Bug 270772 – raid=part kernel parameter is ignored.

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Edoardo Liverani 2009-05-21 22:16:44 UTC]

Summary:
The kernel command line option raid=part (or raid=partitionable) is ignored in kernel 2.6.28-r5 (gentoo-sources-2.6.28-r5), while it worked with kernel 2.6.24-gentoo-r8. (I don't know from which version it happens)

The partition table in raid devices is not scanned after raid-autodetect during boot, cause booting impossible if the root partition is in the md device.

Instead, if the scan is forced after the boot (eg. after stopping md device) with command mdadm --auto-detect, it scan the partition tables and create the correct devices.
Eg.  md_d3: p1 p2 p3 < p5 p6 p7 >

In kernel 2.6.24-gentoo-r8 instead it worked and I could boot.

The error is reproducible doing following passages:
1.Create an md device with --auto=part, then fdisk it and create partition(s).
2.Configure the kernel with raid built-in and autodetection.
3.Boot indicating raid=part, and root=mdxpy or root=md_dxpy (or what is the array device name, as you can see with mdadm --auto-detect)
4.The kernel autodetects and start the array.
5.The kernel can't find the partition and panics.

What is expected:
The kernel scan the partition table, then mount the root partition.

The raid=part parameter is specified both in md(4) man page and in md.txt in the linux kernel documentation.

For more info: http://forums.gentoo.org/viewtopic.php?p=5742176

[Comment 1 Markos Chandras (RETIRED) 2009-05-22 09:27:19 UTC]

Hi. Thanks for reporting this

Recent kernel versions include some fixes on init/do_mounts_mb.c file

Could you please try the latest sys-kernel/gentoo-sources-2.6.29-r4 or the latest git sources ( sys-kernel/git-sources-2.6.30_rc6-r5 ) and report back your results?

Thank you

[Comment 2 Edoardo Liverani 2009-05-22 14:58:01 UTC]

Both sys-kernel/gentoo-sources-2.6.29-r4  and sys-kernel/git-sources-2.6.30_rc6-r5 works correctly.

[Comment 3 Markos Chandras (RETIRED) 2009-05-22 15:35:15 UTC]

Great. Could you please apply this patch on gentoo-sources.2.6.28-r5, compile and verify that your RAID works again? Thanks

http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.29.y.git;a=commitdiff_plain;h=ff083c8372f6312bb3a8c7f7b748920aeeb210c9

[Comment 4 Edoardo Liverani 2009-05-25 17:22:59 UTC]

This patch doesn't work, sorry.

[Comment 5 Daniel Drake (RETIRED) 2009-06-21 15:51:05 UTC]

closing as 2.6.29 is now stable