[RFC][PATCH] fanotify: allow setting FAN_CREATE in mount mark mask

@@ -3288,7 +3288,7 @@ static const char *open_last_lookups(struct nameidata *nd,
 		inode_lock_shared(dir->d_inode);
 	dentry = lookup_open(nd, file, op, got_write);
 	if (!IS_ERR(dentry) && (file->f_mode & FMODE_CREATED))
-		fsnotify_create(dir->d_inode, dentry);
+		fsnotify_path_create(&nd->path, dentry);
 	if (open_flag & O_CREAT)
 		inode_unlock(dir->d_inode);
 	else

@@ -3560,6 +3560,20 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
 	return file;
 }
 
+static void d_set_path_create(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	dentry->d_flags |= DCACHE_PATH_CREATE;
+	spin_unlock(&dentry->d_lock);
+}
+
+static void d_clear_path_create(struct dentry *dentry)
+{
+	spin_lock(&dentry->d_lock);
+	dentry->d_flags &= ~DCACHE_PATH_CREATE;
+	spin_unlock(&dentry->d_lock);
+}
+
 static struct dentry *filename_create(int dfd, struct filename *name,
 				struct path *path, unsigned int lookup_flags)
 {

@@ -3617,6 +3631,8 @@ static struct dentry *filename_create(int dfd, struct filename *name,
 		goto fail;
 	}
 	putname(name);
+	/* Start "path create" context that ends in done_path_create() */
+	d_set_path_create(dentry);
 	return dentry;
 fail:
 	dput(dentry);

@@ -3641,6 +3657,9 @@ EXPORT_SYMBOL(kern_path_create);
 
 void done_path_create(struct path *path, struct dentry *dentry)
 {
+	if (d_inode(dentry))
+		fsnotify_path_create(path, dentry);
+	d_clear_path_create(dentry);
 	dput(dentry);
 	inode_unlock(path->dentry->d_inode);
 	mnt_drop_write(path->mnt);

@@ -213,7 +213,7 @@ struct dentry_operations {
 #define DCACHE_SYMLINK_TYPE		0x00600000 /* Symlink (or fallthru to such) */
 
 #define DCACHE_MAY_FREE			0x00800000
-/* Was #define DCACHE_FALLTHRU			0x01000000 */
+#define DCACHE_PATH_CREATE		0x01000000 /* "path_create" context */
 #define DCACHE_NOKEY_NAME		0x02000000 /* Encrypted name encoded without key */
 #define DCACHE_OP_REAL			0x04000000
 

@@ -65,10 +65,10 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
 
 /*
  * Events that can be reported with data type FSNOTIFY_EVENT_PATH.
- * Note that FAN_MODIFY can also be reported with data type
+ * Note that FAN_MODIFY and FAN_CREATE can also be reported with data type
  * FSNOTIFY_EVENT_INODE.
  */
-#define FANOTIFY_PATH_EVENTS	(FAN_ACCESS | FAN_MODIFY | \
+#define FANOTIFY_PATH_EVENTS	(FAN_ACCESS | FAN_MODIFY | FAN_CREATE | \
 				 FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
 
 /*

@@ -78,8 +78,8 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
 #define FANOTIFY_DIRENT_EVENTS	(FAN_MOVE | FAN_CREATE | FAN_DELETE)
 
 /* Events that can only be reported with data type FSNOTIFY_EVENT_INODE */
-#define FANOTIFY_INODE_EVENTS	(FANOTIFY_DIRENT_EVENTS | \
-				 FAN_ATTRIB | FAN_MOVE_SELF | FAN_DELETE_SELF)
+#define FANOTIFY_INODE_EVENTS	(FAN_MOVE | FAN_DELETE | FAN_ATTRIB | \
+				 FAN_MOVE_SELF | FAN_DELETE_SELF)
 
 /* Events that user can request to be notified on */
 #define FANOTIFY_EVENTS		(FANOTIFY_PATH_EVENTS | \

@@ -179,6 +179,30 @@ static inline void fsnotify_inoderemove(struct inode *inode)
 	__fsnotify_inode_delete(inode);
 }
 
+/*
+ * fsnotify_path_create - an inode was linked to namespace
+ *
+ * This higher level hook is called in addition to fsnotify_create(),
+ * fsnotify_mkdir() and fsnotify_link() vfs hooks when the mount context is
+ * available, so that FS_CREATE event can be added to a mount mark mask.
+ *
+ * In that case the, DCACHE_PATH_CREATE flag is set to suppress the FS_CREATE
+ * event in the lower level vfs hooks.
+ */
+static inline void fsnotify_path_create(struct path *path,
+					struct dentry *child)
+{
+	struct inode *dir = path->dentry->d_inode;
+	__u32 mask = FS_CREATE;
+
+	WARN_ON_ONCE(!inode_is_locked(dir));
+
+	if (S_ISDIR(d_inode(child)->i_mode))
+		mask |= FS_ISDIR;
+
+	fsnotify(mask, path, FSNOTIFY_EVENT_PATH, dir, &child->d_name, NULL, 0);
+}
+
 /*
  * fsnotify_create - 'name' was linked in
  */

@@ -186,6 +210,10 @@ static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
 {
 	audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 
+	/* fsnotify_path_create() will be called */
+	if (dentry->d_flags & DCACHE_PATH_CREATE)
+		return;
+
 	fsnotify_dirent(inode, dentry, FS_CREATE);
 }
 

@@ -200,6 +228,10 @@ static inline void fsnotify_link(struct inode *dir, struct inode *inode,
 	fsnotify_link_count(inode);
 	audit_inode_child(dir, new_dentry, AUDIT_TYPE_CHILD_CREATE);
 
+	/* fsnotify_path_create() will be called */
+	if (new_dentry->d_flags & DCACHE_PATH_CREATE)
+		return;
+
 	fsnotify_name(dir, FS_CREATE, inode, &new_dentry->d_name, 0);
 }
 

@@ -223,6 +255,10 @@ static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
 {
 	audit_inode_child(inode, dentry, AUDIT_TYPE_CHILD_CREATE);
 
+	/* fsnotify_path_create() will be called */
+	if (dentry->d_flags & DCACHE_PATH_CREATE)
+		return;
+
 	fsnotify_dirent(inode, dentry, FS_CREATE | FS_ISDIR);
 }