FS-Cache: Don't delete pending pages from the page-store tracking tree

Don't delete pending pages from the page-store tracking tree, but rather send
them for another write as they've presumably been updated.

Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 3ea8897..022a5da 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -57,8 +57,11 @@
 		/* delete the page from the tree if it is now no longer
 		 * pending */
 		spin_lock(&cookie->stores_lock);
-		fscache_stat(&fscache_n_store_radix_deletes);
-		xpage = radix_tree_delete(&cookie->stores, page->index);
+		if (!radix_tree_tag_get(&cookie->stores, page->index,
+					FSCACHE_COOKIE_PENDING_TAG)) {
+			fscache_stat(&fscache_n_store_radix_deletes);
+			xpage = radix_tree_delete(&cookie->stores, page->index);
+		}
 		spin_unlock(&cookie->stores_lock);
 		wake_up_bit(&cookie->flags, 0);
 	}