Hello everyone,

Btrfs v0.14 is now available for download.  Please note the disk format has 
changed, and it is not compatible with older versions of Btrfs.

For downloads and documention, please see the Btrfs project page:

http://btrfs.wiki.kernel.org

The oss.oracle.com Btrfs project page will soon start redirecting here.

v0.14 has a few performance fixes and closes some races that could have 
allowed corrupted metadata in v0.13.  The major new feature is the ability to 
manage multiple devices under a single Btrfs mount.  Raid0, raid1 and raid10 
are supported.

Even for single device filesystems, metadata is now duplicated by default. 

Checksums are verified after reads finish and duplicate copies are used if the 
checksums don't match.

Multi-device design details can be found here:

http://btrfs.wiki.kernel.org/index.php/Multiple_Device_Support

And sample usage to create and add volumes can be found here:

http://btrfs.wiki.kernel.org/index.php/Using_Btrfs_with_Multiple_Devices

I'm putting up some benchmarks of the new multi-device code as the runs 
finish:

http://btrfs.wiki.kernel.org/index.php/Multi-device_Benchmarks

Next up on the Btrfs todo list is finishing off the device removal and IO 
error handling code.  After that I'll add more fine grained locking to the 
btrees.

Thanks to everyone who has helped contribute to and test this release.

-chris
--

[ message continues ]

Hello everyone,

I've rolled up some fixes for older kernels and fixed an uninitialized 
variables in btrfs-progs that could cause an oops on mount.  I'll wait a few 
days to see if other bug reports come in and cut a 0.15 with any other 
critical fixes.

Until then, you can find download information on the important fixes so far:

http://btrfs.wiki.kernel.org/index.php/Hot_Fixes

-chris
--

[ message continues ]

Well it oopses on writes everytime in Ubuntu 8.04 (Hardy). I'd planned
on digging into
it more before spending a bug report, but will send it tonight after
getting to the affected
machine.

With 1 volume on 1 disk, 2 volumes raid1 on 2 disks, or with 2 volumes
raid0 on 2 disks.
something like:
echo omg > /mnt/btrfs/file

Would segfault, exit the current shell, and leave a nice stack trace
in the kernel's ring buffer.

The file gets created as 0 bytes. Unlinking the file works fine via
rm, but any sort of write fails.
Tried and reproduced the bug with stdout redirection, cp, and dd to a
btrfs v0.14 volume.



-- 
Jeff Schroeder

Don't drink and derive, alcohol and analysis don't mix.
http://www.digitalprognosis.com
--

[ message continues ]

This is because ubuntu kernels ship with apparmor, you'll need this patch:

If there is a #ifdef IM_A_UBUNTU_KERNEL I can use, I'll do it.  Jeff Mahoney 
has a similar patch for SUSE that I've been meaning to merge, but I wanted to 
lookup some way to check for ubuntu as well.

-chris

diff -r e7da2489b19b file.c
--- a/file.c	Wed Apr 30 13:59:35 2008 -0400
+++ b/file.c	Thu May 01 12:25:11 2008 -0400
@@ -852,7 +852,7 @@ static ssize_t btrfs_file_write(struct f
 		goto out_nolock;
 	if (count == 0)
 		goto out_nolock;
-	err = remove_suid(fdentry(file));
+	err = remove_suid(&file->f_path);
 	if (err)
 		goto out_nolock;
 	file_update_time(file);
--

[ message continues ]

adding the ubuntu kernel team. BenC or TimG, do you have any
suggestions for Chris?




-- 
Jeff Schroeder

Don't drink and derive, alcohol and analysis don't mix.
http://www.digitalprognosis.com
--

[ message continues ]

Couldn't you #ifdef based on CONFIG_SECURITY_APPARMOR ? This ought to
work for Hardy. However the next development kernel (Intrepid) does not
have the APPARMOR patches, so just knowing that its an UBUNTU kernel is
not specific enough.

rtg
-- 
Tim Gardner tim.gardner@ubuntu.com
--

[ message continues ]

On Thursday 01 May 2008, Tim Gardner wrote:


I've been assuming the apparmor patches change remove_suid even when they are 
not enabled in the config.

-chris
--

[ message continues ]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


Yeah, unless Ubuntu is doing some magic with the function arguments
(which sounds like the fix is worse than the problem), this is true.

- -Jeff

- --
Jeff Mahoney
SUSE Labs
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.4-svn0 (GNU/Linux)
Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org

iD8DBQFIGhmULPWxlyuTD7IRAgJcAJ4zYYcgQ2V0eT6Fv6LstlwpnK9bUwCgpdBD
XHUzfiFBd+HQLt5Tw5vHH0A=
=KWIZ
-----END PGP SIGNATURE-----
--

[ message continues ]

Lets get Kees involved. He developed the patch set for Hardy. I would
hope that if CONFIG_SECURITY_APPARMOR=n then the source would default to
its normal state.

rtg
-- 
Tim Gardner tim.gardner@ubuntu.com
--

[ message continues ]

Hi,


I can't claim to have developed the patches, only helping coordinate
their merging into Ubuntu.  John Johansen is the real person we should
check with -- he did all the heavy lifting -- now added to discussion.
(Hi John!)

-Kees

-- 
Kees Cook
Ubuntu Security Team
--

[ message continues ]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1


remove_suid() isn't the only change AppArmor makes to the VFS interface.
It's pretty invasive and requires that dentries are passed with a
companion vfsmount in most cases. Putting #ifdefs around all that code
would make the problem worse, not better.

- -Jeff

- --
Jeff Mahoney
SUSE Labs
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.4-svn0 (GNU/Linux)
Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org

iD8DBQFIGiOrLPWxlyuTD7IRAh3jAKCFCrBa30G5WDwmJHI+Yb4fNAfu2QCfTUmq
Q6Sf0MVug2X0ywRcSrGi4eY=
=QwF9
-----END PGP SIGNATURE-----
--

[ message continues ]

An alternative approach, and IMHO better suited, is to:

	make -C ${kdir} all I_HAZ_AN_APPARMOR=1

with this Makefile

	ifneq (${I_HAZ_AN_APPARMOR},)
	EXTRA_CFLAGS += -DHAZ_APPARMOR
	endif

This works very well for kmp-rpms, which are tied to a specific
distro, sometimes kernel, anyway.
--

[ message continues ]

This is better than the current situation (oops without any clues), but I'd 
prefer that people not have to know what apparmor is or if they have it.  
(This isn't a knock on apparmor, I'd just rather take care of it 
automagically).

-chris
--

[ message continues ]

I guess iff people have a clue just what btrfs is and what it is good for
and why one would need it, I guess they also know of Apparmor.
If not, well, I hope you mentioned it in the INSTALL file!

Well you could go down the conftest.sh route, but I dislike that
approach because such a Makefile system tries to be smarter than me;
and that often breaks because developers made a mess out of the
remaining Makefile and before long, it broke on odd, but
"standards-conforming", O= builds. (Fun stories with nvidia.)
--

[ message continues ]

^

If it oopses, then you probably also get a compile-time warning on
that remove_suid line. And in that case, you can catch it with at least 
a compile-time typecheck so as to not make the user head straight into 
an oops, is not it?
--

[ message continues ]

Chris,

Make is not my forte, but here is a working test to see if apparmor
exists in Ubuntu 8.04.
Maybe have make apply a patch to the btrfs source if this test
succeeds? Does this work in SUSE?

http://www.digitalprognosis.com/opensource/patches/btrfs/lame_apparmor_test_for_btrfs....

The symlink from /lib/modules/`uname -r`/build ->
/path/to/kernel/headers/ doesn't exist on CentOS 5.
Even though it is a hack, is this or something like it usable? Or is
this the completely wrong direction?

-- 
Jeff Schroeder

Don't drink and derive, alcohol and analysis don't mix.
http://www.digitalprognosis.com
--

[ message continues ]

Woah, you rely on autoconf.h. Uh no thanks, let the build system handle it.

# -*- Makefile -*-

btrfs-objs := ...
obj-m += btrfs.o and-so-on.o

ifneq (${CONFIG_SECURITY_APPARMOR},)
EXTRA_CFLAGS += -DI_HAZ_AN_APPARMOR
endif

all:
	${MAKE} -C ${kdir} M=$PWD all;


Best of all, you can override that from the command line too...

	make CONFIG_SECURITY_APPARMOR=y

(and if you don't, it takes its value from the appropriate .config,
all without you having to care about autoconf.h)
--

[ message continues ]

On Friday 02 May 2008, Jeff Schroeder wrote:


Thanks, but this uses CONFIG_SECURITY_APPARMOR which isn't enough to tell if 
the kernel has the patch.  Lets go back to Jeff's suse patch:

/*
 * Even if AppArmor isn't enabled, it still has different prototypes.
 * Add more distro/version pairs here to declare which has AppArmor applied.
 */
#if defined(CONFIG_SUSE_KERNEL)
# if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22)
# define REMOVE_SUID_PATH 1
# endif
#endif

Could someone from Ubuntu please suggest a replacement for CONFIG_SUSE_KERNEL 
and KERNEL_VERSION(2,6,22) that would correspond with ubuntu kernels shipped 
with apparmor?  We don't need some define from the apparmor patch, just a 
global flag that says it comes from ubuntu is enough.

-chris
--

[ message continues ]

Do we really need to support kernels compiled with the apparmour patch
applied but not enabled?  That would be a custom kernel build, and I get
the impression that people Just Don't Do That -- if they want a newer
kernel, they fetch one from kernel.org.  Maybe I'm wrong though.

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."
--

[ message continues ]

Yeah, if there's no better test I'll just use the one for the apparmor config 
(and stop spamming l-k with this btrfs specific stuff).

-chris


--

[ message continues ]

I think so too. Corollary: if there is a distro that has apparmor
patched into its kernel, then there is [hopefully] a suitable rpm
nearby.
--

[ message continues ]

To the best of my knowledge, the AppArmor patches are arch and flavour
independent. If CONFIG_SECURITY_APPARMOR exists, then the AA code is
compiled. This is certainly the case for Hardy. Neither Kees or myself
are aware of any reason why it won't also hold true for Intrepid.

rtg
-- 
Tim Gardner timg@tpi.com www.tpi.com
OR 503-601-0234 x102 MT 406-443-5357
--

[ message continues ]

I ended up using the CONFIG_SECURITY_APPARMOR test because the other test 
suggested here sounded like something that might eventually not be very 
ubuntu specific (instead of the nice a plain CONFIG_SUSE_KERNEL).

Thanks to everyone for the hints, if someone could please test:

http://btrfs.wiki.kernel.org/index.php/Hot_Fixes

I'd be grateful.

-chris
--

[ message continues ]