On Thu, Jan 11, 2018 at 2:09 PM, Ilya Dryomov [off-list ref] wrote:

Hello,

I was doing some cleanup work on rbd BLKROSET handler and discovered
that we ignore partition rw/ro setting (hd_struct->policy) for pretty
much everything but straight writes.

David (CCed) has blktests patches standing by.

(Another aspect of this is that we don't enforce open(2) mode.  Tejun
took a stab at this a few years ago, but his patch had to be reverted:

  75f1dc0d076d ("block: check bdev_read_only() from blkdev_get()")
  e51900f7d38c ("block: revert block_dev read-only check")

It is a separate issue and refusing writes to read-only devices is
obviously more important, but perhaps it's time to revisit that as
well?)

v2 -> v3:
- lookup part only once; combine read-only check with existing
  should_fail_request check

v1 -> v2:
- added unlikely() per Sagi's suggestion

Thanks,

                Ilya


Ilya Dryomov (2):
  block: fail op_is_write() requests to read-only partitions
  block: add bdev_read_only() checks to common helpers

 block/blk-core.c | 56 ++++++++++++++++++++++++++++++++++++++------------------
 block/blk-lib.c  | 12 ++++++++++++
 2 files changed, 50 insertions(+), 18 deletions(-)

Jens, could you please pick these up for 4.16?

Thanks,

                Ilya