[PATCH v5 13/17] fsnotify: report FS_ISDIR flag with MOVE_SELF and DELETE_SELF events

[Amir Goldstein <amir73il@gmail.com>]

We need to report FS_ISDIR flag with MOVE_SELF and DELETE_SELF events
for fanotify, because fanotify API requires the user to explicitly
request events on directories by FAN_ONDIR flag.

inotify never reported IN_ISDIR with those events. It looks like an
oversight, but to avoid the risk of breaking existing inotify programs,
mask the FS_ISDIR flag out when reprting those events to inotify backend.

We also add the FS_ISDIR flag with FS_ATTRIB event in the case of rename
over an empty target directory. inotify did not report IN_ISDIR in this
case, but it normally does report IN_ISDIR along with IN_ATTRIB event,
so in this case, we do not mask out the FS_ISDIR flag.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/notify/inotify/inotify_fsnotify.c |  9 +++++++++
 include/linux/fsnotify.h             | 23 +++++++++++++++++++----
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index fe97299975f2..ff30abd6a49b 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -113,6 +113,15 @@ int inotify_handle_event(struct fsnotify_group *group,
 		return -ENOMEM;
 	}
 
+	/*
+	 * We now report FS_ISDIR flag with MOVE_SELF and DELETE_SELF events
+	 * for fanotify. inotify never reported IN_ISDIR with those events.
+	 * It looks like an oversight, but to avoid the risk of breaking
+	 * existing inotify programs, mask the flag out from those events.
+	 */
+	if (mask & (IN_MOVE_SELF | IN_DELETE_SELF))
+		mask &= ~IN_ISDIR;
+
 	fsn_event = &event->fse;
 	fsnotify_init_event(fsn_event, inode);
 	event->mask = mask;
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 116907928c7f..bec2e8f66012 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -87,7 +87,12 @@ static inline int fsnotify_perm(struct file *file, int mask)
  */
 static inline void fsnotify_link_count(struct inode *inode)
 {
-	fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+	__u32 mask = FS_ATTRIB;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= FS_ISDIR;
+
+	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 }
 
 /*
@@ -95,12 +100,14 @@ static inline void fsnotify_link_count(struct inode *inode)
  */
 static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 				 const unsigned char *old_name,
-				 int isdir, struct inode *target, struct dentry *moved)
+				 int isdir, struct inode *target,
+				 struct dentry *moved)
 {
 	struct inode *source = moved->d_inode;
 	u32 fs_cookie = fsnotify_get_cookie();
 	__u32 old_dir_mask = FS_MOVED_FROM;
 	__u32 new_dir_mask = FS_MOVED_TO;
+	__u32 mask = FS_MOVE_SELF;
 	const unsigned char *new_name = moved->d_name.name;
 
 	if (old_dir == new_dir)
@@ -111,6 +118,9 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 		new_dir_mask |= FS_ISDIR;
 	}
 
+	if (d_is_dir(moved))
+		mask |= FS_ISDIR;
+
 	fsnotify(old_dir, old_dir_mask, source, FSNOTIFY_EVENT_INODE, old_name,
 		 fs_cookie);
 	fsnotify(new_dir, new_dir_mask, source, FSNOTIFY_EVENT_INODE, new_name,
@@ -120,7 +130,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 		fsnotify_link_count(target);
 
 	if (source)
-		fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+		fsnotify(source, mask, source, FSNOTIFY_EVENT_INODE, NULL, 0);
 	audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
 }
 
@@ -197,7 +207,12 @@ static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
  */
 static inline void fsnotify_inoderemove(struct inode *inode)
 {
-	fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+	__u32 mask = FS_DELETE_SELF;
+
+	if (S_ISDIR(inode->i_mode))
+		mask |= FS_ISDIR;
+
+	fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
 	__fsnotify_inode_delete(inode);
 }
 
-- 
2.17.1