On Friday 19 March 2004 2:30 pm, Yaroslav Popovitch wrote: > if option <sector count> is equal to 0, then dmsetup > reports about error, but still creates device. > > Useful output: > [root@deimos yp]# echo 0 0 crypt aes-plain > 4e1243bd22c66e76c2ba9eddc1f91394 0 /dev/loop0 0|dmsetup create volume1 > device-mapper ioctl cmd 9 failed: Invalid argument > Command failed > [root@deimos yp]# echo $? > 1 > [root@deimos yp]# dmsetup ls > volume1 (254, 0) > [root@deimos yp]# dmsetup mknodes > [root@deimos yp]# lsmod /dev/mapper/ > control volume1 > > Configuration: > device-mapper-1.00.08 > Linux kernel 2.6.4 > > Cheers,YP What actually happened here is that you created a device called "volume1", and then tried to load a table with a zero-length target, which isn't allowed. The creation of the device worked as expected, and it's perfectly legitimate to have a device without a table (you just can't perform any I/O on that device). The confusing thing here is that dmsetup allows you to combine these two steps (creating the device and loading the table) into one. Dmsetup also allows you to create the device without specifying the table, and you can later use "dmsetup load" to load a table into that device, and "dmsetup resume" to activate that table. The "combined" version is a carry-over from the way the version 1 ioctl interface created devices. So what you're really looking for here is that when you use "dmsetup create" in the create-with-table mode, dmsetup should remove the device if the load-table portion fails. -- Kevin Corry kevcorry@xxxxxxxxxx http://evms.sourceforge.net/
