-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/07/2011 03:57 PM, Stefan Seyfried wrote:

On Thu, 7 Apr 2011 20:57:12 +0200 Jan Kara wrote:

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so that ext4 driver is used for ext2 filesystem and see whether something breaks or not.

Do people have any opinion on this?

Just make sure that no filesystem is converted by accident (not sure if that could happen with the ext4 driver).

tune2fs is AFAIK the only way to enable incompatible features (like a journal or extents) on an ext[234] file system. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ iEYEARECAAYFAk2eIVUACgkQLPWxlyuTD7KzGQCbBvl0vZssZPp2FE1j6J1smIGO ydAAoKVw0hqBafFeEil+yINulgfWwqlB =SncB -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/07/2011 04:04 PM, Brian K. White wrote:

On 4/7/2011 2:57 PM, Jan Kara wrote:

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Hello,

we are figuring out upstream how to eventually get rid of maintaing three code bases of ext2, ext3, and ext4 in parallel. These days ext4 kernel driver is able to handle both ext2 and ext3 filesystems in a backward compatible manner - i.e., you can mount, access, modify the filesystem with ext4 driver and then still be able to use it with the old ext2 driver. So I'd think that we could try changing config of our kernel in Factory so that ext4 driver is used for ext2 filesystem and see whether something breaks or not.

Do people have any opinion on this?

Honza

Is ext4 driver as fast, stable, small/simple for embedded, matured for over 10 years as ext2 driver ? Everything else might be green but that last is hard to address other than by "Feel free to use old kernel and old anything else that doesn't work on that old kernel.".

Also more than one implementation of a core thing is not always bad. It allows a user to discover that a problem seen in one turns out not to exist in the other.

This actually ends up not working out that well. What ends up happening is that bugs are fixed in the version that is most current, now ext4 but this happened with ext3 as well, and perhaps not in older versions. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ iEYEARECAAYFAk2eIa4ACgkQLPWxlyuTD7JXfgCfezb6BVgaaCg0aswFY0brqM3L a74AmgNhDCQtjI9gMtJdCRdCEh4AMRNN =6zm1 -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 04/07/2011 11:15 PM, doiggl@velocitynet.com.au wrote:

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Hello,

we are figuring out upstream how to eventually get rid of maintaing

On Thu, 7 Apr 2011 20:57:12 +0200, Jan Kara wrote: three

...

code bases of ext2, ext3, and ext4 in parallel. These days ext4 kernel driver is able to handle both ext2 and ext3 filesystems in a backward compatible manner - i.e., you can mount, access, modify the filesystem with ext4 driver and then still be able to use it with the old ext2 driver. So I'd think that we could try changing config of our kernel in Factory so that ext4 driver is used for ext2 filesystem and see whether something breaks or not.

Do people have any opinion on this?

Honza -- Jan Kara SUSE Labs, CR

Hello Some thoughts on this If filesystem is not in use e.g overnight /out of business hours - tar existing files up to somewhere else provided there is enough free target space - Reformat {ext2, ext3}partition to ext4 - Restore files to the reformatted partition - do the smaller partitions first [df -h] will get the sizes of partitions - unsure if dir/file permissions are preserved though. - Prehaps use cron to assist to do the job

This is actually unnecessary unless you want to do things like use extents on existing files. The format is forward-compatible so you can use tune2fs to enable the features added by newer versions. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ iEYEARECAAYFAk2jEL4ACgkQLPWxlyuTD7L/kgCfSTvh26xJZULEtQdzc/jSMDgs q4kAniEK0bb885cxv7Vk9YSZQNs1pF6u =GXDe -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org

On Thursday 07 April 2011 08:57:12 pm Jan Kara wrote:

...

Hello,

we are figuring out upstream how to eventually get rid of maintaing three code bases of ext2, ext3, and ext4 in parallel. These days ext4 kernel driver is able to handle both ext2 and ext3 filesystems in a backward compatible manner - i.e., you can mount, access, modify the filesystem with ext4 driver and then still be able to use it with the old ext2 driver. So I'd think that we could try changing config of our kernel in Factory so that ext4 driver is used for ext2 filesystem and see whether something breaks or not.

Do people have any opinion on this?

Wouldn't it be a safest path to replace the use cases of ext2 with ext_3_? It's way more mature than ext4, and presumably people have already been using ext3 to mount ext2 partitions for years. There's a problem with ext3 replacing ext2 as ext3 adds journaling which adds visible performance overhead. I suppose people who had not migrated from ext2 to ext3 by now either care about the performance difference or just don't care about anything all :). In both cases ext4 should be OK with

As you didn't mention a plan to drop the ext3 driver, I'd use it for ext2. IMHO it only makes sense to use the ext4 driver for ext2 partitions if we plan to drop the ext2 _and_ ext3 drivers, and use the ext4 driver for all three partition types. Well, there are plans for dropping ext3 as well. I just want to do it step by step. And ext3 is used by *much* more users than ext2 these days so

Hi Jean, On Fri 08-04-11 19:36:56, Jean Delvare wrote: them. I agree that ext3 is more mature than ext4 but by now ext4 is pretty stable as well so I wouldn't be afraid to offer it to openSUSE users as a replacement. In fact, ext2 codebase bitrots slowly because noone really cares about it so migrating to ext4 is not that bad idea from stability POV either. that's why I want to be extra careful there... Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org

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On Fri 08-04-11 19:36:56, Jean Delvare wrote:

...

On Thursday 07 April 2011 08:57:12 pm Jan Kara wrote:

...

Hello,

we are figuring out upstream how to eventually get rid of maintaing three code bases of ext2, ext3, and ext4 in parallel. These days ext4 kernel driver is able to handle both ext2 and ext3 filesystems in a backward compatible manner - i.e., you can mount, access, modify the filesystem with ext4 driver and then still be able to use it with the old ext2 driver. So I'd think that we could try changing config of our kernel in Factory so that ext4 driver is used for ext2 filesystem and see whether something breaks or not.

Do people have any opinion on this?

Wouldn't it be a safest path to replace the use cases of ext2 with ext_3_? It's way more mature than ext4, and presumably people have already been using ext3 to mount ext2 partitions for years.

...

There's a problem with ext3 replacing ext2 as ext3 adds journaling which adds visible performance overhead. I suppose people who had not migrated from ext2 to ext3 by now either care about the performance difference or just don't care about anything all :). In both cases ext4 should be

Or are using flash cards :-). Oh yeah, that's a good point (for other readers, some flash cards tend to have "interesting" properties invalidating assumptions any sane journalling filesystem has about the behavior of underlying device. Thus crashing in

On Fri 15-04-11 18:29:49, Pavel Machek wrote: the middle of write is going to corrupt filesystem on these regardless of journalling). But ext4 in nojournal mode should be fine in this case either :) Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org