Member Avatar for sidestrand

I have a WD external usb drive attached to my BT Home Hub 3. It's formatted to ext4. I've set fstab to mount the drive and can see it and open folders, but I cannot copy to it.

The file permissions ('rwx') are all in my name for the drive and folders, but still it says that I don't have permissions. I've tried copying as root but write access is still denied.

ls -la confirms that the files are in my name and my group, but when I look at the properties in Nautilus it doesn't show read / write permissions.

Any advice gratefully received.

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  • Latest Post Latest Post by Wil 0' Wisp

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— building on ’s point about the Hub re-mapping permissions, here are focused diagnostics and practical fixes that resolve this class of problem.

  • Verify how the share is mounted on your machine (look for ro, cifs/smb, or unexpected uid/gid): 

    mount | grep /path/to/mountpoint
# or
df -hT /path/to/mountpoint

  • Do a simple write test and check the kernel log for errors: 

    sudo touch /path/to/mountpoint/.write_test
dmesg | tail -n 20

    If touch fails even as root, the export is being presented read-only by the hub or the server side is denying writes.

  • If the share is SMB/CIFS, test with smbclient to see how the hub presents the share:

    smbclient -N //ROUTER_IP/SHARE -c "ls; put localfile remotefile"

    That will reveal whether the hub allows authenticated writes or only guest access.

Common fixes

  • If the hub is exposing the disk as a guest-only read-only export, either change the hub USB/share settings (if available) or stop using the hub as the SMB server. One low-risk workaround is to mount the hub export with explicit CIFS options that force ownership on the client:
    # example fstab line (replace IP/share and uid/gid)
//192.168.1.254/USB  /mnt/wd  cifs  guest,iocharset=utf8,uid=1000,gid=1000,file_mode=0775,dir_mode=0775 0 0
  • A more robust solution is to connect the drive to the Linux box and share it from there via Samba (no ext4-to-SMB mapping surprises). Minimal share example:
    [WD]
 path = /mnt/wd
 read only = no
 guest ok = no
 create mask = 0644
 directory mask = 0755
 valid users = youruser

Cautions: reformatting the drive to FAT32/NTFS may make the hub happier but destroys POSIX permissions and may lose data — back up first. If files written directly to the disk don’t appear via the hub, the hub may be failing to mount or caching; check the hub’s USB status page, reboot the hub, or remount the export after a clean unmount.

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Member Avatar for Wil 0' Wisp

Try plugging the USB stick into a local USB port on a PC or a laptop and see if you can write to it there first. These type of device have a web interface, you might want to check the guest access rights. The "network" drive may not be useable as the logged on user!
Your not giving any much away apart from the fact you are using a quote 'now defunct file manager product' which looks like MAC software so this is Mac problem or is it Linux?

Member Avatar for sidestrand

Thanks for responding. I can read and write to the usb disk when it's plugged directly into my laptop via USB2. The odd thing is that the newly copied files don't show up when I view them over the BTHUB3, which makes me think that what I'm seeing is some sort of cache. I don't think I've used the phrase 'now defunct file manager product' - must be someone else! I'm using Linux Mint Maya.

Member Avatar for Wil 0' Wisp

That means it is the way the BT Hub is interpolating the security on the stick. The rights are not correctly seen by the linux o/s they most likely have ben written for windows clients, (well MS rules OK or does it?) Can you view the stick from the web interface of the Hub?

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