[PATCH] lockdep: annotate dcache

Teach special (recursive) locking code to the lock validator.  Has no effect
on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 14 insertions, 2 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index bec4de176c81..1b4a3a34ec57 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1339,10 +1339,10 @@ void d_move(struct dentry * dentry, struct dentry * target)
          */
         if (target < dentry) {
                 spin_lock(&target->d_lock);
-                spin_lock(&dentry->d_lock);
+                spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
         } else {
                 spin_lock(&dentry->d_lock);
-                spin_lock(&target->d_lock);
+                spin_lock_nested(&target->d_lock, DENTRY_D_LOCK_NESTED);
         }
 
         /* Move the dentry to the target hash queue, if on different bucket */
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 0dd1610a94a9..471781ffeab1 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -114,6 +114,18 @@ struct dentry {
         unsigned char d_iname[DNAME_INLINE_LEN_MIN];    /* small names */
 };
 
+/*
+ * dentry->d_lock spinlock nesting subclasses:
+ *
+ * 0: normal
+ * 1: nested
+ */
+enum dentry_d_lock_class
+{
+        DENTRY_D_LOCK_NORMAL, /* implicitly used by plain spin_lock() APIs. */
+        DENTRY_D_LOCK_NESTED
+};
+
 struct dentry_operations {
         int (*d_revalidate)(struct dentry *, struct nameidata *);
         int (*d_hash) (struct dentry *, struct qstr *);