Revert "fsnotify: store struct file not struct path"

This reverts commit 3bcf3860a4ff9bbc522820b4b765e65e4deceb3e (and the
accompanying commit c1e5c954020e "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).

The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.

Fix up various conflicts due to later fsnotify work.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 4d2a82c..3970392 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -84,7 +84,7 @@
 }
 
 /* Notify this dentry's parent about a child's events. */
-void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
+void __fsnotify_parent(struct path *path, struct dentry *dentry, __u32 mask)
 {
 	struct dentry *parent;
 	struct inode *p_inode;
@@ -92,7 +92,7 @@
 	bool should_update_children = false;
 
 	if (!dentry)
-		dentry = file->f_path.dentry;
+		dentry = path->dentry;
 
 	if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
 		return;
@@ -124,8 +124,8 @@
 		 * specifies these are events which came from a child. */
 		mask |= FS_EVENT_ON_CHILD;
 
-		if (file)
-			fsnotify(p_inode, mask, file, FSNOTIFY_EVENT_FILE,
+		if (path)
+			fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH,
 				 dentry->d_name.name, 0);
 		else
 			fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
@@ -217,8 +217,8 @@
 	/* global tests shouldn't care about events on child only the specific event */
 	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
 
-	if (data_is == FSNOTIFY_EVENT_FILE)
-		mnt = ((struct file *)data)->f_path.mnt;
+	if (data_is == FSNOTIFY_EVENT_PATH)
+		mnt = ((struct path *)data)->mnt;
 	else
 		mnt = NULL;