ext4: add lockdep annotations for i_data_sem

[cascardo/linux.git] / fs / ext4 / ext4.h

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 7e4e3e9..6a857af 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -911,6 +911,29 @@ do {                                                                              \
 
 #include "extents_status.h"
 
+/*
+ * Lock subclasses for i_data_sem in the ext4_inode_info structure.
+ *
+ * These are needed to avoid lockdep false positives when we need to
+ * allocate blocks to the quota inode during ext4_map_blocks(), while
+ * holding i_data_sem for a normal (non-quota) inode.  Since we don't
+ * do quota tracking for the quota inode, this avoids deadlock (as
+ * well as infinite recursion, since it isn't turtles all the way
+ * down...)
+ *
+ *  I_DATA_SEM_NORMAL - Used for most inodes
+ *  I_DATA_SEM_OTHER  - Used by move_inode.c for the second normal inode
+ *                       where the second inode has larger inode number
+ *                       than the first
+ *  I_DATA_SEM_QUOTA  - Used for quota inodes only
+ */
+enum {
+       I_DATA_SEM_NORMAL = 0,
+       I_DATA_SEM_OTHER,
+       I_DATA_SEM_QUOTA,
+};
+
+
 /*
  * fourth extended file system inode data in memory
  */