[PATCH v5 16/17] fanotify: add support for create/attrib/move/delete events

[Amir Goldstein <amir73il@gmail.com>]

Add support for events with data type FSNOTIFY_EVENT_INODE
(e.g. create/attrib/move/delete) for inode and filesystem mark types.

The "inode" events do not carry enough information (i.e. path) to
report event->fd, so we do not allow setting a mask for those events
unless group supports reporting fid.

The "inode" events are not supported on a mount mark, because they do
not carry enough information (i.e. path) to be filtered by mount point.

The "dirent" events (create/move/delete) report the fid of the parent
directory where events took place without specifying the filename of the
child. In the future, fanotify may get support for reporting filename
information for those events.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/notify/fanotify/fanotify.c      |  9 ++++++++-
 fs/notify/fanotify/fanotify_user.c | 12 ++++++++++++
 include/linux/fanotify.h           | 22 ++++++++++++++++++++--
 include/uapi/linux/fanotify.h      |  8 ++++++++
 4 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index e3ca1632feb8..4ba9c2233965 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -315,9 +315,16 @@ static int fanotify_handle_event(struct fsnotify_group *group,
 
 	BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
 	BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
+	BUILD_BUG_ON(FAN_ATTRIB != FS_ATTRIB);
 	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_MOVED_TO != FS_MOVED_TO);
+	BUILD_BUG_ON(FAN_MOVED_FROM != FS_MOVED_FROM);
+	BUILD_BUG_ON(FAN_CREATE != FS_CREATE);
+	BUILD_BUG_ON(FAN_DELETE != FS_DELETE);
+	BUILD_BUG_ON(FAN_DELETE_SELF != FS_DELETE_SELF);
+	BUILD_BUG_ON(FAN_MOVE_SELF != FS_MOVE_SELF);
 	BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD);
 	BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW);
 	BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM);
@@ -326,7 +333,7 @@ static int fanotify_handle_event(struct fsnotify_group *group,
 	BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
 	BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
 
-	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 12);
+	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
 
 	mask = fanotify_group_event_mask(group, iter_info, mask, data,
 					 data_type);
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 8ac3ebc7b5ed..4ef6002072cc 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -976,6 +976,18 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	    group->priority == FS_PRIO_0)
 		goto fput_and_out;
 
+	/*
+	 * Events with data type inode do not carry enough information to report
+	 * event->fd, so we do not allow setting a mask for inode events unless
+	 * group supports reporting fid.
+	 * inode events are not supported on a mount mark, because they do not
+	 * carry enough information (i.e. path) to be filtered by mount point.
+	 */
+	if (mask & FANOTIFY_INODE_EVENTS &&
+	    (!FAN_GROUP_FLAG(group, FAN_REPORT_FID) ||
+	     mark_type == FAN_MARK_MOUNT))
+		goto fput_and_out;
+
 	if (flags & FAN_MARK_FLUSH) {
 		ret = 0;
 		if (mark_type == FAN_MARK_MOUNT)
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index f59be967f72b..e9d45387089f 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -35,10 +35,28 @@
 				 FAN_MARK_IGNORED_SURV_MODIFY | \
 				 FAN_MARK_FLUSH)
 
-/* Events that user can request to be notified on */
-#define FANOTIFY_EVENTS		(FAN_ACCESS | FAN_MODIFY | \
+/*
+ * Events that can be reported with data type FSNOTIFY_EVENT_PATH.
+ * Note that FAN_MODIFY can also be reported with data type
+ * FSNOTIFY_EVENT_INODE.
+ */
+#define FANOTIFY_PATH_EVENTS	(FAN_ACCESS | FAN_MODIFY | \
 				 FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
 
+/*
+ * Directory entry modification events - reported only to directory
+ * where entry is modified and not to a watching parent.
+ */
+#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)
+
+/* Events that user can request to be notified on */
+#define FANOTIFY_EVENTS		(FANOTIFY_PATH_EVENTS | \
+				 FANOTIFY_INODE_EVENTS)
+
 /* Events that require a permission response from user */
 #define FANOTIFY_PERM_EVENTS	(FAN_OPEN_PERM | FAN_ACCESS_PERM | \
 				 FAN_OPEN_EXEC_PERM)
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 959ae2bdc7ca..b9effa6f8503 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -7,9 +7,16 @@
 /* the following events that user-space can register for */
 #define FAN_ACCESS		0x00000001	/* File was accessed */
 #define FAN_MODIFY		0x00000002	/* File was modified */
+#define FAN_ATTRIB		0x00000004	/* Metadata changed */
 #define FAN_CLOSE_WRITE		0x00000008	/* Writtable file closed */
 #define FAN_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
 #define FAN_OPEN		0x00000020	/* File was opened */
+#define FAN_MOVED_FROM		0x00000040	/* File was moved from X */
+#define FAN_MOVED_TO		0x00000080	/* File was moved to Y */
+#define FAN_CREATE		0x00000100	/* Subfile was created */
+#define FAN_DELETE		0x00000200	/* Subfile was deleted */
+#define FAN_DELETE_SELF		0x00000400	/* Self was deleted */
+#define FAN_MOVE_SELF		0x00000800	/* Self was moved */
 #define FAN_OPEN_EXEC		0x00001000	/* File was opened for exec */
 
 #define FAN_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
@@ -24,6 +31,7 @@
 
 /* helper events */
 #define FAN_CLOSE		(FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
+#define FAN_MOVE		(FAN_MOVED_FROM | FAN_MOVED_TO) /* moves */
 
 /* flags used for fanotify_init() */
 #define FAN_CLOEXEC		0x00000001
-- 
2.17.1