[PATCH v5 19/22] fanotify: report events with parent dir fid to sb/mount/non-dir marks

From: Amir Goldstein <amir73il@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org
Subject: [PATCH v5 19/22] fanotify: report events with parent dir fid to sb/mount/non-dir marks
Date: Thu, 16 Jul 2020 11:42:27 +0300	[thread overview]
Message-ID: <20200716084230.30611-20-amir73il@gmail.com> (raw)
In-Reply-To: <20200716084230.30611-1-amir73il@gmail.com>

In a group with flag FAN_REPORT_DIR_FID, when adding an inode mark with
FAN_EVENT_ON_CHILD, events on non-directory children are reported with
the fid of the parent.

When adding a filesystem or mount mark or mark on a non-dir inode, we
want to report events that are "possible on child" (e.g. open/close)
also with fid of the parent, as if the victim inode's parent is
interested in events "on child".

Some events, currently only FAN_MOVE_SELF, should be reported to a
sb/mount/non-dir mark with parent fid even though they are not
reported to a watching parent.

To get the desired behavior we set the flag FAN_EVENT_ON_CHILD on
all the sb/mount/non-dir mark masks in a group with FAN_REPORT_DIR_FID.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/notify/fanotify/fanotify.c      | 3 +--
 fs/notify/fanotify/fanotify_user.c | 7 +++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 4cbdb40e0d54..09331b0acaf2 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -272,8 +272,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
 		 */
 		if (event_mask & FS_EVENT_ON_CHILD &&
 		    type != FSNOTIFY_OBJ_TYPE_CHILD &&
-		    (type != FSNOTIFY_OBJ_TYPE_INODE ||
-		     !(mark->mask & FS_EVENT_ON_CHILD)))
+		    !(mark->mask & FS_EVENT_ON_CHILD))
 			continue;
 
 		marks_mask |= mark->mask;
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index e494400711c9..7caa64d028ba 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1220,6 +1220,13 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	if (mnt || !S_ISDIR(inode->i_mode)) {
 		mask &= ~FAN_EVENT_ON_CHILD;
 		umask = FAN_EVENT_ON_CHILD;
+		/*
+		 * If group needs to report parent fid, register for getting
+		 * events with parent/name info for non-directory.
+		 */
+		if ((fid_mode & FAN_REPORT_DIR_FID) &&
+		    (flags & FAN_MARK_ADD) && !ignored)
+			mask |= FAN_EVENT_ON_CHILD;
 	}
 
 	/* create/update an inode mark */
-- 
2.17.1

