Hello,

On Wed, Aug 21, 2013 at 1:06 AM, NeilBrown [off-list ref] wrote:

On Tue, 20 Aug 2013 16:08:47 +0200 Francis Moreau [off-list ref]
wrote:

quoted

hi,

It looks like a process wait uninterruptibly when it tries to access
an array which is not running yet.

Furthermore once the process is waiting, I can't start/stop the array anymore.

So I need to reboot my system and be sure next time that any processes
don't try to access a not yet running array.

Is that expected ?

No.

To be able to say more I would need lots more details.
What is the exact state of the array (cat /proc/mdstat ;mdadm -D ...)
Where is the process waiting (cat /proc/PID/stack)
What sort of "access"
How did the array get to the "not running yet" state?
Any kernel messages?
Anything else that might be relevant.

please find some details below:

# uname -r
3.9.5-301.fc19.x86_64

# mdadm --version
mdadm - v3.2.6 - 25th October 2012

# mdadm -I /dev/sda
mdadm: container /dev/md/ddf0 now has 1 device
mdadm: /dev/md/126 assembled with 1 device but not started

# cat /proc/mdstat
Personalities : [raid1]
md126 : inactive sda[0]
      8355840 blocks super external:/md127/0

md127 : inactive sda[0](S)
      32768 blocks super external:ddf

unused devices: <none>

# mdadm -R /dev/md126
mdadm: started /dev/md126

# cat /proc/mdstat
Personalities : [raid1]
md126 : active raid1 sda[0]
      8355840 blocks super external:/md127/0 [2/1] [U_]

md127 : inactive sda[0](S)
      32768 blocks super external:ddf

unused devices: <none>

# mount /dev/md126p3 /mnt
<stucks>

# ps aux | grep mount
root      1543  0.1  0.1 123404  1324 tty1     D+   09:43   0:00 mount
/dev/md126p3 /mnt

# cat /proc/1543/stack
[<ffffffff814ce285>] md_write_start+0xb5/0x1a0
[<ffffffffa0222b76>] make_request+0x46/0xc30 [raid1]
[<ffffffff814c4403>] md_make_request+0xd3/0x230
[<ffffffff812cdee2>] generic_make_request+0xc2/0x110
[<ffffffff812cdfa3>] submit_bio+0x73/0x160
[<ffffffff811ca544>] submit_bh+0x114/0x1e0
[<ffffffff811cb263>] __sync_dirty_buffer+0x53/0xe0
[<ffffffff811cb303>] sync_dirty_buffer+0x13/0x20
[<ffffffff8123dd38>] ext4_commit_super+0x198/0x230
[<ffffffff81240015>] ext4_setup_super+0x125/0x1a0
[<ffffffff8124353e>] ext4_fill_super+0x265e/0x2dc0
[<ffffffff8119cce5>] mount_bdev+0x1b5/0x1f0
[<ffffffff81232d35>] ext4_mount+0x15/0x20
[<ffffffff8119d5e9>] mount_fs+0x39/0x1b0
[<ffffffff811b679f>] vfs_kern_mount+0x5f/0xf0
[<ffffffff811b8a6e>] do_mount+0x23e/0xa20
[<ffffffff811b92d3>] sys_mount+0x83/0xc0
[<ffffffff8164e799>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff

# mdadm -D /dev/md126
/dev/md126:
      Container : /dev/md/ddf0, member 0
     Raid Level : raid1
     Array Size : 8355840 (7.97 GiB 8.56 GB)
  Used Dev Size : 8355840 (7.97 GiB 8.56 GB)
   Raid Devices : 2
  Total Devices : 1

          State : active, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 0
  Spare Devices : 0

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       0        0        1      removed

# mdadm -D /dev/md127
/dev/md127:
        Version : ddf
     Raid Level : container
  Total Devices : 1

Working Devices : 1

  Member Arrays : /dev/md/126

    Number   Major   Minor   RaidDevice

       0       8        0        -        /dev/sda

# mdadm -R /dev/md126
mdadm: failed to run array /dev/md126: Device or resource busy


Thanks
-- 
Francis