[patch 37/61] lock validator: special locking: dcache

[Ingo Molnar]

From: Ingo Molnar <mingo@xxxxxxx>

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

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
---
 fs/dcache.c            |    6 +++---
 include/linux/dcache.h |   12 ++++++++++++
 2 files changed, 15 insertions(+), 3 deletions(-)

Index: linux/fs/dcache.c
===================================================================
--- linux.orig/fs/dcache.c
+++ linux/fs/dcache.c
@@ -1380,10 +1380,10 @@ void d_move(struct dentry * dentry, stru
 	 */
 	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 */
@@ -1420,7 +1420,7 @@ already_unhashed:
 	}
 
 	list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
-	spin_unlock(&target->d_lock);
+	spin_unlock_non_nested(&target->d_lock);
 	fsnotify_d_move(dentry);
 	spin_unlock(&dentry->d_lock);
 	write_sequnlock(&rename_lock);
Index: linux/include/linux/dcache.h
===================================================================
--- linux.orig/include/linux/dcache.h
+++ linux/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 types:
+ *
+ * 0: normal
+ * 1: nested
+ */
+enum dentry_d_lock_type
+{
+	DENTRY_D_LOCK_NORMAL,
+	DENTRY_D_LOCK_NESTED
+};
+
 struct dentry_operations {
 	int (*d_revalidate)(struct dentry *, struct nameidata *);
 	int (*d_hash) (struct dentry *, struct qstr *);
-
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