Opening Some Files on External ext4 Hard Drive on a Chromebook

[Paul Boniol]

So... I've got an external drive I used to copy files from my Linux computer. The partition is ext4.

Some directories I can access on the Chromebook, but others I can't.

I tried changing all the directory permissions to 0777 and all the file permissions to 0666 on the problematic directories/files, but I am still getting "Your file couldn’t be accessedIt may have been moved, edited, or deleted.

ERR_FILE_NOT_FOUND"

Everything I've found online points to not being able to mount the whole partition. But it is mounting, and other directories (which were close if not identical permissions) I can read just fine.

I know Chrome OS is a bit out of scope, but hoping someone has some idea what else may be wrong.

---Paul.

[Justin W Elam]

Paul

I would attempt seeing if you can mount the drive from another workstation that isn't a Chromebook

Once you know that you can mount the disk

Then you should be able to use the Chromebook Linux Partition Terminal software to access the drive however you typically have to use the Chromebook File Manager sometimes as well as there are some differences as each is it's own container or VM/slice

It may be easier to just copy what you need and use a sneaker net FAT usb sometimes

Ext4 can work

However Chromebook and ChromeOS has depreciated ext filesystem for whatever reason

Dev-Mode and Crouton should be ok 

And it Uses 

. /media/ &

mnt/chromeos/removable

Remember to use the Chromebook file manager and right click /hamburger 

"Share with Linux" 

This creates another symbolic link alias between the two containers 

Another option is to just install Linux Debian container onto the Chromebook in options 

Then install nano qemu-system qemu-utils python3 python3-pip

And you should be able to boot any "qemu container "you want 

A LA VMware Suse or whatever floats you boat.  And then you have another Linux machine that should be able to natively mount the ext4 partition 

Or similar tiny core Linux busybox or similar O/s 

You probably could port IBM os/2 warp on it if you want to 

Another option would be something like FUSe, or NfS socket or plan9 9Pfuse if you are into plan9.
And serve it over the local network

Cheers from J

%

ChromeOS will no longer support ext2/3/4 on external drives/SD cards. Only fully supported filesystems are FAT and NTFS. 

X-post  /r/linux

%

[Csaba Toth]

Have you tried to check file system integrity with a regular Linux. Normally it'd signal if something smells fishy with it right after mount (for example mounting read only) but you never know.

Especially if it's removable, even though ext4 supposed to be resilient and it's a journaling file system it can still falter if it's not synced well before unplug.

Also consider bad sectors, look at SMART data.

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[Dan Bacus]

Hi Paul,

   I hate to even ask because they are the bane of my existence, but have you checked ACLs just in case they are denying access somehow?  Especially at a directory level?  (Lord, but I hate those sneaky little buggers...)

   Has a user been defined to match the UID of the file owner from the source system?  If not, maybe "chown -R 0:0 /mount/point" to get everything owned by root, and a group of root, at least?  I claim to know absolutely nothing about Chrome OS, so I have no idea how it deals with file access when ownership of a file can't be traced back to a valid user name.

   Less likely to be an issue, but have you done a "ls -ld /mount/point" to see permissions on the mounted filesystem's mount point?  Back when I taught the troubleshooting class for Sun Microsystems, one of the problems we gave students was doing "chmod 0000 /", resulting in only the root user being able to log in.  No other non-root users could log into the system.  Troubleshooting as root, students would check perms on /etc, /home, /usr, /etc/passwd, /etc/shadow, and the like; but only rarely would someone think to do "ls -ld /" to look at permissions there without a little nudge from the old instructor.  If you can't read / - well then you can't read anything anywhere below it either...

   I'm sorry that I could not be of any more help.  Best of luck to you!

Dan

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[Paul Boniol]

Thanks for all the replies! If I was home, this would have been a few minutes to check/verify. However I'm out of town, and have a Microsoft Surface Windows machine from work, and a Chromebook (and today I was babysitting my 1 yo toddler granddaughter so progress has been excruciatingly slow). I'm trying to create a bootable USB drive on Windows now, but now that's throwing an error when it gets 20% in. Fun times.

I don't ever remember setting up any ACL's for that directory... Whenever I looked at them in the past I thought they'd be a headache and abandoned the idea. It is a /home/user/ directory that I backed up, have chmod commands in the script, had verified working months ago, but foolishly assumed everything would still be working now...  Once I can get to it as root, I can verify perms an chown --recursive too.

Ugh! I hadn't seen ChromeOS decided to deprecate ext4 support. *sigh*

Hopefully I'll have positive news soon... Of course I'm going back home this weekend. I can just access the files directly from the server once I'm back

---Paul.

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[Csaba Toth]

Wow, I didn't even know ext4 could be not supported on Chrome OS.

There was a community push-back: https://www.networkworld.com/article/931460/chromeos-team-listens-to-linux-community-brings-back-ext2-3-4.html

Was the push-back successful? I sold my ChromeBook so I cannot test it.

If it's not supported then it'd be weird if it could be mounted at all.

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[Paul Boniol]

It still mounts currently on my Chromebook, I'd be disappointed if they dropped ext4 support in the future, we'll have to see what they do.

Crouton shows the /home/user directory has 0754 permission... I can see the files listed in Chrome file manager, but not in Crouton. My Crouton user is a member of the group number for the directory, so if this were real Linux, it should still let me have access. And not surprisingly Crouton won't let me sudo chmod the directory.

I did get Ubuntu on the thumb drive, but then Windows recovery mode wouldn't let me navigate, by keyboard or trackpad or touch screen, to any of the options. The only thing I could do was hold the power button down to get it to turn off and reboot. I think I'll just have to wait till I get home to fix the permissions, or verify something isn't right.

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[Csaba Toth]

Got it, so the terminal and your developer Crouton VM is sandboxed within the main OS?

I meant to fsck with a regular Linux installation, not with ChromeOS, in order to rule out any logical FS error.

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[Paul Boniol]

Now that it's practically time to go home, I have: 

a) Finally been able to successfully install Ubuntu under Windows wsl. (That has been a back burner problem for a while now, Some Windows update in the distant past had essentially disabled installing distros under wsl on my work computer, so some later update fixed that.)

b) Mounted the ext4 partition with wsl

c) chmod the directories to have o+x perms.

d) I verified there are chmod statements in the script for the directories in question. It is unknown why they weren't set as directed. I'll have to try to figure that out when I get home to a real Linux install.

e) Still unknown why Windows won't let me use the keyboard or mouse on the Surface to select options on the Bitlocker screens (to be able to boot from the USB drive), but I have seen a recent update caused issues with some people having to enter their Bitlocker key after rebooting. >< Ouch! So possibly related.

Paul

On Tue, Jul 23, 2024 at 11:35 PM Paul Boniol <paul....@gmail.com> wrote: