Re: mdadm 3.3 fails to kick out non fresh disk

[NeilBrown <neilb@suse.de>]

[-- Attachment #1: Type: text/plain, Size: 2029 bytes --]

On Fri, 13 Sep 2013 15:22:20 +0200 Francis Moreau <francis.moro@gmail.com>
wrote:

> Hi Neil,
> 
> I'm probably doing something wrong since it's a pretty critical bug
> but can't see what.
> 
> I'm creating a RAID1 array with 1.2 metadata. After that I stop the
> array, and restart the array with only one disk. I write random data
> on the array and then stop it again:
> 
> # mkfs.ext4 /dev/md125
> # mdadm --stop /dev/md125
> # mdadm -IRs /dev/loop0
> # mount /dev/md125 /mnt/
> # date >/mnt/foo
> # umount /mnt
> # mdadm --stop /dev/md125
> 
> Finally I restart the array with the 2 disks (one disk is outdated)
> and mdadm happily activates the array without error. Note that I add
> the outdated disk first in that case:
> 
> # mdadm -IRs /dev/loop1
> mdadm: /dev/loop1 attached to /dev/md/array1, which has been started.
> # mdadm -IRs /dev/loop0
> mdadm: /dev/loop0 attached to /dev/md/array1 which is already active.

That's a worry.  I'm not sure how to fix it.

I would probably suggest you don't use "-IR" to add devices.  That would make
it a lot less likely to happen.


> # cat /proc/mdstat
> Personalities : [raid1]
> md125 : active raid1 loop0[0] loop1[1]
>       117056 blocks super 1.2 [2/2] [UU]
> # mount /dev/md125 /mnt
> # ls /mnt/
> [  457.321771] EXT4-fs error (device md125): ext4_lookup:1047: inode
> #2: comm ls: deleted inode referenced: 12
> ls: cannot access /mnt/1: Input/output error
> 
> If I add the outdated disk last I got this:
> # mdadm -IRs /dev/loop0
> mdadm: /dev/loop0 attached to /dev/md/array1, which has been started.
> # mdadm -IRs /dev/loop1
> mdadm: can only add /dev/loop1 to /dev/md/array1 as a spare, and
> force-spare is not set.
> mdadm: failed to add /dev/loop1 to existing array /dev/md/array1:
> Invalid argument.
> 
> which didn't tell me the reason why loop1 must be a spare.

It  must be a spare because it is out of date.


NeilBrown

> 
> Is this expected ? If so could you enlight me ?
> 
> Thanks


[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 828 bytes --]