On Fri, May 16, 2014 at 02:12:46PM -0400, Brian Foster wrote: > Create sysfs attributes to export the current runtime state of the log > to userspace. Note that the filesystem should be frozen for best > accuracy/consistency when reading these values, but is not required. > This is for testing and debug purposes only. > > Create the following per-mount attributes: log_head_lsn, log_tail_lsn, > reserve_head_lsn and write_head_lsn. These represent the physical log Reserve and write heads are not log sequence numbers (LSNs). A LSN is a cycle:block count tuple, while a grant head is a cycle:byte count tuple.... Calling the reserve_grant_head/write_grant_head would make more sense, I think, as would splitting them into cycle/byte output pairs. Splitting them make sense because if we increase the log size beyond 2GB we're going to need a different in-memory representation for the grant heads (i.e. need more than 32 bits for byte count), so we should probably handle that up front in the sysfs API... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
