[PATCH] fix invalidate_inode_pages2_range not to clear ret

[Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>]

Hi.

DIO invalidates page cache through invalidate_inode_pages2_range().
invalidate_inode_pages2_range() sets ret=-EIO when invalidate_complete_page2()
fails, but this ret is cleared if do_launder_page() succeed on a page of 
next index.
In this case, dio is carried out even if invalidate_complete_page2() fails 
on some pages.
This can cause inconsistency between memory and blocks on HDD because the page
cache still exists.

Following patch fixes this issue.

Thanks.

Signed-off-by :Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>

diff -Nrup linux-2.6.24-rc5.org/mm/truncate.c linux-2.6.24-rc5/mm/truncate.c
--- linux-2.6.24-rc5.org/mm/truncate.c	2007-12-12 16:32:45.000000000 +0900
+++ linux-2.6.24-rc5/mm/truncate.c	2007-12-13 11:45:29.000000000 +0900
@@ -392,6 +392,7 @@ int invalidate_inode_pages2_range(struct
  	pgoff_t next;
  	int i;
  	int ret = 0;
+	int ret2 = 0;
  	int did_range_unmap = 0;
  	int wrapped = 0;

@@ -441,13 +442,13 @@ int invalidate_inode_pages2_range(struct
  			BUG_ON(page_mapped(page));
  			ret = do_launder_page(mapping, page);
  			if (ret == 0 && !invalidate_complete_page2(mapping, page))
-				ret = -EIO;
+				ret2 = -EIO;
  			unlock_page(page);
  		}
  		pagevec_release(&pvec);
  		cond_resched();
  	}
-	return ret;
+	return !ret ? ret2 : ret;
  }
  EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);