Bug 38111 - RAID funkiness (md: bug in file md.c...)
RAID funkiness (md: bug in file md.c...)
Product: Red Hat Raw Hide
Classification: Retired
Component: kernel (Show other bugs)
alpha Linux
low Severity high
: ---
: ---
Assigned To: Arjan van de Ven
Brock Organ
Depends On:
  Show dependency treegraph
Reported: 2001-04-27 17:37 EDT by Elliot Lee
Modified: 2005-10-31 17:00 EST (History)
2 users (show)

See Also:
Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2002-06-13 08:29:49 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
kernel-smp-2.4.3-2.14.4 boot log on ostrich-deluxe.labs.redhat.com (25.33 KB, text/plain)
2001-04-27 17:41 EDT, Elliot Lee
no flags Details
ostrich-deluxe.labs.redhat.com:/etc/raidtab (534 bytes, text/plain)
2001-04-27 17:43 EDT, Elliot Lee
no flags Details
The utility I used to solve the problem, for historical interest only (3.84 KB, application/x-tar)
2002-06-13 08:29 EDT, Elliot Lee
no flags Details

  None (edit)
Description Elliot Lee 2001-04-27 17:37:56 EDT
Things get "weird" when trying to boot the wolverine-alpha2 kernel on this

A relevant detail may be that the 2.2 kernel sometimes has to spin /dev/sdg
up during boot. Otherwise, everything seems to function normally under

I will attach the 2.4 boot log and the raidtab file. Please let me know
what other information might be useful.
Comment 1 Elliot Lee 2001-04-27 17:41:55 EDT
Created attachment 16689 [details]
kernel-smp-2.4.3-2.14.4 boot log on ostrich-deluxe.labs.redhat.com
Comment 2 Elliot Lee 2001-04-27 17:43:11 EDT
Created attachment 16690 [details]
Comment 3 Elliot Lee 2001-06-29 14:12:51 EDT
Going to add Bryce to the Cc: list just because he claimed it had been fixed,
and it still hasn't. :)
Comment 4 Phil Copeland 2001-06-29 14:37:08 EDT
<Grumble> I can't fix what I can't replicate
As and when I can, I'll retackle this problem


Comment 5 Elliot Lee 2001-07-02 18:11:54 EDT
Linux/Alpha 2.2.x: sizeof(mdp_super_t) == 4104, offsetof(mdp_super_t,
gstate_reserved) == 168

Linux/Alpha 2.4.x: sizeof(mdp_super_t) == 4096, offsetof(mdp_super_t,
gstate_reserved) == 164.

It looks like someone seriously broke on-disk backwards compat during the
attempt to whittle mdp_super_t down to a dividable-by-1024 size.

Ingo added to Cc's because he probably knows what is going on.
Comment 6 Elliot Lee 2001-07-02 20:01:10 EDT
Changing priority to 'low' because I hacked a util to do the conversion.
Comment 7 alvin 2002-04-23 12:18:56 EDT
This ends up being an alignment bug.
The event counter was a 64 bit item and as such was 64bit aligned so there was a
32bit pad before the counter in the 2.2 version of the structure.
the 2.4 version of the structure has 2 32 bit items as the event counter. These
are now 32bit aligned and the padding has gone away.

I have a small patch to check for this condition and repare the raidtable but I
am not sure if it is truly ok to do this.
Comment 8 Elliot Lee 2002-04-23 12:29:59 EDT
I can confirm your description because I found the same thing out when creating
the conversion utility. The only question is whether the kernel dudes will ever
do something about it :)
Comment 9 Phil Copeland 2002-04-23 14:32:19 EDT
/me twiddles thumbs,...

Files, patchs?


Comment 10 Elliot Lee 2002-06-13 08:29:43 EDT
Created attachment 60825 [details]
The utility I used to solve the problem, for historical interest only
Comment 11 Elliot Lee 2002-06-13 08:30:55 EDT
If you're not gonna fix it, say so...

Note You need to log in before you can comment on or make changes to this bug.