[Bug 320638] Re: hot-add/remove in mixed (IDE/SATA/USB/SD-card/...) RAIDs with device mapper on top => data corruption (bio too big device md0 (248 > 240))

[ceg]

** Also affects: mdadm
   Importance: Undecided
       Status: New

** Changed in: mdadm
       Status: New => Confirmed

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to ubiquity in Ubuntu.
https://bugs.launchpad.net/bugs/320638

Title:
  hot-add/remove in mixed (IDE/SATA/USB/SD-card/...)  RAIDs with device
  mapper on top => data corruption (bio too big device md0 (248 > 240))

Status in The Linux Kernel:
  Confirmed
Status in mdadm - Tool for managing linux software RAID arrays.:
  Confirmed
Status in “debian-installer” package in Ubuntu:
  Confirmed
Status in “linux” package in Ubuntu:
  Won't Fix
Status in “mdadm” package in Ubuntu:
  Confirmed
Status in “ubiquity” package in Ubuntu:
  New

Bug description:
  Problem: md changes max_sector setting of an already running and busy
  md device, when a (hotplugable) device is added or removed. However,
  the device mapper and filesystem layer on top of the raid can not
  (always?) cope with that.

  Observations:
  * "bio too big device mdX (248 > 240)" messages in the syslog
  * read/write errors (some dropped silently, no noticable errors reported during operation, until things like dhcpclient looses its IP etc.)

  Expected:
  Adding and removing members to running raids (hotplugging) should not change the raid device characteristics. If the new member supports only smaller max_sector values, buffer and split the data steam, until the raid device can be set up from a clean state with a more appropriate max_sector value. To avoid buffering and splitting in the future, md could save the smallest max_sector value of the known members in the superblock, and use that when setting up the raid even if that member is not present.

  Note: This is reproducible in much more common scenarios as the original reporter had (e.g. --add a USB (3.0 these days) drive to an already running SATA raid1 and grow the number of devices).
  ---

  This is on a MSI Wind U100 and I've got the following stack running:
  HDD & SD card (USB card reader) -> RAID1 -> LUKS -> LVM -> Reiser

  Whenever I remove the HDD from the Raid1
  > mdadm /dev/md0 --fail /dev/sda2
  > mdadm /dev/md0 --remove /dev/sda2)
  for powersaving reasons, I cannot run any apt related tools.

  > sudo apt-get update
  [...]
  Hit http://de.archive.ubuntu.com intrepid-updates/multiverse Sources
  Reading package lists... Error!
  E: Read error - read (5 Input/output error)
  E: The package lists or status file could not be parsed or opened.

  Taking a look at the kernel log shows (and many more above):
  > dmesg|tail
  [ 9479.330550] bio too big device md0 (248 > 240)
  [ 9479.331375] bio too big device md0 (248 > 240)
  [ 9479.332182] bio too big device md0 (248 > 240)
  [ 9611.980294] bio too big device md0 (248 > 240)
  [ 9742.929761] bio too big device md0 (248 > 240)
  [ 9852.932001] bio too big device md0 (248 > 240)
  [ 9852.935395] bio too big device md0 (248 > 240)
  [ 9852.938064] bio too big device md0 (248 > 240)
  [ 9853.081046] bio too big device md0 (248 > 240)
  [ 9853.081688] bio too big device md0 (248 > 240)

  $ sudo mdadm --detail /dev/md0
  /dev/md0:
          Version : 00.90
    Creation Time : Tue Jan 13 11:25:57 2009
       Raid Level : raid1
       Array Size : 3871552 (3.69 GiB 3.96 GB)
    Used Dev Size : 3871552 (3.69 GiB 3.96 GB)
     Raid Devices : 2
    Total Devices : 1
  Preferred Minor : 0
      Persistence : Superblock is persistent

    Intent Bitmap : Internal

      Update Time : Fri Jan 23 21:47:35 2009
            State : active, degraded
   Active Devices : 1
  Working Devices : 1
   Failed Devices : 0
    Spare Devices : 0

             UUID : 89863068:bc52a0c0:44a5346e:9d69deca (local to host m-twain)
           Events : 0.8767

      Number   Major   Minor   RaidDevice State
         0       0        0        0      removed
         1       8       17        1      active sync writemostly   /dev/sdb1

  $ sudo ubuntu-bug -p linux-meta
  dpkg-query: failed in buffer_read(fd): copy info file `/var/lib/dpkg/status': Input/output error
  dpkg-query: failed in buffer_read(fd): copy info file `/var/lib/dpkg/status': Input/output error
  [...]

  Will provide separate attachements.

To manage notifications about this bug go to:
https://bugs.launchpad.net/linux/+bug/320638/+subscriptions