xfs: track usage statistics of online fsck
Track the usage, outcomes, and run times of the online fsck code, and report these values via debugfs. The columns in the file are: * scrubber name * number of scrub invocations * clean objects found * corruptions found * optimizations found * cross referencing failures * inconsistencies found during cross referencing * incomplete scrubs * warnings * number of time scrub had to retry * cumulative amount of time spent scrubbing (microseconds) * number of repair inovcations * successfully repaired objects * cumuluative amount of time spent repairing (microseconds) Signed-off-by:Darrick J. Wong <djwong@kernel.org> Reviewed-by: