Merge tag 'locks-v4.9-1' of git://git.samba.org/jlayton/linux

Pull file locking updates from Jeff Layton:
 "Only a single patch from Nikolay this cycle, with a small change to
  better handle /proc/locks in a containerized host"

* tag 'locks-v4.9-1' of git://git.samba.org/jlayton/linux:
  locks: Filter /proc/locks output on proc pid ns

1 files changed, 18 insertions, 3 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 133fb2543d21..90ec67108b22 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2603,9 +2603,20 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
         struct inode *inode = NULL;
         unsigned int fl_pid;
 
-        if (fl->fl_nspid)
-                fl_pid = pid_vnr(fl->fl_nspid);
-        else
+        if (fl->fl_nspid) {
+                struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
+
+                /* Don't let fl_pid change based on who is reading the file */
+                fl_pid = pid_nr_ns(fl->fl_nspid, proc_pidns);
+
+                /*
+                 * If there isn't a fl_pid don't display who is waiting on
+                 * the lock if we are called from locks_show, or if we are
+                 * called from __show_fd_info - skip lock entirely
+                 */
+                if (fl_pid == 0)
+                        return;
+        } else
                 fl_pid = fl->fl_pid;
 
         if (fl->fl_file != NULL)
@@ -2677,9 +2688,13 @@ static int locks_show(struct seq_file *f, void *v)
 {
         struct locks_iterator *iter = f->private;
         struct file_lock *fl, *bfl;
+        struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
 
         fl = hlist_entry(v, struct file_lock, fl_link);
 
+        if (fl->fl_nspid && !pid_nr_ns(fl->fl_nspid, proc_pidns))
+                return 0;
+
         lock_get_status(f, fl, iter->li_pos, "");
 
         list_for_each_entry(bfl, &fl->fl_block, fl_block)