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@@ -33,7 +33,7 @@
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*
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* group->mark_mutex
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* mark->lock
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- * inode->i_lock
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+ * mark->connector->lock
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*
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* group->mark_mutex protects the marks_list anchored inside a given group and
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* each mark is hooked via the g_list. It also protects the groups private
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@@ -44,14 +44,22 @@
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* is assigned to as well as the access to a reference of the inode/vfsmount
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* that is being watched by the mark.
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*
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- * inode->i_lock protects the i_fsnotify_marks list anchored inside a
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- * given inode and each mark is hooked via the i_list. (and sorta the
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- * free_i_list)
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+ * mark->connector->lock protects the list of marks anchored inside an
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+ * inode / vfsmount and each mark is hooked via the i_list.
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*
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+ * A list of notification marks relating to inode / mnt is contained in
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+ * fsnotify_mark_connector. That structure is alive as long as there are any
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+ * marks in the list and is also protected by fsnotify_mark_srcu. A mark gets
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+ * detached from fsnotify_mark_connector when last reference to the mark is
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+ * dropped. Thus having mark reference is enough to protect mark->connector
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+ * pointer and to make sure fsnotify_mark_connector cannot disappear. Also
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+ * because we remove mark from g_list before dropping mark reference associated
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+ * with that, any mark found through g_list is guaranteed to have
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+ * mark->connector set until we drop group->mark_mutex.
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*
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* LIFETIME:
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* Inode marks survive between when they are added to an inode and when their
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- * refcnt==0.
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+ * refcnt==0. Marks are also protected by fsnotify_mark_srcu.
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*
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* The inode mark can be cleared for a number of different reasons including:
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* - The inode is unlinked for the last time. (fsnotify_inode_remove)
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@@ -61,17 +69,6 @@
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* - The fsnotify_group associated with the mark is going away and all such marks
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* need to be cleaned up. (fsnotify_clear_marks_by_group)
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*
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- * Worst case we are given an inode and need to clean up all the marks on that
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- * inode. We take i_lock and walk the i_fsnotify_marks safely. For each
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- * mark on the list we take a reference (so the mark can't disappear under us).
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- * We remove that mark form the inode's list of marks and we add this mark to a
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- * private list anchored on the stack using i_free_list; we walk i_free_list
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- * and before we destroy the mark we make sure that we dont race with a
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- * concurrent destroy_group by getting a ref to the marks group and taking the
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- * groups mutex.
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-
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- * Very similarly for freeing by group, except we use free_g_list.
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- *
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* This has the very interesting property of being able to run concurrently with
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* any (or all) other directions.
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*/
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@@ -94,94 +91,281 @@
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#define FSNOTIFY_REAPER_DELAY (1) /* 1 jiffy */
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struct srcu_struct fsnotify_mark_srcu;
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+struct kmem_cache *fsnotify_mark_connector_cachep;
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+
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static DEFINE_SPINLOCK(destroy_lock);
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static LIST_HEAD(destroy_list);
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+static struct fsnotify_mark_connector *connector_destroy_list;
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static void fsnotify_mark_destroy_workfn(struct work_struct *work);
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static DECLARE_DELAYED_WORK(reaper_work, fsnotify_mark_destroy_workfn);
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+static void fsnotify_connector_destroy_workfn(struct work_struct *work);
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+static DECLARE_WORK(connector_reaper_work, fsnotify_connector_destroy_workfn);
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+
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void fsnotify_get_mark(struct fsnotify_mark *mark)
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{
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+ WARN_ON_ONCE(!atomic_read(&mark->refcnt));
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atomic_inc(&mark->refcnt);
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}
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-void fsnotify_put_mark(struct fsnotify_mark *mark)
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+/*
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+ * Get mark reference when we found the mark via lockless traversal of object
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+ * list. Mark can be already removed from the list by now and on its way to be
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+ * destroyed once SRCU period ends.
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+ */
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+static bool fsnotify_get_mark_safe(struct fsnotify_mark *mark)
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{
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- if (atomic_dec_and_test(&mark->refcnt)) {
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- if (mark->group)
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- fsnotify_put_group(mark->group);
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- mark->free_mark(mark);
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- }
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+ return atomic_inc_not_zero(&mark->refcnt);
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}
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-/* Calculate mask of events for a list of marks */
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-u32 fsnotify_recalc_mask(struct hlist_head *head)
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+static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
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{
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u32 new_mask = 0;
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struct fsnotify_mark *mark;
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- hlist_for_each_entry(mark, head, obj_list)
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- new_mask |= mark->mask;
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- return new_mask;
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+ assert_spin_locked(&conn->lock);
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+ hlist_for_each_entry(mark, &conn->list, obj_list) {
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+ if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)
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+ new_mask |= mark->mask;
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+ }
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+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
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+ conn->inode->i_fsnotify_mask = new_mask;
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+ else if (conn->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT)
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+ real_mount(conn->mnt)->mnt_fsnotify_mask = new_mask;
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}
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/*
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- * Remove mark from inode / vfsmount list, group list, drop inode reference
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- * if we got one.
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- *
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- * Must be called with group->mark_mutex held.
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+ * Calculate mask of events for a list of marks. The caller must make sure
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+ * connector and connector->inode cannot disappear under us. Callers achieve
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+ * this by holding a mark->lock or mark->group->mark_mutex for a mark on this
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+ * list.
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*/
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-void fsnotify_detach_mark(struct fsnotify_mark *mark)
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+void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
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+{
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+ if (!conn)
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+ return;
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+
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+ spin_lock(&conn->lock);
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+ __fsnotify_recalc_mask(conn);
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+ spin_unlock(&conn->lock);
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+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
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+ __fsnotify_update_child_dentry_flags(conn->inode);
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+}
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+
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+/* Free all connectors queued for freeing once SRCU period ends */
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+static void fsnotify_connector_destroy_workfn(struct work_struct *work)
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+{
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+ struct fsnotify_mark_connector *conn, *free;
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+
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+ spin_lock(&destroy_lock);
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+ conn = connector_destroy_list;
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+ connector_destroy_list = NULL;
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+ spin_unlock(&destroy_lock);
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+
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+ synchronize_srcu(&fsnotify_mark_srcu);
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+ while (conn) {
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+ free = conn;
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+ conn = conn->destroy_next;
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+ kmem_cache_free(fsnotify_mark_connector_cachep, free);
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+ }
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+}
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+
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+static struct inode *fsnotify_detach_connector_from_object(
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+ struct fsnotify_mark_connector *conn)
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{
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struct inode *inode = NULL;
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+
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+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE) {
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+ inode = conn->inode;
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+ rcu_assign_pointer(inode->i_fsnotify_marks, NULL);
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+ inode->i_fsnotify_mask = 0;
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+ conn->inode = NULL;
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+ conn->flags &= ~FSNOTIFY_OBJ_TYPE_INODE;
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+ } else if (conn->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT) {
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+ rcu_assign_pointer(real_mount(conn->mnt)->mnt_fsnotify_marks,
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+ NULL);
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+ real_mount(conn->mnt)->mnt_fsnotify_mask = 0;
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+ conn->mnt = NULL;
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+ conn->flags &= ~FSNOTIFY_OBJ_TYPE_VFSMOUNT;
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+ }
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+
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+ return inode;
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+}
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+
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+static void fsnotify_final_mark_destroy(struct fsnotify_mark *mark)
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+{
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struct fsnotify_group *group = mark->group;
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- BUG_ON(!mutex_is_locked(&group->mark_mutex));
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+ if (WARN_ON_ONCE(!group))
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+ return;
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+ group->ops->free_mark(mark);
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+ fsnotify_put_group(group);
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+}
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- spin_lock(&mark->lock);
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+void fsnotify_put_mark(struct fsnotify_mark *mark)
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+{
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+ struct fsnotify_mark_connector *conn;
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+ struct inode *inode = NULL;
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+ bool free_conn = false;
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- /* something else already called this function on this mark */
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- if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
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- spin_unlock(&mark->lock);
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+ /* Catch marks that were actually never attached to object */
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+ if (!mark->connector) {
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+ if (atomic_dec_and_test(&mark->refcnt))
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+ fsnotify_final_mark_destroy(mark);
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return;
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}
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- mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
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+ /*
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+ * We have to be careful so that traversals of obj_list under lock can
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+ * safely grab mark reference.
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+ */
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+ if (!atomic_dec_and_lock(&mark->refcnt, &mark->connector->lock))
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+ return;
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- if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
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- inode = mark->inode;
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- fsnotify_destroy_inode_mark(mark);
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- } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT)
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- fsnotify_destroy_vfsmount_mark(mark);
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- else
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- BUG();
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+ conn = mark->connector;
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+ hlist_del_init_rcu(&mark->obj_list);
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+ if (hlist_empty(&conn->list)) {
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+ inode = fsnotify_detach_connector_from_object(conn);
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+ free_conn = true;
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+ } else {
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+ __fsnotify_recalc_mask(conn);
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+ }
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+ mark->connector = NULL;
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+ spin_unlock(&conn->lock);
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+
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+ iput(inode);
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+
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+ if (free_conn) {
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+ spin_lock(&destroy_lock);
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+ conn->destroy_next = connector_destroy_list;
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+ connector_destroy_list = conn;
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+ spin_unlock(&destroy_lock);
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+ queue_work(system_unbound_wq, &connector_reaper_work);
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+ }
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/*
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* Note that we didn't update flags telling whether inode cares about
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* what's happening with children. We update these flags from
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* __fsnotify_parent() lazily when next event happens on one of our
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* children.
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*/
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+ spin_lock(&destroy_lock);
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+ list_add(&mark->g_list, &destroy_list);
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+ spin_unlock(&destroy_lock);
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+ queue_delayed_work(system_unbound_wq, &reaper_work,
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+ FSNOTIFY_REAPER_DELAY);
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+}
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- list_del_init(&mark->g_list);
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+bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
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+{
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+ struct fsnotify_group *group;
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- spin_unlock(&mark->lock);
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+ if (WARN_ON_ONCE(!iter_info->inode_mark && !iter_info->vfsmount_mark))
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+ return false;
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+
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+ if (iter_info->inode_mark)
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+ group = iter_info->inode_mark->group;
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+ else
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+ group = iter_info->vfsmount_mark->group;
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+
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+ /*
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+ * Since acquisition of mark reference is an atomic op as well, we can
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+ * be sure this inc is seen before any effect of refcount increment.
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+ */
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+ atomic_inc(&group->user_waits);
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+
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+ if (iter_info->inode_mark) {
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+ /* This can fail if mark is being removed */
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+ if (!fsnotify_get_mark_safe(iter_info->inode_mark))
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+ goto out_wait;
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+ }
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+ if (iter_info->vfsmount_mark) {
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+ if (!fsnotify_get_mark_safe(iter_info->vfsmount_mark))
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+ goto out_inode;
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+ }
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- if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED))
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- iput(inode);
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+ /*
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+ * Now that both marks are pinned by refcount in the inode / vfsmount
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+ * lists, we can drop SRCU lock, and safely resume the list iteration
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+ * once userspace returns.
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+ */
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+ srcu_read_unlock(&fsnotify_mark_srcu, iter_info->srcu_idx);
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+
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+ return true;
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+out_inode:
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+ if (iter_info->inode_mark)
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+ fsnotify_put_mark(iter_info->inode_mark);
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+out_wait:
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+ if (atomic_dec_and_test(&group->user_waits) && group->shutdown)
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+ wake_up(&group->notification_waitq);
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+ return false;
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+}
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+
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+void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info)
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+{
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+ struct fsnotify_group *group = NULL;
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+
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+ iter_info->srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
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+ if (iter_info->inode_mark) {
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+ group = iter_info->inode_mark->group;
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+ fsnotify_put_mark(iter_info->inode_mark);
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+ }
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+ if (iter_info->vfsmount_mark) {
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+ group = iter_info->vfsmount_mark->group;
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+ fsnotify_put_mark(iter_info->vfsmount_mark);
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+ }
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+ /*
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+ * We abuse notification_waitq on group shutdown for waiting for all
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+ * marks pinned when waiting for userspace.
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+ */
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+ if (atomic_dec_and_test(&group->user_waits) && group->shutdown)
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+ wake_up(&group->notification_waitq);
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+}
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+
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+/*
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+ * Mark mark as detached, remove it from group list. Mark still stays in object
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+ * list until its last reference is dropped. Note that we rely on mark being
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+ * removed from group list before corresponding reference to it is dropped. In
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+ * particular we rely on mark->connector being valid while we hold
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+ * group->mark_mutex if we found the mark through g_list.
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+ *
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+ * Must be called with group->mark_mutex held. The caller must either hold
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+ * reference to the mark or be protected by fsnotify_mark_srcu.
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+ */
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+void fsnotify_detach_mark(struct fsnotify_mark *mark)
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+{
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+ struct fsnotify_group *group = mark->group;
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+
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+ WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex));
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+ WARN_ON_ONCE(!srcu_read_lock_held(&fsnotify_mark_srcu) &&
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+ atomic_read(&mark->refcnt) < 1 +
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+ !!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED));
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+
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+ spin_lock(&mark->lock);
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+ /* something else already called this function on this mark */
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+ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
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+ spin_unlock(&mark->lock);
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+ return;
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+ }
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+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
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+ list_del_init(&mark->g_list);
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+ spin_unlock(&mark->lock);
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atomic_dec(&group->num_marks);
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+
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+ /* Drop mark reference acquired in fsnotify_add_mark_locked() */
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+ fsnotify_put_mark(mark);
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}
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/*
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- * Prepare mark for freeing and add it to the list of marks prepared for
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- * freeing. The actual freeing must happen after SRCU period ends and the
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- * caller is responsible for this.
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+ * Free fsnotify mark. The mark is actually only marked as being freed. The
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+ * freeing is actually happening only once last reference to the mark is
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+ * dropped from a workqueue which first waits for srcu period end.
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*
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- * The function returns true if the mark was added to the list of marks for
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- * freeing. The function returns false if someone else has already called
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- * __fsnotify_free_mark() for the mark.
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+ * Caller must have a reference to the mark or be protected by
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+ * fsnotify_mark_srcu.
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*/
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-static bool __fsnotify_free_mark(struct fsnotify_mark *mark)
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+void fsnotify_free_mark(struct fsnotify_mark *mark)
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{
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struct fsnotify_group *group = mark->group;
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|
|
@@ -189,7 +373,7 @@ static bool __fsnotify_free_mark(struct fsnotify_mark *mark)
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/* something else already called this function on this mark */
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if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
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spin_unlock(&mark->lock);
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- return false;
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+ return;
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}
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mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
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spin_unlock(&mark->lock);
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@@ -201,25 +385,6 @@ static bool __fsnotify_free_mark(struct fsnotify_mark *mark)
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*/
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|
|
if (group->ops->freeing_mark)
|
|
|
group->ops->freeing_mark(mark, group);
|
|
|
-
|
|
|
- spin_lock(&destroy_lock);
|
|
|
- list_add(&mark->g_list, &destroy_list);
|
|
|
- spin_unlock(&destroy_lock);
|
|
|
-
|
|
|
- return true;
|
|
|
-}
|
|
|
-
|
|
|
-/*
|
|
|
- * Free fsnotify mark. The freeing is actually happening from a workqueue 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)
|
|
|
-{
|
|
|
- if (__fsnotify_free_mark(mark)) {
|
|
|
- queue_delayed_work(system_unbound_wq, &reaper_work,
|
|
|
- FSNOTIFY_REAPER_DELAY);
|
|
|
- }
|
|
|
}
|
|
|
|
|
|
void fsnotify_destroy_mark(struct fsnotify_mark *mark,
|
|
|
@@ -231,54 +396,6 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark,
|
|
|
fsnotify_free_mark(mark);
|
|
|
}
|
|
|
|
|
|
-void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock)
|
|
|
-{
|
|
|
- struct fsnotify_mark *mark;
|
|
|
-
|
|
|
- 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);
|
|
|
- }
|
|
|
-}
|
|
|
-
|
|
|
-void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask)
|
|
|
-{
|
|
|
- assert_spin_locked(&mark->lock);
|
|
|
-
|
|
|
- mark->mask = mask;
|
|
|
-
|
|
|
- if (mark->flags & FSNOTIFY_MARK_FLAG_INODE)
|
|
|
- fsnotify_set_inode_mark_mask_locked(mark, mask);
|
|
|
-}
|
|
|
-
|
|
|
-void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask)
|
|
|
-{
|
|
|
- assert_spin_locked(&mark->lock);
|
|
|
-
|
|
|
- mark->ignored_mask = mask;
|
|
|
-}
|
|
|
-
|
|
|
/*
|
|
|
* Sorting function for lists of fsnotify marks.
|
|
|
*
|
|
|
@@ -315,37 +432,133 @@ int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
|
|
|
return -1;
|
|
|
}
|
|
|
|
|
|
-/* Add mark into proper place in given list of marks */
|
|
|
-int fsnotify_add_mark_list(struct hlist_head *head, struct fsnotify_mark *mark,
|
|
|
- int allow_dups)
|
|
|
+static int fsnotify_attach_connector_to_object(
|
|
|
+ struct fsnotify_mark_connector __rcu **connp,
|
|
|
+ struct inode *inode,
|
|
|
+ struct vfsmount *mnt)
|
|
|
+{
|
|
|
+ struct fsnotify_mark_connector *conn;
|
|
|
+
|
|
|
+ conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_KERNEL);
|
|
|
+ if (!conn)
|
|
|
+ return -ENOMEM;
|
|
|
+ spin_lock_init(&conn->lock);
|
|
|
+ INIT_HLIST_HEAD(&conn->list);
|
|
|
+ if (inode) {
|
|
|
+ conn->flags = FSNOTIFY_OBJ_TYPE_INODE;
|
|
|
+ conn->inode = igrab(inode);
|
|
|
+ } else {
|
|
|
+ conn->flags = FSNOTIFY_OBJ_TYPE_VFSMOUNT;
|
|
|
+ conn->mnt = mnt;
|
|
|
+ }
|
|
|
+ /*
|
|
|
+ * cmpxchg() provides the barrier so that readers of *connp can see
|
|
|
+ * only initialized structure
|
|
|
+ */
|
|
|
+ if (cmpxchg(connp, NULL, conn)) {
|
|
|
+ /* Someone else created list structure for us */
|
|
|
+ if (inode)
|
|
|
+ iput(inode);
|
|
|
+ kmem_cache_free(fsnotify_mark_connector_cachep, conn);
|
|
|
+ }
|
|
|
+
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * Get mark connector, make sure it is alive and return with its lock held.
|
|
|
+ * This is for users that get connector pointer from inode or mount. Users that
|
|
|
+ * hold reference to a mark on the list may directly lock connector->lock as
|
|
|
+ * they are sure list cannot go away under them.
|
|
|
+ */
|
|
|
+static struct fsnotify_mark_connector *fsnotify_grab_connector(
|
|
|
+ struct fsnotify_mark_connector __rcu **connp)
|
|
|
+{
|
|
|
+ struct fsnotify_mark_connector *conn;
|
|
|
+ int idx;
|
|
|
+
|
|
|
+ idx = srcu_read_lock(&fsnotify_mark_srcu);
|
|
|
+ conn = srcu_dereference(*connp, &fsnotify_mark_srcu);
|
|
|
+ if (!conn)
|
|
|
+ goto out;
|
|
|
+ spin_lock(&conn->lock);
|
|
|
+ if (!(conn->flags & (FSNOTIFY_OBJ_TYPE_INODE |
|
|
|
+ FSNOTIFY_OBJ_TYPE_VFSMOUNT))) {
|
|
|
+ spin_unlock(&conn->lock);
|
|
|
+ srcu_read_unlock(&fsnotify_mark_srcu, idx);
|
|
|
+ return NULL;
|
|
|
+ }
|
|
|
+out:
|
|
|
+ srcu_read_unlock(&fsnotify_mark_srcu, idx);
|
|
|
+ return conn;
|
|
|
+}
|
|
|
+
|
|
|
+/*
|
|
|
+ * Add mark into proper place in given list of marks. These marks may be used
|
|
|
+ * for the fsnotify backend to determine which event types should be delivered
|
|
|
+ * to which group and for which inodes. These marks are ordered according to
|
|
|
+ * priority, highest number first, and then by the group's location in memory.
|
|
|
+ */
|
|
|
+static int fsnotify_add_mark_list(struct fsnotify_mark *mark,
|
|
|
+ struct inode *inode, struct vfsmount *mnt,
|
|
|
+ int allow_dups)
|
|
|
{
|
|
|
struct fsnotify_mark *lmark, *last = NULL;
|
|
|
+ struct fsnotify_mark_connector *conn;
|
|
|
+ struct fsnotify_mark_connector __rcu **connp;
|
|
|
int cmp;
|
|
|
+ int err = 0;
|
|
|
+
|
|
|
+ if (WARN_ON(!inode && !mnt))
|
|
|
+ return -EINVAL;
|
|
|
+ if (inode)
|
|
|
+ connp = &inode->i_fsnotify_marks;
|
|
|
+ else
|
|
|
+ connp = &real_mount(mnt)->mnt_fsnotify_marks;
|
|
|
+restart:
|
|
|
+ spin_lock(&mark->lock);
|
|
|
+ conn = fsnotify_grab_connector(connp);
|
|
|
+ if (!conn) {
|
|
|
+ spin_unlock(&mark->lock);
|
|
|
+ err = fsnotify_attach_connector_to_object(connp, inode, mnt);
|
|
|
+ if (err)
|
|
|
+ return err;
|
|
|
+ goto restart;
|
|
|
+ }
|
|
|
|
|
|
/* is mark the first mark? */
|
|
|
- if (hlist_empty(head)) {
|
|
|
- hlist_add_head_rcu(&mark->obj_list, head);
|
|
|
- return 0;
|
|
|
+ if (hlist_empty(&conn->list)) {
|
|
|
+ hlist_add_head_rcu(&mark->obj_list, &conn->list);
|
|
|
+ goto added;
|
|
|
}
|
|
|
|
|
|
/* should mark be in the middle of the current list? */
|
|
|
- hlist_for_each_entry(lmark, head, obj_list) {
|
|
|
+ hlist_for_each_entry(lmark, &conn->list, obj_list) {
|
|
|
last = lmark;
|
|
|
|
|
|
- if ((lmark->group == mark->group) && !allow_dups)
|
|
|
- return -EEXIST;
|
|
|
+ if ((lmark->group == mark->group) &&
|
|
|
+ (lmark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) &&
|
|
|
+ !allow_dups) {
|
|
|
+ err = -EEXIST;
|
|
|
+ goto out_err;
|
|
|
+ }
|
|
|
|
|
|
cmp = fsnotify_compare_groups(lmark->group, mark->group);
|
|
|
if (cmp >= 0) {
|
|
|
hlist_add_before_rcu(&mark->obj_list, &lmark->obj_list);
|
|
|
- return 0;
|
|
|
+ goto added;
|
|
|
}
|
|
|
}
|
|
|
|
|
|
BUG_ON(last == NULL);
|
|
|
/* mark should be the last entry. last is the current last entry */
|
|
|
hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
|
|
|
- return 0;
|
|
|
+added:
|
|
|
+ mark->connector = conn;
|
|
|
+out_err:
|
|
|
+ spin_unlock(&conn->lock);
|
|
|
+ spin_unlock(&mark->lock);
|
|
|
+ return err;
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
@@ -353,10 +566,10 @@ int fsnotify_add_mark_list(struct hlist_head *head, struct fsnotify_mark *mark,
|
|
|
* These marks may be used for the fsnotify backend to determine which
|
|
|
* event types should be delivered to which group.
|
|
|
*/
|
|
|
-int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
|
|
|
- struct fsnotify_group *group, struct inode *inode,
|
|
|
+int fsnotify_add_mark_locked(struct fsnotify_mark *mark, struct inode *inode,
|
|
|
struct vfsmount *mnt, int allow_dups)
|
|
|
{
|
|
|
+ struct fsnotify_group *group = mark->group;
|
|
|
int ret = 0;
|
|
|
|
|
|
BUG_ON(inode && mnt);
|
|
|
@@ -367,61 +580,42 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
|
|
|
* LOCKING ORDER!!!!
|
|
|
* group->mark_mutex
|
|
|
* mark->lock
|
|
|
- * inode->i_lock
|
|
|
+ * mark->connector->lock
|
|
|
*/
|
|
|
spin_lock(&mark->lock);
|
|
|
mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED;
|
|
|
|
|
|
- fsnotify_get_group(group);
|
|
|
- mark->group = group;
|
|
|
list_add(&mark->g_list, &group->marks_list);
|
|
|
atomic_inc(&group->num_marks);
|
|
|
- fsnotify_get_mark(mark); /* for i_list and g_list */
|
|
|
-
|
|
|
- if (inode) {
|
|
|
- ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups);
|
|
|
- if (ret)
|
|
|
- goto err;
|
|
|
- } else if (mnt) {
|
|
|
- ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups);
|
|
|
- if (ret)
|
|
|
- goto err;
|
|
|
- } else {
|
|
|
- BUG();
|
|
|
- }
|
|
|
-
|
|
|
- /* this will pin the object if appropriate */
|
|
|
- fsnotify_set_mark_mask_locked(mark, mark->mask);
|
|
|
+ fsnotify_get_mark(mark); /* for g_list */
|
|
|
spin_unlock(&mark->lock);
|
|
|
|
|
|
- if (inode)
|
|
|
- __fsnotify_update_child_dentry_flags(inode);
|
|
|
+ ret = fsnotify_add_mark_list(mark, inode, mnt, allow_dups);
|
|
|
+ if (ret)
|
|
|
+ goto err;
|
|
|
+
|
|
|
+ if (mark->mask)
|
|
|
+ fsnotify_recalc_mask(mark->connector);
|
|
|
|
|
|
return ret;
|
|
|
err:
|
|
|
- mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
|
|
|
+ mark->flags &= ~(FSNOTIFY_MARK_FLAG_ALIVE |
|
|
|
+ FSNOTIFY_MARK_FLAG_ATTACHED);
|
|
|
list_del_init(&mark->g_list);
|
|
|
- fsnotify_put_group(group);
|
|
|
- mark->group = NULL;
|
|
|
atomic_dec(&group->num_marks);
|
|
|
|
|
|
- spin_unlock(&mark->lock);
|
|
|
-
|
|
|
- spin_lock(&destroy_lock);
|
|
|
- list_add(&mark->g_list, &destroy_list);
|
|
|
- spin_unlock(&destroy_lock);
|
|
|
- queue_delayed_work(system_unbound_wq, &reaper_work,
|
|
|
- FSNOTIFY_REAPER_DELAY);
|
|
|
-
|
|
|
+ fsnotify_put_mark(mark);
|
|
|
return ret;
|
|
|
}
|
|
|
|
|
|
-int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group,
|
|
|
- struct inode *inode, struct vfsmount *mnt, int allow_dups)
|
|
|
+int fsnotify_add_mark(struct fsnotify_mark *mark, struct inode *inode,
|
|
|
+ struct vfsmount *mnt, int allow_dups)
|
|
|
{
|
|
|
int ret;
|
|
|
+ struct fsnotify_group *group = mark->group;
|
|
|
+
|
|
|
mutex_lock(&group->mark_mutex);
|
|
|
- ret = fsnotify_add_mark_locked(mark, group, inode, mnt, allow_dups);
|
|
|
+ ret = fsnotify_add_mark_locked(mark, inode, mnt, allow_dups);
|
|
|
mutex_unlock(&group->mark_mutex);
|
|
|
return ret;
|
|
|
}
|
|
|
@@ -430,29 +624,42 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group,
|
|
|
* Given a list of marks, find the mark associated with given group. If found
|
|
|
* take a reference to that mark and return it, else return NULL.
|
|
|
*/
|
|
|
-struct fsnotify_mark *fsnotify_find_mark(struct hlist_head *head,
|
|
|
- struct fsnotify_group *group)
|
|
|
+struct fsnotify_mark *fsnotify_find_mark(
|
|
|
+ struct fsnotify_mark_connector __rcu **connp,
|
|
|
+ struct fsnotify_group *group)
|
|
|
{
|
|
|
+ struct fsnotify_mark_connector *conn;
|
|
|
struct fsnotify_mark *mark;
|
|
|
|
|
|
- hlist_for_each_entry(mark, head, obj_list) {
|
|
|
- if (mark->group == group) {
|
|
|
+ conn = fsnotify_grab_connector(connp);
|
|
|
+ if (!conn)
|
|
|
+ return NULL;
|
|
|
+
|
|
|
+ hlist_for_each_entry(mark, &conn->list, obj_list) {
|
|
|
+ if (mark->group == group &&
|
|
|
+ (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
|
|
|
fsnotify_get_mark(mark);
|
|
|
+ spin_unlock(&conn->lock);
|
|
|
return mark;
|
|
|
}
|
|
|
}
|
|
|
+ spin_unlock(&conn->lock);
|
|
|
return NULL;
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * clear any marks in a group in which mark->flags & flags is true
|
|
|
- */
|
|
|
-void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group,
|
|
|
- unsigned int flags)
|
|
|
+/* Clear any marks in a group with given type */
|
|
|
+void fsnotify_clear_marks_by_group(struct fsnotify_group *group,
|
|
|
+ unsigned int type)
|
|
|
{
|
|
|
struct fsnotify_mark *lmark, *mark;
|
|
|
LIST_HEAD(to_free);
|
|
|
+ struct list_head *head = &to_free;
|
|
|
|
|
|
+ /* Skip selection step if we want to clear all marks. */
|
|
|
+ if (type == FSNOTIFY_OBJ_ALL_TYPES) {
|
|
|
+ head = &group->marks_list;
|
|
|
+ goto clear;
|
|
|
+ }
|
|
|
/*
|
|
|
* We have to be really careful here. Anytime we drop mark_mutex, e.g.
|
|
|
* fsnotify_clear_marks_by_inode() can come and free marks. Even in our
|
|
|
@@ -464,18 +671,19 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group,
|
|
|
*/
|
|
|
mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
|
|
|
list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) {
|
|
|
- if (mark->flags & flags)
|
|
|
+ if (mark->connector->flags & type)
|
|
|
list_move(&mark->g_list, &to_free);
|
|
|
}
|
|
|
mutex_unlock(&group->mark_mutex);
|
|
|
|
|
|
+clear:
|
|
|
while (1) {
|
|
|
mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
|
|
|
- if (list_empty(&to_free)) {
|
|
|
+ if (list_empty(head)) {
|
|
|
mutex_unlock(&group->mark_mutex);
|
|
|
break;
|
|
|
}
|
|
|
- mark = list_first_entry(&to_free, struct fsnotify_mark, g_list);
|
|
|
+ mark = list_first_entry(head, struct fsnotify_mark, g_list);
|
|
|
fsnotify_get_mark(mark);
|
|
|
fsnotify_detach_mark(mark);
|
|
|
mutex_unlock(&group->mark_mutex);
|
|
|
@@ -484,49 +692,62 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group,
|
|
|
}
|
|
|
}
|
|
|
|
|
|
-/*
|
|
|
- * Given a group, prepare for freeing all the marks associated with that group.
|
|
|
- * The marks are attached to the list of marks prepared for destruction, the
|
|
|
- * caller is responsible for freeing marks in that list after SRCU period has
|
|
|
- * ended.
|
|
|
- */
|
|
|
-void fsnotify_detach_group_marks(struct fsnotify_group *group)
|
|
|
+/* Destroy all marks attached to inode / vfsmount */
|
|
|
+void fsnotify_destroy_marks(struct fsnotify_mark_connector __rcu **connp)
|
|
|
{
|
|
|
- struct fsnotify_mark *mark;
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|
+ struct fsnotify_mark_connector *conn;
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|
|
+ struct fsnotify_mark *mark, *old_mark = NULL;
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|
|
+ struct inode *inode;
|
|
|
|
|
|
- while (1) {
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|
|
- mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING);
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|
|
- if (list_empty(&group->marks_list)) {
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|
|
- mutex_unlock(&group->mark_mutex);
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|
|
- break;
|
|
|
- }
|
|
|
- mark = list_first_entry(&group->marks_list,
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|
|
- struct fsnotify_mark, g_list);
|
|
|
+ conn = fsnotify_grab_connector(connp);
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|
|
+ if (!conn)
|
|
|
+ return;
|
|
|
+ /*
|
|
|
+ * We have to be careful since we can race with e.g.
|
|
|
+ * fsnotify_clear_marks_by_group() and once we drop the conn->lock, the
|
|
|
+ * list can get modified. However we are holding mark reference and
|
|
|
+ * thus our mark cannot be removed from obj_list so we can continue
|
|
|
+ * iteration after regaining conn->lock.
|
|
|
+ */
|
|
|
+ hlist_for_each_entry(mark, &conn->list, obj_list) {
|
|
|
fsnotify_get_mark(mark);
|
|
|
- fsnotify_detach_mark(mark);
|
|
|
- mutex_unlock(&group->mark_mutex);
|
|
|
- __fsnotify_free_mark(mark);
|
|
|
- fsnotify_put_mark(mark);
|
|
|
+ spin_unlock(&conn->lock);
|
|
|
+ if (old_mark)
|
|
|
+ fsnotify_put_mark(old_mark);
|
|
|
+ old_mark = mark;
|
|
|
+ fsnotify_destroy_mark(mark, mark->group);
|
|
|
+ spin_lock(&conn->lock);
|
|
|
}
|
|
|
+ /*
|
|
|
+ * Detach list from object now so that we don't pin inode until all
|
|
|
+ * mark references get dropped. It would lead to strange results such
|
|
|
+ * as delaying inode deletion or blocking unmount.
|
|
|
+ */
|
|
|
+ inode = fsnotify_detach_connector_from_object(conn);
|
|
|
+ spin_unlock(&conn->lock);
|
|
|
+ if (old_mark)
|
|
|
+ fsnotify_put_mark(old_mark);
|
|
|
+ iput(inode);
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
* Nothing fancy, just initialize lists and locks and counters.
|
|
|
*/
|
|
|
void fsnotify_init_mark(struct fsnotify_mark *mark,
|
|
|
- void (*free_mark)(struct fsnotify_mark *mark))
|
|
|
+ struct fsnotify_group *group)
|
|
|
{
|
|
|
memset(mark, 0, sizeof(*mark));
|
|
|
spin_lock_init(&mark->lock);
|
|
|
atomic_set(&mark->refcnt, 1);
|
|
|
- mark->free_mark = free_mark;
|
|
|
+ fsnotify_get_group(group);
|
|
|
+ mark->group = group;
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
* Destroy all marks in destroy_list, waits for SRCU period to finish before
|
|
|
* actually freeing marks.
|
|
|
*/
|
|
|
-void fsnotify_mark_destroy_list(void)
|
|
|
+static void fsnotify_mark_destroy_workfn(struct work_struct *work)
|
|
|
{
|
|
|
struct fsnotify_mark *mark, *next;
|
|
|
struct list_head private_destroy_list;
|
|
|
@@ -540,11 +761,12 @@ void fsnotify_mark_destroy_list(void)
|
|
|
|
|
|
list_for_each_entry_safe(mark, next, &private_destroy_list, g_list) {
|
|
|
list_del_init(&mark->g_list);
|
|
|
- fsnotify_put_mark(mark);
|
|
|
+ fsnotify_final_mark_destroy(mark);
|
|
|
}
|
|
|
}
|
|
|
|
|
|
-static void fsnotify_mark_destroy_workfn(struct work_struct *work)
|
|
|
+/* Wait for all marks queued for destruction to be actually destroyed */
|
|
|
+void fsnotify_wait_marks_destroyed(void)
|
|
|
{
|
|
|
- fsnotify_mark_destroy_list();
|
|
|
+ flush_delayed_work(&reaper_work);
|
|
|
}
|
Linus Torvalds