[LTP] [PATCH] syscalls/ioctl_loop05: Get the logic_block_size dynamically

[Jan Stancek]

----- Original Message -----
> >>> Would BLKSSZGET work? It returns bdev_logical_block_size().
> >>
> >> But it needs a blockdev, in user space, we can specify bdev, but how can
> >> we
> >> figure out this inode->i_sb->s_bdev block dev.
> > 
> > Isn't that the block device "test.img" is on?
> Do you mean the test.img belong to some block dev, such as /dev/sda1 or
> our mounted block_dev? If so, I think it is.

The former. Say if test.img is in /tmp, then I'd assume "s_bdev" is
/dev/mapper/rhel-root (/dev/dm-0)

$ df -T /tmp/test.img
Filesystem            Type 1K-blocks     Used Available Use% Mounted on
/dev/mapper/rhel-root xfs   66789516 33211340  33578176  50% /