bcachefs: Add a manual trigger for lock wakeups

Spotted a lockup once that appeared to be a lost wakeup. Adding a manual
trigger for lock wakeups will make it easy to tell if that's what it is
next time it occurs.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index d10ac84..96c107e 100644 (file)
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -156,6 +156,7 @@ write_attribute(trigger_gc);
 write_attribute(trigger_discards);
 write_attribute(trigger_invalidates);
 write_attribute(prune_cache);
+write_attribute(btree_wakeup);
 rw_attribute(btree_gc_periodic);
 rw_attribute(gc_gens_pos);
 
@@ -363,6 +364,21 @@ static void bch2_gc_gens_pos_to_text(struct printbuf *out, struct bch_fs *c)
        prt_printf(out, "\n");
 }
 
+static void bch2_btree_wakeup_all(struct bch_fs *c)
+{
+       struct btree_trans *trans;
+
+       mutex_lock(&c->btree_trans_lock);
+       list_for_each_entry(trans, &c->btree_trans_list, list) {
+               struct btree_bkey_cached_common *b = READ_ONCE(trans->locking);
+
+               if (b)
+                       six_lock_wakeup_all(&b->lock);
+
+       }
+       mutex_unlock(&c->btree_trans_lock);
+}
+
 SHOW(bch2_fs)
 {
        struct bch_fs *c = container_of(kobj, struct bch_fs, kobj);
@@ -483,6 +499,9 @@ STORE(bch2_fs)
                c->btree_cache.shrink.scan_objects(&c->btree_cache.shrink, &sc);
        }
 
+       if (attr == &sysfs_btree_wakeup)
+               bch2_btree_wakeup_all(c);
+
        if (attr == &sysfs_trigger_gc) {
                /*
                 * Full gc is currently incompatible with btree key cache:
@@ -614,6 +633,7 @@ struct attribute *bch2_fs_internal_files[] = {
        &sysfs_trigger_discards,
        &sysfs_trigger_invalidates,
        &sysfs_prune_cache,
+       &sysfs_btree_wakeup,
 
        &sysfs_gc_gens_pos,