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- #include <linux/fs.h>
- #include <linux/init.h>
- #include <linux/kernel.h>
- #include <linux/list.h>
- #include <linux/module.h>
- #include <linux/mount.h>
- #include <linux/mutex.h>
- #include <linux/namei.h>
- #include <linux/path.h>
- #include <linux/slab.h>
- #include <linux/spinlock.h>
- #include <linux/atomic.h>
- #include <linux/fsnotify_backend.h>
- #include "fsnotify.h"
- static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0);
- u32 fsnotify_get_cookie(void)
- {
- return atomic_inc_return(&fsnotify_sync_cookie);
- }
- EXPORT_SYMBOL_GPL(fsnotify_get_cookie);
- void fsnotify_destroy_event(struct fsnotify_group *group,
- struct fsnotify_event *event)
- {
-
- if (!event || event == group->overflow_event)
- return;
-
- if (!list_empty(&event->list)) {
- spin_lock(&group->notification_lock);
- WARN_ON(!list_empty(&event->list));
- spin_unlock(&group->notification_lock);
- }
- group->ops->free_event(group, event);
- }
- int fsnotify_insert_event(struct fsnotify_group *group,
- struct fsnotify_event *event,
- int (*merge)(struct fsnotify_group *,
- struct fsnotify_event *),
- void (*insert)(struct fsnotify_group *,
- struct fsnotify_event *))
- {
- int ret = 0;
- struct list_head *list = &group->notification_list;
- pr_debug("%s: group=%p event=%p\n", __func__, group, event);
- spin_lock(&group->notification_lock);
- if (group->shutdown) {
- spin_unlock(&group->notification_lock);
- return 2;
- }
- if (event == group->overflow_event ||
- group->q_len >= group->max_events) {
- ret = 2;
-
- if (!list_empty(&group->overflow_event->list)) {
- spin_unlock(&group->notification_lock);
- return ret;
- }
- event = group->overflow_event;
- goto queue;
- }
- if (!list_empty(list) && merge) {
- ret = merge(group, event);
- if (ret) {
- spin_unlock(&group->notification_lock);
- return ret;
- }
- }
- queue:
- group->q_len++;
- list_add_tail(&event->list, list);
- if (insert)
- insert(group, event);
- spin_unlock(&group->notification_lock);
- wake_up(&group->notification_waitq);
- kill_fasync(&group->fsn_fa, SIGIO, POLL_IN);
- return ret;
- }
- void fsnotify_remove_queued_event(struct fsnotify_group *group,
- struct fsnotify_event *event)
- {
- assert_spin_locked(&group->notification_lock);
-
- list_del_init(&event->list);
- group->q_len--;
- }
- struct fsnotify_event *fsnotify_peek_first_event(struct fsnotify_group *group)
- {
- assert_spin_locked(&group->notification_lock);
- if (fsnotify_notify_queue_is_empty(group))
- return NULL;
- return list_first_entry(&group->notification_list,
- struct fsnotify_event, list);
- }
- struct fsnotify_event *fsnotify_remove_first_event(struct fsnotify_group *group)
- {
- struct fsnotify_event *event = fsnotify_peek_first_event(group);
- if (!event)
- return NULL;
- pr_debug("%s: group=%p event=%p\n", __func__, group, event);
- fsnotify_remove_queued_event(group, event);
- return event;
- }
- void fsnotify_flush_notify(struct fsnotify_group *group)
- {
- struct fsnotify_event *event;
- spin_lock(&group->notification_lock);
- while (!fsnotify_notify_queue_is_empty(group)) {
- event = fsnotify_remove_first_event(group);
- spin_unlock(&group->notification_lock);
- fsnotify_destroy_event(group, event);
- spin_lock(&group->notification_lock);
- }
- spin_unlock(&group->notification_lock);
- }
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