Commit fd7732e033e3 ("fs/locks: create a tree of dependent requests.")
has put blocked locks into a tree.

So, with a for loop, we can't check all locks information.

To solve this problem, we should traverse the tree by non-recursion DFS.

Signed-off-by: Luo Longjun <luolong...@huawei.com>
---
 fs/locks.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 67 insertions(+), 8 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 99ca97e81b7a..fdf240626777 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2827,8 +2827,14 @@ struct locks_iterator {
        loff_t  li_pos;
 };
 
+struct locks_traverse_list {
+       struct list_head head;
+       struct file_lock *lock;
+       int level;
+};
+
 static void lock_get_status(struct seq_file *f, struct file_lock *fl,
-                           loff_t id, char *pfx)
+                           loff_t id, char *pfx, int repeat)
 {
        struct inode *inode = NULL;
        unsigned int fl_pid;
@@ -2844,7 +2850,11 @@ static void lock_get_status(struct seq_file *f, struct 
file_lock *fl,
        if (fl->fl_file != NULL)
                inode = locks_inode(fl->fl_file);
 
-       seq_printf(f, "%lld:%s ", id, pfx);
+       seq_printf(f, "%lld: ", id);
+
+       if (repeat)
+               seq_printf(f, "%*s", repeat - 1 + strlen(pfx), pfx);
+
        if (IS_POSIX(fl)) {
                if (fl->fl_flags & FL_ACCESS)
                        seq_puts(f, "ACCESS");
@@ -2912,17 +2922,66 @@ static int locks_show(struct seq_file *f, void *v)
        struct file_lock *fl, *bfl;
        struct pid_namespace *proc_pidns = 
proc_pid_ns(file_inode(f->file)->i_sb);
 
+       struct list_head root;
+       struct list_head *tail = &root;
+       struct list_head *pos, *tmp;
+       struct locks_traverse_list *node, *node_child;
+
+       int ret = 0;
+
        fl = hlist_entry(v, struct file_lock, fl_link);
 
        if (locks_translate_pid(fl, proc_pidns) == 0)
-               return 0;
+               return ret;
+
+       INIT_LIST_HEAD(&root);
 
-       lock_get_status(f, fl, iter->li_pos, "");
+       node = kmalloc(sizeof(struct locks_traverse_list), GFP_KERNEL);
+       if (!node) {
+               ret = -ENOMEM;
+               goto out;
+       }
 
-       list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member)
-               lock_get_status(f, bfl, iter->li_pos, " ->");
+       node->level = 0;
+       node->lock = fl;
+       list_add(&node->head, tail);
+       tail = &node->head;
 
-       return 0;
+       while (tail != &root) {
+               node = list_entry(tail, struct locks_traverse_list, head);
+               if (!node->level)
+                       lock_get_status(f, node->lock, iter->li_pos, "", 
node->level);
+               else
+                       lock_get_status(f, node->lock, iter->li_pos, "-> ", 
node->level);
+
+               tmp = tail->prev;
+               list_del(tail);
+               tail = tmp;
+
+               list_for_each_entry_reverse(bfl, 
&node->lock->fl_blocked_requests,
+                                               fl_blocked_member) {
+                       node_child = kmalloc(sizeof(struct 
locks_traverse_list), GFP_KERNEL);
+                       if (!node_child) {
+                               ret = -ENOMEM;
+                               goto out;
+                       }
+
+                       node_child->level = node->level + 1;
+                       node_child->lock = bfl;
+                       list_add(&node_child->head, tail);
+                       tail = &node_child->head;
+               }
+               kfree(node);
+       }
+
+out:
+       list_for_each_safe(pos, tmp, &root) {
+               node = list_entry(pos, struct locks_traverse_list, head);
+               list_del(pos);
+               if (!node)
+                       kfree(node);
+       }
+       return ret;
 }
 
 static void __show_fd_locks(struct seq_file *f,
@@ -2941,7 +3000,7 @@ static void __show_fd_locks(struct seq_file *f,
 
                (*id)++;
                seq_puts(f, "lock:\t");
-               lock_get_status(f, fl, *id, "");
+               lock_get_status(f, fl, *id, "", 0);
        }
 }
 
-- 
2.17.1

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