On 08/24/2017 09:03 AM, Omar Sandoval wrote: > From: Omar Sandoval <[email protected]> > > This is a different approach from the first attempt in f2c6df7dbf9a > ("loop: support 4k physical blocksize"). Rather than extending > LOOP_{GET,SET}_STATUS, add a separate ioctl just for setting the block > size. > > Signed-off-by: Omar Sandoval <[email protected]> > --- > drivers/block/loop.c | 24 ++++++++++++++++++++++++ > include/uapi/linux/loop.h | 1 + > 2 files changed, 25 insertions(+) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index 1a5b4ecf54ec..6b1d932028e3 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -1047,6 +1047,7 @@ static int loop_clr_fd(struct loop_device *lo) > memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE); > memset(lo->lo_crypt_name, 0, LO_NAME_SIZE); > memset(lo->lo_file_name, 0, LO_NAME_SIZE); > + blk_queue_logical_block_size(lo->lo_queue, 512); > if (bdev) { > bdput(bdev); > invalidate_bdev(bdev); > @@ -1330,6 +1331,24 @@ static int loop_set_dio(struct loop_device *lo, > unsigned long arg) > return error; > } > > +static int loop_set_block_size(struct loop_device *lo, unsigned long arg) > +{ > + if (lo->lo_state != Lo_bound) > + return -ENXIO; > + > + if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg)) > + return -EINVAL; > + > + blk_mq_freeze_queue(lo->lo_queue); > + > + blk_queue_logical_block_size(lo->lo_queue, arg); > + loop_update_dio(lo); > + > + blk_mq_unfreeze_queue(lo->lo_queue); > + > + return 0; > +} > + > static int lo_ioctl(struct block_device *bdev, fmode_t mode, > unsigned int cmd, unsigned long arg) > { > @@ -1378,6 +1397,11 @@ static int lo_ioctl(struct block_device *bdev, fmode_t > mode, > if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) > err = loop_set_dio(lo, arg); > break; > + case LOOP_SET_BLOCK_SIZE: > + err = -EPERM; > + if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) > + err = loop_set_block_size(lo, arg); > + break; > default: > err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; > } > diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h > index c8125ec1f4f2..23158dbe2424 100644 > --- a/include/uapi/linux/loop.h > +++ b/include/uapi/linux/loop.h > @@ -88,6 +88,7 @@ struct loop_info64 { > #define LOOP_CHANGE_FD 0x4C06 > #define LOOP_SET_CAPACITY 0x4C07 > #define LOOP_SET_DIRECT_IO 0x4C08 > +#define LOOP_SET_BLOCK_SIZE 0x4C09 > > /* /dev/loop-control interface */ > #define LOOP_CTL_ADD 0x4C80 > Hmm.
If the losetup / util-linux maintainers are on board with this, okay. Reviewed-by: Hannes Reinecke <[email protected]> Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
