I have implemented my own device mapper target and I am able to create a mapped device with dmsetup create command.
The problem is that the sector size for this device becomes the default 512 bytes, and I would like to change it to 4096 bytes similar to dm-verity targets.
For instance, below is the sector size for a dm-verity device, and fdisk reports 4096 bytes:
$sudo fdisk -l /dev/mapper/dmv
Disk /dev/mapper/dmv: 8 KiB, 8192 bytes, 2 sectors
Units: sectors of 1 * 4096 = 4096 bytes
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Below is the sector size for my own target, and fdisk reports 512 bytes:
sudo fdisk -l /dev/mapper/my-target
Disk /dev/mapper/my-target: 8 KiB, 8192 bytes, 16 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
How can I set the sector size for my own device mapper target? I couldn't find where this is done in libdevmapper or cryptsetup source for the dm-verity case.
Cheers!