On 04/06/2017 02:03 PM, Ming Lei wrote: > On Thu, Apr 06, 2017 at 04:43:18PM +0800, Ming Lei wrote: >> On Thu, Apr 06, 2017 at 01:19:45AM -0700, Omar Sandoval wrote: >>> From: Omar Sandoval <osandov@xxxxxx> >>> >>> The request queue created when we create a loop device has the default >>> logical block size of 512. When we associate the device with an fd, we >>> set the block size on the block_device but don't update the logical >>> block size of the request_queue. This makes it impossibe to use direct >>> I/O with a backing file on a device with a block size >512, as the >>> following check in __loop_update_dio() fails: >>> >>> sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev); >>> if (queue_logical_block_size(lo->lo_queue) >= sb_bsize && >>> ... >>> >>> Fix it by updating the logical block size when we set the fd. >>> >>> Signed-off-by: Omar Sandoval <osandov@xxxxxx> >>> --- >>> drivers/block/loop.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/drivers/block/loop.c b/drivers/block/loop.c >>> index cc981f34e017..1bb22903ad1a 100644 >>> --- a/drivers/block/loop.c >>> +++ b/drivers/block/loop.c >>> @@ -941,6 +941,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, >>> /* let user-space know about the new size */ >>> kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE); >>> >>> + blk_queue_logical_block_size(lo->lo_queue, lo_blocksize); >>> set_blocksize(bdev, lo_blocksize); >>> >>> lo->lo_state = Lo_bound; >> >> Looks fine! >> >> Reviewed-by: Ming Lei <minlei@xxxxxxxxxx> > > Turns out I am wrong, and we can't change logical block size in this way > because we need to support 512 byte sector filesystem image on backing > device with bigger sector size. > > And we don't support dio in this situation yet, but Hannes Reinecke's > patch might help this case. So I have to recall the reviewed-by. > Yes, please! I've been waiting for it far too long. Should I repost them? Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@xxxxxxx +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)
