[PATCH v2 9/9] fanotify: wire up FAN_RENAME event

[Amir Goldstein <amir73il@xxxxxxxxx>]

FAN_RENAME is the successor of FAN_MOVED_FROM and FAN_MOVED_TO
and can be used to get the old and new parent+name information in
a single event.

FAN_MOVED_FROM and FAN_MOVED_TO are still supported for backward
compatibility, but it makes little sense to use them together with
FAN_RENAME in the same group.

FAN_RENAME uses special info type records to report the old and
new parent+name, so reporting only old and new parent id is less
useful and was not implemented.
Therefore, FAN_REANAME requires a group with flag FAN_REPORT_NAME.

Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
 fs/notify/fanotify/fanotify.c      | 2 +-
 fs/notify/fanotify/fanotify_user.c | 8 ++++++++
 include/linux/fanotify.h           | 3 ++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 4f06b17e209d..072fb0f0c941 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -947,7 +947,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
 	BUILD_BUG_ON(FAN_FS_ERROR != FS_ERROR);
 	BUILD_BUG_ON(FAN_RENAME != FS_RENAME);
 
-	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 20);
+	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 21);
 
 	mask = fanotify_group_event_mask(group, iter_info, mask, data,
 					 data_type, dir);
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 5ec60db3cfbb..02b5b63c6582 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1587,6 +1587,14 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	    (!fid_mode || mark_type == FAN_MARK_MOUNT))
 		goto fput_and_out;
 
+	/*
+	 * FAN_RENAME uses special info type records to report the old and
+	 * new parent+name.  Reporting only old and new parent id is less
+	 * useful and was not implemented.
+	 */
+	if (mask & FAN_RENAME && !(fid_mode & FAN_REPORT_NAME))
+		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 376e050e6f38..3afdf339d53c 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -82,7 +82,8 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
  * 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)
+#define FANOTIFY_DIRENT_EVENTS	(FAN_MOVE | FAN_CREATE | FAN_DELETE | \
+				 FAN_RENAME)
 
 /* Events that can be reported with event->fd */
 #define FANOTIFY_FD_EVENTS (FANOTIFY_PATH_EVENTS | FANOTIFY_PERM_EVENTS)
-- 
2.33.1