vfs: add missing unlock in sget()

In sget(), destroy_super(s) is called with s->s_umount held, which makes
lockdep unhappy.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/super.c b/fs/super.c
index 8349ed6..6ce5014 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -371,8 +371,10 @@ retry:
                                continue;
                        if (!grab_super(old))
                                goto retry;
-                       if (s)
+                       if (s) {
+                               up_write(&s->s_umount);
                                destroy_super(s);
+                       }
                        return old;
                }
        }
@@ -387,6 +389,7 @@ retry:
        err = set(s, data);
        if (err) {
                spin_unlock(&sb_lock);
+               up_write(&s->s_umount);
                destroy_super(s);
                return ERR_PTR(err);
        }