fsnotify: fsnotify_add_notify_event should return an event
Rather than the horrific void ** argument and such just to pass the fanotify_merge event back to the caller of fsnotify_add_notify_event() have those things return an event if it was different than the event suggusted to be added. Signed-off-by: Eric Paris <eparis@redhat.com>
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5ba08e2eeb
Коммит
f70ab54cc6
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@ -30,65 +30,58 @@ static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new)
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return false;
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}
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/* Note, if we return an event in *arg that a reference is being held... */
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static int fanotify_merge(struct list_head *list,
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struct fsnotify_event *event,
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void **arg)
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/* and the list better be locked by something too! */
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static struct fsnotify_event *fanotify_merge(struct list_head *list,
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struct fsnotify_event *event)
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{
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struct fsnotify_event_holder *test_holder;
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struct fsnotify_event *test_event;
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struct fsnotify_event *test_event = NULL;
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struct fsnotify_event *new_event;
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struct fsnotify_event **return_event = (struct fsnotify_event **)arg;
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int ret = 0;
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pr_debug("%s: list=%p event=%p\n", __func__, list, event);
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*return_event = NULL;
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/* and the list better be locked by something too! */
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list_for_each_entry_reverse(test_holder, list, event_list) {
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test_event = test_holder->event;
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if (should_merge(test_event, event)) {
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fsnotify_get_event(test_event);
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*return_event = test_event;
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ret = -EEXIST;
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/* if they are exactly the same we are done */
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if (test_event->mask == event->mask)
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goto out;
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/*
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* if the refcnt == 1 this is the only queue
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* for this event and so we can update the mask
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* in place.
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*/
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if (atomic_read(&test_event->refcnt) == 1) {
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test_event->mask |= event->mask;
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goto out;
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}
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/* can't allocate memory, merge was no possible */
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new_event = fsnotify_clone_event(test_event);
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if (unlikely(!new_event)) {
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ret = 0;
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goto out;
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}
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/* we didn't return the test_event, so drop that ref */
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fsnotify_put_event(test_event);
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/* the reference we return on new_event is from clone */
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*return_event = new_event;
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/* build new event and replace it on the list */
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new_event->mask = (test_event->mask | event->mask);
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fsnotify_replace_event(test_holder, new_event);
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if (should_merge(test_holder->event, event)) {
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test_event = test_holder->event;
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break;
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}
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}
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out:
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return ret;
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if (!test_event)
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return NULL;
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fsnotify_get_event(test_event);
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/* if they are exactly the same we are done */
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if (test_event->mask == event->mask)
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return test_event;
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/*
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* if the refcnt == 2 this is the only queue
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* for this event and so we can update the mask
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* in place.
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*/
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if (atomic_read(&test_event->refcnt) == 2) {
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test_event->mask |= event->mask;
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return test_event;
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}
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new_event = fsnotify_clone_event(test_event);
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/* done with test_event */
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fsnotify_put_event(test_event);
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/* couldn't allocate memory, merge was not possible */
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if (unlikely(!new_event))
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return ERR_PTR(-ENOMEM);
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/* build new event and replace it on the list */
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new_event->mask = (test_event->mask | event->mask);
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fsnotify_replace_event(test_holder, new_event);
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/* we hold a reference on new_event from clone_event */
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return new_event;
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}
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#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
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@ -123,7 +116,7 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group,
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static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
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{
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int ret;
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int ret = 0;
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struct fsnotify_event *notify_event = NULL;
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BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
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@ -138,13 +131,9 @@ static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_e
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pr_debug("%s: group=%p event=%p\n", __func__, group, event);
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ret = fsnotify_add_notify_event(group, event, NULL, fanotify_merge,
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(void **)¬ify_event);
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/* -EEXIST means this event was merged with another, not that it was an error */
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if (ret == -EEXIST)
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ret = 0;
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if (ret)
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goto out;
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notify_event = fsnotify_add_notify_event(group, event, NULL, fanotify_merge);
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if (IS_ERR(notify_event))
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return PTR_ERR(notify_event);
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#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
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if (event->mask & FAN_ALL_PERM_EVENTS) {
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@ -155,9 +144,9 @@ static int fanotify_handle_event(struct fsnotify_group *group, struct fsnotify_e
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}
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#endif
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out:
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if (notify_event)
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fsnotify_put_event(notify_event);
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return ret;
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}
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@ -68,13 +68,11 @@ static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new
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return false;
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}
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static int inotify_merge(struct list_head *list,
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struct fsnotify_event *event,
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void **arg)
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static struct fsnotify_event *inotify_merge(struct list_head *list,
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struct fsnotify_event *event)
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{
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struct fsnotify_event_holder *last_holder;
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struct fsnotify_event *last_event;
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int ret = 0;
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/* and the list better be locked by something too */
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spin_lock(&event->lock);
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@ -82,11 +80,13 @@ static int inotify_merge(struct list_head *list,
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last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list);
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last_event = last_holder->event;
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if (event_compare(last_event, event))
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ret = -EEXIST;
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fsnotify_get_event(last_event);
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else
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last_event = NULL;
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spin_unlock(&event->lock);
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return ret;
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return last_event;
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}
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static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
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@ -96,7 +96,8 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev
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struct inode *to_tell;
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struct inotify_event_private_data *event_priv;
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struct fsnotify_event_private_data *fsn_event_priv;
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int wd, ret;
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struct fsnotify_event *added_event;
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int wd, ret = 0;
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pr_debug("%s: group=%p event=%p to_tell=%p mask=%x\n", __func__, group,
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event, event->to_tell, event->mask);
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@ -120,14 +121,13 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev
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fsn_event_priv->group = group;
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event_priv->wd = wd;
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ret = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge, NULL);
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if (ret) {
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added_event = fsnotify_add_notify_event(group, event, fsn_event_priv, inotify_merge);
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if (added_event) {
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inotify_free_event_priv(fsn_event_priv);
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/* EEXIST says we tail matched, EOVERFLOW isn't something
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* to report up the stack. */
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if ((ret == -EEXIST) ||
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(ret == -EOVERFLOW))
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ret = 0;
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if (!IS_ERR(added_event))
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fsnotify_put_event(added_event);
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else
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ret = PTR_ERR(added_event);
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}
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if (fsn_mark->mask & IN_ONESHOT)
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@ -516,7 +516,7 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark,
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struct fsnotify_group *group)
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{
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struct inotify_inode_mark *i_mark;
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struct fsnotify_event *ignored_event;
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struct fsnotify_event *ignored_event, *notify_event;
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struct inotify_event_private_data *event_priv;
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struct fsnotify_event_private_data *fsn_event_priv;
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int ret;
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@ -538,9 +538,14 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark *fsn_mark,
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fsn_event_priv->group = group;
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event_priv->wd = i_mark->wd;
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ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv, NULL, NULL);
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if (ret)
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notify_event = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv, NULL);
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if (notify_event) {
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if (IS_ERR(notify_event))
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ret = PTR_ERR(notify_event);
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else
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fsnotify_put_event(notify_event);
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inotify_free_event_priv(fsn_event_priv);
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}
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skip_send_ignore:
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@ -137,16 +137,14 @@ struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnot
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* event off the queue to deal with. If the event is successfully added to the
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* group's notification queue, a reference is taken on event.
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*/
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int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event,
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struct fsnotify_event_private_data *priv,
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int (*merge)(struct list_head *,
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struct fsnotify_event *,
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void **arg),
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void **arg)
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struct fsnotify_event *fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event,
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struct fsnotify_event_private_data *priv,
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struct fsnotify_event *(*merge)(struct list_head *,
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struct fsnotify_event *))
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{
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struct fsnotify_event *return_event = NULL;
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struct fsnotify_event_holder *holder = NULL;
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struct list_head *list = &group->notification_list;
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int rc = 0;
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pr_debug("%s: group=%p event=%p priv=%p\n", __func__, group, event, priv);
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@ -162,27 +160,37 @@ int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_even
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alloc_holder:
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holder = fsnotify_alloc_event_holder();
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if (!holder)
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return -ENOMEM;
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return ERR_PTR(-ENOMEM);
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}
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mutex_lock(&group->notification_mutex);
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if (group->q_len >= group->max_events) {
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event = q_overflow_event;
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rc = -EOVERFLOW;
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/*
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* we need to return the overflow event
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* which means we need a ref
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*/
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fsnotify_get_event(event);
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return_event = event;
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/* sorry, no private data on the overflow event */
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priv = NULL;
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}
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if (!list_empty(list) && merge) {
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int ret;
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struct fsnotify_event *tmp;
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ret = merge(list, event, arg);
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if (ret) {
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tmp = merge(list, event);
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if (tmp) {
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mutex_unlock(&group->notification_mutex);
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if (return_event)
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fsnotify_put_event(return_event);
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if (holder != &event->holder)
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fsnotify_destroy_event_holder(holder);
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return ret;
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return tmp;
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}
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}
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@ -197,6 +205,12 @@ alloc_holder:
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* event holder was used, go back and get a new one */
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spin_unlock(&event->lock);
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mutex_unlock(&group->notification_mutex);
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if (return_event) {
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fsnotify_put_event(return_event);
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return_event = NULL;
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}
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goto alloc_holder;
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}
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@ -211,7 +225,7 @@ alloc_holder:
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mutex_unlock(&group->notification_mutex);
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wake_up(&group->notification_waitq);
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return rc;
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return return_event;
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}
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/*
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@ -379,13 +379,11 @@ extern struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struc
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struct fsnotify_event *event);
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/* attach the event to the group notification queue */
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extern int fsnotify_add_notify_event(struct fsnotify_group *group,
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struct fsnotify_event *event,
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struct fsnotify_event_private_data *priv,
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int (*merge)(struct list_head *,
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struct fsnotify_event *,
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void **),
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void **arg);
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extern struct fsnotify_event *fsnotify_add_notify_event(struct fsnotify_group *group,
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struct fsnotify_event *event,
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struct fsnotify_event_private_data *priv,
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struct fsnotify_event *(*merge)(struct list_head *,
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struct fsnotify_event *));
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/* true if the group notification queue is empty */
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extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
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/* return, but do not dequeue the first event on the notification queue */
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