fs: fix buffer invalidation in invalidate_list

We must not call invalidate_inode_buffers in invalidate_list unless the
inode can be reclaimed.  If we remove the buffer association of a busy
inode fsync won't find the buffers anymore.  As invalidate_inode_buffers
is called from various others sources than umount this actually does
matter in practice.

While at it change the loop to a more natural form and remove the
WARN_ON for I_NEW, wich we already tested a few lines above.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/inode.c

@@ -28,7 +28,6 @@
 /*
  * This is needed for the following functions:
  *  - inode_has_buffers
- *  - invalidate_inode_buffers
  *  - invalidate_bdev
  *
  * FIXME: remove all knowledge of the buffer layer from this file
@@ -503,16 +502,15 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
 		inode = list_entry(tmp, struct inode, i_sb_list);
 		if (inode->i_state & I_NEW)
 			continue;
-		invalidate_inode_buffers(inode);
-		if (!atomic_read(&inode->i_count)) {
+		if (atomic_read(&inode->i_count)) {
+			busy = 1;
+			continue;
+		}
+
 		list_move(&inode->i_list, dispose);
-			WARN_ON(inode->i_state & I_NEW);
 		inode->i_state |= I_FREEING;
 		if (!(inode->i_state & (I_DIRTY | I_SYNC)))
 			percpu_counter_dec(&nr_inodes_unused);
-			continue;
-		}
-		busy = 1;
 	}
 	return busy;
 }