[patch 1/4] ext2 convert to new aops fix

[Nick Piggin <npiggin@suse.de>]

These are some write_begin aops conversion fixes for the current -mm
tree. I didn't quite get it building, but did compile test at least.

Patches all address the same silly bug in my directory pagecache
conversions.

---
ext2 directory code has a conversion overflow. Spotted by Hugh Dickins.
Probably would hurt anyone in practice unless they are using >4GB directories,
but must fix.

Signed-off-by: Nick Piggin <npiggin@suse.de>

Index: linux-2.6/fs/ext2/dir.c
===================================================================
--- linux-2.6.orig/fs/ext2/dir.c
+++ linux-2.6/fs/ext2/dir.c
@@ -424,7 +424,7 @@ ino_t ext2_inode_by_name(struct inode * 
 void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
 			struct page *page, struct inode *inode)
 {
-	loff_t pos = (page->index << PAGE_CACHE_SHIFT) +
+	loff_t pos = page_offset(page) +
 			(char *) de - (char *) page_address(page);
 	unsigned len = le16_to_cpu(de->rec_len);
 	int err;
@@ -511,7 +511,7 @@ int ext2_add_link (struct dentry *dentry
 	return -EINVAL;
 
 got_it:
-	pos = (page->index << PAGE_CACHE_SHIFT) +
+	pos = page_offset(page) +
 		(char*)de - (char*)page_address(page);
 	err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0,
 							&page, NULL);
@@ -569,7 +569,7 @@ int ext2_delete_entry (struct ext2_dir_e
 	}
 	if (pde)
 		from = (char*)pde - (char*)page_address(page);
-	pos = (page->index << PAGE_CACHE_SHIFT) + from;
+	pos = page_offset(page) + from;
 	lock_page(page);
 	err = __ext2_write_begin(NULL, page->mapping, pos, to - from, 0,
 							&page, NULL);