block: loop: introduce ioctl command of LOOP_SET_DIRECT_IO

If loop block is mounted via 'mount -o loop', it isn't easy
to pass file descriptor opened as O_DIRECT, so this patch
introduces a new command to support direct IO for this case.

Cc: linux-api@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Ming Lei 2015-08-17 10:31:50 +08:00 committed by Jens Axboe
parent 2e5ab5f379
commit ab1cb278bc
2 changed files with 20 additions and 0 deletions

View file

@ -87,6 +87,7 @@ struct loop_info64 {
#define LOOP_GET_STATUS64 0x4C05
#define LOOP_CHANGE_FD 0x4C06
#define LOOP_SET_CAPACITY 0x4C07
#define LOOP_SET_DIRECT_IO 0x4C08
/* /dev/loop-control interface */
#define LOOP_CTL_ADD 0x4C80