Re: Finding parameters of existing ext2fs partition

["Thomas Mueller" <mueller6725%twc.com@localhost>]

> > Question is how to determine what this format is for an already existing ext2fs filesystem, either from base system or from e2fstools package.

> One solution would be to reboot with a GNU/Linux live/rescue system and check from there with `tune2fs -l`.

> The other way around, I do deploy NetBSD systems with an ext2fs root from GNU/Linux and I need to disable a few EXT2 features that are not recognized by NetBSD.

> By default, when creating EXT2 from Lignux, one would get

>  	Filesystem features:      ext_attr resize_inode dir_index filetype sparse_super large_file

> I disable those two features

>  	mkfs.ext2 -O^dir_index,^ext_attr

> so in the end I get

>  	Filesystem features:      resize_inode filetype sparse_super large_file

> > Problem is when I write to an ext2fs filesystem from NetBSD, I may get errors, especially with a big, complicated write that would occur with "git pull".

> I got no errors and use it even in production - it is just very slow - luckly it's mostly an idling dedicated box.

> The only issue I have is with GIT also.  I cannot review e.g. `git status` nor anything, although nothing crashes here.  Apparently GIT is using some file-system features that we don't have.  Otherwise I am good, everything works.

> > My hypotheses is that the filesystem was formatted from FreeBSD with their default -r 1, comparable to -O 1 in NetBSD.

> If you're playing with FreeBSD, why don't you just use FFS?  Theirs and ours is pretty much compatible.

> > I want to create a Linux ext2fs that can be safely written to from NetBSD.

> As shown above, I prepare the fs from GNU/Linux.  I've documented it here:

> http://pub.nethence.com/bsd/malabar
> http://pub.nethence.com/bsd/ext2fs
> https://pub.nethence.com/bin/bsd/netbsd.install.bash.txt

> as for FreeBSD with UFS2 is here:

> http://pub.nethence.com/bsd/malabar.freebsd

> Pierre-Philipp

Reason for making ext2fs partition from NetBSD or FreeBSD and then running git was to download and follow Linux software repositiries that would later be accessed from Linux.  Linux can read but not write to a BSD (FFS/UFS) partition.

I might also need to create a root filesystem for a cross-compiled Linux from NetBSD or FreeBSD.

I think I might have to use "-O 0" for newfs_ext2fs from NetBSD, but subsequently, using the Linux root file system, would not need to be so fettered, would switch to more up-to-date options for Linux.

I have not recently, since switching from MBR and GPT, and not using BSD disklabel, had any problems regarding interoperability between FreeBSD and NetBSD file systems.  Traditional disklabel or bsdlabel has long been deprecated on FreeBSD.  I would be quite content to never again see a traditional BSD disklabel.

Tom