Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs updates from Al Viro:
 "Assorted cleanups and fixes.

  Probably the most interesting part long-term is ->d_init() - that will
  have a bunch of followups in (at least) ceph and lustre, but we'll
  need to sort the barrier-related rules before it can get used for
  really non-trivial stuff.

  Another fun thing is the merge of ->d_iput() callers (dentry_iput()
  and dentry_unlink_inode()) and a bunch of ->d_compare() ones (all
  except the one in __d_lookup_lru())"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  fs/dcache.c: avoid soft-lockup in dput()
  vfs: new d_init method
  vfs: Update lookup_dcache() comment
  bdev: get rid of ->bd_inodes
  Remove last traces of ->sync_page
  new helper: d_same_name()
  dentry_cmp(): use lockless_dereference() instead of smp_read_barrier_depends()
  vfs: clean up documentation
  vfs: document ->d_real()
  vfs: merge .d_select_inode() into .d_real()
  unify dentry_iput() and dentry_unlink_inode()
  binfmt_misc: ->s_root is not going anywhere
  drop redundant ->owner initializations
  ufs: get rid of redundant checks
  orangefs: constify inode_operations
  missed comment updates from ->direct_IO() prototype change
  file_inode(f)->i_mapping is f->f_mapping
  trim fsnotify hooks a bit
  9p: new helper - v9fs_parent_fid()
  debugfs: ->d_parent is never NULL or negative
  ...

include/linux/dcache.h

@@ -133,14 +133,15 @@ struct dentry_operations {
 	int (*d_compare)(const struct dentry *, const struct dentry *,
 			unsigned int, const char *, const struct qstr *);
 	int (*d_delete)(const struct dentry *);
+	int (*d_init)(struct dentry *);
 	void (*d_release)(struct dentry *);
 	void (*d_prune)(struct dentry *);
 	void (*d_iput)(struct dentry *, struct inode *);
 	char *(*d_dname)(struct dentry *, char *, int);
 	struct vfsmount *(*d_automount)(struct path *);
 	int (*d_manage)(struct dentry *, bool);
-	struct inode *(*d_select_inode)(struct dentry *, unsigned);
-	struct dentry *(*d_real)(struct dentry *, struct inode *);
+	struct dentry *(*d_real)(struct dentry *, const struct inode *,
+				 unsigned int);
 } ____cacheline_aligned;
 
 /*
@@ -206,10 +207,8 @@ struct dentry_operations {
 
 #define DCACHE_MAY_FREE			0x00800000
 #define DCACHE_FALLTHRU			0x01000000 /* Fall through to lower layer */
-#define DCACHE_OP_SELECT_INODE		0x02000000 /* Unioned entry: dcache op selects inode */
-
-#define DCACHE_ENCRYPTED_WITH_KEY	0x04000000 /* dir is encrypted with a valid key */
-#define DCACHE_OP_REAL			0x08000000
+#define DCACHE_ENCRYPTED_WITH_KEY	0x02000000 /* dir is encrypted with a valid key */
+#define DCACHE_OP_REAL			0x04000000
 
 #define DCACHE_PAR_LOOKUP		0x10000000 /* being looked up (with parent locked shared) */
 #define DCACHE_DENTRY_CURSOR		0x20000000
@@ -557,25 +556,27 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
 	return upper;
 }
 
-static inline struct dentry *d_real(struct dentry *dentry)
+/**
+ * d_real - Return the real dentry
+ * @dentry: the dentry to query
+ * @inode: inode to select the dentry from multiple layers (can be NULL)
+ * @flags: open flags to control copy-up behavior
+ *
+ * If dentry is on an union/overlay, then return the underlying, real dentry.
+ * Otherwise return the dentry itself.
+ *
+ * See also: Documentation/filesystems/vfs.txt
+ */
+static inline struct dentry *d_real(struct dentry *dentry,
+				    const struct inode *inode,
+				    unsigned int flags)
 {
 	if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
-		return dentry->d_op->d_real(dentry, NULL);
+		return dentry->d_op->d_real(dentry, inode, flags);
 	else
 		return dentry;
 }
 
-static inline struct inode *vfs_select_inode(struct dentry *dentry,
-					     unsigned open_flags)
-{
-	struct inode *inode = d_inode(dentry);
-
-	if (inode && unlikely(dentry->d_flags & DCACHE_OP_SELECT_INODE))
-		inode = dentry->d_op->d_select_inode(dentry, open_flags);
-
-	return inode;
-}
-
 /**
  * d_real_inode - Return the real inode
  * @dentry: The dentry to query
@@ -585,7 +586,7 @@ static inline struct inode *vfs_select_inode(struct dentry *dentry,
  */
 static inline struct inode *d_real_inode(struct dentry *dentry)
 {
-	return d_backing_inode(d_real(dentry));
+	return d_backing_inode(d_real(dentry, NULL, 0));
 }
 
 

include/linux/fs.h

@@ -457,7 +457,6 @@ struct block_device {
 	struct inode *		bd_inode;	/* will die */
 	struct super_block *	bd_super;
 	struct mutex		bd_mutex;	/* open/close mutex */
-	struct list_head	bd_inodes;
 	void *			bd_claiming;
 	void *			bd_holder;
 	int			bd_holders;
@@ -1271,12 +1270,7 @@ static inline struct inode *file_inode(const struct file *f)
 
 static inline struct dentry *file_dentry(const struct file *file)
 {
-	struct dentry *dentry = file->f_path.dentry;
-
-	if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
-		return dentry->d_op->d_real(dentry, file_inode(file));
-	else
-		return dentry;
+	return d_real(file->f_path.dentry, file_inode(file), 0);
 }
 
 static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)

include/linux/fsnotify.h

@@ -51,18 +51,6 @@ static inline int fsnotify_perm(struct file *file, int mask)
 	return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 }
 
-/*
- * fsnotify_d_move - dentry has been moved
- */
-static inline void fsnotify_d_move(struct dentry *dentry)
-{
-	/*
-	 * On move we need to update dentry->d_flags to indicate if the new parent
-	 * cares about events from this dentry.
-	 */
-	__fsnotify_update_dcache_flags(dentry);
-}
-
 /*
  * fsnotify_link_count - inode's link count changed
  */

include/linux/fsnotify_backend.h

@@ -267,10 +267,8 @@ static inline int fsnotify_inode_watches_children(struct inode *inode)
  * Update the dentry with a flag indicating the interest of its parent to receive
  * filesystem events when those events happens to this dentry->d_inode.
  */
-static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
+static inline void fsnotify_update_flags(struct dentry *dentry)
 {
-	struct dentry *parent;
-
 	assert_spin_locked(&dentry->d_lock);
 
 	/*
@@ -280,21 +278,12 @@ static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
 	 * find our entry, so it will spin until we complete here, and update
 	 * us with the new state.
 	 */
-	parent = dentry->d_parent;
-	if (parent->d_inode && fsnotify_inode_watches_children(parent->d_inode))
+	if (fsnotify_inode_watches_children(dentry->d_parent->d_inode))
 		dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
 	else
 		dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
 }
 
-/*
- * fsnotify_d_instantiate - instantiate a dentry for inode
- */
-static inline void __fsnotify_d_instantiate(struct dentry *dentry)
-{
-	__fsnotify_update_dcache_flags(dentry);
-}
-
 /* called from fsnotify listeners, such as fanotify or dnotify */
 
 /* create a new group */
@@ -386,10 +375,7 @@ static inline void __fsnotify_inode_delete(struct inode *inode)
 static inline void __fsnotify_vfsmount_delete(struct vfsmount *mnt)
 {}
 
-static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
-{}
-
-static inline void __fsnotify_d_instantiate(struct dentry *dentry)
+static inline void fsnotify_update_flags(struct dentry *dentry)
 {}
 
 static inline u32 fsnotify_get_cookie(void)