bcachefs: Fix 'hung task' messages in btree node scan

btree node scan has to wait on kthread workers that scan each device,
potentially for awhile.

We would like this to be interruptible, but we may need a different
mechanism than signals for that - we've had bugs in the past where
mounts were failing due to checking for signals, and no explanation on
where they came from.

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

diff --git a/fs/bcachefs/btree_node_scan.c b/fs/bcachefs/btree_node_scan.c
index 678161321e426479334512adbfb10d96f2f64658..de02c0e378c9c6bdfc7ec10a1c8b0db71fc08c28 100644 (file)
--- a/fs/bcachefs/btree_node_scan.c
+++ b/fs/bcachefs/btree_node_scan.c
@@ -13,6 +13,7 @@
 
 #include <linux/kthread.h>
 #include <linux/min_heap.h>
+#include <linux/sched/sysctl.h>
 #include <linux/sort.h>
 
 struct find_btree_nodes_worker {
@@ -313,7 +314,8 @@ static int read_btree_nodes(struct find_btree_nodes *f)
                wake_up_process(t);
        }
 err:
-       closure_sync(&cl);
+       while (closure_sync_timeout(&cl, sysctl_hung_task_timeout_secs * HZ / 2))
+               ;
        return f->ret ?: ret;
 }