Add test exercising the totl recompute ioctl.

Basic validation for the recompute-xattr-total ioctl through the
totl-delta-inject ioctl. Takes a few different corrective actions that
are plausible - simple drifted values, and a stray orphan totl.

The test validates that the kmod dmesg output matches what was
expected since that's our proof that repair happened, but the actual
warnings are filtered from logs during test to not fail our test
case otherwise.

Signed-off-by: Auke Kok <auke.kok@versity.com>

tests/funcs/filter.sh

@@ -171,6 +171,9 @@ t_filter_dmesg()
 	# orphan log trees reclaim is handled, not an error
 	re="$re|scoutfs .* reclaiming orphan log trees"
 
+	# recompute-xattr-total logs every corrective delta it applies
+	re="$re|scoutfs .* warning: totl recompute applying delta .*"
+
 	# fencing tests force unmounts and trigger timeouts
 	re="$re|scoutfs .* forcing unmount"
 	re="$re|scoutfs .* reconnect timed out"

tests/golden/totl-recompute

@@ -0,0 +1,23 @@
+== setup three files contributing to totl 8888.0.0
+== merge baseline into fs_root
+8888.0.0 = 42, 3
+== recompute on a clean baseline is a no-op
+8888.0.0 = 42, 3
+== inject (+128, +2) corrupts totl 8888.0.0
+8888.0.0 = 170, 5
+== recompute restores 8888.0.0
+totl recompute applying delta total=-128 count=-2 to key 12.8888.0.0.0.0 (was total=170 count=5, recomputed total=42 count=3)
+8888.0.0 = 42, 3
+== inject (-50, +1) corrupts totl 8888.0.0 again
+8888.0.0 = -8, 4
+== recompute restores 8888.0.0
+totl recompute applying delta total=50 count=-1 to key 12.8888.0.0.0.0 (was total=-8 count=4, recomputed total=42 count=3)
+8888.0.0 = 42, 3
+== recompute on an unused key is a no-op
+8888.0.0 = 42, 3
+== inject (+7, +1) at unused key 8888.1.1 then recompute clears it
+8888.0.0 = 42, 3
+8888.1.1 = 7, 1
+totl recompute applying delta total=-7 count=-1 to key 12.8888.0.1.1.0 (was total=7 count=1, recomputed total=0 count=0)
+8888.0.0 = 42, 3
+== cleanup

tests/sequence

@@ -30,6 +30,7 @@ basic-xattr-indx.sh
 quota.sh
 totl-merge-read.sh
 totl-delta-inject.sh
+totl-recompute.sh
 lock-refleak.sh
 lock-shrink-consistency.sh
 lock-shrink-read-race.sh

tests/tests/totl-recompute.sh

@@ -0,0 +1,81 @@
+#
+# Exercise scoutfs recompute-xattr-total.  Uses totl-delta-inject(1) to seed
+# corruption.
+#
+
+t_require_commands setfattr scoutfs sync rm touch totl-delta-inject
+
+# force a log merge then read-xattr-totals filtered to our own keys
+read_totals()
+{
+	t_force_log_merge
+	sync
+	echo 1 > $(t_debugfs_path)/drop_weak_item_cache
+	scoutfs read-xattr-totals -p "$T_M0" | \
+		grep -E '^8888\.' || true
+}
+
+# Print recompute warnings emitted since the last snapshot, with the
+# volatile timestamp/fsid/rid prefix stripped, for golden comparison.
+DMESG_SNAP="$T_TMPDIR/dmesg.recompute.snap"
+dmesg > "$DMESG_SNAP"
+
+recompute_warn()
+{
+	local cur="$T_TMPDIR/dmesg.recompute.cur"
+
+	dmesg > "$cur"
+	diff "$DMESG_SNAP" "$cur" | \
+		sed -n 's/^> \[ *[0-9.]\+\] scoutfs [^ ]\+ warning: \(totl recompute applying delta .*\)$/\1/p'
+	mv "$cur" "$DMESG_SNAP"
+}
+
+echo "== setup three files contributing to totl 8888.0.0"
+touch "$T_D0/f1" "$T_D0/f2" "$T_D0/f3"
+setfattr -n scoutfs.totl.inj.8888.0.0 -v 2  "$T_D0/f1"
+setfattr -n scoutfs.totl.inj.8888.0.0 -v 8  "$T_D0/f2"
+setfattr -n scoutfs.totl.inj.8888.0.0 -v 32 "$T_D0/f3"
+
+echo "== merge baseline into fs_root"
+read_totals
+
+echo "== recompute on a clean baseline is a no-op"
+scoutfs recompute-xattr-total -p "$T_M0" 8888.0.0
+recompute_warn
+read_totals
+
+echo "== inject (+128, +2) corrupts totl 8888.0.0"
+totl-delta-inject "$T_M0" 8888.0.0 128 2
+read_totals
+
+echo "== recompute restores 8888.0.0"
+scoutfs recompute-xattr-total -p "$T_M0" 8888.0.0
+recompute_warn
+read_totals
+
+echo "== inject (-50, +1) corrupts totl 8888.0.0 again"
+totl-delta-inject "$T_M0" 8888.0.0 -50 1
+read_totals
+
+echo "== recompute restores 8888.0.0"
+scoutfs recompute-xattr-total -p "$T_M0" 8888.0.0
+recompute_warn
+read_totals
+
+echo "== recompute on an unused key is a no-op"
+scoutfs recompute-xattr-total -p "$T_M0" 8888.1.1
+recompute_warn
+read_totals
+
+echo "== inject (+7, +1) at unused key 8888.1.1 then recompute clears it"
+totl-delta-inject "$T_M0" 8888.1.1 7 1
+read_totals
+scoutfs recompute-xattr-total -p "$T_M0" 8888.1.1
+recompute_warn
+read_totals
+
+echo "== cleanup"
+rm -f "$T_D0/f1" "$T_D0/f2" "$T_D0/f3"
+read_totals
+
+t_pass