1 files changed, 96 insertions, 7 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 92c08cf7670e..d8358799c594 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -215,13 +215,16 @@ struct dentry_operations {
 #define DCACHE_LRU_LIST                 0x00080000
 
 #define DCACHE_ENTRY_TYPE               0x00700000
-#define DCACHE_MISS_TYPE                0x00000000 /* Negative dentry */
-#define DCACHE_DIRECTORY_TYPE           0x00100000 /* Normal directory */
-#define DCACHE_AUTODIR_TYPE             0x00200000 /* Lookupless directory (presumed automount) */
-#define DCACHE_SYMLINK_TYPE             0x00300000 /* Symlink */
-#define DCACHE_FILE_TYPE                0x00400000 /* Other file type */
+#define DCACHE_MISS_TYPE                0x00000000 /* Negative dentry (maybe fallthru to nowhere) */
+#define DCACHE_WHITEOUT_TYPE            0x00100000 /* Whiteout dentry (stop pathwalk) */
+#define DCACHE_DIRECTORY_TYPE           0x00200000 /* Normal directory */
+#define DCACHE_AUTODIR_TYPE             0x00300000 /* Lookupless directory (presumed automount) */
+#define DCACHE_REGULAR_TYPE             0x00400000 /* Regular file type (or fallthru to such) */
+#define DCACHE_SPECIAL_TYPE             0x00500000 /* Other file type (or fallthru to such) */
+#define DCACHE_SYMLINK_TYPE             0x00600000 /* Symlink (or fallthru to such) */
 
 #define DCACHE_MAY_FREE                 0x00800000
+#define DCACHE_FALLTHRU                 0x01000000 /* Fall through to lower layer */
 
 extern seqlock_t rename_lock;
 
@@ -423,6 +426,16 @@ static inline unsigned __d_entry_type(const struct dentry *dentry)
         return dentry->d_flags & DCACHE_ENTRY_TYPE;
 }
 
+static inline bool d_is_miss(const struct dentry *dentry)
+{
+        return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
+}
+
+static inline bool d_is_whiteout(const struct dentry *dentry)
+{
+        return __d_entry_type(dentry) == DCACHE_WHITEOUT_TYPE;
+}
+
 static inline bool d_can_lookup(const struct dentry *dentry)
 {
         return __d_entry_type(dentry) == DCACHE_DIRECTORY_TYPE;
@@ -443,14 +456,25 @@ static inline bool d_is_symlink(const struct dentry *dentry)
         return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
 }
 
+static inline bool d_is_reg(const struct dentry *dentry)
+{
+        return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
+}
+
+static inline bool d_is_special(const struct dentry *dentry)
+{
+        return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
+}
+
 static inline bool d_is_file(const struct dentry *dentry)
 {
-        return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
+        return d_is_reg(dentry) || d_is_special(dentry);
 }
 
 static inline bool d_is_negative(const struct dentry *dentry)
 {
-        return __d_entry_type(dentry) == DCACHE_MISS_TYPE;
+        // TODO: check d_is_whiteout(dentry) also.
+        return d_is_miss(dentry);
 }
 
 static inline bool d_is_positive(const struct dentry *dentry)
@@ -458,10 +482,75 @@ static inline bool d_is_positive(const struct dentry *dentry)
         return !d_is_negative(dentry);
 }
 
+extern void d_set_fallthru(struct dentry *dentry);
+
+static inline bool d_is_fallthru(const struct dentry *dentry)
+{
+        return dentry->d_flags & DCACHE_FALLTHRU;
+}
+
+
 extern int sysctl_vfs_cache_pressure;
 
 static inline unsigned long vfs_pressure_ratio(unsigned long val)
 {
         return mult_frac(val, sysctl_vfs_cache_pressure, 100);
 }
+
+/**
+ * d_inode - Get the actual inode of this dentry
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode(const struct dentry *dentry)
+{
+        return dentry->d_inode;
+}
+
+/**
+ * d_inode_rcu - Get the actual inode of this dentry with ACCESS_ONCE()
+ * @dentry: The dentry to query
+ *
+ * This is the helper normal filesystems should use to get at their own inodes
+ * in their own dentries and ignore the layering superimposed upon them.
+ */
+static inline struct inode *d_inode_rcu(const struct dentry *dentry)
+{
+        return ACCESS_ONCE(dentry->d_inode);
+}
+
+/**
+ * d_backing_inode - Get upper or lower inode we should be using
+ * @upper: The upper layer
+ *
+ * This is the helper that should be used to get at the inode that will be used
+ * if this dentry were to be opened as a file.  The inode may be on the upper
+ * dentry or it may be on a lower dentry pinned by the upper.
+ *
+ * Normal filesystems should not use this to access their own inodes.
+ */
+static inline struct inode *d_backing_inode(const struct dentry *upper)
+{
+        struct inode *inode = upper->d_inode;
+
+        return inode;
+}
+
+/**
+ * d_backing_dentry - Get upper or lower dentry we should be using
+ * @upper: The upper layer
+ *
+ * This is the helper that should be used to get the dentry of the inode that
+ * will be used if this dentry were opened as a file.  It may be the upper
+ * dentry or it may be a lower dentry pinned by the upper.
+ *
+ * Normal filesystems should not use this to access their own dentries.
+ */
+static inline struct dentry *d_backing_dentry(struct dentry *upper)
+{
+        return upper;
+}
+
 #endif  /* __LINUX_DCACHE_H */