Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull fscache fixes from Al Viro.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fscache: Fix dead object requeue
  fscache: Clear outstanding writes when disabling a cookie
  FS-Cache: Initialise stores_lock in netfs cookie

4 files changed, 37 insertions, 2 deletions

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 4304072161aa..40d61077bead 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -542,6 +542,7 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate)
 		hlist_for_each_entry(object, &cookie->backing_objects, cookie_link) {
 			if (invalidate)
 				set_bit(FSCACHE_OBJECT_RETIRED, &object->flags);
+			clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
 			fscache_raise_event(object, FSCACHE_OBJECT_EV_KILL);
 		}
 	} else {
@@ -560,6 +561,10 @@ void __fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate)
 		wait_on_atomic_t(&cookie->n_active, fscache_wait_atomic_t,
 				 TASK_UNINTERRUPTIBLE);
 
+	/* Make sure any pending writes are cancelled. */
+	if (cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
+		fscache_invalidate_writes(cookie);
+
 	/* Reset the cookie state if it wasn't relinquished */
 	if (!test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags)) {
 		atomic_inc(&cookie->n_active);
diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 9b28649df3a1..a8aa00be4444 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -48,6 +48,7 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
 	cookie->flags		= 1 << FSCACHE_COOKIE_ENABLED;
 
 	spin_lock_init(&cookie->lock);
+	spin_lock_init(&cookie->stores_lock);
 	INIT_HLIST_HEAD(&cookie->backing_objects);
 
 	/* check the netfs type is not already present */
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 9e792e30f4db..7a182c87f378 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -30,6 +30,7 @@ static const struct fscache_state *fscache_look_up_object(struct fscache_object
 static const struct fscache_state *fscache_object_available(struct fscache_object *, int);
 static const struct fscache_state *fscache_parent_ready(struct fscache_object *, int);
 static const struct fscache_state *fscache_update_object(struct fscache_object *, int);
+static const struct fscache_state *fscache_object_dead(struct fscache_object *, int);
 
 #define __STATE_NAME(n) fscache_osm_##n
 #define STATE(n) (&__STATE_NAME(n))
@@ -91,7 +92,7 @@ static WORK_STATE(LOOKUP_FAILURE,	"LCFL", fscache_lookup_failure);
 static WORK_STATE(KILL_OBJECT,		"KILL", fscache_kill_object);
 static WORK_STATE(KILL_DEPENDENTS,	"KDEP", fscache_kill_dependents);
 static WORK_STATE(DROP_OBJECT,		"DROP", fscache_drop_object);
-static WORK_STATE(OBJECT_DEAD,		"DEAD", (void*)2UL);
+static WORK_STATE(OBJECT_DEAD,		"DEAD", fscache_object_dead);
 
 static WAIT_STATE(WAIT_FOR_INIT,	"?INI",
 		  TRANSIT_TO(INIT_OBJECT,	1 << FSCACHE_OBJECT_EV_NEW_CHILD));
@@ -229,6 +230,10 @@ execute_work_state:
 	event = -1;
 	if (new_state == NO_TRANSIT) {
 		_debug("{OBJ%x} %s notrans", object->debug_id, state->name);
+		if (unlikely(state == STATE(OBJECT_DEAD))) {
+			_leave(" [dead]");
+			return;
+		}
 		fscache_enqueue_object(object);
 		event_mask = object->oob_event_mask;
 		goto unmask_events;
@@ -239,7 +244,7 @@ execute_work_state:
 	object->state = state = new_state;
 
 	if (state->work) {
-		if (unlikely(state->work == ((void *)2UL))) {
+		if (unlikely(state == STATE(OBJECT_DEAD))) {
 			_leave(" [dead]");
 			return;
 		}
@@ -645,6 +650,12 @@ static const struct fscache_state *fscache_kill_object(struct fscache_object *ob
 	fscache_mark_object_dead(object);
 	object->oob_event_mask = 0;
 
+	if (test_bit(FSCACHE_OBJECT_RETIRED, &object->flags)) {
+		/* Reject any new read/write ops and abort any that are pending. */
+		clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
+		fscache_cancel_all_ops(object);
+	}
+
 	if (list_empty(&object->dependents) &&
 	    object->n_ops == 0 &&
 	    object->n_children == 0)
@@ -1077,3 +1088,20 @@ void fscache_object_mark_killed(struct fscache_object *object,
 	}
 }
 EXPORT_SYMBOL(fscache_object_mark_killed);
+
+/*
+ * The object is dead.  We can get here if an object gets queued by an event
+ * that would lead to its death (such as EV_KILL) when the dispatcher is
+ * already running (and so can be requeued) but hasn't yet cleared the event
+ * mask.
+ */
+static const struct fscache_state *fscache_object_dead(struct fscache_object *object,
+						       int event)
+{
+	if (!test_and_set_bit(FSCACHE_OBJECT_RUN_AFTER_DEAD,
+			      &object->flags))
+		return NO_TRANSIT;
+
+	WARN(true, "FS-Cache object redispatched after death");
+	return NO_TRANSIT;
+}
diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h
index 13ba552e6c09..4c467ef50159 100644
--- a/include/linux/fscache-cache.h
+++ b/include/linux/fscache-cache.h
@@ -360,6 +360,7 @@ struct fscache_object {
 #define FSCACHE_OBJECT_IS_AVAILABLE	5	/* T if object has become active */
 #define FSCACHE_OBJECT_RETIRED		6	/* T if object was retired on relinquishment */
 #define FSCACHE_OBJECT_KILLED_BY_CACHE	7	/* T if object was killed by the cache */
+#define FSCACHE_OBJECT_RUN_AFTER_DEAD	8	/* T if object has been dispatched after death */
 
 	struct list_head	cache_link;	/* link in cache->object_list */
 	struct hlist_node	cookie_link;	/* link in cookie->backing_objects */