ioctl$BTRFS_IOC_GET_SUBVOL_ROOTREF(0xffffffffffffffff, 0xd000943d, 0x0)
r0 = openat$sr(0xffffffffffffff9c, &(0x7f00000035c0), 0xe8b02, 0x0)
ioctl$SG_IO(0xffffffffffffffff, 0x2285, 0x0)
ioctl$SG_IO(r0, 0x127f, 0x0)