This is a follow up question to this Q/A.

I tried the command on my laptop it worked:

setfacl -m 'u:programX:rwx' /etc/NetworkManager

I checked that my embedded device had acl installed and marked correct.

But I'm finding when using the command on the embedded device I get setfacl: /etc/NetworkManager: Operation not supported.

When I check man setfacl my version of acl seems to support the -m flag.

Why wouldn't acl on the device support the operation, when it works fine on my laptop?

Result of mount | grep -w /:

/dev/block/mtd/by-name/linuxroot on / type ext4 (rw,relatime,barrier=1,data=ordered)
  • What's the output of mount | grep -w / ? Commented Nov 3, 2017 at 20:30
  • @MarkPlotnick added to question Commented Nov 3, 2017 at 20:31
  • What is the output of tune2fs -l /dev/sdaX | grep "Default mount options" replace sdaX with your device.
    – GAD3R
    Commented Nov 3, 2017 at 20:57
  • @GAD3R it returns tune2fs: No such file or directory while trying to open /dev/sdaX Couldn't find valid filesystem superblock Commented Nov 3, 2017 at 21:07
  • 1
    This article could help someone with more information linuxsysadmins.com/setfacl-operation-not-supported-in-linux Commented Jan 3, 2020 at 22:20

1 Answer 1


The ext4 code in older kernels (I do not know until when) needs acl as mount option. So you may try:

mount -o remount,acl /


Your fstab contains a line like

/dev/sda3   /  ext4    defaults    0 0

You have to add acl to the options field:

/dev/sda3   /  ext4    defaults,acl    0 0
  • I ran remout but still same result Commented Nov 3, 2017 at 20:48
  • 2
    @PhilipKirkbride Does mount | grep -w / now show acl? Can you add acl to the fstab entry and reboot? Commented Nov 3, 2017 at 20:53
  • It doesn't show acl I will update fstab. Commented Nov 3, 2017 at 20:55
  • Can you leave short note on updating fstab I haven't done that before. Commented Nov 3, 2017 at 20:56
  • 1
    @PhilipKirkbride See the edit Commented Nov 3, 2017 at 21:11

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