linux-kernel - [PATCH 6/9] fanotify: merge notification events with different masks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090828185618.8014.55255.stgit@paris.rdu.redhat.com>
Date:	Fri, 28 Aug 2009 14:56:19 -0400
From:	Eric Paris <eparis@...hat.com>
To:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	netdev@...r.kernel.org
Cc:	davem@...emloft.net, viro@...iv.linux.org.uk, alan@...ux.intel.com,
	hch@...radead.org
Subject: [PATCH 6/9] fanotify: merge notification events with different masks

Instead of just merging fanotify events if they are exactly the same, merge
notification events with different masks.  To do this we have to clone the
old event, update the mask in the new event with the new merged mask, and
put the new event in place of the old event.

Signed-off-by: Eric Paris <eparis@...hat.com>
---

 fs/notify/fanotify/fanotify.c |   24 ++++++++++++++++++------
 1 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index caf34bb..e8e56cb 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -10,8 +10,7 @@
 
 static bool try_merge(struct fsnotify_event *old, struct fsnotify_event *new)
 {
-	if ((old->mask == new->mask) &&
-	    (old->to_tell == new->to_tell) &&
+	if ((old->to_tell == new->to_tell) &&
 	    (old->data_type == new->data_type)) {
 		switch (old->data_type) {
 		case (FSNOTIFY_EVENT_PATH):
@@ -29,15 +28,28 @@ static bool try_merge(struct fsnotify_event *old, struct fsnotify_event *new)
 
 static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
 {
-	struct fsnotify_event_holder *holder;
+	struct fsnotify_event_holder *test_holder, *prev;
 	struct fsnotify_event *test_event;
+	struct fsnotify_event *new_event;
+	int ret;
 
 	/* and the list better be locked by something too! */
 
-	list_for_each_entry_reverse(holder, list, event_list) {
-		test_event = holder->event;
-		if (try_merge(test_event, event))
+	list_for_each_entry_safe_reverse(test_holder, prev, list, event_list) {
+		test_event = test_holder->event;
+		if (try_merge(test_event, event)) {
+			if (test_event->mask == event->mask)
+				return -EEXIST;
+			new_event = fsnotify_clone_event(test_event);
+			if (!new_event)
+				return 0;
+			new_event->mask = (test_event->mask | event->mask);
+			ret = fsnotify_replace_event(test_holder, new_event);
+			fsnotify_put_event(new_event); /* matches the ref from clone */
+			if (ret)
+				return ret;
 			return -EEXIST;
+		}
 	}
 
 	return 0;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/