fanotify: record name info for FAN_DIR_MODIFY event

For FAN_DIR_MODIFY event, allocate a variable size event struct to store
the dir entry name along side the directory file handle.

At this point, name info reporting is not yet implemented, so trying to
set FAN_DIR_MODIFY in mark mask will return -EINVAL.

Link: https://lore.kernel.org/r/20200319151022.31456-14-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 39 insertions, 1 deletions

diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index eecf4be3bfd1..35bfbf4a7aac 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -59,7 +59,8 @@ static inline void *fanotify_fh_buf(struct fanotify_fh *fh)
  * be freed and which concrete struct it may be cast to.
  */
 enum fanotify_event_type {
-	FANOTIFY_EVENT_TYPE_FID,
+	FANOTIFY_EVENT_TYPE_FID, /* fixed length */
+	FANOTIFY_EVENT_TYPE_FID_NAME, /* variable length */
 	FANOTIFY_EVENT_TYPE_PATH,
 	FANOTIFY_EVENT_TYPE_PATH_PERM,
 };
@@ -83,10 +84,26 @@ FANOTIFY_FE(struct fanotify_event *event)
 	return container_of(event, struct fanotify_fid_event, fae);
 }
 
+struct fanotify_name_event {
+	struct fanotify_event fae;
+	__kernel_fsid_t fsid;
+	struct fanotify_fh dir_fh;
+	u8 name_len;
+	char name[0];
+};
+
+static inline struct fanotify_name_event *
+FANOTIFY_NE(struct fanotify_event *event)
+{
+	return container_of(event, struct fanotify_name_event, fae);
+}
+
 static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
 {
 	if (event->type == FANOTIFY_EVENT_TYPE_FID)
 		return &FANOTIFY_FE(event)->fsid;
+	else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
+		return &FANOTIFY_NE(event)->fsid;
 	else
 		return NULL;
 }
@@ -100,6 +117,15 @@ static inline struct fanotify_fh *fanotify_event_object_fh(
 		return NULL;
 }
 
+static inline struct fanotify_fh *fanotify_event_dir_fh(
+						struct fanotify_event *event)
+{
+	if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
+		return &FANOTIFY_NE(event)->dir_fh;
+	else
+		return NULL;
+}
+
 static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
 {
 	struct fanotify_fh *fh = fanotify_event_object_fh(event);
@@ -107,6 +133,17 @@ static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
 	return fh ? fh->len : 0;
 }
 
+static inline bool fanotify_event_has_name(struct fanotify_event *event)
+{
+	return event->type == FANOTIFY_EVENT_TYPE_FID_NAME;
+}
+
+static inline int fanotify_event_name_len(struct fanotify_event *event)
+{
+	return fanotify_event_has_name(event) ?
+		FANOTIFY_NE(event)->name_len : 0;
+}
+
 struct fanotify_path_event {
 	struct fanotify_event fae;
 	struct path path;
@@ -169,4 +206,5 @@ static inline struct path *fanotify_event_path(struct fanotify_event *event)
 struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
 					    struct inode *inode, u32 mask,
 					    const void *data, int data_type,
+					    const struct qstr *file_name,
 					    __kernel_fsid_t *fsid);