f2fs: Update to proper 3.4 support

http://git.kernel.org/cgit/linux/kernel/git/jaegeuk/f2fs.git/log/?h=linux-3.4

Change-Id: Ica17871e847d4807c7ef24ea77dd4bff5451f5c7

Conflicts:
	fs/f2fs/f2fs.h
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 115de74..47c51ed 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -45,6 +45,11 @@
 		if (kthread_should_stop())
 			break;
 
+		if (sbi->sb->s_frozen >= SB_FREEZE_WRITE) {
+			wait_ms = increase_sleep_time(gc_th, wait_ms);
+			continue;
+		}
+
 		/*
 		 * [GC triggering condition]
 		 * 0. GC is not conducted currently.
@@ -246,7 +251,7 @@
 }
 
 /*
- * This function is called from two pathes.
+ * This function is called from two paths.
  * One is garbage collection and the other is SSR segment selection.
  * When it is called during GC, it just gets a victim segment
  * and it does not remove it from dirty seglist.