New filesystem: Btrfs!

StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

Since frenkel disappeared, can someone post ebuilds for all of btrfs: The kernel module and utils?

Thanks

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

sure. Here are the current versions from our overlay...

sys-fs/btrfs-0.8.ebuild:

StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

Great.

Thanks. These will go to good use frying my root partition. :twisted:

Nah. I think I will put portage on it and maybe /var/tmp/portage. That folder gets used a lot, so it would be a great test, and /var/repos is large since that's where distfiles is and I never clean that out. hmmm. I could delete all distfiles and then do emerge -d world. That would test the partition out. Oh yeah.

*runs off to screw up system*

StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

Sorry to double post, but I can I give subpartitons labels. I have /dev/hda6 formatted as ext3 for /var/repos and it's called "Repo". My fstab is all setup to mount by label, so can I format /dev/hda6 as btrfs, then divide that up into Repo and /var/tmp/portage? Currently /var/tmp/portage is mounted in ram, so I have no other physical location except under the main / (/dev/hda5). All the other partitions are all used for important stuff, so I don't want to resize or move them.

StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

I try to make a new subvol and it says that ioctl returns 0 and I don't see anything when I do a ls. I don't even see the default subvol. :S

Thanks

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

You might want to try mounting them with "-o subvol=name" as this works now. I am using btrfs on /usr/portage and /var/tmp/ccache and it works great

Rei
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StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

I can mount the subvols directly now, but I thought the btrfs site said that we were able to see the subvols, if we have the main partition mounted and we did a "ls" in that mount point. :S

Also, do we need to have the main partition mounted to be able to mount and use the subvols? So I have the btrfs on /dev/hda6, do I need to mount hda6 to some place then mount the subvols to where I want them? Or can I not have the hda6 mounted, and just mount the subvols?

I am thinking this might be cool to have a btrfs partition and make /var /home /usr /... all the stuff under root and mount those as subvols. Then you could snapshot each subvol as needed. Like /etc changes the most with new configs and whatnot, so that would be great to snapshot more often in case you botch an update.

Thanks for all your help.

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

You do not need to mount the main partition now. You are just mounting the subvolumes to where you need them.

Concerning the main partition, I am not sure if this is a bug or a new feature that you do not see the subvolumes anymore. Anyways - stay tuned for new releases

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StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

Cool! Thanks! I guess I need to post on the ML about seeing subvols by using "ls".

Anyways, I swear that my repos on btrfs is much faster than when the repos were on reiserfs 3.x (whatever the latest 3.x version is).

Searching portage is extremely quick compared to what it used to be. I am sold on this filesystem.

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

I did Live-Ebuilds for fetching the latest development snapshots of btrfs and btrfs-progs from the mercurial repositories as I discovered a bug (or the bug discovered me) that causes a kernel oops which was fixed soon after the 0.8 release.

Feel free to use/improve them...

sys-fs/btrfs-progs-9999.ebuild:

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

Just a few tidbits about the ebuilds.

On btrfs-progs, you do not need the src_unpacked() function.

For the btrfs module ebuild, you do not need both src_unpack() and src_install() functions. In pkg_postinst(), you need to include the function call to linux-mod_pkg_postinst before the three ewarn statements. I think that function call is missing in the 0.8 ebuilds, and it is important because it calls depmod, which explains why I had to manually run depmod to get btrfs to load.

That function should go in the 0.8 ebuild as well if it's missing.

Thanks for posting these. I think I might check out the live sources. ^^ Hmmm ... what would be cool is to have both installed and running, the "stable" 0.8 release on /var/repos and the "live" module on some test partition.

I don't think that is possible though.

Cheers.

StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

I fixed up the live ebuilds to include the functions and the correct src_uri.

sys-fs/btrfs-progs-9999.ebuild

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

Will test them

But there are some things on my mind we should take care of:

Is there a way to add the modules to the list of modules to be rebuilt by module-rebuild
The btrfs Makefile should be patched to care for /usr/src/linux instead of the current kernel (gentoo way)

Rei
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StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

In this function:

ToeiRei · Veteran Joined: 03 Jan 2005 Posts: 1113 Location: Austria

Thanks a lot, StifflerStealth.

I usually do not do that much ebuilds - in fact, the btrfs ebuild was my first one and I was happy that it worked.

Rei
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StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

You're welcome.

I work a lot with ebuilds. I know a lot of tricks with them.

Although, now that Waninkoko included BTRFS patch in 2.6.23-kamikaze3: http://forums.gentoo.org/viewtopic-p-4384529.html the btrfs module ebuild might become obsolete. :lol:

Maybe not.

But, it's patched into that kernel if you want to look at the patch and add it your own kernel, you can do that.

I converted several people to BTRFS in the 2.6.23-kamikaze2 thread.

Personally, my thoughts are that BTRFS and ext4 are really fast filesytems. When ext4 is final, it will be my new root FS. BTRFS is really fast for portage, and it may become my root fs some day. I'm glad I tried them. Reiser4 gave me some troubles awhile back and I haven't been brave enough to try it again. I basically lost my whole system back in the 2.6.8 days. R4 may be more stable now, but I think these two fs's are fast enough and definately stable with features I like, like subvolumes for BTRFS and stuff.

My two cents.

wrc1944 · Posted: Wed Oct 17, 2007 9:10 pm Post subject:

StifflerStealth,
So, if I understand correctly, your btrfs-progs ebuild above will work with kamikaze3, or is that incorrect- or we don't know yet and I just need to try it?

I just compiled kamikaze3, and under File Systems enabled btrfs as a module (wouldn't let me compile it in the kernel). Can we now use it like we do any other FS, and just do mkfs.btrfs /dev/sdax, for say /usr/portage?
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StifflerStealth · l33t Joined: 03 Jul 2002 Posts: 954

You should be able to.

I asked Waninkoko what version he used to make the patch but he seemed to skip over that question in that post. :roll:

I think he used the svn copy because I mentioned that was the most stable, so the above ebuild should work. I don't remember the difference between v0.8 and svn of the progs. :oops:

But, I do think it will work. I still need to update my kernel to try it out. I just can't reboot my computer at the moment.

Still, I think it's great that Waninkoko was able to patch in BTRFS even though it's only available as a module. It really helps on rebuild and reboot.

You can also make subvolumes with BTRFS, so you can make two subvols: one for portage and one for /var/tmp/ccache.

That's explained somewhere in this thread.

I like them. It keeps my data separate and allows snapshoting of different subvols, so you don't need to snapshot the entire partition.

In theory, one could make each revision of the entire portage repository (minus the distfiles) a snapshot, so if a package gets removed, you just mount that snapshot and point to it in the overlay directory. So, it's like built in versioning, but more compatible with emerge.

That way, something like winamp would never be gone, per se and all it's depends are still available as well. Interesting thoughts ... Hmmm ....

wrc1944 · Posted: Thu Oct 18, 2007 5:12 am Post subject:

I'm having problems with the btrfs-progs ebuild. I made the /usr/local/portage/sys-fs/btrfs overlay directory, cd'd in and copied your ebuild there, and tried to digest it (I've done that lots of time). First I had problems like this:

Matteo Azzali · Retired Dev Joined: 23 Sep 2004 Posts: 1133

@wrc1944: