[dm-devel] device mapper and resizing devices

[Andy <genanr emsphone com>]

I am using dm-multipath on non-partitioned (xfs) devices on a SAN.  If I
resize the device, and rescan my path devices (i.e rescan /dev/sda,
/dev/sdb, /dev/sdc,/dev/sdd (all the same path)) the kernel sees the new
size of the individual devices, but the /sys/block/dm-0 device is still the
old size.  I believe this is the reason why I cannot grow my xfs filesystem
without doing a reboot so that the dm device will have the new size. I'd
like to avoid unmounting and rebooting to resize the device.  I haven't
played with lvm enough to feel comfortable using it.  Is there any way to
get the dm device to be the proper size, or is this a bug, or a feature that
needs further discussion?

Andy