EROFS-Utils 1.1 Released For This Read-Only Linux File-System

[phoronix]

Phoronix: EROFS-Utils 1.1 Released For This Read-Only Linux File-System

There hasn't been much to report on this year for EROFS as the Huawei-developed read-only Linux file-system with Android devices in mind. But out this week is now erofs-utils as an update to the user-space utilities around this file-system...

http://www.phoronix.com/scan.php?page=news_item&px=EROFS-Utils-1.1-Released

[J.G.]

If you're familiar with Squashfs, as used by many Linux distribution installation discs for example, EROFS is similar to that.

EROFS is aimed at low performance devices and uses little memory usage. On a Raspberry Pi, for example, you can format / as EROFS and send logs over the network, and you update the Pi by writing a new image instead of doing in-place package upgrades. It makes perfect sense for Android devices since they use a readonly root, and I expect EROFS will become the standard for system images in Android in a few years time, with f2fs for the user data.

[discordian]

Yeah, I am already useing Erofs + f2fs (+ overlayfs). Whats hurting most, is lack of docs. I seen "image patching" thrown around without any explanation. What Id hope is that you could attach an "overlay" to an erofs image simply by appending data (like some unique board keys).

That and I am a bit surprised to see that neither squashfs nor erofs seem to be able to dedup blocks (like qemu/mame can do with their disc-image), and this seems like a design limitation. ie. the list of blocks is always related to the directory entry in erofs, you cant do something similar to a hardlink by saying this file is fully (or partly) using blocks from another.

[StarterX4]

It makes perfect sense for Android devices since they use a readonly root, and I expect EROFS will become the standard for system images in Android in a few years time, with f2fs for the user data.

It means no root on Huawei devices, making them a complete crap.

[starshipeleven]

It means no root on Huawei devices, making them a complete crap.

You can't alter root partition on most modern Android devices anyway, even root can't remount it rw, and/or if you change system files the root partition will fail integrity checks at boot and brick the device.

Does not stop rooting from happening, Magisk is a thing since years already https://www.xda-developers.com/what-is-magisk/

[hsiangkao]

Yeah, I am already useing Erofs + f2fs (+ overlayfs). Whats hurting most, is lack of docs. I seen "image patching" thrown around without any explanation. What Id hope is that you could attach an "overlay" to an erofs image simply by appending data (like some unique board keys).

That and I am a bit surprised to see that neither squashfs nor erofs seem to be able to dedup blocks (like qemu/mame can do with their disc-image), and this seems like a design limitation. ie. the list of blocks is always related to the directory entry in erofs, you cant do something similar to a hardlink by saying this file is fully (or partly) using blocks from another.

Actually EROFS supports on-disk dedup by its own metadata, but I'm not sure if such feature is useful or not (If it's useful I will consider it later).
Let's consider dedup + compress, for such case it can be simply compressed.
and compress + dedup (4k), I'm afraid that there are rare exact 4k same compressed blocks.