[RFC PATCH 0/2] a couple of readonly handling fixups

The BUG_ON(mddev->ro == 1) in md_write_start can be triggered under two
circumstances in recent kernels.  One was reported by Justin Maggard:

1) Create an md array with >= 1 disk
2) Start a task writing to the array ("dd if=/dev/zero of=/dev/md0
bs=1M count=10000 &" does the trick for me)
3) Force an improper reboot with reboot -fn

...the other was discovered while investigating this issue.

1) Set a raid5 readyonly with mdadm
2) Set the array writable with blockdev
3) Attempt to write to the array

---

Dan Williams (2):
      Revert "Restore force switch of md array to readonly at reboot time."
      md: set mddev readonly flag on blkdev BLKROSET ioctl

 drivers/md/md.c |   35 ++++++++++++++++++++++++++++++-----
 1 files changed, 30 insertions(+), 5 deletions(-)