[PATCH 5/8] fanotify: merge notification events with different masks
From: Eric Paris <eparis@redhat.com>
Date: 2009-09-11 05:26:36
Also in:
linux-fsdevel, lkml
Subsystem:
fanotify, filesystems (vfs and infrastructure), fsnotify: filesystem notification infrastructure, the rest · Maintainers:
Jan Kara, Alexander Viro, Christian Brauner, Linus Torvalds
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@redhat.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 f054300..40ee137 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;