[PATCH] mutex subsystem, semaphore to mutex: VFS, sb->s_lock

This patch converts the superblock-lock semaphore to a mutex, affecting
lock_super()/unlock_super(). Tested on ext3 and XFS.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 48bf7f0..364d64b 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -169,7 +169,7 @@
  */
 static void ocfs2_write_super(struct super_block *sb)
 {
-	if (down_trylock(&sb->s_lock) == 0)
+	if (mutex_trylock(&sb->s_lock) != 0)
 		BUG();
 	sb->s_dirt = 0;
 }