On Thu, Mar 22, 2012 at 04:15:11PM +1100, Dave Chinner wrote: > From: Dave Chinner <dchinner@xxxxxxxxxx> > > There have been a few reports of this warning appearing recently: > > XFS (dm-4): xlog_space_left: head behind tail > tail_cycle = 129, tail_bytes = 20163072 > GH cycle = 129, GH bytes = 20162880 > > The common cause appears to be lots of freeze and unfreeze cycles, > and the output from the warnings indicates that we are leaking > around 8 bytes of log space per freeze/unfreeze cycle. > > When we freeze the filesystem, we write an unmount record and that > uses xlog_write directly - a special type of transaction, > effectively. What it doesn't do, however, is correctly acocunt for > the log space it uses. The unmount record writes an 8 byte structure > with a special magic number into the log, and the space this > consumes is not accounted for in the log ticket tracking the > operation. Hence we leak 8 bytes every unmount record that is > written. > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> Looks good. Reviewed-by: Ben Myers <bpm@xxxxxxx> _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
