On Fri, Mar 4, 2016 at 4:56 PM, Darrick J. Wong [off-list ref] wrote:

+       /* Only punch if the device can do zeroing discard. */
+       if ((mode & FALLOC_FL_PUNCH_HOLE) &&
+           (!blk_queue_discard(q) || !q->limits.discard_zeroes_data))
+               return -EOPNOTSUPP;

I'm ok with this, but suspect that some users would prefer to just
turn this into ZERO_RANGE silently.

Comments from people who would be expected to use this?

            Linus