*
* group->mark_mutex
* mark->lock
- * inode->i_lock
+ * mark->connector->lock
*
* group->mark_mutex protects the marks_list anchored inside a given group and
* each mark is hooked via the g_list. It also protects the groups private
* is assigned to as well as the access to a reference of the inode/vfsmount
* that is being watched by the mark.
*
- * inode->i_lock protects the i_fsnotify_marks list anchored inside a
- * given inode and each mark is hooked via the i_list. (and sorta the
- * free_i_list)
+ * mark->connector->lock protects the list of marks anchored inside an
+ * inode / vfsmount and each mark is hooked via the i_list.
*
+ * A list of notification marks relating to inode / mnt is contained in
+ * fsnotify_mark_connector. That structure is alive as long as there are any
+ * marks in the list and is also protected by fsnotify_mark_srcu. A mark gets
+ * detached from fsnotify_mark_connector when last reference to the mark is
+ * dropped. Thus having mark reference is enough to protect mark->connector
+ * pointer and to make sure fsnotify_mark_connector cannot disappear. Also
+ * because we remove mark from g_list before dropping mark reference associated
+ * with that, any mark found through g_list is guaranteed to have
+ * mark->connector set until we drop group->mark_mutex.
*
* LIFETIME:
* Inode marks survive between when they are added to an inode and when their
- * refcnt==0.
+ * refcnt==0. Marks are also protected by fsnotify_mark_srcu.
*
* The inode mark can be cleared for a number of different reasons including:
* - The inode is unlinked for the last time. (fsnotify_inode_remove)
* - The fsnotify_group associated with the mark is going away and all such marks
* need to be cleaned up. (fsnotify_clear_marks_by_group)
*
- * Worst case we are given an inode and need to clean up all the marks on that
- * inode. We take i_lock and walk the i_fsnotify_marks safely. For each
- * mark on the list we take a reference (so the mark can't disappear under us).
- * We remove that mark form the inode's list of marks and we add this mark to a
- * private list anchored on the stack using i_free_list; we walk i_free_list
- * and before we destroy the mark we make sure that we dont race with a
- * concurrent destroy_group by getting a ref to the marks group and taking the
- * groups mutex.
-
- * Very similarly for freeing by group, except we use free_g_list.
- *
* This has the very interesting property of being able to run concurrently with
* any (or all) other directions.
*/
#define FSNOTIFY_REAPER_DELAY (1) /* 1 jiffy */
struct srcu_struct fsnotify_mark_srcu;
+struct kmem_cache *fsnotify_mark_connector_cachep;
+
static DEFINE_SPINLOCK(destroy_lock);
static LIST_HEAD(destroy_list);
+static struct fsnotify_mark_connector *connector_destroy_list;
static void fsnotify_mark_destroy_workfn(struct work_struct *work);
static DECLARE_DELAYED_WORK(reaper_work, fsnotify_mark_destroy_workfn);
+static void fsnotify_connector_destroy_workfn(struct work_struct *work);
+static DECLARE_WORK(connector_reaper_work, fsnotify_connector_destroy_workfn);
+
void fsnotify_get_mark(struct fsnotify_mark *mark)
{
+ WARN_ON_ONCE(!atomic_read(&mark->refcnt));
atomic_inc(&mark->refcnt);
}
-void fsnotify_put_mark(struct fsnotify_mark *mark)
+/*
+ * Get mark reference when we found the mark via lockless traversal of object
+ * list. Mark can be already removed from the list by now and on its way to be
+ * destroyed once SRCU period ends.
+ */
+static bool fsnotify_get_mark_safe(struct fsnotify_mark *mark)
{
- if (atomic_dec_and_test(&mark->refcnt)) {
- if (mark->group)
- fsnotify_put_group(mark->group);
- mark->free_mark(mark);
- }
+ return atomic_inc_not_zero(&mark->refcnt);
}
-/* Calculate mask of events for a list of marks */
-u32 fsnotify_recalc_mask(struct hlist_head *head)
+static void __fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
{
u32 new_mask = 0;
struct fsnotify_mark *mark;
- hlist_for_each_entry(mark, head, obj_list)
- new_mask |= mark->mask;
- return new_mask;
+ assert_spin_locked(&conn->lock);
+ hlist_for_each_entry(mark, &conn->list, obj_list) {
+ if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)
+ new_mask |= mark->mask;
+ }
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+ conn->inode->i_fsnotify_mask = new_mask;
+ else if (conn->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT)
+ real_mount(conn->mnt)->mnt_fsnotify_mask = new_mask;
}
/*
- * Remove mark from inode / vfsmount list, group list, drop inode reference
- * if we got one.
- *
- * Must be called with group->mark_mutex held.
+ * Calculate mask of events for a list of marks. The caller must make sure
+ * connector and connector->inode cannot disappear under us. Callers achieve
+ * this by holding a mark->lock or mark->group->mark_mutex for a mark on this
+ * list.
*/
-void fsnotify_detach_mark(struct fsnotify_mark *mark)
+void fsnotify_recalc_mask(struct fsnotify_mark_connector *conn)
+{
+ if (!conn)
+ return;
+
+ spin_lock(&conn->lock);
+ __fsnotify_recalc_mask(conn);
+ spin_unlock(&conn->lock);
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE)
+ __fsnotify_update_child_dentry_flags(conn->inode);
+}
+
+/* Free all connectors queued for freeing once SRCU period ends */
+static void fsnotify_connector_destroy_workfn(struct work_struct *work)
+{
+ struct fsnotify_mark_connector *conn, *free;
+
+ spin_lock(&destroy_lock);
+ conn = connector_destroy_list;
+ connector_destroy_list = NULL;
+ spin_unlock(&destroy_lock);
+
+ synchronize_srcu(&fsnotify_mark_srcu);
+ while (conn) {
+ free = conn;
+ conn = conn->destroy_next;
+ kmem_cache_free(fsnotify_mark_connector_cachep, free);
+ }
+}
+
+static struct inode *fsnotify_detach_connector_from_object(
+ struct fsnotify_mark_connector *conn)
{
struct inode *inode = NULL;
- struct fsnotify_group *group = mark->group;
- BUG_ON(!mutex_is_locked(&group->mark_mutex));
+ if (conn->flags & FSNOTIFY_OBJ_TYPE_INODE) {
+ inode = conn->inode;
+ rcu_assign_pointer(inode->i_fsnotify_marks, NULL);
+ inode->i_fsnotify_mask = 0;
+ conn->inode = NULL;
+ conn->flags &= ~FSNOTIFY_OBJ_TYPE_INODE;
+ } else if (conn->flags & FSNOTIFY_OBJ_TYPE_VFSMOUNT) {
+ rcu_assign_pointer(real_mount(conn->mnt)->mnt_fsnotify_marks,
+ NULL);
+ real_mount(conn->mnt)->mnt_fsnotify_mask = 0;
+ conn->mnt = NULL;
+ conn->flags &= ~FSNOTIFY_OBJ_TYPE_VFSMOUNT;
+ }
- spin_lock(&mark->lock);
+ return inode;
+}
- /* something else already called this function on this mark */
- if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
- spin_unlock(&mark->lock);
+static void fsnotify_final_mark_destroy(struct fsnotify_mark *mark)
+{
+ if (mark->group)
+ fsnotify_put_group(mark->group);
+ mark->free_mark(mark);
+}
+
+void fsnotify_put_mark(struct fsnotify_mark *mark)
+{
+ struct fsnotify_mark_connector *conn;
+ struct inode *inode = NULL;
+ bool free_conn = false;
+
+ /* Catch marks that were actually never attached to object */
+ if (!mark->connector) {
+ if (atomic_dec_and_test(&mark->refcnt))
+ fsnotify_final_mark_destroy(mark);
return;
}
- mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
+ /*
+ * We have to be careful so that traversals of obj_list under lock can
+ * safely grab mark reference.
+ */
+ if (!atomic_dec_and_lock(&mark->refcnt, &mark->connector->lock))
+ return;
- if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) {
- inode = mark->inode;
- fsnotify_destroy_inode_mark(mark);
- } else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT)
- fsnotify_destroy_vfsmount_mark(mark);
- else
- BUG();
+ conn = mark->connector;
+ hlist_del_init_rcu(&mark->obj_list);
+ if (hlist_empty(&conn->list)) {
+ inode = fsnotify_detach_connector_from_object(conn);
+ free_conn = true;
+ } else {
+ __fsnotify_recalc_mask(conn);
+ }
+ mark->connector = NULL;
+ spin_unlock(&conn->lock);
+
+ iput(inode);
+
+ if (free_conn) {
+ spin_lock(&destroy_lock);
+ conn->destroy_next = connector_destroy_list;
+ connector_destroy_list = conn;
+ spin_unlock(&destroy_lock);
+ queue_work(system_unbound_wq, &connector_reaper_work);
+ }
/*
* 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.
*/
+ 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);
+}
- list_del_init(&mark->g_list);
+bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info)
+{
+ struct fsnotify_group *group;
- spin_unlock(&mark->lock);
+ if (WARN_ON_ONCE(!iter_info->inode_mark && !iter_info->vfsmount_mark))
+ return false;
+
+ if (iter_info->inode_mark)
+ group = iter_info->inode_mark->group;
+ else
+ group = iter_info->vfsmount_mark->group;
+
+ /*
+ * Since acquisition of mark reference is an atomic op as well, we can
+ * be sure this inc is seen before any effect of refcount increment.
+ */
+ atomic_inc(&group->user_waits);
+
+ if (iter_info->inode_mark) {
+ /* This can fail if mark is being removed */
+ if (!fsnotify_get_mark_safe(iter_info->inode_mark))
+ goto out_wait;
+ }
+ if (iter_info->vfsmount_mark) {
+ if (!fsnotify_get_mark_safe(iter_info->vfsmount_mark))
+ goto out_inode;
+ }
+
+ /*
+ * Now that both marks are pinned by refcount in the inode / vfsmount
+ * lists, we can drop SRCU lock, and safely resume the list iteration
+ * once userspace returns.
+ */
+ srcu_read_unlock(&fsnotify_mark_srcu, iter_info->srcu_idx);
+
+ return true;
+out_inode:
+ if (iter_info->inode_mark)
+ fsnotify_put_mark(iter_info->inode_mark);
+out_wait:
+ if (atomic_dec_and_test(&group->user_waits) && group->shutdown)
+ wake_up(&group->notification_waitq);
+ return false;
+}
- if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED))
- iput(inode);
+void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info)
+{
+ struct fsnotify_group *group = NULL;
+
+ iter_info->srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
+ if (iter_info->inode_mark) {
+ group = iter_info->inode_mark->group;
+ fsnotify_put_mark(iter_info->inode_mark);
+ }
+ if (iter_info->vfsmount_mark) {
+ group = iter_info->vfsmount_mark->group;
+ fsnotify_put_mark(iter_info->vfsmount_mark);
+ }
+ /*
+ * We abuse notification_waitq on group shutdown for waiting for all
+ * marks pinned when waiting for userspace.
+ */
+ if (atomic_dec_and_test(&group->user_waits) && group->shutdown)
+ wake_up(&group->notification_waitq);
+}
+
+/*
+ * Mark mark as detached, remove it from group list. Mark still stays in object
+ * list until its last reference is dropped. Note that we rely on mark being
+ * removed from group list before corresponding reference to it is dropped. In
+ * particular we rely on mark->connector being valid while we hold
+ * group->mark_mutex if we found the mark through g_list.
+ *
+ * Must be called with group->mark_mutex held. The caller must either hold
+ * reference to the mark or be protected by fsnotify_mark_srcu.
+ */
+void fsnotify_detach_mark(struct fsnotify_mark *mark)
+{
+ struct fsnotify_group *group = mark->group;
+
+ WARN_ON_ONCE(!mutex_is_locked(&group->mark_mutex));
+ WARN_ON_ONCE(!srcu_read_lock_held(&fsnotify_mark_srcu) &&
+ atomic_read(&mark->refcnt) < 1 +
+ !!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED));
+
+ spin_lock(&mark->lock);
+ /* something else already called this function on this mark */
+ if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) {
+ spin_unlock(&mark->lock);
+ return;
+ }
+ mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED;
+ list_del_init(&mark->g_list);
+ spin_unlock(&mark->lock);
atomic_dec(&group->num_marks);
+
+ /* Drop mark reference acquired in fsnotify_add_mark_locked() */
+ fsnotify_put_mark(mark);
}
/*
- * Prepare mark for freeing and add it to the list of marks prepared for
- * freeing. The actual freeing must happen after SRCU period ends and the
- * caller is responsible for this.
+ * Free fsnotify mark. The mark is actually only marked as being freed. The
+ * freeing is actually happening only once last reference to the mark is
+ * dropped from a workqueue which first waits for srcu period end.
*
- * The function returns true if the mark was added to the list of marks for
- * freeing. The function returns false if someone else has already called
- * __fsnotify_free_mark() for the mark.
+ * Caller must have a reference to the mark or be protected by
+ * fsnotify_mark_srcu.
*/
-static bool __fsnotify_free_mark(struct fsnotify_mark *mark)
+void fsnotify_free_mark(struct fsnotify_mark *mark)
{
struct fsnotify_group *group = mark->group;
/* something else already called this function on this mark */
if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) {
spin_unlock(&mark->lock);
- return false;
+ return;
}
mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE;
spin_unlock(&mark->lock);
*/
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,
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)
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;
}
/*
* 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;
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;
}
* 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;
}
*/
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 & flags)
list_move(&mark->g_list, &to_free);
}
mutex_unlock(&group->mark_mutex);
fsnotify_get_mark(mark);
fsnotify_detach_mark(mark);
mutex_unlock(&group->mark_mutex);
- __fsnotify_free_mark(mark);
+ fsnotify_free_mark(mark);
fsnotify_put_mark(mark);
}
+ /*
+ * Some marks can still be pinned when waiting for response from
+ * userspace. Wait for those now. fsnotify_prepare_user_wait() will
+ * not succeed now so this wait is race-free.
+ */
+ wait_event(group->notification_waitq, !atomic_read(&group->user_waits));
+}
+
+/* Destroy all marks attached to inode / vfsmount */
+void fsnotify_destroy_marks(struct fsnotify_mark_connector __rcu **connp)
+{
+ struct fsnotify_mark_connector *conn;
+ struct fsnotify_mark *mark, *old_mark = NULL;
+ struct inode *inode;
+
+ conn = fsnotify_grab_connector(connp);
+ 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);
+ 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);
}
/*
* 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;
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);
}
git.samba.org / sfrench / cifs-2.6.git / blobdiff