Merge pull request #87 from versity/zab/lock_invalidation_recovery

Zab/lock invalidation recovery

kmod/src/lock.c

@@ -289,6 +289,7 @@ static struct scoutfs_lock *lock_alloc(struct super_block *sb,
 	lock->sb = sb;
 	init_waitqueue_head(&lock->waitq);
 	lock->mode = SCOUTFS_LOCK_NULL;
+	lock->invalidating_mode = SCOUTFS_LOCK_NULL;
 
 	atomic64_set(&lock->forest_bloom_nr, 0);
 
@@ -666,7 +667,9 @@ struct inv_req {
  *
  * Before we start invalidating the lock we set the lock to the new
  * mode, preventing further incompatible users of the old mode from
- * using the lock while we're invalidating.
+ * using the lock while we're invalidating.  We record the previously
+ * granted mode so that we can send lock recover responses with the old
+ * granted mode during invalidation.
  */
 static void lock_invalidate_worker(struct work_struct *work)
 {
@@ -691,7 +694,8 @@ static void lock_invalidate_worker(struct work_struct *work)
 		if (!lock_counts_match(nl->new_mode, lock->users))
 			continue;
 
-		/* set the new mode, no incompatible users during inval */
+		/* set the new mode, no incompatible users during inval, recov needs old */
+		lock->invalidating_mode = lock->mode;
 		lock->mode = nl->new_mode;
 
 		/* move everyone that's ready to our private list */
@@ -734,6 +738,8 @@ static void lock_invalidate_worker(struct work_struct *work)
 		list_del(&ireq->head);
 		kfree(ireq);
 
+		lock->invalidating_mode = SCOUTFS_LOCK_NULL;
+
 		if (list_empty(&lock->inv_list)) {
 			/* finish if another request didn't arrive */
 			list_del_init(&lock->inv_head);
@@ -824,6 +830,7 @@ int scoutfs_lock_recover_request(struct super_block *sb, u64 net_id,
 {
 	DECLARE_LOCK_INFO(sb, linfo);
 	struct scoutfs_net_lock_recover *nlr;
+	enum scoutfs_lock_mode mode;
 	struct scoutfs_lock *lock;
 	struct scoutfs_lock *next;
 	struct rb_node *node;
@@ -844,10 +851,15 @@ int scoutfs_lock_recover_request(struct super_block *sb, u64 net_id,
 
 	for (i = 0; lock && i < SCOUTFS_NET_LOCK_MAX_RECOVER_NR; i++) {
 
+		if (lock->invalidating_mode != SCOUTFS_LOCK_NULL)
+			mode = lock->invalidating_mode;
+		else
+			mode = lock->mode;
+
 		nlr->locks[i].key = lock->start;
 		nlr->locks[i].write_seq = cpu_to_le64(lock->write_seq);
-		nlr->locks[i].old_mode = lock->mode;
-		nlr->locks[i].new_mode = lock->mode;
+		nlr->locks[i].old_mode = mode;
+		nlr->locks[i].new_mode = mode;
 
 		node = rb_next(&lock->node);
 		if (node)

kmod/src/lock.h

@@ -39,6 +39,7 @@ struct scoutfs_lock {
 	struct list_head cov_list;
 
 	enum scoutfs_lock_mode mode;
+	enum scoutfs_lock_mode invalidating_mode;
 	unsigned int waiters[SCOUTFS_LOCK_NR_MODES];
 	unsigned int users[SCOUTFS_LOCK_NR_MODES];
 

tests/golden/lock-recover-invalidate

@@ -0,0 +1,3 @@
+== starting background invalidating read/write load
+== 60s of lock recovery during invalidating load
+== stopping background load

tests/sequence

@@ -17,6 +17,7 @@ lock-refleak.sh
 lock-shrink-consistency.sh
 lock-pr-cw-conflict.sh
 lock-revoke-getcwd.sh
+lock-recover-invalidate.sh
 export-lookup-evict-race.sh
 createmany-parallel.sh
 createmany-large-names.sh

tests/tests/lock-recover-invalidate.sh

@@ -0,0 +1,43 @@
+#
+# trigger server failover and lock recovery during heavy invalidating
+# load on multiple mounts
+#
+
+majority_nr=$(t_majority_count)
+quorum_nr=$T_QUORUM
+
+test "$quorum_nr" == "$majority_nr" && \
+        t_skip "need remaining majority when leader unmounted"
+
+test "$T_NR_MOUNTS" -lt "$((quorum_nr + 2))" && \
+        t_skip "need at least 2 non-quorum load mounts"
+
+echo "== starting background invalidating read/write load"
+touch "$T_D0/file"
+load_pids=""
+for i in $(t_fs_nrs); do
+	if [ "$i" -ge "$quorum_nr" ]; then
+		eval path="\$T_D${i}/file"
+
+		(while true; do touch $path > /dev/null 2>&1; done) &
+		load_pids="$load_pids $!"
+		(while true; do stat $path > /dev/null 2>&1; done) &
+		load_pids="$load_pids $!"
+	fi
+done
+
+# had it reproduce in ~40s on wimpy debug kernel guests
+LENGTH=60
+echo "== ${LENGTH}s of lock recovery during invalidating load"
+END=$((SECONDS + LENGTH))
+while [ "$SECONDS" -lt "$END" ]; do
+        sv=$(t_server_nr)
+        t_umount $sv
+        t_mount $sv
+	# new server had to process greeting for mount to finish
+done
+
+echo "== stopping background load"
+kill $load_pids
+
+t_pass