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>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/super.c b/fs/super.c
index 8349ed6b141..6ce501447ad 100644
--- 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);
         }