FS-Cache: Put an aborted initialised op so that it is accounted correctly

Call fscache_put_operation() or a wrapper on any op that has gone through
fscache_operation_init() so that the accounting shown in /proc is done
correctly, specifically fscache_n_op_release.

fscache_put_operation() therefore now allows an op in the INITIALISED state as
well as in the CANCELLED and COMPLETE states.

Note that this means that an operation can get put that doesn't have its
->object pointer filled in, so anything that depends on the object needs to be
conditional in fscache_put_operation().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Steve Dickson <steved@redhat.com>
Acked-by: Jeff Layton <jeff.layton@primarydata.com>

2 files changed, 35 insertions, 33 deletions

diff --git a/fs/fscache/operation.c b/fs/fscache/operation.c
index b6bf5f3..c76c097 100644
--- a/fs/fscache/operation.c
+++ b/fs/fscache/operation.c
@@ -472,7 +472,8 @@ void fscache_put_operation(struct fscache_operation *op)
 		return;
 
 	_debug("PUT OP");
-	ASSERTIFCMP(op->state != FSCACHE_OP_ST_COMPLETE,
+	ASSERTIFCMP(op->state != FSCACHE_OP_ST_INITIALISED &&
+		    op->state != FSCACHE_OP_ST_COMPLETE,
 		    op->state, ==, FSCACHE_OP_ST_CANCELLED);
 	op->state = FSCACHE_OP_ST_DEAD;
 
@@ -484,35 +485,36 @@ void fscache_put_operation(struct fscache_operation *op)
 	}
 
 	object = op->object;
+	if (likely(object)) {
+		if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
+			atomic_dec(&object->n_reads);
+		if (test_bit(FSCACHE_OP_UNUSE_COOKIE, &op->flags))
+			fscache_unuse_cookie(object);
+
+		/* now... we may get called with the object spinlock held, so we
+		 * complete the cleanup here only if we can immediately acquire the
+		 * lock, and defer it otherwise */
+		if (!spin_trylock(&object->lock)) {
+			_debug("defer put");
+			fscache_stat(&fscache_n_op_deferred_release);
+
+			cache = object->cache;
+			spin_lock(&cache->op_gc_list_lock);
+			list_add_tail(&op->pend_link, &cache->op_gc_list);
+			spin_unlock(&cache->op_gc_list_lock);
+			schedule_work(&cache->op_gc);
+			_leave(" [defer]");
+			return;
+		}
 
-	if (test_bit(FSCACHE_OP_DEC_READ_CNT, &op->flags))
-		atomic_dec(&object->n_reads);
-	if (test_bit(FSCACHE_OP_UNUSE_COOKIE, &op->flags))
-		fscache_unuse_cookie(object);
-
-	/* now... we may get called with the object spinlock held, so we
-	 * complete the cleanup here only if we can immediately acquire the
-	 * lock, and defer it otherwise */
-	if (!spin_trylock(&object->lock)) {
-		_debug("defer put");
-		fscache_stat(&fscache_n_op_deferred_release);
+		ASSERTCMP(object->n_ops, >, 0);
+		object->n_ops--;
+		if (object->n_ops == 0)
+			fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
 
-		cache = object->cache;
-		spin_lock(&cache->op_gc_list_lock);
-		list_add_tail(&op->pend_link, &cache->op_gc_list);
-		spin_unlock(&cache->op_gc_list_lock);
-		schedule_work(&cache->op_gc);
-		_leave(" [defer]");
-		return;
+		spin_unlock(&object->lock);
 	}
 
-	ASSERTCMP(object->n_ops, >, 0);
-	object->n_ops--;
-	if (object->n_ops == 0)
-		fscache_raise_event(object, FSCACHE_OBJECT_EV_CLEARED);
-
-	spin_unlock(&object->lock);
-
 	kfree(op);
 	_leave(" [done]");
 }
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 433cae9..7db9752 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -239,7 +239,7 @@ nobufs_dec:
 	wake_cookie = __fscache_unuse_cookie(cookie);
 nobufs:
 	spin_unlock(&cookie->lock);
-	kfree(op);
+	fscache_put_operation(op);
 	if (wake_cookie)
 		__fscache_wake_unused_cookie(cookie);
 	fscache_stat(&fscache_n_attr_changed_nobufs);
@@ -505,7 +505,7 @@ nobufs_unlock:
 	spin_unlock(&cookie->lock);
 	if (wake_cookie)
 		__fscache_wake_unused_cookie(cookie);
-	kfree(op);
+	fscache_put_retrieval(op);
 nobufs:
 	fscache_stat(&fscache_n_retrievals_nobufs);
 	_leave(" = -ENOBUFS");
@@ -634,7 +634,7 @@ nobufs_unlock_dec:
 	wake_cookie = __fscache_unuse_cookie(cookie);
 nobufs_unlock:
 	spin_unlock(&cookie->lock);
-	kfree(op);
+	fscache_put_retrieval(op);
 	if (wake_cookie)
 		__fscache_wake_unused_cookie(cookie);
 nobufs:
@@ -728,7 +728,7 @@ nobufs_unlock_dec:
 	wake_cookie = __fscache_unuse_cookie(cookie);
 nobufs_unlock:
 	spin_unlock(&cookie->lock);
-	kfree(op);
+	fscache_put_retrieval(op);
 	if (wake_cookie)
 		__fscache_wake_unused_cookie(cookie);
 nobufs:
@@ -1018,7 +1018,7 @@ already_pending:
 	spin_unlock(&object->lock);
 	spin_unlock(&cookie->lock);
 	radix_tree_preload_end();
-	kfree(op);
+	fscache_put_operation(&op->op);
 	fscache_stat(&fscache_n_stores_ok);
 	_leave(" = 0");
 	return 0;
@@ -1038,7 +1038,7 @@ nobufs_unlock_obj:
 nobufs:
 	spin_unlock(&cookie->lock);
 	radix_tree_preload_end();
-	kfree(op);
+	fscache_put_operation(&op->op);
 	if (wake_cookie)
 		__fscache_wake_unused_cookie(cookie);
 	fscache_stat(&fscache_n_stores_nobufs);
@@ -1046,7 +1046,7 @@ nobufs:
 	return -ENOBUFS;
 
 nomem_free:
-	kfree(op);
+	fscache_put_operation(&op->op);
 nomem:
 	fscache_stat(&fscache_n_stores_oom);
 	_leave(" = -ENOMEM");