GIT: unionfs2-2.6.27.y: Unionfs: cast page->index loff_t before shifting

[Erez Zadok]

commit a3047a7e930398e5b0199dff6096f933886cc3b2
Author: Erez Zadok <ezk at cs.sunysb.edu>
Date:   Tue Sep 25 00:44:44 2007 -0400

    Unionfs: cast page->index loff_t before shifting
    
    Fixes bugs in number promotion/demotion computation, as per
    <http://lkml.org/lkml/2007/9/20/17>
    
    Signed-off-by: Erez Zadok <ezk at cs.sunysb.edu>

diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
index 88ef6a6..37af979 100644
--- a/fs/unionfs/mmap.c
+++ b/fs/unionfs/mmap.c
@@ -179,7 +179,8 @@ static int unionfs_do_readpage(struct file *file, struct page *page)
 	 * may be a little slower, but a lot safer, as the VFS does a lot of
 	 * the necessary magic for us.
 	 */
-	offset = lower_file->f_pos = (page->index << PAGE_CACHE_SHIFT);
+	offset = lower_file->f_pos =
+		((loff_t) page->index << PAGE_CACHE_SHIFT);
 	old_fs = get_fs();
 	set_fs(KERNEL_DS);
 	err = vfs_read(lower_file, page_data, PAGE_CACHE_SIZE,
@@ -289,7 +290,7 @@ static int unionfs_commit_write(struct file *file, struct page *page,
 	BUG_ON(lower_file == NULL);
 
 	page_data = (char *)kmap(page);
-	lower_file->f_pos = (page->index << PAGE_CACHE_SHIFT) + from;
+	lower_file->f_pos = ((loff_t) page->index << PAGE_CACHE_SHIFT) + from;
 
 	/*
 	 * SP: I use vfs_write instead of copying page data and the