fs: limit filesystem stacking depth

[pandora-kernel.git] / include / linux / fs.h

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 44e856b..a509bee 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -486,6 +486,12 @@ struct iattr {
  */
 #include <linux/quota.h>
 
+/*
+ * Maximum number of layers of fs stack.  Needs to be limited to
+ * prevent kernel stack overflow
+ */
+#define FILESYSTEM_MAX_STACK_DEPTH 2
+
 /** 
  * enum positive_aop_returns - aop return codes with specific semantics
  *
@@ -1497,6 +1503,11 @@ struct super_block {
        int cleancache_poolid;
 
        struct shrinker s_shrink;       /* per-sb shrinker handle */
+
+       /*
+        * Indicates how deep in a filesystem stack this SB is
+        */
+       int s_stack_depth;
 };
 
 /* superblock cache pruning functions */