}
/*
- * Any time a mark is getting freed we end up here.
- * The caller had better be holding a reference to this mark so we don't actually
- * do the final put under the mark->lock
+ * Remove mark from inode / vfsmount list, group list, drop inode reference
+ * if we got one.
+ *
+ * Must be called with group->mark_mutex held.
*/
-void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark,
- struct fsnotify_group *group)
+void fsnotify_detach_mark(struct fsnotify_mark *mark)
{
struct inode *inode = NULL;
+ struct fsnotify_group *group = mark->group;
BUG_ON(!mutex_is_locked(&group->mark_mutex));
spin_lock(&mark->lock);
/* something else already called this function on this mark */
- if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
+ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
spin_unlock(&mark->lock);
return;
}
- mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
inode = mark->inode;
fsnotify_destroy_vfsmount_mark(mark);
else
BUG();
+ /*
+ * Note that we didn't update flags telling whether inode cares about
+ * what's happening with children. We update these flags from
+ * __fsnotify_parent() lazily when next event happens on one of our
+ * children.
+ */
list_del_init(&mark->g_list);
if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED))
iput(inode);
- /* release lock temporarily */
- mutex_unlock(&group->mark_mutex);
+
+ atomic_dec(&group->num_marks);
+}
+
+/*
+ * Free fsnotify mark. The freeing is actually happening from a kthread which
+ * first waits for srcu period end. Caller must have a reference to the mark
+ * or be protected by fsnotify_mark_srcu.
+ */
+void fsnotify_free_mark(struct fsnotify_mark *mark)
+{
+ struct fsnotify_group *group = mark->group;
+
+ spin_lock(&mark->lock);
+ /* something else already called this function on this mark */
+ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
+ spin_unlock(&mark->lock);
+ return;
+ }
+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
+ spin_unlock(&mark->lock);
spin_lock(&destroy_lock);
list_add(&mark->g_list, &destroy_list);
spin_unlock(&destroy_lock);
wake_up(&destroy_waitq);
- /*
- * We don't necessarily have a ref on mark from caller so the above destroy
- * may have actually freed it, unless this group provides a 'freeing_mark'
- * function which must be holding a reference.
- */
/*
* Some groups like to know that marks are being freed. This is a
*/
if (group->ops->freeing_mark)
group->ops->freeing_mark(mark, group);
-
- /*
- * __fsnotify_update_child_dentry_flags(inode);
- *
- * I really want to call that, but we can't, we have no idea if the inode
- * still exists the second we drop the mark->lock.
- *
- * The next time an event arrive to this inode from one of it's children
- * __fsnotify_parent will see that the inode doesn't care about it's
- * children and will update all of these flags then. So really this
- * is just a lazy update (and could be a perf win...)
- */
-
- atomic_dec(&group->num_marks);
-
- mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
}
void fsnotify_destroy_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group)
{
mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
- fsnotify_destroy_mark_locked(mark, group);
+ fsnotify_detach_mark(mark);
mutex_unlock(&group->mark_mutex);
+ fsnotify_free_mark(mark);
}
-/*
- * Destroy all marks in the given list. The marks must be already detached from
- * the original inode / vfsmount.
- */
-void fsnotify_destroy_marks(struct list_head *to_free)
+void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock)
{
- struct fsnotify_mark *mark, *lmark;
- struct fsnotify_group *group;
-
- list_for_each_entry_safe(mark, lmark, to_free, free_list) {
- spin_lock(&mark->lock);
- fsnotify_get_group(mark->group);
- group = mark->group;
- spin_unlock(&mark->lock);
+ struct fsnotify_mark *mark;
- fsnotify_destroy_mark(mark, group);
+ while (1) {
+ /*
+ * We have to be careful since we can race with e.g.
+ * fsnotify_clear_marks_by_group() and once we drop 'lock',
+ * mark can get removed from the obj_list and destroyed. But
+ * we are holding mark reference so mark cannot be freed and
+ * calling fsnotify_destroy_mark() more than once is fine.
+ */
+ spin_lock(lock);
+ if (hlist_empty(head)) {
+ spin_unlock(lock);
+ break;
+ }
+ mark = hlist_entry(head->first, struct fsnotify_mark, obj_list);
+ /*
+ * We don't update i_fsnotify_mask / mnt_fsnotify_mask here
+ * since inode / mount is going away anyway. So just remove
+ * mark from the list.
+ */
+ hlist_del_init_rcu(&mark->obj_list);
+ fsnotify_get_mark(mark);
+ spin_unlock(lock);
+ fsnotify_destroy_mark(mark, mark->group);
fsnotify_put_mark(mark);
- fsnotify_put_group(group);
}
}
* inode->i_lock
*/
spin_lock(&mark->lock);
- mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE;
+ mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED;
fsnotify_get_group(group);
mark->group = group;
}
mark = list_first_entry(&to_free, struct fsnotify_mark, g_list);
fsnotify_get_mark(mark);
- fsnotify_destroy_mark_locked(mark, group);
+ fsnotify_detach_mark(mark);
mutex_unlock(&group->mark_mutex);
+ fsnotify_free_mark(mark);
fsnotify_put_mark(mark);
}
}
Code Review / kvmfornfv.git / blobdiff