COWed devices can't handle more than 32 (64 on x86_64) sectors in one request
due to the size of the bitmap being carried around in the io_thread_req.
Enforce that by telling the block layer not to put too many sectors in
requests to COWed devices.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Jeff Dike
37ed1c7082