3 files changed, 35 insertions, 8 deletions

diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index b2a2a08523bf..1c2f1b84468b 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -124,15 +124,15 @@ struct dentry {
         void *d_fsdata;                 /* fs-specific data */
 
         struct list_head d_lru;         /* LRU list */
+        struct list_head d_child;       /* child of parent list */
+        struct list_head d_subdirs;     /* our children */
         /*
-         * d_child and d_rcu can share memory
+         * d_alias and d_rcu can share memory
          */
         union {
-                struct list_head d_child;       /* child of parent list */
+                struct hlist_node d_alias;      /* inode alias list */
                 struct rcu_head d_rcu;
         } d_u;
-        struct list_head d_subdirs;     /* our children */
-        struct hlist_node d_alias;      /* inode alias list */
 };
 
 /*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4e41a4a331bb..1c12c681803f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -639,11 +639,13 @@ static inline int inode_unhashed(struct inode *inode)
  * 2: child/target
  * 3: xattr
  * 4: second non-directory
- * The last is for certain operations (such as rename) which lock two
+ * 5: second parent (when locking independent directories in rename)
+ *
+ * I_MUTEX_NONDIR2 is for certain operations (such as rename) which lock two
  * non-directories at once.
  *
  * The locking order between these classes is
- * parent -> child -> normal -> xattr -> second non-directory
+ * parent[2] -> child -> grandchild -> normal -> xattr -> second non-directory
  */
 enum inode_i_mutex_lock_class
 {
@@ -651,7 +653,8 @@ enum inode_i_mutex_lock_class
         I_MUTEX_PARENT,
         I_MUTEX_CHILD,
         I_MUTEX_XATTR,
-        I_MUTEX_NONDIR2
+        I_MUTEX_NONDIR2,
+        I_MUTEX_PARENT2,
 };
 
 void lock_two_nondirectories(struct inode *, struct inode*);
@@ -1464,7 +1467,10 @@ int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
  * This allows the kernel to read directories into kernel space or
  * to have different dirent layouts depending on the binary type.
  */
-typedef int (*filldir_t)(void *, const char *, int, loff_t, u64, unsigned);
+struct dir_context;
+typedef int (*filldir_t)(struct dir_context *, const char *, int, loff_t, u64,
+                         unsigned);
+
 struct dir_context {
         const filldir_t actor;
         loff_t pos;
@@ -2466,6 +2472,7 @@ extern ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, lo
 extern ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
 
 /* fs/block_dev.c */
+extern ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to);
 extern ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from);
 extern int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
                         int datasync);
@@ -2782,6 +2789,11 @@ static inline void inode_has_no_xattr(struct inode *inode)
                 inode->i_flags |= S_NOSEC;
 }
 
+static inline bool is_root_inode(struct inode *inode)
+{
+        return inode == inode->i_sb->s_root->d_inode;
+}
+
 static inline bool dir_emit(struct dir_context *ctx,
                             const char *name, int namelen,
                             u64 ino, unsigned type)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a4a819ffb2d1..53ff1a752d7e 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -617,6 +617,21 @@ static inline void rcu_preempt_sleep_check(void)
 #define RCU_INITIALIZER(v) (typeof(*(v)) __force __rcu *)(v)
 
 /**
+ * lockless_dereference() - safely load a pointer for later dereference
+ * @p: The pointer to load
+ *
+ * Similar to rcu_dereference(), but for situations where the pointed-to
+ * object's lifetime is managed by something other than RCU.  That
+ * "something other" might be reference counting or simple immortality.
+ */
+#define lockless_dereference(p) \
+({ \
+        typeof(p) _________p1 = ACCESS_ONCE(p); \
+        smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
+        (_________p1); \
+})
+
+/**
  * rcu_assign_pointer() - assign to RCU-protected pointer
  * @p: pointer to assign to
  * @v: value to assign (publish)