1 files changed, 41 insertions, 18 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index d8358799c594..df334cbacc6d 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -404,26 +404,11 @@ static inline bool d_mountpoint(const struct dentry *dentry)
 /*
  * Directory cache entry type accessor functions.
  */
-static inline void __d_set_type(struct dentry *dentry, unsigned type)
-{
-        dentry->d_flags = (dentry->d_flags & ~DCACHE_ENTRY_TYPE) | type;
-}
-
-static inline void __d_clear_type(struct dentry *dentry)
-{
-        __d_set_type(dentry, DCACHE_MISS_TYPE);
-}
-
-static inline void d_set_type(struct dentry *dentry, unsigned type)
-{
-        spin_lock(&dentry->d_lock);
-        __d_set_type(dentry, type);
-        spin_unlock(&dentry->d_lock);
-}
-
 static inline unsigned __d_entry_type(const struct dentry *dentry)
 {
-        return dentry->d_flags & DCACHE_ENTRY_TYPE;
+        unsigned type = READ_ONCE(dentry->d_flags);
+        smp_rmb();
+        return type & DCACHE_ENTRY_TYPE;
 }
 
 static inline bool d_is_miss(const struct dentry *dentry)
@@ -482,6 +467,44 @@ static inline bool d_is_positive(const struct dentry *dentry)
         return !d_is_negative(dentry);
 }
 
+/**
+ * d_really_is_negative - Determine if a dentry is really negative (ignoring fallthroughs)
+ * @dentry: The dentry in question
+ *
+ * Returns true if the dentry represents either an absent name or a name that
+ * doesn't map to an inode (ie. ->d_inode is NULL).  The dentry could represent
+ * a true miss, a whiteout that isn't represented by a 0,0 chardev or a
+ * fallthrough marker in an opaque directory.
+ *
+ * Note!  (1) This should be used *only* by a filesystem to examine its own
+ * dentries.  It should not be used to look at some other filesystem's
+ * dentries.  (2) It should also be used in combination with d_inode() to get
+ * the inode.  (3) The dentry may have something attached to ->d_lower and the
+ * type field of the flags may be set to something other than miss or whiteout.
+ */
+static inline bool d_really_is_negative(const struct dentry *dentry)
+{
+        return dentry->d_inode == NULL;
+}
+
+/**
+ * d_really_is_positive - Determine if a dentry is really positive (ignoring fallthroughs)
+ * @dentry: The dentry in question
+ *
+ * Returns true if the dentry represents a name that maps to an inode
+ * (ie. ->d_inode is not NULL).  The dentry might still represent a whiteout if
+ * that is represented on medium as a 0,0 chardev.
+ *
+ * Note!  (1) This should be used *only* by a filesystem to examine its own
+ * dentries.  It should not be used to look at some other filesystem's
+ * dentries.  (2) It should also be used in combination with d_inode() to get
+ * the inode.
+ */
+static inline bool d_really_is_positive(const struct dentry *dentry)
+{
+        return dentry->d_inode != NULL;
+}
+
 extern void d_set_fallthru(struct dentry *dentry);
 
 static inline bool d_is_fallthru(const struct dentry *dentry)