[PATCH] new helper - inotify_clone_watch()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/inotify.c b/fs/inotify.c
index 7457501..4b2469b 100644
--- a/fs/inotify.c
+++ b/fs/inotify.c
@@ -667,6 +667,41 @@
EXPORT_SYMBOL_GPL(inotify_add_watch);
/**
+ * inotify_clone_watch - put the watch next to existing one
+ * @old: already installed watch
+ * @new: new watch
+ *
+ * Caller must hold the inotify_mutex of inode we are dealing with;
+ * it is expected to remove the old watch before unlocking the inode.
+ */
+s32 inotify_clone_watch(struct inotify_watch *old, struct inotify_watch *new)
+{
+ struct inotify_handle *ih = old->ih;
+ int ret = 0;
+
+ new->mask = old->mask;
+ new->ih = ih;
+
+ mutex_lock(&ih->mutex);
+
+ /* Initialize a new watch */
+ ret = inotify_handle_get_wd(ih, new);
+ if (unlikely(ret))
+ goto out;
+ ret = new->wd;
+
+ get_inotify_handle(ih);
+
+ new->inode = igrab(old->inode);
+
+ list_add(&new->h_list, &ih->watches);
+ list_add(&new->i_list, &old->inode->inotify_watches);
+out:
+ mutex_unlock(&ih->mutex);
+ return ret;
+}
+
+/**
* inotify_rm_wd - remove a watch from an inotify instance
* @ih: inotify handle
* @wd: watch descriptor to remove