echo "test1" > /sbin/test1

# cat /sbin/test1

test

# echo "test2" > /sbin/test2

-bash: /sbin/test2: Read-only file system

# echo "test2" > /sbin/test1

-bash: /sbin/test1: Read-only file system

# mount -o remount,rw /

mount: cannot remount /dev/ROOT read-write, is write-protected

After a reboot, I can repeat this process. My end goal is to edit /sbin/session_manager_setup.sh but as soon as I open it vim freaks out.

Contents of /etc/fstab:

/dev/BOOT /boot ext2 noauto,noatime 1 2

/dev/ROOT / ext3 noatime 0 1

/dev/SWAP none swap sw 0 0

/dev/cdrom /mnt/cdrom auto noauto,ro 0 0

/dev/fd0 /mnt/floppy auto noauto 0 0

^ This looks weird, but my HP Chromebook 14 looks the same and works fine.

I wanted to run fsck, so I tried creating a bootable Ubuntu USB drive but the Pixel refuses to boot that; I press Ctrl-U at the dev screen, the screen goes black, the activity light on the USB drive blinks once and the Pixel emits a single low-pitched beep before returning to the dev screen. (I have run chromeos-firmwareupdate --mode=todev and crossystem dev_boot_usb=1 like I usually do.)

Any tips on what's wrong before I reimage the machine?

Thanks!

[Stéphane Marchesin]

Last time it happened to me, my SSD was dying and my kernel was
remounting the SSD as read-only every time I tried writing something.
You should see a trace of that error in your dmesg if that's the case.

Stéphane

[Michael Giuffrida]

Thanks Stephane.

My file system was corrupted -- Stephane running fsck and ignoring the scary "you should never do this" warning did the trick.