configfs: mutex_lock_nested() fix

configfs_unregister_subsystem() nests a pair of inode i_mutex acquisitions,
and thus needs annotation via mutex_lock_nested().

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index 8a3b6a1a6ad1..452cfd1e785f 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -1176,8 +1176,9 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys)
                 return;
         }
 
-        mutex_lock(&configfs_sb->s_root->d_inode->i_mutex);
-        mutex_lock(&dentry->d_inode->i_mutex);
+        mutex_lock_nested(&configfs_sb->s_root->d_inode->i_mutex,
+                          I_MUTEX_PARENT);
+        mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD);
         if (configfs_detach_prep(dentry)) {
                 printk(KERN_ERR "configfs: Tried to unregister non-empty subsystem!\n");
         }