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: Dave Chinner <dchinner@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig
index 152348b4dece..c9d653168ad0 100644
--- a/fs/xfs/Kconfig
+++ b/fs/xfs/Kconfig
@@ -143,6 +143,23 @@ config XFS_ONLINE_SCRUB
 
 	  If unsure, say N.
 
+config XFS_ONLINE_SCRUB_STATS
+	bool "XFS online metadata check usage data collection"
+	default y
+	depends on XFS_ONLINE_SCRUB
+	select FS_DEBUG
+	help
+	  If you say Y here, the kernel will gather usage data about
+	  the online metadata check subsystem.  This includes the number
+	  of invocations, the outcomes, and the results of repairs, if any.
+	  This may slow down scrub slightly due to the use of high precision
+	  timers and the need to merge per-invocation information into the
+	  filesystem counters.
+
+	  Usage data are collected in /sys/kernel/debug/xfs/scrub.
+
+	  If unsure, say N.
+
 config XFS_ONLINE_REPAIR
 	bool "XFS online metadata repair support"
 	default n