Re: Errors on newly created file system

[Ferry Toth <fntoth@gmail.com>]

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Op donderdag 24 april 2025 01:24:23 CEST schreef Qu Wenruo:
> 
> 在 2025/4/24 01:36, Ferry Toth 写道:
> > Op woensdag 23 april 2025 00:00:36 CEST schreef Qu Wenruo:
> > 
> [...]
> 
> > 
> >  > > Yocto users on Scarthgap (5.0 LTS) with version 6.7.1 may copy the
> > 
> >  > > recipe meta/recipes-devtools/btrfs-tools/btrfs-tools_6.13.bb from
> > 
> >  > > walnascar or 6.14 from master. If they are building additional tools
> > 
> >  > > that use headers from this package like btrfs-compsize these may break.
> > 
> >  > >> Thanks,
> > 
> >  > >> Qu
> > 
> > 
> > While here, am I right that we can not generate the rootfs with 
> > compression on?
> > 
> > 
> > Reason I ask is, Yocto of course builds the rootfs and than has 
> > mkfs.btrfs create the image. But it runs as unprivileged user, so can 
> > not do mount.
> > 
> > And then can not do defrag.
> 
> We have this feature recently thanks to Mark!
> 
> In the latest release v6.13, there is a new option "--compress" added to 
> mkfs.btrfs, which must be used with "--rootdir".
> 
> And the result is exactly what you expected, mkfs.btrfs will try to 
> compress the file extents at runtime.
> For uncompressible data, it will detect at the beginning and fallback to 
> uncompressed data instead, exactly like the kernel.

That is great, thanks!

> But considering how new this feature this, it will be appreciated if 
> Yocto guys can do some extra testing to make sure nothing is broken.
> (Normally a btrfs check after the mkfs will be good enough)
> 

I will test this.

In the meanwhile I found another problem (and I am not the first it seems see
/https://stackoverflow.com/questions/79475262/yocto-root-filesystem-ownership-issue/79590289#79590289/[1])

Yocto uses pseudo to fake root ownership. Even though the directory to be copied into the new fs is owned by an unprivileged user inside the btrfs image the files are owned by root, when created by mkfs.ext4 and mkfs.btrfs.

Except with newer mkfs.btrfs (I tested using 6.13) the files are owned by the unprivileged user. 

The result is, the image will not boot correctly.

> Thanks,
> Qu
> 
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[1] https://stackoverflow.com/questions/79475262/yocto-root-filesystem-ownership-issue/79590289#79590289

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