On 05/17/2012 03:52, Liu Bo wrote:

On 05/17/2012 12:50 AM, Stefan Behrens wrote:

quoted

The device statistics are written into the device tree with each
transaction commit. Only modified statistics are written.
When a filesystem is mounted, the device statistics for each involved
device are read from the device tree and used to initialize the
counters.

Hi Stefan,

Just scaned the patch for a while and got a question:

Adding a new key type usually means changing the disk format,
so have you done something for this?

Hi Liu,

New tree entries with new keys are added to the device tree. Old kernels 
do not search for these keys and therefore ignore them. New kernels 
(with this patch) search for these keys and read and write them, or 
create them when required. That works fine.