Miscellaneous device-mapper fixes, cleanups and performance improvements.

Of particular note:
- Disable broken WRITE SAME support in all targets except linear and striped.
  Use it when kcopyd is zeroing blocks.
- Remove several mempools from targets by moving the data into the bio's new
  front_pad area(which dm calls 'per_bio_data').
- Fix a race in thin provisioning if discards are misused.
- Prevent userspace from interfering with the ioctl parameters and
  use kmalloc for the data buffer if it's small instead of vmalloc.
- Throttle some annoying error messages when I/O fails.
dm stripe: add WRITE SAME support

Rename stripe_map_discard to stripe_map_range and reuse it for WRITE
SAME bio processing.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 file changed