4 files changed, 102 insertions, 0 deletions
diff --git a/fs/notify/fanotify/Kconfig b/fs/notify/fanotify/Kconfig
new file mode 100644
index 000000000000..f9d7ae081f85
--- /dev/null
+++ b/fs/notify/fanotify/Kconfig
@@ -0,0 +1,11 @@
+config FANOTIFY
+	bool "Filesystem wide access notification"
+	select FSNOTIFY
+	default y
+	---help---
+	   Say Y here to enable fanotify suport.  fanotify is a file access
+	   notification system which differs from inotify in that it sends
+	   and open file descriptor to the userspace listener along with
+	   the event.
+
+	   If unsure, say Y.
diff --git a/fs/notify/fanotify/Makefile b/fs/notify/fanotify/Makefile
new file mode 100644
index 000000000000..e7d39c05b0fe
--- /dev/null
+++ b/fs/notify/fanotify/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_FANOTIFY)		+= fanotify.o
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
new file mode 100644
index 000000000000..3ffb9dbcab08
--- /dev/null
+++ b/fs/notify/fanotify/fanotify.c
@@ -0,0 +1,78 @@
+#include <linux/fdtable.h>
+#include <linux/fsnotify_backend.h>
+#include <linux/init.h>
+#include <linux/kernel.h> /* UINT_MAX */
+#include <linux/types.h>
+
+#include "fanotify.h"
+
+static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
+{
+	int ret;
+
+
+	BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
+	BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
+	BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
+	BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE);
+	BUILD_BUG_ON(FAN_OPEN != FS_OPEN);
+	BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD);
+	BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW);
+
+	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
+
+	ret = fsnotify_add_notify_event(group, event, NULL, NULL);
+
+	return ret;
+}
+
+static bool fanotify_should_send_event(struct fsnotify_group *group, struct inode *inode,
+				       struct vfsmount *mnt, __u32 mask, void *data,
+				       int data_type)
+{
+	struct fsnotify_mark *fsn_mark;
+	bool send;
+
+	pr_debug("%s: group=%p inode=%p mask=%x data=%p data_type=%d\n",
+		 __func__, group, inode, mask, data, data_type);
+
+	/* sorry, fanotify only gives a damn about files and dirs */
+	if (!S_ISREG(inode->i_mode) &&
+	    !S_ISDIR(inode->i_mode))
+		return false;
+
+	/* if we don't have enough info to send an event to userspace say no */
+	if (data_type != FSNOTIFY_EVENT_PATH)
+		return false;
+
+	fsn_mark = fsnotify_find_mark(group, inode);
+	if (!fsn_mark)
+		return false;
+
+	/* if the event is for a child and this inode doesn't care about
+	 * events on the child, don't send it! */
+	if ((mask & FS_EVENT_ON_CHILD) &&
+	    !(fsn_mark->mask & FS_EVENT_ON_CHILD)) {
+		send = false;
+	} else {
+		/*
+		 * We care about children, but do we care about this particular
+		 * type of event?
+		 */
+		mask = (mask & ~FS_EVENT_ON_CHILD);
+		send = (fsn_mark->mask & mask);
+	}
+
+	/* find took a reference */
+	fsnotify_put_mark(fsn_mark);
+
+	return send;
+}
+
+const struct fsnotify_ops fanotify_fsnotify_ops = {
+	.handle_event = fanotify_handle_event,
+	.should_send_event = fanotify_should_send_event,
+	.free_group_priv = NULL,
+	.free_event_priv = NULL,
+	.freeing_mark = NULL,
+};
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
new file mode 100644
index 000000000000..50765eb30fe4
--- /dev/null
+++ b/fs/notify/fanotify/fanotify.h
@@ -0,0 +1,12 @@
+#include <linux/fanotify.h>
+#include <linux/fsnotify_backend.h>
+#include <linux/net.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+static inline bool fanotify_mask_valid(__u32 mask)
+{
+	if (mask & ~((__u32)FAN_ALL_INCOMING_EVENTS))
+		return false;
+	return true;
+}