quota: clear speculative delalloc when checking quota usage

Occasionally speculative preallocation kicks in when writing files
to a filesystem under test.  These preallocations consume quota and
/usually/ aren't around after we drop_caches, but there's nothing to
guarantee that they actually have, so the quota reports will be
different before and after the fs remount, causing sporadic test
failures in generic/{23[123],270}.

We now have xfs_spaceman which can instruct XFS to forcibly remove
the speculative preallocations.  This fixes the sporadic failures,
at least for XFS.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

common/config

@@ -149,6 +149,7 @@ export XFS_LOGPRINT_PROG="`set_prog_path xfs_logprint`"
 export XFS_REPAIR_PROG="`set_prog_path xfs_repair`"
 export XFS_DB_PROG="`set_prog_path xfs_db`"
 export XFS_GROWFS_PROG=`set_prog_path xfs_growfs`
+export XFS_SPACEMAN_PROG="`set_prog_path xfs_spaceman`"
 export XFS_SCRUB_PROG="`set_prog_path xfs_scrub`"
 export XFS_PARALLEL_REPAIR_PROG="`set_prog_path xfs_prepair`"
 export XFS_PARALLEL_REPAIR64_PROG="`set_prog_path xfs_prepair64`"

common/quota

@@ -267,6 +267,12 @@ _check_quota_usage()
 		VFS_QUOTA=1
 		quotaon -f -u -g $SCRATCH_MNT 2>/dev/null
 		;;
+	xfs)
+		# Clear out speculative preallocations to eliminate them
+		# as a source of intermittent orig/checked differences.
+		test -x "$XFS_SPACEMAN_PROG" && \
+			"$XFS_SPACEMAN_PROG" -c 'prealloc -s' $SCRATCH_MNT
+		;;
 	*)
 		;;
 	esac